CN113270441B

CN113270441B - LED chip structure, preparation method thereof, display module and electronic equipment

Info

Publication number: CN113270441B
Application number: CN202110582033.1A
Authority: CN
Inventors: 刘召军; 邱成峰; 莫炜静; 刘时彪
Original assignee: Shenzhen Stan Technology Co Ltd
Current assignee: Shenzhen Stan Technology Co Ltd
Priority date: 2021-05-27
Filing date: 2021-05-27
Publication date: 2022-12-13
Anticipated expiration: 2041-05-27
Also published as: CN113270441A

Abstract

The invention discloses an LED chip structure and a preparation method thereof, a display module and electronic equipment, wherein the LED chip structure comprises a first N-type layer and an LED column array formed on the first N-type layer and composed of a plurality of LED columns, the LED column array is divided into different color blocks by insulating fillers filled in gaps among partial LED columns, each color block comprises not less than 2 LED columns, corresponding light-emitting materials are filled in the gaps among the LED columns in each color block, the first N-type layer is provided with spacing grooves corresponding to the positions of the insulating fillers, the spacing grooves are used for enabling the first N-type layers of the color blocks to be not connected with each other, each color block also comprises an N electrode electrically connected with the first N-type layers of the color blocks, and the N electrode supplies power to all the LED columns in the color blocks, so that each color block can independently emit light under the action of electric drive. The invention can prepare the LED chip structure with tiny size, higher resolution, more bright color and low power consumption, and the preparation process can overcome the process difficulty caused by tiny size.

Description

LED chip structure, preparation method thereof, display module and electronic equipment

Technical Field

The invention relates to the technical field of LED display, in particular to an LED chip structure, a preparation method of the LED chip structure, a display module and electronic equipment.

Background

With the pursuit of high definition display by human, micro-leds and nano-leds have attracted great interest. As a novel display technology, the micro led/nano led has many advantages of self-luminescence, high efficiency, long service life, ultrahigh resolution, etc., and since birth, people are keen on it and praised as a next-generation display technology.

In the process of studying full-color LED chips, the inventors found that the full-color LED chips have at least the following problems: the full-color LED chip structure is formed by periodically arranging LED chips with different light-emitting colors, the LED chips with different light-emitting colors usually comprise electroluminescent LED chips and photoluminescent bodies which are compounded on the electroluminescent LED chips and can emit light with different colors, the intensity of exciting light emitted by the electroluminescent LED chips can be controlled by controlling the input current of the electroluminescent LED chips, the photoluminescent bodies can emit light with different wavelengths by being excited by the exciting light with different intensities, so that different light-emitting colors are presented, however, for micro LEDs/nano LEDs, especially for nano LEDs, the chip size is smaller than 1 micron and enters the nano level, the independent control of each nano LED is difficult to realize, and the patterning, film coating, photoetching, alloying and the like of each nano LED are difficult.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, and provides an LED chip structure, a preparation method thereof and a display module, so that the process difficulty is reduced.

In order to achieve the purpose, the technical scheme of the invention is as follows:

an LED chip structure comprises a first N-type layer and an LED column array formed on the first N-type layer and composed of a plurality of LED columns, wherein each LED column comprises a second N-type layer, an active layer and a P-type layer which are sequentially laminated to the first N-type layer, the LED column array is divided into different color blocks by insulating fillers filled in gaps among partial LED columns, each color block comprises not less than 2 LED columns, and corresponding luminescent materials are filled in the gaps among the LED columns in each color block,

the first N-type layer is provided with spacing grooves corresponding to the positions of the insulating fillers, the spacing grooves are used for enabling the first N-type layers of the color blocks to be not connected with each other, each color block further comprises an N electrode electrically connected with the first N-type layers of the color blocks, and the N electrode supplies power to all the LED columns in the color blocks, so that each color block can be driven to emit light independently through electricity.

