Full-chip co-planar micro-led vehicle lamp packaging structure and preparation method thereof

Abstract

This invention discloses a fully coplanar MicroLED automotive lamp packaging structure and its fabrication method, belonging to the field of semiconductor packaging technology. The packaging structure includes a packaging substrate layer, within which multiple types of chips, multiple redistribution layers, silicon bridges, signal vias, thermal vias, and a heat dissipation substrate are integrated. The active surfaces of the multiple types of chips are arranged coplanarly, while the passive surfaces are exposed in the packaging substrate layer. The silicon bridge is embedded between adjacent layers of the multiple redistribution layers and electrically connected to both adjacent layers. The top of the thermal via is connected to the heat dissipation pads of the active surfaces of the multiple types of chips, and the bottom of the thermal via is connected to the heat dissipation substrate. The top of the signal via is electrically connected to the multiple redistribution layers, and the bottom of the signal via passes through the packaging substrate layer and is exposed at the bottom of the packaging substrate layer. This invention achieves high integration, high-speed transmission, efficient heat dissipation, and high automotive reliability in MicroLED automotive lamp packaging.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and in particular to a fully coplanar MicroLED automotive lamp packaging structure and its fabrication method. Background Technology

[0002] With the development of intelligent vehicle technology, adaptive high beam (ADB) and projection lighting have become key technologies for improving driving safety and interactive experience. MicroLED, due to its high brightness, high contrast, and fast response characteristics, has become an ideal choice for next-generation automotive lighting. Currently, MicroLED modules mainly use discrete packaging. The MicroLED chip is bonded to a CMOS chip to form the light source chip, while the driver chip, power management chip, and image processing chip are packaged separately and connected to the light source chip via a PCB.

[0003] The existing technology has the following drawbacks: the CMOS chip is located below the MicroLED, and heat needs to be conducted through the CMOS, resulting in high thermal resistance; the bonding layer is a permanent connection, and the CMOS or MicroLED cannot be replaced separately, making upgrades impossible; any defect in any layer can render the entire chip unusable, resulting in significant yield loss. Long PCB traces increase signal delay and interconnection delay; multiple modules occupy a lot of space and are bulky; long traces cause electromagnetic interference.

[0004] This industry is rapidly evolving and urgently needs a MicroLED automotive lighting packaging structure that features thinner devices, lower thermal resistance, shorter interconnect latency, and easier chip updates. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in order to solve at least one technical problem existing in the prior art, the present invention provides a fully coplanar MicroLED automotive lamp packaging structure and its preparation method.

[0006] The technical solution adopted by this invention to solve its technical problem is: The present invention provides a fully coplanar MicroLED automotive lamp packaging structure, characterized in that it includes a packaging substrate layer, wherein multiple types of chips, multiple redistribution layers, silicon bridges, signal vias, thermal vias and a heat dissipation substrate are integrated within the packaging substrate layer; The active surfaces of the various types of chips are arranged in a coplanar manner, the passive surfaces of the various types of chips are exposed on the packaging substrate layer, and the active surfaces of the various types of chips are electrically connected to the uppermost layer of the multilayer redistribution layer; the silicon bridge is embedded between two adjacent layers of the multilayer redistribution layer and is electrically connected to both adjacent layers. The thermal via penetrates multiple redistribution layers and is electrically isolated from each other. The top of the thermal via is connected to the heat dissipation pads of the active surface of the multi-chip, and the bottom of the thermal via is connected to the heat dissipation substrate. The top of the signal via is electrically connected to the multilayer redistribution layer, and the bottom of the signal via passes through the packaging substrate layer and is exposed at the bottom of the packaging substrate layer. This achieves multi-chip coplanar integration and complete separation of thermal and electrical paths, combining high integration, efficient heat dissipation, and high-speed signal transmission, thereby improving the reliability and packaging stability of automotive lights.

