CN117691030A

CN117691030A - Light-emitting module and display device

Info

Publication number: CN117691030A
Application number: CN202311566288.4A
Authority: CN
Inventors: 王杰凌; 时军朋; 林振端; 余长治; 徐宸科
Original assignee: Quanzhou Sanan Semiconductor Technology Co Ltd
Current assignee: Quanzhou Sanan Semiconductor Technology Co Ltd
Priority date: 2023-11-22
Filing date: 2023-11-22
Publication date: 2024-03-12

Abstract

The application discloses light emitting module and display device when forming the light emitting module of this application, forms first wiring layer in light emitting component and filling layer top, and first wiring layer is as the seed layer of growing conductive pad. A first protective layer is formed over the first wiring layer. And forming a second wiring layer over the first protective layer and at edge portions of the sidewalls and the bottom of the first opening, whereby the second wiring layer entirely covers the filling layer and the light emitting element except for the region of the first opening and communicates with the first wiring layer. When the conductive pad is formed, the electroplating process is performed by electrifying the second wiring layer, and the conductive pad is grown in the first opening. Because the second wiring layer is covered by the whole layer and is formed above the first protective layer, the second wiring layer has good smooth surface and continuity, and can realize better conductive effect, thereby improving the uniformity of the electroplated conductive pad and being beneficial to improving the electrical property of the device.

Description

Light-emitting module and display device

Technical Field

The present disclosure relates to semiconductor technology, and particularly to a light emitting module and a display device.

Background

Light emitting diodes are widely used in various fields such as display devices, lamps for vehicles, general illumination lamps, etc. due to their characteristics of high reliability, long life span, and low power consumption, for example, they can be used as backlight sources for various display devices. In order to provide effective mechanical protection for the light emitting diode, the light emitting diode is often packaged and formed into a light emitting module. In a light emitting module including a plurality of light emitting diodes (e.g., a plurality of micro-LEDs), a pad is generally formed through a seed layer by a plating method. Since the seed layer is usually formed on the surface of the filling layer in the light emitting module, and the filling layer is usually a material layer with rough surface, the thickness of the seed layer is usually smaller, so that the surface of the seed layer is also an uneven surface, and problems such as vertical lines may occur. At this time, when the bonding pad grows through the seed layer, the problem of uneven thickness of the bonding pad occurs, and the electrical performance of the bonding pad and the electrical performance of the whole light-emitting module are affected.

Therefore, a scheme capable of improving uniformity of the conductive pads of the light emitting module is urgently needed.

Disclosure of Invention

The application provides a light emitting module and a display device aiming at the problems of the light emitting module in the prior art. The uniformity problem of the conductive bonding pad of the light-emitting module is solved, and the electrical performance of the device is improved.

An embodiment of the present application provides a light emitting module, which includes:

a plurality of light emitting elements arranged at intervals;

a filling layer filled between adjacent light emitting elements;

a wiring layer located above the light emitting element and the filling layer and electrically connected with the light emitting element;

a conductive pad formed on a side of the wiring layer away from the light emitting element and electrically connected to the wiring layer;

wherein the wiring layer includes a first wiring layer and a second wiring layer, the second wiring layer is located between the first wiring layer and the conductive pad, and the second wiring layer is located below an edge region of the conductive pad.

Yet another embodiment of the present application provides a display device, which includes a circuit substrate, and a plurality of light emitting units fixed to the circuit substrate, the light emitting units including the light emitting module described herein.

The luminous module and the display device have the following beneficial effects:

when the light-emitting module is formed, a first wiring layer is formed above the light-emitting element and the filling layer, and the first wiring layer is used as a seed layer for growing the conductive pad. A first protective layer is formed over the first wiring layer, the first protective layer covering the entire filler layer and all light emitting elements, and a first opening is formed in a region where a conductive pad is to be formed for each light emitting module. And forming a second wiring layer over the first protective layer and at edge portions of the sidewalls and the bottom of the first opening, whereby the second wiring layer entirely covers the filling layer and the light emitting element except for the region of the first opening and communicates with the first wiring layer. When the conductive pad is formed, the electroplating process is performed by electrifying the second wiring layer, and the conductive pad is grown in the first opening. Because the second wiring layer is covered by the whole layer, a better conductive effect can be realized; in addition, the second wiring layer is formed above the first protection layer, has good surface flatness, and can improve the uniformity of current flowing into the second wiring layer, so that the uniformity of the electroplated conductive pad is improved, the conductive pad has a flat outer surface, subsequent welding is facilitated, and meanwhile, the electrical property of a device is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a light emitting module according to an embodiment of the disclosure.

Fig. 2 shows a partial enlarged view of the portion a in fig. 1.

FIG. 3 is a schematic top view of the structure along L1-L1 in FIG. 1.

Fig. 4 is a schematic top view of an alternative embodiment of the first embodiment, taken along L1-L1 in fig. 1.

Fig. 5 is a schematic structural diagram of a light emitting module according to an alternative embodiment of the first embodiment.

Fig. 6 is a schematic structural diagram of a light emitting module according to another alternative embodiment of the first embodiment.

Fig. 7 is a flowchart of a method for manufacturing a light emitting module according to a second embodiment of the present application.

Fig. 8 is a schematic view showing a structure in which a light emitting element is fixed on a transparent layer.

Fig. 9 shows a schematic structure for forming a filling layer.

Fig. 10 is a schematic diagram showing a structure of forming a first seed layer.

Fig. 11 is a schematic top view of the structure of fig. 10.

Fig. 12 is a schematic view of a structure for forming a first protective layer over the structure shown in fig. 10.

Fig. 13 is a schematic top view of the structure of fig. 12.

Fig. 14 is a schematic view showing a structure of forming a second protective layer over the structure shown in fig. 12.

