A module and a manufacturing method thereof

Abstract

The present invention provides a module and a manufacturing method thereof, comprising an aluminum substrate, a heat sink, a power device chip, a rectifier diode, a metal bead, pins, and a plastic encapsulation material. The heat sink is welded to the aluminum substrate. The bottom surface of the power device chip serves as a source electrode, and the top surface of the power device chip serves as a drain electrode. The source electrode is electrically connected to the heat sink, and the drain electrode is electrically connected to the metal bead. The back surface of the rectifier diode serves as a cathode, and the front surface of the rectifier diode serves as a positive electrode. The cathode of the rectifier diode is electrically connected to the source electrode of the power device chip via the heat sink, and the positive electrode is electrically connected to the drain electrode of the power device chip via the metal bead. The metal bead is electrically connected to the power device chip, the rectifier diode, and the aluminum substrate, respectively. The pins are used to connect to the circuit on an external electronic control board to achieve electrical connection, connect the power device chip to a power source, and transmit signals to the outside world. The heat sink, power device chip, rectifier diode, and metal bead are disposed within the plastic encapsulation material. The present invention can save equipment costs and improve production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of modular intelligent power systems, and in particular to a module and a manufacturing method thereof. Background Art

[0002] As society continues to progress, the demand for electrical equipment is also evolving. A power device, or MIPS (Module Intelligent Power System), is a power driver product that combines power electronics and integrated circuit technologies. MIPS not only integrates power switching devices and driver circuitry, but also features built-in fault detection circuitry for overvoltage, overcurrent, and overtemperature, sending detection signals to the CPU or DSP for interrupt processing. It consists of a high-speed, low-power die, optimized gate-level driver circuitry, and fast protection circuitry. This protects the MIPS from damage even in the event of load failures or improper use. MIPS typically uses IGBTs as power switching elements and integrates current sensors and driver circuitry. Traditional intelligent power modules typically use high-voltage driver ICs to drive the IGBTs, typically employing a six-way three-phase full-bridge driver. They are widely used in industrial control, household appliances, and other fields.

[0003] Since the current passing through the existing power device chips and rectifier diode chips is very large during operation, see the attached Figure 5 As shown, a thick aluminum wire with a diameter of 20 mils is welded between the power device and the rectifier diode, as well as between them and the aluminum substrate 101, to achieve electrical connection and ensure that the aluminum wire does not melt when the power module is operating. The working principle of current aluminum wire welding equipment is that the welding needle 104 outputs pressure to directly press the end point of the aluminum wire 103 onto the chip 102 solder joint, so that the aluminum wire and the metal of the solder joint on the chip surface form an alloy. To avoid poor conductivity at the solder joint, the larger the diameter of the welding aluminum wire, the greater the pressure required from the welding needle. However, the semiconductor material of the chip is hard and brittle, and excessive pressure from the welding needle will crush the chip solder joint to form a crater. This damages the surface of the chip, resulting in poor product quality and low production efficiency. At the same time, the use of welding aluminum wire requires corresponding route bonding machine processing, which increases the cost of the equipment. Summary of the Invention

[0004] In view of the deficiencies of the above related technologies, the present invention proposes a module and a manufacturing method thereof which are low in cost, good in product quality and convenient for improving production efficiency.

[0005] In order to solve the above technical problems, in the first aspect, an embodiment of the present invention provides a module, including: an aluminum substrate, a heat sink, a power device chip, a rectifier diode, a metal bead, a pin and a plastic packaging material, the heat sink is welded on the aluminum substrate, the bottom surface of the power device chip is the source, the top surface of the power device chip is the drain, the source is electrically connected to the heat sink, and the drain is electrically connected to the metal bead; the back of the rectifier diode is the negative electrode, the front of the rectifier diode is the positive electrode, the negative electrode of the rectifier diode is electrically connected to the source of the power device chip via the heat sink, and the positive electrode of the rectifier diode is electrically connected to the drain of the power device chip via the metal bead; the metal bead is electrically connected to the power device chip, the rectifier diode and the aluminum substrate respectively; the pin is used to connect to the circuit on the external electronic control board to connect the power device chip to the power supply and transmit signals to the outside world; the heat sink, the power device chip, the rectifier diode and the metal bead are arranged in the plastic packaging material.

