Cutting device and workpiece cutting method

Abstract

To cut a workpiece with high quality by removing chips stuck to a cutting grindstone of a cutting blade.SOLUTION: This cutting device for cutting a workpiece comprises: a chuck table that holds the workpiece; and a cutting unit to which a cutting blade including an annular cutting grindstone for cutting the workpiece held on the chuck table can be rotatably fitted. The cutting blade includes a first nozzle for spraying a cleaning fluid to one side surface of the fitted cutting blade, and a second nozzle for spraying the cleaning fluid to the other side surface of the cutting blade. Inlets for spraying the cleaning fluid are formed in the first and second nozzles, and the cleaning fluid is a mixed fluid containing both water and gas.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a cutting device that includes a chuck table that holds a workpiece, and a cutting unit that can be fitted with a cutting blade that cuts the workpiece held by the chuck table. [Background technology]

[0002] In the device chip manufacturing process, devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are formed in multiple regions on the front surface of a wafer defined by multiple intersecting division lines (streets). The wafer is then divided along the division lines to obtain multiple device chips, each equipped with a device. The device chips are then installed in electronic devices such as mobile terminals and personal computers.

[0003] A cutting device is used to divide the wafers (see Patent Document 1). The cutting device includes a chuck table that holds the workpiece, and a cutting unit to which a cutting blade equipped with an annular cutting stone is attached. The cutting unit includes a rotation drive mechanism that rotates the attached cutting blade. When cutting the workpiece with the cutting device, the cutting blade is rotated, and the cutting stone of the rotating cutting blade cuts into the workpiece.

[0004] When a workpiece is cut with a cutting blade, cutting chips and heat are generated from the workpiece and the cutting blade. Therefore, in a cutting device, cutting water made of pure water or the like is supplied to the cutting blade and the workpiece while the workpiece is being cut. In particular, cutting water is supplied to the cutting wheel of the cutting blade from the outer periphery toward the outer periphery. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-75558 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, the quality standards required for chips manufactured by dividing wafers have been increasing. Accordingly, the adhesion of chips of a size that was not a major problem in the past has become a problem. Furthermore, the deterioration of cutting quality due to the debris that adheres and remains on the annular side of the cutting wheel of the cutting blade has become a problem. In particular, when debris with a small particle size adheres to the side of the cutting wheel, it cannot be sufficiently removed by the cutting water supplied to the outer surface of the cutting wheel.

[0007] Furthermore, when a workpiece (wafer) is cut with a cutting blade that has chips attached to the side of the cutting wheel, the chips come into contact with the workpiece, separate from the cutting wheel, and adhere to the devices formed in the workpiece, thereby reducing the quality of the chips formed by dividing the workpiece.

[0008] Furthermore, to maintain the cutting ability of the cutting wheel, the cutting blade is periodically subjected to a process called dressing. In dressing, the cutting wheel of the cutting blade is cut into a component called a dressing board. This dressing board contains metals such as aluminum and nickel. Therefore, the dressing generates chips containing these metals, which adhere to the side of the cutting wheel of the cutting blade. When a workpiece is cut with a cutting blade with metal-containing chips attached to the cutting wheel, the chips adhere to the workpiece and become a source of contamination, causing problems.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a cutting device and a method for cutting a workpiece that can remove debris adhering to the cutting wheel of a cutting blade and cut the workpiece with high quality. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided a cutting device for cutting a workpiece, comprising: a chuck table for holding the workpiece; and a cutting unit to which a cutting blade equipped with an annular cutting wheel for cutting the workpiece held by the chuck table can be rotatably attached, the cutting unit including a first nozzle for spraying a cleaning fluid onto one side of the attached cutting blade, and a second nozzle for spraying the cleaning fluid onto the other side of the cutting blade, the first nozzle and the second nozzle each having an injection port for spraying the cleaning fluid, and the cleaning fluid is a mixed fluid containing both water and gas.

[0011] Preferably, the jets are oriented in a direction between horizontal and vertical.

[0012] According to another aspect of the present invention, there is provided a method for cutting a workpiece using a cutting device that includes a chuck table for holding a workpiece, and a cutting unit to which a cutting blade equipped with an annular cutting stone for cutting the workpiece held by the chuck table can be attached, the cutting unit including a first nozzle for spraying a cleaning fluid onto one side of the attached cutting blade, and a second nozzle for spraying the cleaning fluid onto the other side of the cutting blade, the first nozzle and the second nozzle each having an ejection port for ejecting the cleaning fluid, the ejection port facing a direction between a horizontal direction and a vertical direction, A method for cutting a workpiece is provided, comprising: a dressing step for dressing the cutting wheel of the cutting blade; a cleaning step for cleaning the cutting wheel by spraying the cleaning fluid from the nozzle of the first nozzle onto one side of the cutting wheel and spraying the cleaning fluid from the nozzle of the second nozzle onto the other side of the cutting wheel; and a cutting step for cutting the workpiece held on the chuck table with the cutting blade attached to the cutting unit after the cleaning step, wherein the cleaning step is performed simultaneously with the dressing step, between the dressing step and the cutting step, or simultaneously with the cutting step.

[0013] Preferably, the cleaning fluid is a mixed fluid containing both water and gas.

