JP2022161165A - Method for grinding bent plate-like workpiece - Google Patents

Abstract

To reduce grindstone replacing work and eliminate necessity of stockpiling a plurality of types of grindstones when bent plate-like workpiece is ground by reducing force for separating the bent plate like workpiece from a holding surface.SOLUTION: A plate-like workpiece grinding method comprises steps of: holding bent plate-like workpiece having force in a direction in which an outer peripheral part is separated from a holding surface 302 on the holding surface 302 of a table 3, lowering a grindstone 1642 positioned above the plate-like workpiece in a direction perpendicular to the holding surface 302, and biting the grindstone 1642 into the plate-like workpiece to form a circular-arc groove without rotating the holding surface 302; relatively moving at least one of the grindstone 1642 and the table 3 so as to position the grindstone 1642 to a location different from the location of the grindstone 1642 positioned with respect to the plate-like workpiece in the circular-arc groove forming step; repeating the circular-arc groove forming step and the grindstone moving step to form a plurality of grooves on the upper surface of the plate-like workpiece, thereby correcting the bending; and grinding, after the grooves have been formed, the upper surface of the plate-like workpiece to remove the grooves, and grinding the workpiece to a prescribed thickness.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method of grinding a plate-like work by grinding a curved plate-like work with a grinding wheel.

For example, as disclosed in Patent Document 1 below, when a plate-shaped work having a force that causes the outer peripheral portion to be suction-held on the holding surface of the chuck table to warp with a grinding wheel, the grinding wheel and the plate-like work, and the warping force of the plate-like work, the outer peripheral portion of the plate-like work may be lifted from the holding surface, and the plate-like work may be separated from the holding surface.

Then, in order to prevent the curved plate-shaped work from separating from the holding surface, cutting grooves are formed on the upper surface of the plate-shaped work, which is the surface to be ground, before grinding, and the curvature of the plate-shaped work is corrected and warped. weakening power.

JP 2015-223667 A

Conventionally, a cutting grindstone is used to form cutting grooves in this plate-shaped work. Therefore, the processing apparatus includes a cutting mechanism equipped with a cutting wheel for forming grooves in the plate-shaped work, and a grinding mechanism equipped with a grinding wheel for grinding and thinning the plate-shaped work. Grinding wheels may be replaced frequently by an operator, and it is necessary to replace two types of grinding wheels and keep two types of grinding wheels in stock.

Therefore, when grinding a plate-like workpiece that is curved upwards, reducing the force that tends to separate it from the holding surface of the chuck table of the grinding device due to the curvature, it is necessary to replace the grinding wheel. There is a problem of reducing the frequency and eliminating the need to stock multiple types of whetstones.

In order to solve the above problems, the present invention provides a plate-shaped workpiece for grinding the upper surface of a curved plate-shaped work having a force in a direction in which the outer peripheral portion held by the holding surface of a chuck table separates from the holding surface with an annular grinding wheel. A method of grinding a work, wherein the chuck table holds the plate-like work on the holding surface, and the grinding wheel positioned above the plate-like work held on the holding surface is perpendicular to the holding surface. an arc groove forming step in which the grinding wheel is cut into the upper surface of the plate-like work without rotating the holding surface to form an arc groove; A grinding wheel that relatively moves at least one of the grinding wheel and the chuck table in a direction parallel to the holding surface so as to position the grinding wheel at a position different from the position of the grinding wheel positioned against the grinding wheel. a multiple groove forming step of repeating the moving step, the arc groove forming step, and the grinding wheel moving step to form a plurality of the grooves on the upper surface of the plate-like work to correct the curvature of the plate-like work; a grinding step of forming a plurality of grooves, grinding the upper surface of the plate-like work to remove the grooves, and grinding the plate-like work to a predetermined thickness. be.

In the method for grinding a plate-like work according to the present invention, the grinding step includes rotating the chuck table around the center of the holding surface, and passing through the center of rotation of the plate-like work held on the rotating holding surface. Preferably, the grinding wheel is lowered in a direction perpendicular to the holding surface to grind the plate-shaped work.

In the method for grinding a plate-shaped work according to the present invention, the grinding step includes positioning the lower surface of the grinding wheel outside the outer periphery of the plate-shaped work held on the holding surface and below the upper surface of the plate-shaped work, It is preferable to grind the plate-like work by bringing the plate-like work and the grinding wheel relatively closer together in a direction parallel to the holding surface.

In the method for grinding a plate-like workpiece according to the present invention, the step of forming the circular arc groove relatively changes the inclination of the holding surface of the chuck table with respect to the lower surface of the grinding wheel so that the outer peripheral angle of the lower surface of the grinding wheel is It is preferable to cut into the upper surface of the plate-like work held by the holding surface.

In the method for grinding a plate-like workpiece according to the present invention, the step of forming the circular arc groove relatively changes the inclination of the holding surface of the chuck table with respect to the lower surface of the grinding wheel, and It is preferable to cut the upper surface of the plate-like work held by the holding surface from the corner.

A method of grinding a plate-shaped work according to the present invention, in which the upper surface of a curved plate-shaped work held by a holding surface of a chuck table and having a force in a direction in which the outer peripheral portion is separated from the holding surface is ground with an annular grinding wheel. holds the plate-like work on the holding surface, lowers the grinding wheel positioned above the plate-like work held on the holding surface in a direction perpendicular to the holding surface, and removes the upper surface of the plate-like work without rotating the holding surface. A circular arc groove forming step for forming circular arc grooves by cutting a grinding wheel into the groove; A grinding wheel moving step of relatively moving at least one of the grinding wheel and the chuck table in a direction parallel to the holding surface, an arc groove forming step, and a grinding wheel moving step are repeated to form a plate-shaped work. a plurality of grooves forming step of forming a plurality of grooves on the upper surface to correct the curvature of the plate-like work, so that the plate-like work separates from the holding surface before the plate-like work is ground and thinned. Therefore, after forming a plurality of grooves, the upper surface of the plate-shaped work is ground to remove the grooves, and the vacuum is applied so that the plate-shaped work does not separate from the holding surface. It is possible to grind a plate-shaped work to a predetermined thickness while preventing the occurrence of leaks. In addition, since grooving and grinding are performed using only grinding wheels, the number of types of grinding wheels can be reduced, and it is not necessary to stock multiple types of grinding wheels in the grinding apparatus.

