Non-contact wafer resistance measuring device and method

Abstract

The invention provides a non-contact wafer resistance measuring device and method, and belongs to the field of semiconductor testing, a rotating motor is used for driving a loading platform to rotate, and distribution point switching in the circumferential direction of a tested wafer is achieved; the linear guide rail is used for driving the probe linear module to move along the radial direction of the tested wafer so as to realize distribution point switching in the radial direction; the probe linear module drives a coil probe in the data acquisition module to move in the direction perpendicular to the tested wafer, and the distance between the coil probe and the tested wafer is adjusted; the distance sensor is used for measuring the distance between the measured wafer and the coil probe in real time; and the coil probe is used for measuring the resistance of each measuring point of the to-be-measured wafer under the action of the current. According to the invention, the precision of wafer resistance measurement is greatly improved.

Description

Technical Field

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

[0002] Semiconductor testing determines the eligibility of the wafer / chip under test by testing the functions and parameters of integrated circuits, and provides information on weak links in the chip design and manufacturing process. It is the core link throughout the integrated circuit design and production process, and is also the key to improving chip yield and reducing costs. Among them, resistance parameters, as an important parameter for front-end detection in the wafer manufacturing process, directly affect the quality of the wafer film and the performance reliability of the formed chip. The widely used resistance parameter measurement equipment at present is a four-probe measuring instrument, which uses a contact method with a probe for measurement. However, the contact pressure between the probe and the wafer under test cannot be controlled during measurement, and the probe can easily damage the wafer surface, greatly affecting the accuracy of the test results. In particular, for thinner, softer and more fragile wafers, or wafers with thinner coating layers, it is not suitable to use a four-probe tester for measurement.

[0003] In contrast, non-contact measurement equipment based on the eddy current effect can effectively solve the problem of damage during wafer testing and is very suitable for resistance measurement of thinner and softer wafers. Since the wafer resistance is extremely sensitive to the distance between the coil probe and the wafer being measured, and the wafer surface is not completely in one plane, the distances between the measurement points are different, which changes the measurement conditions and affects the accuracy of the measurement results. Summary of the invention

[0004] In view of the defects of the prior art, 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 surface of the existing wafer is not completely in a plane, resulting in different distances between the coil probe and the wafer under test corresponding to each measuring point when measuring the wafer resistance, causing the measurement conditions to change, and thus resulting in poor accuracy of wafer resistance measurement.

[0005] To achieve the above-mentioned object, the present application provides a non-contact wafer resistance measurement device, comprising: a loading movement 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, the interior is an air path cavity, and the upper surface is processed with air suction holes so that the wafer to be tested can be fixed by air suction; the probe linear module is installed on the linear guide rail;

[0007] The rotary motor is used to drive the loading platform to rotate, so as to realize the switching of the points in the circumferential direction of the wafer under test; the linear guide is used to drive the probe linear module to move along the radial direction of the wafer under test, so as to realize the switching of the points in the radial direction; the probe linear module drives the coil probe in the data acquisition module to move in the direction perpendicular to the wafer under test, so as to adjust 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 to be tested and the coil probe in real time; the coil probe is used to measure the resistance of each measuring point of the wafer to be tested under the action of current.

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

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

[0011] The human-computer interaction interface is used for parameter setting, path planning for wafer testing, and display and storage of 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 is used to provide a constant current output for the coil probe; the motor driver is used to drive and control the rotating motor; the motion control board is used to control the movement of the probe linear module according to the set target distance value; the power supply module is used to provide a stable power supply.

[0013] Further preferably, the loading motion module also includes: a probe fixing support and a bracket; the probe fixing support is installed on the probe linear module; a coil probe is arranged below the probe fixing support, and the distance sensor is installed on the side end of the coil probe; the bracket is installed on the bottom box, and a linear guide rail is installed on the bracket.

[0014] In a second aspect, the present application provides a measurement method of a non-contact wafer resistance measurement device, comprising the following steps:

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

[0016] Step 2: Move the linear guide rail to the side, and at the same time 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 rail 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 a first set value;

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

[0018] Step 4: Measure the resistance value of the wafer under test at the current measuring point.

