Radio frequency probe full-automatic regulation and control method and system based on scattering parameter change

Abstract

The application provides a full-automatic control method and system of a radio frequency probe based on scattering parameter change, comprising: acquiring scattering parameters of three contact pads of GSG three contacts relative to three contact pads in real time in the process of alignment of probe relative to wafer electrode touch plate movement; performing leveling operation of the probe according to the polar coordinate diagram position of the scattering parameters, comprising: adjusting the angle θ of the GSG three contact line relative to the plane of the electrode touch plate according to the polar coordinate diagram position of the scattering parameters, so that the GSG three contact line is parallel to the plane of the electrode touch plate; performing alignment operation of the three-dimensional position of the probe according to the real part value change of the scattering parameters, comprising: adjusting the position of the GSG three contacts relative to the XYZ axis of the three contact pads according to the real part value change of the scattering parameters, so that the GSG three contacts are respectively in contact with the three contact pads. The application realizes automatic fine control of the probe in X, Y, Z and θ four directions, so as to improve the alignment accuracy, repeatability and measurement accuracy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductor radio frequency microwave test, and relates to a radio frequency probe full-automatic regulation method and system based on scattering parameter change. BACKGROUND

[0002] Precise wafer test technology mainly realizes parameter measurement and precision calibration procedures based on a probe station, and is a key step in the integrated circuit (IC) design and debugging process. In the semiconductor industry and related research fields, a wafer test probe station is currently a mature tool for testing circuits and devices on a wafer, and a manual probe station is currently more commonly used.

[0003] However, in actual testing, especially in the field of metrology, more attention is paid to measurement accuracy, universality and scalability. On the one hand, when using a manual probe station, an operator needs to observe the probe head profile through a microscope to infer the position of the probe tip GSG contact, and manually align the probe with the chip contact pad. However, different operators have certain differences in judging the probe head profile, and during the chip on-die measurement process, the probe tip may be fatigued and deformed due to the long-term stress applied to the probe tip, causing the position of the probe head profile relative to the probe tip GSG contact to change. Therefore, between new probes and old probes, even if the same operator observes that the probe head profile is completely aligned at the same position, the position of the probe tip contact will be different. In addition, according to different probe manufacturers and models, there are significant differences in the relative position between the probe head profile and the probe tip.

[0004] On the other hand, in a traditional test system, the probe tilt angle is determined by an operator adjusting the probe tip through a microscope and observing the footprint left by the probe tip on a leveling sheet. When using a GSG probe, the operator adjusts the tilt angle until three symmetrical and identical footprints are obtained on the leveling sheet. However, the range of angles at which all probe tips can effectively contact the pad varies due to probe sliding, and the accuracy of adjustment depends largely on the changes in probe sliding, while the contact pad and the probe tip are often not clear enough under the microscope, affecting judgment. Based on the above reasons, in the current metrology method based on a manual probe station, there are problems such as unsatisfactory alignment accuracy, limited repeatability, and inaccurate measurement results.

[0005] Therefore, how to provide a radio frequency probe full-automatic regulation method and system with high alignment accuracy, repeatability and measurement accuracy is a problem that those skilled in the art need to solve. SUMMARY

[0006] Therefore, the application provides a radio frequency probe full-automatic regulation and control method and system based on scattering parameter change.

[0007] In order to achieve the above object, the application adopts the following technical scheme:

[0008] The application discloses a radio frequency probe full-automatic regulation and control method based on scattering parameter change.

[0009] In the process of probe alignment relative to the wafer electrode contact plate, scattering parameters of the three GSG contacts relative to the three contact pads are acquired in real time.

[0010] The leveling operation of the probe is performed according to the polar coordinate position of the scattering parameter, including: the angle θ between the GSG three-contact line and the plane of the electrode contact plate is regulated according to the polar coordinate position of the scattering parameter, so that the GSG three-contact line is parallel to the plane of the electrode contact plate.

[0011] The three-dimensional position alignment operation of the probe is performed according to the real part value change of the scattering parameter, including: the XYZ axis position of the GSG three contacts relative to the three contact pads is regulated according to the real part value change of the scattering parameter, so that the GSG three contacts are respectively in contact with the three contact pads.

[0012] Preferably, the leveling operation of the probe is performed according to the amplitude change of the scattering parameter, including: whether the amplitude of the scattering parameter is 1 and located in the second quadrant of the polar coordinate graph is judged in real time, if yes, the GSG three-contact line is parallel to the plane of the wafer electrode contact plate, and the leveling operation is ended.

[0013] Preferably, the three-dimensional position alignment operation of the probe is performed according to the real part value change of the scattering parameter, including: whether the real part value of the scattering parameter appears an abrupt increase signal is judged in real time, the change amplitude of the abrupt increase signal is greater than a preset value, if yes, the GSG three contacts are respectively in contact with the three contact pads, and the three-dimensional position alignment operation is ended.

