Article
  • Synthesis and Characterization of New Positive Photosensitive Polyimide Having Photocleavable 4,5-Dimethoxy-2-nitrobenzyl (DMNB) Groups
  • Choi OJ, Ryu Y, Chung MK, Lee MH
  • 감광성 DMNB 기를 함유한 새로운 포지형 감광성 폴리이미드의 합성 및 물성
  • 최옥자, 류윤미, 정민국, 이명훈
Abstract
To synthesize a new positive photosensitive polyimide precursor, parts of carboxylic acid groups in poly(amic acid) were esterified with 4,5-dimethoxy-2-nitrobenzyl bromide in the presence of K2CO3/HMPA followed by the chemical imidization of residual carboxylic acid units. The chemical structure of resulting polymer was characterized by 1H-NMR, UV/vis and FT-IR spectroscopic methods, and its thermal properties were examined by DSC and TGA. Upon UV irradiation, 4,5-dimethoxy-2-nitrobenzyl moiety underwent the photodegradation. As a result, the polymer became soluble in alkaline developer due to the formation of carboxylic acid moiety, which was used to make a micron-sized positive pattern. Sensitivity curves were obtained from the gel fraction experiments with respect to the various 4,5-dimethoxy-2-nitrobenzyl ester contents. From those curves, the sensitivity was ranged from 4000 to 6000 mJ/cm(2), and the contrast was measured to be from 3.1 to 4.9.

새로운 포지티브형 감광성 폴리이미드 전구체를 합성하기 위하여, 폴리아믹산의 일부 카르복시산 기를 K2CO3/HMPA 조건 하에서 광분해성 감광성 기인 4,5-dimethoxy-2-nitrobenzyl bromide와 반응시켜 에스테르를 형성하고 나머지 카르복시산 기를 화학적 이미드화시켜 poly[imide-co-(amic ester)]를 합성하였다. 합성된 고분자의 구조는 FT-IR, 1H-NMR 등으로 확인하였고, DSC와 TGA를 이용하여 열적 특성을 확인하였다. 또한 이 고분자에 자외선을 조사하면 감광성 기인 4,5-dimethoxy-2-nitrobenzyl 기가 분해되어 카르복시산 기를 형성함에 따라 고분자가 알칼리 현상액에 대해 용해하였으며, 이를 이용하여 포지티브 패턴을 형성할 수 있었다. 여러가지 4,5-dimethoxy-2-nitrobenzyl ester 농도를 갖는 poly[imide-co-(amic ester)]의 겔분율 실험을 통하여 감광곡선을 얻었으며, 이를 통해 이 고분자의 감광특성을 조사하였다. 그 결과 감도는 4000~6000 mJ/cm(2) 이었으며, 조도는 3.1~4.9 정도인 것으로 확인되었다.

Keywords: polyimides; photosensitive polymer; positive type; micro-lithography; poly[imide-co-(amic ester)]

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  • Polymer(Korea) 폴리머
  • Frequency : Bimonthly(odd)
    ISSN 0379-153X(Print)
    ISSN 2234-8077(Online)
    Abbr. Polym. Korea
  • 2022 Impact Factor : 0.4
  • Indexed in SCIE

This Article

  • 2002; 26(6): 701-709

    Published online Nov 25, 2002

  • Received on May 30, 2002
  • Accepted on Sep 20, 2002