Alignment system, alignment method, and program

Abstract

An alignment system (1) comprises: an image processing unit (400) for obtaining the center of vibration of a representative point of a workpiece (10) on the basis of a captured image of the workpiece (10), and determining whether the obtained center is within the accuracy reference range of a predetermined representative point; and an operation control unit (200) for controlling drive devices (111, 112, 113) that move the workpiece (10). The operation control unit (200) controls the drive devices (111, 112, 113) on the basis of the result determined by the image processing unit (400).

Description

Alignment system, alignment method and program

[0001] The present disclosure relates to an alignment system, an alignment method, and a program.

[0002] Alignment techniques are known that align the position of a workpiece, which is a controlled object, to a reference position. For example, in Patent Document 1, an image is captured after vibrations of a microscope have subsided to an extent that the detection accuracy of the position of the controlled object is not affected, and alignment is performed based on the captured image.

[0003] Japanese Patent Application Laid-Open No. 2009-231671

[0004] In alignment, waiting for vibration to settle significantly affects the takt time. Since vibration of the workpiece to be aligned is an issue in alignment, it is necessary to take workpiece vibration into consideration. However, Patent Document 1 does not take workpiece vibration into consideration. Therefore, alignment that takes workpiece vibration into consideration is required.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide an alignment system, an alignment method, and a program that take into account the vibration of a workpiece.

[0006] To achieve the above object, the alignment system according to the present disclosure includes an image processing unit and a motion control unit. The image processing unit determines the center of vibration of a representative point of the workpiece based on a captured image of the workpiece, and determines whether the determined center is within a predetermined range of accuracy standards for the representative point. The motion control unit controls a driving device that moves the workpiece. The motion control unit controls the driving device based on the result determined by the image processing unit.

[0007] According to the present disclosure, the center of vibration of a representative point of a workpiece is determined based on a captured image, and the driving device is controlled based on the determined center, thereby enabling alignment that takes the vibration of the workpiece into consideration.

[0008] FIG. 1 is a block diagram showing an example of the overall configuration of an alignment system according to the first embodiment; FIG. 2 is a block diagram showing an example of the configuration of an operation control unit according to the first embodiment; FIG. 3 is a block diagram showing an example of the configuration of an image processing unit according to the first embodiment; FIG. 4 is a diagram explaining an alignment control method according to the first embodiment; FIG. 5 is a diagram explaining an alignment control method according to the first embodiment;

[0009] An alignment system, an alignment method, and a program according to this embodiment will be described in detail below with reference to the drawings. Note that the same or corresponding parts in the drawings are designated by the same reference numerals.

[0010] 1 is a block diagram showing an example of the overall configuration of an alignment system 1 according to embodiment 1. The alignment system 1 includes an alignment mechanism 100 that moves a workpiece 10, an operation control unit 200 that controls the alignment mechanism 100, an imaging device 300 that images the workpiece 10, an image processing unit 400 that processes the image captured by the imaging device 300, and a setting terminal 500 that sets various settings used in processing by the image processing unit 400.

[0011] The alignment mechanism 100 includes a mounting table 101 on which the workpiece 10 is placed, and actuators 111, 112, and 113 that mount the mounting table 101 and adjust its position. The actuators 111, 112, and 113 are collectively referred to as an X-Y-θ stage, which moves the mounting table 101 in the X-axis direction, the Y-axis direction perpendicular to the X-axis, and around the θ-axis perpendicular to the X-Y plane. For example, the actuator 111 is an X-stage that moves in the X-axis direction, the actuator 112 is a Y-stage that moves in the Y-axis direction perpendicular to the X-axis direction, and the actuator 113 is a θ-stage that rotates around a rotation axis. These are arranged one on top of the other, and the mounting table 101 is placed on them. The actuators 111, 112, and 113 each include an actuator, such as a servomotor. Drive control devices 121, 122, and 123 are connected to the actuators 111, 112, and 113, respectively.

[0012] The driving devices 111, 112, and 113 each have an internal or external position sensor that detects and outputs the position of the driving devices 111, 112, and 113. The position sensor is, for example, an encoder attached to the actuator. The output signal of the encoder is input to the motion control unit 200 via the drive control devices 121, 122, and 123.

[0013] The drive control devices 121, 122, 123, the motion control unit 200, the image processing unit 400, and the imaging device 300 are connected to one another for communication. The communication means may be any conventional communication means such as Ethernet (registered trademark), CameraLink, CoaxPress (registered trademark), or USB (Universal Serial Bus, registered trademark), but to ensure synchronism, an Ethernet-based industrial network such as CC-Link IE / field (registered trademark) or CC-Link IE / TSN (registered trademark) is preferred.