[0014] Preferably, the regulation and control coordinate system is that the Z axis is perpendicular to the electrode contact plate direction, and the XOY plane is parallel to the plane of the electrode contact plate; the leveling operation of the probe is performed according to the amplitude change of the scattering parameter, including:

[0015] S11: adjusting the probe to an initial position, the initial position being that the three contacts of the GSG are located in the positive direction of the Z axis of the electrode pad and in the XOY plane in the corresponding position range relative to the three contact pads;

[0016] S12: controlling the probe to move step by step downward along the Z axis according to a preset step distance, and recording the amplitude of the scattering parameter in real time, if the amplitude of the scattering parameter is 1 and located in the second quadrant of the polar coordinate diagram, recording as a first state, entering S13; if the amplitude of the scattering parameter is less than 1, recording as a second state, entering S14; if the amplitude of the scattering parameter is 1 and located in the fourth quadrant of the polar coordinate diagram, recording as a third state, entering S15;

[0017] S13: tilting the probe according to a preset step angle until the scattering parameter enters the second state, recording the angle of the included angle θ as A1; tilting the probe in the reverse direction according to a preset step angle until the scattering parameter enters the second state again, recording the angle of the included angle θ as A2, entering S16;

[0018] S14: determining the side where the contact not contacting the contact pad is located, tilting the probe along the direction of the side according to a preset step angle until the scattering parameter enters the first state, recording the angle of the included angle θ as A1; continuing to tilt the probe according to a preset step angle until the scattering parameter enters the second state again, recording the angle of the included angle θ as A2, entering S16;

[0019] S15: determining the number of contacts not contacting the contact pad, if 0, returning to S12; if 1, returning to S14;

[0020] S16: setting a target angle as the average value between A1 and A2, and adjusting the included angle θ between the line connecting the three contacts of the GSG and the plane where the electrode pad is located to the target angle, completing the leveling operation.

[0021] Preferably, the alignment operation of the initial position in S11 is performed according to the real part value change of the scattering parameter.

[0022] Preferably, the coordinate system is that the Z axis is perpendicular to the direction of the electrode pad, the XOY plane is parallel to the plane where the electrode pad is located, the X axis is the arrangement direction of the three contact pads, and the Y axis is the extension direction of the three contact pads on the wafer electrode pad; the alignment operation of the three-dimensional position of the probe is performed according to the real part value change of the scattering parameter, including:

[0023] adjusting the probe to an initial height, the initial height being that the vertical distance between the probe and the wafer electrode pad is a fixed distance value;

[0024] Controlling the probe to move step by step along the Y axis at the initial height according to a preset step distance, after each step is completed, controlling the probe to move downward along the Z axis by the fixed distance value, so that the contact point is in contact with the wafer electrode touch plate, and the scattering parameter is recorded until the real part value of the scattering parameter appears the sharp increase signal;

[0025] Controlling the probe to move step by step along the X axis at the initial height according to a preset step distance, after each step is completed, controlling the probe to move downward along the Z axis by the fixed distance value, so that the contact point is in contact with the wafer electrode touch plate, and the scattering parameter is recorded until the real part value of the scattering parameter appears the sharp increase signal.

[0026] Preferably, the scattering parameters of the three GSG contact points relative to the three contact pads are acquired in real time by using a vector network analyzer; and the calibration step of the vector network analyzer is further included:

[0027] The measured S parameters of the to-be-tested member are measured by using a calibration device;

[0028] The S parameters of the equivalent model of the to-be-tested member in the vector network analyzer are calculated;

[0029] The residual error between the measured S parameters and the equivalent model S parameters is minimized by using a nonlinear least square algorithm.

[0030] The application further discloses a radio frequency probe full-automatic regulation and control system based on the radio frequency probe full-automatic regulation and control method based on scattering parameter change.

[0031] The vector network analyzer is connected with the probe, and is used for acquiring the scattering parameters of the three GSG contact points relative to the three contact pads in real time in the process that the probe is moved to be aligned relative to the wafer electrode touch plate;

[0032] The regulation and control module is connected with the vector network analyzer, and is used for generating the leveling operation instruction of the probe according to the polar coordinate position of the scattering parameter, including generating the leveling operation instruction that the included angle θ between the three GSG contact point lines and the plane where the electrode touch plate is located is controlled so that the three GSG contact point lines are parallel to the plane where the electrode touch plate is located according to the polar coordinate position of the scattering parameter; and generating the alignment operation instruction of the three-dimensional position of the probe according to the real part value change of the scattering parameter, including generating the alignment operation instruction that the XYZ axes positions of the three GSG contact points relative to the three contact pads are controlled so that the three GSG contact points are in contact with the three contact pads respectively according to the real part value change of the scattering parameter;

[0033] The probe GSG rotation angle fine adjustment system is used for receiving and executing the leveling operation instruction.

[0034] The probe three-dimensional position control system is used for receiving and executing the alignment operation instruction;

[0035] The wafer chuck is used for fixing the wafer electrode contact pad.

[0036] Preferably, the microscope is further used for displaying the observation position of the probe relative to the wafer electrode contact pad; in the leveling operation step of the probe according to the amplitude variation of the scattering parameter, the observation position is combined to adjust the probe to an initial position, the initial position is that the GSG three contacts are located in the positive direction of the Z axis of the electrode contact pad and in the XOY plane, the corresponding position range relative to the three contact pads; the included angle θ is regulated based on the initial position.

[0037] Preferably, the microscope is further used for displaying the observation position of the probe relative to the wafer electrode contact pad; in the three-dimensional position alignment operation step of the probe according to the real part value variation of the scattering parameter, the observation position is combined to adjust the probe to an initial height, the initial height is that the vertical distance between the probe and the wafer electrode contact pad is a fixed distance value; the positions of the GSG three contacts relative to the XYZ axes of the three contact pads are regulated based on the initial height.

