Test tool for mos tube processing and test method thereof

Abstract

The invention discloses a test tool for mos tube processing and a test method thereof, and relates to the technical field of test tools. The test tool for mos tube processing comprises a tool base, a clamping driving mechanism, at least two oppositely arranged clamping units, a constant force control mechanism, a controller and a replaceable clamping assembly. According to the testing tool for mos tube processing, through a feedback control system composed of a pressure sensor, an elastic piece, a controller and a clamping driving mechanism, clamping force acting on an MOS tube can be monitored and accurately controlled in real time, when the pressure sensor detects that a force value reaches a preset threshold value, the controller immediately instructs the driving mechanism to stop, and the clamping force is accurately controlled. Therefore, the clamping force is constant in a safe and appropriate range, the clamping assembly can be detached and replaced quickly, the device is convenient to adapt to various types of products, clamping is stable during testing, operation is simple, the speed is high, and the testing accuracy and the product safety are improved.

Description

Technical Field

[0001] This invention relates to the field of testing tooling technology, specifically to testing tooling and testing methods for MOSFET processing. Background Technology

[0002] In the semiconductor manufacturing field, after MOSFETs are packaged, they need to undergo visual inspection and testing of key electrical parameters. Traditional test fixtures usually use simple mechanical or pneumatic clamps for clamping and positioning.

[0003] Existing technologies suffer from the following problems: these fixtures are mostly driven directly by screws or cylinders, and the clamping force often depends on the operator's experience or a rough setting of the air source pressure. The clamping force is difficult to control. Moreover, to accommodate MOSFETs of different package sizes (such as TO-220, TO-247, D-PAK, etc.), traditional tooling requires replacing the entire clamping module or using a general-purpose fixture with a large number of shims. This is cumbersome and the positioning accuracy is difficult to guarantee. Direct rigid clamping or traditional control methods can easily cause mechanical stress damage to the MOSFET's plastic package or internal chip due to excessive clamping force, or cause the product to loosen due to insufficient clamping force. Test probes are prone to poor contact, affecting the accuracy and consistency of test results. For multi-variety, small-batch production modes, frequent fixture changes lead to low testing speed, and general-purpose fixtures have poor adaptability to irregularly shaped packages, making it difficult to achieve fast and accurate changeover and positioning. In view of the shortcomings of existing technologies, this invention provides a test fixture and test method for MOSFET processing to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a testing fixture and method for MOSFET processing. Through a feedback control system comprised of a pressure sensor, an elastic element, a controller, and a clamping drive mechanism, the clamping force acting on the MOSFET can be monitored and precisely controlled in real time. When the pressure sensor detects that the force value reaches a preset threshold, the controller immediately instructs the drive mechanism to stop, thereby keeping the clamping force constant within a safe and suitable range. Furthermore, the clamping components are detachable and quickly replaceable, facilitating compatibility with various product models. The clamping is stable during testing, the operation is simple and fast, and the accuracy of testing and product safety are improved.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a test fixture for MOSFET processing, comprising a fixture base, a clamping drive mechanism, at least two opposing clamping units, a constant force control mechanism, a controller, and replaceable clamping components. The clamping drive mechanism is mounted on the fixture base and drives the clamping units to move towards or away from each other to clamp and release the MOSFET. The constant force control mechanism is connected to at least one of the clamping units and provides buffering during clamping and real-time monitoring of the clamping force. The controller is electrically connected to the clamping drive mechanism and the constant force control mechanism and receives force signals to control the drive action. The clamping components are detachably mounted at the ends of the clamping units for direct adaptation and contact with different types of MOSFETs.

[0006] Preferably, the clamping drive mechanism includes a transverse slide, a drive motor, and a bidirectional screw disposed on the tooling base. The drive motor is connected to the bidirectional screw, and the bidirectional screw is threadedly connected to the transverse slide.

[0007] Preferably, each clamping unit includes a movable platform, a support frame, and a limiting frame connected in sequence. The movable platform is slidably connected to the transverse slide. The constant force control mechanism further includes a track disposed on the transverse slide. The movable platform slides along the track and compresses or releases the elastic element. The pressure sensor is disposed at the end of the elastic element or the end of the track.

