An embedded power module test fixture and method of making the same

Abstract

The application discloses an embedded power module test fixture and a manufacturing method thereof, relates to the technical field of semiconductor power module testing, and aims to solve the problem of large parasitic parameters of a test fixture and limited testing precision in the prior art. The test fixture comprises a probe card, spring needles, connecting lines and a crimping box. The probe card is a PCB circuit board on which a test circuit diagram is printed, and a needle sleeve, a threaded hole and a cable interface are reserved on the probe card. The spring needles are installed in place through the needle sleeve. One end of the connecting line is connected with the cable interface of the probe card, and the other end of the connecting line is connected with a testing machine. A reinforcing structural member is fixed to the back of the probe card through connecting screws. The crimping box is used for accommodating and fixing the probe card, and makes the welding pads of a measured module contact the spring needles through a crimping action to form a test loop. The application replaces the traditional manual wire welding connection with a PCB printed circuit, greatly reduces the parasitic inductance and resistance of the test loop, and improves the signal reliability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor power module testing technology, and in particular to an embedded power module test fixture and its manufacturing method, which provides an embedded power module test fixture and its manufacturing method with low parasitic parameters, reliable connection, and easy quick replacement and maintenance. Background Technology

[0002] With the rapid development of new energy vehicles and other fields, the performance of power modules, as the core component of inverters, is crucial. Embedded power modules, as an advanced packaging form, directly embed power chips inside printed circuit boards (PCBs), offering advantages such as low thermal resistance, low parasitic inductance, and high packaging density.

[0003] In the production testing phase of embedded power modules, electrical parameter testing of the internal power chips is required. Currently, the industry commonly uses customized test fixtures, whose core electrical connection method involves soldering one end of a wire to the metal sleeve at the tail of a spring probe, and soldering or connecting the other end to a standard interface to achieve the electrical connection. While this method avoids directly soldering the wire to the module product, it still has a series of inherent drawbacks that cannot be overcome, becoming a bottleneck for improving testing quality and efficiency. 1. Introduction of secondary parasitic parameters limits test accuracy: Inside the fixture, additional parasitic inductance and resistance are introduced from the spring probe to the standard interface traces. For testing high-frequency, high-current wide-bandgap power modules, these intrinsic parasitic parameters of the fixture will severely distort the switching waveform, leading to inaccurate dynamic parameter measurements and failing to accurately reflect the module's performance.

[0004] 2. Complex manufacturing and low reliability: The extensive manual welding work inside requires highly skilled workers and is prone to defects such as incomplete welds and cold welds. Each weld point is a potential failure point and may fail during use due to vibration, thermal stress, etc., resulting in unstable test signals and poor fixture reliability.

[0005] 3. Poor maintainability: When a single probe or wire is damaged, repair is difficult and often requires complete rework or scrapping, resulting in high maintenance costs.

[0006] 4. Electrical performance bottleneck: The solder joints themselves have a significant contact resistance, which affects the accuracy of the test.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide an embedded power module test fixture and its manufacturing method, which can improve the testing accuracy of embedded power modules.

[0009] To achieve the above objectives / to solve the above technical problems, the present invention adopts the following technical solution: The test fixture includes: A probe card is a PCB circuit board with a test circuit diagram printed on it. The probe card has multiple pin sleeves, cable interfaces and threaded holes. Spring needle, the spring needle is securely connected to the needle sleeve; The connecting cable has one end electrically connected to the cable interface and the other end connected to an external testing machine. The reinforcing structural component is fixedly connected to the threaded hole on the probe card by connecting screws; Crimp box, used to install probe cards.

