Seal and preparation method thereof, transfer equipment and mass transfer method

Abstract

The seal comprises a base plate and a plurality of limiting structures which are located on one side of the base plate and distributed at intervals. The multiple transfer structures are located on one side, where the limiting structures are located, of the substrate and are distributed at intervals; the multiple limiting structures correspond to the multiple transfer structures one to one, the limiting structures surround the peripheries of the transfer structures, orthographic projections of the limiting structures and the transfer structures on the substrate are not overlapped, and the distance between the end face of the end, away from the substrate, of each transfer structure and the substrate is larger than the distance between the end face of the end, away from the substrate, of each limiting structure and the substrate.

Description

Seal and its preparation method, transfer equipment and mass transfer method Technical Field

[0001] The embodiments of the present disclosure belong to the field of display technology, and specifically relate to a seal and a preparation method thereof, a transfer device, and a mass transfer method. Background Art

[0002] Micro LED (Micro Light-Emitting Diode) has the characteristics of self-luminescence without the need for a backlight. Compared with LCD (Liquid Crystal Display) and OLED (Organic Light Emitting Display) products, it has the advantages of simple structure, very long service life, high brightness, low power consumption, ultra-high resolution, etc., and has good application prospects.

[0003] Summary of the Invention

[0004] In a first aspect, an embodiment of the present disclosure provides a seal, which includes a substrate,

[0005] A plurality of limiting structures are located on one side of the substrate and are spaced apart;

[0006] A plurality of transfer structures are located on a side of the substrate where the limiting structure is located and are distributed at intervals;

[0007] The plurality of limiting structures correspond one to one with the plurality of transfer structures.

[0008] The limiting structure surrounds the periphery of the transfer structure, and the orthographic projections of the limiting structure and the transfer structure on the substrate do not overlap.

[0009] The distance between the end surface of the transfer structure away from the substrate and the substrate is greater than the distance between the end surface of the limiting structure away from the substrate and the substrate.

[0010] In some embodiments, the transfer structure includes a protrusion and an adjustable viscosity layer, wherein the protrusion and the adjustable viscosity layer are sequentially stacked away from the substrate.

[0011] The adjustable viscosity layer coincides with an orthographic projection of the protrusion on the substrate.

[0012] The present disclosure also provides a seal, which includes a substrate,

[0013] A plurality of limiting structures are located on one side of the substrate and are spaced apart;

[0014] a plurality of raised portions, located on a side of the substrate where the limiting structure is located, and distributed at intervals;

[0015] The plurality of limiting structures correspond to the plurality of protrusions one by one,

[0016] The limiting structure surrounds the periphery of the protrusion, and the limiting structure and the orthographic projection of the protrusion on the substrate do not overlap.

[0017] The distance between the end surface of the protrusion away from the substrate and the substrate is greater than the distance between the end surface of the limiting structure away from the substrate and the substrate;

[0018] The viscosity-adjustable layer is located on a side of the limiting structure and the protrusion facing away from the substrate, and the orthographic projection of the viscosity-adjustable layer on the substrate at least covers the protrusion.

[0019] In some embodiments, the orthographic projection shape of the limiting structure on the substrate is annular.

[0020] The protrusion is butted against the orthographic projection pattern of the limiting structure on the substrate.

[0021] In some embodiments, 1 / 3 of the height of the protrusion ≤ the height of the limiting structure ≤ 3 / 4 of the height of the protrusion.

[0022] In some embodiments, the height of the protrusions ranges from 5 to 20 μm.

[0023] In some embodiments, the width of the annular surface of the limiting structure ranges from 2 to 30 μm.

[0024] In some embodiments, the thickness of the adjustable viscosity layer is in the range of 1 to 5 μm.

[0025] In some embodiments, the viscosity-adjustable layer includes a viscosity sublayer and an ion-degrading layer, and the ion-degrading layer and the viscosity sublayer are sequentially stacked away from the substrate;

[0026] The thickness of the adhesive sublayer ranges from 1 to 5 μm;

[0027] The thickness of the deionizing layer ranges from 0.1 to 2 μm.

[0028] In some embodiments, the orthographic projection shape of the protrusion on the substrate includes a circle, a rectangle, a triangle, or a polygon.

[0029] In some embodiments, the plurality of protrusions are arranged in an array at equal intervals;

[0030] The orthographic projections of the plurality of protrusions on the substrate have the same shape, and the directions of the orthographic projections of any two adjacent rows of protrusions on the substrate are different;

[0031] Alternatively, the orthographic projection shapes of some of the plurality of protrusions on the substrate are different from the orthographic projection shapes of another portion on the substrate.

[0032] In some embodiments, a portion of the plurality of protrusions are arranged in an array at a first interval, and another portion are arranged in an array at a second interval, wherein the first interval is greater than the second interval.

[0033] In some embodiments, the material of the protrusion includes any one of acrylic resin, propylene glycol methyl ether acetate, silicone resin and acrylic resin.

[0034] In some embodiments, the material of the limiting structure includes any one of silicon oxide, silicon nitride, silicon oxynitride, copper, aluminum, molybdenum and silver.

[0035] In some embodiments, the material of the viscosity-adjustable layer includes any one of UV viscosity-reducing glue, thermal foaming viscosity-reducing glue, and laser dissociation glue;

[0036] The main material of the UV viscosity-reducing glue includes any one of epoxy acrylate, polyurethane acrylate, polyether acrylate, polyester acrylate, and acrylic resin;

[0037] The main material of the hot foaming viscosity-reducing glue includes one or more of styrene-butadiene rubber, polyisoprene rubber, polyisobutylene and butyl rubber, as well as synthetic rubbers such as chloroprene rubber and nitrile rubber. The main material of the hot foaming viscosity-reducing glue is mixed with foaming particles, the particle size of the foaming particles is in the range of 0.5-5 μm, and the filling rate of the foaming particles in the main material is 2% to 10%;

[0038] The main material of the laser dissociation adhesive includes one or more of acrylic resin, epoxy resin, and acrylic resin.

[0039] In some embodiments, the main material of the adhesive sublayer includes one or more of polyether resin, epoxy resin, acrylic resin, polyisoprene resin, and polyisobutylene resin;

[0040] The main material of the deionizing layer includes one or more resins such as polyimide, acrylic acid, and epoxy.

[0041] In some embodiments, a plurality of alignment marks are further included, which are located on one side of the substrate where the limiting structure is located, and are located in the peripheral area or the middle area of ​​the substrate.

[0042] The alignment mark does not overlap with the orthographic projections of the limiting structure and the protruding portion on the substrate;

[0043] The alignment mark is located on a side of the adjustable viscosity layer close to the substrate.

[0044] In a second aspect, an embodiment of the present disclosure provides a transfer device, which includes the above-mentioned seal.

