A press-fit mounting structure

Abstract

The present application relates to the technical fields of semiconductor power device package testing and aerospace power supply high reliability application. The present application discloses a crimping type mounting structure, which comprises a frame mounted on a PCB and a buckle plate detachably connected with the frame, and a chip is mounted on the drain line area of the PCB; the frame is provided with a gate slot, a source slot, and a plurality of gate lead-out ends one and two and source lead-out ends one and two for electrically contacting with the PCB lines of the PCB; the buckle plate is internally integrated with a buckle plate gate lead-out end electrically connected with the gate slot and a buckle plate source lead-out end electrically connected with the source slot. The present application can realize vertical interconnection without sintering and wire bonding, greatly reducing the parasitic inductance caused by wire bonding process; support lossless and rapid replacement of bare chips, improve the screening and testing efficiency of high-value radiation-resistant devices and the partial maintainability of modules; adapt to multi-size radiation-resistant power MOSFET bare chips, and have good universality and aerospace-level environmental adaptability.

Description

Technical Field

[0001] This invention relates to the fields of semiconductor power device packaging and testing and high-reliability application technology in aerospace power supplies. In particular, it relates to a press-fit mounting structure for high-value switching devices such as radiation-resistant power MOSFETs, which is suitable for rapid verification and maintainable installation of power devices in aerospace power supplies and high-reliability scenarios. Background Technology

[0002] Radiation-resistant power MOSFETs are core power devices in high-radiation environments such as aerospace power supplies. Their electrical performance and reliability directly determine the efficiency, stability, and lifespan of the power system. Currently, complete systems are developing towards miniaturization, low loss, high frequency, and high reliability, placing stringent requirements on the parasitic parameters of power device packaging, testability, and maintainability.

[0003] The current mounting and testing of radiation-hardened power MOSFET bare cores mainly adopts the SIP+sintering wire bonding scheme: the drain (D) on the back of the bare core is sintered onto a metal substrate or PCB, and the source (S) and gate (G) on the front are interconnected to the PCB pads via wire bonding. This technology has the following core defects: 1. Excessive parasitic inductance degrades power conversion efficiency and exacerbates electromagnetic interference under high-frequency and high-power conditions, failing to meet the design goals of low noise and low loss for aerospace power supplies; 2. Testing and replacement costs are high. Sintering and bonding are irreversible connection processes. When testing and verifying high-value chips, replacing bare dies of different batches / specifications requires disassembling the original structure, which can easily cause damage to the bare die, substrate and surrounding devices. The testing cycle is long and the scrap rate is high. 3. Due to its manufacturing process, SIP packaged power supplies have poor maintainability. If individual components within the module fail, the entire module must be replaced, resulting in extremely high maintenance costs. 4. Poor structural compatibility: Different sized bare chips require customized sintering substrates and bonding schemes, resulting in poor versatility and difficulty in supporting rapid iterative verification of multiple chip models. Summary of the Invention

[0004] The purpose of this invention is to provide a press-fit mounting structure that solves the technical problems existing in the bare-chip mounting and testing of radiation-resistant power MOSFETs, such as large parasitic parameters, low testing efficiency, and the inability to disassemble and replace high-value chips during application verification and use.

[0005] To address the aforementioned technical problems, this invention provides a press-fit mounting structure, comprising a frame mounted on a PCB board and a snap-fit ​​plate detachably connected to the frame. A chip is mounted on the drain circuit area of ​​the PCB board. The frame is provided with a gate slot, a source slot, and multiple gate leads (one, two, one, and two) for electrical contact with the PCB board circuitry. The snap-fit ​​plate integrates a snap-fit ​​gate lead electrically connected to the gate slot and a snap-fit ​​source lead electrically connected to the source slot. The snap-fit ​​gate lead is connected to multiple gate pins via gate conductive posts, and the snap-fit ​​source lead is connected to multiple source pins via source conductive posts. The lower ends of the gate pins and source pins form elastic press-fit contacts with the gate electrode and source electrode of the chip, respectively. When the snap-fit ​​plate is snapped into place with the frame, the snap-fit ​​gate lead and the snap-fit ​​source lead are inserted into the gate slot and source slot of the frame, respectively, to form electrical contacts.

[0006] The buckle plate is connected to the frame by fixing screw one, fixing screw two, fixing screw three, and fixing screw four.

[0007] The frame and the buckle are both made of epoxy resin insulating material, and the buckle gate lead, buckle source lead, gate conductive pillar, source conductive pillar, gate slot, and source slot are all made of oxygen-free copper material.

