Method for improving magnetron sputtering efficiency of composite current collector and magnetron sputtering device

Abstract

The invention provides a method for improving the magnetron sputtering efficiency of a composite current collector. The method comprises the following steps: (c) setting and maintaining the distance between the sputtering surface of a sputtering target material and the to-be-coated surface of a composite current collector base film within a preset optimal distance range, and carrying out sputtering coating; wherein the optimal distance range is 0.8-1.5 times of the diameter of the cathode dark area of the sputtering target material. According to the method, sputter coating is carried out by setting and maintaining the distance between the sputtering surface of the sputtering target material and the surface to be coated of the composite current collector base film within the preset optimal distance range, and the optimal distance range is 0.8-1.5 times of the diameter of the cathode dark area of the sputtering target material; and the utilization rate of the target material in the preparation process of the composite current collector can be greatly improved, so that the sheet resistance of the composite current collector can be reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a method for improving magnetron sputtering efficiency of composite current collector. BACKGROUND

[0002] The magnetron sputtering vacuum coating device includes a target material, and during the operation of the magnetron sputtering vacuum coating device, the material on the target material is sputtered onto the composite current collector to form the composite current collector. However, the sputtering efficiency of the target material in the existing magnetron sputtering vacuum coating device for manufacturing the composite current collector is low. SUMMARY

[0003] In view of the deficiencies of the prior art, the purpose of the present application is to provide a method for improving the magnetron sputtering efficiency of the composite current collector, so as to solve the technical problem of low sputtering efficiency of the target material in the magnetron sputtering vacuum coating device for the composite current collector mentioned in the background.

[0004] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: A method for improving the magnetron sputtering efficiency of the composite current collector, comprising the following steps: (a) providing a magnetron sputtering device, the device comprising a vacuum chamber, a sputtering target material, and a base film carrying device; (b) installing the composite current collector base film to be coated on the base film carrying device; (c) setting and maintaining the distance between the sputtering surface of the sputtering target material and the surface to be coated of the composite current collector base film within a pre-set optimal distance range for sputtering coating; wherein the pre-set optimal distance range is 8 to 20 times the diameter of the sputtering target material cathode dark area.

[0005] Further, the pre-set optimal distance range is 10 to 20 times the diameter of the sputtering target material cathode dark area.

[0006] Further, the sputtering target material is a single metal target material such as a copper target or an aluminum target, or an alloy target material.

[0007] Further, the composite current collector base film is a high molecular polymer film, preferably a polyethylene terephthalate, polypropylene, polyimide or polyethylene naphthalate film.

[0008] Further, the working gas pressure range of the sputtering process is 0.1 Pa to 1 Pa.

[0009] Further, the coating process is vacuum magnetron sputtering or evaporation, and the base vacuum degree is ≤5×10⁻³ Pa.

[0010] Further, during the sputtering process, the target-to-base distance is monitored in real time, and the target-to-base distance is dynamically adjusted according to the monitoring result to maintain it within the pre-set optimal distance range.

[0011] In another aspect, the present application provides a magnetron sputtering device, comprising: a vacuum chamber; a sputtering target material installed in the vacuum chamber; a substrate film carrying device for carrying a composite current collector substrate film, installed in the vacuum chamber, and arranged opposite to the sputtering target material; a target-substrate distance adjusting mechanism for precisely adjusting and maintaining the distance between the sputtering surface of the sputtering target material and the surface to be plated of the substrate film on the substrate film carrying device; and a control unit configured to control the target-substrate distance adjusting mechanism so that the distance is maintained within a preset optimal distance range, which is 8 to 20 times the diameter of the cathode dark space of the sputtering target material.

[0012] Further, the target-substrate distance adjusting mechanism comprises: a precision lead screw guide mechanism, a servo motor driven lifting platform, or a piezoelectric ceramic micro displacement driver; and / or a distance sensor for measuring the target-substrate distance in real time and feeding back the measurement signal to the control unit.

[0013] Further, the control unit calculates or calls the pre-stored cathode dark space diameter and corresponding optimal distance range according to the input process parameters.

