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Simultaneously Metallizing and Developing a Positive Photoresist

IP.com Disclosure Number: IPCOM000090290D
Original Publication Date: 1969-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Hall, DW: AUTHOR [+2]

Abstract

Attempts to plate electrolessly on positive photoresists fail because the resist is attacked by the alkaline plating baths. A developed pattern cannot be plated because the clear glass areas also take on a metallic coating. This method overcomes the disadvantages mentioned and consists in applying a photoresist to the transparent substrate, exposing it to the pattern desired, and baking it. Nucleation centers are then formed in the entire coating with suitable catalysts. Finally, the coating is simultaneously developed and electrolessly plated with the required metal. The basic steps are indicated in the drawing.

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Simultaneously Metallizing and Developing a Positive Photoresist

Attempts to plate electrolessly on positive photoresists fail because the resist is attacked by the alkaline plating baths. A developed pattern cannot be plated because the clear glass areas also take on a metallic coating. This method overcomes the disadvantages mentioned and consists in applying a photoresist to the transparent substrate, exposing it to the pattern desired, and baking it. Nucleation centers are then formed in the entire coating with suitable catalysts. Finally, the coating is simultaneously developed and electrolessly plated with the required metal. The basic steps are indicated in the drawing.

A positive photoresist is applied on a clean glass plate by spin-coating 30 seconds at 1500 rpm in the conventional manner, followed by a 10 minute bake at 65 degrees C. A regular exposure to the selected pattern is made and the specimen is then baked 20 minutes at 130 degrees C.

In sensitization, the plate is given 15 seconds in developer, rinsed 30 seconds under the faucet, and dried in nitrogen. After a 1-minute overflow rinse in deionized water, it is plated 30 seconds, the pH of the solution being adjusted to 0.89. This is followed by a 2-minute overflow rinse in deionized water, plating 30 seconds at a pH of 1.40 and a 2-minute overflow rinse in deionized water. The two-stage plating is then repeated, but this time ends with a five-minute rinse.

In the plate-develop step, the specimen...