Wafer testing apparatus and method of controlling the same

Abstract

The application discloses a wafer testing device and a control method thereof. The wafer testing device comprises a bearing table, a lifting mechanism, a camera device and a laser device. The bearing table is provided with a testing position for placing a wafer. The lifting mechanism is installed on the bearing table in a lifting manner. The camera device is installed on the lifting mechanism, and a camera end of the camera device faces the testing position. The camera device is used to acquire image information of the wafer placed on the testing position. The laser device is installed on the lifting mechanism, and a light-emitting end of the laser device faces the testing position. The laser device is used to emit testing laser to the wafer placed on the testing position. The laser focus emitted by the laser device is higher than a visual focusing surface of the camera device. The wafer testing device solves the problem that the laser device is prone to colliding with a carrier or a clamp on the bearing table due to careless operation.

Description

Technical Field

[0001] This invention relates to the field of wafer testing technology, and in particular to a wafer testing device and its control method. Background Technology

[0002] In existing technologies, automated equipment integrating visual positioning systems and laser processing systems is commonly used to measure the thickness, thickness variations at different locations, and warpage of wafers. Such equipment typically includes a platform for placing the wafer, a lifting mechanism, and a camera and laser unit mounted on the lifting mechanism. During operation, the camera first focuses on the wafer surface to obtain precise wafer image information, and then the laser unit emits a laser beam based on this image information to perform the test.

[0003] In existing testing equipment, the physical installation position of the laser device is limited to a relatively low height. When mounting or changing carriers or fixtures for fixing wafers of different sizes on the platform, or due to improper operation by the operator, the low-positioned laser device is highly susceptible to accidental collisions with these carriers or fixtures during the movement of the lifting mechanism. Such collisions can not only damage the expensive laser device and carriers, causing equipment downtime and affecting production efficiency, but may also introduce testing errors due to laser head optical path misalignment, or even cause wafer breakage. Summary of the Invention

[0004] The main objective of this invention is to provide a wafer testing device that addresses the technical problem of laser devices being easily damaged by collisions.

[0005] To achieve the above objectives, the wafer testing equipment proposed in this invention includes:

[0006] A support platform, wherein the support platform is provided with test positions for placing wafers;

[0007] A lifting mechanism is mounted on the support platform in a height-reducible manner;

[0008] A camera device is mounted on the lifting mechanism, with the camera end of the camera device facing the test position, and the camera device is used to acquire image information of the wafer placed on the test position;

[0009] A laser device is mounted on the lifting mechanism, with the light-emitting end of the laser device facing the test position, and the laser device is used to emit a test laser toward the wafer placed on the test position;

[0010] The laser emitted by the laser device has a focal point higher than the visual focal plane of the camera device.

[0011] Optionally, the height difference between the laser focal point emitted by the laser device and the visual focal plane of the camera device is set to 20mm to 30mm.

[0012] Optionally, the laser device can be mounted at an adjustable height on the lifting mechanism.

[0013] Optionally, the wafer testing equipment further includes a mounting base installed on the lifting mechanism. The mounting base is provided with a connecting boss, which includes a fixed part and a spring arm part. The spring arm part has a fixed end and a detachable end. The fixed end is connected to one end of the fixed part. The middle part of the spring arm part and the middle part of the fixed part form a mounting hole. The detachable end is detachably connected to the other end of the fixed part. The laser device is installed in the mounting hole. When the detachable end is connected to the fixed part, the spring arm part presses the laser device tightly against the mounting hole. When the detachable end is separated from the fixed part, the spring arm part releases the laser device.

[0014] Optionally, the detachable end has a through hole, and the fixing part has a fixing hole corresponding to the through hole, and the through hole and the fixing hole are connected by fasteners.

[0015] Optionally, the wafer testing equipment further includes a wafer carrier, which is installed at the test position and is used to carry the wafer. The lifting mechanism has a minimum preset position on the lifting trajectory. When the lifting mechanism is at the minimum preset position, a preset anti-collision distance is formed between the laser device and the wafer carrier.

