Physical vapor deposition method for improving step coverage rate

Abstract

The invention provides a physical vapor deposition method for improving step coverage rate, which comprises the following steps of: firstly, introducing first inert gas and halogen gas into a magnetron sputtering cavity, and forming a metal halide film layer on the surface of a target material; secondly, second inert gas is introduced into the magnetron sputtering cavity, the metal halide film layer is removed, and a rough target material surface is obtained; and finally, sputtering a metal film. According to the embodiment of the invention, the 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 certain roughness, and atoms sputtered from the surface of the target material are still distributed symmetrically by taking the normal of the surface of the target material as an axis. The sputtering atoms are moved to the micropores or the grooves at a large incidence angle with the surface of the wafer after being far away from the target surface, so that the step coverage rate is improved, a special magnetic controller does not need to be additionally arranged, carrier radio frequency power does not need to be arranged, and a collimator structure does not need to be additionally arranged, so that the process complexity is greatly reduced, and the cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetron sputtering, and in particular relates to a physical vapor deposition method for improving step coverage. Background Art

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

[0003] Test data show that the distribution of sputtered atoms in different directions generally follows the cosine function (cos n θ) law, where θ is the angle between the emission direction and the target surface normal, and the index n is related to the ion energy. Figure 1 As shown, for a specific ion / atom combination, within a certain energy range, n=1, the distribution of sputtered atoms is similar to a circular sphere, while for lower and higher energy ion sputtering, n values ​​are less than and greater than 1 respectively, and the distribution of atoms sputtered by lower and higher energy ions is similar to an ellipsoid, but the former is offset laterally and the latter is offset longitudinally. When the ion energy is low, its incident direction may affect the angular distribution of sputtered atoms, and the distribution of atoms sputtered by oblique incident ions may move toward the direction of the reflection angle. Higher energy ions penetrate deeper into the target surface, and after multiple collisions and scattering, the atomic emission direction is biased toward the normal direction of the target surface. According to Figure 1 , the sputtered atoms with sub-cosine distribution will migrate more to the area outside the wafer, and the atomic utilization rate is lower than that of the atoms with super-cosine distribution; in addition, the sputtered atoms with sub-cosine distribution move in a direction relative to the wafer surface and will be deposited on the wafer surface at a larger incident angle, so their step coverage of filling holes and grooves is also lower than that of the sputtered atoms with super-cosine distribution.

[0004] Experiments show that Figure 2 As shown in Figure 1, the angular distribution of atoms sputtered from smooth and rough surfaces is significantly different. For the same obliquely incident argon ions, the distribution of atoms sputtered from the smooth target surface is offset in the direction of the reflection angle, while the atoms emitted from the rough surface are still symmetrically distributed with the target surface normal as the axis.

[0005] In the prior art, in order to increase the step coverage of filled holes and grooves, it is often necessary to change the magnetic field distribution, that is, the magnetron design and magnet arrangement, so as to change the emission direction of the sputtered atoms, so that more atoms are deposited in the micropores or grooves on the surface of the wafer. However, design changes of the magnetron often bring other negative problems, such as changes in the uniformity of thin film deposition, which will lead to increased process costs. In addition, in order to increase the step coverage of filled holes and grooves, a collimator structure can also be added, but it will filter out a large number of sputtered atoms and significantly reduce the utilization rate of atoms; if RF power is applied to the wafer carrier, the step coverage can also be improved, but an additional set of RF power supplies and matching networks need to be set up, which greatly increases the equipment cost. Summary of the invention

[0006] In order 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 the step coverage. To achieve the above technical objectives, the technical solution adopted in the embodiment of the present invention is: An embodiment of the present invention 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 chamber to form a metal halide film layer on the surface of a target material; secondly, a second inert gas is introduced into the magnetron sputtering chamber to remove the metal halide film layer to obtain a rough target surface; finally, a metal film is sputtered.

[0007] Further, 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 chamber vacuum to a preset vacuum, and pre-sputtering the target material at a preset power; Step S2, preparing a metal halide film layer: introducing the first inert gas into the magnetron sputtering chamber, applying a first radio frequency power P1 to the target material, and introducing the halogen gas into the chamber at the same time, sputtering for a first time T1, and forming a metal halide film layer on the surface of the target material; Step S3, removing the metal halide film layer: introducing a second inert gas into the magnetron sputtering chamber, applying a second radio frequency power P2 to the target material, and sputtering for a second time T2 to remove the metal halide film layer to obtain a rough target surface, marked as W2=P2*T2, where the multiple of W2 is X, and X is a positive integer; Step S4, sputtering the metal film: introducing a third inert gas into the magnetron sputtering chamber, applying a third radio frequency power P3 to the target material, sputtering for a third time T3, marked W3= P3*T3, the number of sputtering is N, N is a positive integer; When NW3<XW2, step S4 is implemented to obtain a metal film; When NW3>XW2, step S2, step S3, and step S4 are sequentially performed to obtain a metal thin film.

