Manufacturing method of light-emitting module and light-emitting module

Abstract

The invention relates to a manufacturing method of a light-emitting module and the light-emitting module. The manufacturing method of the light-emitting module comprises the steps that a driving substrate is provided; a conductive layer and a plurality of epitaxial structures electrically connected with the conductive layer are arranged on the driving substrate; arranging a mask layer on the epitaxial structure, wherein the mask layer at least covers and protects the epitaxial structure and exposes the to-be-etched region of the conductive layer; wherein the mask layer comprises a first photoresist layer covering the epitaxial structure and a second photoresist layer arranged on the first photoresist layer, and the second photoresist layer has a developing condition different from that of the first photoresist layer; etching a to-be-etched region of the conductive layer under the protection of the mask layer so as to form a plurality of first electrodes on the conductive layer; wherein an attachment is formed on the mask layer when the conductive layer is etched; and removing the mask layer. The mask layer can be removed through a simple technological process, the structure formed at the epitaxial structure is simplified, and a high-quality light-emitting module can be formed.

Description

Technical Field

[0001] This application relates to the field of LED (Light Emitting Diode) modules, and particularly to a manufacturing method of a light emitting module and a light emitting module. Background Art

[0002] With the gradual marketization of Micro LED (Micro Light Emitting Diode) technology at the present stage, various technical routes have emerged. In some related technologies, technical routes such as Wafer Bonding are gradually adopted by various manufacturers to manufacture light emitting modules.

[0003] However, in some technical routes for manufacturing light emitting modules, the mask layer set during the etching process is difficult to remove, and the obtained chip source structure often retains redundant structures such as the mask layer, which is not conducive to forming a higher-quality light emitting module.

[0004] Therefore, how to more easily manufacture a light emitting module with a relatively simplified structure is an urgent problem to be solved. Summary of the Invention

[0005] In view of the above deficiencies in the related technologies, the purpose of this application is to provide a manufacturing method of a light emitting module and a light emitting module, aiming to solve the problem that the mask layer set during some etching processes is difficult to remove, and the obtained chip source structure often retains redundant structures such as the mask layer, which is not conducive to forming a higher-quality light emitting module.

[0006] A manufacturing method of a light emitting module includes:

[0007] Providing a driving substrate;

[0008] Setting a conductive layer and a plurality of epitaxial structures electrically connected to the conductive layer on the driving substrate;

[0009] Setting a mask layer on the epitaxial structure, the mask layer at least covering and protecting the epitaxial structure and exposing the area to be etched of the conductive layer; wherein, the mask layer includes a first photoresist layer covering the epitaxial structure and a second photoresist layer provided on the first photoresist layer, and the second photoresist layer has different developing conditions from the first photoresist layer;

[0010] Etching the area to be etched of the conductive layer under the protection of the mask layer to form the conductive layer into a plurality of first electrodes; wherein, when etching the conductive layer, an attachment is formed on the mask layer;

[0011] Removing the mask layer.

[0012] In the method for manufacturing the above-mentioned light-emitting module, a photoresist is used as an etching mask layer. After the etching of the conductive layer is completed, the mask layer can be removed by means of photoresist removal, and at the same time, the attachments adhered to the mask layer during the etching process are removed together. The process of photoresist removal is relatively simple, and there are mature processes and equipment, which can remove the mask layer through a simple process, simplify the structure formed at the epitaxial structure, and facilitate the formation of a high-quality light-emitting module.

[0013] Optionally, the thickness of the first photoresist layer is less than the thickness of the second photoresist layer.

[0014] Setting the thickness of the first photoresist layer to be smaller enables the aspect ratio of the first development to be relatively small, so that the area to be etched of the conductive layer can be exposed more quickly, ensuring that the sidewalls of the first photoresist layer are not completely removed by the development to have a basic protection effect and reducing the manufacturing difficulty; the second photoresist layer is thicker, which can increase the overall thickness of the mask layer and provide a more effective mask protection ability.

[0015] Optionally, the step of setting a mask layer on the epitaxial structure includes:

[0016] Set a negative first photoresist material;

[0017] Expose and develop the first photoresist material to form the first photoresist layer;

[0018] Set a positive second photoresist material;

[0019] Expose and develop the second photoresist material to form the second photoresist layer, and the development conditions for the second photoresist material during development are different from the development conditions for the first photoresist material during development.

[0020] During the exposure process of the second photoresist material of the second photoresist layer, the exposure boundary is near the edge of the first photoresist layer, so that the edge region of the first photoresist layer can be supplemented with exposure, strengthening the resistance of the first photoresist layer to development and further ensuring the performance of protecting the epitaxial structure.

[0021] Based on the same inventive concept, the present application also provides a light-emitting module, which includes a driving substrate and a light-emitting chip disposed on the driving substrate, and the light-emitting module is manufactured by the above-mentioned method for manufacturing a light-emitting module.

[0022] In the above-mentioned light-emitting module, the mask layer is no longer retained, and the attachments adhered during the etching process are also removed along with the mask layer, so it has a simpler structure and also has good quality in some implementation processes. Description of the Drawings

[0023] Figure 1 Schematic diagram during the manufacturing process of a light-emitting module in the related art;

[0024] Figure 2 Schematic diagram of the etching result during the manufacturing process of a light-emitting module in the related art;

[0025] Figure 3 Basic process schematic diagram of the manufacturing method of the light-emitting module provided by the embodiment of the present application;

[0026] Figure 4 Schematic diagram of the structure during the manufacturing process of the light-emitting module provided by the embodiment of the present application;

[0027] Figure 5 Schematic diagram of long-time development provided by the embodiment of the present application;

[0028] Figure 6 Schematic diagram of the exposure of the second photoresist material provided by the embodiment of the present application;