[0016] Optionally, the wafer testing equipment further includes a driving device, a control unit, and a position sensor. The driving device and the position sensor are both electrically connected to the control unit. The driving device is used to drive the lifting mechanism to move up and down. The position sensor is installed on the lifting mechanism and is used to detect the current position of the lifting mechanism. The control unit is used to control the driving device to stop running when the current position of the lifting mechanism reaches the minimum preset position.

[0017] Optionally, the support platform is provided with a limiting structure, which is used to cooperate with the lifting mechanism to limit the lifting mechanism from continuing to descend when the lifting mechanism reaches the minimum preset setting.

[0018] The present invention also proposes a control method for a wafer testing device, for controlling the wafer testing device as described above, the control method comprising the following steps:

[0019] Get test commands;

[0020] According to the test command, control the lifting mechanism to descend to the first preset position;

[0021] Confirm that the lifting mechanism is in the first preset position, and control the camera device to operate;

[0022] The lifting mechanism is controlled to descend from a first preset position to a second preset position, wherein the height difference between the first preset position and the second preset position is equal to the height difference between the laser focal point emitted by the laser device and the visual focal plane of the camera device;

[0023] Confirm that the lifting mechanism is in the second preset position, and control the operation of the laser device.

[0024] Optionally, after confirming that the lifting mechanism is in the second preset position and controlling the operation of the laser device, the method further includes:

[0025] The lifting mechanism is controlled to descend from a second preset position to a third preset position, wherein the height difference between the second preset position and the third preset position is less than or equal to the thickness of the wafer, so that the laser focus emitted by the laser device falls on the lower surface of the wafer.

[0026] Confirm that the lifting mechanism is in the third preset position, and control the operation of the laser device.

[0027] The wafer testing equipment of this invention solves the problem of laser devices easily colliding with carriers or fixtures on the support stage due to accidental operation. By adjusting the relative height between the laser device and the camera device, the installation position of the laser device can be appropriately raised, thereby naturally forming a safe distance between it and the carrier during testing and operation. This design does not require additional anti-collision structures; the anti-collision effect can be achieved simply by optimizing the optical system layout, offering advantages such as low implementation cost and high reliability. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the wafer testing equipment of the present invention;

[0030] Figure 2 A partial structural schematic diagram of the invented wafer testing equipment;

[0031] Figure 3A cross-sectional schematic diagram of a partial structure of the invented wafer testing equipment;

[0032] Figure 4 This is a schematic diagram of the installation of the laser device in this invention;

[0033] Figure 5 This is a cross-sectional view of the connecting boss in this invention.

[0034] Explanation of icon numbers:

[0035]

[0036] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0039] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the word "and / or" throughout the text means including three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0040] This invention proposes a wafer testing device to solve the technical problem that laser devices are easily damaged by collisions.

[0041] In embodiments of the present invention, such as Figures 1 to 3As shown, the wafer testing equipment includes: a support platform 10, which has a test position for placing wafers; a lifting mechanism 20, which is movably mounted on the support platform 10; a camera device 30, which is mounted on the lifting mechanism 20, with its camera end facing the test position, and is used to acquire image information of the wafer placed on the test position; and a laser device 40, which is mounted on the lifting mechanism 20, with its light-emitting end facing the test position, and is used to emit a test laser towards the wafer placed on the test position; wherein the laser focal point emitted by the laser device 40 is higher than the visual focusing surface 31 of the camera device 30.

[0042] In this embodiment, the lifting mechanism 20 can adopt a lead screw and slider structure. A motor drives the lead screw to rotate, causing the slider to move up and down, thereby achieving the lifting and lowering of the camera device 30 and the laser device 40. The camera device 30 is fixedly mounted on the lifting mechanism 20, with its camera end facing the test position. The camera device 30 is used to acquire image information of the wafer placed on the test position for accurate identification of the wafer's position and shape. The laser device 40 is also fixedly mounted on the lifting mechanism 20, with its light-emitting end also facing the test position. The laser device 40 is used to emit a test laser onto the wafer placed on the test position to measure parameters such as thickness and warpage.

