Grinding device and creep feed grinding method

Abstract

To provide a grinding device, which dresses a grinding stone while suppressing work efficiency from deteriorating, in creep feed grinding.SOLUTION: A grinding device, which applies creep feed grinding to a workpiece, comprises: a chuck table having a holding surface for absorbing and holding the workpiece; a table base supporting the chuck table; a grinding unit that has a columnar spindle and makes a grinding wheel mounted on a lower end part of the spindle grind the workpiece held by the chuck table; a moving mechanism that moves the table base and the grinding unit relatively in a processing feeding direction; and a dress part, arranged in the table base or the chuck table, which dresses a grinding stone of the grinding wheel.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a grinding apparatus for performing creep feed grinding on a workpiece, and a creep feed grinding method for performing creep feed grinding on a workpiece. [Background technology]

[0002] Small and lightweight electronic devices such as mobile phones use semiconductor chips that include devices such as ICs (Integrated Circuits), LSIs (Large Scale Integration), etc. Semiconductor chips are manufactured, for example, by forming devices in each area defined by a plurality of planned division lines (streets) set on the surface of a wafer, and then cutting the wafer along each street.

[0003] In recent years, there has been a demand for thinning wafers by grinding, etc., in order to make semiconductor chips smaller and lighter. One method of grinding wafers is called creep feed grinding, in which a chuck table holding the wafer is moved horizontally relative to a grinding wheel that rotates at a predetermined height (see, for example, Patent Document 1).

[0004] When grinding a wafer using creep feed grinding, the front side of the wafer is first suction-held by a chuck table positioned so that it does not overlap the grinding wheel when viewed from above, leaving the back side of the wafer exposed.

[0005] Next, the grinding wheel is rotated and the lower surface of the grinding stone of the grinding wheel is positioned slightly lower than the back surface of the wafer.The grinding wheel and the chuck table are then moved relatively in the horizontal direction.The side and lower surfaces of the grinding stone come into contact with the upper surface of the wafer, thereby grinding the wafer.

[0006] In creep feed grinding, grinding is mainly performed on the side of the grinding wheel, so the underside of the grinding wheel is less likely to wear out than the side. Also, when the workpiece to be ground contains materials that are prone to clogging the grinding wheel, such as workpieces coated with mold resin or wafers coated with metal films, grinding becomes relatively difficult.

[0007] In particular, creep feed grinding is more prone to clogging than in infeed grinding because wear of the grinding wheel is less likely to progress. To eliminate clogging of the grinding wheel, it is necessary to dress the grinding wheel. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-28550 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in order to perform dressing, it is necessary to suction-hold a dressing board on the chuck table instead of the workpiece, which is held by suction on the chuck table. This type of workpiece-to-dressing board replacement work reduces work efficiency.

[0010] The present invention has been made in view of the above problems, and has as its object to dress a grinding wheel while suppressing a decrease in work efficiency in creep feed grinding. [Means for solving the problem]

[0011] According to one aspect of the present invention, a grinding apparatus for performing creep feed grinding on a workpiece includes a chuck table having a holding surface for suction-holding the workpiece, a table base supporting the chuck table, a grinding unit having a cylindrical spindle and for grinding the workpiece held by the chuck table with a grinding wheel attached to a lower end of the spindle, a movement mechanism for relatively moving the table base and the grinding unit in a processing feed direction, a dressing section disposed on the table base or the chuck table for dressing a grinding stone of the grinding wheel, and a control unit for controlling the grinding unit and the movement mechanism so as to grind the workpiece to a finishing thickness by creep feed grinding using a plurality of processing feeds, wherein the control unit executes dressing of the grinding stone at a predetermined timing between processing feeds among the plurality of processing feeds, The dressing portion is on the table base and not on the chuck table, and When the chuck table is disposed at a position closer to the grinding unit than the dressing portion in the processing feed direction, an upper surface of the dressing portion is higher than the holding surface of the chuck table, The dressing portion is on the table base and not on the chuck table, and A grinding device is provided in which, when the dressing portion is positioned closer to the grinding unit than the chuck table in the processing feed direction, the holding surface of the chuck table is higher than the upper surface of the dressing portion, and when the dressing portion is on the chuck table and the holding surface of the chuck table is positioned closer to the grinding unit than the dressing portion in the processing feed direction, the upper surface of the dressing portion is higher than the holding surface of the chuck table.

