CN104465975A - Power-type LED integrated packaging structure - Google Patents

Abstract

The invention discloses a power-type LED integrated packaging structure which comprises a radiating heat tube, a CuW heat sink, a Si substrate, an LED chip and a sapphire. The radiating heat tube is arranged at the bottommost end of the structure. The CuW heat sink is arranged on the radiating heat tube. The Si substrate is arranged on the CuW heat sink. The LED chip is arranged on the Si substrate. The sapphire is arranged on the LED chip. By the adoption of the technical scheme, the current density of the chip is increased; the heat dissipation effect is further improved; a silver reflection layer eliminates the light blocking phenomenon caused by an electrode and a lead, and therefore the structure has optimal characteristics with respect to electricity, light, heat and the like.

Description

A power type LED integrated packaging structure

technical field

The invention relates to the technical fields of optics, heat, electricity, mechanics, structure and technology of LED packaging, and in particular to a power LED integrated packaging structure.

Background technique

With the development of lighting technology, high-power white LED will be the core of future lighting. As a new type of light source, white LED has the advantages of long life, small size, energy saving, high efficiency, fast response, shock resistance, and no pollution compared with traditional light sources. It is considered to be a "green lighting source" that can enter the field of general lighting, especially The birth of high-power white LEDs is called "the fourth revolution in the field of lighting" by the industry, and it is an inevitable trend for LEDs to be widely used in general lighting.

At present, the driving current of many high-power LEDs reaches 350mA, 700mA, or even 1A, which will cause heat accumulation inside the chip, resulting in a series of problems such as drift of emission wavelength, decrease in light extraction efficiency, accelerated aging of phosphor powder, and shortened service life. The industry has made a lot of efforts on the heat dissipation of high-power LEDs: by optimizing the design of the chip epitaxial structure, using surface roughening technology to improve the quantum efficiency inside and outside the chip, reducing the lattice oscillation caused by non-radiative recombination, and fundamentally reducing Reduce the load of heat dissipation components; by optimizing the packaging structure and materials, choose to use aluminum-based metal core printed circuit boards, ceramics, composite metal substrates and other methods to speed up the heat dissipation from the epitaxial layer to the heat dissipation substrate. Most manufacturers also use heat sinks in high-performance occasions, relying on methods such as strong convection heat dissipation to promote high-power LED heat dissipation. Even so, a single LED product is currently only at the level of 1-10W, and the heat dissipation capacity still needs to be improved.

In addition, gallium nitride is selected as the material for making LED chips. The third-generation semiconductor material represented by gallium nitride is a semiconductor material that has received much attention internationally in the past decade. It is used in white light LEDs, short-wavelength lasers, ultraviolet detectors and It has broad application prospects in high temperature and high power devices. The most ideal substrate for gallium nitride growth is naturally gallium nitride single crystal material, which can greatly improve the crystal quality of the epitaxial film, reduce the dislocation density, improve the working life of the device, improve the luminous efficiency, and increase the working current density of the device .

And choose tungsten-copper alloy as the heat sink of the integrated package structure, because it has both the low expansion characteristics of tungsten and the high thermal conductivity of copper, and its thermal expansion coefficient and thermal conductivity can be changed by adjusting the composition of tungsten copper, so It provides a wider range of applications for tungsten copper. Because tungsten copper material has high heat resistance and good thermal conductivity, and at the same time has a thermal expansion coefficient that matches silicon wafers, gallium arsenide and ceramic materials, it is widely used in semiconductor materials.

Contents of the invention

In order to overcome the deficiencies in the prior art, the object of the present invention is to provide a power LED integrated packaging structure, which is applied to the production and design of high-power LEDs for lighting, and the structure has optimal characteristics in terms of electricity, light, heat, etc. , Effectively improve the performance and light efficiency of LED.

In order to achieve the above-mentioned technical purpose and achieve the above-mentioned technical effect, the present invention is realized through the following technical solutions:

A power type LED integrated packaging structure, comprising a heat dissipation heat pipe, a CuW heat sink, a Si substrate, an LED chip and sapphire, the heat dissipation heat pipe is arranged at the bottom of the structure, and the CuW heat dissipation pipe is arranged above the heat dissipation heat pipe A heat sink, the Si substrate is disposed above the CuW heat sink, the LED chip is disposed above the Si substrate, and the sapphire is disposed above the LED chip.

Further, the LED chip includes a P electrode and an N electrode, a metal bump is respectively arranged under the P electrode and the N electrode, and the outside of the Si substrate and the LED chip is connected by a gold wire, and the A silver photoreflective layer is arranged between the P electrode and the PN junction.

Compared with the prior art, the present invention has the following beneficial effects:

In the technical solution of the present invention, the light is taken out from the sapphire substrate without taking out the current diffusion layer. Since the light is not taken from the current diffusion layer, the opaque current diffusion layer can be thickened, which increases the current density of the chip; at the same time, this This structure can also conduct the heat of the PN junction directly to the Si substrate and CuW heat sink with high thermal conductivity through the metal bumps. The application of heat pipe technology further improves the heat dissipation effect; the silver reflective layer eliminates the light blocking of electrodes and leads , so this structure has the best characteristics in terms of electricity, light and heat.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention and accompanying drawings are described in detail below. The specific embodiment of the present invention is given in detail by the following examples and accompanying drawings.

