A needle alignment method for an electrical characteristic detection device with multi-directional contact points

Abstract

The present application relates to the technical field of electrical characteristic detection, and particularly relates to a needle alignment method of an electrical characteristic detection device with multi-directional contact points, which technical scheme comprises the following steps: in the state that a plurality of needles are inserted into and installed in the through holes respectively formed by an upper guide plate and a lower guide plate, taking the guide plate plane as a reference, simultaneously moving any one of the upper guide plate and the lower guide plate along the X-axis and Y-axis directions, so that the plurality of needles inserted into the through holes are simultaneously aligned in the same direction; by moving the guide plate along the X-axis and Y-axis directions, the effect that the needles located in the through holes are aligned in the required direction according to different directions can be achieved, and not only the needles can be uniformly aligned in the required direction, but also the needle distortion caused by the guide plate pressure can be maximally reduced.

Description

Technical Field

[0001] This invention relates to the field of electrical characteristic testing technology, and in particular to a method for aligning an electrical characteristic testing device with multi-directional contact points. Background Technology

[0002] Typically, after semiconductors or semiconductor packaged circuit boards are manufactured, an inspection process is performed. Specifically, an electrical signal is applied to the object being tested, and the resulting detection signal is used to determine whether the object has defects. This inspection process utilizes inspection equipment to check the chips or circuit boards on the wafer.

[0003] These electrical characteristic testing devices have the following structural function: by contacting the needles of the needle module with electrodes on various parts of the wafer or circuit patterns and contacts on the circuit board, and then conducting a specific current through the needles, the electrical characteristics output at this time are measured. The needle module includes multiple needles for contacting the object being tested and applying electrical signals. For example... Figure 1 As shown, the needle module includes an upper guide plate 10 and a lower guide plate 20 spaced apart in the vertical direction. The upper guide plate 10 has multiple No. 1 through holes 11, and the lower guide plate 20 has multiple No. 2 through holes 21. A needle 40 is inserted into the No. 1 through holes 11 and the No. 2 through holes 21 and formed as a support on one side of the inner surface of the upper guide plate 10 and the lower guide plate 20.

[0004] In this traditional electrical characteristic testing device, when the object being tested moves upward, the lower end of the needle 40 contacts the object being tested G, and a specific current is passed through the needle 40 to the object being tested G. Then, the electrical signal output from the object being tested G is sent to an external testing device to confirm whether there is a problem with the object being tested G.

[0005] However, if the needle 40 of the electrical characteristic testing device cannot be precisely aligned with the contact area of ​​the object being tested G, it will lead to unstable contact between the two. This instability will not only cause incomplete signal transmission and result in testing errors, but will also cause wear or damage to the needle during repeated testing, thereby shortening the service life of the equipment.

[0006] Therefore, during the manufacturing process of the electrical characteristic testing device, it is necessary to align the positions of the pins 40. A conventional method, as shown in published patent KR20040105785A, involves using an independent alignment device to align the pins individually while they are inserted into a guide plate.

[0007] However, aligning the needles one by one is time-consuming, resulting in a significant reduction in production efficiency.

[0008] To address this issue, the applicant attempted to insert multiple pins into a guide plate and apply pressure to one side of the pins supported on the inner surface of the guide plate by unidirectionally moving either the upper or lower guide plate, while simultaneously aligning the pins as a whole. However, as semiconductor design rules continue to shrink, modern semiconductor devices exhibit a parallel trend towards high integration and miniaturization. To meet the increasingly miniaturized semiconductor device patterns, the pins must also be correspondingly reduced in size, and the spacing between the pins must be more compact to form a micro-pitch structure. This results in the pins being misaligned in multiple directions within the socket, and when attempting to align them by unidirectionally moving the guide plate, pins aligned perpendicular to the direction of movement will misalign with other pins in the Y-axis direction.

[0009] In view of this, we propose a method for solving the existing problems using an electrical characteristic testing device with multi-directional contact points. Summary of the Invention

[0010] The purpose of this invention is to provide a method for aligning an electrical characteristic testing device with multi-directional contact points, so as to solve the problems mentioned in the background art.

