CN102185091B - Light-emitting diode device and manufacturing method thereof - Google Patents

Abstract

A light emitting diode device includes at least one LED chip and a circuit board. The LED chip has an N pole and a P pole, and an electrode layer is covered on the surface of the N pole and the P pole, wherein, the thickness of the electrode layer on the surface of the N pole and the P pole is the same. The upper surface of the circuit board is covered with an insulating layer, and the upper surface of the insulating layer is covered with a conductive layer. A metal layer is arranged on the upper surface of the conductive layer corresponding to the N pole of the LED chip. The height difference between the N pole and the P pole of the chip. The LED chip is flip-chip arranged on the circuit board, wherein the P pole of the LED chip is connected to the conductive layer through the electrode layer, and the N pole of the LED chip is connected to the conductive layer through the electrode layer and the metal layer. Compared with the prior art, a metal layer is provided on the upper surface of the circuit board corresponding to the N-pole region of the LED chip in the light-emitting device of the present invention, which simplifies the design and manufacturing process of the LED chip, and further improves the performance of the LED chip. .

Description

A light emitting diode device and its manufacturing method

technical field

The invention belongs to the field of manufacturing light-emitting devices, and relates to a light-emitting diode device and a manufacturing method thereof, in particular to a light-emitting diode device adopting COB chip packaging technology and a manufacturing method thereof.

Background technique

Light-emitting diode (LED) is a kind of lighting source with energy-saving and environmental protection characteristics, which combines high light efficiency, low energy consumption, low maintenance cost and other excellent performances. Theoretically, it is estimated that the luminous efficiency of LED lighting can reach or even exceed 10 times that of incandescent lamps and 2 times that of fluorescent lamps. At present, LEDs have been widely used in mobile phone backlights, LCD display backlights, architectural landscapes, instructions, special lighting, etc., and are increasingly expanding to general lighting, automotive lighting and other fields. As the power and luminous efficiency of LED lighting products increase, the choice of structure and materials will have a decisive impact on the performance and service life of LEDs. One of the structures of the LED is to flip-chip solder the LED chips on the substrate, which has the advantages of better reliability and heat dissipation than the traditional front-mount chip structure.

Please refer to FIG. 1 , which is an existing chip unit structure of a traditional flip-chip LED. The chip unit includes an LED chip 10 and a circuit board 20 . The LED chip 10 includes an N pole and a P pole, the surfaces of the N pole and the P pole are covered with an electrode layer 12 , and the surface of the electrode layer 12 is covered with a metal pad 14 . A conductive layer 22 is disposed on the upper surface of the circuit board 20 . The metal pad 14 of the LED chip 10 is connected to the conductive layer 22 on the circuit board 20 through bump solder balls 46 . Since the depth of the N pole etched by the electrode ICP is relatively large, there is a height difference between the N pole and the P pole of the LED chip 10. In order to make the connection between the LED chip 10 and the circuit board 20 stronger after flip-chip welding, It is necessary to increase the thickness of the metal pad 14 on the N pole so that the metal pads 14 on the N pole and the P pole are on the same plane. However, the process of increasing the thickness of the metal pad 14 on the LED chip 10 is relatively complicated, and may also adversely affect the performance of the LED chip 10 during the manufacturing process.

Please refer to FIG. 2 , which is a schematic cross-sectional view of an LED chip flip-chip packaging structure disclosed in US Patent Application Publication No. US7321161B2. The packaging structure includes an LED chip 10 , a substrate 60 , a bracket 30 and potting glue 40 . The LED chip 10 is flip-chip mounted on the substrate 60 , the substrate 60 is set on the support 30 , and the electrode 62 on the substrate 60 is connected to the support electrode 32 on the support 30 through the gold wire 50 . The encapsulant 18 encapsulates the chip in the bracket 30 . The heat sink 36 is disposed centrally below the bracket 30 . The entire bracket also needs to be connected with the aluminum substrate or the PCB circuit board before it can be made into a lighting fixture or a light emitting device. In this packaging structure, the chip can only be connected to the heat sink or the circuit board through the bracket, and the heat emitted by the chip is transmitted to the heat sink or the circuit board through the bracket, and the heat dissipation channel is long. In addition, the bracket and the gold wire connection occupy a certain packaging cost. The thermal stress of the potting glue during packaging can easily deform or even break the gold wire, thereby reducing the yield and reliability of the product. Since each chip needs to be packaged on a bracket, the light-emitting device that realizes multi-chip integration needs to be assembled on the circuit board again, and the process is cumbersome.

Contents of the invention

The object of the present invention is to overcome the shortcomings and deficiencies in the prior art, and provide a light-emitting diode light-emitting device with simple process and rapid heat dissipation.

