An automatic leveling device for MicroLED mass transfer and its application

Abstract

The present invention belongs to the technical field related to semiconductors, and discloses a self-leveling device for MicroLED mass transfer and its application. The device includes: a lower wafer moving stage, which includes a first bracket with degrees of freedom in three directions of X, Y, and Z and a slide table; an upper wafer moving stage, which includes a second bracket with degrees of freedom in three directions of X, Y, and Z and an adsorption structure; a substrate direct-drive self-leveling micro gimbal, which includes a spherical motor and a self-leveling micro gimbal. The spherical motor is arranged on the slide table, and the self-leveling micro gimbal realizes rotation or locking in the X, Y, or Z direction under the drive of the spherical motor; the self-leveling micro gimbal includes a synchronous adjustment disk and a lower wafer adsorption disk. A plurality of ejector pins are arranged on the surface of the synchronous adjustment disk, and force sensors are respectively arranged above the ejector pins. The lower wafer adsorption disk is provided with holes corresponding to the ejector pins so that the force sensors protrude from the surface of the lower wafer adsorption disk. This application is not limited by the area of the transfer head, can achieve parallelism during large-plane transfer, and significantly improves the transfer efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field related to semiconductors, and more specifically, relates to a self-leveling device for MicroLED mass transfer and its application. Background Art

[0002] Micro Light Emitting Diode (MicroLED, also known as μLED) is a new generation of inorganic self-luminous display technology that miniaturizes the size of traditional LEDs to less than 50 μm and highly integrates the driving circuit on a single chip. Compared with traditional display technologies, it has unique advantages such as higher brightness, lower power consumption, longer lifespan, faster response, and higher reliability, and has wide applications in high-resolution displays, biomedicine, visible light communication, wearable electronics, and other fields. One of the development difficulties of current μLED technology lies in the mass transfer process, which requires transferring millions of micron-sized μLEDs from the epitaxial growth substrate to the circuit board. However, the current mass transfer processes and devices cannot meet the requirements of high yield (~99.9999%), high precision (±0.5 μm), and high speed (1M / h).

[0003] In response to the above problems, Chinese Patent CN109712928B discloses a high-precision transfer device and system suitable for micro-devices, which can achieve the adsorption and release of micro-devices through the electrostatic adsorption force generated by an electrostatic chuck. Using electrostatic force as the energy source for transfer makes the power consumption of the transfer device lower, and it can adapt to the transfer of different forms of devices. At the same time, the transfer head can move in the horizontal and vertical planes under the control of a mobile device to transfer different specifications of transfer substrates, improving the transfer efficiency and reducing the production cost. Chinese Patent CN109216400B discloses a mass transfer device and related method for MicroLED array devices. By forming a magnetic nanometer thin film layer on the epitaxial substrate of the MicroLED array device as an electrode of the MicroLED array device, the MicroLED array device can be directly adsorbed by magnetic force. This method does not require additional setting of a magnetic layer, avoiding the processes of manufacturing and removing the magnetic layer, simplifying the transfer method of the MicroLED array device, and improving the mass transfer efficiency.

[0004] The above two methods overcome the deficiencies of the traditional mechanical method, which is difficult to pick up and easily damages the chip. However, due to the size of the transfer head, the transfer efficiency is restricted to a certain extent. At the same time, the force regulation needs to be achieved within a specific range, resulting in a reduced process window and increased industrial costs. Chinese Patent CN111584689A discloses a MicroLED mass transfer device and its transfer method, which uses mask illumination and conveyor belt transfer to achieve the irradiation transfer of multi-array MicroLEDs. During the transfer, the MicroLEDs located on the sapphire substrate are irradiated and transferred to the adhesive layer of the conveyor belt by laser. This method generates the force for transferring the chips through light irradiation, and then uses methods such as masks and spot focusing array to achieve selectivity and the way of arrayed light spots, improving the efficiency of the mass transfer device and method.

