Evaporation apparatus and evaporation method

Abstract

The present application discloses an evaporation device and an evaporation method. During the evaporation of each material in the electrodes of an LED chip, for any material film layer, by rotating the quartz crystal disk in the monitoring system, one of the multiple quartz crystals on the quartz crystal disk is positioned at a preset position within the vapor opening of the evaporation system to monitor the coating process of the material film layer. Different material film layers correspond to different quartz crystals, so as to avoid the differences in quartz crystal monitoring of the film layer caused by differences in material density, stress, etc. of different material film layers, improve the monitoring accuracy of the quartz crystal, enhance the uniformity and stability of each material film layer formed by evaporation in the LED chip electrode, and at the same time reduce the probability of quartz crystal frequency hopping caused by stress mismatch in quartz crystal monitoring of different material coatings, improve the reliability of the quartz crystal. Moreover, the same material film layer is monitored by the same quartz crystal, which improves the quartz crystal control accuracy and makes the evaporation uniformity and stability of the same material film layer better.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular, to an evaporation device and an evaporation method. Background Art

[0002] With the continuous development of semiconductor technology, the applications of light-emitting diodes (LEDs) are changing with each passing day, especially the rapid development of LEDs in the field of display technology. With the need for high resolution of LED displays, the size of LED chips and the pitch between chips are getting smaller and smaller.

[0003] The sizes of micro-light-emitting devices such as Mini LED and Micro LED are in the micron range. There are usually thousands of chips and tens of thousands of solder joints on each substrate. With such a huge number of solder joints, and restricted by the chip size and the pitch of the two-polarity electrodes, the size of the electrode pads is small, which brings great difficulties to the packaging and soldering of the chips. At the same time, to overcome the limitation of the discrete device size on the pitch, the chip-on-board (COB) method is mostly used, which has high requirements for stability, consistency, etc. during the operation process. Therefore, stably and reliably realizing the soldering of the chip and the substrate during the packaging process is one of the important links in the application process of micro-light-emitting devices such as Mini LED and Micro LED. Currently, the eutectic soldering technology is often used to realize the soldering of micro-light-emitting devices such as Mini LED and Micro LED to the substrate.

[0004] To improve the soldering reliability of micro-light-emitting devices such as Mini LED and Micro LED, vacuum evaporation is usually used to prepare electrodes including multi-material films at the LED chip end, and the piezoelectric effect and mass loading effect of the quartz crystal wafer are used to monitor each material film deposited by evaporation. However, the existing monitoring of each material film deposited by evaporation using a quartz crystal wafer has poor accuracy and is difficult to meet the needs of the uniformity and stability of different material films, especially the actual application needs of films with a relatively thick thickness and large stress. Summary of the Invention

[0005] To solve the above technical problems, the embodiments of the present application provide an evaporation device and an evaporation method to improve the accuracy of monitoring each material film deposited by evaporation using a quartz crystal wafer, thereby improving the uniformity and stability of each material film formed by evaporation in the LED chip electrode.

[0006] To achieve the above object, the embodiments of the present application provide the following technical solutions:

[0007] An evaporation device includes a cavity and an evaporation system, a carrier system, and a monitoring system located in the cavity;

[0008] The evaporation system includes an electron gun and a crucible. The crucible is used to carry the evaporation source, and the electron gun is used to bombard the evaporation source with an electron beam to vaporize the evaporation source. The evaporation system has a vapor opening.

[0009] The loading system is used to load the component to be coated, and the component to be coated is located within the vapor opening of the evaporation system.

[0010] The monitoring system includes a quartz crystal wafer turntable and a plurality of quartz crystal wafers located on the quartz crystal wafer turntable. The quartz crystal wafers are located on the side of the quartz crystal wafer turntable facing the evaporation system. When multi-material film layers are deposited on the component to be coated, for any material film layer, by rotating the quartz crystal wafer turntable, one of the plurality of quartz crystal wafers on the quartz crystal wafer turntable is located at a preset position within the vapor opening of the evaporation system to monitor the coating process of this material film layer. Different quartz crystal wafers correspond to different material film layers.

[0011] Optionally, the plurality of quartz crystal wafers includes at least one of an aluminum-silver alloy quartz crystal wafer and a gold quartz crystal wafer.

[0012] Optionally, the crucible includes an inner wall and an outer wall surrounding the inner wall. The material of the inner wall is metal, and the material of the outer wall is graphite.

[0013] Optionally, the evaporation system further includes a crucible turntable for placing one or more of the crucibles.

[0014] A deposition method for depositing an electrode of an LED chip using a deposition device. The electrode includes an ohmic contact layer, a reflective layer, a reflective barrier layer, a eutectic barrier layer, and a eutectic soldering layer stacked in sequence. The deposition device includes a chamber and an evaporation system, a loading system, and a monitoring system located within the chamber. The method includes:

[0015] Placing the component to be coated containing the LED chip in the loading system, and the component to be coated is located within the vapor opening of the evaporation system.

[0016] For any material film layer in the electrode of the LED chip, place the corresponding evaporation source in the crucible within the evaporation system, and by rotating the quartz crystal wafer turntable in the monitoring system, one of the plurality of quartz crystal wafers on the quartz crystal wafer turntable is located at a preset position within the vapor opening of the evaporation system to monitor the coating process of this material film layer. Different quartz crystal wafers correspond to different material film layers.

[0017] Use the electron gun in the evaporation system to bombard the corresponding evaporation source with an electron beam to deposit the corresponding evaporation source onto the component to be coated and the corresponding quartz crystal wafer, and complete the deposition of each material film layer in the electrode of the LED chip.

[0018] Optionally, for the ohmic contact layer in the electrodes of the LED chip, the corresponding evaporation source is a Ni evaporation source or a Cr evaporation source, and the crystal oscillator wafer on the crystal oscillator wafer turntable at a preset position within the vapor opening of the evaporation system is an aluminum-silver alloy crystal oscillator wafer.

[0019] Optionally, for the eutectic barrier layer in the electrodes of the LED chip, the corresponding evaporation source is a Ni evaporation source, and the crystal oscillator wafer on the crystal oscillator wafer turntable at a preset position within the vapor opening of the evaporation system is an aluminum-silver alloy crystal oscillator wafer;

[0020] Using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator wafer includes:

[0021] Using the electron gun in the evaporation system to perform n times of electron beam bombardment on the corresponding evaporation source, and the spot scanning range of each electron beam bombardment does not overlap, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator wafer in n layers, where n ≥ 2.

[0022] Optionally, during the process of the electron gun performing the n times of electron beam bombardment, the power of each electron beam bombardment is constant.

[0023] Optionally, for the eutectic soldering layer in the electrodes of the LED chip, the corresponding evaporation source is an alloy evaporation source including Sn, Ag, and Cu, and the crystal oscillator wafer on the crystal oscillator wafer turntable at a preset position within the vapor opening of the evaporation system is an aluminum-silver alloy crystal oscillator wafer;

[0024] Using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator wafer includes:

[0025] In the first time period, using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source in a constant plating rate manner, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator wafer;

[0026] In the second time period, using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source in a constant power manner, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator wafer.

[0027] Optionally, the evaporation system further includes a crucible turntable for placing a plurality of the crucibles;

[0028] Placing the corresponding evaporation source in the crucible in the evaporation system includes:

[0029] Place the corresponding evaporation source in multiple crucibles on the crucible turntable in the evaporation system;

[0030] During the evaporation coating process of the eutectic welding layer, the method further includes:

[0031] Use the electron gun in the evaporation system to simultaneously bombard the evaporation sources in multiple crucibles on the crucible turntable with electron beams, so that the evaporation sources in multiple crucibles on the crucible turntable are simultaneously evaporated onto the component to be coated and the corresponding crystal oscillator wafers.

