PVD double-magnetron completely synchronous and asynchronous rotating device and method for preparing metal thin film

Abstract

The application provides a PVD double-magnetron completely synchronous and asynchronous rotating device and a metal thin film preparation method. The device comprises a sealed cavity, an upper magnetron and a lower magnetron are arranged in the sealed cavity, the upper magnetron is arranged above a target material, the lower magnetron is arranged below the target material, a wafer carrier and a heater are arranged between the target material and the lower magnetron, the upper magnetron and the lower magnetron can rotate in the same direction or in the opposite direction, the upper magnetron and the lower magnetron are used for dynamically controlling the ionization rate and the incident angle distribution of metal atoms from the target material, the magnetic field of the upper magnetron and the lower magnetron is non-uniformly distributed in the radial direction of the target material, and the magnetic field intensity is non-linearly attenuated in the axial direction. The application enhances the magnetic field intensity in the transition area by coupling and superimposing the magnetic field, guides the motion track and distribution of electrons and ions in the plasma, dynamically controls the ionization rate of metal atoms and the incident angle distribution of metal ions, adjusts the magnetic field intensity gradient, accurately suppresses the emission of large-angle particles, and improves the step coverage of the metal thin film.

Description

Technical Field

[0001] This invention relates to a magnetron sputtering apparatus, specifically to a PVD dual magnetron fully synchronous and asynchronous rotation device and a method for preparing metal thin films. Background Technology

[0002] Magnetron sputtering is a type of physical vapor deposition (PVD) generally used to prepare materials such as metals, semiconductors, and insulators. It has advantages such as simple equipment, ease of control, large coating area, and strong adhesion, and is therefore widely used in microelectronics and optoelectronics. Magnetron sputtering is a collision process between incident particles and the target. Incident particles undergo complex scattering and collisions with target atoms within the target, transferring some momentum to the target atoms. These target atoms then collide with other target atoms, forming a cascade process. In this cascade process, some target atoms near the surface gain sufficient momentum to move outwards, thus leaving the target and being sputtered. The sputtered target atoms land on the wafer, achieving the coating on the wafer.

[0003] In magnetron sputtering, when depositing films on wafers with microporous structures, in order to improve the filling rate of the micropores, it is generally considered to ionize the metal target atoms. Then, under the action of negative bias voltage, the angle between the incident direction of metal ions and the normal direction is smaller, so as to achieve deposition and film formation on the bottom and sidewalls of the micropores.

[0004] Existing technologies include using a collimator to filter out metal atoms at large angles, installed between the target and the wafer. Large-angle metal atoms or ions sputtered down will hit the collimator, while vertical and small-angle metal atoms or ions can be sputtered onto the wafer surface, thereby improving overall step coverage. However, this approach excessively sacrifices atomic sputtering yield, resulting in a very low deposition rate. Furthermore, during the commissioning phase, repeated trials at different locations are required to find the optimal installation scheme, which is time-consuming and labor-intensive, impacting both work efficiency and increasing costs. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a PVD dual magnetron fully synchronous and asynchronous rotation device and a method for preparing metal thin films. This invention significantly enhances the magnetic field strength in the transition region by coupling and superimposing magnetic fields in the middle region of the cavity (i.e., between the target and the wafer, which can be called the transition region). This guides the trajectory and distribution of electrons and ions in the plasma, thereby dynamically controlling the ionization rate of metal atoms and the incident angle distribution of metal ions. Combined with magnetic field strength gradient adjustment, it precisely suppresses large-angle particle emission, increases the vertical particle flux ratio, and improves the step coverage of the metal thin film.

[0006] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows: In a first aspect, embodiments of the present invention provide a PVD dual magnetron fully synchronous and asynchronous rotation device, including a sealed cavity, an upper magnetron and a lower magnetron disposed within the sealed cavity, the upper magnetron being disposed above the target material, the lower magnetron being disposed below the target material, and a wafer stage and a heater being disposed between the target material and the lower magnetron. The upper and lower magnetrons can rotate in the same or opposite directions to dynamically control the ionization rate and incident angle distribution of metal atoms from the target material. The magnetic fields of the upper and lower magnetrons are non-uniformly distributed in the radial direction of the target material, and the magnetic field strength is non-linearly decaying in the axial direction of the target material.

[0007] Furthermore, the upper magnetor and / or lower magnetor includes a counterweight and a groove, which are detachably disposed at both ends of the first surface of the first mounting plate. The two are movable relative to the first mounting plate to accommodate the size of the target material and / or the sealing cavity.