[0014] Drive control devices 121, 122, and 123 are control devices, such as servo amplifiers, that control the operations of drive devices 111, 112, and 113, respectively, based on control signals from motion control unit 200.

[0015] The motion control unit 200 is a motion controller that issues commands related to the operations of the movable devices 111, 112, and 113 to the drive control devices 121, 122, and 123, and includes, for example, a PLC (Programmable Logic Controller). The motion control unit 200 generates control signals indicating commands based on information acquired from the drive control devices 121, 122, and 123 and the image processing unit 400, and outputs the control signals to the drive control devices 121, 122, and 123.

[0016] 2, the operation control unit 200 includes a processor 210, a volatile memory 220, a non-volatile memory 230, a clock 240, and a communication interface 250. The processor 210, the volatile memory 220, the non-volatile memory 230, the clock 240, and the communication interface 250 are communicatively connected to one another via a bus B1.

[0017] The processor 210 includes, for example, a CPU (Central Processing Unit), and functions as a movement amount calculation unit 212 and a command unit 213 by reading and executing a control program 231 stored in a non-volatile memory 230 .

[0018] The movement amount calculation unit 212 of the processor 210 calculates the movement amount of the workpiece 10 in the X-axis direction, the Y-axis direction, and the θ-axis direction, i.e., the rotation angle around the θ-axis, based on the position of the identification target detected from the captured image by the image processing unit 400. The command unit 213 outputs a control signal based on the movement amount calculated by the movement amount calculation unit 212 to the drive control devices 121, 122, and 123.

[0019] The volatile memory 220 is a work memory that can read and write data at high speed during arithmetic processing executed by the processor 210, and includes, for example, a RAM (Random Access Memory). The non-volatile memory 230 stores a control program 231 for implementing various functions of the motion control unit 200, and control data 232 that includes parameters used when executing the control program 231, past detection data, and command data. The non-volatile memory 230 includes, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory), a non-volatile semiconductor memory such as a flash memory, a magnetic disk, or an optical disk.

[0020] The clock 240 includes a real-time clock (RTC), which measures time by counting clock signals from a clock element included in the operation control unit 200, and further synchronizes with the drive control devices 121, 122, and 123, the imaging device 300, and the image processing unit 400.

[0021] The communication interface 250 is an interface that allows the operation control unit 200 to communicate with the drive control devices 121, 122, 123, the imaging device 300, and the image processing unit 400, and includes interfaces that comply with communication standards such as CC-Link IE / field and CC-Link IE / TSN.

[0022] The imaging device 300 is an imaging device that captures images of the workpiece 10 from above the alignment mechanism 100 at regular time intervals, and is, for example, a camera with a resolution sufficient to achieve the alignment accuracy of the alignment system 1. The number of imaging devices 300 is arbitrary, but is determined depending on the number and positions of identification targets used for alignment. FIG. 1 shows a case where two imaging devices 300 are provided. The identification targets may be any targets that indicate the position of the workpiece 10, such as alignment marks on the workpiece 10, corners of the workpiece 10, or corners of the mounting table 101. The identification targets are representative points of the workpiece 10.

[0023] The imaging device 300 has a communication interface for communicating with the drive control devices 121 , 122 , and 123 , the motion control unit 200 , and the image processing unit 400 .

[0024] The image processing unit 400 performs processing to detect an identification target in the captured image acquired from the imaging device 300. When an identification target is detected, the image processing unit 400 outputs the actual coordinates of the identification target to the operation control unit 200. Furthermore, the image processing unit 400 obtains vibration information representing information related to residual vibration of the workpiece end based on the actual coordinates of the identification target.

[0025] 3, the image processing unit 400 includes a processor 410, a volatile memory 420, a non-volatile memory 430, a clock 440, and a communication interface 450. The processor 410, the volatile memory 420, the non-volatile memory 430, the clock 440, and the communication interface 450 are communicatively connected to one another via a bus B2.

[0026] The processor 410 includes, for example, a CPU, and functions as an image acquisition unit 411 and a vibration information calculation unit 414 by reading and executing a control program 431 stored in the nonvolatile memory 430 .

[0027] The image acquisition unit 411 of the processor 410 acquires the image captured by the imaging device 300. The vibration information calculation unit 414 detects the identification target from the captured image, and calculates the amplitude and center of vibration based on the actual coordinates of the identification target.