[0007] Furthermore, the multilayer redistribution layer includes a bump layer, a control layer, a signal layer, and a power layer arranged sequentially from top to bottom; The bump layer is used for electrical connection with various types of chips; the control layer is used for transmitting image control signals for the MicroLED automotive lights; the signal layer is used for transmitting drive signals for the MicroLED automotive lights; and the power layer is used for transmitting power signals. By employing a layered layout of bump, control, signal, and power layers, independent transmission of signals, drives, and power is achieved, reducing crosstalk and improving electrical performance.

[0008] Furthermore, the various types of chips include MicroLED light-emitting chips, driver chips, power management chips, communication interface chips, and image processing chips; The driving chip includes a row driving chip and a column driving chip. The row driving chip is connected to the row electrode of the MicroLED light-emitting chip through a signal layer, and the column driving chip is connected to the column electrode of the MicroLED light-emitting chip through a signal layer. The power management chip is connected to the driver chip via a power layer, and the image processing chip is connected to the driver chip via a control layer. The integration of the light-emitting, driver, power, communication, and image processing chips simplifies the system structure and improves the vehicle's lighting response speed and control accuracy.

[0009] Furthermore, both the top and bottom surfaces of the silicon bridge are provided with microbumps. The top surface of the silicon bridge is electrically connected to the bump layer through the microbumps, and the bottom surface of the silicon bridge is electrically connected to the control layer through the microbumps. The image processing chip is interconnected with the driver chip through the bump layer, the silicon bridge, and the control layer, achieving high-bandwidth point-to-point interconnection between the image processing chip and the driver chip. The silicon bridge enables high-bandwidth point-to-point interconnection between the image processing chip and the driver chip, improving image transmission rate and meeting the requirements of high-speed vehicle control.

[0010] Furthermore, a silver paste layer is provided between the bottom layer of the multilayer redistribution layer and the heat dissipation substrate, and the bottom of the thermally conductive via is interconnected with the heat dissipation substrate through the silver paste layer.

[0011] Furthermore, the encapsulation substrate layer is an epoxy resin molding compound layer. It features high structural strength, good heat resistance, and is suitable for harsh automotive environments.

[0012] Furthermore, the heat dissipation substrate is made of copper-molybdenum-copper composite material or aluminum silicon carbide. A microchannel cooling structure is provided inside the heat dissipation substrate, and the bottom of the thermally conductive vias extends to the wall surface of the microchannel cooling structure. The high thermal conductivity heat dissipation substrate, combined with the microchannel cooling structure, enables rapid heat dissipation from the chip, significantly reducing junction temperature and improving luminous efficiency and lifespan.

[0013] On the other hand, the present invention provides a method for fabricating a fully coplanar MicroLED automotive lamp packaging structure, comprising: S1. Prepare a temporary carrier board, fabricate multiple redistribution layers on the temporary carrier board, and embed silicon bridges between the bump layer and the control layer of the multiple redistribution layers. S2. A through-hole is formed in the multilayer redistribution layer, the top of which is exposed on the surface of the bump layer. S3. The various types of chips are mounted on the bump layer according to their functional partitions, so that the heat dissipation pads of the MicroLED light-emitting chips are connected to the top of the heat-conducting through holes. S4. Mold the package structure after chip mounting to form the first package substrate layer; S5. Remove the temporary carrier plate to expose the bottom surface of the multilayer redistribution layer and the bottom of the heat-conducting vias; S6. A heat dissipation substrate is attached to the bottom surface of the multilayer redistribution layer, so that the bottom of the heat-conducting through hole is connected to the heat dissipation substrate. S7. After mounting the heat dissipation substrate, the encapsulation structure is encapsulated to form a second encapsulation substrate layer. Signal vias are fabricated within the second encapsulation substrate layer, with the top of the signal vias electrically connected to the multilayer redistribution layer and the bottom of the signal vias exposed at the bottom of the second encapsulation substrate layer. BGA electrical pads are formed at the bottom of the second encapsulation substrate layer. This achieves coplanar encapsulation, silicon bridge embedding, and simultaneous fabrication of thermoelectric vias, exhibiting strong process compatibility and suitability for panel-level mass production.

