A method for bonding and transferring Micro-LED arrays on silicon substrates protected by AlN thin films

Abstract

The present invention discloses a method for bonding and transferring a Micro-LED array on a silicon substrate using an AlN thin film. The surface of the Micro-LED array has a protective AlN thin film, which protects the driving substrate from being damaged during the bonding and transfer between the Micro-LED array and the driving substrate and the removal of the silicon substrate. The present invention has the following characteristics: 1. The AlN thin film can achieve a good selective protection effect; 2. The AlN thin film as a protective layer can completely fill the gaps between the Micro-LED arrays, and can achieve maximum protection of the bonding metal layer and metal pads on the surface of the driving substrate. During the dry etching process to remove the silicon substrate, the adhesion and accumulation of etching products can be well avoided and reduced, thereby providing a relatively clean bonding metal surface for subsequent multiple bonding transfers of Micro-LEDs; 3. Due to the good selective protection effect on the unbonded area of ​​the driving substrate, if sufficient gaps are left on the Micro-LED array, multiple bonding is allowed, thereby enabling the preparation of dual-color or even multi-color full-color devices.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor display devices, and in particular to a method for bonding and transferring a Micro-LED array on a silicon substrate protected by an AlN film. Background Art

[0002] Micro-LEDs, typically composed of LED arrays with individual chips less than 50μm in size, represent a comprehensive hybrid technology that integrates new display technologies with light-emitting diode (LED) technology. Compared to liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays, they offer potential advantages such as low power consumption, high efficiency, high integration, long lifespan, and all-weather operation. They are considered one of the most promising next-generation display and light-emitting devices, with potential applications in flat-panel displays, spatial displays, augmented reality (AR) / virtual reality (VR), and wearable devices.

[0003] Most GaN-based epitaxial wafers used to prepare Micro-LEDs are grown on sapphire or silicon substrates. If the sapphire substrate is not removed, the optical waveguide effect of the sapphire substrate will cause severe optical crosstalk between pixels. If it is a GaN-based epitaxial wafer on a silicon substrate, the silicon substrate must be removed to prepare the micro-display device. There are two ways to remove the silicon substrate. The first is wet etching the silicon substrate. However, since the driver substrate is basically prepared on single crystal silicon, wet etching of the silicon substrate will damage the driver substrate. The second is dry etching to remove the silicon substrate. However, removing the silicon substrate will still damage the driver substrate, as well as the bonding metal layer and metal pads prepared on the surface of the driver substrate. In addition, dry etching will produce difficult-to-clean etching products that adhere to and deposit in the gaps between the Micro-LED arrays, seriously affecting the luminous uniformity of the display device and the subsequent Micro-LED bonding transfer process steps. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for bonding and transferring a Micro-LED array on a silicon substrate using an AlN thin film. This method can protect the bonding metal layer and metal pad on the surface of the driving substrate to the greatest extent, reduce the adhesion and accumulation of etching products, and provide a clean bonding metal surface for subsequent multiple bonding transfers of Micro-LEDs.

[0005] The object of the present invention is achieved like this:

[0006] A first method for bonding and transferring a Micro-LED array on a silicon substrate protected by an AlN film is characterized by comprising the following steps:

[0007] 1) Fabricating a GaN-based micro-LED array consisting of several micro-LEDs on a silicon substrate, wherein the GaN layer between two adjacent micro-LEDs is completely etched through until the silicon substrate is exposed;

[0008] 2) Grow an AlN film on the prepared Micro-LED array, and the AlN film must cover the grooves between the Micro-LED arrays;

[0009] 3) Removing the AlN film on the surface of the Micro-LED's N-type metal electrode layer and P-type metal electrode layer through photolithography and etching processes to expose the surface of the N-type metal electrode layer and P-type metal electrode layer;

[0010] 4) Transfer the Micro-LED array to the driver substrate through bonding;

[0011] 5) The silicon substrate is removed by dry etching using an inductively coupled plasma (ICP) device.

