Grinding device

Abstract

To supply grinding water to a region to be ground in a circular arc shape more efficiently.SOLUTION: A grinding device comprises a grinding unit having a spindle having a longitudinal part arranged along a first direction, in which a grinding wheel is attached to a lower end part of the spindle; a chuck table having a holding surface arranged to face in the first direction, the chuck table which can move relatively with respect to the grinding unit along a second direction orthogonal to the first direction; and a grinding water supply unit that supplies grinding water from outside of the grinding wheel onto the holding surface. The grinding water supply unit has an enclosure having a longitudinal part arranged along a third direction which is orthogonal to both of the first direction and the second direction. A plurality of jet orifices are formed along the third direction in the enclosure. Grinding water is jetted through the plurality of jet orifices so that points on the holding surface on which grinding water falls form circular arc shapes corresponding to a portion of an outer periphery of the grinding wheel, in accordance with height positions of the jet orifices, sizes of the jet orifices or directions of end parts of flow paths contacting the jet orifices.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Small and lightweight electronic devices typified by mobile phones are equipped with semiconductor device chips having devices such as ICs (Integrated Circuits). The semiconductor device chip is manufactured by processing a workpiece including a disk-shaped single crystal substrate formed of a semiconductor material such as silicon.

[0003] For example, after forming devices such as ICs in each rectangular region on the front surface side partitioned by a plurality of division planned lines (streets) arranged in a grid pattern, the workpiece is cut along each street, and the workpiece is divided into semiconductor device chip units.

[0004] In recent years, for the purpose of miniaturization and weight reduction of semiconductor device chips, the workpiece may be thinned by polishing the back surface side of the workpiece before cutting. One method of grinding the workpiece is creep feed grinding.

[0005] In creep feed grinding, a grinding device is used. The grinding device includes a chuck table having a substantially flat holding surface. The chuck table is configured to be movable in a predetermined direction (grinding feed direction) orthogonal to the height direction of the grinding device.

[0006] Above the chuck table, a grinding unit having a cylindrical spindle is provided. The spindle is arranged along the height direction of the grinding device, and an annular grinding wheel having a diameter larger than the holding surface is attached to the lower end portion of the spindle via a disk-shaped mount.

[0007] The grinding wheel has an annular base. Multiple grinding wheels are arranged at approximately equal intervals along the circumferential direction of the base on one side of the base. When performing creep feed grinding, the spindle is operated to rotate the grinding wheel, and the lower surface of the grinding wheel is positioned at a height between the holding surface and the back surface of the workpiece.

[0008] Then, by moving the chuck table in a predetermined direction (i.e., grinding feed), the workpiece is moved together with the chuck table from the radially outer side of the grinding wheel to directly below the grinding wheel (see, for example, Patent Document 1).

[0009] Therefore, in creep feed grinding, the workpiece is ground on the outer circumference of multiple grinding wheels arranged in a ring (i.e., outer edge grinding). In outer edge grinding, grinding fluid such as pure water is supplied from a nozzle located on the radially outer side of the grinding wheel toward the contact area between the workpiece and the multiple grinding wheels.

[0010] For example, one nozzle with a circular opening or one slit nozzle with an elongated straight opening can be positioned radially outside the grinding wheel and higher than the area to be ground, thereby supplying grinding fluid to a point-like or linear area near the area to be ground.

[0011] However, in creep feed grinding, the area to be ground is arc-shaped, so supplying grinding fluid to a point-like area prevents the entire area from being ground. Furthermore, supplying grinding fluid to a linear area not only prevents the entire area from being ground, but also increases the amount of grinding fluid that is wasted without being used to remove the grinding heat and grinding debris generated during grinding. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2010-103192 [Overview of the project] [Problems that the invention aims to solve]

[0013] This invention has been made in view of the aforementioned problems, and aims to supply grinding fluid more efficiently to an arc-shaped area to be ground. [Means for solving the problem]

[0014] According to one aspect of the present invention, a grinding apparatus for grinding a workpiece comprises a grinding unit having a spindle whose longitudinal portion is arranged along a first direction, and a grinding wheel mounted on the lower end of the spindle for grinding the workpiece. , applicable A holding surface capable of holding a workpiece. and facing the first direction The system comprises a chuck table having a first direction and being movable relative to the grinding unit along a second direction perpendicular to the first direction, and a grinding water supply unit that supplies grinding water from the outside of the grinding wheel toward the holding surface, wherein the grinding water supply unit has a housing whose longitudinal portion is arranged along a third direction perpendicular to both the first and second directions, and the housing It includes a plane that is aligned with the first and third directions above the holding surface, and the one surface The grinding water supply unit is provided with a plurality of nozzles along the third direction, and the grinding water supply unit sprays the grinding water from the plurality of nozzles such that the landing point of the grinding water on the holding surface is in an arc shape corresponding to a part of the outer circumference of the grinding wheel, depending on the height position of each nozzle, the size of each nozzle, or the orientation of the end of the flow path in contact with each nozzle.

[0015] Preferably, the plurality of nozzles are arranged such that their height increases from the center to the ends of the housing in the third direction.

