LED packaging device with metal support

Abstract

The utility model discloses an LED packaging device with a metal support. The LED packaging device comprises a first metal sheet, a second metal sheet, a flip chip and a fluorescent glue layer. A first groove is formed in the lower surface of the first metal sheet, a second groove opposite to the first groove is formed in the lower surface of the second metal sheet, and electroplated layers are arranged on the surfaces of the first metal sheet and the second metal sheet; the positive electrode of the flip chip is welded on the upper surface of the first metal sheet, and the negative electrode is welded on the upper surface of the second metal sheet; the fluorescent glue layer coats the outer layer of the flip chip, fills the gap between the first metal sheet and the second metal sheet, and fills the first groove and the second groove; the gaps between the flip chip and the first metal sheet and between the flip chip and the second metal sheet are filled with the fluorescent glue layer to form the insulating layer, and the mounting short-circuit rate is reduced to be smaller than or equal to 0.01%; in the aspect of heat dissipation performance, the junction temperature is reduced by 25-30 DEG C compared with that of a BT resin substrate, and the service life is prolonged by 50%; meanwhile, the steps of solder mask coating, secondary packaging and the like are omitted, and the production cost is reduced by 40%; and 0.6 * 0.3 mm ultra-small size packaging is supported, the requirement of Mini LEDs is met, and high-density adaptability is achieved.

Description

Technical Field

[0001] This invention relates to the field of LED technology, and in particular to an LED packaging device with a metal support. Background Technology

[0002] With the maturity of LED flip chip technology, its market share continues to rise and it is gradually replacing traditional upright chips that require bonding wires. Flip chips are directly connected to the package holder through pads and metal solder, eliminating the need for wire bonding. They have advantages such as compact structure and short heat dissipation path, and are especially suitable for high power and high density packaging scenarios.

[0003] The current mainstream flip chip packaging bracket solutions and their limitations are as follows:

[0004] 1. BT resin substrate: It adopts a resin insulating layer + metal circuit structure, has a low thermal conductivity, is only suitable for low power applications, and has a high cost.

[0005] 2. Ceramic substrate: Although it has excellent thermal conductivity, its manufacturing cost is extremely high, making it difficult to popularize in the low-to-mid-end market;

[0006] 3. EMC bracket: Although thermal conductivity is improved by removing the insulating layer, the structural design of "consistent spacing between upper and lower pads" limits even large-size chips like 40mil*40mil to a pad spacing of only 0.2mm. This places high demands on the precision of the matching PCB board and pick-and-place machine, resulting in a significant decrease in yield. For chips like 15mil*30mil, the pad spacing is 0.15mm, and for many small and medium-sized chips, the pad spacing is even smaller. If an EMC bracket is used to package LED beads, it will be impossible to use it on a large scale.

[0007] Therefore, the market urgently needs an LED packaging device with a metal support that combines high heat dissipation, low cost, and compatibility with small and medium-sized flip chips, in order to overcome the limitations of existing technologies in terms of power density, packaging yield, and cost control. Summary of the Invention

[0008] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes an LED packaging device with a metal support.

[0009] One embodiment of the present invention provides a technical solution to solve its technical problem: an LED packaging device with a metal support, comprising a first metal sheet, a second metal sheet, a flip chip, and a phosphor layer;

[0010] The first metal sheet and the second metal sheet are arranged opposite each other in the horizontal direction. The lower surface of the first metal sheet is provided with a first groove, and the lower surface of the second metal sheet is provided with a second groove arranged opposite to the first groove. The surfaces of the first metal sheet and the second metal sheet are provided with an electroplated layer.

[0011] The positive electrode of the flip chip is soldered to the upper surface of the first metal sheet, and the negative electrode is soldered to the upper surface of the second metal sheet;

[0012] The fluorescent adhesive layer covers the outer layer of the flip chip, fills the gap between the first metal sheet and the second metal sheet, and fills the first groove and the second groove.

