WO2021115472A1 - Micro-led chip and manufacturing method therefor - Google Patents

Abstract

Disclosed are a micro-LED chip and a manufacturing method therefor. The micro-LED chip comprises: a first metal backing layer; a first LED unit attached and electrically connected to the first metal backing layer; a first planarization layer, which is attached to the first metal backing layer and exposes the side of the first LED unit away from the first metal backing layer; a second metal backing layer attached to the first planarization layer on the periphery of the first LED unit; and a second LED unit attached and electrically connected to the second metal backing layer, wherein the projection of the second LED unit on the first metal backing layer is staggered from the projection of the first LED unit on the first metal backing layer. Through the above means, each LED chip provided in the present application at least comprises first LED units and second LED units that are stacked above and below one another and are staggered from each other. The micro-LED chip is compact in size, and can improve the arrangement density of the LED units and reduce the transfer costs of the micro-LED chip.

Description

Micro-LED chip and its manufacturing method 【Technical Field】

This application relates to the field of light-emitting diodes, in particular to a Micro-LED chip and a manufacturing method thereof.

【Background technique】

Micro-LED (Micro Light Emitting Diode) is a new generation of display technology, which has higher brightness, better luminous efficiency, and lower power consumption than the existing OLED (Organic Light Emitting Diode) technology. Micro-LED technology uses thin film, miniaturization, and array design of LED structure, and its size is only about 1-50μm.

The Micro-LED chip needs to be transferred to the display substrate through a mass transfer method after manufacturing to form a display array. At present, all Micro-LED chips only include one light-emitting unit, so that after the Micro-LED chips are arranged on the display substrate, the arrangement density between the light-emitting units is relatively large. Furthermore, since each pixel of a color display requires at least three different color light-emitting units, at least three massive transfers are required to transfer the Micro-LED chips of different colors to the display substrate, and the transfer cost and error rate are high.

[Summary of the invention]

The present application provides a Micro-LED chip and a manufacturing method thereof, which can increase the arrangement density of LED units and reduce the transfer cost of the Micro-LED chip.

In order to solve the above technical problems, a technical solution adopted in this application is to provide a Micro-LED chip, the Micro-LED chip includes: a first metal backing layer; a first LED unit attached and electrically connected to the first metal On the backing layer; the first planarization layer is attached to the first metal backing layer and exposes the side of the first LED unit away from the first metal backing layer; the second metal backing layer is attached to the first metal backing layer The second LED unit is attached to and electrically connected to the second metal backing layer, wherein the projection of the second LED unit on the first metal backing layer is the same as that of the first LED unit The projections on the first metal backing layer are staggered with each other, and the first LED unit and the second LED unit are displayed in any of the three primary colors of blue, green and red.

In order to solve the above technical problems, another technical solution adopted in this application is to provide a Micro-LED chip. The Micro-LED chip includes: a first metal backing layer; a first LED unit attached and electrically connected to the first On the metal backing layer; the first planarization layer is attached to the first metal backing layer and exposes the side of the first LED unit away from the first metal backing layer; the second metal backing layer is attached to the first metal backing layer On the first planarization layer on the periphery of an LED unit; the second LED unit is attached and electrically connected to the second metal backing layer, wherein the projection of the second LED unit on the first metal backing layer is the same as that of the first LED unit The projections on the first metal backing layer are staggered from each other.

In order to solve the above technical problems, another technical solution adopted in this application is to provide a method for manufacturing a Micro-LED chip, the method comprising: providing a first epitaxial wafer and a second epitaxial wafer, wherein the first epitaxial wafer includes a first epitaxial wafer A growth substrate, a first light-emitting epitaxial layer attached to the first growth substrate, and a first metal backing layer attached and electrically connected to the side of the first light-emitting epitaxial layer away from the first growth substrate, and the second epitaxial layer The sheet includes a second growth substrate, a second light-emitting epitaxial layer attached to the second growth substrate, and a second metal backing layer attached and electrically connected to the side of the second light-emitting epitaxial layer away from the second growth substrate; Attach the side of the first metal backing layer away from the first light-emitting epitaxial layer to the transfer substrate, peel off the first growth substrate, and pattern the first light-emitting epitaxial layer to form a plurality of first LED units spaced apart from each other Form a first planarization layer on the plurality of first LED units and the first metal backing layer; attach the second metal backing layer away from the second light-emitting epitaxial layer to the first planarization layer, and peel off the first planarization layer Two growth substrates, and pattern the second light-emitting epitaxial layer to form a plurality of second LED units spaced apart from each other, wherein the projection of the second LED unit on the first metal backing layer and the first LED unit on the first metal back The projections of the underlayers are staggered from each other.

The beneficial effects of the present application are: different from the prior art, the first LED unit and the second LED unit of the present application are stacked, and the projection of the second LED unit on the first metal backing layer is similar to that of the second LED unit. The projections of the first LED units on the first metal backing layer are staggered. That is, each LED chip of the present application includes at least a first LED unit and a second LED unit that are stacked on top of each other and staggered. The size of the Micro-LED chip is compact, which can improve the arrangement density of the LED units on the metal backing layer. Reduce the manufacturing cost of Micro-LED chips. Further, by combining the different output percentages of the first LED unit and the second LED unit, the Micro-LED chip can present different colors, thereby realizing the display effect of the full-color Micro-LED chip.