[0012] According to another aspect of the present invention, there is provided a creep feed grinding method, comprising: a holding step of holding a workpiece on a holding surface of a chuck table; a creep feed grinding preparation step of positioning a lower surface of a grinding stone of a grinding wheel below an upper surface of the workpiece after the holding step, with the grinding wheel for grinding the workpiece separated from the chuck table in a processing feed direction; and a creep feed grinding preparation step of moving the workpiece and the rotating grinding wheel relatively in the processing feed direction after the creep feed grinding preparation step. Applicablea creep feed grinding step for grinding the entire upper surface; a dressing preparation step for positioning the lower surface of the grinding wheel below the upper surface of a dressing section for dressing the grinding wheel after the creep feed grinding step; and a dressing step for grinding the entire upper surface of the dressing section by moving the dressing section and the rotating grinding wheel relatively in the processing feed direction after the dressing preparation step, wherein when the workpiece is ground to a finishing thickness by a plurality of creep feed grinding steps, the dressing preparation step and the dressing step are performed at predetermined timings between the creep feed grinding steps, and the dressing section is disposed on the chuck table or on a table base on which the chuck table is supported, The dressing portion is on the table base and not on the chuck table, and When the chuck table is disposed at a position closer to a grinding unit including the grinding wheel than the dressing portion in the processing feed direction, the upper surface of the dressing portion is higher than the holding surface of the chuck table, The dressing portion is on the table base and not on the chuck table, and A creep feed grinding method is provided in which, when the dressing portion is positioned closer to the grinding unit than the chuck table in the processing feed direction, the upper surface of the workpiece held by suction on the holding surface of the chuck table is higher than the upper surface of the dressing portion, and when the dressing portion is on the chuck table and the holding surface of the chuck table is positioned closer to the grinding unit than the dressing portion in the processing feed direction, the upper surface of the dressing portion is higher than the holding surface of the chuck table. [Effects of the Invention]

[0013] A grinding apparatus according to one aspect of the present invention includes a dressing unit for dressing the grinding stone of the grinding wheel, the dressing unit being disposed on a table base that supports the chuck table or on the chuck table.

[0014] Therefore, by moving the dressing unit and the table base relative to each other in the processing feed direction, the grinding wheel can be dressed by the dressing unit in the same way as when creep feed grinding is performed on a workpiece. In this way, since there is no need to replace the workpiece with the dressing board, the grinding wheel can be dressed while suppressing a decrease in work efficiency in creep feed grinding. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a partial cross-sectional side view of the grinding device. [Figure 2] FIG. 1 is a flow diagram of a creep feed grinding method. [Figure 3] FIG. [Figure 4] FIG. 10 shows a creep feed grinding preparation step. [Figure 5] FIG. 1 illustrates a creep feed grinding step. [Figure 6] FIG. 10 is a diagram showing a dress preparation step. [Figure 7] FIG. [Figure 8] 10A and 10B are diagrams illustrating a dressing portion according to a modified example. [Figure 9] FIG. 9(A) is a top view of the dressing section and the like according to the second embodiment, and FIG. 9(B) is a partial cross-sectional side view of the chuck table, dressing section and the like according to the second embodiment. [Figure 10] FIG. 10 is a top view of a dressing portion and the like according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a partial cross-sectional side view of a grinding apparatus 2 according to a first embodiment. The X-axis direction, Y-axis direction, and Z-axis direction (vertical direction) shown in Fig. 1 are orthogonal to one another.

[0017] In this embodiment, the direction that is approximately parallel to the X-axis direction and that proceeds from the front position A1 to the rear position A2 of the grinding device 2 is referred to as the processing feed direction B. The front position A1 is, for example, a position for carrying in and out the workpiece 11 (see FIG. 3), and the rear position A2 is, for example, a processing position where grinding is performed on the workpiece 11. Also, in this embodiment, the downward direction along the Z-axis direction is referred to as the grinding feed direction.

[0018] The grinding device 2 has a base 4 that supports each of the components. A pair of guide rails (not shown) that are arranged along the X-axis direction are provided on the upper surface of the base 4. A table base 6 that is rectangular in top view is slidably attached to the guide rails.