[0016] Preferably, the size of the plurality of nozzles decreases as you move from the center to the ends of the housing in the third direction.

[0017] Preferably, the angle of the end of the flow path in contact with the plurality of injection nozzles with respect to the second direction increases as you move from the center to the end in the third direction of the housing. [Effects of the Invention]

[0018] A grinding device according to one aspect of the present invention includes a grinding water supply unit that supplies grinding water toward the holding surface of a chuck table. The grinding water supply unit has a housing in which a long portion is arranged along a third direction orthogonal to a first direction corresponding to the longitudinal direction of a spindle and a second direction which is a relative movement direction between the chuck table and the grinding unit. A plurality of injection ports are provided in the housing along the third direction.

[0019] The grinding water supply unit injects the grinding water from the plurality of injection ports so that the landing point of the grinding water on the holding surface becomes an arc corresponding to a part of the outer periphery of the grinding wheel according to the height position of each injection port, the size of each injection port, or the orientation of the end of the flow path in contact with each injection port.

[0020] Thereby, the grinding water can be supplied in an arc shape having substantially the same curvature as the arc-shaped grinding region. In addition, compared with the case of supplying the grinding water to a linear region, the amount of grinding water discarded without being used for removing grinding heat and grinding chips can be reduced, so that the grinding water can be supplied efficiently.

Brief Description of the Drawings

[0021] [Figure 1] It is a perspective view showing an example of a grinding device. [Figure 2] It is a partial cross-sectional side view of a grinding device. [Figure 3] FIG. 3(A) is a view showing one side surface of the housing, FIG. 3(B) is a perspective view of the housing, FIG. 3(C) is a CC cross-sectional view of FIG. 3(A), FIG. 3(D) is a DD cross-sectional view of FIG. 3(A), and FIG. 3(E) is an EE cross-sectional view of FIG. 3(A). [Figure 4] It is a partial side view of a grinding device showing a holding process and a grinding process. [Figure 5] It is a top view of a chuck table etc. in a grinding process. [Figure 6]FIG. 6(A) is a view showing one side of the housing according to the second embodiment, FIG. 6(B) is a perspective view of the housing according to the second embodiment, FIG. 6(C) is a cross-sectional view taken along the line CC of FIG. 6(A), FIG. 6(D) is a cross-sectional view taken along the line DD of FIG. 6(A), and FIG. 6(E) is a cross-sectional view taken along the line EE of FIG. 6(A). [Figure 7] FIG. 7(A) is a view showing one side of the housing according to the third embodiment, FIG. 7(B) is a perspective view of the housing according to the third embodiment, FIG. 7(C) is a cross-sectional view taken along the line CC of FIG. 7(A), FIG. 7(D) is a cross-sectional view taken along the line DD of FIG. 7(A), and FIG. 7(E) is a cross-sectional view taken along the line EE of FIG. 7(A).

Embodiments for Carrying Out the Invention

[0022] An embodiment according to an aspect of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing an example of a grinding apparatus 2. In FIG. 1, a part of the components of the grinding apparatus 2 is shown in a simplified manner by functional blocks and lines.

[0023] Also, the X-axis direction (machining feed direction, second direction), Y-axis direction (left-right direction, third direction), and Z-axis direction (up-down direction, height direction, first direction) shown in FIG. 1 are directions orthogonal to each other. The components constituting the grinding apparatus 2 are supported or housed by a base 4.

[0024] On the upper surface side of the base 4, a rectangular opening 4a whose longitudinal direction is along the X-axis direction is formed. Behind the opening 4a, a rectangular parallelepiped support structure 6 whose longitudinal part is arranged along the Z-axis direction is provided.

[0025] In the opening 4a, a chuck table 8 for sucking and holding a workpiece 11 (see FIG. 4) is provided. The chuck table 8 has a disk-shaped frame body formed of non-porous ceramics. A disk-shaped recess is formed in the upper part of the frame body, and a disk-shaped porous plate 8c (see FIG. 5) formed of porous ceramics is fixed in this recess.

[0026] The upper surface of the frame and the upper surface of the porous plate 8c are substantially flush, forming a holding surface 8a that faces the Z-axis direction. The holding surface 8a is a flat surface substantially parallel to the XY plane. Negative pressure is supplied to the porous plate 8c from a suction source (not shown), such as a vacuum pump.

[0027] The workpiece 11 placed on the holding surface 8a is held in place by suction due to the negative pressure transmitted to the upper surface of the porous plate 8c. The workpiece 11 has a disc-shaped single-crystal substrate (i.e., a silicon wafer) made of a semiconductor material such as silicon.

[0028] However, there are no restrictions on the type, material, size, shape, structure, etc., of the workpiece 11. The workpiece 11 may have a disc-shaped substrate made of semiconductors other than silicon (GaAs, InP, GaN, SiC, etc.), glass, ceramics, resin, metal, etc.

[0029] Multiple division lines (not shown) are set in a grid pattern on the surface 11a of the workpiece 11. Devices such as ICs (Integrated Circuits), LEDs (Light Emitting Diodes), and MEMS (Micro Electro Mechanical Systems) (not shown) are formed in each rectangular region demarcated by the multiple division lines.

