Method for manufacturing a holding table

Abstract

The present application provides a manufacturing method of a holding table, which can easily manufacture a holding table that effectively performs self-grinding using a grinding device. The manufacturing method of the holding table has the following steps: a first groove forming step of forming a plurality of first grooves on a front surface of a plate-shaped object; a second groove forming step of turning over the plate-shaped object and forming a plurality of second grooves on a back surface of the plate-shaped object; an attraction plate forming step of overlapping a plurality of the plate-shaped objects each having a plurality of the first grooves and a plurality of the second grooves formed therein, and integrating the plurality of the plate-shaped objects to form an attraction plate; and a housing step of housing the attraction plate in a housing recess of a frame having the housing recess formed on an upper surface to form the holding table, wherein the first grooves and the second grooves do not reach side surfaces of the plate-shaped object, a sum of a depth of the first grooves and a depth of the second grooves is greater than a thickness of the plate-shaped object, the first grooves and the second grooves are in communication with each other, and a thickness of the attraction plate is greater than a depth of the housing recess.

Description

TECHNICAL FIELD

[0001] The present application relates to a manufacturing method of a holding table, and a holding table for holding a plate-shaped work in a processing apparatus. BACKGROUND

[0002] In forming a device chip mounted on an electronic device, first, a device such as an IC (Integrated Circuit) or LSI (Large Scale Integration) is formed on the front surface of a semiconductor wafer in a circular plate shape. At this time, a plurality of the devices are arranged in a matrix on the front surface of the semiconductor wafer. Further, the semiconductor wafer is thinned by grinding from the back surface side, and the semiconductor wafer is divided for each device to form the device chip.

[0003] The grinding of the semiconductor wafer is performed by a grinding apparatus (for example, refer to Patent Literature 1). The grinding apparatus has a holding table that attracts and holds a work such as a semiconductor wafer, and a grinding unit that grinds the work attracted and held by the holding table. The grinding unit has a ring-shaped grinding wheel at the lower end. Further, a grinding tool arranged in a circular ring is installed on the lower surface of the grinding wheel facing the upper surface of the holding table.

[0004] The holding table has a porous member whose planar shape is substantially identical to that of the work, and a frame having a receiving recess that receives the porous member in the upper portion. An attraction path whose one end reaches the bottom surface of the receiving recess and whose other end reaches the outside of the frame is provided inside the frame. When the porous member is received in the receiving recess of the frame so that the upper surface of the porous member is exposed, the work is placed on the porous member, and the attraction source is connected to the other end side of the attraction path, a negative pressure is applied to the work via the attraction path and the porous member to attract and hold the work.

[0005] When the work is ground by the grinding apparatus, the grinding wheel is rotated to rotate and move the grinding tool on a ring-shaped track, and the grinding unit is lowered toward the holding table. Then, the bottom surface of the grinding tool contacts the ground surface of the upper surface of the work to grind the work. Here, in order to grind the work with high accuracy, it is necessary to make the upper surface of the porous member of the holding table parallel to the bottom surface of the rotating and moving grinding tool. Therefore, before the work is placed on the porous member, a process called self grind is performed in which the porous member is ground by the grinding tool to adjust the shape.

[0006] However, the types of grinding tools suitable for grinding differ between a workpiece formed of a material such as a semiconductor and a porous member formed of a material such as a ceramic. Therefore, when performing self-grinding, it is necessary to attach a grinding wheel having a dedicated grinding tool to a grinding unit, and it is necessary to replace the grinding wheel with a grinding wheel having a grinding tool suitable for the workpiece after the self-grinding is completed.

[0007] Here, a holding table formed of the same material as the workpiece in a porous structure is known (see, for example, Patent Document 2). In this case, grinding of the holding table and grinding of the workpiece can be performed using the same grinding tool, and therefore replacement of the grinding wheel is not necessary after the self-grinding is performed, and grinding of the workpiece can be started directly after the self-grinding. However, in order to manufacture the holding table having the porous structure, complicated processes are necessary.

[0008] In addition, a technique is known in which an attraction plate formed of the same material as the workpiece is placed on the porous member of the holding table, and the workpiece is held by attraction via the attraction plate and the porous member (see, for example, Patent Document 3). An attraction path is formed inside the attraction plate from one face to the other face. However, in the grinding device, when the self-grinding is performed, the upper surface of the attraction plate is exposed and the negative pressure leaks, and therefore holding of the attraction plate is not easy, and it is difficult to properly perform the self-grinding.

[0009] Patent Document 1: Japanese Patent Application Publication No. 2002-200545

[0010] Patent Document 2: Japanese Patent Application Publication No. 2011-9424

[0011] Patent Document 3: Japanese Patent Application Publication No. 2004-356357

[0012] Therefore, it is also considered to manufacture the holding table by housing the attraction plate in the housing recess of the frame instead of the porous member. However, the attraction plate housed in the housing recess in which the porous member is originally housed needs to have a thickness greater than the depth of the housing recess. Otherwise, when the holding table is self-grounded, the grinding tool comes into contact with the frame first compared to the attraction plate. In this case, it is necessary to replace the grinding wheel for the self-grinding.

[0013] On the other hand, when the attraction plate is simply thickened, it is difficult to form an attraction path from one face to the other face of the attraction plate in the attraction plate. For example, in a case where cut grooves are formed in both faces of the attraction plate using a circular ring-shaped cutting tool so that the cut grooves of both faces communicate at the intersection points of each other, when the attraction plate is thickened, it is necessary to form deeper cut grooves. In order to form deeper cut grooves, a cutting tool having a large blade thickness must be used, and the width of the formed cut grooves also increases. In this case, the workpiece cannot be properly supported using the attraction plate. SUMMARY

[0014] The present application has been achieved in view of this problem, and has an object to provide a manufacturing method of a holding table capable of easily manufacturing a holding table capable of efficiently performing self-grinding by a grinding device.

[0015] According to one embodiment of the present application, there is provided a manufacturing method of a holding table, characterized by comprising: a first groove forming step of forming a plurality of first grooves along a first direction on a front surface of a plate-shaped object; a second groove forming step of turning over the plate-shaped object and forming a plurality of second grooves along a second direction intersecting the first direction on a back surface of the plate-shaped object; a suction plate forming step of overlapping a plurality of the plate-shaped objects each of which is provided with the plurality of first grooves and the plurality of second grooves, and integrating the plurality of plate-shaped objects to form a suction plate; and a housing step of housing the suction plate in a housing recess of a frame body in which the housing recess is formed on an upper surface to form the holding table, the first grooves and the second grooves not reaching side surfaces of the plate-shaped object, a sum of a depth of the first grooves and a depth of the second grooves being greater than a thickness of the plate-shaped object, the first grooves and the second grooves communicating with each other, and a thickness of the suction plate being greater than a depth of the housing recess.

[0016] Preferably, in the first groove forming step, the first grooves are formed by cutting the front surface side of the plate-shaped object using a circular ring-shaped cutting tool, and in the second groove forming step, the second grooves are formed by cutting the back surface side of the plate-shaped object using the cutting tool.

