Double-sided efficient CVD (chemical vapor deposition) continuous coating system and method for thin metal strip

Abstract

The invention provides a double-sided efficient CVD continuous coating system and method for a thin metal strip, and relates to the technical field of thin film preparation, the main structure of the coating system is that a positive electrode group and a negative electrode group are arranged between two winding discs, and a thin film deposition area is arranged between the positive electrode group and the negative electrode group; the upper clamping electrode and the lower clamping electrode of each pair of clamping electrodes in the positive electrode group and the negative electrode group are in electric contact with the edges of the upper surface and the lower surface of the metal thin strip; the radio-frequency current source is connected to at least one pair of radio-frequency electrodes which are oppositely arranged on the two sides of the substrate channel, the two CVD precursor spray heads are arranged above and below the substrate channel in the thin film deposition area, and the two anti-deposition protection pieces are arranged on the two sides of the substrate channel between the positive electrode group and the negative electrode group and located between the radio-frequency electrodes. According to the invention, Joule heat generated by stable current provided by the electrified self-heating device of the metal thin strip is used for rapidly reaching the temperature required by coating, so that the utilization rate of precursor particles on the surface of the metal thin strip can be improved, and the coating rate is improved while the film forming quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film preparation, and in particular to a metal thin strip double-sided high-efficiency CVD continuous coating system and method. Background Art

[0002] The application of thin film technology is very extensive, covering many fields such as optics, electronics, medicine, energy, etc. Therefore, the efficient preparation of high-quality thin films is of great significance for scientific research and industrial applications.

[0003] Chemical vapor deposition (CVD) refers to the process of introducing vapor containing film-forming element precursors and other gases required for the reaction into a reaction chamber, and chemical reactions occur on the substrate surface to form a thin film. It is easier to form an industrial technology because the film-forming material components can be composed in any proportion, the film formation rate is fast, the uniformity is good, and large-area film preparation can be achieved. In the preparation of CVD thin films, deposition temperature is one of the key factors affecting the quality of the film. Changes in deposition temperature will not only cause changes in the growth rate and morphology of the film, but also affect the crystallinity and structural integrity of the film. Therefore, it is necessary to select a suitable deposition temperature during the film growth process to ensure the stability of the film structure and quality.

[0004] At present, the main heating methods for preparing thin films are heat conduction heating, induction heating, radiation heating, and self-heating by electricity. Heat conduction heating usually involves passing a large current through a heating wire with a large resistance, which will generate a large amount of Joule heat in a short time and then transfer the heat to the substrate. The advantage is that the principle is simple and the application environment is relatively wide; the disadvantage is that the temperature rises slowly, the energy consumption is high, and the heating of large-area and large-volume substrates is uneven. Induction heating usually involves placing a conductor in a high-frequency magnetic field to generate an induced current in the conductor, which is then heated by the current. The advantage is that the heating temperature is high and the heating rate is fast; the disadvantage is that the substrate has high requirements and must be a conductor with a regular shape and uniform resistivity distribution. At the same time, the high-frequency magnetic field will also affect the equipment, and equipment protection is also a problem that needs to be solved. Radiative heating is to place the substrate in the radiation range of a high-temperature heating element for heating. The advantage is that the temperature rises quickly and the requirements for the substrate material are low. However, this heating method has strict requirements on the spatial distribution and quantity of the heating element and the substrate. Continuous film deposition may adhere to the heating element or the radiation transmission area, resulting in uneven temperature distribution. The above-mentioned heating forms are all heat transfer or heat conversion, while energized self-heating is to evenly distribute the heating current to the substrate and directly heat it by generating Joule heat through the substrate itself. For narrow, long and continuous metal flexible substrates, in order to ensure the continuous deposition of thin films on them, the substrate is usually taken up in a winding device. In the process of industrialization, the substrate is often required to have a faster running speed. Therefore, a heating system that can still achieve rapid temperature rise and fall, large-area substrate heating, uniform temperature distribution on the heating surface, and good repeatability during fast running is more important for the controlled growth and efficient deposition of thin films on metal substrates. Energized self-heating has a simple structure, fast temperature rise and fall, and high energy efficiency, and is more suitable for thin metal strips.

[0005] Plasma-assisted coating is a film-forming technology widely used in the fields of solar cells, optical industry, etc. The so-called plasma is the application of energy to gases, raw material precursors, etc., so that they are partially dissociated into free electrons, ions, free radical particles, etc., and these particle mixtures are plasma. Usually, the plasma-assisted coating device is composed of a radio frequency current source combined with two electrode plates. The area between the two electrode plates is a plasma excitation zone. During the coating process, plasma is formed in this area and the energy is significantly increased, the activity of the reaction gas is increased, the number of clustered particles is reduced, the film quality is improved, and the deposition rate is increased.

