LED lamp driving package structure and manufacturing method thereof

Abstract

The present disclosure relates to the technical field of display, and provides an LED lamp driving and sealing packaging structure and a manufacturing method thereof. The LED lamp driving and sealing packaging structure comprises: a driving chip having an active surface and a bottom surface opposite to the active surface, and a plurality of first pads are arranged on the active surface; at least one LED chip is mounted on the driving chip and electrically connected with the driving chip; a re-wiring layer is arranged on the active surface side of the driving chip, and the re-wiring layer comprises a plurality of redistribution wires, one end of each redistribution wire is electrically connected with a corresponding first pad, and the other end of each redistribution wire extends along the sidewall of the driving chip to a first position horizontally flat with the bottom surface of the driving chip; and a plurality of interconnection bumps are respectively arranged on the first positions and electrically connected with the other ends of the redistribution wires. The scheme adopts the laminated packaging of the LED chip and the driving IC chip, and utilizes the re-wiring process to realize the quasi-3D structure packaging, so that the volume of the packaging structure can be reduced, the shielding of the driving chip to the LED can be reduced, and the system cost can be effectively reduced.

Description

Technical Field

[0001] This disclosure relates to the field of LED display technology, and in particular to an LED lamp driver encapsulation structure and its manufacturing method. Background Technology

[0002] In the field of Mini-LED / Micro-LED display technology, various technical approaches have been developed to achieve high brightness, high luminous efficiency, and ultra-thin designs. For example, AM-driven Mini-LED backlighting technology can significantly improve the black-and-white contrast ratio of TVs or monitors, achieving a higher HDR (High Dynamic Range). Besides high contrast, high color gamut display has also become a major focus for the next generation of high-end display devices. Especially for the BT.2020 standard, which covers a wider color range, RGB three-primary-color and even RGBX multi-primary-color LEDs are gradually replacing traditional blue or white LED backlight sources, becoming the next generation of backlight module technology for displays. Besides achieving near- or even exceeding 100% BT.2020 color gamut standards when combined with TFT LCDs and CF (Color Filter), RGB-Mini LED backlighting can also be paired with CF-free LCD technology in the future. FSC (Field Sequential Color) applications can achieve more than three times the luminous efficacy compared to CF-equipped LCDs. This technology demands extremely high LCD response speeds and is prone to color splitting. Currently, high refresh rate LCD panels and display circuit systems are under development and optimization. Additionally, pixel-level beam splitting solutions such as Mini-LED and Micro-LED direct-view displays also eliminate the need for CF, significantly improving luminous efficacy, but requiring stringent assembly precision for micro / nano optical structures. All of these solutions require high-density integration of RGB light-emitting chips and driver chips to achieve precise pixel-level control. Quasi-3D lamp-driver stacking and encapsulation technology, where LED chips are bonded to the driver IC chip, avoids the blocking of light emission from the LED chip by the driver chip in 2D packaging structures, achieving a wider light emission angle, reducing the need for secondary optical lenses, and thus achieving a thinner backlight thickness. Employing RDL (Redistribution Layer) technology and chip-level packaging technology, it is also smaller in size than traditional plastic bracket packaging, reducing the number of packaging layers and materials, resulting in a smaller package size and greater cost advantage.

[0003] In existing lamp driver packaging structures, the driver chip typically uses wire bonding to bring its pads to the package substrate or external circuitry. However, the bonding wires require a certain curvature, leading to an increase in overall package thickness and volume, which is detrimental to ultra-thin designs. Another common approach is to use TSV (Through Silicon Via) technology, which creates vertical conductive channels inside the driver chip, bringing the pads from the active side to the back side, and then placing BGA (Ball Grid Array) solder balls. While TSV technology can reduce package size, its process is complex, requiring multiple high-precision steps such as deep hole etching, insulating layer deposition, metal filling, and chemical mechanical polishing, resulting in high equipment costs. It is more suitable for high-precision, high-I / O-density AI chips or advanced IC products. Furthermore, it is prone to introducing leakage current and thermal stress reliability issues, placing extremely high demands on packaging and testing. In summary, the current method of bringing the driver chip out of the package via pads cannot simultaneously meet the requirements of small size and low cost. Summary of the Invention

[0004] In view of this, the present disclosure provides an LED driver stacked encapsulation packaging structure and its manufacturing method to solve the technical problem that the existing driver chip pad lead-out packaging cannot simultaneously meet the requirements of size and cost.

