Chuck workbench

Abstract

The present invention provides a chuck table that can suppress the consumption of cutting tools and cut the workpiece with high precision even when the workpiece is divided into small chips. The chuck table is mounted on a table base of a cutting device that cuts the workpiece using a cutting tool, and holds the workpiece while the workpiece is cut along a predetermined dividing line and divided into multiple chips. The chuck table includes: a first layer formed of rubber having a dynamic viscoelastic modulus of 0.16 or more and 0.8 or less; and a second layer supported by the first layer and formed of rubber having a static friction coefficient of 1 or more relative to the workpiece, the second layer having: an upper holding surface that contacts the workpiece when holding the workpiece; an opening of a tool relief groove that is provided so as to divide the holding surface corresponding to the predetermined dividing line of the workpiece; and a suction hole provided in an area divided by the opening of the holding surface.

Description

Technical Field

[0001] The present invention relates to a chuck table used when a plate-shaped workpiece is cut with a cutting tool to be divided into a plurality of chips. Background Art

[0002] A package substrate, obtained by sealing multiple semiconductor devices with resin, is cut along predetermined dividing lines, such as streets, to separate the multiple chips containing the semiconductor devices. When a plate-like workpiece, such as a package substrate, is cut and divided into multiple chips, a chuck table designed specifically for the workpiece is sometimes used to hold the workpiece (see, for example, Patent Document 1).

[0003] The chuck table, for example, includes a tool relief groove that allows the cutting tool to avoid interference with the workpiece, and suction holes formed on the surface of the area demarcated by the tool relief groove. This allows the workpiece (multiple chips) to be directly attracted and held after being divided. Specifically, using this chuck table eliminates the need for consumables such as dicing tape affixed to the workpiece to prevent the multiple chips from being dispersed, thus enabling cost-effective division of the workpiece.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-78253

[0005] However, the chuck table retains each chip using the surface area demarcated by the undercut. Therefore, when the chip is small, the contact surface between the chip and the chuck table is smaller than when the chip is large. In other words, the chuck table's force in retaining the chip is weaker when retaining a small chip than when retaining a large chip.

[0006] Therefore, when the workpiece is divided into small chips, the position of the chips may shift or the chips may vibrate, which may reduce the cutting accuracy compared to when the workpiece is divided into large chips. In addition, the vibration of the chips may cause the cutting tool to be significantly worn. Summary of the Invention

[0007] The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a chuck table capable of cutting a workpiece with high precision while suppressing consumption of a cutting tool even when the workpiece is divided into small chips.

[0008] According to one embodiment of the present invention, a chuck worktable is provided, which is installed on a worktable base of a cutting device that uses a cutting tool to cut a workpiece, and holds the workpiece when the workpiece is cut along a predetermined dividing line and divided into multiple chips, wherein the chuck worktable includes: a first layer, which is formed of rubber having a dynamic viscoelastic modulus of not less than 0.16 and not more than 0.8; and a second layer, which is supported by the first layer and is formed of rubber having a static friction coefficient of not less than 1 relative to the workpiece, the second layer having: an upper holding surface, which contacts the workpiece when holding the workpiece; an opening portion of a tool relief groove, which is arranged in a manner to divide the holding surface corresponding to the predetermined dividing line of the workpiece; and a suction hole, which is arranged in the area of ​​the holding surface divided by the opening portion.

[0009] In one embodiment of the present invention, the lower surface of the second layer is in contact with the upper surface of the first layer. Furthermore, in one embodiment of the present invention, the rubber forming the first layer is preferably any of polyurethane rubber, nitrile rubber, ethylene rubber, butyl rubber, fluororubber, silicone rubber, isoprene rubber, butadiene rubber, acrylic rubber, and polysulfide rubber. Furthermore, in one embodiment of the present invention, the rubber forming the second layer is preferably chloroprene rubber.

[0010] A chuck table according to one embodiment of the present invention includes a first layer formed of rubber having a dynamic viscoelastic modulus of 0.16 to 0.8, and a second layer formed of rubber having a static friction coefficient of 1 or greater with respect to a workpiece. The second layer is supported by the first layer, and when holding a workpiece, the workpiece contacts the upper holding surface of the second layer.

[0011] In this way, the first layer that does not contact the workpiece is formed by rubber having a dynamic viscoelastic modulus of greater than 0.16 and less than 0.8, and the second layer that contacts the workpiece is formed by rubber having a static friction coefficient of greater than 1 relative to the workpiece. This allows both a higher vibration-proof effect based on the first layer and a larger friction force based on the second layer to be obtained.

[0012] This reduces chip vibration and chip positional deviation. This means that even when the workpiece is divided into smaller chips, wear of the cutting tool caused by chip vibration and other factors can be reduced. Furthermore, reductions in cutting accuracy caused by chip vibration and chip positional deviation can be suppressed, enabling high-precision cutting of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing a cutting device.

