Browse Prior Art Database

Printed Circuit Manufacture

IP.com Disclosure Number: IPCOM000080035D
Original Publication Date: 1973-Oct-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Frankenthaler, JJ: AUTHOR

Abstract

This is a method of preventing cross exposure of photoresist on thin laminates circuitized by an additive process.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

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Printed Circuit Manufacture

This is a method of preventing cross exposure of photoresist on thin laminates circuitized by an additive process.

Photoresist is generally applied to both sides of an epoxy glass substrate concurrently in a single operation to reduce cost. The desired patterns are then exposed and developed on each side separately. An epoxy glass substrate of normal off-white color transmits sufficient light energy in the 330-450 m mu range during the exposure of photoresist on one side, to undesirably cause cross linking of the photoresist on the opposite side.

This undesirable cross exposure is prevented by adding the following dye to the epoxy glassed formulation during formation of the substrate: Brilliant Blue GN and Orange 2R, in the ratio of 4 parts blue by weight to 3 parts orange. The total parts per hundred resin was 0.21 to 0.35 depending on the resin loading and final laminate thickness.

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