[0005] To achieve the above objectives, the technical solution adopted in this disclosure is: A first aspect of this disclosure provides an LED driver encapsulation package structure. The LED driver encapsulation package structure includes: a driver chip having an active surface and a bottom surface opposite to the active surface, the active surface having a plurality of first pads; at least one LED chip mounted on the driver chip and electrically connected to the driver chip; a redistribution layer disposed on one side of the active surface of the driver chip, the redistribution layer including a plurality of redistribution wires, one end of each redistribution wire being electrically connected to a corresponding first pad, and the other end extending along the sidewall of the driver chip to a first position horizontally flush with the bottom surface of the driver chip; and a plurality of interconnect bumps respectively disposed at the first position and electrically connected to the other end of the redistribution wires.

[0006] In some embodiments, the LED chip includes a flip-chip LED, which is mounted on the active surface of the driver chip using solder or copper-to-copper bonding.

[0007] In some embodiments, the redistribution layer includes at least one metal layer, and the redistribution layer completes the chip-scale packaging of the LED driver through a fan-out redistribution process; an insulating layer is disposed between the redistribution layer and the driver chip, and the insulating layer includes epoxy resin, silicone resin, polyimide, BCB, polyimide or benzocyclobutene.

[0008] In some embodiments, at least one LED chip includes a red light chip, a green light chip, and a blue light chip; or, the at least one LED chip includes a red light chip, a green light chip, a blue light chip, and an X chip, wherein the X chip includes a cyan chip, a yellow chip, or another fourth primary color chip; or, the at least one LED chip includes multiple Micro-LEDs arranged in an array after being connected in series.

[0009] In some embodiments, an encapsulating colloid is further included, which encapsulates the LED chip and at least a portion of the driver chip, with multiple interconnect bumps exposed from the encapsulating colloid; wherein the interconnect bumps include copper layers, copper pads, solder pads, or solder balls.

[0010] A second aspect of this disclosure provides a method for manufacturing an LED driver encapsulation structure, comprising the following steps: providing a driver chip and thinning the bottom surface of the driver chip, wherein the active surface of the driver chip is provided with a plurality of first pads; providing a temporary carrier board and placing the driver chip on the temporary carrier board with its active surface facing or away from the temporary carrier board; forming a redistribution layer, wherein the redistribution layer electrically connects the first pads of the driver chip to a first position on the upper surface of the temporary carrier board; mounting at least one LED chip above the driver chip and electrically connecting the LED chip and the driver chip by soldering or copper-copper thermoforming; performing silicone molding to form a planar optical structure or a curved optical structure that meets the light emission angle requirements to protect the LED chip and the driver chip; removing the temporary carrier board to expose the first position; forming interconnect bumps on the first position and cutting to obtain a die-form encapsulation structure.

[0011] In some embodiments, prior to forming the redistribution layer, the method further includes: molding an insulating material over a temporary carrier and a driver chip, grinding the insulating material to expose a first pad, and laser-perforating the insulating material to a first location.

[0012] A third aspect of this disclosure provides a method for manufacturing an LED driver encapsulation package structure, comprising the following steps: providing a driver chip and thinning the bottom surface of the driver chip, wherein the active surface of the driver chip is provided with a plurality of first pads; mounting at least one LED chip on top of the driver chip and electrically connecting the LED chip and the driver chip by soldering or copper-copper thermoforming; providing a temporary carrier board and placing the driver chip with the LED chip mounted thereon on the temporary carrier board with its active surface facing or away from the temporary carrier board; forming a redistribution layer, wherein the redistribution layer electrically connects the first pads of the driver chip to a first position on the upper surface of the temporary carrier board; removing the temporary carrier board to expose the first position; and forming interconnect bumps at the first position to obtain the encapsulation structure.

[0013] In some embodiments, forming a redistribution layer includes forming the redistribution layer by sputtering, photolithography, electroplating, and etching processes.

[0014] In some embodiments, before forming the redistribution layer, the method further includes: forming an insulating layer along the sidewall of the driver chip between the first pad of the driver chip and a temporary carrier board, and grinding the insulating layer to expose the first pad.

