Episode 31 features German ALD professor, Dr. Martin Knaut. Martin is the chair for the Institute of Semiconductor and Microsystems Technology at TU Dresden and the atomic layer processing group leader. He is also a founding member of the Atomic Layer Process Innovation Network, or ALPIN, organizer of the annual ALD for Industry event, and runs a small in situ tool development company, called ALS Metrology. With a long career working with ALD in Dresden, at the likes of Infineon and Qimonda, Martin has witnessed the ebbs and flows of the semiconductor industry in the state of Saxony.
Martin and Tyler discuss the goal of the Silicon Saxony organization, how we can better recruit students in microelectronics, and why he originally started the Atomic Layer Process Innovation Network. They also discuss his company, ALS Metrology, the importance of using in situ monitoring for process development, and his work on flash-enhanced ALD.
In this episode:
00:00 Intro
01:48 Martin’s background & semiconductors in Dresden
10:00 Recruiting issues for microelectronics
17:29 ALPIN & ALD for Industry events
29:34 ALS Metrology
34:57 Importance of in situ monitoring
41:59 Flash-Enhanced ALD
53:55 Concluding remarks
Welcome to Al stories a series chronicling the personal journeys of the people behind Atomic air deposition Untold Stories of the technology and deep dives into the history development and future of Al I’m your host Tyler Myers bringing you this podcast from benic the home of Al welcome back to a
New year of Al stories we start off 2024 with a well-known face in the German Al Community Professor Martin not Martin is professor and chair for the Institute of semiconductor and Microsystems technology at tu pres and the atomic layer processing group leader he’s also a founding member of the atomic layer
Process Innovation Network or Alpine organizer of the annual Al for industry event and runs a small Institute tool development company called ALS Metrology with a long career working with Al and dresen at the legs of infin and Kuma Martin has witnessed the es and flows of the semiconductor industry in the state of
Saxony in this episode Martin and I discuss the goal of the Silicon Saxy organization how we can better recruit students in microelectronics and why he originally started the atomic layer process Innovation Network we also discuss his company ALS Metrology the importance of using Institute monitoring for process development and his work on
Flash enhanced Al Martin and I had a really wonderful conversation ranging the full spectrum of topics available when discussing Al it was a pleasure to have them join a stories and I extend a huge thanks for his time and willingness to contribute so soon after meeting me
So with that please grab your tea or coffee and enjoy te dress in Martin note good well hey Martin thank you for joining and welcome to the the a stor podcast it’s really nice to have you here and I’m excited to to discuss some
Of the work that you do at T Dresden and just talk about Dres in in general so yeah welcome welome to the show thanks and I’m also enjoy being here so looking forward let’s see good good so as is tradition on this show we usually just start talking about your background a
Little bits and how you found yourself working in Al yeah what kind of Drew you to it and what what kept you there so so yeah if you could go ahead and give us a little bit of an idea how you found yourself in this field yeah so I started
With my studies in electrical engineering in 2000 and because I wanted to do something which was related to engineering and then I decided oh electrical engineering sounds fine and uh yeah and during my studies there there’s some time where you have to decide which direction which Fields you
Want to be in and then I decided okay microelectronics sounds somehow interesting and it’s uh sounds also useful because Dr already at this time was a micro Electronics Hub and with some big companies and smaller ones and so on and I said okay so microelectronics uh seem to be uh useful
In WR and yeah and that’s was the the start which brought me to to the AL world because then I had to find a topic for project Works later on uh and so on and I checked what was available at The Institute and then I saw something with
Al so there we we start I started this together with a with a friend so he was doing Al processes and a new self-built Al tool we had here in I think something like 2003 or four and and I was doing the the XPS analyzes of the films and
And our stuff so the mainly the Metrology and yeah this was the start so then I never left the AL world again so then after that I I had some internship at infinion uh also dealing with Al films and their their film properties so mainly uh film stress uh measurements
And and how process parameters affect film stress so which was a big Topic at this time um there and then yeah I I finished my my diploma also within yeah diploma Maes by which I have done at infinia at this time it was already kimonda so they changed the name and
Then split this the the D part uh from the the main company and called it kimona so I did my diploma thesis there and then fortunately I went back to University to to start working at the University because two years later um kimonda was bankrupted and then uh it
Was a good choice to not stay there also they they asked me of course for that yeah and yeah so at this time I have been already in Al a lot and and mainly and I still still am there it’s interesting that you said it was like 2003 that you kind of started
Doing doing aod stuff that’s pretty early on yeah right so at at this time I think uh infin was also starting with the topic and and then they we had some joint projects or at University have a joint project about this topic so with infinion and and this was the the
Starting point for the AL work at at our Institute so uh yeah there was someone who was pushing this uh you did at this time I think mainly solar stuff and also some cvd and P cvd and then they decided oh Al might be an interesting topic so