[0008] Both the gate pin and the source pin are elastic pins with a two-section spring-loaded structure.

[0009] The PCB board circuitry is used to carry the chip and achieve electrical connections.

[0010] The frame is also provided with multiple threaded holes.

[0011] The drain of the chip is attached to the corresponding drain circuit area on the PCB board with conductive adhesive to form an electrical path.

[0012] The ends of the gate pin and source pin that contact the chip are made of pure gold.

[0013] Compared with existing technologies, this invention can achieve vertical interconnection without sintering and wire bonding, significantly reducing the parasitic inductance caused by wire bonding processes; it supports non-destructive and rapid replacement of bare cores, improving the screening and testing efficiency of high-value radiation-resistant devices and the partial maintainability of modules; it is compatible with bare cores of various sizes of radiation-resistant power MOSFETs, and has good versatility and aerospace-grade environmental adaptability.

[0014] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0016] Fig. 1 This is a schematic diagram of the structure of the present invention; Fig. 2 This is a cross-sectional view of the present invention; Fig. 3 This is a perspective view of the top of the invention.

[0017] In the diagram: 1-PCB board, 2-PCB board circuit, 3-frame, 4-clasp, 5-fixing screw one, 6-fixing screw two, 7-chip, 8-gate pin, 9-source pin, 10-gate conductive post, 11-source conductive post, 12-clasp gate lead, 13-clasp source lead, 14-gate lead one, 15-source lead one, 16-gate lead two, 17-source lead two, 18-fixing screw three, 19-fixing screw four. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of this invention. The embodiments can be combined with and referenced by each other without contradiction.

[0019] Example 1 like Figs. 1-3 The diagram shows a press-fit mounting structure, which is mounted on a PCB board 1. It mainly consists of two independent components: a frame 3 and a clip plate 4. The frame 3 and the clip plate 4 are detachably connected by fixing screws (fixing screw 1 5, fixing screw 2 6, fixing screw 3 18, and fixing screw 4 19). The whole structure realizes the electrical interconnection between the gate, source, and drain of the chip 7 and the PCB board circuit 2, and is suitable for the mounting, testing, and use of aerospace-grade radiation-resistant power MOSFET bare chips.

[0020] Specifically, the two major components, frame 3 and buckle 4, should be installed on PCB board 1 for use, with the purpose of bringing out the gate, source, and drain terminals of chip 7 to the circuit 2 on PCB board.

[0021] Specifically, the main body of frame 3 is made of epoxy resin insulating material (providing insulation capability and mechanical structural stability). It has a gate slot, a source slot and threaded holes for matching fixing screws. It integrates gate leads (gate lead one 14, gate lead two 16) and source leads (source lead one 15, source lead two 17). Both the gate leads and the source leads are made of oxygen-free copper tin-plated material (to prevent oxidation of the leads before use, and at the same time not to affect the soldering during use). It passes through PCB board 1 and is soldered on the back to fix and electrically connect frame 3 to PCB board 1.

[0022] Furthermore, the frame 3 is mounted on the PCB board 1 with the circuit already laid out via the gate leads (gate lead one 14, gate lead two 16) and the source leads (source lead one 15, source lead two 17); the PCB board circuit 2 is matched with the positions of the gate leads (gate lead one 14, gate lead two 16), the source leads (source lead one 15, source lead two 17) and the drain on the back of the chip 7.

[0023] Specifically, the main body of the buckle plate 4 is made of epoxy resin insulating material, and it integrates buckle plate gate lead-out terminal 12, buckle plate source lead-out terminal 13, gate conductive pillar 10, source conductive pillar 11, gate pin 8, and source pin 9. Buckle plate gate lead-out terminal 12 and buckle plate source lead-out terminal 13 can be inserted into the gate slot 20 and source slot 21 of the frame 3 to achieve electrical interconnection between the two.

[0024] Furthermore, the gate pin 8 and source pin 9 are two-section spring pins with compression capability. When compressed, they can provide spring force to the chip 7. The part of the pin that contacts the chip 7 is made of pure gold material to avoid scratching the chip 7 due to excessive hardness. After the buckle plate 4 and the frame 3 are fastened together, the gate pin 8 and source pin 9 are in close contact with the gate electrode and source electrode of the chip 7 to form an electrical connection.

