27 September 2017 Supercritical CO2 drying of poly(methyl methacrylate) photoresist for deep x-ray lithography: a brief note
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Abstract
Poly(methyl methacrylate) (PMMA) is an extensively used positive photoresist for deep x-ray lithography. The post-development release of the microstructures of PMMA becomes very critical for high aspect ratio fragile and freestanding microstructures. Release of high aspect ratio comb-drive microstructure of PMMA made by one-step x-ray lithography (OXL) is studied. The effect of low-surface tension Isopropyl alcohol (IPA) over water is investigated for release of the high aspect ratio microstructures using conventional and supercritical (SC) CO2 drying. The results of conventional drying are also compared for the samples released or dried in both in-house developed and commercial SC CO2 dryer. It is found that in all cases the microstructures of PMMA are permanently deformed and damaged while using SC CO2 for drying. For free-standing high aspect ratio microstructures of PMMA made by OXL, it is advised to use low-surface tension IPA over DI water. However, this brings a limitation on the design of the microstructure.
© 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)
Rahul Shukla, Lala Abhinandan, Shivdutt Sharma, "Supercritical CO2 drying of poly(methyl methacrylate) photoresist for deep x-ray lithography: a brief note," Journal of Micro/Nanolithography, MEMS, and MOEMS 16(3), 034506 (27 September 2017). https://doi.org/10.1117/1.JMM.16.3.034506 . Submission: Received: 28 June 2017; Accepted: 6 September 2017
Received: 28 June 2017; Accepted: 6 September 2017; Published: 27 September 2017
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