A physical vapor deposition method for improving step coverage

Abstract

The present application provides a physical vapor deposition method for improving step coverage. First, a first inert gas and a halogen gas are introduced into a magnetron sputtering cavity to form a metal halide film layer on the surface of a target material. Second, a second inert gas is introduced into the magnetron sputtering cavity to remove the metal halide film layer and obtain a rough target material surface. Finally, a metal thin film is sputtered. In the present application, a metal halide film layer is sputtered on the surface of the target material, and then the metal halide film layer is removed, so that the surface of the target material has a certain roughness, and the atoms sputtered from the surface of the target material are still symmetrically distributed around the normal line of the surface of the target material. This makes the sputtered atoms migrate into the micropores or grooves at a large incident angle with the wafer surface after moving away from the target surface, thereby improving the step coverage. The present application does not need to additionally add special magnetron controllers, set up a carrier radio frequency power, and increase the structure of a collimator, etc., greatly reducing the process complexity and cost.

Description

Technical Field

[0001] This invention belongs to the field of magnetron sputtering technology, and particularly relates to a physical vapor deposition method for improving step coverage. Background Technology

[0002] In magnetron sputtering, the emission direction distribution of sputtered atoms is related to the incident direction, ion energy, target morphology, etc.

[0003] Test data shows that the distribution of sputtered atoms in different directions generally follows a cosine function (cos... n The θ) rule, where θ is the angle between the emission direction and the target surface normal, and the magnitude of the exponent n is related to the ion energy. For example... Figure 1 As shown, for a specific ion / atom combination, within a certain energy range, n=1, and the sputtered atom distribution resembles a spherical surface. However, for sputtering lower and higher energy ions, the n values ​​are less than and greater than 1, respectively, and the atom distributions sputtered by lower and higher energy ions resemble ellipsoids, but the former is offset laterally, while the latter is offset longitudinally. When the ion energy is low, its incident direction may affect the angular distribution of sputtered atoms; the atom distribution sputtered by obliquely incident ions may shift towards the reflection angle direction. Higher energy ions penetrate deeper into the target surface, and after multiple collisions and scattering, the atom exit direction is biased towards the target surface normal direction. According to... Figure 1 Subcosine-distributed sputtered atoms migrate more to areas outside the wafer, resulting in lower atom utilization compared to supercosine-distributed atom utilization. Furthermore, subcosine-distributed sputtered atoms move at a larger incident angle relative to the wafer surface, thus their step coverage for filling vias and trenches is also lower than that of supercosine-distributed sputtered atoms.

[0004] Experiments show that, Figure 2 As shown, the angular distribution of atoms sputtered from smooth and rough surfaces is significantly different. For the same obliquely incident argon ions, the atomic distribution sputtered from a smooth target surface is offset towards the reflection angle direction, while the atoms emitted from a rough surface are still symmetrically distributed with the target surface normal as the axis.

[0005] In existing technologies, to increase the step coverage of vias and trenches, it is often necessary to change the magnetic field distribution, i.e., the magnetron design and magnet arrangement, thereby altering the ejection direction of sputtered atoms and allowing more atoms to deposit into the micro-holes or trenches on the wafer surface. However, changes to the magnetron design often introduce other negative issues, such as variations in thin film deposition uniformity, which increases process costs. Additionally, to further increase the step coverage of vias and trenches, a collimator structure can be added, but this filters out a large number of sputtered atoms, significantly reducing atom utilization. Applying radio frequency (RF) power to the wafer stage can also improve step coverage, but this requires an additional RF power supply and matching network, greatly increasing equipment costs. SUMMARY

[0006] To solve at least one technical problem in the prior art, a physical vapor deposition method for improving step coverage is provided to effectively improve step coverage. To achieve the above technical purpose, the technical solution adopted by the embodiments of the present application is as follows:

[0007] The embodiments of the present application provide a physical vapor deposition method for improving step coverage. First, a first inert gas and a halogen gas are introduced into a magnetron sputtering cavity to form a metal halide film layer on the surface of a target material. Second, a second inert gas is introduced into the magnetron sputtering cavity to remove the metal halide film layer and obtain a rough target material surface. Finally, a metal thin film is sputtered.

