Integrated circuit package device temperature drift compensation method and system based on visual calibration

Abstract

The present application relates to the technical field of integrated circuit packaging equipment, solves the problem that temperature change causes the drift of the motion platform pulse equivalent and the visual coordinate conversion relationship, and affects the positioning accuracy, and provides an integrated circuit packaging equipment temperature drift compensation method and system based on visual calibration. The method obtains the current temperature of the equipment and determines the temperature deviation, determines the current pulse equivalent according to the preset pulse equivalent temperature drift relationship; controls the motion platform to move in different directions and collects the calibration image, determines the visual equivalent and the coordinate deflection angle in different directions according to the pixel displacement of the calibration feature; according to the visual calibration parameters and the current pulse equivalent, the target pixel position of the integrated circuit to be processed is converted into the target motion pulse number. The present application can jointly compensate the temperature drift of the motion platform and the visual system, and improve the positioning accuracy and running stability of the equipment under different temperature conditions.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit packaging equipment technology, and in particular to a method and system for temperature drift compensation of integrated circuit packaging equipment based on visual calibration. Background Technology

[0002] When performing operations such as chip picking, handling, mounting, sorting, and inspection, integrated circuit packaging equipment typically acquires the image position of the integrated circuit to be processed through an imaging module. Based on the coordinate transformation relationship between the image coordinate system and the equipment coordinate system, it controls the motion platform to move the integrated circuit to the target position. The vision calibration parameters and the displacement control accuracy of the motion platform directly affect the positioning accuracy and operational consistency of the integrated circuit packaging equipment.

[0003] During continuous operation, the motion drive unit, lead screw, guide rail, motion platform, imaging module, and their mounting structure of integrated circuit packaging equipment may experience thermal expansion or deformation due to equipment heating or changes in ambient temperature. This causes drift in the actual displacement corresponding to a unit pulse of the motion platform and the coordinate transformation relationship between the image coordinate system and the equipment coordinate system. If the pulse equivalent and visual calibration parameters determined at the reference temperature are still used for motion control, the actual movement position of the integrated circuit to be processed may easily deviate from the target position.

[0004] In the prior art, for example, Chinese invention patent application CN113763485A discloses a method for obtaining temperature drift coefficient, an electronic device, a storage medium, and an image correction method. This method involves taking pictures of the same calibration board with a target camera at different temperatures, extracting key points from the images of the calibration board at different temperatures, matching the key points at different temperatures to determine the displacement function of corresponding points with temperature, and obtaining the temperature drift coefficient of the target camera based on this function. During image correction, the corresponding temperature drift coefficient is selected based on the ambient temperature at the time the image was taken, and the pixel coordinates of the target image are corrected.

[0005] However, the aforementioned existing technologies mainly address camera imaging coordinate deviations caused by temperature changes, without incorporating the temperature-dependent changes in the pulse equivalent of the motion platform into the visual calibration process. When the actual displacement corresponding to a unit pulse changes due to temperature variations in the motion platform's transmission mechanism, even after correcting the image pixel coordinates, converting the pixel position into the number of motion pulses based on a fixed pulse equivalent may still result in motion positioning errors, making it difficult to meet the high-precision positioning requirements of integrated circuit packaging equipment. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a method and system for temperature drift compensation of integrated circuit packaging equipment based on visual calibration, in order to solve the problem that the prior art only corrects the temperature drift of pixel coordinates of camera images, without considering the motion positioning error caused by the change of pulse equivalent of motion platform with temperature.

[0007] In a first aspect, embodiments of the present invention provide a method for temperature drift compensation of integrated circuit packaging equipment based on visual calibration, applied to integrated circuit packaging equipment, wherein the integrated circuit packaging equipment includes an imaging module for acquiring images and a temperature acquisition module for acquiring temperature information of the integrated circuit packaging equipment, and the method includes: The current temperature of the integrated circuit packaging equipment is obtained, and the temperature deviation is determined based on the current temperature and the reference temperature. Based on the temperature deviation and the preset pulse equivalent temperature drift relationship, the current pulse equivalent of the motion platform of the integrated circuit packaging equipment at the current temperature is determined. The preset pulse equivalent temperature drift relationship is a data relationship established in advance based on the temperature deviation and corresponding pulse equivalent at multiple calibration temperatures, used to characterize the correspondence between temperature deviation and pulse equivalent. Based on the current pulse equivalent, the motion platform is controlled to move the calibration plate with calibration features along different directions of the device coordinate system for a preset number of pulses, and the imaging module is used to acquire calibration images of the calibration plate before and after the movement. Based on the calibration image, determine the pixel displacement of the calibration feature in different directions; Based on the current pulse equivalent, the preset pulse number, and the pixel displacement, visual calibration parameters adapted to the current temperature are determined, wherein the visual calibration parameters are used to characterize the coordinate mapping relationship between the image coordinate system and the device coordinate system; Based on the visual calibration parameters and the current pulse equivalent, the target pixel position of the integrated circuit to be processed is converted by temperature drift compensation to obtain the target motion pulse number used to control the motion of the motion platform.

[0008] Preferably, determining the current pulse equivalent of the motion platform at the current temperature based on the temperature deviation and the preset pulse equivalent temperature drift relationship includes: Based on the preset temperature set and the reference temperature, a preset pulse equivalent temperature drift relationship is constructed. The preset temperature set includes several different temperature data within the preset operating temperature range of the integrated circuit packaging equipment. Based on the position of the temperature deviation in the preset pulse equivalent temperature drift relationship, the target temperature range corresponding to the current temperature is determined; Obtain the first calibration temperature deviation, the second calibration temperature deviation, the first calibration pulse equivalent, and the second calibration pulse equivalent corresponding to the two endpoints of the target temperature range, respectively; Based on the temperature deviation, the first calibration temperature deviation, and the second calibration temperature deviation, determine the temperature position coefficient of the current temperature within the target temperature range; Based on the first calibrated pulse equivalent, the second calibrated pulse equivalent, and the temperature position coefficient, the current pulse equivalent of the motion platform at the current temperature is determined.

[0009] Preferably, constructing the preset pulse equivalent temperature drift relationship based on the preset temperature set and the reference temperature includes: Based on the temperature data in the preset temperature set and the reference temperature, determine the calibration temperature deviation corresponding to each temperature data. The temperature change sequence of the integrated circuit packaging equipment under each of the temperature data is obtained, and when the temperature change rate of the temperature change sequence meets the preset thermal stability condition, the calibration temperature state corresponding to each of the temperature data is determined. Under each of the specified calibration temperature conditions, the motion platform is controlled to sequentially execute forward calibration pulse displacement and reverse calibration pulse displacement along the preset calibration direction, and the forward actual displacement and reverse actual displacement corresponding to the forward calibration pulse displacement and the reverse calibration pulse displacement are obtained respectively. Based on the forward calibration pulse displacement, the reverse calibration pulse displacement, the forward actual displacement, and the reverse actual displacement, determine the forward pulse equivalent, reverse pulse equivalent, and directional hysteresis parameter corresponding to each calibration temperature state; Based on the directional hysteresis parameter corresponding to each calibration temperature state and the dispersion of the pulse equivalent obtained from multiple repeated calibrations, the positive pulse equivalent and the negative pulse equivalent are effectively screened and fused to obtain the target calibration pulse equivalent corresponding to each calibration temperature deviation. Based on the changing trend of the target calibration pulse equivalent corresponding to each calibration temperature deviation, the preset working temperature range is divided into several different temperature intervals; The preset pulse equivalent temperature drift relationship is obtained by fitting the calibration temperature deviation and the target calibration pulse equivalent within each of the temperature ranges.

[0010] Preferably, determining the target temperature range corresponding to the current temperature based on the corresponding position of the temperature deviation in the preset pulse equivalent temperature drift relationship includes: Obtain the temperature data of the integrated circuit packaging device prior to the current sampling time to obtain the current temperature change sequence; The current temperature change direction and current temperature change rate are determined based on the current temperature change sequence, wherein the current temperature change direction includes a heating direction and a cooling direction. Based on the current temperature change direction, select the corresponding target temperature drift relationship branch from the preset pulse equivalent temperature drift relationship, wherein the preset pulse equivalent temperature drift relationship includes a temperature rise temperature drift relationship branch and a temperature fall temperature drift relationship branch; Based on the current rate of temperature change, determine the temperature range matching range corresponding to the temperature deviation; The temperature range matching range is matched with multiple preset temperature ranges included in the target temperature drift relationship branch to obtain at least one candidate temperature range; The target temperature range is determined from at least one of the candidate temperature ranges based on the distance between the temperature deviation and the endpoints of each candidate temperature range.

[0011] Preferably, the calibration plate includes a low thermal expansion substrate and a plurality of calibration features disposed on the low thermal expansion substrate. The plurality of calibration features are arranged at a preset interval. The low thermal expansion substrate is made of at least one of microcrystalline glass, ceramic, and quartz glass. The calibration features include at least one of circular features, square features, cross-shaped features, and checkerboard corner points. Based on the current pulse equivalent, controlling the motion platform to move the calibration plate with calibration features disposed thereon along different directions of the device coordinate system for a preset number of pulses, and acquiring calibration images of the calibration plate before and after the movement through the imaging module, includes: Based on the current pulse equivalent and the preset calibration displacement range, determine the first calibration pulse number and the second calibration pulse number corresponding to the first and second directions of the motion platform along the device coordinate system, respectively; Control the motion platform to move to the initial calibration position where the calibration feature is within the preset calibration field of view of the imaging module; The motion platform is controlled to move along the first direction by the first number of calibration pulses, and the first calibration image group before and after the movement is acquired respectively; The motion platform is controlled to move along the second direction by the second calibration pulse number, and the second calibration image group before and after the movement is acquired respectively; By associating the first calibration image group, the second calibration image group, and the corresponding calibration pulse number, visual calibration data corresponding to the current temperature is obtained.

