Insulator-Based Dielectrophoresis for Purifying Semiconductor Industry-Compatible Chemicals with Trace Nanoparticles

As semiconductor scaling advances below 2-3 nm dimensions, precise control of nanoscale impurities becomes crucial for maintaining device performance and production yield. Conventional purification methods, such as distillation and filtration, are ineffective in removing nanoparticles smaller than 10 nm. This study investigates insulator-based dielectrophoresis (iDEP) for efficient removal of silica nanoparticles from semiconductor processing chemicals. Interdigitated electrode patterns fabricated on sapphire substrates were employed to generate high electric field gradients, facilitating nanoparticle aggregation. A 20 nm-thick aluminum oxide passivation layer was deposited via atomic layer deposition to prevent electrode degradation. Finite element method simulations confirmed that the strong electric field gradient necessary for nanoparticle aggregation was generated at the electrode edges. The optimal frequency for nanoparticle aggregation was determined using the Clausius-Mossotti factor, and large-scale iDEP experiments demonstrated a 41.3% reduction in Si concentration in deionized water and a 23.4% reduction in 2% nitric acid after 12 purification cycles. This method effectively removes the nanoparticles that are difficult to eliminate using conventional techniques, enhancing the purity of semiconductor processing chemicals. The study demonstrates iDEP's scalability, high throughput, and reliability for industrial applications, offering a promising solution for meeting purity standards in semiconductor fabrication.