In the grinding process, the chuck table is rotated around the center of the holding surface, and the grinding wheel passing through the center of rotation of the plate-shaped work held on the rotating holding surface is lowered in a direction perpendicular to the holding surface to remove the plate-shaped work. By grinding, that is, by infeed grinding, it is possible to remove the grooves, flatten the upper surface of the plate-like work, and thin the plate-like work to a predetermined thickness.

In the grinding process, the lower surface of the grinding wheel is positioned outside the outer periphery of the plate-like work held on the holding surface and below the upper surface of the plate-like work, and the plate-like work and the grinding wheel are placed relative to each other in a direction parallel to the holding surface. Grind the plate-like work by approaching to, that is, by creep feed grinding, removing the groove to make the upper surface of the plate-like work flat and thinning the plate-like work appropriately to a predetermined thickness becomes possible.

In the arc groove forming process, the tilt of the holding surface of the chuck table relative to the lower surface of the grinding wheel is changed, and the upper surface of the plate-like workpiece held by the holding surface is cut from the outer peripheral angle of the lower surface of the grinding wheel. , it becomes possible to appropriately form grooves for correcting the curvature of the plate-like work.

In the arc groove forming step, the inclination of the holding surface of the chuck table relative to the lower surface of the grinding wheel is changed, and the upper surface of the plate-like workpiece held by the holding surface is cut from the inner peripheral angle of the lower surface of the grinding wheel. Therefore, it is possible to appropriately form the grooves for correcting the curvature of the plate-shaped work. In addition, in the grinding process performed after performing the multiple groove forming process in which the circular arc groove forming process and the grinding wheel moving process are repeated, for example, when creep feed grinding is performed, the part where the plate-like work is mainly ground by creep feed grinding It is possible to avoid wearing out the outer surface of the grinding wheel, which is to be used for creep feed grinding.

It is a perspective view which shows an example of the grinding apparatus used for the grinding method. It is a sectional view explaining tabular curvature. It is a side view which shows an example of a grinding apparatus. FIG. 5 is a plan view for explaining arc-shaped grooves that are formed on the upper surface of a plate-shaped work and cross from one outer peripheral side of the plate-shaped work to the other outer peripheral side thereof by performing the arc-shaped groove forming step and the grinding wheel moving step of Embodiment 1; is. A plurality of groove forming steps are performed by repeating the arc groove forming step and the grinding wheel moving step of Embodiment 1, and arc grooves crossing from one outer peripheral side of the plate-shaped work to the other outer peripheral side are formed over the entire upper surface. It is a top view explaining the state which was made. A state in which arc-shaped grooves crossing the plate-like work from end to end are formed on the entire upper surface by performing the multiple-groove forming step of repeating the arc-shaped groove forming step and the grinding wheel moving step of Embodiment 1 will be described. It is a perspective view. When performing the arc groove forming step of Embodiment 2, the inclination of the holding surface of the chuck table with respect to the lower surface of the grinding wheel is changed relatively so that the upper surface of the plate-shaped work held is shifted from the outer peripheral corner of the lower surface of the grinding wheel. FIG. 3 is a side view of a portion of the grinding device set to cut; A plane for explaining a state in which arc-shaped grooves are formed in both regions of the upper surface of the plate-like workpiece in the ±X direction by performing the arc-groove forming step of Embodiment 2 and the grinding wheel moving step repeatedly. It is a diagram. FIG. 11 is a plan view for explaining a state in which arc grooves are formed substantially all over the upper surface of a plate-like workpiece by carrying out a plurality of groove formation steps of repeating the arc groove formation step and the grinding wheel movement step of Embodiment 2; A plane for explaining a state in which many arcuate grooves are formed in the upper surface of the plate-shaped work, especially in four corner regions, by performing the arcuate groove forming step of Embodiment 3 and the grinding wheel moving step, and performing the multiple groove forming step. It is a diagram. A plate-like workpiece held by the holding surface from the inner peripheral angle of the lower surface of the grinding wheel by changing the inclination of the holding surface of the chuck table relative to the lower surface of the grinding wheel when performing the arc groove forming step of the fourth embodiment. 1 is a side view of a portion of the grinding device set to cut into the upper surface of the . A state in which many arcuate grooves are formed in both the ±X direction areas of the top surface of the plate-like workpiece by performing the arcuate groove forming step of the fourth embodiment and the grinding wheel moving step are repeated to form a plurality of grooves. It is a plan view to do. When the inner diameter of the grinding wheel is smaller than the length of the plate-like work, the arc groove forming step of Embodiment 4 and the grinding wheel moving step are repeated to form a plurality of grooves, and 2 is a plan view for explaining a state in which many circular grooves are formed in both areas of .

The grinding apparatus 1 shown in FIG. 1 is an apparatus for grinding a plate-like workpiece 90 sucked and held on a chuck table 3 by a grinding unit 16. The front side (−Y direction side) is an attachment/detachment area where the plate-like workpiece 90 is attached to and detached from the chuck table 3 , and the rear side (+Y direction side) on the device base 10 is an area on the chuck table 3 by the grinding unit 16 . is a grinding area in which the plate-like workpiece 90 held by suction is ground.
It should be noted that the grinding apparatus used for carrying out the grinding method according to the present invention is not limited to the type in which the grinding unit 16 of the grinding apparatus 1 has a single axis, but includes a rough grinding unit and a finish grinding unit, and rotates. A two-axis type turntable may be used in which the plate-like workpiece 90 can be positioned below the rough grinding unit or the finish grinding unit.

The plate-shaped workpiece 90 shown in FIG. 1 has, for example, silicon chips arranged at regular intervals on the upper surface of a rectangular substrate made of PCB or the like, and the upper surface of the substrate including the silicon chips is molded with epoxy resin or the like. there is The entire plate-like work 90 having a rectangular shape in a plan view is curved due to the shrinkage force of the mold resin and the like. That is, as shown in FIG. 2, the curvature of the plate-like work 90 is, for example, such that the lower surface 902 of the plate-like work 90, which is held by suction, gradually increases in height from the central region toward the outer peripheral region. be. An upper surface 904 of the plate-like work 90 is a surface to be ground, and a protective tape 9000 is attached to a lower surface 902 of the plate-like work 90 to protect the lower surface 902 .
It should be noted that the plate-like workpiece 90 having a polygonal (rectangular) shape in the present embodiment is not limited to this, and may be a silicon wafer or the like that is circular in plan view.

The chuck table 3 shown in FIGS. 1 and 3 includes, for example, a porous section 30 having a rectangular holding surface 302 and a frame 31 supporting the porous section 30 . The holding surface 302 communicates with a suction source (not shown) such as a vacuum generator or an ejector mechanism.

