JP2019000933A - Grinding device - Google Patents

Abstract

An object of the present invention is to provide a grinding device that can determine whether or not burrs exist on the outer peripheral edge of a protective tape before grinding a workpiece. [Solution] A grinding device that grinds a plate-shaped workpiece with a protective tape affixed to one side, which detects burrs on the outer periphery of the protective tape before carrying the workpiece to a chuck table. The burr detection unit includes an imaging section that images an area including a part of the outer periphery of the workpiece and a part of the outer periphery of the protective tape to form an image; a determination unit that determines whether or not a burr exists on the outer periphery of the protective tape from information included in the image, and the determination unit determines whether or not there is a burr on the outer periphery of the workpiece and the protective tape calculated from the image. When the distance from the outer circumferential edge of the masking tape exceeds a preset threshold value or is equal to or greater than the threshold value, it is determined that a burr exists on the outer circumferential edge of the protective tape. [Selection diagram] Figure 1

Description

  The present invention relates to a grinding apparatus used when grinding a plate-like workpiece.

  In order to reduce the size and weight of device chips incorporated in various electronic devices and the like, there are increasing opportunities to thinly process a wafer before being divided into device chips. For example, the wafer surface can be thinned by holding the wafer side with a chuck table and pressing a rotated grinding wheel (grinding tool) against the back side of the wafer. Reference 1).

  When grinding the back side of the wafer by the method as described above, a protective tape is usually applied to the front side of the wafer (see, for example, Patent Document 2). Thereby, it is possible to prevent the device on the surface side from being damaged by a force applied during grinding. For example, the protective tape is attached to the front surface side of the wafer using a dedicated device, and then cut with a cutter or the like along the outer peripheral edge of the wafer.

JP 2000-288888 A JP 2015-26769 A

  However, when the protective tape affixed to a workpiece such as a wafer is cut by the method described above, protrusions called burrs are generated on the outer peripheral edge of the protective tape depending on the sharpness of the cutter. When a work piece is ground in a state where burrs are present on the protective tape, the work piece may not be properly ground because the burr is caught in the gap between the grinding wheel and the work piece.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a grinding apparatus capable of determining whether or not burrs are present on the outer peripheral edge of the protective tape before grinding the workpiece. Is to provide.

  According to one aspect of the present invention, a chuck table that holds the protective tape side of a plate-like workpiece having a protective tape affixed on one surface thereof, and the other of the workpieces held on the chuck table A grinding unit for grinding the surface, a loading unit for holding the workpiece and carrying it into the chuck table, and removing the burrs on the outer peripheral edge of the protective tape before carrying the workpiece into the chuck table. A burr detection unit for detecting, and the burr detection unit forms an image by imaging a region including a part of the outer peripheral edge of the workpiece and a part of the outer peripheral edge of the protective tape. And a determination unit that determines whether or not there is a burr on the outer periphery of the protective tape from information included in the image formed by the imaging unit, and the determination unit is calculated from the image The outer peripheral edge of the workpiece and the protective tape When the distance between the outer peripheral edge of the protective tape exceeds a preset threshold value or when the distance exceeds the predetermined threshold value, it is determined that there is a burr on the outer peripheral edge of the protective tape. .

  In one aspect of the present invention, the image processing apparatus may further include a center position detection unit that detects a position of the center of the workpiece held by the carry-in unit, and the imaging unit may also serve as a part of the center position detection unit. good.

  In one aspect of the present invention, a center position adjusting unit that adjusts the position of the center of the workpiece held by the carry-in unit may be further provided.

  A grinding apparatus according to an aspect of the present invention is formed by an imaging unit that images an area including a part of an outer peripheral edge of a workpiece and a part of an outer peripheral edge of a protective tape, and an imaging unit. A determination unit for determining whether or not there is a burr on the outer peripheral edge of the protective tape from information included in the image, and before transferring the workpiece to the chuck table, It is equipped with a burr detection unit.

  The determination unit of this burr detection unit protects when the distance between the outer peripheral edge of the workpiece calculated from the image and the outer peripheral edge of the protective tape exceeds a preset threshold value or is equal to or greater than this threshold value. It is determined that there are burrs on the outer periphery of the tape. Therefore, according to the grinding apparatus which concerns on 1 aspect of this invention, before carrying a workpiece into a chuck table and grinding with a grinding unit, it can be determined whether a burr | flash exists in the outer periphery of a protective tape.

