Test apparatus and test method

Abstract

Provided is a test apparatus comprising: a first power source that outputs a first voltage of a predetermined magnitude or a first current of a predetermined magnitude; a first switch unit that connects, to the first power source, a connection terminal of a device under test to be tested among connection terminals of a plurality of devices under test; a first measurement unit that measures electrical characteristics of the device under test to be tested in response to the first power source being connected to the device under test to be tested; and a second voltage source that outputs a second voltage of a predetermined magnitude with respect to the connection terminal of at least one device under test, which is different from the device under test to be tested among the plurality of devices under test.

Description

Testing equipment and testing method

[0001] The present invention relates to a testing device and a testing method.

[0002] Patent Documents 1 and 2 state, "In this embodiment, a measuring means (SMU 20) that measures a certain electrical characteristic of the DUT 50, another measuring means (LCR meter 22 or pulse generator 24) that measures another electrical characteristic of the DUT, and a switching unit 12 (ASU 12P, 12M) that is connected to a control means (controller 202) and has a minute current detection means are used. The switching unit is electrically connected to the DUT 50. The switching unit 12 is also electrically connected to several measuring means by cables, and switches whether the device under test is electrically connected to one of the measuring means or the second measuring means based on a control signal from the control means (controller 202)..." (paragraph 0035). [Prior Art Documents] [Patent Documents] [Patent Document 1] JP 2005-300495 A [Patent Document 2] JP 2010-190768 A General disclosure

[0003] In a first aspect of the present invention, there is provided a test apparatus comprising: a first power supply that outputs a first voltage of a predetermined magnitude or a first current of a predetermined magnitude; a first switch section that connects a connection terminal of a device under test to be tested among a plurality of connection terminals of devices under test to the first power supply; a first measurement section that measures electrical characteristics of the device under test to be tested in response to the first power supply being connected to the device under test; and a second voltage source that outputs a second voltage of a predetermined magnitude to the connection terminal of at least one other device under test that is different from the device under test to be tested among the plurality of devices under test.

[0004] In the above test apparatus, the current path between the second voltage source and the at least one other device under test and the current path between the first power source and the device under test being tested may be separate paths.

[0005] In any of the above test devices, the second voltage source may output a voltage in parallel with measurement by the first measuring section.

[0006] Any of the above test apparatuses may further include a second switch section that selectively connects the second voltage source to each of the connection terminals of the at least one other device under test.

[0007] In the above test apparatus, the at least one other device under test may include, among the plurality of devices under test, a device under test that is to be measured by the first measuring section next to the device under test to be tested.

[0008] Any of the above test apparatuses having the second switch unit may further include a second measurement unit that measures a value corresponding to the voltage generated in the device under test as a result of a predetermined magnitude of current being passed through the device under test at a timing different from the measurement timing by the first measurement unit, the second measurement unit being connected between the second voltage source and the second switch unit, and the second switch unit connecting the second measurement unit to the device under test as a result of the second measurement unit performing measurement.

[0009] Any of the above test apparatuses may further include a plurality of resistors provided on the wiring lines connecting the second voltage source to each of the connection terminals of the plurality of devices under test.

[0010] In the above-mentioned test apparatus, the first measuring section may adjust the measurement value when the first switch section connects the device under test to the first power supply, in accordance with the measurement value when the first switch section does not connect the device under test to the first power supply.

[0011] In any of the above test devices, the first power supply may output a predetermined first voltage, and the second voltage source may be an amplifier that amplifies the first voltage output from the first power supply by a predetermined gain.

[0012] In any of the above test devices, the first power supply may output a predetermined first voltage, and the second voltage may be a voltage having the same magnitude as the first voltage.

[0013] In any of the above test apparatuses, the first power supply may output a predetermined first voltage, and the second voltage may be closer to the first voltage than a ground voltage of the plurality of devices under test.

[0014] In any of the above test apparatuses, the current that the second voltage source supplies to the at least one other device under test may be larger than the current that the first power source supplies to the device under test that is the test target.

[0015] Any of the above test apparatuses may further include a judgment section that judges whether the device under test to be tested is good or bad based on the measurement results by the first measurement section, and the judgment section may judge the device under test to be bad if the rate of change in the value of the measurement results by the first measurement section does not become equal to or less than a reference value within a reference time after connection from the first power supply to the device under test to be tested.

[0016] In any of the above test apparatuses, the first measuring section may measure a value corresponding to the current flowing in the device under test as the first voltage is applied from the first power supply, or may measure a value corresponding to the voltage generated in the device under test as the first current is flowing from the first power supply.

[0017] In a second aspect of the present invention, there is provided a testing method comprising the steps of connecting a connection terminal of a device under test to be tested among connection terminals of a plurality of devices under test to a first power supply that outputs a first voltage of a predetermined magnitude or a first current of a predetermined magnitude, and applying a second voltage of a predetermined magnitude from a second voltage source to the connection terminal of at least one other device under test among the plurality of devices under test that is different from the device under test to be tested, and measuring electrical characteristics of the device under test to be tested in response to the first power supply being connected to the device under test to be tested.

[0018] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also constitute inventions.

[0019] 22 shows a test system 1 according to a first embodiment; FIG. 23 shows the operation of a test device 2; FIG. 24 shows operational waveforms of the test device 2; FIG. 25 shows a test system 1A according to a second embodiment; FIG. 26 shows operational waveforms of the test device 2A; and FIG. 27 shows an example of a computer 2200 in which aspects of the present invention may be embodied in whole or in part.

[0020] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention as claimed. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0021] 1 shows a test system 1 according to this embodiment. The test system 1 includes a plurality of devices under test 10 and a test apparatus 2. In the figure, the devices under test 10 are referred to as DUTs (Device Under Test).

