CN103956356A - Efficient heat conducting large-power LED integration package structure - Google Patents

Abstract

The invention belongs to the technical field of semiconductor lighting devices, and specifically relates to a high-efficiency thermal conduction high-power LED integrated packaging structure. It includes a first conductive plate, a first thermally conductive insulating plate, a second conductive plate, a second thermally conductive insulating plate and a number of LED chips; the conductive plate is directly used as the positive and negative electrodes of the circuit connection; the conductive plate and the thermally conductive insulating plate are arranged at intervals It forms a sandwich structure, and the interface is coated with insulating glue with high thermal conductivity; the bottom of the LED chip is directly bonded to the surface of the lower conductive plate; the LED chips are connected in parallel, series or parallel-series combination to form a single LED packaging module, and then combined into a more The high-power LED module increases the voltage of the module and reduces the design requirements of the power supply; the entire integrated packaging structure can be fixed mechanically without preparing a printed circuit board, the process is simple and reliable, and the packaging cost is reduced; the packaging structure is suitable for Visible lighting, UV radiation and special lighting applications.

Description

A high-efficiency heat-conducting high-power LED integrated packaging structure

technical field

The invention belongs to the technical field of semiconductor lighting devices, and in particular relates to a high-efficiency heat-conducting high-power light-emitting diode (LED) integrated packaging structure.

Background technique

With the rapid development of semiconductor technology, light-emitting diodes (LEDs), with their advantages of small size, long life, high reliability, and adjustable brightness, have gradually entered various visible light lighting and ultraviolet lighting products. Irradiation applications. As people's requirements for lighting applications change and the demand for high luminous flux and high radiant flux applications increases, the demand for high-power LEDs continues to grow, and the specific requirements are also constantly changing. For example, high pole lights, construction machinery, port machinery, marine engineering equipment, searchlights, car headlights, projectors, traffic camera lights, squid fishing lights, stadium lights, etc. not only need high-efficiency, energy-saving, high-power, high-intensity light sources, but also The power density is very high, and there are strict requirements and restrictions on the size and volume of the lamps; and in industrial fields such as ultraviolet curing, photochemical synthesis and photobiological modification, the power requirements of the applied ultraviolet light source even reach the kilowatt level or above.

With the increase of the power density of LED lamps, the problem of heat dissipation has become one of the key obstacles restricting the commercialization of high-power LEDs. Especially for LED lamps above 200 W, the heat dissipation characteristics seriously affect the performance of the lamps. The existing high-power LED packaging mainly adopts the direct fixed chip (Chips on board, COB) integrated packaging technology, that is, the LED chip is directly bonded on the printed circuit board, and then wire bonding is performed, and then the chip and the chip are bonded with organic glue. Lead wire encapsulation protection technology. Although there have been many researches and patents trying to improve the heat dissipation characteristics of COB packaging, due to the inevitable problems caused by the large number of layers of the packaging structure, the low thermal conductivity of insulating materials and sealing adhesive materials, and the small thermal contact area of the chip, resulting in The efficiency of heat dissipation from the chip to the heat sink is low, which limits the heat dissipation characteristics of the LED integrated package and affects the performance and reliability of high-power LED lamps.

At present, there are mainly two structures for LED chip-scale packaging: planar packaging structure and vertical packaging structure. The P-type and N-type electrodes of the LED chip with a planar packaging structure are on the same side of the LED, which is convenient for high-power integrated packaging, but the same side of the electrodes leads to lateral crowding of the current, high local heat generation, and the large coverage of the P electrode affects the light output of the chip. efficiency. The two electrodes of the vertical structure LED chip are respectively on both sides of the LED epitaxial layer, so that almost all the current flows vertically through the LED epitaxial layer, the current density is uniform, the problem of current crowding is avoided, the luminous efficiency is improved, and the problem of the P pole is solved. The problem of light absorption, under high power density, its light extraction efficiency can reach 3 times that of planar structure LED. Vertical packaging structure chips are gradually becoming the mainstream of LED chips. Since the positive and negative poles of the chip in the vertical packaging structure are located above and below the chip respectively, there must be an insulating layer between the chip and the metal heat dissipation base plate during high-power integrated packaging. At present, most of the mainstream high-power packaging structures use alumina ceramics as the insulating layer, and the LED chip is packaged on the metal film coating of the alumina substrate. However, the thermal conductivity of alumina ceramics is only about 25 W/(m K), which is much smaller than that of commonly used metals such as aluminum 230 W/(m K). The difference between the two is an order of magnitude, and the heat cannot be effectively conducted from the chip. . Therefore, in high-power LED packaging, this method has a poor heat conduction effect, which affects the heat dissipation of the lamp and restricts the improvement of the power density of the LED lamp.

