Grinding device

Abstract

To effectively perform cooling of a part to be ground of a wafer and removal of grinding chips, while suppressing a rotation load of a grinding stone to reduce electric power consumption.SOLUTION: A grinding device 1 is provided with: a chuck table 10 that rotates while holding a wafer W; a grinding unit 30 that grinds the wafer W by rotating a grinding stone 35b with a rotation center of the wafer W as a shaft, while passing the grinding stone on the rotation center of the wafer W held on the chuck table 10; and a nozzle 53 that supplies grinding water to an upper surface of the wafer W inside the grinding stone 35b, which grinds the wafer W when the wafer W rotates from the inside of the grinding stone 35b toward the outside thereof. The nozzle 53 is arranged along a radial direction of the grinding stone 35b, inside the grinding stone 35b. A jet port 53a which jets grinding water toward an inner surface of the grinding stone 35b is formed at a tip of the nozzle 53. A plurality of supply ports 53b which supply grinding water toward an upper surface of the wafer W are formed along the longitudinal direction on a lower surface of a tip part of the nozzle 53.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a grinding apparatus that grinds a wafer held on a holding surface of a chuck table with an annular grinding wheel. [Background technology]

[0002] In the manufacturing process of semiconductor devices such as ICs and LSIs used in electronic devices, the backside of the wafer is ground to thin the wafer to a predetermined thickness in order to reduce the size and weight of the semiconductor devices. In particular, in recent years, there has been a demand for thinner semiconductor devices to meet the demand for thinner and more compact electronic devices.

[0003] A grinding machine for grinding wafers rotates a wafer held on the holding surface of a chuck table while rotating multiple grinding wheels arranged in a ring shape in a grinding unit, bringing them into contact with the top surface (back surface) of the wafer to grind the top surface of the wafer. However, the contact area between the grinding wheels and the wafer (grinding area) becomes overheated due to heat generated by friction, and grinding debris is generated by grinding the wafer. For this reason, grinding water is supplied to the contact area between the grinding wheels and the wafer (grinding area) to cool the contact area with the grinding water and to wash away grinding debris generated by grinding the wafer with the grinding water.

[0004] However, because both the wafer and the grinding wheel rotate at high speed, the grinding water supplied to the contact area (grinding area) between the grinding wheel and the wafer is scattered around by centrifugal force, resulting in the problem that the grinding water is not sufficiently supplied to the contact area (grinding area) between the grinding wheel and the wafer.

[0005] Therefore, Patent Documents 1 and 2 propose providing an inner grinding water jetting means and an outer grinding water jetting means for jetting grinding water onto the inner and outer peripheral surfaces of the grinding wheel, respectively. Also, Patent Document 3 proposes a grinding device in which grinding water is jetted from a nozzle in a straight line toward the center of the wafer, along the upper surface of the wafer from the outer periphery toward the center of the rotating wafer, and centrifugal force is applied to the grinding water by the rotation of the chuck table to direct the grinding water along the upper surface of the wafer toward the outer periphery of the wafer, thereby moving the grinding water to the processing point where the grinding wheel contacts the wafer, thereby supplying the grinding water to the entire area of ​​the processing point. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-212555 [Patent Document 2] Japanese Patent Publication No. 2023-047614 [Patent Document 3] Japanese Patent Application Publication No. 2023-161339 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the grinding devices proposed in Patent Documents 1 and 2 have the problem that the grinding water sprayed toward the inner and outer periphery of the grinding wheel interferes with the rotation of the grinding wheel, resulting in increased power consumption by the motor that rotates the grinding wheel.

[0008] Furthermore, the grinding device proposed in Patent Document 3 has a problem in that grinding debris is not sufficiently removed from the grinding wheel, causing deep scratches on the wafer due to the grinding debris.

[0009] The present invention has been made in consideration of the above problems, and its object is to provide a grinding device that can effectively cool the portion of the wafer being ground and remove grinding debris while keeping the rotational load of the grinding wheel low and reducing power consumption. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides a grinding device comprising a chuck table that holds a wafer by a holding surface and rotates around the center of the holding surface as an axis, a grinding unit that rotates an annular grinding wheel around the center of the wafer held on the chuck table as the wheel passes through the center of rotation of the wafer held on the chuck table to grind the wafer, and a nozzle that supplies grinding water to the upper surface of the wafer inside the grinding wheel, wherein the grinding device grinds the wafer as the wafer rotates from the inside to the outside of the grinding wheel, and the nozzle is arranged inside the grinding wheel along the radial direction of the grinding wheel, and an injection port is formed at the tip of the nozzle for injecting grinding water toward the inner surface of the grinding wheel, and a plurality of supply ports are formed along the longitudinal direction at the underside of the tip of the nozzle for supplying grinding water toward the upper surface of the wafer. [Effects of the Invention]

