JP2022136373A - Grinding method of workpiece - Google Patents

Abstract

To provide a grinding method of workpiece which enables reduction of a probability that grinding marks are formed at workpiece even if creep-feed grinding is performed to the workpiece after dressing of grinding wheels.SOLUTION: In a grinding method of workpiece, a grinding machine is operated in a similar manner to an operation during in-feed grinding to perform creep-feed grinding to workpiece after dressing of multiple grinding wheels is performed at a dressing board. The process can inhibit variations in states of the multiple grinding wheels after dressing. As a result, the grinding method can reduce a probability that grinding marks that cause undulation on an upper surface (cause cyclic and fine variations in a thickness) are formed on the workpiece even if creep-feed grinding is performed to the workpiece after dressing of the grinding wheels.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method of grinding a workpiece.

Device chips such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by dividing a workpiece such as a wafer having a large number of devices formed on its surface into regions each including individual devices.

In recent years, in order to reduce the size and weight of chips, the workpiece is often thinned before being divided. As a method for thinning the workpiece, for example, a chuck table for holding the surface (lower surface) of the workpiece by suction with a holding surface, and a chuck table provided above the chuck table and arranged discretely in an annular shape. Grinding by a grinding device having a grinding wheel with a plurality of grinding wheels.

In such a grinding apparatus, a workpiece such as a wafer is often thinned by a grinding method called infeed grinding. In this grinding method, first, the chuck table and the grinding wheel are rotated while the chuck table is positioned above the grinding wheel.

Then, while rotating the chuck table and the grinding wheel, the chuck table and the grinding wheel are vertically moved so that the end surfaces (lower surfaces) of the plurality of grinding wheels and the back surface (upper surface) of the workpiece are brought into contact with each other. to move relative to each other. As a result, the entire rear surface (upper surface) side of the workpiece is ground by the end surfaces (lower surface) of the plurality of grinding wheels. Furthermore, by continuing to move the chuck table and the grinding wheel relative to each other along the vertical direction, a portion having a predetermined thickness on the back surface (upper surface) of the workpiece is removed, thereby thinning the workpiece. be done.

Moreover, in such a grinding apparatus, the workpiece may be thinned by a grinding method called creep feed grinding (see, for example, Patent Document 1). In this grinding method, first, the chuck table and the grinding wheel are separated in the horizontal direction, and the end surfaces (lower surfaces) of the plurality of grinding wheels are lower than the back surface (upper surface) of the workpiece. Rotate the grinding wheel while positioned to be higher than

Then, while rotating the grinding wheel, the chuck table and the grinding wheel are horizontally moved so that the end faces (lower faces) of the outer faces of the plurality of grinding wheels are brought into contact with the side faces of the workpiece. move to As a result, the edge portion having a predetermined thickness on the back surface (upper surface) side of the workpiece is ground by the end surface (lower surface) side and the end surface (lower surface) of the outer surface of each of the plurality of grinding wheels. Furthermore, by continuing to relatively move the chuck table and the grinding wheel along the horizontal direction, the entire back surface (upper surface) side of the workpiece is removed and the workpiece is thinned.

JP-A-2005-28550

The grinding wheel has, for example, a bond material such as vitrified bond or resin bond containing pores, and abrasive grains such as diamond or cubic boron nitride (cBN) dispersed in the bond material. In creep feed grinding, the workpiece is ground by the abrasive grains exposed on the end surface (lower surface) side and the end surface (lower surface) of the outer surfaces of the plurality of grinding wheels.

However, if grinding dust generated by creep feed grinding adheres to the end face (lower surface) and end face (lower surface) of the outer surface of the grinding wheel, Abrasive grains may not be sufficiently exposed (clogging). Further, repeated creep-feed grinding may wear out the abrasive grains exposed on the end face (lower face) and the end face (lower face) of the outer surface of the grinding wheel.

