An LED bead structure and its preparation method

Abstract

This invention discloses an LED bead structure and its fabrication method. The LED bead structure includes a first prepreg substrate, a second prepreg substrate, and a third prepreg substrate stacked and fixedly connected in sequence to form a cup-shaped receiving space. The first prepreg substrate has a die-bonding portion for placing an LED chip, and the second prepreg substrate has a bonding portion adapted to the die-bonding portion. The first and second prepreg substrates have interconnected through holes, the number of which is determined by the number of bonding portions. Parts of the die-bonding portion and the bonding portion fall into different through holes. The through holes are filled with copper to form conductive portions, and the conductive portions extend leads away from the LED chip, effectively improving the airtightness of the LED bead structure and reducing the risk of copper pillar breakage.

Description

Technical Field

[0001] This invention relates to the field of LED technology, specifically to an LED lamp bead structure and its preparation method. Background Technology

[0002] Existing MIP LED devices, belonging to the small-pitch LED category, use a flat BT substrate as a support. The substrate is divided into front circuitry, back circuitry, and substrate. The front circuitry is used to bond the light-emitting chips and achieve electrical interconnection, while the back circuitry is used for soldering to the LED display module PCB. The front and back circuitry are connected and conductive. The front circuitry of the substrate is divided into a die-bonding functional area, a wire bonding functional area, and an insulating isolation area. Silver paste is used to fix the red light chip on the red die-bonding functional area, and insulating glue or silver paste is used to fix the blue and green light chips on their respective die-bonding functional areas. Finally, through molding and cutting processes, individual LED beads capable of emitting RGB three-primary-color light are obtained.

[0003] It should be noted that the substrate structure is planar, and the encapsulating adhesive does not have good airtightness with the substrate. Furthermore, due to the ink in the through-holes and the electroplated leads, moisture can more easily enter the LED chips. Additionally, insufficient heat dissipation capacity of the LED chips leads to faster aging and a shorter lifespan. Moreover, during the chip fabrication process, the thin substrate and insufficient height and strength of the through-holes make the copper pillars inside prone to breakage, causing the LED to fail. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide an LED lamp bead structure and its preparation method, which aims to improve the airtightness of the LED lamp bead structure and reduce the risk of copper column breakage.

[0005] To achieve the above objectives, the first aspect of the present invention provides the following technical solution: an LED lamp bead structure, comprising a first semi-cured substrate, a second semi-cured substrate, and a third semi-cured substrate stacked sequentially and fixedly connected to form a bowl-shaped receiving space, wherein a die-bonding portion is provided on the first semi-cured substrate for placing an LED chip, and a bonding portion adapted to the die-bonding portion is provided on the second semi-cured substrate.

[0006] The first and second prepreg substrates are provided with interconnected through holes. The number of through holes is determined by the wire bonding portion. The die bonding portion and the portion of the wire bonding portion fall into different through holes. The through holes are filled with copper to form conductive portions. The conductive portions extend out pins in a direction away from the LED chip.

[0007] Furthermore, the die-bonding portion includes a first die-bonding sub-part, a second die-bonding sub-part, and a third die-bonding sub-part that are electrically connected in sequence. The first die-bonding sub-part, the second die-bonding sub-part, and the third die-bonding sub-part are used to place different LED chips. The third die-bonding sub-part extends outward to form a first connecting part, which is used to electrically connect with the conductive part to form the negative electrode pin corresponding to the LED chip carried by the third die-bonding sub-part on the back side of the LED bead structure.

[0008] Furthermore, the bonding section includes a first bonding sub-section located on one side of the LED chip and a second bonding sub-section and a third bonding sub-section located on the other side of the LED chip. The first bonding sub-section, the second bonding sub-section, and the third bonding sub-section extend outward to form a second connecting portion, a third connecting portion, and a fourth connecting portion, respectively. The second connecting portion is electrically connected to the conductive portion to form the common electrode pin of all LED chips on the back side of the LED bead structure. The third connecting portion and the fourth connecting portion are respectively used to electrically connect to the conductive portion to form the negative electrode pin of the corresponding LED chip on the back side of the LED bead structure.