[0006] At present, there are related patents (such as CN 108977791 B) that use the self-heating method of power supply to heat the metal strip, but this type of design still has several problems in practical application. The electrode sheets are placed on the side of the metal strip, and the current is transmitted by the contact between the electrode sheet and the side of the metal strip. The electrode sheet and the side of the metal strip are in linear contact. During the long-term belt running process, the metal strip constantly cuts and wears the same position of the electrode sheet, which leads to poor contact between the electrode sheet and the metal strip. The small contact area of ​​linear contact is also prone to sparking, which affects the continuous preparation of the film on the metal strip. When facing metal strips of different widths, thicknesses, and bending strengths, since the pressure between the electrode sheet and the metal strip cannot be adjusted, some metal strips will be deformed or bent, affecting the later coating. In the continuous coating process, as the thickness of the film increases, the energy obtained by the subsequent deposited particles from the heated metal strip changes. The deposited particles do not have enough energy and cannot form a high-quality film, which not only affects the film forming efficiency, but also leads to problems with the final film forming quality and uniformity.

[0007] In addition, CVD thin film preparation is a process in which vaporized particles undergo chemical reactions on a substrate to form a film, which will inevitably be carried away by the gas phase transport system, resulting in precursor waste. Therefore, how to increase precursor utilization, reduce coating cycles, improve coating efficiency, reduce costs, and efficiently prepare CVD thin films is an issue that needs to be addressed urgently. Summary of the invention

[0008] Based on the above problems, the purpose of the present invention is to provide a metal thin band double-sided high-efficiency CVD continuous coating system and method, which evenly distributes the heating current and introduces it into the metal thin strip substrate by means of self-heating through power-on, and directly heats it by generating Joule heat through the substrate itself, so as to solve the problems of poor contact and easy sparking caused by wear between the electrode sheet and the side of the metal thin strip during long-term continuous running of the metal thin strip, and the problem that metal thin strips of different widths, thicknesses and bending strengths are easily deformed or twisted due to side pressure; solve the problem that in the process of providing energy by power-on heating of the metal strip, the energy obtained from the heated metal strip changes with the increase of film thickness, and the deposited particles do not have enough energy to form a high-quality thin film, thereby affecting the efficient, continuous and stable coating on the metal strip; and also solve the problem that the precursor particles are not adsorbed on the surface of the metal strip to react and form a film and are carried away by the gas phase transmission system.

[0009] The technical solution adopted by the present invention to achieve its invention object is a metal thin-band double-sided high-efficiency CVD continuous coating system, characterized in that it includes a winding disk, a metal thin-band energized self-heating device, a plasma-assisted coating device, a CVD precursor shower head, and an anti-deposition protection member, wherein:

[0010] The specific structure of the metal strip energized self-heating device is as follows:

[0011] A positive electrode group and a negative electrode group are arranged between the two winding disks, and a thin film deposition area is formed between the positive electrode group and the negative electrode group; the metal thin strip wound on one winding disk passes through the positive electrode group, and after passing through the thin film deposition area, it is pulled to the negative electrode group by the winding disk on the other side; the movement path of the metal thin strip between the winding disks forms a substrate channel;

[0012] The positive electrode group includes a power interface, a current distribution circuit and at least two pairs of clamping electrodes. The upper and lower clamping electrodes of each pair of clamping electrodes are distributed on the upper and lower sides of the substrate channel and form electrical contact with the upper and lower surface edges of the metal strip. The winding disk can drive the metal strip to continuously move. Each clamping electrode is in constant contact with the metal strip and the metal strip can slide smoothly. The two pairs of clamping electrodes are electrically connected to each other and are electrically connected to the power interface through the current distribution circuit.

[0013] The structure of the negative electrode group is the same as that of the positive electrode group;

[0014] The positive electrode group and the negative electrode group are connected to an external direct current source through their respective power supply interfaces to form a complete path; the heating current provided by the direct current source is divided through the current distribution circuit of the positive electrode group and gradually introduced into the metal strip from the upper and lower surface edges of the metal strip, and the current is gradually led out and merged through the current distribution circuit of the negative electrode group to form a complete loop, relying on the Joule heat generated by the resistance of the metal strip itself to reach the temperature required for film growth;

[0015] The plasma assisted coating device is arranged in the thin film deposition area, and its specific structure is as follows:

[0016] The radio frequency current source is connected to at least one pair of first radio frequency electrodes and second radio frequency electrodes arranged on both sides of the substrate channel via a radio frequency circuit, and a plasma excitation region is formed between the first radio frequency electrode and the second radio frequency electrode; the plasma-assisted coating device forms plasma during the coating process to provide energy for film formation;

[0017] There are two CVD precursor shower heads, which are respectively arranged above and below the substrate channel in the thin film deposition area. The precursor particles are sprayed to the thin film deposition area by the CVD precursor shower heads. The spray outlet of the CVD precursor shower head is located in the plasma excitation area, which is conducive to more CVD precursors being adsorbed on the surface of the metal strip to reach the reaction activation energy, making it easy to form a film on the metal strip, thereby improving the utilization rate of the precursor.

[0018] There are two anti-deposition protection members, which are respectively arranged on both sides of the substrate channel between the positive electrode group and the negative electrode group and between the first RF electrode and the second RF electrode. The anti-deposition protection member is a horizontally arranged long strip, and its length is greater than the length of the thin film deposition area. A protection groove for protecting the edge of the metal strip is opened on the inner side of the anti-deposition protection member. The width of the protection groove is not less than the clamping width between the clamping electrode and the edge of the metal strip, and the height of the protection groove is greater than the thickness of the metal strip.

