Method and device for detecting redundant substances in inner cavity of sealed electronic component

Abstract

The invention discloses a method and a device for detecting redundant substances in an inner cavity of a sealed electronic component, and belongs to the field of reliability testing of electronic components. A corresponding test circuit is designed according to the specific sealed electronic component; manufacturing a PCB test board for batch component detection according to the test circuit; fixing the PCB test board on a vibration table by a clamp; placing and fixing a batch of to-be-tested components in a tool test seat on the PCB test board according to requirements; inputting a test signal to the PCB test board under a vibration condition; collecting an output signal of each component; and comparing with a component output signal standard value, judging and analyzing, and judging whether each component has inner cavity redundancy or not according to the abnormal condition of the output signal of each component. The problems of low detection precision and low detection efficiency of tiny particles in an inner cavity of an existing sealed electronic component and redundant substances generated by electrochemical pollution are solved. The device is widely applied to the detection technology of sealing electronic components and sealing electronic module inner cavity redundancy.

Description

Technical Field

[0001] The present invention belongs to the field of reliability testing of electronic components, and further relates to the field of detection of foreign matters in the cavity of sealed electronic components. Specifically, it relates to a method and device for detecting foreign matters in the cavity of sealed electronic components. Background Art

[0002] In high-reliability electronic equipment, such as aerospace electronic equipment, the reliability of electronic components is directly related to the stable operation of the entire electronic equipment. The presence of foreign matters in the cavity of electronic components may cause types of faults such as short circuits, decreased insulation resistance, performance degradation, and change of logic functions during the operation of electronic equipment. Since the current electronic component manufacturing industry cannot completely eliminate the presence of foreign matters in the cavity, during the product manufacturing process, it is inevitable that some metal chips, solder particles, dust, aluminum sheets, etc. are sealed in the product cavity, as well as foreign matters generated by chemical reactions inside the cavity when the water vapor and oxygen content inside the device are too high. Therefore, the detection of foreign matters in the cavity of electronic components has always been a concern of component manufacturers and the aerospace electronic equipment field.

[0003] Currently, the commonly used methods for detecting foreign matters in the cavity of sealed electronic components in the domestic and foreign electronic component-related industrial fields are the PIND method and the MATRA method. The PIND method, whose Chinese name is the particle impact noise detection method, works by placing the product to be tested in a vibration environment at a certain frequency and detecting whether the component will generate stress elastic waves and sound waves due to the presence of moving foreign matters inside. Although the PIND method can efficiently and accurately check whether there are floating foreign matters inside the component, it does not accurately screen for foreign matters stuck inside the cavity and foreign matters generated by chemical reactions inside the cavity. The MATRA method can only check whether there are conductive particles inside the cavity by monitoring static parameters such as the contact resistance and insulation resistance between the contacts of the component, and the detection efficiency and accuracy are low.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to solve the problems of low detection accuracy and low detection efficiency for the foreign matters generated by tiny particulate matters and electrochemical pollution in the cavity of existing sealed electronic components.

[0006] To this end, the present invention provides a method for detecting foreign matters in the cavity of sealed electronic components, including the following steps: (1) Design a corresponding test circuit according to the specific sealed electronic component.

[0007] (2) Fabricate a PCB test board for batch component detection according to the test circuit.

[0008] (3) Fix the PCB test board on the vibration table by means of a fixture.

[0009] (4) Place and fix the components to be tested in batches in the tooling test sockets on the PCB test board as required.

[0010] (5) Input a test signal to the PCB test board under vibration conditions.

[0011] (6) Collect the output signals of each component.

[0012] (7) Compare with the standard value of the component output signal and make a judgment and analysis. When there are tiny particles and excess substances generated by electrochemical contamination inside the component cavity, the output signal of the component will be affected in a high-frequency vibration environment. According to the abnormality of the output signal of each component, it is possible to efficiently and accurately judge whether there are excess substances in the inner cavity of each component.

[0013] The device for detecting excess substances in the inner cavity of a sealed electronic component, as Figure 1 shown. It includes: a drive control module, a test signal, a vibration table, a fixing fixture, a PCB test board, a device under test (DUT), and a detection table.