[0008] Further, in step S1, pre-sputtering: a target material is selected, the distance between the target material and a wafer is adjusted, the substrate temperature is set to a preset temperature, the cavity vacuum degree is set to a preset vacuum degree, and the target material is pre-sputtered at a preset power.

[0009] In step S2, a metal halide film layer is prepared: the first inert gas is introduced into the magnetron sputtering cavity, a first radio frequency power P1 is applied to the target material, the halogen gas is introduced into the cavity, and a first sputtering time T1 is set to form a metal halide film layer on the surface of the target material.

[0010] In step S3, the metal halide film layer is removed: a second inert gas is introduced into the magnetron sputtering cavity, a second radio frequency power P2 is applied to the target material, and a second sputtering time T2 is set to remove the metal halide film layer and obtain a rough target material surface. Mark W2 = P2*T2, and the multiple of W2 is X, where X is a positive integer.

[0011] In step S4, a metal thin film is sputtered: a third inert gas is introduced into the magnetron sputtering cavity, a third radio frequency power P3 is applied to the target material, and a third sputtering time T3 is set. Mark W3 = P3*T3, the sputtering number is N, and N is a positive integer.

[0012] When NW3 < XW2, step S4 is implemented to obtain a metal thin film.

[0013] When NW3 > XW2, steps S2, S3, and S4 are sequentially implemented to obtain a metal thin film.

[0014] Further, the relative atomic mass of the second inert gas is greater than the relative atomic mass of the first inert gas.

[0015] And / or, the relative atomic mass of the third inert gas is greater than the relative atomic mass of the first inert gas.

[0016] And / or, the relative atomic mass of the second inert gas is greater than or equal to the relative atomic mass of the third inert gas.

[0017] Further, in step S1, the target material includes at least one of titanium, copper, aluminum, aluminum alloy, tantalum, nickel, silver, gold, platinum;

[0018] And / or, the diameter of the target material is 320-321mm,

[0019] And / or, the wafer is selected from at least one of silicon, gallium arsenide, silicon carbide, quartz glass, aluminum oxide, indium phosphide, gallium nitride, gallium oxide, aluminum nitride;

[0020] And / or, the distance between the target material and the wafer is 150-450mm.

[0021] And / or, the preset temperature is 25-300℃;

[0022] And / or, the preset vacuum degree is 5.0x10 -8 Torr or less;

[0023] And / or, the preset power of pre-sputtering is 3000W.

[0024] Further, in step S2, the first inert gas includes at least one of helium and neon;

[0025] And / or, the flow rate of the first inert gas is 50-200sccm;

[0026] And / or, the halogen gas includes at least one of chlorine and bromine;

[0027] And / or, the flow rate of the halogen gas is 0.5-5sccm.

[0028] Further, in step S2, the first radio frequency power P1 is 100-1000W;

[0029] And / or, the cavity reaction pressure is 4.5-22mTorr;

[0030] And / or, the first time T1 is 5-10min.

[0031] Further, in step S3, the second inert gas includes at least one of xenon and krypton;

[0032] And / or, the flow rate of the second inert gas is 20-60sccm.

[0033] Further, in step S3, the second radio frequency power P2 is 1000-10000W;

[0034] And / or, the cavity reaction pressure is 1.4–4.2 mTorr;

[0035] And / or, the second time T2 is 5 to 10 minutes.

[0036] Furthermore, in step S4, the third inert gas includes argon;

[0037] And / or, the flow rate of the third inert gas is 20 to 60 sccm.

[0038] Furthermore, in step S4, the third radio frequency power P3 is 3000~10000W;

[0039] And / or, the cavity reaction pressure is 1.4–4.2 mTorr;

[0040] And / or, the third time T3 is 1 to 5 minutes.

[0041] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows:

[0042] This invention pre-treats the target surface under different inert gas environments—specifically, by sputtering a metal halide film onto the target surface and then removing it—to create a certain surface roughness. This ensures that the sputtered atoms are symmetrically distributed around the target surface normal. This allows the sputtered atoms to migrate at a larger incident angle to the wafer surface into micropores or trenches after moving away from the target surface, thereby improving step coverage. This invention eliminates the need for additional special magnetrons, stage RF power settings, and collimator structures, significantly reducing process complexity and cost. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the emission angle distribution of sputtered atoms in the background technology.

