JP4840942B2 - Electronic component leak inspection apparatus and electronic component leak inspection method - Google Patents

Description

  The present invention relates to an electronic component leak inspection apparatus and an electronic component leak inspection method according to an electronic component including an inertial body inside a hermetically sealed casing.

  Conventionally, as a sensor for detecting acceleration or angular acceleration, a piezoresistive sensor, a piezoelectric vibration gyro sensor, and the like are known. These sensors are configured to output a predetermined electrical signal when the internal inertial body is biased based on movement / vibration of the housing, that is, a part of the sensor is mechanically deformed.

  In these sensors, the housing is hermetically sealed so that the characteristics do not change under the influence of an activated gas or moisture. Therefore, in the manufacturing process of these sensors, a leak inspection for inspecting the airtightness of the housing is an essential process.

  Conventionally, in this leak inspection process, a bubble leak inspection method or the like is generally employed. The bubble leak inspection method is a method in which a product is put into a high-temperature inert liquid and a leak of gas sealed inside the product is confirmed as a bubble. According to this bubble leak inspection method, it is possible to inspect the hermeticity of the housing purely without requiring the electrical output of the sensor, so it is suitable for an acceleration sensor or the like in which acquisition of the electrical output is not easy. .

  However, in the bubble leak inspection method, there is a problem that it is necessary to visually check the bubbles, and it is difficult to automate the inspection and incorporate it into the production line. Further, if a plurality of sensors are inspected at the same time, it becomes unclear from which sensor the bubbles are generated, so that there is a problem that the inspection must be performed one by one.

  The present invention has been made to solve such a problem, and it is possible to perform a leak inspection apparatus for an electronic component and an electronic component capable of performing a leak inspection of an electronic component such as an acceleration sensor at high speed and low cost. A leak inspection method is to be provided.

(1) The present invention is an electronic component leak inspection apparatus that outputs a predetermined electrical signal by biasing an inertial body inside a housing, and the electronic component includes a variable component having a predetermined frequency. a power supply for applying a voltage, and a detector for detecting an output of the electronic component, the evaluation device compared to determine the tightness of the electronic component and the reference value an output value obtained by the detection device, wherein A sealing device that houses electronic components in a sealed state, a pressure change device that changes the pressure in the sealing device, and a plurality of the electronic components, and an electronic component holding that is housed in the sealing device together with the electronic components comprising apparatus and, wherein the detection device has a contact portion to be electrically connected to all of the electronic components on the electronic component holding device within the sealed device, further, the detection device, The electrical joint condition in serial contact portion, characterized in that it comprises a switching control unit for switching to the respective electronic component, an electronic component leakage inspection apparatus.

  (2) The present invention is also the electronic component leakage inspection apparatus according to (1), characterized in that the frequency of the fluctuation component of the operating voltage is set based on the resonance frequency of the electronic component. .

(3) In the present invention, the pressure change device controls the inside of the sealing device to at least a first internal pressure and a second internal pressure, and the detection device outputs the first electronic component output under the first internal pressure. One output and a second output of the electronic component output under the second internal pressure are detected, and the evaluation device determines pass / fail of the airtightness of the electronic component based on a difference between the first output and the second output. The electronic component leakage inspection apparatus according to (1) or (2) .

(4) The present invention is also characterized in that the first internal pressure is atmospheric pressure and the second internal pressure is lower than the atmospheric pressure, wherein the electronic component leak inspection apparatus according to (3) It is.

(5) The present invention is also characterized in that the pressure changing device includes a vacuum pump, and exhausts the gas in the sealing device to bring the internal pressure into a low pressure state. (1) to (4) It is the leak inspection apparatus for electronic components in any one .

(6) In the electronic component leakage inspection apparatus according to any one of (1) to (7) , the electronic component may be an acceleration sensor, a gyro sensor, or a crystal resonator. is there.

