A packaging structure and manufacturing method for a miniature light-emitting diode chip

Abstract

This invention relates to the field of micro LED chip packaging technology, and proposes a packaging structure for a micro LED chip, comprising: a substrate; a circuit board disposed on the top surface of the substrate; a micro LED chip disposed on the top surface of the substrate, wherein a first surface of the micro LED chip is connected to the substrate, and an active region is provided on a second surface of the micro LED chip opposite to the first surface; the circuit board is electrically connected to the micro LED chip; a molding compound disposed around the micro LED chip and exposing the active region of the micro LED chip; and a light-transmitting cover disposed on the active region of the micro LED chip. This invention, by providing a light-transmitting cover on the micro LED chip, can protect the active region and improve the overall packaging strength.

Description

Technical Field

[0001] This invention generally relates to the field of micro light-emitting diode (LED) chip packaging technology. Specifically, this invention relates to a packaging structure for a micro LED chip and a method for manufacturing the same. Background Technology

[0002] Microlight Emitting Diode (LED) technology is a high-pixel-density LED planar display technology that uses micrometer-scale LEDs as pixels and assembles them on a control backplane at micrometer-scale intervals. Compared to traditional LEDs, microlight Emitting Diodes have advantages such as high brightness, high contrast, high response speed, high efficiency, long lifespan, wide color gamut, and small size, and have been widely used.

[0003] The package structure of a miniature LED chip serves as a bridge connecting the miniature LED chip and external circuitry, and is crucial to the performance of the miniature LED. However, existing miniature LED chip package structures typically lack protection for the light-emitting area, and the overall strength of the package needs further improvement. Summary of the Invention

[0004] To at least partially solve the aforementioned problems in the prior art, the present invention proposes a packaging structure for a micro light-emitting diode (LED) chip, characterized in that it comprises: a substrate; a circuit board disposed on the top surface of the substrate; a micro LED chip disposed on the top surface of the substrate, wherein a first surface of the micro LED chip is connected to the substrate, and an active region is provided on a second surface of the micro LED chip opposite to the first surface, the circuit board being electrically connected to the micro LED chip; a molding compound disposed around the micro LED chip and exposing the active region of the micro LED chip; and a light-transmitting cover plate disposed over the active region of the micro LED chip.

[0005] In one embodiment of the present invention, a portion of the back side of the circuit board is fixed to the substrate by circuit board adhesive, and another portion extends beyond the substrate.

[0006] In one embodiment of the invention, the circuit board has an extension line interface at an end extending beyond the substrate.

[0007] In one embodiment of the present invention, all sides of the substrate extend beyond the coverage area of ​​the micro light-emitting diode chip; or

[0008] At least a portion of the sides of the substrate does not extend beyond the coverage area of ​​the micro LED chip.

[0009] In one embodiment of the present invention, the substrate includes a copper substrate, an Invar steel substrate, or a ceramic substrate.

[0010] In one embodiment of the present invention, the circuit board includes a flexible circuit board or a printed circuit board.

[0011] In one embodiment of the present invention, the material of the encapsulant includes epoxy resin, silicone, or ethylene-vinyl acetate copolymer.

[0012] In one embodiment of the present invention, the micro light-emitting diode chip is electrically connected to the circuit board via leads, and the plastic encapsulation covers the leads.

[0013] In one embodiment of the present invention, the edge region of the second side of the micro light-emitting diode chip is provided with a first connection portion, and the surface of the circuit board away from the substrate is provided with a second connection portion, wherein the lead connects the first connection portion and the second connection portion.

[0014] In one embodiment of the invention, the material of the lead wire includes gold or aluminum.

[0015] In one embodiment of the present invention, the first side of the micro light-emitting diode chip is fixed on the substrate by a chip adhesive, wherein the material of the chip adhesive includes conductive adhesive, silver paste or die bonding film.

[0016] In one embodiment of the present invention, the micro light-emitting diode chip includes an integrated circuit backplane and an active region disposed on the integrated circuit backplane. The active region includes a pixel array formed by micro light-emitting diodes, the pixel array including a plurality of micro light-emitting diode pixels, each pixel including one or more micro light-emitting diodes.

[0017] In one embodiment of the present invention, the micro light-emitting diode includes a micron-scale light-emitting mesa structure. The micron-scale light-emitting mesa structure includes a first type epitaxial layer, a second type epitaxial layer, and a light-emitting layer between the first type epitaxial layer and the second type epitaxial layer. The first type epitaxial layer is a semiconductor material having a first conductivity type and includes multiple semiconductor layers. The second type epitaxial layer is a semiconductor material having a second conductivity type and includes multiple semiconductor layers.

[0018] In one embodiment of the present invention, there is a gap between the bottom surface of the light-transmitting cover and the surface of the active region.

[0019] In one embodiment of the present invention, the material of the light-transmitting cover includes: glass, silicon dioxide, or magnesium fluoride.

[0020] In one embodiment of the present invention, the top surface height of the encapsulation body is higher than the top surface height of the active region, the light-transmitting cover plate has a middle region corresponding to the active region and a support region located around the middle region, the support region covers and is fixed to the surface of the encapsulation body, and there is a gap between the bottom surface of the middle region and the surface of the active region.

