CN111906440A - Preparation method of display screen module - Google Patents

Abstract

The invention provides a preparation method of a display screen module, which comprises the following steps: 1) providing a substrate, wherein the surface of the substrate is provided with an electrode; 2) providing an LED chip and a transfer plate, and adhering the LED chip on the transfer plate; 3) aligning and attaching the electrodes of the LED chip on the transfer plate and the electrodes on the substrate; 4) and welding the substrate and the LED chip under a protective atmosphere. According to the invention, through improving the welding bonding process, the LED chip is transferred by the transfer plate at one time, the protective atmosphere is provided in the welding process, and the novel welding method is adopted, so that the use amount of the solder paste in the welding process can be effectively reduced, the yield can be improved, the cost can be saved, and the working procedures can be reduced. The invention has higher production and manufacturing efficiency and lower production cost, and has wide application prospect in the field of display screen manufacturing and designing.

Description

Preparation method of display module

technical field

The invention relates to a display screen design and manufacturing field, in particular to a preparation method of a display screen module.

Background technique

With the improvement of people's material living standards and the development of science and technology, higher requirements are put forward in display applications, such as high resolution, high contrast, and low power consumption. The defects of traditional display products make it gradually replaced by LED full-color display. The continuous iterative development of LED display product technology has become the first choice for indoor and outdoor large-screen displays, such as command centers, outdoor advertising screens, conference centers and other occasions.

Existing display technologies such as LCD and OLED cannot meet the needs of larger screen display, so Mini LED display came into being. Mini LED display needs to produce modules of different sizes first, assemble the modules into modules, and then assemble the modules into large screens of different sizes. A huge number of LED chips are arranged and welded on each module.

The COB (chip on board) method can be used to make a higher-precision display module. The COB method is to flip the RGB chip on the substrate, and then use a stamping method to form a film on the surface of the substrate to protect the module. effect. However, at present, the yield rate of display modules is generally not high. One of the main reasons is that there is a bottleneck in the die-bonding process, which causes the LED chips to be soldered, de-soldered, and offset. The need for multiple repairs seriously affects production efficiency. Therefore, developing a stable and efficient die-bonding process is an effective way to improve the production efficiency and production efficiency of display modules.

SUMMARY OF THE INVENTION

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a method for preparing a display screen module, which is used to solve the problem that the display screen module in the prior art is caused by virtual welding and de-soldering during the welding process. The problem of low production yield.

In order to achieve the above purpose and other related purposes, the present invention provides a preparation method of a display screen module, the preparation method includes the steps of: 1) providing an LED chip and a transfer plate, and fixing the LED chip on the transfer plate; 2) providing a substrate with electrodes on the surface of the substrate; aligning the electrodes of the LED chips on the transfer plate with the electrodes on the substrate; 3) under the action of a protective atmosphere and pressure, the The electrodes of the substrate are connected integrally with the electrodes of the LED chip by welding.

Optionally, step 1) includes the steps of: 1-1) forming a sticky material on the transfer plate, wherein the method for forming the sticky material includes one of coating glue and sticking double-sided tape; 1 -2) Transfer the LED chips to the transfer board, wherein the transfer method includes one of pick-and-place transfer and top-pin alignment transfer.

Optionally, the pressure generated by the electrodes of the LED chip and the electrodes on the substrate includes one of the transfer plate's own gravity or externally applied pressure, and the protective atmosphere includes one of an inert gas atmosphere and a vacuum atmosphere.

Optionally, step 3) includes the steps of: 3-1) providing a die-bonding cavity, the top of the die-bonding cavity has a laser welding window, the bottom of the die-bonding cavity has a heat soaking plate, and the die-bonding cavity is further It has an air inlet and an air outlet; 3-2) Place the substrate on the vapor chamber, introduce protective gas from the air inlet, and remove the protective gas in the die-bonding cavity from the 3-3) Use a laser to perform laser welding on the electrodes of the substrate and the electrodes of the LED chips fixed on the transfer board.

