Tungsten deposition method and plasma equipment

Abstract

The invention discloses a tungsten deposition method and plasma equipment, and the tungsten deposition method comprises the steps: providing a substrate which comprises a characteristic region; a deposition step: introducing deposition gas and auxiliary gas into the surface of the substrate; the deposition gas at least comprises a tungsten-containing precursor and a reducing gas, and depositing a tungsten material layer in the characteristic area; the auxiliary gas at least comprises nitrogen; at least one of an atomic layer-like deposition process, a pulse deposition process, an atomic layer deposition process or a chemical vapor deposition process is adopted in the deposition step.

Description

Technical Field

[0001] The present invention relates to the field of semiconductors, and particularly to a method for depositing tungsten and a plasma device. Background Art

[0002] In terms of storage devices, tungsten is mainly applied to word lines and contacts of 3D NAND. At present, the number of stacked layers of 3D NAND is increasing, and its corresponding feature region has a very high aspect ratio. The reduction of the feature region size brings great challenges to the deposition of tungsten in terms of both process and equipment.

[0003] In order to ensure the filling effect of tungsten, new treatment steps are usually introduced in the traditional deposition process to improve the uniformity and step coverage of tungsten deposition in the feature region. However, due to the addition of new steps, the entire process time is prolonged, and the number of substrates processed per unit time (WPH, wafer per hour) is reduced. Summary of the Invention

[0004] The purpose of the present invention is to accelerate the deposition rate of tungsten, shorten the deposition time of tungsten, and improve production capacity.

[0005] To achieve the above purpose, the present invention provides a method for depositing tungsten, including:

[0006] Providing a substrate, the substrate comprising a feature region;

[0007] Deposition step: introducing a deposition gas and an auxiliary gas onto the surface of the substrate; the deposition gas includes at least a tungsten precursor and a reducing gas, and depositing a tungsten material layer in the feature region; the auxiliary gas includes at least nitrogen;

[0008] The deposition step adopts at least one of an atomic layer deposition-like process, a pulse deposition process, an atomic layer deposition process, or a chemical vapor deposition process.

[0009] Optionally, the auxiliary gas further includes an inert gas, and the ratio of the nitrogen to the inert gas is greater than or equal to 0.5%.

[0010] Optionally, the flow rate of the nitrogen is 100 sccm - 3000 sccm.

[0011] Optionally, the flow rate of the inert gas is 1000 sccm - 10000 sccm.

[0012] Optionally, the time range of the deposition step is not less than 10 s.

[0013] Optionally, the pressure range of the deposition step is 5 Torr - 100 Torr.

[0014] Optionally, the feature region includes a recessed structure recessed downward from the substrate surface, and a tungsten material layer is deposited on the side wall and bottom of the recessed structure.

[0015] Optionally, before the deposition step, a treatment step is further included: introducing a treatment gas onto the substrate surface, the treatment gas including fluorine / chlorine-containing radicals and radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen, the flow rate range of the treatment gas being 1-50 sccm, and the radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen forming a tungsten growth inhibition region on the side wall of the recessed structure.

[0016] Optionally, the treatment step and the deposition step are repeatedly executed so that more parts of the recessed structure are filled.

[0017] Optionally, the process conditions of each treatment step are the same; or, the treatment time of each treatment step is gradually reduced and / or the pressure of each treatment step is gradually increased and / or the gas flow rate is gradually reduced.

[0018] Optionally, the time range of the treatment step is 0-180 s.

[0019] Optionally, the treatment gas is selected from one of SF 6 , NF 3 , HCl, fluorocarbons, fluorohydrocarbons, fluorine oxides, chlorocarbons, chlorohydrocarbons, chlorine oxides, or a mixed gas thereof.

[0020] Optionally, before the treatment step, a pre-deposition step is further included: introducing a pre-deposition gas and a pre-assist gas onto the substrate surface; the pre-deposition gas includes at least a tungsten precursor and a reducing gas, and a tungsten material layer is deposited on the side wall and bottom of the recessed structure; the assist gas includes at least nitrogen.

[0021] Optionally, through the pre-deposition step, a first tungsten material layer is deposited on the side wall and bottom of the recessed structure;

[0022] Through the treatment step, the radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen form a tungsten growth inhibition region with at least a partial region of the first tungsten material layer deposited on the side wall of the recessed structure;

[0023] Through the deposition step, a second tungsten material layer is deposited in the recessed structure after being treated by the treatment step, so that at least a partial region of the recessed structure is filled with tungsten.