Fig. 15 is a schematic top view of the structure of fig. 14.

Fig. 16 is a schematic view showing a structure in which a second seed layer is formed over the structure shown in fig. 14.

Fig. 17 is a schematic diagram showing a structure in which the second protective layer and a portion of the second seed layer thereon shown in fig. 16 are removed.

Fig. 18 is a schematic top view of the structure of fig. 17.

Fig. 19 is a schematic view showing a structure of forming a mask layer over the structure shown in fig. 17.

Fig. 20 is a schematic top view of the structure of fig. 19.

Fig. 21 shows a schematic diagram of a structure for electroplating conductive pads over the structure shown in fig. 19.

Fig. 22 is a schematic structural diagram of a light emitting device according to a third embodiment of the present disclosure.

Illustration of:

10. a light emitting module; 11. a transparent layer; 111, a first transparent layer; 112. a second transparent layer; 12. a filling layer; 13. a first protective layer; 130. a first opening; 14. a first wiring layer; 140. a conductive pad forming region; 141. a first sub-wiring; 142. a second sub-wiring; 143. a third sub-wiring; 144. a fourth sub-wiring; 145. a connection part; 15. a light emitting element; 151. a first light emitting element; 152. a second light emitting element; 153. a third light emitting element; 1501. a first electrode 1501; 1502. a second electrode 1502; 16. a second wiring layer; 161. a first portion; 162. a second portion; 17. an encapsulation layer; 18. a conductive pad; 181. a first bonding pad; 182. a second bonding pad; 183. a third bonding pad; 184. a fourth pad; 1801. a conductive layer; 1802. a protective layer; 1803. an adhesive layer 1803; 1804. a eutectic layer; 19. a mask layer; 190, a second opening; 20. a second protective layer; 30. a display device; 301. a circuit substrate; 302. and a light emitting unit.

Detailed Description

Other advantages and effects of the present application will become apparent to those skilled in the art from the present disclosure, when the following description of the present application is taken in conjunction with the accompanying drawings. The present application may be carried out or operated in different embodiments, and various modifications or changes may be made in the details of the application based on different points of view and applications without departing from the spirit of the application.

In the prior art, in the packaging process of the LED light emitting module, a conductive bonding pad needs to be formed through a seed layer. Since the seed layer is formed directly over the light emitting element and the filling layer between the light emitting elements, the filling layer is usually formed as a material layer with rough surface, which causes the seed layer to be also formed as a rough and uneven surface, and may also cause problems such as vertical lines. Since the seed layer is thin, the roughness of the surface and the vertical lines directly affect the conductivity, and thus the structure of the conductive pad formed by electroplating may be affected, for example, the conductive pad formed by electroplating may have thicker edge regions, thinner middle regions, different heights, and uneven surfaces. The structure has the advantages that the stability, the uniformity and the like of the electrical performance of the conductive bonding pad are affected, and the problems of poor electrical performance and the like of the light-emitting module are caused.

To the above-mentioned problem, the present application provides a light emitting module, which at least includes:

a plurality of light emitting elements arranged at intervals;

a filling layer filled between adjacent light emitting elements;

The second wiring layer is formed so that the uniformity of current is improved when the conductive bonding pad is formed by electroplating, so that the growth uniformity of the conductive bonding pad is improved, and the conductive bonding pad with a flat surface and no level difference is obtained, thereby improving the stability of the electrical performance of the light-emitting module and the yield thereof.

Optionally, the conductive pad includes a portion in contact with the second wiring layer and a portion in contact with the first wiring layer.

Optionally, the light emitting module further includes: and a first protection layer over the first wiring layer, the first protection layer forming a first opening in a region where the conductive pad is located, the second wiring layer including a first portion formed at a bottom of the first opening, and a second portion formed over the first protection layer at a periphery of the first opening, the conductive pad filling the first opening and being formed over the second wiring layer.

The first protective layer is formed above the second wiring layer, the second wiring layer is formed above the first protective layer, and the surface evenness and the continuity of the second wiring layer can be improved by forming the first protective layer, so that the second wiring layer has good electric conduction performance, the uniformity of current in the electroplating process is improved, and the structural uniformity of the electric conduction pad formed by electroplating is improved.

Optionally, the thickness of the first protective layer is 1 μm to 7 μm.

Optionally, at an edge of the first wiring layer, a width of the first wiring layer covered by the first protective layer is less than 20 μm.

The thickness and coverage of the first protective layer can ensure that the first protective layer forms a good flat surface, and a first opening suitable for the growth of the conductive pad is reserved.

Optionally, in a longitudinal section direction of the conductive pad, a width of the first portion is 2 μm or more and less than or equal to 1/3 of a width of the conductive pad.

Optionally, in a longitudinal section direction of the conductive pad, a width of the second portion is 2 μm or more and less than or equal to 1/3 of a width of the conductive pad.

The first portion and the second portion of the second wiring layer form a continuous structure, wherein the first portion is connected to the first wiring layer, and the first portion ensures that a current applied from the second wiring layer can reach the first wiring layer during electroplating to complete the process of electroplating the conductive pad. The width of the second portion is not too large to ensure that the conductive pads can be grown on the first wiring layer, nor too small to ensure good electrical conductivity.

Optionally, the filling layer covers at least the active layer of the light emitting element. The filling layer may be formed at the same height as the light emitting elements or may be lower than the light emitting elements, but at least covers the active layer of the light emitting elements, and is a black filling layer, so that light radiated by adjacent light emitting elements can be prevented from cross-talk with each other, and the light emitting effect of each light emitting element can be ensured.

Optionally, the thickness of the light emitting element is 15 μm or less, and the pitch between adjacent light emitting elements is less than 50 μm.

