Cutting device

Abstract

To provide a cutting device that can prevent cutting liquid including chips from adhering to a work-piece.SOLUTION: The cutting device is provided with: a holding table (12) that holds a work-piece (1) on a holding surface (13); a rotatable cutting blade (53); cutting liquid supply nozzles (55 and 56) that supply cutting liquid (M) to a processing point (K) at which the cutting blade cuts into the work-piece; a moving unit (20) that moves the holding table in a processing / feeding direction (X); a cover plate (70) having a clearance formed from the processing point to a rear side (Xb) in the feeding / processing direction to cover an upper surface (2) of the work-piece, which is arranged adjacently to the cutting blade: and a liquid supply unit (80) that supplies liquid (P) through a liquid supply hole (81) formed on a lower surface of the cover plate to form a liquid layer (PS) between the lower surface of the cover plate and the upper surface of the work-piece.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cutting device for cutting a workpiece.

Background Art

[0002] In a cutting device that cuts a workpiece such as a wafer with a cutting blade, the workpiece is cut while supplying cutting fluid to the cutting point where the cutting blade contacts the workpiece, and the cutting chips generated by the processing are discharged from the workpiece. At that time, if the cutting fluid (contaminated fluid) mixed with the cutting chips adheres to the surface of the workpiece, there is a problem that the workpiece and the devices formed on the workpiece are contaminated.

[0003] Patent Document 1 describes a structure for preventing the cutting fluid supplied to the cutting point from entering the inside of the cutting device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The invention of Patent Document 1 aims to prevent the contaminated fluid from entering the moving mechanism and the like that moves the holding table around the holding table that holds the workpiece, and does not achieve the prevention of the adhesion of the contaminated fluid to the surface of the workpiece.

[0006] Regarding the prevention of the adhesion of the contaminated fluid to the workpiece, there is a known countermeasure of protecting the workpiece from the contaminated fluid by continuously flowing a clean fluid on the surface of the workpiece. However, a huge amount of fluid was required to protect the workpiece from the contaminated fluid that scatters with great force.

[0007] Another known solution involves installing a suction duct at a position behind the machining feed direction in the rotational direction of the cutting blade, thereby instantly sucking up the contaminating liquid. However, this requires installing suction equipment outside the cutting device, resulting in a large and complex setup.

[0008] The present invention has been made in view of the above, and aims to provide a cutting device that prevents cutting fluid containing cutting chips from adhering to the workpiece. [Means for solving the problem]

[0009] One aspect of the present invention is a cutting apparatus comprising: a holding table having a holding surface for holding a workpiece; a cutting blade rotatably fixed to the tip of a spindle; a cutting fluid supply nozzle for supplying cutting fluid to a cutting point where the cutting blade cuts into the workpiece held on the holding surface; and a moving unit for moving the holding table in the machining feed direction, It is plate-shaped and has a lower surface along the holding surface, A gap is provided so as to cover the top surface of the workpiece, and 、 The cutting blade In contrast, at predetermined intervals behind the machining point in the machining feed direction A cover plate is installed adjacent to the cover plate, and the cover plate Applicable Liquid is supplied through one or more liquid supply holes formed on the bottom surface of the cover plate. Applicable The lower surface and the workpiece Applicable The present invention further comprises a liquid supply unit that forms a layer of liquid between itself and the upper surface.

[0010] The cover plate is preferably installed with a gap of 2 mm to 10 mm from the retaining surface.

[0011] Preferably, the cover plate has a length equal to or greater than the diameter of the holding surface in the indexing feed direction perpendicular to the machining feed direction.

[0012] Preferably, the cover plate is formed with a slope that descends toward the rear in the processing feed direction. Furthermore, it is preferable that the liquid supply hole is located towards the front of the cover plate in the processing feed direction. [Effects of the Invention]

[0013] According to the cutting device of the present invention, the cover plate and the liquid supply unit can prevent the cutting fluid containing cutting chips from adhering to the workpiece.

Brief Description of the Drawings

[0014] [Figure 1] It is a perspective view of the cutting device of the present embodiment. [Figure 2] It is a perspective view of the holding table and its peripheral structure in the cutting device. [Figure 3] It is a perspective view of the holding table and its peripheral structure with the cover plate removed. [Figure 4] It is a side view of the cutting unit. [[ID=2,2]] [Figure 5] It is a cross-sectional view near the holding table along the machining feed direction. [Figure 6] It is a cross-sectional view near the holding table along the indexing feed direction. [Figure 7] It is a cross-sectional view near the inclined portion of the cover plate along the machining feed direction.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, the cutting device according to the present embodiment will be described with reference to the accompanying drawings. The cutting device 10 shown in FIG. 1 cuts a workpiece 1. The workpiece 1 is, for example, a disk-shaped semiconductor wafer made of silicon or the like. On the surface 2 side of the workpiece 1, chips 3, which are electronic devices, are formed in a plurality of regions partitioned by a plurality of grid-like division planned lines. A flexible tape 4 is attached to the back side of the workpiece 1, and an annular ring frame 5 is attached to the outer peripheral portion of the tape 4.

[0016] Note that the workpiece cut by the cutting device 10 is not limited to a semiconductor wafer, and may be an inorganic material substrate such as ceramic, glass, or sapphire, or a package substrate of a semiconductor product.