[0019] When the metal strip passes through the positive electrode group and enters the thin film deposition area, its edge is in the protection groove, and the precursor particles are blocked and cannot be sprayed onto the edge of the metal strip, so that the edge of the metal strip will not be deposited with a thin film, thereby ensuring that after the metal strip enters the negative electrode group, the clamping electrode of the negative electrode group can be electrically connected to the metal strip. If the edge of the metal strip is not protected at this time, a thin film will also be deposited on the edge of the metal strip in the thin film deposition area, and after the metal strip enters the negative electrode group, the clamping electrode of the negative electrode group will not be electrically connected to the metal strip.

[0020] Furthermore, the current distribution circuit is a series of shunt resistors, and each pair of clamping electrodes is respectively connected to a connection point of adjacent shunt resistors and two ends of the resistor string.

[0021] Furthermore, the shunt resistor is one of a wirewound resistor, a carbon film resistor, and a metal film resistor.

[0022] Furthermore, the specific structure of the positive electrode group is:

[0023] A first through groove along the direction of the substrate channel is opened in the middle of the placement plate made of insulating material, and at least two pairs of second through grooves are opened on both sides of the first through groove on the placement plate, and the second through grooves are perpendicular to the first through grooves, and upper and lower clamping electrodes are arranged in each pair of second through grooves, and the clamping electrodes are electrode sheets with grooves in the middle, wherein the groove opening of the upper electrode sheet is placed downward, and the groove opening of the lower electrode sheet is placed upward, and the grooves of the upper and lower electrode sheets are aligned; the groove is located in the first through groove and its direction is consistent with the first through groove, and the two side edges of the groove are at a set distance from the two side edges of the first through groove; the metal strip passes through the gap between the upper and lower electrode sheets and is confined in the first through groove of the placement plate, the central part of the metal strip is located within the range of the groove, and the upper and lower surface edges of the metal strip are respectively in electrical contact with the surfaces of the upper and lower electrode sheets located on both sides of the groove;

[0024] The bolt rod passes through the mounting holes on both sides of the mounting plate, the lower electrode sheet, and the upper electrode sheet in sequence from bottom to top, and the mounting plate and the two electrode sheets are mounted together. A nut is mounted on the bolt rod above the upper electrode sheet, and a spring sleeved on the bolt rod is mounted between the nut and the upper electrode sheet. In this way, the clamping force of the electrode sheet can be adjusted very conveniently, that is, the nut is adjusted to squeeze the spring, thereby applying pressure to the electrode sheet, ensuring that the surfaces of the electrode sheet on both sides of the groove clamp the upper and lower surface edges of the metal strip and have good mutual pressure, so that the metal strip can slide smoothly while having good electrical contact with the electrode sheet.

[0025] There are also positioning holes on both sides of the upper and lower electrode sheets, and the positioning rods on the mounting plate pass through the positioning holes; the positioning rods can realize the precise positioning of the clamped electrode sheets, ensuring a certain contact area between the clamped electrode sheets and the upper and lower surface edges of the metal strip, and preventing electrical disconnection due to component misalignment.

[0026] The structure of the negative electrode group is the same as that of the positive electrode group.

[0027] Furthermore, the material of the electrode sheet is one of Ag-W alloy, Ag-WC alloy and Ag-Cu alloy.

[0028] Furthermore, the distance between the spray outlet of the CVD precursor shower head and the surface of the metal strip is 0.5 to 1 cm.

[0029] Furthermore, the material of the placement plate is one of zirconium oxide ceramics, silicon oxide ceramics, boron nitride ceramics, and polytetrafluoroethylene insulation materials, and the anti-deposition protection member is made of a quartz plate.

[0030] Furthermore, the clamping electrode is a roller electrode or a rolling ball electrode, that is, the electrode is made into a roller shape or a sphere shape and can rotate around the wheel axis or the center of the sphere.

[0031] The use of fixed electrode sheets sometimes easily causes scratches on the surface of the metal strip. The roller-type electrode or the rolling ball-type electrode is in rolling contact with the surface of the metal strip, which can reduce the chance of scratches on the surface of the metal strip.

[0032] Furthermore, the clamping electrode is a track-type electrode, including a track and rollers inside the track.

[0033] In this way, while achieving rolling contact between the electrode and the surface of the metal strip, the contact area between the electrode and the surface of the metal strip can be increased and the contact resistance can be reduced.

[0034] The present invention also provides a method for coating using the above-mentioned metal thin-band wide-band double-sided high-efficiency CVD continuous coating system, comprising the following steps:

[0035] S1. Pass the metal strip between the upper and lower clamping electrodes of the positive electrode group, pull it to the negative electrode group after passing through the film deposition area, and then pass it out from between the upper and lower clamping electrodes of the negative electrode group; the upper and lower clamping electrodes are in good electrical contact with the upper and lower surface edges of the metal strip;

[0036] S2. The heating current provided by the DC current source is divided through the current distribution circuit of the positive electrode group and gradually introduced into the metal strip from the upper and lower surface edges of the metal strip. The current is then gradually led out and merged through the current distribution circuit of the negative electrode group to form a complete loop. The Joule heat generated by the resistance of the metal strip itself is used to reach the temperature required for film growth.

