From hathaway at cns.fas.harvard.edu Thu Apr 5 15:09:04 2012 From: hathaway at cns.fas.harvard.edu (Mac Hathaway) Date: Thu, 5 Apr 2012 15:09:04 -0400 Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? Message-ID: <4F7DEDD0.8020202@cns.fas.harvard.edu> Hey all, What do folks currently consider satisfactory regarding the air-flow face velocity at their fume hoods and wet benches? Do you have any ASHRAE/ANSI/SEMI-type standards or references that you draw on for this purpose? The topic came up today in the context of energy savings, lab make-up air, and this sort of thing... Thanks, Mac Hathaway Harvard Center for Nanoscale Systems -------------- next part -------------- An HTML attachment was scrubbed... URL: From bill at eecs.berkeley.edu Thu Apr 5 21:22:40 2012 From: bill at eecs.berkeley.edu (Bill Flounders) Date: Thu, 05 Apr 2012 18:22:40 -0700 Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? In-Reply-To: <4F7DEDD0.8020202@cns.fas.harvard.edu> References: <4F7DEDD0.8020202@cns.fas.harvard.edu> Message-ID: <4F7E4560.5000703@eecs.berkeley.edu> Mac, Our EH&S treats our wet benches as fume hoods and requires face velocity of at least 100 feet per minute. 100 - 150 fpm is considered satisfactory. Several groups have been pushing for improved hood design to bring air flow requirements down to 60fpm. Lawrence Berkeley Lab has an extensive program in this area: http://ateam.lbl.gov/hightech/fumehood/fhood.html A summary report of "The Berkeley Hood" (not hoodie) is here: http://ateam.lbl.gov/hightech/fumehood/Publications.html Bottom Line - with improved hood design you can definitely decrease exhaust requirements and achieve significant savings. But it would not be prudent to just decrease the face velocity requirement and use that new lower standard with legacy equipment. If a new (decreased) standard is defined it will only apply to new equipment that meets a specific design requirement. Bill Flounders UC Berkeley NanoLab Mac Hathaway wrote: > Hey all, > > What do folks currently consider satisfactory regarding the air-flow > face velocity at their fume hoods and wet benches? Do you have any > ASHRAE/ANSI/SEMI-type standards or references that you draw on for > this purpose? > > The topic came up today in the context of energy savings, lab make-up > air, and this sort of thing... > > > Thanks, > > Mac Hathaway > Harvard Center for Nanoscale Systems > > > _______________________________________________ > labnetwork mailing list > labnetwork at mtl.mit.edu > https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork -------------- next part -------------- An HTML attachment was scrubbed... URL: From jmorgan at wilsonarch.com Fri Apr 6 10:11:41 2012 From: jmorgan at wilsonarch.com (Joe Morgan) Date: Fri, 6 Apr 2012 10:11:41 -0400 Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? In-Reply-To: <4F7DEDD0.8020202@cns.fas.harvard.edu> References: <4F7DEDD0.8020202@cns.fas.harvard.edu> Message-ID: <367EB89539C1EF4EA219A5FFE9E5C2B701A280CD@WWA-MAIL1.wwa.arch> Mac, See ANSI/AIHA Z9.5 for laboratory ventilation systems and worker health. In the past 100 feet/per minute has been the golden rule. However, for a number of years now fume hood manufacturers have created new designs that sometimes enable sash velocities as low as 60 feet/minute. The hood must still pass testing and certification as defined by ASHRAE 110. I'm not sure how wet process benches or laminar flow hoods fit into these standards. Best, Joe From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Mac Hathaway Sent: Thursday, April 05, 2012 3:09 PM To: Lab Network (labnetwork at mtl.mit.edu) Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? Hey all, What do folks currently consider satisfactory regarding the air-flow face velocity at their fume hoods and wet benches? Do you have any ASHRAE/ANSI/SEMI-type standards or references that you draw on for this purpose? The topic came up today in the context of energy savings, lab make-up air, and this sort of thing... Thanks, Mac Hathaway Harvard Center for Nanoscale Systems -------------- next part -------------- An HTML attachment was scrubbed... URL: From hathaway at cns.fas.harvard.edu Tue Apr 10 15:47:17 2012 From: hathaway at cns.fas.harvard.edu (Mac Hathaway) Date: Tue, 10 Apr 2012 15:47:17 -0400 Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? In-Reply-To: <367EB89539C1EF4EA219A5FFE9E5C2B701A280CD@WWA-MAIL1.wwa.arch> References: <4F7DEDD0.8020202@cns.fas.harvard.edu> <367EB89539C1EF4EA219A5FFE9E5C2B701A280CD@WWA-MAIL1.wwa.arch> Message-ID: <4F848E45.9070506@cns.fas.harvard.edu> Thanks to all for the helpful replies. At CNS, we are using 100 fpm on our fume hoods and wetbenchs, per ANSI. However, with the push for energy conservation, we're keeping our eyes open. It is interesting to note that the possibility of 60 fpm appears to be