Cellulose-based eco-friendly wafer-cleaning reagent

Abstract

As the semiconductor industry has advanced, precisely patterned wafers of the sub-nanometer scale have been produced; hence, the development of cleaning reagents to remove contaminants from such wafers has received increasing attention. However, conventional cleaning solutions have significant drawbacks, including high cost and toxicity to both humans and the environment. In this work, we developed an eco-friendly cleaning reagent containing cellulose nanocrystals (CNCs) and a biodegradable amphoteric surfactant, cocamidopropyl betaine (CAPB), at optimal concentrations. The proposed system was applicable to both bare and patterned wafers, achieving a contaminant removal efficiency of ca. 100% without wafer damage. After investigating the cleaning mechanism utilizing different analytical techniques, we determined that the synergistic effect of the CNC/CAPB and free CAPB that includes the physical bombardment, electrostatic repulsion, and the adsorption inhibition of contaminants, contribute to the effective cleaning process. We expect this eco-friendly and cost-effective cleaning reagent to be readily adopted in the production of semiconductor products, as it could reduce the overall cost of producing electronics.