In this study, usually, arrays of square or rectangular piezo devices bonded to a substrate and spaced as close together as possible for transduction for efficient megasonic cleaning, megasonic cleaning is applied to removing sidewall particles during post-silicon etch cleaning. A system was developed containing different measures of ultrasonic and megasonic processes, generated by adjusting the power in NH₄OH. Megasonic waves in the gap between the wafer and the megasonic transducer ensure uniform sonic energy across the whole wafer. The generation of radicals is promoted by megasonic energy, such that residue removal occurs in dilute solution. The feature damage for the megasonic cleaning decreased in the NH₄OH solution compared to ultrasonic. Moreover, the mechanical force of the bubble cavitation generated by megasonic cleaning also improves residue removal and enhances the mass transfer rate. Extreme cavitation is beneficial for removing particles but can damage wafer features. The damage caused by ultrasonic cleaning is significantly larger than megasonic cleaning. Compared with typical methods of silicon oxide residues removal, this megasonic process has a low material loss and a high residue removal efficiency for via, with a high aspect ratio. In addition, it minimizes defects to structures. These results suggest that megasonic cleaning can be applied to the nanoparticle cleaning process. Megasonic cleaning is quickly becoming an efficient method for post process cleaning in IC fabrication processes.

In this study, a 10–50 nm Co₃₂Fe₃₀W₃₈ alloy thin film sputtered on glass substrates was annealed at different temperatures for 1 h including room temperature (RT), 300, 350, and 400 °C. The structure, magnetic properties, surface energy, and optical properties of the Co₃₂Fe₃₀W₃₈ alloy were studied. X-ray diffraction (XRD) patterns of the as-deposited Co₃₂Fe₃₀W₃₈ thin films showed the amorphous structure. The apparent body-centered cubic (BCC) CoFe (110) structure was exhibited after 300 °C annealing for 1 h. The 300 °C annealed Co₃₂Fe₃₀W₃₈ thin film showed the highest CoFe (110) peak compared with other temperatures. Furthermore, the thicker the Co₃₂Fe₃₀W₃₈ thin film, the higher the CoFe (110) peak. The CoFe (110) peak revealed magneto-crystalline anisotropy, which was related to the strong low-frequency alternative-current magnetic susceptibility (χ_ac) and induced an increasing trend of saturation magnetization (M_s) as the thickness (t_f) increased. Due to the thermal disturbance, the χ_ac and M_s for the 350 and 400 °C annealed Co₃₂Fe₃₀W₃₈ thin film decreased. The contact angles of the Co₃₂Fe₃₀W₃₈ thin films were less than 90°. For all temperatures, the surface energy increased when the film thickness increased from 10 to 50 nm. In addition, the surface energies for annealed samples were comparatively higher than the as-deposited samples. The higher surface energy of 28 mJ/mm² was obtained for the 50 nm Co₃₂Fe₃₀W₃₈ thin film annealed at 300 °C. The transmittance percentage (%) of the as-deposited Co₃₂Fe₃₀W₃₈ film was higher than other annealed conditions. This result contributed to the fact that higher crystallization, due to perfect band structures, may inhibit the transmission of photon signals through the film, resulting in low transmittance and high absorption.