Measuring method and processing apparatus

Abstract

To measure the size of a cutting blade by using a cutting groove.SOLUTION: A method of measuring a size of a workpiece in a processing apparatus for processing the workpiece with a dicing blade, the method comprising the steps of: holding the workpiece on a holding table; and Cut the dicing blade on an upper surface of the workpiece held on the holding table. According to an aspect of the present invention, there is provided a measuring method including a cut groove forming step of forming a cut groove on an upper surface of a workpiece, a depth measuring step of measuring a depth of the cut groove at a plurality of positions in a longitudinal direction of the cut groove while relatively moving a head portion of a displacement gauge provided above the cut groove and a holding table that holds the workpiece along the longitudinal direction of the cut groove, and a calculating step of calculating a size of a cutting blade based on the depth of the cut groove at the plurality of positions.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measurement method for measuring the size of a cutting blade in a processing device that processes a workpiece with the cutting blade, and to a processing device having a holding table and a cutting unit. [Background technology]

[0002] Semiconductor device chips are mounted on electronic devices such as mobile phones and PCs (Personal Computers). Semiconductor device chips are manufactured by, for example, forming a plurality of devices, such as integrated circuits (ICs), on the surface of a silicon wafer and then dividing the silicon wafer into individual devices.

[0003] When dividing a silicon wafer into device units, for example, a cutting device is used. The cutting device includes a chuck table that holds the silicon wafer by suction and a cutting unit having a cylindrical spindle (see, for example, Patent Documents 1 and 2).

[0004] A cutting blade with an annular cutting edge is attached to the tip of the spindle so that it is approximately concentric with the center of rotation of the spindle. The cutting blade has abrasive grains made of diamond or the like and a bond material that secures the abrasive grains. The cutting blade can be an electroplated blade, a resin blade, a metal blade, or the like, and is selected appropriately depending on the object to be cut.

[0005] Incidentally, when cutting a silicon wafer, an operation called chopper cut setup is performed to detect the origin position of the cutting blade in the Z-axis direction (e.g., height direction) of the cutting device. When chopper cut setup is performed, for example, a sub-chuck table, which is a chuck table different from the chuck table that holds the silicon wafer by suction, is used.

[0006] Specifically, first, the single-crystal silicon substrate is suction-held on the holding surface of the sub-chuck table. Next, the cutting unit is lowered along the Z-axis direction from above the sub-chuck table while the cutting blade is rotating around the spindle, so that the lower end of the cutting blade cuts into the single-crystal silicon substrate, forming a cut groove on the upper surface of the single-crystal silicon substrate.

[0007] The length of the cut groove in the longitudinal direction is then measured using a camera installed in the cutting device, and the depth from the surface of the single crystal silicon substrate to the lowest point of the cut groove is calculated based on the length of the cut groove obtained by this measurement and the previously determined radius of the cutting blade.

[0008] The position of the holding surface of the sub-chuck table in the Z-axis direction is predetermined in the cutting device. In addition, since the thickness of the single crystal silicon substrate is known, the position of the upper surface of the single crystal silicon substrate in the Z-axis direction is also known.

[0009] Therefore, by calculating the depth of the lowest point of the cutting groove, the position of the lowest point of the cutting blade can be detected relative to a predetermined position in the Z-axis direction (e.g., the holding surface of the sub-chuck table) (see, for example, Patent Documents 1 and 2).

[0010] However, the radius of the cutting blade is not always constant because it decreases due to wear, so even if the length of the cutting groove is measured, the position of the lowest point of the cutting blade may not always be accurately detected. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-59365 [Patent Document 2] Japanese Patent Publication No. 2022-85183 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention has been made in view of the above problems, and has as its object to measure the size of a cutting blade by using a cutting groove formed on the upper surface of a workpiece. [Means for solving the problem]

[0013] According to one aspect of the present invention, there is provided a measurement method for measuring the size of a cutting blade in a processing device that processes a workpiece with the cutting blade, the measurement method comprising: a holding step for holding the workpiece on a holding table; a cutting groove forming step for cutting the cutting blade into the upper surface of the workpiece held on the holding table to form a cutting groove on the upper surface of the workpiece; a depth measurement step for measuring the depth of the cutting groove at multiple locations in the longitudinal direction of the cutting groove while moving a head portion of a displacement meter provided above the cutting groove and the holding table holding the workpiece relatively along the longitudinal direction of the cutting groove; and a calculation step for calculating the size of the cutting blade based on the depth of the cutting groove at multiple locations in the longitudinal direction.

[0014] Preferably, in the depth measurement step, the depth of the cutting groove at multiple locations in the longitudinal direction is measured at each of multiple positions in a predetermined direction perpendicular to the longitudinal direction in a planar view, and the measurement method further includes a three-dimensional image creation step of creating a three-dimensional image of the cutting groove based on the depth data of the cutting groove obtained in the depth measurement step.

[0015] Preferably, the measuring method further comprises a determining step of determining whether the tip shape of the cutting blade is good or bad based on the shape of a region in the three-dimensional image that corresponds to the opening of the cutting groove.

[0016] Preferably, the upper surface of the holding table has a rectangular shape, and in the holding process, a rectangular substrate corresponding to the shape of the upper surface of the holding table is held as the workpiece, and in the cutting groove forming process, the cutting groove is formed in the workpiece held by the holding table.

