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Reworked Device Contacts

IP.com Disclosure Number: IPCOM000046620D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

DiAngelo, DW: AUTHOR [+4]

Abstract

A reworked device contact procedure is described whereby device contacts inadvertently exposed to atmosphere during an evaporation cycle are reconditioned to suitable contact resistances. Inadvertent atmosphere exposure caused by evaporator or tool malfunction generally results in high device contact resistances or high Schottky barrier diode forward voltage drops. This results in scrapping these wafers. The proposed rework procedure is as follows: (1) After inadvertent exposure, remove wafers from evaporator and, if necessary, remove all lift-off photoresist to decrease chances of resist flow and/or resist redeposit in contact. (2) After resist stripping, pump down to 2 x 10-6 Torr and backfill in argon (2 x 10-4 Torr). Subject wafer to ion milling process at a beam current of 2.

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Reworked Device Contacts

A reworked device contact procedure is described whereby device contacts inadvertently exposed to atmosphere during an evaporation cycle are reconditioned to suitable contact resistances. Inadvertent atmosphere exposure caused by evaporator or tool malfunction generally results in high device contact resistances or high Schottky barrier diode forward voltage drops. This results in scrapping these wafers. The proposed rework procedure is as follows: (1) After inadvertent exposure, remove wafers from evaporator and, if necessary, remove all lift-off

photoresist to decrease chances of resist flow and/or

resist redeposit in contact. (2) After resist stripping, pump down to 2 x 10-6 Torr and backfill in argon (2 x 10-4 Torr). Subject wafer to

ion milling process at a beam current of 2.0 milliamps

for about 2-8 minutes to remove chrome oxide and/or Al-Cu.
(3) Reprepare lift-off photoresist, etc., and then

redeposit metal.

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