Micro optoelectronic device and method for preparing the same

Abstract

The present invention relates to a micro optoelectronic device and a preparation method thereof, the preparation method comprising forming a first bonding dielectric layer on a light-emitting wafer, opening a first opening at a position corresponding to a first electrode of the light-emitting wafer in the first bonding dielectric layer, forming a first bonding metal block on the first electrode, and the first opening surrounding the first bonding metal block; forming a second bonding dielectric layer on a driving wafer, opening a second opening at a position corresponding to a second electrode of the driving wafer in the second bonding dielectric layer, forming a second bonding metal block on the second electrode, and the second opening surrounding the second bonding metal block; directly bonding the second bonding metal block to the first bonding metal block and directly bonding the second bonding dielectric layer to the first bonding dielectric layer so that the light-emitting unit is bonded to the driving circuit in correspondence; and removing the first growth substrate to expose the light-emitting unit. In the above manner, hybrid bonding reduces bonding temperature, enhances bonding strength, and reduces process difficulty and cost.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic product manufacturing, and in particular to a micro optoelectronic device and a preparation method thereof. Background Art

[0002] Micro LED is a new generation of display technology. Micro LED is composed of an array of micron-sized semiconductor light-emitting units. It is a comprehensive technology that integrates new display technology and light-emitting diode (LED) technology. It has the advantages of self-luminescence, high efficiency, low power consumption, high integration, high stability, and all-weather operation. It is considered to be the most promising next-generation new display. Compared with existing LED liquid crystal displays, Micro LED displays have higher photoelectric efficiency, higher brightness, higher contrast, and lower power consumption, and can also be combined with flexible panels to achieve flexible displays.

[0003] However, due to the small size of Micro LED chips, less than tens of microns, tens of thousands of Micro LED chips are usually required to form a display panel. There are difficulties in mass transfer in this process, which hinders the progress of Micro LED industrialization. There is also a method of directly bonding two wafers with a metal layer on the entire surface to avoid mass transfer, but the bonding process temperature of this process is generally 100-200℃, and a high temperature annealing temperature of more than 400℃ is required to strengthen the electrode. At the same time, direct metal bonding will introduce greater stress, making the wafer easily damaged during the bonding process; in addition, in order to ensure the bonding quality, the bonding layer usually used is thicker, which will also increase the cost and bring difficulties to the industrial development.

[0004] In view of this, it is necessary to provide a new micro optoelectronic device and a preparation method thereof to solve the defects of the prior art. Summary of the invention

[0005] Based on this, the present invention provides a micro optoelectronic device and a method for preparing the same, which can reduce the bonding temperature and enhance the bonding strength through a hybrid bonding method, and can also reduce the process difficulty and cost.

[0006] The present invention provides a method for preparing a micro optoelectronic device, comprising:

[0007] A first bonding dielectric layer is formed above the light-emitting wafer, a first opening is opened at a position of the first bonding dielectric layer corresponding to the first electrode of the light-emitting wafer, a first bonding metal block is formed on the first electrode, the first opening is arranged around the first bonding metal block, the light-emitting wafer comprises a first growth substrate and a plurality of light-emitting units grown on the first growth substrate and arranged in an array, and a first electrode is formed on each of the light-emitting units;

[0008] A second bonding dielectric layer is formed above the driving wafer, a second opening is opened at a position of the second bonding dielectric layer corresponding to the second electrode of the driving wafer, a second bonding metal block is formed on the second electrode, the second opening is arranged around the second bonding metal block, the driving wafer includes a second growth substrate and a plurality of driving circuits grown on the second growth substrate and corresponding to the light-emitting units one by one, and a second electrode is formed on each of the driving circuits;

[0009] The light emitting unit is correspondingly bonded to the driving circuit by directly bonding the second bonding metal block to the first bonding metal block and directly bonding the second bonding dielectric layer to the first bonding dielectric layer;

[0010] And, removing the first growth substrate to expose the light emitting unit.

[0011] Preferably, the second bonding dielectric layer and the first bonding dielectric layer are made of a material selected from the group consisting of bis(benzocyclobutene), phenolic resin, acrylic acid and polyurethane.