[0032] Compared with the prior art, the above technical solution has the following advantages:

[0033] When monitoring each material film layer during evaporation coating using a crystal oscillator wafer in the prior art, the same crystal oscillator wafer is used to monitor different material film layers. However, differences in material density, stress, and evaporation coating thickness of different material film layers will result in significant differences in the piezoelectric effect and mass loading effect of the crystal oscillator wafer, making the monitoring accuracy of a single crystal oscillator wafer poor. It cannot take into account the uniformity and stability of different material film layers, and it is easy to generate frequency hopping when a single crystal oscillator wafer monitors different material film layers, with a high risk of failure. When forming a multi-material film layer by evaporation coating using the evaporation coating device provided in the embodiment of the present application, for any material film layer, by rotating the crystal oscillator wafer turntable in the monitoring system, one of the multiple crystal oscillator wafers on the crystal oscillator wafer turntable is located at a preset position within the steam opening of the evaporation system to monitor the coating process of this material film layer. Different crystal oscillator wafers correspond to different material film layers, that is, different crystal oscillator wafers are used to monitor different material film layers to avoid differences in the monitoring of the film layer by the crystal oscillator wafer caused by differences in material density, stress, etc. of different material film layers, improve the monitoring accuracy of the crystal oscillator wafer, thereby enhancing the uniformity and stability of each material film layer formed on the LED chip electrode by evaporation coating, and at the same time reducing the probability of frequency hopping of the crystal oscillator wafer caused by stress mismatch in monitoring different material coatings by the crystal oscillator wafer, thereby enhancing the reliability of the crystal oscillator wafer. And for the same material film layer, the same crystal oscillator wafer can be used for monitoring, thereby improving the crystal oscillator control accuracy and making the evaporation coating uniformity and stability of the same material film layer better. Description of the Drawings

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0035] Figure 1 It is a schematic structural diagram of the evaporation coating device provided in the embodiment of the present application;

[0036] Figure 2In the evaporation device provided by the embodiments of the present application, it is a schematic structural diagram of a crucible;

[0037] Figure 3 It is a schematic structural diagram of a multi-material film layer in the electrode of an LED chip;

[0038] Figure 4 It is a schematic flow chart of the evaporation method provided by the embodiments of the present application. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0040] In the following description, many specific details are set forth in order to fully understand the present application. However, the present application may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0041] Secondly, the present application is described in detail in conjunction with the schematic diagrams. When detailing the embodiments of the present application, for the convenience of explanation, the cross-sectional views showing the device structure will be enlarged locally out of the general proportion, and the schematic diagrams are only examples and should not limit the protection scope of the present application here. In addition, in actual production, three-dimensional spatial dimensions including length, width, and depth should be included.

[0042] As described in the background art section, the existing monitoring of each material film layer during evaporation using a crystal oscillator has poor accuracy and is difficult to meet the requirements of the uniformity and stability of different material film layers, especially the actual application requirements of film layers with a relatively thick thickness and large stress.

[0043] The inventors have found through research that the quartz crystal method for monitoring film thickness mainly utilizes two effects of the quartz crystal, namely the piezoelectric effect and the mass loading effect. However, when the existing crystal oscillator is used to monitor each material film layer during evaporation, the same crystal oscillator is used to monitor different material film layers without considering the differences in the piezoelectric effect and mass loading effect of the crystal oscillator caused by the differences in the material density, stress, and evaporation thickness of different material film layers. As a result, the monitoring accuracy of a single crystal oscillator is poor, and it is impossible to take into account the uniformity and stability of different material film layers. Moreover, the crystal oscillator is prone to frequency hopping when monitoring different material film layers, and the failure risk is high.

[0044] In view of this, the embodiments of the present application provide an evaporation device, Figure 1The structural schematic diagram of the evaporation device provided by the embodiment of the present application is shown. As Figure 1 shown, the evaporation device includes a cavity 100, an evaporation system 200, a carrying system 300, and a monitoring system 400 located within the cavity 100;

[0045] The evaporation system 200 includes an electron gun ( Figure 1 not shown in the figure) and a crucible 210. The crucible 210 is used to carry the evaporation source, and the electron gun is used to bombard the evaporation source with an electron beam to vaporize the evaporation source. The evaporation system 200 has a vapor opening AA;

[0046] The carrying system 300 is used to carry the component to be coated, and the component to be coated is located within the vapor opening AA of the evaporation system 200;

[0047] The monitoring system 400 includes a quartz crystal disk turntable 410 and a plurality of quartz crystals 420 located on the quartz crystal disk turntable 410. The quartz crystals 420 are located on the side of the quartz crystal disk turntable 410 facing the evaporation system 200. When multi-material film layers are evaporated on the component to be coated, for any material film layer, by rotating the quartz crystal disk turntable 410, one of the plurality of quartz crystals 420 on the quartz crystal disk turntable 410 is located at a preset position within the vapor opening AA of the evaporation system 200 to monitor the coating process of this material film layer. Different quartz crystals 420 correspond to different material film layers.

[0048] In the embodiment of the present application, the electron gun in the evaporation system 200 bombards the evaporation source carried in the crucible 210 with an electron beam to vaporize the evaporation source. The gas molecules of the evaporation source are ejected from the crucible and deposited on the component to be coated carried by the carrying system 300 to form a target film layer. Therefore, as Figure 1 shown, the vapor opening AA of the evaporation system 200 is the vapor opening of the evaporation source in the crucible 210 for evaporation in the evaporation system 200, and it expands at a certain angle in a conical shape starting from the evaporation source in the crucible 210 for evaporation in the evaporation system 200.

[0049] In the embodiment of the present application, the component to be coated carried by the carrying system 300 is located within the vapor opening AA of the evaporation system 200 so that the gas molecules of the evaporation source in the crucible 210 for evaporation in the evaporation system 200 can be deposited on the component to be coated carried by the carrying system 300 to form a target film layer.

[0050] In the embodiment of the present application, optionally, as Figure 1As shown, the carrier system 300 includes a plating pot 310 and a plurality of wafer trays 320 located on the plating pot. The plating pot 310 is concave, and the concave surface of the plating pot 310 faces the evaporation system 200 side. The wafer trays 320 are located on the concave surface of the plating pot 310 facing the evaporation system 200 side. The wafer trays 320 are used to carry the components to be coated, and the components to be coated can be wafers or the like. However, the specific structure of the carrier system 300 is not limited in this application, as long as the carrier system 300 is used to carry the components to be coated and the components to be coated are located within the vapor opening AA of the evaporation system 200.

[0051] It should be noted that when monitoring the target film layer during evaporation coating using a crystal oscillator wafer, the crystal oscillator wafer also needs to be located within the vapor opening AA of the evaporation system 200. This is to enable the gas molecules of the evaporation source in the crucible 210 during evaporation coating in the evaporation system 200 to be deposited onto the crystal oscillator wafer for monitoring while being deposited onto the components to be coated to form the target film layer. By monitoring the vibration frequency of the crystal oscillator wafer with the deposited material film layer, the thickness and deposition rate of the target film layer can be monitored. The thickness and deposition rate of the target film layer can be monitored through the crystal oscillator wafer because there is a certain relationship between the thickness of the film layer deposited on the crystal oscillator wafer and the attenuation of the vibration frequency of the crystal oscillator wafer, that is, the change value of the vibration frequency of the crystal oscillator wafer and the change value of the thickness of the evaporation coating material film have a proportional change relationship. Then, after setting the density of a certain evaporation coating material, the thickness and deposition rate of the evaporation coating of this material can be monitored by monitoring the change in the vibration frequency of the crystal oscillator wafer.

[0052] Therefore, in the embodiments of this application, when performing evaporation coating of any material film layer on the components to be coated, one crystal oscillator wafer 420 among the multiple crystal oscillator wafers on the crystal oscillator wafer turntable 410 is rotated to be located at a preset position within the vapor opening AA of the evaporation system 200 to monitor the thickness and deposition rate of this material film layer. Optionally, such as Figure 1As shown, the preset position is located on the central axis A0 of the steam opening AA of the evaporation system 200. Since the steam opening AA of the evaporation system 200 expands at a certain conical angle starting from the evaporation source in the crucible 210 for evaporation in the evaporation system 200, the film thickness on the inner ring of the carrier system 300 that is closer to the central axis A0 of the steam opening AA of the evaporation system 200 is larger, while the film thickness on the outer ring of the carrier system 300 that is farther from the central axis A0 of the steam opening AA of the evaporation system 200 is smaller. It is necessary to correct the film thickness monitored by the crystal oscillator wafer, so as to improve the film thickness uniformity on the inner and outer rings of the carrier system 300. When performing evaporation coating, by rotating the crystal oscillator wafer turntable 410, the crystal oscillator wafer 410 is located on the central axis A0 within the steam opening AA of the evaporation system 200, so that the film thickness monitored by the crystal oscillator wafer is equivalent to the film thickness differences at various positions on the inner ring of the carrier system 300 that is closer to the central axis A0 of the steam opening AA of the evaporation system 200, and is also equivalent to the film thickness differences at various positions on the outer ring of the carrier system 300 that is farther from the central axis A0 of the steam opening AA of the evaporation system 200. Thus, it is convenient to correct the film thickness monitored by the crystal oscillator wafer and improve the film thickness uniformity on the inner and outer rings of the carrier system 300. In practical applications, the central axis A0 of the steam opening AA of the evaporation system 200 usually coincides with the central axis of the plating pot 310 in the carrier system 300.

[0053] It should also be noted that when using the crystal oscillator wafer to monitor the target film layer during evaporation coating, the crystal oscillator wafer needs to be close to the component to be coated to prevent the coating rate and film thickness monitored by the crystal oscillator wafer from being inaccurate due to differences in distance and position. Therefore, in the embodiments of the present application, the crystal oscillator wafer turntable 410 is located on the side of the carrier system 300 away from the evaporation system 200, and the distance between the crystal oscillator wafer turntable 410 and the carrier system 300 is relatively close, so that the crystal oscillator wafer on the crystal oscillator wafer turntable 410 can be used to monitor the target film layer during evaporation coating. However, the present application does not limit this, and it depends on the specific situation. As long as the position of the crystal oscillator wafer turntable 410 enables the crystal oscillator wafer on the crystal oscillator wafer turntable 410 to monitor the target film layer during evaporation coating.