[0030] If a device is formed on the surface 11a side, the back surface 11b side of the workpiece 11 is ground. In this case, a resin protective tape is provided on the surface 11a of the workpiece 11 to protect the device. There are no restrictions on the type, quantity, shape, structure, size, or arrangement of the device. The workpiece 11 does not need to have a device formed on it.

[0031] As shown in Figure 1, the chuck table 8 is positioned above the approximately square table cover 10. On both sides of the table cover 10 in the X-axis direction, there are expandable bellows-shaped cover members 12 that have dustproof and waterproof functions.

[0032] Below the table cover 10 and cover member 12, an X-axis movement mechanism 14 is provided to move the chuck table 8 along the X-axis direction. In Figure 1, the approximate position of the X-axis movement mechanism 14 is indicated by an arrow, and in Figure 2, the details of the X-axis movement mechanism 14 are shown.

[0033] Figure 2 is a partial cross-sectional side view of the grinding apparatus 2 showing the X-axis movement mechanism 14, etc. Note that the table cover 10 and cover member 12 are omitted in Figure 2. The X-axis movement mechanism 14 has a pair of guide rails (not shown) fixed to the base 4. The pair of guide rails are fixed to the base 4 and arranged along the X-axis direction.

[0034] A flat, movable plate 16 is fixed to a pair of guide rails so as to be slidable along the X-axis direction. A nut portion 18 is provided on the underside of the movable plate 16. A screw shaft 20 is rotatably connected to the nut portion 18 via a plurality of balls (not shown).

[0035] A drive source 22, such as a stepping motor, is connected to one end of the screw shaft 20 to rotate the screw shaft 20. When the drive source 22 is operated, the movable plate 16 moves along the X-axis direction. The X-axis direction movement mechanism 14 is a ball screw type movement mechanism, but other mechanisms may be used as long as the chuck table 8 can be moved along the X-axis direction.

[0036] A support mechanism 24 is provided on the movable plate 16. The support mechanism 24 includes one fixed shaft and two movable shafts arranged at approximately equal intervals along the circumferential direction of the chuck table 8. In Figure 2, one fixed shaft and one movable shaft are shown.

[0037] As shown in Figure 2, the fixed axis is located on the rear side of the movable plate 16 (i.e., on the side of the support structure 6 and one side in the X-axis direction), and the movable axis is located on the front side of the movable plate 16 (the other side in the X-axis direction). The movable axis is extendable and retractable along the Z-axis direction.

[0038] The fixed and movable axes support the annular table base 26. The table base 26 has bearings (not shown) and rotatably supports the chuck table 8 via the bearings.

[0039] A through hole (not shown) is provided in the radial center of the table base 26. A cylindrical rotating shaft 8b is positioned in the through hole of the table base 26. The upper end of the rotating shaft 8b is fixed to the lower surface of the chuck table 8. A driven pulley (not shown) is provided at the lower end of the rotating shaft 8b.

[0040] A drive source (not shown), such as a motor, is fixed to the movable plate 16. A drive pulley (not shown) is provided on the output shaft of the drive source. An endless belt (not shown) is stretched over the drive pulley and the driven pulley. Power from the drive source is transmitted to the rotating shaft 8b via the endless belt or the like.

[0041] The grinding apparatus 2 of this embodiment can perform both creep-feed grinding, which grinds the workpiece 11 held by suction on the holding surface 8a without rotating the chuck table 8, and in-feed grinding, which grinds the workpiece 11 held by suction on the holding surface 8a while rotating the chuck table 8.

[0042] However, in this embodiment where creep feed grinding is performed, the rotating shaft 8b is not rotated. Also, the support mechanism 24 of this embodiment adjusts the inclination of the table base 26 to be approximately parallel to the XY plane, and therefore the rotating shaft 8b is positioned approximately parallel to the Z axis direction.

[0043] Now, returning to Figure 1, we will describe the other components of the grinding apparatus 2. A Z-axis movement mechanism 28 is provided on the front side of the support structure 6. The Z-axis movement mechanism 28 has a pair of guide rails 30 arranged along the Z-axis direction.

[0044] A movable plate 32 is slidably fixed to a pair of guide rails 30. A nut portion (not shown) is provided on the rear side of the movable plate 32. A screw shaft 34 is rotatably connected to this nut portion via a plurality of balls (not shown).

[0045] The screw shaft 34 is positioned along the Z-axis direction. A drive source 36, such as a stepping motor, is connected to the upper end of the screw shaft 34. When the drive source 36 is operated, the movable plate 32 moves along the Z-axis direction.

[0046] A cylindrical support member 38 is fixed to the front surface of the movable plate 32. The support member 38 supports a grinding unit 40 for grinding the workpiece 11 which is held in place by suction on the holding surface 8a.

[0047] The grinding unit 40 has a cylindrical spindle housing 42. The spindle housing 42 rotatably houses a cylindrical spindle 44 whose longitudinal portion is aligned along the Z-axis.

[0048] The lower end of the spindle 44 protrudes below the lower end of the spindle housing 42, and the center of a disc-shaped mount 46 made of metal or the like is fixed to this lower end. A rotational drive source, such as a servo motor, for rotating the spindle 44 is provided near the upper end of the spindle 44.

