Multi-time overlay method

Abstract

The invention discloses a multi-time overlay method, which belongs to the technical field of semiconductor micro-nano manufacturing, and comprises the following steps: cleaning a substrate; spin-coating an electronic resist on the substrate; performing electron beam exposure on the pattern, and meanwhile exposing the mark array near the pattern needing to be overlaid; developing the spin-coating electronic resist; etching the pattern and the mark which are overlayed for the first time at the same time; removing the electronic resist; spin-coating an electronic resist on the substrate; using the etching mark near the position needing to be overlayed in the last processing as an overlay mark, performing electron beam overlay on the pattern, and exposing the mark array at the same time; developing the spin-coating electronic resist; etching the pattern and the mark which are subjected to the last overlay at the same time; removing the electronic resist; and finishing the last time of overlay and etching. According to the method, the accumulation of two adjacent overlay deviations and the influence of the relative position deviation of the mark and the graph caused by field splicing are solved, the overlay precision is improved, and the problem that the overlay precision is influenced by the pollution of the mark can also be solved.

Description

technical field [0001] The invention belongs to the technical field of semiconductor micro-nano manufacturing, and in particular relates to a method for multiple overlaying. Background technique [0002] Electron beam lithography is an indispensable method for fabricating optical devices, novel nanodevices, quantum devices and nanoimprint templates. Alignment accuracy is an important factor, especially for those devices that require multiple overlays and require high overlay accuracy. [0003] The traditional overlay method is to first coat the positive electronic resist on the substrate and expose the mark array, develop the electronic resist and then evaporate Ti+Au by electron beam, and form the Ti+Au mark array on the substrate by peeling off the metal. The step of each overlay is to first coat the electronic resist, use the prepared Ti+Au mark array as the overlay mark for exposure, and perform subsequent etching and stripping after development. Complete the first ove...

AI Technical Summary

Problems solved by technology

[0004] Multiple overlays require multiple exposure, etching, peeling, baking and other processes on the prepared Ti+Au mark, which will inevitably damage the shape of the mark to varying degrees and affect the mark detection signal At the same time, the traditional overlay still has the accumulation of deviations between two adjacent overlays, and the field splicing causes the relative position deviation of the mark and the graphic, thus affecting the overlay accuracy.

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