Method and device for cutting workpiece

Abstract

To reduce an amount of a cutting dust attached to between gaps of a cutting groove when cutting a plurality of workpieces in a state of being held with a chuck table.SOLUTION: The present invention provide a cutting method of each workpiece, for cutting two or more workpieces into which a plurality of division schedule lines crossed each other is provided to each one surface with a cutting blade, comprises: an arrangement step of arranging the two or more workpieces to a holding member in a predetermined interval; a step of holding the holding member into which the two or more workpieces are arranged with a chuck table; and a cutting step of sequentially cutting the two or more workpieces with the cutting blade while supplying a cutting water to the cutting blade in accordance with a cutting order of the two or more workpieces determined so that the workpiece which the cutting groove is already formed is not positioned to a scattering direction where the cutting water supplied to the rotated cutting blade is scattered in accordance with a rotation of the cutting blade.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for cutting workpieces, in which two or more workpieces, each having a plurality of mutually intersecting planned dividing lines set on its surface, are placed on a holding member at a predetermined interval and the two or more workpieces are cut with a cutting blade. [Background technology]

[0002] Package devices are mounted on electronic devices such as mobile phones and personal computers. When manufacturing a package device, first, multiple semiconductor device chips are placed at predetermined positions on a semiconductor package substrate that functions as external connection wiring terminals in the package device.

[0003] The semiconductor device chips are then encapsulated together on the semiconductor package substrate with a sealing resin to form a rectangular strip substrate. A plurality of division lines are set in a grid pattern on one surface of the strip substrate.

[0004] A semiconductor device chip is arranged in each of the rectangular areas partitioned by the multiple streets, and the strip substrate is divided into multiple package devices by cutting the strip substrate along each street using a cutting device.

[0005] The cutting device includes a chuck table having a holding surface for suction-holding a workpiece (e.g., the above-mentioned strip substrate). A cutting unit is disposed above the holding surface. The cutting unit has a cylindrical spindle whose longitudinal direction is disposed substantially parallel to the holding surface, and a cutting blade is attached to the tip of the spindle.

[0006] A cutting water supply nozzle is provided near the cutting blade to supply cutting water such as pure water. During cutting, the cutting water is supplied to the contact point between the workpiece and the cutting blade, cooling the contact point with the cutting water and discharging cutting chips from the contact point while cutting the workpiece.

[0007] Incidentally, in order to improve the efficiency of cutting work, a method has been proposed in which multiple workpieces are integrated with an annular frame via dicing tape and each workpiece is cut (see, for example, Patent Document 1).

[0008] When cutting a workpiece, the chuck table is fed in a predetermined direction while cutting water is supplied. As the cutting blade rotates, cutting water containing cutting chips is scattered in the direction of the velocity vector of the lower end of the cutting blade. For example, when cutting with down-cutting, cutting water is scattered in the same direction as the chuck table's processing feed direction.

[0009] Consider the case where two workpieces are arranged in the feed direction. After cutting the first workpiece located at the leading edge of the feed direction along each street, cutting the second workpiece adjacent to the first workpiece in the opposite direction of the feed direction. This causes cutting water containing cutting chips to splash onto and adhere to the first workpiece. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-196328 Summary of the Invention [Problem to be solved by the invention]

[0011] If cutting water containing cutting chips enters the gaps in the cut groove and the cutting chips adhere to these gaps, it is difficult to completely remove the cutting chips from these gaps even if the workpiece is subjected to spin cleaning after cutting.

[0012] The present invention has been made in consideration of these problems, and aims to reduce the amount of cutting chips that adhere to the gaps in the cutting grooves when cutting multiple workpieces while they are held on a chuck table.

[0013] According to one aspect of the present invention, there is provided a method for cutting two or more workpieces, each having a surface on which a plurality of mutually intersecting planned dividing lines are set, using a cutting blade, the method comprising: an arrangement step of arranging the two or more workpieces on a holding member at a predetermined interval; a holding step of, after the arrangement step, holding the holding member on which the two or more workpieces are arranged by a chuck table; and a cutting step of, after the holding step, sequentially cutting the two or more workpieces with the cutting blade while supplying cutting water to the cutting blade in accordance with a cutting order for the two or more workpieces, the cutting order being determined so that workpieces on which cutting grooves have already been formed are not positioned in a direction in which cutting water supplied to the rotating cutting blade is scattered as the cutting blade rotates, the cutting step including cutting workpieces on which no cutting grooves have been formed being positioned in the direction in which the cutting water is scattered. The number of the two or more workpieces is four to nine, and in the arranging step, the two or more workpieces are arranged on the holding member so as to be spaced apart from each other in a first direction and a second direction perpendicular to the first direction. A method for cutting a workpiece is provided.

[0014] Preferably, each of the two or more workpieces is a rectangular strip substrate, and a device is provided in each of the areas defined by the plurality of planned dividing lines.

[0016] According to another aspect of the present invention, there is provided a workpiece cutting device for cutting two or more workpieces with a cutting blade, each having a surface on which a plurality of mutually intersecting planned dividing lines are set, the device comprising: a chuck table for holding a holding member on which the two or more workpieces are arranged at a predetermined interval; a cutting unit disposed above the chuck table, the cutting unit having a spindle to one end of which the cutting blade is attached; and a control unit having a processor and memory, for controlling the operation of the chuck table and the cutting unit, the control unit having a cutting sequence providing unit that provides a cutting sequence for the two or more workpieces, the cutting sequence being determined so that a workpiece on which a cut groove has already been formed is not positioned in a direction in which the cutting water supplied to the rotating cutting blade is scattered as the cutting blade rotates, and 4 to 9 When cutting the two or more workpieces, the two or more workpieces are arranged on the holding member so as to be spaced apart from each other in a first direction and a second direction perpendicular to the first direction; The operation of the chuck table and the cutting unit controlled by the control unit includes moving the chuck table and the cutting unit relative to one another so as to cut the second workpiece while the first workpiece, which does not have a cutting groove formed therein, is positioned in the direction of splashing of the cutting water, thereby providing a cutting device. [Effects of the Invention]

