Aligning device for photolithography equipment

Abstract

Disclosed is an aligning device and photolithography equipment adopting the aligning device. The aligning device comprises a light source, a target grating, a 4F optical system, a diffraction order selecting component arranged on a spectrum plane between two lenses of the 4F optical system, a silicon wafer provided with an alignment mark, a photoelectric detector, and an alignment signal processing module. Light from the light source diffracts after illuminating the target grating and generates diffracted beams, and the diffracted beams irradiate the 4F optical system. The diffraction order selecting component selects diffraction orders to enable the size of an interference fringe cycle generated by the diffracted beams to correspond to that of a grating cycle. Diffracted beams of each order coherently image on the corresponding alignment marks of the silicon wafer after going through the 4F optical system. Scanning of an interference image and alignment marks is realized through a manner that a silicon wafer platform drives the silicon wafer to move. The photoelectric detector detects optical signals obtained through scanning and the alignment signal processing module calculates an alignment position according to the alignment signals.

Description

technical field [0001] The invention relates to the field of lithography, and in particular to an alignment device and an alignment method for lithography equipment. Background technique [0002] The lithography equipment in the prior art is mainly used in the manufacture of integrated circuits (ICs) or other micro devices. Through photolithography equipment, multi-layer masks with different mask patterns are sequentially exposed and imaged on a silicon wafer coated with photoresist under precise alignment. The current lithography equipment is roughly divided into two categories, one is stepping lithography equipment, the mask pattern is exposed and imaged on one exposure area of ​​the silicon wafer, and then the silicon wafer moves relative to the mask to move the next exposure area Go to the mask pattern and under the projection objective lens, again expose the mask pattern on another exposed area of ​​the silicon wafer, and repeat this process until all exposed areas on ...

AI Technical Summary

Problems solved by technology

However, when using a wedge array, the requirements for the surface shape and wedge angle consistency of the two wedges with the same positive and negative orders of refraction are very high; and the requirements for the manufacturing, assembly and adjustment of the wedge plate group are also very high. It is difficult and expensive to realize the project

[0008] Another prior art situation (see Chinese invention patent application: 200710044152.1, title of invention: an alignment system for lithography equipment), this alignment system uses a three-period phase grating with a combination of thick and thin, only using this The first-order diffracted light of three periods is used as the alignment signal, which can achieve a large capture range and high alignment accuracy. Only the first-order diffracted light of each period can be used to obtain a stronger signal strength and improve the system signal-to-noise In comparison, there is no need to use adjustment devices such as wedges to separate multi-channel high-order diffraction components, which simplifies the optical path design and debugging difficulty, but the alignment marks in the alignment system are arranged in a line on the silicon wafer and the reference plate, reducing the light source. The utilization rate, and this arrangement mode scans the corresponding reference grating when each group of grating images of the alignment mark scans the corresponding reference grating, and the grating images of different periods scan a reference grating at the same time, which will cause the crosstalk problem of the scanning signal, which is not conducive to Alignment of lithographic equipment

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