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Soluble polysilanes: An interesting new class of radiation sensitive materials
Author(s) -
Miller R. D.,
Hofer D.,
Fickes G. N.,
Willson C. G.,
Marinero E.,
Trefonas P.,
West R.
Publication year - 1986
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760261610
Subject(s) - polysilane , materials science , photochemistry , radical , absorption (acoustics) , photodegradation , polymer , photocatalysis , composite material , organic chemistry , chemistry , catalysis
All high molecular weight polysilane derivatives are characterized by a very strong electronic absorption in the‐UV spectral region. The position of this absorption and the molar extinction coefficients are functions of both the nature of the substituent and the molecular weight. In this regard, both the λ max and the ϵ si‐si increase rapidly at first with increased catenation and approach limiting values al around 100 to 150 monomer units. Irradiation of these polysilane derivatives leads predominantly to chain scission and molecular weight reduction although the scission ing/crosslinking ratio is dependent on the nature of the substituents. The mechanism of the photodegradation involves both the extrusion of substituted silylene fragments and the formation of silyl radicals. Lithographically, we have exercised the polysilanes in two configurations: (1) O 2 ‐RlE etch resistant barriers in multilayer structures and, (2) thin imaginable layers for O 2 ‐RIE image transfer. In each case, the stability of the silicon polymers to O 2 ‐RIE conditions is due to the formation of a thin skin of oxide. In the case of the bilayer configurations, the images have been developed both by conventional wet development and by excimer laser ablation at either 308 or 248 nm prior to image transfer. Using either mode, we have been able to generate and transfer submicron images without difficulty. Finally, the strong optical absorption of the polysilanes, coupled with the observed bleaching upon irradiation, suggests potential as contrast enhancing materials. The contrast enhancement gained by the use of a polysilane layer has been modeled by computer simulation and demonstrated experimentally.