[0017] In a cutting method according to one aspect of the present invention, two or more workpieces are cut sequentially while supplying cutting water to the cutting blade in a cutting order determined so that workpieces with already formed cutting grooves are not positioned in the direction of cutting water splash caused by the rotation of the cutting blade, thereby reducing the amount of cutting chips adhering to the gaps in the cutting grooves. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. [Figure 2] FIG. 2 is an enlarged perspective view of a part of the cutting unit. [Figure 3] FIG. 3(A) is a diagram showing how the first strip substrate is cut along a first direction, and FIG. 3(B) is a diagram showing how the first strip substrate is cut along a second direction. [Figure 4] Figure 4(A) is a diagram showing how the first strip substrate is cut along a first direction, Figure 4(B) is a diagram showing how the first strip substrate is cut along a second direction, and Figure 4(C) is a diagram showing how the second strip substrate is cut along the first direction. [Figure 5] FIG. 1 is a flow diagram of a cutting method. [Figure 6] FIG. 6(A) is a diagram showing the arrangement step, and FIG. 6(B) is a diagram showing the substrate unit. [Figure 7] FIG. [Figure 8] FIG. 8(A) is a diagram showing one cutting sequence, and FIG. 8(B) is a diagram showing another cutting sequence. [Figure 9] FIG. 10 is a diagram showing a cutting sequence according to a second embodiment. [Figure 10] FIG. 10 is a diagram showing a cutting sequence according to a third embodiment. [Figure 11] FIG. 10 is a diagram showing a cutting sequence according to a fourth embodiment. [Figure 12] FIG. 11 is a top view of a substrate unit according to a fifth embodiment. [Figure 13] FIG. 10 is a diagram showing a cutting sequence according to the fifth embodiment. [Figure 14] FIG. 13 is a top view of a substrate unit according to a sixth embodiment. [Figure 15] FIG. 13 is a diagram showing a cutting sequence according to a sixth embodiment. [Figure 16] FIG. 13 is a top view of a substrate unit according to a seventh embodiment. [Figure 17] FIG. 13 is a diagram showing a cutting sequence according to the seventh embodiment. [Figure 18] FIG. 13 is a top view of a substrate unit according to an eighth embodiment. [Figure 19] FIG. 13 is a diagram showing a cutting sequence according to the eighth embodiment. [Figure 20] FIG. 13 is a top view of a substrate unit according to a ninth embodiment. [Figure 21] FIG. 13 is a diagram showing a cutting sequence according to the ninth embodiment. [Figure 22] FIG. 23 is a top view of the substrate unit of the tenth embodiment. [Figure 23] FIG. 23 is a diagram showing the cutting sequence of the tenth embodiment. [Figure 24] FIG. 23 is a top view of the substrate unit of the eleventh embodiment. [Figure 25] FIG. 23 is a diagram showing the cutting sequence of the eleventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a cutting device 2. In Fig. 1, some of the components of the cutting device 2 are shown in functional blocks. The X-axis direction, Y-axis direction, and Z-axis direction shown in Fig. 1 are perpendicular to one another.

[0020] The +X and -X directions are opposite directions along the X axis, the +Y and -Y directions are opposite directions along the Y axis, and similarly, the +Z and -Z directions are opposite directions along the Z axis.

[0021] The cutting device 2 cuts a plurality of rectangular strip substrates (workpieces) 11. The strip substrates 11 have, for example, long sides of 110 mm, short sides of 60 mm, and a thickness of 1 mm. Each strip substrate 11 has a semiconductor package substrate (not shown) that functions as an external connection wiring terminal in a package device.

[0022] A plurality of rectangular semiconductor device chips 15a (see FIG. 6A), each having a device such as an IC (Integrated Circuit), are arranged in a grid pattern on the semiconductor package substrate. The plurality of semiconductor device chips 15a are collectively sealed on the semiconductor package substrate with resin (for example, molding resin such as epoxy resin containing filler, etc.).

[0023] 6(A) shows the approximate position of the semiconductor device chip 15a, and the semiconductor device chip 15a is not exposed on one surface 11a of the strip substrate 11. Such a strip substrate 11 is also called a package substrate, a sealing resin substrate, etc.

[0024] As shown enlarged in Figure 6(A), on one surface 11a of the strip substrate 11, multiple intended division lines (streets) 13 are set in a grid pattern (intersecting each other) along a first direction 13a1 and a second direction 13a2 that are perpendicular to each other.

[0025] In this specification, the direction of the long sides of the strip substrate 11 is referred to as a first direction 13a1, and the direction of the short sides of the strip substrate 11 is referred to as a second direction 13a2. The above-mentioned semiconductor device chips 15a are arranged in each of the rectangular regions 15 partitioned by the plurality of planned division lines 13.

[0026] One surface 11a of each of the multiple (two or more) strip substrates 11 is exposed, and the other surface 11b of each of the strip substrates 11 is attached to a dicing tape 17. The dicing tape 17 is a circular tape made of resin, and has a laminated structure of a non-adhesive base layer and an adhesive layer that has adhesiveness.

[0027] One surface of a ring-shaped frame 19 made of metal is attached to the outer periphery of the adhesive layer side of the dicing tape 17. The dicing tape 17 and the frame 19 form a holding member 21 for holding a plurality of strip substrates 11.

[0028] The configuration of the holding member 21 is not limited to the dicing tape 17 and the frame 19. The holding member 21 may also have a disk-shaped substrate and an adhesive provided on one surface of the substrate. For example, an ultraviolet-curable resin adhesive is provided on one surface of a disk-shaped transparent glass substrate, and each strip substrate 11 is attached to one surface of the transparent substrate via the adhesive.

[0029] In the first embodiment, four strip substrates 11 are attached in a grid pattern at predetermined intervals 21a, 21b to the center of the adhesive layer side of the dicing tape 17. The interval 21a in the first direction 13a1 and the interval 21b in the second direction 13a2 are each set to, for example, 10 mm or more and 50 mm or less.

[0030] However, the intervals 21a and 21b may be changed as appropriate depending on the size and number of strip substrates 11, the size of the opening in the frame 19, etc. The multiple strip substrates 11 are arranged so that their long sides are approximately parallel to each other and their short sides are approximately parallel to each other.

[0031] Each strip substrate 11 is transported, cut, cleaned, etc. in the form of a substrate unit 23 supported by a frame 19 via a dicing tape 17. A plurality of substrate units 23 are transported to the cutting device 2 while housed in a cassette 4 (see FIG. 1).

