WO2022088173A1 - A power device with a spring clip - Google Patents

A power device with a spring clip Download PDF

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Publication number
WO2022088173A1
WO2022088173A1 PCT/CN2020/125820 CN2020125820W WO2022088173A1 WO 2022088173 A1 WO2022088173 A1 WO 2022088173A1 CN 2020125820 W CN2020125820 W CN 2020125820W WO 2022088173 A1 WO2022088173 A1 WO 2022088173A1
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WO
WIPO (PCT)
Prior art keywords
spring clip
module
power
power device
power module
Prior art date
Application number
PCT/CN2020/125820
Other languages
French (fr)
Inventor
Jan Abraham Ferreira
Wenbo Wang
Guoqi Zhang
Original Assignee
Shenzhen Institute Of Wide-bandgap Semiconductors
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Shenzhen Institute Of Wide-bandgap Semiconductors filed Critical Shenzhen Institute Of Wide-bandgap Semiconductors
Priority to PCT/CN2020/125820 priority Critical patent/WO2022088173A1/en
Publication of WO2022088173A1 publication Critical patent/WO2022088173A1/en

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0213—Electrical arrangements not otherwise provided for
    • H05K1/0237—High frequency adaptations
    • H05K1/0243—Printed circuits associated with mounted high frequency components
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/18—Printed circuits structurally associated with non-printed electric components
    • H05K1/181—Printed circuits structurally associated with non-printed electric components associated with surface mounted components
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/325—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by abutting or pinching, i.e. without alloying process; mechanical auxiliary parts therefor
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K3/00—Apparatus or processes for manufacturing printed circuits
    • H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
    • H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
    • H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
    • H05K3/341—Surface mounted components
    • H05K3/3431—Leadless components
    • H05K3/3436—Leadless components having an array of bottom contacts, e.g. pad grid array or ball grid array components
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/10—Details of components or other objects attached to or integrated in a printed circuit board
    • H05K2201/10431—Details of mounted components
    • H05K2201/10598—Means for fastening a component, a casing or a heat sink whereby a pressure is exerted on the component towards the PCB