[0012] Preferably, determining the pixel displacement of the calibration feature in different directions based on the calibration image includes: Target image regions containing the calibration features are determined from the first calibration image group and the second calibration image group, respectively; Feature contours are extracted from each of the target image regions to obtain the feature contours of the calibration features before and after the movement. The sub-pixel coordinates of the calibrated features before and after movement are determined based on the feature contours described above; The first pixel displacement is determined based on the sub-pixel coordinates of the calibration feature before and after moving along the first direction. The second pixel displacement is determined based on the sub-pixel coordinates of the calibration feature before and after moving along the second direction; Based on the dispersion of the first and second pixel displacements obtained from repeated visual calibration, abnormal pixel displacements are removed, and the first and second target pixel displacements are determined based on the remaining first and second pixel displacements, respectively.

[0013] Preferably, determining the visual calibration parameters adapted to the current temperature based on the current pulse equivalent, the preset pulse number, and the pixel displacement includes: Based on the first calibration pulse count and the current pulse equivalent, the first calibration actual displacement of the motion platform along the first direction is determined; Based on the second calibration pulse count and the current pulse equivalent, determine the second calibration actual displacement of the motion platform along the second direction; The first directional visual equivalent is determined based on the correspondence between the first calibrated actual displacement and the first target pixel displacement; The second directional visual equivalent is determined based on the correspondence between the second calibrated actual displacement and the second target pixel displacement; Based on the pixel displacement components of the first target pixel displacement and the second target pixel displacement on the two coordinate axes of the image coordinate system, the first projection direction angle and the second projection direction angle of the first direction and the second direction in the image coordinate system are determined respectively. The first direction angle difference and the second direction angle difference are determined based on the angle differences between the first projection direction angle and the second projection direction angle and the preset direction angle of the corresponding direction in the device coordinate system. Based on the first directional angle difference and the second directional angle difference, determine the coordinate deflection angle between the image coordinate system and the device coordinate system; Based on the visual equivalent in the first direction, the visual equivalent in the second direction, and the coordinate deflection angle, visual calibration parameters adapted to the current temperature are obtained.

[0014] Preferably, the step of performing temperature drift compensation conversion on the target pixel position of the integrated circuit to be processed based on the visual calibration parameters and the current pulse equivalent to obtain the target motion pulse number for controlling the motion platform includes: Obtain the current pixel coordinates of the integrated circuit to be processed in the detected image and the target pixel coordinates corresponding to the integrated circuit to be processed; Based on the current pixel coordinates and the target pixel coordinates, determine the target pixel displacement of the integrated circuit to be processed in the image coordinate system; Based on the coordinate deflection angle, the target pixel displacement is subjected to coordinate rotation transformation to obtain the first direction pixel displacement and the second direction pixel displacement corresponding to the target pixel displacement in the first direction and the second direction in the device coordinate system, respectively. Based on the visual equivalent in the first direction and the pixel displacement in the first direction, the physical displacement of the motion platform along the first direction corresponding to the first target is determined; Based on the visual equivalent in the second direction and the pixel displacement in the second direction, the physical displacement of the motion platform along the second direction corresponding to the second target is determined; The number of motion pulses of the first target is determined based on the physical displacement of the first target and the current pulse equivalent corresponding to the first direction; The number of motion pulses of the second target is determined based on the physical displacement of the second target and the current pulse equivalent corresponding to the second direction; Based on the first target motion pulse count and the second target motion pulse count, a temperature drift compensation motion control command is generated to control the motion platform to move the integrated circuit to be processed to the target position.

[0015] Preferably, after controlling the motion platform to move the integrated circuit to be processed to the target position, the method further includes: The imaging module acquires a compensation verification image of the integrated circuit to be processed after it has been moved. Extract the compensated pixel coordinates of the integrated circuit to be processed from the compensated verification image; Based on the compensated pixel coordinates and the target pixel coordinates, determine the compensation residual vector in the image coordinate system; Based on the coordinate deflection angle, the compensation residual vector is converted into a first-direction compensation residual and a second-direction compensation residual in the device coordinate system; The first direction compensation residual and the second direction compensation residual are compared with the corresponding preset direction residual thresholds, respectively; When both the first-direction compensation residual and the second-direction compensation residual are less than or equal to the corresponding preset direction residual threshold, it is determined that the current pulse equivalent and the visual calibration parameter have passed the compensation validity verification. When at least one of the first direction compensation residual and the second direction compensation residual is greater than the corresponding preset direction residual threshold, the calibration parameter to be updated is determined according to the target direction that exceeds the preset direction residual threshold; The motion platform is controlled to re-perform visual calibration along the target direction, and the visual equivalent and current pulse equivalent corresponding to the target direction are updated based on the pixel displacement obtained from the re-perform visual calibration. Based on the updated visual equivalent and the current pulse equivalent, the number of target motion pulses corresponding to the target direction is re-determined, and the motion platform is controlled to perform temperature drift compensation motion again.

[0016] Secondly, embodiments of the present invention provide a temperature drift compensation system for integrated circuit packaging equipment based on visual calibration, characterized in that the system includes a motion platform, a motion driving unit, an imaging module, a temperature acquisition module, a calibration board, and a processor; The motion platform is used to carry the integrated circuit to be processed and / or the calibration board; the motion driving unit is connected to the motion platform for driving the motion platform to move in different directions of the device coordinate system according to motion control commands, and outputting motion pulse data corresponding to the motion platform; the calibration board is provided with calibration features for visual calibration; the imaging module is positioned towards the motion platform and is used to acquire calibration images of the calibration features before and after moving with the motion platform, as well as to acquire detection images of the integrated circuit to be processed; the temperature acquisition module is used to acquire the current temperature of the integrated circuit packaging equipment; the processor is communicatively connected to the motion driving unit, the imaging module and the temperature acquisition module respectively to implement the method of the first aspect.

[0017] In summary, the beneficial effects of the present invention are as follows: The integrated circuit packaging equipment temperature drift compensation method and system based on visual calibration provided in this invention obtains the current temperature of the integrated circuit packaging equipment, determines the temperature deviation of the current temperature relative to the reference temperature, and determines the current pulse equivalent of the motion platform at the current temperature based on the temperature deviation and the preset pulse equivalent temperature drift relationship. This enables the displacement control reference of the motion platform to be adapted to the current temperature state of the equipment, reducing the motion positioning error caused by the inconsistency between the reference pulse equivalent and the actual displacement per unit pulse when the lead screw, guide rail, motion platform and related transmission structure undergo thermal expansion or thermal deformation due to temperature changes.

[0018] Secondly, this invention controls the motion platform to move a preset number of pulses along different directions of the device coordinate system based on the current pulse equivalent, and determines the corresponding pixel displacement based on the calibration images before and after the movement of the calibration features. This, in turn, determines the visual equivalent in different directions adapted to the current temperature, as well as the coordinate deflection angle between the image coordinate system and the device coordinate system. Therefore, the visual calibration parameters no longer use historical calibration results at a fixed reference temperature, but instead reflect the actual positional relationship of the imaging module, motion platform, and its mounting structure under the current temperature conditions, reducing imaging magnification drift, coordinate direction offset, and visual motion mapping errors caused by temperature changes.

[0019] Finally, based on visual calibration parameters adapted to the current temperature and the current pulse equivalent, this invention performs temperature drift compensation transformation on the target pixel position of the integrated circuit to be processed, obtaining the target motion pulse number used to control the motion platform. This ensures that the conversion process from image position to device motion control quantity simultaneously considers the temperature drift of the visual coordinate transformation relationship and the temperature drift of the motion platform displacement reference. Compared to methods that only perform temperature correction on image pixel coordinates, this invention can achieve joint temperature drift compensation of the vision system and the motion system. This is beneficial for improving the chip picking, handling, placement, sorting, and detection positioning accuracy of integrated circuit packaging equipment under continuous operation and different temperature environments, thereby enhancing the consistency of packaging operations and the stability of equipment operation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of the present invention.

[0021] Figure 1 This is a schematic flowchart of the temperature drift compensation method for integrated circuit packaging equipment based on visual calibration according to an embodiment of the present invention.

[0022] Figure 2 This is another schematic diagram of the temperature drift compensation method for integrated circuit packaging equipment based on visual calibration according to an embodiment of the present invention.

[0023] Figure 3 This is another schematic diagram of the temperature drift compensation method for integrated circuit packaging equipment based on visual calibration according to an embodiment of the present invention. Detailed Implementation

[0024] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0025] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0026] Example 1 This invention provides a method for temperature drift compensation of integrated circuit packaging equipment based on visual calibration, which is applied to integrated circuit packaging equipment. The integrated circuit packaging equipment includes a motion platform, a motion driving unit for driving the motion platform, an imaging module for acquiring images of the motion platform, and a temperature acquisition module for acquiring temperature information of the integrated circuit packaging equipment.

[0027] The method includes: S1. Obtain the current temperature of the integrated circuit packaging equipment, and determine the temperature deviation based on the current temperature and the reference temperature; The current temperature refers to the temperature data that characterizes the current thermal state of the motion platform, motion drive unit, imaging module, and their mounting structure when the integrated circuit packaging equipment performs this temperature drift compensation. In practice, temperature data can be collected by temperature sensors located on the motion platform, motion drive unit, imaging module mounting base, or inside the equipment. Alternatively, temperature data collected from multiple temperature sensors can be averaged or weighted, and the result can be used as the current temperature. The reference temperature is the temperature corresponding to the initial calibration of the equipment, such as the factory calibration temperature or the standard operating temperature when the equipment is in a thermally stable state. The difference between the current temperature and the reference temperature yields the temperature deviation, which characterizes the degree of change in the current thermal state of the equipment relative to the reference calibration state. This step converts the equipment temperature change into a quantitative parameter that can participate in subsequent pulse equivalent correction, providing a basis for determining the actual displacement reference of the motion platform at the current temperature.

