Alignment method

Abstract

To provide an alignment method capable of preventing an alignment error.SOLUTION: An alignment method 1000 includes a target storage step 1100 for storing an arbitrary pattern formed in a device area as a target, in a reference image acquired by imaging a first workpiece, a reference luminance storage step 1200 for storing the luminance of the reference image as reference luminance, an alignment image acquisition step 1300 for acquiring an alignment image by imaging a second workpiece different from the first workpiece to which the target storage step 1100 is executed, a light quantity adjustment step 1400 for adjusting the quantity of light with which the second workpiece is irradiated so that the luminance of the alignment image approaches the reference luminance, an adjusted alignment image acquisition step 1500 for acquiring an adjusted alignment image by imaging the second workpiece again, and a target detection step 1600 for detecting the target from the adjusted alignment image by image processing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an alignment method. [Background technology]

[0002] In processing devices such as cutting devices and laser processing devices, alignment is performed using pattern matching to align the planned processing line of the workpiece with the processing unit. Patent Document 1 discloses a cutting device that, when it is determined that the cutting groove is not appropriate based on the processing conditions input by the input means and the state of the cutting groove imaged by the imaging means, determines whether the cutting groove is appropriate or not while adjusting the light amount of the light irradiator of the imaging means within a predetermined range, and when it is determined that the cutting groove is appropriate, changes the light amount imaged when it is determined that it is appropriate as a corrected light amount. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5389580 Summary of the Invention [Problem to be solved by the invention]

[0004] When a film is laminated on the side of the workpiece where the device is formed, if the thickness of the film is not uniform, the brightness of the image obtained will differ depending on the location even if the workpiece is irradiated with light under the same light intensity conditions. Therefore, when aligning the workpiece during mass production, the target cannot be detected due to the difference in image brightness, and an alignment error may occur. Conventionally, when an alignment error occurs, the operator manually adjusts the light intensity and performs the alignment operation.

[0005] The present invention has been made in view of the above, and an object of the present invention is to provide an alignment method capable of preventing alignment errors. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the alignment method of the present invention is an alignment method for a workpiece having a plurality of device regions formed on one side thereof and partitioned by a plurality of planned division lines, and is characterized by comprising: a target storage step of storing an arbitrary pattern formed in the device region in a reference image acquired by imaging a first workpiece, as a target; a reference brightness storage step of storing the brightness of the reference image as a reference brightness; an alignment image acquisition step of imaging a second workpiece different from the first workpiece on which the target storage step was performed, to acquire an alignment image; a light intensity adjustment step of adjusting the amount of light irradiated to the second workpiece so that the brightness of the alignment image is close to the reference brightness; an adjusted alignment image acquisition step of imaging the second workpiece again after the light intensity adjustment step, to acquire an adjusted alignment image; and a target detection step of detecting the target from the adjusted alignment image by image processing.

[0007] In the alignment method, the brightness of the alignment image and the light intensity conditions when the adjusted alignment image was obtained are linked and registered in a database, and the light intensity adjustment step may refer to the database to adjust the light intensity to the light intensity conditions corresponding to the brightness of the alignment image.

[0008] The alignment method may further comprise a division line detection step of specifying the position of the division line based on the target.

[0009] In the alignment method, the target detection step may further include an orientation rotation step of detecting the target in at least two locations among the multiple device areas of the workpiece held by a holding table moving in the X-axis direction, rotating the holding table so that the angles of the targets detected in the at least two locations are aligned, and aligning the orientation of a processing feed unit that processes and feeds the holding table in the X direction with the planned division line. Effect of the Invention

[0010] The present invention has the effect of preventing alignment errors. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a flowchart showing the processing procedure of the alignment method. [Diagram 2] FIG. 2 is a perspective view showing an example of a workpiece used in the alignment method. [Diagram 3] FIG. 3 is a perspective view showing an example of a problem of the workpiece shown in FIG. [Figure 4] FIG. 4 is a perspective view showing a configuration example of a processing device according to an embodiment. [Diagram 5] FIG. 5 is a schematic front view showing an example of the configuration of a light source of the imaging unit. [Figure 6] FIG. 6 is a diagram for explaining the target storage step and the reference luminance storage step shown in FIG. [Figure 7] FIG. 7 is a diagram for explaining the alignment image obtaining step shown in FIG. [Figure 8] FIG. 8 is a diagram showing an example of the relationship between the luminance of an alignment image and light quantity conditions. [Figure 9] FIG. 9 is a diagram for explaining the adjusted alignment image acquisition step shown in FIG. [Figure 10] FIG. 10 is a diagram for explaining example images of the same type of workpiece captured under the same light quantity conditions. [Figure 11]FIG. 11 is a flowchart showing a processing procedure according to a modified alignment method. [Figure 12] FIG. 12 is a diagram for explaining a modification of the alignment method shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the contents described in the following embodiment. Furthermore, the components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the configurations described below can be appropriately combined. Furthermore, various omissions, substitutions, or modifications of the configurations can be made without departing from the gist of the present invention.