[0011] To achieve the above objectives, the present invention provides the following technical solution: a method for aligning an electrical characteristic testing device with multi-directional contact points, applied to an electrical characteristic testing device having multi-directional contact points with needles arranged in different directions according to the contact points of the test object within a through hole of a guide plate. With multiple needles inserted and installed within the through holes formed by the upper and lower guide plates respectively, using the plane of the guide plate as a reference, either the upper or lower guide plate is moved simultaneously along the X and Y axes, so that the multiple needles inserted into the through holes are simultaneously aligned in the same direction.

[0012] Furthermore, the through hole has a preset length along the moving direction of the guide plate, and the positioning of the needle is controlled by adjusting the pressure on the inner surface of the guide plate.

[0013] Furthermore, the needles are preheated before pressure is applied to minimize the bending difference between multiple needles while enhancing their strength.

[0014] Furthermore, let the value of the through hole diameter minus the needle diameter be value one, and let the lateral distance from the vertex of the curved part of the needle with the largest curvature among the multiple needles to the needle tip be value two. The movement range of the guide plate is controlled within the sum of value one and value two.

[0015] Furthermore, the guide plate moves in the following direction: the midpoint of the angle formed between the line connecting the needles from the zero point to the needles closest to the Y-axis+ region and the line connecting the zero point to the needles closest to the Y-axis- region, with the virtual Y-axis as the zero point on the through-hole plane as the reference.

[0016] Furthermore, at least one pair of alignment holes with a certain distance between them and having a unidirectional length are provided on one side of the upper guide plate or the lower guide plate. When a pair of alignment holes is defined as a group, multiple groups of alignment holes with different directional lengths are provided. Reference holes are provided on one side of the pad block between the upper guide plate and the lower guide plate, corresponding to the alignment holes. With the reference pins inserted into one group of alignment holes and their corresponding reference holes in the multiple groups of alignment holes, the upper guide plate is moved simultaneously along the X-axis and Y-axis directions according to the length direction of the alignment holes, with the plane as the reference.

[0017] Furthermore, the actual coordinate data of each needle tip in the needle module in three-dimensional space is obtained through a high-precision visual positioning unit; multi-dimensional micro-displacement is applied to the guide plate through a multi-axis linkage execution unit; the contact stress distribution of the needle body in the through hole of the guide plate is monitored in real time through a distributed stress sensing unit; the closed-loop control unit calculates the coordinated control command for each micro-actuator based on the deviation between the coordinate data collected by the high-precision visual positioning unit and the preset target coordinates, and in combination with the stress information fed back by the distributed stress sensing unit; the multi-axis linkage execution unit is driven to perform compound fine adjustment of the guide plate until the deviation between the actual coordinates and the target coordinates of all needle tips falls within the preset tolerance range, and the stress distribution uniformity monitored by the distributed stress sensing unit reaches the preset threshold.

[0018] Furthermore, the multi-axis linkage actuator includes at least three independently controlled micro-actuators.

[0019] Furthermore, the actuators are distributed asymmetrically around the upper and lower guide plates.

[0020] Furthermore, the distributed stress sensing unit is integrated at the contact interface between the guide plate and the needle body or at the force application end of the actuator.

[0021] Compared with the prior art, the beneficial effects of the present invention are: With multiple needles inserted and installed in the through holes formed by the upper and lower guide plates respectively, the present invention uses the plane of the guide plates as a reference and moves either the upper or lower guide plates simultaneously along the X and Y axes, so that the multiple needles inserted into the through holes are simultaneously aligned in the same direction. By moving the guide plates along the X and Y axes, the needles located in the through holes facing different directions can be aligned in the desired direction. Furthermore, not only can the needles be uniformly aligned to the desired direction, but the needle torsion deformation caused by the pressure of the guide plates can also be minimized. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a conventional electrical characteristic testing device; Figure 2This is a schematic diagram of an electrical characteristic detection device with multi-directional contact points based on an embodiment of the present invention; Figure 3 This is a first state diagram of an electrical characteristic detection device with multi-directional contact points based on an embodiment of the present invention, showing the alignment of a pin with a moving guide plate. Figure 4 This is a second schematic diagram showing the alignment of a needle with a multi-directional contact point using a moving guide plate, based on an embodiment of the present invention. Figure 5 This is a schematic diagram illustrating, conceptually, the state of setting the movement amount of the upper guide plate based on an embodiment of the present invention; Figure 6 This is a schematic diagram illustrating, conceptually, the state of the moving direction of the upper guide plate based on an embodiment of the present invention; Figure 7 This is a cross-sectional view of the reference pin insertion alignment hole and the reference hole state according to another embodiment of the present invention; Figure 8 This is a schematic diagram of the upper guide plate surface according to another embodiment of the present invention; Figure 9 This is an intelligent alignment system based on the last embodiment of the present invention, which involves multi-degree-of-freedom collaborative control.

