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Poly(methyl methacrylate) as masking material for microelectromechanical system (MEMS) fabrication
Author(s) -
Bodas Dhananjay S.,
Gangal S. A.
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.24091
Subject(s) - materials science , x ray photoelectron spectroscopy , silicon , contact angle , substrate (aquarium) , fourier transform infrared spectroscopy , ammonium hydroxide , chemical engineering , methyl methacrylate , etching (microfabrication) , composite material , polymer chemistry , analytical chemistry (journal) , layer (electronics) , polymer , polymerization , chemistry , organic chemistry , optoelectronics , oceanography , engineering , geology
In the present study direct current (dc) sputtered poly(methyl methacrylate) (PMMA) films deposited on silicon substrates were evaluated as masking materials for anisotropic etching of silicon in aqueous potassium hydroxide (KOH) and tetramethyl ammonium hydroxide (TMAH) solutions. Sputtered PMMA films were characterized by FTIR to ascertain the bonding, by X‐ray photoelectron spectroscopy (XPS) for the elemental composition, and by the contact angle for measuring the adhesion of the film with the substrate. FTIR and XPS data showed the presence of a poly(tetrafluoroethylene)‐like film on the silicon substrate. The interfacial tension was calculated from the contact angle value, which was 0.82 dyne/cm, confirming good adhesion of the film and the substrate. A pattern was lithographically transferred through the masking material on the silicon substrate, and the etch rate of the masking layer was calculated from the masking time data of the films. The etch rate value of 4 Å/min obtained for the masking material is low compared to the etch rate of the conventional masking materials (60 Å/min for SiO 2 and 8 Å/min for Si 3 N 4 ). © 2006 Wiley Periodicals Inc. J Appl Polym Sci 102: 2094–2098, 2006