[0025] Furthermore, the gate lead 12, source lead 13, gate conductive post 10, source conductive post 11, gate slot and source slot on the frame 3 are all made of oxygen-free copper to ensure the conductivity of the components; the main structure of the frame 3 and the cover plate 4 is made of epoxy resin material to provide insulation and mechanical stability for the mounting structure.

[0026] Preferably, the mounting structure is a serialized size design, including a variety of external size specifications. The frame 3 is a general structure that can be adapted to a variety of aerospace-grade radiation-resistant power MOSFET bare cores smaller than its internal cavity size. The cover plate 4 is a customizable structure that can be matched with the electrode layout of different chips 7 by modifying the layout of the gate pin 8 and the source pin 9.

[0027] Preferably, the mounting structure can be extended to adapt to bipolar transistors, diodes and multipolar power semiconductor chips. When extended to diode-type bipolar chips, it can be achieved by leading out the front electrode of the chip through the source pin 9 and cutting the gate portion of the mounting plate 4. When extended to multipolar chips, the frame 3 can be customized and modified while keeping the pressing method and electrical connection method unchanged.

[0028] Example 2 The method of using this invention is as follows: S1 Frame Fixing: The frame 3 of the mounting structure is passed through the PCB board 1 through the gate lead-out terminals (gate lead-out terminal 14, gate lead-out terminal 2 16, and source lead-out terminals (source lead-out terminal 15, source lead-out terminal 2 17), and the frame 3 is fixed and electrically connected to the PCB board 1 by soldering on the back of the PCB board 1, ensuring that the PCB board circuit 2 matches the frame lead-out terminals and the drain position on the back of the chip 7; S2 Chip Mounting: The aerospace-grade radiation-resistant power MOSFET bare core 7 is mounted on the PCB board 1 in the area corresponding to the chip drain using UV peelable conductive adhesive; S3 Snap-on plate: Align the snap-on plate 4 with the installation position of the frame 3, and detachably connect the snap-on plate 4 to the frame 3 by fixing screws (fixing screw 1 5, fixing screw 2 6, fixing screw 3 18, fixing screw 4 19). During the snap-on process, the snap-on plate gate lead-out terminal 12 and the snap-on plate source lead-out terminal 13 are inserted into the gate slot and source slot of the frame 3 to form an electrical interconnection. S4 Press-fit connection: During the tightening of the fixing screws (fixing screw 1 5, fixing screw 2 6, fixing screw 3 18, fixing screw 4 19), the gate pin 8 and source pin 9 on the buckle plate 4 come into contact with and are compressed on the gate and source electrodes on the surface of the chip 7. The spring force of the pins makes them fit tightly with the chip electrodes, forming a stable electrical connection, completing the chip 7 mounting and circuit conduction. S5 Chip Replacement: When chip 7 needs to be replaced, unscrew the fixing screws (fixing screw 1 5, fixing screw 2 6, fixing screw 3 18, fixing screw 4 19) and remove the backing plate 4. Apply UV irradiation / heat treatment to chip 7 and the PCB board mounting area to remove the UV peelable conductive adhesive. Then remove the failed chip 7 and clean the residual adhesive. S6 Repeat installation: Mount the new power semiconductor chip on the corresponding area of ​​PCB board 1, and repeat steps S2-S4 to complete the rapid installation of the new chip and circuit conduction.

[0029] Example 3 This mounting structure can be adapted to different chip sizes by adjusting different frames and mounting plates. The mounting structure provided in this embodiment has an outer dimension of 12mm*10mm*5.6mm and an inner dimension of 10mm*7.9375mm, which is suitable for chips with a size of 8mm*6mm or less; This mounting structure is designed with three different sizes: 6mm*8mm, 12mm*10mm and 16mm*12mm, to match the external dimensions of different chip sizes; The frame 3 in this mounting structure is a general structure that can be used for chips smaller than the internal cavity size. The cover plate 4 is a custom structure. The gate pins 8 and source pins 9 can be modified to match the electrode layout of different chips. This mounting structure is suitable for triode chips such as MOS and bipolar transistors, as well as bipolar chips such as diodes. When expanding and modifying the backing plate 4, you only need to bring out the front electrode of the chip through the source pin 9 and cut off the gate part. When this mounting structure is extended to multi-polar chips (more than 3 poles), the general structural framework 3 can be customized and modified. As long as the crimping method and the electrical connection method are the same, they are all within the protection scope of this invention.

