Gallium removing device

Abstract

The utility model relates to a gallium removing device, which comprises a device body, a gallium removing device and a gallium removing device, the device body is provided with a cleaning cavity, a cleaning medium is accommodated in the cleaning cavity, and the cleaning medium is heated and kept at a preset temperature; wherein at the preset temperature, the metal solid gallium is converted into molten gallium; the wafer placing platform is arranged at the bottom of the cleaning cavity and is used for bearing a wafer to be cleaned; the ultrasonic transducer is arranged on one side, opposite to the wafer placing platform, of the cleaning cavity and is used for generating a cavitation effect on the surface of the wafer to be cleaned so as to decompose the molten gallium into micro-nano gallium particles; and the ultrasonic transducer is also used for inducing the cleaning medium to be decomposed so as to be subjected to oxidation reaction with the gallium particles. By applying the scheme of the invention, the residual gallium can be quickly removed, and meanwhile, the effects of environmental protection and low cost are achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor equipment, in particular to a gallium removal device. Background Art

[0002] Micro-LED (Micro Light Emitting Diode) is a new generation of display technology. Compared with LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode) technologies, it has higher brightness, better luminous efficiency, low power consumption and long life. In the process of preparing micro-light-emitting diodes, mass transfer is the key point of technological breakthrough. Its process mainly includes laser stripping, mass transfer and detection and repair process, among which laser stripping technology is the key point of mass transfer technology breakthrough. Laser stripping technology mainly utilizes the band gap difference between gallium nitride (GaN) epitaxial layer and sapphire substrate (also known as growth substrate), and uses ultraviolet laser radiation with photon energy greater than the band gap of gallium nitride and less than the band gap of sapphire to make gallium nitride thermally decompose at 900℃~1000℃ to form metal gallium and nitrogen, thereby realizing the separation of Micro-LED and sapphire substrate. The separated Micro-LED will adhere to the temporary substrate through the glue layer, and finally transfer the Micro-LED to the target substrate through the temporary substrate. However, there is often a large amount of gallium (Ga) residue on the surface of the Micro-LED adhered to the temporary substrate after laser lift-off.

[0003] As for gallium residue, the most commonly used removal methods are acid pickling and dissolving gallium in liquid above the melting point of gallium (about 30°C). However, acid pickling is corrosive to the surface of Micro-LEDs when removing residual gallium. Oxidation on the surface of gallium forms an oxide film with a melting point close to 2000°C, which cannot be dissolved by solutions above the melting point of gallium, easily resulting in oxide residue. Based on the above problems, how to more effectively remove the residual gallium on the surface of Micro-LEDs without corroding them, while also saving energy, increasing efficiency and reducing environmental pollution, has become a key link in laser lift-off technology. Utility Model Content

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a gallium removal device to solve the above-mentioned technical problems.

[0005] A gallium removal device, comprising:

[0006] The device body is provided with a cleaning chamber, in which a cleaning medium is contained, and the cleaning medium is heated and maintained at a preset temperature; wherein, at the preset temperature, metallic solid gallium is transformed into molten gallium;

[0007] A wafer placement platform, disposed at the bottom of the cleaning chamber, for carrying the wafer to be cleaned;

[0008] An ultrasonic transducer is arranged on a side of the cleaning chamber opposite to the wafer placement platform, and is used to generate a cavitation effect on the surface of the wafer to be cleaned to decompose the molten gallium into micro-nano-sized gallium particles; the ultrasonic transducer is also used to induce the decomposition of the cleaning medium and to generate an oxidation reaction with the gallium particles.

[0009] The above-mentioned gallium removal device generates a cavitation effect on the surface of the wafer to be cleaned by setting an ultrasonic transducer to decompose the molten gallium on the surface of the wafer to be cleaned into micro-nano-sized gallium particles, and further induces the decomposition of the cleaning medium to react with the gallium particles. The metal gallium remaining on the surface of the wafer to be cleaned can be oxidized to react to form oxide crystals and gradually dissolve in water, thereby achieving the purpose of removing gallium while improving the light efficiency of Micro-LEDs, and effectively avoiding the risk of acid and alkali solutions corroding the chip; in addition, the gallium removal efficiency can be significantly improved. The cavitation effect of the ultrasonic wave decomposes the molten metal gallium into micro-nano-sized metal gallium particles, greatly increasing the specific surface area of ​​the reaction and effectively increasing the reaction rate.

[0010] In one embodiment, it further includes:

[0011] The temperature detector is arranged on the side wall of the cleaning chamber and is used to detect the temperature of the cleaning medium in the cleaning chamber.