In these cases, there is a risk that the grinding efficiency of the grinding device will be reduced. Therefore, in a grinding apparatus, a process (dressing) is often performed at an appropriate timing to trim the end surfaces (lower surfaces) of a plurality of grinding wheels to prepare them in a state suitable for grinding. Such dressing of the grinding wheel is performed by operating the grinding apparatus in the same manner as grinding the workpiece while the disk-shaped dressing board is held by suction on the chuck table.

Specifically, in a grinding apparatus that performs creep feed grinding, first, the chuck table and the grinding wheel are separated in the horizontal direction, and the end surfaces (lower surfaces) of the plurality of grinding wheels are lower than the upper surface of the dressing board. Rotate the grinding wheel while positioned above the lower surface. Then, while rotating the grinding wheel, the chuck table and the grinding wheel are horizontally moved so that the end surfaces (lower surfaces) of the outer surfaces of the plurality of grinding wheels are brought into contact with the side surfaces of the workpiece. Move relatively.

As a result, the end portions having a predetermined thickness on the end surface (lower surface) side of each of the plurality of grinding wheels are ground by the upper surface side and the upper surface of the side surface of the dressing board. Furthermore, by continuing to relatively move the chuck table and the grinding wheel along the horizontal direction, the entire end surface (lower surface) side of each of the plurality of grinding wheels is ground and the plurality of grinding wheels is dressed (creep feed). dressing).

However, when creep feed grinding is performed on the workpiece after such creep feed dressing, grinding marks with undulating upper surfaces (periodic and minute variations in thickness) are formed on the workpiece. There was found.

In view of this point, the object of the present invention is to reduce the probability that such grinding marks are formed on the workpiece even when creep feed grinding is performed on the workpiece after dressing the grinding wheel. Another object of the present invention is to provide a grinding method for a workpiece that can be processed.

According to the present invention, a chuck table has a holding surface for holding a workpiece, and rotates on a rotation axis that passes through the center of the holding surface and is perpendicular to the holding surface; a grinding unit having a spindle to which a grinding wheel is mounted at the tip thereof, rotating the grinding wheel via the spindle and grinding the workpiece with the plurality of grinding wheels; the chuck table; a first moving mechanism for relatively moving the grinding unit along a first direction parallel to the holding surface; and a first moving mechanism for relatively moving the chuck table and the grinding unit along a second direction perpendicular to the holding surface. and a second moving mechanism for moving the workpiece to the grinding surface, wherein the workpiece is ground by the grinding device, wherein the workpiece is held on the holding surface by holding the dressing board. a first holding step; after the first holding step, the chuck table and After positioning the grinding unit, the chuck table and the grinding wheel are rotated while relatively moving the chuck table and the grinding unit along the second direction to move the chuck table and the grinding unit relative to the dressing board. an infeed dressing step of dressing a plurality of grinding wheels; a second holding step of removing the dressing board from the holding surface after the infeed dressing step and holding the workpiece on the holding surface; after a second holding step, end surfaces of each of the plurality of grinding wheels between the front and back surfaces of the workpiece in the second direction with the grinding wheel spaced from the holding surface in the first direction; and then relatively moving the chuck table and the grinding unit along the first direction while rotating the grinding wheel, thereby holding the workpiece with the plurality of grinding wheels. and a creep feed grinding step of grinding the side away from the face.

In the present invention, by operating the grinding device in the same manner as in infeed grinding, after dressing a plurality of grinding wheels (infeed dressing) on the dressing board, the workpiece is subjected to creep feed grinding. is done.

In this in-feed dressing, not only the grinding wheel but also the chuck table that suction-holds the dressing board is rotated while a plurality of grinding wheels and the dressing board are brought into contact with each other. As a result, even when there is in-plane variation in the dressing board, the end surfaces (lower surfaces) of the plurality of grinding wheels are ground to the same degree.

In addition, in this in-feed dressing, the distance (dressing length) moved while contacting the dressing board is substantially constant for each of the plurality of grinding wheels. On the other hand, in the creep feed dressing described above, the dressing length varies slightly on each of the grinding wheels.

