Method for transferring LED chip and LED chip

Abstract

An embodiment of the present application provides a method for transferring an LED chip and an LED chip. The method for transferring the LED chip includes: providing a substrate and a temporary substrate; wherein, an adhesive layer is formed on the temporary substrate; preparing an LED chip on the substrate; connecting a surface of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate, and embedding at least part of the structure of the LED chip in the adhesive layer; separating the substrate from the LED chip. The method for transferring the LED chip effectively improves the peeling yield of the LED chip.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor LED chips, and particularly to a method for transferring an LED chip and an LED chip. Background Art

[0002] With the development of flat panel display and micro-projection display technologies, Micro-LED light-emitting diode technology has been widely used in fields such as display screens, visible light communication, and intelligent portable devices due to its advantages of low power consumption, high brightness, high definition, and long lifespan.

[0003] Among them, in the manufacturing process of Micro-LED, the structural design of the LED chip is a key link to improve the light extraction efficiency of the LED. Currently, the mainstream structural forms of LED chips include front-mounted LED chips, flip-chip LED chips, and vertical LED chips. However, the yield of existing flip-chip LED chips is relatively low after laser lift-off. Summary of the Invention

[0004] The method for transferring an LED chip and the LED chip provided in this application aim to solve the problem of relatively low yield of LED chips after laser lift-off of existing flip-chip LED chips.

[0005] To solve the above technical problems, a technical solution adopted in this application is: to provide a method for transferring an LED chip. The method includes: providing a substrate and a temporary substrate; wherein, an adhesive layer is formed on the temporary substrate; preparing an LED chip on the substrate; connecting a surface of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate, and embedding at least part of the structure of the LED chip in the adhesive layer; separating the substrate from the LED chip.

[0006] By embedding at least part of the structure of the LED chip in the adhesive layer as described above, not only the connection strength between the LED chip and the temporary substrate is effectively improved, but also the LED chip can be protected by the adhesive layer and the position of the LED chip can be fixed, so as to avoid the problems of fracture or deflection of the LED chip during the subsequent process of separating the substrate from the LED chip, thereby effectively improving the lift-off yield of the LED chip.

[0007] Among them, the step of preparing the LED chip on the substrate specifically includes: forming an epitaxial layer on the substrate; wherein, the epitaxial layer has a first-type well region and a second-type well region; forming an insulating reflective layer on a surface of the epitaxial layer facing away from the substrate, and opening holes in the insulating reflective layer to expose at least the first-type well region and the second-type well region of the epitaxial layer; forming a first electrode and a second electrode in the first-type well region and the second-type well region of the epitaxial layer respectively to obtain the LED chip.

[0008] The above method embeds partial structures of the first electrode and the second electrode of the LED chip into the opening structure of the insulating reflective layer, making it possible for the Micro LED chip to use the inorganic DBR reflective layer to improve the light efficiency. At the same time, the first electrode and the second electrode can be protected by the insulating reflective layer, and the first electrode and the second electrode can be limited in position.

[0009] Among them, after the first electrode and the second electrode are respectively formed in the first-type well region and the second-type well region of the epitaxial layer, partial regions of the first-type well region and / or partial regions of the second-type well region are exposed through the openings. The step of connecting the surface of the side of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate and embedding at least part of the structure of the LED chip in the adhesive layer specifically includes: connecting the surface of the side of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate, and embedding at least part of the structure of the insulating reflective layer in the adhesive layer, and the adhesive layer is filled in the openings.

[0010] The above method can fill the adhesive layer in the openings of the insulating reflective layer to form an adhesive column. This can not only further fix the position of the LED chip, prevent the LED chip from deflecting during the peeling process from the substrate, but also ensure the regular shape consistency of the subsequent remaining adhesive column, so as to facilitate the picking up of the LED chip.

[0011] Among them, after the step of separating the substrate from the LED chip, it further includes: removing the adhesive layer wrapping the LED chip, and spacing the insulating reflective layer of the LED chip from the adhesive layer.

[0012] This can reduce the connection strength between the LED chip and the adhesive layer, facilitate the subsequent picking up of the LED chip, and thus improve the picking yield of the LED chip.

