A gsg probe contact pressure measurement method and system

Abstract

The application relates to the technical field of workpiece measurement, and discloses a GSG probe contact pressure measurement method and system, which comprises the following steps: collecting output voltages generated by a double-cantilever pressure monitoring unit due to measurement pressure; constructing a pressure-voltage mapping relationship of a measurement cantilever based on the output voltages, and calculating a pressure difference measured by two measurement cantilevers based on the pressure-voltage mapping relationship; constructing an inclination angle calculation model based on the pressure difference, determining a measurement inclination angle of a GSG probe assembly when the GSG probe assembly measures a device to be measured through the inclination angle calculation model; obtaining the measurement inclination angle, and adjusting the GSG probe assembly and the surface of the device to be measured to keep vertical based on the measurement inclination angle; obtaining final output voltages of the two measurement cantilevers after the GSG probe assembly is kept vertical to the surface of the device to be measured, and calculating a final pressure based on the final output voltages as the measurement pressure of the GSG probe; the application solves the problem of poor measurement pressure accuracy of the existing GSG probe pressure measurement method.

Description

Technical Field

[0001] This invention relates to the field of workpiece measurement technology, and in particular to a method and system for measuring the contact pressure of a GSG probe. Background Technology

[0002] In RF wafer testing and on-chip device testing, the Ground-Signal-Ground (GSG) probe, driven by a z-axis drive device, contacts the device under test (DUT). The contact pressure between the probe tip and the device surface reflects the high-frequency characteristics of the device. Therefore, the probe tip contact pressure directly affects test stability and device characteristics. If the contact pressure between the probe tip and the device surface is too low, it will lead to unstable contact resistance, causing fluctuations in the test signal. Conversely, excessive contact pressure may damage the device's solder pad metal layer or reduce the probe's lifespan. Clearly, the contact state between the probe and the device significantly impacts the testing accuracy of RF devices.

[0003] Currently, semi-automatic or automatic probe stations typically estimate probe contact pressure indirectly through z-axis displacement, controlling the probe pressure by setting the downward stroke or overtravel. However, because the surfaces of devices such as RF wafers often exhibit a frustum or inverse frustum shape (higher in the center and lower at the periphery, or vice versa), this method cannot perceive the actual contact state between the probe and the device surface. Especially when the probe makes non-perpendicular contact due to installation errors or device surface tilt (i.e., when a measurement tilt angle exists), the actual pressure distribution deviates significantly from the pressure under ideal perpendicular conditions. This results in the actual pressure on the device surface being greater than the pressure obtained from the probe, potentially damaging the device surface. Existing methods not only fail to measure this deviation but also cannot effectively correct the tilt angle, leading to inaccurate contact pressure control and consequently affecting test consistency and device safety. Therefore, existing GSG probe pressure measurement methods suffer from poor pressure measurement accuracy. Summary of the Invention

[0004] This invention provides a method and system for measuring the contact pressure of a GSG probe, in order to solve the problem of poor accuracy in measuring pressure in existing GSG probe pressure measurement methods.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, the present invention provides a method for measuring the contact pressure of a GSG probe, applied to a GSG probe contact pressure measurement system. The GSG probe contact pressure measurement system includes: a motion control module, a signal acquisition module, a data processing module, and a monitoring module. The monitoring module includes a GSG probe assembly and a double-cantilever pressure monitoring unit comprising two measuring cantilever arms. The measurement method includes: The motion control module drives the GSG probe assembly and the dual cantilever pressure monitoring unit to come close to the surface of the device under test to generate measurement pressure, and then transmits the measurement pressure to the dual cantilever pressure monitoring unit. The signal acquisition module acquires the output voltage generated by the double cantilever pressure monitoring unit due to the measured pressure, and sends the output voltage to the data processing module. The data processing module constructs a pressure-voltage mapping relationship for the measuring cantilever based on the output voltage, and calculates the pressure difference between the two measuring cantilever arms based on the pressure-voltage mapping relationship. The data processing module constructs an inclination calculation model based on the pressure difference, and the inclination calculation model is used to determine the measurement inclination angle when the GSG probe assembly measures the device under test. The motion control module acquires the measurement tilt angle and adjusts the GSG probe assembly to maintain perpendicularity to the surface of the device under test based on the measurement tilt angle. The signal acquisition module obtains the final output voltage of the two measuring cantilever arms after the GSG probe assembly is perpendicular to the surface of the device under test, and the data processing module calculates the final pressure based on the final output voltage as the measurement pressure of the GSG probe.

