Heat dissipation structure of high-voltage-resistant high-power chip PIN diode and processing method of heat dissipation structure

Abstract

The invention relates to a heat dissipation structure of a high-voltage-resistant high-power chip PIN diode, which comprises a heat sink, a first PCB dielectric substrate which is arranged upwards, a first copper cushion block which is arranged upwards on the first PCB dielectric substrate, a diamond copper substrate which is arranged upwards on an aluminum nitride ceramic substrate, and a gasket and a PIN diode chip which are respectively arranged upwards on the diamond copper substrate, the gasket is in bonding connection with the first copper cushion block through a first gold wire; the second PCB dielectric substrate is upwards provided with a second copper cushion block, and the PIN diode chip is in bonding connection with the second copper cushion block through a second gold wire. The microwave module is small in size, small in height space requirement and capable of being popularized and used in a conventional microwave module, the large-power chip in a PIN diode flat packaging mode is selected, the size is small, the chip is thin and low in cost, the size can be made to be as small as possible under the condition that the heat dissipation requirement is met, the needed height space is small, and the microwave module can be popularized and used in the microwave module; and the situation that the heat dissipation structure is enlarged and cannot be applied to microwave modules with smaller and smaller volume requirements is avoided.

Description

Technical Field

[0001] This invention relates to the field of microelectronic heat dissipation technology, and in particular to a heat dissipation structure and processing method for a high-voltage, high-power chip PIN diode. Background Technology

[0002] High-power semiconductor transistors and microwave power devices generate a lot of heat when they are working. The accumulation of heat will cause the internal temperature of the circuit to rise. Without proper heat dissipation measures, excessively high temperatures will affect the performance of the components and may even cause the components to burn out.

[0003] Generally, the maximum allowable junction temperature for high-power semiconductor crystals and microwave power devices is 175°C, with a maximum allowable temperature rise of less than 100°C. Natural convection and radiation-driven air cooling are only effective when the maximum allowable temperature rise is 60°C and the heat flux density is less than 0.05 W / cm². When the maximum allowable temperature rise is 100°C, forced air cooling can provide heat transfer capacity with a heat flux density not exceeding 1 W / cm².

[0004] When the heat flux density of high-power chips exceeds 1 W / cm², heat dissipation methods such as microchannel cold plates, phase change heat transfer, and impingement jets are required. However, microchannel cold plates and impingement jets both require liquid cooling circulation systems, resulting in large volumes and high costs. Phase change heat transfer requires sufficiently large space for the phase change material and sufficiently high thermal conductivity, which is not feasible in microwave modules with increasingly smaller size requirements, and it also suffers from high costs.

[0005] Therefore, developing a heat dissipation structure that is not broken down by high voltage, does not burn out due to instantaneous high heat flux density, does not require a liquid cooling circulation system, and can be applied to miniaturized products without increasing volume has become an urgent technical problem to be solved. Summary of the Invention

[0006] To address the issues of existing high heat flux density heat dissipation methods requiring large, expensive liquid cooling systems that can withstand high-pressure shocks, the primary objective of this invention is to provide a small, low-cost solution that can achieve 2750 W / cm² heat flux density. 2 A heat dissipation structure for high-voltage, high-power PIN diodes that can withstand ultra-high thermal shock and operate safely for extended periods.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a heat dissipation structure for a high-voltage, high-power PIN diode, comprising a heat sink, a first PCB dielectric substrate, an aluminum nitride ceramic substrate, and a second PCB dielectric substrate disposed upwards on the heat sink, the first PCB dielectric substrate and the second PCB dielectric substrate being located on the left and right sides of the aluminum nitride ceramic substrate, respectively, with a gap between them; a first copper pad disposed upwards on the first PCB dielectric substrate, a diamond copper substrate disposed upwards on the aluminum nitride ceramic substrate, a pad and a PIN diode chip disposed upwards on the diamond copper substrate, with a gap between the pad and the PIN diode chip, the pad being bonded to the first copper pad by a first gold wire; a second copper pad disposed upwards on the second PCB dielectric substrate, the PIN diode chip being bonded to the second copper pad by a second gold wire.