[0054] It should be further noted that, in fact, the crystal oscillator wafer turntable 410 is relatively small in area with respect to the carrier system 300, such that all the crystal oscillator wafers on the crystal oscillator wafer turntable 410 will be located within the vapor opening AA of the vapor system 200, but each crystal oscillator wafer will be blocked by a baffle. When depositing any material film layer, by rotating the crystal oscillator wafer turntable 410, one crystal oscillator wafer on the crystal oscillator wafer turntable 410 is positioned at a preset position within the vapor opening AA of the evaporation system 200, and the baffle of the crystal oscillator wafer positioned at the preset position within the vapor opening AA of the evaporation system 200 is opened, so that the crystal oscillator wafer positioned at the preset position within the vapor opening AA of the evaporation system 200 monitors the target film layer to be deposited, while the other crystal oscillator wafers on the crystal oscillator wafer turntable 410 are still blocked by the baffle.

[0055] Compared with the existing method of using a crystal oscillator wafer to monitor each material film layer during evaporation coating, where the same crystal oscillator wafer is used to monitor different material film layers, the differences in material density, stress, and evaporation coating thickness of different material film layers will result in significant differences in the piezoelectric effect and mass loading effect of the crystal oscillator wafer, making the monitoring accuracy of a single crystal oscillator wafer poor, unable to balance the uniformity and stability of different material film layers, and it is easy to generate frequency hopping when a single crystal oscillator wafer monitors different material film layers, with a high risk of failure. When using the evaporation coating apparatus provided in the embodiments of the present application to evaporate and form a multi-material film layer, for any material film layer, by rotating the crystal oscillator wafer turntable 410 in the monitoring system 400, one crystal oscillator wafer 420 among the multiple crystal oscillator wafers on the crystal oscillator wafer turntable 410 is positioned at a preset position within the vapor opening AA of the evaporation system 200 to monitor the coating process of this material film layer. Different crystal oscillator wafers correspond to different material film layers, that is, different crystal oscillator wafers are used to monitor different material film layers, so as to avoid the differences in film layer monitoring by the crystal oscillator wafer caused by differences in material density, stress, etc. of different material film layers, improve the monitoring accuracy of the crystal oscillator wafer, thereby enhancing the uniformity and stability of each material film layer formed by evaporation coating in the LED chip electrode, and at the same time reducing the probability of frequency hopping of the crystal oscillator wafer caused by stress mismatch in monitoring different material coatings by the crystal oscillator wafer, thereby enhancing the reliability of the crystal oscillator wafer. Moreover, for the same material film layer, the same crystal oscillator wafer can be used for monitoring, thereby improving the crystal oscillator control accuracy and making the evaporation coating uniformity and stability of the same material film layer better.

[0056] Based on the above embodiments, optionally, in an embodiment of the present application, the multiple crystal oscillator wafers on the crystal oscillator wafer turntable 410 include at least one of an aluminum-silver (Al / Ag) alloy crystal oscillator wafer and a gold (Au) crystal oscillator wafer. The multiple crystal oscillator wafers on the crystal oscillator wafer turntable 410 may include multiple aluminum-silver alloy crystal oscillator wafers, or may include multiple gold crystal oscillator wafers, or may simultaneously include multiple aluminum-silver alloy crystal oscillator wafers and multiple gold crystal oscillator wafers, depending on the specific situation.

[0057] It should be noted that for some material films with relatively high stress, such as the ohmic contact layer and the adhesion layer at the bottom of the electrode of an LED chip, the evaporation source used for evaporation is a Ni evaporation source or a Cr evaporation source. At this time, using an aluminum-silver alloy oscillator wafer for monitoring can improve the reliability of oscillator control compared to using a gold oscillator wafer for monitoring.

[0058] Based on any of the above embodiments, optionally, in an embodiment of the present application, the crucible 210 may be a metal crucible, that is, the crucible 210 has a metal outer wall; optionally, in another embodiment of the present application, as Figure 2 shown, the crucible 210 may include an inner wall 211 and an outer wall 212 surrounding the inner wall 211. The material of the inner wall 211 is metal, and the material of the outer wall 212 is graphite. Compared with a crucible having only a metal outer wall, the crucible 210 is provided with a graphite outer wall 212 outside the metal inner wall 211, that is, the crucible is a crucible with a graphite outer wall nested with a metal inner wall, so as to use the graphite outer wall 212 for heat dissipation, improve the heat dissipation capacity of the evaporation source in the crucible 210, and further reduce the temperature of the cavity during the evaporation process.

[0059] Optionally, the metal inner wall 211 of the crucible 210 may be made of metal materials such as W, Mo, Cu, etc., and the graphite outer wall 212 of the crucible 210 may be made of graphite materials such as graphite, graphene, SiC, etc.

[0060] Optionally, the thickness T1 of the metal inner wall 211 of the crucible 210 is less than the thickness T2 of its graphite outer wall 212, so that the heat dissipation effect of the graphite outer wall 212 on the evaporation source is better. For example, T1 / T2 < 1 / 2, T1 + T2 < 5 cm, but the present application is not limited thereto, and it depends on the specific situation.

[0061] Based on any of the above embodiments, optionally, in an embodiment of the present application, as Figure 1 shown, the evaporation system 200 further includes a crucible turntable 220 for placing one or more crucibles 210.

[0062] It should be noted that the evaporation source that a single crucible can hold is limited. As the film coating progresses, the evaporation source in the crucible is continuously consumed, and the liquid level of the evaporation source in the crucible gradually drops. As the liquid level of the evaporation source in the crucible gradually drops, the kinetic energy of the electron beam of the electron gun bombarding the liquid level of the evaporation source in the crucible also gradually decreases. Then, if a constant coating rate method is to be used for film coating, it is necessary to continuously increase the power of the electron gun during the film coating process, that is, the power of the electron gun fluctuates greatly, which will cause a significant increase in the temperature of the cavity 100; if a constant power method is to be used for film coating, that is, the power of the electron gun remains constant, as the evaporation source in the crucible is continuously consumed and the liquid level of the evaporation source in the crucible gradually drops, the kinetic energy of the electron beam of the electron gun bombarding the liquid level of the evaporation source in the crucible gradually decreases, resulting in a large fluctuation in the coating rate (film coating rate), which easily affects the film coating quality and further affects the product reliability.

[0063] In current vacuum evaporation coating, a single crucible is mostly used for evaporation coating. For a material film layer with a small thickness, as the film coating progresses, the liquid level of the evaporation source in the single crucible does not drop too much. Therefore, the impact is small when using a constant coating rate method or a constant power method for film coating. However, for a material film layer with a large thickness, as the film coating progresses, the liquid level of the evaporation source in the single crucible drops significantly, and the above problems will occur. In this embodiment, multiple crucibles 210 can be placed on the crucible turntable 220. Then, for a material film layer with a large thickness, multiple crucibles 210 can be placed on the crucible turntable 220, and each crucible 210 contains an evaporation source. During the evaporation coating process, the evaporation sources in the multiple crucibles 210 on the crucible turntable 220 are simultaneously evaporated onto the component to be coated and the corresponding crystal oscillator chip, which is equivalent to multiple crucibles 210 evaporating simultaneously, thereby reducing the consumption of the evaporation source in each crucible 210 and reducing the amplitude of the decrease in the liquid level of the evaporation source in each crucible 210, providing favorable conditions for evaporating a material film layer with a large thickness.

[0064] As can be seen from the foregoing, the film thickness is larger on the inner ring of the carrier system 300 that is closer to the central axis A0 of the steam opening AA of the evaporation system 200, and the film thickness is smaller on the outer ring of the carrier system 300 that is farther from the central axis A0 of the steam opening AA of the evaporation system 200. Therefore, in this embodiment, whether one crucible 210 is placed on the crucible turntable 220 or multiple crucibles 210 are placed, as Figure 1 shown, each crucible is separately equipped with a correction plate 230, and the correction plate 230 can be located above the crucible 210 to appropriately block the evaporation source in the crucible 210 from being evaporated onto the inner ring of the carrier system 300 that is closer to the central axis A0 of the steam opening AA of the evaporation system 200, thereby correcting the difference in the film thickness of the evaporated film in different regions of the carrier system 300 and improving the coating uniformity.

