CN203574006U - LED light source - Google Patents

Abstract

The utility model discloses an LED light source, which comprises a PCB board and a horizontal LED chip. The PCB board includes a board body, a gold track arranged on the board body, and a solder resist coating covering the gold track. The above solder resist coating is provided with a through hole corresponding to the PN electrode of the LED chip at the crystal bonding position, and the PN electrode of the LED chip is above the through hole and through the conductive silver glue and the through hole. Goldenway fixed connection. At the same time, the utility model also discloses a LED light source manufacturing technology using a conventional horizontal LED chip, that is, the bottom of the LED chip is completely opened up without shielding, and the sapphire bottom of the LED chip does not need to be electroplated with a reflective layer, so that The light efficiency of PN junction light energy is higher, the PN junction is closer to the surface of PCB, and the heat conduction effect is better. At the same time, it means the transformation and upgrading of LED chip epitaxial wafers, which can relatively shorten the LED chip manufacturing process and reduce the cost.

Description

A kind of LED light source

technical field

The utility model relates to the technical field of LED preparation, in particular to an LED light source. the

Background technique

At present, the LED chip packaging industry is a huge industry, which has made a significant contribution to economic development and growth. At present, a large number of aluminum wire bonding packaging technologies are used in the industry. The crystal machine uses silver glue to fix the LED chip on the surface of the substrate, and then bakes and solidifies the silver glue through an oven, and then imports an automatic aluminum wire bonding machine to conduct the PN electrodes of the LED chip, and complete the welding according to the programmed procedure. The currently implemented crystal-bonding technology has been used for 30 years. The LED chips are all crystal-bonded with the bottom facing down and fixed in contact with silver glue. The PN pole on the top is connected to the PCB gold channel through aluminum wire or gold wire. the

There is also a gold wire bonding packaging technology. The gold wire bonding machine mainly adds high-voltage discharge burning balls. First, the gold balls are planted, and then the gold balls are connected to the substrate through ultrasonic waves, and the wire bonding process is completed. The price of the wire welding machine is relatively expensive. The same needs to be used with the automatic die bonding machine to complete the program from die bonding to wire bonding. Therefore, based on the above performance, it is necessary to execute more than two programs to complete the packaging process. The traditional The investment cost of LED chip packaging equipment is very high. the

At present, there is still a high-end flip-chip device that is also used in the packaging industry, called BGA (Ball Grid Aray) flip-chip technology, which is the CPU microprocessor ball planting flip-chip technology. Below the microprocessor, there are hundreds of terminals, the density is quite high, and it is an expensive device. It must first pass the ball planting technology, and a solder ball is implanted on each terminal, and it is through the high-end visual Welding and encapsulation of bit software cannot be operated by human eyes, so the equipment used is quite expensive. In addition, the current specification of flip-chip LED chips is several times the price of conventional chips. The key is that the PN electrodes of LED chips must be Heightening to the same height, and using high-purity AU pure gold material, mainly results in an increase in the cost of LED chips. the

At present, the industry is divided into two types of chip structures, horizontal and vertical. Vertical chips cannot be flip-chip at all, and only horizontal chips can be selected. The most common horizontal structure chips are LEDs with different heights of P poles and N poles. Chips, such as the LED chips mentioned in Chinese patent 201020602414.9, cannot be flipped according to this standard. This is also the reason why the LED chip packaging industry has stagnated for 30 years and has not made any progress. The encapsulation and quantification of LED chips and the cost reduction is a problem that needs to be solved urgently. the

Utility model content

The purpose of the utility model is to disclose an LED light source aiming at the technical defects existing in the prior art. the

The technical scheme adopted for realizing the purpose of this utility model is:

An LED light source includes a PCB board and a horizontal LED chip. The PCB board includes a board body, a gold track arranged on the board body, and a solder resist coating covering the gold track. The solder resist coating The layer is provided with a through hole corresponding to the PN electrode of the LED chip at the crystal bonding position, and the PN electrode of the LED chip is above the through hole and fixedly connected to the gold track at the through hole through conductive silver glue. the

The height of the P pole of the horizontal LED chip is greater than that of the N pole. the

The P pole and the N pole of the horizontal LED chip have the same height. the

Compared with the prior art, the beneficial effects of the utility model are:

The utility model realizes the flip-chip packaging technology of conventional horizontal LED chips, can adopt standard conventional horizontal LED chips, only needs to design matching chip size and use with the substrate, and can save aluminum wire or gold wire welding The wire bonding program of the wire machine greatly shortens the time required for the packaging process, and achieves a one-stop packaging process for a set of equipment, which really effectively improves the yield rate and reduces the actual management cost. the

At the same time, the utility model also discloses a LED light source manufacturing technology using a conventional horizontal LED chip, that is, the bottom of the LED chip is completely opened up without shielding, and the sapphire bottom of the LED chip does not need to be electroplated with a reflective layer, so that The light efficiency of PN junction light energy is higher, the PN junction is closer to the surface of PCB, and the heat conduction effect is better. At the same time, it means the transformation and upgrading of LED chip epitaxial wafers, which can relatively shorten the LED chip manufacturing process and reduce the cost. the

Description of drawings

Shown in Fig. 1 is the structural representation of PCB board of the present utility model;

Figure 2 is a schematic diagram of the state before solid crystal;

Figure 3 is a schematic diagram of the state of placing the LED chip behind the silver glue stack;

Figure 4 is a schematic diagram of the fixed structure. the

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is described in further detail. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model. the

As shown in Figures 1-4, a method for bonding LED chips of the present invention includes the following steps: 1) Set a cavity 4 that penetrates through the PCB insulating layer 3 at the bonding position of the PCB 1, such as a solder resist coating , this step is referred to as window opening, the dimples need to be arranged in pairs and each pair of dimples corresponds to the P pole and N pole of the LED chip respectively, that is, the diameter and position of the PN electrode of the LED chip are determined at the crystal bonding position The dispensing position of the silver glue, and then open a window there to form a hole through the insulating layer, so that the gold channel 2 of the PCB can be exposed to conduct electricity, and the shape and size of the cavity can be arbitrarily designed for different LED chips, just need to match the chip If the PN electrode is used to standardize the flow range of silver glue, it will not cause short circuit failure of the PN electrode of the chip. The principle is that it cannot cause short circuit or leakage problems. the

2) Inject the conductive silver glue 5 into the cavity. With the help of the liquid form of the conductive silver glue, when the conductive silver glue is dropped into the surface of the gold channel by the dispensing needle, due to the effect of surface tension, it will produce wire drawing and form a silver The shape of the pile is like a tiny pyramid or cone shape. The height of the silver glue pile is higher than the thickness of the window opening of the insulating layer. At this time, you can also refer to factors such as the current power setting of the LED chip, and the programming of the die-bonding machine The parameter determines the size of the silver pile area;

3) Place the 6PN electrode of the LED chip facing down on the corresponding crystal bonding position and set the P pole and N pole on the corresponding conductive silver glue drop; when the PN pole of the LED chip is covered on the silver glue stack , the liquid silver glue will fall under the gravity of the LED chip, and the PN electrode of the chip will touch the conductive silver glue. When the balance between the two sides of the PN pole of the chip is reached, it will stop falling. PCB golden way contact;

4) Bake the conductive silver glue to make it solidify and complete the chip solidification at the same time. After the silver glue is cured, it means that the LED chip has been connected to the gold channel of the PCB, and the LED performance can be tested by powering on. The temperature of the silver glue sintering is generally controlled At 150-170°C, the sintering time is about 2 hours, which can be adjusted according to the actual situation. Preferably, this step can be baked in a flat-plate heating tunnel, which can greatly shorten the curing time of the silver glue. The actual measurement procedure only takes 15 minutes to achieve curing, and the power-on test can be performed. the

Among them, the LED chip of the present utility model is a conventional LED chip, which is a single chip formed by splitting the epitaxial wafer of a sapphire-based conventional LED chip through laser cracking. The PN electrodes of the conventional LED chip are of different heights, generally extremely high It is only a few microns smaller than the N pole, so it cannot be used for ball planting and crystal bonding procedures, nor can it be applied to the existing flip-chip process. However, the utility model uses the dispensing needle of the automatic crystal bonding machine to make two silver chips at the window opening. The glue stack, with the help of the automatic adjustment of the liquid silver glue stack, the fixation and wiring of the LED chip are realized, that is, the PN electrode of the LED chip is conducted by the conductive silver stack and the gold channel of the PCB, that is, the LED chip with a conventional horizontal structure is used The flip chip program can be upgraded and applied, which reduces the cost of LED packaging and processing. At the same time, only the conventional die-bonding machine can be used to automate the flip chip process. Compared with the previous flip chip process, the wire bonding process is eliminated, which greatly reduces The flow of the packaging procedure is simplified, the manufacturing process is shortened, and the cost of equipment investment is reduced. At the same time, after the LED chip is solidified, it can be powered on for testing, and the yield rate is improved. The package can be completed in one stop. At the same time, after the LED chip is flipped, the bottom is completely open. No shading, 100% light-emitting area, no pad shading problem, PN junction has higher light emission efficiency, and at the same time, PN junction is closer to the PCB surface, and the thermal conductivity parameter of silver is greater than that of tin, realizing the heat conduction of PN junction of the utility model The effect is better than the ball planting technique. the

