Detection of Ultrafine Particles in Liquids Using a Breakdown Acoustic Effect

Abstract

As water and liquid reagents used in semiconductor technology and biochemical engineering are highly purified, analytical and detecting methods for ultratrace and ultrafine particulate impurities are desired. For example, ultrafine particulate matter as small as 10-1 pm can break the insulation between wiring on a very large scale integrated circuit (VLSI), so detection, counting or determination methods are required for the water and liquid reagents used in VLSI production. However, the weight concentration of these particulate impurities is estimated to be below 10⁻² ppt (number density: 10¹ mL⁻¹), and this is too small for turbidimetric or even photoacoustic determination [1]. On the other hand, the detection limit size of particle counting in liquids using laser scattering is about 0.1–0.3 μm, because of the background due to medium Rayleigh scattering. We propose a new method for counting ultrafine particles in liquids using a breakdown acoustic effect.