[0038] According to the technical solutions, compared with the prior art, the present application has the following beneficial effects:

[0039] The present application can precisely adjust the positions of the probe in the X, Y and Z directions, and optimize the parallelism between the probe GSG contact and the wafer chip surface, thereby significantly enhancing the accuracy of the test results.

[0040] The present application combines optical positioning and electrical regulation technology to ensure the accuracy of the probe position and the high repeatability of the operation, which has significant significance for improving the yield of the chip and reducing the manufacturing cost.

[0041] The present application provides an innovative solution for the field of semiconductor chip testing to realize the precise control of the probe position on the wafer. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only belong to the embodiments of the present application, and those skilled in the art can obtain other drawings according to the provided drawings without any creative labor;

[0043] Figure 1A flow chart of a full-automatic control method of a radio frequency probe based on scattering parameter change is provided for an embodiment of the present application.

[0044] Figure 2 A schematic diagram of different contact states of a probe and a contact is provided for an embodiment of the present application.

[0045] Figure 3 A typical polar coordinate diagram of corresponding scattering parameters in different contact states is provided for an embodiment of the present application.

[0046] Figure 4 A graph of variation of a real part value of a scattering parameter S11 in a process of approaching a chip surface of a probe is provided for an embodiment of the present application.

[0047] Fig. 5(a) is a YOZ plane schematic diagram of a three-dimensional position alignment operation of a probe provided for an embodiment of the present application.

[0048] Fig. 5(b) is an XOY plane schematic diagram of a three-dimensional position alignment operation of a probe provided for an embodiment of the present application.

[0049] Figure 6 A schematic diagram of an execution specific step of a full-automatic control method of a radio frequency probe is provided for an embodiment of the present application.

[0050] Figure 7 A system architecture diagram of a full-automatic control system of a radio frequency probe is provided for an embodiment of the present application. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0052] As shown in the drawings, Figure 1 A first aspect of an embodiment of the present application provides a full-automatic control method of a radio frequency probe based on scattering parameter change. Three contacts of a probe GSG are used to simultaneously contact three contact pads of a wafer electrode contact plate to realize wafer testing. The method comprises the following steps:

[0053] In a process of moving and aligning the probe relative to the wafer electrode contact plate, scattering parameters of the three contacts GSG relative to the three contact pads are acquired in real time.

[0054] A leveling operation of the probe is performed according to a polar coordinate diagram position of the scattering parameters, comprising: adjusting an included angle θ between a line connecting the three contacts GSG and a plane where the electrode contact plate is located, so that the line connecting the three contacts GSG is parallel to the plane where the electrode contact plate is located.

[0055] According to the real part value change of the scattering parameter, the alignment operation of the three-dimensional position of the probe is performed, including: adjusting the position of the GSG three contacts relative to the XYZ axis of the three contact pads according to the real part value change of the scattering parameter, so that the GSG three contacts are respectively in contact with the three contact pads.

[0056] The principle of the leveling operation in the embodiment is described:

[0057] There are mainly three typical cases when the probe GSG three contacts are in contact with the chip, as shown in the figure: Figure 2 When the included angle θ between the straight line where the GSG three contacts of the probe are located and the contact surface of the chip is large, only one G contact point is in contact with the chip; when θ is small, there may be one G and one S two contact points in contact with the chip, and the other G contact point is suspended in the air; when θ is 0, two G and one S three contact points are all in contact with the chip, and the probe realizes leveling.

[0058] In order to distinguish the above three contact cases, a short-circuit contact plate can be selected to simulate the wafer chip, and the contact between the probe and the chip can be equivalent to the contact between the probe and the short-circuit contact plate. The equivalent circuit diagram of one G contact point in contact with the chip is two capacitors in parallel; the equivalent circuit diagram of one G and one S two contact points in contact with the chip is one capacitor and one inductor in parallel; and the equivalent circuit diagram of two G and one S three contact points all in contact with the chip is two inductors in parallel. As shown in the figure: Figure 3 Under different contact conditions, the typical polar coordinate diagram of the corresponding scattering parameter (the horizontal coordinate is the real part, and the vertical coordinate is the imaginary part) obtained from the vector network analyzer VNA. The numbers in the figure represent the number of contact probe tips (G or S).

[0059] When the GSG three contacts of the probe are all in good contact with the electrodes of the short-circuit contact plate, two parallel loops are formed between each ground contact G and the signal contact S, so there should be an inductance between them, and the amplitude |S11| of the corresponding obtained scattering parameter is approximately 1, in the upper left part of the Smith chart;

[0060] When only one G contact point of the GSG three contacts of the probe is in good contact with the electrodes of the short-circuit contact plate, or none of the three contacts is in good contact with the electrodes of the short-circuit contact plate, no loop is formed between each ground contact G and the signal contact S, and there should be an equivalent capacitor between the G contact point and the S contact point, and the amplitude |S11| of the corresponding obtained scattering parameter is approximately 1, in the lower right part of the Smith chart;

[0061] When the GSG three contacts of the probe only have one S contact and one G contact and are in good contact with the short-circuit contact plate electrode, a loop is formed between the contact G and the signal contact S, corresponding to the existence of an equivalent inductance, while another contact G and the signal contact S do not form a loop, corresponding to the existence of an equivalent capacitance. The inductance and the capacitance are connected in parallel to produce resonance in a wide frequency band range, corresponding to the obtained scattering parameter amplitude |S11| being mostly less than 1, in the internal region of the Smith chart.

