Browse Prior Art Database

Removal of Aluminum After a Lift Off Process

IP.com Disclosure Number: IPCOM000079439D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Palagonia, AM: AUTHOR

Abstract

In fabrication of integrated circuit metallurgy, it is a common practice to deposit a layer of aluminum, remove the desired metallurgy pattern in the aluminum by photolithographic techniques, deposit a blanket layer of the metal as for example layers of chromium, silver, and chromium, and subsequently remove the aluminum and the overlying chrome, silver, chrome layer. A basic solution is used to remove the aluminum, since acidic solutions may attack the metallurgy. Sodium hydroxide solutions have been used but have not been satisfactory, because of the possibility of sodium ion contamination.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Removal of Aluminum After a Lift Off Process

In fabrication of integrated circuit metallurgy, it is a common practice to deposit a layer of aluminum, remove the desired metallurgy pattern in the aluminum by photolithographic techniques, deposit a blanket layer of the metal as for example layers of chromium, silver, and chromium, and subsequently remove the aluminum and the overlying chrome, silver, chrome layer. A basic solution is used to remove the aluminum, since acidic solutions may attack the metallurgy. Sodium hydroxide solutions have been used but have not been satisfactory, because of the possibility of sodium ion contamination.

In this technique, the aluminum layer and the overlying metallurgy layer is removed with a solution of tetramethylarmonium hydroxide. This solution can be conveniently prepared by adding a pound of pentahydrate in a liter of water.

1