[0008] Preferably, the clamping assembly is mounted on the limiting frame via a rotary positioning mechanism; The rotary positioning mechanism includes a rotating shaft fixed on the limiting frame and a rotating platform rotatably connected to the rotating shaft, and the clamping assembly is mounted on the rotating platform.

[0009] Preferably, the rotary positioning mechanism further includes an angle locking component; The angle locking assembly includes a rotating disk that rotates synchronously with the rotating shaft, a sleeve disposed on the support frame or the limiting frame, an adjusting screw threadedly connected to the sleeve, and a slider slidably disposed in the sleeve and rotatably connected to the end of the adjusting screw. The rotating disk has multiple angle positioning holes around its periphery. A locking rod is fixed on the slider. Rotating the adjusting screw can drive the slider to slide, so that the locking rod can be inserted into or removed from the angle positioning hole.

[0010] Preferably, the rotary table has a polyhedral structure, with different clamping components mounted on at least two of its sides.

[0011] Preferably, the clamping assembly includes a clamping body, which is detachably connected to the rotary table via a plug-in assembly; The plug-in assembly includes a slot disposed on the rotary table and a plug block disposed on the clamp body. The plug block is provided with an elastic snap-fit ​​element. When the plug block is inserted into the slot, the elastic snap-fit ​​element snaps and fixes itself to the slot or the rotary table.

[0012] Preferably, the elastic snap-fit ​​element is a fitting ball, the insert block has an internal cavity and a spring, the fitting ball protrudes from the surface of the insert block and can snap into the recess of the inner wall of the slot.

[0013] Preferably, the clamping surface of the clamping body is provided with a rubber block, and the rubber block has a slot that matches the shape of the MOS tube to be tested.

[0014] The present invention also discloses a method for testing MOSFETs using the aforementioned test fixture, comprising the following steps: Step S1, selecting and installing the corresponding clamping assembly to the end of the clamping unit according to the model of the MOSFET to be tested; Step S2: Place the MOS transistor under test between the two sets of oppositely arranged clamping components; Step S3: The clamping drive mechanism is activated by the controller to drive the two sets of clamping units to move towards each other, so that the clamping components contact and clamp the MOS transistor. In step S4, during the clamping process, the elastic element of the constant force control mechanism is compressed, and the pressure sensor detects the clamping force in real time and feeds it back to the controller. Step S5: When the force value detected by the pressure sensor reaches a preset threshold, the controller controls the clamping drive mechanism to stop, thereby achieving constant force clamping. Step S6: Use a vision inspection device set above the fixture to perform visual inspection on the appearance or pin position of the MOSFET under constant force clamping. Step S7: Use a measurement probe to perform physical measurements of the electrical parameters of the MOS transistor that has completed visual inspection.

[0015] The technical effects and advantages of this invention are as follows: 1. This test fixture for MOSFET processing, through a feedback control system consisting of a pressure sensor, elastic element, controller, and clamping drive mechanism, can monitor and precisely control the clamping force acting on the MOSFET in real time. When the pressure sensor detects that the force value reaches the preset threshold, the controller immediately instructs the drive mechanism to stop, thereby keeping the clamping force constant within a safe and suitable range. Moreover, the clamping components are detachable and quick to replace, making it easy to adapt to various product models. The clamping is stable during testing, the operation is simple and fast, and the accuracy of testing and product safety are improved.

[0016] 2. This test fixture for MOSFET processing adopts a combination of detachable clamping components and a rotary positioning mechanism. On the one hand, the clamping components can be quickly assembled and disassembled by the cooperation of the plug and the slot. On the other hand, the multifaceted structure of the rotary table allows multiple sets of different clamping components to be pre-installed, and switching can be completed by rotation and angle locking. This dual modular design enables the same fixture to quickly adapt to the testing of MOSFETs with different package types, greatly reducing downtime for changeover.

[0017] 3. The test fixture for MOSFET processing has a rubber block on the main body of the clamp and its special slot, which provides a positioning surface with good containment and anti-slip properties for the MOSFET. The constant clamping force ensures that the relative position of the device and the slot remains unchanged each time it is clamped, thereby ensuring the stability of the testing process. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a three-dimensional structural diagram of the present invention; Figure 3 This is a top view of the present invention; Figure 4 This is a bottom view of the present invention; Figure 5 This is a disassembly diagram of the rotary table of the present invention; Figure 6 This is a disassembled schematic diagram of the clamp body of the present invention; Figure 7 This is a cross-sectional schematic diagram of the sleeve of the present invention; Figure 8 This is a schematic diagram of the pressure sensor of the present invention.