The light-emitting elements are micro-LED chips, and the distance can ensure that mutual interference between each light-emitting element can not occur.

Optionally, the light emitting module further includes an encapsulation layer, where the encapsulation layer is located above the first protection layer and formed on the periphery of the conductive pad, and the thickness of the encapsulation layer is greater than 20 μm.

Optionally, the encapsulation layer is a transparent insulation layer or a black insulation layer.

The packaging layer is formed above the first protective layer and around the conductive bonding pad, so that the whole light-emitting module and the conductive bonding pad can be protected from external water vapor, impurities and the like, and the performance integrity of the light-emitting module is ensured. Meanwhile, the packaging layer can be formed into a black insulating layer so as to further absorb light radiated by the self-luminous element, ensure that the light can not be emitted from the non-light-emitting surface without safety, and further ensure the light-emitting effect of the light-emitting module.

Optionally, the light emitting module further includes a transparent layer, the light emitting element is disposed above the transparent layer, the transparent layer includes a first transparent layer and a second transparent layer, the second transparent layer is interposed between the first transparent layer and the light emitting element, a thickness of the first transparent layer is greater than 10 μm, and a thickness of the second transparent layer is less than 10 μm.

The first transparent layer may be a transparent substrate, such as a sapphire substrate, and the second transparent layer may be a die bonding layer, where the thickness of the first transparent layer can ensure support for the entire light emitting module and ensure sufficient light transmittance, and the thickness of the second transparent layer ensures that the light emitting element is stably fixed on the first transparent layer, and the thickness of the second transparent layer also does not affect the light emitting effect of the light emitting module.

Alternatively, the plurality of light emitting elements includes a red light chip, a green light chip, and a blue light chip.

Optionally, the thickness of the first wiring layer is between 50nm and 1000nm. The thickness of the first wiring layer can ensure good electrical contact of the rest of the light emitting elements, and can realize the electroplating process of the conductive pad.

Optionally, the thickness of the second wiring layer is between 50nm and 1000nm.

Optionally, the first wiring layer is a Ti and Cu metal layer.

Optionally, the second wiring layer is a metal layer formed of Ti and/or Cu.

The second wiring layer is made of the metal material with good conductivity and adhesiveness and easy to remove later, the thickness of the metal material can ensure that the second wiring layer forms a uniform and smooth continuous structure, good conductivity of the metal material is ensured, meanwhile, the second wiring layer near the first opening can not influence the growth of the conductive bonding pad, and the conductive bonding pad forms a structure with a smooth surface.

Optionally, the conductive pad includes a conductive layer, an adhesive layer, and a protective layer, where the thickness of the conductive layer is 20 μm or more, the thickness of the adhesive layer is 3 μm to 5 μm, and the thickness of the protective layer is 25nm to 50nm.

Optionally, the conductive pad includes a conductive layer, an adhesive layer, and a eutectic layer, where the thickness of the conductive layer is 20 μm or more, the thickness of the adhesive layer is 3 μm to 5 μm, and the thickness of the eutectic layer is 10nm to 50nm.

Optionally, the conductive pad includes a conductive layer, an adhesive layer, a eutectic layer and a protective layer, wherein the thickness of the conductive layer is greater than or equal to 20 μm, the thickness of the adhesive layer is between 3 μm and 5 μm, the thickness of the eutectic layer is between 10nm and 50nm, and the thickness of the protective layer is between 25nm and 50nm.

The conductive pad is formed as a thick pad having a thickness of 20 μm or more, and as described above, the conductive pad is formed as a pad having a flat structure without level differences, thereby ensuring good performance of the conductive pad.

Optionally, the light emitting module further includes a packaging layer, the packaging layer is filled in the periphery of the conductive pad, and a surface of the packaging layer far away from the wiring layer is flush with a surface of the conductive layer far away from the wiring layer.

The packaging layer protects the first wiring layer, the second wiring layer and the light-emitting element in the light-emitting module from external pollution or damage, and simultaneously ensures that the conductive part of the conductive bonding pad is not damaged, and ensures good electrical performance of the light-emitting module.

Optionally, the thickness of the conductive pad is greater than 20 μm.

A further aspect of the present application provides a display device including a circuit substrate, and a plurality of light emitting units fixed to the circuit substrate, the light emitting units including the light emitting module provided herein.

The display device comprises the light-emitting module provided by the application, so that the display device has good display effect and reliability.

Example 1

The present embodiment provides a light emitting module, as shown in fig. 1, the light emitting module 10 includes a plurality of light emitting elements 15 arranged at intervals, a filling layer 12 filled between adjacent light emitting elements 15, a wiring layer above the light emitting elements 15 and the filling layer 12 and electrically connected to the light emitting elements 15, and a conductive pad 18 formed on a side of the wiring layer away from the light emitting elements 15, wherein the conductive pad 18 is electrically connected to the wiring layer.

In alternative embodiments, the light emitting element 15 mainly refers to a light emitting diode of the order of micrometers, the width and length of which are in the range of 2 μm to 5 μm, 5 μm to 10 μm, 10 μm to 20 μm, 20 μm to 50 μm or 50 μm to 100 μm, and the thickness of which is in the range of 2 μm to 15 μm, further 5 μm to 10 μm. Referring to fig. 1 and 3, in the present embodiment, the light emitting module 10 includes a first light emitting element 151, a second light emitting element 152, and a third light emitting element 153.