[0022] (Device Under Test 10) Each device under test 10 is an electronic device to be tested by the test apparatus 2. Each device under test 10 may be, for example, an integrated circuit including a semiconductor, a discrete semiconductor element, or another type of device.

[0023] Each device under test 10 may have at least one connection terminal 101 connected to the test apparatus 2. Each device under test 10 may further have another connection terminal (not shown) connected to a ground voltage.

[0024] (Test Apparatus 2) The test apparatus 2 tests each device under test 10. The test apparatus 2 may test the pass / fail of the electrical static characteristics of each device under test 10 that has been connected in advance. The test apparatus 2 may sequentially switch between a number of devices under test 10 (in this embodiment, for example, n devices under test 10 (where n is a natural number of 2 or more)) as the test target and test one of the devices under test 10. The order of the devices under test 10 may be set according to their connection positions relative to the test apparatus 2. When n devices under test 10 are connected to the test apparatus 2 in a line, the device under test 10 at one end may be the first device under test 10, and the device under test 10 at the other end may be the nth device under test 10.

[0025] The test device 2 has a constant voltage generating current measuring unit 20, a first switch unit 21, a second voltage source 23, a second switch unit 24, a constant current generating voltage measuring unit 25, a third switch unit 26, a judgment unit 27, and a test controller 28.

[0026] ((Constant voltage generating current measuring section 20)) The constant voltage generating current measuring section 20 measures a value corresponding to a current flowing through the device under test 10 in response to application of a constant voltage to the device under test 10. The constant voltage generating current measuring section 20 has a first voltage source 201, an amplifier 202, and a current sensor 203.

[0027] (((First voltage source 201))) The first voltage source 201 is an example of a first power supply, and outputs a first voltage of a predetermined magnitude. The first voltage source 201 may supply the first voltage to the non-inverting input terminal of the amplifier 202. The first voltage may be a voltage for passing a current through the device under test 10 to be tested and performing a measurement, that is, a measurement voltage. The magnitude of the first voltage may be set arbitrarily depending on the characteristics of the device under test 10. In this figure, the first voltage source 201 is illustrated as a battery as an example, but it may also be another device such as a rectifier or a converter.

[0028] (((Amplifier 202))) Amplifier 202 is provided between first voltage source 201 and current sensor 203 to form a voltage follower circuit. The output terminal of amplifier 202 is connected to current sensor 203, and is also connected to the inverting input terminal via current sensor 203. The gain of amplifier 202 may be 1 (0 dB), and the first voltage output from first voltage source 201 may be output from the output terminal.

[0029] (((Current Sensor 203))) The current sensor 203 is provided between the output terminal of the amplifier 202 and the first switch section 21. The current sensor 203 is an example of a first measurement section, and measures electrical characteristics of the device under test 10 in response to the first voltage source 201 being connected to the device under test 10. The current sensor 203 may measure a value corresponding to a current flowing through the device under test 10 in response to the application of a first voltage from the first voltage source 201. In the present embodiment, as an example, the current sensor 203 measures the current itself flowing between the output terminal of the amplifier 202 and the first switch section 21. However, the current sensor 203 may measure at another position, or may measure another value corresponding to the current (for example, a voltage generated across a resistor in response to the current). The current sensor 203 may supply the measurement value to the determination section 27.

[0030] ((First Switch Section 21)) The first switch section 21 is provided between the constant voltage generating current measuring section 20 and the n devices under test 10. The first switch section 21 connects the connection terminal 101 of the device under test 10 to be tested, among the connection terminals 101 of the n devices under test 10, to the first voltage source 201. The first switch section 21 may alternatively connect the connection terminal 101 of the device under test 10 to the first voltage source 201. The first switch section 21 may have n switches 210, each having one end connected to the output terminal of the amplifier 202 in the constant voltage generating current measuring section 20 and the other end connected to each of the connection terminals 101 of the n devices under test 10. Of the n switches 210, the other end of the Nth switch 210 (where N is a natural number satisfying 1≦N≦n) may be connected to the connection terminal 101 of the Nth device under test 10. Each switch 210 may be controlled by a test controller 28, which will be described later.

[0031] ((Second voltage source 23)) The second voltage source 23 outputs a second voltage of a predetermined magnitude. The second voltage source 23 may output the second voltage of a predetermined magnitude to the connection terminal 101 of at least one other device under test 10 than the device under test 10 to be tested among the n devices under test 10. The second voltage source 23 according to this embodiment may work in cooperation with the second switch section 24 to output the second voltage to at least one device under test 10 that is not the test target.

[0032] The device under test 10 from which the second voltage is output may include, among the n devices under test 10, a device under test 10 that is measured by the current sensor 203 next to the device under test 10 to be tested, or may include a device under test 10 that is measured before the device under test 10 to be tested, or may include a device under test 10 that is placed near the device under test 10 to be tested. As an example in the present embodiment, the device under test 10 from which the second voltage is output may be each of n-1 devices under test 10 different from the device under test 10 to be tested, among the n devices under test 10.

[0033] Second voltage source 23 may output the second voltage in parallel with measurement by current sensor 203, and may output a voltage over the measurement period by current sensor 203. Second voltage source 23 may be an amplifier that amplifies the first voltage output from first voltage source 201 by a preset gain, and may output a voltage in parallel with the voltage output by first voltage source 201. Although the illustration is simplified in FIG. 1 , the amplifier serving as second voltage source 23 may be connected to amplifier 202 of constant voltage generating current measuring unit 20 to form a voltage follower circuit, and may have a gain of 1 (0 dB).