[0029] Figure 7 Schematic diagram of the structure of a mask layer provided by the embodiment of the present application;

[0030] Figure 8 Schematic diagram of the structure of another mask layer provided by the embodiment of the present application;

[0031] Figure 9 Schematic diagram of the structure of yet another mask layer provided by the embodiment of the present application;

[0032] Figure 10 Schematic diagram of the structure of a first electrode provided by the embodiment of the present application;

[0033] Figure 11 Refined process schematic diagram of the manufacturing method of the light-emitting module provided by the embodiment of the present application Figure 1 ;

[0034] Figure 12 Refined process schematic diagram of the manufacturing method of the light-emitting module provided by the embodiment of the present application Figure 2 ;

[0035] Figure 13 Schematic diagram of the structure of an epitaxial wafer provided by the embodiment of the present application;

[0036] Figure 14 Schematic diagram of the structure of a driving substrate provided by the embodiment of the present application;

[0037] Figure 15 For Figure 13 the structure and Figure 14 the structure key combination to remove the substrate structure schematic diagram;

[0038] Figure 16 Schematic diagram of the detailed process for the manufacturing method of the light-emitting module provided in the embodiment of the present application Figure 3 ;

[0040] Figure 17 Schematic structural diagram of another epitaxial wafer provided in the embodiment of the present application;

[0041] Figure 18 Based on Figure 17 Schematic structural diagram obtained by fabricating the epitaxial wafer;

[0042] Figure 19 Schematic diagram of the detailed process for the manufacturing method of the light-emitting module provided in the embodiment of the present application Figure 4 ;

[0043] Figure 20 Schematic diagram of the manufacturing process of the light-emitting module provided in the embodiment of the present application Figure 1 ;

[0044] Figure 21 Schematic diagram of the manufacturing process of the light-emitting module provided in the embodiment of the present application Figure 2 ;

[0045] Figure 22 Schematic diagram of the manufacturing process of the light-emitting module provided in the embodiment of the present application Figure 3 ;

[0046] Description of reference numerals:

[0047] 1 - driving substrate; 2 - conductive layer; 3 - epitaxial structure; 4 - mask layer; 5 - attachment; 6 - substrate; 7 - epitaxial layer; 8 - current spreading layer; 9 - first bonding layer; 10 - second bonding layer; 11 - contact; 12 - planar sacrificial layer; 13 - insulating planar layer; 14 - second electrode; 21 - first electrode; 41 - first photoresist layer; 42 - second photoresist layer; 400 - photoresist material; 401 - first photoresist material; 402 - second photoresist material; 121 - hole. Detailed Description of the Invention

[0048] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0050] In some applications, a light-emitting module is fabricated by means of Wafer Bonding. As Figure 1 shown, the epitaxial structure 3 is protected by a mask layer 4 made of, for example, SiO2 (silicon dioxide). As Figure 2 shown, the conductive layer 2 is etched into independent electrode patterns. During this process, the attachment 5 formed by the re-deposition of the etched conductive layer 2 will adhere to the mask layer 4, such as the sidewall of the mask layer 4. However, the mask layer 4 is often difficult to remove, and the mask layer 4 and the attachment 5 adhered thereto result in a complex surface morphology of the epitaxial structure 3, which is not conducive to the formation of a high-quality light-emitting module.

[0051] Based on this, the present application hopes to provide a solution capable of solving the above technical problems, and its detailed content will be elaborated in the subsequent embodiments.

[0052] Embodiment:

[0053] The present embodiment provides a method for fabricating a light-emitting module. As Figure 3 shown, the steps include but are not limited to:

[0054] S101. Provide a driving substrate;

[0055] S102. Dispose a conductive layer and a plurality of epitaxial structures electrically connected to the conductive layer on the driving substrate;

[0056] S103. Dispose a mask layer on the epitaxial structure, the mask layer at least covering and protecting the epitaxial structure and exposing the area to be etched of the conductive layer; wherein, the mask layer includes a first photoresist layer covering the epitaxial structure and a second photoresist layer disposed on the first photoresist layer, and the second photoresist layer has different developing conditions from the first photoresist layer;

[0057] S104. Etch the area to be etched of the conductive layer under the protection of the mask layer to form the conductive layer into a plurality of first electrodes;

[0058] S105. Remove the mask layer;

[0059] Referring to Figure 4 , a structure obtained by the above step S103 is exemplified, which includes but is not limited to a driving substrate 1, a conductive layer 2 disposed on the driving substrate 1, a plurality of epitaxial structures 3 disposed on the conductive layer 2, and a mask layer 4 disposed on the epitaxial structure 3.

[0060] In this embodiment, the driving substrate 1 is a circuit board capable of driving and controlling light-emitting chips. For example, it can be a CMOS (Complementary Metal-Oxide-Semiconductor) backplane, a TFT (Thin Film Transistor) backplane, or an LTPS (Low Temperature Poly-Silicon) backplane, etc. The driving substrate 1 can perform control forms on the light-emitting chips, including but not limited to backlight control, display control, etc. The circuits thereon will be configured to achieve the states of corresponding control functions. This embodiment does not limit the specific control forms and circuit patterns thereof.

[0061] It should be noted that the epitaxial structure 3 referred to in this embodiment is the structure formed by the epitaxial material according to the requirements of the light-emitting chip. Each epitaxial structure 3 corresponds to a light-emitting chip. When other structures such as electrodes and passivation layers are provided on the epitaxial structure 3, the epitaxial structure 3 and these structures together form a light-emitting chip. Exemplarily, the epitaxial structure 3 includes but not limited to a first semiconductor layer, an active layer, and a second semiconductor layer, wherein the active layer is disposed between the first semiconductor layer and the second semiconductor layer. One of the first semiconductor layer and the second semiconductor layer is an N-type semiconductor layer, and the other is a P-type semiconductor layer. Among them, the side of the epitaxial structure 3 close to the driving substrate 1 can be an N-type semiconductor layer. In other examples, the side of the epitaxial structure 3 close to the driving substrate 1 can also be a P-type semiconductor layer. Exemplarily, the size of the epitaxial structure 3 can correspond to a Micro LED chip, that is, the light-emitting chip that can be formed based on the epitaxial structure 3 is a Micro LED chip; the size of the epitaxial structure 3 can also correspond to a larger-scale light-emitting chip such as a Mini LED (Mini Light Emitting Diode) chip. This embodiment does not limit this.

