Cobalt metal thin film and preparation method therefor

Abstract

The present application relates to the technical field of semiconductors, and provides a cobalt metal thin film and a preparation method therefor. The method of the present invention comprises: putting a substrate into an inner cavity, and then reacting a cobalt source with a reaction gas in such a manner that CVD and ALD are carried out at the same time, thereby depositing a cobalt metal thin film on the substrate. The present application further provides a spraying assembly, which can fully diffuse and evenly mix the cobalt source and a reducing gas before deposition, reduce the influence of the non-uniformity of a reaction area and a gas phase diffusion effect on the uniformity of deposition, and improve the film thickness uniformity of the deposited thin film. In the present application, CVD and ALD processes are combined; compared with deposition by means of ALD alone, the growth rate of the cobalt metal thin film is higher; and compared with deposition by means of CVD alone, the prepared cobalt thin film has stable growth uniformity and relatively low film resistivity.

Description

Metallic cobalt thin film and preparation method thereof

[0001] The present application claims priority to the prior application filed with the China National Intellectual Property Office on June 24, 2024, and entitled "Metallic cobalt thin film and preparation method thereof", with the patent application number 202410813360.7. The entire contents of the above-mentioned prior application are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of semiconductors, and in particular to a metallic cobalt thin film and a preparation method thereof. BACKGROUND

[0003] With the continuous progress of chip manufacturing processes, the feature size effect begins to become apparent in the size range below 10 nm. In this case, the reduction in the size of metal wires leads to an increase in the resistance of traditional interconnection materials such as copper, a decrease in signal transmission speed, and an increase in signal delay, while cobalt has fine grains, fewer grain boundaries, low resistance, and weak diffusion, and can better maintain the stability and electrical properties of interconnection structures in small-size chip manufacturing. However, there are some problems in the preparation process of existing cobalt thin films, such as poor within-wafer uniformity of Co thin films prepared by chemical vapor deposition (CVD) growth method; and too long time spent in preparing cobalt thin films by atomic layer deposition (ALD) method.

[0004] SUMMARY

[0005] In view of the above problems existing in the prior art, the present application provides a metallic cobalt thin film and a preparation method thereof.

[0006] To solve the above problems, the present application provides the following technical solutions:

[0007] In a first aspect, the present application provides a preparation method of a metallic cobalt thin film, comprising: the method is applied in an inner cavity of a deposition device, a substrate is placed in the inner cavity, and the method is to make a cobalt source and a reaction gas react by using a CVD and ALD simultaneous method to deposit a metallic cobalt thin film on the substrate.

[0008] In an embodiment of the present application, the deposition device is provided with 2 or more than 2 balance carrier gas pipelines leading into the inner cavity, 1 or more than 1 CVD reaction gas and its carrier gas pipeline, and 1 or more than 1 ALD reaction gas and its carrier gas pipeline leading into the inner cavity through a plasma generator. When the balance carrier gas pipeline is connected to the cobalt source, it serves as the CVD cobalt source and its carrier gas pipeline or the ALD cobalt source and its carrier gas pipeline. At this time, the balance carrier gas serves as the carrier gas of the CVD cobalt source or the ALD cobalt source.

[0009] In the method, the CVD reaction gas and its carrier gas pipeline, the ALD reaction gas and its carrier gas pipeline, the plasma generator, the CVD cobalt source and its carrier gas pipeline, the ALD cobalt source and its carrier gas pipeline and the remaining balance carrier gas pipeline except the CVD cobalt source and its carrier gas pipeline and the ALD cobalt source and its carrier gas pipeline are kept in an open state, while the ALD cobalt source and its carrier gas pipeline and the ALD reaction gas and its carrier gas pipeline are opened or closed according to the needs of the ALD cycle, which includes: ALD cobalt source pulse, ALD cobalt source carrier gas purge, ALD reaction gas pulse, ALD reaction gas carrier gas purge.

[0010] In an embodiment of the present application, the deposition device is further provided with an inert gas pipeline which passes through the plasma generator and enters the inner cavity, and the output ports of the inert gas pipeline, the CVD reaction gas and its carrier gas pipeline, the ALD reaction gas and its carrier gas pipeline, the CVD cobalt source and its carrier gas pipeline, the ALD cobalt source and its carrier gas pipeline and the remaining balance carrier gas pipeline are all the same in diameter; under this condition, the gas flow of the carrier gas of the CVD cobalt source and the ALD cobalt source and the remaining balance carrier gas is equal, the flow of the CVD cobalt source and the ALD cobalt source is equal, the carrier gas flow of the CVD reaction gas and the ALD reaction gas is equal, and the flow of the CVD reaction gas and the ALD reaction gas is equal.

[0011] In an embodiment of the present application, the inert gas pipeline is used for plasma pretreatment of the substrate surface.

[0012] In an embodiment of the present application, the preparation method further comprises annealing treatment of the metal cobalt thin film.

[0013] In an embodiment of the present application, the CVD and the ALD are optionally started one after the other or simultaneously, and are optionally closed one after the other or simultaneously.

[0014] In an embodiment of the present application, the CVD and the ALD are simultaneously started and simultaneously closed, and the number of cycles of ALD deposition completed during the CVD is not less than 1.

[0015] In an embodiment of the present application, the CVD cobalt source and the ALD cobalt source are CCTBA, the CVD reaction gas and the ALD reaction gas are H2, and the carrier gas of the CVD reaction gas and the ALD reaction gas, the remaining balance carrier gas and the inert gas are all Ar.

[0016] In an embodiment of the present application, during the preparation of the metal cobalt thin film, the inner cavity deposition temperature is 100-200°C, the cavity pressure of the inner cavity is 8-12 torr during CVD and ALD; the flow rates of the CVD reaction gas and the ALD reaction gas H2 are 5000 sccm respectively, the flow rates of the carrier gas Ar of the CVD reaction gas and the ALD reaction gas are 1000 sccm respectively, the flow rates of the CVD cobalt source and the ALD cobalt source CCTBA are 0-30 sccm respectively, the flow rate of the carrier gas of the CVD cobalt source and the ALD cobalt source and the rest of the balance carrier gas Ar is 500 sccm, the power of the plasma generator is 1000 W, and the cobalt source CCTBA temperature is 45°C.