[0034] The second voltage may be a voltage for causing a current to flow through a device under test 10 other than the test target, to settle the device under test 10 to a standby potential, i.e., a standby voltage. The second voltage may be a voltage closer to the first voltage than the ground voltages of the n devices under test 10, and in this embodiment, for example, may be a voltage having the same magnitude as the first voltage.

[0035] The current path flowing in the test apparatus 2 due to the voltage from the second voltage source 23 may be insulated from the current path flowing in the test apparatus 2 due to the voltage from the first voltage source 201. In the present embodiment, as an example, the second voltage source 23 is an amplifier, and therefore the input side and the output side are insulated. Furthermore, the current path between the second voltage source 23 and each device under test 10 that is not the test target, and the current path between the first voltage source 201 and the device under test 10 that is the test target, are separate paths that have no common parts and are insulated from each other.

[0036] ((Second switch section 24)) The second switch section 24 is provided between the second voltage source 23 and the n devices under test 10. When the constant voltage generating current measuring section 20 performs measurement, the second switch section 24 selectively connects the second voltage source 23 to each of the connection terminals 101 of the devices under test 10 other than those being tested by the constant voltage generating current measuring section 20. As an example in the present embodiment, the second switch section 24 may connect the connection terminals 101 of each of the n-1 devices under test 10 that are not being tested to the second voltage source.

[0037] When the constant current generating voltage measuring section 25 (described later) performs measurement, the second switch section 24 may connect the constant current generating voltage measuring section 25 to the connection terminal 101 of the device under test 10 that is the test target by the constant current generating voltage measuring section 25. When the constant current generating voltage measuring section 25 performs measurement, the second switch section 24 may alternatively connect the device under test 10 that is the test target to the constant current generating voltage measuring section 25.

[0038] The second switch section 24 may have n switches 240, each having one end connected to the second voltage source 23 and the other end connected to the connection terminals 101 of the n devices under test 10. Of the n switches 240, the other end of the Nth switch 240 may be connected to the connection terminal 101 of the Nth device under test 10. Each switch 240 may be controlled by the test controller 28.

[0039] The wiring from the Nth switch 240 in the second switch section 24 to the Nth device under test 10 and the wiring from the Nth switch 210 in the first switch section 21 to the Nth device under test 10 may have a common wiring portion. A noise removal filter such as a smoothing capacitor may be provided in the common wiring portion. Furthermore, a board-like interface for connecting the test apparatus 2 and each device under test 10 may be provided between the n devices under test 10 and the n switches 210 and 240.

[0040] (Constant Current Generation Voltage Measuring Section 25) The constant current generation voltage measuring section 25 is an example of a second measuring section, and is connected between the second voltage source 23 and the second switch section 24. The constant current generation voltage measuring section 25 measures a value corresponding to a voltage generated in the device under test 10 in response to a current of a predetermined magnitude being passed through the device under test 10. The constant current generation voltage measuring section 25 may perform measurements at timings different from the timings of measurements by the current sensor 203, and may perform measurements while the device under test 10 to be tested by the constant current generation voltage measuring section 25 and the constant current generation voltage measuring section 25 are connected via the second switch section 24. The predetermined magnitude of current may be set arbitrarily depending on the characteristics of the device under test 10. The constant current generation voltage measuring section 25 may include a current source (not shown) that passes a constant current through the device under test 10 via the second switch section 24. The constant current generating voltage measuring section 25 may include a sensor (a voltage sensor, for example) not shown that measures a value corresponding to the voltage generated in the device under test 10 under test in response to the current from the current source and supplies the value to the judging section 27. Note that the constant current generating voltage measuring section 25 may measure not the voltage itself generated in the device under test 10 under test, but another value corresponding to the voltage (for example, a current flowing in response to the voltage).

[0041] ((Third Switch Unit 26)) Third switch unit 26 is provided between second voltage source 23 / constant current generation voltage measurement unit 25 and second switch unit 24. Third switch unit 26 has switch 261 provided between constant current generation voltage measurement unit 25 and second switch unit 24, and switch 262 provided between second voltage source 23 and second switch unit 24. Switch 261 may be turned on when constant voltage generation current measurement unit 20 performs measurement, that is, when current sensor 203 performs measurement, and switch 262 may be turned on when constant current generation voltage measurement unit 25 performs measurement.

[0042] ((Judging Section 27)) The judging section 27 judges the pass / fail of the device under test 10 to be tested based on the measurement results by the constant voltage generating current measuring section 20. The judging section 27 according to this embodiment may judge the pass / fail of the device under test 10 to be tested based on the measurement results by the constant voltage generating current measuring section 20 and the constant current generating voltage measuring section 25. As an example, the judging section 27 may judge the device under test 10 to be pass / fail if the device under test 10 to be tested is judged to be normal based on the measurement results by the constant voltage generating current measuring section 20 and the device under test 10 to be normal based on the measurement results by the constant current generating voltage measuring section 25, and may judge the device under test 10 to be fail in other cases. Note that the judging section 27 may judge the pass / fail of the device under test 10 based only on the measurement results by the constant voltage generating current measuring section 20.

[0043] (Test Controller 28) The test controller 28 controls each section of the test apparatus 2 to execute a test on each device under test 10. For example, the test controller 28 may cause the first voltage source 201 and the second voltage source 23 to output a voltage, and switch the connection state between the first voltage source 201 and the second voltage source 23 and the device under test 10 using the first switch section 21 and the second switch section 24, so that the current flowing through the device under test 10 being tested is measured by the current sensor 203. The test controller 28 may cause the constant current generation voltage measurement section 25 to output a current, and switch the connection state between the constant current generation voltage measurement section 25 and the device under test 10 using the second switch section 24, so that the constant current generation voltage measurement section 25 measures the voltage generated in the device under test 10 being tested. The test controller 28 may be realized by software being executed by a processor or the like.

