System, electronic device and storage medium for array device continuous testing

Abstract

The application provides a system, electronic equipment and storage medium for continuous testing of array devices, comprising a first host computer and a probe station; the first host computer sends a scanning path to the probe station to control the probe station to perform scanning test on a to-be-tested array device; a tray of the probe station moves according to path points set by the scanning path, reaches a specified position, then moves the tray upward to connect a probe and an electrode of the to-be-tested array device, and the to-be-tested array device is tested by an electronic testing device according to a test instruction sent by a second host computer, and the above process is repeated until all electrodes of the to-be-tested array device are tested. Scanning test of any test parameter can be realized on any array device, and then data visualization is performed in combination with a detection position coordinate and a test result of the position, thereby providing comprehensive and effective test data for array devices of different shapes.

Description

Technical Field

[0001] This invention relates to the field of device testing technology, and more specifically to a system, electronic device, and storage medium for continuous testing of array devices. Background Technology

[0002] In array device testing, the main technology involves modeling the array shape to control the connection of probes to devices at different locations, thereby completing batch testing. Since multiple chips are distributed on a wafer, and multiple devices are distributed on each chip, if the chips on the wafer or the devices on the chip are not perfectly aligned during the design phase, the spacing step size of each device becomes variable and difficult to model. This can certainly be solved by editing nested scan paths; however, in this mode, the complexity of summarizing and processing the test results of the entire array device increases significantly. Summary of the Invention

[0003] This invention proposes a system, electronic device, and storage medium for continuous testing of array devices, in order to solve the technical problems of existing device testing methods, which are complex in setting up test modes and have high complexity in summarizing test results when facing arrays with incomplete and irregular alignment.

[0004] To address the aforementioned technical problems, this invention provides a system for continuous testing of array devices, comprising a first host computer and a probe station;

[0005] The first host computer sends a scanning path to the probe station and controls the probe station to scan and test the array device under test. The tray of the probe station moves according to the path points set by the scanning path. After reaching the designated position, the tray moves up to connect the probe with the electrode of the array device under test. The electronic testing equipment tests the array device under test according to the test instructions sent by the second host computer. The above process is repeated until all electrodes of the array device under test have been tested.

[0006] Preferably, the first host computer controls the movement of the probe station's tray in all directions using the script execution environment and communication instruction set provided by the probe station.

[0007] Preferably, the first host computer and the second host computer communicate through control logs.

[0008] Preferably, when the probe station scans and tests the array device under test, it imports or creates a two-dimensional scan path from the library of the first host computer; the tray control unit of the first host computer generates a control instruction set according to the scan path and sends a movement instruction to the probe station; after the probe station controls the tray to complete the instruction, it feeds back the position information to the first host computer, and the first host computer writes the position information into the control log; after the device control unit of the second host computer detects the log update, it controls the electronic test equipment to perform the test according to the set test parameters; the test result is combined with the position information to complete the data summary, and a "complete" signal is fed back to the control log to proceed to the next position for testing; after the tray control unit of the first host computer detects the "complete" signal, it issues the next instruction to enter the next position, i.e., the next device for testing; this process is repeated until all instructions in the control instruction set are completed, which is to complete the scan test of the preset array.

[0009] Preferably, during the entire test process, the second host computer summarizes and presents all test data, and saves the data after the test is completely completed.

[0010] Preferably, the scanning path includes: a minimum repeating unit scanning path and a two-dimensional path scanning path;

[0011] The minimum repeating unit scan path is used for array devices with incomplete periodic arrangement;

[0012] The two-dimensional scanning path is used to improve the accuracy of the alignment between the probe and the device under test through a displacement compensation algorithm;

[0013] The two-dimensional scanning path is compatible with one-dimensional scanning.

[0014] Preferably, the displacement compensation algorithm corrects for deviations in device spacing caused by plastic deformation of the wafer containing the array devices by setting an offset value.