For these reasons, when in-feed dressing is performed, variations in the state of the grinding wheels after dressing can be suppressed more than when creep-feed dressing is performed. As a result, in the present invention, even when creep-feed grinding is performed on the workpiece after dressing the grinding wheel, the grinding marks such as undulating upper surface (thickness periodically and minutely varies) are not produced. can be reduced.

FIG. 1 is a partial cross-sectional side view schematically showing an example of a grinding apparatus. FIG. 2 is a flow chart schematically showing an example of the grinding method. FIG. 3(A) is a perspective view schematically showing the state of the grinding device during the first holding step, and FIG. 3(B) schematically shows the state of the grinding device during the first holding step. It is a partial cross-sectional side view showing. FIG. 4A is a perspective view schematically showing the state of the grinding device during the infeed dressing step, and FIG. 4B schematically shows the state of the grinding device during the infeed dressing step. It is a partial cross-sectional side view showing. FIG. 5(A) is a perspective view schematically showing the state of the grinding device during the second holding step, and FIG. 5(B) schematically shows the state of the grinding device during the second holding step. It is a partial cross-sectional side view showing. FIG. 6(A) is a perspective view schematically showing the state of the grinding device during the creep feed grinding step, and FIG. 6(B) is a schematic state of the grinding device during the creep feed grinding step. It is a partial cross-sectional side view showing.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a partial cross-sectional side view schematically showing an example of a grinding apparatus. Note that the X-axis direction (front-rear direction, first direction) and the Y-axis direction (left-right direction) shown in FIG. ) is a direction perpendicular to the X-axis direction and the Y-axis direction (vertical direction).

A grinding machine 2 shown in FIG. A rectangular parallelepiped opening 4 a is provided on the upper surface side of the base 4 . A chuck table 6 is provided inside the opening 4a. The upper surface of the chuck table 6 is a surface substantially parallel to the X-axis direction and the Y-axis direction, and constitutes a circular holding surface 6a for holding a workpiece or a dressing board.

An X-axis direction moving mechanism (first moving mechanism) 8 is provided inside the opening 4a. The X-axis direction moving mechanism 8 is connected to the chuck table 6 and moves the chuck table 6 along the X-axis direction. This X-axis direction moving mechanism 8 has a screw shaft 10 extending along the X-axis direction.

A motor 12 for rotating the screw shaft 10 is connected to one end of the screw shaft 10 . A nut portion (not shown) for accommodating balls rolling on the surface of the rotating screw shaft 10 is provided on the surface of the screw shaft 10 on which the spiral grooves are formed, thereby forming a ball screw.

That is, when the screw shaft 10 rotates, the balls circulate in the nut portion and the nut portion moves along the X-axis direction. Also, this nut portion is connected to the chuck table 6 . Therefore, when the screw shaft 10 is rotated by the motor 12, the chuck table 6 moves along the X-axis direction together with the nut portion.

Furthermore, the chuck table 6 is connected to a rotation drive source (not shown) such as a motor for rotating the chuck table 6 . This rotational drive source rotates the chuck table 6 around a straight line passing through the center of the holding surface 6a and perpendicular to the holding surface 6a. That is, the rotation axis of the chuck table 6 is set so as to pass through the center of the holding surface 6a and along a direction perpendicular to the holding surface 6a.

A suction path (not shown) is formed inside the chuck table 6 , one end of which is connected to a suction source (not shown) such as an ejector provided outside the chuck table 6 . When the suction source is operated while the workpiece or the dressing board is placed on the holding surface 6a, the workpiece or the dressing board is held on the chuck table 6 by suction.

A rectangular parallelepiped support structure 14 is provided behind the chuck table 6 and the X-axis direction moving mechanism 8 (on the right side of the paper surface of FIG. 1). A Z-axis direction movement mechanism (second movement mechanism) 16 is provided on the surface (front) side of the support structure 14 . The Z-axis direction moving mechanism 16 is connected to a grinding unit 28, which will be described later, and moves the grinding unit 28 along the Z-axis direction.

This Z-axis direction moving mechanism 16 is fixed to the surface side of the support structure 14 and includes a pair of guide rails 18 extending along the Z-axis direction. A moving plate 20 is connected to the front side of the pair of guide rails 18 so as to be slidable along the pair of guide rails 18 .