[0014] The PCB test board is fixed on the vibration table by a fixing fixture. There are 2 or more devices under test (DUTs), which are placed in the corresponding tooling test sockets on the PCB test board according to the set positions. The drive control module is respectively connected to the detection table and the PCB test board. The test signal is connected to the signal input end of the PCB test board. The signal output end of the PCB test board is connected to the signal acquisition module of the detection table.

[0015] The drive control module provides a voltage source for the signal acquisition module and the PCB test board, and at the same time reads the converted test digital signal of the signal acquisition module and sends it to the detection computer of the detection table for storage and processing and analysis.

[0016] The test signal is a voltage signal output by a signal generator and serves as the input signal for the device under test. The type and magnitude of the test signal are determined by the type of the device under test.

[0017] The vibration table vibrates vertically up and down perpendicular to the ground.

[0018] The fixing fixture is used to fix the PCB test board to the vibration table surface.

[0019] The PCB test board is a test circuit device connecting the test signal and the device under test. There are multiple (at least 2) test stations on the PCB board, and each test station is designed with an independent test circuit.

[0020] The detection platform includes a signal acquisition module and a detection computer. Each analog input channel of the signal acquisition module is connected to the output detection terminals of each component to be tested on the PCB test board. The detection computer is used to view the measurement results of each component, and after the end of a vibration cycle, check whether there is any abnormality in the detection information of each station on the PCB test board, so as to determine whether there are foreign matters in the internal cavity of the component under test.

[0021] The technical effects of the present invention are as follows: It can simultaneously detect floating or fixed tiny particles and foreign matters generated by electrochemical contamination in the inner cavity of sealed electronic components, perform batch detection, with high detection accuracy, high detection efficiency, good batch consistency, batch repeatability, and batch reliability.

[0022] It can be widely applied to the detection technology of foreign matters in the inner cavities of sealed electronic components and sealed electronic modules. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the principle structure of a detection system and device for foreign matters in the inner cavity of a sealed electronic component.

[0024] Figure 2 It is a schematic diagram of the principle structure of the drive control module.

[0025] Figure 3 It is a schematic diagram of the structure of the 5V power conversion circuit of the drive control module.

[0026] Figure 4 It is a schematic diagram of the structure of the 3.3V power conversion circuit of the drive control module.

[0027] Figure 5 It is a schematic diagram of the structure of the 1.5V power conversion circuit of the drive control module.

[0028] Figure 6 It is a schematic diagram of the simplified model structure of the vibration table.

[0029] Figure 7 It is a schematic diagram of the model structure of the PCB test board fixing fixture.

[0030] Figure 8 It is a schematic diagram of the simplified structure of the PCB test board.

[0031] Figure 9 It is a schematic diagram of the principle structure of the signal acquisition module.

[0032] Figure 10 It is a schematic diagram of the test circuit structure of the FH541 type power amplifier on the PCB test board.

[0033] In the figure: 1 is the vibration table box body, 2 is the moving coil table top, 3 are the table top screws, 4 are the vibration table screw holes on the table top, 5 are the Y-direction vibration screw holes for fixing the PCB test board, 6 are the X-direction vibration screw holes for fixing the PCB test board, and 7 are the Z-direction vibration screw holes for fixing the PCB test board. Specific implementation method

[0034] As Figures 1-10 shown, the method and device for detecting the excess matter in the inner cavity of a sealed electronic component are as follows: I. Driving control module The driving control module includes an FPGA, a level converter, a power converter, an RS422 interface circuit, and 4 groups of high-speed SRAMs. The FPGA reads and writes the register data in the signal sampling module through the level converter, transfers the data to the 4 groups of high-speed SRAMs, and controls the RS422 interface circuit to transmit the data to the detection computer. At the same time, it controls the power conversion module to provide rated voltage sources with different values, and the rated voltage sources are connected to the signal acquisition module through the power interface. As Figure 2 shown.

[0035] The level converter performs signal conversion between different voltage levels to accurately transmit the different digital voltage signals transmitted in the signal sampling module.