[0017] In an embodiment of the present application, the time of one cycle of the ALD is 15 s, including: the ALD cobalt source pulse time is 1 s, i.e. the ALD cobalt source opening time is 1 s; the carrier gas purge time of the ALD cobalt source is 4 s, i.e. the ALD cobalt source closing time is 4 s; the ALD reaction gas pulse time is 3 s, i.e. the ALD reaction gas opening time is 3 s; the carrier gas purge time of the ALD reaction gas is 7 s, i.e. the ALD reaction gas closing time is 7 s.

[0018] In an embodiment of the present application, the inner cavity of the deposition device is provided with a detachable spraying assembly, the spraying assembly includes a columnar sidewall and a first panel and a second panel connected to both ends of the columnar sidewall, the columnar sidewall has a thickness, 2 or more than 2 air ducts are dispersedly arranged in the columnar sidewall, one end of the air duct is open at the end of the columnar sidewall close to the second panel, a cobalt source delivery channel in a radial shape is arranged at the end of the columnar sidewall close to the first panel, the cobalt source delivery channel is used for introducing the CVD cobalt source and its carrier gas, the ALD cobalt source and its carrier gas, and the rest of the balance carrier gas, the first panel is divided into a plurality of fan-shaped areas by the cobalt source delivery channel, the fan-shaped areas include a plurality of arrayed through holes; the radial center of the cobalt source delivery channel is arranged as a gas mixing area with an opening facing the second panel, one end of the cobalt source delivery channel communicates with the gas mixing area; the other end of the cobalt source delivery channel communicates with the other end opening of the air duct; the second panel includes a plurality of spraying holes arranged in the circumferential direction and the radial direction, a substrate support frame is mounted at the end of the second panel away from the first panel; when the spraying assembly is installed in the inner cavity, the output ends of the CVD cobalt source and its carrier gas pipeline, the ALD cobalt source and its carrier gas pipeline, and the rest of the balance carrier gas pipeline are connected with one end opening of the air duct correspondingly;

[0019] In the preparation method of the metal cobalt thin film, the CVD reaction gas and its carrier gas and the ALD reaction gas and its carrier gas flow to the area between the first panel and the second panel through the through hole, the CVD cobalt source and its carrier gas and the ALD cobalt source and its carrier gas gather in the gas mixing area, diffuse and mix with the CVD reaction gas and its carrier gas and the ALD reaction gas and its carrier gas in the area between the first panel and the second panel, and then flow to the substrate through the spray hole.

[0020] In an embodiment of the present application, the pore size of the spray hole is smaller than the pore size of the through hole.

[0021] In a second aspect, the present application provides a metal cobalt thin film prepared by the method described above.

[0022] In a third aspect, the present application provides a composite thin film comprising the metal cobalt thin film, which comprises a composite substrate and a thin film layer, the thin film layer being the metal cobalt thin film, the composite substrate comprising a substrate layer and an isolation layer attached to the substrate layer, and the thin film layer being formed by coating on the isolation layer.

[0023] The material of the substrate layer can be selected from silicon, silicon on insulator (SOI), quartz, sapphire or silicon carbide.

[0024] In an embodiment of the present application, the material of the substrate layer is silicon.

[0025] In the present application, the thickness of the substrate layer is not limited and can be selected according to the product structure and the size of the substrate used.

[0026] In an embodiment of the present application, the material of the isolation layer can be selected from silicon dioxide, silicon oxynitride or silicon nitride.

[0027] In an embodiment of the present application, the material of the isolation layer is silicon dioxide.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] The application provides a metal cobalt film and a preparation method thereof. By combining a CVD method and an ALD method, in the preparation process of the metal cobalt film, the prepared Co film has a shorter growth time (compared with the ALD method), a better in-wafer growth uniformity (film thickness) (compared with the CVD method), and a lower film layer resistivity (compared with the CVD method). Meanwhile, the application provides a spraying assembly, which compresses the reduction reaction space of H2 and CCTBA to a local area between a first panel and a second panel, so that H2 can sufficiently reduce CCTBA in a smaller space, and directly replace 0-valence Co in an H2 atmosphere, reduces the influence of the non-uniformity of the reaction area and the gas phase diffusion effect on the deposition uniformity, and the design can effectively improve the uniformity of the pressure field above the substrate. The uniform pressure helps the mixed gas to uniformly flow to the surface of the substrate through the spraying holes of the second panel, avoids the non-uniform deposition caused by the too large pressure gradient, and improves the film thickness uniformity of the deposited film. BRIEF DESCRIPTION OF DRAWINGS

[0030] Fig. 1 is a schematic diagram of the structure of a deposition device according to the application;

[0031] Fig. 2 is an enlarged view of the top structure A of the deposition device according to the application;

[0032] Fig. 3 is a schematic diagram of the upper surface structure of the spraying assembly according to the application;

[0033] Fig. 4 is a schematic diagram of the internal structure of the spraying assembly according to the application;

[0034] Fig. 5 is a schematic diagram of the lower surface structure of the spraying assembly according to the application;

[0035] Fig. 6 is a schematic diagram of the installation position of the spraying assembly according to the application in the inner cavity of the deposition device;

[0036] BRIEF DESCRIPTION OF DRAWINGS: A-top structure, 1-outer cavity, 2-inner cavity, 3-plasma generator, 4-CVD reaction gas and its carrier gas pipeline, 5-inert gas pipeline, 6-ALD reaction gas and its carrier gas pipeline, 7-balance carrier gas pipeline, 8-substrate transmission channel, 9-substrate support frame, 10-gas outlet, 100-first panel, 200-second panel, 300-cobalt source delivery channel, 400-gas mixing area, 110-fan-shaped area, 111-through hole, 210-spraying hole, 500-columnar side wall, 600-ventilation pipeline. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application.

[0038] The ranges disclosed herein are intended to be "open" ranges, given the lower and upper limit of a range, the range is defined to exclude the endpoints. Such ranges are also intended to include any and all combinations of any of the claimed ranges, i.e., any lower limit can be combined with any upper limit to form a range.

[0039] It should be noted that in the description of the present application, "first", "second" should not be understood as indicating or implying relative importance, unless otherwise explicitly specified and limited.

