Response of Thin Films and Substrate to Micro Scale Laser Shock Peening

Micro-scale laser shock peening (mu LSP) can potentially be applied to metallic structures in microdevices to improve fatigue and reliability performance. Copper thin films on a single-crystal silicon substrate are treated by using mu LSP and characterized using techniques of X-ray microdiffraction and electron backscatter diffraction (EBSD). Strain field, dislocation density, and microstructure changes including crystallographic texture, grain size and subgrain structure are determined and analyzed. Further, shock peened single crystal silicon was experimentally characterized to better understand its effects on thin films response to mu LSP. The experimental result is favorably compared with finite element method simulation based on single-crystal plasticity.