Browse Prior Art Database

Uniform Cooling Oxidation Boat in a Diffusion Capsule

IP.com Disclosure Number: IPCOM000076342D
Original Publication Date: 1972-Feb-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Brack, K: AUTHOR [+5]

Abstract

This diffusion capsule permits cooling of an impurity source at a rate different from that of the wafer boat, thereby preventing scattering of the source powder and diminishing the condensation of impurity powder on the wafers being diffused.

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Uniform Cooling Oxidation Boat in a Diffusion Capsule

This diffusion capsule permits cooling of an impurity source at a rate different from that of the wafer boat, thereby preventing scattering of the source powder and diminishing the condensation of impurity powder on the wafers being diffused.

The diffusion capsule 10 of the Figure is formed into two sections 11 and 12, by reducing the capsule at its central point 13. In one section, i.e. section 11, there is disposed the source boat 14 containing a powdered impurity to be diffused into the wafer. The other section 12 contains a wafer boat 15, which is loaded with a plurality of wafers 16. This wafer boat 15 is formed such that a substantially uniform circumferential heat mass surrounds the wafers 16 so that the wafers 16 will cool symmetrically.

Because the source boat 14 is removed from the wafer boat 15, it can be separately cooled at a rate different from the cooling rate of the wafer boat. This separate cooling reduces the impurity condensation on the wafers and eliminates the scattering of source powder. The boat permits a separate slow cooling of the wafers, thus eliminating process induced slip. The wafer boat can also be used for the subsequent reoxidation process.

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