Influence of Loading Position and Reaction Gas on Etching Characteristics of PMMA in a Remote Plasma System

Transcription

1 Korean Chem. Eng. Res., Vol. 44, No. 5, October, 2006, pp Remote r i l m zi PMMAm Š z Çmk o o }e q (2006 1o 5p r, o 16p }ˆ) Influence of Loading Position and Reaction Gas on Etching Characteristics of PMMA in a Remote Plasma System Cheonkwang Ko and Wongyu Lee Department of Chemical Engineering, Kangwon National University, 192-1, Hyoja 2-dong, Chunchon, Kangwon , Korea (ReceivedG5 January 2006; accepted 16 June 2006) k h o ql e e rp remote v pn l o l PMMAp e rl l v, p d, v o p l e p r m. v op lv v l p p PMMA e m. v l l p PMMA r, v p v PMMA p v e rp v m. e ~l p kp v l e v m l e p v p k pl. Abstract Etching process of PMMA (Polymethyl Methacrylate) on glass surface was investigated by dry etching technique using remote plasma. To determine the etching characteristics, the remote plasma etching was conducted for various process parameters such as plasma power, reaction gas and distance from plasma generation. As the distance from the plasma generation was increased, the etch rate of PMMA was linearly decreased by radical density in plasma. PMMA has removed by reactive radicals in the plasma. The etch rate increased with plasma power because of more reactive radicals. The etch rate and surface roughness of PMMA increased with O 2 concentration in the etchant. Key words: Remote Plasma, PMMA, Etch Rate, Loading Position 1. ~ pdp v l vd p p ot Ž p n p. pdp m l r t p tn [1]. Ž p ee r l e, e p e ˆ p lk [2, 3]. p e pl RIE(reactive ion etching), ECR(electron cyclotron resonance), ICP(inductively coupled plasma) p l v e q pn l v p. RIEp n p r k l v e p, p p p e l p p rp p. ECRp n v l qqp rp Žl p lv rp p. ICPp n p RF r p v To whom correspondence should be addressed. wglee@kangwon.ac.kr rl, r p pm l v rl l e p f p eˆ p [4-6]. v e, ˆ p p p p ~p s, p ˆ, rs p l p m p p pp e rp r rl pp n l. l l LIGA(lithographie galvanoformung abformung) rl v f n PMMA(polymethyl methacrylate)p e l kk k., v m o l remote v pn l d ol PMMA p e p v op p l m. v l p e PMMAp l tl PMMAp r p f r m p m. e l sq PMMAp, r p o, v m p s l o p r p FTIR(fourier-transformation infrared) AFM(atomic force microscope) p r l p m. 483

2 484 } Ëpo 2. Remote v e rl n q p Fig. 1l ˆ l MHzp tž v remote v 5.9 cm quartz l pp k v mlp sr m. e l n Žp 1.5 cm 1.5 cm p slide glass n mp, q p 100,000p PMMAm p 1:10p p l n m. l n PMMA 1,500 rpmp d Ž l 3µm e. dl Ž PMMA Ž 80 Cl s rp o ~p, dee r p v kk. v l n p dm v l p PMMAp e m. v o p l PMMAp e p kk o v p p e p o Fig. 2} o m. m 25 C o r mp, r~rp e s p Table 1l ˆ. v o p l PMMA e m m. e kk o Alpha-step(Alphastep IQ, KLA Tencor)p n l PMMA e r p r mp, e l q PMMAp r l FTIR(EXCALIBER Series, BIO-RAID)p n m. Remote v l p e r p o AFM(Nano Scope Multimode, Digital Instrument)p n m. 3. y v e r l remote v rnp r PMMA r m. pe l p tl e (etching rate: Å/min) m, r l e m. e l m p r v, v p ~, v o p m e p r m r e Fig. 3l ˆ l. Fig. 3(a) v p 200 W r ˆl pe p 10 p l v p ~m v o p l e r m, Fig. 3(b) v ol v p ~ l e r m. PMMA Ž Žp v op o l v e rp p ˆ. v l p v op l l e p. Fig. 3(b) v v l PMMA e p, v p v v p pm r p v rm p p p PMMAm p l r pp v p p. Fig. 3l p ~, air, v, v m Fig. 1. Schematic diagram of the remote plasma etching system. Fig. 2. Sample positions in the plasma cleaning chamber ( : plasma generated center). Table 1. Parameters of plasma cleaning condition Parameter Variable condition RF power(w) 100, 150, 200 W Exposed Time(min) 10 min Gas flow rate(sccm) 30 sccm Pressure(mtorr) 300 mtorr Temperature( o C) 25 o C Reactant gas O 2, Air, N 2, N 2 +H 2 (97:3) o44 o k Fig. 3. Etching rate with respect to plasma parameters: (a) loading position and reactant gas at 200W, (b) plasma power and reactant gas at plasma generated center.