[0009] Furthermore, the die-bonding portion and the wire bonding portion are respectively pressed onto the first prepreg substrate and the second prepreg substrate to complete the fixation.

[0010] Furthermore, the first semi-cured substrate, the second semi-cured substrate, and the third semi-cured substrate form a cup-shaped receiving space for filling encapsulating adhesive.

[0011] Furthermore, the upper surface of the third prepreg substrate is higher than the top of the gold wire after the LED chip is bonded to gold wire.

[0012] Furthermore, the upper surface of the second prepreg substrate is higher than the upper surface of the LED chip.

[0013] Furthermore, the back of the LED bead structure is provided with marking points.

[0014] Furthermore, the first semi-cured substrate, the second semi-cured substrate, and the third semi-cured substrate are all made of BT resin substrate material.

[0015] To achieve the above objectives, the second aspect of the present invention provides the following technical solution: a method for preparing an LED bead structure, used to prepare the LED bead structure of the first aspect of the present invention, the method comprising:

[0016] A first prepreg substrate is provided, and the die-bonding portion is pressed onto the first prepreg substrate using PP plastic adhesive;

[0017] A second prepreg substrate is provided, and the bonding wire portion is pressed onto the second prepreg substrate using PP plastic adhesive. The second prepreg substrate with the bonding wire portion is combined with the first prepreg substrate with the die-bonding portion to obtain a combined structure.

[0018] The combined structure is formed into through holes by drilling, and the through holes are filled by copper filling process to solidify the combined structure.

[0019] A third pre-cured substrate is provided and placed on the combined structure, and fixed with PP plastic adhesive to obtain an LED lamp bead structure.

[0020] This invention provides an LED lamp bead structure and its fabrication method. The LED lamp bead structure is formed by sequentially stacking and fixing together a first semi-cured substrate, a second semi-cured substrate, and a third semi-cured substrate to form a cup-shaped receiving space. The first semi-cured substrate has a die-bonding part for placing the LED chip, and the second semi-cured substrate has a bonding part adapted to the die-bonding part. This changes the traditional planar LED lamp bead structure to a pressed cup-shaped structure, thereby improving the airtightness of the lamp bead and reducing the amount of encapsulating adhesive used, improving the performance of the lamp bead and reducing costs. In addition, the first and second semi-cured substrates have interconnected through holes. The number of through holes is determined by the bonding part. Parts of the die-bonding part and the bonding part fall into different through holes. The through holes are filled with copper to form conductive parts. The conductive parts extend out leads in a direction away from the LED chip. Due to the height difference between the lines of the first and second semi-cured substrates, the height of the copper pillar is increased, thereby improving the strength of the copper pillar and reducing the risk of copper pillar breakage. Attached Figure Description

[0021] Figure 1 This is a top view of an LED lamp bead structure with an LED chip.

[0022] Figure 2 This is a schematic diagram of an LED lamp bead structure with an LED chip.

[0023] Figure 3 This is a top view of the first prepreg substrate and the die bonding section;

[0024] Figure 4 This is a top view of the second prepreg substrate and the bonding wire section;

[0025] Figure 5 This is a top view of the third prepreg substrate and the die bonding section;

[0026] Figure 6 This is a schematic diagram of the back of the LED chip structure;

[0027] Figure 7This is a flowchart illustrating the fabrication process of an LED bead structure.

[0028] In the figure: 1. First prepreg substrate; 2. Second prepreg substrate; 3. Third prepreg substrate; 4. Through hole; 5. Lead; 61. First die bonding section; 62. Second die bonding section; 63. Third die bonding section; 64. First connector; 71. First wire bonding section; 72. Second wire bonding section; 73. Third wire bonding section; 711. Second connector; 721. Third connector; 731. Fourth connector; 8. LED chip; 9. Bonding wire; 10. Encapsulating adhesive; 11. Marker point. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Several embodiments of the invention are illustrated in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0030] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] The embodiments of the present invention will now be described.