(7) The present invention also applies an operating voltage including a fluctuating component to an electronic component that outputs a predetermined electrical signal by biasing an inertial body inside the housing, and accommodates the electronic component in a sealing device. In addition, the pressure in the sealing device is changed, a plurality of the electronic components are held by the electronic component holding device in the sealing device, and all the electronic components on the electronic component holding device are electrically connected by the contact portion. The electrical connection state in the contact portion is switched for each electronic component, the output of the electronic component is detected, and the output fluctuation of the electronic component before and after the internal pressure change in the sealing device, An electronic component leak inspection method, comprising: determining airtightness of the electronic component.

  According to the leak inspection apparatus for electronic components or the leak inspection method for electronic components according to the present invention, it is possible to obtain an excellent effect that leak inspection of electronic components such as an acceleration sensor can be performed at high speed and at low cost.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram of an electronic component leak inspection apparatus 100 according to the first embodiment.

  As shown in the figure, an electronic component leak inspection apparatus 100 includes a sealing device 110, a pressure changing device 120 that changes the pressure inside the sealing device 110, and an electronic component 200 such as an acceleration sensor that is a target for leak inspection. It comprises a detection device 130 that measures an output signal, a power supply device 140 that applies an operating voltage to the electronic component 200, and an evaluation device 160.

  The sealing device 110 is a hollow box-shaped container made of resin or metal. The sealing device 110 is formed so as to keep the pressure inside the container constant (sealed state).

  In the present embodiment, the electronic component 200 is accommodated in the sealing device 110 while being placed on the electronic component holding device 300. The electronic component holding device 300 is used for transporting the electronic component 200 in the production line of the electronic component 200, and holds and transports the plurality of electronic components 200 arranged in a matrix. In other words, the present embodiment is configured such that a leak inspection can be performed at a time while a plurality of electronic components 200 are placed on the electronic component holding device 300.

  The pressure changing device 120 includes a pipe 122 connected to the sealing device 110 and bifurcated, a vacuum pump connection valve 124 and a vacuum pump 126 connected to one end of the pipe 122, and the other end of the pipe 122 branched. And an atmospheric release valve 128 connected to the.

  The pressure changing device 120 lowers the pressure in the sealing device 110 to a vacuum by opening the vacuum pump connection valve 124 and connecting the vacuum pump 126 to the sealing device 110 to exhaust the gas in the sealing device 110. Moreover, the pressure in the sealing device 110 is raised to atmospheric pressure by opening the air release valve 128 to open the air in the sealing device 110 to the atmosphere. That is, the pressure changing device 120 can set the pressure in the sealing device 110 to an arbitrary pressure from atmospheric pressure to vacuum.

  The detection device 130 includes a contact portion 132 that is electrically joined to the electronic component 200, a multiplexer 134 that is electrically connected to the contact portion 132, and an output signal measuring device 136 that is electrically connected to the multiplexer 134. .

  The contact portion 132 includes a plurality of probes 132 a and is configured to be joined simultaneously with all the electronic components 200 placed on the electronic component holding device 300. The multiplexer 134 switches the signals transmitted from the plurality of electronic components 200 and transmits them to the output signal measuring device 136. The output signal measuring device 136 measures a signal output from the electronic component 200.

  The power supply device 140 includes a DC power supply 142 that generates a DC voltage and an AC power supply 144 that generates an AC voltage. By combining these, the power supply device 140 includes a fluctuation component having a predetermined frequency in the vicinity of a certain voltage. A power supply voltage can be generated. Further, the power supply device 140 is connected to the detection device 130 by the cable 146 and is electrically joined to the electronic component 200.

  The evaluation device 160 is electrically connected to the output signal measuring device 136 of the detection device 130 and receives the output value of the electronic component 200. Further, the evaluation device 160 compares the output value received from the electronic component 200 with a reference value of a predetermined output (here, the output value of the electronic component 200 when the atmosphere around the electronic component 200 is changed). The pass / fail of the airtightness of the electronic component 200 is determined. Note that an ideal output value for the ambient pressure of the electronic component 200 may be adopted as the reference value of the output of the electronic component 200.

