Preparation method of tungsten carbide film

Abstract

The invention discloses a preparation method of a tungsten carbide film, which can be used in the field of semiconductors, and the preparation method of the tungsten carbide film comprises the following steps: firstly, introducing inert gas into an auxiliary ion source to pre-clean a sample, and introducing inert gas into a sputtering ion source to pre-clean the surface of a target material; then, inert gas is introduced into the sputtering ion source, and a sputtering ion beam is formed; introducing reaction gas into the auxiliary ion source to form a reaction ion beam; then, the sputtering ion beam bombards the surface of the target material, and sputtering particles are generated; and finally, carrying out chemical reaction on the sputtering particles and the reaction ion beam, and depositing on the surface of the sample to form the tungsten carbide film. Therefore, the tungsten carbide thin film is prepared through the ion beam deposition method, the sample and the target material are pre-cleaned before the tungsten carbide thin film is deposited, dirt and attachments such as a natural oxide layer on the surfaces of the sample and the target material are pre-cleaned, impurity pollution is reduced, and the tungsten carbide thin film with high adhesion and high quality can be prepared.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a method for preparing tungsten carbide thin films. Background Technology

[0002] With the rapid development of integrated circuit technology, the size of semiconductor devices is constantly shrinking. In order to ensure the accuracy of semiconductor device structure, the requirements for manufacturing process are also becoming increasingly higher.

[0003] When etching the fine structures of small-sized semiconductor devices, the limitations of photolithography are becoming increasingly apparent, leading to the widespread use of hard masks. Tungsten carbide (TCC) thin films, possessing both high etching selectivity and adjustable low stress during high aspect ratio etching processes, have become an ideal choice for hard mask materials. Currently, TCC thin films are typically prepared using chemical vapor deposition (CVD) at high temperatures. However, TCC thin films prepared by this method exhibit poor adhesion and are susceptible to impurity contamination, resulting in poor quality stability and unstable etching rates. This ultimately affects the stability of semiconductor devices fabricated using TCC as a hard mask.

[0004] Therefore, how to prepare high-quality tungsten carbide thin films has become a problem that needs to be solved. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a method for preparing tungsten carbide thin films, which can produce high-quality tungsten carbide thin films.

[0006] The embodiments of this application disclose the following technical solutions:

[0007] In a first aspect, embodiments of this application provide a method for preparing a tungsten carbide thin film, the method comprising:

[0008] An inert gas is introduced into the auxiliary ion source to pre-clean the sample, and an inert gas is introduced into the sputtering ion source to pre-clean the target surface; the target is a tungsten target.

[0009] An inert gas is introduced into the sputtering ion source to form a sputtering ion beam; a reactive gas is introduced into the auxiliary ion source to form a reactive ion beam; the reactive gas includes a carbon-based gas.

[0010] The sputtered ion beam bombards the target surface, generating sputtered particles;

[0011] The sputtered particles react chemically with the reactive ion beam to deposit a tungsten carbide thin film on the sample surface.

[0012] Optionally, the sputtered particles chemically react with the reactive ion beam to deposit a tungsten carbide thin film on the sample surface, comprising:

[0013] The sputtered particles react chemically with the reactive ion beam to deposit a tungsten carbide film on the sample surface at a preset deposition rate; the preset deposition rate is selected from 1.5 nm / min to 10 nm / min.

[0014] Optionally, before introducing an inert gas into the auxiliary ion source to pre-clean the sample, and before introducing an inert gas into the sputtering ion source to pre-clean the target surface, the method further includes:

[0015] Adjust the ion beam deposition angle and the sample revolution angle; the ion beam deposition angle is the angle between the sample and the normal direction of the auxiliary ion source; the sample revolution angle is driven by electrodes and is selected from the range of -90° to 60°.

[0016] Optionally, before the sputtered particles chemically react with the reactive ion beam to deposit a tungsten carbide thin film on the sample surface, the method further includes:

[0017] The sample is controlled to rotate about its central axis.

[0018] Optionally, before introducing an inert gas into the sputtering ion source to form a sputtered ion beam, the method further includes:

[0019] The energy and energy density of the reactive ion beam are adjusted based on the target roughness.

