Method for optimizing photoresist membrane thickness of ion implantation layer

The invention discloses a method for optimizing the photoresist membrane thickness of an ion implantation layer. The method comprises the following steps: providing a test wafer; forming a photoresist on the test wafer, wherein the photoresist membrane thickness is distributed on the test wafer in a continuous gradient mode; measuring the photoresist membrane thicknesses at different positions on the test wafer; dividing the test wafer coated with the photoresist into an exposure development area and an ion implantation test area, carrying out exposure development on the exposure development area and manufacturing a key dimension swing curve; implanting ions with predetermined energy into the ion implantation test area, and determining a photoresist membrane thick scope according with an ion implantation blocking requirement; and according to the photoresist membrane thick scope according with the ion implantation blocking requirement and extreme points in the key dimension swing curve, determining the optimum membrane thickness of the photoresist of the ion implantation layer. According to the invention, the application amount of the measuring wafer is reduced, the technical procedures are reduced, the manufacturing cost of the test wafer is decreased, and at the same time, a most proper photoresist thickness point is found.