WO2014008773A1

WO2014008773A1 - Method of fabricating surface-mounted led module

Info

Publication number: WO2014008773A1
Application number: PCT/CN2013/074164
Authority: WO
Inventors: 廖泳; 吕宗宜
Original assignee: 厦门吉瓦特照明科技有限公司
Priority date: 2012-07-09
Filing date: 2013-04-12
Publication date: 2014-01-16
Also published as: CN102779923B; CN102779923A

Abstract

Disclosed is a method of fabricating a surface-mounted LED module, comprising the following steps: preparing, providing an LED chip (10) of a flip-chip structure, one side of the LED chip (10) having metal electrodes (13), and the surface pitch of the metal electrodes (13) being not smaller than 80 μm; arranging, placing a plurality of LΕD chips (10) in a strip, the metal electrodes (13) of the LED chip (10) being located at the bottom of a strip receiving space (23), and the light emitting surface (12) of the LED chip (10) being located at the opening of the receiving space (23); adhering, sucking the LED chip (10) from the strip using a vacuum suction cup (30), and placing the LED chip (10) on a solder pad of a substrate, so that the metal electrode (13) is opposite the solder pad, and the light emitting surface (12) of the LED chip (10) faces upwards; and fixing, correspondingly fixing and joining the solder pad and the metal electrode (13). By directly adopting a strip carrying manner for a flip-chip LED chip, the encapsulation of a single LED light source is avoided; the encapsulation material, encapsulation process time, and production line for a single LED light source are saved.

Description

Method for manufacturing chip type LED module

Technical field

The invention relates to a production method for manufacturing a chip type LED module.

Background technique

With the development of lighting LED technology, compared with the traditional incandescent lamp, halogen lamp type of illumination source, LED has obvious advantages of energy saving, reliability, longevity, and can gradually achieve the lighting performance of fluorescent lamps, such as light effect and display Color index, life aspect. Therefore, the global development of lighting LEDs is on the rise, and the annual output of LED light sources is gradually increasing.

Compared with traditional light sources, LED light sources have some obvious features. Usually, in terms of volume, LED light sources are in units of a single chip, with electrodes, phosphors, package structures, etc., with a small volume and With less luminous flux, if it is necessary to form a suitable lighting fixture, it is inevitable to use multiple LED light sources to form an array of modules. On the one hand, it can integrate volume, structure shape and uniform power supply, on the other hand, sufficient luminous flux must be achieved. These features are already prominent in general lighting and indoor lighting: a more common practice is to arrange a complete package of LED light sources on the substrate to be fixed and connected to form an LED module that can be illuminated as a whole, and then assembled into a complete module. Lighting. If the luminaire is large in shape and the luminous flux required for a single luminaire is high (such as 1000 lm or more), the number of single LED light sources must be very large, especially when using LED light sources packaged in medium and small power (such as 10 mil). Therefore, the manufacturing process of the entire module is very long, and it is necessary to complete the packaging of a single LED light source before soldering on the substrate to form a module.

In response to this problem, there is a type of COB (chip-on-board) technology, in which the chip is fixed on the substrate, and then the wire is connected, and finally the phosphor is coated and the protective glue is covered. This type of method eliminates the package of a single LED light source, but brings a new problem: after the LED chip is fixed on the substrate, it is always necessary to perform single wire bonding, powder coating, etc., taking into account the strength of the wire, its failure rate. Higher, the processing causes more hidden dangers. Moreover, the process time is too long and the quantity of materials is large, so the material cost and time cost of manufacturing are difficult to reduce.

Therefore, in the large-scale production of LED modules, it is always difficult to avoid the problem that the package structure brings too high cost and the process flow caused by complicated materials is too long and the reliability is not high.

Summary of the invention

The main object of the present invention is to provide a method for manufacturing a chip-type LED module, which solves the problem of excessive material cost of the packaged material when the LED module is mass-produced, and another object is to solve the problem of large-scale pressing of the LED module. The time cost of the process time is too long during production; the other purpose is to solve the hidden danger of the single LED light source on the finished LED module without the high reliability of the processing technology:

A method for manufacturing a chip type LED module, comprising the following steps:

Preparation: providing a flip-chip structure of the LED chip, one side of the LED chip has a metal electrode, and the surface spacing of the metal electrode is not less than 80 μm;

Arranging a plurality of the LED chips in a braided strip, the metal electrodes of the LED chip are located at the bottom of the tape receiving space, and the light emitting surface of the LED chip is located at the opening of the receiving space;

Mounting: the LED chip is sucked out from the braid by a vacuum nozzle, and placed on a pad of a substrate; the metal electrode is opposite to the pad, and the light emitting surface of the LED chip faces upward; and

Fixed: The pad and the metal electrode are fixed and connected correspondingly.

