Clamp for testing reliability of flat-plate type power semiconductor device

Abstract

The invention relates to a flat plate type power semiconductor device reliability test fixture, which comprises a pressure applying frame, a pressure applying structure and a lower pressure head preheating structure are connected onto the pressure applying frame, the lower pressure head preheating structure supports a tested device, the pressure applying structure is connected with an upper pressure head staggered layer insulation structure, and the upper pressure head staggered layer insulation structure is connected with the lower pressure head preheating structure. The pressure applying structure can enable the upper pressure head staggered layer insulation structure to move downwards, and pressure is applied to the tested device through the upper pressure head staggered layer insulation structure; the beneficial effects of the invention are that a pressure applying structure of a trapezoid screw-nut pair is adopted, so that the reliability of the test fixture aiming at long-time operation is effectively guaranteed. The layout of the preheating system is designed in the standard profile radiator, and the fan is designed behind the standard profile radiator for sufficient air cooling and heat dissipation of the radiator, so that the structure is more compact, simpler and more effective.

Description

Technical Field

[0001] The invention belongs to the field of power semiconductor testing, and in particular relates to a flat-plate power semiconductor device reliability testing fixture. Background Art

[0002] At present, flat-type power semiconductor devices are widely used as a mature electronic switch. In the device production process, various parameters need to be tested, among which reliability tests for devices are indispensable, such as high-temperature blocking test, thermal cycle load test, etc. This type of reliability test first requires the device under test to be clamped in a fixture, and the fixture is required to provide certain high-temperature preheating and heat dissipation conditions at the same time. Secondly, according to the test standard, the external test power supply intermittently applies high voltage or high current to the device under test, and then physically cools it down. By analogy, the device under test needs to be repeatedly subjected to the above test cycles, which can last from two to three hours to dozens of days. During this process, the device under test needs to be kept in a stable clamped state, so it is necessary to provide a stable and reliable test fixture to ensure long-term test operation. Summary of the invention

[0003] The object of the present invention is to provide a fixture which can stably clamp a flat-type power semiconductor device, thereby realizing reliability testing thereof.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by this patent is a flat-plate type power semiconductor device reliability test fixture, including a pressure frame, a pressure structure and a lower pressure head preheating structure are connected to the pressure frame, the lower pressure head preheating structure supports the device under test, and the pressure structure is connected to the upper pressure head staggered insulation structure, the pressure structure can move the upper pressure head staggered insulation structure downward, and apply pressure to the device under test through the upper pressure head staggered insulation structure; a rotatable trapezoidal screw is connected to the center position of the sliding plate, and the trapezoidal screw moves axially when rotating, thereby controlling the vertical movement of the sliding plate; the lower pressure head preheating structure includes a heat sink and a fan, the device under test is placed on the heat sink, the lower electrode of the device under test is led out through the heat sink, the heat sink is built with a heating rod and a thermocouple, the heating rod and the thermocouple heat the device under test when working, and the fan is located on the side of the heat sink, and the fan can blow air to the heat sink and the device under test to reduce the temperature of the heat sink and the device under test.

[0005] Furthermore, a leveling structure is connected between the pressure-applying structure and the upper pressure head staggered insulating structure, and the leveling structure is located above the upper pressure head staggered insulating structure.

[0006] Furthermore, the leveling structure includes a first isolation plate, which is connected to the upper pressure head staggered insulation structure, and the first isolation plate is connected to the sliding plate through a third screw. A conical hole is provided on the upper surface of the first isolation plate, and a steel ball is provided in the conical hole.

[0007] Furthermore, a buffer spring is sleeved on the third screw rod, and the buffer spring is located between the sliding plate and the first isolation plate.

[0008] Furthermore, the upper pressure head staggered insulation structure includes a second isolation plate and an upper electrode, the upper electrode is butted on the second isolation plate, and the upper electrode can be pressed on the tested object after moving downward.

