Metal wire manufacturing method and semiconductor structure

Abstract

The embodiment of the invention discloses a metal wire manufacturing method and a semiconductor structure. The method comprises the following steps: forming a metal layer of a ruthenium material on a substrate; performing first etching on the metal layer to form a trench intermediate structure; depositing a carbon-based protection layer on the inner wall of the groove middle structure; performing second etching on the carbon-based protection layer at the bottom of the groove middle structure to remove the carbon-based protection layer, and oxidizing the exposed surface of the ruthenium material to form a ruthenium dioxide surface layer; performing third etching on the ruthenium dioxide surface layer to remove and expose the surface of the ruthenium material below so as to perform first etching again; sequentially and repeatedly executing the processes of first etching, carbon-based protection layer deposition, second etching and third etching until a groove completion structure and segmented metal wires are formed; and cleaning the side wall of the groove. According to the embodiment of the invention, the problem of poor roughness of the side wall in the etching process can be solved from the source, the risk of short circuit or open circuit is reduced, and lower resistance and interconnection stability are realized.

Description

Technical Field

[0001] This application relates to the field of semiconductor processing technology, and in particular to a method for manufacturing metal wires and a semiconductor structure. Background Technology

[0002] At advanced nodes, when forming metal interconnect layers on substrates, the industry is exploring subtractive patterning processes (depositing metal first, then etching the pattern) to create the most critical and densely patterned bottom metal layers (such as M1 and M2). Currently, ruthenium (Ru) is one of the best materials for the subtractive patterning method for bottom metal layers. Traditionally, Ru patterning typically uses a single-step etching method, but during etching, the byproduct tends to deposit on the sidewalls, producing residues (RuO). x / RuCl y This unevenness can affect the sidewall roughness of the Ru metal line as it is etched downwards, increasing the risk of short circuits or open circuits due to uneven linewidth. It also affects overlay accuracy and degrades the connection quality with the upper metal vias. Furthermore, these problems hinder the fabrication of high aspect ratio Ru metal lines, making it difficult to reduce resistance. Therefore, it is necessary to investigate a process method that can significantly improve these issues. Summary of the Invention

[0003] The purpose of this application is to overcome the aforementioned problems in the prior art and to provide a method for manufacturing metal wires and a semiconductor structure.

[0004] To achieve the above objectives, the technical solution of this application is as follows: According to a first aspect of this application, embodiments of this application provide a method for manufacturing a metal wire, comprising: Provide substrate; A metal layer is formed on the surface of the substrate, and the metal layer material is ruthenium; The surface of the metal layer is first etched using oxygen-containing gas and chlorine-containing gas to form a trench intermediate structure on the metal layer. A carbon-based protective layer is deposited on the inner wall of the intermediate structure of the trench using a hydrocarbon-containing gas. Using oxygen-containing gas, the carbon-based protective layer on the bottom of the trench intermediate structure is etched a second time to remove it, and the surface of the ruthenium material exposed on the bottom is oxidized to form a ruthenium dioxide surface layer. The ruthenium dioxide surface layer formed on the bottom is removed by a third etching using oxygen-containing gas and chlorine-containing gas to expose the surface of the underlying ruthenium material for the first etching to be performed again. The first etching, deposition of the carbon-based protective layer, the second etching, and the third etching are repeated sequentially until a through trench completion structure evolved from the trench intermediate structure is formed on the metal layer, so as to form multiple metal lines divided by the trench completion structure on the surface of the substrate. Additionally, hydrogen-containing gas is used for cleaning the trench sidewalls.

[0005] In some embodiments, the cleaning of the trench sidewalls using hydrogen-containing gas specifically includes: using hydrogen-containing gas to perform a first cleaning on the sidewalls of the completed trench structure to remove the carbon-based protective layer and the oxide layer present on the sidewalls.

[0006] In some embodiments, the use of hydrogen-containing gas to clean the trench sidewalls specifically includes: after each preset number of third etching operations, using hydrogen-containing gas to perform a second cleaning on the sidewalls of the intermediate structure of the trench, in order to reduce any residual products.

[0007] In some embodiments, during the third etching, a chlorine-containing gas is added to the oxygen-containing gas to react with the ruthenium dioxide surface layer to generate volatile RuO. x Cl y A complex is used to remove the ruthenium dioxide surface layer.

[0008] In some embodiments, during the first etching, the ratio of chlorine gas flow rate to oxygen gas flow rate is 1:10 to 3:10, the total flow rate of oxygen gas and chlorine gas is 50 sccm to 300 sccm, the temperature is 20°C to 60°C, the pressure is 5 mTorr to 50 mTorr, the source power is 300 W to 800 W, the bias power is 10 W to 100 W, and the time is 0.1 s to 15 s.

[0009] In some embodiments, when depositing the carbon-based protective layer, a first diluent gas is also added to the hydrocarbon-containing gas. The flow rate of the hydrocarbon-containing gas to the first diluent gas is 1:4 to 1:6, the total flow rate of the hydrocarbon-containing gas and the first diluent gas is 50 sccm to 300 sccm, the temperature is 20°C to 60°C, the pressure is 10 mTorr to 100 mTorr, the source power is 100 W to 500 W, the bias power is 0 W to 20 W, and the time is 0.1 s to 5 s.

[0010] In some embodiments, during the second etching, the oxygen-containing gas flow rate is 30 sccm to 200 sccm, the temperature is 20°C to 60°C, the pressure is 5 mTorr to 50 mTorr, the source power is 200 W to 600 W, the bias power is 10 W to 60 W, and the time is 0.1 s to 5 s.

[0011] In some embodiments, during the third etching, the ratio of chlorine gas flow rate to oxygen gas flow rate is 1:10 to 3:10, the total flow rate of oxygen gas and chlorine gas is 20 sccm to 200 sccm, the temperature is 20°C to 60°C, the pressure is 5 mTorr to 50 mTorr, the source power is 300 W to 800 W, the bias power is 50 W to 120 W, and the time is 0.1 s to 8 s.

[0012] In some embodiments, during the first cleaning, a second diluent gas is also added to the hydrogen-containing gas, with a hydrogen-containing gas flow rate to second diluent gas flow rate ratio of 1:4 to 1:6. The total flow rate of the hydrogen-containing gas and the second diluent gas is 200 sccm to 1000 sccm, the temperature is 20°C to 60°C, the pressure is 50 mTorr to 500 mTorr, the source power is 200 W to 600 W, the bias power is 10 W to 30 W, and the time is 5 s to 15 s.

[0013] In some embodiments, during the second cleaning, a third diluent gas is added to the hydrogen-containing gas, with a hydrogen-containing gas flow rate to third diluent gas flow rate ratio of 1:4 to 1:6. The total flow rate of the hydrogen-containing gas and the third diluent gas is 100 sccm to 300 sccm, the temperature is 20°C to 60°C, the pressure is 20 mTorr to 100 mTorr, the source power is 100 W to 500 W, the bias power is 0 W, and the time is 0.1 s to 5 s.