  Next, the principle of generating an output signal due to vibration of the electronic component 200 will be described. FIG. 2 is a circuit diagram of the electronic component 200 and the power supply device 140, and FIG. 3 is a structural diagram of the sensor unit 210.

  The electronic component 200 includes, for example, a sensor unit 210 such as a piezoresistive acceleration sensor that generates an output signal by biasing an inertial body in the housing due to movement or vibration, and an amplification circuit 220 that amplifies the output signal by a predetermined magnification. Consists of

  As shown in FIG. 3, in the sensor unit 210, a sensor element 202 is accommodated in a hermetically sealed casing 201. An inert gas or the like is sealed inside the casing 201. The sensor element 202 includes a rectangular frame-shaped support portion 203, a beam 204 protruding inward from the upper end of the support portion 203, and a weight (inertial body) 205 supported by the beam 204. A plurality of piezoresistive elements 206 are disposed on the beam 204.

  When acceleration is applied to the sensor unit 210, the weight 205 moves (bias) and deforms the beam 204. Then, stress is generated in the piezoresistive element 206, and the resistance of the piezoresistive element 206 changes. The electronic component 200 converts the change in resistance of the piezoresistive element 206 into a change in voltage by a Wheatstone bridge (not shown) and outputs the change.

  Returning to FIG. 2, the amplifier circuit 220 is specifically an operational amplifier circuit such as an operational amplifier or a transistor, but in this embodiment, two input terminals 222 for inputting an output signal from the sensor unit 210, and an amplifier The operational amplifier includes an output terminal 224 for outputting a later signal and two power supply terminals 226 for inputting a power supply voltage of the amplifier circuit 220. The input terminal 222 includes two input terminals, an inverting input terminal Vin− and a non-inverting input terminal Vin +. The amplifier circuit 220 outputs from the output terminal 224 a value obtained by multiplying the difference between the signals input to the inverting input terminal Vin− and the non-inverting input terminal Vin + by the amplification factor A of the amplifier circuit 220.

  The power supply device 140 includes a DC power supply 142 that generates a DC voltage and an AC power supply 144 that generates an AC voltage in a serial connection state. The DC power supply voltage including a predetermined fluctuation component as shown in FIG. Generate. Note that the DC power supply 142 and the AC power supply 144 may be connected in parallel as long as they can generate a voltage including a DC component and an AC component. Although the case where the DC power supply 142 and the AC power supply 144 are combined to generate the applied voltage including the fluctuation component is shown here, the present invention is not limited to this, and can be generated by other methods.

  Referring back to FIG. 2, generally, when a predetermined DC voltage is applied to the power supply terminal 226, the amplifier circuit 220 such as an operational amplifier has a difference between the input signals Vin− and Vin + as shown in the following equation 1, A value obtained by multiplying the amplification factor A is output.

  Vout = A (Vin + −Vin−) (Formula 1)

  When a power supply voltage including a fluctuation (noise) component is input to the electronic component 200, the output is affected to some extent by the fluctuation of the power supply voltage. The change (influence) of the output with respect to the fluctuation of the power supply voltage expressed as a ratio is called a power supply voltage rejection ratio (Power Supply Rejection Ratio). The power supply voltage fluctuation rejection ratio is a characteristic inherent to the amplifier circuit 220 such as an operational amplifier, and is generally expressed in dB. Further, the power supply voltage fluctuation removal ratio is less affected by fluctuations in the power supply voltage as the value is larger.

  That is, the electronic component 200 has a property that, when a power supply voltage including a predetermined fluctuation (noise) component is applied, a leakage voltage flows into the sensor unit 210 to some extent based on the power supply voltage fluctuation removal ratio. . Therefore, in this embodiment, a power supply voltage including a predetermined fluctuation component is applied to the electronic component 200 using this property, so that a part of the fluctuation component leaks to the inverting input terminal Vin− or the non-inverting input terminal Vin + side. Let As a result, a fluctuation component is applied to the piezoresistive element 206 side, the weight 205 is vibrated, and a signal including this vibration is output from the sensor unit 210. As a result, the amplifier circuit 220 amplifies the signal including the vibration of the weight 205 due to the leakage voltage and outputs it from the output terminal 224. Therefore, the electronic component 200 is forced to vibrate by using the voltage of the AC power supply 144. A leak inspection is performed using this vibration.

