Metal wire forming method and semiconductor structure
By depositing a protective layer on the sidewalls of vias, the problem of corrosion of metal wires in porous dielectric layers by volatile small molecules was solved, achieving high-quality metal wires and good current transmission, thus improving the performance of semiconductor structures.
Patent Information
- Application Number
- CN202411179266.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2026-03-06
AI Technical Summary
Metal wires formed in porous dielectric layers are susceptible to corrosion by volatile small molecules, leading to pore defects that affect current transmission capacity and semiconductor structural performance.
A protective layer is formed on the sidewall of the through hole. The protective layer material is a non-metallic material or a metal oxide to prevent volatile small molecules from reacting with the metal wire and avoid corrosion.
This improves the quality of the metal wires, ensures good contact between the metal wires and the metal layer, avoids void defects, enhances current transmission capability, and improves the performance of the semiconductor structure.
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Figure CN121620193A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and in particular to a method for forming a metal wire and a semiconductor structure. Background Technology
[0002] In integrated circuits, copper is often used as a conductor to form metal wires in the dielectric layer, thereby connecting metal layers located at different levels. The common method for preparing metal wires is electrochemical deposition. This method involves etching in the dielectric layer to obtain a via structure that can interconnect with the underlying metal layer, chemically cleaning to remove etching byproducts, and then fabricating metal wires in the via structure.
[0003] However, when the dielectric layer is a porous material, such as porous carbon, like Black Diamond (BD) II, volatile small molecules (e.g., those containing F, Cl, H) from the cleaning solvent used in chemical cleaning can easily remain in the pores of the porous dielectric layer. These volatile small molecules are slowly released and can damage the copper seed layer during subsequent processes, thus affecting the subsequent electrochemical deposition of copper and causing severe cuvoid defects at the edges of the copper metal conductors. (Reference) Figure 1 As shown, this is a schematic diagram of forming a metal wire in the related art. In (a), the porous first dielectric layer 101 is located above the second dielectric layer 102. The second dielectric layer 102 has a metal layer 103. The porous first dielectric layer 101 has a large number of micropores. There are two through holes 104 in the dielectric layer 101. In (b), a large hole 201 appears on the sidewall of the metal wire 105 formed in the through hole 104, which affects the quality of the metal wire. Summary of the Invention
[0004] In view of this, the purpose of this application is to provide a method for forming a metal wire and a semiconductor structure, which avoids damage to the sidewalls of the metal wire to prevent the formation of void defects, improves the quality of the metal wire, and thus ensures the current transmission capability of the metal wire and improves the performance of the semiconductor structure. The specific solution is as follows:
[0005] This application provides a method for forming a metallic wire, comprising:
[0006] A semiconductor structure is provided; the semiconductor structure includes a stacked second dielectric layer and a first dielectric layer, the first dielectric layer comprising a porous material, the second dielectric layer having a metal layer, the first dielectric layer having a plurality of through-holes, and the surface of the metal layer being exposed to the bottom of the through-holes;
[0007] A protective layer is formed at least on the sidewall of the through hole; the material of the protective layer includes non-metallic materials or metal oxides;
[0008] The through-hole is filled with metal material to form a metal wire; the metal wire is connected to the metal layer.
[0009] Optionally, when the material of the protective layer includes the non-metallic material, a protective layer is formed at least on the sidewall of the through hole, including:
[0010] The non-metallic material is deposited within the through-hole;
[0011] The non-metallic material is etched using a plasma etching method to remove the non-metallic material located at the bottom of the through hole, while retaining the non-metallic material located on the sidewall of the through hole.
[0012] Optionally, the non-metallic material includes at least one of polycrystalline silicon, perovskite, and first-generation black diamond materials.
[0013] Optionally, when the material of the protective layer includes the metal oxide, a protective layer is formed at least on the sidewalls of the through-hole, comprising:
[0014] The metal oxide is deposited on the inner wall of the through-hole; the metal wire is connected to the metal layer through the metal oxide.
