Automatic feeding method and device for vacuum coating

Abstract

The invention discloses a vacuum coating automatic feeding method and device.The device comprises a feeding mechanism, a storage tank, a transmission mechanism, a closed-loop controller, a crystal vibration film thickness detector, a heating mechanism, a vacuum pumping system, an electronic gun and a crucible. The process comprises the following steps that S1, stored material heating is conducted, specifically, a coating material is put into the storage tank, the vacuum pumping system is started, and the coating material is heated; the heating function of the storage tank is started in the rough pumping process, the plating material is fully degassed, and the vacuum degree reduction caused by feeding is avoided; the mechanism is simple, convenient to install, capable of meeting the crucible feeding requirements of various vacuum coating machines, easy to control and capable of conducting closed-loop control over a feeding-evaporation system with a film thickness gauge crystal oscillation system, it is guaranteed that the evaporation state in the whole coating process is consistent, the storage tank conducts baking and degassing, and the coating quality is improved. The length of the screw rod can be adjusted, feeding at different positions can be carried out according to different materials, and the stability of evaporation of a molten pool is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum coating and vacuum coating equipment, and in particular to a method and device for automatic feeding of vacuum coating. Background Art

[0002] Vacuum evaporation coating equipment, also known as vacuum evaporation coating machine. There are many types and different models. If classified according to their operation mode, there are three types: intermittent (periodic), semi-continuous or continuous. Vacuum evaporation winding coating machine is a technology that uses evaporation method under vacuum to achieve continuous coating on flexible substrates.

[0003] In general vacuum winding thermal evaporation aluminum coating machines, the coating material is aluminum wire, and a feeding mechanism plus a stepper motor are used to transport the coating material to ensure continuous production of the product. When using evaporation source types such as electron beam and induction heating, crucibles are usually used for heating. The coating material is generally granular, and there is no automatic feeding device. A large amount of coating material needs to be placed in the crucible before each work. This situation will cause the following problems: 1. As the coating material is consumed, the distance from the evaporation source to the substrate will become farther and farther, which will lead to an increase in the evaporation distance, resulting in uneven products; 2. Limited production capacity and low efficiency.

[0004] Jiangsu Feiwotai Nanotechnology Co., Ltd.'s CN118086870A vacuum coating automatic feeding device is used for CVD tube furnaces, not for feeding in crucibles for evaporation. Guangdong Leibao Optoelectronics Technology Co., Ltd.'s CN216237267U is a traditional wire feeding aluminum plating machine. Fujian Jinshi Energy Co., Ltd.'s CN 220116646U is a continuous feeding vacuum evaporation coating source system that does not consider the feeding of granular coating materials. Wuxi Jidian Photonics Technology Co., Ltd.'s CN219218130U is not suitable for winding coating equipment.

[0005] When the applicant implemented the method as planned, he found three major technical difficulties: first, the traditional funnel-type feeding cannot be controlled to be opened and closed, resulting in powder material entering the crucible during vacuum pumping, which will cause the surface of the plating material to be uneven, seriously affecting the coating process; second, the vibrating feeding mechanism can easily cause resonance on the surface of the crucible, which has a serious impact on the process; third, the feeding mechanism of rod-shaped film materials is simple, but for many plating materials, granular materials are simple and cheap to source, and the density will decrease after sintering and pressing into rods. The amount of gas released during evaporation will increase, resulting in a decrease in the purity of the film material deposited on the surface of the substrate.

[0006] In summary, how to add an automatic feeding device without affecting the normal evaporation process and control the feeding quantity to be equal to the evaporation rate and ensure that the evaporation parameters remain unchanged during long-term operation has always been a technical challenge facing researchers of vacuum winding crucible coating equipment materials. Summary of the invention

[0007] The object of the present invention is to provide a method and device for automatic feeding of vacuum coating to solve the related problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a method for automatic feeding of vacuum coating, comprising a feeding mechanism, a storage tank, a transmission mechanism, a closed-loop control, a crystal oscillator film thickness detector, a heating mechanism, a vacuum exhaust system, an electron gun and a crucible, wherein the process steps are as follows:

[0009] S1. Material storage heating: put the plating material into the material storage tank and turn on the vacuum pumping system. During the rough pumping process, turn on the heating function of the material storage tank to fully degas the plating material to avoid a decrease in vacuum due to material addition;

