CARRIER HEAD PROVIDING UNIFORM UPWARD AND DOWNWARD FORCE ON A WAFER

摘要

A wafer carrier head assembly for holding a wafer in chemical mechanical planarization applications is dis;losed that includes a downwardly protruding wafer retaining ring that moves independent of the wafer carrier head and retains an edge of the wafer on said polishing surface. An adjustable wafer holding mechanism that applies one of a uniform downward force and a uniform upward force to the wafer is also included. Application of the upward force allows the wafer holding mechanism to retain and transport the wafer to a polishing surface. Application of the downward force allows the wafer holding mechanism to retain the wafer on the polishing surface and allows the wafer to be uniformly polished. The wafer carrier head assembly herein disclosed is also configured to pivotally accommodate changes in parallelism between the wafer and the polishing surface when the wafer is being polished.