The invention also provides a preparation method of the LED chip structure, which comprises the following steps:

providing a substrate, wherein the substrate comprises a substrate, a first N-type layer laminated to the substrate and an LED column array formed on the first N-type layer and composed of a plurality of LED columns, and each LED column comprises a second N-type layer, an active layer and a P-type layer which are sequentially laminated to the first N-type layer;

filling insulating fillers in gaps among partial LED columns so as to space the LED column array into different color blocks, wherein each color block comprises a plurality of LED columns;

filling corresponding luminescent materials in gaps of the LED columns in the color blocks;

removing the substrate to expose the first N-type layer;

forming a spacing groove on the exposed first N-type layer and at a position corresponding to the position of the insulating filler, wherein the spacing groove is used for enabling the first N-type layers of the color blocks not to be connected with each other;

and preparing N electrodes electrically connected with the first N type layers of the color blocks, wherein the N electrodes supply power to all the LED columns in the color blocks, so that each color block can emit light by independent electric drive.

The invention also discloses a display module comprising the LED chip structure or the LED chip structure prepared by the preparation method.

The invention also discloses electronic equipment comprising the display module.

The embodiment of the invention has the following beneficial effects:

1. according to the invention, the first N-type layer and the LED column array formed by the LED columns and formed on the first N-type layer are arranged, so that the problem that the micro LED is difficult to manufacture is solved, and the technical effect of forming large-scale LED columns in batches can be achieved;

2. by filling the luminescent material in the gaps between the LED columns, on one hand, the technical problem that a mask with extremely high precision is required to be used in filling is solved, the mask with extremely high precision is not required to be used in filling, and the technical effects of difficult process and increased process cost caused by over-small size are avoided; on the other hand, because the light is emitted through the side surface, the problem that the light emitting surfaces at two ends are too small is solved, and the technical effects of increasing the light emitting area and improving the conversion efficiency of photoluminescence are realized;

3. the problem of difficult process of the micro display device is solved by dividing different color blocks and filling the luminescent materials of the color blocks in batches;

4. by arranging the insulating filler and arranging the spacing grooves on the first N-type layer, the color blocks are electrically isolated, so that the input current of each color block can be independently controlled, and full colorization is realized;

5. through setting up the N electrode of being connected with the first N type layer electricity of each colour lump for the N electrode can be for all LED post power supplies in the colour lump, has solved the technical problem of carrying out control alone to every LED post, avoids setting up the graphical degree of difficulty that the N electrode brought to every LED post.

In conclusion, the invention can prepare the LED chip structure with tiny size, higher resolution, more bright color and low power consumption, and the preparation process can overcome the process difficulty caused by tiny size.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Wherein:

fig. 1 is a schematic structural diagram of an epitaxial wafer with a current spreading layer formed thereon according to an embodiment of the present invention.

Fig. 2 is a schematic diagram of a structure for etching the structure shown in fig. 1 to form an array of LED pillars.

Fig. 3 is a schematic view of the structure of fig. 2 filled with a light emitting material and an insulating filler.

Fig. 4 is a schematic structural view of the P electrode formed by the structure shown in fig. 3.

Fig. 5 is a schematic view of the structure of fig. 4 with the substrate and buffer layer removed.

Fig. 6 is a schematic structural view of roughening the light emitting surface and forming the isolation grooves in the structure shown in fig. 5.

Fig. 7 is a schematic structural view of a passivation layer formed on the structure shown in fig. 6.

Fig. 8 is a schematic structural view of the structure shown in fig. 7 forming an N electrode.

Fig. 9 is a schematic top view of the structure shown in fig. 8.

