Method for reducing polycrystalline silicon critical dimension loss caused by photoetching photoresist reworking

Abstract

The invention discloses a method for reducing polycrystalline silicon critical dimension loss caused by photoetching photoresist reworking, which comprises the steps of S1, providing a semiconductor device for polycrystalline silicon LEC etching, wherein the just preceding process of polycrystalline silicon thin film etching is completed; S2, carrying out polymer deposition; and S3, carrying out photoetching photoresist reworking, and carrying out polycrystalline silicon thin film etching to obtain a polycrystalline silicon critical dimension device meeting the process control standard. According to the method, polymer deposition is carried out on the semiconductor device which is subjected to the just preceding process of etching the polycrystalline silicon thin film, the critical dimension of a hard mask is increased, and under the condition that the pattern of the polycrystalline silicon thin film is not changed, the problem that the critical dimension of polycrystalline silicon is reduced can be effectively solved, the product yield is improved, and the production cost is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a method for reducing the loss of critical dimensions of polysilicon caused by photolithography and photoresist rework. Background technique [0002] Driven by Moore's Law, the size of the semiconductor process is gradually shrinking, and the online control is becoming more and more stringent. At the 28nm technology node, polysilicon is etched in two steps: polysilicon hard mask etching and polysilicon LEC (LEC, Litho Edgecut) etching. In this field, as everyone knows, after the first polysilicon hard mask etching is completed, the polysilicon line width has been determined; the second polysilicon LEC etching will inherit the critical dimensions of the polysilicon hard mask (CD, CriticalDimension) etch down. [0003] However, when the Q-time overtime of polysilicon LEC etching requires photolithography and photoresist rework, it is limited by the rework proc...

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Problems solved by technology

[0003] However, when the Q-time overtime of polysilicon LEC etching requires photolithography and photoresist rework, it is limited by the rework process conditions, such as dry stripping, wet cleaning and other processes, which will inevitably reduce to a certain extent. Critical Dimensions of Polysilicon Hard Mask

It is easy to understand that during the rework process, the sidewalls of the oxide layer / silicon nitride layer used as a hard mask will first be bombarded by dry stripping plasma, resulting in a loss of part of the line width; after wet cleaning It will cause some loss of line width

Therefore, in the case of photolithography and photoresist rework, the final polysilicon critical dimension will become smaller after polysilicon LEC etching, the actual impact is about 1nm, and the online measurement fluctuation of about 3sigma will directly cause yield loss

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