[0037] S3. Precursor particles are sprayed by a CVD precursor double spray head onto the middle area of ​​the upper and lower surfaces of the substrate channel in the thin film deposition area. At the same time, the upper and lower surface edges of the metal strip are shielded by anti-deposition protection. Plasma energy is introduced into the precursor particles between the first RF electrode and the second RF electrode of the plasma-assisted coating device. The precursor particles react in the middle area of ​​the upper and lower surfaces of the metal strip that is electrically heated to form a thin film.

[0038] The beneficial effects of the present invention are:

[0039] The clamping electrode of the present invention forms a large-area electrical contact with the upper and lower surface edges of the metal strip, rather than a linear contact with the side of the metal strip, thereby solving the problems of poor contact and easy sparking caused by wear of the electrode sheet and the side of the metal strip during the long-term continuous running of the metal strip, and the problem that metal strips of different widths, thicknesses, and bending strengths are easily deformed or twisted due to the side pressure. The present invention can be used for coating metal strips of different widths, thicknesses, and bending strengths. During the continuous running process, the Joule heat generated by the stable current provided by the self-heating device of the metal strip is used to quickly reach the required temperature for coating, thereby realizing rapid temperature rise and fall, high energy efficiency, and realizing continuous and stable preparation of thin films on moving or fixed metal strips.

[0040] The double CVD precursor shower head is set close to the metal strip so that more deposition particles are adsorbed on the upper and lower surfaces of the metal strip without being carried away by the gas phase transmission system. Plasma-assisted deposition helps more precursor particles adsorbed on the heated metal strip to reach the reaction activation energy, increase the number of activated particles, reduce the number of clustered particles, increase the utilization rate of precursor particles on the metal strip surface, improve the film quality and increase the coating rate;

[0041] The above advantages of the present invention are particularly important for the industrial preparation of thin films, and can significantly improve coating efficiency and reduce energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the three-dimensional structure and circuit connection of Example 1 of the present invention;

[0043] Figure 2 This is a schematic diagram of the three-dimensional structure of the positive electrode group of Example 1 of the present invention;

[0044] Figure 3 This is a schematic diagram of the positive electrode group in the front view of Example 1 of the present invention;

[0045] Figure 4 It is a cross-sectional view of the positive electrode group along the second through groove direction of Example 1 of the present invention;

[0046] Figure 5 A cross-sectional view of the clamped electrode sheet at the bottom of Example 1 of the present invention;

[0047] Figure 6 This is a cross-sectional view of the clamping electrode sheet and the metal strip in embodiment 1 of the present invention;

[0048] Figure 7 for Figure 6 The enlarged schematic diagram of part A in the middle;

[0049] Figure 8 This is an equivalent circuit diagram of a current distribution circuit of a powered self-heating device according to Embodiment 1 of the present invention;

[0050] Fig. 9 This is a schematic diagram of the thin film deposition area in the front view direction of Example 1 of the present invention;

[0051] Fig.10 This is a schematic diagram of the roller-type electrode in the front view direction of Example 2 of the present invention;

[0052] Fig.11 This is a schematic diagram of the front view direction of the rolling ball type electrode of Example 3 of the present invention;

[0053] Fig.12 This is a schematic diagram of the three-dimensional structure of a track-type electrode according to Embodiment 4 of the present invention;

[0054] Fig.13 2θ scanning curve of XRD test of YBCO thin film on metal strip in Example 5;

[0055] Fig.14 These are the ω scan and φ scan curves of XRD of the double-sided YBCO film on the metal strip of Example 5. DETAILED DESCRIPTION

[0056] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0057] Example 1

[0058] Figures 1 to 9The first specific embodiment of the metal thin-band double-sided high-efficiency CVD continuous coating system of the present invention is shown. The coating system is installed in a reaction chamber and includes a winding disk 1, a metal thin-band energized self-heating device, a plasma-assisted coating device, a CVD precursor shower head 17, and an anti-deposition protection member 18, wherein:

[0059] The specific structure of the metal strip energized self-heating device is as follows:

[0060] A positive electrode group 2 and a negative electrode group 3 are arranged between the two winding disks 1, and a thin film deposition area 5 is formed between the positive electrode group 2 and the negative electrode group 3; a metal thin strip 12 wound on one side of the winding disk 1 passes through the positive electrode group 2, and after passing through the thin film deposition area 5, is pulled to the negative electrode group 3 by the winding disk 1 on the other side; the movement path of the metal thin strip 12 between the winding disks 1 forms a substrate channel;

[0061] The positive electrode group 2 includes a power interface, a current distribution circuit and 8 pairs of clamping electrodes 10. The upper and lower clamping electrodes 10 of each pair of clamping electrodes 10 are distributed above and below the substrate channel and form electrical contact with the upper and lower surface edges of the metal strip 12; the two pairs of clamping electrodes 10 are electrically connected to each other and are electrically connected to the power interface through the current distribution circuit;