[0062] The conductive layer 2 in this embodiment can be made of a conductive metal material or other conductive materials. In practical applications, the conductive layer 2 can be disposed on the driving substrate 1 in a whole-surface manner, and it can be covered on one side of the driving substrate 1 in a whole-surface manner through processes including but not limited to metal deposition. When the conductive layer 2 is disposed in a whole-surface manner, each epitaxial structure 3 is connected to the conductive layer 2. Of course, in the process of manufacturing the light-emitting module, the conductive layer 2 can be divided into a form corresponding one-to-one to the epitaxial structures 3 to form electrodes for the respective epitaxial structures 3. For the convenience of description, the electrode formed after the conductive layer 2 is etched is referred to as the first electrode 21 in this embodiment. In some examples, the conductive layer 2 may not be disposed on the driving substrate 1 in a whole-surface manner, that is, it can be configured in other forms, such as directly corresponding one-to-one to the epitaxial structures 3. However, it should be understood that before etching through step S104, the conductive layer 2 has not yet been formed into the pattern of the first electrode 21. In the subsequent step S104, the mask layer 4 is used to protect the area to be etched of the conductive layer 2 and etch it so that the conductive layer 2 is formed into the first electrode 21 of the epitaxial structure 3. In this embodiment, the conductive layer 2 can be a single-layer structure or a composite structure of at least two layers or multiple layers. As an example, the conductive layer 2 can include a bonding metal layer and a current spreading layer 8. The bonding metal layer can be an alloy formed by one or more of metal materials such as titanium, aluminum, gold, chromium, platinum, indium, tin, and silver. The current spreading layer 8 can be a transparent conductive material such as indium tin oxide (ITO for short) that can form an ohmic contact with the corresponding semiconductor material, and also for example: graphene, indium zinc oxide (IZO for short), other thin metal film layers, etc. Among them, the current spreading layer 8 is close to the epitaxial structure 3 and is used to form an ohmic contact therewith, and the bonding metal layer is responsible for forming a connection with the driving substrate 1.

[0063] It can be understood that the mask layer 4 at least covers and protects the epitaxial structure 3 and exposes the area to be etched of the conductive layer 2. In the traditional process of manufacturing a light-emitting module, the mask layer 4 is a hard mask made of materials such as SiO2, which is difficult to remove and the process is complex, and it is usually directly retained. In this embodiment, the mask layer 4 includes a first photoresist layer 41 covering the epitaxial structure 3 and a second photoresist layer 42 disposed on the first photoresist layer 41. The second photoresist layer 42 has different developing conditions from the first photoresist layer 41. Different developing conditions mean that the pattern of the first photoresist layer 41 will not be affected during the development process of the second photoresist layer 42.

[0064] During the etching process, the areas not protected by the mask layer 4 will be removed. When etching the conductive layer 2, an attachment 5 is formed on the mask layer 4. In traditional processes, the mask layer 4 is usually configured as a single-layer structure, that is, one layer of mask material corresponds to one etching. In practical applications, multiple epitaxial structures 3 can be arranged relatively densely. With the improvement of display requirements, in products such as Micro LED technology, the gap between adjacent epitaxial structures 3 is continuously shrinking, resulting in a large aspect ratio between adjacent epitaxial structures 3. The photosensitive degree of the exposed area of the photoresist is also different at different depths, and there are also differences in the development speed at different depths. As shown in Figure 5 As shown, the photoresist is isotropic during development, that is, the downward development rate and the lateral development rate are the same. Coupled with the difference in photosensitive degree at different depths, the developed photoresist layer will form an inclined sidewall shape. When the space between adjacent epitaxial structures 3 has a high aspect ratio, a longer development time is required to ensure that the area to be etched of the conductive layer 2 is exposed. The long development time may cause the lateral photoresist to be completely removed before the area to be etched of the conductive layer 2 is exposed, and it cannot effectively protect the epitaxial structure 3. This also promotes the use of hard masks made of materials such as SiO2 in traditional processes. The mask layer 4 in this embodiment uses two photoresists with different development conditions. When the second photoresist layer 42 is developed, it does not affect the pattern of the first photoresist layer 41 or has a slow influence, and it can make the second photoresist layer 42 not easily directly expose the epitaxial structure 3 even after a long development time. Therefore, such a structural design of the mask layer 4 can more effectively form a mask protection for the epitaxial structure 3 array with a high aspect ratio.

[0065] In this embodiment, a photoresist is used as the mask layer 4 for etching. When manufacturing a light-emitting module using the manufacturing method of the light-emitting module in this embodiment, after the etching of the conductive layer 2 is completed, the mask layer 4 can be removed by means of photoresist removal, and at the same time, the attachment 5 adhered to the mask layer 4 during the etching process is removed together. The process of photoresist removal is relatively simple, and there are mature processes and equipment. The mask layer 4 can be removed through a simple process, simplifying the structure formed at the epitaxial structure 3, which is beneficial to forming a high-quality light-emitting module.