[0014] Furthermore, in step S2, the thermally conductive vias are formed by laser drilling, and then filled with electroplated copper. Before filling, an insulating layer is formed on the inner wall of the vias by chemical vapor deposition. This ensures that the thermally conductive vias have high thermal conductivity and are electrically isolated from the redistribution layer, achieving both heat dissipation and insulation.

[0015] Furthermore, the encapsulation process in step S4 employs a thin-film assisted encapsulation process, ensuring that the passive surface of the MicroLED light-emitting chip is not covered by molding compound during encapsulation. Precise control of the encapsulation height guarantees that the passive surface of the MicroLED is exposed to light, resulting in a smooth encapsulation surface and good structural consistency.

[0016] The beneficial effects of this invention are: This invention achieves extremely high integration and reliability through a collaborative design that combines full-chip coplanar integration, layered redistribution, high-bandwidth silicon bridge interconnection, and complete separation of thermal vias. The multi-chip coplanar layout, combined with the layered redistribution layer, shortens interconnection distances, reduces signal crosstalk, and improves driving and image control speed. The silicon bridge enables high-bandwidth point-to-point interconnection, while also accommodating the UCIe standardized interface, resulting in enhanced system compatibility and real-time performance. Independent isolation between thermal vias and signal vias forms a direct, efficient heat dissipation path, significantly reducing junction temperature and improving LED lifespan and luminous efficiency. The overall integrated packaging structure is compact, the process is mass-producible, effectively reducing the size of the automotive lamp and improving system stability and resistance to temperature variations. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] Figure 1 This is an overall cross-sectional view of the MicroLED automotive lamp packaging structure according to Embodiment 1 of the present invention; Figure 2 This is an overall top view of the MicroLED automotive lamp packaging structure according to Embodiment 1 of the present invention; Figure 3 This is a cross-sectional view of the heat-conducting through hole in Embodiment 1 of the present invention; Figure 4 This is a top view of the heat-conducting through-hole in Embodiment 1 of the present invention; Figure 5 This is a cross-sectional view of the signal through hole in Embodiment 1 of the present invention.

[0019] In the diagram: 1. Encapsulation substrate layer; 101. First encapsulation substrate layer; 102. Second encapsulation substrate layer; 2. MicroLED light-emitting chip; 21. Thermal pad; 3. Power management chip; 4. Image processing chip; 5. Communication interface chip; 6. Driver chip; 61. Row driver chip; 62. Column driver chip; 7. Multilayer redistribution layer; 71. Bump layer; 72. Control layer; 73. Signal layer; 74. Power layer; 8. Silicon bridge; 9. Thermal via; 10. Heat dissipation substrate; 11. Signal via; 12. Silver paste layer; 13. BGA electrical pad; 14. BGA thermal pad. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0021] Example 1: like Figure 1As shown, this embodiment provides a fully coplanar MicroLED automotive lamp packaging structure, including a packaging substrate layer 1, which integrates multiple types of chips, a multilayer redistribution layer 7, a silicon bridge 8, signal vias 11, thermal vias 9, and a heat dissipation substrate 10.

[0022] The encapsulation substrate layer 1 is made of panel-grade epoxy resin molding compound with a glass transition temperature Tg ≥ 180℃ and its size can be adjusted according to the chip array scale.

[0023] like Figure 2 As shown, multiple types of chips are embedded in the encapsulation substrate layer 1, including a MicroLED light-emitting chip 2, a driver chip, a power management chip 3, a communication interface chip 5, and an image processing chip 4. The active surfaces of all chips face the same direction and are made coplanar through grinding and polishing, with a coplanarity of ≤5μm, realizing the miniaturization, thinning, and high integration design of the automotive lamp.