[0015] Optionally, the metal oxide includes at least one or more combinations of aluminum oxide, copper oxide, titanium oxide, hafnium oxide, zirconium oxide, and tantalum oxide.
[0016] Optionally, the thickness of the protective layer is greater than or equal to 10 angstroms and less than or equal to 100 angstroms.
[0017] Optionally, the protective layer is prepared by chemical vapor deposition, physical vapor deposition, or atomic layer deposition.
[0018] Optionally, the through-hole is filled with a metallic material to form a metallic wire, comprising:
[0019] A barrier layer is formed, which covers the inner wall of the through hole;
[0020] A metal material layer is formed, which covers the surface of the first dielectric layer and fills the via.
[0021] The metal material layer located above the first dielectric layer is planarized to obtain the metal wire.
[0022] This application also provides a semiconductor structure, including:
[0023] A second dielectric layer and a first dielectric layer are stacked; the first dielectric layer comprises a porous material, the second dielectric layer has a metal layer, the first dielectric layer has a plurality of through-holes, and the surface of the metal layer is exposed at the bottom of the through-holes;
[0024] A metal wire is located within the through hole and is connected to the metal layer;
[0025] A protective layer is provided, at least between the sidewall of the through hole and the metal wire, and the material of the protective layer includes non-metallic materials or metal oxides.
[0026] Optionally, the protective layer is also located between the bottom of the through hole and the metal wire.
[0027] This application provides a method for forming a metal wire and a semiconductor structure, which can provide a semiconductor structure. The semiconductor structure includes a stacked second dielectric layer and a first dielectric layer. The first dielectric layer includes a porous material, and the second dielectric layer has a metal layer. The first dielectric layer has multiple vias, and the surface of the metal layer is exposed at the bottom of the vias. A protective layer is formed at least on the sidewalls of the vias. The material of the protective layer includes a non-metallic material or a metal oxide. The vias are filled with metal material to form a metal wire. The metal wire is connected to the metal layer. In this application, by depositing a protective layer on the sidewalls of the vias, regardless of whether the protective layer is a non-metallic material or a metal oxide, it will not react with the volatile small molecules remaining in the first dielectric layer of the porous material, thus preventing damage to the protective layer. This also prevents the metal wire surrounded by the protective layer from being corroded. Therefore, it can ensure good contact between the metal wire and the metal layer, and also prevent damage to the sidewalls of the metal wire to form voids and defects, thereby improving the quality of the metal wire, ensuring the current transmission capability of the metal wire, and improving the performance of the semiconductor structure. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 A schematic diagram of forming a metal wire in a related technology is shown;
[0030] Figure 2 A schematic flowchart of a method for forming a metal wire according to an embodiment of this application is shown;
[0031] Figure 3-9A schematic diagram of a semiconductor structure provided in an embodiment of this application is shown. Detailed Implementation
[0032] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.
[0033] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.
[0034] Secondly, this application provides a detailed description in conjunction with schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.
[0035] As described in the background section, volatile small molecules in the cleaning solvent used for chemical cleaning can easily remain in the pores of the porous first dielectric layer. These volatile small molecules will be slowly released and will damage the copper seed layer during subsequent processes, thereby affecting the subsequent electrochemical deposition of copper and causing severe porosity defects at the edges of the copper metal wires.
[0036] Based on the above technical problems, this application provides a method for forming a metal wire and a semiconductor structure. By depositing a protective layer on the sidewall of the via, regardless of whether the protective layer is a non-metallic material or a metal oxide, it will not react with the volatile small molecules remaining in the first dielectric layer of the porous material, thus preventing damage to the protective layer. This also avoids corrosion of the metal wire surrounded by the protective layer, thereby ensuring good contact between the metal wire and the metal layer and preventing damage to the sidewall of the metal wire to form hole defects. This improves the quality of the metal wire, thereby ensuring the current transmission capability of the metal wire and improving the performance of the semiconductor structure.
[0037] For ease of understanding, the following detailed description, in conjunction with the accompanying drawings, illustrates a method for forming a metal wire and a semiconductor structure provided in the embodiments of this application.