[0008] Further, the relative atomic mass of the second inert gas is greater than the relative atomic mass of the first inert gas; and / or, the relative atomic mass of the third noble gas is greater than the relative atomic mass of the first noble gas; And / or, the relative atomic mass of the second noble gas is greater than or equal to the relative atomic mass of the third noble gas.

[0009] Further, in step S1, the target material includes at least one of titanium, copper, aluminum, aluminum alloy, tantalum, nickel, silver, gold, and platinum; and / or, the target material has a diameter of 320 to 321 mm, 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, and aluminum nitride; And / or, the distance between the target and the wafer is 150-450 mm.

[0010] And / or, the preset temperature is 25 to 300 ℃; And / or, the preset vacuum degree is 5.0×10 -8 Torr or less; And / or, the preset power of pre-sputtering is 3000W.

[0011] Further, in step S2, the first inert gas includes at least one of helium and neon; and / or, the flow rate of the first inert gas is 50 to 200 sccm; And / or, the halogen gas includes at least one of chlorine gas and bromine gas; And / or, the flow rate of the halogen gas is 0.5-5 sccm.

[0012] Further, in step S2, the first radio frequency power P1 is 100 to 1000 W; and / or, the chamber reaction pressure is 4.5 to 22 mTorr; And / or, the first time T1 is 5 to 10 minutes.

[0013] Further, in step S3, the second inert gas includes at least one of xenon and krypton; And / or, the flow rate of the second inert gas is 20-60 sccm.

[0014] Further, in step S3, the second radio frequency power P2 is 1000-10000W; and / or, the chamber reaction pressure is 1.4 to 4.2 mTorr; And / or, the second time T2 is 5 to 10 minutes.

[0015] Further, in step S4, the third inert gas includes argon; And / or, the flow rate of the third inert gas is 20-60 sccm.

[0016] Further, in step S4, the third radio frequency power P3 is 3000-10000W; and / or, the chamber reaction pressure is 1.4 to 4.2 mTorr; And / or, the third time T3 is 1 to 5 minutes.

[0017] The technical solution provided by the embodiment of the present invention has the following beneficial effects: The embodiment of the present invention pre-treats the target surface under different inert gas environments, that is, sputters a metal halide film layer on the target surface and then removes the metal halide film layer, so that the target surface has a certain degree of roughness, and the atoms sputtered from the target surface are still symmetrically distributed with the target surface normal as the axis. This allows the sputtered atoms to migrate to the micropores or grooves at a larger incident angle with the wafer surface after moving away from the target surface, thereby improving the step coverage. The embodiment of the present invention does not require the additional installation of special magnetrons, the setting of the stage RF power, and the addition of collimator structures, etc., which greatly reduces the process complexity and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the emission angle distribution of sputtered atoms in the background technology.

[0019] Figure 2 The figure shows the comparison of the angular distribution of sputtered atoms when argon ions bombard a smooth target surface and a rough target surface in the background technology.

[0020] Figure 3 Schematic diagram of the step coverage cut-off position in Example 1 of the present invention and Comparative Example 1.

[0021] Figure 4 This is a SEM (scanning electron microscope) image of the metal titanium film in Example 1 of the present invention.

[0022] Figure 5 This is a SEM (scanning electron microscope) image of the metal titanium film in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] In addition, it should be understood that after reading the contents disclosed in the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the protection scope defined by the present invention.

[0025] An embodiment of the present invention 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 chamber to form a metal halide film layer on the surface of a target material; secondly, a second inert gas is introduced into the magnetron sputtering chamber to remove the metal halide film layer to obtain a rough target surface; finally, a metal film is sputtered.