[0017] In the cutting device 10, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The X-axis direction and Y-axis direction are horizontal directions, and the Z-axis direction is the vertical direction. The X-axis direction is the machining feed direction for relatively moving the workpiece 1 and the cutting blade 53 described later when performing cutting along the planned division line. The arrow Xa side in the figure is the front, and the arrow Xb side is the rear. The Y-axis direction is the indexing feed direction for relatively moving the workpiece 1 and the cutting blade 53 in order to position the cutting blade 53 at the next planned division line after the cutting of the planned division line. The Z-axis direction is the cutting feed direction for relatively moving the workpiece 1 and the cutting blade 53 when the cutting blade 53 cuts into the workpiece 1.

[0018] The cutting device 10 includes a holding table 12 on a base 11. The holding table 12 has a holding surface 13 formed of a porous member such as a porous ceramic material on the upper surface side, and a suction force can be applied to the holding surface 13 by a suction source (not shown). The workpiece 1 is suction-held on the holding surface 13 of the holding table 12 through the tape 4 by the suction force on the holding surface 13 (see FIGS. 5 and 6). A plurality of clamps 14 are provided around the holding table 12, and the ring frame 5 around the workpiece 1 is clamped and fixed by the clamps 14 (see FIG. 5).

[0019] On the base 11 of the cutting device 10, a moving unit 20 for machining feed that moves the holding table 12 in the X-axis direction is provided. The moving unit 20 has a pair of guide rails 21 arranged on the base 11 and extending in the X-axis direction, and a ball screw 22 provided between the pair of guide rails 21 and extending in the X-axis direction. The ball screw 22 is rotationally driven by a drive motor 23 provided at one end. The X-axis moving table 24 is supported so as to be slidable in the X-axis direction with respect to the guide rails 21 and has a screwing portion (not shown) with which the ball screw 22 is screwed. When the drive motor 23 rotates the ball screw 22, the X-axis moving table 24 moves in the X-axis direction.

[0020] A rotation support section 25 is provided on the X-axis moving table 24, which rotatably supports the holding table 12 around the Z-axis axis. The holding table 12 is supported on the upper part of the rotation support section 25, and the holding table 12 can be rotated by a drive motor (not shown) provided in the rotation support section 25. The holding table 12 is detachable from the rotation support section 25.

[0021] A column 15 is erected on the upper surface of the base 11, to the side of the moving unit 20 in the Y-axis direction. The column 15 is equipped with an indexing feed mechanism 30 for moving the cutting unit 50 in the Y-axis direction (indexing feed) and a lifting mechanism 40 for moving the cutting unit 50 in the Z-axis direction (cutting feed).

[0022] The indexing feed mechanism 30 includes a pair of guide rails 31 positioned on the front of the column 15 and extending in the Y-axis direction, and a ball screw 32 provided between the pair of guide rails 31 and extending in the Y-axis direction. The ball screw 32 is rotationally driven by a drive motor (not shown) provided at one end. The Y-axis moving table 33 is supported so as to be slidable in the Y-axis direction relative to the guide rails 31 and has a threaded portion (not shown) into which the ball screw 32 is screwed. When the ball screw 32 is rotated by the drive motor, the Y-axis moving table 33 moves in the Y-axis direction.

[0023] The lifting mechanism 40 includes a pair of guide rails 41 positioned in front of the Y-axis moving table 33 and extending in the Y-axis direction, and a ball screw 42 supported by the Y-axis moving table 33 and extending in the Z-axis direction. The ball screw 42 is rotationally driven by a drive motor 43 provided at one end. The Z-axis moving table 44 is supported so as to be slidable in the Z-axis direction relative to the guide rails 41 and has a threaded portion (not shown) into which the ball screw 42 is screwed. When the ball screw 42 is rotated by the drive motor 43, the Z-axis moving table 44 moves in the Z-axis direction.

[0024] The cutting unit 50 includes a spindle motor (not shown) in a spindle housing 51 supported at the lower end of the Z-axis moving table 44, and the spindle 52 rotates about an axis extending in the Y-axis direction when driven by the spindle motor.

[0025] As shown in Figure 4, an annular cutting blade 53 is fixed to the tip of the spindle 52. A blade cover 54 surrounding the cutting blade 53 is attached to the end of the spindle housing 51. The blade cover 54 has an upper cover 541 located above the cutting blade 53 in the Z-axis direction, a front cover 542 located forward Xa in the X-axis direction relative to the cutting blade 53, and a rear cover 543 located backward Xb in the X-axis direction relative to the cutting blade 53. The blade cover 54 is shaped to leave the lower part of the cutting blade 53 exposed without covering it.

[0026] A shower nozzle 55 is provided near the lower end of the front cover 542, which sprays cutting fluid M toward the rear Xb in the X-axis direction. The shower nozzle 55 is positioned opposite a portion of the outer circumference of the cutting blade 53 in the X-axis direction, and the cutting fluid M is sprayed from the shower nozzle 55 toward the cutting blade 53. More specifically, the cutting fluid M is sprayed from the shower nozzle 55 toward a position below the rotation center of the spindle 52 relative to the cutting blade 53.

