A method of calibrating a wafer test system

Abstract

The application discloses a kind of wafer test system calibration methods, the calibration method includes electrical parameter calibration and displacement parameter calibration, wherein, electrical parameter calibration method is: to the test machine in wafer test system sends standard source control signal, and gathers the first electric signal that test machine issues and is transferred to probe card, and the second electric signal that probe card detects and is returned to test machine;First and second electric signal corresponding with pre-set electric signal are compared, to realize the integrity calibration of wafer test system test machine electrical parameter;Displacement parameter calibration method is: to probe station sends displacement signal, simultaneously obtains the displacement information of probe station measured using laser interferometer, the displacement information is compared with pre-set displacement value, to realize the calibration of wafer test system displacement.The application can realize the calibration of electrical parameter and non-electrical parameter of wafer test system simultaneously, effectively improve the test accuracy and reliability of wafer test system.

Description

Technical Field

[0001] This invention belongs to the technical field of wafer testing systems, and more specifically, relates to a calibration method for a wafer testing system. Background Technology

[0002] A wafer testing system consists of a tester, probe station, wafer carrier, and probe cards. During testing, the wafer under test is placed on the wafer carrier. The probe station is used to adjust the horizontal and vertical position of the wafer carrier so that the test key pads on the wafer under test contact the probes on the probe cards, thereby achieving the corresponding electrical measurements. The tester is used to provide signal excitation and measurement during the testing process. Therefore, the performance of the probe station and the integrated circuit testing system directly affects the test results of the wafer. Consequently, the wafer testing system needs to be calibrated regularly during use to ensure it meets testing requirements.

[0003] Currently, the calibration of wafer testing systems only measures the testing machine within the system, neglecting to measure the connecting parts such as probe cards. This ignores the impact of these parts on the wafer testing results, increasing the risk of false detections and missed detections during the wafer testing process. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a calibration method for a wafer testing system that can simultaneously calibrate the electrical and non-electrical parameters of the wafer testing system, effectively improving the testing accuracy and reliability of the wafer testing system.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a calibration method for a wafer testing system, applied to a wafer testing system calibration apparatus. The wafer testing system includes a tester, a probe station, a wafer stage, and probe cards. The calibration method includes electrical parameter calibration and displacement parameter calibration, wherein...

[0006] The calibration method for the electrical parameters is as follows: a standard source control signal is sent to the tester in the wafer testing system, and a first electrical signal transmitted from the tester to the probe card via an adapter and a second electrical signal detected and transmitted back to the tester by the probe card are collected; the first electrical signal is compared with the electrical signal set by the tester, and the second electrical signal is compared with the preset electrical signal, thereby achieving complete calibration of the electrical parameters of the tester in the wafer testing system;

[0007] The calibration method for the displacement parameter calibration is as follows: X-axis and Y-axis displacement signals are sent to the probe station at preset time intervals, and the displacement information of the probe station measured by the laser interferometer is acquired at the same time; then the displacement information acquired under different signals is compared with the preset displacement value, thereby realizing the calibration of the X-axis and Y-axis displacement of the wafer testing system; wherein, the reflector in the laser interferometer is mounted on the probe station.

[0008] In one embodiment, during electrical parameter calibration, the wafer testing system calibration device and the tester in the wafer testing system transmit signals through a calibration interface board, which is set on the wafer support stage.

[0009] The calibration interface board is provided with a number of contact PADs. The number and distribution of the contact PADs are set according to the number and distribution of probes in the probe card. The calibration interface board is also provided with an SMA interface, which is electrically connected to the contact PADs.

[0010] In one embodiment, the SMA interface and several contact pads are all disposed on the upper surface of the calibration interface board.

[0011] In one embodiment, the wafer testing system is equipped with a temperature sensor and a temperature control component on the wafer stage;

[0012] The calibration method further includes temperature calibration, which involves sending cooling and heating signals to the temperature control component at intervals while acquiring temperature information detected by the temperature sensor; then comparing the temperature information acquired under different signals with a preset temperature value to calibrate the temperature parameters of the wafer testing system.

[0013] In one embodiment, the temperature sensor is a flexible PT100 temperature sensor.