[0015] Preferably, the minimum repeating unit scan path includes a nine-grid minimum unit, wherein the minimum unit of the nine-grid is Ux; Uy; unit; center_x = 0; center_y = 0; relative_points = [(0,0),(-unit,0),(-2*unit,0),(0,unit),(-unit+100,unit),(-2*unit-135,unit),(0,2*unit),(-unit,2*unit),(-2*unit,2*unit)], where Ux represents the length of this nine-grid in the x-direction; Uy represents the length of this nine-grid in the y-direction; unit represents the distance between each device within the nine-grid, all in micrometers; center_x and center_y represent the center point position of the starting reference test device; +100 and -135 represent the relative offset of the corresponding device.

[0016] The present invention also provides an electronic device, comprising: a memory, a processor, and a computer program, wherein the computer program is stored in the memory and configured to be executed by the processor to implement the system described above.

[0017] The present invention also provides a computer-readable storage medium storing a computer program that is executed by a processor to implement the system described above.

[0018] The beneficial effects of this invention include at least the following: In the continuous testing system for array devices provided in this embodiment, the first and second host computers can coordinate with each other to use an automatic probe station and electronic testing equipment to continuously scan and test the array device under test, generating test results. The second host computer can also obtain the detection position of the device under test through control logs, correlate the test results at each position with its corresponding position, mark the results (good or bad) with different colors, and save them to an Excel file. Therefore, this solution can perform scanning tests on any array device with arbitrary test parameters, and then combine the detection position coordinates and the test results at that position for data visualization, providing comprehensive and effective test data for array devices of different shapes. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the implementation process of the system according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the system structure connection according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the internal communication structure of the system according to an embodiment of the present invention;

[0022] Figure 4This is a schematic diagram of an array device and its smallest repeating unit according to an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the results of a scanning test of an array device provided in an embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of an intermediate process for scanning and testing an array device, provided as an embodiment of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0026] like Figure 1 As shown, this embodiment of the invention provides a system for continuous testing of array devices, including a first host computer and a probe station.

[0027] The first host computer sends the scanning path to the probe station and controls the probe station to scan and test the array device under test. The probe station tray moves according to the path points set in the scanning path. After reaching the designated position, the tray moves up to connect the probe with the electrode of the array device under test. The electronic testing equipment tests the array device under test according to the test instructions sent by the second host computer. The above process is repeated until all electrodes of the array device under test have been tested.

[0028] Specifically, the system structure connections are as follows: Figure 2 As shown, it includes a first host computer, a second host computer, a probe station, and electronic testing equipment; the probe station and the electronic testing equipment are connected, the probe station and the first host computer are connected, the electronic testing equipment and the second host computer are connected, and the first host computer and the second host computer are connected.

[0029] like Figure 3As shown, each result in the system includes the units and control directions. Specifically, a two-dimensional scanning path is imported or created from the library of the first host computer. The tray control unit on it generates a control instruction set according to the scanning path and sends an instruction to the tray of the probe station. After the tray completes the instruction, it feeds back the position information, and the tray control unit writes the position information into the control log. After the device control unit on the second host computer detects the update of the control log, it controls the electronic test equipment to perform the test according to the pre-set test parameters. The test results are stored and visualized in combination with the position information. At the same time, a "complete" signal is fed back to the control log to proceed to the next position for testing. After the tray control unit detects the "complete" signal, it sends the next instruction to enter the next position, i.e., the next device for testing. This process is repeated until all instructions in the control instruction set are completed, which is to complete the scanning test of the preset array.

[0030] In this embodiment, the first host computer is any computer device equipped with a communication protocol or software with the probe station. It uses the script running environment provided by the probe station product manufacturer and the communication instruction set provided in the instruction manual to control the movement of the tray part in the probe station up, down, left, and right.

[0031] Since the probes on the probe station are connected to the electronic testing equipment, it is often difficult to move the probes as a whole. Therefore, in this embodiment, the probes are kept stationary while the tray below moves in the opposite direction to traverse the array devices.

[0032] The first host computer is equipped with a library of scan paths for storing different scan paths, which is convenient for secondary use by testers. When considering the diversity of scan paths, a method of superimposing scan paths into the smallest repeatable unit is specifically adopted to increase the adaptability of the program. That is to say, the final scan path can be a path nested within a path.

