The career path of Dr. Rudy Wojtecki spans from sequencing mitochondrial DNA, to use of atomic force microscopy, to NMR studies and on to applying his polymer chemistry skillset to help push the boundaries of nanoscale science at IBM. In this episode, Paolo and Rudy discuss how technology is pushing boundaries to produce semiconductor features into the low nanometer size range, which in turn brings up questions about the limits of Moore’s law. Tune in to learn about the diverse and interesting work our guest does at his dream job.
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The unstoppable progress in computational power that we have experienced in the last few decades, and that has changed the world as we know it, is almost entirely due to the relentless efforts of cramming an increasing number of transistors in microprocessors. Moore’s law, predicting a linear increase in microchip transistor density, doubling every two years, has been consistently proven right, but we are now approaching physical limitations as resolution breaking the 5 nm barrier is quickly approaching molecular dimensions. This is why many think Moore’s law is dead and this is why Rudy Wojtecki and the conventions-challenging teams at IBM Almaden Research Center are working on developing new paradigms for the computers of the future.
Rudy is a polymer chemist by background and a true multidisciplinary scientist at heart. His work on self-assembling polymers and surface chemistry is innovating the way microchips are manufactured, and the way research is done at Almaden is providing a brilliant example of different scientific disciplines working together to accelerate progress.
Dr. Rudy Wojtecki 0:06
Right now, we're pushing the boundaries beyond the seven nanometer technology node. So, the size of our features are in, you know, the 10s of nanometers scale.
Paolo 0:19
Dr. Rudy Wojtecki always knew that he wanted to work for IBM. One thing led to another, and that's exactly what he's doing today. Blazing new trails, at the Almaden Research and Innovation Laboratory. In this season two episode of Bringing Chemistry to Life, we speak with another member of Chemical and Engineering News' 2020, Talented 12 about their work and trends in their field. I'm your host, Dr. Paolo Braiuca, from Thermo Fisher Scientific. We began by asking Dr. Wojtecki about where he found his original scientific inspiration.
Dr. Rudy Wojtecki 1:00
I really gravitated towards chemistry and synthesis, in particular, because it was a way of manipulating matter to build useful molecules, useful materials in general. So, it's part of that creative process that I really enjoy exploiting I guess, science and, and that understanding of the world around you.
Paolo 1:23
IBM is not the first place you will think of for a chemist, right? And yet chemistry is your your main background, but of course, you need to crosslink your chemical skills, with, you know, the the engineering skills that go into making these electronic devices and an old technology that is behind? And I you know, how much would you say that your general interest in science and you, you being a curious person is is very important so far for yourself.
Dr. Rudy Wojtecki 1:51
I think that's a very critical mindset to have going into working at someplace like a research outfit, like IBM Research in general. Because it, it helps you engage with other people and in very different project areas, because there may be some part of those projects that you, you may not have thought you could contribute to it. But looking at it through a different perspective and providing some additional value through that perspective is something that I think, helps you broaden how you can impact technology in general. So, you know, I've been engaged in a lot of different project areas within IBM. Some of them are in electronic devices, some of them are in, in fundamental studies of chemistry. And in that technology, space, there's, there's so many different ways you can apply that, that skill set of chemistry to different problems. From, you know, fabricating devices to packaging them, to making, you know, your conventional transistor based devices to making some of the more exploratory devices involving things like superconductors, or maybe unique material sets. So having that curiosity in general as a as a fundamental passion is something that really is well suited for, for a research environment like this. The link between chemistry and polymer chemistry at that and IBM, even as an undergraduate, I didn't really make that connection. But in graduate school, my my mentor and my research mentor, Stuart Rowan, he worked for the same group as what who became my first manager, Al Nelson. And at that point, you could see how chemistry played such a significant role in the microelectronics industry where in Almaden, in particular, it was the the birthplace of the chemically amplified resist. And this is what really enabled Moore's law and enabled us to reach the the technology nodes that we're at right now, from the use of those type of polymeric responsive materials.