[0012] Preferably, the second bonding dielectric layer and the first bonding dielectric layer are made of photosensitive polyimide material.

[0013] Preferably, the step of bonding the light emitting unit to the driving circuit includes plasma activating surfaces of the first bonding dielectric layer, the second bonding dielectric layer, the first bonding metal block and the second bonding metal block.

[0014] Preferably, the method of bonding the light-emitting unit to the driving circuit also includes aligning the light-emitting wafer and the driving wafer face to face, and then bonding the light-emitting unit to the driving circuit at a temperature of 200°C-250°C and a pressure of 250-300KN for 2-3h.

[0015] Preferably, the second bonding metal block and the first bonding metal block are made of at least one material selected from the group consisting of Au, Sn, In and Cu.

[0016] Preferably, the second bonding metal block and the first bonding metal block are further made of at least one material selected from the group consisting of Ti, TiW, Ta and TaN.

[0017] Preferably, the first bonding metal block gradually shrinks from the first electrode toward a side away from the light-emitting wafer; and / or the second bonding metal block gradually shrinks from the second electrode toward a side away from the driving wafer.

[0018] Preferably, the first bonding metal block extends out of the first opening, and the second bonding metal block is in the second opening;

[0019] And / or, the second bonding metal block extends out of the second opening, and the first bonding metal block is in the first opening.

[0020] The present invention also provides a micro optoelectronic device, which is prepared by any of the above preparation methods.

[0021] The beneficial effect of the present invention is to provide a micro optoelectronic device and a preparation method thereof, the preparation method comprising forming a first bonding dielectric layer above a light-emitting wafer, opening a first opening at a position corresponding to the first electrode of the light-emitting wafer in the first bonding dielectric layer, forming a first bonding metal block on the first electrode, and the first opening surrounding the first bonding metal block; forming a second bonding dielectric layer above a driving wafer, opening a second opening at a position corresponding to the second electrode of the driving wafer in the second bonding dielectric layer, forming a second bonding metal block on the second electrode, and the second opening surrounding the second bonding metal block; directly bonding the second bonding metal block to the first bonding metal block and directly bonding the second bonding dielectric layer to the first bonding dielectric layer so that the light-emitting unit is bonded to the driving circuit in correspondence; and removing the first growth substrate to expose the light-emitting unit. In the above manner, hybrid bonding can reduce the bonding temperature, while also enhancing the bonding strength, and can also reduce the process difficulty and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a micro optoelectronic device according to an embodiment of the present invention;

[0023] Figure 2-12 This is a process flow chart of a method for preparing a micro optoelectronic device according to an embodiment of the present invention;

[0024] The meanings of the symbols in the accompanying drawings are:

[0025] 100-micro optoelectronic device; 1-light-emitting wafer; 11-first growth substrate; 12-light-emitting unit; 13-first electrode; 2-first bonding dielectric layer; 21-first opening; 3-first bonding metal block; 4-driving wafer; 41-second growth substrate; 42-driving circuit; 43-second electrode; 5-second bonding dielectric layer; 51-second opening; 6-second bonding metal block. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the 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 understanding of the disclosure of the present invention more thorough and comprehensive.

[0027] 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 an intermediate 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 an intermediate element at the same time.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] like Figure 1 As shown, it is a schematic diagram of the structure of a micro optoelectronic device 100 according to an embodiment of the present invention. The micro optoelectronic device 100 includes a second growth substrate 41, a plurality of driving circuits 42, and a plurality of light-emitting units 12 corresponding to the plurality of driving circuits 42. The light-emitting unit 12 is provided with a plurality of first electrodes 13, and the first electrode 13 includes a P electrode provided for each light-emitting unit 12, and an N electrode shared by all the light-emitting units 12. A plurality of second electrodes 43 corresponding to the first electrode 13 are provided on the driving circuit 42, and the first electrode 13 and the second electrode 43 are bonded and connected by a bonding metal block, and the non-electrode between the light-emitting units 12 is filled with a bonding dielectric layer, and the bonding dielectric layer is flush with the side of the light-emitting unit 12 away from the second growth substrate 41, and the first growth substrate 11 on the light-emitting unit 12 is peeled off. The bonding metal block includes a first bonding metal block 6 provided on the first electrode 13 and a second bonding metal block 6 provided on the second electrode 43. Optionally, the material of the bonding metal block includes but is not limited to at least one of Au, Sn, In, and Cu, preferably Cu. Optionally, the material of the bonding metal block also includes but is not limited to at least one of Ti, TiW, Ta, and TaN to prevent the migration of the previous metal. The bonding dielectric layer includes a first bonding dielectric layer 2 disposed on the first growth substrate 11 and a second bonding dielectric layer 5 disposed on the second growth substrate 41. Optionally, the material of the bonding dielectric layer includes but is not limited to at least one of bis-benzocyclobutene, phenolic resin, acrylic acid, polyurethane, and silicon wafer; preferably, it is made of photosensitive polyimide material.