[0014] Figure 2 It is a perspective view showing a workpiece viewed from a predetermined direction.

[0015] Figure 3 Is shown from Figure 2 A perspective view of the workpiece viewed from the opposite direction.

[0016] Figure 4 It is a perspective view showing the table base and the chuck table.

[0017] Figure 5 is a cross-sectional view showing the table base and the chuck table.

[0018] Figure 6 It is a cross-sectional view showing a state in which a workpiece is cut.

[0019] Figure 7 It is a perspective view showing chips obtained by dividing a workpiece.

[0020] Figure 8 This is a side view that magnifies the side of the chip.

[0021] Figure 9 It is a cross-sectional view showing a state in which a workpiece held on a chuck table according to a modified example is cut.

[0022] Description of labels

[0023] 2: Cutting device; 4: Base; 4a: Opening; 6: Worktable moving mechanism; 8: Worktable cover; 10: Corrugated cover; 12: Worktable base; 12a: Upper surface; 12b: Flow path; 12c: Threaded hole; 14: Chuck table; 16: Support structure; 18: Cutting unit moving mechanism; 20: Y-axis guide rail; 22: Y-axis moving plate; 24: Screw shaft; 26: Y-axis pulse motor; 28: Z-axis guide rail; 30: Z-axis moving plate; 32: Screw shaft; 34: Z-axis pulse motor; 3 6: Cutting unit; 38: Cutting tool; 40: Camera (photographing unit); 42: Frame; 42a: 1st surface (upper surface); 42b: 2nd surface (lower surface); 42c: Recess; 42d: Suction hole; 42e: Through hole; 44: 1st layer; 44a: 1st surface (upper surface); 44b: 2nd surface (lower surface); 44c: Suction hole; 46: 2nd layer; 46a: 1st surface (upper surface, holding surface); 46b: 2nd surface (lower surface); 46c: Undercut; 46d: Suction hole ; 48: Screw; 50: Valve; 52: Suction source; 112: Workbench base; 112a: Upper surface; 112b: Flow path; 112c: Threaded hole; 114: Chuck workbench; 142: Support body; 142a: 1st surface (upper surface); 142b: 2nd surface (lower surface); 144: 1st layer; 144a: 1st surface (upper surface); 144b: 2nd surface (lower surface); 144c: Suction hole; 146: 2nd layer; 146a: 1st surface (upper surface, holding surface); 146b : The second surface (lower surface); 146c: The tool back groove; 146d: The suction hole; 148: The fixing frame; 148a: The opening; 148b: The through hole; 150: The screw; 152: The valve; 154: The suction source; 1: The chip (the packaged device chip); 11: The workpiece; 13: The substrate; 13a: The first surface (front); 13b: The second surface (back); 15: The device area; 17: The remaining area; 19: The predetermined dividing line (the interval road); 21: The carrier portion; 23: The resin layer; 25: The electrode. DETAILED DESCRIPTION

[0024] An embodiment of one aspect of the present invention will be described with reference to the drawings. Figure 1 : is a perspective view showing the cutting device 2 of this embodiment. Figure 1 In the figure, some structural elements of the cutting device 2 are omitted. In addition, the X-axis direction (front-back direction, machining feed direction), the Y-axis direction (left-right direction, indexing feed direction), and the Z-axis direction (vertical direction, cutting feed direction) used in the following description are perpendicular to each other.

[0025] like Figure 1As shown, the cutting device 2 includes a base 4 that supports a plurality of structural elements. An opening 4a extending in the X-axis direction is formed on the upper surface of the base 4. A ball screw-type table moving mechanism 6 is disposed within the opening 4a. The table moving mechanism 6 includes an X-axis movable table (not shown) that moves the X-axis movable table along the X-axis direction. Furthermore, the upper portions of the table moving mechanism 6 and the X-axis movable table are covered by a table cover 8 and a bellows cover 10.

[0026] A rectangular parallelepiped worktable base 12, for example, is disposed on the X-axis movable worktable so as to protrude upward from the worktable cover 8. The worktable base 12 is connected to a rotational drive source (not shown), such as a motor, and rotates about a rotation axis generally parallel to the Z-axis. Furthermore, the worktable base 12 is moved in the X-axis direction along with the X-axis movable worktable by the aforementioned worktable moving mechanism 6.

[0027] A chuck table 14 for holding a plate-shaped workpiece 11 is attached to an upper portion of the table base 12 so as to be detachable from the table base 12 as needed. Figure 2 is a perspective view showing the workpiece 11 viewed from a predetermined direction, Figure 3 Is shown from Figure 2 A perspective view of the workpiece 11 viewed from the opposite direction.

