A optical projection system

Abstract

The invention relates an optical projection system, which is used for imaging an image in an object plane to an image plane. A first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eight lens are successively arranged along an optical axis from an object side to an image side and a diaphragm is arranged between the fourth lens and the fifth lens. Besides, a back focus of a combined lens set including the first lens, the second lens, the third lens, and the fourth lens is in the center of the diaphragm; a front focus of a combined lens set including the fifth lens, the sixth lens, the seventh lens, and the eight lens is in the center of the diaphragm; therefore, a doubly telecentric structure is formed based on the above-mentioned arrangement. According to the optical projection system provided in the invention, if a technology factor is selected, wherein the technology factor is expressed as K1 being equal to 1.0 and is easily realized, a lithography resolution can completely reach 15 microns, so that a technical requirement of LDI lithography equipment of a PCB can be satisfied sufficiently; moreover, an optical material with high transmissivity is selected, so that an exposure requirement with large doses can be met.

Description

technical field [0001] The invention relates to a projection optical system for laser direct imaging (LDI) lithography of a printed circuit board (PCB), and can also be used for a projection optical system for photolithography and semiconductor packaging lithography. Background technique [0002] At present, in the field of printed circuit board (PCB) lithography equipment manufacturing, Israel Orbotech, which adopts laser direct imaging (LDI) lithography technology, occupies the largest market share. At the Japanese exhibition in May 2007, it announced that it had installed about 250 units. equipment, which in January 2008 claimed to have about 350 installed. The minimum line width of Orbotech's lithography equipment has been increased from 50um to 25um, and even to 15um. Other LDI lithography equipment is mainly provided by Japanese companies, such as Pentax, Fuji, and Dainippon Screen. The minimum line width of these lithography equipment has also reached the order of 15...

AI Technical Summary

Problems solved by technology

The patent provides the design data of the objective lens and the imaging quality, but the imaging quality cannot meet the technical requirements of the projection optical system of the printed circuit board (PCB) lithography equipment, and there are two glued surfaces, which do not meet the requirements of lithography. technical requirements

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