300 mm is the wafer size. The wafers then get cut into chips. The whole production line has to be made so that it can process the wafer size. For a long time 2

300 mm is the wafer size. The wafers then get cut into chips. The whole production line has to be made so that it can process the wafer size. For a long time 200 mm wafers was the industry standard. That this is a 300 mm wafer fab implies that it is a high volume, fairly new fab that burned down.