A novel evaluation method for thin films mechanical characterizations using cutting system

Abstract

In this study, we suggest a nano-cutting system to determine the shear strength of the thin films using fracture mechanics analysis of the diamond blade. Based on Merchant's cutting model, we analyze the thin films cutting process with regard to shear angle and resistant forces as initiation of the yield in the chip to establish a direct correlation between the cutting forces and the shear strength. Validating the proposed method was conducted using homogenous polycarbonate disk showing similar shear strengths between different cutting directions. Next, we examined a thin copper electroplated film used in traces of printed circuit board. A thin copper film was examined and found the intrinsic shear strength (307.5 MPa) and adhesion force (44 N/m) between the film and substrate. The result was comparable with tensile strength values reported in the literatures. Finally, we used SEM to visually verify the feasibility of nano-cutting technique to determine thin film properties.