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Contact Resistance Improvement for Tungsten Metallurgy

IP.com Disclosure Number: IPCOM000099348D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 1 page(s) / 34K

Publishing Venue

IBM

Related People

Hartswick, TJ: AUTHOR [+3]

Abstract

By first sputter depositing titanium (Ti) and then reactively sputter depositing titanium nitride (TiN) before depositing tungsten (W) by chemical vapor deposition (CVD), good adhesion of W to insulators is maintained and improved contact resistance is achieved between the W and underlying conductor exposed in via holes. The composite Ti plus TiN interface layer is achieved without any high temperature heat treatment required.

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Contact Resistance Improvement for Tungsten Metallurgy

       By first sputter depositing titanium (Ti) and then
reactively sputter depositing titanium nitride (TiN) before
depositing tungsten (W) by chemical vapor deposition (CVD), good
adhesion of W to insulators is maintained and improved contact
resistance is achieved between the W and underlying conductor exposed
in via holes.  The composite Ti plus TiN interface layer is achieved
without any high temperature heat treatment required.

      Referring to the figure, insulating layer 2 on substrate 4 has
a via hole having diameter A exposing underlying conductor 6.  Pure
metal Ti 8 is next deposited by sputtering in a noble gas.  By adding
nitrogen (N) to the sputtering environment, TiN 10 is then deposited.
 The cross section shown in the figure is completed by conventional
deposition of W 12 by CVD and W wiring pattern definition followed by
etching away exposed TiN and Ti.  Conventional processing is used to
complete an integrated circuit.

      Contact resistance between W 12 and underlying conductor 6 is
low and adhesion of the conductive line composite Ti 8 - TiN 10 - W
12 to insulator 2 is excellent.