[0038] refer to Figure 2 The diagram shown is a flowchart illustrating a method for forming a metal wire according to an embodiment of this application. The method includes the following steps.
[0039] S101 provides a semiconductor structure including a stacked second dielectric layer and a first dielectric layer, the first dielectric layer including a porous material, the second dielectric layer having a metal layer, the first dielectric layer having a plurality of through holes, and the surface of the metal layer being exposed at the bottom of the through holes.
[0040] In this embodiment, the semiconductor structure may include a stacked second dielectric layer 102 and a first dielectric layer 101. The relative positional relationship between the second dielectric layer 102 and the first dielectric layer 101 is not specifically limited. The second dielectric layer 102 may be located below or above the first dielectric layer 101. This application uses the example of the second dielectric layer 102 being located below the first dielectric layer 101 for illustration. The first dielectric layer 101 and the second dielectric layer 102 may be made of the same material or different materials; for example, both layers may be porous materials.
[0041] The first dielectric layer 101 comprises a porous material, and pores 107 exist within the first dielectric layer 101. For example, the first dielectric layer 101 can be a porous carbon material. After etching the first dielectric layer 101 to obtain multiple vias 104 using plasma etching, chemical cleaning is required to remove etching residues. The chemical solvents used generally include fluorides, amines, and some highly polar organic solvents. Volatile small molecules in these solvents can easily enter and remain in the pores 107. During the subsequent process of forming the metal wire 105, these volatile small molecules will be slowly released, damaging the metal wire 105.
[0042] Metal layers 103 may be present at different locations within the second dielectric layer 102, with one side surface of the metal layer 103 exposed. The metal layer 103 contains numerous metal wirings, which can form a mesh structure, etc. Multiple through-holes 104 may be present through the first dielectric layer 101, with one side surface of the metal layer 103 exposed at the bottom of the through-holes 104. The through-holes 104 are primarily used to interconnect the metal wirings in different dielectric layers. (Reference) Figure 3 The diagram shown is a schematic representation of a semiconductor structure provided in an embodiment of this application. A first dielectric layer 101 is located above a second dielectric layer 102. Two vias 104 are present in the first dielectric layer 101, each exposing a metal layer 103 beneath it. Furthermore, the first dielectric layer 101 contains a large number of pores 107.
[0043] S102, at least on the sidewall of the through hole, a protective layer is formed.
[0044] In the embodiments of this application, reference is made to Figure 4As shown, a protective layer 106 can be formed at least on the sidewall of the through-hole 104. The protective layer 106 can prevent the escape of small molecules remaining in the pore 107. The material of the protective layer 106 can include non-metallic materials or metal oxides. In related technologies, damage to the metal wire 105 is caused by small molecules reacting chemically with the metal wire 105, corroding it, and forming holes on the sidewall of the metal wire 105. By using a different material for the protective layer 106, small molecules will not react with non-metallic materials or metal oxides, thus avoiding damage to the protective layer 106.
[0045] In one possible implementation, the thickness of the protective layer 106 can be greater than or equal to 10 angstroms and less than or equal to 100 angstroms. This can prevent small molecules from escaping and corroding the metal wire 105 if the protective layer 106 is too thin, and also prevent the protective layer 106 from being too thick and affecting the current transmission capability of the metal wire 105.
[0046] In one possible implementation, the protective layer 106 can be prepared by chemical vapor deposition, physical vapor deposition or atomic layer deposition, which can produce a denser protective layer 106.
[0047] S103, fill the through hole with metal material to form a metal wire.
[0048] In this embodiment, a metal wire 105 can be formed by filling the through-hole 104 with metal material. This can be prepared using electrochemical deposition. The metal material can be, for example, copper. The metal wire 105 can connect to the underlying metal layer 103 to ensure current transmission. The metal wire 105 can serve as an interconnect layer, connecting the metal layers 103 located above and below it. The metal material can contact the protective layer 106; since the protective layer 106 is essentially undamaged, the metal material will also not be damaged. (Reference) Figure 4 As shown, a protective layer 106 and a metal wire 105 are present inside the through hole 104.
