The document describes a project to develop a fabrication process for tungsten silicon nitride (WSiN) thin film resistors with very high sheet resistance (TFRVHs) for use in monolithic microwave integrated circuits. The design approach involves using reactive sputtering deposition with a WSi3 target and introducing nitrogen gas to increase the sheet resistance of deposited WSiN films. Various characterization tools are identified to evaluate the sheet resistance, thickness, stress, morphology, and composition of deposited films to determine if the design requirements are met. The goals are to produce TFRVHs with 2000 ohm/square sheet resistance, 750-1500 angstrom thickness, and within 10% standard deviation, uniformity and margin of error.
Different types of Nanolithography technique.
Types: Electron beam lithography, Photolithography, electron-beam writing, ion- lithography, X-ray lithography, and related images, concepts and graphical views.
I hope this presentation helpful for you.
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In this presentation,
The author gives the working principle of the PVD and Sputtering methods. But you can also find an information about the thin film and plasma phase of a matter.
Also this is related with Magnetron Sputtering method.
Different types of Nanolithography technique.
Types: Electron beam lithography, Photolithography, electron-beam writing, ion- lithography, X-ray lithography, and related images, concepts and graphical views.
I hope this presentation helpful for you.
https://www.linkedin.com/in/preeti-choudhary-266414182/
https://www.instagram.com/chaudharypreeti1997/
https://www.facebook.com/profile.php?id=100013419194533
https://twitter.com/preetic27018281
Please like, share, comment and follow.
stay connected
If any query then contact:
chaudharypreeti1997@gmail.com
Thanking-You
Preeti Choudhary
If you have any questions, contact me. I would be happy to help.
PLEASE LIKE IT AND GIVE COMMENT
In this presentation,
The author gives the working principle of the PVD and Sputtering methods. But you can also find an information about the thin film and plasma phase of a matter.
Also this is related with Magnetron Sputtering method.
This to demonstrate the laser ablation of hard materials to form a thin film for optical sensors. The work was done at DIllard University , New Orleans LA by Professor Abdalla Darwish. any comment e-mail adarwish@bellsouth.net.
Electron beam lithography (often abbreviated as e-beam lithography or EBL) is the process of transferring a pattern onto the surface of a substrate by first scanning a thin layer of organic film (called resist) on the surface by a tightly focused and precisely controlled electron beam (exposure) and then selectively removing the exposed or nonexposed regions of the resist in a solvent (developing). The process allows patterning of very small features, often with the dimensions of submicrometer down to a few nanometers, either covering the selected areas of the surface by the resist or exposing otherwise resist-covered areas. The exposed areas could be further processed for etching or thin-film deposition while the covered parts are protected during these processes. The advantage of e-beam lithography stems from the shorter wavelength of accelerated electrons compared to the wavelength of ultraviolet (UV) light used in photolithography.
In EBL, a resist layer is directly patterned by scanning with an electron beam electronically. Modern EBL systems have very good depth of focus (several hundred nanometres) and are able to correct for large-scale height variations of the wafer (of several hundred microns), and so are able to cope well with the rough surface topology of typical GaN wafers and associated wafer bow. EBL also has the advantage of allowing multiple designs to be fabricated together on one wafer. EBL is, however, a slow and expensive process, which is not practical for production. Substrate charging and proximity error effects must be taken into account to get good quality devices. Charging effects can be overcome by application of a sub-nanoscale removable conductive layer on top of the resist. Proximity error correction effects are overcome using specialised design correction software.