[0014] Compared with the prior art, the method for improving the magnetron sputtering efficiency of a composite current collector according to the present application comprises the following steps: (c) setting and maintaining the distance between the sputtering surface of the sputtering target material and the surface to be plated of the composite current collector substrate film within a preset optimal distance range for sputtering plating; wherein the preset optimal distance range is 8 to 20 times the diameter of the cathode dark space of the sputtering target material. By the above method, since the distance between the sputtering surface of the sputtering target material and the surface to be plated of the composite current collector substrate film is set and maintained within a preset optimal distance range, and the preset optimal distance range is 8 to 20 times the diameter of the cathode dark space of the sputtering target material, the utilization rate of the target material during the preparation of the composite current collector can be greatly improved, and thus the sheet resistance of the composite current collector can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A preparation process flow chart of the method for improving the magnetron sputtering efficiency of a composite current collector according to the present application is provided. DETAILED DESCRIPTION

[0016] To make the purpose, technical solutions and effects of the present application clearer and more explicit, the present application is further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0017] It is to be understood that when a part is referred to as being "on" or "connected to" another part, it can be directly on or connected to the other part, or there can be intervening parts present.

[0018] It should also be noted that the left, right, up, down and other orientation terms in the embodiments of the present application are only relative concepts or are referenced to the normal use state of the product, and should not be considered as limiting.

[0019] When the composite current collector is plated by the magnetron sputtering plating equipment, the material on the target material needs to be sputtered onto the composite current collector or the composite current collector base film to form a sputtered metal layer on the composite current collector or the composite current collector base film, but the inventor found in the production process that the existing magnetron sputtering plating device has the phenomenon of low sputtering efficiency of the target material, therefore, the inventor made a lot of experiments and proposed a method for improving the magnetron sputtering efficiency of the composite current collector, comprising the following steps: (a) providing a magnetron sputtering equipment, the equipment comprising a vacuum chamber, a sputtering target material, a base film bearing device; the purpose of step (a) is to prepare for magnetron sputtering on the composite current collector base film or the composite current collector, the vacuum chamber can be a vacuum chamber for magnetron sputtering, and the selection of the sputtering target material is determined according to the type of the composite current collector produced, such as producing a composite copper current collector, the target material can be a copper target material or a copper alloy target material. And the base film bearing device is mainly a winding system composed of a roller, a tension roller and the like in the production of the composite current collector. The above devices are all known devices.

[0020] Further, the method for improving the magnetron sputtering efficiency of the composite current collector further comprises step (b), which is to install the composite current collector base film to be plated on the base film bearing device, and in actual production, the installation of the composite current collector base film on the base film bearing device will introduce the composite current collector base film into the roller in the magnetron sputtering plating equipment through the process of film introduction, which can be introduced by a film introduction device or manually.

[0021] Further, the method for improving the efficiency of magnetron sputtering of the composite current collector further comprises step (c) of setting and maintaining the distance d between the sputtering surface of the sputtering target and the surface to be plated of the composite current collector substrate within a preset optimal distance range for sputtering plating; wherein the preset optimal distance range is 8 to 20 times the diameter of the cathode dark space of the sputtering target. In the present application, in the glow discharge plasma of magnetron sputtering, there is a special area, the cathode dark space, next to the cathode or the surface of the sputtering target, which has the following characteristics: after the electrons are emitted from the cathode or accelerated by the electric field, the flight distance in this area is short, and the energy is not enough to excite or ionize the gas atoms, so it hardly emits light. At the same time, the positively charged gas ions are accelerated by the strong electric field in this area, and bombard the cathode target surface to cause sputtering. The diameter of the cathode dark space refers to the thickness of the cathode dark space, that is, the distance from the target surface to the negative glow boundary. The optimal distance range of 8 to 20 times the diameter of the cathode dark space of the sputtering target can significantly improve the deposition rate, because in this range, the flight distance of the sputtered particles is moderate. The probability of particle collision and scattering is reduced, and the energy loss is small. At the same time, the number of particles reaching the substrate is large. Compared with the distance d between the sputtering surface of the sputtering target and the surface to be plated of the composite current collector substrate < 8λ or d > 20λ, the deposited metal film thickness per unit time is significantly increased, directly improving the production efficiency and reducing the energy consumption per unit area. Moreover, the preset optimal distance range is 8 to 20 times the diameter of the cathode dark space of the sputtering target. It can also bring the following effects: improve the film thickness uniformity, and at this distance, the spatial distribution of sputtered particles on the substrate surface is wider and the angular distribution is more reasonable. If the distance is too close, the particle flow is too concentrated, resulting in thick center and thin edge. And if the distance is too far, the particle flow is too divergent and the density is low, and the uniformity is also poor. Wherein, λ refers to the diameter of the cathode dark space of the sputtering target.