[0017] According to another aspect of the present invention, there is provided a processing device comprising: a holding table for holding a workpiece; a cutting unit having a spindle and cutting the workpiece with a cutting blade attached to the tip of the spindle; a head portion of a displacement meter having a head portion provided above the holding table and measuring the depth of a cutting groove formed on the upper surface of the workpiece by the cutting blade; and a controller having a processor and memory and controlling the operation of the holding table, the cutting unit and the displacement meter, wherein the controller measures the depth of the cutting groove at multiple points in the longitudinal direction of the cutting groove while moving the displacement meter and the holding table holding the workpiece relatively along the longitudinal direction of the cutting groove, and calculates the size of the cutting blade based on the depth of the cutting groove at multiple points in the longitudinal direction.

[0018] Preferably, the controller measures the depth of the cutting groove at multiple locations in the longitudinal direction at each of multiple positions in a predetermined direction perpendicular to the longitudinal direction in a planar view using the displacement meter, and creates a three-dimensional image of the cutting groove based on the data on the depth of the cutting groove in the longitudinal direction and the predetermined direction.

[0019] Preferably, the controller determines whether the tip shape of the cutting blade is good or bad based on the shape of a region in the three-dimensional image that corresponds to the opening of the cutting groove.

[0020] Preferably, the holding table is a disk-shaped first holding table, or a second holding table that is provided adjacent to the first holding table and has a shape different from that of the first holding table in a plan view. [Effects of the Invention]

[0021] In a measurement method according to one aspect of the present invention, the head of the displacement meter and the holding table holding the workpiece are moved relatively along the longitudinal direction of the cutting groove, while the depth of the cutting groove is measured at multiple points along the longitudinal direction of the cutting groove (depth measurement process), and the size of the cutting blade is calculated based on the depth of the cutting groove at these multiple points (calculation process).

[0022] For example, this measurement method measures the length L of the cutting groove in the longitudinal direction and the depth D of the cutting groove at the deepest position measured by a displacement meter, and the radius of the cutting blade can be calculated using these length L and depth D. Furthermore, since the depth D can be measured directly, the origin position of the cutting blade can also be detected.

[0023] In another aspect of the processing device of the present invention, the controller measures the depth of the cutting groove at multiple points along the longitudinal direction of the cutting groove while moving the head of the displacement meter and the holding table holding the workpiece relatively along the longitudinal direction of the cutting groove, and calculates the size of the cutting blade based on the depth of the cutting groove at these multiple points.

[0024] For example, the controller can obtain the length L of the cutting groove in the longitudinal direction and the depth D of the cutting groove at the deepest position measured by the displacement meter, and calculate the radius of the cutting blade using these length L and depth D. In addition, since the depth D can be measured directly, the origin position of the cutting blade can also be detected. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a flow diagram of a measurement method. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] 10A to 10C are diagrams illustrating a cutting groove forming step. [Figure 5] FIG. 5(A) is a partially cross-sectional side view at the start of the depth measurement process, and FIG. 5(B) is a plan view at the start of the depth measurement process. [Figure 6] FIG. 6(A) is a partially cross-sectional side view showing the depth measurement step, and FIG. 6(B) is a plan view showing the depth measurement step. [Figure 7] FIG. 10 is a diagram illustrating a calculation process. [Figure 8] 10A and 10B are diagrams illustrating a three-dimensional image creation process and a determination process. [Figure 9]FIG. 9(A) shows one example of an opening, and FIG. 9(B) shows another example of an opening. [Figure 10] FIG. 10 is a diagram illustrating a modified example of the calculation process. [Figure 11] FIG. 10 is a perspective view of the wafer unit after a cut groove forming step. DETAILED DESCRIPTION OF THE INVENTION

[0026] (First embodiment) An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a flow diagram of a measurement method for measuring the size (e.g., radius) of a cutting blade 46 (see Fig. 4).

[0027] In this embodiment, the steps are performed in the following order: a holding step S10, a cutting groove forming step S20, a depth measuring step S30, a calculation step S40, a three-dimensional image creating step S50, and a determination step S60. First, with reference to FIG. 2, a cutting device (processing device) 2 in which the steps are performed will be described.

[0028] Fig. 2 is a perspective view of the cutting device 2. Note that Fig. 2 shows some of the components of the cutting device 2 in functional blocks. The X-axis direction (processing feed direction), Y-axis direction (indexing feed direction), and Z-axis direction (up-down direction, height direction) shown in Fig. 2 are perpendicular to one another.

[0029] The cutting device 2 includes a base 4 that supports or houses each of the components. A rectangular opening 4a is provided at the front corner of the base 4. A cassette elevator 6 that can be raised and lowered by an elevation mechanism is provided in the opening 4a.

[0030] A cassette 8 containing a plurality of wafers 11 is placed on the upper surface of the cassette elevator 6. The wafers 11 include, for example, silicon wafers, which are disk-shaped single crystal silicon substrates. There are no limitations on the material, shape, structure, size, etc. of the wafers 11.

[0031] A plurality of mutually orthogonal dividing lines are set on the front surface 11a of the wafer 11. Devices such as ICs are formed in each of a plurality of rectangular regions defined by the dividing lines.

