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Gas Injector for Nitride Deposition Using 2% Silane Gas

IP.com Disclosure Number: IPCOM000047822D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Gallagher, JP: AUTHOR [+2]

Abstract

Described is an improved design for a gas injector for providing uniform gas distribution under high flow rates to wafers on a wafer carrier. Good safety practices militate against the use of 100% silane. However, when the silane is reduced to 2% or less, very high flow rates are required in order to achieve the same uniformity in the nitride films. A commercially available Plasma Enhanced Chemical Vapor Deposition (PECVD) nitride tool was modified by providing a flat platen carrying the wafers which closely surround a gas injector having a conical anemostat-like structure for producing a laminar flow over the wafers. The original equipment injector shown in Fig. 1 consists of the entry port 10 formed in a flanged member 11 having three upstanding pillars 11A, 11B and 11C secured thereto.

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Gas Injector for Nitride Deposition Using 2% Silane Gas

Described is an improved design for a gas injector for providing uniform gas distribution under high flow rates to wafers on a wafer carrier. Good safety practices militate against the use of 100% silane. However, when the silane is reduced to 2% or less, very high flow rates are required in order to achieve the same uniformity in the nitride films. A commercially available Plasma Enhanced Chemical Vapor Deposition (PECVD) nitride tool was modified by providing a flat platen carrying the wafers which closely surround a gas injector having a conical anemostat-like structure for producing a laminar flow over the wafers. The original equipment injector shown in Fig. 1 consists of the entry port 10 formed in a flanged member 11 having three upstanding pillars 11A, 11B and 11C secured thereto. A flat plate 12 is secured to the end of the pillars to direct the high velocity gas entering the port 10 radially outward. The first plate, however, produces a turbulent flow, resulting in uneven gas distribution to the wafers and a consequent non-uniformity in the coating. By substituting a conical cap 13 (as shown in Fig. 2) or a cissoid-shaped cap 14 (as shown in Fig. 3) the direction of the gas flow from vertical to radial is non-turbulent and laminar. This provides a uniform gas distribution to the wafers, acting somewhat like an inverted anemostat.

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