[0006] Preferably, the metal molding includes a molding body, a first contact portion, a second contact portion and a third contact portion formed by the molding body protruding toward the direction of the aluminum substrate, the first contact portion is electrically connected to the drain of the power device chip, the second contact portion is electrically connected to the positive pole of the rectifier diode, and the third contact portion is electrically connected to the aluminum substrate.

[0007] Preferably, the first contact portion is soldered to the drain of the power device chip via solder paste, the second contact portion is soldered to the anode of the rectifier diode via solder paste, and the third contact portion is soldered to the aluminum substrate via solder paste.

[0008] Preferably, the first contact portion, the second contact portion and the third contact portion are respectively provided with a first through hole, a second through hole and a third through hole formed therethrough.

[0009] Preferably, the first through hole and the third through hole are both square structures, and the second through hole is a circular structure.

[0010] Preferably, the first contact portion and the second contact portion have the same height relative to the pressure strip body, and the third contact portion has a height relative to the pressure strip body greater than the first contact portion and the second contact portion have a height relative to the pressure strip body.

[0011] Preferably, the module further comprises a plurality of resistors arranged on the aluminum substrate, and the plurality of resistors are electrically connected to the aluminum substrate.

[0012] Preferably, the module further comprises a plurality of thin aluminum wires, and the plurality of thin aluminum wires are respectively connected to the aluminum substrate and the gate of the power device chip.

[0013] Preferably, one side of the aluminum substrate is provided with a circuit wiring, and the circuit wiring is provided with solder joints for mounting the heat sink, the pins, the plurality of thin aluminum wires, the driver IC chip and the capacitance and resistance components.

[0014] In a second aspect, an embodiment of the present invention further provides a method for manufacturing a module, the method comprising the following steps:

[0015] S1. Soft material welding: Heat the copper heat sink to about 350°C in a nitrogen-protected environment, apply a layer of solder with a melting point of 330°C on the surface of the heat sink, and mount the power device chip and rectifier diode chip on the heat sink;

[0016] S2, solder paste printing: brush solder paste with a melting point of 220℃ on the aluminum substrate where the components are to be mounted;

[0017] S3, first SMT patch: mount the heat sink assembly with power devices, capacitors, and resistors onto the heat sink;

[0018] S4, chip installation: mount the driver IC onto the aluminum substrate;

[0019] S5, tinning: spray tin paste on the drain surface of the power device and the positive surface of the rectifier diode;

[0020] S6. Second SMT patch: install metal strips;

[0021] S7. Install the pins: mount the pins to the corresponding solder joints on the aluminum substrate;

[0022] S8, reflow soldering: The product passes through a reflow oven with a peak temperature set at 230°C to solidify the power device chip onto the aluminum substrate, and solidify the metal bead onto the product;

[0023] S9. Thin aluminum wire welding: Weld aluminum wires with a diameter of 1.5 mil between the solder joints of the driver IC chip and the aluminum substrate, and between the gate solder joints of the power device chip and the aluminum substrate to achieve electrical connection between them;

[0024] S10, injection molding and fixing: encapsulating the product into the interior of the plastic packaging material by injection molding;

[0025] S11, laser marking: marking product information on the outer shell of the product plastic packaging material;

[0026] S12, manufacturing and forming: punching and bending the pins into the required shape.