Specifically, each light emitting element 15 includes a semiconductor stacked layer, which may include a first semiconductor layer, a second semiconductor layer, and an active layer disposed therebetween in order, wherein the first semiconductor layer is an N-type semiconductor layer, the second semiconductor layer is a P-type semiconductor layer, or the first semiconductor layer is a P-type semiconductor layer, the second semiconductor layer is an N-type semiconductor layer; the active layer is a multi-layered quantum well layer that can radiate red light or green light or blue light. The N-type semiconductor layer, the multi-layer quantum well layer, and the P-type semiconductor layer are only basic constituent units of the light emitting element 15, and the light emitting element 15 may further include other functional structure layers having an optimization effect on the performance of the light emitting element 15.

The first light emitting element 151, the second light emitting element 152, and the third light emitting element 153 respectively radiate light rays of different wavelength ranges, for example, the first light emitting element 151 radiates blue light rays, the second light emitting element 152 radiates green light rays, and the third light emitting element 153 radiates red light rays, and the light emitting module 10 of the present embodiment is formed as an RGB package module. In one embodiment, the different light emitting elements 15 have different semiconductor stacked layers so as to directly radiate light in different wavelength ranges, and specific materials of the semiconductor stacked layers are selected according to the wavelength of the radiated light, which includes but is not limited to aluminum gallium arsenide, gallium arsenide phosphide, aluminum gallium indium phosphide, gallium nitride, indium gallium nitride, zinc selenide, or gallium phosphide. In another embodiment, the different light emitting elements 15 may have the same semiconductor stacked layers, for example, the semiconductor stacked layers in the first light emitting element 151, the second light emitting element 152, and the third light emitting element 153 each radiate blue light, and a wavelength conversion layer is disposed on the light emitting surface of the second light emitting element 152 to convert the radiated blue light into green light, and a wavelength conversion layer is disposed on the light emitting surface of the third light emitting element 153 to convert the radiated blue light into red light.

Referring also to fig. 3, each light emitting element 15 further includes a first electrode 1501 and a second electrode 1502. The first electrode 1501 is electrically connected to the first semiconductor layer, and the second electrode 1502 is electrically connected to the second semiconductor layer. Alternatively, the thickness difference between the light emitting elements 15 is less than or equal to 5 μm, which can effectively improve the transfer yield of the light emitting module 10 onto the transparent layer 11 described later, so as to improve the light emitting effect of the light emitting module 10.

Referring also to fig. 1, the filling layer 12 is filled to a gap between adjacent light emitting elements 15 or formed around a sidewall of each light emitting element 15 to electrically isolate adjacent light emitting elements 15 while preventing color mixing or light interference between the adjacent light emitting elements 15 to improve the contrast of the light emitting module 10. The filler layer 12 is provided as a black glue layer that absorbs light.

Since the thickness of the light emitting element 15 ranges from 2 to 15 μm and the interval between adjacent light emitting elements 15 is less than 50 μm, the filling layer 12 is filled with a material having good fluidity and then cured. The particle size of the black filling component filled in the filling layer 12 is preferably not more than 1/10 of the thickness of the light emitting element 15, which can avoid the problem that the coating effect of the filling layer 12 on the light emitting element 15 is poor due to the excessively large particle size of the black filling component, and thus the contrast of the light emitting module 10 is affected. The filler layer 12 may specifically be a member formed by dispersing a black filler component having a particle diameter of not more than 1 μm in a transparent or translucent material such as silica gel, epoxy resin, polyimide, low temperature glass, polysiloxane, polysilazane, etc., and the black filler component in the filler layer 12 includes, but is not limited to, carbon black, titanium nitride, iron oxide, ferroferric oxide, iron powder, etc. The particle size of the black filler is preferably in the range of 10 to 100nm, alternatively 100 to 200nm, alternatively 200 to 300nm, alternatively 300 to 500nm. Black dye may also be used for the filler layer 12.

In order to ensure that no color mixing or interference between adjacent light emitting elements 15 occurs, the filling layer 12 covers at least above the active layer of the light emitting element 15, and further covers all the side walls of the light emitting element 15. As an alternative embodiment, the thickness of the filling layer 12 may be greater than that of the light emitting element 15, and light interference caused by light leakage at the bottom of the light emitting element 15 may be prevented. The thickness of the filler layer 12 is preferably less than 15 μm.

Referring again to fig. 1 and 2, a wiring layer is formed over the plurality of light emitting elements 15 and the filler layer 12, and is electrically connected to the light emitting elements 15. In the embodiment, the wiring layers include the first wiring layer 14 and the second wiring layer 16, wherein the first wiring layer 14 is formed over the light emitting element 15 and the filler layer 12, electrically connected to the light emitting element 15, the second wiring layer 16 is formed over the first wiring layer 14, and the first protective layer 13 is further formed between the first wiring layer 14 and the second wiring layer 16.

Referring to fig. 3, the first wiring layer 14 includes a number of sub-wirings. In an alternative embodiment, as shown in fig. 3, the first wiring layer 14 includes a first sub-wiring 141, a second sub-wiring 142, a third sub-wiring 143, and a fourth sub-wiring 144, wherein the first sub-wiring 141 serves as a common wiring, first electrodes 1501 of the first light emitting element 151, the second light emitting element 152, and the third light emitting element 153 are connected in series, a second electrode 1502 of the first light emitting element 151 is connected to the second sub-wiring 142, a second electrode 1502 of the second light emitting element 152 is connected to the third sub-wiring 143, and a second electrode 1502 of the third light emitting element 153 is connected to the fourth sub-wiring 144.