[0040] The deposition apparatus used in the present application is shown in Figs. 1-2, which are cross-sectional views of the deposition apparatus and an enlarged schematic view of the top structure A. The deposition apparatus used in the present application mainly comprises an outer cavity 1 and an inner cavity 2 arranged inside the outer cavity. A plasma generator 3 is arranged above the outer cavity 1, the output end of the plasma generator 3 is in communication with the inlet of the inner cavity 2, and the input end of the plasma generator 3 is connected with one or more CVD reaction gas and carrier gas pipelines 4, one or more inert gas pipelines 5, and one or more ALD reaction gas and carrier gas pipelines. In the present embodiment, one CVD reaction gas and carrier gas pipeline 4, one inert gas pipeline 5, and one ALD reaction gas and carrier gas pipeline 6 are arranged. The inner cavity comprises an upper half 21 and a lower half 22 connected with each other, wherein the upper half 21 is in the shape of a cone with the upper part smaller than the lower part, and the lower half 22 is in the shape of a basin. The junction of the upper half 21 and the lower half 22 is a circular inner cavity middle part. Two or more balance carrier gas pipelines are arranged along the outer edge of the inner cavity middle part. In the present embodiment, six balance carrier gas pipelines 7 are arranged, which are installed between the outer cavity 1 and the inner cavity 2 and have output ends that enter the inner cavity middle part. It should be noted that the output ends of the six balance carrier gas pipelines 7 that enter the inner cavity middle part are arranged opposite to each other in pairs. Each balance carrier gas pipeline 7 can be connected to a cobalt source. When connected to a cobalt source, the balance carrier gas pipeline 7 serves as a CVD or ALD cobalt source and carrier gas pipeline. At this time, the balance carrier gas serves as the carrier gas of the CVD cobalt source or the ALD cobalt source. A substrate transport channel 8 is arranged on the left side of the outer cavity 1. The left end of the substrate transport channel 8 is a valve connected with a vacuum transfer chamber, and the right end of the substrate transport channel 8 is in communication with the inner cavity 2. A substrate support frame 9 is further arranged inside the inner cavity 2 and is detachably connected with the wall of the inner cavity. An exhaust port 10 is arranged at the bottom of the inner cavity, and a vacuum pump is connected to the exhaust port 10 for adjusting the pressure in the cavity.

[0041] It should be noted that the output ports of all the pipelines in the inner cavity 2, such as the CVD reaction gas pipeline and its carrier gas pipeline 4, the ALD reaction gas pipeline and its carrier gas pipeline 6, the inert gas pipeline 5, the CVD cobalt source pipeline and its carrier gas pipeline, the ALD cobalt source pipeline and its carrier gas pipeline, and the remaining balance carrier gas pipeline 7 except the CVD cobalt source pipeline and its carrier gas pipeline and the ALD cobalt source pipeline and its carrier gas pipeline, have the same diameters.

[0042] The application also designs a spraying assembly, as shown in FIGS. 3-5, which comprises a cylindrical side wall 500 and first and second panels 100 and 200 connected to both ends of the cylindrical side wall 500. The cylindrical side wall 500 has a thickness, and 2 or more than 2 air passage pipelines 600 are dispersedly arranged in the cylindrical side wall 500. In this embodiment, 6 air passage pipelines 600 are arranged. One end of the air passage pipeline 600 is open at the end of the cylindrical side wall 500 close to the second panel 200. A cobalt source delivery channel 300 in a radial pattern is arranged at the end of the cylindrical side wall 500 close to the first panel 100. The cobalt source delivery channel 300 is used for introducing CVD cobalt source and its carrier gas, ALD cobalt source and its carrier gas, and the remaining balance carrier gas. The first panel 100 is divided into a plurality of fan-shaped areas 110 by the cobalt source delivery channel 300, and the fan-shaped areas 110 comprise a plurality of arrayed through holes 111. The radial center of the cobalt source delivery channel 300 is arranged as a gas mixing area 400 open toward the second panel. One end of the cobalt source delivery channel 300 communicates with the gas mixing area 400. The other end of the cobalt source delivery channel 300 communicates with the other end of the air passage pipeline 600. The second panel 200 comprises a plurality of spraying holes 210 arranged in the circumferential and radial directions. A substrate support frame is mounted at the end of the second panel 200 away from the first panel 100.

[0043] As shown in FIG. 6, when the spraying assembly is installed in the inner cavity, the output ends of the CVD cobalt source pipeline and its carrier gas pipeline, the ALD cobalt source pipeline and its carrier gas pipeline, and the remaining balance carrier gas pipeline 7 except the CVD cobalt source pipeline and its carrier gas pipeline and the ALD cobalt source pipeline and its carrier gas pipeline are connected to the one end openings of the air passage pipelines 600. The output port diameters of the CVD cobalt source pipeline and its carrier gas pipeline, the ALD cobalt source pipeline and its carrier gas pipeline, and the remaining balance carrier gas pipeline 7 except the CVD cobalt source pipeline and its carrier gas pipeline and the ALD cobalt source pipeline and its carrier gas pipeline are consistent with the diameters of the cobalt source delivery channel 300 and the air passage pipelines 600.

[0044] The method for using the deposition equipment of the application is as follows:

[0045] First, the inner cavity 2 is heated to the deposition temperature, then vacuumized, and then the substrate is delivered to the inner cavity 2 through the substrate transmission channel 8, and the substrate is preheated, and then the inert gas pipeline 5 and the plasma generator 3 are opened at the same time, and the surface of the substrate is pretreated to reduce the oxygen content and impurity particles on the surface of the substrate; after the pretreatment, the plasma generator 3 and the inert gas pipeline 5 are closed.

[0046] Subsequently, if the metal cobalt film is prepared by CVD, the plasma generator 3, the six balanced carrier gas pipelines 7, the CVD reaction gas and its carrier pipeline 4 are opened at the same time, and the carrier gas flow of the six balanced carrier gas pipelines 7 is equal. Optionally, one of the balanced carrier gas pipelines 7 is connected to the cobalt source as the CVD cobalt source and its carrier pipeline, and after the reaction gas reacts with the cobalt source, the deposition on the surface of the substrate continues to form a metal cobalt film. After the deposition is completed, all the gas pipelines and the plasma generator are closed, and then the substrate is annealed. During the preparation process, the vacuum pump can discharge the excess cobalt source, CVD reaction gas and reaction by-products in the process reaction.