[0028] The workpiece 11 is, for example, a package substrate obtained by sealing a plurality of devices with resin. Figure 2 and Figure 3 As shown, the workpiece 11 includes a substrate 13 having a rectangular first surface (front surface) 13a and a rectangular second surface (back surface) 13b located opposite the first surface 13a. The substrate 13 is primarily formed of a metal such as 42 alloy (an alloy of iron and nickel) or copper, and is divided into a plurality of device regions 15 (three device regions 15 in this embodiment) and a remaining region 17 surrounding each device region 15.

[0029] Each device region 15 is further divided into a plurality of regions (16 regions in this embodiment) by a plurality of intersecting dividing lines (streets) 19. A plurality of receiving portions 21 divided by the dividing lines 19 are exposed on the first surface 13a side of the substrate 13. A plurality of metal layers (not shown) are arranged around each receiving portion 21 (in the region overlapping the dividing lines 19) insulated from each other by, for example, resin.

[0030] Components (device chips) such as ICs (Integrated Circuits), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) (not shown) are mounted on the second surface 13b of each mounting portion 21. Electrodes of each component are connected to a metal layer disposed around the mounting portion 21 via metal wires (not shown), and portions of each metal layer serve as electrodes for chips (packaged device chips) obtained by dividing the workpiece 11.

[0031] A resin layer 23 is provided on the second surface 13b side of the substrate 13 to seal the aforementioned devices, metal wires, and the like. The resin layer 23 is formed to a predetermined thickness and protrudes from the second surface 13b of the substrate 13. The entire second surface 13b side of each device region 15 is covered by this resin layer 23. While a package substrate including the substrate 13 is used as the workpiece 11 in this embodiment, the shape, structure, size, and material of the workpiece 11 are not limited.

[0032] like Figure 1 As shown, a gate-shaped support structure 16 is disposed on the upper surface of the base 4 so as to span the opening 4a. A pair of cutting unit moving mechanisms 18 are provided above the front surface of the support structure 16. Each cutting unit moving mechanism 18 has a pair of Y-axis guide rails 20 disposed on the front surface of the support structure 16 and generally parallel to the Y-axis direction. A Y-axis moving plate 22 constituting each cutting unit moving mechanism 18 is mounted on the Y-axis guide rails 20 so as to be slidable along the Y-axis direction.

[0033] A nut (not shown) forming a ball screw is provided on the back (rear) side of each Y-axis moving plate 22. A screw shaft 24, which is substantially parallel to the Y-axis guide rail 20, is rotatably connected to the nut. A Y-axis pulse motor 26 is connected to one end of the screw shaft 24. When the Y-axis pulse motor 26 rotates the screw shaft 24, the Y-axis moving plate 22 moves in the Y-axis direction along the Y-axis guide rail 20.

[0034] A pair of Z-axis guide rails 28 are arranged on the front surface (front face) of the Y-axis moving plate 22, extending substantially parallel to the Z-axis direction. A Z-axis moving plate 30 is mounted on the Z-axis guide rails 28 so as to be slidable along the Z-axis direction. A nut (not shown) constituting a ball screw is provided on the back surface (rear face) of the Z-axis moving plate 30.

[0035] A screw shaft 32 is rotatably coupled to the nut and is substantially parallel to the Z-axis guide rail 28. A Z-axis pulse motor 34 is connected to one end of the screw shaft 32. When the Z-axis pulse motor 34 rotates the screw shaft 32, the Z-axis moving plate 30 moves in the Z-axis direction along the Z-axis guide rail 28.

[0036] A cutting unit 36 ​​for cutting the workpiece 11 is provided below the Z-axis moving plate 30. The cutting unit 36 ​​includes, for example, a cylindrical spindle housing. A spindle having a rotation axis substantially parallel to the Y-axis direction is housed in the space inside the spindle housing.

[0037] A rotational drive source, such as an electric motor, is connected to the base end of the spindle. The front end of the spindle is exposed to the outside from the spindle housing, and a cutting tool 38 is mounted to the front end of the spindle via a tool mount. Cutting tool 38 is formed by fixing abrasive grains, such as diamond, with a bonding material, such as resin, and is annular with a pair of substantially flat side surfaces.

[0038] like Figure 1 As shown, a camera (imaging unit) 40 is fixed to the lower portion of the Z-axis moving plate 30. The camera 40 includes, for example, a two-dimensional optical sensor such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor that is sensitive to visible light, and an imaging lens. The camera 40 is used to capture an image of the workpiece 11 held by the chuck table 14.

[0039] Furthermore, if the Y-axis moving plate 22 of the cutting unit moving mechanism 18 is moved in the Y-axis direction, both the cutting unit 36 ​​and the camera 40 are moved in the Y-axis direction. Furthermore, if the Z-axis moving plate 30 of the cutting unit moving mechanism 18 is moved in the Z-axis direction, both the cutting unit 36 ​​and the camera 40 are moved in the Z-axis direction.