[0062] Therefore, based on the characteristics of the S11 parameter, the actual contact number and the contact degree of the three contacts can be judged by analyzing the change rule of the S11 parameter when the GSG three contacts of the probe tip are in contact with the contact plate.

[0063] The principle of the alignment operation in the embodiment is described:

[0064] When the measured scattering parameter suddenly changes, it indicates that the probe is in contact with the chip. Therefore, the fine control in the Z-axis direction can be regulated by observing the scattering parameter. As shown in FIG. 6, an Infinity probe is gradually approached to an ISS Figure 4

[0065] 101-190C calibration process, the abscissa represents the total number of points recorded during the movement of the probe, and the ordinate represents the real part value of the scattering parameter S11 corresponding to each recording point.

[0066] It can be observed that when the probe is far away from the chip, the obtained S11 signal is almost constant; when the probe tip approaches the chip surface, it can be seen that the S11 signal begins to strengthen; and when the probe tip contacts the chip surface, the S11 signal suddenly increases sharply to a very high value. After this node, the probe is fine-tuned in the Z-axis direction to ensure that the probe tip and the chip are in good contact. When the probe moves away from the chip surface and gradually recovers, the behavior opposite to the process of the probe tip approaching the chip surface can be observed. Therefore, the relationship between the S11 signal mutation process when the probe tip contacts and moves away from the chip surface and the distance traveled by the probe tip in the Z-axis direction can provide a basis for establishing a probe position automatic regulation mechanism using real-time feedback of the VNA.

[0067] In one embodiment, the leveling operation of the probe is performed according to the amplitude change of the scattering parameter, including: judging whether the amplitude of the scattering parameter is 1 and located in the second quadrant of the polar coordinate diagram in real time, and if so, the line connecting the GSG three contacts is parallel to the plane where the wafer electrode contact plate is located, and the leveling operation is ended.

[0068] ​In one embodiment, the alignment operation of the three-dimensional position of the probe is performed according to the real part value change of the scattering parameter, including: judging whether the real part value of the scattering parameter appears an abrupt increase signal in real time, the change amplitude of the abrupt increase signal is greater than a preset value, if yes, the GSG three contacts are in contact with the three contact pads respectively, and the alignment operation of the three-dimensional position is ended.

[0069] In one embodiment, the coordinate system is regulated as follows: the Z axis is perpendicular to the direction of the electrode contact plate, and the XOY plane is parallel to the plane where the electrode contact plate is located; the leveling operation of the probe is performed according to the amplitude change of the scattering parameter, including:

[0070] S11: adjusting the probe to an initial position, the initial position is that the GSG three contacts are located in the positive direction of the Z axis of the electrode contact plate, and in the XOY plane, the corresponding position range of the three contact pads;

[0071] S12: controlling the probe to move step by step along the Z axis according to a preset step distance, and recording the amplitude of the scattering parameter in real time, if the amplitude of the scattering parameter is 1 and located in the second quadrant of the polar coordinate diagram, it is recorded as a first state, and S13 is entered; if the amplitude of the scattering parameter is less than 1, it is recorded as a second state, and S14 is entered; if the amplitude of the scattering parameter is 1 and located in the fourth quadrant of the polar coordinate diagram, it is recorded as a third state, and S15 is entered;

[0072] S13: tilting the probe according to a preset step angle until the scattering parameter enters the second state, recording the angle of the included angle θ, and recording it as A1; tilting the probe in the opposite direction according to a preset step angle until the scattering parameter enters the second state again, recording the angle of the included angle θ, and recording it as A2, and entering S16;

[0073] S14: determining the side where the contact pad not contacted by the contact is located, tilting the probe along the side direction according to a preset step angle until the scattering parameter enters the first state, recording the angle of the included angle θ, and recording it as A1; continuing to tilt the probe according to a preset step angle until the scattering parameter enters the second state again, recording the angle of the included angle θ, and recording it as A2, and entering S16;

[0074] S15: determining the number of contacts not contacting the contact pad, if it is 0, returning to S12; if it is 1, returning to S14;

[0075] S16: setting a target angle as the average value between A1 and A2, and regulating the included angle θ between the line connecting the GSG three contacts and the plane where the electrode contact plate is located to the target angle, and completing the leveling operation.

[0076] The operation process of the leveling probe is as follows: first, manually adjust the position of the suction cup so that the three contacts of the probe tip GSG are directly above the short-circuit calibration piece. Then, adjust the probe holder to move the probe downward along the Z-axis direction step by step, and the step distance can be set to 1 um. After each step, record the reflection parameter at the same time, and detect whether the three contacts of the probe tip are in contact with the ground by observing the sharp change of the parameter. After determining that the probe is in contact with the short-circuit calibration piece, continue to adjust the probe holder to move the probe downward along the Z-axis direction by a certain distance, such as 5 um, so that the probe tip is in good contact with the short-circuit calibration piece. Determine the contact between the probe and the calibration piece by observing the scattering parameter.

