Evaporation method and evaporation boat

Abstract

The invention relates to the field of vacuum evaporation coating, and provides an evaporation method and an evaporation boat, the evaporation method comprises the steps that an evaporation container is preheated to a temperature t1, and the temperature t1 is larger than the melting point temperature of an evaporation raw material and smaller than the boiling point temperature of the evaporation raw material; the evaporation raw materials are heated and melted, and the melted evaporation raw materials drop into the evaporation container; and when the molten evaporation raw material is completely paved at the bottom of the whole evaporation container, heating the evaporation raw material at the bottom of the evaporation container so as to evaporate the evaporation raw material. The evaporation raw materials are heated, so that the evaporation raw materials are melted into a liquid state before reaching the bottom of the evaporation container, and the evaporation raw materials are prevented from splashing; and when the liquid evaporation raw material is completely paved on the bottom of the evaporation container, the temperature of the evaporation raw material in the evaporation container is raised, so that the evaporation raw material is evaporated, and the problem of poor coating quality caused by non-uniform distribution of the evaporation raw material and splashing of the evaporation raw material is effectively solved.

Description

Technical Field

[0001] The present application relates to the field of vacuum evaporation coating, and in particular to an evaporation method and an evaporation boat. Background Art

[0002] Vacuum evaporation coating is a coating technology carried out under vacuum conditions. The specific process is to heat the evaporation material (such as aluminum) in a vacuum chamber through an evaporation vessel to sublimate or evaporate it into gaseous particles (atoms, molecules or atomic groups). These gaseous particles are transported to the surface of the substrate in a basically collision-free straight-line flight in a vacuum, and are deposited, condensed, nucleated and grown on the substrate, eventually forming a solid film.

[0003] Wire feeding evaporation coating is a common vacuum evaporation coating method. Wire feeding evaporation coating equipment mainly includes: evaporation boat, electrode, wire feeding mechanism and aluminum wire reel. The wire feeding mechanism transports the aluminum wire on the aluminum wire reel to the evaporation boat; the evaporation boat is connected to the electrode, and by energizing the electrode, the evaporation boat can be heated, thereby melting and evaporating the aluminum wire.

[0004] However, after the aluminum liquid drips into the evaporation boat, it gradually spreads to the surroundings and wets the evaporation boat. Before the aluminum liquid completely wets the bottom of the evaporation boat, the distribution of the aluminum liquid is extremely uneven, which makes the coating formed after the aluminum liquid evaporates likely to have uneven thickness, affecting the coating quality.

[0005] In addition, during the evaporation of aluminum wire, the molten aluminum may splash out. The main reasons for the splashing of aluminum are as follows: 1. Since the aluminum liquid gradually spreads around and wets the evaporation boat, when the aluminum liquid contacts the high-temperature, unwetted part of the boat during the spreading process, it is easy to cause aluminum liquid to splash; 2. The temperature of the evaporation boat's wetted surface is uneven.

[0006] Since the splashed aluminum liquid droplets have higher energy than the energy of a single aluminum liquid atom when it evaporates, the higher temperature aluminum liquid droplets are likely to burn through the substrate when splashing onto the substrate, affecting the coating quality. Summary of the invention

[0007] In order to solve the problem of poor coating quality caused by uneven distribution of evaporation raw materials and splashing of evaporation raw materials, the present application provides an evaporation method and an evaporation boat.

[0008] In a first aspect, the present application provides an evaporation method, comprising the following steps: The evaporation container is preheated to a temperature t1, wherein the temperature t1 is greater than the melting point of the evaporation raw material and less than the boiling point of the evaporation raw material.

[0009] The evaporation raw material is heated to melt, and the melted evaporation raw material is dripped into the evaporation container.

[0010] When the melted evaporation raw material completely covers the entire bottom of the evaporation container, the evaporation raw material at the bottom of the evaporation container is further heated to evaporate the evaporation raw material.

[0011] By adopting the above solution, the evaporation raw material can be melted and spread all over the bottom of the evaporation container before the evaporation process is carried out, thereby avoiding poor coating quality caused by uneven distribution of the evaporation raw material and splashing of the evaporation raw material.

