Light sensitive materials play a key role in enabling integrated chip manufacturers to create the modern day smart devices, from cell phones and computers to automotive power devices, MEMS, ASICs etc
Chidharth Krishnaraj, our next pathbreaker, works as Senior R&D Product Application Engineer at JSR Micro NV (Belgium), a company that develops high performance materials (Photoresists) for the semiconductor industry.
Chidharth talks to Shyam Krishnamurthy from The Interview Portal about his master’s thesis at KU Leuven, where he worked for a year at IMEC on the application of graphene related materials for EUV lithography.
For students, a hobby can bring happiness, but a career needs to sustain you. Please find the sweet spot where passion and purpose meet each other.
Chidharth can you share your background with our young readers?
I was born in Coonoor, Tamilnadu (Ooty). However, I rarely had the chance to “settle” in one place for more than three years. My father’s career in the army meant that we had to regularly pack our bags and find solace in a new place about once every three years. This gave me the opportunity to explore several cities and experience different cultures and diversity across India. This was both a blessing and a challenge, as I developed skills early on to adapt to new environments but on the flipside I rarely had opportunity to build long term connections. Back then, social media was much less prevalent, so staying in touch was much harder.
In terms of extra-curricular activities I was deeply fascinated by reading and playing cricket, badminton, and chess. I often spent hours in the school library looking for new books to read, both fiction and non-fiction. In school, my interests were in the field of computers, mathematics and chemistry. Whereas, biology did not appeal to me a lot. When I had the choice, in my 11th standard, I opted for the computer science stream. However, I ended up taking Biotechnology as my major during my undergraduate. This decision was made more out of the desire to attend a good college rather than a clear focus on my true interests. Looking back, it was a choice driven by immaturity. Fortunately, later on I still had the opportunity to realign my career based on my original interests in mathematics and chemistry.
What did you do for graduation/post graduation?
My undergraduate degree was in Biotechnology from Anna University. There was a funny quote in India in the 2000s: “In India, students discover what they want to do only after completing an engineering degree.” This turned out to be true in my case. I decided to focus my career in chemistry during the third year of my undergraduate degree.
This was sparked by a summer internship in materials chemistry at IIT-Bombay. This interest was further reinforced when I did a research internship in my final year at the University of Queensland, Australia. There, I worked on the development of nanoporous materials. These are sponge-like materials but with pores so small that just a single gram can have surface area equal to that of a football field.
After my internship in Australia, I was fascinated with the field of nanomaterials and I decided to further enhance my knowledge and skills in this area. This led me to Belgium where I pursued my masters in nanoscience, nanotechnology and nanoengineering at KU Leuven. Nanomaterials and Nanochemistry was my obvious choice as major within this broad field. Here I was able to do a thesis year at IMEC, Belgium on Graphene related material for EUV lithography. This laid the foundation to where I am working today.
What were some of the key influences that led you to such an offbeat, unconventional, and unique career in Deep Tech, that is, Semiconductor Physics?
After my masters, I decided to pursue a PhD in chemistry at Ghent University, Belgium. Here I worked for four years on development of nanoporous materials for energy applications. Through consistent effort, I was able to contribute to several peer-reviewed publications, achieving research outcomes that placed me ahead of many of my peers. This experience strengthened both my expertise in chemistry and my ability to tackle complex scientific challenges.
Several key influencers have been a part of my career, including professors who supervised my research during my internship in Brisbane, Australia, my research exchange in Berlin, Germany and my doctoral work in Ghent, Belgium. These professors are specialists in their respective fields and they shared not only their deep academic knowledge but also valuable insights from their professional experiences.
My mentor is a senior scientist who provided crucial support and guided me through the daily challenges of lab work.
Today, my career is a mix of my research background in polymers and my theoretical foundation in semiconductor technology. This integration was possible purely because of the diverse subjects that I learnt during my PhD and master’s programs.
A critical turning point in my career was when I chose to pursue an industrial path rather than follow the academic route, despite completing an outstanding doctorate.
How did you plan the steps to get into the career you wanted? Tell us about your career path
As I mentioned previously, I was not entirely satisfied with my undergraduate field of study. Of course, within the bigger topic of Biotechnology I had several opportunities to delve into other subjects such as chemical engineering, material science, organic chemistry. I knew from the very first year that a “Biology” focused career was not for me. So, I started to focus on chemistry and materials related opportunities.