[0008] Furthermore, the groove includes an inner ring groove and an outer ring groove. The outer ring groove is disposed on the outer periphery of the inner ring groove. An inner ring magnetic post is embedded in the inner ring groove, and an outer ring magnetic post is embedded in the outer ring groove. The inner ring magnetic post is the N pole, and the outer ring magnetic post is the S pole.

[0009] Furthermore, a rotating shaft is also provided on the second surface of the first mounting plate; The rotating shaft is driven by a motor, and / or the rotating shaft is connected to a rotating platform, which drives the rotating shaft to rotate.

[0010] Furthermore, the inner and outer magnetic pillars are arranged in a closed area enclosed by the base plate, the cover plate, and the second mounting plate, and the cover plate is a magnetically conductive plate.

[0011] Furthermore, the central axes of the sealed cavity, wafer stage, target material, upper magnetron and lower magnetron coincide, and the upper magnetron and lower magnetron rotate around the central axis; The distance between the lower surface of the upper magnetron and the upper surface of the target is 1-5 mm, and the distance between the upper surface of the lower magnetron and the lower surface of the wafer is 40-50 mm.

[0012] Furthermore, a dynamic bias modulation module is also provided in the sealed cavity for superimposing radio frequency bias voltages with a frequency of 2-13.56MHz and a power of 0-1000W on the wafer stage.

[0013] In a second aspect, embodiments of the present invention provide a method for preparing a metal thin film, performed on the PVD dual magnetron fully synchronous and asynchronous rotating device described in the first aspect, comprising the following steps: Step S1: Place the wafer on the wafer stage of the PVD dual magnetron fully synchronous and asynchronous rotation device, and set the rotation speed and phase offset angle θ of the upper and lower magnetrons. Step S2: Set the temperature of the wafer stage to 25-300℃, and maintain the vacuum level of the sealed cavity at 5.0×10⁻⁶. - 8 For Torr and below, the argon gas flow rate is 20-60 sccm, the reaction pressure in the sealed cavity is 1.4-4.2 mTorr, and the target material is pre-sputtered; Step S3: Transfer the wafer to the sealed cavity, maintain the argon flow rate at 20-60 sccm, the sealed cavity pressure at 1.4-4.2 mTorr, set the sputtering power of the target material to 3000-20000 W, the bias power to 0-1000 W, and the sputtering time to 1-5 min, to obtain a titanium thin film.

[0014] Furthermore, the distance between the target material and the wafer stage is 150-450 mm.

[0015] Furthermore, the rotational speeds ω1 of the upper magnetron and ω2 of the lower magnetron satisfy the following conditions: 0 ≤ |Δω| = ||ω1| - |ω2|| ≤ 50 rpm, and the phase offset angle θ is controlled within 0°–270°.

[0016] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows: This invention significantly enhances the magnetic field strength in the transition region by coupling and superimposing a magnetic field in the middle region of the cavity (i.e., between the target and the wafer, which can be called the transition region), guiding the movement trajectory and distribution of electrons and ions in the plasma, thereby dynamically controlling the ionization rate of metal atoms and the incident angle distribution of metal ions; combined with the adjustment of the magnetic field strength gradient, it precisely suppresses the emission of large-angle particles, increases the proportion of vertical particle flux, and improves the step coverage of the metal thin film. Attached Figure Description

[0017] Figure 1 These are film measurement points used to observe the distribution of film thickness within micropores or trenches of a substrate under a scanning electron microscope. Figure 1 As shown.

[0018] Figure 2 This describes the step coverage of the metal thin film obtained in Example 1 of this invention.

[0019] Figure 3 This describes the step coverage of the metal thin film obtained in Example 4 of the present invention.

[0020] Figure 4 This describes the step coverage of the metal thin film obtained in Example 6 of the present invention.

[0021] Figure 5 This is the step coverage of the metal thin film in the comparative example of the present invention.

[0022] Figure 6 This is a schematic diagram of the internal structure of the sealed cavity of the PVD dual magnetron fully synchronous and asynchronous rotation device.

[0023] Figure 7 This is a structural diagram of the upper magnetron and / or lower magnetron.

[0024] Figure 8 This is a partial structural diagram of the upper magnetron and / or lower magnetron.

[0025] Explanation of reference numerals in the attached drawings: 1-Sealed cavity; 2-Upper magnetron; 3-Lower magnetron; 4-Target material; 5-Wafer stage; 6-Heater; 7-Air inlet; 81-Inner ring magnetic column; 82-Outer ring magnetic column; 9-Base plate; 10-Cover plate; 11-Second mounting plate; 12-Thin film measurement point; 13-Wafer; 14-Metal thin film; 15-Rotating platform; 231-Counterweight; 232-Inner ring groove; 233-Outer ring groove; 234-First mounting plate; 235-Rotating shaft. Detailed Implementation

[0026] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention.

