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Browse Prior Art Database

Apparatus for Exposure of Inner Walls of Apertures

IP.com Disclosure Number: IPCOM000093590D
Original Publication Date: 1967-Nov-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Rottman, HR: AUTHOR

Abstract

The apparatus is for the transmission of light to enclosed areas such as apertures during the formation of printed circuits within such apertures by conventional subtractive methods. The latter include exposure of a photoresist coating to light through a mask and subsequent development leaving a pattern of cross-linked photoresist over a metal coating. The metal coating not covered by the photoresist pattern is then etched away leaving a printed circuit pattern corresponding to that of the photoresist.

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Apparatus for Exposure of Inner Walls of Apertures

The apparatus is for the transmission of light to enclosed areas such as apertures during the formation of printed circuits within such apertures by conventional subtractive methods. The latter include exposure of a photoresist coating to light through a mask and subsequent development leaving a pattern of cross-linked photoresist over a metal coating. The metal coating not covered by the photoresist pattern is then etched away leaving a printed circuit pattern corresponding to that of the photoresist.

The formation of printed circuits on three-dimensional objects such as magnetic cores presents a problem with respect to the exposure of the photoresist coating within recesses or apertures such as the central aperture in a magnetic core. These openings usually have such small dimensions that a light source cannot be practically inserted into the opening. On the other hand, because of the constricted nature of the aperture, external light applied to the aperture does not have the uniform intensity necessary for the formation of high- resolution photoresist patterns.

In order to provide light of uniform intensity within the aperture, light pipes in the form of fiber bundles are inserted into the aperture so that the individual fibers terminate within the mask openings. These fibers transmit light of uniform intensity to the photoresist through the openings in the mask. Alternatively, a quartz or glass rod with a rou...