[0036] The power conversion module is built with an LT3045 chip. The input voltage range is 1.8V to 20V, and the adjustable output voltage is 0V to 15V. The output voltages of 1.5V, 3.3V, and 5V provide voltage sources for the signal acquisition module, the FPGA, and the PCB test board respectively. As Figure 3 、 4 、5 shown.

[0037] In the power conversion module: The input pins IN, EN / UV, and PGFB of the LT3045EMSE#PBF are connected in parallel to the 1.8V to 20V positive power supply. The positive power supply is also connected in parallel to the filter capacitors C2 and C3 and then grounded. The PG pin is left floating, the GND and ILIM pins are grounded, the output pins OUT and OUTS are connected in parallel as the voltage output port, the output end is connected to the C1 filter capacitor and then grounded, and the output voltage is adjusted by the resistance value of the resistor R9 connected to the SET pin. As Figure 3 shown, when 50.5kΩ is connected, the output voltage is +5V. As Figure 4 shown, when 33.2kΩ is connected, the output voltage is +3.3V. As Figure 5 shown, when 15kΩ is connected, the output voltage is +1.5V.

[0038] The RS422 interface circuit A is used to issue test instructions (such as online adjustment of the sampling rate, SCLK clock cycle, switching between the timing test mode and the continuous test mode), and the RS422 interface circuit B is used to send the test data to the detection computer for storage and processing analysis.

[0039] The high-speed SRAM is used for caching the sampled data. After the test is completed, all the collected data will be sent to the detection computer for storage and processing.

[0040] II. Vibration Table The vibration modes of the vibration table include sine vibration, random vibration, and combined sine and random vibration. The vibration direction is vertical up and down with respect to the ground. As Figure 6 shown.

[0041] III. Fixed Fixture The fixed fixture is used to fix the PCB test board to the vibration tabletop. On the top and side surfaces of the fixed fixture, there are respectively made screw holes for fixing the PCB test board, namely the vibration tabletop screw hole 4, the Y-direction vibration screw hole 5 for fixing the PCB test board, the X-direction vibration screw hole 6 for fixing the PCB test board, and the Z-direction vibration screw hole 7 for fixing the PCB test board. As Figure 7 shown. When the PCB test board is fixed on the top surface of the fixture, the components under test vibrate along the Y-axis direction of the vibration table; when the PCB test board is fixed horizontally on the side surface of the fixture, the components under test vibrate along the X-axis direction of the vibration table; when the PCB test board is fixed vertically on the side surface of the fixture, the components under test vibrate along the Z-axis direction of the vibration table.

[0042] The test method for the X, Y, and Z axial vibrations of the components under test is as follows: First, fix the PCB test board in the Y-direction vibration screw hole and test the output signal of the components under test when vibrating along the Y-axis direction; then fix the PCB test board horizontally in the X-direction vibration screw hole and test the output signal of the components under test when vibrating along the X-axis direction; finally, fix the PCB test board vertically in the Z-direction vibration screw hole and test the output signal of the components under test when vibrating along the Z-axis direction.

[0043] IV. PCB Test Board As Figure 8 shown, the PCB test board is a test circuit device connecting the test signal and the components under test. Different types of components under test are configured with different PCB test boards. The PCB board contains m×n test workstations, and the specific number of workstations depends on the size of the components under test and the size of the PCB test board. Here, m is the number of rows of test workstations, and n is the number of columns of test workstations. A test socket is welded to each test workstation for the components under test to be placed or removed without damage.

[0044] Each test station of the PCB test board is designed with independent test circuits. The power supply terminals, ground terminals, and input terminals of all the test circuits of the stations are connected in parallel, that is, all the stations on the PCB test board share a power supply, ground, and input signal, but each station contains a separate output detection port.

[0045] V. Components to be tested There are 2 or more components to be tested. Each component to be tested is connected to the PCB test board through a test socket on the PCB. The component to be tested is fixed on the PCB test board through the pressing cap device of the test socket to ensure that the pins of each component to be tested are reliably connected to the PCB test board under vibration conditions.

