On this month's edition of The Flex Factor, we're introducing Amar. Solutions engineer by day and the front man of Flexciton's band by night, find out a bit more about him and what he does for the team.‍

Tell us what you do at Flexciton?

It would be easier to say what I don’t do! Being on the Customer Team means I get involved with all aspects of the business, from explaining the technicalities of the Flexciton software in the very first call with a new client to working on new features that need to be implemented for a live trial in a wafer fab. Right now I’m working on a dynamic capacity model to simulate a client’s wafer fab under different scenarios in order to measure the impact of changing tool availability. 

What does a typical day look like for you at Flexciton?

I’ll usually have multiple projects at once, so sometimes I’ll be running code overnight to be more efficient. This means I first check on the results of whatever I was running and figure out what needs to be changed. The next thing I tend to do is work on the other projects I’m on, like PoCs or Live Pilots. For PoCs this might be working on modelling new tool constraints and running simulations, and for Pilots we might need to add a new feature to accommodate a fab’s specific needs. Oftentimes I’ll also have client calls so I can show them what I’ve done and explain how we can help their fab improve KPIs.

What do you enjoy most about your role?

The variety is great, no two days are the same. I love being able to talk to new clients and figure out how best to apply the Flexciton solution to their needs. Most clients have vastly different KPI goals for their fabs, and so it’s a super interesting challenge to work out how Flexciton can be set up to run their fab optimally.

What’s one thing you’re learning now or learned recently?

I’ve been teaching myself to play the Guitar for the past few years. The Flexciton team has started their own mini band, and it’s been super fun playing with such talented musicians. I feel like I’m learning at a much faster rate thanks to the impromptu jam sessions.

If you could swap jobs with anyone for one day, who would it be and why?

I’d love to work in sports analytics. I’ve been a football fan my whole life, and I reckon if I had the data I’d be able to figure out why my beloved Liverpool FC are performing so poorly this season.

Tell us about your best memory at Flexciton?

I think I’ll have to copy everyone else and say the team trip last year, being able to show off my football skills in the rain on the beach in Albufeira was great, even if I did get stuck in the sand a few times.

‍

Interested in joining the Flexciton team? Take a look at our current vacancies to see if there's a role fit for you.

The semiconductor industry needs to become more sustainable in a world of increasing demand – optimization holds the key.

An energy-intensive industry 

Over the past decade, industries worldwide have had to tackle the issue of sustainability as a matter of increasing urgency, with the need to mitigate greenhouse gas emissions becoming a major factor in companies’ operations and processes. For many, this has been a difficult accommodation to make, because it has forced them to change the way they work. On the other hand, addressing the climate crisis has acted as a catalyst for the transition to more innovative and efficient methods of production and manufacture.

The semiconductor industry is at the heart of our modern technological society, and as recent supply chain issues have demonstrated, any slowdown in production has a significant knock-on effect on multiple other sectors. Given its centrality, and the need to maintain output, sustainability hasn’t always been as high on the agenda of chip companies as it should have been. However, ignoring the serious environmental impact that semiconductor industry has on the world around it is no longer tenable.

According to McKinsey, “large semiconductor fabs use as much as 100 megawatt-hours of energy each hour, which is more than many automotive plants or oil refineries do.” They also point out that an average fab will use as much power in a year as 50,000 homes – that’s enough electricity to run a small town. And as the demand for semiconductors continues to grow, and the production process becomes ever more sophisticated, on its current trajectory, the industry’s energy usage is only set to increase.

Electricity production is of course a major source of CO₂ emissions, with the majority of power stations still fuelled by hydrocarbons such as coal and gas. It’s an inescapable fact that using more energy means emitting more greenhouse gases – so reducing energy consumption is an obvious way for the semiconductor industry to improve its environmental footprint. But given the demand outlined above, how is this realistically possible?

KPIs vs the green agenda

If we look at where the energy in fabs is actually being used, a solution becomes clearer. McKinsey calculates that approximately 55% of energy consumption is generated by running tools. Given that many of the machines on a fab’s production line are in use 24/7, this perhaps isn’t that surprising. And as I noted earlier, chip companies aren’t about to reduce this level of operation just to become more environmentally-friendly – for both them and other industries, the stakes are too high to do anything that would threaten production.

This is reflected in the KPIs that fabs work to, which are primarily based on cycle time, throughput and yield – energy consumption has historically been very much a secondary consideration. However, production doesn’t completely exist in a bubble, and as with any company, the bottom line is the ultimate driver of operations. Cost reduction is just as important as revenue generation. McKinsey notes that, depending on local electricity tariffs, energy consumption can account for up to 30% of a fab’s operating costs. And with the price of energy continuing to rocket, that figure is almost certain to increase.

