Three-primary-color Micro-LED chip and preparation and giant conversion method thereof

Abstract

The invention discloses an RGB three-primary-color Micro-LED chip and a preparation and giant conversion method thereof, and relates to the technical field of semiconductor devices.The method comprises the steps that chip manufacturing is conducted on a pre-provided target wafer, an RGB three-primary-color Micro chip with a common cathode and an independent anode is obtained, and when formal giant transfer is conducted, only one-time laser giant transfer is needed, and therefore the requirement for large-scale transfer of the RGB three-primary-color Micro-LED chip is met, and the requirement for large-scale transfer of the RGB three-primary-color Micro-LED chip is met. According to the technical scheme, the RGB three-primary-color Micro chip can be transferred to the circuit substrate by arranging the cathode electrode and the anode electrode of the RGB three-primary-color Micro chip, and meanwhile, because the cathode electrode of the RGB three-primary-color Micro chip is in a common cathode design, the die bonding and bonding effects of the RGB three-primary-color Micro chip and the circuit substrate are increased, and the bonding of the RGB three-primary-color Micro chip and the circuit substrate is more stable. By adopting the method disclosed by the invention, the transfer efficiency of the RGB three-primary-color Micro chip can be effectively improved, the manufacturing cost is reduced, and the bonding stability can be improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor device technology, and in particular to an RGB three-primary color Micro-LED chip and a preparation and giant conversion method thereof. Background Art

[0002] Micro LED micro-display technology has the characteristics of self-luminescence. Each pixel can be driven to emit light independently. Its advantages include high brightness, low power consumption, small size, ultra-high resolution and color saturation. Compared with OLED, which is also a self-luminous display, Micro LED is not only more efficient and has a longer lifespan, but the material is not easily affected by the environment and is relatively stable, which can effectively avoid the phenomenon of afterimage.

[0003] At present, the common technology of Micro LED display is to use a set of light-emitting units composed of RGB three-primary color wafer chips, peel off the substrate materials of the RGB three-primary color wafers separately, and then transfer them to the target substrate through giant transfer (i.e. mass transfer).

[0004] In the above-mentioned traditional technologies, the wafers are all monochrome wafers, and the substrates of the three-primary-color wafers need to be peeled off, that is, they need to be peeled off three times, and the mass transfer also needs to be transferred three times accordingly, which greatly increases the production cost of the RGB three-primary-color Micro-LED chips. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an RGB three-primary color Micro-LED chip and a preparation and mass transfer method thereof, aiming to reduce the production cost of RGB three-primary color Micro-LED chips by optimizing the mass transfer method of RGB three-primary color Micro-LED chips.

[0006] The first aspect of the present invention is to provide a method for preparing and converting a RGB three-primary color Micro LED chip, the method comprising: Providing a target wafer, the target wafer comprising a substrate and a first epitaxial layer, a second epitaxial layer and a third epitaxial layer spaced apart from each other on the substrate; Making a passivation layer on one side of the first epitaxial layer, the second epitaxial layer and the third epitaxial layer in the target wafer, so that the passivation layer covers the first epitaxial layer, the second epitaxial layer and the third epitaxial layer; Performing photolithography on the passivation layer to expose the first epitaxial layer, the second epitaxial layer and the third epitaxial layer respectively, and manufacturing a first N electrode and a first P electrode respectively contacting the N-type semiconductor layer and the P-type semiconductor layer in the first epitaxial layer, the second epitaxial layer and the third epitaxial layer; A reflective layer is coated on the surface of the target wafer, and the reflective layer is photoetched to expose the first N electrode and the first P electrode, and a second N electrode connected to the first N electrode and a second P electrode connected to the first P electrode are manufactured; Bonding the second N electrode and the second P electrode to a preset first temporary substrate through a first bonding layer, and removing the substrate in the target wafer; Fabricating a reinforcement layer on a surface of the first epitaxial layer, the second epitaxial layer, and the third epitaxial layer in the target wafer away from the second N-electrode and the second P-electrode; Bonding the reinforcement layer to a preset second temporary substrate via a second adhesive layer, and removing the first temporary substrate; Mass transfer is performed through the second temporary substrate, and the semi-finished chip is aligned with the circuit substrate so that the cathode area of ​​the circuit substrate corresponds to the second N electrode connected with a common cathode, and the anode area of ​​the circuit substrate corresponds to the second P electrode respectively, and the chip and the circuit substrate are connected through a bonding process.

