Optical projection system, exposure device and method

Abstract

The present invention provides a projection optical system which has a large image-side numerical aperture and a projection field of view, and has excellent mechanical stability in the face of vibration. Comprising the first imaging optical system (G1) for forming the first intermediate image of the first surface (R), the second imaging optical system for forming the second intermediate image based on the light beam emitted from the first intermediate image with a concave mirror (CM) (G2), a third imaging optical system (G3) for forming a final image on the second surface (W) based on the light beam emitted from the second intermediate image. Furthermore, the effective diameter (Ec) of the concave reflector, the distance (L) between the first surface and the second surface, and the distance (H) between the concave reflector and the reference optical axis (AX) satisfy predetermined conditional expressions.

Description

technical field [0001] The present invention relates to a projection optical system, an exposure device and an exposure method, in particular to a high-resolution catadioptric projection optical system, which is suitable for manufacturing semiconductor elements and liquid crystal display elements by photolithography Projection exposure equipment used in other times. Background technique [0002] In the photolithography process used to manufacture semiconductor elements, etc., a method is used to expose the image of the pattern on the photomask or grating (hereinafter collectively referred to as "grating") to a surface coated with photoresist, etc., through a projection optical system. A projection exposure device on a wafer (or glass sheet). On the other hand, as the degree of integration of semiconductor elements and the like increases, the resolving power (resolution) of the projection optical system of the projection exposure apparatus is required to be also increased. ...

AI Technical Summary

Problems solved by technology

[0006] However, in the conventional projection optical system described in International Publication No. WO01 / 65285, the effective diameter of the concave mirror located in the catadioptric second imaging optical system constituting the protrusion is relatively large, so when vibrating, Mechanical stability is easily damaged

In addition, since the effective diameter of the lens arranged adjacent to the concave mirror becomes relatively large, when the lens is formed from fluorite, it is not easy to obtain and process a material having predetermined characteristics.

[0007] Moreover, in the conventional projection optical system, the distance between the object plane and the image plane (geometric distance) is relatively large, so the mechanical stability against vibration is easily damaged

However, when installed in an exposure device, the distance between the grating and the wafer becomes relatively large, so the operability is easily damaged, and it is easy to be limited by the height of the clean room

Also, when installed in an exposure device that utilizes exposure light below 200nm, for example, the relatively long projection light path will become filled with inert gas, which is unfavorable for the removal of inert gas

[0008] In addition, in the conventional projection optical system, the distance from the concave mirror in the catadioptric second imaging optical system constituting the protrusion to the reference optical axis (the optical axis of the first imaging optical system and the third imaging optical system) bigger

As a result, the mechanical stability is easily damaged in the face of vibration, and manufacturing errors are likely to occur at the time of assembling the second imaging optical system.

And when assembled in an exposure device that utilizes exposure light below 200nm, for example, the relatively long projection light path will become filled with inert gas, which is unfavorable for the removal of inert gas

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