[0033] This invention uses a schematic diagram of an array device and its smallest repeating unit as an example for illustration. Figure 4As shown, its smallest repeating unit is a square grid of nine devices. However, the electrodes are not all in the same position on the devices, meaning that a series of scan tests cannot be completed by simple linear repetition. In this case, it is necessary to model the grid as the smallest repeating unit and combine it with the scan path of the array devices to complete the matching. The grid model is as follows: Ux = 20000; Uy = 20005; unit = 6666; center_x = 0; center_y = 0; relative_points = [(0,0),(-unit,0),(-2*unit,0),(0,unit),(-unit+100,unit),(-2*unit-135,unit),(0,2*unit),(-unit,2*unit),(-2*unit,2*unit)].

[0034] Where Ux = 20000 represents the length of this 3x3 grid in the x direction; Uy = 20005 represents the length of this 3x3 grid in the y direction; unit = 6666 represents the distance between each device in the 3x3 grid, all in micrometers; center_x and center_y indicate the center point position setting of the starting reference test device in the upper left corner.

[0035] The relative positions of the other eight devices are determined relative to the reference device. It's worth noting that this scan proceeds from the top left corner to the bottom right corner of the wafer, resulting in an x-coordinate of -unit in the positional equation. This is because the tray needs to move the wafer along it in the negative direction. The scan path is generated by setting the indentation per line and the number of 3x3 grids per line, such as inputting parameters (2,3), (1,5), (0,7), (1,5), (1,5), (2,3). Figure 4 The array device scan path is shown, where (2,3) represents the repeating unit in the first row, indented by two, and then includes three repeating units. The generated scan points are positions1 = [(0,0),(-1,0),(-2,0),(1,1),(0,1),(-1,1),(-2,1),(-3,1),(2,2),(1,2),(0,2),(-1,2),(-2,2),(-3,2),(-4,2),(1,3),(0,3),(-1,3),(-2,3),(-3,3),(1,4),(0,4),(-1,4),(-2,4),(-3,4),(0,5),(-1,5),(-2,5)].

[0036] It's worth mentioning that if the user inputs parameters (12,3), (11,4), (10,5), (11,4), (11,4), (12,3), the program will still generate the same scan points positions1. This is because the scan points record the relative positions, and increasing the first-line indentation does not affect the relative relationship. However, if the user slices the wafer, for example, by removing the two right columns, thus changing the shape of the array under test, then new parameters (2,3), (1,4), (0,5), (1,4), (1,4), (2,3) need to be input. The generated scan points positions2 = [(0,0),(-1,0),(-2,0),(1,1),(0,1),(-1,1),(-2,1),(2,2),(1,2),(0,2),(-1,2),(-2,2),(1,3),(0,3),(-1,3),(-2,3),(1,4),(0,4),(-1,4),(-2,4),(0,5),(-1,5),(-2,5)].

[0037] These scan paths can be saved to the scan path library for easy reuse next time. The naming of "positions" is based on user preference. Each point in positions1 and position2 corresponds to a minimum repeating unit, i.e., a 3x3 grid. Therefore, when the 23 points in positions1 are completed, the scan test of the entire array of 23*9=207 devices is completed. If the array shape to be scanned is more irregular, the scan points can be described by directly editing "positions" instead of generating them by inputting parameters. The coordinates in "positions" can be decimals. When moving between devices in different positions, the tray control program will first lower the tray by 500um before moving it. After reaching the corresponding position, it will rise by 500um to re-engage the probe with the device electrode. This protects both the probe and the device from damage.

[0038] Upon reaching the location of each new device, the tray control unit sends a message to the control log: 'TestPython logging to Velox({},{})'.format(position_number,relation_number). The values ​​of position_number and relation_number are determined by specific values, where position_number < 23 and relation_number < 9. For example, Test Python logging to Velox(15,4) means the 4th device in the 15th 3x3 grid. The aforementioned two-dimensional scanning fully compatible with the one-dimensional case means that simply setting relative_points = [(0,0)] and then setting the input parameters to (0,128) is sufficient to complete the scanning test of a row of 128 devices.