[0015] The beneficial effects of the embodiments disclosed herein compared with the prior art include: the technical solution of the embodiments disclosed herein extends the redistribution wires along the sidewall of the driver chip to a first position flush with the bottom surface, and sets copper pillars, solder pads or BGA solder balls at the position to bring out the input / output ports of the package structure; this avoids the problem of excessive package thickness and volume caused by the use of bonding wires, and also avoids the high cost problem caused by the use of TSV through-hole process, thereby reducing the thickness of the lamp driver encapsulation package structure and reducing its cost. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of an LED driver encapsulation structure according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the driver IC disk being laid out on a temporary carrier board in an embodiment of this disclosure; Figure 3 This is a schematic diagram of the molded insulating material and perforated in an embodiment of this disclosure; Figure 4 This is a schematic diagram of sputtering after the seed layer of the wiring layer in an embodiment of this disclosure; Figure 5 This is a schematic diagram of the copper plating process in an embodiment of this disclosure; Figure 6 This is a schematic diagram after removing the photoresist and seed layer in an embodiment of this disclosure; Figure 7 This is a schematic diagram of the LED chip after welding in an embodiment of this disclosure; Figure 8 This is a schematic diagram of the silicone layer after molding in an embodiment of this disclosure; Figure 9 This is a schematic diagram of the temporary carrier plate after removal in an embodiment of this disclosure; Figure 10This is a flowchart illustrating a method for manufacturing an LED driver encapsulation structure according to an embodiment of this disclosure. Figure 11 This is a schematic diagram of the driver chip wafer after a protective layer has been coated in an embodiment of this disclosure; Figure 12 This is a schematic diagram of the light-emitting chip being mounted onto the thinned driver chip wafer in an embodiment of this disclosure; Figure 13 This is a schematic diagram of the driver chip wafer being cut and arranged onto a temporary carrier board in an embodiment of this disclosure; Figure 14 This is a schematic diagram showing the exposed pads after the photoresist has been exposed in an embodiment of this disclosure; Figure 15 This is a schematic diagram showing the insulation layer and rewiring layer formed in an embodiment of this disclosure; Figure 16 This is a schematic diagram showing the process after removing the protective layer and forming a transparent silicone layer in an embodiment of this disclosure; Figure 17 This is a schematic diagram of the packaging structure after being cut in an embodiment of this disclosure; Figure 18 This is a schematic diagram of the driver chip wafer after the light-emitting chip is mounted in an embodiment of this disclosure; Figure 19 This is a schematic diagram of a single grain in an embodiment of this disclosure; Figure 20 This is a schematic diagram of another single grain in an embodiment of this disclosure; Figure 21 This is a schematic diagram of another LED driver encapsulation packaging structure in an embodiment of this disclosure; Figure 22 This is a schematic diagram of another LED driver encapsulation structure in an embodiment of this disclosure. Detailed Implementation

[0018] To make the technical problems, technical solutions, and beneficial effects to be solved by this disclosure clearer, the disclosure will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining this disclosure and are not intended to limit this disclosure.

[0019] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly or indirectly located on that other component. When a component is referred to as "connected to" another component, it can be directly or indirectly connected to that other component. The terms "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or position based on the accompanying drawings, and are for ease of description only, and should not be construed as limiting the technical solution. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. "A plurality of" means two or more, unless otherwise explicitly defined.

[0020] The following will describe in detail, with reference to the accompanying drawings, the packaging structure and manufacturing method of the LED driver encapsulation according to embodiments of the present disclosure.

[0021] Figure 1 This is a schematic diagram of an LED driver encapsulation structure according to an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the driver IC disk being laid out on a temporary carrier board in an embodiment of this disclosure; Figure 3 This is a schematic diagram of the molded insulating material and perforated in an embodiment of this disclosure; Figure 4 This is a schematic diagram of sputtering after the seed layer of the wiring layer in an embodiment of this disclosure; Figure 5 This is a schematic diagram of the copper plating process in an embodiment of this disclosure; Figure 6 This is a schematic diagram after removing the photoresist and seed layer in an embodiment of this disclosure; Figure 7 This is a schematic diagram of the LED chip after welding in an embodiment of this disclosure; Figure 8 This is a schematic diagram of the silicone layer after molding in an embodiment of this disclosure; Figure 9 This is a schematic diagram of the temporary carrier plate after removal in an embodiment of this disclosure; Figure 10 This is a flowchart illustrating a method for manufacturing an LED driver encapsulation structure according to an embodiment of this disclosure. Figure 11 This is a schematic diagram of the driver chip wafer after a protective layer has been coated in an embodiment of this disclosure; Figure 12 This is a schematic diagram of the light-emitting chip being mounted onto the thinned driver chip wafer in an embodiment of this disclosure; Figure 13 This is a schematic diagram of the driver chip wafer being cut and arranged onto a temporary carrier board in an embodiment of this disclosure; Figure 14 This is a schematic diagram showing the exposed pads after the photoresist has been exposed in an embodiment of this disclosure; Figure 15 This is a schematic diagram showing the insulation layer and rewiring layer formed in an embodiment of this disclosure; Figure 16 This is a schematic diagram showing the process after removing the protective layer and forming a transparent silicone layer in an embodiment of this disclosure; Figure 18This is a schematic diagram of the driver chip wafer after the light-emitting chip is mounted in an embodiment of this disclosure; Figure 19 This is a schematic diagram of a single grain in an embodiment of this disclosure; Figure 20 This is a schematic diagram of another single grain in an embodiment of this disclosure; Figure 21 This is a schematic diagram of another LED driver encapsulation packaging structure in an embodiment of this disclosure; Figure 22 This is a schematic diagram of another LED driver encapsulation structure in an embodiment of this disclosure. The following is in conjunction with... Figures 1 to 22 The present disclosure describes the LED driver encapsulation structure and its manufacturing method according to the embodiments provided.

