Wafer size transition from 300mm to 450mm has been started to address the higher manufacturing cost issue. Major challenges for front end of line (FEOL) clean are listed. From preliminary results, cleanness and etching uniformity are very positive with comparable or even better particle adder performance. Pattern collapse and damage become more and more critical to advanced technology node, but currently they couldn’t be tested due to the lack of 450mm pattern wafer. For 450mm wafer recycling, it will be done in single wafer processing tool instead of batch tool, good results in terms of short process time and low surface roughness were obtained on SiO2 and Si3N4 recycling wafers. Same as 300mm, single wafer processing tool for Si3N4 wet etching is requested.