So given that energy is a factor that affects both production costs and sustainability, reducing consumption is edging its way up the fab’s table of priorities. Yet what if you could address both those primary KPIs and the need to be greener at the same time? 

Optimizing primary goals and energy consumption

Optimization technology is the key. It’s a point I keep returning to, but if chip companies are to deal with the challenges that the future is sure to keep throwing at them, then they have to start adopting best-in-class smart manufacturing practices and software. 

To properly optimize the way in which the fab works, we have to first understand exactly what the state of the entire WIP is in real time. By mapping the current state of the fab’s operations, it’s possible to identify where bottlenecks are occurring due to sub-optimal scheduling. And in our experience of working with different fabs, the tools where queues usually occur are involved in the most energy-intensive stages of the production process – for example, photolithography, diffusion furnace and in the cleanroom. 

Using optimization software to reduce bottlenecks by improving how wafers move through energy-intensive tools, the fab’s primary KPIs can be met and energy consumption at these tools can be reduced. For example, doing more moves with fewer tools at the photo stage means that it’s possible for some tools to be left idle. Or doing the same moves but with fewer batches at the furnace stage means fewer energy-intensive furnace runs. 

At the tail end of last year, I gave a presentation at the Smart & Green Manufacturing Summit, as part of Semicon Europa 2022, that outlined how our scheduling optimization software has already achieved these goals in the real world.

Optimization technology can also be used to directly control the energy consumption of less busy tools as well. As long as those areas that are prone to bottlenecks are running efficiently, and all primary KPIs are being met, tools in other areas can be optimized specifically for energy conservation – for instance, powered down because the scheduling technology has identified that they aren’t required or don’t have to be operated at their maximum rate.

Taking sustainability seriously

Most of the larger semiconductor companies are looking at ways to be greener and meet net zero goals, although carbon offsetting is currently playing more of a role than making manufacturing processes more energy efficient. However, some companies are addressing the issue head-on and looking at ways to control their fabs’ energy use – for example, Flexciton, Imperial College London and the Technical University of Munich are currently working together on a project to map Infineon’s energy consumption, with the aim to better understand how smarter decisions can help the company reduce its carbon emissions.

The demand for semiconductors is only going to grow in the decades ahead, but a reckoning over the industry’s attitude to sustainability will be reached much sooner than that unless energy reduction becomes one of its key priorities. Yet by working smarter and re-evaluating their production processes, it’s absolutely possible for companies to improve throughput and yield while at the same time being more energy efficient.
‍

Author: Jamie Potter, CEO and Cofounder

Chipmakers will encounter major challenges before the end of the decade in their quest to achieve stringent emissions goals. Achieving these targets will require a concerted effort from the industry to explore new and innovative methods of reducing their energy consumption and adopting cleaner energy sources.

In light of this, we are working together with Thorsten Greil from the Technical University of Munich, Nilay Shah from Imperial College London, and Hans Ehm from Infineon Technologies on an energy efficiency initiative to explore innovative approaches for reducing the carbon impact of the semiconductor sector. The objective of this undertaking is to make a valuable contribution towards realising a more environmentally-friendly future.

One low-cost opportunity to reduce emissions that does not require drastic capital investment is operational efficiency, where reduction of the energy consumption in production is considered as top priority. Together, we are inviting qualified students from The Technical University of Munich and Imperial College London to participate in the project and complete their master’s thesis on the following topic: Global virtual factory simulation for energy efficiency. Our findings will be presented at the Winter Simulation Conference 2023. 

Project Objective

A hypothesis is that the energy efficiency – and subsequently the gas emissions – of a wafer fab can be reduced through improvements in operational efficiency, such as production scheduling. Previous studies have considered chemical alternatives, where Infineon investigated the use of alternate gases with less impact on the climate. Similarly, potentially significant savings can also be made in smarter and more environmentally friendly daily operational decisions. 

We want to discover what operational decisions could be taken at fab level to reduce CO2 emissions, without drastic investment or damaging productivity. For example, how can we incorporate CO2 emissions targets into production scheduling? And whether or not it's possible to reduce CO2 emissions whilst improving cycle time. 

Procedure

The solution approach to the above objective will be supported by the following methods:

• Familiarisation with semiconductor manufacturing including cleanroom and facility environment characteristics with a focus on energy consumption and operational decisions.

• Literature review in the field of energy efficiency and scheduling to present the current state.
• Embedding energy related aspects in the fab simulator tool developed by Flexciton based on energy emission information provided by Infineon.
• Investigation of smarter coordinated operational decisions in the fab to reduce carbon emission.

