From eenriquez at snf.stanford.edu Wed May 11 15:26:41 2011 From: eenriquez at snf.stanford.edu (eenriquez at snf.stanford.edu) Date: Wed, 11 May 2011 15:26:41 -0700 Subject: Comment stsetch2 SNF 2011-05-11 15:26:40: Update chuck temp Message-ID: Installed a TC at the output of the platen (first connector at the output of the feedthru box). The temperature at the output reads 25 C when the input temperature is 10 C. I ran the "KY SOI etch Ver2" for 30 minutes with no increase in the coolant output temperature. From mcvittie at snf.stanford.edu Tue May 17 10:44:34 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Tue, 17 May 2011 10:44:34 -0700 Subject: Shutdown stsetch2 SNF 2011-05-17 10:44:33: No Flow from coil chiller Message-ID: The coil temperature has come up from 20C to 26C so it looks like it is not the flow switch this time . Maybe the coolant is low? Jim From eenriquez at snf.stanford.edu Tue May 17 11:25:33 2011 From: eenriquez at snf.stanford.edu (eenriquez at snf.stanford.edu) Date: Tue, 17 May 2011 11:25:33 -0700 Subject: Shutdown stsetch2 SNF 2011-05-17 10:44:33: No Flow from coil chiller Message-ID: Reset the coil chiller's pump From grahamab at snf.stanford.edu Wed May 18 13:22:33 2011 From: grahamab at snf.stanford.edu (grahamab at snf.stanford.edu) Date: Wed, 18 May 2011 13:22:33 -0700 Subject: Shutdown stsetch2 SNF 2011-05-18 13:22:32: extreme grass formation Message-ID: running a recipe that has been bulletproof in the past and was perfectly adequate just a few weeks ago. I have doublechecked all recipe parameters, but I am now getting grass formation even in 2um wide trenches (confirmed with more than one wafer even after increasing the etch time to supress grass formation). something is severely off on the tool. gas flow rates and power settings were all correct during the etch. photoresist etch rate also appears to have decreased (by a factor of two from ~1 month ago) From mcvittie at snf.stanford.edu Wed May 18 17:15:24 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Wed, 18 May 2011 17:15:24 -0700 Subject: Comment stsetch2 SNF 2011-05-18 17:15:23: Grass Problem Message-ID: Compared datalog files for today's SIO recipe run with grass with run using same recipe but run a month ago. Could find no significant differeances between the runs except for platin temperature, which is now running at 14C and should be 10C. Have asked Elmer to correct the platin temperature problem. Also ran the SIO recipe to look at the low freq pulsing. Pulse generator is correctly set at 20% duty cycle and low frequency bias power is being correctly modulated. Will run test wafers tomorrow to see if I can reproduce the problem on my wafers. Jim From mislam at snf.stanford.edu Wed May 18 22:20:24 2011 From: mislam at snf.stanford.edu (mislam at snf.stanford.edu) Date: Wed, 18 May 2011 22:20:24 -0700 Subject: Comment stsetch2 SNF 2011-05-18 22:20:23: Can we remove the shutdown status? Message-ID: So that users who run regular recipes could test our recipes and run the tool at our own risk. Problem seems to be with the SOI recipes as I understand from Jim's comments. From mcvittie at snf.stanford.edu Fri May 20 18:38:05 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Fri, 20 May 2011 18:38:05 -0700 Subject: Problem stsetch2 SNF 2011-05-20 18:38:05: STS2 Backing pump Shut Down Message-ID: Turbo backing pump shutdown and will not startup using pump-to-base command. Manually turned off and on power to pump in basement but hadeffect on startup. Jim From mcvittie at snf.stanford.edu Tue May 24 12:16:36 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Tue, 24 May 2011 12:16:36 -0700 Subject: Problem stsetch2 SNF 2011-05-20 18:38:05: STS2 Backing pump Shut Down Message-ID: The problem was caused by a short of a 24Vdc line at the sense switch on the by-pass vacuum valve for the chamber. He system still needs to be checked out and all the heaters need to be turneed and brought up to steady state temperature. I expect the system to be back up by late afternoon. Jim From mcvittie at snf.stanford.edu Tue May 24 12:18:33 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Tue, 24 May 2011 12:18:33 -0700 Subject: Comment stsetch2 SNF 2011-05-24 12:18:32: Grass Issue Message-ID: In my note I forgot that we still need to finish looking at the grass problem. I will look at this problem once the system is back up to temperature. Jim From mcvittie at snf.stanford.edu Tue May 24 18:17:58 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Tue, 24 May 2011 18:17:58 -0700 Subject: Shutdown stsetch2 SNF 2011-05-18 13:22:32: extreme grass formation Message-ID: I am not seeing a grass for the Jim-Etch-1 recipe which uses hi freq bias and a fixed throttle (16%) position (13/40 mT) for 6 min. But I am seeing a "black silicon" suface for the SOI HAR GC3-1 recipe which uses low freq bias (85w) with auto pressure control (12/26mT) and 2.5 EM current for 5 min. I am removing the shutdown since my recipe does not show grass. I will continue to look at what is