[0013] Among them, the step of removing the adhesive layer wrapping the LED chip and spacing the insulating reflective layer of the LED chip from the adhesive layer specifically includes: removing the adhesive layer around the LED chip along the first direction by means of collimated etching until all of the LED chip is exposed; removing the adhesive layer on the side of the insulating reflective layer facing away from the epitaxial layer along the second direction by means of isotropic etching to space the insulating reflective layer from the adhesive layer; wherein, the first direction and the second direction are perpendicular.

[0014] The above method weakens the adhesion force between the LED chip and the glue layer on the temporary substrate by combining collimated etching and isotropic etching, and combines the special structure of the LED chip to make the shape and size of the glue column under the LED chip more uniform after etching; moreover, the pick-up yield of the LED chip is greatly improved; at the same time, the process is simple, more feasible for mass production, effectively reduces the difficulty of mass transfer, and further improves the transfer yield of the LED chip.

[0015] Wherein, the insulating reflective layer is a DBR reflective layer.

[0016] This can greatly improve the light efficiency of the LED chip.

[0017] Wherein, the step of forming the epitaxial layer on the substrate specifically includes: sequentially growing a nucleation layer, a buffer layer, an N-semiconductor layer, a multi-quantum well layer, and a P-semiconductor layer on the substrate to form an epitaxial layer; processing the surface of the epitaxial layer facing away from the substrate to form a first type well region and a second type well region.

[0018] The above method can ensure the effective light emission of the LED chip.

[0019] To solve the above technical problems, another technical solution adopted by the present application is: to provide an LED chip. The LED chip includes: an epitaxial layer, an insulating reflective layer, a first electrode, and a second electrode; wherein, the epitaxial layer has a first type well region and a second type well region; the insulating reflective layer is disposed on the surface of the epitaxial layer having the first type well region and the second type well region and surrounds the first type well region and the second type well region, and a communication hole is formed within the surrounded area of the insulating reflective layer; the first electrode is embedded in the communication hole and is located in the first type well region; the second electrode is embedded in the communication hole and is located in the second type well region.

[0020] By embedding the first electrode and the second electrode of the LED chip in the communication holes of the insulating reflective layer as described above, it becomes possible for the Micro LED chip to use an inorganic DBR reflective layer to improve the light efficiency.

[0021] Wherein, the insulating reflective layer is a DBR reflective layer.

[0022] This can greatly improve the light efficiency of the LED chip.

[0023] Wherein, the first electrode and / or the second electrode is disposed in contact with the insulating reflective layer.

[0024] This can prevent the glue layer from entering the gap between the first electrode and / or the second electrode and the insulating reflective layer, making it easier to etch away the glue layer around the LED chip.

[0025] The transfer method of an LED chip and the LED chip provided by an embodiment of the present application. The method includes providing a substrate and a temporary substrate, then fabricating an LED chip on the substrate; after that, connecting the surface of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate, and embedding at least part of the structure of the LED chip in the adhesive layer; finally, separating the substrate from the LED chip. Among them, since at least part of the structure of the LED chip is embedded in the adhesive layer, that is, the adhesive layer wraps at least part of the structure of the LED chip, this not only effectively improves the connection strength between the LED chip and the temporary substrate, but also can protect the LED chip through the adhesive layer and fix the position of the LED chip, so as to avoid the problems of fracture or deflection of the LED chip during the subsequent peeling process of the substrate from the LED chip, thereby effectively improving the peeling yield of the LED chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings, where:

[0027] Figure 1a is a flowchart of the transfer method of the LED chip provided by an embodiment of the present application;

[0028] Figure 1b is a schematic structural diagram of a substrate provided by an embodiment of the present application;

[0029] Figure 1c is a schematic structural diagram of a temporary substrate provided by an embodiment of the present application;

[0030] Figure 2 is Figure 1a a sub-flowchart of step S2 in

[0031] Figure 3 is a schematic structural diagram of an epitaxial layer formed on a substrate;

[0032] Figure 4 is a schematic structural diagram of a first-type well region and a second-type well region formed on the epitaxial layer;

[0033] Figure 5 is a schematic structural diagram of an insulating reflective layer formed on the epitaxial layer;

[0034] Figure 6 is a schematic structural diagram of the insulating reflective layer after opening holes provided by an embodiment of the present application;

