A method of making a device includes forming a first photoresist layer over an underlying layer, patterning the first photoresist layer to form a first photoresist pattern, rendering the first photoresist pattern insoluble to a solvent, forming a second photoresist layer over the first photoresist pattern, patterning the second photoresist layer to form a second photoresist pattern over the underlying layer, and etching the underlying layer using both the first and the second photoresist patterns as a mask.