[0028] S2. Based on the temperature deviation and the preset pulse equivalent temperature drift relationship, determine the current pulse equivalent of the motion platform of the integrated circuit packaging equipment at the current temperature, wherein the preset pulse equivalent temperature drift relationship is a data relationship established in advance based on the temperature deviation and corresponding pulse equivalent at multiple calibration temperatures, used to characterize the correspondence between temperature deviation and pulse equivalent; Pulse equivalent refers to the actual physical displacement generated when a motion platform receives a unit motion pulse. Since the motion platform and its transmission structure may undergo thermal expansion or deformation due to temperature changes, the pulse equivalent at a reference temperature may not accurately reflect the actual motion response at the current temperature. Therefore, temperature deviations relative to the reference temperature are obtained at multiple calibration temperatures beforehand, and the pulse equivalent corresponding to each temperature deviation is measured to establish a preset pulse equivalent temperature drift relationship. In specific implementation, the temperature deviations determined in step S1 are matched with the preset pulse equivalent temperature drift relationship. The current pulse equivalent of the motion platform at the current temperature is obtained through relational calculations, table lookups, or interval interpolation, thus ensuring that the displacement reference used for subsequent visual calibration and motion control is adapted to the current thermal state of the equipment.

[0029] S3. Based on the current pulse equivalent, control the motion platform to move the calibration plate with calibration features along different directions of the device coordinate system for a preset number of pulses, and obtain calibration images of the calibration plate before and after the movement through the imaging module; A calibration plate is mounted on a motion platform and moves synchronously with it. Calibration features on the calibration plate provide a identifiable visual position reference for the imaging module. Specifically, based on the current pulse equivalent and the calibration field of view of the imaging module, a preset number of pulses is determined for each direction the motion platform moves. This ensures that the calibration features remain within the effective field of view of the imaging module before and after movement, and that image position changes meet calibration accuracy requirements. Subsequently, the motion platform is controlled to move the calibration plate along a first direction and a second direction of the device coordinate system, and the imaging module acquires calibration images before and after the plate's movement. The first and second directions can be, for example, the X and Y directions of the device coordinate system, thereby obtaining corresponding data between the pulse motion of the motion platform and the changes in the calibration feature images at the current temperature.

[0030] S4. Based on the calibration image, determine the pixel displacement of the calibration feature in different directions; The calibration features can be circular, square, cross-shaped, checkerboard corner points, or other graphic features that can be stably recognized by the imaging module. In specific implementations, image regions containing the calibration features are located from the calibration images before and after the motion platform moves in different directions. These image regions are then subjected to grayscale processing, edge detection, contour extraction, or feature matching to determine the pixel coordinates of the calibration features before and after movement. Furthermore, the sub-pixel coordinates of the calibration features can be obtained through grayscale centroid, contour fitting, or corner point fitting, and the pixel displacement corresponding to each direction is determined based on the difference in sub-pixel coordinates before and after movement. The pixel displacement can include the pixel displacement components of the calibration features on the two coordinate axes of the image coordinate system, characterizing the image position changes caused by the motion platform moving in different directions of the device coordinate system.

[0031] S5. Based on the current pulse equivalent, the preset pulse number, and the pixel displacement, determine visual calibration parameters that are compatible with the current temperature, wherein the visual calibration parameters are used to characterize the coordinate mapping relationship between the image coordinate system and the device coordinate system; Based on the current pulse equivalent and the preset number of pulses for the motion platform to move in different directions, the actual calibration displacement of the motion platform in the corresponding direction can be determined. Then, based on the relationship between each actual calibration displacement and the corresponding pixel displacement, a coordinate mapping relationship between the image coordinate system and the device coordinate system is established, resulting in visual calibration parameters adapted to the current temperature. In one embodiment, the visual calibration parameters may include visual equivalents in different directions and coordinate deflection angles between the image coordinate system and the device coordinate system. The visual equivalent characterizes the actual physical displacement corresponding to a unit pixel displacement, and the coordinate deflection angle characterizes the directional deviation between the two coordinate systems. In another embodiment, a coordinate transformation matrix can be determined based on the actual calibration displacement vectors and pixel displacement vectors in different directions, and this coordinate transformation matrix can be used as the visual calibration parameters. Therefore, the determined visual calibration parameters can reflect the actual coordinate mapping relationship between the imaging module and the motion platform under the current thermal state of the device.

[0032] S6. Based on the visual calibration parameters and the current pulse equivalent, perform temperature drift compensation conversion on the target pixel position of the integrated circuit to be processed to obtain the target motion pulse number used to control the motion platform. The target pixel position of the integrated circuit to be processed can be determined based on the detection image acquired by the imaging module. Specifically, it can include the current pixel position of the integrated circuit to be processed and the target pixel position it should reach when completing the picking, mounting, sorting, or detection operations. Based on the difference between the current pixel position and the target pixel position, the target pixel displacement of the integrated circuit to be processed in the image coordinate system can be obtained. Subsequently, the target pixel displacement is transformed into a coordinate direction based on the coordinate deflection angle determined in step S5, decomposing it into pixel displacements in different directions of the device coordinate system; then, based on the visual equivalent of the corresponding direction, the pixel displacements in different directions are converted into the target physical displacement that the motion platform should produce; finally, based on the current pulse equivalent determined in step S2, the target physical displacement is converted into the target motion pulse number that the motion drive unit should output. The target motion pulse number obtained in this way simultaneously considers the change in the actual displacement per unit pulse of the motion platform at the current temperature, as well as the change in the visual coordinate transformation relationship between the imaging module and the motion platform, which can achieve joint compensation for the temperature drift of the motion system and the temperature drift of the vision system, thereby improving the positioning, handling, mounting, sorting, or detection accuracy of the integrated circuit to be processed.

[0033] Preferably, step S2 includes: S21. Construct a preset pulse equivalent temperature drift relationship based on the preset temperature set and the reference temperature; The preset temperature set includes multiple temperature data points within the preset operating temperature range of the integrated circuit packaging equipment. In practice, a reference temperature is used as the reference for temperature changes. The pulse equivalent of the motion platform at different temperature states is acquired, and a correspondence between temperature deviation and pulse equivalent is established to obtain the preset pulse equivalent temperature drift relationship. This relationship reflects the impact of temperature changes on the actual displacement per unit pulse of the motion platform.

[0034] S22. Determine the target temperature range corresponding to the current temperature based on the corresponding position of the temperature deviation in the preset pulse equivalent temperature drift relationship; The temperature deviation corresponding to the current temperature is compared with multiple calibration temperature deviations in a preset pulse equivalent temperature drift relationship to determine the position of the current temperature within that relationship. The temperature range containing these deviations is then defined as the target temperature range. This step allows for the selection of calibration data adjacent to the current temperature from the preset pulse equivalent temperature drift relationship.

[0035] S23. Obtain the first calibration temperature deviation, the second calibration temperature deviation, the first calibration pulse equivalent, and the second calibration pulse equivalent corresponding to the two endpoints of the target temperature range, respectively. Based on the target temperature range, the calibration temperature deviation and calibration pulse equivalent corresponding to the two endpoints of the target temperature range are read from the preset pulse equivalent temperature drift relationship. The obtained endpoint data are used to define the range of pulse equivalent values ​​corresponding to the current temperature and to provide basic data for subsequently determining the current pulse equivalent.

[0036] S24. Determine the temperature position coefficient of the current temperature within the target temperature range based on the temperature deviation, the first calibration temperature deviation, and the second calibration temperature deviation; Based on the position of the current temperature deviation relative to the two endpoints of the target temperature range, the relative position of the current temperature within the target temperature range is determined, and this relative position is characterized as a temperature position coefficient. The temperature position coefficient reflects the degree to which the current temperature approaches the two endpoints of the target temperature range.

[0037] S25. Determine the current pulse equivalent of the motion platform at the current temperature based on the first calibrated pulse equivalent, the second calibrated pulse equivalent, and the temperature position coefficient; Based on the temperature position coefficient, the calibration pulse equivalents corresponding to the endpoints of the two intervals of the target temperature range are processed to obtain the current pulse equivalent at the current temperature. This allows the current pulse equivalent to be adaptively adjusted according to the equipment temperature state, and provides a displacement reference adapted to the current temperature for subsequent visual calibration and motion control.

[0038] Preferably, step S21 includes: S211. Determine the calibration temperature deviation corresponding to each temperature data according to the temperature data in the preset temperature set and the reference temperature. The reference temperature is the temperature used for initial calibration or standard precision calibration of integrated circuit packaging equipment. By comparing each temperature data point in the preset temperature set with the reference temperature, the calibration temperature deviation corresponding to each temperature data point can be obtained. The calibration temperature deviation is used to uniformly characterize the degree of change of different calibration temperatures relative to the reference temperature, and serves as a temperature parameter in the subsequent pulse equivalent temperature drift relationship.

[0039] S212. Obtain the temperature change sequence of the integrated circuit packaging device under each of the temperature data, and determine the calibration temperature state corresponding to each of the temperature data when the temperature change rate of the temperature change sequence meets the preset thermal stability condition. When the equipment temperature first reaches the set value, the internal temperature of the motion platform, transmission mechanism, and equipment base may not yet be stable, and their thermal deformation state is still in the process of change. Therefore, the equipment temperature is continuously acquired at various temperature data points to form a corresponding temperature change sequence, and the degree of temperature change of the equipment is judged based on the temperature change sequence. When the temperature change rate meets the preset thermal stability condition, it indicates that the equipment has entered a relatively stable thermal state at that temperature. This state is determined as the corresponding calibration temperature state to improve the stability of subsequent pulse equivalent calibration results.