At the same time, the invention also provides a manufacturing method of the light emitting diode device.

The present invention is achieved through the following technical solutions: a light emitting diode device, characterized in that it includes at least one LED chip and a circuit board. The LED chip has an N pole and a P pole, and an electrode layer is covered on the surface of the N pole and the P pole, wherein the thickness of the electrode layer on the surface of the N pole and the P pole is the same. The upper surface of the circuit board is covered with an insulating layer, the upper surface of the insulating layer is covered with a conductive layer, and a metal layer is arranged on the upper surface of the conductive layer corresponding to the N pole of the LED chip, and the thickness of the metal layer is the The height difference between the N pole and the P pole of the LED chip. The LED chip is flip-chip arranged on the circuit board, wherein the P pole of the LED chip is connected to the conductive layer through the electrode layer, and the N pole of the LED chip is connected to the conductive layer through the electrode layer and the metal layer.

A method for manufacturing a light-emitting device, characterized in that: comprising the following steps

Step S1: Manufacture the LED chip, grow an epitaxial wafer with multiple layers of gallium nitride on the sapphire substrate, and form a P pole and N pole, and then form an electrode layer on the surface of P pole and N pole;

Step S2: manufacturing a circuit board, covering the upper surface of the circuit board with an insulating layer, then covering the upper surface of the insulating layer with a conductive layer, and then forming a metal layer on the surface of the conductive layer;

Step S3: Flip-chip the LED chip on the circuit board, and connect the electrode layer corresponding to the P pole of the LED chip to the conductive layer on the circuit board, and connect the electrode layer corresponding to the N pole of the LED chip to the circuit board. Metal layer connections on the board.

Further, the step S2 also includes the step of: forming a dielectric layer on the surface of the conductive layer; before or after the step S3, it also includes the step of: arranging a reflective cup on the upper surface of the dielectric layer of the circuit board, and using The LED chip is located in the containing space of the reflective cup.

Further, the step S1 also includes the step of: forming a metal pad on the surface of the electrode layer; the step of the step S3 is replaced by: flipping the LED chip on the circuit board, and making the P pole of the LED chip correspond to the electrode layer It is connected to the metal pad on the circuit board, so that the electrode layer corresponding to the N pole of the LED chip is connected to the metal pad on the circuit board.

Compared with the prior art, a metal layer is provided on the upper surface of the circuit board corresponding to the N-pole region of the LED chip in the light-emitting device of the present invention, and there is no need to thicken the electrode layer or the metal layer at the corresponding position of the N-pole of the LED chip. The thickness of the welding pad is adapted to the thickness of the electrode layer of the P pole and the thickness of the metal welding pad, which simplifies the design and manufacturing process of the LED chip, and further improves the performance of the LED chip. In addition, the heat generated by the LED chip in the light-emitting device can be conducted to the conductive layer of the circuit board through the P pole and N pole of the LED and its electrode layer and metal pad. Compared with the traditional packaging structure, there is no need to use brackets, shortening The heat dissipation channel is improved, the heat dissipation capability is enhanced, and the reliability of the device is improved.

In order to have a clearer understanding of the present invention, the specific implementation manners of the present invention will be described below in conjunction with the accompanying drawings.

Description of drawings

FIG. 1 is an existing chip unit structure of a traditional flip-chip LED.

Fig. 2 is a schematic cross-sectional view of an LED chip flip-chip packaging structure disclosed in the US Patent Application Publication No. US7321161B2.

Fig. 3 is a schematic cross-sectional structure diagram of a light-emitting diode light-emitting device according to Embodiment 1 of the present invention.

Fig. 4 is a top view of a light emitting diode light emitting device according to Embodiment 2 of the present invention.

Detailed ways

Example 1:

Please refer to FIG. 3 , which is a schematic cross-sectional structure diagram of the LED light-emitting device according to Embodiment 1 of the present invention. The light emitting device includes an LED chip 100 , a circuit board 200 , a reflective cup 300 and a packaging lens 400 . The reflective cup 300 is arranged on the upper surface of the circuit board 200, the LED chip 100 is arranged in the accommodation space of the reflective cup 300 and is flip-chip arranged on the upper surface of the circuit board 200, and the packaging lens 400 is arranged on the upper surface of the reflective cup 300. The upper part seals the LED chip 100 in the containing space.

Specifically, the LED chip 100 has an N pole and a P pole, the surfaces of the N pole and the P pole are covered with an electrode layer 102 , and the surface of the electrode layer 102 is covered with a metal pad 104 . Wherein, the thicknesses of the electrode layer 102 and the metal pad 104 on the surface of the N pole and the P pole are basically the same.