【Explanation of the drawings】

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings that need to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. among them:

Fig. 1 is a schematic diagram of the structure of a Micro-LED chip according to a second embodiment of the present application;

FIG. 2 is a schematic diagram of a first top view structure of a Micro-LED chip according to the present application;

3 is a schematic diagram of a second top view structure of the Micro-LED chip according to the present application;

4 is a schematic diagram of the first process of the manufacturing method of the Micro-LED chip of the present application;

5 is a schematic diagram of the structure corresponding to each stage of the manufacturing method of the substrate shown in FIG. 4;

FIG. 6 is a schematic diagram of the second process of the manufacturing method of the Micro-LED chip of the present application;

7 is a schematic diagram of the structure corresponding to each stage of the manufacturing method of the substrate shown in FIG. 6;

FIG. 8 is a schematic diagram of the third process of the manufacturing method of the Micro-LED chip of the present application;

FIG. 9 is a schematic diagram of the structure corresponding to each stage of the manufacturing method of the substrate shown in FIG. 8.

【Detailed ways】

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

The Micro-LED chip 10 according to the first embodiment of the present application includes: a first metal backing layer 11, a first LED unit 12, a first planarization layer 13, a second metal backing layer 21, and a second LED unit 22.

Among them, the first LED unit 12 and the second LED unit 22 can display any light color among the three primary colors of blue, green and red. The first LED unit 12 and the second LED unit 22 can be the same color or different colors. limited. Further, through the superposition of the two-color light of the first LED unit 12 and the second LED unit 22, the Micro-LED chip 10 can generate multi-color linear light, the main colors are blue, cyan, dark green, green, yellow, and orange. He Hong, etc., are not limited here.

Wherein, the first LED unit 12 is attached and electrically connected to the first metal backing layer 11, and the first planarization layer 13 is attached to the first metal backing layer 11, and makes the first LED unit 12 away from the first metal backing layer 11 One side of the lining layer 11 is exposed. The second metal backing layer 21 is attached to the first planarization layer 13 on the periphery of the first LED unit 12. The second LED unit 22 is attached and electrically connected to the second metal backing layer 21.

The projection of the second LED unit 22 on the first metal backing layer 11 and the projection of the first LED unit 12 on the first metal backing layer 11 are staggered from each other.

As further shown in FIG. 1, the Micro-LED chip 10 according to the second embodiment of the present application further includes: a second planarization layer 23, a third metal backing layer 31 and a third LED unit 32.

It can be understood that Fig. 1 is only a conventional example. When the required function of the Micro-LED chip 10 is relatively single, the Micro-LED chip 10 only includes the first LED unit 12, the second LED unit 22, and the corresponding planarization layer and metal backing layer. When the required functions of the Micro-LED chip 10 are more comprehensive, the Micro-LED chip 10 also includes a fourth LED unit, a fifth LED unit or more LED units, and a corresponding planarization layer and a metal backing layer. The multiple projections on the first metal backing layer 11 corresponding to the multiple LED units are staggered.

Referring to FIGS. 2-3, further, the third LED unit 32 can display any light color among the three primary colors of blue, green and red. The third LED unit 32 can be the same color as the first LED unit 12 and the second LED unit 22, or Different colors are not limited here.

Further, through the superposition of the three-color light of the first LED unit 12, the second LED unit 22, and the third LED unit 32, the Micro-LED chip 10 can produce multi-color line light, the main colors are blue, cyan, and dark green. , Green, yellow, orange and red, etc., are not limited here.

The materials of the first metal backing layer 11, the second metal backing layer 21, and the third metal backing layer 31 are semiconductors or metals with good electrical and thermal conductivity, for example, the first metal backing layer 11 and the second metal backing layer The material of the liner layer 21 and the third metal backing layer 31 may be at least one of In, Cu, Au, Ni, Ti, Sn or an alloy thereof, which is not limited herein. The functions of the first metal backing layer 11, the second metal backing layer 21, and the third metal backing layer 31 are to form an effective support for the first LED unit 12, the second LED unit 22, and the third LED unit 32. As a conductive member, power is supplied to the first LED unit 12, the second LED unit 22, and the third LED unit 32. Further, the first metal backing layer 11, the second metal backing layer 21, and the third metal backing layer 31 can also be used as metal bonding layers to improve the first LED unit 12, the second LED unit 22, and the third LED unit 32. The adhesion strength.

The material of the first planarization layer 13 and the second planarization layer 23 can be at least one of SoG (Spin-on-Glass), RDL, BCB, and Photoresist, which are not limited here. .

The second planarization layer 23 is attached to the second metal backing layer 21 and makes the side of the second LED unit 22 away from the first metal backing layer 11 exposed. The third metal backing layer 31 is attached to the second planarization layer 23 on the periphery of the second LED unit 22. The third LED unit 32 is attached and electrically connected to the third metal backing layer 31.

The projection of the third LED unit 32 on the first metal backing layer 11 is the same as the projection of the first LED unit 12 on the first metal backing layer 11 and the projection of the second LED unit 22 on the first metal backing layer 11, respectively. The projections are staggered from each other.