[0013] As one of the preferred embodiments of the present invention, the thickness of the first metal sheet and the second metal sheet is set to 0.05-0.5 mm.

[0014] As one of the preferred embodiments of the present invention, the depth of the first groove and the second groove are set to 10-100μm and the width is set to 0.08-0.3mm.

[0015] As one of the preferred embodiments of the present invention, a first pad area is provided on the upper surface of the first metal sheet, a second pad area is provided on the upper surface of the second metal sheet, a third pad area is provided on the lower surface of the first metal sheet, and a fourth pad area is provided on the lower surface of the second metal sheet. The distance between the center of the first pad area and the center of the second pad area is S1, and the distance between the center of the third pad area and the center of the fourth pad area is S2, where S2 / S1≥2.

[0016] As one of the preferred embodiments of the present invention, the first metal sheet and the second metal sheet are made of copper, iron or aluminum alloy.

[0017] As one of the preferred embodiments of the present invention, the spacing S3 between the positive electrode and the negative electrode of the flip chip is set to 0.06-0.2mm.

[0018] As one of the preferred embodiments of the present invention, the fluorescent adhesive layer is composed of two-component silicone, phosphor and SiO2, or is composed of two-component epoxy resin, phosphor and SiO2.

[0019] The beneficial effects of this invention are as follows: An LED packaging device with a metal support includes a first metal sheet, a second metal sheet, a flip chip, and a phosphor layer; the first and second metal sheets are arranged opposite each other in the horizontal direction, a first groove is provided on the lower surface of the first metal sheet, and a second groove is provided on the lower surface of the second metal sheet opposite to the first groove; the positive electrode of the flip chip is soldered to the upper surface of the first metal sheet, and the negative electrode is soldered to the upper surface of the second metal sheet; the phosphor layer covers the outer layer of the flip chip, fills the gap between the first and second metal sheets, and fills the first and second grooves; an electroplated layer is provided on the surface of the first and second metal sheets; by filling the gap between the flip chip and the first and second metal sheets with the phosphor layer to form an insulating layer, the mounting short circuit rate is reduced to ≤0.01%; in terms of heat dissipation performance, the junction temperature is reduced by 25-30℃ compared to the EMC support, and the lifespan is extended by 50%; at the same time, the steps of solder resist coating and secondary encapsulation are eliminated, reducing production costs by 40%; it supports ultra-small size packaging of 0.6×0.3mm, meets the needs of Mini LED, and has high-density adaptability. Attached Figure Description

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0021] Figure 1 This is a schematic diagram of the structure of an LED packaging device with a metal support.

[0022] Figure 2 An exploded view of an LED packaging device with a metal support.

[0023] Figure 3 This is a schematic diagram of the first part of an LED packaging device with a metal support.

[0024] Figure 4 This is a schematic diagram of the second part of an LED packaging device with a metal support.

[0025] Figure 5 A schematic diagram of a structure where a groove is created by locally thinning a metal support.

[0026] Figure 6 A schematic diagram of a structure for machining through holes in a metal bracket;

[0027] Figure 7 This is a schematic diagram of a structure for soldering flip chips onto a metal support. Detailed Implementation

[0028] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0029] In the description of this invention, "multiple" means two or more; "greater than," "less than," and "exceeding" are understood to exclude the stated number; "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0030] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0031] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to a fixed connection, a detachable connection, or an integrally formed connection; they can refer to a mechanical connection; they can refer to the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0032] Reference Figures 1 to 7 An LED packaging device with a metal support includes a first metal sheet 10, a second metal sheet 20, a flip chip 30, and a phosphor layer 40.

[0033] The first metal sheet 10 and the second metal sheet 20 are arranged opposite to each other in the horizontal direction. The lower surface of the first metal sheet 10 is provided with a first groove 11, and the lower surface of the second metal sheet 20 is provided with a second groove 21 arranged opposite to the first groove 11.

