Processing method and measuring method

Abstract

To provide a measuring method capable of measuring the height of a target part even when there is an uneven structure on the surface of a measuring object.SOLUTION: A measurement method for measuring a height of a surface of a measurement object includes an image forming step of imaging a target region of the measurement object under a plurality of conditions different in height of an imaging unit and forming a plurality of images, a height recording step of recording a height of the imaging unit at the time when an image in focus in an effective region, which is a part of an imaging range of the imaging unit, is obtained, and a height calculating step of calculating a height of a target portion of the measurement object on the basis of the height of the imaging unit recorded in the height recording step and a distance at which the imaging unit is in focus.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a measurement method for measuring the height of an object to be measured, and a processing method for processing a workpiece using this measurement method. [Background technology]

[0002] There is a known technique for cutting a groove of a predetermined depth into the surface of a plate-like workpiece such as a semiconductor wafer using a cutting tool called a cutting blade (see, for example, Patent Document 1). With this technique, the height of the surface of the workpiece is measured, and the cutting blade is cut to an appropriate depth based on the measured surface height, thereby realizing a groove of a more accurate depth.

[0003] A common method for measuring the height of the surface of a workpiece is a laser distance measurement method that uses a laser beam reflected from the surface of the object, but in recent years, a method that uses the focusing of an imaging unit already provided in the processing device has also been proposed (see, for example, Patent Document 2). With this method, the height of the object's surface is calculated based on the height of the imaging unit provided in the processing device when the focal point of the imaging unit is aligned with the surface of the object, so there is no need to newly provide a laser distance meter or the like to the processing device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-353170 [Patent Document 2] Japanese Patent Publication No. 2020-116685 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the surface of a workpiece may have a large uneven structure, such as a bump electrode. In such a case, when the surface of the workpiece is imaged with an imaging unit, the imaging unit may focus on the uneven structure, making it impossible to properly calculate the height of the surface to be processed.

[0006] Therefore, an object of the present invention is to provide a measurement method that can measure the height of a target part even if the surface of the object to be measured has an uneven structure, and a processing method that processes a workpiece using this measurement method. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a processing method for processing a portion of a first surface of a workpiece having a textured structure on the first surface, the processing method including: an image formation step for capturing images of a target area of ​​the workpiece under a plurality of conditions with different heights of an imaging unit to form a plurality of images; a height recording step for recording the height of the imaging unit when the image is obtained in focus in an effective area that is a portion of the imaging range of the imaging unit including a lens; and a processing step for processing the portion of the first surface of the workpiece to a target depth using conditions set based on the height of the imaging unit recorded in the height recording step.

[0008] The workpiece has bump electrodes as the uneven structure, and the processing method may further include an effective area setting step of setting the effective area so that an area where the bump electrodes are not present is captured in the effective area when the target area of ​​the workpiece is imaged. Preferably, the processing method further includes a position designating step of designating the position of the target area of ​​the workpiece.

[0009] According to another aspect of the present invention, there is provided a measurement method for measuring the height of a target portion of a measurement object using an imaging unit including a lens, the measurement method including: an image formation step for imaging a target area of ​​the measurement object under a plurality of conditions with different heights of the imaging unit to form a plurality of images; a height recording step for recording the height of the imaging unit when the image that is in focus in an effective area that is a part of the imaging range of the imaging unit is obtained; and a height calculation step for calculating the height of the target portion of the measurement object based on the height of the imaging unit recorded in the height recording step and the distance at which the imaging unit is in focus.

[0010] The object to be measured may have bump electrodes on its surface, and the measurement method may further include an effective area setting step of setting the effective area so that an area where the bump electrodes are not present is captured in the effective area when the object to be measured is imaged. Preferably, the measurement method further includes a position designation step of designating the position of the object to be measured. [Effects of the Invention]

[0011] In a measurement method according to one aspect of the present invention, the target area of ​​the object to be measured is imaged under a plurality of conditions with different heights of the imaging unit, a plurality of images are formed, and the height of the imaging unit is recorded when an image that is in focus in the effective area, which is part of the imaging range of the imaging unit, is obtained.Therefore, even in a situation where the target area of ​​the object to be measured includes an uneven structure and the uneven structure is captured in each image, the height of the target part can be calculated using an appropriately set effective area.