[0065] The embodiment of the present application also provides a vapor deposition method for forming electrodes of an LED chip by using the vapor deposition apparatus provided in any of the above embodiments. For example, Figure 3 As shown, the electrode 10 of the LED chip includes an ohmic contact layer 11, a reflective layer 12, a reflective barrier layer 13, a eutectic barrier layer 14, and a eutectic soldering layer 15 that are stacked in sequence. Among them, the ohmic contact layer 11 at the bottom layer is usually a Ni metal layer or a Cr metal layer with good adhesion to ensure the adhesion between the ohmic contact layer 11 and the underlying film layer. Moreover, the ohmic contact layer 11 also plays the roles of ohmic contact and blocking. The thickness of the ohmic contact layer 11 is usually relatively thin (tens of angstroms to hundreds of angstroms); the second-layer reflective layer 12 usually uses metal materials with high reflectivity such as Al and Ag, which can reflect the light passing through the electrode back into the chip to improve the external quantum efficiency of the chip; the third-layer reflective barrier layer 13 usually uses metal materials such as Ti and Pt to increase the temperature resistance of the electrode; the fourth-layer eutectic barrier layer 14 is usually a Ni metal layer, and the fifth-layer eutectic soldering layer 15 mostly uses Sn alloy to reduce the soldering melting point. Since the eutectic soldering layer 15 plays the roles of conducting electricity and eutectic soldering, its thickness is relatively large (several micrometers to dozens of micrometers). The eutectic barrier layer 14 uses a Ni metal layer, so that while providing a high elastic modulus to reduce the stress between metal layers, its wetting speed with the Sn alloy layer is relatively slow, and the electrode pad can still be ensured not to fall off after multiple reflows.

[0066] The inventors have found through research that the existing methods for vapor depositing each material film layer in the electrode of an LED chip have the following problems:

[0067] (1) The materials and thicknesses of the material film layers in the electrode of the LED chip are not the same. For example, the ohmic contact layer 11 that plays the roles of ohmic contact, adhesion, and blocking is a Ni metal layer or a Cr metal layer, and its thickness is relatively thin (tens of angstroms to hundreds of angstroms), while the eutectic soldering layer 15 that plays the roles of conducting electricity and eutectic soldering is a Sn alloy, and its thickness is relatively thick (several micrometers to dozens of micrometers). The thickness difference between the two is dozens or even hundreds of times. Such large differences in metal materials and thicknesses are monitored using the same quartz crystal oscillator wafer. However, the differences in material density, stress, and vapor deposition thickness of different material film layers will result in significant differences in the piezoelectric effect and mass loading effect of the quartz crystal oscillator wafer, making the monitoring accuracy of a single quartz crystal oscillator wafer poor, unable to balance the uniformity and stability of different material film layers, and it is easy to generate frequency hopping when the quartz crystal oscillator wafer monitors different material film layers, and the failure risk is high.

[0068] In view of this, the vapor deposition method provided by the embodiment of the present application uses the vapor deposition apparatus provided in any of the above embodiments to form the electrodes of the LED chip. As known from the foregoing, the vapor deposition apparatus includes a chamber 100, an evaporation system 200, a carrier system 300, and a monitoring system 400 located in the chamber 100. For example, Figure 4 As shown, and with reference to Figure 1 As shown, the method includes:

[0069] S100: Place the component to be coated containing the LED chip in the carrier system 300, and the component to be coated is located within the vapor opening AA of the evaporation system 200;

[0070] S200: For any material film layer in the electrodes of the LED chip, place the corresponding evaporation source in the crucible 210 within the evaporation system 200, and rotate the crystal oscillator disk 410 in the rotation monitoring system 400 so that one crystal oscillator 420 among the multiple crystal oscillators on the crystal oscillator disk 410 is located at a preset position within the vapor opening AA of the evaporation system 200, and monitor the coating process of this material film layer. Different crystal oscillators correspond to different material film layers;

[0071] S300: Use the electron gun in the evaporation system 200 to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is vaporized and deposited onto the component to be coated and the corresponding crystal oscillator 420, completing the evaporation coating of each material film layer in the electrodes of the LED chip.

[0072] In the embodiment of the present application, the electron gun in the evaporation system 200 is used to perform electron beam bombardment on the evaporation source carried in the crucible 210, so that the evaporation source is vaporized. The gas molecules of the evaporation source are ejected from the crucible and deposited onto the component to be coated carried by the carrier system 300 to form a target film layer. Therefore, as Figure 1 shown, the vapor opening AA of the evaporation system 200 is the vapor opening of the evaporation source in the crucible 210 for evaporation coating in the evaporation system 200, and it expands at a certain conical angle starting from the evaporation source in the crucible 210 for evaporation coating in the evaporation system 200.

[0073] In the embodiment of the present application, the component to be coated carried by the carrier system 300 is located within the vapor opening AA of the evaporation system 200, so that the gas molecules of the evaporation source in the crucible 210 for evaporation coating in the evaporation system 200 can be deposited onto the component to be coated carried by the carrier system 300 to form a target film layer.

[0074] In the embodiment of the present application, when evaporating and coating any material film layer in the electrodes of the LED chip, rotate the crystal oscillator disk 410 so that one crystal oscillator 420 among the multiple crystal oscillators on the crystal oscillator disk 410 is located at a preset position within the vapor opening AA of the evaporation system 200, and monitor the thickness and deposition rate of this material film layer. Optionally, as Figure 1As shown, the preset position is located on the central axis A0 of the vapor opening AA of the evaporation system 200. Since the vapor opening AA of the evaporation system 200 expands at a certain conical angle starting from the evaporation source in the crucible 210 for evaporation in the evaporation system 200, the film thickness on the inner ring of the carrier system 300 that is closer to the central axis A0 of the vapor opening AA of the evaporation system 200 is larger, while the film thickness on the outer ring of the carrier system 300 that is farther from the central axis A0 of the vapor opening AA of the evaporation system 200 is smaller. It is necessary to correct the film thickness monitored by the crystal oscillator wafer, so as to improve the film thickness uniformity on the inner ring and the outer ring of the carrier system 300. When performing evaporation coating, by rotating the crystal oscillator wafer turntable 410, the crystal oscillator wafer 410 is located on the central axis A0 within the vapor opening AA of the evaporation system 200, so that the film thickness monitored by the crystal oscillator wafer is equivalent to the film thickness difference at each point on the inner ring of the carrier system 300 that is closer to the central axis A0 of the vapor opening AA of the evaporation system 200, and is also equivalent to the film thickness difference at each point on the outer ring of the carrier system 300 that is farther from the central axis A0 of the vapor opening AA of the evaporation system 200. Thus, it is convenient to correct the film thickness monitored by the crystal oscillator wafer and improve the film thickness uniformity on the inner ring and the outer ring of the carrier system 300. In practical applications, the central axis A0 of the vapor opening AA of the evaporation system 200 usually coincides with the central axis of the plating pot 310 in the carrier system 300.

[0075] It should be noted that when using the crystal oscillator wafer to monitor the target film layer during evaporation coating, the crystal oscillator wafer needs to be close to the component to be coated to prevent the coating rate and film thickness monitored by the crystal oscillator wafer from being inaccurate due to differences in distance and position. Therefore, in the embodiment of the present application, the crystal oscillator wafer turntable 410 is located on the side of the carrier system 300 away from the evaporation system 200, and the distance between the crystal oscillator wafer turntable 410 and the carrier system 300 is relatively close, so that the crystal oscillator wafer on the crystal oscillator wafer turntable 410 can be used to monitor the target film layer during evaporation coating. However, the present application does not limit this, and it depends on the specific situation. As long as the position of the crystal oscillator wafer turntable 410 enables the crystal oscillator wafer on the crystal oscillator wafer turntable 410 to monitor the target film layer during evaporation coating.

[0076] It should also be noted that, in fact, the crystal oscillator wafer turntable 410 is relatively small in area with respect to the carrier system 300, so that all the crystal oscillator wafers on the crystal oscillator wafer turntable 410 will be located within the steam opening AA of the steam system 200, but each crystal oscillator wafer will be blocked by the baffle. When performing any material film layer in the electrodes of the LED chip, by rotating the crystal oscillator wafer turntable 410, a crystal oscillator wafer on the crystal oscillator wafer turntable 410 is located at a preset position within the steam opening AA of the evaporation system 200, and the baffle of the crystal oscillator wafer located at the preset position within the steam opening AA of the evaporation system 200 is opened, so that the crystal oscillator wafer located at the preset position within the steam opening AA of the evaporation system 200 monitors the target film layer to be evaporated, while the other crystal oscillator wafers on the crystal oscillator wafer turntable 410 are still blocked by the baffle.

