Semiconductor structure manufacturing method and semiconductor structure

Abstract

The embodiment of the invention discloses a semiconductor structure manufacturing method and a semiconductor structure, and the method comprises the steps: depositing a first part film layer of a first metal thin film layer on a substrate at a first temperature; a second temperature is adopted, the remaining second part of film layer of the first metal film layer is deposited on the first part of film layer, and the second temperature is a first variable temperature which is gradually increased between the first temperature and the fourth temperature; the formed first metal film layer is heated at a fifth temperature, and the fifth temperature is a second variable temperature which is gradually increased between the fourth temperature and the third temperature; and depositing a second metal thin film layer on the first metal thin film layer at a third temperature to form thin film layers of the same metal which are closely connected with each other. According to the embodiment of the invention, the film deposition quality is remarkably improved, the metal film layer with high film forming uniformity and high filling capacity can be obtained, and the efficiency is high.

Description

Technical Field

[0001] This application relates to the field of semiconductor processing technologies, and particularly to a method for fabricating a semiconductor structure and a semiconductor structure. Background Art

[0002] Tungsten deposition technology in integrated circuit manufacturing plays a key role in the filling of contact holes / vias, as well as in three-dimensional integrated circuits and advanced packaging. However, tungsten deposition technology still has significant defects in terms of film formation uniformity, fluorine contamination, high aspect ratio filling, stress control, etc. Among them, during the deposition of tungsten, due to poor film formation uniformity, the grains in the nucleation stage are relatively large and the distribution is relatively scattered and uneven, resulting in a problem of poor film adhesion ability, which affects the device quality. Therefore, it is necessary to study a process method that can significantly improve the film deposition quality when fabricating a semiconductor structure. Summary of the Invention

[0003] The purpose of this application is to overcome the above-mentioned technical problems existing in the existing tungsten deposition technology, and to provide a method for fabricating a semiconductor structure and a semiconductor structure, so as to significantly improve the film deposition quality when fabricating a semiconductor structure.

[0004] To achieve the above purpose, the technical solution of this application is as follows: According to the first aspect of this application, an embodiment of this application provides a method for fabricating a semiconductor structure, including: Providing a substrate; Depositing a first metal thin film layer on the substrate; Depositing a second metal thin film layer on the first metal thin film layer; Wherein, the first metal thin film layer and the second metal thin film layer are thin film layers of the same metal that are closely connected; First, depositing the first partial film layer of the first metal thin film layer at a first temperature, then depositing the remaining second partial film layer of the first metal thin film layer at a second temperature, and depositing the second metal thin film layer at a third temperature. The second temperature is a first variable temperature that gradually increases between the first temperature and a fourth temperature, and the fourth temperature is less than the third temperature; Before depositing the second metal thin film layer, the first metal thin film layer is also heat-treated at a fifth temperature. The fifth temperature is a second variable temperature that gradually increases between the fourth temperature and the third temperature.

[0005] In some embodiments, the first metal thin film layer is deposited using a first pressure, the second metal thin film layer is deposited using a second pressure, and the heating treatment is performed using a third pressure. The first pressure is less than the second pressure. The third pressure is a variable pressure with a gradually decreasing pressure between the first pressure and a fourth pressure. The fourth pressure is less than the first pressure and less than the second pressure.

[0006] In some embodiments, the first temperature is 50°C to 125°C lower than the third temperature.

[0007] In some embodiments, the first temperature is 300°C to 325°C.

[0008] In some embodiments, the third temperature is 350°C to 450°C.

[0009] In some embodiments, the fourth temperature is 325°C to 350°C.

[0010] In some embodiments, the first pressure is 5 Torr to 10 Torr.

[0011] In some embodiments, the second pressure is 50 Torr to 100 Torr.

[0012] In some embodiments, the fourth pressure is 1 Torr to 9 Torr.

[0013] In some embodiments, the first metal thin film layer and the second metal thin film layer are tungsten thin film layers. Among them, the first metal thin film layer is a nucleation layer, and the second metal thin film layer is a bulk deposition layer.

[0014] In some embodiments, the heating treatment is performed under a high thermal conductivity gas protection atmosphere.

[0015] In some embodiments, the high thermal conductivity gas includes at least one of helium and hydrogen.

[0016] In some embodiments, the high thermal conductivity gas is pure helium. When performing the heating treatment, the helium flow rate is 500 sccm to 1000 sccm, and the fourth pressure is 5 Torr to 9 Torr.

[0017] In some embodiments, the high thermal conductivity gas is pure hydrogen. When performing the heating treatment, the hydrogen flow rate is 1000 sccm to 1500 sccm, and the fourth pressure is 1 Torr to 2 Torr.

[0018] In some embodiments, the high thermal conductivity gas is a mixed gas of helium and hydrogen. When performing the heating treatment, the helium flow rate is 300 sccm to 1000 sccm, the hydrogen flow rate is 60 sccm to 300 sccm, and the fourth pressure is 3 Torr to 8 Torr.

[0019] In some embodiments, the ratio of the thickness of the first partial film layer to the thickness of the second partial film layer is 7:3 to 4:1.

[0020] In some embodiments, the ratio of the deposition time of the first partial film layer to the deposition time of the second partial film layer is 7:3 to 4:1.

[0021] In some embodiments, the first metal thin film layer and the second metal thin film layer are deposited in situ in the same cavity, and the heating treatment is performed in situ. According to the second aspect of the present application, embodiments of the present application further provide a semiconductor structure, which is obtained by using the semiconductor structure manufacturing method provided in any one of the embodiments of the first aspect above.