[0024] Specifically, the MicroLED light-emitting chip 2 adopts a common cathode design and uses yellow phosphor to achieve white light output. The passive surface of the MicroLED light-emitting chip 2 is exposed on the encapsulation substrate layer 1 so that the LED light can be emitted to achieve illumination and projection. The driving chips include a row driving chip 61 and a column driving chip 62. The row driving chip 61 is connected to the row electrode of the MicroLED light-emitting chip 2 through a signal layer 73 (one of the multi-layer redistribution layers), and the column driving chip 62 is connected to the column electrode of the MicroLED light-emitting chip 2 through a signal layer 73. The power management chip 3 is connected to the driving chips through a power layer 74 and supports multiple voltage outputs. The image processing chip 4 is connected to the driving chip through a control layer 72, and the spacing between the image processing chip 4 and the MicroLED light-emitting chip 2 is 300~500μm. The communication interface chip 5 integrates CAN FD and automotive Ethernet PHY.

[0025] The multilayer redistribution layer 7 is fabricated using a semi-additive method and includes, from top to bottom, a bump layer 71, a control layer 72, a signal layer 73, and a power layer 74. Each layer is isolated by a silicon dioxide dielectric layer and filled with copper. The bump layer 71 has a linewidth of 30-40 μm and a thickness of 6-8 μm, and is used for electrical connections with various chips. The control layer 72 has a linewidth and spacing of 4 μm and a thickness of 2 μm, arranged in a bus topology, connecting the image processing chip 4 to each driver chip, and is used to transmit image control signals for the MicroLED automotive lights. The signal layer 73 has a linewidth and spacing of 8 μm and a thickness of 3 μm, arranged in a grid pattern, and is used to transmit drive signals for the MicroLED automotive lights, enabling row / column drive signal routing. The power layer 74 has a linewidth and spacing of 15 μm and a thickness of 4-5 μm, arranged radially, and is used to transmit power signals, connecting the power management chip 3 to each driver chip. This design reduces interlayer cross-interference and shortens the interconnection distance between chips.

[0026] It should be noted that the upper surface of the bump layer 71 is provided with microbumps with a spacing of 45~55μm. These microbumps represent the standardized UCIe interface, which conforms to the physical layer requirements of the Universal Chip Interconnect (UCIe) protocol. The UCIe interface includes: power pins, supporting multiple voltage rails of 3.3V, 5V, and 12V, with a current capacity ≥1A / pin; data pins, a 16-bit parallel data bus or 4 pairs of differential signals; control pins, clock (CLK), chip select (CS), reset (RST), and interrupt (INT); and hot-plug detection pins, which identify chip replacement events and trigger power timing management. The active surfaces of all chips are electrically connected to the top layer of the multilayer redistribution layer 7 (i.e., bump layer 71) through the microbumps.

[0027] The silicon bridge 8 is embedded between the bump layer 71 and the control layer 72 of the multilayer redistribution layer 7. Both the top and bottom surfaces of the silicon bridge 8 have microbumps with a spacing of 25-35 μm, used for high-bandwidth point-to-point connections between the image processing chip 4 and the driver chip. Specifically, the top surface of the silicon bridge 8 is electrically connected to the under-bump metal layer (UBM) on the surface of the bump layer 71 through microbumps, and the bottom surface of the silicon bridge 8 is electrically connected to the control layer 72 through microbumps. The image processing chip 4 achieves high-bandwidth interconnection with the driver chip through the bump layer 71, the silicon bridge 8, and the control layer 72. The silicon bridge 8 is fixed to the bump layer 71 and the control layer 72 by thermocompression bonding, and the gaps are filled with bottom filler to bond with the surrounding silicon dioxide dielectric layer. The silicon bridge 8 uses customized copper wiring to maximize bandwidth density and does not have a standard interface.

[0028] MicroLED chip 2 is a flip chip. In addition to signal bumps, its active surface is also provided with metal pads for heat dissipation. These pads are not connected to the active circuit inside the chip and only serve as a heat conduction interface.

