Metal Lift Off Cleaning
S-Cubed employs two methods of lift off processing depending on
the needs and practices of the customer. The first technique is to “soak” the wafers to be “lifted off” in hot ( approximately 70C) NMP followed by placing the treated wafers on a pin chuck and “blasting” with high pressure NMP followed by an IPA rinse followed by DIW spin rinse and dry. All of the spin process are carried out on the chuck with the various fluids discharged into annular drains at differing heights so that fluids can be recycled or discharged as appropriate.
The second method is somewhat simpler and can be done effectively at lower cost in a simpler system. We simply blast the wafer surface with high pressure acetone and use a recycling system to recover the spent acetone with the final acetone rinse being the means by which the recycling material is refreshed. The system is Nitrogen innerted for safety and the process is both fast and effective. The images below are the micro graphs of metal films after such lift off processing.