[0024] Optionally, the pre-deposition step employs at least one of an atomic layer deposition-like process, a pulse deposition process, an atomic layer deposition process, or a chemical vapor deposition process; the deposition step employs at least one of an atomic layer deposition-like process, a pulse deposition process, an atomic layer deposition process, or a chemical vapor deposition process.

[0025] Optionally, the pre-assist gas further includes an inert gas.

[0026] Optionally, in the pre-assist gas, the flow rate of nitrogen is 100 sccm - 3000 sccm.

[0027] Optionally, the pressure range of the pre-deposition step is 1 Torr - 100 Torr.

[0028] Optionally, the aspect ratio of the recessed structure is greater than 50:1.

[0029] Optionally, the recessed structure is at least one of a hole-like structure or a groove-like structure.

[0030] Optionally, the feature region includes word lines.

[0031] The present invention also provides a plasma device, including:

[0032] A reaction chamber;

[0033] A susceptor, located in the reaction chamber, for carrying a substrate;

[0034] A remote plasma source, for exciting a process gas into plasma and then feeding it into the reaction chamber;

[0035] A controller, configured to execute the above-mentioned tungsten deposition method.

[0036] Compared with the prior art, the beneficial effects of the present invention at least include:

[0037] (1) In the present invention, a part of the inert gas introduced during the deposition of the tungsten material layer in the traditional method is replaced with nitrogen having the same flow rate. After replacement, the deposition rate of the tungsten material layer is significantly increased, the time of the deposition step is shortened, and the entire process has a higher substrate processing efficiency.

[0038] (2) The increase in the nitrogen flow rate in the assist gas is beneficial to reducing the surface roughness of the tungsten material layer. A low surface roughness indicates a high density of the tungsten material layer, which helps to improve the surface flatness of the subsequent deposition of the tungsten material layer and reduce the possible gaps inside the feature region when filling the feature region.

[0039] (3) Although adding nitrogen gas to the auxiliary gas will increase the sheet resistance and the tungsten material layer shows a higher resistivity, the present invention finds that by controlling the nitrogen gas flow rate within an appropriate range, the negative impact on the resistivity caused by the increase in nitrogen gas flow rate is extremely small, but it can greatly reduce the deposition time and accelerate the deposition rate. Therefore, the range of nitrogen gas flow rate defined in the present invention can balance the relationship between the accelerated deposition rate of the tungsten material layer and the reduction of electrical properties, which can not only reduce the time of the deposition step but also maintain good electrical properties of the tungsten material layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flowchart of the tungsten deposition method of the present invention.

[0041] Figure 2 It is a partial schematic diagram of a semiconductor substrate of the present invention.

[0042] Figure 3 It is a process schematic diagram of performing a processing step in the tungsten deposition method of the present invention.

[0043] Figure 4 It is a deposition rate curve diagram of the tungsten material layer.

[0044] In the figure, 100 - substrate, 101 - material layer, 102 - concave structure, 103 - barrier layer, 201 - tungsten growth inhibition region, 202 - first tungsten material layer, 203 - second tungsten material layer, 205 - gap. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0046] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0047] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0048] In order to fill a tungsten material layer in the feature region of a substrate, the conventional method usually introduces a tungsten precursor, a reducing gas, and an auxiliary gas into the feature region. The auxiliary gas is generally an inert gas such as argon, serving as a carrier gas. Through an atomic layer deposition-like process, a pulse deposition process, or a combination of an atomic layer deposition-like process / pulse deposition process and a chemical vapor deposition process, the reducing gas and the tungsten precursor are deposited in the feature region to form a tungsten material layer.

[0049] The inventors found that replacing part of the inert gas in the auxiliary gas with nitrogen can significantly accelerate the tungsten deposition rate, shorten the tungsten deposition time, and improve the production capacity. Based on this, as Figure 1 shown, the present invention provides a tungsten deposition method, including:

[0050] Step S1: Provide a substrate, and the substrate includes a feature region.

[0051] In some embodiments, the feature region is a recessed structure recessed downward from the surface of the substrate, and a tungsten material layer is deposited in the recessed structure. In some embodiments, the feature region is a wordline arranged in the horizontal direction, and a tungsten material layer is deposited on the surface of the wordline structure.

