SiO2 film with a thickness of 2 micro is RIE etched, the etch parameters are as
follows,
CHF3:30sccm
Pressure:6Pa
RF Power:300W
Etch mask:P.R.
the etch result shows that the etching rate biases at different etch window
size.
In order to improve the uniformity, the pressure is decreased to 2.6Pa and the
flow rate of CHF3 is increased to 40sccm, and the etch was tried again. The etch
result shows better uniformity but with another problem. Something remained at
the
bottom of the etch window, especially where near to the side wall of etch
window.
Would any body give me an explanation of this kind of phenomenon and provide
some
better advice to improve the etch uniformity of RIE? thanks