[0017] Alternatively, preferably, in the first groove forming step, the first grooves are formed by ablation machining by irradiating the front surface side of the plate-shaped object with a laser beam of a wavelength absorbed by the plate-shaped object, and in the second groove forming step, the second grooves are formed by ablation machining by irradiating the back surface side of the plate-shaped object with the laser beam.

[0018] Further, preferably, in the housing step, the suction plate is fixed in the housing recess of the frame body by an adhesive material.

[0019] Further, preferably, the manufacturing method of the holding table further comprises an etching step of etching the respective front surface side and back surface side of the plurality of plate-shaped objects before the suction plate forming step.

[0020] Further, preferably, the plate-shaped object and a workpiece held by the holding table are made of the same raw material.

[0021] Further, preferably, one or both of a pitch of the plurality of first grooves and a pitch of the plurality of second grooves is narrower as it is farther from a center of the plate-shaped object.

[0022] In the manufacturing method of the holding table of one embodiment of the present application, a plurality of grooves are formed on the front surface and the back surface of the plate-shaped article in a manner that they cross each other. The plate-shaped articles are overlapped and integrated to form the suction plate. In each plate-shaped article, the grooves of the front surface and the back surface are connected at the crossing points. Therefore, the front surface and the back surface of each plate-shaped article are connected, and the front surface and the back surface of the suction plate are connected. Here, it is easier to form the grooves that communicate with each other on the two surfaces of each plate-shaped article that are thinner than the suction plate.

[0023] Further, by changing the number of plate-shaped articles that constitute the suction plate, the thickness of the suction plate can be adjusted, and thus a suction plate having a thickness exceeding the depth of the housing recess of the frame can be formed. When a holding table is manufactured by forming such a suction plate having a thickness and housing the suction plate in the housing recess, the upper portion of the suction plate is higher than the upper surface of the frame. When the holding table is assembled to a grinding device and self-grinding is performed, the grinding tool can be ground only on the suction plate without contacting the frame.

[0024] Therefore, according to the present application, a manufacturing method of a holding table that can easily manufacture a holding table that can be effectively self-ground by a grinding device is provided. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic perspective view that schematically shows a grinding device.

[0026] Figure 2 is a schematic perspective view that schematically shows a cutting device.

[0027] Figure 3 is a schematic perspective view that schematically shows a first groove forming step.

[0028] Figure 4 (A) of FIG. 1 is a schematic perspective view that schematically shows the front surface side of a plate-shaped article, Figure 4 (B) of FIG. 1 is a schematic perspective view that schematically shows the back surface side of the plate-shaped article.

[0029] Figure 5 (A) of FIG. 2 is a schematic plan view that schematically shows a portion of the front surface side of the plate-shaped article enlarged, Figure 5 (B) of FIG. 2 is a schematic cross-sectional view that schematically shows a portion of the plate-shaped article enlarged.

[0030] Figure 6 (A) of FIG. 3 is a schematic perspective view that schematically shows a case where the plate-shaped articles are stacked, Figure 6 (B) of FIG. 3 is a schematic perspective view that schematically shows a suction plate.

[0031] Figure 7 is a schematic plan view that schematically shows a frame.

[0032] Figure 8(A) is a cross-sectional view schematically showing a housing step, Figure 8 (B) is a cross-sectional view schematically showing a manufactured holding stage.

[0033] Figure 9 is a plan view schematically showing a modification example of the frame body.

[0034] Figure 10 (A) is a cross-sectional view schematically showing a housing step, Figure 10 (B) is a cross-sectional view schematically showing a manufactured holding stage.

[0035] Figure 11 is a perspective view schematically showing a laser processing device.

[0036] Figure 12 is a flowchart showing a flow of each step of a manufacturing method of a holding stage.

[0037] Explanation of Reference Numerals

[0038] 1: plate-shaped article; la, 19a: front surface; lb, 19b: back surface; lc: side surface; 3: first groove; 5: second groove; 7: ring-shaped frame; 9: adhesive tape; 11: frame unit; 13: first direction; 15: second direction; 17: communication path; 19: suction plate; 2: grinding device; 4, 46, 102: base; 4a, 46a: opening; 6, 48, 108, 118: moving table; 8, 50: dust and drip-proof cover; 10, 10a, 52, 126: holding stage; 12, 12a: frame body; 14: suction plate; 16: carry-out and carry-in region; 18: processing region; 20, 132: support portion; 22, 66: lifting unit; 24, 60, 68, 106, 116: guide rail; 26, 62, 70: moving plate; 28, 64, 72, 110, 120: ball screw; 30, 74, 112, 122: pulse motor; 32: grinding unit; 34: spindle housing; 36: spindle; 38: grinding wheel mounting seat; 40: grinding wheel; 42: grinding tool; 44: cutting device; 52a, 128: porous member; 52b, 130: jig; 54: support structure; 56: arm portion; 58: indexing feed unit; 76: cutting unit; 76a: tool cover; 76b: imaging unit; 78: cutting tool; 78a: base; 78b: cutting edge; 80: spindle housing; 82: nozzle; 86: housing recess; 88: through-hole; 90: suction groove; 90a: radial groove; 90b: annular groove; 92: suction path; 94: flat surface; 96: adhesive material; 98: plate suction path; 100: laser processing device; 104, 114: moving unit; 124: cover; 134: laser beam irradiation unit. DETAILED DESCRIPTION

[0039] An embodiment of the present application will be described with reference to the drawings. In the manufacturing method of the holding table of the present embodiment, a holding table that can be used in holding a workpiece by a machining device is manufactured. In particular, the holding table can be appropriately used for a grinding device that grinds a workpiece. However, the use of the holding table is not limited to this, and the holding table can be used for other purposes.

[0040] First, a grinding device that uses the holding table manufactured using the manufacturing method of the holding table of the present embodiment will be described. Figure 1 is a perspective view schematically showing a grinding device 2. An opening 4a is formed on an upper surface of a base 4 that supports each component of the grinding device 2. A moving table 6 on which the holding table 10 is placed on the upper surface is provided in the opening 4a. The moving table 6 moves between a carry-in / carry-out area 16 in which a workpiece is loaded onto or unloaded from the holding table 10 and a machining area 18 in which grinding of the workpiece is performed.

[0041] Both end portions of the moving table 6 in a moving direction of the moving table 6 that moves between the carry-in / carry-out area 16 and the machining area 18 are connected with a crumpled dust and drip prevention cover 8 that stretches and contracts in accordance with the movement of the moving table 6 in a manner of covering the opening 4a. A moving mechanism that is not shown and that moves the moving table 6 in the moving direction is provided below the dust and drip prevention cover 8.

[0042] The holding table 10 placed on the moving table 6 has an attraction plate 14 whose diameter corresponds to the diameter of the workpiece and a frame 12 in which a receiving recess that receives the attraction plate 14 is formed on the upper surface. The upper surface of the holding table 10 serves as a holding surface that holds the workpiece. The holding table 10 has an attraction path (not shown in Figure 1 ) that is connected at one end to the attraction plate 14 and at the other end to an attraction source that is not shown in the inside.

[0043] When the workpiece is held by the holding table 10, the workpiece is placed on the holding surface. Then, when the attraction source is activated, the workpiece placed on the holding surface is subjected to negative pressure, and the workpiece is attracted and held on the holding table 10.

