scholarly journals Determination of Stresses in Incrementally Deposited Films From Wafer-Curvature Measurements

2020 ◽  
Vol 87 (10) ◽  
Author(s):  
Zhaoxia Rao ◽  
Hanxun Jin ◽  
Alison Engwall ◽  
Eric Chason ◽  
Kyung-Suk Kim
Keyword(s):  
Residual Stress ◽  
Finite Thickness ◽  
Deposition Process ◽  
Wafer Curvature ◽  
Curvature Measurement ◽  
Stressed Layer ◽  
Relaxation Stress ◽  
Curvature Measurements ◽  
Deposited Films

Abstract We report closed-form formulas to calculate the incremental-deposition stress, the elastic relaxation stress, and the residual stress in a finite-thickness film from a wafer-curvature measurement. The calculation shows how the incremental deposition of a new stressed layer to the film affects the amount of the film/wafer curvature and the stress state of the previously deposited layers. The formulas allow the incremental-deposition stress and the elastic relaxation to be correctly calculated from the slope of the measured curvature versus thickness for arbitrary thicknesses and biaxial moduli of the film and the substrate. Subtraction of the cumulative elastic relaxation from the incremental-deposition stress history results in the residual stress left in the film after the whole deposition process. The validities of the formulas are confirmed by curvature measurements of electrodeposited Ni films on substrates with different thicknesses.

Residual Stress in Sputtered Silicon Oxycarbide Thin Films

2011 ◽  
Vol 1299 ◽  
Author(s):  
Ping Du ◽  
I-Kuan Lin ◽  
Yunfei Yan ◽  
Xin Zhang
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Elevated Temperatures ◽  
Silicon Oxide ◽  
Composite Films ◽  
Deposition Process ◽  
Silicon Oxycarbide ◽  
X Ray ◽  
Curvature Measurement ◽  
Film Substrate

ABSTRACTSilicon carbide (SiC) has received increasing attention on the integration of microelectro-mechanical system (MEMS) due to its excellent mechanical and chemical stability at elevated temperatures. However, the deposition process of SiC thin films tends to induce relative large residual stress. In this work, the relative low stress material silicon oxide was added into SiC by RF magnetron co-sputtering to form silicon oxycarbide (SiOC) composite films. The composition of the films was characterized by Energy dispersive X-ray (EDX) analysis. The Young’s modulus and hardness of the films were measured by nanoindentation technique. The influence of oxygen/carbon ratio and rapid thermal annealing (RTA) temperature on the residual stress of the composite films was investigated by film-substrate curvature measurement using the Stoney’s equation. By choosing the appropriate composition and post processing, a film with relative low residual stress could be obtained.

Residual Stress Variation in Polysilicon Thin Films

2006 ◽  
Author(s):  
Andrew J. Mueller ◽  
Robert D. White
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Compressive Stress ◽  
Chemical Vapor ◽  
Stress Variation ◽  
Wafer Curvature ◽  
Mechanical Methods ◽  
Chemical Vapor Deposited ◽  
Pressure Chemical ◽  
Deposited Films

This paper compares the use of four mechanical methods for characterization of residual stress variation in low pressure chemical vapor deposited (LPCVD) polysilicon thin films deposited, doped, and annealed under different conditions. Stress was determined using buckling structures, vibrating microstructures, static rotating structures and the wafer curvature method. After deposition of 1.0 μm of polysilicon at 625°C and 588°C the stress in the wafers is 230 MPa compressive (stdev = 1.2 MPa) and 340 MPa compressive (stdev = 10.4 MPa), respectively. Deposition of 0.6 μm at 580°C results in a tensile stress of 66 MPa (stdev= 52 MPa). Following doping, all stresses are compressive. Boron doping of the 625°C and 588°C deposited films produces a compressive stress of 149 MPa (stdev= 28.6 MPa) and 100 MPa (stdev= 29.5 MPa). Phosphorous doping of the 588°C and 580°C deposited films produces a compressive stress of 54 MPa (stdev = 0.3 MPa) and 80 MPa (stdev= 5.3 MPa), respectively. Annealing through rapid thermal processing (RTP) at temperatures of 1000°C – 1100°C reduced the stresses by 20-50 MPa, but the stresses remained compressive. These values are measured using the wafer curvature method. Values obtained from the other microstructure methods agree with stresses determined by wafer curvature with the exception of the rotating structures which showed 20% lower stress readings.

scholarly journals Stoney Formula: Investigation of Curvature Measurements by Optical Profilometer

2014 ◽  
Vol 996 ◽  
pp. 361-366 ◽  
Author(s):  
Maria Rosa Ardigo ◽  
Maher Ahmed ◽  
Aurélien Besnard
Keyword(s):  
Residual Stress ◽  
Mean Value ◽  
Radius Of Curvature ◽  
Titanium Nitride Coating ◽  
Before And After ◽  
Optical Profilometer ◽  
Curvature Measurements ◽  
Stoney Formula ◽  
Substrate Influence

Thin films’ residual stress is often determined by the Stoney formula, using the measurements of the substrate curvature, even if the required hypotheses are not completely respected. In this study, a 2.2 µm titanium nitride coating was deposited by reactive sputtering on a silicon substrate. The Stoney formula was used in order to calculate the residual stress of the film. The radius of curvature was measured, before and after coating by optical profilometer, considering the whole surface of the sample. The effect of the substrate shape (square and rectangular) with various dimensions was investigated. We showed that the shape of the substrate influence strongly the deformation. Moreover, it was highlighted that the choice of the radius (maximum value, minimum value, mean value, with or without initial curvature correction) is critical to the determination of the stress.

