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Process to Make Fine Line Circuitry

IP.com Disclosure Number: IPCOM000050807D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ellis, TL: AUTHOR [+2]

Abstract

Circuitry can be fabricated utilizing one glass master and two photoresists, one positive and one negative. The positive resist is applied to a .0002 inch thick layer of copper, exposed, developed, and etched to produce a copper line .0002 inch high and any desired width. The resist is then stripped. A negative resist is then applied to the panel. This will adhere to the rough surface created when the .0002 inch copper was etched off. Using the same glass master, the panel is exposed and developed, leaving the copper lines clear of resist. The panel is then additive plated so the lines are plated to a desired height.

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Process to Make Fine Line Circuitry

Circuitry can be fabricated utilizing one glass master and two photoresists, one positive and one negative. The positive resist is applied to a .0002 inch thick layer of copper, exposed, developed, and etched to produce a copper line .0002 inch high and any desired width. The resist is then stripped. A negative resist is then applied to the panel. This will adhere to the rough surface created when the
.0002 inch copper was etched off. Using the same glass master, the panel is exposed and developed, leaving the copper lines clear of resist. The panel is then additive plated so the lines are plated to a desired height.

After the lines are plated, the photoresist is removed, leaving clean straight walled lines. This process eliminates: 1. Chemical processes used to get the photoresist to adhere to copper during a long additive plating process. 2. Resist lifts causing under plate of lines and shorted-out lines. The advantages of this process are: 1. By using a positive resist and then a negative resist, you need only one glass master. 2. The glass master can utilize two round and one diamond pin for registration. This allows better registration on

the second expose operation. 3. If opens were detected after the first photoresist operation, the panel can be seeded prior to the application of the

second resist. When the panel is placed in an additive bath,

these opens are plated shut.

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