[0019] A nut portion 8 is provided on the underside of the table base 6. A ball screw 10, which is disposed substantially parallel to the X-axis direction, is rotatably connected to the nut portion 8. A pulse motor 12 is connected to one end of the ball screw 10, and a bearing 14 is connected to the other end of the ball screw 10.

[0020] When the ball screw 10 is rotated by the pulse motor 12, the table base 6 moves along the X-axis direction. The pair of guide rails, the ball screw 10, the pulse motor 12, etc. constitute a movement mechanism 16 for moving the table base 6 in the processing feed direction B relative to the grinding unit 30, which will be described later.

[0021] A chuck table 18, which is circular in top view, is supported and fixed on the upper surface of the table base 6. The chuck table 18 has a disk-shaped frame body 20 made of ceramics. A circular recess having a predetermined depth is formed in the center of the frame body 20.

[0022] A predetermined flow path is formed in the frame 20. One end of this flow path is connected to a suction source (not shown) such as an ejector, and the other end of this flow path is exposed to the recess. A circular porous plate 22 made of porous ceramics and having approximately the same diameter as the recess is fixed to the recess.

[0023] The upper surface of the frame 20 and the upper surface of the porous plate 22 are substantially flush with each other. When the suction source is operated, negative pressure is transmitted to the holding surface 18a via a predetermined flow path. The negative pressure generated on the holding surface 18a sucks and holds the workpiece 11 (see FIG. 3).

[0024] In this embodiment, the workpiece 11 is a wafer made of a semiconductor material such as silicon. A plurality of streets (not shown) are set in a grid pattern on the surface 11a (see FIG. 4) of the workpiece 11, and devices (not shown) such as ICs are formed in each area defined by the plurality of streets.

[0025] Before grinding the workpiece 11, a protective tape (not shown) is attached to the front surface 11a to prevent damage to the device, etc. Then, the back surface 11b is ground while the front surface 11a is held by suction on the holding surface 18a via the protective tape.

[0026] 1, a cylindrical holder 24 is fixed to the upper surface of the table base 6 in front of an end position C in the processing feed direction B of the chuck table 18 (i.e., in the opposite direction to the processing feed direction B). The holder 24 in this example is disposed in front of the front end position of the chuck table 18.

[0027] A disk-shaped dressing portion 26 having a diameter smaller than that of the holding surface 18a is fixed to the upper part of the holder 24. The dressing portion 26 protrudes about 1 mm from the upper end of the holder 24. The dressing portion 26 has abrasive grains such as white alundum (WA) or green carbon (GC) and a bond (binding material) for fixing the abrasive grains, such as a vitrified bond or a resin bond.

[0028] The dressing portion 26 is used to dress a grinding stone 48b of a grinding wheel 48, which will be described later. An upper surface 26a of the dressing portion 26 is disposed at a predetermined position higher than the back surface 11b of the workpiece 11, which is suction-held by the holding surface 18a.

[0029] In this embodiment, the holder 24 does not move the height position of the upper surface 26a of the dress portion 26 along the Z-axis direction, but if an actuator (not shown) is built into the holder 24, the height position of the upper surface 26a may be moved by this actuator by several μm to approximately 10 μm along the Z-axis direction.

[0030] A wall 28 extending in the Z-axis direction is provided on the rear position A2 side of the base 4. A grinding feed mechanism 32 for moving the grinding unit 30 along the Z-axis direction is provided on the front side surface of the wall 28.

[0031] The grinding feed mechanism 32 has a pair of guide rails 34, each arranged along the Z-axis direction. Note that Fig. 1 shows one of the guide rails 34. A moving block 34a is slidably attached to the guide rail 34. A nut portion 36 is provided on the rear side surface of the moving block 34a.

[0032] A ball screw 38, which is disposed substantially parallel to the Z-axis direction, is rotatably connected to the nut portion 36. A pulse motor 40 is connected to the upper end of the ball screw 38, and a bearing is connected to the lower end of the ball screw 38. When the pulse motor 40 rotates the ball screw 38, the moving block 34a moves along the Z-axis direction.

[0033] The grinding unit 30 is fixed to the moving block 34a via a fixture 34b. The grinding unit 30 has a cylindrical spindle housing 42 arranged along the Z-axis direction. A cylindrical spindle 44 is rotatably housed in the spindle housing 42.