A screw shaft 22 extending along the Z-axis direction is arranged between the pair of guide rails 18 . A motor 24 for rotating the screw shaft 22 is connected to one end of the screw shaft 22 . A nut portion 26 for accommodating balls rolling on the surface of the rotating screw shaft 22 is provided on the surface of the screw shaft 22 where the helical groove is formed, thereby forming a ball screw.

That is, when the screw shaft 22 rotates, the balls circulate inside the nut portion 26 and the nut portion 26 moves along the Z-axis direction. Also, the nut portion 26 is fixed to the back surface (rear surface) side of the moving plate 20 . Therefore, when the screw shaft 22 is rotated by the motor 24 , the moving plate 20 moves along the Z-axis direction together with the nut portion 26 .

A grinding unit 28 is attached to the surface (front) side of the moving plate 20 . The grinding unit 28 includes a hollow columnar support member 30 fixed to the surface side of the moving plate 20 . A cylindrical housing 32 is accommodated in the support member 30 . The housing 32 is fixed to the bottom wall of the support member 30 via a connecting member 34 provided on its lower surface.

A cylindrical spindle 36 extending along the Z-axis direction is rotatably accommodated in the housing 32 . A tip (lower end) portion of the spindle 36 is exposed from the housing 32 and protrudes downward from the bottom surface of the support member 30 through an opening provided in the bottom wall of the support member 30 . A disk-shaped mount 38 made of metal or the like is fixed to the tip of the spindle 36 .

An annular grinding wheel 40 is attached to the underside of this mount 38 . Grinding wheel 40 is secured to mount 38 by fasteners such as, for example, bolts. The grinding wheel 40 is made of metal such as aluminum or stainless steel and has an annular base 42 formed to have approximately the same diameter as the mount 38 .

The upper surface side of the base 42 is fixed to the lower surface side of the mount 38 . A plurality of grinding wheels 44 are fixed to the lower surface of the base 42 . For example, the plurality of grinding wheels 44 are formed in a rectangular parallelepiped shape and are arranged in a ring at approximately equal intervals along the circumferential direction of the base 42 .

The grinding wheel 44 is formed by fixing abrasive grains such as diamond or cBN (cubic boron nitride) with a bonding material such as metal bond, resin bond or vitrified bond. However, the material, shape, structure, size, etc. of the grinding wheel 44 are not limited. Also, the number of the plurality of grinding wheels 44 is set arbitrarily.

A base end (upper end) of the spindle 36 is connected to a rotation drive source (not shown) such as a motor for rotating the spindle 36 . When this rotational drive source rotates the spindle 36 about a rotation axis along the Z-axis direction, the mount 38 and the grinding wheel 40 rotate together with the spindle 36 .

When the plurality of grinding wheels 44 contact the workpiece held on the chuck table 6 while the grinding wheel 40 is rotating, the upper surface of the workpiece is ground. When the plurality of grinding wheels 44 come into contact with the dressing board held on the chuck table 6 while the grinding wheel 40 is rotating, the plurality of grinding wheels 44 are dressed.

However, when creep feed grinding is performed on the work piece after the creep feed dressing described above, grinding marks with an undulating upper surface (periodic and minute variations in thickness) may be formed on the work piece. found. For example, when the rotation speed of the grinding wheel 40 in creep feed grinding is 2500 rpm and the processing feed rate (the relative movement speed of the chuck table 6 and the grinding wheel 40 in the X-axis direction) is 10 mm/s, the upper surface is It was found that undulating grinding marks were formed on the workpiece with a period of about 0.24 mm.

Here, under the creep feed grinding conditions described above, the chuck table 6 and the grinding wheel 40 move relative to each other by 0.24 (=10/(2500/2500/) along the X-axis direction while the grinding wheel 40 rotates once. 60)) move mm. That is, each of the plurality of grinding wheels 44 contacts the workpiece at intervals of 0.24 mm in the X-axis direction, and grinds the upper surface of the workpiece.

