Applied Science and Convergence Technology 2009; 18(2): 85-91
Published online March 1, 2009
Copyright © The Korean Vacuum Society.
Y. W. Joo , Y. H. Park , H. S. Noh , J. K. Kim , J. W. Lee
There has been a rapid progress for flexible polymer-based MEMS(Microelectromechanical Systems) technology. Polycarbonate (PC) and Poly Methyl Methacrylate (PMMA), so-called acrylic, have many advantages for optical, non-toxic and micro-device application. We studied dry etching of PC and PMMA as a function of % gas ratio in the O₂/SF?/CH₄ ternary plasma. A photoresist pattern was defined on the polymer samples with a mask using a conventional lithography. Plasma etching was done at 100 W RIE chuck power and 10 sccm total gas flow rate. The etch rates of PMMA were typically 2 times higher than those of PC in the whole experimental range. The result would be related to higher melting point of PC compared to that of PMMA. The highest etch rates of PMMA and PC were found in the O₂/SF? discharges among O₂/SF?, O₂/CH₄ and SF6/CH4 and O₂/SF?/CH₄ plasma composition (PC: ~350 ㎚/min at 5 sccm O₂/5 sccm SF?, PMMA: ~570 nm/min at 2.5 sccm O₂/7.5 sccm SF6). PC has smoother surface morphology than PMMA after etching in the O₂/SF?/CH₄ discharges. The surface roughness of PC was in the range of 1.9~3.88 ㎚. However, that of PMMA was 17.3~26.1 ㎚.
Keywords: Polycarbonate,PMMA,건식 식각,플렉시블 폴리머,반응성 이온 식각,삼성분계 가스,Dry etching,Flexible polymers,Capacitively coupled plasma