Packaging structure and packaging method of three-color LED chip

Abstract

The application discloses a packaging structure of a three-color LED chip and a packaging method thereof, and the packaging structure comprises an LED support, a driving integrated circuit and a three-color LED chip. When a red light LED chip (12) of the three-color LED chip is a reverse chip, a forward fixed conductive terminal (3) of the LED support is used as a conversion pin, and a reverse fixed conductive terminal (4) of the LED support is used to regard an electrode of the red light LED chip (12) as a welding spot, so that welding lines can be welded only once.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor light source LED packaging, and in particular to a packaging structure and packaging method for a three-color LED chip. Background Art

[0002] Almost all colors found in nature can be created by mixing red, green, and blue monochromatic lights in varying proportions. These three colors are called primary colors. RGB-LEDs are single LEDs that combine red, green, and blue chips in a single package. By varying the driving current of the three chips, different luminous fluxes of different colors can be achieved. By mixing different amounts of the three colors, different colors can be created.

[0003] Figure 1 This is a schematic diagram of LED chip packaging in which the red light chip is a reverse chip in conventional technology. Conventional three-color LED lamp beads include RGB three-color LED chips (blue light chip 10, green light chip 11 and red light chip 12), a colorful driver integrated circuit (driver IC) 13 and an LED mounting bracket. The LED mounting bracket is a bracket containing eight conductive terminals (1# to 8# conductive terminals). The three-color LED chips and driver ICs are respectively fixed on the chip fixing positions of the corresponding conductive terminals, that is, the driver IC 13 is placed on the chip fixing position of the 7# conductive terminal, the blue light chip 10 is placed on the chip fixing position of the 1# conductive terminal, and the green light chip 11 is placed on the chip fixing position of the 2# conductive terminal. Due to the special material and structure of the red light chip 12, there is only one electrode on its surface and another electrode on the bottom. According to the polarity of the surface electrode, it is divided into forward red light chip (the surface is positive pole P) and reverse red light chip (the surface is negative pole N). Different chips use different installation and welding methods. At present, the reverse red light chip packaging method is generally adopted. When the red light chip 12 is a reverse chip, the red light chip 12 is placed on the chip fixing position of the 4# conductive terminal.

[0004] In the packaging process of the prior art, when welding the bonding gold wire, the first welding place is defined as the first welding point of the bonding wire, and the second welding place is defined as the second welding point of the bonding wire. During welding, in order to increase the adhesion between the bonding gold wire and the welding point to improve the firmness of the welding, it is usually necessary to increase the welding area. Usually, during the first welding, technical means can be used to make the end of the bonding gold wire spherical, so that the first welding point of the bonding wire is actually a sphere in contact with the welded part, and the adhesion is sufficient; however, during the second welding, process limitations prevent the formation of a sphere on the bonding gold wire. Therefore, it is necessary to generate an alloy ball at the welded part in advance, and then press the bonding gold wire onto this generated alloy ball to form the second welding point of the bonding wire with sufficient adhesion.

[0005] In the prior art, when welding an inverted red LED chip, a conventional welding method is to select the red signal output port on the driver integrated circuit 13 as the first welding point. After the first welding point is welded, the bonding gold wire is pulled from the red signal output port on the driver integrated circuit 13 to directly connect the red signal output port on the driver integrated circuit 13 to the negative electrode N of the inverted red chip with the bonding gold wire. At this time, the negative electrode N of the inverted red LED chip is regarded as the second welding point, that is, it is necessary to first generate an alloy ball on the negative electrode N (first welding), and then weld the bonding gold wire to the alloy ball (second welding). Obviously, the negative electrode N of the inverted red LED chip will be welded twice. Because the red LED chip body is relatively brittle, welding twice will cause a certain proportion of the negative electrode N of the red LED chip to fall off or the electrode to be damaged. The electrode falling off will be reflected in the test process as a loss of product function. The electrode is damaged but not completely falling off, which may be reflected in the test process as a loss of product function, or it may be reflected in the test process that its function is normal, but it will be reflected in the finished product as a loss of function or functional instability. Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a packaging structure and packaging method for a three-color LED chip, so as to avoid the red light chip electrode being soldered twice, avoid the red light chip electrode falling off or the electrode being damaged, thereby improving the product yield and product life.