[0029] The thermal via 9 is filled with high-purity copper and has a diameter of 80-120 μm. It penetrates the multi-layer redistribution layer 7 and is electrically isolated from it. The top of the via 9 is connected to the heat dissipation pad 21 of the active surface of various chips (mainly MicroLED light-emitting chips 2), and the bottom is connected to the heat dissipation substrate 10 via a silver paste layer 12. Heat from the chip is transferred to the heat dissipation substrate 10 through the heat dissipation pad 21 on the active surface and the thermal via 9. A BGA heat dissipation pad 14 is formed on the bottom surface of the heat dissipation substrate 10. This achieves high-density heat dissipation within a very small package size, effectively solving the problem of heat accumulation in MicroLED arrays.

[0030] The heat dissipation substrate 10 is made of copper-molybdenum-copper composite material or aluminum silicon carbide. The heat dissipation substrate 10 has a microchannel cooling structure inside, and the bottom of the heat conduction hole 9 extends to connect to the wall of the microchannel cooling structure.

[0031] The top of the signal via 11 is electrically connected to the multilayer redistribution layer 7 (e.g., to pads connected to the power layer 74 and signal layer 73). The bottom of the signal via 11 passes through the package substrate layer 1 and is exposed at the bottom of the package substrate layer 1, where a BGA electrical pad 13 is formed. Specifically, an insulating via is formed within the package substrate layer 1, and the signal via 11 is disposed within the insulating via. An insulating dielectric layer (such as silicon dioxide) is provided between the outer wall of the signal via 11 and the inner wall of the insulating via. This enables complete transmission of electrical signals from the active surface of the chip to the bottom surface of the package substrate layer 1.

[0032] It should be noted that the thermal via 9 and the signal via 11 are completely independent in structure and function. The thermal via 9 is dedicated to heat dissipation, while the signal via 11 is dedicated to electrical interconnection. The two are arranged in parallel in the package structure and do not interfere with each other.

[0033] It is worth mentioning that the epoxy resin molding compound layer uses laser-sensitive epoxy resin with a decomposition temperature of 180~220℃. When the chip needs to be replaced, it can be precisely removed by selective laser ablation, enabling the chip to be upgraded and replaced.

[0034] The working principle of this embodiment is as follows: The MicroLED light-emitting chip 2, driver chip, and other chips embedded in the encapsulation substrate layer 1 are made coplanar through grinding and polishing. These chips are electrically connected to the multilayer redistribution layer 7 via UCIe standard microbumps on the bump layer 71. The image processing chip 4 is interconnected with the driver chip via a silicon bridge 8 to achieve high bandwidth. The driver chip drives the MicroLED light-emitting chip 2. The power management chip 3 and the communication interface chip 5 provide power support and communication functions, respectively. The heat from the chips is transferred to the heat dissipation substrate 10 with a microchannel cooling structure through the active surface heat dissipation pad 21 and the high-purity copper filled thermal vias 9. The electrical signals are transmitted to the BGA pads on the bottom surface of the encapsulation substrate layer 1 through the multilayer redistribution layer 7 and the signal vias 11. The heat conduction and signal transmission structures are independent and parallel, and do not interfere with each other.

[0035] The coplanar arrangement of multiple active surfaces provides a structural foundation for the orderly wiring and micro-bump bonding of the multi-layer redistribution layer 7. The differentiated topology of the redistribution layer enables crosstalk-free transmission of signals, power, and control paths, with the two supporting each other. The UCIe standard interface of the bump layer 71 enables universal interconnection, and the silicon bridges 8 embedded between the redistribution layers form a high-bandwidth point-to-point channel, taking into account both system compatibility and the high-speed control requirements of automotive applications. The MicroLED light-emitting chip adopts a flip-chip structure and is equipped with a dedicated heat dissipation pad 21, which forms a continuous and efficient heat dissipation path with the high-purity copper thermal vias 9 penetrating the redistribution layer and the heat dissipation substrate 10 with built-in microfluidics. At the same time, the thermal vias 9 and signal vias 11 are independently arranged and electrically isolated, achieving complete separation of thermal and electrical paths. This not only greatly improves heat dissipation capacity but also avoids heat interference with high-speed signals, ensuring signal integrity and operational reliability. The encapsulation substrate, composed of panel-grade epoxy resin molding compound, provides a stable load-bearing structure for multi-chip coplanar integration, redistribution layer stacking, silicon bridge embedding, and via layout. It can withstand dimensional deformation under high and low temperature environments in the automotive industry, maintain chip coplanarity and the reliability of each interconnect structure, and enable the overall packaging to achieve synergistic improvement in integration, heat dissipation performance, and adaptability to the automotive environment.