[0043] The focal point of the laser beam emitted by the laser device 40 is located at a higher vertical height than the optimal focusing plane of the camera device 30 when acquiring images of the wafer surface. This can be achieved by adjusting the installation position of the laser device 40. The focal point of the laser emitted by the laser device 40 is higher than the visual focusing surface 31 of the camera device 30. For example, the laser focal point can be a certain distance higher than the visual focusing surface 31 of the camera device 30. This arrangement allows the overall installation position of the laser device 40 to be raised accordingly, naturally creating a safe distance between it and the carrier.

[0044] By setting a height difference between the laser focus and the visual focusing surface 31, the laser device 40 is prevented from descending excessively to the vicinity of the wafer carrier surface. This avoids collisions between the laser device 40 and the carrier or fixture on the stage 10 during wafer carrier installation or wafer replacement. This design ensures the effectiveness of laser testing while directly eliminating the risk of collisions during equipment operation through physical height misalignment.

[0045] When the wafer testing equipment is in operation, the lifting mechanism 20 is first lowered so that the camera device 30 focuses on the wafer surface and acquires image information. Then, the lifting mechanism 20 continues to descend a certain distance so that the laser focus of the laser device 40 falls on the wafer surface for laser testing. Because the initial position of the laser device 40 is relatively high, a safe distance is maintained between it and the carrier throughout the entire process.

[0046] Through the above solution, this application solves the problem that the laser device 40 is prone to collision with the carrier or clamp on the support platform 10 due to accidental operation. By adjusting the relative height relationship between the laser device 40 and the camera device 30, the installation position of the laser device 40 can be appropriately raised, thereby naturally forming a safe distance between it and the carrier during testing and operation. This design does not require additional anti-collision structures; the anti-collision effect can be achieved simply by optimizing the optical system layout, offering advantages such as low implementation cost and high reliability.

[0047] For example, such as Figure 3 As shown, the height difference h between the laser focal point emitted by the laser device 40 and the visual focusing surface 31 of the camera device 30 is set to 20mm to 30mm, for example, it can be 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm or 30mm.

[0048] The height difference between the laser focus and the visual focusing surface 31 is controlled within the range of 20mm to 30mm. This range is optimized by balancing the relationship between the installation height and the lifting displacement. For example, when the height difference is 25mm, the laser device 40 can be installed at a relatively high position on the lifting mechanism 20 to avoid interference with the wafer carrier. At the same time, after the camera device 30 completes focusing, the lifting mechanism 20 only needs to descend 25mm to make the laser focus contact the wafer surface, reducing the lifting stroke.

[0049] During wafer testing, the camera device 30 first focuses on the wafer surface to acquire image information. After acquiring the image information, since the laser focus is preset to be 3120mm to 30mm above the visual focusing plane, the lifting mechanism 20 needs to descend to the corresponding height difference to align the laser focus with the wafer. When the height difference h is within this range, the mounting position of the laser device 40 is raised to avoid collision with the wafer carrier; at the same time, the descent stroke of the lifting mechanism 20 is shortened, improving testing efficiency.

[0050] The above technical solution ensures that the 20mm to 30mm height difference provides sufficient installation space for the laser device 40 without requiring excessive displacement adjustment of the lifting mechanism 20. Therefore, this solution improves equipment operating efficiency and safety while maintaining testing accuracy.

[0051] For example, the laser device 40 is height-adjustably mounted on the lifting mechanism 20. When it is necessary to adapt to wafer carriers of different thicknesses, the height of the laser device 40 can be adjusted individually, ensuring that the laser focus is always aligned with the wafer. By adjusting the height of the laser device 40, collisions with the wafer carrier or fixture can be effectively avoided, reducing the risk of equipment damage and improving the safety of the testing process. Furthermore, the height-adjustable design enhances the equipment's adaptability to different working conditions, expands its application range, and improves its versatility and practicality.

