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 min read

The Flex Factor with... Charlotte

semiconductor industry scheduling wafer fabs optimization

This month on The Flex Factor, we get to know our Senior People & Talent Partner, Charlotte Conway! Find out a little more about her and how she creates a supportive environment that helps our whole team to thrive.

Tell us what you do at Flexciton?

I work across both the People and Talent function as a Senior People & Talent Partner. I help Flexciton to find, attract and recruit top talent, and am responsible for engaging, supporting and developing our employees.

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

There is no such thing as a typical day in a startup! However, my day is often split 80% on the people side and 20% on talent. I like to start my day with any admin tasks or reply to any slack messages that might have come through. I then create a to-do list for what I plan to do that day. This can be dealing with employee queries, or business partnering with managers to check in on any people related matters. During busier periods I will often be taking a hands-on approach to hiring, sourcing and speaking to candidates as well as setting up our talent processes and looking at our employer branding strategy to help us to attract the best talent. As a startup there are also lots of projects to get involved in across all of HR (e.g. performance management, L&D) so a lot of my day may involve working on improving our people and talent processes... or implementing new processes!  

What do you enjoy most about your role?

What I enjoy most about my role is getting to work closely with our people (I guess it’s in the name, ‘people partner', right?). For me, the important part of being a ‘people’ partner is creating an environment where people feel heard, supported, and empowered to bring their best selves to work. Being able to have a small part in ensuring employees have all of the above is incredibly rewarding and fulfilling.

What's a quote that you live by?

“I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel.”

― Maya Angelou

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

Exciting, dynamic and FUN.

If you could give one piece of career advice to someone, what would it be?

Never doubt yourself or let fear of failure hold you back. It’s ok to make mistakes and take risks! It’s better to look back and never have that feeling of ‘what if’ because you were too scared to take the next step.

Tell us about your best memory at Flexciton?

There are lots! However, It’s one of the many fun Flexciton socials that comes to mind - Dabbers Bingo. What better way to celebrate with your colleagues than with some good, old fashioned competition. There was dancing, music and of course bingo. This was then followed by a late night showing of Shrek in the office, and a very patient colleague (thanks Jannik) failing miserably to teach me how to ride a bike…I blame the one too many glasses of prosecco!

Interested in working at Flexciton? Head over to our careers page to to check what vacancies we currently have available and learn a little more about us whilst you're there.

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optimization scheduling engineer wafer fabs
Read time
 min read
Culture
The Flex Factor with... James

Meet James Adamson, one of our senior optimization engineers here at Flexciton. Many, many moons ago he was an aspirant farmer, now he’s designing and improving our scheduling algorithms.

Meet James Adamson, one of our senior optimization engineers here at Flexciton. Many, many moons ago he was an aspirant farmer, now he’s designing and improving our scheduling algorithms. 

Tell us what you do at Flexciton?

I’m an Optimization Engineer, which essentially means I focus on designing and improving our scheduling algorithms, while also implementing and maintaining them in production code. I also have a technical lead role for one of our customers, so I spend some time understanding their requirements in detail and thinking about how to expand the product or customise it to meet their individual needs.  

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

In my engineering team we kick things off with a stand-up to agree on priorities for the day and discuss any issues that need attention. My day would then typically be a mix of drinking coffee, getting stuck into writing code for some new functionality, and having design discussions with other members of the team to keep us aligned technically. 

What do you enjoy most about your role?

I would say the opportunity to combine two things: working on one of the most challenging optimisation problems out there; and the ability to actually have an impact, for example through getting my code into production or making and influencing key design decisions.

If you could give one piece of advice to someone, what would it be? 

I would maybe suggest they seek advice from better places… but no, I think it’s important to always be thinking about what it is you want, and to think several steps ahead. It’s all too easy to get stuck doing something you don’t enjoy.

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

Interesting, challenging, impactful.

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

I used to want to be a farmer… so provided I could pick a day with decent weather then sure why not give that a go for day. I reckon it’s much harder work than the idea I used to have of chilling on a combine harvester though…

Tell us about your best memory at Flexciton?

