Optimum spacing obtaining method for cooling pipelines on back side of mirror body in extreme ultraviolet collecting system

Abstract

The present invention discloses an optimum spacing obtaining method for cooling pipelines on the back side of a mirror body in an extreme ultraviolet collecting system. The optimum spacing obtaining method comprises the following steps of: S1, preliminarily determining an overall array layout scheme of the cooling pipelines on the back side of the mirror body according to distribution characteristics of a heat flux density of the mirror body; S2, building a physical heat transferring model which can reflect an actual situation; S3, building a numerical calculation model for heat conduction between the mirror body and the cooling pipelines, and preliminarily obtaining temperature distribution of the mirror body in the axial direction; S4, considering pipe-wall temperature difference caused by the situation that a water current absorbs heat and the temperature is risen, adding a group of energy conservation relational expressions in the calculation, and solving a more accurate mirror body temperature once again; and S5, on the basis of the steps of S1, S2, S3 and S4 of the technical scheme, writing an optimization procedure of an optimum spacing between the cooling pipelines, and adding a spacing between single pipes, which is as a final cyclic variable, into procedure operation so as to obtain the optimal solution of the spacing of the adjacent single pipes are obtained. According to the optimum spacing obtaining method disclosed by the present invention, the optimal solution of the spacing between the cooling pipelines can be accurately calculated, so that the uniform and stable temperature distribution of the whole mirror body in the extreme ultraviolet collecting system is realized, therefore, the array layout of the cooling pipelines is accurately designed in an optimizing manner.

Description

technical field [0001] The invention relates to a method for calculating the optimum spacing for the arrangement and layout of the cooling pipes of the reflection mirror body of the extreme ultraviolet collection system in extreme ultraviolet lithography. Background technique [0002] Near-extreme ultraviolet lithography (EUVL) is considered to be one of the most promising lithography technologies in the next generation. In recent years, several foreign extreme ultraviolet lithography research and development institutions have made some breakthroughs, such as the gradual and steady increase in the power of the light source, the continuous optimization of the design of the collection system, lighting system, and projection system, and the mask The preparation process of the plate and photoresist is continuously improved. [0003] However, in the initial stage of the development of extreme ultraviolet lithography technology, the research and development work only focused on t...

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Problems solved by technology

[0003] However, in the initial stage of the development of extreme ultraviolet lithography technology, the research and development work only focused on the improvement of the power of the light source, but did not pay attention to the problem of high heat introduction caused by the high-power light source under the working state of the system, and the high temperature caused by strong radiation has great impact on subsequent System life and performance impact is fatal

[0004] For the extreme ultraviolet collection system, if the absorbed high heat cannot be released in a timely and effective manner, the temperature of the mirror substrate will rise sharply within tens of seconds. On the one hand, it will cause thermal deformation of the mirror body of the collection system, resulting in The light rays cannot be effectively converged at the intermediate focal point, so that the collection efficiency of the collection system is greatly reduced, the light spot at the intermediate focal point will also be seriously deformed, and the energy distribution will be uneven, which is extremely unfavorable to the subsequent lighting system and exposure system. As a result, the quality of the lithography chip is poor, the output is low, and it cannot meet the requirements; on the other hand, the mirror absorbs high heat and causes a sharp rise in temperature, which seriously reduces the life of the mirror substrate and the film layer.

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