[0045] In a third aspect, an embodiment of the present disclosure provides a method for preparing a seal, which includes: preparing a plurality of limiting structures on one side of a substrate using a patterning process;

[0046] A plurality of protrusions are prepared on one side of the substrate after the above steps by using a patterning process; the plurality of protrusions and the plurality of limiting structures are located on the same side of the substrate;

[0047] A viscosity-adjustable layer is prepared on the side of the substrate after completing the above steps using a patterning process; the viscosity-adjustable layer is located on the side of the limiting structure and the protrusion facing away from the substrate, and the orthographic projection of the viscosity-adjustable layer on the substrate at least covers the protrusion.

[0048] In some embodiments, the method of preparing a plurality of limiting structures on one side of the substrate using a patterning process includes:

[0049] Depositing a limiting structure film on one side of the substrate;

[0050] Applying a photoresist layer on a side of the limiting structure film facing away from the substrate;

[0051] exposing the photoresist layer using a mask including the limiting structure pattern;

[0052] Developing and removing the photoresist in the exposed area of ​​the photoresist layer;

[0053] Etching away the limiting structure film not covered by the photoresist by dry etching or wet etching to form patterns of the plurality of limiting structures;

[0054] The remaining photoresist is stripped off.

[0055] In some embodiments, the step of preparing a plurality of protrusions on one side of the substrate after completing the above steps by using a patterning process includes:

[0056] Applying an organic resin material layer on one side of the substrate;

[0057] exposing the organic resin material layer using a mask including the raised portion pattern;

[0058] The organic resin material in the exposed area of ​​the organic resin material layer is removed by development to form a pattern of the plurality of protrusions.

[0059] In some embodiments, the step of preparing the adjustable viscosity layer on the substrate side after completing the above steps by using a patterning process includes:

[0060] coating the adjustable viscosity layer on one side of the substrate by spin coating, blade coating or slit coating;

[0061] Alternatively, a viscosity-adjustable film is applied to one side of the substrate;

[0062] exposing the adjustable viscosity film using a mask including the adjustable viscosity layer pattern;

[0063] The adjustable viscosity film in the exposed area is removed by development to form a pattern of the adjustable viscosity layer.

[0064] In a fourth aspect, an embodiment of the present disclosure provides a mass transfer method, which includes: pressing a stamp with a transfer substrate;

[0065] The seal is the seal according to any one of claims 3 to 18; the transfer substrate comprises a base and a plurality of light-emitting diodes disposed on one side of the base; the plurality of raised portions in the seal correspond one-to-one with at least some of the light-emitting diodes; the adjustable viscosity layer, which overlaps with the orthographic projections of the raised portions on the base, contacts and adheres to the light-emitting diodes; and the orthographic projections of the raised portions on the base cover the light-emitting diodes.

[0066] The stamp is pulled in a direction away from the transfer substrate to pick up at least part of the light-emitting diodes in the transfer substrate;

[0067] The stamp transfers the picked-up LED to the drive substrate, and aligns the first connection end of the LED with the second connection end on the drive substrate. At the same time, pressure is applied to the stamp side and the drive substrate side is heated to complete the bonding between the first connection end and the second connection end.

[0068] The stamp is separated from the picked-up light-emitting diode.

[0069] In some embodiments, pressing the stamp and the transfer substrate and applying pressure to the stamp side include:

[0070] Mechanical compression;

[0071] Alternatively, the gas is pressurized.

[0072] In some embodiments, when gas pressure is applied, the stamp and the transfer substrate are bonded in a vacuum bonding device and sealed with a sealing adhesive, and under the action of external atmospheric pressure, the adjustable viscosity layer contacts and adheres to the light-emitting diode;

[0073] The stamp transfers the light-emitting diode to the driving substrate. The stamp and the driving substrate are bonded in a vacuum bonding device and sealed with a sealing adhesive. Under the action of external atmospheric pressure, the first connection end of the light-emitting diode contacts and bonds with the second connection end on the driving substrate.

[0074] Pressure is applied to the stamp side by gas pressurization, and the drive substrate side is heated, so that the first connection end and the second connection end are bonded.

[0075] In some embodiments, the stamp is separated from the picked-up light-emitting diode, comprising:

[0076] irradiating the side of the seal with UV light to separate the seal from the light-emitting diode;

[0077] Alternatively, the stamp side is heated, and when heated to 90-150° C., the stamp is separated from the light-emitting diode;

[0078] Alternatively, the seal side is irradiated with a laser to separate the seal from the light emitting diode;

[0079] The wavelength of the laser includes 255nm, 266nm, 308nm or 355nm.

[0080] In some embodiments, while the stamp is pulled away from the transfer substrate, a laser is irradiated on a position on the transfer substrate corresponding to the light-emitting diode to be picked up, so that the light-emitting diode to be picked up is separated from the base. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] The accompanying drawings are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. The above and other features and advantages will become more apparent to those skilled in the art by describing the detailed exemplary embodiments with reference to the accompanying drawings, in which:

[0082] Figure 1a is a schematic diagram of the van der Waals force seal transfer process and principle.

[0083] Figure 1b is a schematic cross-sectional view of the structure of the PDMS stamp.

[0084] Figure 1c is a schematic diagram of the displacement of the stamp structure relative to the glass substrate during the high-temperature and high-pressure eutectic bonding process.

[0085] FIG2 a is a schematic top view of the structure of a seal in an embodiment of the present disclosure.

[0086] FIG2 b is a schematic cross-sectional view of the seal structure along the AA′ section line in FIG2 a .

[0087] FIG. 2 c is a schematic cross-sectional view of another structure of the seal along the AA′ section line in FIG. 2 a .

[0088] FIG. 2 d is a schematic cross-sectional view of another structure of the seal along the AA′ section line in FIG. 2 a .

[0089] FIG2e is a schematic top view of the structure of another seal in an embodiment of the present disclosure.

[0090] FIG2f is a schematic top view of the structure of another seal in an embodiment of the present disclosure.

[0091] FIG2g is a schematic top view of the structure of another seal in an embodiment of the present disclosure.

[0092] FIG2h is a schematic top view of the structure of another seal in an embodiment of the present disclosure.

[0093] FIG2i is a schematic top view of the structure of another seal in an embodiment of the present disclosure.

[0094] FIG3 is a flow chart of a process for preparing a seal according to an embodiment of the present disclosure.

[0095] FIG4 a is a schematic diagram of a process of a mass transfer method according to an embodiment of the present disclosure.

[0096] FIG4 b is a process diagram of another mass transfer method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0097] In order to enable those skilled in the art to better understand the technical solutions of the embodiments of the present disclosure, a seal, a preparation method thereof, a transfer device and a mass transfer method provided by the embodiments of the present disclosure are further described in detail below in conjunction with the drawings and specific implementation methods.