Infinion is interested in it and it’s something new and yeah this was starting point and there was an self-build tool and another I think a pcvd tool which was changed in a way that it can be used for Al and yeah this was the starting point and yeah you’re right it’s was
Quite early let’s say yeah yeah I guess good good place to be Dresden then if it was already microelectronics hope that kind of naturally place that Al was probably going to thrive at some point yeah of course so this was uh was a good place for that and yeah there there had been
Some let’s say more difficult times in the past also for Dr the micro Electronics so when we lost kimonda in I think it was 2008 or so uh so especially the politics uh decided that microelectronics is something which is not really important and that you can
Buy all the stuff cheaper in Asia and uh so it would have been easy to uh um to give some money to kimonda and they would have survived and uh and they really did this Leading Edge technology stuff uh which was after that it was yeah principles was gone from from
Europe so there’s nobody doing this uh Leading Edge stuff anymore like samung or tsmc is doing so so Europe lost some important part in the in the microelectronics industry with that and so now of course yeah they try to spend a lot of money to to have Intel here or
Maybe t C and so on uh but it’s much more money of course than uh having it spent 10 15 years ago and I think their own company doing this year yeah but at at the end or at the moment it’s fine so at the moment the politics uh is aware
Of uh the problems with micro electronics and that you cannot buy everything in Asia every time so Corona and and all the the problems after Awards uh showed that it’s maybe better to have also some own production in Europe and it’s the university always uh thought that is yeah not really an
Important topic for the University and there wasn’t much support and so on but this changed in the last years so yeah so there are now already things going on together with South Korea and or with tsmc and so on uh so the university is trying to push micro rics a little bit
Further so which which is good so we are happy about that that’s nice yeah that they kind of turn the thinking around at some point I imagine you know in the past 10 years somebody in in sax city was kicking themselves like how could we have let that company yeah yeah of
Course many people say this but at this time the the people who decided this or just said okay we we don’t need this so we we asked somebody and they told us we can buy this in Asia for cheaper and then did was the decision yeah so a lot
Of people shortterm Solutions yeah right yeah uh yeah I I I know that the there’s kind of the play on the Silicon Valley but there’s the the Silicon Saxony you of organization right is this something that has uh been around for a while or was this something new in like the past
Uh I I would think I I mean it’s it’s already old so it’s there for a long time uh but I cannot tell when it was fun founded um ah can can look this up but uh it’s it’s there already since I’m not sure maybe 20 years or so so really since a
Long time maybe it was even earlier uh so my my former Professor was one of the um the founders of that or he was involved in in the founding of the Silicon sexon there the idea was to have an something which is similar to Silicon Valley so a big uh network of companies
And universities and an institutes uh to uh yeah improve the the collaboration and the discussions and everything uh between all all of them um yeah which is of course important if you want to do microelectronics uh no there’s not a single company who is capable of doing
This so you need a lot of suppliers and uh companies and of course of course you need also a lot of institutes or universities uh which um yeah do take care of the education of the the students and so on because yeah you need the people and it’s not that easy to
Find some of them yeah which is also big Topic at the moment so all the companies recognize that it’s hard to find people for for their yeah for their business and there are a few people I’ve talked to on here that we have been trying to push like hey yeah if you’re
Interested in semiconductors or microelectronics like go study it because we really need you right now yeah yeah yeah and it’s somehow difficult so I can remember it was maybe something like 10 13 years ago maybe after the the bankruptcy of of kimonda so the the topic micro Electronics was not really
An Hot Topic and nobody wanted to do that so um from the the whole studies of electric engineering at our faculty there are I think five fields that students can go into and microelectronics is one field and at in that year just two students decided to go into that field of microelectronics
And it splits again into semiconductor technology uh chip design and so on so it was something like nothing so nobody did it and so this was maybe the the lowest point in the numbers of students but it’s still not really on a high level so there are not so
Many let’s say German students doing this but we have an international program so for an master program for Nano electronic systems as it’s called and this is something which is uh indeed growing so there is an every year a growing number of students uh but they are mainly from India um
China maybe the the Arabian country something like this a few from Europe of course uh few from Germany but mainly from abroad and there are still people interested and and being Engineers for for microelectronics so but in Germany it’s hard and I think as far as I know
It’s the same in in us and also in even in a country like South Korea where people think okay the micro Electronics is very important they all in in Taiwan uh and still and even there the the university has problems to find students uh who want to study something in this field
Here yeah I think even like people I know working in Al and working in in deposition and and these types of fields our natural people to go into micro Electronics afterwards still finish their PHD I mean myself included I’m in a marketing position now and don’t uh
See the value at least in going to be an engineer at one of these companies and field which is a shame but it is I mean it’s demanding work and it’s tough and it’s geopolitically odd to be in it as well so yeah it’s uh it’s It’s A Hard