[0008] Both the first PCB dielectric substrate and the second PCB dielectric substrate are fastened to the heat sink with screws; the first copper pad is soldered to the first PCB dielectric substrate with solder sheet; the second copper pad is soldered to the second PCB dielectric substrate with solder sheet.

[0009] The aluminum nitride ceramic substrate is soldered to the heat sink using tin solder sheets, the diamond copper substrate is soldered to the aluminum nitride ceramic substrate using gold solder sheets, the gasket is soldered to the diamond copper substrate using gold solder sheets, and the PIN diode chip is soldered to the diamond copper substrate using gold solder sheets.

[0010] The PIN diode chip includes a chip body and electrodes, and the electrodes are bonded to a second copper pad via a second gold wire.

[0011] Another object of the present invention is to provide a method for fabricating a heat dissipation structure for a high-voltage, high-power chip PIN diode, the method comprising the following sequential steps:

[0012] (1) Calculate the dimensions of the diamond copper substrate and aluminum nitride ceramic substrate required for heat dissipation of the PIN diode chip;

[0013] (2) The diamond copper substrate and aluminum nitride ceramic substrate that meet the heat dissipation requirements are coated with a surface treatment according to the welding requirements;

[0014] (3) Cut out the corresponding specifications of tin solder sheet, gold solder sheet, first copper pad, second copper pad and pad according to the required size;

[0015] (4) Lay gold-tin solder sheets on aluminum nitride ceramic substrate, then lay diamond copper substrate on gold-tin solder sheets, then lay gold-tin solder sheets on the corresponding positions of diamond copper substrate, then place PIN diode chip and pad on gold-tin solder sheets, and finally check that the position meets the requirements before vacuum brazing to obtain vacuum brazed chip set.

[0016] (5) Check the welding condition of the vacuum brazing chipset. After the welding quality is qualified, proceed to step (6).

[0017] (6) Lay solder sheets at the corresponding positions of the heat sink and then use the vacuum soldering process again to solder the vacuum soldering chipset onto the heat sink;

[0018] (7) The first copper pad is soldered onto the corresponding pad of the first PCB dielectric substrate using solder pads;

[0019] (8) Solder the second copper pad onto the corresponding pad of the second PCB dielectric substrate using solder pads;

[0020] (9) Secure the first PCB dielectric substrate to the heat sink with screws;

[0021] (10) Secure the second PCB dielectric substrate to the heat sink with screws;

[0022] (11) The second gold wire is bonded to the electrode of the PIN diode chip and the second copper pad using a gold wire bonding process;

[0023] (12) The first gold wire is bonded to the gasket and the first copper pad using a gold wire bonding process.

[0024] As can be seen from the above technical solution, the beneficial effects of the present invention are as follows: First, the present invention achieves high heat flux density heat dissipation for high-power chips, and can withstand instantaneous heat flux density of up to 2750W / cm². 2 It withstands ultra-high thermal shock and can operate safely for extended periods without being burned out by heat, solving the problem of high-power chips withstanding temperatures exceeding 1W / cm². 2 First, this invention addresses the challenge of high heat flux density heat dissipation, which can lead to burnout during thermal shock. Second, it withstands thousands of volts of high voltage without breakdown, ensuring that the high-power chip can dissipate heat effectively and operate stably under high voltage conditions. Third, it is small in size and requires minimal height space, enabling its widespread use in conventional microwave modules. The high-power chip, using a PIN diode flat package, is small and thin, minimizing its size while meeting heat dissipation requirements. This allows for widespread use in microwave modules without increasing product size, avoiding the limitation of larger heat dissipation structures in increasingly smaller microwave modules. Fourth, it is low-cost and economically efficient, avoiding the use of microchannel cold plates, impingement jets, and phase-change cooling methods. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention;

[0026] Figure 2for Figure 1 A schematic diagram of the structure of a PIN diode chip. Detailed Implementation