[0007] To achieve the above and other objectives, the present invention proposes a packaging structure for a three-color LED chip, including an LED bracket, a driver integrated circuit, and a three-color LED chip. The structure is characterized in that when the red LED chip of the three-color LED chip is a reverse chip, the forward fixed conductive terminal of the LED bracket is used as a conversion pin, and the reverse fixed conductive terminal of the LED bracket is used to treat the red LED chip electrode as a solder joint, so that the wire bonding can be completed in a single step.

[0008] Preferably, when the red LED chip of the three-color LED chip is a reverse chip, the red LED chip is fixed to the chip fixing position of the reverse fixed conductive terminal of the LED bracket, the red signal output port of the driver integrated circuit is connected to the forward fixed conductive terminal of the LED bracket, and the N electrode of the reverse red LED chip is connected to the forward fixed conductive terminal of the LED bracket.

[0009] Preferably, when the red LED chip of the three-color LED chip is a forward chip, the red LED chip is placed on the chip fixing position of the forward fixed conductive terminal of the LED bracket, the red signal output port of the driver integrated circuit is connected to the forward fixed conductive terminal, and the P electrode of the forward red LED chip is connected to the reverse fixed conductive terminal.

[0010] To achieve the above object, the present invention further provides a method for packaging a three-color LED chip, comprising the following steps:

[0011] Step S1, performing a die bonding process to fix the blue LED chip, green LED chip, red LED chip, and driver integrated circuit to the chip fixing positions of the corresponding conductive terminals in the LED bracket;

[0012] Step S2 is a wire bonding process in which the conductive terminals of the LED bracket are connected to the electrodes of the blue LED chip, the green LED chip, the red LED chip, and the port of the driver integrated circuit to establish an electrical or signal communication connection. When the red LED chip is a reverse-direction chip, the forward-direction conductive terminal is used as a conversion pin, and the reverse-direction conductive terminal is used to treat the red LED chip electrode as a solder joint, so that the wire bonding can be completed in one step.

[0013] Preferably, step S1 includes:

[0014] S11, fixing the driver integrated circuit, placing the driver integrated circuit on the chip fixing position of the seventh conductive terminal of the LED bracket;

[0015] S12, fixing the blue LED chip, placing the blue LED chip on the chip fixing position of the first conductive terminal of the LED bracket, and fixing it with non-conductive glue;

[0016] S13, fixing the green LED chip, placing the green LED chip on the chip fixing position of the second conductive terminal of the LED bracket, and fixing it with non-conductive glue;

[0017] S14, when the red LED chip is a reverse chip, placing the red LED chip on the chip fixing position of the reverse fixed conductive terminal of the LED bracket.

[0018] Preferably, in step S14, when the red LED chip is a forward chip, the red LED chip is placed on a chip fixing position of a forward fixed conductive terminal of the LED bracket.

[0019] Preferably, in step S2, when the red LED chip is a reverse chip, the red signal output port of the driver integrated circuit is connected to the forward fixed conductive terminal, and the N electrode of the reverse red LED chip is connected to the forward fixed conductive terminal.

[0020] Preferably, in step S2, when the red LED chip is a forward chip, the red signal output port of the driver integrated circuit is connected to the forward conductive terminal, and the P electrode of the forward red LED chip is connected to the reverse fixed conductive terminal.

[0021] Preferably, step S2 includes:

[0022] S21, connecting the GND port of the driver integrated circuit to the eighth conductive terminal of the LED bracket;

[0023] S22, connecting the DOUT port of the driver integrated circuit to the seventh conductive terminal 7 of the LED bracket;

[0024] S23, connecting the DIN port of the driver integrated circuit to the sixth conductive terminal of the LED bracket;

[0025] S24, connecting the VDD port of the driver integrated circuit to the fifth conductive terminal of the LED bracket;

[0026] S25, soldering the blue LED chip, connecting the blue signal output port of the driver integrated circuit to the cathode of the blue LED chip, and connecting the anode of the blue LED chip to the first conductive terminal of the LED bracket;