[0013] In the embodiment described below, an XYZ Cartesian coordinate system is set, and the positional relationship of each part is described with reference to this XYZ Cartesian coordinate system. One direction in a horizontal plane is the X-axis direction, a direction perpendicular to the X-axis direction in the horizontal plane is the Y-axis direction, and a direction perpendicular to both the X-axis direction and the Y-axis direction is the Z-axis direction. The XY plane including the X-axis and Y-axis is parallel to the horizontal plane. The Z-axis direction perpendicular to the XY plane is the vertical direction.

[0014] [Embodiment] An alignment method according to an embodiment will be described with reference to the drawings. FIG. 1 is a flowchart showing a processing procedure of the alignment method. FIG. 2 is a perspective view showing an example of a workpiece used in the alignment method. FIG. 3 is a perspective view showing an example of a task of the workpiece shown in FIG. 2. FIG. 4 is a perspective view showing an example of the configuration of a processing device according to an embodiment. FIG. 5 is a schematic front view showing an example of the configuration of a light source of an imaging unit.

[0015] 1, an alignment method 1000 according to an embodiment includes a target storage step 1100, a reference brightness storage step 1200, an alignment image acquisition step 1300, a light amount adjustment step 1400, an adjusted alignment image acquisition step 1500, a target detection step 1600, and a planned division line detection step 1700. The alignment method 1000 is an alignment method for a workpiece having a plurality of device regions partitioned by a plurality of planned division lines formed on one surface thereof, and is realized by a processing device 1 described later. In this embodiment, the alignment includes the processing device 1 described later capturing an image of the workpiece with an imaging unit and detecting each planned division line.

[0016] A workpiece to be aligned by the alignment method 1000 according to the embodiment will be described with reference to the drawings. As shown in FIG. 2 and FIG. 3, the workpiece 200 is a disk-shaped semiconductor workpiece, an optical device workpiece, or other workpiece having a substrate 211 made of silicon (Si), sapphire (Al2O3), gallium arsenide (GaAs), silicon carbide (SiC), or the like, and is a silicon workpiece in the embodiment. The workpiece 200 has a plurality of division lines 217 set in a lattice pattern on the surface 212 of the substrate 211, and device regions 220 formed in each region partitioned by the division lines 217. The workpiece 200 has a plurality of device regions 220, and devices 218 are formed in each of the plurality of device regions 220. The devices 218 include thick bumps, lenses, or the like on the surface. In the present embodiment, the surface 212 of the substrate 211 is one surface of the workpiece 200, and the back surface 213 is the other surface of the workpiece 200.

[0017] The workpiece 200 is formed with a film 214 covering the entire surface 212. The film 214 is a protective film formed by applying a protective film agent made of a non-polymerized resin to the entire surface 212 of the workpiece 200. For example, when the workpiece 200 has a film 214 formed on the surface 212, if there is unevenness in the film, thickness, and components of the film 214, there is a possibility that a region 241-1 where the film 214 is thick will be generated as shown in FIG. 3. In this case, even if multiple workpieces 200 of the same type are irradiated with light under the same light amount conditions and imaged, the brightness of the image will vary. In the conventional alignment method, during alignment during mass production of the workpieces 200, the target cannot be detected due to the difference in brightness, and an alignment error occurs. Then, when an alignment error occurs, in the conventional alignment method, the operator needs to manually operate the device to adjust the light amount and perform the alignment operation. In this embodiment, an alignment method 1000 that can prevent alignment errors is provided. Note that the brightness of the image means the brightness value of the image.

[0018] (Processing equipment) As shown in Fig. 4, the processing device 1 includes a holding table 10, a processing unit 20, an imaging unit 30, a moving unit 40, and a control unit 100. The holding table 10 holds the workpiece 200 by suction on a holding surface 11. The processing unit 20 cuts the workpiece 200 held by the holding table 10 with a cutting blade 21 attached to a spindle 22. The imaging unit 30 captures an image of the workpiece 200 held by the holding table 10. The moving unit 40 moves the holding table 10 and the processing unit 20 relatively. The control unit 100 controls each component of the processing device 1. The control unit 100 is electrically connected to a storage unit 150.