[0030] like Figures 2 to 12 As shown, it is the steps of the preparation method of the micro optoelectronic device 100 according to an embodiment of the present invention.

[0031] The method for preparing the micro optoelectronic device 100 comprises the following steps:

[0032] In step S100, a first bonding dielectric layer 2 is formed above the light-emitting wafer 1, a first opening 21 is opened at a position corresponding to the first bonding dielectric layer 2 and the first electrode 13 of the light-emitting wafer 1, a first bonding metal block 6 is formed on the first electrode 13, and the first opening 21 is surrounded by the first bonding metal block 6.

[0033] The light-emitting wafer 1 of the present invention includes a first growth substrate 11 and a plurality of light-emitting units 12 grown on the first growth substrate 11 and arranged in an array, and a first electrode 13 is formed on each light-emitting unit 12. Specifically, taking micro LED as an example, the first growth substrate 11 includes but is not limited to sapphire (Al2O3) and spinel (MgAl2O4) which are insulating and can be used for the epitaxial structure growth material of the light-emitting unit 12, and a plurality of light-emitting units 12 are formed by imaging the epitaxial structure. The light-emitting wafer 1 of the embodiment of the present invention includes a plurality of P electrodes and a common N electrode. Specifically, each light-emitting unit 12 of the light-emitting wafer 1 corresponds to an electrode, which is the P electrode, and the N electrode surrounds all the light-emitting units 12, and all the light-emitting units 12 share one N electrode.

[0034] In addition, the material of the first bonding dielectric layer 2 includes but is not limited to at least one of bis-benzocyclobutene, phenolic resin, acrylic acid, polyurethane, and silicon wafer; preferably, it is made of photosensitive polyimide material, which not only acts as a photoresist but also has good insulation and adhesion, and can enhance bonding force and reduce metal bonding temperature. The material of the first bonding metal block 6 includes but is not limited to at least one of Au, Sn, In, and Cu, preferably Cu. Optionally, the material of the first bonding metal block 6 also includes but is not limited to at least one of Ti, TiW, Ta, and TaN to prevent the migration of the previous metal.

[0035] In step S200, a second bonding dielectric layer 5 is formed above the driving wafer 4, a second opening 51 is opened at a position corresponding to the second bonding dielectric layer 5 and the second electrode 43 of the driving wafer 4, a second bonding metal block 6 is formed on the second electrode 43, and the second opening 51 is surrounded by the second bonding metal block 6.

[0036] The driving wafer 4 of the present invention is CMO driven, and includes a second growth substrate 41 and a plurality of driving circuits 42 grown on the second growth substrate 41 and corresponding to the light-emitting units 12 one by one, and a second electrode 43 is formed on each driving circuit 42. In order to be bonded to the light-emitting wafer 1, the electrode arrangement of the driving circuit 42 is the same as and corresponding to the light-emitting wafer 1. The second growth substrate can be a glass substrate, a flexible polyimide or a parylene substrate.