going on with the SOI recipe. Jim From mcvittie at snf.stanford.edu Thu May 26 11:04:33 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Thu, 26 May 2011 11:04:33 -0700 Subject: Comment stsetch2 SNF 2011-05-26 11:04:33: STS2 Wafer Temperature Problem Message-ID: We still have a significant wafer temperature problem. For the last 3 months or so I have consistently found the wafer temperature to be over 99C when I run the std STS temperature test recipe. Note that the STS spec is T < 77C, and we were running at a peak wafer temperature of 71C before this problem began. I ran the temp test again yesterday and again got T > 99C. I also did a test of my temperature indicator labels on a digital hotplate and found they are accurate to within 1C. The main process impact of the higher temperature is lower resist selectivity. The resist etch rate is running at about 2.5 times higher than it did before the problem. A month or so ago, we found that the problem is not the lip seal or the backside He in that a wafer put on to the chuck after a test run indicated the chuck was over 70C, so the whole chuck is getting hot and staying hot for some time after a run. The chuck assembly consists of the wafer, the lip seal, the chuck, a indium heat transfer gasket, a copper block with passages for coolant flow and the connection to the coolant system. We have placed a TCs on both the incoming and outgoing coolant lines. The outgoing coolant only increases by 0.9C during a test run where the wafer temperature increases from 0C to over 99C. So the problem is either in the way we have installed the indium gasket or in how the chuck is insulated from other heat sources in the chamber. Note that the chamber has a number of heaters to control polymer deposition. Tomorrow, my plan is to open the chamber, to look at the indium gasket, process kit (the insulators around the chuck) and to measure the temperature around the chuck. We have contacted STS for them to come out and look at this problem. Jim From mcvittie at snf.stanford.edu Sat May 28 01:28:55 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Sat, 28 May 2011 01:28:55 -0700 Subject: Comment stsetch2 SNF 2011-05-26 11:04:33: STS2 Wafer Temperature Problem Message-ID: I have the peak wafer temperature down from 110C to 77C. The problem was the indium gasket. I cleaned up the outer gasket and reduced the center gasket from 3 stacked on top of each other to a single gasket. I should be able to get the temperature down further by using new gaskets. By the way the He leak rate was 9 mT/min which is high. Reducing this leak rate should also help lower the temperature. Jim From mcvittie at snf.stanford.edu Sat May 28 11:53:00 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Sat, 28 May 2011 11:53:00 -0700 Subject: Comment stsetch2 SNF 2011-05-18 22:20:23: Can we remove the shutdown status? Message-ID: The shutdown was removed on the 18th. Jim From mcvittie at snf.stanford.edu Sat May 28 11:53:27 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Sat, 28 May 2011 11:53:27 -0700 Subject: Comment stsetch2 SNF 2011-05-24 12:18:32: Grass Issue Message-ID: From mcvittie at snf.stanford.edu Sat May 28 12:30:05 2011 From: mcvittie at snf.stanford.edu (mcvittie at snf.stanford.edu) Date: Sat, 28 May 2011 12:30:05 -0700 Subject: Comment stsetch2 SNF 2011-05-28 12:30:05: Solved STS2 Wafer Temperature Problem Message-ID: I wrote a report/comment last night which I can not find listed so here is a repeat. Yesterday (Friday) I opened up the chamber and took apart the chuck assembly, which is not a hard task. I focused on the two indium gaskets under the chuck which transfer heat from the chuck to the cooled copper block below. In the center, I found 3 indium gaskets stacked on top of each other. I remove all of them and put the best of the 3 back in the center position. The edge gasket was in bad shape. I removed it in 2 pieces. After smoothing it, I put it back in the edge position. I reassembled evedrything, pumped the system down, did a O2 clean and run a dummy run of the temperature test recipe. I than did the 15 min temperature test using a wafer with temperature indicator labels ranging from 71C to 121C. Since March, this test has consistently given peak wafer temperatures above 100C. After cleaning up the indium gaskets and going to a single center gasket, I got a peak wafer temperature of 77C. It is at the limit of the STS spec but it is a great improvement over what I have seen seen for the tool. Clearly, we need to a get a new set of gaskets and make sure they are installed properly. The He leak rate was 9 mT/min. Improving this leak rate should also reduce the wafer temp. I have also been monitoring a TC on the coolant coming out of the chuck. Until last night, I have been seeing a coolant tempap rise of 0.9C during my std temp test. After the change to the indium gasket, the coolant temp rise was 1.2 C. This shows that monitoring the coolant temp rise may be a good way of monitoring the wafer temperature. Jim