[0077] When the three contacts of the probe GSG are in contact with the calibration piece, adjust the probe by a fixed distance, such as 5 um, in the Z-axis direction, and set the initial angle at this time. Adjust the probe holder so that the probe is tilted by a certain step. When the number of contacts of the probe tip changes from three to two, record the angle of the probe tilt, denoted as A1. Next, adjust the probe holder to adjust the tilt angle of the probe to the initial angle, and tilt in the opposite direction by a certain step. When the number of contacts of the probe tip changes from three to two, record the angle of the probe tilt, denoted as A2.

[0078] When the probe has only two contacts with the calibration piece, determine which side of the probe tip is not in contact by microscope, and adjust the probe holder to tilt the probe tip to the side of the probe that is not in contact by a certain step. When the number of detected contact probe tips changes from two to three, record the angle of the probe tilt at this point, denoted as A1. Next, adjust the probe holder to continue tilting the probe in the same direction until the number of detected contact probe tips changes from three to two again, and record the angle of the probe tilt at this point, denoted as A2.

[0079] After determining the angles A1 and A2, adjust the probe holder to adjust the probe by a fixed distance in the Z-axis direction to release the probe, so that the probe tip is away from the surface of the calibration piece, to avoid damaging the probe tip during subsequent adjustment of the probe angle. Then, adjust the probe holder to set the tilt angle of the probe to the average value of A1 and A2, (A1+A2) / 2. After adjustment, the plane on which the probe GSG is located is parallel to the surface of the calibration chip.

[0080] In one embodiment, the alignment operation of the initial position in S11 is performed according to the real part value change of the scattering parameter.

[0081] In one embodiment, the coordinate system is adjusted as follows: the Z-axis is perpendicular to the direction of the electrode contact plate, the XOY plane is parallel to the plane on which the electrode contact plate is located, the X-axis is the arrangement direction of the three contact pads, and the Y-axis is the extension direction of the three contact pads on the wafer electrode contact plate. The alignment operation of the three-dimensional position of the probe is performed according to the real part value change of the scattering parameter, including:

[0082] adjusting the probe to an initial height, the initial height being the vertical distance between the probe and the wafer electrode pads being a fixed distance value;

[0083] controlling the probe to move step by step along the Y axis at the initial height according to a preset step distance, moving the probe downward along the Z axis by a fixed distance value after each step is completed, so that the contact points are in contact with the wafer electrode pads, recording the scattering parameters, until the real part value of the scattering parameters appears a sharp increase signal;

[0084] controlling the probe to move step by step along the X axis at the initial height according to a preset step distance, moving the probe downward along the Z axis by a fixed distance value after each step is completed, so that the contact points are in contact with the wafer electrode pads, recording the scattering parameters, until the real part value of the scattering parameters appears a sharp increase signal.

[0085] The sequence of the adjustment of the X axis and the Y axis in this embodiment is not distinguished. As an example, the adjustment sequence in the coordinate axis direction is Z direction, Y direction and X direction based on the probe leveling is used to describe this embodiment.

[0086] S21: First, the parameter of the probe tip in the Z direction is determined. The adjustment process can be ensured that the probe tip GSG three contact points are approximately aligned above the three contact pads of the electrode pads by the experience of the operator and the observation of the high-power microscope, but the probe is not in contact with the electrode pads. Then the operator fine adjusts the probe position by the method of this embodiment, as shown in FIG. 5(a), the probe tip is adjusted in the Z axis direction to slowly descend, the step distance is temporarily set to 1 um, and the scattering parameters are recorded after each step is completed. The probe has been in contact with the electrode pads by observing the parameter change, and the position parameter of the probe in the Z axis direction is confirmed.

[0087] S22: Adjust the probe 5 um in the Z axis direction to release the probe, so that the probe tip is away from the electrode pads. Adjust the probe holder to move the probe in the reverse direction along the Y axis about 1.5 times the wp distance (set wp as the side length of the square contact points of the calibration piece electrode), to ensure that it is away from the electrode pads. Continue to adjust the probe holder to move the probe step by step in the positive direction along the Y axis, the step distance is temporarily set to 1 um, and the probe is moved downward in the Z axis direction by 5 um after each step is completed, that is, the probe is pressed to make the probe tip in contact with the chip where the electrode pads are located, the scattering parameters are recorded, and the probe is lifted to continue the step. Repeat the above steps several times, when the scattering parameters are observed to change sharply, it indicates that the probe tip has contacted the left edge of the three electrode contact points, and the position parameter of the probe in the Y axis direction is confirmed.

[0088] S23: After detecting the left edge of the electrode contact pad in the Y-axis, the probe is adjusted 5 um in the Z-axis direction to release the probe and move the probe tip away from the electrode contact pad. Then, the probe holder is adjusted to move the probe in the X-axis direction by about 1.5 times the wp distance in the reverse direction to move the probe tip above the electrode contact pad in the X-axis direction. Then, the probe holder is adjusted to move the probe in the X-axis direction by 1 um in the positive direction, and after each step, the probe is moved 5 um in the Z-axis direction to press the probe, so that the probe tip contacts the chip where the electrode contact pad is located, and the scattering parameters are recorded. The probe is lifted and the step is repeated. Similarly, the probe is adjusted in the Y-axis direction, and the above steps are repeated several times to determine the position parameters in the X-axis direction.