As an improvement of the technical solution, it can be embodied in the following aspects:

In a preferred embodiment, the mounting step is occupied, the tape is placed on an automatically fed placement machine, and controlled to feed one by one.

In a preferred embodiment, in the mounting step, a solder paste is preliminarily disposed on the pad, and a metal electrode of the LED chip is temporarily fixed to the substrate by a surface tension of the solder paste.

In a preferred embodiment, a solder reflow machine is used to cure the solder paste between the metal electrode and the pad.

In a preferred embodiment, the reflow soldering machine includes the following processes:

Sending a plate: placing the already mounted substrate on a conveyor belt, the conveyor belt being controlled and traveling;

Preheating: volatilizing the auxiliary solvent in the solder paste;

Average temperature: activate the flux in the solder paste and evaporate excess water;

Reflow soldering: melting the solder paste to fill the area between the metal electrode and the pad and connecting the two;

Cooling: The temperature of the solder paste, metal electrode, and pad is lowered to a cooling temperature.

In a preferred embodiment, the pad has a plurality of pads on the substrate, and the solder paste is attached to the pad by screen printing.

In a preferred embodiment, after the fixing step is completed, the light emitting surface of the LED chip is covered with a fluorescent film, and the fluorescent film is in one-to-one correspondence with the LED chip, and is separately mounted.

In a preferred embodiment, after the fixing step is completed, the light emitting surface of the LED chip is covered with a fluorescent film, and the fluorescent film is in the form of a monolithic film covering the surface portion of the LED chip together with the substrate on which it is placed.

In a preferred embodiment, after the fixing step is completed, the light emitting surface of the LED chip is covered with a fluorescent film, and the fluorescent film is directly sprayed on the light emitting surface of the LED chip by liquid spraying, together with the same side thereof. The surface of the substrate.

In a preferred embodiment, the LED chip emits visible light and is in the range of 440-470 nm. It can also be used to emit ultraviolet light with a wavelength range of 240-355 nm.

In a preferred embodiment, in the mounting step, an auxiliary colloid having a bottom portion of the LED chip temporarily fixed to the surface of the substrate is disposed adjacent to the pad.

The beneficial effects brought by the invention are:

1. The flip chip LED chip is directly loaded by braiding, which avoids the packaging of a single LED light source, saves the packaging material and packaging process time of a single LED light source, and the production line;

2. The vacuum nozzle absorbs the light-emitting surface of the LED chip, and its geometric characteristics are consistent, and there is no leakage failure caused by irregular shape, and the patch has low failure rate and accurate positioning;

3. Tape-type LED chip, all the chip process can use the existing SMT equipment, no additional hardware investment, avoiding the cost and process time of the packaging line, and the mass production is easier to implement;

4. After the flip-chip structure of the LED chip is mounted on the substrate, it is easy to realize the stroke of the fluorescent film, and the whole coating method can be used to realize the phosphor coating in a large area, and the spraying device can not contact the LED chip, and the process time is short, and there is no The hidden dangers caused by the contact process.

DRAWINGS

The present invention is further described below in conjunction with the embodiments of the drawings:

1 is a side view of a flip chip structure LED chip 10 used in Embodiment 1 of the present invention;

2 is a view showing the form of the LED chip 10 in the braid 20 after receiving the LED chip tapping step of the embodiment;

Figure 3 is a plan view of the braid 20 of the embodiment;

Figure 4 is a state of the mounting step of the first embodiment;

Figure 5 is another state of the mounting step of the first embodiment;

Figure 6 is a plan view of the first embodiment after the fixing step is completed;

Figure 7 is a side view of the state shown in Figure 6;

Figure 8 is a state diagram of a powder coating step after the mounting step of the first embodiment;

Figure 9 is a state diagram of the second mounting step of the embodiment of the present invention;

Fig. 10 is a view showing the state of the powder coating step after the completion of the mounting step of the second embodiment.

detailed description

Embodiment 1:

As shown in FIG. 1, the LED chip 10 of the Flip-chip structure used in the present invention has a main body 10 as a semiconductor material portion and a lower and a negative metal electrode which is in ohmic contact with the main body 10, and is below the main body 10. In the plane of the metal electrodes 13, the distance G1 between the electrodes 13 is 80 μm; the LED chip of the flip-chip structure, the light-emitting surface 12 and the metal electrode 13 of the conductive portion are located on both sides of the body 10, and do not interfere with each other, and the luminous efficiency thereof is high. .

