From booth at snf.stanford.edu Wed Apr 11 15:17:16 2001 From: booth at snf.stanford.edu (Len Booth) Date: Wed, 11 Apr 2001 15:17:16 -0700 Subject: LAMpoly downtime Message-ID: <3AD4D7EC.E7DC4DCC@snf.stanford.edu> LAMpoly users - The LoadLock pump needs to be repaired in the near future. It will require a maximum repair time of 5 working days. I would like to schedule this to start next Wednesday April 18th. If this is a problem for anyone, please respond to me by Monday April 16th. thanks, Len From booth at snf.stanford.edu Thu Apr 12 07:19:44 2001 From: booth at snf.stanford.edu (Len Booth) Date: Thu, 12 Apr 2001 07:19:44 -0700 Subject: LAMpoly downtime - update 04/12/01 Message-ID: <3AD5B980.843C4421@snf.stanford.edu> LAMpoly users - I received feedback from several users saying they need to use the machine through next week. To allow their processing to be finished, I will schedule the shutdown for LAMpoly for the week of April 23 - 27, . I've used CORAL to reserve this time. Len From mcvittie at cis.Stanford.EDU Thu Apr 12 18:11:44 2001 From: mcvittie at cis.Stanford.EDU (Jim McVittie) Date: Thu, 12 Apr 2001 18:11:44 -0700 (PDT) Subject: Seeing High Oxide Etch Rates Need Old Rates Message-ID: Lam Users, We are experiencing higher oxide etch rates than normal for both the HBr/Cl2/O2-He and HBr/O2-He processes. My first thought was that we are see a fluorine (F) memory affect where F comes off the chamber walls for some time after the plasma clean. However, the oxide etch rate is coming down a lot slower than I expected after a plasma clean that I did this morning. After well over an hour of seasoning with HBr/Cl2/O2-He and HBr/O2-He processes, Theresa Kramer still had a problem stopping on a 90 A of oxide under poly for a process that use to work with no problems. This morning when I was doing my tests, the oxide etch rate after about 30 min of seasoning was around 110 A/min during the main etch step for the std poly etch process (#1). When I orginially set up the Lam, the etch rate for this step was only 35 A /min. If you have measured any oxide etch rates on the Lam during the last year or so, can you please rates and process used. Thanks, Jim -------------------------------------------------------------- James P. McVittie Senior Research Scientist Allen Center for Integrated Systems jmcvittie at stanford.edu Stanford University Tel: (650) 725-3640 Rm. 336, 330 Serra Mall Fax: (650) 723-4659 Stanford, CA 94305-4075 From mcvittie at cis.Stanford.EDU Fri Apr 13 14:25:46 2001 From: mcvittie at cis.Stanford.EDU (Jim McVittie) Date: Fri, 13 Apr 2001 14:25:46 -0700 (PDT) Subject: Problems with Thick Resist in Etchers Message-ID: Lam, P5000, and Amtetcher Users, We just had major problems in both the Lam and P5000 due a user etching wafers with thick resist on them. Both machines were brought down and needed complete manual chamber cleans. PLEASE FOLLOW THE RULES and stay with thin resist (< 2 um) for wafers going into the Lam, P5000, and Amtetcher. Thanks, Jim -------------------------------------------------------------- James P. McVittie Senior Research Scientist Allen Center for Integrated Systems jmcvittie at stanford.edu Stanford University Tel: (650) 725-3640 Rm. 336, 330 Serra Mall Fax: (650) 723-4659 Stanford, CA 94305-4075 From mcvittie at cis.Stanford.EDU Mon Apr 16 17:54:59 2001 From: mcvittie at cis.Stanford.EDU (Jim McVittie) Date: Mon, 16 Apr 2001 17:54:59 -0700 (PDT) Subject: Status of Oxide etch rates in Lampoly Message-ID: Lam Users, The oxide etch rate have come down a bit but they are still higher than they should be. I now feel that the problem is that we have a carbon source in the chamber. In CL2 and HBr processes carbon is needed for the etching of oxide. The purpose He-O2 flow that we add to the standard poly process is to remove carbon during the etch. Normally, 5 sccm of 20% O2 in He is suffice to remove carbon coming from the resist mask. However, if there is another carbon source in the chamber, 5 sccm may not be enough. The problem with adding too much O2 is that the resist etch rate goes up with O2 flow. Note that the oxide etch rate normally goes down faster than the resist etch rate goes up. About a month ago when I last saw the inside of the chamber, I noticed a black buildup on the top dielectric between the ICP coil and the chamber. I now suscept this layer is carbon or a carbon mixture. The etch rates below support a carbon source in the chamber in that the ox etch is coming down as the He-O2 flow is increased. We have several choices in what to do about this black layer which are: 1. Do nothing and live with the higher oxide etch rates. O2 plasma clean should help but too much O2 cleaning will destory the system o-rings and the system plasma. 