[0005] Laser transfer technology is based on the interaction mechanism between laser and matter. It uses the absorption of beam energy by materials in the interface region to cause rapid physical changes or chemical reactions to generate a driving force to regulate the interface state, so as to overcome the adhesion force between the surface material and the MicroLED. It has advantages such as small damage to the device, high selectivity, rapid and efficient response, etc. Moreover, compared with other technologies, laser has advantages in repair. It can melt the defective points, which plays a great role in improving the yield. Under appropriate process parameters, it can achieve a high yield, precision and transfer rate, and has now become a very potential mass transfer solution. However, although laser transfer can meet the requirements of high-speed and selective transfer, there are many factors affecting the transfer precision. It is necessary to study various parameters such as laser parameters (such as laser energy density, pulse frequency, spot size, etc.) and geometric parameters of the transfer device (such as plate spacing, chip spacing, etc.). In addition, laser equipment is expensive, and the cost is relatively high. Especially during the transfer process, the donor substrate and the receiving substrate need to move in coordination with the laser spot, and the spacing and relative parallelism between the two directly affect the yield and precision of the mass transfer, which is the technical core and difficulty in the development of the mass transfer device suitable for the current process. Summary of the Invention

[0006] In view of the above defects or improvement requirements of the prior art, the present invention provides a self-leveling device for MicroLED mass transfer and its application. This application is not limited by the area of the transfer head, and can achieve large-plane transfer within the allowable parallelism range of errors, significantly improving the transfer efficiency, and solving the problem of transfer deviation caused by the substrate spacing in the non-contact laser mass transfer of MicroLEDs.

[0007] To achieve the above object, according to one aspect of the present invention, a self-leveling device for MicroLED mass transfer is provided. The device includes: a lower wafer moving stage, which includes a first bracket having degrees of freedom in three directions of X, Y, and Z, and a sliding table provided on the first bracket, so that the sliding table moves along the X, Y, or Z direction on the first bracket; an upper wafer moving stage, which includes a second bracket having degrees of freedom in three directions of X, Y, and Z, and an adsorption structure provided on the second bracket, and the adsorption structure is located above the sliding table; the adsorption structure includes an upper wafer adsorption disk, and the upper wafer adsorption disk is used for adsorbing the upper wafer; a substrate direct-drive self-leveling micro gimbal includes a spherical motor and a self-leveling micro gimbal. The spherical motor is provided on the sliding table, and the self-leveling micro gimbal rotates or locks in the X, Y, or Z direction under the drive of the spherical motor; the self-leveling micro gimbal includes a synchronous adjustment disk and a lower wafer adsorption disk provided above the synchronous adjustment disk. A plurality of top columns are provided on the surface of the synchronous adjustment disk, and force sensors are respectively provided above the top columns. The lower wafer adsorption disk is provided with holes corresponding to the top columns so that the force sensors protrude from the surface of the lower wafer adsorption disk.

[0008] Preferably, the self-leveling micro gimbal further includes guide posts and height-adjusting nuts. The guide posts are fixed to the lower surface of the lower wafer adsorption disk, and the synchronous adjustment disk is provided with holes corresponding to the guide posts to prevent the misalignment of the positions of the lower wafer adsorption disk and the synchronous adjustment disk. The height-adjusting nuts are used to adjust the height of the top columns, thereby controlling the distance between the upper and lower wafers.

[0009] Preferably, the spherical motor includes a spherical stator, a ball joint, a spherical housing, a plurality of permanent magnets, a wire winding wound on the surface of the permanent magnets, and an internal sensor. Among them, the ball joint is provided outside the spherical stator. The ball joint includes a spherical part, a top cover rotating shaft provided on the surface of the spherical part, and a top cover provided above the top cover rotating shaft. The self-leveling micro gimbal is provided on the top cover; the plurality of permanent magnets are evenly distributed in and penetrate through the spherical housing, and the internal sensor is used to feedback and control the performance of the spherical motor.

[0010] Preferably, the second bracket includes a cap-shaped bracket. The adsorption structure further includes a vacuum chuck adapter and a rotary displacement stage sleeved on one end of the vacuum chuck adapter. A plurality of fine-tuning screws are provided on the rotary displacement stage, and the upper wafer adsorption disk is provided at the end of the vacuum chuck adapter. The plurality of fine-tuning screws are used to adjust the parallelism of the upper wafer adsorption disk.

[0011] Preferably, the first bracket includes a first X-direction motion guide rail, a first Y-direction motion guide rail, and a first Z-direction motion guide rail. The first X-direction motion guide rail and the first Y-direction motion guide rail are provided below the first Z-direction motion guide rail, and the sliding table is provided on the first Z-direction motion guide rail.

[0012] Preferably, the second bracket is of a gantry structure. The second bracket includes a second X-direction movement guide rail, a second Y-direction movement guide rail, and a second Z-direction movement guide rail. The adsorption structure is arranged on the second Z-direction movement guide rail.