Alternatively, the first sub-wiring 141 serves as a common wiring, the second electrode 1502 of the first light emitting element 151, the second light emitting element 152, and the third light emitting element 153 are connected in series, the first electrode 1501 of the first light emitting element 151 is connected to the second sub-wiring 142, the first electrode 1501 of the second light emitting element 152 is connected to the third sub-wiring 143, and the first electrode 1501 of the third light emitting element 153 is connected to the fourth sub-wiring 144. The first wiring layer 14 may have a single-layer or multi-layer structure made of at least one material of titanium, copper, chromium, nickel, gold, platinum, aluminum, titanium nitride, tantalum, or the like by sputtering, vapor deposition, or the like. In this embodiment, the first wiring layer 14 is a composite metal layer formed of Ti and Cu, and the thickness of the first wiring layer 14 is 50nm to 1000nm, for example, 100nm, 200nm, 500nm, 600nm, 800nm, or the like. The material of the first wiring layer 14 is chosen to ensure good adhesion to the filler layer 12 and its thickness is set such that it ensures good growth of the conductive pads while enabling good electrical connection to the light emitting element.

As shown in fig. 3, the first electrode 1501 of the first, second, and third light emitting elements 151, 152, and 153 are distributed on the same side, and the second electrode 1502 is distributed on the same side. In another alternative embodiment of the present embodiment, the first electrode 1501 of one light emitting element among the first light emitting element 151, the second light emitting element 152 and the third light emitting element 153 is disposed on the opposite side of the first electrodes 1501 of the other two light emitting elements 15, and correspondingly, the second electrodes 1502 thereof are disposed on the opposite side of the second electrodes 1502 of the other two light emitting elements 15. For example, as shown in fig. 4, in which two electrodes of the second light emitting element 152 are disposed on opposite sides of two electrodes of the first light emitting element 151 and the third light emitting element 153, thereby bonding pads connecting the second electrodes 1502 of the light emitting elements 15 are located on the same side as the second electrodes 1502 of the corresponding light emitting elements 15, thereby reducing corner arrangement of wirings, further avoiding the problem of too narrow line width between adjacent wirings, and improving reliability of the light emitting device of small size.

Referring to fig. 2, the first protective layer 13 is located above the first wiring layer 14, i.e., covers the first wiring layer 14 and is located above the filling layer 12 to which the first wiring layer 14 is exposed. The first protective layer 13 may be a transparent insulating layer or a black insulating layer, such as SiO ₂ The inorganic insulating material layer such as a layer or SiN layer may be an organic insulating material layer such as silica gel or silicone. The thickness of the first protective layer 13 is 1 μm to 7 μm, alternatively 1 μm, 3 μm, 4 μm, 5 μm, 7 μm, which can ensure that the first protective layer 13 is a structural layer with a flat surface, and can ensure the dimensional characteristics of the light emitting module 10 without increasing the overall thickness of the light emitting module 10. As also shown in fig. 2, the first protective layer 13 forms a first opening 130 above the first wiring layer 14, where the first opening 130 is a location area where the conductive pad 18 is formed later, and the first opening 130 exposes the first wiring layer 14 to facilitate formation of the conductive pad 18. Referring to fig. 2, at the position where the first opening 130 is formed, at the edge position of the first wiring layer 14, the width d3 of the first wiring layer 14 covered by the first protective layer 13 is less than 20 μm; further, the particle size may be 5 μm to 10. Mu.m, for example, 5 μm, 7 μm, 8 μm, or 10. Mu.m. The cover width ensures that the bottom of the formed conductive pad has sufficient contact area with the first wiring layer 14, ensuring that the conductive pad can be grown well in the formed first opening 130.

The second wiring layer 16 is formed around the first opening 130, and the second wiring layer 16 may be a single-layer or multi-layer structure made of at least one material selected from titanium, copper, chromium, nickel, gold, platinum, aluminum, titanium nitride, tantalum, or the like, by sputtering, vapor deposition, or the like, and in this embodiment, the second wiring layer is a composite metal layer formed of Ti and Cu. The thickness of the second wiring layer 16 may be the same as or different from the thickness of the first wiring layer 14. For example, the thickness of the second wiring layer 16 is 100nm to 1000nm, and may be, for example, 100nm, 200nm, 500nm, 700nm, 900nm, or 1000nm. In this embodiment, the thickness of the Ti metal layer is about 100nm, and the thickness of the Cu metal layer is about 800 nm.

Specifically, the second wiring layer 16 as shown in fig. 2 includes a first portion 161 formed at the bottom of the first opening 130, and a second portion 162 formed over the first protective layer 13 at the periphery of the first opening 130. The width d1 of the first portion 161 of the second wiring layer 16 is 2 μm or more and 1/3 or less of the width of the conductive pad 18. This width ensures good electrical connection of the second wiring layer 16 to the first wiring layer 14 within the first opening 130 without overly covering the first wiring layer 14 within the first opening 130, ensuring that the conductive pad 18 is formed well on the first wiring layer 14. The width d2 of the second portion 161 is 2 μm or more and 1/3 or less of the width of the conductive pad 18, and the width of the second portion 162 is set to ensure that the conductive pads 18 are well formed, while ensuring that the spacing between adjacent conductive pads 18 is not too small, and ensuring electrical isolation from each other.