[0020] In the diagram: 1. Tooling base; 2. Transverse slide; 21. Drive motor; 22. Bidirectional screw; 23. Rail; 24. Elastic element; 25. Pressure sensor; 3. Movable table; 4. Bearing frame; 5. Limiting frame; 6. Rotary table; 61. Rotating shaft; 62. Slot; 7. Clamp body; 71. Rubber block; 72. Slot; 73. Insert block; 74. Fitting ball; 8. Controller; 9. Rotary disk; 91. Angle positioning hole; 92. Sleeve; 93. Adjusting screw; 94. Slider; 95. Locking rod. Detailed Implementation

[0021] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This embodiment discloses a test fixture for MOSFET processing, in conjunction with the attached... Figure 1 To be continued Figure 8 As shown, the device includes a fixture base 1, a clamping drive mechanism, at least two clamping units arranged opposite each other, a constant force control mechanism, a controller 8, and replaceable clamping assemblies. The clamping drive mechanism, mounted on the fixture base 1, drives the clamping units to move towards or away from each other to clamp and release the MOSFET. The constant force control mechanism is connected to at least one clamping unit to provide buffering during clamping and to monitor the clamping force in real time. The controller 8 is electrically connected to the clamping drive mechanism and the constant force control mechanism to receive force signals and control the drive action. Clamping assemblies are detachably mounted at the ends of the clamping units for direct adaptation and contact with different types of MOSFETs.

[0023] According to the appendix Figure 1 Appendix Figure 2 and appendix Figure 8 As shown, the clamping drive mechanism specifically includes a transverse slide 2, a drive motor 21, and a bidirectional screw 22 mounted on the fixture base 1. The main body of the drive motor 21 is fixed to the fixture base 1, and its output shaft is connected to the bidirectional screw 22. The bidirectional screw 22 is configured as two segments with opposite threads, and is threadedly connected to the two transverse slides 2 respectively. When the drive motor 21 operates, it drives the bidirectional screw 22 to rotate, thereby causing the two transverse slides 2 to move linearly towards or away from each other along the fixture base 1, which in turn drives the clamping unit mounted on the transverse slides 2 to move synchronously.

[0024] According to the appendix Figure 1 Appendix Figure 3 and appendix Figure 8As shown, each clamping unit includes a movable platform 3, a support frame 4, and a limiting frame 5, which are fixedly connected in sequence. The movable platform 3 is slidably connected to the transverse slide 2. The constant force control mechanism further includes a track 23 disposed inside the transverse slide 2, an elastic element 24 sleeved on the track 23, and a pressure sensor 25 disposed at the end of the track 23. The elastic element 24 is preferably a rubber elastic block, but can also be a spring. The bottom of the movable platform 3 has a groove that mates with the track 23, allowing it to slide along the track 23. During clamping, when the clamping assembly contacts the MOS transistor, a further driving force will cause the movable platform 3 to slide relative to the transverse slide 2, thereby compressing the elastic element 24. The pressure sensor 25 is disposed at the end of the elastic element 24 and is used to detect the reaction force generated by the compression of the elastic element 24 in real time, i.e., the actual clamping force, and convert this force signal into an electrical signal and transmit it to the controller 8.

[0025] According to the appendix Figure 1 Appendix Figure 4 and appendix Figure 5 As shown, the clamping assembly is mounted on the limiting frame 5 via a rotary positioning mechanism. The rotary positioning mechanism includes a rotating shaft 61 fixed to the limiting frame 5 and a rotating table 6 rotatably connected to the rotating shaft 61 via bearings. The clamping assembly is mounted on the outer surface of the rotating table 6. By rotating the rotating table 6, the spatial angle of the clamping assembly can be changed to adapt to different test postures or to change different clamping surfaces.