[0052] Step S2: Deposition step: Introduce a deposition gas and an auxiliary gas onto the surface of the substrate; the deposition gas at least includes a tungsten precursor and a reducing gas, and a tungsten material layer is deposited in the feature region; the auxiliary gas at least includes nitrogen.

[0053] The deposition step adopts at least one of an atomic layer deposition-like process, a pulse deposition process, an atomic layer deposition process, or a chemical vapor deposition process.

[0054] In some embodiments, the flow rate of nitrogen is 100 sccm - 3000 sccm.

[0055] In some embodiments, the auxiliary gas further includes an inert gas, the ratio of nitrogen to the inert gas is greater than or equal to 0.5%, and the flow rate of the inert gas is 1000 sccm - 10000 sccm.

[0056] In some embodiments, the time range of the deposition step is not less than 10 s.

[0057] In some embodiments, the pressure range of the deposition step is 5 Torr - 100 Torr.

[0058] As Figure 2 shown, a semiconductor substrate 100 of the present invention includes a material layer 101 on its surface. A plurality of recessed structures 102, i.e., characteristic regions, are formed on the material layer 101. The recessed structures 102 can be vias or trenches. The sidewalls and bottom walls of the recessed structures 102 include a barrier layer 103 (barrier layer), which can be, for example, a titanium nitride (TiN) layer. The material layer 101 can be a silicon-containing material, which can be, for example, one or more of silicon oxide, silicon nitride, and polysilicon. The material layer 101 can also be a laminate of two or more silicon-containing materials, which can be, for example, a laminate of alternating silicon oxide and silicon nitride layers, or a laminate of alternating silicon oxide and polysilicon layers.

[0059] When depositing a tungsten material layer in the recessed structure 102, more tungsten material will be deposited near the top opening of the recessed structure 102 compared to the bottom inside the recessed structure 102, forming a protrusion at the top opening. As the deposition process proceeds, the protrusion gradually grows, which may cause the top opening of the recessed structure 102 to be prematurely closed, resulting in a large gap inside the recessed structure 102. Therefore, to ensure the deposition effect of the tungsten material layer, a conformal suppression treatment step can be performed first to suppress the recessed structure 102, so as to prevent the top opening area of the recessed structure 102 from being pinched off during subsequent deposition.

[0060] As Figure 3 shown, after depositing a first tungsten material layer 202 in the recessed structure 102, a treatment step is performed. A treatment gas is introduced onto the surface of the substrate to treat the surface of the first tungsten material layer 202. The treatment gas includes fluorine / chlorine-containing radicals and at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen-containing radicals. The fluorine / chlorine-containing radicals in the treatment gas are used to etch the first tungsten material layer 202 in the top opening area of the recessed structure 102 to expand the size of the top opening area and prevent the inside of the recessed structure 102 from being prematurely closed during subsequent processes; at the same time, the radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen in the treatment gas form surface bonds on the surface of the first tungsten material layer 202. The region where the surface bonds are formed will delay the growth of the tungsten material layer in the subsequent deposition step, forming a tungsten material layer deposition delay region, i.e., a tungsten growth inhibition region 201, on the sidewalls of the recessed structure 102 Figure 3The dot regions on the sidewalls of the middle recessed structure 102). Optionally, the processing gas flow rate ranges from 1 to 50 sccm, and the time range of the processing step is from 0 to 180 s. By controlling the flow rate range of the processing gas and the introduction time of the processing gas in the processing step, the penetration depth of radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen into the recessed structure 102 can be controlled, and then the depth of the tungsten growth inhibition region 201 can be controlled. The presence of this surface bond delays / inhibits the deposition of the subsequent tungsten material layer at this position, but does not form an observable new film and does not affect the electrical properties of the semiconductor substrate 100. Optionally, the processing gas is selected from one of SF 6 , NF 3 , HCl, fluorocarbons, fluorohydrocarbons, fluorine oxides, chlorocarbons, chlorohydrocarbons, chlorine oxides, or a mixed gas thereof.

[0061] After the processing step is completed, a second tungsten material layer 203 is continuously deposited into the recessed structure. Due to the treatment of radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen in the processing gas during the processing step, a tungsten growth inhibition region 201 is formed on the sidewall surface at a certain depth downward from the top opening of the recessed structure 102. Tungsten material will preferentially deposit on the surface of the first tungsten material layer 202 in the middle and lower parts of the recessed structure 102, thereby realizing the downward movement and reduction, and disappearance of the gap 205 in the recessed structure 102.