Referring again to fig. 1, the conductive pad 18 is formed on a side of the wiring layer remote from the light emitting element 15, and is electrically connected to the light emitting element 15 through the wiring layer. Specifically, the conductive pad 18 includes a portion formed over the first wiring layer 14 within the first opening 130, and a portion formed over the second portion 162 of the second wiring layer 16. The conductive pad 18 in this embodiment is formed as a thick pad having a thickness (i.e., a thickness in the height direction along the longitudinal direction of the sectional view shown in fig. 1) of more than 20 μm. Alternatively, the conductive pad 18 is formed in a multi-layer structure, as shown in fig. 1, may include a conductive layer 1801 and a protective layer 1802, wherein the conductive layer 1801 may be a single layer or a multi-layer made of at least one material of titanium, copper, gold, platinum, etc., and the thickness of the conductive layer 1801 is 10 to 50 μm, further, 20 μm or more, for example, 20 μm, 30 μm, 40 μm; the thickness of the protective layer 1802 is between 25nm and 50nm. The protective layer 1802 completely covers the surface of the conductive layer 1801, and can effectively prevent the conductive layer 1801 from being oxidized, thereby improving the stability of the light emitting module 10. When the light emitting module 10 is mounted on the display device, the protective layer 1802 is damaged or removed. The protective layer 1802 does not affect the bondability and conductivity of the conductive pads 18. The protective layer 1802 may be made of metal materials such as gold and platinum, and the conductive pad 18 is soldered to the circuit board by using a soldering material at a predetermined temperature during the process of mounting the light emitting module 10 on the display device, and the soldering material flows and deforms during the soldering process, so that the deformation of the soldering material may damage the integrity of the protective layer 1802 made of metal materials such as gold and platinum, thereby removing the protective layer 1802 and soldering the conductive layer 1801. Alternatively, the protective layer 1802 may be an organic material such as OSP, which is dissolved and removed by soldering the conductive pads 18 with the circuit board using a soldering material at a predetermined temperature during the mounting of the light emitting module 10 to the display device.

In an alternative embodiment, an adhesive layer is also provided between the conductive layer 1801 and the protective layer 1802, as shown. The adhesive layer may be a single layer or a plurality of layers made of at least one material of chromium, titanium, nickel, tantalum nitride, tantalum, and the like. The thickness of the adhesive layer is preferably 3 to 5 μm, and the adhesive layer is provided so as to increase adhesion to the conductive layer 1801 and prevent accidental damage occurring when the protective layer 1802 is removed.

In an alternative embodiment, the protective layer 1802 in the conductive pad 18 is replaced by the eutectic layer 1804, and the eutectic layer 1804 may be a single layer or multiple layers made of at least one material of Sn, snAg, auSn, and the thickness thereof is between 10nm and 50nm. The eutectic layer 1804 can effectively increase the binding force of the light emitting module 10 when applied to a circuit board, and the convenience of use of a client is improved without printing solder paste again or brushing a small amount of solder paste.

Referring again to fig. 2 and 3, the conductive pad 18 includes a first pad 181, a second pad 182, a third pad 183, and a fourth pad 184, the first pad 181 serving as a common pad electrically connects the first electrodes 1501 of the first, second, and third light emitting elements 151, 152, and 153 through the first sub-wiring 141, and the second, third, and fourth pads 182, 183, and 184 are respectively connected to the second electrodes 1502 of the respective light emitting elements 15 through the corresponding sub-wirings. Alternatively, the first pad 181 serves as a common pad, the second electrodes 1502 of the first, second, and third light emitting elements 151, 152, and 153 are electrically connected by the first sub-wiring 141, and the second, third, and fourth pads 182, 183, and 184 are respectively connected to the first electrodes 1501 of the light emitting elements 15 by the corresponding sub-wirings.

Referring to fig. 1, the light emitting module 10 of the present embodiment further includes an encapsulation layer 17, where the encapsulation layer 17 is filled around the conductive pads 18 and covers the exposed first protection layer 13, so as to electrically isolate adjacent sub-pads. The encapsulation layer 17 may be a glue layer that absorbs light, and may be, for example, a transparent or translucent material layer such as silica gel, epoxy, polyimide, low temperature glass, polysiloxane, polysilazane, etc. dispersed with a black filling component including, but not limited to, carbon black, titanium nitride, iron oxide, ferroferric oxide, iron powder, etc. The encapsulation layer 17 has a thickness to protect the light emitting element 15 and the wiring layer from external factors, and the thickness of the encapsulation layer 17 is generally greater than 20 μm.

In an alternative embodiment, referring to fig. 1, the light emitting module 10 further comprises a transparent layer 11, and the light emitting element 15 is disposed above the transparent layer 11. In this embodiment, the surface of the transparent layer 11 away from the light emitting element 15 is the light emitting surface of the light emitting module 10, that is, the light emitted from the light emitting element 15 is emitted to the outside through the transparent layer 11. The transparent layer 11 has a light transmittance of 60% or more in the visible light range. The transparent layer 11 includes a first transparent layer 111 and a second transparent layer 112, and the second transparent layer 112 is located between the first transparent layer 111 and the light emitting element 15. The first transparent layer 111 may be selected from inorganic light-transmitting materials such as glass, transparent ceramics, sapphire, and the like. The light emitting module 10 needs to have a certain thickness in order to be used by clients, so the thickness of the first transparent layer 111 is greater than 10 μm, and may be, for example, 30 μm to 50 μm, 50 μm to 100 μm, or 100 μm to 300 μm.

The second transparent layer 112 is positioned between the first transparent layer 111 and the light emitting element 15 so that the light emitting element 15 can be adhered to the first transparent layer 111 through the second transparent layer 112. The second transparent layer 112 may entirely cover the entire surface of the first transparent layer 111, but is not limited thereto, and may be positioned only under the light emitting element 15 so that the light emitting element 15 can be adhered to the first transparent layer 111 through the second transparent layer 112. Since the different light emitting elements 15 generally have different thicknesses, by disposing the second transparent layer 112 between the first transparent layer 111 and the light emitting elements 15, the height difference of each light emitting element 15 can be reduced, so that the light emitted from the side surface of the light emitting element 15 is absorbed by the filling layer 12 as much as possible, to improve the contrast ratio of the light emitting module 10. The thickness of the second transparent layer 112 is 1 μm to 15 μm or 3 μm to 10 μm.