[0052] For example, such as Figure 4 and Figure 5 As shown, the wafer testing equipment also includes a mounting base 50 installed on the lifting mechanism 20. The mounting base 50 is provided with a connecting boss 51. The connecting boss 51 includes a fixing part 52 and a spring arm part 53. The spring arm part 53 has a fixed end 531 and a detachable end 532. The fixed end 531 is connected to one end of the fixing part 52. The middle part of the spring arm part 53 and the middle part of the fixing part 52 form a mounting hole 54. The detachable end 532 is detachably connected to the other end of the fixing part 52. The laser device 40 is installed in the mounting hole 54. When the detachable end 532 is connected to the fixing part 52, the spring arm part 53 presses the laser device 40 into the mounting hole 54. When the detachable end 532 is separated from the fixing part 52, the spring arm part 53 releases the laser device 40.

[0053] The mounting base 50 is fixed to the preset mounting position of the lifting mechanism 20 by bolts or clips. The fixing part 52 of the connecting boss 51 and the spring arm part 53 can be integrally formed or assembled separately. The fixed end 531 of the spring arm part 53 is connected to one end of the fixing part 52 by welding, riveting or integral forming process, and the detachable end 532 is connected to the other end of the fixing part 52 through a threaded hole, in which screws or pins can be installed. The diameter of the mounting hole 54 can be set to be slightly smaller than the outer diameter of the laser device 40.

[0054] When the height of the laser device 40 needs to be adjusted, the detachable end 532 of the spring arm 53 separates from the fixed part 52. At this time, the spring arm 53 opens outward due to elastic restoring force, the diameter of the mounting hole 54 enlarges, the friction between the laser device 40 and the inner wall of the mounting hole 54 decreases, and the laser device 40 can move up and down along the axis of the mounting hole 54 to the target position. After the adjustment is completed, the detachable end 532 of the spring arm 53 moves closer to the fixed part 52, the spring arm 53 undergoes elastic bending deformation, the diameter of the mounting hole 54 shrinks, and the laser device 40 is tightly wrapped by the radial pressure generated by the spring arm 53.

[0055] The above technical solution enables rapid height adjustment and stable fixation of the laser device 40. This simplifies the height adjustment process and improves adjustment efficiency. Simultaneously, the elastic clamping mechanism of the spring arm 53 ensures the stability of the laser device 40 after installation, preventing positional displacement caused by the movement of the lifting mechanism 20 or external vibrations. Furthermore, this design reduces the potential for insecure installation during frequent disassembly and relocking, minimizing the risk of vibration or collision during equipment operation, thereby improving testing accuracy and equipment safety.

[0056] For example, such as Figure 4 and Figure 5 As shown, the detachable end 532 has a through hole 533, and the fixing part 52 has a fixing hole 521 corresponding to the through hole 533. The through hole 533 and the fixing hole 521 are connected by fasteners.

[0057] The through hole 533 and the fixing hole 521 are positioned correspondingly by being coaxially arranged. The diameter of both holes can be set to match the outer diameter of the fastener. For example, the inner diameter of the through hole 533 can be slightly larger than the outer diameter of the fastener to allow for slight positional deviations, while the inner diameter of the fixing hole 521 can form an interference fit with the outer diameter of the fastener. The fastener can be a bolt, screw, or pin, and its length must be sufficient to pass through the through hole 533 and the fixing hole 521 to form an effective lock.

[0058] When the laser device 40 needs to be fixed, the detachable end 532 of the spring arm 53 moves toward the fixing part 52 until the through hole 533 aligns with the fixing hole 521. At this point, the fastener passes through both to form a mechanical connection. In a vibration environment, the interference fit between the fastener and the fixing hole 521 prevents the connection from loosening. When disassembly is required, simply loosening the fastener releases the constraint of the spring arm 53 on the laser device 40. The spring arm 53 then springs outward to form an opening gap, facilitating the quick removal of the laser device 40. This structure, through the synergistic effect of mechanical positioning and rigid locking, effectively avoids the problem of test laser beam path deviation caused by insufficient clamping force while retaining the quick disassembly and assembly function of the spring arm 53.