[0035] Figure 7 is a schematic structural diagram of a first electrode and a second electrode formed on the epitaxial layer;

[0036] Figure 8 for Figure 7 Side view of

[0037] Figure 9 It is a schematic diagram of the structure after the LED chip is connected to the adhesive layer of the temporary substrate;

[0038] Figure 10 It is a schematic diagram of the structure of separating the substrate and the LED chip;

[0039] Figure 11 A flow chart of a method for transferring an LED chip provided in another embodiment of the present application;

[0040] Figure 12 This is a schematic diagram of the structure after removing the glue layer around the LED chip;

[0041] Figure 13 A schematic diagram of the structure for removing the glue layer on the side of the insulating reflective layer away from the epitaxial layer;

[0042] Figure 14 This is a schematic diagram of the structure of an LED chip provided in one embodiment of the present application.

[0043] Description of Reference Numerals

[0044] LED chip 10; substrate 11, temporary substrate 12; substrate 121; glue layer 122; glue column 123; epitaxial layer 13; first type well region 131; second type well region 132; insulating reflective layer 14; through hole 141; first electrode 15; second electrode 16. DETAILED DESCRIPTION

[0045] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0046] The terms "first", "second", and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", and "third" may explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined. All directional indications (such as up, down, left, right, front, back...) in the embodiments of this application are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the drawings). If the specific posture changes, then the directional indications will also change accordingly. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices.

[0047] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0048] The present application will be described in detail below with reference to the drawings and embodiments.

[0049] Please refer to Figure 1a , Figure 1a which is a flowchart of a method for transferring an LED chip provided in an embodiment of this application; in this embodiment, a method for transferring an LED chip 10 is provided, where the LED chip 10 can be a Micro LED chip, and a display screen including the LED chip 10 can be used in display devices such as mobile phones and computers. The method for transferring the LED chip 10 includes:

[0050] Step S1: Provide a substrate and a temporary substrate.

[0051] Among them, referring to Figure 1b , Figure 1b which is a schematic structural diagram of a substrate provided in an embodiment of this application; the substrate 11 can be a 4- or 6-inch sapphire wafer. Referring to Figure 1c , Figure 1cSchematic structural diagram of a temporary substrate provided by an embodiment of the present application; the temporary substrate 12 includes a substrate 121 and an adhesive layer 122 disposed on the substrate 121; wherein, the substrate 121 may be a glass substrate; in a specific implementation manner, the adhesive layer 122 may be silicone coated on the substrate 121; of course, the adhesive layer 122 may also be an etchable tape adhered to the substrate 121. Wherein, the thickness of the adhesive layer 122 may be 8-12 microns; so that at least part of the structure of the subsequent LED chip 10 can be embedded in the adhesive layer 122, ensuring that the adhesive layer 122 can wrap at least part of the structure of the LED chip 10. Specifically, the thickness of the adhesive layer 122 may be 10 microns.

[0052] Step S2: Fabricate an LED chip on a substrate.

[0053] Refer to Figure 2 , Figure 2 is Figure 1a a sub-flowchart of step S2 in

[0054] Step S21: Form an epitaxial layer on a substrate.

[0055] In a specific implementation process, refer to Figure 3 and Figure 4 ; wherein, Figure 3 is a schematic structural diagram of forming an epitaxial layer on a substrate; Figure 4 is a schematic structural diagram of forming a first-type well region and a second-type well region on an epitaxial layer. Step S21 specifically includes: refer to Figure 3 , first grow a nucleation layer, a buffer layer, an N-semiconductor layer, a multi-quantum well layer, and a P-semiconductor layer on the substrate 11 in sequence to form an epitaxial layer 13. Among them, the nucleation layer is the aggregation of molecules into nuclei and outward growth during epitaxial growth, and it may specifically be an ALN layer; the buffer layer may specifically be a GaN layer or an AlGaInP layer; the N-semiconductor layer may specifically be an N-GaN layer; the multi-quantum well layer may specifically be an InGaN layer or a GaN layer; the P-semiconductor layer may specifically be a P-GaN layer. Then refer to Figure 4 , process the surface of the epitaxial layer 13 facing away from the substrate 11 to form a first-type well region 131 and a second-type well region 132. Specifically, the epitaxial layer 13 may be subjected to Mesa step etching and ISO etching to form an N-type semiconductor mesa. It can be understood that the epitaxial layer 13 has a first-type well region 131 and a second-type well region 132, wherein, the first-type well region 131 may be a p-type well region (p-well) for forming a P electrode; the second-type well region 132 may be an n-type well region (n-well) for forming an N electrode.

