System of using offset gage for CMP polishing pad alignment and adjustment

A method and system are provided using an offset dial gage for alignment and adjustment of a polishing pad that has been attached to a turntable of a chemical mechanical polishing (CMP) device. In a described embodiment, an offset dial gage has a surface that contacts a side of a turntable, while a sensor tip contacts the edge of a polishing pad positioned on the turntable. This provides an assessment of radial displacement of the polishing pad edge at this measurement point relative to the side of the turntable. Based on one or more such measurements, the polishing pad may be found acceptably positioned, may be trimmed, or may be replaced. The method and system reduce or eliminate the occurrence of a defect pattern found to be related to side unloading of semiconductor wafers from a CMP turntable.