[0019] The moving unit 40 includes at least an X-axis moving unit 41 which moves the holding table 10 in the X-axis direction parallel to the horizontal direction for processing, a Y-axis moving unit 42 which indexes and moves the processing unit 20 and the imaging unit 30 in the Y-axis direction parallel to the horizontal direction and perpendicular to the X-axis direction, and a Z-axis moving unit 43 which cuts and moves the processing unit 20 and the imaging unit 30 in the Z-axis direction. The X-axis moving unit 41, the Y-axis moving unit 42, and the Z-axis moving unit 43 are each formed of, for example, a ball screw, a nut, a pulse motor, or the like.

[0020] The X-axis moving unit 41 moves the holding table 10 in the X-axis direction, thereby performing processing feed between the holding table 10 and the processing unit 20 relative to each other along the X-axis direction. The Y-axis moving unit 42 moves the processing unit 20 in the Y-axis direction, which is the indexing feed direction, thereby performing indexing feed between the holding table 10 and the processing unit 20 relative to each other along the Y-axis direction. The Z-axis moving unit 43 moves the processing unit 20 in the Z-axis direction, which is the cutting feed direction, thereby performing cutting feed between the holding table 10 and the processing unit 20 relative to each other along the Z-axis direction. The X-axis moving unit 41 is a processing feed unit.

[0021] The holding table 10 has a disk-like shape and a holding surface 11 for holding the workpiece 200, which is formed from porous ceramics or the like. The holding table 10 is provided so as to be movable in the X-axis direction by an X-axis moving unit 41 and rotatable about an axis parallel to the Z-axis direction by a rotary drive source (not shown). The holding surface 11 of the holding table 10 is connected to a vacuum suction source (not shown). The workpiece 200 integrated with an annular frame 208 is placed on the holding surface 11 of the holding table 10 via a sheet 207, and the holding surface 11 is sucked by the vacuum suction source, thereby suction-holding the workpiece 200 integrated with the frame 208.

[0022] The holding table 10 is rotated around an axis parallel to the Z-axis direction by a rotation unit 13. The rotation unit 13 is supported by an X-axis direction moving plate 14. The rotation unit 13 and the holding table 10 are moved in the X-axis direction by an X-axis moving unit 41 of a moving unit 40 via the X-axis direction moving plate 14.

[0023] The processing unit 20 is a unit in which a cutting blade 21 for cutting a workpiece 200 held on the holding table 10 is rotatably mounted. The processing unit 20 is capable of positioning the cutting blade 21 at any position on the holding surface 11 of the holding table 10 by a Y-axis moving unit 42 and a Z-axis moving unit 43. The processing unit 20 includes the cutting blade 21 and a spindle 22. The cutting blade 21 is fixed to the tip of the spindle 22 and rotates around an axis parallel to the Y-axis direction as the spindle 22 rotates. The spindle 22 is rotatably supported by the spindle housing around an axis parallel to the Y-axis direction with the tip exposed to the outside from the spindle housing, and is accommodated in the spindle housing.

[0024] The imaging unit 30 is an electron microscope equipped with a CCD (Charge-Coupled Device) camera or the like that captures an image of the surface of the workpiece 200 held on the holding surface 11 of the holding table 10, and is used for both alignment and kerf checking. Here, in the case of alignment, the processing device 1 detects the area to be cut based on the image information acquired by the imaging unit 30, and positions the processing operation by the processing unit 20. In addition, in the case of kerf checking, the processing device 1 positions the cut groove of the cut workpiece 200 at the imaging position of the imaging unit 30 to capture the cut groove, generate image information, and generate cut groove data by image processing. The imaging unit 30 is fixed to the processing unit 20 so as to move integrally with the processing unit 20. As shown in FIG. 5, the imaging unit 30 includes a light source 31 that irradiates illumination light onto the surface of the workpiece 200 held on the holding surface 11 of the holding table 10. The light source 31 has an epi-illumination light source 32 that illuminates the workpiece 200 from directly above, and an oblique light source 33 that illuminates the workpiece 200 from an oblique direction. In this embodiment, the light source 31 is a light-emitting element such as an LED (Light Emitting Diode), but may also be an optical fiber that propagates light emitted by a light-emitting element such as an LED.

[0025] The control unit 100 includes an arithmetic processing device such as a CPU (Central Processing Unit), a storage device such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and an input / output interface device. The control unit 100 is a computer that can execute programs and the like for controlling the above-mentioned components in accordance with the alignment, processing, and the like performed by the processing device 1 using such devices.