[0098] The embodiments of the present disclosure will be described more fully below with reference to the accompanying drawings, but the illustrated embodiments may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully enable those skilled in the art to understand the scope of this disclosure.

[0099] The embodiments of the present disclosure are not limited to the embodiments shown in the drawings, but include modifications of the configurations formed based on the manufacturing process. Therefore, the regions illustrated in the drawings are schematic in nature, and the shapes of the regions shown in the drawings illustrate specific shapes of the regions, but are not intended to be limiting.

[0100] Micro-LED mass production still faces numerous challenges, with the most prominent technical bottlenecks being mass transfer and bonding. Micro-LED mass transfer involves electrostatic adsorption transfer, stamp transfer, and magnetic adsorption transfer. Currently, the most widely used transfer method is van der Waals stamp (PDMS) transfer, and the most widely used bonding method is eutectic bonding.

[0101] The van der Waals stamp transfer principle and process flow are shown in the figure below. The PDMS stamp itself has a certain degree of stickiness, and the degree of adhesion to the Micro-LED is adjusted by the lifting speed. Rapid lifting results in strong adhesion to the Micro-LED interface, enabling Micro-LED pickup. Slow lifting results in weak adhesion (adhesion less than the bonding force between the Micro-LED connector and the driver substrate connector), enabling Micro-LED placement and release.

[0102] Referring to Figure 1a, it is a schematic diagram of the van der Waals force stamp transfer process and principle; the elastic PDMS stamp 9 is aligned with the Micro-LED device 10 on the transfer substrate 6 and pressed down quickly; the PDMS stamp 9 deforms and fits tightly with the Micro-LED device 10; the PDMS stamp 9 is quickly lifted up to pull up the Micro-LED device 10; the PDMS stamp 9 carries the Micro-LED device 10 and is aligned with the driving substrate 7 and pressed down quickly; the PDMS stamp 9 slightly deviates to one side and is slowly lifted up; the PDMS stamp 9 recovers its deformation and separates from the Micro-LED device 10, completing the transfer of the Micro-LED device 10.

[0103] While Micro-LED transfer can be achieved through the van der Waals stamp (PDMS) transfer method, some technical issues still need to be resolved, such as: 1. The incompatibility between the PDMS stamp mass transfer technology and the eutectic bonding technology. Currently, the connection between the Micro-LED device and the driver substrate is mainly bonded using metal eutectic bonding technology. The main eutectic bonding schemes are shown in Table 1 below. Metal eutectic bonding requires high temperature and high pressure conditions, with a temperature range of 180-300°C. At high temperatures, the organic material PDMS stamp will age and its properties will change. Specifically, during the hot-pressing eutectic bonding process of the Micro-LED device, the stamp must be pressed continuously to provide bonding pressure. At high temperatures, PDMS stamp aging is inevitable. The aging of the PDMS stamp causes changes in its intrinsic adhesion, resulting in unstable yields in different batches of PDMS stamp transfer processes. 2. The problem of small size of single transfer of PDMS stamp; refer to Figure 1b, which is a schematic cross-sectional view of the structure of PDMS stamp; the PDMS stamp 9 is composed of a glass substrate 91 and a stamp structure 92 arranged on the glass substrate 91, and the stamp structure 92 includes a base material 921 and a protrusion 922 located on one side of the base material 921 and integrally formed with the base material 921. Large-scale driver substrates are a future product trend. The PDMS stamp currently corresponds to the transfer of a 4-inch driver substrate. When the size of the PDMS stamp increases, on the one hand, the uniformity of the height (i.e., thickness) of the stamp structure 92 itself decreases, and the transfer bonding yield decreases; on the other hand, referring to Figure 1c, which is a schematic diagram of the displacement of the stamp structure relative to the glass substrate during high-temperature and high-pressure eutectic bonding, the thermal expansion coefficient of the material of the stamp structure 92 (340 ppm / °C) is much larger than the thermal expansion coefficient of the glass substrate 91 (e.g., 3.5 ppm / °C). The difference in thermal expansion coefficients causes the PDMS stamp 9 to have a large cumulative displacement deviation relative to the glass substrate 91 during high-temperature and high-pressure eutectic bonding, thereby causing a large alignment deviation between the Micro-LED device connection end 101 and the driver substrate connection end 71; the larger the size of the PDMS stamp 9, the greater the decrease in transfer accuracy caused by the thermal expansion of the stamp structure 92 during the eutectic bonding process. The above reasons limit the PDMS stamp 9 to small-size transfer bonding, which is less efficient.

[0104] Table 1

[0105] In addition, the material cost and preparation cost of the PDMS stamp itself are relatively high, which greatly increases the cost of using PDMS stamps to transfer large quantities of Micro-LED devices.

[0106] In order to solve the problem that the above-mentioned PDMS stamp mass transfer technology is incompatible with the eutectic bonding technology and the PDMS stamp cannot achieve large-scale transfer, on the first hand, an embodiment of the present disclosure provides a stamp, referring to Figure 2a, which is a structural top view schematic diagram of a stamp in the embodiment of the present disclosure; Figure 2b is a structural sectional schematic diagram of the stamp along the AA' section line in Figure 2a; wherein, the stamp includes a substrate 1, a plurality of limiting structures 2, which are located on one side of the substrate 1 and are distributed at intervals; a plurality of transfer structures 3, which are located on the side of the substrate 1 where the limiting structures 2 are located and are distributed at intervals; the plurality of limiting structures 2 correspond one-to-one to the plurality of transfer structures 3, the limiting structures 2 surround the periphery of the transfer structures 3, and the orthographic projections of the limiting structures 2 and the transfer structures 3 on the substrate 1 do not overlap, and the distance h1 between the end face of the transfer structure 3 away from the substrate 1 and the substrate 1 is greater than the distance h2 between the end face of the limiting structure 2 away from the substrate 1 and the substrate 1.

[0107] Among them, the stamp can be used to transfer Micro-LED devices. The Micro-LED devices can be first fixed on the transfer substrate, and multiple transfer structures 3 perform one-to-one transfer of the Micro-LED devices on the transfer substrate to transfer the Micro-LED devices to the driving substrate. The distance h1 between the end face of the transfer structure 3 away from the substrate 1 and the substrate 1 is greater than the distance h2 between the end face of the limiting structure 2 away from the substrate 1 and the substrate 1. This is mainly to avoid direct contact between the limiting structure 2 and the driving substrate during the transfer of the Micro-LED device by the transfer structure 3, because the limiting structure 2 mainly plays a limiting role on the transfer structure 3. Contact between the limiting structure 2 and the driving substrate will affect the alignment and bonding of the Micro-LED device and the driving substrate.