bench-specific. Has anyone tested their benches at this flow, successfully or not? Was this in a clean room (with vertical air flow?) Thanks again. Mac Hathaway Harvard Center for Nanoscale Systems On 4/6/2012 10:11 AM, Joe Morgan wrote: > > Mac, > > See ANSI/AIHA Z9.5 for laboratory ventilation systems and worker > health. In the past 100 feet/per minute has been the golden rule. > However, for a number of years now fume hood manufacturers have > created new designs that sometimes enable sash velocities as low as 60 > feet/minute. The hood must still pass testing and certification as > defined by ASHRAE 110. I?m not sure how wet process benches or > laminar flow hoods fit into these standards. > > Best, Joe > > *From:*labnetwork-bounces at mtl.mit.edu > [mailto:labnetwork-bounces at mtl.mit.edu] *On Behalf Of *Mac Hathaway > *Sent:* Thursday, April 05, 2012 3:09 PM > *To:* Lab Network (labnetwork at mtl.mit.edu) > *Subject:* [labnetwork] Face Velocity for Wet benches/Fume hoods? > > Hey all, > > What do folks currently consider satisfactory regarding the air-flow > face velocity at their fume hoods and wet benches? Do you have any > ASHRAE/ANSI/SEMI-type standards or references that you draw on for > this purpose? > > The topic came up today in the context of energy savings, lab make-up > air, and this sort of thing... > > > Thanks, > > Mac Hathaway > Harvard Center for Nanoscale Systems > -------------- next part -------------- An HTML attachment was scrubbed... URL: From rmorrison at draper.com Wed Apr 11 08:02:51 2012 From: rmorrison at draper.com (Morrison, Richard H., Jr.) Date: Wed, 11 Apr 2012 12:02:51 +0000 Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? In-Reply-To: <367EB89539C1EF4EA219A5FFE9E5C2B701A280CD@WWA-MAIL1.wwa.arch> References: <4F7DEDD0.8020202@cns.fas.harvard.edu> <367EB89539C1EF4EA219A5FFE9E5C2B701A280CD@WWA-MAIL1.wwa.arch> Message-ID: Hi, We are building a new fab and the current talk is whether we use variable speed fans with dampers that sense the pressure drop due to sash position or no control. We are looking at the projected cost savings vs the cost to install sensors, dampers, fans and control software. The control software expense is very high. Preliminary numbers are not in favor of the expense. The Draper EHS also treats fab hoods like fume hoods, so the requirement is 100 fpm at the open face. Rick From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Joe Morgan Sent: Friday, April 06, 2012 10:12 AM To: Mac Hathaway; labnetwork at mtl.mit.edu Subject: Re: [labnetwork] Face Velocity for Wet benches/Fume hoods? Mac, See ANSI/AIHA Z9.5 for laboratory ventilation systems and worker health. In the past 100 feet/per minute has been the golden rule. However, for a number of years now fume hood manufacturers have created new designs that sometimes enable sash velocities as low as 60 feet/minute. The hood must still pass testing and certification as defined by ASHRAE 110. I'm not sure how wet process benches or laminar flow hoods fit into these standards. Best, Joe From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Mac Hathaway Sent: Thursday, April 05, 2012 3:09 PM To: Lab Network (labnetwork at mtl.mit.edu) Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? Hey all, What do folks currently consider satisfactory regarding the air-flow face velocity at their fume hoods and wet benches? Do you have any ASHRAE/ANSI/SEMI-type standards or references that you draw on for this purpose? The topic came up today in the context of energy savings, lab make-up air, and this sort of thing... Thanks, Mac Hathaway Harvard Center for Nanoscale Systems -------------- next part -------------- An HTML attachment was scrubbed... URL: From rmorrison at draper.com Wed Apr 11 08:08:56 2012 From: rmorrison at draper.com (Morrison, Richard H., Jr.) Date: Wed, 11 Apr 2012 12:08:56 +0000 Subject: [labnetwork] Silicon Nitride question Message-ID: Hi Everyone, I am restarting a Silicon Nitride LPCVD process and I have a few questions. The process will use a EBARA dry pump therefore should I use a trap on the vacuum pump inlet to catch any particulate generated? Any issue with excess hydrogen from the process going into the dry pump, do I need a burn box on the vacuum pump exhaust? 