[0023] In the diagram: 10, upper guide plate; 11, through hole No. 1; 12, alignment hole; 20, lower guide plate; 21, through hole No. 2; 30, pad; 31, reference hole; 40, needle; 41, needle tip; 42, needle tip; 43, main body; G, object to be tested; P, reference pin. Detailed Implementation

[0024] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Example 1

[0025] like Figure 1As shown, the conventional electrical characteristic testing device consists of an upper guide plate 10, a lower guide plate 20, a pad 30, and a needle 40. The upper guide plate 10 is a plate-like structure with a certain thickness, and one side is pre-set with multiple through holes 11 at fixed intervals. The guide plate supports the needle tip 41 of the needle 40 when the needle 40 is inserted into the through hole 11. The lower guide plate 20 is similar to the upper guide plate 10, also a plate-like structure with a certain thickness, and one side is pre-set with multiple through holes 21 at fixed intervals. It is located below the upper guide plate 10 and maintains a certain distance from the upper guide plate 10. When the needle tip 42 of the needle 40 is inserted into the through hole 21, one side of the inner surface of the lower guide plate 20 contacts the side of the needle tip 42 of the needle 40 and provides support. The pad 30 has a block-like structure and is positioned between the two ends of the upper guide plate 10 and the two ends of the lower guide plate 20. Its function is to maintain the distance between the upper guide plate 10 and the lower guide plate 20. The needle 40 has a vertically oriented rod-like structure and can be divided into a needle head 41 at the upper end, a needle tip 42 at the lower end, and a main body 43 in the middle. After the needle head 41 of the needle 40 is inserted into the first through hole 11, it forms a support on one side of the inner surface of the upper guide plate 10. After the needle tip 42 is inserted into the second insertion hole, it forms a support on one side of the inner surface of the lower guide plate 20. The needle 40 makes elastic contact with the prepared test object through its needle tip 42, and then a specific current is passed through it. At the same time, the electrical signal output at this time is transmitted to the external test equipment through the space converter connected to the upper part.

[0026] like Figure 2 As shown, multiple needles 40 are arranged on one side of the inner surface of the upper guide plate 10 with the No. 1 through hole 11 as a reference, thereby forming the optimal micro-pitch and ensuring accurate contact with the pre-set position of the object to be detected.

[0027] In an electrical characteristic testing device with this type of structure, the operation based on the needle 40 alignment method is as follows: First, during the manufacturing process of the electrical characteristic testing device, multiple pre-prepared pins 40 are inserted and installed into through holes 11 and 21. At this time, the multiple pins 40 are aligned in different directions in through hole 11 with the upper guide plate 10 as a reference, which not only forms a micro-pitch structure, but also ensures precise contact with the predetermined position of the object to be tested.

[0028] like Figure 3 and Figure 4As shown, by simultaneously moving the upper guide plate 10 along both the X and Y axes, multiple needles 40 can be subjected to pressure applied by the upper guide plate 10 in the direction of movement, thereby achieving synchronous alignment of multiple needles 40. Instead of simply moving the upper guide plate 10 linearly along either the X or Y axis, it moves it diagonally, thus achieving the effect of simultaneously aligning multiple needles 40. This design eliminates the need for additional alignment devices or alignment processes, enabling rapid alignment of multiple needles 40.

[0029] At this time, the amount and direction of movement of the upper guide plate 10 are set as follows.