Sell sometimes yeah but uh do you do you find that all the new activity in dresen for example um like tsmc iing there eventually and these these things is there like an injection of of interest from students in Germany now um it’s still hard to say um so I mean there as
I said there is this English study program and there is some big interest especially because people from India or so see this as a as a great possibility to yeah to to be an engineer and to find an global company uh which uh they can
Work at and so on um for the German students uh I think it will be like this but it it’s yeah maybe takes some time yeah so topic Bally um the problem is you always have to convince them the in school because after school they have to
Decide what they want to study and as long as in the school there’s no awareness of uh this field so that they can yeah study something which is related to microelectronics uh then it takes some time until um the the new students or the the former um pupils are aware of
That that there are some some possibility to study something which is related to microelectronics and that is easy to find a good job a well-paid job so uh so at least my students or the yeah the last students who finished their teases here or as long as I wasn’t
Able to convince them to stay at the University and do their PHD uh they started working somewhere else at a big company mainly and then also got paid very well and so on and yeah so so in principle if you are uh finishing school
And have you are not sure what to do and this is of course a good choice but maybe most of them don’t know yeah I think that’s that’s probably the case I mean it’s it reminds me of when I was in secondary school I mean
This was now now 10 years ago but we I I grew up in Upstate New York and there is some amount of like semiconductor help there as well tell is there IBM was there for a while Alin nanotech campus Global foundaries for for example and I was having a conversation not that long
Ago with someone who works in like the Department of Commerce for New York State and I was telling them like I I had no idea that this was a thing that was happening like right under my nose and I don’t think a lot of people um myself or like other than myself knew
Knew as well and even when I was in my bachelor’s program again just like no no awareness at all for this huge industry and hugely impactful industry his as well and like you know if that awareness was maybe raised a little bit more yeah you have to don’t want to use maybe the
Word groom but you know plant the seed a little bit earlier perhaps yeah so especially in in school I think so I’m uh um have two sons and the older one is already in the ninth grade and up to now there was nothing like um that they somehow uh realized that there’s a
Microelectronics industry and that would be a good field so there was some request exactly from his school and I was happy about it and then I sent what we can do together and and that uh we can give some talks about different topics and so on but yeah it it’s
Already a year ago and nothing happen so because yeah there are 28 uh kids in the class and the the teachers are really busy and so on so nobody has time to take care of these extra projects and yeah but I’m somehow optimistic at the
Moment so with with tsmc in the the big FBS which are already Inon from Bosch and inin and Global foundaries and uh and Intel in maor and so on so I think there is some new awareness of that topic and uh this at the end it will help somehow yeah let’s see how
Much but it will help of course absolutely yeah yeah speaking of of you like going to give a talk or giving some information to to some schools I would like to touch on some of the like Outreach that you do just in the the AL Community because you are a very active
Member in organizing events for the AL people in in Germany and atomic air processing people could you talk a little bit about some of the uh the organizations that you you work for and have started yeah so we um we started with something we called Al Le Dr so it
Was I think in 2010 um so there have been already some groups in in doing Al so one was at the frover for CNT uh one at our Institute and the nlab which is directly next to our Institute and and so we decided oh let’s let’s call it an like a network or
We we called it Al lab TR and to do some some things together and I mean we have been collaborating before already but this was the point where we decided okay we have maybe we can start some joint projects and maybe we can have some uh some meetings to discuss what everybody
Is doing and what new topics are and then um yeah it didn’t take long and then more groups join so because of the microelectronics industry there have been already a few uh research groups dealing with Al or at least they have been using Al so there are also groups doing something completely different
Than microelectronics but they simply need an Alum aluminum oxide film um sometimes and then they bought an Al tool and used it without doing any Al research but of course it was also planned to have them involved so that they learn something about Al although they they are just using the the process
And yeah it didn’t take long than colleagues from CET join and from somewhere else and then we decided I think in 2016 okay there are so many people from from somewhere else now we we have to call it Al lip sexon because it’s it’s
Not Al Le Dr anymore yeah and then in uh 2021 um we decided together also within with uh another let’s say network from the frown hover uh community that that we have to call it somehow more uh more general or more more German so not sexon
Anymore because there have been a lot of uh groups joining from also from far west part of Germany and so it’s wasn’t sexon anymore and then we we decided to call it Alpine so Atomic layer process Innovation Network so some someone came up with that idea and since I like
Mountains I decided that’s a good choice and um yeah then we so I organized the first let’s say big Workshop of this network in 2021 uh and it was very lucky because we have been in a in a time slot between two Corona or covid uh waves or how it’s