[0027] like Figure 6 As shown, this embodiment of the invention provides a PVD dual magnetron fully synchronous and asynchronous rotation device, including a sealed cavity 1. An upper magnetron 2 and a lower magnetron 3 are disposed in the sealed cavity 1. The upper magnetron 2 is disposed above the target material 4, with a distance of 1-5 mm between it and the upper surface of the target material 4. The lower magnetron 3 is disposed below the target material 4. A wafer stage 5 and a heater 6 are disposed between the target material 4 and the lower magnetron 3. The distance between the lower magnetron 3 and the wafer 13 is 40-50 mm. The heater is used to heat the wafer stage 5, thereby indirectly heating the wafer 13 placed on the wafer stage 5.

[0028] The upper magnetron 2 and the lower magnetron 3 can rotate in the same or opposite directions to dynamically control the ionization rate and incident angle distribution of metal atoms from the target material 4. The magnetic fields of the upper magnetron 2 and the lower magnetron 3 are non-uniformly distributed in the radial direction of the target material 4, and the magnetic field strength is non-linearly decaying in the axial direction of the target material 4.

[0029] like Figure 7-8 As shown, both the upper magnetic controller 2 and the lower magnetic controller 3 include a counterweight 231 and a groove. The groove includes an inner ring groove 232 and an outer ring groove 233. The outer ring groove 233 is disposed on the outer periphery of the inner ring groove 232. The counterweight 231 and the groove are respectively disposed at both ends of the first mounting plate 234. The inner ring groove 232 is embedded with an inner ring magnetic column 81, and the outer ring groove 233 is embedded with an outer ring magnetic column 82. The inner ring magnetic column 81 is the N pole, and the outer ring magnetic column 82 is the S pole. The arrangement of the inner ring magnetic column 81 and the outer ring magnetic column 82 makes the magnetic field of the upper magnetron 2 and the lower magnetron 3 non-uniformly distributed in the radial direction, and the magnetic field strength is non-linearly decaying along the axial direction.

[0030] To verify the characteristics of the magnetic field gradient of the upper magnetron 2 and the lower magnetron 3 being non-uniformly distributed along the radial direction of the target material 4 and non-linearly decaying along the axial direction, the magnetic field distribution and magnetic field strength of the upper magnetron 2 and the lower magnetron 3 when they are in a static state were tested.

[0031] During testing, a Hall-Gauss meter was used to measure the magnetic field, with a measurement accuracy of ±5% and a range of 0-25000 Gs. During the test, the plasma was not ignited, no process gas was introduced, and both the upper magnetron 2 and the lower magnetron 3 remained stationary. A coordinate system was established with the central axis of the target 4 as the reference, with the radial direction (r) defined as the direction along the radius of the target 4 and the axial direction (z) defined as the direction from the target 4 towards the wafer 13. The test conditions were: target 4 diameter 320 mm, distance between target 4 and wafer stage 5 250 mm, distance between upper magnetron 2 and the upper surface of target 4 2 mm, and distance between lower magnetron 3 and wafer 13 50 mm. Test points were selected at a plane 0.5 mm below the target surface, a plane 0.5 mm above the wafer, and the midpoint of the transition zone between target 4 and wafer 13, with the midpoint of the transition zone located at z=125 mm. During the test, the sensitive direction of the gaussmeter probe was arranged along the axial direction z, and the axial magnetic field strength component Bz at each test point was measured. Each test point was repeated 3 times, and the average value was taken as the final result. Table 1 shows the test results of the radial magnetic field distribution in the corresponding action area when the upper magnetron 2 and the lower magnetron 3 are in a stationary state.

[0032] Table 1. Radial magnetic field distribution (Bz, Gs) of the upper and lower magnetrons in a stationary state.

[0033] As shown in Table 1, when the upper and lower magnetrons are in a stationary state, whether they are 0.5 mm below the target surface or 0.5 mm above the wafer, the magnetic fields of the upper magnetron 2 and the lower magnetron 3 are non-uniformly distributed in the radial direction.

[0034] Table 2. Test results of the planar magnetic field strength in the middle of the transition zone (Bz, Gs)

[0035] As shown in Table 2, when the dual magnetrons are stationary, a stable axial magnetic field strength can still be measured in the central plane of the transition region between the target 4 and the wafer 13, and this magnetic field is also non-uniformly distributed radially. The magnetic field formed by the upper magnetron 2 and the lower magnetron 3 is not limited to the vicinity of the target surface or the wafer, but extends to the transition region between the target 4 and the wafer 13, forming a composite magnetic field distribution in this region. This composite magnetic field provides the basis for the dynamic magnetic field control of the upper magnetron 2 and the lower magnetron 3 in the rotating state, the guidance of the trajectory of electrons and metal ions in the plasma, and the enhancement of vertical transport of metal ions.