[0032] 1, the cutting device 2 will now be described. The cutting device 2 has a rectangular cassette table 6 on which the cassette 4 is placed. Connected to the bottom of the cassette table 6 is an elevator 8 that raises and lowers the cassette table 6 in the Z-axis direction (up and down direction).

[0033] A push-pull arm 10 is provided in the +Y direction of the cassette table 6. The push-pull arm 10 carries the substrate unit 23 out of the cassette 4 or carries the substrate unit 23 into the cassette 4 while gripping the frame 19.

[0034] A pair of guide rails 12 that adjust the position of the substrate unit 23 in the X-axis direction are provided on both sides of the movement path of the push-pull arm 10. A first transport unit 14 that transports the substrate unit 23 between the pair of guide rails 12 is provided near the pair of guide rails 12.

[0035] The first transport unit 14 has an arm, and one end of the arm is provided with a suction mechanism for suctioning the frame 19. The other end of the arm is provided with a rotation mechanism for rotating the arm around a predetermined rotation axis.

[0036] The first transport unit 14 transports the substrate unit 23 to the chuck table 16. The chuck table 16 is movable along the X-axis direction by a ball screw type processing feed unit 18. However, in Fig. 1, the general position of the processing feed unit 18 is shown, and its specific shape and structure are omitted.

[0037] For example, the chuck table 16 moves between a load / unload area A1 near the cassette table 6 and a cutting area A2 located in the -X direction of the load / unload area A1 and where the strip substrate 11 is cut.

[0038] In the cutting region A2, cutting is performed according to predetermined cutting conditions (also called a recipe). During cutting, the chuck table 16 moves back and forth along the X-axis direction in the cutting region A2.

[0039] The chuck table 16 has a disk-shaped metal frame. A recess (not shown) is formed on the upper surface of the frame, and a disk-shaped porous plate is fixed in this recess. Negative pressure is transmitted to the porous plate from a suction source (not shown), such as an ejector, via a gas flow path (not shown) formed in the frame.

[0040] The upper surface of the frame and the upper surface of the porous plate are formed to be substantially flush with each other, and form a holding surface 16a that suction-holds the substrate unit 23 (plurality of strip substrates 11 and holding member 21). The diameter of the holding surface 16a is, for example, approximately 300 mm.

[0041] A plurality of clamp units 16b for clamping the frame 19 are provided on the outer periphery of the chuck table 16. A first drive source (not shown), such as a motor, for rotating the chuck table 16 around a predetermined rotation axis along the Z-axis direction is provided below the chuck table 16.

[0042] Below the first drive source, the above-mentioned processing feed unit 18 that moves the chuck table 16 is disposed. Also, above the chuck table 16, a cutting unit 20 is provided. Here, the cutting unit 20 will be described with reference to FIG. 2.

[0043] 2 is an enlarged perspective view of a portion of the cutting unit 20. The cutting unit 20 has a spindle housing 22 whose longitudinal direction is arranged along the Y-axis direction. A portion of a cylindrical spindle 24 whose longitudinal direction is arranged along the Y-axis direction is rotatably housed in the spindle housing 22.

[0044] One end of the spindle 24 protrudes from the spindle housing 22 in the -Y direction, and a cutting blade 26 having an annular cutting edge is attached to this end. A second drive source (not shown), such as a motor, is provided to the other end of the spindle 24.

[0045] When the second drive source is operated, the cutting blade 26 rotates around the spindle 24 as a rotation axis. The cutting blade 26 of this embodiment rotates in a predetermined direction B. The spindle housing 22 is provided with a blade cover 28 that covers a portion of the cutting blade 26.

[0046] The blade cover 28 has an upper base portion 30 located in the +Z direction of the cutting blade 26. A nozzle block 32 is provided at the end of the upper base portion 30 in the +X direction. The nozzle block 32 has a nozzle 32a provided in a position close to the outer periphery of the cutting blade 26.

[0047] During cutting, the nozzle 32a sprays (supplies) cutting water 34, such as pure water, in approximately the -X direction toward the cutting blade 26. The upper ends of a pair of nozzle units 36 are fixed to the end of the upper base portion 30 in the -X direction.

[0048] Each nozzle unit 36 ​​has a pair of arms 36a arranged along the X-axis direction. The pair of arms 36a are arranged to sandwich the cutting blade 26 in the Y-axis direction. The pair of arms 36a are arranged below the center of rotation of the cutting blade 26 and above the lower end 26a of the cutting blade 26 in the Z-axis direction.

[0049] Each arm 36a has multiple nozzles 36b in an area facing the cutting blade 26. During cutting, each nozzle 36b sprays (supplies) cutting water 34 toward the bottom of the cutting blade 26. However, for convenience, the cutting water 34 sprayed from the nozzles 36b is omitted from Figure 2.

[0050] The cutting water 34 has the function of cooling the contact point between the cutting blade 26 and the strip substrate 11 and the function of discharging cutting chips from the contact point. When the cutting water 34 is sprayed from the nozzles 32a, 36b, the cutting water 34 is scattered in a predetermined direction as the cutting blade 26 rotates.

[0051] Although some of the cutting water 34 is carried around by the rotation of the cutting blade 26 and splashes slightly upward, when viewed in the X-Y plane, the splash direction C of the cutting water 34 is approximately the same as the direction of the velocity vector at the lower end 26a of the cutting blade 26.

[0052] In this embodiment, the strip substrate 11 is cut by down cutting, so the direction of the velocity vector of the lower end portion 26a and the processing feed direction D of the chuck table 16 are the -X direction. Now, returning to Figure 1, other components of the cutting device 2 will be described.

[0053] An imaging unit 38 is provided in the +X direction of the cutting unit 20 so as to face the holding surface 16a. The imaging unit 38 is configured to be movable along the Y-axis direction and the Z-axis direction, and captures an image of, for example, one surface 11a of the strip substrate 11 held by the holding surface 16a.

[0054] The imaging unit 38 has a camera including an objective lens and an imaging element such as a charge-coupled device (CCD) image sensor or a complementary metal-oxide-semiconductor (CMOS) image sensor.

[0055] A ball screw type Z-axis direction moving unit (not shown) that moves the cutting unit 20 along the Z-axis direction is provided in the spindle housing 22. The Z-axis direction moving unit adjusts the cutting depth of the cutting blade 26 in the strip substrate 11 in the Z-axis direction.