[0028] The volatile memory 420 is a work memory, such as a RAM, that can read and write data at high speed during arithmetic processing executed by the processor 410. The nonvolatile memory 430 stores a control program 431 for implementing various functions of the image processing unit 400, parameters used when executing the control program 431, and control data 432 that includes past detection data. The nonvolatile memory 430 includes, for example, a nonvolatile semiconductor memory such as an EEPROM or a flash memory, a magnetic disk, or an optical disk.

[0029] The clock 440 includes, for example, a real-time clock (RTC), which measures time by counting clock signals from a clock element included in the image processing unit 400, and further synchronizes with the drive control devices 121, 122, and 123, the motion control unit 200, and the imaging device 300.

[0030] The communication interface 450 is an interface for the image processing unit 400 to communicate with the drive control devices 121, 122, 123, the operation control unit 200, and the imaging device 300, and includes an interface that complies with communication standards such as CC-Link IE / field and CC-Link IE / TSN.

[0031] The setting terminal 500 is a terminal installed with an application program capable of managing the image processing unit 400, and includes, for example, a personal computer. The setting terminal 500 has a function for managing the image processing unit 400, including inputting or changing parameters stored in the non-volatile memory 430 of the image processing unit 400. The communication interface used by the setting terminal 500 to communicate with the image processing unit 400 is any interface corresponding to the interface of the image processing unit 400, and includes, for example, a USB interface or an RS232C interface.

[0032] The operation control unit 200 calculates the amount of movement based on the difference between the actual coordinates of the object to be identified detected by the image processing unit 400 and the target coordinates of the alignment, and outputs a control signal based on the amount of movement to the drive control devices 121, 122, and 123.

[0033] The operation of the alignment system 1 having the above-described configuration will now be described. First, an example of an alignment method based on the position of the identification object, which is the premise, will be described using Figures 4 and 5. Figures 4 and 5 are diagrams explaining the alignment method when the identification object is alignment marks 1001 and 1002 attached to the edge of the workpiece 10.

[0034] The number of alignment marks is arbitrary, and may be one as shown in Fig. 4, or two alignment marks 1001, 1002 may be attached to diagonally opposite ends of the workpiece 10 as shown in Fig. 5. The shape of the alignment marks 1001, 1002 is arbitrary, but a shape that allows the position of the reference point and the rotation angle to be clearly identified is preferable, and for example, a cross mark as shown in Figs.

[0035] When one alignment mark 1001 is used, an image of the imaging range 1300 is acquired by one imaging device 300. When two alignment marks 1001 and 1002 are used and the two alignment marks 1001 and 1002 cannot be imaged in one imaging range 1300, images of imaging ranges 1300 that are offset from each other are acquired by two imaging devices 300. Note that the two imaging ranges 1300 may partially overlap.

[0036] When using one alignment mark 1001 as shown in Figure 4, three pieces of information are used: the coordinates of the reference point of the target alignment mark 1101, the coordinates of the reference point of the alignment mark 1001 on the workpiece 10, and the angular difference Δθ between the target alignment mark 1101 and the alignment mark 1001 based on the rotation axis 1200.

[0037] On the other hand, when two alignment marks 1001 and 1002 are used as shown in Figure 5, three pieces of information are used: the midpoint coordinates of the reference points of the target alignment marks 1101 and 1102, the midpoint coordinates of the reference points of the alignment marks 1001 and 1002 on the workpiece 10, and the angle difference Δθ between the line connecting the target alignment marks 1101 and 1102 and the line connecting the alignment marks 1001 and 1002.

[0038] 4 and 5, the angular difference Δθ is the amount of movement of the movable device 113 around the rotation axis 1200, i.e., the amount of rotation. Therefore, as shown in FIG. 4, the motion control unit 200 calculates the virtual coordinates of the reference point of the virtual mark 1201 after the workpiece 10 has been rotated by an angle Δθ around the rotation axis 1200. Then, the motion control unit 200 calculates the amount of movement ΔX in the X-axis direction and the amount of movement ΔY in the Y-axis direction based on the difference between the virtual coordinates and the target coordinates of the target alignment mark 1101. The command unit 213 of the motion control unit 200 issues commands by transmitting control signals for realizing the movements of Δθ, ΔX, and ΔY thus obtained to the drive control devices 121, 122, and 123.

[0039] As shown in Figure 4, the method of using one alignment mark 1001 can be used when the rotation of the alignment mark 1001 can be clearly determined, such as with a cross mark. On the other hand, as shown in Figure 5, when two alignment marks 1001 and 1002 are used, it is not necessary to detect the rotation of the alignment mark itself, so that even if the alignment mark is circular, for example, the rotation of the workpiece 10 can be detected.