[0037] In addition, in an embodiment of the present invention, the second bonding dielectric layer 5 is made of the same material as the first bonding dielectric layer 2, and the second bonding metal block 6 can be made of the same or different material as the first bonding metal block 6. And similarly, the material of the second bonding dielectric layer 5 includes but is not limited to one of bis-benzocyclobutene, phenolic resin, acrylic acid, and polyurethane; preferably, it is made of photosensitive polyimide material. The material of the second bonding metal block 6 includes but is not limited to at least one of Au, Sn, In, and Cu, preferably Cu. Optionally, the material of the second bonding metal block 6 also includes but is not limited to at least one of Ti, TiW, Ta, and TaN to prevent the migration of the previous metal.

[0038] In step S300 , the light emitting unit 12 is bonded to the driving circuit 42 by directly bonding the second bonding metal block 6 to the first bonding metal block 6 and directly bonding the second bonding dielectric layer to the first bonding dielectric layer.

[0039] By matching steps S100 and S200 face to face and utilizing the bonding of the second bonding dielectric layer to the first bonding dielectric layer, the bonding temperature between the second bonding metal block 6 and the first bonding metal block 6 can be reduced, and the bonding strength between the electrodes can be enhanced.

[0040] Step S400 , removing the first growth substrate 11 to expose the light emitting unit 12 .

[0041] Optionally, the first growth substrate 11 is removed by laser stripping, wet etching or mechanical cutting.

[0042] In an optional embodiment, the first bonding metal block 6 gradually shrinks from the first electrode 13 toward the side away from the light-emitting wafer 1, and / or the second bonding metal block 6 gradually shrinks from the second electrode 43 toward the side away from the driving wafer 4. In short, at least one of the first bonding metal block 6 and the second bonding metal block 6 has a shape that conforms to each other, so that the area of ​​the metal block on the bonding side is small, which is beneficial to the bonding of the first bonding metal block 6 and the second bonding metal block 6. Optionally, the first bonding metal block 6 extends out of the first opening 21, that is, the height of the first bonding metal block 6 is higher than the first bonding dielectric layer 2, and the second bonding metal block 6 is in the second opening 51, that is, the height of the second bonding metal block 6 is lower than the second bonding dielectric layer 5; and / or, the second bonding metal block 6 extends out of the second opening 51, and the first bonding metal block 6 is in the first opening 21. In short, keeping one extending out of the hole and the other in the hole is beneficial to subsequent bonding.

[0043] In an optional embodiment, before step S300, step S310 is further included, in which surfaces of the first bonding dielectric layer 2, the second bonding dielectric layer 5, the first bonding metal block 6 and the second bonding metal block 6 are activated respectively by a plasma activation method.

[0044] In an optional embodiment, step S300 also includes step S320, after the light-emitting wafer 1 and the driving wafer 4 are face-to-face aligned, the temperature is 200° C.-250° C., the pressure is 250-300 KN, and the treatment is performed for 2-3 hours to bond the light-emitting unit 12 to the driving circuit 42.

[0045] Through the above method, the first bonding dielectric layer 2 and the second bonding dielectric layer 5 belong to the bonding of adhesive, and the first bonding metal block 6 and the second bonding metal block 6 are metal eutectic bonding. These two mixed bonding methods are to place an organic adhesive between the two wafer surfaces, and then form an intermediate layer with a certain bonding strength through curing treatment, so that the two wafers are closely attached. Under a certain bonding temperature and pressure, the metal bonding will turn into a liquid state and undergo solid-liquid diffusion at the bonding interface, thereby forming a stable electrical interconnection structure of one or more intermetallic compounds, which can greatly reduce the bonding temperature. In addition, plasma activation combined with wet chemical treatment can effectively reduce the annealing temperature to 150-300°C to obtain a high-strength bond.

[0046] Example

[0047] Step S1, clean the Micro LED sapphire substrate after epitaxial wafer patterning with pure water, and then dehydrate and bake it. Spin-coat the Micro LED sapphire substrate with photosensitive polyimide at 1.5um, and then vacuum dry at 0-5pa / 110±10℃ / 120s, and expose it to 80-100mj / cm2 of ultraviolet light at 365nm wavelength. 2 , 2.38% tetramethylammonium hydroxide solution developed for 60-90s, ultrapure water cleaned for 30s, thermally cured at 250℃ / 3600s, and the polyimide film above the sapphire electrode area and the cutting path was opened. The Micro LED sapphire substrate was sputtered in sequence using magnetron sputtering Titanium as a bonding metal barrier layer, copper, Tin is used as bonding metal layer.