[0033] An LED bead structure, such as Figures 1 to 6 As shown, Figure 1 This is a top view of an LED lamp bead structure with an LED chip. Figure 2 This is a schematic diagram of an LED lamp bead structure with an LED chip.

[0034] Figure 3 This is a top view of the first prepreg substrate and the die bonding section; Figure 4 This is a top view of the second prepreg substrate and the bonding wire section; Figure 5 This is a top view of the third prepreg substrate and the die bonding section; Figure 6 This is a schematic diagram of the back of an LED lamp bead structure. The LED lamp bead structure includes a first semi-cured substrate 1, a second semi-cured substrate 2, and a third semi-cured substrate 3 that are stacked and fixedly connected to form a bowl-shaped receiving space. The first semi-cured substrate 1 is provided with a die bonding part for placing the LED chip 8, and the second semi-cured substrate 2 is provided with a bonding wire part that is adapted to the die bonding part.

[0035] The first semi-cured substrate 1 and the second semi-cured substrate 2 are provided with interconnected through holes 4. The number of through holes 4 is determined according to the wire bonding part. In this embodiment, there are four through holes 4. The die bonding part and the wire bonding part fall into different through holes 4 respectively. The through holes 4 are filled with copper to form conductive parts. That is, the die bonding part and the wire bonding part are electrically connected to the corresponding conductive parts. It should be noted that other conductive materials, such as copper alloys, can also be filled. The conductive parts extend out pins 5 in the direction away from the LED chip 8. The pins 5 are fixed to the back of the LED lamp bead structure.

[0036] The die-bonding section includes a first die-bonding sub-section 61, a second die-bonding sub-section 62, and a third die-bonding sub-section 63 connected in sequence. The first die-bonding sub-section 61, the second die-bonding sub-section 62, and the third die-bonding sub-section 63 are used to place different LED chips 8. In this embodiment, the first die-bonding sub-section 61 is used to place a blue light chip, the second die-bonding sub-section 62 is used to place a green light chip, and the third die-bonding sub-section 63 is used to place a red light chip. The third die-bonding sub-section 63 extends outward to form a first connecting part 64, which is used to electrically connect with a conductive part to form a negative electrode pin corresponding to the LED chip 8 carried by the third die-bonding sub-section 63 on the back of the LED bead structure. As can be seen from the above, the third die-bonding sub-section 63 is used to place a red light chip, and the corresponding pin 5 is the R negative electrode.

[0037] Preferably, the bonding section includes a first bonding sub-section 71 located on one side of the LED chip 8, a second bonding sub-section 72 located on the other side of the LED chip 8, and a third bonding sub-section 73. The first bonding sub-section 71, the second bonding sub-section 72, and the third bonding sub-section 73 extend outward to form a second connecting portion 711, a third connecting portion 721, and a fourth connecting portion 731, respectively. The second connecting portion 711 is electrically connected to the conductive portion to form the common electrode pin of all LED chips 8 on the back side of the LED bead structure. The third connecting portion 721 and the fourth connecting portion 731 are respectively used to be electrically connected to the conductive portion to form the negative electrode pin of the corresponding LED chip 8 on the back side of the LED bead structure.

[0038] Preferably, the die-bonding portion and the wire bonding portion are pressed together with the first prepreg substrate 1 and the second prepreg substrate 2, respectively, to complete the fixation.

[0039] Preferably, the first semi-cured substrate 1, the second semi-cured substrate 2, and the third semi-cured substrate 3 form a bowl-shaped receiving space for filling the encapsulating adhesive 10.

[0040] Preferably, the upper surface of the third prepreg substrate 3 is higher than the top of the gold wire after the LED chip 8 is bonded. That is to say, the upper surface of the third prepreg substrate 3 is higher than the highest point of the arc bonding line 9.

[0041] Preferably, the upper surface of the second semi-cured substrate 2 is higher than the upper surface of the LED chip 8.

[0042] Preferably, the back of the LED bead structure is provided with a marking point 11, and the shape of the marking point 11 can be a rectangle, a triangle, etc.