[0040] S213. Under each of the calibration temperature conditions, control the motion platform to sequentially execute forward calibration pulse displacement and reverse calibration pulse displacement along the preset calibration direction, and obtain the forward actual displacement and reverse actual displacement corresponding to the forward calibration pulse displacement and the reverse calibration pulse displacement, respectively. After confirming that the equipment has reached the corresponding calibration temperature, the motion platform is controlled to move forward and backward along the preset calibration direction, and the calibration pulse displacement and actual displacement corresponding to the two movement directions are recorded. The forward and reverse actual displacements are used to reflect the actual unit pulse response of the motion platform in different movement directions under the current temperature condition, thus providing a data basis for identifying the directional differences of the transmission mechanism and calculating the pulse equivalent.

[0041] S214. Based on the forward calibration pulse displacement, the reverse calibration pulse displacement, the forward actual displacement, and the reverse actual displacement, determine the forward pulse equivalent, reverse pulse equivalent, and directional hysteresis parameter corresponding to each calibration temperature state. Based on the correspondence between the forward calibration pulse displacement and the actual forward displacement, the forward pulse equivalent under the current calibration temperature can be determined; similarly, based on the correspondence between the reverse calibration pulse displacement and the actual reverse displacement, the reverse pulse equivalent can be determined. Furthermore, based on the difference in displacement response between forward and reverse motion, a directional hysteresis parameter is determined. This directional hysteresis parameter characterizes the displacement difference caused by transmission backlash or transmission lag when the motion platform changes direction, thus avoiding directly treating the error caused by directional hysteresis as temperature drift.

[0042] S215. Based on the directional hysteresis parameter corresponding to each calibration temperature state and the dispersion of the pulse equivalent obtained from multiple repeated calibrations, the positive pulse equivalent and the negative pulse equivalent are effectively screened and fused to obtain the target calibration pulse equivalent corresponding to each calibration temperature deviation. Under the same calibration temperature, forward and reverse pulse equivalent calibrations can be performed multiple times, and the stability of the calibration data can be determined based on the dispersion of the multiple calibration results. Simultaneously, by combining the corresponding directional hysteresis parameters, pulse equivalent data significantly affected by transmission backlash, platform vibration, or measurement anomalies can be identified. Valid forward and reverse pulse equivalents are fused to obtain the target calibration pulse equivalent associated with the corresponding calibration temperature deviation, thereby reducing the impact of directional errors and random measurement errors on the temperature drift relationship.

[0043] S216. Based on the changing trend of the target calibration pulse equivalent corresponding to each calibration temperature deviation, the preset working temperature range is divided into several different temperature intervals. Following the order of calibrated temperature deviations, the trend of pulse equivalent changes with temperature for each target calibration is analyzed. When there are differences in the rate or direction of change of pulse equivalent within different temperature ranges, the preset operating temperature range is divided into several different temperature intervals. Through partitioning, the pulse equivalent change pattern within each temperature interval can be made relatively consistent, providing a basis for subsequently establishing the temperature drift relationship corresponding to each temperature interval.

[0044] S217. Fit the calibration temperature deviation and the target calibration pulse equivalent in each of the temperature ranges to obtain the preset pulse equivalent temperature drift relationship. For each temperature range obtained in step S216, a correspondence between the calibrated temperature deviation and the target calibrated pulse equivalent within that temperature range is established. The fitting results for each temperature range are then combined to obtain a preset pulse equivalent temperature drift relationship covering the preset operating temperature range of the integrated circuit packaging equipment. This temperature drift relationship reflects the variation of the pulse equivalent of the motion platform within different temperature ranges and is used to subsequently determine the current pulse equivalent based on the current temperature.

[0045] In practice, the target calibration pulse equivalent corresponding to different calibration temperature deviations can be obtained when the integrated circuit packaging equipment is in the heating and cooling process, and the calibration data corresponding to the heating and cooling processes can be fitted to obtain the heating temperature drift relationship branch and the cooling temperature drift relationship branch.

[0046] Preferably, step S22 includes: S221. Obtain the temperature data of the integrated circuit packaging device before the current sampling time to obtain the current temperature change sequence; In practice, the device temperature can be continuously acquired at multiple sampling times prior to the current sampling time according to a preset sampling period, and then arranged in chronological order of sampling time to obtain the current temperature change sequence. This current temperature change sequence reflects the temperature change process of the device during the current time period, providing a data basis for subsequent determination of whether the device is in a state of heating up, cooling down, or temperature stability.

[0047] S222. Determine the current temperature change direction and current temperature change rate based on the current temperature change sequence; Based on the changes in temperature data over sampling time in the current temperature change sequence, the current temperature change direction and rate of change can be determined. When the temperature data shows an overall upward trend, the current temperature change direction is determined to be a heating direction; when the temperature data shows an overall downward trend, it is determined to be a cooling direction; in one embodiment, when the temperature data fluctuates within a preset range, it is determined to be a stable temperature state. The current temperature change rate is used to characterize the degree of temperature change of the equipment per unit time, thereby reflecting how quickly the current thermal state of the equipment changes.

[0048] S223. Based on the current temperature change direction, select the corresponding target temperature drift relationship branch from the preset pulse equivalent temperature drift relationship; Because integrated circuit packaging equipment may experience different heat transfer states and thermal deformation processes during heating and cooling, the actual pulse equivalent of the motion platform may differ even at the same temperature. Therefore, the preset pulse equivalent temperature drift relationship can include heating temperature drift branches and cooling temperature drift branches. Based on the current temperature change direction determined in step S222, a target temperature drift branch corresponding to the current temperature change process of the equipment is selected to improve the matching degree between the subsequent pulse equivalent determination result and the actual thermal state of the equipment.

[0049] S224. Determine the temperature range matching range corresponding to the temperature deviation based on the current temperature change rate; The current rate of temperature change reflects whether the equipment's current temperature is still in a rapid change phase. Based on the current rate of temperature change, a corresponding temperature range can be determined near the current temperature deviation. When the temperature change is relatively gradual, the equipment's thermal state is relatively stable, and a temperature range close to the current temperature can be selected within a smaller range. When the temperature change is rapid, the matching range can be appropriately expanded to combine calibration data from adjacent temperature ranges to determine the current stage of temperature drift change for the equipment.

[0050] S225. Match the temperature range matching range with multiple preset temperature ranges included in the target temperature drift relationship branch to obtain at least one candidate temperature range. The temperature range matching range determined in step S224 is compared with each preset temperature range in the target temperature drift relationship branch, and the preset temperature ranges that coincide with the temperature range matching range or meet the preset matching conditions are determined as candidate temperature ranges. The candidate temperature ranges are used to limit the local temperature drift relationship that may correspond to the current temperature, avoiding direct searching within the entire preset operating temperature range.

[0051] S226. Determine the target temperature range from at least one of the candidate temperature ranges based on the distance between the temperature deviation and the endpoints of each candidate temperature range. When multiple candidate temperature ranges are obtained, the proximity between the current temperature deviation and the endpoints of each candidate temperature range is determined, and the candidate temperature range with a higher degree of matching with the current temperature deviation is selected as the target temperature range. This allows the endpoints of the two ranges subsequently used to determine the current pulse equivalent to be closer to the current temperature state of the equipment, improving the accuracy of temperature drift compensation for the current pulse equivalent.

[0052] Preferably, the calibration plate includes a low thermal expansion substrate and a plurality of calibration features disposed on the low thermal expansion substrate, wherein the plurality of calibration features are arranged at a preset interval, the low thermal expansion substrate is made of at least one of microcrystalline glass, ceramic and quartz glass, and the calibration features include at least one of circular features, square features, cross-shaped features and checkerboard corner dots. The calibration plate is used to provide a stable image recognition reference with known positional relationships during visual calibration. The low thermal expansion substrate refers to a plate-shaped substrate with minimal dimensional changes due to temperature variations. It can be made of materials such as microcrystalline glass, ceramic, or quartz glass to reduce calibration errors introduced by the expansion and contraction of the calibration plate itself due to temperature changes, ensuring that the actual positional relationships between calibration features remain relatively stable under different temperature conditions. Multiple calibration features are arranged on the low thermal expansion substrate at preset intervals. These preset intervals can be pre-determined based on the imaging module's field of view, image resolution, and calibration accuracy requirements, enabling the imaging module to identify one or more calibration features at different positions and determine the corresponding pixel displacement of the motion platform using their positional changes. Calibration features can be circular, square, cross-shaped, or checkerboard corner points, etc., which facilitate contour extraction, center positioning, or corner detection. Calibration features of different shapes can be set individually or in combination. By using a low thermal expansion substrate and multiple regularly arranged calibration features, the impact of thermal deformation of the calibration plate and single feature recognition errors on the visual calibration results can be reduced, improving the accuracy of pixel displacement and visual calibration parameter determination under different temperature conditions.

[0053] Step S3 includes: S31. Based on the current pulse equivalent and the preset calibration displacement range, determine the first calibration pulse number and the second calibration pulse number corresponding to the first and second directions of the motion platform along the device coordinate system, respectively. The preset calibration displacement range is used to limit the actual movement distance of the motion platform during visual calibration, ensuring that the calibration features are within the effective field of view of the imaging module before and after the movement, and that the pixel displacement is sufficient to meet the visual calibration accuracy requirements. Based on the current pulse equivalent, the calibration displacements corresponding to the first and second directions are converted into the first calibration pulse number and the second calibration pulse number, respectively, so that the motion platform produces an actual displacement that meets the calibration requirements under the current temperature conditions.

[0054] S32. Control the motion platform to move to the initial calibration position where the calibration feature is within the preset calibration field of view of the imaging module; The initial calibration position is the starting position when performing visual calibration in different directions. Specifically, the motion platform is controlled to move so that the calibration features on the calibration plate enter the preset calibration field of view of the imaging module, while maintaining a corresponding movement space between the calibration features and the boundary of the field of view. This prevents the calibration features from moving out of the imaging field of view or into edge regions with poor imaging quality when the motion platform subsequently moves along the first or second direction.