[0012] In other words, according to the measurement method of one aspect of the present invention, it is possible to measure the height of a target portion even if the surface of the measurement object has an uneven structure. Furthermore, since the processing method of another aspect of the present invention includes the same procedure as the measurement method of one aspect of the present invention, it is possible to process the workpiece to a target depth. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view schematically showing the structure of a cutting device. [Figure 2] FIG. 2 is a perspective view schematically showing the structure of the workpiece. [Figure 3] FIG. 3 is a flowchart showing the flow of the processing method. [Figure 4] FIG. 4 is a flowchart showing the flow of the measurement method. [Figure 5] FIG. 5 is a plan view of a workpiece for explaining an example of a method for specifying the position of a target region to be imaged. [Figure 6] FIG. 6 is a diagram showing the imaging range of the imaging unit. [Figure 7] FIG. 7 is a perspective view that schematically shows how a workpiece is machined. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view showing a schematic structure of a cutting device (processing device) 2 used in a processing method including a measurement method of this embodiment. In Fig. 1, some elements are expressed as functional blocks. Furthermore, the X-axis (front-rear axis), Y-axis (left-right axis), and Z-axis (vertical axis) used in the following description are perpendicular to one another.

[0015] As shown in Fig. 1, the cutting device 2 includes a base 4 that supports various elements. A storage space 4a is provided at a corner of the base 4, with the upper end open to the top surface of the base 4. A cassette table 6 that is raised and lowered by a lifting mechanism (not shown) is disposed within the storage space 4a. A cassette 8 that can accommodate a plurality of plate-shaped workpieces (measurement objects) 11 is placed on the top surface of the cassette table 6. For ease of explanation, only the outline of the cassette 8 is shown in Fig. 1.

[0016] 2 is a perspective view schematically showing the structure of workpiece 11. Workpiece 11 is typically a disk-shaped wafer made of a semiconductor such as silicon (Si), and has a circular first surface (front surface) 11a and a circular second surface (back surface) 11b opposite to first surface 11a.

[0017] The workpiece 11 also has an annular side surface 11c connecting the end of the first surface 11a and the end of the second surface 11b, and a cutout portion 11d is provided in part of this side surface 11c. The cutout portion 11d is called a notch or the like and indicates the crystal orientation of the semiconductor that constitutes the workpiece 11. Note that an orientation flat or the like may be formed as the cutout portion 11d instead of a notch.

[0018] The first surface 11a of the workpiece 11 is divided into a plurality of small regions by a plurality of linear processing lines (streets) 13 that intersect with each other, and a device 15 such as an IC (Integrated Circuit) is formed in each small region. Furthermore, each device 15 has a plurality of bump electrodes (concave-convex structure) 17 that function as terminals (electrodes) and are arranged so as to be exposed on the first surface 11a of the workpiece 11. The bump electrodes 17 are formed of, for example, a conductive material such as solder.

[0019] A tape (dicing tape) 21 having a diameter larger than that of the workpiece 11 is attached to the second surface 11b of the workpiece 11. A ring-shaped frame 23 is fixed to the outer edge of the tape 21 so as to surround the workpiece 11. In this way, the workpiece 11 is accommodated in the cassette 8 while being supported by the frame 23 via the tape 21.

[0020] In this embodiment, a disk-shaped wafer made of a semiconductor such as silicon is exemplified as the workpiece 11, but the material, shape, structure, size, etc. of the workpiece 11 are not limited to this. For example, a substrate made of other materials such as semiconductors, ceramics, resins, and metals may also be used as the workpiece 11.

[0021] Similarly, the type, number, shape, structure, size, arrangement, etc. of the device 15 are not limited to the above-mentioned embodiments. The device 15 may not be formed on the workpiece 11. Furthermore, the workpiece 11 may be provided with another uneven structure instead of or in addition to the bump electrode 17. Furthermore, the cutout portion 11d may not be provided on the workpiece 11. Furthermore, the workpiece 11 does not necessarily have to be supported on the frame 23 via the tape 21.

[0022] At a position adjacent to cassette table 6 along the Y-axis, an accommodation space 4b is formed on the top surface of base 4, with its upper end open and long in the direction along the X-axis. A ball screw type chuck table moving mechanism (processing feed mechanism) 10 is disposed within accommodation space 4b. Chuck table moving mechanism 10 includes a screw shaft (not shown) constituting a ball screw, a rotational drive source (not shown) such as a motor connected to the end of the screw shaft, and an X-axis moving table (not shown) provided with a nut portion coupled to the screw shaft, and moves the X-axis moving table along the X-axis.