[0022] like Figure 1 As shown, the LED driver encapsulation structure provided in this embodiment includes: a driver chip 310 having an active surface and a bottom surface opposite to the active surface, with a plurality of first pads 311 on the active surface; at least one LED chip mounted on the driver chip and electrically connected to the driver chip; a redistribution layer disposed on one side of the active surface of the driver chip, the redistribution layer including a plurality of redistribution wires, one end of each redistribution wire being electrically connected to a corresponding first pad, and the other end extending along the sidewall of the driver chip to a first position level with the bottom surface of the driver chip; and a plurality of interconnect bumps (not shown in the figure) respectively disposed at the first position and electrically connected to the other end of the redistribution wires. The redistribution layer includes a seed layer 340 and an electroplating layer 360, both of which can be copper metal layers. The former can be a sputtered Ti (titanium) and Cu (copper) metal layer, and the latter can be an electroplated or electroless plated Cu (copper) metal layer. The electroplating copper process in this embodiment is only an exemplary description; the electroplating layer can also be formed by an electroless copper plating process.

[0023] The technical solution of this disclosure extends the redistribution wires along the sidewall of the driver chip to a first position flush with the bottom surface and directly sets copper pillars, solder pads, or BGA solder balls, avoiding the use of bonding wires and TSV vias, thereby forming an ultra-thin, low-cost lamp driver encapsulation structure.

[0024] In actual manufacturing, the thickness of the driver chip 310, after thinning treatment, can be controlled within the range of 50μm to 180μm, preferably 80μm to 100μm, to balance mechanical strength and thinness requirements. The material of the first pad 311 on the active surface of the driver chip can be aluminum or copper. The redistributed conductors in the redistribution layer can be made of copper. The interconnect bumps can be BGA solder balls, with a diameter typically of 0.1mm to 0.5mm and a solder ball spacing of 0.2mm to 0.8mm, ensuring good soldering with the external circuit board. In addition, the interconnect bumps can also be copper pillars, copper layers, copper pads, solder pads, or solder balls.

[0025] In this embodiment, the "first position level with the bottom surface of the driver chip" refers to the height position of the end of the redistribution conductor extending along the sidewall of the driver chip, which is exactly at the same level as the bottom surface of the driver chip. Since the bottom surface of the driver chip is a flat surface, this first position is actually located on the boundary line between the sidewall and the bottom surface or in the sidewall area immediately adjacent to the boundary line. This design allows the interconnect bumps to be directly set on the lower side of the driver chip without occupying additional bottom surface area, thereby achieving a fan-out structure with zero increase in projected area, making full use of the height direction of the chip sidewall, and further compressing the package area.

[0026] like Figure 1 As shown, at least one LED chip includes a red chip 121, a green chip 122, and a blue chip 123. In practical selection, the red chip can use an AlGaInP material system with an emission wavelength of 620nm–630nm; the green and blue chips can use an InGaN material system, with green light wavelengths of 520nm–530nm and blue light wavelengths of 450nm–460nm. The three chips can have the same or different sizes. The typical size of a single chip depends on the LED package size and power consumption, and can be 50μm×100μm, 100μm×200μm, 250μm×750μm, or even larger. The chip shape can be square or rectangular. To obtain a better light mixing effect, the three chips can be arranged closely in a straight line, with the spacing between them generally ranging from 50μm to 200μm, depending on the chip size and package size requirements. This disclosure does not limit the specific arrangement of the LED chips, as long as full-color display can be achieved. By integrating three independent light-emitting chips—red, green, and blue—full-color display can be realized, meeting the requirements of Mini-LED / Micro-LED displays for independent control of the three primary colors, avoiding the use of color filters, and improving luminous efficiency and color performance. However, in practical applications, at least one LED chip is not limited to including one red chip, one green chip, and one blue chip; other combinations are also possible as needed.

