Deep dry etching of fused silica using C4F8/Ar inductively coupled plasmas

• Published in: Journal of materials science. Materials in electronics Vol. 28; no. 1; pp. 480 - 486
• Main Authors: Lin, Laicun, Jing, Xiangmeng, Liu, Fengman, Yin, Wen, Yu, Daquan, Cao, Liqiang
• Format: Journal Article
• Language: English
• Published: New York Springer US 2017
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Optical and Electronic Materials; Substrate Temperature; Etch Rate; Fuse Silica; Bias Power; Chamber Pressure
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-016-5546-6

This paper reports the etching process of fused silica by inductively coupled plasmas (ICP) for through glass via (TGV) applications. Mixed C 4 F 8 and Ar were used as etching gases in present experiments. The effects of key factors, including etching gases, chamber pressure and substrate temperatures, on etch rate and via profile were studied. Results showed that a high etch rate of about 0.75 μm/min with smooth and vertical sidewall of TGVs can be obtained. Compared to Ar flux and chamber pressure, the effect of C 4 F 8 flux on etch rate is more remarkable. Vertical vias (>89°) can be achieved by increasing the substrate temperature and decreasing the mixing ratio of C 4 F 8 and Ar. Besides, micro-pillars at the bottom of via were observed when the substrate temperature was set at 0 °C. As the substrate temperature reached to 80 °C, micro-pillars were removed clearly. Optimized results indicate that the ICP etching is an effective method for fabricating TGV.