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Browse Prior Art Database

Method for Reducing Fencing and Skirting Effects in Liftoff Processes

IP.com Disclosure Number: IPCOM000047018D
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Graves, BL: AUTHOR

Abstract

This article describes a method for reducing metal fencing and skirting effects in lift-off processes by baking the photoresistcoated wafers prior to metal deposition at a temperature of about 100ŒC Å 3ŒC for 10 minutes at a vacuum of 5 x 10-5 Torr or lower. One mechanism that can cause severe metal fencing and skirting (unwanted metallic protrusions) is photoresist outgassing during the Al/Cu metal deposition. This causes metal vapors to scatter as they enter the resist liftoff structures and to form the unwanted metal fences and skirts. These defects can cause reliability problems in devices because they may result in the inadequate metal sidewall coverage, they may create unwanted electrical paths to exposed metal traces, they create potential traps for contaminants (e.g., acid, photoresist, foreign materials, etc.

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Method for Reducing Fencing and Skirting Effects in Liftoff Processes

This article describes a method for reducing metal fencing and skirting effects in lift-off processes by baking the photoresistcoated wafers prior to metal deposition at a temperature of about 100OEC Å 3OEC for 10 minutes at a vacuum of 5 x 10-5 Torr or lower. One mechanism that can cause severe metal fencing and skirting (unwanted metallic protrusions) is photoresist outgassing during the Al/Cu metal deposition. This causes metal vapors to scatter as they enter the resist liftoff structures and to form the unwanted metal fences and skirts. These defects can cause reliability problems in devices because they may result in the inadequate metal sidewall coverage, they may create unwanted electrical paths to exposed metal traces, they create potential traps for contaminants (e.g., acid, photoresist, foreign materials, etc.), and they add parasitic capacitance to devices. Baking the photoresist-coated wafers prior to metal deposition has been found to substantially reduce the photoresist outgassing and to eliminate most metal fencing and skirting effects.

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