An interconnect structure and method of making the same
By introducing a structure consisting of a first barrier layer, an interface layer, and a second barrier layer into the contact hole, the problem of insufficient barrier layer blocking capability is solved, thereby increasing the volume of the conductive layer and reducing the resistance-capacitance delay.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN CHUXING TECH CO LTD
- Filing Date
- 2024-11-26
- Publication Date
- 2026-06-02
AI Technical Summary
The barrier layer in the existing contact hole fabrication process has poor blocking ability, which leads to the need to increase the thickness of the barrier layer, thereby reducing the volume of the conductive layer filling the contact hole.
A barrier layer structure comprising a first barrier layer, an interface layer, and a second barrier layer is adopted. The interface layer is formed by oxygen plasma treatment, which breaks the grain boundary distribution, improves the barrier capability, and reduces the thickness of the barrier layer to increase the filling volume of the conductive layer.
It improves the blocking ability of the barrier layer, reduces the resistance and capacitance delay, increases the filling volume of the conductive layer, and saves material costs.
Smart Images
Figure CN122138690A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor technology, and in particular to an interconnect structure and its fabrication method. Background Technology
[0002] In the manufacturing process of integrated circuits (ICs), the fabrication of contact holes is a crucial step, used to connect different conductive layers and ensure the normal operation of the circuit. Current contact hole fabrication processes have relatively poor barrier layer capabilities, requiring increased barrier layer thickness, which in turn reduces the volume of the conductive layer filling the contact hole. Summary of the Invention
[0003] This invention discloses an interconnect structure and its fabrication method, which is used to increase the volume of the conductive layer filled in the contact hole by reducing the thickness of the barrier layer by improving the barrier layer's blocking ability.
[0004] To achieve the above objectives, the present invention provides the following technical solution:
[0005] In a first aspect, the present invention provides an interconnection structure, comprising:
[0006] Substrate;
[0007] A dielectric layer is located on one side of the substrate;
[0008] Contact holes penetrate the dielectric layer;
[0009] An adhesive layer that at least covers the sidewalls of the contact hole and the portion of the substrate exposed by the contact hole;
[0010] A barrier layer is located on the side of the adhesive layer opposite to the substrate; the barrier layer includes a first barrier layer, an interface layer, and a second barrier layer; the interface layer is located between the first barrier layer and the second barrier layer.
[0011] A conductive layer is located on the side of the barrier layer opposite to the adhesive layer and fills the contact hole.
[0012] The aforementioned interconnect structure includes contact holes that penetrate the dielectric layer. These contact holes are covered by an adhesive layer and a barrier layer, and filled with a conductive layer. The barrier layer comprises a first barrier layer, a second barrier layer, and an interface layer located between the first and second barrier layers. This interface layer breaks down the grain boundary distribution between the first and second barrier layers, creating a clear boundary between them. This prevents fluoride ions from diffusing along the grain boundary fast channels, thus improving the barrier layer's blocking capability. Furthermore, the thickness of the barrier layer can be reduced, increasing the filling volume of the conductive layer within the contact hole and decreasing the resistance-capacitance (RC) delay.
[0013] In some embodiments, the thickness of the barrier layer along the depth direction of the contact hole ranges from [specific value].
[0014] In some embodiments, the thickness of the interface layer along the depth direction of the contact hole is [missing information].
[0015] In some embodiments, the thickness of the first barrier layer and / or the second barrier layer along the depth direction of the contact hole is [missing information].
[0016] Secondly, the present invention also provides a method for preparing an interconnect structure, comprising:
[0017] Deposit a dielectric layer on the substrate;
[0018] The dielectric layer is patterned to form contact holes that penetrate the dielectric layer.
[0019] An adhesive layer is formed on the sidewall of the contact hole and on the portion of the substrate exposed by the contact hole;
[0020] A barrier layer is formed on the side of the adhesive layer opposite to the substrate;
[0021] A conductive layer is formed on the side of the barrier layer opposite to the adhesive layer, and the conductive layer fills the contact hole;
[0022] Wherein, a barrier layer is formed on the side of the adhesive layer opposite to the substrate, including:
[0023] A first barrier layer is formed on the side of the adhesive layer opposite to the substrate;
[0024] The side of the first barrier layer away from the adhesive layer is treated with oxygen plasma to form a first barrier layer and an interface layer.