[0040] The top of the base 4 is covered by a cover (not shown). A touch screen (input / output device) (not shown) serving as a user interface is located on the side of the cover. For example, various conditions applied when cutting the workpiece 11 are input to the touch screen. Alternatively, instead of a touch screen with an integrated display (output device) and input device, a display (output device) such as a liquid crystal display and an input device such as a keyboard or mouse may be provided separately.

[0041] The table moving mechanism 6, cutting unit moving mechanism 18, cutting unit 36, camera 40, touch screen and other components are connected to a control unit (not shown). The control unit controls the above components according to a series of steps required for cutting the workpiece 11.

[0042] The control unit is comprised of, for example, a computer including a processing device such as a CPU (Central Processing Unit), a main storage device such as DRAM (Dynamic Random Access Memory), and auxiliary storage devices such as a hard disk drive and flash memory. The functions of the control unit are realized by operating the processing device and other devices according to software stored in the auxiliary storage device. However, the functions of the control unit may also be realized solely through hardware.

[0043] Figure 4 is a perspective view showing the table base 12 and the chuck table 14, Figure 5 1 is a cross-sectional view showing the table base 12 and the chuck table 14. Figure 5 In FIG. 1 , a portion of the structural elements connected to the workbench base 12 is represented by symbols or functional blocks. Figure 4 and Figure 5 As shown, the chuck table 14 includes a flat plate-shaped frame 42 having a rectangular first surface (upper surface) 42a and a rectangular second surface (lower surface) 42b located opposite to the first surface 42a. The frame 42 is formed of metal such as stainless steel.

[0044] The size of the first surface 42a and the size of the second surface 42b of the frame body 42 are larger than the size of the first surface 13a and the size of the second surface 13b of the workpiece 11. In addition, the size of the first surface 42a and the size of the second surface 42b of the frame body 42 are approximately the same as the size of the upper surface 12a of the table base 12 to which the chuck table 14 is mounted. A recessed portion 42c is provided on the first surface 42a side of the frame body 42, and the upper end opening and bottom surface of the recessed portion 42c are rectangular in shape.

[0045] The second surface 44b side of the first layer 44 is fixed to the recess 42c of the frame 42. The first layer 44 has a rectangular first surface (upper surface) 44a and a rectangular second surface (lower surface) 44b located opposite the first surface 44a. The size of the first surface 44a and the size of the second surface 44b of the first layer 44 are slightly smaller than the size of the first surface 13a and the size of the second surface 13b of the workpiece 11, for example.

[0046] However, the size of the first surface 44a and the size of the second surface 44b of the first layer 44 may be the same as the size of the first surface 13a and the size of the second surface 13b of the workpiece 11. In addition, the size of the first surface 44a and the size of the second surface 44b may be larger than the size of the first surface 13a and the size of the second surface 13b.

[0047] The first layer 44 is formed of a soft material that can suppress vibrations of the workpiece 11 during cutting. More specifically, the first layer 44 is made of rubber having a dynamic viscoelastic modulus (loss modulus / storage modulus) of not less than 0.16 and not more than 0.8. This can suppress vibrations of the chips obtained by dividing the workpiece 11, and maintain a high quality of the cutting process. Furthermore, it can suppress wear of the cutting tool 38 caused by, for example, vibrations of the chips.

[0048] Specifically, the first layer 44 can be formed using any one of polyurethane rubber, nitrile rubber, ethylene rubber, butyl rubber, fluororubber, silicone rubber, isoprene rubber, butadiene rubber, acrylic rubber, and polysulfide rubber having a dynamic viscoelastic modulus of 0.16 to 0.8.

[0049] However, as long as the above-mentioned dynamic viscoelastic modulus is satisfied, there is no limitation on the specific material of the first layer 44. On the other hand, in order to obtain a sufficient vibration-proof effect of the first layer 44, it is preferable that the thickness of the first layer 44 (i.e., the distance between the first surface 44a and the second surface 44b) is set to approximately 0.3 mm to 5.0 mm.

[0050] In this embodiment, the dynamic viscoelastic modulus (i.e., loss modulus / storage modulus) value measured using the DMS6100 manufactured by Seiko Instruments Inc. is used. More specifically, the value is measured at a temperature of 20°C and a frequency of 2 Hz for a cylindrical sample having a height of 2 mm and a diameter of 8 mm.

[0051] The second surface 46b side of the second layer 46 is fixed to the first surface 44a of the first layer 44. The second layer 46 has a rectangular first surface (upper surface, holding surface) 46a and a rectangular second surface (lower surface) 46b located opposite the first surface 46a. In other words, the second layer 46 is supported from below by the first layer 44. In this embodiment, the second surface 46b of the second layer 46 is in contact with the first surface 44a of the first layer 44. The size of the first surface 46a and the size of the second surface 46b of the second layer 46 are approximately the same as the size of the first surface 44a and the size of the second surface 44b of the first layer 44.