[0030] First, the movement of the upper guide plate 10 is controlled within the following set range: such as Figure 5 As shown, d1 is the value obtained by subtracting the diameter of the needle 40 from the diameter of the first through hole 11 into which the needle 40 is inserted. The needle 40 with the greatest degree of curvature is selected from among the multiple needles 40, and a virtual vertical line is drawn at the apex of the curved portion of this needle 40. The distance d2 from this vertical line to the farthest end of the needle 40 is controlled within the range of the sum of these two values, d1 + d2. This is to ensure stable alignment of the needle 40 within the first through hole 11, while also taking into account differences in needle curvature caused by manufacturing errors, and minimizing the torsional deformation of the needle 40 caused by the pressure of the upper guide plate 10 moving.

[0031] Typically, the bending direction of the needle 40 is formed along the X-axis, and the multiple needles 40 are elastic relative to the X-axis. Therefore, when the upper guide plate 10 is moved, the amount of movement in the X-axis direction can be set within the range corresponding to the elastic force of the needle 40, so that the multiple needles 40 are simultaneously aligned with the desired Y-axis direction.

[0032] Then, the moving direction M of the upper guide plate 10 should be maintained in the following directions: such as Figure 6 As shown, taking the virtual Y-axis with the center point of each No. 1 through hole 11 in the plane as the zero point as the reference, when drawing the connecting line from the zero point to the center of the needle 40 inserted into the corresponding No. 1 through hole 11, among the multiple connecting lines formed by multiple No. 1 through holes and their corresponding multiple needles, the connecting line closest to the Y-axis+ region is the No. 1 connecting line L1; the connecting line closest to the Y-axis- region is the No. 2 connecting line L2. Based on this premise, the moving direction M of the upper guide plate 10 should be kept in the middle direction of the angle formed by the two connecting lines.

[0033] This is to take into account the positions of the two needles 40 with the largest positional deviation among the multiple needles 40, and move the upper guide plate 10 to the middle direction M between the two positions, thereby optimizing the alignment efficiency of the needles 40.

[0034] The needle 40 alignment method of the electrical characteristic detection device with multi-directional contact points is based on the above method. By setting the amount and direction of movement of the upper guide plate 10, the alignment operation of multiple needles 40 can be performed more efficiently.

[0035] The needle 40, which is aligned using the same method as in this embodiment, is preferably manufactured using MEMS technology and subjected to predetermined heating before pressure is applied, in order to minimize the bending of the manufactured needle 40 and enhance its strength, thereby minimizing the torsional deformation caused by the pressure applied to the guide plate. Example 2

[0036] Figure 7 and Figure 8 The needle alignment method involved is the same as Figures 1 to 5 The embodiments are the same, but a structure is provided that can complete the guide plate movement operation more quickly and accurately.

[0037] First, assume that the guide plate used to align the needle 40 is the upper guide plate 10, such as Figure 7 As shown, the difference between this embodiment and the previous embodiment is that: at least one pair of alignment holes 12 with a certain distance between them and a unidirectional length are provided on one side of the upper guide plate 10, and reference holes 31 are provided on one side of the pad block 30 corresponding to the alignment holes 12.

[0038] At this time, when a pair of alignment holes 12 are considered as a group, then the upper guide plate 10 is provided with the following... Figure 8 The diagram shows multiple sets of alignment holes 12 with different lengths in different directions.

[0039] Then, insert the reference pin P into one of the multiple sets of alignment holes 12 and its corresponding reference hole 31. After the reference pin P is inserted into the alignment hole 12, move the upper guide plate 10 simultaneously along the X-axis and Y-axis directions to align the needle 40.

[0040] In this embodiment, the alignment hole 12 guides the upper guide plate 10 to move in the direction and amount of movement, which ensures that the alignment operation of the needle 40 is completed quickly and with extremely high precision.

[0041] Furthermore, in this embodiment, the direction and amount of movement of the upper guide plate 10 will vary depending on the arrangement environment of the needles 40. That is to say, by selectively utilizing any set of alignment holes 12 that meet the environmental conditions, this device can flexibly cope with various environmental conditions or various arrangement states of the needles 40.