[0032] A central portion of a dicing tape 13 having a diameter larger than that of the wafer 11 is attached to the back surface 11b of the wafer 11. A ring-shaped frame 15 made of metal is attached to the outer periphery of the dicing tape 13.

[0033] That is, the wafer 11, the dicing tape 13, and the frame 15 are integrated together. The wafer 11 is accommodated in the cassette 8 in the state of a wafer unit 17 supported on the frame 15 via the dicing tape 13 in this manner.

[0034] A rectangular opening 4b with its longitudinal direction aligned along the X-axis direction is formed near the cassette elevator 6. An X-axis direction movement mechanism (processing feed unit) (not shown) including a ball screw is provided below the opening 4b.

[0035] A rectangular table cover 12 is provided above the X-axis direction movement mechanism, and bellows-shaped cover members 14 that are extendable and contractible along the X-axis direction are provided on both sides of the table cover 12 in the X-axis direction. A chuck table (holding table, first holding table) 16 that holds the wafer 11 by suction is provided on the table cover 12.

[0036] The chuck table 16 has a disk-shaped frame made of metal. A disk-shaped recess is formed in the radial center of the frame, and a disk-shaped porous plate is fixed in this recess using an adhesive or the like.

[0037] The upper surface of the frame and the upper surface of the porous plate are substantially flush with each other and function as a substantially flat holding surface 16a for suction-holding the wafer 11. The holding surface 16a is substantially parallel to the XY plane. A suction path (not shown) is formed in the frame, and one end of the suction path is connected to a suction source (not shown) such as a vacuum pump.

[0038] The negative pressure generated by the suction source is transmitted to the upper surface of the porous plate. A plurality of (four in this embodiment) clamp units 16b are provided around the chuck table 16. Each clamp unit 16b clamps and fixes the frame 15 in the vertical direction.

[0039] A rotation shaft (not shown) is provided at the center of the bottom surface of the frame. The rotation shaft is rotated within a predetermined angular range by a rotation drive source (not shown) such as a motor. In other words, the chuck table 16 can rotate within a predetermined angular range.

[0040] The table cover 12 is provided with rectangular sub-chuck tables (holding tables, second holding tables) 18. In this embodiment, one sub-chuck table 18 is provided at each of two corners of the table cover 12 adjacent to the chuck table 16.

[0041] The sub-chuck table 18 is smaller than the chuck table 16 in the XY plane view and has a different shape from the chuck table 16. The sub-chuck table 18 of this embodiment has an upper surface 18a that is rectangular in the XY plane, and the length of each side is smaller than the diameter of the chuck table 16.

[0042] A plurality of suction grooves are provided in a grid pattern on the upper surface 18a of the sub-chuck table 18. Negative pressure is transmitted to each suction groove from the suction source described above. A rectangular substrate (workpiece) 19 having a shape different from that of the wafer 11 is placed on the upper surface 18a of the sub-chuck table 18.

[0043] The rectangular substrate 19 has upper and lower surfaces each having substantially the same shape as the upper surface 18a of the sub-chuck table 18. In this embodiment, a single crystal silicon substrate is used as the rectangular substrate 19. The rectangular substrate 19 is held by suction to the upper surface 18a of the sub-chuck table 18 by negative pressure while in contact with the upper surface 18a.

[0044] Above the opening 4b, a gate-shaped support structure 20 is provided so as to straddle the opening 4b. Two cutting unit movement mechanisms 22, each including an indexing feed unit and a cutting feed unit, are provided on one side of the support structure 20.

[0045] Each cutting unit moving mechanism 22 shares a pair of Y-axis guide rails 24 fixed to one surface of the support structure 20. The longitudinal direction of each Y-axis guide rail 24 is approximately parallel to the Y-axis direction.

[0046] A first moving plate 26 is slidably attached to the Y-axis direction guide rail 24. A nut portion (not shown) is provided on the back surface of each first moving plate 26. One screw shaft 28 is rotatably coupled to one nut portion. The longitudinal direction of each screw shaft 28 is approximately parallel to the Y-axis direction.

[0047] A drive source 30 such as a servo motor or a stepping motor is connected to one end of each screw shaft 28. When the screw shaft 28 is rotated by the drive source 30, the first moving plate 26 moves along the Y-axis guide rail 24.

[0048] A pair of Z-axis guide rails 32 is provided on the surface of each first moving plate 26. The longitudinal direction of each Z-axis guide rail 32 is approximately parallel to the Z-axis direction. A second moving plate 34 is slidably fixed to the Z-axis guide rails 32.

[0049] A nut portion (not shown) is provided on the back side of the second moving plate 34, and a screw shaft 36 is rotatably coupled to this nut portion. The longitudinal direction of the screw shaft 36 is approximately parallel to the Z-axis direction. A drive source 38 such as a servo motor or a stepping motor is coupled to the upper end of the screw shaft 36.

[0050] When the screw shaft 36 is rotated by the drive source 38, the second moving plate 34 moves along the Z-axis direction. A cutting unit 40 is connected to the lower part of the second moving plate 34. The cutting unit 40 has a spindle housing 42 whose longitudinal direction is aligned with the Y-axis direction.

