Orthoquinone diazides, which are widely used in microlithography, have attracted considerable attention, especially in terms of their application in the production of high-contrast resists. Previous electron impact mass spectrometric results have confirmed that the primary fragmentation process of these compounds is the elimination of N, to form an indenoketene ion. This is analogous to the photodecomposition pathway which makes them effective in the lithographic process. Those results also revealed the occurrence of an alternative process, which involves a twohydrogen reduction of the intermediate species formed prior to conversion to the ketene. The present study investigates the behaviour of the orthoquinone diazides when there is an abundance of protons available to form the reduction product. Several different types of diazonaphthalenone sulfonyl esters, ranging in complexity from the monosubstituted phenol esters to disubstituted dihydroxybenzophenones, were examined using fast atom bombardment mass spectrometry. Although reduction was the primary process in the hydrogen-rich matrices, the extent of reduction was characteristic of the particular isomer as well as the matrix used.
Esters of 2‐diazonaphthalenone sulfonic acid were examined by mass spectrometry using electron impact and chemical ionization techniques. Charactristic differences in the fragmentation patterns of positional isomers have been observed. In a manner analogous to photo‐induced decompositions, the diazoketo functional groups fragment by elimination of N2 to form an indenoketene ion. An alternative process involves the apparent loss of 26 mass units from the molecular ion. The latter process is explained by evoking the abstraction of two hydrogen atoms following the loss of N2. With deuterium isotope labeling, it has been shown that the hydrogens are abstracted from the surface of the probe tip used for introduction of the samples into the mass spectrometer. It is concluded that an environment rich in hydrogen or proton‐donating properties promotes and enhances the incorporation of the hydrogen atoms and formation of the [M‐26] species at the expense of the ketene moiety, which is an important intermediate in the photoresist process. By extrapolation it may be inferred that the efficiency of the photolithographic process could be influenced by the availability of protons in the photoresist matrix.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.