[0042] Apart from the above, the structure is the same as the basic embodiment described above, and other descriptions are omitted here. Example 3

[0043] To further improve the accuracy, consistency, and reliability of needle array alignment in high-density multi-directional contact point electrical characteristic testing devices, such as... Figure 9As shown, a high-precision visual positioning unit, a multi-axis linkage execution unit, a distributed stress sensing unit, and a closed-loop control unit are coupled together with a precise data link and a mechanical interface to form an intelligent alignment system capable of multi-degree-of-freedom coordinated control of a high-density needle array.

[0044] The high-precision visual positioning unit acquires the actual coordinate data of each needle tip in three-dimensional space; the multi-dimensional micro-displacement is applied to the guide plate by the multi-axis linkage execution unit, which includes at least three independently controlled micro-actuators distributed asymmetrically around the upper and lower guide plates; the contact stress distribution of the needle body within the through-hole of the guide plate is monitored in real time by the distributed stress sensing unit, which is integrated at the contact interface between the guide plate and the needle body or at the force application end of the actuator; the closed-loop control unit calculates the coordinated control command for each micro-actuator based on the deviation between the coordinate data acquired by the high-precision visual positioning unit and the preset target coordinates, and in combination with the stress information fed back by the distributed stress sensing unit; the multi-axis linkage execution unit is driven to perform compound fine-tuning of the guide plate until the deviation between the actual coordinates and the target coordinates of all needle tips falls within the preset tolerance range, and the stress distribution uniformity monitored by the distributed stress sensing unit reaches the preset threshold.

[0045] The high-precision visual positioning unit includes a confocal displacement sensor array and a high-speed area array image sensor. The confocal displacement sensor array is arranged in an oblique incidence manner to accurately measure the axial height of the needle tip relative to the plane of the object being detected. The high-speed area array image sensor acquires a top-view image of the needle array from directly above and extracts the planar coordinates of each needle tip through a sub-pixel edge positioning algorithm. The visual positioning unit spatially fuses the axial height data and the planar coordinate data to output the complete three-dimensional coordinates of each needle tip.

[0046] Each micro-actuator in the multi-axis linkage actuator adopts a configuration combining piezoelectric ceramic drive and flexible hinge transmission; the piezoelectric ceramic driver provides displacement output with nanometer-level resolution; the flexible hinge converts the linear output of the piezoelectric ceramic into a precise push-pull force on a specific point on the edge of the guide plate; the three actuators are optimized according to the density distribution of the needle array and the rigidity characteristics of the guide plate to ensure that the guide plate can be precisely controlled with a total of three degrees of freedom, including micro-rotation about two orthogonal axes in its plane and micro-translation along its normal.

[0047] The distributed stress sensing unit uses a microelectromechanical system thin-film pressure sensor array. The sensor array is embedded in the inner wall of the through hole of the guide plate. Each through hole has four independent sensitive elements evenly distributed circumferentially to detect the contact pressure between the needle and the inner wall of the through hole at different positions.

[0048] The distributed stress sensing unit integrates strain sensing elements directly into the output end of the micro-actuator; it inversely calculates the force exerted on the guide plate by measuring the micro-strain of the actuator output rod.

[0049] The core control logic of the closed-loop control unit includes a two-stage decoupled controller. The first stage is the position loop controller, whose input is the deviation vector of the three-dimensional coordinates of each needle tip. Through a preset coordinate-actuator displacement transfer function matrix, the theoretical displacement of each group of micro-actuators is initially calculated. The second stage is the stress loop controller, whose input is the stress distribution uniformity index fed back by the distributed stress sensing unit. This index is obtained by calculating the ratio of the standard deviation to the mean of the stress at all sensitive points. The stress loop controller corrects the theoretical displacement output of the first stage based on this index. The correction strategy is to prioritize adjusting the actuator displacement that plays a major regulatory role in the guide plate part corresponding to the high stress area when the stress distribution uniformity does not meet the standard.

[0050] The specific execution flow of the Qi method includes: system initialization, the high-precision visual positioning unit performs the first three-dimensional scan of the needle module to obtain the initial coordinate set of the needle tip; the closed-loop control unit calculates the spatial deviation between the initial coordinate set and the target coordinate set; the multi-axis linkage execution unit performs the first collaborative fine-tuning according to the instructions of the closed-loop control unit; after fine-tuning, the high-precision visual positioning unit immediately performs the second three-dimensional scan, and the distributed stress sensing unit synchronously records the stress data; the closed-loop control unit compares the coordinate changes and stress changes of the two scans, and optimizes the parameters of its internal coordinate-actuator displacement transfer function matrix accordingly; this process is iterated until the convergence condition that the coordinate deviation of all needle tips is less than 2 micrometers and the stress distribution uniformity index is less than 0.1 is met simultaneously.