Optionally, in step 3-2), the protective gas includes an inert gas, and the inert gas includes one or more of nitrogen, helium, and argon, and the protective gas is used to reduce the Oxygen content to reduce metal oxidation reactions due to increased temperature.

Optionally, step 3) includes the step of: 3-1) providing a die-bonding cavity, the top of the die-bonding cavity has a laser welding window, the bottom of the die-bonding cavity has a soaking plate, the die-bonding cavity and the Vacuum system connection; 3-2) Place the substrate on the soaking plate, and use a laser to laser weld the electrodes of the substrate and the electrodes of the LED chips fixed on the transfer plate after vacuuming.

Optionally, the temperature of the soaking plate in step 3-1) can be adjusted, and the control range is between 0 and 400°C; the material of the soaking plate includes copper, iron, aluminum, and any two or more of the above. One of the alloys formed.

Optionally, the laser in step 3-3) includes one of a gas laser, a solid-state laser and a semiconductor laser.

Optionally, step 3) includes the steps of: 3-1) providing a reflow soldering furnace, and a protective gas is introduced into the reflow soldering furnace to reduce the oxygen content of the reflow soldering furnace; 3-2) the substrate It is placed in the reflow oven for reflow soldering, and during the reflow soldering process, pressure is continuously applied to the transfer plate until the reflow soldering is completed.

Optionally, step 3-2) by placing a weight press on the transfer plate to apply pressure on the transfer plate, or: by adding a covering pressure on the transfer plate that moves with the transfer plate device to continuously apply pressure to the transfer plate from top to bottom until the reflow soldering is completed.

As mentioned above, the preparation method of the display screen module of the present invention has the following beneficial effects:

The preparation method of the display screen module of the present invention can effectively improve the yield rate and save the cost and reduce the process. The invention has higher production efficiency and lower production cost, and has wide application prospects in the field of display screen manufacturing and design.

Description of drawings

1 to 8 are schematic structural diagrams of each step of a method for fabricating a display screen module according to an embodiment of the present invention.

Component label description

10 Substrates

101 First electrode

102 Second electrode

20 Transfer plate

30 LED chips

301 The first chip electrode

302 Second chip electrode

40 Lasers

50 Die Cavity

501 Vapor Chamber

502 Air intake

503 Air outlet

60 Reflow Oven

601 Overburden

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

When describing the embodiments of the present invention in detail, for the convenience of explanation, the cross-sectional views showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the protection scope of the present invention. In addition, the three-dimensional spatial dimensions of length, width and depth should be included in the actual production.

For convenience of description, spatially relative terms such as "below," "below," "below," "below," "above," "on," etc. may be used herein to describe an element shown in the figures or The relationship of a feature to other components or features. It will be understood that these spatially relative terms are intended to encompass other directions of the device in use or operation than those depicted in the figures. In addition, when a layer is referred to as being 'between' two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present.

In the context of this application, descriptions of structures where a first feature is "on" a second feature can include embodiments in which the first and second features are formed in direct contact, and can also include further features formed over the first and second features. Embodiments between the second features such that the first and second features may not be in direct contact.

It should be noted that the diagrams provided in this embodiment are only to illustrate the basic concept of the present invention in a schematic way, so the diagrams only show the components related to the present invention rather than the number, shape and the number of components in the actual implementation. For dimension drawing, the type, quantity and proportion of each component can be changed at will in actual implementation, and the component layout may also be more complicated.

Example 1

As shown in FIG. 1 to FIG. 7 , this embodiment provides a method for preparing a display screen module, and the preparation method includes the following steps:

As shown in FIG. 1 to FIG. 2 , wherein, FIG. 2 is a schematic cross-sectional structure diagram at AA' in FIG. 1 . First, step 1) is performed to provide an LED chip 30 and a transfer board 20 , and the LED chip 30 is adhered on the transfer plate 20 .