[0089] S24: The GSG three contacts of the probe tip are at the edges of the electrode contact point in the Y-axis direction and at the edges of the electrode contact point in the X-axis direction, i.e., at the right-angled vertices of the XOY plane. After determining the coordinates of the point, since the size of the electrode contact pad is known, the probe is moved 0.5 wp in the X-axis direction and the Y-axis direction, respectively, to the center of the electrode contact pad, i.e., to the ideal target position of the probe adjustment.

[0090] As shown in Figure 6 , based on the above method, the repeatability of the probe coordinates and the pressing force can be achieved, and based on the electrode contact pad, all elements on the wafer where the electrode contact pad is located can be measured and analyzed with high precision.

[0091] In one embodiment, the scattering parameters of the GSG three contacts relative to the three contact pads are obtained in real time by using a vector network analyzer; after the calibration and adjustment module ensures the accuracy of the probe position and inclination, high-precision calibration of the vector network analyzer is performed. Therefore, the calibration steps of the vector network analyzer are also included:

[0092] The measured S parameters of the to-be-measured element are measured by using a calibration device;

[0093] The S parameters of the equivalent model of the to-be-measured element in the vector network analyzer are calculated;

[0094] The residual error between the measured S parameters and the equivalent model S parameters is minimized by using a nonlinear least squares algorithm.

[0095] In the specific implementation of the embodiment, the complex permittivity of the reference material is calculated by a computer and MATLAB software, and in the measurement stage, the S parameters of the straight-through piece, the short-circuit piece, the open-circuit piece and the transmission line are measured by using the calibration device, and the measurement data are transmitted to the computer for further data processing. The data processing steps include inputting the basic information of the calibration device, reading the S parameter file of the vector network analyzer, and calculating the S parameters of the equivalent model. Finally, by using the nonlinear least square algorithm, the residual error between the measured S parameters and the S parameters of the equivalent model is minimized, so as to extract the error term of the vector network analyzer, and the whole calibration process is completed. By using the accurate calibration method, it can be ensured that the vector network analyzer can perform high-precision measurement in a wide frequency range of 100 MHz to 100 GHz, and a reliable basis is provided for accurate analysis and measurement of high-frequency devices and systems.

[0096] The second aspect of the embodiment also provides a radio frequency probe full-automatic regulation and control system according to the first aspect of the embodiment, comprising: a probe, a vector network analyzer, a regulation and control module, a probe GSG rotation angle fine adjustment system, a probe three-dimensional position control system and a wafer chuck; wherein,

[0097] The vector network analyzer is connected with the probe, and is used for acquiring the scattering parameters of the three contact pads of the GSG three contact points relative to the three contact pads in real time in the process of moving and aligning the probe relative to the wafer electrode touch plate;

[0098] The regulation and control module is connected with the vector network analyzer, and is used for generating a leveling operation instruction of the probe according to the polar coordinate position of the scattering parameters, comprising: generating a leveling operation instruction of regulating the included angle θ between the GSG three contact point connecting line and the plane of the electrode touch plate, so that the GSG three contact point connecting line is parallel to the plane of the electrode touch plate according to the polar coordinate position of the scattering parameters; and generating an alignment operation instruction of the three-dimensional position of the probe according to the real part value change of the scattering parameters, comprising: generating an alignment operation instruction of regulating the XYZ axis position of the GSG three contact points relative to the three contact pads according to the real part value change of the scattering parameters, so that the GSG three contact points are in contact with the three contact pads respectively;

[0099] The probe GSG rotation angle fine adjustment system is used for receiving and executing the leveling operation instruction;

[0100] The probe three-dimensional position control system is used for receiving and executing the alignment operation instruction;

[0101] The wafer chuck is used for fixing the wafer electrode touch plate.

[0102] In one embodiment, the microscope is further included for displaying an observation position of the probe relative to the wafer electrode pad; in the step of performing the leveling operation of the probe according to the amplitude variation of the scattering parameter, the probe is adjusted to an initial position in combination with the observation position, the initial position being that the three GSG contacts are located in the positive direction of the Z axis of the electrode pad and in the corresponding position range relative to the three contact pads in the XOY plane; and the angle θ is regulated based on the initial position.

[0103] In one embodiment, the microscope is further included for displaying an observation position of the probe relative to the wafer electrode pad; in the step of performing the three-dimensional position alignment operation of the probe according to the real part value variation of the scattering parameter, the probe is adjusted to an initial height in combination with the observation position, the initial height being that the vertical distance between the probe and the wafer electrode pad is a fixed distance value; and the positions of the three GSG contacts relative to the XYZ axes of the three contact pads are regulated based on the initial height.

[0104] In one embodiment, as shown in Figure 7 The probe station system is built for mounting the probe XYZθ positioning device 4, the wafer chuck 5, and the microscope. The probe XYZθ positioning device 4 includes the probe GSG rotation angle fine-tuning system and the probe three-dimensional position control system, and the probe station system can adopt the air-floating probe station. The high-stability microscope bridge is mounted on the probe station system to mount the high-power microscope. The 100MHz-100GHz vector network analyzer, the high-frequency 100um GSG probe, and the adjustable 6-inch wafer chuck are used.