[0022] Embodiments of the present application may / at least have the following advantages: By depositing the first partial film layer of the first metal thin film layer at a relatively low temperature (the first temperature), the grain size in the initial nucleation stage can be reduced, and the film layer uniformity can be increased, so as to improve the adhesion ability between the first partial film layer as the bottom layer and the substrate surface (this also means an increase in trench filling ability), laying a good foundation for the subsequent film layer deposition.

[0023] By depositing the second partial film layer of the first metal thin film layer in a gradually increasing temperature manner, the post-nucleation stage can be utilized to pre-heat the already formed first partial film layer while depositing the second partial film layer. Therefore, on the premise of ensuring the continuity of temperature increase, the overall heating treatment time can be shortened, enabling the nucleation and bulk deposition stages to be completed relatively quickly at different temperatures, improving the efficiency, and using the special temperature increase method adopted during the deposition of the second partial film layer to make the grain size of the formed second partial film layer fall between the grain size of the first partial film layer and the grain size of the second metal thin film layer and gradually increase, thereby achieving a perfect connection in the microstructure between the nucleation layer (the first metal thin film layer) and the bulk deposition layer (the second metal thin film layer), and improving the uniformity of the overall film layer. By heating the first metal thin film layer before depositing the second metal thin film layer, the in-situ annealing of the first metal thin film layer can be realized by using the heating process before depositing the second metal thin film layer, so as to eliminate nucleation defects, promote grain fusion, provide a uniform substrate for bulk deposition, reduce thermal mismatch, and at the same time prepare for subsequent bulk deposition by heating. Moreover, since there is no need to use a dedicated heat treatment chamber (or other independent chambers in the same chamber) for annealing, the efficiency is improved while the cost is saved.

[0024] In summary, through the above-mentioned cooperative regulation method, the quality of thin film deposition is significantly improved, thus improving the existing tungsten deposition technology.

[0025] Other advantages of the present application will be elaborated in the following specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a flowchart of a method for fabricating a semiconductor structure according to a preferred embodiment of the present application.

[0026] Figure 2 It is a cross-sectional schematic diagram of a substrate structure in a method for fabricating a semiconductor structure according to a preferred embodiment of the present application.

[0027] Figure 3 It is a cross-sectional schematic diagram of a structure obtained after depositing the first part of the first metal thin film layer in a method for fabricating a semiconductor structure according to a preferred embodiment of the present application.

[0028] Figure 4 It is a cross-sectional schematic diagram of a structure obtained after depositing the second part of the first metal thin film layer in a method for fabricating a semiconductor structure according to a preferred embodiment of the present application.

[0029] Figure 5 It is a cross-sectional schematic diagram of a structure obtained after heat-treating the first metal thin film layer in a method for fabricating a semiconductor structure according to a preferred embodiment of the present application.

[0030] Figure 6 It is a cross-sectional schematic diagram of a structure obtained after depositing the second metal thin film layer in a method for fabricating a semiconductor structure according to a preferred embodiment of the present application.

[0031] Figure 7 It is a schematic structural diagram of a thin film deposition apparatus according to a preferred embodiment of the present application.

[0032] In the figure, 10. Substrate; 11. Groove; 12. Tungsten nucleation layer; 121. First part of the film layer; 122. Second part of the film layer; 13. Tungsten bulk deposition layer; 14. Tungsten thin film layer; 20. Chamber; 21. Gas source; 22. Spraying device; 23. Heating base. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] When tungsten thin films are deposited using existing tungsten deposition techniques, since the process always deposits tungsten thin films at the same relatively high temperature (e.g., 400 °C to 450 °C), problems such as poor film formation uniformity, relatively large and coarse grains in the nucleation stage, uneven and dispersed distribution, and poor film adhesion ability will occur. This problem easily causes defects in high aspect ratio filling holes / gaps due to poor final film formation uniformity, thus affecting the device quality.

[0034] In view of the above technical problems existing in the existing tungsten deposition techniques, the embodiments of the present application provide a method for fabricating a semiconductor structure, including: Providing a substrate; Depositing a first metal thin film layer on the substrate; Depositing a second metal thin film layer on the first metal thin film layer; Wherein, the first metal thin film layer and the second metal thin film layer are thin film layers of the same metal that are closely adhered to each other; First, deposit the first partial film layer of the first metal thin film layer at a first temperature, then deposit the remaining second partial film layer of the first metal thin film layer at a second temperature, and deposit the second metal thin film layer at a third temperature. The second temperature is a first variable temperature that gradually increases between the first temperature and a fourth temperature, and the fourth temperature is less than the third temperature; Before depositing the second metal thin film layer, heat-treat the first metal thin film layer at a fifth temperature. The fifth temperature is a second variable temperature that gradually increases between the fourth temperature and the third temperature.

[0035] Through the above method, the embodiments of the present application effectively solve the problems of poor film formation uniformity, relatively large and coarse grains in the nucleation stage, uneven and dispersed distribution, and poor film adhesion ability during the existing tungsten deposition process, significantly improve the film deposition quality, realize the improvement of the existing tungsten deposition technology, and thus can improve the device quality.

[0036] The following will describe the specific embodiments of the present application in detail with reference to the accompanying drawings.

[0037] Reference Figure 1 The embodiments of the present application provide a method for fabricating a semiconductor structure, including the following steps: Step S11: Providing a substrate.

[0038] Reference Figure 2。In some embodiments, the material for forming the substrate 10 may be single-crystalline silicon, polycrystalline silicon, amorphous silicon, doped silicon, or the like. The material of the substrate 10 may also be a SiGe substrate, a group III-V element compound substrate, a silicon carbide substrate, or a stacked structure thereof, or a silicon-on-insulator structure, or a diamond substrate, or other semiconductor material substrates known to those skilled in the art.

[0039] In some embodiments, an integrated circuit, such as a transistor structure, may be fabricated on the substrate 10.