[0077] Compared with the existing method of using a crystal oscillator wafer to monitor each material film layer in the electrodes of the evaporated LED chip, when monitoring different material film layers, the same crystal oscillator wafer is used for monitoring. However, the differences in material density, stress, and evaporation thickness of different material film layers will cause obvious differences in the piezoelectric effect and mass loading effect of the crystal oscillator wafer, resulting in poor monitoring accuracy of a single crystal oscillator wafer. It is impossible to balance the uniformity and stability of different material film layers, and it is easy to generate frequency hopping when a single crystal oscillator wafer monitors different material film layers, with a high risk of failure. When using the evaporation method provided by the embodiments of the present application to evaporate and form multiple material film layers in the electrodes of the LED chip, for any material film layer, by rotating the crystal oscillator wafer turntable 410 in the monitoring system 400, one crystal oscillator wafer 420 among the multiple crystal oscillator wafers on the crystal oscillator wafer turntable 410 is located at a preset position within the steam opening AA of the evaporation system 200 to monitor the coating process of this material film layer. Different crystal oscillator wafers correspond to different material film layers, that is, different crystal oscillator wafers are used to monitor different material film layers to avoid the differences in the monitoring of the film layer by the crystal oscillator wafer caused by the differences in material density, stress, etc. of different material film layers, improve the monitoring accuracy of the crystal oscillator wafer, thereby enhancing the uniformity and stability of each material film layer formed by evaporation in the electrodes of the LED chip, and at the same time reducing the probability of frequency hopping of the crystal oscillator wafer caused by the stress mismatch of different material coatings monitored by the crystal oscillator wafer, thereby enhancing the reliability of the crystal oscillator wafer. Moreover, for the same material film layer, the same crystal oscillator wafer can be used for monitoring, thereby improving the crystal oscillator control accuracy and making the evaporation uniformity and stability of the same material film layer better.

[0078] It should be noted that in actual applications, before the evaporation starts, the chamber 100 needs to be evacuated to below 5.0e - 1 torr by a mechanical pump first, and then the vacuum chamber is evacuated to below 2.0e - 6 torr by a cold pump. After the chamber environment is stable for a period of time, the evaporation starts.

[0079] The inventor also found that the existing methods for evaporating each material film layer in the electrodes of the LED chip also have the following problems:

[0080] (2) To improve the welding reliability, the electrodes of the LED chip are very thick, and the eutectic welding layer 15 is usually greater than 8 μm. Coupled with other film layers, the entire electrode evaporation process takes a long time (more than 6 h). As the coating thickness increases, the cavity temperature rises rapidly. By the end of the coating, the cavity temperature can exceed 120 °C. The electrode pattern needs to be realized by a negative photoresist stripping process. The negative photoresist is prone to denaturation in a long-term high-temperature environment, resulting in difficult stripping and difficult photoresist removal.

[0081] (3) Evaporation is mostly carried out using a single crucible. However, since the evaporation sources that a single crucible can hold are limited, when evaporating a relatively thick film layer, as the coating progresses, the evaporation sources in the crucible are continuously consumed, and the liquid level of the evaporation sources in the crucible gradually drops. If a constant coating rate is used for coating, it is necessary to continuously increase the power of the electron gun during the coating process, that is, the power of the electron gun fluctuates greatly, which will cause a significant increase in the temperature of the cavity 100; if a constant power is used for coating, that is, the power of the electron gun remains constant, the coating rate (coating speed) will fluctuate greatly, affecting the coating quality and further affecting the product reliability.

[0082] Based on this, the evaporation process of each material film layer in the electrode of the LED chip will be described below.

[0083] Optionally, in an embodiment of the present application, for the ohmic contact layer 11 in the electrode 10 of the LED chip, the corresponding evaporation source is a Ni evaporation source or a Cr evaporation source, and the quartz crystal 420 at a preset position on the quartz crystal turntable 410 in the steam opening AA of the evaporation system 200 is an aluminum-silver alloy quartz crystal.

[0084] In this embodiment, it is necessary to rotate the quartz crystal turntable 410 in the rotation monitoring system 400 to place the aluminum-silver alloy quartz crystal at a preset position in the steam opening AA of the evaporation system 200 to monitor the coating process of the ohmic contact layer 11. Since the ohmic contact layer 11 needs to ensure the adhesion to the underlying film layer, the ohmic contact layer 11 is a Ni metal layer or a Cr metal layer with good adhesion. At this time, using an aluminum-silver alloy quartz crystal for monitoring can improve the reliability of quartz crystal control compared with the existing method of using a gold quartz crystal for monitoring.

[0085] In this embodiment, the crucible 210 can be a tungsten crucible for holding a Ni evaporation source or a Cr evaporation source, or it can also be Figure 2 the crucible with a graphite outer wall nested with a metal inner wall as shown, to utilize the graphite outer wall 212 for heat dissipation, improve the heat dissipation capacity of the evaporation source in the crucible 210, and also avoid the sharp rise in the cavity temperature caused by the increase in evaporation power as the evaporation source is consumed.

[0086] In this embodiment, since the ohmic contact layer 11 is the first layer in the electrode 10 of the LED chip, a constant plating rate method can be used for film deposition. At this time, the film deposition rate can be increased, and the temperature in the cavity 100 is not high.

[0087] Specifically, an Al / Ag oscillator wafer 1 is used to monitor the film deposition to prepare the underlying high-stress ohmic contact layer 11 in the electrode 10 of the LED chip. The initial frequency of the Al / Ag oscillator wafer 1 is 6 MHz to 10 MHz. A tungsten crucible is selected to hold the evaporation source, and the evaporation source is a Ni evaporation source or a Cr evaporation source. The film deposition is carried out by a constant plating rate method. First, the evaporation source is preheated with a preheating power of Pa1 for 30 s to 60 s. Secondly, the evaporation source is pre-melted with a pre-melting power of Pa2 for 30 s to 5 min. Then, after pre-melting and before evaporation, a steady state is reached, and the power at this time is Pa3. A constant plating rate Ra1 is set, and a plating thickness Ta1 is set. Among them, when setting the power Pa3, it is necessary to ensure that after the baffle is opened, the time for the plating rate to rise from 0 to Ra1 is less than 30 s, and at this time, the power fluctuation corresponding to the constant plating rate is within the range of Pa3 ± 2%, and the plating rate fluctuation is within the range of Ra1 ± 5%. After that, the ohmic contact layer 11 is evaporated at the constant plating rate Ra1.

[0088] Optionally, in an embodiment of the present application, for the reflective layer 12 in the electrode 10 of the LED chip, the corresponding evaporation source is an Al evaporation source or an Ag evaporation source, and the oscillator wafer 420 at a preset position within the vapor opening AA of the evaporation system 200 on the oscillator wafer turntable 410 is a gold oscillator wafer.

[0089] In this embodiment, it is necessary to rotate the oscillator wafer turntable 410 in the rotation monitoring system 400 to switch another oscillator wafer (gold oscillator wafer) different from the one used when evaporating the ohmic contact layer 11 to a preset position within the vapor opening AA of the evaporation system 200 to monitor the film deposition process of the reflective layer 12.

[0090] In this embodiment, since the reflective layer 12 needs to reflect the light passing through the electrode back into the chip interior to improve the external quantum efficiency of the chip, the corresponding evaporation source is an Al evaporation source or an Ag evaporation source to form a reflective layer 12 with a high reflectivity.

[0091] In this embodiment, the crucible 210 can adopt Figure 2 the crucible with a graphite outer wall nested with a metal inner wall as shown, so as to utilize the graphite outer wall 212 for heat dissipation, improve the heat dissipation capacity of the evaporation source in the crucible 210, and also avoid the sharp rise in the cavity temperature caused by the increase in evaporation power as the evaporation source is consumed. Since the reflective layer 12 is the second layer in the electrode of the LED chip, at this time, the temperature in the cavity 100 is not high yet, so other metal crucibles can also be used for the crucible.

[0092] In this embodiment, since the reflective layer 12 is the second layer in the electrode 10 of the LED chip, a constant deposition rate method can be used for coating. At this time, the coating rate can be increased, and the temperature in the cavity 100 is not high.

[0093] Specifically, switch the quartz crystal wafer and use the Au quartz crystal wafer 2 to monitor the coating to prepare the reflective layer 12. The initial frequency of the Au quartz crystal wafer 2 is 5 MHz to 6 MHz. Select Figure 2 The crucible with a graphite outer wall nested with a metal inner wall as shown is used to hold the evaporation source. The evaporation source is an Al evaporation source or an Ag evaporation source, and the coating is carried out by a constant deposition rate method. First, preheat the evaporation source, the preheating power is Pb1, and the preheating lasts for 30 s to 60 s; secondly, pre-melt the evaporation source, the pre-melting power is Pb2, and the pre-melting time is 30 s to 5 min; then, after pre-melting and before evaporation, reach a steady state, at this time the power is Pb3, set a constant deposition rate Rb1, and set the coating thickness Tb1. Among them, setting the power Pb3 needs to ensure that after the baffle is opened, the time for the deposition rate to rise from 0 to Rb1 is less than 30 s, and at this time the power fluctuation corresponding to the constant deposition rate is within the range of Pb3 ± 2%, and the deposition rate fluctuation is within the range of Rb1 ± 5%; afterwards, deposit the reflective layer 12 at the constant deposition rate Rb1.