[0022] Preferably, in the method for improving the efficiency of magnetron sputtering of the composite current collector, the working pressure range of the sputtering process is 0.1 Pa to 1 Pa. And the plating process is vacuum magnetron sputtering or evaporation, and the background vacuum degree is ≤5×10⁻³Pa. This is conducive to improving the efficiency of magnetron sputtering and the quality of plating.

[0023] Preferably, the preset optimal distance range d is 10 to 20 times of the diameter λ of the cathode dark space of the sputtering target material. In this range, the sheet resistance of the composite current collector can be greatly reduced, and the film coating efficiency can be improved. This is because in the range of 10λ~20λ, the base film is just at the peak density boundary of the negative glow region, the probability of capturing sputtering particles is maximum, and the thermal radiation intensity decays to the safety threshold of the base film, which can also protect the composite current collector base film from being damaged by high temperature. Specifically, the diameter of the cathode dark space of the target material is 10mm-15mm, which can be 10mm, 11mm, 12mm, 13mm, 14mm or 15mm.

[0024] Further, the composite current collector base film is a high polymer film, preferably a polyethylene terephthalate, polypropylene, polyimide or polyethylene naphthalate film. These films are light in weight and each has its own advantages, and are known materials. Specifically, the thickness of the high polymer film is 3um-8um.

[0025] Further, during sputtering, the target-substrate distance d is monitored in real time, and the target-substrate distance d is dynamically adjusted according to the monitoring result to maintain it within the preset optimal distance range. In this way, in actual production, the thickness fluctuation of the metal layer plated on the composite current collector base film can be reduced, and the consistency of the surface sheet resistance of the composite current collector can be maintained.

[0026] On the other hand, the present application provides a magnetron sputtering device, comprising: a vacuum chamber; a sputtering target material installed in the vacuum chamber; that is, the magnetron sputtering target material is installed in the vacuum chamber, and a base film carrying device is also provided in the vacuum chamber, the base film carrying device is used to carry the composite current collector base film, and is installed in the vacuum chamber and arranged opposite to the sputtering target material; the base film carrying device at least includes a cooling main drum, so that the composite current collector base film can be cooled when magnetron sputtering is performed.

[0027] Further, the magnetron sputtering device further comprises a target-substrate distance adjusting mechanism for accurately adjusting and maintaining the distance d between the sputtering surface of the sputtering target material and the surface to be plated of the base film on the base film carrying device, so that the distance between the surface to be plated and the target material can be adjusted in real time, the efficiency can be improved, and the film plating uniformity can be improved.

[0028] Further, the magnetron sputtering device further comprises a control unit configured to control the target-substrate distance adjusting mechanism to maintain the distance d within a preset optimal distance range of 8 to 20 times the diameter λ of the dark space of the sputtering target cathode. The control unit can be controlled online to avoid manual operation. Specifically, the control unit comprises a laser range finder and a capacitive sensor, and outputs signals to a servo motor after detecting information. Thus, the distance between the composite current collector base film and the target material is controlled.

[0029] Further, the target-substrate distance adjusting mechanism comprises a precision lead screw guide mechanism, which is specifically responsible for converting the rotary motion of the motor into linear displacement to drive the precision movement of the sputtering target or the roller carrying the base film. The specific working process of the precision lead screw guide mechanism is as follows: after the control unit issues a displacement instruction, the servo motor rotates by a specific angle, then the lead screw rotates to push the target or the roller carrying the base film to slide along the guide rail, and finally the target-substrate distance d is accurately adjusted to millimeter level.