[0049] An annular grinding wheel 48 is fixed to the lower side of the mount 46 using fasteners such as bolts (not shown). In this way, the grinding wheel 48 is mounted to the lower end of the spindle 44 via the mount 46.

[0050] The grinding wheel 48 has an annular wheel base 48a made of a metal such as stainless steel or aluminum alloy. The outer diameter of the wheel base 48a is approximately the same as the outer diameter of the mount 46. Multiple grinding wheels 48b are arranged at approximately equal intervals on the lower surface of the wheel base 48a.

[0051] Each grinding wheel 48b contains abrasive grains made of diamond, cBN (cubic boron nitride), etc., and a bonding agent that fixes the abrasive grains. The bonding agent is, for example, a resin bond, a vitrified bond, a metal bond, etc.

[0052] A grinding water supply unit 50 (see Figures 4 and 5) that supplies grinding water 50a such as pure water is positioned in front of the grinding wheel 48 (i.e., in one direction outward from the grinding wheel 48) and above the holding surface 8a.

[0053] The grinding water supply unit 50 has a rectangular parallelepiped housing 52 whose longitudinal portion is arranged along the Y-axis. The housing 52 is made of a metal such as stainless steel, but may be made of other materials. As shown in Figure 2, one surface 52a located at the rear of the housing 52 is approximately parallel to the YZ plane, and the bottom surface 52b of the housing 52 is approximately parallel to the XY plane.

[0054] For example, one surface 52a is located approximately 5 cm away from the front end 40a of the grinding unit 40 along the X-axis direction, and the bottom surface 52b is located approximately 5 cm away from the height of the holding surface 8a along the Z-axis direction.

[0055] Here, the structure of the housing 52 will be explained with reference to Figures 3(A) to 3(E). Figure 3(A) is a view of one side 52a of the housing 52, and Figure 3(B) is a perspective view of the housing 52. Figure 3(C) is a cross-sectional view of CC of Figure 3(A), Figure 3(D) is a cross-sectional view of DD of Figure 3(A), and Figure 3(E) is a cross-sectional view of EE of Figure 3(A).

[0056] On the other front surface 52c of the housing 52, a pipe-shaped common channel 52d is provided along the extension direction of the longitudinal portion of the housing 52 (i.e., the Y-axis direction). The common channel 52d is made of the same material as the housing 52.

[0057] A conduit 54, consisting of a pipe, tube, etc., is connected to one end of the common channel 52d to supply grinding water 50a to the housing 52. For convenience, the conduit 54 is shown as a line in Figures 3(A) and 3(B).

[0058] Multiple nozzles 56 are provided on one surface 52a of the housing 52 at approximately equal intervals along the longitudinal direction of the housing 52. As shown in Figure 3(A), the multiple nozzles 56 are arranged in an arc shape on one surface 52a of the housing 52.

[0059] Each nozzle 56 in this embodiment is a circular opening formed on one surface 52a, and each has substantially the same shape and size. In this embodiment, 13 nozzles 56 are provided, but the number of nozzles 56 is not limited to 13.

[0060] Of the multiple injection nozzles 56 arranged in an arc shape, the injection nozzle 56 at the center 52e in the extension direction of the longitudinal part of the housing 52 is located at the lowest position, lower than the height position 52a1 of the center in the height direction of one surface 52a.

[0061] In contrast, as you move from the center 52e towards the side 52f of the housing 52 (i.e., one end in the extension direction of the longitudinal portion of the housing 52), the nozzle 56 gradually rises in height. The nozzle 56 closest to the side 52f is located at a higher position than the height position 52a1 of the center in the height direction of one surface 52a.

[0062] Similarly, as you move from the center 52e towards the side 52g of the housing 52 (i.e., the other end in the extension direction of the longitudinal part of the housing 52), the nozzle 56 gradually rises in height. The nozzle 56 closest to the side 52g is located at a higher position than the height position 52a1 of the center in the height direction of one surface 52a.

[0063] The curvature of the arcs of the multiple injection nozzles 56, which are arranged in an arc shape in this manner, is approximately the same as the curvature of a portion of the outer circumference of the ring defined by the multiple grinding wheels 48b. In other words, the arc defined by the multiple injection nozzles 56 corresponds to a portion of the outer circumference of the ring defined by the multiple grinding wheels 48b on the grinding wheel 48 (see Figure 5).

[0064] Furthermore, the distance 52h in the Y-axis direction from the nozzle 56 closest to the side surface 52f to the nozzle 56 closest to the other side surface 52g is longer than the diameter 8c1 of the porous plate 8c constituting the holding surface 8a, but shorter than the diameter of the frame (see Figure 5). In Figure 5, the porous plate 8c is shown with a dashed line.

[0065] As shown in Figures 3(C), 3(D), and 3(E), the nozzle 56 is connected to the tip of a flow channel 56a that extends approximately perpendicular to one surface 52a. The base end of the flow channel 56a is connected to a common flow channel 52d that extends approximately perpendicular to the other surface 52c of the housing 52.