[0021] In one embodiment of the present invention, the portion of the molding compound adjacent to the active region of the micro LED chip forms a downward molding step, the top surface of the molding step being lower than the top surface of the molding compound, the light-transmitting cover having an intermediate region corresponding to the active region and a support region located around the intermediate region, the support region covering and fixing to the surface of the molding step, and a gap between the bottom surface of the intermediate region and the surface of the active region.

[0022] In one embodiment of the present invention, the top surface height of the plastic-sealed step is higher than the surface height of the active region.

[0023] In one embodiment of the present invention, the position where the light-transmitting cover plate overlaps with the top surface of the plastic-sealed step is provided with a light-transmitting cover plate adhesive. The light-transmitting cover plate is fixed by the light-transmitting cover plate adhesive, so that it is positioned above the active area.

[0024] In one embodiment of the present invention, the light-transmitting cover plate has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surrounding surface of the active region, and there is a gap between the bottom surface of the central region and the surface of the active region.

[0025] In one embodiment of the present invention, the height of the top surface of the light-transmitting cover is flush with the top surface of the encapsulated body.

[0026] In one embodiment of the present invention, the light-transmitting cover has an intermediate region corresponding to the active region and a support region located around the intermediate region. The support region covers and is fixed to the surface of the encapsulated body. There is a gap between the bottom surface of the intermediate region and the surface of the active region. The top surface of the light-transmitting cover is flat, and the bottom surface of the intermediate region protrudes downward relative to the bottom surface of the support region to form a boss. The boss extends downward into the encapsulated window above the active region that is not covered by the encapsulated body.

[0027] In one embodiment of the present invention, the position where the light-transmitting cover plate overlaps with the top surface of the plastic sealant is provided with a light-transmitting cover plate adhesive, and the light-transmitting cover plate is fixed by the light-transmitting cover plate adhesive, so that it is positioned above the active area.

[0028] In one embodiment of the present invention, the material of the light-transmitting cover adhesive is ethylene-vinyl acetate copolymer.

[0029] An embodiment of the present invention provides a method for manufacturing a package structure of a micro light-emitting diode chip, comprising: fixing a circuit board to one end of the top surface of a substrate; fixing a micro light-emitting diode chip to the top surface of the substrate; forming leads between the circuit board and the micro light-emitting diode chip by wire bonding; forming a molding compound that covers the micro light-emitting diode chip; and covering the active area of ​​the micro light-emitting diode chip with a light-transmitting cover plate.

[0030] In one embodiment of the present invention, the top surface height of the encapsulation body is higher than the top surface height of the active region, the light-transmitting cover plate has a middle region corresponding to the active region and a support region located around the middle region, the support region is covered and fixed to the surface of the encapsulation body by the light-transmitting cover plate adhesive, and there is a gap between the bottom surface of the middle region and the surface of the active region.

[0031] In one embodiment of the present invention, a downward molding step is formed in the portion of the molding compound adjacent to the active region of the micro LED chip. The top surface of the molding step is lower than the top surface of the molding compound. The light-transmitting cover has an intermediate region corresponding to the active region and a support region located around the intermediate region. The support region is covered and fixed to the surface of the molding step by a light-transmitting cover adhesive. There is a gap between the bottom surface of the intermediate region and the surface of the active region.

[0032] In one embodiment of the present invention, the light-transmitting cover plate has a middle region corresponding to the active region and a support region located around the middle region. The support region is covered and fixed to the surrounding surface of the active region by a light-transmitting cover plate adhesive. There is a gap between the bottom surface of the middle region and the surface of the active region.

[0033] In one embodiment of the present invention, the light-transmitting cover has a middle region corresponding to the active region and a support region located around the middle region. The support region is covered and fixed to the surface of the encapsulated body by a light-transmitting cover adhesive. There is a gap between the bottom surface of the middle region and the surface of the active region. The top surface of the light-transmitting cover is flat, and the middle region of the bottom surface protrudes downward relative to the support region to form a boss. The boss extends downward into the encapsulated window above the active region that is not covered by the encapsulated body.

[0034] Embodiments of the present invention provide a packaging structure for a miniature light-emitting diode (LED) chip and a method for manufacturing the same. Compared with existing miniature LED chip packaging structures, embodiments of the present invention provide a light-transmitting cover plate above the active region of the miniature LED chip, increasing protection for the active region and improving the overall strength of the package. Furthermore, in embodiments of the present invention, the light-transmitting cover plate can be disposed on the molding step, which reduces the overall thickness of the package while ensuring its overall strength. Attached Figure Description

[0035] To further illustrate the advantages and other features of the various embodiments of the present invention, a more specific description of the embodiments of the present invention will be presented with reference to the accompanying drawings. It is understood that these drawings depict only typical embodiments of the invention and are therefore not intended to limit its scope. In the drawings, identical or corresponding parts will be indicated by the same or similar reference numerals for clarity.

[0036] Figure 1 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown.

[0037] Figure 2 A cross-sectional schematic diagram illustrating the manufacturing process of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown.

[0038] Figure 3 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown.

[0039] Figure 4 A cross-sectional schematic diagram illustrating the manufacturing process of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown.

[0040] Figure 5 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown.

[0041] Figure 6 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown. Detailed Implementation

[0042] It should be noted that the components in the various figures may be shown exaggeratedly for illustrative purposes and are not necessarily to scale. In each figure, the same reference numerals are used for components that are identical or have the same function.