[0006] Preferably, constructing the pressure-voltage mapping relationship for the measuring cantilever includes: A first mapping relationship is established between the cantilever deformation displacement and the probe contact force when the GSG probe assembly is attached to the surface of the device under test. The first mapping relationship satisfies the following equation: ; A second mapping relationship between the surface strain and deformation displacement of the cantilever is constructed, wherein the second mapping relationship satisfies the following equation: ; A third mapping relationship between the change in resistance and the surface strain when the strain gauge senses and measures the strain on the cantilever surface is constructed, wherein the third mapping relationship satisfies the following equation: ; A fourth mapping relationship is constructed between the change in strain gauge resistance and the output voltage, wherein the fourth mapping relationship satisfies the following equation: ; Based on the first, second, third, and fourth mapping relationships, pressure-voltage mapping relationships are constructed for two measuring cantilever arms. These pressure-voltage mapping relationships satisfy the following equation: ; In the formula, This indicates the contact force of the probe tip in the probe assembly. This indicates the measurement of deformation displacement at the end of the cantilever. Indicates the measurement of cantilever length. This indicates the measurement of the elastic modulus of the cantilever material. Represents the moment of inertia of the cantilever section. This indicates the measurement of the surface strain of the cantilever. This indicates the distance from the neutral axis of the cantilever to the surface. This represents the change in resistance of the strain gauge. This represents the initial resistance of the strain gauge. This represents the sensitivity coefficient of the strain gauge. Indicates the output voltage. This indicates the excitation voltage of the bridge circuit.

[0007] Preferably, the calculation of the pressure difference between the two measuring cantilever arms based on the pressure-voltage mapping relationship includes: Substitute the first output voltage of the first measuring arm into the pressure-voltage mapping relationship to calculate the first measuring pressure; substitute the second output voltage of the second measuring arm into the pressure-voltage mapping relationship to calculate the second measuring pressure. The difference between the first and second measured pressures is calculated as the pressure difference between the two measuring cantilever arms.

[0008] Preferably, the tilt angle calculation model is constructed based on the pressure difference through the data processing module, including: Based on the equivalent stiffness of the measured cantilever, a mapping equation between pressure and displacement is constructed, where the mapping equation between pressure and displacement satisfies the following relationship: ; Substituting the pressure-displacement mapping equation into the pressure difference calculation yields the tilt angle calculation model based on the pressure difference, where the tilt angle calculation model satisfies the following relationship: ; ; In the formula, This indicates the pressure measured on the cantilever. This indicates the equivalent stiffness of the cantilever being measured. This indicates the displacement of the cantilever being measured. This indicates the distance from the center of the cantilever to the center line of the probe. Indicates the measured tilt angle. Indicates pressure difference, This indicates the pressure on the first measuring cantilever. This indicates the pressure of the second measuring cantilever.

[0009] Preferably, adjusting the GSG probe assembly to maintain its perpendicularity to the surface of the device under test based on the measurement tilt angle includes: The displacement difference between the first and second measuring cantilever arms is calculated based on the measured tilt angle, where the calculation of the displacement difference satisfies the following relationship: ; In the formula, This represents the displacement difference between the first and second measuring cantilever arms. This indicates the distance from the center of the cantilever to the center line of the probe. Indicates the measured tilt angle; The movement distance between the GSG probe assembly and the double cantilever pressure monitoring unit is adjusted according to the displacement difference, and when the adjusted displacement difference is 0, the GSG probe assembly is determined to be perpendicular to the surface of the device under test.

[0010] In a second aspect, the present invention also provides a GSG probe contact pressure measurement system for performing the steps of any of the GSG probe contact pressure measurement methods in the first aspect. The GSG probe contact pressure measurement system includes: a motion control module, a signal acquisition module, a data processing module, and a monitoring module. The monitoring module includes a GSG probe assembly and a double cantilever pressure monitoring unit comprising two measuring cantilever arms. The GSG probe assembly is used to attach to the surface of the device under test to generate measurement pressure and transmit the measurement pressure to the dual cantilever pressure monitoring unit. The dual-cantilever pressure monitoring unit, fixed to the GSG probe assembly, is used to generate an output voltage based on the measured pressure and send the output voltage to the signal acquisition module. The signal acquisition module is used to acquire the output voltage of the double cantilever pressure monitoring unit and send the output voltage to the data processing module; The data processing module is used to construct a pressure-voltage mapping relationship based on the output voltage, and to determine the pressure difference between the two measuring cantilever arms in the dual cantilever pressure monitoring unit based on the pressure-voltage mapping relationship; it is also used to construct an inclination angle calculation model based on the pressure difference, determine the measurement inclination angle when the GSG probe assembly measures the device under test through the inclination angle calculation model, and send the measurement inclination angle to the motion control module. The motion control module, fixed to the dual cantilever pressure monitoring unit, is used to move the GSG probe assembly and the dual cantilever pressure monitoring unit, and also to adjust the position of the GSG probe assembly and the dual cantilever pressure monitoring unit according to the measurement tilt angle. The signal acquisition module is also used to acquire the final output voltage of the two measurement cantilever arms after the GSG probe assembly is perpendicular to the surface of the device under test; the data processing module is also used to calculate the final pressure based on the final output voltage as the measurement pressure of the GSG probe.

[0011] Preferably, the GSG probe assembly includes: a probe card and a first probe, a second probe, and a third probe fixed on the same plane as the probe card, wherein the sides of the first probe, the second probe, and the third probe away from the probe card are all located on the same plane.

[0012] Preferably, the dual-cantilever pressure monitoring unit includes: a first measuring cantilever and a second measuring cantilever, one end of which is fixed to the GSG probe assembly, and the other end of which is fixed to the motion control module.

