AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP21
Plasma Etching of Pyrex Glass by Inductively Coupled Plasma for Fabrication of Microfluidic Channel

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: J.H. Park, Sungkyunkwan University, South Korea
Authors: J.H. Park, Sungkyunkwan University, South Korea
N.-E. Lee, Sungkyunkwan University, South Korea
J.S. Park, Korea Electronics Technology Institute, South Korea
H.D. Park, Korea Electronics Technology Institute, South Korea
Correspondent: Click to Email
Among many micromachining technologies of glass for microfluidic channel fabrication, DRIE (deep reactive ion etching) has been becoming increasingly attractive because of the trend towards micrometer-scale and nanometer-scale pattern in the glass or quartz. However, low etch rate of glass during plasma etch has limited the usefulness of plasma etch in the fabrication of high aspect ratio structure of glass @footnote1-3@. In this study, DRIE of pyrex glass was carried out using SF @sub 6@-based gas chemistry in a commercial 8â? inductively coupled plasma (ICP) reactor (TCP 9100, Lam Research Corp.). The glass substrate used in this experiment was pyrex glass with the thickness of 700 µm and 1cmï,´1cm squared-shape. As a etch hard-mask, Ni was electroplated into patterned SU-8 photoresist mask with the line and spacing pattern of 12-15µm on Cu /Cr /glass structure. In case of using SF @sub 6@ only, edge profiles of glass showed under-cutting below the Ni hard mask due to chemical etching and trenching or cusping at the bottom of etched channel occurred. Etch rate of @<=@0.75µm/min was obtained. On the other hand, in case of using SF @sub 6@/Ar chemistry, profile improvement without under-cutting and trenching phenomena was observed compared to the case of SF @sub 6@ chemistry but etch rate was slightly decreased. Etch rate of @<=@0.54µm/min was obtained. Ar addition was effective in the removal of etch residues by high-flux Ar ion bombardment leading to improved profile and removal of bottom trenching. XPS results indicate that sputtering etching helps remove nonvolatile by-products such as AlF@sub3@, NaF, and BF. In case of SF @sub 6@ /C @sub 4@F@sub 8@/Ar chemistry, etch characteristics of pyrex glass were similar to those of SF @sub 6@ and SF @sub 6@ /Ar chemistries but glass etch rate was slightly increased. Optimized process showed the following performance: angle profile: >88°, and glass etch rate: 0.8µm/min.