3 Remote v l PMMAp e 485 Fig. 4. FTIR spectra as a function of RF power and loading position during remote O 2 plasma etching: (a) site, (b) site, (c) site, (d) site. dl PMMA r pp ˆ l. PMMA r re p ~ t p l e l m p p. v l qp l p p PMMAm p p p p v l p p. v ol 200 Wp v p 2430 Å/minp e p. PMMA 3µm d Ž d p m air v 30 sccmp o p op l 10 e rp m. Air v m p o 80:20p l 30 sccmp o p p. Fig. 4 v l p PMMA Ž e p o m v l p pp pl FTIR r p. Fig. 5 air v p pp pl FTIR r p. Žql p oq p 2,979 cm -1 : C-CH 3, 2,948 cm -1 : -CH 2 -, 2,840 cm -1 : C-H stretch vibration groups -CH 3 and -CH 2 - p, d p e d l q p PMMAp ˆ p [7]. v l p PMMA e k H 2 O, CH 4, CO, CO 2 p pp, O *m PMMAmp t pl p l l p r [8]. e p o v op lv e l sq PMMA v p. p v v e rl p tl PMMAp qpp p. PMMAp e rl n e p o v op v v l p pm. v p v o e rp 2,800~3,000 cm mll 1 p d Žl kp PMMA p p p. Fig. 6p v v l p 10 PMMA e FTIR r p. p e l k p p v v l p r PMMA qp, FTIRl p l lpp p p. Fig. 7p v m d 29 sccm 1 sccmp o p ope 10 v v o p l e FTIR r p. v m v l p e l PMMA r ~ n pmp rq p rp p p p p v l p. r l n ~p v rp p p p pq (pm, rq, )p, p pq p p e r pp pp p ~ l ˆ p f e ˆ. v l p p v oq r qp v p l v l v pn o p pp d l p rp pl p l p lv [9]. Korean Chem. Eng. Res., Vol. 44, No. 5, October, 2006

4 486 } Ëpo Fig. 5. FTIR spectra as a function of RF power and loading position during remote air plasma etching: (a) site, (b) site, (c) site, (d) site. Fig. 6. FTIR spectra as a function of RF power and loading position during remote N 2 plasma etching: (a) site, (b) site, (c) site, (d) site. o44 o k

5 Remote v l PMMAp e 487 Fig. 7. FTIR spectra as a function of RF power and loading position during remote N 2 +H 2 (97:3) plasma etching: (a) site, (b) site, (c) site, (d) site. Fig. 8. AFM images of the surface exposed to remote plasma etching at the various reactant gas at sites: G(a) O 2, (b) Air, (c) N 2. Fig. 8p remote v e rl p PMMA l l m p t kk o p ~ l ˆ p. v } l PMMA 1.55 Åm. e p o v o, mp rs p 10 v } PMMAp Å p ˆ (Fig. 8(a)). Airm v v } PMMAp Å, 2.57 Åp v p ~ p o p } PMMA p ˆ p (Fig. 8(b), (c)). v l pm l p v r le v. 4. e l o ql e e rp v pn l o l Ž PMMAp e l l s m. v op l PMMA e l kk k. v op lv Korean Chem. Eng. Res., Vol. 44, No. 5, October, 2006

6 488 } Ëpo v l p p PMMA e m. v p ~ p l PMMA r l pl m p t p ~ t p o p v e v p ˆ l. v p v PMMAp FTIR p, v op e p o lv p v m. v l pq (pm, rq, )l p PMMA r, v v o p PMMAp pl m p t ppp k pl. v r PMMA o p v pm l p le p v p k pl. y 1. International Technology Roadmap for Semiconductors, ITRS, (2002). 2. Louis, D., Nier, M. E., Fery, C., Heitzmann, M., Papon, A. M. and Renard, S., Poly-Si Gate Patterning Issues for Ultimate MOSFET, Microelectron. Eng., 61-62, (2002). 3. Bell, F. H., Jouber, O. and Vallier, L., Influence of the Nature of the Mask on Polysilicon Gate Patterning in High Density Plasma, Microelectron. Eng., 30, (1996). 4. Jung, J. K. and Lee, W. J., Dry Etching Characteristics of Pb (Zr,Ti)O 3 Films in CF 4 and C1 2 /CF 4 Inductively Coupled Plasmas, Jan. J. Appl. Phys., 40(3), (2001). 5. Basit, N. A. and Kim, H. K., Crystallixation of Pb(Zr,Ti)O 3 Films Prepared by Radio Frequency Magnetron Sputtering With a Stoichiometric Oxide Target, J. Vac. Sci. Technol. A., 13(4), (1995). 6. Lin, Y. Y., Liu, Q., Tang, T. A. and Yao, X., XPS Analysis of Pb (Zr 0.52 Ti 0.48 )O 3 in Film After dry-etching by CHF 3 Plasma, Applied Surface Science, 165(1), 34-37(2000). 7. Sugimoto, F. and Okamura, S., Adsorption Behavior of Organic Contaminants on a Silicon Wafer Surface, J. Electrochem. Soc., 146(7), (1999). 8. Pang, S. W., Sung, K. T. and Ko, K. K., Etching of Photoresist Using Oxygen Plasma Generated by a Multipolar Electron Cyclotron Resonance Source, J. Vac. Sci. Technol. B., 10(3), (1992). 9. Delfino, M., Salimian, S., Hdul, D., Ellingboe, A. and Tsai, W., Plasma Cleaned Si Analyzed in situ by x-ray Photoelectron Spectroscopy, Secondary Ion Mass Spectrometry, and Actinometry, J. Appl. Phys., 71(2), (1992). o44 o k