LTCC Overview


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a review on status of multilayer low temperature cofired ceramcis technology

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LTCC Overview

  1. 1. LTCC Passive Integration Status and challenges Steve Dai, Motorola Labs, Tempe, Arizona Channel/ cavity Embedded Capacitor
  2. 2. Outline • Introduction • LTCC (Low Temperature Cofired Ceramics) – LTCC materials – LTCC Passive integration – LTCC feature forming – Zero shrink tape: ideal way for integration? • LTCC Applications – Wireless – Automotive, energy and others • Summary Steve Dai, SICCAS LTCC Seminar 7_16_2007
  3. 3. Introduction Why Passive Integration? • Device miniaturization • Greater component density for increased functionality • High speed signal process requires – Lower equivalent series inductors – Tighter control of parasitic R, C and L • Higher assembly yield • Lower system cost • Better reliability * Robert Heistand, ED Online #2718, Feb 2, 2003 Steve Dai, SICCAS LTCC Seminar 7_16_2007
  4. 4. Introduction Paths to Passive Integration – technologies Characteristics PCB (Printing LTCC Thin film on Circuit Board, (MCM-C) Si/glass MCM-L) (MCM-D) Substrates FR-4, BT, FR-5 Ceramic Si, Glass, Sapphire Dielectric Constant (εr) 4.9 / 3.9 / 4.7 7 -12 12 / 5 / 10 Loss Tangent (1 GHz) .015 /.009/.010 .0003 -.003 .005/ .003 / .0001 Thermal σ(W / m-K) .2 -.4 2.5 100 / 1.7 / 42 CTE (ppm) 15 / 15 / 13 6 2.6 / 1 / 8 # of Layers 8 30 6 Conductors Cu Ag, Ag/Pd, Au, Pt, Cu Al, Cu, Au Electrical ρ (10-8 Ω-m) 1.7 1.2~1.7 2.6 / 1.7 / 2.1 Thermal ρ (W/m-K) 398 398~428 247~398 Line Width (μm) 100 75 5 Process Variation 10 -15 % 2 –4 % 2 –4 % RF Frequency < 10 GHz <25 GHz < 50 GHz # Iterations to Spec 5 5 5 Iteration Time 1 week 2 weeks 2-4 weeks Iteration Cost1 $.5 K $2 K $10 K * From INEMI Steve Dai, SICCAS LTCC Seminar 7_16_2007
  5. 5. Introduction Paths to Passive Integration – a comparison Technology Integration Advantages Disadvantage method Thin film on Lithographically defined L/C/R Precision L/C/R value Low inductance High tolerance Equipment costly Si/glass Sequential build up of High component density Limited selection on film layers (MCM-D) Cost effective for dies < materials 20 mm2 Materials compatibility Thick film on Screen printed L/C/R on sintered ceramic Low cost process No precise Rs High packaging density Ls difficult to form ceramics substrates (e.g. Al2O3) Module reliability - auto Process time and yield Sequential build up of (MCM-C) multiple layers applications due to sequential buildup PCB (Printing Discrete L/C/R buried in laminated structure Low cost process Lack high K dielectric Multilayer structure R limited, trimming Circuit Board, Sequential or parallel Cu conductor PCB not RF friendly MCM-L) process No CAD tool for PCB passive layout LTCC Screen printed L/C/R on “green” ceramics tapes Parallel layer process Cofireability of materials High layer counts~ 100 No high K dielectric (MCM-C) Parallel multi layer and RF friendly materials No precise Rs final cofired structure Module reliability Inductor limited * Robert Heistand, ED Online #2718, Feb 2, 2003 Steve Dai, SICCAS LTCC Seminar 7_16_2007
  6. 6. Introduction LTCC market potential * From Paumonok, in millions of US$ LTCC market driven by RF wireless applications – Loss conductors, Ag – Temperature stable base dielectric, Tf ~ 0 ppm/°C – Precision stack capacitor – resonator – Fast turn around – Infrastructure – Competitive cost Steve Dai, SICCAS LTCC Seminar 7_16_2007