Say hello to Jamie, one of Flexciton's frontend developers. From watering his cactus to perfecting the user experience of our application, find out what he does during his day-to-day in this month's edition of The Flex Factor.‍

Tell us what you do at Flexciton?

At Flexciton, I have a few different roles. My main role is as a frontend developer, which means I work on creating and improving the user interface of the app. But I also have other responsibilities - I lead the frontend engineering practice, and I'm in charge of guiding discussions and decisions about the frontend architecture. It keeps me busy, but I enjoy the variety!

What does a typical day look like for you at Flexciton?

A typical day for me at Flexciton starts off with some personal tasks - I check on my trusty cactus (Mr Prickles) and give him some water. After that, I open up my personal Trello board and plan out my day, which usually involves working on engineering tasks or frontend related work.

Next up is the daily stand up meeting, where I update the team on what I've accomplished and what I plan to work on for the rest of the day. Then it's time to dive into work - if I'm working on an engineering task, that usually means writing some code and asking for help from resources like StackOverflow or ChatGPT. I like to listen to some ambient and melodic tunes while I work.

If it's a practice day, I'll probably be working on tickets to address existing tech debt or putting together plans for the UI architecture. Around lunchtime, I take a break and grab some food - on Tuesdays, we have a team lunch that gives us a chance to chat with other members of Flexciton outside of our immediate team. After lunch, it's back to work until it's time to call it a day.

What do you enjoy most about your role?

What I enjoy most about my role at Flexciton is the variety of tasks and responsibilities that come with being a frontend developer and leading the frontend engineering practice. I love delivering features that provide real value to the users of our app, and there's nothing better than seeing someone using a feature I've helped build. The idea of making a user's experience even just a tiny bit better is highly motivating.

On a daily basis, I get to work on both technical and creative aspects of the app - whether it's writing code for engineering tickets, collaborating on designs, or planning out the UI architecture. I find it really satisfying to see the tangible results of my work and how it contributes to the overall success of the company.

Additionally, being part of a team that is collaborative, supportive, and always striving for improvement makes my job even more enjoyable. I appreciate that I have the opportunity to learn from my colleagues and contribute my own ideas to help move the company forward. Overall, the combination of technical challenges, a positive team environment, and the ability to make a real impact on our users is what makes me look forward to coming to work every day.

‍If you could do it all over again, would you pursue your same career?

Absolutely, I would pursue the same career again without hesitation. Before transitioning to frontend development, I worked as an electrician for five years. Although I gained valuable experience and skills during that time, I knew that it wasn't the right long-term career path for me.

Switching to frontend development was a challenging but rewarding decision. I've been able to build upon my previous technical knowledge and apply it in new and exciting ways. I feel incredibly lucky to have found a career that I truly enjoy, and I never take that for granted.

Being a frontend developer allows me to combine my technical skills with my creativity and problem-solving abilities. I find the work to be constantly engaging, and I'm always learning new things. The fact that I'm able to contribute to the success of a company and make a positive impact on its users is incredibly fulfilling.

I know that not everyone has the opportunity to pursue a career they enjoy, so I feel grateful every day for the path that led me to frontend development. Looking back, I can confidently say that I made the right decision, and I'm excited to see where this career will take me in the future.

‍If you could summarise working at Flexciton in 3 words, what would they be?

Rewarding, challenging, fun

Tell us about your best memory at Flexciton?

My first day at Flexciton is definitely one of my fondest memories. Starting a new job can be daunting, but I was immediately struck by the friendly and welcoming atmosphere in the office. My colleagues went out of their way to make me feel comfortable and part of the team from the get-go. I knew from that first day that I had made the right choice in joining this company.

Since then, I've had the opportunity to work on some truly exciting projects and collaborate with some incredibly talented people. Every day presents new challenges and opportunities for growth, and I'm constantly motivated to improve and learn.

But it's not all work and no play at Flexciton. One of the highlights of the year for me is our company trips. After working hard all year, it's a much-needed break to spend some quality time with my colleagues and enjoy some downtime. It's always a great bonding experience, and I come back feeling re-energized and ready to tackle whatever challenges lie ahead.

Overall, I feel incredibly fortunate to be part of such a supportive and dynamic team at Flexciton. From my first day to now, it's been a truly memorable and rewarding journey, and I can't wait to see what the future holds.