[0020] Optionally, before introducing an inert gas into the sputtering ion source to form a sputtered ion beam, and before introducing a reactive gas into the auxiliary ion source to form a reactive ion beam, the method further includes:

[0021] The reaction temperature is controlled by a cooling system and a heating stage; the reaction temperature is selected between 5°C and 350°C.

[0022] Optionally, the thickness of the tungsten carbide film is in the range of 10 nm to 500 nm.

[0023] Optionally, the carbon-based gas is methane, propane, or acetylene.

[0024] Optionally, the reaction gas includes a carbon-based gas and an inert gas, wherein the flow rate ratio of the carbon-based gas to the inert gas is selected from 0.5 to 2.

[0025] Optionally, the spot size of the sputtered ion beam is smaller than the size of the target material.

[0026] Optionally, the energy of the reactive ion beam is less than or equal to 200 eV.

[0027] Secondly, embodiments of this application provide a method for manufacturing a semiconductor device, wherein a tungsten carbide thin film is used as a hard mask during the manufacturing process of the device; the tungsten carbide thin film is prepared by the tungsten carbide thin film preparation method described in any of the embodiments of the first aspect above.

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

[0029] This application provides a method for preparing a tungsten carbide thin film. In this method, firstly, an inert gas is introduced into an auxiliary ion source to pre-clean the sample, and an inert gas is introduced into a sputtering ion source to pre-clean the target surface; the target is a tungsten target. Then, an inert gas is introduced into the sputtering ion source to form a sputtered ion beam; a reactive gas is introduced into the auxiliary ion source to form a reactive ion beam; the reactive gas includes a carbon-based gas. Next, the sputtered ion beam bombards the target surface, generating sputtered particles. Finally, the sputtered particles react chemically with the reactive ion beam, depositing a tungsten carbide thin film on the sample surface. Therefore, by preparing a tungsten carbide thin film using ion beam deposition, the sample and target can be pre-cleaned before deposition, removing dirt and natural oxide layers from the sample and target surfaces, reducing impurity contamination, resulting in a more stable quality of the deposited tungsten carbide thin film, and enabling the production of tungsten carbide thin films with high adhesion and high quality. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A flowchart illustrating a method for preparing a tungsten carbide thin film according to an embodiment of this application;

[0032] Figure 2 A schematic diagram illustrating a tungsten carbide deposition process provided in an embodiment of this application;

[0033] Figure 3 This is a flowchart illustrating another method for preparing a tungsten carbide thin film provided in an embodiment of this application. Detailed Implementation

[0034] The method for preparing a tungsten carbide thin film provided in this application can be used in the semiconductor field. The above is only an example and does not limit the application field of the method for preparing a tungsten carbide thin film provided in this application.

[0035] The terms "first," "second," "third," and "fourth," etc., used in this application specification, claims, and drawings are used to distinguish different objects, not to limit a specific order.

[0036] In the embodiments of this application, the terms "as an example" or "for example" are used to indicate that they are examples, illustrations, or explanations. Any embodiment or design that is described as "as an example" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Specifically, the use of terms such as "as an example" or "for example" is intended to present the relevant concepts in a specific manner.

[0037] The terminology used in the implementation section of this application is for the purpose of explaining specific embodiments of this application only, and is not intended to limit this application.

[0038] As mentioned earlier, with integrated circuits continuously advancing towards advanced technology nodes below 7 nanometers, producing structures with submicron and smaller feature sizes has become one of the key technological challenges for next-generation very large-scale integrated circuits (VLSI) and extremely large-scale integrated circuits (ULSI). Currently, although photolithography is relatively mature, when etching the fine structures of small-sized semiconductor devices, if photoresist is used as a mask, its thickness needs to be reduced as the pattern size shrinks to control pattern resolution. However, under chemical etching, such thin photoresist is difficult to effectively protect the underlying sample during pattern transfer, and the limitations of photolithography are becoming increasingly apparent. To make the mask layer more resistant to chemical etchants, a hard mask layer, such as silicon oxide, titanium nitride, or carbon film, is typically added as an intermediate layer between the photoresist and the underlying sample. This layer works with the photoresist to form a mask pattern, which is then removed by etching after pattern transfer.