[0062] The specific structure of the positive electrode group 2 is as follows: a first through groove is opened in the middle of a placement plate 11 made of an insulating material along the direction of the substrate channel, and at least two pairs of second through grooves are opened on both sides of the placement plate 11 at the first through groove, and the second through grooves are perpendicular to the first through grooves. An upper and a lower clamping electrode 10 are arranged in each pair of second through grooves, and the clamping electrode 10 is an electrode sheet with a groove 10a in the middle, wherein the groove 10a of the upper electrode sheet is opened downward and placed, and the groove 10a of the lower electrode sheet is opened upward, and the upper and lower electrodes are placed in the middle of the electrode sheet. The grooves 10a of the electrode sheets 10 are aligned; the grooves 10a are located in the first through grooves and their direction is consistent with the first through grooves, and the two sides of the grooves 10a are at a set distance from the two sides of the first through grooves; the metal strip 12 passes through the gap between the upper and lower electrode sheets 10 and is confined in the first through groove of the placement plate 11, the central part of the metal strip 12 is located within the range of the grooves 10a, and the upper and lower surface edges of the metal strip 12 are respectively in electrical contact with the surfaces of the upper and lower electrode sheets 10 located on both sides of the grooves 10a;

[0063] The rods of 16 bolts 13 distributed on both sides of the substrate channel respectively pass through the mounting holes on both sides of the placement plate 11, the lower electrode sheet, and the upper electrode sheet from bottom to top. One bolt 13 is arranged on both sides of each pair of electrode sheets. A nut 7 is installed at the rod of the bolt 13 located above the upper electrode sheet. A spring 8 sleeved on the rod of the bolt 13 is installed between the nut 7 and the upper electrode sheet.

[0064] Each pair of electrode sheets also has a positioning through hole on both sides, and the positioning rod 9 on the placement plate 11 passes through the positioning through hole;

[0065] The current distribution circuit is a series of shunt resistors 6, each of which is sequentially installed and connected between adjacent bolts 13. In this embodiment, the specific connection point is located at the top of the rod of the bolt 13, and each pair of clamping electrodes 10 is electrically connected to the connection point of the adjacent shunt resistor 6 and the two ends of the resistor string through the bolt 13; the head of the outermost bolt 13 located below the placement plate 11 serves as the power interface of the positive electrode group 2;

[0066] The structure of the negative electrode group 3 is the same as that of the positive electrode group 2;

[0067] The positive electrode group 2 and the negative electrode group 3 are connected to the direct current source 4 through their respective power supply interfaces to form a complete circuit;

[0068] The plasma assisted coating device is arranged in the thin film deposition area 5, and its specific structure is as follows:

[0069] The RF current source 14 is connected to at least one pair of first RF electrodes 15 and second RF electrodes 16 disposed on both sides of the substrate channel in the thin film deposition area through a RF circuit, and a plasma excitation area is formed between the first RF electrodes 15 and the second RF electrodes 16;

[0070] There are two CVD precursor shower heads 17, which are respectively arranged above and below the substrate channel of the thin film deposition area 5. The spray outlet of the CVD precursor shower head 17 is located in the plasma excitation area, and the distance between the spray outlet and the surface of the metal strip 12 is 0.5 to 1 cm.

[0071] There are two anti-deposition protection members 18, which are respectively arranged on both sides of the substrate channel between the positive electrode group 2 and the negative electrode group 3 and between the first RF electrode 15 and the second RF electrode 16. The anti-deposition protection member 18 is a horizontally arranged long strip, and its length is greater than the length of the thin film deposition area 5. A protection groove 18a for protecting the edge of the metal strip 12 is provided on the inner side of the anti-deposition protection member 18. The width of the protection groove 18a is not less than the clamping width between the clamping electrode 10 and the edge of the metal strip 12, and the height of the protection groove 18a is greater than the thickness of the metal strip 12. The anti-deposition protection member 18 is made of a quartz plate.

[0072] In this embodiment, the material of the electrode sheet is Ag-W alloy, the material of the mounting plate 11 is zirconia ceramic, the material of the bolt 13, nut 7, spring 8, and positioning rod 9 is high-temperature nickel-based alloy, and the shunt resistor 6 is a wire-wound resistor.

[0073] Example 2

[0074] The second specific embodiment of the metal thin-band double-sided high-efficiency CVD continuous coating system of the present invention is installed in a reaction chamber, and includes a winding disk 1, a metal thin-band energized self-heating device, a plasma-assisted coating device, a CVD precursor shower head 17, and an anti-deposition protection member 18, wherein:

[0075] The specific structure of the metal strip energized self-heating device is as follows:

[0076] A positive electrode group 2 and a negative electrode group 3 are arranged between the two winding disks 1, and a thin film deposition area 5 is formed between the positive electrode group 2 and the negative electrode group 3; a metal thin strip 12 wound on one side of the winding disk 1 passes through the positive electrode group 2, and after passing through the thin film deposition area 5, is pulled to the negative electrode group 3 by the winding disk 1 on the other side; the movement path of the metal thin strip 12 between the winding disks 1 forms a substrate channel;

[0077] The positive electrode group 2 includes a power interface, a current distribution circuit and at least two pairs of clamping electrodes 10. The upper and lower clamping electrodes 10 of each pair of clamping electrodes 10 are distributed above and below the substrate channel and are in electrical contact with the upper and lower surface edges of the metal strip 12. The two pairs of clamping electrodes 10 are electrically connected to each other and are electrically connected to the power interface through the current distribution circuit. The current distribution circuit is a series shunt resistor 6, which is a wire-wound resistor.

