Patent ID: 6889177

Claim:
A method for pseudo-physically modeling the erosion of the surface of a workpiece being polished by a stack of polishing pads including a base pad and a top pad, said method comprising the steps of: a) determining the contact force between the surface of the workpiece being polished and the stack of polishing pads by: 1) equating the base pad to a first abstract mathematical spring having compressibility factor k1; 2) equating the top pad to a second abstract mathematical spring having compressibility factor k 2 ; 3) said first and second abstract mathematical springs being connected together in series; 4) determining the force on the stack of polishing pads by determining the combined deflection of the base pad and the top pad; b) equating the force on the stack of polishing pads to the force on the surface of the workpiece being polished; c) determining the erosion rate of the surface of the workpiece being polished by multiplying the force on the surface of the workpiece being polished by a predetermined constant.