Alban sublet niobium coated hie-isolde qwr superconducting accelerating cav...thinfilmsworkshop
The new HIE-ISOLDE accelerator at CERN requires the production of 32 superconducting cavities (20 high-beta and 12 low-beta) in order to increase the energy of the rare isotope beam delivered to the experiments. The Quarter Wave Resonators (QWRs) cavities (0.3m diameter and 0.8m height) are made of OFE 3D-forged copper and are coated by DC-bias diode sputtering with a superconducting niobium thin film. The series production of the high-beta cavities has started. In parallel to the production, a systematic characterization of the film has been launched. Thickness measurement, RRR and FIB-SEM cross section and TEM analysis are conducted in collaboration with EPFL (CIME) to investigate the film growth and its morphological properties at different places along the cavity inner and outer conductor. Samples are produced in a test cavity with the baseline production coating recipe and in the same hardware to be as close as possible to the production conditions.
The production coating cycle and setup to match the HIE-ISOLDE specifications (operation at 4.5 K with an accelerating field of 6 MV/m at 10W RF losses and Q0=4.5x108) is described and the resulting niobium film characteristics is presented.
Improvement of Surface Roughness of Nickel Alloy Specimen by Removing Recast ...IJMER
Abstract: In this investigation, experimental work and computational work are combined to obtain improvement in the surface roughness of nickel alloy specimen, the machining is carried out by means of CNC wire electric discharge machining (WEDM). Brass wire is used as the tool electrode and nickel alloy (Inconel600) is used as the work piece material. The machining parameters such as Pulse-On time (Ton), Pulse-Off time (Toff), Peak Current (Ip), and Bed speed are considered as input parameters for this project. Surface roughness and Recast layer are considered the output parameters. The experiments
with the pre-planned set of input parameters are designed based on Taguchi’s orthogonal array. The surface roughness is measured using stylus type roughness tester and the thickness of the Recast layer is measured using Scanning Electron Microscope (SEM). The results obtained from the experiments are fed to the Minitab software and optimum input parameters for the desired output parameters are identified. The software uses the concept of analysis of variance (ANOVA) and indicates the nature of effect of input parameters on the output parameters and confirmation is done by validation
experiments. Once the recast layer thickness is obtained Chemical Etching and abrasive blasting is performed in order to remove the recast layer and again the surface roughness is measured by using stylus type roughness tester. Finally from the obtained results it was found that there was significant improvement in the Surface roughness of the nickel alloy material. In addition using regression analysis this work is stimulated by computational method and the results are obtained
This to demonstrate the laser ablation of hard materials to form a thin film for optical sensors. The work was done at DIllard University , New Orleans LA by Professor Abdalla Darwish. any comment e-mail adarwish@bellsouth.net.
Electron beam lithography (often abbreviated as e-beam lithography or EBL) is the process of transferring a pattern onto the surface of a substrate by first scanning a thin layer of organic film (called resist) on the surface by a tightly focused and precisely controlled electron beam (exposure) and then selectively removing the exposed or nonexposed regions of the resist in a solvent (developing). The process allows patterning of very small features, often with the dimensions of submicrometer down to a few nanometers, either covering the selected areas of the surface by the resist or exposing otherwise resist-covered areas. The exposed areas could be further processed for etching or thin-film deposition while the covered parts are protected during these processes. The advantage of e-beam lithography stems from the shorter wavelength of accelerated electrons compared to the wavelength of ultraviolet (UV) light used in photolithography.
In EBL, a resist layer is directly patterned by scanning with an electron beam electronically. Modern EBL systems have very good depth of focus (several hundred nanometres) and are able to correct for large-scale height variations of the wafer (of several hundred microns), and so are able to cope well with the rough surface topology of typical GaN wafers and associated wafer bow. EBL also has the advantage of allowing multiple designs to be fabricated together on one wafer. EBL is, however, a slow and expensive process, which is not practical for production. Substrate charging and proximity error effects must be taken into account to get good quality devices. Charging effects can be overcome by application of a sub-nanoscale removable conductive layer on top of the resist. Proximity error correction effects are overcome using specialised design correction software.