[0044] (Effects Obtained by the Test Apparatus 2) According to the test apparatus 2 described above, the second voltage is output to the connection terminal 101 of the device under test 10 other than the test target, so that the device under test 10 other than the test target can be settled to a predetermined potential and placed in a standby state for testing. For example, when a test is performed by applying the first voltage to a defective device under test 10, charge may move through capacitance between the wiring from the first switch section 21 to the device under test 10 to be tested and the wiring from the first switch section 21 to a device under test 10 that is not the test target. Even in such a case, the output of the second voltage eliminates the charge movement in advance, lowering the impedance of the wiring to the device under test 10 other than the test target, making it less susceptible to the effects of external disturbances and coupling between the wiring, and placing the device under test 10 other than the test target in a standby state for testing. Furthermore, even if the device under test 10 is a capacitive load and needs to be charged in order to perform a test, the charge can be charged in advance by outputting the second voltage, and a device under test 10 other than the test target can be put into a standby state for the test. Therefore, the start of testing for each device under test 10 can be accelerated.

[0045] Furthermore, since the current path from the second voltage source 23 to the device under test 10 other than the test target and the current path from the first voltage source 201 to the device under test 10 are separate paths, even when measuring a value corresponding to a minute current in the current sensor 203, a non-minute current can be passed through the current path from the second voltage source 23 to the device under test 10 other than the test target. Therefore, each device under test 10 can be put into a test standby state early.

[0046] Furthermore, since the second voltage is output in parallel with the measurement by the current sensor 203, it is possible to put another device under test 10 into a standby state while testing the device under test 10 under test, which makes it possible to reliably speed up the start of testing for each device under test 10.

[0047] Furthermore, since the second voltage source 23 is selectively connected to each of the connection terminals 101 of at least one device under test 10 other than the test subject, it is possible to apply the second voltage to the device under test 10 other than the test subject while preventing the second voltage from being applied to the device under test 10 that is the test subject.

[0048] Furthermore, the devices under test 10 to which the second voltage is applied include the device under test 10 to be measured next after the device under test 10 to be tested. Therefore, the device under test 10 to be measured next can be put into a test standby state, and the start of the test for that device under test 10 can be accelerated.

[0049] Furthermore, since the constant current generating voltage measuring section 25 is connected between the second voltage source 23 and the second switch section 24, a common path can be used between the constant current generating voltage measuring section 25 and each device under test and between the second voltage source 23 and each device under test 10. Furthermore, by connecting the second voltage source 23 to the path between the constant current generating voltage measuring section 25 and each device under test 10, the test apparatus 2 can be formed.

[0050] Furthermore, since second voltage source 23 is an amplifier that amplifies the first voltage from first voltage source 201, it is possible to insulate the input side from the output side of second voltage source 23. Therefore, it is possible to prevent a decrease in measurement accuracy caused by the current from first voltage source 201 also flowing to the second voltage source 23 side.

[0051] Furthermore, since the second voltage is the same as the first voltage, a device under test 10 other than the test target can be placed in a standby state so that it can be tested immediately.

[0052] Furthermore, since the second voltage is closer to the first voltage than the ground voltage of the device under test 10, it is possible to reliably put a device under test 10 other than the test subject into a standby state for testing.

[0053] (Operation of Test Apparatus 2) Figure 2 shows the operation of test apparatus 2. Note that this figure shows the operation of test apparatus 2 related to the measurement of constant voltage generation current measurement section 20. Test apparatus 2 may test each device under test 10 by performing the processes of steps S10 to S26. In this operation, first voltage source 201 and second voltage source 202 may continue to output voltage.

[0054] In step S10, the second switch section 24 connects the second voltage source 23 to the connection terminal 101 of at least one other device under test 10 (each device under test 10 is used as an example in this embodiment) that is different from the device under test 10 that is the test target. This allows a second voltage (a voltage having the same magnitude as the first voltage in this embodiment as an example) to be output to the connection terminal 101 of each device under test 10.

[0055] In step S12, the test controller 28 selects one of the n devices under test 10 as the device under test 10 to be tested. The test controller 28 may select a different device under test 10 for each process of step S12, or may select the first device under test 10 to the nth device under test 10 in order.

[0056] In step S14, the second switch section 24 disconnects the connection terminal 101 of the device under test 10 being tested from the second voltage source 23. As a result, the second voltage source 23 is connected to the connection terminal 101 of at least one other device under test 10 (each device under test 10 other than the test target, as an example in this embodiment) different from the device under test 10 being tested, and a second voltage (a voltage having the same magnitude as the first voltage, as an example in this embodiment) may be output to the connection terminal 101 of the device under test 10 other than the test target.

[0057] In step S16, the first switch section 21 connects the connection terminal 101 of the device under test 10 to be tested to the first voltage source 201. This may output a first voltage to the connection terminal 101 of the device under test 10 to be tested. The process of step S16 may be performed simultaneously with the process of step S14.

[0058] In step S18, the current sensor 203 measures the electrical characteristics of the device under test 10 (in this embodiment, as an example, the current flowing through the device under test 10) in response to the first voltage source 201 being connected to the device under test 10.