[0043] In this invention, unless otherwise specified, "arranged on," "arranged above," and "arranged on" do not exclude the possibility of an intermediate element between them. Furthermore, "arranged on or above" merely indicates the relative positional relationship between two components, and in certain cases, such as when the product orientation is reversed, it can also be converted to "arranged below or under," and vice versa.

[0044] In this invention, the various embodiments are merely intended to illustrate the solutions of the invention and should not be construed as limiting.

[0045] In this invention, unless otherwise specified, the quantifiers “a” and “one” do not exclude scenarios involving multiple elements.

[0046] It should also be noted that, in the embodiments of the present invention, only a portion of the components or parts may be shown for clarity and simplicity. However, those skilled in the art will understand that, under the teachings of the present invention, necessary components or parts can be added as needed for specific scenarios. Furthermore, unless otherwise stated, features in different embodiments of the present invention can be combined with each other. For example, a feature in the second embodiment can replace a corresponding or functionally identical or similar feature in the first embodiment, and the resulting embodiment will also fall within the scope of disclosure or description of this application.

[0047] It should also be noted that, within the scope of this invention, the terms "same," "equal," and "equal to" do not imply that the two values ​​are absolutely equal, but rather allow for a certain reasonable margin of error. In other words, the terms also encompass "substantially the same," "substantially equal," and "substantially equal to." Similarly, in this invention, the directional terms "perpendicular to," "parallel to," etc., also encompass the meanings of "substantially perpendicular to" and "substantially parallel to."

[0048] Furthermore, the numbering of the steps in the methods of the present invention does not limit the execution order of the method steps. Unless otherwise specified, the method steps may be executed in different orders.

[0049] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0050] Figure 1 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown. Figure 1 As shown, the micro LED chip packaging structure includes a substrate 101, a circuit board 102, a micro LED chip 103, leads 105, a molding compound 106, and a light-transmitting cover 107.

[0051] In some embodiments, the thickness of the substrate 101 is greater than or equal to 100 mm. The substrate 101 may be a reinforcing plate used to improve the strength and rigidity of the packaging structure, as well as to enhance the durability and reliability of the packaging structure. In some embodiments, the substrate 101 may be a metal substrate such as a copper substrate, an Invar steel substrate, or a stainless steel substrate, or the substrate 101 may be a ceramic substrate. These materials all possess properties such as corrosion resistance, wear resistance, and high temperature resistance.

[0052] In some embodiments, the circuit board 102 is disposed on the substrate 101. In some embodiments, a portion of the back side of the circuit board 102 is fixed to the substrate 101 by adhesive 109, and another portion extends beyond the substrate 101. In some embodiments, the circuit board 102 has an extension cable interface at its end extending beyond the substrate 101. In some embodiments, the thickness of the circuit board 102 is greater than or equal to 100 mm. The circuit board 102 can be connected to the driving circuit of the micro-LED chip 103 via leads 105 to connect it to an external power supply or control source. The circuit board 102 may have built-in conductive lines configured to connect the interface area of ​​the micro-LED chip 103 to an external interface. The circuit board 102 may also have an external interface (not shown) configured to connect an external power supply and / or control signals to power and / or control the micro-LED chip 103. The external interface may be a pin-type interface or a gold finger-type interface; other types of interfaces are also conceivable. The circuit board 102 is preferably a flexible circuit board (FPC) or a printed circuit board (PCB), and the conductive lines are traces arranged on the flexible printed circuit board.

[0053] In some embodiments, the micro LED chip 103 is disposed on the substrate 101, wherein a first surface of the micro LED chip 103 is connected to the substrate 101, and an active region 1031 is provided on a second surface of the micro LED chip 103 opposite to the first surface. In some embodiments, the shape of the micro LED chip 103 is square, circular, or other optional shapes. Figure 1 As shown, the first surface of the substrate 101 is completely supported by the substrate 101, and all sides of the substrate 101 extend beyond the coverage area of ​​the micro-LED chip 103. However, in other embodiments of the invention, the substrate 101 may be appropriately reduced in size, and at least a portion of the sides of the substrate 101 may not extend beyond the coverage area of ​​the micro-LED chip 103. The substrate 101 may support only a portion of the first surface of the substrate 101.

[0054] The micro-LED chip 103 has a size not exceeding 1 cm, preferably not exceeding 20 micrometers. The micro-LED structures are formed in an array within the micro-LED chip 103, with resolutions such as 720*480, 640*480, 1920*1080, 1280*720, 2K, or 4K. The diameter of the micro-LED structure is in the nanometer range, for example, from 20 nm to 100 nm.

[0055] The micro-LED chip 103 includes an integrated circuit (IC) backplane and an active region 1031 disposed on the IC backplane. The active region 1031 includes a pixel array formed by micro-LEDs, the pixel array comprising a plurality of micro-LED pixels. Each pixel may include one or more micro-LEDs. That is, each micro-LED may form at least a portion of the pixel elements on the micro-LED chip 103. For example, each pixel may include a micro-LED of one color, thereby the active region of the micro-LED chip 103 is a monochrome pixel array. Alternatively, each pixel may include micro-LEDs of two or more colors, thereby the active region of the micro-LED chip 103 is a color pixel array.