[0044] The upper end of a rotation shaft (not shown) in a direction perpendicular to the holding surface is installed at the center of the bottom of the holding table 10. The lower end of the rotation shaft is connected to a rotation drive source that is not shown. When the rotation drive source is activated, the holding table 10 rotates around the rotation shaft that is perpendicular to the holding surface.

[0045] A grinding unit 32 that grinds a workpiece is disposed above the processing area 18. A support portion 20 is vertically provided at a rear end of the base 4 of the grinding device 2, and the grinding unit 32 is supported by the support portion 20. A lifting unit 22 that lifts the grinding unit 32 is disposed on a front surface of the support portion 20. The lifting unit 22 has a pair of guide rails 24 that are disposed on the front surface of the support portion 20 and extend in the vertical direction, and a moving plate 26 that is slidably attached to the guide rails 24.

[0046] A nut portion (not shown) in which a ball screw 28 parallel to the guide rails 24 is screwed is provided on the back side (rear surface side) of the moving plate 26. A pulse motor 30 is connected to one end of the ball screw 28. If the ball screw 28 is rotated by the pulse motor 30, the moving plate 26 moves in the vertical direction along the guide rails 24.

[0047] The lifting unit 22 includes the guide rails 24, the moving plate 26, the ball screw 28, and the pulse motor 30. The grinding unit 32 is fixed to the front surface of the moving plate 26. When the lifting unit 22 is operated, the grinding unit 32 fixed to the moving plate 26 can be lifted.

[0048] The grinding unit 32 has a spindle 36 that extends in the vertical direction, a spindle housing 34 that covers an upper portion of the spindle 36, and a motor (not shown) connected to a base end side (upper end side) of the spindle 36. In addition, a grinding wheel mount 38 is disposed on a front end side (lower end side) of the spindle 36, and a grinding wheel 40 is fixed to a lower surface of the grinding wheel mount 38.

[0049] A plurality of grinding stones 42 arranged in a circular ring are attached to the lower surface of the grinding wheel 40. The grinding stones 42 have, for example, a bond material formed of resin or the like, and abrasive grains such as diamonds dispersed and fixed in the bond material. When the spindle 36 is rotated by operating the motor, the grinding stones 42 move on the circular ring track. When the grinding unit 32 is lowered in the state in which the spindle 36 is rotated, the grinding stones 42 come into contact with the upper surface of the workpiece held by the holding table 10, and the workpiece is ground and thinned.

[0050] In the grinding device 2, in order to grind the workpiece with high accuracy, it is necessary to make the holding surface of the holding table 10 parallel to the bottom surface of the grinding stones 42 that rotate and move. Therefore, after the workpiece is placed on the holding table 10, a process called self-grinding is performed in which the holding surface of the holding table 10 is ground by the grinding stones 42 to adjust the shape. Here, when the suction plate 14 of the holding table 10 is formed of the same material as the workpiece, the self-grinding and the grinding of the workpiece can be performed by the same grinding stones 42.

[0051] The workpiece subjected to grinding by the grinding device 2 is, for example, a substantially circular plate-shaped substrate formed of a material such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), GaAs (gallium arsenide), or another semiconductor. Alternatively, the workpiece is a substrate formed of a material such as sapphire, glass, quartz, or the like.

[0052] A plurality of devices such as ICs, LSIs, or the like are arranged in a matrix on the front surface of the workpiece. When the workpiece is thinned by grinding from the back surface side and then separated for each device, individual device chips are obtained. The device chips are mounted on electronic equipment such as mobile phones or personal computers and used.

[0053] In addition, the attraction plate 14 that holds the worktable 10 does not need to be formed of the same raw material as the workpiece. As long as the raw material is the same degree of difficulty in grinding as the grinding tool 42 based on the workpiece, the grinding wheel 40 does not need to be replaced before and after grinding. Therefore, the raw material of the attraction plate 14 is not limited to the raw material of the workpiece.

[0054] Next, the cutting device used in the manufacturing method of the holding worktable of the present embodiment will be described. Figure 2 is a perspective view schematically showing the cutting device 44. The cutting device 44 has a base 46 that supports each constituent element.

[0055] A rectangular opening 46a is formed on the upper surface of the base 46 in the length direction along the X-axis direction (machining feed direction). A dust and drip-proof cover 50 in a crumpled shape that is stretched and contracted in accordance with the movement of a moving table 48 is connected within the opening 46a. A moving mechanism (machining feed unit) not shown that moves the moving table 48 in the X-axis direction is provided below the dust and drip-proof cover 50.

[0056] A holding worktable 52 is provided on the upper surface of the moving table 48. The holding worktable 52 has a function of attracting and holding a workpiece placed on a porous member 52a exposed upward. The upper surface of the porous member 52a serves as a holding surface that holds the workpiece. The holding worktable 52 has a plurality of jigs 52b around the holding surface. As described later using Figure 3 the jig 52b has a function of holding the annular frame 7 that constitutes the frame unit 11 including the plate-shaped object 1 as the workpiece.

[0057] An attraction path (not shown) connected to an attraction source (not shown) such as an ejector provided outside the holding table 52 is formed inside the holding table 52. The other end of the attraction path reaches the porous member 52a. When the workpiece is placed on the holding surface and the attraction source is operated, the holding table 52 can hold the workpiece by attraction. The holding table 52 is connected to a rotational drive source (not shown) such as a motor and rotates around a rotational axis substantially parallel to the Z-axis direction (vertical direction).

[0058] A cutting unit 76 is provided above the holding table 52. A support structure 54 for supporting the cutting unit 76 is disposed on the upper surface of the base 46. The support structure 54 has an arm portion 56 extending above the opening 46a in a manner so as to cross the opening 46a.

[0059] A dividing feed unit 58 for moving the cutting unit 76 in the Y-axis direction (dividing feed direction) is provided on the upper portion of the front surface of the support structure 54. The dividing feed unit 58 has a pair of Y-axis guides 60 extending in the Y-axis direction on the front surface of the support structure 54. A Y-axis moving plate 62 is slidably mounted on the pair of Y-axis guides 60. A nut portion (not shown) in which a Y-axis ball screw 64 parallel to the Y-axis guides 60 is screwed is provided on the back surface side (rear surface side) of the Y-axis moving plate 62.

[0060] A Y-axis pulse motor (not shown) is connected to one end portion of the Y-axis ball screw 64. The Y-axis ball screw 64 is rotated by the Y-axis pulse motor, whereby the Y-axis moving plate 62 moves in the Y-axis direction along the Y-axis guides 60.

[0061] A lifting unit 66 for lifting the cutting unit 76 in the Z-axis direction (vertical direction) is provided on the front surface (front surface) of the Y-axis moving plate 62. The lifting unit 66 has a pair of Z-axis guides 68 in the Z-axis direction on the front surface of the Y-axis moving plate 62. A Z-axis moving plate 70 is slidably mounted on the pair of Z-axis guides 68.