[0012] Preferably, in order to prevent the GaN-based Micro-LED array and the driving substrate from being damaged during the process and to ensure that the AlN film has a very good protective effect, the method for growing the AlN film in step 2) is: using an atomic layer deposition device (ALD) to grow the AlN film at a growth temperature lower than 400°C; because the film prepared by ALD growth has the advantages of high density, good film quality, and good thickness uniformity, it has better resistance to etching during dry etching and can better protect the driving substrate and bonding metal layer during the process of etching and removing the silicon substrate. The growth temperature is lower than 400°C to prevent AlN from forming a crystalline film, which is easy to remove by alkali corrosion.

[0013] Preferably, in step 3), the method for removing the AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: exposing the surface of the N-type metal electrode layer and the P-type metal electrode layer by photolithography and plasma dry etching, the etching gas is Cl2+BCl3, and the etching method is any one of the following: inductively coupled plasma dry etching (Inductively Coupled Plasma dry etching), electron cyclotron resonance plasma etching (Electron Cyclotron Resonance Plasma Etching), reactive ion etching (Reactive Ion Etching), or a combination of the three.

[0014] Preferably, in step 3), the method for removing the AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: first, a layer of SiO2 film is grown on the surface of the AlN film by a plasma enhanced chemical vapor deposition (PECVD) device, and then photolithography and chemical etching are performed to expose the surface of the N-type metal electrode layer and the P-type metal electrode layer.

[0015] Preferably, in step 3), the method for removing the AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: exposing the surface of the N-type metal electrode layer and the P-type metal electrode layer by chemical mechanical polishing.

[0016] Preferably, in step 5), during the dry etching process to remove the silicon substrate, although the AlN film has a good etching selectivity, if the thickness of the silicon substrate is too thick, the etching time of the silicon substrate will be very long, and the AlN film is still not sufficient to achieve complete protection. Therefore, the silicon substrate is thinned to less than 80 μm by mechanical thinning to reduce the time for dry etching to remove the silicon substrate.

[0017] Preferably, the process method for removing the silicon substrate in step 5) is: removing the silicon substrate by dry etching, and the etching gas used is SF6.

[0018] Preferably, after removing the silicon substrate, the AlN film is very thin and easily falls off when attached to the device surface, which is not conducive to the subsequent use of the device. Therefore, the AlN film is removed after removing the silicon substrate. The AlN film is grown using ALD, and the growth temperature is lower than 400°C. This is to prevent the AlN from forming a crystalline film and to facilitate removal by alkaline corrosion. Therefore, the method for removing the AlN film is to use an alkaline solution to etch and remove the AlN film, such as KOH or NaOH, and the alkaline solution corrodes other components of the device very slowly.

[0019] A second method for bonding and transferring a Micro-LED array on a silicon substrate protected by an AlN film is characterized by comprising the following steps:

[0020] 1) Fabricating a GaN-based micro-LED array consisting of several micro-LEDs on a silicon substrate, wherein the GaN layer between two adjacent micro-LEDs is completely etched through until the silicon substrate is exposed;

[0021] 2) Grow a first layer of AlN film on the prepared Micro-LED array, and the first layer of AlN film must cover the grooves between the Micro-LED arrays;

[0022] 3) Removing the first AlN film on the surface of the Micro-LED's N-type metal electrode layer and P-type metal electrode layer through photolithography and etching processes to expose the surface of the N-type metal electrode layer and P-type metal electrode layer;

[0023] 4) Transfer the Micro-LED array to the driver substrate through bonding;

[0024] 5) growing a second layer of AlN film on the surface of the device after bonding and transfer in step 4;

[0025] 6) Thinning the silicon substrate to less than 80 μm by mechanical thinning;

[0026] 7) The silicon substrate is removed by dry etching using an inductively coupled plasma (ICP) device.

[0027] Preferably, in order to prevent the GaN-based Micro-LED array and the driving substrate from being damaged during the process, and the AlN film has a very good protective effect, the method of growing the first layer of AlN film in the step 2) is: using an atomic layer deposition device (ALD) to grow the first layer of AlN film, and the growth temperature is lower than 400 ° C; because the film prepared by ALD growth has the advantages of high density, good film quality, good thickness uniformity, etc., it has better etching resistance during dry etching, and can better protect the driving substrate and bonding metal layer during the process of etching and removing the silicon substrate. The growth temperature is lower than 400 ° C to prevent AlN from forming a crystalline film, which is easy to be removed by alkaline corrosion.