[0027] S26, soldering the green LED chip, connecting the green signal output port of the driver integrated circuit to the cathode of the green LED chip, and connecting the anode of the green LED chip to the second conductive terminal of the LED bracket;

[0028] S27, soldering the red LED chip. When the red LED chip is a forward chip, connect the red signal output port of the driver integrated circuit to the forward fixed conductive terminal of the LED bracket, and connect the positive electrode P of the forward red LED chip to the reverse fixed conductive terminal. When the red LED chip is a reverse chip, connect the red signal output port of the driver integrated circuit to the forward fixed conductive terminal, and connect the N electrode of the reverse red LED chip to the forward fixed conductive terminal.

[0029] Preferably, in step S27, when the red light LED chip is a reverse chip, the red signal output port of the driver integrated circuit is used as a bonding wire-welding point to connect the red signal output port of the driver integrated circuit to the forward fixed conductive terminal with a bonding gold wire, and the negative electrode N of the reverse red light LED chip is used as a bonding wire-welding point to connect the negative electrode N of the reverse red light LED chip to the forward fixed conductive terminal with a bonding gold wire.

[0030] Compared with the prior art, the packaging structure and packaging method of a three-color LED of the present invention connects the red signal output port of the magic color driver IC to the forward fixed conductive terminal of the LED when the red light LED chip is a reverse chip, and connects the N electrode of the reverse red light LED chip to the forward fixed conductive terminal, thereby avoiding the red chip electrode from being welded twice, preventing the red light chip electrode from falling off or being damaged, and improving the product yield and product life. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of LED chip packaging in which the red light chip is an inverted chip in conventional technology;

[0032] Figure 2 This is a system structure diagram of a packaging structure of a three-color LED chip in which the red light chip is a reverse chip in one embodiment of the present invention;

[0033] Figure 3 This is a system structure diagram of a packaging structure of a three-color LED chip in which the red light chip is a forward chip in another embodiment of the present invention;

[0034] Figure 4 This is a flow chart of the steps of a packaging method for a three-color LED chip of the present invention. DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present invention using specific examples and accompanying drawings. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through other different specific examples, and the details in this specification may be modified and altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0036] Figure 2 This is a system structure diagram of a packaging structure of a three-color LED chip in which the red light chip is a reverse chip in one embodiment of the present invention. Figure 3 This is a system structure diagram of a three-color LED chip packaging structure in which the red light chip is a forward chip in another embodiment of the present invention. The present invention provides a three-color LED chip packaging structure, including an LED bracket, a magic color driver integrated circuit, and a three-color LED chip.

[0037] The LED bracket includes eight conductive terminals, and the three-color LED chips include a blue LED chip 10, a green LED chip 11, and a red LED chip 12. The magic color driving integrated circuit 13 is placed on the chip fixing position of the seventh conductive terminal 7 of the LED bracket and fixed with non-conductive glue. The blue LED chip 10 is placed on the chip fixing position of the first conductive terminal 1 of the LED bracket and fixed with non-conductive glue, that is, the positive electrode of the blue LED chip 10 is connected to the first conductive terminal 1, and its negative electrode is connected to the blue signal output port of the magic color driving integrated circuit 13; the green LED chip 11 is placed on the chip fixing position of the second conductive terminal 2 of the LED bracket and fixed with non-conductive glue, that is, the positive electrode of the green LED chip 11 is connected to the second conductive terminal 2, and its negative electrode is connected to the green signal output port of the magic color driving integrated circuit 13; due to the special material and structure of the red LED chip 12, there is only one electrode on its surface and another electrode on the bottom. According to the polarity of the surface electrode, the red LED chip 12 is divided into a forward red light LED chip (the surface is the positive electrode P) and a reverse red light LED chip (the surface is the negative electrode N). When the red light LED chip 12 is a forward chip, the red light LED chip 12 is placed on the chip fixing position of the third conductive terminal 3 of the LED bracket and fixed with conductive silver glue. The red signal output port of the magic color driving integrated circuit 13 is connected to the third conductive terminal 3 (also referred to as the forward fixed conductive terminal in the present invention), and the P electrode of the forward red light LED chip 12 is connected to the fourth conductive terminal 4; when the red light LED chip 12 is a reverse chip, the red light LED chip 12 is placed on the chip fixing position of the fourth conductive terminal 4 of the LED bracket (also referred to as the reverse fixed conductive terminal in the present invention) and fixed with conductive silver glue. The red signal output port of the magic color driving integrated circuit 13 is connected to the third conductive terminal 3, and the N electrode of the reverse red light LED chip is connected to the third conductive terminal 3.

