Patent ID: 6190118
Filing Date: 2001-02-20
Classification: H01L,Y10S

Abstract:
A method for sequentially unloading a plurality of silicon wafers housed within a cassette configured to hold said wafers, said cassette being secured to a tilt mechanism which is mounted entirely above a worktable of a chemical mechanical planarization machine, said method comprising the following steps:(a) verifying with a control system that said cassette is in a planar state relative to a robotic arm configured to retrieve said wafers from said cassette;(b) retrieving a wafer from said cassette with said robotic arm and moving said robotic arm away from said cassette to a central position;(c) signaling said control system that step(b) has been completed;(d) actuating said tilt mechanism to tilt said cassette back to a position wherein said wafers held by said cassette are gravity-loaded against a rear portion of said cassette;(e) transferring said retrieved wafer with said robotic arm to a subsequent processing station;(f) signaling said control system that step (e) has been completed;(g) actuating said tilt mechanism to move said cassette back to said planar state relative to said robotic arm; and(h) repeating steps (a)-(g) until all of said wafers have been unloaded from said cassette.