Method for forming first copper metal layer

Abstract

The invention relates to the field of the manufacturing of semiconductors and particularly relates to a method for forming a first copper metal layer. According to the method for forming the first copper metal layer provided by the invention, amorphous carbon is taken as a stopping layer for a grinding process in the first copper metal layer preparation process, not only can the constant thickness of a dielectric layer be ensured, also any residual can be removed easily, and further, the performance and the stability of the device are improved.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for forming a first copper metal layer. Background technique [0002] In the process of 45nm and below, in the current process of preparing the first copper metal layer, amorphous carbon (amorphous carbon) is often used as a hard mask to etch the first layer of metal trenches. After removing the above-mentioned amorphous carbon, Then fill the barrier layer of tantalum nitride / tantalum (TaN / Ta) and seed copper (Cu seed), and finally perform copper electroplating filling, and remove excess copper by chemical mechanical polishing (CMP) to form copper wiring. [0003] Figure 1-5 It is a schematic diagram of the flow structure of the traditional process for preparing the first copper metal layer in the background technology of the present invention; Figure 1-5 As shown, on the silicon wafer 11 having the underlying device structure, after the etch stop layer 12, ...

AI Technical Summary

Problems solved by technology

[0005] Finally, using a chemical mechanical polishing process (CMP) and using the remaining dielectric layer 131 as a stop layer, the excess copper 18 and the tantalum nitride / tantalum (TaN / Ta) barrier layer 17 covering the upper surface of the remaining dielectric layer 131 are removed by grinding To the upper surface of the remaining dielectric layer 131, copper wiring 181 is formed; as the size of the device becomes smaller and smaller, the barrier layer of the remaining tantalum nitride / tantalum (TaN / Ta) in direct contact with the dielectric layer and copper becomes more and more The thinner it is, the more and more difficult it is to control the above-mentioned chemical mechanical polishing process, and it often occurs that the thickness of the remaining dielectric layer 131 varies greatly due to excessive grinding, thereby affecting the performance and stability of the device.

Images