Study on Synthesis and Lithographic Performance of 193nm Negative-tone Photoresist for IC Process

• Main Authors: Ko Jeng-Dar, 柯正達
• Other Authors: Hsieh Kuo-Huang
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/78124210512674811434

碩士 === 國立臺灣大學 === 化學工程學研究所 === 90 === In previous study, the researcher discovered that the acrylate resist with tert-alcohol group could process dehydrating and followed by crosslinking reaction under acid conditions. After modulating resin compositions and lithographic terms carefully, the photoresist was proved possessing the negative-tone pattern transfer characteristics. However, the acid-sensitive group of the used monomer, 3-hydroxy-3-methylbutyl methacrylate (HMBMA), its long pendent carbon-chain structure would greatly lower the glass-transition temperature (Tg) of the resultant polymer, which resulted in the finally distorted and collapsed image. Therefore, the monomer with the shorter pendent carbon-chain structure, 2-hydroxy-2- methylpropyl methacrylate (HMPMA), was synthesized in this study. By shortening the side-chain length of the resin, its Tg and thermal stability would be improved effectively, and the better lithographic performance was expected. In the research, the HMPMA monomer was also copolymerized with IBMA monomer which has high Tg value and high carbon-hydrogen ratio. Therefore, the further improvement in thermal stability and anti-etching ability of the photoresist was resulted. The results indicated that negative-tone patterns can be developed by the photoresist bearing with isopropyl alcohol. The kinetic study of the dehydration reaction showed that the dehydration rate is proportional to both concentrations of acid and hydroxy group. The experimental results demonstrated that the photoresist with high thermal stability of resin has better lithographic performance. The copolymer photoresist of the composition by (HMPMA0.5/IBMA0.5) was found to have the best lithographic performance under suitable conditions, and is a promising candidate for 193nm photoresist.