29 June 1998 Deblocking reaction of chemically amplified ArF positive resists
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Deblocking reaction mechanisms and lithographic performance in chemically amplified positive ArF resists were investigated by analyzing acid concentration and blocking level. The resists consisted of triphenylsulfonium triflate as a acid generator and either the copolymer, poly(carboxy- tetracyclododecyl methacrylate70-co- tetrahydropyranylcarboxy-tetracyclododecyl methacrylate30) or the terpolymer, poly(tricyclodecylacrylate60- co-tetrahydropyranylmethacrylate20-co-methacrylic acid20). The deblocking reaction mechanisms were evaluated from Arrhenius plots of the deblocking reaction rate constant. It was found that the deblocking reaction of both resists is ruled by two rate-determining steps, i.e., reaction-controlled in the low-temperature region and acid- diffusion-controlled in the high-temperature region. Furthermore, the copolymer resist had better post-exposure- delay (PED) stability. To clarify this result, acid loss caused by air-born contamination effect on deblocking reaction was investigated. The change of amount of blocking group by acid loss was small for the copolymer. Therefore the copolymer resist had better PED stability. Furthermore, the post-exposure bake (PEB) sensitivity of linewidth of the copolymer resist was smaller than that of the terpolymer resist. Both deblocking reaction rate constant and reverse reaction rate constant of the copolymer resist increased with PEB temperature. As a result, equilibrium constant of the copolymer was not valuable with temperature. This is the reason why the copolymer resist has low PEB sensitivity. It is concluded that small acid loss effect on deblocking reaction induces better PED stability. A resist with reverse reaction has an advantage for PEB temperature sensitivity.
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Mitsuharu Yamana, Mitsuharu Yamana, Toshiro Itani, Toshiro Itani, Hiroshi Yoshino, Hiroshi Yoshino, Shuichi Hashimoto, Shuichi Hashimoto, Hiroyoshi Tanabe, Hiroyoshi Tanabe, Kunihiko Kasama, Kunihiko Kasama, } "Deblocking reaction of chemically amplified ArF positive resists", Proc. SPIE 3333, Advances in Resist Technology and Processing XV, (29 June 1998); doi: 10.1117/12.312429; https://doi.org/10.1117/12.312429

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