[0039] Each device has an electrode that is a square with sides of 80µm. If the probe's predetermined position is set at the center of the electrode, the allowable error is ±40µm. For better contact between the probe and the electrode, the probe must not exceed ±20µm from the electrode's center point. The minimum displacement distance of the probe tray on the probe stage is 4µm, which is theoretically sufficient to complete the task. However, since the side length of the 9x9 grid is 20000µm, and the displacement of the furthest 9x9 grid is (-40000, 100000), even a slight deformation of the wafer can lead to significant errors in determining the position of the last device—the allowable deformation in the y-direction is limited. Meanwhile, since it is a two-dimensional scan, the resulting errors are cumulative, which further amplifies the uncertainties. Therefore, displacement compensation algorithms for different deformations have emerged. The displacement offset cases considered in the program include: in-plane displacement offset caused by wafer bumps and the non-orthogonality problem in the x and y directions caused by wafer fabrication. In-plane displacement offset caused by wafer bumps refers to the situation where, during production or use, two points lum apart in a plane will deviate from their original plane due to slight convexity of the wafer. In this case, the distance between the two points is often slightly less than lum, and the specific value depends on the degree of bumps. The non-orthogonality problem in the x and y directions caused by wafer fabrication is also a problem unique to two-dimensional scanning. It refers to the fact that when devices are aligned in the x direction, the connecting lines of devices in the same column are not perpendicular to this x direction. In this embodiment, the angle between the x and y directions of the wafer is slightly greater than 90 degrees, so when the tray is moved in the positive y-axis direction, the next device will appear to the left of the expected position. Since this error value is proportional to the displacement in the direction and the error ratio of wafers in the same batch is the same, it can be ruled out as a random error.

[0040] In this embodiment, the displacement compensation algorithm includes a pre-scan before the formal scan. This pre-scan is performed with the light on and only scans the first device in each 3x3 grid. Therefore, its step size is 20000µm. At each new position, image information from the microscope is read, and the device's displacement is recorded as δx and δy by comparing its offset with the first image using BFMatcher feature matching. All 23 δx and δy values ​​are stored in the same array. During the formal scan, the tray displacement is increased by adding δx and δy to x*20000µm and y*20000µm to ensure the probe is at the relative center of the electrode. The compensation amounts for the other eight devices in each 3x3 grid are considered the same as the first device and are not individually calibrated to save time.

[0041] Having achieved precise alignment, a second host computer is needed to perform various parameter tests and data processing at that location. This embodiment uses a Keithley 2636B source test unit as the electronic testing device, which connects to the second host computer via USB. However, other connection methods can achieve the same effect with simple modifications. It's important to note that the program in the second host computer only requires minor modifications to perform tests on other electronic devices controllable by host computer commands. Before the device control unit on the second host computer, there are some initialization steps. During program execution, a pop-up window will ask the user where to save the test data for later viewing.

[0042] This embodiment uses the 2636B to test the reverse bias dark current of Si-based PIN devices. The device address needs to be provided; in this embodiment, `instrument_address = "USB0::0x05E6::0x2636::4544659::INSTR"`. This address is unique and fixed for each device. Then, attempt to open communication with the device: `instrument = rm.open_resource(instrument_address); instrument.timeout = 10000; print("Instrument opened successfully!"). The device timeout is set to 10000ms (10s) because the 2636 source meter requires a longer testing time when testing weak currents. Without manually increasing the timeout, frequent errors and inability to read data will occur. It should be noted that the timeout refers to the maximum waiting time, not the time required to test each data point. The test parameters are set using an enumeration method: voltages = [-30, -60, -90, -120, -150, -180, 2]. The test parameters can be modified arbitrarily, such as reducing the step size, but this will increase the test time. They can also be expressed analytically, such as for voltage in range(2, -181, -2), which means a step size of -2V from 2V to -180V. The program performs the following operations for each voltage test point: `instrument.write(f"smua.source.levelv={voltage}");` and `instrument.write("printnumber(smua.measure.iv())")` writes the voltage to the 2636 and inputs the actual voltage and current to the communication unit. Then, it reads this data to the second host computer via `response = instrument.read()` and displays `print(f"Voltage:{voltage}V,RealVoltage:{realvoltage}V,Current:{current}A")` in the program's interactive window to allow the user to quickly determine if the data is reasonable. Since the test environment needs to be in a dark setting, the "2V" is used to determine if the device is functioning correctly and if the probes are making good contact with the electrodes. Often, the actual voltage will not reach 2V. This is because the device's on-state current is higher than the current limit set by the 2636 source meter, so the source meter increases its internal resistance to reduce the current to the limit. This also divides the total 2V voltage, resulting in a measured voltage across the device that is less than 2V.After the set voltage test is completed, the storage unit in the second host computer uses the `def check_file(shared_file_path)` function, combined with the location information "Test Python logging to Velox(15,4)" read from the control log, to associate the test data with (15,4) and save it to an Excel file named `measure_15_4.xlsx`. In the data visualization part, simply modify the required feature value, such as setting `specific_row = df[df['Voltage(V)'] == voltage_value]` to `voltage_value = -180`. The program will then index the required row, extract the corresponding current test result and the device's position data in the entire array, and then output the current test results of all devices at -180V and their corresponding positions to a new Excel file, annotated with color gradients as shown below. Figure 5 The results are shown. Figure 6 The image shows a real-time summary of the results captured at random moments during the actual test, thus completing the entire testing process for the array device.

