Illumination system

Abstract

The invention relates to an illumination system, which sequentially comprises a light source, a filter, a shutter, a coupling group, a quartz rod, a relay group and a mask surface along the propagation direction of a light beam, wherein the coupling group adopts an aspheric lens, the filter, the aspheric lens, the quartz rod and the relay group are positioned on the same optical axis, the light beam emitted from the light source is subjected to filtering through the filter, and then is incident on the aspheric lens through the shutter, the light beam coupled through the aspheric lens is subjected to light balancing through the quartz rod and then is incident on the relay group, and the obtained light beam is amplified by the relay group and then is imaged on the mask surface. According to the present invention, the aspheric lens is used as the coupling group, such that the number of the coupling group lenses is reduced, the transmittance of the system is increased, the spherical aberration of the coupling system is reduced, and the coupling efficiency of the system is improved; and the filter is placed between the light source and the shutter, such that the temperatures of the shutter and the coupling group are substantially reduced, and the service lives of the shutter and coupling group are prolonged.

Description

technical field [0001] The invention relates to the field of photolithography equipment, in particular to an illumination system. Background technique [0002] Most of the existing semiconductor manufacturing adopts photolithography technology, which is used to print characteristic patterns on the surface of the substrate. The frequently used substrates are semiconductor wafers or glass substrates coated with light-sensitive media on the surface. During the lithography process, the wafer is placed on the wafer stage, and the characteristic pattern is projected onto the wafer surface through the exposure device in the lithography equipment. During this process, the illumination of the silicon wafer surface is an important parameter of the lithography machine, and its size will be It affects the exposure time of the photoresist, which in turn affects the productivity of the photolithography machine. At present, improving the illumination of the lighting system is an urgent pr...

AI Technical Summary

Problems solved by technology

Since the filter 52 is placed in the coupling group 50, the thermal load of the shutter 40 and the coupling group 50 is relatively large, and the higher heat is easy to burn the shutter 40, and the film layer of the coupling group 50 lenses deteriorates, thereby reducing the shutter 40. and the service life of the coupling group 50, not only brings unnecessary workload to the system replacement components, but also increases additional costs; the coupling group 50 adopts the structure of four spherical optical lenses 51, although it can meet certain illumination requirements, but There is a low coupling efficiency. When using a traditional lighting system, taking the uniform field of view of 54mm×34mm and the input power of the light source as an example, the energy entering the quartz rod 70 is 77.76W, and the energy of the uniform field of view spot is 60.546W. Lighttools simulation analysis, the simulation results are as follows figure 2 As shown, the results are as follows: pupil uniformity ellfield=0.26%, Ellcheck=0.14%; the simulation results of field uniformity are as follows image 3 As shown, its uniformity is 0.92%. In addition, the traditional lighting system still has problems such as large volume, high cost, and complicated structure.

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