[0023] The top of the X-axis moving table is covered by a plate-shaped cover 10a. Attached to both ends of cover 10a in the direction along the X-axis are accordion-shaped covers 10b that expand and contract in accordance with the movement of the X-axis moving table and cover 10a. A chuck table (holding table) 12 for holding workpiece 11 is arranged above the X-axis moving table so as to be exposed from cover 10a.

[0024] The chuck table 12 is connected to a rotary drive source (not shown) such as a motor, and rotates around a rotation axis along the Z axis by the power of this rotary drive source. The chuck table 12 is also moved along the X axis together with the X-axis moving table and cover 10a by the chuck table moving mechanism 10 described above (processing feed).

[0025] The chuck table 12 includes a disk-shaped frame 14 made of a metal such as stainless steel. A recess with a circular opening at the top end is provided on the top surface of the frame 14. A disk-shaped holding plate 16 that matches the shape of the recess is fitted into the recess of the frame 14. Four clamps 18 are arranged around the periphery of the frame 14 to secure an annular frame 23 that supports the workpiece 11.

[0026] The holding plate 16 is made of a porous plate-like material such as ceramics, and holds the workpiece 11 on its upper surface (holding surface) 16a. The upper surface 16a of the holding plate 16 is configured to be generally parallel to the X-axis and Y-axis when the holding plate 16 is fitted into the recess of the frame 14. In other words, the chuck table 12 can rotate around a rotation axis that is generally perpendicular to the upper surface 16a of the holding plate 16.

[0027] A suction source (not shown) is connected to the bottom of the recess of the frame 14 via a flow path (not shown), a valve (not shown), etc. Therefore, when the valve is opened, negative pressure from the suction source acts on the upper surface 16a of the holding plate 16 through the flow path, etc. As the suction source, for example, a vacuum pump or the like that combines an air supply source and an ejector is used. However, a rotary pump or the like may also be used as the suction source.

[0028] Above the accommodation space 4b, one or more transport mechanisms (not shown) are arranged that can transport the above-mentioned workpiece 11 (frame 23) to the chuck table 12, etc. The transport mechanism, for example, carries the workpiece 11 out of the cassette 8 and carries it into the chuck table 12 positioned in a front carry-in / out area close to the cassette 8 (cassette table 6). The workpiece 11 is placed on the upper surface 16a of the chuck table 12, for example, with the first surface 11a facing upward (and the second surface 11b facing downward).

[0029] A cantilevered support structure 20 is disposed adjacent to the accommodation space 4b along the Y axis. A cutting unit movement mechanism (indexing feed mechanism, cutting feed mechanism) 22 is disposed above the support structure 20. This cutting unit movement mechanism 22 has a pair of Y-axis guide rails 24 that are fixed to the front of the support structure 20 and extend along the Y axis.

[0030] A Y-axis moving plate 26, which constitutes the cutting unit moving mechanism 22, is attached to the Y-axis guide rail 24 in a manner that allows it to slide along the Y-axis. A nut portion (not shown) that constitutes a ball screw is provided on the back side of the Y-axis moving plate 26, and a long screw shaft 28 that is rotatable along the Y-axis is connected to this nut portion via a number of small balls.

[0031] A rotary drive source (not shown), such as a motor, is connected to the end of the screw shaft 28. Therefore, when the screw shaft 28 is rotated by the power of the rotary drive source, the Y-axis moving plate 26 moves along the longitudinal direction of the Y-axis guide rail 24, i.e., along the Y-axis. A pair of Z-axis guide rails 30 that are long along the Z-axis are fixed to the front of the Y-axis moving plate 26. A Z-axis moving plate 32 is attached to the pair of Z-axis guide rails 30 in a manner that allows it to slide along the Z-axis.

[0032] A nut portion (not shown) constituting a ball screw is provided on the back side of Z-axis moving plate 32, and a long screw shaft 34 extending along the Z axis is rotatably connected to this nut portion via a plurality of small balls. A rotational drive source 36 such as a motor is connected to the end of screw shaft 34. Therefore, when screw shaft 34 is rotated by the power of rotational drive source 36, Z-axis moving plate 32 moves along the longitudinal direction of Z-axis guide rail 30, i.e., along the Z axis.

[0033] A cutting unit (processing unit) 38 is fixed to the lower part of the Z-axis moving plate 32. The cutting unit 38 has a cylindrical spindle housing. A part of a cylindrical spindle 40 (see FIG. 7), which serves as a rotation axis along the Y-axis, is housed in the internal space of the spindle housing.