[0007] According to one aspect of the above technical solution, the first epitaxial layer, the second epitaxial layer and the third epitaxial layer are a blue epitaxial layer, a green epitaxial layer and a red epitaxial layer respectively.

[0008] According to one aspect of the above technical solution, the structures and materials of the first N electrode and the first P electrode on the first epitaxial layer and the second epitaxial layer are the same, and the third epitaxial layer is different. The thicknesses of the first N electrode and the first P electrode on the first epitaxial layer, the second epitaxial layer and the third epitaxial layer are equal.

[0009] According to one aspect of the above technical solution, the thickness of the first N electrode and the first P electrode on the first epitaxial layer, the second epitaxial layer and the third epitaxial layer are all 30nm-1000nm.

[0010] According to one aspect of the above technical solution, the first N-electrode on the first epitaxial layer and the first N-electrode on the second epitaxial layer both include an ohmic contact layer, a reflective layer, a cladding layer, an etching stop layer and an adhesion layer which are stacked; The first N-electrode on the third epitaxial layer includes an adhesion layer, an ohmic layer, a cladding layer, an etching stop layer and an adhesion layer which are stacked.

[0011] According to one aspect of the above technical solution, the second N electrode and the second P electrode are bonded to a preset first temporary substrate through a first bonding layer, and in the step of removing the substrate in the target wafer, the step of removing the substrate in the target wafer includes: Using a pre-configured etching solution to corrode the substrate in the target wafer to remove the substrate; The corrosion solution is a solution of NH4OH:H2O2 in a ratio of 1:9, and the corrosion time is 20 min-60 min.

[0012] According to one aspect of the above technical solution, the second temporary substrate is made of a transparent material, and the second adhesive layer is made of a UV photosensitive material.

[0013] According to one aspect of the above technical solution, the second temporary substrate is glass or sapphire.

[0014] The second aspect of the present invention is to provide an RGB three-primary color Micro LED chip, and the RGB three-primary color Micro LED chip is prepared by the method described in the above technical solution.

[0015] A third aspect of the present invention provides a circuit substrate for connecting to an RGB three-primary color Micro LED chip in the method described in the above technical solution.