[0051] The calculation process of the stress distribution uniformity index is as follows: read the stress data of all effective sensitive points from the distributed stress sensing unit to form a stress vector; calculate the arithmetic mean of the stress vector; calculate the sum of squares of the deviations of each stress value from the mean, divide by the number of data points minus 1, and take the square root to obtain the standard deviation; finally, the stress distribution uniformity index is equal to the standard deviation divided by the mean.

[0052] Before the alignment process begins, the system performs a pre-calibration of the guide plate flatness and the initial posture of the needle. The pre-calibration process uses a high-precision vision positioning unit to measure the reference plane of the guide plate under no external load and records the natural tilt angle of each needle in the through hole. These pre-calibration data serve as the basis for setting the initial parameters of the closed-loop control unit and are used to compensate for systematic deviations caused by machining tolerances.

[0053] The method also includes an adaptive learning module; the adaptive learning module records complete data of each alignment process, including initial deviation, control command sequence, final alignment accuracy and stress uniformity; by analyzing this historical data, the adaptive learning module can establish a mapping relationship between the dynamic response characteristics of the needle array under different wear conditions and temperature environments and the optimal control parameters, and provide predictive parameter presets for the closed-loop control unit in subsequent alignment processes.

[0054] The preferred embodiments of the present invention have been described in detail above, but various modifications or variations can be made without departing from the spirit and scope of the invention. Therefore, the appended claims cover all such modifications or variations that conform to the spirit of the present invention.