2. Sand blast the layer off. 3. Turn over dielectric so that the black layer is on the outside toward the coil. Note that this dielectric is about an inch thick and 12 inches in diameter. 4. Get a new dielectric. We have an old style dielectric in that ours is made of aluminia ceramic while Lam currently uses quartz which reduced aluminum contamination to the wafers. Since no one has been complaining about Al contamination in the Lam, my choice is to sand blast the dielectric. I would be interested in hearing what you think about this. Here are the results that Brian Green got today using recipe #1. Program #1 Main Etch only (no BT or OE) He-O2 = 0 sccm -> SiO2 etch rate = 220 A/min He-O2 = 3 sccm -> SiO2 etch rate = 212 A/min He-O2 = 5 sccm -> SiO2 etch rate = 184 A/min <- Normal Program #1 O2 flow He-O2 = 10 sccm -> SiO2 etch rate = 167 A/min Program #1 Over Etch only (no BT or ME) He-O2 = 5 sccm -> SiO2 etch rate = 46 A/min <- Normal Program #1 O2 flow Note: All wafers etched for 2 minutes I will try to more data as the week goes on. When we initially set up the Lam, the ox etch rate during the main etch was only 35 A/min and during the OE it was 26 A/min. However, we have been runnig high for some time. Jim McVittie From aaronp at micromachine.stanford.edu Mon Apr 16 18:56:18 2001 From: aaronp at micromachine.stanford.edu (Aaron Partridge) Date: Mon, 16 Apr 2001 18:56:18 -0700 Subject: Status of Oxide etch rates in Lampoly In-Reply-To: References: Message-ID: lam folks, sandblasting the dielectric sounds reasonable, or perhaps we can find a company that will chemical or furnace clean it for us. i am also ok with running O2 cleans and eating the seals -- if that works then it seems a viable solution. i am not enthusiastic about changing the etch processes; i would like to keep process #1 as we now have it since i have experience with the resultant profiles and etch rates. one other solution -- cannibalize the alumina plate in lamsi. this might not be as bad as it sounds. if we ever get lamsi running for deep silicon etching it will need a quartz plate anyhow. aaron. >Lam Users, > >The oxide etch rate have come down a bit but they are still higher than >they should be. I now feel that the problem is that we have a carbon >source in the chamber. In CL2 and HBr processes carbon is needed for the >etching of oxide. The purpose He-O2 flow that we add to the standard poly >process is to remove carbon during the etch. Normally, 5 sccm of 20% O2 in >He is suffice to remove carbon coming from the resist mask. However, if >there is another carbon source in the chamber, 5 sccm may not be enough. >The problem with adding too much O2 is that the resist etch rate goes up >with O2 flow. Note that the oxide etch rate normally goes down faster than >the resist etch rate goes up. About a month ago when I last saw the inside >of the chamber, I noticed a black buildup on the top dielectric between >the ICP coil and the chamber. I now suscept this layer is carbon or a >carbon mixture. The etch rates below support a carbon source in the >chamber in that the ox etch is coming down as the He-O2 flow is increased. >We have several choices in what to do about this black layer which are: > >1. Do nothing and live with the higher oxide etch rates. O2 plasma clean >should help but too much O2 cleaning will destory the system o-rings and >the system plasma. > >2. Sand blast the layer off. > >3. Turn over dielectric so that the black layer is on the outside toward >the coil. Note that this dielectric is about an inch thick and 12 inches >in diameter. > >4. Get a new dielectric. We have