METHOD AND APPARATUS FOR DETERMINING SHEAR FORCE BETWEEN THE WAFER HEAD AND POLISHING PAD IN CHEMICAL MECHANICAL POLISHING

摘要

PURPOSE: A method and an apparatus for determining shear force between a wafer head and a polishing pad in a chemical mechanical polishing(CMP) process are provided to improve the precision of the shear force by including a plate which slides between the center of the polishing pad and the wafer head. CONSTITUTION: A CMP tool(10) is located on a wafer head(12). The CMP tool includes a rotary unit(14), a diamond conditioner disc(16) and a polishing pad(20). The wafer head and a support unit are placed on a plate. The plate is connected to the framework of the CMP tool by a low friction movement unit. The low friction movement unit slides to a vertical direction to the center of the polishing pad and the wafer head. A load cell sensor is fixed to the framework of the CMP tool. Shear force is determined according to signal from the load cell sensor.