High-speed optical detection platform for microprobe

Abstract

The invention relates to a high-speed optical detection platform for a microprobe. The high-speed optical detection platform comprises a machine base, the electromagnetic chuck is located above the machine table base and comprises a magnetic conductive frame and a magnetic conductive cover plate, a hollow structure is arranged in the magnetic conductive frame, an electromagnetic coil is installed in the hollow structure, an opening is formed in the upper portion of the magnetic conductive frame, and the magnetic conductive cover plate covers the opening side of the magnetic conductive frame. Magnetic lines of force generated by the electromagnetic coil form a closed magnetic circuit in the magnetic conductive frame and the magnetic conductive cover plate; and the detection lens is positioned above the magnetic conductive cover plate and can move up and down. According to the detection platform of the scheme, accurate focusing of the probe and efficient detection of the quality of the probe can be achieved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a high-speed optical detection platform for micro probes. Background Technology

[0002] Surface quality inspection of micro probes is a key step in the manufacturing process of pin cards. Its purpose is to screen out defective probes, improve the overall yield, thereby avoiding unnecessary welding costs and ensuring the final quality of pin cards.

[0003] Currently, this inspection is mainly divided into two methods: manual inspection and machine vision inspection. Due to limitations in accuracy, stability, and efficiency, manual inspection is widely adopted in the industry, typically using machine vision inspection methods, usually AOI (Automated Optical Inspection) technology. During the inspection process, because the probe is very small, it needs to be placed under a high-magnification lens to accurately locate defects. However, while high-magnification lenses improve resolution, they also introduce the problem of insufficient depth of field (depth of field ≤ 3μm), leading to significantly increased focusing difficulty and low inspection efficiency.

[0004] Traditional testing equipment uses a vacuum suction method on silicon wafers, where microprobes lie flat on the wafer and are adsorbed by vacuum. This method only ensures the flatness of the wafer but does not constrain warped probes, thus the overall flatness of the probes cannot be guaranteed, requiring frequent lens refocusing and affecting testing efficiency. Some equipment uses porous ceramics to improve the probe adsorption method, but this method only ensures that probes on the pores are adsorbed, leaving leaks in the pores not covered by probes. Further methods use air suction cups with precisely drilled holes according to the probe layout to fix the probes, but this method is difficult to design and extremely expensive to manufacture. It cannot flexibly track probe version iterations and cannot adjust the hole positions to adapt to warped frames. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide a detection platform capable of achieving precise focusing and high-speed detection.

[0006] Therefore, the present invention provides a high-speed optical detection platform for micro probes, comprising:

[0007] Machine base;

[0008] An electromagnetic chuck is located above the machine base. The electromagnetic chuck includes a magnetically conductive frame and a magnetically conductive cover plate. The magnetically conductive frame has a hollow structure inside, and an electromagnetic coil is installed inside the hollow structure. The upper part of the magnetically conductive frame has an opening, and the magnetically conductive cover plate covers the opening side of the magnetically conductive frame. When the electromagnetic coil is energized, the magnetic lines of force generated by the electromagnetic coil form a closed magnetic circuit in the magnetically conductive frame and the magnetically conductive cover plate.

[0009] The detection lens is located above the magnetic cover plate and is configured to move up and down.

[0010] In some embodiments, the magnetic cover plate and the magnetic frame are made of a high magnetic permeability material, and the magnetic permeability of the magnetic frame is greater than that of the magnetic cover plate.

[0011] In some embodiments, the magnetic cover plate is made of 430 stainless steel, silicon steel or permalloy, and the upper surface of the magnetic cover plate is mirror-polished, with an arithmetic mean deviation of less than or equal to 0.01 μm.

[0012] In some embodiments, in the projection onto a horizontal plane, the outer contour dimension of the magnetic cover plate is not less than the outer contour dimension of the magnetic frame.

[0013] In some embodiments, the magnetic cover plate and the magnetic frame are circular in projection onto a horizontal plane, and the magnetic frame has at least one iron core located at the center of the circle and a groove surrounding the iron core circumferentially; the electromagnetic coil is located in the groove and is formed by winding copper wire on the iron core.

