Packaging structure of gallium nitride chip in power module

Abstract

The utility model relates to the technical field of power devices, in particular to a packaging structure of a gallium nitride chip in a power module, which comprises a packaging shell. The packaging shell is in the shape of a long cube; a plurality of silicon nitride copper-coated ceramic substrates are distributed in the packaging shell along the long axis direction; a plurality of devices are arranged on the silicon nitride copper-coated ceramic substrate; and the plurality of silicon nitride copper-coated ceramic substrates are connected through bonding wires. Aiming at the problem of poor heat dissipation effect of a frame structure in the prior art, a plurality of silicon nitride copper-coated ceramic substrates are designed according to power partitions of devices to respectively bear power devices and are connected through bonding wires. Because the silicon nitride copper-clad ceramic substrate has better temperature resistance and thermal conductivity, a better heat dissipation effect on the power device can be realized, and meanwhile, the silicon nitride copper-clad ceramic substrate is not easy to deform under the sectional design, so that the reliability of the device is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to power device technical field, concretely relates to a kind of packaging structure of gallium nitride chip in power module. BACKGROUND

[0002] Power module belongs to a kind of power driver that fuses power electronics and integrated circuit technology each other.It is with high integration, high reliability and many advantages, so that the share of power module in market is more and more big.The device is especially suitable for driving motor's frequency converter and various inverter power supply, has become the power electronic device commonly used in the field of frequency conversion, metallurgical machinery, electric traction, servo drive and variable-frequency household appliance.Gallium nitride chip is a kind of direct bandgap semiconductor.The energy gap of gallium nitride is 3.4eV, can be used in high-power, high-speed optoelectronic element, and gallium nitride has excellent electron mobility and electron saturation drift speed, which makes it have excellent performance in radio frequency and microwave electronic devices.Therefore, to realize better output performance, gallium nitride chip is often applied in power circuit scene in prior art, and packaging device is made based on gallium nitride chip, and then used in various electronic circuits.

[0003] For example, Chinese patent CN202210781961.5 discloses a gallium nitride power chip heat dissipation structure, which includes a plurality of gallium nitride chips, a chip gate, a chip source, a chip drain and a chip substrate arranged on each of the plurality of gallium nitride chips, a heat dissipation module located on both sides of the plurality of gallium nitride chips, and a plurality of bus driving capacitors located in the heat dissipation module. The heat dissipation module realizes double-sided heat dissipation of the plurality of gallium nitride chips. Compared with single-sided heat dissipation of gallium nitride, the maximum temperature inside the gallium nitride chip can be reduced under normal working and heat dissipation conditions. At the same time, the electrical connection between the heat dissipation modules is used to optimize the power loop and the structure design of the double-insulation three-conductor structure, so that the mutual inductance magnetic flux of the loop is canceled out. Compared with conventional wire bonding, the power loop inductance can be reduced.

[0004] However, in actual implementation process, the inventor found that in prior art, the gallium nitride chip is usually mounted on a frame base island with an ordinary substrate. Due to the increase of power density and high-frequency characteristics of the gallium nitride chip, the overall chip generates a lot of heat, and the heat dissipation effect is not good, which affects the reliability of the product. UTILITY MODEL CONTENT

[0005] In view of the above problems existing in the prior art, a packaging structure of gallium nitride chip in power module is provided.

[0006] The specific technical solutions are as follows:

[0007] A packaging structure of a gallium nitride chip in a power module comprises a packaging shell;

[0008] The packaging shell is in the shape of a long cuboid;

[0009] In the packaging shell, a plurality of silicon nitride copper-clad ceramic substrates are distributed along the direction of the long axis;

[0010] A plurality of devices are arranged on the silicon nitride copper-clad ceramic substrates;

[0011] The silicon nitride copper-clad ceramic substrates are connected by bonding wires.

[0012] On the other hand, a nickel-plated copper substrate for heat dissipation is arranged in the packaging shell;

[0013] The lower surface of the nickel-plated copper substrate for heat dissipation is fixedly connected to the packaging shell;

[0014] The upper surface of the nickel-plated copper substrate for heat dissipation is respectively welded with the silicon nitride copper-clad ceramic substrates.

[0015] On the other hand, a snap ring is distributed at the four corners of the packaging shell;

[0016] The nickel-plated copper substrate for heat dissipation is fixed on the packaging shell by the snap ring.