[0026] According to the appendix Figure 4 Appendix Figure 5 and appendix Figure 7 As shown, the rotary positioning mechanism also includes a precision mechanical angle locking assembly for fixing the rotary table 6 at the desired angle. The angle locking assembly includes a rotary disk 9 fixedly connected to the bottom of the rotating shaft 61 and rotating synchronously, a sleeve 92 fixedly mounted on the support frame 4, an adjusting screw 93 threadedly connected to the sleeve 92, and a slider 94 slidably disposed within the inner cavity of the sleeve 92. The end of the adjusting screw 93 is rotatably connected to the slider 94 via a bearing. Multiple angle positioning holes 91 are equidistantly or as needed on the periphery of the rotary disk 9. A locking rod 95 is fixedly connected to the slider 94. When the adjusting screw 93 is rotated, the slider 94 can be driven to move linearly within the sleeve 92. When locking is required, rotating the adjusting screw 93 forward pushes the slider 94 and the locking rod 95 forward, causing the tip of the locking rod 95 to insert into the corresponding angle positioning hole 91 on the rotary disk 9, thereby preventing the rotary disk 9 and the rotating shaft 61 from rotating and fixing the angle. Rotating the adjusting screw 93 in the opposite direction will retract the locking rod 95 and release the rotating disc 9.

[0027] According to the appendix Figure 5As shown, the rotary table 6 is specifically constructed as a polyhedral structure, such as a regular hexahedron; the figure shows a regular octahedron. Clamping components suitable for different types of MOSFETs can be pre-installed on at least two, or even all, of its sides. By rotating the rotary table 6 and fixing it using the angle locking components, the target clamping components can be quickly switched to the working position, enabling rapid switching between multiple MOSFET models at the same workstation and greatly improving testing speed.

[0028] According to the appendix Figure 5 and appendix Figure 6 As shown, the clamping assembly specifically includes a clamp body 7. The clamp body 7 is quickly and detachably connected to the side of the rotary table 6 via a plug-in assembly. The plug-in assembly includes a slot 62 formed on the side of the rotary table 6 and a plug block 73 fixed to the back of the clamp body 7. The plug block 73 is provided with a resilient snap-fit ​​element. During installation, the plug block 73 is aligned and inserted into the slot 62; when the plug block 73 is inserted into place, the resilient snap-fit ​​element automatically engages with the inner wall of the slot 62 or the snap hole on the rotary table 6 to achieve a snap-fit ​​fixation and prevent it from falling off.

[0029] According to the appendix Figure 6 As shown, a preferred embodiment of the resilient snap-fit ​​element disclosed herein is a locking ball 74. The insert 73 has an internal receiving cavity in which a spring and the locking ball 74 are placed. The spring pushes a portion of the locking ball 74 outward, causing it to protrude from the surface of the insert 73. Correspondingly, a recessed latch is formed on the inner wall of the slot 62. When the insert 73 is inserted into the slot 62 to a predetermined position, the protruding locking ball 74 is engaged in the latch under the action of the spring, producing a distinct click and achieving mechanical locking, ensuring a secure and reliable connection. For disassembly, sufficient pulling force is applied to overcome the spring force and retract the locking ball 74, allowing the insert 73 to be pulled out.

[0030] According to the appendix Figure 6 As shown, it is particularly important to emphasize that a rubber block 71 is bonded or embedded on the clamping surface of the clamping body 7. The rubber block 71 is soft in texture, which can both protect the surface of the MOSFET and increase friction. More importantly, a slot 72 that precisely matches the shape of the specific model of MOSFET to be tested is precisely formed on the clamping surface of the rubber block 71. The shape and depth of the slot 72 are designed to limit and contain the plastic package of the MOSFET, ensuring that its position is stable during clamping and testing, without displacement or rotation, thus improving the repeatability and accuracy of the test.

[0031] According to the appendix Figure 1 To be continued Figure 8As shown, it is particularly important to emphasize that the entire working principle and process of the test fixture are coordinated and controlled by the controller 8. The controller 8 receives real-time force signals from the pressure sensor 25 and compares them with a preset safe clamping force threshold. When the detected force value reaches the preset threshold, the controller 8 immediately sends a stop command to the drive motor 21, thereby achieving precise constant force clamping. This control method effectively avoids the problems of damaging the MOSFET due to excessive clamping force or loosening due to insufficient clamping force.