‍

One of the consequences of the pandemic has been an incentive to deglobalise, as regions suffered from the issues with supply chains and geopolitical dependencies. Significant delivery issues in the chip industry – and in particular wafer manufacturing – have had a negative impact on the global economy. However, onshoring this high technology industry will also bring its own challenges. Expertise and cost efficiency to name a couple. Zooming in a bit closer on so-called wafer fabs, we can distinguish two types of factories. The legacy and smaller fabs serving niche markets with older technology nodes, and the cutting-edge giga-factories, recently built or in the making. Both types have different problems to tackle, but one key component of their roadmap could be surprisingly similar.

The newest fabs have well integrated automated systems, but operating them efficiently on such a scale is a challenge of its own. The older factories have the downside of being less automated but they realise the need to become more efficient in energy consumption, labour cost and capacity utilisation. In both situations, digital transformation is coming to the rescue. Industry 4.0 is no longer a buzzword, it has become a matter of regional technological sovereignty. 

The fundamental building block of Industry 4.0 is data; an asset which is present in abundance in wafer fabs. So what is preventing these factories from levelling up? The answer is simple, the solution is not: complexity. It’s an inherent part of wafer manufacturing, stemming from; increasingly high numbers of process steps, job shop factory types, re-entrant flows, product diversity, sensitivity to quality issues and so on. 

The problem with complex systems is that there’s so much variability and interaction, it's hard to get actionable insights from data. Instead of accepting the stochastic and complex nature of the fab, factories can better control it by using advanced production scheduling to understand in which order lots get processed, on which tool and – the most important difference when compared with common rules-based approaches – when they get processed. To begin, this can be employed in certain bottleneck areas and then once you do it for the entire factory, you get a holistic picture of what is going to happen. Sounds great, doesn’t it? But how exactly will this benefit your fab? To explain, let’s place production scheduling in a couple of recognisable use cases. 

‍

1. Lot-Tool Assignments

Wafer manufacturing has complicated recipe-tool qualification matrices within a group of tools that perform similar processes. The weaker tools can process fewer recipes than the stronger ones. We want to avoid stronger tools “stealing” lots away from the weaker tools, because it leaves fewer lots for the weaker tools to process, therefore wasting capacity. The same is true for faster and slower tools: while faster tools are preferred, pushing all the WIP through the faster tools leaves the slower tools under utilised. Advanced schedulers allow for better anticipation of incoming WIP and superior use of available capacity for weak and slow tools. The bigger and more complex the matrix grows, the harder it is to find the optimal processing of WIP. On top of the scheduling itself, mathematical programming helps to optimize lot-to-tool assignments over time. This results in a capacity booster, similar to putting a turbocharger on an engine: it’s the same engine, but with more power.

2. Reducing Timelink Violations

Process steps with timelinks are common in wafer manufacturing to control the maximum amount of time a wafer spends between two or more process steps. If a timelink is violated, the wafer requires rework – or worse still, scrappage. A system that avoids timelink violations requires the ability to intelligently plan into the future. And that’s exactly what an advanced scheduler does. It has been proven to drastically reduce timelink violations, even in the most complex of scenarios. 

3. Improving Batching Efficiency 

Batching is a complex decision making process since it involves an estimate of lot arrivals and how waiting longer trades off with running smaller batches. Predicting lot arrivals is difficult in such a complex environment, and trading off wait time against batch efficiency is even harder because the costs and gains are not always clear. Determining and automating this process is well within an advanced scheduler’s remit. Once the algorithm is tuned, it makes the most efficient decision, and perhaps even more importantly: it generates consistent output. 

4. Optimizing Changeover Decisions 

Another use case related to the problem of lot arrivals is the problem of changeover decisions. One toolset with different machine setups can serve multiple different toolsets down the line. A bit like a waiter in a restaurant serving multiple tables. Waiters have to make sure no table is without food or drink, and to do that, they visit the tables regularly to ask for any orders. But for machines, you can’t switch the setup too often because it only increases non-productive time. Preferably, you also plan setup changeovers at a time when planned or predicted downtime for the machine occurs, to reduce downtime variability. To put it simply, it’s a decision on when to switch over from the type A process to the type B process on a tool. An advanced scheduler can solve that equation, finding the optimal point in time. Schedulers are better at this than human reasoning or rule-based logic, as solving to a time dimension is what they are designed for.

5. Flow Control and Line Balance

Line balancing is – even for experienced manufacturing engineers – difficult to grasp. One can intuitively understand what it means, but how do you define “balanced” in the first place? Even if you can, it is absolutely beyond the capabilities of a human brain to manually and continuously make decisions that control it. And once it’s out of balance, to recover it. Again, considering the time dimension is a crucial aspect of what advanced schedulers offer, which enables them to recover faster from unforeseen circumstances and maintain better risk-control for generating continuous output.