Paolo 4:34
So the the opportunity of fulfilling your dream, or joining IBM, came through the connection between your PhD mentor and and you know his, basically his network, right. So eventually you made it. So was was that was it an obvious move after you completed your PhD and your your graduate studies?
Dr. Rudy Wojteck i4:55
No, actually, I was looking at some other postdoc opportunities to work in things like drug delivery in producing macromolecular architectures to do that. And this opportunity at IBM came about because there were two people that retired at Almaden. And it just so happened that my skill set in, in my research project, at Case Western was in making some very complex polymeric architectures that required some very advanced NMR techniques like diffusion NMR, fluorine, carbon, 2D NMR. And so it was, it was a really good fit, given my skill set. And this opportunity that came about was an associate engineer, and most people that want to be research staff members generally go through a postdoc position. So, it was a little bit of an unconventional way to, to get into IBM, and then to go from there.
Paolo 6:01
So is it true that you worked on a number of side projects, as you were, you know, in your initial position in the NMR team, and this sort of, you know, involvement in the side projects were was actually instrumental in your career development inside the organization?
Dr. Rudy Wojtecki 6:18
Absolutely. This was a significant goal of mine to become a part of this research organization, given its, you know, very distinguished history and all of the amazing technology that has come out of the organization and the company in general, and the people at Almaden have that scientific reputation. So, as I joined, of course, I want to work with some of the world's leading scientists in in polymeric synthesis and developing materials for electronics. And so being that very curious person, I talked to people and tried to leverage the skill set of NMR characterization and using some of these techniques like diffusion NMR, to advance their research, and to help them characterize some of the materials that they've been making. And that link was very valuable. What's really unique about the IBM Research and Almaden is there's this collegial atmosphere here, where if if somebody needs help, people tend to help them. Or if somebody has questions, there's, there's a very collaborative environment here. And I think that's particularly unique, because the other end of the spectrum is siloing, individual projects not talking to one another. But that's the exact opposite of what I experienced here at Almaden; it really is a research community.
Paolo 7:54
And I guess being curious and able to work across disciplines and understanding problems or being interested in problems is is what makes this involvement right with it with a broader research community at the site's easier.
Dr. Rudy Wojtecki 8:10
When it comes to electronic hardware, as you said, it's a very interdisciplinary field. My background in polymer chemistry and synthesis, may be able to help address one part of a much larger problem, but you have to have teams of people, you have to have groups of people that have different perspectives, whether it's an electrical engineer, or a designer, or somebody that's heavily interested in, or are very well equipped to do things like chemical vapor deposition. So, it really takes all of those different perspectives to move things along. And so, in order to do that, you go much further working on those teams rather than trying to work alone.
Paolo 8:55
I like to go down into some of the details of what you and your team are, are pursuing. And and you know, what, what can you tell us about the work you're, you're leading at the moment in IBM, and what's the directions and, you know, how do you apply your chemical knowledge to to, you know, the the technology problems that IBM is, is addressing,
Dr. Rudy Wojtecki 9:16
There's one focal point that we're working on right now, and that is in area-selective depositions. It's a very simple goal. And that is if you envision a patterned surface, and let's just for the sake of this discussion, we just say it's a planar surface. And you may have lines of a metal and spaced in between that metal you'll have dielectric and that may be something like silicon, it could be silicon nitride, silicon oxycarbide things along those lines. So, with that pre-pattern, the idea is you want to expose that to a process that would then selectively grow a film on one of those surfaces, so, so you want to create topography on your surface. So, you start with a co-planar surface, you want to deposit a dielectric. And that creates maybe some bumps on the surface. And that's actually particularly useful in advanced technology nodes. And there are other applications here, you can also do, for instance, you can put a metal selectively on a metal, all of these are very useful processes, if you're going to actually build a device or extend your ability to make devices at smaller and smaller feature scales. And so that's the overall problem that we're trying to address. And, again, coming at this from the perspective of applying chemistry and synthetic development to that, this field has been established in the last 15 years by some amazing pioneers that have demonstrated that type of work. In the literature, we observe that there were maybe a handful of organic molecules that were used to achieve that. And that small number of molecules made us wonder, well, maybe we could synthesize a better version of these or ones that achieve more selective growth or being able to deposit films at higher temperatures or reducing things to like, lateral overgrowth, or if it's an isotropic film formation. We applied that, that lens and were able to show that with the introduction of things like cross-linking groups, we could reduce defectivity of that type of process. And, and, and maybe it's useful to say that if you're working in developing a technology for electronics, the bar is incredibly high for you to to, to to make something or implement one of these processes in a technology that would go into high volume manufacturing.