[0078] like Fig.10 As shown, in this embodiment, the clamping electrode 10 is a roller electrode, that is, the electrode is made into a roller shape and can rotate around the wheel shaft; the roller electrode 10 is installed in the reaction chamber through the wheel shaft and is distributed at the two edges of the upper and lower surfaces of the metal strip 12; the material of the roller electrode is Ag-W alloy;

[0079] The structure of the negative electrode group 3 is the same as that of the positive electrode group 2;

[0080] The positive electrode group 2 and the negative electrode group 3 are connected to the direct current source 4 through their respective power supply interfaces to form a complete circuit;

[0081] The plasma assisted coating device is arranged in the thin film deposition area 5, and its specific structure is as follows:

[0082] The RF current source 14 is connected to at least one pair of first RF electrodes 15 and second RF electrodes 16 disposed oppositely on both sides of the substrate channel through a RF circuit, and a plasma excitation region is formed between the first RF electrodes 15 and the second RF electrodes 16;

[0083] There are two CVD precursor shower heads 17, which are respectively arranged above and below the substrate channel of the thin film deposition area 5. The spray outlet of the CVD precursor shower head 17 is located in the plasma excitation area, and the distance between the spray outlet and the surface of the metal strip 12 is 0.5 to 1 cm.

[0084] There are two anti-deposition protection members 18, which are respectively arranged on both sides of the substrate channel between the positive electrode group 2 and the negative electrode group 3 and between the first RF electrode 15 and the second RF electrode 16. The anti-deposition protection member 18 is a horizontally arranged long strip, and its length is greater than the length of the thin film deposition area 5. A protection groove 18a for protecting the edge of the metal strip 12 is provided on the inner side of the anti-deposition protection member 18. The width of the protection groove 18a is not less than the clamping width between the clamping electrode 10 and the edge of the metal strip 12, and the height of the protection groove 18a is greater than the thickness of the metal strip 12. The anti-deposition protection member 18 is made of a quartz plate.

[0085] The structure of this embodiment is mostly the same as that of the first embodiment, except that the clamping electrode 10 is a roller electrode.

[0086] Example 3

[0087] The third specific implementation of the metal thin-band double-sided high-efficiency CVD continuous coating system of the present invention is basically the same as the structure of Example 2, the only difference being that the clamping electrode 10 is a rolling ball electrode, such as Fig.11 As shown, the electrode is made into a spherical shape and can rotate around the center of the sphere; the rolling ball electrode 10 is installed in the reaction chamber through the axle and is distributed at the two edges of the upper and lower surfaces of the metal strip 12; the material of the rolling ball electrode is Ag-W alloy.

[0088] Example 4

[0089] The fourth specific embodiment of the metal thin-band double-sided high-efficiency CVD continuous coating system of the present invention is basically the same as the structure of Example 2, the only difference being that the clamping electrode 10 is a track-type electrode, including a track 101 and a roller 102 in the track, such as Fig.12 As shown, the track electrode 10 is installed in the reaction chamber through the axle and distributed at the two edges of the upper and lower surfaces of the metal strip 12, and its track 101 is in electrical contact with the upper and lower surface edges of the metal strip 12; the material of the track electrode is Ag-W alloy.

[0090] Example 5

[0091] A specific implementation of the metal thin-band double-sided high-efficiency CVD continuous coating method of the present invention uses the coating system shown in Example 1 and is applied to YBa 2 Cu 3 O 7-x (YBCO) superconducting film preparation, comprising the following steps:

[0092] Before coating, please do the following preparations:

[0093] On the Hastelloy metal strip 12 with a buffer layer prepared, the buffer layer is removed from the upper and lower edges of the metal strip 12 through an independently developed process to achieve good electrical contact; the metal strip 12 is 30 mm wide; the buffer layer is LaMnO 3 / homo-epi MgO / IBAD-MgO / SDP-Y 2 O 3 / Hastelloy;

[0094] Specific steps of coating:

[0095] S1. Pass the metal strip 12 between the upper and lower clamping electrode sheets 10 of the positive electrode group 2, and then pull the metal strip 12 to the negative electrode group 3 after passing through the thin film deposition area 5, and then pass through the upper and lower clamping electrode sheets 10 of the negative electrode group 3. Specifically, the metal strip 12 passes through the gap between the upper and lower electrode sheets 10 and is confined in the first through groove of the placement plate 11; the central part of the metal strip 12 is located within the range of the groove 10a of the electrode sheet 10, and the surfaces of the upper and lower electrode sheets 10 located on both sides of the groove 10a form electrical contact with the upper and lower surface edges of the metal strip 12 respectively; adjust the nut 7 to squeeze the spring 8, and then apply pressure to the electrode sheet 10 to ensure that the electrode sheet 10 clamps the upper and lower surface edges of the metal strip 12 and has good mutual pressure, so that the metal strip 12 has good electrical contact with the electrode sheet 10 and can slide smoothly;