Called so we have been able to do this Workshop uh two weeks earlier it wasn’t possible and three weeks later also it wouldn’t have been possible anymore so and and everybody was really happy to to be there because they haven’t been allowed to go to any workshops or
Conferences since a year or more than a year um and yeah it was really successful so it was right at the beginning so the first workshop with something like 70 or 80 people from everywhere in Germany and already there somebody from Austria and so it wasn’t again Germany
Anymore um so the the idea was I mean there are Al conferences like the ABS conference and so on but um so the the costs are really high so if you have an conference in the US uh if you want to go there from Germany you have to pay
The flight the hotel the conference fees I mean you have to spend three 4,000 and there are a lot of groups with just a few people doing a and there’s simply not enough money for for traveling like this I mean sometimes one of them is is
Able to go there may often it’s just a professor and the PhD students are not able to to join such a conference and so the idea was to have an let’s say lowcost Workshop so there are up to now we we don’t have any conference fee or
Workshop fee so the the idea was to have an uh low uh lowlevel um cost so the best thing would be just travel costs no cost for the conference and then we are using sponsors to uh get the money for yeah for the the catering and
What what else is needed and yeah so the feedbacks is was quite good so there are a lot of people joining so there are sometimes groups uh attending with 15 people uh because yeah it’s possible for them so the conference fee isn’t there so they can just join
All together and everybody gets in contact with um yeah with new people and and can do networking and learn something and so on so I think that’s a good uh good thing we started yeah yeah and yeah the the second thing uh is the AL for industry Workshop or now it’s
Already also called like conference so we started this also maybe something like seven or eight years ago already and um there’s the European Society for thin films and they have some topical uh workshops every year on on special topics and that at that time they decided oh we should
Do a workshop on Al so that’s somehow an upcoming topic and and we did that and typically they we have workshops with I don’t know maybe 20 people are joining or something and then they have their break even and then their their conference fee is paying for most things
And then it’s fine for them and um yeah the first Workshop was also something like 80 people joined and uh we have been extremely happy about that because they uh yeah earned a lot of money which was uh useful for financing the other stuff they are doing and then they
Decide okay that’s that’s successful we have to do this next year again and yeah they waited that and um yeah since then we we have such a workshop every year I think in between it was also somewhere else not only in Dron but due to Corona
Uh we uh yeah we switch back to Dron and since they are also from Dron it’s easier for them to organize it here it’s more focused on industry so uh industry topics or how Al is used in industry so applications from industry and it’s also more from an yeah let’s say an industry
Um audience so for example if a company is thinking about how can we use Al way just decide okay we spend some money for a conference fee and send somebody there so that he can learn something about Al so there’s always a tutorial so half a
Day and then uh also see something about applications and how other companies are using Al and yeah so that works also quite good so the the Alpine Workshop is more f focused on let’s say research groups and so on but there are nevertheless there are still companies
Joining um which are interested in that or also want to uh uh get in contact with new students maybe and things like this and the AL for industry is more uh industry um focused let’s say yeah so this is what I mainly involved besides I
Was I was at both of those events this year both the a for industry and and March and then that Al be and where we met in uh in September and yeah they are really really fantastic events just thinking about two points that you made there yeah the conference expenses are
Are crazy the AL conference was in Washington state in the US this year and I mean there were so few Europeans there and it’s I mean it is a shame and that one is so Bellevue is so far away I mean it’s about as far as you can go other
Than Hawaii or Alaska in the US so it’s uh it’s crazy then yeah the yeah like having an industry session I think is is so like uh yeah it’s very it’s very brilliant because I find that the industry sessions at the AL conference are usually like the most well attended
As well so like a lot of people I mean both yeah students that are interested in hearing what companies are doing and the other companies hearing what what is new and just in in general like uh having some idea of the entire breadth of topics that actually go into industry
Is very is very useful I think you get especially as a student so focused on on one thing you forget that like once you leave Academia and you go to a company it’s like there are so many other things that you’re going to need to where yeah
Yes so Al is already in involved in so many fields I mean of course microelectronics is mainly a driver and this is where it came from or where it was used first in high volume production but there are so many even small companies using Al for some specific
Application and so on um so that it’s of course interesting for them and also for other companies to see how Al might help and in my opinion there are much more companies out there who might have some benefit of of using an Al process and they just not aware that there is some
Process working like that yeah so they they have maybe some some special parts and does need to be coded and they just don’t know that there is a process which is able to code the inner surface of their parts or something like that there so that might happen so I’ve been