As shown in FIG. 1, the chuck table 3 is surrounded by a cover 39, and is rotated by a table rotation mechanism 33 including a rotation shaft, a motor, an encoder for detecting the rotation angle of the motor, and the like. It is rotatable with the shaft as the axis of rotation.

As shown in FIG. 1 , inside the device base 10 , there are a grinding position where the grinding wheel 164 grinds the plate-like work 90 , and a plate-like work 90 is carried into the holding surface 302 of the chuck table 3 or is moved from the holding surface 302 to the plate-like work 90 . A horizontal movement unit 13 for horizontally moving the chuck table 3 is disposed at a loading/unloading position where the workpiece 90 can be unloaded.
The horizontal movement unit 13 includes a ball screw 130 having an axis in the Y-axis direction, a pair of guide rails 131 arranged parallel to the ball screw 130, and a motor 132 connected to one end of the ball screw 130 to rotate the ball screw 130. , and a movable plate 133 having an internal nut screwed onto the ball screw 130 and a bottom portion slidably contacting the guide rail 131 . It is guided and moves linearly in the Y-axis direction, and as shown in FIGS. The provided chuck table 3 can be moved in the Y-axis direction.
The horizontal movement unit 13 may be a rotatable turntable on which a plurality of chuck tables 3 are arranged.

As shown in FIG. 1 , the chuck table 3 is attached to the upper surface of the chuck base 35 , and the chuck base 35 is supported by an inclination adjusting portion 37 that adjusts the inclination of the holding surface 302 of the chuck table 3 .
As shown in FIG. 3 , on the movable plate 133 of the horizontal movement unit 13 , the inclination adjustment part 37 is provided on the lower surface side of the chuck base 35 in a circular shape around the center of the holding surface 302 of the chuck table 3 . Two or more are provided at equal intervals. That is, for example, two tilt adjusting portions 37 and a support column extending in the Z-axis direction (not shown) for fixing the chuck base 35 are arranged at intervals of 120 degrees on a circumference. The two tilt adjusting units 37 are, for example, an electric cylinder, an air cylinder, or the like in which the piston rod 371 can move up and down in the Z-axis direction. By vertically moving the piston rods 371 of the two tilt adjusting portions 37 shown in FIG. 3, the tilt of the holding surface 302 with respect to the lower surface of the grinding wheel 1642 of the grinding unit 16 can be adjusted.
In addition, the inclination adjusting section may be arranged on the grinding unit 16 side.

As shown in FIG. 1, a column 11 is erected in the grinding area. An elevating unit 17 is provided for grinding and feeding in the Z-axis direction. The lifting unit 17 includes a ball screw 170 extending in the Z-axis direction, a pair of guide rails 171 arranged parallel to the ball screw 170, a lifting motor 172 connected to the upper end of the ball screw 170 and rotating the ball screw 170, The elevator plate 173 has an internal nut that is screwed onto the ball screw 170 and a side portion of which is in sliding contact with the guide rail 171 . , and the grinding unit 16 fixed to the lifting plate 173 is fed for grinding in the Z-axis direction.

The grinding unit 16 that grinds the plate-like workpiece 90 held on the chuck table 3 includes a rotating shaft 160 whose axial direction is the Z-axis direction, a housing 161 that rotatably supports the rotating shaft 160, and a rotating shaft 160 that rotates. A driving motor 162 , an annular mount 163 connected to the lower end of a rotating shaft 160 , a grinding wheel 164 detachably attached to the lower surface of the mount 163 , and an elevating plate 173 of the elevating unit 17 supporting the housing 161 . and a holder 165 fixed to the .

The grinding wheel 164 includes a wheel base 1641 and a plurality of substantially rectangular parallelepiped grinding wheels 1642 annularly arranged on the bottom surface of the wheel base 1641 . The grinding wheel 1642 is formed by bonding diamond abrasive grains or the like with resin bond, vitrified bond, or the like, for example. The edge width of the ring-shaped grinding wheel 1642 is set to, for example, 1 mm to 3 mm.

For example, the diameter of the grinding wheel 164 is larger than that of the plate-shaped work 90 so that the arc-shaped grinding wheel 1642 can traverse from one side of the plate-shaped work 90 to the opposite side with a sufficient margin. .
Note that the diameter of the grinding wheel 164 may be smaller than the size of the plate-like workpiece 90 when the circular groove forming step of Embodiment 4 described later regarding the grinding direction according to the present invention is not performed.

Inside the rotating shaft 160, a flow path (not shown) that communicates with the grinding water supply source and serves as a path for the grinding water is provided through the rotating shaft 160 in the axial direction. Through the mount 163 , an opening is formed on the bottom surface of the wheel base 1641 so that grinding water can be jetted toward the grinding wheel 1642 .

In this embodiment, the grinding unit 16 and the lifting unit 17 can be reciprocated in the X-axis direction by an X-axis moving unit 18 arranged on the front surface of the column 11, for example.
The X-axis moving unit 18 includes a ball screw 180 whose axial direction is the X-axis direction, a pair of guide rails 181 arranged parallel to the ball screw 180, and a motor 182 connected to one end of the ball screw 180 and rotating the ball screw 180. and a movable plate 183 whose inner nut is screwed onto the ball screw 180 and whose side portion is in slidable contact with the guide rail 181. Guided by 181, it reciprocates in the X-axis direction, and the grinding unit 16 and lifting unit 17 arranged on the movable plate 183 reciprocate in the X-axis direction.

As shown in FIG. 1, at a position adjacent to the grinding unit 16 lowered to the grinding position, for example, a thickness measuring section 104 for measuring the thickness of the plate-like workpiece 90 by contact is arranged. The thickness measurement unit 104 measures the height position of the holding surface 302 serving as the reference surface, that is, the height of the upper surface of the frame 31 at the same height position as the holding surface 302 in this embodiment, using the first linear gauge. By measuring the position, measuring the height position of the upper surface 904 of the plate-like work 90 to be ground with the second linear gauge, and calculating the difference between the measured values of both linear gauges, the thickness of the plate-like work 90 is calculated. It can be measured sequentially during grinding.
Note that the thickness measuring unit 104 may be of a non-contact type.

For example, a plate-like workpiece 90 placed on the holding surface 302 of the chuck table 3 for suction holding is placed at a position beside the movement path of the chuck table 3 in the attachment/detachment area on the apparatus base 10 shown in FIG. A pressing mechanism 4 that presses downward from above is provided.