[0036] Example 2: This embodiment provides a method for fabricating a fully coplanar MicroLED automotive lamp packaging structure as described in Embodiment 1, including: S1. Prepare a temporary carrier board (glass or silicon wafer), coat a temporary bonding layer on the temporary carrier board and fabricate a multilayer redistribution layer 7 using a semi-additive method, and embed a silicon bridge 8 between the bump layer 71 and the control layer 72 of the multilayer redistribution layer 7.

[0037] Specifically, a power layer 74, a signal layer 73, and a control layer 72 are first fabricated on a temporary carrier board. A silicon dioxide dielectric layer is formed between adjacent layers of the power layer 74, signal layer 73, and control layer 72, and on the upper surface of the control layer 72. A groove (i.e., the silicon bridge setting area) is cut in the silicon dioxide dielectric layer on the upper surface of the control layer 72 corresponding to the mounting position of the silicon bridge 8, so that the bottom of the groove exposes the connection pad of the control layer 72. The silicon bridge 8 is then embedded in the groove (i.e., the silicon bridge setting area), and the micro-bumps on the bottom surface of the silicon bridge 8 are electrically connected to the connection pads of the control layer 72 through thermo-press bonding. Then, a bump layer 71 is fabricated on the silicon dioxide dielectric layer and the top surface of the silicon bridge 8, so that the bottom pad of the bump layer 71 is electrically connected to the micro-bumps on the top surface of the silicon bridge 8.

[0038] Specifically, a chip mounting area is reserved on the upper surface of the bump layer 71, and a standardized UCIe interface (composed of microbumps) is fabricated.

[0039] S2. Within the multilayer redistribution layer 7, at the location corresponding to the heat dissipation pad 21 of the MicroLED light-emitting chip 2, a thermally conductive via 9 is formed through the power layer 74, signal layer 73, control layer 72, bump layer 71, and each silicon dioxide dielectric layer using a laser drilling process. Silicon dioxide is deposited on the inner wall of the via (chemical vapor deposition) to form an insulating layer, thereby creating electrical isolation between the thermally conductive via 9 and the metal lines in the multilayer redistribution layer 7. Subsequently, the thermally conductive via 9 is filled with electroplated copper to form a continuous heat conduction path. The top of the thermally conductive via 9 extends and is exposed on the surface of the bump layer 71, allowing for direct contact and thermal coupling with the heat dissipation pad 21 of the active surface of the MicroLED light-emitting chip 2.

[0040] S3. Multiple types of chips are mounted on the bump layer 71 according to functional partitions, ensuring precise alignment between the microbumps on the active side of each chip and the standardized UCIe interface on the surface of the bump layer 71. Simultaneously, the heat dissipation pads 21 on the active side of the MicroLED chip 2 are made into corresponding contact with the top of the thermal vias 9. A thermosetting bonding process is used to simultaneously achieve electrical connection between the chip microbumps and the bump layer 71, as well as thermal connection between the heat dissipation pads 21 and the thermal vias 9.

[0041] S4. The package structure after chip mounting is encapsulated to form the first encapsulation substrate layer 101, exposing the passive surface of the MicroLED light-emitting chip 2 from the upper surface of the first encapsulation substrate layer 101. A thin-film assisted encapsulation process is used to ensure that the passive surface of the MicroLED light-emitting chip 2 is not covered by molding compound during the encapsulation process.