[0030] In summary, the beneficial effects of the present invention are as follows: 1. By adopting a vertical interconnect structure without sintering wire bonding, the electrical connection between the chip electrode and the PCB board is achieved by spring pin pressing, completely eliminating the metal wire bonding process, significantly reducing the parasitic inductance of the package, effectively improving the power conversion efficiency under high frequency and high power conditions, reducing electromagnetic interference, and meeting the design goals of low noise and low loss for aerospace power supplies. 2. Adopting a press-fit detachable structure design, combined with UV peelable conductive adhesive to fix the chip, it enables non-destructive and rapid disassembly and replacement of high-value radiation-resistant MOSFET bare chips, avoiding chip and substrate damage problems caused by traditional irreversible sintering bonding processes, significantly reducing the scrap rate in the testing and solution verification process, and improving the screening and testing efficiency of high-value devices; 3. It features modular and serialized size design and flexible structural adaptability. The frame is a general structure that can be adapted to chips of various specifications smaller than the internal cavity size. The cover plate can be matched with different chip electrode designs through customized pin layout. At the same time, it can be expanded to adapt to bipolar transistors, diodes and multipolar chips. It solves the problem that traditional structures need to customize exclusive substrates and bonding schemes for bare dies of different sizes. It has strong versatility and supports rapid iteration verification of multiple chip models. 4. It solves the problem that the entire power supply needs to be replaced when a single component fails in a traditional SIP packaged power supply, and realizes partial maintainability of the power device module. When a component fails, only the cover plate needs to be removed and the failed chip replaced to restore the module function, which greatly reduces the later maintenance cost of aerospace power supplies. 5. The structural materials and process design meet the requirements of aerospace-grade high reliability applications. The contact end of the ejector pin is made of pure gold to prevent chip scratches, the conductive parts are made of oxygen-free copper to ensure conductivity, the lead-out end is tin-plated to prevent oxidation, and the main frame and buckle plate are made of epoxy resin to provide excellent insulation and mechanical structural stability. The whole has good aerospace-grade environmental adaptability.

[0031] Those skilled in the art will understand that the above embodiments can be modified in form and detail in practical applications without departing from the spirit and scope of the invention.

Claims

1. A crimp-type mounting structure, characterized in that: The device includes a frame (3) mounted on a PCB board (1) and a snap-on plate (4) detachably connected to the frame (3). A chip (7) is mounted on the drain circuit area of ​​the PCB board (1). The frame (3) is provided with a gate slot, a source slot, and multiple gate leads (14), gate leads (16), source leads (15), and source leads (17) for electrical contact with the PCB board circuit (2) of the PCB board (1). The snap-on plate (4) integrates a snap-on gate lead (12) electrically connected to the gate slot and an end electrically connected to the source slot. The buckle source terminal (13); the buckle gate terminal (12) is connected to a plurality of gate pins (8) through gate conductive posts (10), and the buckle source terminal (13) is connected to a plurality of source pins (9) through source conductive posts (11). The lower ends of the gate pins (8) and the source pins (9) form elastic pressure contacts with the gate electrode and the source electrode of the chip (7), respectively. When the buckle (4) is fastened to the frame (3), the buckle gate terminal (12) and the buckle source terminal (13) are inserted into the gate slot and the source slot of the frame (3) to form electrical contacts.

2. The crimp-type mounting structure as described in claim 1, characterized in that: The buckle plate (4) is connected to the frame (3) by fixing screw one (5), fixing screw two (6), fixing screw three (18), and fixing screw four (19).

3. The crimp-type mounting structure as described in claim 1, characterized in that: The frame (3) and the buckle (4) are both made of epoxy resin insulating material. The buckle gate lead-out end (12), the buckle source lead-out end (13), the gate conductive pillar (10), the source conductive pillar (11), the gate slot, and the source slot are all made of oxygen-free copper material.

4. The crimp-type mounting structure as described in claim 1, characterized in that: Both the gate pin (8) and the source pin (9) are elastic pins with a two-stage spring pin structure.

5. The crimp-type mounting structure as described in claim 1, characterized in that: The PCB board circuit (2) is used to carry the chip (7) and realize electrical connection.

6. The crimp-type mounting structure as described in claim 1, characterized in that: The frame (3) is also provided with multiple threaded holes.

7. The crimp-type mounting structure as described in claim 1, characterized in that: The drain of the chip (7) is attached to the corresponding drain line area of ​​the PCB board (1) by conductive adhesive to form an electrical path.

8. The crimp-type mounting structure as described in claim 1, characterized in that: The ends of the gate pin (8) and source pin (9) that contact the chip (7) are made of pure gold.

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