2nd question has anybody tried to run the LPCVD process on a wafer with a platinum metal pattern on the surface? I was wondering if there maybe some adverse effect because of the catalytic nature of Platinum. Thanks Rick Rick Morrison Senior Member Technical Staff Group Leader Microfabrication Operations Draper Laboratory 555 Technology Square Cambridge, MA 02139 W 617-258-3420 C 508-930-3461 -------------- next part -------------- An HTML attachment was scrubbed... URL: From spaolini at cns.fas.harvard.edu Wed Apr 11 10:28:51 2012 From: spaolini at cns.fas.harvard.edu (Paolini, Steven) Date: Wed, 11 Apr 2012 10:28:51 -0400 Subject: [labnetwork] Silicon Nitride question In-Reply-To: References: Message-ID: <8F95EA77ACBF904A861E580B44288EFD9B5B26AFA8@FASXCH02.fasmail.priv> Rick, Silicon nitride via LPCVD is an extremely dirty process from the perspective of the vacuum pump. In my experience, I have had the most success with this approach; heat the pumping line from where the transition from quartz to steel is and continue with heat trace up to a liquid cooled trap. This method actually enhances the growth of by-products (mainly ammonium chloride) in an area that can be easily serviced. When I was in manufacturing and we ran these furnaces constantly, this configuration along with a spare water cooled trap, significantly reduced downtime since we controlled where the by-products collected. Here at Harvard we simply use a stainless mesh filter on the pumping line and service the transitional fitting that connects to the quartzware every few months but we don't run nearly as much as a production facility. I am unfamiliar with adding hydrogen to LPCVD nitride, just DCS and NH3. I would choose a pyrolizing type scrubber for any excess SIH4 and if there was added H2 it would mitigate that as well. Regards, Steve Paolini Harvard University CNS From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Morrison, Richard H., Jr. Sent: Wednesday, April 11, 2012 8:09 AM To: labnetwork at mtl.mit.edu Subject: [labnetwork] Silicon Nitride question Hi Everyone, I am restarting a Silicon Nitride LPCVD process and I have a few questions. The process will use a EBARA dry pump therefore should I use a trap on the vacuum pump inlet to catch any particulate generated? Any issue with excess hydrogen from the process going into the dry pump, do I need a burn box on the vacuum pump exhaust? 2nd question has anybody tried to run the LPCVD process on a wafer with a platinum metal pattern on the surface? I was wondering if there maybe some adverse effect because of the catalytic nature of Platinum. Thanks Rick Rick Morrison Senior Member Technical Staff Group Leader Microfabrication Operations Draper Laboratory 555 Technology Square Cambridge, MA 02139 W 617-258-3420 C 508-930-3461 -------------- next part -------------- An HTML attachment was scrubbed... URL: From vincent.luciani at nist.gov Wed Apr 11 12:03:39 2012 From: vincent.luciani at nist.gov (Luciani, Vincent) Date: Wed, 11 Apr 2012 12:03:39 -0400 Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? Message-ID: <01F47D4EDEEC64488C10B767D15E4858100A03CC41@MBCLUSTER.xchange.nist.gov> Hello Mac, If the hood is isolated in a small lab 60 might work, otherwise I would stick with 100. At NIST our safety office uses the 100 CFM number and in my personal experience it seems to be a good number. If you want to go lower than that you need to take in consideration the surrounding area of the hoods and the typical variations in make-up air and exhaust flow. I have found that below 80 CFM fume containment can be compromised by adjacent hoods, hoods directly across (opposing) and fluctuation in static pressure of the cleanroom or lab. We have servo controlled dampers but these fluctuation do happen. 100 CFM seems to hold up against all this noise. Vince NanoFab Manager National Institute of Standards Center for Nanoscale Science and Technology 100 Bureau Drive Gaithersburg, MD 20899 301-975-2886 Sent with Good (www.good.com) -----Original Message----- From: Mac Hathaway [hathaway at cns.fas.harvard.edu] Sent: Wednesday, April 11, 2012 10:10 AM Eastern Standard Time To: labnetwork at mtl.mit.edu Subject: Re: [labnetwork] Face Velocity for Wet benches/Fume hoods? Thanks to all for the helpful replies. At CNS, we are using 100 fpm on our fume hoods and wetbenchs, per ANSI. However, with the push for energy conservation, we're keeping our eyes open. It is interesting to note that the possibility of 60 fpm appears to be bench-specific. Has anyone tested their benches at this flow, successfully or not? Was this in a clean room (with vertical air flow?) Thanks again. Mac Hathaway Harvard Center for Nanoscale Systems On 4/6/2012 10:11 AM, Joe Morgan wrote: Mac, See ANSI/AIHA Z9.5 for laboratory ventilation systems and worker health. In the past 100 feet/per minute has been the golden rule. However, for a number of years now fume hood manufacturers have created new designs that sometimes enable sash velocities as low as 60 feet/minute. The hood must still pass testing and certification as defined by ASHRAE 110. I?m not sure how wet process benches or laminar flow hoods fit into these standards. Best, Joe From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Mac Hathaway Sent: Thursday, April 05, 2012 3:09 PM To: Lab Network (labnetwork at mtl.mit.edu) Subject: [labnetwork] Face Velocity for Wet benches/Fume hoods? Hey