[0010] S2, vacuum coating: When the vacuum degree of the electron gun is reached, the electron gun is turned on to preheat the plating material in the crucible at a low power, the beam current is turned on to 100mA, the crucible is turned on to rotate and the baffle is closed to prevent damage to the substrate, and when the specified vacuum degree is reached, the beam current is increased and the baffle is opened for coating;

[0011] S3, feeding detection: the evaporation amount is measured by a crystal oscillator film thickness detector, and PID feeding adjustment is performed. The evaporation amount is calculated by inputting the material density, and the servo motor is fed back to adjust the feeding speed for feeding;

[0012] S4, automatic material replenishment: the plating material stored in the storage tank is pushed into the crucible through the screw to achieve automatic material replenishment.

[0013] Preferably, the heating mechanism is a hot and cold exchanger for heating, and the maximum temperature of the hot and cold exchanger reaches above 100°C.

[0014] The present invention also includes a feeding device used in the method for automatic feeding of vacuum coating, including an electron gun, a crucible rotating mechanism, a storage tank, a servo motor, a screw mechanism and a crystal oscillator film thickness meter. The top of the crucible rotating mechanism is provided with a rotatably adjustable crucible, the top of the servo motor is linked to a transmission mechanism, a transmission meshing bevel gear is provided between the transmission mechanism and the screw mechanism, and the storage tank respectively includes a feed port and hot water.

[0015] Preferably, the servo motor and the transmission mechanism are interconnected for transmission, two bevel gears are connected to the top of the transmission shaft of the transmission mechanism, and one set of the bevel gears is interconnected with the screw mechanism.

[0016] Preferably, the storage tank is made of 304 non-magnetic stainless steel after polishing and has a double-layer structure, and the middle flow channel is equipped with medium heating.

[0017] Preferably, the transmission mechanism and the servo motor are dynamically sealed using magnetic fluid, wherein the servo motor is arranged outside the vacuum chamber.

[0018] Preferably, a telescopic section is provided on the inner side of the screw mechanism, and the outer side of the screw mechanism is made of polished 304 non-magnetic stainless steel.

[0019] Preferably, the bottom of the material storage tank is a hollow shaft, and the hollow shaft is fixed to the vacuum cavity of the material storage tank through a vacuum flange, and the screw mechanism is arranged at the connection between the hollow shaft and the material storage tank.

[0020] Compared with the prior art, the present invention provides a method for automatic feeding of vacuum coating, which has the following beneficial effects:

[0021] 1. The mechanism designed by the present invention is relatively simple and easy to install, and can meet the crucible feeding requirements of various vacuum coating machines.

[0022] 2. The present invention is easy to control and can be used with the crystal oscillator system of the film thickness meter to perform closed-loop control of the feeding-evaporation system to ensure that the evaporation state is consistent throughout the entire coating process.

[0023] 3. The material storage tank of the present invention is baked and degassed without causing any burden to the vacuum exhaust system.

[0024] 4. The screw of the present invention can be adjusted in length, and can be fed to different positions for different materials, thereby ensuring stable evaporation of the molten pool. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 It is a cross-sectional view of a storage tank of the present invention.

[0027] In the figure: 1. electron gun; 2. crucible; 3. crucible rotating mechanism; 4. storage tank; 5. servo motor; 6. transmission mechanism; 7. bevel gear; 8. screw mechanism; 9. crystal oscillator film thickness meter; 10. feed inlet; 11. hot water. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] See also Figure 1-2The present invention provides a technical solution: including a feeding mechanism, a storage tank, a transmission mechanism, a closed-loop control, a crystal oscillator film thickness detector, a heating mechanism, a vacuum exhaust system, an electron gun and a crucible, and the process steps are as follows:

[0030] S1. Material storage heating: Place the plating material in the material storage tank and start the vacuum pumping system. During the rough pumping process, turn on the heating function of the material storage tank to fully degas the plating material to avoid a decrease in vacuum due to adding materials. The heating mechanism is a hot and cold exchanger for heating, and the maximum temperature of the hot and cold exchanger reaches above 100°C.