As an example, the transfer plate 20 is selected as a transparent plate through which the laser light can pass. In this embodiment, the transfer plate 20 is selected as a glass plate. On the one hand, the glass plate can provide a flat transfer for the LED chips 30 . On the other hand, the glass plate has good high temperature resistance and low thermal expansion coefficient, which can greatly improve the process stability; at the same time, the glass plate can effectively pass through the laser, so as to facilitate the subsequent laser welding process conduct.

Specifically, step 1) includes the steps:

1-1) forming a sticky material on the transfer plate 20, wherein the method for forming the sticky material includes one of coating glue and sticking double-sided tape;

1-2) Transfer the LED chips 30 to the transfer board 20 in an array arrangement, wherein the transfer method includes one of pick-and-place transfer and top-pin alignment transfer.

As shown in FIG. 3 to FIG. 6 , wherein FIG. 6 is a schematic diagram of the cross-sectional structure at AA' in FIG. 5 , then step 2) is performed to provide a substrate 10 with electrodes on the surface of the substrate 10 ; The electrodes of the LED chips 30 on the transfer plate 20 are aligned and bonded to the electrodes on the substrate 10 .

As shown in FIG. 3 and FIG. 4 , wherein FIG. 4 is a schematic cross-sectional structure diagram at AA' in FIG. 3 , the substrate 10 includes a PCB substrate (including FR4, BT, FR4+ BT-like, BT-like or FPC) Or a glass substrate, in this embodiment, the substrate 10 is a PCB substrate.

The substrate 10 includes electrode pairs arranged in an array, and each electrode pair includes a first electrode 101 and a second electrode 102 . The first electrode 101 is a positive electrode or a negative electrode, the second electrode 102 is a negative electrode or a positive electrode, and the first electrode 101 and the second electrode 102 have opposite polarities. The first electrode 101 and the second electrode 102 include one of gold, copper, tin, and silver. In this embodiment, the first electrode 101 and the second electrode 102 are tin electrodes.

Specifically, the first electrodes 101 on the substrate 10 and the first chip electrodes 301 of the LED chips 30 are matched and bonded, and the second electrodes 102 on the substrate 10 are matched and bonded with the second chip electrodes 302 of the LED chips 30 combine.

As an example, the first electrode 101 and the second electrode 102 are Sn electrodes.

As shown in FIG. 7 , step 3) is finally performed. Under the action of protective atmosphere and pressure, the substrate 10 and the LED chip 30 are welded, so that the electrodes of the substrate 10 and the electrodes of the LED chip 30 are welded. Welded connection.

For example, the welding method includes one of laser welding and reflow welding, and the protective atmosphere includes one of an inert gas atmosphere and a vacuum atmosphere.

In the present embodiment, step 3) comprises the steps:

3-1) Provide a die-bonding cavity 50, the top of the die-bonding cavity 50 has a laser welding window, the bottom of the die-bonding cavity 50 has a soaking plate 501, and the die-bonding cavity 50 also has an air inlet 502 with air outlet 503. The laser welding window may be formed of a transparent material, such as glass, to ensure that the die-bonding cavity 50 is in a sealed state.

The temperature of the soaking plate 501 can be adjusted, and the temperature of the soaking plate 501 can be controlled to a fixed value, so as to reduce the influence of process stability due to temperature changes, wherein the temperature adjustment range can be between 0 and 400°C; The soaking plate can reduce the laser energy required for welding and the specification of the laser; the material of the soaking plate 501 includes one of copper, iron, aluminum and any two or more of the above alloys. In this embodiment, the material of the vapor chamber 501 is copper.

3-2) Place the substrate 10 on the vapor chamber 501 , introduce a protective gas from the gas inlet 502 , and discharge the protective gas in the die-bonding cavity 50 from the gas outlet 503 .

