Mask Light Develop

A wafer of photoresist sits under the lamp, and the faint ghost over the grid is the pattern that has to come out of the developer. Press and drag to walk the UV head across the wafer: whichever cells it sits over start taking on dose, and the dose stays where it lands. Cells that belong to the pattern have to be brought up into their window - too little and they will not open, too much and the resist burns through and the whole wafer is scrap. Cells outside the pattern have to be steered around rather than driven over. Open every cell that belongs to the pattern to finish the wafer; after that the patterns get more scattered, the window narrower, and the lamp spot smaller.