CN104730295A - Clamp for thermal resistance test of SMD packaged semiconductor device - Google Patents

Abstract

The invention discloses a jig for testing thermal resistance of an SMD packaged semiconductor device, which relates to the technical field of semiconductor testing; it includes a metal base, a PCB circuit board, an insulating positioning block and a pressing block, the metal base is provided with a groove, and the PCB circuit board Placed in the groove, the PCB circuit board is provided with an insulating positioning block, and the insulating positioning block body is provided with a positioning hole suitable for the SMD device to be tested. The pressing block of the device; the bottom of the groove is provided with a thermocouple probe placement hole corresponding to the electrode position of the SMD device under test; the side of the groove is provided with two electrode wiring holes, and the PCB circuit board is provided with two The electrode that connects the pins of the SMD device under test to the electrode wiring hole. The invention can ensure good thermal conductivity between the tested SMD device and the constant temperature platform, is beneficial to control the shell temperature within the required range, and at the same time ensures the insulation between electrodes of the tested SMD device to ensure normal measurement.

Description

A jig for testing thermal resistance of SMD packaged semiconductor devices

technical field

The invention relates to the technical field of semiconductor testing.

Background technique

The thermal characteristics of semiconductor devices are one of the important contents in reliability design. In order to ensure the reliability of the device in use, the structural design of the device should consider the heat dissipation characteristics of the device, and the quantitative calculation of these designs needs to be based on the thermal resistance parameters of the device. Therefore, the thermal resistance of a semiconductor device is an important parameter reflecting the thermal characteristics of the device.

The resistance encountered by heat on the heat conduction path is thermal resistance. It is defined as the ratio of the temperature difference on the heat conduction path to the power consumption. The thermal resistance of the device junction to the case is the thermal resistance between the heat source junction of the chip and the package case, that is: . The junction temperature T _J of the device can be obtained through the thermal resistance tester. According to the test method specified in the test standard, when performing the junction-to-case thermal resistance test, the temperature of the device's package case (that is, the case temperature) is controlled by the temperature control platform. For a fixed temperature, the junction-to-case thermal resistance of the device can be obtained.

For semiconductor devices packaged in SMD (Surface Mount Devices, Surface Mount Devices), the three electrodes are all located on the bottom of the device and on the same plane. Since the part with a higher shell temperature during operation is the bottom of the lead-out electrodes, the control shell When the temperature is high, the electrode surface needs to be attached to the temperature control platform and the thermocouple probe, but the temperature control platform is made of metal. If the device is directly attached to the temperature control platform, the test will inevitably be impossible due to the short circuit of the electrodes.

Contents of the invention

The technical problem to be solved by the present invention is to provide a thermal resistance test fixture for SMD packaged semiconductor devices, which ensures good thermal conductivity between the tested SMD device and the constant temperature platform, which is conducive to controlling the temperature of the shell within the required range, and at the same time ensures that the measured SMD The electrodes of the device are insulated to ensure the normal measurement; the positioning is simple and accurate, and the installation is convenient, so that the rapid measurement of the thermal resistance of SMD packaged semiconductor devices is realized, and it is suitable for the thermal resistance test of SMD packaged semiconductor devices of various sizes and models.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

A thermal resistance test fixture for an SMD packaged semiconductor device, comprising a metal base, a PCB circuit board, an insulating positioning block and a pressing block, the metal base is provided with a groove, the PCB circuit board is placed in the groove, and the PCB circuit board is above There is an insulating positioning block, and the insulating positioning block body is provided with a positioning hole suitable for the tested SMD device, and the insulating positioning block is provided with a pressing block that can press down the tested SMD device; the bottom of the groove is set There are thermocouple probe placement holes corresponding to the electrode positions of the SMD device under test; two electrode wiring holes are provided on the side of the groove, and two wiring holes are provided on the PCB circuit board to connect the pins of the SMD device under test to the electrodes. electrodes connected to the holes.

In a further technical solution, the pressing block is T-shaped, and the lower part is provided with a protrusion, and the protrusion presses the SMD device under test downward, and the two ends of the pressing block are fixed on the edge of the groove by screws.

In a further technical solution, the structure of the insulating positioning block is adapted to the groove, and at least one pair of opposite sides of the insulating positioning block is provided with a hand-held concave notch.

In a further technical solution, the PCB circuit board is a nickel-plated gold circuit board, and the thickness of the PCB circuit board is 0.5mm. The nickel-plated gold circuit board is used for fast heat conduction, which is beneficial to the heat transfer between the tested SMD device and the constant temperature platform.

In a further technical solution, the insulating positioning block and the pressing block are made of polytetrafluoroethylene. Different from rigid insulating materials, the compression block is made of polytetrafluoroethylene, considering that the thermal conductivity of polytetrafluoroethylene is similar to that of air. Using this material can imitate the actual working state of the device under test as much as possible. Avoid introducing a new heat dissipation path to the device under test in the working state, and polytetrafluoroethylene has a certain degree of elasticity. After the two sides of the pressing block are fixed, it can exert a certain force on the SMD device under test under the protrusion.