Talking to people in the past who who joined the the AL for industry workshops for example and said yeah we just heard that there’s a process like this that’s exactly what’s interesting for us I’m not sure if they they use it now but at least there there was some interest and
That it might be a possibility for them maybe at the end they decide okay it’s still too slow too expensive whatever but even there there is a lot of progress ongoing in the last years in my opinion so um so the the tools aren’t that that expensive and the process is
Also not that expensive and that slow anymore so that’s why I think the the field is growing and more and more companies are are using it yeah it’s it’s good good marketing for institutes like yourself as well in case they need to do some proof of concept or so prary
Yeah of course so we we we just started a a project with a with a company and we have an yeah in carbon based membrane so they call it graphine membrane but it’s multi-layer so it’s it’s a carbon membrane and this membrane needs to be protected against an oxygen plasma
Because this is used in an environment where sometimes oxygen plasma is needed and so we uh had to find a way to protect this from the plas plasma but there are some more specific uh demands on the film so it has to be really lightweight and thin and so on and as
Most people know it’s hard to grow something on the graphine surface which is chemically inert or should be like that so you have to find some special tweaks to to to start your film growth and so on so there that’s why there’s a joint project and to develop in suitable
Coding for them and then it will be transferred to their production line and then will use it I’m pretty sure or they already are doing that and we want still want to optimize that and yeah speaking of some other things that you do for for industry we have a couple topics still
To go to go on here but I think it’s a nice segue into um like that you have a company um called ALS Metrology and uh you you talked a little bit about it at the Aline Workshop some of the qcm work that you were doing but yeah I’d like to
Hear a little bit about where the the inspiration for this company came and then what you’re you’re working on there yeah so it it all started that we have of course research Al tools and they are customized or at the beginning and some of them even have been self-built and um
So some especially our biggest a tour is really complex so there are a lot of things which can go wrong and they go wrong uh and at the end it’s still a big black box yeah so so you put a wafer in to take away out of the process and
Maybe it’s fine or maybe not and and you are wondering what was the reason why it’s not working like this and so there even already at the beginning there was some idea okay we have to find a way to have a look into the tool and see what’s
Happening there so we uh started with two methods uh we at first used our ellipsometer and connected it to a tool so we have some incu ellipsometry possibilities with some per windows and flanges so we can do ellipsometry during the deposition of a film and this is of
Course already really helpful to see how films growing and you can since ellipsometry is also very sensitive um you can uh yeah do just a few cycles of any specific process parameter setup and then see okay film growth was like this then you change something in your
Process then you repeat a few cycles and so on so that’s extremely helpful to to these processes and we did this in the first chamber and uh yeah there was the second chamber which I was using most um and there was no possibility to attach such an such an ellipsometer because
Yeah simply of the geometry of the tool um there was no no space and then so on no possibility to do this and then we s um we we saw in literature of course yeah people are using qcms to to monitor such an film growth and uh so then we
Decid okay that’s might be a good option for that and build something which could be in uh installed in that process chamber to to monitor the process and then of course we have to learn a lot of things so these qcms are really temperature sensitive and so so you can
If you’re doing it wrong uh you can just do argon pulses and it looks like a film deposition because of temperature changes and all these things and so yeah I was having this as a site projects all time and then de veloping this further and further um to to monitor our
Processes at that time I was throwing that at at conferences or workshops and then often people came afterwards and say oh that’s cool and where can I buy such a such a system to to monitor all process and I said ah it’s I build it everything by myself and there are some
Special things like I’m doing some temperature compensation by using two crystals in parallel and then you can calculate in Signal without the temperature effect and so on and yeah so it was simply not available something like this and also the the available qcm uh Hardware let’s say was not really
Useful for most Al tools so we started with something like this in in one chamber at the beginning and it was simply not possible because the most of these qcm sensors are made for PVD tools and then you just have a flange put this qcm sensor in of sight to your
Evaporation Source in the PVD system and then there’s some condensation of of material at the surface of the qcm you can measure that and that’s fine but in Al I mean you want to have the same film growth on the qcm like on your W or on
Your samples which mean you have to have at least the same temperature on your qcm you have the same gas flow to the qcm and so on so somehow it shouldn’t be it separate um sensor which is somehow inserted in the in the tool so I mean often it’s simply not possible because
Of the the tool design and even if it’s possible it’s still often not a good way to to do it like this and then uh I developed something which more or less looks like a big wafer with qcms it’s somehow the same film growth on the qcms
Like on the wafer you put in the chamber and um in my opinion this was the way to go to yeah to monitor exctly the film growth on this and yeah as I said and people have been asking for that and then how they can do it in their own lab
