Patent ID: 7234224

Claim:
A method for forming grooves in a polymeric polishing pad useful for the chemical mechanical planarization of a substrate, the substrate being at least one of magnetic, optical and semiconductor substrates comprising: rotating a cutting bit about an axis in a z-direction, the cutting bit rotating at a rate of at least 60,000 revolutions per minute, the rate being sufficient to melt the polymeric polishing pad upon low velocity contact with the polishing pad without cooling and having at least one cutting edge for cutting groove depth in the z-direction into the polymeric polishing pad; cutting the polishing pad in an x-direction and a y-direction to form at least one curved groove in the polymeric polishing pad, the x-direction and y-direction being perpendicular in a single plane and orthogonal to the z-direction, said cutting occurring by contacting the rotating cutting bit with a portion of the polymeric polishing pad, the at least one curved groove having polymeric sidewalls; ejecting cut debris from the polishing pad within the at least one groove with at least one flute in the rotating cutting bit; and varying velocity of the cutting in at least one of the x-direction or y-direction with a program-generated signal to guide the cutting through a curved path and to provide the at least one groove with a curved configuration in the polymeric polishing pad, the program-generated signal sending the cutting on a curved path while maintaining the velocity of the rotating bit to maintain a calculated chip thickness at a factor of 0.02 to 0.6 of a diameter of the rotating cutting bit and to reduce melting of the polymeric sidewalls of the polymeric polishing pad.