This document provides an overview of common surface finishes used in the printed circuit board industry. It discusses the key functions of surface finishes in protecting copper connectors, minimizing tarnish, and ensuring good solderability. The most widely used finishes are ENIG, OSP, immersion tin, immersion silver, and HASL. Each finish has unique processing steps and pros and cons depending on factors like performance, reliability, and cost. ENIG is the largest market but also most expensive, while OSP and immersion finishes are cheaper alternatives. The document provides detailed descriptions of the application and characteristics of each type of surface finish.
This chapter discusses materials commonly used for mechanical shaft seal parts, including seal faces. Carbon graphite is widely used as a seal face material due to its low friction properties. Other common seal face materials include impregnated carbon graphite, alumina, tungsten carbide, silicon carbide, and diamond coatings. The properties, advantages, and limitations of each material are described. Tests are also conducted to evaluate seals using different material pairings.
The document discusses wear and techniques to improve wear resistance. It defines different types of wear including adhesive, abrasive, corrosive, surface fatigue, and erosion wear. Traditional techniques to improve wear resistance such as painting, electroplating, and galvanization are described. More advanced techniques like physical vapor deposition, chemical vapor deposition, ion implantation, and laser coating are also summarized. The presentation provides details on each technique and their effects on wear resistance.
This document provides information on cast and die systems used for fabricating dental restorations. It begins with an introduction stating that direct fabrication of patterns in the mouth is difficult, so a cast and die system is used to capture tooth information and transfer it to the lab. It then reviews literature on the accuracy of stone dies and different die materials. Key requirements for casts, dies and die materials are outlined. Common die materials like gypsum, resins and electroplated metals are described along with their properties and advantages. Different cast and die systems using dowel pins, trays and removable dies are also summarized.
Yttria stabilized zirconia (YSZ) is an effective thermal barrier coating for aerospace applications. It has a high melting point of 3200°C and low thermal conductivity, protecting metal components from extreme operating temperatures. YSZ also has high fracture toughness and hardness. It is commonly applied using electron beam physical vapor deposition or atmospheric plasma spraying. YSZ increases the lifetime of parts like turbine blades by allowing higher operating temperatures while insulating the metal alloy underneath. Proper processing and additions like pyrochlore can further improve YSZ's performance and durability over long periods of use.
This lecture describes the key factors associated with conversion coatings on aluminium can be appreciated, such as general and local behaviour of the aluminium surface, range of conversion coatings and interrelationships, requirements of conversion coating, tailor-making of coatings, current and future issues. Some familiarity with the subject matter covered in TALAT This lectures 5101, 5102, 5201 is assumed.
TALAT Lecture 5104: Basic Approaches to Prevent Corrosion of AluminiumCORE-Materials
This lecture describes important measures for the prevention of corrosion of unprotected, bare
aluminium. Basic knowledge of corrosion behaviour of aluminium and some knowledge of the electrochemical nature of corrosion is assumed
TALAT Lecture 5101: Surface Characteristics of Aluminium and Aluminium AlloysCORE-Materials
This lecture provides a realistic view of the aluminium surface in order to understand the need for "effective" surface treatment. Some knowledge in aluminium metallurgy is assumed.
Dental amalgam is an alloy used in dentistry as a filling material. It contains mercury and other metals such as silver, tin, and copper. Amalgam is used for fillings in back teeth and to restore crowns. There are different types of amalgam based on their composition and particle shape. The properties and performance of amalgam depend on factors like mercury content, alloy composition, trituration, and condensation technique. While amalgam is inexpensive and durable, it also has disadvantages like poor aesthetics, potential toxicity, and marginal breakdown over time.
This chapter discusses materials commonly used for mechanical shaft seal parts, including seal faces. Carbon graphite is widely used as a seal face material due to its low friction properties. Other common seal face materials include impregnated carbon graphite, alumina, tungsten carbide, silicon carbide, and diamond coatings. The properties, advantages, and limitations of each material are described. Tests are also conducted to evaluate seals using different material pairings.
The document discusses wear and techniques to improve wear resistance. It defines different types of wear including adhesive, abrasive, corrosive, surface fatigue, and erosion wear. Traditional techniques to improve wear resistance such as painting, electroplating, and galvanization are described. More advanced techniques like physical vapor deposition, chemical vapor deposition, ion implantation, and laser coating are also summarized. The presentation provides details on each technique and their effects on wear resistance.
This document provides information on cast and die systems used for fabricating dental restorations. It begins with an introduction stating that direct fabrication of patterns in the mouth is difficult, so a cast and die system is used to capture tooth information and transfer it to the lab. It then reviews literature on the accuracy of stone dies and different die materials. Key requirements for casts, dies and die materials are outlined. Common die materials like gypsum, resins and electroplated metals are described along with their properties and advantages. Different cast and die systems using dowel pins, trays and removable dies are also summarized.
Yttria stabilized zirconia (YSZ) is an effective thermal barrier coating for aerospace applications. It has a high melting point of 3200°C and low thermal conductivity, protecting metal components from extreme operating temperatures. YSZ also has high fracture toughness and hardness. It is commonly applied using electron beam physical vapor deposition or atmospheric plasma spraying. YSZ increases the lifetime of parts like turbine blades by allowing higher operating temperatures while insulating the metal alloy underneath. Proper processing and additions like pyrochlore can further improve YSZ's performance and durability over long periods of use.
This lecture describes the key factors associated with conversion coatings on aluminium can be appreciated, such as general and local behaviour of the aluminium surface, range of conversion coatings and interrelationships, requirements of conversion coating, tailor-making of coatings, current and future issues. Some familiarity with the subject matter covered in TALAT This lectures 5101, 5102, 5201 is assumed.
TALAT Lecture 5104: Basic Approaches to Prevent Corrosion of AluminiumCORE-Materials
This lecture describes important measures for the prevention of corrosion of unprotected, bare
aluminium. Basic knowledge of corrosion behaviour of aluminium and some knowledge of the electrochemical nature of corrosion is assumed
TALAT Lecture 5101: Surface Characteristics of Aluminium and Aluminium AlloysCORE-Materials
This lecture provides a realistic view of the aluminium surface in order to understand the need for "effective" surface treatment. Some knowledge in aluminium metallurgy is assumed.
Dental amalgam is an alloy used in dentistry as a filling material. It contains mercury and other metals such as silver, tin, and copper. Amalgam is used for fillings in back teeth and to restore crowns. There are different types of amalgam based on their composition and particle shape. The properties and performance of amalgam depend on factors like mercury content, alloy composition, trituration, and condensation technique. While amalgam is inexpensive and durable, it also has disadvantages like poor aesthetics, potential toxicity, and marginal breakdown over time.
