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Browse Prior Art Database

Trench Cap Formation

IP.com Disclosure Number: IPCOM000040879D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Arienzo, M: AUTHOR [+2]

Abstract

Silicon-filled trenches for bipolar device isolation can be mo reliably and simply capped beneath crossing metal conductors by forming the cap with tetraethoxysilane (TEOS) oxide.

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This is the abbreviated version, containing approximately 100% of the total text.

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Trench Cap Formation

Silicon-filled trenches for bipolar device isolation can be mo reliably and simply capped beneath crossing metal conductors by forming the cap with tetraethoxysilane (TEOS) oxide.

After a trench is lined with a silicon dioxide/nitride composite and filled with either epitaxial silicon or polysilicon, the subsequent planarization leaves the silicon slightly below the wafer surface. The trench silicon is further slightly recessed up to a half micron depending on trench width. Oxide by the TEOS process is added to the trench silicon and any excess is removed down to the nitride layer on the device surface.

The formed trench cap does not have a closing seam due to its smaller thickness relative to half the trench width. Subseque annealing at 900oC in steam densifies the TEOS and grows oxide beneath it. The oxide can be grown to the necessary thickness without inherent stress that accompanies other processes Trench sides are protected from further oxidation by a nitride layer in the previously formed side wall so that this cap can be used where device structures butt the trench.

Disclosed anonymously

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