[0047] If the metal cobalt film is prepared by ALD, the plasma generator 3, the six balanced carrier gas pipelines 7, the ALD reaction gas and its carrier pipeline 6 (only the carrier gas of the ALD reaction gas) are opened at the same time, and the carrier gas flow of the six balanced carrier gas pipelines 7 is equal. The ALD method needs to repeat multiple ALD cycles to complete the preparation of the metal cobalt film. Each ALD cycle includes four parts: ALD cobalt source pulse, ALD cobalt source carrier purge, ALD reaction gas pulse, and ALD reaction gas carrier purge. The specific details of the ALD cycle are as follows: one of the balanced carrier gas pipelines 7 is connected to the cobalt source and is closed after a period of time (ALD cobalt source pulse), and then the ALD reaction gas is opened and maintained for a period of time before being closed (ALD reaction gas pulse, at this time the cobalt source molecules on the surface of the substrate react with the reaction gas to form metal cobalt), and then the ALD reaction gas is purged for a period of time (ALD reaction gas carrier purge), and then the next ALD cycle begins. During the entire process of preparing the metal cobalt film by the ALD method, the carrier gas flow in the balanced carrier gas pipeline 7 does not change, the carrier gas flow of the ALD reaction gas does not change, and the plasma generator 3 is always in an open state. During the preparation process, the vacuum pump can discharge the excess cobalt source, ALD reaction gas and reaction by-products in the process reaction. After the deposition is completed, all the gas pipelines and the plasma generator are closed, and the preparation process is ended, and then the substrate is annealed.

[0048] If the metal cobalt thin film is prepared by the CVD combined with ALD method, the CVD and ALD processes start and end at the same time. First, the plasma generator 3, the six balanced carrier gas pipelines 7, the CVD reaction gas and its carrier pipeline 4 (only the carrier gas of the CVD reaction gas), and the ALD reaction gas and its carrier pipeline 6 (only the carrier gas of the ALD reaction gas) are turned on at the same time. Then, one of the balanced carrier gas pipelines 7 is selected as the CVD cobalt source and its carrier pipeline. When the cobalt source is connected, the CVD process starts. When the CVD process starts, another balanced carrier gas pipeline 7 opposite to the CVD cobalt source and its carrier pipeline is selected as the ALD cobalt source and its carrier pipeline, and the ALD cycle process starts. When the CVD process ends, the ALD cycle process also ends at the same time. During the whole preparation process, the CVD reaction gas and its carrier pipeline 4, the ALD reaction gas and its carrier pipeline 6, the plasma generator 3, the CVD cobalt source and its carrier pipeline, the ALD cobalt source and its carrier pipeline, and the remaining balanced carrier gas pipelines 7 are kept in the open state. At the same time, the ALD cobalt source and its carrier pipeline and the ALD reaction gas and its carrier pipeline 6 are opened or closed according to the needs of the ALD cycle, that is, the CVD reaction gas and its carrier, the carrier gas of the ALD reaction gas, the plasma generator, the CVD cobalt source and its carrier, the carrier gas of the ALD cobalt source, and the remaining balanced carrier gas are kept in the open state, and the ALD cobalt source and the ALD reaction gas are opened or closed according to the needs of the ALD cycle. During the preparation process, the vacuum pump can discharge the excess cobalt source, CVD and ALD reaction gas, and reaction by-products in the process reaction. All gas pipelines and the plasma generator are closed, and the preparation process ends. Then, the substrate is annealed.

[0049] The deposition device provided in the present application can use the above three methods to prepare a metal cobalt thin film when the spray assembly is arranged or not arranged in the inner cavity.

[0050] The spray assembly provided in the present application has the following effects: the cobalt source and its carrier gas are gathered in a small range in the gas mixing area 400 and then diffused to the surrounding, mixed and reacted with the CVD reaction gas or the ALD reaction gas rectified by the through hole 111 of the first panel 100 in the space between the first panel and the second panel, and then uniformly dispersed by the spray holes of the second panel 200 and diffused downward to the surface of the substrate, thereby reducing the non-uniformity of the reaction area and reducing the influence of the gas phase diffusion effect on the deposition uniformity. Moreover, this design can effectively improve the uniformity of the pressure field above the substrate. The uniform pressure helps the mixed gas to uniformly flow to the surface of the substrate through the spray holes of the second panel, thereby avoiding the non-uniform deposition caused by the pressure gradient and improving the film thickness uniformity of the deposited thin film.

[0051] The deposition equipment with the above structure is used in the following examples of the present application, and a metal cobalt thin film is prepared on a Si substrate or a Si composite substrate by using CCTBA as a CVD cobalt source and an ALD cobalt source, using H2 as a CVD reaction gas and an ALD reaction gas, using Ar as a carrier gas of the CVD reaction gas and the ALD reaction gas, a balance carrier gas and an inert gas. The Si substrate or the Si composite substrate used in the present application is circular unless otherwise specified.

[0052] The formula used in the examples of the present application is as follows:

[0053] (1) Non-uniformity

[0054] First, the standard deviation s (stdev) is calculated according to the following formula:

[0055] s 2 = [(x1-x)2+(x2-x)2+…(xn-x)2] / n, x is the average value of the film thickness (THK), there are n samples, and x is the film thickness of a single point. n i

[0056] Then, the non-uniformity 1-sigma value can be calculated by the standard deviation s and the average film thickness x (average (nm)), that is:

[0057] 1-sigma = s / x*100%

[0058] (2) Resistivity p (μΩ·cm)

[0059] p = R*x / 10, R is the square resistance (Ω / □), and x is the average film thickness (average (nm)).

[0060] Example 1: Preparation of a metal cobalt thin film by a CVD method

[0061] The deposition equipment with the above structure is used in the following examples of the present application, and a metal cobalt thin film is prepared on a Si substrate or a Si composite substrate by using CCTBA as a CVD cobalt source and an ALD cobalt source, using H2 as a CVD reaction gas and an ALD reaction gas, using Ar as a carrier gas of the CVD reaction gas and the ALD reaction gas, a balance carrier gas and an inert gas. The Si substrate or the Si composite substrate used in the present application is circular unless otherwise specified.

[0062] 1. After heating the inner cavity to a deposition temperature, vacuumize, the deposition temperature is preferably 100-200°C, and in this example, it is 160°C. The pressure in the inner cavity is 1 torr, which is used to pretreat the surface of the substrate and reduce the oxygen content on the surface of the substrate.