[0031] S2, vacuum coating: When the vacuum degree of the electron gun is reached, the electron gun is turned on to preheat the plating material in the crucible at a low power, the beam current is turned on to 100mA, the crucible is turned on to rotate and the baffle is closed to prevent damage to the substrate, and when the specified vacuum degree is reached, the beam current is increased and the baffle is opened for coating;

[0032] S3, feeding detection: the evaporation amount is measured by a crystal oscillator film thickness detector, and PID feeding adjustment is performed. The evaporation amount is calculated by inputting the material density, and the servo motor is fed back to adjust the feeding speed for feeding;

[0033] S4, automatic material replenishment: the plating material stored in the storage tank is pushed into the crucible through the screw to achieve automatic material replenishment.

[0034] A feeding device used in a method for automatic feeding of vacuum coating comprises an electron gun 1, a crucible rotating mechanism 3, a storage tank 4, a servo motor 5, a screw mechanism 8 and a crystal oscillator film thickness meter 9. A crucible 2 for rotation adjustment is provided on the top of the crucible rotating mechanism 3. A transmission mechanism 6 is linked to the top of the servo motor 5. A bevel gear 7 for transmission engagement is provided between the transmission mechanism 6 and the screw mechanism 8. The storage tank 4 comprises a feed port 10 and hot water 11.

[0035] As a preferred solution of this embodiment: the servo motor 5 and the transmission mechanism 6 are interconnected for transmission, the top of the transmission shaft of the transmission mechanism 6 is connected to two bevel gears, and one set of the bevel gears is interconnected with the screw mechanism 8.

[0036] As a preferred solution of this embodiment: the storage tank 4 is made of 304 non-magnetic stainless steel after polishing and has a double-layer structure, and the middle flow channel is equipped with medium heating.

[0037] As a preferred solution of this embodiment: the transmission mechanism 6 and the servo motor 5 are dynamically sealed using magnetic fluid, wherein the servo motor 5 is arranged outside the vacuum chamber, so that more models of servo motors can be selected.

[0038] As a preferred solution of this embodiment: a telescopic section is provided on the inner side of the screw mechanism 8, and the outer side of the screw mechanism 8 is made of polished 304 non-magnetic stainless steel, and feeding of different materials can be achieved by adjusting the feeding position.

[0039] As a preferred solution of this embodiment: the bottom of the storage tank 4 is a hollow shaft, and the hollow shaft is fixed to the vacuum cavity of the storage tank 4 through a vacuum flange, and the screw mechanism 8 is arranged at the connection between the hollow shaft and the storage tank 4.

[0040] Embodiment 1: The storage tank 4 is made of 304 non-magnetic stainless steel with a double-layer structure. The middle flow channel is equipped with medium heating, which can be heated by a hot and cold exchanger. The maximum temperature can reach above 100°C. In this embodiment, SiO granular plating material is used with a particle size of 1-3mm. After the plating material is placed in the storage tank 4, the vacuum exhaust system is turned on. During the rough extraction process, the heating function of the storage tank 4 is turned on to fully degas the plating material to avoid the vacuum degree from decreasing due to the addition of materials. When the vacuum degree of the electron gun 1 is turned on, 6×10 -2 Pa, turn on the electron gun 1 to preheat the plating material in the crucible 2 at a low power, turn on the beam to 100 mA, turn on the crucible 2 to rotate and close the baffle to prevent damage to the substrate, and reach 8.0×10 -3 When the vacuum degree is Pa, the beam current is increased and the baffle is opened for coating. The material is fed according to the film thickness-evaporation feeding program of the automatic control program. Since the phase change during SiO2 evaporation is sublimation, automatic feeding is achieved by feeding the material one by one through the feeding mechanism. The power of the screw feeder 8 comes from the servo motor 5, the transmission shaft 6, and the bevel gear 7. The storage tank 4 has a hollow shaft below, which is fixed on the vacuum chamber through a vacuum flange. The connection between the hollow shaft and the storage tank 4 is equipped with a screw feeding mechanism 8, and the material is fed by the screw feeding mechanism 8.

