CN-122028724-A - Interconnection structure manufacturing method and semiconductor structure

CN122028724ACN 122028724 ACN122028724 ACN 122028724ACN-122028724-A

Abstract

The application discloses a manufacturing method of an interconnection structure and a semiconductor structure, which comprise the steps of forming a dielectric layer on a substrate, forming a through hole with the bottom connected with the substrate on the dielectric layer, performing first treatment on the inner wall of the through hole by using nitrogen free radicals excited by metastable particles to modify the surface of the low dielectric constant material on the inner wall, forming a tantalum layer on the inner wall after surface modification, and filling metal electrically connected with the substrate in the through hole inside the tantalum layer. The application can enhance the adhesiveness of the low dielectric constant material on the surface of the inner wall and the diffusion resistance of the interface, improve the deposition quality of the tantalum layer and the metal, and effectively reduce the specific gravity of the resistance of the diffusion barrier layer in the whole through hole, thereby reducing the contact resistance and RC delay of the rear section.

Inventors

WANG SHIJING
WANG ZHAOXIANG
LIANG JIE
LI JIAN
ZHANG MINGYU
YANG WENJI

Assignees

上海邦芯半导体科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260407

Claims (10)

1. A method of fabricating an interconnect structure, comprising: Providing a substrate; forming a dielectric layer on the substrate, wherein the material of the dielectric layer comprises a low dielectric constant material; forming a through hole with the bottom connected with the substrate on the dielectric layer; Performing a first treatment on the inner wall of the through hole by using nitrogen free radicals excited by metastable particles so as to modify the surface of the low dielectric constant material on the inner wall; Forming a tantalum layer on the surface-modified inner wall; and filling metal electrically connected with the substrate in the through hole inside the tantalum layer.
2. The method of fabricating an interconnect structure according to claim 1, wherein nitrogen atoms are adsorbed on the surface of the low dielectric constant material on the inner wall to form dangling bonds by performing the first treatment to optimize surface energy and improve continuity and uniformity of the tantalum layer when forming a film on the inner wall.
3. The method according to claim 1, wherein the first treatment is performed to react the nitrogen atoms with bond bonds on the surface of the low-k material on the inner wall, so as to form a nitrogen-rich surface layer on the surface of the low-k material on the inner wall, thereby blocking interface diffusion.
4. The method of claim 1, further comprising performing a second treatment on the surface of the tantalum layer to reduce the surface state density using hydrogen radicals excited by metastable particles prior to filling the metal.
5. The method of manufacturing an interconnection structure according to claim 4, wherein the nitrogen radicals are obtained by exciting nitrogen gas with helium metastable particles and filtering out charged particles therein, the hydrogen radicals are obtained by exciting hydrogen gas with helium metastable particles and filtering out charged particles therein, and the helium metastable particles are obtained by exciting helium gas and filtering out charged particles therein.
6. The method according to claim 5, wherein the first treatment is performed at a flow rate of 1000sccm to 9000sccm, a nitrogen flow rate of helium flow=1:1 to 10:1, a temperature of 50 ℃ to 200 ℃, a source power of 1w to 100w, a pressure of 10mtorr to 1000mtorr, and a time of 5s to 300s, and ion filtering is turned on and bias power is turned off.
7. The method according to claim 5, wherein argon is further added to the hydrogen gas during the second treatment, and the concentration of the hydrogen gas is adjusted.
8. The method according to claim 7, wherein the second treatment is performed at a flow rate of 1000sccm to 2000sccm, a mixed gas flow rate of hydrogen and argon gas of helium gas flow=0.1:1 to 2:1, a hydrogen gas flow rate of argon gas flow=1:1 to 1:3, a temperature of 100 ℃ to 200 ℃, a source power of 100w to 500w, a pressure of 10mtorr to 1000mtorr, a time of 5s to 300s, and ion filtration is turned on to turn off bias power.
9. The method of manufacturing an interconnect structure according to claim 1, wherein the tantalum layer is in direct contact with the low dielectric constant material, the metal is in direct contact with the tantalum layer, and/or the low dielectric constant material comprises a silicon-based low dielectric constant material, and/or the metal comprises copper.
10. A semiconductor structure obtained by the method of manufacturing an interconnect structure according to any one of claims 1-9.

