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Capillary Masking of Topologically Etched Silicon Substrates

IP.com Disclosure Number: IPCOM000049244D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Brady, MJ: AUTHOR [+2]

Abstract

A technique is described for electrically isolating metallization in a a groove. First, a metal layer is deposited over the entire surface. Then, the metallized grooves are filled with a resist or other etch-resistant flowing material using capillary flow action to keep the material in the grooves. Finally, the uncovered metal outside of the grooves is etched away.

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Capillary Masking of Topologically Etched Silicon Substrates

A technique is described for electrically isolating metallization in a a groove. First, a metal layer is deposited over the entire surface. Then, the metallized grooves are filled with a resist or other etch-resistant flowing material using capillary flow action to keep the material in the grooves. Finally, the uncovered metal outside of the grooves is etched away.

As described in more detail in (*), capillary flow of solder day be used to conveniently bond and simultaneously electrically connect a designated spot on a flipped-over chip to a substrate having suitable metallized grooves. It is particularly useful in bonding GaAlAs lasers to a silicon substrate. When more than one GaAlAs laser is to be bonded to the substrate, however, and electrical isolation is desired between lasers, there is a need for a convenient technique which will isolate the metallized grooves from each other.

We have demonstrated a technique which allows the planar metallurgy to be selectively removed, which eliminates electrical continuity between grooves (channels) while maintaining metallization within the bonding channel. Etched channels in the silicon substrate will fill with thinned photoresist or other materials such as waxes.

This filling is driven by the same capillary action as in the channel bonding. Preferential filling is enhanced when the surface tension of the filling material is large. The planar metallization l...