Multi-channel leakage current acquisition device

Abstract

The present application provides a multi-channel leakage current acquisition device, which relates to the field of power electronics technology. The device includes: a main control unit, a current acquisition unit, a voltage application unit, and a switch unit correspondingly connected to each channel under test; the switch unit correspondingly connected to each channel under test is taken as the core, and the main control unit controls the on-off state of the switch unit correspondingly connected to each channel under test according to the switch control timing information, so that the current acquisition unit can perform high-precision acquisition of the multi-channel leakage current of the wafer under test without affecting the reliability test, and at the same time ensure that the test is carried out normally, and the test voltage at both ends of the wafer chip will not be reduced, which solves the problem that the existing leakage current acquisition scheme cannot collect the leakage current of hundreds or thousands of channels of SiC wafers at a low cost.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a multi-channel leakage current acquisition device. Background Art

[0002] As an important representative of the third generation of power semiconductor materials, silicon carbide (SiC) has a wider bandgap, its breakdown field strength is 10 times that of traditional silicon (Si) materials, and its thermal conductivity is 3 times that of Si materials. Therefore, silicon carbide devices have higher voltage, higher temperature, and higher frequency operating characteristics, which can effectively improve the power level and power density of power converters and improve the overall efficiency of power conversion. At present, reliability testing has become an important link in verifying the application of silicon carbide devices.

[0003] In the related art, for a single SiC wafer, a constant voltage source is applied to the SiC wafer through a voltage application unit to perform a high temperature gate bias test (High Temperature Gate Bias, HTGB for short) and a high temperature reverse bias test (High Temperature Reverse Bias, HTRB for short). During the test, a source measurement unit is used to collect the leakage current of the SiC wafer.

[0004] However, the current source measurement units on the market are priced as high as tens of thousands of yuan, which is a problem of high prices. As a result, the above leakage current collection solution is unable to collect leakage currents of hundreds or thousands of channels of SiC wafers at low cost. Summary of the invention

[0005] The purpose of this application is to provide a multi-channel leakage current acquisition device to address the deficiencies in the prior art, so as to solve the technical problems existing in the prior art.

[0006] To achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0007] In a first aspect, an embodiment of the present application provides a multi-channel leakage current acquisition device, comprising: a main control unit, a current acquisition unit, a voltage application unit, and a switch unit correspondingly connected to each measured channel;

[0008] The input end of each of the measured channels is connected to the positive end of the voltage applying unit, the output end of each of the measured channels is connected to one end of the switch unit corresponding to each of the measured channels, and the other end of the switch unit corresponding to each of the measured channels is connected to the negative end of the voltage applying unit and the input end of the current acquisition unit;

[0009] The output end of the current acquisition unit is connected to the input end of the main control unit; the control end of the switch unit corresponding to each of the measured channels is connected to the output end of the main control unit;

[0010] The main control unit is used to obtain pre-generated switch control timing information, and control the on-off state of the target switch unit corresponding to the output end of the target measured channel according to the switch control timing information, so that the output end of the target measured channel is connected to the input end of the current acquisition unit; and control the on-off state of the switch unit corresponding to the output end of other measured channels except the target measured channel, so that the output end of other measured channels except the target measured channel is connected to the negative terminal of the voltage application unit; wherein the switch control timing information is used to indicate the open or closed state of the switch unit corresponding to each measured channel at at least one moment;

[0011] The current acquisition unit is used to collect the leakage current signal of the target measured channel when the output end of the target measured channel is connected to the input end of the current acquisition unit, and transmit the leakage current signal to the main control unit;

[0012] The main control unit is further used to determine whether the target measured channel has a performance fault according to the leakage current signal of the target measured channel.

[0013] Optionally, the switch unit includes: a collection switch and a test switch;

[0014] The main control unit is specifically used for:

[0015] According to the switch control timing information, the test switch in the target switch unit corresponding to the output end of the target measured channel is controlled to be in an open state and the acquisition switch is controlled to be in a closed state; and the acquisition switches in the switch units corresponding to the output ends of other measured channels except the target measured channel are controlled to be in an open state and the test switches are controlled to be in a closed state.

[0016] Optionally, the main control unit is specifically used to:

[0017] According to the switch control timing information, the test switch in the switch unit corresponding to the output end of the first measured channel is controlled to be in an open state from the first moment to the second moment, and the acquisition switch is controlled to be in a closed state from the first moment to the second moment, and the acquisition switch in the switch unit corresponding to the output ends of other measured channels except the first measured channel is controlled to be in an open state from the first moment to the second moment, and the test switch is controlled to be in a closed state from the first moment to the second moment, wherein the first moment is earlier than the second moment.

