Method for chemical vapor deposition of tungsten
By employing a two-step nucleation method and a cyclic deposition process, the problem of premature closure of the pores during tungsten deposition was solved, achieving high-quality tungsten filling without voids or gaps, thus improving the reliability and yield of semiconductor devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG ICSPROUT SEMICONDUCTOR CO LTD
- Filing Date
- 2026-03-25
- Publication Date
- 2026-05-29
AI Technical Summary
Existing chemical vapor deposition (CVD) tungsten processes, when filling high aspect ratio holes, suffer from rapid tungsten deposition reaction rates, leading to premature closure of the hole openings and ineffective diffusion to the bottom, resulting in internal voids or gap defects that affect device reliability and yield.
A two-step nucleation method combined with a cyclic deposition process is adopted. First, highly active nucleation sites are formed on the surface of the tungsten nitride layer using diborane. Then, a second tungsten nucleation layer is accumulated layer by layer through the cyclic reaction of silane and tungsten hexafluoride. Finally, the tungsten host layer is deposited in a mixed atmosphere of hydrogen and tungsten hexafluoride.
It significantly improves the conformability and thickness uniformity of the nucleation layer at the bottom of the contact hole, ensures seamless filling of the tungsten body layer, and enhances the reliability and manufacturing yield of semiconductor devices.
Smart Images
Figure CN122105352A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a method for chemical vapor deposition of tungsten. Background Technology
[0002] In semiconductor manufacturing processes, as critical device dimensions continue to shrink, the aspect ratios of vias and contact holes continue to increase, placing higher demands on the conformability and filling capability of filling materials. Tungsten (W), due to its high melting point, low resistivity, and excellent electromigration resistance, is widely used as a metallic material for filling high aspect ratio holes. It is typically deposited on porous semiconductor substrates using chemical vapor deposition to achieve interlayer interconnects or contacts.
[0003] However, existing chemical vapor deposition (CVD) tungsten processes face significant technical challenges when filling high aspect ratio cavities: due to the rapid deposition reaction rate of tungsten, the precursor gas preferentially reacts and deposits at the pore opening, leading to premature closure of the pore opening. This prevents the reacting gas from effectively diffusing to the bottom of the pore, thus forming internal voids (e.g., ...). Figure 1 (as shown) or gap 2 defect (such as Figure 2 As shown in the figure, these defects are exposed during the subsequent chemical mechanical planarization process, which seriously affects the reliability and yield of the device. Summary of the Invention
[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for chemical vapor deposition of tungsten, which solves the problem in the prior art that the high aspect ratio pores are not completely filled and are prone to voids and gaps due to premature closure of the pores during the tungsten deposition process.
[0005] To achieve the above and other related objectives, the present invention provides a method for chemical vapor deposition of tungsten, the method comprising:
[0006] S1: A semiconductor substrate is provided, and a WN layer is formed on the semiconductor substrate, the semiconductor substrate having a contact hole, and the WN layer is formed at least on the inner wall of the contact hole;
[0007] S2: Expose the semiconductor substrate to a B2H6 atmosphere, so that B2H6 is adsorbed onto the surface of the WN layer;
[0008] S3: Expose the semiconductor substrate to a WF6 atmosphere, so that the WF6 reacts with the adsorbed B2H6 to form a first tungsten nucleation layer on the WN layer;
[0009] S4: Expose the semiconductor substrate to a SiH4 atmosphere, so that SiH4 is adsorbed on the surface of the first tungsten nucleation layer;
[0010] S5: Expose the semiconductor substrate to a WF6 atmosphere, so that the WF6 reacts with the adsorbed SiH4 to form a second tungsten nucleation layer;
[0011] S6: Repeat steps S4 and S5 at least once until a second tungsten nucleation layer of a predetermined thickness is formed at the bottom of the contact hole;
[0012] S7: Expose the semiconductor substrate to a mixed atmosphere of H2 and WF6 to deposit a tungsten host layer on the second tungsten nucleation layer.
[0013] Optionally, in steps S3 to S6, the sum of the thicknesses of the first tungsten nucleation layer and the second tungsten nucleation layer formed at the bottom of the contact hole is more than 20% of the total depth of the contact hole.