[0044] Figure 2 The background section compares the angular distribution of sputtered atoms when argon ions bombard smooth and rough target surfaces, respectively.

[0045] Figure 3 Schematic diagram of the step coverage section in Embodiment 1 and Comparative Example 1 of the present invention.

[0046] Figure 4 This is a SEM (scanning electron microscope) image of the titanium thin film in Example 1 of the present invention.

[0047] Figure 5 This is a SEM (scanning electron microscope) image of the titanium thin film in Comparative Example 1 of the present invention. Detailed Implementation

[0048] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0049] In addition, it should be understood that those skilled in the art can make various modifications or changes to the present application after reading the disclosure of the present application, and these equivalent forms also fall within the protection scope defined by the present application.

[0050] The embodiment of the present application provides a physical vapor deposition method for improving step coverage. First, a first inert gas and a halogen gas are introduced into a magnetron sputtering cavity to form a metal halide film layer on the surface of a target material. Second, a second inert gas is introduced into the magnetron sputtering cavity to remove the metal halide film layer and obtain a rough target material surface. Finally, a metal thin film is sputtered.

[0051] Further, in step S1, pre-sputtering: a target material is selected, the distance between the target material and a wafer is adjusted, and the target material is pre-sputtered.

[0052] In step S2, a metal halide film layer is prepared: the first inert gas is introduced into the magnetron sputtering cavity, a first radio frequency power P1 is applied to the target material, the halogen gas is introduced into the cavity, sputtering is performed for a first time T1, and a metal halide film layer is formed on the surface of the target material.

[0053] In a specific embodiment, the halogen gas is taken as an example of chlorine gas. After helium (He) forms a gas glow discharge plasma under the first radio frequency power, Cl2 in the plasma collides with electrons to split Cl2 molecules to generate a large number of high-reactivity free radicals, i.e., e+Cl2→Cl+Cl+e. The metal target material surface reacts with Cl free radicals to form a certain thickness of MCl X film (M is metal), and the metal target material surface produces a reduced gap or an expanded gap, thereby changing the surface morphology of the metal target material.

[0054] Since the atomic mass of He is very low, the sputtering yield of metal chloride produced by He ion bombardment on the surface of the metal target material is very low. Furthermore, after the chlorine free radicals react with the metal atoms on the target surface to form metal chlorides, the He ions have difficulty in producing bombardment effects on the target surface, and the metal chlorides on the target surface can be stably formed and shaped.

[0055] At the same time, the chlorinated film can prevent further reaction on the surface of the metal target material to a certain extent.

[0056] Step S3, removing the metal halide film layer: a second inert gas is introduced into the magnetron sputtering cavity, and a second radio frequency power P2 is applied to the target material, and sputtering is performed for a second time T2 to remove the metal halide film layer, thereby obtaining a rough target material surface, and W2=P2*T2, and the multiple of W2 is X, and X is a positive integer;

[0057] In a specific embodiment, the second inert gas is xenon (Xe), and the atomic mass of Xe is high. After the second radio frequency power is applied, a gas glow discharge plasma is formed. Due to the high mass of Xe positive ions, the bombardment effect on the target material surface is stronger, more obvious, and the sputtering yield is higher. The MCl X The metal halide film layer is removed from the metal target surface, and a rough metal target material surface is obtained.

[0058] Step S4, sputtering a metal thin film: a third inert gas is introduced into the magnetron sputtering cavity, and a third radio frequency power P3 is applied to the target material, and sputtering is performed for a third time T3, and W3=P3*T3, and the sputtering number is N, and N is a positive integer;

[0059] When NW3XW2, step S4 is performed to obtain a metal thin film.

[0060] When NW3>XW2, steps S2, S3, and S4 are sequentially performed to obtain a metal thin film.

[0061] After the argon (Ar) is introduced and the third radio frequency power is applied, a gas glow discharge plasma is formed. The Ar is ionized into Ar positive ions and bombards the rough metal target material, generating metal atoms with a large incident angle with the wafer surface.