[0066] In some embodiments, the photosensitive properties of the first photoresist layer 41 and the second photoresist layer 42 are opposite, that is, one of them is a positive photoresist and the other is a negative photoresist. Among them, the exposed part of the positive photoresist is removed after development, and the exposed part of the negative photoresist is retained after development. By using the first photoresist layer 41 and the second photoresist layer 42 with opposite photosensitive properties, it is easier to distinguish and control during the exposure and development process, the difference in development conditions is obvious, and the accuracy and protection performance of the mask layer 4 are better.

[0067] In an example of this embodiment, the first photoresist layer 41 is a negative photoresist, and the second photoresist layer 42 is a positive photoresist. Positive photoresists generally have better resolution and plasticity compared to negative photoresists. In this embodiment, the development duration of the second photoresist layer 42 is usually longer, and the positive second photoresist layer 42 can achieve a more accurate development effect. As Figure 6 shown, the area corresponding to the arrow in the figure is the area where the second photoresist material 402 is exposed. The exposed part of the negative first photoresist material 401 will be retained during development to form the first photoresist layer 41. During the exposure of the second photoresist material 402 of the second photoresist layer 42, its exposure boundary is near the edge of the first photoresist layer 41, so that the edge area of the first photoresist layer 41 can be additionally exposed, strengthening the resistance of the first photoresist layer 41 to development and further ensuring the performance of protecting the epitaxial structure 3.

[0068] In some embodiments, the thickness of the first photoresist layer 41 is less than that of the second photoresist layer 42. It can be understood that when setting the mask layer 4, the first photoresist layer 41 will be exposed and developed prior to the second photoresist layer 42. By setting the thickness of the first photoresist layer 41 to be smaller, the aspect ratio of the first development can be relatively small, and the area of the conductive layer 2 to be etched can be exposed more quickly, ensuring that the sidewall of the first photoresist layer 41 is not completely removed by development to have a basic protection effect and reducing the manufacturing difficulty. Since the development conditions of the second photoresist layer 42 are different from those of the first photoresist layer 41, even with a long development time, it is not easy to directly expose the epitaxial structure 3. Then, the thickness of the second photoresist layer 42 can be made thicker, which can increase the overall thickness of the mask layer 4 and provide a more effective mask protection ability.

[0069] Traditional dry etching is difficult to directly and accurately trim the edge of the conductive layer 2. Refer to Figure 7 and Figure 8 shown. In some embodiments, the edge of the mask layer 4 is configured to be ramp-shaped or stepped. It can be understood that compared with a hard mask made of materials such as SiO2, the edge shape of the photoresist can be adjusted by process control during exposure and development, and can be designed more flexibly. It should be noted that the edge of the mask layer 4 can be jointly formed by the first photoresist layer 41 and the second photoresist layer 42. In other examples, such as Figure 9 , the second photoresist layer 42 can also completely cover the first photoresist layer 41, and then the edge of the mask layer 4 is only determined by the shape of the second photoresist layer 42. Refer to Figure 10As shown, in some implementation processes, the etching performed based on this structure will transfer the shape of the mask layer 4 onto the conductive layer 2, such that the edge of the formed first electrode 21 is formed into a ramp shape or a stepped shape. Compared with a vertical sidewall or a sidewall that is recessed at the bottom, a ramp shape or a stepped shape is more likely to adhere to materials and has a relatively larger surface area, and the subsequent formed film layers such as a passivation layer have better coating properties.

[0070] In this embodiment, the first electrodes 21 may correspond one-to-one with the epitaxial structures 3, that is, each epitaxial structure 3 will be configured with an independent first electrode 21, and the first electrodes 21 of the respective epitaxial structures 3 are not connected to each other. In fact, this process achieves the effect of dividing the conductive layer 2 into multiple independent regions.

[0071] The etching may be dry etching, for example, including but not limited to ICP (Inductively Coupled Plasma) etching or IBE (Ion Beam Etching) etching, etc. During the dry etching process, the material of the conductive layer 2 will redeposit onto the mask layer 4 to form an attachment 5, especially on the sidewalls of the mask layer 4. The mask layer 4 also isolates these conductive attachments 5 from touching the epitaxial structure 3. It can be understood that the mask layer 4 should ensure the stability of the overall shape during the dry etching process. Taking the ICP etching process as an example, in some implementation processes, the ICP etching is carried out under the condition of an ambient temperature of about 150°C, then the mask layer 4 may adopt a photoresist such as the model NR7-6000P whose heat resistance can meet the requirements and will not produce gum paste and cause deformation at about 150°C. In practical applications, the specific materials of the first photoresist layer 41 and the second photoresist layer 42 may be selected according to the requirements of subsequent etching or other processes, and this embodiment does not limit them.

[0072] The mask layer 4 can be removed by corresponding photoresist removal means. Compared with a hard mask made of materials such as SiO2, the removal method of the mask layer 4 in this embodiment is simple and is not likely to affect the already fabricated structure. When the mask layer 4 is removed, the attachments 5 redeposited thereon are also removed. In some implementation processes, after the mask layer 4 is removed, the residue of the material of the conductive layer 2 can be further cleaned, which is beneficial to forming a better quality of the light-emitting module. In some implementation manners, referring to Figure 11 , the steps of disposing the mask layer 4 on the epitaxial structure 3 include but are not limited to:

[0073] S201. Dispose a first photoresist material, and the first photoresist material is negative;

[0074] S202. Expose and develop the first photoresist material to form a first photoresist layer;

[0075] S203. Set the second photoresist material, and the first photoresist material is positive;

[0076] S204. Expose and develop the second photoresist material to form a second photoresist layer. The developing conditions for the second photoresist material during development are different from those for the first photoresist material during development.

[0077] In this embodiment, the epitaxial structure 3 and the driving substrate 1 can be bonded through the wafer bonding process. As Figure 12 shown, the steps of setting the conductive layer 2 and a plurality of epitaxial structures 3 electrically connected to the conductive layer 2 on the driving substrate 1 include but are not limited to:

[0078] S301. Provide an epitaxial wafer, which includes a substrate and an epitaxial layer formed on the substrate;

[0079] The substrate 6 can be a growth substrate such as a sapphire substrate that can grow an epitaxial layer 7.

