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Pattern Formation by Aluminum Anodization

IP.com Disclosure Number: IPCOM000094699D
Original Publication Date: 1965-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Kaplan, LH: AUTHOR

Abstract

The technique chemically etches thin aluminum film 1 supported on substrate 3. In normal photoresist processes, incomplete adhesion between the photoresist pattern and a thin metallic film allows penetration of the etching solution along the interface and results in poorly-defined etched metallic patterns.

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Pattern Formation by Aluminum Anodization

The technique chemically etches thin aluminum film 1 supported on substrate 3. In normal photoresist processes, incomplete adhesion between the photoresist pattern and a thin metallic film allows penetration of the etching solution along the interface and results in poorly-defined etched metallic patterns.

As in A, photoresist pattern 5 is initially formed over thin film 1 as a negative of the desired pattern, i.e., protecting portions of film 1 to be etched. Portions of film 1 exposed through pattern 5 are anodized by well-known techniques to form a thin aluminum oxide film which defines a final chemical etch mask 7. The anodization technique employed is compatible with the photoresist material of pattern 5. This is then stripped and exposed portions of film 1 are etched by an appropriate solution, e.g., ferric chloride.

Aluminum oxide mask 7 is removed by appropriate solvent, e.g., phosphoric acid (H(3)PO(4)) to expose aluminum pattern 1A as in B. The adhesion of film 7 to film 1 exceeds that of photoresist material by orders of magnitude. Thus, virtually no undercutting is experienced during the etching process.

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