Experimental Study on Surface Roughness by Using Abrasive ParticlesIJERA Editor
New advancement of technology and never satisfying demands of the civilization are putting huge pressure on the natural fuel resources and these resources are at a constant threat to its sustainability. Surface finish has a vital influence on functional properties such as wear resistance and power loss due to friction on most of the engineering components. Voltage, mesh number, revolutions per minute (rpm) of electromagnet, and percentage weight of abrasives has been identified as important process parameters affecting surface roughness. The experiments were planned using response surface methodology and percentage change in surface roughness (ΔRa) was considered as response. Analysis of experimental data showed that percentage change in surface roughness (ΔRa) was highly influenced by mesh number followed by percentage weight of abrasives, rpm of electromagnet, and voltage. The process has been investigated extensively in the finishing of cylindrical surfaces. The surface finish was found to improve significantly with an increase in the grain size, relative size of abrasive particles vis-à-vis the iron particles, feed rate and current. Super finishing is a micro-finishing process that produces a controlled and smooth surface condition on work pieces. It is not primarily a sizing operation, its major purpose is to produce a surface on a work piece capable of sustaining uneven distribution of a load by improving the geometrical accuracy. The wear life of the parts micro finished to maximum smoothness is extended considerably. According to the design of experimentation, mathematical model for Lapping operation on advance ceramic material is proposed. In order to get minimum values of the surface roughness, optimization of the mathematical model is done and optimal operation of the examined factors is going to be determined. The obtained res
Monobond Etch & Prime is a self-etching single-component glass-ceramic primer that produces a similar adhesive bond strength as the conventional procedure with hydrofluoric acid and silane. The innovative new material from Ivoclar Vivadent eliminates the need for using hydrofluoric acid as the etchant and the concomitant separate working steps. Monobond Etch & Prime therefore enables safe, easy and reliable conditioning of all glass-ceramic restorations in the practice.
Die materials /certified fixed orthodontic courses by Indian dental academy Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
This document provides information on dental amalgam, including:
- A brief history noting amalgam has been used for over 150 years and was originally made by filing silver coins and mixing with mercury.
- The components and microstructure of amalgam, including how it is composed of a mixture of silver/tin/copper alloy and mercury that amalgamates during manipulation.
- The classification, properties, manipulation techniques, indications and contraindications for amalgam restorations.
- Potential failures of amalgam restorations and their causes, as well as precautions needed due to mercury toxicity.
Adding rhenium to the binder in cemented carbide finalEyvind Engblom
The document discusses adding rhenium (Re) to the cobalt (Co) binder phase in cemented carbides. Two samples were investigated - one containing tungsten carbide (WC), cobalt, and rhenium (WC-Co-Re), and one reference sample containing just WC and Co (WC-Co).
The WC-Co-Re sample showed an increase in hardness of 150 MPa compared to the reference sample. Scanning electron microscopy and electron dispersive x-ray spectroscopy analysis revealed that the rhenium dissolved together with the cobalt in the binder phase.
The aim of adding rhenium was to improve the high-temperature properties of the cobalt binder by
Zinc phosphate cement is an older luting cement that serves as a standard for comparison. It has low hardness and high solubility. When mixed, the powder and liquid undergo an exothermic reaction where zinc ions are released and react with aluminum and phosphoric acid to form a zinc aluminophosphate gel. It has good compressive strength but no chemical adhesion and can cause pulp irritation due to its initial low pH. The powder contains mainly zinc oxide and magnesium oxide while the liquid contains phosphoric acid, water, and aluminum.
Surface Processing Operation includes material surface cleaning and surface treating processes which is physically and/or chemically to alter surface texture, Mechanical properties, Physical properties, Chemical Properties etc, to have a better material.
Dental amalgam power point by Dr.Kazhan O. Abdulrahmanabas_lb
This document discusses dental amalgam, including its composition as an alloy containing mercury and other metals. It describes the physical properties and configurations of amalgam alloys, including particle size and shape. The document outlines the clinical manipulation process for dental amalgam, including trituration, condensation, carving and finishing. It discusses factors that influence the properties and performance of amalgam restorations, such as strength, creep, corrosion resistance and marginal breakdown over time. The document also addresses the safety and toxicity of dental amalgam.
Powder’s Morphology and Cross-sectional SEM Images for Nickel based hard coat...Venkataraman Bandaru
This document discusses nickel-based hard coatings for wear, oxidation, and corrosion protection. It provides information on powder production methods, including water or gas atomization, fused or sintered and crushed powders, agglomerated and sintered powders, clad powders, and blend powders. It also discusses various powder materials like pure metals, alloys, superalloys, and carbides, providing examples of each along with SEM images of their powder cross-sections. The coatings are intended to improve surface properties and provide protection in industrial applications.
Lost Foam Casting defects are influential and complex, and cross each other.
The quality of raw and auxiliary materials is very important, in that case the procurement of material has to be very careful.
Fine process management and convergence, to strengthen the fine control of the process.
Responsibility is more important than the system, to strengthen discipline and supervision, assign responsibility to every staff.
Improve the theoretical quality of workers and good operating habits.
The document discusses a study on the durability properties of self-compacting concrete where fine aggregate is partially replaced with copper slag. Six concrete mixes were prepared with 0%, 20%, 40%, 60%, and 80% replacement of fine aggregate. Tests were performed on fresh and hardened concrete to evaluate workability and durability properties like acid resistance, sulfate attack, and corrosion resistance. The results showed that replacing fine aggregate with copper slag did not negatively affect the workability or durability of the self-compacting concrete.
Alpha Metal Finishing provided a hardcoat anodizing lunch and learn presentation in May 2014. Special thanks to Rob Pawson from Reliant Aluminum Products for assisting us.
The document discusses different types of dental cements including zinc phosphate cement, zinc polycarboxylate cement, glass ionomer cement, resin modified glass ionomer cement, metal reinforced glass ionomer cement, and resin cements. It describes the composition, setting reactions, properties, advantages, and disadvantages of each cement type. The document provides details on mixing and manipulating procedures for different cements.
Optimization of ceramic shell mold materials in investment castingeSAT Publishing House
This document summarizes research into optimizing ceramic shell mold materials for investment casting. It describes how ceramic shell molds are made using refractory materials in slurries to form layers on a wax pattern. Zircon flour is commonly used but is costly. The research tested mixtures of zircon, alumina, and silica to reduce costs. Samples were cast in molds made with 100% zircon, 50% zircon and 50% alumina, and 70% zircon and 30% silica. The 100% zircon mold produced a sample with the best surface finish and fewest defects.
Zinc oxide eugenol (ZOE) cements have been used extensively in dentistry since the 1890s. They are available in various types for different applications. Type I ZOE cements are for short-term use as they have low strength. Type II have reinforcements for long-term cementation of permanent restorations. Type III are for interim treatment and Type IV are low strength materials used as liners. Modified ZOE cements have been introduced to improve strength by adding reinforcing agents like EBA, alumina or polymers. ZOE cements have properties like bacteriostatic effect, obtundency and low irritation to pulp. They are still commonly used as endodontic sealers,
Surface preparation is critical for coating performance and longevity. It involves cleaning the surface of contaminants like mill scale, rust, grease and dirt. The level of cleaning depends on factors like the substrate material and coating system. Common preparation methods include solvent cleaning, abrasive blasting and chemical treatments. Proper surface preparation can increase coating adhesion and the protective life of a paint system by over 80%.
This document summarizes the history and types of posterior composite resin restorations. It discusses the introduction of microfill, hybrid, and microhybrid composites in the 1980s-1990s with improvements in physical properties but continued problems with wear. More recent developments include packable and flowable composites, with packables having high filler loading and strength for larger restorations, while flowables are low viscosity for non-stress areas. The document outlines techniques for isolation, cavity preparation, pulp protection, finishing, and polishing of posterior composite resins.