[0040] In this way, the motion control unit 200 calculates Δθ, ΔX, and ΔY based on the coordinates of the reference points of the alignment marks 1001 and 1002 to be identified, and these values ​​are used by the drive control devices 121, 122, and 123 to control the moving devices 111, 112, and 113 to move the workpiece 10. However, since the difference from the target coordinates usually does not fall within the allowable range in one go, the detection of the identification target and the control of the moving devices 111, 112, and 113 are repeatedly executed.

[0041] In such repeated processing, the processing load of searching for the identification target from the image captured by the imaging device 300 is very large. Therefore, the alignment system 1 according to this embodiment reduces the processing load by limiting the range in which the search is performed.

[0042] The details of the process will be explained below with reference to Fig. 6. Fig. 6 is a flowchart of the alignment control process in this embodiment.

[0043] First, the motion control unit 200 issues a command to move the workpiece 10 to a predetermined approximate target position (step S101). Specifically, the motion control unit 200 outputs control signals to the drive control devices 121, 122, and 123 to realize movement in each direction. Then, under the control of the drive control devices 121, 122, and 123 based on the control signals, the drive devices 111, 112, and 113 drive the mounting table 101 on which the workpiece 10 is placed.

[0044] The motion control unit 200 determines whether the in-position signal output by the position sensor of the movable machine 111, 112, 113 has turned ON (step S102). Here, the "in-position signal" means a signal output when positioning is completed. If it is determined that the in-position signal has not turned ON (step S102: No), the determination process of step S102 is repeated until the in-position signal turns ON.

[0045] If it is determined that the in-position signal is ON (step S102: Yes), the operation control unit 200 notifies the image processing unit 400 that the in-position signal is ON. The image processing unit 400 notifies the imaging device 300 that the in-position signal is ON. The imaging device 300 starts capturing images, and the image acquisition unit 411 acquires captured images from the imaging device 300 (step S103). In this embodiment, the imaging device 300 captures images at intervals of 1 ms (millisecond).

[0046] The vibration information calculation unit 414 calculates and stores instantaneous values ​​of the position of the workpiece 10 (step S104). Specifically, the instantaneous values ​​of the coordinates of the alignment mark, which change due to the vibration of the workpiece 10, are calculated and stored. As a simple example, assume that the alignment mark attached to the workpiece 10 vibrates in the X-axis direction due to the vibration of the end of the workpiece 10, and five images are taken to obtain the transition of the alignment mark's position in the X-axis direction, as shown in FIG. 7A. Plotting this results in a waveform representing the transition of the X-axis position versus time T, as shown in FIG. 7B. As shown in FIG. 7B, in the example of FIGS. 7A and 7B, the transition of the alignment mark's position converges within the range of a predetermined first accuracy standard over the five images taken. In this embodiment, the predetermined first accuracy standard is ±50 μm (micrometers). In this embodiment, the target coordinates of the workpiece 10 are predetermined to be (5 mm, 10 mm), which indicates an X coordinate of 5 mm (millimeters) and a Y coordinate of 10 mm. The first accuracy standard range is an example of the first accuracy standard range according to the present disclosure.

[0047] 7A and 7B are roughly drawn, but if the imaging interval is shortened and the vibration trajectory is plotted on the X and Y coordinates, the resulting plot will be dense and will depict a complex trajectory, as shown in Fig. 8. Furthermore, if the trajectory in the X-axis direction shown in Fig. 8 is plotted against time, the graph shown in Fig. 9 will be obtained, and if the trajectory in the Y-axis direction is plotted against time, the graph shown in Fig. 10 will be obtained. By performing the convergence determination described below in each of the X-axis and Y-axis directions, the accuracy of the convergence determination for vibrations that depict complex trajectories can be improved.

[0048] The vibration information calculation unit 414 calculates the vibration waveform in the X-axis direction shown in FIG. 9 and the vibration waveform in the Y-axis direction shown in FIG. 10 based on the capture timing of the captured image and the coordinates of the alignment mark of the workpiece 10 to be identified in the captured image. The vibration information calculation unit 414 processes the calculated vibration waveform to calculate the vibration amplitude and center of vibration of the alignment mark of the workpiece 10. The imaging device 300 captures images at a frame rate of, for example, about 1 ms intervals. The vibration information calculation unit 414 performs edge detection processing or the like on each captured image captured by the imaging device 300 to detect accurate straight lines or curves, thereby identifying the alignment mark and calculating its coordinates.

