面向极紫外:光刻胶的发展回顾与展望

Towards Extreme Ultraviolet Lithography:Progress and Challenges of Photoresists

半导体行业中的大规模集成电路均采用光刻技术进行加工,光刻的线宽极限和精度直接决定了集成电路的集成度、可靠性和成本。光刻技术是指利用光刻胶在紫外光或电子束下发生溶解性变化,将设计在掩膜版上的图形转移到曝光衬底上的微加工技术。随着半导体加工的光源不断进步,从g线、i线到KrF(248 nm)再到ArF(193 nm),与之匹配的光刻胶也在不断变化,以满足灵敏度、透光性以及抗刻蚀等需求。如今,极紫外(EUV)光刻已经成为公认的下一代光刻技术,然而与之对应的光刻胶还面临着不少挑战。本文简要回顾了光刻光源的发展以及对应光刻胶的变化历史,而后从极紫外光刻的原理与设备性能指标角度,结合高能光子辐射条件下的反应机理,分析了极紫外光刻胶研究中面临的灵敏度、分辨率和抗刻蚀性等方面前所未有的挑战,同时提出了对极紫外光刻胶关键性能指标与未来研究方向的展望。

Lithography enabled nanoscale fabrication in the semiconductor industry;Its resolution and accuracy directly determined the integration,reliability,and cost of integrated circuits.Lithography is a micro-processing technology that uses the solubility switch of photoresists upon the exposure of ultraviolet light or electron beam,to transfer the pre-designed patterns on the mask to the substrate.With the continuous advancement of light sources used in semiconductor processing,from g-line and i-line to KrF(248 nm)and then to ArF(193 nm),the photoresist is also constantly developing to meet requirements of sensitivity,transmittance,and resistance to etching.Nowadays,extreme ultraviolet(EUV)lithography has been recognized as the next generation of photo-lithography technology;however,the corresponding photoresist is still facing substantial challenges.This article will briefly review the development of lithography light sources and the historical changes in corresponding photoresists;and then discuss the challenges,such as sensitivity,resolution,and etching resistance for EUV photoresists.Based on this,the future development direction of EUV photoresists is proposed.