My first experience in materials development came during my summer internship at IIT-Bombay through the Indian Academy of Sciences, where I worked on development of nanoparticles for sensing applications. I enjoyed the hands-on experience in the chemical lab. For my final year thesis, I was able to obtain an international research intern scholarship to work at the University of Queensland, Australia, in a state-of-the-art research facility. This was the time that I was certain that I wanted to build a career in chemical research.
I was enthusiastic about the aspect of developing novel materials for energy related applications, but I also understood that my theoretical understanding was still limited at that time. To deepen my knowledge, I decided to pursue a master’s degree in Nanoscience at KU Leuven, one of the world’s leading universities in the world that offers this course. During this course, I was able to expand my knowledge in several chemistry and materials related topics (especially at the nanoscale). For my master’s thesis, I worked for a year at IMEC on the application of graphene as a pellicle layer for EUV lithography. EUV lithography is the most advanced lithography platform that is used in the fabrication of integrated chips used in smartphones and computers. I was glad that I was able to experience first-hand, tools at the forefront of semiconductor technology.
After my master’s, I did a PhD in the field of materials chemistry at the Ghent University in Belgium. My PhD was focused on development on nanoporous materials for energy applications. My PhD was funded by Geconcerteerde onderzoeksacties (GOAs which are ambitious, highly concerted projects conducted by multiple research groups as a collaborative effort. Each consortium member contributes expertise essential to the proposal’s implementation). This period was one of the most enriching experiences in my life. During my PhD, I was also able to work at TU Berlin, Germany for half a year as a researcher. I received the FWO travel grant for long stay abroad to work in Germany. My PhD work focused on photocatalysis which is a chemical process in which a substance (called photocatalyst) accelerates a chemical reaction when exposed to light. My role was to develop novel nanoporous photocatalysts which can improve the efficiency of the overall reaction while being robust and reusable. The advantages of using a photocatalytic process instead of traditional catalysis is that it minimizes the energy required for the reaction by using sunlight instead of heat. I also worked on electrocatalysis, which is similar to photocatalysis but instead of using light as the energy source, it uses electricity. Both approaches unlock chemical reactions using clean and renewable energy. They represent the future of chemical synthesis by enabling us to make fuels in a greener and sustainable way.
After my PhD, I moved to industry and currently work at JSR Micro NV, Belgium. JSR is one of the leading photoresist suppliers for the semiconductor industry with a worldwide presence. My work involves development of new photoresists and its application on cutting-edge lithography tools. In this job, I am able to apply my PhD expertise in polymer synthesis and characterization, along with the semiconductor technology foundation that I gained during my masters.
How did you get your first break?
I consider obtaining a research scholarship in Australia to be my first break. I was able to obtain this opportunity through an online application where I had to submit a motivation letter and outline my research interests. In retrospect, this process could have been easier if I had consulted guidance from others who had gone through similar applications. Nowadays, in the era of internet and computers, finding such mentors or contacts online is much easier.
Additionally, I would also like to address the transition from an academic environment to an industrial one. The first challenge is the language barrier in Belgium. At the university, proficiency in local language is not a requirement in Science and Engineering degrees. However, quite often industrial roles require at least basic skills in the local language. I had the opportunity to learn Dutch during my PhD. However, if learning the local language is not feasible, students should target international companies with a global working culture, where English is the main working language. This ensures that you will not be held back by language requirements.
Next step is to find companies where your skills align with their growth needs. Write CVs or motivation letters which are tuned towards the job profile. Please do not apply with generic CVs or motivation letters. In the first step, your application is most likely going to be screened using an AI bot. It is necessary that your CV format is AI readable and contains keywords relevant for the job to clear this screening process.
Preparation was the key to acing the job interviews. For me, my strong suit was technical questions and I answered them pretty well. For soft skills, a lot of information is available online for prepping interviews. It is best to prepare answers for such questions beforehand instead of trying to be spontaneous.
A practical challenge is that many employers hesitate to handle administrative processes if they are not familiar with hiring non-EU talent. Lookout for companies that already have non-EU working personnel.
Another common challenge as a master’s or PhD student is that a “student visa” is different than the “work permit” that allows you to work in the country. To tackle this issue, it is best to secure a job while still on a valid student visa and initiate the work visa process before graduation. This approach makes it easier to attend in-person interviews and ensures a smoother transition. If the student visa is about to expire, another option is to apply for a “job search” visa, which typically provides an additional year to look for a job while permitting you to remain in the country.
