A method of forming a patterned photoresist layer. First, an anti-reflection coating layer is formed on a substrate. Next, a first bake is performed. A photoresist layer is then formed on the anti-reflection coating layer. Exposure is performed. A second bake is performed, wherein the temperature difference between the first bake and the second bake is about 35 ° C.˜55 ° C. Finally, development is performed. The patterned photoresist layer features have perfect profiles in accordance with this invention.