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

[0020] The switching of different measuring points of the wafer under test in the radial direction and the circumferential direction is respectively realized by the movement of the linear guide and the rotary motor, and then the process goes to step 3 until the resistance values ​​of all the measuring points are obtained.

[0021] Further preferably, the method of replacing different wafers to be tested is:

[0022] Move the probe linear module to the top, so that the coil probe is away from the current wafer to be tested, and replace a different wafer to be tested.

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

[0024] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0025] The present application provides a non-contact wafer resistance measurement device, in which a distance sensor is installed at the side end of the coil probe, which will continuously detect the distance between the coil probe and the wafer to be measured during the measurement process, and at the same time use the probe linear module to fine-tune the distance, thereby greatly improving the accuracy of the wafer resistance measurement; the probe linear module has a certain stroke and can be moved up to the top, and at the same time, driven by a linear guide rail, it can be moved to both sides of the loading platform, so as to facilitate the installation and removal of the wafer to be measured.

[0026] The present application provides a non-contact wafer resistance measuring device, wherein the upper surface of the loading platform is provided with an air suction hole, and the interior is an air suction cavity. During the measurement process, the measured wafer is fixed on the loading platform by the principle of vacuum adsorption, so that the measured wafer will not slide relative to the loading platform during high-speed rotation, and no other clamps are required to fix the measured wafer, thereby avoiding deformation or even damage of the measured wafer due to the force generated by the clamp.

[0027] The present application provides a non-contact wafer resistance measurement device. During the measurement process, the coil probe does not need to contact the wafer to be measured to complete the measurement, and will not cause any scratches, squeezing or other damage to the wafer to be measured, thereby achieving non-destructive measurement.

[0028] The present application provides a non-contact wafer resistance measuring device, which adopts the design of a gantry bracket and a rotating motor. The rotating motor does not need to move in the horizontal plane, and the full-area measurement of the measured wafer is achieved by polar coordinate movement. This design separates the rotating axis used for the circumferential movement of the wafer and the linear axis for radial movement, avoiding the stacking of two moving spindles and reducing the errors caused by insufficient assembly accuracy.

[0029] The present application provides a non-contact wafer resistance measurement device, in which the related hardware such as drive, control and acquisition are arranged at the bottom and tail of the gantry bracket, so that the structure of the device is compact and the space volume is very small. While meeting the measurement needs of large-size wafers, it also takes into account the lightweight and miniaturization requirements of the device, realizing a desktop-level design of the measurement device. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0031] Figure 2 is a system composition diagram of a non-contact wafer resistance measurement device provided in an embodiment of the present application;

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

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

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

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

[0036] Description of the symbols in the accompanying drawings:

[0037] A-cover plate of loading platform; B-air suction cavity of loading platform; a-air suction hole on the cover plate; b-installation fixing hole of the cover plate; c-edge fixing hole of the cover plate; d-cavity of the air suction cavity; e-exhaust hole of the air suction cavity; f-installation threaded hole of the air suction cavity; g-installation groove of the sealing rubber ring of the air suction cavity; h-probe installation positioning hole of the probe fixing support; 1-loading platform; 2-linear guide; 3-rotating 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 DESCRIPTION

[0038] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0039] This application adopts a non-contact measurement method based on the eddy current effect. The linear module of the probe in the measuring device dynamically adjusts the distance from the wafer, thereby achieving non-destructive measurement of the wafer resistance while ensuring consistent measurement distance, covering a 12-inch wafer range.