The first planarization layer 13 and the second planarization layer 23 are provided with a first through hole 130 and a second through hole 230, respectively. The first planarization layer 13 may be provided with a plurality of first through holes 130 spaced apart from each other, and the arrangement of the plurality of first through holes 130 may be regular or irregularly distributed. The second planarization layer 23 may be provided with a plurality of second through holes 230 spaced apart from each other, and the arrangement of the plurality of second through holes 230 may be regular or irregularly distributed. The projection of the first through hole 130 on the first metal backing layer 11 and the projection of the second through hole 230 on the first metal backing layer 11 are staggered from each other.

Wherein, the Micro-LED chip 10 further includes: a first conductive body 14 and a second conductive body 24 arranged in the first through hole 130 and the second through hole 230.

The material of the first conductive body 14 and the second conductive body 24 may be at least one of metals such as Cu, Ti, Ni, Al, W, Pt, Au, etc., which is not limited herein.

Both ends of the first conductive body 14 respectively contact the first metal backing layer 11 and the second metal backing layer 21, and then electrically connect the first LED unit 12 and the second LED unit 22 toward one of the first metal backing layer 11 side. Both ends of the second conductor 24 respectively contact the second metal backing layer 21 and the third metal backing layer 31, and then electrically connect the second LED unit 22 and the third unit LED unit facing one of the first metal backing layer 11 side.

Among them, the Micro-LED chip 10 further includes: a first reflector 15, a second reflector 25 and a third reflector 35.

The first reflector 15 is provided between the first LED unit 12 and the first metal backing layer 11, the second reflector 25 is provided between the second LED unit 22 and the second metal backing layer 21, and the third reflector The mirror 35 is disposed between the third LED unit 32 and the third metal backing layer 31.

The first reflector 15, the second reflector 25, and the third reflector 35 can be made of transparent conductive materials for ohmic contact, such as indium tin oxide (ITO), and other metal reflectors or DBR reflectors are plated on the ITO. In other embodiments, the first reflector 15, the second reflector 25, and the third reflector 35 may have the functions of a reflector and ohmic contact at the same time, such as including silver (Ag), aluminum (Al), and nickel (Ni). , Chromium (Cr), platinum (Pt) or other suitable metal metal layer.

Wherein, the Micro-LED chip 10 further includes a first metal bonding layer 16 and a second metal bonding layer 26, and the first metal bonding layer 16 is disposed between the first planarization layer 13 and the second metal backing layer 21 , The second metal bonding layer 26 is disposed between the second planarization layer 23 and the third metal backing layer 31.

The material of the first metal bonding layer 16 and the second metal bonding layer 26 may be at least one of In, Cu, Au, Ni, Ti, Sn or an alloy thereof, which is not limited herein.

Wherein, the Micro-LED chip 10 further includes a first insulating layer 17, a second insulating layer 27 and a third insulating layer 37.

The first insulating layer 17, the second insulating layer 27, and the third insulating layer 37 can be made of at least aluminum nitride, silicon dioxide, silicon nitride, aluminum oxide, Bragg reflective layer DBR, silica gel, resin, or acrylic. One type of production, not limited here.

The above-mentioned first insulating layer 17 covers the periphery of the first LED unit 12 and exposes the side of the first LED unit 12 away from the first metal backing layer 11, and the second insulating layer 27 covers the second LED unit 22 The periphery of the second LED unit 22 is exposed away from the side of the first metal backing layer 11, and the third insulating layer 37 covers the periphery of the third LED unit 32 and keeps the third LED unit 32 away from the first metal backing layer. One side of 11 is exposed.

It should be noted that the side of the first LED unit 12 away from the first metal backing layer 11 is exposed, that is, the first exposed surface 18. The side of the second LED unit 22 away from the first metal backing layer 11 is exposed, that is, the second exposed surface 28. The side of the third LED unit 32 away from the first metal backing layer 11 is exposed, that is, the third exposed surface 38.

The first exposed surface 18, the second exposed surface 28, and the third exposed surface 38 can be respectively manufactured by printing and electroplating techniques to form a first pad (not shown) and a second pad (not shown) that are insulated from each other. Out) and a third pad (not shown in the figure), wherein the first pad is electrically connected to the first LED unit 12 by directly contacting the first LED unit 12, and the second pad is electrically connected to the first LED unit 12 by directly contacting the second LED unit 22 To be electrically connected to the second LED unit 22, the third pad is electrically connected to the third LED unit 32 by directly contacting the third LED unit 32.

Different from the prior art, the first LED unit 12 and the second LED unit 22 in the embodiment of the present application are stacked, and the projection of the second LED unit 22 on the first metal backing layer 11 is consistent with the projection of the second LED unit 22 on the first metal backing layer 11. The projections of the first LED unit 12 on the first metal backing layer 11 are staggered. That is, each LED chip of the present application includes at least a first LED unit 12 and a second LED unit 22 that are stacked on top of each other and staggered. The size of the Micro-LED chip 10 is compact, which can improve the arrangement of LED units on the metal backing layer. The cloth density reduces the manufacturing cost of the Micro-LED chip 10. Further, by combining the different output percentages of the first LED unit 12 and the second LED unit 22, the Micro-LED chip 10 can present different colors, thereby improving the display effect of the Micro-LED chip 10.

As shown in FIGS. 4 and 5, the present application also proposes a method for manufacturing the Micro-LED chip 10, which is used to manufacture the Micro-LED chip 10 in the above-mentioned embodiment. The method includes the following steps:

S101: Provide a first epitaxial wafer 100 and a second epitaxial wafer 200.