[0043] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described; only preferred embodiments of the present invention are illustrated. The descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. As long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0044] It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the appended claims.

Claims

1. A system for continuous testing of array devices, characterized in that: Including the first host computer and the probe station; The first host computer sends a scanning path to the probe station and controls the probe station to scan and test the array device under test: the tray of the probe station moves according to the path points set by the scanning path. After reaching the designated position, the tray moves up to connect the probe with the electrode of the array device under test. The electronic testing equipment tests the array device under test according to the test instructions sent by the second host computer. The above process is repeated until all electrodes of the array device under test are tested. The first and second host computers communicate through control logs. When the probe station scans and tests the array device under test, it imports or creates a two-dimensional scan path from the library of the first host computer. The tray control unit of the first host computer generates a control instruction set according to the scan path and sends a movement command to the probe station. After the probe station controls the tray to complete the command, it feeds back the position information to the first host computer, which writes the position information into the control log. After the device control unit of the second host computer detects the log update, it controls the electronic test equipment to perform the test according to the set test parameters. The test results are combined with the position information to complete the data summary, and a "complete" signal is fed back to the control log to proceed to the next position for testing. After the tray control unit of the first host computer detects the "complete" signal, it issues the next command to enter the next position, i.e., the next device for testing. This process is repeated until all commands in the control instruction set are completed, which is to complete the scan test of the preset array.

2. The system for continuous testing of array devices according to claim 1, characterized in that: The first host computer controls the movement of the probe station's tray in all directions using the script execution environment and communication instruction set provided by the probe station.

3. The system for continuous testing of array devices according to claim 1, characterized in that: Throughout the testing process, the second host computer aggregates all test data, presents the data, and saves it after the test is completely completed.

4. The system for continuous testing of array devices according to claim 1, characterized in that: The scanning path includes: the minimum repeating unit scanning path and the two-dimensional scanning path; The minimum repeating unit scan path is used for array devices with incomplete periodic arrangement; The two-dimensional scanning path is used to improve the accuracy of the alignment between the probe and the device under test through a displacement compensation algorithm; The two-dimensional scanning path is compatible with one-dimensional scanning. The displacement compensation algorithm corrects for deviations in device spacing caused by plastic deformation of the wafer containing the array devices by setting an offset value. The minimum repeating unit scan path includes a nine-grid minimum unit, which is defined as Ux; Uy; unit; center_x=0; center_y=0; relative_points=[(0,0),(-unit,0),(-2*unit,0),(0,unit),(-unit+100,unit),(-2*unit-135,unit),(0,2*unit),(-unit,2*unit),(-2*unit,2*unit)], where Ux represents the length of this nine-grid in the x-direction; Uy represents the length of this nine-grid in the y-direction; unit represents the distance between each device within the nine-grid, all in micrometers; center_x and center_y represent the center point position of the initial reference test device; +100 and -135 represent the relative offset of the corresponding device.

5. An electronic device, comprising: A memory, a processor, and a computer program, characterized in that: the computer program is stored in the memory and configured to be executed by the processor to implement the system according to any one of claims 1 to 4.

6. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program that is executed by a processor to implement the system according to any one of claims 1 to 4.

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