What were some of the challenges you faced? How did you address them?
One of my first challenges was deciding how to redirect my career away from biology and move towards something that I would truly like to study and explore. I addressed this by reviewing all the subjects that I had in my undergraduate curriculum and trying to map out what would be the most interesting for me. I narrowed down the choices to chemistry/materials, bioinformatics, and computational biology. Finally, I chose chemistry/materials as it was more hands-on.
Another challenge was the overall cultural and academic differences when I moved abroad for studies. The educational system and exams in India are much different compared to Belgium. It took some time for me to adapt to this, especially since all of a sudden I had to be independent in all aspects of life. However, this hurdle was also crossed through the support of family and friends.
Where do you work now? What problems do you solve?
I work at JSR Micro NV in Belgium. JSR is a chemical supplier for the semiconductor industry. I work as a senior product development engineer in the technology and application team. My main tasks are developing new photoresists for patterning different features in the range of 80nm up to >3µm. In addition, I have to work on the application of existing legacy products for various customers. This involves tuning and optimizing process parameters based on customer requirements.
What skills are needed for your role? How did you acquire the skills?
My role involves hands-on chemical lab skills to formulate photoresists using various polymers, additives etc. I developed these skills during my PhD research. In addition, a major part of my work requires me to be trained in a cleanroom environment and use the hi-tech tools there. This was acquired during my master’s thesis at imec and further evolved within my current role.
What’s a typical day like?
A typical day for me would be to understand customer targets and translate them into experiments. Based on this, I then process photoresists on Silicon wafers in a lithography tool inside a cleanroom. After processing, the output wafers are then tested on various tools to verify whether the experiments were successful or not. This requires quite a lot of data analysis, based on which I need to generate reports and provide chemical perspectives on why the results occurred as they did. After this, I discuss the results with the customer to decide next steps.
What is it you love about this job?
The main reason I love this job is I get to see the direct impact of my work in a relatively short span of time. When my work is successful, the materials I develop are used for manufacturing integrated chips that power a lot of devices that people use every day.
How does your work benefit society?
I develop new photoresists which are essential for the integrated chip manufacturers to create the modern day smart devices, from cell phones and computers to automotive power devices, MEMS, ASICs etc. Without the physical photoresists, there would be no digital world and you would probably be reading this on a printed paper instead of a computer screen. A photoresist is a light-sensitive material used in the lithography step of chip manufacturing. It is used to transfer a pattern from a mask onto a silicon wafer.
Imagine you want to paint the letter “A” on a wall. To do this, you take a stencil with an “A”-shaped opening and then you spray paint over it. The paint passing through the stencil opening is painted on the wall. Hence, when the stencil is removed you have the paint in the shape of “A” on the wall. Analogous to this, in chip fabrication, a photoresist coated silicon wafer is like the wall, the mask is the stencil, and the light is like the spray paint. When the light (spray paint) shines through the mask (stencil), it modifies the exposed regions on the photoresist (wall). In a next step, a chemical called developer is used to wash away the light-exposed region and thus leaves behind the exact pattern from the mask on the silicon wafer .
Tell us an example of a specific memorable work you did that is very close to you!
During my PhD, I worked on development of a new material belonging to the class of covalent organic frameworks that was used for the production of hydrogen peroxide. Hydrogen peroxide is an essential chemical used worldwide (e.g., as a disinfectant). Traditionally production of this is energy-intensive. With my material, I showed a way to make hydrogen peroxide using light which makes the overall process green. What makes this work memorable for me is that I was the first one to demonstrate this with covalent organic frameworks. Since then, a lot of researchers around the globe started working on this field and improving upon my work.
Your advice to students based on your experience?
My advice to students would be to choose your field with passion and purpose. Study what excites you, but make sure it matters to the world around you and can support your future. A hobby can bring happiness, but a career needs to sustain you. Please find the sweet spot where passion and purpose meet each other.
If you want to work in the industry, start building that path early on. Seek out internships, training programs, hands-on training etc. Don’t be shy about contacting people who inspire you. Reach out to your seniors or professionals online. Most of them might not reply, but the few who do could change the course of your career.
Future Plans?
The semiconductor industry in India is blooming after years of struggle. It would be great if I could contribute towards this growth.