[0041] Embodiment 2: The storage tank 4 is made of 304 non-magnetic stainless steel with a double-layer structure. The middle flow channel is equipped with medium heating, which can be heated by a hot and cold exchanger. The maximum temperature can reach above 100°C. In this embodiment, Al2O3 granular plating material is used with a particle size of 1-3mm. After the plating material is placed in the storage tank 4, the vacuum exhaust system is turned on. During the rough extraction process, the heating function of the storage tank 4 is turned on to fully degas the plating material to avoid the vacuum degree from decreasing due to the addition of materials. The vacuum degree of the electron gun is turned on to reach 6×10 -2 Pa, turn on the electron gun 1 to preheat the plating material in the crucible 2 at a low power, turn on the beam to 100 mA, turn on the crucible 2 to rotate and close the baffle to prevent damage to the substrate, and reach 8.0×10 -3When the vacuum degree is Pa, the beam current is increased and the baffle is opened for coating, and the material is fed according to the film thickness-evaporation feeding program of the automatic control program, wherein the power of the screw feeding mechanism comes from the servo motor 5, the transmission shaft 6, and the bevel gear 7. There is a hollow shaft under the storage tank 4, which is fixed to the vacuum chamber through a vacuum flange. A screw feeding mechanism 8 is installed at the connection between the hollow shaft and the storage tank 4, and the screw feeding mechanism 8 is used to feed the material.

[0042] The difference from Example 1 is that the phase change of Al2O3 during the evaporation process is solid-liquid-gas. In order to avoid adding the particles directly into the molten pool, the screw is moved forward by 2 cm, that is, before the molten pool, in the heat affected zone.

[0043] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for automatic feeding of vacuum coating, comprising a feeding mechanism, a storage tank, a transmission mechanism, a closed-loop control, a crystal oscillator film thickness detector, a heating mechanism, a vacuum exhaust system, an electron gun and a crucible, wherein the process steps are as follows: S1. Material storage heating: put the plating material into the material storage tank and turn on the vacuum pumping system. During the rough pumping process, turn on the heating function of the material storage tank to fully degas the plating material to avoid a decrease in vacuum due to material addition; S2, vacuum coating: When the vacuum degree of the electron gun is reached, the electron gun is turned on to preheat the plating material in the crucible at a low power, the beam current is turned on to 100mA, the crucible is turned on to rotate and the baffle is closed to prevent damage to the substrate, and when the specified vacuum degree is reached, the beam current is increased and the baffle is opened for coating; S3, feeding detection: the evaporation amount is measured by a crystal oscillator film thickness detector, and PID feeding adjustment is performed. The evaporation amount is calculated by inputting the material density, and the servo motor is fed back to adjust the feeding speed for feeding; S4, automatic material replenishment: the plating material stored in the storage tank is pushed into the crucible through the screw to achieve automatic material replenishment.

2. The method for automatic feeding of vacuum coating according to claim 1, characterized in that: The heating mechanism heats the hot and cold exchanger, and the maximum temperature of the hot and cold exchanger reaches above 100°C.

3. A feeding device for the automatic feeding method for vacuum coating according to claim 1, characterized in that: The invention comprises an electron gun (1), a crucible rotating mechanism (3), a material storage tank (4), a servo motor (5), a screw mechanism (8) and a crystal oscillator film thickness meter (9); a rotatably adjustable crucible (2) is arranged on the top of the crucible rotating mechanism (3); a transmission mechanism (6) is linked to the top of the servo motor (5); a bevel gear (7) for transmission engagement is arranged between the transmission mechanism (6) and the screw mechanism (8); and the material storage tank (4) comprises a feed port (10) and hot water (11).

4. The automatic feeding device for vacuum coating according to claim 1, characterized in that: The servo motor (5) and the transmission mechanism (6) are connected to each other for transmission, the top of the transmission shaft of the transmission mechanism (6) is connected to two bevel gears, and one set of the bevel gears is connected to the screw mechanism (8).

5. The automatic feeding device for vacuum coating according to claim 1, characterized in that: The storage tank (4) is made of 304 non-magnetic stainless steel after polishing and has a double-layer structure. The middle flow channel is equipped with medium heating.

6. The automatic feeding device for vacuum coating according to claim 1, characterized in that: The transmission mechanism (6) and the servo motor (5) are dynamically sealed using magnetic fluid, wherein the servo motor (5) is arranged outside the vacuum chamber.

7. The automatic feeding device for vacuum coating according to claim 1, characterized in that: A telescopic section is provided on the inner side of the screw mechanism (8), and the outer side of the screw mechanism (8) is made of polished 304 non-magnetic stainless steel.

8. The automatic feeding device for vacuum coating according to claim 1, characterized in that: The bottom of the material storage tank (4) is a hollow shaft, and the hollow shaft is fixed to the vacuum cavity of the material storage tank (4) via a vacuum flange, and the screw mechanism (8) is arranged at the connection between the hollow shaft and the material storage tank (4).

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