The wafer is transferred from the photolithography development bench to the wet etch bench.
In the wet etch bench, the wafer is held using a specially fashioned wand made of a chemically resistant plastic. The wand fits into a slot in the transparent cover of the baths. It is designed so that the wafer must pass through all four baths before being removed from the bench.
The first HF acid bath etches away the oxide layer where it has been exposed by the photoresist pattern.