[0046] VI. Detection platform As Figure 1 shown, the detection platform includes a signal acquisition module and a detection computer.

[0047] The signal acquisition module is based on multiple AD7091R-8 analog-to-digital converters, which has the advantages of low power consumption, high-speed sampling (up to a throughput rate of 1MSPS), high resolution, and a high-speed serial interface, etc., to achieve efficient and high-precision signal sampling. Each AD7091R-8 contains 8 analog input channels, and each analog input channel is connected to the output detection terminals of each component to be tested on the PCB test board. Thus, the number of AD7091R-8 in the signal acquisition module is determined by the number of components to be tested in a single inspection set in advance. As Figure 9 shown.

[0048] The power supply voltage VDD range for normal operation of the AD7091R-8 in the signal acquisition module is 2.7V to 5.25V, and the logic voltage input Vdrive operating range is 1.8V to 5V, which is controlled by providing a constant voltage source through the power supply module in the drive control module. All the high-speed serial interfaces (SPI) of the AD7091R-8 are connected in parallel, and all the input analog signals collected can be completely read. All the CONVST ports are connected in parallel, and chip selection is performed through the CS port. Finally, data reading and processing are carried out through the FPGA in the drive control module.

[0049] The detection computer is used to view the measurement results of each component. After the end of a vibration cycle, check whether there is any abnormality in the detection information of each station on the PCB test board through the detection computer, so as to judge whether there are any foreign objects in the internal cavity of the component under test.

[0050] Application example: Take the detection of foreign objects in the internal cavity of a sealed device FH541 type power amplifier of Guizhou Zhenhua Fengguang Semiconductor Co., Ltd. as an example.

[0051] The PCB test board equipped with the FH541 type power amplifier to be tested contains 16 stations, and 16 FH541 type power amplifiers can be tested simultaneously. An independent test circuit for the FH541 type power amplifier is designed on each station of the test board, as Figure 10 shown. The FH541 test circuit is a non-inverting amplifier circuit with a magnification factor of 10. The non-inverting input terminals, inverting input terminals, grounding terminals, positive power supply terminals, and negative power supply terminals of each station on the PCB test board are connected in parallel, and the output terminal OUTA of each station is used as a detection port separately.

[0052] Before the test starts, place 16 FH541 type power amplifiers to be tested in the station test seats on the PCB test board. First, fix the PCB test board in the vibration screw holes in the Y-axis direction. After the installation is completed, the drive control module provides voltage sources of 1.5V, 3.3V, and 5V to the signal acquisition module, FPGA unit, and PCB test board respectively. Then, the signal generator sends a sine input signal with a peak-to-peak value of 5Vpp and a frequency of 100kHz to the PCB test board. Finally, turn on the vibration table to adjust the random vibration mode, and the vibration time is one cycle. The output waveforms of the FH541 type power amplifiers in each test station within one vibration cycle are collected through the detection station. Once the inspection computer finds that the output signal of the device in a certain station shows obvious abnormalities during the vibration process, or the output waveform of the device in a certain station is different from that of a normal component, it is determined that there are foreign substances in the inner cavity of the device in that station.

[0053] If after a random vibration cycle in the Y-axis direction, the inspection computer checks and finds that the output waveforms of the devices in all stations are normal, turn off the power of all modules, remove the PCB test board from the vibration screw holes in the Y-axis direction and re-fix it in the vibration screw holes in the X-axis direction, and repeat the above operations. If the output waveforms of the devices are normal during the random vibration cycle in the X-axis direction, continue with the random vibration test in the Z-axis direction. When all FH541 type power amplifier devices pass the random vibration cycles in the Y, X, and Z-axis directions and the inspection computer does not find abnormal output waveforms in a certain station, all the test devices are qualified. Once the inspection computer finds abnormal output waveforms of the devices during any of the above axial tests, it is determined that there are foreign substances in the inner cavity of the device.

[0054] Finally, it should be noted that the above embodiments are merely examples given for clear illustration. The present invention includes but is not limited to the above embodiments, and it is not necessary and impossible to list all implementation manners here. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. All implementation manners that meet the requirements of the present invention fall within the protection scope of the present invention.