In addition, most printed circuit boards for LED packaging in the prior art use copper foil to make circuits. However, the cross-sectional area of copper foil is small, so the current carrying capacity is limited, which also limits the power density of LED lamps.

Contents of the invention

In view of the deficiencies of the prior art, the purpose of the present invention is to provide an integrated packaging structure of high-power LEDs with high thermal conductivity, so as to realize the development of high-power LED lamps with high packaging power per unit area.

A high-efficiency heat-conducting high-power LED integrated packaging structure provided by the present invention includes a first conductive plate, a first heat-conducting insulating plate, a second conducting plate, a second heat-conducting insulating plate and several LED chips; the first conducting plate 1. The first thermally conductive insulating plate, the second conductive plate and the second thermally conductive insulating plate are arranged sequentially from top to bottom, and the contact interface of the upper and lower plates is coated with high thermal conductive insulating glue; the first conductive plate and the second conductive plate are individually or separately As the positive and negative poles of circuit connection; the plurality of LED chips are glued and arranged on the second conductive plate, which is connected to the positive and negative poles of circuit connection.

The above-mentioned first conductive plate includes two left and right plates, which are respectively a positive electrode conductive plate and a negative electrode conductive plate, which are respectively used as positive and negative electrodes for circuit connection; Compatible with the positive conductive plate and the negative conductive plate, the plurality of LED chips are placed between the positive conductive plate and the negative conductive plate, and the electrodes of the LED chips are respectively connected to the positive conductive plate and the negative conductive plate through gold wires.

A plurality of openings are provided on the first conductive plate and the first insulating plate, and a plurality of LED chips are placed in the openings, and electrodes of the LED chips are respectively connected to the first and second conductive plates.

The above-mentioned several LED chips are of planar structure or vertical structure, or a mixture of planar structure and vertical structure.

The above-mentioned first conductive plate and the second conductive plate are metal plates with high thermal conductivity or conductive non-metallic plates; the first heat-conducting and insulating plates and the second heat-conducting and insulating plates are plates with both thermal conductivity and insulation.

The above-mentioned metal plate is an aluminum plate or a copper plate; the non-metallic plate is a silicon carbide plate; the first heat-conducting insulating plate and the second heat-conducting insulating plate are aluminum nitride plates.

When a plurality of LED chips are adhered on the second conductive plate, the chip bottom sheet is directly bonded to the second conductive plate by high thermal conductivity adhesive, solder or eutectic bonding technology.

The above-mentioned high thermal conductivity insulating adhesive is made of aluminum nitride or beryllium nitride high thermal conductivity insulating powder mixed bonding material, and the thermal conductivity is above 120 W/(m K); Made of silver-copper glue material, the thermal conductivity is over 120 W/(m·K).

In the present invention, the above-mentioned first conductive plate, first heat conduction and insulation plate, second conduction plate and second heat conduction and insulation plate are fixed and compressed by screws or other mechanical means.