[0030] Further, the target-substrate distance adjusting mechanism further comprises a servo motor driven lifting platform or a piezoelectric ceramic micro displacement driver, and / or a distance sensor for real-time measurement of the target-substrate distance d and feedback of the measurement signal to the control unit. The servo motor driven lifting platform mainly provides controllable rotary power with high torque and low speed. The specific cooperative working process is as follows: the control unit calculates the target displacement amount, then converts it into the required rotation angle of the motor, the servo driver outputs current to drive the motor, and the encoder real-time feedbacks the actual rotation angle, and finally the error is dynamically corrected until the positioning is accurate. The piezoelectric ceramic micro displacement driver mainly realizes sub-micron level displacement compensation by using piezoelectric effect. The distance sensor is mainly used for real-time measurement of the target-substrate distance. The main working process is as follows: the sensor measures the target substrate in real time, the sensor transmits signals to the control unit, the control unit compares with the set target value, and then generates an error signal to drive the adjusting mechanism. Embodiment 1

[0031] Preparation of composite copper current collector: PP film was used as the base film of the composite current collector, then a copper target with a thickness of 12 mm was used, under the conditions of a working gas pressure of 0.5 Pa and a background vacuum degree of 5x10-3 Pa, the PP film walking speed was 2 m / min, the power was 60 KW, the target thickness of copper sputtered on the composite current collector base film was 100 nm, and the distance between the copper target and the composite current collector base film was 96 mm. After sputtering, the average thickness of the copper metal layer at the left and right 10 cm of the middle of the composite current collector base film in the width direction was detected, and the metal layer thickness was measured by XRF. It was found that the average thickness of copper in this area was 100 nm, and the copper metal layer thickness at a distance of 10 cm from the left and right edges of the composite current collector width direction was 98 nm. Overall, it was uniform. Example 2

[0032] Preparation of composite copper current collector: PP film was used as the base film of the composite current collector, then a copper target with a thickness of 12 mm was used, under the conditions of a working gas pressure of 0.5 Pa and a background vacuum degree of 5x10-3 Pa, the PP film walking speed was 2 m / min, the power was 60 KW, the target thickness of copper sputtered on the composite current collector base film was 100 nm, and the distance between the copper target and the composite current collector base film was 96 mm. After sputtering, the average thickness of the copper metal layer at the left and right 10 cm of the middle of the composite current collector base film in the width direction was detected, and the metal layer thickness was measured by XRF. It was found that the average thickness of copper in this area was 100 nm, and the copper metal layer thickness at a distance of 10 cm from the left and right edges of the composite current collector width direction was 98 nm. Overall, it was uniform.

[0033] Comparative Example 1 Preparation of comparative composite copper current collector: PP film was used as the base film of the composite current collector, then a copper target with a thickness of 12 mm was used, under the conditions of a working gas pressure of 0.5 Pa and a background vacuum degree of 5x10-3 Pa, the PP film walking speed was 2 m / min, the power was 60 KW, the target thickness of copper sputtered on the composite current collector base film was 100 nm, and the distance between the copper target and the composite current collector base film was 96 mm. After sputtering, the average thickness of the copper metal layer at the left and right 10 cm of the middle of the composite current collector base film in the width direction was detected, and the metal layer thickness was measured by XRF. It was found that the average thickness of copper in this area was 100 nm, and the copper metal layer thickness at a distance of 10 cm from the left and right edges of the composite current collector width direction was 98 nm. Overall, it was uniform.

[0034] Comparative Example 2 Preparation of comparative composite copper current collector: The PP film is used as the base film of the composite current collector, then the copper target with a thickness of 12 mm is used, the working pressure is 0.5 Pa, the base vacuum degree is 5*10-3 Pa, the PP film walking speed is 2 m / min, the power is 60 KW, the copper target thickness is 100 nm on the composite current collector base film, the distance between the copper target and the composite current collector base film is 95 mm, after sputtering, the average thickness of the copper in the middle line of the composite current collector base film is detected, and it is found that the average thickness of the copper in this area is 110 nm, and the thickness of the copper metal layer at the position 10 cm away from the left and right edges of the composite current collector width direction is 90 nm.

[0035] Comparative example 3 The PP film is used as the base film of the composite current collector, then the copper target with a thickness of 12 mm is used, the working pressure is 0.5 Pa, the base vacuum degree is 5*10-3 Pa, the PP film walking speed is 2 m / min, the power is 60 KW, the copper target thickness is 100 nm on the composite current collector base film, the distance between the copper target and the composite current collector base film is 241 mm, after sputtering, the average thickness of the copper in the middle line of the composite current collector base film is detected, and it is found that the average thickness of the copper in this area is 60 nm, and the thickness of the copper metal layer at the position 10 cm away from the left and right edges of the composite current collector width direction is 30 nm.