Claims

1. A method for aligning an electrical characteristic testing device with multi-directional contact points, applied to an electrical characteristic testing device having multi-directional contact points arranged in different directions according to the contact points of the object being tested, within a through hole of a guide plate, characterized in that: With multiple needles inserted and installed in the through holes formed by the upper and lower guide plates respectively, using the plane of the guide plate as a reference, either the upper or lower guide plate is moved simultaneously along the X and Y axes, so that the multiple needles inserted into the through holes are aligned in the same direction at the same time; the through holes have a preset length along the moving direction of the guide plates, and the positioning of the needles is controlled by adjusting the pressure on the inner surface of the guide plates; at least one pair of alignment holes with a certain distance between them and having a unidirectional length are provided on one side of the upper or lower guide plate, and when a pair of alignment holes is defined as a group, multiple groups of alignment holes with different directional lengths are provided; reference holes are provided on one side of the pad block between the upper and lower guide plates corresponding to the alignment holes respectively; With the reference pins inserted into one of the multiple sets of alignment holes and their corresponding reference holes, the upper guide plate is moved simultaneously along the X and Y axes according to the length direction of the alignment hole, with the plane as the reference. This allows multiple needles to be subjected to pressure applied by the upper guide plate in the direction of movement and to move along the diagonal direction, thereby achieving synchronous alignment of multiple needles. The system acquires the actual coordinate data of each needle tip in three-dimensional space through a high-precision visual positioning unit; applies multi-dimensional micro-displacement to the guide plate through a multi-axis linkage execution unit; monitors the contact stress distribution of the needle body within the through hole of the guide plate in real time through a distributed stress sensing unit; calculates the coordinated control command for each micro-actuator based on the deviation between the coordinate data acquired by the high-precision visual positioning unit and the preset target coordinates, combined with the stress information fed back by the distributed stress sensing unit, through a closed-loop control unit; drives the multi-axis linkage execution unit to perform compound micro-adjustment of the guide plate until the deviation between the actual coordinates and the target coordinates of all needle tips falls within the preset tolerance range, and the stress distribution uniformity monitored by the distributed stress sensing unit reaches the preset threshold; wherein, the multi-axis linkage execution unit includes at least 3 independently controlled micro-actuators, which are distributed asymmetrically around the upper and lower guide plates, and the distributed stress sensing unit is integrated at the contact interface between the guide plate and the needle body or at the force application end of the actuator; The high-precision visual positioning unit includes a confocal displacement sensor array and a high-speed area array image sensor. The confocal displacement sensor array is arranged in an oblique incidence manner to measure the axial height of the needle tip relative to the plane of the object being detected. The high-speed area array image sensor acquires a top-view image of the needle array from directly above and extracts the planar coordinates of each needle tip through a sub-pixel edge localization algorithm. The visual positioning unit spatially fuses the axial height data and the planar coordinate data to output the complete three-dimensional coordinates of each needle tip. Each micro-actuator in the multi-axis linkage actuator adopts a configuration combining piezoelectric ceramic drive and flexible hinge transmission; the piezoelectric ceramic driver provides displacement output with nanometer-level resolution; the flexible hinge converts the linear output of the piezoelectric ceramic into a push-pull force on a specific point on the edge of the guide plate; the three actuators are optimized according to the density distribution of the needle array and the rigidity characteristics of the guide plate to ensure that the guide plate can be controlled with a total of three degrees of freedom, including micro-rotation about two orthogonal axes in its plane and micro-translation along its normal direction. The distributed stress sensing unit uses a microelectromechanical system thin-film pressure sensor array; the sensor array is embedded in the inner wall of the through hole of the guide plate, and four independent sensitive elements are evenly distributed circumferentially on the inner wall of each through hole to detect the contact pressure between the needle body and the inner wall of the through hole at different positions. The distributed stress sensing unit integrates strain sensing elements directly into the output end of the micro-actuator; it inversely calculates the force exerted on the guide plate by measuring the micro-strain of the actuator output rod. The core control logic of the closed-loop control unit includes a two-stage decoupled controller. The first stage is the position loop controller, whose input is the deviation vector of the three-dimensional coordinates of each needle tip. Through a preset coordinate-actuator displacement transfer function matrix, the theoretical displacement of each group of micro-actuators is initially calculated. The second stage is the stress loop controller, whose input is the stress distribution uniformity index fed back by the distributed stress sensing unit. This index is obtained by calculating the ratio of the standard deviation to the mean of the stress at all sensitive points. The stress loop controller corrects the theoretical displacement output of the first stage based on this index. The correction strategy is to adjust the displacement of the actuator that plays a regulating role in the corresponding guide plate part when the stress distribution uniformity does not meet the standard. The specific execution flow of the Qi method includes: system initialization, the high-precision visual positioning unit performs the first three-dimensional scan of the needle module to obtain the initial coordinate set of the needle tip; the closed-loop control unit calculates the spatial deviation between the initial coordinate set and the target coordinate set; the multi-axis linkage execution unit performs the first collaborative fine-tuning according to the instructions of the closed-loop control unit; after fine-tuning, the high-precision visual positioning unit immediately performs the second three-dimensional scan, and the distributed stress sensing unit synchronously records the stress data; the closed-loop control unit compares the coordinate changes and stress changes of the two scans, and optimizes the parameters of its internal coordinate-actuator displacement transfer function matrix accordingly; this process is iterated until the convergence condition that the coordinate deviation of all needle tips is less than 2 micrometers and the stress distribution uniformity index is less than 0.1 is met simultaneously.

2. The method for aligning an electrical characteristic testing device with multi-directional contact points according to claim 1, characterized in that: The needles are preheated before pressure is applied to minimize the bending difference between multiple needles while increasing their strength.

3. The method for aligning an electrical characteristic testing device with multi-directional contact points according to claim 1, characterized in that: Let the value of the through hole diameter minus the needle diameter be value one, and the lateral distance from the vertex of the curved part of the needle with the largest curvature among multiple needles to the needle tip be value two. The movement range of the guide plate is controlled within the sum of value one and value two.

4. The method for aligning an electrical characteristic testing device with multi-directional contact points according to claim 1, characterized in that, The guide plate moves in the following direction: the midpoint of the angle formed between the virtual Y-axis with the center point of the through hole as the reference, from the zero point to the line connecting the needles closest to the Y-axis+ region and from the zero point to the line connecting the needles closest to the Y-axis- region.

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