[0056] In some embodiments, the IC backplane may be electrically connected to each microLED in the microLED array via individual metal interconnects. In some embodiments, each microLED may be electrically controlled individually by the IC backplane. In some embodiments, the IC backplane may be electrically connected to the electrodes of the microLED chip 103 via metal interconnects. In some embodiments, a dielectric layer may be formed in the gaps between the microLEDs. In some embodiments, a dielectric layer may also be formed in the gaps between interconnects.

[0057] In some embodiments, each micro-LED in the micro-LED array may include a micrometer-scale light-emitting mesa structure. In some embodiments, the micrometer-scale light-emitting mesa structure may, from bottom to top, include a first type epitaxial layer, a light-emitting layer, and a second type epitaxial layer. That is, in the three-layer structure, the first type epitaxial layer is closest to the IC backplane; the light-emitting layer is located above the first type epitaxial layer and further away from the IC backplane; and the second type epitaxial layer is located above the light-emitting layer and furthest away from the IC backplane. In some embodiments, the light-emitting layer is formed of multiple stacked quantum well layers, particularly superlattice stacked quantum well layers. Preferably, the superlattice stacked quantum well layers include multiple pairs of quantum well layers stacked with quantum barrier layers. In some embodiments, the first type epitaxial layer is a semiconductor material having a first conductivity type and includes multiple semiconductor layers. The main substrate material of the first type epitaxial layer may be, but is not limited to, materials such as Ga, N, As, P, In, or Al. Furthermore, the first type epitaxial layer may, from top to bottom, include, but is not limited to, a waveguide layer, a confinement layer, a transition layer, and a window layer; additionally, an ohmic contact layer may be formed below the window layer. In some embodiments, the second type of epitaxial layer is a semiconductor material having a second conductivity type and includes multiple semiconductor layers. The main substrate material of the second type of epitaxial layer may be, but is not limited to, materials such as Ga, N, As, P, In, or Al. Furthermore, the first type of epitaxial layer may include, from top to bottom, a confinement layer and a waveguide layer; additionally, in some embodiments, an ohmic contact layer may be formed on the confinement layer. In some embodiments, the micron-scale light-emitting mesa structure can emit red, blue, green, or other arbitrary colors of light.

[0058] In some embodiments, a top conductive layer may be formed on the top surface of the micro-LED array. In some embodiments, the top conductive layer may be shared by all micro-LEDs in the micro-LED array. In some embodiments, the light-emitting layer may include at least one quantum well layer. In some embodiments, the micro-LED array may include a single-layer micro-LED structure. In some embodiments, the micro-LED array may include a multi-layer vertically stacked micro-LED structure.

[0059] In some embodiments, the micro-LED array may include micro-LEDs of one or more colors. In some embodiments, the spacing of the micro-LED array, i.e., the minimum center-to-center distance between the micro-LEDs, may be between about 2 micrometers and about 50 micrometers. In some embodiments, the number of pixels on the micro-LED chip 103 may be between thousands and millions.

[0060] In some embodiments, a microlens is disposed above a micro-LED array, and the lateral dimension of the bottom of the microlens is greater than the lateral dimension of the light-emitting area of ​​the micro-LED; or, the lateral dimension of the bottom of the microlens may be less than or equal to the lateral dimension of the light-emitting area of ​​the micro-LED.

[0061] In some embodiments, a microlens may cover one or more lensless micro-light-emitting diodes. Multiple microlenses constitute a microlens array. The microlenses in a microlens array are typically identical. Examples of microlenses include spherical microlenses, aspherical microlenses, Fresnel microlenses, and cylindrical microlenses. The individual microlenses in the microlens array of the micro-light-emitting diode chip 103 may be identical or different in shape, curvature, optical power, size, base, and spacing.

[0062] In some embodiments, the microlens may be made of various materials that are transparent to light of various wavelengths emitted by the micro-light-emitting diode. Exemplary transparent materials for the microlens include polymers and dielectric materials. In some embodiments, the dielectric material includes one or more materials such as silicon oxide, silicon nitride, silicon carbide, titanium oxide, zirconium oxide, aluminum oxide, etc. In some embodiments, the microlens is made of photoresist. In some embodiments, the microlens is deposited directly on the surface of the micro-light-emitting diode using chemical vapor deposition (CVD) technology.

[0063] In some embodiments, a chip adhesive 104 is provided between the substrate 101 and the micro LED chip 103, wherein the substrate 101 and the micro LED chip 103 are bonded together by the chip adhesive 104. In some embodiments, the chip adhesive 104 may be a conductive adhesive or a die bond film (DAF). The conductive adhesive may be silver paste or other metal pastes with low conductivity (e.g., gold, copper, nickel, etc.). The chip adhesive has excellent bonding and thermal conductivity properties, can remain stable in high-temperature environments, and provides reliable mechanical connection and thermal management for the chip.

[0064] In some embodiments, the lead 105 electrically connects the circuit board 102 to the micro-LED chip 103. In some embodiments, the edge region of the second side of the micro-LED chip has a first connection portion (metal pad), and the surface of the circuit board 102 away from the substrate has a second connection portion, wherein the lead connects the first connection portion and the second connection portion. Here, the term "edge region" refers to a region with a physical boundary distance of 20 micrometers to 400 micrometers from the micro-LED chip. In some embodiments, the lead 105 is a gold wire, an aluminum wire, or other conductive metal material.