[0040] In some embodiments, trenches 11 (contact holes / vias / through-silicon vias) may be fabricated on the substrate 10 to achieve the required vertical interconnection after metal filling of the trenches 11.

[0041] Step S12: Deposit a first partial film layer of the first metal thin film layer on the substrate at a first temperature.

[0042] In some embodiments, a first metal thin film layer and a second metal thin film layer are sequentially deposited on the surface of the substrate 10 in close contact to form a thin film layer of the same metal composed of the first metal thin film layer and the second metal thin film layer on the surface of the substrate 10.

[0043] In some embodiments, both the first metal thin film layer and the second metal thin film layer are thin film layers of tungsten. Among them, the first metal thin film layer is a tungsten nucleation layer, and the second metal thin film layer is a tungsten bulk deposition layer.

[0044] The following takes the case where both the first metal thin film layer and the second metal thin film layer are thin film layers of tungsten, the first metal thin film layer is a tungsten nucleation layer, and the second metal thin film layer is a tungsten bulk deposition layer as an example to detail the following embodiments of the present application.

[0045] Reference Figure 3 。First, deposit a first partial film layer 121 of the tungsten nucleation layer 12 as the first metal thin film layer on the surface of the substrate 10 at a relatively low first temperature.

[0046] It should be noted that a protective layer, a barrier layer, a hard mask layer, or the like may also be formed on the upper surface of the substrate 10 below the first partial film layer 121. The protective layer may be, for example, a silicon dioxide layer; the barrier layer may be, for example, titanium, titanium nitride, etc.; the hard mask layer may be, for example, a silicon dioxide layer, a silicon oxynitride layer, a silicon nitride layer, etc., or a combination thereof. For the convenience of highlighting the embodiments of the present application, the above-mentioned protective layer, barrier layer, hard mask layer, etc. are not shown and described in detail, but this does not mean that they cannot exist.

[0047] In some embodiments, when grooves 11 are formed on the surface of the substrate 10, the first partial film layer 121 is conformally deposited not only on the surface of the substrate 10 but also on the inner walls of the grooves 11.

[0048] In some embodiments, when grooves 11 are formed on the surface of the substrate 10, the barrier layer is also conformally deposited on the inner walls of the grooves 11, and the first partial film layer 121 is also conformally deposited on the inner walls of the grooves 11 within the barrier layer.

[0049] Reference Figure 7 . In some embodiments, a thin film deposition apparatus according to an embodiment of the present application is used to deposit a tungsten thin film layer on the substrate 10.

[0050] In some embodiments, a thin film deposition apparatus according to an embodiment of the present application includes a CVD deposition apparatus.

[0051] In some embodiments, the thin film deposition apparatus includes a chamber 20. Among them, a heating base 23 is provided on the bottom inside the chamber 20, and the horizontal surface of the heating base 23 is used to place the substrate 10. The heating base 23 is also used to heat the substrate 10 so that the substrate 10 is at a required process temperature for the deposition process. A spraying device 22 (spray head) is provided on the top inside the chamber 20. The spraying device 22 corresponds to the heating base 23 up and down and is used to spray a process gas onto the surface of the substrate 10 disposed on the heating base 23 to obtain a desired deposited film layer on the surface of the substrate 10. The process gas is input into the spraying device 22 through a gas source 21 connected to the spraying device 22 and further input into the chamber 20 through the spraying bottom surface of the spraying device 22.

[0052] In some embodiments, a heater is provided inside the heating base 23. By controlling the heater to start, the heating base 23 can be heated to a required target process temperature. In this way, by the heat conduction of the heating base 23, the substrate 10 can also be heated to the target process temperature.

[0053] In some embodiments, a cooling gas flow channel is further provided inside the heating base 23. The cooling gas flow channel is located between the heater and the top surface of the heating base 23. When a cooling gas (such as argon, etc.) is introduced into the cooling gas flow channel, it can play a role in cooling the back surface of the substrate 10 by forced convection to inhibit the heat transfer of the heating base 23.

[0054] Furthermore, by adjusting the flow rate of the cooling gas introduced into the cooling gas flow channel, the heat transfer ability of the heating base 23 can be adjusted so that the substrate 10 reaches different required temperatures.

[0055] In some embodiments, before the deposition process, by controlling the start of the heater, the heating base 23 is first heated to the target temperature and maintained, so that the substrate 10 located on the heating base 23 is heated to the target temperature. Then, by introducing a certain flow rate of cooling gas into the cooling gas flow channel, the substrate 10 is forced to convectively cool until it cools down to the first temperature required for depositing the tungsten nucleation layer 12, and the temperature of the substrate 10 is maintained at the first temperature. At this time, the deposition process of the first partial film layer 121 of the tungsten nucleation layer 12 is started, and the first partial film layer 121 of the tungsten nucleation layer 12 is deposited on the surface of the substrate 10. When the trench 11 is formed on the surface of the substrate 10, in addition to being deposited on the surface of the substrate 10, the first partial film layer 121 is conformally deposited on the inner wall of the trench 11, as Figure 3 shown.

[0056] In some embodiments, the first temperature used when depositing the first partial film layer 121 of the tungsten nucleation layer 12 is lower than the third temperature used when depositing the tungsten bulk deposition layer, and the first temperature is lower than the third temperature by 50 °C to 125 °C. For example, the first temperature can be 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C lower than the third temperature or any value between any two of the foregoing temperature values.

[0057] In some embodiments, the first temperature adopted when depositing the first partial film layer 121 is 300 °C to 325 °C. For example, the first temperature can be 300 °C, 305 °C, 310 °C, 315 °C, 320 °C, 325 °C or any value between any two of the foregoing temperature values.