[0025] A second barrier layer is formed on the side of the interface layer opposite to the first barrier layer.
[0026] In some embodiments, the oxygen plasma treatment of the side of the first barrier layer opposite to the adhesive layer to form the first barrier layer and the interface layer includes:
[0027] The first barrier layer is subjected to oxygen plasma treatment for 5-10 seconds on the side of the first barrier layer away from the adhesive layer to form the interface layer; wherein the first barrier layer is the portion of the first barrier layer excluding the interface layer.
[0028] In some embodiments, an adhesive layer is formed on the sidewalls of the contact hole and on the portion of the substrate exposed by the contact hole, including:
[0029] An adhesive layer is formed by depositing metal on the sidewalls of the contact hole and on the portion of the substrate exposed by the contact hole;
[0030] And / or, a barrier layer is formed on the side of the adhesive layer opposite to the substrate, comprising:
[0031] A metal nitride film is deposited on the side of the adhesive layer away from the substrate, and the metal nitride film is subjected to plasma treatment to form a first barrier layer;
[0032] The side of the first barrier layer away from the adhesive layer is treated with oxygen plasma to form a first barrier layer and an interface layer.
[0033] A metal nitride film is deposited on the side of the interface layer opposite to the first barrier layer, and the metal nitride film is subjected to plasma treatment to form a second barrier layer;
[0034] And / or, a conductive layer is formed on the side of the barrier layer opposite to the adhesive layer, the conductive layer filling the contact hole; including:
[0035] Metal is deposited on the side of the barrier layer opposite to the adhesive layer and the contact holes are filled to form a conductive layer.
[0036] In some embodiments, the thickness of the barrier layer ranges from
[0037] In some embodiments, the thickness of the interface layer is
[0038] In some embodiments, the thickness of the first barrier layer and / or the second barrier layer is Attached Figure Description
[0039] Figure 1 This is a schematic diagram of an interconnection structure provided in an embodiment of the present invention;
[0040] Figure 2 A flowchart illustrating a method for fabricating an interconnect structure according to an embodiment of the present invention;
[0041] Figure 3 Here is the flowchart for S204;
[0042] Figure 4 A flowchart illustrating the determination process of an interconnect structure fabrication method provided in this embodiment of the invention;
[0043] Figures 5-10 A process flow diagram for fabricating an interconnect structure provided in an embodiment of the present invention;
[0044] Icons: 1-Substrate; 2-Dielectric layer; 3-Contact hole; 4-Adhesive layer; 5-Barrier layer; 6-Conductive layer; 51-First barrier layer; 52-Interface layer; 53-Second barrier layer. Detailed Implementation
[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in the text is only a description of the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can mean: A alone, A and B at the same time, and B alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.
[0046] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.
[0047] Firstly, such as Figure 1 As shown, an embodiment of the present invention provides an interconnection structure, including:
[0048] Substrate 1;
[0049] Dielectric layer 2 is located on one side of substrate 1;
[0050] Contact hole 3 penetrates dielectric layer 2;
[0051] The adhesive layer 4 covers at least the sidewalls of the contact hole 3 and the portion of the substrate 1 exposed by the contact hole 3;
[0052] The barrier layer 5 is located on the side of the adhesive layer 4 away from the substrate 1; the barrier layer 5 includes a first barrier layer 51, an interface layer 52 and a second barrier layer 53; the interface layer 52 is located between the first barrier layer 51 and the second barrier layer 53.
[0053] The conductive layer 6 is located on the side of the barrier layer 5 away from the adhesive layer 4 and fills the contact hole 3.
[0054] The interconnect structure described above includes a contact hole 3 penetrating the dielectric layer 2. The contact hole 3 is covered by an adhesive layer 4 and a barrier layer 5, and filled with a conductive layer 6. The barrier layer 5 comprises a first barrier layer 51, a second barrier layer 53, and an interface layer 52 located between the first and second barrier layers 51 and 53. This layer breaks the grain boundary distribution between the first and second barrier layers 51 and 53, creating a clear boundary between them. This prevents fluoride ions from diffusing along the grain boundary fast channels, improving the barrier layer 5's blocking capability. Furthermore, the thickness of the barrier layer 5 can be reduced, increasing the filling volume of the conductive layer 6 within the contact hole 3 and decreasing the resistance-capacitance (RC) delay.