[0066] As shown in Figure 3(C), the flow path 56a in the CC cross section is formed from the tip (i.e., the end on one side 52a) to the base (i.e., the end on the other side 52c) by bending appropriately according to the height position of the injection nozzle 56.

[0067] In contrast, as shown in Figure 3(D), in the DD cross-section, the injection nozzle 56 and the common flow path 52d are at approximately the same height, so the flow path 56a is straight from the tip to the base.

[0068] Furthermore, as shown in Figure 3(E), the flow path 56a in the EE cross section is formed from the tip to the base by bending appropriately according to the height position of the injection nozzle 56.

[0069] When grinding water 50a is supplied to the common channel 52d at a predetermined pressure and flow rate, the grinding water 50a is ejected from each nozzle 56. At this time, the landing point of the grinding water 50a differs depending on the height position of each nozzle 56.

[0070] Specifically, when grinding fluid 50a is supplied to the holding surface 8a, depending on the arrangement of the heights of each nozzle 56, the landing point of the grinding fluid 50a on the holding surface 8a will be in the shape of an arc corresponding to a part of the outer circumference of the grinding wheel 48 (the outer circumference of the ring defined by the multiple grinding wheels 48b) (see Figure 5).

[0071] Now, let's return to Figure 1 and describe the other components of the grinding apparatus 2. A liquid supply source 62 is connected to the conduit 54 via a valve 60 such as a solenoid valve. The liquid supply source 62 includes a tank (not shown) for storing pure water and a pump (not shown) for supplying pure water from the tank to the conduit 54.

[0072] The liquid supply source 62 is not a component of the grinding machine 2, but rather a liquid supply facility installed in the factory, or a mobile pure water supply device that purifies wastewater to produce reusable pure water. The liquid supply source 62 may supply pure water to one grinding machine 2, or it may supply pure water to multiple grinding machines 2.

[0073] The operation of the components of the grinding apparatus 2, such as the chuck table 8, the X-axis movement mechanism 14, the Z-axis movement mechanism 28, the grinding unit 40, and the valve 60, is controlled by the controller (control unit) 64.

[0074] The controller 64 is composed of a computer that includes, for example, a processor (processing unit) represented by a CPU (Central Processing Unit), main memory, and auxiliary memory.

[0075] Main memory includes DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), ROM (Read Only Memory), etc., while auxiliary memory includes flash memory, hard disk drives, solid state drives, etc.

[0076] The auxiliary storage device stores software, including a predetermined program. The controller 64's functions are realized by operating the processing unit and other components according to this software.

[0077] Next, creep feed grinding using the grinding device 2 will be described with reference to Figures 4 and 5. During creep feed grinding, as shown in Figure 4, the surface 11a side of the workpiece 11 is held by suction on the holding surface 8a, and the back surface 11b is exposed upwards (holding step). The holding step is performed on the front side of the opening 4a.

[0078] Next, the spindle 44 is rotated. The rotational speed of the spindle 44 is set to, for example, 1000 rpm or more and 3000 rpm or less. The grinding unit 40 is then lowered, and the lower surface of the grinding wheel 48b is positioned at a predetermined height between the holding surface 8a and the back surface 11b.

[0079] Then, the chuck table 8 and the grinding unit 40 are moved relative to each other along the X-axis direction to grind the back surface 11b of the workpiece 11 (grinding process). In this embodiment, as shown in Figure 4, with the position of the grinding unit 40 fixed, the chuck table 8 is moved backward by the X-axis movement mechanism 14.

[0080] The movement speed (processing feed rate) of the chuck table 8 is set to a predetermined range, for example, between 1 mm / s and 20 mm / s. Figure 4 is a side view of a part of the grinding apparatus 2, showing the holding process and the grinding process.

[0081] In the grinding process, the grinding water supply unit 50 supplies grinding water 50a onto the holding surface 8a while the grinding unit 40 grinds the workpiece 11. Figure 5 is a top view of the chuck table 8, etc., during the grinding process.

[0082] In the grinding process, the grinding area 11c of the workpiece 11 is arc-shaped. In this embodiment, grinding water 50a is sprayed onto the workpiece 11 from multiple nozzles 56 such that the landing point of the grinding water 50a is arc-shaped with approximately the same curvature as a part of the outer circumference of the ring defined by the multiple grinding wheels 48b, depending on the height position of the multiple nozzles 56.

[0083] Therefore, compared to supplying grinding water 50a in a linear region, the amount of grinding water 50a that is wasted without being used for grinding heat or removal of grinding chips can be reduced, thus enabling efficient supply of grinding water 50a.

[0084] Furthermore, as shown in Figure 5, grinding water 50a is supplied from multiple nozzles 56 such that the length of the arc-shaped landing point in the Y-axis direction is longer than the diameter 8c1 of the porous plate 8c. This allows grinding water 50a to be supplied to almost the entire area to be ground 11c during creep feed grinding, eliminating the situation where grinding water 50a is not supplied to the area to be ground 11c.

