Coaxial low-sensing test fixture
By designing a coaxial low-sensitivity test fixture, using a coaxial electrode structure and a stacked lead-out structure, the problem of high stray inductance in the test loop is solved, the test accuracy is improved and the test requirements of high temperature parameters is achieved, and the stray inductance in the test loop is reduced to 50nH, improving the accuracy and safety of the test.
Patent Information
- Application Number
- CN202421970672.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-14
- Publication Date
- 2025-07-29
- Estimated Expiration
- 2034-08-14
AI Technical Summary
The high amount of stray inductors in the loop of existing test equipment leads to insufficient testing accuracy of high-power semiconductors. A test fixture that can reduce the amount of stray inductors is urgently needed to improve testing accuracy.
Coaxial low-sensitivity test fixtures are adopted, including pressure frames, coaxial electrode structures and stacked lead-out structures. Through the coaxial electrode structure and stacked lead-out structure design, the stray inductance of the test loop is reduced and heating function is provided when needed.
Effectively reduce the distributed inductance of the test loop to about 50 nH, improve the test accuracy, and provide preheating function during high-temperature testing to ensure the accuracy and safety of the test results.
Smart Images
Figure CN223166787U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the field of semiconductor testing, and particularly relates to a coaxial low-inductance test fixture for testing high-power semiconductors. Background Art
[0002] At present, high-power semiconductors, as a kind of mature electronic switching semiconductor devices, are widely used. During their production process, various parameters need to be tested. Among them, the relevant dynamic parameters related to the turn-on and turn-off of the device under test are involved, and it is required that the parasitic inductance of the test circuit be minimized. Only by trying to reduce the stray inductance in the circuit can the true value of the dynamic parameters of the device be tested more objectively and accurately. Although the stray inductance in the circuit of the existing test equipment has reached the general requirements, it can still be further optimized and reduced to make the test results more accurate. Therefore, there is an urgent need for a test fixture that can improve the test accuracy. Summary of the Utility Model
[0003] The purpose of the utility model is to provide a coaxial low-inductance test fixture that can improve the test accuracy by reducing the stray inductance.
[0004] To achieve the above purpose, the technical solution adopted by the utility model is a coaxial low-inductance test fixture, which includes a pressure frame. A coaxial electrode structure is mounted on the pressure frame. The coaxial electrode structure includes an upper core electrode conduction structure and an outer coaxial electrode structure. The device under test is located between the outer coaxial electrode structure and the upper core electrode conduction structure, and the two clamp the device under test. The upper core electrode conduction structure includes an upper electrode, an upper insulating separator, and an upper electrode lead-out plate. The upper insulating separator and the upper electrode lead-out plate are both fastened to the upper electrode. An upper copper ring separator is arranged between the upper insulating separator and the upper electrode lead-out plate. The upper copper ring separator is connected with an upper copper ring electrode, and the upper copper ring electrode is sleeved on the upper electrode. A laminated lead-out structure is arranged on the upper core electrode conduction structure, and the laminated lead-out structure is connected with a power supply test cabinet. The laminated lead-out structure includes an upper electrode lead-out plate and a lower electrode lead-out plate. The upper electrode lead-out plate is connected with the power supply test cabinet through an upper electrode lead-out strip. One end of the lower electrode lead-out plate is connected with the upper copper ring electrode, and the other end is horizontally led out and connected to the power supply test cabinet. A laminated intermediate separator is clamped between the upper electrode lead-out strip and the lower electrode lead-out plate.
[0005] Further, the upper electrode lead-out strip is made of a soft braided copper strip, and an insulating isolation tube is sleeved on the upper electrode lead-out strip. The insulating isolation tube is clamped between the upper copper ring separator and the upper copper ring electrode.
[0006] Further, the outer coaxial electrode structure includes a lower insulating separator, a lower electrode conductive plate, and a lower electrode. The lower insulating separator and the lower electrode conductive plate are both fixed to the lower electrode.
[0007] Further, the lower electrode is connected with a lower copper ring separator, the upper end of the lower copper ring electrode is fixed with a wire spring pin, the wire spring pin is matched with a jack arranged at the lower end of the upper copper ring electrode, and when the peripheral coaxial electrode structure and the upper core electrode conduction structure clamp the device under test, the wire spring pin is inserted into the jack.