[0039] Therefore, compared to the sample material, the hard mask needs to have a high etching selectivity to avoid failures in pattern transfer and dimensional control. Because the pattern size and spacing are extremely small, typically only tens of nanometers, the requirements for the precision and uniformity of photolithography and etching are extremely high. The hard mask needs to have a high etching selectivity and low line edge roughness to ensure the quality and consistency of the pattern. Simultaneously, the pattern transfer and alignment during the process are very complex, requiring multiple photolithography and etching processes, thus placing extremely high demands on the stability and reliability of the hard mask. Furthermore, the hard mask also needs to have high heat resistance and corrosion resistance, maintaining its shape and performance in high-temperature and strong acid / alkali environments.

[0040] As the size of integrated circuit components shrinks to the nanometer scale, hard mask layers also need to possess properties such as low dielectric constant and low stress. Currently, titanium nitride has become one of the most commonly used hard mask materials due to its high selectivity compared to low-k dielectrics in etching processes. However, titanium nitride masks exhibit significant residual stress after etching, which can cause linewidth creep shrinkage, leading to line bending and pattern collapse. Therefore, it is necessary to select a thin film that possesses both high selectivity during etching and adjustable low stress.

[0041] Tungsten carbide (TCC) thin films, possessing both high etch selectivity and adjustable low stress during high aspect ratio etching processes, have become an ideal choice for hard mask materials. Currently, TCC thin films are typically prepared using chemical vapor deposition (CVD) at high temperatures. However, TCC thin films prepared by this method exhibit poor adhesion and are susceptible to impurity contamination, resulting in poor quality stability and unstable etching rates. This ultimately affects the stability of semiconductor devices fabricated using TCC as a hard mask.

[0042] In view of this, embodiments of this application provide a method for preparing a tungsten carbide thin film. In this method, firstly, an inert gas is introduced into an auxiliary ion source to pre-clean the sample, and an inert gas is introduced into a sputtering ion source to pre-clean the target surface; the target is a tungsten target. Then, an inert gas is introduced into the sputtering ion source to form a sputtered ion beam; a reactive gas is introduced into the auxiliary ion source to form a reactive ion beam; the reactive gas includes a carbon-based gas. Next, the sputtered ion beam bombards the target surface, generating sputtered particles. Finally, the sputtered particles chemically react with the reactive ion beam, depositing a tungsten carbide thin film on the sample surface. Thus, by preparing a tungsten carbide thin film using ion beam deposition, the sample and target can be pre-cleaned before deposition, removing dirt and natural oxide layers from the sample and target surfaces, reducing impurity contamination, resulting in a more stable quality of the deposited tungsten carbide thin film, and enabling the production of tungsten carbide thin films with high adhesion and high quality.

[0043] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0044] See Figure 1 The figure is a flowchart of a method for preparing a tungsten carbide thin film according to an embodiment of this application. The method includes:

[0045] S101: Inert gas is introduced into the auxiliary ion source to pre-clean the sample, and inert gas is introduced into the sputtering ion source to pre-clean the target surface.

[0046] Specifically, the target material is a tungsten target material. In the embodiments of this application, inert gases, such as one or more mixed gases selected from Ar, He, Ne, Kr, and Xe, can be introduced simultaneously or sequentially into the auxiliary ion source and the sputtering ion source to remove dirt or natural oxide layers and other deposits from the sample and target surfaces, thereby pre-cleaning the sample and target surfaces and providing clean, uncontaminated samples and targets for subsequent tungsten carbide deposition. This improves the quality of the deposited tungsten carbide film and increases its adhesion.

[0047] Optionally, the samples in the embodiments of this application may include, but are not limited to, semiconductor structures formed on silicon substrates, sapphire substrates, or quartz substrates.

[0048] S102: Inert gas is introduced into the sputtering ion source to form a sputtering ion beam; reactive gas is introduced into the auxiliary ion source to form a reactive ion beam.

[0049] Specifically, under the action of a sputtering ion source, inert gas molecules are excited to release electrons, forming charged plasma. The plasma is then filtered and focused by a grid, ultimately forming a sputtered ion beam with extremely high energy and precision. An auxiliary ion source applies an electric or magnetic field to ionize reactive gas molecules, forming plasma. These ions are then focused under the action of an electric field to form a reactive ion beam.

[0050] Optionally, the inert gas introduced into the sputtering ion source is a gas that does not react with the sample and target material and only has a physical sputtering effect. Specifically, it can be one or a combination of He, Ne, Ar, Kr, and Xe. The reactive gas introduced into the auxiliary ion source includes carbon-based gases, specifically including one or a combination of methane (CH4), propane (C3H8), and acetylene (C2H2).