Specifically, in step 3-2), the protective gas includes an inert gas, and the inert gas includes one or more of nitrogen, helium, and argon, and the protective gas is used to reduce the Oxygen content to reduce metal oxidation reactions due to increased temperature. Preferably, the protective gas reduces the oxygen content of the solid crystal cavity 50 to less than 500 ppm, which can greatly reduce the metal oxidation reaction caused by the temperature increase.

3-3) Use the laser 40 to perform laser welding on the substrate 10 and the LED chip 30 from a laser welding window.

For example, the laser 40 includes one of a gas laser, a solid-state laser and a semiconductor laser. In this embodiment, the laser 40 is an infrared laser. The laser 40 is located above the laser welding window, and the LED chips 30 are sequentially laser welded by the movement of the substrate 10 or the movement of the laser 40 .

In the above process, the transfer plate 20 remains on the LED chip 30, and can exert a certain pressure on the LED chip 30 by its own gravity during the laser welding process, so as to facilitate the strength of the laser welding and stability.

Since the oxygen content in the die-bonding cavity 50 is relatively low, oxidation of the electrodes on the chip and the substrate is avoided, the yield can be effectively improved, the cost can be saved, and the process can be reduced.

Example 2

As shown in FIG. 1 to FIG. 7 , this embodiment provides a method for preparing a display screen module, the basic steps of which are the same as those in Embodiment 1, and the difference from Embodiment 1 is that step 3) includes the steps:

Step 3-1), provide a die-bonding cavity 50, the top of the die-bonding cavity 50 has a laser welding window, and the bottom of the die-bonding cavity 50 has a soaking plate 501, and the die-bonding cavity 50 is connected to a vacuum system ;

Step 3-2), place the substrate 10 on the soaking plate 501, and use the laser 40 to perform laser welding on the substrate 10 and the LED chip 30 from the laser welding window after vacuuming. After that, the solid crystal cavity 50 is in a low oxygen-containing atmosphere, and the oxygen content is lower than 500 ppm.

The die-bonding chamber 50 in this embodiment adopts the setting of a vacuum chamber, which can save the use of inert gas, and can further reduce the oxygen content in the die-bonding chamber 50 .

Example 3

As shown in FIG. 1 to FIG. 8 , this embodiment provides a method for preparing a display screen module, the basic steps of which are the same as those in Embodiment 1, and the difference from Embodiment 1 is that step 3) includes the following steps:

Step 3-1) A reflow soldering furnace 60 is provided, and a protective gas is introduced into the reflow soldering furnace to reduce the oxygen content of the reflow soldering furnace 60 . The protective gas includes an inert gas, and the inert gas includes one or more of nitrogen, helium, and argon. high metal oxidation reaction. Preferably, the protective gas reduces the oxygen content of the reflow oven 60 to below 500 ppm, which can greatly reduce the metal oxidation reaction caused by the temperature increase. The temperature control range of the reflow oven 60 is 0-400°C.

3-2) The substrate 10 is placed in the reflow oven 60 for reflow soldering. During the reflow soldering process, pressure is continuously applied to the transfer board 20 until the reflow soldering is completed.

In a specific implementation process, a weight can be placed on the transfer plate 20 to exert pressure on the transfer plate 20. The weight can be a square block whose bottom size is the same as that of the transfer plate. 20 consistent.

In another specific implementation process, a pressing device 601 that moves with the transfer plate 20 can be added on the transfer plate 20 to continuously apply pressure to the transfer plate 20 from top to bottom until the Reflow soldering is complete. For example, the cladding device 601 has a cladding plate, and the bottom dimension of the cladding plate is the same as that of the transfer plate 20 , as shown in FIG. 8 .

As mentioned above, the preparation method of the display screen module of the present invention has the following beneficial effects:

The manufacturing method of the display screen module of the present invention can effectively improve the yield by improving the welding and bonding process, including using the transfer plate 20 to transfer the LED chip 30 at one time, providing a protective atmosphere during the welding process, and a novel welding method. , save costs and reduce processes. The invention has higher production efficiency and lower production cost, and has wide application prospects in the field of display screen manufacturing and design.

Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can make modifications or changes to the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in the present invention should still be covered by the claims of the present invention.

Claims (10)

1. A preparation method of a display screen module is characterized by comprising the following steps:

1) providing an LED chip and a transfer plate, and fixing the LED chip on the transfer plate;

2) providing a substrate, wherein the surface of the substrate is provided with an electrode; aligning and attaching the electrodes of the LED chips on the transfer plate with the electrodes on the substrate;

3) and under the action of protective atmosphere and pressure, the electrode of the substrate and the electrode of the LED chip are welded and connected into a whole.

2. The method of manufacturing a display screen module according to claim 1, wherein: the step 1) comprises the following steps:

1-1) forming an adhesive material on the transfer plate, wherein the method of forming the adhesive material comprises one of coating glue and adhering double-sided adhesive;

1-2) transferring the LED chip to the transfer plate, wherein the transferring method comprises one of pick-and-place transfer and thimble alignment transfer.

3. The method of manufacturing a display screen module according to claim 1, wherein: the pressure generated by the electrodes of the LED chip and the electrodes on the substrate comprises one of the self gravity of the transfer plate or the externally applied pressure, and the protective atmosphere comprises one of inert gas atmosphere and vacuum atmosphere.

4. The method of manufacturing a display screen module according to claim 1, wherein: the step 3) comprises the following steps:

3-1) providing a die bonding cavity, wherein the top of the die bonding cavity is provided with a laser welding window, the bottom of the die bonding cavity is provided with a soaking plate, and the die bonding cavity is also provided with an air inlet and an air outlet;

3-2) placing the substrate on the soaking plate, introducing protective gas from the gas inlet, and discharging the protective gas in the die bonding cavity from the gas outlet;

3-3) carrying out laser welding on the electrode of the substrate and the electrode of the LED chip fixed on the transfer plate by adopting a laser.

5. The method of manufacturing a display screen module according to claim 4, wherein: and 3-2) the protective gas comprises an inert gas, the inert gas comprises one or more of nitrogen, helium and argon, and the protective gas is used for reducing the oxygen content of the die bonding cavity so as to reduce the metal oxidation reaction caused by the temperature rise.

6. The method of manufacturing a display screen module according to claim 1, wherein: the step 3) comprises the following steps:

3-1) providing a die bonding cavity, wherein the top of the die bonding cavity is provided with a laser welding window, the bottom of the die bonding cavity is provided with a soaking plate, and the die bonding cavity is connected with a vacuum system;

and 3-2) placing the substrate on the soaking plate, and performing laser welding on the electrode of the substrate and the electrode of the LED chip fixed on the transfer plate by using a laser after vacuumizing.

7. The method of manufacturing a display screen module according to claim 4 or 6, wherein: the temperature of the soaking plate in the step 3-1) can be regulated and controlled, and the regulation and control range is between 0 and 400 ℃; the soaking plate is made of one of copper, iron, aluminum and alloy formed by any two or more of the above materials.

8. The method of manufacturing a display screen module according to claim 4 or 6, wherein: and 3-3) the laser comprises one of a gas laser, a solid laser and a semiconductor laser.

9. The method of manufacturing a display screen module according to claim 1, wherein: the step 3) comprises the following steps:

3-1) providing a reflow oven, and introducing protective gas into the reflow oven to reduce the oxygen content of the reflow oven;

3-2) placing the substrate in the reflow soldering furnace for reflow soldering, and continuously applying pressure on the transfer plate in the reflow soldering process until the reflow soldering is completed.

10. The method of manufacturing a display screen module according to claim 9, wherein: step 3-2) applying pressure on the transfer plate by placing a weight on the transfer plate, or: and continuously applying pressure to the transfer plate from top to bottom by adding a pressure applicator on the transfer plate, wherein the pressure applicator moves along with the transfer plate until the reflow soldering is completed.

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