[0048] Step S2, patterning the Ti / Cu / Sn layer on the Micro LED sapphire substrate, washing with ultrapure water for 30 seconds, spin coating with positive photoresist 1.3-1.5um, hot plate baking at 90±10℃ / 120s, and exposure to 365nm wavelength ultraviolet light at 60-90mj / cm 2 , developed with 2.38% tetramethylammonium hydroxide solution for 60-90s, washed with ultrapure water for 30s and dried, and then baked at 90±10℃ / 150s. Finally, the photoresist pattern was retained above the LED P / N type top electrode, and the photoresist in other positions was developed and removed.

[0049] Step S3, the Ti / Cu / Sn composite metal layer is patterned by wet etching of the Micro LED sapphire substrate sapphire, and a hydrogen peroxide-based (8-12% hydrogen peroxide and sulfuric acid mixture as the main oxidant, 5-10% citric acid as the auxiliary oxidant, 0.01-5% ethylenediaminetetraacetic acid as the chelating agent, 0.01-5% phenylurea as the stabilizer, 5-10% diammonium hydrogen phosphate as the inorganic salt, and the rest is deionized water) etching solution is used as the Ti / Cu / Sn composite metal structure wet etching solution. The etching solution is continuously sprayed on the substrate for 30-80 seconds, and then ultrapure water is used for cleaning for 30 seconds and dried to remove the titanium copper film layer in the area not protected by the photoresist.

[0050] Step S4, using RIE plasma ashing process to remove the positive photoresist on the substrate, introducing oxygen 1 LPM, discharge power 200 W, reaction time 80-120 s, and activating the exposed polyimide and copper / tin layers on the sapphire substrate at the same time.

[0051] Step S5: After the substrate film layer of the driving backplane is cleaned with ultrapure water, a photosensitive polyimide is spin-coated at 1.5um, vacuum low-pressure drying is performed at 0-5pa / 110±10℃ / 120s, and 365nm wavelength ultraviolet light is exposed at 80-100mj / cm 2 , 2.38% tetramethylammonium hydroxide solution developed for 60-90s, ultrapure water cleaned for 30s, thermally cured at 250℃ / 3600s, and the polyimide film on the pixel electrode, pad area and cutting path of the driver backplane substrate was opened. The driver backplane substrate was sputtered in sequence by magnetron sputtering. Titanium as a bonding metal barrier layer, copper, Tin is used as bonding metal layer.

[0052] Step S6, similarly, the Ti / Cu / Sn bonding metal layer of the driving backplane substrate is patterned, and ultrapure water cleaning is performed for 30 seconds, positive photoresist 1.3-1.5um is spin-coated, hot plate baking is performed at 90±10℃ / 120s, and 365nm wavelength ultraviolet light exposure is performed at 60-90mj / cm 2 , developed with 2.38% tetramethylammonium hydroxide solution for 60-90s, cleaned with ultrapure water for 30s and dried, and then baked at 90±10℃ / 150s. Finally, the photoresist pattern was retained on the top electrode of the driving backplane substrate and above the Pad, and the photoresist in other positions was developed and removed.

[0053] Step S7, wet-etching the top titanium / copper composite structure of the driving backplane substrate using hydrogen peroxide-based etching solution. The etching solution is continuously sprayed on the driving backplane substrate for 30-80 seconds, then cleaned with ultrapure water for 30 seconds and dried to remove the titanium-copper film layer in the area not protected by the photoresist.

[0054] Step S8, using RIE plasma ashing to remove the positive photoresist on the substrate, introducing 1 LPM of oxygen and argon mixed gas, discharging power 200 W, reaction time 80-120 s, and at the same time performing surface activation on the exposed polyimide and copper / tin layers on the driving backplane substrate.

[0055] Step S9, the Micro LED sapphire substrate and the driving backplane substrate after surface activation are cleaned with ultrapure water for 30 seconds, and then the two wafers are face-to-face bonded, with a bonding temperature of 250°C, a bonding pressure of 250KN, and a bonding time of 7200s.

