Photoetching alignment mark for measuring inclination angle and rotation angle and alignment method

Abstract

The invention discloses a photoetching alignment mark for measuring an inclination angle and a rotation angle and an alignment method. The photoetching alignment mark comprises a silicon wafer mark and a mask mark, the outer contour sizes of the two marks are the same, each mark is formed by arranging five squares with the same side length in a cross shape, and coarse alignment of two planes of a silicon wafer and a mask can be completed by overlapping the outer contours; unique pattern structures and grating structures are designed in the silicon wafer mark and the mask mark, and quantitative detection of inclination angles and rotation angles of two planes of the silicon wafer and the mask is realized by observing patterns in the mask mark and the silicon wafer mark after coarse alignment and moire fringes generated by gratings. In order to solve the problems that in the prior art, a small offset capturing method is complex, and an inclination angle and a rotation angle exist between two planes of a mask and a silicon wafer, a unique photoetching alignment mark is designed, a corresponding photoetching alignment method is optimized, and the method has the advantages of being simple in alignment process, good in alignment effect and high in alignment precision.

Description

technical field [0001] The invention relates to the field of photolithography, in particular to a photolithographic alignment mark and an alignment method for measuring inclination angles and rotation angles. Background technique [0002] Lithography is a key common technology in the field of electronic information, and it is also one of the high-tech fields and "stuck neck" technologies that the country focuses on. It is widely used in military and civilian fields such as integrated circuits, communication equipment, missile radar, biomedicine, and artificial satellites. [0003] With the continuous development and progress of various technologies, the requirements for lithography resolution are increasing day by day (even reaching the order of several nanometers), and the existing lithography technology is limited by factors such as the wavelength of the light source and the numerical aperture of the lens, which can no longer meet the requirements. Requirements, therefore ...

AI Technical Summary

Problems solved by technology

However, the nanolithography system requires extremely high alignment accuracy. At this time, the influence of the inclination and rotation angle between the two planes on the alignment accuracy becomes more obvious and serious, which cannot be ignored

However, the detection and correction of small offsets in existing alignment methods requires a relatively complex detection method, which has the disadvantages of cumbersome steps, low efficiency, and high cost.

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