[0034] A motor (not shown) is provided at the upper end of the spindle 44. The lower end of the spindle 44 protrudes downward from the bottom of the spindle housing 42, and the center of a disk-shaped mount 46 is fixed to the lower end of the spindle 44.

[0035] An annular grinding wheel 48 is attached to the underside of the mount 46. The grinding wheel 48 has an annular wheel base 48a made of metal. A plurality of grinding stones 48b are arranged at predetermined intervals on the underside of the wheel base 48a along the circumferential direction of the wheel base 48a (see FIG. 3).

[0036] Each grinding wheel 48b has abrasive grains such as diamond, cBN (cubic boron nitride), etc., and a binder that secures the abrasive grains, such as metal, ceramics, resin, etc. A grinding water nozzle 50 is provided at the lower front portion of the grinding unit 30 to supply grinding water such as pure water to the contact area between the grinding wheel 48b and the workpiece 11 during grinding.

[0037] The grinding device 2 is provided with a control unit (not shown) that controls the operations of the moving mechanism 16, the grinding feed mechanism 32, the grinding unit 30, the grinding water nozzle 50, etc. The control unit is configured by a computer including, for example, a processor (processing device) represented by a CPU (Central Processing Unit), a main storage device such as a DRAM (Dynamic Random Access Memory), and an auxiliary storage device such as a flash memory.

[0038] The auxiliary storage device stores software including a predetermined program. The functions of the control unit are realized by operating the processor in accordance with this software. Next, a creep feed grinding method using the grinding device 2 will be described with reference to Figures 2 to 6.

[0039] 2 is a flow diagram of the creep feed grinding method according to this embodiment. In this embodiment, the creep feed grinding method shown in FIG. 2 is executed by operating the grinding device 2 in accordance with a program stored in the auxiliary storage device.

[0040] First, the chuck table 18 is positioned at the front position A1, so that the chuck table 18 is separated from the grinding wheel 48 in the processing feed direction B (see FIG. 3). Then, the workpiece 11 is placed on the holding surface 18a so that the back surface 11b is exposed upward and the front surface 11a to which a protective tape (not shown) is attached is positioned downward.

[0041] Thereafter, a negative pressure is generated on the holding surface 18a, and the workpiece 11 is suction-held on the holding surface 18a via the protective tape (holding step S10). Figure 3 is a diagram showing the holding step S10. Note that the moving block 34a, spindle housing 42, mount 46, wheel base 48a, etc. are omitted from Figure 3.

[0042] After the holding step S10, the height position of the grinding wheel 48 is adjusted (creep feed grinding preparation step S20). Figure 4 is a diagram showing the creep feed grinding preparation step S20.

[0043] In the creep feed grinding preparation step S20, with the grinding wheel 48 separated from the chuck table 18 in the processing feed direction B, the grinding wheel 48 is rotated at, for example, 6000 rpm, and the lower surface 48b1 of the grinding wheel 48b is positioned below the back surface (upper surface) 11b of the workpiece 11.

[0044] For example, when grinding the workpiece 11 to the finishing thickness in 10 processing feeds, in the creep feed grinding preparation step S20, the position of the lower surface 48b1 of the grinding wheel 48b is adjusted to a height position corresponding to approximately 1 / 10 of the finishing thickness.

[0045] After the creep feed grinding preparation step S20, the rotating grinding wheel 48 and the workpiece 11 are moved relative to each other in the processing feed direction B to grind the entire back surface 11b (top surface) of the workpiece 11 (creep feed grinding step S30).

[0046] 5 is a diagram showing the creep feed grinding step S30. For example, in the creep feed grinding step S30, the table base 6 is fed at 10 mm / sec along the feed direction B while spraying grinding water from the grinding water nozzle 50 at a predetermined flow rate of 4 l / min or more and 8 l / min or less.

[0047] After the entire back surface 11b is ground in the first creep feed grinding, the table base 6 is moved in the direction opposite to the processing feed direction B and returned to the front position A1. Then, a second creep feed grinding is performed. In this manner, the creep feed grinding step S30 is performed multiple times until the workpiece 11 reaches the finishing thickness.

[0048] However, in creep feed grinding, wear of the grinding wheel 48b is less likely to progress than in in-feed grinding, and clogging is more likely to occur. Therefore, in this embodiment, the grinding wheel 48b is dressed at a predetermined timing.

