A non-contact wafer resistance measurement device and method

Abstract

This application provides a non-contact wafer resistance measurement device and method, belonging to the field of semiconductor testing. A rotary motor drives the loading platform to rotate, enabling the switching of measurement points on the circumference of the wafer under test. A linear guide rail drives the probe linear module to move radially along the wafer under test, enabling radial measurement point switching. The probe linear module drives the coil probe in the data acquisition module to move in a direction perpendicular to the wafer under test, adjusting the distance between the coil probe and the wafer. A distance sensor measures the distance between the wafer under test and the coil probe in real time. The coil probe measures the resistance at each measurement point on the wafer under test under the influence of current. This application significantly improves the accuracy of wafer resistance measurement.

Description

Technical Field

[0001] This application belongs to the field of semiconductor testing, and more specifically, relates to a non-contact wafer resistance measurement device and method. Background Technology

[0002] Semiconductor testing assesses the functionality and parameters of integrated circuits to determine the conformity of the tested wafers / chips. It provides information on weak points in the chip design and manufacturing process, making it a core component throughout integrated circuit design and production, and crucial for improving chip yield and reducing costs. Among these parameters, resistance is a critical front-end inspection parameter in wafer manufacturing, directly affecting the quality of the wafer film and the reliability of the formed chip. Currently, the widely used resistance measurement equipment is the four-probe tester, which uses a contact method with probes for measurement. However, the contact pressure between the probes and the tested wafer cannot be controlled, and the probes are prone to damaging the wafer surface, significantly impacting the accuracy of the test results. Four-probe testers are particularly unsuitable for thin, fragile wafers or wafers with thin coating layers.

[0003] In contrast, non-contact measurement devices based on the eddy current effect can effectively solve the problem of damage during wafer testing and are very suitable for resistance measurement of thinner and softer wafers. Because wafer resistance is extremely sensitive to the distance between the coil probe and the wafer being measured, and because the wafer surface is not entirely on a single plane, the distance between each measurement point varies, altering the measurement conditions and affecting the accuracy of the measurement results. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this application is to provide a non-contact wafer resistance measurement device and method, which aims to solve the problem that the wafer surface is not completely flat, resulting in different distances between the coil probes at each measurement point and the wafer being measured, thus altering the measurement conditions and leading to poor accuracy in wafer resistance measurement.

[0005] To achieve the above objectives, this application provides a non-contact wafer resistance measurement device, comprising: a loading motion module and a data acquisition module;

[0006] The loading motion module includes a loading platform, a linear guide rail, a rotary motor, and a probe linear module. The lower surface of the loading platform is connected to the rotary motor, and the interior is an air passage cavity. The upper surface is machined with air suction holes so that the wafer to be tested can be fixed by air suction. The probe linear module is mounted on the linear guide rail.

[0007] A rotary motor drives the loading platform to rotate, enabling the switching of test points on the circumference of the wafer under test; a linear guide rail drives the probe linear module to move radially along the wafer under test, enabling the switching of test points in the radial direction; the probe linear module drives the coil probe in the data acquisition module to move in a direction perpendicular to the wafer under test, adjusting the distance between the coil probe and the wafer under test.

[0008] The data acquisition module includes a distance sensor and a coil probe; the distance sensor is used to measure the distance between the wafer under test and the coil probe in real time; the coil probe is used to measure the resistance of each measuring point on the wafer under test under the action of current.

[0009] More preferably, the non-contact wafer resistance measurement device further includes a human-machine interface, a drive control module, and a power supply module;

[0010] The output current source in the power supply module and drive control module is installed in the bottom box; the data acquisition module also includes a signal acquisition board; the signal acquisition board, the motor driver and motion control board in the drive control module are installed in the tail box, and the tail box is provided with an external interface for a human-machine interface.

[0011] The human-machine interface is used for parameter setting, path planning for testing the wafer under test, and displaying and saving resistance measurement data;

[0012] The drive control module includes an output current source, a motor driver, and a motion control board; the output current source provides a constant current output to the coil probe; the motor driver drives and controls the rotating motor; the motion control board controls the movement of the probe linear module according to the set target distance value; and the power supply module provides a stable power supply.