[0028] Preferably, in step 3), the method for removing the first AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: exposing the surface of the N-type metal electrode layer and the P-type metal electrode layer by photolithography and plasma dry etching, the etching gas is Cl2+BCl3, and the etching method is any one of the following: inductively coupled plasma dry etching (Inductively Coupled Plasma dry etching), electron cyclotron resonance plasma etching (ElectronCyclotronResonancePlasmaEtching), reactive ion etching (ReactiveIonEtching), or a combination of the three.

[0029] Preferably, in step 3), the method for removing the first AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: first, a SiO2 film is grown on the surface of the first AlN film by a plasma enhanced chemical vapor deposition (PECVD) device, and then photolithography and chemical etching are performed to expose the surface of the N-type metal electrode layer and the P-type metal electrode layer.

[0030] Preferably, in step 3), the method for removing the first AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: exposing the surface of the N-type metal electrode layer and the P-type metal electrode layer by chemical mechanical polishing.

[0031] Preferably, in order to obtain a better protection effect, in the step 5), a second layer of AlN film is grown on the surface of the device after the bonding transfer in step 4. The second layer of AlN film is used to cover the area of ​​the surface of the driving substrate that is not covered by the silicon substrate, so that the driving substrate can also be protected during the etching process.

[0032] Preferably, in step 7), during the dry etching process to remove the silicon substrate, although the AlN film has a good etching selectivity, if the thickness of the silicon substrate is too thick, the etching time of the silicon substrate will be very long, and the AlN film is still not sufficient to achieve complete protection. Therefore, the silicon substrate is thinned to less than 80 μm by mechanical thinning to reduce the time for dry etching to remove the silicon substrate.

[0033] Preferably, the process method for removing the silicon substrate in step 7) is: removing the silicon substrate by ICP dry etching, and the etching gas used is SF6.

[0034] Preferably, after removing the silicon substrate, the AlN film is very thin and easily falls off when attached to the device surface, which is not conducive to the subsequent use of the device. Therefore, the AlN film is removed after removing the silicon substrate. The AlN film is grown using ALD, and the growth temperature is lower than 400°C. This is to prevent the AlN from forming a crystalline film and to facilitate removal by alkaline corrosion. Therefore, the method for removing the AlN film is to use an alkaline solution to etch and remove the AlN film, such as KOH or NaOH, and the alkaline solution corrodes other components of the device very slowly.

[0035] The present invention has the following characteristics:

[0036] 1. The AlN film as a protective layer has the advantage of a high etching selectivity ratio with SF6 silicon etchant. It is prepared at a relatively mild temperature (below 400°C) and is relatively easy to remove later. Therefore, the AlN film can play a good selective protection role.

[0037] 2. The AlN film, as a protective layer, can completely fill the gaps between the Micro-LED arrays, maximally protecting the bonding metal layer and metal pads on the driver substrate surface. During the dry etching process to remove the silicon substrate, it can effectively avoid and reduce the adhesion and accumulation of etching products, thereby providing a relatively clean bonding metal surface for subsequent multiple bonding transfers of Micro-LEDs.

[0038] 3. Due to the good selective protection effect on the unbonded area of ​​the driver substrate, if there is enough gap on the Micro-LED array, multiple bonding is allowed, thus making it possible to prepare dual-color or even multi-color full-color devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A schematic diagram of the structure of a single GaN-based Micro-LED provided in an embodiment of the present invention;

[0040] Figure 2 Schematic diagram of the silicon substrate GaN-based Micro-LED array structure provided by the present invention;

[0041] Figure 3 A schematic diagram of the Micro-LED array structure with AlN thin film provided by the present invention;

[0042] Figure 4 A schematic structural diagram of the drive substrate provided by the present invention;

[0043] Figure 5 This is a schematic diagram of the structure after the blue light Micro-LED array provided by the present invention is bonded to the driving substrate;

[0044] Figure 6 This is a schematic diagram of the structure of the present invention in which the blue light Micro-LED array is bonded to the substrate and the silicon substrate is removed;