[0027] like Figure 1 The LED chip shown can be a flip-chip LED, which is mounted on the active surface of the driver chip using solder or copper-to-copper bonding. In other embodiments, the LED chip is mounted on the active surface of the driver chip using wire bonding. Figure 1 In the flip-chip mounting method shown, the LED chip is directly bonded to the second pad on the active surface of the driver chip via metal bumps. The solder bump solution can employ a flip-chip bonding process, where solder is pre-placed on the pads of the driver chip, the LED chip is then inverted and aligned, and reflow soldering is used to melt the solder and form a reliable electrical and mechanical connection.

[0028] In the technical solutions of this disclosure, the LED chip and driver chip are arranged in a stacked manner, which can reduce the packaging structure of LED lamp driver and avoid the driver chip blocking the light emitted by the LED chip. The LED chip and driver chip can adopt any of the above-mentioned electrical connection methods. Among them, flip-chip mounting can further shorten the interconnection path and reduce parasitic parameters, while wire bonding can be compatible with traditional processes, improving the process flexibility and applicability of the packaging structure.

[0029] In this embodiment of the disclosure, the redistribution layer includes at least one metal layer, and the redistribution layer completes the chip-level packaging of the LED driver through a fan-out redistribution process; an insulating layer is disposed between the redistribution layer and the driver chip, and the insulating layer includes epoxy resin, silicone resin, polyimide, BCB, polyimide or benzocyclobutene.

[0030] By setting an insulating layer 320 between the redistribution layer and the driver chip, electrical insulation between the wires and the chip surface is achieved; insulating layer materials such as polyimide or benzocyclobutene have good planarization properties and good flowability, which can simplify the manufacturing process of RDL.

[0031] In this embodiment, the LED driver encapsulation structure further includes an encapsulating colloid 390, which covers the LED chip and at least part of the driver chip, with multiple interconnect bumps exposed from the encapsulating colloid. The encapsulating colloid can be transparent silicone, but is not limited to this. By encapsulating the LED chip and driver chip with the colloid, the mechanical strength and reliability of the encapsulation structure can be improved. Simultaneously, the exposed interconnect bumps ensure proper soldering of the LED driver encapsulation structure to the external circuitry.

[0032] In addition to transparent silicone, the encapsulating colloid 390 can also be made of epoxy resin molding compound or silicone molding compound. When used for transparent displays or side-emitting applications, the encapsulating colloid should have high light transmittance and low haze; if it is necessary to change the light emission angle, light scattering particles can be added to the colloid. During the manufacturing process, the encapsulating colloid can be formed by dispensing, compression molding, or jet molding processes, and its coverage thickness should be at least 25μm above the top of the LED chip to provide adequate protection.

[0033] The present disclosure discloses a method for fabricating an LED driver encapsulation structure, which involves first forming a wiring layer and then mounting the LED chip. This method can sequentially obtain the following... Figure 2 As for Figure 9 The structure. Specifically, the manufacturing method includes the following steps: A driver chip is provided, which can be obtained by cutting a driver IC wafer after the front side is coated with a protective layer, and the bottom side (i.e., the back side) of the driver chip is thinned and the wafer is cut, on the active surface of the driver chip.

[0034] The cut driver IC disk is placed onto a temporary carrier board and fixed using heat-release adhesive applied to the temporary carrier board, resulting in the following: Figure 2 The structure shown. (As illustrated) Figure 2 As shown, a driver chip 310 is disposed above the temporary carrier board 380, and the driver chip has a first pad 311 and a second pad 301.

[0035] Insulating materials such as epoxy resin are molded onto the temporary carrier board and the driver chip. The insulating material is then ground to expose the copper pads (the first pads) on the surface of the driver IC. Laser perforation is then performed on the insulating material to the first position on the temporary carrier board, resulting in the following: Figure 3 The structure shown. (As illustrated) Figure 3 As shown, the insulating layer 320 formed of insulating material has been polished, exposing the first pad 311 and the second pad 301. The through-hole 330 on the insulating layer 320 leads directly to the temporary carrier board at the first location.

[0036] Copper seed layer sputtering was performed using RDL technology to obtain, as shown in the figure. Figure 4 The structure shown. (As illustrated) Figure 4 As shown, the seed layer 340 is disposed above the insulating layer 320. The inner wall of the perforation formed after laser drilling also has a seed layer structure.