[0038] In an embodiment of the present invention, the GND port of the magic color driver integrated circuit 13 is connected to the eighth conductive terminal 8 of the LED bracket; the DOUT port of the magic color driver integrated circuit 13 is connected to the seventh conductive terminal 7 of the LED bracket; the DIN port of the magic color driver integrated circuit 13 is connected to the sixth conductive terminal 6 of the LED bracket; and the VDD port of the magic color driver integrated circuit 13 is connected to the fifth conductive terminal 5 of the LED bracket.

[0039] It should be noted that, in the embodiment of the present invention, 9 is a notched edge of the LED bracket including eight conductive terminals, which is used for viewing directions and will not be described in detail here.

[0040] Figure 4 This is a flow chart of the steps of a packaging method for a three-color LED chip of the present invention. Figure 4 As shown, the present invention provides a packaging method for a three-color LED chip, comprising the following steps:

[0041] In step S1 , a die-bonding process is performed to fix the blue LED chip 10 , the green LED chip 11 , the red LED chip 12 and the color-matching driver integrated circuit 13 to the chip fixing positions of the corresponding conductive terminals in the LED bracket.

[0042] Specifically, step S1 further includes:

[0043] S11, fixing the magic color driving integrated circuit 13, placing the magic color driving integrated circuit 13 on the chip fixing position of the seventh conductive terminal 7 of the LED bracket, and fixing it with non-conductive glue;

[0044] S12, fixing the blue LED chip 10, placing the blue LED chip 10 on the chip fixing position of the first conductive terminal 1 of the LED bracket, and fixing it with non-conductive glue;

[0045] S13, fixing the green LED chip 11, placing the green LED chip 11 on the chip fixing position of the second conductive terminal 2 of the LED bracket, and fixing it with non-conductive glue;

[0046] S14, fix the red LED chip 12. Due to the special material and structure of the red LED chip 12, it has only one electrode on its surface and another electrode on its bottom. According to the polarity of the surface electrode, it is divided into forward red LED chips (the surface is the positive electrode P) and reverse red LED chips (the surface is the negative electrode N). Different chips use different installation and welding methods:

[0047] S14a, when the red LED chip 12 is a forward-facing chip, place the red LED chip 12 on the chip fixing position of the third conductive terminal 3 (forward-facing fixed conductive terminal) of the LED bracket and fix it with conductive silver glue;

[0048] S14b, when the red LED chip 12 is a reverse chip, the red LED chip 12 is placed on the chip fixing position of the fourth conductive terminal 4 (reverse fixed conductive terminal) of the LED bracket and fixed with conductive silver glue.

[0049] Step S2 is a wire bonding process in which the conductive terminals of the LED bracket are connected to the electrodes of the blue LED chip 10, the green LED chip 11, and the red LED chip 12 and the ports of the color-shifting driver integrated circuit 13 to establish electrical or signal communication connections. When the red LED chip is a reverse-direction chip, the forward-direction conductive terminal serves as a conversion pin, and the reverse-direction conductive terminal acts as a solder joint to treat the electrodes of the red LED chip 12 as a solder joint, so that the wire bonding can be completed in a single pass.

[0050] Specifically, when the red LED chip 12 is a forward chip, the red signal output port of the magic color driving integrated circuit 13 is connected to the third conductive terminal 3 (forward fixed conductive terminal), and the P electrode of the forward red chip is connected to the fourth conductive terminal 4 (reverse fixed conductive terminal); when the red LED chip 12 is a reverse chip, the red signal output port of the magic color driving integrated circuit 13 is connected to the third conductive terminal 3 (forward fixed conductive terminal), and the N electrode of the reverse red LED chip 12 is connected to the third conductive terminal 3 (forward fixed conductive terminal).