Alban sublet niobium coated hie-isolde qwr superconducting accelerating cav...thinfilmsworkshop
The new HIE-ISOLDE accelerator at CERN requires the production of 32 superconducting cavities (20 high-beta and 12 low-beta) in order to increase the energy of the rare isotope beam delivered to the experiments. The Quarter Wave Resonators (QWRs) cavities (0.3m diameter and 0.8m height) are made of OFE 3D-forged copper and are coated by DC-bias diode sputtering with a superconducting niobium thin film. The series production of the high-beta cavities has started. In parallel to the production, a systematic characterization of the film has been launched. Thickness measurement, RRR and FIB-SEM cross section and TEM analysis are conducted in collaboration with EPFL (CIME) to investigate the film growth and its morphological properties at different places along the cavity inner and outer conductor. Samples are produced in a test cavity with the baseline production coating recipe and in the same hardware to be as close as possible to the production conditions.
The production coating cycle and setup to match the HIE-ISOLDE specifications (operation at 4.5 K with an accelerating field of 6 MV/m at 10W RF losses and Q0=4.5x108) is described and the resulting niobium film characteristics is presented.
Improvement of Surface Roughness of Nickel Alloy Specimen by Removing Recast ...IJMER
Abstract: In this investigation, experimental work and computational work are combined to obtain improvement in the surface roughness of nickel alloy specimen, the machining is carried out by means of CNC wire electric discharge machining (WEDM). Brass wire is used as the tool electrode and nickel alloy (Inconel600) is used as the work piece material. The machining parameters such as Pulse-On time (Ton), Pulse-Off time (Toff), Peak Current (Ip), and Bed speed are considered as input parameters for this project. Surface roughness and Recast layer are considered the output parameters. The experiments
with the pre-planned set of input parameters are designed based on Taguchi’s orthogonal array. The surface roughness is measured using stylus type roughness tester and the thickness of the Recast layer is measured using Scanning Electron Microscope (SEM). The results obtained from the experiments are fed to the Minitab software and optimum input parameters for the desired output parameters are identified. The software uses the concept of analysis of variance (ANOVA) and indicates the nature of effect of input parameters on the output parameters and confirmation is done by validation
experiments. Once the recast layer thickness is obtained Chemical Etching and abrasive blasting is performed in order to remove the recast layer and again the surface roughness is measured by using stylus type roughness tester. Finally from the obtained results it was found that there was significant improvement in the Surface roughness of the nickel alloy material. In addition using regression analysis this work is stimulated by computational method and the results are obtained
A memory stack on logic 3D IC stack was considered for comparative study of warpage response to two different process choices, namely, Die to Die (D2D) and Package to Die (P2D) assembly. Process and reliability modeling software CielMech, and Commercial Finite Element Analysis (FEA) software ANSYS Mechanical were utilized to simulate thermo-mechanical effects of sequential chip attach, underfilling and encapsulation process steps for the chosen flows. Warpage at room temperature as well as attach temperature after each attach step were compared. Results indicated that underfill, substrate, and mold compound thermal strains play important roles in warpage evolution. Significant differences in the final assembled state warpage was predicted and is attributable to path dependence of warpage evolution.
Improvement of Surface Roughness of Nickel Alloy Specimen by Removing Recast ...IJMER
In this investigation, experimental work and computational work are combined to obtain
improvement in the surface roughness of nickel alloy specimen, the machining is carried out by means
of CNC wire electric discharge machining (WEDM). Brass wire is used as the tool electrode and nickel
alloy (Inconel600) is used as the work piece material. The machining parameters such as Pulse-On time
(Ton), Pulse-Off time (Toff), Peak Current (Ip), and Bed speed are considered as input parameters for this
project. Surface roughness and Recast layer are considered the output parameters. The experiments
with the pre-planned set of input parameters are designed based on Taguchi’s orthogonal array. The
surface roughness is measured using stylus type roughness tester and the thickness of the Recast layer
is measured using Scanning Electron Microscope (SEM). The results obtained from the experiments are
fed to the Minitab software and optimum input parameters for the desired output parameters are
identified. The software uses the concept of analysis of variance (ANOVA) and indicates the nature of
effect of input parameters on the output parameters and confirmation is done by validation
experiments. Once the recast layer thickness is obtained Chemical Etching and abrasive blasting is
performed in order to remove the recast layer and again the surface roughness is measured by using
stylus type roughness tester. Finally from the obtained results it was found that there was significant
improvement in the Surface roughness of the nickel alloy material. In addition using regression
analysis this work is stimulated by computational method and the results are obtained.
