Copper interconnection structure and method for manufacturing same

Abstract

The invention provides a copper interconnection structure and a method for manufacturing the same. The copper interconnection structure comprises a semiconductor substrate, a first interlayer dielectric layer disposed on the semiconductor substrate, a copper plug running through the first interlayer dielectric layer, a second interlayer dielectric layer disposed on the first interlayer dielectric layer, and a copper interconnection wire running through the second interlayer dielectric layer. A first protective layer is arranged between the first interlayer dielectric layer and the copper interconnection wire, and a second protective layer is arranged between the second interlayer dielectric layer and the copper interconnection wire. According to the copper interconnection structure provided by the invention, as the first protective layer is arranged between the first interlayer dielectric layer and the copper interconnection wire and the second protective layer is arranged between the second interlayer dielectric layer and the copper interconnection wire, direct contact between the copper interconnection wire and the first interlayer dielectric layer and between the copper interconnection wire and the second interlayer dielectric layer is avoided, and the first interlayer dielectric layer and the second interlayer dielectric layer are prevented from being fractured by the copper interconnection wire.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a copper interconnection structure and a manufacturing method of the copper interconnection structure. Background technique [0002] With the development of semiconductor technology, the integration level of VLSI chips has reached hundreds of millions or even billions of devices, and multi-layer metal interconnection technology with more than two layers is widely used. The metal interconnection layer includes a metal interconnection structure (the metal interconnection structure includes metal interconnection lines and metal plugs) and an inter-layer dielectric layer (Inter-layer dielectric, ILD). The fabrication method of the metal interconnection layer generally includes manufacturing trenches and vias in the interlayer dielectric layer, and then depositing metal in the trenches and vias, and the deposited metal forms the metal interconnection structure. Because copper has good c...

AI Technical Summary

Problems solved by technology

[0004] However, in metal interconnect structures formed by existing methods, such as Figure 4 As shown, the contact area between the interlayer dielectric layer 101 and the copper interconnection 113 is relatively large, because the mechanical strength of the interlayer dielectric layer 101 is relatively small, and the density of copper is relatively large, so the copper interconnection 113 is easy to The interlayer medium layer 101 is fractured, so that cracks (Crack) 117 appear in the interlayer medium layer 101

Once cracks 117 appear in the interlayer dielectric layer 101, the reliability of the entire semiconductor structure cannot be guaranteed, and the interlayer dielectric layer 101 is very likely to crack during subsequent processing, which may cause the entire semiconductor structure to be scrapped.

What needs to be emphasized is that since the thickness of the interlayer dielectric layer corresponding to the interconnection structure of the top layer is much larger than the thickness of the interlayer dielectric layer corresponding to other interconnection structures, the copper interconnection lines in the interconnection structure of the top layer are much larger than those of other interconnection structures. The copper interconnects in the interconnect structure are much thicker, that is, the volume of the copper interconnects will be larger, so it can be seen that the copper interconnects on the top layer are more likely to cause cracks in the interlayer dielectric layer

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