[0014] More preferably, the jets are oriented in a direction between horizontal and vertical. [Effects of the Invention]

[0015] In a cutting device and a method for cutting a workpiece according to one aspect of the present invention, a cleaning fluid is sprayed from the nozzles of the first and second nozzles to clean the side of a cutting blade attached to a cutting unit. In particular, this cleaning fluid is a mixed fluid containing both water and gas, so it has extremely high cleaning power. This actively removes debris adhering to the side of the cutting wheel of the cutting blade. This allows for high-quality cutting of the workpiece without causing problems due to debris.

[0016] Therefore, one aspect of the present invention provides a cutting device and a method for cutting a workpiece that can remove debris adhering to the cutting wheel of a cutting blade and cut the workpiece with high quality. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a perspective view schematically showing a cutting device. [Figure 2] FIG. 2 is a perspective view schematically showing a cutting unit. [Figure 3] FIG. 2 is an exploded perspective view schematically illustrating a configuration of a part of a cutting unit. [Figure 4] FIG. 2 is a perspective view schematically showing a first nozzle and a second nozzle of the cutting unit. [Figure 5] FIG. 10 is a side view schematically showing a state in which a cleaning fluid is sprayed onto a cutting grindstone of a cutting blade. [Figure 6] FIG. 6(A) is a side view schematically showing a first example of dressing of a cutting blade, and FIG. 6(B) is a side view schematically showing a second example of dressing of a cutting blade. [Figure 7] FIG. 10 is a side view schematically showing how the outer periphery of the workpiece is cut. [Figure 8] FIG. 10 is a side view schematically showing a state in which the workpiece is cut along the planned dividing lines. [Figure 9] 3 is a flowchart showing the flow of each step of a method for machining a workpiece. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, a cutting device and a workpiece cutting method for cutting a workpiece with the cutting device cut a workpiece such as a semiconductor wafer with a cutting blade.

[0019] First, the workpiece will be described. Fig. 7 includes a cross-sectional view that schematically shows workpiece 17. Workpiece 17 is, for example, a disk-shaped wafer made of a semiconductor material such as silicon, and has a circular front surface 17a and a circular back surface 17b facing the opposite side to front surface 17a.

[0020] A plurality of planned dividing lines arranged in a grid pattern so as to intersect with one another are set on the surface 17a of the workpiece 17. Devices such as ICs and LSIs are formed in each of the regions defined by the planned dividing lines on the surface 17a of the workpiece 17.

[0021] For example, workpiece 17 is ground from the back surface 17b side to thin workpiece 17, and then divided along the planned division lines to produce a plurality of thin chips (device chips), each equipped with a device. The manufactured device chips are mounted in various electronic devices such as mobile phones and personal computers.

[0022] There are no limitations on the material, structure, size, etc. of the workpiece 17. For example, the workpiece 17 may be a substrate made of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), sapphire, glass (quartz glass, borosilicate glass, etc.), etc. The workpiece 17 does not have to be disk-shaped, and may be, for example, a plate-like structure with rectangular front and back surfaces. There are also no limitations on the type, number, shape, structure, size, arrangement, etc. of devices, and the workpiece 17 does not have to have any devices formed thereon.

[0023] In order to prevent chipping or cracking from the edge of the workpiece 17, the outer periphery 17c of the workpiece 17 is chamfered in advance. That is, the outer periphery 17c of the workpiece 17 is formed with a chamfered portion having an arc-shaped cross section.

[0024] If workpiece 17 with chamfered outer periphery 17c is ground directly from back surface 17b, a knife-edge shape where part of the chamfer is cut off appears on outer periphery 17c, making chipping and cracking more likely. Therefore, before grinding, outer periphery 17c of workpiece 17 is cut from front surface 17a to remove the chamfer. This process is called edge trimming.

[0025] Furthermore, when dividing the ground and thinned workpiece 17 along the planned dividing lines, the workpiece 17 is cut along the planned dividing lines. A cutting device is used for edge trimming and dividing the workpiece 17. When the workpiece 17 is carried into the cutting device, the workpiece 17 is integrated with the adhesive tape 13 and the annular frame 15 as shown in FIG. 8 to form a frame unit. The workpiece 17 is carried into the cutting device in the form of a frame unit and processed.

[0026] The frame unit includes an annular frame 15 and adhesive tape 13 attached so as to cover an opening of frame 15. Adhesive tape 13 is attached to the back surface 17b of workpiece 17 at a position overlapping the opening of frame 15. In other words, workpiece 17 is supported by frame 15 via adhesive tape 13.

[0027] In this state, when the workpiece 17 is divided along the planned division lines, the individual chips formed are still supported by the frame 15 via the adhesive tape 13. Therefore, when the frame unit is formed, the workpiece 17 and the chips can be easily handled.

[0028] Next, a cutting device according to this embodiment will be described. Fig. 1 is a perspective view that schematically shows the appearance of a cutting device 2 that cuts a workpiece 17. Note that the X-axis, Y-axis, and Z-axis used in the description of this cutting device 2 are perpendicular to one another.

[0029] The cutting device 2 has an exterior 4 that covers each component. A cassette support table 6 is provided in one corner that is not covered by the exterior 4. A cassette (not shown) that stores a plurality of workpieces 17 is mounted on the upper surface of the cassette support table 6.