[0062] Tungsten preferentially deposits at the bottom and the sidewalls near the bottom of the recessed structure, inhibiting the deposition of tungsten on the top and the sidewalls near the top of the recessed structure 102. Tungsten has different deposition effects at different positions in the depth direction of the recessed structure, resulting in a "gradient delay". However, since a processing step is inserted during the deposition process of the tungsten material layer, the process time of the entire tungsten deposition process is prolonged, and the number of substrate processes per unit time is reduced. Although by increasing the process pressure, the delay time in the processing step can be shortened, filling the recessed structure under high pressure will result in poor step coverage in the recessed structure, and more processing steps are required, which is still not conducive to improving the production capacity.

[0063] Based on this, after the processing step is completed, the deposition step provided by the present invention is carried out. While keeping the total flow rate of the auxiliary gas (such as an inert gas like Ar) in the prior art unchanged, part of the auxiliary gas is replaced with nitrogen. After replacement, the deposition rate of the tungsten material layer is significantly increased, and the time of the deposition step is shortened to make up for the prolongation of the entire process time caused by adding the processing step. The tungsten deposition method provided by the present invention still has a higher substrate processing efficiency even if a processing step is added.

[0064] In some embodiments, the process conditions of each processing step are the same; or, the processing time of each processing step is gradually reduced and / or the pressure of each processing step is gradually increased and / or the gas flow rate is gradually reduced.

[0065] In some embodiments, the processing step and the deposition step are repeatedly executed such that more parts of the recessed structure are filled.

[0066] In some embodiments, the tungsten deposition method provided by the present invention further includes a pre-deposition step before the processing step. Through the pre-deposition step, in the recessed structure 102 of the semiconductor substrate as shown in Figure 2 a first tungsten material layer 202 is first deposited on the barrier layer 103 as a tungsten nucleation layer. The pre-deposition step includes: introducing a pre-deposition gas and a pre-assist gas onto the substrate surface; the pre-deposition gas at least includes a tungsten-containing precursor and a reducing gas, and the first tungsten material layer 202 is deposited on the sidewalls and bottom of the recessed structure; the pre-assist gas at least includes nitrogen. Then, through the processing step, at least one of the free radicals containing carbon, sulfur, nitrogen, hydrogen, or oxygen forms a tungsten growth inhibition region with at least a partial region of the first tungsten material layer 202 deposited on the sidewalls of the recessed structure; and then through the deposition step, a second tungsten material layer 203 is deposited in the recessed structure after being processed by the processing step as a tungsten bulk layer, such that at least a partial region of the recessed structure is filled with tungsten. The processing step and the deposition step are repeatedly executed such that more parts of the recessed structure are filled until it is completely filled.

[0067] In some embodiments, the pre-assist gas only contains an inert gas and is used as a carrier gas. In other embodiments, in order to minimize the entire process time as much as possible, the pre-assist gas at least includes an inert gas and nitrogen. The flow rate of nitrogen is 100 sccm - 3000 sccm.

[0068] In some embodiments, the pressure range of the pre-deposition step is 1 Torr - 100 Torr.

[0069] In some embodiments, the pre-deposition step adopts an atomic layer deposition-like process or a pulse deposition process or a combination of an atomic layer deposition-like process / pulse deposition process and a chemical vapor deposition process; the deposition step adopts a chemical vapor deposition process.

[0070] The present invention also provides a plasma device, including: a reaction chamber; a pedestal located in the reaction chamber for carrying a substrate; a remote plasma source (RPS) for exciting a processing gas into a plasma and then sending it into the reaction chamber; and a controller configured to execute the above-mentioned tungsten deposition method.

[0071] Example 1

[0072] This example provides a method for depositing tungsten, including:

[0073] Step S1.1: Provide a substrate, and the substrate includes a feature region.

[0074] The feature region is a concave structure recessed downward from the surface of the substrate, and the concave structure is a via. The aspect ratio of the via structure is greater than 50:1.

[0075] Step S1.2: Deposition step: Introduce deposition gas and auxiliary gas onto the surface of the substrate; the deposition gas includes tungsten-containing precursor tungsten hexafluoride (WF 6 ) and reducing gas hydrogen (H 2 ), and deposit a tungsten material layer on the bottom and side walls of the via structure; the auxiliary gas includes nitrogen and argon. Among them, the flow rate of nitrogen is 1000 sccm, and the flow rate of argon is 1000 sccm - 10000 sccm. The deposition step adopts chemical vapor deposition process (CVD). The duration of the deposition step is at least 600 s.

