Combined technology method suitable for efficient processing of calcium fluoride convex cone mirror

Abstract

The invention discloses a combined technology method suitable for efficient machining of a calcium fluoride convex cone mirror. The material characteristics of calcium fluoride crystals and the characteristics of a convex cone surface special-shaped structure are fully considered, a machining process is divided into three links of forming, surface figure accuracy increasing and roughness increasing, three combined technologies of a milling forming technology, a diamond turning technology and a magneto-rheological polishing technology are adopted for machining, and the technological difficulties of the cone angle, surface figure accuracy, roughness and the like of a calcium fluoride convex cone are broken through one by one. Machining efficiency is high, the cone angle accuracy is high, the surface figure accuracy and roughness are controllable and stable, the technological difficulty that the special-shaped curved surface of the calcium fluoride convex cone cannot be machined in domestic existing technologies is broken through, and technological guarantees are provided for our country to carry out development of photoetching machine projection exposure optical systems.

Description

technical field [0001] The invention relates to the technical field of nano-precision precision machining, in particular to a combined process method suitable for high-efficiency machining of calcium fluoride convex cone mirrors. Background technique [0002] With the vigorous development of the electronic information industry, the integrated circuit manufacturing industry, which is the basis of the electronic information industry, presents a development trend of large-scale, miniaturized feature size, and high-density integration. The devices contained on the electronic chip have developed from dozens to Now contains hundreds of millions. Very large-scale integrated circuits have become the cornerstone of the development of high-tech fields. As a key process in the integrated circuit manufacturing industry, the exposure wavelength of the optical exposure machine changes from the near ultraviolet of 436nm and 365nm to the deep ultraviolet of 246nm and 193nm. Foreign compan...

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Problems solved by technology

[0005] (2) The application of optical systems often reduces the relative aperture to increase the depth of field, but it will reduce the spatial resolution of the system and blur the image details

[0010] (1)CaF 2 The axicon lens is a soft crystal material, the material is heterogeneous, and it is difficult to control the roughness and finish;

[0011] (2)CaF 2 The line speed of the axicon busbar is inconsistent during the processing process, and the line speed in the central area is almost zero, which leads to problems such as poor straightness of the busbar and uncontrollable damage layer in the central area after the axicon is processed by traditional technology;

[0012] (3)CaF 2 The normal of the mirror surface of the axicon mirror is different, the curvature of the mirror surface is inconsistent, the center of the cone is the inflection point, and the processing trajectory is limited. At the same time, the processing process cannot guarantee the consistency of the removal efficiency and the effectiveness of the surface shape convergence;

[0013] (4) In order to reduce the scattering rate of the cone surface, CaF 2 The surface roughness of the axicon lens is required to be within 0.5nm, limited to CaF 2 The special-shaped structure of the axicon lens cannot be directly adopted by traditional methods, and there is no mature and reliable processing technology in China

Due to the late start of research in this field in my country and the fact that CaF 2 Axicon mirrors are limited to special purposes, and there is no CaF for reference in China 2 Axicon lens processing experience

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