[0058] In some embodiments, when depositing the first partial film layer 121, argon with a flow rate of 50 sccm to 100 sccm is continuously introduced into the cooling gas flow channel as the cooling gas. For example, the flow rate of argon can be 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm or any value between any two of the foregoing flow rate values (the cooling rate can reach 10 °C / s to 20 °C / s).

[0059] In some embodiments, the first partial film layer 121 is deposited at the first pressure.

[0060] In some embodiments, the first pressure is 5 Torr to 10 Torr. For example, the first pressure can be 5 Torr, 5.5 Torr, 6 Torr, 6.5 Torr, 7 Torr, 7.5 Torr, 8 Torr, 8.5 Torr, 9 Torr, 9.5 Torr, 10 Torr or any value between any two of the foregoing pressure values.

[0061] In some embodiments, the thickness of the first partial film layer 121 accounts for 70% to 80% of the total thickness of the tungsten nucleation layer 12. For example, the thickness of the first partial film layer 121 can be 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80% of the total thickness of the tungsten nucleation layer 12, or any value between any two of the aforementioned percentage values.

[0062] In some embodiments, the process gas used for depositing the tungsten nucleation layer 12 includes SiH 4 (or B 2 H 6 ), WF 6 ; the carrier gas includes N 2 or Ar. The process gas (including the carrier gas) is sprayed onto the cavity 20 through the spray bottom surface of the spraying device 22 and contacts the surface of the substrate 10 to react on the surface of the substrate 10 to form the required tungsten nucleation layer 12 and tungsten bulk deposition layer.

[0063] Step S13: Deposit the remaining second partial film layer of the first metal thin film layer on the first partial film layer at a second temperature, where the second temperature is a first variable temperature that gradually increases between the first temperature and the fourth temperature.

[0064] Refer to Figure 4 . On the same heating base 23 as above, at the second temperature, on the first partial film layer 121 of the deposited tungsten nucleation layer 12, in a continuous manner, continue to deposit to form the remaining second partial film layer 122 of the tungsten nucleation layer 12 other than the first partial film layer 121.

[0065] In some embodiments, by stopping the supply of the cooling gas to the cooling gas flow channel, the heater on the heating base 23 can resume direct heat transfer to the substrate 10, so that the temperature of the substrate 10 can be rapidly increased on the basis of the first temperature (the heating rate can be greater than or equal to 20 °C / s), so that the remaining second partial film layer 122 of the tungsten nucleation layer 12 is continuously deposited in situ on the formed first partial film layer 121 in a temperature range of a gradually increasing second temperature above the first temperature to complete the deposition of the entire tungsten nucleation layer 12. In other words, the process of depositing the first partial film layer 121 and the second partial film layer 122 of the tungsten nucleation layer 12 is a continuous and uninterrupted deposition process, and the heating base 23 is not replaced when depositing the second partial film layer 122. Moreover, the starting point of the second temperature when depositing the second partial film layer 122 is the first temperature when depositing the first partial film layer 121, and the end point of the second temperature when depositing the second partial film layer 122 is the fourth temperature higher than the first temperature, so that the second temperature is a variable temperature (the first variable temperature) that gradually increases between the first temperature and the fourth temperature.

[0066] In some embodiments, the end temperature of the temperature range of the second temperature, which is the first variable temperature, i.e., the fourth temperature, is 325°C to 350°C. For example, the fourth temperature can be 325°C, 330°C, 335°C, 340°C, 345°C, 350°C, or any value between any two of the aforementioned temperature values.

[0067] In some embodiments, the second temperature is the first variable temperature with a gradually increasing temperature between 300°C and 325°C. That is, the second part of the film layer 122 is continuously deposited on the first part of the film layer 121 during the process of the temperature of the heating base 23 gradually rising from the first temperature of 300°C to the fourth temperature of 325°C, and together with the first part of the film layer 121, forms the tungsten nucleation layer 12.

[0068] In some embodiments, the second temperature is the first variable temperature with a gradually increasing temperature between 300°C and 350°C, between 325°C and 350°C, between 300°C and 330°C, between 300°C and 340°C, between 310°C and 325°C, between 310°C and 335°C, or between 310°C and 350°C, etc., but not limited thereto.

[0069] In some embodiments, the second part of the film layer 122 of the tungsten nucleation layer 12 is deposited using the above-mentioned first pressure, that is, when depositing the entire tungsten nucleation layer 12, the first part of the film layer 121 and the second part of the film layer 122 are deposited using the same pressure.

[0070] In some embodiments, the thickness of the second part of the film layer 122 accounts for 20% to 30% of the total thickness of the tungsten nucleation layer 12. For example, the thickness of the second part of the film layer 122 can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30% of the total thickness of the tungsten nucleation layer 12, or any value between any two of the aforementioned percentage values. It can be understood that the sum of the thickness of the first part of the film layer 121 and the thickness of the second part of the film layer 122 is equal to the total thickness of the tungsten nucleation layer 12.

[0071] In some embodiments, the ratio of the thickness of the deposited first part of the film layer 121 to the thickness of the second part of the film layer 122 is 7:3 to 4:1.

[0072] In some embodiments, the ratio of the deposition time of the first part of the film layer 121 to the deposition time of the second part of the film layer 122 is 7:3 to 4:1.

[0073] When the deposition of the first part of the film layer 121 and the second part of the film layer 122 is completed according to the total thickness of the tungsten nucleation layer 12 set by the process, that is, a tungsten nucleation layer 12 composed of the first part of the film layer 121 and the second part of the film layer 122 deposited in sequence is formed on the substrate 10, as Figure 4 shown.