[0027] like Figure 1 As shown, a heat dissipation structure for a high-voltage, high-power PIN diode includes a heat sink 1. A first PCB dielectric substrate 10, an aluminum nitride ceramic substrate 3, and a second PCB dielectric substrate 11 are respectively disposed upwards on the heat sink 1. The first PCB dielectric substrate 10 and the second PCB dielectric substrate 11 are located on the left and right sides of the aluminum nitride ceramic substrate 3, respectively, with a gap between them. A first copper pad 9 is disposed upwards on the first PCB dielectric substrate 10. A diamond copper substrate 8 is disposed upwards on the aluminum nitride ceramic substrate 3. A pad 12 and a PIN diode chip 6 are respectively disposed upwards on the diamond copper substrate 8. A gap exists between the pad 12 and the PIN diode chip 6. The pad 12 is bonded to the first copper pad 9 via a first gold wire 13. A second copper pad 4 is disposed upwards on the second PCB dielectric substrate 11. The PIN diode chip 6 is bonded to the second copper pad 4 via a second gold wire 5.

[0028] The first PCB dielectric substrate 10 and the second PCB dielectric substrate 11 are both fastened to the heat sink 1 by screws; the first copper pad 9 is soldered to the first PCB dielectric substrate 10 by solder sheet 2; the second copper pad 4 is soldered to the second PCB dielectric substrate 11 by solder sheet 2.

[0029] The aluminum nitride ceramic substrate 3 is soldered to the heat sink 1 by solder sheet 2, the diamond copper substrate 8 is soldered to the aluminum nitride ceramic substrate 3 by solder sheet 7, the gasket 12 is soldered to the diamond copper substrate 8 by solder sheet 7, and the PIN diode chip 6 is soldered to the diamond copper substrate 8 by solder sheet 7.

[0030] like Figure 2 As shown, the PIN diode chip 6 includes a chip body 6a and an electrode 6b, and the electrode 6b is bonded to the second copper pad 4 through a second gold wire 5.

[0031] This method includes the following steps in sequence:

[0032] (1) Calculate the dimensions of the diamond copper substrate and aluminum nitride ceramic substrate 3 required for heat dissipation of the PIN diode chip 6;

[0033] (2) The diamond copper substrate and aluminum nitride ceramic substrate 3 that meet the heat dissipation requirements are coated with a surface treatment according to the welding requirements;

[0034] (3) Cut out the corresponding specifications of tin solder sheet 2, gold solder sheet 7, first copper pad 9, second copper pad 4 and pad 12 according to the required size;

[0035] (4) Lay gold-tin solder sheet 7 on aluminum nitride ceramic substrate 3, then lay diamond copper substrate on gold-tin solder sheet 7, then lay gold-tin solder sheet 7 on the corresponding position of diamond copper substrate, then place PIN diode chip 6 and pad 12 on gold-tin solder sheet 7, and finally check that the position meets the requirements before vacuum brazing to obtain vacuum brazed chip group;

[0036] (5) Check the welding condition of the vacuum brazing chipset. After the welding quality is qualified, proceed to step (6).

[0037] (6) Lay solder sheet 2 at the corresponding position of heat sink 1, and use vacuum brazing process again to solder the vacuum brazing chip set onto heat sink 1;

[0038] (7) The first copper pad 9 is soldered onto the corresponding pad of the first PCB dielectric substrate 10 using solder pad 2;

[0039] (8) The second copper pad 4 is soldered onto the corresponding pad of the second PCB dielectric substrate 11 using solder pad 2;

[0040] (9) Secure the first PCB dielectric substrate 10 to the heat sink 1 with screws;

[0041] (10) Secure the second PCB dielectric substrate 11 to the heat sink 1 with screws;

[0042] (11) The second gold wire 5 is bonded to the electrode of the PIN diode chip 6 and the second copper pad 4 using a gold wire bonding process;

[0043] (12) The first gold wire 13 is bonded to the pad 12 and the first copper pad 9 using a gold wire bonding process.