[0013] Preferably, the motion control module includes a motion platform and a parallel three-push-rod mechanism, with one side of the motion platform fixed to the double cantilever pressure monitoring unit and the other side connected to the parallel three-push-rod mechanism.

[0014] Preferably, the measurement system further includes a monitoring and display module, which is used to acquire the measurement pressure of the GSG probe in the data processing module in real time and display the measurement pressure of the GSG probe in a graphical and / or curve manner.

[0015] Beneficial effects: The GSG probe contact pressure measurement method provided by this invention integrates a GSG probe assembly and a dual-cantilever pressure monitoring unit. It utilizes a signal acquisition module to acquire the output voltage generated by the pressure on the cantilever, and based on a constructed pressure-voltage mapping relationship, directly converts the output voltage into probe contact force. This achieves real-time, quantitative measurement of contact pressure, overcoming the limitations of traditional methods that rely on indirect estimation based on stroke. Using the pressure difference output by the dual-cantilever structure, a tilt angle calculation model is constructed to accurately calculate the measurement tilt angle between the GSG probe assembly and the surface of the device under test. The motion control module automatically adjusts the posture of the probe assembly according to this tilt angle, ensuring that the probe remains perpendicular to the device surface. This closed-loop control mechanism effectively eliminates pressure measurement errors caused by tilt angle, significantly improving test repeatability and reliability. After tilt angle correction, the final pressure is calculated based on the final output voltage acquired in the vertical state. This pressure truly reflects the vertical contact force between the probe and the device. By precisely controlling this pressure within the optimal range, signal fluctuations caused by insufficient pressure are avoided, as well as damage to the device pads or the probe itself caused by excessive pressure. This ensures test accuracy while protecting the integrity of the device and probe. Attached Figure Description

[0016] Figure 1 This is a flowchart of a preferred embodiment of the GSG probe contact pressure measurement method of the present invention; Figure 2 This is a schematic diagram of the GSG probe contact pressure measurement system according to a preferred embodiment of the present invention; In the figure, 1. GSG probe assembly; 11. First probe; 12. Second probe; 13. Third probe; 14. Probe card; 2. Double cantilever pressure detection unit; 21. First measuring cantilever; 22. Second measuring cantilever; 3. Motion control module; 31. Motion platform; 32. Parallel three-push rod mechanism; 4. Signal acquisition module; 5. Data processing module; 6. Monitoring and display module. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0019] Please see Figures 1-2 This application provides a method for measuring the contact pressure of a GSG probe, applied to a GSG probe contact pressure measurement system. The GSG probe contact pressure measurement system includes: a motion control module 3, a signal acquisition module 4, a data processing module 5, and a monitoring module. The monitoring module includes a GSG probe assembly 1 and a double-cantilever pressure monitoring unit 2 containing two measuring cantilever arms. The measurement method includes: The motion control module drives the GSG probe assembly and the dual cantilever pressure monitoring unit to come close to the surface of the device under test to generate measurement pressure, and then transmits the measurement pressure to the dual cantilever pressure monitoring unit. The signal acquisition module acquires the output voltage generated by the double cantilever pressure monitoring unit due to the measured pressure, and sends the output voltage to the data processing module. The data processing module constructs a pressure-voltage mapping relationship for the measuring cantilever based on the output voltage, and calculates the pressure difference between the two measuring cantilever arms based on the pressure-voltage mapping relationship. The data processing module constructs an inclination calculation model based on the pressure difference, and the inclination calculation model is used to determine the measurement inclination angle when the GSG probe assembly measures the device under test. The motion control module acquires the measurement tilt angle and adjusts the GSG probe assembly to maintain perpendicularity to the surface of the device under test based on the measurement tilt angle. The signal acquisition module obtains the final output voltage of the two measuring cantilever arms after the GSG probe assembly is perpendicular to the surface of the device under test, and the data processing module calculates the final pressure based on the final output voltage as the measurement pressure of the GSG probe.

[0020] In the above embodiment, the monitoring module, integrating the GSG probe assembly 1 and the dual cantilever pressure monitoring unit 2, measures the pressure on the device surface. First, the motion control module moves the probe close to the surface of the device under test, generating measurement pressure. This pressure causes deformation of the dual cantilever arms, and the signal acquisition module collects the output voltage generated by the deformation. The data processing module constructs a pressure-voltage mapping relationship based on the output voltage, directly converting the electrical signal into actual contact force, achieving real-time quantitative measurement of the probe pressure and avoiding errors caused by indirect estimation based on z-axis travel in traditional methods. Furthermore, a tilt angle calculation model is constructed by calculating the pressure difference between the two measuring cantilever arms, accurately identifying the non-perpendicular tilt angle between the probe assembly and the device surface. The motion control module automatically adjusts the probe posture according to this tilt angle until it remains perpendicular, and then collects the final output voltage in the perpendicular state to calculate the final pressure. This closed-loop process not only eliminates pressure measurement deviations caused by tilt angles but also ensures that the final measured pressure truly reflects the vertical contact force. It prevents signal fluctuations caused by insufficient pressure and avoids damage to the device or probe caused by excessive pressure, significantly improving test accuracy, repeatability, and device safety.