[0065] In some embodiments, the encapsulation body 106 is disposed around the micro-LED chip 103 and exposes the active region 1031 of the micro-LED chip 103. In other words, the encapsulation body 106 covers all sides of the micro-LED chip 103 and a portion of its top surface (excluding the active region 1031), the top and side surfaces of the circuit board 102 adjacent to the micro-LED chip 103, and a portion of the top surface of the substrate 101. A molding opening is formed above the active region of the micro-LED chip 103 not covered by the encapsulation body 106. The encapsulation body 106 covers the lead wire 105 to provide insulation protection for the lead wire 105. The active region 1031 of the micro-LED chip 103 is not covered by the encapsulation body 106. In some embodiments, the material of the encapsulation body 106 includes epoxy resin, silicone, and ethylene-vinyl acetate copolymer (EVA).

[0066] In some embodiments, the light-transmitting cover 107 is disposed over the active region of the micro-LED chip 103, wherein the light-transmitting cover 107 is used to protect the active region 1031 on the micro-LED chip 103. In some embodiments, a gap is left between the bottom surface of the light-transmitting cover 107 and the surface of the active region 1031 to prevent the light-transmitting cover 107 from contacting the surface of the active region 1031. In some embodiments, the material of the light-transmitting cover 107 may be glass or other light-transmitting materials such as silicon dioxide or magnesium fluoride.

[0067] In some embodiments, the top surface height of the encapsulation body 106 is higher than the top surface height of the active region 1031. The light-transmitting cover 106 has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surface of the encapsulation body 106, and there is a gap between the bottom surface of the central region and the surface of the active region 1031. That is, when the light-transmitting cover 107 is placed, the periphery of the light-transmitting cover 107 is supported on the top surface of the encapsulation body 106, while the portion opposite to the active region 1031 is suspended, preventing the light-transmitting cover 107 from contacting the surface of the active region 1031. An adhesive 108 is provided at the position where the light-transmitting cover 107 overlaps with the top surface of the encapsulation body 106, and the adhesive 108 fixes the light-transmitting cover 107 to a position above the active region 1031. In some embodiments, the material of the adhesive 108 may be an ethylene-vinyl acetate copolymer.

[0068] Figure 2 A cross-sectional schematic diagram illustrating the manufacturing process of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown.

[0069] like Figure 2 As shown, firstly, in step S1, the circuit board 102 is fixed to one end of the top surface of the substrate 101. Specifically, a portion of the back side of the circuit board 102 is fixed to the substrate 101 with adhesive, and another portion extends beyond the substrate 101.

[0070] Next, in step S2, the micro LED chip 103 is fixed to the top surface of the substrate 101. Specifically, the micro LED chip 103 is fixed to the substrate 101 with adhesive, and the micro LED chip 103 is adjacent to the circuit board 102.

[0071] Next, in step S3, a lead 105 is formed between the circuit board 102 and the micro LED chip 103 using a wire bonding process. The circuit board 102 is connected to the driving circuit of the micro LED chip 103 via the lead 105.

[0072] Next, in step S4, an injection molding process is performed to form a molding compound 106. The molding compound 106 is disposed around the micro-LED chip 103, exposing the active region 1031 of the micro-LED chip 103. Specifically, the molding compound 106 covers all sides of the micro-LED chip 103, a portion of its top surface (excluding the active region 1031), the top and side surfaces of the circuit board 102 adjacent to the micro-LED chip 103, and a portion of the top surface of the substrate 101. The molding compound 106 covers the leads 105 to provide insulation protection for the leads 105. The area above the active region of the micro-LED chip 103 is not covered by the molding compound 106.

[0073] In step S5, a light-transmitting cover plate 107 is placed over the active region of the micro LED chip 103. Specifically, the top surface of the molding compound 106 is higher than the surface of the active region. The light-transmitting cover plate 106 has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surface of the molding compound 106, and there is a gap between the bottom surface of the central region and the surface of the active region 1031. Therefore, when the light-transmitting cover plate 107 is placed, its periphery is supported on the top surface of the molding compound 106. Adhesive 108 is present at the overlap between the light-transmitting cover plate 107 and the top surface of the molding compound 106, and the light-transmitting cover plate 107 is fixed by the adhesive 108.

[0074] Figure 3 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown. Figure 3 The micro LED chip packaging structure shown is similar to Figure 1The main difference in the structure shown lies in the shape and position of the molding compound 306 and the light-transmitting cover 307. The substrate 301, circuit board 302, micro LED chip 303, and leads 305 are... Figure 1 The corresponding structures shown are similar, and will not be described again for the sake of simplicity.

[0075] like Figure 3 As shown, the molding compound 306 is disposed around the micro LED chip 303 and exposes the active region of the micro LED chip 303. In other words, the molding compound 306 covers all sides of the micro LED chip 303 and part of its top surface except for the active region, the top and side surfaces of the circuit board 302 adjacent to the micro LED chip 303, and part of the top surface of the substrate 301. The molding compound 306 covers the lead wire 305 to provide insulation protection for the lead wire 305. The active region of the micro LED chip 303 is not covered by the molding compound 306. A downward molding step 310 is formed in the portion of the molding compound 306 adjacent to the active region of the micro LED chip 303, such that the top surface 3101 of the molding step 310 is lower than the top surface 3601 of the other parts of the molding compound 306. In other words, in the area of ​​the plastic-encapsulated step 310, the top surface of the plastic-encapsulated body 306 drops from a first height to a second height, and the difference between the first height and the second height is the height of the plastic-encapsulated step 310.

