Method of improving photoresist profile

摘要

A method of improving a photoresist profile. After a photoresist layer is developed, a hard bake is performed at a temperature lower than a glass transition temperature of the photoresist layer. The photoresist layer is thus able to reflow, so that the profile can be modified. Or alternatively, the hard bake step can be replace by first performing a hard bake at a temperature higher than the glass transition temperature, followed by performing a flow bake at a temperature lower than the glass transition temperature.