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Browse Prior Art Database

Reuseable Diffusion Capsule

IP.com Disclosure Number: IPCOM000074812D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Pak, MS: AUTHOR

Abstract

A capsule diffusion reuseable capsule is shown in Fig. 1. The capsule 10 which is typically made of quartz, may be attached to the tube 12 by a ground glass shoulder 11. Alternatively, the capsule may be in one piece 10, 12 and attached by a vacuum adapter 13 to glass tube 18, which in turn is held firm by a holder 14. The diffusion chamber 15 contains a plurality of wafers 16 in a suitable wafer boat 17. The diffusion chamber 15 is closed off by a vacuum gasket 19, such as a platinum foil, supported by a backing which could be a quartz plate 20. The backing plate 20 may be raised to the capsule sealing position by mechanical or magnetic means, not shown.

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Reuseable Diffusion Capsule

A capsule diffusion reuseable capsule is shown in Fig. 1. The capsule 10 which is typically made of quartz, may be attached to the tube 12 by a ground glass shoulder 11. Alternatively, the capsule may be in one piece 10, 12 and attached by a vacuum adapter 13 to glass tube 18, which in turn is held firm by a holder 14. The diffusion chamber 15 contains a plurality of wafers 16 in a suitable wafer boat 17. The diffusion chamber 15 is closed off by a vacuum gasket 19, such as a platinum foil, supported by a backing which could be a quartz plate 20. The backing plate 20 may be raised to the capsule sealing position by mechanical or magnetic means, not shown.

Processing wafers in the capsule diffusion structure is shown with the aid of Figs. 2 and 3. The capsule is cleaned, loaded with wafers, evacuated, and baked out in a furnace, as shown in Fig. 2, with the vacuum gasket 19 and backing plate 20 in their down position. The vacuum gasket 19 and vacuum plate 20 is then closed and atmospheric pressure applied to the area 18 behind the plate 20. At this point there is a vacuum within the area 15. The appropriate temperature by the furnace is then applied to the capsule 10 for sufficient time to diffuse the appropriate impurities from the source contained in the wafer boat 17 into the wafers 16. The region 18 is then evacuated, the vacuum gasket and vacuum plate moved to their down position and the wafers in the wafer boat unloaded from the c...