[0105] The air-floating probe station and the high-stability microscope bridge provide a stable and accurate observation and operation platform for the system. Through the cooperation of the vector network analyzer and the high-power microscope, the contact points between the probe and the wafer can be accurately observed and analyzed. The high-frequency GSG probe as the key component for contacting the wafer, the accurate control of its position is completed by the probe three-dimensional position control system and the probe GSG rotation angle fine-tuning system. In addition, the adjustable 6-inch wafer chuck provides a stable fixing and adjusting platform for the wafer, and the calibration and adjustment chip is used for system calibration to ensure the accuracy of the probe position and the inclination angle.

[0106] In this embodiment, the full-automatic radio frequency probe regulation and control system is calibrated by the coaxial calibration and the SOL calibration, and is used to perform the full-automatic radio frequency probe regulation and control method provided in the first aspect of the embodiment.

[0107] In one embodiment, the probe three-dimensional position control and GSG rotation angle fine-tuning system adopts the stick-slip driving technology of SmarAct. Since the SmarAct stick-slip driving piezoelectric displacement table is equipped with a specific driver, it can realize the efficient combination of macro travel and nanometer resolution. The precise adjustment of the probe rotation angle adopts the SR series module of SmarAct, such as the precise ceramic SR-2013 module, whose angular resolution reaches 25 μ°. The precise adjustment in the X, Y and Z axis directions adopts the SLC series module of SmarAct based on cross-roller bearing linear sliders. For example, the SLC1730 piezoelectric regulation platform with a size of 30 x 17 x 8.5 mm, a travel range of 21 mm and a normal load of 20 N, and the SLC2430 piezoelectric regulation platform with a size of 30 x 24 x 10.5 mm, a travel range of 16 mm and a normal force of 30 N. The closed-loop resolution MCS2 of both reaches 1 (S) nm and 4 (L) nm. This system significantly reduces the need for manual intervention and the use of microscopes by integrating stick-slip driving technology and a microcomputer control system, thereby improving the automation level of the test process.

[0108] The above describes in detail the radio frequency probe full-automatic regulation and control method and system based on scattering parameter change provided by the present application. The principle and implementation manner of the present application are described by applying specific examples in the embodiment. The above embodiment description is only used to help understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the field, according to the idea of the present application, the specific implementation manner and application range will be changed, and the above description of the present application should not be understood as a limitation.

[0109] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined in the present embodiment can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown in the present embodiment, but will conform to the widest scope consistent with the principles and novel features disclosed in the present embodiment.

Claims

1. A full-automatic control method of a radio frequency probe based on scattering parameter variation, characterized in that, The three contacts of the probe GSG are used to simultaneously contact three contact pads of a wafer electrode touch plate to realize wafer testing; the method comprises the following steps: In the process of aligning the probe relative to the wafer electrode touch plate, the scattering parameters of the three contacts of the probe GSG relative to the three contact pads are acquired in real time; According to the position of the polar coordinate diagram of the scattering parameters, the leveling operation of the probe is performed, comprising: adjusting the angle θ between the line connecting the three contacts of the probe GSG and the plane of the wafer electrode touch plate according to the position of the polar coordinate diagram of the scattering parameters, so that the line connecting the three contacts of the probe GSG is parallel to the plane of the wafer electrode touch plate; According to the change of the real part value of the scattering parameters, the alignment operation of the three-dimensional position of the probe is performed, comprising: adjusting the position of the three contacts of the probe GSG relative to the XYZ axes of the three contact pads according to the change of the real part value of the scattering parameters, so that the three contacts of the probe GSG are respectively in contact with the three contact pads.

2. The full-automatic control method of radio frequency probe based on scattering parameter variation according to claim 1, characterized in that, According to the change of the amplitude of the scattering parameters, the leveling operation of the probe is performed, comprising: judging in real time whether the amplitude of the scattering parameters is 1 and located in the second quadrant of the polar coordinate diagram, if yes, the line connecting the three contacts of the probe GSG is parallel to the plane of the wafer electrode touch plate, and the leveling operation is ended.

3. The full-automatic control method of radio frequency probe based on scattering parameter variation according to claim 1, characterized in that, According to the change of the amplitude of the scattering parameters, the leveling operation of the probe is performed, comprising:

4. The full-automatic control method of radio frequency probe based on scattering parameter variation according to claim 1, characterized in that, The coordinate system is adjusted, wherein the Z axis is perpendicular to the direction of the electrode touch plate, and the XOY plane is parallel to the plane of the electrode touch plate; according to the change of the amplitude of the scattering parameters, the leveling operation of the probe is performed, comprising: S11: adjusting the probe to an initial position, wherein the initial position is that the three contacts of the probe GSG are located in the positive direction of the Z axis of the electrode touch plate, and in the XOY plane, the corresponding positions of the three contacts of the probe GSG are located in the corresponding position range of the three contact pads; S12: controlling the probe to move step by step downward along the Z axis according to a preset step distance, recording the amplitude of the scattering parameters in real time, if the amplitude of the scattering parameters is 1 and located in the second quadrant of the polar coordinate diagram, recording as a first state, entering S13; if the amplitude of the scattering parameters is less than 1, recording as a second state, entering S14; if the amplitude of the scattering parameters is 1 and located in the fourth quadrant of the polar coordinate diagram, recording as a third state, entering S15; S13: tilting the probe according to a preset step angle until the scattering parameters enter the second state, recording the angle of the angle θ as A1; tilting the probe in the reverse direction according to a preset step angle until the scattering parameters enter the second state again, recording the angle of the angle θ as A2, entering S16; S14: determining the side where the contact of the probe GSG is not in contact with the contact pad, tilting the probe along the side according to a preset step angle until the scattering parameters enter the first state, recording the angle of the angle θ as A1; continuing to tilt the probe according to a preset step angle until the scattering parameters enter the second state again, recording the angle of the angle θ as A2, entering S16; S15: tilting the probe according to a preset step angle until the scattering parameters enter the second state, recording the angle of the angle θ as A1; tilting the probe in the reverse direction according to a preset step angle until the scattering parameters enter the second state again, recording the angle of the angle θ as A2, entering S16. S15: determine the number of contacts not contacting the contact pads, if 0, return to S12; if 1, return to S14; S16: set the target angle as the average value between A1 and A2, and control the angle θ between the three contact points of GSG and the plane of the wafer electrode touch plate to the target angle, complete the leveling operation.