[0011] According to the present invention, a portion of the grinding water supplied from a grinding water supply source to a nozzle arranged inside the grinding wheel along the radial direction of the grinding wheel is supplied toward the upper surface of the wafer from multiple supply ports opening on the lower surface of the nozzle, and the grinding water supplied to the upper surface of the wafer is supplied to the contact area (grinding area) between the wafer and the grinding wheel as the wafer rotates, and only the remaining grinding water is sprayed toward the inside of the grinding wheel from the spray port opening on the tip surface of the nozzle, thereby reducing the load on the spindle motor that rotates the grinding wheel and thereby reducing power consumption.

[0012] In addition, grinding water is supplied toward the top surface of the wafer from multiple supply ports opening on the bottom surface of the nozzle, and the grinding water is sprayed toward the center of the wafer from a spray port opening on the tip surface of the nozzle, so that the entire top surface of the wafer, which is the surface to be ground, can be uniformly cooled by the grinding water, and grinding debris can be effectively washed away and removed from the wafer by the grinding water. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view of a grinding device according to a first embodiment of the present invention. [Figure 2] 1 is a perspective view of a nozzle and a lifting mechanism provided in a grinding device according to a first embodiment of the present invention. FIG. [Figure 3] 1 is a cutaway side view of a main part of a grinding device according to a first embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged detailed view of part A in FIG. 3. [Figure 5] 1 is a plan view showing the positional relationship between a wafer being ground, a grinding wheel, and a nozzle in a grinding device according to a first embodiment of the present invention. FIG. [Figure 6] FIG. 5 is a perspective view of a grinding device according to a second embodiment of the present invention. [Figure 7] FIG. 6 is a vertical cross-sectional view of a grinding unit of a grinding device according to a second embodiment of the present invention. [Figure 8] FIG. 8 is an enlarged detailed view of part B in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] First Embodiment First, the configuration of a grinding device 1 according to a first embodiment of the present invention will be described.

[0016] [Grinding equipment configuration] The grinding apparatus 1 shown in Fig. 1 grinds a disk-shaped wafer W, which is a workpiece, and includes the following components: In the following description, the directions of the arrows shown in Fig. 1 are the X-axis direction (left-right direction), the Y-axis direction (front-back direction), and the Z-axis direction (up-down direction), respectively.

[0017] That is, the grinding apparatus 1 has as its main components a chuck table 10 which holds the wafer W on a circular holding surface on its upper surface and rotates around the center of the holding surface as an axis; a horizontal movement mechanism 20 which moves the chuck table 10 in the Y-axis direction (front-to-back direction); a grinding unit 30 which grinds the wafer W held by suction on the holding surface of the chuck table 10; a vertical movement mechanism 40 which moves the grinding unit 30 up and down in a direction perpendicular to the holding surface of the chuck table 10 (Z-axis direction); and a grinding water supply means 50 which supplies grinding water to the contact area (grinding area) between the grinding wheel 35b of the grinding unit 30 and the wafer W.

[0018] 1, a plurality of devices (not shown) are formed on the surface facing downward, and these devices are protected by a protective tape T (see FIG. 3) attached to the surface of the wafer W. As shown in FIG. 3, the front surface (the lower surface in FIG. 3) of the wafer W is suction-held on the holding surface of the chuck table 10 via the protective tape T, and the back surface (the upper surface in FIG. 3) of the wafer W is ground by the grinding wheel 35b of the grinding unit 30 while receiving a supply of grinding water from the grinding water supply means 50.

[0019] Next, the configurations of the chuck table 10, horizontal movement mechanism 20, grinding unit 30, vertical movement mechanism 40, and grinding water supply means 50, which are the main components of the grinding device 1, will be described.

[0020] (Chuck table) The chuck table 10 is a disk-shaped member that is rotated by the rotation mechanism 2 around the center of the holding surface as an axis. As shown in FIG. 3, a disk-shaped porous member 11 made of porous ceramic or the like is mounted in the center of the top of the chuck table 10. The upper surface of the porous member 11 forms the holding surface that suction-holds the wafer W, and as shown in FIG. 3, the porous member 11 is selectively connected to a suction source 13 such as a vacuum pump or an ejector via a communication passage 10a formed in the center of the chuck table 10 and a pipe 12 connected to the communication passage 10a. The holding surface of the chuck table 10 is formed in a cone shape with the center of rotation as its apex.

