Supposed you irradiated two wafers through photomask. One of these wafers was covered with a negative tone photoresist and the other was covered with a positive tone photoresist. Despite performing the exposure in a clean room, some dust gets between the mask and the wafer, and the pattern of photoresist on the wafer contains defects. Suppose you want to start over with the same wafers. Which wafer is easier to return to its unpatterned state? That is, which wafer can the photoresist be more easily removed? The negative resist or the positive resist? Why