Samuel Ok. Moore Hello. I’m Samuel K. Moore for IEEE Spectrum‘s Fixing the Future podcast. Earlier than we begin, I wish to let you know which you could get the most recent protection from a few of Spectrum‘s most necessary beats, together with AI, climate change, and robotics, by signing up for considered one of our free newsletters. Simply go to spectrum.ieee.org/newsletters to subscribe. The semiconductor business is within the midst of a significant enlargement pushed by the seemingly insatiable calls for of AI, the addition of extra intelligence in transportation, and nationwide safety issues, amongst many different issues. Governments and the business itself are beginning to fear what this enlargement would possibly imply for chip-making’s carbon footprint and its sustainability usually. Can we make all the pieces in our world smarter with out worsening local weather change? I’m right here with somebody who’s serving to determine the reply. Lizzie Boakes is a life cycle analyst within the Sustainable Semiconductor Applied sciences and Techniques Program at IMEC, the Belgium-based nanotech analysis group. Welcome, Lizzie.
Lizzie Boakes: Hiya.
Moore: Thanks very a lot for coming to speak with us.
Boakes: You’re welcome. Pleasure to be right here.
Moore: So let’s begin with, simply how huge is the carbon footprint of the semiconductor business? And is it actually sufficiently big for us to fret about?
Boakes: Yeah. So quantifying the carbon footprint of the semiconductor business shouldn’t be a simple job in any respect, and that’s as a result of semiconductors at the moment are embedded in so many industries. So the obvious business is the ICT business, which is estimated to be about roughly 3 p.c of the worldwide emissions. Nonetheless, semiconductors may also be present in so many different industries, and their embedded nature is rising dramatically. In order that they’re embedded in automotives, they’re embedded in healthcare functions, so far as aerospace and protection functions too. So their enlargement and adoption of semiconductors in all of those completely different industries simply makes it very onerous to quantify.
And the worldwide influence of the semiconductor chip manufacturing itself is anticipated to extend as properly due to the truth that we want an increasing number of of those chips. So the worldwide chip market is projected to have a 7 p.c compound annual development price within the subsequent coming years. And taking into account that the manufacturing of the IC chips itself usually accounts for the most important share of the life cycle local weather influence, particularly for consumer electronics, as an illustration. This enhance in demand for therefore many chips and the demand for the manufacturing of these chips may have a major influence on the local weather influence of the semiconductor business. So it’s actually essential that we give attention to this and we establish the challenges and attempt to work in the direction of lowering the influence to realize any of our ambitions at reaching internet zero earlier than 2050.
Moore: Okay. So the way in which you checked out this, it was form of a— it was cradle-to-gate life cycle. Are you able to form of clarify what that entails, what that actually means?
Boakes: Yeah. So cradle to gate right here implies that we quantify the local weather impacts, not solely of the IC manufacturing processes that happen contained in the semiconductor fab, but additionally we quantify the embedded influence of the entire vitality and materials flows which can be coming into the fab which can be mandatory for the fab to function. So in different phrases, we attempt to quantify the local weather influence of the worth chain upstream to the fab itself, and that’s the place the cradle begins. So the extraction of the entire supplies that you simply want, the entire vitality sources. For example, the extraction of coal for electrical energy manufacturing. That’s the cradle. And the gate refers back to the level the place you cease the evaluation, you cease the quantification of the influence. And in our case, that’s the finish of the processing of the silicon wafer for a particular expertise node.
Moore: Okay. So it stops mainly if you’ve acquired the die, nevertheless it hasn’t been packaged and put in a pc.
Boakes: Precisely.
Moore: And so why do you’re feeling like you must take a look at all of the upstream stuff {that a} chip-maker might not likely have any management over, like coal and such like that?
Boakes: So there’s a huge want to research your scope by what known as— in greenhouse gasoline protocol, you’ve three completely different scopes. Your scope one is your direct emissions. Your scope two is the emissions associated to the electrical energy consumption and the manufacturing of electrical energy that you’ve got consumed in your operation. And scope three is mainly all the pieces else, and lots of people begin with scope three, all of their upstream supplies. And it does have— it’s clearly the most important scope as a result of it’s all the pieces else aside from what you’re doing. And I believe it’s essential to coordinate your provide chain so that you simply be sure you’re doing probably the most sustainable answer which you could. So if there are— you’ve energy in your buying, you’ve energy over the way you select your provide chain. And for those who can manipulate it in a method the place you’ve decreased emissions, then that ought to be achieved. Typically, scope three is the most important proportion of the entire influence, A, as a result of it’s one of many largest teams, however B, as a result of there’s loads of supplies and issues coming in. So yeah, it’s mandatory to take a look up there and see how one can greatest cut back your emissions. And yeah, you’ll be able to have energy in your affect over what you select ultimately, by way of what you’re buying.