[0014] In some embodiments, the oxygen-containing gas includes O2 or O3.

[0015] In some embodiments, the chlorine-containing gas includes Cl2.

[0016] In some embodiments, the hydrocarbon-containing gas includes at least one of CH4, C2H4, and C3H6.

[0017] In some embodiments, the hydrogen-containing gas includes H2.

[0018] In some embodiments, the preset number of times is 5 to 10 times.

[0019] According to a second aspect of this application, embodiments of this application also provide a semiconductor structure obtained using a metal wire manufacturing method as provided in any of the embodiments of the first aspect above.

[0020] The embodiments of this application may have, or at least have, the following advantages: (1) By forming a carbon-based protective layer on the inner wall of the trench structure during the etching process of the ruthenium metal layer, the sidewall can be isolated and protected. On the one hand, it can prevent the sidewall from contacting the etching gas, avoid damage to the formed etching morphology, and prevent the upper dimension from continuously increasing with repeated etching, thus ensuring etching uniformity and perpendicularity. On the other hand, it can effectively protect the polycrystalline ruthenium material grain boundaries on the sidewall, avoiding the phenomenon of severe unevenness (grain steps) caused by the different oxidation rates of ruthenium grains with different crystal orientations (grain boundaries are preferentially etched) under long-term oxidation. This can keep the sidewall surface smooth at all times, thereby greatly reducing non-volatile byproducts (RuO2). x / RuCl y This reduces the probability of deposition and residue on the sidewalls, thus maintaining a low roughness on the sidewalls as etching continues, improving linewidth uniformity, significantly reducing the risk of short circuits or open circuits, effectively reducing overlay errors, and ensuring good connection with the upper metal vias.

[0021] (2) By adding chlorine gas to the oxygen-containing gas during the first etching, the probability of generating non-volatile substances (RuO2) can be effectively reduced, thereby promoting the continuous etching of ruthenium. By forming a carbon-based protective layer, the density and strength of the material and its good filling ability can be utilized. Only a very thin thickness is required to resist the bombardment of scattered ions during etching, which can avoid surface roughness caused by sidewall damage. It is also conducive to selective removal (second etching) using etching gas (oxygen-containing gas), and the process compatibility is high. By using oxygen-containing gas for the second etching, while selectively removing the carbon-based protective layer on the bottom, the surface of the ruthenium material exposed on the bottom can be oxidized to form a ruthenium dioxide surface layer. The surface chemical state of the ruthenium material on the bottom can be directionally solidified, thereby facilitating the use of the same flow ratio of oxygen-containing gas and chlorine gas and similar menu conditions as the first etching for the third etching. The reaction with the ruthenium dioxide surface layer generates volatile RuO2. x Cl y The complex is removed, achieving a smooth transition between the first and second etching steps. This ensures the continuous downward progress of anisotropic etching and avoids issues affecting etching uniformity caused by significant menu adjustments. Therefore, by sequentially repeating the first etching, carbon-based protective layer deposition, second etching, and third etching processes, sidewall-protected cyclic anisotropic etching of the ruthenium metal layer can be performed, ensuring etching uniformity and perpendicularity. This allows the etching process to continue downward, enabling the creation of ruthenium metal lines with higher aspect ratios and higher interconnect density, thereby significantly reducing interconnect resistance.

[0022] (3) By performing a first cleaning on the sidewalls of the completed trench structure, carbon-based protective layers can be removed, carbon-containing contaminants on the sidewalls can be removed, and oxide layers (including natural oxide layers or possible residual RuO) present on the sidewalls can be removed. x / RuCl y The reduction to ruthenium provides a clean and active ruthenium metal surface, which can effectively passivate the dangling bonds and highly active sites on the surface and reduce the surface state density, thus providing a more ideal nucleation surface for subsequent film deposition.

[0023] (4) By performing a second cleaning on the sidewalls of the trench structure after each preset number of third etching cycles, any residual products (byproducts) on the sidewalls can be promptly reduced. These byproducts can then be removed in the next etching cycle by forming volatiles (RuO4), thus preventing the formation of a "micromask" due to prolonged residue, which would cause randomly distributed unevenness on the sidewalls during subsequent etching, resulting in poor sidewall roughness. Furthermore, by setting differentiated process conditions (reducing flow rate, pressure, source power, turning off bias power, shortening time, etc.), the effectiveness of the hydrogen plasma can be weakened, achieving both priority reduction of residual products on the sidewalls and maximizing the preservation of the carbon-based protective layer (H atoms and RuO4) on the sidewalls. x The reaction is dominated by chemisorption, and the required energy is lower than the etching threshold of the carbon-based protective layer, ensuring the continuous and stable progress of cyclic etching.

[0024] The embodiments of this application have strong process compatibility and can improve the sidewall roughness problem from the source during the etching process, reduce the risk of short circuit or open circuit, achieve lower resistance and interconnection stability, and well meet the technical requirements of advanced nodes.

[0025] Other advantages of this application will be described in the following detailed description. Attached Figure Description

[0026] Figure 1 This is a flowchart of a metal wire manufacturing method provided in a preferred embodiment of this application.

[0027] Figure 2 This is a schematic diagram of a ruthenium metal layer and a mask formed on a substrate, according to a preferred embodiment of this application.

[0028] Figure 3 This is a schematic diagram of a first trench intermediate structure formed on a ruthenium metal layer, according to a preferred embodiment of this application.

[0029] Figure 4 This is a schematic diagram of a carbon-based protective layer formed on the inner wall of the intermediate structure of the first trench, according to a preferred embodiment of this application.

[0030] Figure 5 This is a schematic diagram of a preferred embodiment of the present application after removing the carbon-based protective layer on the bottom of the intermediate structure of the first trench and forming a ruthenium dioxide surface layer on the bottom.

[0031] Figure 6 This is a schematic diagram of a preferred embodiment of the present application after removing the ruthenium dioxide surface layer.

[0032] Figure 7 This is a schematic diagram of a second trench intermediate structure further formed on a ruthenium metal layer, according to a preferred embodiment of this application.

[0033] Figure 8 This is a schematic diagram of a carbon-based protective layer formed on the inner wall of the intermediate structure of the second trench, according to a preferred embodiment of this application.

[0034] Figure 9 This is a schematic diagram of a trench-completed structure and ruthenium metal wire provided in a preferred embodiment of this application.

[0035] Figure 10 This is a schematic diagram of a preferred embodiment of the present application after removing the residual carbon-based protective layer.