[0040] First, as Figure 1 and 2 As shown, the present application provides a non-contact wafer resistance measurement device, including: a human-computer interaction interface, a loading motion module, a data acquisition module, a drive control module and a power supply module;

[0041] The human-machine interaction interface is the operating software of the measuring device, which has functions such as parameter setting, path planning, data display and storage; the loading and motion module includes: loading platform 1, linear guide 2, rotating motor 3, probe linear module 4, probe fixing support 5 and bracket 6; the loading platform is used to provide support for the installation, fixation and movement of the wafer under test; the data acquisition module includes distance sensor 7, coil probe 8 and signal acquisition board 9, which are used for the collection and filtering of distance signals, wafer resistance and motion parameters and other data; the drive control module includes output current source, motor driver and motion control board, which are used to provide constant current output, motor drive control and multi-axis joint control for the coil probe; the power supply module provides stable power for the entire device. The power supply module 13 and the output current source in the drive control module are installed in the bottom box 12; the signal acquisition board 9, the motor driver and the motion control board in the drive control module are installed in the tail box 11, and an external interface for the human-machine interaction interface is reserved 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 rotating motor 3, and the wafer to be tested is placed on the upper surface. The interior is an air suction cavity B. The specific structure of the air suction cavity is as follows: Figure 5As shown, an exhaust hole e is provided in the middle, a cavity d with an air suction cavity B is provided around it, and a mounting threaded hole for the air suction cavity and a sealing rubber ring mounting groove g are provided on the edge; an air suction hole a is processed on the cover plate A on the upper surface of the loading platform 1, and the wafer to be tested is fixed on the loading platform 1 by air suction, wherein the cover plate A is provided with mounting fixing holes b and edge fixing holes c, so that the cover plate A is fixed on the loading platform 1; the loading platform 1 is connected to the rotating motor 3, and the rotating motor 3 is installed in the bottom box 12; the bracket 6 is installed on the bottom box 12, and a linear guide 2 is installed on the bracket 6, and a probe linear module 4 is installed on the linear guide 2; the probe fixing support 5 is installed on the probe linear module 4, that is, through the following Figure 6 The probe fixing support is installed by the probe mounting positioning hole h of the probe fixing support shown in the figure; the distance sensor 7 is installed at the side end of the coil probe 8, as shown in FIG. Figure 6 As shown;

[0043] During measurement, the rotating motor 3 drives the loading platform 1 to rotate to realize the switching of the points in the circumferential direction of the wafer to be measured; the linear guide rail 2 drives the probe linear module 4 to move along the radial direction of the wafer to be measured to realize the switching of the points in the radial direction; the probe linear module 4 drives the coil probe 8 to move in a direction perpendicular to the wafer to be measured to adjust the distance between the coil probe 8 and the wafer to be measured;

[0044] Furthermore, when measuring resistance at different positions of the wafer under test, the distance sensor 7 will measure 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. When the distance meets the requirements, the resistance data collection at this position will begin.

[0045] In a second aspect, the present application provides a measurement method of a non-contact wafer resistance measurement device, comprising the following steps:

[0046] S1: The linear guide rail drives the probe linear module and the coil probe to move to the center of the loading platform. The probe linear module drives the coil probe close to the loading platform. The probe fixed support is adjusted 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: When loading, the linear guide moves to the side end of the bracket, and the probe linear module moves away from the loading platform. The wafer to be tested is placed 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 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 specified position, the linear guide and the rotary motor stop moving, the distance sensor detects the distance to the wafer being measured, and the probe linear module is used to fine-tune the spacing to reach the set value;

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

[0050] S5: Switching between different measuring points of the wafer under test in the radial and circumferential directions is achieved through the movement of the linear guide and the rotary motor, and steps S3 to S4 are repeated to complete the resistance measurement of all measuring points in sequence, and the measurement results are displayed on the human-computer interaction interface;

[0051] S6: Repeat steps S3 to S4 according to the marking conditions of all measuring points, and perform secondary measurement on the measuring points with inaccurate measurement results;

[0052] S7: After all the measurement points are measured, the measurement result data of the human-computer interaction interface is saved, the probe linear module is moved to the top end so that the coil probe is away from the wafer to be measured, a different wafer to be measured is replaced, and the above steps are repeated to complete the measurement.

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

[0054] In the present application, the rotating motor, linear guide rail, probe linear module and coil probe can complete the measurement without the coil probe contacting the wafer under test during the measurement process, and will not cause any scratches, squeezing or other damage to the wafer under test, thus achieving non-destructive measurement.

