Photolithography method capable of reducing line roughness

Abstract

The invention discloses a photolithography method capable of reducing line roughness. The method comprises the following steps: forming a structural material layer and hard mask layers on a substrate; forming electronic beam photoresist on the hard mask layers, then forming electronic beam photoresist graphics by executing electronic beam overexposure, wherein the exposure dose is increased so as to improve the roughness; taking the electronic beam photoresist graphics as the mask, forming hard mask graphics by etching; taking the hard mask graphics as the mask, and etching the structural material layer so as to formed the needed fine lines. In this method, a plurality of hard mask layers made of different materials is adopted and photolithography conditions are reasonably adjusted at the same time so as to prevent the roughness degree of the sidewall of the electronic beam photoresist from being transmitted to the structural material layer under the hard mask layers, thus the line roughness is effectively reduced, the technology stability is improved, and the fluctuation of device performance is reduced.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing, and more specifically, relates to a photolithographic method for reducing line roughness by using electron beam overexposure technology. Background technique [0002] With the gradual reduction of VLSI feature size, the technical limit of ordinary optical exposure has come after entering the 22nm technology generation in the manufacturing method of semiconductor devices. At present, after the 45nm process node, i193nm immersion lithography technology combined with double exposure and double etching technology is generally used to prepare smaller lines. Fine patterning at nodes below 22nm typically requires exposure and lithography using e-beam or EUV. [0003] Regarding EUV lithography technology, it is still in the research and development stage, and there are still several key technologies that need to be overcome and improved, and it cannot be applied to large-sca...

AI Technical Summary

Problems solved by technology

The thinner photoresist can expose smaller lines. However, due to the insufficient selectivity of the etching process, such thin photoresist will often be lost early in the etching process, thus failing to obtain the desired lines, and there is a serious line roughness problem

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