Study on the Key Parameters in Etching of Fused Silica Using Atmospheric Inductively Coupled Plasma

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Atmospheric Pressure Plasma Processing (APPP) of silicon-based optics and wafers is a form of chemical etching technology developed in recent years. The material removal rate is comparable to those of conventional mechanical processing methods in precision fabrication. Moreover, there is no mechanical contact or physical loading on the substrate surface, hence no surface or sub-surface damages are induced. Inductively coupled plasma is one realization of APPP. In this work, inductively coupled plasma torch is used to generate plasma and excite etchant particles at atmospheric pressure. These active particles then diffused to the workpiece surface, react with its atoms to form volatile products. The activity and number of particles in plasma are influenced by processing parameters such as input power, distance between nozzle and substrate surface, flow rate of plasma gas argon and precursor gas CF4. These factors have various impacts on material removal rate. Processing experiments are conducted on fused silica to investigate the parameters’ influences on material removal rate. The basic interaction between substrate surface and plasma is illustrated, then the relationships between processing parameters and material removal rate are analyzed. From the experiments some trends are derived. Material removal rate rises with the increase of power and flow rate of CF4, whereas decreases with the increase of processing distance, etc. The etching footprint is proved to be near Gaussian-shaped and believed to have high potential for deterministic surface processing.

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469-474

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August 2014

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© 2015 Trans Tech Publications Ltd. All Rights Reserved

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[1] D.M. Aikens, H.D. Bissinger, Overview of small optics for the National Ignition Facility, Proc SPIE 3782(1999) 476-87.

Google Scholar

[2] J.H. Campbell, R.A. Hawley-Fedder, C.J. Stolz, J.A. Menapace, M.R. Borden, P.K. Whitman, et al., NIF optical materials and fabrication technologies: an overview, Proc SPIE 5341(2004) 84-101.

DOI: 10.1117/12.538471

Google Scholar

[3] A.E. Hatheway, S.J. Hoskins, Aspheric surface figuring of fused silica using plasma-assisted chemical etching, Proc SPIE 2542(1995) 220-230.

DOI: 10.1117/12.218668

Google Scholar

[4] B. Wang, J. Zhang, S. Dong, New development of atmospheric pressure plasma polishing, Chinese Optics Letters, 7(2009) 537-538.

Google Scholar

[5] H.P. Stahl, A. Schindler, G. Boehm, T. Haensel, W. Frank, A Nickel, et al., Precision optical asphere fabrication by plasma jet chemical etching (PJCE) and ion beam figuring Proc SPIE 4451(2001) 242-248.

DOI: 10.1117/12.453622

Google Scholar

[6] E-B. Kley, A. Schindler, T. Haensel, D. Flamm, W. Frank, G. Boehm, et al., Ion beam and plasma jet etching for optical component fabrication, Proc SPIE 4440(2001) 217-227.

DOI: 10.1117/12.448043

Google Scholar

[7] E. Atad-Ettedgui, P.K. Subrahmanyan, G. Gardopée, D. Lemke, Reactive atom plasma (RAP) processing of mirrors for astronomy, Proc SPIE, 7018(2008) 701809-12.

DOI: 10.1117/12.786991

Google Scholar

[8] M. Castelli, R. Jourdain, G. McMeeking, P. Morantz, P. Shore, D. Proscia, et al., Initial Strategies for 3D RAP Processing of Optical Surfaces Based on a Temperature Adaptation Approach, Proceedings of the 36th International MATADOR Conference, (2010).

DOI: 10.1007/978-1-84996-432-6_124

Google Scholar

[9] H. Takino, N. Shibata, H. Itoh, T. Kobayashi, K. Yamamura, Y. Sano, et al., Fabrication of optics by use of plasma chemical vaporization machining with a pipe electrode, Applied Optics, 41(2002) 3971.

DOI: 10.1364/ao.41.003971

Google Scholar

[10] M. Castelli, R. Jourdain, P. Morantz, P. Shore, Reactive Atom Plasma for Rapid Figure Correction of Optical Surfaces, Key Engineering Materials, 496(2011) 182-187.

DOI: 10.4028/www.scientific.net/kem.496.182

Google Scholar

[11] G.S. Selwyn, H.W. Herrmann, J. Park, I. Henins, Materials Processing Using an Atmospheric Pressure, RF-Generated Plasma Source, Contributions to Plasma Physics, 41(2001) 610-619.

DOI: 10.1002/1521-3986(200111)41:6<610::aid-ctpp610>3.0.co;2-l

Google Scholar

[12] W.J. O'Brien, Characterisation and Material Removal Properties of the RAP™ Process, PhD thesis, Cranfield University, (2011).

Google Scholar