[0026] The control unit 100 controls the operation of each mechanism (X-axis moving unit 41, Y-axis moving unit 42, Z-axis moving unit 43) that drives the processing device 1, the processing unit 20, the imaging unit 30, etc. The control unit 100 controls each part of the processing device 1 and realizes processing by the processing device 1. The control unit 100 controls each part of the processing device 1 including the holding table 10, the processing unit 20, the imaging unit 30, etc., for example, by executing a program, and realizes alignment, processing, etc. of the workpiece 200. The control unit 100 controls the processing unit 20 to execute alignment, processing for cutting the workpiece 200, etc., while the workpiece 200 is held on the holding surface 11 of the holding table 10.

[0027] The control unit 100 executes a program to realize a target storage step 1100, a reference brightness storage step 1200, an alignment image acquisition step 1300, a light amount adjustment step 1400, an adjusted alignment image acquisition step 1500, a target detection step 1600, and a division line detection step 1700 (see FIG. 1). In this embodiment, the multiple workpieces 200 include a first workpiece for which the alignment target setting mode has been implemented, and a second workpiece different from the first workpiece. The control unit 100 displays an operation panel on the display device in the alignment target setting mode during data setting when performing full automation processing of the processing device 1. The control unit 100 displays an image of the surface 212 of the workpiece 200 captured by the imaging unit 30 over the entire surface, almost the entire surface, or a part of the surface, on the operation panel, and displays multiple operation keys for performing the control functions of the mode in an image display area in which the image is displayed. The control unit 100 stores, as a target, an arbitrary pattern of the device 218 formed in the device area 220 in the displayed reference image. The arbitrary pattern includes a unique key pattern in the device 218 that does not have a similar pattern in its surroundings.

[0028] The processing device 1 further includes a storage unit 150. The storage unit 150 stores programs for implementing functions such as various processes executed by the control unit 100, data used in the processes by the programs, and the like. The storage unit 150 can be implemented by a hard disk drive (HDD), a semiconductor memory, or the like. The storage unit 150 may also be used as a temporary work area when a processor included in the control unit 100 executes instructions written in the programs. The storage unit 150 may be an external storage device of the processing device 1.

[0029] The storage unit 150 stores various data such as a target 151, a reference brightness 152, an alignment image 153, an adjusted alignment image 154, and a light quantity condition 155 in association with the workpiece 200. The target 151 includes information on an alignment target during data setting when performing full automation processing of the processing device 1 in a reference image 500 acquired by imaging the first workpiece. The reference brightness 152 includes information indicating the brightness of the reference image 500. The alignment image 153 includes an image of the second workpiece imaged for alignment. The adjusted alignment image 154 includes an image of the second workpiece imaged by adjusting the amount of light irradiated to the second workpiece so as to be close to the reference brightness 152 of the reference image 500. The light quantity condition 155 includes information indicating the light quantity of the imaging unit 30 when the image was captured. In this embodiment, the brightness of the alignment image 153 and the light quantity condition 155 are linked in the storage unit 150, and the storage unit 150 functions as a database.

[0030] The processing device 1 controls the position and orientation of the alignment, processing, etc. of the workpiece 200 held on the holding table 10 by moving the holding table 10 and the processing unit 20 relatively with the X-axis movement unit 41, the Y-axis movement unit 42, and the Z-axis movement unit 43. With the workpiece 200 held on the holding surface 11 of the holding table 10, the processing device 1 performs alignment and cuts the workpiece 200 with the cutting blade 21 while supplying liquid to the cutting location.

[0031] The processing unit 20 included in the processing device 1 is not limited to a cutting unit that uses a cutting blade to cut the substrate 211. For example, the processing unit 20 may be a grinding unit that uses a grinding wheel or the like to grind the substrate 211, a polishing unit that uses a polishing pad or the like to polish the substrate 211, or a laser processing unit that irradiates a laser beam onto the substrate 211 to perform laser processing.

[0032] The above describes an example of the configuration of the processing device 1 according to the embodiment. Note that the above configuration described with reference to Fig. 4 is merely an example, and the configuration of the processing device 1 according to the embodiment is not limited to this example. The functional configuration of the processing device 1 according to the embodiment can be flexibly modified according to the specifications and operation.

[0033] (Alignment method) Next, an alignment method 1000 executed by the processing device 1 according to the embodiment will be described. FIG. 6 is a diagram for explaining the target storage step and the reference brightness storage step shown in FIG. 1. FIG. 7 is a diagram for explaining the alignment image acquisition step shown in FIG. 1. FIG. 8 is a diagram showing an example of the relationship between the brightness of the alignment image and the light amount condition. FIG. 9 is a diagram for explaining the adjusted alignment image acquisition step shown in FIG. 1. FIGS. 6, 7, and 9 each show an image of a part of the workpiece 200 captured by the imaging unit 30.