[0052] The second layer 46 is formed of a material that produces a high static friction force with the workpiece 11 to prevent positional displacement of the workpiece 11 during cutting. More specifically, the second layer 46 is formed of rubber having a static friction coefficient of 1 or greater with respect to the workpiece 11. This prevents positional displacement of the chips obtained by dividing the workpiece 11, thereby maintaining high cutting quality.

[0053] Specifically, the second layer 46 can be formed of chloroprene rubber having a static friction coefficient of 1 or more with respect to the workpiece 11. In addition, in this embodiment, when the workpiece 11 is held by the chuck table 14, the resin layer 23 of the workpiece 11 is brought into contact with the first surface 46a of the second layer 46 (see Figure 6 Therefore, the second layer 46 is preferably formed using chloroprene rubber having a static friction coefficient of 1 or more with respect to the resin layer 23 of the workpiece 11 .

[0054] However, as long as the above-mentioned static friction coefficient is satisfied, there is no limitation on the specific material of the second layer 46. On the other hand, if the second layer 46 is thicker, the vibration-damping effect of the first layer 44 is weakened. Therefore, it is preferable to set the thickness of the second layer 46 (i.e., the distance between the first surface 46a and the second surface 46b) to approximately 0.1 mm to 1.0 mm, for example.

[0055] The second layer 46 is provided with a relief groove 46c for the cutting tool 38 (see FIG. Figure 1 The undercut groove 46c is arranged at a position corresponding to the predetermined dividing line 19 of the workpiece 11, and the first surface 46a of the second layer 46 is divided into a plurality of areas corresponding to the divided workpiece 11 by the opening at the upper end of the undercut groove 46c.

[0056] The width of the relief groove 46c is, for example, wider than the width of the planned dividing line 19 and the cutting tool 38, and the height of the bottom surface of the relief groove 46c is, for example, lower than the height of the lower end of the cutting tool 38 when the cutting tool 38 is inserted into the workpiece 11 to separate the workpiece 11. Therefore, even if the cutting tool 38 is inserted into the workpiece 11, the chuck table 14 and the cutting tool 38 do not interfere with each other.

[0057] In the present embodiment, the undercut 46c is provided so that its bottom surface is located at the same height as the first surface 44a of the first layer 44 (the second surface 46b of the second layer 46). However, the depth of the undercut 46c may be smaller than the thickness of the second layer 46. Similarly, the depth of the undercut 46c may be greater than the thickness of the second layer 46.

[0058] Suction holes 46d are provided in each area of ​​the first surface 46a defined by the opening of the undercut 46c, penetrating the second layer 46 in the thickness direction. Furthermore, suction holes 44c are provided in the first layer 44 at positions corresponding to the suction holes 46d, penetrating the first layer 44 in the thickness direction. Similarly, suction holes 42d are provided in the frame 42 at positions corresponding to the suction holes 46d, penetrating the frame 42 in the thickness direction. The lower end of the suction hole 46d is connected to the upper end of the suction hole 44c, and the lower end of the suction hole 44c is connected to the upper end of the suction hole 42d.

[0059] The upper end (opening) of flow path 12b opens in the central area (the area of ​​chuck table 14 corresponding to recess 42c) on the upper surface 12a of table base 12. Therefore, when chuck table 14 is mounted on upper surface 12a of table base 12, the upper end of flow path 12b is connected to suction hole 42d, suction hole 44c, and suction hole 46d.

[0060] A through-hole 42e is provided at the end of the frame 42 of the chuck table 14, extending through the frame 42 in the thickness direction. Furthermore, a threaded hole 12c is formed in the upper surface 12a of the table base 12 at a position corresponding to the through-hole 42e. Therefore, after the second surface 42b of the frame 42 is brought into contact with the upper surface 12a of the table base 12, the chuck table 14 is secured to the table base 12 by screwing a screw 48 through the through-hole 42e and into the threaded hole 12c.

[0061] The flow path 12b of the table base 12 is connected to a suction source 52 such as a vacuum pump via a valve 50 or the like. Therefore, if the valve 50 is opened while the suction source 52 is in operation, negative pressure generated by the suction source 52 can be applied to the first surface 46a of the chuck table 14 via the flow path 12b, the suction holes 42d, the suction holes 44c, and the suction holes 46d.

[0062] Figure 6 1 is a cross-sectional view showing a state in which the workpiece 11 is cut. Figure 6 In the figure, some components connected to the table base 12 are also shown by symbols or functional blocks. When the workpiece 11 is cut, for example, the resin layer 23 of the workpiece 11 is brought into contact with the first surface 46a of the chuck table 14.

[0063] The position of the workpiece 11 relative to the chuck table 14 is adjusted so that the planned dividing line 19 of the workpiece 11 is located directly above the undercut 46c. Then, the valve 50 is opened while the suction source 52 is in operation. This allows the workpiece 11 to be held against the chuck table 14 by the negative pressure applied through the suction holes 46d.

