Browse Prior Art Database

Hot Process Tube

IP.com Disclosure Number: IPCOM000035977D
Original Publication Date: 1989-Aug-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Bauer, HJ: AUTHOR [+2]

Abstract

A quartz tube for hot processing is modified to reduce the exchange of hot gas and ambient air during wafer loading. This modification maintains an inert gas atmosphere in the tube, for example, for the silicide formation of metals which oxidize easily when heated.

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Hot Process Tube

A quartz tube for hot processing is modified to reduce the exchange of hot gas and ambient air during wafer loading. This modification maintains an inert gas atmosphere in the tube, for example, for the silicide formation of metals which oxidize easily when heated.

The diameter of the tube is reduced slightly at "A" to accommodate a baffle mounted on two cantilever rods. The two rods ride on rails outside the furnace and transport the wafers into and out of the furnace. Movement of the cantilever rods through the end cap without friction is accomplished by feedthroughs the diameter of which is slightly larger than that of the cantilever rods. To prevent the air from streaming back through clearance gaps, the feedthroughs are especially designed and purged with an inert gas.

The end cap is opened for a short time, typically less than a minute, during wafer loading. It moves on the same rails as the cantilever rods but separately thereof. Hot gas is kept in the process zone, as the baffle closes the tube at "A". During loading, ambient air may enter the loading zone but not the process zone.

After wafer loading, the baffle remains in that position for about 10 minutes to purge any ambient air from the loading zone. After this time, the cantilever rods move into the furnace and transport the wafers into the process zone.

The surfaces of the baffle and the end cap are ground to scatter radiated heat. The ground surfaces keep the wafers cool during pu...