The pressing mechanism 4 includes a lifting mechanism 40 such as an electric cylinder or an air cylinder disposed on the apparatus base 10, and a lifting rod (not shown) that moves up and down in the Z-axis direction of the lifting mechanism 40. It is provided with an arm portion 41 horizontally extending up to the movement path of the table 3 and a pressing pad 44 attached to the lower surface of the tip of the arm portion 41 . The arm part 41 can turn and move within a horizontal plane (within an X-axis and Y-axis plane), for example, about a rotation axis in the Z-axis direction.

The pressing pad 44, which can be moved up and down in the Z-axis direction by the lifting mechanism 40 and which can be aligned with the center of the holding surface 302 of the chuck table 3 in the Z-axis direction and can face the plate-shaped work 90 in plan view, for example. , or a rectangle slightly larger than the plate-shaped work 90 . A flat lower surface 443 of the pressing pad 44 contacts the upper surface 904 of the plate-like workpiece 90 .

In the following, each process and each configuration of the grinding apparatus 1 when the grinding method according to the present invention is performed to grind the plate-like workpiece 90 held on the chuck table 3 by the grinding apparatus 1 shown in FIG. Operation will be explained.
First, the chuck table 3 shown in FIGS. 1 and 3 is moved in the −Y direction by the horizontal movement unit 13 and positioned directly below the pressing pad 44 of the pressing mechanism 4 in the attachment/detachment area, for example. Further, the pressing pad 44 arranged at the tip of the arm portion 41 is rotated about the rotating shaft 45 passing through the center of the lifting mechanism 40, so that the shape of the pressing pad 44 and the shape of the holding surface 302 of the chuck table 3 are substantially adjusted. match.

Next, for example, as shown in FIG. 3, the plate-like work 90 is aligned with the holding surface 302 of the chuck table 3 by an operator, and the shape of the holding surface 302 and the shape of the plate-like work 90 are aligned. are placed on the holding surface 302 in a state in which they are substantially aligned with each other. Here, the plate-like workpiece 90 is arranged on the holding surface 302 so as to gradually increase in height from the central region of the lower surface 902 toward the outer peripheral region.

A suction source (not shown) operates to generate a suction force that is transmitted to the holding surface 302 so that the chuck table 3 moves on the holding surface 302 to the center region (in this embodiment, the lower surface 902 of the plate-like workpiece 90). The center area of the lower surface of the protective tape 9000) is first held by suction.

Further, the lifting mechanism 40 shown in FIG. 1 lowers the pressing pad 44 at a predetermined speed. The pressing pad 44 presses the plate-like work 90 so that the outer peripheral region of the lower surface 902 of the plate-like work 90 corrects the curvature of the holding surface 302 . Then, the plate-like work 90 is held by suction on the chuck table 3 with no vacuum leak, with the warp of the outer peripheral portion, that is, the curving of the whole, being temporarily eliminated. Without forming a groove, which will be described later, on the upper surface 904 of the plate-like work 90, the grinding wheel 1642 is kept in contact with the upper surface 904 of the plate-like work 90, and the plate-like work 90 is rotated by the chuck table 3, for example. , the frictional force acting between the grinding wheel 1642 and the upper surface 904 of the plate-like work 90 restores the curvature of the plate-like work 90 during grinding, causing vacuum leaks and the like. Sometimes.

After the plate-like work 90 is sucked and held on the chuck table 3 in a state in which the curvature is temporarily canceled, the pressing pad 44 rises and separates from the plate-like work 90 .
Next, the horizontal movement unit 13 moves the chuck table 3 holding the plate-like work 90 under the grinding unit 16 shown in FIGS. be.

(1-1) Embodiment 1 of Arc Groove Forming Step
Next, the grinding wheel 1642 positioned above the plate-like workpiece 90 sucked and held on the holding surface 302 of the chuck table 3 shown in FIG. A description will be given of the arc groove forming step of Embodiment 1, in which arc grooves are formed by cutting the grinding wheel 1642 into the upper surface 904 of the plate-like work 90 without rotating the plate-like workpiece 90 .

For example, in the first embodiment, the inclination of the chuck base 35 and the chuck table 3 is adjusted by the inclination adjustment unit 37 shown in FIG. are substantially parallel to the lower surface of the grinding wheel 1642 .

Next, the grinding unit 16 is moved in the X-axis direction by the X-axis movement unit 18 shown in FIGS. The grinding unit 16 and the chuck table 3 are aligned in the X-axis direction so that the center of the holding surface 302 (that is, the center of the plate-like workpiece 90) is positioned.

Next, the motor 132 of the horizontal movement unit 13 rotates the ball screw 130 by a predetermined angle and then stops for a predetermined period of time. By repeating this operation, the chuck table 3 is stopped after moving a predetermined distance in the Y-axis direction, and after a predetermined period of time has passed, it is again rotated in the Y-axis direction. performs a step movement to move a predetermined distance to

The upper surface 904 of the plate-like work 90 sucked and held by the chuck table 3 that is step-moved in the +Y direction by the horizontal movement unit 13 is positioned below the grinding wheel 1642 so that the edge region of the chuck table 3 is positioned below the grinding wheel 1642 . Movement stops.
Next, when the lifting unit 17 lowers the grinding unit 16 in the −Z direction at a predetermined grinding feed rate, the grinding wheel 1642 rotating at a predetermined rotational speed contacts the upper surface 904 of the plate-like workpiece 90 .

At this time, in this embodiment, the upper surface 904 of the plate-like workpiece 90 held by the holding surface 302 is cut from the lower surface (flat surface) of the grinding wheel 1642 . By not rotating the holding surface 302 of the chuck table 3, a single arcuate groove 907 shown in FIG. For example, the width of the arcuate groove 907 is approximately the same as the blade width of the grinding wheel 1642 .

The grinding wheel 1642 shown in FIG. 3 cuts into the upper surface 904 to a position above the finished thickness of the plate-like workpiece 90 to form the arcuate groove 907 shown in FIG. 17 raises the grinding unit 16 so that the grinding wheel 1642 is once separated from the plate-like workpiece 90 .

(2-1) Grinding wheel moving process after the arc groove forming process of the first embodiment In order to position the grinding wheel 1642 , at least one of the grinding wheel 1642 and the chuck table 3 is relatively moved in the horizontal direction parallel to the holding surface 302 . In this embodiment, the horizontal movement unit 13 shown in FIG. A grinding wheel 1642 of the grinding unit 16 is positioned above the area where the burr has not yet been formed.