[0021] Preferably, constructing the pressure-voltage mapping relationship for the measuring cantilever includes: A first mapping relationship is established between the cantilever deformation displacement and the probe contact force when the GSG probe assembly is attached to the surface of the device under test. The first mapping relationship satisfies the following equation: ; A second mapping relationship between the surface strain and deformation displacement of the cantilever is constructed, wherein the second mapping relationship satisfies the following equation: ; A third mapping relationship between the change in resistance and the surface strain when the strain gauge senses and measures the strain on the cantilever surface is constructed, wherein the third mapping relationship satisfies the following equation: ; A fourth mapping relationship is constructed between the change in strain gauge resistance and the output voltage, wherein the fourth mapping relationship satisfies the following equation: ; Based on the first, second, third, and fourth mapping relationships, pressure-voltage mapping relationships are constructed for two measuring cantilever arms. These pressure-voltage mapping relationships satisfy the following equation: ; In the formula, This indicates the contact force of the probe tip in the probe assembly. This indicates the measurement of deformation displacement at the end of the cantilever. Indicates the measurement of cantilever length. This indicates the measurement of the elastic modulus of the cantilever material. Represents the moment of inertia of the cantilever section. This indicates the measurement of the surface strain of the cantilever. This indicates the distance from the neutral axis of the cantilever to the surface. This represents the change in resistance of the strain gauge. This represents the initial resistance of the strain gauge. This represents the sensitivity coefficient of the strain gauge. Indicates the output voltage. This indicates the excitation voltage of the bridge circuit.

[0022] In the above embodiments, by sequentially establishing a first mapping relationship between cantilever deformation displacement and probe contact force, a second mapping relationship between surface strain and deformation displacement, a third mapping relationship between strain gauge resistance change and surface strain, and a fourth mapping relationship between resistance change and output voltage, a concise pressure-voltage linear relationship is finally obtained. The establishment of this mapping relationship allows the output voltage to be directly and accurately converted into probe tip contact force without complex intermediate calibration or empirical estimation. This ensures the accuracy and traceability of the measurement results from a physical perspective, providing a reliable data foundation for subsequent pressure difference calculation and tilt angle correction.

[0023] Preferably, the calculation of the pressure difference between the two measuring cantilever arms based on the pressure-voltage mapping relationship includes: Substitute the first output voltage of the first measuring arm into the pressure-voltage mapping relationship to calculate the first measuring pressure; substitute the second output voltage of the second measuring arm into the pressure-voltage mapping relationship to calculate the second measuring pressure. The difference between the first and second measured pressures is calculated as the pressure difference between the two measuring cantilever arms.

[0024] In the above embodiment, by substituting the first output voltage from the first measuring cantilever and the second output voltage from the second measuring cantilever into the established pressure-voltage mapping relationship, the corresponding first and second measured pressures are obtained, and then the difference between the two is calculated as the pressure difference. This process utilizes the symmetry of the double cantilever structure to differentially process the pressure measurement results of the two independent cantilever arms, which can effectively cancel common-mode interference, such as changes in ambient temperature and initial system offset, and retain only the pressure difference caused by probe tilt angle or device surface tilt. This provides high signal-to-noise ratio input parameters for the subsequent tilt angle calculation model, improving the sensitivity and anti-interference capability of tilt angle detection.

[0025] Preferably, the tilt angle calculation model is constructed based on the pressure difference through the data processing module, including: Based on the equivalent stiffness of the measured cantilever, a mapping equation between pressure and displacement is constructed, where the mapping equation between pressure and displacement satisfies the following relationship: ; Substituting the pressure-displacement mapping equation into the pressure difference calculation yields the tilt angle calculation model based on the pressure difference, where the tilt angle calculation model satisfies the following relationship: ; ; In the formula, This indicates the pressure measured on the cantilever. This indicates the equivalent stiffness of the cantilever being measured. This indicates the displacement of the cantilever being measured. This indicates the distance from the center of the cantilever to the center line of the probe. Indicates the measured tilt angle. Indicates pressure difference, This indicates the pressure on the first measuring cantilever. This indicates the pressure of the second measuring cantilever.

[0026] In the above embodiment, a mapping equation between pressure and displacement is first established based on the equivalent stiffness of the cantilever. This equation reflects the displacement difference between the two cantilever arms due to their different positions when an inclination angle exists. Subtracting the pressure expressions of the two cantilever arms yields the pressure difference. This model directly transforms the abstract pressure difference into a quantifiable geometric inclination angle, with clear physical meaning and simple calculation. Through this model, the system can obtain the relative tilt degree between the probe and the device surface in real time and quantitatively, providing a crucial feedback quantity for achieving automatic vertical correction and solving the problem that traditional probe stations cannot sense and quantify inclination angles.