[0045] Figure 7 This is a schematic diagram of the structure of the blue light Micro-LED array after bonding to the substrate and removing the AlN;

[0046] Figure 8 This is a schematic diagram of the structure after the green light Micro-LED array provided by the present invention is bonded to the substrate;

[0047] Figure 9 A schematic diagram of the structure of growing a second AlN protective layer provided by the present invention;

[0048] Figure 10 This is a schematic diagram of the structure of the green light Micro-LED array provided by the present invention, after bonding with the substrate and thinning the silicon substrate;

[0049] Figure 11 This is a schematic diagram of the structure of the present invention in which the green light Micro-LED array is bonded to the substrate and the silicon substrate is removed;

[0050] Figure 12 This is a schematic diagram of the structure of the green light Micro-LED array after bonding to the substrate and removing the AlN;

[0051] Figure 13 This is a schematic diagram of the structure of the Micro-LED (a type of RGB) array of the present invention;

[0052] Figure 14 This is a schematic diagram of the structure of the AlN thin film Micro-LED (a type of RGB) array of the present invention;

[0053] Figure 15 Schematic diagram of the structure of the Micro-LED (R) array and the substrate after the first bonding of the present invention;

[0054] Figure 16 This is a schematic diagram of the structure of removing the silicon substrate after the first bonding of the present invention;

[0055] Figure 17 This is a schematic diagram of the structure of removing the AlN film after the first bonding of the present invention;

[0056] Figure 18 Schematic diagram of the structure of the Micro-LED (G) array and the substrate after the second bonding of the present invention;

[0057] Figure 19 This is a schematic structural diagram of the present invention in which the silicon substrate is removed after the second bonding;

[0058] Figure 20 This is a schematic diagram of the structure of removing the AlN film after the second bonding of the present invention;

[0059] Figure 21 Schematic diagram of the structure of the Micro-LED (B) array and the substrate after the third bonding of the present invention;

[0060] Figure 22 This is a schematic diagram of the structure of removing the silicon substrate after the third bonding of the present invention;

[0061] Figure 23 This is a schematic diagram of the structure of removing the AlN film after the third bonding of the present invention;

[0062] Wherein, the accompanying drawings are marked as follows:

[0063] 1-Silicon substrate, 201-N-type GaN layer, 202-InGaN / GaN multi-quantum well layer, 203-P-type GaN layer, 3-Passivation layer, 4-P-type metal electrode layer, 5-N-type metal electrode layer, 6-First AlN film, 7-Bonding metal layer, 8-Drive substrate, 9-Micro-LED, 10-Micro-LED array, 11-Second AlN film. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0065] Example 1:

[0066] A method for bonding and transferring a blue light Micro-LED comprises the following steps:

[0067] 1) If Figure 1 Figure 2 is a schematic diagram of a GaN-based Micro-LED structure on a silicon substrate, which includes an N-type GaN layer 201, an InGaN / GaN blue light multi-quantum well layer 202, a P-type GaN layer 203, a passivation layer 3 prepared by thin film deposition technology, and an N-type metal electrode layer 5 and a P-type metal electrode layer 4 prepared by metal evaporation technology.

[0068] 2) If Figure 2 As shown, a blue light Micro-LED array 10 is prepared by techniques such as photolithography, etching, thin film deposition and metal evaporation, wherein the size of a single Micro-LED 9 is 10 μm×10 μm;

[0069] 3) If Figure 3 As shown, Figure 2 The blue light micro-LED array 10 shown is formed by growing a 100 nm thick AlN film 6 by ALD at 350°C. The AlN film 6 on the bonding metal electrode surface is then removed by photolithography and etching, exposing the bonding metal electrode surface (corresponding to the surface of the N-type metal electrode layer 5 and the P-type metal electrode layer 4 in the figure). The photoresist and other masks are then removed to obtain the desired blue light micro-LED array 10.