[0018] Optionally, the main control unit is specifically used to:

[0019] According to the switch control timing information, the test switch in the target switch unit corresponding to the output end of the second measured channel is controlled to remain in an open state from the second moment to a third moment, and the acquisition switch is controlled to be in a closed state from the second moment to the third moment, and the acquisition switches in the switch units corresponding to the output ends of other measured channels except the second measured channel are controlled to be in an open state from the second moment to the third moment, and the test switches are controlled to be in a closed state from the second moment to the third moment, wherein the second moment is earlier than the third moment.

[0020] Optionally, the acquisition switch includes: a photoelectric relay.

[0021] Optionally, the current collection unit includes: an amplification unit and a collection unit;

[0022] The inverting input end of the amplifying unit is connected to the other end of the acquisition switch in the switch unit corresponding to each of the measured channels;

[0023] The positive phase input terminal of the amplifying unit is connected to the negative terminal of the voltage applying unit which is the other end of the test switch in the switch unit corresponding to each of the channels under test;

[0024] The output end of the amplifying unit is connected to the input end of the collecting unit, and the output end of the collecting unit is connected to the input end of the main control unit;

[0025] The amplifying unit is used to obtain a leakage current signal outputted from the output end of the target measured channel, convert the leakage current signal to generate a converted voltage signal, and transmit the converted voltage signal to the acquisition unit;

[0026] The acquisition unit is used to sample the converted voltage signal, generate a sampled voltage signal, and transmit the sampled voltage signal to the main control unit.

[0027] Optionally, the amplification unit includes: an amplifier and a first resistor;

[0028] One end of the first resistor is connected to the inverting input end of the amplifier and the other end of the acquisition switch in the switch unit corresponding to each of the measured channels; the other end of the first resistor is connected to the output end of the amplifier.

[0029] Optionally, the resistance value of the first resistor is determined based on a sampling range of the acquisition unit.

[0030] Optionally, the main control unit is specifically used to:

[0031] Obtaining a leakage current value of the target measured channel according to the sampled voltage signal;

[0032] It is determined whether the target measured channel has a performance fault according to the leakage current value of the target measured channel.

[0033] Optionally, determining whether the target measured channel has a performance fault according to the leakage current value of the target measured channel includes:

[0034] If the leakage current value of the target measured channel is greater than a preset leakage current threshold, it is determined that the target measured channel has a performance fault.

[0035] The beneficial effects of this application are:

[0036] The embodiment of the present application provides a multi-channel leakage current acquisition device, which includes: a main control unit, a current acquisition unit, a voltage application unit, and a switch unit connected to each measured channel; the input end of each measured channel is connected to the positive end of the voltage application unit, the output end of each measured channel is connected to one end of the switch unit corresponding to each measured channel, and the other end of the switch unit corresponding to each measured channel is connected to the negative end of the voltage application unit and the input end of the current acquisition unit; the output end of the current acquisition unit is connected to the input end of the main control unit; the control end of the switch unit corresponding to each measured channel is connected to the output end of the main control unit; the main control unit is used to obtain pre-generated switch control timing information, and control the target switch connected to the output end of the target measured channel according to the switch control timing information. The switch control timing information is used to indicate the open or closed state of the switch unit corresponding to each measured channel at at least one moment; the current acquisition unit is used to collect the leakage current signal of the target measured channel when the output end of the target measured channel is connected to the input end of the current acquisition unit, and transmit the leakage current signal to the main control unit; the main control unit is also used to determine whether the target measured channel has a performance fault according to the leakage current signal of the target measured channel. In the multi-channel leakage current acquisition device provided by the present solution, the core is a current acquisition unit and a switch unit corresponding to each measured channel, and the main control unit controls the on-off state of the switch unit corresponding to each measured channel according to the switch control timing information, so that the current acquisition unit can perform high-precision acquisition of the multi-channel leakage current of the measured wafer without affecting the HTRB and HTGB tests, and at the same time ensure that the test is carried out normally without reducing the test voltage at both ends of the wafer chip, thereby solving the problem that the existing leakage current acquisition solution cannot acquire the leakage current of hundreds or thousands of channels of SiC wafers at a low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a structural schematic diagram of a multi-channel leakage current acquisition device provided in the related art;

[0039] Figure 2 A schematic diagram of the structure of a multi-channel leakage current acquisition device provided in an embodiment of the present application;

[0040] Figure 3 A schematic diagram of the structure of another multi-channel leakage current acquisition device provided in an embodiment of the present application;

[0041] Figure 4 A switch control timing diagram provided in an embodiment of the present application;

[0042] Figure 5 A schematic diagram of the structure of another multi-channel leakage current acquisition device provided in an embodiment of the present application.