[0034] In this embodiment, the processing device 1 is placed on the holding surface 11 of the holding table 10 with the surface 212 of the workpiece 200 facing upward, and the holding table 10 suction-holds the workpiece 200 on the holding surface 11. The processing device 1 performs alignment for aligning the cutting blade 21 with an area corresponding to the planned division line 217 of the workpiece 200 based on an image acquired by the imaging unit 30. The alignment method 1000 shown in Fig. 1 is realized by the control unit 100 of the processing device 1 executing a program.

[0035] First, the processing device 1 executes a target storage step 1100. The target storage step 1100 is a step of storing an arbitrary pattern formed in the device region 220 as a target in the storage unit 150 in a reference image acquired by the imaging unit 30 capturing an image of the workpiece 200 (first workpiece). In an example shown in FIG. 6, the processing device 1 acquires a reference image 500 showing a portion where the division lines 217 of the workpiece 200 intersect with each other by the imaging unit 30, and stores a pattern including a key pattern of the device 218 and a corner of the device 218 in the reference image 500 as a target 151 in the storage unit 150. Note that the brightness of the reference image 500 shown in FIG. 6 is 180, and the light quantity condition 155 at the time of capturing the image is set to 50% of the light quantity of the incident light source 32 and 50% of the light quantity of the oblique light source 33. The processing device 1 associates information such as the size of the target 151, the distance from the target 151 to the planned division line 217, and the reference image 500 with the target 151. The target 151 may be an image of only a characteristic symbol. When the processing device 1 finishes the target storage step 1100, the processing device 1 advances the step to the next reference brightness storage step 1200 shown in FIG.

[0036] The processing device 1 executes a reference brightness storage step 1200. The reference brightness storage step 1200 is a step of storing the brightness of the reference image 500 used in the target storage step 1100 as the reference brightness 152 in the storage unit 150. For example, the processing device 1 obtains the reference brightness 152 based on the sum or average value of the brightness (for example, 0 to 256) of each pixel of the reference image 500. The processing device 1 stores the reference brightness 152 in the storage unit 150, and associates the light quantity condition 155 when the reference image 500 is captured with the reference brightness 152. For example, if the light quantity condition 155 when the reference image 500 is captured is 50% incident light and 50% oblique light, the processing device 1 associates information indicating the light quantity condition 155 with the reference brightness 152. When the reference brightness storage step 1200 is completed, the processing device 1 advances the step to the next alignment image acquisition step 1300 shown in FIG. 1.

[0037] The processing device 1 executes an alignment image acquisition step 1300. The alignment image acquisition step 1300 is a step of acquiring an alignment image 153 shown in FIG. 7 by imaging a work 200 (second work) different from the work 200 (first work) for which the target storage step 1100 has been performed. For example, the processing device 1 acquires an alignment image 153 by imaging the work 200 with the imaging unit 30 under the same light quantity condition 155 as the reference image 500 while holding the other work 200 on the holding table 10. In this case, even if the processing device 1 images the work 200 under the same light quantity condition 155 as the reference image 500, there are cases in which the brightness of the reference image 500 does not reach the reference brightness 152 due to individual differences of the work 200. In an example shown in FIG. 7, the brightness of the alignment image 153 is 150, which is lower than the reference brightness 152, and the light quantity condition 155 at the time of imaging is the same as the light quantity condition 155 of the reference image 500. When the alignment image acquisition step 1300 is completed, the processing device 1 advances the step to the next light amount adjustment step 1400 shown in FIG.

[0038] The processing device 1 executes a light amount adjustment step 1400. The light amount adjustment step 1400 is a step of adjusting the light amount of the light source 31 that irradiates the workpiece 200 (second workpiece) so that the luminance of the alignment image 153 approaches the reference luminance 152. If the luminance of the alignment image 153 is low, the luminance may be low due to the influence of the film 214 of the workpiece 200, and the luminance of the reference image 500 will not match unless the workpiece 200 is irradiated with a larger amount of light. For this reason, the processing device 1 obtains the luminance of the acquired alignment image 153, and obtains the illumination conditions of the incident light source 32 and the oblique light source 33 so that the luminance approaches the reference luminance 152.

[0039] In this embodiment, the processing device 1 stores a database 600 shown in FIG. 8 in the storage unit 150. The database 160 is capable of identifying the relationship between the luminance of the alignment image 153 and the light quantity condition 155 for acquiring the adjusted alignment image. The database 160 indicates the ratio of the light quantity of the incident light source 32 and the oblique light source 33 of the light source 31 as the light quantity condition 155. The database 160 registers the light quantity condition 155 adjusted for each luminance of the alignment image 153 to approach the luminance of the reference image 510 using experiments, machine learning, simulations, and the like. For example, when the luminance of the alignment image 153 is 100, the processing device 1 extracts information from the database 160 for adjusting the light quantity condition 155 so as to increase the light quantity of the incident light source 32 by 70% and the light quantity of the oblique light source 33 by 25%. For example, when the brightness of the alignment image 153 is 180, the processing device 1 extracts information from the database 160 for adjusting the light intensity condition 155 so as to increase the light intensity of the incident light source 32 by 30% and the light intensity of the oblique light source 33 by 25%.