[0056] Step S22: Form an insulating reflective layer on the surface of the epitaxial layer facing away from the substrate, and open holes in the insulating reflective layer to expose at least the first-type well region and the second-type well region of the epitaxial layer.

[0057] In a specific embodiment, refer to Figure 5 , Figure 5 which is a schematic structural diagram of forming an insulating reflective layer on the epitaxial layer; an insulating reflective layer 14 can be deposited on the surface of the epitaxial layer 13 facing away from the substrate 11; then refer to Figure 6 , Figure 6 which is a schematic structural diagram of the insulating reflective layer after opening holes provided by an embodiment of the present application; open a hole in the middle position of the insulating reflective layer 14 to expose the first-type well region 131 and the second-type well region 132 of the epitaxial layer 13. Specifically, the insulating reflective layer 14 can form a communication hole.

[0058] Step S23: Form a first electrode and a second electrode in the first-type well region and the second-type well region of the epitaxial layer respectively to obtain an LED chip.

[0059] Among them, refer to Figure 7 and Figure 8 , Figure 7 which is a schematic structural diagram after forming the first electrode and the second electrode on the epitaxial layer; Figure 8 is Figure 7 a side view of. The first electrode 15 and the second electrode 16 can be formed on the first-type well region 131 and the second-type well region 132 of the epitaxial layer 13 by electron beam evaporation, and make parts of the first electrode 15 and the second electrode 16 protrude from the insulating reflective layer 14 to obtain the LED chip 10. Among them, the first electrode 15 and the second electrode 16 are located on the side of the LED chip 10 facing away from the substrate 11. The first electrode 15 can be a P electrode; the second electrode 16 can be an N electrode. Of course, the heights of the first electrode 15 and the second electrode 16 can also be lower than the depth of the holes opened in the insulating reflective layer 14, and the present application does not limit this, and can be specifically selected according to actual needs.

[0060] In a specific embodiment, the side walls of the first electrode 15 and the second electrode 16 are attached to the side walls of the holes opened in the insulating reflective layer 14 to avoid forming a gap between the insulating reflective layer 14 and the first electrode 15 and / or the second electrode 16, thereby avoiding the subsequent adhesive layer 122 from entering the gap between the two, making it easier to etch the adhesive layer 122 around the LED chip.

[0061] Specifically, in this embodiment, before forming the first electrode 15 and the second electrode 16, the insulating reflection layer 14 is enclosed to form a communication hole. After forming the first electrode 15 and the second electrode 16, part of the region of the first type well region 131 and / or part of the region of the second type well region 132 are exposed through the opening. Specifically, the region of the first type well region 131 except for the region where the first electrode 15 is disposed and the region of the second type well region 132 except for the region where the second electrode 16 is disposed are exposed through the opening, and the exposed region is located between the first electrode 15 and the second electrode 16. In this embodiment, the first electrode 15, the second electrode 16, the insulating reflection layer 14, the first type well region 131 and the second type well region 132 define and form a through hole 141; wherein, the first electrode 15, the second electrode 16 and the insulating reflection layer 14 enclose and form the side wall of the through hole 141, and the first type well region 131 and the second type well region 132 form the bottom wall of the through hole 141.

[0062] When performing step S3, part of the glue layer 122 is filled into the through hole 141 to form a glue column 123, which can not only further fix the position of the LED chip 10, prevent the LED chip 10 from deflecting during the peeling process from the substrate 11, but also ensure that the shape regularity of the glue column 123 left after performing step S5 subsequently is consistent, so as to facilitate the picking up of the LED chip 10.

[0063] In a specific embodiment, the above-mentioned insulating reflection layer 14 may be a distributed Bragg reflection (DBR) reflection layer. Those skilled in the art can understand that in the prior art, the size of the Micro LED chip 10 is small, and it is difficult to use a DBR reflection layer with a large thickness to improve the light effect. However, in the embodiment of the present application, the DBR reflection layer is used to replace the ordinary insulating layer, and part of the first electrode 15 and the second electrode 16 of the LED chip 10 are buried into the opening structure of the DBR reflection layer, making it possible for the Micro LED chip 10 to use the inorganic DBR reflection layer to improve the light effect.

