Simulation of surface deformation for the lithographic object lens by Zernike polynomials

Surface deformation is the crucial factor for the imaging performance of the lithographic object lens in the manufacturing process. Simulation of surface deformation can predict the degradation of the wavefront error caused by surface deformation, find the lens which is most sensitive to the surface deformation even in the design phase. We develop a method to simulate the surface deformation by Zernike polynomials in this paper. In fact, the surface deformation generated in the manufacturing process is random. However, it does not mean that they have no rules at all. We analysize the Zernike coefficients distribution of the interferential data, and build a model to simulate the surface deformation. The model can generate random-surface-deformation according to the input RMS/PV bound in the form of INT file type, which can be added to the lens surface directly in the optical design program CODEV. The results show that the surface deformation generated by our model can simulate the interferential data very well.