[0074] It should be noted that, compared with the existing tungsten nucleation layer deposition temperature (400°C to 450°C), in the embodiment of the present application, when depositing the first partial film layer 121 of the tungsten nucleation layer 12, a lower deposition temperature (300°C to 325°C) is adopted. Therefore, the grain size at the initial nucleation stage of the tungsten nucleation layer 12 deposited through the embodiment of the present application will be relatively small (compared with the existing tungsten nucleation layer deposition temperature of 400°C to 450°C), and the distribution is relatively uniform, which will be beneficial to improving the adhesion ability of the first partial film layer 121 of the tungsten nucleation layer 12 as the bottom layer, that is, improving the bonding force between the tungsten nucleation layer 12 and the substrate 10, and is beneficial to improving the filling ability of the trench 11, thereby laying a foundation for the subsequent film layer deposition.

[0075] Moreover, compared with the existing method of depositing the entire tungsten nucleation layer at a consistent deposition temperature, the embodiment of the present application particularly divides the deposition of the tungsten nucleation layer 12 into two consecutive steps of successively depositing the first partial film layer 121 and the second partial film layer 122, and by adopting a gradually increasing temperature method to deposit the remaining second partial film layer 122 of the tungsten nucleation layer 12, the grain size of the formed second partial film layer 122 can be gradually increased on the basis of the grain size of the first partial film layer 121, so as to form a relatively gentle transitional connection with the larger grain size of the tungsten body deposition layer (the second metal thin film layer) deposited at a higher temperature higher than the first temperature, thereby improving the overall uniformity of the tungsten film layer (nucleation layer and bulk deposition layer), being beneficial to stress control, and improving the trench filling ability under a high aspect ratio. Step S14: Heat-treat the formed first metal thin film layer at a fifth temperature, where the fifth temperature is a second variable temperature that gradually increases between the fourth temperature and the third temperature.

[0076] Reference Figure 5 On the same heating base 23 as above, heat-treat the tungsten nucleation layer 12 deposited on the substrate 10 as the first metal thin film layer at a fifth temperature. That is, through heating, in-situ annealing treatment is performed on the tungsten nucleation layer 12 to eliminate the residual stress in the tungsten nucleation layer 12 and eliminate fluorine contamination.

[0077] In some embodiments, by continuing to stop introducing the cooling gas into the cooling gas flow channel, the heater on the heating base 23 continues to directly transfer heat to the substrate 10, so that the temperature of the substrate 10 continues to rise based on the fourth temperature. When approaching the deposition temperature (the third temperature) of the tungsten body deposition layer, a smaller flow rate of the cooling gas is introduced into the cooling gas flow channel to reduce the cooling effect, so as to perform in-situ heat treatment on the entire tungsten nucleation layer 12 in a temperature range of a fifth temperature that gradually rises above the fourth temperature. In other words, the process of depositing the second partial film layer 122 of the tungsten nucleation layer 12 and heat-treating the tungsten nucleation layer 12 is a continuous and uninterrupted temperature rise process, and the substrate 10 is kept in a state of rising temperature on the same heating base 23. Moreover, the starting point of the fifth temperature during the heat treatment of the tungsten nucleation layer 12 is the fourth temperature when the deposition of the second partial film layer 122 is completed, and the end point of the fifth temperature when the heat treatment is completed is the third temperature higher than the fourth temperature and the first temperature, so that the fifth temperature is a variable temperature (the second variable temperature) with a gradually increasing temperature between the fourth temperature and the third temperature. The third temperature is the temperature during the subsequent deposition of the tungsten body deposition layer.

[0078] In some embodiments, the end temperature (the third temperature) during the heat treatment, which is also the temperature during the subsequent deposition of the tungsten body deposition layer, is 350°C to 450°C. For example, the third temperature can be 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C or any value between any two of the foregoing temperature values.

[0079] In some embodiments, when approaching the third temperature, argon with a flow rate less than or equal to 30 sccm is continuously introduced into the cooling gas flow channel as the cooling gas. For example, the flow rate of argon can be 30 sccm, 25 sccm, 20 sccm, 15 sccm, 10 sccm, 5 sccm or any value between any two of the foregoing flow rate values. It can be understood that when the flow rate of argon is 0 sccm, that is, when the introduction of argon into the cooling gas flow channel is stopped, the temperature of the substrate 10 will reach the heating set temperature of the heater under the direct heat transfer of the heating base 23, that is, the heating set temperature of the heater at this time is used as the third temperature.

[0080] In some embodiments, the third pressure is used to heat-treat the tungsten nucleation layer 12. Among them, the third pressure is a variable pressure with a gradually decreasing pressure between the first pressure and the fourth pressure. Moreover, the fourth pressure is less than the first pressure during the deposition of the tungsten nucleation layer 12, and the fourth pressure is less than the second pressure during the deposition of the tungsten body deposition layer, and the second pressure is greater than the first pressure.

[0081] In some embodiments, the pressure inside the cavity 20 is adjusted through a vacuum system on the cavity 20, such that a tungsten nucleation layer 12 is deposited under a first pressure, a tungsten bulk deposition layer is deposited under a second pressure, and an adjustment of gradually decreasing pressure is performed based on the first pressure, such that a heat treatment of the tungsten nucleation layer 12 is performed during a process of gradually decreasing pressure, and after the heat treatment is completed, pressurization is performed to deposit the tungsten bulk deposition layer under the second pressure.

[0082] In some embodiments, as the end pressure of the pressure range of the third pressure which is a variable pressure, i.e., the fourth pressure is 1 Torr to 9 Torr. For example, the fourth pressure can be 1 Torr, 1.5 Torr, 2 Torr, 2.5 Torr, 3 Torr, 3.5 Torr, 4 Torr, 4.5 Torr, 5 Torr, 5.5 Torr, 6 Torr, 6.5 Torr, 7 Torr, 7.5 Torr, 8 Torr, 8.5 Torr, 9 Torr or any value between any two of the foregoing pressure values.