Wherein, the first epitaxial wafer 100 includes a first growth substrate 110, a first light emitting epitaxial layer 120, and a first metal backing layer 11, and the second epitaxial wafer 200 includes a second growth substrate 210, a second light emitting epitaxial layer 220, and The second metal backing layer 21.

The first light-emitting epitaxial layer 120 is attached to the first growth substrate 110, and the first metal backing layer 11 is attached and electrically connected to the side of the first light-emitting epitaxial layer 120 away from the first growth substrate 110.

The second light-emitting epitaxial layer 220 is attached to the second growth substrate 210, and the second metal backing layer 21 is attached and electrically connected to the side of the second light-emitting epitaxial layer 220 away from the second growth substrate 210.

The material of the first growth substrate 110 and the second growth substrate 210 may be at least one of sapphire, silicon, silicon carbide, gallium nitride, and gallium arsenide, which is not limited herein.

Taking the InGaN/GaN LED unit as an example, the above-mentioned first light-emitting epitaxial layer 120 may have a multilayer structure. Specifically, the MOCVD method may be used to sequentially grow the first conductive type semiconductor layer 121 and the quantum well layer on the side of the first growth substrate 110. 122. The second conductivity type semiconductor layer 123.

Specifically, the first conductive type semiconductor layer 121 is grown on the side of the first growth substrate 110. The first conductive type semiconductor layer 121 may be an n-type GaN layer, such as GaN doped with at least one of Si, Ge, and Sn. Floor. Next, a quantum well layer 122 is grown on the first conductive type semiconductor layer 121. The quantum well layer 122 can have any of the following structures: single-layer quantum well (SQW) and InGaN/GaN multilayer quantum well (MQW). Then, a second conductive type semiconductor layer 123 is grown on the quantum well layer 122. The second conductive type semiconductor layer 123 is a p-type GaN layer, such as GaN doped with at least one of Mg, Zn, Be, Ca, Sr, and Ba. Floor. In this way, the first light-emitting epitaxial layer 120 is completed. The manufacturing method of the second light-emitting epitaxial layer 220 is the same as that of the first light-emitting epitaxial layer 120, and will not be repeated here.

Further, it is also possible to grow a layer of mirror on the second conductivity type semiconductor layer 123 by using electron beam evaporation or magnetron sputtering. Transparent conductive materials can be used for ohmic contact, such as indium tin oxide (ITO), and other metal mirrors or DBR mirrors are plated on the ITO. In other embodiments, the reflector may have the function of reflector and ohmic contact at the same time, such as including silver (Ag), aluminum (Al), nickel (Ni), chromium (Cr), platinum (Pt), or other suitable metals Metal mirror layer.

S102: Attach the side of the first metal backing layer 11 away from the first light-emitting epitaxial layer 120 to the transfer substrate 40, peel off the first growth substrate 110, and pattern the first light-emitting epitaxial layer 120 to form spaced apart的Multiple first LED units12.

The material of the above-mentioned transfer substrate 40 may specifically include sapphire, silicon wafer, temporary bonding substrate, etc., which is not limited herein.

The first growth substrate 110 may be peeled off by dry etching, wet etching, laser lift-off or other suitable techniques. For example, the first growth substrate 110 is etched with a specific etchant to peel off the first growth substrate 110.

The above-mentioned patterning process may use a suitable patterning technique to form a plurality of first LED units 12 spaced apart from each other, for example, dry etching, wet etching or other suitable techniques.

Specifically, the first conductive type semiconductor layer 121, the quantum well layer 122, and the second conductive type semiconductor layer 123 may be patterned once to form a plurality of mesa structures. The above-mentioned etching process may include dry etching, wet etching, or a combination thereof. The etching process may include various etching steps, and each step is designed to use a specific etchant to effectively remove the corresponding light-emitting epitaxial layer.

In an alternative embodiment, a hard mask may be further used to form the first channel through the following processes: forming a hard mask on the second conductivity type semiconductor layer 123, patterning the hard mask using a photolithography process, and using a pattern The modified hard mask serves as an etching mask to etch the light-emitting epitaxial layer to form a first channel. In this way, a plurality of first LED units 12 spaced apart from each other are formed.

It is worth noting that in this application, although the flip-chip structure LED is described as an example, this application is also applicable to manufacturing vertical structure LEDs and front-mounted structure LEDs.

S103: forming a first planarization layer 13 on the plurality of first LED units 12 and the first metal backing layer 11.

S104: Attach the side of the second metal backing layer 21 away from the second light-emitting epitaxial layer 220 to the first planarization layer 13, peel off the second growth substrate 210, and pattern the second light-emitting epitaxial layer 220 to form each other A plurality of second LED units 22 are arranged at intervals.

Wherein, the second growth substrate 210 may be peeled off by dry etching, wet etching, laser lift-off or other suitable techniques. For example, the second growth substrate 210 is etched with a specific etchant to peel off the second growth substrate 210.

The structure of the second LED unit 22 is the same as the structure of the first LED unit 12, and the manufacturing method of the second LED unit 22 is the same as the manufacturing method of the first LED unit 12. For details, please refer to the above-mentioned embodiment, which will not be repeated here.