Example two

The embodiment provides a manufacturing method of the light emitting module 10. As shown in fig. 7, the manufacturing method includes the steps of:

s100: providing a transparent layer;

s200: a plurality of light emitting elements are fixed above the transparent layer at intervals;

as shown in fig. 8, first, a first transparent layer 111 is provided, and the first transparent layer 111 is specifically provided with reference to embodiment one. The first transparent layer 111 includes a first surface and a second surface, where the first surface is a light emitting surface. A second transparent layer 112 is provided over the second surface, the second transparent layer 112 fixing the light emitting element 15 to the first transparent layer 111. In this embodiment, the first transparent layer 111 is a sapphire substrate. The arrangement of the light emitting element 15 and the second transparent layer 112 can be set as described with reference to the first embodiment.

S300: forming a filling layer 12 around the light emitting element;

as described in the first embodiment, the black gel layer capable of absorbing light is selected, for example, a black filling component is filled in a silica gel with good fluidity to form the filling layer 12. As shown in fig. 8, the filling layer 12 is filled between the light emitting elements 15, and in order to ensure that color mixing or interference does not occur between adjacent light emitting elements 15, the filling layer 12 covers at least the active layer of the light emitting element 15, and further covers all the side walls of the light emitting element 15. As an alternative embodiment, the thickness of the filling layer 12 may be greater than that of the light emitting element 15, and light interference caused by light leakage at the bottom of the light emitting element 15 may be prevented. The thickness of the filler layer 12 is preferably less than 15 μm.

S400: fabricating a first wiring layer 14 over the filling layer 12 and the light emitting element;

as shown in fig. 10, a first wiring layer 14 is formed over the light emitting element 15 and the filler layer 12, and the first wiring layer 14 simultaneously serves as a seed layer for subsequently forming the conductive pad 18. As shown in fig. 11, the first wiring layer 14 includes the first sub-wiring 141, the second sub-wiring 142, the third sub-wiring 143, and the fourth sub-wiring 144 described in the first embodiment, and further includes the conductive pad forming region 140 and the connection portion 145. The portion within the dashed box as shown in fig. 11 corresponds to the first wiring layer 14 of one conductive module shown in fig. 3 and 4. The conductive pad forming region 140 is used for subsequent growth of the conductive pads 18, and the connection portion 145 connects the first wiring layers 14 of each conductive module in series so as to achieve subsequent growth of the conductive pads 18. The arrangement of specific sub-wiring layers in the first wiring layer 14 can be described with reference to the first embodiment.

S500: forming a first protective layer over the first wiring layer 14, the first protective layer being formed with a first opening;

as shown in fig. 12, the first protective layer 13 is formed over the first wiring layer 14, and the thickness of the first protective layer 13 is not preferably excessively large, so that the second wiring layer 16 formed later thereon can be ensured to have good structural characteristics, and the subsequent removal of part of the second wiring layer 16 is facilitated. For this reason, in the present embodiment, the thickness of the first protective layer 13 is 1 μm to 7 μm. As shown in fig. 12 and 13, the first protective layer 13 is formed with a first opening 130, and the first opening 130 is formed in the conductive pad forming region 140 in the first wiring layer 14. And to ensure that the subsequently formed conductive pad 18 is fully located in the conductive pad forming region 140, the shape of the first opening 130 corresponds to the shape of the conductive pad forming region 140, and the opening size (e.g., width) of the first opening 130 is slightly smaller than the width of the conductive pad forming region 140.

S600: forming a second wiring layer over the first protection layer, the second wiring layer covering the first wiring layer and being formed at an edge region of the first wiring layer exposed by the first opening;

Before forming the second wiring layer 16, first, as shown in fig. 14 and 15, a second protective layer 20 is formed in the first opening 130 shown in fig. 13, the second protective layer 20 being also an insulating material layer, which may be the same or a different insulating material layer as the first protective layer 13, and the second protective layer 20 being formed as a material layer that is easy to remove, for example, a photoresist material. The thickness of the second protection layer 20 may be the same as or different from that of the first protection layer 13, and in this embodiment, the thickness of the second protection layer 20 is the same as that of the first protection layer 13, and is also 3 μm to 4 μm, so as to facilitate subsequent removal. The second protective layer 20 is formed in the first opening 130 with a gap having a width d4 of 2 μm or more and 1/3 or less of the width of the conductive pad 18 to be formed later with the first protective layer 13 forming the first opening 130. This ensures that the subsequently formed second wiring layer 16 can be smoothly formed into the gap to be connected to the first wiring layer 14, while ensuring that the second wiring layer 16 in the gap is not damaged when the second protective layer 20 is subsequently removed.

As shown in fig. 16, the second wiring layer 16 is formed over the structure shown in fig. 15, at which time the second wiring layer 16 covers the first protective layer 13 and the second protective layer 20 while forming a gap therebetween. Thereafter, as shown in fig. 17, the second protective layer 20 and the metal layer thereon are removed. The second protective layer 20 may be removed, for example, by solution etching, and the second wiring layer 16 formed thereon may be removed at the same time. At this time, as shown in fig. 18, the second wiring layer 16 is formed over the first protective layer 13 while being formed in the first opening 130, and the first wiring layer 14 covering the edge area of the bottom of the first opening 130 is connected to the first wiring layer 14. Since the second wiring layer 16 is formed over the first protection layer 13, the first protection layer 13 has good surface characteristics, and thus the second wiring layer 16 is formed as a uniform continuous and surface-flattened metal layer, whereby the second wiring layer 16 has uniform good conductivity.

S700: forming a conductive pad filling the first opening and formed over a periphery of the first opening, the conductive pad being electrically connected with the first conductive layer;

as shown in fig. 19 and 20, after the structure shown in fig. 18 is formed, a mask layer 19 is formed over the second wiring layer 16, the mask layer 19 covers the second wiring layer 16 except for the first opening 130, and a second opening 190 is formed in a region corresponding to the first opening 130. Optionally, the width of the second opening 190 is greater than the width of the first opening 130, thereby ensuring that the first conductive layer 1801 is fully exposed to ensure a smooth completion of the electroplating process to form the conductive pad 18 of a desired thickness.