[0021] As shown in FIG. 1, the chuck table 10 has a chuck rotation shaft 14 extending vertically downward from the center thereof. The chuck table 10 is rotatably supported by a ring-plate-shaped support flange 15 via a bearing (not shown). The chuck table 10 is driven to rotate at a predetermined speed around the vertical axis of the chuck rotation shaft 14 by the rotation mechanism 2.

[0022] Here, the rotation mechanism 2 includes an electric motor 4 as a rotational drive source, which is attached by a stay 3 to the side of a block-shaped slider 21 provided on a horizontal movement mechanism 20 (described later). A small-diameter drive pulley 5 is connected to an output shaft (not shown) extending upward from the electric motor 4, and a large-diameter driven pulley 6 is connected to the chuck rotation shaft 14. An endless timing belt 7 is wound around the drive pulley 5 and the driven pulley 6. An encoder 8 is attached to the electric motor 4 to detect the rotation speed of the electric motor 4, etc.

[0023] 1, the grinding apparatus 1 according to this embodiment includes a rectangular box-shaped base 100 that is long in the Y-axis direction (front-rear direction), and the chuck table 10 faces a rectangular opening 100a that is long in the Y-axis direction and opens in the top surface of the base 100. The periphery of the chuck table 10 at the opening 100a in the top surface of the base 100 is covered by a rectangular plate-shaped cover 16, and the front and rear (-Y direction and +Y direction) portions of the cover 16 at the opening 100a are covered by bellows-shaped extendable covers 17 that move and extend together with the cover 16. Therefore, regardless of the position of the chuck table 10 on the Y-axis, the opening 100a is always closed by the cover 16 and the extendable cover 17, and foreign matter cannot enter the base 100 through the opening 100a.

[0024] (Horizontal movement mechanism) The horizontal movement mechanism 20 is a mechanism for moving the chuck table 10 in the horizontal direction (Y-axis direction) relative to the holding surface, and is disposed on a rectangular block-shaped internal base 101 housed inside the base 100, as shown in Fig. 1. The horizontal movement mechanism 20 includes a block-shaped slider 21, which is slidable in the Y-axis direction along a pair of left and right guide rails 22 disposed parallel to each other along the Y-axis direction (front-rear direction). Therefore, the chuck table 10 supported by the slider 21 and the rotation mechanism 2 including the electric motor 4 and the like are movable along the Y-axis direction together with the slider 21.

[0025] A rotatable ball screw 23 extending along the Y-axis direction (front-rear direction) is disposed between a pair of left and right guide rails 22 on the internal base 101, and one end of the ball screw 23 in the Y-axis direction (the left end in FIG. 1) is connected to a reversible electric motor 24, which serves as a drive source. The other end of the ball screw 23 in the Y-axis direction (the right end in FIG. 1) is rotatably supported by a bearing 25 erected on the internal base 101. A nut member (not shown) protruding downward from the slider 21 is threadedly engaged with the ball screw 23.

[0026] Therefore, when the electric motor 24 is started to rotate the ball screw 23 forward or backward, a nut member (not shown) that is threaded onto the ball screw 23 slides in the Y-axis direction (front-back direction) along the ball screw 23 together with the slider 21, and the chuck table 10 also moves integrally along the Y-axis direction together with the slider 21. As a result, the wafer W that is suction-held on the holding surface of the chuck table 10 also moves along the Y-axis direction.

[0027] (Grinding unit) The grinding unit 30 includes a spindle motor 32 fixed to a holder 31, a vertical spindle 33 that is rotated by the spindle motor 32, a disk-shaped mount 34 attached to the lower end of the spindle 33, and a grinding wheel 35 that is detachably attached to the underside of the mount 34. Here, the grinding wheel 35 is composed of a disk-shaped base 35a and a grinding stone 35b that is attached in an annular shape to the underside of the base 35a.

