Characterization of Mechanical Properties of Thin Film Using Residual Compressive Stress Sung-Jin Cho, Jin-Won Chung, Myoung-Woon Moon and Kwang-Ryeol Lee Korea Institute of Science and Technology 미세구조 Workshop, 강원도 평창군 피닉스파크

Residual Stress of Thin Films Thin films typically support very high stresses due to the constraint of the substrate to which they are attached

Residual Compressive Stress of DLC Film Film Deposition

Telephone Cord Buckling M.W.Moon et al, Acta Mater., 50 (2002) 1219.

Off-Piste Run in Hoghfügen

Buckling Configurations

Quantitative Analysis K.-R. Lee et al, Diam. Rel. Mater., 2 (1993) 218.

What can we do with this phenomenon? Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films

What can we do with this phenomenon? For Isotropic Thin Films

Measurement of Residual Stress Curvature (R) Ds DfDf

What can we do with this phenomenon? For Isotropic Thin Films

DLC Bridges by Micro Fabrication DLC film Deposition ( on SiO 2 ) DLC Patterning SiO 2 Isotropic Wet Etching Wet Cleaning Strain Estimation

C 6 H 6, 10mTorr, -400V, 0.5  m 150  m Microstructure of DLC Bridges

Strain of the Buckled Thin Films Z X 2A 0

Effect of Bridge Length  m

Dependence of Film Thickness

 V  V  V  V DLC Bridges

Biaxial Elastic Modulus

DLC film Deposition Cleavage along [011] Direction Si Etching (by KOH Solution) Wet Cleaning Strain Measurement Preparation of Free Overhang

Free Overhang Method Biaxial elastic modulus Strain of the free overhang

A 0 / λof Free-hang at 546 nm I II III a-C:H, C 6 H V

5.6 ㎛ 11.3 ㎛ 2 ㎛ 11 ㎛ Effect of Etching Depth 546 nm 55 nm

Elastic Modulus for Various Ion Energies Nanoindentation t>1.0 ㎛

Advantages of This Method Simple Method Completely Exclude the Substrate Effect Can Be Used for Very Thin Films

Nano-indentation Substrate Effect is Significant. The elastic strain field >> the plastic strain field Substrate

Substrate Effect on the Measurement

Advantages of This Method Simple Method Completely Exclude the Substrate Effect Can Be Used for Very Thin Films

a-C:H, C 6 H V J.-W. Chung et al, Diam.Rel. Mater. 10 (2001) ta-C (Ground) Elastic Modulus of Very Thin Films

Biaxial Elastic Modulus

Structural Evolution of DLC Films Si Substrate J.-W. Chung et al, Diam.Rel. Mater., 11, 1441 (2002).

Residual Stress of ta-C film

Biaxial Elastic Modulus of ta-C film

Conclusions Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films

What can we do with this phenomenon? Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films

Fundamental Adhesion

Fundamental Adhesion DLC on Glass

Conclusions Can be a useful tool to estimate the fundamental interface toughness (adhesion) and the mechanical properties of thin films