[0013] More preferably, the loading motion module further includes: a probe fixing support and a bracket; the probe fixing support is mounted on the probe linear module; a coil probe is provided below the probe fixing support, and a distance sensor is mounted on the side of the coil probe; the bracket is mounted on the base box, and a linear guide rail is mounted on the bracket.

[0014] Secondly, this application provides a measurement method for a non-contact wafer resistance measuring device, comprising the following steps:

[0015] Step 1: Use a linear guide rail to drive the probe linear module and coil probe to the center position of the loading platform. When the center of the coil probe coincides with the center of the loading platform, take the position of the linear guide rail as the zero position of the measurement.

[0016] Step 2: Move the linear guide to the side and simultaneously move the probe linear module away from the loading platform. After placing the wafer to be tested on the loading platform, move the linear guide to the zero position and move the probe linear module downward so that the distance between the coil probe and the wafer to be tested reaches the first set value.

[0017] Step 3: Move the coil probe to the current measuring point, stop the linear guide and rotary motor from moving, and use the probe linear module to adjust the spacing to the second set value;

[0018] Step 4: Measure the resistance of the wafer at the current measurement point.

[0019] More preferably, the measurement method of the non-contact wafer resistance measuring device further includes the following steps:

[0020] The movement of the linear guide rail and the rotary motor respectively realizes the switching of different measurement points on the wafer under test in the radial and circumferential directions, and then proceeds to step 3 until the resistance values ​​of all measurement points are obtained.

[0021] More preferably, the method for changing different test wafers is as follows:

[0022] Move the probe linear module to its highest position, so that the coil probe is away from the current wafer being tested, and change to a different wafer being tested.

[0023] More preferably, the measurement method of the non-contact wafer resistance measuring device further includes: displaying the resistance value of the measured point on the human-machine interface, judging the validity and correctness of the currently measured resistance value, and marking it according to the judgment result.

[0024] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art:

[0025] This application provides a non-contact wafer resistance measurement device, wherein a distance sensor is installed on the side of the coil probe, which continuously detects the distance between the probe and the wafer being measured during the measurement process. At the same time, the distance is finely adjusted by the probe linear module, which greatly improves the accuracy of wafer resistance measurement. The probe linear module has a certain stroke and can move to the top. Simultaneously, it moves to both sides of the loading platform under the drive of the linear guide rail, which facilitates the installation and removal of the wafer being measured.

[0026] This application provides a non-contact wafer resistance measurement device. The upper surface of the loading platform is provided with air suction holes and the inside is an air suction cavity. During the measurement process, the wafer to be measured is fixed on the loading platform by the principle of vacuum adsorption, so that the wafer to be measured will not slide relative to the loading platform during high-speed rotation. No other clamps are needed to fix the wafer to be measured, avoiding deformation or even damage to the wafer caused by the force generated by the clamps.

[0027] This application provides a non-contact wafer resistance measurement device. During the measurement process, the coil probe does not need to contact the wafer being measured to complete the measurement, and will not cause any scratches or compression damage to the wafer being measured, thus achieving non-destructive measurement.

[0028] This application provides a non-contact wafer resistance measurement device, which adopts a gantry bracket and rotary motor design. The rotary motor does not need to move in the horizontal plane. It realizes the measurement of the entire area of ​​the wafer under test by means of polar coordinate movement. This design separates the rotary axis used for circumferential movement of the wafer and the linear axis used for radial movement, avoiding the stacking of two main motion axes and reducing errors caused by insufficient assembly accuracy.

[0029] This application provides a non-contact wafer resistance measurement device, which arranges the driving, control and acquisition hardware at the bottom and tail of the gantry support, making the device compact and with a very small space volume. While meeting the measurement requirements of large-size wafers, it also takes into account the requirements of lightweight and miniaturization, realizing a desktop-level design for the measurement device. Attached Figure Description

[0030] Figure 1 This is a 3D structural diagram of a non-contact wafer resistance measuring device provided in an embodiment of this application;

[0031] Figure 2 This is a system composition diagram of a non-contact wafer resistance measuring device provided in an embodiment of this application;

[0032] Figure 3 This is a structural diagram of a loading platform for a non-contact wafer resistance measuring device provided in an embodiment of this application;