The document discusses the principles and evolution of adhesive dentistry. It explains that adhesive dentistry aims to create adhesion between tooth structure and restorative materials. Historically, acid etching of enamel by Buonocore in 1955 improved adhesion of acrylic resin to enamel and marked the beginning of adhesive dentistry. The document covers topics such as the principles of adhesion, mechanisms of adhesion, factors affecting adhesion, dentin bonding systems, classification of bonding agents, and challenges in adhesion.
Calcium phosphate bone cement is a self-setting cement that forms either calcium-deficient hydroxyapatite or brushite when mixed with water. It has two main advantages - it is injectable and self-sets in vivo at body temperature. Calcium phosphate cement consists of calcium phosphate powders that harden upon mixing with water to form a paste. This paste sets to become either calcium-deficient hydroxyapatite or brushite depending on the pH. It has properties like osteoconduction, osteoinduction and osseointegration that make it suitable for bone grafting applications.
The document discusses challenges and guidelines for printing solder paste with step stencils. It analyzes how factors like squeegee speed, pressure, angle, and material affect the amount of paste residue near step edges. Testing showed circular apertures near steep step downs had lower transfer efficiency than oblong apertures due to more residue. Guidelines recommend reducing speed, increasing pressure, changing the angle to 45°, and using a polymer squeegee to minimize residue for consistent paste transfer. Apertures far from step edges showed high transfer efficiency regardless of geometry or step height.
Experimental Study on Surface Roughness by Using Abrasive ParticlesIJERA Editor
New advancement of technology and never satisfying demands of the civilization are putting huge pressure on the natural fuel resources and these resources are at a constant threat to its sustainability. Surface finish has a vital influence on functional properties such as wear resistance and power loss due to friction on most of the engineering components. Voltage, mesh number, revolutions per minute (rpm) of electromagnet, and percentage weight of abrasives has been identified as important process parameters affecting surface roughness. The experiments were planned using response surface methodology and percentage change in surface roughness (ΔRa) was considered as response. Analysis of experimental data showed that percentage change in surface roughness (ΔRa) was highly influenced by mesh number followed by percentage weight of abrasives, rpm of electromagnet, and voltage. The process has been investigated extensively in the finishing of cylindrical surfaces. The surface finish was found to improve significantly with an increase in the grain size, relative size of abrasive particles vis-à-vis the iron particles, feed rate and current. Super finishing is a micro-finishing process that produces a controlled and smooth surface condition on work pieces. It is not primarily a sizing operation, its major purpose is to produce a surface on a work piece capable of sustaining uneven distribution of a load by improving the geometrical accuracy. The wear life of the parts micro finished to maximum smoothness is extended considerably. According to the design of experimentation, mathematical model for Lapping operation on advance ceramic material is proposed. In order to get minimum values of the surface roughness, optimization of the mathematical model is done and optimal operation of the examined factors is going to be determined. The obtained res
Monobond Etch & Prime is a self-etching single-component glass-ceramic primer that produces a similar adhesive bond strength as the conventional procedure with hydrofluoric acid and silane. The innovative new material from Ivoclar Vivadent eliminates the need for using hydrofluoric acid as the etchant and the concomitant separate working steps. Monobond Etch & Prime therefore enables safe, easy and reliable conditioning of all glass-ceramic restorations in the practice.
Die materials /certified fixed orthodontic courses by Indian dental academy Indian dental academy
Welcome to Indian Dental Academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy has a unique training program & curriculum that provides students with exceptional clinical skills and enabling them to return to their office with high level confidence and start treating patients
State of the art comprehensive training-Faculty of world wide repute &Very affordable.
This document provides information on dental amalgam, including:
- A brief history noting amalgam has been used for over 150 years and was originally made by filing silver coins and mixing with mercury.
- The components and microstructure of amalgam, including how it is composed of a mixture of silver/tin/copper alloy and mercury that amalgamates during manipulation.
- The classification, properties, manipulation techniques, indications and contraindications for amalgam restorations.
- Potential failures of amalgam restorations and their causes, as well as precautions needed due to mercury toxicity.
Adding rhenium to the binder in cemented carbide finalEyvind Engblom
The document discusses adding rhenium (Re) to the cobalt (Co) binder phase in cemented carbides. Two samples were investigated - one containing tungsten carbide (WC), cobalt, and rhenium (WC-Co-Re), and one reference sample containing just WC and Co (WC-Co).
The WC-Co-Re sample showed an increase in hardness of 150 MPa compared to the reference sample. Scanning electron microscopy and electron dispersive x-ray spectroscopy analysis revealed that the rhenium dissolved together with the cobalt in the binder phase.
The aim of adding rhenium was to improve the high-temperature properties of the cobalt binder by
Zinc phosphate cement is an older luting cement that serves as a standard for comparison. It has low hardness and high solubility. When mixed, the powder and liquid undergo an exothermic reaction where zinc ions are released and react with aluminum and phosphoric acid to form a zinc aluminophosphate gel. It has good compressive strength but no chemical adhesion and can cause pulp irritation due to its initial low pH. The powder contains mainly zinc oxide and magnesium oxide while the liquid contains phosphoric acid, water, and aluminum.
Surface Processing Operation includes material surface cleaning and surface treating processes which is physically and/or chemically to alter surface texture, Mechanical properties, Physical properties, Chemical Properties etc, to have a better material.
Dental amalgam power point by Dr.Kazhan O. Abdulrahmanabas_lb
This document discusses dental amalgam, including its composition as an alloy containing mercury and other metals. It describes the physical properties and configurations of amalgam alloys, including particle size and shape. The document outlines the clinical manipulation process for dental amalgam, including trituration, condensation, carving and finishing. It discusses factors that influence the properties and performance of amalgam restorations, such as strength, creep, corrosion resistance and marginal breakdown over time. The document also addresses the safety and toxicity of dental amalgam.
Powder’s Morphology and Cross-sectional SEM Images for Nickel based hard coat...Venkataraman Bandaru
This document discusses nickel-based hard coatings for wear, oxidation, and corrosion protection. It provides information on powder production methods, including water or gas atomization, fused or sintered and crushed powders, agglomerated and sintered powders, clad powders, and blend powders. It also discusses various powder materials like pure metals, alloys, superalloys, and carbides, providing examples of each along with SEM images of their powder cross-sections. The coatings are intended to improve surface properties and provide protection in industrial applications.
Lost Foam Casting defects are influential and complex, and cross each other.
The quality of raw and auxiliary materials is very important, in that case the procurement of material has to be very careful.
Fine process management and convergence, to strengthen the fine control of the process.
Responsibility is more important than the system, to strengthen discipline and supervision, assign responsibility to every staff.
Improve the theoretical quality of workers and good operating habits.
The document discusses a study on the durability properties of self-compacting concrete where fine aggregate is partially replaced with copper slag. Six concrete mixes were prepared with 0%, 20%, 40%, 60%, and 80% replacement of fine aggregate. Tests were performed on fresh and hardened concrete to evaluate workability and durability properties like acid resistance, sulfate attack, and corrosion resistance. The results showed that replacing fine aggregate with copper slag did not negatively affect the workability or durability of the self-compacting concrete.
Alpha Metal Finishing provided a hardcoat anodizing lunch and learn presentation in May 2014. Special thanks to Rob Pawson from Reliant Aluminum Products for assisting us.
