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Fabricating Thin Film, Metal Crossover

IP.com Disclosure Number: IPCOM000094312D
Original Publication Date: 1966-Sep-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Esch, RP: AUTHOR [+2]

Abstract

This method is for fabricating thin film, metal crossover networks having a thin polymer insulating layer separating the respective conductive patterns.

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Fabricating Thin Film, Metal Crossover

This method is for fabricating thin film, metal crossover networks having a thin polymer insulating layer separating the respective conductive patterns.

The polymer layer is formed by applying a solution of polyvinyl formamide and a solvent. Polyvinylformamide is manufactured by the simultaneous hydrolysis and acetylization of polyvinyl acetate. The method relies on two properties of polyvinylformamide. The first is its ease of removal by various solvents such as trichloroethylene, ethylene dichloride, etc., where the polyvinylformamide layer has not been subjected to temperatures higher than approximately 150 degrees C. The second is the insensitiveness of the layer to the same solvents after being cured at temperatures between 185 degrees C to 400 degrees C.

Polyvinylformamide layer 14 of the proper thickness is placed over metal conductor pattern 12 on wafer 10, as in A, and air-dried at approximately 130 degrees C. Photoresist coating 16 is applied over layer 14 which is exposed to a desired pattern. The pattern is developed, as in 13, after prebaking the photoresist at a suitable temperature less than 130 degrees C.

The resultant wafer is then dipped in one of the mentioned solvents and subjected to ultrasonics to remove portions of layer 14 to produce the desired pattern, as in C. The pattern is easily formed in coating 14 because it has not been exposed to temperatures exceeding 150 degrees C. The photoresist is remov...