[0027] Preferably, adjusting the GSG probe assembly to maintain its perpendicularity to the surface of the device under test based on the measurement tilt angle includes: The displacement difference between the first and second measuring cantilever arms is calculated based on the measured tilt angle, where the calculation of the displacement difference satisfies the following relationship: ; In the formula, This represents the displacement difference between the first and second measuring cantilever arms. This indicates the distance from the center of the cantilever to the center line of the probe. Indicates the measured tilt angle; The movement distance between the GSG probe assembly and the double cantilever pressure monitoring unit is adjusted according to the displacement difference, and when the adjusted displacement difference is 0, the GSG probe assembly is determined to be perpendicular to the surface of the device under test.

[0028] In the above embodiment, the displacement difference between the first and second measuring cantilever arms is calculated based on geometric relationships. This displacement difference directly corresponds to the vertical height difference that the motion control module needs to compensate for. The motion control module then... By adjusting the height of both ends of the dual-cantilever pressure monitoring unit, the displacement difference between the two cantilever arms is gradually reduced to zero. At this point, it can be determined that the probe assembly is perpendicular to the surface of the device under test. This method transforms the tilt correction problem into an executable position adjustment command, which has the advantages of low computational load, fast response, and easy closed-loop control. It ensures that the probe can automatically reach the ideal vertical contact posture before each test, thereby eliminating measurement uncertainties caused by installation errors or fluctuations in the surface morphology of the device.

[0029] This application embodiment also provides a GSG probe contact pressure measurement system for performing the steps of any of the GSG probe contact pressure measurement methods. The GSG probe contact pressure measurement system includes: a monitoring module integrating a GSG probe assembly 1 and a double cantilever pressure monitoring unit 2 containing two measuring cantilever arms, a motion control module 3, a signal acquisition module 4, and a data processing module 5. The GSG probe assembly is used to attach to the surface of the device under test to generate measurement pressure and transmit the measurement pressure to the dual cantilever pressure monitoring unit. The dual-cantilever pressure monitoring unit, fixed to the GSG probe assembly, is used to generate an output voltage based on the measured pressure and send the output voltage to the signal acquisition module. The signal acquisition module is used to acquire the output voltage of the double cantilever pressure monitoring unit and send the output voltage to the data processing module; The data processing module is used to construct a pressure-voltage mapping relationship based on the output voltage, and to determine the pressure difference between the two measuring cantilever arms in the dual cantilever pressure monitoring unit based on the pressure-voltage mapping relationship; it is also used to construct an inclination angle calculation model based on the pressure difference, determine the measurement inclination angle when the GSG probe assembly measures the device under test through the inclination angle calculation model, and send the measurement inclination angle to the motion control module. The motion control module, fixed to the dual cantilever pressure monitoring unit, is used to move the GSG probe assembly and the dual cantilever pressure monitoring unit, and also to adjust the position of the GSG probe assembly and the dual cantilever pressure monitoring unit according to the measurement tilt angle. The signal acquisition module is also used to acquire the final output voltage of the two measurement cantilever arms after the GSG probe assembly is perpendicular to the surface of the device under test; the data processing module is also used to calculate the final pressure based on the final output voltage as the measurement pressure of the GSG probe.

[0030] In the above embodiments, the GSG probe contact pressure measurement system integrates a GSG probe assembly, a dual-cantilever pressure monitoring unit, a motion control module, a signal acquisition module, and a data processing module. This system achieves hardware support for the GSG probe contact pressure measurement method through modular division of labor: the probe assembly generates pressure and transmits it to the dual cantilever; the dual cantilever converts the pressure into a measurable output voltage; the signal acquisition module is responsible for accurate voltage acquisition; the data processing module completes pressure-voltage mapping, pressure difference calculation, tilt model construction, and final pressure calculation; and the motion control module performs tilt adjustment and position movement. The modules work collaboratively to form a complete closed loop from pressure sensing, signal conversion, data processing, tilt correction, to vertical measurement. This enables automatic, real-time, and high-precision measurement of the actual contact pressure of the GSG probe, overcoming the shortcomings of traditional probe stations that can only roughly control the downward pressure stroke, and significantly improving the consistency and device safety of RF wafer testing.

[0031] In this embodiment, the signal acquisition module 4 is responsible for picking up, conditioning, and converting the weak electrical signals generated by the deformation of the two measuring cantilever arms in the dual cantilever pressure monitoring unit 2 under stress, and then transmitting them to the data processing module 5. It simultaneously undertakes the tasks of voltage acquisition during initial contact and final voltage acquisition after vertical correction. Each measuring cantilever arm has strain gauges attached to its surface, typically connected in a Wheatstone bridge configuration. When the cantilever arm deforms, the change in strain gauge resistance causes the bridge to become unbalanced, outputting a differential voltage. This differential voltage amplitude is very small, typically in the millivolt range. The signal acquisition module 4 first performs differential amplification using a high-precision instrumentation amplifier, such as an INA333 or AD8429, while simultaneously suppressing common-mode noise to obtain a clear electrical signal, i.e., voltage data.

