Method for improving grinding uniformity of chemical mechanical planarization (CMP)

The present invention discloses a method for improving the uniformity of the chemical mechanical polishing abrasive, wherein the monitoring circuit is achieved by a monitoring circuit includes a controller connected in sequence, and the thickness of the cushion sensor, disposed above the cushion with the retainer member is connected at the other ; real-time monitoring of the degree of loss of thickness sensor retainer, the sensor signals the controller to control a thickness of cushion motion, the cushion retainer will be pushed outwards, in order to ensure the relative height of the retainer and the membrane during use of the pad retainer unchanged; when the thickness sensor detects a thickness of the retainer is consumed to a certain degree, the controller alarm signal. The present invention, by detecting the degree of loss of the retainer, the retainer out of the real launch mode, to ensure the relative height of the retainer and the spacer film is maintained constant during use of the retainer, a good CMP process avoids protection ring pressure fluctuations impact polishing uniformity.