[0017] On the other hand, the silicon nitride copper-clad ceramic substrates are welded on the upper surface of the nickel-plated copper substrate for heat dissipation by tin-antimony solder.

[0018] On the other hand, the number of the silicon nitride copper-clad ceramic substrates is three;

[0019] Six rectifier chips and two gallium nitride chips are arranged on the first silicon nitride copper-clad ceramic substrate;

[0020] Eight gallium nitride chips are arranged on the second silicon nitride copper-clad ceramic substrate;

[0021] Two gallium nitride chips, one thermistor, one braking IGBT chip and one braking diode chip are arranged on the third silicon nitride copper-clad ceramic substrate.

[0022] On the other hand, a terminal is arranged on the packaging shell;

[0023] The silicon nitride copper-clad ceramic substrates are bonded to the terminal by 16 mil soft aluminum wires;

[0024] The gallium nitride chips are bonded to the silicon nitride copper-clad ceramic substrates by 1.5 mil copper wires;

[0025] The rectifier chips are bonded to the silicon nitride copper-clad ceramic substrates by 16 mil soft aluminum wires;

[0026] The braking IGBT chip is bonded to the silicon nitride copper-clad ceramic substrate by a 16 mil soft aluminum wire;

[0027] The braking diode chip is bonded to the silicon nitride copper-clad ceramic substrate by a 16 mil soft aluminum wire.

[0028] On the other hand, the upper part of the silicon nitride copper-clad ceramic substrate is fixed by pouring silica gel.

[0029] On the other hand, it also includes an upper cover;

[0030] The upper cover cooperates with the packaging shell to wrap the internal silicon nitride copper-clad ceramic substrate.

[0031] The above technical solution has the following advantages or beneficial effects:

[0032] In view of the poor heat dissipation effect of the frame structure in the prior art, in the present scheme, a plurality of silicon nitride copper-clad ceramic substrates are designed to carry power devices according to power partition of the device, and are connected by bonding wires. Since the silicon nitride copper-clad ceramic substrate has better temperature resistance and thermal conductivity, it can achieve good heat dissipation effect for the power device, and at the same time, the segmented design of the silicon nitride copper-clad ceramic substrate is not easy to deform, improving the reliability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0033] Reference will be made to the accompanying drawings to more fully describe the embodiments of the present application. However, the accompanying drawings are only used for illustration and explanation, and do not constitute a limitation on the scope of the present application.

[0034] Figure 1 It is a whole schematic diagram of the embodiment of the present application;

[0035] Figure 2 It is a schematic diagram of the upper cover of the embodiment of the present application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0037] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0038] The present application will be further described below in combination with the drawings and specific embodiments, but it is not limited by the present application.

[0039] The utility model discloses a package structure of gallium nitride chip in power module,

[0040] A kind of gallium nitride chip in power module is packaged as shown in Figure Figure 1 、 Figure 2 Including package shell 1;

[0041] Package shell 1 is long cuboid;

[0042] In package shell 1, along long axis direction distribution has multiple silicon nitride copper clad ceramic substrate 2;

[0043] Multiple devices 3 are provided on silicon nitride copper clad ceramic substrate 2;

[0044] Multiple silicon nitride copper clad ceramic substrate 2 are connected by bonding wire.

[0045] Specifically, for the problem that the frame structure in the prior art has poor heat dissipation effect, in the scheme, multiple silicon nitride copper clad ceramic substrates 2 are designed to carry power devices according to the power partition of the device, and are connected by bonding wires. Since the silicon nitride copper clad ceramic substrate 2 has better temperature resistance and thermal conductivity, it can achieve good heat dissipation effect for the power device, and at the same time, the silicon nitride copper clad ceramic substrate 2 is not easy to deform under the segmented design, improving the reliability of the device 3.

[0046] Among them, silicon nitride copper clad ceramic substrate 2 is a bare board formed based on the ceramization of silicon nitride material, and a material formed by welding copper foil. Based on the copper foil on the substrate, better thermal conductivity can be achieved, and at the same time, after the ceramization treatment of the silicon nitride material, it has high hardness and heat resistance. When the power device above heats up, the heat can be quickly dispersed based on the copper foil and introduced into the silicon nitride ceramic plate material below. Since the silicon nitride ceramic plate material expands less under heat, and is preliminarily heat-treated through the copper foil, the material is not easy to deform, affecting the overall stability.