[0032] Data processing module 5 receives voltage data from the signal acquisition module and performs pressure-voltage mapping, pressure difference calculation, tilt angle model solution, verticality determination, and final pressure calculation. At the hardware level, data processing module 5 can employ an embedded microcontroller, such as the STM32H7 series, a DSP, or an industrial PC. In this embodiment, the hardware of data processing module 5 is merely an example and not limited. During data processing, the real-time data to be processed can be cached using internally integrated non-volatile memory and RAM. Simultaneously, the processed data can also be cached in the hardware for other hardware modules to read.

[0033] Preferably, the GSG probe assembly includes: a probe card and a first probe, a second probe, and a third probe fixed on the same plane as the probe card, wherein the sides of the first probe, the second probe, and the third probe away from the probe card are all located on the same plane.

[0034] In the above embodiment, this design ensures the coplanarity of the three probe tips, resulting in uniform contact pressure between each probe and the device surface under perpendicular contact conditions. This avoids over- or under-pressure issues for individual probes caused by differences in tip height. Furthermore, under non-perpendicular contact conditions, one probe will initially contact the device surface, creating a pressure difference among the three probes at the probe level. Simultaneously, this standard GSG arrangement is compatible with mainstream RF testing requirements, ensuring good shielding and transmission quality for high-frequency signals. The coplanar design also provides a stable force reference for the dual cantilever pressure monitoring unit 2, facilitating the decomposition of the force component of each cantilever from the overall contact force and improving the accuracy of tilt angle detection.

[0035] Preferably, the dual-cantilever pressure monitoring unit includes: a first measuring cantilever and a second measuring cantilever, one end of which is fixed to the GSG probe assembly, and the other end of which is fixed to the motion control module.

[0036] In the above embodiment, the dual-cantilever pressure monitoring unit 2 comprises a first measuring cantilever 21 and a second measuring cantilever 22, both fixed at one end to the GSG probe assembly 1 and at the other end to the motion control module 3. This two-end fixing method allows the contact pressure on the probe assembly to be directly transmitted to the two cantilever arms, and the two cantilever arms are independently stressed and do not interfere with each other. The degree of deformation of the cantilever arms is proportional to the transmitted force, and the deformation can be sensed and converted into an electrical signal by strain gauges attached to the surface of the cantilever arms. This symmetrical arrangement of the dual cantilever arms naturally possesses differential measurement capabilities, which can effectively separate common-mode pressure and differential-mode pressure, providing a direct physical basis for tilt angle calculation. At the same time, the fixing method is simple and reliable, facilitating system integration and long-term stability.

[0037] Preferably, the motion control module includes a motion platform and a parallel three-push-rod mechanism, with one side of the motion platform fixed to the double cantilever pressure monitoring unit and the other side connected to the parallel three-push-rod mechanism.

[0038] In the above embodiment, the motion control module 3 includes a motion platform 31 and a parallel three-push-rod mechanism 32. The double cantilever pressure monitoring unit 2 is fixed on one side of the motion platform 31, and the parallel three-push-rod mechanism 32 is connected to the other side. The parallel three-push-rod mechanism 32 can achieve high-precision three-dimensional translation and tilt adjustment, and is especially suitable for completing the required displacement difference compensation action. That is, by independently controlling the extension and retraction of the three push rods, the pitch and roll angles of the motion platform 31 can be precisely adjusted, so that the double cantilever pressure monitoring unit 2 and the GSG probe assembly 1 fixed on it are tilted as a whole until the displacement difference between the two cantilever arms is zero, that is, verticality is achieved. Each pusher of the parallel three-push-rod mechanism 32 is controlled by a stepper motor, which in turn is controlled by a built-in control unit. During the first measurement, the control unit does not obtain the measurement tilt angle from the data processing module 5, so it controls all stepper motors to maintain the same speed and rotational magnitude. At this time, the pushing distance of the three pushers is the same. After the data processing module 5 determines the measurement tilt angle based on the pressure difference between the two measuring cantilever arms, the control unit can determine the current tilt angle of the probe relative to the device surface and the displacement difference between the two measuring cantilever arms based on the measurement tilt angle. It can then control the stepper motors again based on the displacement difference, allowing the movement distance of the three pushers to compensate for the displacement difference. This completes the adjustment of the probe, ensuring it remains perpendicular to the device surface. Compared to traditional single-axis or dual-axis adjustment mechanisms, the parallel three-push-rod mechanism has advantages such as high rigidity, no cumulative error, and fast response speed. It can quickly complete micron-level or even sub-micron-level attitude correction, ensuring the accuracy and efficiency of tilt angle adjustment.

[0039] Preferably, the measurement system further includes a monitoring and display module, which is used to acquire the measurement pressure of the GSG probe in the data processing module in real time and display the measurement pressure of the GSG probe in a graphical and / or curve manner.

[0040] In the above embodiment, this module acquires the measured pressure of the GSG probe in the data processing module in real time and displays it graphically and / or as a curve. This function provides operators with an intuitive means of monitoring the testing process: by observing the pressure curve, operators can determine in real time whether the probe contact is stable, whether there are pressure shocks or fluctuations, and whether the set target pressure range has been reached. Combined with the tilt correction process, it can also display the pressure changes before and after correction, facilitating the verification of system effectiveness. At the same time, the graphical display helps to quickly identify abnormal situations, such as a sudden pressure rise indicating possible overpressure, thereby enabling timely intervention to protect the device and probe. The addition of this module improves the human-machine interaction capability of the measurement system and enhances the traceability of the test and the convenience of data analysis.