[0080] S302. Set a first bonding layer on the epitaxial layer;

[0081] The first bonding layer 9 can be an alloy formed by one or more of metal materials such as titanium, aluminum, gold, chromium, platinum, indium, tin, silver, etc., or a non-metal conductive material capable of achieving bonding. As Figure 13 shown, in some embodiments, before setting the first bonding layer 9 on the epitaxial wafer, a current spreading layer 8 is also set on the epitaxial wafer to form a better ohmic contact with the epitaxial structure 3.

[0082] S303. Set a second bonding layer on the driving substrate;

[0083] The second bonding layer 10 can be an alloy formed by one or more of metal materials such as titanium, aluminum, gold, chromium, platinum, indium, tin, silver, etc., or a non-metal conductive material capable of achieving bonding; the second bonding layer 10 can be the same as or different from the material of the first bonding layer 9. In some embodiments, a current spreading layer 8 can also be formed between the second bonding layer 10 and the driving substrate 1.

[0084] As Figure 14 shown, the driving substrate 1 has driving circuits. In this embodiment, the conductive layer 2 can be connected to the driving circuits through the contacts 11. In practical applications, the driving substrate 1 can also be any other structure, and this embodiment does not limit this.

[0085] S304. Bond the epitaxial wafer to the driving substrate so that the first bonding layer and the second bonding layer are bonded to form a conductive layer;

[0086] The epitaxial wafer and the driving substrate 1 are integrated by bonding metal. The first bonding layer 9 and the second bonding layer 10 are bonded to form the conductive layer 2. During the bonding process, means such as pressurization and / or heating can be used to achieve a more efficient and better bonding effect.

[0087] S305. Remove the substrate of the epitaxial wafer;

[0088] Taking the substrate 6 made of sapphire as an example, the substrate 6 can be removed by means such as laser lift-off. The structure after removing the substrate 6 is as Figure 15 shown.

[0089] S306. Form the epitaxial layer into a plurality of epitaxial structures;

[0090] Etch the epitaxial layer 7 bonded to the driving substrate 1, and the epitaxial layer 7 can be fabricated into the required epitaxial structure 3.

[0091] See Figure 16 shown. As another example, in this embodiment, the steps of setting the conductive layer 2 and a plurality of epitaxial structures 3 electrically connected to the conductive layer 2 on the driving substrate 1 may further include, but are not limited to:

[0092] S401. Provide an epitaxial wafer, which includes a substrate, a plurality of epitaxial structures provided on the substrate, and a planar sacrificial layer filled between the epitaxial structures;

[0093] The substrate 6 may be a growth substrate such as a sapphire substrate that can grow epitaxial materials, or the epitaxial materials can also be grown on the growth substrate and then transferred to the substrate 6. The planar sacrificial layer 12 is made of a material that can be removed. Exemplarily, it can be oxide materials such as silicon dioxide and silicon nitride, or heat-resistant polymers or compounds such as aluminum arsenide, etc., and is not specifically limited.

[0094] S402. Set a first bonding layer electrically connected to each epitaxial structure on the epitaxial wafer;

[0095] The first bonding layer 9 may be an alloy formed by one or more of metal materials such as titanium, aluminum, gold, chromium, platinum, indium, tin, silver, etc., or a non-metal conductive material capable of achieving bonding. In some embodiments, before setting the first bonding layer 9 on the epitaxial wafer, a current spreading layer 8 is also set on the epitaxial wafer to form a better ohmic contact with the epitaxial structure 3. As Figure 17 shown, the planar sacrificial layer 12 fills the area between the epitaxial structures 3, so that the epitaxial wafer has a relatively flat surface. When the bonding material is deposited on the epitaxial wafer, a relatively flat first bonding layer 9 is formed.

[0096] S403. Set a second bonding layer on the driving substrate;

[0097] The second bonding layer 10 can be an alloy formed by one or more of metal materials such as titanium, aluminum, gold, chromium, platinum, indium, tin, silver, etc., or a non-metal conductive material capable of achieving bonding; the second bonding layer 10 can be the same as or different from the material of the first bonding layer 9. In some embodiments, a current spreading layer 8 can also be formed between the second bonding layer 10 and the driving substrate 1.

[0098] S404. Bond the epitaxial wafer to the driving substrate so that the first bonding layer and the second bonding layer are bonded to form a conductive layer.

[0099] The epitaxial wafer and the driving substrate 1 are integrated through a bonding metal, and the first bonding layer 9 and the second bonding layer 10 are bonded to form a conductive layer 2. During the bonding process, means such as pressurization and / or heating can be used to achieve a more efficient and better bonding effect.

[0100] S405. Remove the substrate of the epitaxial wafer.

[0101] Taking the substrate 6 made of sapphire as an example, the substrate 6 can be removed by means such as laser lift-off.

[0102] S406. Remove the planar sacrificial layer.

[0103] The removal method of the planar sacrificial layer 12 can be selected according to the material used for the planar sacrificial layer 12. Exemplarily, a wet method can be selected for removal. The structure after removing the planar sacrificial layer 12 is as Figure 18 shown.

[0104] For the structure fabricated by the steps of the manufacturing method of the above light-emitting module in this embodiment, the first photoresist layer 41 and the second photoresist layer 42 of the mask layer 4 have different developing conditions. When the second photoresist layer 42 is developed, it does not affect the pattern of the first photoresist layer 41 or the influence is slow, solving the problem that long-time development is likely to cause the epitaxial structure 3 to lose effective protection. Thus, during the process of fabricating a light-emitting module by technologies such as Wafer Bonding, a mask protection can be effectively formed using the photoresist material. The effective application of the mask layer 4 made of the photoresist material enables the mask layer 4 to be easily removed during the manufacturing process of this embodiment, and the attachment 5 formed during etching is removed together, which is beneficial to simplifying the structure of the light-emitting module.