[0051] A portion of a cylindrical spindle 44 (see FIG. 4) is housed within the spindle housing 42. A rotation drive source (not shown), such as a servo motor, for rotating the spindle 44 is provided within the spindle housing 42. The spindle 44 is supported within the spindle housing 42 by a hydrostatic air bearing.

[0052] A cutting blade 46 (see FIG. 4) having an annular cutting edge is attached to the tip of the spindle 44, utilizing a receiving flange and a holding flange. The cutting blade 46 shown in FIG. 4 is a so-called hubless type (also called a washer type), but the cutting blade 46 may also be a so-called hub type in which the cutting edge is fixed to one surface of a disk-shaped base.

[0053] During cutting, the spindle 44 is rotated at high speed (e.g., 30,000 rpm), and the cutting blade 46, which rotates at high speed together with the spindle 44, is moved downward along the Z-axis direction at a predetermined speed (e.g., 50 μm / s) to cut into the wafer 11 or rectangular substrate 19.

[0054] As a result, the wafer 11 or rectangular substrate 19 is cut (i.e., processed) by the cutting blade 46. This type of cutting mode is called chopper cutting. Now, returning to FIG. 2, the description of the components of the cutting device 2 will continue.

[0055] A microscope camera unit 48 is provided at a position adjacent to each cutting unit 40. The microscope camera unit 48 is fixed to the second movable plate 34 and is movable together with the cutting unit 40 in the Y-axis direction and the Z-axis direction.

[0056] The microscope camera unit 48 has an image sensor, a predetermined optical system, a lens, etc. The microscope camera unit 48 uses, for example, visible light to capture an image of the wafer 11 and the rectangular substrate 19. For example, the image obtained by capturing the image of the wafer 11 is used for alignment of the wafer 11, kerf check, etc.

[0057] A head portion 50a of a laser displacement meter (displacement meter) 50 is provided in the Y-axis direction of the microscope camera unit 48. The head portion 50a of the laser displacement meter 50 is provided above the chuck table 16 and the sub-chuck table 18. The head portion 50a is also fixed to the second moving plate 34, and is movable together with the cutting unit 40 in the Y-axis direction and the Z-axis direction.

[0058] However, the head portion 50a does not necessarily have to be fixed to the second moving plate 34. For example, the head portion 50a may be configured to be movable independently from the cutting unit 40 in the Y-axis direction or in both the Y-axis direction and the Z-axis direction.

[0059] The head unit 50a includes a light source such as an LED that emits a laser beam of a predetermined wavelength, a cylindrical lens for shaping the laser beam emitted from the light source, an optical system for receiving reflected light from the irradiated object, and an image sensor that receives the reflected light and performs photoelectric conversion.

[0060] The head portion 50a irradiates the wafer 11 held by suction on the chuck table 16 or the rectangular substrate 19 held by suction on the sub-chuck table 18 with a line laser La (see FIG. 5(A)).

[0061] In this embodiment, the longitudinal direction of the irradiated area of ​​the line laser La irradiated from the head unit 50a onto the irradiated object is along the Y-axis direction (see FIGS. 5(B) and 6(B)). In FIGS. 5(B) and 6(B), the irradiated area of ​​the line laser La is indicated by a dashed line along the Y-axis direction.

[0062] When a cutting groove 21 whose longitudinal direction 21a is along the X-axis direction is formed on the upper surface of the wafer 11 or rectangular substrate 19, the line laser La is irradiated onto the wafer 11 or rectangular substrate 19 so as to intersect with the longitudinal direction 21a of the cutting groove 21 (see Figure 6(B)).

[0063] The depth of the cut groove 21 can be measured by moving the sub-chuck table 18 (or chuck table 16) along the X-axis direction while the rectangular substrate 19 (or wafer 11) is irradiated with the line laser La.

[0064] In addition, a two-dimensional profile of the cutting groove 21 in the longitudinal direction 21a (i.e., the X-axis direction) of the cutting groove 21 (see Figure 7), as well as a three-dimensional profile of the cutting groove 21 in the longitudinal direction 21a and width direction 21b (i.e., the Y-axis direction) of the cutting groove 21 can be obtained (see Figure 8).

[0065] A cover member (not shown) that forms a side wall is provided above the base 4 of the cutting device 2. A touch panel display 52 is provided on the front surface of the cover member. The touch panel display 52 functions as a display device that displays two-dimensional images obtained by the microscope camera unit 48, two-dimensional images obtained by the laser displacement meter 50 (see FIG. 7), three-dimensional image 23 (see FIG. 8), etc.

[0066] The touch panel display 52 also functions as an input device that allows the operator to input instructions by touching the screen. Note that instead of the touch panel display 52, a display device that does not function as an input device may be provided in the cutting device 2. In this case, however, an input device (keyboard, mouse, trackball, touchpad, digitizer, etc.) is provided separately.

[0067] The operations of the cassette elevator 6, the X-axis direction moving mechanism, the chuck table 16, the sub-chuck table 18, the cutting unit moving mechanism 22, the cutting unit 40, the microscope camera unit 48, the laser displacement meter 50, the touch panel display 52, etc. are controlled by a controller 54.

[0068] The controller 54 is configured by a computer having a processor 54a, such as a central processing unit (CPU), and a memory 54b. The memory 54b includes a main storage device such as a dynamic random access memory (DRAM) and an auxiliary storage device such as a flash memory.