[0027] A blade cooler 56 extends from the rear cover 543. The blade cooler 56 is a tubular member with a channel formed inside for passing cutting fluid M, and has an L-shape that extends downward in the Z-axis direction from the front cover 542 and then bends forward towards the Xa side in the X-axis direction. The blade cooler 56 has a cooler nozzle 561 that opens in the Y-axis direction toward the side of the cutting blade 53, and the cutting fluid M that has passed through the blade cooler 56 is ejected from the cooler nozzle 561 toward the side of the cutting blade 53 in the Y-axis direction. More specifically, the cutting fluid M is ejected from the cooler nozzle 561 toward a position below the rotation center of the spindle 52 toward the cutting blade 53.

[0028] The blade coolers 56 may be positioned on both sides of the cutting blade 53 in the Y-axis direction. In this case, cutting fluid M can be ejected from the blade coolers 56 on both sides in the Y-axis direction toward both sides of the cutting blade 53.

[0029] The cutting apparatus 10 is equipped with a cutting fluid tank 57 for storing cutting fluid M, and the shower nozzle 55 and blade cooler 56 are connected to the cutting fluid tank 57 via a cutting fluid supply passage 58. When the pump (not shown) is driven, the cutting fluid M is sent from the cutting fluid tank 57 to the cutting fluid supply passage 58, and the cutting fluid M is ejected from the shower nozzle 55 and blade cooler 56 (cooler nozzle 561). The cutting fluid M can be, for example, pure water or a liquid containing a surfactant in pure water.

[0030] In the cutting device 10, the cutting blade 53 is rotated by the spindle 52, and the workpiece 1 is cut by cutting the workpiece 1 from the surface 2 side in the Z-axis direction with the cutting blade 53. The point where the cutting blade 53 cuts into the workpiece 1 is the machining point K (Figure 5).

[0031] During machining, cutting fluid M is supplied to the machining point K and its surroundings by the shower nozzle 55 and the blade cooler 56. In other words, the shower nozzle 55 and the blade cooler 56 (cooler nozzle 561) are cutting fluid supply nozzles that supply cutting fluid M to the machining point K. Note that both the shower nozzle 55 and the blade cooler 56 may be provided as cutting fluid supply nozzles, or only one of the shower nozzle 55 or the blade cooler 56 may be provided.

[0032] Each part of the cutting device 10 is controlled by the control unit 16 (Figure 1). The control unit 16 uses a processor to perform various calculations according to a control program stored in the memory unit, and transmits operation signals to each part of the cutting device 10 to execute its operation.

[0033] The cutting of the workpiece 1 in the cutting device 10 is performed as follows. The operation of each part of the cutting device 10 is controlled by the control unit 16, and unless otherwise specified, the operation is performed based on the control of the control unit 16.

[0034] A transport mechanism (not shown in the diagram) carries the workpiece 1 to the holding table 12 while holding the ring frame 5. The workpiece 1 is placed on the holding surface 13 via the tape 4, and a suction force is applied to the holding surface 13 with the surface 2 of the workpiece 1 facing upwards. In other words, the workpiece 1 is held on the holding table 12 with the surface 2 facing upwards. The ring frame 5 is also fixed by the clamp 14. As a result, the workpiece 1 is held on the holding table 12, as shown in Figures 5 and 6.

[0035] The control unit 16 adjusts the relative positions of the holding table 12 and the cutting blade 53 in the X-axis and Y-axis directions using the moving unit 20 and the indexing feed mechanism 30, positioning the cutting blade 53 above the rear Xb end of the division line that is to be cut. Subsequently, the control unit 16 drives the spindle motor to rotate the spindle 52 and the cutting blade 53 at a predetermined speed, and moves the cutting unit 50 downward in the Z-axis direction using the lifting mechanism 40. The cutting blade 53 rotates and cuts into the workpiece 1 held on the holding table 12 at the machining point K.

[0036] In the cutting device 10, the cutting blade 53 is rotated at a fixed position, and the holding table 12 (the X-axis moving table 24 that supports the holding table 12) is moved (machining feed) by the moving unit 20 to the rear Xb side in the X-axis direction, thereby performing cutting along the planned division line extending in the X-axis direction. In other words, the planned division line on the workpiece 1 is cut from the rear Xb side to the front Xa side in the X-axis direction. Figure 5 shows the state after cutting has been performed up to near the end of the planned division line.

[0037] Once cutting along one planned division line is complete, the control unit 16 stops the rotation of the spindle 52 and moves the cutting unit 50 upward in the Z-axis direction using the lifting mechanism 40, moving the cutting blade 53 away from the workpiece 1. Next, the control unit 16 moves the holding table 12 back to the forward Xa side in the X-axis direction using the moving unit 20, and moves the Y-axis moving table 33 in the Y-axis direction using the indexing feed mechanism 30 (indexing feed), positioning the cutting blade 53 above the rear Xb end of the next uncut planned division line. Then, similarly to the above, the spindle motor is driven to rotate the spindle 52 and cutting blade 53 at a predetermined speed, the cutting blade 53 is moved downward in the Z-axis direction using the lifting mechanism 40 (cutting feed), and the holding table 12 is moved to the rear Xb side in the X-axis direction using the moving unit 20 (machining feed), performing cutting along the planned division line.