In a further technical solution, conductive silver paste or conductive paper is coated between the PCB circuit board and the groove.

In a further technical solution, base fixing holes are provided on both sides of the metal base for fixing the base on the constant temperature platform.

In a further technical solution, a number of heat dissipation holes are provided around the electrodes of the PCB circuit board and at positions corresponding to the SMD device to be tested, and the diameter of the heat dissipation holes is 0.5 mm.

In a further technical solution, the metal base is made of copper, which has good thermal conductivity and low cost; the thickness of the bottom of the groove is 1 mm, which ensures faster heat transfer between the SMD device under test and the constant temperature platform.

In a further technical solution, an insulator is installed in the electrode wiring hole. Since the base is made of copper, the insulator is installed so that the wire is insulated from the metal base when passing through the side wall of the groove, so as to ensure the reliability and safety of the test; There are non-nickel-plated gold insulating channels on the side, which are set along the electrodes and work together with the insulators to avoid short-circuiting of the two electrodes.

The beneficial effect produced by adopting the above-mentioned technical scheme is that the present invention ensures good thermal conductivity between the tested SMD device and the constant temperature platform, which is conducive to controlling the temperature of the shell within the required range, and at the same time ensures the insulation between the electrodes of the tested SMD device, Guarantee the normal progress of the measurement; and the positioning is simple and accurate, easy to install, and realize the rapid measurement of the thermal resistance of SMD packaged semiconductor devices, which is suitable for the thermal resistance test of SMD packaged semiconductor devices of various sizes and models; Apply power to the tested SMD device, while preventing the electrical connection between the tested SMD device and the metal base, and the heat dissipation holes provided can dissipate the heat of the tested SMD device to the metal base, thereby ensuring heat transfer with the constant temperature platform; the metal base It is made of copper, low in cost, and has good heat conduction effect; it is equipped with a pressing block that can exert pressure on the SMD device under test, so as to ensure good electrical contact and heat transfer between the SMD device under test and the PCB circuit board, and ensure the test work It can be carried out smoothly; the provided insulating positioning block can realize fast positioning and improve work efficiency.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is a structural schematic diagram of the PCB circuit board in Fig. 1;

In the drawings: 1. Metal base, 2. PCB circuit board, 3. Insulation positioning block, 4. SMD device under test, 5. Compression block, 6. Screw, 7. Base fixing hole, 8. Electrode wiring hole , 9, screw hole, 10, thermocouple probe placement hole, 11, cooling hole, 12, insulation channel, 13, electrode, 14, groove, 15, positioning placement hole.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

As shown in FIG. 1 , a jig for testing thermal resistance of an SMD packaged semiconductor device includes a metal base 1 , a PCB circuit board 2 , an insulating positioning block 3 and a pressing block 5 . The metal base 1 is made of copper, and the metal base 1 is provided with a groove 14, and the thickness of the bottom of the groove 14 is 1mm. The PCB circuit board 2 is placed in the groove 14, and the conductive silver paste or conductive paper is coated between the PCB circuit board 2 and the groove 14. The PCB circuit board 2 is a nickel-plated gold circuit board, and the thickness of the PCB circuit board 2 is 0.5mm, the nickel-plated gold circuit board has good thermal conductivity, which is beneficial to the heat transfer between the tested SMD device 4 and the constant temperature platform. The PCB circuit board 2 is provided with an insulating positioning block 3, and the structure of the insulating positioning block 3 is adapted to the groove 14. The surrounding edges of the insulating positioning block 3 are provided with arc-shaped hand-held concave gaps, which are convenient for testing from the metal base 1 Take out and put in. The body of the insulating positioning block 3 is provided with positioning and placing holes 15 that are compatible with the SMD device 4 to be tested. A pressing block 5 capable of pressing down the SMD device 4 under test is arranged on the insulating positioning block 3 . The pressing block 5 is T-shaped, and the lower part is provided with a protrusion, and the protrusion presses the SMD device 4 to be tested downward, and the two sides of the pressing block 5 and the groove 14 are provided with screw holes 9 matching the screws 6 , The two ends of the pressing block 5 are fixed on the edge of the groove 14 by screws 6 . The insulation positioning block 3 and the compression block 5 are made of polytetrafluoroethylene, and the compression block 5 is made of polytetrafluoroethylene, considering that the thermal conductivity of polytetrafluoroethylene is similar to that of air, and this material can be used Try to imitate the actual working state of the device under test to avoid introducing a new heat dissipation path for the device under test in working state, and polytetrafluoroethylene has a certain degree of elasticity. Test the SMD device 4 to apply a certain force. The bottom of the groove 14 is provided with a thermocouple probe placement hole 10 corresponding to the position of the electrode 13 of the SMD device 4 to be tested. Two electrode connection holes 8 are arranged on the side of the groove 14, and insulators are installed in the electrode connection holes 8.

