Inspection device and inspection method

Abstract

To provide an inspection device and an inspection method that shorten a measurement time.SOLUTION: An inspection device includes: a power supply part that applies a predetermined output voltage to a plurality of inspected bodies; a switch part that switches each inspected body measuring a current; a measurement part that measures the current of each inspected body selected by the switch part; and a control part that controls the switch part. The control part switches a sequential system that performs a current measurement for predetermined times against the other inspected bodies by switching the switch part after the current measurement is performed for the predetermined times to one inspected body on the basis of a setting value related to the set current measurement and a scanning system that switches the switch part after the current measurement is performed to the one inspected body to repeat an implementation of the current measurement to the other inspected bodies for the predetermined times.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to an inspection apparatus and an inspection method. [Background technology]

[0002] Patent Document 1 discloses a device inspection circuit that inspects the electrical characteristics of a semiconductor device to be inspected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-25519 A Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, in an inspection apparatus for measuring the electrical characteristics of a plurality of semiconductor devices, there is a demand for shortening the measurement time.

[0005] In one aspect, the present disclosure provides an inspection device and an inspection method that shortens measurement time. [Means for solving the problem]

[0006] In order to solve the above problem, according to one aspect, an inspection device is provided having a power supply unit that applies a predetermined output voltage to multiple test objects, a switching unit that switches between the test objects for which current is to be measured, a measurement unit that measures the current of the test object selected by the switching unit, and a control unit that controls the switching unit, wherein the control unit switches between a sequential mode in which current measurements are performed a predetermined number of times on one test object and then switches the switching unit to perform current measurements a predetermined number of times on other test objects, based on a set value for current measurement, and a scan mode in which current measurements are performed on one test object and then switches the switching unit to perform current measurements on other test objects, and this process is repeated a predetermined number of times. Effect of the Invention

[0007] According to one aspect, it is possible to provide an inspection device and an inspection method that shorten the measurement time. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic cross-sectional view illustrating an example of a configuration of an inspection device according to the present embodiment. [Diagram 2] 1 is an example of a circuit diagram showing a circuit configuration of an inspection device according to an embodiment of the present invention. [Diagram 3] 4 is an example of a time chart illustrating a current measuring method. [Figure 4] 13 is an example of a graph showing the relationship between the number of averaging operations and the current measurement time. [Diagram 5] 10 is a flowchart showing an example of control of a computer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0010] <Inspection equipment> An inspection device 10 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is an example of a schematic cross-sectional view illustrating the configuration of the inspection device 10 according to this embodiment.

[0011] The inspection apparatus 10 is an apparatus that inspects the electrical characteristics of each of a plurality of semiconductor devices (devices under test, DUT) formed on a wafer (substrate) W. Note that the substrate having the device under test is not limited to the wafer W, but may include a carrier on which a semiconductor device is arranged, a glass substrate, a single chip, and the like. The inspection apparatus 10 includes an accommodation chamber 12 that accommodates a chuck 11 on which the wafer W is placed, a loader 13 that is disposed adjacent to the accommodation chamber 12, and a tester 14 that is disposed to cover the accommodation chamber 12.

[0012] The accommodation chamber 12 has a hollow housing shape. A chuck 11 on which the wafer W is placed and a probe card 15 arranged to face the chuck 11 are accommodated inside the accommodation chamber 12. The probe card 15 has a large number of needle-shaped probes (contact terminals) 16 arranged in correspondence with electrode pads and solder bumps provided in correspondence with the electrodes of each semiconductor device on the wafer W.

[0013] The chuck 11 has a fixing mechanism (not shown) for fixing the wafer W to the chuck 11. This prevents the wafer W from being displaced relative to the chuck 11. The accommodation chamber 12 is also provided with a moving mechanism (not shown) for moving the chuck 11 horizontally and vertically. This adjusts the relative positions of the probe card 15 and the wafer W, so that electrode pads and solder bumps provided corresponding to the electrodes of each semiconductor device are brought into contact with each probe 16 of the probe card 15.

[0014] The loader 13 takes out a wafer W on which semiconductor devices are arranged from a FOUP (not shown) which is a transport container, and places it on a chuck 11 inside the storage chamber 12, and also removes the wafer W which has been inspected from the chuck 11 and stores it in the FOUP.