The document discusses different types of dental cements including zinc phosphate cement, zinc polycarboxylate cement, glass ionomer cement, resin modified glass ionomer cement, metal reinforced glass ionomer cement, and resin cements. It describes the composition, setting reactions, properties, advantages, and disadvantages of each cement type. The document provides details on mixing and manipulating procedures for different cements.
Optimization of ceramic shell mold materials in investment castingeSAT Publishing House
This document summarizes research into optimizing ceramic shell mold materials for investment casting. It describes how ceramic shell molds are made using refractory materials in slurries to form layers on a wax pattern. Zircon flour is commonly used but is costly. The research tested mixtures of zircon, alumina, and silica to reduce costs. Samples were cast in molds made with 100% zircon, 50% zircon and 50% alumina, and 70% zircon and 30% silica. The 100% zircon mold produced a sample with the best surface finish and fewest defects.
Zinc oxide eugenol (ZOE) cements have been used extensively in dentistry since the 1890s. They are available in various types for different applications. Type I ZOE cements are for short-term use as they have low strength. Type II have reinforcements for long-term cementation of permanent restorations. Type III are for interim treatment and Type IV are low strength materials used as liners. Modified ZOE cements have been introduced to improve strength by adding reinforcing agents like EBA, alumina or polymers. ZOE cements have properties like bacteriostatic effect, obtundency and low irritation to pulp. They are still commonly used as endodontic sealers,
Surface preparation is critical for coating performance and longevity. It involves cleaning the surface of contaminants like mill scale, rust, grease and dirt. The level of cleaning depends on factors like the substrate material and coating system. Common preparation methods include solvent cleaning, abrasive blasting and chemical treatments. Proper surface preparation can increase coating adhesion and the protective life of a paint system by over 80%.
This document summarizes the history and types of posterior composite resin restorations. It discusses the introduction of microfill, hybrid, and microhybrid composites in the 1980s-1990s with improvements in physical properties but continued problems with wear. More recent developments include packable and flowable composites, with packables having high filler loading and strength for larger restorations, while flowables are low viscosity for non-stress areas. The document outlines techniques for isolation, cavity preparation, pulp protection, finishing, and polishing of posterior composite resins.
The document discusses the principles and evolution of adhesive dentistry. It explains that adhesive dentistry aims to create adhesion between tooth structure and restorative materials. Historically, acid etching of enamel by Buonocore in 1955 improved adhesion of acrylic resin to enamel and marked the beginning of adhesive dentistry. The document covers topics such as the principles of adhesion, mechanisms of adhesion, factors affecting adhesion, dentin bonding systems, classification of bonding agents, and challenges in adhesion.
Calcium phosphate bone cement is a self-setting cement that forms either calcium-deficient hydroxyapatite or brushite when mixed with water. It has two main advantages - it is injectable and self-sets in vivo at body temperature. Calcium phosphate cement consists of calcium phosphate powders that harden upon mixing with water to form a paste. This paste sets to become either calcium-deficient hydroxyapatite or brushite depending on the pH. It has properties like osteoconduction, osteoinduction and osseointegration that make it suitable for bone grafting applications.
The document discusses challenges and guidelines for printing solder paste with step stencils. It analyzes how factors like squeegee speed, pressure, angle, and material affect the amount of paste residue near step edges. Testing showed circular apertures near steep step downs had lower transfer efficiency than oblong apertures due to more residue. Guidelines recommend reducing speed, increasing pressure, changing the angle to 45°, and using a polymer squeegee to minimize residue for consistent paste transfer. Apertures far from step edges showed high transfer efficiency regardless of geometry or step height.
- AT&S is a leading high-tech printed circuit board (PCB) company based in Austria with production facilities in Europe and Asia.
- The company is strategically focusing on high-end technologies like HDI PCBs and IC substrates for applications in mobile devices, automotive, industrial, and medical markets.
- AT&S is currently investing €480 million to build a new plant in Chongqing, China that will produce IC substrates and substrate-like PCBs starting in 2016, allowing the company to enter new high-growth market segments.
Modern electronic medical equipment is used for experimental, preventive and clinical research and treatment. Medical diagnostics utilizes laboratory tests, ultrasound exams, functional assessments, and computer tomography to examine internal organs, processes, and detect dysfunctions. Key electronic devices and instruments receive, record, transmit biomedical information or dispense physical treatments like microwave therapy or electrosurgery.
Sensors for Home Healthcare Applications: Market & Technology Analysis 2013 R...Yole Developpement
The market for sensors in home healthcare applications will explode from $559M in 2013 to $1.2B by 2018!
Sensors for home care will explode over the next five years
From 2000 - 2050, the proportion of the world's population aged 60 and over will grow from about 16% to 25% -- an increase linked to a marked growth of chronic diseases (Alzheimer's, diabetes, cancers, etc.). Healthcare systems’ rising costs and a physicians’ shortage are paving the way for increased home care.
Sensors previously developed for non-medical applications are transitioning to home care applications, and the market for sensors dedicated to home care applications is poised to grow from $559M in 2013 to $1.2B by 2018.
During Yole's research, the following sensors were investigated: accelerometers, barometers, electrochemical biosensors, flow sensors, gyroscopes, humidity sensors, IR temperature sensors, magnetometers, microfluidic chips, microphones, photodetectors, pressure sensors, proximity IR sensors, RF MEMS, RFID, and strain sensors. For each sensors, Yole’s Home Care Report provides market data and unit/value forecasts.
Collectively, these sensors have numerous applications in the home care market, from fall detection systems to tremor monitoring in Parkinson’s disease.
Today, the three most-used sensors are photodetectors, pressure sensors and electrochemical sensors.
A highly segmented market
Home care, also called home healthcare, refers to the at-home care provided to a person with special needs. This includes people who are ageing, chronically ill, recovering from surgery, or disabled.
Transferring a patient from a hospital to his/her home implies a relocation of care systems. In order to maintain the same level of care quality with less human involvement, home care sensors are vital replacements for specific applications ordinarily performed by nurses, such as guaranteeing the patient’s comfort, ensuring their safety, monitoring body parameters and treatments, and drug delivery.
Using a disruptive segmentation, Yole’s analysts have gathered all of the information necessary for understanding each application’s market needs.
More information on that report at http://www.i-micronews.com/reports/Sensors-Home-Healthcare-Applications-Market-Analysis/1/409/
Fan-Out and Embedded Die: Technologies & Market Trends 2015 Report by Yole De...Yole Developpement
Fan-Out and Embedded Die: Two promising Wafer/Panel-Level-Packaging technologies. What are the next steps for the growth?
Fan-Out Wafer Level Packaging is already in high-volume – but it’s about to grow even more strongly
Fan-Out Wafer Level Packaging (FOWLP) started volume commercialization in 2009/2010 and started promisingly, with initial push by Intel Mobile. However, it was limited to a narrow range of applications – essentially single die packages for cell phone baseband chips – reaching its limit in 2011. In 2012 big fab-less wireless/mobile players started slowly volume production after qualifying the technology...
Status of The Advanced Packaging Industry_Yole Développement reportYole Developpement
IoT driven semiconductor industry consolidation is reflecting into a highly dynamic Advanced Packaging landscape. Demand for advanced packaging and market size is increasing. Focus is turning
to integration and wafer level packages to enable a functionality driven roadmap and revive the cost/performance curve.
3DIC and 2.5D TSV Interconnect for Advanced Packaging: 2016 Business Update -...Yole Developpement
3D TSV technology is becoming a key solution platform for heterogeneous interconnection, high end memory and performance applications.