all, What do folks currently consider satisfactory regarding the air-flow face velocity at their fume hoods and wet benches? Do you have any ASHRAE/ANSI/SEMI-type standards or references that you draw on for this purpose? The topic came up today in the context of energy savings, lab make-up air, and this sort of thing... Thanks, Mac Hathaway Harvard Center for Nanoscale Systems -------------- next part -------------- An HTML attachment was scrubbed... URL: From bob at eecs.berkeley.edu Thu Apr 12 11:20:57 2012 From: bob at eecs.berkeley.edu (Robert M. Hamilton) Date: Thu, 12 Apr 2012 08:20:57 -0700 Subject: [labnetwork] Silicon Nitride question In-Reply-To: References: Message-ID: <4F86F2D9.4070908@eecs.berkeley.edu> Rick Morrison, The NanoLab (which has superseded the Microlab) at UC Berkeley has a good amount of experience with lpcvd SiN films, both stoiciometric and low-stress. Given our experience I do not recommend using any kind of trap in the pump manifold between the process tube and the pump. Adding a trap to the foreline will concentrate pyrophoric residues. Without frequent cleaning such traps become a significant safety hazard. At best, cleaning a foreline traps is no fun and doing this when the material is pyrophoric is even less fun. We are getting excellent pump lifetime (years) with our Edward iQDP80's without a foreline trap. Heat tracing is a common recommendation for the pump lines of lpcvd nitride furnaces. We purposefully do not heat our foreline. We've found running an unheated foreline has advantageous. Forelines condense and trap effluent. A heated foreline results in the volatilization of trapped effluents (DCS, i.e. H2SiCl2 and it fractions) which will back-stream into the process tube and "cvd" particles onto substrates during loading. While we do not heat our manifold we do use a "Tystar Corp-modified", heated HPS "Jalapeno series" valve (200 C). This valve is unique. The Tystar Corp valve modification allows for continuous pumping of a small volume of gas while wafers are loaded preventing back-diffusion of effluent from the pump manifold. It also has a self-cleaning flow orifice. It is a significant improvement for SiN particle management. I recommend you contact Henry Heidbreder for more information, henryh at tystar.com As for how to deal with process-created H2, the Ebara, Edwards and other dry pumps use considerable N2 purge during operation, typically ~35 slpm. These pumps provide an interlock via their interface module which can be used to disable DCS flow in the event of low N2 flows. Purge N2 will reduce the H2 concentration well below the ~4% lower flammable limit (LFL) for H2 in air. It is good practice to "marry" a pumps exhaust connection to a main duct in a high-flow area of the exhaust duct further reducing concentrations well below the flammable limits. (I have seen the LFL sometimes listed as the LEL (lower explosive limit); however, the LEL for H2 in air is higher than the LFL, ~17%). I defer to others with more process knowledge about issues with Pt and nitride deposition. Bob Hamilton Robert M. Hamilton Marvel NanoLab University of CA at Berkeley Rm 520 Sutardja Dai Hall Berkeley, CA 94720-1754 bob at eecs.berkeley.edu (e-mail preferred) 510-809-8600 510-325-7557 (Emergencies) On 4/11/2012 5:08 AM, Morrison, Richard H., Jr. wrote: > > Hi Everyone, > > I am restarting a Silicon Nitride LPCVD process and I have > a few questions. The process will use a EBARA dry pump > therefore should I use a trap on the vacuum pump inlet to > catch any particulate generated? > > Any issue with excess hydrogen from the process going into > the dry pump, do I need a burn box on the vacuum pump exhaust? > > 2^nd question has anybody tried to run the LPCVD process > on a wafer with a platinum metal pattern on the surface? I > was wondering if there maybe some adverse effect because > of the catalytic nature of Platinum. > > Thanks > > Rick > > Rick Morrison > > Senior Member Technical Staff > > Group Leader Microfabrication Operations > > Draper Laboratory > > 555 Technology Square > > Cambridge, MA 02139 > > W 617-258-3420 > > C 508-930-3461 > > > > _______________________________________________ > labnetwork mailing list > labnetwork at mtl.mit.edu > https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork -------------- next part -------------- An HTML attachment was scrubbed... URL: From shott at stanford.edu Thu Apr 12 12:00:17 2012 From: shott at stanford.edu (John Shott) Date: Thu, 12 Apr 2012 09:00:17 -0700 Subject: [labnetwork] Silicon Nitride question In-Reply-To: References: Message-ID: <4F86FC11.2010409@stanford.edu> Rick: To add our practices at Stanford to the discussion ... 