[0055] In the present 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 principle of vacuum adsorption is used to fix the wafer to be measured on the loading platform, so that the wafer to be measured will not slide relative to the loading platform during high-speed rotation, and no other clamps are required to fix the wafer to be measured, thereby avoiding deformation or even damage of the wafer to be measured due to the force generated by the clamp.

[0056] In this application, a distance sensor is installed on the side end of the coil probe, which will continuously detect the distance between the coil probe and the wafer under measurement during the measurement process, and use the probe linear module to fine-tune the distance; the probe linear module has a certain stroke and can move up to the top, and at the same time move to both sides of the loading platform driven by the linear guide rail, so as to facilitate the installation and disassembly of the wafer under measurement.

[0057] This application adopts the design of a gantry bracket and a rotating motor. The rotating motor does not need to move in the horizontal plane, and the full-area measurement of the wafer under test is achieved by polar coordinate movement. This design separates the rotating axis used for the circumferential movement of the wafer and the linear axis for radial movement, avoiding the stacking of two moving spindles and reducing errors caused by insufficient assembly accuracy.

[0058] In this application, the drive, control, acquisition and other related hardware are arranged at the bottom and tail of the gantry bracket, so that the structure of the device is compact and the space volume is very small. While meeting the measurement needs of large-size wafers, it also takes into account the lightweight and miniaturization requirements of the device, realizing a desktop-level design of the measuring device.

[0059] It should be understood that expressions such as "including" and "may include" that may be used in the present 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 the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding 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 the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. 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] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which 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, which 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 is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection 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, the interior is an air path cavity, and the upper surface is processed with air suction holes so that the wafer to be tested can be fixed by air suction; the probe linear module is installed on the linear guide rail; The rotary motor is used to drive the loading platform to rotate, so as to realize the switching of the points in the circumferential direction of the wafer under test; the linear guide is used to drive the probe linear module to move along the radial direction of the wafer under test, so as to realize the switching of the points in the radial direction; the probe linear module drives the coil probe in the data acquisition module to move in the direction perpendicular to the wafer under test, so as to adjust the distance between the coil probe and the wafer under test; The data acquisition module includes a distance sensor and a coil probe; the distance sensor is used to measure the distance between the wafer to be tested and the coil probe in real time; the coil probe is used to measure the resistance of each measuring point of the wafer to be tested under the action of current.

2. The non-contact wafer resistance measuring device according to claim 1, characterized in that: Also includes: Human-machine interaction interface, drive control module and power supply module; The output current source in the power supply module and the 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 in the drive control module and the motion control board are installed in the tail box, and an external interface for a human-machine interaction interface is provided in the tail box; The human-computer interaction interface is used for parameter setting, path planning for wafer testing, and display and storage of 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 for the coil probe; Motor drivers are used to drive and control rotating motors; The motion control board is used to control the motion of the probe linear module according to the set target distance value; The power supply module is used to provide 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 installed on the probe linear module; a coil probe is arranged below the probe fixing support, and a distance sensor is installed on the side end of the coil probe; the bracket is installed on the bottom box, and a linear guide rail is installed on the bracket.

4. A measurement method based on the non-contact wafer resistance measurement device according to claim 1, characterized in that: The following steps are involved: Step 1: Use a linear guide to drive the probe linear module and the coil probe to move to the center of the loading platform. When the center of the coil probe coincides with the center of the loading platform, the position of the linear guide is used as the zero position of the measurement; Step 2: Move the linear guide rail to the side, and at the same time 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 rail 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 a first set value; Step 3: Move the coil probe to the current measuring point, suspend the linear guide and the rotary motor, and use the probe linear module to adjust the spacing to the second set value; Step 4: Measure the resistance value of the wafer under test at the current measuring point.

5. The measuring method according to claim 4, characterized in that: The following steps are also included: The switching of different measuring points of the wafer under test in the radial direction and the circumferential direction is respectively realized by the movement of the linear guide and the rotary motor, and then the process goes to step 3 until the resistance values ​​of all the measuring points are obtained.

6. The measuring method according to claim 4 or 5, characterized in that: The method of replacing different wafers under test is: Move the probe linear module to the top, so that the coil probe is away from the current wafer to be tested, and replace a different wafer to be tested.

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

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