The LED chips used in the utility model can be raw materials for purchasing LED chips, because the original LED chip is packaged on a piece of blue film to protect the LED chip and fix it against static electricity. The turning of the film, that is, the first choice is to prepare a blank white film material, heat the blue film to a certain temperature through the expansion machine, cover a white film on the top of the LED chip, and apply pressure on the top to make the white film and the chip tightly adhere At this time, the lower blue film is hot, and the upper white film is cold, so that the LED chip is easier to separate from the blue film, and at the same time, the PN electrode turns to the direction of the white film, and the LED chip is transferred to the white film, and the PN electrode can be produced. In the direction of shifting, each blue film needs to be flipped once. Of course, the flipping step can also be turned by a selection machine, that is, the utility model does not limit the flipping method of the LED chip. Of course, direct purchase or customized PN pole facing down can also be used. For LED chip products, when the fixing machine is working, it is preferable to use the expansion machine to make the chips apart, which is suitable for the suction nozzle operation of the die bonding machine. the

At the same time, the utility model also discloses an LED light source, which includes a PCB board and an LED chip. The PCB board includes a board body, a gold channel arranged on the board body, and an insulating layer covering the gold channel, such as A solder resist coating, the solder resist coating is provided with a window-opening through hole corresponding to the PN electrode of the LED chip at the crystal bonding position, and the PN electrode of the LED chip is above the through hole in parallel It is fixedly connected to the gold channel at the windowed through hole through conductive silver glue. Wherein, the P pole of the LED chip is higher than the N pole. Among them, the LED light source of the present invention can be applied to any form of lamps, such as strip light sources, bulb lamps, spotlights and other forms. the

The standard flip chip adopts the solid crystal co-firing procedure, that is, a solder ball is planted on the PN electrode of the LED chip, programmed through the visual alignment software, attached to the gold channel of the PCB, and insulating glue is used for solid crystal, and then passed At high temperature, the die-bonding glue and solder balls are co-fired and solidified at the same time to form a contact fixation on the PCB gold track. 

However, the flip chip bonding technology of the present utility model uses a general conventional horizontal LED chip, and a circular window is arranged in the bonding area of the PCB to expose the gold channel, and the other parts are all covered, and the chip is automatically bonded. The programming software of the machine sets two silver colloid stacks at the window opening. When the PN electrodes of the LED chip are aligned, the corresponding electrodes will fall on the silver colloid stacks, because the silver colloid is still in a liquid state and is subject to the gravity of the LED chip. The silver glue will drop down to the level and stop, and then enter the oven to bake and solidify, and then the crystal fixation procedure can be completed. This utility model adopts the procedure of first opening the window, then dropping the glue and then flipping it, which is the main core of the utility model. It is different from the past The ball planting technology procedures of different countries have great essential differences in steps, equipment used and cost. the

The above is only a preferred embodiment of the utility model, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the utility model, some improvements and modifications can also be made, these Improvement and retouching should also be regarded as the protection scope of the present utility model. the

Claims (3)

1. a LED light source, it is characterized in that, comprise pcb board and horizontal LED chip, described pcb board comprises plate body, be arranged on plate body Shang Jin road, cover the anti-welding coat on golden road, described anti-welding coat is provided with the through hole of answering with described LED chip PN electrode pair in die bond position, and the PN electrode of described LED chip and described through hole top is also fixedly connected with Jin road, through hole by conductive silver glue.

2. LED light source as claimed in claim 1, is characterized in that, the height of the P utmost point of described horizontal LED chip is greater than the N utmost point.

3. LED light source as claimed in claim 1, is characterized in that, the P utmost point of described horizontal LED chip and N utmost point double altitudes.

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