Definitions

  • the present invention relates to the field of semiconductors, and more specifically to power devices with meshed spring clips.
  • Wide bandgap semiconductor materials represented by gallium nitride and silicon carbide have the characteristics of high electron saturation speed, high thermal conductivity, high electron density, and high breakdown strength, and are suitable for making of high-voltage, high-frequency and high-power power devices. Due to the high switching frequency of transistors with wide bandgap semiconductor materials, the parasitic inductance between transistors using wide bandgap semiconductor materials play more significant role.
  • a method of adding more copper area in the PCB design to optimize circuit parasitic parameters is usually adopted, and a heat dissipation module is additionally configured.
  • the PCB of this technical solution has a relatively high cost and a large area.
  • the present invention discloses
  • a power device with a spring clip characterized by and comprising: a circuit substrate, a power module, and a meshed spring clip which connects the circuit substrate and the power module;
  • the circuit substrate includes at least two through holes, the first extension portion of the meshed spring clip passes through the through hole pressing against the first surface of the said circuit substrate, and the second extension portion of the meshed spring clip passes around the power module and presses against the second surface of the power module;
  • the second surface of the substrate and the first surface of the power module are connected by soldering or pressure contacts at least on one point.
  • the meshed spring clip comprises at least two rectangular frames interconnected in a mesh shape, and at least two pairs of extensions arranged symmetrically outside the mesh interconnect rectangular frame.
  • the power module comprises: a metal contact area, a capacitor layer, a transistor module, a lead frame; whereas the capacitor layer and the transistor module are sandwiched between the metal contact area and between the lead frames.
  • the metal contact area is located on the first surface of the power module, the substrate is connected to the metal contact area; and the lead frame is located on the second side of the power module; the lead frame is in contact with the rectangular frame of the meshed spring clip.
  • the semiconductor devices are electrically connected to the lead frame.
  • the power module further comprises the filling support area which is between the metal connection area, the transistor module, and the lead frame, or between the metal connection area, the capacitor module, and the transistor module.
  • the transistor module is a sandwiched GaN module.
  • the surface of the meshed spring clip comprises a copper layer or a tin layer; and the material of the metal contact area is copper.
  • the substrate is a PCB.
  • the capacitor is thin foil for plastic-like material.
  • Fig. 1 is a side view of a power device with a meshed spring clip provided in the first embodiment.
  • Fig. 2 is a side view of the power module provided in the first embodiment.
  • Fig. 3 is a top view of a power device with a meshed spring clip provided in the first embodiment.
  • This embodiment provides a power device with a meshed spring clip, as shown in Figs. 1-3.
  • the power device includes a meshed spring clip 1, a Sandwiched GaN module 2, and a Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4.
  • PCB Printed Circuit Board
  • the Sandwiched GaN module 2 includes a lead frame 8, a GaN power transistor die 9, a filler laminate 10, a capacitive laminate 11, and copper connections 12.
  • the copper connections 12 includes a plurality of regions.
  • the lead frame 8 is located at the bottom of the Sandwiched GaN module 2 and is in contact with the meshed spring clip 1;
  • the copper connections 12 is located on the top of the Sandwiched GaN module 2 and is in contact with the Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4;
  • the capacitive laminate is attached to different connection assemblies 12, or sandwiched between the copper connections 12 and the filler laminate 10;
  • the GaN power transistor die 9 is attached to the lead frame 8, and the upper surface of the GaN power transistor die 9 is in contact with the copper connections 12;
  • the filler laminate 10 is arranged in the GaN power transistor die 9 and fills multiple regions of the support assembly 10.
  • the connecting assembly 12 is preferably made from copper.
  • the lead frame 8 is in direct contact with the air, which improves the heat dissipation efficiency of the power device.
  • the lead frame material is a metal material, preferably copper.
  • the meshed spring clip 1 includes a net-like structure and multiple pairs of spring holding parts located outside the net-like structure.
  • the meshed spring clip 1 with a mesh structure can effectively shield the electromagnetic interference while exposing the lead frame 8 to the air as much as possible to maintain heat dissipation.
  • the upper and lower sides of the net-like structure are provided with two pairs of spring holding parts, and the left and right sides of the net-like structure are provided with a pair of spring holding parts.
  • the first end of the spring holding part is crimped on spring clip pressure point on PCB through the hole in PCB for spring clip 6 provided on the Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4.
  • PCB Printed Circuit Board
  • the second end of the spring holding part passes around the side surface of the Sandwiched GaN module 2, is curved to meet the lower surface of the Sandwiched GaN module 2, and is clamped on the spring clip pressure point on module 3 situated on the lead frame 8 on the lower surface of the Sandwiched GaN module 2.
  • the mechanical performance characteristics of the spring holding part enables the mechanical pressure applied by the Sandwiched GaN module 2 to have a certain degree of elasticity, so as to avoid mechanical damage to the Sandwiched GaN module 2 caused by rigid pressure.
  • the lower surface of the Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4 is also provided with a plurality of protrusions which are connected to the upper surface of the Sandwiched GaN module 2.
  • the connecting assembly 12 is connected at the shaped pressure contact or solder joint 7; the interconnection may be a welded interconnection or a crimped interconnection.
  • the lead frame includes a zero-voltage ring on leadframe 13 and a dynamic voltage pad on leadframe 14.
  • the surface of the meshed spring clip 1 is coated with a highly conductive layer material, preferably copper or tin.
  • the power devices are power devices such as IGBTs and MOSFETs, and the GaN transistors may also be other transistors using wide-bandgap semiconductor materials, such as SiC.
  • a mesh structure is provided on the meshed spring clip to generate a shielding electric field, which effectively solves the problem of electromagnetic interference; by adopting a capacitive layer, the effect of commutation loop of the transistor module is reduced; and the lead frame is exposed to the air instead of the existing
  • the power module and the substrate are connected through the meshed spring clip and the corresponding filling support area is set, and the meshed spring clip is interconnected under better elastic mechanical pressure and power modules.