[0030] The inside of the exterior 4 of the cutting device 2 is a processing chamber. The cutting device 2 cuts a workpiece 17 in the processing chamber. A chuck table (holding table) 8 capable of holding the workpiece 17 by suction is housed in the processing chamber. The cutting device 2 also includes a cutting unit 10 in the processing chamber that cuts the workpiece 17 held by the chuck table 8. For example, the cutting device 2 includes two cutting units 10, one of which is shown schematically in FIG. 1.

[0031] The chuck table 8 is moved in the processing feed direction (X-axis direction) by a processing feed unit (X-axis movement mechanism) not shown. The cutting unit 10 is moved in the index feed direction by an index feed unit (Y-axis movement mechanism) not shown. The cutting unit 10 is moved in the cutting feed direction by a cutting feed unit (Z-axis movement mechanism) not shown. The chuck table 8 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis that is approximately parallel to the Z-axis direction (vertical direction).

[0032] 6(A) and the like include a cross-sectional view schematically showing the chuck table 8. The chuck table 8 includes a disk-shaped frame 58 having a recess exposed upward, and a disk-shaped porous member 60 housed in the recess of the frame 58. The porous member 60 has a diameter equal to that of the workpiece 17. A suction path (not shown) connected to a suction source (not shown) such as an ejector is formed inside the chuck table 8.

[0033] The chuck table 8 also includes a plurality of clamps 62 that secure the annular frame 15 integrated with the workpiece 17 via adhesive tape 13. The clamps 62 clamp and secure the frame 15 integrated with the workpiece 17 placed on the chuck table 8.

[0034] When the workpiece 17 is placed on the upper surface of the chuck table 8, the frame 15 is clamped with the clamps 62, and the negative pressure generated by the suction source is applied to the workpiece 17 through the suction path and the porous member 60, the workpiece 17 can be sucked and held by the chuck table 8. The upper surface of the chuck table 8 is formed approximately parallel to the horizontal plane and serves as the holding surface.

[0035] FIG. 2 is a perspective view that schematically shows the cutting unit 10, and FIG. 3 is an exploded perspective view that schematically shows some of the components of the disassembled cutting unit 10. A cutting blade 38 equipped with an annular cutting wheel 40 is rotatably attached to the cutting unit 10. The cutting blade 38 is covered by a blade cover 42. The cutting unit 10 cuts the workpiece 17 by rotating the cutting blade 38 and bringing it into contact with the workpiece 17. The cutting unit 10 will be described in detail below.

[0036] First, the components covered by the blade cover 42 will be mainly described. The cutting unit 10 includes a spindle housing 12 connected to an indexing feed unit (not shown) of the cutting device 2 or the like. As shown in Fig. 3, a spindle 14 is rotatably supported in the spindle housing 12 along the indexing feed direction (Y-axis direction). The tip (front end) of the spindle 14 protrudes forward from the spindle housing 12.

[0037] A rear flange 18 is attached to the tip of the spindle 14. A threaded hole 16 is formed in the tip of the spindle 14, into which a bolt 26 is fastened. An insertion hole 24 extending from the rear to the front is formed in the rear flange 18. When the rear flange 18 is fixed to the spindle 14, the spindle 14 is inserted into this insertion hole 24 from the rear side of the rear flange 18. Then, when the bolt 26 is fastened into the threaded hole 16 at the tip of the spindle 14 via a washer 28, the rear flange 18 is fixed to the spindle 14.

[0038] The rear flange 18 includes a flange portion 20 extending radially outward, and a boss portion 22 protruding forward from the surface (front surface) of the flange portion 20. The outer peripheral surface of the flange portion 20 forms an abutment surface 30 that abuts against the rear side surface of the cutting blade 38. This abutment surface 30 is formed in an annular shape when viewed from the axial direction (Y-axis direction) of the spindle 14. The boss portion 22 is formed in a cylindrical shape, and a screw thread 32 is provided on its outer peripheral surface.

[0039] As described below, a circular through hole 40a is formed in the center of the cutting blade 38, through which the boss portion 22 is inserted, and the cutting blade 38 is attached to the rear flange 18 by inserting the boss portion 22 into this through hole 40a.

[0040] The front flange 34 has a flange portion extending radially outward, and the back surface of the outer circumferential side of this flange portion serves as an abutment surface that abuts against the side surface on the front side of the cutting blade 38. This abutment surface is formed in an annular shape when viewed from the axial direction (Y-axis direction) of the spindle 14. The front flange 34 has an opening 34a that is inserted into the boss portion 22 of the rear flange 18.

[0041] The front flange 34 is attached to the rear flange 18 so that the boss portion 22 passes through the opening 34a, the cutting blade 38 is sandwiched between the front flange 34 and the rear flange 18, and the fixing nut 36 that fixes the front flange 34 is tightened to the boss portion 22. In this manner, the cutting blade 38 is attached to the cutting unit 10.

[0042] Here, the cutting blade 38 will be described. Figure 3 includes a perspective view that schematically shows the cutting blade 38. The cutting blade 38 shown in Figure 3 and other figures is, for example, a cutting blade called a washer type, which is made up of an annular cutting wheel 40. However, the cutting blade 38 attached to the cutting unit 10 is not limited to the washer type. The cutting blade 38 may also be a hub blade having an annular base to which the cutting wheel 40 is fixed on the outer periphery.