  Next, a procedure of leak inspection by the electronic component leak inspection apparatus 100 of the present embodiment will be described.

  First, the electronic component holding device 300 on which the electronic component 200 is placed is accommodated in the sealing device 110, and a power supply voltage including a fluctuation component of a predetermined amplitude and frequency is applied to the electronic component 200 by the power supply device 140. Then, the pressure in the sealing device 110 is maintained at the first internal pressure (for example, atmospheric pressure) by the pressure changing device 120, and the signal output from each electronic component 200 under the first internal pressure is measured by the output signal measuring device 136. Store as output. Next, the vacuum pump 126 is operated to change the pressure in the sealing device 110 to the second internal pressure (for example, substantially vacuum), and the signal output from each electronic component 200 under the second internal pressure is output by the output signal measuring device 136. Measure and store as second output. Finally, the first output and the second output are compared for each electronic component 200 to determine whether the airtightness of each electronic component 200 is acceptable.

  When a power supply voltage including a fluctuation component is applied to the electronic component 200, the sensor unit 210 vibrates due to the leakage voltage, and an output signal including the vibration component is obtained. In addition, the vibration state of the sensor unit 210 varies depending on the atmospheric pressure, humidity, and temperature of the gas inside the housing 201. That is, in this embodiment, when the airtightness of the housing 201 that houses the electronic component 200 is low, the output varies between the atmospheric pressure state and the substantially vacuum state. That is, the first output and the second output have different values. Therefore, the evaluation device 160 compares the first output and the second output to determine a leak product.

  On the other hand, if the housing 201 of the electronic component 200 is properly hermetically sealed, the inside of the housing 201 is maintained at a constant pressure regardless of the pressure change inside the sealing device 110, so the first output and the second output are The values are almost equal. Therefore, the evaluation device 160 compares the first output with the second output and determines that the product is a passing product.

  As described above, in the electronic component leak inspection apparatus 100 according to the present embodiment, a voltage that is changed using the AC power supply 144 is applied to the electronic component 200, and the voltage that leaks from the applied voltage to the sensor unit 210 side. Thus, the airtightness of the electronic component 200 is determined by electrically vibrating the sensor unit 210 and measuring the output signal. As a result, the leak inspection of the electronic component 200 can be performed in a short time with an extremely inexpensive configuration.

  In addition, a large number of electronic components can be reliably inspected at a time, which has the effect of reducing costs and reducing the size of the apparatus.

  In addition, if the frequency of the fluctuation component of the power supply device 140 is made equal to the resonance frequency of the electronic component 200, it is possible to create a situation in which the sensor unit 210 is more likely to vibrate, and the output increases and the leak inspection is performed efficiently. Can do.

  Moreover, there is an effect that the leak inspection can be performed efficiently by setting the frequency and amplitude of the fluctuation component of the power supply voltage depending on the type of the electronic component 200.

  Further, since the first output under the first internal pressure and the second output under the second internal pressure are compared for each of the plurality of electronic components 200, each electronic component 200 is not affected by variations in sensitivity of each electronic component 200. The component 200 can be inspected for leaks.

  In addition, by setting the first internal pressure on the high pressure side to atmospheric pressure, no pressure is required in the sealing device 110, and the pressure changing device 120 can be made inexpensive.

  Moreover, since the pressure changing device 120 includes the vacuum pump 126, the pressure in the sealing device 110 can be changed in a short time, and the inspection time can be shortened.