[0062] A nut portion (not shown) in which a Z-axis ball screw 72 is screwed in a manner so as to be provided in a direction parallel to the Z-axis guides 68 is provided on the back surface side (rear surface side) of the Z-axis moving plate 70. A Z-axis pulse motor 74 is connected to one end portion of the Z-axis ball screw 72, and the Z-axis ball screw 72 is rotated by the Z-axis pulse motor 74, whereby the Z-axis moving plate 70 moves in the Z-axis direction along the Z-axis guides 68.

[0063] A cutting unit 76 is fixed to a lower portion of the Z-axis moving plate 70. A photographing unit 76b for photographing a workpiece held by the holding stage 52 to detect a machining position is provided adjacent to the cutting unit 76. The positions of the cutting unit 76 and the photographing unit 76b in the Y-axis direction are controlled by the indexing feed unit 58, and the positions of the cutting unit 76 and the photographing unit 76b in the Z-axis direction are controlled by the lifting unit 66.

[0064] In Figure 3 a perspective view schematically showing the cutting unit 76 is included. The cutting unit 76 has a cylindrical spindle housing 80 that houses a spindle having a cutting tool 78 attached to a front end thereof. A spindle as a rotation shaft substantially parallel to the Y-axis direction is rotatably housed in the spindle housing 80.

[0065] The cutting tool 78 has a ring-shaped base 78a formed of aluminum or the like and a ring-shaped cutting edge 78b fixed to an outer peripheral portion of the base 78a. The cutting edge 78b is formed by, for example, fixing abrasive grains such as diamonds with a bonding material such as resin or metal.

[0066] A rotation drive source (not shown) such as a motor is connected to the other end side of the spindle, and the cutting tool 78 is rotated when the spindle is rotated by the rotation drive source. A tool cover 76a that covers an upper side of an outer peripheral portion of the cutting tool 78 is provided on the one end side of the spindle housing 80.

[0067] A pair of nozzles 82 configured to sandwich the cutting tool 78 in the Y-axis direction is provided on the lower end of the tool cover 76a. Cutting water is supplied to the cutting tool 78 or the workpiece from the pair of nozzles 82 when the workpiece is cut. As the cutting water, for example, water (pure water) or a liquid in which a medicine is added to water is used.

[0068] Next, a manufacturing method of the holding stage of the present embodiment will be described. In the manufacturing method, plate-shaped objects that are the same in shape and raw material as the workpiece machined by the grinding device 2 are prepared, and the plate-shaped objects are machined to form suction passages that communicate two faces. Further, the plate-shaped objects in which the suction passages are formed are integrated to form the suction plate 14, and the suction plate 14 is housed in the housing recess of the frame 12 to manufacture the holding stage. Figure 12 is a flowchart showing a flow of each step of the manufacturing method of the holding stage of the present embodiment.

[0069] Here, the plate-shaped object that is a component of the suction plate 14 will be described. In Figure 3A perspective view schematically showing the plate-like object 1 is included. The plate-like object 1 can also be a silicon wafer, for example, in a case where grinding of a silicon wafer as a workpiece is scheduled to be performed by the grinding device 2. The first groove forming step S10 and the second groove forming step S20 described later are performed by the cutting device 44.

[0070] As shown in Figure 3 , the plate-like object 1, the adhesive tape 9, and the annular frame 7 can be integrated to form the frame unit 11 before the plate-like object 1 is carried into the cutting device 44. That is, the adhesive tape 9 is attached to the annular frame 7 in a manner to close the opening of the annular frame 7, and the plate-like object 1 is attached to the adhesive surface of the adhesive tape 9 exposed in the opening. The plate-like object 1 is attached to the adhesive tape 9 with the back surface lb side of the plate-like object 1 facing downward, for example, so that the front surface la side of the plate-like object 1 is exposed upward.

[0071] Also, after the frame unit 11 is formed, the plate-like object 1 in the state of the frame unit 11 is carried into the cutting device 44, and the plate-like object 1 in the state is processed by the cutting device 44. However, the plate-like object 1 can not necessarily be integrated with the adhesive tape 9 and the annular frame 7.

[0072] In the manufacturing method of the holding table of the present embodiment, first, the first groove forming step S10 is performed. The first groove forming step S10 is performed by the cutting device 44 shown in Figure 2 , for example. First, the frame unit 11 including the plate-like object 1 is placed on the porous member 52a of the holding table 52, the annular frame 7 is gripped by the jig 52b, and the plate-like object 1 is suction-held through the adhesive tape 9. Also, the holding table 52 is rotated so that the processing feed direction (X-axis direction) of the cutting device 44 coincides with the orientation of the first direction 13 of the plate-like object 1 (refer to Figure 4 ).

[0073] Figure 3 is a perspective view schematically showing the first groove forming step S10. In Figure 3 , the holding table 52 and the like are omitted. As shown in Figure 3 , in the first groove forming step S10, a plurality of first grooves 3 along one direction are formed on the front surface la of the plate-like object 1. Here, as shown in Figure 3 , the two ends of each of the first grooves 3 formed on the front surface la side of the plate-like object 1 by the first groove forming step S10 do not reach the side surface lc of the plate-like object 1.

[0074] When the first groove 3 is formed in the plate-like object 1, first, the cutting edge 78b of the cutting tool 78 of the cutting unit 76 is positioned above one end of the formation predetermined line of the first groove 3 to be formed first. And, the cutting tool 78 is rotated at a rotation speed of about 30,000 rpm, and the cutting unit 76 is lowered, so that the cutting tool 78 is cut into the front face la of the plate-like object 1.

[0075] Then, the front face la side of the plate-like object 1 is cut by the cutting tool 78 in a manner that the plate-like object 1 is processed to reach the other end of the formation predetermined line of the first groove 3. And, when the cutting tool 78 reaches the other end of the formation predetermined line of the first groove 3, the processing feed of the plate-like object 1 is stopped, and the cutting unit 76 is raised. Thus, the first groove 3 is formed in the front face la of the plate-like object 1.

[0076] Then, the cutting unit 76 is moved above one end of the formation predetermined line of the next first groove 3 to be formed, and the next first groove 3 is formed in the front face la of the plate-like object 1 in the same manner. The above process is repeated, and as shown in (A) of FIG. 1, a plurality of first grooves 3 along the first direction 13 are formed in the front face la of the plate-like object 1. Figure 4

[0077] Here, the depth of the first groove 3 formed by the first groove formation step S10 can be set so that the depth of the first groove 3 and the depth of the second groove 5 formed in the back face lb side of the plate-like object 1 by the second groove formation step S20 to be described later exceed the thickness of the plate-like object 1. More preferably, the depth of the first groove 3 and the depth of the second groove 5 each exceed half of the thickness of the plate-like object 1. In the first groove formation step S10 and the second groove formation step S20, the lowering position of the cutting unit 76 is controlled in a manner that the first groove 3 and the second groove 5 formed become a predetermined depth.

[0078] Next, the second groove formation step S20 will be described. The second groove formation step S20 is implemented by the cutting device 44 in the same manner as the first groove formation step S10. Figure 4 (B) of FIG. 1 is a perspective view schematically showing the plate-like object 1 in which a plurality of second grooves 5 along the second direction 15 are formed in the back face lb side by the second groove formation step S20. In the second groove formation step S20, the plate-like object 1 is flipped over, and a plurality of second grooves 5 along the second direction 15 intersecting the first direction 13 are formed in the back face lb of the plate-like object 1.