1. Reactive Sputtering to Increase
Sheet Resistance of WSiN Thin
Films
Raymond Chen, Antonio Cruz, Jack Lam, Niteesh Marathe, Camron Noorzad, Yongsheng Sun,
Cheng Lun Wu, Disheng Zheng
2. Outline
1. Problem Identification
2. Design Approach
3. Evaluation
4. Conclusion and
Recommendations
A. Project Background
B. Problem Scope
C. Technical Review
D. Design Requirements
3. Project Motivation
• Keysight Technologies has interest of expanding into new markets:
1. Develop new platforms
2. MMIC (High-frequency monolithic microwave integrated circuit)
3. TFRVH (thin film resistor very high)
4. Students Research and Development
5. Sell products and make profit
6. Project Goals
• Develop a fabrication process for WSiN TFRVHs:
1. Produce TFRVHs with desired specifications:
• 2000 Ω/sq sheet resistance
• 750 Å ~1500 Å thickness
• 10% Standard Deviation and Uniformity
2. Demonstrate our results were consistent and repeatable
7. Problem Scope
● Concern of produce TFRVHs on Silicon Wafer
○ Use appropriate deposition method
○ Determine parameter input
○ Achieve priority specification
○ Maintain consistent output
http://project-planners.com/wp-
content/uploads/the_project_triangle1.jpg
8. Technical Review: Reactive Sputtering
• Method of introducing reactive gas into
sputtering to fabricate thin film resistor
• Easy to control deposition properties
• PVD
• Target is bombarded by energetic ions, In
this case Argon ions (Ar⁺)
• Collisions knock and sputter atoms from
the target
• Sputtered atoms flow to be deposited
onto the substrate
magnets
http://ns.kopt.co.jp/English/ca_jou-gi/joutyaku.htm
9. Technical Review: Advantages of Sputtering
• Wide range of possible sputtered materials
• High deposition rates
• High purity thin films (vacuum, low pressure)
• Good adhesion
• Good step coverage and uniformity
• Allow various parameter control
• Available in both DC and RF power
• Magnetron sputtering uses magnets behind
target to attract electrons to facilitate electron-
Argon collision
http://dir.indiamart.com/impcat/sputtering-systems.
html
10. Technical Review: Disadvantages of Sputtering
● Deterioration of equipment and target material
○ High sheet resistance uniformity percentage
■ Bad yield percentage
● Possible sputter gas incorporation into film
11. Technical Review: Why we use RF power
● Power oscillated at radio frequencies sustains the Argon plasma
○ If not. The negative charge applied to target can be neutralized by Ar⁺
○ Ions will not be attracted to target
● Ions are too heavy and slow to follow this frequency
● Electrons can follow this frequency and build up a negative self bias on the
target
12. Technical Review: Why Ar⁺
● Big gas ion
● Inert to WSiN
● Produce high sputtering yield
○ manufacturing process to be
timely and efficient
● Relatively inexpensive and
available in high purity
Source: [9]
13. Technical Review: Tungsten Silicon Nitride
● Ability to reduce the local atomic ordering when sputtered due to argon ion
bombardment
● High melting point of around 3000 o
C
● Applications:
○ Lower power consumption of a capacitive touch screen
○ Mask material for x-ray lithography
○ Hard coating
○ Printer heads
14. Technical Review: Target Processing
● Composite from hot pressing
Tungsten powder and Silicon
Nitride powder
● Because of this, we suspect that
the sputter result will be silicon
nitride and tungsten.