[0051] Furthermore, step S2 includes:

[0052] S21, connecting the GND port of the magic color driving integrated circuit 13 to the eighth conductive terminal 8 of the LED bracket using a bonding wire;

[0053] S22, connecting the DOUT port of the magic color driving integrated circuit 13 to the seventh conductive terminal 7 of the LED bracket using a bonding wire;

[0054] S23, connecting the DIN port of the magic color driving integrated circuit 13 to the sixth conductive terminal 6 of the LED bracket using a bonding wire;

[0055] S24, connecting the VDD port of the magic color driving integrated circuit 13 to the fifth conductive terminal 5 of the LED bracket using a bonding wire;

[0056] S25, soldering the blue LED chip 10, connecting the blue signal output port of the magic color driving integrated circuit 13 to the cathode of the blue LED chip 10 with a bonding gold wire, and connecting the anode of the blue LED chip 10 to the first conductive terminal 1 of the LED bracket with a bonding gold wire;

[0057] S26, soldering the green LED chip 11, connecting the green signal output port of the magic color driver integrated circuit 13 to the cathode of the green LED chip 11 with a bonding gold wire, and connecting the anode of the green LED chip 11 to the second conductive terminal 2 of the LED bracket with a bonding gold wire;

[0058] S27, soldering the red LED chip 12. Due to the special material and structure of the red LED chip 12, it has only one electrode on its surface and another electrode on its bottom. According to the polarity of the surface electrode, it is divided into forward red LED chips (with positive electrode P on the surface) and reverse red LED chips (with negative electrode N on the surface). Different chips use different installation and soldering methods:

[0059] S27a, when the red LED chip 12 is a forward chip, the red signal output port of the color drive integrated circuit 13 is connected with the third conductive terminal 3 (a forward fixed conductive terminal) of the LED support by bonding gold wire, and the positive pole P of the forward red LED chip 12 (the surface is positive P) is connected with the fourth conductive terminal 4 (a reverse fixed conductive terminal) by bonding gold wire;

[0060] S27b, when the red LED chip 12 is a reverse chip (the surface is negative N), the red signal output port of the color drive integrated circuit 13 is connected with the third conductive terminal 3 by bonding gold wire, and the N electrode of the reverse red LED chip 12 is connected with the third conductive terminal 3 by bonding gold wire, that is, when the red LED chip is a reverse chip (the surface is negative N), the red signal output port of the color drive integrated circuit 13 is connected with the third conductive terminal 3 by bonding gold wire with the red signal output port of the color drive integrated circuit 13 as a soldering wire-soldering point, and the N electrode of the reverse red LED chip is connected with the third conductive terminal 3 by bonding gold wire with the negative electrode N of the reverse red LED chip as a soldering wire-soldering point.

[0061] It can be seen that the packaging structure and packaging method of the three-color LED of the present application can connect the red signal output port of the color drive IC with the forward fixed conductive terminal of the LED and connect the N electrode of the reverse red LED chip with the forward fixed conductive terminal when the red LED chip is a reverse chip, thereby avoiding welding the red chip electrode twice, avoiding the phenomenon of electrode falling off or electrode damage of the red light chip, improving the product yield and product life, and the method of the present application can also use a forward red chip, so that the color RGB lamp bead can match the common 5050 RGB lamp bead with a notch as a positive pole on the market, so as to reduce the cost.

[0062] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify and change the above embodiments without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be as listed in the claims.