From this, the inventors have found that variations in the states of the plurality of grinding wheels 44 are the cause of the formation of grinding marks as described above. The inventors of the present invention found that such variations in conditions were caused by creep feed dressing, and invented a grinding method as shown in FIG.

FIG. 2 is a flowchart schematically showing an example of a grinding method for grinding the workpiece held on the chuck table 6 using the grinding device 2. As shown in FIG. In this method, first, the dressing board is held on the holding surface 6a of the chuck table 6 (first holding step: S1).

FIG. 3(A) is a perspective view schematically showing the state of the grinding device 2 during the first holding step (S1), and FIG. 3(B) is a 2 is a partial cross-sectional side view schematically showing the state of the grinding device 2 of FIG. The dressing board 1 shown in FIGS. 3(A) and 3(B) has a disk-like shape with a smaller diameter than the holding surface 6a.

The dressing board 1 is formed, for example, by kneading abrasive grains made of silicon carbide (SiC), aluminum oxide (Al ₂ O ₃ ), or the like into a binding material made of vitrified bond, resin bond, or the like, followed by firing. . Furthermore, the dressing board 1 is integrated with the support plate 3 .

The support plate 3 has a disk-like shape with a longer diameter than the dressing board 1 and a shorter diameter than the holding surface 6a. The support plate 3 is made of, for example, a resin such as polyvinyl chloride, and the dressing board 1 is adhered to the center of the upper surface of the support plate 3 via an adhesive. The material, shape, structure, size, etc. of the dressing board 1 and the support plate 3 are not limited.

In the first holding step (S1), first, the X-axis direction moving mechanism 8 moves the chuck table 6 along the X-axis direction so as to separate the chuck table 6 from the grinding unit 28 more than the state shown in FIG. move. Next, with the support plate 3 facing downward, the dressing board 1 is carried into the holding surface 6a (see FIGS. 3A and 3B).

Next, the suction source connected to one end of the suction path formed inside the chuck table 6 is operated. As a result, the dressing board 1 is held by suction on the chuck table 6 via the support plate 3 . That is, the first holding step (S1) is completed.

In the method shown in FIG. 2, after the first holding step (S1), the plurality of grinding wheels 44 are dressed with the dressing board 1 by operating the grinding device 2 in the same manner as in the infeed grinding described above ( In-feed dressing step: S2).

FIG. 4(A) is a perspective view schematically showing the state of the grinding device 2 during the infeed dressing step (S2), and FIG. 4(B) is a 2 is a partial cross-sectional side view schematically showing the state of the grinding device 2 of FIG.

In the in-feed dressing step (S2), first, the rotation trajectories of the plurality of grinding wheels 44 when the grinding wheel 40 is rotated are moved in the X-axis direction so that they are positioned in the Z-axis direction when viewed from the center of the holding surface 6a. A mechanism 8 moves the chuck table 6 along the X-axis direction. Then, the rotary drive source connected to the chuck table 6 rotates the chuck table 6 , and the rotary drive source connected to the base end of the spindle 36 rotates the grinding wheel 40 via the spindle 36 .

Next, while rotating the chuck table 6 and the grinding wheel 40, the Z-axis direction moving mechanism 16 moves the grinding unit 28 so that the end surfaces (lower surfaces) of the plurality of grinding wheels 44 and the upper surface of the dressing board 1 are brought into contact with each other. Move along the Z-axis direction (see FIGS. 4A and 4B). As a result, the end surface (lower surface) side of each of the plurality of grinding wheels 44 is ground by the upper surface of the dressing board 1 . Furthermore, the Z-axis direction moving mechanism 16 continues to move the grinding unit 28 along the Z-axis direction, so that the portions having a predetermined thickness on the end surface (lower surface) side of the plurality of grinding wheels 44 are ground, resulting in a plurality of grinding wheels. of the grinding wheel 44 are dressed.