Claims

1. A method for detecting foreign matters in the inner cavity of a sealed electronic component, characterized in that, It includes the following methods: (1) Design a corresponding test circuit according to specific sealed electronic components; (2) Fabricate a PCB test board for batch component detection based on the test circuit; (3) Fix the PCB test board on a vibration table by a fixture; (4) Place and fix the batch of components to be tested in the tooling test sockets on the PCB test board as required; (5) Input a test signal to the PCB test board under vibration conditions; (6) Collect the output signals of each component; (7) Compare with the standard value of the component output signal, judge and analyze. According to the abnormal conditions of the output signals of each component, determine whether there are excess materials in the inner cavity of each component.

2. The device for detecting excess materials in the inner cavity of a sealed electronic component according to claim 1, wherein: It includes a drive control module, a test signal, a vibration table, a fixing fixture, a PCB test board, components to be tested, and a detection table; The PCB test board is fixed on the vibration table by a fixing fixture. There are 2 or more components to be tested, which are placed in the corresponding tooling test sockets on the PCB test board at set positions. The drive control module is respectively connected to the detection table and the PCB test board. The test signal is connected to the signal input end of the PCB test board. The signal output end of the PCB test board is connected to the signal acquisition module of the detection table; The drive control module provides a voltage source for the signal acquisition module and the PCB test board, and at the same time reads the converted test digital signal of the signal acquisition module and sends it to the detection computer of the detection table for storage and processing analysis; The test signal is a voltage signal output by a signal generator and serves as the input signal of the component to be tested. The type and magnitude of the test signal are determined by the type of the component to be tested; The vibration table vibrates vertically up and down relative to the ground; The fixing fixture is used to fix the PCB test board to the vibration table surface; The PCB test board is a test circuit device connecting the test signal and the component to be tested. There are at least 2 test stations on the PCB test board, and each test station is designed with an independent test circuit; The detection table includes a signal acquisition module and a detection computer. Each analog input channel of the signal acquisition module is connected to the output detection end of each component to be tested on the PCB test board; the detection computer is used to view the measurement results of each component. After the end of a vibration cycle, check whether the detection information of each station on the PCB test board is abnormal through the detection computer, so as to judge whether there are excess materials in the inner cavity of the measured component.

3. The device for detecting excess materials in the inner cavity of a sealed electronic component according to claim 2, wherein: The drive control module includes an FPGA, a level converter, a power conversion, an RS422 interface circuit, and 4 groups of high-speed SRAMs; The FPGA completes the reading and writing of the register data in the signal sampling module through the level converter, transfers the data to 4 groups of high-speed SRAMs, and controls the RS422 interface circuit to transmit the data to the detection computer. At the same time, it controls the power conversion module to provide rated voltage sources with different values. The rated voltage sources are connected to the signal acquisition module through a power interface; The level converter converts signals between different voltage levels to accurately transmit different digital voltage signals transmitted in the signal sampling module; The input voltage range of the power conversion module is 1.8V to 20V, and the adjustable output voltage is 0V to 15V; the voltages of 1.5V, 3.3V, and 5V are output to provide voltage sources for the signal acquisition module, FPGA, and PCB test board respectively; The RS422 interface circuit A is used to issue test instructions, and the RS422 interface circuit B is used to send test data to the detection computer for storage and processing analysis; The high-speed SRAM is used for caching sampled data, and all the collected data will be sent to the detection computer for storage and processing after the test is completed.

4. The device for detecting foreign matters in the inner cavity of a sealed electronic component according to claim 3, wherein: The power conversion module is built with an LT3045 chip. The input pins IN, EN / UV, and PGFB of the LT3045 are connected in parallel and connected to the 1.8V to 20V positive power supply. The positive power supply is also connected to the parallel filter capacitors C2 and C3 and then grounded. The PG pin is left floating, the GND and ILIM pins are grounded, the output pins OUT and OUTS are connected in parallel as the voltage output port, the output terminal is connected to the C1 filter capacitor and then grounded, and the output voltage is adjusted by the resistance value of the resistor R9 connected to the SET pin. When the resistance of 50.5kΩ is connected, the output voltage is +5V; when the resistance of 33.2kΩ is connected, the output voltage is +3.3V; when the resistance of 15kΩ is connected, the output voltage is +1.5V.