[0013] Preferably, the device further includes a control system for controlling the operation of the lower wafer moving stage, the upper wafer moving stage, and the substrate direct drive self-leveling micro gimbal.

[0014] Preferably, the device further includes a fixed support base for supporting the lower wafer moving stage, the upper wafer moving stage, and the substrate direct drive self-leveling micro gimbal.

[0015] According to another aspect of the present invention, there is provided an application of a self-leveling device for MicroLED mass transfer, and the device is applied to laser transfer of MicroLED.

[0016] Generally speaking, compared with the prior art by the above technical solutions conceived by the present invention, the present invention provides a self-leveling device for MicroLED mass transfer and its application:

[0017] 1. In the present application, the parallelism of the adsorbed upper wafer and lower wafer can be self-adjusted through the spherical motor and the self-leveling micro gimbal, and thus the transfer accuracy during the non-contact transfer process can be ensured. Even if the areas of the upper wafer adsorption disc and the lower wafer adsorption disc are very large, good parallelism can be maintained. Therefore, more MicroLEDs can be transferred at one time, and thus the transfer efficiency is significantly improved.

[0018] 2. The error caused by the roughness of the upper wafer adsorption disc and the lower wafer adsorption disc can be overcome through the top column and the force sensor arranged on the top column, and the transfer accuracy is ensured. The posture of the lower wafer adsorption disc can be fixed through the spherical motor, and thus the frequent adjustment during different batch transfers is avoided, and the transfer efficiency is significantly improved.

[0019] 3. The movement of the self-leveling micro gimbal is controlled by the on / off of the permanent magnet, and the response is timely.

[0020] 4. The device in the present application is very suitable for laser transfer of MicroLED, can realize the high-precision relative movement or overall movement of the donor / receiving substrate, realizes the mass transfer of micro-devices, effectively improves the production efficiency, and promotes the commercial process. Description of the Drawings

[0021] Figure 1 It is the overall structure diagram of the self-leveling device for MicroLED mass transfer;

[0022] Figure 2It is the structural diagram of the lower wafer moving stage of the self-leveling device for MicroLED mass transfer;

[0023] Figure 3 It is the structural diagram of the upper wafer moving stage of the self-leveling device for MicroLED mass transfer;

[0024] Figure 4 It is the structural diagram of the substrate direct drive self-leveling micro gimbal and the lower wafer moving stage;

[0025] Figure 5A It is the overall structural diagram of the spherical motor;

[0026] Figure 5B It is the sectional view of the spherical motor;

[0027] Figure 6 It is the control schematic diagram of the control system.

[0028] In all the drawings, the same reference numerals are used to denote the same elements or structures, where:

[0029] 100 - Fixed support base, 101 - Marble base, 102 - Rubber pad, 103 - Drawer slide rail, 104 - Slide rail bracket, 105 - Structural steel bracket, 106 - Caster, 107 - Adjustable foot pad, 108 - Locker;

[0030] 200 - Lower wafer moving stage, 201 - Interference anti-collision device, 202 - Slide table, 203 - First Z-direction movement guide rail, 204 - Drag chain, 205 - Encapsulation cover, 206 - Fixing part, 207 - First X-direction movement guide rail, 208 - Linear motor, 209 - Anti-collision limit, 210 - Anti-collision limit, 211 - Servo motor, 212 - Screw-nut mechanism;

[0031] 300 - Upper wafer moving stage, 301 - Gantry marble, 302 - Y-axis drag chain baffle, 303 - Y-axis drag chain, 304 - Encapsulation cover, 305 - Fixing part, 306 - Anti-collision limit, 307 - Vacuum chuck adapter, 308 - Upper wafer suction chuck, 309 - Rotary displacement stage, 310 - Fine adjustment set screw, 311 - Second X-direction movement guide rail, 312 - Hat-shaped bracket, 313 - Anti-collision limit, 314 - Servo motor, 315 - Z-axis drag chain, 316 - Interference anti-collision device;

[0032] 400 - Substrate direct drive self-leveling micro gimbal, 401 - Spherical motor, 402 - Heightening nut, 403 - Top column, 404 - Synchronous adjustment disc, 405 - Guide post, 406 - Lower wafer suction chuck;

