Projection lithographic objective lens with sub-ten micrometerline-width and its MTF experimental measurements

We introduced the design method of a 2 reduction projection lithographic objective with double-telecentric structure by Zemax optical design software, which uses the 405nm laser diode (LD) as the light source and has 6 lenses. Its number aperture is NA=0.06, the resolution approaches to 5 m. In the field of view of 12 mm12 mm, its wave-front aberration is less than a quarter of wavelength and the distortion ratio is no more than 0.005%. We also measured the accurate optical transfer function (MTF) value by experiments after the projection objective was fabricated. Through analyzing the noise disturbance law in MTF tests we got the conclusion that the projection objective has sub-ten micrometer resolution.