[0062] The sputtering is ensured when NW3XW2 to ensure the roughness level of the target material surface, thereby ensuring the strong directionality of the sputtered atoms, and thereby a large incident angle with the wafer surface. This sputtering condition has a significant improvement effect on the step coverage of the hole filling process.

[0063] Further, the relative atomic mass of the second inert gas is greater than the relative atomic mass of the first inert gas;

[0064] And / or, the relative atomic mass of the third inert gas is greater than the relative atomic mass of the first inert gas;

[0065] And / or, the relative atomic mass of the second inert gas is greater than or equal to the relative atomic mass of the third inert gas.

[0066] Further, in step S1, the target material includes at least one of titanium, copper, aluminum, aluminum alloy, tantalum, nickel, silver, gold, and platinum.

[0067] And / or, the target material diameter is 320-321mm,

[0068] And / or, the wafer is selected from at least one of silicon, gallium arsenide, silicon carbide, quartz glass, aluminum oxide, indium phosphide, gallium nitride, gallium oxide, aluminum nitride;

[0069] And / or, the distance between the target material and the wafer is 150-450mm, for example, it can be 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, 450mm, etc.

[0070] And / or, the preset temperature is 25-300℃, for example, it can be 25℃, 50℃, 100℃, 150℃, 200℃, 250℃, 300℃, etc.

[0071] And / or, the preset vacuum degree is 5.0x10 -8 Torr, for example, it can be 1x10 -8 Torr, 2x10 - 8 Torr, 3x10 -8 Torr, 4x10 -8 Torr, etc.

[0072] And / or, the preset power of pre-sputtering is 3000W.

[0073] In a specific embodiment, the target material is copper, the diameter is 320mm, the wafer is silicon, the distance between the target material and the wafer is 200mm, the preset temperature is 50℃, the preset vacuum degree is 1x10 -8 Torr, and the preset power is 3000W.

[0074] In another specific embodiment, the target material is titanium, the diameter is 321mm, the wafer is gallium nitride, the distance between the target material and the wafer is 400mm, the preset temperature is 100℃, the preset vacuum degree is 3x10 -8 Torr, and the preset power is 3000W.

[0075] Further, in step S2, the first inert gas includes at least one of helium and neon.

[0076] And / or, the flow rate of the first inert gas is 50-200sccm, for example, it can be 50sccm, 70sccm, 90sccm, 100sccm, 120sccm, 140sccm, 160sccm, 180sccm, 200sccm, etc.

[0077] And / or, the halogen gas includes at least one of chlorine and bromine.

[0078] and / or, the flow rate of the halogen gas is 0.5-5 sccm, for example, it can be 0.5 sccm, 1.0 sccm, 1.5 sccm, 2.0 sccm, 3.0 sccm, 3.5 sccm, 4.0 sccm, 4.5 sccm, 5.0 sccm, etc.

[0079] In a specific embodiment, the first inert gas is helium, and the flow rate is 50 sccm; the halogen gas is chlorine, and the flow rate is 1.0 sccm.

[0080] In another specific embodiment, the first inert gas is neon, and the flow rate is 160 sccm; the halogen gas is bromine, and the flow rate is 4.0 sccm.

[0081] Further, in step S2, the first radio frequency power P1 is 100-1000 W, for example, it can be 100 W, 200 W, 300 W, 400 W, 500 W, 600 W, 700 W, 800 W, 900 W, 1000 W, etc.

[0082] and / or, the cavity reaction pressure is 4.5-22 mTorr, for example, it can be 4.5 mTorr, 10 mTorr, 15 mTorr, 20 mTorr, 22 mTorr, etc.

[0083] and / or, the first time T1 is 5-10 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc.

[0084] In a specific embodiment, the first radio frequency power P1 is 100 W, the cavity reaction pressure is 10 mTorr, and the first time T1 is 6 min.

[0085] In another specific embodiment, the first radio frequency power P1 is 500 W, the cavity reaction pressure is 20 mTorr, and the first time T1 is 8 min.

[0086] Further, in step S3, the second inert gas includes at least one of xenon and krypton;

[0087] and / or, the flow rate of the second inert gas is 20-60 sccm, for example, it can be 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, etc.

[0088] In a specific embodiment, the second inert gas is xenon, and the flow rate is 20 sccm.