[0033] Figure 4 This is a top view of the cover plate of the loading platform of a non-contact wafer resistance measuring device provided in an embodiment of this application;

[0034] Figure 5 This is a structural diagram of the air suction cavity of the loading platform of a non-contact wafer resistance measuring device provided in an embodiment of this application;

[0035] Figure 6 This is a structural diagram of the probe fixing support and coil probe of a non-contact wafer resistance measuring device provided in an embodiment of this application;

[0036] Explanation of markings in the attached diagram:

[0037] A- Loading platform cover; B- Loading platform air suction cavity; a- Air suction hole on cover; b- Cover mounting hole; c- Cover edge fixing hole; d- Cavity of air suction cavity; e- Air extraction hole of air suction cavity; f- Mounting threaded hole of air suction cavity; g- Sealing rubber ring mounting groove of air suction cavity; h- Probe mounting positioning hole of probe fixing support; 1- Loading platform; 2- Linear guide rail; 3- Rotary motor; 4- Probe linear module; 5- Probe fixing support; 6- Bracket; 7- Distance sensor; 8- Coil probe; 9- Signal acquisition board; 10- Protective cover; 11- Tail box; 12- Bottom box; 13- Power supply module. Detailed Implementation

[0038] The embodiments of this application are described below with reference to the accompanying drawings.

[0039] This application employs a non-contact measurement method based on the eddy current effect. By dynamically adjusting the spacing between the probe linear module in the measurement device and the wafer, non-destructive measurement of wafer resistance is achieved while ensuring consistent measurement spacing, covering a 12-inch wafer range.

[0040] Firstly, such as Figure 1 and 2 As shown, this application provides a non-contact wafer resistance measurement device, including: a human-machine interface, a loading motion module, a data acquisition module, a drive control module, and a power supply module;

[0041] The human-machine interface (HMI) serves as the operating software for the measuring device, providing functions such as parameter setting, path planning, data display, and saving. The loading motion module includes: a loading platform 1, a linear guide rail 2, a rotary motor 3, a probe linear module 4, a probe fixing support 5, and a bracket 6. The loading platform provides support for the installation, fixation, and movement of the wafer under test. The data acquisition module includes a distance sensor 7, a coil probe 8, and a signal acquisition board 9, used for acquiring and filtering data such as distance signals, wafer resistance, and motion parameters. The drive control module includes an output current source, a motor driver, and a motion control board, used to provide constant current output to the coil probe, motor drive control, and multi-axis joint control. The power supply module provides a stable power supply for the entire device. The power supply module 13 and the output current source in the drive control module are installed in the base box 12; the signal acquisition board 9, the motor driver in the drive control module, and the motion control board are installed in the tail box 11, with an external interface for the HMI provided in the tail box.

[0042] like Figure 3 and Figure 4 As shown, the lower surface of the loading platform 1 is connected to the rotary motor 3, and the wafer to be tested is placed on the upper surface. The interior is a pneumatic suction cavity B, the specific structure of which is as follows. Figure 5As shown, a suction hole e is provided in the middle, and a cavity d with a suction cavity B is provided around it. The edges are provided with mounting threaded holes for the suction cavity and mounting grooves for sealing rubber rings. A suction hole a is machined on the cover plate A on the upper surface of the loading platform 1. The wafer to be tested is fixed to the loading platform 1 by suction. The cover plate A is provided with mounting fixing holes b and edge fixing holes c, which fix the cover plate A to the loading platform 1. The loading platform 1 is connected to a rotary motor 3, which is installed in the base box 12. A bracket 6 is installed on the base box 12, and a linear guide rail 2 is installed on the bracket 6. A probe linear module 4 is installed on the linear guide rail 2. A probe fixing support 5 is installed on the probe linear module 4, i.e., through... Figure 6 The probe mounting positioning hole h of the probe fixing support shown is used to install the probe fixing support; the distance sensor 7 is installed on the side end of the coil probe 8, as shown. Figure 6 As shown;

[0043] During measurement, the rotary motor 3 drives the loading platform 1 to rotate, realizing the switching of the points on the circumference of the wafer being measured; the linear guide rail 2 drives the probe linear module 4 to move along the radial direction of the wafer being measured, realizing the switching of the points on the radial direction; the probe linear module 4 drives the coil probe 8 to move in a direction perpendicular to the wafer being measured, adjusting the distance between the coil probe 8 and the wafer being measured.