[0108] By arranging multiple transfer structures 3 distributed at intervals on the substrate 1, the heights of the multiple transfer structures 3 prepared can be more consistent compared to the stamp structure in which the substrate and the protrusion are integrally formed in the related art, thereby making the height uniformity of the multiple transfer structures 3 better, which is beneficial to improving the transfer bonding yield of the Micro-LED device transferred by the stamp; by arranging multiple limiting structures 2, the limiting structure 2 can limit the position and lateral (i.e., in the direction parallel to the surface of the substrate 1) expansion of each transfer structure 3, so that the transfer structure 3 will not be laterally displaced relative to the substrate 1 due to thermal expansion during the high-temperature and high-pressure eutectic bonding process between the Micro-LED device connection end and the driving substrate connection end, thereby avoiding the occurrence of alignment deviation between the Micro-LED device connection end and the driving substrate connection end during the high-temperature and high-pressure eutectic bonding process; thereby improving the transfer bonding yield of the Micro-LED device transferred by the stamp; at the same time, based on the above two beneficial effects of the stamp, the stamp provided in the embodiment of the present disclosure can be prepared into a larger size, thereby improving the transfer bonding efficiency of the Micro-LED device transferred by the stamp.

[0109] In some embodiments, the transfer structure 3 includes a protrusion 31 and an adjustable viscosity layer 32. The protrusion 31 and the adjustable viscosity layer 32 are stacked one above the other, away from the substrate 1. The adjustable viscosity layer 32 and the orthographic projection of the protrusion 31 on the substrate 1 coincide with each other. The surface of the adjustable viscosity layer 32 facing away from the substrate 1 is configured to contact and adhere to the Micro-LED device. During the transfer process, the adjustable viscosity layer 32 can adhere to the Micro-LED device to facilitate pickup, and can also detach from the Micro-LED device to facilitate release. This allows the Micro-LED device to be transferred from the intermediate substrate to the driver substrate.

[0110] The presently disclosed embodiment also provides a seal, referring to Figure 2c, which is another structural cross-sectional schematic diagram of the seal along the AA' section line in Figure 2a, wherein the seal includes a substrate 1, a plurality of limiting structures 2, which are located on one side of the substrate 1 and are distributed at intervals; a plurality of protrusions 31, which are located on the side of the substrate 1 where the limiting structures 2 are located and are distributed at intervals; the plurality of limiting structures 2 correspond one-to-one to the plurality of protrusions 31, the limiting structures 2 surround the periphery of the protrusions 31, and the orthographic projections of the limiting structures 2 and the protrusions 31 on the substrate 1 do not overlap, and the distance h3 between the end face of the protrusion 31 away from the substrate 1 and the substrate 1 is greater than the distance h2 between the end face of the limiting structure 2 away from the substrate 1 and the substrate 1; an adjustable viscosity layer 32, which is located on the side of the limiting structure 2 and the protrusion 31 away from the substrate 1, and the orthographic projection of the adjustable viscosity layer 32 on the substrate 1 at least covers the protrusion 31.

[0111] The area of ​​the adjustable viscosity layer 32 facing away from the substrate 1 and where its orthographic projection on the substrate 1 overlaps with the orthographic projection of the protrusion 31 on the substrate 1 is used to contact and adhere to the Micro-LED device. During the transfer process, the adjustable viscosity layer 32 can adhere to the Micro-LED device to facilitate pickup, and can also detach from the Micro-LED device to facilitate release, thereby enabling transfer of the Micro-LED device from the transfer substrate to the driver substrate. The distance h3 between the end surface of the protrusion 31 facing away from the substrate 1 and the substrate 1 is greater than the distance h2 between the end surface of the retaining structure 2 facing away from the substrate 1 and the substrate 1. This is primarily to prevent direct contact between the retaining structure 2 and the driver substrate during transfer of the Micro-LED device between the protrusion 31 and the adjustable viscosity layer 32. The retaining structure 2 primarily serves to limit the protrusion 31. Contact between the retaining structure 2 and the driver substrate could affect the alignment and bonding of the Micro-LED device to the driver substrate.

[0112] By providing a plurality of raised portions 31 distributed at intervals on the substrate 1, the heights of the plurality of raised portions 31 prepared can be more consistent compared to the stamp structure in the related art in which the substrate and the raised portions are integrally formed, thereby making the height uniformity of the plurality of raised portions 31 better, which is beneficial to improving the transfer bonding yield of the Micro-LED device transferred using the stamp; by providing a plurality of limiting structures 2, the limiting structures 2 can limit the position and lateral (i.e., in the direction parallel to the surface of the substrate 1) expansion of each raised portion 31, so that the raised portion 31 will not be laterally displaced relative to the substrate 1 due to thermal expansion during the high-temperature and high-pressure eutectic bonding process between the Micro-LED device connection end and the drive substrate connection end, thereby avoiding the occurrence of alignment deviation between the Micro-LED device connection end and the drive substrate connection end during the high-temperature and high-pressure eutectic bonding process; thereby improving the transfer bonding yield of the Micro-LED device transferred using the stamp; at the same time, based on the above two beneficial effects of the stamp, the stamp provided in the embodiment of the present disclosure can be prepared in a larger size, thereby improving the transfer bonding efficiency of the Micro-LED device transferred using the stamp. At the same time, based on the above two beneficial effects of the stamp, the stamp provided in the embodiment of the present disclosure can be prepared into a larger size, thereby improving the transfer bonding efficiency of the Micro-LED device transferred using the stamp.

[0113] In some embodiments, referring to FIG. 2 a , the orthographic projection of the limiting structure 2 on the substrate 1 is annular, and the raised portion 31 is aligned with the orthographic projection of the limiting structure 2 on the substrate 1. With this arrangement, the limiting structure 2 can effectively limit the position and lateral (i.e., parallel to the surface of the substrate 1) expansion of the raised portion 31, preventing the raised portion 31 from lateral displacement relative to the substrate 1 due to thermal expansion during the high-temperature, high-pressure eutectic bonding process between the Micro-LED device connection end and the driver substrate connection end, thereby avoiding alignment deviation between the Micro-LED device connection end and the driver substrate connection end during the high-temperature, high-pressure eutectic bonding process, thereby improving the transfer bonding yield of the Micro-LED device using this stamp.

[0114] In some embodiments, referring to Figure 2c, 1 / 3 of the height of the protrusion 31 ≤ the height of the limiting structure 2 ≤ 3 / 4 of the height of the protrusion 31. In this way, the limiting structure 2 can not only effectively limit the position of the protrusion 31 and the lateral expansion (i.e., in the direction parallel to the surface of the substrate 1) of the protrusion 31, but also avoid direct contact between the limiting structure 2 and the driving substrate, because the limiting structure 2 mainly limits the protrusion 31. The contact between the limiting structure 2 and the driving substrate will affect the alignment and bonding of the Micro-LED device and the driving substrate. Among them, the height of the protrusion 31 is the distance h3 between the end face of the protrusion 31 away from the substrate 1 and the substrate 1. The height of the limiting structure 2 is the distance h2 between the end face of the limiting structure 2 away from the substrate 1 and the substrate 1.

