Aligning mark, alignment method and aligning system

Abstract

The present invention provides an alignment system, alignment method and alignment mark. The alignment mark comprises a long cycle fiber grating branch and a short cycle fiber grating branch. The present invention adopts an optical-path-splitting detection system, simultaneously has signal acquisition, treatment and fitting for plus or minus 1 grade diffraction light coherent imaging of the long cycle fiber grating branch and the plus or minus 1 grade diffraction light coherent imaging of the short cycle fiber grating branch which constitute a fiber grating mark, and further combines phase information of two combinations of the signals to determine the accurate alignment position. Due to only adopting the plus or minus 1 grade diffraction light coherent imaging, the present invention avoids the adoption of a space separation device with a wedge plate regulating device required by high-grade diffraction light. By adopting the short cycle fiber grating branch, the obtainment of the higher alignment accuracy can be guaranteed. The present invention avoids crosstalk phenomenon between coarse alignment signals and fine alignment signals by adopting the optical-path-splitting detection system.

Description

technical field [0001] The invention relates to an alignment system, an alignment method and an alignment mark, in particular to an alignment system, an alignment method and an alignment mark related to photolithography devices in the field of integrated circuit or other micro-device manufacturing. Background technique [0002] The photolithography apparatus in the prior art is mainly used in the manufacture of integrated circuits (ICs) or other micro devices. Through a photolithographic apparatus, multilayer masks with different mask patterns are sequentially imaged under precise alignment on a photoresist-coated wafer, such as a semiconductor wafer or an LCD panel. Lithography devices are generally divided into two categories, one is stepping lithography devices, the mask pattern is exposed and imaged on one exposure area of ​​the wafer, and then the wafer moves relative to the mask to move the next exposure area to the mask. Underneath the mask pattern and the projection...

AI Technical Summary

Problems solved by technology

The advantage of this scheme is that it can achieve automatic capture and high alignment accuracy, but the disadvantage is that it requires a special wedge adjustment device and complicated adjustment. In addition, the high-order signals in the diffracted light are weak, while this method is Higher alignment accuracy is achieved by relying on high-order signals. In practice, as the power of the reflected signal (especially the high-order signal) of the mark (especially the silicon wafer mark) is too low, it may lead to the fact that the high-order signal cannot be used in practice. sub-signal, so cannot reliably provide the highest alignment accuracy

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