[0044] Furthermore, when measuring resistance at different positions on the wafer under test, the distance sensor 7 measures the distance between the coil probe 8 and the wafer under test in real time. The motion control board controls the movement of the probe linear module 4 according to the set target distance value. Once the distance meets the requirements, the resistance data acquisition at that position begins.

[0045] Secondly, this application provides a measurement method for a non-contact wafer resistance measuring device, comprising the following steps:

[0046] S1: The linear guide rail drives the probe linear module and the coil probe to the center position of the loading platform. The probe linear module drives the coil probe to approach the loading platform. Adjust the probe fixing support to ensure that the center of the coil probe coincides with the center of the loading platform. At this time, the position of the linear guide rail is used as the zero position of the measurement.

[0047] S2: During loading, the linear guide rail moves to the side of the support, while the probe linear module moves away from the loading platform and places the wafer to be tested on the loading platform. The center of the wafer to be tested is required to coincide with the center of the loading platform. The linear guide rail moves to the zero position, and the probe linear module moves downward so that the distance between the coil probe and the wafer to be tested reaches the set value.

[0048] S3: When measuring a certain measuring point, after the coil probe moves to the designated position, the linear guide rail and the rotary motor stop moving. The distance sensor detects the distance between itself and the wafer being measured, and the probe linear module is used to fine-tune the spacing to achieve the set value.

[0049] S4: Measure and collect the resistance value of the wafer under test at the current measurement point, record the position data, display it on the human-machine interface, judge the validity and correctness of the currently measured data, and mark it according to the judgment result;

[0050] S5: The movement of the linear guide rail and the rotary motor respectively realizes the switching of different measurement points of the wafer under test in the radial and circumferential directions. Repeat steps S3 to S4 to complete the resistance measurement of all measurement points in sequence, and display the measurement results on the human-machine interface.

[0051] S6: Based on the marking of all measuring points, repeat steps S3 to S4 to perform a second measurement on the measuring points with inaccurate measurement results;

[0052] S7: After all measurement points are completed, save the measurement results data from the human-machine interface, move the probe linear module to the top so that the coil probe is away from the wafer being measured, change to a different wafer being measured, and repeat the above steps to complete the measurement.

[0053] In summary, this application has the following advantages compared with the prior art:

[0054] In this application, the rotary motor, linear guide, probe linear module, and coil probe can complete the measurement without contacting the wafer being measured, thus avoiding any scratches or damage to the wafer and achieving non-destructive measurement.

[0055] In this application, the upper surface of the loading platform is a cover plate with multiple air suction holes and the interior is an air suction cavity. During the measurement process, the wafer to be measured is fixed on the loading platform by the principle of vacuum adsorption, so that the wafer to be measured will not slide relative to the loading platform during high-speed rotation. No other clamps are needed to fix the wafer to be measured, thus avoiding deformation or even damage to the wafer caused by the force generated by the clamps.

[0056] In this application, a distance sensor is installed on the side of the coil probe. During the measurement process, the distance between the probe and the wafer under test is continuously detected. At the same time, the distance is finely adjusted using a probe linear module. The probe linear module has a certain stroke and can move up to the top. Simultaneously, it moves to both sides of the loading platform under the drive of the linear guide rail, which facilitates the installation and removal of the wafer under test.

[0057] This application adopts a gantry support and rotary motor design. The rotary motor does not need to move in the horizontal plane. It realizes the measurement of the entire area of ​​the wafer under test by means of polar coordinate movement. This design separates the rotation axis used for the circumferential movement of the wafer and the linear axis used for the radial movement, avoiding the stacking of two main motion axes and reducing errors caused by insufficient assembly accuracy.

[0058] This application arranges the hardware related to driving, control, and acquisition at the bottom and tail of the gantry support, making the device compact and with a very small volume. While meeting the measurement requirements of large-size wafers, it also takes into account the requirements of lightweight and miniaturization, realizing a desktop-level design for the measurement device.