[0014] In some embodiments, the magnetic cover plate includes a top plate and a side peripheral wall extending downward along the outer edge of the top plate, and the magnetic cover plate is sleeved on the outside of the magnetic frame.

[0015] In some embodiments, the magnetic cover plate has multiple notches on the lower edge of its side peripheral wall, and multiple radially extending screw holes are also provided on the side peripheral wall. The magnetic cover plate and the magnetic frame are locked together by screws.

[0016] In some embodiments, a dividing line is provided on the outer side of the upper surface of the magnetic cover plate along the circumferential direction. The distance between the dividing line and the outer edge of the top plate is equal to the thickness of the side wall. When the electromagnetic coil is energized, the magnetic lines of force in the area of ​​the magnetic cover plate within the dividing line are in the horizontal direction.

[0017] In some embodiments, the magnetic cover plate and the magnetic frame are detachably connected.

[0018] In some embodiments, the magnetic cover plate is a flat plate structure, and the magnetic cover plate is attached to the magnetic frame by electromagnetic force and gravity. The size range of the magnetic cover plate is 6-12 inches, and the thickness range of the magnetic cover plate is 2-30 mm.

[0019] In some embodiments, the machine base includes a movable platform and a fixed base. The movable platform is movable relative to the fixed base along the X-axis and Y-axis, and rotates about the Z-axis. The magnetic guide frame is fixedly mounted on the movable platform.

[0020] In some embodiments, when the electromagnetic coil is energized, a high-density horizontal magnetic field is formed in the near-surface region of the magnetically conductive cover plate, with magnetic field lines pointing horizontally from the center of the magnetically conductive cover plate to the outer periphery, or the magnetic field lines pointing horizontally from the outer periphery of the magnetically conductive cover plate to the center.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention utilizes an electromagnetic chuck to quickly fix a large number of micro probes, reducing their warpage and ensuring a flat fixation on the chuck surface. This keeps the focal plane of the inspection lens constant, avoiding frequent refocusing and enabling high-speed, automated optical inspection. Furthermore, by connecting the inner and outer magnetic frames of the electromagnetic coil with a magnetically conductive cover, the magnetic field lines, originally perpendicular to the fixture surface, are successfully readjusted to be primarily parallel to the fixture surface. This magnetic circuit reconstruction allows a high-intensity regional magnetic field to form in the horizontal direction close to the fixture, establishing an extremely uniform and stable magnetic field distribution. This design fundamentally eliminates workpiece tilting or stress concentration problems caused by uneven magnetic fields, enabling precise focusing of probes and high-speed, high-precision quality inspection under high-magnification lenses. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a high-speed optical detection platform for a micro probe provided in an embodiment of this application.

[0024] Figure 2 This is a schematic diagram of the magnetic field distribution structure of the electromagnetic coil before the magnetic cover is installed.

[0025] Figure 3 This is a front view of the magnetic cover plate provided in an embodiment of this application.

[0026] Figure 4 This is a side view of the magnetic cover plate provided in an embodiment of this application.

[0027] Figure 5 This is a schematic diagram of the magnetic field distribution of a single-core structure provided in an embodiment of this application.

[0028] Figure 6 This is a schematic diagram of a single-layer surrounding structure provided in an embodiment of this application.

[0029] Figure 7 This is a schematic diagram of the planar structure of the double-layered surrounding structure provided in the embodiment of this application.

[0030] Figure 8 This is a three-dimensional structural diagram of the double-layered surrounding structure provided in an embodiment of this application.

[0031] Figure 9 This is a schematic diagram of the magnetic field distribution of the double-layered surrounding structure provided in an embodiment of this application.

[0032] Among them, 100, testing platform; 1, machine base; 11, moving platform; 12, fixed seat; 2, electromagnetic chuck; 21, magnetic cover plate; 211, top plate; 212, dividing line; 213, electromagnet storage slot; 214, electromagnet wire outlet; 215, bayonet; 22, magnetic frame; 201, electromagnetic coil; 202, iron core; 203, side wall; 204, bottom wall; 205, primary iron core; 206, secondary iron core; 3, testing lens. Detailed Implementation

[0033] To illustrate the technical content, structural features, achieved objectives, and effects of the invention in detail, the technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. In the following description, for illustrative purposes, numerous specific details are set forth to provide a detailed description of various exemplary embodiments or implementations of the invention. However, various exemplary embodiments may also be implemented without these specific details or in one or more equivalent arrangements. Furthermore, the various exemplary embodiments may differ, but are not necessarily exclusive. For example, the specific shape, construction, and characteristics of the exemplary embodiments may be used or implemented in another exemplary embodiment without departing from the inventive concept.