[0089] In another specific embodiment, the second inert gas is krypton gas, and the flow rate is 50 seem.

[0090] Further, in step S3, the second RF power P2 is 1000-10000 W, for example, 1000 W, 2000 W, 3000 W, 4000 W, 5000 W, 6000 W, 7000 W, 8000 W, 9000 W, 10000 W, etc.

[0091] Further, in step S3, the second RF power P2 is 1000-10000 W, for example, 1000 W, 2000 W, 3000 W, 4000 W, 5000 W, 6000 W, 7000 W, 8000 W, 9000 W, 10000 W, etc.

[0092] Further, in step S3, the second RF power P2 is 1000-10000 W, for example, 1000 W, 2000 W, 3000 W, 4000 W, 5000 W, 6000 W, 7000 W, 8000 W, 9000 W, 10000 W, etc.

[0093] In one specific embodiment, the second RF power P2 is 2000 W, the chamber reaction pressure is 2.5 mTorr, and the second time T2 is 7 min.

[0094] In another specific embodiment, the second RF power P2 is 4000 W, the chamber reaction pressure is 3.5 mTorr, and the second time T2 is 10 min.

[0095] Further, in step S4, the third inert gas includes argon gas.

[0096] Further, in step S4, the third inert gas includes argon gas.

[0097] Further, in step S4, the third RF power P3 is 3000-10000 W, for example, 3000 W, 4000 W, 5000 W, 6000 W, 7000 W, 8000 W, 9000 W, 10000 W, etc.

[0098] Further, in step S4, the third RF power P3 is 3000-10000 W, for example, 3000 W, 4000 W, 5000 W, 6000 W, 7000 W, 8000 W, 9000 W, 10000 W, etc.

[0099] Further, in step S4, the third RF power P3 is 3000-10000 W, for example, 3000 W, 4000 W, 5000 W, 6000 W, 7000 W, 8000 W, 9000 W, 10000 W, etc.

[0100] In a specific embodiment, the third radio frequency power P3 is 4000 W, the chamber reaction pressure is 2 mTorr, and the third time T3 is 2 min.

[0101] In another specific embodiment, the third radio frequency power P3 is 6000 W, the chamber reaction pressure is 3 mTorr, and the third time T3 is 5 min.

[0102] In the following specific embodiments, the operations not specified are carried out under conventional conditions or under the conditions recommended by the manufacturer. All raw materials not specified by manufacturer and specifications are conventional products that can be purchased on the market. Example 1

[0103] A physical vapor deposition method for improving step coverage, comprising the following steps:

[0104] Step S1, pre-sputtering: a titanium metal target is selected, the target material has a diameter of 320 mm, the distance between the target material and the wafer is set to 250 mm, the substrate temperature is set to 200°C, the chamber vacuum degree is set to 4.0x10 -8 Torr, the pre-sputtering power is 3000 W, and the pre-sputtering target material is 1 min;

[0105] Step S2, preparing a metal halide film layer TiCl X : helium gas with a flow rate of 50 sccm and chlorine gas with a flow rate of 1.5 sccm are introduced into the magnetron sputtering chamber, the chamber reaction pressure is set to 4.5 mTorr, the first radio frequency power is set to 200 W, and sputtering is performed for 5 min to form a metal halide film layer TiCl X on the surface of the target material;

[0106] Step S3, removing the metal halide film layer TiCl X : xenon gas with a flow rate of 30 sccm is introduced into the magnetron sputtering chamber, the chamber reaction pressure is set to 2.0 mTorr, the second radio frequency power is set to 3000 W, and sputtering is performed for 5 min to remove the metal halide film layer TiCl X , thereby obtaining a rough target material surface;

[0107] Step S4, sputtering a metal thin film: argon gas with a flow rate of 30 sccm is introduced into the magnetron sputtering chamber, the chamber reaction pressure is set to 2.0 mTorr, the third radio frequency power is set to 9000 W, and sputtering is performed for 1.5 min to obtain a titanium metal thin film. Example 2

[0108] A physical vapor deposition method for improving step coverage, comprising the following steps:

[0109] Step S1, pre-sputtering: a metal titanium target is selected, the target material has a diameter of 320 mm, the distance between the target material and the wafer is set to 250 mm, the substrate temperature is set to 200°C, the cavity vacuum degree is set to 1.0*10 -8 Torr, the pre-sputtering power is 3000W, and the pre-sputtering target material is 1 min;

[0110] Step S2, preparing a metal halide film layer TiCl X : helium gas with a flow rate of 100sccm and chlorine gas with a flow rate of 3.5sccm are introduced into the magnetron sputtering cavity, the cavity reaction pressure is set to 10mTorr, the first radio frequency power is 500W, sputtering is performed for 5 min, and a metal halide film layer TiCl X is formed on the surface of the target material;

[0111] Step S3, removing the metal halide film layer TiCl X : xenon gas with a flow rate of 50sccm is introduced into the magnetron sputtering cavity, the cavity reaction pressure is set to 3.0mTorr, the second radio frequency power is 5000W, sputtering is performed for 8 min, and the metal halide film layer TiCl X is removed to obtain a rough target material surface;

[0112] Step S4, sputtering a metal thin film: argon gas with a flow rate of 40sccm is introduced into the magnetron sputtering cavity, the cavity reaction pressure is set to 3.0mTorr, the third radio frequency power is 9000W, sputtering is performed for 3.5 min, and a metal titanium thin film is obtained. Example 3

[0113] A physical vapor deposition method for improving step coverage, comprising the following steps:

[0114] Step S1, pre-sputtering: a metal titanium target is selected, the target material has a diameter of 320 mm, the distance between the target material and the wafer is set to 250 mm, the substrate temperature is set to 200°C, the cavity vacuum degree is set to 4.0*10 -8 Torr, the pre-sputtering power is 3000W, and the pre-sputtering target material is 1 min;

[0115] Step S2, preparing a metal halide film layer TiCl X : helium gas with a flow rate of 50sccm and chlorine gas with a flow rate of 1.5sccm are introduced into the magnetron sputtering cavity, the cavity reaction pressure is set to 4.5mTorr, the first radio frequency power is 200W, sputtering is performed for 5 min, and a metal halide film layer TiCl X is formed on the surface of the target material;

[0116] Step S3, removing the metal halide film layer TiCl X: The sputtering power of the second radio frequency is 3000 W, and sputtering is performed for 5 min to remove the metal halide film TiCl X , so as to obtain a rough target surface.

[0117] Step S4, sputtering a metal thin film: argon gas with a flow rate of 30 seem is introduced into the magnetron sputtering cavity, the cavity reaction pressure is set to 2.0 mTorr, the third radio frequency power is 9000 W, and sputtering is performed for 5 min to obtain a metal titanium thin film.

[0118] Comparative Example 1

[0119] A physical vapor deposition method, comprising the following steps:

[0120] Step S1, pre-sputtering: a metal titanium target is selected, the target has a diameter of 320 mm, the distance between the target and the wafer carrier is 250 mm, the substrate temperature is set to 200 ℃, the cavity vacuum degree is set to 4.0 x 10 -8 Torr, the pre-sputtering power is 3000 W, and pre-sputtering is performed for 1 min;

[0121] Step S2, sputtering a metal thin film: argon gas with a flow rate of 30 seem is introduced into the magnetron sputtering cavity, the cavity reaction pressure is set to 2.0 mTorr, the target sputtering power is 9000 W, and sputtering is performed for 2 min to obtain a metal titanium thin film.

[0122] Application Example

[0123] The metal titanium thin films provided by the application example 1 and the comparative example 1 are tested. Specifically, the metal titanium thin films with the same area prepared in the application example 1 and the comparative example 1 are selected as samples, and the step coverage of the samples is tested. The step coverage is shown in Table 1.

[0124] Step coverage: the cross-sectional film thickness of the wafer surface micropore is observed under a scanning electron microscope, the film thickness of the top plane, the sidewall and the bottom of the micropore are measured respectively, the measurement points are shown in Figure 3 , and the ratio of the film thickness of the sidewall to the top plane and the ratio of the film thickness of the bottom to the top plane are calculated respectively, that is, the step coverage, wherein the film thickness of the sidewall is the average value of the film thickness of the two sidewalls. The testing instrument of the scanning electron microscope (SEM) is Hitachi S-4800.