[0049] For example, when grinding the workpiece 11 to the finishing thickness in 10 processing feeds, immediately after the 2nd, 4th, 6th and 8th processing feeds (i.e., at the dressing timing), the processing feed amount of the table base 6 is increased from the processing feed amount of the first time, so that the dressing section 26 dresses the grinding wheel 48b.

[0050] The dressing timing may be determined in a program stored in an auxiliary storage device, or may be set by an operator in the control unit using a display input unit (not shown) such as a touch panel before creep feed grinding begins.

[0051] After creep feed grinding step S30, if the workpiece 11 has reached the finishing thickness (YES in S40), creep feed grinding is terminated. However, at the end of the first creep feed grinding, the finishing thickness has not yet been reached (NO in S40), so the control unit then determines whether it is time to dress.

[0052] If it is not time to dress (NO in S50), the process returns to creep feed grinding preparation step S20. On the other hand, if it is time to dress (YES in S50), the lower surface 48b1 of the grinding wheel 48b is positioned lower than the upper surface 26a of the dressing portion 26 relative to the grinding wheel 48b (dress preparation step S60).

[0053] 6 is a diagram showing the dressing preparation step S60. In the dressing preparation step S60 of this embodiment, the height position of the lower surface 48b1 is adjusted while the table base 6 is being processed immediately after the second processing feed. However, in the dressing preparation step S60, the height position of the lower surface 48b1 may be adjusted while the processing feed of the table base 6 is temporarily stopped.

[0054] After the dressing preparation step S60, the dressing portion 26 and the rotating grinding wheel 48 are moved relative to each other in the processing feed direction B, thereby grinding the entire upper surface 26a of the dressing portion 26 (dressing step S70). Figure 7 is a diagram showing the dressing step S70.

[0055] When the grinding wheel 48 rotates, a circular region is formed by the locus of the lower surface 48b1 of each grinding stone 48b. In the dressing step S70, the table base 6 is moved in the processing feed direction B at least until the upper surface 26a of the dressing portion 26 moves from outside to inside the circular region. After the dressing step S70, the process returns to the creep feed grinding preparation step S20.

[0056] In this embodiment, by moving the dressing portion 26 and the table base 6 relative to each other in the processing feed direction B, the grinding wheel 48b can be dressed by the dressing portion 26 in the same way as creep feed grinding is performed on the workpiece 11.

[0057] Therefore, in this embodiment, there is no need to replace the workpiece 11 with a dressing board for dressing the grinding wheel 48b. Therefore, in creep feed grinding, the grinding wheel 48b can be dressed while suppressing a decrease in work efficiency.

[0058] Next, a modified example of the first embodiment will be described. Fig. 8 is a diagram showing a dressing section 26 according to the modified example. In Fig. 8, the position of the dressing section 26 in the first embodiment is indicated by a dashed line on the top surface of the table base 6.

[0059] The dressing portion 26 in the modified example is located further rearward than the position of the dressing portion 26 in the first embodiment, and is shifted in the Y-axis direction from a straight line D (shown by a dotted line in Figure 8) that passes through the center 18b of the holding surface 18a and is parallel to the processing feed direction B.

[0060] However, the position of the dressing portion 26 is adjusted appropriately so that the creep feed grinding step S30 and the dressing step S70 are not performed simultaneously. In this modified example, the grinding wheel 48b can be dressed in the same way as in the first embodiment.

[0061] Next, a second embodiment will be described. Fig. 9(A) is a top view of the dressing unit 26 and other components according to the second embodiment, and Fig. 9(B) is a partial cross-sectional side view of the chuck table 18, the dressing unit 26, and other components according to the second embodiment.

[0062] In the second embodiment, the cylindrical holder 24a (see Figure 9(B)) is fixed on the upper surface of the table base 6 behind the end position C of the chuck table 18 in the processing feed direction B (i.e., in the processing feed direction B) (see Figure 9(A)).

[0063] A disk-shaped dressing portion 26 is fixed to the upper portion of the holder 24a. However, since the holder 24a is shorter than the holder 24 of the first embodiment, the upper surface 26a of the dressing portion 26 is located lower than the holding surface 18a (see FIG. 9(B)).