[0049] In this application, by depositing a protective layer 106 on the sidewall of the via 104, regardless of whether the protective layer 106 is a non-metallic material or a metal oxide, it will not react with the volatile small molecules remaining in the first dielectric layer 101 of the porous material, thus preventing damage to the protective layer 106. This also prevents the metal wire 105 surrounded by the protective layer 106 from being corroded. This ensures good contact between the metal wire 105 and the metal layer 103, and also prevents damage to the sidewall of the metal wire 105 from forming voids and defects, improving the quality of the metal wire 105, thereby ensuring the current transmission capability of the metal wire 105 and improving the performance of the semiconductor structure.
[0050] In one possible implementation, when the material of the protective layer 106 includes a non-metallic material, the protective layer 106 is formed at least on the sidewall of the via 104. Specifically, a non-metallic material is deposited in the via 104, and the non-metallic material is etched using a plasma etching method to remove the non-metallic material located at the bottom of the via 104, while retaining the non-metallic material located on the sidewall of the via 104.
[0051] Specifically, when depositing non-metallic material within the through-hole 104 using methods such as atomic layer deposition, the sidewalls and bottom wall of the through-hole 104 are deposited simultaneously. (Refer to...) Figure 5 As shown, when the protective layer 106 is made of non-metallic material, the non-metallic material located on the bottom wall will affect the electrical connection between the subsequent metal wire 105 and the metal layer 103. Therefore, it is necessary to remove the non-metallic material on the bottom wall in a timely manner.
[0052] Specifically, plasma etching can be used to remove the non-metallic material on the bottom wall of the via 104, leaving only the non-metallic material on the sidewalls of the via 104. The gas used during etching can include gases containing C and F, as well as O2 and Ar. It is understood that the etching parameters are not specifically limited during the removal process, but the etching rate in the vertical direction must be greater than the etching rate in the horizontal direction. This ensures that while the non-metallic material on the bottom wall is removed, a certain thickness of non-metallic material remains on the sidewalls of the via 104.
[0053] In this way, when the protective layer 106 is a non-metallic material, timely removal of the protective layer 106 located at the bottom of the through hole 104 can not only ensure that the protective layer 106 on the side wall of the through hole 104 can protect the metal wire 105 and prevent it from having holes, but also ensure the electrical connection effect between the metal wire 105 and the metal layer 103, and ensure the current transmission capability.
[0054] In one possible implementation, the non-metallic material may include at least one of polycrystalline silicon, perovskite, and first-generation black diamond material, wherein the pores 107 in the first-generation black diamond material are very small and can be basically ignored, which can block the diffusion of small molecules in the first dielectric layer 101 of the second-generation black diamond material without reacting with them. In summary, polycrystalline silicon, perovskite, and first-generation black diamond materials can provide good protection for the metal wire 105.
[0055] In one possible implementation, filling the through hole 104 with metal material to form the metal wire 105 can specifically involve forming a barrier layer 108, which covers the inner wall of the through hole 104, forming a metal material layer 109, which covers the surface of the first dielectric 101 and fills the through hole; and planarizing the metal material layer 109 located above the first dielectric layer 101 to obtain the metal wire 105.
[0056] In other words, a barrier layer 108 can be formed after the protective layer 106 is formed by methods such as sputtering deposition, as shown in the reference. Figure 6 As shown, the barrier layer 108 can be made of TAN / TA, followed by the deposition of a metal material to form the metal wire 105. Furthermore, a copper seed layer may be present between the barrier layer 108 and the metal wire 105. Figure 6 The copper seed layer is not shown. During the formation of the metal wire 105, not only is metal material deposited within the via 104, but a metal material layer 109 is also deposited on the surface of the first dielectric layer 101. (See reference...) Figure 7 As shown, the metal material layer 109 on the surface of the first dielectric layer 101 needs to be removed. This can be achieved by chemical mechanical polishing to planarize it, leaving only the metal material layer 109 within the through-hole 104, thus obtaining the metal wire 105. (Refer to...) Figure 8 As shown.