[0059] In step S20, the judging section 27 judges whether the device under test 10 under test is good or bad based on the measurement result by the current sensor 203. The judging section 27 may judge the device under test 10 as good if the magnitude of the measured current is within a reference range, or may judge the device under test 10 as bad if the magnitude of the measured current is outside the reference range. The judging section 27 may judge the device under test 10 under test as bad if the rate of change in the value of the measurement result by the current sensor 203 does not become equal to or less than a reference value within a reference time after the first voltage source 201 is connected to the device under test 10 under test, i.e., after the processing of step S16 is performed. As a result, the device under test 10 under test may be judged as bad if the current flowing through the device under test 10 under test is unstable. The reference time may be shorter than the time required for the potential of the device under test 10 to stabilize after the first voltage source 201 applies a voltage to the device under test 10 under test when the second voltage source 23 does not apply a voltage to a device under test 10 other than the test target.

[0060] In step S22, the first switch section 21 disconnects the connection terminal 101 of the device under test 10 to be tested from the first voltage source 201.

[0061] In step S24, the second switch section 24 connects the connection terminal 101 of the device under test 10 to be tested to the second voltage source 23. This may output the second voltage to the connection terminal 101 of each device under test 10. The process of step S24 may be performed simultaneously with the process of step S22.

[0062] In step S26, the test controller 28 determines whether or not all n devices under test 10 have been selected in step S12. If it is determined that all of the devices under test 10 have not been selected (step S26; No), the process may proceed to step S12. If it is determined that all of the devices under test 10 have been selected (step S26; Yes), the operation may end.

[0063] According to the above operation, the device under test 10 under test is determined to be defective when the rate of change in the value of the measurement result does not become equal to or less than the reference value within the reference time after the first voltage source 201 is connected to the device under test 10 under test. Therefore, the device under test 10 under test can be determined to be defective when the reference time has elapsed without waiting for the value of the measurement result to stabilize.

[0064] (Operation Waveforms) Figure 3 shows the operation waveforms of the test device 2. Note that this figure shows the waveforms of the measurement operation by the constant voltage generation current measurement unit 20, among the operations of the test device 2. In the figure, the horizontal axis represents time. The operation waveforms of "SW_1" to "SW_n" represent control signals for the first switch 210 to the nth switch 210 in the first switch unit 21, with a high level indicating on and a low level indicating off. The operation waveforms of "SW_1G" to "SW_nG" represent control signals for the first switch 240 to the nth switch 240 in the second switch unit 24, with a high level indicating on and a low level indicating off. The operation waveform of "applied voltage" represents the voltage output from the first voltage source 201 and the second voltage source 23. The measurement timing represents the measurement timing by the current sensor 203.

[0065] At time t0, each switch 240 of the second switch section 24 is turned on, connecting each device under test 10 to the second voltage source 23. Also, the first voltage source 201 and the second voltage source 23 start outputting voltages, which causes each device under test 10 to reach the standby potential.

[0066] At time t1, only the first switch 210 in the first switch section 21 is turned on, and only the first switch 240 in the second switch section 24 is turned off. As a result, a current flows through the device under test 10 (here, the first device under test 10) in response to the application of the first voltage from the first voltage source 201, and the current is measured at time t11.

[0067] Subsequently, at time t2, only the second switch 210 in the first switch section 21 is turned on, and only the second switch 240 in the second switch section 24 is turned off. As a result, a current flows through the device under test 10 (here, the second device under test 10) in response to the application of the first voltage from the first voltage source 201, and the current is measured at time t21.

[0068] Thereafter, in a similar manner, at time tN (where N is a natural number satisfying 3≦N≦n), only the Nth switch 210 in the first switch section 21 is turned on, and only the Nth switch 240 in the second switch section 24 is turned off. As a result, a current flows through the device under test 10 (here, the Nth device under test 10) in response to the first voltage being applied from the first voltage source 201, and this current is measured at time tN1.

[0069] In the first embodiment described above, the test apparatus 2 has been described as having the constant current generating voltage measuring unit 25, the third switch unit 26, the determination unit 27, and the test controller 28, but any of these may be omitted. For example, the determination unit 27 and the test controller 28 may be provided outside the test apparatus 1. If the test apparatus 2 does not have the constant current generating voltage measuring unit 25, it may also not have the third switch unit 26.

[0070] Furthermore, although it has been described that the first switch section 21 and the second switch section 24 switch the connection so that each device under test 10 is connected to either the first voltage source 201 or the second voltage source 23, at least one device under test 10 may be temporarily connected to both the first voltage source 201 and the second voltage source 23.

[0071] Second Embodiment Fig. 4 shows a test system 1A according to this embodiment. In the test system 1A according to this embodiment, components that are substantially the same as those in the test system 1 shown in Fig. 1 are designated by the same reference numerals, and descriptions thereof will be omitted.

[0072] The test apparatus 2A of the test system 1A has, instead of the second switch section 24, a plurality of resistors 241 (n resistors 241 in this embodiment, as an example) provided on each of the wirings 245 (n wirings 245 in this embodiment, as an example) connecting the second voltage source 23 to each of the connection terminals 101 of a plurality of devices under test 10 (n devices under test 10 in this embodiment, as an example). When the wiring 245 and the current path from the first voltage source 201 to the device under test 10 have a common portion, the resistor 241 may be provided in a portion of the wiring 245 that is different from the current path from the first voltage source 201 to the device under test 10.

[0073] As a result, the second voltage source 23 in this embodiment may be able to apply the second voltage to each of the n devices under test 10, including the device under test 10 to be measured. However, in the test apparatus 2A according to this embodiment, at least one of adjusting the magnitude of the second voltage relative to the first voltage and adjusting the magnitude of the resistor 241 is performed in advance, so that a current caused by the voltage from the second voltage source 23 does not flow through the resistor 241 connected to the device under test 10 to be tested. As an example, the second voltage may have the same magnitude as the first voltage. The resistance values ​​of the n resistors 241 may be the same.