[0012] In one embodiment, it further includes:

[0013] The liquid level detector is arranged adjacent to the temperature detector and is used to detect the liquid level height of the cleaning medium in the cleaning chamber.

[0014] In one embodiment, it also includes a medium injection pipeline and a waste liquid discharge pipeline;

[0015] The medium injection pipeline and the waste liquid discharge pipeline are respectively arranged on two side walls of the cleaning chamber, and the waste liquid discharge pipeline is arranged at the junction area between the side wall and the bottom of the cleaning chamber.

[0016] In one embodiment, it further includes:

[0017] A heating device is arranged at the bottom of the cleaning chamber and adjacent to the wafer placement platform, and is used for heating the cleaning medium.

[0018] In one embodiment, it further includes:

[0019] The gas exhaust pipe is arranged adjacent to the ultrasonic transducer.

[0020] In one embodiment, the cleaning medium is water, and the preset temperature is 50°C-55°C.

[0021] In one embodiment, the wafer placement platform can rotate relative to the bottom of the cleaning chamber, and the wafer placement platform includes a base and a wafer fixing fixture, and the wafer fixing fixture is arranged on the base.

[0022] In one embodiment, the base includes a base body and a rotation driving part, a portion of the rotation driving part is accommodated in the base body, and another portion is exposed relative to the base body, and the exposed portion is rotatably connected to the wafer fixing fixture.

[0023] In one embodiment, the base includes a base body and a rotation driving part, the top end of the base body is fixedly connected to the wafer fixing fixture; the rotation driving part is accommodated in the base body and is rotationally connected to the base body. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a module of a gallium removal device in one embodiment of the present application;

[0025] Figure 2 FIG. 4 is a schematic diagram of a module of a gallium removal device in another embodiment of the present application.

[0026] Description of reference numerals:

[0027] 102-cleaning chamber; 20-ultrasonic transducer; CH-cleaning medium; 30-wafer placement platform; WF-wafer to be cleaned; 410-temperature detector; 420-liquid level detector; 510-medium injection pipeline; 520-waste liquid discharge pipeline; 60-heating device; 70-gas discharge pipeline. DETAILED DESCRIPTION

[0028] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thoroughly and comprehensively understood.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0030] As described in the background technology of this application, Micro-LED (Micro Light Emitting Diode) is a new generation of display technology. Compared with LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Diode) technology, it has higher brightness, better luminous efficiency, low power consumption and long life. In the process of preparing micro-light-emitting diodes, mass transfer is the key point of technological breakthrough. Its process mainly includes laser stripping, mass transfer and detection and repair process, among which laser stripping technology is the key point of mass transfer technology breakthrough. Laser stripping technology mainly utilizes the band gap difference between gallium nitride (GaN) epitaxial layer and sapphire substrate (also known as growth substrate), and uses ultraviolet laser radiation with photon energy greater than the band gap of gallium nitride and less than the band gap of sapphire to make gallium nitride thermally decompose at 900℃~1000℃ to form metal gallium and nitrogen, thereby realizing the separation of Micro-LED and sapphire substrate. The separated Micro-LED will adhere to the temporary substrate through the glue layer, and finally transfer the Micro-LED to the target substrate through the temporary substrate. However, there is often a large amount of gallium (Ga) residue on the surface of the Micro-LED adhered to the temporary substrate after laser lift-off.

[0031] As for gallium residue, the most commonly used removal methods are acid pickling and dissolving gallium in liquid above the melting point of gallium (about 30°C). However, acid pickling is corrosive to the surface of Micro-LEDs when removing residual gallium. Oxidation on the surface of gallium forms an oxide film with a melting point close to 2000°C, which cannot be dissolved by solutions above the melting point of gallium, easily resulting in oxide residue. Based on the above problems, how to more effectively remove the residual gallium on the surface of Micro-LEDs without corroding them, while also saving energy, increasing efficiency and reducing environmental pollution, has become a key link in laser lift-off technology.

[0032] Based on this, the present application hopes to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in the subsequent embodiments.

[0033] like Figure 1As shown, the present application provides a gallium removal device, including: a device body (not shown), an ultrasonic transducer 20, and a wafer placement platform 30. The device body is provided with a cleaning chamber 102, in which a cleaning medium CH is contained, and the cleaning medium CH is heated and maintained at a preset temperature; wherein, at the preset temperature, metal solid gallium is converted into molten gallium; in the embodiment of the present application, the cleaning medium can be water, and the preset temperature can be between 50°C and 55°C. As an example, the preset temperature can be 50°C, 51°C, 52°C, 53°C, 54°C, or 55°C; in another example, the preset temperature can be 50.5°C, 51.5°C, 52.5°C, 53.5°C, 54.5°C, or 55°C. Under this preset temperature range, it can be ensured that solid gallium is converted into molten gallium.