[0055] In some embodiments, the dielectric layer 2 is a silicon dioxide layer, i.e., SiO2; the adhesive layer 4 is a titanium metal layer, i.e., Ti; the first barrier layer 51 is a titanium nitride film, i.e., TiN; the interface layer 52 is an oxygen-containing titanium nitride film, i.e., TiN(O); and the second barrier layer 53 is a titanium nitride film, i.e., TiN.
[0056] In some embodiments, the thickness of the barrier layer 5 along the depth direction of the contact hole 3 ranges from [specific value missing]. like or In the interconnect structure provided by the embodiments of the present invention, the barrier layer 5 has a strong blocking ability and the thickness of the barrier layer 5 can be reduced. For example, the thickness of the barrier layer 5 is reduced by 20%.
[0057] In some embodiments, the thickness of the interface layer 52 along the depth direction of the contact hole 3 is [missing information]. like or Interface layer 52 can improve the ability of barrier layer 5 to block the erosion of fluoride ions in subsequent processes.
[0058] In some embodiments, the thickness of the first barrier layer 51 and / or the second barrier layer 53 along the depth direction of the contact hole 3 is [missing information].
[0059] In some embodiments, the thickness of the first barrier layer 51 along the depth direction of the contact hole 3 is [missing information]. like or
[0060] Secondly, such as Figure 2 As shown, this embodiment of the invention also provides a method for fabricating an interconnect structure, comprising the following steps:
[0061] S201, Deposit a dielectric layer on the substrate;
[0062] S202. Pattern the dielectric layer to form contact holes, which penetrate the dielectric layer.
[0063] S203. An adhesive layer is formed on the sidewall of the contact hole and on the portion of the substrate exposed by the contact hole;
[0064] S204. A barrier layer is formed on the side of the adhesive layer away from the substrate.
[0065] S205. A conductive layer is formed on the side of the barrier layer away from the adhesive layer, and the conductive layer fills the contact hole.
[0066] Specifically, the following describes step S204 in the fabrication method of the above interconnect structure:
[0067] like Figure 3 As shown, a barrier layer is formed on the side of the adhesive layer away from the substrate, including the following steps:
[0068] S301. A first barrier layer is formed on the side of the adhesive layer away from the substrate.
[0069] S302. The side of the first barrier layer away from the adhesive layer is treated with oxygen plasma to form the first barrier layer and the interface layer.
[0070] S303. A second barrier layer is formed on the side of the interface layer away from the first barrier layer.
[0071] In some embodiments, in S302 above, oxygen plasma treatment is performed on the side of the first barrier layer away from the adhesive layer to form a first barrier layer and an interface layer, including:
[0072] The first barrier layer is subjected to oxygen plasma treatment for 5-10 seconds on the side facing away from the adhesive layer to form an interface layer; wherein the first barrier layer is the part of the first barrier layer excluding the interface layer.
[0073] Oxygen plasma treatment of titanium nitride (TiN) films can form an oxygen-containing titanium nitride film, typically denoted as TiN(O). This treatment method introduces oxygen plasma, causing some nitrogen atoms in the titanium nitride to be replaced by oxygen atoms or forming an oxide layer on the film surface. The chemical composition of this film is between that of pure TiN and TiO2, with the specific ratio depending on the oxygen plasma treatment conditions (such as treatment time, power, gas flow rate, etc.). Oxygen plasma treatment causes changes in the lattice structure of the film, forming an amorphous or mixed-phase structure, i.e., the interface layer in this embodiment. The interface layer can prevent fluoride ions from diffusing along the fast channels of grain boundaries, improving the barrier layer's blocking ability.
[0074] In some embodiments, an adhesive layer is formed on the sidewalls of the contact hole and on the portion of the substrate exposed by the contact hole, including:
[0075] An adhesive layer is formed by depositing metal on the sidewalls of the contact hole and on the portion of the substrate exposed by the contact hole; the metal is titanium (Ti);
[0076] And / or, a barrier layer is formed on the side of the adhesive layer opposite to the substrate, including:
[0077] A metal nitride film is deposited on the side of the adhesive layer away from the substrate, and the metal nitride film is subjected to plasma treatment to form a first barrier layer; the metal nitride is titanium nitride (TiN); the first barrier layer is a first dense titanium nitride film.
