Sudhian Media has posted an article on Processor Fabrication

Once these masks have been created, they are put over the wafer in turn. The short wavelength light is passed through by the holes in the quartz mask, to the photo-resist material covering the wafer. Then both the light and the mask are removed. A chemical etch is used to remove the exposed photo-resist, and with it the silicon dioxide immediately below it. This gives access to the layer of silicon below.

Read more