As shown in FIG. 2 , two electrodes 13 connecting the 4 pins of the SMD device under test to the electrode wiring hole 8 are arranged on the PCB circuit board 2 , and non-nickel-plated gold insulating channels 12 are arranged on both sides of the electrodes 13 . Both sides of the metal base 1 are provided with base fixing holes 7, and the metal base 1 is fixed on the constant temperature platform through the base fixing holes 7. Around the electrode 13 of the PCB circuit board 2 and at the corresponding position with the tested SMD device 4, there are several cooling holes 11. The diameter of the cooling holes 11 is 0.5mm. around the edge position. The position and quantity of the heat dissipation holes 11 can be set according to the actual situation, so as to ensure that the PCB circuit board 2 has good heat dissipation performance.

The method of use of the present invention is: before use, the PCB circuit board 2 is first contacted with the bottom of the groove 14 through conductive silver paste or conductive paper and pressed tightly; Connect the two electrodes 13; during the test, apply thermal conductive silicone grease between the lower surface of the metal base 1 and the constant temperature platform, insert the thermocouple probe into the thermocouple probe placement hole 10, place the metal base 1 on the constant temperature platform, and then put Insulation positioning block 3 and the tested SMD device 4, heat-conducting silicone grease and other materials are applied between the tested SMD device 4 and the PCB circuit board 2; then the pressed block 5 is used to press the tested SMD device 4, and the screw 6 is used to connect and compress Block 5 and metal base 1, firmly fix the metal base 1 on the constant temperature platform, apply external electrical conditions to the wire protruding from the electrode wiring hole 8 and the metal base 1 that is connected to the largest electrode of the SMD device 4 under test Above, the test can be carried out by applying electrical test conditions to the SMD device 4 under test.

The principle of the present invention is: the heating electrode of the tested SMD device 4 is close to the PCB circuit board 2, and materials such as thermal conductive silicone grease are applied between the two during use to improve the heat conduction effect; coating between the PCB circuit board 2 and the base Conductive silver paste or a layer of conductive paper, conductive silver paste or conductive paper has conductivity, and also has good thermal conductivity; during the test, the heat of the heating electrode of the tested SMD device 4 passes through the nickel-plated gold PCB circuit board 2 tightly Arranged heat dissipation holes 11, conductive silver paste or conductive paper, metal base 1 to the constant temperature platform, and then control the temperature of the electrode surface shell of the SMD device 4 under test; apply electrical conditions to the two electrodes 13 and the metal base 1, and the electrode 13 The two electrodes 13 of the tested SMD device 4 and the largest electrode that is in contact with the metal base 1 are energized and start to work; the thermocouple probe is located directly below the largest electrode of the tested SMD device 4 to detect heat dissipation through the PCB circuit board 2 The temperature of the heat in the hole 11 realizes the purpose of measuring the temperature of the shell of the electrode surface of the SMD device 4 under test.

Claims (10)

1. a SMD encapsulated semiconductor device thermo-resistance measurement fixture, it is characterized in that comprising metab (1), PCB (2), insulation locating piece (3) and compact heap (5), described metab (1) is provided with groove (14), PCB (2) is placed in groove (14), PCB (2) is provided with insulation locating piece (3) above, insulation locating piece (3) body is provided with the location putting hole (15) suitable with tested SMD device (4), insulation locating piece (3) is provided with the compact heap (5) that can compress tested SMD device (4) downwards above, groove (14) bottom is provided with the thermocouple probe putting hole (10) corresponding with electrode (13) position of tested SMD device (4), described groove (14) side is provided with two electrode connection holes (8), and described PCB (2) is provided with two electrodes (13) be connected with electrode connection hole (8) by tested SMD device (4) pin.

2. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, it is characterized in that described compact heap (5) is T-shaped, bottom is provided with projection, tested SMD device (4) compresses downwards by described projection, and compact heap (5) two ends are fixed on the groove of groove (14) along upper by screw (6).

3. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, it is characterized in that described insulation locating piece (3) structure and groove (14) suitable, insulation locating piece (3) at least one group of opposite side be provided with hand-held interior concane gap.

4. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, it is characterized in that described PCB (2) is for plating nickel gold circuit board, the thickness of PCB (2) is 0.5mm.

5. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, is characterized in that described insulation locating piece (3) and compact heap (5) are teflon material.

6. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, is characterized in that scribbling conductive silver paste between described PCB (2) and groove (14) or being covered with conductive paper.

7. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, is characterized in that described metab (1) both sides are provided with base fixed orifice (7).

8. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, it is characterized in that electrode (13) surrounding of described PCB (2) and be provided with some louvres (11) with tested SMD device (4) correspondence position, the diameter of described louvre (11) is 0.5mm.

9. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, it is characterized in that described metab (1) is copper material, described groove (14) bottom thickness is 1mm.

10. a kind of SMD encapsulated semiconductor device thermo-resistance measurement fixture according to claim 1, it is characterized in that being provided with insulator in described electrode connection hole (8), described electrode (13) both sides are provided with the insulated channel (12) of non-plating nickel gold.