[0026] Further, step S1, pre-sputtering: selecting a target material, adjusting the distance between the target material and the wafer, and pre-sputtering the target material; Step S2, preparing a metal halide film layer: introducing the first inert gas into the magnetron sputtering chamber, applying a first radio frequency power P1 to the target material, and introducing the halogen gas into the chamber at the same time, sputtering for a first time T1, and forming a metal halide film layer on the surface of the target material; In a specific embodiment, the halogen gas is chlorine. After the helium (He) forms a gas glow discharge plasma under the first RF power, Cl2 dissociates and collides with electrons in the plasma, causing the Cl2 molecules to split and produce a large number of highly reactive free radicals, namely: e+Cl2→Cl+Cl+e. The surface of the metal target reacts with the Cl free radicals to form MCl of a certain thickness. X The film (M is metal) causes the surface of the metal target to shrink or expand, thereby changing the surface morphology of the metal target.

[0027] Since the mass of He atoms is very low, the sputtering yield of metal chloride produced by He ion bombardment on the surface of metal target is very low. After the chlorine radicals react with the metal atoms on the target surface to form metal chloride, it is difficult for He ions to bombard the target surface, and the metal chloride on the target surface can be stably formed and maintain its shape.

[0028] At the same time, the chlorinated film can prevent further reaction on the surface of the metal target to a certain extent.

[0029] Step S3, removing the metal halide film layer: introducing a second inert gas into the magnetron sputtering chamber, applying a second radio frequency power P2 to the target material, and sputtering for a second time T2 to remove the metal halide film layer to obtain a rough target surface, marked as W2=P2*T2, where the multiple of W2 is X, and X is a positive integer; In a specific embodiment, the second inert gas is xenon (Xe) as an example. Xe atoms have a high mass. After the second RF power is applied, a gas glow discharge plasma is formed. Since the mass of Xe positive ions is high, the bombardment effect on the target surface is stronger and more obvious, and the sputtering yield is higher, which can convert MCl X It is sputtered away from the metal target surface, thereby obtaining a rough metal target surface.

[0030] Step S4, sputtering the metal film: introducing a third inert gas into the magnetron sputtering chamber, applying a third radio frequency power P3 to the target material, sputtering for a third time T3, marked W3= P3*T3, the number of sputtering is N, N is a positive integer; When NW3<XW2, step S4 is implemented to obtain a metal film; When NW3>XW2, step S2, step S3, and step S4 are sequentially performed to obtain a metal thin film.

[0031] After argon (Ar) is introduced and the third RF power is applied, a gas glow discharge plasma is formed. Ar is ionized into Ar positive ions and bombards the metal target with a rougher surface, generating metal atoms with a larger incident angle to the wafer surface.

[0032] Ensuring sputtering when NW3 < XW2 is to ensure the roughness level of the target surface, thereby ensuring that the sputtered atoms have a strong emission directionality and a larger incident angle with the wafer surface. This sputtering condition has a significant effect on improving the step coverage of the hole filling process.

[0033] Further, the relative atomic mass of the second inert gas is greater than the relative atomic mass of the first inert gas; and / or, the relative atomic mass of the third noble gas is greater than the relative atomic mass of the first noble gas; And / or, the relative atomic mass of the second noble gas is greater than or equal to the relative atomic mass of the third noble gas.

[0034] Further, in step S1, the target material includes at least one of titanium, copper, aluminum, aluminum alloy, tantalum, nickel, silver, gold, and platinum; and / or, the target material has a diameter of 320 to 321 mm, 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, and aluminum nitride; And / or, the distance between the target and the wafer is 150-450 mm, for example, 150 mm, 200 mm, 250 mm, 300 mm, 350 mm, 400 mm, 450 mm, etc.

[0035] And / or, the preset temperature is 25-300°C, for example, 25°C, 50°C, 100°C, 150°C, 200°C, 250°C, 300°C, etc.; And / or, the preset vacuum degree is 5.0×10 -8 Torr or less, for example, 1×10 -8 Torr, 2×10 - 8Torr, 3×10 -8 Torr, 4×10 -8 Torr et al. and / or, the preset power of the pre-sputtering is 3000W; In a specific embodiment, the target material is copper and has a diameter of 320 mm, the wafer is silicon, the interval between the target material and the wafer is 200 mm, the preset temperature is 50° C., and the preset vacuum degree is 1×10 -8 Torr, the preset power is 3000W; In another specific embodiment, the target material is titanium and has a diameter of 321 mm, the wafer is gallium nitride, the interval between the target material and the wafer is 400 mm, the preset temperature is 100° C., and the preset vacuum degree is 3×10 -8 Torr, the preset power is 3000W; Further, in step S2, the first inert gas includes at least one of helium and neon; and / or, the flow rate of the first inert gas is 50 to 200 sccm, for example, 50 sccm, 70 sccm, 90 sccm, 100 sccm, 120 sccm, 140 sccm, 160 sccm, 180 sccm, 200 sccm, etc.; And / or, the halogen gas includes at least one of chlorine gas and bromine gas; and / or, the flow rate of the halogen gas is 0.5 to 5 sccm, for example, 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.; In a specific embodiment, the first inert gas is helium with a flow rate of 50 sccm, and the halogen gas is chlorine with a flow rate of 1.0 sccm.