[0009] Furthermore, the pressure frame includes a bottom plate and a top plate, and the bottom plate and the top plate are connected by two guide rods.

[0010] The beneficial effects of this patent are: the pressure structure of the trapezoidal screw nut pair is adopted to effectively ensure the reliability of the test fixture for long-term operation. The layout of the preheating system is designed in the standard profile radiator, and a fan is designed behind it to provide sufficient air cooling for the radiator, making the structure more compact, simple and effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a front view of the present invention;

[0012] Figure 2 is a side view of the present invention;

[0013] Figure 3 It is a partial enlarged view of the pressure-applying end of the trapezoidal screw rod of the present invention;

[0014] Among them, 1-top plate, 2-trapezoidal nut, 3-fourth screw, 4-sliding plate, 5-fifth screw, 6-linear bearing, 7-fan, 8-guide rod, 9-heating baffle, 10-fan bracket, 11-sixth screw, 12-third isolation plate, 13-bottom plate, 14-fixed angle connector, 15-radiator, 16-heating rod, 17-eighth screw, 18-thermocouple, 19-device under test, 20-upper electrode, 21-second isolation plate, 22-first isolation plate, 23-buffer spring, 24-third threaded rod, 25-second screw, 26-bearing end cover, 27-first screw, 28-trapezoidal lead screw. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various configurations. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention. In the embodiments, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various 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 application claimed for protection, but merely represents the selected embodiments of the present application.

[0016] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "back" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0017] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" 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 directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0018] See also Figures 1 to 3As shown, a flat-plate type power semiconductor device reliability test fixture includes a pressure frame, which includes a bottom plate 13 and a top plate 1. The bottom plate 13 and the top plate 1 are connected by two guide rods 8, so that there is a vertical spacing area between the bottom plate 13 and the top plate 1. Specifically, the two guide rods 8 are screwed into and fastened on the bottom plate 13 by threads. The upper parts of the two guide rods 8 have steps and threads. The top plate 1 is installed on the steps of the upper ends of the guide rods 8 and then fastened with two nuts. In this way, the pressure frame forms an integral body. The pressure frame is provided with a pressure structure and a lower pressure head preheating structure, both of which are located in the vertical spacing area. The pressure structure is located above the lower pressure head preheating structure. During the test, the device under test is placed on the lower pressure head preheating structure, and then pressure is applied to it to stabilize the position of the device under test, and then the reliability test of the device under test is carried out.

[0019] The two linear bearings 6 are symmetrically installed on both sides of the sliding plate 4 through a hole-shaft tight fit, and then installed through the two guide rods 8.

[0020] The pressure structure includes a sliding plate 4, on which a symmetrically arranged linear bearing 6 is tightly fitted through a hole axis, and a guide rod 8 passes through the linear bearing 6 to connect the sliding plate 4 with the guide rod 8 on the pressure frame. At this time, the sliding plate 4 can slide vertically in the vertical interval area, and the sliding plate 4 is connected with a trapezoidal screw rod 28, which passes through the top plate 1. The lower surface of the top plate 1 is connected with a trapezoidal nut 2 through a first screw 27, and the trapezoidal screw rod 28 passes through the trapezoidal nut 2, and the two are screwed together. When the trapezoidal screw rod 28 rotates, it can move axially, which will drive the sliding plate 4 to move vertically. A leveling structure is connected to the sliding plate 4, and an upper pressure head staggered insulation structure is connected to the leveling structure. The leveling structure is located above the upper pressure head staggered insulation structure, and both are located between the sliding plate 4 and the lower pressure head preheating structure. When the sliding plate 4 moves downward, the upper pressure head staggered insulation structure can be moved downward and finally pressed on the device under test;