[0085] The chuck table 8 is fed into the grinding chamber inside the ring defined by the multiple grinding wheels 48b in the XY plane view. At the end of this first grinding pass, the grinding wheel 48 is raised. Then, the chuck table 8 is moved forward so that it is positioned outside the grinding wheel 48 in the XY plane.

[0086] Subsequently, if necessary, the grinding unit 40 is lowered again and a second grinding pass is performed. The number of passes is determined appropriately according to the material of the workpiece 11, the final thickness (i.e., the finished thickness), etc.

[0087] Incidentally, as a comparative example, it is also conceivable to set all the nozzles 56 at the same height position and form one surface 52a of the housing 52 into a curved surface such that, when viewed from above, the surface 52a has an arc shape with approximately the same curvature as the area to be ground 11c.

[0088] However, in this case, a part of the housing 52 may be located in the path of the grinding wheel 48 during the replacement of the grinding wheel 48. Normally, when replacing the grinding wheel 48, the grinding wheel 48 is first raised to approximately the same height as the housing 52.

[0089] Then, the operator removes the grinding wheel 48 from the mount 46 and moves the grinding wheel 48 in the Y-axis direction. Therefore, if one surface 52a is made up of a curved surface, there is a higher possibility that the grinding wheel 48 will come into contact with the housing 52.

[0090] In contrast, as in this embodiment, by making the housing 52 a rectangular parallelepiped and adjusting the height position of the spray nozzle 56, the grinding water 50a can be made to land in an arc shape, thereby reducing the possibility of contact or collision between the grinding wheel 48 and the housing 52 during the replacement of the grinding wheel 48.

[0091] In the first embodiment described above, the nozzle 56 is a circular opening formed on one surface 52a of the housing 52, but the nozzle 56 may be the tip of a pipe-shaped nozzle (not shown) that protrudes from the surface 52a.

[0092] Furthermore, the distance 52h from one end to the other in the Y-axis direction of the multiple nozzles 56 may be shorter than the diameter 8c1 of the porous plate 8c that constitutes the holding surface 8a. In this case, after adjusting the height position of each nozzle 56 on one surface 52a as described above, the orientation of each nozzle 56 in the XY plane should be set so that the grinding water 50a is sprayed in a fan shape when viewed from above the housing 52.

[0093] This allows the length of the housing 52 in the Y-axis direction to be shortened compared to the housing 52 of the first embodiment (see Figures 1 to 5). By making the housing 52 more compact in this way, the possibility of contact or collision with the housing 52 during operations such as replacing the grinding wheel 48 or performing maintenance on the grinding device 2 can be further reduced.

[0094] (Second Embodiment) Next, a second embodiment will be described with reference to Figure 6. Figure 6(A) is a view showing one side 52a of the housing 52 according to the second embodiment, and Figure 6(B) is a perspective view of the housing 52 according to the second embodiment.

[0095] Figure 6(C) is a cross-sectional view of section CC of Figure 6(A), Figure 6(D) is a cross-sectional view of section DD of Figure 6(A), and Figure 6(E) is a cross-sectional view of section EE of Figure 6(A). Elements identical to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0096] Multiple nozzles 66 are provided on one surface 52a of the housing 52 at approximately equal intervals along the longitudinal direction of the housing 52 (see Figure 6(A)). The multiple nozzles 66 are arranged in a straight line on one surface 52a of the housing 52 such that the center of each nozzle 66 is at the height position 52a1 of the center of the surface 52a in the height direction.

[0097] The nozzle 66 in this embodiment is a circular opening, similar to the nozzle 56 shown in Figure 3(A), but the size of the nozzle 66 differs depending on its position in the extension direction of the longitudinal portion of the housing 52. The diameter (size) of the nozzle 66 decreases in stages as you move from the center 52e to the side 52f of the housing 52 (i.e., one end of the longitudinal portion of the housing 52 in the extension direction).

[0098] Specifically, the diameter 68a of the nozzle 66 closest to the side 52f is smaller than the diameter 68b of the nozzle 66 located between the center 52e and the side 52f. Also, diameter 68b is smaller than the diameter 68c of the nozzle 66 at the center 52e.

[0099] Similarly, the diameter (size) of the nozzle 66 decreases in stages as you move from the center 52e to the side 52g of the housing 52 (i.e., the other end in the extension direction of the longitudinal part of the housing 52).

[0100] Specifically, the diameter 68a of the nozzle 66 closest to the side 52g is smaller than the diameter 68b of the nozzle 66 located approximately midway between the center 52e and the side 52g. Also, diameter 68b is smaller than the diameter 68c of the nozzle 66 at the center 52e.

[0101] As shown in Figures 6(C), 6(D), and 6(E), the nozzle 66 is connected to the tip of a flow channel 66a that extends approximately perpendicular to one surface 52a. The base end of the flow channel 66a is connected to a common flow channel 52d that is approximately perpendicular to the other surface 52c.

[0102] As shown in Figures 6(C) and 6(D), the diameters 68a and 68b of the nozzle 66 are smaller than the diameter of the base end of the flow path 66a (i.e., the end on the other side 52c), so the flow path 66a becomes a tapered cylindrical shape as it progresses from the base end to the tip.