[0014] Optionally, in step S2, the semiconductor substrate is exposed to the B2H6 atmosphere for 1 to 3 seconds.
[0015] Optionally, in step S4, the semiconductor substrate is exposed to the SiH4 atmosphere for 0.5 to 1 second.
[0016] Optionally, in step S5, the semiconductor substrate is exposed to the WF6 atmosphere for 1.5 to 3 seconds.
[0017] Optionally, in step S6, steps S4 and S5 are repeated 8 to 12 times.
[0018] Optionally, in step S7, the pressure in the reaction chamber is 1 Torr ~ 10 Torr.
[0019] Optionally, in step S7, the semiconductor substrate is exposed to a mixed atmosphere of H2 and WF6, and the deposition temperature for depositing the tungsten host layer on the second tungsten nucleation layer is 400°C to 500°C.
[0020] Optionally, after step S7, a step of rapidly thermally annealing the semiconductor substrate is further included.
[0021] Furthermore, the rapid thermal annealing process is carried out in a mixed atmosphere of H2 and N2, and the temperature of the rapid thermal annealing process is 600℃~800℃, and the time is 30 seconds~120 seconds.
[0022] As described above, the chemical vapor deposition method for tungsten of the present invention has the following beneficial effects: by employing a two-step nucleation method combined with a cyclic deposition process, that is, after forming a tungsten nitride layer that inhibits the growth rate of tungsten, firstly, diborane is adsorbed onto the surface of the tungsten nitride layer to form highly active nucleation sites, and then tungsten hexafluoride is introduced to react and generate a first tungsten nucleation layer. Subsequently, the cyclic steps of silane adsorption and reaction with tungsten hexafluoride are repeated multiple times to accumulate layer by layer to form a second tungsten nucleation layer with a preset thickness. Finally, a tungsten host layer is deposited in a mixed atmosphere of hydrogen and tungsten hexafluoride. This effectively solves the problems in the prior art where the nucleation layer is discontinuous or insufficiently thick at the bottom of high aspect ratio contact holes, leading to premature closure of the hole opening and the formation of voids or gaps in the tungsten host layer as a filling layer. It significantly improves the conformability and thickness uniformity of the nucleation layer at the bottom of the contact hole, ensuring that the subsequent tungsten host layer can seamlessly fill the entire contact hole from bottom to top, thereby obtaining a high-quality tungsten-filled structure without voids or gaps, and improving the reliability and manufacturing yield of semiconductor devices. Attached Figure Description
[0023] Figure 1 The diagram shows a cross-sectional structure with voids formed by chemical vapor deposition of tungsten in the prior art.
[0024] Figure 2 The image shown is a morphological diagram of a slit-structured surface formed by chemical vapor deposition of tungsten in the prior art.
[0025] Figure 3 The diagram shown is a flow chart of the chemical vapor deposition method for tungsten according to the present invention.
[0026] Figure 4 The diagram shows a cross-sectional structure formed by the chemical vapor deposition method of tungsten according to the present invention.
[0027] Component labeling explanation: 1 Void, 2 Gap, 10 Semiconductor substrate, 11 WN layer, 12 Tungsten nucleation layer, 13 Tungsten body layer, 14 Contact hole, S1~S7 Steps. Detailed Implementation
[0028] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.
[0029] Please see Figures 1 to 4It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0030] This embodiment provides a method for chemical vapor deposition of tungsten, such as... Figure 3 As shown, the method for chemical vapor deposition of tungsten includes:
[0031] S1: A semiconductor substrate is provided, and a WN layer is formed on the semiconductor substrate, the semiconductor substrate having a contact hole, and the WN layer is formed at least on the inner wall of the contact hole;
[0032] S2: Expose the semiconductor substrate to a B2H6 atmosphere, so that B2H6 is adsorbed onto the surface of the WN layer;
[0033] S3: Expose the semiconductor substrate to a WF6 atmosphere, so that the WF6 reacts with the adsorbed B2H6 to form a first tungsten nucleation layer on the WN layer;
[0034] S4: Expose the semiconductor substrate to a SiH4 atmosphere, so that SiH4 is adsorbed on the surface of the first tungsten nucleation layer;
[0035] S5: Expose the semiconductor substrate to a WF6 atmosphere, so that the WF6 reacts with the adsorbed SiH4 to form a second tungsten nucleation layer;
[0036] S6: Repeat steps S4 and S5 at least once until a second tungsten nucleation layer of a predetermined thickness is formed at the bottom of the contact hole;
[0037] S7: Expose the semiconductor substrate to a mixed atmosphere of H2 and WF6 to deposit a tungsten host layer on the second tungsten nucleation layer.
