Browse Prior Art Database

Fine Grain CVD W Film Produced by Modulating Reactor Gasses

IP.com Disclosure Number: IPCOM000040655D
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Lee, PP: AUTHOR

Abstract

A dynamic chemical vapor deposition (CVD) process is reported for VLSI semiconductor fabrication, allowing film properties to be controlled by process parameters including the deposition duty cycle, gas ratio, temperature and pressure. By modulating the gas flow in a CVD reactor, a fine grained tungsten film is formed with an average surface roughness of 4% which eliminates lithographic imaging problems. The new process reduces void formation for better hole fill. Moreover, the deposition rate is significantly increased. Dynamic deposition is carried out utilizing one of the methods shown in Fig. 1. The first method shown in Fig. 1a starts with the introduction of a constant flow of hydrogen (H2) and silane mixture (SiH4). Tungsten hexaflouride (WF6) is modulated to create a certain duty cycle.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 83% of the total text.

Page 1 of 2

Fine Grain CVD W Film Produced by Modulating Reactor Gasses

A dynamic chemical vapor deposition (CVD) process is reported for VLSI semiconductor fabrication, allowing film properties to be controlled by process parameters including the deposition duty cycle, gas ratio, temperature and pressure. By modulating the gas flow in a CVD reactor, a fine grained tungsten film is formed with an average surface roughness of 4% which eliminates lithographic imaging problems. The new process reduces void formation for better hole fill. Moreover, the deposition rate is significantly increased. Dynamic deposition is carried out utilizing one of the methods shown in Fig. 1. The first method shown in Fig. 1a starts with the introduction of a constant flow of hydrogen (H2) and silane mixture (SiH4). Tungsten hexaflouride (WF6) is modulated to create a certain duty cycle. The magnitude of modulation is a key factor in this CVD process. Fig. 1b shows a method where a constant flow of hydrogen is used while modulating the flow of silane and tungsten hexaflouride. A third method is shown in Fig. 1c which uses a constant flow of hydrogen, eliminates the silane mixture and modulates the tungsten hexaflouride flow. The duty cycle and gas ratio can be adjusted to obtain an optimal deposition rate and film composition. Resistivity (grain size) and surface roughness is controlled by adjusting process parameters. Fig. 2 shows the deposition rate of modulated and non-modulated WF6 . At 450 de...