JP6910723B2 - Grinding method - Google Patents

Description

The present invention relates to a grinding method for grinding a work piece having a warp.

A plurality of devices are provided on a plate-shaped substrate such as a package substrate or a semiconductor wafer. When the substrate is thinned and cut, individual thinned device chips are formed. In the step of thinning the device chip, a grinding device including a holding table for holding the substrate and a grinding unit for grinding the substrate is used. In the grinding device, the substrate held on the holding table is ground by the grinding unit. The upper surface of the holding table serves as a holding surface for holding the substrate.

When grinding the substrate, for example, a holding table having a holding surface in the shape of the side surface of a cone having a side surface having a very small gradient is used so that the ground substrate has a uniform thickness (patented). Reference 1). When the holding table is used, grinding burns that leave grinding marks on the surface to be ground of the substrate and damage to the substrate are suppressed.

The grinding unit includes a spindle substantially parallel to the vertical direction, a wheel mount arranged at the lower end of the spindle, and a grinding wheel mounted on the lower surface of the wheel mount. Grinding wheels are arranged on the lower surface of the grinding wheel so as to line up along the outer circumference.

When grinding the substrate, for example, the spindle is rotated to rotate the grinding wheel and the holding table is rotated to move the grinding unit downward in the vertical direction. Then, when the grinding wheel mounted on the grinding wheel comes into contact with the substrate, the substrate is ground. The method of grinding the workpiece by lowering the machining unit arranged above the holding table in this way is called in-feed grinding.

For example, a porous member is arranged on the upper part of the holding table of the grinding device. The holding table has a suction path internally at one end leading to the porous member, and a suction source is connected to the other end of the suction path. When a work piece such as a substrate is placed on the porous member and the suction source is operated to apply a negative pressure to the work piece through the suction path and the porous member, the work piece is released. It is sucked and held on the holding table.

Japanese Unexamined Patent Publication No. 2000-288881

For example, a package substrate containing a plurality of devices covered with resin may warp in a valley shape with the side on which the resin is formed inside. In order to grind the resin using the package substrate having a valley-shaped warp as a work piece, when the package substrate is placed on the holding surface so as to expose the resin upward, the holding surface and the package are placed. A gap is created between the substrate and the substrate.

In order to properly suck and hold the work piece on the holding surface, a negative pressure must be appropriately applied to the work piece. However, if such a gap is generated between the holding surface and the workpiece, negative pressure leaks from the gap and suction holding becomes difficult. Grinding cannot be performed properly unless the work piece can be properly attracted and held.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a grinding method capable of appropriately suctioning and holding a work piece having a warp and grinding it.

According to one aspect of the present invention, it is a grinding method for grinding a work piece having a valley-shaped warp, and is a detection step for detecting the shape of the work piece to be ground and a work piece detected in the detection step. A grinding wheel whose rotation axis is tilted by a predetermined angle from the vertical direction based on the shape of the workpiece is rotated and positioned at a predetermined height position, and a holding table having a holding surface for holding the workpiece is the grinding wheel. By moving the holding surface from the outer peripheral side of the grinding wheel in a direction relatively parallel to the holding surface so as to pass directly under the grinding wheel, the holding surface is ground by the grinding wheel to form a valley-shaped curved shape on the holding surface. After performing the holding surface grinding step and the holding surface grinding step, the work piece is placed on the holding surface so as to match the shape of the work piece with the curved shape of the holding surface formed. A holding step of sucking and holding the workpiece on the holding table, and after performing the holding step, the grinding wheel whose rotation axis is tilted from the vertical direction based on the shape of the workpiece detected in the detection step. The holding table, which is rotated and positioned at a predetermined height position and holds the workpiece, is relatively held in the holding surface grinding step so as to pass directly under the grinding wheel from the outer peripheral side of the grinding wheel. Provided is a grinding method comprising a grinding step for grinding a workpiece by moving the table in a direction along the moving direction of the table.

Further, according to another aspect of the present invention, it is a grinding method for grinding a work piece having a valley-shaped warp, in which a detection step for detecting the shape of the work piece to be ground and the detection step are used. Based on the detected shape of the work piece, the holding surface grinding wheel whose rotation axis is tilted by a predetermined angle from the vertical direction is rotated and positioned at a predetermined height position to hold the work piece. By moving the holding table from the outer peripheral side of the holding surface grinding wheel in a direction relatively parallel to the holding surface so as to pass directly under the holding surface grinding wheel, the holding surface grinding wheel can be used. After performing the holding surface grinding step of grinding the holding surface to form a valley-shaped curved shape on the holding surface and the holding surface grinding step, the shape of the workpiece is formed on the curved shape of the holding surface. The work piece is placed on the holding surface so as to be aligned with each other, and the work piece is sucked and held by the holding table, and after the holding step is performed, the work piece detected in the detection step is performed. The grinding wheel for the workpiece whose rotation axis is tilted from the vertical direction based on the shape is rotated and positioned at a predetermined height position, and the holding table holding the workpiece is used as the grinding wheel for the workpiece. Grinding step that grinds the workpiece by moving it relatively along the moving direction of the holding table in the holding surface grinding step so as to pass directly under the grinding wheel for the workpiece from the outer peripheral side of the And, a grinding method characterized by the provision of.