[0033] 501 - Top cover, 502 - Spherical shell, 503 - Permanent magnet, 504 - Spherical motor base, 505 - Spherical stator, 506 - Wire winding, 507 - Ball joint, 508 - Top cover rotating shaft. Detailed implementation manners

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Please refer to Figure 1 and Figure 2 , the present invention provides a self - leveling device for MicroLED mass transfer, including a lower wafer moving stage 200, an upper wafer moving stage 300, a substrate direct - drive self - leveling micro - cloud platform 400, a fixed support base 100, and a control system (as Figure 6 shown). The lower wafer moving stage 200 and the upper wafer moving stage 300 are fixed on the fixed support base 100. The lower wafer moving stage 200 is used for fixing and moving the lower wafer (i.e., the receiving substrate). The upper wafer moving stage 300 is used for fixing and moving the upper wafer (i.e., the donor substrate). The lower wafer moving stage 200, the upper wafer moving stage 300, and the substrate direct - drive self - leveling micro - cloud platform 400 realize the functions of wafer loading and movement through the control system. The lower wafer moving stage 200 and the upper wafer moving stage 300 can keep the two wafers relatively stationary at the concentric position and perform overall translation under the action of the control system, so as to meet the movement requirements of the laser process. Their movement accuracy is determined by the manufacturing accuracy of the movement components and the control accuracy of the control components;

[0036] As Figure 1 shown, the fixed support base 100 includes a marble base 101, a rubber pad 102, a drawer slide rail 103, a slide rail bracket 104, a structural steel bracket 105, casters 106, adjustable feet 107, and a storage cabinet 108. The adjustable feet 107 and the casters 106 are installed at the four bottom corners under the structural steel bracket 105 to play the role of fixed support and handling of the entire movement platform; the lengths of the four adjustable feet 107 are changed through threads to finely adjust the level of the upper plane of the marble base 101; the marble base 101 is placed on the rubber pad 102 of the structural steel bracket 105 to provide a reference for the movement directions of the movement platform; the slide rail bracket 104 is installed on the structural steel bracket 105 and fixedly installs the drawer slide rail 103. The storage cabinet 108 is fixed on the drawer slide rail 103 and placed in the vacant space of the structural steel bracket 105 for equipment storage.

[0037] AsFigure 2 As shown, the lower wafer stage 200 is installed on the marble base 101 and fixed by the fixing member 206. The lower wafer stage 200 includes a first bracket having degrees of freedom in three directions of X, Y, and Z, and a slide table 202 provided on the first bracket, so that the slide table 202 moves in the first bracket along the X, Y, or Z direction.

[0038] Further, in this embodiment, the first bracket includes a first X-direction movement guide rail 207, a first Y-direction movement guide rail, and a first Z-direction movement guide rail 203. The first X-direction movement guide rail and the first Y-direction movement guide rail are provided below the first Z-direction movement guide rail 203, and the slide table is provided on the first Z-direction movement guide rail. The first Z-direction movement guide rail 203 can be a screw-nut mechanism 212. Anti-collision limiters 209 are provided at the ends of the first X-direction movement guide rail 207 and the first Y-direction movement guide rail. An anti-collision limiter 210 is provided at the end of the first Z-direction movement guide rail 203. The lower wafer stage 200 further includes a linear motor 208, a servo motor 211, an interference anti-collision device 201, a drag chain 204, a packaging cover 205, etc. The movement structure components of the lower wafer stage 200 provide high-precision translational degrees of freedom for the lower wafer in three directions of X, Y, and Z.

[0039] As Figure 3 shown, the upper wafer stage 300 is preferably a gantry structure. The second bracket includes a second X-direction movement guide rail 311, a second Y-direction movement guide rail, and a second Z-direction movement guide rail. The adsorption structure is provided on the second Z-direction movement guide rail. Anti-collision limiters 306 are provided at the ends of the second X-direction movement guide rail 311 and the second Y-direction movement guide rail. An anti-collision limiter 313 is provided at the end of the second Z-direction movement guide rail. The second bracket further includes a gantry marble 301 and its fixing member 305, a Y-axis drag chain baffle 302, a Y-axis drag chain 303, 315 is a Z-axis drag chain, a cap-shaped bracket 312, a servo motor 314, a fine adjustment jackscrew 310, an interference anti-collision device 316, a packaging cover 304, etc., providing high-precision translational degrees of freedom in three directions of X, Y, and Z and a manual rotational degree of freedom in the horizontal direction; the adsorption structure further includes a vacuum chuck adapter 307 and a rotary displacement table sleeved on one end of the vacuum chuck adapter 307. A plurality of fine adjustment jackscrews 310 are provided on the rotary displacement table 309. The upper wafer suction chuck 308 is provided at the end of the vacuum chuck adapter 307. The plurality of fine adjustment jackscrews 310 are used to adjust the parallelism of the upper wafer suction chuck 308.

