Method of forming contact plugs

Abstract

A formation method of a contact plug comprises the steps of providing a substrate; forming an interlayer dielectric layer on the substrate; forming a high K dielectric layer on the interlayer dielectric layer; etching the high K dielectric layer and the interlayer dielectric layer orderly until the substrate is exposed to form a contact hole; continuously etching the high K dielectric layer along the contact hole until the diameter of the contact hole located at the high K dielectric layer is increased; adopting a conductive material to fill the contact hole. The formation method of the contact plug enables the formation difficulty of the contact plug to be reduced and also the quality of the formed contact plug to be improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a contact plug. Background technique [0002] In the integrated circuit manufacturing process, in order to connect semiconductor devices such as CMOS on the semiconductor substrate with the upper metal interconnection layer, a metal pre-dielectric layer between the first metal interconnection layer and the semiconductor device layer ( Inter-metal Dielectric, IMD) etch to form a contact hole, and then fill the contact hole with (metal) conductive material such as tungsten, aluminum or copper to form a contact plug (contact). [0003] Please refer to figure 1 , the conventional method for forming a contact plug generally includes: providing a substrate 100 with a MOS transistor on the substrate 100, the MOS transistor includes a gate structure 101, sidewalls 102 positioned on the sides of the gate structure, and a metal layer in the substrate below t...

AI Technical Summary

Problems solved by technology

However, forming a contact hole 111 with a large depth and a relatively steep inner wall is undoubtedly a major challenge in the industry. What's more, even if the contact hole 111 with a large depth and a steep inner wall is successfully formed, it is extremely difficult to fill. Some methods have been difficult to fill it well, resulting in the performance degradation of the final contact plug

[0006] For this reason, a new method of forming contact plugs is needed to solve the problem that contact holes are difficult to form in the existing methods, and even after being formed, it is still difficult to fill them well, resulting in the degradation of the performance of contact plugs.

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