Description of drawings

The accompanying drawings described here are used to provide a further understanding of the present invention and constitute a part of the application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention. In the attached picture:

Fig. 1 is a general structural block diagram of the integrated packaging structure of the present invention.

Explanation of symbols in the figure: 1. heat dissipation heat pipe, 2. CuW heat sink, 3. Si substrate, 4. gold wire, 5. metal bump, 6. LED chip, 7. silver reflective layer, 8. sapphire.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

Referring to Fig. 1, a power type LED integrated packaging structure includes a heat dissipation heat pipe 1, a CuW heat sink 2, a Si substrate 3, an LED chip 6 and a sapphire 8, and the heat dissipation heat pipe 1 is arranged at the bottom of the structure The CuW heat sink 2 is arranged above the heat dissipation heat pipe 1, the Si substrate 3 is arranged above the CuW heat sink 2, the LED chip 6 is arranged above the Si substrate 3, and the LED chip The top of 6 is provided with said sapphire 8.

Further, the LED chip 6 includes a P electrode and an N electrode, a metal bump 5 is respectively arranged under the P electrode and the N electrode, and the outer side of the Si substrate 3 and the LED chip 6 is connected by a gold wire. 4 connection, and a silver photoreflective layer 7 is set between the P electrode and the PN junction.

Working principle of the present invention:

In this structure, the light is taken out from the sapphire 8 substrate without taking out the current diffusion layer. Since the light is not taken from the current diffusion layer, the opaque current diffusion layer can be thickened, which increases the current density of the LED chip 6 . At the same time, this structure can also directly conduct the heat of the PN junction to the Si substrate 3 with high thermal conductivity and the CuW heat sink 2 through the metal bump 5, and the application of the heat pipe technology further improves the heat dissipation effect. Moreover, the silver reflective layer 7 between the PN junction and the P electrode eliminates the light blocking of the electrodes and leads, so this structure has optimal characteristics in terms of electricity, light, and heat.

The package structure adopts flip-chip technology, and the light emitting layer (light source) is closer to the package side, so it is easy to dissipate the heat of the LED chip 6 to the package side. In addition, the LED chip 6 is mounted by the flip-chip mounting method, and the light of the light-emitting layer is not shielded by the electrodes when it is emitted to the outside. Especially for products such as LEDs with sapphire substrates, where electrodes are only provided on one side of the LED chip, the effect is more obvious. The luminous efficiency of LEDs mounted by flip chips can be increased by 10% compared with those mounted by wire bonding.

The packaging structure chooses silicon wafer as the substrate of gallium nitride material, which has many advantages, such as high crystal quality, large size, low cost, easy processing, good electrical conductivity, thermal conductivity and stability, etc. The chip electrodes on the silicon substrate adopt a vertical contact method, so that the current can flow vertically, thus greatly increasing the LED light-emitting area, thereby improving the light-emitting efficiency of the LED. Because silicon is a good conductor of heat, the thermal conductivity of the device can be significantly improved, thereby prolonging the lifetime of the device.

The heat pipe heat dissipation is selected as the heat dissipation method of the integrated package structure to quickly dissipate the heat conducted by the chip. Heat pipe heat dissipation is not only simple in structure, but also has better thermal conductivity than copper rods, and has the reputation of "superconductor". A typical heat pipe is composed of a tube shell and a liquid-absorbing core. The working medium in the heat pipe absorbs heat in the evaporating section to generate phase-change steam, which flows to the condensation section with the pressure difference in the tube as the driving force, releases heat and condenses into a liquid, and is absorbed in the liquid-absorbing core. The capillary force in the liquid-absorbing core is the power to return to the evaporation section to realize circulation and heat dissipation. Compared with other heat dissipation methods, heat pipe technology has the characteristics of no additional power demand, mature technology, and high heat dissipation performance.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. a power-type LED integrated encapsulation structure, comprise heat radiation heat pipe (1), CuW is heat sink (2), Si substrate (3), LED chip (6) and sapphire (8), it is characterized in that, described heat radiation heat pipe (1) is arranged on the lowermost end of described structure, the top of described heat radiation heat pipe (1) is provided with described CuW heat sink (2), described CuW is heat sink (2), and top is provided with described Si substrate (3), described Si substrate (3) top is provided with described LED chip (6), the top of described LED chip (6) is provided with described sapphire (8).

2. power-type LED integrated encapsulation structure according to claim 1, it is characterized in that, described LED chip (6) comprises P electrode and N electrode, the below of described P electrode and N electrode is respectively arranged with a metal salient point (5), and described Si substrate (3) is connected by gold thread (4) with the outside of described LED chip (6), is provided with the anti-layer of silver-colored light (7) between described P electrode and PN junction.