[0078] The side of the first barrier layer away from the adhesive layer is treated with oxygen plasma to form the first barrier layer and the interface layer; the first barrier layer is still a dense titanium nitride film, and the interface layer is a TiN(O) film.
[0079] A metal nitride film is deposited on the side of the interface layer away from the first barrier layer, and the metal nitride film is subjected to plasma treatment to form a second barrier layer; the metal nitride is titanium nitride (TiN);
[0080] And / or, a conductive layer is formed on the side of the barrier layer opposite to the adhesive layer, the conductive layer filling the contact hole; including:
[0081] A conductive layer is formed by depositing metal on the side of the barrier layer away from the adhesive layer and filling the contact holes. The metal is tungsten.
[0082] To make the solutions provided in the embodiments of the present invention easier to understand, the fabrication process of the interconnect structure provided in the embodiments of the present invention will be described in detail below through a specific embodiment. For example... Figure 4 As shown, the process includes the following steps:
[0083] S401, Deposit a dielectric layer on the substrate;
[0084] S402. Pattern the dielectric layer to form contact holes, which penetrate the dielectric layer.
[0085] S403. An adhesive layer is formed on the sidewall of the contact hole and on the portion of the substrate exposed by the contact hole;
[0086] S404. A metal nitride film is deposited on the side of the adhesive layer away from the substrate, and the metal nitride film is subjected to plasma treatment to form a first barrier layer.
[0087] S405. The side of the first barrier layer away from the adhesive layer is treated with oxygen plasma to form the first barrier layer and the interface layer.
[0088] S406. A metal nitride film is deposited on the side of the interface layer away from the first barrier layer, and the metal nitride film is subjected to plasma treatment to form a second barrier layer.
[0089] S407. Deposit metal on the side of the barrier layer away from the adhesive layer and fill the contact holes to form a conductive layer.
[0090] It should be noted that the deposition methods used in the embodiments of the present invention are all chemical vapor deposition (CVD). For example, plasma-enhanced CVD (PECVD) is used in the interconnect structure fabrication process, which utilizes plasma to enhance chemical reactions and can be deposited at a lower temperature.
[0091] In some embodiments, the plasma treatment in the first barrier layer fabrication process uses both hydrogen and nitrogen gas simultaneously. The plasma treatment in the interface layer fabrication process uses oxygen gas. The plasma treatment in the second barrier layer fabrication process uses both hydrogen and nitrogen gas simultaneously.
[0092] like Figure 5 As shown, a dielectric layer 2 is deposited on substrate 1; the material of dielectric layer 2 is silicon dioxide. Figure 6 As shown, the dielectric layer 2 is patterned to form contact holes 3, which penetrate the dielectric layer 2. Figure 7 As shown, a titanium metal adhesive layer 4 is deposited on the sidewalls of the contact hole 3 and on the portion of the substrate 1 exposed by the contact hole 3 to form an adhesive layer. Figure 8 As shown, a titanium nitride thin film is deposited on the side of the adhesive layer 4 away from the substrate 1. This film has a high impurity content and a porous texture. The titanium nitride thin film is subjected to plasma treatment with both hydrogen and oxygen to remove carbon (C) and hydrogen (H) impurities, making the film denser to form the first barrier layer 5. Figure 9 As shown, the first barrier layer 5, on the side facing away from the adhesive layer 4, is subjected to oxygen plasma treatment for 5-10 seconds, forming on the surface of the first barrier layer 5. The TiN(O) interface layer 52 is used to improve the barrier layer 5's ability to block fluorine (F) ions from subsequent processes, forming a first barrier layer 51 and an interface layer 52. Figure 10 As shown, a titanium nitride thin film is deposited on the side of the interface layer 52 opposite to the first barrier layer 51. This film has a high impurity content and a porous texture. The titanium nitride thin film is subjected to plasma treatment with both hydrogen and oxygen to remove carbon (C) and hydrogen (H) impurities, making the film denser and significantly reducing the overall resistivity, thus forming the second barrier layer 53. Figure 1As shown, tungsten metal is deposited on the side of the second barrier layer 53 away from the interface layer 52 and the contact hole 3 is filled to form a conductive layer 6, thus completing the fabrication of the interconnect structure.