[0037] Photoresist is spin-coated over the seed layer to define fan-out circuitry. Copper is then electroplated to fill the vias, resulting in the desired structure. Figure 5 The structure shown. (As illustrated) Figure 5 As shown, the electroplated layer 360 fills the areas not covered by the photoresist 350. The seed layer is on the micrometer scale; for easier identification of the diagram, as shown... Figure 5 The seed layer on the inner wall of the perforation shown in the subsequent figures is not shown. The thickness ratio of the seed layer to the electroplated layer is for illustrative purposes only and does not represent the actual dimensional relationship.

[0038] Remove the photoresist and etch away the unwanted seed layer to obtain... Figure 6 The structure shown. (As illustrated) Figure 6 As shown, a seed layer and an electroplating layer are sequentially disposed above each second pad 301.

[0039] The LED chip is flip-chip bonded onto the driver IC and electrically connected via soldering or bonding to achieve the desired result. Figure 7 The structure shown.

[0040] Silicone molding is performed to form planar or curved optical structures that meet the light emission angle requirements, thereby protecting the LED chip and driver chip. Specifically, transparent silicone planes or microlenses can be molded to obtain... Figure 8The structure shown.

[0041] Laser or thermal release removes the temporary carrier plate, exposing the first location, resulting in... Figure 9 The structure is shown. Then, UBM (Under Bump Metallization) and interconnect bumps are formed at the first location and diced to obtain the target package structure in die form, as shown. Figure 1 The structure shown.

[0042] like Figure 10 As shown, another embodiment of this disclosure provides a method for manufacturing an LED driver encapsulation structure, including the following steps: Step S201: Provide a driver chip and thin the bottom surface of the driver chip. For example... Figure 11 As shown, the active surface of the driver chip 210 is its upper surface, on which multiple first pads 111 are provided. These first pads are the input / output ports of the driver chip. A second pad 201 is also provided on the active surface of the driver chip for connecting to the LED chip. Before the thinning process, a protective layer 260 needs to be coated on the active surface of the driver chip to protect the first and second pads.

[0043] Step S202: At least one LED chip is mounted on top of the driver chip, and the LED chip and the driver chip are electrically connected by solder or copper-copper thermoforming. Then, the protective layer is removed to obtain the desired result. Figure 12 The structure is shown. The driver chip 210 is thinned to obtain the driver chip 110. Red light chip 121, green light chip 122 and blue light chip 123 are respectively soldered on the three pairs of second pads of the driver chip.

[0044] Step S203: Provide a temporary carrier board, and place the driver chip with the LED chip mounted on the temporary carrier board with its active side facing or away from the temporary carrier board. Then, coat the driver chip with photoresist to obtain the desired result. Figure 13 The structure is shown. The driver chip is positioned above the temporary carrier 280, and the photoresist 270 covers the driver chip.

[0045] After step S203, an opening is formed in the photoresist layer using a photolithography process to expose the first pad, resulting in the following: Figure 14 The structure shown. Then, through injection molding, the insulating layer 292 is formed.

[0046] Step S204: A redistribution layer 291 is formed above the insulating layer. The redistribution layer electrically connects the first pad of the driver chip to a first location on the upper surface of the temporary carrier board. During the formation of the redistribution layer, a process is first performed by sputtering... Figure 15The seed layer of the redistribution layer 291 shown is then patterned using photolithography, and the protective layer 270 is removed to form the encapsulating colloid 260, thus obtaining the desired result. Figure 16 The structure shown.

[0047] Step S205: Remove the temporary carrier board to expose the first location.

[0048] Step S206: A UBM and interconnect bumps are formed at the first location to obtain the package structure. The package structure is then cut to obtain the desired result. Figure 17 The grains shown.

[0049] The thinning process mentioned in step S201 can employ a combination of mechanical polishing and chemical mechanical polishing (CMP). First, a coarse polishing wheel is used to rapidly thin the silicon substrate of the driver chip from an initial 700-800 μm to approximately 150 μm. Then, a fine polishing wheel and CMP are used for fine thinning and surface planarization, ultimately controlling the thickness deviation within ±5 μm. During the thinning process, the coated protective layer 260 can be a temporary bonding adhesive or a photothermal conversion release layer, with a thickness of 5-20 μm, effectively preventing polishing debris from contaminating the pads. After thinning, the protective layer can be removed by heating or laser irradiation, followed by cleaning and drying.