[0034] The positive electrode of the flip chip 30 is soldered to the upper surface of the first metal sheet 10, and the negative electrode is soldered to the upper surface of the second metal sheet 20;

[0035] The fluorescent adhesive layer 40 covers the outer layer of the flip chip 30, fills the gap between the first metal sheet 10 and the second metal sheet 20, and fills the first groove 11 and the second groove 21.

[0036] In this invention, the manufacturing process of the LED packaging device is as follows:

[0037] 1) ① Provide a metal bracket 50, clean the surface of the metal bracket 50 and electroplate a nickel layer, tin layer or silver layer; the manufacturing process of the metal bracket 50 is as follows: 1. Refer to Figure 5 1. Take a sheet of metal with a thickness of 0.05-0.5mm, and then locally thin the lower surface of the metal sheet to create a groove 51. The metal sheet can be copper, iron, or aluminum alloy; 2. Refer to Figures 6-7 , Figure 6 (a) is a top view of the metal bracket 50. Figure 6 (b) is a bottom view of the metal bracket 50. Through holes 52 are punched in the metal sheet to form several sets of mutually spaced first metal sheets 10 and second metal sheets 20. A first groove 11 is formed on the lower surface of the first metal sheet 10 and a second groove 21 is formed on the lower surface of the second metal sheet 20. The second groove 21 is arranged opposite to the first groove 11. Preferably, the depth of the first groove 11 and the second groove 21 is set to 10-100μm and the width is set to 0.08-0.3mm. ② High-temperature solder paste (tin-antimony alloy, high-lead alloy, gold-tin alloy, etc.) is coated on the upper surface of the first metal sheet 10 and the upper surface of the second metal sheet 20.

[0038] 2) ① Mount flip chips 30 (size 0.1×0.2mm to 1.0×1.0mm) in the solder paste area. Preferably, the spacing S3 between the positive and negative terminals of the flip chips 30 is set to 0.06-0.2mm; ② Reflow soldering (peak temperature ≥260℃, time 10-30s) to form die bond.

[0039] 3) ① Cover the surface of the metal support 50 and the flip chip 30 with semi-solid fluorescent adhesive (i.e., fluorescent adhesive layer 40, containing silicone or epoxy resin, phosphor, and SiO2); ② Vacuum press (pressure 0.5-1.5MPa, temperature 80-100℃, vacuum degree ≤10Pa) to liquefy the fluorescent adhesive and fill the gap between the pads; ③ Heat curing (150-160℃, time 30-240min) to make the fluorescent adhesive on the surface of the flip chip 30 flatly cover it, and fill the gap between the first groove 11, the second groove 21 and the gap between the first metal sheet 10 and the second metal sheet 20 with fluorescent adhesive and cure it to form a dense insulating layer;

[0040] 4) Use a water-cooled scribing machine or a laser scribing machine (wavelength 355nm, power 5-10W) to separate the metal bracket 50 along the preset cutting path to obtain independent LED devices.

[0041] Reference Figures 2-4The upper surface of the first metal sheet 10 is provided with a first pad area 12, the upper surface of the second metal sheet 20 is provided with a second pad area 22, the lower surface of the first metal sheet 10 is provided with a third pad area 13, and the lower surface of the second metal sheet 20 is provided with a fourth pad area 23. The distance S1 between the center of the first pad area 12 and the center of the second pad area 22 is set to 0.8-2mm, which can adapt to small and medium-sized chips such as 0409, 0518, and 1020. The distance S2 between the center of the third pad area 13 and the center of the fourth pad area 23 is set to 0.3-1.0mm, which meets the accuracy of conventional pick-and-place machines (±0.15mm). Among them, S2 / S1≥2, ensuring that the packaged LED bead is both compatible with small chips and low-precision placement.

[0042] In some alternative embodiments, a groove with a depth of 0.05-0.1 mm is formed around the pad area by semi-etching to limit phosphor overflow and improve packaging consistency.

