Etching method of metal interconnection structure

Abstract

The invention discloses an etching method of a metal interconnection structure. The method comprises the following steps: covering a photoresist on other areas except a target area of a second hard mask layer through a photoetching process, forming the second hard mask layer on a first hard mask layer, forming the first hard mask layer on a metal layer, and forming the metal layer on a dielectriclayer and a metal connecting line formed in the dielectric layer; trimming the photoresist, so that the photoresist is thinned; carrying out etching to remove the second hard mask layer and the firsthard mask layer in the target area until the metal layer in the target area is exposed; and removing the photoresist. According to the invention, before the hard mask layer of the metal interconnection structure is etched, the hard mask layer is etched, the photoresist is trimmed, the critical size of the photoresist can be reduced in the initial process of subsequent etching, meanwhile, the sizeof the bottom of the photoresist can be reduced, and the roughness of the side wall of the photoresist is reduced, so that the subsequent etched structure has good morphology, and the stability and the manufacturing yield of the device are improved.

Description

technical field [0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to an etching method of a metal interconnection structure. Background technique [0002] In the back end of line (BEOL) process of semiconductor manufacturing, the damascene process is usually used. This process is to etch the metal connection trenches on the dielectric layer, fill the metal, and then planarize the metal, repeat The above processes until the metal interconnection structure is formed. [0003] refer to figure 1 , which shows a schematic cross-sectional view of covering the photoresist on the hard mask layer during the etching process of the metal interconnection structure provided in the related art; refer to figure 2 , which shows a schematic cross-sectional view after etching the hard mask layer during the etching process of the metal interconnection structure provided in the related art. [0004] like figure 1 As shown, a met...

AI Technical Summary

Problems solved by technology

[0007] The present application provides an etching method for a metal interconnection structure, which can solve the problems of relatively high prob

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