[0034] In this application, unless otherwise expressly specified and limited, the term "connection" shall be interpreted broadly. For example, "connection" may be a fixed connection, a detachable connection, or an integral part; it may be a direct connection or an indirect connection through an intermediate medium.

[0035] The positional relationships of the "X-axis", "Y-axis", and "Z-axis" described in this manual are respectively... Figure 1The X, Y, and Z axes correspond to each other. Furthermore, in this application, spatial relative terms such as "below," "under," "below," "down," "above," "above," "higher," and "side" (e.g., in a "sidewall") are used to describe the relationship between one element and another (other) element as shown in the figures. Spatial relative terms are intended to include different orientations of the device in use, operation, and / or manufacture other than those depicted in the figures. For example, if the device in the figures is flipped, an element described as "below" or "under" other elements or features would then be positioned "above" those other elements or features. Therefore, the exemplary term "below" can include both above and below orientations.

[0036] The micro probes used on the probe cards for wafer inspection have micromagnetism. Due to the large number of micro probes, in order to improve the efficiency of batch inspection of micro probes, the applicant expects to design an automated optical inspection platform that can adsorb and fix multiple micro probes at one time using an electromagnetic chuck and inspect the micro probes by means of AOI (Automated Optical Inspection).

[0037] See details Figure 1 This application proposes a high-speed optical inspection platform 100 for miniature probes, including a base 1, an electromagnetic chuck 2 located above the base 1, an inspection lens 3 located above the electromagnetic chuck 2, an imaging device, an image processing unit, and a computer, etc.

[0038] The machine base 1 includes a movable platform 11 and a fixed base 12. The movable platform 11 can move relative to the fixed base 12 along the X-axis and Y-axis, and rotate around the Z-axis.

[0039] The electromagnetic chuck 2 is used to provide a magnetic field to fix miniature probes in batches for optical inspection. The electromagnetic chuck 2 includes a magnetically conductive frame 22 fixedly mounted on a moving platform 11. The magnetically conductive frame 22 is hollow and contains an electromagnetic coil 201. The electromagnetic coil generates a magnetic field when energized, such as... Figure 2 As shown, it can be seen that an electromagnetic chuck without special design can achieve overall adsorption of the entire probe surface, but the magnetic field strength distribution is uneven throughout, as shown in the figure. Figure 2As indicated by the arrows, the magnetic field lines at the edge of the coil are dense and oriented almost perpendicular to the surface, resulting in a strong magnetic force there. However, the magnetic field lines at the center and above the coil are unusually sparse, significantly weakening the magnetic force. This significant unevenness in direction and density prevents the electromagnetic chuck from providing a uniform and consistent attraction force for the tens of thousands of micrometer-sized probes. With a 20x detection lens (depth of field less than 3μm), this uneven attraction directly prevents the probe plane from being uniformly aligned with the focal plane, thus hindering high-speed AOI detection of probe appearance and size at high magnification.

[0040] Therefore, the electromagnetic chuck 2 of this application is also designed with a magnetically conductive cover plate 21 that matches the magnetically conductive frame 22. Both the magnetically conductive cover plate 21 and the magnetically conductive frame 22 are made of high magnetic permeability material. When the electromagnetic coil is energized, the magnetic lines of force generated by the electromagnetic coil form a closed magnetic circuit in the magnetically conductive frame and the magnetically conductive cover plate, so that a high-density horizontal magnetic field is formed in the near-surface area (within 1-2mm height) of the magnetically conductive cover plate. This readjusts the magnetic lines of force perpendicular to the surface of the coil edge to be horizontal and makes them cross the surface of the coil with ultra-low magnetic force, forming a high-strength horizontal magnetic field close to the horizontal surface of the fixture. This allows the tens of thousands of probes to be "laid flat" on the surface of the fixture by magnetic attraction, so that the inspection lens can perform high-speed AOI inspection.