[0074] According to the above-described test apparatus 2A, since the resistors 241 are provided on the wirings 245 connecting the second voltage source 23 to the connection terminals 101 of the n number of devices under test 10, each device under test 10 other than the test target can be placed in a test standby state. Furthermore, unlike the first embodiment, the device under test 10 other than the test target can be settled to the standby potential without switching the second switch section 24, thereby eliminating the need for a configuration or control for switching. Furthermore, since it is possible to prevent current from flowing through the device under test 10 that is the test target due to the voltage from the second voltage source 23, it is possible to prevent a decrease in measurement accuracy.

[0075] The test apparatus 2A described above may perform measurements using the constant voltage generating current measuring section 20 in the same manner as in FIG. 2 , except that steps S10, S14, and S24 are not performed. Furthermore, the current sensor 203 of the test apparatus 2A may be calibrated in step S18. For example, the current sensor 203 may adjust a measurement value when the first switch section 21 connects the device under test 10 to the first voltage source 201, based on a measurement value when the first switch section 21 does not connect the device under test 10 to the first voltage source 201. This allows for the acquisition of a calibrated, accurate measurement value. The current measurement value when the first switch section 21 does not connect the device under test 10 to the first voltage source 201 may be a measurement error caused by current flowing through the wiring 245. This may be measured in advance and stored in the test apparatus 2A before the device under test 10 and the first voltage source 201 are connected or before the start of testing. The current sensor 203 may calculate a calibrated measurement value by subtracting the measurement error from the actual measurement value measured by the current sensor 203 when the first switch section 21 connects the device under test 10 to the first voltage source 201. The current sensor 203 may perform the calibration in cooperation with the test controller 28.

[0076] (Operational Waveforms) Figure 5 shows the operational waveforms of the test device 2A. In the figure, the horizontal axis represents time. The operational waveforms of "SW_1" to "SW_n" represent control signals for the first switch 210 to the nth switch 210 in the first switch section 21, with a high level representing on and a low level representing off. The operational waveform of "applied voltage" represents the voltage output from the first voltage source 201 and the second voltage source 23. The measurement timing represents the measurement timing by the current sensor 203.

[0077] In this operation, the first voltage source 201 and the second voltage source 23 start outputting voltages in advance, which causes each device under test 10 to be at standby potential.

[0078] At time t1, only the first switch 210 in the first switch section 21 is turned on. As a result, a current flows through the device under test 10 (here, the first device under test 10) in response to the application of a first voltage from the first voltage source 201, and the current is measured at time t11.

[0079] Subsequently, at time t2, only the second switch 210 in the first switch section 21 is turned on. As a result, a current flows through the device under test 10 (here, the second device under test 10) in response to the application of the first voltage from the first voltage source 201, and the current is measured at time t21.

[0080] Thereafter, in a similar manner, at time tN (where N is a natural number satisfying 3≦N≦n), only the Nth switch 210 in the first switch section 21 is turned on. As a result, a current flows through the device under test 10 (here, the Nth device under test 10) in response to the application of the first voltage from the first voltage source 201, and the current is measured at time tN1.

[0081] Although the above embodiment has been described as the case where the second voltage source 23 outputs a voltage of the same magnitude as that of the first voltage source 201, it may output a voltage of a different magnitude. Even in this case, it is possible to settle a device under test 10 other than the test target to a predetermined potential and put it into a test standby state, thereby speeding up the start of testing for each device under test 10.

[0082] Furthermore, although the second voltage source 23 has been described as an amplifier that amplifies the first voltage output from the first voltage source 201, it may also be a battery, rectifier, converter, etc. that outputs a voltage independently of the first voltage source 201.

[0083] Furthermore, although the constant voltage generating current measuring section 20 has been described as including an amplifier 202 with a gain of 1 between the first voltage source 201 and the current sensor 203, the amplifier 202 may not be included. Furthermore, although the first voltage source 201 has been described as a battery, a rectifier, or a converter, the first voltage source 201 may also include an amplifier that amplifies the output voltage to the first voltage. The gain of the amplifier included in the first voltage source 201 may be greater than 1. If the constant voltage generating current measuring section 20 does not include an amplifier 202 separate from the first voltage source 201, the current flowing from the second voltage source 23 to each device under test 10 other than the test target may be greater than the current flowing from the first voltage source 201 to the device under test 10 that is the test target. For example, the wiring resistance of the current path from the second voltage source 23 to each device under test 10 may be smaller than the wiring resistance of the current path from the first voltage source 201 to each device under test 10. This allows the device under test 10 other than the test target to be quickly adjusted to a desired potential and placed in a standby state for testing.

[0084] In addition, although the description has been given in which the judging section 27 judges the target device under test 10 to be defective when the rate of change of the measurement value measured by the current sensor 203 does not become equal to or less than the reference value within a reference time after the first voltage source 201 applies a voltage to the target device under test 10, other methods may be used for the judgment. For example, the judging section 27 may make the judgment based on the measurement value obtained after the reference time has elapsed since the first voltage source 201 applied a voltage to the target device under test 10. The reference time may be the longest time measured as a result of preliminary tests performed on multiple devices under test 10 during the manufacturing stage of the test apparatuses 2 and 2A, from the time the first voltage source 201 applied a voltage to the target device under test 10 to the time the potential of the device under test 10 stabilizes. The reference time may be shorter than the time measured from the time the first voltage source 201 applied a voltage to the target device under test 10 to the time the potential of the device under test 10 stabilizes when the second voltage source 23 does not apply a voltage to a device under test 10 other than the test target.

