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Browse Prior Art Database

Submicron Trench Filling

IP.com Disclosure Number: IPCOM000102236D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Pogge, HB: AUTHOR

Abstract

Advanced device isolation for high density device designs depends on deep narrow trench isolation, preferably filled with a dielectric material. Extensive data relative to SiO2-filled trenches reveal a region of "poor" quality SiO2 in the area where the two sides of the CVD SiO2 film meet each other. This occurs all along the depth of the trench, except for the top of the trench.

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Submicron Trench Filling

       Advanced device isolation for high density device designs
depends on deep narrow trench isolation, preferably filled with a
dielectric material.  Extensive data relative to SiO2-filled trenches
reveal a region of "poor" quality SiO2 in the area where the two
sides of the CVD SiO2 film meet each other.  This occurs all along
the depth of the trench, except for the top of the trench.

      Si3N4 CVD films do not exhibit this characteristic. Instead, a
very uniform and conformal deposition occurs throughout the depth of
the trench, so that the trench is efficiently filled up with good
quality Si3N4 throughout. However, due to excessive stress
generation, Si3N4 is not acceptable for complete trench filling.

      To assure good trench filling with the preferred dielectric
(SiO2), the preferred process procedure is as follows:  Assure a
slightly tapered trench geometry which is to be filled with the
dielectric film.  Initiate the trench filling with SiO2, using one of
several SiO2 source options. At predetermined regular intervals (the
specifics depend on the trench width) introduce, in addition to SiO2,
Si3N4 . This sequence of pulsing in Si3N4 will allow (or correct) for
more uniform deposition down the length of the trench, thereby
assuring proper trench filling.  The pulsing is done to allow for
tolerance variations of the trench width.  The pulsing of Si3N4 could
also be done without simultaneous deposition of SiO2, if so...