[0028] (Vertical movement mechanism) The vertical movement mechanism 40 moves the grinding unit 30 up and down in the direction perpendicular to the holding surface of the chuck table 10 (Z-axis direction), and is disposed on the −Y-axis direction end face (front face) of a rectangular box-shaped column 110 that is erected vertically on the +Y-axis direction end face (rear end face) of the upper surface of the base 100, as shown in Fig. 1. The vertical movement mechanism 40 moves a rectangular plate-shaped lift plate 41 attached to the back face of the holder 31 up and down in the Z-axis direction together with the holder 31 and the spindle 33 and grinding wheel 35 held by the holder 31 along a pair of left and right guide rails 42. The pair of left and right guide rails 42 are disposed perpendicular to the front face of the column 110 and parallel to each other.

[0029] A rotatable ball screw 43 is provided between the pair of left and right guide rails 42, standing vertically along the Z-axis direction (up and down direction), and the upper end of the ball screw 43 is connected to a reversible electric motor 44, which serves as a drive source. The electric motor 44 is attached in a vertical position via a rectangular plate-shaped bracket 45 attached to the upper surface of the column 110. The lower end of the ball screw 43 is rotatably supported by the column 110, and a nut member (not shown) that protrudes horizontally from the back surface of the lifting plate 41 toward the rear (+Y-axis direction) is threadedly engaged with the ball screw 43.

[0030] Therefore, when the electric motor 44 is started to rotate the ball screw 43 forward and backward, the lifting plate 41, which is fitted with a nut member (not shown) that threads onto the ball screw 43, moves up and down in the Z-axis direction along the guide rail 42 together with the grinding unit 30.

[0031] (Grinding water supply means) As shown in Fig. 3, the grinding water supply means 50 includes a grinding water supply source 51 and a nozzle 53 that sprays the grinding water supplied from the grinding water supply source 51 through a pipe 52 toward the inner surface of the grinding wheel 35b and the upper surface of the wafer W. Here, as shown in Fig. 3, the nozzle 53 is arranged horizontally inside the grinding wheel 35b along the radial direction of the grinding wheel 35b (the left-right direction in Fig. 3). Note that pure water is preferably used as the grinding water.

[0032] More specifically, as shown in FIG. 2, nozzle 53 is a horizontally arranged rectangular plate-shaped member, and at the top and bottom of the interior thereof, as shown in FIGS. 3 and 4, two circular hole-shaped supply passages 53A and 53B are formed parallel to each other and horizontally along the longitudinal direction, and one end of each supply passage 53A and 53B is connected to pipe 52 by a plug 54.

[0033] Of the two supply paths 53A, 53B formed horizontally in the vertical direction inside the nozzle 53, one injection port 53a that injects grinding water toward the inner surface of the grinding wheel 35b opens obliquely downward at the tip of the upper supply path 53A, as shown in Fig. 4, and the tip (left end in Figs. 3 and 4) of the lower supply path 53B opens as multiple supply ports 53b in the lower surface of the nozzle 53. Here, the multiple supply ports 53b (seven in the illustrated example) open at appropriate intervals along the longitudinal direction (left-right direction in Fig. 4) in the center of the width direction of the lower surface of the nozzle 53, and as described below, grinding water is supplied from each supply port 53b toward the upper surface of the wafer W. The number of supply ports 53b does not need to be seven and can be any number as long as it is plural.

[0034] 3, a pipe 52 extending from a grinding water supply source 51 that supplies grinding water to the nozzle 53 penetrates a side plate 61A of the machining chamber S and is introduced into the interior of the machining chamber S, and its end branches into two that are connected to upper and lower plugs 54, respectively. A partition joint 62 is attached to the portion of the side plate 61A of the machining chamber S where the pipe 52 penetrates, and the pipe 52 penetrates this partition joint 62 and is introduced into the machining chamber S.

[0035] 3, the nozzle 53 is supported horizontally in an overhanging state by having its rear end (base end) attached to the upper end of a plate 55C that stands vertically at the tip of a plate-like arm 55B that extends horizontally from the upper end of a vertical movable plate 55A that penetrates the bottom plate 61B of the processing chamber S. The nozzle 53, supported horizontally in this manner, can be raised and lowered in the Z-axis direction by an elevating mechanism 70. A seal member 63 is attached to the portion where the movable plate 55A penetrates the bottom plate 61B of the processing chamber S.