[0085] Furthermore, the test system 1, 1A may include, as an example of a first measurement section, a sensor (for example, a voltage sensor) that measures a value corresponding to a voltage generated in the device under test 10 under test in response to a first current of a predetermined magnitude flowing from a constant current source, instead of the current sensor 203 that measures a value corresponding to a current flowing in the device under test 10 under test in response to the application of a first voltage from the first voltage source 201. In this case, the test system 1, 1A may include a constant current source that outputs the first current instead of the first voltage source 201, and the first switch section 21 may connect the connection terminal 101 of the device under test 10 under test, among the connection terminals 101 of the n devices under test 10, to the constant current source. Even in such a case, the second voltage is output from the second voltage source 23 to the connection terminal 101 of the device under test 10 other than the device under test under test measured by the voltage sensor, so that the device under test 10 other than the device under test can be settled to a predetermined potential and placed in a test standby state.

[0086] Various embodiments of the present invention may be described with reference to flowcharts and block diagrams, where the blocks may represent (1) stages of a process in which operations are performed or (2) sections of apparatus responsible for performing the operations. Particular stages and sections may be implemented by dedicated circuitry, programmable circuitry provided with computer-readable instructions stored on a computer-readable medium, and / or a processor provided with computer-readable instructions stored on a computer-readable medium. Dedicated circuitry may include digital and / or analog hardware circuitry, and may include integrated circuits (ICs) and / or discrete circuits. Programmable circuitry may include reconfigurable hardware circuitry including logical AND, OR, XOR, NAND, NOR, and other logic operations, flip-flops, registers, memory elements such as field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), and the like.

[0087] A computer-readable medium may include any tangible device capable of storing instructions that are executed by an appropriate device, such that the computer-readable medium having instructions stored thereon comprises an article of manufacture containing instructions that can be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of computer-readable media may include electronic, magnetic, optical, electromagnetic, and semiconductor storage media. More specific examples of computer-readable media may include floppy disks, diskettes, hard disks, random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), electrically erasable programmable read-only memories (EEPROMs), static random access memories (SRAMs), compact disc read-only memories (CD-ROMs), digital versatile discs (DVDs), Blu-ray (RTM) discs, memory sticks, integrated circuit cards, and the like.

[0088] The computer readable instructions may include either assembler instructions, Instruction Set Architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk®, JAVA®, C++, etc., and conventional procedural programming languages ​​such as the “C” programming language or similar programming languages.

[0089] The computer-readable instructions may be provided to a processor or programmable circuitry of a general-purpose computer, special-purpose computer, or other programmable data processing apparatus, either locally or over a local area network (LAN), a wide area network (WAN) such as the Internet, etc., which executes the computer-readable instructions to create means for performing the operations specified in the flowcharts or block diagrams. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, etc.

[0090] 6 illustrates an example of a computer 2200 in which aspects of the present invention may be embodied, in whole or in part. Programs installed on the computer 2200 may cause the computer 2200 to function as or perform operations associated with an apparatus or one or more sections of the apparatus according to embodiments of the present invention, and / or to perform a process or steps of a process according to embodiments of the present invention. Such programs may be executed by the CPU 2212 to cause the computer 2200 to perform specific operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

[0091] A computer 2200 according to this embodiment includes a CPU 2212, a RAM 2214, a graphics controller 2216, and a display device 2218, which are interconnected by a host controller 2210. The computer 2200 also includes input / output units such as a communication interface 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive, which are connected to the host controller 2210 via an input / output controller 2220. The computer also includes legacy input / output units such as a ROM 2230 and a keyboard 2242, which are connected to the input / output controller 2220 via an input / output chip 2240.

[0092] The CPU 2212 operates according to programs stored in the ROM 2230 and RAM 2214, thereby controlling each unit. The graphics controller 2216 acquires image data generated by the CPU 2212 into a frame buffer or the like provided in the RAM 2214 or into the graphics controller 2216 itself, and causes the image data to be displayed on the display device 2218.

[0093] The communication interface 2222 communicates with other electronic devices via a network. The hard disk drive 2224 stores programs and data used by the CPU 2212 in the computer 2200. The DVD-ROM drive 2226 reads programs or data from the DVD-ROM 2201 and provides the programs or data to the hard disk drive 2224 via the RAM 2214. The IC card drive reads programs and data from an IC card and / or writes programs and data to an IC card.

[0094] ROM 2230 stores therein a boot program or the like that is executed by computer 2200 upon activation, and / or programs that depend on the hardware of computer 2200. I / O chip 2240 may also connect various I / O units to I / O controller 2220 via parallel ports, serial ports, keyboard ports, mouse ports, etc.

[0095] The programs are provided by a computer-readable medium such as a DVD-ROM 2201 or an IC card. The programs are read from the computer-readable medium, installed in the hard disk drive 2224, RAM 2214, or ROM 2230, which are also examples of computer-readable media, and executed by the CPU 2212. Information processing described in these programs is read by the computer 2200, and brings about cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be configured by implementing information manipulation or processing in accordance with the use of the computer 2200.

[0096] For example, when communication is performed between computer 2200 and an external device, CPU 2212 may execute a communication program loaded in RAM 2214 and instruct communication interface 2222 to perform communication processing based on the processing described in the communication program. Under the control of CPU 2212, communication interface 2222 reads transmission data stored in a transmission buffer processing area provided in RAM 2214, hard disk drive 2224, DVD-ROM 2201, or a recording medium such as an IC card, and transmits the read transmission data to the network, or writes received data received from the network to a reception buffer processing area or the like provided on the recording medium.