[0049] The vibration information calculation unit 414 stores the instantaneous values ​​calculated in step S104 and determines whether the amplitude calculated from the series of instantaneous values ​​is within a predetermined first accuracy standard (step S105). Specifically, the vibration information calculation unit 414 determines whether the amplitude of the vibration in the X-axis direction and the amplitude of the vibration in the Y-axis direction are both within the first accuracy standard. In step S105, the vibration information calculation unit 414 determines whether the amplitude of the vibration in the X-axis direction is within a range of ±50 μm and whether the amplitude of the vibration in the Y-axis direction is within a range of ±50 μm. Note that the vibration in the X-axis direction and the vibration in the Y-axis direction are each an example of a vibration directional component according to the present disclosure.

[0050] If it is determined that at least one of the amplitude of vibration in the X-axis direction and the amplitude of vibration in the Y-axis direction is not within the range of a predetermined first accuracy standard, in other words, not within the range of ±50 μm (step S105: No), the process returns to step S103 and is repeated until the amplitude is within ±50 μm in both the X-axis and Y-axis directions.

[0051] If it is determined that both the amplitude of vibration in the X-axis direction and the amplitude of vibration in the Y-axis direction are within the range of a predetermined first accuracy standard, in other words, within a range of ±50 μm (step S105: Yes), the vibration information calculation unit 414 determines the center of vibration (step S106). The vibration information calculation unit 414 determines the center of vibration in the X-axis direction and the center of vibration in the Y-axis direction. The vibration information calculation unit 414 determines the coordinate of the center of the vibration waveform determined, for example, the vibration waveform shown in FIG. 9. The coordinate of the center of the vibration waveform can also be said to indicate the coordinate indicating the center of the distance over which the position of the workpiece 10 transitions due to vibration. Specifically, the vibration information calculation unit 414 determines the center of vibration by, for example, calculating the average value of two points: a positive peak where the instantaneous value changes from small to large and a negative peak where the instantaneous value changes from large to small, or by calculating the average value of a total of four points: two positive peaks and two negative peaks of the instantaneous value. The accuracy of calculating the vibration center is improved by averaging the total of four points compared to averaging the total of two points. Note that these two points or the total of four points may or may not be consecutive.

[0052] The vibration information calculation unit 414 determines whether the center of vibration calculated in step S106 is within a predetermined second accuracy standard range from the target coordinates (step S107). The range of the second accuracy standard is narrower than the range of the first accuracy standard. In this embodiment, the range of the second accuracy standard is ±25 μm. By narrowing the range of the accuracy standard, the accuracy of determining vibration convergence is improved. The vibration information calculation unit 414 determines whether the center of vibration in the X-axis direction and the center of vibration in the Y-axis direction are both within the range of the second accuracy standard. For example, the vibration information calculation unit 414 determines whether the center of vibration in the X-axis direction calculated in step S106 is within a range of 5 mm ±25 μm, and whether the center of vibration in the Y-axis direction is within a range of 10 mm ±25 μm.

[0053] If it is determined that at least one of the center of vibration in the X-axis direction and the center of vibration in the Y-axis direction is not within the range of the predetermined second accuracy standard (step S107: No), the vibration information calculation unit 414 outputs the actual coordinates of the identification target to the motion control unit 200. The command unit 213 outputs a command to correct the position of the alignment mechanism 100 (step S108). Specifically, the command unit 213 calculates the position difference between the target coordinates and the current coordinates, and outputs a control signal to the drive control devices 121, 122, and 123 to move the mounting table 101 by the position difference. This process is the same as step S101. After step S108, the process returns to step S102.

[0054] If it is determined that both the center of vibration in the X-axis direction and the center of vibration in the Y-axis direction are within the range of a predetermined second accuracy standard (step S107: Yes), the vibration information calculation unit 414 determines whether the amplitude of the X-axis component and the amplitude of the Y-axis component of the vibration represented by a series of instantaneous values ​​are within the range of the second accuracy standard (step S109). If it is determined that the amplitude of the X-axis component and the amplitude of the Y-axis component are within the range of the second accuracy standard (step S109: Yes), the vibration information calculation unit 414 outputs an authorization signal to the setting terminal 500 (step S112). Here, the authorization signal is, for example, a signal that permits the application of some processing to the workpiece 10. For example, if the workpiece 10 is a substrate and this alignment device is part of a bonding device that bonds semiconductor chips to the workpiece 10, the signal indicates that the substrate, which is the workpiece 10, has been aligned and the vibration of the workpiece 10 has subsided, and therefore it is OK to proceed to the bonding operation. After step S112, the alignment control process ends.

