Abstract:

Organic contamination present in Ultrapure Water (UPW) and other process fluids pose a risk of depositing on wafers during processing and cleaning. Organic contaminants include monomers, dimers, oligomers, and polymers of various molecular weights and chemical compositions which influence adhesion and volatility. “Critical organics” which adhere to the wafer surface are more likely to result from non-volatile and semi-volatile organics.

To aid the industry in mitigating the risk from critical organic contaminants, the IRDS Critical Components team aims to establish critical organics extraction limits for PVDF and PFA components. The objectives of this work are to determine if organics extracted from "critical components” can deposit on a silicon wafer under spin processing conditions and what portion of the extract remains on the surface following various elevated drying conditions. A secondary objective is to identify and develop test methodologies that might be suitable to incorporate in future revisions of SEMI F57 and related specifications.

Before this work we did not know if the organics from polymer components would meet the definition of critical organics. The data from complementary analytical techniques indicates that non-volatile and semi-volatile portions of the PFA and PVDF extracts remain adhered to the wafer, so we know now that polymer components are potential sources of critical organics. Finally, we encourage the SPCC community to continue to address the fundamental knowledge gap on critical organics to help quantify and manage the risk to yield.