Mask pattern, semiconductor structure and preparation method thereof

Abstract

The invention relates to a preparation method of a mask pattern. The preparation method comprises the following steps: forming a pattern transfer layer, an etching stop layer, a sacrificial layer and a hard mask layer which are stacked from bottom to top; patterning the hard mask layer and the sacrificial layer to obtain a sacrificial pattern which exposes the etching stop layer; forming a side wall structure on the side wall of the sacrificial pattern; removing the sacrificial pattern; forming a filling layer between the side wall structures, wherein the etching selection ratio of the side wall structures to the filling layer is greater than 100; removing the side wall structure to form an initial mask pattern; and etching the etch stop layer and the pattern transfer layer based on the initial mask pattern to transfer the pattern of the initial mask pattern to the pattern transfer layer to obtain a target mask pattern. According to the method, the risk that the side wall gap formed after the side wall is removed in the RSADP process and the gap formed by continuous etching based on the gap formed after the side wall is removed are blocked can be reduced.

Description

technical field [0001] The invention relates to the field of integrated circuit manufacturing, in particular to a mask pattern, a semiconductor structure and a preparation method thereof. Background technique [0002] With the rapid development of semiconductor storage technology, the volume of semiconductor storage products is getting smaller and smaller, but the market puts forward higher requirements for the storage capacity of semiconductor storage products. Especially for DRAM (Dynamic Random Access Memory, DRAM), how to prepare DRAM with smaller size and higher reliability is a major issue at present. [0003] In the preparation process of DRAM, a reverse self-aligned double patterning (RSADP) process is required. When using the reverse self-aligned double patterning process to prepare a mask structure, due to the continuous reduction in the volume of DRAM Small, the thickness of the oxide layer used as the side wall is small, it is easy to etch the organic material l...

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Problems solved by technology

[0003] In the preparation process of DRAM, a reverse self-aligned double patterning (RSADP) process is required. When using the reverse self-aligned double patterning process to prepare a mask structure, due to the continuous reduction in the volume of DRAM Small, the thickness of the oxide layer used as the side wall is small, it is easy to etch the organic material layer as the sacrificial pattern when removing the oxide layer, and it is easy to cause the organic material layer or the The by-products (such as polymers) generated during the etching process block the bottom of the etching trench, and the organic material layer will block the etching process, making it impossible for the subsequent process to continue to etch down, causing the etching trench at different positions to be different. inconsistent depth

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