Moore: All proper. So in your evaluation, what did you see as form of the largest contributors to the chip fabs carbon output?
Boakes: So with out efficient abatement, the processed gases which can be launched as direct emissions, they’d actually dominate the entire emissions of the IC chip manufacturing. And it is because the processed gases which can be usually consumed in IC manufacturing, they’ve a really excessive GWP worth. So if you don’t abate them and you don’t destroy them in a small abatement system, then their emissions and contribution to world warming are very giant. Nonetheless, you’ll be able to drastically cut back that emission already by deploying efficient abatements on particular course of areas, the high-impact course of areas. And for those who do this, then this distribution shifts.
So then you definitely would see that the direct emission– the contribution of the direct emissions would scale back since you’ve decreased your direct emission output. However then the next-biggest contributor can be {the electrical} vitality. So the scope to the emissions which can be associated to the manufacturing of the electrical energy that you simply’re consuming. And as you’ll be able to think about, IC manufacturing could be very energy-intensive. So there’s loads of electrical energy coming in, so it’s mandatory then to attempt to begin to decarbonize your electrical energy supplier or cut back your carbon depth of your electrical energy that you simply’re buying.
After which when you do this step, you’d additionally see that once more the distribution adjustments, and your scope three, your upstream supplies, would then be the most important contributors to the entire influence. And the supplies that we’ve recognized as being probably the most or the most important contributors to that influence can be, as an illustration, the silicon wafers themselves, the uncooked wafers earlier than you begin processing, in addition to moist chemical substances. So these are chemical substances which can be very particular to the semiconductor business. There’s loads of consumption there, and so they’re very particular and have a excessive GWP worth.
Moore: Okay. So if we might begin with— unpack a couple of of these. First off, what are a few of these chemical substances, and are they often abated properly as of late? Or is that this form of one thing that’s nonetheless a coming downside?
Boakes: Yeah. In order that they might be from particular photoresists to— there’s a very heavy consumption of primary chemical substances for neutralization of wastewater, these kinds of issues. So there’s a mixture of getting in a excessive embedded GWP worth, which implies that it takes a really great amount of– or has a really giant influence to provide the chemical itself, otherwise you simply have quite a bit that you simply’re consuming of it. So it might need a low embedded influence, however you’re simply utilizing a lot of it that, ultimately, it’s the upper contributor anyway. So you’ve two sort of buckets there. And yeah, it will simply be a matter of, you must multiply by the quantities by your embedded emission to see which of them come on prime. However yeah, we see that usually, the wastewater remedy makes use of loads of these chemical substances only for neutralization and remedy of wastewater on web site, in addition to very particular chemical substances for the semiconductor business reminiscent of photoresists and CMP cleans, these varieties of very particular chemistries which, once more, it’s troublesome to quantify the embedded influence of as a result of usually there’s a proprietary— you don’t precisely know what goes into it, and it’s loads of problem attempting to really characterize these chemical substances appropriately. So usually we apply a proxy worth to these. So that is one thing that we would love to enhance sooner or later can be having extra communication with our provide chain and actually understanding what the true embedded influence of these chemical substances can be. That is one thing that we actually would want to work on to actually establish the high-impact chemical substances and take a look at something we are able to to scale back them.
Moore: Okay. And what about these direct greenhouse gasoline emission chemical substances? Are these usually abated, or is that one thing that’s nonetheless being labored on?
Boakes: So there’s fairly, yeah, a considerable quantity of labor going into the abatement system. So now we have the standard methane combustion of processed gases. There’s additionally now improvement in plasma abatement techniques. So there are completely different abatement techniques being developed, and their effectiveness is kind of excessive. Nonetheless, we don’t have such a very good oversight in the intervening time on the quantity of abatement that’s being deployed in high-volume manufacturing. This, once more, is kind of a delicate subject to debate from a analysis perspective if you don’t have perception into the fab itself. So asking specific questions on how a lot abatement is deployed on sure instruments shouldn’t be such straightforward information to come back throughout.
So we regularly go along with fashions. So we apply the IPCC Tier 2c mannequin the place, mainly, you calculate the direct emissions by how a lot you’ve used. So it’s a mathematical mannequin based mostly on how a lot you’ve consumed. There’s a mannequin that generates the quantities that might be emitted immediately into the environment. So that is the mannequin that we’ve utilized. And we see that, yeah, it does correlate generally with the top-down reporting that comes from the business. So yeah, I believe there’s loads of method ahead the place we are able to begin evaluating top-down reporting to those bottom-up fashions that we’ve been producing from a sort of analysis perspective. So yeah, there’s nonetheless loads of work to do to match these.
