Mass spectrometric studies of sulfonyl esters of diazonaphthalenones: Relationship between fragmentation patterns and photolithographic mechanisms

Abstract

AbstractEsters 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.