[0096] S2, the heating current provided by the DC current source 4 is shunted through the current distribution circuit of the positive electrode group 2, that is, the series shunt resistor 6, and gradually introduced into the metal strip 12 from the upper and lower surface edges of the metal strip 12, and the current is gradually led out and merged through the current distribution circuit of the negative electrode group 3 to form a complete loop, relying on the Joule heat generated by the resistance of the metal strip 12 itself to reach the temperature required for film growth; the shunt resistor 6 ensures that the current is gradually input, and the shunt resistor diagram of the positive electrode group 2 and the negative electrode group 3 is as shown in Figure 8 As shown in the figure, in this embodiment, 8 pairs of Ag-W alloy clamping electrode sheets are used. Assuming that the resistance of the Ag-W alloy clamping electrode sheets is negligible, in order to make the current on each Ag-W alloy clamping electrode sheet equal, assuming that the current is I, the total current required for heating is 8I. According to Kirchhoff's law, the shunt resistance R n =R*n / (8-n), the shunt resistance value in this embodiment is calculated and set according to the above formula.

[0097] S3. Then, weigh a certain proportion Y (DPM) 3 、Ba(DPM) 2 and Cu(DPM) 2, and fully dissolved in tetrahydrofuran solvent by a magnetic stirrer to form a uniform and clear metal organic source precursor; the reaction chamber was evacuated to below 10Pa, and a certain proportion of Ar gas, O 2 and N 2 O, adjust the current source indication, and pass a 25A heating current to the metal strip 12; turn on the RF current source 14 and stabilize it for five minutes. The frequency of the RF current source 14 is 13.56MHZ, and the transmission power is 0-1000W. The metal organic source precursor is pumped into the 300°C evaporation chamber by a peristaltic pump to flash into a metal organic source vapor, and then driven by Ar gas through a 320°C gas pipeline and sprayed by a CVD precursor shower head 17 to the middle area of ​​the upper and lower surfaces of the metal strip 12. At the same time, the upper and lower surface edges of the metal strip are shielded by an anti-deposition protective member. Plasma is formed between the first RF electrode 15 and the second RF electrode 16 of the plasma-assisted coating device, and finally a YBCO film is generated by reaction in the middle area of ​​the upper and lower surfaces of the metal strip 12 that is powered and heated.

[0098] After taking out the metal strip on which the YBCO thin film has been continuously prepared for a long time, place it in a 2 The film was annealed at 500 °C for 30 min in a tube furnace to characterize its structure.

[0099] Fig.13 It is a double-sided YBa prepared on a metal strip 2 Cu 3 O 7-x 2θ scanning curve of XRD test of (YBCO) film. As can be seen from the figure, the diffraction peak intensity of the (00l) surface of the film is strong and sharp without impurity peaks, indicating that YBCO grows along the c-axis direction and has good crystal quality.

[0100] Fig.14 The XRD ω scan and φ scan curves of the YBCO film on the metal strip are measured. From the curve fitting in the figure, it can be seen that the out-of-plane half-width values ​​of the double-sided are 2.2° and 2.5°, and the in-plane half-width values ​​of the double-sided are 4.1° and 5.2°, indicating that the film has good out-of-plane and in-plane textures.

[0101] It can be seen that the YBCO film prepared by the present invention has a good texture.

[0102] In summary, the metal thin-band wide-band double-sided high-efficiency CVD continuous coating system and method of the present invention can prepare high-quality films, improve film quality and increase film deposition rate, and ensure film quality and uniformity during the continuous coating process.

[0103] The above embodiments of the present invention are merely examples for illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes and modifications can be made based on the above description. It is impossible to list all the embodiments here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A metal thin broadband double-sided high-efficiency CVD continuous coating system, characterized in that: It comprises a winding disk (1), a metal strip energized self-heating device, a plasma-assisted film coating device, a CVD precursor shower head (17), and an anti-deposition protection element (18), wherein: The specific structure of the metal strip energized self-heating device is as follows: A positive electrode group (2) and a negative electrode group (3) are arranged between the two winding disks (1), and a thin film deposition area (5) is provided between the positive electrode group (2) and the negative electrode group (3); a metal thin strip (12) wound on the winding disk (1) on one side passes through the positive electrode group (2), passes through the thin film deposition area (5), and is pulled to the negative electrode group (3) by the winding disk (1) on the other side; the movement path of the metal thin strip (12) between the winding disks (1) forms a substrate channel; The positive electrode group (2) comprises a power interface, a current distribution circuit and at least two pairs of clamping electrodes (10); the upper and lower clamping electrodes (10) of each pair of clamping electrodes (10) are distributed above and below the substrate channel and are in electrical contact with the upper and lower surface edges of the metal thin strip (12); the two clamping electrodes (10) in a pair are electrically connected to each other and are electrically connected to the power interface through the current distribution circuit; The structure of the negative electrode group (3) is the same as that of the positive electrode group (2); The positive electrode group (2) and the negative electrode group (3) are connected to an external direct current source (4) through their respective power supply interfaces to form a complete circuit; The plasma-assisted coating device is arranged in the thin film deposition area (5), and its specific structure is as follows: A radio frequency current source (14) is connected to at least one pair of a first radio frequency electrode (15) and a second radio frequency electrode (16) arranged oppositely on both sides of the substrate channel through a radio frequency circuit, and a plasma excitation region is formed between the first radio frequency electrode (15) and the second radio frequency electrode (16); There are two CVD precursor shower heads (17), which are respectively arranged above and below the substrate channel of the thin film deposition area (5); the shower outlet of the CVD precursor shower head (17) is located in the plasma excitation area; The number of the anti-deposition protection members (18) is two, which are respectively arranged on both sides of the substrate channel between the positive electrode group (2) and the negative electrode group (3) and located between the first radio frequency electrode (15) and the second radio frequency electrode (16); the anti-deposition protection member (18) is in the shape of a horizontally arranged long strip, the length of which is greater than the length of the thin film deposition area (5); a protection groove (18a) for protecting the edge of the metal strip (12) is provided on the inner side of the anti-deposition protection member (18); the width of the protection groove (18a) is not less than the clamping width between the clamping electrode (10) and the edge of the metal strip (12); and the height of the protection groove (18a) is greater than the thickness of the metal strip (12).

