CN116031204A - Method for forming metal interconnection structure - Google Patents
Method for forming metal interconnection structure Download PDFInfo
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- CN116031204A CN116031204A CN202310108882.2A CN202310108882A CN116031204A CN 116031204 A CN116031204 A CN 116031204A CN 202310108882 A CN202310108882 A CN 202310108882A CN 116031204 A CN116031204 A CN 116031204A
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Abstract
The application discloses a method for forming a metal interconnection structure, which comprises the following steps: forming a first barrier layer on the surfaces of the dielectric layer and the through hole, wherein the through hole is formed in the dielectric layer and is opened on the surface of the dielectric layer; performing reverse sputtering, and trimming a protrusion structure formed at the opening of the first barrier layer; and forming a second barrier layer on the surface of the first barrier layer. According to the method, after the first barrier layer of the contact hole is formed in the forming process of the metal interconnection structure, the protruding structure formed at the opening of the through hole by the first barrier layer is trimmed through reverse sputtering, so that the opening of the through hole is enlarged, the subsequent metal layer is filled, the generation of filling gaps is reduced to a certain extent, and the reliability and the yield of the device are improved.
Description
Technical Field
The application relates to the technical field of semiconductor manufacturing, in particular to a method for forming a metal interconnection structure.
Background
In a back end of line (BEOL) process of semiconductor integrated circuit fabrication, electrode extraction in the device may be achieved by forming a metal interconnect structure. Generally, a method of forming a metal interconnect structure includes: and after etching the dielectric layer to form a through hole, filling metal, flattening the metal, and repeating the process until a metal interconnection structure is formed.
However, with the progress of semiconductor manufacturing, the critical dimensions (critical dimension, CD) of the semiconductor device are also becoming smaller and smaller, and accordingly, in the process of manufacturing the metal interconnection structure, after the metal filling is performed on the via hole of the contact hole (via), there is a greater probability that the formed contact hole has void (void) defects due to the reduction of the width of the via hole, thereby reducing the reliability and yield of the device.
Disclosure of Invention
The application provides a method for forming a metal interconnection structure, which can solve the problem that the method for manufacturing the metal interconnection structure provided in the related art has a larger probability of forming void defects due to small critical size of a through hole of a formed contact hole, and comprises the following steps:
forming a first barrier layer on the surfaces of the dielectric layer and the through hole, wherein the through hole is formed in the dielectric layer and is opened on the surface of the dielectric layer;
performing reverse sputtering, and trimming a protrusion structure formed at the opening of the first barrier layer;
and forming a second barrier layer on the surface of the first barrier layer.
In some embodiments, the first barrier layer comprises a tantalum nitride layer.
In some embodiments, the forming a first barrier layer on the dielectric layer and the surface of the through hole includes:
and depositing a tantalum nitride layer on the surfaces of the dielectric layer and the through hole through a sputtering process to form the first barrier layer.
In some embodiments, the second barrier layer comprises a tantalum layer.
In some embodiments, the forming a second barrier layer on the surface of the first barrier layer includes:
depositing a first tantalum layer on the first barrier layer by a sputtering process;
performing reverse sputtering, and trimming the first tantalum layer;
and depositing a second tantalum layer through a sputtering process, wherein the second tantalum layer and the rest of the first tantalum layer form the second barrier layer.
In some embodiments, after the forming the second barrier layer on the surface of the first barrier layer, the method further includes:
forming a metal layer on the second barrier layer, wherein the metal layer fills the through hole;
and carrying out planarization treatment, and removing the first barrier layer, the second barrier layer and the metal layer in other areas outside the through hole, wherein the first barrier layer, the second barrier layer and the metal layer in the through hole form a metal connecting line.
In some embodiments, the forming a metal layer on the second barrier layer includes:
forming a copper seed layer on the second barrier layer;
and forming a metallic copper layer on the copper seed layer.
The technical scheme of the application at least comprises the following advantages:
in the forming process of the metal interconnection structure, after the first barrier layer of the contact hole is formed, the protruding structure formed at the opening of the through hole by the first barrier layer is trimmed by reverse sputtering, so that the opening of the through hole is enlarged to facilitate the filling of a subsequent metal layer, the generation of filling gaps is reduced to a certain extent, and the reliability and the yield of the device are improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method of forming a metal interconnect structure provided in one exemplary embodiment of the present application;
fig. 2 to 6 are schematic views illustrating formation of a metal interconnection structure according to an exemplary embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made apparent and complete in conjunction with the accompanying drawings, in which embodiments described are some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
In the description of the present application, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of description of the present application and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; the two components can be directly connected or indirectly connected through an intermediate medium, or can be communicated inside the two components, or can be connected wirelessly or in a wired way. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.
In addition, the technical features described below in the different embodiments of the present application may be combined with each other as long as they do not collide with each other.
Referring to fig. 1, a flowchart illustrating a method for forming a metal interconnection structure according to an exemplary embodiment of the present application is shown, and as shown in fig. 1, the method includes:
step S1, forming a first barrier layer on the surfaces of a dielectric layer and a through hole, wherein the through hole is formed in the dielectric layer and is opened on the surface of the dielectric layer.