[0055] S33. Control the motion platform to move along the first direction by the first calibration pulse number, and acquire the first calibration image group before and after the movement respectively; After the motion platform is in the initial calibration position, the motion drive unit controls the motion platform to move along the first direction for the first calibration pulse number, and the imaging module acquires calibration images before and after the motion platform moves, forming a first calibration image set. The first calibration image set is used to reflect the positional change of the calibration features in the image coordinate system when the motion platform generates actual displacement along the first direction.

[0056] S34. Control the motion platform to move along the second direction by the second calibration pulse number, and acquire the second calibration image group before and after the movement respectively; After acquiring images in the first direction, the motion platform is moved to a position suitable for performing calibration in the second direction, and then moved along the second direction for a second number of calibration pulses. The imaging module acquires calibration images before and after the movement, forming a second calibration image set. This second calibration image set reflects the positional changes of the calibration features in the image coordinate system when the motion platform undergoes actual displacement along the second direction. It is then used, together with the calibration results from the first direction, to determine the visual parameters in different directions.

[0057] S35. Associate the first calibration image group, the second calibration image group and the corresponding calibration pulse number to obtain the visual calibration data corresponding to the current temperature; The first calibration image group is associated with the first calibration pulse number, and the second calibration image group is associated with the second calibration pulse number to form visual calibration data in which image changes and motion control quantities correspond one-to-one. The visual calibration data can simultaneously characterize the pulse motion of the motion platform in different directions at the current temperature and the corresponding image position changes, providing a data basis for subsequently determining the pixel displacement, visual equivalent, and coordinate deflection angle in the first and second directions.

[0058] Preferably, step S4 includes: S41. Determine the target image region containing the calibration feature from the first calibration image group and the second calibration image group respectively; The first and second calibration image sets respectively include calibration images before and after the motion platform moves along the first and second directions. In specific implementations, the target image region containing the calibration features is determined from each calibration image based on the preset position, shape, or grayscale features of the calibration features in the imaging field of view. By performing subsequent processing only on the target image region, the influence of background areas, non-calibrated patterns, and stray light on the recognition of calibration features can be reduced, and the amount of data processed in the image can be decreased.

[0059] S42. Extract feature contours from each of the target image regions to obtain the feature contours of the calibration features before and after the movement. Image processing is performed on each target image region determined in step S41 to identify the boundary between the calibration features and the surrounding background, obtaining the feature contours corresponding to the movement of the platform before and after movement. The feature contours characterize the geometric shape and position of the calibration features in the calibration image, and can be circular, square, cross-shaped, or other pre-defined calibration patterns. Extracting the feature contours before and after movement provides a basis for accurately determining the position coordinates of the calibration features.

[0060] S43. Determine the sub-pixel coordinates of the calibration feature before and after the movement based on each of the described feature contours; Based on the distribution of contour points, geometric centers, or feature intersections in each feature contour, the sub-pixel coordinates of the calibration features before and after the movement of the motion platform are determined. Sub-pixel coordinates refer to position coordinates with higher precision than individual image pixels, which can reduce the impact of pixel dispersion on the calibration feature localization results. Therefore, the image position changes of the calibration features caused by the movement of the motion platform can be more accurately characterized, improving the accuracy of subsequent pixel displacement and visual calibration parameter determination.

[0061] S44. Determine the first pixel displacement based on the sub-pixel coordinates of the calibration feature before and after moving along the first direction; Based on the sub-pixel coordinates of the calibration feature before and after its movement in the first calibration image group, the coordinate change between the two is determined, and this coordinate change is used as the first pixel displacement corresponding to the movement of the motion platform along the first direction. The first pixel displacement may include the displacement components of the calibration feature on the two coordinate axes of the image coordinate system, so as to reflect the actual distance and direction of movement of the calibration feature in the image when the motion platform moves along the first direction of the device coordinate system.

[0062] S45. Determine the second pixel displacement based on the sub-pixel coordinates of the calibration feature before and after moving along the second direction; Based on the sub-pixel coordinates of the calibration features before and after movement in the second calibration image group, the change in image coordinates caused by the movement of the motion platform along the second direction is determined, resulting in the second pixel displacement. The second pixel displacement can also include displacement components on both axes of the image coordinate system. The first and second pixel displacements together reflect the correspondence between different motion directions of the device coordinate system and the image coordinate system, providing data for determining the visual equivalent and coordinate deflection in different directions.

[0063] S46. Based on the dispersion of the first and second pixel displacements obtained from repeated visual calibrations, remove abnormal pixel displacements, and determine the first target pixel displacement and the second target pixel displacement based on the remaining first and second pixel displacements, respectively. To reduce the impact of accidental factors such as motion platform vibration, image noise, and calibration feature recognition deviations on pixel displacement determination results, visual calibration can be performed multiple times under the same calibration conditions to obtain multiple sets of first and second pixel displacements. Based on the dispersion of the multiple sets of first and second pixel displacements, abnormal first and second pixel displacements that deviate from the overall data distribution are identified and removed. Subsequently, the remaining valid first pixel displacements are fused to obtain the first target pixel displacement, and the remaining valid second pixel displacements are fused to obtain the second target pixel displacement. This allows for the acquisition of stable and reliable pixel displacement results when the motion platform moves along the first and second directions, providing an accurate data foundation for subsequent determination of the visual equivalent in the first and second directions, as well as the coordinate deflection angle.

[0064] Preferably, step S5 includes: S51. Based on the first calibration pulse count and the current pulse equivalent, determine the first calibrated actual displacement of the motion platform along the first direction. The first calibration pulse count characterizes the number of control pulses output by the motion drive unit to the motion platform along the first direction, and the current pulse equivalent characterizes the actual displacement corresponding to a unit pulse under the current temperature condition. Based on the first calibration pulse count and the current pulse equivalent, the first calibrated actual displacement generated by the motion platform along the first direction can be determined. Since the current pulse equivalent has been adjusted according to the current temperature of the equipment, the first calibrated actual displacement can reflect the actual movement distance of the motion platform under the current thermal condition, providing a physical displacement reference for subsequent calculation of the visual equivalent in the first direction.

[0065] S52. Based on the second calibration pulse count and the current pulse equivalent, determine the second calibration actual displacement of the motion platform along the second direction; the second calibration pulse count is used to characterize the number of control pulses output by the motion drive unit along the second direction. Based on the second calibration pulse count and the current pulse equivalent, the second calibration actual displacement generated by the motion platform along the second direction can be determined. The first calibration actual displacement and the second calibration actual displacement correspond to different motion directions in the device coordinate system, respectively, so that the visual mapping parameters in different directions can be determined separately to adapt to the situation where there are differences in the motion structure, thermal deformation state, or imaging scale in the two directions.

[0066] S53. Determine the visual equivalent in the first direction based on the correspondence between the first calibrated actual displacement and the first target pixel displacement; The first target pixel displacement is used to characterize the effective pixel movement distance of the calibration feature in the image coordinate system after the motion platform completes the calibration motion along the first direction. By establishing a correspondence between the first actual calibration displacement and the first target pixel displacement, the visual equivalent in the first direction can be determined, which is the actual physical displacement corresponding to a unit pixel displacement in the image in the first direction. In practice, the visual equivalent in the first direction can be determined by the ratio of the magnitude of the first actual calibration displacement to the magnitude of the first target pixel displacement. When performing multiple calibrations or using multiple calibration features, the mean or fitting process can be performed based on multiple sets of actual displacements and pixel displacements. Thus, the first-direction image scale transformation parameters applicable to the current temperature state can be obtained.

[0067] S54. Determine the second directional visual equivalent based on the correspondence between the second calibrated actual displacement and the second target pixel displacement; The second target pixel displacement is used to characterize the effective pixel movement distance of the calibration feature in the image coordinate system when the motion platform moves along the second direction. Based on the proportional relationship between the second calibration actual displacement and the second target pixel displacement, the second-direction visual equivalent can be determined to characterize the actual physical displacement corresponding to a unit pixel displacement in the image in the second direction. The first-direction visual equivalent and the second-direction visual equivalent can be calculated separately, thus adapting to differences in the transmission structure, thermal expansion, imaging scaling ratio, or installation status of the motion platform in different directions, and avoiding coordinate transformation errors in different directions caused by using a single visual equivalent.

[0068] S55. Based on the pixel displacement components of the first target pixel displacement and the second target pixel displacement on the two coordinate axes of the image coordinate system, determine the first projection direction angle and the second projection direction angle of the first direction and the second direction in the image coordinate system, respectively. Both the first and second target pixel displacements can be represented as pixel displacement components on two coordinate axes of the image coordinate system, such as horizontal and vertical pixel displacement components. In practice, the first projection direction angle after projecting the first direction of the device coordinate system onto the image coordinate system can be determined based on the arctangent relationship between the two pixel displacement components of the first target pixel displacement. Similarly, the second projection direction angle is determined based on the two pixel displacement components of the second target pixel displacement. The projection direction angle reflects the actual movement direction of the calibration feature in the image when the motion platform moves along the corresponding device coordinate direction, providing a basis for determining the rotational deviation between the image coordinate system and the device coordinate system.

[0069] S56. Determine the first direction angle difference and the second direction angle difference based on the angle differences between the first projection direction angle and the second projection direction angle and the preset direction angle of the corresponding direction in the device coordinate system. In the device coordinate system, the first direction and the second direction each have corresponding preset direction angles. For example, the first direction can be set as the zero-degree direction in the device coordinate system, and the second direction, which is orthogonal to the first direction, can be set as the ninety-degree direction. By comparing the first projected direction angle with the preset direction angle corresponding to the first direction, the first direction angle difference can be obtained; by comparing the second projected direction angle with the preset direction angle corresponding to the second direction, the second direction angle difference can be obtained. The first direction angle difference and the second direction angle difference respectively reflect the degree of deflection of the two device motion directions in the image coordinate system, thereby reducing the problem of being easily affected by pixel recognition errors when determining the coordinate rotation relationship based on only a single motion direction.