The LED structure comprises a substrate 10, a buffer layer 20, an N-type layer 30, a first N-type layer 31, a second N-type layer 32, an LED column 40, an active layer 41, a P-type layer 42, a current expansion layer 43, a color block 50, an insulating filler 60, a luminescent material 70, a P electrode 80, a metal layer 81, a conductive substrate 82, a light-emitting surface 33, a spacing groove 34, a passivation layer 35 and an N electrode 90.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 8 and 9, the present invention discloses an LED chip structure, which includes a first N-type layer 31 and an LED pillar array formed on the first N-type layer 31 and composed of a plurality of LED pillars 40, where the LED pillars 40 include a second N-type layer 32, an active layer 41, and a P-type layer 42 sequentially stacked on the first N-type layer 31, the LED pillar array is partitioned into different color blocks 50 by insulating fillers 60 filled in gaps between some of the LED pillars 40, each color block 50 includes not less than 2 LED pillars 40, gaps of the LED pillars 40 in each color block 50 are filled with corresponding light-emitting materials 70, the first N-type layer 31 is provided with a partition groove 34 corresponding to a position of the insulating filler 60, the partition groove 34 is used for making the first N-type layers 31 of the color blocks 50 not connected to each other, each color block 50 further includes N electrodes 90 electrically connected to the first N-type layers 31 of the color blocks 50, the N electrodes 90 supply power to all the LED pillars 40 in the color blocks 50, thereby realizing that each color block 50 can emit light individually.

The invention can form large-scale LED columns 40 in batch by arranging the first N-type layer 31 and the LED column array formed on the first N-type layer 31 and consisting of a plurality of LED columns 40; by filling the luminescent material 70 in the gap between the LED pillars 40, on one hand, a mask with extremely high precision is not needed during filling, thereby avoiding the process difficulty and the process cost increase caused by too small size, and on the other hand, compared with the luminescent material 70 arranged above the LED in the prior art, the luminescent material 70 of the present invention has a larger contact area with the LED pillars 40, thereby improving the conversion efficiency of photoluminescence; by dividing different color blocks 50, the luminescent material 70 of each color block 50 can be filled in batches, and the process difficulty caused by over-small size is avoided due to the larger size of each color block 50; by arranging the insulating filler 60 and the spacing grooves 34 on the first N-type layer 31, the color blocks 50 are electrically isolated, so that the input current of each color block 50 can be independently controlled, and full colorization is realized; the N electrodes 90 electrically connected with the first N type layers 31 of the color blocks 50 are arranged, so that the N electrodes 90 can supply power to all the LED columns 40 in the color blocks 50, and the difficulty in patterning caused by arranging the N electrodes 90 on each LED column 40 is avoided due to the large area of each color block 50. In conclusion, the invention can prepare the LED chip structure with tiny size, higher resolution, more bright color and low power consumption, and the preparation process can overcome the process difficulty caused by tiny size.

In the above embodiment, the LED pillar array may be a regular array, such as N rows, M columns, or concentric circles, or an irregular array, preferably a regular array, which is beneficial to uniform distribution of the LED pillars 40 in each color patch 50 and can provide uniform light emission color.

Referring to fig. 8, in one embodiment, a P electrode 80 is further included, and the P electrode 80 is electrically connected to the P-type layers 42 of all the LED pillars 40 of all the color patches 50, that is, the P electrode 80 is shared by all the color patches 50, which is beneficial for batch preparation of the P electrode 80 and simplification of the preparation process of the P electrode 80, and the P electrode 80 can be any P electrode structure in the prior art.

Referring to fig. 8, further, in an embodiment, the P-electrode 80 includes a metal layer 81 stacked on all the LED pillars 40 of all the color patches 50, the insulating filler 60 and the light emitting material 70, and a conductive substrate 82 bonded to the metal layer 81, the metal layer 81 is electrically connected to the P-type layers of all the LED pillars 40 of all the color patches 50, and the conductive substrate 82 can provide heat dissipation for the metal layer 81, improve current uniformity, reduce internal resistance, and improve heat dissipation and low power consumption of the whole device.

Further, in one embodiment, the conductive substrate 82 may be a silicon substrate or a copper substrate.