6. Operator Task Lists

As opposed to dispatch lists that only tell the order in which to process lots, advanced schedulers can also tell when a lot is supposed to start and finish processing on a tool. Combine that information with which operators are serving which tools, and you can move away from tool-centric dispatch lists towards operator-centric task lists. With a handheld device, that could even allow you to send push notifications when urgent intervention is needed. It can reduce idle time on tools that have no available operator. Even more so, it can allow for an entire rethink of the workflows operators are used to. 

‍

‍

So far in this blog, we’ve focused on scheduling use cases where lots are scheduled on tools, leading to higher throughput on tools, toolsets or the entire factory. All these use cases can also be addressed by improving some rule-based dispatching strategies, but what advanced scheduling offers is the ability to optimize for future decisions rather than just real-time. With that comes better visibility on what will happen in the factory, and it also leaves opportunities for re-organising workflow and freeing up resources. In part 2 of this blog, we’ll begin to look at the future and what could happen when we integrate even further. Enter, Industry 5.0. 

Author: Ben Van Damme, Industrial Engineer and Business Consultant

‍

Part 2 is now live. Click to read.

‍

‍

‍Timelink constraints are one of the most complex issues to handle in fab scheduling. They define the maximum allowed time between steps in the production of a wafer. Correct scheduling of timelinks is critical to helping minimise the risks of oxidation or contamination. This can happen when a wafer is queuing outside of a tool for too long, resulting in scrappage or rework that damages profitability. Renesas Electronics asked Flexciton to see if its intelligent scheduling software could improve this aspect of scheduling in the diffusion area of its wafer fab.
‍

What makes timelink constraints very hard to schedule is their interdependence. For example, by moving from step one to step two, the wafer enters the first timelink. When moving from step two, the wafer enters a second timelink which lasts until step 4. However, there can also be a third timelink constraint – known as a nested timelink – between step three and step four which overlaps the second timelink constraint (see Fig. 1). Therefore, step three has to be scheduled in a way that allows for both the second and third timelink constraints to be adhered. This example discussed is just for a few steps but, in reality, there could be hundreds of steps and many overlapping time constraints that need to be continually considered. This creates one of the most complex scheduling problems seen in a wafer fab, and any violation of the timelinks has a negative financial impact. 

The most commonly used scheduling approach is based on heuristics, using a set of if-then operational rules that have been manually programmed and require constant maintenance. This is a relatively simplistic methodology that has hardly changed over the past two decades and thus cannot effectively solve today’s much more challenging scheduling problems. In modern day fabs, very complex, multi-dimensional problems are common on a daily basis and existing heuristic approaches don’t have the built-in intelligence to look ahead to future steps. 

Flexciton’s next-gen scheduling software is the only solution on the market that is able to do this. It pairs powerful mathematical optimisation technology with smart decomposition techniques to work out solutions with complete autonomy. It has the ability to generate an optimised production schedule within a few minutes by searching through billions of scenarios to select the best possible one. Importantly, its intelligent algorithms consider the knock-on effects that one change can have against all the other constraints in the fab – including timelinks. This repeating iterative process ensures that it is continually updating the schedule to allow for any changes in fab conditions or business objectives.

The software was run in a simulation environment that replicated the way that Flexciton’s scheduler would have run live at the Renesas fab. The results showed that a significant improvement in reducing timelink violations of 29% could be achieved.  Additional improvements would be possible of a 22% reduction in the number of batches and an 11% reduction in queue time despite these two KPIs being conflicting (see Fig. 2). This is because decreasing the number of batches naturally means increasing the number of wafers in each batch, but this increases the queue times for each batch as operators wait for new wafers to arrive at the tool before processing them together. 

Currently, most fabs have no knowledge of the arrival times for future lots so operators can sometimes wait unnecessarily to maximise a batch size, causing more wafers to queue and damaging productivity. Uniquely, the Flexciton scheduler can see how lots are moving in time and can thus optimise the trade-off between number of batches and queue time to achieve the impressive gains seen on these conflicted KPIs.  

Renesas were impressed with the simulation figures. Jay Maguire, Engineer at Renesas, commented, “Flexciton was able to show us several specific decisions we could have done differently to improve batching and cycle time. We are pursuing a live trial of the Flexciton software.”

‍

Jamie Potter, Flexciton’s co-founder and CEO, explained, “The key differentiator of our approach is that our software has the intelligence to predict what may happen in the future based on the current state of a fab (or WIP in a fab). It searches for the best solution amongst billions of possibilities to continuously keep finding the optimal schedule that meets the KPIs to maximise a fab’s productivity and profitability. Humans and heuristics just can’t do that.” 

‍