Dear all,

I just want to know if there is anybody who has a similar problem.
When I etch 2300 nm of thermal SiO2 in our AMS200 ICP Dielectric Etcher
(with use of C4F8 and H2) I got problems with small particles 1 micron
big for example which fall down during process an passivates my etching
structures.
I think this particles are coming from the aluminium clamp ring shield.
After each wafer we make a O2 Cleaning because we are etching with
C4F8. Cleaning is as long as one wafer will be etched (approximately
7,5 minutes).

My process is like this:

C4F8:   13 sccm
H2:     40 sccm
pressure: 2,8 E-3 mbar
Source: 2800 Watt
Substrate Holder: 250 Watt
Temperature: 0°C

Is there maybe a possibility for another process with good etch rate and
good selectivity to PR?
On our ICP we have this gases available:

CF4, CHF3, H2, C4F8, O2

I use PR-Mask (1,7 microns thick) to etch 2200 nm thermal oxide.

Thanks for each answer.

Regards,

Carsten

LITEF GmbH, Germany