The Improvement of the Pattern Wiggling Profile by Photo Resist Treatment

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For advanced node such as 14nm technology and beyond, Patterning is one of the key challenges in the semiconductor industry. Advanced pattern transfer techniques such as negative tone development (NTD) technology are under investigation to enable the aggressive pitch requirements demanded. Even though, just as traditional positive tone development (PTD) technique, a pattern wiggling issue has arisen with the reduction of pattern dimension during dry etch process, which prevents the successful pattern transfer. Two kinds of wiggling solutions have been proposed. One is the lithographic solution. The other is the gases treatment in the tri-layer process. However, with the decrease of device size, a single method hardly eliminates wiggling and meets the pattern target. Besides, the requirements for Line Edge Roughness (LER)/Line Width Roughness (LWR); critical dimension uniformity (CDU); through pitch are extremely aggressive in advanced technology. Therefore, the characteristics of the dry etching process play an increasingly import role in defining the outcome of the pattern process. In this paper, we demonstrate the method of PR treatment (NTD techniques) that improves LER/LWR for trench pattern in dry etch CCP etcher. Meanwhile, the difference of PR treatment methods between traditional and special treatment is illuminated. What’s more, in PR treatment methods, other pattern behavers such as CD, through pitch are concerned during improving LER/LWR process, and aim to get a good result of all aspects. At last, the role of various plasma etch parameters that influence the key patterning metrics of CD, resist selectivity and LER/LWR are studied.