Wisconsin Alumni Research Foundation

Pawitterjit S Mangat

Henry Guckel

A method and apparatus for planarizing photoresist and/or metal microstructure layers is provided. Planarization is achieved by removing material from a workpiece by lapping using a diamond containing lapping slurry. A lapping machine is furnished with a lapping plate made of a soft metal material. The lapping plate is furnished with ridges of controlled height using a diamond conditioning ring with a specified grit size. Free diamonds in a liquid slurry are then sprayed onto the plate and embedded therein by a second conditioning ring. After the lapping plate is conditioned, the piece to be lapped is mounted on the lapping plate. A vacuum hold fixture or flat steel or glass mounting plate may be used. During lapping, additional diamond slurry is sprayed onto the lapping plate and driven into the plate by a ceramic conditioning ring. The size of diamonds in the diamond slurry are selected to control the shear forces applied to the surface being lapped and to achieve a desired surface finish. Polishing, using a cloth covered hard metal polishing plate and loose diamond slurry, may be employed after lapping to provide a smooth optical surface finish. The lapping and polishing method and apparatus of the present invention may be used for z-dimension height control, re-planarization, and surface finishing of precise single or multiple level photoresist-metal layers, or of individual preformed photoresist sheets or laminates thereof.

Growing community of inventors

Madison, WI, United States of America

Pawitterjit S Mangat