[0036] In another specific embodiment, the first inert gas is neon gas with a flow rate of 160 sccm, and the halogen gas is bromine gas with a flow rate of 4.0 sccm.

[0037] Further, in step S2, the first radio frequency power P1 is 100-1000W, for example, 100W, 200W, 300W, 400W, 500W, 600W, 700W, 800W, 900W, 1000W, etc.; and / or, the reaction pressure of the chamber is 4.5 to 22 mTorr, for example, 4.5 mTorr, 10 mTorr, 15 mTorr, 20 mTorr, 22 mTorr, etc.; And / or, the first time T1 is 5 to 10 minutes, for example, it can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.

[0038] In a specific embodiment, the first RF power P1 is 100 W, the chamber reaction pressure is 10 mTorr, and the first time T1 is 6 min.

[0039] In another specific embodiment, the first RF power P1 is 500 W, the chamber reaction pressure is 20 mTorr, and the first time T1 is 8 min.

[0040] Further, in step S3, the second inert gas includes at least one of xenon and krypton; And / or, the flow rate of the second inert gas is 20-60 sccm, for example, 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, etc.

[0041] In a specific embodiment, the second inert gas is xenon gas with a flow rate of 20 sccm.

[0042] In another specific embodiment, the second inert gas is krypton gas with a flow rate of 50 sccm.

[0043] Further, in step S3, the second radio frequency power P2 is 1000-10000W, for example, 1000W, 2000W, 3000W, 4000W, 5000W, 6000W, 7000W, 8000W, 9000W, 10000W, etc.; and / or, the reaction pressure of the chamber is 1.4-4.2 mTorr, for example, 1.4 mTorr, 2.0 mTorr, 2.5 mTorr, 3.0 mTorr, 3.5 mTorr, 4.0 mTorr, 4.2 mTorr, etc.; And / or, the second time T2 is 5 to 10 minutes, for example, it can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, etc.

[0044] In a 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.

[0045] 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.

[0046] Further, in step S4, the third inert gas includes argon; And / or, the flow rate of the third inert gas is 20-60 sccm, for example, 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, etc.

[0047] Further, in step S4, the third radio frequency power P3 is 3000-10000W, for example, 3000W, 4000W, 5000W, 6000W, 7000W, 8000W, 9000W, 10000W, etc.; and / or, the reaction pressure of the chamber is 1.4-4.2 mTorr, for example, 1.4 mTorr, 2.0 mTorr, 2.5 mTorr, 3.0 mTorr, 3.5 mTorr, 4.0 mTorr, 4.2 mTorr, etc.; And / or, the third time T3 is 1 to 5 minutes, for example, it can be 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, etc.

[0048] In a specific embodiment, the third RF power P3 is 4000 W, the cavity reaction pressure is 2 mTorr, and the third time T3 is 2 min.

[0049] In another specific embodiment, the third RF power P3 is 6000 W, the chamber reaction pressure is 3 mTorr, and the third time T3 is 5 min.

[0050] In the following specific examples, the operations involved, if the conditions are not specified, are all carried out under conventional conditions or the conditions recommended by the manufacturer. All raw materials, if the manufacturers and specifications are not specified, are conventional products that can be obtained through commercial purchase. Example 1

[0051] A physical vapor deposition method for improving step coverage comprises the following steps: Step S1, pre-sputtering: select a titanium target with a target diameter of 320 mm, set the distance between the target and the wafer to 250 mm, set the substrate temperature to 200 °C, and the chamber vacuum to 4.0 × 10 -8 Torr, pre-sputtering power is 3000W, and pre-sputtering target material is 1min; Step S2, preparing a metal halide film layer TiCl X : A helium gas with a flow rate of 50 sccm and a chlorine gas with a flow rate of 1.5 sccm were introduced into the magnetron sputtering chamber, the chamber reaction pressure was set to 4.5 mTorr, the first RF power was set to 200 W, and the sputtering was performed for 5 minutes to form a metal halide film layer TiCl on the surface of the target. X ; Step S3, removing the metal halide film layer TiCl X : Xe gas with a flow rate of 30 sccm was introduced into the magnetron sputtering chamber, the chamber reaction pressure was set to 2.0 mTorr, the second RF power was 3000 W, and sputtering was performed for 5 minutes to remove the metal halide film layer TiCl X , a rough target surface is obtained; Step S4, sputtering a metal film: introducing argon gas with a flow rate of 30 sccm into the magnetron sputtering chamber, setting the chamber reaction pressure to 2.0 mTorr, the third RF power to 9000 W, and sputtering for 1.5 minutes to obtain a metal titanium film. Example 2

