Inventors:
Josephine Harbarger - Phoenix AZ
Assignee:
Motorola Inc. - Schaumburg IL
International Classification:
B44C 122
H01L 21306
C03C 1500
C03C 2506
Abstract:
An improved means and method for polishing or lapping thin wafers, especially semiconductor wafers, in a lapping plate is obtained by providing additional slurry holes in the lapping plate between the wafer receiving holes. In a first embodiment useful with wafers having a small initial taper, the additional slurry holes are radially oriented and have a length about equal to the wafer diameter so that, as the lapping plate rotates in the lap machine, the lapping slurry feeds through the holes to providing slurry uniformly to the underside of the wafers being lapped. In a second embodiment useful for wafers with a large initial taper, slurry holes of varying width and/or length are used to vary the amount of slurry reaching different parts of the wafers so that a predetermined variation in lapping occurs across the wafer to correct the taper. Yield is thereby improved.