2. A metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 1, characterized in that: The current distribution circuit is a series of shunt resistors (6), and each pair of clamping electrodes (10) is respectively connected to the connection point of adjacent shunt resistors (6) and the two ends of the resistor string.

3. A metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 2, characterized in that: The shunt resistor (6) is one of a wire-wound resistor, a carbon film resistor, and a metal film resistor.

4. The metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 1, characterized in that: The specific structure of the positive electrode group (2) is: A first through slot along the direction of the substrate channel is provided in the middle of a placement plate (11) made of insulating material, and at least two pairs of second through slots are provided on both sides of the first through slot, wherein the second through slots are perpendicular to the first through slot, and an upper and a lower clamping electrode (10) are provided in each pair of second through slots, wherein the clamping electrode (10) is an electrode sheet with a groove (10a) in the middle, wherein the groove (10a) of the upper electrode sheet is opened downward and placed, and the groove (10a) of the lower electrode sheet is opened upward and placed, and the grooves (10a) of the upper and lower electrode sheets are aligned; the groove (10a) is located in the first through slot and its direction is consistent with that of the first through slot, and the two side edges of the groove (10a) are at a set distance from the two side edges of the first through slot; The rod of the bolt (13) passes through the mounting holes on both sides of the placement plate (11), the lower electrode sheet, and the upper electrode sheet in sequence from bottom to top; a nut (7) is installed on the rod of the bolt (13) above the upper electrode sheet; and a spring (8) sleeved on the rod of the bolt (13) is installed between the nut (7) and the upper electrode sheet; Both sides of the upper and lower electrode sheets are also provided with positioning through holes, and the positioning rods (9) on the placement plate (11) pass through the positioning through holes; The structure of the negative electrode group (3) is the same as that of the positive electrode group (2).

5. A metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 4, characterized in that: The material of the electrode sheet is one of Ag-W alloy, Ag-WC alloy and Ag-Cu alloy.

6. The metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 1, characterized in that: The distance between the spray outlet of the CVD precursor spray head (17) and the surface of the metal thin strip (12) is 0.5 to 1 cm.

7. The metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 1, characterized in that: The material of the placement plate (11) is one of zirconium oxide ceramics, silicon oxide ceramics, boron nitride ceramics, and polytetrafluoroethylene insulation materials, and the anti-deposition protection member (18) is made of a quartz plate.

8. The metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 1, characterized in that: The clamping electrode (10) is a roller electrode or a rolling ball electrode.

9. The metal thin-film wide-band double-sided high-efficiency CVD continuous coating system according to claim 1, characterized in that: The clamping electrode (10) is a track-type electrode.

10. A method for coating using the metal thin-band double-sided high-efficiency CVD continuous coating system as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1, passing the metal strip between the upper and lower clamping electrodes of the positive electrode group, pulling it to the negative electrode group after passing through the film deposition area, and then passing it out from between the upper and lower clamping electrodes of the negative electrode group; The upper and lower clamping electrodes are in good electrical contact with the upper and lower surface edges of the metal strip; S2. The heating current provided by the DC current source is divided through the current distribution circuit of the positive electrode group and gradually introduced into the metal strip from the upper and lower surface edges of the metal strip. The current is then gradually led out and merged through the current distribution circuit of the negative electrode group to form a complete loop. The Joule heat generated by the resistance of the metal strip itself is used to reach the temperature required for film growth. S3. Precursor particles are sprayed by a CVD precursor double spray head onto the middle area of ​​the upper and lower surfaces of the substrate channel in the thin film deposition area. At the same time, the upper and lower surface edges of the metal strip are shielded by anti-deposition protection. Plasma energy is introduced into the precursor particles between the first RF electrode and the second RF electrode of the plasma-assisted coating device. The precursor particles react in the middle area of ​​the upper and lower surfaces of the metal strip that is electrically heated to form a thin film.

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