[0040] As Figure 4As shown, the substrate direct drive self-leveling micro gimbal 400 is installed on the lower wafer moving stage 200, and includes a spherical motor 401 and a self-leveling micro gimbal. The spherical motor 401 is arranged on the slide table, and the self-leveling micro gimbal realizes rotation or locking in the X, Y or Z directions under the drive of the spherical motor. The self-leveling micro gimbal includes a synchronous adjustment disk 404 and a lower wafer suction disk 406 arranged above the synchronous adjustment disk 404. A plurality of ejector pins 403 are arranged on the surface of the synchronous adjustment disk 404, and force sensors are respectively arranged above the ejector pins 403. The lower wafer suction disk 406 is provided with holes corresponding to the ejector pins 403 so that the force sensors protrude from the surface of the lower wafer suction disk 406.

[0041] The self-leveling micro gimbal further includes guide posts 405 and height adjustment nuts 402. The guide posts 405 are fixed to the lower surface of the lower wafer suction disk 406, and the synchronous adjustment disk 404 is provided with holes corresponding to the guide posts 405 to prevent the position dislocation between the lower wafer suction disk 406 and the synchronous adjustment disk 404. The height adjustment nuts 402 are used to adjust the height of the ejector pins 403, thereby controlling the distance between the upper and lower wafers. The number of the ejector pins 403 is preferably 3, and the 3 ejector pins 403 are evenly distributed on the outer periphery of the synchronous adjustment disk 404.

[0042] The self-leveling micro gimbal can provide three rotational degrees of freedom for the lower wafer around the X, Y, and Z directions under the drive of the spherical motor. After the upper wafer and the lower wafer are concentrically aligned, the upper wafer is slowly moved to contact the ejector pins 403. At this time, the spherical motor adaptively adjusts the pose of the lower wafer by rotating in different directions until the upper wafer is in full contact with the three ejector pins 403, and it is considered that the two wafers are parallel, and the self-leveling process is completed at this time. In this application, both the upper wafer suction disk and the lower wafer suction disk adopt a detachable connection method to facilitate the replacement of the upper wafer suction disk and the lower wafer suction disk of different sizes according to different needs.

[0043] As Figure 5A and 5BAs shown in the figure, the spherical motor 401 includes a spherical stator 505, a ball joint 507, a spherical housing 502, a plurality of permanent magnets 503, a wire winding 506 wound around the surface of the permanent magnets, and built-in sensors. Among them, the ball joint 507 is arranged outside the spherical stator 505. The ball joint 507 includes a ball part, a top cover rotating shaft 508 arranged on the surface of the ball part, and a top cover 501 arranged above the top cover rotating shaft 508. The self-leveling micro gimbal is arranged on the top cover; the plurality of permanent magnets 503 are evenly distributed in and penetrate through the spherical housing 502. The spherical motor is connected to the sliding table 202 through a spherical motor base 504. After the wire winding 506 is energized, the ball joint 507 can rotate in three directions of X, Y, or Z around the spherical stator 505 under the action of the armature; the built-in sensors are used for feedback and motor control. For example, they can be motor parameter sensors such as a rotating shaft inertia sensor, a rotational speed sensor, a position sensor, and a temperature sensor, which are respectively used to monitor performance parameters such as the rotational speed, temperature, and rotating shaft angle of the motor.

[0044] During the working process, the operation steps of the self-leveling device for MicroLED mass transfer are as follows:

[0045] Step 1: Adsorb the upper wafer on the upper wafer adsorption plate 308, and adsorb the lower wafer on the lower wafer adsorption plate 406;

[0046] Step 2: Control the upper wafer moving stage 300 and the lower wafer moving stage 200 to move in the XY direction so that the two adsorption plates are concentrically aligned;

[0047] Step 3: Obtain the processing errors of the upper wafer adsorption plate 308 and the lower wafer adsorption plate 406, obtain the parallelism balance spacing, rotate the height-adjusting nut 402, and synchronously adjust the heights of the plurality of ejector pins 403 until the spacing at each ejector pin cancels out the processing error, that is, leveling is achieved;

[0048] Step 4: Obtain the indication values of the force sensors at the ends of the plurality of ejector pins during leveling, and keeping this indication value unchanged each time when transferring MicroLEDs can ensure the parallelism during each transfer.