[0036] In the figure: 10. Substrate; 11. Ruthenium metal layer; 111. Ruthenium metal line; 12. Mask; 13. First trench intermediate structure; 14. Carbon-based protective layer; 15. Ruthenium dioxide surface layer; 16. Second trench intermediate structure; 17. Completed trench structure. Detailed Implementation

[0037] To address the problem that traditional single-step etching methods for patterning ruthenium (Ru) result in poor sidewall roughness of the formed Ru metal wires, which can easily lead to short circuits or open circuits, this application provides a metal wire manufacturing method, including: Provide substrate; A metal layer is formed on the surface of the substrate, and the metal layer material is ruthenium; The surface of the metal layer is first etched using oxygen-containing gas and chlorine-containing gas to form a trench intermediate structure on the metal layer. A carbon-based protective layer is deposited on the inner wall of the intermediate structure of the trench using a hydrocarbon-containing gas. Using oxygen-containing gas, the carbon-based protective layer on the bottom of the trench intermediate structure is etched a second time to remove it, and the surface of the ruthenium material exposed on the bottom is oxidized to form a ruthenium dioxide surface layer. The ruthenium dioxide surface layer formed on the bottom is removed by a third etching using oxygen-containing gas and chlorine-containing gas to expose the surface of the underlying ruthenium material for the first etching to be performed again. The first etching, deposition of the carbon-based protective layer, the second etching, and the third etching are repeated sequentially until a through trench completion structure evolved from the trench intermediate structure is formed on the metal layer, so as to form multiple metal lines divided by the trench completion structure on the surface of the substrate. Additionally, hydrogen-containing gas is used for cleaning the trench sidewalls.

[0038] In this embodiment, a carbon-based protective layer is formed on the inner wall of the trench structure during the etching process of the ruthenium metal layer. This isolates and protects the sidewalls, ensuring etching uniformity and perpendicularity, keeping the sidewall surface smooth at all times, and significantly reducing non-volatile byproducts (RuO₂). x / RuCl y This reduces the chance of deposition and residue on the sidewalls, thus maintaining a low roughness on the sidewalls as etching continues, improving linewidth uniformity, significantly reducing the risk of short circuits or open circuits, greatly reducing overlay errors, and ensuring good connection with the upper metal vias.

[0039] This application also provides a semiconductor structure obtained using the metal wire manufacturing method described above.

[0040] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0041] refer to Figure 1 In a first aspect, embodiments of this application provide a method for manufacturing a metal wire, which may sequentially include the following steps: Step S11: Provide a substrate.

[0042] refer to Figure 2 In some embodiments, a substrate 10 is used for further forming ruthenium metal lines on the substrate 10 to form the semiconductor structure provided in the embodiments of this application. The substrate 10 may include any suitable type of semiconductor substrate and material. For example, the substrate 10 may include a silicon (Si) substrate, a germanium (Ge) substrate, or a germanium-silicon (SiGe) substrate, or a III / V compound semiconductor substrate, such as a gallium arsenide (GaAs) substrate, an indium gallium arsenide (InGaAs) substrate, or similar materials.

[0043] In some embodiments, substrate 10 may include a wafer.

[0044] Step S12: Form a ruthenium metal layer on the surface of the substrate.

[0045] refer to Figure 2 In some embodiments, a deposition process may be used to form a ruthenium metal layer, namely a ruthenium metal layer 11, on the surface of the substrate 10.

[0046] Step S13: Perform the first etching on the surface of the metal layer to form a trench intermediate structure on the metal layer.

[0047] refer to Figure 2 In some embodiments, a plurality of masks 12 are formed on the surface of the ruthenium metal layer 11, and any two adjacent masks 12 have an opening that serves as an etching window.

[0048] In some embodiments, the material of the mask 12 may be a medium, such as silicon dioxide.

[0049] refer to Figure 3 In some embodiments, plasma containing oxygen gas and chlorine gas can be used, and an anisotropic first etching (main etching) is performed on the surface of the exposed ruthenium metal layer 11 through the etching window between the masks 12, forming a first trench intermediate structure 13 (trench intermediate structure) on the surface of the ruthenium metal layer 11 at the bottom of the opening.

[0050] In some embodiments, the oxygen-containing gas may include O2 or O3 (the same applies below).

[0051] In some embodiments, the chlorine-containing gas may include Cl2 (the same applies below).

[0052] In some embodiments, the first etching is performed using a mixture of oxygen-containing gas (O2) and chlorine-containing gas (Cl2) (chlorine is added to the oxygen), and the flow rate ratio between the flow rate of the chlorine-containing gas and the flow rate of the oxygen-containing gas is 0.1 to 0.3 (chlorine-containing gas flow rate: oxygen-containing gas flow rate = 1:10 to 3:10). For example, the flow rate ratio of chlorine-containing gas to oxygen-containing gas can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.3, or any value between any two of the aforementioned flow rate ratios. Adding a certain proportion of chlorine to oxygen can promote the formation of volatile RuO4 and avoid (reduce) the formation of non-volatile RuO2 (which has poor volatility and only decomposes and partially vaporizes above 1400℃; its residue on the sidewalls can lead to poor sidewall roughness). Specifically, adding chlorine to the etching gas can generate volatile RuCl. x O y The complex helps break down any existing dense RuO2 layer, promoting the continued etching of Ru (RuCl). x O y Its volatility is lower than that of RuO4.

[0053] In some embodiments, during the first etching, the total flow rate of the oxygen-containing gas and the chlorine-containing gas is 50 sccm to 300 sccm. For example, the total flow rate of the oxygen-containing gas and the chlorine-containing gas may be 50 sccm, 60 sccm, 80 sccm, 100 sccm, 110 sccm, 150 sccm, 180 sccm, 200 sccm, 220 sccm, 250 sccm, 270 sccm, 290 sccm, or 300 sccm, or any value between any two of the aforementioned flow rate values.

[0054] In some embodiments, the temperature during the first etching is between 20°C and 60°C. For example, the temperature can be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, or any value between any two of the aforementioned temperature values. Within the aforementioned temperature range, the conversion of the generated RuO4 to RuO2 can be avoided.

[0055] In some embodiments, the pressure during the first etching is 5 mTorr to 50 mTorr. For example, the pressure may be 5 mTorr, 10 mTorr, 15 mTorr, 20 mTorr, 25 mTorr, 30 mTorr, 35 mTorr, 40 mTorr, 45 mTorr, or 50 mTorr, or any value between any two of the aforementioned pressure values.

[0056] In some embodiments, the source power is 300W to 800W during the first etching. For example, the source power may be 300W, 350W, 400W, 450W, 500W, 550W, 600W, 650W, 700W, 750W or 800W, or any value between any two of the aforementioned power values.