[0043] Icon: 100-multi-channel leakage current acquisition device; 1-main control unit; 2-current acquisition unit; 3-voltage application unit; 4-switch unit; 21-amplification unit; 22-acquisition unit. DETAILED DESCRIPTION

[0044] The technical solution of the specific implementation method is described below in conjunction with the accompanying drawings.

[0045] It should be noted that: although this specification has described the present invention in detail with reference to the above-mentioned embodiments, ordinary technicians in the field should understand that technicians in the relevant technical field can still modify, combine or replace the present invention with equivalents, and all technical solutions and improvements thereto that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

[0046] First, the professional terms involved in this application are introduced.

[0047] 1. High Temperature Reverse Bias (HTRB) test refers to applying reverse bias to the main blocking junction of the device under test at a voltage close to the maximum rated voltage at high temperature to examine the change in leakage current of the device under high temperature and long-term reverse bias voltage.

[0048] 2. High-Temperature Gate Bias (HTGB) test refers to the long-term application of voltage to the gate in a high-temperature environment, which will accelerate the aging of the gate performance and examine the change in leakage current of the device gate under high temperature and long-term voltage.

[0049] Secondly, the prior art involved in this application is introduced.

[0050] As an important representative of the third generation of power semiconductor materials, silicon carbide (SiC) has a wider bandgap, its breakdown field strength is 10 times that of traditional silicon (Si) materials, and its thermal conductivity is 3 times that of Si materials. Therefore, silicon carbide devices have higher voltage, higher temperature, and higher frequency operating characteristics, which can effectively improve the power level and power density of power converters and improve the overall efficiency of power conversion. However, there are still reliability issues in the application of silicon carbide devices. The main reason for the reliability problem of SiC devices is the SiC material manufacturing process.

[0051] At present, it is difficult to improve the manufacturing process of SiC devices in a short period of time. Among them, HTGB test and HTRB test are important items of SiC device reliability test. HTGB and HTRB tests can be used to evaluate the leakage current change trend of SiC devices and verify the reliability and stability of SiC devices.

[0052] In order to reduce screening costs, the reliability screening of SiC has been upgraded from the device level to the wafer level. When SiC wafer reliability testing equipment performs HTRB and HTGB tests on SiC wafers, since there are hundreds or even thousands of bare die on one wafer, it is necessary to consider the problem of fast sampling of the leakage current of each bare die.

[0053] refer to Figure 1 As shown in the figure, when performing HTRB and HTGB tests on SiC wafers, the same high-voltage or low-voltage power supply is usually used to apply voltage to hundreds of parallel-connected dies on the wafer at the same time for testing. The leakage current generated by the HTRB or HTGB test may be as low as nA level. Therefore, a source measure unit (SMU) is generally used to collect the leakage current of the SiC wafer, and while measuring the leakage current, it does not affect the normal progress of the HTRB and HTGB tests.

[0054] However, the current source measurement units on the market are priced as high as tens of thousands of yuan, which is a problem of high prices. As a result, the above leakage current collection solution is unable to collect leakage currents of hundreds or thousands of channels of SiC wafers at low cost.

[0055] In view of the above problems, the present application provides a multi-channel leakage current acquisition device, which includes: a main control unit, a current acquisition unit, a voltage application unit, and a switch unit connected to each channel under test. The current acquisition unit is used as the core, and combined with the switch unit connected to each channel under test, it is possible to perform high-precision acquisition of multi-channel leakage current of a wafer to be tested without affecting HTRB and HTGB tests, and at the same time ensure that the test proceeds normally without reducing the test voltage at both ends of the wafer chip, thereby solving the problem that the existing leakage current acquisition scheme cannot acquire leakage current of hundreds or thousands of channels of SiC wafers at low cost.

[0056] The structure of the protection device provided by the present application will be described in detail through the following embodiments.

[0057] Optionally, refer to Figure 2 As shown, the multi-channel leakage current acquisition device 100 includes: a main control unit 1, a current acquisition unit 2, a voltage application unit 3, and a switch unit 4 correspondingly connected to each measured channel.

[0058] Exemplarily, for example, the main control unit 1 may be a chip having a data processing function.

[0059] The voltage applying unit 3 is used to apply a constant voltage source to each channel under test so as to perform an HTRB or HTGB test on each channel under test. Exemplarily, the voltage applying unit may be a high voltage source meter or a low voltage source meter.

