Novel functionalized membrane approaches to metal contamination control in advanced lithography filtration

Abstract

As the semiconductor industry continues to advance and on-wafer defect reduction by liquid filtration has become “universal” as a process enabler for advanced technology nodes, the need for innovative filtration solutions that reduces target contaminants has become critical. Filtration technologies for metal cleanliness in photochemicals, including lithography materials and solvents, continue to grow and contribute to die yield improvement at wafer level. Both point-of-use (POU) and bulk filtration play important roles in achieving high-purity chemicals and processes by eliminating metal contaminants in critical fluids. However, the increasing complexity of photochemicals, such as multicomponent resist formulations (organic or inorganic), necessitates advanced filtration membrane technology that is compatible with their various components, including the metal oxide nanoparticles. In this regard, the ideal filtration technology should rely on functionalization with tailored chemistries to selectively remove target metals, without interactions with the key components in photoresist formulations. Also, due to the variation in forms and species of metals in different fluids, the next generation filtration technology should be able to act as a versatile platform with customization capability to optimize removal efficiency in each fluid. The objective of this study is to demonstrate the metal removal performance of different functionalization chemistries on PTFE and HDPE membrane and investigate the impact of various surface modification designs on removal selectivity and efficiency.