Patent attributes
A method for cleaning a semiconductor substrate without damaging its patterned structure via an ultra/mega sonic device comprises applying liquid into a space between the substrate and the sonic device; setting an ultra/mega sonic device power supply at a frequency f1 and power P1; and at zero output before bubble cavitation occurs; followed by at f1 and P1 again after bubble temperature is lowered; detecting power on time (at P1, f1), power off time or amplitude of each waveform output by the power supply; comparing the detected power on time with a preset time T1, power off time with a preset time τ2, amplitude of each waveform with a preset value, if the detected power on time is longer than τ1, or power off time is shorter than τ2, or amplitude of any waveform is larger than the preset value, shut down the power supply and send out an alarm.