[0057] In some embodiments, the bias power during the first etching is 10W to 100W. For example, the bias power can be 10W, 20W, 30W, 40W, 50W, 60W, 70W, 80W, 90W, or 100W, or any value between any two of the aforementioned power values. Periodic pulse etching can be formed by setting the bias power to alternately turn on and off, with a duty cycle of 10% to 30%, to reduce the damage to the sidewalls caused by etching and optimize the anisotropy of the etching. It can also further optimize the removal of reaction products, reduce the occurrence of lateral etching, and contribute to the reduction of sidewall roughness.

[0058] In some embodiments, the time for the first etching is between 0.1 s and 15 s. For example, the time can be 0.1 s, 0.2 s, 0.3 s, 0.5 s, 0.8 s, 1 s, 1.5 s, 1.7 s, 2 s, 3 s, 5 s, 10 s, 13 s, or 15 s, or any value between any two of the aforementioned time values. The etching time can be adjusted according to the size of the critical dimension.

[0059] Thus, through the coordinated control of the above-mentioned flow ratio, flow rate, temperature, pressure, source power, bias power, time, etc., anisotropic first etching is achieved on the surface of the ruthenium metal layer 11 in the opening, forming a first trench intermediate structure 13 with uniform size and good morphology of a certain depth on the surface of the ruthenium metal layer 11 at the bottom of the opening.

[0060] Step S14: Deposit a carbon-based protective layer on the inner wall of the intermediate structure of the trench.

[0061] refer to Figure 4 In some embodiments, a plasma containing hydrocarbon gas can be used to treat the inner wall of the first trench intermediate structure 13, depositing a carbon-based protective layer 14 on the inner wall of the first trench intermediate structure 13 to isolate and protect the sidewalls.

[0062] In some embodiments, the hydrocarbon-containing gas includes at least one of CH4, C2H4, and C3H6. A first diluent gas may be added to the hydrocarbon-containing gas. The first diluent gas may be an inert gas, such as helium (He).

[0063] Taking CH4 as an example of a hydrocarbon-containing gas, when CH4 is dissociated in plasma, it generates a series of active groups (such as CH3, CH2, and CH radicals), which are the main precursors for forming the carbon-based protective layer 14. The hydrocarbon radicals and ions in the CH4 plasma can form a nanoscale-thick layer of C-containing compounds or a layer containing C and CH through adsorption, injection, and cross-linking reactions on the inner wall of the first trench intermediate structure 13. x Compound layers (e.g., amorphous hydrocarbon films (aC:H)). Their main functions may include: (a) utilizing their excellent filling ability to fill and cover grain boundaries, suppressing preferential grain boundary etching, keeping sidewall surfaces smooth, and thus greatly reducing non-volatile byproducts (RuO₂). x / RuCl y(a) Reduces the probability of deposition and residue on the sidewalls. (b) When performing a second etching with oxygen-containing gas, it facilitates the removal of the bottom carbon-based protective layer 14 while retaining the carbon-based protective layer 14 on the sidewalls, achieving selective protection and high process compatibility. (c) Utilizing the density and robustness of its material, only an extremely thin thickness is required to resist the bombardment of scattered ions during etching, avoiding surface roughness caused by sidewall damage. (d) Blocks the sidewalls from contacting the etching gas, preventing damage to the formed etching morphology and preventing the upper dimension from continuously increasing with repeated etching, ensuring etching uniformity and perpendicularity.

[0064] In some embodiments, when depositing the carbon-based protective layer 14, the flow rate ratio between the introduced hydrocarbon gas and the first diluent gas is: hydrocarbon gas flow rate : first diluent gas flow rate = 1:4 to 1:6. For example, the flow rate ratio of hydrocarbon gas to first diluent gas can be 1:4, 1:4.1, 1:4.5, 1:4.8, 1:5, 1:5.1, 1:5.5, 1:5.9, or 1:6, etc., and the flow rate ratio of the first diluent gas can continuously vary between 4 and 6.

[0065] In some embodiments, when depositing the carbon-based protective layer 14, the total flow rate of the hydrocarbon-containing gas and the first dilution gas is 50 sccm to 300 sccm. For example, the total flow rate can be 50 sccm, 60 sccm, 80 sccm, 100 sccm, 110 sccm, 120 sccm, 150 sccm, 180 sccm, 200 sccm, 210 sccm, 240 sccm, 290 sccm, or 300 sccm, or any value between any two of the aforementioned flow rate values.

[0066] In some embodiments, the temperature during deposition of the carbon-based protective layer 14 is 20°C to 60°C. For example, the temperature may be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, or any value between any two of the aforementioned temperature values.

[0067] In some embodiments, the pressure during deposition of the carbon-based protective layer 14 is 10 mTorr to 100 mTorr. For example, the pressure may be 10 mTorr, 20 mTorr, 30 mTorr, 40 mTorr, 50 mTorr, 60 mTorr, 70 mTorr, 80 mTorr, 90 mTorr, or 100 mTorr, or any value between any two of the aforementioned pressure values.

[0068] In some embodiments, when depositing the carbon-based protective layer 14, the source power is 100W to 500W. For example, the source power can be 100W, 150W, 200W, 250W, 300W, 350W, 400W, 450W or 500W, or any value between any two of the aforementioned power values.

[0069] In some embodiments, when depositing the carbon-based protective layer 14, the bias power is 0W to 20W. For example, the bias power can be 0W, 1W, 2W, 5W, 8W, 10W, 12W, 15W, 18W, or 20W, or any value between any two of the aforementioned power values. When the bias power is greater than 0W, periodic pulse deposition can be formed by setting the bias power to alternately turn on and off; or, the bias power can be set to be continuously turned on, with the goal of forming a uniform carbon-based protective layer 14 on the sidewall.

[0070] In some embodiments, the time for depositing the carbon-based protective layer 14 is 0.1s to 5s. For example, the time can be 0.1s, 0.2s, 0.3s, 0.5s, 0.8s, 1s, 1.5s, 1.7s, 2s, 3s, 4s or 5s, or any value between any two of the aforementioned time values.

[0071] Thus, through the coordinated regulation of the above-mentioned flow ratio, flow rate, temperature, pressure, source power, bias power, time, etc., a carbon-based protective layer 14 with uniform film thickness is formed on the sidewall, thereby achieving effective protection of the sidewall.

[0072] Step S15: Perform a second etching to remove the carbon-based protective layer on the bottom of the trench's intermediate structure, and oxidize the exposed ruthenium material surface to form a ruthenium dioxide surface layer.