[0056] Step S10: Use laser lift-off technology to focus the laser beam on the GaN buffer layer after bonding, decompose the GaN structure into nitrogen and metal gallium ions, and then use dilute hydrochloric acid to clean the sapphire wafer to remove residual gallium ions. Perform annealing at 200℃ / 2H on the bonded wafer. Use PECVD process to deposit the top layer of LED area on the bonded wafer with the sapphire substrate peeled off. SIO2.

[0057] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0058] The above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. 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 a micro optoelectronic device, characterized in that: include: A first bonding dielectric layer is formed above the light-emitting wafer, a first opening is opened at a position of the first bonding dielectric layer corresponding to the first electrode of the light-emitting wafer, a first bonding metal block is formed on the first electrode, the first opening is arranged around the first bonding metal block, the light-emitting wafer comprises a first growth substrate and a plurality of light-emitting units grown on the first growth substrate and arranged in an array, and a first electrode is formed on each of the light-emitting units; A second bonding dielectric layer is formed above the driving wafer, a second opening is opened at a position of the second bonding dielectric layer corresponding to the second electrode of the driving wafer, a second bonding metal block is formed on the second electrode, the second opening is arranged around the second bonding metal block, the driving wafer comprises a second growth substrate and a plurality of driving circuits grown on the second growth substrate and corresponding to the light-emitting units one by one, and a second electrode is formed on each of the driving circuits; The light-emitting unit is correspondingly bonded to the driving circuit by directly bonding the second bonding metal block to the first bonding metal block and directly bonding the second bonding dielectric layer to the first bonding dielectric layer, wherein there is a height difference between a bonding interface between the second bonding metal block and the first bonding metal block and a bonding interface between the second bonding dielectric layer and the first bonding dielectric layer; wherein the bonding process between the second bonding metal block and the first bonding metal block includes solid-liquid diffusion at the bonding interface, and the bonding process between the second bonding dielectric layer and the first bonding dielectric layer includes a curing process to form an intermediate layer; And, removing the first growth substrate to expose the light emitting unit.

2. The method for preparing a micro optoelectronic device according to claim 1, characterized in that: The second bonding dielectric layer and the first bonding dielectric layer are made of one material selected from the group consisting of bis-benzocyclobutene, phenolic resin, acrylic acid and polyurethane.

3. The method for preparing a micro optoelectronic device according to claim 2, characterized in that: The second bonding dielectric layer and the first bonding dielectric layer are made of photosensitive polyimide material.

4. The method for preparing a micro optoelectronic device according to claim 1, characterized in that: The step of bonding the light emitting unit to the driving circuit may include plasma activating surfaces of the first bonding dielectric layer, the second bonding dielectric layer, the first bonding metal block, and the second bonding metal block.

5. The method for preparing a micro optoelectronic device according to claim 4, characterized in that: The method of bonding the light-emitting unit to the driving circuit also includes aligning the light-emitting wafer and the driving wafer face to face, and then bonding the light-emitting unit to the driving circuit at a temperature of 200°C-250°C and a pressure of 250-300KN for 2-3 hours.

6. The method for preparing a micro optoelectronic device according to claim 1, characterized in that: The second bonding metal block and the first bonding metal block are made of at least one material selected from Au, Sn, In, and Cu.

7. The method for preparing a micro optoelectronic device according to claim 4, characterized in that: The second bonding metal block and the first bonding metal block are further made of at least one material selected from the group consisting of Ti, TiW, Ta, and TaN.

8. The method for preparing a micro optoelectronic device according to claim 1, characterized in that: The first bonding metal block gradually shrinks from the first electrode toward a side away from the light emitting wafer; and / or the second bonding metal block gradually shrinks from the second electrode toward a side away from the driving wafer.

9. The method for preparing a micro optoelectronic device according to claim 1, characterized in that: The first bonding metal block extends out of the first opening, and the second bonding metal block is in the second opening; And / or, the second bonding metal block extends out of the second opening, and the first bonding metal block is in the first opening.

10. A micro optoelectronic device, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 9.

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