[0076] In some embodiments of the present invention, the top surface height of the molding step 310 is higher than the surface height of the active region. The light-transmitting cover plate 307 has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surface of the molding step 310, and there is a gap between the bottom surface of the central region and the surface of the active region. That is, the light-transmitting cover plate 307 is supported on the top surface of the molding step 310 around its perimeter, while the portion directly opposite the active region is suspended, thereby preventing the light-transmitting cover plate 307 from contacting the surface of the active region. An adhesive 308 is provided at the position where the light-transmitting cover plate 307 overlaps with the top surface of the molding step 310, and the light-transmitting cover plate 307 is fixed above the active region by the adhesive 308.

[0077] In some embodiments of the present invention, a molding opening is formed above the active region of the micro LED chip 303 not covered by the molding compound 306. A molding step 310 surrounds the molding opening to form a support area for a light-transmitting cover 307. The edge of the molding step 310 is equal to or slightly larger than the outer edge of the light-transmitting cover 307, allowing the light-transmitting cover 307 to be accommodated within the recessed area formed by the molding step 310. The height of the molding step 310 is substantially equal to the sum of the thicknesses of the light-transmitting cover 307 and the adhesive 308, making the top surface of the light-transmitting cover 307 substantially flush with the top surface 3061 of the molding compound 306, thereby reducing the overall thickness of the package. Figure 1 Compared to the packaging structure shown, Figure 3 The package thickness of the embodiment shown is reduced by approximately 0.1 mm.

[0078] In other embodiments of the present invention, the top surface of the light-transmitting cover 307 may be higher or lower than the top surface 3061 of the molding compound 306.

[0079] Figure 4 A cross-sectional schematic diagram illustrating the manufacturing process of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown. Figure 4 The manufacturing process of the micro LED chip packaging structure shown is similar to Figure 2 The main difference in the structure shown lies in steps S4 and S5. Steps S1 to S3 are different from... Figure 2 The corresponding steps shown are similar, and will not be repeated for the sake of simplicity.

[0080] like Figure 4 As shown, in step S4, an injection molding process is performed to form a molding compound 306. The molding compound 306 is disposed around the micro-LED chip 303, exposing the active region of the micro-LED chip 303. In other words, the molding compound 306 covers all sides of the micro-LED chip and part of its top surface (excluding the active region), the top and side surfaces of the circuit board adjacent to the micro-LED chip, and part of the top surface of the substrate. The molding compound 306 covers the leads to provide insulation protection. The portion of the molding compound 306 adjacent to the active region of the micro-LED chip has a downward molding step. In the molding step region, the top surface of the molding compound 306 decreases from a first height to a second height, and the difference between the first height and the second height is the height of the molding step.

[0081] In step S5, a light-transmitting cover plate 307 is placed over the active area of ​​the micro LED chip. The top surface of the molding step 310 is higher than the surface height of the active area. The light-transmitting cover plate 307 has a central area corresponding to the active area and a support area located around the central area. The support area covers and is fixed to the surface of the molding step 310, and there is a gap between the bottom surface of the central area and the surface of the active area. Specifically, a molding opening is formed above the active area of ​​the micro LED chip 303 not covered by the molding body 306. The molding step surrounds the molding opening to form the support area of ​​the light-transmitting cover plate. The edge of the molding step 310 is slightly larger than the outer edge of the light-transmitting cover plate 307, so that the light-transmitting cover plate 307 can be accommodated in the recessed area formed by the molding step 310. The light-transmitting cover plate 307 is fixed to the top surface of the molding step 310 with adhesive.

[0082] Figure 5 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown. Figure 5 The micro LED chip packaging structure shown is similar to Figure 1 The main difference in the structure shown lies in the position of the light-transmitting cover 507. The substrate 501, circuit board 502, micro LED chip 503, lead wire 505, and molding compound 506 are different from those shown. Figure 1 The corresponding structures shown are similar, and will not be described again for the sake of simplicity.

[0083] like Figure 5 As shown, the molding compound 506 is disposed around the micro LED chip 503, exposing the active region 5031 of the micro LED chip 503. In some embodiments of the present invention, a molding window is formed above the active region of the micro LED chip 503 not covered by the molding compound 506, and a light-transmitting cover plate 507 is disposed within the molding window above the active region 5031 of the micro LED chip. The top surface of the light-transmitting cover plate 507 is flush with the top surface of the molding compound 506. In other embodiments of the present invention, the top surface of the light-transmitting cover plate 507 may be higher or lower than the top surface of the molding compound 506.

[0084] In an embodiment of the present invention, the light-transmitting cover plate 507 has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surrounding surface of the active region 5031. A gap exists between the bottom surface of the central region and the surface of the active region 5031. An adhesive 508 is provided at the position where the light-transmitting cover plate 507 overlaps with the outer top surface of the active region 5031. The adhesive 508 fixes the light-transmitting cover plate 507 to a position above the active region. The top surface of the adhesive 508 is higher than the surface of the active region 5031, thereby preventing the light-transmitting cover plate 507 from contacting the surface of the active region 5031.