TSVs have been adopted for MEMS, Sensors, and Memory devices. What will the next technology driver be?
Through-silicon vias (TSVs) have now become the preferred interconnect choice for high-end memory. They are also an enabling technology for heterogeneous integration of logic circuits with CMOS image sensors (CIS), MEMS, sensors, and radio frequency (RF) filters. In the near future they will also enable photonics and LED function integration. The market for 3D TSV and 2.5D interconnect is expected to reach around two million wafers in 2020, expanding at a 22% compound annual growth rate (CAGR). The growth is driven by increased adoption of 3D memory devices in high-end graphics, high-performance computing, networking and data centers, and penetration into new areas, including fingerprint and ambient light sensors, RF filters and LEDs.
CIS still commanded more than 70% % share of TSV market wafer volume in 2015, although this will decrease to around 60% by 2020. This is primarily due to the growth of the other TSV applications, led by 3D memories, RF filters and fingerprint sensors (FPS). However, hybrid stacked technology, which uses direct copper-copper bonding, not TSVs, will penetrate around 30% of CIS production by 2020. The TSV markets for RF filters and FPS are expected to reach around $1.6B and $0.5B by 2020 respectively. The report will explain the market’s dynamics and give an overview of all segments and key markets. It will also provide market data in terms of revenues, units and wafer starts for all the different segments, including market share.
Sensors for Biometry and Recognition - 2016 Report by Yole DeveloppementYole Developpement
In a global biometric hardware market worth over $4B, traditional fingerprint/palm sensors still monopolize 95% of the market, but face and iris sensors lie in wait.
Fingerprint technology impressively dominates the market - but changes are expected
Due to historical reasons, like the criminal fingerprint database established by the FBI with ink-based techniques, fingerprint sensing is the most common biometric technology currently used, by far. We estimate that the annual revenues generated by fingerprint-based solutions are currently $4.25B, representing 95% of the hardware market. Fingerprint sensing dominates technologies like iris, face, palm or voice recognition, because it meets almost all the requirements of a “perfect” biometric recognition technology. It is robust, stable and repeatable, time-invariant, difficult to spoof, has a distinctive meaning, is "unique" amongst a population, accessible, easy to use and acceptably non-intrusive. All other biometric technologies do not yet fulfill those requirements as specifically as fingerprint technology. Hardware revenues generated by the other biometric technologies are relatively low, estimated at $250M, mostly from iris and face recognition. This report identifies the players in the biometric hardware market, and provides technology, market and trend evolution insights. The fingerprint market has experienced an incredible volume increase in the consumer market with the adoption of the active capacitance detection on an increasing number of smartphones to answer the demand of online identification, mobile payment and unlocking applications. Diverse technologies, such as optical, thermal, and Piezoelectric Micromachined Ultrasonic Transducers (PMUT), are also trying to penetrate the consumer market, but are still very limited. The industrial and homeland/security markets are still widely using optical technology. Other biometric solutions like iris, face or voice recognition have been introduced but with a limited impact. Their performance hasn’t yet reached the requirements with regards to cost, reliability, false rejection rate and false acceptance rate to significantly penetrate either the consumer, industrial or homeland/security markets....
More information on that report: http://www.i-micronews.com/report/product/sensors-for-biometry-and-recognition.html
Advanced Substrates Overview: From IC Package to Board - 2017 Report by Yole ...Yole Developpement
How can advanced substrates and boards bridge the gap created by front-end scaling?
Advanced substrates as a key enabler of future products and markets
In an uncertain, transformative semiconductor market, advanced packaging is one of the key technologies offering stability and a long-term solution. On one hand it can adapt to product diversification, offering more functionality, system integration, and performance, as well as potentially lower manufacturing cost; and on the other hand it can adhere to future scaling requirements. Advanced substrates are the key interconnect component of advanced packaging architectures and are critical in enabling future products and markets. For this reason, Yole has established this stand-alone dedicated advanced substrate activity, focused on exploring the market and technologies of PCBs, package substrates and RDLs. This first report will serve as an overview of advanced substrate technologies, markets, and supply chain, to be supported by subsequent in-depth reports.
Today’s advanced substrates in volume are Flip Chip (FC) substrates, 2.5D/3D TSV assemblies, and thin-film RDLs (Fan-Out WLP, or “FOWLP”) below an L/S resolution of 15/15 um and with transition below L/S < 10/10 um. These advanced substrates are traditionally linked to higher-end logic (CPUs/GPUs, DSPs, etc.) driven by ICs in the latest technology nodes in the computing, networking, mobile, and high-end consumer market segments (gaming, HD/Smart TV). However, due to additional form factor and low power demands, WLP and advanced FC substrates are also widespread in majority of smartphone functions: application processors, baseband, transceivers, filters, amplifiers, WiFi modules, drivers, codecs, power management, etc.
For more information, please visit our website: http://www.i-micronews.com/reports.html
This presentation outlines some of the most exciting medical MEMS and sensors devices that were introduced to the marketplace in the past few years. Some of the devices are already in volume production, and some are still being commercialized.
The document discusses the PCB manufacturing process. It describes what a PCB is and the different types of PCBs. It then explains the key layers that make up a PCB, including the substrate, copper layers, solder mask, and silkscreen. The document proceeds to outline several stages of the PCB manufacturing process, including PCB drilling, film development, etching, plating, micro-etching. The overall process produces circuit boards by applying conductive traces to a non-conductive substrate.
The document discusses the base coat used in high vacuum metalizing processes. The base coat provides a smooth, glossy surface for metal like aluminum or chromium to be deposited onto. It must have good leveling properties to cover roughness and have low shrinkage during curing. Modern base coats have improved leveling from reduced solvents and shrinkage compared to older nitrocellulose-based coatings. The hardness of the base coat is also important so deposited metals like chromium don't cause cracking as they shrink.
Study of sliding wear rate of hot rolled steel specimen subjected to Zirconia...IJERA Editor
Wear is nothing but loss of material by usage. In a mechanical industry mechanical components will operate
under severe load, temperature and high speeds. Under such a type of situation, when metal to metal contact take
place the surfaces that comes in contact is subjected to wear. These should be considered as a serious affair in an
industry because if the process of wear continues it can reduce service life of the component and also to the
entire mechanical system to which the component has been used. In the light of the above the present work
mainly deals with the study of wear behavior of hot rolled steel with and without zirconia coating on the contact
surface and the effect of zirconia coating with varying thickness.
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This paper will present a rigorous method for evaluating the performance and economic benefits of solder paste stencil nano-coatings. Criterion such as underside cleaning, bridging, transfer efficiency across SARs, solder paste deposit geometry, post-print cleaning, and abrasion resistance of the coating, will all be considered and weighted. Performance of currently available coatings will be compared. A discussion of the economic impact on current and future SMT design will be included.
These processes are sometimes referred to as post-processing. They play a very important role in the appearance, function and life of the product. Broadly, these are processes that affect either a thin layer on the surface of the part itself, or add a thin layer on top of the surface of the part. There are different coating and surface treatments processes, with different applications, uses, etc. The important uses include:
• Improving the hardness
• Improving the wear resistance
• Controlling friction, Reduction of adhesion, improving the lubrication, etc.
