Prism design method, self-reference interferometer, design method of self-reference interferometer and alignment system

Abstract

The embodiment of the invention provides a prism design method, a self-reference interferometer, a design method of the self-reference interferometer and an alignment system prism named as a first light field rotating prism. The design method comprises the following steps: establishing a Cartesian coordinate system XYZ, and setting a cuboid PEAL1-H1K1B1G1 and a cuboid H1K1B1G1-F1D1J1I1 in the Cartesian coordinate system; determining three inner reverse sides of the first light field rotating prism, namely a first inner reverse side, a second inner reverse side and a third inner reverse side; adjusting the rotation angle alpha 1 of the first light field to control the rotation angle of the incident light in the first light field rotation prism; locating the vertical projection of a connecting line between the vertex where the first inner reverse side and locating the midpoint where the second inner reverse side in the plane H1K1B1G1 is a line segment T1. The vertical projection of a connecting line between the vertex where the third inner reverse side is located and the midpoint where the second inner reverse side is located in the plane H1K1B1G1 is a line segment T2, and the firstlight field rotation angle alpha 1 is an included angle formed between the line segment T1 and the line segment T2. According to the embodiment of the invention, rotation of the light field at any angle is realized.

Description

technical field [0001] Embodiments of the present invention relate to optical equipment technology, and in particular to a design method of a prism, a self-referencing interferometer, a design method thereof, and an alignment system. Background technique [0002] Lithographic projection apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A critical step in the lithography process is to align the substrate with the lithographic apparatus so that the projected image of the mask pattern is in the correct position on the substrate. Semiconductors and other devices due to lithography require multiple exposures to form multiple layers in the device, and it is important that these layers are properly aligned. As smaller features are imaged, the requirements for overlap and thus the accuracy of alignment operations become more stringent. In an exemplary alignment system, the marks on the substrate include two pairs of reference gratings, one X and ...

AI Technical Summary

Problems solved by technology

However, in the existing technology, the self-referencing interferometer can only realize the rotation of the light field by 180°, which cannot meet the demand for the rotation of the light field at any angle.

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