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Negative Resists From Positive Resists

IP.com Disclosure Number: IPCOM000089786D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ouano, AC: AUTHOR [+2]

Abstract

It has been established that exposure (ultraviolet (UV) light) of a mixture of diazo-oxide-type photoactive compounds and resins in vacuum leads to formation of the phenyl ester of the resin. When the photoactive compound contains two or more diazo-oxide groups, the resultant phenyl ester cross-links the resin and produces a material which dissolves slowly in a base developer relative to a resist exposed to UV light in air.

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Negative Resists From Positive Resists

It has been established that exposure (ultraviolet (UV) light) of a mixture of diazo-oxide-type photoactive compounds and resins in vacuum leads to formation of the phenyl ester of the resin.

When the photoactive compound contains two or more diazo-oxide groups, the resultant phenyl ester cross-links the resin and produces a material which dissolves slowly in a base developer relative to a resist exposed to UV light in air.

A silicon wafer was coated with a diazo-phenolic resin photoresist and exposed through a mask to UV light emitted from a high pressure mercury in vacuum. Subsequently, the mask was removed, and the wafer flood reexposed to the same UV lamp but in the presence of air.

The exposed resist was then developed in a basic, aqueous developer. The image developed by this process is an image which is normally associated with a negative acting resist. Thus, a resist which is normally a positive resist can be used as a negative resist by UV exposure in vacuum through a mask followed by UV flood exposure in air, and developed in a very dilute developer system, i.e., a sodium-silicate-based developer.

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