[0047] Correspondingly, considering the different power areas on the device, in the scheme, the silicon nitride copper clad ceramic substrate 2 is also split into three pieces according to different chip function areas, and the three pieces have different expansion degrees, thereby avoiding the distortion problem caused by uneven heating of the silicon nitride copper clad ceramic substrate 2.

[0048] In one embodiment, package shell 1 is also provided with a heat dissipation nickel-plated copper substrate 4;

[0049] The lower surface of the heat dissipation nickel-plated copper substrate 4 is fixedly connected with the package shell 1;

[0050] The upper surface of the heat dissipation nickel-plated copper substrate 4 is respectively welded with the silicon nitride copper clad ceramic substrate 2.

[0051] Specifically, to further achieve better heat dissipation efficiency, the packaging shell 1 is further provided with a heat dissipation nickel-plated copper substrate 4 in the embodiment.

[0052] The nickel-plated copper substrate 4 is a substrate that is further plated with nickel on the basis of a copper substrate to improve the heat conductivity. The silicon nitride-coated copper ceramic substrate 2 is welded on the substrate to conduct heat through the welding surface.

[0053] When the power device is working, the heat is first conducted to the silicon nitride-coated copper ceramic substrate 2, and then conducted to the nickel-plated copper substrate 4 through the contact surface, and then conducted out of the packaging shell 1 through the nickel-plated copper substrate 4. In actual use, a heat sink is often attached to the outside of the packaging shell 1 or immersed in a cooling liquid to achieve heat dissipation.

[0054] In one embodiment, the packaging shell 1 is provided with a clamping ring 5 at four corners;

[0055] The heat dissipation nickel-plated copper substrate 4 is fixed on the packaging shell through the clamping ring 5.

[0056] Specifically, to achieve better fixing effect, the packaging shell 1 is provided with a clamping ring 5 at four corners in the embodiment, and the heat dissipation nickel-plated copper substrate 4 is provided with an inner fillet groove at the corresponding position. The radius of the inner fillet groove is slightly larger than the radius of the clamping ring 5, so that the clamping ring 5 is fixed by interference fit when assembled.

[0057] In one embodiment, the silicon nitride-coated copper ceramic substrate 2 is welded on the upper surface of the heat dissipation nickel-plated copper substrate 4 by tin-antimony solder.

[0058] Specifically, to achieve better heat conduction effect, the silicon nitride-coated copper ceramic substrate 2 is welded on the upper surface of the heat dissipation nickel-plated copper substrate 4 by tin-antimony solder in the embodiment, so as to achieve better heat conduction while ensuring firm welding.

[0059] In one embodiment, the number of silicon nitride-coated copper ceramic substrates 2 is three;

[0060] The first silicon nitride-coated copper ceramic substrate is provided with 6 rectifier chips and 2 gallium nitride chips;

[0061] The second silicon nitride-coated copper ceramic substrate is provided with 8 gallium nitride chips;

[0062] The third silicon nitride-coated copper ceramic substrate is provided with 2 gallium nitride chips, one thermistor, one braking IGBT chip and one braking diode chip.

[0063] Specifically, to achieve better power distribution, in the embodiment, the silicon nitride copper clad ceramic substrate 2 is divided into three pieces according to different chip functional areas, and different numbers and functions of devices are arranged on each piece. The heat generation power of each piece is different, thereby avoiding the problem of distortion caused by uneven heating on the large silicon nitride copper clad ceramic substrate 2.

[0064] In one embodiment, the packaging shell 1 is provided with terminals 6;

[0065] The silicon nitride copper clad ceramic substrate 2 is bonded to the terminals by 16 mil soft aluminum wires;

[0066] The gallium nitride chip is bonded to the silicon nitride copper clad ceramic substrate 2 by 1.5 mil copper wires;

[0067] The rectifier chip is bonded to the silicon nitride copper clad ceramic substrate 2 by 16 mil soft aluminum wires;

[0068] The braking IGBT chip is bonded to the silicon nitride copper clad ceramic substrate 2 by 16 mil soft aluminum wires;

[0069] The braking diode chip is bonded to the silicon nitride copper clad ceramic substrate 2 by 16 mil soft aluminum wires.