1. Our newer, higher quality system has heated line between tube and pump as well as an inline mesh filter before the pump. 2. Our older system actually only has a filter on the exhaust side of the pump. That is primarily to help avoid buildup in the exhaust line. Our exhaust line is actually too small ... 1" OD ... so occlusion of the exhaust line can be a problem. We have some form of abatement on each system .... in fact all of our LPCVD either runs to an old Innovative Engineering/Delatech CDO unit running at 800 C or to a Pure Air EDOC (Dynamic Oxidation Chamber) to treat exhaust gases. The output of either the CDO or EDOC then goes to our building-wide water scrubber .... that will remove the HCl and ammonia products from the nitride process. Note: I believe that just about all nitride LPCVD processes will have significant fractions of unreacted DCS coming out the end of the tube. That is particularly true if you are running hgh DCS flows, which is often the case if you are trying to produce a silicon-rich, low-stress nitride film. So, even though we don't use production volumes of gas, we still believe in abatement on all LPCVD tubes. Good luck, John On 4/11/2012 5:08 AM, Morrison, Richard H., Jr. wrote: > > Hi Everyone, > > I am restarting a Silicon Nitride LPCVD process and I have a few > questions. The process will use a EBARA dry pump therefore should I > use a trap on the vacuum pump inlet to catch any particulate generated? > > Any issue with excess hydrogen from the process going into the dry > pump, do I need a burn box on the vacuum pump exhaust? > > 2^nd question has anybody tried to run the LPCVD process on a wafer > with a platinum metal pattern on the surface? I was wondering if there > maybe some adverse effect because of the catalytic nature of Platinum. > > Thanks > > Rick > -------------- next part -------------- An HTML attachment was scrubbed... URL: From pi12 at cornell.edu Thu Apr 12 16:54:40 2012 From: pi12 at cornell.edu (Philip Infante) Date: Thu, 12 Apr 2012 20:54:40 +0000 Subject: [labnetwork] Silicon Nitride question In-Reply-To: References: Message-ID: Hello Rick, At the CNF we run a heated valve and fore line from the quartz tube up to an MKS/HPS water cooled trap. The trap condenses out the ammonium chloride byproduct from the process and is easily cleaned with water on a periodic maintenance interval. We also use HPS jacketed heaters self regulated at 150 C. This set up works great and we get minimal deposit between the trap and dry pump. We use an Ebara dry pump running at a 125 C case temp and heat the pump outlet line up to an Edwards Gas Reactor Column before it hits the pump exhaust main. The majority of the work here is silicon rich/low stress nitride - which uses higher dichlorosilane flows. Unreacted dichlorosilane is a bigger concern than the hydrogen byproduct. Scrubbing the pump outlet is important and we have learned from "real world experience" that even at very low dilutions (<1% SICl2H2) you can get a flammable/explosive deposits built up in the pump exhaust over time. I have attached a paper that describes this deposit build up associated with dichlorosilane based processes. Since installing the scrubber we have not had any issues with deposits building up. I am not sure of what effect the platinum would have with the process gas. Phil Phil Infante Cornell NanoScale Facility Cornell University 250 Duffield Hall Ithaca, NY 14853 607-254-4926 On Apr 11, 2012, at 8:08 AM, Morrison, Richard H., Jr. wrote: Hi Everyone, I am restarting a Silicon Nitride LPCVD process and I have a few questions. The process will use a EBARA dry pump therefore should I use a trap on the vacuum pump inlet to catch any particulate generated? Any issue with excess hydrogen from the process going into the dry pump, do I need a burn box on the vacuum pump exhaust? 2nd question has anybody tried to run the LPCVD process on a wafer with a platinum metal pattern on the surface? I was wondering if there maybe some adverse effect because of the catalytic nature of Platinum. Thanks Rick Rick Morrison Senior Member Technical Staff Group Leader Microfabrication Operations Draper Laboratory 555 Technology Square Cambridge, MA 02139 W 617-258-3420 C 508-930-3461 _______________________________________________ labnetwork mailing list labnetwork at mtl.mit.edu https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: nitrideexhaustdeposits.pdf Type: application/pdf Size: 107868 bytes Desc: nitrideexhaustdeposits.pdf URL: From daniel.woodie at cornell.edu Thu Apr 12 17:41:06 2012 From: daniel.woodie at cornell.edu (Dan Woodie) Date: Thu, 12 Apr 2012 21:41:06 +0000 Subject: [labnetwork] FW: Silicon Nitride question In-Reply-To: References: Message-ID: <1A2C639447BEA24EA19C3A3B7DF59AF90952602F@MBXD-01.exchange.cornell.edu> Richard, At the Cornell NanoScale Facility, we use the foreline cold trap method to pull out most of the deposits that would build up in the foreline areas. We have seen that