[0064] Next, the position relationship between the workpiece 11 and the cutting tool 38 is adjusted, as shown in FIG. Figure 6 As shown, the rotating cutting tool 38 is caused to cut into the planned dividing lines 19 of the workpiece 11. By causing the cutting tool 38 to cut into all the planned dividing lines 19 of the workpiece 11, the workpiece 11 is divided into a plurality of chips (package device chips).

[0065] Figure 7 This is a perspective view showing a chip (packaged device chip) 1 obtained by dividing the workpiece 11. When the workpiece 11 is divided along the predetermined dividing line 19, Figure 7 The device shown is a chip 1 sealed with resin. In addition, a plurality of electrodes 25 formed by cutting the metal layer on the planned dividing lines 19 are exposed around the chip 1.

[0066] Figure 8 This is an enlarged side view of the side of chip 1 (including the region of electrode 25). If chip 1 vibrates or shifts position while cutting workpiece 11 using cutting tool 38, the quality of the cutting process can deteriorate. Specifically, for example, the metal forming electrode 25 can be stretched and stretched by cutting tool 38, creating burrs. This can reduce the distance (interval) d between adjacent electrodes 25, potentially leading to problems such as short circuits.

[0067] Therefore, the performance of the chuck table 14 of this embodiment was evaluated based on the distance d between adjacent electrodes 25. Specifically, the workpiece 11 was divided using multiple chuck tables 14 having different dynamic viscoelastic moduli of the rubber constituting the first layer 44. The distance d was then measured for each pair of adjacent electrodes 25 (12 pairs per chip, for a total of 240 pairs) in each of the resulting multiple chips 1 (20 chips each).

[0068] As the dynamic viscoelastic modulus of the rubber constituting the first layer 44, four types were selected: 0.15 (comparative example), 0.16, 0.41, and 0.8. In addition, it is difficult to use a rubber having a dynamic viscoelastic modulus exceeding 0.8 to constitute the first layer 44. Therefore, the upper limit of the dynamic viscoelastic modulus of the rubber constituting the first layer 44 is set to 0.8. As the second layer 46, chloroprene rubber having a static friction coefficient of 1.0 relative to the workpiece 11 is used. In addition, the dynamic viscoelastic modulus of the chloroprene rubber constituting the second layer 46 is approximately 0.1 to 0.15.

[0069] When the workpiece 11 was cut and divided into a plurality of chips 1 using the cutting tool 38, a resin-bonded tool (#240) was used as the cutting tool 38. The rotational speed of the cutting tool 38 was set to 20,000 rpm, and the feed rate of the workpiece 11 was set to 25 mm / s. Furthermore, when any of the chuck tables 14 were used, the positional deviation of the chips 1 relative to the chuck table 14 was not confirmed.

[0070] The measurement results of the distance d are shown in Table 1. Table 1 also shows the average value of the distance d measured for a total of 240 sets of adjacent electrodes 25 .

[0071]

Table 1

[0072] Dynamic viscoelastic modulus Distance d between adjacent electrodes (μm) 0.15 (Comparative Example) 105 0.16 118 0.41 122 0.8 120

[0073] As can be seen from Table 1, when the dynamic viscoelastic modulus of the rubber constituting the first layer 44 is within a range of 0.16 to 0.8, the distance d between adjacent electrodes 25 exceeds the reference value (115 μm), and at least within this range, the processing quality of the workpiece 11 is maintained at a high level. Furthermore, the distance d between adjacent electrodes 25 is maximized when the dynamic viscoelastic modulus is 0.41, which is particularly good.

[0074] As described above, the chuck table 14 of this embodiment includes a first layer 44 formed of rubber having a dynamic viscoelastic modulus of 0.16 or more and 0.8 or less, and a second layer 46 formed of rubber having a static friction coefficient of 1 or more with respect to the workpiece 11. Furthermore, the second layer 46 is supported by the first layer 44, and when holding the workpiece 11, the workpiece 11 contacts the first surface (holding surface) 46a of the upper portion of the second layer 46.

[0075] In this way, the first layer 44 that does not contact the workpiece 11 is formed by rubber having a dynamic viscoelastic modulus of greater than 0.16 and less than 0.8, and the second layer 46 that contacts the workpiece 11 is formed by rubber having a static friction coefficient of greater than 1 relative to the workpiece 11. This allows both a higher vibration-proof effect based on the first layer 44 and a larger friction force based on the second layer 46 to be obtained.

[0076] This can suppress the vibration of the chip 1 and the positional deviation of the chip 1. In other words, even when the workpiece 11 is divided into small chips 1, the wear of the cutting tool 38 caused by the vibration of the chip 1 can be suppressed. In addition, the reduction in cutting accuracy caused by the vibration of the chip 1 and the positional deviation of the chip 1 can be suppressed, so that the workpiece 11 can be cut with high precision.