[0021] A stepped hole shaft is provided at the center position of the upper surface of the above-mentioned sliding plate 4, and the stepped hole shaft is connected to the lower end of the trapezoidal screw 28, and a ball bowl set 31 is installed at the lower end of the trapezoidal screw 28, and a thrust bearing 32 is provided between the lower end of the trapezoidal screw 28 and the stepped hole shaft, and at this time, a bearing end cover 26 is connected to the sliding plate 4 through a second screw 25, and the bearing end cover 26 buckles the ball bowl set 31, the lower end of the trapezoidal screw 28 and the thrust bearing 32 together on the sliding plate 4, when the trapezoidal screw 28 is pressurized downward, its lower rod end contacts and presses the upper part of the thrust bearing 32; when the trapezoidal screw 28 is lifted up to relieve pressure, its lower rod end contacts the ball bowl set 31, and this design structure effectively reduces the friction loss of the rod end of the trapezoidal screw 28 during pressurization and decompression, making the clamp lighter and more convenient to work;

[0022] The above-mentioned leveling structure includes a first isolation plate 22, a conical hole is provided at the center of the upper surface of the first isolation plate 22, a steel ball 33 is installed in the conical hole, and when the first isolation plate 22 is docked with the sliding plate 4, the sliding plate 4 and the first isolation plate 22 clamp the steel ball 33, a third threaded rod 24 passes through the sliding plate 4, the third threaded rod 24 is connected to the first isolation plate 22, and a buffer spring 23 is sleeved on the third threaded rod 24, and at the same time, the first isolation plate 22 is docked with the upper pressure head staggered insulation structure;

[0023] The upper pressure head staggered insulation structure includes a second isolation plate 21 and an upper electrode 20. The second isolation plate 21 is located between the first isolation plate 22 and the upper electrode 20. The second isolation plate 21 is connected to the first isolation plate 22 by a fourth screw 3, and the upper electrode 20 is docked on the second isolation plate 21 by a fifth screw 5. After the sliding plate 4 moves downward, the upper electrode 20 also moves downward, and finally the upper electrode 20 is pressed on the test piece. At this time, the lower part of the test piece is supported by the lower pressure head preheating structure, so that the test piece is clamped in a stable state.

[0024] The lower pressure head preheating structure includes a radiator 15, which is placed on the third isolation plate 12, and the third isolation plate 12 is installed on the bottom plate 13. The radiator 15 is connected to the third isolation plate 12 through a fixed angle connector 14 and a sixth screw 11. The radiator 15 is provided with a side opening, and a heating rod 16 and a thermocouple 18 are inserted through the side opening, and then a heating baffle 9 is docked at the side opening, and the heating baffle 9 is fastened to the radiator 15 with four eighth screws 17. A small hole for passing the heating rod 16 and the thermocouple 18 cables is reserved on the heating baffle 9, and the cables of the two can be led out and passed through;

[0025] When the test fixture is working, the device under test 19 is first placed on the heat sink 15, and then the trapezoidal screw 28 is controlled to rotate so that the trapezoidal screw 28 moves downward, thereby driving the components below the sliding plate 4 to apply downward pressure until they are pressed on the upper surface of the device under test 19. When controlling the trapezoidal screw 28 to rotate, it can be manually controlled, for example, a rotary handle 29 is fixed at the upper end of the trapezoidal screw 28, or a tool can be inserted into the circular hole at the upper end of the trapezoidal screw 28, and then the tool is rotated to drive the trapezoidal screw 28; the upper end of the trapezoidal screw 28 can also be designed as an external hexagonal structure, and the trapezoidal screw 28 can be driven to rotate by an electric tool torque wrench. The above three methods can drive the trapezoidal screw 28 to rotate and move downward.

[0026] When necessary, use a torque wrench to apply pressure to the required pressure value of the device. The upper surface of the device under test 19 is one of its electrodes, which is led out through the upper electrode 20; the lower surface of the device under test 19 is another electrode, which is led out through the heat sink 15, and then turn on the heating function. The heating rod 16 and the thermocouple 18 can realize precise preheating and temperature control of the device under test 19 before testing. The external power supply is led out through the two electrodes to carry out reliability test on the current flow of the device under test.