[0038] Once cutting along all planned division lines aligned in the Y-axis direction is complete, the control unit 16 rotates the holding table 12 by 90 degrees using the rotation support unit 25. As a result, the workpiece 1 on the holding table 12 is positioned so that multiple uncut planned division lines are aligned in the Y-axis direction (extending toward the X-axis direction). Then, cutting is performed sequentially along all the uncut planned division lines in the same manner as described above.

[0039] As described above, by appropriately moving the holding table 12 in the X-axis direction by the moving unit 20 (machining feed), moving the cutting unit 50 in the Y-axis direction by the indexing feed mechanism 30 (indexing feed), moving the cutting unit 50 in the Z-axis direction by the lifting mechanism 40 (depth of cut feed), and rotating the cutting blade 53 in the cutting unit 50, cutting is performed along multiple planned division lines on the surface 2 of the workpiece 1 using the cutting blade 53.

[0040] When the cutting device 10 performs cutting on the workpiece 1, cutting chips are generated. While the cutting device 10 is performing cutting, cutting fluid M is continuously supplied from the shower nozzle 55 and blade cooler 56 to the cutting point K where the cutting blade 53 cuts into the workpiece 1, and to the cutting blade 53 itself. The supplied cutting fluid M washes away the cutting chips from the cutting point K, preventing them from adhering to the surface 2 of the workpiece 1 or the cutting blade 53. The cutting fluid M also serves as cooling water to cool the area around the cutting point K and the cutting blade 53. After washing, the cutting fluid M will be mixed with cutting chips. Hereafter, the cutting fluid containing cutting chips will be referred to as contaminated fluid N.

[0041] Incidentally, during cutting, the cutting fluid M sprayed from the shower nozzle 55 and blade cooler 56 hits the cutting blade 53 which rotates at high speed, making it easy for contaminant fluid N to scatter into the surroundings. If the scattered contaminant fluid N adheres to the surface 2 of the workpiece 1, the chip 3 and other parts will be contaminated with cutting debris. In particular, if the contaminant fluid N dries after adhesion, it becomes difficult to remove the cutting debris from the workpiece 1. For this reason, it is desirable to prevent contaminant fluid N from adhering to the workpiece 1 during cutting, and the cutting apparatus 10 of this embodiment is equipped with a structure that prevents contaminant fluid N from adhering to the workpiece 1. The details are described below.

[0042] As shown in Figures 1 to 3, the cutting device 10 is equipped with a water case 60. The water case 60 is supported on a base 11 and located above the moving unit 20, and has a rectangular frame structure with its longitudinal direction parallel to the X-axis direction. More specifically, the water case 60 has an outer frame and an inner frame. The outer frame is composed of a pair of outer walls 61 extending in the X-axis direction and a pair of outer walls 62 extending in the Y-axis direction. In Figures 1 to 3, one of the outer walls 61 on the near side of the paper is shown in a partially transparent view. The inner frame is composed of a pair of inner walls 63 extending in the X-axis direction and a pair of inner walls 64 extending in the Y-axis direction (see Figure 1). The inside of the inner frame is an opening 601 that penetrates in the Z-axis direction (see Figure 1). A bottom wall 65 is formed at the bottom of the case between the outer frame and the inner frame. The area of ​​the bottom of the water case 60 that runs along the outer wall 61 is a groove 66 that is lower in the Z-axis direction than the bottom wall 65. Drainage holes 661 are formed on the bottom surface of the groove 66.

[0043] A movable plate 67 is supported on the upper part of the inner frame of the water case 60. The movable plate 67 has a horizontal plate portion 671 whose length in the Y-axis direction is greater than the distance between the pair of inner walls 63, and a pair of side plate portions 672 that protrude downward from both edges of the horizontal plate portion in the Y-axis direction, and is shaped to cover the opening 601 of the water case 60 from above. A hole is formed in the movable plate 67 through which the rotation support portion 25 passes in the Z-axis direction, and the movable plate 67 moves in the X-axis direction together with the X-axis movable table 24, the rotation support portion 25, and the holding table 12.

[0044] As shown in Figures 2 and 3, bellows sections 68 and 69 are provided on both sides of the movable plate 67 in the X-axis direction. Note that the bellows sections 68 and 69 are not shown in Figure 1. Each of the bellows sections 68 and 69 has a shape that covers the opening 601 of the water case 60 from above together with the movable plate 67 (a shape with parts corresponding to the horizontal plate section 671 and the side plate section 672), and is expandable and contractible in the X-axis direction. When the movable plate 67 moves forward Xa in the X-axis direction together with the holding table 12, the bellows section 68 contracts and the bellows section 69 extends. When the movable plate 67 moves backward Xb in the X-axis direction together with the holding table 12, the bellows section 69 contracts and the bellows section 68 extends. In this way, even when the holding table 12 moves in the X-axis direction, the state in which the top of the opening 601 is always covered is maintained.

