Constitutive response of passivated copper films to thermal cycling

The thermomechanical behavior of passivated thin copper films is studied. Stresses in copper films of thickness ranging from 125 to 1000 nm, deposited on quartz or silicon substrates and passivated with silicon oxide, were measured using the curvature method. The thermal cycling spans a temperature range from −196 to 600 °C. The measured mechanical behavior was found to be rate insensitive within the heating/cooling rate range of 5–25 °C/min. It was observed that the passivated films do not exhibit a significant stress relaxation at elevated temperatures that is normally found in unpassivated films. Furthermore, a significant strain hardening during the course of thermal loading was noted. Simple continuum plasticity analyses show that the experimentally measured stress–temperature response can only be rationalized with a kinematic hardening model. Analytical procedures for extracting the constitutive properties of the films that were developed on the basis of such a model are presented. The initial yield...

[1]  Yu-Lin Shen,et al.  VOIDING INDUCED STRESS REDISTRIBUTION AND ITS RELIABILITY IMPLICATIONS IN METAL INTERCONNECTS , 2000 .

[2]  Subra Suresh,et al.  Size effects on the mechanical properties of thin polycrystalline metal films on substrates , 2002 .

[3]  Yu-Lin Shen,et al.  STRESSES, DEFORMATION, AND VOID NUCLEATION IN LOCALLY DEBONDED METAL INTERCONNECTS , 1998 .

[4]  C. Thompson,et al.  Activation volume for inelastic deformation in polycrystalline Ag thin films , 2000 .

[5]  M. D. Thouless,et al.  Stress development and relaxation in copper films during thermal cycling , 1993 .

[6]  R. Armstrong,et al.  The plastic deformation of polycrystalline aggregates , 1962 .

[7]  Robert E. Reed-Hill,et al.  Physical Metallurgy Principles , 1972 .

[8]  Huajian Gao,et al.  Constrained diffusional creep in UHV-produced copper thin films , 2001 .

[9]  S. Suresh.  Fatigue of materials , 1991 .

[10]  A. Mendelson.  Plasticity: Theory and Application , 1968 .

[11]  Dirk N. Weiss,et al.  In situ transmission electron microscopy study of thermal-stress-induced dislocations in a thin Cu film constrained by a Si substrate , 2001 .

[12]  L. Freund,et al.  Dislocation Plasticity in Thin Metal Films , 2002 .

[13]  P. Flinn,et al.  Measurement and Interpretation of stress in aluminum-based metallization as a function of thermal history , 1987, IEEE Transactions on Electron Devices.

[14]  D. Michell.  Comments on “X-ray and calorimetric investigations of cold working and annealing of a gold-silver alloy” , 1958 .

[15]  C. Cabral,et al.  Effect of a surface layer on the stress relaxation of thin films , 1996 .

[16]  L. Himmel,et al.  Temperature Dependence of the Elastic Constants of Cu, Ag, and Au above Room Temperature , 1966 .

[17]  Frans Spaepen,et al.  Tensile testing of free-standing Cu, Ag and Al thin films and Ag/Cu multilayers , 2000 .

[18]  Eduard Arzt,et al.  Quantitative analysis of strengthening mechanisms in thin Cu films: Effects of film thickness, grain size, and passivation , 1998 .

[19]  C. Cabral,et al.  Mechanisms for microstructure evolution in electroplated copper thin films near room temperature , 1999 .

[20]  Y. Chou,et al.  The limiting grain size dependence of the strength of a polycrystalline aggregate , 1966 .

[21]  Eduard Arzt,et al.  Thermomechanical behavior of different texture components in Cu thin films , 2001 .

[22]  Daniel Josell,et al.  A new method for tensile testing of thin films , 1993 .

[23]  William D. Nix,et al.  Mechanical properties of thin films , 1989 .

[24]  W. Brückner,et al.  Dislocation accumulation and strengthening in Cu thin films , 2001 .

[25]  O. Kraft,et al.  Deformation behavior of thin copper films on deformable substrates , 2001 .

[26]  Paul A. Flinn,et al.  Measurement and interpretation of stress in copper films as a function of thermal history , 1991 .

[27]  A NEW METHOD TO STUDY CYCLIC DEFORMATION OF THIN FILMS IN TENSION AND COMPRESSION , 1999 .

[28]  J. Meakin,et al.  On the mechanism of work hardening in face-centred cubic metals, with special reference to polycrystalline copper , 1957 .

[29]  A. Evans,et al.  Stress evolution in passivated thin films of Cu on silica substrates , 1998 .

[30]  David T. Read,et al.  Young's modulus of thin films by speckle interferometry , 1998 .

[31]  Subra Suresh,et al.  Thermal cycling and stress relaxation response of Si-Al and Si-Al-SiO2 layered thin films , 1995 .

[32]  Jens Lothe John Price Hirth,et al.  Theory of Dislocations , 1968 .

[33]  Richard P. Vinci,et al.  Thermal strain and stress in copper thin films , 1995 .

[34]  W. Baldwin.  Yield strength of metals as a function of grain size , 1958 .

[35]  Y.-L. Shen,et al.  Analysis of thermal stresses in metal interconnects with multilevel structures , 2002, Microelectron. Reliab..

[36]  Ramnath Venkatraman,et al.  Separation of film thickness and grain boundary strengthening effects in Al thin films on Si , 1992 .