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Metallic Free Organic Aluminum Etchant

IP.com Disclosure Number: IPCOM000077135D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 20K

Publishing Venue

IBM

Related People

Hoeg, AJ: AUTHOR [+3]

Abstract

High-viscosity etchants for aluminum films such as phosphoric, nitric and acetic acid mixtures are quenched by entrapment of gaseous products on the surface of the film. Difficulty is also encountered in spray etching with highly-viscous solutions due to nozzle clogging.

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Metallic Free Organic Aluminum Etchant

High-viscosity etchants for aluminum films such as phosphoric, nitric and acetic acid mixtures are quenched by entrapment of gaseous products on the surface of the film. Difficulty is also encountered in spray etching with highly- viscous solutions due to nozzle clogging.

A low viscosity etchant for aluminum which overcomes the above difficulties is provided by solutions of organic amines in water. The etchant is an organic secondary amine R' NX-R'' such as piperidine or pyrrolidine

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where R' and R'' can be alkane, alkene, or aromatic derivatives. These materials form basic solutions of ph8-14 depending on the percentage of amine. A ph of 12.5 for etching aluminum with KTFR* photoresist or AZ-111'' and AL- 1350'' photoresists is provided by a 0.05 weight/volume composition with water.

The etchant is metallic free and the etchant liquid can be recycled from the etch bath by azeotropic distillation. Other metallic films or semiconductor substrates which etch in basic (alkali) media could be etched with this composition, since the etchant is volatile in both components (water and piperidine). No residues are left after drying. * Product of Eastman Kodak Company ** Trademark of Shipley Company, Inc.

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