From shott at snf.stanford.edu Sat Aug 2 16:44:15 2008 From: shott at snf.stanford.edu (shott at snf.stanford.edu) Date: Sat, 2 Aug 2008 16:44:15 -0700 Subject: Problem AG4108 SNF 2008-06-13 21:14:48: Temperature Faults Message-ID: Preliminary investigation of this problem: We got some replacement overtemp snap switches from AllWin. I mounted some of them on an aluminum block with silicone heat sink compound and then also placed one of the in-use ones (the most readily accessible top plate unit) on the same block. I then heated the aluminum block on the digital hot plate in litho in 5 deg C increments. All three switches tripped at an indicated hot plate temperature of 75 degrees C within 1 degree C. I was surprised how close they were. The replacement ones seem to indicate a trip point of 150F which is about 65C. In any event, I think that our premature over temp is NOT a temperature switch problem and is likely indicative of a real cooling problem. As soon as we can, I would like to place flow meters temporarily in each of the 7 cooling legs that run in parallel to see how the 2-2.5 gal/min cooling flow is divided amongst the 7 paths. My guess is that it is not terrribly even. John From shott at snf.stanford.edu Sat Aug 2 16:54:24 2008 From: shott at snf.stanford.edu (shott at snf.stanford.edu) Date: Sat, 2 Aug 2008 16:54:24 -0700 Subject: Shutdown AG4108 SNF 2008-07-30 22:42:57: plate overtemp... Message-ID: This is a "provisional" clear of the shutdown condition. I did find that the chiller had tripped due to evaporation in the reservior and it has been refilled and turned back on. Because we had some replacment temperature click switches from AllWin,, I also did a comparison of their trip point relative to that of the installed trip switches thinking that they might be tripping too early. As described below, that is not the case so we need to look more carefully at the coolant flow in the 7 parallel cooling lines to see if one or more are starved ... Preliminary investigation of this problem: We got some replacement overtemp snap switches from AllWin. I mounted some of them on an aluminum block with silicone heat sink compound and then also placed one of the in-use ones (the most readily accessible top plate unit) on the same block. I then heated the aluminum block on the digital hot plate in litho in 5 deg C increments. All three switches tripped at an indicated hot plate temperature of 75 degrees C within 1 degree C. I was surprised how close they were. The replacement ones seem to indicate a trip point of 150F which is about 65C. In any event, I think that our premature over temp is NOT a temperature switch problem and is likely indicative of a real cooling problem. As soon as we can, I would like to place flow meters temporarily in each of the 7 cooling legs that run in parallel to see how the 2-2.5 gal/min cooling flow is divided amongst the 7 paths. My guess is that it is not terrribly even. John From emyers at snf.stanford.edu Mon Aug 18 15:24:41 2008 From: emyers at snf.stanford.edu (emyers at snf.stanford.edu) Date: Mon, 18 Aug 2008 15:24:41 -0700 Subject: Problem AG4108 SNF 2008-08-18 15:24:41: Restarted system Message-ID: Restarted system, initiallized robot and topped off and started heat exchanger. From jackson at snf.stanford.edu Tue Aug 26 19:52:45 2008 From: jackson at snf.stanford.edu (jackson at snf.stanford.edu) Date: Tue, 26 Aug 2008 19:52:45 -0700 Subject: Shutdown AG4108 SNF 2008-08-26 19:52:45: pate overtemp after every wfr Message-ID: tried 3 wafers and had to reset switches after every wafer From eenriquez at snf.stanford.edu Thu Aug 28 12:29:38 2008 From: eenriquez at snf.stanford.edu (eenriquez at snf.stanford.edu) Date: Thu, 28 Aug 2008 12:29:38 -0700 Subject: Comment AG4108 SNF 2008-08-28 12:29:38: Update Message-ID: Increased the cooling CDA pressure from 80 psi to over 100 psi. Asked Ed to run some test wafers. From emyers at snf.stanford.edu Fri Aug 29 13:56:21 2008 From: emyers at snf.stanford.edu (emyers at snf.stanford.edu) Date: Fri, 29 Aug 2008 13:56:21 -0700 Subject: Problem AG4108 SNF 2008-08-29 13:56:20: Temperature Failures Message-ID: An adjustment was made to the oven air cooling. This may or may not have solved the over temperature problem. I am changing the system to a yellow light for the long weekend, but please be careful with your wafers. From emyers at snf.stanford.edu Fri Aug 29 13:56:28 2008 From: emyers at snf.stanford.edu (emyers at snf.stanford.edu) Date: Fri, 29 Aug 2008 13:56:28 -0700 Subject: Shutdown AG4108 SNF 2008-08-26 19:52:45: pate overtemp after every wfr Message-ID: An adjustment was made to the oven air cooling. This may or may not have solved the over temperature problem. I am changing the system to a yellow light for the long weekend, but please be careful with your wafers.