[0077] In addition, the present invention is not limited to the description of the above-mentioned embodiment, and can be implemented with various modifications. Figure 9 1 is a cross-sectional view showing a state in which the workpiece 11 held on the chuck table 114 of the modified example is cut. Figure 9 In the figure, some structural elements are represented by symbols or functional blocks.

[0078] like Figure 9 As shown, the chuck table 114 of the modified example includes a flat support body 142 having a rectangular first surface (upper surface) 142a and a rectangular second surface (lower surface) 142b located opposite to the first surface 142a. The support body 142 is formed into a porous shape using a resin such as polyurethane, and has a predetermined air permeability.

[0079] The size of the first surface 142a and the second surface 142b of the support body 142 is smaller than the size of the upper surface 112a of the table base 112 to which the chuck table 114 is mounted, and is approximately the same as the upper end (opening) of the flow path 112b that opens in the central area of ​​the upper surface 112a. When the chuck table 114 is mounted on the table base 112, the second surface 142b of the support body 142 is inserted into the upper end of the flow path 112b.

[0080] A second surface 144b of a first layer 144 is fixed to the first surface 142a of the support 142. The first layer 144 has a rectangular first surface (upper surface) 144a and a rectangular second surface (lower surface) 144b located opposite the first surface 144a. The first surface 144a of the first layer 144 is smaller than the first surface 142a and the second surface 142b of the support 142.

[0081] On the other hand, the size of the second surface 144b of the first layer 144 is approximately the same as the size of the first surface 142a and the size of the second surface 142b of the support body 142. In other words, the size of the first layer 144 on the first surface 144a side is smaller than the size on the second surface 144b side. In addition, a step portion is formed on the outer periphery of the first layer 144.

[0082] The first layer 144 is formed of a soft material that can suppress vibrations of the workpiece 11 during cutting. The specific features of the first layer 144 can be the same as those of the first layer 44 of the above-described embodiment. Specifically, the first layer 144 is formed of a rubber having a dynamic viscoelastic modulus of 0.16 or greater and 0.8 or less.

[0083] The second surface 146b of the second layer 146 is fixed to the first surface 144a of the first layer 144. The second layer 146 has a rectangular first surface (upper surface, holding surface) 146a and a rectangular second surface (lower surface) 146b located opposite the first surface 146a. Specifically, the second layer 146 is supported from below by the first layer 144. The second surface 146b of the second layer 146 is in contact with the first surface 144a of the first layer 144. The size of the first surface 146a and the size of the second surface 146b of the second layer 146 are approximately the same as the size of the first surface 144a of the first layer 144.

[0084] The second layer 146 is formed of a material that provides a high static friction force with the workpiece 11 to prevent positional displacement of the workpiece 11 during cutting. The specific features of the second layer 146 can be the same as those of the second layer 46 of the above-described embodiment. Specifically, the second layer 146 is formed of a rubber having a static friction coefficient of 1 or greater with respect to the workpiece 11.

[0085] The second layer 146 is provided with a relief groove 146c into which the lower end of the cutting tool 38 is inserted when cutting the workpiece 11. The relief groove 146c is located at a position corresponding to the planned dividing line 19 of the workpiece 11. The opening at the upper end of the relief groove 146c divides the first surface 146a of the second layer 146 into a plurality of regions corresponding to the divided workpiece 11. The specific features of the relief groove 146c may be the same as those of the relief groove 46c of the above-described embodiment.

[0086] Suction holes 146d are provided in each area of ​​first surface 146a defined by the opening of undercut 146c, penetrating second layer 146 in the thickness direction. Furthermore, suction holes 144c are provided in first layer 144 at positions corresponding to suction holes 146d, penetrating first layer 144 in the thickness direction. The lower ends of suction holes 146d are connected to the upper ends of suction holes 144c, and the lower ends of suction holes 144c are in contact with first surface 142a of support body 142.

[0087] Therefore, when the chuck table 114 is mounted on the table base 112 by inserting the second surface 142b of the support body 142 into the upper end of the flow path 112b, the upper end of the flow path 112b is connected to the suction hole 144c and the suction hole 146d via the support body 142. In addition, when the chuck table 114 is mounted on the table base 112, a fixing frame 148 is used. The fixing frame 148 is made of a metal such as stainless steel and presses the outer periphery of the chuck table 114.

[0088] An opening 148a is provided in the center of the fixing frame 148, extending through the fixing frame 148 in the thickness direction. The opening 148a is configured to allow passage of the portion of the first layer 144 located on the second layer 146 side and the second layer 146, but not the portion of the first layer 144 located on the support body 142 side and the support body 142. Therefore, when the portion of the first layer 144 located on the second layer 146 side and the second layer 146 are inserted into the opening 148a and the fixing frame 148 is secured to the table base 112, the chuck table 114 is also secured to the table base 112.