[0079] ​Here, in the case where the plate-shaped object 1 is assembled to the frame unit 11 at the time of implementing the first groove forming step S10, the replacement of the adhesive tape 9 needs to be performed at the time of implementing the second groove forming step S20. That is, a new adhesive tape 9 is attached to the front face la side of the plate-shaped object 1, and the old adhesive tape 9 attached to the back face lb side is peeled off to expose the back face lb side of the plate-shaped object 1. Then, the newly formed frame unit 11 is placed on the holding table 52, and the plate-shaped object 1 is held by the holding table 52 with the new adhesive tape 9 interposed therebetween.

[0080] Then, the back face lb side of the plate-shaped object 1 is cut by the cutting tool 78 as in the first groove forming step S10, and a plurality of second grooves 5 along the second direction 15 crossing the first direction 13 are formed on the back face lb of the plate-shaped object 1. Here, the front face la and the back face lb of the plate-shaped object 1 are not distinguished. For example, the face on which the grooves are first formed is the front face la, and the face on which the grooves are subsequently formed is the back face lb.

[0081] Also, the orientations of the first direction 13 and the second direction 15 are set so that the first grooves 3 and the second grooves 5 are not parallel to each other. In the drawings, the first direction 13 and the second direction 15 are perpendicular, and the first grooves 3 and the second grooves 5 are perpendicular, but the manufacturing method of the holding table of the present embodiment is not limited thereto. That is, as long as the first direction 13 and the second direction 15 are set so that the first grooves 3 and the second grooves 5 are not parallel to each other and the intersection points of the first grooves 3 and the second grooves 5 are formed when the plate-shaped object 1 is viewed from above.

[0082] Figure 5 (A) is a plan view schematically showing a portion of the front face la side of the plate-shaped object 1 on which the first grooves 3 and the second grooves 5 are formed, enlarged, Figure 5 (B) is a cross-sectional view schematically showing a portion of the plate-shaped object 1 on which the first grooves 3 and the second grooves 5 are formed, enlarged. Here, the depth of the second grooves 5 formed by the second groove forming step S20 is as described above. That is, it is set so that the sum of the depth of the first grooves 3 and the depth of the second grooves 5 is greater than the thickness of the plate-shaped object 1.

[0083] In this case, at each of the intersection points of the first grooves 3 and the second grooves 5, the bottoms of the first grooves 3 and the second grooves 5 communicate with each other to form a communication path 17 connecting the front face la side and the back face lb side of the plate-shaped object 1. Also, on the front face la side and the back face lb side of the plate-shaped object 1, gas can pass in and out through the communication path 17. On the other hand, each of the first grooves 3 and the second grooves 5 does not reach the side face lc of the plate-shaped object 1. Therefore, the gas passing through the communication path 17 does not leak to the side face lc side of the plate-shaped object 1.

[0084] Further, depths of the first grooves 3 and the second grooves 5 are preferably set in consideration of accuracy and deviation in cutting performed by the first groove forming step S10 and the second groove forming step S20. For example, in a case where the plate-like object 1 is a silicon wafer having a thickness of 780 μm, half of the thickness is 390 μm, but it is preferable that the depths of the first grooves 3 and the second grooves 5 are formed to be deeper than 390 μm by several tens of μm or so, respectively. Thereby, at the intersection of the first grooves 3 and the second grooves 5, the first grooves 3 and the second grooves 5 can be reliably connected.

[0085] Further, widths of the first grooves 3 and the second grooves 5 can be 10 μm or more, and preferably several hundreds of μm or so, respectively, so as to be stably formed in the plate-like object 1 at a prescribed depth. The widths of the first grooves 3 and the second grooves 5 reflect a blade thickness of the cutting edge 78b of the cutting tool 78. When the cutting tool 78 having the cutting edge 78b having a blade thickness that makes the widths of the first grooves 3 and the second grooves 5 such widths is used, the first grooves 3 and the second grooves 5 can be stably formed.

[0086] Further, the plurality of first grooves 3 and the plurality of second grooves 5 can be formed at equal intervals, and the intervals can be 0.5 mm or more and 10 mm or less. When the plurality of first grooves 3 and the plurality of second grooves 5 are formed at equal intervals in the plate-like object 1, in the entire area of the plate-like object 1, the negative pressure described later is uniformly transmitted between the front surface la and the back surface lb.

[0087] Further, the depths and the intervals of the first grooves 3 and the second grooves 5 are not limited to this, and are appropriately determined in a manner corresponding to the kind or the size of the workpiece to be attracted and held by the manufactured holding stage 10, the size of the negative pressure desired to be applied to the workpiece, and the like. Further, the depths and the intervals of the first grooves 3 and the second grooves 5, the number, and the like can be selected in a manner that becomes a performance suitable for processing performed by a device in which the holding stage 10 is assembled.

[0088] In the manufacturing method of the holding stage of the present embodiment, the plate-like object 1 in which the plurality of first grooves 3 and the plurality of second grooves 5 are formed is prepared in a number required to form the suction plate 19 described later. That is, in a case where the preparation of the plate-like object 1 is not completed in the required number (S30, refer to Figure 12 ), the first groove forming step S10 and the second groove forming step S20 are repeatedly performed to prepare the plate-like object 1 in the required number. In a case where the plate-like object 1 in which the plurality of first grooves 3 and the plurality of second grooves 5 are formed is prepared in the required number (S30, refer to Figure 12 ), a next step is entered.

[0089] Next, the suction plate forming step S50 of superimposing the plurality of plate-like objects 1 in which the plurality of first grooves 3 and the plurality of second grooves 5 are formed, respectively, and integrating the plurality of plate-like objects 1 to form the suction plate is performed. Figure 6(A) is a perspective view schematically showing the overlapping of multiple plate-shaped objects 1. Figure 6 (B) is a schematic perspective view showing the formed attraction plate 19.

[0090] In the suction plate forming step S50, multiple plate-shaped objects 1 are first overlapped. Here, the thickness of the formed suction plate 19 can be determined based on the number of overlapping plate-shaped objects 1. The number of plate-shaped objects 1 is determined according to the requirement that a frame 12 (described later) can be formed. Figure 8 (A) etc.) storage recess 86 (refer to) Figure 8 The depth of the suction plate 19 can be determined by the method of (A) etc.

[0091] In addition, Figure 6 In (A), the front 1a side of each plate 1 faces upward and the back 1b side faces downward, and the orientation of the first groove 3 and the second groove 5 formed on each plate 1 are the same. However, the manufacturing method of the holding table in this embodiment is not limited to this. After the suction plate 19 is formed, the performance of the plate 1 does not change due to the orientation of the front 1a side and the back 1b side, nor does the performance of the plate 1 change due to the orientation of the first groove 3 and the second groove 5. Therefore, there is no need to specifically control the orientation of each plate 1.

[0092] In the absorption plate forming step S50, after overlapping multiple plate-shaped objects 1, the multiple plate-shaped objects 1 are integrated. The multiple plate-shaped objects 1 can be integrated, for example, by a direct bonding technique. Before overlapping the multiple plate-shaped objects 1, an acid or other chemical solution is applied to the front side 1a and back side 1b of each plate-shaped object 1 to form a thin oxide film on the front side 1a and back side 1b, and to expose hydroxyl groups.