[0012] In a second aspect, the present application also provides an evaporation boat, comprising: The boat body is provided with a molten pool.

[0013] The first heating component is used to heat the boat body.

[0014] The second heating component is arranged above the molten pool and is used to melt and evaporate the raw material.

[0015] By adopting the above scheme, the evaporation boat can be used as an evaporation container, the first heating component can preheat the boat body and heat it during the evaporation process; and the second heating component can melt the evaporation raw material before it enters the molten pool so that the evaporation raw material spreads and wets the bottom of the molten pool.

[0016] Optionally, the boat body is an insulating component.

[0017] By adopting the above scheme, the safety during the heating evaporation process can be improved, and the evaporation raw materials can be prevented from being electrified and boiling and splashing.

[0018] Optionally, the boat body is made of aluminum nitride.

[0019] By adopting the above scheme, when the evaporation raw material is aluminum, it is possible to avoid chemical reaction between the aluminum liquid and the boat body during the evaporation process of the aluminum liquid, thereby preventing the boat body from being corroded and causing aluminum liquid to splash.

[0020] Optionally, the evaporation boat further comprises a mounting seat, a slide groove is provided on the top of the mounting seat, at least one side of the slide groove extends to the edge of the mounting seat, and the boat body is slidably disposed in the slide groove.

[0021] By adopting the above solution, the boat body and the mounting seat can be quickly assembled or separated.

[0022] Optionally, the first heating assembly includes a resistance heating wire and an electrode.

[0023] A placement groove is arranged on the bottom wall of the slide groove, and the resistance heating wire is arranged in the placement groove and abuts against the bottom of the boat body.

[0024] The electrode is connected to the resistance heating wire.

[0025] By adopting the above solution, the resistance heating wire can be hidden by being embedded in the placement groove, and the resistance heating wire can directly transfer heat to the boat body simply by energizing the electrode, with high heat transfer efficiency.

[0026] Optionally, the evaporation boat further comprises a flexible heat-conducting member, and the flexible heat-conducting member is arranged between the resistance heating wire and the boat body.

[0027] By adopting the above solution, the flexible heat-conducting member can fill the gap between the boat body and the resistance heating wire, thereby preventing the boat body from being heated unevenly due to incomplete adhesion between the boat body and the resistance heating wire.

[0028] Optionally, the evaporation boat further comprises a flattening assembly, which comprises a flattening member and a driving assembly connected to each other, wherein the flattening member is at least partially located in the molten pool, and the driving assembly is used to drive the flattening member to move so as to flatten the melted evaporation raw material.

[0029] By adopting the above solution, the flattening component can accelerate the spreading of the liquid evaporation raw material to the bottom of the molten pool, thereby reducing the probability of splashing of the evaporation raw material and improving the efficiency of coating.

[0030] Optionally, the material of the paving piece is the same as that of the evaporation raw material.

[0031] By adopting the above scheme, even if the paving piece melts when paving the evaporation raw material, it will not contaminate the evaporation raw material, and can also replenish the loss of the evaporation raw material.

[0032] Optionally, the second heating assembly comprises an induction coil.

[0033] By adopting the above solution, the second heating component can make the evaporated raw material itself generate heat and melt, thereby preventing the evaporated raw material from contacting other objects and causing contamination or splashing. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of the evaporation method provided in the present application.

[0035] Figure 2 It is a structural schematic diagram of the evaporation boat provided in this application.

[0036] Figure 3 It is a partial schematic diagram of the evaporation boat provided in this application.

[0037] Figure 4 It is a partial exploded view of the evaporation boat provided in this application.

[0038] Description of reference numerals: 1. Mounting seat; 11. Slide groove; 111. Limiting part; 12. Placement groove; 2. boat body; 21. molten pool; 3. First heating component; 31. Resistance heating wire; 32. Electrode; 4. A second heating component; 200. Evaporating raw materials. DETAILED DESCRIPTION

[0039] The following is combined with Figure 1-4 This application is described in further detail.

