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Preparation of Vias in Photosensitive Glass Layers

IP.com Disclosure Number: IPCOM000046618D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Shaw, RR: AUTHOR [+2]

Abstract

A photosensitive glass, after exposure to appropriate radiation (light, X-rays, electrons, etc.), can be crystallized by heat treatment into a desired via pattern. Depending upon the glass composition, the crystals can be either more or less soluble than the glass. Selective etching can then produce the desired vias. Different exposure conditions (time/intensity) yield different etch structure depths. Because of the high etching ratio between crystal and glass, the walls have only a small taper (2-10Œ, typically). The photosensitive elements (Cu, Ag, Au, etc.) can be introduced into bulk glass during initial batching. The resultant doped glass can be reduced to small particles and deposited as a thin powder layer, which can be fused.

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Preparation of Vias in Photosensitive Glass Layers

A photosensitive glass, after exposure to appropriate radiation (light, X-rays, electrons, etc.), can be crystallized by heat treatment into a desired via pattern. Depending upon the glass composition, the crystals can be either more or less soluble than the glass. Selective etching can then produce the desired vias. Different exposure conditions (time/intensity) yield different etch structure depths. Because of the high etching ratio between crystal and glass, the walls have only a small taper (2-10OE, typically). The photosensitive elements (Cu, Ag, Au, etc.) can be introduced into bulk glass during initial batching. The resultant doped glass can be reduced to small particles and deposited as a thin powder layer, which can be fused. Alternatively, the bulk glass can be evaporated to form a doped thin layer; undoped bulk glass can be co-evaporated with the dopant material, or an undoped glass layer can be doped by diffusion of the activator, after surface coating or ion implantation. Utilization of thin layers of such glass provides for the elimination of the photoresist for the deposition of thin films in the fabrication of electronic devices, including semiconductor and packaging devices. For multilevel metallurgy in the semiconductor art, the photosensitive glass provides for the elimination of a photolith step for exposing the glass, since the glass can be directly exposed. Also, one can achieve nearly strai...