[0070] S57. Determine the coordinate deflection angle between the image coordinate system and the device coordinate system based on the first directional angle difference and the second directional angle difference; Coordinate deflection is used to characterize the overall rotational deviation of the image coordinate system relative to the device coordinate system. In practice, when the difference between the angle difference in the first direction and the angle difference in the second direction is within a preset allowable range, the two can be averaged or weighted and fused to obtain the coordinate deflection. The weights can be determined based on the length of the corresponding pixel displacement, the confidence level of the calibration features, or the dispersion of multiple calibration results. When the difference between the two angle differences exceeds a preset allowable range, it can be determined that there is an anomaly in the current angle calibration, and the visual calibration in the corresponding direction can be re-executed. By integrating angle information from two different directions, the stability and accuracy of the coordinate deflection can be improved.

[0071] S58. Based on the visual equivalent in the first direction, the visual equivalent in the second direction, and the coordinate deflection angle, obtain visual calibration parameters that are adapted to the current temperature.

[0072] The first and second directional visual equivalents are used to characterize the scale correspondence between pixel displacement in the image coordinate system and the actual physical displacement in two motion directions in the device coordinate system, respectively. The coordinate deflection is used to characterize the directional correspondence between the two coordinate systems. By associating and storing the first and second directional visual equivalents and the coordinate deflection, the visual calibration parameters corresponding to the current temperature can be formed. In the subsequent temperature drift compensation process, the target pixel displacement can be first converted to the corresponding direction in the device coordinate system based on the coordinate deflection, and then the pixel displacement can be converted to the actual physical displacement based on the visual equivalents in each direction. Since the above parameters are all determined based on the calibration image acquired at the current pulse equivalent and current temperature, they can adapt to changes in image scale and coordinate direction caused by changes in the thermal state of the device.

[0073] In another embodiment, the visual calibration parameters may further include a coordinate transformation matrix between the image coordinate system and the device coordinate system. Specifically, based on a preset number of pulses for the motion platform to move along at least two non-collinear directions and the current pulse equivalent in the corresponding directions, the actual calibration displacement vector of the motion platform in the device coordinate system is determined. Simultaneously, based on the calibration images before and after the calibration feature movement, the pixel displacement vector corresponding to each actual calibration displacement vector is determined. Coordinate transformation equations are constructed based on the correspondence between multiple sets of actual calibration displacement vectors and pixel displacement vectors, and the coordinate transformation matrix is ​​determined through matrix solving or least-squares fitting. The coordinate transformation matrix can be used to directly convert the target pixel displacement vector in the image coordinate system into the target physical displacement vector in the device coordinate system without separately calculating the visual equivalent and coordinate deflection angle. Furthermore, when the calibration features are distributed at multiple locations in the imaging field of view, an affine transformation matrix, a perspective transformation matrix, or a regional coordinate transformation matrix can be determined based on the data corresponding to multiple calibration locations to adapt to situations with inconsistent imaging scales, non-orthogonal coordinate axes, or local imaging distortion.

[0074] Preferably, step S6 includes: S61. Obtain the current pixel coordinates of the integrated circuit to be processed in the detection image and the target pixel coordinates corresponding to the integrated circuit to be processed; The inspection image is the image acquired by the imaging module at the workstation where the integrated circuit to be processed is located. The current pixel coordinates represent the actual image position of the integrated circuit to be processed in its current state, while the target pixel coordinates represent the image position that the integrated circuit to be processed should reach when completing positioning, mounting, sorting, or inspection operations. By obtaining the current pixel coordinates and the target pixel coordinates, the position adjustment requirements of the integrated circuit to be processed in the image coordinate system can be determined.

[0075] S62. Determine the target pixel displacement of the integrated circuit to be processed in the image coordinate system based on the current pixel coordinates and the target pixel coordinates; Based on the positional difference between the target pixel coordinates and the current pixel coordinates, the distance and direction that the integrated circuit to be processed needs to move in the image coordinate system are determined, thus obtaining the target pixel displacement. This target pixel displacement characterizes the pixel change on each of the two coordinate axes of the image coordinate system when the integrated circuit to be processed moves from its current position to the target position, and serves as input data for subsequent coordinate rotation transformations.

[0076] S63. Based on the coordinate deflection angle, perform coordinate rotation transformation on the target pixel displacement to obtain the first direction pixel displacement and the second direction pixel displacement corresponding to the target pixel displacement in the first direction and the second direction in the device coordinate system, respectively. The image coordinate system and the device coordinate system may have coordinate offsets due to the installation deviation of the imaging module and thermal deformation of the device. Therefore, the target pixel displacement cannot be directly used as the displacement basis for different motion directions of the motion platform. Based on the coordinate offset determined in step S5, a coordinate rotation transformation is performed on the target pixel displacement to convert it to the device coordinate system and decompose it into the first direction pixel displacement and the second direction pixel displacement. This can reduce the motion control error caused by the inconsistency between the image coordinate axes and the motion direction of the motion platform.

[0077] S64. Based on the visual equivalent in the first direction and the pixel displacement in the first direction, determine the physical displacement of the first target corresponding to the motion platform along the first direction; The first-direction visual equivalent is used to characterize the actual physical displacement corresponding to a unit pixel displacement in the first direction under the current temperature condition. Based on the first-direction visual equivalent and the first-direction pixel displacement, the first target physical displacement that the motion platform needs to generate along the first direction can be determined. Since the first-direction visual equivalent is adapted to the current temperature, the first target physical displacement can reflect the actual position adjustment requirements of the device under the current thermal condition.

[0078] S65. Based on the visual equivalent in the second direction and the pixel displacement in the second direction, determine the physical displacement of the second target corresponding to the motion platform along the second direction; Based on the visual equivalent of the second direction, the pixel displacement in the second direction is converted into the second target physical displacement that the motion platform needs to generate along the second direction. The first target physical displacement and the second target physical displacement correspond to two motion directions in the device coordinate system, which together limit the actual amount of motion required for the motion platform to move the integrated circuit to be processed from its current position to the target position.

[0079] S66. Determine the number of motion pulses of the first target based on the physical displacement of the first target and the current pulse equivalent corresponding to the first direction; The current pulse equivalent corresponding to the first direction is used to characterize the actual displacement generated by the motion platform when the motion drive unit outputs a unit pulse along the first direction under the current temperature condition. Based on the first target physical displacement and the current pulse equivalent corresponding to the first direction, the actual motion requirement in the first direction can be converted into the first target motion pulse number that the motion drive unit can execute, so as to compensate for the displacement reference drift of the first direction transmission mechanism caused by temperature changes.

[0080] S67. Determine the number of motion pulses of the second target based on the physical displacement of the second target and the current pulse equivalent corresponding to the second direction; Based on the physical displacement of the second target and the current pulse equivalent corresponding to the second direction, the number of motion pulses corresponding to the second target when the motion platform moves along the second direction is determined. By converting the pulse equivalents corresponding to the two directions at the current temperature, it is possible to adapt to the differences in transmission structures and temperature drift characteristics in different motion directions, thereby improving the accuracy of motion control quantities in different directions.

[0081] S68. Generate a temperature drift compensation motion control command based on the first target motion pulse count and the second target motion pulse count to control the motion platform to move the integrated circuit to be processed to the target position.

[0082] The first target motion pulse count and the second target motion pulse count are combined according to the control method of the motion platform to generate a temperature drift compensation motion control command, which is then sent to the motion drive unit. The motion drive unit drives the motion platform to move along the first and second directions accordingly, moving the integrated circuit to be processed to the target position. Since the motion control command is generated based on both the visual calibration parameters at the current temperature and the current pulse equivalent, it can jointly compensate for the temperature drift of the visual coordinate mapping relationship and the displacement reference of the motion platform.

[0083] Preferably, after step S6, the method further includes: S7. Verify the effectiveness of the temperature drift compensation motion result of the motion platform.

[0084] After the motion platform completes its movement according to the temperature drift compensation motion control command, the actual arrival position of the integrated circuit to be processed is detected again, and it is determined whether the deviation between it and the target position meets the equipment positioning accuracy requirements. This step verifies whether the current pulse equivalent and visual calibration parameters match the current temperature state of the equipment, avoiding the direct use of unverified temperature drift compensation results in subsequent packaging or packaging inspection operations. Specifically, step S7 includes: S71. Acquire a compensation verification image of the integrated circuit to be processed after it has been moved using the imaging module; First, after the motion platform completes the temperature drift compensation motion and reaches a stable state, the imaging module re-acquires an image of the location of the integrated circuit to be processed, obtaining a compensation verification image. This compensation verification image reflects the actual position of the integrated circuit after the temperature drift compensation motion, providing image data for subsequent determination of the compensation residual.

[0085] S72. Extract the compensated pixel coordinates of the integrated circuit to be processed from the compensated verification image; The contour, center, pads, pins, or preset positioning features of the integrated circuit to be processed are identified from the compensation verification image. Based on the identification results, the pixel position of the integrated circuit to be processed after completing the temperature drift compensation movement is determined, and the compensated pixel coordinates are obtained. The compensated pixel coordinates are used to characterize the actual arrival position of the integrated circuit to be processed.

[0086] S73. Determine the compensation residual vector in the image coordinate system based on the compensated pixel coordinates and the target pixel coordinates; The compensated pixel coordinates are compared with the target pixel coordinates to determine the pixel deviation of the actual arrival position of the integrated circuit to be processed relative to the target position, thus obtaining the compensation residual vector. The compensation residual vector includes residual components on different coordinate axes of the image coordinate system, which are used to characterize the positional deviation and its direction that still exist after the temperature drift compensation motion is completed.