It is a perspective view which shows the structural example of a grinding apparatus typically. It is a perspective view which shows typically the structural examples, such as a to-be-processed object. It is a figure which shows the example of the image formed with the camera.

  Embodiments according to one aspect of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a configuration example of a grinding apparatus 2 according to the present embodiment. As shown in FIG. 1, the grinding device 2 includes a base 4 that supports each component.

  An opening 4a is formed on the front end side of the upper surface of the base 4, and a first transport unit 6 for transporting the workpiece 11 (see FIG. 2) is provided in the opening 4a. . Further, support bases 10a and 10b for supporting cassettes 8a and 8b that can accommodate a plurality of workpieces 11 are provided in a region further forward of the opening 4a.

  FIG. 2 is a perspective view schematically showing a configuration example of the workpiece 11 and the like. As shown in FIG. 2, the workpiece 11 is a disk-shaped wafer made of a material such as silicon (Si). The surface (one surface) 11a side of the workpiece 11 is divided into a plurality of areas by division lines (streets) 13 arranged in a lattice pattern. Each area includes an IC (Integrated Circuit) or the like. The device 15 is formed.

  In the present embodiment, a disk-shaped wafer made of a material such as silicon is used as the workpiece 11. However, the material, shape, structure, size, etc. of the workpiece 11 are not limited. It is also possible to use a workpiece 11 made of other materials such as semiconductors, ceramics, resins, and metals. Similarly, the type, quantity, shape, structure, size, arrangement, etc. of the device 15 are not limited.

  A protective film 21 having the same diameter as that of the workpiece 11 is attached to the surface 11 a side of the workpiece 11. The protective film 21 is made of a resin such as polyethylene (PE) or polyethylene terephthalate (PET), and is cut along the outer peripheral edge 11c of the workpiece 11 using a cutter or the like. That is, the outer peripheral edge 21 a of the protective film 21 substantially overlaps the outer peripheral edge 11 c of the workpiece 11.

  As shown in FIG. 1, a detection unit (center position detection unit, burr detection unit) 12 used when detecting the center position of the workpiece 11 is provided obliquely behind the opening 4a. The detection unit 12 includes, for example, a holding table 14 that temporarily holds the workpiece 11 conveyed by the first conveying unit 6 from the cassettes 8a and 8b, and a camera (imaging unit) 16 adjacent to the holding table 14. Contains.

  The holding table 14 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the vertical direction (Z-axis direction). The camera 16 images the workpiece 11 held on the holding table 14 to form an image, and sends the image to the processing unit 18. The processing unit 18 calculates the center position of the workpiece 11 from the image formed by the camera 16. The detection unit 12 may form an image using light emitted from below the workpiece 11, or form an image using light emitted from above the workpiece 11. You may do it.

  At a position adjacent to the detection unit 12, a second transport unit 20 that sucks, holds and holds the workpiece 11 is provided. The second transport unit 20 includes, for example, a suction pad 20 a that can suck the entire back surface (the other surface) 11 b of the workpiece 11, and the workpiece 11 whose center position is detected by the detection unit 12. Transport backwards.

  A disc-shaped turntable 22 is disposed behind the second transport unit 20. Three chuck tables 24 for sucking and holding the workpiece 11 are provided on the upper surface of the turntable 22 at approximately equal angular intervals. Each chuck table 24 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the vertical direction.

  A part of the upper surface of each chuck table 24 is a holding surface that sucks and holds the surface 11a side (protective tape 21) of the workpiece 11. The holding surface is connected to a suction source (not shown) via a suction path (not shown) formed inside the chuck table 24. The workpiece 11 is sucked and held by the chuck table 24 by applying the negative pressure of the suction source to the holding surface.

  The turntable 20 is connected to a rotational drive source (not shown) such as a motor, and rotates around a rotation axis that is substantially parallel to the vertical direction. By rotating the turntable 20, each chuck table 24 can be positioned at any of the carry-in / out position, the rough grinding position, and the finish grinding position, for example. However, the number of chuck tables 24 provided on the upper surface of the turntable 22 may be two or less, or four or more.

