Primary study on nonlinear viscoelasticity measurement of chemical mechanical polishing pads by applying on-machine compression test

Polishing pads used for chemical mechanical polishing (CMP) process have strong nonlinear viscoelasticity, which is considered to affect resultant polishing performance. In order to evaluate the material properties of polishing pads, a series of fundamental compression tests were conducted by using a developed on-machine compression tester. From measured stress–strain curves, parameters representing nonlinear elasticity and viscosity of the CMP pads are identified. Analytical results indicated unique nonlinear elasticity due to pad surface asperities and not negligible viscous damping.