[0125] Table 1 Step coverage of the metal thin film in the application example 1 and the comparative example 1

[0126]

[0127] From Table 1, Figure 4and Figure 5 It can be seen that the step coverage of the metal titanium film prepared by the conventional physical vapor deposition method adopted in Comparative Example 1 is low, there is almost no film deposition in the middle and lower parts of the sidewall, and the bottom coverage is less than 25%, while the step coverage is obviously improved by the physical vapor deposition method for improving step coverage adopted in Example 1 of the present application, the sidewall is continuous and the coverage at the lowest part is more than 15% and the bottom coverage is more than 50%, which indicates that the emission direction of the atoms on the target surface is close to the normal direction of the target surface, that is, the distribution direction of the atoms emitted from the target surface is close to the hypercosine distribution as shown in FIG. 2, and thus the step coverage can be improved. Figure 1

[0128] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the examples, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.​

Claims

1. A physical vapor deposition method for improving step coverage, characterized by, The method comprises the following steps: Step S1, pre-sputtering: selecting a target material, adjusting the distance between the target material and the wafer, setting the substrate temperature to a preset temperature, the cavity vacuum degree to a preset vacuum degree, pre-sputtering the target material under a preset power; Step S2, preparing a metal halide film layer: introducing a first inert gas into the magnetron sputtering cavity, and applying a first radio frequency power P1 to the target material, while introducing a halogen gas into the cavity, sputtering for a first time T1, and forming a metal halide film layer on the surface of the target material; The first inert gas comprises at least one of helium and neon; The halogen gas comprises at least one of chlorine and bromine; Step S3, removing the metal halide film layer: introducing a second inert gas into the magnetron sputtering cavity, and applying a second radio frequency power P2 to the target material, sputtering for a second time T2, the second radio frequency power P2 is 1000-10000W, and the second time T2 is 5-10min, to remove the metal halide film layer and obtain a rough target material surface, The relative atomic mass of the second inert gas is greater than that of the first inert gas; The second inert gas comprises at least one of xenon and krypton; Step S4, sputtering a metal thin film: introducing a third inert gas into the magnetron sputtering cavity, and applying a third radio frequency power P3 to the target material, sputtering for a third time T3, the third radio frequency power P3 is 3000-10000W, the third time T3 is 1-5min, the relative atomic mass of the third inert gas is greater than that of the first inert gas, and the relative atomic mass of the second inert gas is greater than or equal to that of the third inert gas; The third inert gas comprises argon.

2. The physical vapor deposition method for improving step coverage according to claim 1, wherein, In step S1, the target material comprises at least one of titanium, copper, aluminum, aluminum alloy, tantalum, nickel, silver, gold, platinum; And / or, the diameter of the target material is 320-321mm, And / or, the wafer is selected from at least one of silicon, gallium arsenide, silicon carbide, quartz glass, aluminum oxide, indium phosphide, gallium nitride, gallium oxide, aluminum nitride; And / or, the distance between the target material and the wafer is 150-450mm; And / or, the preset temperature is 25-300℃; And / or, the preset vacuum degree is 5.0x10 -8 Torr below; And / or, the preset power of pre-sputtering is 3000W.

3. The physical vapor deposition method for improving step coverage according to claim 1, wherein, In step S2, the flow rate of the first inert gas is 50-200sccm; And / or, the flow rate of the halogen gas is 0.5-5sccm.

4. The physical vapor deposition method for improving step coverage according to claim 1, wherein, In step S2, the first radio frequency power P1 is 100-1000W; And / or, the cavity reaction pressure is 4.5-22mTorr; And / or, the first time T1 is 5-10min.

5. The physical vapor deposition method for improving step coverage according to claim 1, wherein, The flow rate of the second inert gas is 20-60 seem in step S3.

6. The physical vapor deposition method for improving step coverage according to claim 1, wherein The chamber reaction pressure is 1.4-4.2 mTorr in step S3.

7. The physical vapor deposition method for improving step coverage according to claim 1, wherein The flow rate of the third inert gas is 20-60 seem in step S4.

8. The physical vapor deposition method for improving step coverage according to claim 1, wherein The chamber reaction pressure is 1.4-4.2 mTorr in step S4.

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