[0055] If it is determined that at least one of the amplitudes of the X-axis component and the Y-axis component of the vibration is not within the second accuracy standard (step S109: No), the image processing unit 400 performs a convergence waiting process, waiting until the amplitude falls within the second accuracy standard range. Specifically, the image acquisition unit 411 acquires a captured image from the imaging device 300 (step S110). The vibration information calculation unit 414 calculates and stores instantaneous values ​​based on the captured image acquired by the image acquisition unit 411 (step S111). The process of calculating the instantaneous values ​​in step S111 is the same as the process of calculating the instantaneous values ​​in step S104. After step S111, the process returns to step S109.

[0056] As described above, the alignment system 1 according to this embodiment includes an image processing unit 400 that detects an identification target from an image of the workpiece 10 having the identification target, determines the vibration amplitude and center of the workpiece 10, and determines convergence. The motion control unit 200 controls the moving devices 111, 112, and 113 that move the workpiece 10 based on the convergence determination performed by the image processing unit 400. If the vibration information calculation unit 414 in the image processing unit 400 determines that the determined amplitude is within a predetermined first accuracy standard, it determines whether the determined center of vibration is within a predetermined second accuracy standard. If the vibration information calculation unit 414 determines that the determined center of vibration is not within the predetermined second accuracy standard, it outputs the actual coordinates of the identification target to the motion control unit 200. The command unit 213 executes a command to correct the position of the alignment mechanism 100. This determines the appropriate timing for correcting the position of the alignment mechanism 100, thereby reducing unnecessary waiting time for vibration convergence. Furthermore, when the amplitude of the vibration falls within the range of the second accuracy standard, machining of the workpiece 10 is permitted. This allows the appropriate timing for starting the next machining to be determined, and makes it possible to reduce the unnecessary waiting time for the vibration to converge. Note that the second accuracy standard used in step S107 and the second accuracy standard used in step S109 may be different.

[0057] (Variation of First Embodiment) Note that the vibration information calculation unit 414 determines the center of vibration by calculating the average of two points, a positive peak and a negative peak, of the instantaneous value, or the average of a total of four points, two positive peaks and two negative peaks, of the instantaneous value. However, the present disclosure is not limited to this. For example, a method using the envelope signal of each vibration component is also conceivable. In this case, for example, the vibration information calculation unit 414 acquires an upper extremum group representing a group of three or more points with maximum amplitudes, and calculates the constant Ca based on a decay curve equation y = Aexp(-Bx) + Ca that represents the decay curve equation and the least squares method. Note that in the decay curve equation, A represents the amount of decay, B represents a constant representing the decay rate, and Ca represents the lower limit of decay. Furthermore, the vibration information calculation unit 414 acquires a lower extremum group representing a group of three or more points with minimum amplitudes, and calculates the constant Cb based on an amplification curve equation y = -Aexp(-Bx) + Cb that represents the amplification curve equation and the least squares method. In the amplification curve formula, A is the amplification amount, B is a constant representing the amplification rate, and Cb is the upper limit of amplification. The average value of the constant Ca representing the lower limit of attenuation and the constant Cb representing the upper limit of amplification is calculated as the oscillation center. This improves the accuracy of the oscillation center calculation.

[0058] Furthermore, the first accuracy standard value was 50 μm, and the second accuracy standard value was 25 μm, which is 1 / 2 of the first accuracy standard value, but the present disclosure is not limited to this. The second accuracy standard value was simply 0.5 times the first accuracy standard, but it may also be (1 / √2) times the first accuracy standard. If convergence determination is performed with an accuracy of ±50 μm in each of the X and Y axes, under worst-case conditions, the combination of the orthogonal X and Y axis directions will result in an error of √2, or 50√2 μm. For this reason, it is advisable to set the accuracy standard to 1 / √2 in advance.

[0059] The second accuracy reference value may be determined based on past operational results. Specifically, whether convergence is faster as is or movement based on a correction command may be determined based on a processing time based on past operational results. The first accuracy reference value and the second accuracy reference value may be any reference value as long as they achieve the effects of the present disclosure.

[0060] Furthermore, although the imaging device 300 captures images at intervals of 1 ms, the interval is not limited to 1 ms, and the imaging device 300 may capture images at intervals of, for example, 3 ms or 5 ms.