[0036] The counterweight 231 and the groove are detachably disposed on the first surface of the first mounting plate 234, and the two are movable relative to the first mounting plate 234 to accommodate the size of the target material 4 and / or the sealing cavity 1.

[0037] A rotating shaft 235 is also provided on the second surface of the first mounting plate 234; in a preferred embodiment, the rotating shaft 235 is disposed between the counterweight 231 and the groove. The rotating shaft 235 is driven by a motor; and / or the rotating shaft 235 is connected to a rotating platform 15, and the rotating platform 15 drives the rotating shaft 235 to rotate.

[0038] In one embodiment, the rotating shaft 235 of the upper magnetron 2 is driven by a motor, which is located outside the sealed cavity 1. The rotating shaft 235 of the lower magnetron 3 is connected to a rotating platform 15, and the rotating platform 15 drives the rotating shaft 235 to rotate.

[0039] In one implementation, the inner magnetic column 81 and the outer magnetic column 82 are arranged in a closed area enclosed by the base plate 9, the cover plate 10 and the second mounting plate 11, and the cover plate 10 is a magnetic plate.

[0040] An air inlet 7 is provided on the side of the sealed cavity 1 for introducing process gas.

[0041] The sealed cavity 1 is also equipped with a dynamic bias modulation module, which is used to superimpose an RF bias voltage with a frequency of 2-13.56MHz and a power of 0-1000W on the wafer stage 5, thereby increasing the longitudinal acceleration energy of the incident metal ions on the wafer 13 and compressing the half-width angle of the incident metal ion incident angle distribution.

[0042] The target material 4 is connected to the negative high-voltage cathode, and the sealed cavity 1 and the wafer 13 are grounded as the anode.

[0043] This invention provides a method for preparing a metal thin film, comprising the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the above-mentioned PVD dual magnetron fully synchronous and asynchronous rotation device, and set the rotation speed and phase offset angle θ of the upper magnetron 2 and the lower magnetron 3. Step S2: Set the substrate temperature to 25-300℃, and maintain the vacuum degree of the sealed cavity at 5.0×10⁻⁶. -8 For Torr and below, the argon gas flow rate is 20-60 sccm, the reaction pressure in the sealed chamber is 1.4-4.2 mTorr, and the target material is pre-sputtered; Step S3: Transfer wafer 13 to a DC magnetron sputtering vacuum sealed chamber, maintain an argon flow rate of 20-60 sccm, a sealed chamber pressure of 1.4-4.2 mTorr, set the sputtering power of target 4 to 3000-20000 W, the bias power to 0-1000 W, and the sputtering time to 1-5 min to obtain a titanium thin film. Measure the thickness of the thin film in the micropores or trenches of wafer 13, as shown in the measurement points. Figure 1 As shown, the step coverage of the metal thin film is obtained. The step coverage is defined as the ratio of the bottom film thickness to the film thickness at the top plane.

[0044] The distance between the target 4 and the wafer stage 5 is 150-450 mm.

[0045] The rotational speed ω1 of the upper magnetron 2 and the rotational speed ω2 of the lower magnetron 3 satisfy the following conditions: 0≤|Δω|=||ω1|-|ω2||≤50 rpm, and the phase offset angle θ is controlled within 0°–270°.

[0046] Preferably, the rotational speed ω1 and rotational speed ω2 of the lower magnetron 3 satisfy the following condition: |ω2|>|ω1|.

[0047] The diameter of the target 4 is 300-350 mm, and the distance between the target 4 and the wafer stage 5 is 150-450 mm.

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Example 1

[0049] A method for preparing a metal thin film includes the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the above-mentioned PVD dual magnetron fully synchronous and asynchronous rotation device. The rotation speed ω1 of the upper magnetron 2 is set to 50 rpm and the rotation direction is counterclockwise. The rotation speed ω2 of the lower magnetron 3 is set to 50 rpm and the rotation direction is clockwise. That is, |Δω|=||ω1|-|ω2||=|50-50|=0. The phase offset angle between the upper magnetron 2 and the lower magnetron 3 is 0°. Step S2: Set the temperature of the wafer stage 5 to 25°C, and maintain the vacuum level of the sealed cavity 1 at 5.0 × 10⁻⁶. − 8 Torr, argon gas with a flow rate of 30 sccm is introduced through the air inlet 7, the reaction pressure of the sealed cavity 1 is 2.0 mTorr, and the target material 4 is pre-sputtered for 1 min under the above-mentioned rotating state using a sputtering power of 3000 W. Step S3: Transfer wafer 13 to the DC magnetron sputtering vacuum sealed chamber 1, maintain argon flow rate of 30 sccm, chamber pressure of 2.0 mTorr, set target sputtering power to 12000 W, and use a dynamic bias modulation module to superimpose an RF bias of 13.56 MHz and 300 W on the wafer stage 5. Sputtering time is 1.5 min, resulting in a titanium thin film with a step coverage of 70%. Figure 2 As shown.

