Catalytic Chain Length and Characteristic Curve in a Chemical Amplification Photoresist Using Sulfonate Photoacid Generator
Yang SK, Park CE, Ahn KD
Sulfonate광산발생제를 사용하는 화학증폭 포토레지스트의 Catalytic Chain Length 및 특성곡선
양승관, 박찬언, 안광덕
Abstract
Positive-type t-BOC phosphazene novolac alkali-soluble resist(PTPNS) is composed of three components ; novolac resin as a matrix polymer, tert-butoxycarbonyl(t-BOC) protected phophazene as a dissolution inhibitor, and pyrogallol tris(methane sulfonate) (PTMS) as a photoacid generator. In this study, the effects of dissolution inhibitor content and post exposure baking conditions have been investigated to have a better characteristic curve. Catalytic chain length and diffusion range of acid are calculated by measuring formed acid after exposure and deprotected t-BOC groups in the dissolution inhibitor. PTPNS is expected to have the best performance with 110℃ of post exposure baking temperature and 20 par of TBP content. As the catalytic chain length increases, the better sensitivity and contrast are observed. The diffusion range of photoacid is shorter than 35Å, which can not affect the resolution of sub-halfmicron lithography.
노볼락 수지를 매트릭스로 사용하고 tert-butoxycarbony1(t-BOC)기로 보호된 phosphazene(TBP)을 용해억제제로 사용하며 pyrogallol tris(methane sulfonate)(PTMS)를 광산발생제로 사용하는 새로운 삼성분계 포지티브 포토레지스트인 positive-type t-BOC phosphazene novolac alkali-so-luble resist(PTPNS)를 제조하였다. 본 실험에서는 용해억제제의 최적 함량과, 노광 후 가열온도 및 시간에 대한 최적의 공정조건을 조사하였고 노광시 생성된 산의 양과 용해억제제의 t-BOC기탈보호 정도를 측정함으로써 catalytic chain length와 산의 확산거리를 계산하였다. PTPNS는 노광후 가열온도가 110℃이고 TBF의 함량이 20phr일 때 가장 성능이 좋을 것이 예상되며 catalytic chain length가 클수록 감도와 콘트라스트가 우수하고 광산의 확산거리는 35Å 이하이므로 sub-halfmicron의 해상도(resolution)에 문제가 되지 않는다.
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