[0069] The auxiliary storage device stores software including a predetermined program. The functions of the controller 54 are realized by operating the processor 54a in accordance with this software.

[0070] The controller 54 of this embodiment measures the depth of the cutting groove 21 at multiple locations in the longitudinal direction 21a of the cutting groove 21 in the XY plane, and calculates the size of the cutting blade 46 (more specifically, the radius of the outer edge of the cutting edge) based on the depth of the cutting groove 21 at these multiple locations.

[0071] In addition, the controller 54 of this embodiment creates a three-dimensional image 23 of the cutting groove 21 based on the data on the depth of the cutting groove 21 obtained via the head portion 50a of the laser displacement meter 50, and displays the three-dimensional image 23 on the touch panel display 52.

[0072] However, the dedicated controller of the laser displacement meter 50 electrically connected to the head portion 50a may be provided separately from the controller 54 of the cutting device 2, and this dedicated controller and the controller 54 may be electrically connected.

[0073] In this case, a dedicated controller for the laser displacement meter 50 creates a three-dimensional image 23 obtained by the laser displacement meter 50, and displays the three-dimensional image 23 on the touch panel display 52 via the controller 54 or without going through the controller 54.

[0074] Next, a description will be given of each step (see FIG. 1) of a measurement method for measuring the size of the cutting blade 46 using the cutting device 2. In the measurement method of this embodiment, the cutting blade 46 forms the cutting groove 21 in the rectangular substrate 19 held by suction on the sub-chuck table 18, but the cutting groove 21 may also be formed in the wafer 11 held by suction on the chuck table 16.

[0075] 3 is a diagram showing a holding step S10 in which rectangular substrate 19 is suction-held by sub-chuck table 18. In holding step S10, one surface (top surface) 19a of rectangular substrate 19 is exposed upward, and the other surface 19b of rectangular substrate 19 is in contact with top surface 18a. Holding step S10 may be performed before or after wafer unit 17 is suction-held by chuck table 16.

[0076] After the holding step S10, the cutting groove forming step S20 is performed. Fig. 4 is a diagram showing the cutting groove forming step S20. In the cutting groove forming step S20, the X-axis direction position of the sub-chuck table 18 is adjusted by the X-axis direction moving mechanism, and the Y-axis direction position of the cutting blade 46 is adjusted by the cutting unit moving mechanism 22.

[0077] Then, the cutting unit 40 including the cutting blade 46, which is rotating at high speed, is lowered along the Z-axis direction by the cutting unit moving mechanism 22. This causes the cutting blade 46 to cut into one surface 19a of the rectangular substrate 19, forming a cutting groove 21 in one surface 19a of the rectangular substrate 19, with the longitudinal direction 21a aligned with the X-axis direction.

[0078] The depth of the cut groove 21 is adjusted appropriately depending on the thickness of the rectangular substrate 19, but is set to a depth that does not reach from one surface 19a to the other surface 19b of the rectangular substrate 19 (for example, 30 μm from one surface 19a). At this stage, the exact depth of the cut groove 21 is unknown. After the cut groove 21 is formed, the cutting blade 46 is raised and separated from the rectangular substrate 19.

[0079] Then, the distance from the head portion 50a of the laser displacement meter 50 to one surface 19a of the rectangular substrate 19 is adjusted to a distance (for example, about 20 mm to 300 mm) suitable for measuring the depth of the cut groove 21 with the laser displacement meter 50. Thereafter, the depth measuring step S30 is performed.

[0080] 5(A) is a partially cross-sectional side view at the start of the depth measurement step S30, and FIG. 5(B) is a plan view at the start of the depth measurement step S30. At the start of the depth measurement step S30, the position of the head unit 50a in the Y-axis direction is adjusted so that the extension line of the cut groove 21 intersects with the line laser La ahead in the movement direction of the rectangular substrate 19.

[0081] 6(A) is a side view showing the depth measurement step S30, and Fig. 6(B) is a plan view showing the depth measurement step S30. In the depth measurement step S30, the head portion 50a of the laser displacement meter 50 and the sub-chuck table 18 that holds the rectangular substrate 19 by suction are moved relatively along the X-axis direction to measure the depth of the cut groove 21 at multiple locations in the longitudinal direction 21a of the cut groove 21.

[0082] In this embodiment, while the spatial position of the head portion 50a is fixed and the irradiation of the line laser La from the laser displacement meter 50 is continued, the sub-chuck table 18 is moved along the X-axis direction at a predetermined processing feed rate (e.g., 50 mm / s) by the X-axis direction moving mechanism.

[0083] In addition, since the line laser La is irradiated onto one surface 19a so as to intersect with the cutting groove 21, it is also possible to measure the depth of multiple points in the longitudinal direction 21a of the cutting groove 21 at each of multiple positions in the width direction 21b of the cutting groove 21 (i.e., a predetermined direction perpendicular to the longitudinal direction 21a of the cutting groove 21 when viewed in a plane).

[0084] 7 is a diagram showing data on the depth of the cut groove 21 in a plane that passes through the cut groove 21 and is parallel to the XZ plane, and is a diagram illustrating the calculation step S40. The horizontal axis of FIG. 7 corresponds to the X-axis direction, and the vertical axis of FIG. 7 corresponds to the Z-axis direction.