[0016] Compared with the prior art, the RGB three-primary color Micro-LED chip and its preparation and conversion method shown in the present invention have the following beneficial effects: The present invention obtains RGB three-primary color Micro chips with common cathode and independent anode by chip manufacturing on the pre-provided target wafer. When performing formal mass transfer, only one laser mass transfer is required to realize the transfer of the RGB three-primary color Micro chip to the circuit substrate. At the same time, since the cathode electrode of the RGB three-primary color Micro chip is a common cathode design, the solid crystal bonding effect between the RGB three-primary color Micro chip and the circuit substrate is increased, making the bonding between the RGB three-primary color Micro chip and the circuit substrate more stable. The method shown in the present invention can effectively improve the transfer efficiency of the RGB three-primary color Micro chip during mass transfer, reduce the production cost of the RGB three-primary color Micro chip, and improve the bonding stability of the RGB three-primary color Micro chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a schematic structural diagram of a target wafer shown in one embodiment of the present invention; Figure 2 It is a schematic diagram of the structure of manufacturing a passivation layer on a target wafer in one embodiment of the present invention; Figure 3 It is a structural schematic diagram of manufacturing a first P electrode on a target wafer in one embodiment of the present invention; Figure 4It is a schematic diagram of a structure in which a reflective layer is fabricated on a passivation layer in one embodiment of the present invention; Figure 5 It is a schematic structural diagram of manufacturing a second N electrode connected to the first N electrode on the reflective layer in one embodiment of the present invention; Figure 6 It is a schematic structural diagram of manufacturing a second P electrode connected to the first P electrode on the reflective layer in one embodiment of the present invention; Figure 7 It is a structural schematic diagram of manufacturing a first temporary substrate on an electrode surface in one embodiment of the present invention; Figure 8 It is a structural schematic diagram of removing the substrate after fixing the first temporary substrate in one embodiment of the present invention; Fig. 9 It is a schematic diagram of a structure in which a reinforcement layer is fabricated on a substrate in one embodiment of the present invention; Fig.10 It is a structural schematic diagram of manufacturing a second temporary substrate on a reinforcement layer in one embodiment of the present invention; Fig.11 It is a schematic structural diagram of a circuit substrate in one embodiment of the present invention; Component symbol description: Substrate 10, buffer layer 11, first epitaxial layer 21, second epitaxial layer 22, third epitaxial layer 23, passivation layer 30, passivation layer through hole 31, first P electrode 42, second N electrode 43, second P electrode 44, reflective layer 50, first temporary substrate 60, first adhesive layer 61, reinforcement layer 70, second temporary substrate 80, second adhesive layer 81, cathode region 91, anode region 92. DETAILED DESCRIPTION

[0018] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. Several embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0019] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0021] First embodiment See also Figures 1 to 11 The first embodiment of the present invention provides a method for preparing and mass transferring an RGB three-primary color Micro LED chip, which is used for chip manufacturing and mass transfer of an RGB three-primary color Micro LED epitaxial wafer. The method includes steps S10 to S80: In step S10 , a target wafer is provided. The target wafer includes a substrate and a first epitaxial layer, a second epitaxial layer, and a third epitaxial layer spaced apart from each other on the substrate.

[0022] It should be noted that the target wafer in step S10 of this embodiment, i.e., the above-mentioned RGB three-primary color Micro LED epitaxial wafer, is Figure 1 As shown, it includes a substrate 10 and an epitaxial layer disposed on the substrate 10, wherein the substrate 10 may be a GaAs substrate, i.e., a gallium arsenide substrate; and the epitaxial layer disposed on the substrate 10 includes a first epitaxial layer 21, a second epitaxial layer 22, and a third epitaxial layer 23, and the first epitaxial layer 21, the second epitaxial layer 22, and the third epitaxial layer 23 are arranged at intervals on the substrate 10, rather than being vertically stacked. The substrate 10 may have a plurality of chip units, each of which includes a first epitaxial layer 21, a second epitaxial layer 22, and a third epitaxial layer 23 arranged at intervals.

[0023] Among them, the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23 are respectively located at the first position, the second position and the third position on the substrate 10, adjacent to each other and arranged at intervals, and the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23 are specifically a blue epitaxial layer, a green epitaxial layer and a red epitaxial layer, that is, in a single chip unit, the second epitaxial layer 22 as the green epitaxial layer is located between the first epitaxial layer 21 and the third epitaxial layer 23. For the convenience of description, in this embodiment, the blue epitaxial layer, the green epitaxial layer and the red epitaxial layer will continue to be described in the form of the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23.

[0024] In addition, as a preference, in this embodiment, a buffer layer 11 may be further provided on the substrate 10. Specifically, the first epitaxial layer 21 and the second epitaxial layer 22 are provided on the buffer layer 11, and the third epitaxial layer 23 is directly provided on the substrate 10, and the heights of the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23 are kept consistent, that is, the sum of the thicknesses of the first epitaxial layer 21 or the second epitaxial layer 22 and the buffer layer 11 is equal to the thickness of the third epitaxial layer 23.

[0025] Step S20 , forming a passivation layer on one side of the first epitaxial layer, the second epitaxial layer and the third epitaxial layer in the target wafer, so that the passivation layer covers the first epitaxial layer, the second epitaxial layer and the third epitaxial layer.

