Shutdown drytek2 2003-01-13 16:00:22: Finished initial test of modified Drytek2

mcvittie at mcvittie at
Wed Jan 15 10:06:37 PST 2003

Drytek2 is open for general use although we will doing more 
characterization of the different std processes in the weeks to
come.  We will try to do this work during early mornings when there
light load in the lab.
Here is what is new on Drytek2:
1. New electrodes with larger water lines.
2. Repair of vacuum (water) leaks. Now has leak rate < 1mT/min
3. Clean up of front load door
4. Rebalancing of power to electrodes. Std poly etch now has
electrode to electrode uniformity < +/- 5%.
5. Better across electrode uniformity for std poly etch proc < +/-5%
Other Issues:
1. Electrode to electrode uniformity does change with process
conditions, so do not expect 5% uniformity on all processes. We have a 
multi-electrode readout box that I am going leave available by the side of  
tool. It gives a rough indication of how the power to the different electrodes changes
as you change from the std poly etch process.
2. The new electrodes are thicker. This results in a reduction
in the gap between the electrodes and an increase in plasma
density for a constant rf power. Thus, you should expect to see 
an increase in etch rate if you run the old process conditions.
For the std poly etch (150 mT, 375W, 50/50 SF6/C2ClF5), we
measured a 17% (1670 A/min vs 1340 A/min undopedpoly) increased 
etch rate  compared to the value in the book. To get the exact same results
as before, I expect you  will need to cut the power 10 to 15%. We will br testing
all the std process for etch rate and sel.
3. The gas flow meters need recalibration. Using a rate of pressure
increase, we found that a SF6 flow readout of 53sccm gives the same
flow as C2ClF5 with a flow readout of 50 sccm. We will be doing this
recalibration in the weeks to come. For now for the poly etch process,
use 53 sccm of SF6 and 50 sccm of C2ClF5.
I will try to keep you informed as I have new info. I expect you will be seeing
etch results from the tool.
Thanks,	Jim McVittie
ps. Be sure to thank Len and Henry for all thier work on the tool. 

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