Comment lampoly SNF 2010-09-09 15:51:00: Load/tune adjustments

mtang at mtang at
Thu Sep 9 15:51:00 PDT 2010

Xuan Wu reported plasma instability problems.  The system does not tune SF6 plasma well.  However, it also had problems with good old recipe 1.  So, I adjusted the tune and load settings for top RF in recipes 1 & 2 as follows:
Step 3:  Old 18000/10000 -> new 23000/12000
Step 5:  Old 14000/19000 -> new 21000/19000
Step 7:  old 14000/23000 -> new 19000/23000
Recipe 25:
Same as above
Recipe 90:
Step 3 as above
Step 5:  14000/20000 -> 21000/20000
Step 7:  14000/20000 -> 20000/20000
Recipe 99 is the high power SF6 plasma (600W) -- reflected power is non-zer, but below 5%.
Recipe 80/180 is Nahid's isotropic etch -- could not control reflected power very well.  One version had 25 sccm of He -- this could not control at all.  Removing the He (another version) improved reflected power, but it was still about 15% of range.
The tune presets are very different from a month ago when we last looked at them.  I think maybe the upper electrode RF match needs to be examined.
The recipes that were logged as being used in the last two months were adjusted.  If you have another recipe that needs to be adjusted/tested, please let Usha or me know.  If you are using SF6 only, please be aware of unstable plasma problems.  If you observe problems, note which recipe you are using and which step is showing problems.

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