[0089] A through-hole 148b is provided at the end of the fixing frame 148, extending through the fixing frame 148 in the thickness direction. Furthermore, a threaded hole 112c is formed on the upper surface 112a of the table base 112 at a position corresponding to the through-hole 148b. By inserting a screw 150 through the through-hole 148b and into the threaded hole 112c, the fixing frame 148 is secured to the table base 112. In other words, the chuck table 114 is secured to the table base 112.

[0090] The flow path 112b of the table base 112 is connected to a suction source 154, such as a vacuum pump, via a valve 152 or the like. Therefore, if the valve 152 is opened while the suction source 154 is in operation, negative pressure generated by the suction source 154 can be applied to the first surface 146a of the chuck table 114 via the flow path 112b, the support body 142, the suction holes 144c, and the suction holes 146d.

[0091] The chuck table 114 of this modified example also includes a first layer 144 formed of rubber having a dynamic viscoelastic modulus of 0.16 to 0.8, and a second layer 146 formed of rubber having a static friction coefficient of 1 or greater with respect to the workpiece 11. Furthermore, the second layer 146 is supported by the first layer 144, and when supporting the workpiece 11, the workpiece 11 contacts a first surface (holding surface) 146a on the upper portion of the second layer 146.

[0092] In this way, the first layer 144 that does not contact the workpiece 11 is formed by rubber having a dynamic viscoelastic modulus of greater than 0.16 and less than 0.8, and the second layer 146 that contacts the workpiece 11 is formed by rubber having a static friction coefficient of greater than 1 relative to the workpiece 11. This allows both a higher vibration-proof effect based on the first layer 144 and a larger friction force based on the second layer 146 to be obtained.

[0093] This can suppress the vibration of the chip 1 and the positional deviation of the chip 1. In other words, even when the workpiece 11 is divided into smaller chips 1, the wear of the cutting tool 38 caused by the vibration of the chip 1 can be suppressed. In addition, the reduction in cutting accuracy caused by the vibration of the chip 1 and the positional deviation of the chip 1 can be suppressed, thereby enabling the workpiece 11 to be cut with high precision.

[0094] Furthermore, the chuck table 114 of the modified example has a structure in which the first layer 144 and the second layer 146 are fixed to the support body 142, and is configured to be easily detachable from the table base 112 and the fixing frame 148. Thus, a common fixing frame 148 can be used for a variety of chuck tables 114. Therefore, compared to the case of the chuck table 14 in which the first layer 44 and the second layer 46 are fixed to the frame body 42, the specifications of the chuck table 114 can be changed at a low cost.

[0095] That is, since the chuck table 114 is formed only of a material that is easier to process than metal such as stainless steel, the production cost of the chuck table 114 is reduced. In addition, since the chuck table 114 does not need to be fixed (bonded) to the fixed frame 148, the production cost of the chuck table 114 is also reduced in this regard.

[0096] In the above embodiment, the second surface (lower surface) 46b of the second layer 46 is brought into contact with the first surface (upper surface) 44a of the first layer 44. In the modified example, the second surface (lower surface) 146b of the second layer 146 is brought into contact with the first surface (upper surface) 144a of the first layer 144. However, the chuck table of the present invention is not limited to this embodiment. As long as the vibration isolation effect of the first layer 44 or the first layer 144 can be ensured, another layer may be interposed between the first layer 44 and the second layer 46, or between the first layer 144 and the second layer 146.

[0097] In addition, the structures, methods, and the like of the above-described embodiment and modified examples can be implemented with appropriate changes within the scope not departing from the purpose of the present invention.

Claims

1. A chuck table mounted on a table base of a cutting device that cuts a workpiece using a cutting tool, and holding the workpiece while the workpiece is cut along a predetermined dividing line to be divided into a plurality of chips, characterized in that: The chuck table includes: a first layer formed of rubber having a dynamic viscoelastic modulus of 0.16 or more and 0.8 or less; and The second layer is supported by the first layer and is formed of rubber having a static friction coefficient of 1 or more with respect to the workpiece. This layer 2 has: an upper holding surface that contacts the workpiece when holding the workpiece; The opening of the undercut is provided so as to divide the holding surface corresponding to the planned dividing line of the workpiece; and Suction holes are provided in the area of ​​the holding surface divided by the opening.

2. The chuck table according to claim 1, characterized in that: The lower surface of the second layer contacts the upper surface of the first layer.

3. The chuck table according to claim 1 or 2, characterized in that: The rubber forming the first layer is any of polyurethane rubber, nitrile rubber, ethylene rubber, butyl rubber, fluororubber, silicone rubber, isoprene rubber, butadiene rubber, acrylic rubber, and polysulfide rubber.

4. The chuck table according to any one of claims 1 to 3, characterized in that: The rubber forming the second layer is chloroprene rubber.

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