Start with a DQ molecule (the molecule is a manufacturer variation), The DQ molecule will not dissolve in a base developer solution. UV light breaks the nitrogen molecule off, forming an unstable molecule. To stabilize itself, one of the carbon atoms in the ring pops out of the ring.
Once the solution is exposed to water, an OH group attaches to the carbon atoms, forming and acid. The Acid can then react and dissolve with the basic developer solution. In this way, the manufacturer can “print” circuit patterns on the wafer.