Arrangement and method for conditioning a polishing pad

Abstract

An in-situ measurement of thickness profiles of polishing pads () used in chemical mechanical polishing (CMP) is enabled by arranging sensors () for measuring distances together with a conditioner (). The sensors () are provided as e.g. laser sensors () performing an indirect measurement from a calibrated height level above the pad () surface or as e.g. laser () or ultrasonic sensors () performing a direct thickness measurement from the pad surface to the pad-platen contact surface. A thickness profile () is obtained by co-moving the sensor (7) with the conditioner () during conditioning or by leading a sensor () along a guide-rail () above the pad surface () with e.g. a constant distance. A reference distance measurement to the polishing platen () can be achieved by a second sensor () mounted at a position, where there is no pad on the platen (), e.g. a hole or the edge. Using the arrangement a disadvantageous thickness profile () with a steep slope resulting in polishing inhomogeneities affecting semiconductor device () surfaces can be detected and a warning signal be issued. A destructing micrometer measurement is not necessary, thus prolonging the pad () lifetime and increasing the device yield.