[0032] Example 1: This example uses the testing of a standard TO-220 packaged MOSFET as an example, combined with the attached... Figure 1 To be continued Figure 8 The workflow is explained in detail below: Preparation and Installation: The operator selects a pair of matching clamping assemblies according to the size of the TO-220 MOSFET to be tested. Align the insert 73 of the clamping assembly with the slot 62 on the side of the rotary table 6 and insert it until a "click" sound is heard as the fitting ball 74 engages, completing the installation. If other clamps are already installed on other sides of the rotary table 6, the target clamp can be oriented towards the inward working position by rotating and locking the rotary disk 9.

[0033] Place the workpiece: Place the TO-220 packaged MOS transistor to be tested between two opposing clamping components, so that its encapsulation is roughly aligned with the slot 72 on the rubber block 71.

[0034] Start clamping: Start the test program via the human-machine interface of controller 8 or an external signal. Controller 8 controls the drive motor 21 to rotate forward, which drives the two transverse slides 2 and the entire clamping unit to move in opposite directions via the bidirectional screw 22.

[0035] Constant force clamping is achieved by the rubber blocks 71 on the clamping assembly contacting both sides of the MOSFET. As the drive continues, the movable stage 3 begins to slide along the track 23, compressing the elastic element 24. The pressure sensor 25 detects the compression force in real time and transmits it to the controller 8. When the force value reaches the preset threshold set for the TO-220 MOSFET, the controller 8 immediately cuts off the power to the drive motor 21, and the clamping action stops. At this time, the MOSFET is stably and gently clamped between the two sets of slots 72, with a constant clamping force.

[0036] Test execution: While maintaining the clamped state, an industrial camera mounted above the fixture first performs visual inspection of the MOSFET's pin coplanarity, markings, etc. Subsequently, a diode measurement probe or other electrical test probe carried by a robotic arm contacts specific pins of the MOSFET, and physical measurements of electrical parameters such as conduction voltage and threshold voltage are completed under the coordination of controller 8.

[0037] Release and Replacement: After the test is completed, the controller 8 controls the drive motor 21 to reverse, causing the clamping units to move in opposite directions and releasing the MOSFET. The tested MOSFET can then be removed, and the next MOSFET to be tested can be inserted, repeating the above process. If it is necessary to replace the MOSFET with a different package, step 1 should be performed to replace the corresponding clamping assembly.

[0038] Example 2: This example uses the testing of a MOS transistor in a non-standard package or with a special size as an example, combined with the attached... Figure 1 To be continued Figure 8 The quick switchover process is explained in detail below. Quick Switching Preparation: Assume that a fixture for the common package A is installed on side A of the rotary table 6, and a fixture for the common package B is installed on side B. The MOSFET to be tested is a non-common package C.

[0039] Selection and positioning: The operator manually rotates the rotary table 6 to rotate the empty C-face to the working position facing inward.

[0040] Angle locking: Rotate the adjusting screw 93 to push the locking rod 95 into the angle positioning hole 91 on the rotating disk 9 corresponding to the angle, and firmly lock the rotating table 6 to prevent it from rotating during the test.

[0041] Install the special fixture: The pre-made special clamping component suitable for packaging C, namely the clamp body 7, is installed onto the C surface of the rotary table 6, which has been rotated into place, through the cooperation of the insert block 73 and the slot 62.

[0042] Subsequent testing: Subsequently, steps 2 to 6 in Example 1 can be followed to complete the placement, constant force clamping, visual inspection and electrical measurement of the packaged C-type MOS transistor.

[0043] Restore initial configuration: After the test is completed, the special fixture for the C side can be removed, and the rotary table 6 can be rotated back to the commonly used A or B side and locked to cope with subsequent large-scale routine test tasks.

[0044] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test fixture for MOSFET processing, characterized in that, include: Tooling base (1); A clamping drive mechanism is disposed on the tooling base (1); At least two clamping units arranged opposite each other are connected to the clamping drive mechanism, which is used to drive the at least two clamping units to move towards or away from each other; A constant force control mechanism is connected to at least one of the clamping units, the constant force control mechanism including an elastic element (24) and a pressure sensor (25), the elastic element (24) being used to provide elastic cushioning, and the pressure sensor (25) being used to detect clamping force; The controller (8) is electrically connected to the clamping drive mechanism and the pressure sensor (25) and is used to control the clamping drive mechanism to stop when the force value detected by the pressure sensor (25) reaches a preset threshold. A replaceable clamping assembly is detachably disposed at the end of the clamping unit for direct contact with and clamping of the MOS transistor.

