A new plasma source for photoresist ash and residue removal

Summary form only given. A new microwave driven (2.45 GHz) plasma source has been developed at Fusion Systems Division of the Eaten Corporation´s Semiconductor Equipment Operation, to be used as a downstream asher. It operates by exciting the TM/sub 012/ resonant microwave mode in a cylindrical cavity structure. The source consists of an internally tuned microwave cavity that dynamically adjusts the cavity dimensions to match all changes in the plasma impedance. This is accomplished by a sliding short, and adjustable antenna lengths. Internal tuning ensures maximum power input to the plasma for all operating conditions by minimizing reflected power to less than 1% over a large operating window. Due to its novel internal tuning mechanism, there is no need for any external matching network, and therefore negligible power is lost to this internal matching unit. The plasma is totally contained in a dielectric tube running through the length of the cylindrical microwave cavity and is transported downstream for ashing.