[0056] The Z-axis direction moving unit is also provided with a ball screw type Y-axis direction moving unit (not shown) that moves the cutting unit 20 along the Y-axis direction. The Y-axis direction moving unit adjusts the index feed position of the cutting blade 26 in the Y-axis direction relative to the strip substrate 11.

[0057] After the strip substrate 11 is cut by the cutting unit 20, the substrate unit 23 is carried out from the holding surface 16a by the second transport unit 40. A suction mechanism for suctioning the frame 19 is provided at the lower end of the tip of the arm of the second transport unit 40.

[0058] The second transport unit 40 transports the substrate unit 23 to the cleaning device 42. The cleaning device 42 spin-cleans and spin-dries the cut strip substrate 11. The substrate unit 23 that has been cleaned and dried in the cleaning device 42 is loaded into the cassette 4 using the first transport unit 14, the push-pull arm 10, and the pair of guide rails 12.

[0059] A display 44 and input keys 46 are provided on one side of the housing of the cutting device 2. The display 44 displays images captured by the imaging unit 38, cutting conditions, cutting sequence, and the like.

[0060] The input keys 46 are a push-button type user interface for inputting commands from the operator to the cutting device 2. However, a touch panel that functions as both a display device and an input device may be used as the display 44. In this case, the input keys 46 are omitted.

[0061] The elevator 8, the push-pull arm 10, the pair of guide rails 12, the first transport unit 14, the chuck table 16, the first drive source, the cutting unit 20, the imaging unit 38, the second transport unit 40, the cleaning device 42, the display 44, etc. are controlled by the control unit 48.

[0062] The control unit 48 is composed of a computer including, for example, a processor (processing device) 48a represented by a CPU (Central Processing Unit), a main memory device such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), or ROM (Read Only Memory), and an auxiliary memory device such as a flash memory, a hard disk drive, or a solid state drive.

[0063] The memory 48b, which constitutes the auxiliary storage device, stores software including a predetermined program. The functions of the control unit 48 are realized by operating the processor 48a and the like in accordance with this software.

[0064] Furthermore, the memory 48b stores a cutting order providing unit 50 configured as a program. The cutting order providing unit 50 determines the cutting order of the two or more strip substrates 11 according to the arrangement of the two or more strip substrates 11 in the substrate unit 23, and provides the cutting order to the worker via the display 44.

[0065] Specifically, the cutting sequence providing unit 50 determines one or more cutting sequences according to the number and arrangement of the strip substrates 11 in the substrate unit 23, based on a plurality of rules described below. However, the cutting sequence providing unit 50 does not necessarily have to determine a cutting sequence every time cutting is performed.

[0066] Specifically, the cutting sequence providing unit 50 may store cutting sequences prepared in advance according to the number and arrangement of the strip substrates 11, and provide one or more cutting sequences from the stored cutting sequences according to the number and arrangement of the multiple strip substrates 11 in the substrate unit 23.

[0067] Here, a method for determining the cutting order will be described with reference to Figures 3(A) to 4(C). For simplicity, a case will be described in which the substrate unit 23 has four strip substrates 11 (N=4). N is a natural number between 2 and 9, and means the number of strip substrates 11, two or more.

[0068] (Reference orientation of substrate unit 23) Before cutting begins, the substrate unit 23 is positioned, for example, so that the two notches formed in the frame 19 are positioned on the -Y direction side (see FIG. 3(A)). In this embodiment, the orientation of the substrate unit 23 shown in FIG. 3(A) is the reference orientation of the substrate unit 23.

[0069] (Assigning symbols to identify each strip substrate 11) When the substrate unit 23 is in the reference orientation described above, symbols are assigned to the multiple strip substrates 11 on the +Y direction side in order along the X-axis direction so that the -X direction side has a smaller number than the +X direction side.

[0070] In the example shown in Figure 3(A), the strip substrate 11 located at the top left (the -X and +Y direction side of the four) is assigned #1, and the strip substrate 11 located at the top right of Figure 3(A) (the +X and +Y direction side of the four) is assigned #2.

[0071] Next, similar symbols are assigned to one or more strip substrates 11 that are adjacent in the -Y direction to the multiple strip substrates 11 on the +Y side and that form a line in the Y-axis direction. If there are further strip substrates 11, similar symbols are assigned to them.

[0072] In the example shown in Figure 3(A), the strip substrate 11 located at the bottom left (the -X and -Y direction side of the four) is given the number #3, and the strip substrate 11 located at the bottom right (the +X and -Y direction side of the four) is given the number #4.

[0073] Note that each code is set for the convenience of the control unit 48 to identify each strip substrate 11. Therefore, cutting does not necessarily occur in the order of #1 → #2 → #3 → #4. As long as each strip substrate 11 can be identified, symbols or letters may be used instead of codes. Next, the rules to be followed when determining the cutting order will be described.

[0074] (First rule: processing feed direction D) The processing feed direction D in which the chuck table 16 and the cutting unit 20 are relatively processed and fed is determined to be a predetermined direction so that the strip substrate 11 is cut by down-cutting.

[0075] In the example shown in Figures 3(A) and 3(B), the chuck table 16 is moved in the -X direction relative to the cutting unit 20, which is stationary on the X-Y plane, depending on the rotation direction of the cutting blade 26 (predetermined direction B).

[0076] (Second rule: indexing feed direction E) The indexing feed direction E, which indexes and feeds the chuck table 16 and the cutting unit 20 relative to each other, is a predetermined direction perpendicular to the processing feed direction D. In the example shown in Figures 3(A) and 3(B), the indexing feed direction E is the +Y direction.

[0077] (Third rule: Rotation direction of chuck table 16) When changing the cutting direction, the chuck table 16 is rotated 90 degrees in a predetermined direction when viewed from above. Then, when returning the cutting direction to its original state, it is rotated 90 degrees in the opposite direction to this predetermined direction.

[0078] Specifically, when the cutting direction is changed from cutting along the first direction 13a1 shown in Figure 3(A) to cutting along the second direction 13a2 shown in Figure 3(B), the rotation direction of the chuck table 16 is set to 90 degrees clockwise in the top view shown in Figure 3(A).

[0079] Conversely, when returning from cutting along the second direction 13a2 shown in Figure 3(B) to cutting along the first direction 13a1 shown in Figure 3(A), the rotation direction of the chuck table 16 is set to 90 degrees counterclockwise in the top view shown in Figure 3(B).

