Positive resist generation

Three component, aqueous-base developable, positive-tone resists utilizing the chemical amplification principle have also recently been reported (81,82). In these systems, irradiation of a phenolic resin/inhibitor/acid generator resist generates an acid which upon mild heating, catalyzes either depolymerization or deblocking of a... 

Though certain positive resist formulations that are commercially available have been shown to function satisfactorily under MUV exposure conditions in terms of the image quality that can be generated (77,72), none of these provides a throughput capability comparable to that obtainable under NUV conditions. IBM researchers have recently described the development of a resist designed specifically for exposure in the MUV spectral region (79). The resist is a two-component, positive system based on... 

In an earlier investigation by the author [ 1 ] a sulfonium salt pair, (I), was used as a chemical amplification type resist that utilized the catalytic action of an acid generated from a sulfonium salt. In a subsequent investigation by Kamabuchi [2] an acid generator salt pair, (II), was prepared and was effective as a chemical amplification type positive resist. 

Kurihara, M. Segawa, T. Okuno, D. Hayashi, N. Sano, H. Performance of a chemically amplified positive resist for next-generation photomask fabrication. Proc. SPIE 1998, 3412, 279-291. 

Although many types of compounds have been tested as sensitizers in phenolic host resins (Novolacs, Resols, etc.) (S), all commercial positive resists employ aromatic diazoquinones of some type which photochemically generate base soluble products via Wolff rearrangement initiated by the loss of nitrogen (6). A staggering variety of diazoketones have been synthesized and evaluated for lithographic purposes, but derivatives of J[ and 2 are most commonly employed (5). 

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