[0010] The probe card is a custom-designed printed circuit board based on the layout of the module under test and the testing requirements. Pre-defined electrical connection lines are etched onto the board. The pin sleeve 11 on the probe card 1 is used to mount the spring pins 5. Spring pins 5 with matching spring force, current, material, and impedance are selected. Appropriate pin sleeves 11 are selected according to the spring pin 5 model for soldering, and the spring pins 5 are installed in the pin sleeves 11. This avoids the need for soldering for fixation, reduces parasitic parameters, and improves reliability. Reinforcing structural components support the probe card and prevent deformation. The connecting cables use standard interfaces, allowing for quick connection to the cable interfaces on the probe card, facilitating rapid replacement and verification of the fixture. The crimp box houses and secures the assembled probe card, and through a crimping action, ensures tight contact between the pads of the embedded power module under test and the spring pins, forming a test circuit.

[0011] Furthermore, the reinforcing structural components include a support plate and a structural plate, with the support plate located between the probe card and the structural plate.

[0012] The support plate and the structural plate form a frame structure, which is fixed to the bottom of the probe card by connecting screws, thereby providing mechanical support for the probe card, distributing pressure, and preventing the printed circuit board from bending and deforming during repeated pressing tests.

[0013] Furthermore, the support plate is made of aluminum, and the structural plate is made of epoxy glass fiber composite material.

[0014] Furthermore, the probe card is also equipped with positioning pins.

[0015] Positioning pins provide guidance for the module under test, thus facilitating its positioning.

[0016] Furthermore, the crimping box includes a pressing handle and a pressing bar; During testing: The pressure bar comes into contact with the product being tested.

[0017] The crimp box is used to support and fix the assembled probe card and reinforcing structure, and provides controllable pressure to press the embedded power module under test against the probe card, so that the test pads on the module surface and the corresponding spring pin tips form a stable and reliable electrical contact, thereby forming a test circuit.

[0018] Furthermore, the circuit design of the probe card includes internal serial lines.

[0019] The probe card's circuit design includes internal series wiring to simulate or replace gate resistors during testing when the embedded power module lacks internal gate resistors, ensuring the normal series measurement loop of the parallel chip gates. For example, for some silicon carbide (SiC) power modules that do not have internal gate resistors, the required gate series resistors or connecting lines can be directly integrated into the probe card's circuit design, thus completing the necessary electrical configuration at the fixture level, ensuring test accuracy, and avoiding the unreliability of external flying wire connections. Figure 6 As shown, the test probe is set at the white dot. The gate can be connected in series with wiring at the yellow box and then led out to the communication interface, or four gate resistors can be installed here and then led out to the communication interface.

[0020] Furthermore, one side of the crimp box has an opening for leading out the connecting wire.

[0021] The opening is used to provide a passageway for the connecting wire.

[0022] Furthermore, the method for manufacturing the test fixture includes the following steps: Step 1: Based on the circuit board layout and electrical testing requirements of the product under test, design and manufacture a probe card with test circuitry, and reserve pin sleeves and cable interfaces on the probe card. Step 2: Fabricate a support plate and a structural plate according to the dimensions of the probe card, and assemble and fix the probe card, support plate, and structural plate using connecting screws; Step 3: Secure the sleeve in the probe card's pin sleeve mounting position and install the spring pin; solder the standard connector to the cable interface. Step 4: Based on the structure of the assembled probe card, customize the crimp box to ensure that the crimp box can fix the probe card and provide a stable crimping stroke; Step 5: Place the assembled probe card into the crimp box for fixation, and connect the probe card to the testing machine via the connecting wire to complete the preparation of the test fixture.

[0023] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: 1. The use of etched copper foil traces on printed circuit boards to replace traditional manual soldering traces results in neat paths and controllable lengths, greatly reducing parasitic inductance and resistance in the test circuit and improving the accuracy of high-frequency and dynamic testing.

[0024] 2. High connection reliability and stability: It eliminates dozens to hundreds of manual solder joints, and the main connections are achieved through PCB soldering and mechanical fastening, resulting in better consistency, stronger resistance to vibration and thermal fatigue, and more stable and reliable test results.