[0064] Step S3: Connect the surface of the LED chip facing away from the substrate to the glue layer of the temporary substrate, and embed at least part of the structure of the LED chip in the glue layer.

[0065] Specifically, refer to Figure 9 , Figure 9The figure is a schematic structural diagram after the bonding layer connection between the LED chip and the temporary substrate. The surface of one side of the LED chip 10 facing away from the substrate 11 can be bonded to the bonding layer 122 of the temporary substrate 12, and at least part of the structure of the insulating reflective layer 14 is embedded in the bonding layer 122; that is, the bonding layer 122 wraps at least part of the structure of the insulating reflective layer 14 of the LED chip 10. This not only effectively improves the connection strength between the LED chip 10 and the temporary substrate 12, but also can protect the LED chip 10 through the bonding layer 122 and fix the position of the LED chip 10, so as to avoid the problems of fracture or deflection of the LED chip 10 during the subsequent peeling process of the substrate 11 and the LED chip 10, thereby effectively improving the peeling yield of the LED chip 10.

[0066] Step S4: Separate the substrate from the LED chip.

[0067] See Figure 10 , Figure 10 The figure is a schematic structural diagram of the separation between the substrate and the LED chip. Specifically, the substrate 11 can be removed by laser.

[0068] The transfer method of the LED chip 10 provided in this embodiment includes providing a substrate 11 and a temporary substrate 12, then fabricating the LED chip 10 on the substrate 11; then connecting the surface of one side of the LED chip 10 facing away from the substrate 11 to the bonding layer 122 of the temporary substrate 12, and embedding at least part of the structure of the LED chip 10 in the bonding layer 122; finally separating the substrate 11 from the LED chip 10. Among them, since at least part of the structure of the LED chip 10 is embedded in the bonding layer 122, that is, the bonding layer 122 wraps at least part of the structure of the LED chip 10, this not only effectively improves the connection strength between the LED chip 10 and the temporary substrate 12, but also can protect the LED chip 10 through the bonding layer 122 and fix the position of the LED chip 10, so as to avoid the problems of fracture or deflection of the LED chip 10 during the subsequent peeling process of the substrate 11 and the LED chip 10, thereby effectively improving the peeling yield of the LED chip 10. At the same time, by making the insulating reflective layer 14 a DBR reflective layer, replacing the ordinary insulating layer in the existing solution with the DBR reflective layer, and the design of burying part of the structures of the first electrode 15 and the second electrode 16 of the LED chip 10 into the opening structure of the DBR reflective layer, it becomes possible to improve the light efficiency of the LED chip 10 by using the inorganic DBR reflective layer.

[0069] Please refer to Figure 11 , Figure 11 The figure is a flowchart of the transfer method of the LED chip provided in another embodiment of the present application; in one embodiment, further after step S4, it includes:

[0070] Step S5 includes: removing the glue layer wrapping the LED chip, and spacing the insulating reflective layer of the LED chip from the glue layer.

[0071] In this embodiment, step S5 specifically includes:

[0072] Step S51: removing the glue layer around the LED chip along the first direction by using a collimated etching method until the entire LED chip is exposed.

[0073] The first direction is parallel to the stacking direction of the substrate 11 and the epitaxial layer 13. Figure 12 , Figure 12 The schematic diagram is a structural diagram after removing the glue layer 122 around the LED chip 10. The glue layer 122 around the LED chip 10 can be etched in a dry collimated manner, which has a fast etching rate and can ensure that the colloid under the LED chip 10 exists and has a regular and uniform structure.

[0074] Step S52 : removing the glue layer 122 on the side of the insulating reflective layer 14 away from the epitaxial layer 13 by isotropic etching along the second direction, so that the insulating reflective layer 14 is spaced apart from the glue layer 122 .

[0075] The first direction and the second direction are perpendicular. Figure 13 , Figure 13 The schematic diagram is a structural diagram of removing the adhesive layer on the side of the insulating reflective layer away from the epitaxial layer. By spacing the insulating reflective layer 14 and the adhesive layer 122, the connection strength between the LED chip 10 and the adhesive layer 122 can be reduced, which facilitates the subsequent picking of the LED chip 10, thereby improving the picking yield of the LED chip 10.