[0115] In some embodiments, the height of the protrusions 31 ranges from 5 to 20 μm. The height of the protrusions 31 is defined as the thickness of the protrusions 31 along the direction away from the substrate 1. This height range ensures uniform height across the multiple protrusions 31 on the substrate 1. Furthermore, the combination of the protrusions 31 and the adjustable viscosity layer 32 ensures efficient transfer of Micro-LED devices, improving transfer yield.

[0116] In some embodiments, the width a of the ring surface of the limiting structure 2 ranges from 2 to 30 μm. This range of the ring surface width a ensures that the limiting structure 2 stably limits the position and lateral expansion (i.e., in a direction parallel to the surface of the substrate 1) of the protrusion 31 .

[0117] In some embodiments, the thickness of the adjustable viscosity layer 32 is in the range of 1 to 5 μm. The adjustable viscosity layer 32 in this thickness range can effectively pick up and release the Micro-LED device, thereby effectively transferring the Micro-LED device from the transfer substrate to the driving substrate.

[0118] In some embodiments, referring to Figure 2d, another schematic cross-sectional view of the stamp structure along the AA' section line in Figure 2a is shown. The adjustable viscosity layer 32 includes a viscous sublayer 322 and a deionizing layer 321. The deionizing layer 321 and the viscous sublayer 322 are stacked sequentially away from the substrate 1. The thickness of the viscous sublayer 322 ranges from 1 to 5 μm, while the thickness of the deionizing layer 321 ranges from 0.1 to 2 μm. The viscous sublayer 322 can be attached and picked up by the adhesive material, while the deionizing layer 321 can be released by debonding the material, thereby enabling the pickup and release of the Micro-LED device, thereby effectively transferring the Micro-LED device from the transfer substrate to the driver substrate.

[0119] In some embodiments, referring to Figures 2a, 2e and 2f, Figure 2e is a schematic top view of the structure of another seal in an embodiment of the present disclosure; Figure 2f is a schematic top view of the structure of yet another seal in an embodiment of the present disclosure; wherein, the orthographic projection shape of the raised portion 31 on the substrate 1 includes a circle, a rectangle, a triangle or a polygon.

[0120] In some embodiments, referring to Figures 2a, 2e and 2f, a plurality of raised portions 31 are arranged in an array at equal intervals; referring to Figure 2g, which is a schematic top view of the structure of another seal in the present disclosure embodiment; the orthographic projection shapes of the plurality of raised portions 31 on the substrate 1 are the same, and the directions of the orthographic projection figures of any two adjacent columns of raised portions 31 on the substrate 1 are different; as shown in Figure 2g, the orthographic projection shapes of the plurality of raised portions 31 on the substrate 1 are all triangles, and the directions of the orthographic projection triangles of any two adjacent columns of raised portions 31 on the substrate 1 are different; referring to Figure 2h, which is a schematic top view of the structure of another seal in the present disclosure embodiment; the orthographic projection shape of a portion of the plurality of raised portions 31 on the substrate 1 is different from the orthographic projection shape of another portion on the substrate 1. As shown in Figure 2h, the orthographic projection shape of a portion of the plurality of raised portions 31 on the substrate 1 is rectangular, and the orthographic projection shape of the other portion on the substrate 1 is circular.

[0121] In some embodiments, referring to Figure 2i, which is a schematic top view of the structure of another seal in the embodiment of the present disclosure; a part of the multiple raised portions 31 are arranged in an array with a first interval b1, and another part are arranged in an array with a second interval b2, and the first interval b1 is larger than the second interval b2.

[0122] In some embodiments, the material of the protrusion 31 includes any one of acrylic resin, propylene glycol methyl ether acetate, silicone resin, and acrylic resin.

[0123] In some embodiments, the material of the limiting structure 2 includes any one of silicon oxide, silicon nitride, silicon oxynitride, copper, aluminum, molybdenum, and silver.

[0124] In some embodiments, the material of the adjustable viscosity layer 32 includes any one of UV-viscosity-reducing glue, thermal foaming-based adhesive, and laser-debonding adhesive. The main material of the UV-viscosity-reducing glue includes any one of epoxy acrylate, polyurethane acrylate, polyether acrylate, polyester acrylate, and acrylic resin. The main material of the thermal foaming-based adhesive includes one or more of styrene-butadiene rubber, polyisoprene rubber, polyisobutylene, butyl rubber, and synthetic rubbers such as chloroprene rubber and nitrile rubber. The main material of the thermal foaming-based adhesive includes foamed particles, with a particle size range of 0.5-5 μm and a filling ratio of 2% to 10% in the main material. The main material of the laser-debonding adhesive includes one or more of acrylic resin, epoxy resin, and acrylic resin. UV-viscosity-reducing glue has certain adhesive properties and can be debonded under UV light. Thermal foaming-based adhesive has certain adhesive properties and can be debonded under heating. Laser-debonding adhesive has certain adhesive properties and can be debonded under laser light.

[0125] In some embodiments, the main material of the adhesive sublayer 322 includes one or more of polyether resin, epoxy resin, acrylic resin, polyisoprene resin, and polyisobutylene resin; the main material of the deionizing layer 321 includes one or more of polyimide, acrylic, epoxy, and other resins. The main material used in the deionizing layer 321 is a laser decomposition adhesive, which has no adhesive properties but only laser decomposition properties. When irradiated by a 255, 266, 308, or 355 nm laser, the main material of the deionizing layer 321 breaks its molecular chains and produces gas, achieving the dissociation of the film layers located on both sides. The adhesive sublayer 322 has certain adhesive properties, enabling adhesion and bonding between the protrusion 31 and the Micro-LED device.

[0126] In some embodiments, referring to Figures 2b, 2c and 2d, the seal also includes a plurality of alignment marks 4, which are located on the side of the substrate 1 where the limiting structure 2 is located, and are located in the peripheral area or the middle area of ​​the substrate 1. The alignment marks 4 do not overlap with the orthographic projections of the limiting structure 2 and the raised portion 31 on the substrate 1; the alignment marks 4 are located on the side of the adjustable viscosity layer 32 close to the substrate 1.

[0127] Among them, the alignment mark 4 is used to align the protrusion 31 with the Micro-LED device when the seal picks up the Micro-LED device from the transfer substrate, and is also used to align the connection end of the Micro-LED device with the connection end on the driving substrate when the seal transfers the Micro-LED device to the driving substrate.

[0128] In some embodiments, the alignment mark 4 is made of a metal material, such as molybdenum, titanium, aluminum, or silver. In some embodiments, the orthographic projection of the alignment mark 4 on the substrate 1 may be rectangular, circular, or cross-shaped. The size of the alignment mark 4 can be determined based on the recognition accuracy of the alignment equipment used and is not specifically limited.