[0040] like Figure 1 As shown, the embodiment of the present application discloses an evaporation method, comprising the following steps: S100: preheating the evaporation container to a temperature t1, wherein the temperature t1 is greater than the melting point of the evaporation raw material and less than the boiling point of the evaporation raw material; S200: heating and melting the evaporation raw material, so that the melted evaporation raw material drips into the evaporation container; S300: When the melted evaporation raw material completely covers the entire bottom of the evaporation container, the evaporation raw material at the bottom of the evaporation container is further heated to evaporate the evaporation raw material.

[0041] Specifically, before evaporating the evaporation raw material 200 (such as metal aluminum), the evaporation container is preheated to make the temperature inside the evaporation container uniform.

[0042] Then, the evaporation raw material 200 is transported into the evaporation container, and the evaporation raw material 200 is heated before reaching the bottom of the evaporation container, so that the solid evaporation raw material 200 is melted into liquid before reaching the bottom of the evaporation container. The liquid evaporation raw material 200 can drip on the bottom of the evaporation container, and as the amount of the liquid evaporation raw material 200 dripping gradually increases, the liquid evaporation raw material 200 will gradually spread around until it covers the entire bottom of the evaporation container.

[0043] Since the evaporation container has been preheated to a temperature t1, which is greater than the melting point of the evaporation raw material 200, the evaporation raw material 200 can still maintain a liquid state after dripping into the evaporation container, which facilitates the evaporation raw material 200 to spread around, and also avoids a large amount of heat loss of the evaporation raw material 200 causing energy waste. Furthermore, the temperature t1 is less than the boiling point of the evaporation raw material 200, so that when the liquid evaporation raw material 200 drips into the evaporation container and when the evaporation raw material 200 spreads around, it will not boil and splash due to contact with the bottom wall of the evaporation container that is not wetted and has too high a temperature.

[0044] When the liquid evaporation raw material 200 covers the bottom of the evaporation container, the temperature of the evaporation container is raised to temperature t2. Temperature t2 is greater than the boiling point of the evaporation raw material 200. The heating process should be carried out slowly and can be completed in multiple times to ensure more precise temperature control and avoid excessive heating or severe uneven temperature of the evaporation container due to rapid temperature changes.

[0045] Since the temperature t2 is greater than the boiling point of the evaporation raw material 200, the liquid evaporation raw material 200 in the evaporation container will gradually evaporate, and the gaseous particles generated by evaporation will fly to the surface of the substrate, and deposit, condense, nucleate and grow on the substrate, eventually forming a solid film, thereby completing the coating process.

[0046] It should be noted that under certain conditions such as vacuum, the evaporation raw material 200 may still be able to evaporate and gasify without reaching the boiling point temperature. In step S100 of the embodiment of the present application, the "boiling point temperature of the evaporation raw material" actually refers to: under the actual evaporation environment, the lowest temperature at which the evaporation raw material 200 can evaporate for coating. In step S300, in the process of "further heating the evaporation raw material at the bottom of the evaporation container to evaporate the evaporation raw material", it is only necessary to allow the evaporation raw material 200 to evaporate to meet the coating conditions, and the specific temperature can be determined according to the actual coating environment and process requirements.

[0047] During the evaporation process, since the liquid evaporation raw material 200 has been evenly spread, the evaporation rates of various parts in the evaporation container are substantially equal, thereby avoiding the problem of uneven coating thickness.

[0048] During the evaporation process, solid evaporation raw material 200 may be directly added into the evaporation container, and the high temperature of the evaporation container may be used to melt the solid evaporation raw material 200 so as to replenish the loss of liquid evaporation raw material 200 .

[0049] The present application heats the evaporation raw material 200 so that the evaporation raw material 200 melts into liquid before reaching the bottom of the evaporation container, and the liquid evaporation raw material 200 can drip on the bottom wall of the preheated evaporation container and gradually spread to the surroundings. Since the temperature of the preheated evaporation container is uniform and the temperature is greater than the melting point of the evaporation raw material 200 and less than the boiling point of the evaporation raw material 200, the probability of splashing of the liquid evaporation raw material 200 during dripping and spreading is greatly reduced, and the temperature higher than the melting point also facilitates the flow and spreading of the evaporation raw material 200, avoiding the accumulation of the evaporation raw material 200. When the liquid evaporation raw material 200 completely covers the bottom of the evaporation container, the evaporation raw material 200 in the evaporation container is heated to evaporate the evaporation raw material 200. The present application effectively solves the problem of poor coating quality caused by uneven distribution of the evaporation raw material 200 and splashing of the evaporation raw material 200.