[0061] Furthermore, after the peak of the coordinate instantaneous value falls within the accuracy standard range, it may again fall outside the accuracy standard range. Therefore, for instantaneous values ​​outside the accuracy standard range, the specified time after reaching the accuracy standard range may be determined based on the swing-back rate of the instantaneous value. Specifically, the value obtained by multiplying the period of the waveform representing the instantaneous value by the number of cycles may be calculated and set as the specified monitoring time. Furthermore, for example, if the point representing the positive peak of the instantaneous value and the point representing the negative peak swing back every two or three cycles, it may be determined that convergence has occurred if the point representing the peak every three cycles is within the accuracy standard range. Here, swing-back refers to the magnitude of the swing between the point representing the positive peak of the instantaneous value and the point representing the negative peak of the instantaneous value changing from large to small, or vice versa.

[0062] Furthermore, the shock that causes vibration depends on the jerk, which is the first derivative of acceleration. To prevent vibration, it is necessary to control the robot to move smoothly to a specified position while suppressing the jerk. For this reason, vibration may be prevented by generating a command curve that suppresses jerk using a high-order curve or an S-shaped acceleration / deceleration curve, and sending a command to the drive control devices 121, 122, and 123 based on the generated command curve.

[0063] Second Embodiment A second embodiment for carrying out the present disclosure will now be described with reference to the drawings, in which the same or corresponding parts are designated by the same reference numerals.

[0064] The overall configuration and the hardware configuration of each part of the alignment system 1 according to the second embodiment are the same as those of the first embodiment. The alignment system 1 according to the second embodiment differs from the first embodiment in that a high-speed alignment control process, which will be described later, is performed instead of the alignment control process shown in Fig. 6. The following description of the second embodiment will focus on the differences from the first embodiment.

[0065] The high-speed alignment control process will be described below with reference to Fig. 11. Fig. 11 is a flowchart of the high-speed alignment control process in the second embodiment.

[0066] First, the motion control unit 200 issues a command to move the workpiece 10 to a predetermined approximate target position (step S201). Step S201 is the same as step S101 of the alignment control process in the first embodiment.

[0067] After step S201, the imaging device 300 starts capturing images, and the image acquisition unit 411 acquires the captured image from the imaging device 300 (step S202). Step S202 is similar to step S103 in the first embodiment. However, the second embodiment differs from the first embodiment in that the process of step S102 in the first embodiment, in other words, the process of determining whether the in-position signal has been turned ON, is omitted. Since the process of step S202 is performed without waiting for the in-position signal, this leads to faster overall alignment control processing.

[0068] After step S202, the vibration information calculation unit 414 determines the vibration locus and determines the vibration waveform based on the determined vibration locus, as in the first embodiment. The vibration information calculation unit 414 determines the center of the vibration (step S203). Step S203 is the same as step S106 in the first embodiment.

[0069] The vibration information calculation unit 414 determines whether the center of vibration obtained in step S203 is within a range of a predetermined second accuracy standard (step S204). In the first embodiment, the vibration information calculation unit 414 first performs amplitude determination processing (step S105). However, in the second embodiment, the vibration information calculation unit 414 obtains the center of vibration and performs vibration center determination processing (step S204) before the amplitude determination processing. Note that step S204 is the same as step S107 in the first embodiment.

[0070] If it is determined that the center of vibration is not within the range of the second accuracy standard (step S204: No), the process returns to step S202 after issuing a correction command in step S205. In the first embodiment, the process of determining the amplitude (step S105) is performed before issuing the correction command (step S108). However, in the second embodiment, the process of determining the correction command is performed based only on the process of determining the center of vibration (step S205) without first performing the amplitude determination process. This allows the retry operation associated with the correction command to be expedited without waiting for the amplitude to converge.

[0071] If it is determined that the center of vibration is within the range of the second accuracy standard (step S204: Yes), after acquiring a captured image in step S206, the process goes through a process of calculating an instantaneous value in step S207, and then to execution of an amplitude determination process (step S208). Step S206 is the same as step S110 in the first embodiment, and step S207 is the same as step S111 in the first embodiment. Furthermore, step S208 is the same as step S109 in the first embodiment.

[0072] If it is determined that the amplitude is not within the second accuracy standard range (step S208: No), the process returns to step S206. If it is determined that the amplitude is within the second accuracy standard range (step S208: Yes), the high-speed alignment control process ends after the process of step S209. Note that step S209 is the same as step S112 in the first embodiment.