[0103] In contrast, as shown in Figure 6(E), the diameter 68c of the injection nozzle 66 in the central part 52e is approximately the same as the diameter of the base end of the flow path 66a, so the flow path 66a is cylindrical with approximately the same diameter from the base end to the tip.

[0104] The landing point of the grinding water 50a differs depending on the diameter of each nozzle 66. When grinding water 50a is supplied to the common flow path 52d at a predetermined pressure and flow rate, the flow velocity increases as the diameter of the nozzle 56 decreases, so the grinding water 50a lands further away in the X-axis direction.

[0105] The diameter of each nozzle 66 is adjusted so that the landing point of the grinding water 50a on the holding surface 8a is arc-shaped. In this embodiment as well, the grinding water 50a can be supplied in an arc shape with approximately the same curvature as the arc-shaped area to be ground 11c.

[0106] In addition, compared to supplying grinding water 50a to a linear region, the grinding water 50a can be supplied more efficiently. Furthermore, the grinding water 50a can be supplied to almost the entire area to be ground 11c.

[0107] (Third Embodiment) Next, a third embodiment will be described with reference to Figure 7. Figure 7(A) is a view showing one side 52a of the housing 52 according to the third embodiment, and Figure 7(B) is a perspective view of the housing 52 according to the third embodiment. In both Figure 7(A) and Figure 7(B), the conduit 54 is shown as a straight line.

[0108] Figure 7(C) is a cross-sectional view of section CC of Figure 7(A), Figure 7(D) is a cross-sectional view of section DD of Figure 7(A), and Figure 7(E) is a cross-sectional view of section EE of Figure 7(A). Elements identical to those in the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0109] Multiple nozzles 76 are provided on one surface 52a of the housing 52 at approximately equal intervals along the longitudinal direction of the housing 52 (see Figure 7(A)). The multiple nozzles 76 are arranged in a straight line on one surface 52a of the housing 52 such that the center of each nozzle 66 is located slightly above the height position 52a1 of the center of the surface 52a in the height direction.

[0110] The nozzle 76 in this embodiment is a circular opening, similar to the nozzle 56 shown in Figure 3(A), and each has approximately the same opening area. However, the orientation 76b of the tip (end) of the flow path 76a that contacts the nozzle 76 (i.e., the direction of the grinding water 50a injection) differs depending on the position in the extension direction of the longitudinal portion of the housing 52.

[0111] Specifically, the angle between the orientation 76b of the tip of the flow path 76a in contact with the nozzle 76 and the normal 52a2 (a straight line parallel to the X-axis) of one surface 52a increases in stages as you move from the center 52e to the side surface 52f or side surface 52g of the housing 52.

[0112] Therefore, the angle of the grinding water 50a ejected from the nozzle 76 with respect to the X-axis direction increases as it moves from the center 52e to the side 52f of the housing 52 (i.e., one end in the extension direction of the longitudinal part of the housing 52).

[0113] As shown in Figures 7(C) and 7(D), the angle α between the orientation 76b of the tip of the channel 76a closest to the side surface 52f and the normal 52a2 is greater than the angle β between the orientation 76b of the tip of the channel 76a located between the center 52e and the side surface 52f and the normal 52a2. The angle α is, for example, 45 degrees, but is not limited to 45 degrees.

[0114] Furthermore, as shown in Figures 7(D) and 7(E), angle β is greater than the angle γ formed by the orientation 76b of the tip of the flow channel 76a in the central part 52e and the normal 52a2. Angle γ is, for example, 30 degrees, but is not limited to 30 degrees.

[0115] Similarly, the angle between the orientation 76b of the tip of the flow path 76a and the normal 52a2 increases as you move from the center 52e to the side 52g of the housing 52 (i.e., the other end in the extension direction of the longitudinal part of the housing 52).

[0116] Similar to Figures 7(C) and 7(D), the angle α between the orientation 76b of the tip of the channel 76a closest to the side surface 52g and the normal 52a2 is greater than the angle β between the orientation 76b of the tip of the channel 76a located approximately midway between the central part 52e and the side surface 52g and the normal 52a2.

[0117] As shown in Figures 7(C) to 7(E), each nozzle 76 is located at approximately the same height as the common flow path 52d, however, the height of each nozzle 76 and the height of the common flow path 52d may be different. The height of each nozzle 76 may be located above the height of the common flow path 52d.

[0118] As shown in Figure 7(C), the flow path 76a is recessed between one surface 52a and the other surface 52c, so that the orientation 76b of the tip of the flow path 76a forms an angle α with respect to the X-axis direction.

[0119] The channel 76a shown in Figure 7(D) is shallower than that in Figure 7(C) between one surface 52a and the other surface 52c, such that the orientation 76b of the tip of the channel 76a forms an angle β with respect to the X-axis direction.

[0120] Furthermore, the channel 76a shown in Figure 7(E) is shallower than the channel 76a shown in Figure 7(D) between one surface 52a and the other surface 52c, such that the orientation 76b of the tip of the channel 76a forms an angle γ with respect to the X-axis.