[0060] It should be noted that the channel under test is a bare die on a SiC wafer, that is, the HTRB or HTGB test can be performed on each bare die on the SiC wafer, and during the test, the leakage current of each bare die is sequentially collected by the current acquisition unit 2 to screen the reliability and stability of each bare die on the SiC wafer without affecting the normal progress of the HTRB or HTGB test.

[0061] Continue to refer Figure 2 As shown, the input end of each measured channel is connected to the positive terminal V+ of the voltage applying unit, the output end of each measured channel is connected to one end of the switch unit 4 corresponding to each measured channel, and the other end of the switch unit 4 corresponding to each measured channel is connected to the negative terminal V- of the voltage applying unit and the input end of the current acquisition unit 2;

[0062] The output end of the current acquisition unit 2 is connected to the input end of the main control unit 1; the control end of the switch unit 4 corresponding to each measured channel is connected to the output end of the main control unit 1;

[0063] The main control unit 1 is used to obtain pre-generated switch control timing information, and control the on-off state of the target switch unit connected to the output end of the target measured channel according to the switch control timing information, so that the output end of the target measured channel is connected to the input end of the current acquisition unit 2; and control the on-off state of the switch unit connected to the output end of other measured channels except the target measured channel, so that the output end of other measured channels except the target measured channel is connected to the negative terminal of the voltage application unit; wherein the switch control timing information is used to indicate the open or closed state of the switch unit corresponding to each measured channel at at least one moment.

[0064] Therefore, in the present solution, the on-off state of the switch unit corresponding to each measured channel is mainly controlled by the main control unit according to the pre-generated switch control timing information, so that the output end of the measured channel whose leakage current is to be collected is connected to the input end of the current collection unit, that is, the leakage current signal of the measured channel whose leakage current is to be collected is obtained by the current collection unit; and the output end of the remaining measured channels being tested is connected to the negative end of the voltage application unit, that is, the voltage at both ends of the measured channel being tested is determined to be a constant voltage source, thereby ensuring that while the leakage current is measured quickly, the normal progress of the HTRB and HTGB tests will not be affected, thereby improving the accuracy of the test results.

[0065] The switch control timing information is determined based on the leakage current acquisition timing of each measured channel.

[0066] The current acquisition unit 2 is used to collect the leakage current signal of the target measured channel when the output end of the target measured channel is connected to the input end of the current acquisition unit, and transmit the leakage current signal to the main control unit; that is, when the output end of the measured channel whose leakage current is to be collected is connected to the input end of the current acquisition unit, the leakage current signal of the "measured channel whose leakage current is to be collected" can be obtained by the current acquisition unit 2, and the leakage current of the other measured channels being tested will not be collected. In this way, it can be ensured that the leakage current signal collected is only the measured channel whose leakage current is to be collected, thereby improving the accuracy of the test results.

[0067] The main control unit 1 is also used to determine whether the target channel under test has a performance fault according to the leakage current signal of the target channel under test. In this solution, the main control unit 1 can determine whether each channel under test has a performance fault such as reliability and stability based on the change trend of the leakage current signal of each channel under test, thereby realizing the reliability and stability screening of each bare die on the SiC wafer.

[0068] In summary, an embodiment of the present application provides a multi-channel leakage current acquisition device, which includes: a main control unit, a current acquisition unit, a voltage application unit, and a switch unit connected to each measured channel; the input end of each measured channel is connected to the positive end of the voltage application unit, the output end of each measured channel is connected to one end of the switch unit corresponding to each measured channel, and the other end of the switch unit corresponding to each measured channel is connected to the negative end of the voltage application unit and the input end of the current acquisition unit; the output end of the current acquisition unit is connected to the input end of the main control unit; the control end of the switch unit corresponding to each measured channel is connected to the output end of the main control unit; the main control unit is used to obtain pre-generated switch control timing information, and control the corresponding connection to the output end of the target measured channel according to the switch control timing information. The on-off state of the target switch unit is controlled so that the output end of the target measured channel is connected to the input end of the current acquisition unit; and the on-off state of the switch unit corresponding to the output end of other measured channels except the target measured channel is controlled so that the output end of other measured channels except the target measured channel is connected to the negative terminal of the voltage application unit; wherein the switch control timing information is used to indicate the open or closed state of the switch unit corresponding to each measured channel at at least one moment; the current acquisition unit is used to collect the leakage current signal of the target measured channel when the output end of the target measured channel is connected to the input end of the current acquisition unit, and transmit the leakage current signal to the main control unit; the main control unit is also used to determine whether the target measured channel has a performance fault according to the leakage current signal of the target measured channel. In the multi-channel leakage current acquisition device provided by the present solution, the core is a current acquisition unit and a switch unit corresponding to each measured channel, and the main control unit controls the on-off state of the switch unit corresponding to each measured channel according to the switch control timing information, so that the current acquisition unit can perform high-precision acquisition of the multi-channel leakage current of the measured wafer without affecting the HTRB and HTGB tests, and at the same time ensure that the test is carried out normally without reducing the test voltage at both ends of the wafer chip, thereby solving the problem that the existing leakage current acquisition solution cannot acquire the leakage current of hundreds or thousands of channels of SiC wafers at a low cost.

