Method for measuring etching deviation of hard mask layer in self-alignment imaging process

Abstract

The invention provides a method for measuring the etching deviation of a shear layer in a self-alignment imaging process, and the method comprises the steps: designing a test pattern, and a main layout comprises sacrificial layer patterns which are distributed at equal intervals in the X direction and are sequentially distributed at fixed offset in the Y direction, and a plurality of rows of shear layer patterns which are distributed at equal intervals in the X and Y directions. And the period of two adjacent sacrificial layer patterns in each column in the Y direction is consistent with the period of the shear layer pattern. And transferring the test pattern to a photomask, carrying out a series of processes such as photoetching and etching, carrying out detection by using a large-field detection tool, and determining the boundary of the etched pattern through the fin structure which is just completely cut off and the position of the fin structure which is just cut off. According to the method, the boundary of the shearing layer AEI CD is accurately determined, so that the etching deviation is determined, reference is provided for adjustment of an optical proximity effect correction / photoetching / etching process, the accuracy of process correction and adjustment is improved, and defects are reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for measuring the etching deviation of a hard mask layer in a self-aligned imaging process. Background technique [0002] In the FinFet (fin transistor) process, the SADP (Self-Aligned Dual Imaging) process is used to define the overall fin, and then the redundant fin is removed by shearing layers parallel to the fin and perpendicular to the fin to define the active Area. For shear layers parallel to the fin, the ideal is to etch away the excess integral fin without damaging the upper and lower fins. like figure 1 , are the overall fin and the active area defined by the shear layer, respectively, the dotted line marked area is the shear layer area parallel to the fin, and the fin near the boundary of the shear layer has obvious fin damage. [0003] From the layout file to the final active area, through OPC (Optical Proximity Effect) correction, photolithography...

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Problems solved by technology

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for measuring the etching deviation of the hard mask layer in the self-aligned imaging process, which is used to solve the problem of the three-dimensional structure of the bottom layer in the prior art. The shear layer of fin does not leave imprints on the bottom layer after the etching process, so it is impossible to directly measure the critical dimensions after development, and it is impossible to obtain the etching deviation and its impact on fin damage, and it is impossible to simulate the chip The problem of real etching behavior in

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