[0041] The monitoring and display module 6 acquires the GSG probe measurement pressure calculated by the data processing module 5 in real time and displays it to the operator graphically, such as real-time curves, digital instruments, bar charts, and / or text. It can also assist in process monitoring, data recording, and anomaly alarms. The monitoring and display module 6 can be an industrial touchscreen integrated into the probe station or an external PC / laptop. When displaying the measured pressure in real time, the monitoring and display module 6 can pop up a window with an audible and visual alarm when the pressure exceeds a preset threshold or tilt correction fails. Simultaneously, during tilt correction, it can dynamically display... The changing trends help operators intuitively understand the adjustment process.

[0042] In this embodiment, when monitoring the measurement pressure in real time, different state functions can be defined to monitor the probe's measurement status in real time. During the monitoring process, a maximum pressure contact threshold is defined. And utilize the combined force of the first measuring cantilever and the second measuring cantilever. The pressure difference between the first measuring cantilever and the second measuring cantilever And measuring the torque of the cantilever. A comprehensive assessment of the contact state and tilt direction is made.

[0043] ; ; ; Controlling the Z-axis vertical downward pressure, if the probe is in a horizontal state, that is, during the probe's downward pressure, all three needles simultaneously contact the workpiece, no torque is generated. =0 and Due to data measurement and acquisition errors, in this example, and Not entirely zero, but should satisfy: ; ; In the formula, The force difference tolerance is determined by noise plus systematic error. ; Controlling the vertical downward pressure along the Z-axis, assuming the probe is tilted to the right, the right tip of the probe contacts the workpiece first, generating a torque M, and .

[0044] The monitoring results corresponding to the state function are shown in Table 1 below.

[0045] Table 1: Monitoring Results Corresponding to State Functions

[0046] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for measuring the contact pressure of a GSG probe, applied to a GSG probe contact pressure measurement system, the GSG probe contact pressure measurement system comprising: The system comprises a motion control module, a signal acquisition module, a data processing module, and a monitoring module, characterized in that the monitoring module includes a GSG probe assembly and a dual-cantilever pressure monitoring unit containing two measuring cantilever arms, and the measurement method includes: The motion control module drives the GSG probe assembly and the dual cantilever pressure monitoring unit to come close to the surface of the device under test to generate measurement pressure, and then transmits the measurement pressure to the dual cantilever pressure monitoring unit. The signal acquisition module acquires the output voltage generated by the double cantilever pressure monitoring unit due to the measured pressure, and sends the output voltage to the data processing module. The data processing module constructs a pressure-voltage mapping relationship for the measuring cantilever based on the output voltage, and calculates the pressure difference measured by the two measuring cantilever based on the pressure-voltage mapping relationship. The data processing module constructs an angle calculation model based on the pressure difference, and the angle calculation model is used to determine the measurement angle of the GSG probe assembly when measuring the device under test. The measurement tilt angle is obtained through the motion control module, and the GSG probe assembly is adjusted to be perpendicular to the surface of the device under test based on the measurement tilt angle. The signal acquisition module obtains the final output voltage of the two measuring cantilever arms after the GSG probe assembly is perpendicular to the surface of the device under test, and the data processing module calculates the final pressure based on the final output voltage as the measurement pressure of the GSG probe.

2. The GSG probe contact pressure measurement method according to claim 1, characterized in that, Constructing the pressure-voltage mapping relationship for the measuring cantilever includes: A first mapping relationship is established between the cantilever deformation displacement and the probe contact force when the GSG probe assembly is attached to the surface of the device under test. The first mapping relationship satisfies the following equation: ； A second mapping relationship between the surface strain and deformation displacement of the cantilever is constructed, wherein the second mapping relationship satisfies the following equation: ； A third mapping relationship between the change in resistance and the surface strain when the strain gauge senses and measures the strain on the cantilever surface is constructed, wherein the third mapping relationship satisfies the following equation: ； A fourth mapping relationship is constructed between the change in strain gauge resistance and the output voltage, wherein the fourth mapping relationship satisfies the following equation: ； Based on the first, second, third, and fourth mapping relationships, pressure-voltage mapping relationships are constructed for two measuring cantilever arms. These pressure-voltage mapping relationships satisfy the following equation: ； In the formula, This indicates the contact force of the probe tip in the probe assembly. This indicates the measurement of deformation displacement at the end of the cantilever. Indicates the measurement of cantilever length. This indicates the measurement of the elastic modulus of the cantilever material. Represents the moment of inertia of the cantilever section. This indicates the measurement of the surface strain of the cantilever. This indicates the distance from the neutral axis of the cantilever to the surface. This represents the change in resistance of the strain gauge. This represents the initial resistance of the strain gauge. This represents the sensitivity coefficient of the strain gauge. Indicates the output voltage. This indicates the excitation voltage of the bridge circuit.