[0094] Optionally, in an embodiment of the present application, for the reflective barrier layer 13 in the electrode 10 of the LED chip, the corresponding evaporation source is a Ti evaporation source or a Pt evaporation source, and the quartz crystal wafer 420 at a preset position on the quartz crystal wafer turntable 410 in the steam opening AA of the evaporation system 200 is a gold quartz crystal wafer.

[0095] In this embodiment, it is necessary to rotate the quartz crystal wafer turntable 410 in the rotation monitoring system 400 to switch another quartz crystal wafer (gold quartz crystal wafer) different from the quartz crystal wafer used when depositing the ohmic contact layer 11 and the reflective layer 12 to be located at a preset position in the steam opening AA of the evaporation system 200 to monitor the coating process of the reflective barrier layer 13.

[0096] In this embodiment, the crucible 210 can adopt Figure 2 The crucible with a graphite outer wall nested with a metal inner wall as shown to utilize the graphite outer wall 212 for heat dissipation, improve the heat dissipation capacity of the evaporation source in the crucible 210, and can also avoid the sharp rise in the cavity temperature caused by the increase in the evaporation power as the evaporation source is consumed. Since the reflective barrier layer 13 is the third layer in the electrode of the LED chip, at this time, the temperature in the cavity 100 is not too high, so other metal crucibles can also be used for the crucible.

[0097] In this embodiment, since the reflective barrier layer 13 is the third layer in the electrode 10 of the LED chip, a constant deposition rate method can be used for coating. At this time, the coating rate can be increased, and the temperature in the cavity 100 is not too high.

[0098] Specifically, for switching the crystal oscillator wafer, an Au crystal oscillator wafer 3 is used to monitor the coating to prepare the reflection barrier layer 13. The initial frequency of the Au electrode crystal oscillator wafer 3 is 6 MHz to 10 MHz. A metal crucible is selected to hold the evaporation source, and the evaporation source is a Ti evaporation source or a Pt evaporation source. The constant deposition rate coating method is adopted. First, preheat the evaporation source with a preheating power of Pc1 for 30 s to 60 s. Secondly, pre-melt the evaporation source with a pre-melting power of Pc2 for 30 s to 5 min. Then, reach a steady state after pre-melting and before evaporation, with a power of Pc3 at this time. Set a constant deposition rate Rc1 and a coating thickness Tc1. Among them, when setting the power Pc3, it is necessary to ensure that after the baffle is opened, the time for the deposition rate to rise from 0 to Rc1 is less than 30 s, and at this time, the power fluctuation corresponding to the constant deposition rate is within the range of Pc3 ± 2%, and the deposition rate fluctuation is within the range of Rc1 ± 5%. After that, deposit the reflection barrier layer 13 at the constant deposition rate Rc1.

[0099] Optionally, in an embodiment of the present application, for the eutectic barrier layer 14 in the electrode 10 of the LED chip, the corresponding evaporation source is a Ni evaporation source, and the crystal oscillator wafer 420 at a preset position within the vapor opening AA of the evaporation system 200 on the crystal oscillator wafer turntable 410 is an aluminum-silver alloy crystal oscillator wafer;

[0100] Using an electron gun in the evaporation system 200 to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is deposited on the component to be coated and the corresponding crystal oscillator wafer 420 includes:

[0101] S310: Using an electron gun in the evaporation system 200 to perform n times of electron beam bombardment on the corresponding evaporation source, and the spot scanning ranges of each electron beam bombardment do not overlap, so that the corresponding evaporation source is deposited on the component to be coated and the corresponding crystal oscillator wafer 420 in n layers, where n ≥ 2.

[0102] In this embodiment, it is necessary to rotate the crystal oscillator wafer turntable 410 in the rotation monitoring system 400 to switch another crystal oscillator wafer (aluminum-silver alloy crystal oscillator wafer) different from the crystal oscillator wafer used when depositing the ohmic contact layer 11, the reflective layer 12, and the reflection barrier layer 13 to a preset position within the vapor opening AA of the evaporation system 200 to monitor the coating process of the eutectic barrier layer 14.

[0103] It should be noted that since Ni metal has magnetism, when the electron gun bombards the Ni evaporation source with electron beams, a drill hole will be formed at the bombardment site, and other Ni materials outside the bombardment site cannot fill the drill hole due to magnetic repulsion, which can easily cause the crucible to be punctured and damaged. Therefore, in this embodiment, the eutectic barrier layer is deposited in a multi-spot and multi-layer manner. Specifically, the electron gun in the evaporation system 200 bombards the corresponding evaporation source with electron beams n times, and the spot scanning range of each electron beam bombardment does not overlap, so that the corresponding evaporation source is deposited on the component to be coated and the corresponding crystal oscillator 420 in n layers, so as to avoid the formation of drill holes in the Ni evaporation source and cause the crucible to be punctured and damaged.

[0104] In this embodiment, the eutectic barrier layer 14 can be deposited in a manner of constant deposition rate, or can be deposited in a manner of constant power. Preferably, during the n times of electron beam bombardment by the electron gun, the power of each electron beam bombardment is constant, that is, the eutectic barrier layer 14 is deposited in a manner of constant power. This is because the eutectic barrier layer 14 is the fourth layer in the electrode 10 of the LED chip, and the cavity temperature has gradually increased. If the coating is carried out in a manner of constant deposition rate, the power of the electron gun needs to gradually increase during each electron beam bombardment, which will further exacerbate the increase of the cavity temperature. However, when the coating is carried out in a manner of constant power, the cavity temperature rises slowly and does not become too high.

[0105] In this embodiment, when the electron gun conducts each electron beam bombardment, it needs to go through the processes of preheating the evaporation source, pre-melting, steady state after pre-melting and before evaporation, and evaporation.

[0106] In this embodiment, in order to prevent damage to the crucible, the total spot scanning range of the n times of electron beam bombardment does not exceed 2 / 3 of the inner diameter of the crucible, but this application does not limit this, as long as the total spot scanning range of the n times of electron beam bombardment will not cause damage to the crucible.

[0107] In this embodiment, the crucible 210 can adopt Figure 2 the crucible with a graphite outer wall nested with a metal inner wall as shown, so as to utilize the graphite outer wall 212 for heat dissipation, improve the heat dissipation capacity of the evaporation source in the crucible 210, and also avoid the sharp rise of the cavity temperature caused by the increase of the evaporation power as the evaporation source is consumed. Of course, other metal crucibles can also be used, depending on the specific situation.

[0108] Specifically, for the switching crystal oscillator chip, an Al / Ag alloy crystal oscillator chip 4 is used to monitor the coating to prepare the eutectic barrier layer 14. The initial frequency of the Al / Ag alloy crystal oscillator chip 4 is 5M - 6MHz, and the evaporation source is a Ni evaporation source. During the preparation process, single crucible multi-spot layer-by-layer coating is adopted, and the number of layers n ≥ 2, and the thickness of each layer is equal. During the coating process, the coating is continuously heated, and the temperature is controlled at 50°C - 80°C. This metal film layer is coated by a constant power method. When coating each layer, first, preheat the evaporation source, with the preheating power being Pd1 and the preheating lasting for 30s - 60s; secondly, pre-melt the evaporation source, with the pre-melting power being Pd2, Pd2 > Pd1, and the pre-melting time being 30s - 5min; then, after pre-melting and before evaporation, reach a steady state, at this time the power is Pd3, Pd3 < Pd2. After that, set the rated power to Pd4, Pd1 < Pd4 < Pd3 < Pd2, and the fluctuation of Pd4 is less than ±0.5%. The coating rate when reaching the rated power Pd4 is Rd1. When coating each layer, the spots bombarded by the electron beam do not overlap. During the entire coating process, the coating rate Rd1 fluctuates within the range of Rd1 ± 10%. Repeat n times to reach the set coating thickness Td1, and the total scanning range of the n spot positions is within 2 / 3 of the inner diameter circle of the crucible.

[0109] It can be seen that the eutectic barrier layer 14 adopts multi-spot multi-layer evaporation coating. The multi-spots can evenly evaporate the surface of the evaporation source, avoiding the breakdown and damage of the crucible caused by the drilling of the Ni magnetic attachment evaporation source. And the rated power coating method is adopted to reduce the temperature fluctuation in the cavity during the coating process and reduce the stress generated during the film layer preparation process.

[0110] Optionally, in an embodiment of the present application, for the eutectic soldering layer 15 in the electrode 10 of the LED chip, the corresponding evaporation source is an alloy evaporation source including Sn, Ag, and Cu, and the crystal oscillator chip 420 at a preset position on the crystal oscillator chip turntable 410 within the steam opening AA of the evaporation system 200 is an aluminum-silver alloy crystal oscillator chip;

[0111] Using the electron gun in the evaporation system 200 to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator chip 420 includes:

[0112] In the first time period, use the electron gun in the evaporation system 200 to perform electron beam bombardment on the corresponding evaporation source at a constant coating rate, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator chip 420;

[0113] In the second time period, use the electron gun in the evaporation system 200 to perform electron beam bombardment on the corresponding evaporation source at a constant power, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding crystal oscillator chip 420.