[0105] In some embodiments, after removing the mask layer, the manufacturing method of the light-emitting module in this embodiment further includes the step of forming a second electrode on the side of the epitaxial structure away from the first electrode.

[0106] Since the mask layer 4 is removed and the epitaxial structure 3 is exposed, the material of the second electrode 14 can be directly provided on the side of the epitaxial structure 3 away from the first electrode 21 and patterned to form the second electrode 14. Exemplarily, the material of the second electrode 14 can be a conductive metal or other conductive material; the material of the second electrode 14 can be the same as or different from that of the first electrode 21.

[0107] In this embodiment, the first electrode 21 and the second electrode 14 are on opposite sides of the epitaxial structure 3, that is, a light-emitting chip with a vertical structure is directly fabricated on the driving substrate 1. Exemplarily, the second electrode 14 can correspond to the epitaxial structure 3 one by one. In some examples, the second electrode 14 can also be a common electrode and be connected to multiple or all of the epitaxial structures 3.

[0108] In some embodiments, referring to Figure 19 , the steps of forming the second electrode 14 on the side of the epitaxial structure 3 away from the first electrode 21 include but are not limited to:

[0109] S501. Set an insulating planarization layer on the driving substrate to fill the gaps between the epitaxial structures.

[0110] The insulating planarization layer 13 is used to provide insulation protection for the epitaxial structure 3. Its material can include but is not limited to aluminum oxide, silicon dioxide, etc. The insulating planarization layer 13 at least covers the sidewalls of the epitaxial structures 3 and exposes the side of the epitaxial structure 3 away from the driving substrate 1, and forms a relatively flat surface around the epitaxial structure 3.

[0111] S502. Deposit the material of the second electrode on the insulating planarization layer and the epitaxial structure to form the second electrode. One second electrode corresponds to multiple epitaxial structures, and the second electrode is connected to the driving substrate.

[0112] It should be noted that the second electrode 14 can be arranged along the side of the insulating planarization layer 13 to be connected to the driving substrate 1; or conductive holes leading to the driving substrate 1 can be formed in the insulating planarization layer 13, and the second electrode 14 is connected to the driving substrate 1 through one or more conductive holes. This embodiment does not limit this.

[0113] This embodiment also provides a light-emitting module, including a driving substrate 1 and a light-emitting chip provided on the driving substrate 1, which is obtained by the foregoing manufacturing method of the light-emitting module. It can be understood that in the light-emitting module of this embodiment, the mask layer 4 is no longer retained, and the attached matter 5 during the etching process is also removed along with the mask layer 4. Therefore, the light-emitting module of this embodiment has a simpler structure and also has better quality in some implementation processes. The light-emitting module of this embodiment can be a backlight module or a display module for display. This embodiment does not limit its application form.

[0114] For better understanding, a complete process of manufacturing a light-emitting module will be described below with reference to a specific example. Refer to Figure 20 , the process of manufacturing a light-emitting module includes but is not limited to:

[0115] S601. Refer to Figure 20 of (a). Provide a substrate 6 and prepare a flat sacrificial layer 12 on the substrate 6. In this example, the epitaxial structure 3 to be fabricated is mainly made of gallium nitride material, and the substrate 6 can be a sapphire substrate. In other examples, the substrate 6 can be other materials capable of growing semiconductor materials, which can be selected according to the epitaxial material to be grown. The flat sacrificial layer 12 is formed with holes 121, and the depth of the holes 121 is the same as the height to which the epitaxial material is to grow, for forming the epitaxial structure 3. The epitaxial structure 3 grown in this example at least includes a first-type semiconductor layer, an active layer, and a second-type semiconductor layer. For the convenience of description, in this embodiment, only the N-type doping is taken as an example on the side close to the substrate 6. In fact, when the side close to the substrate 6 is P-type doped, the manufacturing steps are basically the same, and only the positive and negative polarities of the circuit on the driving substrate 1 need to be changed.

[0116] S602. Refer to Figure 20 of (b). Grow epitaxial material in the holes 121, and an epitaxial structure 3 is formed in each hole 121. In practical applications, a large number of holes 121 can be formed on the same substrate 6, and multiple epitaxial structures 3 can be obtained. Figure 20 Only two epitaxial structures 3 are shown as an example in . In this example, the epitaxial structure 3 is obtained through the holes 121 formed by the flat sacrificial layer 12, without etching the epitaxial material, avoiding the damage caused by etching, and can improve the radiation efficiency in some implementation processes.

[0117] S603. Refer to Figure 20 of (c). Sequentially prepare a current spreading layer 8 and a first bonding layer 9 on the surface of the epitaxial structure 3. The current spreading layer 8 and the first bonding layer 9 are disposed over the entire surface of the epitaxial wafer and are in contact with the epitaxial structure 3. Among them, the current spreading layer 8 is close to the epitaxial structure 3, and the first bonding layer 9 is disposed on the current spreading layer 8. In this example, the first bonding layer 9 includes a conductive metal material, and the current spreading layer 8 is indium tin oxide as an example, and its material is not actually limited.

[0118] S604. Refer to Figure 20 of (d). Sequentially prepare a current spreading layer 8 and a second bonding layer 10 on the surface of the driving substrate 1. The current spreading layer 8 is connected to the driving circuit of the driving substrate 1 through the contact 11. In this example, the second bonding layer 10 includes a conductive metal material, and the current spreading layer 8 is indium tin oxide as an example, and its material is not actually limited.

