From mcvittie at snf.stanford.edu Mon Nov 3 13:56:16 2003 From: mcvittie at snf.stanford.edu (Jim McVittie) Date: Mon, 03 Nov 2003 13:56:16 -0800 Subject: Poll on Use of PQuest at 200C Message-ID: <3FA6CF00.C64CBFF4@snf.stanford.edu> PQuest Users, I have 2 users, who would like to treat their samples in a H2 plasma at temperatures between 200 and 250C. The PQuest should be able to do this since it was designed to do PECVD as well as etching in that it has a heater in the wafer check. Right now we have no written procedures for going above 90C and there is a question about how high of a temperature the Vespel wafer lift pins can take. As for the Vespel pins, I am still checking to see which type of Vespel was used for making them. The mechanical properities for the lowest grade Vespel are good to 280C. If the all currents materials in the system will allow going to 200 or 250C, what is your opinion of allowing these users to use the PQuest in this mode? Right now I do not believe their will be a problem but we have not used the chuck heater for a number of years. Thanks, Jim -------------- next part -------------- A non-text attachment was scrubbed... Name: mcvittie.vcf Type: text/x-vcard Size: 422 bytes Desc: Card for Jim McVittie URL: From true at snf.stanford.edu Mon Nov 3 14:38:50 2003 From: true at snf.stanford.edu (Randall True) Date: Mon, 3 Nov 2003 14:38:50 -0800 (PST) Subject: Poll on Use of PQuest at 200C In-Reply-To: <3FA6CF00.C64CBFF4@snf.stanford.edu> Message-ID: Jim, I do not think that a new high temperature H2 process should be approved on the PQuest. As you know very well, we have had many problems with the Pquest in the recent past, both with availibility and compatibility of processes. The is why you adopted a policy of no new processes on the system. Since you established that policy and decided to split the week between GaAs and Non-GaAs, no further experiments have been done to investigate what the root cause of the processing problems were. Moreover, you never provided the compiled list of approved Non-GaAs processes as promised. Given that procedures for introducing new Non-GaAs processes, or even evaluating currently used ones, have not been put in place, I don't think it is appropriate to approve this new high-temp H2 process. This would be inconsistent with your policy changes in June. I also have concerns about running the system at 200C. If something goes wrong, the system could be down for a considerable amount of time. I think another, non-high performance etcher, like drytek4 or MRC should be used instead. I, my company, and many other users are counting on the PQuest being operational and consistent, and we cannot afford for it to go down yet again. --Randy On Mon, 3 Nov 2003, Jim McVittie wrote: > PQuest Users, > > I have 2 users, who would like to treat their samples in a H2 plasma at > temperatures between 200 and 250C. The PQuest should be able to do this > since it was designed to do PECVD as well as etching in that it has a > heater in the wafer check. Right now we have no written procedures for > going above 90C and there is a question about how high of a temperature > the Vespel wafer lift pins can take. As for the Vespel pins, I am still > checking to see which type of Vespel was used for making them. The > mechanical properities for the lowest grade Vespel are good to 280C. > > If the all currents materials in the system will allow going to 200 or > 250C, what is your opinion of allowing these users to use the PQuest in > this mode? Right now I do not believe their will be a problem but we > have not used the chuck heater for a number of years. > > Thanks, Jim > From mcvittie at snf.stanford.edu Wed Nov 5 12:15:23 2003 From: mcvittie at snf.stanford.edu (Jim McVittie) Date: Wed, 05 Nov 2003 12:15:23 -0800 Subject: Poll on Use of PQuest at 200C References: <1068017248.3fa8a66083364@webmail.stanford.edu> Message-ID: <3FA95A5B.B3F4FE96@snf.stanford.edu> Hui, See reply below. > Jim, > > I know essentially nothing about that H2 treatment, so it is hard to vote > yes or no. But I have a few concerns. Firstly, can the rubber ring sustain > such high temperature? > To go above 100C the chuck o-ring has to be removed. With this o-ring removed, no rubber /polymer parts should get hot when the chuck is heated above 100C. The processes to worry about in regard to the o-ring are those using high percentages oxygen, such used for chamber cleaning and etch polymers. > > Is there a cleaning/seasoning recipe required after/before the high-T H2 > procedure? And will it make a serious damage or contamination to the > system if a wrong wafer is put in for that H2 procedure? > As with any significant process changes in a plasma system, the chamber needs seasoning before starting a new process. This is true for all process changes. If your processs is different than that used by the previous user, the general rule is to start by seasoning the chamber using the new process and a few dummy wafers. > > If the system is able to handle the procedure, are there special steps to > take before and after the H2 plasma procedure, or, will the procedure be > much trickier than the standard one, so that users might be more > vulnerable to mistakes? > > At this time, I do not see that a H2 process will cause any special problems other than the expected thermal stress on the chuck and the connections to it. There would be additional procedures needed before and after