[0014] In one embodiment, the wafer testing system calibration device includes:

[0015] The wafer testing system calibration device includes:

[0016] The electrical parameter calibration module is used to send a standard source control signal to the tester in the wafer testing system, and to collect the first electrical signal transmitted from the tester to the probe card via an adapter, and the second electrical signal detected by the probe card and transmitted back to the tester; the first electrical signal is compared with the electrical signal set by the tester, and the second electrical signal is compared with the preset electrical signal, thereby realizing the integrity calibration of the electrical parameters of the wafer testing system;

[0017] The displacement parameter calibration module is used to send X-axis and Y-axis displacement signals to the probe station at preset time intervals, and at the same time acquire the displacement information of the probe station measured by the laser interferometer. The displacement information acquired under different signals is compared with the preset displacement values ​​to achieve calibration of the X-axis and Y-axis displacement of the wafer testing system; wherein, the reflector in the laser interferometer is mounted on the probe station.

[0018] In one embodiment, the wafer testing system is provided with a temperature sensor and a temperature control component on the wafer stage; the wafer testing system calibration device includes a temperature parameter calibration module;

[0019] The temperature parameter calibration module is used to send cooling and heating signals to the temperature control component at intervals, and at the same time acquire the temperature information detected by the temperature sensor; then, it compares the temperature information acquired under different signals with the preset temperature value to achieve calibration of the temperature parameters of the wafer testing system.

[0020] Secondly, the present invention provides a calibration method for a wafer testing system, applied to a wafer testing system calibration device and a host computer. The wafer testing system includes a tester, a probe station, a wafer carrier, and probe cards. The calibration method includes the following steps:

[0021] (1) Establish network communication between the wafer test system calibration device and the host computer, and send a self-test signal to the wafer test system calibration device through the host computer so that the wafer test system calibration device can complete the self-test operation.

[0022] (2) The host computer controls the wafer testing system calibration device to send a standard source control signal to the test machine in the wafer testing system. The wafer testing system calibration device collects the first electrical signal sent by the test machine and transmitted to the probe card through the adapter, and the second electrical signal detected by the probe card and transmitted back to the test machine. The first electrical signal is compared with the electrical signal set by the test machine, and the second electrical signal is compared with the preset electrical signal, thereby realizing the integrity calibration of the electrical parameters of the test machine in the wafer testing system. At the same time, the electrical parameter calibration data is transmitted back to the host computer.

[0023] (3) The upper computer controls the wafer testing system calibration device to send X-axis and Y-axis displacement signals to the probe station at preset time intervals. The wafer testing system calibration device obtains the displacement information of the probe station measured by the laser interferometer. Then, the displacement information obtained under different signals is compared with the preset displacement value to realize the calibration of the X-axis and Y-axis displacement of the wafer testing system. At the same time, the displacement parameter calibration data is sent back to the upper computer. The reflector in the laser interferometer is installed on the probe station.

[0024] In one embodiment, the host computer is used to process the electrical parameter calibration data and temperature calibration data according to the user's operation instructions and then generate a calibration report.

[0025] Compared to traditional wafer testing system calibration, the calibration method for a wafer testing system provided by this invention includes not only calibrating the test electromechanical parameter source module in the wafer testing system, but also calibrating the test electromechanical parameter table module in the wafer testing system, enabling complete calibration of the electrical parameters of the wafer testing system. In addition, a laser interferometer is used to calibrate the displacement parameters of the displacement stage in the wafer testing system, which can effectively ensure high-precision alignment between the probes in the probe card and the wafer under test, thereby effectively improving the accuracy and reliability of the test results of the wafer testing system. Attached Figure Description

[0026] Figure 1 This is a schematic flowchart of a calibration method for a wafer testing system provided in an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram illustrating the principle of calibrating displacement parameters according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of an interface device provided in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram illustrating the principle of calibrating temperature parameters according to an embodiment of the present invention;

[0030] Figure 5 This is a block diagram of a calibration device for a wafer testing system provided in an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0032] It should be noted that a traditional wafer testing system mainly consists of a tester, a probe station, a wafer carrier, and a probe card. The wafer under test (DUT) is placed on the wafer carrier. The probe station is used to adjust the horizontal and vertical position of the wafer carrier so that the test key pads on the DUT contact the probes on the probe card, thereby achieving the corresponding electrical measurements. The tester internally includes an electrical parameter source module, an electrical parameter meter module, and a judgment module. The electrical parameter source module sends an excitation signal to the probe card, which is transmitted to the DUT via the probes on the probe card. The signal output by the DUT is then transmitted back via the probes on the probe card and stored in the electrical parameter meter module within the tester. The judgment module within the tester then uses these signals to determine whether the DUT has defects.