The upper surface of the circuit board 200 is covered with an insulating layer 202′. A conductive layer 204 is covered on the upper surface of the insulating layer 202 , and the conductive layer 204 is used for electrically connecting the N pole and the P pole of the LED chip 100 . Therefore, a metal layer 206 is disposed on the upper surface of the conductive layer 204 corresponding to the N pole of the LED chip 100 , and the thickness of the metal layer 206 is equal to the height difference between the N pole and the P pole of the LED chip 100 . The LED chip 100 is flip-chip installed on the circuit board 200, wherein the P pole of the LED chip 100 is connected to the conductive layer 204 through the electrode layer 102 and the metal pad 104, and the N pole of the LED chip 100 is connected to the conductive layer 204 through the electrode layer 102. The metal pad 104 and the metal layer 206 are connected to the conductive layer 204 . In addition, a dielectric layer 208 is disposed on the upper surface of the conductive layer 204 , and the reflection cup 300 is disposed on the dielectric layer 208 .

The surface of the storage space of the reflective cup 300 is provided with a reflective layer 302 with high reflectivity. The material of the reflective layer can be silver, aluminum, nickel highly reflective metal, alloy or polyethylene bisphthalate (PET) and other polymer reflective materials.

The shape of the circuit board 200 may be a rectangle, a circle, a polygon or the like.

The conductive layer 204 on the circuit board 200 can be made of metals such as copper, aluminum, nickel or conductive materials such as organic polymers.

The material of the metal layer 206 on the upper surface of the circuit board 200 may be tin, gold, silver, nickel and other metals or alloys.

The material of the electrode layer 102 and the metal pad 104 on the LED chip 100 can be a single metal material such as lead, tin, gold, silver, nickel or copper, or a multilayer material or alloy composed of the above single metal material.

The specific manufacturing method of the light-emitting device in Example 1 of the present invention is described in detail below:

Step S1 : Manufacturing the LED chip 100 . Specifically, an epitaxial wafer with multiple layers of gallium nitride is grown on a sapphire substrate, and a P pole and an N pole are formed on the LED chip through a series of process steps such as photolithography, etching, metal layer deposition, and passivation layer protection. , and then sequentially form an electrode layer 102 and a metal pad 104 on the surfaces of the P pole and the N pole.

Step S2: Manufacturing the circuit board 200 . An insulating layer 202 is covered on the upper surface of the circuit board 200 . Then a conductive layer 204 is covered on the upper surface of the insulating layer 202 . Next, a metal layer 206 is formed on the surface of the conductive layer 204. Specifically, the metal layer 206 is completed by a surface immersion gold process. A dielectric layer 208 is then formed on the surface of the conductive layer 204 .

Step S3: Flip-chip the LED chip 100 on the circuit board 200, and connect the metal pad 104 corresponding to the P pole of the LED chip 100 to the conductive layer 204 on the circuit board 200, so that the N pole of the LED chip 100 The corresponding metal pads 104 are connected to the metal layer 206 on the circuit board 200 . Specific methods can be used, such as reflow soldering, wave soldering, hot pressure welding, ultrasonic pressure welding, thermosonic welding, or a bonding process of heating and adding ultrasonic waves.

Step S4: disposing the reflective cup 300 on the upper surface of the dielectric layer 208 of the circuit board 200 , and making the LED chip 100 located in the containing space of the reflective cup 300 .

Wherein, the order of step 3 and step 4 can be interchanged.

Compared with the prior art, a metal layer is provided on the upper surface of the circuit board corresponding to the N-pole region of the LED chip in the light-emitting device of the present invention, and there is no need to thicken the electrode layer or the metal layer at the corresponding position of the N-pole of the LED chip. The thickness of the welding pad is adapted to the thickness of the electrode layer of the P pole and the thickness of the metal welding pad, which simplifies the design and manufacturing process of the LED chip, and further improves the performance of the LED chip. In addition, the heat generated by the LED chip in the light-emitting device can be conducted to the conductive layer of the circuit board through the P pole and N pole of the LED and its electrode layer and metal pad. Compared with the traditional packaging structure, there is no need to use brackets, shortening The heat dissipation channel is improved, the heat dissipation capability is enhanced, and the reliability of the device is improved. And, the LED chip is directly flip-chip welded on the circuit board, and gold wires are not needed during packaging, which improves device reliability, saves materials such as brackets and gold wires, and reduces costs.

Example 2:

Please refer to FIG. 4 , which is a top view of the LED light-emitting device according to Embodiment 2 of the present invention. It shows a circuit structure in which a plurality of independent LED chips 100 are simultaneously arranged on the same circuit board 200 to form a parallel connection. The multiple independent LED chips 100 realize their different electrical connections through the wiring design of the conductive layer 204 on the circuit board 200 . Wherein, the circuit board 200 is an aluminum substrate.

