Profile control of a borosilicate-glass groove formed by deep reactive ion etching

Abstract

Deep reactive ion etching (DRIE) of borosilicate glass and profile control of an etched groove are reported. DRIE was carried out using an anodically bonded silicon wafer as an etching mask. We controlled the groove profile, namely improving its sidewall angle, by removing excessively thick polymer film produced by carbonfluoride etching gases during DRIE. Two fabrication processes were experimentally compared for effective removal of the film: DRIE with the addition of argon to the etching gases and a novel combined process in which DRIE and subsequent ultrasonic cleaning in DI water were alternately carried out. Both processes improved the sidewall angle, and it reached 85 o independent of the mask-opening width. The results showed the processes can remove excessive polymer film on sidewalls. Accordingly, the processes are an effective way to control the groove profile of borosilicate glass.

Study of High Aspect Ratio NLD Plasma Etching and Postprocessing of Fused Silica and Borosilicate Glass

“…In [18], it was shown that SiO 2 etching was increased by adding Ar for up to a certain value. However, including Ar to the gas chemistry may increase the physical etching due to ion bombardment and may contribute to increase in the sidewall angle [13]. In our experiment with the NLD plasma, we found that 10 to 50 sccm of Ar helped in reducing contamination on the etched surface because of the ion bombardment.…”