[0063] ​​2. Put the substrate into the vacuum transfer chamber, then vacuumize, the pressure of the vacuum transfer chamber is preferably 0-2 torr, in this embodiment, 1 torr. Perform Ar circulation purge on the vacuum transfer chamber, the pressure of the vacuum transfer chamber during the circulation purge is 5-300 torr, the Ar flow is 2000 sccm, the number of circulation purges is preferably 10-20, in this embodiment, 10. After the circulation purge, the pressure of the vacuum transfer chamber is preferably 0-2 torr, in this embodiment, 1 torr. The purpose of the circulation purge is to purge the impurity gas on the surface of the substrate and the vacuum transfer chamber;

[0064] 3. Transfer the substrate from the vacuum transfer chamber to the inner chamber, the pressure difference between the vacuum transfer chamber and the inner chamber during the transfer is not more than 1 torr. After the transfer is completed, close the vacuum transfer chamber, i.e. close the outer chamber. Heat the substrate to the deposition temperature and keep the temperature stable;

[0065] 4. Perform Ar plasma pretreatment on the surface of the substrate to reduce the oxygen content and impurity particles on the surface of the substrate. During the pretreatment, turn on the plasma generator and Ar gas at the same time. The power of the plasma generator is 1000 W, the Ar flow is 300 sccm, the pretreatment time is 5-10 min, in this embodiment, 5 min. The pressure of the inner chamber is not limited. After the pretreatment, turn off the plasma generator and Ar gas;

[0066] 5. Perform CVD deposition for 90 s. During the CVD deposition, turn on the plasma generator and H2 at the same time. The carrier gas Ar of H2 is not changed during the CVD process, and the flow is 1000 sccm. The plasma generator is continuously turned on during the CVD process, and the power of the plasma generator is 1000 W. The flow of H2 is not changed during the CVD process, and is 5000 sccm. The flow of the carrier gas Ar of the CVD cobalt source is not changed during the CVD process, and is 500 sccm. The flow of the CVD cobalt source is not changed during the CVD process, and is 20 sccm. Except for the carrier gas Ar of the CVD cobalt source, the remaining balance carrier gas Ar is continuously turned on during the CVD process, and the flow of the balance carrier gas Ar is 500 sccm. The source temperature is not changed during the CVD process, and the source temperature is 45°C. The pressure of the inner chamber is not changed during the CVD process, and the pressure of the inner chamber is 10 torr;

[0067] 6. Perform annealing treatment on the substrate in the inner chamber after the deposition reaction. The temperature of the inner chamber is preferably 100-200°C, in this embodiment, 160°C. The annealing time is preferably 20-30 min, in this embodiment, 20 min;

[0068] 7. Transfer the substrate from the inner chamber to the vacuum transfer chamber and take it out.

[0069] The thickness (THK), sheet resistance, and resistivity of the cobalt film prepared on a 12-inch Si substrate using the method of this example were tested at nine points, and the results are shown in Table 1 below.

[0070] Table 1 Test results of cobalt film prepared on Si substrate using CVD method Note: In the table, (x, y) is the coordinate of the test point on the substrate, where the coordinate of the center of the substrate is (0, 0).

[0071] The thickness (THK), sheet resistance, and resistivity of the cobalt film prepared on a 12-inch Si / 50nm SiO2 composite substrate using the method of this example were tested at nine points, and the results are shown in Table 2 below.

[0072] Table 2 Test results of cobalt film prepared on Si / 50nm SiO2 composite substrate using CVD method Note: In the table, (x, y) is the coordinate of the test point on the substrate, where the coordinate of the center of the substrate is (0, 0).

[0073] The thickness (THK), sheet resistance, and resistivity of the cobalt film prepared on a 12-inch Si / 100nm SiO2 composite substrate using the method of this example were tested at nine points, and the results are shown in Table 3 below.

[0074] Table 3 Test results of cobalt film prepared on Si / 100nm SiO2 composite substrate using CVD method Note: In the table, (x, y) is the coordinate of the test point on the substrate, where the coordinate of the center of the substrate is (0, 0).

[0075] Example 2: Preparation of metal cobalt film by ALD method

[0076] The method for preparing a metal cobalt film using a deposition device without a spray assembly in the inner cavity of the deposition device includes the following steps:

[0077] 1. After heating the inner cavity to a deposition temperature, vacuumize the inner cavity, and the deposition temperature is preferably 100-200°C, and in this example, the deposition temperature is 160°C. The pressure in the inner cavity is 1 torr, which is used to pretreat the surface of the substrate and reduce the oxygen content on the surface of the substrate.

[0078] 2. Put the substrate into the vacuum transfer chamber, then vacuumize, the pressure of the vacuum transfer chamber is preferably 0-2 torr, in this embodiment, 1 torr, circulate Ar to purge the vacuum transfer chamber, the pressure of the vacuum transfer chamber during the circulation is 5-300 torr, the flow rate of Ar is 2000 sccm, the number of circulation is preferably 10-20, in this embodiment, 10, the pressure of the vacuum transfer chamber after the circulation is preferably 0-2 torr, in this embodiment, 1 torr, the purpose of the circulation is to purge the impurity gas on the surface of the substrate and the vacuum transfer chamber;

[0079] 3. Transfer the substrate from the vacuum transfer chamber to the inner chamber, the pressure difference between the vacuum transfer chamber and the inner chamber during the transfer is not more than 1 torr, after the transfer, close the vacuum transfer chamber, i.e. close the outer chamber, heat the substrate to the deposition temperature and keep the temperature stable;

[0080] 4. Perform Ar plasma pretreatment on the surface of the substrate to reduce the oxygen content and impurity particles on the surface of the substrate, turn on the plasma generator and Ar gas at the same time during the pretreatment, the power of the plasma generator is 1000 W, the flow rate of Ar is 300 sccm, the pretreatment time is 5-10 min, in this embodiment, 5 min, the pressure of the inner chamber is not limited, and after the pretreatment, turn off the plasma generator and Ar gas;

[0081] 5. Adopt ALD mode to deposit for 90 s, adopt ALD mode to deposit for 6 cycles, one cycle is 15 s (the pulse time of the ALD cobalt source is 1 s, the purge time of the carrier gas of the ALD cobalt source is 4 s, the pulse time of the ALD reaction gas is 3 s, and the purge time of the carrier gas of the ALD reaction gas is 7 s), a total of 90 s, the carrier gas Ar of H2 is not changed during the ALD process, and the flow rate is 1000 sccm, the power of the plasma generator is 1000 W, the flow rate of H2 is not changed during the ALD process, and is 5000 sccm, the flow rate of the carrier gas Ar of the ALD cobalt source is not changed during the ALD process, and is 500 sccm, the flow rate of the ALD cobalt source is 20 sccm, and is not changed during the ALD process; except the carrier gas Ar of the ALD cobalt source, the rest of the balance carrier gas Ar is continuously turned on during the ALD process, the flow rate of the balance carrier gas Ar is 500 sccm, the source temperature is not changed during the ALD process, and is 45°C, and the inner chamber pressure is not changed during the ALD process, and is 10 torr;

[0082] 6. Perform annealing treatment on the substrate in the inner chamber after the deposition reaction, the temperature of the inner chamber is preferably 100-200°C, in this embodiment, 160°C, and the annealing time is preferably 20-30 min, in this embodiment, 20 min;

[0083] 7. Transfer the substrate from the inner chamber to the vacuum transfer chamber to take out.