  7. 7. Introduction LTCC landscape US/CA EU JP Asia - other Epcos, Selmic, TAHLES, VIT, IMST Soshin/NGK, Taiya Yuden, Nikko LTCC Motorola ACX (TW), Samsung EMCO, Nippon Electro Glass, etc Applications Northrop Grumman Rockwell TDK LTCC Ford/GM Bosch, Siemens Hitachi, MuRata Design LTCC C-MAC, CTS Vispro, ATC Foundries CoorsTec LTCC DuPont, Ferro materials Hereaus, ESL Horizontal Vertical Steve Dai, SICCAS LTCC Seminar 7_16_2007
  8. 8. LTCC Process Flow Steve Dai, SICCAS LTCC Seminar 7_16_2007
  9. 9. Common LTCC Base Dielectrics Steve Dai, SICCAS LTCC Seminar 7_16_2007
  10. 10. LTCC Base Dielectric a comparison Green Sintered Type 1: Unreactive, glass as bonding agent Example: DuPont 951 Type 2: Re-crystallizeable, glass re- crystallize to form high Q phases Example: Ferro A6 Type 3: Reactive, glass as both bonding agent and ingredients for high Q crystalline phases Example: Motorola T2000 Glass Al2O3 Crystalline phase Steve Dai, SICCAS LTCC Seminar 7_16_2007
  11. 11. Motorola T2000 LTCC Dielectric Existing system: Glass: K2O, B2O3, SiO2 Ceramic Filler Tf K=7.8 CaO, SrO, BaO Al2O3 Adjuster TiO2 Q=500 Tf=-60 ppm/°C Contains Pb Sintering 850~ 900 °C Residual CaAl2Si2O8, Q=1300 Al2O3 T2000 dielectric: Glass SrAl2Si2O8, Q=1300-10000 Q = 10000 K=9.1 Q ~ 350 BaAl2Si2O8, Q=10000 VAl2O3 TiO2 Q=1000 Vglass Vcryst. Tf~ 0 ppm/°C Pb-free Dielectric 1= V Vglass Vcryst . V i≈ + + Al 2O 3 Mixture Q ∑Q 350 1500 10000 i Calculated Q: ~ 1100, measured Q: 1050 - 1200 Steve Dai, SICCASA, 7/18/2007
  12. 12. T2000 TEM Microstructure Al2O3 particles from 3 μm to <1 μm High Q phases formed in reaction Al2O3 dissolves/diffuses into glass Particle size/S.A. Sintering T and t Heating rate Steve Dai, SICCAS LTCC Seminar 7_16_2007
  13. 13. T2000 Temperature Stability 1.006 T f Measurement 1.248 Tf Measurement 1.246 TiO 2 added 1.004 Resonant frequency (10 9 Hz) No TiO 2 1.244 Normalized Frequency 1.002 1.242 1.000 1.24 1.238 T f =4.2 ppm/°C 0.998 T2000: 0.6 ppm/C 1.236 FerroA6: -48 ppm/C T f =-78.5 ppm/°C DuPont 943: -58 ppm/C 1.234 0.996 DuPont 951: -69 ppm/C Hereaus: -76 ppm/C 1.232 -40 -20 0 20 40 60 80 0.994 Temperature (°C) -50 -30 -10 10 30 50 70 90 Temperature (C) Compensation of Tf (temp coef of resonant freq): Need negative Tk material, TiO2 (TK =-750 ppm/°C) Tf= -(1/2)Tk - α, α is thermal coefficient of expansion Tf of T2000 is -80 ppm/°C without compensation Can be continuously tuned near 0 ppm/°C Steve Dai, SICCAS LTCC Seminar 7_16_2007
  14. 14. T2000 TiO2 Distribution T2000 Quantitative Analysis: (wt%) wTiO2 wAl2O3 wCaF2 Ref 1 0 100 20 Ref 2 30 70 20 Ref 3 60 40 20 Ref 4 100 0 20 Sintered T2000 3.5 40.3 20 Unfired T2000 6.2 49.1 20 Steve Dai, SICCAS LTCC Seminar 7_16_2007
  15. 15. LTCC Passive Integration Embedded high K dielectrics BZN Cofired in LTCC BZN high K dielectric Ag Dielectric properties of low fire BZN K80 T2000 “Higher K Low Loss Dielectric Ceramic Cofireable with a Commercial LTCC Tape System”, Weiming Zhang, J. Thomas Hochheomer, Christina Modes, Peter Barnwell and Steve Dai, IMAPS annual meeting, Oct. 2001, Baltimore, USA. To be published on IMAPS proceedings. 10 μm Critical: Lower sintering from 1050 to 850 C with 0.5~3.0 wt% glass Steve Dai, SICCAS LTCC Seminar 7_16_2007
  16. 16. LTCC Conductors Common conductors and Ag/Pd paste 20 15 Observation Dimentional Change (%) 10 • Glassy sintered surface 5 with mixed Ag/Pd 0 conductor -5 Dieletric • No surface glass -10 Ag/Pd alloy Ag/Pd mixture observed with alloy -15 * courtesy T. Garino - Sandia National Labs, Albuquerque, NM Ag/Pd -20 300 350 400 450 500 550 600 650 700 750 800 850 900 950 Temperaure (°C) Ag: 962 ºC Pd: 1772 ºC Unusual large expansion in Ag/Pd mixture in 350-400 ºC. Kirkendall Effect? Steve Dai, SICCAS LTCC Seminar 7_16_2007