[0026] In this embodiment, Figure 2 As shown, after providing a target wafer, a passivation layer 30 is firstly formed on the substrate 10 , so that the passivation layer 30 covers the first epitaxial layer 21 , the second epitaxial layer 22 , the third epitaxial layer 23 and the exposed surface of the substrate 10 .

[0027] Specifically, a passivation layer 30 is deposited on the substrate 10 by using an ALD device. The material may be SiO2 or Al2O3, preferably SiO2, and the thickness thereof is 30nm-500nm.

[0028] In step S30, the passivation layer is photolithographically processed to expose the first epitaxial layer, the second epitaxial layer and the third epitaxial layer respectively, and a first N electrode and a first P electrode are fabricated to contact the N-type semiconductor layer and the P-type semiconductor layer in the first epitaxial layer, the second epitaxial layer and the third epitaxial layer respectively.

[0029] In this embodiment, after the passivation layer 30 is deposited by the ALD device, a hole is opened on the passivation layer 30 by wet etching to obtain a passivation layer through hole 31, exposing the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23 at the bottom. Then, as Figure 3 As shown, electrodes are fabricated in the passivation layer through hole 31 to obtain a first N electrode and a first P electrode 42 that are in contact with the N-type semiconductor layer and the P-type semiconductor layer in the first epitaxial layer 21 , the second epitaxial layer 22 , and the third epitaxial layer 23 , respectively.

[0030] It should be noted that the existing process generally involves making electrodes first and then making the passivation layer 30. In this embodiment, the process steps are replaced because the Micro chip is relatively small. By first preparing the passivation layer 30, wrapping the epitaxial layer with the passivation layer 30, and then using the coating method to make the electrode, leakage will not occur due to metal coating on the side wall of the epitaxial layer.

[0031] The structures and materials of the first N-electrode and the first P-electrode 42 on the first epitaxial layer 21 and the second epitaxial layer 22 are the same, while the third epitaxial layer 23 is different, that is, the structures and materials of the third epitaxial layer 23 and the first N-electrode and the first P-electrode 42 on the first epitaxial layer 21 and the second epitaxial layer 22 are different. However, the thicknesses of the first N-electrode and the first P-electrode 42 on the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23 are equal.

[0032] Specifically, the structure, material and thickness of the first N electrode on the first epitaxial layer 21 and the second epitaxial layer 22 are the same, and the structure, material and thickness of the first P electrode 42 on the first epitaxial layer 21 and the second epitaxial layer 22 are equal. The first N electrode and the first P electrode 42 have different thicknesses because the semiconductor layers they are connected to are N-type semiconductor layers and P-type semiconductor layers, respectively, but their structures and materials are the same. The first N electrode and the first P electrode 42 on the third epitaxial layer 23 are different from the first N electrode and the first P electrode 42 on the first epitaxial layer 21 and the second epitaxial layer 22.

[0033] In this embodiment, the first N electrode and the first P electrode 42 on the first epitaxial layer 21 and the second epitaxial layer 22 have structures of an ohmic contact layer, an electrode reflective layer, a coating layer, an etching barrier layer and an adhesion layer from bottom to top. The ohmic contact layer material is one of Cr, Ti or Ni, with a thickness of 10Å-100Å, the electrode reflective layer material is Al, with a thickness of 500Å-3000Å, the coating layer material is a stacked structure formed by Ti or Ni and Pt, the etching barrier layer material is Pt or Au, with a thickness of 2000Å-5000Å, and the adhesion layer material is Ti, with a thickness of 25Å-70Å.

[0034] Different from this, the first N electrode and the first P electrode 42 on the third epitaxial layer 23 have a structure of an attachment layer, an ohmic contact layer, a coating layer, an etch barrier layer and an adhesion layer from bottom to top. The attachment layer material is Au with a thickness of 50Å-500Å, the ohmic contact layer material is AuGeNi alloy with a thickness of 500Å-3000Å, the coating layer material is a stacked structure formed by Ti or Ni and Pt, the etching barrier layer material is Pt or Au with a thickness of 2000Å-5000Å, and the adhesion layer material is Ti with a thickness of 25Å-70Å.

