Investigation on the effect of surface roughness on the fracture strength of SCS

Studies have found that fracture strength increases when chip thickness decreases. However, the effect of thickness interacts with the effect of roughness during the manufacturing. Therefore, to understand the individual impact, decoupling the effect of thickness and roughness is important. Consequently, this research focuses on the effect of roughness on the strength of single crystal silicon (SCS). A new method was developed to investigate the effect of surface roughness on the fracture strength of SCS. A finite element (FE) model with an equivalent notch was established according to measured roughness parameters, and the effect of stress concentration was simulated. A three-point bending test was used to determine the mean displacement to fracture (Df) of the samples. By applying the mean Df to a previous model, the fracture strength, including the effect of roughness, was obtained. The chip strengths obtained under different roughness was similar using the method above. The fracture strength of SCS, including the effect of roughness, was approximately 2.2 GPa.