[0034] The tip of the spindle 40 is exposed to the outside of the spindle housing. Attached to the tip of the spindle 40 is an annular cutting blade (grinding tool for processing) 42 (see FIG. 7), which is obtained by, for example, solidifying abrasive grains such as diamond with a binder such as resin. Meanwhile, a rotational drive source (not shown), such as a motor, is connected to the base end of the spindle 40. Therefore, when the spindle 40 is rotated by the power of this rotational drive source, the cutting blade 42 rotates around a rotation axis along the Y-axis.

[0035] Additionally, an imaging unit (camera) 44 configured to be able to capture images from above of the workpiece 11, etc. supported by the chuck table 12, is fixed to the lower part of the Z-axis moving plate 32. This imaging unit 44 is moved along the Y-axis and Z-axis together with the cutting unit 38 by the cutting unit moving mechanism 22.

[0036] The imaging unit 44 includes an imaging element (two-dimensional optical sensor) such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor, and an imaging lens, and is configured to receive light incident from below along the Z axis. By moving the imaging unit 44 along the Z axis using the cutting unit moving mechanism 22, the focus of the imaging unit 44 is adjusted to the workpiece 11, etc. However, the structure, arrangement, etc. of the imaging unit 44 are not limited to this.

[0037] A storage space 4c is formed at a position opposite to the storage space 4a with respect to the storage space 4b. A cleaning unit 46 for cleaning the workpiece 11 and the like after processing is disposed within the storage space 4c. A controller (control unit) 48 is connected to elements such as the chuck table moving mechanism 10, the transport mechanism, the cutting unit moving mechanism 22, the cutting unit 38, the imaging unit 44, and the cleaning unit 46.

[0038] The controller 48 is configured by, for example, a computer including a processing device 50 and a storage device 52, and controls the operation of each element of the above-mentioned cutting device 2 so as to properly process the workpiece 11. The processing device 50 is typically a CPU (Central Processing Unit) and performs various arithmetic processing required to control the above-mentioned elements.

[0039] The storage device 52 includes, for example, a main storage device such as a DRAM (Dynamic Random Access Memory) and an auxiliary storage device such as a hard disk drive, a flash memory, etc. The functions of the controller 48 are realized, for example, by the processing device 50 operating in accordance with software (programs, etc.) stored in the storage device 52.

[0040] An input / output device (input device, output device) 54 that serves as a user interface is connected to the controller 48. The input / output device 54 is, for example, a touch screen, and inputs instructions from an operator to the controller 48. Furthermore, the input / output device 54 outputs (displays, in the case of a touch screen) information related to the cutting device 2 based on instructions from the controller 48, etc., in a format that can be recognized by the operator.

[0041] In this embodiment, the input / output device 54 has both an input function and an output function, but an input device having an input function and an output device having an output function may each be connected to the controller 48. Examples of input devices that can be used include a keyboard, a mouse, and a microphone. Examples of output devices that can be used include a display device such as a liquid crystal display, a speaker that can communicate information by sound, and an indicator light that can communicate information by the color of light or the state of light emission (on, blinking, off, etc.).

[0042] Fig. 3 is a flowchart showing the flow of a processing method including a measurement method of this embodiment, and Fig. 4 is a flowchart showing the flow of a measurement method within the processing method. In the processing method of the workpiece 11 according to this embodiment, first, the workpiece 11 is held by the chuck table 12 (holding step ST11).

[0043] Specifically, for example, the workpiece 11 is carried out of the cassette 8 by the transport mechanism and placed on the upper surface 16a of the chuck table 12 so that the first surface 11a of the workpiece 11 faces upward (the second surface 11b faces downward). Next, the valve is opened, and negative pressure from the suction source acts on the workpiece 11 (tape 21) from the upper surface 16a of the holding plate 16. As a result, the workpiece 11 is sucked and held by the chuck table 12. At this time, the annular frame 23 supporting the workpiece 11 is fixed by the clamp 18.

[0044] Next, the height of a part of the area to be processed on the first surface 11a of the workpiece 11 (hereinafter referred to as "target portion") is measured using the imaging unit 44 (measurement step ST12, measurement method). FIG. 4 shows a detailed flow of the height measurement. As shown in FIG. 4, when measuring the height of the "target portion", first, the position of the target area to be imaged by the imaging unit 44 is specified on the workpiece 11 (position specification step ST121).