[0064] In addition, the upper surface 26a of the dressing portion 26 may be positioned higher than the holding surface 18a, as long as the front surface 11a is positioned lower than the back surface 11b of the workpiece 11 held by suction on the holding surface 18a.

[0065] In this embodiment, the holder 24a does not move the height position of the upper surface 26a of the dress portion 26 along the Z-axis direction, but if an actuator (not shown) is built into the holder 24, the height position of the upper surface 26a may be moved along the Z-axis direction by this actuator.

[0066] In this embodiment, the dressing portion 26 and the table base 6 are moved relative to each other in the processing feed direction B, so that the grinding wheel 48b can be dressed by the dressing portion 26 in the same way as creep feed grinding is performed on the workpiece 11.

[0067] Therefore, there is no need to replace the workpiece 11 with a dressing board for dressing the grinding wheel 48b, so that the grinding wheel 48b can be dressed while suppressing a decrease in work efficiency in creep feed grinding.

[0068] Next, a third embodiment will be described. Fig. 10 is a top view of a dressing part 26 according to the third embodiment. In the third embodiment, the workpiece 21 to be ground is not a disk-shaped wafer but a rectangular plate-shaped package substrate.

[0069] The workpiece 21 includes, for example, a plurality of QFN (Quad Flat No-Lead) packages, each having a leadless structure. The workpiece 21 has a plate-shaped base substrate 21a. The base substrate 21a is formed of a metal such as 42 alloy (an alloy of iron and nickel) or copper.

[0070] A plurality of streets (not shown) are set in a grid pattern on the front surface of the base substrate 21a so as to intersect with each other, and a device chip (not shown) including a device such as an IC is disposed in each of the areas defined by the plurality of streets.

[0071] A plurality of (for example, nine) device chips are sealed with one resin layer (i.e., mold resin layer) 21d. 10 Workpiece shown in 21In the example, three resin layers 21b are provided along the longitudinal direction of a base substrate 21a.

[0072] Each resin layer 21b protrudes beyond the rear surface of the base substrate 21a on the rear surface side of the base substrate 21a. The front surface side of the workpiece 21 is suction-held by a disk-shaped chuck table 52. A substantially rectangular recess having a longitudinal portion in the Y-axis direction is formed on the substantially flat upper surface of the chuck table 52.

[0073] A plate-shaped porous plate (not shown) having substantially the same shape as the recess is fixed in this recess. The upper surface of the porous plate is substantially flush with the upper surface of the chuck table 52. Negative pressure is transmitted to the porous plate from a suction source (not shown) such as an ejector via a predetermined flow path. Therefore, the upper surface of the porous plate functions as a holding surface 52a that holds the workpiece 21 by suction.

[0074] A cylindrical holder (not shown) is fixed to the upper surface of the chuck table 52, ahead of the end position C of the chuck table 52 in the processing feed direction B (i.e., in the opposite direction to the processing feed direction B), and a disk-shaped dressing portion 26 is fixed to the top of this holder.

[0075] In the creep feed grinding method of the third embodiment, the entire upper surface of the resin layer 21b exposed upward is ground while the surface side of the base substrate 21a is held by suction with the holding surface 52a, according to the flow diagram shown in Figure 2.

[0076] The third embodiment also eliminates the need to replace the workpiece 21 with a dressing board for dressing the grinding wheel 48b. Therefore, in creep feed grinding, the grinding wheel 48b can be dressed while suppressing a decrease in work efficiency.

[0077] The dressing part 26 may be held by suction via a circular porous plate (not shown) formed on the upper surface of the chuck table 52, without using a holder. The dressing part 26 may also be placed on the table base 6, as shown in FIGS. 3 and 8.

[0078] In addition, the structures, methods, etc. according to the above-described embodiments can be appropriately modified and implemented without departing from the scope of the present invention. In the above-described embodiment, a disk-shaped dressing portion 26 is used, but a rectangular plate-shaped or other shaped dressing portion 26 may also be used.