The projection of the second LED unit 22 on the first metal backing layer 11 and the projection of the first LED unit 12 on the first metal backing layer 11 are staggered from each other. That is, the LED chip of the embodiment of the present application includes a first LED unit 12 and a second LED unit 22 that are stacked on top of each other and staggered. The size of the Micro-LED chip 10 is compact, which can improve the arrangement of the LED units on the metal backing layer. Density reduces the manufacturing cost of the Micro-LED chip 10. Further, by combining the different output percentages of the first LED unit 12 and the second LED unit 22, the Micro-LED chip 10 can present different colors, thereby improving the display effect of the Micro-LED chip 10.

As shown in Figure 6 and Figure 7, the method further includes the following steps:

S105: forming a second planarization layer 23 on the plurality of second LED units 22 and the second metal backing layer 21.

S106: Provide a third epitaxial wafer 300.

The third epitaxial wafer 300 includes a third growth substrate 310, a third light emitting epitaxial layer 320 attached to the third growth substrate 310, and a third light emitting epitaxial layer 320 attached and electrically connected to the third light emitting epitaxial layer 320 away from the third growth substrate 310. The third metal backing layer 31 on one side.

S107: Attach a side of the third metal backing layer 31 away from the third light-emitting epitaxial layer 320 to the second planarization layer 23, peel off the third growth substrate 310, and pattern the third light-emitting epitaxial layer 320 to form each other A plurality of third LED units 32 are arranged at intervals.

The structure of the third LED unit 32 is the same as the structure of the first LED unit 12, and the manufacturing method of the third LED unit 32 is the same as the manufacturing method of the first LED unit 12. For details, please refer to the above-mentioned embodiment, which will not be repeated here.

The projection of the third LED unit 32 on the first metal backing layer 11 is the same as the projection of the first LED unit 12 on the first metal backing layer 11 and the projection of the second LED unit 22 on the first metal backing layer 11 respectively. The projections on are staggered from each other. That is, the LED chip of the embodiment of the present application includes a first LED unit 12, a second LED unit 22, and a third LED unit 32 stacked on top of each other and staggered. The size of the Micro-LED chip 10 is compact, which can improve the LED unit on the metal back The arrangement density on the lining layer reduces the manufacturing cost of the Micro-LED chip 10. Further, by combining the different output percentages of the first LED unit 12, the second LED unit 22, and the third LED unit 32, the Micro-LED chip 10 can present different colors, thereby improving the display of the Micro-LED chip 10 effect.

The material of the third growth substrate 310 may be at least one of sapphire, silicon, silicon carbide, gallium nitride, and gallium arsenide, which is not limited herein.

Wherein, the second growth substrate 210 may be peeled off by dry etching, wet etching, laser lift-off or other suitable techniques. For example, the third growth substrate 310 is etched with a specific etchant to peel off the third growth substrate 310.

The first epitaxial wafer 100 further includes a first reflector 15 located between the first light-emitting epitaxial layer 120 and the first metal backing layer 11 and corresponding to the position of the first LED unit 12. The second epitaxial wafer 200 further includes a second reflector 25 located between the second light-emitting epitaxial layer 220 and the second metal backing layer 21 and corresponding to the position of the second LED unit 22. The third epitaxial wafer 300 further includes a third reflector 35 located between the third light emitting epitaxial layer 320 and the third metal backing layer 31 and corresponding to the position of the third LED unit 32.

The first reflector 15, the second reflector 25, and the third reflector 35 can be made of transparent conductive materials for ohmic contact, such as indium tin oxide (ITO), and other metal reflectors or DBR reflectors are plated on the ITO. In other embodiments, the reflector may have the function of reflector and ohmic contact at the same time, such as including silver (Ag), aluminum (Al), nickel (Ni), chromium (Cr), platinum (Pt), or other suitable metals Metal mirror layer.

As shown in Figures 8 and 9, the method further includes the following steps:

S108: Pattern the third metal backing layer 31, the second planarization layer 23, the second metal backing layer 21, and the first planarization layer 13, so that the first LED unit 12 and the second LED unit 22 are far away from the first One side of the metal backing layer 11 is exposed.

S109: Pattern the first metal backing layer 11 to form a plurality of independent Micro-LED chips 10, wherein each Micro-LED chip 10 includes at least one first LED unit 12, at least one second LED unit 22, and At least one third LED unit 32.

Further, before step S103, the method further includes the following step: covering the first LED unit 12 with the first insulating layer 17. Before step S105, the method further includes the following step: covering the second LED unit 22 with the second insulating layer 27. Before step S108, the method further includes the following step: covering the third LED unit 32 with the third insulating layer 37.

Specifically, the outer surfaces of the first LED unit 12, the second LED unit 22, and the third LED unit 32 are respectively covered with the first insulating layer 17, the second insulating layer 27, and The third insulating layer 37, the first insulating layer 17, the second insulating layer 27, and the third insulating layer 37 can be made of aluminum nitride, silicon dioxide, silicon nitride, aluminum oxide, Bragg reflective layer DBR, silica gel, and resin. Or made of acrylic.

Further, step S108 further includes: patterning the first insulating layer 17, the second insulating layer 27, and the third insulating layer 37 to expose the first LED unit 12, the second LED unit 22, and the third LED unit 32, respectively. The side away from the first metal backing layer 11.