[0043] Preferably, the materials of the first semi-cured substrate 1, the second semi-cured substrate 2, and the third semi-cured substrate 3 are all BT resin substrate materials.

[0044] In another embodiment of the present invention, a method for fabricating an LED bead structure is provided; please refer to [link to relevant documentation]. Figure 7 This is a flowchart illustrating the fabrication method of an LED chip structure. The method, used to fabricate the aforementioned LED chip structure, includes steps S01 to S04, specifically:

[0045] Step S01: Provide a first semi-cured substrate and press the die-bonding portion onto the first semi-cured substrate using PP plastic adhesive.

[0046] The main component of PP plastic adhesive is ethyl cyanoacrylate.

[0047] Step S02: Provide a second prepreg substrate, press the bonding wire portion onto the second prepreg substrate using PP plastic adhesive, and combine the second prepreg substrate with the bonding wire portion and the first prepreg substrate with the die bonding portion to obtain a combined structure.

[0048] In this embodiment, it is assumed that the first semi-cured substrate is a cuboid with a die-bonding portion pressed into the middle region of the cuboid surface. The second semi-cured substrate is also a cuboid and is adapted to the first semi-cured substrate. The middle region of the second semi-cured substrate is hollowed out, so that when the second semi-cured substrate is placed on the first semi-cured substrate, the die-bonding portion on the first semi-cured substrate is not blocked.

[0049] Step S03: The combined structure is drilled to form through holes, and the through holes are filled with copper to solidify the combined structure.

[0050] Specifically, the assembly structure is fixed by tooling fixtures, and through holes are formed on the first and second prepreg substrates by drilling. Copper material is then filled into the through holes to cure the assembly structure.

[0051] Step S04: Provide a third pre-cured substrate and place the third pre-cured substrate on the combined structure, and fix it with PP plastic adhesive to obtain the LED lamp bead structure.

[0052] Understandably, the third prepreg substrate is also a cuboid in shape and is adapted to the first and second prepreg substrates. Specifically, the middle area of ​​the third prepreg substrate is hollowed out. When the third prepreg substrate is placed on the second prepreg substrate, the bonding wire portion on the second prepreg substrate is exposed to facilitate the subsequent gold wire bonding process.

[0053] Because the LED chip structure is obtained through a pressing process, the airtightness of the chip can be effectively improved, while reducing the amount of encapsulating adhesive used, thereby improving chip performance and reducing manufacturing costs.

[0054] It should be noted that the third die bonding sub-part extends outward to form a first connecting part, a first bonding wire sub-part, a second bonding wire sub-part, and a third bonding wire sub-part, which in turn extend outward to form a second connecting part, a third connecting part, and a fourth connecting part, all of which are located in the through hole. When the through hole is filled by the copper filling process, the copper pillar formed in the through hole is electrically connected to the first connecting part, the second connecting part, the third connecting part, and the fourth connecting part.

[0055] In the actual production of LED chips, LED chips that emit different colors of light are first die-bonded onto the corresponding first die-bonding section, second die-bonding section, and third die-bonding section. Then, the positive and negative electrodes of the LED chips are electrically connected to the corresponding bonding wire sections through a gold wire bonding process. Since the bonding wire area is higher than the die-bonding area, the amount of bonding wire used can be reduced, thereby reducing costs. Finally, the chips are encapsulated through a dispensing process and cut to form high-airtightness LED chips.

[0056] In summary, the present invention proposes an LED lamp bead structure and its manufacturing method. This LED lamp bead structure is formed by sequentially stacking and fixing together a first prepreg substrate, a second prepreg substrate, and a third prepreg substrate to create a cup-shaped receiving space. The first prepreg substrate has a die-bonding portion for placing the LED chip, and the second prepreg substrate has a bonding portion adapted to the die-bonding portion. This transforms the traditional planar LED lamp bead structure into a pressed cup-shaped structure, thereby improving the lamp bead's airtightness and reducing the amount of encapsulating adhesive used, improving lamp bead performance, and reducing costs. Furthermore, the first and second prepreg substrates have interconnected through-holes, the number of which is determined by the bonding portion. The die-bonding portion and the bonding portion fall into different through-holes, which are filled with copper to form conductive portions. The conductive portions extend leads away from the LED chip. Due to the height difference between the lines on the first and second prepreg substrates, the copper pillar height is increased, thereby improving the copper pillar strength and reducing the risk of copper pillar breakage.

