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Diffusion Capsule Equipped with a Venting Capillary

IP.com Disclosure Number: IPCOM000082303D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Malin, K: AUTHOR [+2]

Abstract

By use of a capillary fused to its seal cap, an evacuated and sealed diffusion capsule can be vented slowly.

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Diffusion Capsule Equipped with a Venting Capillary

By use of a capillary fused to its seal cap, an evacuated and sealed diffusion capsule can be vented slowly.

Diffusion capsule 1 for this method of controlled venting differs from a conventional diffusion capsule in that a piece of a capillary quartz tube 2, having a very small inner diameter, is fused at one of its ends to the bottom of seal cap 3, which in that spot has a hole extending into the quartz tube. The other end of the capillary quartz tube 2 is sealed.

After diffusion, the sealed end of the capillary quartz tube 2 is broken off, rather than venting the evacuated capsule 1 by drilling a hole into its wall. This causes the air to flow slowly through the capillary into the capsule 1, without disturbing the source powder 4, thus preventing wafers 5, which have been subjected to the diffusion process, from being contaminated by the powder 4. After pressure balance has been reached, the capsule 1 can be opened in the conventional way.

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