Alignment mark and its imaging optical system and imaging method

Abstract

This invention relates to a sort of alignment mark, and this alignment mark is the multiply periodic grating configuration. It consists of several group of the different periodic grating. This invention also offers a sort of imaging optical system of this alignment mark, and the alignment mark from the picture by this optical system, and it consists of this cohere imaging system at least. The first imaging system consists of frontal group lens, the first space wave filter, and the first back group lens. The second consists of the frontal group lens, the second space wave filter, and the secondback group lens. This invention also offers a sort of the method which adopts this optical system to produce the picture to the alignment mark. This method consists of this approach: Offer and transfer the laser illuminating beam of light, and irradiate it to the alignment mark. Adopt the diffraction light and the reflex of the alignment mark. The diffraction light produces the picture by the first coheres imaging system and the second cohere imaging system of the optical system. This invention advances the detecting precision of the alignment mark availably.

Description

technical field

[0001] The present invention relates to a lithography device in the field of integrated circuit IC or other micro device manufacturing, and relates to an alignment mark, an optical system for imaging the alignment mark and an imaging method. Background technique

[0002] The photolithography apparatus in the prior art is mainly used in the manufacture of integrated circuits (ICs) or other micro devices. With a photolithographic apparatus, multilayer masks with different mask patterns are sequentially imaged in 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 a stepping lithography device, 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 pattern and under the projection objective, the mask pattern is again exposed on another expos...

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