(3-1) Multiple groove forming step of repeating the circular arc groove forming step and the grinding wheel moving step of Embodiment 1 Again, the lifting unit 17 shown in FIG. 3 lowers the grinding unit 16 in the −Z direction at a predetermined grinding feed rate, and the rotating grinding wheel 1642 is placed on the upper surface 904 of the plate-like workpiece 90 from the flat lower surface to a predetermined depth. A second arcuate groove 907 shown in FIG. 4 is formed by cutting.
Then, a grinding wheel moving step similar to that described above is performed. In this way, by repeating the arcuate groove forming process and the grinding wheel moving process, a plurality of arcuate grooves 907 are formed in the upper surface 904 of the plate-like work 90 on the +Y direction side of the upper surface 904 of the plate-like work 90 . It is formed in the -Y direction from the beginning. As a result, for example, as shown in FIGS. 5 and 6 , a plurality of circular arcs are formed on substantially the entire surface of the upper surface 904 of the plate-like work 90 at substantially equal intervals in the traveling direction (Y-axis direction) of the plate-like work 90 . A groove 907 is formed.

Then, the curvature of the plate-like work 90 is corrected by the plurality of arcuate grooves 907, and the grinding wheel 1642 is kept in contact with the upper surface 904 of the plate-like work 90 sucked and held by the holding surface 302, so that the chuck table is rotated. 3, the frictional force acting between the grinding wheel 1642 and the upper surface 904 of the plate-like work 90 restores the curvature of the plate-like work 90 during grinding. , the occurrence of vacuum leaks and the like is eliminated.

(1-2) Embodiment 2 of Arc Groove Forming Step
For example, instead of the arcuate groove forming step of Embodiment 1, the arcuate groove forming step of Embodiment 2 described below may be carried out.
In the arc groove forming step of the second embodiment, for example, the inclination of the holding surface 302 of the chuck table 3 with respect to the lower surface of the grinding wheel 1642 is changed relatively so that the holding surface 302 holds the lower surface of the grinding wheel 1642 from the outer peripheral angle. The upper surface 904 of the plate-like work 90 is cut. That is, the outer edge of the grinding wheel 1642 forms arcuate grooves.

Specifically, the inclination of the chuck table 3 is adjusted by the inclination adjustment unit 37 shown in FIG. 7, so that the traveling direction of the plate-like workpiece 90 sucked and held by the chuck table 3 with respect to the grinding wheel 1642 is set to the +Y direction. In this case, the entire chuck table 3 is tilted so that the front side (+Y direction side) of the chuck table 3 is lower than the rear side (−Y direction side) of the chuck table 3 .

Next, the grinding unit 16 is moved in the X-axis direction by the X-axis movement unit 18 shown in FIG. The alignment of the grinding unit 16 and the chuck table 3 in the X-axis direction is performed so that the area on the −X direction side (back side of the paper surface) of the upper surface 904 of the plate-like workpiece 90 sucked and held by the holding surface 302 is positioned. done.

The upper surface 904 of the plate-like workpiece 90 sucked and held by the chuck table 3 that is step-moved in the +Y direction by the horizontal movement unit 13 is positioned below the grinding wheel 1642 of the grinding unit 16, Movement of the chuck table 3 stops once. Then, when the grinding unit 16 descends in the −Z direction at a predetermined grinding feed rate, the grinding wheel 1642 rotating at a predetermined rotational speed cuts into the upper surface 904 of the plate-like workpiece 90 . At this time, in this embodiment, the upper surface 904 of the plate-like workpiece 90 held by the holding surface 302 is cut from the outer peripheral angle (outer blade) of the lower surface of the grinding wheel 1642 . By not rotating the holding surface 302 of the chuck table 3, a single arcuate groove 908 shown in FIG.

After the grinding wheel 1642 cuts into the upper surface 904 from the outer blade to a position above the finished thickness of the plate-like workpiece 90 to form an arcuate groove 908 with a predetermined depth, the grinding wheel 1642 is raised. , is separated from the plate-like work 90 once.

(2-2) Grinding wheel moving process after the circular groove forming process of the second embodiment In order to position the grinding wheel 1642, the grinding wheel 1642 and the chuck table 3 are relatively moved horizontally. For example, by stepping the chuck table 3 by a predetermined distance in the +Y direction using the horizontal movement unit 13 shown in FIG. A grinding wheel 1642 of the grinding unit 16 is positioned above the area where the groove 908 has not yet been formed.

(3-2) Multiple Groove Forming Step of Repeating the Circular Groove Forming Step and the Grinding Wheel Moving Step of Embodiment 2 After the grinding wheel 1642 is newly positioned in the Y-axis direction, the grinding unit 16 is moved to Descending in the -Z direction at the grinding feed rate, the rotating grinding wheel 1642 cuts into the upper surface 904 of the plate-like workpiece 90 to a predetermined depth from the outer blade on the lower surface, forming the second arcuate groove 908 shown in FIG. be done. Then, a grinding wheel moving step similar to that described above is performed. In this way, by repeating the arcuate groove forming process and the grinding wheel moving process, a plurality of arcuate grooves 908 are formed in substantially the entire region of the upper surface 904 of the plate-like workpiece 90 on the -X direction side. are sequentially formed from the beginning toward the -Y direction side.

For example, a plurality of arcuate grooves 908 shown in FIG. 8 are sequentially formed from the +Y direction side to the −Y direction side in substantially the entire region of the −X direction side of the upper surface 904 of the plate-shaped workpiece 90, and then, as shown in FIG. The grinding unit 16 is moved in the +X direction by the X-axis movement unit 18 shown, and the plate-like work sucked and held on the holding surface 302 is placed on a straight line extending in the virtual Y-axis direction passing through the center of the grinding wheel 164. The grinding unit 16 and chuck table 3 are aligned in the X-axis direction so that the +X-direction side of the upper surface 904 of 90 in which the groove 908 is not yet formed is positioned.