[0080] (Rule 4: Processing rule) After forming cutting grooves 11c on all of the planned division lines 13 in the first direction 13a1 and all of the planned division lines 13 in the second direction 13a2 on one strip substrate 11, proceed to cutting another strip substrate 11.

[0081] Therefore, in accordance with the fourth rule, each strip substrate 11 is not cut along the first direction 13a1 in the arrangement shown in Figure 3(A) and then cut along the second direction 13a2 in the arrangement shown in Figure 3(B).

[0082] In this embodiment, when cutting the strip substrate 11 according to the first to fourth rules, the cutting order is determined so that the strip substrate 11 on which the cutting groove 11c has already been formed is not positioned in the scattering direction C in which the cutting water 34 is scattered as the cutting blade 26 rotates.

[0083] Specifically, in the substrate unit 23 in the reference orientation shown in Figure 3(A), the cutting order is determined so that no uncut strip substrates 11 are located in the +X and +Y directions of one strip substrate 11 to be cut.

[0084] 3A, the cutting order can be determined in two ways: #2 → #1 → #4 → #3, and #2 → #4 → #1 → #3. Here, the case where the cutting order is #2 → #1 → #4 → #3 will be described.

[0085] FIG. 3(A) is a diagram showing how the strip substrate 11 (#2), which is the first of the four strip substrates 11 to be cut, is cut by the cutting blade 26 along the first direction 13a1.

[0086] Used cutting water 34 containing cutting chips scatters in scattering direction C, but the strip substrate 11 (#1) that is located in scattering direction C starting from the strip substrate 11 (#2) does not have a cutting groove 11c formed therein (i.e., is uncut). Therefore, the used cutting water 34 does not enter the cutting groove 11c, so there is no problem even if the used cutting water 34 adheres to it.

[0087] The four division lines 13 along the first direction 13a1 of the strip substrate 11 (#2) are cut in sequence in the feed direction E to form the cutting grooves 11c (first rule, second rule), and then the substrate unit 23 is rotated +90 degrees clockwise (third rule).

[0088] 3(B) is a diagram showing how the first strip substrate 11 (#2) in the cutting order is cut along the second direction 13a2 by the cutting blade 26. Each planned division line 13 along the second direction 13a2 of the strip substrate 11 (#2) is cut in order in the indexing feed direction E to form cut grooves 11c (first and second rules).

[0089] Even when cutting the strip substrate 11(#2) along the second direction 13a2, the strip substrate 11(#4) located in the scattering direction C starting from the strip substrate 11(#2) remains uncut. Therefore, there is no problem even if the used cutting water 34 adheres to the strip substrate 11(#4).

[0090] After cutting of the strip substrate 11 (#2) is completed, the substrate unit 23 is rotated 90 degrees counterclockwise to return it to the reference orientation shown in Figure 3 (A) (Third Rule), and the next strip substrate 11 (#1) is cut according to the determined cutting order (Fourth Rule).

[0091] First, the four planned division lines 13 along the first direction 13a1 of the strip substrate 11 (#1) are cut in order in the index feed direction E. At this time, since the strip substrate 11 does not exist in the scattering direction C starting from the strip substrate 11 (#1), scattering of the cutting water 34 does not pose a problem.

[0092] Next, each of the division lines 13 along the second direction 13a2 of the strip substrate 11(#1) is cut in order in the indexing feed direction E (see FIG. 3(B)). At this time, the strip substrate 11(#3) located in the scattering direction C starting from the strip substrate 11(#1) is left uncut. Therefore, there is no problem even if the used cutting water 34 adheres to it.

[0093] Similarly, the strip substrate 11 (#4) is cut next, and then the strip substrate 11 (#3) is cut. When cutting is performed in this cutting order, the used cutting water 34 does not splash onto the strip substrate 11 in which the cut grooves 11c have already been formed. The same applies to other cutting orders (#2 → #4 → #1 → #3).

[0094] 4(A) to 4(C) show a comparative example in which used cutting water 34 adheres to the cut strip substrate 11. In the comparative example, the strip substrate 11 is cut in the order of #1 → #2 → #3 → #4.

[0095] In this comparative example, the strip substrate 11 is cut according to the first to fourth rules, but no consideration is given to whether the strip substrate 11, on which the cutting groove 11c has already been formed, is located in the splash direction C of the cutting water 34.

[0096] 4(A) is a diagram showing how the first strip substrate 11(#1) in the cutting order is cut along the first direction 13a1 in the comparative example. When cutting the strip substrate 11(#1), there is no strip substrate 11 in the scattering direction C starting from the strip substrate 11(#1), so scattering of the cutting water 34 is not a problem.

[0097] After cutting the four planned division lines 13 along the first direction 13a1 of the strip substrate 11 (#1) in the indexing feed direction E in sequence, the substrate unit 23 is rotated 90 degrees clockwise, and the four planned division lines 13 along the second direction 13a2 are cut in sequence in the indexing feed direction E.

[0098] 4(B) is a diagram showing how the first strip substrate 11 (#1) in the cutting order in the comparative example is cut by the cutting blade 26 along the second direction 13a2. At this time, the strip substrate 11 (#3) located in the scattering direction C starting from the strip substrate 11 (#1) remains uncut. Therefore, there is no problem even if the used cutting water 34 adheres to the strip substrate 11 (#3).

[0099] After cutting the first strip substrate 11(#1), the substrate unit 23 is returned to the reference orientation (see FIG. 4(C)), and then the strip substrate 11(#2) is cut. FIG. 4(C) is a diagram showing how the second strip substrate 11(#2) in the cutting order in the comparative example is cut along the first direction 13a1.

[0100] However, as shown in Figure 4(C), the strip substrate 11(#1) located in the scattering direction C starting from the strip substrate 11(#2) has already been cut, so used cutting water 34 adheres to the cutting groove 11c of the strip substrate 11(#1).

[0101] In this way, when cutting in accordance with rules 1 to 4, in order to prevent used cutting water 34 from adhering to the cut strip substrate 11, it is necessary to determine the cutting order so that an uncut strip substrate 11 is not positioned in the +X and +Y directions of one strip substrate 11 to be cut in a substrate unit 23 in the reference orientation.