heating the chuck above 100C. As mentioned above the chuck o-ring would have to removed and replaced afterwards. In addition, we would probably want to blow out the chuck cooling line with N2 before heating the chuck. Jim > Hui > > Quoting Jim McVittie : > > > PQuest Users, > > > > I have 2 users, who would like to treat their samples in a H2 plasma at > > temperatures between 200 and 250C. The PQuest should be able to do this > > since it was designed to do PECVD as well as etching in that it has a > > heater in the wafer check. Right now we have no written procedures for > > going above 90C and there is a question about how high of a temperature > > the Vespel wafer lift pins can take. As for the Vespel pins, I am still > > checking to see which type of Vespel was used for making them. The > > mechanical properities for the lowest grade Vespel are good to 280C. > > > > If the all currents materials in the system will allow going to 200 or > > 250C, what is your opinion of allowing these users to use the PQuest in > > this mode? Right now I do not believe their will be a problem but we > > have not used the chuck heater for a number of years. > > > > Thanks, Jim > > -------------- next part -------------- A non-text attachment was scrubbed... Name: mcvittie.vcf Type: text/x-vcard Size: 422 bytes Desc: Card for Jim McVittie URL: From mcvittie at snf.stanford.edu Wed Nov 5 13:07:10 2003 From: mcvittie at snf.stanford.edu (Jim McVittie) Date: Wed, 05 Nov 2003 13:07:10 -0800 Subject: Poll on Use of PQuest at 200C References: <3FA6CF00.C64CBFF4@snf.stanford.edu> <000501c3a3c3$6c9d3c60$6401a8c0@Stanford.EDU> Message-ID: <3FA9667E.86EFA4F9@snf.stanford.edu> Mike, When the PQuest was first installed, the wafer chuck was heated above 100C a number of times to do silicon nitride depositions with no problems caused by the temperature. The main problem from the deposition runs was by-products on the chamber walls. I am sorry that I do not have the details on the specific temperatures used. A while back, I loaned my PQuest process file out and never got it back. The PQuest report that I have for nitride dep says that the deposition temperatures ranges are from 100 to 300C. In addition, I recall that the system was used at least once for a high temperature H2 plasma anneal. I will contact the former student, who did this anneal, to see if he recalls what temperature was used. Let me point out a couple facts about the tool. At the time of its purchase, InP etching was the main reason why the heated chuck specified. Plasmaquest specified that InP etching needs at least 150C. The chuck temperature range in the PQuest specifications is -150C to +350C. If the chuck was designed to go to 350C, I can not see why it should be a problem to go to 200C. While I understand why you are afraid to rock the boat and want to avoid anything that might slow down your thesis work, I really hate to loss the heated chuck capability of this tool. We have no other etcher in the lab with this capability and we have InP users who could really use this capability. Jim Michael Wiemer wrote: > I am nervous about these high temps. It seems risky to make such a large > change. > > We rely on the PQuest too and these high temps, even if they dont mess up > other processes, may result in something being broken. Since the PQuest is > not supported anymore by its parent company, when the PQuest goes down, > there is always a risk that the problem is major and cant be fixed in a > reasonable amount of time. It seems like a bad machine to start altering. > > My 2 cents. :) > > -Mike > > ----- Original Message ----- > From: "Jim McVittie" > To: > Sent: Monday, November 03, 2003 1:56 PM > Subject: Poll on Use of PQuest at 200C > > > PQuest Users, > > > > I have 2 users, who would like to treat their samples in a H2 plasma at > > temperatures between 200 and 250C. The PQuest should be able to do this > > since it was designed to do PECVD as well as etching in that it has a > > heater in the wafer check. Right now we have no written procedures for > > going above 90C and there is a question about how high of a temperature > > the Vespel wafer lift pins can take. As for the Vespel pins, I am still > > checking to see which type of Vespel was used for making them. The > > mechanical properities for the lowest grade Vespel are good to 280C. > > > > If the all currents materials in the system will allow going to 200 or > > 250C, what is your opinion of allowing these users to use the PQuest in > > this mode? Right now I do not believe their will be a problem but we > > have not used the chuck heater for a number of years. > > > > Thanks, Jim > > -------------- next part -------------- A non-text attachment was scrubbed... Name: mcvittie.vcf Type: text/x-vcard Size: 422 bytes Desc: Card for Jim McVittie URL: From mcvittie at snf.stanford.edu Wed Nov 5 15:09:59 2003 From: mcvittie at snf.stanford.edu (Jim McVittie) Date: Wed, 05 Nov 2003 15:09:59 -0800 Subject: Poll on Use of PQuest at 200C References: Message-ID: <3FA98347.8BBF1982@snf.stanford.edu> All, It is clear I have few supporters for trying out the PQuest at temperatures above 100C. I will wait a year and see if I get the same reaction next year. Jim Luigi Scaccabarozzi wrote: > Jim, > there is something not clear to me about the o-ring : you are saying that > every time the chuck goes above 100C > we have to remove and put back in place/change the o-ring? > Would that mean