[0040] For example, when the processing device 1 acquires the alignment image 153 shown in FIG. 7, in the light amount adjustment step 1400, the light amount condition 155 of the light source 31 is adjusted so that the reference luminance 152 of the reference image 500 and the luminance of the image to be captured are the same 180. When the light amount condition 155 when acquiring the reference image 500 and the alignment image 153 is 50% for the light amount of the incident light source 32 and 25% for the light amount of the oblique light source 33, the processing device 1 sets the light amount condition 155 to 80% for the incident light source 32 and 50% for the light amount of the oblique light source 33 based on the database 160. That is, the processing device 1 adjusts the light amount condition 155 for acquiring the adjusted alignment image 154 by increasing the light amount of the incident light source 32 by 30% and increasing the light amount of the oblique light source 33 by 25%. When the light amount adjustment step 1400 is completed, the processing device 1 advances the step to the next adjusted alignment image acquisition step 1500 shown in FIG. 1.

[0041] The processing device 1 executes an adjusted alignment image acquisition step 1500. The adjusted alignment image acquisition step 1500 is a step of acquiring an adjusted alignment image 154 shown in FIG. 9 by imaging the work 200 (second work) in a state where the work 200 is illuminated with the light amount adjusted in the light amount adjustment step 1400. For example, the processing device 1 acquires an adjusted alignment image 154 by imaging the work 200 with the imaging unit 30 under the light amount condition 155 adjusted in the light amount adjustment step 1400 in a state where another work 200 is held on the holding table 10. In an example shown in FIG. 9, the processing device 1 acquires an adjusted alignment image 154 whose luminance is the same as the luminance 180 of the reference image 500, thereby making it easier to detect the target 151 set in the reference image 500. When the adjusted alignment image acquisition step 1500 is completed, the processing device 1 advances the step to the next target detection step 1600 shown in FIG. 1.

[0042] The processing device 1 executes a target detection step 1600. The target detection step 1600 is a step of detecting the target 151 from the adjusted alignment image 154 by image processing. For example, the processing device 1 performs pattern matching between the target 151 stored in the storage unit 150 and the adjusted alignment image 154, and detects the target 151 corresponding to the planned division line 217 of the workpiece 200 from the adjusted alignment image 154. After storing the detected target 151 in the storage unit 150, the processing device 1 proceeds to the next step of detecting the planned division line 1700.

[0043] The processing device 1 executes a planned division line detection step 1700. The planned division line detection step 1700 is a step of identifying the position of the planned division line 217 of the workpiece 200 based on the targets detected in the target detection step 1600. For example, the processing device 1 detects the planned division line 217 of the workpiece 200 based on the multiple targets 151 detected in the target detection step 1600 and the distance from the targets 151 to the planned division line 217. When the planned division line detection step 1700 is completed, the processing device 1 ends the alignment method 1000 shown in FIG. 1.

[0044] 1 may add a step of determining whether or not the luminance of the acquired alignment image 153 is a luminance that requires light amount adjustment after alignment image acquisition step 1300. In this case, alignment method 1000 proceeds to light amount adjustment step 1400 if it is determined that the luminance of alignment image 153 is a luminance that requires light amount adjustment. Then, alignment method 1000 proceeds to target detection step 1600 if it is determined that the luminance of alignment image 153 is not a luminance that requires light amount adjustment.

[0045] (Example of alignment method) Fig. 10 is a diagram for explaining an example of images captured of the same type of workpiece under the same light quantity condition. In the example shown in Fig. 10, the processing device 1 stores the target 151 with the reference luminance 152 of the reference image 500 being 180, and the light quantity condition 155 is assumed to be such that the light quantity of the incident light source 32 is 50% and the light quantity of the oblique light source 33 is 50%.

[0046] 10, when the brightness of the alignment image 153-1 is 160 due to the thickness of the film 214 of the workpiece 200, the processing device 1 adjusts the light quantity condition 155 based on the database 600 so that the brightness becomes 180, the same as the reference brightness 152 of the reference image 500. Also, when the brightness of the alignment image 153-2 is 140 due to the thickness of the film 214 of the workpiece 200, as shown in scene 2002 of FIG. 10, the processing device 1 adjusts the light quantity condition 155 based on the database 600 so that the brightness becomes 180, the same as the reference brightness 152 of the reference image 500. As a result, when the alignment method 1000 executed by the processing device 1 acquires an alignment image 153 with a luminance different from the reference luminance 152, it can adjust the light quantity condition of the light source 31 so that the luminance approaches the reference luminance 152, so that even if there is variation in the thickness of the film 214 of the workpiece 200, it can accurately detect the target 151 from the adjusted alignment image 154. As a result, the alignment method 1000 can prevent the occurrence of an alignment error caused by the failure to detect the target 151 due to a difference in luminance during alignment during mass production of the workpiece 200 by the processing device 1.