[0057] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0058] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An LED lamp bead structure, characterized in that, It includes a first semi-cured substrate, a second semi-cured substrate, and a third semi-cured substrate that are stacked sequentially and fixedly connected to form a bowl-shaped receiving space. The first semi-cured substrate is provided with a die-bonding part for placing LED chips, and the second semi-cured substrate is provided with a bonding wire part adapted to the die-bonding part. The first semi-cured substrate and the second semi-cured substrate are provided with interconnecting through holes. The number of through holes is determined according to the bonding wire portion. The die bonding portion and the portion of the bonding wire portion fall into different through holes. The through holes are filled with copper to form conductive portions. The conductive portions extend out pins in a direction away from the LED chip. The die-bonding section includes a first die-bonding sub-section, a second die-bonding sub-section, and a third die-bonding sub-section that are electrically connected in sequence. The first die-bonding sub-section, the second die-bonding sub-section, and the third die-bonding sub-section are used to place different LED chips. The third die-bonding sub-section extends outward to form a first connecting portion. The first connecting portion is used to electrically connect with the conductive portion to form the negative electrode pin corresponding to the LED chip carried by the third die-bonding sub-section on the back side of the LED bead structure. The bonding section includes a first bonding sub-section located on one side of the LED chip, a second bonding sub-section located on the other side of the LED chip, and a third bonding sub-section. The first bonding sub-section, the second bonding sub-section, and the third bonding sub-section extend outward to form a second connecting portion, a third connecting portion, and a fourth connecting portion, respectively. The second connecting portion is electrically connected to the conductive portion to form the common electrode pin of all LED chips on the back side of the LED bead structure. The third connecting portion and the fourth connecting portion are respectively used to electrically connect to the conductive portion to form the negative electrode pin of the corresponding LED chip on the back side of the LED bead structure.

2. The LED lamp bead structure according to claim 1, characterized in that, The die-bonding portion and the bonding wire portion are respectively pressed onto the first prepreg substrate and the second prepreg substrate to complete the fixation.

3. The LED lamp bead structure according to claim 2, characterized in that, The first semi-cured substrate, the second semi-cured substrate, and the third semi-cured substrate form a bowl-shaped receiving space for filling encapsulating adhesive.

4. The LED lamp bead structure according to claim 3, characterized in that, The upper surface of the third semi-cured substrate is higher than the top of the gold wire after the LED chip is bonded to gold wire.

5. The LED lamp bead structure according to claim 4, characterized in that, The upper surface of the second semi-cured substrate is higher than the upper surface of the LED chip.

6. The LED lamp bead structure according to claim 1, characterized in that, The back of the LED bead structure has marking points.

7. The LED lamp bead structure according to claim 1, characterized in that, The first semi-cured substrate, the second semi-cured substrate, and the third semi-cured substrate are all made of BT resin substrate material.

8. A method for fabricating an LED bead structure, characterized in that, The method for preparing the LED lamp bead structure according to any one of claims 1 to 7 comprises: A first prepreg substrate is provided, and the die-bonding portion is pressed onto the first prepreg substrate using PP plastic adhesive; A second prepreg substrate is provided, and the bonding wire portion is pressed onto the second prepreg substrate using PP plastic adhesive. The second prepreg substrate with the bonding wire portion is combined with the first prepreg substrate with the die-bonding portion to obtain a combined structure. The combined structure is formed into through holes by drilling, and the through holes are filled by copper filling process to solidify the combined structure. A third pre-cured substrate is provided and placed on the combined structure, and fixed with PP plastic adhesive to obtain an LED lamp bead structure.

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