[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: through the design of the coaxial structure and the laminated structure, the stray inductance of the test circuit can be reduced to a relatively low value. After actual implementation and verification, the distributed inductance of the test circuit can be reduced to about 50 nH.
[0009] When the high-temperature parameters need to be tested simultaneously, the heating system can be turned on to heat the upper electrode and the lower electrode, thereby meeting the functional requirement of preheating the device under test. Description of the Drawings
[0010] Figure 1 is the front view of the present invention;
[0011] Figure 2 is the side view of the present invention;
[0012] Figure 3 is the partial enlarged view of the laminated lead-out structure of the present invention. Detailed Embodiment
[0013] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention. In the embodiments, the components of the embodiments of the present application usually described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application required to be protected, but only represents the selected embodiments of the present application.
[0014] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be an electrical connection; it can be a hydraulic oil circuit connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.
[0015] The utility model relates to a coaxial low-inductance test fixture, which is composed of three major parts: a pressure frame structure, a coaxial electrode structure, and a laminated lead-out structure.
[0016] According to Figure 1 and Figure 2 As shown: the coaxial electrode structure needs to be mounted on the pressure frame structure, and the pressure frame structure includes: an upper fixing plate 1, a movable plate 13, a lower fixing plate 15, a linear bearing 14, a guide post 8, a connecting flange 18, an oil cylinder 17, and a chassis 16, which are composed of 8 parts. Among them, the oil cylinder 17 is fixed under the lower fixing plate 15 through the upper surface flange, the piston rod of the oil cylinder 17 is connected to the movable plate 13 through the connecting flange, the upper fixing plate 1, the movable plate 13, and the lower fixing plate 15 are arranged parallel to each other, and two guide posts 8 are located on both sides of the frame and pass through the upper fixing plate 1, the movable plate 13, and the lower fixing plate 15 from top to bottom in sequence. The linear bearings 14 are arranged on both sides of the movable plate 13 to realize the up-and-down linear low-damping movement with the guide posts 8. The above parts together form the frame pressure structure, and the overall frame is located on the box body 16.
[0017] The above coaxial electrode structure includes: a backing plate 2, a first screw 34, a bolt 33, an upper copper ring isolation plate 3, a second screw 4, an upper copper ring positioning pin 5, an upper copper ring electrode 28, an upper insulation isolation plate 32, a third screw 31, an upper electrode lead-out plate 29, an upper electrode 27, an upper electrode heating lead-out plate 7, an upper electrode thermocouple 6, a wire spring pin 25, a tightening screw 24, a lower copper ring electrode 9, a lower insulation isolation plate 20, a lower electrode 22, a lower electrode heating lead-out plate 21, a lower electrode thermocouple 23, a lower electrode conductive plate 10, a sixth screw 35, a lower copper ring positioning pin 11, a lower copper ring isolation plate 12, a fourth screw 36, and a fifth screw 19. These components together form the coaxial electrode structure, and the specific coaxial electrode structure is divided into an upper core electrode conduction structure and a peripheral coaxial electrode structure;
[0018] The connection method of the upper core electrode conduction structure is as follows: The third screw 31 passes through the upper insulating separator 32 and the upper electrode lead-out plate 29 and is fastened to the upper electrode 27. There are electrode internal heating wire lead-out terminals arranged on the upper electrode heating lead-out plate 7 for externally connecting a heating power source. The upper electrode thermocouple 6 is screwed into the upper electrode 27 through its own thread structure to sample the heating temperature of the upper electrode 27. At this time, the upper insulating separator 32, the upper electrode lead-out plate 29, and the upper electrode 27 are assembled into a whole, forming the upper inner core electrode of the coaxial fixture. This whole part is fastened under the upper fixing plate 1 by 4 first screws 34. At the same time, an outer ring electrode is also connected. The specific connection method is as follows: 4 bolts 33 pass through the upper copper ring separator 3 and the backing plate 2 and are fastened under the upper fixing plate 1. The upper copper ring separator 3 and the upper copper ring electrode 28 are positioned by 2 upper copper ring positioning pins 5 and fastened together by 4 screws 4.