In the present invention, the LED chip can be an ultraviolet LED chip, packaged into a high-power ultraviolet LED light source module with high packaging power per unit area, and a plurality of light source modules are combined into a higher power light source module; the ultraviolet LED light source module or module The group can encapsulate other components such as quartz lenses, resin materials or silicone oil baths; it is used in ultraviolet irradiation applications such as photocuring, sterilization, photochemical synthesis, photobiological modification, material modification, and material surface treatment. Package-free LED chips can also be used, multi-color LED chips can be used to mix light, and chips can also be packaged with fluorescent powder methods such as fluorescent powder glue coating, remote phosphor powder boards and other technologies to package high-power white light with high packaging power per unit area. LED lamps; high-power white LED lamps can be used in visible lighting fields such as high pole lights, stadium lighting, searchlights, movie projection lights, etc. Protective devices can be packaged and used in lighting fields for special occasions such as port machinery and marine equipment in high-salt environments; the high unit area packaged power LED lamps can be used as special light sources with small size, high heat dissipation requirements, and flexible design, such as Projector lamps, automobile headlights, road monitoring camera fill lights, etc.; the LED lamps use LED chips of different colors, and can be used as special light sources such as fish-collecting lights and plant fill lights.

Compared with the existing packaging structure, the present invention has the following advantages:

1. The present invention adopts a sandwich structure in which conductive plates and heat-conducting insulating plates are distributed at intervals to realize high-power integrated packaging with high packaging power per unit area.

2. In the present invention, the conductive plate in the packaging structure is directly used as the positive and negative electrodes of the circuit connection. The conductive plate can directly weld the wire to draw the current, and the cross-sectional area of the conductive plate is more than 10 times higher than that of the printed circuit board wire, so that The current load capacity of the LED integrated package light source module is more than 10 times larger than that of the printed circuit board, which greatly improves the current load capacity, improves the packaging power per unit area, and solves the current-carrying limitation problem of the printed circuit board.

3. In the high-power LED integrated packaging structure of the present invention, the LED chip and the conductive plate are directly bonded, which reduces the number of layers of different materials and thermal conductivity between the LED chip and the radiator, and the high thermal conductivity is arranged between the conductive plates. The insulation board effectively reduces the internal thermal resistance, improves the heat export efficiency of the LED chip, and improves the heat dissipation performance of the LED lamp.

4. The present invention adopts the method of parallel-serial combination, several LED chips first form a high-power package module, and then multiple modules form a module with higher power. By changing the parallel-series combination of chips and modules, the working current and working voltage of LED lamps can be conveniently and effectively set, which not only realizes high-power, high-voltage LED module packaging, but also reduces the current design of the driving power supply. Require.

5. The packaging structure of the present invention can be installed and fixed mechanically; the thermally conductive insulating plate can be processed by laser processing, and the processing is simple; and the conductive plate is directly used as the positive and negative electrodes of the circuit connection, avoiding the design and complexity of the printed circuit board The manufacturing process; therefore, the packaging structure of the present invention simplifies the manufacturing process, can effectively improve the yield and reduce the manufacturing cost.

Description of drawings

FIG. 1 is a schematic cross-sectional view of an integrated packaging structure of a high-efficiency heat dissipation high-power LED according to the present invention.

Fig. 2 is a cross-sectional view of an example of an integrated package module using a vertical structure LED chip according to the present invention.

Fig. 3 is a top view of an example of an LED chip integrated packaging module with a vertical structure according to the present invention.

Fig. 4 is a cross-sectional view of an example of an LED chip integrated packaging module with a planar structure according to the present invention.

Fig. 5 is a top view of an example of an LED chip integrated packaging module with a planar structure according to the present invention.

Labels in the figure: 1—the first conductive plate; 2—the first thermally conductive insulating plate; 3—the second conductive plate; 4—the second thermally conductive insulating plate; 5—high thermal conductive insulating glue; 6—LED chip; 7—high thermal conductive Conductive glue; 8—gold wire; 9—screw; 10—opening; 11—positive conductive plate; 12—negative conductive plate; 13—vertical structure LED chip; 14—planar structure LED chip.

Detailed ways

Below in conjunction with accompanying drawing and example, the present invention will be further described. The described embodiments are only some of the embodiments of the invention. All other embodiments without creative achievements based on the embodiments of the present invention belong to the protection scope of the present invention.