[0087] S74. Based on the coordinate deflection angle, convert the compensation residual vector into a first-direction compensation residual and a second-direction compensation residual in the device coordinate system; Since the compensation residual vector is determined in the image coordinate system, while the motion control of the motion platform is executed based on the device coordinate system, a coordinate transformation is performed on the compensation residual vector according to the coordinate deflection angle between the image coordinate system and the device coordinate system. This yields the compensation residuals corresponding to the first and second directions in the device coordinate system, respectively. By representing the compensation residuals by direction, it is possible to determine which direction of motion the positioning error mainly originates from, providing a basis for subsequently selecting the calibration parameters that need to be updated.

[0088] S75. Compare the first direction compensation residual and the second direction compensation residual with the corresponding preset direction residual thresholds respectively; The first and second directions can be set with corresponding preset residual thresholds according to the positioning accuracy requirements of the equipment. By comparing the compensation residuals of the two directions with their corresponding residual thresholds, it can be determined whether the temperature drift compensation results of the motion platform in each motion direction meet the requirements, and avoid failing to identify local directional errors based solely on the overall residual magnitude.

[0089] S76. When both the first direction compensation residual and the second direction compensation residual are less than or equal to the corresponding preset direction residual threshold, determine that the current pulse equivalent and the visual calibration parameter have passed the compensation validity verification. When the compensation residuals in both directions are within the allowable range, it indicates that the temperature drift compensation motion control command generated based on the current pulse equivalent and visual calibration parameters can bring the integrated circuit to be processed to a position that meets the accuracy requirements. Therefore, it can be determined that the current pulse equivalent and visual calibration parameters are suitable for the current temperature state of the equipment and can be used for the positioning and motion control of subsequent integrated circuits to be processed.

[0090] S77. When at least one of the first direction compensation residual and the second direction compensation residual is greater than the corresponding preset direction residual threshold, the calibration parameter to be updated is determined according to the target direction that exceeds the preset direction residual threshold. When the compensation residual in at least one direction exceeds the corresponding threshold, it indicates that the currently used visual equivalent, pulse equivalent, or related coordinate transformation parameters for that direction fail to adequately reflect the current thermal state of the equipment. The direction with the excessive residual is identified as the target direction, and the calibration parameters to be updated are determined based on the correspondence between the target direction and the visual calibration parameters. Therefore, parameter updates can be performed only for directions where the compensation effect does not meet the requirements, without having to re-perform a complete calibration for all directions.

[0091] S78. Control the motion platform to re-perform visual calibration along the target direction, and update the visual equivalent and current pulse equivalent corresponding to the target direction based on the pixel displacement obtained from the re-perform visual calibration; When the compensation residual corresponding to the target direction exceeds the preset direction residual threshold, it indicates a deviation between the motion control parameters or visual mapping parameters currently used in that direction and the actual thermal state of the device. In specific implementation, the current temperature of the integrated circuit packaging device is re-acquired, and the temperature deviation corresponding to the re-acquired current temperature is matched with the preset pulse equivalent temperature drift relationship to update the current pulse equivalent corresponding to the target direction. Subsequently, based on the updated current pulse equivalent, the motion platform is controlled to re-execute calibration pulse motion along the target direction, and calibration images before and after the calibration board movement are acquired through the imaging module to redetermine the pixel displacement corresponding to the target direction. Based on the number of calibration pulses used in the re-execution of visual calibration and the updated current pulse equivalent, the actual calibration displacement corresponding to the target direction is determined. Then, based on the correspondence between the actual calibration displacement and the newly determined pixel displacement, the visual equivalent corresponding to the target direction is updated. Thus, the current pulse equivalent is updated based on the re-acquired temperature state of the device, while the visual equivalent is updated based on the updated current pulse equivalent and the re-acquired visual calibration data, avoiding the problem of unclear parameter update basis caused by simultaneously correcting two parameters based solely on pixel displacement. By recalibrating only the target direction where the compensation residual exceeds the limit, the range of parameter updates can be narrowed and the time required for recalibration can be reduced.

[0092] S79. Based on the updated visual equivalent and the current pulse equivalent, redetermine the number of target motion pulses corresponding to the target direction, and control the motion platform to perform temperature drift compensation motion again.

[0093] After updating the target direction parameters, the remaining pixel position deviation in that direction is converted into target physical displacement based on the updated visual equivalent. Then, the corresponding target motion pulse number is determined based on the updated current pulse equivalent. Subsequently, the motion platform is controlled to perform temperature drift compensation motion again along the target direction to further reduce the deviation between the actual position and the target position of the integrated circuit to be processed, thus forming a closed-loop control process of temperature drift compensation parameter determination, motion execution, visual verification, and parameter correction.

[0094] Example 2 This invention provides a temperature drift compensation system for integrated circuit packaging equipment based on visual calibration. The system includes a motion platform, a motion drive unit, an imaging module, a temperature acquisition module, a calibration board, and a processor. The motion platform is used to carry the integrated circuit to be processed and / or the calibration board; the motion drive unit is connected to the motion platform for driving the motion platform to move in different directions of the device coordinate system according to motion control commands, and outputting motion pulse data corresponding to the motion platform; the calibration board is provided with calibration features for visual calibration; the imaging module is positioned facing the motion platform and is used to acquire calibration images of the calibration features before and after the motion platform moves, as well as to acquire detection images of the integrated circuit to be processed; the temperature acquisition module is used to acquire the current temperature of the integrated circuit packaging equipment; the processor is communicatively connected to the motion drive unit, the imaging module and the temperature acquisition module respectively to implement the method of Embodiment 1.

[0095] In this embodiment, the motion platform provides a motion carrier for the positioning, handling, mounting, or inspection of the integrated circuit to be processed, and can carry the calibration board during the visual calibration process, enabling the calibration features on the calibration board to move relative to the imaging module in different directions along the device coordinate system. The motion drive unit may include a servo motor, a stepper motor, a lead screw transmission mechanism, a linear guide rail, and a corresponding driver, used to convert the motion control commands generated by the processor into the actual displacement of the motion platform and to feed back the corresponding motion pulse data to the processor.

[0096] The calibration board is equipped with dots, squares, crosses, or other calibration features that can be stably identified by the imaging module, providing a unified visual position reference before and after the motion platform moves. The imaging module may include an industrial camera, lens, and light source, which is oriented towards the motion platform to acquire calibration images before and after the calibration features move, and to acquire inspection images of the integrated circuit to be processed when the equipment performs packaging or packaging inspection operations.

[0097] The temperature acquisition module can be set in the motion platform, motion drive unit, imaging module installation location, or inside the device. It is used to collect temperature data that can characterize the current thermal state of the integrated circuit packaging device and send the collected current temperature to the processor.

[0098] The processor determines the current pulse equivalent of the motion platform at the current temperature and controls the motion drive unit to drive the motion platform to perform visual calibration motion. The processor also determines the pixel displacement of the calibration features based on the calibration image acquired by the imaging module, thereby determining the visual equivalent and coordinate deflection angle adapted to the current temperature. When locating the integrated circuit to be processed, the processor converts the target pixel position of the integrated circuit to be processed into the target motion pulse number based on the visual equivalent, coordinate deflection angle, and current pulse equivalent, and controls the motion drive unit to drive the motion platform, thereby achieving joint temperature drift compensation for the visual coordinate transformation relationship and the motion platform displacement reference.

[0099] Specifically, the processor may include a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement embodiments of the present invention.

[0100] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0101] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0102] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0103] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0104] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0105] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0106] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for temperature drift compensation in integrated circuit packaging equipment based on visual calibration, characterized in that, An integrated circuit packaging device, comprising an imaging module for acquiring images and a temperature acquisition module for acquiring temperature information of the integrated circuit packaging device, the method comprising: The current temperature of the integrated circuit packaging equipment is obtained, and the temperature deviation is determined based on the current temperature and the reference temperature. Based on the temperature deviation and the preset pulse equivalent temperature drift relationship, the current pulse equivalent of the motion platform of the integrated circuit packaging equipment at the current temperature is determined. The preset pulse equivalent temperature drift relationship is a data relationship established in advance based on the temperature deviation and corresponding pulse equivalent at multiple calibration temperatures, used to characterize the correspondence between temperature deviation and pulse equivalent. Based on the current pulse equivalent, the motion platform is controlled to move the calibration plate with calibration features along different directions of the device coordinate system for a preset number of pulses, and the imaging module is used to acquire calibration images of the calibration plate before and after the movement. Based on the calibration image, determine the pixel displacement of the calibration feature in different directions; Based on the current pulse equivalent, the preset pulse number, and the pixel displacement, visual calibration parameters adapted to the current temperature are determined, wherein the visual calibration parameters are used to characterize the coordinate mapping relationship between the image coordinate system and the device coordinate system; Based on the visual calibration parameters and the current pulse equivalent, the target pixel position of the integrated circuit to be processed is converted by temperature drift compensation to obtain the target motion pulse number used to control the motion of the motion platform.

2. The method according to claim 1, characterized in that, The step of determining the current pulse equivalent of the motion platform at the current temperature based on the temperature deviation and the preset pulse equivalent temperature drift relationship includes: Based on the preset temperature set and the reference temperature, a preset pulse equivalent temperature drift relationship is constructed. The preset temperature set includes several different temperature data within the preset operating temperature range of the integrated circuit packaging equipment. Based on the position of the temperature deviation in the preset pulse equivalent temperature drift relationship, the target temperature range corresponding to the current temperature is determined; Obtain the first calibration temperature deviation, the second calibration temperature deviation, the first calibration pulse equivalent, and the second calibration pulse equivalent corresponding to the two endpoints of the target temperature range, respectively; Based on the temperature deviation, the first calibration temperature deviation, and the second calibration temperature deviation, determine the temperature position coefficient of the current temperature within the target temperature range; Based on the first calibrated pulse equivalent, the second calibrated pulse equivalent, and the temperature position coefficient, the current pulse equivalent of the motion platform at the current temperature is determined.

