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Charge Transfer Azide Complexes as Negative Photoresist Sensitizers

IP.com Disclosure Number: IPCOM000076551D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Clecak, NJ: AUTHOR [+2]

Abstract

In the fabrication of microelectric devices, negative photoresists are extensively used. The negative photoresists most commonly used consist of an unsaturated linear polymer and a bifunctional cross-linking agent usually referred to as the sensitizer, dissolved in a suitable solvent. The sensitizer is a molecule which, when struck by actinic light, produces a highly reactive bifunctional molecule which cross-links the polymer, thus making it insoluble. The nonlight struck areas are then washed out, exposing the substrate in those portions and allowing the subsequent metallurgy to be performed.

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Charge Transfer Azide Complexes as Negative Photoresist Sensitizers

In the fabrication of microelectric devices, negative photoresists are extensively used. The negative photoresists most commonly used consist of an unsaturated linear polymer and a bifunctional cross-linking agent usually referred to as the sensitizer, dissolved in a suitable solvent. The sensitizer is a molecule which, when struck by actinic light, produces a highly reactive bifunctional molecule which cross-links the polymer, thus making it insoluble. The nonlight struck areas are then washed out, exposing the substrate in those portions and allowing the subsequent metallurgy to be performed.

A class of bifunctional azides consisting of a charge transfer complex between an aromatic bis azide and trinitrofluorenone has been prepared. The formation of this complex produces a new charge transfer band, not found in either of the individual components, which extends the absorption of this material far into the visible range. The obvious advantage of such charge transfer complexes is that bis azides, previously not useful because of poor absorption of actinic light, are converted into useful sensitizers which may be readily decomposed by visible light.

The following illustrates the preparation of such a charge transfer azide.

A solution of 2 g. of 3,6-diaminocarbazole in 50 ml. of water and 5 ml. of concentrated hydrochloric acid was diazotized in the normal manner at 10 degrees with 5N NaNO(2). The...