[0084] The thickness (THK), sheet resistance, and resistivity of the cobalt thin film prepared by the method of the present example using a 12-inch Si substrate were tested at nine points, and the results are shown in Table 4 below.

[0085] Table 4 Test results of cobalt thin film prepared by ALD method on Si substrate Note: In the table, (x, y) is the coordinate of the test point on the substrate, where the coordinate of the center of the substrate is (0, 0).

[0086] The thickness (THK), sheet resistance, and resistivity of the cobalt thin film prepared by the method of the present example using a 12-inch Si / 50nm SiO2 composite substrate were tested at nine points, and the results are shown in Table 5 below.

[0087] Table 5 Test results of cobalt thin film prepared by ALD method on Si / 50nm SiO2 composite substrate Note: In the table, (x, y) is the coordinate of the test point on the substrate, where the coordinate of the center of the substrate is (0, 0).

[0088] The thickness (THK), sheet resistance, and resistivity of the cobalt thin film prepared by the method of the present example using a 12-inch Si / 100nm SiO2 composite substrate were tested at nine points, and the results are shown in Table 6 below.

[0089] Table 6 Test results of cobalt thin film prepared by ALD method on Si / 100nm SiO2 composite substrate Note: In the table, (x, y) is the coordinate of the test point on the substrate, where the coordinate of the center of the substrate is (0, 0).

[0090] Example 3: Preparation of metal cobalt thin film by CVD combined with ALD method

[0091] 1. After heating the inner cavity to the deposition temperature, vacuumize, the deposition temperature is preferably 100-200°C, and in the present example, it is 160°C. The pressure in the inner cavity is 1 torr, which is used to pretreat the surface of the substrate and reduce the oxygen content on the surface of the substrate;

[0092] 2. Place the substrate in the vacuum transfer cavity, then vacuumize, the pressure in the vacuum transfer cavity is preferably 0-2 torr, and in the present example, it is 1 torr. Circulate Ar to sweep the vacuum transfer cavity, the pressure in the vacuum transfer cavity during the sweeping process is 5-300 torr, the Ar flow rate is 2000sccm, the number of sweeping cycles is preferably 10-20, and in the present example, it is 10. After the sweeping, the pressure in the vacuum transfer cavity is 0-2 torr, and in the present example, it is 1 torr. The purpose of the sweeping is to sweep the impurity gas on the surface of the substrate and the vacuum transfer cavity;

[0093] 3. Transfer the substrate from the vacuum transfer chamber to the inner chamber, the pressure difference between the vacuum transfer chamber and the inner chamber during the transfer is not more than 1 torr, and the vacuum transfer chamber is closed after the transfer, i.e. the outer chamber is closed; heat the substrate to the deposition temperature and keep the temperature stable;

[0094] 4. Perform Ar plasma pretreatment on the surface of the substrate to reduce the oxygen content and impurity particles on the surface of the substrate, the plasma generator and Ar gas are turned on at the same time during the pretreatment, the power of the plasma generator is 1000 W, the flow rate of the Ar gas is 300 sccm, the pretreatment time is 5-10 min, and in this example, the pretreatment time is 5 min, the inner chamber pressure is not limited, and the plasma generator and Ar gas are turned off after the pretreatment;

[0095] 5. Deposit for 90 s by using the CVD combined with ALD method, the flow rates of the carrier gas Ar of the CVD reaction gas and the carrier gas Ar of the ALD reaction gas are constant during the process, and are both 1000 sccm, the plasma generator is continuously turned on during the CVD and ALD processes, the power of the plasma generator is 1000 W, the flow rates of the CVD reaction gas H2 and the ALD reaction gas H2 are constant during the process, and are both 5000 sccm, the flow rates of the CVD and ALD cobalt sources are constant during the process, and are both 500 sccm, the flow rates of the CVD and ALD cobalt sources are constant during the process, and are both 20 sccm, the balance carrier gas Ar is continuously turned on during the CVD process, the flow rate of the balance carrier gas Ar except the carrier gas Ar of the CVD cobalt source and the carrier gas Ar of the ALD cobalt source is 500 sccm, the source temperature is constant during the CVD and ALD processes, and the source temperature is 45°C, the inner chamber pressure is constant during the CVD and ALD processes, and the inner chamber pressure is 10 torr, the CVD method is used to deposit at the same time as the ALD method is used to deposit for 6 cycles, and one cycle is 15 s (the ALD cobalt source pulse time is 1 s, the carrier gas purge time of the ALD cobalt source is 4 s, the ALD reaction gas pulse time is 3 s, and the carrier gas purge time of the ALD reaction gas is 7 s);

[0096] 6. Perform annealing treatment on the substrate in the inner chamber after the deposition reaction, the inner chamber temperature is preferably 100-200°C, and in this example, the inner chamber temperature is 160°C, and the annealing time is preferably 20-30 min, and in this example, the annealing time is 20 min;

[0097] 7. Transfer the substrate from the inner chamber to the vacuum transfer chamber and take out the substrate.

[0098] The thickness (THK), square resistance and resistivity of the cobalt thin film prepared by using the substrate of 12 inches in the example are shown in Table 7:

[0099] Table 7 Test results of the cobalt thin film prepared by using the CVD-ALD method on the Si substrate Note: In the table, (x, y) is the coordinate of the test point on the substrate, wherein the coordinate of the center of the substrate is (0, 0).

[0100] The thickness (THK), sheet resistance, and resistivity of the cobalt thin film prepared by the method of the present example using a 12-inch Si / 50nm SiO2 composite substrate are shown in Table 8.

[0101] Table 8 Test results of cobalt thin film prepared by CVD-ALD method on Si / 50nm SiO2 composite substrate Note: In the table, (x, y) is the coordinate of the test point on the substrate, wherein the coordinate of the center of the substrate is (0, 0).

[0102] The thickness (THK), sheet resistance, and resistivity of the cobalt thin film prepared by the method of the present example using a 12-inch Si / 100nm SiO2 composite substrate are shown in Table 9.

[0103] Table 9 Test results of cobalt thin film prepared by CVD-ALD method on Si / 100nm SiO2 composite substrate Note: In the table, (x, y) is the coordinate of the test point on the substrate, wherein the coordinate of the center of the substrate is (0, 0).