[0079] The arrangement of the dressing unit 26 is not limited to the above-described embodiment and modified examples. The dressing unit 26 may be arranged on the relative movement path of the table base 6 or the chuck table 52 and the grinding wheel 48 when the grinding apparatus 2 is viewed from above. [Explanation of symbols]

[0080] 2: Grinding device, 4: Base, 6: Table base, 8: Nut, 10: Ball screw 11: Workpiece, 11a: Front surface, 11b: Back surface 12: Pulse motor, 14: Bearing, 16: Moving mechanism 18: chuck table, 18a: holding surface, 18b: center 20: Frame, 22: Porous plate 21: Workpiece, 21a: Base substrate, 21b: Resin layer 24, 24a: holder, 26: dressing part, 26a: upper surface 28: Wall portion, 30: Grinding unit, 32: Grinding feed mechanism 34: guide rail, 34a: moving block, 34b: fixing device 36: Nut part, 38: Ball screw, 40: Pulse motor 42: Spindle housing, 44: Spindle, 46: Mount 48: Grinding wheel, 48a: Wheel base, 48b: Grinding stone, 48b1: Lower surface 50: Grinding water nozzle 52: chuck table, 52a: holding surface A1: Front position, A2: Back position, B: Machining feed direction, C: End position

Claims

1. A grinding apparatus for performing creep feed grinding on a workpiece, comprising: a chuck table having a holding surface for suction-holding the workpiece; a table base that supports the chuck table; a grinding unit having a cylindrical spindle, the workpiece held by the chuck table being ground by a grinding wheel attached to a lower end of the spindle; a movement mechanism that moves the table base and the grinding unit relatively in a processing feed direction; a dressing unit disposed on the table base or the chuck table for dressing the grinding stone of the grinding wheel; a control unit for controlling the grinding unit and the moving mechanism so that the workpiece is ground to a finish thickness by creep feed grinding using a plurality of processing feeds; Equipped with the control unit executes dressing of the grinding wheel at a predetermined timing between the processing feeds among the plurality of processing feeds; When the dressing portion is on the table base and not on the chuck table, and the chuck table is disposed at a position closer to the grinding unit than the dressing portion in the processing feed direction, the upper surface of the dressing portion is higher than the holding surface of the chuck table, When the dressing portion is on the table base and not on the chuck table, and when the dressing portion is disposed at a position closer to the grinding unit than the chuck table in the processing feed direction, the holding surface of the chuck table is higher than the upper surface of the dressing portion, A grinding device characterized in that, when the dressing portion is on the chuck table and the holding surface of the chuck table is positioned closer to the grinding unit than the dressing portion in the processing feed direction, the upper surface of the dressing portion is higher than the holding surface of the chuck table.

2. 1. A creep feed grinding method comprising: a holding step of holding the workpiece on a holding surface of a chuck table; a creep feed grinding preparation step in which, after the holding step, a grinding wheel for grinding the workpiece is separated from the chuck table in a processing feed direction, and a lower surface of a grinding stone of the grinding wheel is positioned below an upper surface of the workpiece; a creep feed grinding step of grinding the entire upper surface of the workpiece by moving the workpiece and the rotating grinding wheel relatively in the processing feed direction after the creep feed grinding preparation step; a dressing preparation step of positioning a lower surface of the grinding wheel below an upper surface of a dressing section for dressing the grinding wheel after the creep feed grinding step; a dressing step of grinding the entire upper surface of the dressing part by moving the dressing part and the rotating grinding wheel relative to each other in the processing feed direction after the dressing preparation step; Equipped with When grinding the workpiece to a finishing thickness by performing the creep feed grinding step a plurality of times, the dressing preparation step and the dressing step are performed at predetermined timings between the creep feed grinding steps; the dressing unit is disposed on a table base on which the chuck table is supported or on the chuck table, When the dressing portion is on the table base and not on the chuck table, and the chuck table is disposed at a position closer to a grinding unit including the grinding wheel than the dressing portion in the processing feed direction, the upper surface of the dressing portion is higher than the holding surface of the chuck table, When the dressing part is on the table base and not on the chuck table, and when the dressing part is disposed at a position closer to the grinding unit than the chuck table in the processing feed direction, the upper surface of the workpiece sucked and held by the holding surface of the chuck table is higher than the upper surface of the dressing part, A creep feed grinding method characterized in that, when the dressing portion is on the chuck table and the holding surface of the chuck table is positioned closer to the grinding unit than the dressing portion in the processing feed direction, the upper surface of the dressing portion is higher than the holding surface of the chuck table.

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