A system and method for photoresists is provided. In an embodiment a cross-linking or coupling reagent is included within a photoresist composition. The cross-linking or coupling reagent will react with the polymer resin within the photoresist composition to cross-link or couple the polymers together, resulting in a polymer with a larger molecular weight. This larger molecular weight will cause the dissolution rate of the photoresist to decrease, leading to a better depth of focus for the line.