[0025] 3. The modular probe cards facilitate easy maintenance and quick replacement. When testing different products, simply replace the probe card designed for that product. The reinforcing structural components and crimp boxes are reusable, enabling rapid fixture conversion and improving the flexibility of the testing line. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the probe card structure of the present invention; Figure 3 This is a top view of the probe card of the present invention; Figure 4 This is a schematic diagram of the crimping box of the present invention; Figure 5 This is a schematic diagram of the spring pin arrangement of the present invention; Figure 6 This is a schematic diagram of the probe card circuit of the present invention.

[0028] In the diagram: 1. Probe card; 11. Needle sleeve; 12. Cable interface; 13. Positioning pin; 2. Support plate; 3. Structural plate; 4. Connecting screw; 5. Spring pin; 6. Crimping box; 61. Press handle; 62. Pressure bar; 63. Opening; 7. Connecting wire. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present application or its application or use. Example 1

[0030] like Figure 1 , Figure 3As shown, this embodiment provides an embedded power module test fixture, which includes: Probe card 1 is a PCB circuit board with a test circuit diagram printed on it. Probe card 1 has multiple pin sleeves 11, cable interfaces 12 and threaded holes. Spring needle 5, which is securely connected to needle sleeve 11; Connecting cable 7, one end of which is electrically connected to cable interface 12, and the other end is connected to an external testing machine; The reinforcing structural component is fixedly connected to the threaded hole on the probe card 1 by the connecting screw 4. Crimp box 6 is used to install probe card 1.

[0031] The probe card 1 is a custom-designed printed circuit board based on the layout of the module under test and the testing requirements. Pre-defined electrical connection lines are etched onto the board. The pin sleeve 11 on the probe card 1 is used to mount the spring pins 5. Spring pins 5 with matching spring force, current, material, and impedance are selected. Appropriate pin sleeves 11 are selected according to the spring pin 5 model for soldering, and the spring pins 5 are installed in the pin sleeves 11. This avoids the need for soldering for fixation, reduces parasitic parameters, and improves reliability. Reinforcing structural components support the probe card 1 and prevent deformation. The connecting cable 7 uses a standard interface, allowing for quick connection to the cable interface 12 on the probe card 1, facilitating rapid replacement and verification of the fixture. The crimp box 6 houses and secures the assembled probe card 1, and through a crimping action, ensures tight contact between the pads of the embedded power module under test and the spring pins 5, forming a test circuit.

[0032] like Figure 2 As shown, the reinforcing structure includes a support plate 2 and a structural plate 3, with the support plate 2 located between the probe card 1 and the structural plate 3.

[0033] The support plate 2 and the structural plate 3 form a frame structure, which is fixed to the bottom of the probe card 1 by connecting screws 4, thereby providing mechanical support for the probe card 1, dispersing pressure, and preventing the printed circuit board from bending and deforming during repeated pressing tests.

[0034] Support plate 2 is made of aluminum, and structural plate 3 is made of epoxy glass fiber composite material.

[0035] like Figure 3 As shown, the probe card 1 is also equipped with a positioning pin 13.

[0036] The positioning pin 13 can provide guidance for the module under test, thereby facilitating the positioning of the module under test.

[0037] like Figure 1 As shown, the crimping box 6 includes a pressing handle 61 and a pressing rod 62; During testing: the pressure bar 62 comes into contact with the product being tested.

[0038] The crimp box 6 is used to support and fix the assembled probe card 1 and the reinforcing structure, and provides controllable pressure to press the embedded power module under test against the probe card 1, so that the test pad on the surface of the module and the tip of the corresponding spring pin 5 form a stable and reliable electrical contact, thereby forming a test circuit.

[0039] like Figure 6 As shown, the circuit design of probe card 1 includes internal series wiring.

[0040] The circuit design of probe card 1 includes internal series wiring to simulate or replace the gate resistor connection during testing when the embedded power module does not have a gate resistor mounted, ensuring the normal series measurement loop of the parallel chip gate. For example, for some silicon carbide (SiC) power modules that do not have gate resistors mounted internally, the required gate series resistor or connection wiring can be directly integrated into the circuit design of probe card 1, thereby completing the necessary electrical configuration at the fixture level, ensuring test accuracy, and avoiding the unreliability of external flying wire connections. Figure 6 As shown, the test probe is set at the white dot. The gate can be connected in series with wiring at the yellow box and then led out to the communication interface, or four gate resistors can be installed here and then led out to the communication interface.