Paolo 12:06
And I guess it gets more and more challenging as you squeeze more transistors in into the same surface right. And so, the distances become smaller and smaller in your pattern. So, your level of precision needs to actually increase while you keep the defectivity very low. What kind of chemistry you leverage for you know growing these films on semiconductor types of surfaces or a metal type of surfaces, can you give us some examples?
Dr. Rudy Wojtecki 12:30
For an area selective deposition, you typically start with these pre-patterned surfaces, surfaces. And as I said, you generally start with a metal versus a dielectric. So, if you want to have an organic material selectively stick on one of those surfaces, you have to exploit some type of surface chemistry that may only happen between a metal and organic, and doesn't happen between a dielectric like silicon, silicon nitride and silicon oxycarbide and that organic material. So, in graduate school, I worked on developing a synthetic method for making mechanically interlocked rings. And what we did is we used a templated synthetic approach that involved metal-ligand interactions. And in that respect, we we exploited things like nitrogen containing ligands that bound in a very selective manner with a metal like zinc. We've done iron, we've done a variety of other metals, but that super-molecular interaction between a metal and an organic is the same thing that we exploit for this area selective deposition. So, the ligand may not be as bulky organic, it may be as simple as something that looks like a surfactant where you may have phosphonic acid at one end of the molecule. And at the other end, you have some reactive groups or some long chain in that interaction between the ligand and your metal, you can exploit that to have your organic selectively stick on the surfaces. And it's that type of of super-molecular metal ligand interaction that we exploit to achieve this type of deposition.
Paolo 14:17
What kinds of selectivity or spatial resolution you can achieve with the sort of chemistry? Is it in a nanometer? Sub-nanometer kind of scale?
Dr. Rudy Wojtecki 14:27
It all depends on your incoming structure. Right now, we're pushing the boundaries beyond the seven-nanometer technology node. So, the size of our features are in, you know, the 10s of nanometers scales. But that isn't necessarily a fundamental limitation for this process. I haven't pushed it beyond those structures that we we typically get from our colleagues and collaborators at IBM semiconductor research. So, you know, there are groups at Almaden that have the capabilities of moving atoms on the surface and being able to look at atomic resolution, but we we haven't gone beyond the, these incoming structures at this point. So, but I don't, I don't think there's necessarily an upper boundary, or maybe a lower boundary in terms of the size scale for these.
Paolo 15:31
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You mentioned lens and this makes me think about lithography again. During, during last year's Futures Festival, you describe the use of additive lithography as a sort of an additional tool to improve selectivity on on the films you grow. Can you describe how that works?