[0019] The above connection method is as follows: The sixth screw 35 passes through the lower insulating separator 20 and the lower electrode conductive plate 10 and is fixed to the lower electrode 22. There are electrode internal heating wire lead-out terminals arranged on the lower electrode heating lead-out plate 21 for externally connecting a heating power source. The lower electrode thermocouple 23 is screwed into the lower electrode 22 through its own thread structure to sample the heating temperature of the lower electrode 22. 4 fifth screws 19 fix the lower copper ring separator 12 to the movable plate 13. The lower copper ring positioning pin 11 passes through the lower copper ring separator 12, the lower electrode conductive plate 10, and the lower copper ring electrode 9 for precise positioning of the three. 4 fourth screws 36 pass through the lower copper ring separator 12, the lower electrode conductive plate 10, and the lower copper ring electrode 9 to fasten the three together. 30 wire spring pins 25 are evenly distributed at the upper end of the lower copper ring electrode 9 and are connected by screwing. 30 top screws 24 tightly hold the wire spring pins 25 on the side to prevent the wire spring pins from loosening and unscrewing.
[0020] According to Figure 3 As shown, the laminated lead-out structure includes: the upper electrode lead-out plate 29, the insulating isolation tube 39, the upper electrode lead-out tape 40, the laminated intermediate separator 37, and the lower electrode lead-out plate 38. The connection method is as follows: The upper electrode lead-out tape 40 is made of a soft braided copper tape. One end of the upper electrode lead-out tape 40 is fixed to the upper electrode lead-out plate 29 by 4 screws, and the other end passes through the insulating isolation tube 39 and leads to the power supply test cabinet. At the same time, the insulating isolation tube 39 is clamped between the upper copper ring separator 3 and the upper copper ring electrode 28. The lower electrode lead-out plate 38 is an L-shaped copper bar. One end of the lower electrode lead-out plate 38 is fixed to the outer surface of the upper copper ring electrode 28 by two screws, and the other end is horizontally led out to the power supply test cabinet. The laminated intermediate separator 37 is clamped between the upper electrode lead-out tape 40 and the lower electrode lead-out plate 38. In the test circuit, using the laminated lead-out structure can also effectively reduce the stray inductance in the circuit.
[0021] When this fixture is working, the device under test 26 is placed on the lower electrode 22. After the oil cylinder 17 operates, it pushes the movable plate 13 to drive the lower half of the coaxial electrode structure to rise. When the upper surface of the device under test 26 contacts the lower surface of the upper electrode 27, the 30 wire spring pins 25 on the lower copper ring electrode 9 just insert into the respective jacks of the upper copper ring electrode 28. The two main electrodes of the device under test 26 are its upper and lower surfaces respectively. At this time, the upper surface electrode of the device under test 26 is finally led out to the power supply test cabinet through the upper electrode 27, the upper electrode lead-out plate 29, and the upper electrode lead-out tape 40 in sequence; the lower surface electrode of the device under test 26 is finally led out to the power supply test cabinet through the lower electrode 22, the lower electrode conductive plate 10, the lower copper ring electrode 9, the 30 wire spring pins 25, the upper copper ring electrode 28, and the lower electrode lead-out plate 38 in sequence. To sum up, the two electrodes of the device under test 26 achieve coaxial lead-out of the test electrodes on the fixture platform. Outside the fixture, the upper electrode lead-out tape 40 and the lower electrode lead-out plate 38 are led out in parallel and laminated. Such a coaxial structure and laminated structure can reduce the stray inductance of the test circuit to a relatively low value. When high-temperature parameters need to be tested, the heating system can be turned on to heat the upper electrode 27 and the lower electrode 22, thereby meeting the functional requirement of pre-heating the device under test 26.