And their tools and then they had to say yeah that’s you cannot buy this sorry and and then I decided okay so maybe let’s found this a small company I mean I know how to build these things and how to use them and yeah this was the
Starting point and then I uh founded this founded this company and then yeah sold some systems already yeah that’s great yeah I I really I really like the The qcm Design This qcm wafer and I think people have this misconception that well Al is like always always ideal
And that every Al like every Al tool is not built the same you need to tweak a bunch of stuff and it’s not growing the same in every position in the chamber so uh yeah like you’re totally right when you say it is a black box inside there
Most of the time yeah yeah so I’m really convinced of this because I know how these tools are working and the processes are working and what can affect your process I mean there are so many parameters affecting this and uh I think most people are not really aware
Of this because yeah they simply don’t see these things so they just say okay our film is now a little bit thinner than last time and yeah who don’t who knows and uh if you are doing it for example with the qcm stuff and in more detail and faster then you might start
Seeing oh uh so the the bu level is affecting our dose of course I mean somebody somehow this is clear but uh then you can really see okay if I doing some uh some uh Control process uh which gives me a saturation curve when I do
This every week then I can see oh with the filling level of the bubbl I can see how this saturation curve is stretching to longer pulse times or higher um Buffalo temperatures or something like this so there are so many small things which can affect your
Process and most of the time it might be okay since you are in this typical saturation but there might be the point where your buo level for example is too low and then you start uh being under saturated and then your film is yeah simply not like it should be and then
Without these these special insights or the possibilities to to to obtain a saturation curve within a few minutes or something you start doing test process and trying to do this and this and you wonder wondering what could be the reason for that and so on you so and
That’s why I’m also really convinced of that because I’m using it a lot or we are using it a lot for even at different tools for different purposes um yeah it really helps a lot yeah I think you need to find a PhD student who’s really interested in microelectronics and also
Like Business Development you can ask them with this yeah yeah so I tried this in past I already had two and I thought I can convince them but at the end both left and went to a big company paying a lot of money and yeah but I have at the moment two PhD
Students and hope that there will be more and yeah they are interested and we’re also using of course the qcm stuff we have in in our tools um they they already know that it’s helpful and that I want to use it I I will also give a
Shout out to a former student of yours Marcel who became a postto in my group the last couple of years I was in CU Boulder yeah and uh he started doing some MLD work and built a insitu uh ellipsometer tool to do it in really
Great stuff with it yeah so we we shared an office many years and uh yeah he was also mainly responsible for our inc2 ellipsometry stuff we are doing uh so we have as I said we have one chamber with such equipment and yeah it’s it’s also
Useful of course so for example for the the already mentioned pro project on having a coding on this carbon film or carbon membrane there for example we want to use the ellipsometer because we want to see the film growth the initial film growth on the on the carbon surface
And that’s of course something we which what you can do with the ellipsometer of course we are also using like in vaku XPS to see how much um fil material is chemisorbed after the first cycle or after the first pulse of precursor and then how some pre-treatments can affect
This and can be uh changing the the amount of material and so on um yeah so that’s also something especially so the initial film growth which is very sensitive to a lot of things and is which is really hard to investigate if you don’t have this in C2 or at least in
Vaku possibilities to to do that you and of course ellipsometer is really nice and I like it I use it a lot especially is a ex to ellipsometer but of course also our ino ellipsometer for some special applications um and I’m also convinced that this is a useful thing but as I
Said you cannot uh use this in every tool and uh you can obtain a lot more information and data but it also it makes it more complexer and you have to find a suitable Optical model for your film and this can be quite difficult especially in the beginning if you start
Growing some islands and maybe film properties are different than in a in the bulky material and so on so you have to spend a lot of brain in that to to to have some useful information so if you’re able to do this then it’s really
Good so with the qcms as long as you get rid of the temperature problems um by by doing some compensation then it’s simply just Mass uptake or you can just see okay there’s a frequency change so it means there’s some mess uh attached to the surface both methods are fine yeah
Yeah and I know that Mel is really experienced in that so it was this main it his main topic here so he was mainly doing that yeah we we had an exitu lomer that we all knew how to use but I think once Marcel came our ability to get
Information out of it was was really skyrocketed from that point so yeah that’s that somehow became his passion so he he did it already in the in his diploma and then he yeah never stopped doing that so as as as well as I’m am addicted to qcm yes to to
Ellip it’s great you would you would love to work in the George labs they also really love qcm in that lab as well yeah I know yeah that’s yeah I mean that’s our our starting point that we saw that some groups using this in in let’s say really lab scale or self-build