[0057] In one possible implementation, when the material of the protective layer 106 includes a metal oxide, the protective layer 106 is formed at least on the sidewall of the through hole 104. Specifically, a metal oxide is deposited on the inner wall of the through hole 104, and the metal wire 105 is connected to the metal layer 103 through the metal oxide.
[0058] Specifically, when a protective layer 106 is deposited inside the through-hole 104, it covers the sidewalls and bottom wall of the through-hole 104. When the protective layer 106 is a metal oxide, the metal oxide has a certain conductivity, so the metal wire 105 can be connected to the metal through the metal oxide to realize current transmission. Therefore, it is not necessary to remove the protective layer 106 located on the bottom wall of the through-hole 104, which can reduce the process flow and shorten the process time. Reference Figure 9 As shown, the protective layer 106 covers the sidewalls and bottom wall of the through hole 104.
[0059] In one possible implementation, the metal oxide may include at least one or more combinations of aluminum oxide, copper oxide, titanium oxide, hafnium oxide, zirconium oxide, and tantalum oxide, which can both protect the metal wire 105 and provide a good electrical connection between the metal wire 105 and the metal layer 103.
[0060] Furthermore, before forming the protective layer 106 of the metal oxide material, a barrier layer 108 and a copper seed layer can be deposited in the via 104. Additionally, a planarization process can be performed to remove excess metal material, resulting in a metal wire 105 resting on the surface of the first dielectric layer 101. Figure 9 As shown.
[0061] This application provides a method for forming a metal wire, which can provide a semiconductor structure. The semiconductor structure includes a stacked second dielectric layer and a first dielectric layer. The first dielectric layer includes a porous material, and the second dielectric layer has a metal layer. The first dielectric layer has multiple vias, and the surface of the metal layer is exposed at the bottom of the vias. A protective layer is formed at least on the sidewalls of the vias. The material of the protective layer includes a non-metallic material or a metal oxide. The vias are filled with the metal material to form a metal wire. The metal wire is connected to the metal layer. In this application, by depositing a protective layer on the sidewalls of the vias, regardless of whether the protective layer is a non-metallic material or a metal oxide, it will not react with the volatile small molecules remaining in the first dielectric layer of the porous material, thus preventing damage to the protective layer. This also prevents the metal wire surrounded by the protective layer from being corroded. Therefore, it can ensure good contact between the metal wire and the metal layer, and also prevent damage to the sidewalls of the metal wire to form voids and defects, improving the quality of the metal wire, thereby ensuring the current transmission capability of the metal wire and improving the performance of the semiconductor structure.
[0062] Based on the method for forming a metal wire provided in the above embodiments, this application also provides a semiconductor structure, see reference. Figure 4 As shown. The semiconductor structure includes:
[0063] A second dielectric layer 102 and a first dielectric layer 101 are stacked; the first dielectric layer 101 includes a porous material, the second dielectric layer 102 has a metal layer 103, the first dielectric layer 101 has a plurality of through holes 104, and the surface of the metal layer 103 is exposed to the bottom of the through holes 104.
[0064] Metal wire 105 is located inside through hole 104 and is connected to metal layer 103;
[0065] A protective layer 106 is located at least between the sidewall of the through hole 104 and the metal wire 105. The material of the protective layer 106 includes non-metallic materials or metal oxides.
[0066] Optionally, the protective layer 106 is also located between the bottom of the through hole 104 and the metal wire 105.
[0067] Optionally, the non-metallic material includes at least one of polycrystalline silicon, perovskite, and first-generation black diamond materials.
[0068] Optionally, the metal oxide includes at least one or more combinations of aluminum oxide, copper oxide, titanium oxide, hafnium oxide, zirconium oxide, and tantalum oxide.
[0069] Optionally, the thickness of the protective layer is greater than or equal to 10 angstroms and less than or equal to 100 angstroms.