[0047] In the light amount adjustment step 1400, the alignment method 1000 can adjust the light amount of the light source 31 to a light amount condition 155 according to the luminance of the alignment image 153. As a result, the alignment method 1000 can adjust the luminance of the alignment image 153 to the reference luminance 152, so that even if there is variation in the thickness of the film 214 of the workpiece 200, the target 151 can be detected more accurately from the adjusted alignment image 154.

[0048] The alignment method 1000 can identify the position of the planned dividing line of the workpiece 200 based on the detected target 151. As a result, the alignment method 1000 can accurately detect the target 151, and therefore can accurately detect the planned dividing line 217 from the target 151.

[0049] (Modification of Alignment Method) Fig. 11 is a flow chart showing a processing procedure according to a modified example of the alignment method, and Fig. 12 is a diagram for explaining the modified example of the alignment method shown in Fig. 11.

[0050] As shown in Fig. 11, an alignment method 1000 according to the modified embodiment includes the above-mentioned target storage step 1100, reference brightness storage step 1200, alignment image acquisition step 1300, light amount adjustment step 1400, adjusted alignment image acquisition step 1500, target detection step 1600, and orientation rotation step 1800. Note that in the alignment method 1000 shown in Fig. 11, steps that are the same as those in the alignment method 1000 shown in Fig. 1 are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0051] In this embodiment, the processing device 1 is placed on the holding surface 11 of the holding table 10 with the surface 212 of the workpiece 200 facing upward, and the holding table 10 suction-holds the workpiece 200 on the holding surface 11. The processing device 1 performs alignment for aligning the cutting blade 21 with an area corresponding to the planned division line 217 of the workpiece 200 based on an image acquired by the imaging unit 30. An alignment method 1000 shown in Fig. 11 is realized by causing the control unit 100 of the processing device 1 to execute a program.

[0052] The processing device 1 sequentially executes the above-mentioned target storage step 1100, reference brightness storage step 1200, alignment image acquisition step 1300, light amount adjustment step 1400, and adjusted alignment image acquisition step 1500. Then, when the adjusted alignment image acquisition step 1500 is completed, the processing device 1 executes a target detection step 1600. In the target detection step 1600, targets 151 are detected in at least two locations among a plurality of device regions 220 of the workpiece 200 held by the holding table 10 moving in the X-axis direction in the processing device 1. In the adjusted alignment image 154, the processing device 1 detects targets 151 from a plurality of device regions 220 along the planned division line 217 parallel to the X-axis direction along which the holding table 10 moves. When the processing device 1 stores the detected plurality of targets 151 in the storage unit 150, the processing device 1 advances to the next step of direction rotation step 1800.

[0053] The processing device 1 executes an orientation rotation step 1800. The orientation rotation step 1800 is a step of rotating the holding table 10 so that the angles of the targets 151 detected at at least two locations are aligned, and aligning the orientation of the X-axis moving unit 41 (processing feed unit) that processes and feeds the holding table 10 in the X-axis direction with the planned division line 217 of the workpiece 200. For example, as shown in a scene 2101 of FIG. 12, when the X-axis operation direction 3000 and the direction 3100 along the planned division line 217 are misaligned in the adjusted alignment image 154, the processing device 1 rotates the holding table 10 so that the angles of the targets 151 in different device regions 220 are aligned. The X-axis operation direction 3000 is the direction in which the processing device 1 processes and feeds the holding table 10 in the X-axis direction. The direction 3100 is parallel to the street direction connecting the two targets 151. As shown in scene 2102 of Fig. 12, the processing apparatus 1 rotates the holding table 10 so that the X-axis operation direction 3000 and the X-axis operation direction 3000 do not intersect but are parallel to each other. When the orientation rotation step 1800 is completed, the processing apparatus 1 ends the alignment method 1000 shown in Fig. 11.