[0073] refer to Figure 5 In some embodiments, an oxygen-containing gas (e.g., O2) can be used to perform a second etching on the carbon-based protective layer 14 at the bottom of the first trench intermediate structure 13. Utilizing the resulting anisotropic etching effect and controlling the process conditions, the carbon-based protective layer 14 at the bottom is selectively removed, exposing the surface of the ruthenium material at the bottom while retaining the carbon-based protective layer 14 on the sidewalls for continuous protection. In this step, oxygen without added chlorine is used as the etching gas. The purpose is to rapidly perform shallow oxidation on the surface of the exposed ruthenium material at the bottom after selectively removing the carbon-based protective layer 14, forming a ruthenium dioxide surface layer 15 (non-volatile) on the surface of the ruthenium material at the bottom. The "self-limiting stagnation" effect of ruthenium dioxide (the oxidation to RuO4 reaction stops once a dense RuO2 layer is formed) prevents further oxidation, avoiding damage to the bottom morphology. This prevents subsequent etching from causing sidewall angle tilting or abrupt dimensional changes due to poor bottom morphology.

[0074] In some embodiments, the oxygen-containing gas flow rate during the second etching is 30 sccm to 200 sccm. For example, the oxygen-containing gas flow rate can be 30 sccm, 40 sccm, 50 sccm, 60 sccm, 80 sccm, 100 sccm, 110 sccm, 130 sccm, 150 sccm, 170 sccm, 190 sccm, or 200 sccm, or any value between any two of the aforementioned flow rate values.

[0075] In some embodiments, the temperature during the second etching is 20°C to 60°C. For example, the temperature may be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, or any value between any two of the aforementioned temperature values.

[0076] In some embodiments, the pressure during the second etching is 5 mTorr to 50 mTorr. For example, the pressure may be 5 mTorr, 10 mTorr, 15 mTorr, 20 mTorr, 25 mTorr, 30 mTorr, 35 mTorr, 40 mTorr, 45 mTorr, or 50 mTorr, or any value between any two of the aforementioned pressure values.

[0077] In some embodiments, the source power is 200W to 600W during the second etching. For example, the source power may be 200W, 210W, 230W, 250W, 270W, 290W, 300W, 350W, 400W, 450W, 500W, 550W, or 600W, or any value between any two of the aforementioned power values.

[0078] In some embodiments, during the second etching, the bias power is 10W to 60W. For example, the bias power can be 10W, 15W, 20W, 25W, 30W, 35W, 40W, 45W, 50W, 55W, or 60W, or any value between any two of the aforementioned power values. The bias power can be set to remain continuously on to increase the etching energy in a non-pulsed manner to reduce the etching time.

[0079] In some embodiments, the second etching time is 0.1s to 5s, sufficient to effectively generate ruthenium dioxide. For example, the time can be 0.1s, 0.2s, 0.3s, 0.5s, 0.7s, 0.9s, 1s, 1.1s, 1.5s, 1.8s, 2s, 2.5s, 3s, 3.5s, 4s, 4.5s, or 5s, or any value between any two of the aforementioned time values.

[0080] Thus, through the coordinated control of the above-mentioned flow rate, temperature, pressure, source power, bias power, time, etc., the carbon-based protective layer 14 on the bottom can be selectively removed, forming a ruthenium dioxide surface layer 15 on the exposed ruthenium material, and the carbon-based protective layer 14 on the sidewall can be effectively retained to provide continuous protection for the sidewall.

[0081] Step S16: Perform a third etching on the ruthenium dioxide surface to remove it, exposing the surface of the underlying ruthenium material, so as to perform a first etching again.

[0082] refer to Figure 6 In some embodiments, an oxygen-containing gas and a chlorine-containing gas can be used to perform a third etching on the ruthenium dioxide surface layer 15 formed on the bottom of the first trench intermediate structure 13 to remove the ruthenium dioxide surface layer 15, exposing the fresh surface of the ruthenium material beneath the ruthenium dioxide surface layer 15 for subsequent first etching. In this step, chlorine gas is added to the oxygen as an etching gas to perform the third etching on the ruthenium dioxide surface layer 15 formed on the bottom. When a certain proportion of chlorine gas is added to the oxygen, it can react with the ruthenium dioxide material of the ruthenium dioxide surface layer 15 to generate volatile RuO. x Cl y The complex (x=2~4, y=0~2) can remove the ruthenium dioxide surface layer 15.

[0083] In some embodiments, during the third etching, the flow rate ratio between the chlorine-containing gas and the oxygen-containing gas is 0.1 to 0.3 (chlorine-containing gas flow rate: oxygen-containing gas flow rate = 1:10 to 3:10). For example, the flow rate ratio of chlorine-containing gas to oxygen-containing gas can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.3, or any value between any two of the aforementioned flow rate ratios.

[0084] In some embodiments, during the third etching, the total flow rate of the oxygen-containing gas and the chlorine-containing gas is 20 sccm to 200 sccm. For example, the flow rate of the oxygen-containing gas can be 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 80 sccm, 100 sccm, 110 sccm, 130 sccm, 150 sccm, 170 sccm, 190 sccm, or 200 sccm, or any value between any two of the aforementioned flow rate values.

[0085] In some embodiments, the temperature during the third etching is 20°C to 60°C. For example, the temperature may be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, or any value between any two of the aforementioned temperature values.

[0086] In some embodiments, the pressure during the third etching is 5 mTorr to 50 mTorr. For example, the pressure can be 5 mTorr, 10 mTorr, 15 mTorr, 20 mTorr, 25 mTorr, 30 mTorr, 35 mTorr, 40 mTorr, 45 mTorr, or 50 mTorr, or any value between any two of the aforementioned pressure values.

[0087] In some embodiments, the source power is 300W to 800W during the third etching. For example, the source power may be 300W, 350W, 400W, 450W, 500W, 550W, 600W, 650W, 700W, 750W or 800W, or any value between any two of the aforementioned power values.

[0088] In some embodiments, during the third etching, the bias power is 50W to 120W. For example, the bias power can be 50W, 55W, 60W, 65W, 70W, 75W, 80W, 85W, 90W, 95W, 100W, 105W, 110W, 115W, or 120W, or any value between any two of the aforementioned power values. The bias power can be set to remain continuously on to increase the etching energy in a non-pulsed manner to quickly remove the ruthenium dioxide surface layer 15.

[0089] In some embodiments, the time for the third etching is 0.1s to 8s. For example, the time can be 0.1s, 0.2s, 0.5s, 0.9s, 1s, 1.2s, 1.5s, 2s, 2.5s, 3s, 3.5s, 4s, 4.5s, 5s, 5.5s, 6s, 6.5s, 7s, 7.5s, or 8s, or any value between any two of the aforementioned time values.

[0090] By coordinating and controlling the above-mentioned flow ratio, flow rate, temperature, pressure, source power, bias power, time, etc., the ruthenium dioxide surface layer 15 can be quickly removed, so as to quickly switch to the first etching step of a new round and achieve continuous anisotropic etching.

