Aligning mark used for photolithography equipment aligning system and its use method

Abstract

The present invention provides an aligning mark which is used for the aligning system of the photo-etching device and a using method thereof. The aligning mark comprising at least three groups of raster with different periods is used. The + / -1 grade diffraction lights of three groups of raster are used in the aligning process. Two large-period raster in three groups of raster are used for coarse alignment. A small-period raster is used for refined alignment. The alignment position error caused by the asymmetrical deformation of the aligning mark is reduced. The small period raster and the large period raster are spatially staggered. The corresponding interface images are spatially divided in the image surface. The crosstalk problem of signal is effectively settled. The energy usage of light source is increased. The intensity of aligning signal and the dynamic range of detection are facilitated to increase.

Description

technical field [0001] The invention relates to photolithographic equipment in the field of integrated circuit or other micro-device manufacturing, in particular to alignment marks of an alignment system. 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 t...

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 (2) Chinese invention patent, publication number: 200710044152.1, title of invention: an alignment system for lithography equipment), the alignment system uses a three-period phase The grating only uses the first-order diffracted light of these three periods as the alignment signal, which can achieve a large capture range and high alignment accuracy, and only uses the first-order diffracted light of each period to obtain a stronger signal strength , improve the signal-to-noise ratio of the system, and do not need to use adjustment devices such as wedges to separate multi-channel high-order diffraction components, simplifying the optical path design and debugging difficulty, but the alignment marks in the alignment system are lined up on the silicon wafer and the reference board distribution, which reduces the utilization rate of the light source, 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 scanning signal. Crosstalk problem, which is not conducive to the alignment of lithography equipment

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