Browse Prior Art Database

Capsule Spacer for Semiconductor Device Fabrication

IP.com Disclosure Number: IPCOM000086939D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Gordon, BM: AUTHOR

Abstract

This reusable capsule spacer 10 prevents undesirable movement of the end plug in a diffusion "capsule set" and assures a uniform diffusion capsule volume from run to run.

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Capsule Spacer for Semiconductor Device Fabrication

This reusable capsule spacer 10 prevents undesirable movement of the end plug in a diffusion "capsule set" and assures a uniform diffusion capsule volume from run to run.

A capsule set comprises a tubular capsule body member 12 having one end closed in a hemispherical configuration and an end plug 14 which comprises a similar hemispherically capped tubular member loosely fitting within the capsule
12.

In semiconductor device fabrication, a diffusion step is performed by enclosing a "boat" 16 carrying a multiple of doped silicon or other type wafers 18 and a charge of "source powder" 20 in a capsule set and evacuating the set by means of a vacuum pump connected by a chuck at the open end 22 of the capsule body member 12. When the desired vacuum exists within the capsule, the body member 12 and the end plug 14 are heated circumferentially until the two are fused or welded together in a vacuum-tight seal. The charged capsule is then removed and transported to the next work station.

Movement of the end plug 14 within the capsule, which permits the final volume to vary and/or the disturbance of the source powder which frequently causes it to fly all over, is prevented by the spacer 10. This spacer comprises a quartz spacing rod 26 and an end piece 28 which are fused together. The end piece is readily made of another end plug by opening several large holes 30 in the end piece portion, whereby there is a free passage f...