[0091] In summary, by using oxygen-containing gas for the second etching, the carbon-based protective layer 14 on the bottom is selectively removed. Simultaneously, the surface of the exposed ruthenium material on the bottom is oxidized to form a ruthenium dioxide surface layer 15. This directional solidification of the surface chemical state of the ruthenium material on the bottom facilitates the use of the same flow rate ratio of oxygen-containing gas and chlorine-containing gas, and similar menu conditions as the first etching. The ruthenium dioxide surface layer 15 reacts with the ruthenium dioxide to generate volatile RuO. x Cl y The removal of the complex allows for a smooth transition between the first and second etching processes, ensuring the continuous downward progress of anisotropic etching and avoiding issues that could affect etching uniformity due to significant menu adjustments.

[0092] Step S17: After completing the third etching operation for each preset number of times, clean the sidewalls of the structure in the middle of the trench.

[0093] refer to Figure 7 In some embodiments, by performing the above step S13 to perform the first etching again, that is, to continue etching downwards on the bottom of the first trench intermediate structure 13, a deeper second trench intermediate structure 16 is formed on the basis of the first trench intermediate structure 13 (the second trench intermediate structure 16, as a trench intermediate structure, includes the first trench intermediate structure 13).

[0094] Then, by performing the above step S14, a carbon-based protective layer 14 is deposited on the inner wall of the intermediate structure 16 of the second trench, such as... Figure 8 As shown. By continuing to execute step S15, the carbon-based protective layer 14 on the bottom of the second trench intermediate structure 16 is selectively removed, and the exposed ruthenium material surface is oxidized to form a ruthenium dioxide surface layer. By continuing to execute step S16 to remove the ruthenium dioxide surface layer, a deeper third trench intermediate structure (not shown) is formed on the basis of the second trench intermediate structure 16 by executing step S13 again. This cycle continues to form deeper fourth trench intermediate structures, fifth trench intermediate structures, etc., up to the Nth trench intermediate structure (for example, N=10 to 100, but is not limited to this).

[0095] In this process, after each preset number of third etching operations (i.e., after each cycle of executing steps S13 to S16 a preset number of times), hydrogen-containing gas is used to clean the trench sidewalls (second cleaning). This second cleaning of the sidewalls of the formed trench intermediate structure removes residual products (RuO₂) from the sidewalls. x / RuCl y To restore.

[0096] In some embodiments, the hydrogen-containing gas includes H2.

[0097] In some embodiments, the preset number of times is 5 to 10. For example, the first second cleaning can be performed after the formation of the fifth, sixth, seventh, eighth, ninth, or tenth trench intermediate structures. Then, at the same or different intervals (preset number of times), a second second cleaning is performed on the newly formed trench intermediate structures after another preset number of times, and so on.

[0098] The second cleaning removes the residual products (RuO2) from the sidewalls. x / RuCl y It is reduced to ruthenium and can be removed by the formation of volatiles (RuO4) during the first etching of the next cycle. This prevents the formation of a "micromask" due to long-term residue of the product, which would cause randomly distributed unevenness on the sidewalls during subsequent etching and result in poor sidewall roughness.

[0099] Furthermore, by setting differentiated process conditions (reducing flow rate, lowering pressure, reducing source power, shutting off bias power, shortening time, etc. (relative to the first cleaning)), the effectiveness of the hydrogen plasma can be weakened, thereby achieving both preferential reduction of residual products on the sidewalls and maximizing the retention of the carbon-based protective layer 14 (H atoms and RuO) on the sidewalls. x / RuCl y The reaction is dominated by chemisorption, and the required energy is lower than the etching threshold of the carbon-based protective layer 14, thus ensuring the continuous and stable progress of cyclic etching.

[0100] In some embodiments, during the second cleaning, a third diluent gas (e.g., helium) is added to the hydrogen-containing gas (e.g., H2). The flow rate ratio between the introduced hydrogen-containing gas and the third diluent gas is: hydrogen-containing gas flow rate : third diluent gas flow rate = 1:4 to 1:6. For example, the flow rate ratio can be 1:4, 1:4.1, 1:4.2, 1:4.5, 1:4.9, 1:5, 1:5.1, 1:5.5, 1:5.8, or 1:6, etc., and the flow rate ratio of the third diluent gas can be continuously varied between 4 and 6.

[0101] In some embodiments, during the second cleaning, the total flow rate of the hydrogen-containing gas and the third dilution gas is 100 sccm to 300 sccm. For example, the total flow rate of the hydrogen-containing gas and the third dilution gas may be 100 sccm, 110 sccm, 120 sccm, 150 sccm, 180 sccm, 200 sccm, 220 sccm, 240 sccm, 270 sccm, 290 sccm, or 300 sccm, or any value between any two of the aforementioned flow rate values.

[0102] In some embodiments, the temperature during the second cleaning is 20°C to 60°C. For example, the temperature may be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, or any value between any two of the aforementioned temperature values.

[0103] In some embodiments, the pressure during the second cleaning is 20 mTorr to 100 mTorr. For example, the pressure may be 20 mTorr, 30 mTorr, 40 mTorr, 50 mTorr, 60 mTorr, 70 mTorr, 80 mTorr, 90 mTorr, or 100 mTorr, or any value between any two of the aforementioned pressure values.

[0104] In some embodiments, the source power is 100W to 500W during the second cleaning. For example, the source power may be 100W, 150W, 200W, 250W, 300W, 350W, 400W, 450W or 500W, or any value between any two of the aforementioned power values.

[0105] In some embodiments, the bias power is 0W during the second cleaning. By turning off the bias power, the bombardment of plasma is eliminated, sputtering is reduced, and damage to the carbon-based protective layer 14 on the sidewall is avoided.

[0106] In some embodiments, the second cleaning is performed for a period of 0.1s to 5s. For example, the time can be 0.1s, 0.2s, 0.3s, 0.5s, 0.8s, 1s, 1.5s, 1.7s, 2s, 3s, 4s or 5s, or any value between any two of the aforementioned time values.

[0107] Thus, through the coordinated control of the above-mentioned flow ratio, flow rate, temperature, pressure, source power, bias power, time, etc., the processing efficiency of hydrogen plasma can be made "weak" to the point that it is not enough to significantly etch the carbon-based protective layer 14. At the same time, the reaction to reduce the residual products can still occur. Therefore, while reducing the products remaining on the sidewall surface, the carbon-based protective layer 14 on the sidewall can be preserved to the maximum extent.

[0108] Step S18: Repeat steps S13 to S17 until the trench is formed to complete the structure and metal wire.