  Further, since the electronic component 200 is accommodated in the sealing device 110 while being placed on the electronic component holding device 300, the electronic component leak inspection device 100 can be electronically operated without requiring an expensive and complicated handling device. It can be incorporated into the production line of the component 200. Thereby, the manufacturing efficiency of the electronic component 200 can be improved as a whole including the leak inspection process.

  Further, since the detection device 130 includes the contact portion 132 that is electrically joined to all the electronic components 200 on the electronic component holding device 300, the detection device 130 is connected to all the electronic components 200 on the electronic component holding device 300 at a time. The inspection time can be shortened.

  In addition, since the detection device 130 includes the multiplexer 134, it is possible to measure the output signal for each electronic component 200 and perform a leak test individually while joining all the electronic components 200 at one time with the contact portion 132. it can. It is also preferable to connect a plurality of multiplexers 134 and output signal measuring devices 136 in parallel to the contact portion 132. By doing in this way, since the output signals of the plurality of electronic components 200 can be measured in parallel, the inspection time can be further shortened.

  The leak inspection apparatus for electronic parts and the leak inspection method for electronic parts of the first embodiment can be used for daily inspection of acceleration sensors of airbag apparatuses such as automobiles and motorcycles.

  For example, FIG. 5 is a schematic structural diagram of an airbag apparatus 600 using the electronic component leakage inspection apparatus 400 according to the second embodiment of the present invention.

  The electronic component leak inspection apparatus 400 includes an electronic component 500 and a power supply device 540. The electronic component 500 includes a sensor unit 510 such as a piezoresistive acceleration sensor and an amplification circuit 520 that amplifies the output signal by a predetermined magnification, and is sealed with a housing (not shown). The power supply device 540 includes a DC power supply 542 that generates a DC voltage and an AC power supply 544 that generates a fluctuating voltage. Since the electronic component 500 and the power supply device 540 have substantially the same configuration and function as the electronic component 200 and the power supply device 140 described in the first embodiment, detailed description is omitted by matching the last two digits of the reference numerals. .

  The sensor unit 510 is electrically connected to the airbag device 600, and is configured to output a signal to the airbag device 600 when the sensor unit 510 receives an impact due to an automobile collision or the like.

  The airbag apparatus 600 includes an airbag 610 and an airbag control apparatus 620, and determines whether or not to open the airbag (open the airbag) based on a signal from the electronic component 500.

  The power supply device 540 is provided so as to operate in conjunction with the engine key of the automobile. When the engine is started, the power supply device 540 temporarily supplies a DC voltage including a fluctuation component to the electronic component 500 when the engine is started. The leak inspection of the component 500 is executed. It is also possible to inspect when the engine is not running.

  The electronic component 500 electrically vibrates the sensor unit 510 according to the leakage voltage of the fluctuation component of the power supply voltage, and amplifies the vibration result according to the amplification factor of the amplification circuit 520 and outputs the amplified result.

  The detection device and the evaluation device are housed in the airbag control device 620, detect the output of the amplifier circuit 520, compare the detection value with the detection value (reference value) at the time of shipment of the vehicle, and whether there is any fluctuation Judging. Specifically, if there is no change between the detected value and the initial value (or within a predetermined range), it is determined that the airtightness of the electronic component 500 is maintained, and the fluctuation is equal to or greater than a predetermined threshold. It is determined that the electronic component 500 is leaking.

  The electronic component leak inspection apparatus 400 determines and prevents the possibility of malfunction of the airbag apparatus 600 due to poor airtightness of the electronic component 500 before the automobile starts to move.

  Further, the electronic component leak inspection apparatus 400 supplies a power supply voltage including a fluctuation component to the electronic component 500 at a predetermined interval even when the engine key is not operated (the automobile is not moving). There is an effect that 500 airtightness inspections can be automatically performed. In particular, the electronic component leak inspection apparatus 400 can be used for a long period of time during use of an automobile even when the airtightness of the electronic component 500 is gradually lost due to deterioration over time or fine leaks. It is possible to inspect over the whole area.

  The leak inspection apparatus for electronic parts and the leak inspection method for electronic parts of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Of course.