[0069] Optionally, refer to Figure 3 As shown, the switch unit corresponding to each tested channel includes: a collection switch and a test switch.

[0070] Exemplarily, the switch unit corresponding to the first measured channel includes: acquisition switch U1 and test switch U2; the switch unit corresponding to the second measured channel includes: acquisition switch U3 and test switch U4; the switch unit corresponding to the nth measured channel includes: acquisition switch 2n-1 and test switch 2n.

[0071] Among them, the output end of the measured channel is connected to one end of the acquisition switch in the switch unit corresponding to the measured channel and one end of the test switch, the other end of the acquisition switch is connected to the input end of the current acquisition unit, and the other end of the test switch is connected to the negative terminal of the voltage application unit. Therefore, by controlling the on and off of the acquisition switch and the test switch, it can be determined whether the output end of the measured channel is connected to the current acquisition unit or the voltage application unit. If it is connected to the current acquisition unit, the leakage current of the measured channel is collected by the current acquisition unit; if it is connected to the voltage application unit, the HTRB and HTGB tests are continued.

[0072] It should be noted that when screening the reliability and stability of each bare die on the SiC wafer, at a certain moment, the acquisition unit of only one channel under test is in the on state, and the acquisition units of the other channels under test are all in the off state, that is, the current acquisition unit only collects the leakage current of one channel under test, so that the collected leakage current can be ensured to be of high accuracy and will not include the leakage current of the channel under test. Therefore, the current acquisition unit can collect the leakage current of each channel under test in turn according to the switch control timing information.

[0073] The main control unit is specifically used for:

[0074] According to the switch control timing information, the test switch in the target switch unit corresponding to the output end of the target measured channel is controlled to be in an open state and the acquisition switch is controlled to be in a closed state; and the acquisition switches in the switch units corresponding to the output ends of other measured channels except the target measured channel are controlled to be in an open state and the test switches are controlled to be in a closed state.

[0075] In this embodiment, the target measured channel is any one of the multiple measured channels, and the main control unit controls the test switch in the target switch unit corresponding to the output end of the target measured channel to be in an open state and the acquisition switch to be in a closed state according to the switch control timing information, that is, the branch connecting the target measured channel to the current acquisition unit is turned on, and the other branch connecting the target measured channel to the voltage application unit is disconnected, so as to realize the collection of the leakage current of the target measured channel; at the same time, the acquisition switch in the switch unit corresponding to the output end of other measured channels except the target measured channel is controlled to be in an open state and the test switch to be in a closed state, that is, the branch connecting the other measured channels to the current acquisition unit is disconnected, and the other branch connecting the other measured channels to the voltage application unit is turned on, so as to realize the normal progress of the HTRB and HTGB tests of other measured channels.

[0076] Optionally, refer to Figure 4 As shown, it is the switch control timing diagram provided by this application.

[0077] Figure 4The switch control timing diagram shown only shows the on-off control timing of the first measured channel, the second measured channel and the nth measured channel.

[0078] The main control unit is specifically used for:

[0079] According to the switch control timing information, the test switch in the switch unit correspondingly connected to the output end of the first measured channel is controlled to remain in an open state from the first moment to the second moment, and the acquisition switch is controlled to be in a closed state from the first moment to the second moment, and the acquisition switches in the switch units correspondingly connected to the output ends of other measured channels except the first measured channel are controlled to be in an open state from the first moment to the second moment, and the test switches are controlled to be in a closed state from the first moment to the second moment, wherein the first moment t0 is earlier than the second moment t1.

[0080] The target measured channel is any one of the multiple measured channels, and the first measured channel is the measured channel that is first in the arrangement order among the multiple measured channels.

[0081] In one possible implementation, the main control unit Figure 4 The switch control timing diagram shown determines that the leakage current of the first channel under test (DUT1) is collected from the first moment to the second moment, that is, t0-t1, that is, the test switch in the switch unit corresponding to the output end of the first channel under test is controlled to be in an open state during the moment t0-t1, and the collection switch is in a closed state during the moment t0-t1, so that the leakage current of the first channel under test (DUT1) flows into the current collection unit, and the current collection unit quickly collects the leakage current of the first channel under test (DUT1).