Abstract

The invention discloses a power circuit assembly with a spring clip, which includes: a circuit substrate, a power module and a meshed spring clip connecting the circuit substrate and the power module; the circuit substrate includes at least two through holes, and the first extension part of the clip presses against the first surface of the circuit substrate passing through the through hole, and the second extension part of the meshed spring clip passes through the first end of the power module and presses against the second surface on the power module. The invention provides a low cost solution for assembling multiple transistor power modules to printed circuit boards and solves the technical problem associated with thermo-mechanical stresses occurring in large area electrical interfaces while at the same time providing the means for effectively dissipating heat and effectively tune the values of the electrical parasitic parameters.

Description

A power device with a spring clip Technical Field
The present invention relates to the field of semiconductors, and more specifically to power devices with meshed spring clips.
Background Art
Wide bandgap semiconductor materials represented by gallium nitride and silicon carbide have the characteristics of high electron saturation speed, high thermal conductivity, high electron density, and high breakdown strength, and are suitable for making of high-voltage, high-frequency and high-power power devices. Due to the high switching frequency of transistors with wide bandgap semiconductor materials, the parasitic inductance between transistors using wide bandgap semiconductor materials play more significant role. In the prior art, in order to overcome the technical problems of high parasitic inductance and restricted heat dissipation, a method of adding more copper area in the PCB design to optimize circuit parasitic parameters is usually adopted, and a heat dissipation module is additionally configured. The PCB of this technical solution has a relatively high cost and a large area.
Disclosure of Invention
In order to overcome the shortcomings of the prior art and solve the high cost and technical problems, including large area of a power chip with low parasitic parameters and high heat dissipation, the present invention discloses
a power device with a spring clip, characterized by and comprising: a circuit  substrate, a power module, and a meshed spring clip which connects the circuit substrate and the power module; the circuit substrate includes at least two through holes, the first extension portion of the meshed spring clip passes through the through hole pressing against the first surface of the said circuit substrate, and the second extension portion of the meshed spring clip passes around the power module and presses against the second surface of the power module;
the second surface of the substrate and the first surface of the power module are connected by soldering or pressure contacts at least on one point.
Preferable, wherein the meshed spring clip comprises at least two rectangular frames interconnected in a mesh shape, and at least two pairs of extensions arranged symmetrically outside the mesh interconnect rectangular frame.
Preferable, wherein the power module comprises: a metal contact area, a capacitor layer, a transistor module, a lead frame; whereas the capacitor layer and the transistor module are sandwiched between the metal contact area and between the lead frames.
Preferable, wherein the metal contact area is located on the first surface of the power module, the substrate is connected to the metal contact area; and the lead frame is located on the second side of the power module; the lead frame is in contact with the rectangular frame of the meshed spring clip.
Preferable, wherein the semiconductor devices are electrically connected to the lead frame.
Preferable, wherein the power module further comprises the filling support area which is between the metal connection area, the transistor module, and the lead frame, or between the metal connection area, the capacitor module, and the transistor module.
Preferable, wherein the transistor module is a sandwiched GaN module.
Preferable, wherein the surface of the meshed spring clip comprises a copper layer or a tin layer; and the material of the metal contact area is copper.
Preferable, wherein the substrate is a PCB.
Preferable, wherein the capacitor is thin foil for plastic-like material.
Brief Description of Drawings
Fig. 1 is a side view of a power device with a meshed spring clip provided in the first embodiment.
Fig. 2 is a side view of the power module provided in the first embodiment.
Fig. 3 is a top view of a power device with a meshed spring clip provided in the first embodiment.
Mode (s) for Carrying Out the Invention
The specific implementation of the present invention will be described in detail below. It is necessary to point out that the following implementations are only used for further description of the present invention, and cannot be understood as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made still belong to the protection scope of the present invention.
This embodiment provides a power device with a meshed spring clip, as shown in Figs. 1-3. The power device includes a meshed spring clip 1, a Sandwiched GaN module 2, and a Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4.