[0050] Based on the SJI-SEMI Depommerits P188 Pro PVD equipment, the target 4 is a titanium target with a purity of 99.999%, the diameter of the target 4 is 320 mm, and the distance between the target 4 and the wafer stage 5 is 250 mm.

[0051] The distance between the upper magnetron 2 and the upper surface of the target 4 is 2mm, and the distance between the lower magnetron 3 and the wafer 13 is 50mm. Example 2

[0052] A method for preparing a metal thin film includes the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the above-mentioned PVD dual magnetron fully synchronous and asynchronous rotation device. The rotation speed of the upper magnetron 2 is set to 50 rpm and rotates counterclockwise, and the rotation speed of the lower magnetron 3 is set to 100 rpm and rotates clockwise. That is, the difference between the rotation speed ω1 of the upper magnetron 2 and the rotation speed ω2 of the lower magnetron 3 is |Δω|=||ω1|-|ω2||=|50-100|=50 rpm, and the phase offset angle between the upper magnetron 2 and the lower magnetron 3 is 0°. Step S2: Set the temperature of the wafer stage 5 to 25°C, and maintain the vacuum level of the sealed cavity 1 at 5.0 × 10⁻⁶. − 8Torr, argon gas with a flow rate of 30 sccm is introduced through the air inlet 7, the reaction pressure of the sealed cavity 1 is 2.0 mTorr, and the target material is pre-sputtered for 1 min under the above-mentioned rotating state using a sputtering power of 3000 W. Step S3: Transfer wafer 13 to a DC magnetron sputtering vacuum sealed chamber, maintain argon flow rate of 30 sccm, sealed chamber pressure of 2.0 mTorr, set target sputtering power to 12000 W, and superimpose an RF bias voltage of 13.56MHz and 300W on wafer stage 5. Sputtering time is 1.5 min to obtain a titanium thin film with a step coverage of 80%.

[0053] Using SJI-SEMI's Depomerits P188 Pro PVD equipment, a titanium target with a purity of 99.999% was selected, with a target diameter of 320 mm and a distance of 250 mm between the target and the wafer stage 5.

[0054] The distance between the upper magnetron 2 and the upper surface of the target 4 is 2mm, and the distance between the lower magnetron 3 and the wafer 13 is 50mm. Example 3

[0055] A method for preparing a metal thin film includes the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the above-mentioned PVD dual magnetron fully synchronous and asynchronous rotation device. The rotation speed ω1 of the upper magnetron 2 is set to 100 rpm and rotates counterclockwise, and the rotation speed ω2 of the lower magnetron 3 is set to 50 rpm and rotates clockwise. That is, the difference between the rotation speed ω1 of the upper magnetron 2 and the rotation speed ω2 of the lower magnetron 3 is |Δω|=||ω1|-|ω2||=|50-100|=50 rpm, and the phase offset angle between the upper magnetron 2 and the lower magnetron 3 is 0°. Step S2: Set the temperature of the wafer stage 5 to 25°C, and maintain the vacuum level of the sealed cavity 1 at 5.0 × 10⁻⁶. − 8 Torr, argon gas with a flow rate of 30 sccm is introduced through the air inlet 7, the reaction pressure in the sealed cavity is 2.0 mTorr, and the target material 4 is pre-sputtered for 1 min under the above-mentioned rotating state using a sputtering power of 3000 W. Step S3: Transfer wafer 13 to a DC magnetron sputtering vacuum sealed chamber, maintain argon flow rate of 30 sccm, sealed chamber pressure of 2.0 mTorr, set target sputtering power to 12000 W, and superimpose an RF bias voltage of 13.56MHz and 300W on wafer stage 5. Sputtering time is 1.5 min to obtain a titanium thin film with a step coverage of 78%.

[0056] Based on the SJI-SEMI Depommerits P188 Pro PVD equipment, a titanium target with a purity of 99.999% was selected, with a target diameter of 320 mm and a distance of 250 mm between the target and the wafer stage.