[0043] The cutting stone 40 of the cutting blade 38 has a binder made of resin, metal, or the like, and diamond abrasive grains dispersed in the binder, and is formed in a circular ring shape with a through hole 40a in the center. When the cutting blade 38 is attached to the cutting unit 10 and rotated around an axis along the penetration direction of the through hole 40a and brought into contact with the workpiece 17, the workpiece 17 is cut.

[0044] 2, a blade cover 42 is provided on the front surface of the spindle housing 12 to house the cutting blade 38 and other components attached to the spindle 14. The blade cover 42 is provided with an outlet 48 for supplying water to the workpiece 17. The outlet 48 is connected to a connector 46 provided on the blade cover 42, and water supplied through the connector 46 is ejected from the outlet.

[0045] When the workpiece 17 is cut by the cutting blade 38, cutting chips are generated and scattered onto the workpiece 17. In addition, processing heat is generated due to friction between the cutting blade 38 and the workpiece 17. Therefore, when cutting the workpiece 17 with the cutting blade 38, water is supplied to the workpiece 17 as cutting fluid from the nozzle 48, and the cutting chips and heat are absorbed into the cutting fluid and removed.

[0046] Furthermore, the blade cover 42 may be provided with a jetting port (not shown) for supplying water from the outer circumferential direction to the cutting wheel 40 of the cutting blade 38. When water is jetted from this jetting port onto the cutting wheel 40, the outer circumferential surface 40b of the cutting wheel 40 is cleaned.

[0047] Additionally, a pair of generally L-shaped nozzles 50a, 50b are fixed to the blade cover 42, sandwiching the lower part of the cutting blade 38 from the front and rear. More specifically, the cutting unit 10 includes a first nozzle 50a that sprays cleaning fluid onto one side surface 40c of the attached cutting blade 38, and a second nozzle 50b that sprays cleaning fluid onto the other side surface 40d of the cutting blade 38.

[0048] The first nozzle 50a and the second nozzle 50b are connected to the tip side of a feed pipe (not shown) provided inside the blade cover 42, and a connector 44 is provided at the base end side of this feed pipe. A pipe leading to a supply source of a cleaning fluid is connected to the connector 44.

[0049] 4 is a perspective view schematically showing the first nozzle 50a and the second nozzle 50b of the cutting unit 10. The first nozzle 50a and the second nozzle 50b are each formed with a plurality of jetting orifices 52 for jetting the cleaning fluid. The cleaning fluid and the jetting orifices 52 will be described in detail below.

[0050] In recent years, the quality standards required for chips manufactured by dividing a workpiece 17 such as a wafer have been increasing. Accordingly, the adhesion of debris of a size that previously did not pose a significant problem to chips has become a problem. For example, debris with an average particle size of 30 nm to 200 nm has become a problem. When such debris, particularly with a small particle size, adheres to the annular side surfaces 40c and 40d of the cutting wheel 40 of the cutting blade 38, it cannot be adequately removed by the cutting fluid supplied to the outer peripheral surface 40b of the cutting wheel 40.

[0051] When the workpiece 17 (wafer) is cut with the cutting blade 38 having chips attached to the side surfaces 40c, 40d of the cutting wheel 40, the chips attached to the cutting wheel 40 come into contact with the workpiece 17, separate from the cutting wheel 40, and adhere to the device formed in the workpiece 17. As a result, the chips reduce the quality of the chips formed by dividing the workpiece 17.

[0052] Furthermore, to maintain the cutting ability of the cutting wheel 40, the cutting blade 38 is periodically subjected to a process called dressing. In dressing, the cutting wheel 40 of the cutting blade 38 is cut into a member called a dressing board. This dressing board contains metals such as aluminum and nickel. Therefore, dressing generates chips containing these metals, which adhere to the side surfaces 40c, 40d of the cutting wheel 40 of the cutting blade 38. When the cutting blade 38 with chips containing metal attached to the cutting wheel 40 cuts the workpiece 17, the chips adhere to the workpiece 17 and become a source of contamination, causing problems.

[0053] Therefore, in the cutting device according to this embodiment, cleaning fluid is ejected from the nozzles 52 of the first nozzle 50a and the second nozzle 50b to clean the side surfaces of the cutting blade 38 attached to the cutting unit 10.

[0054] In particular, the cleaning fluid is a mixed fluid (two-fluid) containing both water and gas (e.g., air). An additive such as a surfactant may be added to the cleaning fluid. Furthermore, a high-pressure gas with a pressure exceeding 1 atmosphere may be used as the gas.

[0055] Fig. 5 is a plan view schematically showing the cutting blade 38, the first nozzle 50a, and the second nozzle 50b as viewed from the front, which are attached to the cutting unit 10. Fig. 5 shows how the cleaning fluid 56 is supplied from the first nozzle 50a and the second nozzle 50b to the side surfaces 40c, 40d of the cutting wheel 40 of the cutting blade 38.

