Patent ID: 7270595
Filing Date: 2007-09-18
Classification: B24B

Abstract:
1. A method of polishing a wafer using a polishing pad having a rotational axis and a polishing medium, the method comprising the steps of: a. providing a pad having a plurality of grooves, each groove having a major axis extending outwardly from near the rotational axis to a periphery of the polishing pad, the major axis representing the center line of each groove, and the plurality of grooves including: a first portion that extends outwardly from near the rotational axis in a straight or curved configuration along the major axis; and a second portion that extends outwardly with respect to the rotational axis, the second portion in communication with the first portion at a transition location within a wafer track and configured to slow outward flow of polishing medium by causing the polishing medium to follow an oscillating path having a frequency and an amplitude along the major axis, the transition location transitioning the straight or curved configuration of the first portion to the frequency and amplitude of the oscillating portion; b. engaging the pad with a surface of the article; c. effecting relative rotation between the pad and the article so that a track of the pad contacts the article; and d. causing the polishing medium to flow between the pad and the surface of the article within the plurality of grooves in a manner such that the polishing medium has a first residence time in the first portion until reaching a transition point within a wafer track at which the residence time increases as a step function to a second residence time in the second portion, wherein the polishing medium is caused to flow along an oscillating path after reaching the transition point.