[0036] 2, the lifting mechanism 70 is composed of a pair of guide rails 72 attached parallel to each other vertically to a rectangular support plate 71 that stands upright, a slider 73 that moves up and down along the guide rails 72, a ball screw 74 arranged vertically between the pair of guide rails 72, and an electric motor 75 that rotates the ball screw 74 forward and backward. The lower end of a movable plate 55A that supports the nozzle 53 is attached to the slider 73, and a nut member (not shown) into which the ball screw 74 is threaded is attached to the back surface of the slider 73. Therefore, when the electric motor 75 is started to rotate the ball screw 74 forward and backward, the slider 73, to which the nut member (not shown) into which the ball screw 74 is threaded, moves up and down together with the movable plate 55A and the nozzle 53, and the nozzle 53 can be raised and lowered in the Z-axis direction.

[0037] [Function of grinding equipment] Next, the operation of the grinding apparatus 1 configured as above, that is, the grinding process of the wafer W by the grinding apparatus 1 will be described.

[0038] In the grinding apparatus 1 according to this embodiment, when grinding a wafer W, the wafer W is placed on the holding surface of the chuck table 10 with the protective tape T facing down, as shown in Fig. 3. Then, the porous member 11 of the chuck table 10 is connected to the suction source 13 via the communication passage 10a and the piping 12, and the porous member 11 is suctioned by the suction source 13. This generates a negative pressure in the porous member 11, and the wafer W is attracted by this negative pressure and held by suction on the holding surface of the chuck table 10 (the upper surface of the porous member 11).

[0039] As described above, when the wafer W is suction-held on the holding surface of the chuck table 10, the upper surface of the wafer W becomes conical following the shape of the holding surface, and the horizontal movement mechanism 20 shown in FIG. 1 is driven to move the chuck table 10 in the +Y-axis direction (rearward), thereby positioning the wafer W suction-held on the chuck table 10 below the grinding wheel 35 of the grinding unit 30. That is, when the electric motor 24 is started to rotate the ball screw 23, the slider 21, to which a nut member (not shown) threadedly engaged with the ball screw 23 is attached, moves in the +Y-axis direction along the pair of left and right guide rails 22 together with the chuck table 10, etc., so that the wafer W held on the holding surface of the chuck table 10 is positioned below the grinding wheel 35 of the grinding unit 30. At this time, the horizontal positions (Y-axis positions) of the grinding wheel 35b and the grinding wheel 35b are adjusted so that the lower surface (circumscribed circle) of the grinding wheel 35b passes through the center of the wafer W, as shown in FIG. 5.

[0040] 1 is driven to rotate the chuck table 10, causing the wafer W suction-held on the holding surface of the chuck table 10 to rotate at a predetermined rotational speed (e.g., 300 min-1) in the direction of the arrow (counterclockwise) shown in Fig. 5, and the spindle motor 32 of the grinding unit 30 is started to rotate the grinding wheel 35 (grinding stone 35b) in the direction of the arrow (counterclockwise) in Fig. 5 at a predetermined rotational speed (e.g., 2000 min-1). That is, when the electric motor 4 of the rotation mechanism 2 is started, its rotation is reduced and transmitted to the chuck rotation shaft 14 via the drive pulley 5, the timing belt 7, and the driven pulley 6, so that the chuck table 10 and the wafer W suction-held thereon are rotated together with the chuck rotation shaft 14 at a predetermined speed.

[0041] As described above, while the wafer W and the grinding wheel 35 (grinding stone 35b) are rotating, the vertical movement mechanism 40 is driven to lower the grinding wheel 35 in the −Z-axis direction. That is, when the electric motor 44 is started and the ball screw 43 rotates, the lifting plate 41, to which a nut member (not shown) that threads onto the ball screw 43 is attached, is lowered in the −Z-axis direction together with the grinding wheel 35 and other components. As a result, the lower surface (machined surface) of the grinding stone 35b of the grinding wheel 35 comes into contact with the grinding region shown in FIG. 5 on the upper surface (back surface) of the wafer W. When the grinding wheel 35 further descends in the −Z-axis direction from the state in which the lower surface of the grinding stone 35b is in contact with the upper surface of the wafer W, the upper surface (back surface) of the wafer W is ground by the grinding stone 35b of the grinding wheel 35 as the wafer W rotates from the inside to the outside of the grinding stone 35b.

[0042] As described above, during the grinding process in which the wafer is ground by the grinding wheel 35b, grinding water is supplied from the grinding water supply source 51 of the grinding water supply means 50 to the nozzle 53 through the pipe 52, and the grinding water supplied to the nozzle 53 is sprayed toward the inside of the grinding wheel 35b from the nozzle 53a at the tip of one (upper) supply path 53A of the nozzle 53, as shown in Figures 3 and 4. The grinding water sprayed from the nozzle 53a of the nozzle 53 toward the center of the wafer W inside the grinding wheel 35b is subjected to centrifugal force by the rotation of the grinding wheel 35b, as shown by the arrow in Figure 5, and is discharged outside the grinding wheel 35b from the gap between the grinding wheel 35b and the upper surface of the wafer W together with grinding chips.