[0015] The probe card 15 is connected to the tester 14 via the interface 17, and when each probe 16 contacts an electrode pad or a solder bump provided corresponding to the electrode of each semiconductor device on the wafer W, each probe 16 supplies power from the tester 14 to the semiconductor device via the interface 17, or transmits a signal from the semiconductor device to the tester 14 via the interface 17.

[0016] The tester 14 has a test board (not shown) that reproduces part of the circuit configuration of a motherboard on which a semiconductor device is mounted, and the test board is connected to a computer 18 that judges the quality of the semiconductor device based on signals from the semiconductor device and controls it. By changing the test board in the tester 14, it is possible to reproduce the circuit configurations of a variety of motherboards.

[0017] Next, the circuit configuration of the inspection device 10 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is an example of a circuit diagram showing the circuit configuration of the inspection device 10 according to this embodiment.

[0018] The inspection apparatus 10 is an inspection apparatus that inspects electrical characteristics of a plurality of semiconductor devices 1. In the example shown in Fig. 2, the inspection apparatus 10 will be described as an inspection apparatus that inspects 16 semiconductor devices 1. In the following description, the 16 semiconductor devices 1 will also be referred to as DUT1, DUT2, ..., DUT16, respectively.

[0019] A tester 14 (see FIG. 1) of the inspection apparatus 10 includes a current sense amplifier 2, a current detection resistor 3, an amplifier 4, a digital-to-analog converter (DAC) 5, a switching unit 6, an analog-to-digital converter (ADC) 7, and a controller (control unit) 8. The current sense amplifier 2, the current detection resistor 3, and the amplifier 4 form a power supply unit 9 that supplies power to a semiconductor device (DUT) 1. Sixteen power supply units 9 are provided corresponding to the semiconductor devices 1.

[0020] The computer 18 issues commands to a controller 8 such as an FPGA (Field Programmable Gate Array) to control the tester 14 .

[0021] The controller 8 outputs a set voltage signal (digital signal) to each DAC 5. The DAC 5 converts the digital signal into an analog signal and outputs it to the amplifier 4. The amplifier 4 applies a predetermined output voltage to the semiconductor device 1 based on the input analog signal.

[0022] In addition, a current detection resistor 3 for measuring a current supplied from the amplifier 4 to the semiconductor device 1 is connected to the output of the amplifier 4. When a predetermined output voltage is applied to the semiconductor device 1, a potential difference corresponding to the current supplied from the amplifier 4 to the semiconductor device 1 is generated across the current detection resistor 3. The current sense amplifier 2 amplifies the potential difference across the current detection resistor 3, and outputs the amplified voltage signal (analog signal) to the ADC 7 via the switching unit 6.

[0023] That is, the power supply unit 9 receives a set voltage signal (digital signal) from the controller 8. The power supply unit 9 applies a predetermined output voltage to the semiconductor device 1 based on the input set voltage signal (digital signal). The power supply unit 9 also outputs an amplified voltage signal (analog signal) to the ADC 7 via the switching unit 6 as a signal corresponding to the current supplied to the semiconductor device 1.

[0024] The switching unit 6 is controlled by the controller 8, and switches the power supply unit 9 to be connected to the ADC 7, among the multiple power supply units 9. In other words, the switching unit 6 switches the semiconductor device 1 for measuring a current, among the multiple semiconductor devices 1. The switching unit 6 has multiple relay switches whose opening and closing are controlled by the controller 8. One end of the relay switch is connected to a corresponding power supply unit 9. The other end of the relay switch is connected to the ADC 7. The controller 8 switches the power supply unit 9 to be connected to the ADC 7 by switching the relay switch.

[0025] The ADC 7 receives an amplified voltage signal (analog signal) from the power supply unit 9 (current sense amplifier 2) selected by the switching unit 6. The ADC 7 converts the analog signal into a digital signal and outputs it to the controller 8. The controller 8 also outputs the digital signal to the computer 18. In this way, the controller 8 measures the current supplied to the semiconductor device 1. In other words, the ADC 7, the controller 8, and the computer 18 constitute a measurement unit that measures the current supplied to the semiconductor device 1 selected by the switching unit 6.

[0026] Furthermore, the inspection device 10 inspects a plurality of semiconductor devices 1 (16 in the example of FIG. 2). For this reason, the inspection device 10 has a plurality of power supply units 9 (16 in the example of FIG. 2) corresponding to the semiconductor devices 1. Meanwhile, the inspection device 10 has one ADC 7 for the plurality of power supply units 9. This allows the inspection device 10 to measure the current supplied to the plurality of semiconductor devices 1 with one ADC 7 by switching the channel of the switching unit 6.