[0045] Here, the target area is an area for measuring the height of the "target portion," and therefore needs to be specified so as to include at least the "target portion." Fig. 5 is a plan view of the workpiece 11 for explaining an example of a method for specifying the position of the target area to be imaged. In this embodiment, the position (X, Y) of the target area to be imaged by the imaging unit 44 is specified by X and Y coordinates with the center O of the first surface 11a of the workpiece 11 as the reference (origin).

[0046] 5 shows the imaging ranges (field of view, target area) 44a of the imaging unit 44, each centered on a position (a, 0), a position (-a, 0), a position (0, b), and a position (0, -b). The imaging range 44a at each position coincides with the target area to be imaged. In this embodiment, two locations symmetrical with respect to the X axis and two locations symmetrical with respect to the Y axis are designated as the positions of the target area. Information about the designated positions is recorded in the storage device 52 of the controller 48.

[0047] It should be noted that the specific method for specifying the position of the target area to be imaged is not limited to this embodiment. For example, the number of specified positions may be three or less, or five or more. Furthermore, instead of the center O, the side surface 11c (outer edge) or the cutout portion 11d of the workpiece 11 may be used as the reference (origin). Furthermore, using a characteristic pattern (key pattern) present on each device 15 as the reference, a position at a predetermined distance from this pattern may be specified as the position of the target area.

[0048] 4, the position of the target area may be specified by the operator each time the height of the "target portion" is measured, or may be specified in advance based on the design information of the workpiece 11 and recorded in the controller 48 (storage device 52), etc. In other words, the position of the target area may be specified for each workpiece 11, or may be specified collectively for multiple workpieces 11 having the same design information or multiple workpieces 11 in the same lot.

[0049] In the latter case where the position of the target area is specified in advance, it is not necessary to specify the position of the target area again each time the height of the "target portion" is measured. In other words, in the procedure for measuring the height of the "target portion" (measurement step ST12, measurement method), the procedure for specifying the position of this target area (position specification step ST121) may be omitted.

[0050] After the position of the target area to be imaged is specified, a part of the imaging range 44a of the imaging unit 44 is set as the effective area (effective area setting step ST122). This effective area is the area within the imaging range 44a in which the "target part" is captured when the workpiece 11 is imaged at each position.

[0051] Fig. 6 is a diagram showing an imaging range 44a of the imaging unit 44. The imaging range 44a shown in Fig. 6 includes the line to be processed 13, the device 15, and the bump electrode 17 that are present on the first surface 11a side of the workpiece 11. For example, information necessary for accurately forming a groove of a target depth in the line to be processed 13 is the height of the first surface 11a at the line to be processed 13.

[0052] Therefore, in this embodiment, a part or all of the area in the imaging range 44a that captures the line to be processed 13, which is the "target portion," is set as the effective area 44b, as shown in Fig. 6. Here, the size of the effective area 44b is set arbitrarily within a range that allows appropriate determination later as to whether or not the effective area 44b is in focus, and is typically about 10% to 80% of the area of ​​the imaging range 44a, and preferably about 15% to 50% of the area of ​​the imaging range 44a.

[0053] In this embodiment, the difference in elevation between the line to be processed 13 and the device 15 is sufficiently small, and the area in which the line to be processed 13 is captured and a part of the area in which the device 15 is captured are set as the effective area 44b. Of course, the entire area in which the device 15 is captured may be set as the effective area 44b, or only the area in which the line to be processed 13 is captured may be set as the effective area 44b.

[0054] In other words, the effective area 44b in this embodiment is set so that when an image of the target area of ​​the workpiece 11 is captured, at least an area where no bump electrodes 17 exist is captured in the effective area 44b. In this way, the "target portion" may include, in addition to the area to be processed, an area that can be considered to be at substantially the same height as this area. Information regarding the set effective area 44b is recorded in the storage device 52 of the controller 48.

[0055] Furthermore, in this embodiment, a part of the imaging range 44a of the imaging unit 44 is set as the effective area, but any area (position, coordinates) on the first surface 11a of the workpiece 11 may be set as the effective area. In other words, the procedure of setting the effective area 44b (effective area setting step ST122) includes the case where any area on the first surface 11a of the workpiece 11 is set as the effective area 44b.

[0056] Furthermore, the effective area 44b may be set by the operator each time the height of the "target portion" is measured, or may be set in advance based on the design information of the workpiece 11 and recorded in the controller 48 (storage device 52) or the like. In other words, the effective area 44b may be set for each workpiece 11, or may be set collectively for a plurality of workpieces 11 having the same design information or a plurality of workpieces 11 in the same lot.