15. Technical Review: Substrate and Chamber
● Silicon substrate (100) orientation with approximately 100 nm silicon dioxide on
top
○ Negative substrate bias: -60 V
■ Better guidance of WSiN movement to substrate and substrate
adhesion, increasing nitrogen content
○ Low cost substrate for experimental purpose
○ One patterned + one non-patterned
● Real substrate will be GaAs and InP
● High vacuum chamber: 10 mTorr
○ lower sputter rate
○ increase the mean free path of sputtered target
16. Technical Review: WSiN Thin Film
● Would cause crystallization and loss of nitrogen content around 800o
C
● Nitrogen atoms bonded to silicon atoms of the Tungsten and Silicon
Amorphous Network increase the resistivity
● Coefficient of thermal expansion of WSiN is 6.37 X 10^-6 °C−1,
○ The coefficient of thermal expansion of Si is 3.45 × 10−6 °C−1
○ This difference can result in significant thermal stresses if the Si
substrate is heated during deposition.
● Amorphously deposited on the substrate
● Very effective at blocking atom diffusion
● Chemical Inertness
17. Technical Review: Sheet Resistance
● Measure of resistance for thin film materials
instead of a bulk material
● Sheet resistance is defined as: Rs
=(⍴/t)
○ ⍴ is material’s resistivity and t is
thickness
● Has unit of ohm but usually use
“ohm/square”
● Only need to specify length and width of the
resistor to define value.
● The ratio L/W represents the number of unit
squares of material in the resistor
18. Outline
1. Problem Identification
2. Process Design
3. Evaluation
4. Conclusion and Recommendations
A. Design Requirement
a. Input Parameter
b. Output Parameter
B. Design Approach
a. Sputtering System
b. Substrate Bias
c. Justification of N2
gas flow
d. Deposition Time
e. Film Stress
f. Thickness
g. Four-Point Probe
19. Design Requirements
Sputtering Input Parameters
Fixed Parameters
RF Power 750 W
Substrate Bias -60 V
Total System Pressure 10 mTorr
Total Flow Rate 40 sccm
Controlled Parameters
Gas Ratio (N2
: Ar) 0.15 : 1
N2
Flow Rate 5.2 sccm
Ar Flow Rate 34.8 sccm
Deposition Time 1027 Seconds
Target Thin Film Parameters
Sheet Resistance 2000 ohm/square
Margin of Error ±3%
Standard Deviation ±10%
Uniformity ±10%
Thickness (x) 750 Å < x <1500 Å
21. Design Approach
● CVC 611 Reactive Sputtering System
○ Older machine in the wafer fab
○ Ion mill chamber to clean wafer before
deposition process [4]
○ Rotating deposition to increase sheet
resistance uniformity [4]
● Sputtering Target: WSi3
N4
Front monitor and chamber
of CVC 611 System.
Source: [4]
Back of CVC 611 System with
the RF Power Supply. Source: [4]
22. Design Approach
Substrate Bias
• Negative bias allows for Ar⁺ ion
bombardment onto substrate, minimizes
long range atomic order
(amorphous thin film) [4]
• Bias repels electrons from depositing onto
the film [4]
• Standard value for the CVC System in the
wafer fab [4]
Diagram of RF Sputtering including Substrate Bias. Source: [4]
23. Design Approach
Justification to Incorporate N2
Gas into Film:
• Increasing sheet resistance = smaller mean
free path of electrons (more defects in film
microstructure) [5]
• Add atoms that bond to the amorphous
network. Saturation point: atoms added as
point defects [5]
• Nitrogen already a part of the target in the
CVC System chamber [5]
Diagram of RF Sputtering including Substrate Bias. Source:
[4]
24. Design Approach
N2
:Ar Gas Ratio
S.M. Kang, et al, showed that
increased presence of N2
gas
in chamber increases sheet
resistance. Sheet resistance of
thin film significantly increases
above ~10%[1].