[0119] S605. Refer to Figure 20In step (e), the epitaxial wafer obtained in step S603 and the driving substrate 1 obtained in step S604 are integrally bonded through the first bonding layer 9 and the second bonding layer 10. The first bonding layer 9 and the second bonding layer 10 are fused to form a conductive layer 2 during the bonding process under pressure and / or heating. A plurality of contacts 11 are formed on the driving substrate 1 in this example, and the center pitch of the contacts 11 is designed to be consistent with the spacing of the epitaxial structure 3 of the light-emitting module. For the convenience of description, only some of the contacts 11 are shown in this application. As Figure 20 taking (e) as an example, for the convenience of description, Figure 20 the rightmost contact 11 in (e) is the N pole, and the remaining contacts 11 shown in the figure are the P poles. The actual number of specific contacts 11 and the positive and negative electricities are not limited.

[0120] S606. Refer to Figure 21 figure (f). Remove the substrate 6 on which the epitaxial material is grown. The substrate 6 in this example is a sapphire substrate and can be removed by laser lift-off. A solid-state laser can be used as the laser for laser lift-off. After the laser lift-off is completed, the removal of gallium metal can be carried out synchronously. It should be noted that in some implementation processes, in order to match the epitaxial characteristics, after the substrate 6 is removed, the buffer layers such as the native sputter AlN (aluminum nitride thin film buffer layer) and the unintentionally doped gallium nitride layer of the gallium nitride material are also etched away to expose the N-type doped gallium nitride, and then the subsequent chip manufacturing process is carried out. For the convenience of description, some structures and steps are omitted in the figure of this example.

[0121] S607. Refer to Figure 21 figure (g). Remove the planar sacrificial layer 12. The removal method of the planar sacrificial layer 12 can be selected according to the materials used. Exemplarily, wet etching can be used for removal. In some other implementation processes, the same structure can also be formed by the implementation manners of the foregoing steps S301 to S306, which will not be elaborated in this example.

[0122] S608. Refer to Figure 21 figure (h). Set the first photoresist material 401. In this example, the first photoresist material 401 is negative, and the set thickness of the first photoresist material 401 can be relatively thin so that the area corresponding to the conductive layer 2 is more easily exposed. The first photoresist material 401 can be set on this side of the epitaxial structure 3 through processes including but not limited to spin coating.

[0123] S609. Refer to Figure 21(i), the first photoresist material 401 is exposed and developed to form a pattern, resulting in the first photoresist layer 41. In this example, the first photoresist layer 41 completely covers each epitaxial structure 3 and extends a certain range around each epitaxial structure 3, and its pattern corresponds to the pattern of the first electrode 21 of the light-emitting chip. The first photoresist material 401 between adjacent epitaxial structures 3 is removed, exposing the area corresponding to the conductive layer 2.

[0124] S610. Refer to Figure 21 (j), a second photoresist material 402 is provided. In this example, the second photoresist material 402 is positive. The second photoresist material 402 can be provided on this side of the epitaxial structure 3 through processes including but not limited to spin coating. After the second photoresist material 402 is exposed and developed to form a pattern, the second photoresist layer 42 is formed. In this embodiment, the developing conditions of the first photoresist material 401 and the second photoresist material 402 are different.

[0125] S611. Refer to Figure 21 (k), after the second photoresist material 402 is exposed and developed to form a pattern, the second photoresist layer 42 is formed. In this example, the projection of the pattern of the second photoresist layer 42 onto the driving substrate 1 is the same as the projection of the pattern of the first photoresist layer 41 onto the driving substrate 1. The second photoresist material 402 between adjacent epitaxial structures 3 is removed, exposing the area corresponding to the conductive layer 2. In other examples, the patterns of the first photoresist layer 41 and the second photoresist layer 42 can be configured to be not completely the same.

[0126] Since the first photoresist layer 41 has already been formed on the epitaxial structure 3 for protection, the second photoresist material 402 can be set thicker. Even after a long development time, it will not have an obvious impact on the first photoresist layer 41. Therefore, in this example, the second photoresist material 402 is set thicker than the first photoresist material 401, and the formed second photoresist layer 42 is also thicker to provide sufficient protection performance for the epitaxial structure 3. The specific thicknesses of the first photoresist layer 41 and the second photoresist layer 42 can be set according to the actual situation. Moreover, the above manufacturing method can also be effectively applied to products with a large aspect ratio between epitaxial structures 3 and is suitable for light-emitting modules with densely arranged light-emitting chips.

[0127] The structure formed in the foregoing steps uses a photoresist material to form the mask layer 4, which can be more easily removed completely in the subsequent manufacturing process flow, facilitating the simplification of the structure of the light-emitting module.

[0128] S612. Refer to Figure 22 (l), based on the foregoing Figure 21In the fabricated structure of the example, the conductive layer 2 is dry-etched under the protection of the mask layer 4, and the conductive layer 2 corresponding to each epitaxial structure 3 is etched and disconnected to form a plurality of first electrodes 21. In this example, the first electrodes 21 correspond to the epitaxial structures 3 one by one. During the etching process, the etched metal is redeposited on the mask layer 4 to form an attachment 5, and the mask layer 4 isolates the attachment 5 from the epitaxial structure 3.

[0129] S613. Refer to Figure 22 (m), after the etching of the area to be etched of the conductive layer 2 is completed, the mask layer 4 can be removed. A photoresist removal device can be used to remove the mask layer 4. Additionally, the remaining attachment 5 can also be washed away by equipment such as a gold stripper. After the mask layer 4 is removed, the sides of each epitaxial structure 3 and the first electrodes 21 are exposed.