[0070] 4) If Figure 4 As shown, a bonding metal layer 7 is prepared on a driving substrate 8 by photolithography, etching and evaporation processes;

[0071] 5) Before bonding, perform surface cleaning and treatment, such as Ar plasma treatment, to obtain a metal surface that is easier to bond (the surface of the N-type metal electrode layer 5, the P-type metal electrode layer 4, and the bonding layer metal 7);

[0072] 6) If Figure 5 As shown, alignment bonding equipment is used to perform alignment bonding, and the blue light Micro-LED array 10 is bonded and transferred to the Figure 4 On the driving substrate 8 shown;

[0073] 7) Thinning the silicon substrate 1 of the sample to less than 80 μm using a mechanical thinning device so that the etching removal of the silicon substrate 1 can be completed in a relatively short time and the driving substrate 8 can be well protected from damage;

[0074] 8) If Figure 6 As shown, the silicon substrate 1 is removed by ICP dry etching, and the etching gas used is SF6;

[0075] 9) If Figure 7 As shown, the AlN film 6 is corroded by KOH solution to achieve bonding transfer of the blue light Micro-LED array to the driving substrate 8.

[0076] Example 2:

[0077] A green light Micro-LED bonding transfer method includes the following steps:

[0078] 1) If Figure 1 Figure 2 is a schematic diagram of a GaN-based Micro-LED structure on a silicon substrate, showing an N-type GaN layer 201, an InGaN / GaN green light multi-quantum well layer 202, a P-type GaN layer 203, a passivation layer 3 prepared by thin film deposition technology, and an N-type metal electrode layer 5 and a P-type metal electrode layer 4 prepared by metal evaporation technology.

[0079] 2) If Figure 2 As shown, a green light Micro-LED array 10 is prepared by techniques such as photolithography, etching, thin film deposition and metal evaporation. The size of a single Micro-LED 9 is 5μm×10μm;

[0080] 3) If Figure 3 As shown, Figure 2 The green light micro-LED array 10 shown is formed by growing a first 150 nm thick AlN film 6 by ALD at 400°C. The first AlN film 6 is then removed from the bonding metal electrode surface by photolithography and etching, exposing the bonding metal electrode surface (corresponding to the surface of the N-type metal electrode layer 5 and the P-type metal electrode layer 4 in the figure). The photoresist and other masks are then removed to obtain the desired green light micro-LED array 10.

[0081] 4) Before bonding, the surface is cleaned and treated, such as Ar plasma treatment, to obtain a metal surface that is easier to bond (the surface of the N-type metal electrode layer 5, the P-type metal electrode layer 4, and the bonding layer metal 7);

[0082] 5) If Figure 8 As shown, the green light Micro-LED array 10 is bonded and transferred to the bonding pad as shown in FIG. Figure 4 On the driving substrate 8 shown;

[0083] 6) If Figure 9 As shown, a second layer of AlN film 11 is grown on the surface of the sample after bonding transfer by ALD to protect the driving substrate 8 during the process of removing the silicon substrate;

[0084] 7) If Figure 10 As shown, the silicon substrate 1 of the sample is thinned to less than 80 μm by a mechanical thinning device, so that the etching removal of the silicon substrate 1 can be completed in a shorter time and the driving substrate 8 can be well protected from damage;

[0085] 8) If Figure 11 As shown, the silicon substrate 1 is removed by ICP dry etching, and the etching gas used is SF6;

[0086] 9) If Figure 12 As shown, the first AlN film 6 and the second AlN film 11 are etched by KOH solution to achieve bonding transfer of the green light Micro-LED 10 to the driving substrate 8.

[0087] Example 3:

[0088] A red, green, and blue Micro-LED full-color bonding transfer method includes the following steps:

[0089] 1) If Figure 1 Schematic diagram of the GaN-based Micro-LED structure on a silicon substrate, including an N-type GaN layer 201, an InGaN / GaN multi-quantum well layer 202, a P-type GaN layer 203, a passivation layer 3 prepared by thin film deposition technology, and an N-type metal electrode layer 5 and a P-type metal electrode layer 4 prepared by metal evaporation technology;

[0090] 2) If Figure 13 As shown in FIG, a schematic diagram of the structure of a red, green, and blue micro-LED array 10 prepared by photolithography, etching, thin film deposition, and metal evaporation techniques. The size of a single micro-LED 9 is 8 μm × 8 μm.