[0059] The above technical solution solves the problems of inaccurate alignment and insufficient tightening force when connecting the spring arm 53 and the fixing part 52. Specifically, the corresponding design of the through hole 533 and the fixing hole 521 ensures accurate alignment of the spring arm 53 and the fixing part 52 during connection, avoiding installation deviations caused by misalignment. The use of fasteners provides stable clamping force through mechanical locking, enabling the spring arm 53 to firmly press against the laser device 40 in the closed state, preventing loosening due to external vibration or operational impact. In addition, the detachable nature of the fasteners retains the advantage of quick assembly and disassembly of the spring arm 53, ensuring the stability of the laser device 40 installation and facilitating disassembly operations during maintenance.

[0060] For example, such as Figures 1 to 3 As shown, the wafer testing equipment also includes a wafer carrier 60, which is installed at the test position and is used to carry the wafer. The lifting mechanism 20 has a minimum preset position on the lifting trajectory. When the lifting mechanism 20 is at the minimum preset position, a preset anti-collision distance is formed between the laser device 40 and the wafer carrier 60.

[0061] The wafer carrier 60 is fixed at the test position, and its bearing surface height forms a spatial constraint relationship with the movement trajectory of the lifting mechanism 20. The lowest preset position can be achieved through a mechanical limit structure or a position sensor, such as setting a limit block at the bottom of the lifting mechanism 20 or installing a contact sensor at the end of the guide rail. The setting of the preset anti-collision distance needs to be combined with the thickness of the wafer carrier 60, the distance from the bottom of the laser device 40 to the light-emitting end, and the safety margin. The synergistic effect of the wafer carrier 60 and the lifting mechanism 20 is reflected in the following: the fixed installation of the wafer carrier 60 provides a reference for the lower limit position of the laser device 40, while the lowest preset position forcibly terminates the descent of the lifting mechanism 20 through physical or electronic means. Together, they ensure that there is always an isolation space between the laser device 40 and the carrier.

[0062] When the lifting mechanism 20 drives the laser device 40 to descend, its range of motion is limited to above the lowest preset position. Upon reaching this position, the vertical distance between the laser device 40 and the wafer carrier 60 is the preset anti-collision distance. This distance must meet two conditions: first, it must ensure that the laser focus is accurately focused on the wafer surface, for example, by calculating the sum of the focal length of the laser device 40 and the thickness of the carrier; second, it must provide sufficient safety margin to avoid accidental contact caused by the carrier during loading and unloading. The preset anti-collision distance can be set to a safe distance, such as 10mm. This distance ensures that the laser device 40 will not make physical contact with the wafer carrier 60, and also ensures that the laser focus is accurately applied to the wafer surface.

[0063] The above technical solution effectively solves the problem of potential collisions between the laser device 40 and the wafer carrier 60. By setting a minimum preset position on the lifting trajectory of the lifting mechanism 20 and maintaining a preset anti-collision distance between the laser device 40 and the wafer carrier 60 at this position, the descent range of the laser device 40 is effectively limited. This design, combining mechanical limiting and spatial isolation, prevents collisions caused by uncontrolled lifting mechanism 20 or operational errors, thereby avoiding the risk of equipment damage and decreased testing accuracy. Simultaneously, this solution ensures that the laser device 40 can accurately test the wafer within a safe distance, improving the reliability and efficiency of wafer testing.

[0064] For example, the wafer testing equipment further includes a driving device, a control unit, and a position sensor. The driving device and the position sensor are both electrically connected to the control unit. The driving device is used to drive the lifting mechanism 20 to move up and down. The position sensor is installed on the lifting mechanism 20 and is used to detect the current position of the lifting mechanism 20. The control unit is used to control the driving device to stop running when the current position of the lifting mechanism 20 reaches the minimum preset position.

[0065] The drive unit can use a servo motor or a stepper motor as the power source, and its output shaft is mechanically connected to the lifting mechanism 20 via a lead screw or gear set. The position sensor can be a photoelectric encoder or a magnetic scale, and its installation position is configured to maintain synchronous displacement with the moving parts of the lifting mechanism 20. The control unit can integrate a PLC or an embedded controller, whose internal storage module pre-stores the coordinate data of the lowest preset position. When the lifting mechanism 20 moves, the pulse signal generated by the position sensor is transmitted to the control unit in real time via a data line. The control unit compares the real-time position data with a preset threshold, and generates a stop command when the difference is less than a set tolerance.