[0052] A physical vapor deposition method for improving step coverage comprises the following steps: Step S1, pre-sputtering: select a titanium target with a target diameter of 320 mm, set the distance between the target and the wafer to 250 mm, set the substrate temperature to 200 °C, and the chamber vacuum to 1.0 × 10 -8 Torr, pre-sputtering power is 3000W, and pre-sputtering target material is 1min; Step S2, preparing a metal halide film layer TiCl X : Helium with a flow rate of 100 sccm and chlorine with a flow rate of 3.5 sccm were introduced into the magnetron sputtering chamber, the chamber reaction pressure was set to 10 mTorr, the first RF power was 500 W, and the sputtering was performed for 5 minutes to form a metal halide film layer TiCl on the surface of the target. X ; Step S3, removing the metal halide film layer TiCl X : Xe gas with a flow rate of 50 sccm was introduced into the magnetron sputtering chamber, the chamber reaction pressure was set to 3.0 mTorr, the second RF power was 5000 W, and the sputtering was performed for 8 minutes to remove the metal halide film layer TiCl X , a rough target surface is obtained; Step S4, sputtering a metal film: introducing argon gas with a flow rate of 40 sccm into the magnetron sputtering chamber, setting the chamber reaction pressure to 3.0 mTorr, the third RF power to 9000 W, and sputtering for 3.5 minutes to obtain a metal titanium film. Example 3

[0053] A physical vapor deposition method for improving step coverage comprises the following steps: Step S1, pre-sputtering: select a titanium target with a target diameter of 320 mm, set the distance between the target and the wafer to 250 mm, set the substrate temperature to 200 °C, and the chamber vacuum to 4.0 × 10 -8Torr, pre-sputtering power is 3000W, and pre-sputtering target material is 1min; Step S2, preparing a metal halide film layer TiCl X : A helium gas with a flow rate of 50 sccm and a chlorine gas with a flow rate of 1.5 sccm were introduced into the magnetron sputtering chamber, the chamber reaction pressure was set to 4.5 mTorr, the first RF power was set to 200 W, and the sputtering was performed for 5 minutes to form a metal halide film layer TiCl on the surface of the target. X ; Step S3, removing the metal halide film layer TiCl X : Xe gas with a flow rate of 30 sccm was introduced into the magnetron sputtering chamber, the chamber reaction pressure was set to 2.0 mTorr, the second RF power was 3000 W, and sputtering was performed for 5 minutes to remove the metal halide film layer TiCl X , a rough target surface is obtained; Step S4, sputtering a metal film: introducing argon gas with a flow rate of 30 sccm into the magnetron sputtering chamber, setting the chamber reaction pressure to 2.0 mTorr, the third RF power to 9000 W, and sputtering for 5 minutes to obtain a metal titanium film.

[0054] Comparative Example 1 A physical vapor deposition method comprises the following steps: Step S1, pre-sputtering: select a titanium target with a target diameter of 320 mm, a distance between the target and the wafer stage of 250 mm, set the substrate temperature to 200 °C, and the chamber vacuum to 4.0 × 10 -8 Torr, pre-sputtering power is 3000W, and pre-sputtering target material is 1min; Step S2, sputtering a metal film: introducing argon gas with a flow rate of 30 sccm into the magnetron sputtering chamber, setting the chamber reaction pressure to 2.0 mTorr and the target sputtering power to 9000 W, sputtering for 2 minutes to obtain a metal titanium film. Application Examples

[0055] The metal titanium thin film provided in the application example 1 and the comparative example 1 was tested. Specifically, the metal titanium thin film films prepared in the application example 1 and the comparative example 1 with the same area were selected as samples, and the step coverage of the samples was tested. The step coverage is shown in Table 1.

[0056] Step coverage: Observe the film thickness of the cross section of the micropore on the wafer surface under a scanning electron microscope, and measure the film thickness at the top plane, side wall, and bottom of the micropore. Figure 3As shown, the ratio of the film thickness at the sidewall to the top plane and the ratio of the film thickness at the bottom to the top plane are calculated respectively, which is the step coverage, where the film thickness at the sidewall is the average of the film thickness on both sides of the sidewall. The testing instrument for the scanning electron microscope (SEM) is Hitachi S-4800.