Then, by repeating the arcuate groove forming step and the grinding wheel moving step of the second embodiment described above, a plurality of arcuate grooves are formed in substantially the entire region on the −X direction side of the upper surface 904 of the plate-shaped work 90. 908 are sequentially formed from the +Y direction side toward the -Y direction side. In the present embodiment, since the curvature of the central region is smaller than both regions on the ±X direction sides of the upper surface 904 of the plate-like workpiece 90 in which the arcuate grooves 908 are formed, in the example shown in FIG. Although the multiple groove forming process is completed without the grooves 908 formed, a plurality of arcuate grooves 908 may also be formed in the central region of the top surface 904 as shown in FIG. Since the four corners of the plate-like work 90 are particularly curved, it is preferable that arc-shaped grooves 908 are formed in the four corners after the step of forming the plurality of grooves.
Also, the arcuate grooves 908 may be formed so that the arcuate grooves 908 intersect each other.
The curvature of the plate-like workpiece 90 is corrected by the plurality of arcuate grooves 908 .

(1-3) Embodiment 3 of Arc Groove Forming Step
For example, instead of the arcuate groove forming step of Embodiment 1, the arcuate groove forming step of Embodiment 3 described below may be performed.
In the arc groove forming step of the third embodiment, for example, the tilt of the chuck table 3 is adjusted by the tilt adjusting unit 37 shown in FIG. It becomes substantially parallel to the lower surface of the grinding wheel 1642 .
It also has a table rotation mechanism 33 that rotates the chuck table 3 around the center of the chuck table 3 .

Next, the horizontal movement unit 13 shown in FIG. 3 moves the chuck table 3 holding the plate-like workpiece 90 below the grinding unit 16, and the X-axis movement unit 18 moves the grinding unit 16 in the X-axis direction. Then, the grinding wheel 164 and the plate-like workpiece 90 are aligned. In this alignment, for example, the center of rotation of the grinding wheel 1642 is shifted horizontally by a predetermined distance from the center of the holding surface 302 of the chuck table 3 (that is, the center of the upper surface 904 of the plate-like workpiece 90).

After the alignment is performed, the grinding unit 16 descends at a predetermined grinding feed rate, and the rotating grinding wheel 1642 comes into contact with the upper surface 904 of the plate-like workpiece 90 . Then, the upper surface 904 of the plate-like workpiece 90 held by the holding surface 302 is cut from the lower surface (flat surface) of the grinding wheel 1642 . Further, by not rotating the holding surface 302 of the chuck table 3, a single arcuate groove 909 passing through the center of the upper surface 904 of the plate-shaped workpiece 90 and one of four corner regions or two corner regions is formed. be.

The grinding wheel 1642 cuts into the upper surface 904 to a predetermined height above the finish thickness of the plate-like workpiece 90 in the grinding process, and after forming the arcuate groove 909 of the predetermined depth shown in FIG. The unit 16 rises in the +Z direction, and the grinding wheel 1642 is once separated from the plate-like work 90 .

(2-3) Grinding wheel moving step after the arc groove forming step of the third embodiment Next, the table rotation mechanism 33 rotates the chuck table 3 by a predetermined angle and then stops the rotation, thereby forming the arc groove of the third embodiment. The grinding wheel 1642 is positioned at a position different from the position of the grinding wheel 1642 positioned with respect to the plate-like work 90 in the forming process. The positional movement of the plate-like work 90 with respect to the grinding wheel 1642 is such that the rotation locus of the grinding wheel 1642 forms at least one or two of the four corner regions of the upper surface 904 of the plate-like work 90 . It is made to pass through. Further, the grinding wheel 1642 may be positioned with respect to the plate-like work 90 so that the rotational locus of the grinding wheel 1642 passes through the center of the plate-like work 90 .

(3-3) Step of forming a plurality of grooves by repeating the step of forming arc grooves and the step of moving the grinding wheel of the third embodiment. After the grinding wheel 1642 is newly positioned on the upper surface 904 of the plate-like workpiece 90 , the grinding unit 16 descends again at a predetermined grinding feed rate so that the rotating grinding wheel 1642 is placed on the upper surface 904 of the plate-shaped workpiece 90 . A second arcuate groove 909 shown in FIG. 10 is formed by cutting from the lower surface to a predetermined depth.
Then, a grinding wheel moving step similar to that described above is performed. In this way, by repeating the arcuate groove forming step and the grinding wheel moving step of the third embodiment a plurality of times, the four corner regions of the upper surface 904 of the plate-like workpiece 90, that is, the regions with a higher degree of curvature, are formed. The groove 909 is formed so that the circular arc groove 909 passes intensively.
By completing the multiple groove forming process, the curvature of the plate-like workpiece 90 is corrected by the multiple arcuate grooves 909 .

(1-4) Embodiment 4 of Arc Groove Forming Step
For example, instead of the arcuate groove forming step of Embodiment 1, the arcuate groove forming step of Embodiment 4 described below may be performed.
In the arc groove forming step of the fourth embodiment, for example, the inclination of the holding surface 302 of the chuck table 3 relative to the lower surface of the grinding wheel 1642 having a diameter larger than at least the size of the plate-like workpiece 90 is changed relatively to the grinding wheel. The upper surface 904 of the plate-like workpiece 90 held by the holding surface 302 is cut from the inner peripheral corner of the lower surface of 1642 . That is, the inner edge of the grinding wheel 1642 forms arcuate grooves.

Specifically, the inclination of the chuck table 3 is adjusted by the inclination adjustment unit 37 shown in FIG. 11, so that the advancing direction of the plate-like workpiece 90 sucked and held by the chuck table 3 with respect to the grinding wheel 1642 is set to the +Y direction. In this case, the entire chuck table 3 is tilted so that the front side (+Y direction side) of the chuck table 3 is higher than the rear side (−Y direction side) of the chuck table 3 .

Next, the grinding unit 16 shown in FIG. 11 is moved in the X-axis direction so that the plate-like workpiece 90 on the holding surface 302 of the chuck table 3 is moved on a virtual straight line passing through the center of the grinding wheel 164 and extending in the Y-axis direction. The grinding unit 16 and the chuck table 3 are aligned in the X-axis direction so that the center of .

After that, the upper surface 904 of the plate-like workpiece 90 sucked and held on the chuck table 3 by the horizontal movement unit 13 is positioned, for example, in the +Y direction at the end region below the grinding wheel 1642 of the grinding unit 16, and is moved to the chuck table 3. Step movement stops once. Then, when the grinding unit 16 descends in the −Z direction at a predetermined grinding feed rate, the grinding wheel 1642 rotating at a predetermined rotational speed contacts the upper surface 904 of the plate-like workpiece 90 .

Then, the grinding wheel 1642 cuts into the upper surface 904 of the plate-shaped workpiece 90 held by the holding surface 302 from the inner circumferential angle (inner blade) side of the lower surface. Then, by not rotating the holding surface 302 of the chuck table 3, as shown in FIG. 12, one circular arc groove 906 is formed in both regions of the upper surface 904 of the plate-like work 90 on the ±X direction side. At this time, since the grinding wheel 1642 does not contact the center region in the X-axis direction of the upper surface 904 of the plate-like work 90, the arcuate groove 906 is not formed in the center region.