[0038] The chemical vapor deposition method for tungsten in this embodiment employs a two-step nucleation method combined with a cyclic deposition process. After forming a tungsten nitride (WN) layer to inhibit tungsten growth, diborane (B₂H₆) is first adsorbed onto the surface of the WN layer to form highly active nucleation sites. Then, tungsten hexafluoride (WF₆) is introduced to react and generate the first tungsten nucleation layer. Subsequently, the cyclic steps of adsorption and reaction of silane (SiH₄) with tungsten hexafluoride are repeated multiple times to accumulate layer by layer to form a second tungsten nucleation layer of a predetermined thickness. Finally, hydrogen (H₂) and tungsten hexafluoride are reacted... Depositing a tungsten host layer in a mixed atmosphere effectively solves the problems in existing technologies, such as premature closure of the orifice due to discontinuous or insufficient thickness of the nucleation layer at the bottom of high aspect ratio contact holes, and the formation of voids or gaps inside the tungsten host layer as a filling layer. It significantly improves the conformability and thickness uniformity of the nucleation layer at the bottom of the contact hole, ensuring that the subsequent tungsten host layer can seamlessly fill the entire contact hole from bottom to top. This results in a high-quality tungsten-filled structure without voids or gaps, improving the reliability and manufacturing yield of semiconductor devices.
[0039] The method for chemical vapor deposition of tungsten in this embodiment will be described in detail below with reference to the specific accompanying drawings and reaction formulas.
[0040] refer to Figure 4 First, step S1 is performed, in which a semiconductor substrate 10 is provided, and a WN layer 11 is formed on the semiconductor substrate 10. The semiconductor substrate has contact holes, and the WN layer is formed at least on the inner wall of the contact holes.
[0041] Specifically, the WN layer 11 is formed at least on the inner wall of the contact hole 14 to ensure that the WN layer 11 can fully cover the entire inner wall of the contact hole 14, including the bottom and sidewall areas. This provides a uniform and dense barrier layer foundation for the subsequent tungsten deposition process. Since WN material itself has the effect of inhibiting excessively rapid tungsten growth, its formation on the inner wall of the contact hole can effectively prevent premature deposition and sealing of tungsten in the orifice area during the subsequent B2H6 adsorption and WF6 reaction. At the same time, the WN layer 11, as a diffusion barrier layer, can also prevent device failure caused by the diffusion of tungsten into the surrounding medium. Furthermore, the complete coverage of the inner wall of the contact hole 14 by the WN layer 11 creates ideal surface conditions for the uniform adsorption of B2H6, allowing active sites to be evenly distributed on the bottom and sidewalls of the contact hole 14. This ensures the continuity and thickness uniformity of the subsequent first tungsten nucleation layer inside the contact hole 14, laying the technological foundation for achieving a void-free and gap-free filling of the contact hole 14.
[0042] refer to Figure 4 Next, step S2 is performed, in which the semiconductor substrate 10 is exposed to a B2H6 atmosphere, so that B2H6 is adsorbed onto the surface of the WN layer 11.