3. The GSG probe contact pressure measurement method according to claim 2, characterized in that, Calculating the pressure difference between the two measuring cantilever arms based on the pressure-voltage mapping relationship includes: Substitute the first output voltage of the first measuring arm into the pressure-voltage mapping relationship to calculate the first measuring pressure; substitute the second output voltage of the second measuring arm into the pressure-voltage mapping relationship to calculate the second measuring pressure. The difference between the first measured pressure and the second measured pressure is calculated as the pressure difference between the two measuring cantilever arms.

4. The GSG probe contact pressure measurement method according to claim 1, characterized in that, The data processing module constructs an inclination calculation model based on the pressure difference, including: Based on the equivalent stiffness of the measured cantilever, a mapping equation between pressure and displacement is constructed, where the mapping equation between pressure and displacement satisfies the following relationship: ； Substituting the pressure-displacement mapping equation into the pressure difference calculation yields the tilt angle calculation model based on the pressure difference, where the tilt angle calculation model satisfies the following relationship: ； ； In the formula, This indicates the pressure measured on the cantilever. This indicates the equivalent stiffness of the cantilever being measured. This indicates the displacement of the cantilever being measured. This indicates the distance from the center of the cantilever to the center line of the probe. Indicates the measured tilt angle. Indicates pressure difference, This indicates the pressure on the first measuring cantilever. This indicates the pressure of the second measuring cantilever.

5. The GSG probe contact pressure measurement method according to claim 1, characterized in that, Adjusting the GSG probe assembly to maintain its perpendicularity to the surface of the device under test based on the measurement tilt angle includes: The displacement difference between the first and second measuring cantilever arms is calculated based on the measured tilt angle, wherein the calculation of the displacement difference satisfies the following relationship: ； In the formula, This represents the displacement difference between the first and second measuring cantilever arms. This indicates the distance from the center of the cantilever to the center line of the probe. Indicates the measured tilt angle; The moving distance between the GSG probe assembly and the double cantilever pressure monitoring unit is adjusted according to the displacement difference, and when the adjusted displacement difference is 0, it is determined that the GSG probe assembly remains perpendicular to the surface of the device under test.

6. A GSG probe contact pressure measurement system for performing the steps of the GSG probe contact pressure measurement method as described in any one of claims 1-5, the GSG probe contact pressure measurement system comprising: The motion control module, signal acquisition module, data processing module, and monitoring module are characterized in that the monitoring module includes a GSG probe assembly and a double cantilever pressure monitoring unit containing two measuring cantilever arms. The GSG probe assembly is used to attach to the surface of the device under test to generate measurement pressure and transmit the measurement pressure to the dual cantilever pressure monitoring unit. The dual-cantilever pressure monitoring unit, fixed to the GSG probe assembly, is used to generate an output voltage based on the measured pressure and send the output voltage to the signal acquisition module. The signal acquisition module is used to acquire the output voltage of the double cantilever pressure monitoring unit and send the output voltage to the data processing module; The data processing module is used to construct a pressure-voltage mapping relationship based on the output voltage, and to determine the pressure difference between the two measuring cantilever arms in the dual cantilever pressure monitoring unit based on the pressure-voltage mapping relationship; it is also used to construct an inclination angle calculation model based on the pressure difference, determine the measurement inclination angle when the GSG probe assembly measures the device under test through the inclination angle calculation model, and send the measurement inclination angle to the motion control module. The motion control module, fixed to the dual cantilever pressure monitoring unit, is used to move the GSG probe assembly and the dual cantilever pressure monitoring unit, and also to adjust the position of the GSG probe assembly and the dual cantilever pressure monitoring unit according to the measurement tilt angle. The signal acquisition module is also used to acquire the final output voltage of the two measuring cantilever arms after the GSG probe assembly is perpendicular to the surface of the device under test; the data processing module is also used to calculate the final pressure based on the final output voltage as the measuring pressure of the GSG probe.

7. The GSG probe contact pressure measurement system according to claim 6, characterized in that, The GSG probe assembly includes: a probe card and a first probe, a second probe, and a third probe fixed on the same plane as the probe card, wherein the first probe, the second probe, and the third probe are all located on the same plane on the side away from the probe card.

8. The GSG probe contact pressure measurement system according to claim 6, characterized in that, The dual-cantilever pressure monitoring unit includes a first measuring cantilever and a second measuring cantilever, one end of which is fixed to the GSG probe assembly, and the other end of which is fixed to the motion control module.

9. The GSG probe contact pressure measurement system according to claim 6, characterized in that, The motion control module includes a motion platform and a parallel three-push rod mechanism. One side of the motion platform is fixed to the double cantilever pressure monitoring unit, and the other side is connected to the parallel three-push rod mechanism.

10. The GSG probe contact pressure measurement system according to claim 6, characterized in that, The measurement system further includes a monitoring and display module, which is used to acquire the measurement pressure of the GSG probe in the data processing module in real time and display the measurement pressure of the GSG probe in a graphical and / or curve manner.

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