[0043] The grinding water flowing through the other (lower) supply path 53B of the nozzle 53 is supplied toward the upper surface of the wafer W from a plurality of (seven in this embodiment) supply ports 53b opening on the lower surface of the nozzle 53. The grinding water supplied to the upper surface of the wafer W is then supplied to the inside of the grinding wheel 35b as the wafer W rotates, as shown by the arrows in Fig. 5, and flows along the inner peripheral surface as the grinding wheel 35b rotates, and is supplied to the contact portion (grinding portion) between the grinding wheel 35b and the wafer W. As the grinding of the wafer W progresses, the grinding wheel 35b is lowered by the vertical movement mechanism 40, and the nozzle 53 is lowered by the lifting mechanism 70, so that the grinding water is stably sprayed and supplied from the nozzle 53 toward the inside of the grinding wheel 35b and the upper surface of the wafer W from the same height position.

[0044] As described above, when the grinding water is sprayed from the nozzle 53a opening at the tip of the nozzle 53 toward the center of the wafer W inside the grinding wheel 35b and supplied toward the upper surface of the wafer W from the multiple supply ports 53b opening on the underside of the nozzle 53 to the contact area (grinding area) between the grinding wheel 35b and the wafer W, the frictional heat caused by the contact between the grinding wheel 35b and the wafer W is removed by the grinding water, effectively cooling the contact area (grinding area), and the grinding chips generated by grinding the wafer W are washed away and removed by the grinding water.

[0045] As described above, in the grinding apparatus 1 according to this embodiment, a portion of the grinding water supplied from the grinding water supply source 51 to the nozzle 53 arranged inside the grinding wheel 35b along the radial direction of the grinding wheel 35b is supplied toward the upper surface of the wafer W from a plurality of supply ports 53b (seven in this embodiment) opening on the lower surface of the nozzle 53, and this grinding water supplied to the upper surface of the wafer W is supplied to the contact portion (grinding portion) between the wafer W and the grinding wheel 35b by the rotation of the wafer W, and only the remaining grinding water is sprayed toward the inside of the grinding wheel 35b from the spray port 53a opening on the tip surface of the nozzle 53, thereby reducing the load on the spindle motor 32 that rotates the grinding wheel 35b and thereby reducing power consumption.

[0046] Furthermore, grinding water is supplied toward the upper surface of the wafer W from a plurality of supply ports 53b opening on the lower surface of the nozzle 53, and the grinding water is sprayed toward the center of the wafer W from the spray ports 53a opening on the tip surface of the nozzle 53. This allows the entire upper surface of the wafer W, which is the surface to be ground, to be uniformly cooled by the grinding water, and allows grinding debris to be effectively washed away and removed from the wafer W by the grinding water. In particular, if the entire upper surface of the wafer W can be uniformly cooled by the grinding water, the thickness of the wafer W after grinding becomes uniform over the entire area. Incidentally, if the temperature of the wafer W becomes high in part during grinding, the high-temperature part will thermally expand, resulting in a problem that even if the wafer W is ground uniformly, the thickness of the part that became high in temperature during grinding will be thinner at room temperature than other parts.

[0047] As described above, the grinding apparatus 1 according to this embodiment can effectively remove processing heat from the upper surface of the wafer W by using grinding water, and can also effectively wash away and remove grinding debris generated by grinding the wafer W. Therefore, the grinding apparatus 1 is also suitable for grinding wafers W such as lithium tantalate, which generate a lot of grinding debris and are prone to heat generation due to processing heat.

[0048] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Figures 6 and 7. Figure 6 is a perspective view of a grinding device 1' according to the second embodiment of the present invention, and in this figure, the same elements as those shown in Figure 1 are given the same reference numerals, and further description of these elements will be omitted below.

[0049] The grinding apparatus 1' of this embodiment differs only in the configuration of the grinding water supply means 50' from the grinding water supply means 50 of the grinding apparatus 1 of the first embodiment, and the other configurations are the same as the configuration of the grinding apparatus 1 of the first embodiment shown in Figure 1.