[0057] Table 1 Step coverage of metal films in Example 1 and Comparative Example 1

[0058] From Table 1, Figure 4 and Figure 5 It can be seen that the step coverage of the metal titanium film obtained by the conventional physical vapor deposition method used in Comparative Example 1 is low, there is almost no film deposition in the middle and lower parts of the sidewalls, and the bottom coverage is less than 25%. However, under the physical vapor deposition method for improving the step coverage used in Example 1 of the present application, the step coverage is significantly improved, the sidewalls are continuous, the coverage at the lowest point exceeds 15%, and the bottom coverage exceeds 50%, indicating 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 toward Figure 1 The supercosine distribution shown is closer, which can improve the step coverage.

[0059] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A physical vapor deposition method for improving step coverage, characterized in that: First, a first inert gas and a halogen gas are introduced into the magnetron sputtering chamber to form a metal halide film layer on the target surface; secondly, a second inert gas is introduced into the magnetron sputtering chamber to remove the metal halide film layer to obtain a rough target surface; finally, a metal film is sputtered.

2. The physical vapor deposition method for improving step coverage as claimed in claim 1, characterized in that: 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 chamber vacuum to a preset vacuum, and pre-sputtering the target material at a preset power; Step S2, preparing a metal halide film layer: introducing the first inert gas into the magnetron sputtering chamber, applying a first radio frequency power P1 to the target material, and introducing the halogen gas into the chamber at the same time, sputtering for a first time T1, and forming a metal halide film layer on the surface of the target material; Step S3, removing the metal halide film layer: introducing a second inert gas into the magnetron sputtering chamber, applying a second radio frequency power P2 to the target material, and sputtering for a second time T2 to remove the metal halide film layer to obtain a rough target surface, marked as W2=P2*T2, where the multiple of W2 is X, and X is a positive integer; Step S4, sputtering the metal film: introducing a third inert gas into the magnetron sputtering chamber, applying a third radio frequency power P3 to the target material, sputtering for a third time T3, marked W3= P3*T3, the number of sputtering is N, N is a positive integer; When NW3<XW2, step S4 is implemented to obtain a metal film; When NW3>XW2, step S2, step S3, and step S4 are sequentially performed to obtain a metal thin film.

3. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: The relative atomic mass of the second noble gas is greater than the relative atomic mass of the first noble gas; and / or, the relative atomic mass of the third noble gas is greater than the relative atomic mass of the first noble gas; And / or, the relative atomic mass of the second noble gas is greater than or equal to the relative atomic mass of the third noble gas.

4. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: In step S1, the target material includes at least one of titanium, copper, aluminum, aluminum alloy, tantalum, nickel, silver, gold, and platinum; and / or, the target material has a diameter of 320 to 321 mm, 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, and aluminum nitride; And / or, the distance between the target and the wafer is 150-450 mm; And / or, the preset temperature is 25 to 300 ℃; And / or, the preset vacuum degree is 5.0×10 -8 Torr or less; And / or, the preset power of pre-sputtering is 3000W.

5. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: In step S2, the first inert gas includes at least one of helium and neon; and / or, the flow rate of the first inert gas is 50 to 200 sccm; And / or, the halogen gas includes at least one of chlorine gas and bromine gas; And / or, the flow rate of the halogen gas is 0.5-5 sccm.

6. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: In step S2, the first radio frequency power P1 is 100-1000W; and / or, the chamber reaction pressure is 4.5 to 22 mTorr; And / or, the first time T1 is 5 to 10 minutes.

7. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: In step S3, the second inert gas includes at least one of xenon and krypton; And / or, the flow rate of the second inert gas is 20-60 sccm.

8. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: In step S3, the second radio frequency power P2 is 1000-10000W; and / or, the chamber reaction pressure is 1.4 to 4.2 mTorr; And / or, the second time T2 is 5 to 10 minutes.

9. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: In step S4, the third inert gas includes argon; And / or, the flow rate of the third inert gas is 20-60 sccm.

10. The physical vapor deposition method for improving step coverage as claimed in claim 2, characterized in that: In step S4, the third radio frequency power P3 is 3000-10000W; and / or, the chamber reaction pressure is 1.4 to 4.2 mTorr; And / or, the third time T3 is 1 to 5 minutes.

Images