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CN-121985812-A - Interconnect structure and method of forming the same

CN121985812ACN 121985812 ACN121985812 ACN 121985812ACN-121985812-A

Abstract

The invention provides an interconnection structure and a forming method thereof, and belongs to the field of semiconductors. The interconnection structure comprises a substrate, a blocking layer, an adhesive layer and an adhesive layer, wherein a groove is formed on the substrate, the blocking layer is formed on the inner wall and the bottom of the groove, the adhesive layer is formed on the inner wall and the bottom of the blocking layer, the adhesive layer is doped with metal, and the groove is filled with the adhesive layer. According to the invention, the Ru film is doped with the metal Sn, so that the Ru film has a very high melting point, has small mutual solubility with copper, has excellent wettability and adhesion, and can be directly electroplated with copper. The barrier layers of Ru and TaN materials are combined, so that the Cu-based composite material has excellent diffusion barrier properties on Cu and can keep good adhesion of Cu on Ru. In addition, the Ru film is doped with metal Sn, trace Sn doping can damage the lattice continuity of Ru, grains are refined, a finer and disordered grain structure can reduce the rapid diffusion path of copper along a grain boundary, so that the barrier performance is improved, and the reliability of an interconnection structure is effectively improved.

Inventors

  • Ran Qiuju
  • LI YECHAO
  • ZHANG KE

Assignees

  • 重庆芯联微电子有限公司

Dates

Publication Date
20260505
Application Date
20251224

Claims (10)

  1. 1. An interconnect structure, comprising: A substrate formed with a trench; the barrier layer is formed on the inner wall and the bottom of the groove; the bonding layer is formed on the inner wall and the bottom of the barrier layer and doped; And metal filled in the groove.
  2. 2. The interconnect structure of claim 1, wherein the material of the barrier layer comprises tantalum nitride and the barrier layer has a thickness of 2nm to 3nm.
  3. 3. The interconnect structure of claim 1, wherein the material of the adhesion layer comprises ruthenium, the doped element in the adhesion layer comprises tin, and the thickness of the adhesion layer is 2nm to 3nm.
  4. 4. An interconnect structure in accordance with claim 3 wherein a PVD process is used to form a bonding layer and to dope tin into the bonding layer.
  5. 5. The interconnect structure of claim 1 wherein the material of the tie layer comprises ruthenium, and wherein the atomic percent of tin in the tie layer is less than 5%.
  6. 6. A method of forming an interconnect structure, comprising: Providing a substrate; forming a trench in the substrate; forming a barrier layer on the inner wall and the bottom of the groove; forming a bonding layer on the inner wall and the bottom of the barrier layer; doping the adhesive layer; Forming a metal seed layer on the surface of the bonding layer; And filling metal in the groove by adopting an electroplating process.
  7. 7. The method of forming an interconnect structure of claim 6, wherein the material of the barrier layer comprises tantalum nitride and the thickness of the barrier layer is 2nm to 3nm.
  8. 8. The method for forming an interconnection structure according to claim 6, wherein the element doped in the adhesion layer is tin, and the thickness of the adhesion layer is 2 nm-3 nm.
  9. 9. The method of forming an interconnect structure according to claim 6, wherein tin tetrachloride is introduced into the process chamber, the adhesive layer is doped, the flow rate of the tin tetrachloride is 5 sccm-20 sccm, the power is 150W, and the gas pressure is 0.1 torr-1 torr.
  10. 10. The method of forming an interconnect structure of claim 6, wherein the material of the adhesion layer comprises ruthenium, and wherein the atomic percent of Sn in the adhesion layer is less than 5%.

Description

Interconnect structure and method of forming the same Technical Field The present disclosure relates to semiconductor technology, and more particularly, to an interconnect structure and a method for forming the same. Background As the size of integrated circuit devices continues to shrink, interconnect delay becomes increasingly a bottleneck that limits the development of integrated circuits. When the process node reaches 40nm or below, a discontinuous film is easily formed by a Ta/TaN double-layer structure diffusion barrier layer and a copper seed crystal layer which are conventionally prepared in an interconnection process, so that coverage rate is reduced, and the structure and stability of a device are affected. In order to reduce the resistance of the interconnect lines. The thicknesses of the diffusion barrier and seed layers must be reduced while maintaining device performance, and both must have very good step coverage in high aspect ratio structures. It should be noted that the information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. Disclosure of Invention The invention aims to provide an interconnection structure and a forming method thereof, which are used for solving the problem that the coverage rate of a barrier layer is reduced due to the fact that a discontinuous film is formed between the barrier layer and a metal seed layer of the interconnection structure, so that the structure and the stability of a device are affected. In order to solve the above technical problems, the present invention provides an interconnection structure, including: A substrate formed with a trench; the barrier layer is formed on the inner wall and the bottom of the groove; the bonding layer is formed on the inner wall and the bottom of the barrier layer and doped; And metal filled in the groove. Preferably, the material of the barrier layer comprises tantalum nitride, and the thickness of the barrier layer is 2 nm-3 nm. Preferably, the material of the bonding layer comprises ruthenium, the doped element in the bonding layer comprises tin, and the thickness of the bonding layer is 2 nm-3 nm. Preferably, the bonding layer is formed using a PVD process and tin is doped in the bonding layer. Preferably, the material of the bonding layer comprises ruthenium, and the atomic percentage of tin in the bonding layer is less than 5%. Based on the same inventive concept, the invention also provides an interconnection structure forming method, comprising the following steps: Providing a substrate; forming a trench in the substrate; forming a barrier layer on the inner wall and the bottom of the groove; forming a bonding layer on the inner wall and the bottom of the barrier layer; doping the adhesive layer; Forming a metal seed layer on the surface of the bonding layer; And filling metal in the groove by adopting an electroplating process. Preferably, the material of the barrier layer comprises tantalum nitride, and the thickness of the barrier layer is 2 nm-3 nm. Preferably, the doped element in the bonding layer is tin, and the thickness of the bonding layer is 2 nm-3 nm. Preferably, tin tetrachloride is introduced into the process cavity, the bonding layer is doped, the flow of the tin tetrachloride is 5 sccm-20 sccm, the power is 150W, and the air pressure is 0.1 Torr-1 Torr. Preferably, the material of the bonding layer comprises ruthenium, and the atomic percentage of Sn in the bonding layer is less than 5%. Compared with the prior art, the interconnection structure has the following advantages: According to the invention, by doping the bonding layer and doping metal Sn in the Ru film, ru has a very high melting point, so that the Ru film has small mutual solubility with copper and excellent wettability and adhesion, and can be directly electroplated with copper. The barrier layers of Ru and TaN materials are combined, so that the Cu-based composite material has excellent diffusion barrier properties on Cu and can keep good adhesion of Cu on Ru. In addition, the Ru film is doped with metal Sn, trace Sn doping can damage the lattice continuity of Ru, grains are refined, a finer and disordered grain structure can reduce the rapid diffusion path of copper along a grain boundary, so that the barrier performance is improved, and the reliability of an interconnection structure is effectively improved. In addition, the thickness of the blocking layer is 2-3 nm, the thickness of the bonding layer is only 2-3 nm, and the thicknesses of the blocking layer and the double-structure layer of the bonding layer are thinner, so that the resistance of the interconnection structure can be reduced. Therefore, the interconnect structure disclosed in this embodiment can reduce the resistance of the interconnec