Self-aligned double patterning method

Abstract

The invention provides a self-aligned double patterning method. The method comprises the following steps of etching a second anti-reflection layer under a photoresist layer after finishing of the photoresist layer, transferring a photoresist pattern to the second anti-reflection layer firstly and then carrying out finishing on the second anti-reflection layer to transfer the pattern to a second hard mask layer to complete spindle etching. In the double patterning method, the spindle etching is a main factor to decide the final etching curvature; through twice finishing, the pattern morphologyafter spindle etching is controlled, so that the technical quality is improved when a sidewall carries out patterning in a self-aligned manner, and thus the etching curvature is improved, a problem ofdevice failure caused by poor etching curvature is reduced and the performance of the device is improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a self-aligned double patterning method. Background technique [0002] With the rapid development of semiconductor technology, the feature size of semiconductor devices is constantly shrinking, which makes the integration level of integrated circuits higher and higher, which also puts forward higher requirements for semiconductor manufacturing processes. [0003] Etching is an important process in semiconductor manufacturing. It is the process of transferring the pattern on the mask plate to the material layer. With the continuous reduction of feature size, especially when entering the 20nm and below processes, the photolithography process is due to The existence of the wavelength limit makes the etching process encounter a bottleneck, and the etching of smaller-sized trenches cannot be provided. [0004] At present, the industry has proposed a self-aligned double patt...

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Problems solved by technology

However, after this etching, there will be a problem of bad etching tortuosity (wiggling), that is, there is a curvature in the shape of the etched groove, which will lead to the problem of device failure, especially in the metal interconnection line. process, will cause a short circuit between adjacent copper wires

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