HI all,

    I used AZ 4260 as the mask of DRIE to etch through Si Wafer (
500~550um). The origin recipe can reach 19 um thickness of AZ 4620
(double coating), and the ideal selectivitiy of AZ to Si is 54:1.
However, 19 um AZ 4620 seems not thick enough in entire process. Is it
because of too large expose area (Area where want to be etched in
DRIE)? My expose area is almost 50%. Or can someone suggest me to use
thicker one like AZ 9260? If so, could some experience be offered? I
pretty much appreciate it.

Alton Wang
University of Washington