5. The full-automatic control method of radio frequency probe based on scattering parameter variation according to claim 4, characterized in that, According to the real part value change of the scattering parameter, the alignment operation of the initial position in S11 is performed.

6. The full-automatic control method of radio frequency probe based on scattering parameter variation according to claim 1, characterized in that, The coordinate system is adjusted as follows: the Z axis is perpendicular to the direction of the electrode touch plate, the XOY plane is parallel to the plane of the electrode touch plate, the X axis is the arrangement direction of the three contact pads, and the Y axis is the extension direction of the three contact pads on the wafer electrode touch plate; according to the real part value change of the scattering parameter, the alignment operation of the three-dimensional position of the probe is performed, including: Adjusting the probe to an initial height, the initial height being the vertical distance between the probe and the wafer electrode touch plate being a fixed distance value; According to a preset step distance, controlling the probe to move step by step along the Y axis at the initial height, after each step is completed, controlling the probe to move downward along the Z axis by the fixed distance value, so that the contact point contacts the wafer electrode touch plate, and recording the scattering parameter until the real part value of the scattering parameter appears a sharp increase signal; According to a preset step distance, controlling the probe to move step by step along the X axis at the initial height, after each step is completed, controlling the probe to move downward along the Z axis by the fixed distance value, so that the contact point contacts the wafer electrode touch plate, and recording the scattering parameter until the real part value of the scattering parameter appears a sharp increase signal.

7. The full-automatic control method of radio frequency probe based on scattering parameter variation according to claim 1, characterized in that, The scattering parameter of the three contact points of GSG relative to the three contact pads is obtained in real time by using a vector network analyzer; further including a calibration step of the vector network analyzer: Measuring the measured S parameter of the to-be-tested member by using a calibration device; Calculating the S parameter of the equivalent model of the to-be-tested member in the vector network analyzer; By a nonlinear least square algorithm, minimizing the residual error between the measured S parameter and the equivalent model S parameter.

8. A radio frequency probe automatic control system based on the automatic control method of radio frequency probe according to any one of claims 1-7, characterized in that, Including: The probe, the vector network analyzer, the control module, the probe GSG rotation angle fine adjustment system, the probe three-dimensional position control system and the wafer chuck; wherein, The vector network analyzer is connected with the probe, and is used to obtain the scattering parameter of the three contact points of GSG relative to the three contact pads in real time during the movement alignment of the probe relative to the wafer electrode touch plate; The control module is connected with the vector network analyzer, and is used to generate the leveling operation instruction of the probe according to the polar coordinate position of the scattering parameter, including: generating the leveling operation instruction of controlling the angle θ between the three contact points of GSG and the plane of the wafer electrode touch plate to make the three contact points of GSG parallel to the plane of the wafer electrode touch plate according to the polar coordinate position of the scattering parameter; and generating the alignment operation instruction of the three-dimensional position of the probe according to the real part value change of the scattering parameter, including: generating the alignment operation instruction of controlling the XYZ axis position of the three contact points of GSG relative to the three contact pads to make the three contact points of GSG contact the three contact pads respectively according to the real part value change of the scattering parameter; The probe GSG rotation angle fine-tuning system is configured to receive and execute the leveling operation instruction; The probe three-dimensional position control system is configured to receive and execute the alignment operation instruction; The wafer chuck is configured to fix the wafer electrode contact pad.

9. The full-automatic regulating system of radio frequency probe according to claim 8, characterized in that, Further comprising a microscope; the microscope is configured to display the observation position of the probe relative to the wafer electrode contact pad; in the leveling operation step of the probe according to the amplitude change of the scattering parameter, the probe is adjusted to an initial position in combination with the observation position, the initial position is that the three contact points of the GSG are located in the positive direction of the Z axis of the electrode contact pad, and in the XOY plane, the corresponding position range relative to the three contact pads; the included angle θ is adjusted based on the initial position.

10. The full-automatic regulating system of radio frequency probe according to claim 8, characterized in that, Further comprising a microscope; the microscope is configured to display the observation position of the probe relative to the wafer electrode contact pad; in the alignment operation step of the three-dimensional position of the probe according to the real part value change of the scattering parameter, the probe is adjusted to an initial height in combination with the observation position, the initial height is that the vertical distance between the probe and the wafer electrode contact pad is a fixed distance value; the positions of the three contact points of the GSG relative to the XYZ axes of the three contact pads are adjusted based on the initial height.

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