  The workpiece 11 unloaded from the detection unit 12 by the second transfer unit 20 is loaded into the chuck table 24 positioned at the loading / unloading position. At this time, the second transport unit 20 is configured to align the center of the workpiece 11 with the center of the chuck table 24 based on the information on the center of the workpiece 11 detected by the detection unit 12. 11 is carried into the chuck table 24.

  Two support structures 26 are provided behind the turntable 22. A Z-axis moving mechanism 28 is provided on the front surface of each support structure 26. The Z-axis moving mechanism 28 includes a pair of Z-axis guide rails 30 fixed to the front surface of the support structure 26 and substantially parallel to the vertical direction. A Z-axis moving plate 32 is slidably attached to the Z-axis guide rail 30.

  A nut portion (not shown) is provided on the rear surface (back surface) side of the Z-axis moving plate 32, and a Z-axis ball screw 34 parallel to the Z-axis guide rail 30 is screwed into the nut portion. . A Z-axis pulse motor 36 is connected to one end of the Z-axis ball screw 34. When the Z-axis ball screw 34 is rotated by the Z-axis pulse motor 36, the Z-axis moving plate 32 moves in the vertical direction along the Z-axis guide rail 30.

  A support 38 is fixed to the front surface (surface) of the Z-axis moving plate 32. A grinding unit 40 for grinding the workpiece 11 is supported on the support tool 38. The grinding unit 40 includes a spindle housing 42 supported by a support tool 38. The spindle housing 42 accommodates a spindle 44 that serves as a rotation axis substantially parallel to the vertical direction.

  A lower end portion of the spindle 44 is exposed to the outside of the spindle housing 42. A disc-shaped wheel mount 46 is fixed to the lower end portion of the spindle 44, and a grinding wheel 48 having a diameter substantially the same as that of the wheel mount 46 is attached to the lower surface of the wheel mount 46. A rotation drive source (not shown) such as a motor is connected to the upper end side of the spindle 44, and the grinding wheel 48 is rotated by a force transmitted from the rotation drive source.

  Here, a grinding wheel 48 for rough grinding is mounted on the grinding unit 40 close to the rough grinding position. A grinding wheel 48 for finish grinding is mounted on the grinding unit 40 close to the finish grinding position. A plurality of grinding wheels are provided on the lower surface side of each grinding wheel 48.

  After the workpiece 11 is loaded onto the chuck table 24 at the loading / unloading position, the turntable 22 is rotated to position the chuck table 24 at the rough grinding position. Then, the grinding unit 40 is lowered in a state where the chuck table 24 and the grinding wheel 48 for rough grinding are both rotated, and the grinding wheel is brought into contact with the back surface 11 b of the workpiece 11. Thereby, the workpiece 11 is roughly ground.

  After the workpiece 11 is roughly ground, the turntable 22 is rotated to position the chuck table 24 at the finish grinding position. Then, the grinding unit 40 is lowered while the chuck table 24 and the grinding wheel 48 for finish grinding are both rotated, and the grinding wheel is brought into contact with the upper surface of the workpiece 11. Thereby, the workpiece 11 is finish-ground. Note that after the workpiece 11 is finish-ground, the turntable 22 is rotated to position the chuck table 24 at the loading / unloading position.

  At a position adjacent to the second transport unit 20, a third transport unit 50 that sucks, holds, and turns the workpiece 11 is provided. The third transport unit 50 includes, for example, a suction pad 50a that can suck the entire back surface 11b side of the workpiece 11, and transports the workpiece 11 held on the chuck table 24 at the loading / unloading position forward. .

  A cleaning unit 52 that cleans the ground workpiece 11 that has been transported by the third transport unit 50 is disposed in front of the third transport unit 50 and obliquely behind the opening 4a. The workpiece 11 cleaned by the cleaning unit 52 is transported by the first transport unit 6 and accommodated in the cassettes 8a and 8b.