[0050] It should be noted that the "bottom" in the above step S300 "when the melted evaporation raw material completely covers the entire bottom of the evaporation container" actually refers to the size of the internal space of the evaporation container that the liquid evaporation raw material 200 needs to occupy during the evaporation process of the evaporation raw material 200. Specifically, during the evaporation process, in order to prevent the liquid evaporation raw material 200 from overflowing the evaporation container, the evaporation raw material 200 in the evaporation container should be controlled to be within a reasonable range. Assuming that the evaporation raw material 200 is only allowed to occupy a maximum of three quarters of the space in the evaporation container, the "bottom" referred to above should refer to three quarters or even more than three quarters of the space in the evaporation container. This ensures that during the evaporation process, no liquid evaporation raw material 200 will come into contact with the high-temperature and unwetted inner wall of the evaporation container, thereby avoiding splashing.

[0051] like Figure 2 and Figure 3 As shown, based on the above evaporation method, an embodiment of the present application provides an evaporation boat, which can be used as an evaporation container. The evaporation boat includes a mounting seat 1, a boat body 2, a first heating component 3 and a second heating component 4.

[0052] Specifically, a molten pool 21 for accommodating the evaporation raw material 200 is provided on the top of the boat body 2. The boat body 2 can adopt a cubic structure to facilitate production and manufacturing. The upper end of the molten pool 21 is open to facilitate the entry and exit of the evaporation raw material 200. The cross-section of the molten pool 21 is rectangular. For example, the molten pool 21 can adopt a cubic structure or a wide-upper-narrow-lower structure. When the molten pool 21 is a cubic structure, preparation is more convenient; when the molten pool 21 is a wide-upper-narrow-lower structure, the narrower bottom can be quickly wetted by the evaporation raw material 200, shortening the spreading time of the evaporation raw material 200 so as to quickly enter the evaporation process.

[0053] The mounting seat 1 is used to support the boat body 2. The mounting seat 1 can be made of high temperature resistant and insulating ceramic, and the specific material can be alumina. A slide groove 11 is horizontally arranged on the top of the mounting seat 1, and the boat body 2 can be slidably arranged in the slide groove 11. A limiting portion 111 for limiting the boat body 2 is arranged on the top of the inner wall of the slide groove 11, so that the boat body 2 can only slide along the extension direction of the slide groove 11.

[0054] At least one side of the slide groove 11 extends to the edge of the mounting seat 1 , so that the boat body 2 can slide out of the slide groove 11 and then be separated from the mounting seat 1 .

[0055] like Figure 3 and Figure 4 As shown, in some embodiments, both opposite ends of the slide groove 11 extend to the edge of the mounting seat 1 , so that the boat body 2 can slide into or out of the slide groove 11 from any end of the slide groove 11 .

[0056] In other embodiments, one side of the slide groove 11 extends to the edge of the mounting seat 1, and the other side does not extend to the edge of the mounting seat 1. The boat body 2 can slide into the slide groove 11 from one end of the slide groove 11 located at the edge of the mounting seat 1 until the boat body 2 abuts against the other end of the slide groove 11, thereby completing the assembly of the boat body 2 and the mounting seat 1.

[0057] The first heating assembly 3 is used to heat the boat body 2 so as to heat the boat body 2 to a temperature t1 or t2.

[0058] like Figure 4 As shown, the first heating assembly 3 includes a resistance heating wire 31 and an electrode 32. The electrode 32 includes a positive electrode and a negative electrode, both of which are connected to the resistance heating wire 31. By energizing the electrode 32, the resistance heating wire 31 can be heated, thereby heating the boat 2.

[0059] The material of the resistance heating wire 31 can be metal tungsten. The resistance heating wire 31 can be arranged in a wave shape to ensure that each part of the boat body 2 can be heated evenly.

