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Bonding Silicon Wafers to Headers

IP.com Disclosure Number: IPCOM000095881D
Original Publication Date: 1964-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Lia, R: AUTHOR [+2]

Abstract

Heretofore the operation of bonding silicon wafers to headers using gold or gold-silicon preforms between those two members, or the procedure of directly bonding the gold plated header to the silicon wafer has required twenty to thirty seconds. The steps set forth below permit a bonding of a wafer to a header in two seconds. 1. The collector surface of the wafer is roughened by lapping or vapor blasting. 2. That surface is cleaned by etching with hydrofluoric acid. 3. A gold film is evaporated on a cold substrate, i. e., with the latter at a temperature well below the eutectic temperature of the gold and the silicon. 4. A coating of sodium chloride or similar salt is evaporated over the gold film so as to prevent it from balling up in the subsequent alloying step. 5.

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Bonding Silicon Wafers to Headers

Heretofore the operation of bonding silicon wafers to headers using gold or gold-silicon preforms between those two members, or the procedure of directly bonding the gold plated header to the silicon wafer has required twenty to thirty seconds. The steps set forth below permit a bonding of a wafer to a header in two seconds. 1. The collector surface of the wafer is roughened by lapping or vapor blasting. 2. That surface is cleaned by etching with hydrofluoric acid. 3. A gold film is evaporated on a cold substrate, i. e., with the latter at a temperature well below the eutectic temperature of the gold and the silicon. 4. A coating of sodium chloride or similar salt is evaporated over the gold film so as to prevent it from balling up in the subsequent alloying step. 5. The gold film is alloyed with the wafer surface by heating to a temperature of 450-600 degrees C. 6. When the latter is completed, the salt coating is removed with a suitable solvent. 7. The gold alloyed surface of the wafer is then placed on the gold plated header and bonded to it at a temperature of about 400 degrees C.

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