[0027] A fan 7 is installed on the bottom plate through a fan bracket 10. The fan bracket 10 is fixed to the bottom plate 13 through the seventh screw 30. The fan 7 is located on the side of the radiator 15. When the fan 7 is working, it can blow air to the radiator 15. During the test, when the temperature of the device under test 19 exceeds the specified temperature, the fan 7 is started to cool down the upper electrode 20, the device under test 19 and the radiator 15, so that the temperature of the device under test 19 is constant at the specified temperature. At this time, the fan is stopped, and then the current is passed to make the device heat up to the junction temperature, and then the fan is restarted to cool down. This reciprocating cycle continues, and the purpose of reliability operation of the device under test is achieved.

[0028] In the above control, the fan, the heating rod and the thermocouple can be connected to an existing controller to realize the working state control.

[0029] In addition, in the present application, the upper electrode 20 of the test fixture is docked on the second isolation plate 21, and the second isolation plate 21 is connected to the first isolation plate 22, and the first isolation plate 22 is connected to the sliding plate 4 through three third screws 24, and the three third screws 24 are connected to the first isolation plate 22 after passing through the sliding plate 4 and the corresponding buffer springs 23. By adjusting the connection depth of the three third screws 24 and the first isolation plate 22 respectively, the parallelism between the lower surface of the upper electrode 20 and the upper surface of the radiator 15 can be ensured in the no-load state. The steel ball 33 is arranged in the conical hole in the center of the upper surface of the first isolation plate 22. This structure can ensure the swing clearance of the upper electrode in the circumferential direction when pressure is applied. It effectively overcomes the disadvantage of insufficient parallelism between the lower surface of the upper electrode 20 and the upper surface of the radiator 15 caused by the cumulative assembly error when pressure is applied.

[0030] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in 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 flat-type power semiconductor device reliability test fixture, comprising a pressure frame, characterized in that: The pressure frame is connected to a pressure structure and a lower pressure head preheating structure, the lower pressure head preheating structure supports the device under test, and the pressure structure is connected to an upper pressure head staggered insulation structure, the pressure structure can move the upper pressure head staggered insulation structure downward, and apply pressure to the device under test through the upper pressure head staggered insulation structure; The pressure structure includes a sliding plate, a rotatable trapezoidal screw is connected to the center of the sliding plate, and the trapezoidal screw controls the vertical movement of the sliding plate when rotating; The lower pressure head preheating structure includes a radiator and a fan. The device under test is placed on the radiator. The lower electrode of the device under test is led out through the radiator. The radiator is equipped with a heating rod and a thermocouple. The heating rod and the thermocouple heat the device under test when working. The fan is located at the side of the radiator, and the fan can blow air to the radiator and the device under test to reduce the temperature of the radiator and the device under test.

2. A flat-plate power semiconductor device reliability test fixture according to claim 1, characterized in that: A leveling structure is connected between the pressure-applying structure and the upper pressure head staggered insulating structure, and the leveling structure is located above the upper pressure head staggered insulating structure.

3. A flat-plate power semiconductor device reliability test fixture according to claim 2, characterized in that: The leveling structure includes a first isolation plate, which is connected to the upper pressure head staggered insulation structure, and is connected to the sliding plate through a third screw. The upper surface of the first isolation plate is provided with a conical hole, and a steel ball is provided in the conical hole.

4. A flat-plate power semiconductor device reliability test fixture according to claim 3, characterized in that: The third screw rod is sleeved with a buffer spring, which is located between the sliding plate and the first isolation plate.

5. A flat-plate power semiconductor device reliability test fixture according to claim 1 or 3, characterized in that: The upper pressure head staggered insulation structure comprises a second isolation plate and an upper electrode, the upper electrode is butted on the second isolation plate, and the upper electrode can be pressed on the tested object after moving downward.

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