[0060] like Figure 4 As shown, a placement groove 12 is provided on the bottom wall of the slide groove 11, and the shape and depth of the placement groove 12 are adapted to the resistance heating wire 31. The resistance heating wire 31 is arranged in the placement groove 12 and can abut against the bottom of the boat body 2 placed in the slide groove 11. The contact between the resistance heating wire 31 and the boat body 2 can improve the heat transfer efficiency and reduce heat loss.

[0061] Furthermore, a flexible heat conductive member may be filled between the resistance heating wire 31 and the boat body 2, and the deformability of the flexible heat conductive member may be used to fill the gap between the resistance heating wire 31 and the boat body 2, so as to avoid uneven temperature due to the boat body 2 not being fully fitted with the resistance heating wire 31. The flexible heat conductive member may be made of a material with good thermal conductivity such as graphite paper.

[0062] The evaporation boat in the current related technology contains a conductive component. The evaporation boat is usually directly connected to the electrode and can generate heat when the electrode is powered. However, this heating method will cause the temperature of the evaporation boat to change too quickly, which is not convenient for fine temperature control. Once problems such as voltage fluctuations occur, it is likely to cause the temperature of the evaporation boat to deviate from the set temperature in a short period of time, causing the evaporated raw material 200 to splash. The embodiment of the present application transfers heat to the boat body 2 through the heating resistance heating wire 31, which can reduce the impact of voltage fluctuations on the temperature fluctuation of the boat body 2 and reduce the probability of evaporation raw material 200 splashing.

[0063] Furthermore, when the evaporation boat in the related art heats the evaporation raw material 200, the liquid evaporation raw material 200 may contact the electrode, causing the evaporation raw material 200 to conduct electricity and form a lightning-shaped current channel, thereby causing the liquid evaporation raw material 200 to boil and splash. In the present application, the boat body 2 is heated by the first heating component 3, so that the boat body 2 does not need to be directly connected to the electrode 32, thereby reducing the probability of the evaporation raw material 200 contacting the electrode 32.

[0064] Furthermore, since the embodiment of the present application does not require direct heating of the boat body 2 by electricity, the electrical conductivity of the boat body 2 does not need to be considered in the selection of the material of the boat body 2, and the material selection range is wider and the applicability is better. From the perspective of safety, the boat body 2 can be made of insulating materials to reduce the probability of boiling and splashing of the evaporation raw material 200 due to electricity. For example, a material with good thermal conductivity such as aluminum nitride can be used as the raw material of the boat body 2. One of the reasons for selecting aluminum nitride as the raw material of the boat body 2 is: The evaporation boats commonly used in the related art mainly include two-component evaporation boats of boron nitride and titanium diboride and three-component evaporation boats of boron carbide, aluminum nitride and titanium diboride. However, when the evaporation raw material 200 is metallic aluminum, boron nitride and boron carbide will react with the aluminum liquid, thereby corroding the evaporation boat, shortening the service life of the boat body 2, and easily causing aluminum liquid to splash when reacting with aluminum liquid. By using aluminum nitride to make the boat body 2, it is possible to avoid aluminum liquid corroding the boat body 2, extend the service life of the boat body 2, save costs, and effectively reduce the probability of aluminum liquid splashing, thereby improving the coating quality.

[0065] like Figure 2 As shown, the second heating component 4 is disposed above the molten pool 21 and is used to melt the evaporation raw material 200. The second heating component 4 may be an induction coil. The evaporation raw material 200 is heated by the energized induction coil, so that the evaporation raw material 200 does not need to contact with other objects during the melting process, thereby reducing the probability of the evaporation raw material 200 splashing or being contaminated.

[0066] In some embodiments, the evaporation boat further includes a flattening assembly (not shown in the figure), which includes a flattening member and a driving assembly connected to each other, and the flattening member is at least partially located in the molten pool 21. When the liquid evaporation raw material 200 drips into the molten pool 21 and gradually spreads to the surroundings, the driving assembly can drive the flattening member to move slowly to flatten the melted evaporation raw material 200, shortening the time for the evaporation raw material 200 to cover the bottom of the molten pool 21, thereby accelerating the coating efficiency.

