A micro-led micro display device without peeling of a sapphire substrate and a preparation method thereof

Abstract

The application provides a preparation method of a Micro-LED micro display device without sapphire substrate peeling, which comprises the following steps: firstly, preparing a LED micro pixel array on a sapphire wafer, a P-type gallium nitride epitaxial layer is close to the sapphire substrate, a multilayer quantum well layer is grown on the P-type gallium nitride epitaxial layer, an N-type gallium nitride epitaxial layer is grown on the multilayer quantum well, and an N-pole conductive electrode is epitaxially grown on the two side edges above the sapphire substrate; coating a color conversion layer on the sapphire wafer after the LED is grown, preparing a color filter layer above the color conversion layer after the color conversion layer is solidified to realize RGB color display; polishing the sapphire substrate, after thinning is completed, photoetching photoresist, etching the sapphire to the P-type gallium nitride layer and the N-pole conductive electrode; depositing P-pole metal and N-pole metal, and patterning to form P-pole and N-pole lead wires; cutting the sapphire wafer to cut out N small panels; and preparing the LED display device chip after flip chip bonding of the LED and a driving back plate and encapsulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices, in particular to a Micro-LED micro display device without sapphire substrate peeling and a preparation method thereof. BACKGROUND

[0002] Micro-LED display technology refers to a display technology in which microscale LEDs that naturally emit light are used as light-emitting pixel units, and the LEDs are assembled on a driving panel to form a high-density LED array. Compared with LCDs and OLEDs, Micro-LED display technology has greater advantages in brightness and resolution, contrast, energy consumption, service life, response speed, and thermal stability, etc. due to the small size, high integration, and self-emission of Micro-LED chips.

[0003] There are currently two main methods for preparing Micro-LED display devices: 1. massive transfer technology; and 2. flip-chip bonding technology + colorization technology. The first method has high LED transfer efficiency and can selectively transfer LEDs of different colors to achieve REG color display, but it is not suitable for high-resolution micro display devices. The second method is the mainstream solution for high-resolution micro devices, which typically uses the P electrode of a blue LED to flip-chip bond with a driving substrate, and the sapphire on the other side of the LED is peeled off, followed by the preparation of a color conversion layer (QD-LAYER, etc.) and finally the attachment of a CF to achieve colorization. However, this method has the following disadvantages: 1. the existing flip-chip bonding solution requires the chip to be cut into individual panel sizes, and then flip-chip bonded, which has low efficiency; 2. the existing solution has unstable sapphire peeling process, which can easily damage the functional layer of the LED and cause pixel points, resulting in poor display uniformity; and 3. the color conversion film (quantum dot film, etc.) is prepared on a small panel, which has low film formation efficiency, poor film formation process control, and poor uniformity of batch products. SUMMARY

[0004] (I) Technical problems to be solved

[0005] To solve the problems of the prior art, the present application provides a Micro-LED micro display device without sapphire substrate peeling and a preparation method thereof, which solves the problems of low efficiency and poor uniformity of the existing Micro-LED display device preparation method.

[0006] (II) Technical solutions

[0007] To achieve the above object, the present application is implemented by the following technical solutions:

[0008] A preparation method of a Micro-LED micro display device without sapphire substrate peeling, comprising:

[0009] First, a density LED micro-pixel array is prepared on a sapphire wafer, a P-type gallium nitride epitaxial layer is close to the sapphire substrate, a multilayer quantum well layer is grown on the P-type gallium nitride epitaxial layer, an N-type gallium nitride epitaxial layer is grown on the multilayer quantum well, and an N-pole conductive electrode is epitaxially grown on the two side edges above the sapphire substrate;

[0010] After the sapphire wafer on which the LED is grown is coated with a color conversion layer, a color filter layer is prepared above the color conversion layer after the color conversion layer is cured to realize RGB color display;

[0011] The sapphire substrate is polished, and after thinning is completed, the sapphire is etched to the P-type gallium nitride layer and the N-pole conductive electrode after photoresist is photoetched;

[0012] P-electrode metal and N-electrode metal are deposited, and the leads of the P-electrode and the N-electrode are patterned;

[0013] The sapphire wafer is cut, and N small panels are cut out;

[0014] After the LED is flip-chip bonded with a driving backboard and is encapsulated, the preparation of the LED display device chip is completed.

[0015] Preferably, the sapphire wafer on which the LED is grown is coated with a color conversion layer in a spin / slit manner.

[0016] Preferably, the color conversion layer can also be a patterned RGB color conversion layer.

[0017] Preferably, the color conversion layer can also be a patterned RGB color conversion layer.

[0018] Preferably, the leads of the P-electrode and the N-electrode are patterned by using a lift-off process.

[0019] The application further provides a sapphire substrate non-peeling Micro-LED micro display device prepared based on the sapphire substrate non-peeling Micro-LED micro display device preparation method.

[0020] (III) Beneficial effects

[0021] The application provides a sapphire substrate non-peeling Micro-LED micro display device and a preparation method thereof.

[0022] The technical scheme of the present application reduces the LED stripping step, reduces the preparation process difficulty, avoids the damage of sapphire stripping to the LED film layer, improves the display uniformity, avoids the LED slitting, and directly prepares the color conversion film and the color filter layer on the LED sapphire substrate wafer. After sapphire etching, metal deposition and patterning are performed, and the driving backboard is inverted bonding here, which improves the production efficiency and process stability, and optimizes the display effect. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 A sapphire substrate non-stripping Micro-LED micro display device and a preparation method flowchart thereof are provided.

[0024] Figure 2 A pixel array structure diagram of the LED display device prepared by the preparation method of the present application is shown.