[0050] The temporary carrier 280 used in step S203 can be a glass carrier, a silicon carrier, or a metal carrier, preferably a glass carrier with a coefficient of thermal expansion similar to that of the driver chip. The temporary carrier and the driver chip are bonded together with temporary bonding adhesive. This adhesive has high adhesion at room temperature, but its adhesion decreases sharply when heated to above 150°C or irradiated with ultraviolet light, facilitating subsequent debonding. The photoresist 270 is typically coated with a thickness of 5μm to 30μm. After pre-baking, exposure, post-baking, and development, an opening is formed. The size of the opening should be 2μm to 5μm larger than the first pad to ensure sufficient metal filling during subsequent electroplating.

[0051] In step S204, when forming the redistribution layer 291, the sputtered seed layer is typically a titanium / copper bilayer structure, with the titanium layer serving as both an adhesion layer and a barrier layer. During photolithography patterning, a positive photoresist is used, and after development, a reverse pattern of the redistribution lines is formed. Electroplating can be performed using a copper sulfate-based plating solution. After photoresist removal, wet etching is used to remove the exposed seed layer, leaving only the electroplated copper portion.

[0052] The ball-mounting process in step S206 can be performed using a ball-mounting machine or by printing solder paste followed by reflow soldering. For example... Figure 18 The packaging structure shown is as follows Figure 16 A top view of the packaging structure shown. (See attached image.) Figure 19 What is shown is as follows Figure 18The illustrated package structure shows a single die structure, where the number of first pads 111 is four. This is for illustrative purposes only; in practical applications, the number of first pads is typically between six and twenty. This disclosure does not limit the number of first pads and can be flexibly adjusted according to the design of the driver chip. Figure 20 As shown, there can be six first pads 112, which are the pads for pins VCC, GND, DIN, DOUT, VLED_R, and VLED_GB, respectively. The copper vias 1121 on the first pads are obtained by laser perforation of the insulating material followed by copper plating and filling. These copper vias 1121 are located above the insulating layer 320.

[0053] In practical applications, a copper heat sink can be placed below the driver chip for heat dissipation and mechanical support.

[0054] The fabrication method of this disclosure utilizes a temporary carrier board and a redistribution layer to bring out the pads of the driver chip. After removing the temporary carrier board, the input / output ports of the package structure can be brought out directly by placing balls at the first position, without the need for TSVs or bonding wires. This simplifies the process flow, reduces manufacturing costs, and enables the production of ultra-thin lamp driver packaged devices.

[0055] When at least one LED chip is mounted on top of the driver chip in step S202, at least one LED chip can be mounted on top of the driver chip by flip-chip bonding or wire bonding.

[0056] The two mainstream chip mounting processes, flip-chip and wire bonding, can be selected as needed, allowing for flexible choice based on cost and performance requirements, thus improving the applicability of the method.

[0057] When forming the redistribution layer in step S204, the redistribution layer can be formed by sputtering, photolithography, electroplating and etching processes.

[0058] When forming the redistribution layer, standard semiconductor metal wiring processes can be used, such as sputtering a seed layer, photolithography to pattern the seed layer, electroplating to thicken the patterned seed layer, and etching to remove excess seed layer. This allows for the production of high-precision, fine-width / spacing redistribution conductors, ensuring the reliability and consistency of electrical connections.

[0059] Before forming the redistribution layer, an insulating layer is formed along the sidewall of the driver chip between the first pad of the driver chip and the temporary carrier board, and the insulating layer is polished to expose the first pad.

[0060] Forming an insulating layer on the sidewall provides insulation support for subsequent rewiring layers, and the opening exposing the first pad ensures the reliability of the electrical connection.

[0061] After the redistribution layer is formed, an encapsulating colloid is formed above and to the side of the driver chip to encapsulate at least one LED chip and the driver chip.

[0062] By forming an encapsulating colloid, the LED chip and driver chip can be completely encapsulated, thereby improving the environmental resistance and mechanical strength of the encapsulated device, preventing the chip from being contaminated or physically damaged, and extending its service life.

[0063] In this embodiment of the disclosure, the molded silicone lens can also be, for example, Figure 21 The lens shown has a hemispherical convex surface, or a lens with a saddle-shaped convex surface as shown in 22.