When the dressing of the plurality of grinding wheels 44 is completed in this manner, the rotation of the chuck table 6 and the grinding wheel 40 is stopped, and the end surfaces (lower surfaces) of the plurality of grinding wheels 44 and the upper surface of the dressing board 1 are separated. The Z-axis direction moving mechanism 16 moves the grinding unit 28 along the Z-axis direction. By the above, the infeed dressing step (S2) is completed.

In the method shown in FIG. 2, after the infeed dressing step (S2), the workpiece is held on the holding surface 6a of the chuck table 6 (second holding step: S3). FIG. 5(A) is a perspective view schematically showing the state of the grinding device 2 during the second holding step (S3), and FIG. 5(B) is a 2 is a partial cross-sectional side view schematically showing the state of the grinding device 2 of FIG.

The workpiece 11 shown in FIGS. 5A and 5B has a disk-like shape with a smaller diameter than the holding surface 6a. The workpiece 11 is a disk-shaped wafer made of a semiconductor material such as Si (silicon), SiC (silicon carbide), or GaN (gallium nitride), and has a large number of devices such as ICs or LSIs on its surface. is formed.

A disk-shaped protective tape having the same diameter as the workpiece 11 may be attached to the surface of the workpiece 11 . When the protective tape is attached to the surface of the workpiece 11 in this way, the impact applied to the device when the workpiece 11 is ground is reduced, and the probability of the device being damaged can be reduced. Moreover, the device may not be formed on the workpiece 11 .

In the second holding step ( S<b>3 ), first, the X-axis direction moving mechanism 8 moves the chuck table 6 along the X-axis direction so as to separate the chuck table 6 from the grinding unit 28 . Next, the operation of the suction source connected to one end of the suction path formed inside the chuck table 6 is stopped. Next, the dressing board 1 integrated with the support plate 3 is carried out from the holding surface 6a.

Next, the workpiece 11 is carried into the holding surface 6a so that the surface faces downward (see FIGS. 5(A) and 5(B)). Next, the suction source connected to one end of the suction path formed inside the chuck table 6 is operated. As a result, the workpiece 11 is held on the chuck table 6 by suction. That is, the second holding step (S3) is completed.

In the method shown in FIG. 2, after the second holding step (S3), the side far from the holding surface 6a of the workpiece 11 (back surface (upper surface) side) is ground (creep feed grinding) with a plurality of grinding wheels 44. (Creep feed grinding step: S4). FIG. 6(A) is a perspective view schematically showing the state of the grinding apparatus 2 during the creep feed grinding step (S4), and FIG. 6(B) is a perspective view during the creep feed grinding step (S4) 2 is a partial cross-sectional side view schematically showing the state of the grinding device 2 of FIG.

In the creep feed grinding step (S4), first, the end surfaces (lower surfaces) of the plurality of grinding wheels 44 are lower than the back surface (upper surface) of the workpiece 11 and higher than the surface (lower surface) thereof. A directional movement mechanism 16 moves the grinding unit 28 along the Z-axis direction. A rotary drive source coupled to the proximal end of spindle 36 then rotates grinding wheel 40 via spindle 36 .

Next, while the grinding wheel 40 is being rotated, the X-axis direction moving mechanism 8 moves the chuck table 6 so that the end surfaces (lower surfaces) of the outer surfaces of the plurality of grinding wheels 44 are brought into contact with the side surfaces of the workpiece 11 . Move along the X-axis direction (see FIGS. 6A and 6B). As a result, the edge portion having a predetermined thickness on the back surface (upper surface) side of the workpiece 11 is ground by the end surface (lower surface) side and the end surface (lower surface) of the outer surfaces of the plurality of grinding wheels 44 . . Further, the X-axis direction moving mechanism 8 continues to move the chuck table 6 along the X-axis direction, so that the entire back surface (upper surface) side of the workpiece 11 is ground and the workpiece 11 is thinned. be.

When the workpiece 11 is thinned in this way, the rotation of the grinding wheel 40 is stopped and the Z-axis is moved so as to separate the end surfaces (lower surfaces) of the plurality of grinding wheels 44 from the upper surface of the dressing board 1 . A directional movement mechanism 16 moves the grinding unit 28 along the Z-axis direction. The above completes the creep feed grinding step (S4).

