Allegro Microsystems, LLC

Thomas J Martiska

Jay J Gagnon

Paul J Panaccione

Paul A Guillotte

Stephen Darling

A method of fabricating a patterned polyimide film on a semiconductor wafer including spin coating the wafer with a polyimide precursor solution, baking the polyimide precursor solution in order to remove solvents from and to slightly cure the solution to form a polyimide film, and rinsing the polyimide film with deionized water immediately following the baking step prior to further processing. The rinsing in part serves to further remove solvents associated with the polyimide film. The process continues with photolithography techniques in which the wafer spin coated with a selected photoresist to form a photoresist film immediately following the rinsing step, and a baking of the photoresist film. Thereafter, the photoresist film is exposed to radiation through a photomask, and developed with a solution to form a pattern. The pattern is then etched into the polyimide film with the solution. The remaining portions of the photoresist are removed with a chemical stripper. The wafer is then baked to fully cure the pattern formed in the polyimide film. The present invention provides an improved semiconductor fabrication process which yields better defined patterns and greatly enhances the uniformity and repeatability of the photolithographic process.

Method of semiconductor fabrication utilizing rinse of polyimide film

A uniformly thick dielectric polyimide coating is provided on the back face of an integrated circuit and the die is mounted to a copper lead frame finger by interposing an epoxy resin bonding agent between the uniformly thick polyimide coating and the copper support finger. The die coating is provided before separating die from the precursive water. Liquid polyimide is poured onto the back side of the water which is spun, in a manner similar to that usually used for obtaining uniformly thick photoresist films. After curing the polyimide, the die are cut from the wafer by sawing.

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Shrewsbury, MA, United States of America

Thomas J Martiska