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Masking Process for Semiconductor Fabrication

IP.com Disclosure Number: IPCOM000092771D
Original Publication Date: 1967-Jan-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Esch, RP: AUTHOR [+3]

Abstract

In this process, a film is provided between the semiconductor substrate and a photolithographic masking layer used to define the areas to be etched. The process is useful for etching apertures in insulating coatings such as thermally grown or sputtered silicon dioxide films.

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Masking Process for Semiconductor Fabrication

In this process, a film is provided between the semiconductor substrate and a photolithographic masking layer used to define the areas to be etched. The process is useful for etching apertures in insulating coatings such as thermally grown or sputtered silicon dioxide films.

A solution of polyvinylformamide in a suitable solvent, such as dichloroethane, ethylene dichloride, thrichloroethylene, etc., is prepared and spun on the surface of the substrate over the insulating layer to be etched. The resultant film is dried at a temperature of approximately 130 Degrees C. A photolithographic etchant masking layer is then applied, dried, exposed, and developed. The polyvinylformamide layer is dissolved from the holes in the photolithographic layer with a suitable solvent such as a solution of 40% dichloroethane and 60% isopropyl alcohol. For best results, the solution is varied depending on the particular drying temperature and time. The exposed insulating layer is then etched in the conventional manner. The composite photolithographic coating and polyvinyl film are removed by ultrasoning on a suitable solvent such as dichloroethane.

The use of the polyvinylformamide film beneath the photolithographic masking layer improves adhesion to surfaces to be etched without lengthy bakings at temperatures above 130 Degrees C. Such arrangement facilitates the removal of the masking layer by eliminating the necessity for mechanical abr...