[0091] 3) If Figure 14 As shown, in Figure 13 A 100 nm thick AlN film 6 is grown on the red light micro-LED array 10 by ALD at 350°C. The AlN film 6 on the surface of the bonding metal electrode is removed by photolithography and etching to expose the bonding metal electrode surface (corresponding to the surface of the N-type metal electrode layer 5 and the P-type metal electrode layer 4 in the figure). The photoresist and other masks are removed to obtain the desired red light micro-LED array 10.

[0092] 4) Before bonding, the surface is cleaned and treated, such as Ar plasma treatment, to obtain a metal surface that is easier to bond (the surface of the N-type metal electrode layer 5, the P-type metal electrode layer 4, and the bonding layer metal 7);

[0093] 5) If Figure 15 As shown, the red light Micro-LED array 10 is bonded and transferred to the driving substrate 8 by alignment and bonding equipment;

[0094] 6) Thinning the silicon substrate 1 of the sample to less than 80 μm by mechanical thinning equipment so that the etching removal of the silicon substrate 1 can be completed in a relatively short time and the driving substrate 8 can be well protected from damage;

[0095] 7) If Figure 16 As shown, the silicon substrate 1 is removed by ICP dry etching, and the etching gas used is SF6;

[0096] 8) If Figure 17 As shown, the AlN film 6 is corroded by KOH solution to complete the bonding transfer process of the red light Micro-LED array 10;

[0097] 9) If Figure 14 As shown, in Figure 13 A 100 nm thick AlN film 6 is grown on the green Micro-LED array 10 by ALD at 350°C. The AlN film 6 on the bonding metal electrode surface is then removed by photolithography and etching, exposing the bonding metal electrode surface (corresponding to the surface of the N-type electrode layer 5 and the P-type electrode layer 4 in the figure). The photoresist and other masks are then removed to obtain the desired green Micro-LED array 10.

[0098] 10) Before bonding, perform surface cleaning and treatment, such as Ar plasma treatment, to obtain a metal surface that is easier to bond (the surface of the N-type metal electrode layer 5, the P-type metal electrode layer 4, and the bonding layer metal 7);

[0099] 11) If Figure 18 As shown, the green light Micro-LED array 10 is transferred to the Figure 17The driving substrate 8 after the first red light Micro-LED bonding transfer is completed is shown;

[0100] 12) Thinning the silicon substrate 1 of the sample to less than 80 μm by mechanical thinning equipment, so that the etching removal of the silicon substrate 1 can be completed in a relatively short time and the driving substrate 8 can be well protected from damage;

[0101] 13) If Figure 19 As shown, the silicon substrate 1 is removed by ICP dry etching, and the etching gas used is SF6;

[0102] 14) If Figure 20 As shown, the AlN film 6 is etched by KOH solution to complete the bonding transfer process of the green light Micro-LED array 10;

[0103] 15) If Figure 20 As shown, it is a schematic diagram of the sample structure after the red and green Micro-LED bonding transfer is completed;

[0104] 16) If Figure 14 As shown, in Figure 13 A 100 nm thick AlN film 6 is grown on the blue light micro-LED array 10 by ALD at 350°C. Then, photolithography is performed to expose the bonding metal electrode surface (corresponding to the surface of the N-type electrode layer 5 and the P-type electrode layer 4 in the figure), and the AlN film 6 on the bonding metal surface is removed. The photoresist and other masks are removed to obtain the desired blue light micro-LED array 10.

[0105] 17) Before bonding, perform surface cleaning and treatment, such as Ar plasma treatment, to obtain a metal surface that is easier to bond (the surface of the N-type metal electrode layer 5, the P-type metal electrode layer 4, and the bonding layer metal 7);

[0106] 18) If Figure 21 As shown, the blue light Micro-LED array 10 is transferred to the Figure 20 The red and green Micro-LEDs are bonded and transferred onto the driver substrate.