[0045] During cutting, contaminating liquid N scattered around the holding table 12 is prevented from entering downwards through the opening 601 by the moving plate 67, bellows section 68, and bellows section 69, and flows along the moving plate 67, bellows section 68, and bellows section 69 towards the bottom wall 65. The contaminating liquid N that flows towards the bottom wall 65 forms a layer of liquid between the lower ends of the moving plate 67 (side plate section 672), bellows section 68, and bellows section 69 and the bottom wall 65, and the sealing effect of this liquid layer prevents the contaminating liquid N from entering towards the opening 601. In addition, the contaminating liquid N flows into the groove section 66 which is lower than the bottom wall 65, and is discharged to the outside of the water case 60 through the drain hole 661 and the drain pipe 17.

[0046] In this way, the contaminating liquid N scattered around the holding table 12 is collected and discharged to the outside by the water case 60, preventing the contaminating liquid N from adhering to the components of the moving unit 20 located below the holding table 12. However, since the holding table 12 is located above the moving plate 67 and the bellows sections 68 and 69, it is difficult for the water case 60 to prevent the contaminating liquid N from adhering to the workpiece 1 held by the holding table 12. In particular, when the chip 3 (electronic device) formed on the workpiece 1 is a CMOS image sensor or the like, the yield deteriorates depending on the amount of foreign matter adhering at the processing point K, and even if the contaminating liquid N is not yet dry, once foreign matter such as cutting chips contained in the contaminating liquid N adheres to the chip 3, it is difficult to remove with normal cleaning.

[0047] As a countermeasure, the cutting apparatus 10 of this embodiment includes a cover plate 70 that covers the surface 2 of the workpiece 1 to prevent contamination liquid N from adhering to it, and a liquid supply unit 80 that prevents contamination liquid N from entering between the lower surface of the cover plate 70 and the surface 2 of the workpiece 1.

[0048] The cover plate 70 is attached to the water case 60. Figures 1, 2, 5, 6, and 7 show the cover plate 70 attached to the water case 60, while Figure 3 shows the cover plate 70 removed from the water case 60. As shown in Figure 3, a base portion 611 is provided inside a pair of outer walls 61 of the water case 60, and the cover plate 70 is supported so as to span across the base portions 611 on both sides in the Y-axis direction. The cover plate 70 is fixed to the base portions 611 by screws or the like. Note that the structure supporting the cover plate 70 may be provided on a base 11 or the like instead of the water case 60.

[0049] The cover plate 70 is a rectangular plate-shaped member in plan view. The front end Xa in the X-axis direction of the cover plate 70 is designated as the front edge 71, and the rear end Xb in the X-axis direction is designated as the rear edge 72. The ends on both sides of the cover plate 70 in the Y-axis direction are designated as the side edges 73 and side edges 74. The front edge 71 and rear edge 72 are edges that extend in the Y-axis direction, while the side edges 73 and side edges 74 are edges that extend in the X-axis direction.

[0050] The cover plate 70 is made of synthetic resin, metal, or the like. If the liquid supply passage 83, which will be described later, is to be provided inside the cover plate 70, it is easier to manufacture if the cover plate 70 is made of synthetic resin.

[0051] The cover plate 70 is positioned Xb behind the machining point K in the X-axis direction (rearward in the machining feed direction) and is arranged adjacent to the cutting blade 53 in the X-axis direction. More specifically, the front edge 71 of the cover plate 70 is located Xb behind the machining point K in the X-axis direction, and there is a predetermined distance Da between the machining point K and the front edge 71 in the X-axis direction (see Figure 5). The rear edge 72 of the cover plate 70 is located near the outer wall 62 of the water case 60 on the rear Xb side in the X-axis direction (see Figure 2).

[0052] The length of the cover plate 70 in the Y-axis direction is approximately equal to the distance between the pair of base portions 611 provided on the water case 60, and the length of the cover plate 70 from side edge 73 to side edge 74 is greater than or equal to the diameter of the holding surface 13 on the holding table 12 (see Figure 6). Therefore, the cover plate 70 has a length in the Y-axis direction that can cover the entire diameter of the workpiece 1 held on the holding surface 13.

[0053] The cover plate 70 is positioned above the holding surface 13 in the Z-axis direction and is arranged to cover the surface 2 (upper surface) of the workpiece 1 held on the holding surface 13 with a gap. The lower surface of the cover plate 70 is approximately parallel to the holding surface 13. There is a predetermined gap Db in the Z-axis direction between the holding surface 13 and the cover plate 70 (see Figure 6). The gap Db is set as the sum of the Z-axis thickness of the workpiece 1 and tape 4 and the Z-axis gap from the surface 2 of the workpiece 1 to the lower surface of the cover plate 70. As a result, the cover plate 70 can cover the upper surface 2 of the workpiece 1 while maintaining a distance from it without contact.

[0054] The cover plate 70 has an inclined portion 75 in the rear end region in the X-axis direction, including the trailing edge 72. The majority of the cover plate 70, excluding the inclined portion 75, has a horizontal shape extending in the X-axis and Y-axis directions. The inclined portion 75 has an inclined shape that slopes downward in the Z-axis direction as it moves toward the rear Xb (rear in the machining feed direction) in the X-axis direction, and this inclination causes the inclined portion 75 to extend inside the water case 60 (see Figure 7).