[0043] As an example, the time and flow rate of exposing the semiconductor substrate 10 to the B2H6 atmosphere in step S2 can be adjusted according to actual needs. As a preferred example, in this embodiment, the time for exposing the semiconductor substrate 10 to the B2H6 atmosphere in step S2 is set to 1 to 3 seconds, and the gas flow rate of B2H6 is, for example, 450 sccm. By increasing the time for exposing the semiconductor substrate 10 to the B2H6 atmosphere, it is avoided that if the exposure time is too short (e.g., less than 1 second), B2H6 molecules will have difficulty forming sufficient and uniform chemical adsorption at the bottom and sidewalls of the high aspect ratio contact hole 14, resulting in insufficient nucleation site density during the subsequent WF6 reaction, damage to the continuity of the tungsten nucleation layer, and thus affecting the filling quality. By optimizing the exposure time to 1 to 3 seconds, it is possible to ensure that B2H6 forms a sufficiently dense and uniformly distributed active site inside the hole of the contact hole 14, especially in the bottom region of the hole, providing ideal conditions for the subsequent WF6 reaction to generate a continuous and dense first tungsten nucleation layer.
[0044] Next, in step S3, the semiconductor substrate 10 is exposed to a WF6 atmosphere, which reacts with the adsorbed B2H6 to form a first tungsten nucleation layer on the WN layer 11.
[0045] Specifically, the chemical reaction formula (1) for step S3 is as follows:
[0046] B2H6+WF6 → W+HF+BF······(1)
[0047] Next, in step S4, the semiconductor substrate 10 is exposed to a SiH4 atmosphere, so that SiH4 is adsorbed onto the surface of the first tungsten nucleation layer.
[0048] As an example, the time and flow rate of exposing the semiconductor substrate 10 to the SiH4 atmosphere in step S4 can be adjusted according to actual needs. As a preferred example, in step S4, the time for exposing the semiconductor substrate 10 to the SiH4 atmosphere is 0.5 seconds to 1 second, and the SiH4 gas flow rate is, for example, 450 sccm. By increasing the time for exposing the semiconductor substrate 10 to the SiH4 atmosphere, a uniform adsorption layer can be formed on the surface of the first tungsten nucleation layer, providing an active surface for the subsequent WF6 reaction to generate the second tungsten nucleation layer.
[0049] Next, in step S5, the semiconductor substrate 10 is exposed to a WF6 atmosphere, which reacts with the adsorbed SiH4 to form a second tungsten nucleation layer.
[0050] As an example, the time and flow rate of exposing the semiconductor substrate 10 to the WF6 atmosphere in step S5 can be adjusted according to actual needs. As a preferred example, in step S5, the semiconductor substrate 10 is exposed to the WF6 atmosphere for 1.5 seconds to 3 seconds, so that the WF6 molecules can completely diffuse to the bottom of the contact hole 14 and react fully in the bottom region, forming a second tungsten nucleation layer of sufficient thickness and continuity at key locations, thereby ensuring the bottom-up filling effect of the subsequent tungsten body layer 13.
[0051] Specifically, the chemical reaction formula (2) for step S5 is as follows:
[0052] 3SiH4+2WF6 → 2W+3SiF4+6H2······(2)
[0053] refer to Figure 4 Then proceed to step S6, repeating steps S4 and S5 at least once, until a second tungsten nucleation layer of a predetermined thickness is formed at the bottom of the contact hole 14.
[0054] It should be noted that the first tungsten nucleation layer and all of the second tungsten nucleation layers together constitute the tungsten nucleation layer 12. Figure 4 The first tungsten nucleation layer and the second tungsten nucleation layer are not shown separately.
[0055] In semiconductor manufacturing, the nucleation quality at the bottom of the contact hole 14 directly determines the deposition behavior of the subsequent tungsten body layer 13. If the nucleation layer 12 at the bottom of the hole is missing or discontinuous, the subsequent H2 reduction of WF6 will lack a uniform growth starting point, causing tungsten to preferentially nucleate and grow on the sidewalls, leading to premature closure of the hole opening and the formation of voids at the bottom. As a preferred example, in this embodiment, in steps S3 to S6, the sum of the thicknesses of the first tungsten nucleation layer and the second tungsten nucleation layer formed at the bottom of the contact hole 14 is more than 20% of the total depth of the contact hole. This provides ideal surface conditions for the subsequent deposition of the tungsten body layer 13, allowing tungsten to fill the hole uniformly from the bottom upwards, avoiding bottom voids or sidewall gaps caused by poor nucleation. This ensures that the contact hole 14 achieves completely defect-free tungsten filling, significantly improving the electrical connection reliability and long-term stability of the device.