[0107] 19) Thinning the sample silicon substrate 1 to less than 80 μm using a mechanical thinning device so that the silicon substrate 1 can be etched and removed in a relatively short time while protecting the drive substrate 8 from damage;

[0108] 20) Such as Figure 22 As shown, the silicon substrate 1 is removed by ICP dry etching, and the etching gas used is SF6;

[0109] 21) If Figure 23As shown, the grown AlN film 6 is removed by KOH solution to complete the blue light Micro-LED bonding transfer process;

[0110] 22) If Figure 23 As shown, it is a schematic diagram of the structure of a full-color display device that completes the bonding transfer of red, green and blue Micro-LEDs and the driving substrate 8.

[0111] It should be noted that the steps described in the above embodiments do not necessarily need to be completed in the exact order listed; their order can be adjusted appropriately based on the equipment used and other conditions. The present invention does not impose any particular restrictions on the etching conditions for the AlN film, and the bonding temperature and pressure can also be appropriately adjusted based on the specific equipment conditions or the experience of those skilled in the art. Such adjustments also fall within the scope of protection of the technical solutions of the present invention.

[0112] In the above-described embodiments, the AlN is limited to an overview of a substance in this professional field. Adding a small amount of Ga, In or other metal elements to the AlN material also falls within the scope of protection of the technical solution of the present invention as long as it does not significantly change the chemical and physical properties of AlN.

[0113] The embodiments described above are only a few typical examples of our implementation of this solution. The thickness adjustment, growth temperature fine-tuning, spacing adjustment, and color combination based on these embodiments do not change the essence of my patent. These solutions are all within the scope of the rights described in this patent.

Claims

1. A method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate, characterized by: The following steps are involved: 1) Fabricating a GaN-based micro-LED array consisting of several micro-LEDs on a silicon substrate, wherein the GaN layer between two adjacent micro-LEDs is completely etched through until the silicon substrate is exposed; 2) Grow an AlN film on the prepared Micro-LED array, and the AlN film must cover the grooves between the Micro-LED arrays; 3) Removing the AlN film on the surface of the Micro-LED's N-type metal electrode layer and P-type metal electrode layer through photolithography and etching processes to expose the surface of the N-type metal electrode layer and P-type metal electrode layer; 4) Transfer the Micro-LED array to the driver substrate through bonding; 4.1) A second AlN film is grown on the surface of the device after bonding and transfer in step 4); 4.2) Thinning the silicon substrate to less than 80 μm by mechanical thinning; 5) The silicon substrate is removed by dry etching using an inductively coupled plasma device.

2. The method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate according to claim 1, characterized in that: The method for growing the AlN film in step 2) is: growing the AlN film using an atomic layer deposition device at a growth temperature lower than 400°C.

3. The method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate according to claim 1, characterized in that: In step 3), the method for removing the AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: exposing the surface of the N-type metal electrode layer and the P-type metal electrode layer by photolithography and plasma dry etching, the etching gas is Cl2+BCl3, and the etching method is any one of the following: inductively coupled plasma dry etching, electron cyclotron resonance plasma etching, reactive ion etching, or a combination of the three.

4. The method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate according to claim 1, wherein: In step 3), the method for removing the AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: first, a layer of SiO2 film is grown on the surface of the AlN film using a plasma enhanced chemical vapor deposition device, and then photolithography and chemical etching are performed to expose the surface of the N-type metal electrode layer and the P-type metal electrode layer.

5. The method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate according to claim 1, wherein: In step 3), the method for removing the AlN film on the surface of the N-type metal electrode layer and the P-type metal electrode layer is: exposing the surface of the N-type metal electrode layer and the P-type metal electrode layer by chemical mechanical polishing.

6. The method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate according to claim 1, wherein: In the step 5), the process method for removing the silicon substrate is: removing the silicon substrate by dry etching, and the etching gas used is SF6.

7. The method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate according to claim 1, wherein: After step 5), the AlN film is removed by etching with a KOH or NaOH alkaline solution.

8. The method for bonding and transferring a Micro-LED array on an AlN film-protected silicon substrate according to claim 1, wherein: In step 4.1), a second layer of AlN film grows on the surface of the device after bonding transfer in step 4). The second layer of AlN film is used to cover the area of ​​the driving substrate surface not covered by the silicon substrate, so that the driving substrate can also be protected during the etching process.

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