[0066] During the descent of the lifting mechanism 20, the position sensor continuously collects vertical displacement data and converts it into an electrical signal, which is transmitted to the signal input terminal of the control unit via a cable. The data processing module of the control unit compares the real-time position value with the stored lowest preset position. When the real-time position value is detected to be equal to or exceed the preset value, a power-off command is immediately sent to the drive device. After receiving the stop signal, the drive device brakes its power output shaft, bringing the lifting mechanism 20 to a complete stop. Through electronic real-time position monitoring, the lag error caused by the operator's visual judgment can be avoided, ensuring that the distance between the laser device 40 and the wafer carrier 60 is always maintained within a safe range.

[0067] The above technical solution achieves precise positioning control of the lifting mechanism 20. The closed-loop feedback system overcomes the problems of insufficient precision in mechanical limit structures and human error, ensuring that the lifting mechanism 20 can accurately stop at the preset anti-collision position. This electronic position control method significantly improves positioning accuracy, effectively preventing accidental collisions between the laser device 40 and the wafer carrier 60, protecting critical equipment components, reducing downtime caused by collisions, and improving equipment reliability and production efficiency. Simultaneously, precise position control also ensures a stable distance between the laser device 40 and the wafer during testing, contributing to improved accuracy and consistency of test results.

[0068] For example, the support platform 10 is provided with a limiting structure, which is used to limit the lifting mechanism 20 when the lifting mechanism 20 reaches the minimum preset setting, so as to restrict the lifting mechanism 20 from continuing to descend.

[0069] The contact surface between the limiting structure and the lifting mechanism 20 forms a rigid blocking interface. The lifting mechanism 20 is provided with a groove or boss that matches the shape of the limiting structure. When the lifting mechanism 20 descends to the lowest preset position, the sidewall of the groove makes surface contact with the limiting structure, thereby generating resistance to counteract the residual driving force of the drive device.

[0070] When the lifting mechanism 20 is controlled to descend to the lowest preset position, its bottom mechanical components make physical contact with the limiting structure of the support platform 10. At this time, the limiting structure bears the entire downward pressure of the lifting mechanism 20 through the rigid support surface. Even if the drive device continues to operate due to signal delay, its power transmission path is forcibly interrupted by mechanical obstruction. This mechanical limiting mechanism operates independently of the electronic control system and can still effectively prevent collisions in the event of sensor failure or control logic error, while avoiding equipment response delays caused by repeated electronic corrections.

[0071] The above technical solution effectively solves the technical defect of equipment damage caused by overshoot of the lifting mechanism 20 when the electrical control system fails. The mechanical limit structure forms a final protective barrier through physical interference. Even in the event of sensor anomaly detection or control signal delay, the rigid blocking of the metal contact surface can still forcibly terminate the lifting movement, completely eliminating the possibility of collision between the laser device 40 and the wafer carrier 60. This structure does not rely on the response speed of electronic components or the execution logic of the control program, and can maintain reliable protective performance in unexpected situations, significantly improving the safety and stability of equipment operation.

[0072] The present invention also proposes a control method for a wafer testing device, for controlling the wafer testing device as described above, the control method comprising the following steps:

[0073] S100, Obtain test instructions;

[0074] S200. According to the test command, control the lifting mechanism 20 to descend to the first preset position;

[0075] S300: Confirm that the lifting mechanism 20 is in the first preset position, and control the camera device 30 to operate;

[0076] S400, control the lifting mechanism 20 to descend from the first preset position to the second preset position, wherein the height difference between the first preset position and the second preset position is equal to the height difference between the laser focus emitted by the laser device 40 and the visual focusing surface 31 of the camera device 30;

[0077] S500: Confirm that the lifting mechanism 20 is in the second preset position, and control the laser device 40 to operate.