• Improving corrosion resistance
• Improving aesthetics
9.1. Mechanical hardening of the surface
These methods apply mechanical impulses (e.g. light hammering) on the surface of a metallic part. This hammering action causes tiny amount of plastic flow on the surface, resulting in the work-hardening of the surface layer due to the introduction of compressive residual stresses. Examples of these processes include Shot peening (uses tiny balls of metal or ceramic), Water-jet peening (uses a jet of water at high pressures, e.g. 400 MPa), or Laser peening (surface is hit by tiny impulses from a laser) – an expensive process used to improve fatigue strength of jet fan blades and turbine impellers.
Another method is explosive hardening, where a layer of explosive coated on the surface is blasted – the resulting impact results in tremendous increase in the surface hardness. This method is used to harden the surface of train rails.
9.2. Case hardening
This is a very common process that is used to harden the outer surface of parts such as gear teeth, cams, shafts, bearings, fasteners, pins, tools, molds, dies etc. In most of these types of components, the use involves dynamic forces, occasional impacts, and constant friction. Therefore the surface needs to be hard to prevent wear, but the bulk of the part should be tough (not brittle); this is achieved best by case hardening. There are several types of case hardening: in most cases, the chemical structure of the metal is changed by diffusing atoms of an alternate element which results in alterations to the micro-structure on the crystals on the surface.
This document summarizes a seminar report on thermal barrier coatings. It discusses that thermal barrier coatings consist of a metallic bond coat, thermally grown oxide layer, and ceramic top coat, most commonly yttria-stabilized zirconia. It reviews common deposition methods for thermal barrier coatings like air plasma spray, electron beam physical vapor deposition, and electrostatic spray assisted vapor deposition. The document concludes that thermal barrier coatings improve engine performance by allowing higher operating temperatures and reduce maintenance costs, making them an important technology with applications in industries like aerospace and automotive.
Could a disruptive new technology determine the future of pipeline safety? The answer is yes, and no. Pipeline safety is a complex problem; there is no ‘one size fits all’ solution. However, a decade of innovative research pioneered a new surface preparation category (surface decontamination) to address a previously overlooked and sizeable portion of problems underlying corrosion-related coating failures of pipelines and refinery tanks: ineffective surface preparation. The technology known as CleanWirx is so unique it is the only one in its category.
The document discusses the advantages and disadvantages of using an organic solderability preservative (OSP) finish on printed circuit boards. Some key advantages of OSP include providing flat solder pad surfaces for uniform solder paste application and eliminating solder bridging defects. OSP also provides excellent solderability for reflow and wave soldering. However, strict material handling is required as fingerprints can degrade the OSP coating. Care must also be taken when removing solder paste to avoid damaging the coating. OSP may not be suitable for all applications such as RF circuitry where a metal shield is required.
The document describes the manufacturing process for printed circuit boards. It involves several steps: 1) Pre-production engineering like file inspection and drill data generation. 2) CNC cutting and drilling of copper clad laminate. 3) Wet processing like direct plating system and electroplating to deposit copper. 4) Photo imaging and developing to transfer circuit images. 5) Etching and inspection to remove unwanted copper.
This document discusses the technique of "stripe coating" or "striping" which involves applying an extra layer of protective coating to irregular steel surfaces like edges, corners, crevices, bolts and welds in order to provide additional corrosion protection. These areas are difficult to adequately coat due to factors like reduced coating thickness, surface tension and coating shrinkage. The document describes how to prepare surfaces requiring stripe coating, such as by grinding edges to a rounded or chamfered profile. It also discusses best practices for applying the stripe coat, including using brushing for maximum control and coverage, applying it before or after the full coat, and ensuring the stripe coat is a different color for inspection. Stripe coating is especially important for surfaces
Surface Treatment of Aluminium by Anodizing: A Short ReviewIRJET Journal
The document summarizes the process of anodizing aluminum alloys. Anodizing involves electrochemically oxidizing the aluminum surface in an acid electrolyte bath to form a thicker, porous aluminum oxide layer for corrosion resistance. Key aspects of the process include: (1) the aluminum acts as the anode in the circuit and reacts to form aluminum ions that bond with oxygen to grow an oxide layer; (2) sulfuric acid is a commonly used electrolyte that produces a porous layer suitable for dyeing; and (3) sealing involves treatments that reduce porosity and prevent corrosion by sealing dye or lubricants inside the pores. Anodized aluminum has a variety of applications due to its enhanced corrosion resistance, ability to
Thermal spray coatings can enhance the wear resistance of materials. High-velocity oxy-fuel (HVOF) spraying is particularly effective due to producing very dense coatings with low porosity and high hardness. HVOF spraying involves melting or softening powder using a high-velocity oxy-fuel flame and projecting it onto a substrate. HVOF coatings have exceptional wear resistance, high bond strength, and are more cost-effective than other coating methods. Studies have shown that HVOF sprayed ceramic oxide and carbide coatings can significantly reduce wear in applications, performing better than uncoated materials. HVOF sprayed chromium carbide and tungsten carbide coatings are commonly used for their high wear resistance and ability to
This document describes the process for manufacturing printed circuit boards (PCBs) at Genus PCB. The key steps include:
1) Shearing and drilling copper clad laminate as per the design.
2) Plating through holes and depositing copper in desired areas using photo imaging and plating.
3) Stripping, etching, and stripping again to remove unwanted copper.
4) Applying solder mask and hot air leveling solder.
5) Testing and final quality control before separation and packaging of individual PCBs. Quality issues like shorts, breaks, or misalignment can occur if dust or films are not properly removed between steps.
TALAT Lecture 5301: The Surface Treatment and Coil Coating of AluminiumCORE-Materials
This lecture describes the continuous coil coating processes for aluminium in sufficient detail in order to understand the industrial coating technology and its application potential. General background in materials engineering and familiarity with the subject matter covered in TALAT This lectures 5100 and 5200 is assumed.
This document provides an overview of burr formation and deburring operations. It discusses how burrs form during machining and outlines various deburring methods including mechanical, thermal, chemical, and electrical processes. The most common deburring techniques used industrially are described, including manual deburring, abrasive blasting, bonded abrasive deburring, and their advantages and limitations. The document focuses on deburring aluminum alloy parts and the effects of different deburring methods on aluminum workpieces.
The document provides design guidelines for electroplating ABS and ABS/PC plastic parts. It discusses considerations for part design, plating uniformity, and racking. Key recommendations include using gradual transitions between wall thicknesses, rounding edges and corners, limiting depth of features like grooves and holes, and designing parts and racks to facilitate uniform plating and contact with rack tips. Consultation with molders and platers is advised to optimize part design for molding, plating and performance.
The document discusses various types of coatings used for plastic films, paper, and metal foils. It describes common coating techniques like comma coating, reverse roll coating, and Myer bar coating. It also discusses surface treatment methods like corona treatment and plasma treatment that are used to increase adhesion of coatings. Barrier coatings used for paper are mentioned, which improve properties like printability, smoothness, gloss, and brightness.
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The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
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Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
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China is seeing significant success in commerce, pipeline politics, and gaining influence on other
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The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
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1. PCB Surface Finishes: A General Review
By Jun Nable, Ph.D.
Introduction
Surface finishing is an integral part of any Printed Circuit Board (PCB) or Printed Wiring Boards (PWB)
fabrication. It is generally applied to exposed Cu connectors and conductors on the PCB. Surface finishing
has numerous important functions. It serves as a protective layer for the Cu connectors during storage.