[0041] The detection lens 3 is located above the magnetic cover plate 21 and can move up and down to achieve precise focusing, ensuring that high-quality probe images with clear edges and distinct features are captured.

[0042] The imaging device is used to image the optical image acquired by the detection lens, the image processing unit is used to perform image recognition, judgment, and calculation processing, and the computer is used to provide a human-computer interaction interface for inputting detection parameters, displaying detection results, etc. In some embodiments, the detection lens 3 can also be an optical camera module or a fiber optic camera that integrates an optical lens and an imaging device. Since most components of AOI detection technology, such as the detection lens and imaging device, can be purchased through market channels, this patent will not elaborate on them further.

[0043] In one embodiment of this application, the design standard for the electromagnetic coil is: rated voltage 12-48V, and temperature rise to no more than 80°C within 24 hours. See also Figure 5-8 As shown, the magnetically conductive frame 22 has an opening at the top and at least one iron core 202 located at the center and a groove surrounding the iron core in the circumferential direction; the electromagnetic coil 201 is located in the groove and is made by winding copper wire on the iron core, or the wound coil is fixed to the iron core of the magnetically conductive frame by epoxy resin.

[0044] In one embodiment of this application, see Figure 1 , Figure 9The magnetic cover plate 21 adopts a flat plate structure that can be disassembled when power is off, allowing the entire probe to be pre-released on the cover plate surface before loading and unloading. This can be achieved manually or automatically by mechanical grippers or suction cups. In this embodiment, the outer diameter of the magnetic cover plate 21 is equal to that of the magnetic frame 22. The magnetic cover plate 21 covers the opening side of the magnetic frame 22 and is attached to the magnetic frame 22 by electromagnetic force and gravity. The magnetic cover plate 21 and the magnetic frame 22 are detachably connected. When the electromagnetic coil is energized, the magnetic cover plate 21 and the magnetic frame 22 are magnetically attracted and fixed. When the electromagnetic coil is de-energized, there is no fixed connection between the magnetic cover plate 21 and the magnetic frame 22, and they can be easily separated.

[0045] In this embodiment, both the magnetic cover plate 21 and the magnetic frame 22 are made of high permeability materials (such as 430 stainless steel, silicon steel, or permalloy). This allows for efficient magnetic conduction and confinement of the magnetic field, while also maintaining a long service life in semiconductors. Furthermore, the permeability of the magnetic frame 22 is greater than that of the magnetic cover plate 21. To achieve high specular reflectivity to the light source and present a bright primary color under high-magnification optical lenses, the upper surface of the magnetic cover plate 21 undergoes mirror-level polishing and electroplating. Polishing ensures that the arithmetic mean deviation of the upper surface profile Ra is ≤0.01μm, thus distinguishing it from the dark and rough electroplated surface of the probe and providing higher contrast. Electroplating removes machining marks, avoiding false detections and enabling accurate probe identification.

[0046] In one embodiment, the magnetic cover plate 21 has a size ranging from 6 to 12 inches and a thickness ranging from 2 to 30 mm. The corresponding magnetic frame 22 has the same thickness as the magnetic cover plate 21 and a height ranging from 5 to 100 mm.

[0047] In this embodiment, a partitioned focusing scheme is adopted during detection. This scheme first divides the detection area into several sub-regions and uses the needle at the center of each region as the focus point for individual focusing. Then, based on the focusing data, a high-speed shooting detection is performed in the same region, so that high-speed focusing and detection can be achieved even when the flatness of the fixture is within 10-20μm.

[0048] In another embodiment of this application, see Figures 3-4 In the projection on the horizontal plane, the outer contour dimension of the magnetic cover plate 21 is larger than the outer contour dimension of the magnetic frame 22, and the magnetic cover plate 21 and the magnetic frame 22 are circular in the projection on the horizontal plane.