  When the workpiece 11 is ground with the grinding apparatus 2 configured as described above, if a burr (protrusion) is present on the outer peripheral edge 21a of the protective tape 21, the grinding wheel 48 (grinding wheel) and the workpiece are processed. In some cases, burrs are caught in the gap between the workpiece 11 and the workpiece 11 cannot be properly ground. Therefore, in the grinding device 2 of this embodiment, the burr (presence or absence of burr) of the outer peripheral edge 21a of the protective tape 21 is carried out before the workpiece 11 is carried into the chuck table 24 using the detection unit 12 described above. To detect.

  The method for detecting burrs is, for example, as follows. First, the workpiece 11 to which the protective tape 21 is attached is placed on the holding table 14 by the first transport unit 6 or the like. Next, an area including a part of the outer peripheral edge 11 c of the workpiece 11 and a part of the outer peripheral edge 21 a of the protective tape 21 is imaged by the camera 16 to form an image. In the present embodiment, an image is formed on the entire periphery of the workpiece 11 and the protective tape 21 by taking an image with the camera 16 while rotating the protective tape 21. FIG. 3 is a diagram illustrating an example of an image 31 formed by the camera 16.

  For example, the workpiece 11 made of a material such as silicon hardly transmits visible light, but the protective tape 21 made of resin or the like transmits visible light. Further, for example, the workpiece 11 made of a material such as silicon strongly reflects visible light, but the protective tape 21 made of resin or the like does not reflect visible light so strongly.

  The calculation unit 18a of the processing unit 18 utilizes the difference in optical properties between the workpiece 11 and the protective tape 21 from the inside of the image 31, and the outer peripheral edge 11c of the workpiece 11 and the protective tape 21. The outer peripheral edge 21a is extracted. Specifically, for example, the outer peripheral edge 11 c of the workpiece 11 and the outer peripheral edge 21 a of the protective tape 21 are extracted by a method such as edge detection using the difference in brightness of each pixel in the image 31.

  After extracting the outer peripheral edge 11 c of the workpiece 11 from the image 31, the calculation unit 18 a calculates the position of the center of the workpiece 11. The calculated position of the center of the workpiece 11 is also used when the center of the workpiece 11 is aligned with the center of the chuck table 24 as described above. Thus, in the present embodiment, detection of the center of the workpiece 11 and detection of burrs are performed simultaneously.

  After calculating the center position of the workpiece 11, the calculation unit 18 a calculates the distance D between the outer peripheral edge 11 c of the workpiece 11 and the outer peripheral edge 21 a of the protective tape 21. Here, the intersection point between an arbitrary straight line passing through the center of the workpiece 11 and the outer peripheral edge 11c and the distance between the straight line and the outer peripheral edge 21a are obtained as the distance D. By obtaining the distance D along an arbitrary straight line passing through the center of the workpiece 11, the burr of the protective tape 21 can be appropriately evaluated. In the present embodiment, the distance D is obtained at a plurality of positions along the outer peripheral edge 11 c of the workpiece 11 and the outer peripheral edge 21 a of the protective tape 21.

  After calculating the distance D at a plurality of positions, the determination unit 18 b of the processing unit 18 determines whether or not there is a burr on the outer peripheral edge 21 a of the protective tape 21. Specifically, the determination unit 18b compares the distance D between the outer peripheral edge 11c of the workpiece 11 and the outer peripheral edge 21a of the protective tape 21 calculated by the calculation unit 18a with a predetermined threshold value. . When any distance D calculated at a plurality of positions exceeds the threshold (or when the distance D is greater than or equal to the threshold), the determination unit 18b determines that there is a burr on the outer peripheral edge 21a of the protective tape 21. .

  On the other hand, when all the distances D calculated at a plurality of positions are equal to or smaller than the threshold value (or when the distance D is less than the threshold value), the determination unit 18b has no burr on the outer peripheral edge 21a of the protective tape 21. Is determined. The determination result is notified to, for example, a control unit (not shown) that controls the entire grinding apparatus 2. Thereafter, the control unit notifies the operator of the determination result by an arbitrary method. Examples of the notification method include generation of a warning sound, lighting (flashing) of a warning light, display on a monitor, and the like.

  The control unit may change the operation of each component based on the determination result. For example, the workpiece 11 determined to have burrs on the outer peripheral edge 21a of the protective tape 21 may be accommodated again in the cassettes 8a and 8b by the first transport unit 6 or the like without being ground. .

