Hi,every one:

Is any one know a good RIE Recipe for 1um SiON(index 1.75) etching?
I need to etch 1um SiON(index 1.75). The mask layer will be Si or
ZEP520(e-beam resist). It seems zep520 is not capable to etch 1um of
SiON. So I have used 200nm polySi on the top of SiON as a mask. I had
used CHF3 to etch SiON, but the result is not so good. I have 120nm
holes from design, but after etching, they became almost 250nm. How can
I reduce the horizontal etching on Si?

Any suggestion will be appreciated!