[0056] In particular, in the cutting device 2 according to this embodiment, the nozzles 52 of the first nozzle 50a and the second nozzle 50b are preferably oriented in a direction between the horizontal and vertical directions. In Fig. 5, the direction 54 of the nozzle 52 is indicated by a dashed line. Note that the direction 54 of the nozzle 52 is, for example, the direction of the center line of the travel range of the cleaning fluid 56 ejected from the nozzle 52. Alternatively, the direction 54 of the nozzle 52 is a direction perpendicular to a plane including the nozzle 52.

[0057] When the cleaning fluid 56 containing water and high-pressure gas is sprayed onto the side surfaces 40c, 40d of the cutting wheel 40 of the cutting blade 38, the debris adhering to the side surfaces 40c, 40d can be actively removed. Therefore, the cutting blade 38 can cut the workpiece 17 with high quality without causing problems due to the debris.

[0058] The cleaning of the cutting blade 38 with the cleaning fluid 56 may be performed simultaneously with the cutting of the workpiece 17 by the cutting blade 38, or may be performed after the completion of cutting one workpiece 17 and while the cutting of the next workpiece 17 is being performed. Also, the cleaning may be performed after dressing the cutting blade 38 with a dressing board and before cutting the workpiece 17.

[0059] Next, a method for cutting the workpiece 17 will be described as a method for using the cutting device 2 configured as described above. FIG. 9 is a flowchart illustrating the flow of each step of the method for cutting the workpiece using the cutting device 2. In this method for cutting the workpiece, after the cutting blade 38 is attached to the cutting unit 10 of the cutting device 2, the cutting wheel 40 of the cutting blade 38 is dressed. Then, after the cutting wheel 40 is cleaned, the cutting blade 38 is used to cut the workpiece 17.

[0060] In the method for cutting a workpiece shown in Fig. 9, first, a dressing step S10 is performed in which the cutting wheel 40 of the cutting blade 38 attached to the cutting unit 10 is dressed. Fig. 6(A) is a side view schematically showing the state in which the cutting wheel 40 is dressed in the dressing step S10 according to the first example. Fig. 6(A) includes a side view schematically showing a partial configuration of the cutting unit 10. Fig. 6(A) also includes a cross-sectional view schematically showing the chuck table 8 and the like.

[0061] In the dressing step S10, a dressing board 11 is used. The dressing board 11 is manufactured by fixing abrasive grains made of, for example, green carborundum (GC) made of silicon carbide (SiC) or white alundum (WA) with a binder such as resin or ceramics, and forming it into a flat plate with a thickness of about 1 mm. A filler may be mixed into the binder. By cutting the dressing board 11 with the cutting blade 38, the cutting wheel 40 is actively worn down, and the shape and condition of the cutting wheel 40 are adjusted.

[0062] The dressing board 11 is fixed to an annular frame 15 via adhesive tape 13 and transported to the chuck table 8 so that it can be handled in the same way as the workpiece 17 in the cutting device 2. When the dressing board 11 is placed on the chuck table 8, the frame 15 is fixed with a clamp 62, and the suction source connected to the chuck table 8 is activated, the dressing board 11 is held by suction on the chuck table 8.

[0063] 6(A), the cutting unit 10 and the chuck table 8 are moved relatively to each other, and the lowest end of the cutting wheel 40 of the cutting blade 38 is positioned outside the dressing board 11. Then, while rotating the cutting blade 38, the cutting unit 10 and the chuck table 8 are moved relatively along the processing feed direction (X-axis direction), and the rotating cutting wheel 40 is caused to cut into the dressing board 11.

[0064] When the cutting wheel 40 is cut into the dressing board 11, the cutting wheel 40 is worn down appropriately, the shape of the cutting wheel 40 is adjusted, and abrasive grains are exposed appropriately on the surface of the cutting wheel 40, improving the condition of the cutting wheel 40. In particular, the condition of the outer peripheral surface 40b of the cutting wheel 40 becomes suitable for cutting the workpiece 17. At this time, chips and heat are generated from the cutting wheel 40 and the dressing board 11. Therefore, when cutting the dressing board 11 with the cutting wheel 40, cutting fluid may be supplied from the cutting unit 10.

[0065] Next, the dressing step S10 according to the second example will be described. Fig. 6(B) is a side view schematically showing the state in which the cutting wheel 40 is dressed in the dressing step S10 according to the second example. Fig. 6(B) includes a side view schematically showing a part of the configuration of the cutting unit 10. Fig. 6(B) also includes a cross-sectional view schematically showing the chuck table 8 and the like.

[0066] In the dressing step S10 according to the second example, the dressing board 11 is also held by suction on the chuck table 8. Then, as shown in FIG. 6(B), the cutting unit 10 and the chuck table 8 are moved relative to each other to position the very bottom end of the cutting wheel 40 of the cutting blade 38 outside the dressing board 11. At this time, the very bottom end of the cutting wheel 40 is positioned at a height position slightly lower than the upper surface of the dressing board 11.

[0067] Then, while rotating the cutting blade 38, the cutting unit 10 and the chuck table 8 are moved relatively along the indexing feed direction (Y-axis direction) to cause the rotating cutting wheel 40 to cut into the dressing board 11. When the cutting wheel 40 cuts into the dressing board 11, the shape and condition of the cutting wheel 40 are adjusted. In particular, in the dressing step S10 according to the second example, the shape of the corner where the outer peripheral surface 40b and the side surfaces 40c, 40d of the cutting wheel 40 connect is adjusted, i.e., the roundness of the corner is reduced. For this reason, the dressing process performed in the dressing step S10 according to the second example is also called flat dressing.