Thereafter, an electroplating process is performed to form the conductive pad 18, electricity is applied to the structure shown in fig. 19 through the second wiring layer 16, current is transferred to the first wiring layer 14 at the first opening 130 through the second wiring layer 16, electroplating is started, and the conductive pad 18 is formed at the positions of the first opening 130 and the second opening 190. As described above, since the second wiring layer 16 is formed over the first protection layer 13 with good continuity and surface flatness, the uniformity of the current transmitted therethrough is good, and the conductive pads 18 can be uniformly formed in the first openings, so that the conductive pads 18 have good structural flatness. Ensuring good electrical performance.

The conductive pad 18 may be formed in a multi-layered structure as shown in fig. 1 or 5 or 6, and may be described with reference to the first embodiment.

S800: and removing the second wiring layer except for the part covered by the conductive pad.

After the conductive pad 18 is formed by the electroplating process, as shown in fig. 21, the mask layer 19 and the second wiring layer 16 covered by the mask layer 19 are removed. And further comprises the step of forming an encapsulation layer 17 over the structure shown in fig. 21. The encapsulation layer 17 can be provided as described with reference to the first embodiment.

Example III

The present embodiment provides a display device, as shown in fig. 22, the display device 30 includes a circuit substrate 301, and a plurality of light emitting units 301 fixed to the circuit substrate 301, wherein the light emitting units 301 include the light emitting module 10 provided in the first embodiment.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims

1. A light emitting module, comprising:

a plurality of light emitting elements arranged at intervals;

a filling layer filled between adjacent light emitting elements;

2. The light emitting module of claim 1, wherein the conductive pad comprises a portion in contact with the second wiring layer and a portion in contact with the first wiring layer.

3. The lighting module of claim 1, further comprising: and a first protection layer over the first wiring layer, the first protection layer forming a first opening in a region where the conductive pad is located, the second wiring layer including a first portion formed at a bottom of the first opening, and a second portion formed over the first protection layer at a periphery of the first opening, the conductive pad filling the first opening and being formed over the second wiring layer.

4. A light emitting module as recited in claim 3, wherein the first protective layer has a thickness of between 1 μm and 7 μm.

5. A light emitting module as recited in claim 3, wherein a width of the first wiring layer covered by the first protective layer is less than 20 μm at an edge of the first wiring layer.

6. A light emitting module according to claim 3, wherein a width of the first portion in a longitudinal section direction of the conductive pad is 2 μm or more and 1/3 or less of a width of the conductive pad.

7. A light emitting module according to claim 3, wherein a width of the second portion in a longitudinal section direction of the conductive pad is 2 μm or more and 1/3 or less of a width of the conductive pad.

8. The light emitting module of claim 1, wherein the filler layer covers at least an active layer of the light emitting element.

9. The light-emitting module according to claim 1, wherein a thickness of the light-emitting element is 15 μm or less, and a pitch between adjacent light-emitting elements is less than 50 μm.

10. The light emitting module of claim 3 further comprising an encapsulation layer over the first protective layer and formed around the perimeter of the conductive pad, the encapsulation layer having a thickness greater than 20 μm.

11. A light emitting module as recited in claim 3, wherein the encapsulation layer is a transparent insulating layer or a black insulating layer.

12. The light emitting module of claim 1 further comprising a transparent layer over the transparent layer, the transparent layer comprising a first transparent layer and a second transparent layer, the second transparent layer interposed between the first transparent layer and the light emitting element, the first transparent layer having a thickness greater than 10 μm and the second transparent layer having a thickness less than 10 μm.

13. The light emitting module of claim 1, wherein the plurality of light emitting elements comprises a red light chip, a green light chip, and a blue light chip.

14. The light emitting module of claim 1, wherein the first wiring layer has a thickness of 50nm to 1000nm.

15. The light emitting module of claim 1, wherein the second wiring layer has a thickness of 50nm to 1000nm.

16. The light emitting module of claim 1, wherein the first wiring layer is a metal layer formed of Ti and Cu.

17. The light emitting module of claim 1, wherein the second wiring layer is a metal layer formed of Ti and/or Cu.

18. The light-emitting module according to claim 1, wherein the conductive pad comprises a conductive layer, an adhesive layer, and a protective layer, wherein the thickness of the conductive layer is 20 μm or more, the thickness of the adhesive layer is 3 μm to 5 μm, and the thickness of the protective layer is 25nm to 50nm.

19. The light emitting module of claim 1, wherein the conductive pad comprises a conductive layer, an adhesive layer, and a eutectic layer, the conductive layer has a thickness of 20 μm or more, the adhesive layer has a thickness of 3 μm to 5 μm, and the eutectic layer has a thickness of 10nm to 50nm.

20. The light emitting module of claim 1, wherein the conductive pad comprises a conductive layer, an adhesive layer, a eutectic layer, and a protective layer, the conductive layer has a thickness of 20 μm or more, the adhesive layer has a thickness of 3 μm to 5 μm, the eutectic layer has a thickness of 10nm to 50nm, and the protective layer has a thickness of 25nm to 50nm.

21. The light emitting module of any one of claims 18-20 further comprising an encapsulation layer filled around the perimeter of the conductive pads, wherein a surface of the encapsulation layer distal from the routing layer is flush with a surface of the conductive layer distal from the routing layer.

22. The lighting module of claim 1, wherein the conductive pad has a thickness greater than 5 μm.

23. A display device comprising a circuit substrate and a plurality of light emitting units fixed to the circuit substrate, the light emitting units comprising the light emitting module of any one of claims 1 to 22.