[0104] Example 4: Preparation of cobalt thin film by CVD combined with ALD method after setting spray assembly in inner cavity

[0105] In the present example, the method for preparing a cobalt thin film using a deposition device with a spray assembly in the inner cavity is the same as that of Example 3, and the remaining experimental conditions are the same. The difference lies in that a spray assembly is set in the inner cavity of the deposition device, and the output ends of the six balanced carrier gas pipelines are connected to the opening of one end of the ventilation pipeline 600, and optionally two oppositely arranged balanced carrier gas pipelines are connected to the cobalt source as the carrier gas pipeline of the CVD cobalt source and the carrier gas pipeline of the ALD cobalt source.

[0106] The thickness (THK), sheet resistance, and resistivity of the cobalt thin film prepared by the method of the present example using a 12-inch Si substrate are shown in Table 10.

[0107] Table 10 Test results of cobalt thin film prepared by spray assembly+CVD-ALD method on Si substrate Note: In the table, (x, y) is the coordinate of the test point on the substrate, wherein the coordinate of the center of the substrate is (0, 0).

[0108] Using the method of this embodiment, the thickness (THK), sheet resistance, and resistivity nine-point test results of the cobalt thin film prepared using a 12-inch Si / 50nm SiO2 composite substrate are shown in Table 11 below:

[0109] Table 11 Cobalt thin film test results of Si / 50nm SiO2 composite substrate prepared by spray assembly + CVD-ALD method Note: In the table, (x, y) is the coordinate of the test point on the substrate, wherein the coordinate of the center of the substrate is (0, 0).

[0110] Using the method of this embodiment, the thickness (THK), sheet resistance, and resistivity nine-point test results of the cobalt thin film prepared using a 12-inch Si / 100nm SiO2 composite substrate are shown in Table 12 below:

[0111] Table 12 Cobalt thin film test results of Si / 100nm SiO2 composite substrate prepared by spray assembly + CVD-ALD method Note: In the table, (x, y) is the coordinate of the test point on the substrate, wherein the coordinate of the center of the substrate is (0, 0).

[0112] The test results of the different cobalt thin films obtained in Examples 1-4 are analyzed as follows:

[0113] (1) After calculating the uniformity of the thickness of the nine test points of the cobalt thin films prepared in Example 1 and Example 3, respectively, as shown in Table 13, the cobalt thin film prepared by the CVD combined with ALD method has a uniformity of the cobalt thin film prepared by the CVD method alone, which is reduced by 50%-62% for the three different substrates, indicating that the preparation method of CVD combined with ALD can effectively improve the uniformity of the cobalt thin film.

[0114] Table 13 Cobalt thin film 1-sigma (%) - uniformity comparison

[0115] (2) As shown in Table 14, the average resistivity of the nine test points of the cobalt thin films prepared in Example 1 and Example 3 is compared, respectively, and the cobalt thin film prepared by the CVD combined with ALD method can significantly reduce the resistivity of the prepared cobalt thin film compared with the CVD preparation method alone, so that the performance of the cobalt thin film is better.

[0116] Table 14 Cobalt thin film resistivity (μΩ·cm) comparison

[0117] (3) The growth rate of the cobalt thin film prepared by the CVD-ALD method with the spray assembly was calculated according to the growth time and the average film thickness of the cobalt thin film prepared in Example 3, and was compared with the growth rate of the cobalt thin film prepared by the CVD-ALD method without the spray assembly, as shown in Table 15. The growth rate of the cobalt thin film prepared by the CVD-ALD method with the spray assembly was increased by about 25 times compared with the growth rate of the cobalt thin film prepared by the ALD method, which was very significant.

[0118] Table 15 Growth rate of cobalt thin film Comparison

[0119] (4) The uniformity of the cobalt thin film prepared in Example 3 was calculated according to the thickness of the nine test points, and the uniformity of the cobalt thin film prepared in Example 4 was calculated according to the thickness of the nine test points, as shown in Table 16. The uniformity of the cobalt thin film prepared by the CVD-ALD method with the spray assembly was further reduced by more than 50% compared with the uniformity of the cobalt thin film prepared by the CVD-ALD method without the spray assembly, which indicated that the use of the spray assembly could effectively improve the uniformity of the cobalt thin film.

[0120] Table 16 Comparison of 1-sigma (%) uniformity of CVD-ALD method with and without spray assembly

[0121] (5) The average resistivity of the cobalt thin film prepared in Example 3 was compared with the average resistivity of the cobalt thin film prepared in Example 4, as shown in Table 17. The resistivity of the cobalt thin film prepared by the CVD-ALD method with the spray assembly was obviously reduced compared with the resistivity of the cobalt thin film prepared by the CVD-ALD method without the spray assembly, which indicated that the use of the spray assembly could also effectively reduce the resistivity of the cobalt thin film.

[0122] Table 17 Comparison of resistivity (μΩ·cm) of CVD-ALD method with and without spray assembly

[0123] The above examples of the present application and the related performance test data of the cobalt thin film prepared in the examples show that, by combining the CVD method and the ALD method to prepare the cobalt thin film, the growth efficiency of the cobalt thin film prepared by the CVD-ALD method is higher than the growth efficiency of the cobalt thin film prepared by the ALD method, and the growth uniformity (film thickness) of the cobalt thin film prepared by the CVD-ALD method is better than the growth uniformity of the cobalt thin film prepared by the CVD method and the resistivity of the cobalt thin film is lower. At the same time, the present application provides a spray assembly of a deposition device, which compresses the reduction reaction space of H2 and CCTBA to a local area of the first panel and the second panel, reduces the influence of the non-uniformity of the reaction area and the gas phase diffusion effect on the deposition uniformity, and further improves the film thickness uniformity of the cobalt thin film and reduces the resistivity of the cobalt thin film on the basis of the CVD-ALD method.

Claims

1. A method for preparing a cobalt thin film, wherein, include: The method is applied in the inner cavity of a deposition equipment, in which a substrate is placed. The method employs simultaneous CVD and ALD to react the cobalt source and the reactive gas, thereby depositing a thin film of metallic cobalt on the substrate.