Moore: Okay. Are there any specific nasties by way of what these chemical substances are? I don’t assume persons are accustomed to actually what comes out of the smokestack of chip fab.
Boakes: So one of many highest GWP gases, as an illustration, can be the sulfur hexafluoride, so SF6. This has a GWP worth of 25,200 kilograms of CO2 equal. So that actually implies that it has over 25,000 occasions extra damaging results to the local weather in comparison with a CO2, so the equal CO2 molecule. So that is extraordinarily excessive. However there’s additionally others like NF4 that— these even have over 1,000 occasions extra damaging to the local weather than CO2. Nonetheless, they are often abated. So in these abatement techniques, you’ll be able to destroy them and so they’re now not being launched.
There are additionally efforts going into changing excessive GWP gases reminiscent of these that I’ve talked about to make use of alternate options which have a decrease GWP worth. Nonetheless, that is going to take loads of course of improvement and loads of effort to enter altering these course of flows to adapt to those new alternate options. And this can then be a gradual adoption into the high-volume fabs as a result of, as we all know, this business is kind of inflexible to any adjustments that you simply recommend. So yeah, it is going to be a gradual adoption if there are any alternate options. And for the meantime, efficient abatement can destroy quite a bit. However it will actually be having to make use of and actually have these abatement techniques on these high-impact course of areas.
Moore: As Moore’s Legislation continues, every step or manufacturing node might need a special carbon footprint. What have been a few of the huge traits your analysis revealed relating to that?
Boakes: So in our mannequin, we’ve assumed a continuing fab operation situation, and because of this we’ve assumed the identical abatement techniques, the identical electrical carbon intensities, for the entire completely different expertise nodes, which– yeah. So we see that there’s a normal enhance in complete emissions below these assumptions, and we double in complete local weather influence from N28 to A14. So once we evolve in that expertise node, we do see it doubling between N28 and A14. And this may be attributed to the elevated course of complexity in addition to the elevated variety of steps, in course of steps, in addition to the completely different chemistries getting used, completely different supplies which can be being embedded within the chips. This all contributes to it. So usually, there is a rise due to the method complexities that’s required to actually attain these aggressive pitches within the extra superior expertise nodes.
Moore: I see. Okay. In order issues are progressing, they’re additionally sort of getting worse in some methods. Is there something—?
Boakes: Yeah.
Moore: Is that this inevitable, or is there—?
Boakes: [laughter] Yeah. If you happen to make issues extra sophisticated, it is going to in all probability take extra vitality and extra supplies to do it. Additionally, if you make issues smaller, it’s worthwhile to change your processes and use– yeah, as an illustration, with interconnect metals, we’ve actually reached the bodily limits generally as a result of it’s gotten so small that the bodily limits of actually conventional metals like copper or tungsten has been reached. And now they’re in search of new alternate options like ruthenium, yeah, or platinum. Several types of metals which– once more, if it’s a platinum group metallic, after all it’s going to have the next embedded influence. So once we hit these limits, bodily limits or limits to the present expertise and we have to change it in a method that makes it extra sophisticated, extra energy-intensive— once more, the transfer to EUV. EUV is a particularly energy-intensive software in comparison with DUV.
However an attention-grabbing level there on the EUV subject can be that it’s actually necessary to maintain this holistic view as a result of though transferring from a DUV software to an EUV software, it has a big leap in vitality depth per kilowatt hour. The facility depth of the software is way larger. Nonetheless, you’re in a position to cut back the variety of complete steps to realize a sure deposition or edge. So that you’re in a position to total cut back your emissions, otherwise you’re in a position to cut back your vitality depth of the method circulate. So though we make all these adjustments and we would assume, “Oh, that’s a really highly effective software,” it might go and reduce down on course of steps within the holistic view. So it’s all the time good to maintain a sort of life cycle perspective to have the ability to see, “Okay, if I implement this software, it does have the next energy depth, however I can cut back half of the variety of steps to realize the identical outcome. So it’s total higher. So it’s all the time good to maintain that sort of holistic view once we’re doing any kind of sustainability evaluation.
Moore: Oh, that’s attention-grabbing. That’s attention-grabbing. So that you additionally checked out— as form of the nodes get extra superior and processes get extra complicated. What did that do to water consumption?
Boakes: Additionally, so once more, the variety of steps in the same sense. If you happen to’re rising your variety of course of steps, there can be a rise within the variety of these moist clear steps as properly which can be usually the high-water-consumption steps. So in case you have an elevated variety of these specific course of steps, then you definitely’re going to have the next water consumption ultimately. So it’s simply based mostly on the variety of steps and the complexity of the method as we advance into the extra superior expertise nodes.
Moore: Okay. So it feels like complexity is sort of king on this subject.