[0044] In summary, this invention achieves high heat flux density heat dissipation for high-power chips, capable of withstanding instantaneous heat flux densities up to 2750 W / cm². 2 It withstands ultra-high thermal shock and can operate safely for extended periods without being burned out by heat, solving the problem of high-power chips withstanding temperatures exceeding 1W / cm². 2This invention addresses the challenge of high heat flux density heat dissipation, which can lead to burn-out during thermal shock. It can withstand thousands of volts of high voltage without breakdown, enabling high-power chips to dissipate heat effectively and operate stably under high voltage conditions. The invention is small in size and requires minimal height space, allowing for widespread use in conventional microwave modules. Utilizing a PIN diode flat package, the high-power chip is small and thin, minimizing the required size and height while meeting heat dissipation needs. This allows for widespread use in microwave modules without increasing product size, avoiding the limitations of increasingly smaller modules where larger heat dissipation structures are unsuitable. Furthermore, it is low-cost and economically efficient, avoiding the use of microchannel cold plates, impingement jets, and phase-change cooling methods.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A heat dissipation structure for a high-voltage, high-power PIN diode, characterized in that: The device includes a heat sink, on which a first PCB dielectric substrate, an aluminum nitride ceramic substrate, and a second PCB dielectric substrate are respectively disposed upwards. The first PCB dielectric substrate and the second PCB dielectric substrate are located on the left and right sides of the aluminum nitride ceramic substrate, respectively, and there is a gap between the three. A first copper pad is disposed upwards on the first PCB dielectric substrate, and a diamond copper substrate is disposed upwards on the aluminum nitride ceramic substrate. A pad and a PIN diode chip are disposed upwards on the diamond copper substrate, respectively. There is a gap between the pad and the PIN diode chip. The pad is bonded to the first copper pad by a first gold wire. The second PCB dielectric substrate has a second copper pad facing upwards, and the PIN diode chip is bonded to the second copper pad through a second gold wire.

2. The heat dissipation structure of the high-voltage, high-power chip PIN diode according to claim 1, characterized in that: Both the first PCB dielectric substrate and the second PCB dielectric substrate are fastened to the heat sink with screws; the first copper pad is soldered to the first PCB dielectric substrate with solder sheet; the second copper pad is soldered to the second PCB dielectric substrate with solder sheet.

3. The heat dissipation structure of the high-voltage, high-power chip PIN diode according to claim 1, characterized in that: The aluminum nitride ceramic substrate is soldered to the heat sink using tin solder sheets, the diamond copper substrate is soldered to the aluminum nitride ceramic substrate using gold solder sheets, the gasket is soldered to the diamond copper substrate using gold solder sheets, and the PIN diode chip is soldered to the diamond copper substrate using gold solder sheets.

4. The heat dissipation structure of the high-voltage, high-power chip PIN diode according to claim 1, characterized in that: The PIN diode chip includes a chip body and electrodes, and the electrodes are bonded to a second copper pad via a second gold wire.

5. A method for fabricating a heat dissipation structure for a high-voltage, high-power PIN diode according to any one of claims 1 to 4, characterized in that: The method includes the following steps in sequence: (1) Calculate the dimensions of the diamond copper substrate and aluminum nitride ceramic substrate required for heat dissipation of the PIN diode chip; (2) The diamond copper substrate and aluminum nitride ceramic substrate that meet the heat dissipation requirements are coated with a surface treatment according to the welding requirements; (3) Cut out the corresponding specifications of tin solder sheet, gold solder sheet, first copper pad, second copper pad and pad according to the required size; (4) Lay gold-tin solder sheets on aluminum nitride ceramic substrate, then lay diamond copper substrate on gold-tin solder sheets, then lay gold-tin solder sheets on the corresponding positions of diamond copper substrate, then place PIN diode chip and pad on gold-tin solder sheets, and finally check that the position meets the requirements before vacuum brazing to obtain vacuum brazed chip set. (5) Check the welding condition of the vacuum brazing chipset. After the welding quality is qualified, proceed to step (6). (6) Lay solder sheets at the corresponding positions of the heat sink and then use the vacuum soldering process again to solder the vacuum soldering chipset onto the heat sink; (7) The first copper pad is soldered onto the corresponding pad of the first PCB dielectric substrate using solder pads; (8) Solder the second copper pad onto the corresponding pad of the second PCB dielectric substrate using solder pads; (9) Secure the first PCB dielectric substrate to the heat sink with screws; (10) Secure the second PCB dielectric substrate to the heat sink with screws; (11) The second gold wire is bonded to the electrode of the PIN diode chip and the second copper pad using a gold wire bonding process; (12) The first gold wire is bonded to the gasket and the first copper pad using a gold wire bonding process.

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