The surface finish helps minimize or reduce tarnish of the Cu substrate. Additionally, since it is the
layer that comes into contact with other components during assembly, it ensures good solderability
between the PCB and the component during assembly. Furthermore after assembly, the finish helps
prolong the integrity of the solder joint during use.
What is a Surface Finish?
A surface finish is a material that is deposited onto the conductor surface of a PCB or PWB (Cu is the most
common conductor). It is typically a metal or an alloy but there are also surface finishes that are organic
polymer. Depending on the finish of choice , the deposition entails unique steps and
specialized equipment. Here we will review the most commonly used surface finishes in the industry.
Common Surface Finishes
This section discusses the most commonly used surface finishes in the PCB industry. Each has its own
unique features and processing challenges. There are other less common surface finishes such as
electrolytic, and even plasma, but we will limit the discussion to the list below.
1 Hot Air Solder Leveling (HASL)
2 Organic Solderability Preservative (OSP)
3 Immersion Tin (ImSn)
4 Immersion Silver (ImAg)
5 Electroless NickeljImmersion Gold (ENIG)
6 Electroless NickeljElectroless PdjImmersion Gold (ENEPIG)
As far as utilization of surface finishes , they are found in a wide range of applications. Ranging
from consumer electronics to more sophisticated high reliability electronics. The choice of a surface
finish will depend on balancing different factors such as performance, reliability and cost.
Figure 1 shows the 2014 surface finish market in terms of sold chemistry in millions of US dollars (1). The
largest share is by ENIG at about $210 million followed by OSP at $83 million. Immersion tin as a surface
finish is gaining wider use as it is being utilized more and more in automotive applications. The rest of the
surface finishes are much smaller with about $26 million each for immersion silver and HASL.
2. Surface Finish Market by sold chemistry
(m USD) ENIG
26.2 15.5
61.0
OSP
ImAg
ImSn
HASL
Others
26.0
210.0
82.5
Figure 1. Surface finish market in terms of sold chemistry (2014, in millions of USD)
Immersion Process
In general, a surface finish is directly deposited onto the Cu substrate surface. However, for
surface finishes that utilize an immersion approach such as immersion silver and immersion tin, the
deposit is applied via a displacement mechanism. It's worthwhile to differentiate an immersion process
from the conventional coating process. In a conventional coating process , the material of choice is
deposited via an additive approach. In other words , it is applied on top of the substrate surface.
Whereas in an immersion process , the material to be deposited is added at the expense of the
substrate surface. Figure 2 depicts a simple schematic of the immersion process wherein the deposit
(gray) is formed on the surface by displacing substrate material. This cycle keeps repeating itself until
there is no more accessible substrate material available to be displaced by the deposit material. Hence
immersion processes are considered self-limiting unlike autocatalytic process which could go on
indefinitely.
Figure 2. Schematic of an immersion process
Comparison of Surface Finishes
As mentioned above, the choice of surface finish depends on numerous factors. Each with its own
pros and cons. The next section will discuss and differentiate the common surface finishes used in the
industry.
3. Process Comparison
Table 1 illustrates the processing steps for the different surface finishes. The substrate preparation steps
are generally similar typically starting with a chemical cleaning of the PCB followed by microetching of the
Cu substrate. The initial cleaning step is often overlook but it is considerably important. The cleaner
prepares the board by removing grease , debris particulates and even soldermask residues on the
surface. Following the cleaner step is Cu etching. The microetch prepares the Cu substrate for the
desired morphology, and texture. Additionally providing further cleaning of the Cu surface.
Right after the substrate preparation steps are the specific chemical treatment steps depending on the
finish of choice. The processing times and cost varies for each and shown in the table for comparison
purposes.
Table 1. Processing comparison of the different PCB surface finishes
HASL OSP ImSn ImAg ENIG ENEPIG
Cleaner Cleaner Cleaner Cleaner Cleaner Cleaner
Rin
se
rin
se
rin
se
rin
se
rin
se
rin
se
Microetch Microetch Microetch Microetch Microetch Microetch
Rin
se
rin
se
rin
se
rin
se
rin
se
rin
se
Flux Pre-dip Pre-dip Pre-dip Catalyst Catalyst
Solder OSP Immersion Tin Immersion Silver rin
se
rin
se
AirKnife rin
se
rin
se
rin
se
Post-acid Post-acid
Cleaner rin
se
rin
se
Rin
se
Electroless Nickel Electroless Nickel
rin
se
rin
se
Immersion Gold Palladium
rin
se
rin
se
Immersion Gold
Rin
se
$ $ $$ $$ $$$ $$$$
� 10 to 15
min
� 25 to 30
min
� 15 to 20 min � 60 min � 65 to 75 min
Hot Air Solder Leveling
Hot air solder leveling or HASL for short, is one of the earlier type of finish still being used today.
It's relatively inexpensive and simple to apply. The PCB is dipped into molten solder and drawn up.
During this draw up, hot air knives would clean off any excess solder to leave behind only a thin layer.
The solder
4. Cu Cu Cu Cu
itself protects the underlying Cu conductorjconnector. Common HASL material include SnPb, SnCu
or even SnAgCu alloys.The thickness ofan HASL finish can vary from 0.2 to 50 um.
One of the best features of HASL is that it readily solders. After all , the Sn based alloy is the same
material used in soldering which allows for a good joint. This finish is also widely available. Furthermore
, it can be reworked by removing the solder finish. The downsides of HASL are its limited capability
for fine pitch dimensions. It's also not a flat finish which could complicate assembly. Its application
simplicity is also one of the drawbacks. Because it is dipped into molten solder, the entire PCB is
subjected to a very high temperature which is not good for the board material itself.
Organic Solderability Preservative
The only surface finish in this list that is not a metal or alloy is the Organic Solderability Preservative (OSP)
finish. The active compound is normally a thermally stable organic molecule based from a substituted
phenylimidazoles , or benzimidazoles and their derivatives. The OSP coating is formed when the
active molecule is allowed to network with Cu ions on the surface of the substrate. Figure 3 shows a
simple schematic of the OSP coating. The normal thickness of an OSP coating is from 0.1 to 0.3 um. Due
to the organic nature of this finish, it appears as a transparent colorless coating.
Cu Cu Cu Cu
N N N N
R R R R
N N N N
Cu Cu Cu Cu
N N N N
R R R R
N N N N
Cu
Figure 3. Schematic of an OSP coating
The application of an OSP coating is considerably inexpensive. It is simple to apply and easily reworkable
by stripping off the organic coating without much damage to the PCB. Another nice feature of the OSP is
that it yields a flat finish. Despite the nice qualities of OSP, it does have its own set of disadvantages.
The organic nature of this finish makes it more sensitive to handling issues (i.e. oils in fingers, etc). At the
same time, the organic molecule can withstand fewer number of thermal reflow cycles compared to
metallic finishes before it starts to deteriorate. This finish is also more challenging for inspection
because of its clear , transparent appearance. Furthermore , it's not electrically conductive so
electrical testing is not easily done.
