LAMpoly update 04/12/02

Len Booth booth at snf.stanford.edu
Fri Apr 12 13:11:56 PDT 2002


LAMpoly users -
	The machine has been reasembled and all the gas 
flows have been calibrated.  I'm still waiting for a new
floppy drive controller card to arrive, but this does not
prevent current usage of the machine, as we ordinarily
use the hard disk for recipe storage & loading.
Last night kailash came in and tested the poly etch rate & uniformity. 
Below are his results:	Len
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I tested my dummies on Program 77 which is pretty much 
similar to Program 1 except for the main etch. the etch 
rates are similiar however.  In my last run (a couple 
of months back) with this process, I had an etch
rate for doped poly around 2500 A /min. For the test 
wafers I set the time for the overetch at 0 s.

        Test Wafer 1:
thicknesses of p+ doped poly before and after etch

                T       L        C      B       R
before etch     3538    3565    3565    3550    3578
After 30s etch  2200    2187    2205    2213    2213
        Average Etch rate  ~ 2600 A /min
        Also uniformity is pretty good

        Test Wafer 2
                T       L       C       b       R
before etc      3567    3602    3586    3594    3575
After 40s etch  1993    1960    1986    1993    1980

Average etch rate ~ 2400 A /min. Excellent unifority
I had another wafer with ~ 3000 A of poly. It took 
around 75 seconds to etch through (endpoint). which 	corresponds 2400 A
/min.

I also ran my main wafers (12) through. All of them 
look good and the etch times were very repeatable. The 
etch patterns look excellent.	
		Kailash



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