2. The testing fixture for MOSFET processing according to claim 1, characterized in that, The clamping drive mechanism includes a transverse slide (2), a drive motor (21) and a bidirectional screw (22) disposed on the tooling base (1). The drive motor (21) is connected to the bidirectional screw (22), and the bidirectional screw (22) is threadedly connected to the transverse slide (2).

3. The test fixture for MOSFET processing according to claim 2, characterized in that, Each clamping unit includes a movable platform (3), a support frame (4), and a limiting frame (5) connected in sequence. The movable platform (3) is slidably connected to the transverse slide (2). The constant force control mechanism also includes a track (23) set on the transverse slide (2). The movable platform (3) slides along the track (23) and compresses or releases the elastic element (24). The pressure sensor (25) is set at the end of the elastic element (24) or the end of the track (23).

4. The test fixture for MOSFET processing according to claim 3, characterized in that, The clamping assembly is mounted on the limiting frame (5) via a rotary positioning mechanism; The rotary positioning mechanism includes a rotating shaft (61) fixed on the limiting frame (5) and a rotating table (6) rotatably connected to the rotating shaft (61), and the clamping assembly is mounted on the rotating table (6).

5. The test fixture for MOSFET processing according to claim 4, characterized in that, The rotary positioning mechanism also includes an angle locking component; The angle locking assembly includes a rotating disk (9) that rotates synchronously with the rotating shaft (61), a sleeve (92) disposed on the support frame (4) or the limiting frame (5), an adjusting screw (93) threadedly connected to the sleeve (92), and a slider (94) slidably disposed in the sleeve (92) and rotatably connected to the end of the adjusting screw (93). The rotating disk (9) has multiple angle positioning holes (91) around its periphery. A locking rod (95) is fixed on the slider (94). Rotating the adjusting screw (93) can drive the slider (94) to slide, so that the locking rod (95) can be inserted into or removed from the angle positioning hole (91).

6. The test fixture for MOSFET processing according to claim 5, characterized in that, The rotary table (6) is a polyhedral structure, with different clamping components installed on at least two of its sides.

7. The test fixture for MOSFET processing according to claim 4, characterized in that, The clamping assembly includes a clamping body (7), which is detachably connected to the rotary table (6) via a plug-in assembly; The plug-in assembly includes a slot (62) disposed on the rotary table (6) and a plug (73) disposed on the clamp body (7). The plug (73) is provided with an elastic snap-fit ​​member. When the plug (73) is inserted into the slot (62), the elastic snap-fit ​​member snaps and fixes itself to the slot (62) or the rotary table (6).

8. The test fixture for MOSFET processing according to claim 7, characterized in that, The elastic snap-fit ​​component is a snap-fit ​​ball (74). The insert block (73) has a receiving cavity and a spring inside. The snap-fit ​​ball (74) protrudes from the surface of the insert block (73) and can snap-fit ​​into the recess of the inner wall of the slot (62).

9. The test fixture for MOSFET processing according to claim 8, characterized in that, The clamping surface of the clamping body (7) is provided with a rubber block (71), and the rubber block (71) is provided with a slot (72) that matches the shape of the MOS tube to be tested.

10. A method for testing MOSFETs using the test fixture described in any one of claims 1-9, characterized in that, The steps include: Step S1, select and install the corresponding clamping assembly to the end of the clamping unit according to the model of the MOSFET under test; Step S2: Place the MOS transistor under test between the two sets of oppositely arranged clamping components; Step S3: The clamping drive mechanism is activated by the controller (8) to drive the two sets of clamping units to move towards each other, so that the clamping components contact and clamp the MOS transistor; In step S4, during the clamping process, the elastic element (24) of the constant force control mechanism is compressed, and the pressure sensor (25) detects the clamping force in real time and feeds it back to the controller (8). Step S5: When the force value detected by the pressure sensor (25) reaches the preset threshold, the controller (8) controls the clamping drive mechanism to stop, thereby achieving constant force clamping. Step S6: Use a vision inspection device set above the fixture to perform visual inspection on the appearance or pin position of the MOSFET under constant force clamping. Step S7: Use a measurement probe to perform physical measurements of the electrical parameters of the MOS transistor that has completed visual inspection.

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