[0034] The wafer placement platform 30 is disposed at the bottom of the cleaning chamber 102 and is used to carry the wafer WF to be cleaned. The wafer WF to be cleaned may include a growth substrate and a plurality of Micro-LEDs formed on the growth substrate. The ultrasonic transducer 20 is disposed on the side of the cleaning chamber 102 opposite to the wafer placement platform 30 and is used to generate a cavitation effect on the surface of the wafer WF to be cleaned so as to decompose the molten gallium into micro-nano sized gallium particles. The ultrasonic transducer 20 is also used to induce the decomposition of the cleaning medium CH and to react with the gallium particles in an oxidation reaction. In the embodiment of the present application, the ultrasonic transducer 20 firstly induces the decomposition of the cleaning medium CH into a water solution into H + and OH - , followed by OH - It can react with molten gallium to generate gallium hydroxide and gradually dissolve in water, thereby achieving the purpose of removing gallium and effectively avoiding the risk of acid and alkali solutions corroding the chip. In addition, the ultrasonic transducer 20 can also produce a cavitation effect on the surface of the wafer WF to be cleaned to decompose the molten gallium into micro-nano sized gallium particles, where micro-nano size refers to particles with a size of micrometer or nanometer. Combined with the aforementioned oxidation reaction, the specific surface area of ​​the reaction can be greatly increased, effectively improving the reaction efficiency.

[0035] The above-mentioned gallium removal device generates a cavitation effect on the surface of the wafer to be cleaned by setting an ultrasonic transducer to decompose the molten gallium on the surface of the wafer to be cleaned into micro-nano-sized gallium particles, and further induces the decomposition of the cleaning medium to react with the gallium particles. The metal gallium remaining on the surface of the wafer to be cleaned can be oxidized to react to form oxide crystals and gradually dissolve in water, thereby achieving the purpose of removing gallium while improving the light efficiency of Micro-LEDs, and effectively avoiding the risk of acid and alkali solutions corroding the chip; in addition, the gallium removal efficiency can be significantly improved. The cavitation effect of the ultrasonic wave decomposes the molten metal gallium into micro-nano-sized metal gallium particles, greatly increasing the specific surface area of ​​the reaction and effectively increasing the reaction rate.

[0036] In one embodiment, see Figure 2 , the gallium removal device of the present application may also include:

[0037] The temperature detector 410 is disposed on the side wall of the cleaning chamber 102, and is used to detect the temperature of the cleaning medium CH in the cleaning chamber 102. It can be determined that, when working, the temperature detector 410 should be below the liquid surface of the cleaning medium CH, and at the same time, the wafer placement platform 30 should also be below the liquid surface of the cleaning medium CH. In other words, the cleaning medium CH covers the temperature detector 410 and the wafer placement platform 30. In this specific embodiment, the maximum temperature detection value of the temperature detector 410 can be 55°C, and the minimum temperature detection value can be 50°C.

[0038] In one embodiment, see Figure 2 , the gallium removal device of the present application may also include:

[0039] The liquid level detector 420 is disposed adjacent to the temperature detector 410 and is used to detect the liquid level of the cleaning medium in the cleaning chamber 102. In the embodiment of the present application, the liquid level detector 420 may be disposed slightly higher than the temperature detector 410 or may be on the same horizontal line as the temperature detector 410.

[0040] In one embodiment, see Figure 2, the gallium removal device of the present application may also include a medium injection pipe 510 and a waste liquid discharge pipe 520; the medium injection pipe 510 and the waste liquid discharge pipe 520 are respectively arranged on the two side walls of the cleaning chamber 102, and the waste liquid discharge pipe 520 is arranged at the junction area between the side wall and the bottom of the cleaning chamber 102. The medium injection pipe 510 cooperates with the liquid level detector 420 to realize the liquid level control of the cleaning medium CH, and the waste liquid discharge pipe 520 can be actuated when the liquid level is too high or the reaction is completed to control the discharge of the waste liquid. In the embodiment of the present application, the waste liquid discharge pipe 520 and the temperature detector 410 are arranged on the same side, and the medium injection pipe 510 is arranged on the opposite side and can be located in the middle position or the middle upper position of the side wall of the cleaning chamber 102. It should be determined that the height of the medium injection pipe 510 needs to be higher than the height of the cleaning medium CH to avoid pipeline contamination and medium backflow.