[0102] Next, a cutting method in the first embodiment will be described. Fig. 5 is a flow diagram of the cutting method. First, four strip substrates 11 are arranged on a dicing tape 17 (holding member 21) so as to be spaced apart from each other at predetermined intervals 21a and 21b (arrangement step S10). Fig. 6(A) is a diagram showing the arrangement step S10.

[0103] By attaching each strip substrate 11 to the dicing tape 17, a substrate unit 23 is formed in which four strip substrates 11 are arranged on a holding member 21. FIG. 6(B) is a diagram showing the substrate unit 23.

[0104] After the placement step S10, the cassette 4 containing the substrate unit 23 is placed on the cassette table 6. Thereafter, the worker inputs specific information to the cutting device 2. For example, the worker inputs information about the size of the strip substrate 11 (long side, short side, etc.).

[0105] Furthermore, the operator sets the cutting conditions corresponding to the above-mentioned first to fourth rules in the cutting device 2 using the display 44, input keys 46, etc. Note that if these rules are set automatically, inputting these conditions may be omitted.

[0106] Thereafter, one substrate unit 23 is carried out from the cassette 4 and is suction-held on the chuck table 16 using the holding surface 16a and the plurality of clamp units 16b (holding step S20). Figure 7 is a diagram showing the holding step S20.

[0107] After the holding step S20, each strip substrate 11 of the substrate unit 23 arranged in the reference orientation is imaged by the imaging unit 38. Using the obtained image, position coordinates 11d1, 11d2, 11d3, and 11d4 (see FIG. 3(A)) of the upper left corner (i.e., the -X direction side of the +Y direction) of each strip substrate 11 are obtained.

[0108] The operator inputs the position coordinates corresponding to each strip substrate 11 into the cutting device 2 using the display 44, input keys 46, etc. As a result, the control unit 48 stores the correspondence between one position coordinate and one code (one of #1 to #4).

[0109] It should be noted that if the control unit 48 performs image processing to automatically detect and store the position coordinates 11d1, 11d2, 11d3, and 11d4 from the captured image, the operator may not need to input the position coordinates.

[0110] Then, the control unit 48 determines the cutting order in accordance with the above-mentioned first to fourth rules so that the strip substrate 11 on which the cutting groove 11c has already been formed is not positioned in the scattering direction C in which the cutting water 34 is scattered as the cutting blade 26 rotates, and provides the order to the operator via the display 44 (cutting order providing step S30).

[0111] 8(A) is a diagram showing one cutting sequence 52 (#2 → #1 → #4 → #3), and FIG. 8(B) is a diagram showing another cutting sequence 54 (#2 → #4 → #1 → #3). After the cutting sequence providing step S30, the worker uses the input keys 46 or the like to select one cutting sequence to be actually performed (cutting sequence selecting step S40).

[0112] After the cutting order selection step S40, an alignment step S50 is performed. In the alignment step S50, the imaging unit 38 images the first surface 11a of each strip substrate 11. Specifically, the imaging unit 38 images predetermined markers such as alignment marks provided on the first surface 11a.

[0113] The captured image is then used to align each strip substrate 11. In the alignment, for example, the amount of misalignment between the first direction 13a1 and the X-axis direction around a predetermined rotation axis of the chuck table 16 is detected. The amount of misalignment is stored in a predetermined storage area in the auxiliary storage device of the control unit 48 and is used when cutting each strip substrate 11.

[0114] By aligning all of the strip substrates 11 before cutting the strip substrates 11, the predetermined markings can be captured more clearly than when capturing an image of the surface 11a with cutting debris attached after cutting has started, thereby improving the accuracy of alignment.

[0115] After the alignment step S50, the four strip substrates 11 are cut sequentially according to the determined cutting order (cutting step S60). In the cutting step S60, first, as shown in FIG. 3(A), the alignment result is reflected to make the first direction 13a1 of the strip substrate 11 (#2) approximately parallel to the X-axis direction.

[0116] Then, the lower end of the cutting blade 26, which is rotating at high speed, is positioned at a predetermined cutting depth (for example, the height position between the other surface 11b of the strip substrate 11 and the holding surface 16a), and the cutting blade 26 is positioned on the extension line in the -X direction of one of the planned division lines 13 located at the end in the -Y direction and along the first direction 13a1.

[0117] Then, the first strip substrate 11 (#2) is cut by feeding the chuck table 16 in the processing feed direction D while supplying cutting water 34 to the cutting blade 26. During cutting, the cutting water 34 splashes in the splash direction C, but there is no problem if the used cutting water 34 adheres to the uncut strip substrate 11 (#1).

[0118] After cutting the first strip substrate 11 (#2) along all of the planned division lines 13 parallel to the first direction 13a1, as shown in Figure 3 (B), the first strip substrate 11 (#2) is cut along all of the planned division lines 13 parallel to the second direction 13a2.

[0119] Similarly, the second strip substrate 11 (#1), the third strip substrate 11 (#4), and the fourth strip substrate 11 (#3) are cut in sequence according to the determined cutting order.

[0120] As a result, each strip substrate 11 is cut along the respective intended division lines 13 and divided into a plurality of package devices (not shown). After the cutting step S60, the substrate unit 23 is washed and dried in the washing device 42 and then transported to the cassette 4.

[0121] In this embodiment, the strip substrates 11 are cut in a cutting order determined so that the strip substrates 11 on which the cutting grooves 11c have already been formed are not positioned in the scattering direction C of the cutting water 34, thereby preventing the used cutting water 34 from scattering onto the cut strip substrates 11. This reduces the amount of cutting waste adhering to the gaps in the cutting grooves 11c.

[0122] Next, a second embodiment will be described. In the second embodiment, two strip substrates 11 (N=2) are suction-held on the chuck table 16 via holding members 21 (see FIG. 9). FIG. 9 is a diagram showing a cutting sequence 56 of the second embodiment in a substrate unit 23 in a reference orientation.

[0123] In the cutting order providing step S30 of the second embodiment, the cutting order is determined in the order of #2 → #1 according to the above-mentioned code determination and rules 1 to 4. Note that, also in the second embodiment, each strip substrate 11 is cut according to the procedure shown in FIG.

[0124] Next, a third embodiment will be described. In the third embodiment, three strip substrates 11 (N=3) are suction-held on the chuck table 16 via the holding members 21 (see FIG. 10). FIG. 10 is a diagram showing a cutting sequence 58 in the third embodiment for a substrate unit 23 in a reference orientation.