After the grinding wheel 1642 cuts into the upper surface 904 from the inner blade side to a position above the finished thickness of the plate-like workpiece 90 to form an arcuate groove 906 with a predetermined depth, the grinding wheel 1642 is lifted. to move away from the plate-like work 90 once.

(2-4) Grinding wheel moving process after the arc groove forming process of the fourth embodiment The grinding wheel 1642 is relatively moved horizontally. Specifically, the chuck table 3 is stepped in the +Y direction by a predetermined distance, and the grinding unit is moved above the regions where the grooves 906 have not yet been formed in both regions on the ±X direction sides of the upper surface 904 of the plate-like workpiece 90 . Sixteen grinding wheels 1642 are positioned.

(3-4) A plurality of groove forming process in which the circular arc groove forming process and the grinding wheel moving process of Embodiment 4 are repeated. A second arcuate groove 906 is formed in both regions of the upper surface 904 on the ±X direction side by cutting the upper surface 904 of the upper surface 90 to a predetermined depth from the inner peripheral corner side of the lower surface. After that, the same grinding wheel moving step as before is performed. In this way, by repeating the arcuate groove forming step and the grinding wheel moving step of the fourth embodiment, a plurality of arcuate grooves 906 are formed in both regions of the upper surface 904 of the plate-like work 90 on the ±X direction side. The layers are sequentially formed from the +Y direction side toward the -Y direction side.

After the step of forming the plurality of grooves, the plate-like workpiece 90 having a larger curvature on the outer peripheral side is in a state in which the curvature is corrected by the plurality of arcuate grooves 906 shown in FIG.
If the inner diameter of the grinding wheel 1642 is smaller than the length of the plate-like workpiece 90, the chuck table 3 is moved in the +Y direction by one span from the +Y direction to the -Y direction in the arcuate groove 906 as shown in FIG. After the grinding wheel 1642 has passed through the central region of the plate-like workpiece 90 in the Y-axis direction, it is not possible to form the entire regions of the upper surface 904 on the ±X-direction sides. Therefore, as shown in FIG. 13, arcuate grooves 9066 are formed in each half of the plate-like workpiece 90 . Such arcuate grooves 9066 bisect the chuck table 3 in the +Y direction with respect to one region that is bisected across the center of the upper surface 904 of the plate-like workpiece 90 in the Y-axis direction (moving direction of the chuck table 3). to form half arcuate grooves 9066 at equal intervals, then rotate the chuck table 3 by 180 degrees to form the remaining half arcuate grooves 9066 in substantially the entire area of the other area. Form while moving. Alternatively, after forming the half-arc groove 9066 , the remaining arc-shaped groove 9066 is formed by changing the inclination of the chuck table 3 .
Further, by performing the arc groove forming step, the grinding wheel moving step, and the multiple groove forming step of Embodiment 4, for example, the outer edge of the grinding wheel 1642 may be is not consumed.

(4-1) Grinding process for performing infeed grinding After the completion of the multiple groove forming process, the plurality of arc grooves 907 shown in FIG. The upper surface 904 of the groove 908, the plurality of arcuate grooves 909 shown in FIG. 10, or the plurality of arcuate grooves 906 shown in FIG. For example, the main grinding is infeed grinding.

For example, the inclination of the chuck table 3 is adjusted by the inclination adjustment unit 37 shown in FIGS. approximately parallel to the Next, the horizontal movement unit 13 moves the chuck table 3 sucking and holding the plate-like work 90 under the grinding unit 16, and the plate-like work 90 with the center of rotation of the grinding wheel 1642 sucked and held on the holding surface 302 is moved. Alignment is performed so that the rotation locus of the grinding wheel 1642 passes through the center of the plate-shaped work 90 by shifting a predetermined distance from the center of the upper surface 904 of the plate-like work 90 in the horizontal direction.

After the alignment is performed, the grinding unit 16 descends at a predetermined grinding feed rate, and the grinding wheel 1642 rotating at a predetermined rotational speed contacts the upper surface 904 of the plate-like workpiece 90 . Further, as the chuck table 3 rotates at a predetermined rotational speed, for example, in the same direction as the rotation direction of the grinding wheel 1642, the plate-like work 90 held on the holding surface 302 also rotates. The entire upper surface 904 of the workpiece 90 is ground.

5, a plurality of arc grooves 908 shown in FIG. 8, a plurality of arc grooves 909 shown in FIG. 10, and a plurality of arc grooves shown in FIG. 13 or a plurality of arcuate grooves 9066 shown in FIG. Therefore, the plate-shaped workpiece 90 is separated from the holding surface 302, and a vacuum leak does not occur.

While the thickness of the ground work 90 is being measured by the thickness measuring unit 104 shown in FIGS. 1 and 3, a plurality of arcuate grooves 907 shown in FIG. The plurality of arcuate grooves 908 shown in FIG. 8, the plurality of arcuate grooves 909 shown in FIG. 10, the arcuate grooves 906 shown in FIG. 12, or the plurality of arcuate grooves 9066 shown in FIG. An upper surface 904 of the workpiece 90 is formed into a flat surface. When the plate-like work 90 is ground to a desired thickness, the grinding unit 16 is lifted, the grinding wheel 1642 is separated from the plate-like work 90, and the grinding process is completed.

(4-2) Grinding process for performing creep feed grinding Instead of infeed grinding, a plurality of arcuate grooves 907 shown in FIG. 908, the plurality of arc grooves 909 shown in FIG. 10, the plurality of arc grooves 906 shown in FIG. 12, or the plurality of arc grooves 9066 shown in FIG. The workpiece 90 may be creep-feed ground to a predetermined thickness.

For example, first, the lifting unit 17 descends the grinding unit 16 until the height position of the lower surface of the grinding wheel 1642 reaches the desired thickness (finished thickness) of the plate-like workpiece 90 . 1 and 3 adjusts the inclination of the chuck table 3 so that the upper surface 904 of the plate-like work 90 sucked and held by the holding surface 302 is aligned with the lower surface of the grinding wheel 1642. approximately parallel to the

Then, while the grinding wheel 164 rotates at a predetermined rotational speed, the horizontal movement unit 13 shown in FIG. The upper surface 904 of the plate-like work 90 is ground mainly by the outer surface of the grinding wheel 1642 .

