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Improved Stud Shape by Auto-Multi-Damascene Process

IP.com Disclosure Number: IPCOM000100638D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Cronin, JE: AUTHOR [+4]

Abstract

By reusing an etched back photoresist image in making mold shapes in damascene conductor formation (auto-multi-damascene or AMD process), studs are formed having larger tops than bottoms. This shape has advantages especially in connecting from narrow, high density lines on a lower level to wider, lower density lines in an upper level of wiring.

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Improved Stud Shape by Auto-Multi-Damascene Process

       By reusing an etched back photoresist image in making
mold shapes in damascene conductor formation (auto-multi-damascene or
AMD process), studs are formed having larger tops than bottoms.  This
shape has advantages especially in connecting from narrow, high
density lines on a lower level to wider, lower density lines in an
upper level of wiring.

      Referring to Fig. 1, a stud is to be connected from conductive
line 10 on substrate 12 through an insulator, e.g., polyimide 14.
Etch stop material, e.g., siloxane, is first deposited and a
photoresist layer 18 is defined having an opening of diameter W.
Exposed etch stop layer 16 is removed by anisotropic etching and then
polyimide 14 is also etched anisotropically until the top surface of
line 10 is exposed. Photoresist 18 is thinned and etched back from
its initial shape (shown in dashed outline).

      Referring to Fig. 2, newly exposed etch stop 16 is etched off
and polyimide 14 is anisotropically etched to a depth d which may be
well defined by having another etch stop layer at that depth or may
be defined as the point at which polyimide etching is stopped by time
control. Photoresist is completely removed during the polyimide
etching process.  Damascene formation of stud 20 is then completed by
conformal deposition of a conductor and planarizing to expose etch
stop 16.