Comparison ultrasonic vs. megasonic
Comparison of the ultrasonic frequency of 40 kHz and 1 MHz during the developing process within the LIGA-Technique
An important advantage of the application of Megasonic is the smooth cleaning of extremely fragile microstructures. The figure on the left shows that the microstructure has been destroyed by the high cavitation energy at the ultrasonic frequency of 40 kHz. The destroyed ridges have a thickness of approx. 4 µm. At an ultrasonic frequency of 1 MHz, the microstructure remains undamaged (fig. on right).
Destroyed fragile microstructure approx. 200 µm high, developed at a frequency of 40 kHz.
Undamaged fragile microstructure 400 µm high, developed at a frequency of 1 MHz.
Process support for the development of microstructures with high aspect ratios
The residue-free development of dense and deep structures is of particular importance when it comes to producing microstructures via X-ray lithography.
During the development process of microstructures (e.g. LIGA technology) with high aspect ratio, the particles are completely flushed out due to the created microflow, and the development time is reduced by a factor of 7. For fragile structures, the depth of the structures can be increased by a factor of 2.
Microstructure developed without Megasonic support
Microstructure developed with Megasonic support