[0057] The distance between the upper magnetron 2 and the upper surface of the target 4 is 2mm, and the distance between the lower magnetron 3 and the wafer 13 is 50mm. Example 4

[0058] A method for preparing a metal thin film includes the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the above-mentioned PVD dual magnetron fully synchronous and asynchronous rotation device. The rotation speed ω1 of the upper magnetron 2 is set to 100 rpm and rotates counterclockwise, and the rotation speed ω2 of the lower magnetron 3 is set to 100 rpm and rotates clockwise, that is, |Δω|=||ω1|-|ω2||=|100-100|=0, and the phase offset angle between the upper magnetron 2 and the lower magnetron 3 is 0°. Step S2: Set the temperature of the wafer stage 5 to 25°C, and maintain the vacuum level of the sealed cavity at 5.0 × 10⁻⁶. −8 Torr, argon gas with a flow rate of 30 sccm is introduced through the air inlet 7, the reaction pressure of the sealed cavity 1 is 2.0 mTorr, and the target material is pre-sputtered for 1 min under the above-mentioned rotating state using a sputtering power of 3000 W. Step S3: Transfer wafer 13 to a DC magnetron sputtering vacuum sealed chamber, maintain an argon flow rate of 30 sccm, a sealed chamber pressure of 2.0 mTorr, set the target sputtering power to 12000W, and superimpose an RF bias of 13.56MHz and 300W on wafer stage 5. Sputtering time is 1.5 min, resulting in a titanium thin film. The step coverage is 88%. Figure 3 As shown.

[0059] Based on the SJI-SEMI Depommerits P188 Pro PVD equipment, a titanium target with a purity of 99.999% was selected, with a target diameter of 320 mm and a distance of 250 mm between the target and the wafer stage 5.

[0060] The distance between the upper magnetron 2 and the upper surface of the target 4 is 2mm, and the distance between the lower magnetron 3 and the wafer 13 is 50mm. Example 5

[0061] A method for preparing a metal thin film includes the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the above-mentioned PVD dual magnetron fully synchronous and asynchronous rotation device. The rotation speed ω1 of the upper magnetron 2 is set to 100 rpm and rotates counterclockwise. The rotation speed ω2 of the lower magnetron 3 is set to 100 rpm and rotates counterclockwise. That is, |Δω|=||ω1|-|ω2||=|100-100|=0. The phase offset angle between the upper magnetron 2 and the lower magnetron 3 is 0°. Step S2: Set the temperature of the wafer stage 5 to 25°C, and maintain the vacuum level of the sealed cavity at 5.0 × 10⁻⁶. −8 Torr, argon gas with a flow rate of 30 sccm is introduced through the air inlet 7, the reaction pressure in the sealed cavity is 2.0 mTorr, and the target material 4 is pre-sputtered for 1 min under the above-mentioned rotating state using a sputtering power of 3000 W. Step S3: Transfer wafer 13 to a DC magnetron sputtering vacuum sealed chamber, maintain argon flow rate of 30 sccm, sealed chamber pressure of 2.0 mTorr, set target sputtering power to 12000 W, and superimpose an RF bias voltage of 13.56MHz and 300W on wafer stage 5. Sputtering time is 1.5 min to obtain a titanium thin film with a step coverage of 76%.

[0062] Based on the SJI-SEMI Depommerits P188 Pro PVD equipment, a titanium target with a purity of 99.999% was selected, with a target diameter of 320 mm and a distance of 250 mm between the target and the wafer stage 5.

[0063] The distance between the upper magnetron 2 and the upper surface of the target 4 is 2mm, and the distance between the lower magnetron 3 and the wafer 13 is 50mm. Example 6

[0064] A method for preparing a metal thin film includes the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the above-mentioned PVD dual magnetron fully synchronous and asynchronous rotation device. The rotation speed ω1 of the upper magnetron 2 is set to 100 rpm and rotates counterclockwise, and the rotation speed ω2 of the lower magnetron 3 is set to 100 rpm and rotates clockwise, that is, |Δω|=||ω1|-|ω2||=|100-100|=0, and the phase offset angle is 90°. Step S2: Set the temperature of the wafer stage 5 to 25°C, and maintain the vacuum level of the sealed cavity at 5.0 × 10⁻⁶. −8 Torr, argon gas with a flow rate of 30 sccm is introduced through the air inlet 7, the reaction pressure in the sealed cavity is 2.0 mTorr, and the target material is pre-sputtered for 1 min under the above-mentioned rotating state using a sputtering power of 3000 W. Step S3: Transfer wafer 13 to a DC magnetron sputtering vacuum sealed chamber, maintain an argon flow rate of 30 sccm, a sealed chamber pressure of 2.0 mTorr, set the target sputtering power to 12000 W, and superimpose an RF bias of 13.56 MHz and 300 W on wafer stage 5. Sputtering time is 1.5 min, resulting in a titanium thin film with a step coverage of 92%. Figure 4 As shown.

