Lift Off Resist Operation
S-Cubed employ’s two methods of lift off processing depending on customer requirements. The first technique is to “soak” the wafers to be “lifted off” in hot (approximately 70C) NMP. The treated wafers are then placed on a “pin” type chuck and “blasted” 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 inerted for safety and the process is both fast and effective.
In this way the entire process is carried out without operator involvement, eliminating problems caused by improper sequencing. Further the entire tool does double duty thereby saving time, money and footprint…lowering the cost of ownership.