5. The device for detecting foreign matters in the inner cavity of a sealed electronic component according to claim 2, wherein: The vibration mode of the vibration table is sinusoidal vibration, random vibration, or a combination of sinusoidal vibration and random vibration, and the vibration direction is up and down perpendicular to the ground.

6. The device for detecting foreign matters in the inner cavity of a sealed electronic component according to claim 2, wherein: The PCB test board has m×n test stations. The specific number of test stations depends on the size of the component to be tested and the size of the PCB test board. Here, m is the number of rows of test stations, and n is the number of columns of test stations. A test socket is installed for the component to be tested on each test station, and the component to be tested is placed or removed from the test socket without damage; Each test station of the PCB test board is provided with an independent test circuit. The power supply terminals, ground terminals, and input terminals of all the test circuits of the stations are connected in parallel, and each station has a separate output detection port.

7. The device for detecting foreign matters in the inner cavity of a sealed electronic component according to claim 2, wherein: The top surface of the fixed fixture is a plane, parallel to the vibration table surface; the side surface is a plane, perpendicular to the vibration table surface; the bottom surface is a plane, parallel to the vibration table surface, and the part of the bottom surface extending out of the side surface is used for screw fixation with the vibration table surface; Vibration table screw holes (4) are made on the bottom surface of the fixed fixture, screw holes for fixing the PCB test board in the Y-direction vibration (5) are made on the top surface, and screw holes for fixing the PCB test board in the X-direction vibration (6) and screw holes for fixing the PCB test board in the Z-direction vibration (7) are made on the side surface; when the PCB test board is fixed on the top surface of the fixture, the device under test vibrates along the Y-axis direction of the vibration table; when the PCB test board is fixed horizontally on the side surface of the fixture, the device under test vibrates along the X-axis direction of the vibration table; when the PCB test board is fixed vertically on the side surface of the fixture, the device under test vibrates along the Z-axis direction of the vibration table.

8. The device for detecting the foreign matter in the inner cavity of a sealed electronic component according to claim 7, characterized in that: The method for vibrating the device under test along the X, Y, and Z axes is as follows: First, fix the PCB test board in the screw hole for Y-direction vibration, and test the output signal of the device under test when vibrating along the Y-axis; then fix the PCB test board horizontally in the screw hole for X-direction vibration, and test the output signal of the device under test when vibrating along the X-axis; finally, fix the PCB test board vertically in the screw hole for Z-direction vibration, and test the output signal of the device under test when vibrating along the Z-axis.

9. The device for detecting the foreign matter in the inner cavity of a sealed electronic component according to claim 2, characterized in that: The device under test is connected to the PCB test board through the test socket on the PCB board, and the device under test is fixed on the PCB test board through the compression cap device of the test socket.

10. The device for detecting the foreign matter in the inner cavity of a sealed electronic component according to claim 2, characterized in that: The signal acquisition module is composed of more than 2 AD7091R-8 analog-to-digital converters, and the number of AD7091R-8 is determined by the number of devices under test to be inspected each time preset; each AD7091R-8 has 8 analog input channels, and each analog input channel is connected to the output detection end of each device under test on the PCB test board; the normal operating power supply voltage VDD range of AD7091R-8 is 2.7V~5.25V, and the logic voltage input Vdrive operating range is 1.8V~5V, which is controlled by providing a constant voltage source through the power supply module in the drive control module; all the high-speed serial interfaces (SPI) of AD7091R-8 are connected in parallel to completely read all the input analog signals collected, all the CONVST ports are connected in parallel, and chip selection is performed through the CS port, and finally data reading and processing are performed through the FPGA in the drive control module; The detection computer is connected to the signal acquisition module to view the measurement results of each component. After the end of a vibration cycle, check whether there is any abnormality in the detection information of each station on the PCB test board through the detection computer, so as to judge whether there is foreign matter in the inner cavity of the measured component.

Images