[0076] Among them, on the basis of step S51, the colloid under the LED chip 10 is further etched isotropically, which can further make the size and shape consistency of the glue column 123 remaining in the opening of the epitaxial layer 13 better than the scheme of etching in an anisotropic manner. At the same time, compared with the scheme of using a single-step etching process to weaken the structure of the LED chip 10 in the prior art, the embodiment of the present application adopts a combination of collimated etching and isotropic etching to weaken the adhesion of the LED chip 10 to the glue layer 122 on the temporary substrate 12, and combined with the special structure of the LED chip 10, the shape and size of the glue column 123 under the LED chip 10 after etching are more uniform; and the effect has been proven in practice, and the above scheme of the present application greatly improves the pickup yield of the LED chip 10; and the process is simple, more feasible for mass production, effectively reduces the difficulty of mass transfer, and further improves the transfer yield of the LED chip 10.

[0077] In one embodiment, see Figure 14, Figure 14 The structural schematic diagram of the LED chip provided by an embodiment of the present application. The present application provides an LED chip 10, and the LED chip 10 can be obtained by the method for preparing the LED chip 10 described above. The LED chip 10 includes an epitaxial layer 13, an insulating reflective layer 14, a first electrode 15, and a second electrode 16. Optionally, the LED chip 10 can be a Micro LED chip.

[0078] Among them, the epitaxial layer 13 includes a nucleation layer, a buffer layer, an N-semiconductor layer, a multi-quantum well layer, and a P-semiconductor layer which are stacked. Among them, the nucleation layer is formed by molecules aggregating into nuclei and growing outwards during the epitaxial growth process, and it can specifically be an ALN layer; the buffer layer can specifically be a GaN layer or an AlGaInP layer; the N-semiconductor layer can specifically be an N-GaN layer; the multi-quantum well layer can specifically be an InGaN layer or a GaN layer; the P-semiconductor layer can specifically be a P-GaN layer. Specifically, the epitaxial layer 13 has a first-type well region 131 and a second-type well region 132. Among them, the first-type well region 131 can be a p-type well region (p-well) for forming a P electrode; the second-type well region 132 can be an n-type well region (n-well) for forming an N electrode.

[0079] The insulating reflective layer 14 is disposed on the surface of the P-GaN layer facing away from the multi-quantum well layer, and is disposed around the first-type well region 131 and the second-type well region 132, and a communication hole is formed within the surrounding area of the insulating reflective layer 14. Specifically, the insulating reflective layer 14 can be a DBR reflective layer, which greatly improves the light efficiency of the LED chip 10.

[0080] The first electrode 15 is embedded in the communication hole and is located in the first-type well region 131 of the epitaxial layer 13; the second electrode 16 is embedded in the communication hole and is located in the second-type well region 132 of the epitaxial layer 13. Specifically, the first electrode 15 and / or the second electrode 16 can protrude out of the communication hole, or be entirely located within the communication hole. Among them, the first electrode 15 is a P electrode; the second electrode 16 is an N electrode. In a specific embodiment, the P-GaN layer of the epitaxial layer 13 between the first electrode 15 and the second electrode 16 is exposed through the communication hole. Specifically, in this embodiment, the space formed by enclosing the first electrode 15, the second electrode 16, the insulating reflective layer 14, and the epitaxial layer 13 is the through hole 141, that is, in this embodiment, the through hole is the hole region in the communication hole after the first electrode 15 and the second electrode 16 are disposed.

[0081] Specifically, the side walls of the first electrode 15 and the second electrode 16 are attached to the side walls of the openings of the insulating reflective layer 14 to avoid forming a gap between the insulating reflective layer 14 and the first electrode 15 and / or the second electrode 16, thereby preventing the subsequent adhesive layer 122 from entering the gap therebetween and making it easier to etch the adhesive layer 122 around the LED chip.