[0085] Each circle in Fig. 7 indicates the height position of the bottom surface of the one surface 19a or the cutting groove 21 obtained in the depth measurement step S30. For ease of explanation, the outline of the cutting blade 46 estimated based on the depth data is shown by a dashed circle in Fig. 7. Furthermore, Fig. 7 also shows the length L of the cutting groove 21 in the longitudinal direction 21a and the depth D of the lowest point of the cutting groove 21 based on the one surface 19a.

[0086] The length L of the cutting groove 21 in the longitudinal direction 21a is calculated, for example, from the difference between the position where the height position starts to decrease from a constant value (position X1 in the X-axis direction) and the position where the height position stops increasing and becomes a constant value (position X2 in the X-axis direction). The following equation (1) holds between the radius r (unknown variable) of the cutting blade 46, the length L, and the depth D.

[0087]

number

[0088] Therefore, the radius r (i.e., size) of the cutting blade 46 can be calculated from the equation (1) based on the depths of the cutting grooves 21 at multiple locations. In this embodiment, the radius r can be calculated by substituting the length L between two locations (positions X1 and X2) that are at the same height as the one surface 19a and have a depth of approximately zero, and one location with a depth D, into the equation (1) and solving for the radius r.

[0089] The size of the cutting blade 46 is not limited to the radius r. For example, the diameter of the cutting blade 46 obtained by doubling the calculated radius r (i.e., 2r) may be regarded as the size of the cutting blade 46.

[0090] Assuming that the shape of the cutting groove 21 in the Y-axis direction is approximately uniform, the size of the cutting blade 46 is determined from the holding step S10 to the calculation step S40. However, there may be cases where the cutting blade 46 has an abnormal shape, such as uneven wear.

[0091] If an abnormality in shape occurs, the radius r of the cutting blade 46 obtained in the calculation step S40 will represent only a part of the overall image of the cutting blade 46. Therefore, in this embodiment, in order to grasp the shape of the cutting blade 46 more accurately, after the calculation step S40, a three-dimensional image creation step S50 is performed in which a three-dimensional image 23 of the cutting groove 21 is created.

[0092] 8 is a diagram showing a three-dimensional image creation step S50 and a determination step S60. In the three-dimensional image creation step S50, the controller 54 or a dedicated controller of the laser displacement meter 50 creates a three-dimensional image 23 of the cut groove 21 based on the depth data in the longitudinal direction 21a and width direction 21b of the cut groove 21 obtained in the depth measurement step S30.

[0093] In short, the cross-sectional shapes of the cutting groove 21 in the XZ plane (see FIG. 7) are joined in the Y-axis direction to create a three-dimensional image 23. Then, the controller 54 judges whether the tip shape of the cutting blade 46 is good or bad based on the shape of the area corresponding to the opening 21c of the cutting groove 21 in the three-dimensional image 23 (judging step S60).

[0094] Since the cutting groove 21 is formed by cutting the rotating cutting blade 46 from one surface 19a to the other surface 19b of the rectangular substrate 19, any irregularity in the shape of the cutting blade 46 appears in the opening 21c.

[0095] Figure 9(A) is a plan view of the cutting groove 21, and is an example of an ideal end of the longitudinal direction 21a of the opening 21c when the cutting groove 21 is formed on one surface 19a of the rectangular substrate 19 using a normal cutting blade 46.

[0096] In contrast, Figure 9(B) is a plan view of the cutting groove 21, and is an example of the end of the longitudinal direction 21a of the opening 21c when the cutting groove 21 is formed on one surface 19a of the rectangular substrate 19 using a cutting blade 46 with a portion of the outer periphery missing.

[0097] The memory 54b stores the ideal shape shown in Fig. 9(A). Specifically, the memory 54b stores (1) the allowable range (for example, within 90°±0.5') of the angle θ between the long side along the longitudinal direction 21a and the short side along the width direction 21b, and (2) the allowable range of the length d of the missing region in the longitudinal direction 21a (see Fig. 9(B)).

[0098] For example, the controller 54 determines that the tip shape of the cutting blade 46 is good if the shape of the obtained opening 21c is (A) within the allowable range of the angle θ and (B) within the allowable range of the length d of the missing area.

[0099] On the other hand, if the shape of the obtained opening 21c is (A) outside the allowable range of the angle θ, or (B) outside the allowable range of the length d of the missing area, the controller 54 determines that the tip shape of the cutting blade 46 is defective.

[0100] If the controller 54 determines that the tip shape of the cutting blade 46 is defective, it may dress the cutting blade 46 using a dressing board held by suction on a sub-chuck table 18 that is not holding the rectangular substrate 19 by suction, or a dressing board held by suction on the chuck table 16, to correct the tip shape (dressing process).

[0101] In conventional chopper cut setup, the radius r of the cutting blade 46 is assumed to be known, and the length L of the longitudinal direction 21a of the cutting groove 21 is measured using a camera or the like, and then the depth D of the cutting groove 21 is calculated using the formula (1).