[0078] Test commands can be automatically generated via external trigger signals or preset programs, such as start commands input from the operating interface or control signals linked with a host computer. The first preset position is set as the initial height at which the camera device 30 can achieve focusing; its specific value can be determined through pre-calibration. The height difference between the second preset position and the first preset position compensates for the spatial difference between the laser focus and the visual focusing surface 31. For example, when the visual focusing surface 31 is 25 mm lower than the laser focus, the lifting mechanism 20 needs to descend an additional 25 mm to achieve accurate focus positioning. The position confirmation process can be achieved using photoelectric sensors or encoders installed on the lifting mechanism 20. When the detection signal matches a preset threshold, the next step is executed.

[0079] Upon receiving the test command, the lifting mechanism 20 is first driven to a first preset height. During this stage, the camera device 30 is activated to acquire images of the wafer surface, completing focusing and positioning operations. Once visual positioning is complete, the lifting mechanism 20 continues to descend based on a preset height difference h, which is precisely matched to the distance between the laser focus and the visual focusing surface 31. For example, in a configuration where the visual focusing surface 31 is 25 mm lower than the laser focus, the lifting mechanism 20 needs to descend another 25 mm from the first preset position. During this process, the position sensor monitors the lifting stroke in real time, and when a second preset position is detected, the laser device 40 is triggered. Through a phased descent and height difference compensation mechanism, the integrity of visual positioning is ensured, while the risk of laser focus offset is eliminated.

[0080] The above technical solution effectively eliminates the risk of motion interference between visual positioning and laser testing, and ensures that the optical components operate at their optimal working distances through a phased height adjustment mechanism. Specifically, after the vision system is precisely calibrated at the first preset position, a compensatory displacement is performed based on the preset height difference, allowing the laser focus to accurately project onto the visually confirmed coordinates of the wafer surface at the second position. This control logic, which links timing control with spatial positioning, significantly improves the reliability of equipment operation and the consistency of test data.

[0081] For example, after confirming that the lifting mechanism 20 is in the second preset position and controlling the operation of the laser device 40, the method further includes:

[0082] S600, control the lifting mechanism 20 to descend from the second preset position to the third preset position, wherein the height difference between the second preset position and the third preset position is less than or equal to the thickness of the wafer, so that the laser focus emitted by the laser device 40 falls on the lower surface of the wafer.

[0083] S700: Confirm that the lifting mechanism 20 is in the third preset position, and control the laser device 40 to operate.

[0084] The height difference between the second and third preset positions is limited to the upper limit of the wafer thickness. Constrained by this height difference, when the laser device 40 is focused at the third preset position, it will inevitably penetrate the upper surface of the wafer and reach the lower surface. When the laser device 40 is operated again at the third preset position, the reflected light signal generated by the laser device 40 at the lower surface is combined with the data from the upper surface to calculate the overall wafer thickness and warpage. Furthermore, during the phased descent of the lifting mechanism 20, the position sensor continuously monitors the current position. When the third preset position is reached, the control unit immediately locks the position of the lifting mechanism 20 to ensure the stability of the laser beam path.

[0085] After the camera device 30 completes the laser test at the second preset position, the lifting mechanism 20 is controlled to descend from the second preset position to the third preset position in a fine-tuning step manner. The movement distance of this fine-tuning step is preset to an integer multiple or fraction of the wafer thickness. For example, the descent step size can be set to 1 / 10 of the wafer thickness to gradually approach the lower surface. When the position sensor detects that the lifting mechanism 20 has reached the third preset position, the laser device 40 is triggered to operate. At this time, the focus of the laser device 40 is exactly located on the lower surface of the wafer, thereby acquiring the reflected signal from the lower surface. Since the height difference between the second and third positions does not exceed the wafer thickness, the laser device 40 does not need to readjust the wafer position or the angle of the laser device 40 when the focus is on the lower surface for testing. Alignment can be directly performed using the wafer coordinate data acquired by the camera device 30 at the second position.

[0086] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A wafer testing device, characterized in that, include: A support platform, wherein the support platform is provided with test positions for placing wafers; A lifting mechanism is mounted on the support platform in a height-reducible manner; A camera device is mounted on the lifting mechanism, with the camera end of the camera device facing the test position, and the camera device is used to acquire image information of the wafer placed on the test position; A laser device is mounted on the lifting mechanism, with the light-emitting end of the laser device facing the test position, and the laser device is used to emit a test laser toward the wafer placed on the test position; The laser emitted by the laser device has a focal point higher than the visual focal plane of the camera device.