Referring to fig. 5 and 6, a surface of the first N-type layer 31 facing away from the LED pillar 40 is a light exit surface 33, and in order to improve the light extraction efficiency of the light exit surface 33, in an embodiment, the light exit surface 33 is preferably provided as a roughened surface.

Referring to fig. 8, in an embodiment, the light source module further includes a passivation layer 35 covering the light emitting surface 33 and filling the spacing groove 34, the passivation layer 35 filling the spacing groove 34 prevents the first N-type layers 31 of the color blocks 50 from being electrically connected to each other, and the passivation of the light emitting surface 33 and the filling of the spacing groove 34 are achieved through one process step, so that the manufacturing process is optimized, and the cost is saved. Of course, the spacer 34 may be filled with other materials than the passivation layer 35.

Further, in one embodiment, the passivation layer 35 is preferably a transparent insulating material that does not affect light extraction. Specifically, the passivation layer 35 may be silicon dioxide, silicon nitride, or the like.

Referring to fig. 8 and 9, the N electrode 90 is provided for each color patch 50, and since the color patch 50 includes a plurality of LED pillars 40, the size is increased, the size of the N electrode 90 does not have to be too small, and the process difficulty is reduced. The number of the N electrodes 90 of each color patch 50 is at least 1, and when the number of the N electrodes 90 is plural, the N electrodes 90 are uniformly or symmetrically distributed, for example, the number of the N electrodes 90 may be 1, 2, or more than 2, and when the number of the N electrodes 90 is greater than or equal to 2, the plurality of electrodes may be symmetrically distributed about the central axis or the symmetry axis of the color patch 50, or may be uniformly distributed about the central axis of the color patch 50, or may be uniformly distributed on the color patch 50, and since the N electrodes 90 supply power to all the LED pillars 40 in the color patch 50, the N electrodes 90 are uniformly or symmetrically distributed, the uniformity of the current distributed to the respective LED pillars 40 may be improved.

Referring to fig. 9, in the present embodiment, the number of N electrodes 90 is 2, and the N electrodes are respectively disposed at two ends of the color block 50.

In one embodiment, the insulating filler 60 is a transparent insulating filler, and particularly, the material of the transparent insulating filler may be silicon dioxide or silicon nitride, which also has the function of passivating the sidewalls of the LED pillar 40.

In another embodiment, the insulating filler 60 is opaque insulating filler or reflective insulating filler, so as to prevent light cross-talk between different colors of light of adjacent color blocks.

Specifically, in one embodiment, the material of the opaque insulating filler may be an opaque resin material or the like.

In a specific embodiment, the reflective insulating filler comprises a metal reflective main body and a light-transmitting insulating layer covering the side surfaces and the bottom surface of the metal reflective main body, the light-transmitting insulating layer is in contact with the side walls of the LED columns and the bottoms of the gaps between the adjacent LED columns, so that the LED columns and the metal reflective main body can be electrically insulated, and the metal reflective main body reflects light back to each color block again, thereby avoiding the phenomenon of light crosstalk between different colors of the adjacent color blocks and mutual influence.

The metal light reflecting main body can be made of aluminum, gold and the like, and the light transmitting insulating layer can be made of silicon dioxide, silicon nitride and the like.

The preparation method of the reflective insulation filler can be as follows: a light-transmitting insulating layer is formed on the bottom of a gap between partial LED columns of a provided substrate and the side walls of the LED columns, and then a metal light-reflecting main body is continuously formed on the light-transmitting insulating layer to fill the gap between the LED columns, so that light-reflecting insulating filler filled in the gap between the partial LED columns is formed. The method of forming the light-transmitting insulating layer may be a sputtering method or a deposition method, and the method of forming the metal light-reflecting body may also be a sputtering method or a deposition method.