[0073] As described above, in the high-speed alignment control process of the second embodiment, the retry operation associated with the correction command is executed based only on the determination of the center of vibration, without going through the determination of the amplitude of vibration. Furthermore, in the high-speed alignment control process of the second embodiment, the determination of whether the in-position signal is ON as in the first embodiment is omitted, and therefore there is no need to wait for the in-position signal. For these reasons, the high-speed alignment control process of the second embodiment reduces unnecessary waiting time during the retry operation compared to the alignment control process of the first embodiment, and can achieve even faster overall alignment control.

[0074] (Variations of Embodiments 1 and 2) The alignment system 1 may be part of a processing device that processes the workpiece 10. For example, as shown in FIG. 12 , the alignment system 1 may be incorporated into a bonding device that bonds a chip 610 to the workpiece 10. The bonding device includes, for example, a chip moving mechanism 600 that moves the chip 610. After an enabling signal indicating that it is OK to proceed to the bonding operation is output to the setting terminal 500, the setting terminal 500 may send a command to the chip moving mechanism 600 to bond the chip 610 to the workpiece 10. Note that the enabling signal may also be output directly from the operation control unit 200 to the chip moving mechanism 600.

[0075] Various embodiments and modifications are possible without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to illustrate the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0076] 1 Alignment system, 10 Work, 100 Alignment mechanism, 101 Placement table, 111, 112, 113 Driving equipment, 121, 122, 123 Driving control device, 200 Motion control unit, 210 Processor, 212 Movement amount calculation unit, 213 Command unit, 220 Volatile memory, 230 Non-volatile memory, 231 Control program, 232 Control data, 240 Clock, 250 Communication interface, 300 Imaging device, 400 Image processing unit, 410 Processor, 411 Image acquisition unit, 414 Vibration information calculation unit, 420 Volatile memory, 430 Non-volatile memory, 431 Control program, 432 Control data, 440 Clock, 450 Communication interface, 500 Setting terminal, 600 Chip moving mechanism, 610 Chip, 1001, 1002 Alignment marks, 1101, 1102 target alignment marks, 1200 rotation axis, 1201 virtual mark, 1300 imaging range.

Claims

1. An alignment system for aligning a workpiece, comprising: an image processing unit configured to determine a center of vibration of a representative point of the workpiece based on a captured image of the workpiece and determine whether the determined center is within a range of an accuracy standard of the representative point; and an operation control unit configured to control a driving device that moves the workpiece, wherein the operation control unit controls the driving device based on a result determined by the image processing unit.

2. The alignment system according to claim 1, wherein the image processing unit further determines an amplitude of vibration of the representative point of the workpiece, and determines whether the determined amplitude is within a range of an accuracy standard and whether the center is within a range of the accuracy standard of the representative point, and the operation control unit controls the driving device based on a result determined by the image processing unit.

3. The alignment system according to claim 2, wherein when it is determined that the determined amplitude is within a range of the accuracy standard of the amplitude and the determined center is not within a range of the accuracy standard of the representative point, the operation control unit controls the driving device to move the workpiece to a predetermined position.

4. The alignment system according to claim 2, wherein when it is determined that the determined amplitude is within a range of the accuracy standard of the amplitude and the determined center is within a range of the accuracy standard of the representative point, the image processing unit outputs a permission signal indicating that the image processing unit may shift to an operation after positioning of the workpiece.

5. The alignment system according to any one of claims 2 to 4, wherein the image processing unit decomposes the vibration of the representative point into two vibration direction components, and further determines an amplitude of one vibration direction component obtained by the decomposition and an amplitude of the other vibration direction component obtained by the decomposition.

6. The alignment system according to claim 5, wherein the image processing unit determines whether the amplitude of the one vibration direction component and the amplitude of the other vibration direction component are each within a range of the accuracy standard of the amplitude.

7. The alignment system according to any one of claims 1 to 6, wherein the image processing unit decomposes the vibration of the representative point into two vibration direction components, and determines a center of one vibration direction component obtained by the decomposition and a center of the other vibration direction component obtained by the decomposition.

8. The alignment system according to claim 7, wherein the image processing unit determines whether the center of the one vibration direction component and the center of the other vibration direction component are each within the range of the accuracy standard of the representative point.

9. An alignment method comprising: determining, based on a captured image of a workpiece, the center of vibration of a representative point of the workpiece and determining whether the obtained center is within a range of an accuracy standard of the representative point determined in advance; and controlling a drive device that moves the workpiece based on the result of the determination.

10. A program for causing a computer to execute a process of determining, based on a captured image of a workpiece, the center of vibration of a representative point of the workpiece and determining whether the obtained center is within a range of an accuracy standard of the representative point determined in advance, and controlling a drive device that moves the workpiece based on the result of the determination.

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