[0049] In summary, the present application is not limited by the area of the transfer head, can achieve parallelism during the large-plane transfer process, significantly improve the transfer efficiency, and solve the problem of transfer deviation caused by the substrate spacing during MicroLED mass transfer.

[0050] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-leveling device for MicroLED mass transfer, characterized in that, The device includes: A lower wafer moving stage, including a first bracket with degrees of freedom in three directions of X, Y, and Z, and a slide table provided on the first bracket, so that the slide table moves along the X, Y, or Z direction on the first bracket; An upper wafer moving stage, including a second bracket with degrees of freedom in three directions of X, Y, and Z, and an adsorption structure provided on the second bracket, the adsorption structure being located above the slide table; the adsorption structure includes an upper wafer adsorption disc for adsorbing the upper wafer; The substrate direct drive self-leveling micro gimbal includes a spherical motor and a self-leveling micro gimbal. The spherical motor is provided on the slide table, and the self-leveling micro gimbal realizes rotation or locking in the X, Y, or Z direction under the drive of the spherical motor; the self-leveling micro gimbal includes a synchronous adjustment disc and a lower wafer adsorption disc provided above the synchronous adjustment disc. A plurality of top columns are provided on the surface of the synchronous adjustment disc, and force sensors are respectively provided above the top columns. The lower wafer adsorption disc is provided with holes corresponding to the top columns so that the force sensors protrude from the surface of the lower wafer adsorption disc; The spherical motor includes a spherical stator, a ball joint, a spherical housing, a plurality of permanent magnets, a wire winding wound on the surface of the permanent magnets, and an internal sensor. Among them, the ball joint is provided outside the spherical stator. The ball joint includes a spherical part, a top cover rotating shaft provided on the surface of the spherical part, and a top cover provided above the top cover rotating shaft. The self-leveling micro gimbal is provided on the top cover; the plurality of permanent magnets are evenly distributed in and penetrate through the spherical housing; the internal sensor is used to feedback and control the performance of the spherical motor.

2. The device according to claim 1, characterized in that, The self-leveling micro gimbal further includes guide posts and height-adjusting nuts. The guide posts are fixed to the lower surface of the lower wafer adsorption disc, and the synchronous adjustment disc is provided with holes corresponding to the guide posts to prevent the dislocation of the positions of the lower wafer adsorption disc and the synchronous adjustment disc. The height-adjusting nuts are used to adjust the height of the top columns, thereby controlling the distance between the upper and lower wafers.

3. The device according to claim 1, wherein The second bracket includes a cap-shaped bracket. The adsorption structure further includes a vacuum chuck adapter and a rotary displacement table sleeved at one end of the vacuum chuck adapter. A plurality of fine adjustment set screws are provided on the rotary displacement table, and the upper wafer adsorption disc is provided at the end of the vacuum chuck adapter. The plurality of fine adjustment set screws are used to adjust the parallelism of the upper wafer adsorption disc.

4. The device according to claim 1, characterized in that, The first bracket includes a first X-direction motion guide rail, a first Y-direction motion guide rail, and a first Z-direction motion guide rail. The first X-direction motion guide rail and the first Y-direction motion guide rail are provided below the first Z-direction motion guide rail, and the slide table is provided on the first Z-direction motion guide rail.

5. The device according to claim 1 or 4, characterized in that, The second bracket is of a gantry structure. The second bracket includes a second X-direction motion guide rail, a second Y-direction motion guide rail, and a second Z-direction motion guide rail. The adsorption structure is provided on the second Z-direction motion guide rail.

6. The device according to claim 1, characterized in that, The device further includes a control system for controlling the operation of the lower wafer moving stage, the upper wafer moving stage, and the substrate direct drive self-leveling micro gimbal.

7. The device according to claim 1, characterized in that, The device further includes a fixed support base for supporting the lower wafer moving stage, the upper wafer moving stage, and the substrate direct drive self-leveling micro gimbal.

8. An application of the self-leveling device for MicroLED mass transfer according to any one of claims 1 to 7, characterized in that, The device is applied to laser transfer of MicroLEDs.

Images