[0027] Compared with the related art, the present invention welds the heat sink onto the aluminum substrate, the bottom surface of the power device chip is the source electrode, the top surface of the power device chip is the drain electrode, the source electrode is electrically connected to the heat sink, and the drain electrode is electrically connected to the metal bead; the back surface of the rectifier diode is the negative electrode, the front surface of the rectifier diode is the positive electrode, the negative electrode of the rectifier diode is electrically connected to the source electrode of the power device chip via the heat sink, and the positive electrode of the rectifier diode is electrically connected to the drain electrode of the power device chip via the metal bead; the metal bead is electrically connected to the power device chip, the rectifier diode and the aluminum substrate respectively; the pin is used to connect to the circuit on the external electronic control board to connect the power device chip to the power supply and transmit signals to the outside world; the heat sink, the power device chip, the rectifier diode and the metal bead are arranged in the plastic packaging material; the metal bead is cured to the surface of the power chip by the solder paste reflow process without damaging the chip surface, which can improve the product yield; the production line does not require a thick aluminum wire bonding machine, saving equipment costs, and thus can improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described in detail below with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made with reference to the following drawings. In the accompanying drawings:

[0029] Figure 1 Schematic diagram of the structure of the module of the present invention;

[0030] Figure 2 Schematic diagram of the three-dimensional structure of the module of the present invention;

[0031] Figure 3 This is a schematic structural diagram of the metal layer of the module of the present invention;

[0032] Figure 4 is a flow chart of a method for manufacturing a module of the present invention;

[0033] Figure 5 Schematic diagram of the structure of a power module in the prior art.

[0034] In the figure, 201, aluminum substrate, 202, heat sink, 203, power device chip, 204, rectifier diode, 205, solder paste, 206, metal molding, 207, pin, 208, plastic packaging material, 209, resistor, 210, thin aluminum wire, 211, IC chip, 301, first contact portion, 302, second contact portion, 303, third contact portion, 304, molding body, 305, first through hole, 306, second through hole, 307, third through hole. DETAILED DESCRIPTION

[0035] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0036] The specific embodiments / examples described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention. They are illustrative and exemplary and should not be construed as limiting the embodiments of the present invention or the scope of the present invention. In addition to the examples described herein, those skilled in the art can also adopt other obvious technical solutions based on the claims and the disclosure of the specification. These technical solutions, including any obvious replacements and modifications of the embodiments described herein, are all within the scope of protection of the present invention.

[0037] Example 1

[0038] Please refer to Figure 1-3 As shown, Figure 1 Schematic diagram of the structure of the module of the present invention; Figure 2 Schematic diagram of the three-dimensional structure of the module of the present invention; Figure 3 The figure is a schematic diagram of the structure of the metal strip of the module of the present invention. The present invention provides a module, which includes: an aluminum substrate 201, a heat sink 202, a power device chip 203, a rectifier diode 204, a metal strip 206, a pin 207 and a plastic packaging material 208. The heat sink 202 is welded on the aluminum substrate 201. The bottom surface of the power device chip 203 is the source electrode, and the top surface of the power device chip 203 is the drain electrode. The source electrode is electrically connected to the heat sink 202, and the drain electrode is electrically connected to the metal strip 206. The back surface of the rectifier diode 204 is the cathode, and the front surface of the rectifier diode 204 is the anode. The cathode of the rectifier diode 204 is connected to the heat sink 202. The heat sink 202 is electrically connected to the source of the power device chip 203, and the positive electrode of the rectifier diode 204 is electrically connected to the drain of the power device chip 203 via the metal bead 206; the metal bead 206 is electrically connected to the power device chip 203, the rectifier diode 204 and the aluminum substrate 201 respectively; the pin 207 is used to connect to the circuit on the external electronic control board to connect the power supply to the power device chip 203 and transmit signals to the outside world; the heat sink 202, the power device chip 203, the rectifier diode 204 and the metal bead 206 are arranged in the plastic packaging material 208.

[0039] The metal strip 206 is made of a copper sheet with good electrical conductivity.

[0040] The heat sink 202, the power device chip 203, the rectifier diode 204, the metal layer 206 and the pins 207 are all provided in plurality. The pins 207 are provided in plurality and arranged side by side.