The Sandwiched GaN module 2 includes a lead frame 8, a GaN power transistor die 9, a filler laminate 10, a capacitive laminate 11, and copper connections 12. The copper connections 12 includes a plurality of regions. The lead frame 8 is located at  the bottom of the Sandwiched GaN module 2 and is in contact with the meshed spring clip 1; the copper connections 12 is located on the top of the Sandwiched GaN module 2 and is in contact with the Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4; the capacitive laminate is attached to different connection assemblies 12, or sandwiched between the copper connections 12 and the filler laminate 10; the GaN power transistor die 9 is attached to the lead frame 8, and the upper surface of the GaN power transistor die 9 is in contact with the copper connections 12; the filler laminate 10 is arranged in the GaN power transistor die 9 and fills multiple regions of the support assembly 10. In the space formed by one or more of the capacitors 11, the pressure applied by the meshed spring clip will be buffered on the full assembly 2. The connecting assembly 12 is preferably made from copper. The lead frame 8 is in direct contact with the air, which improves the heat dissipation efficiency of the power device. The lead frame material is a metal material, preferably copper.
The meshed spring clip 1 includes a net-like structure and multiple pairs of spring holding parts located outside the net-like structure. The meshed spring clip 1 with a mesh structure can effectively shield the electromagnetic interference while exposing the lead frame 8 to the air as much as possible to maintain heat dissipation. As shown in Figure 3, the upper and lower sides of the net-like structure are provided with two pairs of spring holding parts, and the left and right sides of the net-like structure are provided with a pair of spring holding parts. The first end of the spring holding part is crimped on spring clip pressure point on PCB through the hole in PCB for spring clip 6 provided on the Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4. The second end of the spring holding part passes around the side surface of the Sandwiched GaN module 2, is curved to meet the lower surface of the Sandwiched GaN module 2, and is clamped on the spring clip pressure point on  module 3 situated on the lead frame 8 on the lower surface of the Sandwiched GaN module 2. The mechanical performance characteristics of the spring holding part enables the mechanical pressure applied by the Sandwiched GaN module 2 to have a certain degree of elasticity, so as to avoid mechanical damage to the Sandwiched GaN module 2 caused by rigid pressure. In addition to the connection between the Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4 and the Sandwiched GaN module 2 by the meshed spring clip 1, the lower surface of the Printed Circuit Board (PCB) that contains the rest of the electronic circuitry 4 is also provided with a plurality of protrusions which are connected to the upper surface of the Sandwiched GaN module 2. The connecting assembly 12 is connected at the shaped pressure contact or solder joint 7; the interconnection may be a welded interconnection or a crimped interconnection. The lead frame includes a zero-voltage ring on leadframe 13 and a dynamic voltage pad on leadframe 14.
In order to further improve the electric field shielding, the surface of the meshed spring clip 1 is coated with a highly conductive layer material, preferably copper or tin.
The power devices are power devices such as IGBTs and MOSFETs, and the GaN transistors may also be other transistors using wide-bandgap semiconductor materials, such as SiC.
In this embodiment, a mesh structure is provided on the meshed spring clip to generate a shielding electric field, which effectively solves the problem of electromagnetic interference; by adopting a capacitive layer, the effect of commutation loop of the transistor module is reduced; and the lead frame is exposed to the air instead of the existing The power module and the substrate are connected through the meshed spring clip and the corresponding filling support area is set, and the meshed spring clip is interconnected under better elastic mechanical pressure and  power modules. In summary, this embodiment realizes low parasitic parameters and high heat dissipation of a wide band gap semiconductor power device with low cost and small area.
Although the exemplary embodiments of the present invention have been described for illustrative purposes, those skilled in the art will understand that they can be modified in form and details without departing from the scope and spirit of the invention disclosed in the appended claims. Various modifications, additions and substitutions are made, and all these changes shall fall within the protection scope of the appended claims of the present invention, and the various steps in the various departments and methods of the products claimed by the present invention can be combined in any combination. Therefore, the description of the embodiments disclosed in the present invention is not intended to limit the scope of the present invention, but to describe the present invention. Accordingly, the scope of the present invention is not limited by the above embodiments, but is defined by the claims or their equivalents.