Tool and that’s fine I mean there you can even find possibilities to use something like in standard qcm sensor or you can easily build something by your own but if you have a tool which is more like an yeah more similar to an industrial tool with which is capable of
Of coding 300 millimeter Wafers for example like like the tool we are using a lot uh then you are simply yeah not able to to use an standard qcm stuff and then you have have to find some some better solution yeah I do want to talk about the specific research topic also
That you work on that we chatted a bit about on our last call and that is the uh FL okay flash flash lamping Al or FD I guess flash lamp enhanced Al yeah so we have we have different names for that so depending on how you use it so we
Started with with that also many years ago so we bought a tool which has the possibility of doing Al or so some pcvd is possible and some flash lamp and kneeing and Flash lamp and kneeing means you have an kind of window on top of your samples and uh above this window
There are some cenon lamps and there are some big capacitors in our clean room basement and some long cables and big cables and then you can uh ignite light flash in these Canon lamps so they The Flash itself is just 1.8 milliseconds in length and um so the the light intensity
Is that high since you are igniting them with 2.5 or three th000 volts um so that you can heat up the surface of your sample or your wafer for 100 200 deges C strongly depends on on the material and the wafer and some other stuff so the the first idea was to
Use this as a just as a normal post treatment so having an Al process and then doing some flash lamp and kneeling so using it as a as a normal a kneeling step and of course yeah this is somehow working but it’s not that useful because
You can also use an RTP tool or normal fness or um although it maybe the different time scale of the kneeling step might change something and might change from properties but then of course we came up with the idea of well why not include the Flesh and baling in every cycle
Uh so then the the first um stuff was or the first idea was to do for example aluminum oxide at a low temperature but having this fles lamp and kneeling step uh in every cycle or in every second cycle or third or whatever and then checking the film properties and we have
Been able to show that you can do a process as 80° C and with the flashh in between so in in uh included in a cycle or at least in every second cycle uh we have been able to have the same film properties like density or refractive
Index uh like we have if we did the process at 250 Dees C so the flash lamp and kneeling was working um and was yeah somehow useful because as I said temperature of the substrate was lower of course you heat it up with the flesh but where you just heat up the surface
And most of the heat is spread into the bulk and then the bulk itself will remain at the lower temp temperature so the termal budget is much lower and yeah so this was successful already and then the idea came up okay so there are precursors which are used for cvd so
They are decomposed in a cvd process G by thermal decomposition um but they are also used for Al so they have a self-limiting um Behavior if they are chemisorbing at a surface so why not combine both and then the idea was to have an a precursor pulse coding the whole surface with
Precursor molecules and then afterwards uh replacing the second reactant like an oxidizing agent or some reducing agent by by using a flesh lamp and kneeling step to terally decompose the chisor molecules yeah and also again this was also working so we have been able to um for example do a titanium oxide
Deposition using ttip so titanium Tetris propoxide which already delivers titanium atoms and oxygen atoms so that was one of our first choices for that topic so we have some self limiting coverage of the surface and then afterwards we did in Flash Li and needing step to decompose these
Molecules and since this is a precursor which is also used for cvd it was working fine and the result was in titanium oxide surface and then you can start over with the next cycle it’s the surface is reactive again for ttip molecules so you can Cod them again with
A whole layer of ttip molecules and then do the next flash lamp and healing step and so on yeah and at the end there was an in film titanium oxide film grow growing just with one precursor so it’s a single Source process in combination with the flashlamp uh step and we didn’t
Have to use an oxidizing agent for example so which was the first idea to say okay we can grow an oxide fil but we don’t have to use an oxidizing agent Maybe that’s helpful if you have an uh insensitive substrate material which isn’t or it’s very reactive with uh
Water or ozone or whatever so you don’t want to have some oxidizing agent and of course the the overall goal is always to have a process for depositing metals or things which are more complicated to do with normal Al processes and so it’s planned to to have a joint project with
Anjana Dy she’s developing precursors and so on so the idea is to develop a precursor which can chemisorb in a self-limiting way like a normal Al precursor and if you correct them by termal decomposition then the result is something like a metal film something like this of course there are some there
Are some challenges to find something which uh decomposes to that film material and is still reactive for the next cycle of for the next precursor pulse um yeah but that’s what we think should be possible and will be somehow possible or at least you can do maybe
Some uh nitrate films or carites or whatever with interesting film Properties or um yeah with yeah a better way of doing it because you can maybe don’t have to use special plasma steps or so and these things yeah and that’s quite unique so I don’t think that
Somebody else has a tool like this up to now uh which combines Al and this fles lamp and kneeling um so yeah it’s interesting everything you you try and everything you do is is is new yeah yeah absolutely I haven’t seen it come up with anybody much anybody else other than than your