[0055] The cutting apparatus 10 further includes a liquid supply unit 80 that supplies liquid between the lower surface of the cover plate 70 and the surface 2 of the workpiece 1. The liquid supply unit 80 has a plurality of liquid supply holes 81 formed in the lower surface of the cover plate 70, a liquid supply tank 82 provided outside the cover plate 70, and a liquid supply passage 83 connecting each liquid supply hole 81 to the liquid supply tank 82. The plurality of liquid supply holes 81 are provided on the cover plate 70 at positions closer to the front Xa in the X-axis direction near the front edge 71, and are arranged at predetermined intervals in the Y-axis direction (see Figures 3, 5, and 6).

[0056] Liquid P is stored in the liquid supply tank 82. When the pump (not shown) is driven, liquid P is sent from the liquid supply tank 82 to the liquid supply passage 83, and liquid P is ejected downward from each liquid supply hole 81 (see Figure 6). The liquid P ejected from each liquid supply hole 81 forms a liquid layer PS (Figure 5) between the lower surface of the cover plate 70 and the surface 2 of the workpiece 1. For example, the liquid P can be pure water or a liquid containing a surfactant in pure water.

[0057] The operation of the cover plate 70 and the liquid supply unit 80 described above will now be explained. When cutting the workpiece 1, the workpiece 1 is fed from the front Xa to the rear Xb in the X-axis direction using the moving unit 20. The cover plate 70 is positioned above the holding surface 13 on the rear Xb side in the X-axis direction from the machining point K. In other words, in the state before cutting the planned division line, a large proportion of the workpiece 1 is exposed and not covered by the cover plate 70, and as the workpiece 1 is fed towards the rear Xb, the proportion of the workpiece 1 that goes under the cover plate 70 increases. The area of ​​the workpiece 1 that has been cut after passing the machining point K goes under the cover plate 70, so the cover plate 70 prevents the contamination liquid N from adhering to the surface 2 and tip 3 of that area.

[0058] When cutting the workpiece 1, the spindle 52 and cutting blade 53 rotate in the R direction as shown in Figures 4 and 5. That is, at the machining point K, the rotating cutting blade 53 generally moves towards the rear Xa in the X-axis direction. Cutting fluid M is sprayed from the shower nozzle 55, located on the front Xa side in the X-axis direction, towards the rear Xb relative to the cutting blade 53 which is rotating in the R direction. The shower nozzle 55 is also configured to spray the cutting fluid M diagonally upward. Therefore, the contaminated fluid N, which is sprayed from the shower nozzle 55 and mixed with cutting chips near the machining point K, is easily scattered towards the rear Xb in the X-axis direction while being bounced diagonally upward as the cutting blade 53 rotates in the R direction (see Figure 5).

[0059] A cover plate 70 is provided at a position on the rear Xb side, behind the cutting blade 53 in the rotational direction from the machining point K, so as to cover the upper part of the surface 2 of the workpiece 1. As shown in Figure 5, the contaminating liquid N, which is propagated towards the rear Xb in the X-axis direction while being bounced diagonally upward, falls onto the upper side of the cover plate 70. The length of the cover plate 70 in the Y-axis direction is greater than the diameter of the holding surface 13 on the holding table 12, and it has a length that covers the entire surface 2 of the workpiece 1 on the holding surface 13 in the Y-axis direction. In addition, the trailing edge 72 of the cover plate 70 extends to the vicinity of the outer wall 62 on the rear Xa side of the water case 60 in the X-axis direction. Therefore, the contaminating liquid N scattered from the machining point K towards the rear Xb in the X-axis direction is prevented from falling downward by the cover plate 70 and does not adhere to the surface 2 of the workpiece 1.

[0060] By positioning the cover plate 70 close to the machining point K in the X-axis direction, the area covered by the cover plate 70 on the workpiece 1 can be increased. Therefore, within a range that does not cause problems, it is preferable to set the distance Da (Figure 5) between the machining point K and the front edge 71 of the cover plate 70 in the X-axis direction to be small. For example, the distance Da is preferably in the range of 35 mm or more and 100 mm or less.

[0061] When the thickness of the cover plate 70 is set to an extremely thin 2 mm, the limit of the distance Da that allows the cover plate 70 to be brought close to the vicinity of the machining point K without interfering with the blade cooler 56 is approximately 35 mm.

[0062] Furthermore, if the thickness of the cover plate 70 is about 10 mm (a thickness that facilitates the formation of a liquid supply passage 83 inside), and the ejection angle of the contaminant liquid N flying diagonally upward from near the machining point K (the angle between the upper surface or holding surface 13 of the workpiece 1 and the lower surface of the cutting fluid M) is about 10°, then the limit value of the spacing Da that prevents the contaminant liquid N from directly contacting the leading edge 71 of the cover plate 70 is about 100 mm. If the contaminant liquid N flying out from near the machining point K collides with the cover plate 70 and scatters, there is a risk that the contaminant liquid N will accumulate around the machining point K and contaminate the workpiece 1. In this case, it is preferable that the spacing Da does not fall below 100 mm.

[0063] The above values ​​for the spacing Da are merely examples, and the spacing Da is adjusted as appropriate, not limited to the above values, depending on conditions such as the scattering angle of the contaminant liquid N from near the machining point K, the thickness of the cover plate 70, and the configuration and shape of the cutting unit 50 including the blade cooler 56.