[0093] Next, when other plate-shaped materials 1 are stacked on top of one plate-shaped material 1, the two plate-shaped materials 1 bond together. This is believed to be because hydrogen bonds are formed between the hydroxyl groups on the facing surfaces of the two plate-shaped materials 1. Furthermore, when the laminate of the bonded multiple plate-shaped materials 1 is heated to a temperature of 400°C or higher, water molecules detach from the bonding surfaces, and the individual plate-shaped materials 1 are bonded more firmly. In particular, when the laminate of the multiple plate-shaped materials 1 is heated to around 1000°C, the individual plate-shaped materials 1 are bonded to the same extent as the bonds (interatomic bonds, etc.) contained in the materials constituting each plate-shaped material 1 (such as silicon).

[0094] Furthermore, multiple plates 1 can be integrated using a method that does not require heating. For example, two plates 1 to be integrated are moved into a vacuum chamber, and surface treatment is performed on the surfaces of each plate 1 to be joined inside the vacuum chamber. This surface treatment, for example, is argon ion sputtering, which is a process that activates the atoms constituting the outer surface of the plate 1 to improve reactivity.

[0095] Then, when the two plate-like objects 1 are brought into contact within the vacuum chamber, bonds are generated between atoms constituting the outer surfaces of the two plate-like objects 1, and the two plate-like objects 1 are firmly joined. Also, when the joining of the plate-like objects 1 is repeatedly performed within the vacuum chamber, the attraction plate 19 can be formed. In addition, the attraction plate formation step S50 is not limited to this, and can be performed by various existing methods such as thermal compression bonding. However, in the case where a plurality of plate-like objects 1 are joined to be integrated, each plate-like object 1 needs a face having extremely high flatness.

[0096] When the attraction plate formation step S50 is performed, the attraction plate 19 integrated by a plurality of plate-like objects 1 is formed. At this time, the first groove 3 or the second groove 5 of each plate-like object 1 is connected to the first groove 3 or the second groove 5 of the other plate-like object 1 adjacent thereto. Thus, the front surface 19a side and the back surface 19b side of the attraction plate 19 are communicated.

[0097] In addition, around the first groove 3 and the second groove 5 formed by performing the first groove formation step S10 and the second groove formation step S20, a minute crack shape called a micro crack or a damage called a chipped edge is generated on the plate-like object 1. Therefore, before the plurality of plate-like objects 1 are integrated by performing the attraction plate formation step S50, the etching step S40 can be performed.

[0098] The etching step S40 can be performed after the first groove formation step S10 and the second groove formation step S20 are performed and before the attraction plate formation step S50 is performed. In the etching step S40, the plate-like object 1 is treated, for example, with a mixed solution of nitric acid and fluoric acid or the like. Thereby, the damage such as the micro crack or the chipped edge is removed from the plate-like object 1. In this case, the strength of each plate-like object 1 is improved, and the strength of the attraction plate 19 formed thereafter is also improved. In addition, the outer surface of each plate-like object 1 is cleaned, and the joining of the plurality of plate-like objects 1 becomes easy.

[0099] In the manufacturing method of the holding table of the present embodiment, after the etching step S40 and the attraction plate formation step S50 are performed, the housing step S60 is performed. Figure 8 (A) is a cross-sectional view schematically showing the housing step S60. In the housing step S60, the attraction plate 19 is housed in the housing recess 86 of the frame 12 in which the housing recess 86 is formed on the upper surface, and the holding table 10 is formed.

[0100] Here, the frame 12 in which the attraction plate 19 is housed in the housing step S60 is described. Figure 7 is a plan view schematically showing the frame 12. In addition, in Figure 8 (A) and Figure 8 (B) include a cross-sectional view schematically showing the frame 12. The frame 12 is, for example, a disc-shaped member formed of a material such as stainless steel or ceramic.

[0101] A housing recess 86 capable of housing the suction plate 19 is formed on the upper surface of the frame body 12. The housing recess 86 is a shape corresponding to the shape of the suction plate 19 and the plate-shaped article 1. For example, in the case where the plate-shaped article 1 is a circular plate, the housing recess 86 is formed as a circular region having a diameter slightly larger than the diameter of the plate-shaped article 1.

[0102] An attraction groove 90 and an attraction path 92 leading to the back surface side (lower surface side) of the frame body 12 are formed in the bottom of the housing recess 86. The attraction groove 90 is composed of, for example, a plurality of radial grooves 90a and a plurality of annular grooves 90b. The radial grooves 90a and the annular grooves 90b communicate with the attraction path 92. In addition, the main region of the bottom of the housing recess 86 in which the attraction groove 90 is not formed is a flat surface 94 having a uniform height. As described later, the flat surface 94 serves as a support surface that supports the suction plate 19.

[0103] In addition, the structure of the radial grooves 90a and the annular grooves 90b of the attraction groove 90 is not particularly limited, and the attraction groove 90 need not be composed of the radial grooves 90a and the annular grooves 90b. The attraction groove 90 can be structured in such a manner that negative pressure can be uniformly transmitted to the back surface 19b of the suction plate 19 as described later. In addition, it can be structured so as to be able to secure the shape of the flat surface 94 that supports the suction plate 19 with a sufficient width.

[0104] A plurality of through-holes 88 for fixing members such as bolts for screwing into a base (not shown) of a machining device or the like as a fixing destination to fix the holding workbench 10 manufactured by the manufacturing method of the holding workbench of the present embodiment are formed outside the housing recess 86 of the frame body 12.

[0105] When a circular plate-shaped porous member is housed in the housing recess 86 of the frame body 12, a conventional holding workbench can be manufactured, and the holding workbench 10 manufactured by the manufacturing method of the holding workbench of the present embodiment can be manufactured using the frame body 12 for housing the porous member in the conventional holding workbench. That is, the frame body 12 need not be a special product for housing the suction plate 19. Also, in the case of using the conventional frame body 12, in order to form the suction plate 19 in a thickness greater than the depth of the housing recess 86, the number of plate-shaped articles 1 constituting the suction plate 19 is determined.

[0106] In the housing step S60, the suction plate 19 is housed in the housing recess 86 of the frame body 12. In order to fix the suction plate 19 to the frame body 12, an adhesive material 96 can be provided in advance on the back surface 19b side of the suction plate 19 or the flat surface 94 of the bottom of the housing recess 86 of the frame body 12. When the suction plate 19 is housed in the housing recess 86 and fixed to the frame body 12, the holding workbench 10 can be manufactured. At this time, the upper portion of the suction plate 19 is exposed outside the housing recess 86, and the front surface 19a of the suction plate 19 is higher than the upper surface of the frame body 12.

[0107] The groove (second groove 5) formed on the lower surface (back surface Ib) of the plate-shaped article 1 on the back surface 19b of the suction plate 19 is connected to the suction groove 90 of the frame 12. Also, the suction path 92 of the frame 12 and the front surface 19a of the suction plate 19 are communicated by the first groove 3 and the second groove 5 of each plate-shaped article 1 constituting the suction plate 19 and the suction groove 90. That is, when the suction source (not shown) is connected to the lower end of the suction path 92, negative pressure is transmitted to the front surface 19a of the suction plate 19. At this time, other paths are closed, so that the negative pressure is not easily leaked.