[0068] The debris generated by performing the dressing step S10 according to the first or second example also adheres to the side surfaces 40c, 40d of the cutting wheel 40. The debris adhered to the side surfaces 40c, 40d of the cutting wheel 40 is not sufficiently removed by the cutting fluid. In particular, in the flat dressing performed in the dressing step S10 according to the second example, a large amount of debris is likely to adhere to the side surfaces 40c, 40d of the cutting wheel 40. Therefore, the cleaning step S20 is performed after the dressing step S10.

[0069] Next, the cleaning step S20 will be described. Fig. 5 is a plan view schematically showing the cutting blade 38 being cleaned with the cleaning fluid 56 in the cleaning step S20. The cleaning step S20 is performed, for example, with the cutting unit 10 and the like moved so that the chuck table 8 and the cutting unit 10 do not overlap. This makes it difficult for the debris removed from the cutting wheel 40 to reach the chuck table 8 or the workpiece 17 held by the chuck table 8.

[0070] Alternatively, the cleaning step S20 is performed when the workpiece 17 is not held by the chuck table 8. This makes it difficult for the debris removed from the cutting wheel 40 to reach the workpiece 17.

[0071] In the cleaning step S20, cleaning fluid 56 is sprayed from the nozzle 52 of the first nozzle 50a onto one side surface 40c of the cutting wheel 40, and cleaning fluid 56 is sprayed from the nozzle 52 of the second nozzle 50b onto the other side surface 40d of the cutting wheel 40. This cleans the cutting wheel 40, particularly the side surfaces 40c and 40d. By rotating the cutting blade 38 at this time, the side surfaces 40c and 40d of the cutting wheel 40 are cleaned with the cleaning fluid 56 all around.

[0072] Here, in the cleaning step S20, it is not necessary for the cleaning fluid 56 to directly hit the entire area of ​​the side surfaces 40c, 40d of the cutting wheel 40. In the cleaning step S20, it is preferable for the cleaning fluid 56 to hit the side surfaces 40c, 40d of the cutting wheel 40 in an area that comes into contact with or approaches the workpiece 17 when cutting the workpiece 17. If debris is removed from the cutting wheel 40 in this area, the debris is less likely to be a problem when the cutting blade 38 cuts the workpiece 17, and the cutting blade 38 can cut the workpiece 17 with high quality.

[0073] In addition, in the cleaning step S20, structures other than the cutting wheel 40 of the cutting blade 38 may be cleaned. For example, if the cutting blade 38 is a hub blade and includes an annular base with the cutting wheel 40 fixed to its outer periphery, the cleaning fluid 56 may be sprayed onto the annular base, and the annular base may be cleaned with the cleaning fluid 56. Furthermore, the cleaning fluid 56 may be sprayed onto the front flange 34, rear flange 18, etc. to which the cutting blade 38 is fixed, and the front flange 34, rear flange 18, etc. may be cleaned with the cleaning fluid 56.

[0074] If debris adheres to the front flange 34, rear flange 18, the annular base of the cutting blade 38, or the like, the debris may fall onto the workpiece 17 during, before, or after cutting the workpiece 17 and adhere to the workpiece 17. If the front flange 34, etc., are washed with the washing fluid 56 in the washing step S20, such a problem does not occur, and the workpiece 17 can be cut with high quality.

[0075] In the method of cutting the workpiece 17 in the cutting device 2, after the cleaning step S20, a cutting step S30 is performed in which the workpiece 17 held on the chuck table 8 is cut with a cutting blade 38 attached to the cutting unit 10.

[0076] Fig. 7 is a cross-sectional view schematically showing the workpiece 17 when performing the cutting step S30 according to the first example. Fig. 7 includes a cross-sectional view schematically showing the workpiece 17 such as a semiconductor wafer. In the cutting step S30 according to the first example shown in Fig. 7, the cutting unit 10 performs edge trimming to remove in advance a chamfered portion formed on the outer periphery 17c of the workpiece 17 to be thinned by grinding.

[0077] In cutting step S30, workpiece 17 is placed on chuck table 8. Workpiece 17 is oriented such that front surface 17a on which devices and the like are formed faces upward and back surface 17b faces downward. The position of workpiece 17 is adjusted so that the center of workpiece 17 coincides with the center of the upper surface (holding surface) of chuck table 8. Thereafter, workpiece 17 is suction-held by chuck table 8. Note that workpiece 17 does not have to be supported by frame 15 via adhesive tape 13, and may be placed directly on chuck table 8.

[0078] Next, in cutting step S30, the cutting unit 10 and the chuck table 8 are moved relative to each other, and the cutting wheel 40 of the cutting blade 38 is positioned above the outer periphery 17c of the workpiece 17 held by the chuck table 8. Next, the cutting blade 38 is lowered while rotating, and the cutting wheel 40 cuts into the outer periphery 17c of the workpiece 17. At this time, the lower end of the cutting wheel 40 is positioned at a height position that is greater than the finishing thickness of the workpiece 17 to be thinned and lower than the surface 17a of the workpiece 17.

