Use of enhanced turbomolecular pump for gapfill deposition using high flows of low-mass fluent gas

Abstract

High flows of low-mass fluent gases are used in an HDP-CVD process for gapfill deposition of a silicon oxide film. An enhanced turbomolecular pump that provides a large compression ratio for such low-mass fluent gases permits pressures to be maintained at relatively low levels in a substrate processing chamber, thereby improving the gapfill characteristics.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a divisional of U.S. patent application Ser. No. 10 / 884,628, entitled “USE OF ENHANCED TURBOMOLECULAR PUMP FOR GAPFILL DEPOSITION USING HIGH FLOWS OF LOW-MASS FLUENT GAS,” filed Jul. 1, 2004 by Muhammad M. Rasheed, the entire disclosure of which is incorporated herein by reference for all purposes.BACKGROUND OF THE INVENTION [0002] One of the primary steps in the fabrication of modern semiconductor devices is the formation of a film, such as a silicon oxide film, on a semiconductor substrate. Silicon oxide is widely used as an insulating layer in the manufacture of semiconductor devices. As is well known, a silicon oxide film can be deposited by a thermal chemical-vapor deposition (“CVD”) process or by a plasma-enhanced chemical-vapor deposition (“PECVD”) process. In a conventional thermal CVD process, reactive gases are supplied to a surface of the substrate, where heat-induced chemical reactions take place to produc...

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Benefits of technology

[0007] Embodiments of the invention make use high flows of low-mass fluent gases in an HDP-CVD process for gapfill deposition of a silicon oxide film. An enhanced turbomolecular pump that provides a large compression ratio for such low-mass fluent gases permits pressures to be maintained at relatively low levels in a substrate processing chamber, thereby improving the gapfill characteristics.

[0013] Embodiments of the invention also provide a method for upgrading a semiconductor processing facility to accommodate a high-density-plasma deposition process that uses a flow of a gas having an average molecular mass less than 10 amu at a rate that exceeds 400 sccm. The semiconductor processing facility includes a high-density-plasma substrate processing system that has a substrate processing chamber in fluid communication with a turbomolecular pump, a rough pump, and a foreline. The turbomolecular pump controls a pressure inside the substrate processing chamber. The rough pump provides a pressure intermediate between a desired operational pressure and atmospheric pressure. The foreline provides fluid communication between the turbomolecular pump and the rough pump. A pressure inside the substrate processing chamber during the high-density-plasma deposition process is determined. The foreline is reconfigured to reduce a pressure at an outlet of the turbomolecular pump to the foreline. The pressure inside the substrate processing chamber during the high-density-plasma process is consequently reduced.

[0014] The foreline may be reconfigured by increasing a diameter of at least a portion of the foreline, by reducing a number of bends comprised by the foreline, and the like. In one embodiment, the method further comprises upgrading a flow capacity of the rough pump.

Problems solved by technology

One persistent challenge faced by semiconductor manufacturers in the design and fabrication of such densely packed integrated circuits is the desire to prevent spurious interactions between circuit elements, a goal that has required ongoing innovation as geometry scales continue to decrease.

High-aspect-ratio gaps are difficult to fill completely using conventional CVD techniques, which tend to have relatively poor gapfill abilities.

Semiconductor manufacturers discovered, however, that there is a practical limit to the aspect ratio of gaps that HDP-CVD films are able to fill.

It has been reported that when such a process is used to fill certain narrow-width, high-aspect-ratio gaps, the sputtering caused by the argon in the process gas may hamper gapfill efforts.

This, in turn, may result in the formation of a void in the gap if the upper areas of regrowth join before the gap is completely filled.

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