Hello I am looking for a method to clean the holes' walls of polyimide and Mylar films. The holes was drilled by excimer laser. The diameters of holes are in 20um~125um. PI or Mylar film's thickness is 100um. There are debris , carbine and carbon black sticking on the surface and wall of holes. I have tried to clean them with acetone . But obviously I cannot reach the wall of the holes. Can ultrasonic cleaning work it out? How much should be power and frequency of the ultrasonic cleaner ? Is there any kind of solvent can help to clean them? Thanks in advance Oliver Tseng Project Manager K-Jet Laser Tek. Inc. www.kjet.com.tw Taiwan