Wet Processes of Megsonic Cleaning, CMP, Development, Etching for Semiconductors

Ultrasonic cleaning technology is one of the most commonly used industrial cleaning technologies. The traditional ultrasonic cleaning technology is to remove the stains on the surface of the object through the ultrasonic cavitation at 20khz-100khz in the liquid. However, too strong ultrasonic cavitation will result in certain damage to the surface of the object. For example, for cleaning of precision components such as semiconductor devices and optical precision parts, due to the microstructure on the surface of the devices, the traditional high-frequency ultrasonic cleaning process will cause damage to the surface. In addition, the higher the ultrasonic frequency, the smaller the particle size of the cleaned impurity particles. The traditional ultrasonic cleaning with up to 100kHz in frequency is difficult to remove the tiny particles below 1 micron.

Figure 1：Megasonic Nozzle

When the ultrasonic wave with frequency higher than 400kHz propagates in the liquid, it can form a very thin acoustic boundary layer with large velocity gradient near the surface of the cleaned part, and its impurity particles fall off from the surface of the device under the vibration of liquid in mega-hertz, which can remove the micron and submicron impurity particles away from the surface of the object, so as to realize the ultra-precision cleaning process. In addition, due to the extremely low cavitation effect, the megasonic cleaning process will not damage the surface of the object, which can effectively solve the corrosion or damage issue during the cleaning processes of precise devices. Therefore, megasonic systems that can emit mega-hertz are widely used in semiconductor manufacturing, and besides cleaning, they can also play an important role in other key processes such as CMP (chemical mechanical polishing), photoresist development and stripping, etching, lift-off, etc. 

Typical applications of Siansonic megasonic cleaning systems

Siansonic offers a variety of patented megasonic cleaning products from 400kHz to 3000khz (3MHz), including batch type (bath cleaning), shower type and cover type megasonic cleaning systems, for various wet processes on wafers, MEMS, etc.

Benefits of Siansonic megasonic cleaning systems

• Extremely low cavitation effect will not damage the device surface.

• Ultra-precise cleaning, ability to remove particles in 0.2 micron.

• Made from highly corrosion resistant materials, suitable for various acid, alkali and organic solvents.

• Quartz or sapphire cleaning surface gives no risk of impurities falling off from the system.

• Megasonic generator with the 3rd generation semiconductor technology provides digital driving in high frequency and high power.