[0064] According to the LED driver encapsulation packaging structure and manufacturing method provided in the embodiments of this disclosure, by extending the redistribution wire along the sidewall of the driver chip to a first position flush with the bottom surface, and setting interconnect bumps at that position to bring out the input / output ports of the packaging structure, the problem of excessive packaging thickness and volume caused by using bonding wires is avoided, as well as the high cost problem caused by using TSV through-hole technology, thereby reducing the thickness of the LED driver encapsulation packaging structure and reducing its cost.

[0065] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A packaging structure for LED driver assembly, characterized in that, include: A driver chip has an active surface and a bottom surface opposite to the active surface, and the active surface is provided with a plurality of first pads; At least one LED chip is mounted on the driver chip and electrically connected to the driver chip; A redistribution layer is disposed on the active side of the driver chip. The redistribution layer includes multiple redistribution wires. One end of each redistribution wire is electrically connected to the corresponding first pad, and the other end extends along the sidewall of the driver chip to a first position that is level with the bottom surface of the driver chip. Multiple interconnecting bumps are respectively disposed at the first position and electrically connected to the other end of the redistribution wire.

2. The packaging structure according to claim 1, characterized in that, The LED chip includes a flip-chip LED, which is mounted on the active surface of the driver chip using solder or copper-to-copper bonding.

3. The packaging structure according to claim 1, characterized in that, The redistribution layer includes at least one metal layer. The redistribution layer completes the chip-scale package (CSP) of the LED driver using a fan-out RDL process. An insulating layer is provided between the redistribution layer and the driver chip. The insulating layer includes epoxy resin, silicone resin, polyimide, BCB, polyimide, or benzocyclobutene.

4. The packaging structure according to claim 1, characterized in that, The at least one LED chip includes a red light chip, a green light chip, and a blue light chip; or, the at least one LED chip includes a red light chip, a green light chip, a blue light chip, and an X chip, wherein the X chip includes a cyan chip, a yellow chip, or another fourth primary color chip; or, the at least one LED chip includes multiple Micro-LEDs arranged in an array after being connected in series.

5. The packaging structure according to claim 1, characterized in that, It also includes an encapsulating colloid that covers the LED chip and at least a portion of the driver chip, wherein the plurality of interconnect bumps are exposed from the encapsulating colloid; wherein the interconnect bumps include copper layers, copper pads, solder pads or solder balls.

6. A method for manufacturing a package structure for LED driver encapsulation, characterized in that, Includes the following steps: A driver chip is provided, and the bottom surface of the driver chip is thinned. The active surface of the driver chip is provided with a plurality of first pads. A temporary carrier board is provided, and the driver chip is placed on the temporary carrier board with its active surface facing or away from the temporary carrier board; A redistribution layer is formed, wherein the redistribution layer electrically connects the first pad of the driver chip to a first position on the upper surface of the temporary carrier board; At least one LED chip is mounted on top of the driver chip, and the LED chip and the driver chip are electrically connected by solder or copper-copper thermoforming bonding. Silicone molding is performed to form a planar optical structure or a curved optical structure that meets the light emission angle requirements, in order to protect the LED chip and the driver chip. Remove the temporary carrier plate to expose the first location; Interconnect bumps are formed at the first location and then cut to obtain the package structure in the form of dies.

7. The manufacturing method according to claim 6, characterized in that, Before forming the redistribution layer, the method further includes: An insulating material is molded over the temporary carrier board and the driver chip, and the insulating material is ground to expose the first pad. The insulating material is then laser-perforated to the first position.

8. A method for manufacturing an LED driver encapsulation structure, characterized in that, Includes the following steps: A driver chip is provided, and the bottom surface of the driver chip is thinned. The active surface of the driver chip is provided with a plurality of first pads. At least one LED chip is mounted on top of the driver chip, and the LED chip and the driver chip are electrically connected by solder or copper-copper thermoforming bonding. A temporary carrier board is provided, and the driver chip with the LED chip mounted on it is placed on the temporary carrier board with its active surface facing or away from the temporary carrier board. A redistribution layer is formed, wherein the redistribution layer electrically connects the first pad of the driver chip to a first position on the upper surface of the temporary carrier board; Remove the temporary carrier plate to expose the first location; Interconnect bumps are formed at the first location to obtain the package structure.

9. The manufacturing method according to claim 8, characterized in that, Forming a redistribution layer includes forming the redistribution layer through sputtering, photolithography, electroplating, and etching processes.

10. The manufacturing method according to claim 8, characterized in that, Before forming the redistribution layer, the method further includes: An insulating layer is formed along the sidewall of the driver chip between the first pad of the driver chip and the temporary carrier board, and the insulating layer is polished to expose the first pad.

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