As shown in FIG. 2 and FIG. 3, the LED chips 10 are placed one by one in the braid 20, each LED chip occupies an accommodating space 23, and is independent of each other; and the metal electrode 13 of the LED chip 10 is located at the bottom of the accommodating space 23; The light exit surface 12 is located at the opening of the accommodating space. When the LED chip 13 is placed in the accommodating space, the protective film 21 is closed at the opening of the braid 20 to protect the accommodating space 23. The braid 20 has a positioning hole along its length direction, which facilitates the ratcheting mechanism of the braiding machine to grasp and drive its travel, and realize automatic feeding one by one. The tape of this embodiment is suitable for the placement machine of all the patch products, and has good versatility.

As shown in FIG. 4 and FIG. 5, the two states of the mounting steps are respectively performed; after the tape 20 is mounted on the automatic placement machine, the placement machine is loaded on the substrate 40 to be mounted; the vacuum nozzle 30 is extended. In the accommodating space, after touching the light-emitting surface 12 of the LED chip 10, the same position is sucked out, which is the suction state shown in FIG. 4; and then translated to the upper surface of the substrate 41, wherein the pad 41 is the final One-to-one correspondence with the metal electrodes 13 has a screen-printed solder paste 42 on the pad 41; the pad 41 gap G2 is also 80 μm. This is the patch state shown in FIG. After the state shown in Fig. 5, the metal electrode 13 and the pad 41 are temporarily fixed by the tension of the solder paste 42 itself, and are not randomly displaced due to air flow or shaking.

After that, the solder paste 42 passes through the following steps in the reflow soldering machine:

Sending board: placing the already mounted substrate 40 on the conveyor belt, and the conveyor belt is controlled and travels;

Preheating: volatilizing the auxiliary solvent in the solder paste 42;

Average temperature: activate the flux in the solder paste 42 and evaporate excess water;

Reflow soldering: molten solder paste 42 fills the area between the metal electrode 13 and the pad 41 and connects the two;

Cooling: The temperature of the solder paste 42, the metal electrode 13, and the pad 41 is lowered to the cooling temperature.

After the above process is completed, as shown in FIGS. 6 and 7, the LED chip 10 which has been mounted and fixed, the metal electrode 13 and the pad 41 have been fixed and kept in communication by the solid solder paste 42. The solder paste 42 has pulled the metal electrode 13 in alignment by its own tension before solidification. In this way, the LED chip 10 has been fixed on the substrate 40, and all the LED chips 10 on the substrate 40 are connected according to the line of the pad 41, and a complete module has been formed, which can be illuminated by being connected to the power source.

In this embodiment, the 455 nm blue LED chip 10 is used, and the entire module needs to realize white light output of 4000K color temperature. Therefore, the module must be coated with phosphor. In this embodiment, the liquid powder is sprayed directly to spray the phosphor. The light emitting surface of the LED chip 10, together with the substrate surface on the same side thereof. After proper baking, the surface of the light-emitting surface 12 of the LED chip 10 and the side surface thereof are provided with a fluorescent film 12, so that the LED chip 10 fixed on the entire substrate 40 can emit white light through the whole body to meet the requirements of high-light illumination. .

It can be seen that the flip chip LED chip 10 adopts the method of tape loading directly, and has obvious features, so that the manufacturing process of the whole LED module avoids the packaging of a single LED light source, and finally all the LED chips 10 can be removed without a single package. Fixed and connected to the substrate 40, saving the packaging material and packaging process time of the single LED light source, and the production line; Moreover, the placement machine of the vacuum nozzle 30 absorbs the light emitting surface of the LED chip 10, and the geometric characteristics thereof are consistent. Good sex, no irregularity caused by irregularities, For example, the uneven surface of the phosphor, so the patch failure rate is low, the positioning is accurate; in addition, when the tape type LED chip 10 is used, all the patch processes can use the existing SMT device without additional The input of hardware avoids the cost and process time of the package line, and the mass production is easy to realize. Finally, when the flip chip LED chip 10 is mounted on the substrate 40, the stroke of the fluorescent film is easily realized, and the whole spray can be used. The method of realizing phosphor coating on a large area, the spraying equipment can not touch the LED chip 10, the process time is short, and there is no hidden trouble caused by the contact process.

Embodiment 2:

9 and FIG. 10, two state diagrams of Embodiment 2 of the present invention:

The difference between the embodiment and the first embodiment is that, in the mounting step, the substrate 40 has an auxiliary colloid 45 between the pads 41. The auxiliary colloid 45 functions when the LED chip 10 is large in volume. It is difficult to temporarily fix the LED chip 10 to the substrate by the tension of the solder paste 42, and the auxiliary colloid 45 serves as a temporary component to make the LED chip 10 and the pad 41 relatively accurate and stable, and the posture deviation does not occur even after the reflow oven. .