an old style dielectric in that ours is >made of aluminia ceramic while Lam currently uses quartz which reduced >aluminum contamination to the wafers. > >Since no one has been complaining about Al contamination in the Lam, my >choice is to sand blast the dielectric. I would be interested in hearing >what you think about this. > >Here are the results that Brian Green got today using recipe #1. > >Program #1 Main Etch only (no BT or OE) >He-O2 = 0 sccm -> SiO2 etch rate = 220 A/min >He-O2 = 3 sccm -> SiO2 etch rate = 212 A/min >He-O2 = 5 sccm -> SiO2 etch rate = 184 A/min <- Normal Program #1 O2 flow >He-O2 = 10 sccm -> SiO2 etch rate = 167 A/min > >Program #1 Over Etch only (no BT or ME) >He-O2 = 5 sccm -> SiO2 etch rate = 46 A/min <- Normal Program #1 O2 flow > >Note: All wafers etched for 2 minutes > >I will try to more data as the week goes on. > >When we initially set up the Lam, the ox etch rate during the main etch >was only 35 A/min and during the OE it was 26 A/min. However, we have been >runnig high for some time. > > Jim McVittie From bgreene at stanford.edu Thu Apr 19 11:36:55 2001 From: bgreene at stanford.edu (Brian Joseph Greene) Date: Thu, 19 Apr 2001 11:36:55 -0700 (PDT) Subject: Particle problem resolved Message-ID: Folks, Len took the lampoly apart and performed a wet clean of both loadlock chambers and the etch chamber. (Thanks Len!) Last night, I ran the post-wet clean procedure and inspected several wafers for particles. At the end of the procedure, I ran 15 bare silicon wafers through Etch #1 (ME=60s OE=60s) to season the chamber. Close observation of the last few wafers revealed no particles with the un-aided eye, and less than 8 particles per wafer were visible by eye under the UV lamp. There were no particles visible under the microscope with 5x dark field setup. When I ran 15 silicon wafers through the system this morning, I found the number of particles had doubled. I would recommend that users inspect their seasoning wafers carefully. All of my seasoning wafers looked good to the unaided eye, but the particles were very apparent when the wafers were placed under the UV lamp. The lamp is now located behind the Gryphon. Please use it to inspect your wafers, and record unusual particle counts in the log book. -Brian _____________________________________________________________ Brian J. Greene Office: CIS-X 128X Applied Physics Dept, MC 4090 Phone: (650) 723-4194 ext 5 Stanford University Pager: (650) 354-9687 Stanford, CA 94305-4090 Fax: (650) 723-4659 From booth at snf.stanford.edu Fri Apr 20 14:05:43 2001 From: booth at snf.stanford.edu (Len Booth) Date: Fri, 20 Apr 2001 14:05:43 -0700 Subject: LAMpoly shutdown reminder Message-ID: <3AE0A4A7.AFC09A15@snf.stanford.edu> LAMpoly users - This is to remind everyone that I've reserved time, and scheduled a shutdown for our LAMpoly for next week. This will start Monday morning. The purpose is to repair one of the vacuum pumps as it's leaking oil quite badly. Len From booth at snf.stanford.edu Fri Apr 20 16:21:50 2001 From: booth at snf.stanford.edu (Len Booth) Date: Fri, 20 Apr 2001 16:21:50 -0700 Subject: LAMpoly - update on particles, Friday 04/20 Message-ID: <3AE0C48E.DBE9D19@snf.stanford.edu> LAMpoly users - Here's the latest info provided by Brian Greene; He has been inspecting wafers using the UV lamp: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - My update on the particle generation in lampoly: Inspecting my wafers before seasoning -> 2 particles or less per wafer Inspecting my wafers after seasoning -> 8 particles or less per wafer It didn't seem to be getting any better or worse with the number of wafers run through the system. I ran 15 seasoning wafers, and 1 polysilicon wafer. -Brian From booth at snf.stanford.edu Tue Apr 24 15:48:35 2001 From: booth at snf.stanford.edu (Len Booth) Date: Tue, 24 Apr 2001 15:48:35 -0700 Subject: LAMpoly shutdown update 04/24/01 Message-ID: <3AE602C3.A6DC360C@snf.stanford.edu> Users - Brian & Aaron finished their work about 10am this morning, so I did not start the shutdown for repair of the LoadLock pump until then. Best estimate currently is that the pump will be returned to us next Tuesday May 1st.