[0129] Secondly, based on the above-mentioned structure of the seal, the embodiment of the present disclosure also provides a method for preparing the seal. Referring to Figure 3, it is a flow chart of the preparation process of a seal in the embodiment of the present disclosure; wherein, it includes: step S102: using a composition process to prepare multiple limiting structures 2 on one side of the substrate 1.

[0130] Step S103 : Using a patterning process, a plurality of protrusions 31 are formed on one side of the substrate 1 after the above steps are completed. The plurality of protrusions 31 and the plurality of limiting structures 2 are located on the same side of the substrate 1 .

[0131] Step S104: Using a patterning process, a viscosity-adjustable layer 32 is formed on the side of the substrate 1 that has undergone the above steps. The viscosity-adjustable layer 32 is located on the side of the limiting structure 2 and the protrusion 31 that faces away from the substrate 1. The orthographic projection of the viscosity-adjustable layer 32 on the substrate 1 at least covers the protrusion 31.

[0132] In this embodiment, before step S102, step S101 is further included: a patterning process is used to form a plurality of alignment marks 4 on one side of the substrate 1. The patterning process for forming the alignment marks 4 includes film deposition, photoresist coating, exposure, development, etching and other steps, which will not be repeated here.

[0133] The preparation method of the seal in the embodiment of the present disclosure is realized through a traditional composition process. The preparation process is simple, the preparation precision is high, the preparation cost is low, and large-size seals can be prepared. The prepared seal can not only improve the transfer bonding yield of the Micro-LED device, but also improve the transfer bonding efficiency of the Micro-LED device.

[0134] In some embodiments, step S102 : preparing a plurality of limiting structures 2 on one side of the substrate 1 by using a patterning process, including: step S1021 : depositing a limiting structure film on one side of the substrate.

[0135] In this step, when the limiting structure film adopts inorganic insulating materials such as silicon nitride, silicon oxide or silicon oxynitride, the limiting structure film is formed by chemical vapor deposition; when the limiting structure film adopts metal materials such as copper, aluminum, molybdenum or silver, the limiting structure film is formed by sputtering deposition.

[0136] Step S1022: applying a photoresist layer on the side of the limiting structure film facing away from the substrate.

[0137] Step S1023: using a mask plate including a limiting structure pattern to expose the photoresist layer.

[0138] Step S1024: developing and removing the photoresist in the exposed area of ​​the photoresist layer.

[0139] In this step, the photoresist layer in the area outside the limiting structure pattern is removed by development.

[0140] Step S1025: etching away the limiting structure film not covered by the photoresist by dry etching or wet etching to form a pattern of multiple limiting structures.

[0141] In this step, the limiting structure film of the inorganic insulating material is removed by dry etching, and the limiting structure film of the metal material is removed by wet etching.

[0142] Step S1026: stripping off the remaining photoresist.

[0143] In some embodiments, step S103: using a patterning process to prepare a plurality of protrusions 31 on one side of the substrate 1 after completing the above steps, including: coating an organic resin material layer on one side of the substrate.

[0144] The organic resin material layer is exposed using a mask including a pattern of protrusions.

[0145] The organic resin material in the exposed area of ​​the organic resin material layer is removed by development to form a pattern of a plurality of protrusions.

[0146] In some embodiments, step S104: forming the viscosity adjustable layer 32 on one side of the substrate 1 after completing the above steps by using a patterning process, including: coating the viscosity adjustable layer on one side of the substrate by spin coating, blade coating or slit coating.

[0147] The viscosity-adjustable layer is a whole layer covering the substrate.

[0148] In some embodiments, step S104: using a patterning process to prepare the viscosity adjustable layer 32 on one side of the substrate 1 after completing the above steps, including: coating a viscosity adjustable film on one side of the substrate.

[0149] The viscosity adjustable film is exposed using a mask including a viscosity adjustable layer pattern.

[0150] The development removes the adjustable viscosity film from the exposed area of ​​the adjustable viscosity film to form a pattern of an adjustable viscosity layer, wherein the orthographic projection of the adjustable viscosity layer on the substrate does not overlap with the substrate, partially overlaps with the substrate, and covers at least the orthographic projection of the protrusion on the substrate.

[0151] On the third aspect, the embodiment of the present disclosure also provides a mass transfer method. Referring to Figure 4a, it is a process schematic diagram of a mass transfer method in the embodiment of the present disclosure; Figure 4b is a process schematic diagram of another mass transfer method in the embodiment of the present disclosure; which includes: Step S201: pressing the seal 5 and the transfer substrate 6.

[0152] Among them, the seal 5 is the seal in the above embodiment; the transfer substrate 6 includes a base 61 and a plurality of light-emitting diodes 62 arranged on one side of the base 61, the plurality of protrusions 31 in the seal 5 correspond one-to-one to at least some of the light-emitting diodes 62, the adjustable viscosity layer 32 overlapping with the orthographic projection of the protrusion 31 on the base 61 is in contact with and bonded to the light-emitting diodes 62, and the orthographic projection of the protrusion 31 on the base 61 covers the light-emitting diodes 62.

[0153] In some embodiments, the light-emitting diode 62 may be a normal-sized light-emitting diode (ie, LED), or a micro light-emitting diode (ie, Micro-LED) or a mini light-emitting diode (ie, Mini-LED).

[0154] In some embodiments, the pressing of the stamp 5 and the transfer substrate 6 includes: mechanical pressurization (refer to FIG. 4 a ); or gas pressurization (refer to FIG. 4 b ).

[0155] In some embodiments, referring to FIG. 4 b , when gas pressurization is applied, the stamp 5 and the transfer substrate 6 are bonded in a vacuum bonding device and sealed with a frame sealant 8 . Under the action of external atmospheric pressure, the adjustable viscosity layer 32 contacts and bonds with the light-emitting diode 62 .

[0156] Step S202 : the stamp 5 is pulled away from the transfer substrate 6 to pick up at least part of the light emitting diodes 62 in the transfer substrate 6 .

[0157] In this step, the seal 5 is adhered to the light-emitting diode 62 through the viscosity-adjustable layer 32 or the viscosity sublayer 322 in the viscosity-adjustable layer 32. When the seal 5 is pulled away from the transfer substrate 6, the adhesion force between the viscosity-adjustable layer 32 or the viscosity sublayer 322 and the light-emitting diode 62 is greater than the bonding force between the light-emitting diode 62 and the base 61, thereby separating the light-emitting diode 62 from the base 61 and realizing the picking up of the light-emitting diode 62.

[0158] In some embodiments, while the stamp 5 is pulled away from the transfer substrate 6, a laser is irradiated on the side of the transfer substrate 6 corresponding to the position of the LED 62 to be picked up, thereby separating the LED 62 to be picked up from the base 61. That is, the LED 62 and the base 61 are fixedly connected by a laser-detachable material (such as a laser-detachable adhesive). When the stamp 5 picks up the LED 62 from the transfer substrate 6, the laser is irradiated on the side of the transfer substrate 6, thereby separating the LED 62 from the base 61.