the flammable deposits that can occur have mostly been in areas where you can get partial reactivity of the silanes, such as low oxygen environments like vacuum pump exhaust lines post pump, where the high pump nitrogen purge leads to a low oxygen area. We had a problem here with these deposits and so we added Edwards Gas Reactor Columns (GRC) units immediately after the pump. Attached is a paper we found describing what occurs. The deposits we get in the cold trap have been mostly ammonium chloride which remove easily in warm water. Dan Daniel Woodie Safety Manager, College of Engineering Cornell University 344 Duffield Hall Ithaca, NY 14853-2700 (607)254-4891 Off Hour Emergency # - (607)227-2993 From: labnetwork-bounces at mtl.mit.edu [mailto:labnetwork-bounces at mtl.mit.edu] On Behalf Of Morrison, Richard H., Jr. Sent: Wednesday, April 11, 2012 8:09 AM To: labnetwork at mtl.mit.edu Subject: [labnetwork] Silicon Nitride question Hi Everyone, I am restarting a Silicon Nitride LPCVD process and I have a few questions. The process will use a EBARA dry pump therefore should I use a trap on the vacuum pump inlet to catch any particulate generated? Any issue with excess hydrogen from the process going into the dry pump, do I need a burn box on the vacuum pump exhaust? 2nd question has anybody tried to run the LPCVD process on a wafer with a platinum metal pattern on the surface? I was wondering if there maybe some adverse effect because of the catalytic nature of Platinum. Thanks Rick Rick Morrison Senior Member Technical Staff Group Leader Microfabrication Operations Draper Laboratory 555 Technology Square Cambridge, MA 02139 W 617-258-3420 C 508-930-3461 -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: nitrideexhaustdeposits.pdf Type: application/pdf Size: 107868 bytes Desc: nitrideexhaustdeposits.pdf URL: From joseph_ring at harvard.edu Fri Apr 13 15:16:53 2012 From: joseph_ring at harvard.edu (Ring, Joseph P.) Date: Fri, 13 Apr 2012 19:16:53 +0000 Subject: [labnetwork] Health and Safety Office Opening at Harvard Message-ID: <6DB8E2434A4A5B409F02979B5DCE5CBC0FDC3E8B@ENTWEXMB0000006.university.harvard.edu> Harvard University has an exciting opportunity for an experienced Materials Safety Officer. Working collaboratively with a close knit team, the incumbent will consult with a diverse array of faculty, researcher staff and other safety professionals to deliver the resources needed to advance our leadership in materials, microelectronic and nanotechnology research. The successful candidate will be responsible for the implementation and management of the laboratory safety, industrial hygiene, Clean Air Act, hazardous waste and toxic gas programs in the nanotechnology research areas. We seek an individual with a Bachelor of Science in environmental health and safety related discipline; preferably industrial hygiene, engineering or equivalent; A Master of Science is preferred. A minimum of five years experience working with environmental health and safety programs, hazardous gas, and clean room laboratory experience preferred. Require strong working knowledge of regulations, with primary emphasis on OSHA laboratory compliance. Prefer knowledge of NFPA, CDC, and DEP/EPA regulations. Must have excellent communications skills, operational level expertise to implement EHSEM programs; demonstrated ability to work independently, cooperatively and collaboratively and with a proven philosophy of service. Interested individuals are asked to review the complete position description, and apply on-line at, http://employment.harvard.edu for position 26311BR. Please contact Tori_Caldwell at harvard.edu , if you have any questions. -------------- next part -------------- An HTML attachment was scrubbed... URL: From cab24 at sfu.ca Fri Apr 13 19:47:21 2012 From: cab24 at sfu.ca (Chris Balicki) Date: Fri, 13 Apr 2012 16:47:21 -0700 (PDT) Subject: [labnetwork] Silicon Nitride question In-Reply-To: Message-ID: <830568450.25768334.1334360841556.JavaMail.root@jaguar9.sfu.ca> Hello Everyone, Here at Simon Fraser University, we are also optimizing our SiN LPCVD setup. Certainly, we appreciate the recent responses and recommendations. The dry pump (Edward iQDP80 in our case) requires significant N2 purge flow. Currently, we supply this N2 via a membrane generator. Since the generator capacity has been taxed, current O2 levels are between 1.5-2.0%. Our pump exhaust is fed to an Edwards TPU via a ~15ft run of unheated SS tubing. 1. Are O2 levels of 1.5-2.0% harmful to dry pump operation? If so, what N2 purity is recommended? 