There’s a whole bunch of memories from our team trips, most recently to Albufeira in Portugal where some people really shone with their dance moves. I will avoid naming names.

innovations in wafer fab production scheduling using optimization and heuristics
Read time
 min read
Technical
Scheduling Innovations: Academic Research and its Adoption in the Semiconductor Industry

This article focuses on innovations in scheduling: algorithms which assign lots to machines, decide in which order they should run, and ensure any required secondary resources are available.

Introduction

The first integrated circuits were invented by Texas Instruments and Fairchild Semiconductor in 1959. Today, semiconductor manufacturing is a $600 billion dollar industry and microchips are ubiquitous and impact our lives in ever increasing ways. To achieve such astonishing growth, academics and industry have had to constantly innovate, researching new production technologies. While much has been said about Moore's law and the push towards higher and higher transistor densities, the innovations made in how the billion dollar factories producing these chips are run have received less attention. This article focuses on innovations in scheduling: algorithms which assign lots to machines, decide in which order they should run, and ensure any required secondary resources (e.g. reticles) are available. These decisions can significantly impact the throughput and efficiency of wafer fabs.

Many innovative technologies in scheduling were first proposed by researchers and have, over time, been adapted in manufacturing. They include:

  • Dispatching: rule-based systems for deciding which lot to run next on a tool 
  • Optimization-based scheduling: mathematical techniques like mixed integer programming and constraint programming which can generate optimal machine assignments, sequencing, and more for entire toolsets or areas of the fab, improving fab-wide objectives like cycle-time or cost
  • Simulation: computer models of the manufacturing process which are often used to run what-if analysis, evaluate performance, and aid decision making

From dispatching to mathematical programming

Early academic research on dispatching rules dates back to the 1980s. Authors at the time already highlighted the significant impact scheduling can have on semiconductor manufacturing. They experimented with different types of dispatching rules, ranging from simple first-in-first-out (FIFO) rules to more bespoke rules focused on particular bottleneck tools. Over time, dispatching rules have evolved from fairly simple to increasingly complex. Rule-based dispatching systems quickly became the state-of-the-art in the industry and continue to be popular for several reasons: they can be intuitive and easy to implement, yet allow covering varying requirements. There are, however, also many situations in which dispatching rules may perform poorly: they have no foresight and generally look only at a single tool and therefore often struggle with load balancing between tools. They also struggle with more advanced constraints such as time constraints or auxiliary resources, e.g. reticles in photolithography. More generally, dispatching systems are a mature technology that has been pushed to its limits and is unlikely to lead to significant increases in productivity and yields.

For these reasons, focus has shifted over time to alternative technologies, especially deterministic scheduling based on mixed-integer programming or constraint programming. In the academic literature, these approaches start to increasingly show up around the 1990s. Early contributions focused on analysing the complexity of the wafer fab scheduling problem and solved the resulting optimization problem using heuristic techniques, but slowly moved towards rigorously scheduling single machines, tackling one particular aspect of the problem at a time. Due to the limited scope deterministic techniques could initially tackle, their adoption in industry lagged behind the academic discussion. 

From single machines to fab-wide scheduling

The last twenty years have seen deterministic scheduling techniques mature and schedule larger and more complex fab areas. In the academic literature, authors moved from focusing on single (batching) tools, to entire toolsets or larger areas of the fab including re-entrant flows. They also started including more and more operational constraints such as sequence-dependent setup and processing times, time constraints, or secondary resources such as reticles. In order to achieve this increase in scale and complexity, researchers have applied a large number of optimization techniques, and often combined rigorous mathematical programming methods with heuristic approaches.  Some have used general purpose meta-heuristics, such as genetic algorithms or simulated annealing, while others have developed bespoke heuristics for fab scheduling, such as the shifting bottleneck heuristic

As the size of problems optimization-based scheduling techniques could solve grew, the industry started to explore how to adopt these methods in practice. For example, in 2006, IBM announced that it had successfully used a combination of mixed-integer programming and constraint programming to schedule an area of a fab with up to 500 lot-steps and that this had led to a significant reduction in cycle time. Our own technology at Flexciton leverages mathematical optimization and smart decomposition, combined with modern cloud computing, to efficiently schedule entire fabs. One key advantage of using cloud technology is the ability to access huge amounts of computational power. It allows to break down complicated problems and deliver accurate schedules every few minutes, as well as the ability to adapt the solution strategy to the complexity at hand. Additionally, it enables responsive adjustments, as events unravel in real-time, allowing for a truly dynamic approach to scheduling.

