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Recovering Semiconductor Waste Material

IP.com Disclosure Number: IPCOM000093197D
Original Publication Date: 1967-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Dessauer, RG: AUTHOR [+3]

Abstract

This technique recovers semiconductor waste material that is scrapped or discarded from semiconductor processing operations. Scrap semiconductor material, like silicon, is fed at a constant weight rate into one end of a water-cooled melting boat. The boat is located in a quartz tube that is exposed to an inert gas atmosphere. An RF coil surrounds the quartz tube and boat. A previously prepared length of ingot extends from the molten zone under the coil out of the other end of the boat and tube.

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Recovering Semiconductor Waste Material

This technique recovers semiconductor waste material that is scrapped or discarded from semiconductor processing operations. Scrap semiconductor material, like silicon, is fed at a constant weight rate into one end of a water- cooled melting boat. The boat is located in a quartz tube that is exposed to an inert gas atmosphere. An RF coil surrounds the quartz tube and boat. A previously prepared length of ingot extends from the molten zone under the coil out of the other end of the boat and tube.

The bar is withdrawn, slowly, at constant speed by a set of motor driven friction wheels. The molten material freezes into an ingot as it is drawn out of the molten zone. This ingot is substantially free of impurities due to the tendency of the impurities to remain in the liquid rather than the solid state of silicon. The bar can be cut off periodically by a moveable clamp and cutting wheel mechanism.

During the process, a zone refining effect occurs due to the segregation coefficient of silicon. Constant feed of the irregular sized scrap silicon can be achieved by use of a load cell and integrating device controlling the conveyor belt speed. This technique continuously converts scrap silicon to usable charges with a minimum of operator supervision.

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