3. The method according to claim 2, characterized in that, The step of constructing the preset pulse equivalent temperature drift relationship based on the preset temperature set and the reference temperature includes: Based on the temperature data in the preset temperature set and the reference temperature, determine the calibration temperature deviation corresponding to each temperature data. The temperature change sequence of the integrated circuit packaging equipment under each of the temperature data is obtained, and when the temperature change rate of the temperature change sequence meets the preset thermal stability condition, the calibration temperature state corresponding to each of the temperature data is determined. Under each of the specified calibration temperature conditions, the motion platform is controlled to sequentially execute forward calibration pulse displacement and reverse calibration pulse displacement along the preset calibration direction, and the forward actual displacement and reverse actual displacement corresponding to the forward calibration pulse displacement and the reverse calibration pulse displacement are obtained respectively. Based on the forward calibration pulse displacement, the reverse calibration pulse displacement, the forward actual displacement, and the reverse actual displacement, determine the forward pulse equivalent, reverse pulse equivalent, and directional hysteresis parameter corresponding to each calibration temperature state; Based on the directional hysteresis parameter corresponding to each calibration temperature state and the dispersion of the pulse equivalent obtained from multiple repeated calibrations, the positive pulse equivalent and the negative pulse equivalent are effectively screened and fused to obtain the target calibration pulse equivalent corresponding to each calibration temperature deviation. Based on the changing trend of the target calibration pulse equivalent corresponding to each calibration temperature deviation, the preset working temperature range is divided into several different temperature intervals. The preset pulse equivalent temperature drift relationship is obtained by fitting the calibration temperature deviation and the target calibration pulse equivalent within each of the temperature ranges.

4. The method according to claim 2, characterized in that, The step of determining the target temperature range corresponding to the current temperature based on the corresponding position of the temperature deviation in the preset pulse equivalent temperature drift relationship includes: Obtain the temperature data of the integrated circuit packaging device prior to the current sampling time to obtain the current temperature change sequence; The current temperature change direction and current temperature change rate are determined based on the current temperature change sequence, wherein the current temperature change direction includes a heating direction and a cooling direction. Based on the current temperature change direction, select the corresponding target temperature drift relationship branch from the preset pulse equivalent temperature drift relationship, wherein the preset pulse equivalent temperature drift relationship includes a temperature rise temperature drift relationship branch and a temperature fall temperature drift relationship branch; Based on the current rate of temperature change, determine the temperature range matching range corresponding to the temperature deviation; The temperature range matching range is matched with multiple preset temperature ranges included in the target temperature drift relationship branch to obtain at least one candidate temperature range; The target temperature range is determined from at least one of the candidate temperature ranges based on the distance between the temperature deviation and the endpoints of each candidate temperature range.

5. The method according to claim 1, characterized in that, The calibration plate includes a low thermal expansion substrate and a plurality of calibration features disposed on the low thermal expansion substrate. The plurality of calibration features are arranged at a preset interval. The low thermal expansion substrate is made of at least one of microcrystalline glass, ceramic, and quartz glass. The calibration features include at least one of circular features, square features, cross-shaped features, and checkerboard corner points. Based on the current pulse equivalent, the motion platform is controlled to move the calibration plate with calibration features disposed thereon along different directions of the device coordinate system for a preset number of pulses, and the calibration images of the calibration plate before and after the movement are acquired by the imaging module, including: Based on the current pulse equivalent and the preset calibration displacement range, determine the first calibration pulse number and the second calibration pulse number corresponding to the first and second directions of the motion platform along the device coordinate system, respectively; Control the motion platform to move to the initial calibration position where the calibration feature is within the preset calibration field of view of the imaging module; The motion platform is controlled to move along the first direction by the first number of calibration pulses, and the first calibration image group before and after the movement is acquired respectively; The motion platform is controlled to move along the second direction by the second calibration pulse number, and the second calibration image group before and after the movement is acquired respectively; By associating the first calibration image group, the second calibration image group, and the corresponding calibration pulse number, visual calibration data corresponding to the current temperature is obtained.

6. The method according to claim 5, characterized in that, Determining the pixel displacement of the calibration feature in different directions based on the calibration image includes: Target image regions containing the calibration features are determined from the first calibration image group and the second calibration image group, respectively; Feature contours are extracted from each of the target image regions to obtain the feature contours of the calibration features before and after the movement. The sub-pixel coordinates of the calibrated features before and after movement are determined based on the feature contours described above; The first pixel displacement is determined based on the sub-pixel coordinates of the calibration features before and after moving along the first direction. The second pixel displacement is determined based on the sub-pixel coordinates of the calibration feature before and after moving along the second direction. Based on the dispersion of the first and second pixel displacements obtained from repeated visual calibration, abnormal pixel displacements are removed, and the first and second target pixel displacements are determined based on the remaining first and second pixel displacements, respectively.

7. The method according to claim 6, characterized in that, The step of determining visual calibration parameters adapted to the current temperature based on the current pulse equivalent, the preset pulse number, and the pixel displacement includes: Based on the first calibration pulse count and the current pulse equivalent, the first calibration actual displacement of the motion platform along the first direction is determined; Based on the second calibration pulse count and the current pulse equivalent, determine the second calibration actual displacement of the motion platform along the second direction; The first directional visual equivalent is determined based on the correspondence between the first calibrated actual displacement and the first target pixel displacement; The second directional visual equivalent is determined based on the correspondence between the second calibrated actual displacement and the second target pixel displacement; Based on the pixel displacement components of the first target pixel displacement and the second target pixel displacement on the two coordinate axes of the image coordinate system, the first projection direction angle and the second projection direction angle of the first direction and the second direction in the image coordinate system are determined respectively. The first direction angle difference and the second direction angle difference are determined based on the angle differences between the first projection direction angle and the second projection direction angle and the preset direction angle of the corresponding direction in the device coordinate system. Based on the first directional angle difference and the second directional angle difference, determine the coordinate deflection angle between the image coordinate system and the device coordinate system; Based on the visual equivalent in the first direction, the visual equivalent in the second direction, and the coordinate deflection angle, visual calibration parameters adapted to the current temperature are obtained.

8. The method according to claim 7, characterized in that, The step of performing temperature drift compensation conversion on the target pixel position of the integrated circuit to be processed based on the visual calibration parameters and the current pulse equivalent to obtain the target motion pulse number used to control the motion platform includes: Obtain the current pixel coordinates of the integrated circuit to be processed in the detected image and the target pixel coordinates corresponding to the integrated circuit to be processed; Based on the current pixel coordinates and the target pixel coordinates, determine the target pixel displacement of the integrated circuit to be processed in the image coordinate system; Based on the coordinate deflection angle, the target pixel displacement is subjected to coordinate rotation transformation to obtain the first direction pixel displacement and the second direction pixel displacement corresponding to the target pixel displacement in the first direction and the second direction in the device coordinate system, respectively. Based on the visual equivalent in the first direction and the pixel displacement in the first direction, the physical displacement of the motion platform along the first direction corresponding to the first target is determined; Based on the visual equivalent in the second direction and the pixel displacement in the second direction, the physical displacement of the motion platform along the second direction corresponding to the second target is determined; The number of motion pulses of the first target is determined based on the physical displacement of the first target and the current pulse equivalent corresponding to the first direction; The number of motion pulses of the second target is determined based on the physical displacement of the second target and the current pulse equivalent corresponding to the second direction; Based on the first target motion pulse count and the second target motion pulse count, a temperature drift compensation motion control command is generated to control the motion platform to move the integrated circuit to be processed to the target position.

9. The method according to claim 8, characterized in that, After controlling the motion platform to move the integrated circuit to be processed to the target position, the method further includes: The imaging module acquires a compensation verification image of the integrated circuit to be processed after it has been moved. Extract the compensated pixel coordinates of the integrated circuit to be processed from the compensated verification image; Based on the compensated pixel coordinates and the target pixel coordinates, determine the compensation residual vector in the image coordinate system; Based on the coordinate deflection angle, the compensation residual vector is converted into a first-direction compensation residual and a second-direction compensation residual in the device coordinate system; The first direction compensation residual and the second direction compensation residual are compared with the corresponding preset direction residual thresholds, respectively; When both the first-direction compensation residual and the second-direction compensation residual are less than or equal to the corresponding preset direction residual threshold, it is determined that the current pulse equivalent and the visual calibration parameter have passed the compensation validity verification. When at least one of the first direction compensation residual and the second direction compensation residual is greater than the corresponding preset direction residual threshold, the calibration parameter to be updated is determined according to the target direction that exceeds the preset direction residual threshold; The motion platform is controlled to re-perform visual calibration along the target direction, and the visual equivalent and current pulse equivalent corresponding to the target direction are updated based on the pixel displacement obtained from the re-perform visual calibration. Based on the updated visual equivalent and the current pulse equivalent, the number of target motion pulses corresponding to the target direction is re-determined, and the motion platform is controlled to perform temperature drift compensation motion again.

10. A temperature drift compensation system for integrated circuit packaging equipment based on vision calibration, characterized in that, The system includes a motion platform, a motion drive unit, an imaging module, a temperature acquisition module, a calibration board, and a processor. The motion platform is used to carry the integrated circuit to be processed and / or the calibration board; the motion drive unit is connected to the motion platform for driving the motion platform to move in different directions of the device coordinate system according to motion control commands, and outputting motion pulse data corresponding to the motion platform; the calibration board is provided with calibration features for visual calibration; the imaging module is positioned facing the motion platform and is used to acquire calibration images of the calibration features before and after the motion platform moves, as well as to acquire detection images of the integrated circuit to be processed; the temperature acquisition module is used to acquire the current temperature of the integrated circuit packaging equipment; the processor is communicatively connected to the motion drive unit, the imaging module and the temperature acquisition module respectively, to implement the method described in any one of claims 1-9.

Images