[0076] Example 2

[0077] The difference between the method for depositing tungsten provided in this example and Example 1 is that in the deposition step, the flow rate of nitrogen is 3000 sccm.

[0078] Example 3

[0079] This example provides a method for depositing tungsten, including:

[0080] Step S3.1: Provide a substrate, and the substrate includes a feature region.

[0081] The feature region is a concave structure recessed downward from the surface of the substrate, and the concave structure is a via. The aspect ratio of the via structure is about 50:1.

[0082] Step S3.2: Predeposition step: Introduce predeposition gas and pre-auxiliary gas onto the surface of the substrate; the predeposition gas includes tungsten-containing precursor tungsten hexafluoride (WF 6 ) and reducing gas hydrogen (H 2 ), and deposit a first tungsten material layer on the side walls and bottom of the via structure; the auxiliary gas includes argon and nitrogen. Among them, the flow rate of nitrogen is 100 sccm, and the flow rate of argon is 1000 - 10000 sccm. The predeposition step adopts an atomic layer deposition-like process. Through the predeposition step, the thickness of the formed first tungsten material layer is

[0083] Step S3.3: Processing step: Introduce a processing gas onto the surface of the substrate. The processing gas includes fluorine / chlorine-containing radicals and radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen.

[0084] Etch the first tungsten material layer in the top opening region of the recessed structure 102 through the fluorine / chlorine-containing radicals to expand the size of the top opening region and prevent the interior of the recessed structure 102 from being prematurely closed in subsequent processes; form surface bonds on the surface of the tungsten material layer through radicals containing at least one of carbon, sulfur, nitrogen, hydrogen, or oxygen. The region where the surface bonds are formed will delay the growth of the tungsten material layer in the subsequent deposition step, and a tungsten material layer deposition delay region, i.e., a tungsten growth inhibition region 201, is formed on the sidewall of the recessed structure 102. The flow rate range of the processing gas is 1 sccm - 50 sccm, and the processing gas is selected from one of SF 6 , NF 3 , HCl, fluorocarbons, fluorohydrocarbons, fluorine oxides, chlorocarbons, chlorohydrocarbons, chlorine oxides, or a mixed gas thereof.

[0085] Step S3.4: Deposition step: Introduce a deposition gas and an auxiliary gas onto the surface of the substrate; the deposition gas includes tungsten-containing precursor tungsten hexafluoride (WF 6 ) and reducing gas hydrogen (H 2 ), and deposit a second tungsten material layer on the first tungsten material layer after being processed in the processing step; since in the processing step, a tungsten growth inhibition region 201 is formed on the sidewall surface at a certain depth downward from the top opening of the recessed structure 102, the tungsten material in the second deposition step preferentially deposits on the surface of the first tungsten material layer 202 in the middle and lower parts of the recessed structure 102. The auxiliary gas includes nitrogen and argon. Among them, the flow rate of nitrogen is 100 sccm, and the flow rate of argon is 1000 - 10000 sccm. The deposition step adopts a chemical vapor deposition process (CVD).

[0086] S3.5: Repeat the processing step and the deposition step until the hole structure is filled.

[0087] Example 4

[0088] The difference between the tungsten deposition method provided in this example and that in Example 3 is that in the pre-deposition step and the deposition step, the flow rate of nitrogen is 500 sccm.

[0089] Example 5

[0090] The difference between the tungsten deposition method provided in this example and that in Example 3 is that in the pre-deposition step and the deposition step, the flow rate of nitrogen is 1000 sccm.

[0091] Comparative Example

[0092] The difference between the tungsten deposition method provided by the comparative example and that of Example 1 is that in the deposition step, the auxiliary gas only includes argon, and the flow rate of argon is 1000 - 10000 sccm.