[0054] The processing device 1 can adjust the light quantity condition 155 based on the database 600 so that the brightness is the same as the reference brightness 152 of the reference image 500 even if the brightness of each alignment image 153 differs depending on the thickness of the film 214 of the workpiece 200, etc. As a result, when the alignment method 1000 executed by the processing device 1 acquires an alignment image 153 with a brightness different from the reference brightness 152, the light quantity condition of the light source 31 can be adjusted so that the brightness approaches the reference brightness 152, so that the target 151 can be accurately detected from the adjusted alignment image 154 even if the thickness of the film 214 of the workpiece 200 varies. As a result, the alignment method 1000 can prevent the occurrence of an alignment error due to the inability to detect the target 151 due to the difference in brightness during alignment during mass production of the workpiece 200 by the processing device 1.

[0055] Furthermore, alignment method 1000 rotates holding table 10 so that the angles of targets 151 detected at at least two locations in adjusted alignment image 154 are aligned, and can align the orientation of X-axis moving unit 41, which feeds holding table 10 for processing in the X-axis direction, with the planned division line 217 of workpiece 200. As a result, alignment method 1000 can accurately detect multiple targets 151, and therefore can improve the accuracy of adjusting the θ degree of workpiece 200 so that streets on workpiece 200 can be cut straight based on the multiple targets 151.

[0056] In the above embodiment, the alignment method 1000 includes a target storage step 1100, a reference brightness storage step 1200, an alignment image acquisition step 1300, a light amount adjustment step 1400, an adjusted alignment image acquisition step 1500, a target detection step 1600, and a planned division line detection step 1700 or a direction rotation step 1800. However, the alignment method 1000 may include only the target storage step 1100, the reference brightness storage step 1200, the alignment image acquisition step 1300, the light amount adjustment step 1400, the adjusted alignment image acquisition step 1500, and the target detection step 1600. For example, the alignment method 1000 may include a target storage step 1100, a reference brightness storage step 1200, an alignment image acquisition step 1300, a light intensity adjustment step 1400, an adjusted alignment image acquisition step 1500, a target detection step 1600, a planned division line detection step 1700, and an orientation rotation step 1800.

[0057] In the above embodiment, the processing device 1 that executes the alignment method 1000 has been described as being implemented by a cutting device that cuts the workpiece 200, but is not limited thereto. For example, the processing device 1 may be implemented by various devices that perform alignment, such as a laser beam irradiation device, a grinding device, a polishing device, a plasma etching device, or a cutting tool device. [Explanation of symbols]

[0058] 1 Processing equipment 10 Holding table 11 Holding surface 20 Processing Unit 21 Cutting blade 30 Imaging unit 31 Light source 32 Epi-illumination source 33 Oblique light source 41 X-axis moving unit 42 Y-axis moving unit 43 Z-axis moving unit 100 Control Unit 150 Storage section 151 Target 152 Reference Luminance 153 Alignment Image 154 Adjusted alignment image 155 Light Conditions 200 Work 207 seats 208 frames 211 Substrate 212 Surface 213 Back side 214 Membrane 217 Division Line 218 Devices 220 Device Area 1000 Alignment Methods 1100 Target Memory Step 1200 reference luminance memory steps 1300 Alignment image acquisition steps 1400 light adjustment steps 1500 Adjusted alignment image acquisition steps 1600 target detection steps 1700 Steps for detecting division lines 1800 orientation rotation steps

Claims

1. A method for aligning a workpiece having a plurality of device regions formed on one surface thereof and partitioned by a plurality of planned division lines, comprising the steps of: a target storage step of storing, as a target, an arbitrary pattern formed in the device region in a reference image acquired by imaging the first workpiece; a reference luminance storage step of storing the luminance of the reference image as a reference luminance; an alignment image acquisition step of acquiring an alignment image by imaging a second workpiece different from the first workpiece on which the target storage step has been performed; a light amount adjusting step of adjusting the amount of light irradiated onto the second workpiece so that the luminance of the alignment image approaches the reference luminance; an adjusted alignment image acquisition step of acquiring an adjusted alignment image by imaging the second work again after the light amount adjustment step; a target detection step of detecting the target from the adjusted alignment image by image processing; An alignment method comprising:

2. The brightness of the alignment image is associated with the light quantity conditions when the adjusted alignment image was acquired, and the associated brightness is registered in a database; The light amount adjustment step includes:

2. The alignment method according to claim 1, further comprising the step of: referring to said database, adjusting said light amount to said light amount condition according to the luminance of said alignment image.

3. 2. The alignment method according to claim 1, further comprising a dividing line detection step of specifying the position of the dividing line based on the target.

4. The target detection step detects the target in at least two locations among the plurality of device areas of the workpiece held by a holding table moving in the X-axis direction; 2. The alignment method according to claim 1, further comprising an orientation rotation step of rotating the holding table so that the angles of the targets detected at at least two locations are aligned, and aligning the orientation of a processing feed unit that processes and feeds the holding table in the X direction with the intended division line.

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