[0159] Step S203: The stamp 5 transfers the picked-up light-emitting diode 62 to the driving substrate 7, and makes the first connection end 620 of the light-emitting diode 62 fit correspondingly with the second connection end 70 on the driving substrate 7. At the same time, pressure is applied to the side of the stamp 5, and the side of the driving substrate 7 is heated to complete the bonding of the first connection end 620 and the second connection end 70.

[0160] In some embodiments, referring to FIG. 4 b , this step includes step S203′: the stamp 5 transfers the light-emitting diode 62 to the driver substrate 7. The stamp 5 and the driver substrate 7 are bonded in a vacuum bonding apparatus and sealed with a frame sealant 8. Under the influence of external atmospheric pressure, the first connection end 620 of the light-emitting diode 62 contacts and bonds with the second connection end 70 on the driver substrate 7. Step S203″: applying pressure to the stamp 5 through gas pressurization and heating the driver substrate 7 to achieve bonding between the first connection end 620 and the second connection end 70.

[0161] In some embodiments, the pressure applied to the stamp 5 refers to the pressure values ​​in Table 1; the heating temperature applied to the drive substrate 7 refers to the temperature values ​​in Table 1. Under the pressure and heating process conditions in Table 1, the first connecting end 620 and the second connecting end 70 complete eutectic bonding.

[0162] In some embodiments, there are two first connection ends 620 and two second connection ends 70 , and the two first connection ends 620 and the two second connection ends 70 are connected in a one-to-one correspondence.

[0163] Step S204 : the stamp 5 is separated from the picked-up light-emitting diode 62 .

[0164] In this step, when the viscosity-adjustable layer 32 or the deionizing layer uses UV-reducing glue, the side of the seal 5 is irradiated with UV light to separate the seal 5 from the light-emitting diode 62 .

[0165] In some embodiments, when the viscosity-adjustable layer 32 or the deionized layer uses heat-foaming viscosity-reducing glue, the side of the seal 5 is heated. When heated to 90-150° C., the seal 5 is separated from the light-emitting diode 62.

[0166] In some embodiments, when the viscosity adjustable layer 32 or the deionizing layer uses laser debonding adhesive, the stamp 5 is irradiated with laser to separate the stamp 5 from the light emitting diode 62. The wavelength of the laser includes 255nm, 266nm, 308nm or 355nm.

[0167] The mass transfer method provided by the embodiment of the present disclosure, by adopting the stamp in the above embodiment, can not only realize the batch and multiple transfer of light-emitting diodes in the transfer substrate, but also realize the one-time transfer of multiple light-emitting diodes in the transfer substrate, thereby not only improving the transfer bonding yield of the light-emitting diodes, but also improving the transfer bonding efficiency of the light-emitting diodes.

[0168] In a fourth aspect, an embodiment of the present disclosure further provides a transfer device, comprising the seal in the above embodiment.

[0169] The transfer equipment can perform mass transfer of light-emitting diodes (LEDs), micro light-emitting diodes (Micro-LEDs) and mini light-emitting diodes (Mini-LEDs).

[0170] By adopting the stamp in the above embodiment, the transfer device can realize a one-time transfer of the light-emitting diodes on the transfer substrate, thereby improving not only the transfer bonding yield of the transfer device but also the transfer bonding efficiency of the transfer device.

[0171] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A seal, wherein Including substrate, A plurality of limiting structures are located on one side of the substrate and are distributed at intervals; A plurality of transfer structures are located on one side of the substrate where the limiting structure is located and are distributed at intervals; The plurality of limiting structures correspond one to one with the plurality of transfer structures, The limiting structure surrounds the periphery of the transfer structure, and the orthographic projections of the limiting structure and the transfer structure on the substrate do not overlap. A distance between an end surface of the transfer structure away from the substrate and the substrate is greater than a distance between an end surface of the limiting structure away from the substrate and the substrate.

2. The seal according to claim 1, wherein: The transfer structure comprises a protrusion and an adjustable viscosity layer, wherein the protrusion and the adjustable viscosity layer are stacked in sequence away from the substrate. The adjustable viscosity layer coincides with an orthographic projection of the protrusion on the substrate.

3. A seal, wherein: Including substrate, A plurality of limiting structures are located on one side of the substrate and are distributed at intervals; A plurality of protrusions are located on one side of the substrate where the limiting structure is located and are distributed at intervals; The plurality of limiting structures correspond to the plurality of protrusions one by one, The limiting structure surrounds the outer periphery of the protruding portion, and the limiting structure and the orthographic projection of the protruding portion on the substrate do not overlap, The distance between the end surface of the protrusion away from the substrate and the substrate is greater than the distance between the end surface of the limiting structure away from the substrate and the substrate; The viscosity-adjustable layer is located on a side of the limiting structure and the protrusion away from the substrate, and the orthographic projection of the viscosity-adjustable layer on the substrate at least covers the protrusion.

4. The seal according to claim 2 or 3, wherein: The orthographic projection shape of the limiting structure on the substrate is a ring. The protrusion and the limiting structure are butted against each other in an orthographic projection pattern on the substrate.

5. The seal according to claim 2 or 3, wherein: 1 / 3 of the height of the protruding portion ≤ the height of the limiting structure ≤ 3 / 4 of the height of the protruding portion.

6. The seal according to claim 5, wherein: The height of the protrusion is in the range of 5 to 20 μm.

7. The seal according to claim 4, wherein: The width of the annular surface of the limiting structure is in the range of 2 to 30 μm.

8. The seal according to claim 2 or 3, wherein: The thickness of the adjustable viscosity layer is in the range of 1 to 5 μm.

9. The seal according to claim 2 or 3, wherein: The adjustable viscosity layer comprises a viscosity sublayer and an ion-degrading layer, wherein the ion-degrading layer and the viscosity sublayer are sequentially stacked away from the substrate; The thickness of the adhesive sublayer ranges from 1 to 5 μm; The thickness of the deionizing layer is in the range of 0.1 to 2 μm.

10. The seal according to claim 2 or 3, wherein: The orthographic projection shape of the protrusion on the substrate includes a circle, a rectangle, a triangle or a polygon.

11. The seal according to claim 10, wherein: The plurality of protrusions are arranged in an array at equal intervals; The orthographic projection shapes of the plurality of protrusions on the substrate are the same, and the directions of the orthographic projection shapes of any two adjacent rows of the protrusions on the substrate are different; Alternatively, the orthographic projection shape of a portion of the plurality of protrusions on the substrate is different from the orthographic projection shape of another portion of the plurality of protrusions on the substrate.