[0093] The interconnect structure provided in this embodiment of the invention performs a secondary plasma treatment after the deposition of the first metal nitride film to form a TiN(O) interface layer 52 on the surface of the first film. This breaks the grain boundary distribution between the two films, prevents fluoride ions from diffusing along the grain boundary fast channel, and improves its blocking ability. This reduces the thickness of the entire blocking layer 5, increases the filling volume of the conductive metal in the contact hole 3, reduces RC, and saves 30% of the power.
[0094] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.
Claims
1. An interconnection structure, characterized in that, include: Substrate; A dielectric layer is located on one side of the substrate; Contact holes penetrate the dielectric layer; An adhesive layer that at least covers the sidewalls of the contact hole and the portion of the substrate exposed by the contact hole; A barrier layer is located on the side of the adhesive layer opposite to the substrate; the barrier layer includes a first barrier layer, an interface layer, and a second barrier layer; the interface layer is located between the first barrier layer and the second barrier layer. A conductive layer is located on the side of the barrier layer opposite to the adhesive layer and fills the contact hole.
2. The interconnection structure according to claim 1, characterized in that, Along the depth direction of the contact hole, the thickness of the barrier layer ranges from [value missing].
3. The interconnection structure according to claim 1, characterized in that, Along the depth direction of the contact hole, the thickness of the interface layer is 4. The interconnection structure according to claim 1, characterized in that, Along the depth direction of the contact hole, the thickness of the first barrier layer and / or the second barrier layer is 5. A method for fabricating an interconnect structure, characterized in that, include: Deposit a dielectric layer on the substrate; The dielectric layer is patterned to form contact holes that penetrate the dielectric layer. An adhesive layer is formed on the sidewall of the contact hole and on the portion of the substrate exposed by the contact hole; A barrier layer is formed on the side of the adhesive layer opposite to the substrate; A conductive layer is formed on the side of the barrier layer opposite to the adhesive layer, and the conductive layer fills the contact hole; Wherein, a barrier layer is formed on the side of the adhesive layer opposite to the substrate, including: A first barrier layer is formed on the side of the adhesive layer opposite to the substrate; The side of the first barrier layer away from the adhesive layer is treated with oxygen plasma to form a first barrier layer and an interface layer. A second barrier layer is formed on the side of the interface layer opposite to the first barrier layer.
6. The method according to claim 5, characterized in that, The step of treating the side of the first barrier layer away from the adhesive layer with oxygen plasma to form the first barrier layer and the interface layer includes: The first barrier layer is subjected to oxygen plasma treatment for 5-10 seconds on the side of the first barrier layer away from the adhesive layer to form the interface layer; wherein the first barrier layer is the portion of the first barrier layer excluding the interface layer.
7. The method according to claim 5, characterized in that, An adhesive layer is formed on the sidewall of the contact hole and on the portion of the substrate exposed by the contact hole, comprising: An adhesive layer is formed by depositing metal on the sidewalls of the contact hole and on the portion of the substrate exposed by the contact hole; And / or, a barrier layer is formed on the side of the adhesive layer opposite to the substrate, comprising: A metal nitride film is deposited on the side of the adhesive layer away from the substrate, and the metal nitride film is subjected to plasma treatment to form a first barrier layer; The side of the first barrier layer away from the adhesive layer is treated with oxygen plasma to form a first barrier layer and an interface layer. A metal nitride film is deposited on the side of the interface layer opposite to the first barrier layer, and the metal nitride film is subjected to plasma treatment to form a second barrier layer; And / or, a conductive layer is formed on the side of the barrier layer opposite to the adhesive layer, the conductive layer filling the contact hole; including: Metal is deposited on the side of the barrier layer opposite to the adhesive layer and the contact holes are filled to form a conductive layer.
8. The method according to claim 5, characterized in that, The thickness range of the barrier layer is:
9. The method according to claim 5, characterized in that, The thickness of the interface layer is 10. The method according to claim 5, characterized in that, The thickness of the first barrier layer and / or the second barrier layer is