CN201117676Y - High-power light-emitting diode packaging structure with integrated microstructure - Google Patents

Abstract

A high-power light-emitting diode packaging structure with integrated microstructure, mainly including a ceramic sheet, an upper copper sheet and a lower copper sheet, characterized in that the two copper sheets are bonded to the upper and lower surfaces of the ceramic sheet by a direct bonded copper (DBC) process , and a microchannel is provided on the surface or inside of the lower copper sheet. The utility model has the advantages that the light-emitting chip is directly welded on the metal pad, the upper and lower surfaces of the ceramic substrate have copper layers, the thermal mismatch stress is small, the manufacturing cost is low, the structure is compact, and it is beneficial to increase the packaging density, and the microchannel can pass The cooling liquid is added, which greatly improves the heat dissipation capability of the package.

Description

High-power light-emitting diode packaging structure with integrated microstructure

technical field

The utility model relates to a semiconductor device, in particular to a high-power light-emitting diode packaging structure with integrated microstructure.

Background technique

The internal quantum efficiency and external quantum efficiency of a light-emitting diode (LED) determine the total light extraction efficiency and device brightness of the LED. Among the traditional light sources, the luminous efficiency of fluorescent lamps is 60-100lm/W, and that of high-pressure sodium lamps is 60-120lm/W. At present, the luminous efficiency of high-power gallium nitride (GaN)-based white LEDs (blue light + phosphor) is the highest It is only 100lm/W, and the ordinary one is only 30-50lm/W. From the perspective of LED luminescence principle, LED efficiency (external quantum efficiency) is mainly determined by the product of injection efficiency, internal quantum efficiency and light extraction efficiency. Among them, the injection efficiency is related to the material structure and the series resistance of the device, and the internal quantum efficiency is mainly determined by factors such as the quality of crystal growth, the structure of the quantum well, and the damage to the active layer during the device manufacturing process. At present, the internal quantum efficiency of GaN-based LEDs at room temperature is low, only about 30%, while the light extraction efficiency of GaN-based high-power LEDs is even lower, only about 10%, making the efficiency of GaN-based high-power LEDs less than 10%, 90% About 100% of the light cannot be exported and is consumed in the form of heat in the device, resulting in waste of electric energy. What is more serious is that the device heats up and the temperature rises, resulting in a sharp drop in LED light efficiency. At the same time, the chip, bonding wire and packaging materials are seriously aged, shortening the life.

It can be seen from the above analysis that heat dissipation is one of the problems that affect the wide application of LEDs. The general LED packaging structure is shown in Figure 1. The light-emitting chip is welded on the substrate by solder paste, and the substrate and the heat sink are connected by a thermal interface material, so the heat dissipation path is: light-emitting chip-substrate-heat sink-environment. The commonly used substrate is generally MCPCB board, which contains a layer of insulating layer, which has high thermal resistance and affects the heat dissipation effect. The thermal interface material selected between the substrate and the heat sink also has a certain thermal resistance, which increases the difficulty of heat dissipation. After the heat is conducted to the heat sink, the current passive heat dissipation is shown in Figure 1, and the heat is dissipated to the environment through the heat sink. This method can still match the heat dissipation effect when the LED power is small, but as the LED power continues to increase, the heat dissipation increases, and this type of passive heat dissipation structure can no longer meet the heat dissipation requirements of the LED.

Contents of the invention

The purpose of the utility model is to provide a high-power light-emitting diode packaging structure with integrated microstructure for the defects in the prior art.

The utility model mainly comprises: a ceramic sheet, an upper copper sheet and a lower copper sheet, which is characterized in that the upper and lower copper sheets are bonded to the upper and lower surfaces of the ceramic sheet through a direct bonded copper (DBC Directed Bonded Cooper) process, and Microchannels are arranged on the surface or inside of the lower copper sheet. The utility model has the advantages that the light-emitting chip is directly welded on the metal pad, the upper and lower surfaces of the ceramic substrate have copper layers, the thermal mismatch stress is small, the manufacturing cost is low, the structure is compact, and it is beneficial to increase the packaging density, and the microchannel can pass The cooling circulating fluid is added, which greatly improves the heat dissipation capability of the package.

Description of drawings

Figure 1 is a plan view of the existing LED package structure;

The sectional view of the upper copper sheet in Fig. 2a;

The cross-sectional view of the lower copper sheet before the processing of Fig. 2b;

The cross-sectional view of the lower copper sheet after processing in Fig. 2c;

Figure 2d is a cross-sectional view of the upper and lower copper sheets bonded to the ceramic sheet;

Figure 2e is a cross-sectional view of the structure after the metal corrosion process;

Fig. 3a is a cross-sectional view of the structure after the metal diffusion bonding process;

Figure 3b is a cross-sectional view of the upper and lower copper sheets bonded to the ceramic sheet;

Figure 3c is a cross-sectional view of the structure after the metal corrosion process;

Figure 4 is a cross-sectional view of the LED package structure.

