Nano Particle Control on 300mm-wafers in Supercritical Fluid Technology

Abstract

The nano particle control in the supercritical fluid technology using CO 2 (SCCO 2 ) is extremely essential for SCCO 2 to enter a 300 mmSi-wafer semiconductor industry as a viable technology. In this study, we explored the basic particle removal behavior of SCCO 2 , varying the process recipe of the SCCO 2 operation and the size of nano particles (PSL: polystyrene latex). The SCCO 2 with Methanol as a non-solvent for PSL has indicated that PRE (particle removal efficiency) has the dependency of the nano particle size (weight) and hit the highest level of around 45 % on the smallest PSL (75 nm-dia.) particles. The SCCO 2 with Pyridine as a solvent for PSL has shown that its PRE has a similar tendency as seen on Methanol, but indicates a higher level of around 55 % than that of the SCCO 2 with Methanol.

Contamination Control in Supercritical CO2 Drying Process for Nano-Scale Memory Manufacturing

“…Furthermore, in the case of "direct feed with gas phase CO 2 ", the particle counts were found to be significantly less. The results indicate that organic contaminants in the CO 2 raw material were transported by supercritical CO 2 fluid with a high density (5). Delivering the supercritical CO 2 fluid using the CO 2 purification system has shown superior performance for removing nanosize particles.…”

“…CO 2 has zero surface tension, is nonflammable and nontoxic, and has an easily accessible critical temperature. However, supercritical CO 2 drying has not been implemented in 300mm wafer manufacturing yet because of a number of serious issues that have been encountered (5,6,7,8). These include the background levels of particles and metallic contaminants.…”