[0042] Specifically, an epoxy resin molding compound with a high glass transition temperature is used for compression encapsulation to form a first encapsulation substrate layer 101 that encapsulates each chip and the redistribution layer area. During the molding process, the molding height is controlled, and a thin-film assisted molding process is used to make the passive surface of the MicroLED light-emitting chip 2 flush with the upper surface of the first encapsulation substrate layer 101. Ultimately, the passive surface of the MicroLED light-emitting chip 2 is exposed from the upper surface of the first encapsulation substrate layer 101 to ensure that the light emission path is unobstructed and to meet the requirements for lighting and projection.

[0043] S5. The temporary carrier board is removed by laser debonding or mechanical grinding and thinning process. The bottom surface of the package after removal is flattened to expose the bottom surface of the multilayer redistribution layer 7 (i.e. the bottom surface of the bottom power layer 74) and the bottom of the thermal via 9, so as to provide a flat and reliable bonding interface for subsequent bonding with the heat dissipation substrate 10.

[0044] S6. A heat dissipation substrate 10 is attached to the bottom surface of the multilayer redistribution layer 7, so that the bottom of the heat conduction hole 9 is connected to the heat dissipation substrate 10. Specifically, a silver paste layer 12 is first coated to form on the bottom surface of the exposed multilayer redistribution layer 7, and then the heat dissipation substrate 10 is attached. The silver paste layer 12 is cured by hot pressing and sintering to form a highly efficient thermal interface, so that the bottom of the heat conduction hole 9 is tightly thermally connected to the heat dissipation substrate 10 through the silver paste layer 12.

[0045] S7. The package structure after mounting the heat sink substrate 10 is encapsulated to form a second package substrate layer 102 encapsulating the side of the heat sink substrate 10. Insulating vias are formed within the second package substrate layer 102 (insulation is achieved by depositing silicon dioxide or other insulating dielectric layers on the inner wall). Signal vias 11 are formed within the insulating vias, with the top of the signal vias 11 electrically connected to the multilayer redistribution layer 7, and the bottom of the signal vias 11 exposed at the bottom of the second package substrate layer 102. BGA electrical pads 13 are formed at the bottom of the second package substrate layer 102. Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A fully coplanar MicroLED automotive lamp packaging structure, characterized in that, It includes a packaging substrate layer (1), which integrates multiple types of chips, a multilayer redistribution layer (7), a silicon bridge (8), signal vias (11), thermal vias (9), and a heat dissipation substrate (10). The active surfaces of the various types of chips are arranged in a coplanar manner, and the passive surfaces of the various types of chips are exposed on the packaging substrate layer (1). The active surfaces of the various types of chips are electrically connected to the uppermost layer of the multilayer redistribution layer (7). The silicon bridge (8) is embedded between two adjacent layers of the multilayer redistribution layer (7) and is electrically connected to both adjacent layers. The thermal via (9) penetrates the multilayer redistribution layer (7) and is electrically isolated from the multilayer redistribution layer (7). The top of the thermal via (9) is connected to the heat dissipation pad (21) of the active surface of the multi-type chip, and the bottom of the thermal via (9) is connected to the heat dissipation substrate (10). The top of the signal via (11) is electrically connected to the multilayer redistribution layer (7), and the bottom of the signal via (11) passes through the encapsulation substrate layer (1) and is exposed at the bottom of the encapsulation substrate layer (1).

2. The all-chip coplanar MicroLED automotive lamp packaging structure according to claim 1, characterized in that, The multi-layer redistribution layer (7) includes a bump layer (71), a control layer (72), a signal layer (73), and a power layer (74) arranged sequentially from top to bottom. The bump layer (71) is used for electrical connection with multiple types of chips; the control layer (72) is used for transmitting image control signals of MicroLED vehicle lights; the signal layer (73) is used for transmitting drive signals of MicroLED vehicle lights; and the power layer (74) is used for transmitting power signals.