Dr. Rudy Wojtecki 16:12
Certainly, and maybe, to put this in context, for the overall trends that you can observe in, in semiconductor research in general, you, you can observe that, as you push resolution, your resists tend to get thinner and thinner. If you compare using something like a resist for, in printing with that in a 248-nanometer exposure versus extreme ultraviolet, that the thickness of your resists are very different, and much thinner when they come to the UV resist if you're pushing resolution limits. And you start to see other types of materials for those smaller feature sizes, and printing and UV come online and start to be implemented, like inorganic resists, for instance. And those are still quite thin. So where do you go from there? And in a conventional lithography sense, you can envision, well, I can certainly create a monolayer of an organic material at a surface but if I were to expose that, what would I do with it. And your ability to develop and typically with a resist, what you'll do is you'll expose it, and there'll be some type of liquid developer that you use to remove portions of the film unexposed portions of the film in one tone, and in another, the exposed areas. And that's what allows you to print those features. So, if you have a monolayer of material, and even if you were to remove portions of that, well, what do you do with that? If you try and do pattern transfer through some etching process, that organic material etches very quickly, and it'd be very difficult to get a very nice pattern into silicon as a result of that. So, the other thing you can do with that, because these are organic materials tend to have no dangling bonds that would nucleate different types of ALD growth, you can use those type of monolayers as a way to selectively grow your film in an area. So, this is to contrast, a conventional way of going about lithography to challenge this idea that instead of subtracting and then etching, or maybe you can do an exposure, and then just grow a film where you want it. Another point to this, or another part to this, this idea was this idea of additive lithography. If you have the correct type of molecules, and if you start with a pre-patterned surface, well, now you have a type of photoactive material that will selectively adhere to a metal portion of your film. And so, it gives you another tool set to allow you to have a self-aligned type of of component to your resist. And this idea of self-aligning touches on one of the, the immense technical challenges as you push that critical resolution, as you start to try and make even smaller feature sizes and what we can do today. And again, if you think about how a device is made, it's it's layer by layer by layer by layer. Again, starting with the front end, the middle of the line, and each one of those steps requires an alignment process. So, if you're using lithography to align to that front end so that you can put contacts to your devices, you better have something that is incredibly precise because deviations to alignment in nanometer regime can lead to things like loss of device yield or shorting of devices. Or even if you get a wire too close to another, you can start to lead to device variability or hotspots in your devices where there may be some thermal migration or increases in local thermal temperatures that can cost you performance. So having more processes that are self- aligning is something that I think may impact our ability to make these devices in the future.
Paolo 20:34
Is there anything else disrupting on the horizon that you can share? Or is there anything upcoming that is particularly revolutionary in the in the work that you guys are doing over there?
Dr. Rudy Wojtecki 20:46
One area, and I won't go into the exact specifics, but that notion, that thesis of, of rethinking, materials in general is one that we're exploiting for materials and in the electronics applications. And if you think about it, now, the conventional perspective on materials is, is generally a structural material. So, if you look around your room right now, or if you if you think about the materials that you use, that are plastic are well, that are polymers. In those type of materials, every effort is made to minimize bonds from breaking. And that's sort of a traditional notion of how people have, have thought about making new materials in this idea of using a dynamic bond, it's the exact opposite. It's being able to break and reform bonds, reversibly. And you can do that with these dynamic covalent type of units like disulfides that will undergo disulfide metathesis when they're exposed to light, or Diels Alder chemistry that will undergo reversible reactions, retro Diels Alder reactions, at elevated temperatures. And if you put those in a material, you can achieve all a spectrum of different types of macroscopic properties. So, for instance, you can make things like shape memory polymers, you can make self-healing materials. So, if I have a polymeric material, I can scratch it, or I can break it and then mend it back together. And even that sounds simple. But that's very difficult to achieve with your conventional polymers. And if you break a bottle, you're not going to put it back together. And so, using that type of process of being able to break and reversibly reform bonds, is very useful. And I think it has a number of different types of applications for electronics, some of which may be in packaging materials. Some of that may be in these selective depositions, I think the application in the electronics space makes a lot of sense, because you can you can extend your ability to fabricate increasingly complex devices, whether they're modular devices for things like heterogeneous integration, or whether or not they're useful in a variety of other types of applications. I think it certainly is a very attractive perspective to use it in that.
