Specific Process Knowledge/Etch/ICP Metal Etcher/silicon oxide

Slow etch of SiO2 with resist as masking material - with direct clamping

This recipe can be used for slow etching of SiO2 with resist as masking material when normal clamping is possible. Normal clamping is prefered because it give the best and most repeatable cooling of the wafer. Here are some test results presented.

Parameter	Resist mask
Coil Power [W]	200
Platen Power [W]	25
Platen temperature [oC]	0
CF4 flow [sccm]	20
H2 flow [sccm]	10
Pressure [mTorr]	3

Results	Test on maskless wafer
Etch rate of thermal oxide	44.1 nm/min (50% etch load) (01-02-2014)
Selectivity to resist [:1]	~0.9
Wafer uniformity (100mm)	±1.6% (01-02-2014)
Profile [o]	Take a look at the images but be aware that the resist profile was not good to begin with.
Images (click on the image to view a larger image)	Contour plot of the etch rate over the wafer, 9 points measured
SEM profile images	Some chemicals of the MVD and the surface reaction Resist profile before etch Resist profiler after etch 01-02-2014. Resist profiler after etch 01-02-2014. No line width reduction observed.