[0085] Figure 5 The manufacturing method of the micro LED chip packaging structure shown is similar to Figure 2 The manufacturing method shown is similar, except that the final step involves fixing the transparent cover plate 507 to the top surface of the active region 5031 around the perimeter using adhesive.

[0086] Figure 6 A cross-sectional schematic diagram of a micro light-emitting diode chip package structure according to an embodiment of the present invention is shown. Figure 6 The micro LED chip packaging structure shown is similar to Figure 1 The main difference in the structure shown lies in the shape of the light-transmitting cover 607. The substrate 601, circuit board 602, micro LED chip 603, lead wire 605, and encapsulation 606 are similar to... Figure 1 The corresponding structures shown are similar, and will not be described again for the sake of simplicity.

[0087] like Figure 6 As shown, a plastic-encapsulated window is formed above the active region of the micro LED chip 603 not covered by the plastic encapsulation body 606. The light-transmitting cover 607 has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surface of the plastic encapsulation body 606, and the thickness T1 of the support region is less than the thickness T2 of the central region. That is, the top surface of the light-transmitting cover 607 is flat, and the central region of the bottom surface protrudes downward relative to the support region to form a boss, which extends downward into the plastic-encapsulated window. There is a gap between the bottom surface of the boss and the surface of the active region 6031. Adhesive 608 is provided at the overlapping position of the light-transmitting cover 607 and the plastic encapsulation body 606, and the light-transmitting cover 607 is fixed above the active region by the adhesive 608.

[0088] The central area of ​​the light-transmitting cover 607 is thicker, while the supporting area is thinner. The advantage of this structure is that it can achieve good overall strength of the packaging structure while reducing the overall thickness of the packaging.

[0089] Figure 6 The manufacturing method of the micro LED chip packaging structure shown is similar to Figure 2 The manufacturing method shown is similar, except that in the final step, the supporting area of ​​the transparent cover plate 607 is fixed to the top surface of the plastic seal 606 by adhesive, and the protrusion in the middle area extends into the plastic seal window.

[0090] The above embodiments of the present invention provide a packaging structure for a micro light-emitting diode (LED) chip and a method for manufacturing the same. Compared with the packaging structure of existing micro LED chips, the embodiments of the present invention provide a light-transmitting cover plate above the active region of the micro LED chip, increasing the protection of the active region and improving the overall strength of the package. Furthermore, in the embodiments of the present invention, the light-transmitting cover plate can be disposed on the molding step, which can reduce the overall thickness of the package while ensuring its overall strength.

[0091] Although various embodiments of the invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made without departing from the spirit and scope of the invention. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A packaging structure for a miniature light-emitting diode chip, characterized in that, include: substrate; A circuit board disposed on the top surface of the substrate; A miniature light-emitting diode chip is disposed on the top surface of the substrate. A first surface of the miniature light-emitting diode chip is connected to the substrate, and an active area is provided on a second surface of the miniature light-emitting diode chip opposite to the first surface. The circuit board is electrically connected to the miniature light-emitting diode chip. A molding compound, wherein the molding compound is disposed around the micro LED chip and exposes the active region of the micro LED chip; and A light-transmitting cover plate is disposed over the active region of the micro light-emitting diode chip.

2. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, One portion of the back of the circuit board is fixed to the substrate by circuit board adhesive, and another portion extends beyond the substrate.

3. The packaging structure of the micro light-emitting diode chip as described in claim 2 is characterized in that, The circuit board has an extension line interface at one end that extends beyond the substrate.

4. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, All sides of the substrate extend beyond the coverage area of ​​the micro LED chip; or At least a portion of the sides of the substrate does not extend beyond the coverage area of ​​the micro LED chip.

5. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, Its features are, The substrate includes a copper substrate, an Invar steel substrate, or a ceramic substrate.

6. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The circuit board includes a flexible circuit board or a printed circuit board.

7. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The encapsulation material includes epoxy resin, silicone, or ethylene-vinyl acetate copolymer.

8. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The miniature light-emitting diode chip is electrically connected to the circuit board via leads, and the plastic encapsulation covers the leads.

9. The packaging structure of the micro light-emitting diode chip as described in claim 8, characterized in that, The edge region of the second side of the micro LED chip is provided with a first connection portion, and the surface of the circuit board away from the substrate is provided with a second connection portion, wherein the lead connects the first connection portion and the second connection portion.

10. The packaging structure of the micro light-emitting diode chip as described in claim 8, characterized in that, The lead wire is made of gold or aluminum.

11. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The first side of the micro LED chip is fixed to the substrate by a chip adhesive, the material of which includes conductive adhesive, silver paste, or die bonding film.

12. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The micro LED chip includes an integrated circuit backplane and an active region disposed on the integrated circuit backplane. The active region includes a pixel array formed by micro LEDs. The pixel array includes a plurality of micro LED pixels, and each pixel includes one or more micro LEDs.