It should be noted that the side of the first LED unit 12 away from the first metal backing layer 11 is exposed, that is, the first exposed surface 18. The side of the second LED unit 22 away from the first metal backing layer 11 is exposed, that is, the second exposed surface 28. The side of the third LED unit 32 away from the first metal backing layer 11 is exposed, that is, the third exposed surface 38.

The first exposed surface 18, the second exposed surface 28, and the third exposed surface 38 can be insulated from each other by coating techniques such as printing, electroplating, thermal evaporation, electron beam evaporation, or magnetron sputtering. The pad, the second pad and the third pad, wherein the first pad is electrically connected to the first LED unit 12 by directly contacting the first LED unit 12, and the second pad is electrically connected to the first LED unit 12 by directly contacting the second LED unit 22 The second LED unit 22 is electrically connected, and the third pad is electrically connected with the third LED unit 32 by directly contacting the third LED unit 32.

Further, before step S104, the method further includes the following steps: forming a first through hole 130 on the first planarization layer 13, and forming a first conductive body 14 in the first through hole 130, so that After the two metal backing layers 21 are attached to the first planarization layer 13, the two ends of the first conductor 14 respectively contact the first metal backing layer 11 and the second metal backing layer 21, thereby electrically connecting the first LED unit 12 And the second LED unit 22 faces one side of the first metal backing layer 11.

Further, before step S107, the method further includes the following steps: forming a second through hole 230 on the second planarization layer 23, and forming a second electrical conductor 24 in the second through hole 230, so that the third After the metal backing layer 31 is attached to the second planarization layer 23, the two ends of the second conductor 24 respectively contact the second metal backing layer 21 and the third metal backing layer 31, thereby electrically connecting the second LED unit 22 and The third unit LED unit faces the side of the first metal backing layer 11.

Further, before step S102, the method further includes the following steps: forming a first metal bonding layer 16 on the transfer substrate 40, and patterning the transfer substrate 40 and the first metal bonding layer 16 to form a plurality of substrates. The bottom bump 401 and the first metal bonding pattern 161 formed on the top of the substrate bump 401. The first metal backing layer 11 is bonded to the first metal bonding pattern 161.

Wherein, the first metal bonding layer 16 can be formed on the transfer substrate 40 by methods such as thermal evaporation, electron beam evaporation, and magnetron sputtering evaporation. The material of the first metal bonding layer 16 may be at least one of In, Cu, Au, Ni, Ti, Sn or an alloy thereof, which is not limited herein.

The above-mentioned patterning process may use a suitable patterning technique to form a plurality of substrate protrusions 401 and the first metal bonding pattern 161 formed on the top of the substrate protrusions 401, for example, dry etching, wet etching, laser lift-off or Other suitable technologies. For example, a mask is covered on the transfer substrate 40 and the first metal bonding layer 16. The transfer substrate 40 and the first metal bonding layer 16 at positions not covered by the mask are removed by etching technology to form a plurality of substrate protrusions 401 and a first metal bonding pattern 161 formed on the top of the substrate protrusions 401.

Before step S104, the method further includes the following steps: forming a second metal bonding layer 26 on the first planarization layer 13. The second metal backing layer 21 is bonded to the second metal bonding layer 26.

Before step S107, the method further includes the following steps: forming a third metal bonding layer 36 on the second planarization layer 23, wherein the third metal backing layer 31 is bonded to the third metal bonding layer 36.

Specifically, the second metal bonding layer 26 can be formed on the first planarization layer 13 by methods such as thermal evaporation, electron beam evaporation, and magnetron sputtering evaporation. Thermal evaporation, electron beam evaporation, and The third metal bonding layer 36 is formed on the second planarization layer 23 by methods such as magnetron sputtering and evaporation. The material of the second metal bonding layer 26 and the third metal bonding layer 36 may be at least one of In, Cu, Au, Ni, Ti, Sn or an alloy thereof, which is not limited herein.

Different from the state of the art, the first LED unit 12 and the second LED unit 22 of the embodiment of the present application are stacked and arranged, and the projection of the second LED unit 22 on the first metal backing layer 11 is consistent with the projection of the second LED unit 22 on the first metal backing layer 11. The projections of the first LED unit 12 on the first metal backing layer 11 are staggered. That is, each LED chip of the present application includes at least a first LED unit 12 and a second LED unit 22 that are stacked on top of each other and staggered. The size of the Micro-LED chip 10 is compact, which can improve the arrangement of LED units on the metal backing layer. The cloth density reduces the manufacturing cost of the Micro-LED chip 10. Further, by combining the different output percentages of the first LED unit 12 and the second LED unit 22, the Micro-LED chip 10 can present different colors, thereby improving the display effect of the Micro-LED chip 10.

The above are only implementations of this application, and do not limit the scope of this application. Any equivalent structure or equivalent process transformation made using the content of the description and drawings of this application, or directly or indirectly applied to other related technical fields, The same reasoning is included in the scope of patent protection of this application.