Gas flow rates calculated
accordingly.
25. Design Approach
Deposition Time
● Keysight suggested deposition time of 20 minutes
○ Confirmed by Kang, et al, in their experiment [1]
● Useful equation: Rs
proportional to 1/t
○ Rs
= sheet resistance (ohm/sq.)
○ t = thickness (Å)
● Keep thickness in range
○ Q * T = t
○ Q = deposition rate (Å/s, assumed constant)
○ T = deposition time (s)
26. Design Approach
Machine for Stress Measurements: Tencor P2 Long Scan
Profiler
• Stressed films bend substrates outward (compressive stress) or inward (tensile
stress) [6]
• Tencor P2 determines film stress by measuring sample’s change in curvature
between two tests [6]
• Measured wafer’s initial stress before deposition [6]
• After deposition, wafer is measured again to determine film stress, which is
calculated from wafer’s change in curvature [6]
E = Young’s modulus of substrate
v = Poisson’s ratio of substrate
ts
= Thickness of substrate
tf
= Thickness of film
r = Radius of curvature
L=Length of trace
B=Maximum between chord and trace
Photo of Tencor P2 Long
Scan Profiler. Source: [6]
σ=Ets
2
/6r(1-ν)tf
r=L2
/8B, L>>B
27. Design Approach
Machine for Thickness Measurement: Tencor P12
Profilometer
• Surface stylus profilometry determines change in height across sample.
• Patterned photoresist was applied onto silicon wafers before deposition.
• WSiN films were deposited onto patterned silicon wafers.
• After deposition, acetone was used to strip away photoresist.
Tencor P12 Profilometer. Source:
[9]
Resist/Deposition/Strip sequence.
Source:[17]
28. Design Approach
Machine for Rs
Measurements: 4P Automatic Four Point Probe, 280C
● Current passes through the outer two probes and film [7]
● Voltage across two inner probes is measured [7]
● Rs
= 4.53 x V/I [7]
● Measures at 25 points for average Rs
value.
Schematic of Four Point Probe
machine. Source: [7]
280C Four Point Probe, Model 4D. Source: [8]
29. Design Approach
Machine for Surface Topography and Chemical
Composition: FEI SCIOS Dual Beam FIB/SEM
● Scanning Electron Microscope (SEM)
○ Surface topography and composition at high
resolution
○ Electron beam shoots at sample and interacts
● Energy-Dispersive X-ray Spectroscopy (EDXS)
○ Separates characteristic X-rays into elements
○ Relative amounts of elements in sample
● Electron Backscatter Diffraction (EBSD)
○ Measures electrons diffracted from atomic planes
○ If crystalline, gives crystal orientation and grain
size.
Photograph of a SEM. Source: [16]
Interaction of Electron Beam with sample.
Source: [16]
30. Design Approach
Machine for Measuring Film Properties:
PANalytical X’Pert PRO
• X-Ray Reflectivity (XRR)
• Shoots X-Rays at film sample from a
range of small, grazing angles.
• X-rays reflect toward detector.
• Gives information about film
thickness, density, surface
roughness, and degree of
crystallinity.
Basic concept of XRR.
PANalytical X’Pert PRO.
32. Outline
1. Problem Identification
2. Design Approach
3. Evaluation
4. Conclusion and
Recommendations
A. Overview
B. Testing Result
a. Sheet Resistance
b. Thickness
c. Stress
d. Morphology
C. Assessment + Cost Analysis
D. Future works/ Next steps
33. Overview of Results
● Graph compares our last 3
wafers using all of the
same final parameters:
○ Dep time= 1027 s
○ 15% N to Ar ratio
● Rs
close to 2000
● Good consistency
● Wafers 9 and 10:
sputtered simultaneously
34. Sheet Resistance
• 8: batch-to-batch comparison
• 9 and 10: wafer-to-wafer
comparison
• Standard engineering margin of
error = 3%
• Note: 9 and 10 only have same
RS
, not std. dev. or uniformity.