Of course, the insulating filler 60 may be an air layer, and the air layer also has an insulating effect. In a specific embodiment, the diameter of the LED pillar 40 may be 1000nm to 1nm, and the distance between adjacent LED pillars 40 is 10000nm to 100nm, preferably, the diameter of the LED pillar 40 may be 1000nm to 10nm, and the distance between adjacent LED pillars 40 is 1000nm to 100nm, in this case, the LED pillar 40 is an LED nanopillar, and the smaller the diameter of the LED pillar 40 is, the smaller the distance between adjacent LED pillars 40 is, the smaller the size of the manufactured single LED is, and the higher the resolution of the device is.

In a specific embodiment, the luminescent material 70 may be a fluorescent material, a quantum dot material, a transparent material, or the like, for a nano led with a smaller size, the luminescent material 70 may be a quantum dot material with a nanometer size, and for a micro led with a larger size, the luminescent material 70 may be a fluorescent material with a micrometer size. Of course, the fluorescent material can also be prepared into a nano size for the preparation of the NanoLED.

In a specific embodiment, the full LED chip structure is obtained by: the LED columns 40 are blue LED columns, the number of color blocks 50 is 3, and the luminescent material 70 of each color block 50 is a red luminescent material, a green luminescent material, and a transparent material, respectively. In this specific embodiment, the blue LED pillar can emit blue light, which may be a GaN semiconductor material, for example, includes an N-GaN N-type layer, an InGaN/GaN blue light multi-quantum hydrazine active layer, and a P-GaN P-type layer stacked in sequence to the first N-type layer 31, one color block 50 is a blue LED pillar combined with a red light emitting material to obtain a blue and red light combined light, one color block 50 is a blue LED pillar combined with a green light emitting material to obtain a blue and green light combined light, one color block 50 is a blue LED pillar combined with a transparent material, blue light emitted by the blue LED pillar is transmitted through the transparent material to mainly obtain a blue light, input currents of the three color blocks 50 are individually controlled, and RGB full-color display can be achieved. For each color block 50, as the light is compounded, the color of the light can be richer, and the color gorgeous degree of the device is improved.

Of course, in other practical embodiments, two color blocks 50 or more than 3 color blocks 50 may be included. Of course, the LED post 40 may emit other colors of light, and be made of other semiconductor materials.

In one embodiment, the transparent light emitting material may be silicon dioxide, silicon nitride, or the like.

In order to further simplify the process, the material of the insulating filler 60 and the transparent material may be the same, and thus, the process of filling the transparent material in one color patch 50 and the process of filling the insulating filler 60 may be combined in one process. Therefore, the method not only realizes RGB full-color display, but also simplifies the process and reduces the production cost.

The materials of the first N-type layer 31 and the second N-type layer 32 may be the same or different, and in this embodiment, since the LED pillar array is obtained by etching an epitaxial wafer, the materials of the first N-type layer 31 and the second N-type layer 32 are the same.

In a specific embodiment, the LED pillar 40 further includes a current spreading layer 43 laminated to a side of the P-type layer 42 away from the N-type layer, and the current spreading layer 43 can improve current spreading between the LED pillar 40 and the P-electrode 80, reduce internal resistance, and improve device performance.

The LED chip structure of each of the above embodiments may be a flip chip structure, or may be a vertical chip structure, where the flip chip structure is the same side as the P electrode 80 and the N electrode 90, the vertical chip structure is different sides of the P electrode 80 and the N electrode 90, and the N electrode 90 of the vertical chip structure is disposed on the side of the first N-type layer 31 away from the LED pillar 40.

Taking the preparation of a vertical chip structure as an example, the following provides a preparation method of an LED chip structure, which comprises the following steps:

step S1: a base plate is provided, the base plate including a substrate 10, a first N-type layer 31 laminated to the substrate 10, and an LED pillar array formed on the first N-type layer 31 and composed of a plurality of LED pillars 40, the LED pillars 40 including a second N-type layer 32, an active layer 41, and a P-type layer 42 laminated in this order to the first N-type layer 31.