Referring to fig. 2, a schematic cross-sectional view is shown after forming a first barrier layer. Illustratively, as shown in fig. 2, the dielectric layer 210 has a via 300 formed therein, the first barrier layer 221 may include a tantalum nitride (TaN) layer, the first barrier layer 221 may be formed by depositing a tantalum nitride layer on the surfaces of the dielectric layer 210 and the via 300 through a physical vapor deposition (physical vapor deposition, PVD) process (e.g., a sputtering process), and the first barrier layer 221 may be formed with a protrusion structure at an opening of the via 300 (as shown by a dotted line in fig. 2). Wherein, the dielectric layer 210 is an inter-level dielectric (ILD) layer of an Mth (M is a natural number, M.gtoreq.1) metal layer of the metal interconnection structure.
And S2, performing reverse sputtering, and trimming the protruding structure formed at the opening of the first barrier layer.
Referring to fig. 3, a schematic cross-sectional view of a first barrier layer after trimming the protruding structures formed at the openings by reverse sputtering is shown. Illustratively, as shown in fig. 3, after the reverse sputtering process, the protruding structure is thinned so that the opening becomes large.
And S3, forming a second barrier layer on the surface of the first barrier layer.
Illustratively, the second barrier layer may include a tantalum (Ta) layer, step S3 includes, but is not limited to: depositing a first tantalum layer on the first barrier layer by a sputtering process; performing reverse sputtering, and trimming the first tantalum layer; and depositing a second tantalum layer through a sputtering process, wherein the second tantalum layer and the rest of the first tantalum layer form a second barrier layer.
Referring to fig. 4, a schematic cross-sectional view of depositing a first tantalum layer on a first barrier layer is shown; referring to fig. 5, a schematic cross-sectional view of a first tantalum layer after trimming is performed; referring to fig. 6, a schematic cross-sectional view of depositing a second tantalum layer is shown.
As illustrated in fig. 4 to 6, the first tantalum layer 2221 may be deposited on the first barrier layer 221 by a sputtering process, the opening of the via 300 becomes large and the first tantalum layer 2221 is thinned after trimming the first tantalum layer 2221 by reverse sputtering, and the second tantalum layer 2222 is deposited by a sputtering process, and the second tantalum layer 2222 and the remaining first tantalum layer 2221 form a second barrier layer.
Illustratively, after step S3, further includes: forming a metal layer on the second barrier layer, wherein the metal layer fills the through hole; planarization (for example, planarization may be performed by a chemical mechanical polishing (chemical mechanical polishing, CMP) process) is performed to remove the first barrier layer, the second barrier layer, and the metal layer in the other region outside the via, where the first barrier layer, the second barrier layer, and the metal layer in the via form the contact hole of the metal interconnect structure. Wherein the metal layer may include a copper seed layer and a metallic copper layer from the outside to the inside, the copper seed layer may be formed on the second barrier layer, and the metallic copper layer (the metallic copper layer may be formed by an electroplating process) may be formed on the copper seed layer to form the metal layer.
In summary, in the embodiment of the present application, after the first barrier layer of the contact hole is formed in the forming process of the metal interconnection structure, the protruding structure formed at the opening of the through hole by the first barrier layer is trimmed by reverse sputtering, so that the opening of the through hole is increased to facilitate the filling of the subsequent metal layer, the generation of filling gaps is reduced to a certain extent, and the reliability and yield of the device are improved.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While nevertheless, obvious variations or modifications may be made to the embodiments described herein without departing from the scope of the invention.
Claims (7)
1. A method of forming a metal interconnect structure, comprising:
forming a first barrier layer on the surfaces of the dielectric layer and the through hole, wherein the through hole is formed in the dielectric layer and is opened on the surface of the dielectric layer;
performing reverse sputtering, and trimming a protrusion structure formed at the opening of the first barrier layer;
and forming a second barrier layer on the surface of the first barrier layer.
2. The method of claim 1, wherein the first barrier layer comprises a tantalum nitride layer.
3. The method of claim 2, wherein forming a first barrier layer on the dielectric layer and the via surface comprises:
and depositing a tantalum nitride layer on the surfaces of the dielectric layer and the through hole through a sputtering process to form the first barrier layer.
4. The method of claim 3, wherein the second barrier layer comprises a tantalum layer.
5. The method of claim 4, wherein forming a second barrier layer on the first barrier layer surface comprises:
depositing a first tantalum layer on the first barrier layer by a sputtering process;
performing reverse sputtering, and trimming the first tantalum layer;
and depositing a second tantalum layer through a sputtering process, wherein the second tantalum layer and the rest of the first tantalum layer form the second barrier layer.
6. The method of any one of claims 1 to 5, wherein after forming a second barrier layer on the surface of the first barrier layer, further comprising:
forming a metal layer on the second barrier layer, wherein the metal layer fills the through hole;
and carrying out planarization treatment, and removing the first barrier layer, the second barrier layer and the metal layer in other areas outside the through hole, wherein the first barrier layer, the second barrier layer and the metal layer in the through hole form a contact hole.
7. The method of claim 6, wherein forming a metal layer on the second barrier layer comprises:
forming a copper seed layer on the second barrier layer;
and forming a metallic copper layer on the copper seed layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310108882.2A CN116031204A (en) | 2023-02-13 | 2023-02-13 | Method for forming metal interconnection structure |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310108882.2A CN116031204A (en) | 2023-02-13 | 2023-02-13 | Method for forming metal interconnection structure |
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| Publication Number | Publication Date |
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| CN116031204A true CN116031204A (en) | 2023-04-28 |
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| CN202310108882.2A Pending CN116031204A (en) | 2023-02-13 | 2023-02-13 | Method for forming metal interconnection structure |
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