  17. 17. LTCC Passive Integration Embedded resistor RuO2 based Screen Direct embedded resistor print write to Dielectric properties of low fire BZN t P. Yang, D. Dimos, M. A. Rodriguez, R. F. Huang, S. Dai, D. Wilcox., MRS Proc 542 (1999) Steve Dai, SICCAS LTCC Seminar 7_16_2007
  18. 18. LTCC Passive Integration Embedded resistor in via Steve Dai, SICCAS LTCC Seminar 7_16_2007 (Courtesy of F. Uribe et al., Sandia)
  19. 19. LTCC Passive Integration integrated magnetic materials HeraLock with cofired ferrite A. Feingold, et al., IMAPS 2001 transformer, F. Lautenhiser and E. Amaya, ICAPS 2002 Steve Dai, SICCAS LTCC Seminar 7_16_2007
  20. 20. LTCC Integration piezoelectric/piezoresistive Materials PZT/LTCC membrane, W. Hermel, P. Otschik, A. Schonecker, Fraunhofer IKTS, Dresden Piezoresistive pressure sensor on LTCC membrane for integrated pressure LTCC. Sensitivity: 1.3 mV/kPa sensor, L Golonka, Wroclaw University Steve Dai, SICCAS LTCC Seminar 7_16_2007
  21. 21. LTCC Passive Integration Status Embedded L Embedded C Cofired R (5 ~ 200 nH) Paste Layer Embedded Surface (up to 25 (50~70 (10 Ω/sq ~ trimmable nf/cm2 with pf/cm2) 100 kΩ/sq) (10 Ω/sq ~ 1 K800) MΩ/sq) ± 5% ± 30% ± 5% ± 30% ± 2% Steve Dai, SICCAS LTCC Seminar 7_16_2007
  22. 22. LTCC Feature Forming Critical sizes Steve Dai, SICCAS LTCC Seminar 7_16_2007
  23. 23. LTCC Feature Forming techniques Steve Dai, SICCAS LTCC Seminar 7_16_2007
  24. 24. LTCC Feature Forming microchannels Sintering cavity without fugitive material M. R. Gongora-Rubio et al.,Sensors and Actuators (2001) Compensate sagging with supported structure Integrated UV Light Source Controlled firing of fugitive carbon black paste Dia. =150 μm V Thickness = 110 μm Gas: Ne G. Eden, B. Vojak, Univ. of V = 100- 200 V Illinois, Urbana, Illinois, (Courtesy of T. Garino, Sandia) I = 2 mA Steve Dai, SICCAS LTCC Seminar 7_16_2007 Pressure = 200-800 Torr
  25. 25. LTCC Feature Forming suspended structure Antennae Suspended Inductors 1 mm Unfired 1 mm Fired K. A. Peterson et al., CICMT (2005) Steve Dai, SICCAS LTCC Seminar 7_16_2007
  26. 26. LTCC Feature Forming released moving parts Pneumatically driven functional-as- released wheels (3 mm) Setter as fugitive materials K. A. Peterson et al., CICMT (2005) Wheel free to rotate Steve Dai, SICCAS LTCC Seminar 7_16_2007
  27. 27. LTCC Feature Forming Unconventional Forming and Physical Insertion Ion Mobility Spectrometer Heated gas feed tube Rolled IMS drift tube 1 cm Thermistor Contact buried heater 12 mm I.D. K. A. Peterson et al., CICMT (2005) (Courtesy of K. A. Peterson and K. B. Pfeifer, Sandia) Steve Dai, SICCAS LTCC Seminar 7_16_2007
  28. 28. Zero-shrink LTCC Tape transfer tape Al2O3 tape Al2O3 tape Al2O3 LTCC Module Sinter LTCC Module LTCC Module removal Al2O3 tape Al2O3 tape Compatible lamination process Limited LTCC layers Require backend Al2O3 removal from surface Post fire surface electrode patterns Steve Dai, SICCAS LTCC Seminar 7_16_2007
  29. 29. Zero-shrink LTCC Tape differentiate shrinkage By W. Wersing et al., Siemens Steve Dai, SICCAS LTCC Seminar 7_16_2007
  30. 30. Zero-shrink LTCC Tape Heralock HL2000 (courtesy of Hereaus) Full ground plane Needs no extra processing Virtually zero x & y shrinkage Very precise dimensional control Fires flat Cavities readily available Allows novel structures Steve Dai, SICCAS LTCC Seminar 7_16_2007