[0093] Measure the thicknesses of the tungsten material layers deposited in Example 1, Example 2, and the comparative example. With the deposition time as the abscissa and the thickness of the tungsten material layer as the ordinate, plot the deposition rate curves as shown in Figure 4 The slope of each curve is the deposition rate of the tungsten material layer. Figure 4 In the figure, the deposition rate curve of Example 1 is shown in green, the deposition rate curve of Example 2 is shown in red, and the deposition rate curve of the comparative example is shown in blue. It can be seen from this figure that within the same deposition time, the tungsten material layer of the comparative example 1 is the thinnest and the deposition rate is the slowest. The total flow rates of the auxiliary gases in Example 1, Example 2, and the comparative example 1 are the same. When part of the argon in the auxiliary gas is replaced with nitrogen with the same flow rate, as the flow rate of nitrogen gradually increases, the deposition thickness of the tungsten material layer within the same time gradually increases and the deposition rate speeds up. Compared with using only argon as the auxiliary gas, introducing nitrogen into the auxiliary gas and replacing part of the argon can improve the deposition rate of tungsten, reduce the process time for tungsten filling in high aspect ratio structures, and thus increase the number of substrates processed per unit time of the entire process.

[0094] Measure the deposition time, sheet resistance, and roughness of the tungsten material layers with a thickness of for Example 3, Example 4, Example 5, and the comparative example respectively. As shown in Table 1.

[0095] Table 1 Deposition time, sheet resistance, and roughness of the tungsten material layer

[0096]

[0097] According to Table 1, as the flow rate of nitrogen in the auxiliary gas increases, for depositing tungsten material layers with the same thickness, the deposition time used gradually decreases. Moreover, increasing nitrogen in the auxiliary gas is beneficial to reducing the surface roughness of the tungsten material layer. A low surface roughness indicates a high density of the tungsten material layer, which helps to improve the surface flatness of subsequent tungsten material layer deposition and reduce the possible gaps inside the groove structure when filling the groove structure. Specifically, when the flow rate ratio of nitrogen to the inert gas in the auxiliary gas is greater than or equal to 0.5%, the phenomenon that the addition of nitrogen reduces the deposition time of the tungsten material layer can be observed.

[0098] The addition of nitrogen will increase the square resistance, and the tungsten material layer will show a higher resistivity. In order to balance the relationship between the accelerated deposition rate of the tungsten material layer and the reduced electrical performance, the flow rate of nitrogen should be controlled within an appropriate range. As in Example 3-5, a tungsten recessed structure is deposited, and the recessed structure is a via. The aspect ratio of the via structure is about 50:1, and the thickness of the first tungsten material layer formed by the pre-deposition step is When the total thickness of the tungsten material layer is about In the case of , its square resistance Rs is not higher than 0.28Ω / sq, so the flow rate of nitrogen is not higher than 1000sccm. Under other process requirements and device performance requirements, such as depositing a tungsten material layer in a contact hole, the aspect ratio of the contact hole is about 15:1, and the thickness of the first tungsten material layer formed by the pre-deposition step is about The total thickness of the tungsten material layer is required to be about In this case, Rs is not higher than 1.3Ω / sq. At this time, the electrical performance requirements can be met under the condition that the nitrogen flow rate is not higher than 1500sccm, and the deposition rate can be accelerated. Optionally, the flow ratio of nitrogen to inert gas in the auxiliary gas does not exceed 30%, but the present invention is not limited thereto. The relationship between the nitrogen flow rate and the resistance of the tungsten material layer is balanced according to the actual process requirements and device performance requirements.

[0099] In summary, the present invention provides a tungsten deposition method, in which part of the inert gas introduced when depositing the tungsten material layer in the traditional method is replaced with nitrogen gas with the same flow rate, and the inert gas and nitrogen gas are used as auxiliary gases to be introduced into the surface of the substrate. After the replacement, the deposition rate of the tungsten material layer is significantly improved, the time of the deposition step is shortened, and the entire process has a higher substrate processing efficiency.

[0100] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for depositing tungsten, characterized in that, it includes: providing a substrate, the substrate comprising a feature region; a deposition step: introducing a deposition gas and an auxiliary gas onto the surface of the substrate; the deposition gas at least includes a tungsten-containing precursor and a reducing gas, and a tungsten material layer is deposited in the feature region; the auxiliary gas at least includes nitrogen; the deposition step adopts at least one of an atomic layer-like deposition process, a pulsed deposition process, an atomic layer deposition process or a chemical vapor deposition process.

2. The method for depositing tungsten according to claim 1, characterized in that, the auxiliary gas further includes an inert gas, and the ratio of the nitrogen to the inert gas is greater than or equal to 0.5%.