[0051] S103: Sputtered ion beams bombard the surface of the target material to generate sputtered particles.

[0052] Specifically, the high-speed impact of the sputtered ion beam on the target surface allows the target atoms or molecules to gain enough energy to detach from the surface, forming sputtered particles containing tungsten.

[0053] S104: Sputtered particles react chemically with the reactive ion beam to deposit a tungsten carbide thin film on the sample surface.

[0054] Specifically, sputtered particles containing tungsten collide with reactive ion beams containing carbon, resulting in energy exchange and charge transfer, and a chemical reaction that gradually forms a thin film of tungsten carbide on the sample surface.

[0055] Therefore, this application provides a method for preparing a tungsten carbide thin film. In this method, firstly, an inert gas is introduced into an auxiliary ion source to pre-clean the sample, and an inert gas is introduced into a sputtering ion source to pre-clean the target surface; the target is a tungsten target. Then, an inert gas is introduced into the sputtering ion source to form a sputtered ion beam; a reactive gas is introduced into the auxiliary ion source to form a reactive ion beam; the reactive gas includes a carbon-based gas. Next, the sputtered ion beam bombards the target surface, generating sputtered particles. Finally, the sputtered particles react chemically with the reactive ion beam, depositing a tungsten carbide thin film on the sample surface. Because tungsten carbide thin films are prepared by ion beam deposition, the sample and target can be pre-cleaned before deposition, removing dirt and natural oxide layers from the sample and target surfaces, reducing impurity contamination, resulting in a more stable quality of the deposited tungsten carbide thin film, and enabling the production of tungsten carbide thin films with high adhesion and high quality.

[0056] See Figure 2 The figure is a schematic diagram of a tungsten carbide deposition process provided in an embodiment of this application. The dashed line represents the ion beam; the sputtering ion source and the assist ion source are both radio frequency inductively coupled plasma ion sources (RFICP sources).

[0057] In the deposition of tungsten carbide, an inert gas, argon, is introduced into the sputtering ion source. Under the action of the sputtering ion source, the inert gas molecules are ionized to form a sputtered ion beam. A mixture of methane and acetylene (CH4, C2H2 gas inlet) is introduced into the auxiliary ion source. Under the action of the auxiliary ion source, the methane and acetylene mixture is ionized to form a reactive ion beam. The sputtered ion beam bombards the tungsten target, generating sputtered particles. The sputtered particles react chemically with the reactive ion beam, depositing a tungsten carbide thin film on the sample surface. The spot size of the sputtered ion beam can be smaller than the size of the tungsten target, allowing the sputtered ion beam to be focused on the center of the tungsten target, ensuring the purity of the sputtered particles and further reducing the impurity content in the resulting tungsten carbide thin film.

[0058] See Figure 3 The figure is a flowchart of another method for preparing a tungsten carbide thin film according to an embodiment of this application. The method includes:

[0059] S301: Controls the sample to rotate around its central axis.

[0060] Specifically, before deposition begins, the sample can be controlled to rotate around its central axis, and this rotation can be maintained throughout the ion beam deposition process, thereby improving the uniformity of the deposited tungsten carbide film. Optionally, the rotational speed of the sample can be between 1 r / min and 200 r / min. As an example, before deposition begins, the rotational speed of the sample can be gradually increased to a set value; during deposition, the sample can maintain a uniform rotation speed.

[0061] Optionally, the uniformity of the deposited tungsten carbide film can be controlled by adjusting the ion beam deposition angle and the sample's revolution angle, where the ion beam deposition angle is the angle between the sample and the normal direction of the auxiliary ion source. For example, the sample's revolution angle can be adjusted within the range of -90° to 60° by electrode driving.

[0062] S302: The reaction temperature is controlled by a cooling system and a hot plate.

[0063] As an example, the cooling system can be a water-cooling system or an air-cooling system, which can efficiently remove the heat generated during the deposition process and maintain the temperature stability of the entire system. The hot stage typically integrates heating and temperature sensing elements, which can heat or cool the substrate according to a preset temperature profile, providing high-precision temperature control. In this embodiment, a dual temperature control is achieved using a cooling system and a hot stage. The hot stage can heat and maintain the required temperature level, while the cooling system can remove excess heat when needed. This allows for fine temperature control, reduces temperature fluctuations during the deposition process, and keeps the reaction temperature stable throughout the ion beam deposition process.