[0033] To address the problem that traditional wafer testing system calibration only measures the testing machine within the system, affecting the transmission and traceability of key parameters during wafer testing and resulting in low accuracy and reliability of test results, this invention provides a calibration method for a wafer testing system. This calibration method is implemented using a wafer testing system calibration device, such as... Figure 1 As shown, the calibration method includes electrical parameter calibration and non-electrical parameter calibration.

[0034] The calibration method for electrical parameter calibration is as follows: (1) Send a standard source control signal to the tester in the wafer test system, and collect the first electrical signal transmitted to the probe card via the adapter and the second electrical signal detected and transmitted back to the tester by the probe card; (2) Compare the first electrical signal with the electrical signal set by the tester. When the comparison result is outside the preset comparison value range, calibrate the electrical parameter source module in the tester, thereby calibrating the electrical parameter source module of the tester in the wafer test system; at the same time, compare the second electrical signal with the preset electrical signal. When the comparison result is outside the preset comparison value range, calibrate the electrical parameter table module in the tester, thereby calibrating the electrical parameter table module of the tester in the wafer test system, thereby achieving the integrity calibration of the electrical parameters of the tester in the wafer test system.

[0035] Since accurate micro-displacement of the probe stage is fundamental to ensuring high-precision alignment between the probe and the die, the non-electrical parameter calibration provided in this embodiment includes displacement parameter calibration, which is achieved using a laser interferometer, such as... Figure 2 As shown, the displacement parameters of the wafer testing system are calibrated by fixing the reflector in the laser interferometer to the probe stage of the wafer testing system.

[0036] Specifically, the calibration method for the displacement parameter calibration is as follows: (1) Send X-axis and Y-axis displacement signals to the probe station at a preset time interval, and at the same time acquire the displacement information of the probe station measured by the laser interferometer; (2) Then compare the displacement information acquired under different signals with the preset displacement value. When the comparison result is outside the preset comparison value range, the displacement stage in the wafer testing system is calibrated, thereby realizing the calibration of the X-axis and Y-axis displacement of the wafer testing system.

[0037] Furthermore, considering the diverse types of testers in wafer testing systems, different interface devices are required for connecting different testers to the wafer testing system calibration device, resulting in poor versatility. Therefore, this embodiment provides a highly versatile interface device that can flexibly connect the calibration device to wafer testing systems of various tester models.

[0038] Specifically, such as Figure 3 As shown, the interface device provided in this embodiment is a standard interface board. When calibrating the wafer testing system, this standard interface board is placed on the wafer support stage. The calibration interface board has several contact pads, the number and distribution of which are set according to the number and distribution of probes in the probe card, thereby improving the universality of the wafer testing system calibration device. Simultaneously, the calibration interface board also has an SMA interface, which is electrically connected to the contact pads. Electrical signals are input and output via the coaxial SMA interface, effectively reducing signal loss during transmission. Preferably, the SMA interface and the contact pads can be located on the upper surface of the calibration interface board to ensure that the wafer support stage is not damaged during the wafer testing system calibration process.

[0039] Compared to traditional wafer testing system calibration, the calibration method provided in this embodiment includes not only calibrating the test electromechanical parameter source module in the wafer testing system, but also calibrating the test electromechanical parameter table module in the wafer testing system, enabling complete calibration of the electrical parameters of the wafer testing system. In addition, a laser interferometer is used to calibrate the displacement parameters of the displacement stage in the wafer testing system, which can effectively ensure high-precision alignment between the probes in the probe card and the wafer under test, thereby effectively improving the accuracy and reliability of the test results of the wafer testing system.

[0040] In one embodiment, considering that thermoelectric potential and noise are generated at the test bond pads of the wafer under test at high temperatures, which can easily interfere with the test results of the wafer testing system and affect the accuracy of the test results, the following measures are taken: Figure 4 As shown, this embodiment adds a temperature sensor and a temperature adjustment component to the wafer testing system's substrate. The temperature sensor can be a flexible PT100 temperature sensor, attached to the substrate; the temperature adjustment component can be a commonly used heating and cooling component in the art.