[0049] The magnetic cover plate 21 includes a top plate 211 and a side peripheral wall 203 extending downward along the outer edge of the top plate 211. The magnetic cover plate 21 is fitted onto the outside of the magnetic frame 22. An electromagnet receiving groove 213 is provided inside the magnetic cover plate 21. The size of the receiving groove is designed according to the magnetic frame 22, and it is 1-2 mm higher than the magnetic frame 22, and its diameter is 2 mm larger than that of the magnetic frame 22.

[0050] The side wall 203 has corresponding slots 215 on both sides, with the openings facing downwards to prevent fingers or grippers from touching the machine and to facilitate loading and unloading. The size is designed according to the size of the fingers or grippers, and whether the bottom is open can be selected according to the specific situation. The side wall 203 also has an electromagnetic coil outlet 214 facing downwards for the electromagnetic coil to exit.

[0051] In another embodiment, the side peripheral wall 203 is used to laterally fix the magnetic cover plate and the magnetic frame, and can be horizontally locked and fixed to the magnetic frame 22 from the side using three or more bolts.

[0052] A dividing line 212 is provided along the circumferential direction on the outer side of the upper surface of the magnetic cover plate 21. This dividing line 212 is used to distinguish between the magnetic area (inner) and the non-magnetic area (outer periphery), ensuring that the probe to be tested is within the magnetic area. This line should not be too deep, as this would affect the structural strength. The thickness of the magnetic area is the same as that of the electromagnet cover plate, 4-20mm, and the surface flatness is 3μm. Inside the dividing line, the magnetic lines of the electromagnetic chuck are roughly evenly distributed and the direction of the magnetic lines is horizontal, while outside the dividing line, the direction of the magnetic lines is perpendicular to the direction of the outer peripheral wall. When placing the probe, it should be ensured that the probe is evenly placed within the dividing line (magnetic area), while the non-adsorption area outside the dividing line can achieve a magnetic shielding effect, without interfering with the operation of components such as the motor and lead screw. In this embodiment, the distance between the dividing line 212 and the outer edge of the top plate 211 is equal to the thickness of the side peripheral wall 203.

[0053] In this embodiment, see Figures 5-9 The magnetically conductive frame 22 can adopt a split magnetic circuit structure, and can adopt a single-core structure, a two-layer structure, or a three-layer structure, etc. See [reference needed]. Figure 2 and Figure 5 , Figure 5 It has a single-core structure, including a core 202 at the center and a groove surrounding the outer side of the core, with a single coil disposed within the groove; when the electromagnetic coil 201 is energized, the magnetic lines of force generated by the electromagnetic coil 201 form a closed magnetic circuit in the magnetically conductive frame 22 and the magnetically conductive cover plate 21. Figure 1 As shown, Figure 1The arrows in the diagram represent magnetic circuits. The magnetically conductive cover plate 21 readjusts the magnetic field lines perpendicular to the surface of the coil edge to a horizontal position, allowing them to cross the surface of the ultra-low magnetic field coil. The magnetic field lines originate from the center of the electromagnetic coil 201, extend radially symmetrically through the magnetically conductive cover plate 21, flow back through the outer peripheral wall of the magnetically conductive frame 22, and are radially conducted to the iron core 202 of the magnetically conductive frame 22, forming a closed magnetic circuit. The magnetic field lines in this magnetic field are parallel and dense, with minimal magnetic leakage. On the surface of the magnetically conductive cover plate 21, the magnetic field lines are uniformly arranged, the vertical component is effectively suppressed, and the lateral continuity is enhanced, constructing a stable, low-distortion magnetic induction region. This ensures that the micron-sized probe experiences consistent force throughout the entire region, meeting the requirement for neat adsorption of large-area micron-sized probes.

[0054] In another embodiment, such as Figure 6 As shown, an example of a two-layer structure for the magnetically conductive frame is provided. Based on a single-core structure, multiple primary cores 205 are added, distributed around the core 202. Each primary core 205 has the same shape and size, with a cross-sectional area smaller than the core 202. Each core 202 and each primary core 205 has an independently wound sub-coil. These sub-coils are typically connected in series or parallel, ensuring that all coils are wound in the same direction. Multiple sub-coils can be wound using planetary winding. When energized, magnetic lines of force originate from the coil wound on the core 202 and enter the magnetically conductive cover plate 21 upwards. Inside the magnetically conductive cover plate 21, the magnetic lines of force extend horizontally and radially outwards symmetrically. After reaching the position corresponding to the primary core 205, the magnetic lines of force enter the primary core 205 downwards. The magnetic lines of force flow radially back to the core 202 through the magnetically conductive frame 22, forming a complete closed loop. This structure forms a powerful main magnetic circuit, with a dense and parallel magnetic field in the central region, which can meet the requirements for the neat adsorption of large-area micron-sized probes.