[0041] Specifically, the plastic packaging material 208 is used to install and set the heat sink 202, the power device chip 203, the rectifier diode 204 and the metal pressure strip 206, so as to isolate the components on the power module from the external environment and play a protective role. By welding the heat sink 202 to the aluminum substrate 201, the bottom surface of the power device chip 203 is the source, the front surface of the power device chip 203 is the drain, the source is electrically connected to the heat sink 202, and the drain is electrically connected to the metal bead 206; the back surface of the rectifier diode 204 is the negative electrode, the front surface of the rectifier diode 204 is the positive electrode, the negative electrode of the rectifier diode 204 is electrically connected to the source of the power device chip 203 through the heat sink 202, and the positive electrode of the rectifier diode 204 is electrically connected to the drain of the power device chip 203 through the metal bead 206; the metal bead 206 is electrically connected to the power device chip 203, the rectifier diode 204 and the aluminum substrate 201 respectively; the pin 207 is used to connect to the circuit on the external electronic control board to achieve electrical connection, so as to connect the power device chip 203 to the power supply and transmit signals to the outside world. In this way, by solidifying the metal strip 206 onto the surface of the power chip using the solder paste 205 reflow process, the chip surface will not be damaged, thereby improving product yield; the production line does not need a thick aluminum wire bonding machine, saving equipment costs; and thus improving production efficiency.

[0042] In this embodiment, the metal molding 206 includes a molding body 304, a first contact portion 301 protruding from the molding body 304 toward the direction of the aluminum substrate 201, a second contact portion 302 and a third contact portion 303, the first contact portion 301 is electrically connected to the drain of the power device chip 203, the second contact portion 302 is electrically connected to the positive pole of the rectifier diode 204, and the third contact portion 303 is electrically connected to the aluminum substrate 201. The pressure strip body 304 is used to cover the power device chip 203, the rectifier diode 204 and the aluminum substrate 201, and a first contact portion 301, a second contact portion 302 and a third contact portion 303 are provided on the pressure strip body 304 for soldering the solder paste 205 on the drain of the corresponding power device chip 203, the positive electrode of the rectifier diode 204 and the aluminum substrate 201, thereby achieving an electrical connection effect, facilitating electrical connection between the drain of the power device chip 203, the positive electrode of the rectifier diode 204 and the aluminum substrate 201, and facilitating conduction.

[0043] The pressure strip body 304 can also support the first contact portion 301 , the second contact portion 302 and the third contact portion 303 .

[0044] In this embodiment, the first contact portion 301 is soldered to the drain electrode of the power device chip 203 via solder paste 205, the second contact portion 302 is soldered to the anode electrode of the rectifier diode 204 via solder paste 205, and the third contact portion 303 is soldered to the aluminum substrate 201 via solder paste 205. Soldering with solder paste 205 facilitates curing after reflow, thereby achieving an electrical connection.

[0045] In this embodiment, the first contact portion 301 , the second contact portion 302 , and the third contact portion 303 are respectively provided with a first through hole 305 , a second through hole 306 , and a third through hole 307 formed therethrough.

[0046] Specifically, the first contact portion 301, the second contact portion 302, and the third contact portion 303 are penetrated to form a first through hole 305, a second through hole 306, and a third through hole 307. Since the center of the contact is a through hole, the contact area between the contact copper foil and the solder paste 205 can be increased, making the welding more secure.

[0047] In this embodiment, the first through hole 305 and the third through hole 307 are both square structures, and the second through hole 306 is circular structure. The through hole with square structure has a large welding cross-sectional area, and the through hole with circular structure has uniform force during welding.

[0048] In this embodiment, the first and second contact portions 301 and 302 have the same height relative to the beading body 304, while the third contact portion 303 has a greater height relative to the beading body 304 than the first and second contact portions 301 and 302. Because the power device chip 203 and the rectifier diode 204 are both mounted on the heat sink 202, which is mounted on the aluminum substrate 201, a gap is formed between the upper surface of the heat sink 202 and the upper surface of the aluminum substrate 201. By ensuring that the first and second contact portions 301 and 302 have the same height relative to the beading body 304 and that the third contact portion 303 has a greater height relative to the beading body 304 than the first and second contact portions 301 and 302, this allows for electrical connection between the drain solder joint of the power device chip 203, the positive solder joint of the rectifier diode 204, and the solder joint of the aluminum substrate 201.