opening the chamber evry time these users run their > process? > I hope I misunderstood you, otherwise I don't see why the tool has a > rubber o-ring AND is supposed to run high tmep processes... > Thanks > Gigi > > On Wed, 5 Nov 2003, Jim McVittie wrote: > > > Hui, > > > > See reply below. > > > > > Jim, > > > > > > I know essentially nothing about that H2 treatment, so it is hard to vote > > > yes or no. But I have a few concerns. Firstly, can the rubber ring sustain > > > such high temperature? > > > > > > > To go above 100C the chuck o-ring has to be removed. With this o-ring removed, > > no rubber > > /polymer parts should get hot when the chuck is heated above 100C. The > > processes to worry about in regard to the o-ring are those using high > > percentages oxygen, such used for chamber cleaning and etch polymers. > > > > > > > > Is there a cleaning/seasoning recipe required after/before the high-T H2 > > > procedure? And will it make a serious damage or contamination to the > > > system if a wrong wafer is put in for that H2 procedure? > > > > > > > As with any significant process changes in a plasma system, the chamber needs > > seasoning before starting a new process. This is true for all process changes. > > If your processs is different than that used by the previous user, the general > > rule is to start by seasoning the chamber using the new process and a few > > dummy wafers. > > > > > > > > If the system is able to handle the procedure, are there special steps to > > > take before and after the H2 plasma procedure, or, will the procedure be > > > much trickier than the standard one, so that users might be more > > > vulnerable to mistakes? > > > > > > > > > > At this time, I do not see that a H2 process will cause any special problems > > other than the expected thermal stress on the chuck and the connections to it. > > There would be additional procedures needed before and after heating the chuck > > above 100C. As mentioned above the chuck o-ring would have to removed and > > replaced afterwards. In addition, we would probably want to blow out the chuck > > cooling line with N2 before heating the chuck. > > > > Jim > > > > > Hui > > > > > > Quoting Jim McVittie : > > > > > > > PQuest Users, > > > > > > > > I have 2 users, who would like to treat their samples in a H2 plasma at > > > > temperatures between 200 and 250C. The PQuest should be able to do this > > > > since it was designed to do PECVD as well as etching in that it has a > > > > heater in the wafer check. Right now we have no written procedures for > > > > going above 90C and there is a question about how high of a temperature > > > > the Vespel wafer lift pins can take. As for the Vespel pins, I am still > > > > checking to see which type of Vespel was used for making them. The > > > > mechanical properities for the lowest grade Vespel are good to 280C. > > > > > > > > If the all currents materials in the system will allow going to 200 or > > > > 250C, what is your opinion of allowing these users to use the PQuest in > > > > this mode? Right now I do not believe their will be a problem but we > > > > have not used the chuck heater for a number of years. > > > > > > > > Thanks, Jim > > > > > > -------------- next part -------------- A non-text attachment was scrubbed... Name: mcvittie.vcf Type: text/x-vcard Size: 422 bytes Desc: Card for Jim McVittie URL: From wistey at snowmass.Stanford.EDU Wed Nov 5 23:43:40 2003 From: wistey at snowmass.Stanford.EDU (Mark Wistey) Date: Wed, 5 Nov 2003 23:43:40 -0800 (PST) Subject: Poll on Use of PQuest at 200C In-Reply-To: <3FA6CF00.C64CBFF4@snf.stanford.edu> Message-ID: On Mon, 3 Nov 2003, Jim McVittie wrote: > I have 2 users, who would like to treat their samples in a H2 plasma at > temperatures between 200 and 250C. The PQuest should be able to do this > since it was designed to do PECVD as well as etching in that it has a > heater in the wafer check. I have to admit this makes me quite nervous, although I don't know the internal details of the PQuest enough to know whether my fears are grounded or not. PECVD and hydrogen plasmas are very different in how they attack metals; temperature is not the only thing to worry about. I know of one MBE system which had all of its cells completely destroyed (to the tune of $100-200k) because of hydrogen embrittlement due to the hydrogen plasma source. It seems a terrible gamble to take with such a nice piece of equipment--which several of us depend on for our research. - Mark From scaccag at stanford.edu Wed Nov 12 21:18:52 2003 From: scaccag at stanford.edu (Luigi Scaccabarozzi) Date: Wed, 12 Nov 2003 21:18:52 -0800 (PST) Subject: pquest free tomorrow morning Message-ID: From mtopinka at stanford.edu Fri Nov 14 04:11:41 2003 From: mtopinka at stanford.edu (Mark Topinka) Date: Fri, 14 Nov 2003 04:11:41 -0800 Subject: etching InAs / InAlAs / AlSb / GaSb Message-ID: <5.2.0.9.0.20031114040753.0363b038@mtopinka.pobox.stanford.edu> If anybody has any experience, good references, or ideas about etching any or all the materials in the subject line (which are: InAs, InAlAs, AlSb, and GaSb) I would really appreciate hearing your advice! Thanks very much. Sincerely -Mark Topinka PS- I so have one recipe which uses Argon, Hydrogen, and Methane. I'm interested in trying it, but it is rather slow at etching AlSb (2nm/minute) which makes me a bit worried about my mask material (either PMMA or chrome, or possibly other material?)