Alignment system and method for lithographic apparatus

Abstract

The invention discloses an aligning system and an aligning method for a photolithographic device. The aligning system is characterized by includes a light source module which is used for providing an illuminating beam; an illumination module and a digital micro-mirror device, wherein the illuminating beam passes through the illumination module and the digital micro-mirror apparatus, and the digital micro-mirror apparatus is used for forming a reference optical grating which is matched with an alignment mark; an imaging module which allows the illuminating beam, after passing through the digital micro-mirror device, to be incident on an alignment mark surface through the imaging module and the reference optical grating. The reference optical grating, after being modulated by the alignment mark, enables the illuminating beam to be interfered to form moire fringe. The imaging module collects interfered light carrying a light intensity signal of the moire fringe. The aligning system also includes a detection module which detects the light intensity signal of the moire fringe and determines information of an alignment position according to the light intensity signal.

Description

technical field [0001] The invention relates to the field of integrated circuit equipment manufacturing, in particular to an alignment system and method for photolithography equipment. Background technique [0002] At present, the optical lithography technology has reached the 22nm process node, which puts forward higher requirements for the overlay accuracy. As one of the core components of the projection lithography machine, the alignment accuracy of the silicon wafer and the mask alignment subsystem is the most important factor. The key factor of overlay accuracy, and the alignment speed, efficiency and the flexibility of alignment technology will directly affect another key indicator of the lithography machine - the productivity. [0003] The so-called alignment refers to the establishment of a precise relative positional relationship between the mask and the silicon wafer. Alignment technology generally includes four parts: illumination system, imaging system, marking,...

AI Technical Summary

Problems solved by technology

[0004] However, there are many types of grating marks used for alignment systems, such as XPA, SPM, etc. Different lithography machine manufacturers, different product models, different alignment systems, and different alignment marks are not compatible with each other, and Once installed, such as a reference grating, even if there are installation or manufacturing errors, it cannot be changed, lacking the necessary flexibility and compatibility

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