[0108] The holding table 10 manufactured by implementing the housing step S60 is assembled to the processing device such as the grinding device 2 shown in Fig. 1. Figure 1 The grinding device 2 has a base (not shown) that supports the holding table 10. Also, when the holding table 10 is placed on the base and the fixing member such as a bolt is inserted into the through hole 88 and screwed into the fixing hole formed in the base, the holding table 10 can be fixed to the base of the grinding device 2. At this time, the lower end of the suction path 92 of the frame 12 is connected to the suction source (not shown) of the grinding device 2.

[0109] In the grinding device 2, before the silicon wafer or the like as a workpiece is placed on the holding table 10, self-grinding of grinding the upper surface of the holding table 10 using the grinding tool 42 is implemented. At this time, the suction plate 19 formed of the same raw material as the workpiece protrudes on the upper surface of the holding table 10, so that the grinding tool 42 grinds the suction plate 19. Therefore, the same grinding tool 42 can be used when the self-grinding is implemented and when the workpiece is ground, and there is no need to replace the grinding wheel 40.

[0110] Here, it is also possible to consider forming the porous member used in the conventional holding table 10 from the same raw material as the workpiece, but a complicated manufacturing process for forming the porous member is required. In contrast, in the manufacturing method of the holding table of the present embodiment, the plurality of plate-shaped articles 1 formed of the same raw material as the workpiece are integrated to manufacture the suction plate 19, and the suction plate 19 is housed in the frame 12 as in the conventional one, whereby the holding table 10 can be easily formed.

[0111] In particular, instead of forming the mutually connected deep grooves on the front surface and the back surface of the plate-shaped article having the same thickness as the suction plate 19, relatively shallow grooves are formed on the plate-shaped article 1 thinner than the suction plate 19 and the plurality of plate-shaped articles 1 are integrated to form the suction plate 19. The relatively shallow first groove 3 and the second groove 5 can be easily and stably formed.

[0112] As explained above, the method for manufacturing a holding table according to this embodiment enables the stable and easy manufacture of a holding table 10 that can effectively perform self-grinding using a grinding tool 42 for grinding a workpiece.

[0113] Furthermore, the present invention is not limited to the embodiments described above, and various modifications and implementations are possible. For example, in the above embodiments, the case where the plate-shaped object 1 constituting the suction plate 19 and the workpiece held by the holding table 10 are made of the same raw material was described, but it is not necessary for them to be exactly the same raw material as the workpiece. It is sufficient as long as the same grinding tool 42 can be used during self-grinding and grinding of the workpiece. That is, the plate-shaped object 1 is only required to be a raw material that can be ground using a grinding tool 42 capable of grinding the workpiece.

[0114] Furthermore, in the above embodiment, the case where the suction plate 19 is fixed to the frame 12 using adhesive material 96 in the storage step S60 has been described; however, one aspect of the present invention is not limited to this. That is, the suction plate 19 can be fixed to the frame 12 using other methods. Figure 9 This is a schematic top view showing the frame 12a that can be secured to the attraction plate 19 using other methods. Figure 10 (A) is a cross-sectional view schematically showing the case where the attraction plate 19 is housed in the frame 12a in the housing step S60.

[0115] and Figure 7 Unlike the frame 12 shown, a plurality of plate attraction paths 98 communicating with the flat surface 94 are formed in the frame 12a. These plate attraction paths 98 are independent of the attraction groove 90 and attraction path 92. Furthermore, each plate attraction path 98 leads to the lower surface of the frame 12. Alternatively, the plate attraction paths 98 merge inside the frame 12a and lead to the lower surface of the frame 12.

[0116] Figure 10 (B) is a schematic cross-sectional view showing the holding worktable 10a manufactured in the receiving step S60. In the receiving step S60, the suction plate 19 is received in the receiving recess 86 of the frame 12a, thereby forming the holding worktable 10a. The suction plate 19 is supported by a flat surface 94.

[0117] In the machining device such as the grinding device 2 assembled with the holding table 10a, another suction source (suction path) independent of and controllable from the suction source (suction path) connected to the suction path 92 is connected. Also, the suction plate 19 is suctioned by the other suction source or the like via the plate suction path 98, whereby the suction plate 19 can be fixed to the frame 12a. Therefore, in the housing step S60, it is not necessarily required to fix the suction plate 19 to the frame 12a. In this case, it is possible to replace only the suction plate 19 in the state where the frame 12a is fixed to the machining device such as the grinding device 2.

[0118] Further, in the above-described embodiment, a case where the first groove forming step S10 and the second groove forming step S20 are performed using the cutting device 44 (refer to Figure 2 ) is described. That is, a case where the first groove 3 is formed by cutting the front face la side of the plate-shaped article 1 with the circular ring-shaped cutting tool 78 and the second groove 5 is formed by cutting the back face lb side of the plate-shaped article 1 with the cutting tool 78 is described. However, one embodiment of the present application is not limited to this, and the first groove 3 and the second groove 5 can be formed in the plate-shaped article 1 by other methods.

[0119] Figure 11 is a perspective view schematically showing a laser processing device 100 capable of irradiating a laser beam to the plate-shaped article 1 to form the first groove 3 and the second groove 5 by ablation processing. That is, in the first groove forming step S10, a laser beam of a wavelength absorbed by the plate-shaped article 1 can be irradiated to the front face la side of the plate-shaped article 1 to form the first groove 3 by ablation processing. Further, in the second groove forming step S20, the laser beam can be irradiated to the back face lb side of the plate-shaped article 1 to form the second groove 5 by ablation processing.

[0120] Here, the laser processing device 100 is described. The laser processing device 100 has a base 102 that supports each constituent element. On the upper surface of the base 102, an X-axis direction moving unit 104 that moves a holding table 126 holding the plate-shaped article 1 in the X-axis direction and a Y-axis direction moving unit 114 that moves the holding table 126 in the Y-axis direction perpendicular to the X-axis direction are provided.

[0121] The X-axis direction moving unit 104 has a pair of X-axis rails 106 along the X-axis direction on the upper surface of the base 102. An X-axis moving table 108 is slidably mounted on the pair of X-axis rails 106. A nut portion (not shown) in which an X-axis ball screw 110 substantially parallel to the X-axis rails 106 is screwed is provided on the back face side of the X-axis moving table 108.

[0122] An X-axis pulse motor 112 is connected to one end of the X-axis ball screw 110. The X-axis ball screw 110 is rotated by the X-axis pulse motor 112, thereby causing the X-axis moving stage 108 to move along the X-axis guide rail 106 in the X-axis direction.

[0123] The Y-axis moving unit 114 has a pair of Y-axis guide rails 116 along the Y-axis direction on the upper surface of the X-axis moving stage 108. The Y-axis moving stage 118 is slidably mounted on the pair of Y-axis guide rails 116. A nut portion (not shown) is provided on the back side of the Y-axis moving stage 118, in which a Y-axis ball screw 120, which is substantially parallel to the Y-axis guide rails 116, is screwed.

