Field measurement device of wave aberration of projection objective in photo-etching machine

Abstract

The invention relates to a field measurement device of wave aberration of a projection objective in a photo-etching machine. The device is based on the shack-hart mann measurement principle, and comprises a host machine and a standard lens, wherein the host machine comprises a photoelectric sensor, a diffraction optical element, a collimator objective, a pinhole maskplate provided with a round hole, and a beam splitting device used for controlling light path transmission; the standard lens includes a first standard lens used for folding back light path when in systematic error of the demarcated host machine, and a second standard lens used for folding back the light path when the wave aberration of the projection objective is measured by the host machine. The host machine and the first standard lens are integrated on a reticle mask stage of the photo-etching machine, and the second standard lens is integrated on a silicon chip stage; when in measurement, the silicon chip stage and thereticle mask stage are moved to the measuring position for measuring and correcting the wave aberration of full view field of the projection objective in the photo-etching machine. The field measurement device has higher absolute measuring accuracy, is suitable for the field measurement of the wave aberration of the projection objective in the photo-etching machine, reduces the cost, the volume and the weight of the device, and is convenient for integration.

Description

An on-site measurement device for wave aberration of projection objective lens of lithography machine technical field The invention relates to a device for on-site measurement of the optical performance of a projection optical system, in particular to an on-site measurement device for the wave aberration of a projection objective lens of a lithography machine, belonging to the technical field of optical measurement. Background technique In the manufacturing process of large-scale integrated circuits, a photolithography machine with a projection exposure device is usually used to reduce and project the pattern on the mask on a silicon wafer coated with photoresist through a projection objective lens. At present, ArF lithography technology, the mainstream technology of lithography equipment, has been developed to a technology node below 65nm. In order to meet the requirements of low process factor ArF lithography technology feature size control, the wave aberration of high nu...

AI Technical Summary

Problems solved by technology

1) The Shack-Hartmann image sensor requires an incident parallel light beam, so a collimator with high numerical aperture matching the numerical aperture of the projection objective lens to be tested is required. The increase in the numerical aperture of the projection objective lens will inevitably lead to an increase in the aperture and number of collimator objective lenses. This increases the cost, increases the volume of the device, and makes it difficult to integrate;

2) The host of the device is integrated on the silicon wafer stage. For the wave aberration measurement of the immersion lithography projection objective lens, an immersion collimation objective lens is required, and the engineering difficulty of switching between the measurement position and the exposure position increases;

3) The device uses the pinhole on the mask table to select and measure the field of view point and filter to eliminate the wave surface error of the illumination system, and the device needs to deviate the pinhole in front of the collimating objective lens from the mirror surface of the projection object when calibrating the system error, and again Filtering is performed to generate spherical waves to calibrate the system error of the measurement device. After two filterings, the transmittance of the system decreases. As the numerical aperture of the projection objective lens increases, the pinhole size becomes smaller and smaller, which further reduces the transmittance. , will affect the measurement accuracy

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