[0082] And, control the acquisition switch in the switch unit corresponding to the output end of other channels under test except the first channel under test to be in the open state during the time t0-t1 and the test switch to be in the closed state during the time t0-t1, so as to ensure that other channels under test can perform reliability tests normally. After the time t1, the leakage current of the first channel under test (DUT1) is collected, and the collection process of the leakage current of the second channel under test (DUT2) is entered.

[0083] Optionally, specifically for:

[0084] According to the switch control timing information, the test switch in the target switch unit corresponding to the output end of the second measured channel is controlled to be in an open state from the second moment to the third moment, and the acquisition switch is controlled to be in a closed state from the second moment to the third moment, and the acquisition switch in the switch unit corresponding to the output end of other measured channels except the second measured channel is controlled to be in an open state from the second moment to the third moment, and the test switch is controlled to be in a closed state from the second moment to the third moment, wherein the second moment t1 is earlier than the third moment t2.

[0085] The second measured channel is a measured channel that is arranged second in the order of the multiple measured channels.

[0086] In one achievable manner, the main control unit may further continue to Figure 3 The switch control timing diagram shown determines that the leakage current of the second channel under test (DUT2) is collected from the second moment to the third moment, i.e., t1-t2, that is, the test switch in the switch unit corresponding to the output end of the second channel under test is controlled to be in an open state during the moment t1-t2, and the collection switch is controlled to be in a closed state during the moment t1-t2, so that the leakage current of the second channel under test (DUT2) flows into the current collection unit, and the current collection unit quickly collects the leakage current of the second channel under test (DUT2).

[0087] And, control the acquisition switch in the switch unit corresponding to the output end of other channels under test except the second channel under test (DUT2) to be in the open state during the time t1-t2 and the test switch to be in the closed state during the time t1-t2, so as to ensure that other channels under test can perform reliability tests normally. After the time t2, the leakage current of the second channel under test (DUT2) is collected, and the collection process of the leakage current of the next channel under test (DUT2) is entered.

[0088] Optionally, specifically for:

[0089] According to the switch control timing information, the test switch in the target switch unit correspondingly connected to the output end of the nth measured channel is controlled to be in an open state from the n-1th moment to the nth moment, and the acquisition switch is controlled to be in a closed state from the n-1th moment to the nth moment, and the acquisition switches in the switch units correspondingly connected to the output ends of other measured channels except the nth measured channel are controlled to be in an open state from the n-1th moment to the nth moment, and the test switches are controlled to be in a closed state from the n-1th moment to the nth moment, wherein the n-1th moment is earlier than the nth moment.

[0090] The second measured channel is a measured channel that is arranged second in the order of the multiple measured channels.

[0091] In one achievable manner, the main control unit may further continue to Figure 3The switch control timing diagram shown in the figure determines to collect the leakage current of the nth channel under test (DUTn) from the n-1th moment to the nth moment, that is, tn-1-tn, that is, to control the test switch in the switch unit corresponding to the output end of the nth channel under test to be in the open state during the tn-1-tn moment, and the collection switch to be in the closed state during the tn-1-tn moment, so that the leakage current of the nth channel under test (DUTn) flows into the current collection unit, and the current collection unit quickly collects the leakage current of the nth channel under test (DUTn).

[0092] And, control the acquisition switch in the switch unit corresponding to the output end of other channels under test except the nth channel under test (DUTn) to be in the open state within the time tn-1-tn and the test switch to be in the closed state within the time tn-1-tn, so as to ensure that other channels under test can perform reliability tests normally. After the end of the time tn, the leakage current of the nth channel under test (DUTn) is collected, and the above process is repeated to start a new round of leakage current collection, so as to realize the collection of wafer leakage current data in the long-term domain.

[0093] Optionally, the above Figure 2 The acquisition switch in the test circuit includes: a photoelectric relay. Similarly, the test switch may also include: a photoelectric relay. By controlling the on and off of the photoelectric relay, the conduction time of the branch connecting the measured channel and the current sampling unit is shortened, and the leakage current of the measured channel is quickly acquired.

[0094] Optionally, refer to Figure 5 As shown, the current acquisition unit 2 includes: an amplification unit 21 and a acquisition unit 22 .

[0095] The inverting input terminal of the amplifying unit is connected to the other end of the acquisition switch in the switch unit corresponding to each measured channel.