3. The all-chip coplanar MicroLED automotive lamp packaging structure according to claim 2, characterized in that, The various types of chips include MicroLED light-emitting chips (2), driver chips, power management chips (3), communication interface chips (5), and image processing chips (4). The driving chip includes a row driving chip (61) and a column driving chip (62). The row driving chip (61) is connected to the row electrode of the MicroLED light-emitting chip (2) through a signal layer (73), and the column driving chip (62) is connected to the column electrode of the MicroLED light-emitting chip (2) through a signal layer (73). The power management chip (3) is connected to the driver chip through the power layer (74), and the image processing chip (4) is connected to the driver chip through the control layer (72).

4. The all-chip coplanar MicroLED automotive lamp packaging structure according to claim 3, characterized in that, The top and bottom surfaces of the silicon bridge (8) are provided with microbumps. The top surface of the silicon bridge (8) is electrically connected to the bump layer (71) through the microbumps, and the bottom surface of the silicon bridge (8) is electrically connected to the control layer (72) through the microbumps. The image processing chip (4) is interconnected with the driver chip with high bandwidth through the bump layer (71), the silicon bridge (8) and the control layer (72).

5. The all-chip coplanar MicroLED automotive lamp packaging structure according to claim 1, characterized in that, A silver paste layer (12) is provided between the bottom layer of the multilayer redistribution layer (7) and the heat dissipation substrate (10), and the bottom of the thermally conductive via (9) is interconnected with the heat dissipation substrate (10) through the silver paste layer (12).

6. The all-chip coplanar MicroLED automotive lamp packaging structure according to claim 1, characterized in that, The encapsulation substrate layer (1) is an epoxy resin molding compound layer.

7. The all-chip coplanar MicroLED automotive lamp packaging structure according to claim 1, characterized in that, The heat dissipation substrate (10) is made of copper-molybdenum-copper composite material or aluminum silicon carbide. The heat dissipation substrate (10) is provided with a microchannel cooling structure inside. The bottom of the heat-conducting through hole (9) is connected to the wall of the microchannel cooling structure.

8. A method for fabricating a fully coplanar MicroLED automotive lamp packaging structure as described in any one of claims 1 to 7, characterized in that, include: S1. Prepare a temporary carrier board, fabricate multiple redistribution layers (7) on the temporary carrier board, and embed a silicon bridge (8) between the bump layer (71) and the control layer (72) of the multiple redistribution layers (7). S2. A through-hole (9) is formed in the multilayer redistribution layer (7), the top of which is exposed on the surface of the bump layer (71). S3. The various types of chips are mounted on the bump layer (71) according to their functional partitions, so that the heat dissipation pad (21) of the MicroLED light-emitting chip (2) is connected to the top of the heat-conducting through hole (9); S4. The package structure after chip mounting is encapsulated to form the first package substrate layer (101). S5. Remove the temporary carrier plate to expose the bottom surface of the multilayer redistribution layer (7) and the bottom of the heat-conducting through-hole (9); S6. A heat dissipation substrate (10) is attached to the bottom surface of the multilayer redistribution layer (7) so that the bottom of the heat conduction through hole (9) is connected to the heat dissipation substrate (10). S7. After mounting the heat dissipation substrate (10), the packaging structure is encapsulated to form a second packaging substrate layer (102). Signal vias (11) are made in the second packaging substrate layer (102), so that the top of the signal vias (11) is electrically connected to the multilayer redistribution layer (7), the bottom of the signal vias (11) is exposed at the bottom of the second packaging substrate layer (102), and BGA electrical pads (13) are formed at the bottom of the second packaging substrate layer (102).

9. The preparation method according to claim 8, characterized in that, The heat-conducting through-hole (9) in step S2 is formed by laser drilling, and then the through-hole is filled with electroplated copper. Before filling, an insulating layer is formed on the inner wall of the through-hole by chemical vapor deposition.

10. The preparation method according to claim 8, characterized in that, The encapsulation process in step S4 uses a thin-film assisted encapsulation process to ensure that the passive surface of the MicroLED light-emitting chip (2) is not covered by the molding compound during the encapsulation process.

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