Improvement of the cantilever beam technique for stress measurement during the physical vapor deposition process

An improvement of an optical method for in situ measurement of the intrinsic stress in thin films is described. The method presented is based on the well-known beam bending technique using the deflection of a laser beam that reflects itself on a sample. The first new development lies in the evaluation of the bending plate equation. The second uses image processing to determine the deformation of the sample. The method has been applied to pure chromium films on glass substrates to validate the stress measurements. The reproducibility of stress measurement is of about 8%. Results show the great adaptability of the technique to any kind of stress evolution during the physical vapor deposition process and give additional information about the evolution of stress versus film thickness, in comparison with ex situ techniques. Finally, a correlation between stress measurement and microstructure has been carried out.

[1]  M. Janda On the intrinsic stress in thin chromium films , 1986 .

[2]  Sung-chul Shin,et al.  In situ stress measurements of Co/Pd multilayer films using an optical non-contact displacement detector , 1995 .

[3]  J. H. Dautzenberg,et al.  Mechanical measurement of the residual stress in thin PVD films , 1995 .

[4]  E. R. Bradley,et al.  Correlation between the stress and microstructure in bias-sputtered ZrO2-Y2O3 films , 1984 .

[5]  D. W. Hoffman,et al.  Internal stresses in sputtered chromium , 1977 .

[6]  D. W. Hoffman,et al.  Stress-related effects in thin films , 1989 .

[7]  W. D. Westwood,et al.  Glow discharge sputtering , 1976 .

[8]  F. J. V. Preissig Applicability of the classical curvature-stress relation for thin films on plate substrates , 1989 .

[9]  A. Korhonen,et al.  Improved corrosion resistance of physical vapour deposition coated TiN and ZrN , 1990 .

[10]  J. Machet,et al.  Deposition of corrosion-resistant chromium and nitrogen-doped chromium coatings by cathodic magnetron sputtering , 1996 .

[11]  G. Stoney The Tension of Metallic Films Deposited by Electrolysis , 1909 .

[12]  Andrew K. C. Wong,et al.  A new method for gray-level picture thresholding using the entropy of the histogram , 1985, Comput. Vis. Graph. Image Process..

[13]  R. Fillit,et al.  Structure and mechanical properties of reactively sputtered chromium nitrides , 1991 .

[14]  G. Moulard,et al.  An improved optical cantilever technique using image processing for measuring in situ stress in thin films , 1997 .

[15]  E. Suhir An approximate analysis of stresses in multilayered elastic thin films , 1988 .

[16]  F. Richter,et al.  Determination of mechanical properties of thin films: a theoretical feasibility study , 1993 .

[17]  D. W. Hoffman Perspective on stresses in magnetron‐sputtered thin films , 1994 .

[18]  P. Martin,et al.  Ion-based methods for optical thin film deposition , 1986 .

[19]  F. d'Heurle,et al.  Note on the origin of intrinsic stresses in films deposited via evaporation and sputtering , 1989 .

[20]  Weber,et al.  UHV cantilever beam technique for quantitative measurements of magnetization, magnetostriction, and intrinsic stress of ultrathin magnetic films. , 1994, Physical review letters.

[21]  R. W. Hoffman,et al.  The origins of stress in thin nickel films , 1972 .

[22]  T. Page,et al.  The determination of residual stresses in thin coatings by a sample thinning method , 1990 .

[23]  D. Campbell,et al.  A sensitive bending beam apparatus for measuring the stress in evaporated thin films , 1969 .

[24]  Intrinsic Stress in Evaporated Metal Films , 1968 .

[25]  Brian D. Harper,et al.  A geometrically nonlinear model for predicting the intrinsic film stress by the bending-plate method , 1990 .

[26]  H. Windischmann Intrinsic Stress in Sputter Deposited Thin Films , 1992, Optical Interference Coatings.

[27]  R. Abermann,et al.  Measurements of the intrinsic stress in thin metal films , 1990 .