[0102] However, in this embodiment, the radius r of the cutting blade 46 can be calculated using the length L of the cutting groove 21 in the longitudinal direction 21a and the depth D of the cutting groove 21 at its deepest position, each measured using a laser displacement meter 50.

[0103] Furthermore, since the depth D can be measured directly, it is also possible to detect the origin position of the cutting blade 46. Therefore, even if the radius r of the cutting blade 46 is reduced due to wear and is unknown, chopper cut setup can be performed more accurately.

[0104] 10 is a diagram showing a modification of the calculation step S40. In this modification, the radius r is calculated using three points (A1, A2, A3) that are located in the range from position X1 to position X2 in the X-axis direction and that are not all on a straight line.

[0105] Specifically, first, the intersection point (i.e., the radial center C of the cutting blade 46) between the perpendicular bisector of the line segment connecting points A1 and A2 and the perpendicular bisector of the line segment connecting points A2 and A3 is calculated, and then the distance (i.e., the radius r) from this intersection point to one of points A1, A2, or A3 is calculated.

[0106] (Second Modification) Incidentally, in the three-dimensional image creation step S50, in addition to creating the three-dimensional image 23 of the cutting groove 21, a three-dimensional image 23 of the cutting blade 46 estimated from the shape of the cutting groove 21 may be created. This makes it possible to calculate the radius r of the cutting blade 46 from the three-dimensional image 23 of the cutting blade 46.

[0107] (Second Embodiment) Next, a measurement method according to a second embodiment will be described with reference to Fig. 11. In the second embodiment, a cutting device 2 is also used, but a cutting groove 21 is formed in the peripheral excess region 11a2 of a wafer 11 held by suction on a chuck table 16, rather than in a rectangular substrate 19 held by suction on a sub-chuck table 18. This is what makes this embodiment different from the first embodiment.

[0108] In the holding step S10 of the second embodiment, first, the wafer unit 17 is transported to the chuck table 16, and the wafer 11 is sucked onto the holding surface 16a via the dicing tape 13, and the frame 15 is fixed with each clamp unit 16b, thereby holding the wafer unit 17 by suction.

[0109] Therefore, the chuck table 16 functions as a holding table that suction-holds the wafer 11 (workpiece). In the holding step S10 of the second embodiment, the front surface 11a of the wafer 11 is the upper surface that is exposed upward. However, if the dicing tape 13 is attached to the front surface 11a, the back surface 11b of the wafer 11 may be the upper surface that is exposed upward.

[0110] In the cutting groove forming step S20 after the holding step S10, the rotating cutting blade 46 is lowered along the Z-axis direction to cut into the outer peripheral excess region 11a2 of the surface 11a, thereby forming a cutting groove 21 in the outer peripheral excess region 11a2.

[0111] 11 is a perspective view of the wafer unit 17 after the cutting groove forming step S20 in the second embodiment. As shown in FIG. 11, the surface 11a has a device region 11a1 where a plurality of devices are provided, and a peripheral excess region 11a2 surrounding the device region 11a1.

[0112] The cutting groove 21 is formed in the outer peripheral excess region 11a2. The subsequent steps of the depth measurement step S30, the calculation step S40, the three-dimensional image creation step S50, and the determination step S60 are the same as those in the first embodiment.

[0113] In the second embodiment, the radius r of the cutting blade 46 can also be calculated using the length L of the cutting groove 21 in the longitudinal direction 21a and the depth D of the cutting groove 21 at its deepest position, each measured using a laser displacement meter 50.

[0114] Since the depth D can be measured directly, it is also possible to detect the origin position of the cutting blade 46. Therefore, even if the radius r of the cutting blade 46 is reduced due to wear and is unknown, chopper cut setup can be performed more accurately.

[0115] In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the object of the present invention.

[0116] In the above-described embodiment and variant examples, the steps from the holding step S10 to the determination step S60 are described, but the flow may end at the calculation step S40 in order to achieve the purpose of calculating the size of the cutting blade 46.

[0117] In the above-described embodiments and variations, a line laser La is formed using a cylindrical lens, but a pseudo line laser La as shown in Figures 5(B) and 6(B) may be formed by arranging the focal points of normal laser beams transmitted through multiple optical fibers along a predetermined direction (e.g., the Y-axis direction).

[0118] Furthermore, a laser displacement meter (displacement meter) having a head that irradiates a normal laser beam (i.e., a laser beam that irradiates a dot-like area on the irradiated object rather than a line-like area) may be used instead of the true line laser La and the pseudo line laser La. In this case, the diameter of the focal point of the laser beam is set smaller than the width direction 21b of the cut groove 21, and the laser beam scans the cut groove 21 one or more times.

[0119] For example, by moving the focal point of the laser beam and the sub-chuck table 18 (or the chuck table 16) relatively along the X-axis direction, the depth of the cutting groove 21 is measured at least in the range from one end of the cutting groove 21 (for example, position X1 in Figure 7) to the other end of the cutting groove 21 (for example, position X2 in Figure 7).

[0120] Next, the focal point of the laser beam and the sub-chuck table 18 (or chuck table 16) are moved relatively along the Y-axis direction by a predetermined indexing feed amount that is smaller than the width direction 21b of the cut groove 21.

[0121] Thereafter, the depth of the cut groove 21 is measured again in at least the range from one end to the other end of the cut groove 21. In this way, by scanning the cut groove 21 with the laser beam multiple times, it is possible to obtain results similar to those of the depth measurement step S30 using the line laser La.