[0055] In another embodiment, such as Figures 7-9 As shown, an example of a three-layer magnetic guide frame is provided. Based on a two-layer structure, multiple secondary iron cores 206 are added, arranged around the primary iron core 205. Each secondary iron core 206 has the same shape and size, with a cross-sectional area smaller than the iron core 202 but larger than the primary iron core 205. Independent sub-coils are wound on the iron core 202, the primary iron core 205, and the secondary iron core 206. All coils are typically connected in series or parallel, using a planetary winding method, following an alternating magnetic pole pattern to ensure a correct magnetic circuit (e.g., the upper end of iron core 202 is the N pole, the upper end of the primary iron core 205 is the S pole, the upper end of the secondary iron core 206 is the N pole, and the outer peripheral wall of the magnetic guide frame serves as the final return path; the part of its top that contacts the magnetic guide cover plate 21 is the S pole relative to the inner side). The magnetic field line path is as follows... Figure 9As shown, the inner circuit is closed in the magnetic cover plate 21 and the magnetic frame, and the outer circuit can maintain a high-density horizontal magnetic field in the near-surface area of ​​the magnetic cover plate 21, so as to achieve neat adsorption of large-scale dense probes. The electromagnet core has high permeability and almost no magnetic field leakage. It achieves magnetic shielding effect in the non-adsorption area and does not interfere with the operation of components such as motors and lead screws.

[0056] The single-coil winding, series winding, and parallel winding mentioned above are respectively:

[0057] Single-coil winding method: One or more copper wires are tightly and multi-layered wound on the iron core 202. This structure has strong integrity and a concentrated magnetic field, which can generate a strong vertical magnetic field component. After being guided by the magnetic guide cover plate 21, it finally forms a horizontal magnetic field with high intensity and strong penetration on the surface of the fixture. This winding method is particularly suitable for testing scenarios where the fixture is thick, the diameter-to-height ratio is small, and a large adsorption force is required.

[0058] Multi-coil series winding method: Sub-coils are wound on each of the two- or three-layer iron cores (including iron core 202, primary iron core 205, and secondary iron core 206). These sub-coils are connected end-to-end by wires to form a single series circuit. This connection method ensures that all sub-coils have equal current and synchronously established magnetic fields; the total magnetomotive force is the sum of the magnetomotive forces of each sub-coil. This method has a simple structure and is suitable for applications with relatively thin fixtures, large diameter-to-height ratios, and requiring moderate or low adsorption force.

[0059] Multi-coil parallel winding method: Sub-coils are wound on each iron core in a two- or three-layer structure. The beginning of all sub-coils is connected to one pole of the power supply, and the end is connected to the other pole, forming multiple parallel current paths. The advantage of this connection method is that, in addition to being suitable for scenarios with small thickness and large diameter-to-height ratio, it also allows for controllable adjustment of the magnetic attraction area by independently controlling the on / off state of the sub-coils. This flexibly adapts to the adsorption needs of probe arrays of different sizes or layouts, significantly improving the flexibility and energy efficiency of equipment applications.

[0060] Different winding methods are selected based on the thickness of the probe fixture, its diameter-to-height ratio, and the required adsorption force, among other working conditions.