[0114] In this embodiment, it is necessary to rotate the crystal oscillator wafer turntable 410 in the rotation monitoring system 400 to switch another crystal oscillator wafer (aluminum-silver alloy crystal oscillator wafer) different from the crystal oscillator wafer used when evaporating the ohmic contact layer 11, the reflective layer 12, the reflective barrier layer 13, and the eutectic barrier layer 14 to a preset position within the vapor opening AA of the evaporation system 200, and monitor the coating process of the eutectic solder layer 15.

[0115] In this embodiment, for the eutectic solder layer 15 in the electrodes of the LED chip, the corresponding evaporation source is a Sn alloy evaporation source, including Sn metal, Ag metal, and Cu metal, where the weight percentage of Sn metal is 95% - 97%, the weight percentage of Ag metal is 2% - 3.5%, and the weight percentage of Cu metal is 0.5% - 1%.

[0116] Considering that the thickness of the eutectic solder layer 15 in the electrode 10 of the LED chip is relatively large, usually greater than 8 μm. For the evaporation coating of the eutectic solder layer 15 with such a thickness, the traditional coating method with a constant coating rate is adopted. However, as the liquid level of the evaporation source in the crucible gradually decreases, in order to maintain a constant coating rate, the power of the electron gun needs to be gradually increased, which causes the chamber temperature to rise sharply, easily resulting in the deformation of the negative photoresist for forming the electrode pattern, making it difficult to strip and remove the photoresist. Therefore, in this embodiment, a coating method combining a constant coating rate in the early stage and a constant power in the later stage is adopted for the eutectic solder layer 15, that is, in the first time period, a constant coating rate method is used for coating to ensure the coating speed, and in the subsequent second time period, a constant power method is used for coating so that the chamber temperature does not rise too fast. At this time, the coating rate decreases somewhat.

[0117] Based on the above embodiments, in an embodiment of the present application, a three-step coating method can be adopted for the eutectic solder layer 15, specifically as follows:

[0118] In the first step, a coating method with a constant coating rate is adopted, and the proportion of the coating thickness Te1 to the total thickness T of the eutectic solder layer 15 is 0.5 - 0.6.

[0119] Specifically, for the switching crystal oscillator wafer, an Al / Ag alloy crystal oscillator wafer 5 is used to monitor the coating to prepare the eutectic welding layer 15. The initial frequency of the Al / Ag alloy crystal oscillator wafer 5 is 5M - 6MHz, and the evaporation source is a Sn alloy evaporation source. First, preheat the Sn alloy evaporation source with a preheating power of Pe1 for 30s - 60s; second, pre-melt the Sn alloy evaporation source with a pre-melting power of Pe2 for 30s - 5min; then, reach a steady state after pre-melting and before evaporation, with the power at Pe3 at this time. Set a constant plating rate Re1, which is controlled within 10A / S - 15A / S, and set the plating thickness Te1. The proportion of Te1 in the total thickness T of the eutectic welding layer 15 is 0.5 - 0.6. The set power Pe3 needs to ensure that after the baffle is opened, the time for the plating rate to rise from 0 to Re1 is less than 60s, and at this time, the power corresponding to the constant plating rate fluctuates within the range of Pe3 ± 2%, and the plating rate fluctuates within the range of Re1 ± 5%; then, carry out coating at the constant plating rate Re1. When the set plating thickness Te1 is reached, the chamber temperature is lower than 50°C.

[0120] In the second step, adopt a coating method with a constant plating rate. The proportion of the coating thickness Tf1 in the total thickness T of the eutectic welding layer 15 is 0.2 - 0.3.

[0121] Specifically, first, preheat the Sn alloy evaporation source with a preheating power of Pf1 for 30s - 60s; second, pre-melt the Sn alloy evaporation source with a pre-melting power of Pf2 for 30s - 5min; then, reach a steady state after pre-melting and before evaporation, with the power at Pf3 at this time. Set a constant plating rate Rf1, which is controlled within 5A / S - 10A / S, and set the plating thickness Tf1. The proportion of Tf1 in the total thickness T of the eutectic welding layer 15 is 0.2 - 0.3. The set power Pf3 needs to ensure that after the baffle is opened, the time for the plating rate to rise from 0 to Rf1 is less than 60s, and at this time, the power corresponding to the constant plating rate fluctuates within the range of Pf3 ± 2%, and the plating rate fluctuates within the range of Rf1 ± 5%; then, carry out coating at the constant plating rate Rf1. When the set plating thickness Tf1 is reached, the chamber temperature is lower than 70°C.

[0122] In the third step, adopt a coating method with a constant power. The proportion of the coating thickness Tg1 in the total thickness T of the eutectic welding layer 15 is 0.1 - 0.3.

[0123] Specifically, first, preheat the Sn alloy evaporation source with a preheating power of Pg1 for 30 s to 60 s; second, pre-melt the Sn alloy evaporation source with a pre-melting power of Pg2 for 30 s to 5 min; then, reach a steady state after pre-melting and before evaporation, with the power at this time being Pg3. Set the rated power Pg4 and set the coating thickness Tg1. The proportion of Tg1 in the total thickness T of the eutectic solder layer 15 is 0.1 to 0.3. The set power Pg3 needs to ensure that after the baffle is opened, the time for the power to change from Pg3 to Pg4 is less than 10 s, Pg1 < Pg4 < Pg3 < Pg2, and at this time, Pg4 fluctuates within the range of Pg4 ± 0.5%. The stable coating rate when reaching the rated power Pg4 is Rg1, and the coating rate fluctuates within the range of Rg1 ± 10% during the coating process; after that, coat at the rated power Pg4. When the set coating thickness Tg1 is reached, the cavity temperature is lower than 100°C.

[0124] It should be noted that in this embodiment, the rated power Pg4 of the third-step coating is less than the power Pf3 of the coating at the constant coating rate Rf1 in the second step, and the power Pf3 of the coating at the constant coating rate Rf1 in the second step is less than the power Pe3 of the coating at the constant coating rate Re1 in the first step, that is, Pg4 < Pf3 < Pe3, so that as the coating thickness increases, the power of the electron gun gradually decreases, thereby reducing the rising speed of the cavity temperature.

[0125] It also should be noted that since the power of the electron gun gradually decreases as the coating thickness increases, that is, Pg4 < Pf3 < Pe3, therefore, the constant coating rate Rf1 of the second-step coating is less than the constant coating rate Re1 of the first-step coating, and the coating rate Rg1 at the rated power Pg4 of the third step is less than the constant coating rate Rf1 of the second-step coating, that is, Rg1 < Rf1 < Re1.

[0126] On the basis of the above embodiment, in an embodiment of the present application, as shown in Figure 1 the evaporation system 200 further includes a crucible turntable 220 for placing one or more crucibles 210. In this embodiment, a plurality of crucibles 210 are placed on the crucible turntable 220. Then, placing the corresponding evaporation source in the crucible 210 in the evaporation system 200 includes:

[0127] S210: Place the corresponding evaporation source in the plurality of crucibles 210 on the crucible turntable 220 in the evaporation system 200;

[0128] During the evaporation process of the eutectic solder layer 15, the method further includes:

[0129] S320: Use the electron gun in the evaporation system 200 to simultaneously perform electron bombardment on the evaporation sources in multiple crucibles 210 on the crucible turntable 220, so that the evaporation sources in the multiple crucibles 210 on the crucible turntable 220 are simultaneously evaporated onto the component to be coated and the corresponding crystal oscillator wafer 420.

[0130] In this embodiment, the number of crucibles 210 placed on the crucible turntable 220 is greater than or equal to 2. It can be seen that when the existing eutectic solder layer 15 is vapor-deposited, a single crucible is used to hold the evaporation source, and a high-speed vapor-deposition method with a constant deposition rate is adopted. In this embodiment, multiple crucibles are used to hold the evaporation sources simultaneously, that is, multiple evaporation sources are vapor-deposited simultaneously, and a vapor-deposition method combining a constant deposition rate in the early stage and a constant power in the later stage is adopted, that is, vapor-deposition is carried out at a low rate in multiple steps, ensuring that the power consumption of the evaporation source is stable, the temperature rise of the overall cavity environment is small, and since multiple evaporation sources are vapor-deposited simultaneously, the vapor-deposition speed will not be too slow.

