Challenges and Trends of Dry Clean Process in Semiconductor Technologies

Following the advancement of semiconductors, the need for changes in the development of CLN processes arose as well. Issues such as the penetration limitations of WET chemical in miniaturization, the introduction of new materials for performance improvement, and the requirement for 3D patterning are becoming increasingly prominent. To overcome the limitations of existing WET processes, DRY CLN technology is being introduced by various equipment manufacturers. Initially, the market for DRY CLN focused on similar chemical-based process and had relatively simple equipment structures. However, as the range of applications and the diversity of chemistries increase, DRY CLN equipment requires optimization tailored to its purpose. When it comes to plasma sources, the choice between CCP, ICP and even high-frequency-based plasma sources is necessary depending on the situation, and such sources are currently under development. Not only generating radicals but also maintaining them is critical, which highlights the importance of chamber material selection, diverse coating methods, and the development of sub-processes to maintain the chamber condition, as equally important as the main processes. In terms of process methods as well, with the increasing demand for processes that require removal of fine etch amounts, the demand for ALE-type processes based on selectivity is growing. I want to share the direction of development for CLN equipment and processes in line with these changes.