[0096] The positive phase input terminal of the amplifying unit is connected to the negative terminal of the voltage applying unit at the other end of the test switch in the switch unit corresponding to each channel under test.

[0097] The output end of the amplifying unit is connected to the input end of the collecting unit, and the output end of the collecting unit is connected to the input end of the main control unit.

[0098] an amplifying unit, used for acquiring a leakage current signal outputted from an output terminal of a target measured channel, converting the leakage current signal to generate a converted voltage signal, and transmitting the converted voltage signal to an acquisition unit;

[0099] The acquisition unit is used to sample the converted voltage signal, generate a sampled voltage signal, and transmit the sampled voltage signal to the main control unit.

[0100] In one feasible manner, the collected leakage current signal is converted, amplified, and processed by an amplification unit, and the converted voltage signal is sent to a collection unit, which samples the converted voltage signal and transmits the generated sampled voltage signal to a main control unit.

[0101] Optionally, continue to refer to Figure 5 As shown, the amplification unit includes: an amplifier U7 and a first resistor R;

[0102] One end of the first resistor R is connected to the inverting input end of the amplifier U7 and the other end of the acquisition switch in the switch unit corresponding to each measured channel; the other end of the first resistor R is connected to the output end of the amplifier.

[0103] In one possible implementation, taking the leakage current of the first channel under test (DUT1) as an example, continue to refer to Figure 3 As shown, at time t0, the test switch U1 corresponding to the first measured channel (DUT1) is in the open state, the acquisition switch U2 is in the closed state, and the leakage current of the first measured channel (DUT1) flows into the transimpedance amplifier U7, wherein the transimpedance amplifier U7 is an operational amplifier and the first resistor R is a transimpedance. By changing the resistance value of the first resistor R, current acquisition of different ranges can be achieved.

[0104] It should be noted that in the leakage current acquisition solution provided in this application, the principle of "virtual short" of the operational amplifier is used, the level of the positive input terminal and the negative input terminal of the transimpedance amplifier U7 are the same, and the voltage of pin 2 is the same as the ground plane. Therefore, during the leakage current acquisition process, the voltage on both sides of the first measured channel (DUT1) will not change, and the normal reliability test will not be affected while collecting the leakage current.

[0105] Therefore, according to the principle of "virtual disconnection" of the operational amplifier, the leakage current If of the first measured channel (DUT1) flows through the first resistor R. At this time, the leakage current signal can be converted into a voltage signal, that is, I / V conversion, where the voltage V=IF*R.

[0106] Optionally, the resistance value of the first resistor R is determined based on a sampling range of the acquisition unit.

[0107] Optionally, the collection of leakage currents of different ranges can be achieved by changing the resistance value of the first resistor R. For example, taking the range of 0-100nA as an example, a suitable resistor can be selected for conversion. For example, if the first resistor R is 20M ohms, 0-100nA corresponds to a voltage signal of 0-2V.

[0108] Optionally, the main control unit is specifically configured to:

[0109] According to the sampled voltage signal, a leakage current value of the target measured channel is obtained; according to the leakage current value of the target measured channel, it is determined whether the target measured channel has a performance fault.

[0110] Optionally, determining whether the target measured channel has a performance fault according to the leakage current value of the target measured channel includes:

[0111] If the leakage current value of the target measured channel is greater than a preset leakage current threshold, it is determined that the target measured channel has a performance fault.

[0112] In one feasible method, the main control unit compares the leakage current value of each measured channel with the leakage current threshold in turn. If the leakage current value of a measured channel is greater than the leakage current threshold, it is determined that the measured channel has a performance failure, thereby realizing reliability screening of thousands of bare die on SiC wafers and ensuring the accuracy of the screening results.

[0113] To summarize, the multi-channel leakage current acquisition device provided in the present application is based on the switch unit and transimpedance operational amplifier corresponding to each measured channel, and is suitable for a low-cost multi-channel current acquisition circuit for wafer-level reliability testing. It can realize high-precision acquisition of leakage current of hundreds of wafer chips during HTRB and HTGB tests, while ensuring the normal progress of the test without reducing the test voltage at both ends of the wafer chip.

[0114] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0115] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0116] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0117] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (English: processor) to perform some steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (English: Read-Only Memory, referred to as: ROM), random access memory (English: Random Access Memory, referred to as: RAM), disk or optical disk and other media that can store program codes.