[0035] As described above, the thickness of the first N-electrode and the first P-electrode 42 on the first epitaxial layer 21 and the second epitaxial layer 22 , or the first N-electrode and the first P-electrode 42 on the third epitaxial layer 23 is within the range of 30 nm to 1000 nm.

[0036] Step S40, coating a reflective layer on the surface of the target wafer, and photolithography the reflective layer to expose the first N electrode and the first P electrode, and fabricating a second N electrode connected to the first N electrode and a second P electrode connected to the first P electrode.

[0037] In this embodiment, if Figure 4 As shown, after the first N electrode and the first P electrode 42 are produced, a reflective layer 50 is coated on the surface of the target wafer, specifically a DBR reflective layer composed of alternating SiO2 / Ti2O5 materials, and then the reflective layer 50 is photolithographically processed to obtain a reflective layer through hole, exposing the first N electrode and the first P electrode 42 corresponding to the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23, respectively.

[0038] The thickness of the reflective layer 50 on the first epitaxial layer 21 , the second epitaxial layer 22 and the third epitaxial layer 23 is consistent.

[0039] Furthermore, after the reflective layer 50 is photolithographically exposed to expose the first N electrode and the first P electrode 42 corresponding to the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23, respectively, a metal plating process is further used to form a second N electrode 43 connected to a common cathode on the first N electrode, such as Figure 5 As shown, a correspondingly connected second P electrode 44 is fabricated on the first P electrode 42, as shown Figure 6 shown.

[0040] It is easy to understand that in a single chip unit, there are three first N electrodes on the first epitaxial layer 21, the second epitaxial layer 22 and the third epitaxial layer 23, and there is only one second N electrode 43 manufactured later, so as to connect the three first N electrodes together in a cathode manner. The second P electrode 44 is connected to the first P electrode 42 in correspondence, that is, there are three first P electrodes 42 and three second P electrodes 44 as well.

[0041] That is, in each chip unit, the anode (P electrode) is independent, while the cathode (N electrode) is a common cathode, and is connected together to the negative electrode. At the same time, because the Micro chip is relatively small, the second N electrode 43 is used to connect the first N electrode together to increase the eutectic bonding force with the circuit substrate, making the chip and the circuit substrate more stably bonded.

[0042] The above steps are all steps for chip manufacturing. In this embodiment, the mass transfer of chips will be explained in detail, and some chip manufacturing steps are also mixed in this process to obtain the final chip, and the mass transfer of chips is performed based on this.

[0043] Step S50, bonding the second N-electrode and the second P-electrode to a preset first temporary substrate through a first bonding layer, and removing the substrate in the target wafer.

[0044] Specifically, if Figure 7 As shown, on the front side of the target wafer, that is, the electrode surface where the second N electrode 43 and the second P electrode 44 are located, the first temporary substrate 60 is bonded by the first bonding layer 61, so as to fix the chip. After the chip is fixed, as shown in FIG. Figure 8 As shown, a pre-configured etching solution is used to etch the substrate 10 in the target wafer to remove the substrate 10 . At this time, the entire chip will be supported by the first temporary substrate 60 .

[0045] The etching solution is a solution of NH4OH:H2O2 in a ratio of 1:9, and the etching time is 20 min-60 min, which can be adjusted according to the thickness of the substrate 10.

[0046] Step S60 , forming a reinforcement layer on a surface of the first epitaxial layer, the second epitaxial layer, and the third epitaxial layer in the target wafer that is away from the second N-electrode and the second P-electrode.

[0047] Specifically, if Fig. 9 As shown, a reinforcement layer 70 is made at the original position of the substrate 10 in the target wafer to increase the stability during mass transfer of chips, wherein the reinforcement layer 70 may be made of SiO2 or Al2O3 with a thickness of 0.5µm-20µm.