[0065] Based on the SJI-SEMI Depommerits P188 Pro PVD equipment, a titanium target with a purity of 99.999% was selected, with a target diameter of 320 mm and a distance of 250 mm between the target and the wafer stage 5.

[0066] The distance between the upper magnetron 2 and the upper surface of the target 4 is 2mm, and the distance between the lower magnetron 3 and the wafer 13 is 50mm.

[0067] Comparative Example A method for preparing a metal thin film includes the following steps: Step S1: Place the wafer 13 on the wafer stage 5 of the PVD dual magnetron fully synchronous and asynchronous rotation device. Set the rotation speed ω1 of the upper magnetron 2 to 100 rpm and rotate counterclockwise, and set the rotation speed ω2 of the lower magnetron 3 to 0 rpm; that is, |Δω|=||ω1|-|ω2||=|100-0|=100 rpm; Step S2: Set the temperature of the wafer stage 5 to 25°C, and maintain the vacuum level of the sealed cavity at 5.0 × 10⁻⁶. −8 Torr, argon gas flow rate of 30 sccm, reaction pressure in sealed chamber of 2.0 mTorr, and pre-sputtering target material with sputtering power of 3000 W for 1 min; Step S3: Transfer wafer 13 to a DC magnetron sputtering vacuum sealed chamber, maintain an argon flow rate of 30 sccm, a sealed chamber pressure of 2.0 mTorr, set the target sputtering power to 12000 W, and superimpose an RF bias of 13.56 MHz and 300 W on wafer stage 5. Sputtering time is 1.5 min, resulting in a titanium thin film. The step coverage is 45%. Figure 5 As shown.

[0068] Based on the SJI-SEMI Depommerits P188 Pro PVD equipment, a titanium target with a purity of 99.999% was selected, with a target diameter of 320 mm and a distance of 250 mm between the target and the wafer stage 5.

[0069] The distance between the upper magnetron 2 and the upper surface of the target 4 is 2mm, and the distance between the lower magnetron 3 and the wafer 13 is 50mm.

[0070] The distribution of film thickness within micropores or trenches of a substrate is observed under a scanning electron microscope. Film measurement points are shown below. Figure 1 As shown. Step coverage is defined as the ratio of the film thickness at the bottom to the film thickness at the top plane. The step coverage of the wafer in Example 1 is shown below. Figure 2 Example 4: Wafer step coverage is shown in [reference needed]. Figure 3 The step coverage in Example 6 is shown below. Figure 4 See the comparative step coverage. Figure 5 The calculated step coverage is shown in Table 3.

[0071] Table 3. Step coverage of the metal thin film in Examples 1-6 and the comparative example.

[0072] As shown in Table 3, the bottom coverage is closely related to the coordinated rotation state of the dual magnetrons. Compared with the comparative example using only the upper magnetron, this invention, by setting a lower magnetron and having the upper and lower magnetrons rotate in tandem, enables the target surface magnetic field and the wafer surface magnetic field to form a dynamic coupling superposition in the transition region between the target and the wafer, thereby enhancing the vertical transport capability of metal ions and significantly improving the bottom coverage.

[0073] Specifically, under the condition of opposite rotation of the dual magnetrons, increasing the rotation speed of the upper magnetron 2 and the lower magnetron 3 can enhance the dynamic control capability of the composite magnetic field in the transition region, increasing the bottom coverage from 70% in Example 1 to 88% in Example 4. Under the condition of rotation speed difference, Example 2, with a higher rotation speed of the lower magnetron 3, has a slightly higher bottom coverage than Example 3, with a higher rotation speed of the upper magnetron, indicating that the control of the incident ion direction by the wafer-side magnetic field is more conducive to bottom deposition. Under the same rotation speed of 100 rpm, Example 4 with opposite rotation is significantly better than Example 5 with co-rotation, indicating that opposite rotation can form a stronger composite magnetic field coupling effect. Furthermore, according to Examples 4 and 6, Example 6, with a 90° phase shift on the basis of 100 rpm opposite rotation, achieves the highest bottom coverage of 92%, indicating that an appropriate phase shift can further optimize the spatiotemporal distribution of the composite magnetic field and increase the proportion of metal ions vertically incident.

[0074] Therefore, the improved bottom coverage in this invention mainly stems from the compression of the metal ion incident angle and the enhanced vertical transport effect of the dynamic composite magnetic field formed by the upper and lower dual magnetrons. Overall, the bottom coverage follows these rules: dual magnetrons are superior to single magnetrons, opposite-direction rotation is superior to same-direction rotation, high-speed rotation is superior to low-speed rotation, and appropriate phase shift can further improve bottom coverage performance.