2. The method for preparing a cobalt thin film according to claim 1, wherein, The deposition equipment is provided with two or more balance carrier gas pipelines leading into the inner cavity, one or more CVD reaction gas and its carrier gas pipelines, and one or more ALD reaction gas and its carrier gas pipelines leading into the inner cavity via a plasma generator. When the balance carrier gas pipeline is connected to the cobalt source, it serves as either the CVD cobalt source and its carrier gas pipeline or the ALD cobalt source and its carrier gas pipeline. In this case, the balance carrier gas serves as the carrier gas for the CVD cobalt source or the ALD cobalt source. In the method described above, the CVD reactant gas and its carrier gas pipeline, the ALD reactant gas and its carrier gas pipeline, the plasma generator, the CVD cobalt source and its carrier gas pipeline, the ALD cobalt source and its carrier gas pipeline, and all other balanced carrier gas pipelines except for the CVD cobalt source and its carrier gas pipeline and the ALD cobalt source and its carrier gas pipeline are kept in an open state. At the same time, the ALD cobalt source and its carrier gas pipeline and the ALD reactant gas and its carrier gas pipeline are turned on or off as needed for the ALD cycle. The ALD cycle includes: ALD cobalt source pulse, ALD cobalt source carrier gas purging, ALD reactant gas pulse, and ALD reactant gas carrier gas purging.

3. The method for preparing a cobalt thin film according to claim 2, wherein, The deposition equipment is also equipped with an inert gas pipeline that enters the inner cavity via a plasma generator. The output port diameters of the inert gas pipeline, the CVD reaction gas and its carrier gas pipeline, the ALD reaction gas and its carrier gas pipeline, the CVD cobalt source and its carrier gas pipeline, the ALD cobalt source and its carrier gas pipeline, and the remaining balance carrier gas pipelines are all the same. Under these conditions, the gas flow rates of the carrier gas of the CVD cobalt source and the ALD cobalt source, and the remaining balance carrier gases are equal. The flow rates of the CVD cobalt source and the ALD cobalt source are equal. The flow rates of the carrier gas of the CVD reaction gas and the ALD reaction gas are equal.

4. The method for preparing a cobalt thin film according to claim 3, wherein, The inert gas pipeline is used for plasma pretreatment of the substrate surface.

5. The method for preparing a cobalt thin film according to claim 1, wherein, The preparation method further includes annealing the cobalt thin film.

6. The method for preparing a cobalt thin film according to claim 1, wherein, The CVD process and the ALD process start and stop simultaneously, and the number of ALD cycles to complete ALD deposition during CVD is no less than 1.

7. The method for preparing a cobalt thin film according to claim 3, wherein, The CVD cobalt source and ALD cobalt source are CCTBA, the CVD reaction gas and ALD reaction gas are H2, and the carrier gas, other equilibrium carrier gas and inert gas of the CVD reaction gas and ALD reaction gas are all Ar.

8. The method for preparing a cobalt thin film according to claim 7, wherein, During the preparation of the cobalt thin film, the deposition temperature of the inner cavity is 100℃-200℃, and the cavity pressure is 8 torr-12 torr during CVD and ALD processes. The flow rates of the CVD reaction gas and the ALD reaction gas H2 are 5000 sccm, the flow rates of the carrier gas Ar for the CVD reaction gas and the ALD reaction gas are 1000 sccm, the flow rates of the CVD cobalt source and the ALD cobalt source CCTBA are 0-30 sccm, the flow rates of the carrier gas for the CVD cobalt source and the ALD cobalt source, and the flow rates of the remaining equilibrium carrier gas Ar are 500 sccm, the plasma generator power is 1000W, and the temperature of the cobalt source CCTBA is 45℃.

9. The method for preparing a cobalt thin film according to claim 8, wherein, The time for one cycle of the ALD is 15s, including: an ALD cobalt source pulse time of 1s, i.e., an ALD cobalt source turn-on time of 1s; an ALD cobalt source carrier gas purging time of 4s, i.e., an ALD cobalt source turn-off time of 4s; an ALD reaction gas pulse time of 3s, i.e., an ALD reaction gas turn-on time of 3s; and an ALD reaction gas carrier gas purging time of 7s, i.e., an ALD reaction gas turn-off time of 7s.

10. The method for preparing a cobalt thin film according to claim 2, wherein, The deposition apparatus has a detachable spray assembly inside its cavity. The spray assembly includes a columnar sidewall (500) and a first panel (100) and a second panel (200) connected to both ends of the columnar sidewall (500). The columnar sidewall (500) has a thickness, and two or more ventilation pipes (600) are dispersedly arranged inside the columnar sidewall (500). One end of each ventilation pipe (600) is located near the second panel (200) of the columnar sidewall (500). A radial cobalt source delivery channel (300) is provided near the first panel (100) of the columnar sidewall (500). The cobalt source delivery channel (300) is used to introduce a CVD cobalt source and its carrier gas, an ALD cobalt source and its carrier gas, and other balancing carrier gases. The first panel (100) is divided into multiple sectors by the cobalt source delivery channel (300). The fan-shaped region (110) includes multiple arrayed through holes (111); the radiation center of the cobalt source delivery channel (300) is set to face the gas mixing region (400) of the second panel, and one end of the cobalt source delivery channel (300) is connected to the gas mixing region (400); the other end of the cobalt source delivery channel (300) is connected to the other end of the ventilation pipe (600); the second panel (200) includes multiple spray holes (210) arranged in the circumferential and radial directions, and a substrate support is installed at the end of the second panel (200) away from the first panel (100); when the spray assembly is installed in the inner cavity, the output ends of the CVD cobalt source and its carrier gas pipe, the ALD cobalt source and its carrier gas pipe, and the remaining balanced carrier gas pipes are connected to the opening of one end of the ventilation pipe (600); In the method for preparing the cobalt metal thin film, the CVD reaction gas and its carrier gas and the ALD reaction gas and its carrier gas flow through the through hole (111) to the region between the first panel (100) and the second panel (200). After the CVD source and its carrier gas and the ALD cobalt source and its carrier gas are gathered in the gas mixing region (400), they diffuse and mix with the CVD reaction gas and its carrier gas and the ALD reaction gas and its carrier gas in the region between the first panel (100) and the second panel (200), and then flow to the substrate through the spray hole (210).

11. The method for preparing a cobalt thin film according to claim 10, wherein, The diameter of the spray hole (210) is smaller than the diameter of the through hole (111).

12. The cobalt metal thin film prepared by the method of any one of claims 1 to 11.

13. A composite film comprising the cobalt metal thin film of claim 12, wherein, The composite thin film includes a composite substrate and a thin film layer, wherein the thin film layer is a cobalt thin film; the composite substrate includes a substrate layer and an isolation layer attached to the substrate layer; a thin film layer is formed by depositing a film on the isolation layer.

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