[0109] In some embodiments, by repeatedly performing steps S13 to S17, namely, repeatedly performing the first etching to form a new trench intermediate structure, depositing a carbon-based protective layer on the inner wall of the new trench intermediate structure, performing a second etching to remove the carbon-based protective layer on the bottom of the new trench intermediate structure and oxidizing the exposed ruthenium material surface to form a ruthenium dioxide surface layer, performing a third etching to remove the ruthenium dioxide surface layer, exposing the surface of the underlying ruthenium material for another first etching, and performing a second cleaning on the sidewalls of the newly formed trench intermediate structure after each preset number of cycles. This cycle is repeated until the bottom of the newly formed trench intermediate structure stops on the surface of the substrate 10, and a trench completion structure 17 extending through the thickness direction of the ruthenium metal layer 11 is formed on the ruthenium metal layer 11, which is evolved from the updated trench intermediate structure formed in each cycle. This results in a plurality of ruthenium metal lines 111 divided by the trench completion structure 17 on the surface of the substrate 10, such as... Figure 9 As shown.

[0110] By sequentially repeating the processes of first etching, deposition of a carbon-based protective layer, second etching, and third etching, and after each preset number of third etching cycles, the middle structure of the trench is cleaned to achieve sidewall-protected cyclic anisotropic etching of the ruthenium metal layer 11. This avoids residues on the sidewalls, improves sidewall smoothness, and ensures etching uniformity and perpendicularity, thus improving the process from the source. This allows the etching process to proceed steadily downwards, thereby enabling the creation of ruthenium metal lines 111 with higher aspect ratios and higher interconnect density, and significantly reducing interconnect resistance.

[0111] Step S19: Clean the sidewalls of the completed trench structure.

[0112] refer to Figure 10 In some embodiments, a hydrogen-containing gas (e.g., H2) may be used to clean the sidewalls of the trench completion structure 17 (first cleaning) to remove the carbon-based protective layer and the oxide layer present on the sidewalls.

[0113] By performing a first cleaning on the sidewalls of the trench-completed structure 17, carbon-containing contaminants on the sidewalls can be removed simultaneously with the removal of the carbon-based protective layer. This also removes the oxide layer (including the native oxide layer or any residual RuO) present on the sidewalls of the ruthenium metal wire 111. x / RuCl y The reduction to ruthenium provides a clean and active ruthenium metal surface, which can effectively passivate the dangling bonds and highly active sites on the surface and reduce the surface state density, thus providing a more ideal nucleation surface for subsequent film deposition.

[0114] The mask 12 on top of the ruthenium metal wire 111 can be retained after the first cleaning (subsequent film layers are generally made of low dielectric constant materials).

[0115] In some embodiments, during the first cleaning, a second diluent gas (e.g., helium) is added to the hydrogen-containing gas (e.g., H2). The flow rate ratio between the introduced hydrogen-containing gas and the second diluent gas is: hydrogen-containing gas flow rate : second diluent gas flow rate = 1:4 to 1:6. For example, the flow rate ratio can be 1:4, 1:4.1, 1:4.2, 1:4.5, 1:4.9, 1:5, 1:5.1, 1:5.5, 1:5.8, or 1:6, etc., and the flow rate ratio of the second diluent gas can be continuously varied between 4 and 6.

[0116] In some embodiments, during the first cleaning, the total flow rate of the hydrogen-containing gas and the second dilution gas is 200 sccm to 1000 sccm. For example, the total flow rate of the hydrogen-containing gas and the second dilution gas can be 200 sccm, 300 sccm, 400 sccm, 500 sccm, 600 sccm, 700 sccm, 800 sccm, 900 sccm, or 1000 sccm, or any value between any two of the aforementioned flow rate values.

[0117] In some embodiments, the temperature during the first cleaning is 20°C to 60°C. For example, the temperature may be 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C, or any value between any two of the aforementioned temperature values.

[0118] In some embodiments, the pressure during the first cleaning is 50 mTorr to 500 mTorr. For example, the pressure may be 50 mTorr, 60 mTorr, 80 mTorr, 100 mTorr, 150 mTorr, 200 mTorr, 250 mTorr, 300 mTorr, 350 mTorr, 400 mTorr, 450 mTorr, or 500 mTorr, or any value between any two of the aforementioned pressure values.

[0119] In some embodiments, the source power is 200W to 600W during the first cleaning. For example, the source power may be 200W, 250W, 300W, 350W, 400W, 450W, 500W, 550W, or 600W, or any value between any two of the aforementioned power values.

[0120] In some embodiments, the bias power during the first cleaning is 10W to 30W. For example, the bias power can be 10W, 11W, 12W, 15W, 18W, 19W, 20W, 22, 24W, 26W, 28W, 29W, or 30W, or any value between any two of the aforementioned power values. The bias power can be set to remain continuously on to enhance the cleaning efficiency in a non-pulsating manner to thoroughly remove the carbon-based protective layer and generate a certain bombardment effect on the sidewall surface to remove weakly bonded residues on the sidewall (e.g., residual RuO to be cleaned). x / RuCl y Or reduced ruthenium, etc.

[0121] In some embodiments, the time for the first cleaning is 5s to 15s. For example, the time can be 5s, 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s, 14s, or 15s, or any value between any two of the aforementioned time values. The time is...

[0122] Thus, through the coordinated control of the above-mentioned flow ratio, flow rate, temperature, pressure, source power, bias power, time, etc., the carbon-based protective layer and oxide layer on the sidewall can be completely removed.

[0123] In a second aspect, embodiments of this application also provide a semiconductor structure obtained using a metal wire manufacturing method as provided in any of the embodiments of the first aspect above.

[0124] refer to Figure 10 In some embodiments, the semiconductor structure is disposed on the substrate 10. The substrate 10 has ruthenium metal lines 111 (metal lines of ruthenium material) on its surface. The ruthenium metal lines 111 are obtained by cyclically performing the first etching, carbon-based protective layer deposition, second etching, and third etching processes on the ruthenium metal layer 11 (metal layer of ruthenium material) as described above. After each predetermined number of third etchings, the sidewalls of the formed trench intermediate structure are cleaned in a second manner, and after the etching is completed, the sidewalls of the completed trench structure 17 (the sidewalls of the ruthenium metal lines 111) are cleaned in a first manner.

[0125] In some embodiments, a mask 12 may be present on the top of the ruthenium metal wire 111.

[0126] In a third aspect, embodiments of this application also provide a plasma processing apparatus for performing the metal wire manufacturing method corresponding to the above embodiments to form the semiconductor structure corresponding to the above embodiments. The plasma processing apparatus includes inductively coupled plasma (ICP) etching equipment or capacitively coupled plasma (CCP) etching equipment, etc.

[0127] In other aspects, embodiments of this application also provide an electronic device, including a semiconductor structure obtained using the metal wire manufacturing method of the above embodiments. The electronic device can be a storage device, mobile phone, computer, tablet computer, electronic instrument, television, artificial intelligence device, etc.

