At&t Bell Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Nun-Sian Tsai

Chih-Yuan Lu

Min-Liang Chen

Virendra V Rana

Chung W Leung

Robert D Huttemann

In the manufacture of an integrated-circuit device, periodic interruption of grain growth during chemical vapor deposition of a metal film results in enhanced surface smoothness and ease of patterning. Interruption of grain growth is by deposition of an auxiliary material which, in the interest of high conductivity of the film, may be conductive, may form a conductive compound or alloy, or may be eliminated upon additional metal deposition. When the metal is tungsten, silicon is a preferred grain-growth interrupting material.

Process for making integrated-circuit device metallization

A metallization scheme useful for integrated circuits uses a buffer layer to ensure that the etch back of a contact metal, such as tungsten, deposited over the buffer layer, can be controlled to form a complete tungsten plug in a via while the tungsten on the dielectric is completely removed. The buffer layer, once exposed, reacts with the plasma etch to form non-volatile compounds which decrease the free surface mobility of the etching species. This active species depletion thus decreases the etch rate of the tungsten within the vias. Continued exposure of unreacted buffer material is ensured by performing a sputter cleaning simultaneously with the plasma etch.

Semiconductor device having tungsten plugs

Silicides are important for submicron VLSIC technology. Problems have been found in forming silicides by known techniques involving simply depositing a metal film and heating that metal to form a silicide layer. This invention solves the problems through recognition that polymeric contamination can be left on the surface from commonly-used previous reactive ion etch steps, and removes any such contamination to metal deposition by the additional step of heating in dry oxygen at a low temperature, such as 800 degrees Centigrade, before the contamination has been significantly hardened.

Growing community of inventors

South Whitehall, PA, United States of America

Nun-Sian Tsai