[0049] In this embodiment, the module further includes a plurality of resistors 209 provided on the aluminum substrate 201, and the plurality of resistors 209 are electrically connected to the aluminum substrate 201. The plurality of resistors 209 protect the circuit and provide high safety.

[0050] In this embodiment, the module further includes a plurality of thin aluminum wires 210, which respectively connect the aluminum substrate 201 and the gate of the power device chip 203. The plurality of thin aluminum wires 210 are used to electrically connect the aluminum substrate 201 and the power device chip 203, and have a good conductive effect.

[0051] In this embodiment, one side of the aluminum substrate 201 is provided with circuit wiring, and the circuit wiring is provided with solder joints for mounting the heat sink 202, the pins 207, the plurality of thin aluminum wires 210, the driver IC chip 211 and the capacitance and resistance components.

[0052] Example 2

[0053] like Figure 1-4 ,in, Figure 1 Schematic diagram of the structure of the module of the present invention; Figure 2 Schematic diagram of the three-dimensional structure of the module of the present invention; Figure 3 This is a schematic structural diagram of the metal layer of the module of the present invention; Figure 4 The present invention also provides a method for manufacturing a module, which includes the following steps:

[0054] S1. Soft material welding: Heat the copper heat sink 202 to about 350°C in a nitrogen-protected environment, apply a layer of solder with a melting point of 330°C on the surface of the heat sink 202 , and mount the power device chip 203 and the rectifier diode 204 chip on the heat sink 202 .

[0055] S2. Solder paste printing: Apply solder paste 205 with a melting point of 220° C. to the location where the components are to be mounted on the aluminum substrate 201 .

[0056] S3, first SMT patch: mount the heat sink 202 components with power devices, capacitors, and resistors onto the heat sink 202.

[0057] S4, chip mounting: mounting the driver IC chip 211 on the aluminum substrate 201 .

[0058] S5. Tinning: spray tin paste 205 on the drain surface of the power device and the positive electrode surface of the rectifier diode 204.

[0059] S6. Second SMT patch: Install metal strip 206.

[0060] S7. Install pins: mount pins 207 onto corresponding solder joints on the aluminum substrate 201.

[0061] S8, reflow soldering: The product passes through a reflow furnace with a peak temperature set at 230° C. to solidify the power device chip 203 onto the aluminum substrate 201 and solidify the metal layer 206 onto the product.

[0062] S9. Thin aluminum wire welding: Weld aluminum wires with a diameter of 1.5 mil between the solder joints of the driver IC chip 211 and the solder joints of the aluminum substrate 201, and between the gate solder joints of the power device chip 203 and the solder joints of the aluminum substrate 201 to achieve electrical connection between them.

[0063] S10, injection molding and fixing: the product is encapsulated into the interior of the plastic packaging material by injection molding.

[0064] S11. Laser marking: marking product information on the outer shell of the product plastic packaging material.

[0065] S12, manufacturing and forming: punching and bending the pins 207 into a required shape.

[0066] Specifically, the copper heat sink 202 is heated to approximately 350°C in a nitrogen atmosphere, a layer of solder with a melting point of 330°C is applied to the surface of the heat sink 202, and the power device chip 203 and the rectifier diode 204 are mounted on the heat sink 202. A solder paste 205 with a melting point of 220°C is applied to the device mounting position on the aluminum substrate 201. The heat sink assembly with the power device mounted thereon, the capacitor, and the resistor are mounted on the heat sink 202. The driver IC is mounted on the aluminum substrate 201. Solder paste 205 is sprayed on the drain surface of the power device and the positive surface of the rectifier diode 204. The metal molding 206 is installed by soldering. The pins 207 are mounted on the corresponding solder joints of the aluminum substrate 201. The product is passed through a reflow oven with a peak temperature set at 230°C to solidify the power device chip 203 onto the aluminum substrate 201, and the metal molding 206 is solidified onto the product. A 1.5-mil diameter aluminum wire is welded between the solder joints of the driver IC chip 211 and the aluminum substrate 201, and between the gate solder joints of the power device chip 203 and the aluminum substrate 201, to achieve electrical connection. The product is encapsulated within the molding compound through injection molding. Product information is printed on the outer shell of the molding compound. The pins 207 are punched and bent into the desired shape. The metal bead 206 is cured onto the surface of the power chip using the solder paste 205 reflow process without damaging the chip surface, thereby improving product yield. The production line no longer requires a thick aluminum wire bonding machine, saving equipment costs and further improving production efficiency.