5, a plurality of arc grooves 908 shown in FIG. 8, a plurality of arc grooves 909 shown in FIG. 10, and a plurality of arc grooves shown in FIG. or a plurality of arcuate grooves 9066 shown in FIG. , the plate-like work 90 is not separated from the holding surface 302 and vacuum leaks are not caused.

A plurality of arcuate grooves 907 shown in FIG. 5, a plurality of arcuate grooves 908 shown in FIG. 8, a plurality of arcuate grooves 909 shown in FIG. 10, and an arcuate groove shown in FIG. 906 or a plurality of arcuate grooves 9066 shown in FIG. 13 are removed, and the upper surface 904 of the plate-like workpiece 90 is formed into a flat surface. Then, when the chuck table 3 moves to a predetermined position in the Y-axis direction where the grinding wheel 1642 finishes passing over the upper surface 904 of the plate-like work 90 , the entire upper surface 904 of the plate-like work 90 is ground by the grinding wheel 1642 . .

As described above, the upper surface 904 of the curved plate-shaped workpiece 90 having a force in the direction (+Z direction) in which the outer peripheral portion held by the holding surface 302 of the chuck table 3 separates from the holding surface 302 is ground by the ring-shaped grinding wheel 1642. In the method of grinding a plate-like work 90 according to the present invention, the chuck table 3 holds the plate-like work 90 on the holding surface 302, and the grinding wheel 1642 positioned above the plate-like work 90 held on the holding surface 302 is driven. A circular arc groove forming step in which the holding surface 302 is lowered in a direction perpendicular to the holding surface 302 and a grinding wheel 1642 is cut into the upper surface 904 of the plate-like workpiece 90 to form circular arc grooves without rotating the holding surface 302, and a circular arc groove forming step. At least one of the grinding wheel 1642 and the chuck table 3 is moved relatively parallel to the holding surface 302 in order to position the grinding wheel 1642 at a position different from the position of the grinding wheel 1642 positioned with respect to the plate-like work 90 in . A plurality of grooves are formed in the upper surface 904 of the plate-like work 90 by repeating a grinding wheel moving step of moving in a direction, an arc groove forming step, and a grinding wheel moving step to correct the curvature of the plate-like work 90 . By providing the groove forming step, before the plate-like work 90 is ground and thinned, a plurality of grooves are formed to reduce the force with which the plate-like work 90 separates from the holding surface 302. The upper surface 904 of the plate-like work 90 is ground to remove the grooves, and the plate-like work 90 is prevented from separating from the holding surface 302 to prevent the occurrence of vacuum leaks. can be ground to a thickness of Further, since the formation of a plurality of grooves and the grinding process are performed only with the grinding wheel 1642, the number of types of grinding wheels can be reduced, and there is no need to stock multiple types of grinding wheels in the grinding apparatus 1. become.

It goes without saying that the method of grinding a plate-like work according to the present invention is not limited to the above-described embodiments, and may be implemented in various forms within the technical scope of the invention. Also, the configuration of the grinding apparatus 1 shown in FIG. 1 used when carrying out the grinding method can be changed as appropriate within the range in which the effects of the present invention can be exhibited.

90: Plate-shaped work 904: Upper surface of plate-shaped work 902: Lower surface of plate-shaped work 9000: Protective tape 1: Grinding device 10: Device base 13: Horizontal movement unit 130: Ball screw 132: Motor 3: Chuck table 30: Porous part 302: Holding surface 31: Frame body 37: Inclination adjusting part 371: Piston rod 35: Chuck base 11: Column 17: Lifting unit 170: Ball screw 172: Motor 16: Grinding unit 160: Rotating shaft 162: Motor 164: Grinding wheel 1641 : Wheel base 1642: Grinding wheel 104: Thickness measuring part 4: Pressing mechanism 44: Pressing pad 41: Arm part 40: Lifting mechanism 45: Rotating shaft

Claims (5)

A method of grinding a plate-shaped work, in which the upper surface of a curved plate-shaped work having a force in a direction in which an outer peripheral portion held by a holding surface of a chuck table separates from the holding surface is ground with an annular grinding wheel,
The chuck table holds the plate-like work on the holding surface, lowers the grinding wheel positioned above the plate-like work held on the holding surface in a direction perpendicular to the holding surface, and an arc groove forming step of forming an arc groove by cutting the grinding wheel into the upper surface of the plate-shaped work without rotating the plate-like work;
At least one of the grinding wheel and the chuck table is relatively positioned so as to position the grinding wheel at a position different from the position of the grinding wheel positioned with respect to the plate-shaped work in the arc groove forming step. A grinding wheel moving step of moving in a direction parallel to the holding surface;
a plurality of groove forming step of repeating the arc groove forming step and the grinding wheel moving step to form a plurality of the grooves on the upper surface of the plate-like work to correct the curvature of the plate-like work;
A method of grinding a plate-like work, comprising: after forming a plurality of grooves, grinding the upper surface of the plate-like work to remove the grooves, and grinding the plate-like work to a predetermined thickness. In the grinding step, the chuck table is rotated around the center of the holding surface, and the grinding wheel passing through the center of rotation of the plate-like workpiece held on the rotating holding surface is moved in a direction perpendicular to the holding surface. 2. The method of grinding a plate-like work according to claim 1, wherein the plate-like work is ground while being lowered. In the grinding step, the lower surface of the grinding wheel is positioned outside the outer periphery of the plate-shaped work held on the holding surface and below the upper surface of the plate-shaped work, and the plate-shaped work and the grinding wheel are held together. 2. The method of grinding a plate-like work according to claim 1, wherein the plate-like work is ground by bringing the plate-like work relatively closer in a direction parallel to the surface. In the arcuate groove forming step, the inclination of the holding surface of the chuck table with respect to the lower surface of the grinding wheel is relatively changed, and the plate-like workpiece held by the holding surface is shifted from the outer peripheral angle of the lower surface of the grinding wheel. 4. The method of grinding a plate-like workpiece according to claim 1, claim 2, or claim 3, wherein the upper surface is cut. In the arc groove forming step, the inclination of the holding surface of the chuck table with respect to the lower surface of the grinding wheel is relatively changed, and the plate-like workpiece held by the holding surface from the inner peripheral angle of the lower surface of the grinding wheel. 4. The method of grinding a plate-like workpiece according to claim 1, claim 2, or claim 3, wherein the upper surface of the plate-like workpiece is cut.

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