Fabrication and performance test of a compact-type magasonic waveguide for nano-particle cleaning

In this work, a compact-type megasonic cleaning system for semiconductor manufacturing was developed and its performance was verified. To design this megasonic system, firstly, an impedance analysis for a quartz megasonic waveguide with the piezoelectric actuator was performed with finite element method (FEM) software ANSYS. The obtained peak value of the anti-resonance frequency was 983 kHz, which showed good agreement with the design value of 982 kHz. In addition, acoustic pressures of the developed system was assessed by measuring acoustic pressures and comparing standard deviation values of them with a conventional megasonic system to evaluate the system performance. The analysis results showed that the standard deviation of the developed system was decreased by 38% compared to the commercial system. For another evaluation, the particle removal efficiency (PRE) test was performed with 80 nm particles. The experimental result revealed that the system has PRE of 91%. Based on the results, the developed megasonic system is regarded as an improved cleaning system which can irradiate more uniform acoustic pressures. As a consequence, it is thought to have higher energy efficiency and save the consumption of chemical and ultra pure water (UPW) in nano-particle cleaning.