From mtang at snf.stanford.edu Fri Jul 5 17:25:51 2002 From: mtang at snf.stanford.edu (Mary Tang) Date: Fri, 05 Jul 2002 17:25:51 -0700 Subject: Contamination Message-ID: <3D26390F.69854D03@snf.stanford.edu> A labmember processed glass wafers (which contain 5-7% sodium and trace metals) through both wbnonmetal (4 pm) and wbdiff (4:30 pm) on July 2. The problem was not discovered until later. Both benches were decontaminated the evening of July 3. Mary -- Mary X. Tang, Ph.D. National Nanofabrication Users' Network Stanford Nanofabrication Facility CIS Room 136, Mail Code 4070 Stanford, CA 94305 (650)723-9980 mtang at snf.stanford.edu From eadensaw at hotmail.com Tue Jul 9 22:04:40 2002 From: eadensaw at hotmail.com (Eaden Saw) Date: Tue, 9 Jul 2002 22:04:40 -0700 Subject: Pyrex wafers were process at this station on 7/1/02 Message-ID: This is to inform you that pyrex wafers were inadvently cleaned in the Pirahna batch and etched in 6:1 BOE tank on 7/1/02. I am sorry for any inconvenience this might have caused you. Eaden -------------- next part -------------- An HTML attachment was scrubbed... URL: From mtang at snf.stanford.edu Wed Jul 10 17:19:54 2002 From: mtang at snf.stanford.edu (Mary Tang) Date: Wed, 10 Jul 2002 17:19:54 -0700 Subject: Sodium Contamination Incident Message-ID: <3D2CCF2A.10CE5ACC@snf.stanford.edu> As you may have seen in the previous group wbnonmetal email message, pyrex was mistaken for quartz and processed through the wbnonmetal 6:1 BOE tank on Monday, July 1, at about 5:30 pm. The 6:1 BOE was changed on Tuesday, July 2, around 1:40 pm. On Wednesday evening, Eric P, acting on several suspicious clues, took the initiative to decontaminate this and other stations. The contamination was confirmed today. If you have processed sensitive device materials through the 6:1 BOE tank since Monday evening, your materials may face some risk of contamination by sodium and other trace metals. This risk should, however, be minimized, by following standard cleaning procedures before any high temperature processing steps (i.e., wbdiff clean). If you are concerned about your materials, please consult with Jim McVittie, as he has much experience and information with contamination issues. I am sorry this incident occurred. We will gladly work with you to address your concerns. Mary -- Mary X. Tang, Ph.D. National Nanofabrication Users' Network Stanford Nanofabrication Facility CIS Room 136, Mail Code 4070 Stanford, CA 94305 (650)723-9980 mtang at snf.stanford.edu From mtang at snf.stanford.edu Thu Jul 18 14:18:03 2002 From: mtang at snf.stanford.edu (Mary Tang) Date: Thu, 18 Jul 2002 14:18:03 -0700 Subject: Decontamination Message-ID: <3D37308B.2CA7FEBD@snf.stanford.edu> Hi all -- wbnonmetal was inadvertently contaminated with NaOH earlier today. The perpetrator is admirably taking full responsibility and decontaminating the bench now (many thanks!) The bench will be down for a couple of hours. Let this be a lesson - please always read the labels on the chemicals, even when you are "sure" of what you have. And please always put chemicals away in their proper place -- do not leave them in carts. Thanks for your attention. Mary -- Mary X. Tang, Ph.D. National Nanofabrication Users' Network Stanford Nanofabrication Facility CIS Room 136, Mail Code 4070 Stanford, CA 94305 (650)723-9980 mtang at snf.stanford.edu From mtang at snf.stanford.edu Thu Jul 18 14:19:22 2002 From: mtang at snf.stanford.edu (Mary Tang) Date: Thu, 18 Jul 2002 14:19:22 -0700 Subject: Decontamination Message-ID: <3D3730DA.76EE968D@snf.stanford.edu> oops. I meant potassium hydroxide, not NaOH. M -- Mary