[0070] Specifically, to achieve better heat output effect, in the embodiment, on the basis of arranging the printed circuit in the silicon nitride copper clad ceramic substrate 2, each device is inverted, that is, inverted on the silicon nitride copper clad ceramic substrate 2, the end face of the device is welded and fixed to the silicon nitride copper clad ceramic substrate 2, and the pin is upwardly led out by using the corresponding power specification bonding wire, thereby enabling the heat generation of the device to be directly led out to the silicon nitride copper clad ceramic substrate 2. In one embodiment, it also includes an upper cover 7;

[0071] The upper cover 7 cooperates with the packaging shell 1 to wrap the internal silicon nitride copper clad ceramic substrate 2.

[0072] Specifically, after the above assembly and bonding process is implemented, the upper cover 7 is covered on the packaging shell 1 to form a complete package wrapping the internal silicon nitride copper clad ceramic substrate 2 and the devices.

[0073] In one embodiment, the upper part of the silicon nitride copper clad ceramic substrate 2 is filled with silica gel for fixation.

[0074] Specifically, to achieve better device firmness, in the embodiment, before the upper cover 7 is closed, silica gel is injected into the remaining cavity in the packaging shell 1 and solidified, thereby fixing the internal devices and bonding wires.

[0075] The above merely describes preferred embodiments of the present application, and is not intended to limit the implementation and protection scope of the present application. For those skilled in the art, it should be understood that any equivalent substitutions and obvious changes made according to the content of the present application and drawings should be included in the protection scope of the present application.

Claims

1. A gallium nitride chip packaging structure in a power module, characterized in that, Including the packaging housing; The encapsulation shell is elongated cubic in shape; The encapsulation housing contains multiple silicon nitride copper-clad ceramic substrates distributed along the long axis. Multiple devices are disposed on the silicon nitride copper-clad ceramic substrate; Multiple silicon nitride copper-clad ceramic substrates are connected by bonding wires.

2. The packaging structure according to claim 1, characterized in that, The encapsulation housing is also provided with a heat-dissipating nickel-plated copper substrate. The lower surface of the heat-dissipating nickel-plated copper substrate is fixedly connected to the packaging shell; The upper surface of the heat-dissipating nickel-plated copper substrate is respectively welded with the silicon nitride copper-clad ceramic substrate.

3. The packaging structure according to claim 2, characterized in that, The four corners of the encapsulation housing are provided with retaining rings; The heat-dissipating nickel-plated copper substrate is fixed to the packaging housing by the retaining ring.

4. The packaging structure according to claim 2, characterized in that, The silicon nitride copper-clad ceramic substrate is soldered to the upper surface of the heat-dissipating nickel-plated copper substrate using tin-antimony solder.

5. The packaging structure according to claim 1, characterized in that, The number of silicon nitride copper-clad ceramic substrates is three; Six rectifier chips and two gallium nitride chips are disposed on the first silicon nitride copper-clad ceramic substrate; Eight gallium nitride chips are disposed on the second silicon nitride copper-clad ceramic substrate; Two gallium nitride chips, a thermistor, a braking IGBT chip, and a braking diode chip are disposed on the third silicon nitride copper-clad ceramic substrate.

6. The packaging structure according to claim 5, characterized in that, The encapsulation housing is provided with terminals; The silicon nitride copper-clad ceramic substrate is bonded to the terminal via 16mil soft aluminum wire; The gallium nitride chip is bonded to the silicon nitride copper-clad ceramic substrate via a 1.5mil copper wire; The rectifier chip is bonded to the silicon nitride copper-clad ceramic substrate via 16mil soft aluminum wires; The braking IGBT chip is bonded to the silicon nitride copper-clad ceramic substrate via 16mil soft aluminum wires; The braking diode chip is bonded to the silicon nitride copper-clad ceramic substrate via 16mil soft aluminum wire.

7. The packaging structure according to claim 1, characterized in that, Silicone is potted and fixed on the top of the silicon nitride copper-clad ceramic substrate.

8. The packaging structure according to claim 1, characterized in that, Also includes the top cover; The top cover and the encapsulation housing cooperate to enclose the internal silicon nitride copper-clad ceramic substrate.

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