Claims

1. A multi-channel leakage current acquisition device, characterized in that: include: A main control unit, a current collection unit, a voltage application unit, and a switch unit correspondingly connected to each measured channel; The input end of each of the measured channels is connected to the positive end of the voltage applying unit, the output end of each of the measured channels is connected to one end of the switch unit corresponding to each of the measured channels, and the other end of the switch unit corresponding to each of the measured channels is connected to the negative end of the voltage applying unit and the input end of the current acquisition unit; The output end of the current collection unit is connected to the input end of the main control unit; The control end of the switch unit corresponding to each of the tested channels is connected to the output end of the main control unit; The main control unit is used to obtain pre-generated switch control timing information, and control the on-off state of the target switch unit corresponding to the output end of the target measured channel according to the switch control timing information, so that the output end of the target measured channel is connected to the input end of the current acquisition unit; and control the on-off state of the switch unit corresponding to the output end of other measured channels except the target measured channel, so that the output end of other measured channels except the target measured channel is connected to the negative terminal of the voltage application unit; wherein the switch control timing information is used to indicate the open or closed state of the switch unit corresponding to each measured channel at at least one moment; The current acquisition unit is used to collect the leakage current signal of the target measured channel when the output end of the target measured channel is connected to the input end of the current acquisition unit, and transmit the leakage current signal to the main control unit; The main control unit is further used to determine whether the target measured channel has a performance fault according to the leakage current signal of the target measured channel; Wherein, the switch unit includes: a collection switch and a test switch; The main control unit is specifically used for: According to the switch control timing information, the test switch in the target switch unit corresponding to the output end of the target measured channel is controlled to be in an open state and the acquisition switch is controlled to be in a closed state; and the acquisition switches in the switch units corresponding to the output ends of other measured channels except the target measured channel are controlled to be in an open state and the test switches are controlled to be in a closed state.

2. The device according to claim 1, characterized in that The main control unit is specifically used for: According to the switch control timing information, the test switch in the switch unit corresponding to the output end of the first measured channel is controlled to be in an open state from the first moment to the second moment, and the acquisition switch is controlled to be in a closed state from the first moment to the second moment, and the acquisition switch in the switch unit corresponding to the output ends of other measured channels except the first measured channel is controlled to be in an open state from the first moment to the second moment, and the test switch is controlled to be in a closed state from the first moment to the second moment, wherein the first moment is earlier than the second moment.

3. The device according to claim 1, characterized in that The main control unit is specifically used for: According to the switch control timing information, the test switch in the target switch unit corresponding to the output end of the second measured channel is controlled to remain in an open state from the second moment to a third moment, and the acquisition switch is controlled to be in a closed state from the second moment to the third moment, and the acquisition switches in the switch units corresponding to the output ends of other measured channels except the second measured channel are controlled to be in an open state from the second moment to the third moment, and the test switches are controlled to be in a closed state from the second moment to the third moment, wherein the second moment is earlier than the third moment.

4. The device according to claim 1, characterized in that The acquisition switch includes: a photoelectric relay.

5. The device according to claim 1, characterized in that The current collection unit includes: an amplification unit and a collection unit; The inverting input end of the amplifying unit is connected to the other end of the acquisition switch in the switch unit corresponding to each of the measured channels; The positive phase input terminal of the amplifying unit is connected to the negative terminal of the voltage applying unit which is the other end of the test switch in the switch unit corresponding to each of the channels under test; The output end of the amplifying unit is connected to the input end of the collecting unit, and the output end of the collecting unit is connected to the input end of the main control unit; The amplifying unit is used to obtain a leakage current signal outputted from the output end of the target measured channel, convert the leakage current signal to generate a converted voltage signal, and transmit the converted voltage signal to the acquisition unit; The acquisition unit is used to sample the converted voltage signal, generate a sampled voltage signal, and transmit the sampled voltage signal to the main control unit.

6. The device according to claim 5, characterized in that The amplification unit comprises: an amplifier and a first resistor; One end of the first resistor is connected to the inverting input end of the amplifier and the other end of the acquisition switch in the switch unit corresponding to each of the measured channels; the other end of the first resistor is connected to the output end of the amplifier.

7. The device according to claim 6, characterized in that The resistance value of the first resistor is determined based on the sampling range of the acquisition unit.

8. The device according to claim 5, characterized in that The main control unit is specifically used for: Obtaining a leakage current value of the target measured channel according to the sampled voltage signal; It is determined whether the target measured channel has a performance fault according to the leakage current value of the target measured channel.

9. The device according to claim 8, characterized in that The determining, according to the leakage current value of the target measured channel, whether the target measured channel has a performance fault includes: If the leakage current value of the target measured channel is greater than a preset leakage current threshold, it is determined that the target measured channel has a performance fault.

Images