Optimization-based scheduling’s trajectory from an academic niche to a high-impact technology has partially been accelerated by two major trends:

The process has been accompanied by considerable improvements in productivity, as scheduling is able to overcome many of the downsides of dispatching: it can look ahead in time, balance WIP across tools, and improve fab-wide objectives such as cost or cycle-time. A major advantage of scheduling is that it can both increase yields when demand is high and reduce cost when demand is low. 

When in doubt, simulate.

A discussion of scheduling in wafer fabs would not be complete without a word on simulation models. Simulation models are technically not scheduling algorithms - they require dispatching rules or deterministic scheduling inside them to decide machine assignment and sequencing. But they have been used to evaluate and compare different scheduling approaches from the very beginning. They were also quickly adopted by industry and have, for example, been used by STMicroelectronics to re-prioritise lots and by Infineon to help identify better dispatching rules. The development of highly reliable simulation models could greatly increase their use for performance evaluation and scheduling.

The future

More reliable simulation models are also important in light of recent trends in academic literature, which may provide a glimpse into the future of wafer fab scheduling. Rigid dispatching rules that need to be (re)tuned frequently may soon be replaced by deep reinforcement learning agents which learn dispatching rules that improve overall fab objectives. In some studies, such systems have been shown to perform as well as dispatching systems based on expert knowledge. If and when the industry adopts such techniques on a large scale remains to be seen. Since they require accurate simulation models as training environments, they can be extremely computationally intensive, and their adoption will largely depend on the development of faster training and simulation models. The combination of self-learning dispatching systems, and comprehensive, scalable scheduling models may well hold the key to unlocking unprecedented improvements in fab productivity. 

Flexciton aspires to be the key enabler in this transition, bringing state-of-the-art scheduling technology to the shop floor in a modern, sophisticated, and user-friendly platform unlike anything else on the market. Despite the enormous challenges that come with the scale of this endeavour, the initial results are very encouraging; cloud-based optimization solutions can indeed bring a step change to streamlining wafer fab scheduling while delivering consistent efficiency gains. 

flex factor get to know sudesh flexciton
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 min read
Culture
The Flex Factor with... Sudesh

Say hello to Sudesh Lutchman; senior back end engineer, delivery manager for the Taiichi team here at Flexciton and aspiring jet pilot.

Say hello to Sudesh Lutchman; senior back end engineer, delivery manager for the Taiichi team here at Flexciton and aspiring jet pilot.

Tell us what you do at Flexciton?

I’m a delivery manager / backend engineer for the Taiichi Team - I help plan the team’s work and coordinate its delivery within the team.

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

A typical day for me at Flexciton is split into two main responsibilities. The first bit is working with product and other delivery managers to ensure that we are building the right things and that we are building them at the right time. The second responsibility is ensuring that Taiichi runs smoothly. This means helping teammates with tickets and importantly trying to identify and remove any impediments that the team might be having.

What do you enjoy most about your role?

I enjoy the challenge. At Flexciton we are solving a very complex problem. Not only is the core problem difficult to solve but managing the software development of these solutions is equally complicated. As a delivery manager and an engineer I get the pleasure of trying to simplify both.

If you could give one piece of advice to someone, what would it be?

Start simple and do not be afraid to “fail.” This has definitely helped me have some amazing experiences and learn valuable lessons along the way.

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

Talented people. Exciting.

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

Jet pilot - hopefully the skills transfer during this job swap and I get to zip over entire continents in a few hours. If the skills don’t transfer… I’ll do my best.

Tell us about your best memory at Flexciton?

Channy (Head of Operations) getting my start date wrong and the funny conversation that followed. Channy was expecting me to be in the office full time (before my start date) and I was regretting telling them that I wasn’t working at the moment. This led to some really confused looks being shared between us.

Interested in working at Flexciton? Head over to our careers page to to check what vacancies we currently have available and learn a little more about us whilst you're there.