X. Tang, Ph.D. National Nanofabrication Users' Network Stanford Nanofabrication Facility CIS Room 136, Mail Code 4070 Stanford, CA 94305 (650)723-9980 mtang at snf.stanford.edu From kliu at molecularreflections.com Fri Jul 19 13:18:37 2002 From: kliu at molecularreflections.com (Kelvin Liu) Date: Fri, 19 Jul 2002 13:18:37 -0700 Subject: 20:1 BOE tank has 6:1 BOE Message-ID: <0729B7BC9F9936469783A001D36D178D0188DE@mrserver.molecularreflections.loc> I've put 6:1 BOE in the 20:1 BOE tank at wbnonmetal since the 6:1 tank has contamination issues. I just wanted to make other labmembers aware of this. There is also a sign taped above the pot as an additional reminder. - Kelvin Liu From mcvittie at snf.stanford.edu Fri Jul 19 17:55:49 2002 From: mcvittie at snf.stanford.edu (Jim McVittie) Date: Fri, 19 Jul 2002 17:55:49 -0700 Subject: Results of testing Wet Benches for Sodium Message-ID: <3D38B515.E2D3AE44@snf.stanford.edu> Wet bench Users, As part of the clean up after the Pyrex glass wafer went through WBdiff and Wbnonmetal, we did a series of sodium contamination tests. For these tests, we exposed clean 1000A oxide Si wafers to the HF baths in WBdiff and Wbnonmetal, fabricated alumimum gate capaciators and tested for Na using the Bias Temperature Stress (BTS) CV method. In addition, to testing the HF baths, we also tested the effect of dipping clean oxide wafers into a container of 50:1 HF, which had been exposed to a Pyrex wafer for 2 minutes. The expectation was that the Pyrex wafer would contaminate the bath with Na and pass on the Na to following clean wafers going through the bath. The results were surprized good, in that not only did the HF tanks in the wet benches show no contamination, the wafer from the intensionally contaminated HF container also showed no Na contamination to the oxide wafers. In all cases, the mobile ion level was found to be below 5E10/cm2 which is quite good. The conclusions are that the HF tanks in the wet benches were successfully decontaminated, and that low levels of Na in a HF bath does not came out of solution onto clean oxide surfaces. These results also say that the other parts of our lab needed for these MOS capacitors are all in good shape in term of mobile ion contamination. These other parts include: the furnaces (Tylan #1 and #7, the DI water system, the WBdiff bench with the HF tanks from the WBsilicide, the Gryphon sputter deposition system, the litho area, the Wbmetal bench, the spin dryers and the Tylan FGA tube. Thanks for all your cooperation in help to keep the lab contamination free. Jim McVittie From SamS at LSInc.biz Mon Jul 22 12:48:57 2002 From: SamS at LSInc.biz (Samuel B. Schaevitz) Date: Mon, 22 Jul 2002 12:48:57 -0700 Subject: Contamination Repayment Message-ID: <5.0.2.1.2.20020722123805.0328c450@pop.lilliputiansystemsinc.com> Hey All, As you know, the wbnonmetal bench was down last Thursday afternoon because of me. While Mary has me doing some stuff for the lab, that doesn't help any of you who were inconvenienced by the shutdown. So, I would like to offer my processing services to those of you who were disrupted last week. I will be in the lab all day Wednesday, Thursday and Friday. E-mail me to reserve my time, or grab me in the lab, and I would love to apologize by running and/or babysitting some of your processing. I am qualified on most of the equipment in the lab, and I promise not to screw up your wafers, or the equipment. --Sam ------------------------------------------------------ Samuel B. Schaevitz Lilliputian Systems, Inc. 6 Keenan Drive Winchester, MA 01890 E-Mail: SamS at LSInc.biz Mobile: (617) 543-5875