Comment AG4108 SNF 2009-06-30 17:31:20: Process Qual but with Over Temp error during qual

[nvgirish at snf.stanford.edu]

Hi 
  I ran a process qual (1150C, 30sec recipe) with 5 wbdiff cleaned bare silicon wafers. 4 wafers ran fine; for the 5th the error "Over Temp of Plate" occurred. This problem has been persistent for a long time; despite all the servicing & repair. Is it a water cooling problem?
Ran the 5th wafer after waiting for some time for the chamber to cool. 
The results are as follows (Rudolph ellipsometer 5pt measurement):
After this ran 12 wafers at 1000C, 30 sec with no problem.
Wafer# 	 	                    Avg.	  Std. dev
1	95.1  86.9  98.4  89.9  100   94.3   5.8
2	119  114  126  113  124       119    5.4
3	125 119 131 120 132            126   5.8
4	131 124 136 127 135            131   4.9
5	124 119 130 123  130           125   4.5
Please look into the over temp problem.
Girish