At the same time, the structure of the light-emitting device in the second embodiment can also be formed first, and then divided into a plurality of independent LED light-emitting device units as shown in the first embodiment by cutting.

The processing of the circuit board in this embodiment is simple, and it is easy to realize the integration, modularization and mass production of multiple LED chips.

The present invention can also have various embodiments, for example, an LED chip group composed of a plurality of LED chips can be arranged in a reflective cup to replace the single LED chip in the above-mentioned embodiments.

The present invention is not limited to the above-mentioned embodiments, if the various changes or deformations of the present invention do not depart from the spirit and scope of the present invention, if these changes and deformations belong to the claims of the present invention and the equivalent technical scope, then the present invention is also It is intended that such modifications and variations are included.

Claims (10)

1. a LED device, is characterized in that: comprise

---at least one LED chip, this LED chip have a N utmost point and a P utmost point, have the certain altitude drop between the described N utmost point and the P utmost point, and at surface coverage one electrode layer of this N utmost point and the P utmost point, wherein, this N utmost point and the P extremely thickness of the electrode layer on surface are identical;

---circuit board, the upper surface of this circuit board covers an insulating barrier, the upper surface of this insulating barrier covers a conductive layer, at this conductive layer, the upper surface in the zone of the N utmost point that should LED chip is provided with a metal level, and the thickness of this metal level is the N utmost point of this LED chip and the difference in height between the P utmost point;

This LED chip upside-down mounting is arranged on the upper of this circuit board, and wherein, the P utmost point of this LED chip is connected with conductive layer by electrode layer, and the N utmost point of this LED chip is connected with conductive layer with metal level by electrode layer.

2. LED device according to claim 1, it is characterized in that: also comprise a reflector, the surface of the receiving space of this reflector is provided with a reflector, the upper surface of the conductive layer of this circuit board also arranges a dielectric layer, this reflector is arranged on this dielectric layer, and makes LED chip be positioned at the receiving space of this reflector.

3. LED device according to claim 2, it is characterized in that: further comprise a package lens, its top that is arranged on this reflector is sealed in this LED chip in the receiving space of reflector.

4. LED device according to claim 1, it is characterized in that: this LED chip also comprises metal pad, it covers the surface of the electrode layer of the N utmost point and the P utmost point, the P utmost point of this LED chip is connected with conductive layer with metal pad by electrode layer, and the N utmost point of this LED chip is connected with conductive layer by electrode layer, metal pad and metal level.

5. LED device according to claim 1, it is characterized in that: the material of this metal level is the single metal material of tin, gold, silver, nickel or copper, or the multilayer material or the alloy that are comprised of above-mentioned single metal material.

6. LED device according to claim 1, it is characterized in that: the material of this conductive layer is copper, aluminium, nickel metal or organic polymer electric conducting material.

7. LED device according to claim 4 is characterized in that: the electrode layer on this LED chip and the material of metal pad are lead, tin, gold, silver, nickel or copper single metal material or the multilayer material or the alloy that are comprised of above-mentioned single metal material.

8. the manufacture method of a LED device, is characterized in that: comprise the steps

Step S1: make LED chip, the extension disk that the nitride multilayer gallium is arranged at Grown on Sapphire Substrates, sequence of process steps through photoetching, etching, metal level deposition and passivation layer protection, form the P utmost point and the N utmost point on LED chip, has the certain altitude drop between the described N utmost point and the P utmost point, then form electrode layer on the surface of the P utmost point and the N utmost point, this N utmost point and the P extremely thickness of the electrode layer on surface are identical;

Step S2: make circuit board, upper surface at circuit board covers an insulating barrier, then the upper surface at this insulating barrier covers a conductive layer, then forms a metal level on the surface of this conductive layer, and the thickness of this metal level is the N utmost point of this LED chip and the difference in height between the P utmost point;

Step S3: on this circuit board, and the extremely corresponding electrode layer of the P that makes this LED chip is connected with conductive layer on this circuit board with the LED chip upside-down mounting, and the N that makes this LED chip extremely electrode layer of correspondence is connected with metal level on this circuit board.

9. manufacture method according to claim 8, it is characterized in that: this step S2 also comprises step: the surface at this conductive layer forms a dielectric layer; Also comprised step before or after this step S3: a reflector is arranged on the dielectric layer upper surface of this circuit board, and makes this LED chip be positioned at the receiving space of this reflector.

10. manufacture method according to claim 8, it is characterized in that: this step S1 also comprises step: form metal pad in this electrode layer surface; The step of this step S3 replaces with: with the LED chip upside-down mounting on this circuit board, and the extremely corresponding electrode layer of the P that makes this LED chip is connected with metal pad on this circuit board, and the N that makes this LED chip extremely electrode layer of correspondence is connected with metal pad on this circuit board.

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