5. Immersion Tin
As explained in the earlier section , immersion tin (ImmSn) is applied via a displacement
mechanism wherein the metallic Sn is deposited by replacing the surface Cu atoms on the PCB. The finish
itself is not a pure Sn metal but rather include traces of metal additive in the deposit. Thickness of
ImmSn can range from 0.8 to 1.2 um. However , the plating rate dramatically slows down at higher
thickness due to the self- limiting nature of the immersion process.
Immersion tin as a finish is gaining more market share due to growing adaptation particularly in the
automotive segments. It's not a cost prohibitive finish while giving fine pitch and flat plating capabilities.
This finish also exhibit excellent solderability. The one major disadvantage of ImmSn as a surface finish is
its susceptibility to tin whisker defect. This defect is the result of internal stress that developed in the
deposit. The only way to relieve this internal stress is that some material is 'pushed' out of the structure
hence forming very fine whiskers (see Figure 4). These whiskers grow outward and could eventually cause
shorting when it becomes dislodge or comes into contact with another adjacent connection. One way to
minimize is by incorporating metal additive to alter and reduce the internal stress. An additional challenge
for ImmSn is that most formulation contains thiourea which is a suspected carcinogen. So health
considerations should be taken when using this finish.
Figure 4. Tin whisker defect
Immersion Silver
Another immersion based surface finish is immersion silver (ImmAg). This process is also self-limiting,
with typical plating thickness in the range 0.1 to 0.4 um. The finish is about 99% Ag metal with small
traces of organic material. The coating is relatively simple and straight forward to apply.
Immersion silver exhibits very good solderability aside from depositing a flat finish. Furthermore it is useful
for fine pitch dimensions. Despite silver being a precious metal, the lower thickness target make it a
cost effective finish. The major disadvantage of ImmAg is it's propensity for corrosion attack from sulfur
and chloride bearing environment. As seen in Figure 5a, creep corrosion is one example of such
corrosion wherein at elevated humidity and temperature, the ImmAg finish will form metal sulfide
dendrites that can continue to grow and eventually cause shorting problems. To mitigate this problem
, a thin organic top coat can be applied to reduce the creep corrosion by providing an additional
barrier (Figure 5b).
6. a b
Figure S. (a) Creep corrosion on an Immersion silver finish (b) reduced corrosion when top coat is
applied
Electroless Nickel/Immersion Gold
The electroless nickeljimmersion gold (ENIG) finish has the largest market share among the surface finish
in terms of sold chemistry in USD. It's considerably more expensive than OSP and the immersion type
finishes. Not to mention that the steps are also longer and more complex since the finish comprise of two
distinct layers of metals: nickel and gold.
The electroless nickel (EN) layer is deposited via the autocatalytic mechanism. This approach utilizes a
chemical reducing agent to reduce the Ni ions in the plating bath. Depending on the formulation and type
of reducing agent; certain ingredients will also be co-deposited together with the Ni forming a Ni alloy.
Prior to Ni deposition, the Cu surface will need to be activated first. Activation is typically achieved
by catalyzing the surface with a precious metal to lower the activation energy for the chemical
reduction step. After Ni is deposited, gold is then plated via an immersion process. This time, the
gold is plated by replacing the Ni atoms in the EN layer. Figure 6 depicts an ENIG finish. The EN layer is
considerably thick with thickness from 3 to 6 um followed by a thin layer of ImmAu (i.e. 0.05 um).
Figure 6. An illustration of the ENIG surface finish
7. An ENIG finish has excellent solderability due to the good solubility of the gold layer with solder. This finish
has a very long shelf life as well because the gold has very good tarnish resistance. Besides the gold,
the EN layer is a good Cu diffusion barrier which helps allow for multiple reflow capabilities. The plating
also provides for a flat finish. Disadvantages of ENIG include increased cost and complexity of processing
owing to the 2 metallic layers. The EN processing requires a good understanding and proper control
of the operating parameters in order to obtain a good EN deposit. Otherwise , the EN layer can be
inferior and susceptible to issues such as corrosion attack , overplate and premature bath
decomposition. Plating mistakes with ENIG is almost impossible to rework. Stripping off the ENIG finish
will almost always result in some form of damage to the board surface. It's also worthwhile to point out
that most EN plating are done at elevated temperatures in the range of 80+ OC which is a high
enough temperature to cause problems with certain soldermask type. So a proper soldermask is needed
when plating with ENIG.
One majordisadvantage ofENIG isits susceptibilitytoblack pad corrosion (2).Thiscorrosion occurs during
the ENIG process more specifically during the deposition ofgold. Since gold is deposited via the immersion
mechanism , Ni atoms are displaced by the gold atoms being deposited. Ideally , the corrosion is
controlled and uniformly distributed along the entire EN surface. This would limit the corrosion to just a
top shallow layer. But in practice, black pad attack are localized corrosion wherein the attack on the
EN layer can extend throughout the entire thickness as seen in Figure 7. Black pad attack are more
commonly seen in irregular topography like deep crevices or grain boundary regions. These localized
corrosion spots are detrimental because they are much more concentrated resulting in significant
damage to the EN layer which would reduce the joint integrity leading to solder failure. It is also for
this reason that proper EN plating is paramount, otherwise an inferior EN foundation layer will be
obtained.
Figure 7. Black pad corrosion on ENIG
Electroless Nickel/Electroless Palladium/Immersion Gold
Electroless NickeljElectroless PalladiumjImmersion Gold or ENEPIG for short is one of the more durable
surface finishes. As the name implies , this coating utilizes 3 distinct metallic layers (see Figure 8).
Similar to ENIG, an EN layer serves as the foundation for this coating. Thickness for the EN layer is
between 3 to 6 um followed by a thin layer of electroless palladium (EPd) which can be between 0.2 to
0.5 um thick. The EPd layer is deposited with the use of a reducing agent so it's not achieved by
displacement reaction. Because the EPd is coated by using autocatalytic means, there is very minimal
damage to the EN layer since Ni is not displaced in order for Pd to deposit. Lastly, the top most layer
is the immersion gold. The gold layer in ENEPIG can be thinner than the gold layer in ENIG. In ENEPIG
finishes, the gold can be from
8. copper
substrate
• to 0.05 um thick. Since the gold layer is not in direct contact with the EN layer, the damage
from black pad corrosion is also much reduced and mitigated.
gold
palladium
nickel
Figure 8. An illustration of the ENEPIG surface finish
The ENEPIG finish is a very corrosion resistant surface finish allowing for a very long shelf life. It plates
considerably flat and is coplanar which makes it suitable for fine pitch dimensions. Among the surface
finishes, it is compatible with a wide variety of wire bond assembly methods not to mention it has
very good solderability as well. On the other hand, because of its multiple metallic layers, the process of
ENEPIG is much more complicated requiring the maintenance of 3 different plating chemistries (i.e. EN,
EPd, and ImmAu). This complexity would increase the processing cost further together with the cost
of using 2 precious metals (Pd and Au). This finish is also not easily reworked.
Summary
Surface finishes play several important roles in the electronics and PCB industry. Though there are
numerous different surface finishes available , each has its own unique advantages and
disadvantages. Hence it is important to correctly choose the appropriate surface finish that would meet
the requirements of the targeted application.
References:
• Mustafa Oezkoek, Hubertus Mertens, and Maren Bruder, SMTA International
Conference Proceedings, September 2014
• Kejun Zeng, Roger Stierman, Don Abbott, Masood Murtuza, Journal of the Minerals,
Metals and Materials Society, Vol. 58 (6), June 2006