Control of Stress with Growth Conditions and Mechanical Parameters Determination of 3C-SiC Heteroepitaxial Thin Films

2000 ◽  
Vol 657 ◽  
Author(s):  
C. Gourbeyre ◽  
T. Chassagne ◽  
M. Le Berre ◽  
G. Ferro ◽  
C. Malhaire ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Epitaxial Growth ◽  
Buffer Layer ◽  
Growth Conditions ◽  
Mean Value ◽  
Nano Indentation ◽  
Deposited Films

ABSTRACTWe report here on the influence of the epitaxial growth conditions on the residual stress of heteroepitaxial 3C-SiC grown on silicon using atmospheric-pressure chemical vapour deposition (APCVD) and on the determination of its mechanical properties. 3C-SiC films were grown on (100) Si substrates in a vertical reactor by APCVD. SiH4 and C3H8 are used as precursor gases and H2 as carrier gas. The growth procedure involves the formation of a carburization buffer layer at 1150°C under a mixture of H 2 and C3H8. The epitaxial growth occurs then at 1350°C by adding SiH 4.For as-deposited films the measurement techniques implemented are substrate curvature measurements, AFM, and nano-indentation. For micromachined self-suspended SiC membranes, load deflection measurements were used. The substrate curvature measurement leads to the determination of the residual stress in the deposited SiC film. We show that we can achieve 3C-SiC layers with a compressive or a tensile state having equivalent crystallinity. Whereas thermal mismatch just accounts for tensile stresses, we demonstrate that 3C-SiC thin films may have compressive stresses by using specific conditions for the formation of the buffer layer. The early stage of growth is indeed of major importance.Regarding the mechanical properties, the 3C-SiC Young's modulus was determined using nano-indentation. Its mean value reaches 378 GPa comparable to the calculated value of 307 GPa. As test structures, we have processed self-suspended SiC membranes. Load deflection measurements enable the determination of the Young's modulus and the residual stress of the self-suspended films. For self-suspended SiC membranes, the absolute value of the residual stress in the SiC thin films decreases compared to the as-deposited films and takes a mean value of 170 MPa in a tensile state.

Understanding residual stress in thin films: Analyzing wafer curvature measurements for Ag, Cu, Ni, Fe, Ti, and Cr with a kinetic model

2021 ◽  
Vol 130 (13) ◽  
pp. 135304
Author(s):  
Zhaoxia Rao ◽  
Sarah Berman ◽  
Peilin Yang ◽  
Diederik Depla ◽  
Eric Chason
Keyword(s):  
Thin Films ◽  
Residual Stress ◽  
Kinetic Model ◽  
Wafer Curvature ◽  
Curvature Measurements

Synchrotron White Beam Topography Studies of Residual Stress in SiC Single Crystal Wafers with Epitaxial Thin Films

1995 ◽  
Vol 399 ◽  
Author(s):  
W. Huang ◽  
Q. Wang ◽  
M. Dudley ◽  
F. P. Chiang ◽  
J. Parsons ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Energy ◽  
Epitaxial Thin Films ◽  
Multiple Diffraction ◽  
X Ray ◽  
Wafer Curvature ◽  
White Beam ◽  
Curvature Measurement ◽  
Reflection Geometry ◽  
Sic Wafer

ABSTRACTThe residual stress in a 6H-SiC wafer with a 3C-SiC epitaxial overlayer is determined by the technique of Synchrotron white beam x-ray topography (SWBXT). The short wavelength and high energy attributes of synchrotron radiation are exploited to very accurately determine the wafer curvature. Different approaches including absorption edge contour (AEC) mapping, multiple diffraction line (MDL) analysis and diffracted x-ray beam divergence (DXBD) analysis in both transmission and reflection geometry are demonstrated. The residual stress distribution is calculated from the wafer curvature measurement.

scholarly journals Thermal Stresses in Chemically Hardening Elastic Media With Application to the Molding Process

1974 ◽  
Vol 41 (3) ◽  
pp. 647-651 ◽  
Author(s):  
Myron Levitsky ◽  
Bernard W. Shaffer
Keyword(s):  
Residual Stress ◽  
Chemical Reaction ◽  
Thermal Stresses ◽  
Stress Component ◽  
Elastic Solid ◽  
Molding Process ◽  
Hardening Process ◽  
Exothermic Chemical Reaction ◽  
Component Parallel

A method has been formulated for the determination of thermal stresses in materials which harden in the presence of an exothermic chemical reaction. Hardening is described by the transformation of the material from an inviscid liquid-like state into an elastic solid, where intermediate states consist of a mixture of the two, in a ratio which is determined by the degree of chemical reaction. The method is illustrated in terms of an infinite slab cast between two rigid mold surfaces. It is found that the stress component normal to the slab surfaces vanishes in the residual state, so that removal of the slab from the mold leaves the remaining residual stress unchanged. On the other hand, the residual stress component parallel to the slab surfaces does not vanish. Its distribution is described as a function of the parameters of the hardening process.

Sign in / Sign up

Export Citation Format

Share Document