Cleaning Performance of High-Frequency, High-Intensity 360 kHz Frequency Operating in Thickness Mode Transducers

Authors: R. Vetrimurugan, Terry Lim, M. J. Goodson, R. Nagarajan

Abstract:

This study investigates the cleaning performance of high intensity 360 kHz frequency on removal of nano-dimensional and sub-micron particles from various surfaces, uniformity of the cleaning tank and run to run variation of cleaning process. The uniformity of the cleaning tank was measured by two different methods i.e. 1. ppbTM meter and 2. Liquid Particle Counting (LPC) technique. The result indicates that the energy was distributed more uniformly throughout the entire cleaning vessel even at the corners and edges of the tank when megasonic sweeping technology is applied. The result also shows that rinsing the parts with 360 kHz frequency at final rinse gives lower particle counts, hence higher cleaning efficiency as compared to other frequencies. When megasonic sweeping technology is applied each piezoelectric transducers will operate at their optimum resonant frequency and generates stronger acoustic cavitational force and higher acoustic streaming velocity. These combined forces are helping to enhance the particle removal and at the same time improve the overall cleaning performance. The multiple extractions study was also carried out for various frequencies to measure the cleaning potential and asymptote value.

Keywords: Power distribution, megasonic sweeping, thickness mode transducers, cavitation intensity, particle removal, laser particle counting, nano, submicron.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1099702

References:

[1] Vetrimurugan et al., “Experimental Investigation of Ultrasonic and Megasonic Frequency on Cleaning of Various Disk Drive Components”, International Journal of Chemical Engineering and Applications, Vol.4, No.4, pp. 174-177, 2013.
[2] Goodson, J.M., and Nagarajan, R., “Megasonic Sweeping and Silicon Wafer Cleaning”, Solid State Phenomena, Vol. 145-156, pp. 27-30, 2009.
[3] Nagarajan et al., “Megasonic cleaning to remove nano-dimensional contaminants from wafer surfaces: An analytical study”, Solid State Phenomena, Vol.195, pp.209 – 212, 2013.
[4] McQueen, D.H., “Frequency dependence of ultrasonic cleaning”, Ultrasonics, Vol. 24, pp. 273-280, 1986.
[5] Vetrimurugan, R., and Beng Hooi, N.G., “Study of ultrasonic parameters on removal of contamination from slider surface by using various cleaning chemistry”, International Journal of Chemical and Environmental Engineering, Vol. 3, pp. 392-396, 2012.
[6] Roger, W.W., Nagarajan, R., and Newberg, C.E., “Contamination and ESD control in High-Technology Manufacturing”, IEEE press, John Wiley and Sons, New Jersey, ch. 5, pp. 195-230, 2006.
[7] Goodson, J. M., and Skillman, “Megasonic Processing Apparatus With Frequency Sweeping of Thickness Mode Transducers”, US Patent, Patent No. US 8,310,131 B2, pp. 1-13, 2012.
[8] R. Nagarajan, R. W. Welker, and R. L. Weaver, Evaluation of aqueous cleaning techniques for disk drive parts, Microcontamination Conference Proceedings, San Jose, CA, Oct. 1991; 16-18: 312-326.