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An Enhanced Borderless Contact Process

IP.com Disclosure Number: IPCOM000108423D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 70K

Publishing Venue

IBM

Related People

Bartush, T: AUTHOR [+4]

Abstract

A borderless contact process for the diffusion and gate contact windows depends on the etch selectivities of the bulk passivation material (or polysilicon in a sacrificial structure) to both the masking material and the underlying borderless contact stop layer. The diffusion and gate contact windows must be borderless to achieve the required circuit wiring density for ULSI technologies.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

An Enhanced Borderless Contact Process

      A borderless contact process for the diffusion and gate contact
windows depends on the etch selectivities of the bulk passivation
material (or polysilicon in a sacrificial structure) to both the
masking material and the underlying borderless contact stop layer.
The diffusion and gate contact windows must be borderless to achieve
the required circuit wiring density for ULSI technologies.

      A contact window formation process that significantly improves
the etch selectivity of the passivation material to the masking layer
has been developed.  Consequently, this contact window formation
process eliminates the problem of contact window beveling or
broadening that occurs because of the erosion of the mask layer
during the contact etch. Additionally, the contact stud height is
increased because of the reduced mask erosion.  The process begins
following the deposition of the normal contact mask oxide layer.  A
50 nm layer of CVD aluminum oxide (AlOx) is deposited on top of the
mask oxide layer.  The diffusion contact window level is patterned
using photolithography.  The photoresist mask is transferred into the
AlOx layer with a BC13 based Reactive Ion Etch (RIE) process.  With
the photoresist mask still in place, a fluorine-based RIE process is
used to transfer the pattern into the mask oxide layer.  The
photoresist mask is then removed.  The normal contact etch process is
used for the remainder of the etch process....