Position measurement system

Abstract

The invention discloses a position measurement system, which is used for automatic alignment of a measurement mark. The position measurement system is characterized by comprising an illuminating optical system, a projection optical system, a detection optical system, an image collecting and processing unit and a control unit, wherein the illuminating optical system is used for providing an illuminating beam projected to the measurement mark; the projection optical system is used for guiding the illuminating beam including measurement mark information to the surface of a to-be-measured object; the detection optical system is used for receiving reflected light which is reflected by the illuminating beam including the measurement mark information through the surface of the to-be-measured object and projecting the reflected light to a detection mark; the image collecting and processing unit is used for collecting an image which is formed by the measurement mark through the projection optical system and the detection optical system and obtaining deviation information of the measurement mark according to the image; the control unit is used for controlling a drive unit according to the deviation information; the drive unit is connected with an adjusting unit; and the adjusting unit drives the drive unit to adjust the image of the measurement mark according to the deviation information.

Description

technical field [0001] The invention relates to the field of integrated circuit equipment manufacturing, in particular to a position measurement system. Background technique [0002] In order to meet the increasingly narrow linewidth requirements of integrated circuits, it is necessary to continuously reduce the operating wavelength of the projection objective lens of the lithography machine and increase its numerical aperture to obtain higher resolution. However, as the working wavelength of the projection objective lens decreases and the numerical aperture increases, its depth of focus becomes smaller and smaller. This requires continuous improvement of the measurement accuracy of the vertical position of the silicon wafer surface so that it can be accurately positioned on the projection surface. The plane of best focus of the objective lens. At present, most of the sensors used to measure the vertical position of the silicon wafer surface adopt photoelectric measurement ...

AI Technical Summary

Problems solved by technology

[0004] However, in order to accurately align the projection mark and the detection mark, an off-line manual method is usually used at present, and only a few components can be automatically adjusted when the whole machine is integrated or the lithography machine is working. This adjustment method strongly depends on the optical mechanical assembly. The engineer's experience and luck, long adjustment time, low efficiency, and repeated repetitions greatly restrict the productization process of displacement sensors and even the entire lithography machine

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