Method for etching through hole

Abstract

The invention provides a method for etching a through hole, and the method comprises the following steps of: coating photoresist on the surfaces of a semiconductor substrate, an etching cease layer and an interlamination dielectric layer which are sequentially overlapped from bottom to top, and placing into a reaction cavity, wherein the semiconductor substrate contains a copper metal layer; etching the photoresist and an interlayer dielectric; and detecting that the interlamination dielectric layer is completely etched through a terminal detection system, regulating bias voltage power to zero, and accessing a mixed gas of a fluorine-containing gas and an auxiliary gas to etch the etching cease layer till the etching cease layer positioned on the surface of the copper metal layer is removed. According to the invention, the mixed gas formed from a large quantity of auxiliary gases and a small quantity of fluorine-containing gases is adopted as an etching gas in the etching process, the fluorine-containing gases play main etching roles, and the auxiliary gases achieve the purposes of removing polymers positioned on an etched side wall and diluting gases and matched with zero-bias power, in such a way, the phenomenon of nonuniform etching in the etching process can be effectively prevented, and therefore the etching velocity and the efficiency of an etching process are increased.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a through hole etching method. Background technique [0002] Since the copper process was used to replace the aluminum process in the mid-1990s, the advantages of the copper process have remained basically unchanged: copper has low resistance and good electrical conductivity. Even stronger current carrying capacity can be made smaller and denser at the same time. In addition, copper wires can be made thinner, thereby reducing mutual interference between adjacent wires. [0003] The copper process uses an embedded process to obtain patterned wires, and the upper and lower copper wires are connected through micro-vias. In order to get these vias, another layer of photolithography and etching steps are required, and the way the industry usually handles it is to planarize and clean the copper metal, and then deposit a layer of silicon nitride or silicon carbide ...

AI Technical Summary

Problems solved by technology

[0009] In view of the above existing problems, the purpose of the present invention is to avoid the exposure of copper metal caused by uneven etching during the process of etching the etch stop layer, thereby avoiding the pollution of the reaction chamber caused by the exposure of copper metal , and improve the problem of large fluctuations in etching rate and instability of etching process

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