[0041] Accordingly, the non-electrical parameter calibration provided in this embodiment also includes temperature calibration. The calibration method for temperature calibration is as follows: (1) sending cooling and heating signals to the temperature control component at intervals, and simultaneously acquiring the temperature information detected by the temperature sensor; (2) comparing the temperature information acquired under different signals with the preset temperature value. When the comparison result is outside the preset comparison value range, the temperature control component in the wafer testing system is calibrated, thereby realizing the calibration of the temperature parameters of the heating and cooling components in the wafer testing system.

[0042] Figure 2 This is a schematic diagram of the structure of a wafer testing system calibration device provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the wafer testing system calibration device provided in this embodiment includes an electrical parameter calibration module and a displacement parameter calibration module.

[0043] The electrical parameter calibration module is used to send a standard source control signal to the tester in the wafer testing system, and to collect the first electrical signal transmitted from the tester to the probe card via the adapter, and the second electrical signal detected by the probe card and transmitted back to the tester; the first electrical signal is compared with the electrical signal set by the tester, and the second electrical signal is compared with the preset electrical signal, thereby realizing the integrity calibration of the electrical parameters of the tester in the wafer testing system.

[0044] The displacement parameter calibration module sends X-axis and Y-axis displacement signals to the probe station at preset time intervals, while simultaneously acquiring the displacement information of the probe station measured by a laser interferometer. It then compares the displacement information acquired under different signals with preset displacement values ​​to calibrate the X-axis and Y-axis displacements of the wafer testing system. The reflector in the laser interferometer is mounted on the probe station.

[0045] Furthermore, the wafer testing system calibration device provided in this embodiment may also include:

[0046] The temperature parameter calibration module is used to send cooling and heating signals to the temperature control component at intervals, while acquiring temperature information detected by the temperature sensor; then, it compares the temperature information acquired under different signals with the preset temperature value to calibrate the temperature parameters of the wafer testing system.

[0047] Specifically, the functions of each module provided in this embodiment can be found in the detailed description in the foregoing method embodiments, and will not be repeated in this embodiment.

[0048] Based on the same inventive concept, the present invention also provides a calibration method for a wafer testing system, such as... Figure 5As shown, this calibration method is implemented through a wafer testing system calibration device and a host computer. Specifically, the calibration method includes steps S10 to S30, which are detailed below:

[0049] S10: Establish network communication between the wafer test system calibration device and the host computer, and send a self-test signal to the wafer test system calibration device through the host computer, so that the wafer test system calibration device can complete the self-test operation.

[0050] S20: The host computer controls the wafer testing system calibration device to send a standard source control signal to the test machine in the wafer testing system. The wafer testing system calibration device collects the first electrical signal sent by the test machine and transmitted to the probe card through the adapter, and the second electrical signal detected by the probe card and transmitted back to the test machine. The first electrical signal is compared with the electrical signal set by the test machine, and the second electrical signal is compared with the preset electrical signal, thereby realizing the integrity calibration of the electrical parameters of the wafer testing system test machine; at the same time, the electrical parameter calibration data is transmitted back to the host computer.

[0051] S30: The host computer controls the wafer testing system calibration device to send X-axis and Y-axis displacement signals to the probe station at preset time intervals. The wafer testing system calibration device acquires the displacement information of the probe station measured by the laser interferometer. Then, it compares the displacement information acquired under different signals with the preset displacement values ​​to calibrate the X-axis and Y-axis displacements of the wafer testing system, and simultaneously transmits the displacement parameter calibration data back to the host computer. The reflector in the laser interferometer is mounted on the probe station.

[0052] The calibration method provided in this embodiment can directly generate calibration reports from the calibration data of each parameter via a host computer, reducing the workload of calibration service personnel.

[0053] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A calibration method for a wafer testing system, applied to a wafer testing system calibration device, characterized in that, The wafer testing system includes a tester, a probe station, a wafer carrier, and probe cards. The calibration method includes electrical parameter calibration and displacement parameter calibration. The calibration method for the electrical parameters is as follows: a standard source control signal is sent to the tester in the wafer testing system, and a first electrical signal transmitted from the tester to the probe card via an adapter and a second electrical signal detected and transmitted back to the tester by the probe card are collected; the first electrical signal is compared with the electrical signal set by the tester, and the second electrical signal is compared with the preset electrical signal, thereby achieving complete calibration of the electrical parameters of the tester in the wafer testing system; The calibration method for the displacement parameter calibration is as follows: X-axis and Y-axis displacement signals are sent to the probe station at preset time intervals, and the displacement information of the probe station measured by the laser interferometer is acquired at the same time; then the displacement information acquired under different signals is compared with the preset displacement value, thereby realizing the calibration of the X-axis and Y-axis displacement of the wafer testing system; wherein, the reflector in the laser interferometer is mounted on the probe station.

