Photoresist polymers electron beam

PET reactions of benzylic silanes with polycyano-aromatic compounds have been applied to photoresist and electron-beam resist technologies. "" The photoreaction of poly(4-trimethylsilyl-methylstyrene) in benzene-acetonitrile with DCB affords insoluble polymer via photo-cross-linking, which contains 4-cyanophenyl-methyl groups. In the case of 1,2,4,5-tetracyanobenzene, soluble 2,4,5-tricyanophenylmethyl-substituted polystyrene is produced. But,... 

Photoresists and electron-beam resists are the key to the success of VLSI electronic circuits. Without these resists, most electronic equipment would not exist. These polymers are spun onto the semiconductor and exposed to the circuit pattern leading to main chain scission or crosslinking. Subsequently, unpolymerised sections are removed. This process is employed either in wet or in dry conditions. This is known as the photolithographic process, which is part of the semiconductor fabrication technology. Further treatment includes diffusion of various semiconductor elements and metallisation for conduction lines. Layer by layer, the total package is developed. Current research is now directed toward finer features in the patterns and changes in the surface characteristics for subsequent layers. 

If one wishes to prepare a positive photoresist it is important to obtain polymers vdiich undergo efficient chain scission in the solid phase. Recently we reported studies on a series of copolymers of styrene with a variety of ketone functional groups which were introduced by copolymerization with substituted vinyl ketone monomers. The copolymer structures are shown schematically in Table V. Two processes are responsible for the reduction in molecular weight in these polymers when irradiated with either UV light or electron beams. These are shown schematically below. 

This Report follows the format of the previous one except that, commencing this year, the patents section will be omitted. Academic and industrial research in this field continues to be prolific, particularly in areas of photopolymerization such as electron beam curing and photoresists. Other areas, such as the photosensitized degradation of polymers for producing photodegradable plastics, have diminished to only a few articles, and consequently these will now be included in the section dealing with photo-oxidation and photodegradation. 

Photosensitized degradation of poly(olefin sulfones) similar to the Hg(3P) photosensitized reactions of olefin sulfones make them subject to photodegradation in easily accessible wavelength regions. Almost all poly(olefin sulfones) have been reported only as positive tone electron beam resists (4). As the only exception, poly(5-hexene-2-one sulfone) has been reported as a positive tone photoresist with or without a photosensitizer, benzophenone (5). Because this polymer has a carbonyl chromophore, its photosensitivity is clearly derived from the polymer structure itself. 

H. Meier and K. Zeller, The Wolff rearrangement of diazo carbonyl compounds, Angew. Chem. Int. Ed. (English) 14, 32 (1975) M. Kaplan, D. Meyerhofer, Response of diazoquinone resists to optical and electron beam exposure, RCA Rev. 40, 169 (1979) Sensitivity of diazoquinone resists to optical and electron beam exposure, Polym. Eng. Sci. 20, 1073 (1980), D. Ilten, R. Sutton, Spectrophotometric determination of photoresist photosensitivity, J. Electrochem. Soc. 119, 539 (1972) B. Broyde, Exposure of photoresists, J. Electrochem. Soc. 117, 1555 (1970). R. Dammel, Diazonaphthoquinone based Resists, p. 15, SPIE Press, Bellingham, WA (1993). " ibid., p. 17. 

The production of modem printing plates involves photopolymerization or photo-crossiinking of light sensitive polymers called photoresists to solubilize or insolubize the exposed area, depending on the kinds of resists used, followed by development and etching. The fast drying of wet ink films can be accomplished by exposure to u.v. or electron beams which photochemically initiated rapid photopolymerization of the wet ink to solid patterns... 

The sensitivity of PE to cross-linking by radiation is the basis of commercial processes for producing cross-linked polymers by, eg, electron-beam irradiation. Conversely the easy scission of polysulfones, with elimination of SO2, is the basis of some photoresists. 

Bignozzi, M. C., et al. (1999). Lithographic results of electron beam photoresists prepared by living free radical polymerization. Polym. Bull., 45(1) 93-100. 

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