12. The seal according to claim 10, wherein: A portion of the plurality of protrusions are arranged in an array at a first interval, and another portion are arranged in an array at a second interval, wherein the first interval is greater than the second interval.

13. The seal according to claim 2 or 3, wherein: The material of the protrusion includes any one of acrylic resin, propylene glycol methyl ether acetate, silicone resin and acrylic resin.

14. The seal according to any one of claims 1 to 3, wherein: The material of the limiting structure includes any one of silicon oxide, silicon nitride, silicon oxynitride, copper, aluminum, molybdenum and silver.

15. The seal according to claim 2 or 3, wherein: The material of the adjustable viscosity layer includes any one of UV viscosity reducing glue, thermal foaming viscosity reducing glue and laser dissociation glue; The main material of the UV viscosity-reducing glue includes any one of epoxy acrylate, polyurethane acrylate, polyether acrylate, polyester acrylate, and acrylic resin; The main material of the hot foaming viscosity-reducing glue includes one or more of styrene-butadiene rubber, polyisoprene rubber, polyisobutylene and butyl rubber, as well as chloroprene rubber, nitrile rubber and other synthetic rubbers. The main material of the hot foaming viscosity-reducing glue is mixed with foaming particles, the particle size range of the foaming particles is 0.5-5 μm, and the filling rate of the foaming particles in the main material is 2% to 10%; The main material of the laser dissociation adhesive includes one or more of acrylic resin, epoxy resin and acrylic resin.

16. The seal according to claim 9, wherein: The main material of the adhesive sublayer includes one or more of polyether resin, epoxy resin, acrylic resin, polyisoprene resin, and polyisobutylene resin; The main material of the deionizing layer includes one or more resins such as polyimide, acrylic acid, and epoxy.

17. The seal according to claim 2 or 3, wherein: It also includes a plurality of alignment marks, which are located on one side of the substrate where the limiting structure is located, and are located in the peripheral area or the middle area of ​​the substrate. The alignment mark does not overlap with the orthographic projections of the limiting structure and the protruding portion on the substrate; The alignment mark is located on a side of the adjustable viscosity layer close to the substrate.

18. A transfer device, wherein: A seal comprising the seal described in any one of claims 1 to 17.

19. A method for preparing a seal, wherein: include: A plurality of limiting structures are prepared on one side of the substrate by using a patterning process; A plurality of protrusions are prepared on one side of the substrate after the above steps by using a patterning process; the plurality of protrusions and the plurality of limiting structures are located on the same side of the substrate; A viscosity adjustable layer is prepared on one side of the substrate after completing the above steps by using a patterning process; the viscosity adjustable layer is located on the side of the limiting structure and the protrusion away from the substrate, and the orthographic projection of the viscosity adjustable layer on the substrate at least covers the protrusion.

20. The method for preparing a seal according to claim 19, wherein: The method of using a patterning process to prepare a plurality of limiting structures on one side of the substrate includes: Depositing a limiting structure film on one side of the substrate; Applying a photoresist layer on the side of the limiting structure film facing away from the substrate; Exposing the photoresist layer using a mask plate including the limiting structure pattern; Developing and removing the photoresist in the exposed area of ​​the photoresist layer; Etching and removing the limiting structure film not covered by the photoresist by dry etching or wet etching to form patterns of the plurality of limiting structures; The remaining photoresist is stripped off.

21. The method for preparing a seal according to claim 19, wherein: The method of using a patterning process to prepare a plurality of protrusions on one side of the substrate after completing the above steps comprises: Applying an organic resin material layer on one side of the substrate; Exposing the organic resin material layer using a mask plate including the raised portion pattern; The organic resin material in the exposed area of ​​the organic resin material layer is removed by development to form a pattern of the plurality of protrusions.

22. The method for preparing a seal according to claim 19, wherein: The method of using a patterning process to prepare an adjustable viscosity layer on one side of the substrate after completing the above steps comprises: The adjustable viscosity layer is formed by coating on one side of the substrate by spin coating, blade coating or slit coating; Alternatively, a viscosity adjustable film is applied to one side of the substrate; Exposing the adjustable viscosity film using a mask plate including the adjustable viscosity layer pattern; The adjustable viscosity film in the exposed area of ​​the adjustable viscosity film is removed by development to form a pattern of the adjustable viscosity layer.

23. A method for mass transfer, wherein: include: The seal is pressed with the transfer substrate; The seal is a seal according to any one of claims 3 to 18; the transfer substrate comprises a base and a plurality of light emitting diodes arranged on one side of the base, and the plurality of convex The raised portions correspond to at least a portion of the light-emitting diodes one by one, the adjustable viscosity layer overlapping with the orthographic projection of the raised portions on the substrate contacts and adheres to the light-emitting diodes, and the orthographic projection of the raised portions on the substrate covers the light-emitting diodes; The stamp is pulled in a direction away from the transfer substrate to pick up at least part of the light emitting diodes in the transfer substrate; The stamp transfers the picked-up light-emitting diode to the driving substrate, and makes the first connection end of the light-emitting diode fit with the second connection end on the driving substrate, and at the same time applies pressure to the stamp side and heats the driving substrate side, so that the first connection end and the second connection end are bonded; The stamp is detached from the picked-up light emitting diode.

24. The method for mass transfer according to claim 23, wherein: The pressing of the stamp and the transfer substrate and the applying of pressure to the stamp side include: Mechanical pressurization; Alternatively, the gas is pressurized.

25. The method for mass transfer according to claim 24, wherein: When the gas is pressurized, the stamp and the transfer substrate are attached to each other in a vacuum attaching device and sealed by a sealing glue, and under the action of the external atmospheric pressure, the adjustable viscosity layer contacts and adheres to the light emitting diode; The stamp transfers the light-emitting diode to the driving substrate, the stamp and the driving substrate are bonded in a vacuum bonding device and sealed with a sealing glue, and under the action of the external atmospheric pressure, the first connection end of the light-emitting diode contacts and bonds with the second connection end on the driving substrate; The stamp side is pressurized by gas and the drive substrate side is heated to complete the bonding of the first connection end and the second connection end.

26. The method for mass transfer according to claim 23, wherein: The stamp is separated from the picked-up light-emitting diode, comprising: irradiating the seal side with UV light to separate the seal from the light emitting diode; Alternatively, the stamp side is heated, and when heated to 90-150° C., the stamp is separated from the light-emitting diode; Alternatively, the seal side is irradiated with a laser to separate the seal from the light emitting diode; Wherein, the wavelength of the laser includes 255nm, 266nm, 308nm or 355nm.

27. The mass transfer method according to claim 23, wherein: When the stamp is pulled away from the transfer substrate, the position of the transfer substrate corresponding to the light emitting diode to be picked up is irradiated with laser, so that the light emitting diode to be picked up is separated from the base.

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