[0083] In some embodiments, the third pressure is a variable pressure with a gradually decreasing pressure between 5 Torr and 1 Torr. That is, the heat treatment is completed during the process that the pressure inside the cavity 20 gradually decreases from a first pressure of 5 Torr to a fourth pressure of 1 Torr.

[0084] In some embodiments, the third pressure is a variable pressure with a gradually decreasing pressure between 10 Torr and 1 Torr, between 10 Torr and 2 Torr, between 10 Torr and 3 Torr, between 10 Torr and 8 Torr, between 10 Torr and 9 Torr, between 5 Torr and 2 Torr, between 5 Torr and 3 Torr, between 9 Torr and 5 Torr, between 9 Torr and 4 Torr, or between 8 Torr and 1 Torr, etc., but is not limited thereto.

[0085] In some embodiments, when performing the heat treatment, a high thermal conductivity gas is introduced into the cavity 20 through a spraying device 22 to perform the heat treatment under the protective atmosphere of the high thermal conductivity gas. When performing the heat treatment, the introduction of the film-forming process gas needs to be stopped.

[0086] In some embodiments, the high thermal conductivity gas includes at least one of helium and hydrogen.

[0087] In some embodiments, pure helium is used as the high thermal conductivity gas, and pure helium is introduced into the cavity 20 to perform the heat treatment under the protective atmosphere of helium.

[0088] In some embodiments, when performing the heat treatment under a helium protection atmosphere, the helium flow rate is 500 sccm to 1000 sccm. For example, the helium flow rate can be 500 sccm, 550 sccm, 600 sccm, 650 sccm, 700 sccm, 750 sccm, 800 sccm, 850 sccm, 900 sccm, 950 sccm, 1000 sccm, or any value between any two of the aforementioned flow rate values.

[0089] In some embodiments, when performing the heat treatment under a helium protection atmosphere, the fourth pressure is 5 Torr to 9 Torr. For example, the fourth pressure can be 5 Torr, 5.5 Torr, 6 Torr, 6.5 Torr, 7 Torr, 7.5 Torr, 8 Torr, 8.5 Torr, 9 Torr, or any value between any two of the aforementioned pressure values.

[0090] In some embodiments, pure hydrogen is used as the high thermal conductivity gas, and pure hydrogen is introduced into the cavity 20 to perform the heat treatment under a hydrogen protection atmosphere.

[0091] In some embodiments, when performing the heat treatment under a hydrogen protection atmosphere, the hydrogen flow rate is 1000 sccm to 1500 sccm. For example, the hydrogen flow rate can be 1000 sccm, 1100 sccm, 1200 sccm, 1300 sccm, 1400 sccm, 1500 sccm, or any value between any two of the aforementioned flow rate values.

[0092] In some embodiments, when performing the heat treatment under a hydrogen protection atmosphere, the fourth pressure is 1 Torr to 2 Torr. For example, the fourth pressure can be 1 Torr, 1.1 Torr, 1.2 Torr, 1.3 Torr, 1.4 Torr, 1.5 Torr, 1.6 Torr, 1.7 Torr, 1.8 Torr, 1.9 Torr, 2 Torr, or any value between any two of the aforementioned pressure values.

[0093] In some embodiments, a mixed gas of helium and hydrogen is used as the high thermal conductivity gas, and helium and hydrogen are introduced into the cavity 20 to perform the heat treatment under a mixed gas protection atmosphere of helium and hydrogen.

[0094] In some embodiments, when performing a heat treatment in a protective atmosphere of a mixed gas of helium and hydrogen, the helium flow rate is 300 sccm to 1000 sccm, and the hydrogen flow rate is 60 sccm to 300 sccm. For example, the helium flow rate can be 300 sccm, 400 sccm, 500 sccm, 600 sccm, 700 sccm, 800 sccm, 900 sccm, 1000 sccm, or any value between any two of the aforementioned helium flow rates. The hydrogen flow rate can be 60 sccm, 70 sccm, 80 sccm, 90 sccm, 100 sccm, 150 sccm, 180 sccm, 200 sccm, 250 sccm, 260 sccm, 300 sccm, or any value between any two of the aforementioned hydrogen flow rates.

[0095] In some embodiments, when performing a heat treatment in a protective atmosphere of a mixed gas of helium and hydrogen, the fourth pressure is 3 Torr to 8 Torr. For example, the fourth pressure can be 3 Torr, 3.5 Torr, 4 Torr, 4.5 Torr, 5 Torr, 5.5 Torr, 6 Torr, 6.5 Torr, 7 Torr, 7.5 Torr, 8 Torr, or any value between any two of the aforementioned pressure values.

[0096] It should be noted that when introducing the above-mentioned high thermal conductivity gas, it is necessary to preheat the high thermal conductivity gas first to avoid the temperature drop caused by the cold gas contacting the heating base 23. Preferably, the high thermal conductivity gas is preheated to 200 °C to 250 °C first, and then introduced into the cavity 20.

[0097] When performing a heat treatment on the deposited tungsten nucleation layer 12, by introducing the above-mentioned high thermal conductivity gas, heat conduction can be enhanced, the temperature rise can be accelerated, the surface defects of the film layer can be removed, and side reactions can be prevented. Moreover, by controlling the heat treatment process at a lower pressure gradually decreasing from the first pressure to the fourth pressure, the gas thermal resistance can be reduced, and the temperature rise rate of the substrate 10 can be increased. Thus, while realizing in-situ annealing, continuous temperature rise also prepares for the deposition of the subsequent tungsten bulk deposition layer.