Paolo 23:41
I, we're coming to the end of our chat, because I cannot I cannot keep you here all day, of course. And and there's always a final question I asked, but before going there, there's one thing I really really have to ask. Is it really true that you invented a new method for decaffeinating coffee?
Dr. Rudy Wojtecki 23:59
We did it and that was a, you know, another story unto itself. And we were actually working on this, this this project where we were trying to leverage what were often referred to as these solid functionalized particles to try and remove different materials from effluent streams. So, for instance, we design polymeric particle with a receptor that we wanted to bind specifically to molecules so that you could, you know, add this to remove impurities in oil and gas, or in medical applications. So, and, and caffeine was a very nice model system for this and may have applications by itself. Well, none of this really worked particularly well, when we tried to design a receptor specifically for caffeine. And we were looking at things like hydrogen bonding. And you can imagine designing a hydrogen bonding receptor and trying to remove caffeine from water doesn't work well, because water also was a very good hydrogen bonder, so you had a lot of competition between what you're trying to remove and the solvent that it's in at the time. So, we looked at different types of platforms, like, in the case that you're referring to, clay was particularly useful in binding to caffeine. And people have shown that before, but what we did a little bit differently was selectively removing caffeine and trying to leave as many of those other flavor molecules as other components in coffee. And so, what we did is, we tried to find a more environmentally friendly way to go about removing caffeine and decaffeinating coffee in a selective manner to retain the taste. And so, what we ended up doing is pre-treating our clay and saturating it with some of the other components in coffee. And that allowed us to remove caffeine up to 93 mole percent as we could see it. And it was a simple solution. But it's something that worked very effectively.
Paolo 26:19
This is a fascinating discussion, Rudy, that thank thanks, thank thank you very much. You know, you work on some incredibly fascinating challenges. And you work with a lot of extremely talented people in in a in a very stimulating environment. So, if you if you had to stop and look back, what would be one piece of advice you'd pass on to a young scientist just starting their career?
Dr. Rudy Wojtecki 26:43
I would say that continue with science. That anyone that's interested in it, and is thinking about pursuing a career in science, we certainly need more scientists in the in this world to tackle some of the societal problems in general. I mean there's all those are, there's a host of challenges to solve. And in things like reducing the number, the amount of, of greenhouse gases, making materials more efficient. There's so many different problems to look at and solve. So, I would strongly encourage anyone that's interested in science to pursue those careers. And I think it benefits community locally, as well as our, our society as a whole. There are so many different types of benefits that you can, you may not even anticipate your work contributing to. And I often like to think about some of the, you know, fundamental experiments from when people studied the fundamentals of the atom. And at the time, they couldn't see direct applications for any of this, they just wanted to understand why this behaved the way it did. And, you know, as a result of this fundamental experiments, we now have things like MRI that takes advantage of those fundamental concepts and understandings. And, and just think about that alone, the impact of having the ability to look inside people that are still alive instead of having to perform surgery. I mean, it's a huge impact that you can make, and sometimes that the impact may go beyond what you could conceive of at the time. So, I always think it's fascinating to see where technology goes in unanticipated directions. Because you can only see so far in terms of your information, the landscape of of what you think is possible. But a lot of times things happen that you wouldn't have even guessed about. So those people interested in science. Please, please continue to pursue those careers and continue to be engaged and interested in that.
Paolo 29:12
That was Dr. Rudy Wojtecki, a researcher at IBM Almaden Lab, and one of the Chemical and Engineering News' Talented 12. Thanks for joining us for this season two episode of Bringing Chemistry to Life and keep an ear out for more. If you enjoy this conversation, you're sure to enjoy Dr. Wojtecki's book, video, podcast and other content recommendations. You can download them visiting thermofisher.com/BCTL. And this is also where you can request your free Bringing Chemistry to Life t-shirt. You can find the URL in the Episode Notes as well for super easy access. Just check your podcast app. This episode was produced by Matt Ferris, Matthew Stock and Emma-Jean Weinstein.