I am providing answers to the questions you asked!
1. Physical Limits of EUV and the Importance of ALD:
While the introduction of ASML's EUV has achieved semiconductor miniaturization to some extent, it is hitting physicochemical limits such as light diffraction stages and photoresist (PR) collapse. Therefore, along with EUV, ALD and multi-patterning technologies are essential for depositing thin and uniform films.
To elaborate further on ALD, its importance is increasing because it is virtually the only technology capable of uniformly coating thin films into deep and narrow gaps at the atomic layer level.
2. The Proportion of PECVD:
Since PECVD allows for processing at relatively lower temperatures compared to LPCVD, it can rapidly stack thin films while protecting heat-sensitive wiring or devices.
However, because ALD is used as an irreplaceable option for uniformly depositing in narrow and deep gaps, PECVD and ALD are used complementarily.
Therefore, it is difficult to say that one specific process is used more than the other. PECVD has the advantage of fast deposition without damaging the wiring, while ALD has the advantage of uniform deposition within narrow and deep gaps.
3. HBM and the Importance of Front-end Processes (?) & Wafer Size:
As you know, HBM is a technology that vertically stacks DRAM and connects them by drilling fine holes called TSVs (back-end process). In the process of forming insulation layers and filling conductive materials inside these holes, front-end technologies like PECVD/ALD are deeply penetrating the back-end process area. In other words, as the boundary between front-end and back-end processes collapses, the importance of deposition is on the rise.
Additionally, the wafers used are 300mm (12-inch) wafers. There were attempts to increase wafer size in the past, but since almost all equipment is already standardized to 300mm, the efficiency did not justify the equipment replacement costs, so the industry returned to 300mm.
Therefore, rather than increasing the wafer size, the current trend continues because it is much more economically and technically advantageous to make components smaller or stack them higher within a fixed area.
4. Future Plans:
I was planning to prepare a more practical, hands-on lecture, but I am hesitating because I'm not sure if that content would be helpful for job seekers. I would be very grateful if you could provide feedback on what kind of lectures are needed!
5. Important Competencies in Semiconductor Equipment Companies:
Since I am in deposition process research rather than a design role, it is difficult for me to speak specifically about design.
Nevertheless, regarding design roles, it seems important to go beyond simply being proficient with CAD tools; having a fundamental understanding of thermodynamics and fluid mechanics is advantageous. The ability to predict and suggest solutions for gas or heat flow inside the equipment and the resulting mechanical deformations appears crucial.
Regarding the process side, the core competency is data analysis skills to understand chemical reactions of gases or plasma characteristics and find the optimal process recipe.
Seeing that you asked these questions despite being a non-major, I can feel how hard you have been preparing! I'm not sure if my answers will be helpful, but if you continue to prepare step-by-step like this, you will definitely get accepted into the company you want!!