[0064] The contaminating liquid N that falls onto the upper side of the cover plate 70 flows along the upper surface of the cover plate 70 towards the rear Xb in the X-axis direction and reaches the inclined section 75. As shown in Figure 7, the contaminating liquid N that reaches the inclined section 75 flows diagonally downward along the inclined shape of the inclined section 75 and falls from the rear edge 72 towards the bottom wall 65 and groove 66 of the water case 60. In the region where there is a bellows section 69 below the inclined section 75, the contaminating liquid N that flows down from the inclined section 75 flows along the bellows section 69 and falls onto the bottom wall 65. The contaminating liquid N that falls onto the bottom wall 65 flows into the groove 66 and is discharged to the outside of the water case 60 through the drain hole 661 and drain pipe 17.

[0065] Therefore, the contaminating liquid N that falls onto the upper side of the cover plate 70 can be discharged to the outside of the water case 60 without adhering to the workpiece 1 that gradually moves under the cover plate 70 as the workpiece is fed backward Xb during cutting.

[0066] Furthermore, when cutting the workpiece 1, liquid is supplied by the liquid supply unit 80, and the liquid P ejected downward from the liquid supply hole 81 cleans the surface 2 of the workpiece 1, and a layer of liquid PS (Figure 5) is formed between the lower surface of the cover plate 70 and the surface 2 of the workpiece 1. Since the layer of liquid PS is formed in the area of ​​the surface 2 of the workpiece 1 that goes under the cover plate 70 as the workpiece is fed backward Xb, it is possible to prevent contaminant liquid N from entering between the lower surface of the cover plate 70 and the surface 2 of the workpiece 1. In other words, even on the underside of the cover plate 70, the effect of protecting the workpiece 1 from contamination by contaminant liquid N is obtained.

[0067] The contaminating fluid N is scattered not only on the upper side of the cover plate 70, but in various directions. For example, when the cutting fluid M ejected from the blade cooler 56 hits the side of the rapidly rotating cutting blade 53, a flow of contaminating fluid N is formed that bounces back in directions other than the X-axis. Similarly, the cutting fluid M ejected from the shower nozzle 55 is not always bounced upward diagonally and falls onto the upper side of the cover plate 70; a flow of contaminating fluid N may be formed that travels almost horizontally from the machining point K towards the lower side of the cover plate 70.

[0068] Furthermore, by using the liquid supply unit 80 to form a liquid layer PS between the cover plate 70 and the workpiece 1 on the underside, it is possible to prevent contaminant liquid N scattered in various directions from entering the underside of the cover plate 70 and adhering to the workpiece 1. In addition, the liquid layer PS also prevents contaminant liquid N from adhering to the underside of the cover plate 70, so that not only the workpiece 1 but also the underside of the cover plate 70 facing the surface 2 of the workpiece 1 can be kept clean without any cutting chips adhering to it.

[0069] In particular, since the cover plate 70 has multiple liquid supply holes 81 located towards the front Xa in the X-axis direction, as shown in Figure 5, a liquid layer PS can be formed over a wide area in the X-axis direction, from the front edge 71 of the cover plate 70 to the outer circumference on the rear Xb side of the workpiece 1. Since the liquid layer PS reaches the front edge 71 of the cover plate 70, which is closest to the machining point K where cutting chips are generated, it has a high effect in preventing the intrusion of contaminant liquid N. Furthermore, as shown in Figure 6, since the multiple liquid supply holes 81 are arranged in a line in the Y-axis direction, a liquid layer PS can be formed over the entire diameter of the workpiece 1 in the Y-axis direction. Thus, according to the liquid supply unit 80 of this embodiment, a liquid layer PS can be formed over the entire area of ​​the workpiece 1 that is submerged beneath the cover plate 70, preventing the intrusion of contaminant liquid N.

[0070] Unlike this embodiment, if we were to protect the workpiece 1 from contaminating liquid N by continuously flowing a clean liquid over its surface 2 without providing a cover plate 70, a huge amount of liquid would be required. In contrast, in this embodiment, a thin layer of liquid PS is formed between the cover plate 70 and the workpiece 1, so the amount of liquid P supplied to form the liquid layer PS is far less.

[0071] The gap Db (Figure 6) from the holding surface 13 to the lower surface of the cover plate 70 is set to a value that prevents the cover plate 70 from contacting the workpiece 1 and allows for the proper formation of a liquid layer PS between the cover plate 70 and the workpiece 1. Specifically, it is preferable to set the gap Db to 2 mm or more and 10 mm or less. In particular, in current fully automatic cutting devices, the thickness of the workpiece to be cut (in this embodiment, the combined thickness of the workpiece 1 and the tape 4) is allowed up to about 2 mm, so it is preferable to set the gap Db to about 5 mm to include a margin to ensure that the cover plate 70 is securely separated from the workpiece 1.

[0072] As described above, the cutting apparatus 10 of this embodiment prevents contaminant liquid N, which is cutting fluid containing cutting chips, from adhering to the surface 2 of the workpiece 1 through the action of the cover plate 70 and the liquid supply unit 80. Since the cover plate 70, which has a simple structure, is provided at an appropriate position above the holding surface 13, and liquid P is supplied from the liquid supply hole 81 on the lower surface of the cover plate 70 to form a liquid layer PS, it does not require the supply of a huge amount of liquid to protect the workpiece 1 from contaminant liquid N, nor does it require powerful and large-scale suction equipment to suck up the contaminant liquid N before it adheres to the workpiece 1, thus providing excellent results at low cost.