[0057] In the latter case where the effective area 44b is set in advance, it is not necessary to specify the effective area 44b anew each time the height of the "target portion" is measured. In other words, in the procedure for measuring the height of the "target portion" (measurement step ST12, measurement method), the procedure for setting this effective area 44b (effective area setting step ST122) may be omitted.

[0058] After the effective area 44b is set, measurement of the height of the "target portion" is started. That is, the target area of ​​the workpiece 11 is imaged under a plurality of conditions with different heights of the imaging unit 44, and a plurality of images are formed (image formation step ST123). In this embodiment, the imaging of the target area of ​​the workpiece 11 and the change of the height of the imaging unit 44 are repeatedly performed, and a plurality of images corresponding to each height are formed.

[0059] The distance at which the imaging unit 44 is in focus is predetermined by an optical system including an imaging lens, etc. Therefore, if the height of the imaging unit 44 at which an image focused on the effective area 44b is obtained is known, it becomes possible to calculate the height of the "target portion" based on the distance at which the imaging unit 44 is in focus.

[0060] In this embodiment, the controller 48 forms a plurality of images at each of four positions (target areas) (see FIG. 5) by repeatedly capturing images with the imaging unit 44 and changing the height of the imaging unit 44. Therefore, all of the formed images correspond to the imaging range 44a shown in FIG.

[0061] The position of the imaging unit 44 relative to each target area of ​​the workpiece 11 is adjusted by, for example, a method using pattern matching. Specifically, the controller 48 searches for a characteristic pattern (key pattern) present in each device 15 by pattern matching, and rotates the chuck table 12 based on this characteristic pattern so that the target processing line 13 is parallel to the X axis (θ alignment).

[0062] Next, the controller 48 images the outer edge (edge, side surface 11c) of the workpiece 11 from above using the imaging unit 44 and acquires the coordinates of this outer edge at three or more locations. Then, the controller 48 calculates the coordinates of the center O of the first surface 11a of the workpiece 11 based on the acquired coordinates of the outer edge. This allows the controller 48 to position the imaging unit 44 at each of four positions indicating the target area to be imaged, and to form multiple images at each position. The formed multiple images are recorded in the storage device 52 of the controller 48, linked to information about the height of the imaging unit 44 when each image was acquired.

[0063] In this embodiment, imaging by the imaging unit 44 and changing the height of the imaging unit 44 are repeated, but imaging by the imaging unit 44 may be repeated while raising or lowering the imaging unit 44 at any speed. In other words, the procedure for forming a plurality of images (image forming step ST123) includes such a case.

[0064] After the multiple images are formed, an image that is in focus on the effective area 44b is extracted, and the height of the imaging unit 44 when this extracted image was obtained is recorded as the in-focus height (height recording step ST124). As described above, if the height of the imaging unit 44 at which the image that is in focus on the effective area 44b is obtained is determined, the height of the "target portion" can be calculated based on the distance at which the imaging unit 44 is in focus.

[0065] Therefore, in this embodiment, the controller 48 extracts, from among the multiple images obtained at each of the four positions (target areas), the image in which the workpiece 11 (first surface 11a) is most clearly visible in the effective area 44b as the in-focus image. The controller 48 then records the height of the imaging unit 44 associated with the extracted image as the in-focus height at each position. Note that, for example, one method for extracting an in-focus image in the effective area 44b is to compare the contrast of the effective area 44b between the multiple images obtained, but images may also be extracted using other methods.

[0066] After the in-focus height at each position is recorded, the height of the "target portion" is calculated based on this in-focus height and the distance at which the imaging unit is in focus (height calculation step ST125).

[0067] For example, the controller 48 calculates the difference between the distance d at which the imaging unit 44 is in focus and the in-focus height h1 at the position (a, 0) as the height H1 (= h1 - d) of the "target portion" (the line to be processed 13, etc.) at the position (a, 0). Also, for example, the controller 48 calculates the difference between the distance d and the in-focus height h2 at the position (-a, 0) as the height H2 (= h2 - d) of the "target portion" (the line to be processed 13, etc.) at the position (-a, 0).

