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Stripper for Photoresist Material

IP.com Disclosure Number: IPCOM000095788D
Original Publication Date: 1964-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Mutnick, S: AUTHOR

Abstract

In the manufacture of printed circuits, copper foil bonded to a dielectric base is coated with a photoresist. It is then exposed to light through a film negative delineating the desired circuit. After etching the circuit, it is necessary to remove the exposed photoresist, such as KPR*, from the copper without attacking the copper or the adhesive between copper and dielectric. Commercial strippers are satisfactory for removal of KPR from phenolic type bases. However, for MYLAR** base materials, the commercial strippers effect the polyester adhesive used.

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Stripper for Photoresist Material

In the manufacture of printed circuits, copper foil bonded to a dielectric base is coated with a photoresist. It is then exposed to light through a film negative delineating the desired circuit. After etching the circuit, it is necessary to remove the exposed photoresist, such as KPR*, from the copper without attacking the copper or the adhesive between copper and dielectric. Commercial strippers are satisfactory for removal of KPR from phenolic type bases. However, for MYLAR** base materials, the commercial strippers effect the polyester adhesive used.

The stripper comprises a solution of 50% by weight of N-methyl-2-pyrrolidone and 50% by weight of butyrolactone. Both substances are listed in the chemical handbooks as solvents for resins. Individually these materials do not react singly with a resist such as KPR. However, when combined they form a fast non- corrosive, non-toxic stripper acting at room temperature. The stripper does not attack the bond between copper and dielectric, but does quickly and cleanly remove the exposed photoresist. The part may then be washed in water.

Economically, this stripper has an advantage over most others in that it may be reclaimed for further use. Water in the stripper should be kept at a minimum. *Trademark of Eastman Kodak Co. **Trademark of E. I. du Pont de Nemours & Co.

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