2. The calibration method for the wafer testing system according to claim 1, characterized in that, In electrical parameter calibration, the wafer testing system calibration device and the tester in the wafer testing system transmit signals through a calibration interface board, which is set on the wafer support stage. The calibration interface board is provided with a number of contact PADs. The number and distribution of the contact PADs are set according to the number and distribution of probes in the probe card. The calibration interface board is also provided with an SMA interface, which is electrically connected to the contact PADs.

3. The calibration method for the wafer testing system according to claim 2, characterized in that, The SMA interface and several contact pads are all located on the upper surface of the calibration interface board.

4. The calibration method for the wafer testing system according to claim 1, characterized in that, The wafer testing system is equipped with a temperature sensor and a temperature control component on the wafer support stage; The calibration method further includes temperature calibration, which involves sending cooling and heating signals to the temperature control component at intervals while acquiring temperature information detected by the temperature sensor; then comparing the temperature information acquired under different signals with a preset temperature value to calibrate the temperature parameters of the wafer testing system.

5. The calibration method for the wafer testing system according to claim 4, characterized in that, The temperature sensor is a flexible PT100 temperature sensor.

6. The calibration method for the wafer testing system according to claim 4, characterized in that, The wafer testing system calibration device includes: The electrical parameter calibration module is used to send a standard source control signal to the tester in the wafer testing system, and to collect the first electrical signal transmitted from the tester to the probe card via an adapter, and the second electrical signal detected by the probe card and transmitted back to the tester; the first electrical signal is compared with the electrical signal set by the tester, and the second electrical signal is compared with the preset electrical signal, thereby realizing the integrity calibration of the electrical parameters of the wafer testing system; The displacement parameter calibration module is used to send X-axis and Y-axis displacement signals to the probe station at preset time intervals, and at the same time acquire the displacement information of the probe station measured by the laser interferometer. The displacement information acquired under different signals is compared with the preset displacement values ​​to achieve calibration of the X-axis and Y-axis displacement of the wafer testing system; wherein, the reflector in the laser interferometer is mounted on the probe station.

7. The calibration method for the wafer testing system according to claim 6, characterized in that, The wafer testing system is equipped with a temperature sensor and a temperature control component on the wafer support stage; the wafer testing system calibration device includes a temperature parameter calibration module. The temperature parameter calibration module is used to send cooling and heating signals to the temperature control component at intervals, and at the same time acquire the temperature information detected by the temperature sensor; then, it compares the temperature information acquired under different signals with the preset temperature value to achieve calibration of the temperature parameters of the wafer testing system.

8. A calibration method for a wafer testing system, applied to a wafer testing system calibration device and a host computer, characterized in that, The wafer testing system includes a tester, a probe station, a wafer carrier, and a probe card. The calibration method includes the following steps: (1) Establish network communication between the wafer test system calibration device and the host computer, and send a self-test signal to the wafer test system calibration device through the host computer so that the wafer test system calibration device can complete the self-test operation; (2) The host computer controls the wafer testing system calibration device to send a standard source control signal to the test machine in the wafer testing system. The wafer testing system calibration device collects the first electrical signal sent by the test machine and transmitted to the probe card through the adapter, and the second electrical signal detected by the probe card and transmitted back to the test machine. The first electrical signal is compared with the electrical signal set by the test machine, and the second electrical signal is compared with the preset electrical signal, thereby realizing the integrity calibration of the electrical parameters of the test machine in the wafer testing system. At the same time, the electrical parameter calibration data is transmitted back to the host computer. (3) The upper computer controls the wafer testing system calibration device to send X-axis and Y-axis displacement signals to the probe station at preset time intervals. The wafer testing system calibration device obtains the displacement information of the probe station measured by the laser interferometer. Then, the displacement information obtained under different signals is compared with the preset displacement value to realize the calibration of the X-axis and Y-axis displacement of the wafer testing system. At the same time, the displacement parameter calibration data is sent back to the upper computer. The reflector in the laser interferometer is installed on the probe station.

9. The calibration method for the wafer testing system according to claim 8, characterized in that, The host computer is used to process the electrical parameter calibration data and temperature calibration data according to the user's operation instructions and then generate a calibration report.

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