11 light-emitting chip, 12 solid crystal layer, 13 metal film layer, 14 insulating layer, 15 metal substrate, 16 welding (bonding) layer, 17 heat sink, 18 silica gel layer containing phosphor, 19 gold wire, 20 packaging adhesive layer, 21 upper copper sheet, 22 lower copper sheet, 23 microchannel, 24 ceramic sheet, 25 chip area and circuit, 31 upper copper sheet, 32 lower copper sheet, 33 microchannel, 34 copper sheet, 35 ceramic sheet, 36 composite copper sheet , 37 chip area and circuit, 41 light-emitting chip, 42 solid crystal layer, 43 chip area and circuit, 44 ceramic sheet, 45 microchannel, 46 lower copper sheet, 47 silica gel layer containing fluorescent powder, 48 gold wire, 49 packaging silica gel layer .

Detailed ways

Embodiment one

Further illustrate the embodiment of the present utility model below in conjunction with accompanying drawing:

Referring to Fig. 2a and Fig. 2b, select two pieces of high-purity oxygen-free copper sheets with appropriate thickness, the thickness of the upper copper sheet 21 is 0.3mm, and the thickness of the lower copper sheet 22 is 5mm.

Using mechanical processing technology, a microchannel 23 with a square cross-section is fabricated on the surface of the lower copper sheet 22, and the side length of the square is 2 mm, as shown in FIG. 2c. Microchannels can be arranged in serpentine or M-shaped single-layer or multi-layer structures.

Two copper sheets are simultaneously bonded to the upper and lower surfaces of an alumina ceramic sheet 24 by using a direct bonded copper (DBC) process, and the thickness of the ceramic sheet 24 is 0.63mm, see FIG. 2d.

Using a metal corrosion process, a chip area and a circuit structure 25 are formed on the upper copper sheet 21 (while protecting the lower copper sheet 22), that is, a packaging substrate with an integrated microchannel structure is prepared, as shown in FIG. 2e.

Embodiment two

Embodiment 2 is the same as Embodiment 1, except that two high-purity oxygen-free copper sheets with appropriate thicknesses are first selected, wherein the upper copper sheet 31 has a thickness of 1mm, and the lower copper sheet 32 has a thickness of 3mm.

A square microchannel 33 is fabricated on the surface of the lower copper sheet 32 by mechanical processing technology, and the side length of the square is 2 mm. And the metal diffusion bonding process is used to bond the two pieces of copper together, see Figure 3a.

Another copper sheet 34 (thickness: 0.2mm) and composite copper sheet 36 are bonded to the upper and lower surfaces of the ceramic sheet 35 by using DBC process. The material of the ceramic sheet is aluminum nitride and the thickness is 1mm, see Fig. 3b.

Using a metal corrosion process, a chip area and a circuit structure 37 are formed on the copper sheet 34 (while protecting the lower copper sheet 31), that is, another packaging substrate with an integrated microchannel structure is prepared, as shown in FIG. 3c.

Fig. 4 is the structural diagram of the LED packaging substrate prepared by the utility model, the light-emitting chip 41 is fixed on the chip area 43 through the crystal-bonding layer 42, the light-emitting chip 41 is connected with the circuit through the gold wire 48, and the lower copper sheet 45 adopts the DBC process and the ceramic sheet 44 are bonded together, the lower copper sheet 45 is provided with a microchannel 46, the upper surface of the light-emitting chip 41 is provided with a phosphor-containing silica gel layer 47, and the exterior is an encapsulating silica gel layer 49.

In the above embodiments, the cross-sectional shape of the microchannel structure can also be rectangular or semicircular, and the microchannels can be arranged in a serpentine or M-shaped single-layer or multi-layer structure.

Claims (4)

1. the high power LED package structure of an integrated microstructure, mainly comprise: potsherd, last copper sheet and following copper sheet, it is characterized in that the described copper sheet of going up is bonded in the potsherd upper and lower surface with following copper sheet by Direct Bonding copper (DBC) technology, and be provided with the microchannel on following copper sheet surface or inside.

2. the high power LED package structure of integrated microstructure according to claim 1 is characterized in that described going up on the copper sheet has chip region and circuit structure.

3. the high power LED package structure of integrated microstructure according to claim 1 is characterized in that described microchannel is snakelike or M shape single or multiple lift structure, and its cross sectional shape can be square or rectangular or semicircle.

4. the high power LED package structure of integrated microstructure according to claim 1 is characterized in that described potsherd is aluminium oxide or aluminium nitride or ceramic material.

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