| 摘要 |
An in-situ measurement of thickness profiles of polishing pads (1) used in chemical mechanical polishing (CMP) is enabled by arranging sensors (7) for measuring distances together with a conditioner (6). The sensors (7) are provided as e.g. laser sensors (7a-c) performing an indirect measurement from a calibrated height level above the pad (1) surface or as e.g. laser (7a-c) or ultrasonic sensors (7e) performing a direct thickness measurement from the pad surface to the pad-platen contact surface. A thickness profile (10) is obtained by co-moving the sensor (7a, 7b) with the conditioner (6) during conditioning or by leading a sensor (7c) along a guide-rail (14) above the pad surface (1) with e.g. a constant distance. A reference distance measurement to the polishing platen (2) can be achieved by a second sensor (7d) mounted at a position, where there is no pad on the platen (2), e.g. a hole or the edge. Using the arrangement a disadvantageous thickness profile (10) with a steep slope resulting in polishing inhomogeneities affecting semiconductor device (4) surfaces can be detected and a warning signal be issued. A destructing micrometer measurement is not necessary, thus prolonging the pad (1) lifetime and increasing the device yield. <IMAGE> |