[0067] Compared with the related art, the present invention welds the heat sink onto the aluminum substrate, the bottom surface of the power device chip is the source electrode, the top surface of the power device chip is the drain electrode, the source electrode is electrically connected to the heat sink, and the drain electrode is electrically connected to the metal bead; the back surface of the rectifier diode is the negative electrode, the front surface of the rectifier diode is the positive electrode, the negative electrode of the rectifier diode is electrically connected to the source electrode of the power device chip via the heat sink, and the positive electrode of the rectifier diode is electrically connected to the drain electrode of the power device chip via the metal bead; the metal bead is electrically connected to the power device chip, the rectifier diode and the aluminum substrate respectively; the pin is used to connect to the circuit on the external electronic control board to connect the power device chip to the power supply and transmit signals to the outside world; the heat sink, the power device chip, the rectifier diode and the metal bead are arranged in the plastic packaging material; the metal bead is cured to the surface of the power chip by the solder paste reflow process without damaging the chip surface, which can improve the product yield; the production line does not require a thick aluminum wire bonding machine, saving equipment costs, and thus can improve production efficiency.

Claims

1. A module, characterized in that: include: An aluminum substrate, a heat sink, a power device chip, a rectifier diode, a metal bead, a pin, and a plastic packaging material. The heat sink is welded on the aluminum substrate. The bottom surface of the power device chip is the source electrode, and the top surface of the power device chip is the drain electrode. The source electrode is electrically connected to the heat sink, and the drain electrode is electrically connected to the metal bead. The back surface of the rectifier diode is the negative electrode, and the front surface of the rectifier diode is the positive electrode. The negative electrode of the rectifier diode is electrically connected to the source electrode of the power device chip via the heat sink, and the positive electrode of the rectifier diode is electrically connected to the drain electrode of the power device chip via the metal bead. The metal bead is electrically connected to the power device chip, the rectifier diode, and the aluminum substrate, respectively. The pin is used to connect to the circuit on the external electronic control board to connect the power device chip to the power supply and transmit signals to the outside world. The heat sink, the power device chip, the rectifier diode, and the metal bead are arranged in the plastic packaging material. The metal bead includes a bead body, a first contact portion, a second contact portion, and a third contact portion formed by the bead body protruding toward the aluminum substrate, wherein the first contact portion is electrically connected to the drain of the power device chip, the second contact portion is electrically connected to the anode of the rectifier diode, and the third contact portion is electrically connected to the aluminum substrate; The first contact portion is soldered to the drain of the power device chip via solder paste, the second contact portion is soldered to the anode of the rectifier diode via solder paste, and the third contact portion is soldered to the aluminum substrate via solder paste; The first contact portion and the second contact portion have the same height relative to the pressure strip body, and the third contact portion has a height relative to the pressure strip body greater than the first contact portion and the second contact portion. The module further comprises a plurality of thin aluminum wires, wherein the plurality of thin aluminum wires are respectively connected to the aluminum substrate and the gate of the power device chip; One side of the aluminum substrate is provided with a circuit wiring, and the circuit wiring is provided with solder joints for mounting the heat sink, the pins, the plurality of thin aluminum wires, the driver IC chip and the capacitance and resistance components.

2. The module according to claim 1, wherein The first contact portion, the second contact portion, and the third contact portion are respectively provided with a first through hole, a second through hole, and a third through hole formed therethrough.

3. The module according to claim 2, wherein The first through hole and the third through hole are both square structures, and the second through hole is a circular structure.

4. The module according to claim 1, wherein The module further includes a plurality of resistors disposed on the aluminum substrate, and the plurality of resistors are electrically connected to the aluminum substrate.

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