In the method shown in FIG. 2, creep-feed grinding is performed on the workpiece 11 after the in-feed dressing of the grinding wheels 44 is performed on the dressing board 1 .

In this in-feed dressing, not only the grinding wheel 40 but also the chuck table 6 for sucking and holding the dressing board 1 are rotated while the plurality of grinding wheels 44 and the dressing board 1 are brought into contact with each other. As a result, even when the dressing board 1 has in-plane variations, the end surfaces (lower surfaces) of the plurality of grinding wheels 44 are ground to the same degree.

Further, in this in-feed dressing, the distance (dressing length) moved while contacting the dressing board 1 is substantially constant for each of the plurality of grinding wheels 44 . On the other hand, when a plurality of grinding wheels 44 are dressed (creep feed dressing) by operating the grinding apparatus 2 in the same manner as creep feed grinding, the dressing length of each of the plurality of grinding wheels 44 is slightly reduced. Change.

For these reasons, when in-feed dressing is performed, variations in the state of the grinding wheels 44 after dressing can be suppressed as compared to when creep-feed dressing is performed. As a result, in the method shown in FIG. 2, even when creep-feed grinding is performed on the workpiece 11 after dressing the grinding wheel 44, the upper surface of the workpiece 11 is undulating (thickness periodically and minutely). It is possible to reduce the probability that grinding traces (such as those that vary) are formed on the workpiece 11 .

Note that the above method is one embodiment of the present invention, and the present invention is not limited to the above method. For example, in the present invention, the chuck table 6 may be configured to move in the Y-axis direction and/or the Z-axis direction, and the grinding unit 28 may move in the X-axis direction and/or the Y-axis direction. It may be configured as possible.

In addition, the structure, method, and the like according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention.

2: grinding device 4: base (4a: opening)
6: Chuck table (6a holding surface)
8: X-axis movement mechanism (first movement mechanism)
10: screw shaft 12: motor 14: support structure 16: Z-axis direction movement mechanism (second movement mechanism)
18: Guide rail 20: Moving plate 22: Screw shaft 24: Motor 26: Nut part 28: Grinding unit 30: Support member 32: Housing 34: Connection member 36: Spindle 38: Mount 40: Grinding wheel 42: Base 44: Grinding Wheel 1: Dressing Board 3: Support Plate 11: Workpiece

Claims (1)

a chuck table that has a holding surface that holds a workpiece and that rotates on a rotation axis passing through the center of the holding surface and perpendicular to the holding surface;
A grinding unit having a spindle to which a grinding wheel having a plurality of grinding wheels arranged in an annular shape is attached to the tip thereof, and rotating the grinding wheel through the spindle to grind the workpiece with the plurality of grinding wheels. When,
a first moving mechanism that relatively moves the chuck table and the grinding unit along a first direction parallel to the holding surface;
a second movement mechanism for relatively moving the chuck table and the grinding unit along a second direction perpendicular to the holding surface;
A method of grinding a workpiece for grinding the workpiece held on the chuck table using a grinding device comprising
a first holding step for holding the dressing board on the holding surface;
After the first holding step, positioning the chuck table and the grinding unit such that the rotational trajectories of the plurality of grinding wheels when the grinding wheel is rotated are positioned in the second direction with respect to the holding surface. Then, while rotating the chuck table and the grinding wheel, the chuck table and the grinding unit are relatively moved along the second direction to dress the plurality of grinding wheels with the dressing board. an infeed dressing step to
a second holding step, after the infeed dressing step, removing the dressing board from the holding surface and holding the workpiece on the holding surface;
After the second holding step, each of the plurality of grinding wheels is positioned between the front and back surfaces of the workpiece in the second direction with the grinding wheel spaced from the holding surface in the first direction. After positioning the end face, the chuck table and the grinding unit are moved relative to each other along the first direction while the grinding wheel is rotated, thereby grinding the workpiece with the plurality of grinding wheels. a creep feed grinding step grinding the side remote from the holding surface;
A grinding method for a workpiece, comprising:

Images