[0041] like Figure 4 As shown, the crimp box 6 has an opening 63 on one side, which is used to lead out the connecting wire 7.

[0042] Opening 63 is used to provide a passage area for connecting line 7. Example 2

[0043] The method for manufacturing the test fixture includes the following steps: Step 1: Based on the circuit board layout design and electrical testing requirements of the product under test, design and manufacture a probe card 1 with test circuitry, and reserve a pin sleeve 11 and a cable interface 12 on the probe card 1. Step 2: Fabricate support plate 2 and structural plate 3 according to the dimensions of probe card 1, and assemble and fix probe card 1, support plate 2 and structural plate 3 with connecting screws 4; Step 3: Fix the sleeve 11 in the pin sleeve mounting position of the probe card 1 and install the spring pin 5, and solder the standard interface at the cable interface 12; Step 4: Based on the structure of the assembled probe card 1, customize the crimp box 6 to ensure that the crimp box 6 can fix the probe card 1 and provide a stable crimping stroke; Step 5: Place the assembled probe card 1 into the crimp box 6 for fixation, and connect the probe card 1 to the testing machine through the connecting wire 7 to complete the preparation of the test fixture.

[0044] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific posture. If the specific posture changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing this application and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this application.

[0045] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0047] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. An embedded power module test fixture, characterized in that, include: The probe card (1) is a PCB circuit board with a test circuit diagram printed on it. The probe card (1) is provided with multiple pin sleeves (11), cable interfaces (12) and threaded holes. Spring needle (5), which is fastened to the needle sleeve (11); Connecting line (7), one end of which is electrically connected to cable interface (12), and the other end is connected to test machine; A reinforcing structural component is fixedly connected to the threaded hole on the probe card (1) by a connecting screw (4); A crimp box (6) is used to install a probe card (1).

2. The embedded power module test fixture according to claim 1, characterized in that: The reinforcing structure includes a support plate (2) and a structural plate (3), with the support plate (2) located between the probe card (1) and the structural plate (3).

3. The embedded power module test fixture according to claim 2, characterized in that: The support plate (2) is made of aluminum, and the structural plate (3) is made of epoxy glass fiber composite material.

4. An embedded power module test fixture according to claim 1, characterized in that: The probe card (1) is also provided with a positioning pin (13).

5. An embedded power module test fixture according to claim 1, characterized in that: The crimping box (6) includes a pressing handle (61) and a pressing rod (62); During testing: the pressure bar (62) comes into contact with the product being tested.

6. An embedded power module test fixture according to claim 1, characterized in that: The circuit design of the probe card (1) includes internal serial lines.

7. An embedded power module test fixture according to claim 1, characterized in that: The crimp box (6) has an opening (63) on one side, which is used to lead out the connecting wire (7).

8. The method for manufacturing an embedded power module test fixture according to claim 1, characterized in that, The manufacturing method includes the following steps: Step 1: Based on the circuit board layout design and electrical testing requirements of the product under test, design and manufacture a probe card (1) with test circuitry, and reserve a pin sleeve (11) and a cable interface (12) on the probe card (1). Step 2: Make a support plate (2) and a structural plate (3) according to the size of the probe card (1), and assemble and fix the probe card (1), support plate (2) and structural plate (3) with connecting screws (4); Step 3: Fix the sleeve (11) in the pin sleeve mounting position of the probe card (1) and install the spring pin (5), and weld the standard interface at the cable interface (12); Step 4: Based on the structure of the assembled probe card (1), customize the crimp box (6) to ensure that the crimp box (6) can fix the probe card (1) and provide a stable crimping stroke; Step 5: Place the assembled probe card (1) into the crimp box (6) for fixation, and connect the probe card (1) to the testing machine through the connecting wire (7) to complete the preparation of the test fixture.

Images