providing a wafer, wherein a pattern is disposed on the wafer;

placing the wafer on a photoresist spin coater, and a photoresist is injected on a central region of the wafer from a nozzle;

performing a spin coating step, wherein the spin coating step including: turning on the photoresist spin coater to rotate the photoresist spin coater to a first rotation speed, raising the first rotation speed to a second rotation speed, and performing braking several times in the process of maintaining the second rotation speed, so that the second rotation speed drops to a third rotation speed, and then rises to the second rotation speed again, wherein the rotation speed does not decrease below the third rotation speed prior to returning to the second rotation speed, and wherein during the spin coating step, the total time staying at the third rotation speed is less than 1/10 of the total time staying at the second rotation speed, wherein a reverse centrifugal force is generated and the photoresist converges from an edge region of the wafer to the central region of the wafer during the braking from the second rotation speed to the third rotation speed.