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Damascene Process for Simultaneously Inlaying Tungsten Into Lines and Contacts

IP.com Disclosure Number: IPCOM000122351D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Cote, WJ: AUTHOR [+4]

Abstract

By the use of a unique process, one tungsten (W) deposition fills both contact holes and lines defined in an insulator. The process results in the ability to make a density of W lines much greater than previously possible.

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Damascene Process for Simultaneously Inlaying Tungsten Into Lines
and Contacts

      By the use of a unique process, one tungsten (W)
deposition fills both contact holes and lines defined in an
insulator. The process results in the ability to make a density of W
lines much greater than previously possible.

      Fig. 1 shows a cross-section of a starting condition wherein
recessed oxide (ROX) 10 is formed in silicon substrate 12.
Polysilicon line 14 is formed on ROX 10 and covered first with a
reflowed oxide 16 and then a planarized pyrolytic oxide 18.

      The cross-section shown in Fig. 2 is obtained by defining
contact holes and anisotropically etching part way through oxide
layers 16 and 18, then defining a W line pattern and again etching to
form the line pattern profile and to remove the rest of the oxides 16
and 18 to expose the contacts to line 14 and substrate 12.

      Referring to Fig. 3, titanium and titanium nitride are formed
on exposed silicon (not shown) and W is deposited, and an oxide 22 is
applied and polished back to protect large area W regions while
planarizing by anisotropic etching and then polishing.  The final
result of this process is shown in Fig. 4.

      A variation in the process is to etch the contact holes all the
way through insulators 16 and 18.  Then, partially fill the contact
holes with an organic insulator by over-filling the holes and then
anisotropically etching back.  After doing the line pattern etch, th...