[0122] Of course, the depth measurement step S30 may be completed by a single scan instead of multiple scans. In this case, the three-dimensional image creation step S50 cannot be performed, but the calculation step S40 shown in Figures 7 and 10 can be performed.

[0123] Note that, if the length of the width direction 21b of the cut groove 21 is sufficiently large and / or the diameter of the probe is sufficiently small so that the probe can enter the cut groove 21, a contact-type linear gauge (displacement meter) may be used instead of the laser displacement meter. The linear gauge has a head portion equipped with the above-mentioned probe. [Explanation of symbols]

[0124] 2: Cutting equipment (processing equipment), 4: Base, 4a, 4b: Opening 6: Cassette elevator, 8: Cassette 11: Wafer (workpiece), 11a: Front side, 11b: Back side 11a1: device area, 11a2: peripheral surplus area 12: table cover, 14: cover member 13: Dicing tape, 15: Frame, 17: Wafer unit 16: Chuck table (holding table, first holding table) 16a: holding surface, 16b: clamp unit 18: Sub-chuck table (holding table, second holding table), 18a: Upper surface 19: Rectangular substrate (workpiece), 19a: One side (top surface), 19b: Other side 20:Support structure 21: Cut groove, 21a: Longitudinal direction, 21b: Width direction, 21c: Opening 22: Cutting unit movement mechanism 23: Three-dimensional image 24: Y-axis direction guide rail, 26: first moving plate, 28: screw shaft, 30: driving source 32: Z-axis guide rail, 34: second moving plate, 36: screw shaft, 38: driving source 40: Cutting unit, 42: Spindle housing 44: Spindle, 46: Cutting blade 48: Microscope camera unit 50: Laser displacement meter (displacement meter), 50a: Head part 52: Touch panel display 54: Controller, 54a: Processor, 54b: Memory A1, A2, A3: point, C: center, D: depth, d: length, L: length La: Line laser Position:X1,X2 S10: Holding step, S20: Cutting groove forming step, S30: Depth measuring step S40: Calculation step, S50: Three-dimensional image creation step, S60: Determination step r: radius, θ: angle

Claims

1. A method for measuring the size of a cutting blade in a processing device that processes a workpiece with a cutting blade, comprising: a holding step of holding the workpiece on a holding table; a cutting groove forming step of cutting the cutting blade into the upper surface of the workpiece held by the holding table to form a cutting groove in the upper surface of the workpiece; a depth measuring step of measuring the depth of the cut groove at a plurality of locations in the longitudinal direction of the cut groove while moving a head portion of a displacement meter provided above the cut groove and the holding table holding the workpiece relatively along the longitudinal direction of the cut groove; a calculation step of calculating a size of the cutting blade based on the depths of the cutting grooves at a plurality of positions in the longitudinal direction; A measuring method comprising:

2. In the depth measuring step, depths of the cut groove at a plurality of locations in the longitudinal direction are measured at each of a plurality of positions in a predetermined direction perpendicular to the longitudinal direction in a plan view; 2. The measuring method according to claim 1, further comprising a three-dimensional image creating step of creating a three-dimensional image of the cut groove based on data on the depth of the cut groove obtained in the depth measuring step.

3. 3. The measuring method according to claim 2, further comprising a determining step of determining whether the tip shape of the cutting blade is good or bad based on the shape of a region in the three-dimensional image that corresponds to the opening of the cutting groove.

4. The upper surface of the holding table has a rectangular shape, In the holding step, a rectangular substrate corresponding to the shape of the upper surface of the holding table is held as the workpiece; 4. The measuring method according to claim 1, wherein in the kerf forming step, the kerf is formed in the workpiece held by the holding table.

5. a holding table for holding the workpiece; a cutting unit having a spindle and configured to cut the workpiece with a cutting blade attached to a tip of the spindle; a displacement meter having a head portion provided above the holding table and configured to measure the depth of a cutting groove formed on the upper surface of the workpiece by the cutting blade; a controller having a processor and a memory, and controlling the operations of the holding table, the cutting unit, and the displacement meter; Equipped with The controller measures the depth of the cutting groove at multiple points in the longitudinal direction of the cutting groove while moving the head of the displacement meter and the holding table holding the workpiece relatively along the longitudinal direction of the cutting groove, and calculates the size of the cutting blade based on the depth of the cutting groove at multiple points in the longitudinal direction.

6. the controller measures depths of the cut groove at a plurality of locations in the longitudinal direction with the displacement meter at each of a plurality of positions in a predetermined direction perpendicular to the longitudinal direction in a plan view; 6. The processing device according to claim 5, wherein a three-dimensional image of the cut groove is created based on data on the depth of the cut groove in the longitudinal direction and the predetermined direction.

7. 7. The processing device according to claim 6, wherein the controller determines whether the tip shape of the cutting blade is good or bad based on the shape of a region in the three-dimensional image that corresponds to the opening of the cutting groove.

8. 8. The processing apparatus according to claim 5, wherein the holding table is a disk-shaped first holding table, or a second holding table that is disposed adjacent to the first holding table and has a shape different from that of the first holding table in a plan view.

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