Implementation method of self-alignment side wall process core layer

Abstract

The invention provides an implementation method of a self-alignment side wall process core layer. The method comprises steps that a substrate is provided; a sacrificial layer and a core layer are formed on the substrate; the core layer is etched to form a core mold with a large upper part, a small lower part and a smooth surface; side walls located on the two sides of the core mold are formed; thesacrificial layer and a part of the substrate are etched by taking side walls as masks, and a plurality of grooves with the same depth are formed in the etched substrate. The implementation method ofthe self-alignment side wall process core layer is advantaged in that a top end of the formed core mold is flat and free of fillets, side walls on two sides of the core mold are equal in distance, finally the depths of grooves formed by etching the substrate with the side walls as masks are consistent, and a problem that in the prior art, the depths of finally-formed grooves are inconsistent is solved.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for realizing a core layer of a self-aligned sidewall process. Background technique [0002] As the process nodes of semiconductor manufacturing continue to advance, the critical dimensions continue to shrink, which has exceeded the physical limit of the current mainstream lithography process. In the prior art, a self-aligned double patterning process (Self-aligned Double Patterning, SADP) is generally used. In the SADP process, in order to facilitate the subsequent etching process, it is required that the side profile of the spacer used as the hard mask should be as vertical as possible to the wafer surface. This requires that the shape of the top of the core mold (core) of the sidewall be as vertical as possible to the surface of the wafer to avoid "rounding" shape (rounding). In the current mainstream SADP process, a sacrificial layer and a core layer are seq...

AI Technical Summary

Problems solved by technology

In the current mainstream SADP process, a sacrificial layer and a core layer are sequentially formed on the substrate, a core mold is formed by dry etching of photoresist, and then side walls on both sides of the core mold are formed, and the side walls are used as a mask to etch The sacrificial layer and the substrate form multiple grooves, and the top of the mandrel formed by etching in the prior art has rounded corners, that is, the surface of the mandrel is not flat, and the rounded corners of the mandrel lead to uneven gaps between the side walls formed later. Equal, the depth of the groove formed after etching the substrate with the sidewall as a mask is inconsistent

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