Browse Prior Art Database

In Situ Deposition, Planarization, And Etching of Polysilicon

IP.com Disclosure Number: IPCOM000099946D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Dobuzinsky, D: AUTHOR [+4]

Abstract

A narrow trench having oxide-lined sidewalls is first filled with polysilicon, then planarized, and finally etched back such that it is recessed below oxide surfaces. Planarization is aided and process time is minimized by the deposition and reflow of boron oxide (B2O3). All of this processing is performed without removal from a vacuum- sealed multi-station processor.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

In Situ Deposition, Planarization, And Etching of Polysilicon

       A narrow trench having oxide-lined sidewalls is first
filled with polysilicon, then planarized, and finally etched back
such that it is recessed below oxide surfaces. Planarization is aided
and process time is minimized by the deposition and reflow of boron
oxide (B2O3).  All of this processing is performed without removal
from a vacuum- sealed multi-station processor.

      Referring to Fig. 1, a trench is cut in silicon substrate 10
and sidewalls are lined with silicon dioxide (SiO2) 12.  Surfaces
adjacent the trench are covered with SiO2 14.  Polysilicon 16
partially fills the trench and sidewall insulation SiO2 18 completes
the cross section shown in Fig. 1, which is the starting condition
for this process.

      Referring to Fig. 2, polysilicon 20 is deposited by chemical
vapor deposition (CVD) to a thickness sufficient to totally fill the
trench.  Then B2O3 22 is plasma deposited and reflowed.

      Referring to Fig. 3, a reactive ion etching process, which
removes B2O3 and polysilicon at the same rate and will not attack
SiO2, is used to create the flat surface of polysilicon 20 which is
recessed below the oxide surface levels as shown.