[0068] Similarly, for example, the controller 48 calculates the difference between the distance d and the height h3 at the time of focusing at the position (0, b) as the height H3 (= h3 - d) of the "target portion" (such as the line to be processed 13) at the position (0, b). Also, for example, the controller 48 calculates the difference between the distance d and the height h4 at the time of focusing at the position (0, -b) as the height H4 (= h4 - d) of the "target portion" (such as the line to be processed 13) at the position (0, -b).

[0069] Since the distance d at which the imaging unit 44 is in focus is substantially a constant, the in-focus heights h1 to h4 at each position can be treated in the same way as the heights H1 to H4 of the first surface 11a of the workpiece 11 at each position. Therefore, the procedure for calculating the height of this target (height calculation step ST125) may be omitted.

[0070] After the in-focus heights h1 to h4 at each position are recorded, or after the heights H1 to H4 of the first surface 11a of the workpiece 11 at each position are calculated, the height of the cutting unit 38 when processing the workpiece 11 is set, and as shown in Figure 3, the workpiece 11 is processed based on these set conditions (processing step ST13).

[0071] For example, the controller 48 uses the height H1 (=h1-d) of the "target portion" at the position (a,0) to set the height of the cutting unit 38 at the position (a,0). When it is desired to form a groove having a depth D (target depth) from the first surface 11a on the planned processing line 13, for example, the controller 48 sets the height of the cutting unit 38 so that the lower end of the cutting blade 42 is positioned at a height of H1-D.

[0072] Furthermore, for example, the controller 48 sets the height of the cutting unit 38 at the position (-a, 0) using the height H2 (= h2-d) of the "target portion" at the position (-a, 0). For example, the controller 48 sets the height of the cutting unit 38 so that the lower end of the cutting blade 42 is positioned at a height of H2-D.

[0073] Furthermore, for example, the controller 48 sets the height of the cutting unit 38 at the position (0, b) using the height H3 (= h3 - d) of the "target portion" at the position (0, b). For example, the controller 48 sets the height of the cutting unit 38 so that the lower end of the cutting blade 42 is positioned at a height of H3 - D.

[0074] Furthermore, for example, the controller 48 sets the height of the cutting unit 38 at the position (0, -b) using the height H4 (= h4 - d) of the "target portion" at the position (0, -b). For example, the controller 48 sets the height of the cutting unit 38 so that the lower end of the cutting blade 42 is positioned at a height of H4 - D.

[0075] Furthermore, in this embodiment, the controller 48 estimates the height at an arbitrary position that has not actually been measured based on the heights H1 to H4 of the "target portion" calculated at each position or the heights h1 to h4 when in focus at each position, and sets the height of the cutting unit 38 at that position. In other words, the controller 48 estimates the inclination of the workpiece 11 based on the heights H1 to H4 of the "target portion" calculated at each position or the heights h1 to h4 when in focus at each position, and sets the height of the cutting unit 38 at that position.

[0076] However, if the workpiece 11 can be considered not to be tilted, such as when there is no significant difference between the heights H1 to H4 of the "target portion" calculated at each position or the heights h1 to h4 when in focus at each position, the controller 48 may average the heights H1 to H4 of the "target portion" calculated at each position or the heights h1 to h4 when in focus at each position.

[0077] Similarly, the controller 48 may use the height of one "target portion" or the height at one focused position as a representative value. However, even in these cases, the controller 48 may vary the height conditions of the cutting unit 38 at each position, taking into account factors such as wear of the cutting blade 42 during processing.

[0078] 7 is a perspective view schematically showing how the workpiece 11 is machined. After the conditions related to the height of the cutting unit 38 are set, the controller 48 rotates the cutting blade 42 at high speed to cut into the first surface 11a of the workpiece 11 under the corresponding conditions. That is, the controller 48 moves the chuck table 12 along the X-axis while adjusting the height of the cutting unit 38 in accordance with the set conditions.

[0079] As a result, the rotating cutting blade 42 cuts into the first surface 11a side of the workpiece 11 to the target depth, and grooves 19 are formed in the workpiece 11 along the intended processing lines 13, as shown in Fig. 7. When grooves 19 are formed along all of the intended processing lines 13, the processing method according to this embodiment is completed.

[0080] As described above, in the measurement method and processing method of this embodiment, a portion of the imaging range 44a of the imaging unit 44 including the lens is set as the effective area 44b, and then the target area of ​​the workpiece (object to be measured) 11 is imaged under multiple conditions with different heights of the imaging unit 44 to form multiple images.Therefore, even if the target area of ​​the workpiece 11 includes an uneven structure and the uneven structure is captured in each image, the height of the target part can be properly calculated by appropriately setting the effective area 44b.

