Megasonics compared to Ultrasonics:
In a typical Ultrasonic cleaning process, the transducer works with a frequency between 25 kHz and 100 kHz.This lower frequency creates bigger bubbles up to diameters of 150 µm and creating higher cavitation energy when they collapse. Megasonic processes utilize frequencies from 600 kHz up to 4 MHz. These higher frequencies create smaller bubbles and when they collapse, producing a proportionally smaller amount of cavitation energy.
The high cavitation energy produced in Ultrasonic cleaning can damage sensitive structures of substrates. The gentler cleaning energy produced by Megasonic waves is able to remove particles down to 34 nm without damaging sensitive devices.
The following chemicals are strictly forbidden to use:
Hydrofluoric Acid (HF)
Buffered Hydrofluoric Acid (BHF)
7-up (Sulfuric Acid (H2SO4) + Hydrogen Peroxide (H2O2))
Sodium Hydroxide (NaOH)
Any chemical with a flash point < 100°C
Any mixture with an exothermic reaction with T > 70°C
The following chemicals are allowed with precautions:
Ammonium Hydroxide (NH4OH)
Hydrogen Peroxide (H2O2)
Developers and Removers (e.g. NMP, Nanostrip) (flash point > 100°C)
The following chemicals are allowed without special precautions:
Non-solvent based Detergents (e.g. Valtron SP2215)