In this step, the LED pillars 40 may be sequentially deposited on the first N-type layer 31 by a bottom-up deposition method, or may be formed by a top-down etching method, preferably, an etching method is adopted to form an LED pillar array with a regular shape and a regular distribution, which is beneficial to uniform distribution of the LED pillars 40 in each color block 50 and can provide uniform light emitting colors.

In one embodiment, the method for preparing a substrate comprises the steps of:

step S11: an epitaxial wafer is provided, which includes a substrate 10, an N-type layer 30, an active layer 41, and a P-type layer 42, which are sequentially stacked. The epitaxial wafer may also include other functional layer structures, for example, a buffer layer 20 may be further disposed between the substrate 10 and the N-type layer 30 to reduce various defects in epitaxial growth, and a current spreading layer 43 may be further disposed outside the P-type layer 42 to improve uniformity of current spreading between the P-type layer 42 and the P-electrode 80, reduce internal resistance loss, and the like.

Referring to fig. 1, in the present embodiment, an epitaxial wafer includes a substrate 10, a buffer layer 20, an N-type layer 30 of N-GaN, an active layer 41 of InGaN/GaN blue light multi-quantum hydrazine, a P-type layer 42 of P-GaN, and a current spreading layer 43, which are sequentially stacked, the N-type layer of N-GaN, the active layer 41 of InGaN/GaN blue light multi-quantum hydrazine, and the P-type layer 42 of P-GaN constitute an epitaxial material of a blue LED.

Step S12: and forming a patterned mask layer on the P-type layer 42 of the epitaxial wafer, and etching the epitaxial wafer by using the patterned mask layer as a mask until the substrate is inside the N-type layer 30 to obtain the substrate.

In the present manufacturing method, the first N-type layer 31 and the second N-type layer 32 are made of the same material.

In the present embodiment, a hard thin film layer, which may be, for example, silicon dioxide or silicon nitride, is deposited on the upper surface of the current spreading layer 43, a patterned mask layer is prepared on the upper surface of the hard thin film layer, the hard thin film layer and the current spreading layer 43 are etched using the patterned mask layer as a mask, and then the epitaxial wafer is etched using the current spreading layer 43 as a mask until reaching the inside of the N-type layer 30, so as to obtain an LED pillar array structure including a plurality of LED pillars 40, as shown in fig. 2. The arrangement of the hard thin film layer can improve the pattern transfer accuracy to enable the nano-sized LED pillar 40 to be obtained.

Step 13: in the embodiment, the method further includes a step of passivating the side wall of the LED pillar 40, specifically, the LED pillar 40 is placed in a KOH solution of 1mol/L at 80 ℃ to be soaked for 5min to 10min, and after a side wall damage layer is removed, the LED pillar is cleaned by an HCl solution.

Step S2: referring to fig. 3, an insulating filler 60 is filled in a gap between portions of the LED pillars 40 to space different color patches 50, each color patch 50 including a plurality of LED pillars 40.

And step S3: the gaps between the LED columns 40 in each color patch 50 are filled with the corresponding light emitting materials 70.

The order of filling the insulating filler 60 and the light emitting material 70 filling each color cell 50 may be arbitrarily adjusted.

In this embodiment, the number of the color blocks 50 is 3, and the light emitting materials 70 are red quantum dot materials, green quantum dot materials, and transparent materials, respectively.

In order to optimize the manufacturing process, the transparent material is provided as the same material as the insulating filler 60, and the filling of the transparent material and the preparation of the insulating filler 60 are performed in one process.

Silicon nitride or silicon dioxide is a preferable material for the transparent material and the insulating filler 60 because it is an insulating material and also a transparent material.

In this embodiment, the red light quantum dot material, the green light quantum dot material, and the transparent material of silicon nitride or silicon dioxide are sequentially filled, and the transparent material is filled at the position of the corresponding luminescent material 70 and also at the position of the insulating filler 60.