[0098] It is worth noting that by adopting a gradually increasing temperature method to deposit the second partial film layer 122 of the first metal thin film layer, the late nucleation stage can be utilized to preheat (pre-anneal) the already formed first partial film layer 121 while depositing the second partial film layer 122. Therefore, on the premise of ensuring the continuity of temperature rise, the entire heat treatment time can be shortened, and the reaction kinetics can be adjusted through process parameters (such as pressure, gas flow rate, temperature) so that the nucleation and bulk deposition stages can be completed relatively quickly at different temperatures, improving the efficiency.

[0099] Moreover, by heating the tungsten nucleation layer 12 (the first metal thin film layer) before depositing the tungsten bulk deposition layer (the second metal thin film layer), in-situ annealing of the tungsten nucleation layer 12 can be achieved during the heating-up process before depositing the tungsten bulk deposition layer, thereby eliminating nucleation defects, promoting grain fusion, providing a uniform substrate for bulk deposition, reducing thermal mismatch, and at the same time preparing for subsequent bulk deposition through heating-up.

[0100] Furthermore, since there is no need to use a dedicated heat treatment chamber 20 (or other multi-station chambers in the same chamber 20) for annealing separately, not only the efficiency is improved, but also the production cost is saved.

[0101] In some embodiments, by setting a heating trigger point in the process menu of the thin film deposition equipment control system, according to the target film thickness value of the tungsten nucleation layer 12, the target deposition thickness or the target deposition time of the first part of the film layer 121 can be set to trigger the heating trigger point to heat up the substrate 10 in the middle and later stages of nucleation, implement pre-heating in advance, and at the same time complete the deposition of the remaining second part of the film layer 122, and a second part of the film layer 122 with gradually changing grain size from small to large is obtained, realizing good connection between the tungsten nucleation layer 12 and the subsequent tungsten bulk deposition layer.

[0102] After the heat treatment, a relatively uniform tungsten nucleation layer 12 can be obtained, as Figure 5 shown ( Figure 5 in which the tungsten nucleation layer 12 formed by the first part of the film layer 121 and the second part of the film layer 122 after heat treatment is represented by the same pattern. When there are grooves 11 on the substrate 10, the tungsten nucleation layer 12 will also conformally and firmly adhere to the inner wall surface of the grooves 11.

[0103] Step S15: Deposit a second metal thin film layer on the first metal thin film layer at a third temperature to form a film layer of the same metal in close contact.

[0104] Refer to Figure 6 . On the same heating base 23 as above, at a third temperature, a tungsten bulk deposition layer 13 as the second metal thin film layer is further deposited on the heat-treated tungsten nucleation layer 12.

[0105] In some embodiments, the process gas used for depositing the tungsten bulk deposition layer 13 includes H 2 、WF 6 .

[0106] In some embodiments, by controlling the flow rate of argon cooling gas continuously introduced into the cooling gas flow channel, the temperature of the substrate 10 is maintained at the third temperature at the end of the heat treatment, so as to continue the deposition of the tungsten bulk deposition layer 13 on the tungsten nucleation layer 12 of the substrate 10. When the groove 11 is formed on the surface of the substrate 10, in addition to being deposited on the tungsten nucleation layer 12 on the surface of the substrate 10, the tungsten bulk deposition layer 13 will completely fill the groove 11 inside the tungsten nucleation layer 12 and form good close contact with the tungsten nucleation layer 12 in the groove 11, as Figure 6 shown.

[0107] In some embodiments, the third temperature during the deposition of the tungsten bulk deposition layer 13 is 350 °C to 450 °C as described above. It can be understood that since the deposition temperature of the tungsten bulk deposition layer 13 is higher than the deposition temperature of the tungsten nucleation layer 12, the grain size of the obtained tungsten bulk deposition layer 13 will also be larger than the grain size of the tungsten nucleation layer 12. At the same time, the grain size of the tungsten nucleation layer 12 after the heat treatment will increase. And since the end temperature of the heat treatment is the deposition temperature of the tungsten bulk deposition layer 13, the grain size of the surface layer of the second part of the film layer 122 at the contact interface between the tungsten nucleation layer 12 and the tungsten bulk deposition layer 13 will be very close to the grain size of the tungsten bulk deposition layer 13 subsequently deposited at the above interface. And after further annealing carried out after the deposition of the tungsten bulk deposition layer 13 is completed, further fusion between grains will occur at the above interface, so that a dense tungsten thin film layer 14 with more uniform film quality and higher bonding degree between film layers can be obtained.

[0108] In some embodiments, the tungsten bulk deposition layer 13 is deposited under the second pressure, and the second pressure is greater than the first pressure and the third pressure.

[0109] In some embodiments, after the heat treatment is completed, the pressure in the cavity 20 is increased from the fourth pressure to the second pressure by pressurizing the cavity 20, so as to perform the deposition process of the tungsten bulk deposition layer 13. In some embodiments, the second pressure is 50 Torr to 100 Torr. For example, the second pressure can be 50 Torr, 55 Torr, 60 Torr, 65 Torr, 70 Torr, 75 Torr, 80 Torr, 85 Torr, 90 Torr, 95 Torr, 100 Torr or any value between any two of the foregoing pressure values.

[0110] The semiconductor structure with the tungsten thin film layer 14 obtained after depositing the tungsten bulk deposition layer 13, as Figure 6 shown.

[0111] The embodiments of the present application further provide a semiconductor structure, and the semiconductor structure is obtained by using the semiconductor structure manufacturing method provided in any one of the foregoing embodiments.

[0112] Reference Figure 6 In some embodiments, the semiconductor structure includes a substrate 10 and a tungsten thin film layer 14 formed on the substrate 10 by using the method for manufacturing a semiconductor structure according to the above embodiments. The tungsten thin film layer 14 includes a tungsten nucleation layer 12 deposited on the surface of the substrate 10 and a tungsten bulk deposition layer 13 in close contact with the tungsten nucleation layer 12.