[0131] As described above, the film thickness on the inner ring of the carrier system 300 that is closer to the central axis of the vapor opening AA of the evaporation system 200 is larger, while the film thickness on the outer ring of the carrier system 300 that is farther from the central axis of the vapor opening AA of the evaporation system 200 is smaller. Therefore, in this embodiment, when multiple crucibles 210 are placed on the crucible turntable 220, as Figure 1 shown, each crucible is individually equipped with a correction plate 230, which can be located above the crucible 210 to appropriately block the evaporation source in the crucible 210 from being vapor-deposited onto the inner ring of the carrier system 300 that is closer to the central axis of the vapor opening AA of the evaporation system 200, thereby correcting the difference in the vapor-deposited film thickness in different regions of the carrier system, improving the vapor-deposition uniformity, and additionally reducing the reduction amplitude of the evaporation source liquid level, providing conditions for vapor-depositing thick metal films.

[0132] Furthermore, in this embodiment, the crucible 210 can adopt Figure 2 the crucible with a graphite outer wall nested with a metal inner wall as shown, so as to use the graphite outer wall 212 for heat dissipation, improve the heat dissipation capacity of the evaporation source in the crucible 210, and avoid the sharp rise in the cavity temperature caused by the increase in the evaporation power as the evaporation source is consumed during the thick metal vapor-deposition process.

[0133] In summary, in the process of vapor deposition of each material in the electrodes of the LED chip in the vapor deposition device and the vapor deposition method provided by the embodiments of the present application, for any material film layer, by rotating the quartz crystal wafer turntable in the monitoring system, one of the multiple quartz crystal wafers on the quartz crystal wafer turntable is located at a preset position within the vapor opening of the evaporation system to monitor the coating process of the material film layer. Different quartz crystal wafers correspond to different material film layers, that is, different quartz crystal wafers are used to monitor different material film layers, so as to avoid the differences in the monitoring of the film layer by the quartz crystal wafer caused by the differences in material density, stress, etc. of different material film layers, improve the monitoring accuracy of the quartz crystal wafer, thereby improving the uniformity and stability of each material film layer formed by vapor deposition in the LED chip electrode, and at the same time reducing the probability of quartz crystal wafer frequency hopping caused by the stress mismatch of different material coatings monitored by the quartz crystal wafer, thereby improving the reliability of the quartz crystal wafer. Moreover, the same quartz crystal wafer can be used to monitor the same material film layer, thereby improving the crystal oscillator control accuracy and making the vapor deposition uniformity and stability of the same material film layer better.

[0134] Furthermore, for the ohmic contact layer with relatively high stress in the electrode of the LED chip, using an aluminum-silver alloy quartz crystal wafer for monitoring can improve the reliability of crystal oscillator control compared to using a gold quartz crystal wafer for monitoring. For the eutectic barrier layer in the electrode of the LED chip, vapor deposition is carried out in a multi-spot and multi-layer manner. The multi-spots can uniformly deposit on the surface of the evaporation source, avoiding the breakdown and damage of the crucible caused by Ni magnetic attachment to drill holes in the evaporation source, and using a rated power coating method to reduce the temperature fluctuation in the cavity during the coating process and reduce the stress generated during the film layer preparation process. For the eutectic welding layer in the electrode of the LED chip, multi-evaporation sources are used for simultaneous vapor deposition, and a coating method combining a constant deposition rate in the early stage and a constant power in the later stage is adopted, that is, vapor deposition is carried out at a multi-step low rate to ensure the stable consumption power of the evaporation source and a relatively small increase in the overall cavity environment temperature.

[0135] In addition, the crucible can be a crucible with a graphite outer wall nested with a metal inner wall to utilize the graphite outer wall for heat dissipation, improve the heat dissipation capacity of the evaporation source in the crucible, and avoid the sharp rise in the cavity temperature caused by the increase in evaporation power as the evaporation source is consumed during the thick metal vapor deposition process.

[0136] In this specification, each part is described in a combination of parallel and progressive ways. The key points of each part are the differences from other parts. For the same or similar parts among each part, reference can be made to each other.

[0137] Regarding the above description of the disclosed embodiments, the features described in each embodiment in this specification can be replaced or combined with each other, enabling those skilled in the art to implement or use this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vapor deposition method, characterized in that, The electrodes of the LED chip are formed by evaporation coating using an evaporation coating device. The electrodes include an ohmic contact layer, a reflective layer, a reflection barrier layer, a eutectic barrier layer, and a eutectic soldering layer stacked in sequence. The evaporation coating device includes a cavity, an evaporation system, a carrying system, and a monitoring system located within the cavity. The method includes: Placing the component to be coated containing the LED chip in the carrying system, and the component to be coated is located within the vapor opening of the evaporation system; For any material film layer in the electrodes of the LED chip, placing the corresponding evaporation source in the crucible within the evaporation system, and by rotating the quartz crystal wafer turntable in the monitoring system, one of the multiple quartz crystal wafers on the quartz crystal wafer turntable is located at a preset position within the vapor opening of the evaporation system, and monitoring the coating process of this material film layer. Different quartz crystal wafers correspond to different material film layers; Using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding quartz crystal wafer, and the evaporation of each material film layer in the electrodes of the LED chip is completed; For the eutectic barrier layer in the electrodes of the LED chip, the corresponding evaporation source is a Ni evaporation source, and the quartz crystal wafer located at the preset position within the vapor opening of the evaporation system on the quartz crystal wafer turntable is an aluminum-silver alloy quartz crystal wafer; Using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding quartz crystal wafer includes: Using the electron gun in the evaporation system to perform n times of electron beam bombardment on the corresponding evaporation source, and the spot scanning range of each electron beam bombardment does not overlap, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding quartz crystal wafer in n layers, where n≥2.

2. The vapor deposition method according to claim 1, characterized in that, For the ohmic contact layer in the electrodes of the LED chip, the corresponding evaporation source is a Ni evaporation source or a Cr evaporation source, and the quartz crystal wafer located at the preset position within the vapor opening of the evaporation system on the quartz crystal wafer turntable is an aluminum-silver alloy quartz crystal wafer.

3. The vapor deposition method according to claim 1, wherein During the process of the electron gun performing the n times of electron beam bombardment, the power of each electron beam bombardment is constant.

4. The evaporation deposition method according to claim 1, wherein For the eutectic soldering layer in the electrodes of the LED chip, the corresponding evaporation source is an alloy evaporation source including Sn, Ag, and Cu, and the quartz crystal wafer located at the preset position within the vapor opening of the evaporation system on the quartz crystal wafer turntable is an aluminum-silver alloy quartz crystal wafer; Using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding quartz crystal wafer includes: In the first time period, using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source at a constant plating rate, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding quartz crystal wafer; In the second time period, using the electron gun in the evaporation system to perform electron beam bombardment on the corresponding evaporation source at a constant power, so that the corresponding evaporation source is evaporated onto the component to be coated and the corresponding quartz crystal wafer.

5. The evaporation coating method according to claim 4, characterized in that The evaporation system further includes a crucible turntable for placing a plurality of the crucibles; Placing the corresponding evaporation source in the crucible within the evaporation system includes: Placing the corresponding evaporation source in multiple crucibles on the crucible turntable within the evaporation system; During the evaporation process of the eutectic welding layer, the method further includes: Using the electron gun in the evaporation system to simultaneously perform electron beam bombardment on the evaporation sources in multiple crucibles on the crucible turntable, so that the evaporation sources in multiple crucibles on the crucible turntable are simultaneously evaporated onto the component to be coated and the corresponding crystal oscillator wafers.

6. A vapor deposition apparatus, characterized in that, Applying the evaporation method according to any one of claims 1-5, the evaporation device includes a cavity and an evaporation system, a loading system, and a monitoring system located within the cavity; The evaporation system includes an electron gun and a crucible, the crucible is used to carry the evaporation source, the electron gun is used to perform electron beam bombardment on the evaporation source to vaporize the evaporation source, and the evaporation system has a steam opening; The loading system is used to load the component to be coated, and the component to be coated is located within the steam opening of the evaporation system; The monitoring system includes a crystal oscillator wafer turntable and multiple crystal oscillator wafers located on the crystal oscillator wafer turntable. The crystal oscillator wafers are located on one side of the crystal oscillator wafer turntable facing the evaporation system. When performing multi-material film evaporation on the component to be coated, for any material film layer, by rotating the crystal oscillator wafer turntable, one of the multiple crystal oscillator wafers on the crystal oscillator wafer turntable is located at a preset position within the steam opening of the evaporation system to monitor the evaporation process of this material film layer, and the crystal oscillator wafers corresponding to different material film layers are different.

7. The vapor deposition apparatus according to claim 6, wherein The multiple crystal oscillator wafers include at least one of an aluminum-silver alloy crystal oscillator wafer and a gold crystal oscillator wafer.

8. The evaporation deposition apparatus according to claim 6, characterized in that, The crucible includes an inner wall and an outer wall surrounding the inner wall. The material of the inner wall is metal, and the material of the outer wall is graphite.

9. The evaporation deposition apparatus according to claim 6, wherein The evaporation system further includes a crucible turntable for placing one or more of the crucibles.

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