[0124] A Y-axis pulse motor 122 is connected to one end of the Y-axis ball screw 120. The Y-axis pulse motor 122 rotates the Y-axis ball screw 120, thereby causing the Y-axis moving stage 118 to move along the Y-axis guide rail 116 in the Y-axis direction. A cover 124 and a holding table 126 for holding the plate 1 are provided on the upper surface of the Y-axis moving stage 118.

[0125] A plurality of clamps 130 are provided around the holding table 126 to hold the annular frame 7 of the frame unit 11. The holding table 126 has: a porous component 128 exposed on its upper surface; a suction path connected to the porous component 128 at one end; and a suction source connected to the other end of the suction path. When the suction source is activated, the plate 1 placed on the holding table 126 is attracted and held.

[0126] A laser beam irradiation unit 134 is provided above the holding table 126, capable of irradiating a laser beam onto the plate 1 held by the holding table 126. The laser beam irradiation unit 134 is supported by a support portion 132, which has a column extending upward from the rear upper surface of the base 102 and an arm extending upward from the upper end of the column toward the holding table 126.

[0127] The laser beam irradiation unit 134 includes: a laser oscillator (not shown) capable of emitting a laser beam of wavelength absorbed by the plate 1 (the plate 1 has an absorptive wavelength); and a focusing lens (not shown) capable of focusing the laser beam onto the upper surface of the plate 1.

[0128] In the first groove forming step S10, the frame unit 11 containing the plate-shaped object 1 is held using the holding stage 126. While moving the holding stage 126 in the X-axis or Y-axis direction, a laser beam is irradiated onto the front surface 1a of the plate-shaped object 1 from the laser beam irradiation unit 134. More specifically, the laser beam is focused on the front surface 1a from one end to the other of the predetermined forming line of the first groove 3 to perform ablation processing on the plate-shaped object 1. Thus, the first groove 3 can be formed.

[0129] Furthermore, if a first groove 3 of sufficient depth cannot be formed on the plate 1 using a single laser beam irradiation, the formed first groove 3 is further irradiated with a laser beam to perform multiple ablation processes, thereby deepening the first groove 3. In this way, the first groove 3 can be formed on the front side 1a of the plate 1. And, by similarly performing the second groove forming step S20, a second groove 5 can be formed on the back side 1b of the plate 1.

[0130] Thus, in one aspect of the manufacturing method of the holding table of the present invention, the first groove 3 and the second groove 5 can be formed by methods other than cutting by the cutting device 44, and the first groove 3 and the second groove 5 can be formed by ablation processing by the laser processing device 100.

[0131] Furthermore, in the above embodiments, the description mainly focuses on the case where a plurality of first grooves 3 are formed at equal intervals on the front side 1a of the plate-shaped object 1 and a plurality of second grooves 5 are formed at equal intervals on the back side 1b of the plate-shaped object 1. However, one aspect of the present invention is not limited to this. That is, the plurality of first grooves 3 and the plurality of second grooves 5 do not need to be formed at equal intervals on the plate-shaped object 1.

[0132] Depending on the formation position or number and formation density of the plurality of first grooves 3 and plurality of second grooves 5 in each plate 1, the properties of the plate 1 may sometimes change, and the properties of the attraction plate 19 composed of the plurality of plate 1 may sometimes change. When the first grooves 3 and second grooves 5 are equally spaced, for example, when the manufactured holding table 10 is assembled into the grinding apparatus 2 and self-grinding is performed to grind the front surface 19a of the attraction plate 19, grinding may sometimes be easier to perform at the center of the attraction plate 19.

[0133] When the ease of grinding varies depending on the position of the suction plate 19, even if self-grinding is performed, the front surface 19a of the suction plate 19 and the bottom surface of the rotating grinding wheel 42 will not be parallel. Thus, the purpose of self-grinding cannot be achieved. Therefore, the properties of each plate 1 can be adjusted by changing the formation position, number, and formation density of the plurality of first grooves 3 and the plurality of second grooves 5 in a manner that ensures the front surface 19a of the suction plate 19 is parallel to the bottom surface of the rotating grinding wheel 42 during self-grinding.

[0134] For example, the first grooves 3 and the second grooves 5 are formed on the plate 1 in such a way that one or both of the intervals between the plurality of first grooves 3 and the plurality of second grooves 5 are not constant, but become narrower the further away from the center of the plate 1. In this case, the ease of grinding is reduced at the center of the suction plate 19, and when self-grinding is performed using the grinding device 2, the front surface 19a of the suction plate 19 is parallel to the bottom surface of the grinding tool 42. That is, the purpose of self-grinding can be achieved. In this way, the properties of the suction plate 19 can be controlled by the formation positions of the first grooves 3 and the second grooves 5, etc.

[0135] The structure and method of the above embodiments can be appropriately modified and implemented as long as they do not depart from the scope of the purpose of the present invention.

Claims

1. A method for manufacturing a worktable, characterized in that, The method for manufacturing this holding table includes the following steps: The first groove forming step involves forming a plurality of first grooves along a first direction on the front side of the plate-shaped object; The second groove forming step involves flipping the plate-shaped object over and forming a plurality of second grooves on the back side of the plate-shaped object along a second direction that intersects the first direction. The suction plate forming step involves overlapping multiple plate-shaped objects, each having a plurality of first grooves and a plurality of second grooves respectively, and integrating the multiple plate-shaped objects to form a suction plate; and In the storage step, the suction plate is housed in the storage recess of a frame with a storage recess formed on its upper surface, thus forming a holding worktable. The first groove and the second groove do not reach the side of the plate-like object. The sum of the depths of the first groove and the second groove is greater than the thickness of the plate-like object, and the first groove and the second groove are interconnected. The thickness of the suction plate is greater than the depth of the receiving recess.

2. The method for manufacturing a holding worktable according to claim 1, characterized in that, In the first groove forming step, the first groove is formed by cutting the front side of the plate-shaped object using a circular cutting tool. In the second groove forming step, the second groove is formed by cutting the back side of the plate using the cutting tool.

3. The method for manufacturing a holding worktable according to claim 1, characterized in that, In the first groove forming step, a laser beam of a wavelength absorbed by the plate is irradiated onto the front side of the plate to form the first groove through ablation. In the second groove forming step, the laser beam is irradiated onto the back side of the plate to form the second groove by ablation.

4. The method for manufacturing a holding table according to any one of claims 1 to 3, characterized in that, In this storage step, the attraction plate is fixed to the storage recess of the frame using adhesive material.

5. The method for manufacturing a holding table according to any one of claims 1 to 3, characterized in that, The method for manufacturing the holding stage also includes an etching step: prior to the suction plate forming step, etching is performed on the front and back sides of each of the plurality of plate-shaped objects.

6. The method for manufacturing a holding table according to any one of claims 1 to 3, characterized in that, The plate-shaped object is made of the same raw material as the workpiece held by the holding table.

7. The method for manufacturing a holding table according to any one of claims 1 to 3, characterized in that, The further away from the center of the plate, the narrower one or both of the spacings of the first groove and the second groove.

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