[0097] Furthermore, the CPU 2212 may cause all or a necessary portion of a file or database stored on an external recording medium such as the hard disk drive 2224, the DVD-ROM drive 2226 (DVD-ROM 2201), an IC card, etc. to be read into the RAM 2214, and may perform various types of processing on the data on the RAM 2214. The CPU 2212 then writes back the processed data to the external recording medium.

[0098] Various types of information, such as various types of programs, data, tables, and databases, may be stored on the recording medium and may undergo information processing. The CPU 2212 may perform various types of processing on data read from the RAM 2214, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search / replacement, etc., as described throughout this disclosure and specified by the instruction sequences of the programs, and write the results back to the RAM 2214. The CPU 2212 may also search for information in a file, database, etc. on the recording medium. For example, if multiple entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored on the recording medium, the CPU 2212 may search for an entry that matches a condition specified by the attribute value of the first attribute from among the multiple entries, read the attribute value of the second attribute stored in the entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

[0099] The above-described programs or software modules may be stored in a computer-readable medium on or near the computer 2200. A recording medium such as a hard disk or RAM provided in a server system connected to a dedicated communication network or the Internet can also be used as a computer-readable medium, thereby providing the programs to the computer 2200 via the network.

[0100] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0101] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order.

[0102] 1 Test system 2 Test equipment 10 Device under test 20 Constant voltage generation current measurement section 21 First switch section 23 Second voltage source 24 Second switch section 25 Constant current generation voltage measurement section 26 Third switch section 27 Judgment section 28 Test controller 101 Connection terminal 201 First voltage source 202 Amplifier 203 Current sensor 210 Switch 240 Switch 245 Wiring 261 Switch 262 Switch 2200 Computer 2201 DVD-ROM 2210 Host controller 2212 CPU 2214 RAM 2216 Graphics controller 2218 Display device 2220 Input / output controller 2222 Communication interface 2224 Hard disk drive 2226 DVD-ROM drive 2230 ROM 2240 Input / Output Chip 2242 Keyboard

Claims

1. A test apparatus comprising: a first power supply that outputs a first voltage of a predetermined magnitude or a first current of a predetermined magnitude; a first switch section that connects a connection terminal of a device under test to be tested among a plurality of devices under test to the first power supply; a first measurement section that measures electrical characteristics of the device under test to be tested in response to the first power supply being connected to the device under test; and a second voltage source that outputs a second voltage of a predetermined magnitude to the connection terminal of at least one other device under test different from the device under test to be tested among the plurality of devices under test.

2. The test apparatus of claim 1, wherein the current path between the second voltage source and the at least one other device under test and the current path between the first power source and the device under test being tested are separate paths from each other.

3. The test device according to claim 1, wherein the second voltage source outputs a voltage in parallel with measurement by the first measurement section.

4. The test apparatus according to claim 1, further comprising a second switch section for selectively connecting said second voltage source to each of the connection terminals of said at least one other device under test.

5. The test apparatus according to claim 4, wherein the at least one other device under test includes a device under test among the plurality of devices under test that is measured by the first measurement section next to the device under test that is the test target.

6. The test apparatus of claim 4, further comprising a second measuring unit that measures a value corresponding to a voltage generated in the device under test as a result of a current of a predetermined magnitude being passed through the device under test in response to the first voltage being applied from the first power supply, at a timing different from the timing of measurement by the first measuring unit, the second measuring unit being connected between the second voltage source and the second switch unit, and the second switch unit connecting the second measuring unit to the device under test as a result of the second measuring unit performing measurement.

7. The test apparatus according to claim 1, further comprising a plurality of resistors provided in each of the wiring lines connecting said second voltage source and each of said connection terminals of said plurality of devices under test.

8. The test apparatus of claim 7, wherein the first measurement section adjusts the measurement value when the first switch section connects the device under test to the first power supply in accordance with the measurement value when the first switch section does not connect the device under test to the first power supply.

9. The test apparatus according to claim 1, wherein the first power supply outputs a predetermined first voltage, and the second voltage source is an amplifier that amplifies the first voltage output from the first power supply by a preset gain.

10. The test apparatus of claim 1, wherein the first power supply outputs a predetermined first voltage, and the second voltage is a voltage having the same magnitude as the first voltage.

11. The test apparatus of claim 1, wherein the first power supply outputs a predetermined first voltage, and the second voltage is closer to the first voltage than a ground voltage of the devices under test.

12. The test apparatus of claim 1, wherein the current passed by the second voltage source to the at least one other device under test is greater than the current passed by the first voltage source to the device under test being tested.

13. The test apparatus of claim 1, further comprising a judgment section which judges whether the device under test of the test target is good or bad based on the measurement result by the first measurement section, and the judgment section judges the device under test of the test target to be defective if the rate of change in the value of the measurement result by the first measurement section does not become equal to or lower than a reference value within a reference time after the first power supply is connected to the device under test of the test target.

14. The test apparatus of claim 1, wherein the first measuring section measures a value corresponding to a current flowing in the device under test of the test subject in response to the application of the first voltage from the first power supply, or measures a value corresponding to a voltage generated in the device under test of the test subject in response to the first current flowing from the first power supply.

15. A testing method comprising the steps of: connecting a connection terminal of a device under test to be tested among connection terminals of a plurality of devices under test to a first power supply that outputs a first voltage of a predetermined magnitude or a first current of a predetermined magnitude, and applying a second voltage of a predetermined magnitude from a second voltage source to the connection terminal of at least one other device under test among the plurality of devices under test that is different from the device under test to be tested; and measuring electrical characteristics of the device under test to be tested in response to the first power supply being connected to the device under test to be tested.

Images