[0113] In some embodiments, a trench 11 is further formed on the substrate 10. The tungsten nucleation layer 12 is also deposited on the inner wall of the trench 11, and the tungsten bulk deposition layer 13 fills the trench 11 within the tungsten nucleation layer 12 to form a tungsten thin film layer 14 that fills the trench 11.

[0114] In some embodiments, the semiconductor structure is applied to the fields of three-dimensional integrated circuits and three-dimensional advanced packaging, and the conductive trench formed on the substrate is used as a through-silicon via (TSV) or a vertical interconnection structure of contact holes on a 3D integrated circuit chip.

[0115] In a third aspect, an embodiment of the present application further provides a thin film deposition apparatus for depositing a tungsten thin film layer on a substrate, such as based on Figure 7 and Figures 2 - 6 the above embodiments described.

[0116] In other aspects, an embodiment of the present application further provides an electronic device, including the semiconductor structure according to the above embodiments or a semiconductor structure obtained by using the method for manufacturing a semiconductor structure according to the above embodiments. The electronic device may be a storage device, a mobile phone, a computer, a tablet computer, a television, an artificial intelligence device, etc.

[0117] In summary, in the embodiments of the present application, by depositing the first partial film layer 121 of the first metal thin film layer at a relatively low temperature (the first temperature), depositing the second partial film layer 122 of the first metal thin film layer in a gradually increasing temperature manner to form a nucleation layer (tungsten nucleation layer 12), and heating the first metal thin film layer before depositing the second metal thin film layer as a bulk deposition layer (tungsten bulk deposition layer 13), the problems of poor film formation uniformity, relatively large grains and dispersed distribution in the nucleation stage, and poor adhesion ability in the existing tungsten deposition process can be effectively solved, the improvement of the existing tungsten deposition technology is realized, the film deposition quality is significantly improved, a metal thin film layer with high film formation uniformity and strong filling ability can be obtained, and the efficiency is high.

[0118] The above are only the preferred embodiments of the present application. The embodiments are not intended to limit the protection scope of the present application. Therefore, all equivalent changes made by using the content of the specification and drawings of the present application should be included in the protection scope of the present application by the same token.

Claims

1. A method for manufacturing a semiconductor structure, characterized in that: include: providing a substrate; depositing a first metal thin film layer on the substrate; depositing a second metal thin film layer on the first metal thin film layer; Wherein, the first metal thin film layer and the second metal thin film layer are thin film layers of the same metal that are in close contact with each other; Firstly, a first portion of the first metal thin film layer is deposited at a first temperature, then a second portion of the remaining first metal thin film layer is deposited at a second temperature, and then the second metal thin film layer is deposited at a third temperature, wherein the second temperature is a first temperature change temperature gradually increasing between the first temperature and a fourth temperature, and the fourth temperature is lower than the third temperature; Before depositing the second metal film layer, the first metal film layer is further heated at a fifth temperature, where the fifth temperature is a second temperature change temperature that gradually increases between the fourth temperature and the third temperature.

2. The method for manufacturing a semiconductor structure according to claim 1, wherein: The first metal film layer is deposited using a first pressure, the second metal film layer is deposited using a second pressure, and the heat treatment is performed using a third pressure, the first pressure is less than the second pressure, the third pressure is a variable pressure in which the pressure gradually decreases between the first pressure and a fourth pressure, the fourth pressure is less than the first pressure, and the fourth pressure is less than the second pressure.

3. The method for manufacturing a semiconductor structure according to claim 1, wherein: The first temperature is 50°C to 125°C lower than the third temperature; or, the first temperature is 300°C to 325°C; or, the third temperature is 350°C to 450°C; or, the fourth temperature is 325°C to 350°C.

4. The method for manufacturing a semiconductor structure according to claim 2, wherein: The first pressure is 5 Torr to 10 Torr; and / or the second pressure is 50 Torr to 100 Torr; and / or the fourth pressure is 1 Torr to 9 Torr.

5. The method for manufacturing a semiconductor structure according to claim 1, wherein: The first metal film layer and the second metal film layer are tungsten film layers, wherein the first metal film layer is a nucleation layer, and the second metal film layer is a bulk deposition layer.

6. The method for manufacturing a semiconductor structure according to claim 4, characterized in that: The heating treatment is performed under a high thermal conductivity gas protective atmosphere.

7. The method for manufacturing a semiconductor structure according to claim 6, wherein: The high thermal conductivity gas includes at least one of helium and hydrogen.

8. The method for manufacturing a semiconductor structure according to claim 7, characterized in that: The high thermal conductivity gas is pure helium. When the heat treatment is performed, the helium flow rate is 500sccm~1000sccm, and the fourth pressure is 5Torr~9Torr; or, the high thermal conductivity gas is pure hydrogen. When the heat treatment is performed, the hydrogen flow rate is 1000sccm~1500sccm, and the fourth pressure is 1Torr~2Torr; or, the high thermal conductivity gas is a mixed gas of helium and hydrogen. When the heat treatment is performed, the helium flow rate is 300sccm~1000sccm, the hydrogen flow rate is 60sccm~300sccm, and the fourth pressure is 3Torr~8Torr.

9. The method for manufacturing a semiconductor structure according to claim 1, wherein: The ratio of the thickness of the first part of the film layer to the thickness of the second part of the film layer is 7:3 to 4:1, or the ratio of the deposition time of the first part of the film layer to the deposition time of the second part of the film layer is 7:3 to 4:1; and / or the first metal film layer and the second metal film layer are in-situ deposited in the same cavity, and the heat treatment is performed in-situ.

10. A semiconductor structure, characterized in that: The method for manufacturing a semiconductor structure is used as claimed in any one of claims 1 to 9.

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