Wafer
Number
#8 #9 #10
Rs (Ω/sq) 1975 2060 2060
Margin of
Error (%)
1.25 3.00 3.00
Std.
Deviation
(%)
5.64 5.86 6.05
Uniformity
(%)
10.13 10.61 11.12
35. Causes of Variation
● Target condition affects
sputtering:
○ Wear pattern directs
sputtered atoms
○ Batch-to-batch variation
● Old sputtering system
A used sputtering target (left) compared to a
new target (right). Source: [4]
36. Nitrogen Gas Ratio Dependence
• Ratio test range: 10-20% N2
/Ar
• Agrees with other experiments
• Exponential curve, just as Kang
et al
• Reinforces P. Homhuan’s work:
theory of N “interstitials”
• Shorter mean free path for
electrons
37. Film Thickness Dependence
• Dep time was altered after
viewing results of 15% N to fine
tune RS
• Thinner films yield higher RS
(less is more)
• RS
∝1/t
• Left most point: prone to
statistical error, still within one
standard deviation
38. Thickness
● Results
○ Wafer 8: 915 Å
○ Wafers 9, 10: 974 Å
● Average of 5 measurements
● All thicknesses within
prescribed range 750 Å-1500 Å
● Some unexpected variation
WSiN Film
Si Substrate
41. Thickness
Wafer 8
Wafer 9
● Variation
○ Q=QAVG
○ Assumed constant
● Q∝γ →Q=ICγ [11]
○ Ion current I, sputtering
system constant C not
expected to change
○ Sputtering yield γ must
change
■ Age of target
42. Thickness
● Variation
○ Q=QAVG
○ Assumed constant
● Q∝γ →Q=ICγ [11]
○ Ion current I, sputtering
system constant C not
expected to change
○ Sputtering yield γ must
change
■ Age of target
A used sputtering target (left) compared to a
new target (right). Source: [4]
44. Stress
● Residual vs. thermally induced stresses
○ Thermal stress not significant [8]
● Residual stress due to
○ Ar+
contamination
○ Densification effects
● Stress reduction due to
○ Change in microstructural regime [15]
■ Further characterization to
confirm
46. Stress
● No delamination or buckling was observed
● Stress greater on GaAs substrates than on Si
substrates
○ Lattice constants, CTE
● Stress on GaAs can be reduced by annealing
[3]
○ Possible increase in resistivity [4]
47. Morphology
• Previous studies of
WSiN thin films
suggested our film
would be amorphous
[3,4]
• EBSD showed no
crystallinity
• XRD indicates degree
of roughness
X-ray reflectivity curve
53. Overall Cost
Investment Type Cost
Materials $600
Characterization $600
Labor $81K
TOTAL $82K
● Previous Estimated Cost = ~220K
○ Savings of 220K - 82K = $138K
54. Return on Investment
● Estimated Leverage Sales (Keysight Technologies) - $13M/year
○ $10M HBTs, $3M SFSs
● Estimated Cost of Production is Half the Estimated Sales
○ $13/2 = $6.5M Cost of Investment
○ Total Cost = Production + Labor = $6.5M + $82K = $6.582M
● Estimated Time of Return on Investment Based on Information Provided
○ $6.582M/$13M/yr = ½ Year
57. Conclusion
Result
● 2000 Ohm/sq.
● 3% difference in
range
● 10% standard dev.
Risks and Concern
● There is a run to
run variation which
will affect the data
● Must watch out for
the life cycle of the
target.
Recommendation
● 750W power
● -60V constant biasing
● 10 mTorr Total
Pressure
● 40 sccm flow rate
● A 15% nitrogen to
argon flow
● 1027 sec. deposition
time
58. Future Works
1. Possible pre-production for HBT/SFS
2. Use product substrates
a. GaAs and InP
3. Further Characterization
a. Determine film composition
i. Rutherford Backscattering Spectrometry, XPS (ESCA),
Auger spectroscopy for impurities
b. Thermal Coefficient of Resistance
i. Variety of carefully controlled experiments.