Description

Interconnection structure manufacturing method and semiconductor structure Technical Field The present application relates to the field of semiconductor processing technology, and in particular, to a method for manufacturing an interconnection structure and a semiconductor structure. Background Currently, for logic back-end-of-line processes, a diffusion barrier layer in a copper (Cu) metal via typically employs a bilayer structure of tantalum nitride (TaN) and tantalum (Ta). The TaN is used for adhesion with a dielectric layer (advanced node is a low dielectric constant (LK) material and an ultra low dielectric constant (ULK) material), and the Ta is used for reducing the resistance and adhesion with Cu deposited in a through hole later, so that the diffusion barrier capability and the resistance reduction function can be achieved. However, as the line width is continuously reduced, requirements for high diffusion barrier capability, good interfacial affinity, low resistance, and high reliability are increasingly high. As the diameter size of the through hole is continuously reduced, the thickness of the whole film layer of the diffusion barrier layer adopting the combination of TaN and Ta is required to be thinner and thinner (the thickness of the diffusion barrier layer is larger and larger in proportion to the diameter of the whole Cu metal through hole, and becomes a main reason that the contact resistance and the RC delay are difficult to reduce), so that the interface affinity of the diffusion barrier layer becomes worse and worse, film pits and peeling defects tend to occur, low yield is caused, the thickness of the whole film layer of the diffusion barrier layer adopting the combination of TaN and Ta is difficult to continuously thin, the RC delay is serious, and the contact resistance of the rear section is difficult to reduce. Therefore, there is a need to develop a process that significantly ameliorates the above-mentioned problems. Disclosure of Invention The present application is directed to overcoming the above-mentioned problems occurring in the prior art and providing a method for fabricating an interconnection structure and a semiconductor structure. In order to achieve the above purpose, the technical scheme of the application is as follows: according to a first aspect of the present application, an embodiment of the present application provides a method for manufacturing an interconnection structure, including: Providing a substrate; forming a dielectric layer on the substrate, wherein the material of the dielectric layer comprises a low dielectric constant material; forming a through hole with the bottom connected with the substrate on the dielectric layer; Performing a first treatment on the inner wall of the through hole by using nitrogen free radicals excited by metastable particles so as to modify the surface of the low dielectric constant material on the inner wall; Forming a tantalum layer on the surface-modified inner wall; and filling metal electrically connected with the substrate in the through hole inside the tantalum layer. In some embodiments, nitrogen atoms are adsorbed on the surface of the low dielectric constant material on the inner wall to form dangling bonds by performing the first treatment to optimize surface energy and improve continuity and uniformity of the tantalum layer when forming a film on the inner wall. In some embodiments, the first treatment is performed to react nitrogen atoms with bond bonds on the surface of the low dielectric constant material on the inner wall, forming a nitrogen-rich surface layer on the surface of the low dielectric constant material on the inner wall to block interfacial diffusion. In some embodiments, prior to filling the metal, a second treatment of the surface of the tantalum layer with metastable particle-excited hydrogen radicals is further included to reduce the surface state density. In some embodiments, the nitrogen radicals are obtained by exciting nitrogen gas with helium metastable particles and filtering out charged particles therein, the hydrogen radicals are obtained by exciting hydrogen gas with helium metastable particles and filtering out charged particles therein, and the helium metastable particles are obtained by exciting helium gas and filtering out charged particles therein. In some embodiments, when the first treatment is performed, the flow rate of helium is 1000 sccm-9000 sccm, the flow rate of nitrogen is equal to the flow rate of helium=1:1-10:1, the temperature is 50 ℃ to 200 ℃, the source power is 1W-100W, the pressure is 10 mTorr-1000 mTorr, the time is 5 s-300 s, ion filtration is started, and the bias power is closed. In some embodiments, argon is also added to the hydrogen gas to adjust the concentration of the hydrogen gas when the second treatment is performed. In some embodiments, when the second treatment is performed, the flow rate of helium is 1000 sccm-2000 sccm, the flow rate of mixed ga