Browse Prior Art Database

Dielectric Isolation

IP.com Disclosure Number: IPCOM000045069D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Riseman, J: AUTHOR

Abstract

Deep dielectric isolation regions in a monocrystalline silicon substrate substrate are achieved by first forming trenches using reactive ion etching and then filling these trenches with a glass having a coefficient of thermal expansion closely matching that of the silicon substrate. Deposition Deposition of glass particles can be by sedimentation, centrifugation or spin-on techniques. The structure is then fired until the glass particles fuse into a continuous glass layer. The structure then has to be planarized with the removal of substantially all of the glass above the surface of the silicon substrate.

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Dielectric Isolation

Deep dielectric isolation regions in a monocrystalline silicon substrate substrate are achieved by first forming trenches using reactive ion etching and then filling these trenches with a glass having a coefficient of thermal expansion closely matching that of the silicon substrate. Deposition Deposition of glass particles can be by sedimentation, centrifugation or spin-on techniques. The structure is then fired until the glass particles fuse into a continuous glass layer. The structure then has to be planarized with the removal of substantially all of the glass above the surface of the silicon substrate.

The overall process for forming such a dielectric isolation structure is as follows: (1) Provide a silicon dioxide coating upon a silicon wafer of about 200 to 400 nanometers. Use conventional lithography techniques to form openings in the silicon dioxide coating where isolation trenches are desired. (2) Reactive ion etch deep trenches into the silicon wafer using the silicon dioxide mask. (3) Oxidize the trench surfaces to form a SiO(2) layer thereon. (4) The trenches are filled with glass. A glass-ceramic or polycrystalline silicon material is included within the term glass. The material is selected to match the coefficient of thermal expansion of the silicon. Glass can be applied from a colloidal suspension by centrifugation, sedimentation or spin-on. (5) The wafer is mounted upon a standard polishing machine which is used to polish wafer...