[0125] In the cutting order providing step S30 of the third embodiment, the cutting order is determined in the order of #3 → #2 → #1 according to the above-mentioned code determination and rules 1 to 4. Note that, also in the third embodiment, each strip substrate 11 is cut according to the procedure shown in FIG.

[0126] Next, a fourth embodiment will be described. In the fourth embodiment, five strip substrates 11 (N=5) are suction-held on the chuck table 16 via holding members 21 (see FIG. 11). In the fourth embodiment, each strip substrate 11 is also cut according to the procedure shown in FIG.

[0127] In the cutting order providing step S30 of the fourth embodiment, the cutting order is also determined in accordance with the above-described code determination and rules 1 to 4. In particular, in the fourth embodiment, when viewed in the second direction 13a2, there are overlapping areas between the strip substrate 11 (#3) and the four strip substrates 11 (#1, #2, #4, and #5) (see FIG. 11).

[0128] Therefore, taking into consideration the overlapping areas of the strip substrates 11 when viewed in the second direction 13a2, the cutting order is determined to be #2 → #1 → #3 → #5 → #4 so that the strip substrates 11 on which the cutting grooves 11c have already been formed are not positioned in the splash direction C of the cutting water 34. Figure 11 is a diagram showing the cutting order 60 of the fourth embodiment for the substrate unit 23 in the reference orientation.

[0129] In addition, the control unit 48 may detect whether or not there is an overlapping area between the strip substrate 11 (#3) and the strip substrates 11 (#1, #2, #4 and #5) when viewed in the second direction 13a2.

[0130] For example, the control unit 48 can detect whether or not an overlapping region exists when viewed in the first direction 13a1 and / or the second direction 13a2 based on an image captured so as to include all of the strip substrates 11.

[0131] Furthermore, the control unit 48 may detect whether or not an overlapping area exists based on information about the size of the strip substrates 11 and the position coordinates of the corners of each strip substrate 11 (such as the above-mentioned position coordinates 11d1).

[0132] If the strip substrates 11 do not overlap each other when viewed in the second direction 13a2, the cutting order is not limited to the above-mentioned #2 → #1 → #3 → #5 → #4. For example, the cutting order may be #2 → #5 → #3 → #1 → #4.

[0133] Next, a fifth embodiment will be described. In the fifth embodiment, six strip substrates 11 (N=6) are suction-held on a chuck table 16 via holding members 21 (see FIG. 12). FIG. 12 is a top view of a substrate unit 23 of the fifth embodiment in the reference orientation.

[0134] In the fifth embodiment, each strip substrate 11 is cut according to the procedure shown in Fig. 5. In the cutting order providing step S30 of the fifth embodiment, the cutting order is also determined according to the above-mentioned code determination and rules 1 to 4. Fig. 13 is a diagram showing a cutting order 62 of the fifth embodiment.

[0135] Next, a sixth embodiment will be described. In the sixth embodiment, seven strip substrates 11 (N=7) are suction-held on the chuck table 16 via holding members 21 (see FIG. 14). FIG. 14 is a top view of a substrate unit 23 of the sixth embodiment in the reference orientation.

[0136] In the sixth embodiment, each strip substrate 11 is cut according to the procedure shown in Fig. 5. In the cutting order providing step S30 of the sixth embodiment, the cutting order is also determined according to the above-mentioned code determination and rules 1 to 4. Fig. 15 is a diagram showing a cutting order 64 of the sixth embodiment.

[0137] Next, a seventh embodiment will be described. In the seventh embodiment, seven strip substrates 11 (N=7) are suction-held on a chuck table 16 via holding members 21 (see FIG. 16). FIG. 16 is a top view of a substrate unit 23 of the seventh embodiment in the reference orientation. The arrangement of the multiple strip substrates 11 in the seventh embodiment differs from that in the sixth embodiment.

[0138] In the seventh embodiment, each strip substrate 11 is cut according to the procedure shown in Fig. 5. Also in the cutting order providing step S30 of the seventh embodiment, the cutting order is determined according to the above-mentioned code determination and rules 1 to 4. Fig. 17 is a diagram showing a cutting order 66 of the seventh embodiment.

[0139] Next, an eighth embodiment will be described. In the eighth embodiment, eight strip substrates 11 (N=8) are suction-held on a chuck table 16 via holding members 21 (see FIG. 18). FIG. 18 is a top view of a substrate unit 23 of the eighth embodiment in the reference orientation.

[0140] In the eighth embodiment, each strip substrate 11 is cut according to the procedure shown in Fig. 5. In the cutting order providing step S30 of the eighth embodiment, the cutting order is also determined according to the above-mentioned code determination and rules 1 to 4. Fig. 19 is a diagram showing a cutting order 68 of the eighth embodiment.

[0141] Next, a ninth embodiment will be described. In the ninth embodiment, eight strip substrates 11 (N=8) are suction-held on the chuck table 16 via holding members 21 (see FIG. 20). FIG. 20 is a top view of a substrate unit 23 of the ninth embodiment in the reference orientation. The arrangement of the multiple strip substrates 11 in the ninth embodiment differs from that in the eighth embodiment.

[0142] In the ninth embodiment, each strip substrate 11 is cut according to the procedure shown in Fig. 5. Also in the cutting order providing step S30 of the ninth embodiment, the cutting order is determined according to the above-mentioned code assignment and rules 1 to 4. Fig. 21 is a diagram showing the cutting order 70 of the ninth embodiment.

[0143] Next, a tenth embodiment will be described. In the tenth embodiment, nine strip substrates 11 (N=9) are suction-held on the chuck table 16 via holding members 21 (see FIG. 22). FIG. 22 is a top view of a substrate unit 23 of the tenth embodiment in the reference orientation.

[0144] In the tenth embodiment, each strip substrate 11 is cut according to the procedure shown in Fig. 5. In the cutting order providing step S30 of the tenth embodiment, the cutting order is also determined according to the first to fourth rules described above. Fig. 23 is a diagram showing a cutting order 72 of the tenth embodiment.

[0145] Next, an eleventh embodiment will be described. In the eleventh embodiment, nine strip substrates 11 (N=9) are suction-held on the chuck table 16 via holding members 21 (see FIG. 24). FIG. 24 is a top view of a substrate unit 23 of the eleventh embodiment in the reference orientation. The arrangement of the multiple strip substrates 11 in the eleventh embodiment differs from that in the tenth embodiment.