[0056] Specifically, the number of times steps S4 and S5 are repeated in step S6 can be set according to the process conditions and nucleation requirements. Preferably, in this embodiment, the number of times steps S4 and S5 are repeated in step S6 is set to 8 to 12. If the number of cycles is too small, the second tungsten nucleation layer may not accumulate sufficiently at the bottom of the contact hole 14, especially in areas with a high depth-to-width ratio, resulting in a thin nucleation layer 12 or even discontinuous coverage. Consequently, during the subsequent H2 reduction of WF6 main deposition process, the bottom of the hole lacks sufficient surface conditions, which can easily lead to premature closure of the hole opening and the formation of voids at the bottom. Controlling the number of cycles to within the range of 8 to 12 ensures that the second tungsten nucleation layer forms a sufficiently thick and continuous dense coverage at the bottom and sidewalls of the contact hole 14, thereby ensuring that the subsequent tungsten main layer 13 can uniformly fill the entire contact hole 14 from bottom to top, obtaining a high-quality tungsten-filled structure without voids or gaps.
[0057] refer to Figure 4 Next, step S7 is performed, in which the semiconductor substrate 10 is exposed to a mixed atmosphere of H2 and WF6, and a tungsten host layer 13 is deposited on the second tungsten nucleation layer.
[0058] Specifically, the chemical reaction formula (3) for step S7 is as follows:
[0059] 3H2+WF6 → W+ 6HF······(3)
[0060] As a preferred example, in step S7, the reaction chamber pressure is 1 Torr ~ 10 Torr, and the deposition temperature is 400℃ ~ 500℃. Firstly, regarding the deposition temperature, the high temperature of 400℃ to 500℃ significantly enhances the reactivity between WF6 and H2, improves the surface migration ability of tungsten atoms, and results in the deposited tungsten host layer 13 having better crystal quality and lower resistivity. Simultaneously, the high temperature environment helps the precursor gas to be evenly distributed inside the pores. Secondly, regarding the reaction chamber pressure, controlling the pressure within the low pressure range of 1 Torr ~ 10 Torr is because if the pressure is too high, the mean free path of gas molecules shortens, and WF6 and H2 will rapidly escape and be consumed at the bottom of the pores due to frequent collisions, leading to a significant decrease in the gas concentration at the bottom of the pores, causing incomplete reaction and insufficient filling. If the pressure is too low, insufficient reactant concentration may result in a low deposition rate, affecting process efficiency. By controlling the pressure within a moderately low range of 1 Torr to 10 Torr, the reactant gas can be fully diffused to the bottom of the contact hole 14 before the reaction occurs, thus avoiding bottom filling defects caused by incomplete reaction at the bottom of the hole. Through the synergistic combination of high temperature and low pressure, this step ensures the deposition rate of the tungsten main layer 13 while achieving uniform gas distribution and full reaction inside the deep hole, providing a key process guarantee for obtaining a void-free and gapless tungsten-filled structure.
[0061] Due to the inherent grain growth characteristics during tungsten deposition, minute grain boundary gaps or residual stress may still exist within the tungsten substrate 13, especially in the central region of the contact hole 14 or in locations with a large depth-to-width ratio. If these microscopic defects are not removed, they will be exposed during subsequent chemical mechanical planarization, affecting device reliability. As a preferred example, this embodiment includes a rapid thermal annealing process on the semiconductor substrate 10 after step S7. As a further example, the rapid thermal annealing is performed in a mixed atmosphere of H2 and N2, at a temperature of 600°C to 800°C, for a time of 30 to 120 seconds. Through rapid thermal annealing, tungsten atoms acquire sufficient migration energy at high temperatures, promoting the regrowth of tungsten grains and grain boundary migration, thereby closing any minute gaps that may exist in the deposited state and eliminating internal stress in the thin film. Specifically, under high-temperature conditions of 600℃~800℃, tungsten grains rearrange and grow, transforming the previously loosely packed grain structure into a more compact one, reducing the number of grain boundaries. This not only effectively closes any potential micro-gaps but also lowers the resistivity of the thin film. Furthermore, annealing in a mixed atmosphere of H2 and N2 can reduce any oxides that may be present on the surface of the tungsten layer, further improving the electrical properties of the contact interface.
