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Self Aligned Oxide Filled Deep Shallow Trench Isolation with One Fill Planarization Step

IP.com Disclosure Number: IPCOM000109754D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 3 page(s) / 81K

Publishing Venue

IBM

Related People

Warnock, J: AUTHOR

Abstract

Disclosed is a process for shallow/deep trench isolation where the shallow trench is self-aligned to the deep trench, and both are filled and planarized simultaneously. This simultaneous fill and planarization results in a considerable reduction of the isolation process complexity.

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Self Aligned Oxide Filled Deep Shallow Trench Isolation with One Fill Planarization Step

       Disclosed is a process for shallow/deep trench isolation
where the shallow trench is self-aligned to the deep trench, and both
are filled and planarized simultaneously.  This simultaneous fill and
planarization results in a considerable reduction of the isolation
process complexity.

      The technique to be described yields a greatly simplified
isolation process, with an oxide-filled deep trench and a shallow
trench isolation which is self-aligned to the deep trench.  Also,
since the shallow and deep trenches are filled and planarized
simultaneously, any effects of the shallow trench processing on the
deep trench structure are minimized.  Present schemes for the
oxide-filled deep trench rely on a separate fill and planarization
process for the deep trench, followed subsequently by the shallow
trench processing.  Although these schemes provide oxide-filled deep
and shallow trench isolation, they require separate thick oxide
depositions for shallow and deep trenches, along with a rather
complicated planarization process after each deposition.  Also, one
has to worry about the effects of the shallow trench processing on
the deep trench structure (seams may be opened, oxidation may induce
stresses, etc.).

      The process disclosed here avoids the above difficulties, and
proceeds as follows.  A thin thermal pad oxide and CVD nitride are
patterned by RIE using t...