[0061] In this embodiment, the magnetically conductive frame 22 operates on the principle of minimum magnetic resistance, where magnetic field lines tend to close along the path of least magnetic resistance. The magnetically conductive frame 22 is made of a high-permeability material, and its internal magnetic domains tend to align under the influence of an external magnetic field, forming a low-resistance path. This guides the magnetic field lines along a predetermined path for efficient conduction, reducing magnetic leakage and enhancing the uniformity of the magnetic field on the fixture surface, thereby significantly improving the adsorption accuracy and reliability of the micro-probes. This magnetic circuit design forms a closed magnetically conductive path when energized, ensuring that the magnetic field energy is concentrated on the working surface, further reducing energy consumption and improving response speed. Upon power-off, the magnetic circuit is immediately decoupled, facilitating the overall transfer and rapid replacement of the probe array, improving detection efficiency. Combined with a high-permeability magnetically conductive cover plate, it provides a stable magnetic adsorption constraint for the probes. The mirror-polished surface effectively eliminates the interference of machined textures on visual inspection. The synergistic effect of magnetic constraint and optical mirrors supports the entire probe array in achieving rapid and stable autofocus and defect identification within a 20x magnification depth of field.

[0062] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope. The scope of protection of the present invention is defined by the appended claims, specification, and their equivalents.

Claims

1. A high-speed optical detection platform for micro probes, characterized in that, include: Machine base; An electromagnetic chuck is located above the machine base. The electromagnetic chuck includes a magnetically conductive frame and a magnetically conductive cover plate. The magnetically conductive frame has a hollow structure inside, and an electromagnetic coil is installed inside the hollow structure. The upper part of the magnetically conductive frame has an opening, and the magnetically conductive cover plate covers the opening side of the magnetically conductive frame. When the electromagnetic coil is energized, the magnetic lines of force generated by the electromagnetic coil form a closed magnetic circuit in the magnetically conductive frame and the magnetically conductive cover plate. The detection lens is located above the magnetic cover plate and is configured to move up and down.

2. The detection platform according to claim 1, characterized in that, The magnetic cover plate and the magnetic frame are made of high magnetic permeability material, and the magnetic permeability of the magnetic frame is greater than that of the magnetic cover plate.

3. The detection platform according to claim 2, characterized in that, The magnetic cover plate is made of 430 stainless steel, silicon steel or permalloy, and the upper surface of the magnetic cover plate is mirror-polished, with an arithmetic mean deviation of less than or equal to 0.01μm.

4. The detection platform according to claim 1, characterized in that, In the projection onto the horizontal plane, the outer contour dimension of the magnetic cover plate is not less than the outer contour dimension of the magnetic frame.

5. The detection platform according to claim 1, characterized in that, The magnetic cover plate and the magnetic frame are circular in the projection of the horizontal plane. The magnetic frame has at least one iron core located at the center of the circle and a groove surrounding the iron core in the circumferential direction. The electromagnetic coil is located in the groove.

6. The detection platform according to claim 5, characterized in that, The magnetic cover plate includes a top plate and a side peripheral wall extending downward along the outer edge of the top plate, and the magnetic cover plate is sleeved on the outside of the magnetic frame.

7. The detection platform according to claim 6, characterized in that, The magnetic cover plate has multiple notches on the lower edge of its side wall, and multiple radially extending screw holes are also provided on the side wall. The magnetic cover plate and the magnetic frame are locked together by screws.

8. The detection platform according to claim 1, characterized in that, The outer side of the upper surface of the magnetic cover plate is provided with a dividing line along the circumferential direction. When the electromagnetic coil is energized, the magnetic lines of force in the area of ​​the magnetic cover plate within the dividing line are in the horizontal direction.

9. The detection platform according to claim 1, characterized in that, The magnetic cover plate and the magnetic frame are detachably connected.

10. The detection platform according to claim 9, characterized in that, The magnetic cover plate is a flat plate structure, and it is attached to the magnetic frame by electromagnetic force and gravity. The size range of the magnetic cover plate is 6-12 inches, and the thickness range is 2-30 mm.

11. The detection platform according to any one of claims 1-10, characterized in that, The machine base includes a movable platform and a fixed base. The movable platform can move relative to the fixed base along the X-axis and Y-axis, and rotate about the Z-axis. The magnetic guide frame is fixedly installed on the movable platform.

12. The detection platform according to any one of claims 1-10, characterized in that, When the electromagnetic coil is energized, a high-density horizontal magnetic field is formed in the near-surface area of ​​the magnetically conductive cover plate. The magnetic lines of force point horizontally from the center of the magnetically conductive cover plate to the outer periphery, or the magnetic lines of force point horizontally from the outer periphery of the magnetically conductive cover plate to the center.

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