[0025] Figure 3 A first type of color LED pixel array structure diagram prepared by the preparation method of the present application is shown.

[0026] Figure 4 A second type of color LED pixel array structure diagram prepared by the preparation method of the present application is shown.

[0027] Figure 5 A third type of color LED pixel array structure diagram prepared by the preparation method of the present application is shown.

[0028] Figure 6 An etched sapphire exposed P-type gallium nitride layer color LED pixel array structure diagram prepared by the preparation method of the present application is shown.

[0029] Figure 7 A color LED pixel array structure diagram with P electrode prepared by the preparation method of the present application is shown.

[0030] Figure 8 A complete color Micro-LED device structure diagram prepared by the preparation method of the present application is shown. DETAILED DESCRIPTION

[0031] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application.

[0032] As shown in Figure 1 , the present application provides a sapphire substrate non-stripping Micro-LED micro display device and a preparation method thereof, which comprises:

[0033] S1 first prepares a density LED micro-pixel array on a sapphire wafer, a P-type gallium nitride epitaxial layer is close to the sapphire substrate, a multi-layer quantum well layer is grown on the P-type gallium nitride epitaxial layer, an N-type gallium nitride epitaxial layer is grown on the multi-quantum well, and an N-pole conductive electrode is epitaxially grown on the two side edges above the sapphire substrate;

[0034] Figure 2 A pixel array structure schematic diagram of an LED display device prepared by using the preparation method of the present application;

[0035] S2 applies a color conversion layer on the sapphire wafer on which the LED is grown, and after the color conversion layer is cured, a color filter layer is prepared thereon to realize RGB color display;

[0036] Figure 3 A first type of color LED pixel array structure schematic diagram prepared by using the preparation method of the present application;

[0037] Figure 4 A second type of color LED pixel array structure schematic diagram prepared by using the preparation method of the present application;

[0038] Figure 5 A third type of color LED pixel array structure schematic diagram prepared by using the preparation method of the present application;

[0039] S3 polishes the sapphire substrate, after thinning, photoresist is etched to the P-type gallium nitride layer and the N-pole conductive electrode;

[0040] Figure 6 A color LED pixel array structure schematic diagram in which the sapphire is etched to expose the P-type gallium nitride layer prepared by using the preparation method of the present application;

[0041] S4 deposits P electrode metal and N electrode metal, and forms P electrode and N electrode leads by patterning;

[0042] Figure 7 A color LED pixel array structure schematic diagram in which the P electrode is made prepared by using the preparation method of the present application;

[0043] S5 cuts the sapphire wafer to cut out N small panels;

[0044] S6 flip-chip bonds the LED with a driving backboard and encapsulates to complete the preparation of the LED display device chip.

[0045] Preferably, the color conversion layer is applied on the sapphire wafer on which the LED is grown in a spin / slit manner.

[0046] The spin / slit mode is a slit spin coating mode, in which a slit coating head is used to feed material and the substrate rotates; the coating supply is an injection pump.

[0047] Preferably, the color conversion layer curing method can also be replaced by: depositing a passivation layer to protect the color conversion layer after curing.

[0048] Preferably, the color conversion layer can also be a patterned RGB color conversion layer.

[0049] Preferably, the lead wire for forming the P electrode and the N electrode by patterning can also use a lift-off process.

[0050] The lift-off process is a stripping process, which is an integrated circuit process and can be used to omit the etching step.

[0051] The embodiment of the present application also provides a sapphire substrate non-stripping Micro-LED micro display device, which is manufactured based on the sapphire substrate non-stripping Micro-LED micro display device manufacturing method as described above, Figure 8 A complete color Micro-LED device structure diagram prepared by using the manufacturing method of the present application is shown.

[0052] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a Micro-LED micro display device without peeling of a sapphire substrate, characterized in that, The application relates to a preparation method of a micro-LED micro display device based on a sapphire substrate. First, a density LED micro-pixel array is prepared on a sapphire wafer, a P-type gallium nitride epitaxial layer is close to a sapphire substrate, a multilayer quantum well layer is grown on the P-type gallium nitride epitaxial layer, an N-type gallium nitride epitaxial layer is grown on the multilayer quantum well, and an N-pole conductive electrode is epitaxially grown on the two side edges above the sapphire substrate; A color conversion layer is coated on the sapphire wafer after the LED is grown, a color filter layer is prepared on the color conversion layer after the color conversion layer is solidified, and RGB color display is realized; The sapphire substrate is polished, after thinning, photoresist is etched, and the sapphire is etched to the P-type gallium nitride layer and the N-pole conductive electrode; P-electrode metal and N-electrode metal are deposited, and the P-electrode and the N-electrode lead are patterned; The sapphire wafer is cut, and N small panels are cut out; The LED is flip-chip bonded with a driving back plate and is filled, and the preparation of the LED display device chip is completed.

2. The method of claim 1, wherein the method does not include a lift-off process. The color conversion layer is coated on the sapphire wafer after the LED is grown, and the coating mode is spin / slit.

3. The method of claim 1, wherein the method does not include a lift-off process. The color conversion layer is solidified, and a passivation layer is deposited to protect the color conversion layer after solidification.

4. The method of claim 1, wherein the method does not include a lift-off process. The color conversion layer is a patterned RGB color conversion layer.

5. The method of claim 4, wherein the method further comprises: The P-electrode and the N-electrode lead are patterned by using a lift-off process. 6.A Micro-LED micro display device without peeling of a sapphire substrate, characterized in that: The application is prepared based on the preparation method of the micro-LED micro display device based on the sapphire substrate.

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