[0081] That is, according to the measuring method and processing method of this embodiment, even if there is a bump electrode (uneven structure) 17 on the first surface (surface) 11a of the workpiece 11, it is possible to measure the height of the target portion (the first surface 11a on the line to be processed 13). Then, it is possible to process the workpiece 11 to the target depth.

[0082] The present invention is not limited to the above-described embodiment and can be implemented in various modifications. For example, in the above-described embodiment, the procedure for specifying the position of the target area to be imaged (position specifying step ST121) is followed by the procedure for setting the effective area 44b (effective area setting step ST122), but the order of these steps may be reversed.

[0083] Furthermore, in the above-described embodiment, the measuring method and processing method implemented in the cutting device 2 have been described, but the measuring method and processing method of the present invention may be implemented in other devices. For example, the measuring method and processing method of the present invention may be implemented in a laser processing device having a condenser that focuses a laser beam on the workpiece 11, or a tool cutting device in which a tool called a tool made of cemented carbide or the like is attached to a spindle.

[0084] Similarly, the measuring method and processing method of the present invention may be practiced in a grinding device in which a grinding tool called a grinding wheel with a grinding stone fixed to the bottom is attached to a spindle, a polishing device in which a polishing tool called a polishing pad made of nonwoven fabric, polyurethane, etc. In addition, the measuring method and processing method of the present invention may also be practiced in devices that perform liquid injection, etching, sandblasting, tape application, film formation, etc.

[0085] In addition, the structures, methods, etc. according to the above-described embodiments and modifications may be modified as appropriate without departing from the scope of the present invention. [Explanation of symbols]

[0086] 2: Cutting equipment (processing equipment) 4: Base 6: Cassette table 8: Cassette 10: Chuck table moving mechanism (processing feed mechanism) 12: Chuck table (holding table) 14:Frame body 16: Holding plate 18: Clamp 20:Support structure 22: Cutting unit movement mechanism (indexing feed mechanism, cutting feed mechanism) 38: Cutting unit (processing unit) 40: Spindle 42: Cutting blade (grinding tool for processing) 44: Imaging unit (camera) 44a: Imaging range (field of view, target area) 44b: Effective area 46: Cleaning unit 48: Controller (control unit) 50: Processing equipment 52: Storage device 54: Input / output device (input device, output device) 11: Workpiece (object to be measured) 11a: 1st side (front) 11b: 2nd side (back side) 11c: Side 11d: Notch 13: Processing line (street) 15: Device 17: Bump electrode (uneven structure) 19: Groove 21: Tape (dicing tape) 23: Frame

Claims

1. A processing method for processing a part of a first surface of a workpiece having a concave-convex structure on the first surface, comprising: an image forming step of capturing images of a target area of ​​the workpiece under a plurality of conditions with different heights of an imaging unit to form a plurality of images; a height recording step of recording the height of the imaging unit when the image is obtained in focus in an effective area that is a part of the imaging range of the imaging unit including the lens; a processing step of processing the part of the first surface of the workpiece to a target depth using conditions that are set based on the height of the imaging unit recorded in the height recording step; A processing method comprising:

2. the workpiece has bump electrodes as the uneven structure, 2. The processing method according to claim 1, further comprising an effective area setting step of setting the effective area so that an area where no bump electrodes are present is captured in the effective area when the target area of ​​the workpiece is imaged.

3. 3. The processing method according to claim 1, further comprising a position designation step of designating a position of the target region of the workpiece.

4. A measurement method for measuring the height of a target portion of a measurement object using an imaging unit including a lens, comprising: an image forming step of capturing images of a target area of ​​the measurement object under a plurality of conditions where the imaging unit is at different heights, and forming a plurality of images; a height recording step of recording the height of the imaging unit when the image in focus in an effective area that is a part of the imaging range of the imaging unit is obtained; a height calculation step of calculating a height of the target portion of the measurement object based on the height of the imaging unit recorded in the height recording step and a distance at which the imaging unit is in focus; Measurement methods including:

5. the object to be measured has bump electrodes on its surface, 5. The measuring method according to claim 4, further comprising an effective area setting step of setting the effective area so that an area where no bump electrodes are present is captured in the effective area when the target area of ​​the object to be measured is imaged.

6. 6. The measurement method according to claim 4, further comprising a position designation step of designating a position of the target region of the measurement object.

Images