And step S4: referring to fig. 4, a P-electrode 80 is formed, and the P-electrode 80 is electrically connected to the P-type layers 42 of all the LED pillars 40 of all the color patches 50.

Referring to fig. 4, in the present embodiment, the P-electrode 80 includes all the LED pillars 40 laminated to all the color patches 50, the insulating filler 60, and a metal layer 81 above the light emitting material 70 and a conductive substrate 82 bonded to the metal layer 81, the metal layer 81 is electrically connected to the P-type layers 42 of all the LED pillars 40 of all the color patches 50, and specifically, the forming process of the P-electrode 80 includes the following steps:

step S41: the metal layer 81 may be formed by depositing a metal layer 81 having a reflection function by electron beam evaporation, the metal layer 81 may have a single-layer structure, or may be formed by sequentially stacking two or more layers, and the material of each metal layer 81 may be Ni, ag, ti, al, au, or the like, for example, a Ni/Ag composite layer, a Ti/Al/Ti/Au composite layer, or the like.

Step S42: the conductive substrate 82 is bonded with the metal layer 81, and the conductive substrate 82 is a Si substrate or a Cu substrate, so that the chip has good heat dissipation performance and the heat dissipation performance of the chip is improved.

Step S5: referring to fig. 5, the substrate 10 is removed to expose the N-type layer.

Referring to fig. 5, in the present embodiment, the substrate 10 and the buffer layer 20 are removed to expose the N-type layer, and the substrate 10 and the buffer layer 20 may be removed by laser lift-off, mechanical polishing, chemical etching, or a combination thereof.

Step S6: referring to fig. 6, the exposed surface of the N-type layer is a light-emitting surface 33, and the light-emitting surface 33 is roughened, so that the light-emitting surface 33 forms a hexagonal cone shape, thereby reducing total reflection of light and improving light extraction efficiency.

In the embodiment, the hot KOH solution is used to roughen the N-type layer surface of the N-GaN layer, so that the light emitting surface 33 forms a hexagonal cone shape, thereby reducing total reflection of light and improving light extraction efficiency.

Step S7: referring to fig. 6, a spacer groove 34 is formed at a position of the first N-type layer 31 corresponding to the position of the insulating filler 60, and the spacer groove 34 is used to prevent the first N-type layers 31 of the respective color patches 50 from being connected to each other. The spacer grooves 34 may be fabricated by wet etching, dry etching, dicing with a dicing saw, or the like.

Step S8: referring to fig. 7, a passivation layer 35 is formed on the roughened surface and in the spacer grooves 34, and the passivation layer 35 in the spacer grooves 34 prevents the first N-type layers 31 of the color patches 50 from being electrically connected to each other.

The passivation layer 35 may be made of silicon dioxide, silicon nitride, aluminum oxide, or the like, and the passivation layer 35 may be formed by using a PECVD (plasma enhanced chemical vapor deposition) or ALD (atomic layer deposition) method.

Step S9: referring to fig. 8, the preparation of the N-electrode 90 electrically connected to the first N-type layer 31 of each color patch 50 specifically includes the steps of:

step S91: openings are made in the passivation layer 35 to expose the first N-type layer 31 for deposition of the N-electrode 90.

In this embodiment, an adhesive and an electron beam resist are sequentially spin-coated on the passivation layer 35, and the adhesive improves the bonding strength between the electron beam resist and the passivation layer 35, thereby facilitating the improvement of the lithography precision. Then, exposure and development are performed to form a patterned photoresist layer, and the passivation layer 35 is etched using the patterned photoresist layer as a mask to expose the first N-type layer 31.

Then etching is carried out by adopting an RIE (reactive ion etching) method, ar ions are utilized to bombard the N-GaN surface, the Ga-N bonds are broken, and N vacancies (donors) are formed, so that the carrier concentration in the N-GaN layer is increased, and the ohmic contact performance of the N electrode 90 is improved. Specifically, the device is placed into an RIE reaction chamber, and bombarded for 5min-10min under the power of 100W, so that the hole opening is completed.