[0048] Step S70 , bonding the reinforcement layer to a preset second temporary substrate via a second adhesive layer, and removing the first temporary substrate.

[0049] Specifically, if Fig.10 As shown, after the reinforcement layer 70 is produced, a preset second temporary substrate 80 is bonded to the surface of the reinforcement layer 70 through the second adhesive layer 81, and the first temporary substrate 60 is removed after bonding and fixing. At this time, the entire chip is supported by the reinforcement layer 70 and the second temporary substrate 80.

[0050] The second temporary substrate 80 is made of a transparent material, such as glass or sapphire, and the second adhesive layer 81 is made of a UV photosensitive material.

[0051] Step S80, perform mass transfer through the second temporary substrate, align the semi-finished chip with the circuit substrate, make the cathode area of ​​the circuit substrate correspond to the second N electrode connected with the common cathode, and make the anode area of ​​the circuit substrate correspond to the second P electrode respectively, and connect the chip with the circuit substrate through a bonding process.

[0052] Specifically, the semi-finished chip prepared above is aligned with the pre-provided circuit substrate. In a single chip unit, Fig.11 As shown, three anode regions 92 preset on the circuit substrate correspond to three anode electrodes (ie, second P electrodes 44 ) of the chip respectively, and one cathode region 91 preset on the circuit substrate corresponds to one common cathode electrode (ie, second N electrode 43 ) of the chip.

[0053] By using the above-mentioned semi-finished chips and UV laser mass transfer equipment, only one laser mass transfer is needed to transfer the RGB three-primary color Micro chips to the circuit substrate at the same time, which is more efficient than the existing mass transfer method.

[0054] Then, through the bonding process, the RGB three-primary color Micro chip can be connected to the circuit substrate to obtain the corresponding chip module.

[0055] In summary, compared with the prior art, the method for preparing and converting the RGB three-primary color Micro LED chip shown in this embodiment has the following beneficial effects: This embodiment makes chips on the target wafer provided in advance to obtain RGB three-primary color Micro chips with common cathode and independent anode. When performing formal mass transfer, only one laser mass transfer is needed to transfer the RGB three-primary color Micro chips to the circuit substrate. At the same time, since the cathode electrode of the RGB three-primary color Micro chip is a common cathode design, the solid crystal bonding effect between the RGB three-primary color Micro chip and the circuit substrate is increased, making the bonding between the RGB three-primary color Micro chip and the circuit substrate more stable. The method shown in this embodiment can effectively improve the transfer efficiency of the RGB three-primary color Micro chip during mass transfer, reduce the production cost of the RGB three-primary color Micro chip, and improve the bonding stability of the RGB three-primary color Micro chip.

[0056] The present embodiment also provides an RGB three-primary color Micro LED chip, which is prepared by the method shown in the present embodiment. The chip as a whole includes a substrate 10 and a first epitaxial layer 21, a second epitaxial layer 22 and a third epitaxial layer 23 arranged at intervals on the substrate 10, and each epitaxial layer is provided with a first N electrode and a first P electrode 42, as well as a second N electrode 43 that connects the first N electrode to a common cathode, and a second P electrode 44 that is correspondingly connected to the first P electrode 42.