  31. 31. LTCC Applications RF building blocks ANT C7 C8 Z1 Multilayer Capacitor Z4 C1 Z2 D1 Z3 C4 TX RX Vertically Coiled C2 C3 D2 C5 Transmission Line BIAS C6 Metal Dielectric Paste Metal Horizontally Coiled Dielectric Tape Transmission Line Dielectric Paste Capacitor Steve Dai, SICCAS LTCC Seminar 7_16_2007
  32. 32. LTCC Applications RF frontend modules Steve Dai, SICCAS LTCC Seminar 7_16_2007
  33. 33. LTCC Applications Wireless modules IMST radar sensor IMST transceiver module RF moduels, Micro Systems Kyocera PA module – size reduction via passive Engineering GmbH integration Steve Dai, SICCAS LTCC Seminar 7_16_2007
  34. 34. LTCC Applications automotive – slow yet stable growth Bosch electronic turbo charger • working temperature up to 155°C • high vibration stress up to 50g • direct engine mountability • high packaging density (Thick Film -> LTCC) Delphi Delco LTCC ABS controller Delphi Delco LTCC ECU Steve Dai, SICCAS LTCC Seminar 7_16_2007
  35. 35. LTCC Applications Direct Methanol Fuel cell Concept for Fuel Cell with integrated pumping and control Gold Flow Field Current Air Holes (anode side) Collector (cathode side) Working Fuel Cell Steve Dai, SICCAS LTCC Seminar 7_16_2007 Assembled Fuel Cell
  36. 36. LTCC Applications Micro cooling Heat pipes Heat spreader layout of microchannels grey: line + printed resistor, black: cooling channel) Microchannel cooling Heat pipes formed with LTCC micro channels as heat spreader (Kinzy Jones, FIU) (H. Thust, Ilmenau TU) Steve Dai, SICCAS LTCC Seminar 7_16_2007
  37. 37. LTCC Applications Optoelectronic packaging WAVEGUIDE Demodulator IC Input/Output Integrated laser and optical modulator ELECTRICAL Input/Output Embedded optical Photo detector switches Coax cable Polyme r optical waveguide embedded in LTCC LTCC Fibre alignment groove Ball grid array mounting Transimpedance amplifier (flip chip) Photo detector array MEMS package with integrated Embedded passives heaters and thermistors (L. Silicon V-groove (resistors/capacitors) Golonka, Wroclaw U.) Multilayer LTCC Fibre Optic Input/Output substrate CMAC’s System In a Package Vision Steve Dai, SICCAS LTCC Seminar 7_16_2007
  38. 38. Summary LTCC is powerful platform integration technology with wide applications Wireless applications is the fastest growth area Material challenges: Base and integrated high K Dielectrics Improved Conductors (Au, Ag, Ag/Pd, Pt, Cu, etc) Precision cofired resistors Magnetic materials Functional materials (Ferroelectric, piezoelectric, magnetic, sensing, …) Process Challenges Combination of tape and thick film processes Thin film process for fine feature forming Interconnect technologies Modeling on sintering of dissimilar materials Integration and Assembly Challenges Application driven Technologically innovative Knowledge-based understanding Steve Dai, SICCAS LTCC Seminar 7_16_2007
  39. 39. Backup slides Methanol Reformer Cell Phone Receiver 15 mm fuel integrated ENERGY reformers modules 5 mm MICROSYSTEM WIRELESS Direct FUNCTIONS on-chip COMMUNICATIONS Methanol power Fuel Cell ICs amplifiers sensors fuel NEW Micro Hollow Cathode cells MATERIALS & filters 8 mm Discharge (MHCD) PROCESSES light pumps UV light source sources 8.5 mm Power Amplifier temperature chemical reactors PCR E-chip control Pumping/ Mixing V cell sorting Integrated BioChip Technology LIFE DNA Steve Dai, SICCAS LTCC Seminar 7_16_2007 SCIENCES amplification
  40. 40. Backup slides ~ ~ LNA Bypass Impedance Power and Bias Capacitors Bandpass Filter Matching Line To Bias Amplifier Circuit Trap From Filter Amplifier 1 cm X 1 cm Switch w/ Harmonic 41 components/sq. cm Filter To Mixer Switch Image Reject Filter Transmit Antenna Bias Steve Dai, SICCAS LTCC Seminar 7_16_2007