[0067] The driving assembly may include a mounting frame, a first cylinder and a clamping member. The clamping member is used to clamp the paving member, and by clamping different parts of the paving member, the position of the paving member can be adjusted. The clamping member may be a conventional clamp or a clamping claw. The first cylinder is mounted on the mounting frame, and the first cylinder is connected to the clamping member to drive the clamping member and the paving member to move.

[0068] The material of the paving piece is the same as that of the evaporation raw material 200. For example, when the evaporation raw material 200 is aluminum, the paving piece can be an aluminum plate, so that even if the paving piece partially melts during the paving process, it will not contaminate the evaporation raw material 200, and can also replenish the loss of the liquid evaporation raw material 200.

[0069] Furthermore, the driving assembly may further include a second cylinder connected to the mounting frame. After the paving process is completed, the mounting frame may be driven to move by the second cylinder, so that the paving piece is away from the boat body 2.

[0070] The following is an introduction to the working process of the evaporation boat, taking aluminum as the evaporation raw material 200: First, the boat body 2 is preheated by the first heating component 3 so that the temperature of the boat body 2 is higher than the melting point of aluminum but lower than the boiling point of aluminum. Then, the aluminum wire is fed into the molten pool 21 of the boat body 2 by the wire feeding mechanism. Before reaching the molten pool 21, the aluminum wire is heated and melted by the second heating component 4. The molten aluminum drops into the molten pool 21 and spreads around. The spreading process can be accelerated by the flattening component. After the bottom of the molten pool 21 is completely wetted by the aluminum liquid, the boat body 2 is further heated by the first heating component 3 to evaporate the aluminum liquid in the molten pool 21, thereby completing the coating process.

Claims

1. An evaporation method, characterized in that: The following steps are involved: preheating the evaporation container to a temperature t1, wherein the temperature t1 is greater than the melting point of the evaporation raw material (200) and less than the boiling point of the evaporation raw material (200); heating the evaporation raw material (200) to melt, so that the melted evaporation raw material (200) drips into the evaporation container; When the melted evaporation raw material (200) completely covers the entire bottom of the evaporation container, the evaporation raw material (200) at the bottom of the evaporation container is further heated, thereby evaporating the evaporation raw material (200).

2. An evaporation boat, characterized in that: include: The boat body (2) is provided with a molten pool (21); A first heating component (3) used for heating the boat body (2); The second heating component (4) is disposed above the molten pool (21) and is used to melt and evaporate the raw material (200).

3. The evaporation boat according to claim 2, characterized in that: The boat body (2) is an insulating component.

4. The evaporation boat according to claim 3, characterized in that: The boat body (2) is made of aluminum nitride.

5. The evaporation boat according to claim 2, characterized in that: The evaporation boat further comprises a mounting seat (1), a slide groove (11) being provided on the top of the mounting seat (1), at least one side of the slide groove (11) extending to the edge of the mounting seat (1), and the boat body (2) being slidably disposed in the slide groove (11).

6. The evaporation boat according to claim 5, characterized in that: The first heating component (3) comprises a resistance heating wire (31) and an electrode (32); A placement groove (12) is provided on the bottom wall of the slide groove (11), and the resistance heating wire (31) is arranged in the placement groove (12) and abuts against the bottom of the boat body (2); The electrode (32) is connected to the resistance heating wire (31).

7. The evaporation boat according to claim 6, characterized in that: The evaporation boat further comprises a flexible heat-conducting member, wherein the flexible heat-conducting member is arranged between the resistance heating wire (31) and the boat body (2).

8. The evaporation boat according to claim 2, characterized in that: The evaporation boat also includes a flattening assembly, which includes a flattening member and a driving assembly connected to each other, wherein the flattening member is at least partially located in the molten pool (21), and the driving assembly is used to drive the flattening member to move so as to flatten the melted evaporation raw material (200).

9. The evaporation boat according to claim 8, characterized in that: The material of the flattening piece is the same as that of the evaporation raw material (200).

10. The evaporation boat according to claim 2, characterized in that: The second heating component (4) comprises an induction coil.

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