[0036] In summary, the method for improving the magnetron sputtering efficiency of the composite current collector comprises the following steps: (c) setting and maintaining the distance d between the sputtering surface of the sputtering target and the surface to be plated of the composite current collector base film within the preset optimal distance range for sputtering plating; wherein the preset optimal distance range is 8 to 20 times the diameter of the cathode dark area of the sputtering target. Through the above method, since the distance d between the sputtering surface of the sputtering target and the surface to be plated of the composite current collector base film is set and maintained within the preset optimal distance range for sputtering plating, and the preset optimal distance range is 8 to 20 times the diameter of the cathode dark area of the sputtering target, the utilization rate of the target material during the preparation of the composite current collector can be greatly improved, and in turn the sheet resistance of the composite current collector can be reduced.

[0037] It can be understood that, for those skilled in the art, equivalent replacements or changes can be made according to the technical solutions and the inventive concept of the present application, and all these changes or replacements shall belong to the protection scope of the claims appended to the present application.

Claims

1. A method for improving the efficiency of a magnetron sputtering of a composite current collector, the method comprising: The method comprises the following steps: (a) providing a magnetron sputtering device, which comprises a vacuum chamber, a sputtering target, and a substrate film bearing device; (b) mounting a composite current collector substrate film to be coated on the substrate film bearing device; (c) setting and maintaining the distance between the sputtering surface of the sputtering target and the surface to be coated of the composite current collector substrate film; (d) performing sputter coating within a preset optimal distance range; wherein the preset optimal distance range is 8 to 20 times the diameter of the cathode dark space of the sputtering target.

2. The method of improving the magnetron sputtering efficiency of a composite current collector of claim 1, wherein, The preset optimal distance range is 10 to 20 times the diameter of the cathode dark space of the sputtering target.

3. The method of improving the magnetron sputtering efficiency of a composite current collector of claim 1, wherein, The sputtering target is a single metal target or an alloy target, such as a copper target or an aluminum target.

4. The method of improving the magnetron sputtering efficiency of a composite current collector of claim 1, wherein, The composite current collector substrate film is a high polymer film, preferably a polyethylene terephthalate, polypropylene, polyimide, or polyethylene naphthalate film.

5. The method of improving the magnetron sputtering efficiency of a composite current collector of claim 1, wherein The working pressure of the sputtering process ranges from 0.1 Pa to 1 Pa.

6. The method of improving the magnetron sputtering efficiency of a composite current collector of claim 1, wherein, The coating process is vacuum magnetron sputtering or evaporation, and the base vacuum degree is ≤5×10⁻³ Pa.

7. The method of improving the magnetron sputtering efficiency of a composite current collector of claim 1, wherein, During the sputtering process, the target-substrate distance is monitored in real time, and the target-substrate distance is dynamically adjusted based on the monitoring results to maintain it within the preset optimal distance range.

8. A magnetron sputter device for carrying out the method according to any one of claims 1 to 7, characterized in that It comprises: a vacuum chamber; a sputtering target installed in the vacuum chamber; a substrate film bearing device for bearing a composite current collector substrate film, which is installed in the vacuum chamber and arranged opposite to the sputtering target; a target-substrate distance adjusting mechanism for accurately adjusting and maintaining the distance between the sputtering surface of the sputtering target and the surface to be coated of the substrate film on the substrate film bearing device; and a control unit configured to control the target-substrate distance adjusting mechanism to maintain the distance within a preset optimal distance range, which is 8 to 20 times the diameter of the cathode dark space of the sputtering target.

9. The magnetron sputtering device of claim 8, wherein, The target-substrate distance adjusting mechanism comprises a precision lead screw guide mechanism, a servo motor driven lifting platform, or a piezoelectric ceramic micro displacement driver; and / or a distance sensor for measuring the target-substrate distance in real time and feeding back the measurement signal to the control unit.

10. The apparatus of claim 9, wherein, The control unit calculates or calls the pre-stored cathode dark space diameter and corresponding optimal distance range according to the input process parameters.

Images