Claims

1. A packaging method for a three-color LED chip, characterized in that: The steps include: Step S1, performing a die-bonding process to respectively fix the blue LED chip (10), the green LED chip (11), the red LED chip (12), and the driver integrated circuit (13) to the chip fixing positions of the corresponding conductive terminals in the LED bracket; Step S2, performing a wire bonding process to connect the conductive terminals of the LED bracket to the electrodes of the blue LED chip (10), the green LED chip (11), the red LED chip (12) and the ports of the driver integrated circuit (13) by welding, thereby establishing electrical or signal communication connections; Wherein, when the red light LED chip is a reverse chip, the red light LED chip (12) is placed on the chip fixing position of the reverse fixed conductive terminal of the LED bracket, the forward fixed conductive terminal is used as a conversion pin, and the reverse fixed conductive terminal is coordinated to set the red light LED chip (12) electrode and the port of the driver integrated circuit (13) as a welding wire-welding point, so that the red light LED chip (12) electrode only needs to be welded once; the red light LED chip (12) is a reverse chip, which means that the electrode on the surface of the red light LED chip (12) is a negative electrode N, and the electrode on the bottom surface is a positive electrode P; When the red light LED chip (12) is a forward chip, the electrodes of the red light LED chip (12) and the ports of the driver integrated circuit (13) are both set as welding wires and welding points, and the red light LED chip (12) is placed on the chip fixing position of the forward fixed conductive terminal of the LED bracket; the red light LED chip (12) is a forward chip, which means that the electrode on the surface of the red light LED chip (12) is a positive electrode P, and the electrode on the bottom surface is a negative electrode N.

2. A packaging method for a three-color LED chip according to claim 1, characterized in that: Step S1 includes: S11, fixing the driver integrated circuit (13), placing the driver integrated circuit (13) on the chip fixing position of the seventh conductive terminal (7) of the LED bracket; S12, fixing the blue LED chip (10), placing the blue LED chip (10) on the chip fixing position of the first conductive terminal (1) of the LED bracket, and fixing it with non-conductive glue; S13, fixing the green LED chip (11), placing the green LED chip (11) on the chip fixing position of the second conductive terminal (2) of the LED bracket, and fixing it with non-conductive glue.

3. The packaging method of a three-color LED chip according to claim 1, wherein: In step S2, when the red LED chip (12) is a reverse chip, the red signal output port of the driver integrated circuit (13) is connected to the forward fixed conductive terminal, and the negative electrode N of the reverse red LED chip (12) is connected to the forward fixed conductive terminal.

4. The packaging method of a three-color LED chip according to claim 3, wherein: In step S2, when the red LED chip (12) is a forward chip, the red signal output port of the driver integrated circuit (13) is connected to the forward fixed conductive terminal, and the positive electrode P of the forward red LED chip (12) is connected to the reverse fixed conductive terminal.

5. The packaging method of a three-color LED chip according to claim 1, wherein: Step S2 includes: S21, connecting the GND port of the driver integrated circuit (13) to the eighth conductive terminal of the LED bracket; S22, connecting the DOUT port of the driver integrated circuit (13) to the seventh conductive terminal (7) of the LED bracket; S23, connecting the DIN port of the driver integrated circuit (13) to the sixth conductive terminal of the LED bracket; S24, connecting the VDD port of the driver integrated circuit (13) to the fifth conductive terminal of the LED bracket; S25, welding the blue LED chip (10), connecting the blue signal output port of the driver integrated circuit (13) to the cathode of the blue LED chip (10), and connecting the anode of the blue LED chip (10) to the first conductive terminal of the LED bracket; S26, welding the green LED chip (11), connecting the green signal output port of the driver integrated circuit (13) to the negative electrode of the green LED chip (11), and connecting the positive electrode of the green LED chip (11) to the second conductive terminal of the LED bracket; S27, welding the red LED chip (12). When the red LED chip (12) is a forward chip, the red signal output port of the driver integrated circuit (13) is connected to the forward fixed conductive terminal of the LED bracket, and the positive electrode P of the forward red LED chip (12) is connected to the reverse fixed conductive terminal. When the red LED chip 12 is a reverse chip, the red signal output port of the driver integrated circuit (13) is connected to the forward fixed conductive terminal, and the negative electrode N of the reverse red LED chip (12) is connected to the forward fixed conductive terminal.

6. The packaging method of a three-color LED chip according to claim 5, wherein: In step S27, when the red LED chip (12) is a reverse chip, the red signal output port of the driver integrated circuit (13) is used as a bonding wire and a welding point to connect the red signal output port of the driver integrated circuit (13) to the positive fixed conductive terminal with a bonding gold wire, and the negative electrode N of the reverse red LED chip (12) is used as a bonding wire and a welding point to connect the negative electrode N of the reverse red LED chip (12) to the positive fixed conductive terminal with a bonding gold wire.

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