  For example, the electronic component 200 and the electronic component 500 to be subjected to a leak inspection are not limited to the sensors having the structure shown in the above embodiment, and a predetermined electrical signal is generated by the bias of the internal inertial body. Other electronic structures may be used as long as they are output electronic parts.

  Further, the actions and effects described in the embodiments of the present invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to what was done.

  The leak inspection apparatus for electronic parts and the leak inspection method for electronic parts according to the present invention can be used in the field of manufacture, inspection or calibration of acceleration sensors and the like.

1 is a schematic configuration diagram of an electronic component leak test apparatus 100 according to a first embodiment of the present invention. It is a circuit diagram of the electronic component 200 and the power supply device 140 in the leak test apparatus for the electronic component. It is sectional drawing of an example of the sensor part 210 used as the object of a leak test | inspection. 3 is a schematic diagram of an input power supply waveform to the electronic component 200. FIG. It is a schematic block diagram of the leak test apparatus 400 for electronic components in 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,400 ... Electronic component leak test | inspection apparatus 110 ... Sealing device 120 ... Pressure change device 126 ... Vacuum pump 130 ... Detection apparatus 132 ... Contact part 134 ... Multiplexer 140, 540 ... Power supply device 142,542 ... DC power supply 144,544 ... AC power supply 160 ... Evaluation device 200,500 ... Electronic component 300 ... Electronic component holding device 600 ... Airbag device

Claims (7)

An electronic component leak inspection apparatus that outputs a predetermined electrical signal by biasing an inertial body inside the housing,
A power supply device for applying an operating voltage including a fluctuation component having a predetermined frequency to the electronic component;
A detection device for detecting an output of the electronic component;
An evaluation device that determines an airtightness of the electronic component by comparing an output value obtained by the detection device with a reference value;
A sealing device for containing the electronic component in a sealed state;
A pressure changing device for changing the pressure in the sealing device;
A plurality of electronic components, and an electronic component holding device accommodated in the sealing device together with the electronic components ;
Equipped with a,
The detection device has a contact portion that is electrically joined to all the electronic components on the electronic component holding device in the sealing device, and
The detection device includes a switching control unit that switches an electrical connection state in the contact unit for each electronic component.
Leak inspection device for electronic parts. Based on the resonance frequency of the electronic component, the frequency of the fluctuation component of the operating voltage is set,
The leak inspection apparatus for electronic components according to claim 1. The pressure changing device controls the inside of the sealing device to at least a first internal pressure and a second internal pressure,
The detection device detects a first output of the electronic component output under the first internal pressure and a second output of the electronic component output under the second internal pressure;
The evaluation apparatus is characterized by determining pass / fail of the airtightness of the electronic component based on a difference between the first output and the second output.
The leak inspection apparatus for electronic parts according to claim 1 or 2 . The first internal pressure is atmospheric pressure, and the second internal pressure is lower than the atmospheric pressure,
The leak inspection apparatus for electronic components according to claim 3 . The pressure changing device includes a vacuum pump, and exhausts the gas in the sealing device to bring the internal pressure to a low pressure state.
The leak inspection apparatus for electronic components according to any one of claims 1 to 4 . The electronic component is an acceleration sensor, a gyro sensor, or a crystal resonator,
The leak inspection apparatus for electronic components according to any one of claims 1 to 7 . Applying an operating voltage containing a fluctuation component to an electronic component that outputs a predetermined electrical signal by biasing the inertial body inside the housing,
While accommodating the electronic component in a sealing device, changing the pressure in the sealing device,
A plurality of the electronic components are held by the electronic component holding device in the sealing device ,
Electrically joined to all the electronic components on the electronic component holding device by contact parts,
The electrical connection state in the contact part is switched for each electronic component, and the output of the electronic component is detected,
A leak inspection method for an electronic component , wherein airtightness of the electronic component is determined based on output fluctuation of the electronic component before and after a change in internal pressure in the sealing device .

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