59. Acknowledgements
The authors would like to thank:
• Nick Kiriaze
• Rijuta Ravichandran
• Steven Zhang
• Ricardo Castro
• Michael Powers
• Vache Harotoonian
• Erkin Seker
60. References
1.) 280C, Four Point Probe Resistivity Mapping System. Digital image. WOTOL, Buy&Sell Industrial Equipment Worldwide. Web.
2.) A. Hirata, K. Machida, S. Maeyama, Y. Watanabe, H. Kyuragi, Diffusion Barrier Mechanism of Extremely Thin Tungsten Silicon Nitride Film Formed by ECR Plasma Nitridation, Japanese Journal of
Applied Physics, vol. 37, part 1, no. 3S, pp. 1251-1255, March 1998
3.) A. Lahav, K. A. Grim, I. A. Blech, Measurement of thermal expansion coefficients of W, Si, WN, and WSiN thin film metallizations, Journal of Applied Physics, vol. 67, no. 2, pp. 34-738, January 1990
4.) A. Vomiero, et al, Composition and resistivity changes of reactively sputtered W-Si-N thin films under vacuum annealing, Applied Physics Letters, vol. 88, no. 3, 031917-1-031917-3, January 2006
5.) Four Point Probes (2013), Sheet Resistance and the Calculation of Resistivity or Thickness Relative to Semiconductor Applications [Online], Available: http://four-point-probes.com/sheet-resistance-
and-the-calculation-of-resistivity-or-thickness-relative-to-semiconductor-applications/
6.) Franceschinis, Gianni. "Surface Profilometry as a Tool to Measure Thin Film Stress, A Practical Approach." (2005). Microelectronics Engineering Department, Rochester Institute of Technology. Web.
30 May 2015.
7.) G Franceschinis, Surface Profilometry as a tool to Measure Thin Film Stress, A Practical Approach, vol. 1, no. 1, pp. 1-5, 1999
8.) J. H. Kim, K. W. Chung, Microstructure and properties of silicon nitride thin films deposited by reactive bias magnetron sputtering, Journal of Applied Physics, vol. 83, no. 11, pp. 5831-5839, May 1998
9.) M. Powers, Sputter Deposition of Thin Films in HFTC, Santa Rosa, CA: Keysight Technologies, 2015. (slides)
10.) Pattira Homhuan, et al, Growth and Structural Characterizations of Nanostructured Chromium-Zirconium-Nitride Thin Films for Tribological Applications, Materials Transactions, vol. 51, no. 9, pp.
1651-1655, July 2010
11.) R. W. Berry, P. M. Hall, and M. T. Harris, Thin Film Technology, New York, NY: Wan Nostrand Reinhold Company, 1968
12.) “Semiconductors on NSM,” http://www.ioffe.ru/SVA/NSM/Semicond/ .Accessed May 28, 2015.
13.) S. M. Kang, et al, Control of electrical resistivity of TaN thin films by reactive sputtering for embedded passive resistors, Thin Solid Films, vol. 516, no. 11, pp 3568-3571, April 2008
14.) Wolfs, Frank L.H. "Superconductivity." Home Page of Frank L. H. Wolfs. Department of Physics and Astronomy, University of Rochester, 1996. Web. 30 May 2015.
15.) Y. G. Shen, et al, Composition, residual stress, and structural properties of thin tungsten nitride films deposited by reactive magnetron sputtering, Journal of Applied Physics, vol. 88, no. 3, pp. 1380-
1388, July, 2000
16.) Takamura, Yayoi. Scanning Electron Microscope. Digital image. Department of Chemical Engineering and Materials Science, University of California, Davis. 7 Feb. 2013. Web.
17.) Effect of Etching Process. Digital image. VLSI Concepts. 28 July 2014. Web.