[0070] This application provides a semiconductor structure including a stacked second dielectric layer and a first dielectric layer. The first dielectric layer includes a porous material, and the second dielectric layer has a metal layer. The first dielectric layer has multiple vias, and the surface of the metal layer is exposed at the bottom of the vias. A metal wire is located within the via. The metal wire is connected to the metal layer. A protective layer is located between the sidewall of the via and the metal wire. The protective layer is made of a non-metallic material or a metal oxide. In this application, by depositing a protective layer on the sidewall of the via, regardless of whether the protective layer is a non-metallic material or a metal oxide, it will not react with the volatile small molecules remaining in the porous first dielectric layer, thus preventing damage to the protective layer. This also prevents corrosion of the metal wire surrounded by the protective layer, ensuring good contact between the metal wire and the metal layer while preventing damage to the sidewall of the metal wire to form voids. This improves the quality of the metal wire, thereby ensuring its current transmission capability and improving the performance of the semiconductor structure.
[0071] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, structural embodiments are generally similar to method embodiments and are therefore described simply; relevant details can be found in the descriptions of the method embodiments.
[0072] The above description is merely a preferred embodiment of this application. Although this application has disclosed preferred embodiments above, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.
Claims
1. A method of forming a metal wire, characterized by, The application provides a semiconductor structure and a method for manufacturing the semiconductor structure. The semiconductor structure comprises a first dielectric layer and a second dielectric layer stacked together, the first dielectric layer comprises porous material, the second dielectric layer comprises a metal layer, the first dielectric layer comprises a plurality of through holes, and a surface of the metal layer is exposed at a bottom of the through holes; A protective layer is formed on at least a sidewall of the through holes; The material of the protective layer comprises non-metallic material or metal oxide; A metal material is filled in the through holes to form a metal wire; The metal wire is connected with the metal layer.
2. The method of claim 1, wherein, When the material of the protective layer comprises the non-metallic material, the method for forming the protective layer on at least the sidewall of the through holes comprises: The non-metallic material is deposited in the through holes; The non-metallic material is etched by a plasma etching method to remove the non-metallic material at the bottom of the through holes and retain the non-metallic material on the sidewall of the through holes.
3. The method of claim 2, wherein, The non-metallic material comprises at least one of polysilicon, perovskite and black diamond generation material.
4. The method of claim 1, wherein, When the material of the protective layer comprises the metal oxide, the method for forming the protective layer on at least the sidewall of the through holes comprises: The metal oxide is deposited on an inner wall of the through holes; and the metal wire is connected with the metal layer through the metal oxide.
5. The method of claim 4, wherein, The metal oxide comprises at least one of aluminum oxide, copper oxide, titanium oxide, hafnium oxide, zirconium oxide and tantalum oxide or a combination of multiple thereof.
6. The method of claim 1, wherein, The thickness of the protective layer is greater than or equal to 10 angstroms and less than or equal to 100 angstroms.
7. The method of claim 1, wherein, The protective layer is prepared by a chemical vapor deposition method, a physical vapor deposition method or an atomic layer deposition method.
8. The method of claim 1, wherein, The method for filling the metal material in the through holes to form the metal wire comprises: A barrier layer is formed to cover the inner wall of the through holes; A metal material layer is formed to cover a surface of the first dielectric layer and fill the through holes; The metal material layer above the first dielectric layer is planarized to obtain the metal wire.
9. A semiconductor structure, characterized by The semiconductor structure comprises a first dielectric layer and a second dielectric layer stacked together, the first dielectric layer comprises porous material, the second dielectric layer comprises a metal layer, the first dielectric layer comprises a plurality of through holes, and a surface of the metal layer is exposed at a bottom of the through holes; A metal wire is located in the through holes and connected with the metal layer; A protective layer is located between at least a sidewall of the through holes and the metal wire, and the material of the protective layer comprises non-metallic material or metal oxide. The protective layer is also located between the bottom of the through holes and the metal wire.
10. The semiconductor structure of claim 9, wherein,