Mitigating arcing defect at pad etch

This paper presents a method to mitigate arcing defect encountered at pad etch. The problem was detected during wafer disposition due to equipment alarm. Based on observation, this burnt- like defect material, is observed to have inhibited the wafer surface and exposing the top metal line. The inclination was observed mainly during main etch step. The wafer is believed to have encountered plasma instability during transition from Main Etch (ME) to Over Etch (OE) step. However, this is only detected during backside helium leak alarm. This arcing defect was caused by several factors, of which were related to recipe, wafer condition, processing tool and product design. The approach taken was to mitigate these issues where recipe optimization and tighter equipment parameter control were implemented. The design of experiment was presented to find the optimal setting for backside helium flow and chucking voltage. Apart from that, chamber mix run also plays an important role.