Step S92: an N electrode 90 is formed.

The N-electrode 90 may be formed at the opening by evaporation using an electron beam evaporation technique. In this embodiment, the N electrode 90 is a Cr/Pt/Au composite layer.

The invention also discloses a display module comprising the LED chip structure or the LED chip structure prepared by the preparation method. The display module can be applied to mobile phones, flat panels, notebook computers, televisions, AR/VR equipment, vehicle instruments, central control, outdoor displays, head-up displays (HUDs) and other products.

The invention also discloses electronic equipment comprising the display module, wherein the electronic equipment can be a mobile phone, a tablet, a notebook computer, a television, AR/VR equipment, a vehicle instrument and central control, an outdoor display, a head-up display (HUD) and the like.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the claims. For example, each color block is not limited to the 4 LED pillars disclosed in the embodiments, and may be set according to actual situations, and this embodiment is not particularly limited. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. An LED chip structure is characterized by comprising a first N-type layer and an LED column array formed on the first N-type layer and composed of a plurality of LED columns, wherein each LED column comprises a second N-type layer, an active layer and a P-type layer which are sequentially laminated to the first N-type layer, the LED column array is divided into different color blocks by insulating fillers filled in gaps among partial LED columns, each color block comprises not less than 2 LED columns, and corresponding luminescent materials are filled in the gaps of the LED columns in each color block,

2. The LED chip structure of claim 1, wherein a surface of the first N-type layer facing away from the LED pillar is a light-emitting surface, the LED chip structure further comprises a passivation layer covering the light-emitting surface and filling the spacing grooves, and the passivation layer filling the spacing grooves prevents the first N-type layers of the color blocks from being electrically connected to each other.

3. The LED chip structure of claim 1, wherein the number of N electrodes is at least 1, and when the number of N electrodes is plural, the N electrodes are uniformly or symmetrically distributed.

4. The LED chip structure of claim 1, wherein the LED pillar is a blue LED pillar, the number of the color blocks is 3, and the light emitting material of each of the color blocks is a red light emitting material, a green light emitting material, and a transparent material.

5. The LED chip structure according to claim 4, wherein the material of the insulating filler is a transparent insulating filler, the material of the transparent insulating filler is silicon nitride or silicon dioxide, and the transparent material is silicon nitride or silicon dioxide;

or the insulating filler is made of opaque insulating filler or reflective insulating filler, and the transparent material is silicon nitride or silicon dioxide.

6. The LED chip structure according to any one of claims 1 to 5, wherein the LED chip structure is a flip chip structure or a vertical chip structure.

7. A preparation method of an LED chip structure is characterized by comprising the following steps:

removing the substrate to expose the first N-type layer;

and preparing an N electrode electrically connected with the first N type layer of each color block, wherein the N electrode supplies power to all the LED columns in the color blocks, so that each color block can be driven to emit light independently and electrically.

8. The manufacturing method according to claim 7, further comprising a process of forming a passivation layer on a surface of the first N-type layer facing away from the LED pillars and in the spacing grooves after the formation of the spacing grooves and before the preparation of the N-electrodes, wherein the passivation layer in the spacing grooves electrically disconnects the first N-type layers of the color blocks from each other.

9. The production method according to claim 7 or 8, further comprising a process of roughening the surface of the exposed first N-type layer after removing the substrate and before forming the spacer grooves;

after the light emitting material is filled and before the substrate is removed, a process of forming a P-electrode is further included, and the P-electrode is electrically connected with the P-type layers of all the LED columns.

10. A display module, comprising the LED chip structure according to any one of claims 1 to 6, or the LED chip structure prepared by the preparation method according to any one of claims 7 to 9.

11. An electronic device comprising the display module according to claim 10.