[0073] Note that there only needs to be one or more liquid supply holes, and the number and arrangement of the liquid supply holes 81 in the above embodiment are not limited. However, it is desirable to have at least one liquid supply hole in a position facing the holding surface 13. This ensures that liquid P is reliably supplied between the lower surface of the cover plate 70 and the surface 2 of the workpiece 1, thereby forming a liquid layer PS.

[0074] Furthermore, the shape of the cover plate is not limited to the cover plate 70 of the above embodiment. For example, the cover plate 70 of the above embodiment is generally a horizontal plate shape, with only the inclined portion 75 being inclined, but it is also possible to make the entire cover plate an inclined shape that slopes downward in the Z-axis direction as it progresses from the front edge (71) in the X-axis direction to the rear edge (72). In this case, the lower surface of the cover plate will be non-parallel to the holding surface 13 of the holding table 12, but as long as the inclination angle of the cover plate with respect to the holding surface 13 is within a predetermined range, a layer of liquid can be formed between the lower surface of the cover plate and the surface 2 of the workpiece 1.

[0075] In the above embodiment, the cover plate 70 has a bent inclined portion 75. However, if the thickness of the cover plate is large, it is also possible to make only the upper surface of the cover plate an inclined surface and form the lower surface of the cover plate as a horizontal surface.

[0076] Furthermore, although the cover plate 70 in the above embodiment has an inclined portion 75 only on the rear edge 72 side, it may also have other inclined portions in the region along the side edges 73 and 74. These other inclined portions can have an inclined shape that slopes downward in the Z-axis direction as it progresses toward the side edges 73 and 74 in the Y-axis direction. This makes it easier to discharge contaminating liquid that has fallen onto the upper side of the cover plate from the side in the Y-axis direction as well.

[0077] Furthermore, although the cover plate 70 in the above embodiment has a flat shape in the area that covers the surface 2 of the workpiece 1, it is also possible to use a curved or unevenly shaped cover plate, as long as the condition that a layer of liquid can be formed between it and the surface 2 of the workpiece 1 is met.

[0078] Furthermore, the embodiments of the present invention are not limited to the embodiments and modifications described above, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Moreover, if the technical idea of ​​the present invention can be realized in a different way by advances in the art or by other derived arts, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention. [Industrial applicability]

[0079] As described above, the cutting apparatus of the present invention can prevent cutting fluid containing cutting chips from adhering to the workpiece at the cutting point where the cutting blade cuts into the workpiece, and is extremely useful in the manufacture of devices such as image sensors, where the adhesion of cutting chips greatly affects the yield. [Explanation of symbols]

[0080] 1: Workpiece 2: Surface (upper surface of the workpiece) 3: Tip 4: Tape 10: Cutting equipment 12: Holding Table 13: Holding surface 16: Control Unit 20: Mobile Unit 24: X-axis movement table 25: Rotating support part 30: Indexing feed mechanism 33: Y-axis moving table 40: Lifting mechanism 44: Z-axis moving table 50: Cutting Unit 51: Spindle Housing 52: Spindle 53: Cutting blade 54: Blade cover 55: Shower nozzle (cutting fluid supply nozzle) 56: Blade cooler (cutting fluid supply nozzle) 57: Cutting fluid tank 58: Cutting fluid supply path 60: Water Case 67: Mobile Plate 68: Bellows 69: Bellows 70: Cover plate 75: Inclined part 80: Liquid supply unit 81:Liquid supply hole 82: Liquid supply tank 83:Liquid supply path 561: Cooler nozzle (cutting fluid supply nozzle) 601: Opening Db: Gap between the retaining surface and the cover plate K: Machining point M: Cutting fluid N: Contamination fluid (cutting fluid containing cutting debris) P:Liquid PS: liquid layer

Claims

1. A holding table having a holding surface for holding a workpiece, A cutting blade rotatably fixed to the tip of the spindle, A cutting fluid supply nozzle that supplies cutting fluid to the cutting point where the cutting blade cuts into the workpiece held on the holding surface, A moving unit that moves the holding table in the processing feed direction, In a cutting apparatus equipped with, A cover plate having a lower surface along the holding surface, with a gap provided to cover the upper surface of the workpiece, and arranged adjacent to the cutting blade at a predetermined interval behind the machining point in the machining feed direction, A cutting apparatus further comprising a liquid supply unit that supplies liquid from one or more liquid supply holes formed on the lower surface of the cover plate to form a layer of liquid between the lower surface of the cover plate and the upper surface of the workpiece.

2. The cover plate is, The cutting device according to claim 1, characterized in that it is installed with a gap of 2 mm or more and 10 mm or less from the holding surface.

3. The cutting apparatus according to claim 1, characterized in that the cover plate has a length equal to or greater than the diameter of the holding surface in the indexing feed direction perpendicular to the machining feed direction.

4. The cutting apparatus according to claim 1, characterized in that the cover plate is formed to slope downward toward the rear in the machining feed direction.

5. The cutting apparatus according to claim 1, characterized in that the liquid supply hole is provided on the cover plate towards the front in the machining feed direction.

Images