[0059] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0060] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0061] Furthermore, the mathematical concepts mentioned in the embodiments of this application, such as symmetry, equality, parallelism, and perpendicularity, are limitations specific to the current technological level, rather than absolute and strict mathematical definitions. Slight deviations are permissible; approximations of symmetry, equality, parallelism, and perpendicularity are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. "A and B are perpendicular" means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0062] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A non-contact wafer resistance measuring device, characterized in that, include: Loading motion module and data acquisition module; The loading motion module includes a loading platform, a linear guide rail, a rotary motor, and a probe linear module. The lower surface of the loading platform is connected to the rotary motor, and the interior is an air passage cavity. The upper surface is machined with air suction holes so that the wafer to be tested can be fixed by air suction. The probe linear module is mounted on the linear guide rail. A rotary motor drives the loading platform to rotate, enabling the switching of measurement points on the circumference of the wafer under test. A linear guide rail drives the probe linear module to move radially along the wafer under test, enabling the switching of measurement points radially. The probe linear module drives the coil probe in the data acquisition module to move in a direction perpendicular to the wafer under test, adjusting the distance between the coil probe and the wafer under test. When the center of the coil probe coincides with the center of the loading platform, the position of the linear guide rail is used as the zero position of the measurement. The data acquisition module includes a distance sensor and a coil probe; the distance sensor is used to measure the distance between the wafer under test and the coil probe in real time; the coil probe is used to measure the resistance of each measuring point on the wafer under test under the action of current.

2. The non-contact wafer resistance measuring device according to claim 1, characterized in that, Also includes: Human-computer interaction interface, drive control module and power supply module; The output current sources in the power supply module and drive control module are installed in the base box; The data acquisition module also includes a signal acquisition board; the signal acquisition board, the motor driver and motion control board in the drive control module are installed in the tail box, and the tail box is equipped with an external interface for a human-machine interface; The human-machine interface is used for parameter setting, path planning for testing the wafer under test, and displaying and saving resistance measurement data; The drive control module includes an output current source, a motor driver, and a motion control board; The output current source is used to provide a constant current output to the coil probe; Motor drivers are used for driving and controlling rotating motors; The motion control board is used to control the movement of the probe linear module according to a set target distance value; The power supply module is used to provide a stable power supply.

3. The non-contact wafer resistance measuring device according to claim 1 or 2, characterized in that, The loading motion module also includes: a probe fixing support and a bracket; the probe fixing support is mounted on the probe linear module; a coil probe is set below the probe fixing support, and a distance sensor is mounted on the side of the coil probe; the bracket is mounted on the base box, and a linear guide rail is mounted on the bracket.

4. A measurement method based on the non-contact wafer resistance measuring device according to claim 1, characterized in that it employs a non-contact measurement method based on the eddy current effect, Includes the following steps: Step 1: Use a linear guide rail to drive the probe linear module and coil probe to the center position of the loading platform. When the center of the coil probe coincides with the center of the loading platform, take the position of the linear guide rail as the zero position of the measurement. Step 2: Move the linear guide to the side and simultaneously move the probe linear module away from the loading platform. After placing the wafer to be tested on the loading platform, move the linear guide to the zero position and move the probe linear module downward so that the distance between the coil probe and the wafer to be tested reaches the first set value. Step 3: Move the coil probe to the current measuring point, stop the linear guide and rotary motor from moving, and use the probe linear module to adjust the spacing to the second set value; Step 4: Measure the resistance of the wafer at the current measurement point.

5. The measurement method according to claim 4, characterized in that, It also includes the following steps: The movement of the linear guide rail and the rotary motor respectively realizes the switching of different measurement points on the wafer under test in the radial and circumferential directions, and then proceeds to step 3 until the resistance values ​​of all measurement points are obtained.

6. The measurement method according to claim 4 or 5, characterized in that, The method for changing to different test wafers is as follows: Move the probe linear module to its highest position, so that the coil probe is away from the current wafer being tested, and change to a different wafer being tested.

7. The measurement method according to claim 4 or 5, characterized in that, Also includes: The measured resistance value is displayed on the human-computer interaction interface, and the validity and correctness of the measured resistance value are judged and marked according to the judgment result.

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