[0064] In this embodiment, the tungsten carbide deposition process can be carried out at different temperatures. The reaction temperature can be selected from 5℃ to 350℃. By using a cooling system and a hot stage for dual temperature control, the reaction temperature can be controlled within a relatively stable range, for example, 40℃±2℃, thereby improving the repeatability of tungsten carbide films prepared in different batches.

[0065] S303: Inert gas is introduced into the auxiliary ion source to pre-clean the sample, and inert gas is introduced into the sputtering ion source to pre-clean the target surface.

[0066] Specifically, inert gases, such as one or more mixed gases of Ar, He, Ne, Kr, and Xe, can be introduced into the auxiliary ion source and sputtering ion source simultaneously or sequentially to remove dirt or natural oxide layers from the sample and target surfaces, thereby pre-cleaning the sample and target surfaces and providing clean, uncontaminated samples and targets for subsequent tungsten carbide deposition. This improves the quality of the deposited tungsten carbide film and increases its adhesion.

[0067] As an example, the target material is a tungsten target material with a purity greater than 99.99%; the sample may include, but is not limited to, a semiconductor structure formed on a silicon substrate, sapphire substrate or quartz substrate.

[0068] S304: Inert gas is introduced into the sputtering ion source to form a sputtering ion beam; reactive gas is introduced into the auxiliary ion source to form a reactive ion beam.

[0069] Specifically, under the action of a sputtering ion source, inert gas molecules are excited to release electrons, forming charged plasma. This plasma is then filtered and focused by a grid, ultimately forming a sputtered ion beam with extremely high energy and precision. The grid corresponding to the sputtering ion source is arc-shaped to focus the sputtered ion beam onto the surface of the tungsten target. The radius of the arc is within the range of not less than 300 mm and not more than 800 mm. After the beam is pulled by the grid, the spot size of the sputtered ion beam is smaller than the size of the tungsten target, thus ensuring that the sputtered ion beam can be focused onto the center of the tungsten target, improving the purity of the sputtered particles, and further reducing the impurity content in the subsequently produced tungsten carbide thin film.

[0070] Optionally, the inert gas introduced into the sputtering ion source can be a mixture of one or more of Ar, He, Ne, Kr, and Xe; the reactive gas introduced into the auxiliary ion source includes carbon-based gases, specifically a mixture of one or more of methane (CH4), propane (C3H8), and acetylene (C2H2), to provide the carbon element required during the tungsten carbide thin film deposition process.

[0071] Optionally, the reaction gas introduced into the auxiliary ion source can also be a mixture of carbon-based gas and inert gas. By adjusting the ratio of carbon-based gas to inert gas, the etching resistance of the deposited tungsten carbide film can be adjusted. For example, the flow rate ratio of carbon-based gas to inert gas can be selected from 0.5 to 2, thereby making the deposited tungsten carbide film more resistant to etching.

[0072] Optionally, the roughness of the deposited tungsten carbide film can be adjusted based on the desired target roughness by regulating the energy, current density, and ion beam deposition angle of the reactive ion beam, where the ion beam deposition angle is the angle between the sample and the normal direction of the auxiliary ion source. Preferably, the energy of the reactive ion beam is less than or equal to 200 eV, the current density is in the range of 0.1 A to 0.5 A, and the ion beam deposition angle is greater than 15°. This results in lower reactive ion beam energy, less sputtering effect during deposition, and avoids damage to the deposited film during the deposition process.

[0073] As an example, the energy of the sputtered ion beam can be selected from the range of 400 eV to 1000 eV. Thus, the sputtered ion beam has high energy and can more easily generate sputtered particles by bombarding the surface of the target material.

[0074] S305: Sputtered ion beams bombard the surface of the target material to generate sputtered particles.

[0075] S306: Sputtered particles react chemically with the reactive ion beam to deposit a tungsten carbide film on the sample surface at a preset deposition rate.

[0076] Specifically, sputtered particles containing tungsten collide with reactive ion beams containing carbon, resulting in energy exchange and charge transfer, and a chemical reaction that gradually forms a thin film of tungsten carbide on the sample surface.

