Friction sensor for polishing system

摘要

A system method and apparatus to monitor a frictional coefficient of a substrate undergoing polishing is described. A polishing pad assembly includes a polishing layer including a polishing surface, and a substrate contacting member flexibly coupled to the polishing layer having a top surface to contact an exposed surface of a substrate. At least a portion of the top surface is substantially coplanar with the polishing surface. A sensor is provided to measure a lateral displacement of the substrate contacting member. Some embodiments may provide accurate endpoint detection during chemical mechanical polishing to indicate the exposure of an underlying layer.

主权项

1. An apparatus to monitor a frictional coefficient of a substrate undergoing polishing, comprising:
a support to hold a polishing article with a polishing surface; a carrier to hold an outer surface of the substrate against the polishing surface; a member laterally movable relative to the support and the carrier and having a top surface to contact the outer surface of the substrate as the substrate is held by the carrier with the outer surface against the polishing surface; a first restorative material configured to apply a first force on the member in a direction parallel to the polishing surface to urge the member relative to the support toward a neutral lateral position; a second restorative material configured to apply a second force on the member in a direction perpendicular to the polishing surface to urge the member toward the outer surface; and a sensor to generate a signal based on a lateral displacement of the movable member.