As competition in artificial intelligence (AI) semiconductors intensifies, process engineers are rapidly feeling a rise in technical difficulty. In particular, for advanced memory such as high bandwidth memory (HBM) and 3D NAND flash, structures are getting deeper and more complex, increasing the importance of etch processes.
Meeting on the 11th at the Applied Materials Korea headquarters in Hwaseong, Gyeonggi, process engineer Lee Do-yeop said, "The profile tolerance standards that customers require lately have become far stricter than before, and as new materials are introduced, by-products and defect mechanisms we have not previously experienced keep appearing."
After working about four years as a hardware engineer, Lee switched roles to process engineer and recently earned a graduate degree in electrical engineering from Hanyang University, deepening expertise in plasma. Lee now oversees the etch equipment Sym3 platform applied to Samsung Electronics' memory semiconductor processes and develops and optimizes flash memory etch processes.
Lee noted that the more advanced the process, the more important it becomes to optimize the entire flow together rather than focus on individual tool performance. Applied Materials provides integrated materials solutions (IMS) that link pre- and post-steps based on a tool portfolio that spans not only etch but also deposition, ion implantation, chemical mechanical polishing (CMP), cleaning, and metrology and inspection across semiconductor manufacturing.
Applied Materials, headquartered in Silicon Valley, is the world's largest semiconductor equipment company, and in Korea about 2,000 employees carry out research and development (R&D) and technical support for Samsung Electronics, SK hynix, and others. The following is a Q&A with process engineer Lee Do-yeop.
- Why did you move from hardware engineer to process engineer?
Working as a hardware engineer, I built experience solving equipment structure, operating principles, and facility issues. After that, I wanted a deeper understanding of what physical and chemical reactions occur inside the actual chamber beyond the equipment itself. I judged that if I could also acquire process understanding and optimization capabilities, I could create greater value as an engineer.
- What is the strength of having experienced both roles?
When problems arise, I can look at both the equipment and the process. I can quickly determine whether it is an equipment issue or a problem with the process recipe or plasma conditions, which speeds up root-cause analysis and problem-solving.
- Why did you go to graduate school?
Balancing work and study was not easy, but I wanted to grow further as a process engineer. Plasma is a complex field whose characteristics change greatly with small variations in conditions such as temperature, pressure, and gas composition. By studying plasma in depth in graduate school, I was able to interpret process phenomena more logically, which helped improve the reliability and accuracy of process development.
- What are your current responsibilities?
I am in charge of the Sym3 platform, an etch tool applied to Samsung Electronics' memory semiconductor processes. I develop and optimize certain etch steps within flash memory processes.
- What differentiates the Sym3 platform?
Recently, as semiconductors undergo miniaturization and an expansion of 3D structures, they are taking on increasingly deeper and more complex structures. The Sym3 platform applies pulse voltage technology (PVT) to control plasma precisely at the microsecond level. It can independently control the angle and energy of ions in the plasma, enabling stable vertical profiles even in high-aspect-ratio structures.
- What are Applied Materials' unique strengths?
We have a process portfolio that covers the entire semiconductor manufacturing flow, including not only etch but also deposition, CMP, cleaning, and metrology. In advanced processes, there are more and more challenges that are difficult to solve with a single step. Through IMS (Integrated Materials Solution), which jointly optimizes multiple steps such as etch, deposition, cleaning, and metrology, we support customers in improving performance and Production yield.
- What was the most memorable project?
We once carried out a project to increase etch speed to boost a customer's productivity. When we tightened process conditions, by-products accumulated inside the chamber during long runs. Together with engineers from the U.S. headquarters, we analyzed the root cause and jointly optimized the process conditions and cleaning steps, improving both productivity and Production yield.
- How do you feel the AI era on the ground?
With the spread of AI semiconductors, both memory and logic semiconductors are accelerating miniaturization and the shift to 3D structures. In the past, we could partially use process conditions accumulated from the previous generation for the next, but now a new approach is needed every time the generation changes. Customer requirements have become more stringent, and as new materials are applied, by-products and defects we have not previously experienced keep appearing. Rather than relying only on experience, it is important to quickly understand and solve new problems.
- What advice would you give to job seekers who want to become semiconductor engineers?
The most important capabilities are logical thinking and problem-solving. When a phenomenon occurs, you must be able to analyze the causal relationship between cause and effect. You need a perspective that understands the entire process flow rather than looking at a single step. Communication skills are also important because you have to collaborate with engineers from various departments.