2. The wafer testing equipment as described in claim 1, characterized in that, The height difference between the laser focal point emitted by the laser device and the visual focal plane of the camera device is set to 20mm to 30mm.

3. The wafer testing equipment as described in claim 1, characterized in that, The laser device is mounted at an adjustable height on the lifting mechanism.

4. The wafer testing equipment as described in claim 3, characterized in that, The wafer testing equipment also includes a mounting base installed on the lifting mechanism. The mounting base has a connecting boss, which includes a fixed part and a spring arm part. The spring arm part has a fixed end and a detachable end. The fixed end is connected to one end of the fixed part. The middle part of the spring arm part and the middle part of the fixed part form a mounting hole. The detachable end is detachably connected to the other end of the fixed part. The laser device is installed in the mounting hole. When the detachable end is connected to the fixed part, the spring arm part presses the laser device tightly against the mounting hole. When the detachable end is separated from the fixed part, the spring arm part releases the laser device.

5. The wafer testing equipment as described in claim 4, characterized in that, The detachable end has a through hole, and the fixing part has a fixing hole corresponding to the through hole. The through hole and the fixing hole are connected by fasteners.

6. The wafer testing equipment as described in claim 1, characterized in that, The wafer testing equipment also includes a wafer carrier, which is installed at the test position and is used to carry the wafer. The lifting mechanism has a minimum preset position on the lifting trajectory. When the lifting mechanism is at the minimum preset position, a preset anti-collision distance is formed between the laser device and the wafer carrier.

7. The wafer testing equipment as described in claim 6, characterized in that, The wafer testing equipment also includes a drive device, a control unit, and a position sensor. The drive device and the position sensor are both electrically connected to the control unit. The drive device is used to drive the lifting mechanism to move up and down. The position sensor is installed on the lifting mechanism and is used to detect the current position of the lifting mechanism. The control unit is used to control the drive device to stop running when the current position of the lifting mechanism reaches the minimum preset position.

8. The wafer testing equipment as described in claim 6, characterized in that, The support platform is provided with a limiting structure, which is used to cooperate with the lifting mechanism to limit the lifting mechanism from continuing to descend when the lifting mechanism reaches the minimum preset setting.

9. A control method for a wafer testing device, characterized in that, The wafer testing equipment includes a carrier platform, a lifting mechanism, a camera device, and a laser device; the carrier platform is provided with a test position for placing wafers; the lifting mechanism is movably mounted on the carrier platform; the camera device is mounted on the lifting mechanism, with the camera end of the camera device facing the test position, and the camera device is used to acquire image information of the wafer placed on the test position; The laser device is mounted on the lifting mechanism, with its light-emitting end facing the test position. The laser device is used to emit a test laser towards the wafer placed on the test position; wherein the focal point of the laser emitted by the laser device is higher than the visual focal plane of the camera device. The control method for the wafer testing equipment includes the following steps: Get test instructions; According to the test command, control the lifting mechanism to descend to the first preset position; Confirm that the lifting mechanism is in the first preset position, and control the camera device to operate; The lifting mechanism is controlled to descend from a first preset position to a second preset position, wherein the height difference between the first preset position and the second preset position is equal to the height difference between the laser focal point emitted by the laser device and the visual focal plane of the camera device; Confirm that the lifting mechanism is in the second preset position, and control the operation of the laser device.

10. The control method for the wafer testing equipment as described in claim 9, characterized in that, After confirming that the lifting mechanism is in the second preset position and controlling the operation of the laser device, the method further includes: The lifting mechanism is controlled to descend from a second preset position to a third preset position, wherein the height difference between the second preset position and the third preset position is less than or equal to the thickness of the wafer, so that the laser focus emitted by the laser device falls on the lower surface of the wafer. Confirm that the lifting mechanism is in the third preset position, and control the operation of the laser device.

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