2. What further measures are recommended to minimize pump exhaust buildup due to O2 content and unreacted silanes/byproducts? Thanks, Chris --- Christopher Balicki Clean Room Technician, EIT 4D LABS, Simon Fraser University 8888 University Drive Burnaby, BC V5A 1S6 t: 778-782-8026 e: balicki at 4dlabs.ca w: www.4dlabs.ca ----- Original Message ----- From: "Richard H. Morrison, Jr." To: labnetwork at mtl.mit.edu Sent: Wednesday, April 11, 2012 5:08:56 AM Subject: [labnetwork] Silicon Nitride question Hi Everyone, I am restarting a Silicon Nitride LPCVD process and I have a few questions. The process will use a EBARA dry pump therefore should I use a trap on the vacuum pump inlet to catch any particulate generated? Any issue with excess hydrogen from the process going into the dry pump, do I need a burn box on the vacuum pump exhaust? 2 nd question has anybody tried to run the LPCVD process on a wafer with a platinum metal pattern on the surface? I was wondering if there maybe some adverse effect because of the catalytic nature of Platinum. Thanks Rick Rick Morrison Senior Member Technical Staff Group Leader Microfabrication Operations Draper Laboratory 555 Technology Square Cambridge, MA 02139 W 617-258-3420 C 508-930-3461 _______________________________________________ labnetwork mailing list labnetwork at mtl.mit.edu https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork From bob at eecs.berkeley.edu Mon Apr 16 12:47:19 2012 From: bob at eecs.berkeley.edu (Robert M. Hamilton) Date: Mon, 16 Apr 2012 09:47:19 -0700 Subject: [labnetwork] Silicon Nitride question In-Reply-To: <830568450.25768334.1334360841556.JavaMail.root@jaguar9.sfu.ca> References: <830568450.25768334.1334360841556.JavaMail.root@jaguar9.sfu.ca> Message-ID: <4F8C4D17.1070008@eecs.berkeley.edu> Chris Balicki, Re: less than ideal N2 pump purge gas purity/lpcvd nitride pumps: I have found my conversations with Edwards constructive and their pump staff well informed. My first suggestion is to call Edwards for some guidance on the issue of your N2 quality, the partial pressures of O2 and its affects on their pumps. The iQ series pump have been our stalwarts for decades. We continue to have them rebuilt as needed. For the nitride process we see lifetimes of three years and better. We operate our nitride with iQ's and Edwards QMB blowers. Appended is an excerpt from the Q-series instruction manual which offers insight into the N2 purge circuits. I am attaching the pdf to this reply; however, it may not be deliverable to the rest of the labnetwork list e-mails because of IT security. 4.2 Gas flow rates and pressures Table 2 (see Section 2) shows the maximum flow rates for the shaft-seals purge, 3/4-interstage purge and 2/3-interstage purge gas flows. During operation, you must set the flow rates of the 3/4-interstage purge and the 2/3-interstage purge pipelines to the required values. These values are dependent on the process in which the pump is used and you should adjust the flow rates according to your experience. If you exceed the flow rates specified in Table 2, the performance of the pump may be reduced. You must set the pressure of the shaft-seals purge as specified in Table 2 and Section 3.11. You must not attempt to adjust the flow rate of the shaft-seals purge (which is determined by the pumpitself). The nominal flow rate of the shaft-seals purge is 12 l.min-1 . If the flow rate is higher than the nominal value, you may reduce the flow rate of the 3/4-interstage purge by [F-12] l.min-1 (where F is the actual shaft-seals flow rate). This will reduce the amount of nitrogen exhausted from the pump. As you can see, the purge gas on an iQ series pump goes to several locations, the gear box to protect the transmission and seals, two interstage areas and the exhaust. I would guess the interstage will be the area of most concern given your O2 partial pressure as this is where most of the reaction products are likely to form. Part of the purpose of this interstage purge is to prevent a phase change to a liquid of the pumped gases, during compression. Given the nitride process you may be able to operate by completely shutting off the interstage N2 purge (for safety, the exhaust gas purge should remain in spec. as this is part of dilution). Call Edwards tech support. They can offer you better guidance. Note, our lpcvd nitride tubes deliver a variety of nitride films and are also used for HTO (high temperature oxide). The Pareto numbers for the two tubes, (one restricted to MOS and one for MEMS) are, for the last 12 months: MOS: 86.94% availability MEMS: 85.50% " Prior to H2O our uptimes were in the mid 90%. I expect to improve our current numbers with modifications to the way we add N2O for the HTO process and the way we manage our N2O recipes. I'd be interested in learning your results. Liquid nitrogen/N2 is one of our largest operating costs. We've toyed with on-sight N2 generation; however, installation is a "big bite" and a plant not without operating costs. So far we've passed this up given the purities such on-site generation delivers. Bob Hamilton Robert