Electron irradiation of poly(olefin sulfones). Application to electron beam resists

Abstract

synopsisAll the poly(o1efin sulfones) examined degraded rapidly under electron irradiation.The dose required to effect a molecular weight distribution completely separated from the original distribution as required for fractional solution development was similar for all polymers, viz., 1-2 X 10-6 coulomb/cm2. This indicates that they all have similar values for G(scission). The film thickness of the exposed area decreased at a rate dependent on olefin structure and temperature. This process, termed vapor development, has been attributed to concurrent chain scission and depolymerization. Factors determining the rate of depropagation are discussed.

Decomposable and Template Polymers: Fundamentals and Applications

“…Poly(olefin sulfone)s constitute a broad class of polymers that, by changing the olefin structure, can have significant variation in the thermal stability of the polymer. Numerous studies have been performed to understand the effect of olefin structure on the polymerization, degradation, and vapor development of the polymer [90,[118][119][120][121][122]. Bowden and Thompson performed significant characterization on a series of olefin monomers and the application of the polymers to EUV resists [118,119,121].…”

Effect of olefin structure on the vapor‐development of poly (olefin sulfones) under electron irradiation

“…The polysulfones investigated in this paper were prepared either by UV initiation at 0°C or I y initiation with tert-butyl hydroperoxide at -80°C. Details are given elsewhere (1). Low temperature polymerization was necessary for some systems, iiotably 2-methyl pentene-l, because of ceiling temperature considerations.…”

“…They degrade under high energy irradiation with G(scission) (number of main chain hreaks per 100 eV absorbed) values significantly greater than most other degradable systems ( 3 ) . As consequence of their high G(scission), they exhibit a sensitivity greater than any other useful positive resist system currently known It has been observed previously that the film thickness of poly(o1efin sulfones) decreases with electron irradiation time at rates determined primarily by the temperature and olefin structure (1,2). Other paranreters such as molecular weight and accelerating voltage were of minor importance (5).…”

Non-chemically amplified resists for 193-nm immersion lithography: influence of absorbance on performance

“…[35][36][37][38][39] In other projects at the University of Queensland we have developed methodologies and apparatus for the free radical alternating polymerization of sulfur dioxide with olefins. Although polysulfones, such as poly-1-butene sulfone (PBS), have been shown to be sensitive to certain wavelengths of light, such as EUV, PBS lacks of etch resistance.…”