[0079] Thereafter, while continuing to rotate the cutting blade 38, the chuck table 8 is rotated one or more times around the rotation axis intersecting the holding surface. As a result, the workpiece 17 is cut along the outer periphery 17c by the cutting blade 38, and the chamfered portion is removed. When the workpiece 17 from which the chamfered portion has been removed is ground from the back surface 17b side to be thinned, a knife-edge shape resulting from the chamfered portion is not formed on the outer periphery 17c of the workpiece 17, and therefore cracking, damage, etc. of the workpiece 17 is suppressed.

[0080] Next, the cutting step S30 according to the second example will be described. Fig. 8 is a cross-sectional view schematically showing the workpiece 17 when the cutting step S30 according to the second example is performed. Fig. 8 includes a cross-sectional view schematically showing the workpiece 17 such as a semiconductor wafer. In the cutting step S30 according to the second example shown in Fig. 8, the workpiece 17, which has been thinned by grinding, is cut and divided along the planned division lines by the cutting unit 10.

[0081] In the cutting step S30, the thinned workpiece 17 is placed on the chuck table 8, and the chuck table 8 holds the workpiece 17 by suction. At this time, the workpiece 17 is preferably supported on the frame 15 via the adhesive tape 13. In this case, when the workpiece 17 is divided into individual chips, the chips are supported by the adhesive tape 13, making it easy to handle the chips.

[0082] Next, in cutting step S30, the cutting unit 10 and the chuck table 8 are moved relative to each other, and the cutting wheel 40 of the cutting blade 38 is positioned on an extension of the planned dividing line of the workpiece 17 held by the chuck table 8. Next, the cutting blade 38 is lowered while being rotated, and the lower end of the cutting wheel 40 is positioned at a height slightly lower than the lower surface of the workpiece 17.

[0083] Thereafter, the chuck table 8 and the cutting unit 10 are moved relatively along the processing feed direction (X-axis direction) while continuing to rotate the cutting blade 38. As a result, the workpiece 17 is cut along the intended division line by the cutting blade 38, and a division groove is formed.

[0084] After cutting the workpiece 17 along one planned dividing line, the cutting blade 38, etc. is moved in the indexing feed direction to cut the workpiece 17 along the other planned dividing lines. After cutting the workpiece 17 along all planned dividing lines in one direction, the chuck table 8 is rotated to switch the processing feed direction, and the workpiece 17 is cut along the planned dividing lines in the other direction. When cutting the workpiece 17 along all planned dividing lines in this way is completed, individual chips are produced.

[0085] When the cutting device 2 according to this embodiment cuts the workpiece 17 with the cutting blade 38 that has been cleaned in advance with the cleaning fluid 56, problems caused by debris adhering to the side surfaces 40c, 40d of the cutting wheel 40 are unlikely to occur. Therefore, whether the workpiece 17 is subjected to edge trimming or cut along the planned dividing line, the cutting device 2 according to this embodiment can perform high-quality cutting.

[0086] In particular, when edge trimming is performed in cutting step S30 to cut workpiece 17 along outer periphery 17c, it is preferable that a mixed fluid (two-fluid) formed by mixing water and gas (air) is used as cleaning fluid 56 in cleaning step S20. When this two-fluid is used as cleaning fluid 56 to clean cutting wheel 40, it is possible to remove small particles that have not been a problem in the past, and therefore cutting wheel 40 can be cleaned more effectively.

[0087] When edge trimming is performed with the cutting device 2, a cutting blade 38 equipped with a cutting wheel 40 having a relatively large cutting thickness (width) is used to cut the workpiece 17 along the outer periphery 17c at a predetermined width. That is, the cutting blade 38 used for edge trimming generally has a thicker cutting wheel 40 than the cutting blade 38 used for cutting the workpiece 17 along the planned division line to obtain multiple chips.

[0088] For example, a cutting blade 38 with a blade thickness (thickness of the cutting wheel 40) of about 100 μm is used to cut the workpiece 17 along the planned dividing line. On the other hand, a cutting blade 38 with a blade thickness of 1 mm to 3 mm is used for edge trimming. The cutting wheel 40 of the cutting blade 38 with such a large thickness has relatively high strength against impacts on the side surfaces 40c, 40d. Therefore, when cleaning a cutting wheel 40 with a large blade thickness, the cleaning fluid 56 can be sprayed onto the cutting wheel 40 using a mixed fluid under high-intensity spraying conditions.

[0089] However, a mixed fluid (two-fluid) may also be used as the cleaning fluid 56 for cleaning the cutting blade 38 that cuts the workpiece 17 along the planned dividing line. As long as the conditions are such that adverse effects such as chipping or vibration are not caused on the cutting wheel 40, the cutting wheel 40 can be efficiently cleaned by spraying the mixed fluid onto the side surfaces 40c, 40d.

[0090] As described above, in the cutting device 2 and the method for cutting the workpiece 17 according to this embodiment, the cleaning fluid 56 is ejected from the nozzles 52 of the first nozzle 50a and the second nozzle 50b to clean the side surfaces of the cutting blade 38 attached to the cutting unit 10. This makes it possible to actively remove debris adhering to the side surfaces 40c, 40d of the cutting grindstone 40 of the cutting blade 38. Therefore, the workpiece 17 can be cut with high quality without causing problems due to debris.