[0128] In summary, this embodiment of the application forms ruthenium metal lines 111 by periodically etching the ruthenium metal layer using a first etching cycle, followed by deposition of a carbon-based protective layer, a second etching cycle, and a third etching cycle. By depositing a carbon-based protective layer 14 on the inner wall of the trench structure formed during the etching process, the sidewalls are isolated and protected, ensuring etching uniformity and perpendicularity. This keeps the sidewall surface smooth and significantly reduces non-volatile byproducts (RuO₂). x / RuCl y The probability of deposition and residue on the sidewalls is reduced. By performing a second cleaning of the middle structure of the trench after each preset number of third etchings, the formation of a "micromask" due to long-term residue of the product is prevented, which would cause random unevenness on the sidewalls during further etching, resulting in poor sidewall roughness. This ensures that the sidewalls maintain a low roughness during further etching, improves linewidth uniformity, significantly reduces the risk of short circuits or open circuits, and greatly reduces overlay errors. It also ensures good connection with the upper metal vias. Finally, by performing a first cleaning on the sidewalls of the obtained ruthenium metal line 111 (the sidewalls of the completed trench structure 17), a more ideal nucleation surface is provided for the subsequent deposition of the film. Therefore, the embodiments of this application can improve the sidewall roughness problem from the source during the etching process, so that the etching process can continue to proceed steadily downwards. This enables the realization of ruthenium metal lines with higher aspect ratio and higher interconnect density, greatly reducing the risk of short circuit or open circuit, achieving lower resistance and interconnect stability, and well meeting the technical requirements of advanced nodes.

[0129] The above are merely preferred embodiments of this application. These embodiments are not intended to limit the scope of protection of this application. Therefore, any equivalent changes made based on the description and drawings of this application should also be included within the scope of protection of this application.

Claims

1. A method for manufacturing a metal wire, characterized in that, include: Provide substrate; A metal layer is formed on the surface of the substrate, and the metal layer material is ruthenium; The surface of the metal layer is first etched using oxygen-containing gas and chlorine-containing gas to form a trench intermediate structure on the metal layer. A carbon-based protective layer is deposited on the inner wall of the intermediate structure of the trench using a hydrocarbon-containing gas. Using oxygen-containing gas, the carbon-based protective layer on the bottom of the trench intermediate structure is etched a second time to remove it, and the surface of the ruthenium material exposed on the bottom is oxidized to form a ruthenium dioxide surface layer. The ruthenium dioxide surface layer formed on the bottom is removed by a third etching using oxygen-containing gas and chlorine-containing gas to expose the surface of the underlying ruthenium material for the first etching to be performed again. The first etching, deposition of the carbon-based protective layer, the second etching, and the third etching are repeated sequentially until a through trench completion structure evolved from the trench intermediate structure is formed on the metal layer, so as to form multiple metal lines divided by the trench completion structure on the surface of the substrate. Additionally, hydrogen-containing gas is used for cleaning the trench sidewalls.

2. The method for manufacturing metal wire according to claim 1, characterized in that, The method of cleaning the trench sidewalls using hydrogen-containing gas specifically includes: using hydrogen-containing gas to perform a first cleaning on the sidewalls of the completed trench structure to remove the carbon-based protective layer and the oxide layer present on the sidewalls.

3. The method for manufacturing metal wire according to claim 1, characterized in that, The method of using hydrogen-containing gas to clean the trench sidewalls specifically includes: after each preset number of third etching operations, using hydrogen-containing gas to perform a second cleaning on the sidewalls of the intermediate structure of the trench, in order to reduce any residual products.

4. The method for manufacturing metal wire according to claim 1, characterized in that, During the third etching process, a chlorine-containing gas is added to the oxygen-containing gas to react with the ruthenium dioxide surface layer and generate volatile RuO. x Cl y A complex is used to remove the ruthenium dioxide surface layer.

5. The method for manufacturing metal wire according to claim 1, characterized in that, During the first etching, the chlorine gas flow rate to oxygen gas flow rate is 1:10 to 3:10, the total flow rate of the oxygen and chlorine gases is 50 sccm to 300 sccm, the temperature is 20°C to 60°C, the pressure is 5 mTorr to 50 mTorr, the source power is 300 W to 800 W, the bias power is 10 W to 100 W, and the time is 0.1 s to 15 s; and / or, during the deposition of the carbon-based protective layer, a first dilution gas is also added to the hydrocarbon-containing gas, the hydrocarbon gas flow rate to first dilution gas flow rate is 1:4 to 1:6, the total flow rate of the hydrocarbon and first dilution gas is 50 sccm to 300 sccm, the temperature is 20°C to 60°C, the pressure is 10 mTorr to 100 mTorr, and the source power is 100 W to 50 W. 0W, bias power of 0W to 20W, time of 0.1s to 5s; and / or, during the second etching, the oxygen-containing gas flow rate is 30sccm to 200sccm, the temperature is 20℃ to 60℃, the pressure is 5mTorr to 50mTorr, the source power is 200W to 600W, the bias power is 10W to 60W, and the time is 0.1s to 5s; and / or, during the third etching, the chlorine-containing gas flow rate: oxygen-containing gas flow rate = 1:10 to 3:10, the total flow rate of oxygen-containing gas and chlorine-containing gas is 20sccm to 200sccm, the temperature is 20℃ to 60℃, the pressure is 5mTorr to 50mTorr, the source power is 300W to 800W, the bias power is 50W to 120W, and the time is 0.1s to 8s.

6. The method for manufacturing metal wire according to claim 2, characterized in that, During the first cleaning process, a second diluent gas is added to the hydrogen-containing gas. The ratio of the hydrogen-containing gas flow rate to the second diluent gas flow rate is 1:4 to 1:

6. The total flow rate of the hydrogen-containing gas and the second diluent gas is 200 sccm to 1000 sccm. The temperature is 20℃ to 60℃, the pressure is 50 mTorr to 500 mTorr, the source power is 200 W to 600 W, the bias power is 10 W to 30 W, and the time is 5 s to 15 s.

7. The method for manufacturing metal wire according to claim 3, characterized in that, During the second cleaning process, a third dilution gas is added to the hydrogen-containing gas. The ratio of hydrogen-containing gas flow rate to third dilution gas flow rate is 1:4 to 1:

6. The total flow rate of the hydrogen-containing gas and the third dilution gas is 100 sccm to 300 sccm. The temperature is 20℃ to 60℃, the pressure is 20 mTorr to 100 mTorr, the source power is 100W to 500W, the bias power is 0W, and the time is 0.1s to 5s.

8. The method for manufacturing metal wire according to claim 1, characterized in that, Oxygen-containing gases include O2 or O3; and / or, chlorine-containing gases include Cl2; and / or, hydrocarbon-containing gases include at least one of CH4, C2H4, and C3H6; and / or, hydrogen-containing gases include H2.

9. The method for manufacturing metal wire according to claim 3, characterized in that, The preset number of times is 5 to 10.

10. A semiconductor structure, characterized in that, Obtained using the metal wire manufacturing method as described in any one of claims 1-9.

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