Electrophoresis-driven agglomeration enables filtration-based removal of sub-100 nm silica nanoparticles from semiconductor industry-grade processing chemicals

Trace sub-100 nm impurities in processing chemicals represent a major yield-limiting challenge for sub-10 nm semiconductor manufacturing because they are difficult to remove using conventional purification methods. Mechanical filtration is ineffective for capturing nanoparticles smaller than 100 nm, while dielectrophoresis (DEP) exhibits limited performance for low-permittivity nanoparticles such as silica because the dielectrophoretic force is proportional to the particle volume and the Clausius-Mossotti factor. Here, we report a scalable purification strategy that integrates electrophoresis (EP) with standard centrifugal filtration to overcome these limitations. Unlike DEP, EP directly couples to the intrinsic surface charge of nanoparticles, enabling effective manipulation regardless of the particle size, permittivity, or electrode geometry. Under a DC bias, localized pH gradients gen…