Photo-etching machine coherence factor measuring method based on CCD imaging

Abstract

The invention discloses a CCD image sensor based method for measuring the coherence factor of a photo-etching machine illuminating system online. The main body of a measuring system is mainly composedof three parts: (A) a CCD probe module composed of a pinhole, a lens set, and CCD; (B) a scanning control module composed of XY scanning console and a driver; and (C) a data acquisition and storage processing module composed of a data acquisition card and a computer. The method has the advantages that CCD is used to replace photoresist, through pin-hole imaging, the energy distribution of light spots collected by CCD is analyzed and calculated to obtain part of measurement values of coherence factors, the reutilization rate is high; the measurement precision is high, the responding time is quick, the light sensing time is shortened, the detection efficiency is improved; the CCD is connected to the computer, real-time automatic information processing and data storage are realized, the method is suitable for online detection of a photo-etching system installation and debugging process; the illuminating system coherence factor is measured on the mask surface, problems can be found in time, and the error can be accurately positioned.

Description

technical field [0001] The invention belongs to the field of collaborative optimization design of photolithography machine parameters, and in particular relates to an online measurement method for the coherence factor of the lighting system of the photolithography machine. Background technique [0002] The exposure system is a key part of the lithography machine, which is mainly composed of an illumination system and a projection system. [0003] The change of the coherence factor of the illumination system will lead to the change of the etched line width on the entire silicon wafer, and also cause the change of the focal depth and imaging contrast of the projection lithography system. The coherence factor is defined as the ratio of the diameter of the light source image on the entrance pupil surface of the objective lens to the aperture diameter of the objective lens, or as the ratio of the numerical aperture of the illumination system to the numerical aperture of the proje...

AI Technical Summary

Problems solved by technology

[0004] The traditional coherence factor measurement is measured on the silicon wafer surface after the whole system is integrated. The influence of the optical aberration of the projection system and the photoresist processing technology on the measurement results cannot be ruled out, and it cannot meet the requirements of real-time measurement during the development of the lighting system.

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