Claims (10)

  1. A power device with a spring clip, characterized by and comprising: a circuit substrate, a power module, and a meshed spring clip which connects the circuit substrate and the power module; the circuit substrate includes at least two through holes, the first extension portion of the meshed spring clip passes through the through hole pressing against the first surface of the said circuit substrate, and the second extension portion of the meshed spring clip passes around the power module and presses against the second surface of the power module;
    The second surface of the substrate and the first surface of the power module are connected by soldering or pressure contacts at least on one point.
  2. The power device with a spring clip according to claim 1, wherein the meshed spring clip comprises at least two rectangular frames interconnected in a mesh shape, and at least two pairs of extensions arranged symmetrically outside the mesh interconnect rectangular frame.
  3. The power device with a spring clip according to claim 1, where in the power module comprises: a metal contact area, a capacitive layer, a transistor module, a lead frame; whereas the capacitive layer and the transistor module are sandwiched between the metal contact area and between the lead frames.
  4. The power device with a spring clip according to claim 3, wherein the metal contact area is located on the first surface of the power module, the substrate is connected to the metal contact area; and the lead frame is located on the second side of the power module; the lead frame is in contact with the rectangular frame of the meshed spring clip.
  5. The power device with a spring clip according to claim 3, wherein the  semiconductor devices are electrically connected to the lead frame.
  6. The power device with a spring clip according to claim 3, where in the power module further comprises the filling support area which is among the metal connection area, the transistor module, and the lead frame, or among the metal connection area, the capacitor module, and the transistor module.
  7. The power device with a spring clip according to any one of claims 1-6, wherein the transistor module is a sandwiched GaN module.
  8. The power device with a spring clip according to any one of claims 1-6, wherein the surface of the meshed spring clip comprises a copper layer or a tin layer; and the material of the metal contact area is copper.
  9. The power device with a spring clip according to any one of claims 1-6, wherein the substrate is a PCB.
  10. The power device with a spring clip according to any one of claims 3-6, wherein the capacitor is thin foil for plastic-like material.
PCT/CN2020/125820 2020-11-02 2020-11-02 A power device with a spring clip WO2022088173A1 (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090135566A1 (en) * 2007-11-26 2009-05-28 Samsung Electronics Co., Ltd. Printed circuit board assembly and liquid crystal display having the same
US20120250294A1 (en) * 2011-03-29 2012-10-04 Shenzhen China Star Optoelectronics Technology Co, Ltd. Backlight Module And Liquid Crystal Display Employing Same
CN203751990U (en) * 2014-03-31 2014-08-06 昌河飞机工业（集团）有限责任公司 Elastic clamp
US20180122782A1 (en) * 2015-05-06 2018-05-03 Siemens Aktiengesellschaft Power Module

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090135566A1 (en) * 2007-11-26 2009-05-28 Samsung Electronics Co., Ltd. Printed circuit board assembly and liquid crystal display having the same
US20120250294A1 (en) * 2011-03-29 2012-10-04 Shenzhen China Star Optoelectronics Technology Co, Ltd. Backlight Module And Liquid Crystal Display Employing Same
CN203751990U (en) * 2014-03-31 2014-08-06 昌河飞机工业（集团）有限责任公司 Elastic clamp
US20180122782A1 (en) * 2015-05-06 2018-05-03 Siemens Aktiengesellschaft Power Module

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