[0146] In the eleventh embodiment, each strip substrate 11 is cut according to the procedure shown in Fig. 5. Also in the cutting order providing step S30 of the eleventh embodiment, the cutting order is determined according to the above-mentioned code determination and rules 1 to 4. Fig. 25 is a diagram showing a cutting order 74 of the eleventh embodiment.

[0147] In the second to eleventh embodiments, the used cutting water 34 can be prevented from scattering onto the cut strip substrate 11, thereby reducing the amount of cutting waste adhering to the gaps of the cut grooves 11c. In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention.

[0148] For example, if the above-mentioned reference orientation, code assignment, and rules 1 to 4 are changed, the cutting order is appropriately determined according to the changed state so that the strip substrate 11 on which the cutting groove 11c has already been formed is not positioned in the splash direction C of the cutting water 34.

[0149] In addition, if multiple cutting orders (e.g., three or more) are determined in which the workpiece on which the cutting groove 11c has already been formed is not positioned in the cutting water splash direction C, the control unit 48 may reduce the cutting orders to one or two according to a predetermined standard and then provide them to the worker.

[0150] In the above-described embodiment, a typical arrangement of strip substrates 11 is shown when the number of strip substrates 11 is between two and nine, but the scope of the present invention is not limited to the number and arrangement of strip substrates 11 shown in the figures.

[0151] In addition, in the above-described embodiment, a rectangular plate-shaped strip substrate 11 is cut, but the workpiece may also be two or more circular substrates, semiconductor wafers, or other workpieces each having a diameter smaller than the inner diameter of the frame 19.

[0152] A plurality of mutually orthogonal division lines 13 are set on the surface of the workpiece, similar to the strip substrate 11. In this case, the extension direction of the division lines 13 along one direction is defined as a first direction 13a1.

[0153] The extension direction of the dividing line 13 along another direction perpendicular to the one direction is defined as a second direction 13a2. When cutting this workpiece, the amount of cutting waste adhering to the gaps of the cutting grooves 11c can be reduced by cutting in accordance with the above-mentioned cutting order.

[0154] In the above embodiment, the case where a workpiece such as the strip substrate 11 is cut into individual pieces has been described, but the workpiece does not necessarily have to be cut into individual pieces. For example, the above-described cutting method can also be applied to the case where cut grooves 11c of a predetermined depth that do not completely cut the workpiece are formed along each of the planned dividing lines 13 of the workpiece. [Explanation of symbols]

[0155] 2: Cutting device, 4: Cassette, 6: Cassette table, 8: Elevator 10: push-pull arm, 12: guide rail, 14: first transport unit 11: Strip substrate (workpiece), 11a: One side, 11b: Other side, 11c: Cutting groove 11d1, 11d2, 11d3, 11d4: Position coordinates 13: Planned division line, 13a1: First direction, 13a2: Second direction 15: rectangular area, 15a: semiconductor device chip 16: chuck table, 16a: holding surface, 16b: clamp unit 17: dicing tape, 19: frame, 21: holding member 21a, 21b: spacing, 23: substrate unit 18: Processing feed unit, 20: Cutting unit, 22: Spindle housing 24: spindle, 26: cutting blade, 26a: lower end, 28: blade cover 30: Upper base portion, 32: Nozzle block, 32a: Nozzle 34: cutting water, 36: nozzle unit, 36a: arm, 36b: nozzle 38: Imaging unit, 40: Second transport unit, 42: Cleaning device 44: Display, 46: Input keys 48: control unit, 48a: processor, 48b: memory, 50: cutting order providing unit 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74: Cutting order A1: Loading / unloading area, A2: Cutting area B: Predetermined direction, C: Splash direction, D: Processing feed direction, E: Indexing feed direction

Claims

1. A method for cutting a workpiece by using a cutting blade to cut two or more workpieces, each having a surface on which a plurality of mutually intersecting planned dividing lines are set, a placement step of placing the two or more workpieces on a holding member at a predetermined interval; a holding step of holding the holding member on which the two or more workpieces are placed by a chuck table after the placing step; After the holding step, a cutting step is performed in which the two or more workpieces are sequentially cut with the cutting blade while supplying the cutting water to the cutting blade in accordance with a cutting order of the two or more workpieces, the order being determined so that the workpieces on which cutting grooves have already been formed are not positioned in a direction in which the cutting water supplied to the rotating cutting blade scatters as the cutting blade rotates; Equipped with The cutting step includes cutting a workpiece in a state where the workpiece has no cutting groove formed therein and is positioned in a direction in which the cutting water splashes, The number of the two or more workpieces is between four and nine; A method for cutting a workpiece, characterized in that in the placing step, the two or more workpieces are placed on the holding member so that they are spaced apart from each other in a first direction and a second direction perpendicular to the first direction.

2. The method for cutting a workpiece according to claim 1, characterized in that each of the two or more workpieces is a rectangular plate-shaped strip substrate, and a device is provided in each area partitioned by the plurality of planned division lines.

3. A workpiece cutting device that cuts two or more workpieces, each having a plurality of mutually intersecting planned dividing lines set on one surface, with a cutting blade, a chuck table that holds a holding member on which the two or more workpieces are arranged at a predetermined interval; a cutting unit disposed above the chuck table, the cutting unit having a spindle to which the cutting blade is attached at one end and a nozzle for supplying cutting water to the cutting blade; a control unit having a processor and a memory and controlling the operation of the chuck table and the cutting unit; Equipped with The control unit a cutting order providing unit that provides a cutting order for the two or more workpieces, the order being determined so that the workpieces on which cutting grooves have already been formed are not positioned in a direction in which the cutting water supplied to the rotating cutting blade is scattered as the cutting blade rotates; a cutting device characterized in that, when cutting the two or more workpieces, which number four to nine, according to the cutting order, the two or more workpieces are arranged on the holding member so as to be separated from each other in a first direction and a second direction perpendicular to the first direction, and the operation of the chuck table and the cutting unit controlled by the control unit includes moving the chuck table and the cutting unit relative to each other so as to cut the second workpiece while the first workpiece, which does not have a cutting groove formed therein, is arranged in the direction of splashing of the cutting water.

Images