13. The packaging structure of the micro light-emitting diode chip as described in claim 12, characterized in that, The micro-LED includes a micrometer-scale light-emitting mesa structure, which comprises a first type epitaxial layer, a second type epitaxial layer, and a light-emitting layer between the first type epitaxial layer and the second type epitaxial layer. The first type of epitaxial layer is a semiconductor material having a first conductivity type and includes multiple semiconductor layers; The second type of epitaxial layer is a semiconductor material having a second conductivity type and includes multiple semiconductor layers.

14. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, There is a gap between the bottom surface of the light-transmitting cover and the surface of the active area.

15. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The materials of the light-transmitting cover include: glass, silicon dioxide, or magnesium fluoride.

16. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The top surface of the encapsulation is higher than the top surface of the active region. The light-transmitting cover has a middle region corresponding to the active region and a support region located around the middle region. The support region covers and is fixed to the surface of the encapsulated body. There is a gap between the bottom surface of the middle region and the surface of the active region.

17. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The portion of the encapsulation body adjacent to the active region of the micro LED chip forms a downward encapsulation step. The top surface of the encapsulation step is lower than the top surface of the encapsulation body. The light-transmitting cover has a middle region corresponding to the active region and a support region located around the middle region. The support region covers and is fixed to the surface of the encapsulation step. There is a gap between the bottom surface of the middle region and the surface of the active region.

18. The packaging structure of the micro light-emitting diode chip as described in claim 17, characterized in that, The top surface of the plastic-sealed step is higher than the surface height of the active area.

19. The packaging structure of the micro light-emitting diode chip as described in claim 18, characterized in that, The light-transmitting cover plate overlaps with the top surface of the plastic-sealed step at a location where the light-transmitting cover plate is bonded with adhesive. The light-transmitting cover plate is then fixed in place by the adhesive, positioning it above the active area.

20. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The light-transmitting cover has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surrounding surface of the active region. There is a gap between the bottom surface of the central region and the surface of the active region.

21. The packaging structure of the micro light-emitting diode chip as described in claim 17 or 20, characterized in that, The top surface of the light-transmitting cover is flush with the top surface of the plastic seal.

22. The packaging structure of the micro light-emitting diode chip as described in claim 1, characterized in that, The light-transmitting cover has a central region corresponding to the active region and a support region located around the central region. The support region covers and is fixed to the surface of the encapsulated body. There is a gap between the bottom surface of the central region and the surface of the active region. The top surface of the light-transmitting cover is flat, and the bottom surface of the central region protrudes downward relative to the bottom surface of the support region to form a boss. The boss extends downward into the encapsulated window above the active region that is not covered by the encapsulated body.

23. The packaging structure of the micro light-emitting diode chip as described in claim 16 or 22, characterized in that, The light-transmitting cover plate overlaps with the top surface of the plastic sealant at a location where it is bonded with adhesive. The light-transmitting cover plate is then fixed in place by the adhesive, positioning it above the active area.

24. The packaging structure of the micro light-emitting diode chip as described in claim 19 or 23, characterized in that, The adhesive material for the light-transmitting cover is ethylene-vinyl acetate copolymer.

25. A method for manufacturing a packaging structure for a micro light-emitting diode chip, characterized in that, include: Fix the circuit board to one end of the top surface of the substrate; The miniature light-emitting diode chip is fixed on the top surface of the substrate; A wire bonding process is used to form leads between the circuit board and the micro LED chip. A molding compound is formed, wherein the molding compound encapsulates the micro LED chip; A light-transmitting cover is placed over the active area of ​​the micro LED chip.

26. The method for manufacturing the packaging structure of the micro light-emitting diode chip as described in claim 25, characterized in that, The top surface of the encapsulation is higher than the top surface of the active region, and the light-transmitting cover has a central region corresponding to the active region and a supporting region located around the central region. The supporting area is covered and fixed to the surface of the encapsulated body by a light-transmitting cover adhesive, and there is a gap between the bottom surface of the middle area and the surface of the active area.

27. The method for manufacturing the packaging structure of the micro light-emitting diode chip as described in claim 25, characterized in that, A downward molding step is formed at the portion of the molding compound adjacent to the active region of the micro LED chip. The top surface of the molding step is lower than the top surface of the molding compound. The light-transmitting cover has a central region corresponding to the active region and a support region located around the central region. The supporting area is covered and fixed to the surface of the plastic-sealed step by a light-transmitting cover adhesive, and there is a gap between the bottom surface of the middle area and the surface of the active area.

28. The method for manufacturing the packaging structure of the micro light-emitting diode chip as described in claim 25, characterized in that, The light-transmitting cover plate has a central region corresponding to the active region and a supporting region located around the central region. The supporting area is covered and fixed to the surrounding surface of the active area by a light-transmitting cover adhesive, and there is a gap between the bottom surface of the middle area and the surface of the active area.

29. The method for manufacturing the packaging structure of the micro light-emitting diode chip as described in claim 25, characterized in that, The light-transmitting cover plate has a central region corresponding to the active region and a supporting region located around the central region. The supporting area is covered and fixed to the surface of the encapsulated body by a light-transmitting cover adhesive. There is a gap between the bottom surface of the middle area and the surface of the active area. The top surface of the light-transmitting cover is flat, and the middle area of ​​the bottom surface protrudes downward relative to the supporting area to form a boss. The boss extends downward into the encapsulated window above the active area that is not covered by the encapsulated body.

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