[0043] As a first embodiment of the present invention (1.0×1.0mm device), ① Metal support 50: using copper substrate, the distance S1 between the center of the first pad area 12 and the center of the second pad area 22 is set to 0.15mm; the distance S2 between the center of the third pad area 13 and the center of the fourth pad area 23 is set to 0.5mm; ② Flip chip 30: flip blue light chip, size 0.7×0.7mm, power 2W; ③ Phosphor layer 40: thickness 150μm, containing YAG phosphor (concentration 45wt%); ④ Performance: thermal resistance ≤2.0℃ / W, mounting yield ≥99.5%.

[0044] As a second embodiment of the present invention (0.6×0.3mm device), ① Metal support 50: using copper substrate, the distance S1 between the center of the first pad area 12 and the center of the second pad area 22 is set to 0.1mm, and the distance S2 between the center of the third pad area 13 and the center of the fourth pad area 23 is set to 0.4mm; ② Flip chip 30: flip blue light chip, size 0.7×0.7mm, power 2W; ③ Phosphor adhesive layer 40: SiO2 nanoparticles (concentration 5wt%) are added to enhance fluidity, and the gap height is ≤20μm; ④ Performance: insulation withstand voltage: ≥500V (DC), no short circuit risk.

[0045] In some embodiments, the local thinning process of the metal support 50 can be carried out in the following ways: ① Etching: Using photoresist masking technology, the area to be thinned is defined on the lower surface of the metal support 50, and the unmasked area is thinned to the target thickness (e.g., 10μm-100μm) by chemical etching; ② Laser thinning: Through pattern design, the area to be thinned is defined on the lower surface of the metal support 50, and the area to be thinned is thinned to the target thickness (e.g., 10μm-100μm) by laser thinning technology; ③ Grinding thinning: Using a micro milling cutter, grinding cutter, or grinding wheel, the area to be thinned on the lower surface of the metal support 50 is ground to the target thickness (e.g., 10μm-100μm); ④ Mold stamping thinning: Using a precision mold, the area to be thinned is designed as a protrusion, and the sheet metal support 50 is impacted to form a groove in the area to be thinned by pressure, with the depth of the groove being the target thickness (e.g., 10μm-100μm).

[0046] The advantages of this invention are:

[0047] 1) Significantly improved thermal performance

[0048] ① Optimized thermal conductivity: Through a single-layer all-metal structure (such as copper substrate, thermal conductivity ≥380 W / m·K), the thermal resistance of the insulating layer of traditional BT resin substrate (≤0.3 W / m·K) is completely eliminated, and a direct heat dissipation channel is established from the chip to the surface of the package. The thermal conductivity is more than 200 times higher than that of BT resin substrate, and the cost is reduced by more than 90% compared with ceramic substrate (such as AlN, 180 W / m·K).

[0049] ② Enhanced temperature control capability: In the 5W high-power flip chip packaging test, the junction temperature of the present invention is 15-20℃ lower than that of the AlN ceramic substrate support, which effectively extends the chip life and improves the stability of light efficiency.

[0050] 2) Breakthrough in pad spacing design

[0051] ① Adaptability expansion: Through local thinning process, the upper layer pad spacing is ≤0.15mm (adapting to small and medium chip electrodes such as 10mil*20mil and 5mil*18mil), while the lower layer pad spacing is ≥0.4mm (meeting PCB mounting requirements). Compared with the existing EMC bracket (with consistent upper and lower layer spacing), the mounting yield is improved by ≥30% (taking EMC3030 package as an example).

[0052] ② Process compatibility: It can be compatible with high-density PCB board designs without changing the precision of downstream pick-and-place machines (such as maintaining equipment precision ±0.15mm), reducing customer upgrade costs.