[0050] That is, in the grinding apparatus 1' according to this embodiment, as shown in FIG. 7, the grinding water supply means 50' includes a nozzle 53 connected to the lower end of a pipe 56 extending vertically through the center of the grinding unit 30, and a grinding water supply source 51 for supplying grinding water to the nozzle 53. The internal configuration of the grinding unit 30 is shown in FIG. 7. As shown in the figure, a rotatable spindle 33 is housed in the center of a cylindrical motor housing 32a, and a rotor 32A of the spindle motor 32 is attached to the outer periphery of the upper end of the spindle 33. A cylindrical stator 32B of the spindle motor 32 is disposed around the rotor 32A, and a cooling water jacket 32C fixed to the inner periphery of the motor housing 32a is disposed on the outer periphery of the stator 32B. The cooling water jacket 32C has multiple cooling water passages 32b through which cooling water flows.

[0051] The spindle 33, which is rotated at high speed by the spindle motor 32, is supported in a non-contact, floating manner by an air bearing 36. The air bearing 36 is composed of disk-shaped flanges 33A, 33B formed integrally with the top and bottom of the spindle 33, and an annular bearing member 36A fixed to the motor housing 32a and disposed between the top and bottom flanges 33A, 33B of the spindle 33. An air passage 36a is formed inside the bearing member 36A, and one end of the air passage 36a is connected to an air supply source 38 via an air pipe 37. The other end of the air passage 36a is open to the atmosphere via an exhaust port 36b.

[0052] In the air bearing 36 configured as described above, when compressed air is supplied from air supply source 38 to air passage 36a of bearing member 36A via air piping 37, the compressed air is ejected from air passage 36a toward the gap between bearing member 36A and flange portions 33A, 33B of spindle 33, and the pressure of this compressed air provides floating support for spindle 33, which is then rotated at high speed without contact by spindle motor 32. The compressed air flowing through air passage 36a is discharged into the atmosphere from exhaust port 36b.

[0053] Thus, circular holes 33a, 34a that communicate with each other are formed vertically in the axial center of the spindle 33 and the center of the mount 34, and a pipe 56 is inserted vertically into these circular holes 33a, 34a. The upper end of the pipe 56 passes through a circular hole 39a formed in the center of a cover 39 that covers the upper surface of the motor housing 32a, and is connected to the center of a cap 9 that is attached to the center of the cover 39. One end of a pipe 52 is connected to the circular hole 9a formed in the center of the cap 9, and the other end of the pipe 52 is connected to a grinding water supply source 51.

[0054] The lower end of the pipe 56 extends downward from the circular hole 34a of the mount 34, and a nozzle 53 is attached to the lower end. The nozzle 53 is bent at a right angle and arranged horizontally inside the grinding wheel 35b. Like the nozzle 53 in the first embodiment, the nozzle 53 is arranged horizontally inside the grinding wheel 35b along the radial direction of the grinding wheel 35b. Inside the nozzle 53, a pair of horizontally extending circular supply passages 53A, 53B are formed parallel to each other, as shown in Fig. 8. One (upper) supply passage 53A opens obliquely downward toward the inside of the grinding wheel 35b as an injection port 53a on the tip surface of the nozzle 53, and the other (lower) supply passage 53B opens at appropriate intervals in the longitudinal direction as multiple (seven in the illustrated example) supply ports 53b on the lower surface of the tip of the nozzle 53.

[0055] Thus, in the grinding water supply means 50' provided in the grinding apparatus 1' according to this embodiment, similar to the grinding water supply means 50 provided in the grinding apparatus 1 according to the first embodiment, the grinding water sprayed from the nozzle 53a at the tip of one (upper) supply path 53A of the nozzle 53 toward the inside of the grinding wheel 35b is carried along by the rotation of the grinding wheel 35b and is supplied to the contact portion (grinding portion) between the grinding wheel 35b and the wafer W (see Figure 5). In addition, the grinding water flowing through the other (lower) supply path 53B of the nozzle 53 is supplied toward the upper surface of the wafer W from multiple (seven in this embodiment) supply ports 53b opening on the lower surface of the nozzle 53, and the grinding water supplied to the upper surface of the wafer W is supplied to the inside of the grinding wheel 35b as the wafer W rotates, and as it flows along the inner surface as the grinding wheel 35b rotates, it is supplied to the contact area (grinding area) between the grinding wheel 35b and the wafer W (see Figure 5).

