  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 85o 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.