[0121] When grinding water 50a is supplied to the common channel 52d at a predetermined pressure and flow rate, the landing point of the grinding water 50a differs depending on the orientation 76b of the leading edge of the channel 76a. The larger the angle between the orientation 76b of the leading edge of the channel 76a and the normal 52a2 (X-axis direction), the further away the grinding water 50a lands.

[0122] In other words, the grinding water 50a sprayed at an angle α lands furthest away, and the grinding water 50a sprayed at an angle γ lands closest. The orientation 76b of the tip of each flow path 76a is adjusted so that the landing point of the grinding water 50a on the holding surface 8a is in an arc shape.

[0123] In this embodiment as well, grinding water 50a can be supplied in an arc shape with approximately the same curvature as the arc-shaped area to be ground 11c. In addition, compared to supplying grinding water 50a to a linear area, the grinding water 50a can be supplied more efficiently. Furthermore, grinding water 50a can be supplied to almost the entire area to be ground 11c.

[0124] Furthermore, the structures, methods, etc., of the embodiments described above can be modified as appropriate without departing from the scope of the object of the present invention. For example, in each of the embodiments described above, the chuck table 8 is moved along the X-axis direction by the X-axis direction movement mechanism 14, but instead of the chuck table 8, the grinding unit 40 may be moved along the X-axis direction.

[0125] Alternatively, if the chuck table 8 and the grinding unit 40 can be moved relative to each other along the X-axis, both the chuck table 8 and the grinding unit 40 may be moved along the X-axis.

[0126] Furthermore, although the above embodiments were described on the premise of creep-feed grinding, the grinding water supply unit 50 described in the first to third embodiments can also be applied to infeed grinding using an external blade grinding method.

[0127] In infeed grinding, a disc-shaped chuck table 8 is used, which has a conical holding surface 8a whose central part protrudes by approximately 20 μm compared to the outer circumference. In addition, the rotation axis 8b of the chuck table 8 is slightly tilted so that a part of the holding surface 8a is approximately parallel to the XY plane.

[0128] During infeed grinding, if the rotation direction of the chuck table 8 and the rotation direction of the grinding wheel 48 are opposite in an XY plan view, the back surface 11b of the workpiece 11 held by the holding surface 8a can be ground with the outer blades of the grinding wheel 48 (i.e., the outer circumference of the multiple grinding wheels 48b). [Explanation of Symbols]

[0129] 2: Grinding device, 4: Base, 4a: Opening, 6: Support structure 8: Chuck table, 8a: Holding surface, 8b: Rotating shaft, 8c: Porous plate, 8c1: Diameter 10: Table cover, 12: Cover component 11: Workpiece, 11a: Front surface, 11b: Back surface, 11c: Area to be ground 14: X-axis movement mechanism, 16: Moving plate, 18: Nut section, 20: Screw shaft, 22: Drive source 24: Support mechanism, 26: Table base 28: Z-axis movement mechanism, 30: Guide rail, 32: Moving plate, 34: Screw shaft 36: Drive source, 38: Support member, 40: Grinding unit, 40a: Front end 42: Spindle housing, 44: Spindle 46: Mount, 48: Grinding wheel, 48a: Wheel base, 48b: Grinding wheel 50: Grinding water supply unit, 50a: Grinding water 52: Enclosure, 52a: One side, 52a1: Height position, 52a2: Normal vector 52b: bottom surface, 52c: other surface, 52d: common channel 52e: Center, 52f, 52g: Side, 52h: Distance, 54: Conduit 56: Injection nozzle, 56a: Flow path 60: Valve, 62: Liquid supply source, 64: Controller 66: nozzle, 66a: flow path, 68a, 68b, 68c: diameter 76: nozzle, 76a: flow path, 76b: direction of tip (direction of end) α, β, γ: angles

Claims

1. A grinding device for grinding a workpiece, A grinding unit having a spindle with a longitudinal portion arranged along a first direction, and grinding the workpiece with a grinding wheel attached to the lower end of the spindle, A chuck table having a holding surface capable of holding the workpiece and facing the first direction, and movable relative to the grinding unit along a second direction perpendicular to the first direction, The system includes a grinding water supply unit that supplies grinding water from the outside of the grinding wheel toward the holding surface, The grinding water supply unit has a housing whose longitudinal portion is arranged along a third direction perpendicular to both the first and second directions, and the housing includes one surface which is a plane along the first and third directions above the holding surface, and this surface is provided with a plurality of spray nozzles along the third direction. The grinding water supply unit is characterized by spraying the grinding water from a plurality of nozzles such that the landing point of the grinding water on the holding surface is in an arc shape corresponding to a part of the outer circumference of the grinding wheel, depending on the height position of each nozzle, the size of each nozzle, or the orientation of the end of the flow path in contact with each nozzle.

2. The grinding apparatus according to claim 1, characterized in that the plurality of nozzles are arranged such that their height increases from the center to the ends in the third direction of the housing.

3. The grinding apparatus according to claim 1, characterized in that the size of the plurality of injection nozzles decreases as you move from the center to the ends in the third direction of the housing.

4. The grinding apparatus according to claim 1, characterized in that the angle of the end of the flow path in contact with the plurality of injection nozzles with respect to the second direction increases as you move from the center to the end in the third direction of the housing.

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