[0053] 3) Cost and technological advantages

[0054] ① Material cost reduction: The high raw material cost of ceramic substrates is eliminated (the unit price of Al2O3 ceramic substrate is about 30 yuan / K, and the cost of the metal bracket of this invention is ≤1 yuan / K). The cost of BT resin substrate with thermal conductivity ≤0.3W / m·Kd is about 3 yuan / K.

[0055] ② Simplified process: The single-layer metal structure combined with local thinning process reduces the composite processing steps of traditional brackets (metal sheet electroplating, metal sheet punching, plastic injection molding, punching and cutting, etc.), and improves production efficiency by more than 40%.

[0056] 4) Application scenario expansion

[0057] ①Comprehensive power coverage: It can simultaneously adapt to flip chips with low power (0.01W) to high power (10W), breaking through the power limitations of traditional brackets (such as BT resin substrates which only support ≤0.2W).

[0058] ② High-density packaging support: In Mini LED backlighting applications, it supports array packaging with a chip pitch of ≤80μm, meeting the requirements of 4K / 8K display modules for ultra-thinness and high brightness.

[0059] 5) Improved reliability

[0060] ①Structural stability: The pure metal integrated design avoids the thermal expansion coefficient (CTE) mismatch problem of traditional composite supports (such as EMC + metal layer). In the temperature cycling test of -40℃~150℃, the weld cracking rate is reduced by 90%.

[0061] ② Corrosion resistance: Through surface nickel / gold plating process (post-etching treatment), the metal substrate 50 has better sulfur resistance than the ceramic substrate in a humid heat environment of 85℃ / 85%RH, and its lifespan is extended by 30%.

[0062] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications and substitutions are all included within the scope defined by the claims of this application.

Claims

1. An LED package device having a metal bracket, characterized by: It includes a first metal sheet (10), a second metal sheet (20), a flip chip (30), and a phosphor layer (40); The first metal sheet (10) and the second metal sheet (20) are arranged opposite to each other in the horizontal direction. The lower surface of the first metal sheet (10) is provided with a first groove (11), and the lower surface of the second metal sheet (20) is provided with a second groove (21) arranged opposite to the first groove (11). The positive electrode of the flip chip (30) is soldered to the upper surface of the first metal sheet (10), and the negative electrode is soldered to the upper surface of the second metal sheet (20); The fluorescent adhesive layer (40) covers the outer layer of the flip chip (30), fills the gap between the first metal sheet (10) and the second metal sheet (20), and fills the first groove (11) and the second groove (21).

2. The LED packaging device with a metal holder according to claim 1, wherein: The thickness of the first metal sheet (10) and the second metal sheet (20) is set to 0.05-0.5 mm.

3. The LED packaging device with a metal holder according to claim 1, wherein: The depth of the first groove (11) and the second groove (21) are set to 10-100μm, and the width is set to 0.08-0.3mm.

4. The LED packaging device with a metal holder according to claim 1, wherein: The upper surface of the first metal sheet (10) is provided with a first pad area (12), the upper surface of the second metal sheet (20) is provided with a second pad area (22), the lower surface of the first metal sheet (10) is provided with a third pad area (13), the lower surface of the second metal sheet (20) is provided with a fourth pad area (23), the distance between the center of the first pad area (12) and the center of the second pad area (22) is S1, the distance between the center of the third pad area (13) and the center of the fourth pad area (23) is S2, and S2 / S1≥2.

5. The LED packaging device with a metal holder according to claim 1, wherein: The first metal sheet (10) and the second metal sheet (20) are made of copper, iron or aluminum alloy.

6. The LED packaging device with a metal holder according to claim 1, wherein: The distance S3 between the positive electrode and the negative electrode of the flip chip (30) is set to 0.06-0.2mm.

7. The LED packaging device with a metal holder according to claim 1, wherein: The fluorescent adhesive layer (40) is composed of two-component silicone, phosphor and SiO2, or two-component epoxy resin, phosphor and SiO2.

Images