Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Patent
1995-04-18
1998-07-28
Everhart, Caridad
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
438714, 438644, 438656, 438672, H01L 2144
Patent
active
057862729
ABSTRACT:
A plug contact process wherein, after contact holes are etched, an adhesion layer (such as Ti/TiN) and a filler metal (such as tungsten) are deposited overall. A two-stage etch is then used: First, the filler metal is etched preferentially with respect to the adhesion layer, until an endpoint signal first indicates that said adhesion layer is exposed. No overetch is used at this stage. Thereafter a nonpreferential etch is used to clear residues of the filler metal, while also uniformly reducing the height of the adhesion layer. This prevents the tops of the plugs in the contact holes from being recessed. Aluminum (or other metal) is then deposited and patterned (using a stack etch to remove the undesired portions of the adhesion layer too) to implement the desired wiring pattern. This process thereby reduces voids, and resulting metallization defects, in a process with high-aspect-ratio contacts. In addition, the residual adhesion layer helps to reduce electromigration.
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P. Riley et al., "Implementation of Tungsten Metallization in Multilevel Interconnection Technologies" IEEE Transactions on Semiconductor Manufacturing, vol. 3, No. 4, Nov. 1990, pp. 150-157.
J. Theisen et al., "Maskless Tungsten Etch Process for Plug Fill" Extended Abstracts, vol. 90-1, No. 165, 1990, Princeton, NJ, pp. 248-249.
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K. Koller et al "Tungsten Plug Formation by an Optimized Tungsten Etch Back Process in Non-Fully Planarized Topology" Applied Surface Science (Month Unknown 1991) pp. 54-61.
Desanti Giorgio
Marangon Maria Santina
Marmiroli Andrea
Carlson David V.
Everhart Caridad
Santarelli Bryan A.
SGS--Thomson Microelectronics S.r.l.
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