[0077] Optionally, the preset deposition rate of the tungsten carbide thin film is selected from 1.5 nm / min to 10 nm / min.

[0078] S307: Real-time monitoring of the thickness of the tungsten carbide film deposited on the sample surface via a crystal oscillator.

[0079] Specifically, during ion beam deposition, the thickness of the tungsten carbide film deposited on the sample surface is monitored in real time using a crystal oscillator. Deposition can be stopped when the tungsten carbide film thickness reaches a preset thickness, thereby ensuring good stability and repeatability of different batches of tungsten carbide films prepared by the method provided in this application. Optionally, the thickness of the tungsten carbide film is in the range of 10 nm to 500 nm.

[0080] In addition, this application also provides a method for manufacturing a semiconductor device, wherein a tungsten carbide thin film is used as a hard mask during the manufacturing process; the tungsten carbide thin film is prepared by the tungsten carbide thin film preparation method described in any of the above embodiments.

[0081] The following will further describe, with examples, the process of preparing tungsten carbide thin films using the methods provided in the embodiments of this application.

[0082] Example 1: The energy of the sputtered ion beam was set to 1000 eV and the current density was 0.4 A; the energy of the ion beam generated by the auxiliary ion source was set to 200 eV; the reaction temperature was controlled at 25℃; and the sample rotation speed was 20 r / min to 100 r / min.

[0083] First, inert gas argon (Ar) is introduced into the auxiliary ion source to generate a neutral ion beam, which pre-cleans the sample surface, removing oxides with a relatively high energy angle. For example, the angle between the sample and the normal direction of the auxiliary ion source can be between 45° and 75°. Then, inert gas argon (Ar) is introduced into the sputtering ion source to generate a neutral ion beam that bombards the tungsten target, pre-cleaning the tungsten target to remove impurities from its surface. Next, with the angle between the sample and the normal direction of the auxiliary ion source at a fixed angle greater than 15°, inert gas argon (Ar) is introduced into the sputtering ion source to generate a sputtering ion beam. A reactive gas including methane (CH4) is introduced into the auxiliary ion source to form a reactive ion beam. Subsequently, the sputtering ion beam bombards the surface of the tungsten target, generating sputtered particles. Finally, the tungsten particles sputtered from the target are deposited on the pre-cleaned sample surface under the reaction and impetus of the reactive ion beam, forming a tungsten carbide thin film of 20 nm to 150 nm. Optionally, after pre-cleaning the sample surface, the angle between the sample and the normal direction of the auxiliary ion source can be adjusted to a preset value.

[0084] Example 2: The energy of the sputtered ion beam was set to 700 eV and the current density to 0.4 A; the energy of the ion beam generated by the auxiliary ion source was set to 200 eV; the reaction temperature was controlled at 5℃; and the sample rotation speed was 20 r / min to 100 r / min.

[0085] First, inert gas krypton (Kr) is introduced into the auxiliary ion source to generate a neutral ion beam, which pre-cleans the sample surface, removing oxides with a relatively high energy angle. For example, the angle between the sample and the normal direction of the auxiliary ion source can be between 45° and 75°. Then, inert gas krypton (Kr) is introduced into the sputtering ion source to generate a neutral ion beam that bombards the tungsten target, pre-cleaning the target and removing impurities from its surface. Next, a fixed angle greater than 15° is maintained between the sample and the normal direction of the auxiliary ion source, and inert gas krypton (Kr) is introduced into the sputtering ion source to generate a sputtering ion beam. A reactive gas including propane (C3H8) is introduced into the auxiliary ion source to form a reactive ion beam. This reactive ion beam then bombards the tungsten target surface, generating sputtered particles. Finally, the sputtered tungsten particles, under the reaction and impetus of the reactive ion beam, are deposited on the pre-cleaned sample surface, forming a tungsten carbide thin film of 20 nm to 150 nm. Optionally, after pre-cleaning the sample surface, the angle between the sample and the normal direction of the auxiliary ion source can be adjusted to a preset value.

[0086] Example 3: The energy of the sputtered ion beam was set to 1000 eV and the current density was 0.4 A; the energy of the ion beam generated by the auxiliary ion source was set to 200 eV; the reaction temperature was controlled at 300℃; and the sample rotation speed was 20 r / min to 100 r / min.