[0057] On the other hand, this embodiment further provides a circuit substrate for mass transfer in the method shown in this embodiment. The circuit substrate is provided with a common cathode region 91 and an independently arranged anode region 92, which are respectively used to connect with the common cathode electrode (second N electrode 43) and the anode electrode (second P electrode 44), thereby realizing the connection between the RGB three-primary color Micro LED chip and the circuit substrate.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0059] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing and converting a RGB three-primary color Micro LED chip, characterized in that: The method comprises: Providing a target wafer, the target wafer comprising a substrate and a first epitaxial layer, a second epitaxial layer and a third epitaxial layer spaced apart from each other on the substrate; Making a passivation layer on one side of the first epitaxial layer, the second epitaxial layer and the third epitaxial layer in the target wafer, so that the passivation layer covers the first epitaxial layer, the second epitaxial layer and the third epitaxial layer; Performing photolithography on the passivation layer to expose the first epitaxial layer, the second epitaxial layer and the third epitaxial layer respectively, and manufacturing a first N electrode and a first P electrode respectively contacting the N-type semiconductor layer and the P-type semiconductor layer in the first epitaxial layer, the second epitaxial layer and the third epitaxial layer; A reflective layer is coated on the surface of the target wafer, and the reflective layer is photoetched to expose the first N electrode and the first P electrode, and a second N electrode connected to the first N electrode and a second P electrode connected to the first P electrode are manufactured; Bonding the second N electrode and the second P electrode to a preset first temporary substrate through a first bonding layer, and removing the substrate in the target wafer; Fabricating a reinforcement layer on a surface of the first epitaxial layer, the second epitaxial layer, and the third epitaxial layer in the target wafer away from the second N-electrode and the second P-electrode; Bonding the reinforcement layer to a preset second temporary substrate via a second adhesive layer, and removing the first temporary substrate; Mass transfer is performed through the second temporary substrate, and the semi-finished chip is aligned with the circuit substrate so that the cathode area of ​​the circuit substrate corresponds to the second N electrode connected with a common cathode, and the anode area of ​​the circuit substrate corresponds to the second P electrode respectively, and the chip and the circuit substrate are connected through a bonding process.

2. The method for preparing and converting a RGB three-primary color Micro LED chip according to claim 1, characterized in that: The first epitaxial layer, the second epitaxial layer and the third epitaxial layer are a blue epitaxial layer, a green epitaxial layer and a red epitaxial layer respectively.

3. The method for preparing and converting a RGB three-primary color Micro LED chip according to claim 1, characterized in that: The structures and materials of the first N electrode and the first P electrode on the first epitaxial layer and the second epitaxial layer are the same, and the third epitaxial layer is different. The thicknesses of the first N electrode and the first P electrode on the first epitaxial layer, the second epitaxial layer and the third epitaxial layer are equal.

4. The method for preparing and converting a RGB three-primary color Micro LED chip according to claim 3, characterized in that: The thickness of the first N electrode and the first P electrode on the first epitaxial layer, the second epitaxial layer and the third epitaxial layer are all 30nm-1000nm.

5. The method for preparing and converting a RGB three-primary color Micro LED chip according to claim 3, characterized in that: The first N-electrode on the first epitaxial layer and the first N-electrode on the second epitaxial layer both include an ohmic contact layer, a reflective layer, a cladding layer, an etching stop layer and an adhesion layer which are stacked; The first N-electrode on the third epitaxial layer includes an adhesion layer, an ohmic layer, a cladding layer, an etching stop layer and an adhesion layer which are stacked.

6. The method for preparing and converting a RGB three-primary color Micro LED chip according to claim 1, characterized in that: In the step of bonding the second N electrode and the second P electrode to a preset first temporary substrate through a first bonding layer, and removing the substrate in the target wafer, the step of removing the substrate in the target wafer includes: Using a pre-configured etching solution to corrode the substrate in the target wafer to remove the substrate; The corrosion solution is a solution of NH4OH:H2O2 in a ratio of 1:9, and the corrosion time is 20 min-60 min.

7. The method for preparing and converting a RGB three-primary color Micro LED chip according to claim 1, characterized in that: The second temporary substrate is made of a transparent material, and the second adhesive layer is made of a UV photosensitive material.

8. The method for preparing and converting an RGB three-primary color Micro LED chip according to claim 6, characterized in that: The second temporary substrate is glass or sapphire.

9. An RGB three-primary color Micro LED chip, characterized in that: The RGB three-primary color Micro LED chip is prepared by the method described in any one of claims 1-8.

10. A circuit substrate, characterized in that: Used in the method described in any one of claims 1 to 8 to connect with the RGB three-primary color Micro LED chip.

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