[0027] Next, a current measurement method will be described with reference to FIG. 3. FIG. 3 is an example of a time chart illustrating the current measurement method. Here, the inspection device 10 performs n current measurements on one semiconductor device 1 and averages the measurements. This allows for accurate current measurement. That is, the inspection device 10 performs n current measurements on each of the 16 semiconductor devices 1 (DUT1 to DUT16), which is the average number of times. In the following description, the time required to perform n current measurements on each of the 16 DUTs is referred to as the "current measurement time."

[0028] Here, the time from when the current measurement is started until the next current measurement is permitted for the same semiconductor device 1 is defined as an interval time t1.

[0029] Furthermore, when switching the channel of the switching unit 6, a waiting time is required for the switching unit 6, etc. The time from switching the channel of the switching unit 6 to starting current measurement is defined as a channel waiting time (CH WAIT) t2.

[0030] The time required for one measurement of the semiconductor device 1 is set to t3.

[0031] The interval time t1 and the number of averaging times n are designated by the user in accordance with, for example, the inspection of the semiconductor device 1, and are input to the computer 18. The channel waiting time t2 and the time t3 for one measurement are values ​​that are set in advance according to, for example, the characteristics of the inspection apparatus 10 (e.g., the response time of the switching unit 6 and the ADC 7, etc.), and are stored in advance in the computer 18.

[0032] 3(a) is an example of a time chart for explaining the sequential current measurement method. In the sequential current measurement method, current measurements are repeatedly performed n times on one DUT 1, the channel of the switching unit 6 is switched, and then current measurements are repeatedly performed n times on DUT 2. This is repeated up to DUT 16. That is, in the sequential current measurement method, after current measurements are performed a predetermined number of times on one semiconductor device 1, the switching unit 6 is switched, and current measurements are performed a predetermined number of times on another semiconductor device 1.

[0033] In the sequential current measurement method, first, the channel of the switching unit 6 is switched to measure DUT1. After a channel waiting time t2, the first measurement of DUT1 is performed. If t1>t3, the second measurement of DUT1 is performed after the interval time t1 has elapsed. On the other hand, if t1≦t3, the second measurement of DUT1 is performed immediately after the first measurement of DUT1. The measurement of DUT1 is continued until it reaches n times.

[0034] Next, the channel of the switching unit 6 is switched so as to measure DUT 2. After the channel waiting time t2, the first measurement of DUT 2 is performed. Thereafter, similarly to the case of DUT 1, measurements of DUT 2 are performed until n measurements have been performed.

[0035] By carrying out this process for DUT1 to DUT16, the current measurement of DUT1 to DUT16 by the inspection device 10 is completed.

[0036] The current measurement time in the sequential method can be calculated using the following equations (1) and (2). When t1>t3, (t1×n+t2)×16 (1) When t1≦t3, (t3×n+t2)×16 (2)

[0037] 3(b) is an example of a time chart for explaining the scan-type current measurement method. In the scan-type current measurement method, the channel of the switching unit 6 is switched to perform a first current measurement on DUT1 to DUT16, and then the channel of the switching unit 6 is switched to perform a second current measurement on DUT1 to DUT16. This is repeated until the number of measurements reaches n. That is, in the scan-type current measurement method, after performing a current measurement on one semiconductor device 1, the switching unit 6 is switched to perform a current measurement on another semiconductor device 1, and this is repeated a predetermined number of times.

[0038] In the scan type current measurement method, first, the channel of the switching unit 6 is switched to measure DUT1. After a channel waiting time t2, the first measurement of DUT1 is performed. Next, the channel of the switching unit 6 is switched to measure DUT2. After a channel waiting time t2, the first measurement of DUT2 is performed. This is performed for DUT1 to DUT16, and the first measurement of DUT1 to DUT16 is completed.

[0039] Here, if t1>(t2+t3)×16, the second measurement of DUT1 to DUT16 is performed after the interval time t1 has elapsed. On the other hand, if t1≦(t2+t3)×16, the second measurement of DUT1 to DUT16 is performed immediately after the first measurement of DUT1 to DUT16. The measurements of DUT1 to DUT16 are performed until n times.