Names and yeah it’s I think a lot of like interesting implications I was going to ask if you could take you know some of these materials that typically you need to use plasma for because you can’t get enough energy and instead just do it uh with the the flashlight baling
A question about that that’s interesting if you are able to like replace plasma of course the whole like you know downside people say for Plasma’s conformality what is the ability of this to do like high ratio stuff so yeah so um the so we tried this of course and so
The flash lamp is heating this the let’s say the top microns of a silicon wer so maybe down to five microns or so that’s the the region or the volume where the flash lamp light is uh absorbed and this is where you generate the Heat and we also did some
Experiments with uh yeah structures of 3D features like through silicon VR and so on and I don’t have the number right now but we have been able to have in conformal coding at least to a few Micron steps so I I cannot tell if it
Was three five or 10 I don’t know uh but it was possible to have an um with exactly this process with the titanium titanium oxide for example uh we have SE in the sem pictures in the cross-section that there was the same film thickness
At the top of the wafer like uh maybe a few micrometers in in the depth of the 3D feature yeah of course it’s not like having a a coding in in the depth of 200 micrometers or something like this what normal Al should be able to do uh so
It’s more surface uh more surface process but it works at least for for some depth yeah so conformality can be fine I mean the the overall principle is that the the first step so the precursor step is like in a normal Al process and it’s self-limiting so you can just have
A big dose and deliver enough for coding the whole surface and then the The Flash lamp step can decompose everything so it doesn’t need to be self-limiting of course uh just changing everything but it’s the same in in most Al processes I mean if you do a water step in an in an
Oxide process the water will also oxidize every everything and wouldn’t stop on the on the surface maybe but since there’s just one layer which can be oxidized it’s it’s Al and uh so with the The Flash lamp based process it’s the same sometimes we even have to do
Multiple flashes so for some specific precursors maybe our maximum flash light intensity is not sufficient uh or if you want to um yeah I want to reduce the the workload for Flash lamps or something like this then can also do lower energy but multiple flashes things like this
And yeah so the tool is of course also a prototype so if you want to use this in on bigger scale substrate and things like this this is also possible I mean there are uh there are groups using flash lamp and kneeling in in different uh Fields let’s say not for Al related
Topics and also on bigger uh sizes I mean also in in microelectronics Industry I think fles lamp anding is used to do some uh dopent activation or things like this so people might are using this on 300 mm Wafers and so on yeah that’s fantastic it’s very it’s
Very cool I I think in is there a a uh a chance that this could be scaled to something like a batch tool or like maybe a spatial kind of uh configuration so uh I think it’s wouldn’t be possible for a batch tool since you always have
To have to have this line of sight between your flash lamps and and and your Wafers so it will be always something like single wafer tool but or the the spatial stuff is also possible so we have been in contact with a company in the past um way did um yeah
Codings on very big glass substrate so meter scale stuff and we have been using flash lamps a row of flash lamps or more of them more rows um to do this kneeling of the of these substrates so and this was some kind like a spatial process so the substrate was moving underneath the
Flesh lamp and the Flash lamp has been igniting their flashes I something like 10 Hertz so 10 times a second and the the substrate was going underneath and was heated on every in every area of the substrate so in principle of course this is is possible yeah so I mean we have to
Do our our stuff first and have to develop useful processes and do the proof of concept and how it should be done and then maybe yeah that’s also an idea to to use this in a spatial tool to have someing step in between so very short and kneeling step with low termal
Budget but still uh improving film Properties or changing something at least yeah should be possible sounds like there is some kind of road map for this technology then yeah somehow yeah yeah oh good that that’s fantastic uh Martin this has been really really great we’ve had pretty
Deep conversation here about a lot of a lot of topics in in an hour um do you have any any parting words as we finish up here for people in Al micro Electronics anything you’d like to uh any wisdom you’d like to relate for us
Uh wow that’s that’s a b good I mean everybody should know now that they have to use qcms I hope so at least yeah uh no yeah so I’m I’m still convinced of that topic and Al so it’s a growing field and it’s interesting so I’m happy
About everybody who is related to this and it’s interested in in Al and doing research on that and yeah so I’m looking forward to meet most of you all of you next time at the next Workshop next conferences talk about everything um yeah and also looking forward to the
Next podcast and let’s see what other people are uh talking about and so on that’s right last Thursday of every month if people who are listening don’t know that yet okay very good thanks thanks a lot Martin for joining me today this was really really quite nice and
Yeah I’ll probably look forward to seeing you at whatever German community aod event that is happening next so okay yeah yeah so you’re welcome and and thank you for for asking me for having this conversation was interesting I’m looking forward to do to the yeah to the
Podcast and also to the next one as I said so cool great thanks Mar take care okay you’re welcome have a nice week thanks for listening to Al stories with benck to stay updated on new episodes each month please follow us on Spotify Apple podcast or Google podcasts
We hope you enjoyed the show I hope to see you again in the next one