[0056] As described above, when the grinding water is sprayed toward the inside of the grinding wheel 35b from the nozzle 53a opening at the tip of the nozzle 53 and supplied toward the upper surface of the wafer W from the multiple supply ports 53b opening at the bottom surface of the nozzle 53 to the contact area (grinding area) between the grinding wheel 35b and the wafer W, the frictional heat caused by the contact between the grinding wheel 35b and the wafer W is removed by the grinding water, effectively cooling the contact area (grinding area), and the grinding chips generated by grinding the wafer W are washed away and removed by the grinding water.

[0057] As described above, the grinding apparatus 1′ according to this embodiment also provides the same effects as those provided by the grinding apparatus 1 according to the first embodiment. That is, a portion of the grinding water supplied from the grinding water supply source 51 to the nozzle 53 disposed inside the grinding wheel 35b along the radial direction of the grinding wheel 35b is supplied toward the upper surface of the wafer W from a plurality of supply ports 53b (seven in this embodiment) opening on the lower surface of the nozzle 53, and the grinding water supplied to the upper surface of the wafer W is supplied to the contact portion (grinding portion) between the wafer W and the grinding wheel 35b by the rotation of the wafer W, and only the remaining grinding water is sprayed toward the inside of the grinding wheel 35b from the spray ports 53a opening on the tip surface of the nozzle 53. Therefore, the load on the spindle motor 32 that rotates the grinding wheel 35b is kept small, and power consumption is reduced.

[0058] In addition, the grinding water supplied from the multiple supply ports 53b opening on the bottom surface of the nozzle 53 toward the top surface of the wafer W can uniformly cool the entire top surface, which is the surface to be ground, and the grinding water sprayed from the spray port 53a opening on the tip surface of the nozzle 53 toward the center of the wafer W can effectively wash away and remove grinding debris from the wafer W and the grinding wheel 35b.

[0059] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims and the technical ideas described in the specification and drawings. [Explanation of symbols]

[0060] 1, 1': grinding device, 2: rotation mechanism, 3: stay, 4: electric motor, 5: driving pulley, 6: driven pulley, 7: timing belt, 8: encoder, 9: cap, 9a: circular hole, 10: chuck table, 10a: communication passage, 11: porous member, 12: piping, 13: suction source, 14: chuck rotation axis, 15: support flange, 16: cover, 17: Telescopic cover, 20: Horizontal movement mechanism, 21: Slider, 22: Guide rail, 23: ball screw, 24: electric motor, 30: grinding unit, 31: holder, 32: spindle motor, 32A: rotor, 32B: stator, 32C: cooling water jacket, 32a: motor housing, 32b: cooling water passage, 33: spindle, 33A, 33B: flange portion, 33a: circular hole, 34: mount, 34a: circular hole, 35: grinding wheel, 35a: base, 35b: grinding stone, 36: air bearing, 36A: bearing member, 36a: air passage, 36b: exhaust port, 37: Air piping, 38: Air supply source, 39: Cover, 39a: Circular hole, 40: Vertical movement mechanism, 41: Lifting plate, 42: Guide rail, 43: Ball screw, 44: Electric motor, 45: bracket; 50, 50': grinding water supply means; 51: grinding water supply source; 52: piping; 53: nozzle, 53A, 53B: supply path, 53a: injection port, 53b: supply port, 54: plug, 55A: movable plate, 54B: arm, 54C: plate, 61A: side plate of the processing chamber, 61B: bottom plate of the processing chamber, 62: partition joint, 63: sealing member, 70: lifting mechanism, 71: support plate, 72: guide rail, 73: slider, 74: ball screw, 75: electric motor, 100: base, 100a: opening of base, 101: internal base, 110: column, S: processing chamber, T: protective tape, W: wafer

Claims

[Claim 1] a chuck table that holds a wafer by a holding surface and rotates around an axis of the center of the holding surface; a grinding unit that rotates an annular grinding wheel about an axis of rotation of the wafer held on the chuck table while passing the grinding wheel through the center of rotation of the wafer; a nozzle for supplying grinding water to the upper surface of the wafer inside the grinding wheel; A grinding device that grinds a wafer as the wafer rotates from the inside to the outside of the grinding wheel, The nozzle is disposed inside the grinding wheel along a radial direction of the grinding wheel, a nozzle formed at a tip thereof for injecting grinding water toward the inner surface of the grinding wheel; a plurality of supply ports for supplying grinding water toward the upper surface of the wafer, the supply ports being formed along the longitudinal direction of the nozzle on the lower surface of the tip of the nozzle;

Images