[0087] First, inert gas xenon (Xe) is introduced into the auxiliary ion source to generate a neutral ion beam, which pre-cleans the sample surface, removing oxides at a relatively high energy angle. For example, the angle between the sample and the normal direction of the auxiliary ion source can be between 45° and 75°. Then, inert gas xenon (Xe) is introduced into the sputtering ion source to generate a neutral ion beam that bombards the tungsten target, pre-cleaning the target and removing impurities from its surface. Next, a fixed angle greater than 15° is formed between the sample and the normal direction of the auxiliary ion source, and inert gas xenon (Xe) is introduced into the sputtering ion source to generate a sputtering ion beam. A reactive gas including acetylene (C2H2) is introduced into the auxiliary ion source to form a reactive ion beam. Subsequently, the sputtering ion beam bombards the surface of the tungsten target, generating sputtered particles. Finally, the tungsten particles sputtered from the target are deposited on the pre-cleaned sample surface under the reaction and impetus of the reactive ion beam, forming a tungsten carbide thin film of 20 nm to 150 nm. Optionally, after pre-cleaning the sample surface, the angle between the sample and the normal direction of the auxiliary ion source can be adjusted to a preset value.

[0088] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for the semiconductor device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiments. Those skilled in the art can understand and implement this without creative effort.

[0089] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing a tungsten carbide thin film, characterized in that, The method includes: An inert gas is introduced into the auxiliary ion source to pre-clean the sample, and an inert gas is introduced into the sputtering ion source to pre-clean the target surface; the target is a tungsten target. An inert gas is introduced into the sputtering ion source to form a sputtering ion beam; a reactive gas is introduced into the auxiliary ion source to form a reactive ion beam; the reactive gas includes a carbon-based gas. The sputtered ion beam bombards the target surface, generating sputtered particles; The sputtered particles react chemically with the reactive ion beam to deposit a tungsten carbide thin film on the sample surface.

2. The method according to claim 1, characterized in that, The sputtered particles chemically react with the reactive ion beam to deposit a tungsten carbide thin film on the sample surface, including: The sputtered particles react chemically with the reactive ion beam to deposit a tungsten carbide film on the sample surface at a preset deposition rate; the preset deposition rate is selected from 1.5 nm / min to 10 nm / min.

3. The method according to claim 1, characterized in that, Before introducing an inert gas into the auxiliary ion source to pre-clean the sample, and before introducing an inert gas into the sputtering ion source to pre-clean the target surface, the method further includes: Adjust the ion beam deposition angle and the sample revolution angle; the ion beam deposition angle is the angle between the sample and the normal direction of the auxiliary ion source; the sample revolution angle is driven by electrodes and is selected from the range of -90° to 60°.

4. The method according to claim 1, characterized in that, Before the sputtered particles chemically react with the reactive ion beam to deposit a tungsten carbide thin film on the sample surface, the method further includes: The sample is controlled to rotate about its central axis.

5. The method according to claim 1, characterized in that, Before introducing an inert gas into the sputtering ion source to form a sputtering ion beam, the method further includes: The energy and energy density of the reactive ion beam are adjusted based on the target roughness.

6. The method according to claim 1, characterized in that, Before introducing an inert gas into the sputtering ion source to form a sputtered ion beam, and introducing a reactive gas into the auxiliary ion source to form a reactive ion beam, the method further includes: The reaction temperature is controlled by a cooling system and a heating stage; the reaction temperature is selected between 5°C and 350°C.

7. The method according to claim 1, characterized in that, The thickness of the tungsten carbide film is in the range of 10 nm to 500 nm.

8. The method according to claim 1, characterized in that, The carbon-based gas is methane, propane, or acetylene.

9. The method according to claim 1, characterized in that, The reactant gases include carbon-based gases and inert gases, and the flow rate ratio of the carbon-based gas to the inert gas is selected from 0.5 to 2.

10. The method according to claim 1, characterized in that, The size of the sputtered ion beam spot is smaller than the size of the target material.

11. The method according to claim 1, characterized in that, The energy of the reactive ion beam is less than or equal to 200 eV.

12. The method according to claim 1, characterized in that, The energy of the sputtered ion beam is selected from the range of 400 eV to 1000 eV.

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