[0040] The current measurement time in the scan method (n tests for each of 16 DUTs) can be calculated using the following equations (3) and (4). If t1>(t2+t3)×16, then t1×n (3) When t1≦(t2+t3)×16, ((t2+t3)×16)×n (4)

[0041] In this way, the current measurement times in the sequential and scan modes are determined by four parameters (set values): interval time t1, channel waiting time t2, one measurement time t3, and the number of averagings n. FIG. 4 is an example of a graph showing the relationship between the number of averagings n and the current measurement time. The horizontal axis indicates the number of averagings n, and the vertical axis indicates the current measurement time. The solid line indicates the current measurement time in the scan mode, and the dashed line indicates the current measurement time in the sequential mode. In the example of FIG. 4, when the number of averagings n is less than n1, the current measurement time in the scan mode is shorter than the current measurement time in the sequential mode. When the number of averagings n is equal to or greater than n1, the current measurement time in the sequential mode is shorter than the current measurement time in the scan mode.

[0042] Based on the set parameters (interval time t1, channel waiting time t2, measurement time per measurement t3, and number of averagings n), the computer 18 selects the measurement method that will shorten the measurement time from the sequential method or the scan method, and performs the inspection using the selected measurement method.

[0043] FIG. 5 is a flow chart showing an example of the control of the computer 18.

[0044] In step S101, the computer 18 accepts input of parameters (setting values). For example, a user inputs an interval time t1 and an averaging count n to the computer 18 in accordance with the inspection of the semiconductor device 1. Note that a channel waiting time t2 and a single measurement time t3 may be input to the computer 18 in advance, or may be input to the computer 18 by the user.

[0045] In step S102, the computer 18 calculates the sequential current measurement time based on the parameters and equations (1) and (2).

[0046] In step S103, the computer 18 calculates the current measurement time in the scan mode based on the parameters and equations (3) and (4).

[0047] In step S104, the computer 18 selects a measurement method based on the calculated current measurement time.

[0048] In step S105, the computer 18 performs current measurement of the semiconductor device 1 (DUT1 to DUT16) using the selected measurement method.

[0049] According to the inspection device 10 of this embodiment, a measurement method that shortens the current measurement time is selected, and the current measurement is performed by the selected measurement method. That is, according to the inspection device 10 of this embodiment, the current measurement time can be shortened by switching between the sequential method and the scan method depending on the inspection conditions.

[0050] The inspection device 10 has been described above, but the present disclosure is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims. [Explanation of symbols]

[0051] 1. Semiconductor device (test object) 2 Current Sense Amplifier 3 Current sensing resistor 4 Amplifier 5 Digital to Analog Converter 6 Switching section 7 Analog-digital converter (measurement section) 8 Controller (control section) 9 Power supply section 10 Inspection equipment 14 Tester 18 Computers W wafer

Claims

1. a power supply unit that applies a predetermined output voltage to a plurality of devices under test; A switching unit for switching the test object for measuring a current; a measurement unit that measures a current of the device under test selected by the switching unit; A control unit that controls the switching unit, The control unit is Based on the current measurement settings you have made, a sequential method in which current measurements are performed a predetermined number of times on one test object, and then the switching unit is switched to perform current measurements a predetermined number of times on another test object; a scanning mode in which, after performing current measurement on one test object, the switching unit is switched to perform current measurement on another test object, and this process is repeated a predetermined number of times. Inspection equipment.

2. The control unit is calculating a current measurement time in the sequential mode and a current measurement time in the scan mode based on the set value; switching between the sequential mode and the scan mode based on the calculated current measurement time; 2. The inspection device according to claim 1.

3. The set value is an interval time that is a time from when a current measurement is started until the next current measurement is permitted for the same test object; and an averaging number, which is the number of times current measurement is repeated for one test object.

3. The inspection device according to claim 1 or 2.

4. The set value is The measurement time for one measurement of the test object, A waiting time until starting current measurement after switching the switching unit.

4. The inspection device according to claim 3.

5. The power supply unit is provided in a plurality of units corresponding to the plurality of devices under test. The inspection device according to any one of claims 1 to 4.

6. 1. A method for testing an inspection apparatus for applying a predetermined output voltage to a plurality of devices under test and measuring a current of a selected device under test, comprising the steps of: a step of calculating a sequential current measurement time in which current measurement is performed a predetermined number of times on one test object and then a predetermined number of times on another test object based on a set value related to the current measurement, and a scan current measurement time in which current measurement is performed a predetermined number of times on one test object and then a predetermined number of times on another test object; selecting the sequential mode or the scan mode based on the calculated current measurement time; and measuring the current of the device under test in a selected manner. Testing method.

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