[0062] In summary, the chemical vapor deposition method for tungsten of the present invention employs a two-step nucleation method combined with a cyclic deposition process. After forming a tungsten nitride layer that inhibits tungsten growth, highly active nucleation sites are first formed on the surface of the tungsten nitride layer using diborane adsorption. Then, tungsten hexafluoride is introduced to react and generate a first tungsten nucleation layer. This process is repeated multiple times through silane adsorption and reaction with tungsten hexafluoride, accumulating layer by layer to form a second tungsten nucleation layer of a predetermined thickness. Finally, a tungsten substrate layer is deposited in a mixed atmosphere of hydrogen and tungsten hexafluoride. This effectively solves the problems in the prior art where the nucleation layer is discontinuous or insufficiently thick at the bottom of high aspect ratio contact holes, leading to premature hole closure and voids or gaps within the tungsten substrate layer as a filling layer. It significantly improves the conformability and thickness uniformity of the nucleation layer at the bottom of the contact hole, ensuring that the subsequent tungsten substrate layer can seamlessly fill the entire contact hole from bottom to top. This results in a high-quality tungsten-filled structure without voids or gaps, improving the reliability and manufacturing yield of semiconductor devices. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.
[0063] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.
Claims
1. A method for chemical vapor deposition of tungsten, characterized in that, The method for chemical vapor deposition of tungsten includes: S1: A semiconductor substrate is provided, and a WN layer is formed on the semiconductor substrate, the semiconductor substrate having a contact hole, and the WN layer is formed at least on the inner wall of the contact hole; S2: Expose the semiconductor substrate to a B2H6 atmosphere, so that B2H6 is adsorbed onto the surface of the WN layer; S3: Expose the semiconductor substrate to a WF6 atmosphere, so that the WF6 reacts with the adsorbed B2H6 to form a first tungsten nucleation layer on the WN layer; S4: Expose the semiconductor substrate to a SiH4 atmosphere, so that SiH4 is adsorbed on the surface of the first tungsten nucleation layer; S5: Expose the semiconductor substrate to a WF6 atmosphere, so that the WF6 reacts with the adsorbed SiH4 to form a second tungsten nucleation layer; S6: Repeat steps S4 and S5 at least once until a second tungsten nucleation layer of a predetermined thickness is formed at the bottom of the contact hole; S7: Expose the semiconductor substrate to a mixed atmosphere of H2 and WF6 to deposit a tungsten host layer on the second tungsten nucleation layer.
2. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: In steps S3 to S6, the sum of the thicknesses of the first tungsten nucleation layer and the second tungsten nucleation layer formed at the bottom of the contact hole is more than 20% of the total depth of the contact hole.
3. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: In step S2, the semiconductor substrate is exposed to the B2H6 atmosphere for 1 to 3 seconds.
4. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: In step S4, the semiconductor substrate is exposed to the SiH4 atmosphere for 0.5 seconds to 1 second.
5. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: In step S5, the semiconductor substrate is exposed to the WF6 atmosphere for 1.5 to 3 seconds.
6. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: In step S6, steps S4 and S5 are repeated 8 to 12 times.
7. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: In step S7, the pressure in the reaction chamber is 1 Torr ~ 10 Torr.
8. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: In step S7, the semiconductor substrate is exposed to a mixed atmosphere of H2 and WF6, and the deposition temperature for depositing the tungsten host layer on the second tungsten nucleation layer is 400°C to 500°C.
9. The method for chemical vapor deposition of tungsten according to claim 1, characterized in that: After step S7, the process further includes a rapid thermal annealing treatment of the semiconductor substrate.
10. The method for chemical vapor deposition of tungsten according to claim 9, characterized in that: The rapid thermal annealing process is carried out in a mixed atmosphere of H2 and N2, and the temperature of the rapid thermal annealing process is 600℃~800℃, and the time is 30 seconds~120 seconds.