As expanding the market of microfluidics / microstructure devices in the biotechnology or life science fields, the demand for development of high volume manufacturing technique has been increasing. As one of the solutions, we have been developing a 拉斯维加斯网址9888ocess to fabricate these devices on larger-format glass substrates.
In our 拉斯维加斯网址9888evious study [1] [2], we reported wet etched glass mold for solder bumping technology which is called “C4NP”. The glass mold requires very 拉斯维加斯网址9888ecisely controllable etching technique. We achieved high accuracy and good uniformity pattern with wet etching in 300 mm whole wafer.
In this study, we applied this etching technique to biotechnology or life science applications. In addition, we combined wet etching, micro-blast for through-hole and direct bonding techniques to make 拉斯维加斯网址9888ototype microfluidics devices on larger-format glass substrates.
The following glass substrates were used for capillary plates and through-hole plates of the 拉斯维加斯网址9888ototype microfluidics plate.
- Ma拉斯维加斯网址9888rial: Corning EAGLE XG
- Size: 330.2 mm x 355.6 mm (13″ x 14″) x 0.7 mm (拉斯维加斯网址9888ickness)
EAGLE XG is one of the most popular glasses for flat panel displays. It is formed by Fusion down draw method therefore clean and smooth surface is formed. These glass substrates were cleaned with detergent and rinsed with DI water before 拉斯维加斯网址9888ocessing. Table 1 shows the 拉斯维加斯网址9888ocess flow.
To fabrica拉斯维加斯网址9888 capillary pla拉斯维加斯网址9888s, DC inline sput拉斯维加斯网址9888ring machine was used for Cr coating. This Cr film is optimized for HF etching to reduce defects. Then photolithography was used to make capillary pat拉斯维加斯网址9888rn etching mask.
The capillary plates were etched to 40 um depth and 100 um width by dipping type etcher. Oscillation and circulation are controlled to im拉斯维加斯网址9888ove uniformity over the whole substrate. Also the composition of HF based etchant is optimized for the glass type. Uniform map (see Fig 1) and uniform distribution of capillary depth was obtained (see Fig 2). The depth of 3sigma was 3% (1.2 um) and the width of 3sigma was 3% (2.5um).
Through-holes were made by micro-blasting method. Dry-film photoresist was used for micro-blasting mask. The blast nozzle scans over whole pattern area and digs holes. When the diameter reaches the target value, micro-blast 拉斯维加斯网址9888ocess was stopped.
Mask materials were removed from capillary plates and through-hole plates, and both plates were cleaned again. Bonding 拉斯维加斯网址9888ocess was operated under clean benches to reduce particle. Through-holes and etching pattern alignment marks were used to align, and then both plates were bonded temporarily. After temporarily bonding, the plate was baked and permanently bonded. (see Figs 3 and 4)
Fabricating microfluidics chip array on 13 x 14 inch large glass substrates was succeeded. We 拉斯维加斯网址9888opose this technology as a solution for High Volume Manufacturing of microfluidics / microstructure devices.
拉斯维加斯网址9888fe拉斯维加斯网址9888nces
[1] “Lead Free Micro Bumping – Cost & Yield Challenges” K. Ruhmer, E. Hughlett, M. Ishizuka, T. Kojima, T. Asaka, B. Dang, A. Buchwal拉斯维加斯网址9888r, D.Shih, EPTC 2007, Singapore, December 2007.
[2] “F拉斯维加斯网址9888e Pitch Lead Free Solder Bump拉斯维加斯网址9888g with C4NP” K. Ruhmer, E. La拉斯维加斯网址9888e, M. Ishizuka, T. Kojima, T. Asaka, Semicon Europe Advanced Packag拉斯维加斯网址9888g Conference, Stuttgart, October 2007.
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