[0075] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A PVD dual-magnetic-controlled, fully synchronous and asynchronous rotation device, characterized in that, The device includes a sealed cavity (1), in which an upper magnetron (2) and a lower magnetron (3) are provided. The upper magnetron (2) is located above the target material (4), and the lower magnetron (3) is located below the target material (4). A wafer stage (5) and a heater (6) are provided between the target material (4) and the lower magnetron (3). The upper magnetron (2) and the lower magnetron (3) can rotate in the same or opposite directions to dynamically control the ionization rate and incident angle distribution of metal atoms from the target material (4). The magnetic fields of the upper magnetron (2) and the lower magnetron (3) are non-uniformly distributed in the radial direction of the target material (4), and the magnetic field strength is non-linearly decaying in the axial direction of the target material (4).

2. The PVD dual magnetron fully synchronous and asynchronous rotation device according to claim 1, characterized in that, The upper magnetor (2) and / or lower magnetor (3) include a counterweight (231) and a groove, which are detachably disposed at both ends of the first surface of the first mounting plate (234). They are movable relative to the first mounting plate (234) to accommodate the size of the target material (4) and / or the sealing cavity (1).

3. The PVD dual magnetron fully synchronous and asynchronous rotation device according to claim 2, characterized in that, The groove includes an inner ring groove (232) and an outer ring groove (233). The outer ring groove (233) is disposed on the outer periphery of the inner ring groove (232). An inner ring magnetic post (81) is embedded in the inner ring groove (232), and an outer ring magnetic post (82) is embedded in the outer ring groove (233). The inner ring magnetic post (81) is the N pole, and the outer ring magnetic post (82) is the S pole.

4. The PVD dual magnetron fully synchronous and asynchronous rotation device according to claim 2, characterized in that, A rotating shaft (235) is also provided on the second surface of the first mounting plate (234); The rotating shaft (235) is driven by a motor, and / or the rotating shaft (235) is connected to a rotating platform (15), and the rotating platform (15) drives the rotating shaft (235) to rotate.

5. The PVD dual magnetron fully synchronous and asynchronous rotation device according to claim 3, characterized in that, The inner magnetic column (81) and the outer magnetic column (82) are arranged in a closed area enclosed by the base plate (9), the cover plate (10) and the second mounting plate (11), and the cover plate (10) is a magnetic plate.

6. The PVD dual magnetron fully synchronous and asynchronous rotation device according to claim 1, characterized in that, The central axes of the sealed cavity (1), wafer stage (5), target material (4), upper magnetron (2) and lower magnetron (3) coincide, and the upper magnetron (2) and lower magnetron (3) rotate around the central axis; The distance between the lower surface of the upper magnetron (2) and the upper surface of the target (4) is 1-5 mm, and the distance between the upper surface of the lower magnetron (3) and the lower surface of the wafer (13) is 40-50 mm.

7. The PVD dual magnetron fully synchronous and asynchronous rotation device according to any one of claims 1-6, characterized in that, The sealed cavity (1) is also equipped with a dynamic bias modulation module, which is used to superimpose an RF bias voltage with a frequency of 2-13.56MHz and a power of 0-1000W on the wafer stage (5).

8. A method for preparing a metal thin film, characterized in that, Performed on the PVD dual magnetron fully synchronous and asynchronous rotating device according to any one of claims 1-7, including the following steps: Step S1: Place the wafer (13) on the wafer stage (5) of the PVD dual magnetron fully synchronous and asynchronous rotation device, and set the rotation speed and phase offset angle θ of the upper magnetron (2) and the lower magnetron (3); Step S2: Set the temperature of the wafer stage (5) to 25-300℃, and maintain the vacuum level of the sealed cavity (1) at 5.0×10⁻⁶. -8 Torr and below, the argon gas flow rate is 20-60 sccm, the reaction pressure of the sealed cavity (1) is 1.4-4.2 mTorr, and the target material (4) is pre-sputtered; Step S3: Transfer the wafer (13) to the sealed cavity (1), maintain the argon flow rate at 20-60 sccm, the sealed cavity pressure at 1.4-4.2 mTorr, set the sputtering power of the target material (4) to 3000-20000 W, the bias power to 0-1000 W, and the sputtering time to 1-5 min, and obtain a titanium thin film.

9. The method for preparing a metal thin film according to claim 8, characterized in that, The distance between the target (4) and the wafer stage (5) is 150-450 mm.

10. The method for preparing a metal thin film according to claim 8, characterized in that, The rotational speed ω1 of the upper magnetron (2) and the rotational speed ω2 of the lower magnetron (3) satisfy the following conditions: 0≤|Δω|=||ω1|-|ω2||≤50 rpm, and the phase offset angle θ is controlled within 0°–270°.

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