M. Hamilton Marvel NanoLab University of CA at Berkeley Rm 520 Sutardja Dai Hall Berkeley, CA 94720-1754 bob at eecs.berkeley.edu (e-mail preferred) 510-809-8600 510-325-7557 (Emergencies) On 4/13/2012 4:47 PM, Chris Balicki wrote: > Hello Everyone, > > Here at Simon Fraser University, we are also optimizing our SiN LPCVD setup. Certainly, we appreciate the recent responses and recommendations. > > The dry pump (Edward iQDP80 in our case) requires significant N2 purge flow. Currently, we supply this N2 via a membrane generator. Since the generator capacity has been taxed, current O2 levels are between 1.5-2.0%. Our pump exhaust is fed to an Edwards TPU via a ~15ft run of unheated SS tubing. > > 1. Are O2 levels of 1.5-2.0% harmful to dry pump operation? If so, what N2 purity is recommended? > 2. What further measures are recommended to minimize pump exhaust buildup due to O2 content and unreacted silanes/byproducts? > > Thanks, > > Chris > > --- > Christopher Balicki > Clean Room Technician, EIT > 4D LABS, Simon Fraser University > 8888 University Drive > Burnaby, BC V5A 1S6 > t: 778-782-8026 e: balicki at 4dlabs.ca w: www.4dlabs.ca > > ----- Original Message ----- > From: "Richard H. Morrison, Jr." > To: labnetwork at mtl.mit.edu > Sent: Wednesday, April 11, 2012 5:08:56 AM > Subject: [labnetwork] Silicon Nitride question > > > > > > Hi Everyone, > > > > I am restarting a Silicon Nitride LPCVD process and I have a few questions. The process will use a EBARA dry pump therefore should I use a trap on the vacuum pump inlet to catch any particulate generated? > > > > Any issue with excess hydrogen from the process going into the dry pump, do I need a burn box on the vacuum pump exhaust? > > > > 2 nd question has anybody tried to run the LPCVD process on a wafer with a platinum metal pattern on the surface? I was wondering if there maybe some adverse effect because of the catalytic nature of Platinum. > > > > Thanks > > Rick > > > > > > Rick Morrison > > Senior Member Technical Staff > > Group Leader Microfabrication Operations > > Draper Laboratory > > 555 Technology Square > > Cambridge, MA 02139 > > > > W 617-258-3420 > > C 508-930-3461 > > > _______________________________________________ > labnetwork mailing list > labnetwork at mtl.mit.edu > https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork > > _______________________________________________ > labnetwork mailing list > labnetwork at mtl.mit.edu > https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork -------------- next part -------------- A non-text attachment was scrubbed... Name: QDP 40 80 manual.pdf Type: application/pdf Size: 1935506 bytes Desc: not available URL: From diadiuk at MIT.EDU Fri Apr 20 11:08:50 2012 From: diadiuk at MIT.EDU (Vicky Diadiuk) Date: Fri, 20 Apr 2012 11:08:50 -0400 Subject: [labnetwork] MIT will host OpenCoral.org Message-ID: Dear colleagues, Recently Stanford informed us that OpenCoral.org will remain an active site for the discussion, development, and distribution of OpenCoral. However, Stanford will not be able to continue to host the website, since they do not plan to run Coral after they transition to Badger (the new commercial version of CORAL). Since MIT will continue to use and maintain CORAL, we agreed to host the forum and the web content. In contrast to Stanford, however, we don't have the resources necessary to provide the extensive help that John Shott has offered in the past. We will rely on the expertise of all CORAL users to help each other. After the transition to MIT, we do not expect to do as much development and functionality additions as Bill Murray had been able to do, but we will keep CORAL current, i.e. compatible with modern operating systems and databases. Our intent is to continue the collaboration between the user-institutions in assisting each other with maintenance of the systems we are already using. With John Shott?s help we are presently working to make a smooth transition of OpenCoral.org hosting from Stanford to MIT. Please let us know if you have any questions and/or if you would like to assist with the transition and future CORAL maintenance. Vicky (on behalf of the MIT CORAL Team) From matthieu.nannini at mcgill.ca Wed Apr 25 17:42:05 2012 From: matthieu.nannini at mcgill.ca (Matthieu Nannini, Dr.) Date: Wed, 25 Apr 2012 21:42:05 +0000 Subject: [labnetwork] Low temperature LPCVD Silicon Message-ID: Dear colleagues, A researcher in the lab would like to run our poly tube as low as 400?C. He is using very dilute amounts of Silane in N2. At this temperature, I have concerns about unreacted silane in the pump. Our Ebara dry pumps are purged with filtered (2% O2) air and we never had any issue with them. Does anyone have experience running a poly tube that low ? Thanks Matthieu Nannini McGill Nanotools Microfab mnm.physics.mcgill.ca