Referring to Fig. 1, a high-power LED integrated packaging structure with high heat dissipation efficiency of the present invention includes: a first conductive plate 1, a first thermally conductive insulating plate 2, a second conductive plate 3, a second thermally conductive insulating plate 4 and several LED chips 6 , the first conductive plate 1, the second conductive plate 3, the first thermally conductive insulating plate 2, and the second thermally conductive insulating plate 4 are arranged at intervals, and the contact interface is coated with a thermal conductivity of more than 120 W/(m·K) High thermal conductivity insulating glue 5 to increase the thermal contact area. The first conductive plate 1 and the second conductive plate 3 are made of high thermal conductivity materials such as copper and aluminum, and are directly used as positive and negative electrodes for circuit connection. The first conductive plate 1 and the second conductive plate 3 are insulated by the first thermally conductive insulating plate 2, while the second thermally conductive insulating plate 4 plays the role of insulating the second conductive plate 3 from the external radiator or lamp housing. The LED chips 6 are arranged on the second conductive plate 3 in a certain order, and the bottom of the chip is directly bonded to the conductive plate through the high thermal conductivity conductive glue 7 .

Based on the structure described in Fig. 1, Fig. 2 and Fig. 3 are a kind of high-efficiency heat dissipation and high-power integrated packaging module adopting vertical structure LED chips of the present invention, including: a first conductive plate 1, a first heat-conducting insulating plate 2, a second Two conductive plates 3, a second thermally conductive insulating plate 4 and a vertical structure LED chip 13, the first conductive plate 1, the second conductive plate 3, the first thermally conductive insulating plate 2, and the second thermally conductive insulating plate 4 are arranged at intervals, 1 The interfaces of /2, 2/3, and 3/4 are coated with high thermal conductivity insulating glue 5, and are fixed and pressed with screws 9. There are several openings 10 of a certain area on the first conductive plate 1 and the upper thermal conductive insulating plate 3, The surface of the second conductive plate 3 is exposed, and the vertical structure LED chips 13 are arranged on the second conductive plate 3 in a certain order. A plurality of vertical structure LED chips 13 are connected in parallel, the electrodes on the top of the chip are welded on the first conductive plate 1 through the gold wire 8 , and the bottom of the chip is directly bonded on the second conductive plate 3 through the high thermal conductivity conductive glue 7 .

Figure 4 and Figure 5 are a high-efficiency heat-dissipating high-power integrated packaging module using a planar structure LED chip of the present invention, including: positive conductive plate 11, negative conductive plate 12, first heat-conducting insulating plate 2, second conductive plate 3 and LED chip 14 with planar structure. The positive conductive plate 11 and the negative conductive plate 12 are deformations of the first conductive plate 1 described in FIG. For insulation, the interface between the conductive plate and the thermally conductive insulating plate is coated with high thermally conductive insulating glue 5, and the entire packaging module is fixed and pressed with screws 9. A series combination of multiple strings of LED chips is connected in parallel between the positive conductive plate 11 and the negative conductive plate 12 . The top electrode of the planar structure LED chip 14 is welded with gold wire, and the bottom of the chip is directly bonded to the second conductive plate 3 through the high thermal conductivity insulating glue 5 .

The structural design of the present invention mainly adopts a sandwich structure in which the conductive plate and the high thermal conductivity insulating plate are distributed at intervals. The conductive plate is directly used as the positive and negative electrodes, the cross-sectional area is large, and the current carrying capacity is increased by more than 10 times. Several LED chips are connected in parallel and in series. Or parallel-series combination to form a high-power integrated packaging module, and multiple modules are combined to form a higher-power LED module, and finally realize the development of high-efficiency high-power ultraviolet and visible light LED lamps with high packaging power per unit area.