  As described above, the grinding apparatus 2 according to the present embodiment forms an image 31 by capturing an area including a part of the outer peripheral edge 11 c of the workpiece 11 and a part of the outer peripheral edge 21 a of the protective tape 21. A camera (imaging unit) 16, and a determination unit 18 b that determines whether or not a burr exists on the outer peripheral edge 21 a of the protective tape 21 from information included in the image 31 formed by the camera 16. Before carrying 11 into the chuck table 24, a detection unit (burr detection unit) 12 for detecting burrs on the outer peripheral edge 21a of the protective tape 21 is provided.

  The determination unit 18b of the detection unit 12 determines whether the distance D between the outer peripheral edge 11c of the workpiece 11 and the outer peripheral edge 21a of the protective tape 21 calculated from the image 31 exceeds a preset threshold value or When it is equal to or greater than the threshold value, it is determined that a burr exists on the outer peripheral edge of the protective tape 21. Therefore, according to this grinding device 2, it is possible to determine whether or not there is a burr on the outer peripheral edge 21a of the protective tape 21 before the workpiece 11 is carried into the chuck table 24 and ground by the grinding unit 40.

  In addition, this invention is not restrict | limited to description of the said embodiment, A various change can be implemented. For example, in the above-described embodiment, the grinding device 2 that performs detection of the center position of the workpiece 11 and detection of burrs of the protective tape 21 by the detection unit 12 has been described, but the center position of the workpiece 11 is described. The center position detection unit that detects burrs and the burr detection unit that detects burrs on the protective tape 21 may be separated.

  Further, instead of the center position detection unit that detects the center position of the workpiece 11, a center position adjustment unit that directly adjusts the center position of the workpiece 11 may be provided. For example, the center position of the workpiece 11 is adjusted by using a center position adjusting unit that moves along the radial direction of the workpiece 11 and includes a plurality of claws (regulating members) that define the position of the outer peripheral edge 11c. It can be adjusted directly.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

2 Grinding device 4 Base 4a Opening 6 First transport unit 8a, 8b Cassette 10a, 10b Support base 12 Detection unit (center position detection unit, burr detection unit)
14 Holding table 16 Camera (imaging part)
DESCRIPTION OF SYMBOLS 18 Processing part 18a Arithmetic part 18b Judgment part 20 2nd conveyance unit 20a Suction pad 22 Turntable 24 Chuck table 26 Support structure 28 Z-axis moving mechanism 30 Z-axis guide rail 32 Z-axis moving plate 34 Z-axis ball screw 36 Z-axis pulse motor DESCRIPTION OF SYMBOLS 38 Support tool 40 Grinding unit 42 Spindle housing 44 Spindle 46 Wheel mount 48 Grinding wheel 50 Third conveyance unit 50a Suction pad 52 Cleaning unit 11 Workpiece 11a Surface (one surface)
11b Back side (the other side)
11c Outer rim 13 Scheduled line (street)
15 device 21 protective tape 21a outer peripheral edge

Claims (3)

A chuck table for holding the protective tape side of a plate-like workpiece having a protective tape affixed to one surface;
A grinding unit for grinding the other surface of the workpiece held on the chuck table;
A loading unit that holds the workpiece and loads the workpiece into the chuck table;
A burr detection unit that detects a burr on the outer peripheral edge of the protective tape before carrying the workpiece into the chuck table;
The burr detection unit is
An imaging unit that forms an image by imaging a region including a part of the outer peripheral edge of the workpiece and a part of the outer peripheral edge of the protective tape;
A determination unit that determines whether or not there is a burr on the outer peripheral edge of the protective tape from information included in an image formed by the imaging unit;
The determination unit is configured to detect the protection when the distance between the outer peripheral edge of the workpiece and the outer peripheral edge of the protective tape calculated from the image exceeds a preset threshold value or more than the threshold value. A grinding apparatus characterized by determining that burrs are present on an outer peripheral edge of a tape. A center position detection unit for detecting the position of the center of the workpiece held by the carry-in unit;
The grinding apparatus according to claim 1, wherein the imaging unit also serves as a part of the center position detection unit.   The grinding apparatus according to claim 1, further comprising a center position adjusting unit that adjusts a position of a center of the workpiece held by the carry-in unit.