Another difference is that after the fixing step of the LED chip 10 is completed, the light emitting surface of the LED chip 10 is covered with the fluorescent film 50. The fluorescent film is in the form of a monolithic film, which is separately formed, so that the appropriate pressure and bonding can be directly used. The fluorescent film 50 is entirely covered on the LED chip 10 together with the surface portion of the substrate 40. This method further shortens the molding time of the entire module, does not require spraying, and does not need to be baked for curing, so it is very fast. Process flow.

It can be seen that the direct bonding of the LED chip 10 to the substrate 40 by the placement machine has obvious convenience for coating the phosphor on a large area, so that the fluorescent film can be efficiently formed by various methods.

The above is only the preferred embodiment of the present invention, and thus the scope of the present invention is not limited thereto, that is, equivalent changes and modifications made in accordance with the scope of the invention and the contents of the specification should still be covered by the present invention. Within the scope.

Industrial applicability

The flip chip LED chip is directly loaded by the tape, which avoids the packaging of a single LED light source, saves the packaging material and packaging process time of a single LED light source, and the production line.

Claims

A manufacturing method of a chip type LED module, comprising: the following steps:

Preparation: providing a flip-chip structure of the LED chip, one side of the LED chip has a metal electrode, and the surface spacing of the metal electrode is not less than 80 μm;

Arranging a plurality of the LED chips in a braided strip, the metal electrodes of the LED chip are located at the bottom of the tape receiving space, and the light emitting surface of the LED chip is located at the opening of the receiving space;

Mounting: the LED chip is sucked out from the braid by a vacuum nozzle, and placed on a pad of a substrate; the metal electrode is opposite to the pad, and the light emitting surface of the LED chip faces upward; and

Fixed: The pad and the metal electrode are fixed and connected correspondingly.
The method for manufacturing a chip-type LED module according to claim 1, wherein the mounting step is occupied, the tape is placed on an automatic feeding device, and controlled by feeding one by one. .
The method of manufacturing a chip-type LED module according to claim 1, wherein in the mounting step, solder paste is preliminarily provided on the pad, and the metal electrode of the LED chip utilizes the The surface tension of the solder paste is temporarily fixed to the substrate.
The method of manufacturing a chip-type LED module according to claim 1, wherein the solder paste between the metal electrode and the pad is cured by a reflow soldering machine in the fixing step.
The method of manufacturing a chip-type LED module according to claim 4, wherein the reflow soldering machine comprises the following processes:

Sending a plate: placing the already mounted substrate on a conveyor belt, the conveyor belt being controlled and traveling;

Preheating: volatilizing the auxiliary solvent in the solder paste;

Average temperature: activate the flux in the solder paste and evaporate excess water;

Reflow soldering: melting the solder paste to fill the area between the metal electrode and the pad and connecting the two;

Cooling: The temperature of the solder paste, metal electrode, and pad is lowered to a cooling temperature.
The method for manufacturing a chip-type LED module according to any one of claims 1 to 5, wherein the pad has a plurality of the substrate, and the solder paste is screen printed. The method is attached to the pad.
The method for manufacturing a chip-type LED module according to claim 6, wherein after the fixing step is completed, the light-emitting surface of the LED chip is covered with a fluorescent film, the fluorescent film and the LED chip. One-to-one correspondence, mounted separately.
The method for manufacturing a chip-type LED module according to claim 6, wherein after the fixing step is completed, the light-emitting surface of the LED chip is covered with a fluorescent film, and the fluorescent film is an integral film. The form covers the surface portion of the LED chip together with the substrate on which it is placed.
The method for manufacturing a chip-type LED module according to claim 6, wherein after the fixing step is completed, the light-emitting surface of the LED chip is covered with a fluorescent film, and the fluorescent film is sprayed by liquid. Sprayed directly onto the light exit surface of the LED chip, along with the substrate surface on the same side thereof.
The method for manufacturing a chip-type LED module according to claim 6, wherein the LED chip emits visible light and is in the range of 440-470 nm.
The method for manufacturing a chip-type LED module according to claim 6, wherein the LED chip emits ultraviolet light and has a wavelength range of 240-355 nm.
The method for manufacturing a chip-type LED module according to claim 6, wherein in the mounting step, the pad is provided with a surface for temporarily fixing the bottom of the LED chip to the surface of the substrate. Auxiliary colloid.