The structural design of the present invention mainly aims to reduce the number of internal heat sinks. The LED chip is directly bonded to the conductive plate by means of high thermal conductivity adhesive, etc., and an insulating plate with high thermal conductivity is used as the insulating layer. The heat of the LED chip is mainly exported The path is: directly from the bottom of the chip → high thermal conductivity glue → second conductive plate → high thermal conductivity insulating glue → second heat conduction insulation plate. The secondary heat export path of the LED chip is: gold wire→first conductive plate→high thermal conductive glue→first thermal conductive insulating plate→high thermal conductive glue→second conductive plate→high thermal conductive glue→second thermal conductive insulating plate. This heat conduction method effectively reduces the thermal resistivity and improves the heat conduction capacity.

The sandwich packaging structure of the present invention can be fixed by mechanical means such as screws, and the conductive plate replaces the printed circuit board, which reduces the production process of thin film technology and solves the problem of complicated process when making printed circuit boards with high thermal conductivity insulating plates such as aluminum nitride plates. The problems of low yield and low current density simplifies the manufacturing process, improves the yield and reduces the manufacturing cost.

Claims (8)

1. A high-efficiency heat-conducting high-power LED integrated package structure, characterized in that: it includes a first conductive plate, a first heat-conducting insulating plate, a second A conductive plate, a second thermally conductive insulating plate, and several LED chips; the first conductive plate, the first thermally conductive insulating plate, the second conductive plate, and the second thermally conductive insulating plate are sequentially arranged from top to bottom, and the contact interface of the upper and lower plates is coated with High thermal conductivity insulating glue; the first conductive plate and the second conductive plate are used as the positive and negative electrodes of the circuit connection alone or respectively; connected. 2. The high-efficiency heat conduction high-power LED integrated packaging structure according to claim 1, characterized in that: the first conductive plate includes two left and right plates, which are respectively a positive electrode conductive plate and a negative electrode conductive plate, which are respectively used for circuit connection The positive and negative poles of the first heat-conducting insulating plate are also divided into left and right plates, the size and shape of which are respectively adapted to the positive conductive plate and the negative conductive plate, and the plurality of LED chips are placed between the positive conductive plate and the negative conductive plate. Between them, the electrodes of the LED chip are respectively connected to the positive conductive plate and the negative conductive plate through gold wires. 3. The high-efficiency heat conduction high-power LED integrated packaging structure according to claim 1, characterized in that: several openings are set on the first conductive plate and the first insulating plate, and several LED chips are placed in the openings, and the LED chips The electrodes are respectively connected to the first and second conductive plates. 4. The high-efficiency heat-conducting high-power LED integrated package structure according to claim 1, 2 or 3, characterized in that: the plurality of LED chips are planar or vertical, or a mixture of planar and vertical. 5. The high-efficiency heat conduction high-power LED integrated packaging structure according to claim 1, characterized in that: the first conductive plate and the second conductive plate are metal plates with high thermal conductivity or conductive non-metal plates; The first thermally conductive insulating plate and the second thermally conductive insulating plate are plates with both thermal conductivity and insulation. 6. The high-efficiency heat-conducting high-power LED integrated package structure according to claim 5, characterized in that: the metal plate is an aluminum plate or a copper plate; the non-metallic plate is a silicon carbide plate; the first heat-conducting insulating plate and The second thermally conductive insulating plate is an aluminum nitride plate. 7. The high-efficiency heat-conducting high-power LED integrated packaging structure according to claim 1, characterized in that: when a plurality of LED chips are adhered and arranged on the second conductive plate, the chip substrate is passed through high thermal-conductive adhesive, solder or eutectic bond. bonding technology directly on the second conductive plate. 8. The high-efficiency heat conduction high-power LED integrated packaging structure according to claim 7, characterized in that: the high heat conduction insulating glue is made of aluminum nitride or beryllium nitride high heat conduction insulating powder mixed bonding material, heat conduction The coefficient is more than 120 W/(m·K); the high thermal conductivity conductive adhesive is made of silver glue or silver-plated copper glue, and the thermal conductivity is more than 120 W/(m·K).