[0041] In one embodiment, see Figure 2 , the gallium removal device of the present application may also include: a heating device 60, which is arranged at the bottom of the cleaning chamber 102 and is arranged adjacent to the wafer placement platform 30, for heating the cleaning medium CH. In the embodiment of the present application, the heating device 60 can be actuated in conjunction with the temperature detector 410 in the aforementioned embodiment. For example, when the temperature detector 410 detects that the current temperature of the cleaning medium CH is lower than 50°C, the heating device 60 is enabled to start heating the cleaning medium CH; when the temperature detector 410 detects that the current temperature of the cleaning medium CH is higher than 55°C, it is necessary to control the heating device 60 to be turned off to stop heating the cleaning medium CH.

[0042] In one embodiment, see Figure 2 The gallium removal device of the present application may further include a gas exhaust pipeline 70, which is disposed adjacent to the ultrasonic transducer 20. In this specific embodiment, the provision of the gas exhaust pipeline 70 is helpful for exhausting waste gas.

[0043] In one embodiment, the wafer placement platform 30 can rotate relative to the bottom of the cleaning chamber 102. The wafer placement platform 30 includes a base (not shown) and a wafer fixing fixture (not shown). The wafer fixing fixture is disposed on the base.

[0044] Furthermore, the base may include a base body (not shown) and a rotation drive unit (not shown), a portion of the rotation drive unit is accommodated in the base body, and another portion is exposed relative to the base body, and the exposed portion is rotatably connected to the wafer fixing fixture. That is to say, in this specific embodiment, a portion of the wafer placement platform 30 (wafer fixing fixture) is a rotatable component, and by controlling the wafer fixing fixture to drive the wafer to be cleaned to rotate, full coverage of the cleaning area can be achieved.

[0045] In another embodiment, the base includes a base body and a rotation drive unit, the top of the base body is fixedly connected to the wafer fixing fixture; the rotation drive unit is accommodated in the base body and is rotationally connected to the base body. That is to say, in this specific embodiment, the entire wafer placement platform 30 is rotatable, and by controlling the rotation drive unit to drive the wafer to be cleaned to rotate, full coverage of the cleaning area can be achieved.

[0046] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made according to the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A gallium removal device, characterized in that: include: The device body is provided with a cleaning chamber, in which a cleaning medium is contained, and the cleaning medium is heated and maintained at a preset temperature; wherein, at the preset temperature, metallic solid gallium is transformed into molten gallium; A wafer placement platform, disposed at the bottom of the cleaning chamber, for carrying the wafer to be cleaned; An ultrasonic transducer is arranged on a side of the cleaning chamber opposite to the wafer placement platform, and is used to generate a cavitation effect on the surface of the wafer to be cleaned to decompose the molten gallium into micro-nano-sized gallium particles; the ultrasonic transducer is also used to induce the decomposition of the cleaning medium and to generate an oxidation reaction with the gallium particles.

2. The gallium removal device according to claim 1, characterized in that: Also includes: The temperature detector is arranged on the side wall of the cleaning chamber and is used to detect the temperature of the cleaning medium in the cleaning chamber.

3. The gallium removal device according to claim 2, characterized in that: Also includes: The liquid level detector is arranged adjacent to the temperature detector and is used to detect the liquid level height of the cleaning medium in the cleaning chamber.

4. The gallium removal device according to claim 1, characterized in that: It also includes a medium injection pipeline and a waste liquid discharge pipeline; The medium injection pipeline and the waste liquid discharge pipeline are respectively arranged on two side walls of the cleaning chamber, and the waste liquid discharge pipeline is arranged at the junction area between the side wall and the bottom of the cleaning chamber.

5. The gallium removal device according to claim 1, characterized in that: Also includes: A heating device is arranged at the bottom of the cleaning chamber and adjacent to the wafer placement platform, and is used for heating the cleaning medium.

6. The gallium removal device according to claim 1, characterized in that: Also includes: The gas exhaust pipe is arranged adjacent to the ultrasonic transducer.

7. The gallium removal device according to any one of claims 1 to 6, characterized in that: The cleaning medium is water, and the preset temperature is 50°C-55°C.

8. The gallium removal device according to any one of claims 1 to 6, characterized in that: The wafer placement platform can rotate relative to the bottom of the cleaning chamber. The wafer placement platform includes a base and a wafer fixing fixture. The wafer fixing fixture is arranged on the base.

9. The gallium removal device according to claim 8, characterized in that: The base comprises a base body and a rotation driving part, a part of the rotation driving part is accommodated in the base body, and another part is exposed relative to the base body, and the exposed part is rotationally connected to the wafer fixing fixture.

10. The gallium removal device according to claim 8, characterized in that: The base comprises a base body and a rotation driving part. The top of the base body is fixedly connected to the wafer fixing fixture. The rotation driving part is accommodated in the base body and is rotationally connected to the base body.

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