3. The method for depositing tungsten according to claim 2, characterized in that, the flow rate of the nitrogen is 100 sccm - 3000 sccm.

4. The method for depositing tungsten according to claim 2, characterized in that, the flow rate of the inert gas is 1000 sccm - 10000 sccm.

5. The method for depositing tungsten according to claim 1, characterized in that, the time range of the deposition step is not less than 10 s.

6. The method for depositing tungsten according to claim 1, characterized in that, the pressure range of the deposition step is 5 Torr - 100 Torr.

7. The method for depositing tungsten according to any one of claims 1 - 6, characterized in that, the feature region includes a concave structure recessed downward from the surface of the substrate, and a tungsten material layer is deposited on the side wall and bottom of the concave structure.

8. The method for depositing tungsten according to claim 7, characterized in that, before the deposition step, it further includes a treatment step: introducing a treatment gas onto the surface of the substrate, the treatment gas includes fluorine / chlorine-containing radicals and at least one of radicals containing carbon, sulfur, nitrogen, hydrogen or oxygen, the flow rate range of the treatment gas is 1 sccm - 50 sccm, and the at least one of radicals containing carbon, sulfur, nitrogen, hydrogen or oxygen forms a tungsten growth inhibition region on the side wall and opening of the concave structure.

9. The method for depositing tungsten according to claim 8, characterized in that, the treatment step and the deposition step are repeatedly executed so that more parts of the concave structure are filled.

10. The method for depositing tungsten according to claim 8, characterized in that, the process conditions of each treatment step are the same; or, the treatment time of each treatment step is gradually reduced and / or the pressure of each treatment step is gradually increased and / or the gas flow rate is gradually reduced.

11. The method for depositing tungsten according to claim 8, characterized in that, the time range of the treatment step is 0 - 180 s.

12. The method for depositing tungsten according to claim 8, characterized in that, The processing gas is selected from SF 6 , NF 3 , HCl, fluorocarbons, fluorohydrocarbons, fluorine oxides, chlorocarbons, chlorohydrocarbons, chlorine oxides, or a mixed gas thereof.

13. The method for depositing tungsten according to claim 8, characterized in that, before the treatment step, it further includes a pre-deposition step: introducing a pre-deposition gas and a pre-auxiliary gas onto the surface of the substrate; the pre-deposition gas at least includes a tungsten-containing precursor and a reducing gas, and a tungsten material layer is deposited on the side wall and bottom of the concave structure; the auxiliary gas at least includes nitrogen.

14. The method for depositing tungsten according to claim 13, characterized in that, Through the pre-deposition step, a first tungsten material layer is deposited on the sidewalls and bottom of the recessed structure; through the treatment step, at least a partial region of the first tungsten material layer deposited on the sidewalls of the recessed structure forms a tungsten growth inhibition region with at least one of the free radicals containing carbon, sulfur, nitrogen, hydrogen, or oxygen; through the deposition step, a second tungsten material layer is deposited in the recessed structure after being treated by the treatment step, so that at least a partial region of the recessed structure is filled with tungsten.

15. The tungsten deposition method according to claim 14, wherein, the pre-assist gas further includes an inert gas.

16. The tungsten deposition method according to claim 15, wherein, in the pre-assist gas, the flow rate of nitrogen is 100 sccm - 3000 sccm.

17. The tungsten deposition method according to claim 13, wherein, the pre-deposition step employs at least one of an atomic layer deposition-like process, a pulse deposition process, an atomic layer deposition process, or a chemical vapor deposition process; the deposition step employs at least one of an atomic layer deposition-like process, a pulse deposition process, an atomic layer deposition process, or a chemical vapor deposition process.

18. The tungsten deposition method according to claim 13, wherein, the pressure range of the pre-deposition step is 1 Torr - 100 Torr.

19. The tungsten deposition method according to claim 7, wherein, the aspect ratio of the recessed structure is greater than 50:

1.

20. The tungsten deposition method according to claim 1, wherein, the recessed structure is at least one of a hole-like structure or a groove-like structure.

21. The tungsten deposition method according to any one of claims 1 - 7, wherein, the characteristic region includes a word line.

22. A plasma device, wherein, comprising: a reaction chamber; a susceptor located in the reaction chamber for carrying a substrate; a remote plasma source for exciting a processing gas into a plasma and then feeding it into the reaction chamber; a controller configured to execute the tungsten deposition method according to any one of claims 1 - 21.

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