[0022] The present utility model proposes a solution using a coaxial electrode structure in the field of high-power semiconductor testing to solve the problem of large stray inductance in the test fixture circuit. The solution is centered around the device under test 26. The upper surface of the device under test is a main electrode, and the upper main electrode is led out through the upper electrode 27 and the upper electrode lead-out plate 29. The lower surface of the device under test is another electrode, and the lower main electrode is led out through the lower electrode 22, the lower electrode conductive plate 10, the lower copper ring electrode 9, the 30 wire spring pins 25, and the upper copper ring electrode 28. Thus, the electrical conduction structure of the upper and lower surface electrodes of the device under test forms a coaxial electrode structure with the upper surface conduction as the core and the lower surface conduction as the periphery.
[0023] In addition, the present utility model applies a laminated lead-out structure to the lead-out solution of the high-power semiconductor coaxial test fixture. The solution is that the upper electrode lead-out tape 40 is connected to the upper electrode lead-out plate 29 through screws, that is, the lead-out end of the upper surface of the device under test 26, forming the core of the coaxial structure. The upper electrode lead-out tape 40 passes through the insulating isolation tube 39 and is led out to the power supply test cabinet. One end of the lower electrode lead-out plate 38 is connected to the upper copper ring electrode 28, that is, the lead-out end of the lower surface of the device under test 26, forming the periphery of the coaxial structure. The other end of it is led out to the power supply test cabinet. The upper electrode lead-out tape 40 and the lower electrode lead-out plate 38 are separated by a laminated intermediate isolation plate 37 at the output periphery of the fixture. Thus, the lead-out of the upper electrode and the lower electrode forms a laminated lead-out structure.
[0024] Meanwhile, this coaxial low-inductance test fixture also takes into account the heating function of traditional test fixtures. Square openings and round holes are designed on the copper rings of the upper copper ring electrode 28 and the lower copper ring electrode 9 for the isolation passage of the heating electrodes and temperature acquisition of the upper electrode heating lead-out plate 7, the upper electrode thermocouple 6, the lower electrode heating lead-out plate 21, and the lower electrode thermocouple 23.
[0025] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A coaxial low-inductance test fixture, comprising a pressure frame, characterized in that: A coaxial electrode structure is mounted on the pressure frame. The coaxial electrode structure includes an upper core electrode conduction structure and a peripheral coaxial electrode structure. The device under test is located between the peripheral coaxial electrode structure and the upper core electrode conduction structure, and the two clamp the device under test. The upper core electrode conduction structure includes an upper electrode, an upper insulating separator, and an upper electrode lead-out plate. The upper insulating separator and the upper electrode lead-out plate are both fastened to the upper electrode. An upper copper ring separator is arranged between the upper insulating separator and the upper electrode lead-out plate. The upper copper ring separator is connected to an upper copper ring electrode, and the upper copper ring electrode is sleeved on the upper electrode. A stacked lead-out structure is arranged on the upper core electrode conduction structure, and the stacked lead-out structure is connected to the power supply test cabinet. The stacked lead-out structure includes an upper electrode lead-out plate and a lower electrode lead-out plate. The upper electrode lead-out plate is connected to the power supply test cabinet through an upper electrode lead-out strip. One end of the lower electrode lead-out plate is connected to the upper copper ring electrode, and the other end is horizontally led out and connected to the power supply test cabinet. A stacked intermediate separator is clamped between the upper electrode lead-out strip and the lower electrode lead-out plate.
2. The coaxial low-inductance test fixture according to claim 1, wherein: The upper electrode lead-out strip is made of a soft braided copper strip, and an insulating separator tube is sleeved on the upper electrode lead-out strip. The insulating separator tube is clamped between the upper copper ring separator and the upper copper ring electrode.
3. The coaxial low-inductance test fixture according to claim 1, wherein: The peripheral coaxial electrode structure includes a lower insulating separator, a lower electrode conductive plate, and a lower electrode. The lower insulating separator and the lower electrode conductive plate are both fixed to the lower electrode.
4. The coaxial low-inductance test fixture according to claim 3, wherein: The lower electrode is connected to a lower copper ring separator. The upper end of the lower copper ring electrode is fixed with a wire spring pin, and the wire spring pin is matched with a jack arranged at the lower end of the upper copper ring electrode. When the peripheral coaxial electrode structure and the upper core electrode conduction structure clamp the device under test, the wire spring pin is inserted into the jack.