Claims (19)

A Micro-LED chip, wherein the Micro-LED chip includes: The first metal backing layer; The first LED unit is attached and electrically connected to the first metal backing layer; The first planarization layer is attached to the first metal backing layer and exposes the side of the first LED unit away from the first metal backing layer; A second metal backing layer attached to the first planarization layer on the periphery of the first LED unit; The second LED unit is attached and electrically connected to the second metal backing layer, wherein the projection of the second LED unit on the first metal backing layer is the same as that of the first LED unit on the first metal backing layer. The projections on a metal backing layer are staggered with each other; The first LED unit and the second LED unit are displayed in any light color among the three primary colors of blue, green and red. The Micro-LED chip according to claim 1, wherein the Micro-LED chip further comprises: The second planarization layer is attached to the second metal backing layer and exposes the side of the second LED unit away from the first metal backing layer; A third metal backing layer attached to the second planarization layer on the periphery of the second LED unit; The third LED unit is attached and electrically connected to the third metal backing layer, wherein the projection of the third LED unit on the first metal backing layer is the same as that of the first LED unit on the The projection on the first metal backing layer and the projection of the second LED unit on the first metal backing layer are staggered from each other. The Micro-LED chip according to claim 2, wherein the first planarization layer and the second planarization layer are respectively provided with a first through hole and a second through hole, and the Micro-LED chip further comprises The first conductive body and the second conductive body in the first through hole and the second through hole, both ends of the first conductive body are in contact with the first metal backing layer and the second metal backing, respectively Layer, and then electrically connect the first LED unit and the second LED unit toward the side of the first metal backing layer, and both ends of the second conductive body are in contact with the second metal backing layer, respectively And the third metal backing layer, thereby electrically connecting the second LED unit and the third unit LED unit toward the side of the first metal backing layer. The Micro-LED chip according to claim 2, wherein the Micro-LED chip further comprises a first reflector arranged between the first LED unit and the first metal backing layer, and A second reflector between the second LED unit and the second metal backing layer, and a third reflector disposed between the third LED unit and the third metal backing layer. The Micro-LED chip according to claim 2, wherein the Micro-LED chip further comprises a second planarization layer disposed between the first planarization layer and the second metal backing layer, and the second planarization layer, respectively. Two metal bonding layers between the layer and the third metal backing layer. The Micro-LED chip according to claim 2, wherein the Micro-LED chip further comprises a cladding on the periphery of the first LED unit and keeping the first LED unit away from the first metal backing layer A first insulating layer exposed on one side of the second LED unit, a second insulating layer exposed on the side of the second LED unit that is away from the first metal backing layer and covering the periphery of the second LED unit A third insulating layer is exposed on the periphery of the third LED unit and makes the third LED unit away from the first metal backing layer. A Micro-LED chip, wherein the Micro-LED chip includes: The first metal backing layer; The first LED unit is attached and electrically connected to the first metal backing layer; The first planarization layer is attached to the first metal backing layer and exposes the side of the first LED unit away from the first metal backing layer; A second metal backing layer attached to the first planarization layer on the periphery of the first LED unit; The second LED unit is attached and electrically connected to the second metal backing layer, wherein the projection of the second LED unit on the first metal backing layer is the same as that of the first LED unit on the first metal backing layer. The projections on a metal backing layer are staggered from each other. The Micro-LED chip according to claim 7, wherein the Micro-LED chip further comprises: The second planarization layer is attached to the second metal backing layer and exposes the side of the second LED unit away from the first metal backing layer; A third metal backing layer attached to the second planarization layer on the periphery of the second LED unit; The third LED unit is attached and electrically connected to the third metal backing layer, wherein the projection of the third LED unit on the first metal backing layer is the same as that of the first LED unit on the The projection on the first metal backing layer and the projection of the second LED unit on the first metal backing layer are staggered from each other. The Micro-LED chip according to claim 8, wherein the first planarization layer and the second planarization layer are respectively provided with a first through hole and a second through hole, and the Micro-LED chip further comprises The first conductive body and the second conductive body in the first through hole and the second through hole, both ends of the first conductive body are in contact with the first metal backing layer and the second metal backing, respectively Layer, and then electrically connect the first LED unit and the second LED unit toward the side of the first metal backing layer, and both ends of the second conductive body are in contact with the second metal backing layer, respectively And the third metal backing layer, thereby electrically connecting the second LED unit and the third unit LED unit toward the side of the first metal backing layer. The Micro-LED chip according to claim 8, wherein the Micro-LED chip further comprises a first reflector disposed between the first LED unit and the first metal backing layer, and A second reflector between the second LED unit and the second metal backing layer, and a third reflector disposed between the third LED unit and the third metal backing layer. The Micro-LED chip according to claim 8, wherein the Micro-LED chip further comprises the second planarization layer and the second metal backing layer respectively disposed between the second planarization layer and the second planarization layer. Two metal bonding layers between the layer and the third metal backing layer. 