Boakes: Yeah.
Moore: What ought to the business be specializing in most to realize its carbon objectives going ahead?
Boakes: Yeah. So I believe to begin off, it’s worthwhile to consider the most important contributors and prioritize these. So after all, for those who’re wanting on the complete influence and we’re a system that doesn’t have efficient abatement, then after all, direct emissions can be the very first thing that you simply wish to attempt to give attention to and lowering, as they’d be the most important contributors. Nonetheless, when you begin transferring right into a system which already has efficient abatement, then your subsequent goal can be to decarbonize your electrical energy manufacturing, go for a lower-carbon-intensity electrical energy supplier, so that you’re transferring extra in the direction of inexperienced vitality.
And on the similar time, you’d additionally wish to attempt to goal your high-impact worth chain. So your supplies and vitality which can be coming into the fab, it’s worthwhile to take a look at those which can be probably the most extremely impacting after which attempt to discover a option to discover a supplier that does a sort of decarbonized model of the identical materials or attempt to design a method the place you don’t want that sure materials. So not essentially that it must be achieved in a sequential order. After all, you are able to do all of it in parallel. It might be higher. So it doesn’t should be one, two, three, however the concept and the prioritizing comes from focusing on the most important contributors. And that might be direct emissions, decarbonizing your electrical energy manufacturing, after which your provide chain and searching into these high-impact supplies.
Moore: Okay. And as a researcher, I’m certain there’s information you’d like to have that you simply in all probability don’t have. What might business do higher about offering that sort of information to make these fashions work?
Boakes: So for lots of our loads of our scope three, in order that upstream, that cradle-to-fab, let’s name it— these impacts. We’ve had to make use of quite a bit— we needed to rely quite a bit on life cycle evaluation literature or life cycle evaluation databases, which can be found by buying, or generally for those who’re fortunate, you’ve a free database. So I might say– and that’s additionally as a result of my function in my analysis group is extra that LCA and upstream supplies and quantifying the environmental influence of that. So from my perspective, I actually assume that this business must work on offering information by the provision chain, which is standardized in a method that individuals can perceive, which is product-specific in order that we are able to actually allocate embedded influence to a particular product and multiply that by then by our stock, which now we have information on. So for me, it’s actually having a standardized method of speaking sustainability influence of manufacturing, upstream manufacturing, all through the provision chain. Not solely tier one, however all the way in which as much as the cradle, the start of the worth chain. So that is something– and I do know it’s evolving and it is going to be gradual, and it does want loads of cooperation. However I do assume that that might be very, very helpful for actually making our work extra life like, extra consultant. After which folks can depend on it higher once they begin utilizing our information of their product carbon footprints, as an illustration.
Moore: Okay. And talking of form of your work, are you able to inform me what imec.netzero is and the way that works?
Boakes: Yeah. It is a net app that’s been developed in our program, so the SSTS program at IMEC. And this net app is a method for folks to work together with the mannequin that we’ve been constructing, the LCA mannequin. So it’s based mostly on life cycle evaluation, and it’s actually what we’ve been speaking about with this cradle-to-gate mannequin of the IC-chip-manufacturing course of. It tries to mannequin a generic fab. So we don’t essentially level to any particular fab or course of circulate from a sure firm. However we attempt to make a really generic business common that individuals can use to estimate and get a extra life like view on the fashionable IC chip. As a result of we seen that, in literature and what’s out there in LCA databases, the semiconductor information is extraordinarily previous, and we all know that this business strikes in a short time. So there’s a large hole between what’s occurring now and what’s going into your telephones and what’s going into the computer systems and the LCA information that’s out there to attempt to quantify that from a sustainability perspective. So imec.netzero, we work with all of— we benefit from being linked with the business and now a place in IMEC, and now we have a view on these extra superior expertise nodes.
So not solely do now we have fashions for the nodes which can be being generated and produced immediately, however we additionally predict the longer term nodes. And now we have fashions to foretell what’s going to occur in 5 years’ time, in 10 years’ time. So it’s a very highly effective software, and it’s out there publicly. We’ve a public model, which is a limited– it has restricted performance compared to this system associate model. So we work with our program companions who’ve entry to a way more sophisticated and, yeah, deep method of utilizing the net app, in addition to the opposite work that we do in our program. And our program companions additionally contribute information to the mannequin, and we’re continually evolving the mannequin to enhance all the time. In order that’s a little bit of an summary.
Moore: Cool. Cool. Thanks very a lot, Lizzie. I’ve been talking to Lizzie Boakes, a life cycle analyst within the Sustainable Semiconductor Applied sciences and Techniques Program at IMEC, the Belgium-based nanotech analysis group. Thanks once more, Lizzie. This has been unbelievable.