[0091] In the above embodiment, the case where the cutting wheel 40 of the cutting blade 38 is dressed before cutting the workpiece 17 with the cutting blade 38 has been described. However, in the cutting device 2 and the method for cutting the workpiece 17 according to one aspect of the present invention, the cutting wheel 40 does not need to be dressed before cutting the workpiece 17.

[0092] When the cutting wheel 40 of the cutting blade 38 is dressed, multiple workpieces 17 can be cut by the cutting blade 38 before the condition of the cutting wheel 40 deteriorates to a state unsuitable for cutting. Therefore, after cutting of one workpiece 17 is completed, cutting of the next workpiece 17 may be performed without dressing the cutting blade 38.

[0093] In other words, after the dressing step S10 and the cleaning step S20 are performed and the cutting step S30 for cutting the workpiece 17 is performed, another cutting step S30 for cutting another workpiece 17 may be performed. In further other words, after the dressing step S10 and the cleaning step S20 are performed, another cutting step S30 for cutting another workpiece 17 may be performed before the cutting step S30 for cutting the workpiece 17 is performed.

[0094] Even in these cases, each of the workpieces 17 is cut with high quality by the cutting wheel 40 that has been cleaned by spraying the cleaning fluid 56 onto the side surfaces 40c, 40d. Therefore, each of the workpieces 17 benefits from the cleaning effect of the cleaning fluid 56.

[0095] In the above embodiment, the cutting blade 38 is cleaned with the cleaning fluid 56 between the dressing of the cutting blade 38 and the cutting of the workpiece 17, but one aspect of the present invention is not limited to this. Cleaning of the cutting wheel 40 of the cutting blade 38 with the cleaning fluid 56 may be performed simultaneously with dressing of the cutting wheel 40 of the cutting blade 38, or may be performed simultaneously with cutting of the workpiece 17 by the cutting blade 38.

[0096] In these cases, debris and heat generated from the dressing board 11 or the workpiece 17 and the cutting wheel 40 are removed by the cleaning fluid 56. In other words, since the cleaning fluid 56 functions as a cutting fluid, the amount of cutting fluid supplied to the cutting wheel 40, etc. separately from the cleaning fluid 56 can be reduced.

[0097] 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. [Explanation of symbols]

[0098] 11 Dressing Board 13 Adhesive tape 15 frames 17 Workpiece 17a surface 17b Back side 17c outer periphery 2 Cutting equipment 4. Exterior 6 Cassette support stand 8 Chuck table 10 Cutting unit 12 Spindle housing 14 Spindle 16 screw holes 18 Rear flange 20 flange 22 Boss section 24 Insertion hole 26 volts 28 Washer 30 Contact surface 32 threads 34 Front flange 34a aperture 36 Fixing nut 38 Cutting Blade 40 Cutting Wheel 40a through hole 40b Outer surface 40c,40d side 42 Blade cover 44,46 Connector 48 spout 50a, 50b nozzle 52 Nozzle 54 Orientation 56 Cleaning fluid 58 Frame 60 Porous material 62 Clamp

Claims

1. A cutting device for cutting a workpiece, a chuck table for holding the workpiece; a cutting unit capable of rotatably mounting a cutting blade having an annular cutting stone for cutting the workpiece held by the chuck table, the cutting unit includes a first nozzle for spraying a cleaning fluid onto one side surface of the attached cutting blade, and a second nozzle for spraying the cleaning fluid onto the other side surface of the cutting blade; The first nozzle and the second nozzle each have an ejection port through which the cleaning fluid is ejected, The cleaning fluid is a mixed fluid containing both water and gas.

2. 2. The cutting device according to claim 1, wherein the injection port is oriented in a direction between a horizontal direction and a vertical direction.

3. A method for cutting a workpiece using a cutting device comprising: a chuck table for holding a workpiece; and a cutting unit to which a cutting blade equipped with an annular cutting wheel for cutting the workpiece held by the chuck table can be attached, the cutting unit including a first nozzle for spraying a cleaning fluid onto one side of the attached cutting blade, and a second nozzle for spraying the cleaning fluid onto the other side of the cutting blade, the first nozzle and the second nozzle each having an ejection port for ejecting the cleaning fluid, the ejection port facing a direction between a horizontal direction and a vertical direction, a dressing step of dressing the cutting wheel of the cutting blade attached to the cutting unit; a cleaning step of cleaning the cutting wheel by spraying the cleaning fluid from the injection port of the first nozzle onto one side surface of the cutting wheel and spraying the cleaning fluid from the injection port of the second nozzle onto the other side surface of the cutting wheel; a cutting step of cutting the workpiece held by the chuck table with the cutting blade attached to the cutting unit after the cleaning step, The method for cutting a workpiece, wherein the cleaning step is carried out simultaneously with the dressing step, between the dressing step and the cutting step, or simultaneously with the cutting step.

4. 4. The method for cutting a workpiece according to claim 3, wherein the cleaning fluid is a mixed fluid containing both water and gas.

5. 5. The method for cutting a workpiece according to claim 3, wherein the injection port is oriented in a direction between the horizontal and vertical directions.

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