[0082] For the LED chip 10 provided in this embodiment, by providing the epitaxial layer 13 and making the epitaxial layer 13 have the first-type well region 131 and the second-type well region 132, the first electrode 15 and the second electrode 16 are respectively formed in the first-type well region 131 and the second-type well region 132. At the same time, by providing the insulating reflective layer 14 and disposing the insulating reflective layer 14 on the surface of the epitaxial layer 13 having the first-type well region 131 and the second-type well region 132 and surrounding the first-type well region 131 and the second-type well region 132, the first electrode 15 and the second electrode 16 formed in the first-type well region 131 and the second-type well region 132 can be protected and positioned. In addition, by making the enclosed area of the insulating reflective layer 14 a communication hole and embedding the first electrode 15 and the second electrode 16 in the communication hole, it becomes possible for the LED chip 10 to use an inorganic DBR reflective layer; and by making the insulating reflective layer 14 a DBR reflective layer, the light efficiency of the LED chip 10 can be greatly improved.

[0083] The above are only the embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied to other related technical fields, shall be equally included in the patent protection scope of the present application.

Claims

1. A method for transferring an LED chip, characterized in that, it includes: providing a substrate and a temporary substrate; wherein, an adhesive layer is formed on the temporary substrate; fabricating an LED chip on the substrate; connecting a surface of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate, and embedding at least part of the structure of the LED chip in the adhesive layer; separating the substrate from the LED chip; The step of fabricating the LED chip on the substrate specifically includes: forming an epitaxial layer on the substrate; wherein, the epitaxial layer has a first-type well region and a second-type well region; forming an insulating reflective layer on a surface of the epitaxial layer facing away from the substrate, and opening holes in the insulating reflective layer to expose at least the first-type well region and the second-type well region of the epitaxial layer; forming a first electrode and a second electrode in the first-type well region and the second-type well region of the epitaxial layer respectively to fabricate an LED chip; after forming the first electrode and the second electrode in the first-type well region and the second-type well region of the epitaxial layer respectively, part of the region of the first-type well region and / or part of the region of the second-type well region are exposed through the opening holes; The step of connecting a surface of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate, and embedding at least part of the structure of the LED chip in the adhesive layer specifically includes: connecting a surface of the LED chip facing away from the substrate to the adhesive layer of the temporary substrate, and embedding at least part of the structure of the insulating reflective layer in the adhesive layer, and the adhesive layer fills the opening holes.

2. The method for transferring an LED chip according to claim 1, characterized in that, after the step of separating the substrate from the LED chip, it further includes: removing the adhesive layer wrapping the LED chip, and spacing the insulating reflective layer of the LED chip from the adhesive layer.

3. The method for transferring an LED chip according to claim 2, characterized in that, The step of removing the adhesive layer wrapping the LED chip, and spacing the insulating reflective layer of the LED chip from the adhesive layer specifically includes: removing the adhesive layer around the LED chip along a first direction by using a collimated etching method until the entire LED chip is exposed; removing the adhesive layer on a side of the insulating reflective layer facing away from the epitaxial layer along a second direction by using an isotropic etching method to space the insulating reflective layer from the adhesive layer; wherein, the first direction and the second direction are perpendicular.

4. The method for transferring an LED chip according to claim 2, characterized in that, the insulating reflective layer is a DBR reflective layer.

5. The method for transferring an LED chip according to claim 1, characterized in that, The step of forming the epitaxial layer on the substrate specifically includes: successively growing a nucleation layer, a buffer layer, an N-semiconductor layer, a multi-quantum well layer, and a P-semiconductor layer on the substrate to form an epitaxial layer; processing a surface of the epitaxial layer facing away from the substrate to form a first-type well region and a second-type well region.

6. An LED chip, characterized in that, the LED chip is prepared by using the transfer method of the LED chip according to any one of claims 1-5; the LED chip comprises: an epitaxial layer having a first-type well region and a second-type well region; an insulating reflective layer disposed on the surface of the epitaxial layer having the first-type well region and the second-type well region and surrounding the first-type well region and the second-type well region, and a communication hole is provided within the surrounding area of the insulating reflective layer; a first electrode embedded in the communication hole and located in the first-type well region; a second electrode embedded in the communication hole and located in the second-type well region.

7. The LED chip according to claim 6, characterized in that, the insulating reflective layer is a DBR reflective layer.

8. The LED chip according to claim 6, characterized in that, the first electrode and / or the second electrode is disposed in contact with the insulating reflective layer.

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