8. The Micro-LED chip according to claim 8, wherein the Micro-LED chip further comprises a periphery of the first LED unit and keeps the first LED unit away from the first metal backing layer A first insulating layer exposed on one side of the second LED unit, a second insulating layer exposed on the side of the second LED unit that is away from the first metal backing layer and covering the periphery of the second LED unit A third insulating layer that is exposed on the periphery of the third LED unit and makes the third LED unit away from the first metal backing layer. A method for manufacturing a Micro-LED chip, wherein the method includes: A first epitaxial wafer and a second epitaxial wafer are provided, wherein the first epitaxial wafer includes a first growth substrate, a first light-emitting epitaxial layer attached to the first growth substrate, and attached and electrically connected to the first growth substrate. A first metal backing layer on a side of a light-emitting epitaxial layer away from the first growth substrate. The second epitaxial wafer includes a second growth substrate and a second light-emitting layer attached to the second growth substrate. An epitaxial layer and a second metal backing layer attached and electrically connected to a side of the second light-emitting epitaxial layer away from the second growth substrate; Attach the side of the first metal backing layer away from the first light-emitting epitaxial layer to a transfer substrate, peel off the first growth substrate, and pattern the first light-emitting epitaxial layer to form a gap between each other A plurality of first LED units provided; Forming a first planarization layer on the plurality of first LED units and the first metal backing layer; Attach the side of the second metal backing layer away from the second light-emitting epitaxial layer to the first planarization layer, peel off the second growth substrate, and pattern the second light-emitting epitaxial layer To form a plurality of second LED units spaced apart from each other, wherein the projection of the second LED unit on the first metal backing layer and the projection of the first LED unit on the first metal backing layer are mutually stagger. The method according to claim 13, wherein the method further comprises: Forming a second planarization layer on the plurality of second LED units and the second metal backing layer; A third epitaxial wafer is provided, wherein the third epitaxial wafer includes a third growth substrate, a third light-emitting epitaxial layer attached to the third growth substrate, and a third light-emitting epitaxial layer attached and electrically connected to the third light-emitting epitaxial layer away from A third metal backing layer on one side of the third growth substrate; Attach the side of the third metal backing layer away from the third light-emitting epitaxial layer to the second planarization layer, peel off the third growth substrate, and pattern the third light-emitting epitaxial layer To form a plurality of third LED units spaced apart from each other, wherein the projection of the third LED unit on the first metal backing layer is the same as that of the first LED unit on the first metal backing layer. The projection of and the projection of the second LED unit on the first metal backing layer are staggered with each other. The method according to claim 14, wherein the method further comprises: The third metal backing layer, the second planarization layer, the second metal backing layer, and the first planarization layer are patterned so that the first LED unit and the second LED The side of the unit away from the first metal backing layer is exposed; The first metal backing layer is patterned to form a plurality of independent Micro-LED chips, wherein each Micro-LED chip includes at least one of the first LED unit, at least one of the second LED unit, and at least 1. The third LED unit. 15. The method of claim 15, wherein before the step of forming a first planarization layer on the plurality of first LED units and the first metal backing layer, further comprising: using a first insulating layer Covering the first LED unit; Before the step of forming a second planarization layer on the plurality of second LED units and the second metal backing layer, the method further includes: covering the second LED unit with a second insulating layer; Before the step of patterning the third metal backing layer, the second planarization layer, the second metal backing layer, and the first planarization layer, the method further includes: wrapping with a third insulating layer Covering the third LED unit; The step of patterning the third metal backing layer, the second planarization layer, the second metal backing layer, and the first planarization layer further includes: The first insulating layer, the second insulating layer and the first insulating layer are patterned to respectively expose one of the first LED unit, the second LED unit, and the third LED unit away from the first metal backing layer. side. 14. The method of claim 14, wherein before the step of attaching the second metal backing layer to the first planarization layer on the side of the second metal backing layer away from the second light-emitting epitaxial layer, the method further comprises: A first through hole is formed on the first planarization layer, and a first electrical conductor is formed in the first through hole, so that the second metal backing layer is attached to the first planarization layer After that, both ends of the first conductive body respectively contact the first metal backing layer and the second metal backing layer, and then electrically connect the first LED unit and the second LED unit toward the One side of the first metal backing layer; Before the step of attaching the third metal backing layer away from the third light-emitting epitaxial layer to the second planarization layer, the method further includes: A second through hole is formed on the second planarization layer, and a second electrical conductor is formed in the second through hole, so that the third metal backing layer is attached to the second planarization layer After that, both ends of the second conductive body respectively contact the second metal backing layer and the third metal backing layer, and then electrically connect the second LED unit and the third unit LED unit facing all the way. Said one side of the first metal backing layer. 15. The method according to claim 14, wherein before the step of attaching the side of the first metal backing layer away from the first light-emitting epitaxial layer to the transfer substrate, the method further comprises: Forming a first metal bonding layer on the transfer substrate; The transfer substrate and the first metal bonding layer are patterned to form a plurality of substrate protrusions and a first metal bonding pattern formed on the top of the substrate protrusions; wherein the first metal backing layer Bonding to the first metal bonding pattern; Before the step of attaching the side of the second metal backing layer away from the second light-emitting epitaxial layer to the first planarization layer, the method further includes: Forming a second metal bonding layer on the first planarization layer, wherein the second metal backing layer is bonded to the second metal bonding layer; Before the step of attaching the third metal backing layer away from the third light-emitting epitaxial layer to the second planarization layer, the method further includes: A third metal bonding layer is formed on the second planarization layer, wherein the third metal backing layer is bonded to the third metal bonding layer. The method according to claim 14, wherein the first epitaxial wafers respectively comprise a first epitaxial wafer located between the first light emitting epitaxial layer and the first metal backing layer and corresponding to the position of the first LED unit. A reflector, the second epitaxial wafer further includes a second reflector located between the second light-emitting epitaxial layer and the second metal backing layer and corresponding to the position of the second LED unit, the The third epitaxial wafer further includes a third reflector located between the third light emitting epitaxial layer and the third metal backing layer and corresponding to the position of the third LED unit.

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