[0130] S614. Refer to Figure 22 (n), an insulating planarization layer 13 is fabricated. Its materials include but are not limited to aluminum oxide and silicon dioxide, and can be formed by processes including but not limited to ALD (Atomic Layer Deposition) and PECVD (plasma-enhanced chemical vapor deposition). The insulating planarization layer 13 can insulate and protect the exposed epitaxial structures 3 and the first electrodes 21, and fill the spaced areas between adjacent epitaxial structures 3 to form a relatively flat surface. In some embodiments, the insulating planarization layer 13 may not completely fill the spaced areas of the epitaxial structures 3 and can be formed into other relatively gentle shapes, which can also facilitate the setting of subsequent structures.

[0131] S615. Refer to Figure 22 (o), a second electrode 14 is formed on the epitaxial structure 3. The second electrode 14 in this example is a common electrode and is connected to multiple epitaxial structures 3 simultaneously. In this embodiment, the second electrode 14 is an N pole, and the second electrode 14 is connected to the contact 11 on the leftmost side (in the illustrated direction) of the driving substrate 1 through a conductive via or wire bonding. In some implementation processes, to achieve better conductive effects, before forming the second electrode 14, an ohmic contact layer (not shown in the figure) is further formed on the epitaxial structure 3. The material of the ohmic contact layer can be indium tin oxide, but is not limited thereto. For example, other materials with transparent conductivity and capable of forming an ohmic contact with gallium nitride can also be used, such as graphene, indium zinc oxide, and thin metal film layers. The second electrode 14 can be connected to the epitaxial structure 3 through the ohmic contact layer.

[0132] In practical applications, other structures can also be further provided. For example, an insulating material can be further provided on the surface of the second electrode 14 for protection. For another example, an optical structure such as a lens can be provided at the position corresponding to the light-emitting chip. The present embodiment does not limit other structures in the light-emitting module.

[0133] The light-emitting module formed by the above steps has a simpler structure and no residue of the attachment 5 formed by metal re-deposition, and has good quality in some implementation processes.

[0134] It should be understood that the application of the present application is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present application.

Claims

1. A manufacturing method of a light-emitting module, characterized in that, Including: Providing a driving substrate; Providing a conductive layer on the driving substrate and a plurality of epitaxial structures electrically connected to the conductive layer; Providing a mask layer on the epitaxial structure, the mask layer at least covering and protecting the epitaxial structure and exposing the area of the conductive layer to be etched; wherein, the mask layer includes a first photoresist layer covering the epitaxial structure and a second photoresist layer provided on the first photoresist layer, and the second photoresist layer has different developing conditions from the first photoresist layer; Etching the area of the conductive layer to be etched under the protection of the mask layer to form the conductive layer into a plurality of first electrodes; wherein, when etching the conductive layer, an attachment is formed on the mask layer; Removing the mask layer.

2. The manufacturing method of the light-emitting module according to claim 1, characterized in that, The thickness of the first photoresist layer is less than the thickness of the second photoresist layer.

3. The manufacturing method of the light-emitting module according to claim 1, wherein, The edge of the mask layer is configured to be ramp-shaped or stepped.

4. The manufacturing method of the light-emitting module according to any one of claims 1-3, characterized in that Among the first photoresist layer and the second photoresist layer, one is a positive photoresist and the other is a negative photoresist.

5. The manufacturing method of the light-emitting module according to claim 4, characterized in that, The step of providing a mask layer on the epitaxial structure includes: Providing a negative first photoresist material; Exposing and developing the first photoresist material to form the first photoresist layer; Providing a positive second photoresist material; Exposing and developing the second photoresist material to form the second photoresist layer, and the developing conditions when developing the second photoresist material are different from the developing conditions when developing the first photoresist material.

6. The manufacturing method of the light-emitting module according to claim 1, characterized in that, The step of providing a plurality of epitaxial structures electrically connected to the conductive layer on the conductive layer includes: Providing an epitaxial wafer, the epitaxial wafer including a substrate and an epitaxial layer formed on the substrate; Providing a first bonding layer on the epitaxial layer; Providing a second bonding layer on the driving substrate; Bonding the epitaxial wafer to the driving substrate so that the first bonding layer and the second bonding layer are bonded to form the conductive layer; Removing the substrate; Forming the epitaxial layer into the plurality of epitaxial structures.

7. The manufacturing method of the light-emitting module according to claim 1, characterized in that The step of providing a plurality of epitaxial structures electrically connected to the conductive layer on the conductive layer includes: Providing an epitaxial wafer, the epitaxial wafer including a substrate, a plurality of the epitaxial structures provided on the substrate, and a planar sacrificial layer filled between the epitaxial structures; Providing a first bonding layer electrically connected to each of the epitaxial structures on the epitaxial wafer; Providing a second bonding layer on the driving substrate; Bonding the epitaxial wafer to the driving substrate so that the first bonding layer and the second bonding layer are bonded to form the conductive layer; Removing the substrate; Removing the planar sacrificial layer.

8. The manufacturing method of the light-emitting module according to claim 1, characterized in that, After removing the mask layer, further including: Forming a second electrode on a side of the epitaxial structure away from the first electrode.

9. The manufacturing method of the light-emitting module according to claim 8, characterized in that, The step of forming a second electrode on a side of the epitaxial structure away from the first electrode includes: Providing an insulating planar layer on the driving substrate to fill between the epitaxial structures, the insulating planar layer covering the sidewalls of the epitaxial structures and exposing a side of the epitaxial structures away from the driving substrate; Deposit the material of the second electrode on the insulating flat layer and the epitaxial structure to form the second electrode. One second electrode corresponds to a plurality of the epitaxial structures, and the second electrode is connected to the driving substrate.

10. A light-emitting module, characterized in that, The light-emitting module includes a driving substrate and a light-emitting chip disposed on the driving substrate. The light-emitting module is obtained by the manufacturing method of the light-emitting module according to claim 8 or 9.

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