When the grinding wheel is tilted from the vertical direction and the holding table is relatively moved so as to pass under the rotating grinding wheel, the holding surface of the holding table is ground and the lowest point of the grinding wheel passes. A valley-shaped curved shape is formed in which the formed region becomes the valley bottom. In the grinding method according to one aspect of the present invention, the shape of the workpiece having a valley-shaped warp is detected, and the inclination of the grinding wheel is set based on the shape of the workpiece, so that the grinding wheel is formed on the holding surface. The valley-shaped curved shape formed becomes a shape close to the shape of the workpiece.

When the work piece is placed on the holding surface so that the shape of the work piece matches the shape of the holding surface, the gap between the holding surface and the work piece becomes extremely small. Then, when the work piece is to be sucked and held on the holding table, the negative pressure is unlikely to leak, so that the work piece is properly sucked and held on the holding table.

After that, the grinding wheel is tilted and rotated from the vertical direction in the same manner as when the holding surface is formed, and the holding table is relatively moved so as to pass under the grinding wheel. Is properly ground along the shape of the holding surface. The method of grinding the workpiece by relatively moving the holding table so as to pass under the grinding wheel in this way is called creep feed grinding.

Therefore, according to one aspect of the present invention, there is provided a grinding method capable of appropriately suctioning and holding a warped workpiece to grind it.

1 (A) is a plan view schematically showing the front surface side of the package substrate, FIG. 1 (B) is a plan view schematically showing the back surface side of the package substrate, and FIG. 1 (C) is a plan view schematically showing the back surface side of the package substrate. , Is a side view schematically showing the package substrate. It is a perspective view which shows typically the grinding apparatus. FIG. 3A is a side view schematically showing a detection step for detecting the shape of the front surface side of the package substrate, and FIG. 3B schematically shows a detection step for detecting the shape of the back surface side of the package substrate. It is a side view which shows. 4 (A) is a cross-sectional view schematically showing a holding surface grinding step, FIG. 4 (B) is a top view schematically showing a holding surface grinding step, and FIG. 4 (C) is a holding surface view. It is sectional drawing which shows typically the holding surface ground by the surface grinding step. FIG. 5A is a cross-sectional view schematically showing a holding step, and FIG. 5B is a cross-sectional view schematically showing a grinding step.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. The workpiece of the grinding method according to the present embodiment is, for example, a substrate made of a material such as silicon, SiC (silicon carbide), or other semiconductor, or a material such as sapphire, glass, or quartz. Alternatively, the workpiece is a package substrate in which the device is covered with resin.

For example, a line to be cut is set in the work piece in a grid pattern, and a device is provided in each region partitioned by the line to be cut. Individual thin device chips can be formed by grinding and thinning the workpiece on which the device is formed by the grinding method according to the present embodiment and cutting the workpiece along the planned cutting line.

Hereinafter, the present embodiment will be described by taking a case where the package substrate is a work piece as an example. FIG. 1A is a plan view schematically showing the front surface of the package substrate, and FIG. 1B is a plan view schematically showing the back surface of the package substrate. FIG. 1C is a side view schematically showing the package substrate. The package substrate 1 includes a metal frame 3 formed in a substantially rectangular shape in a plan view. The metal frame 3 is made of a metal such as 42 alloy (an alloy of iron and nickel) or copper.

As shown in FIG. 1B, a plurality of stages 5 are arranged on the back surface 1b side of the package substrate 1. Devices (not shown) such as ICs (Integrated Circuits) and LSIs (Large Scale Integration) are provided on the front side of the stages 5 (the surface 1a side of the package substrate 1) so as to overlap each stage 5. A resin 9 for sealing the device is disposed on the package substrate 1. The resin 9 is formed to have a predetermined thickness and protrudes from the metal frame 3 in the thickness direction. On each stage 5, the device is covered with resin 9.

A plurality of electrode pads 7 are arranged in a matrix around each stage 5. The front side of each electrode pad 7 is covered with the resin 9, and the back side is exposed. The electrode pad 7 is connected to each electrode of each device with a metal wire (not shown) or the like before the resin 9 is formed. The electrode pad 7 located between two adjacent devices is connected to the two adjacent devices. When the package substrate 1 is cut to form individual device chips, the electrode pads 7 are divided into electrode terminals of the respective device chips.

A marker 11 is formed on the back surface 1b side of the package substrate 1. The marker 11 is used as a mark for aligning the processing unit with a predetermined position when cutting the package substrate 1. When the resin 9 together with the electrode pad 7 is cut between the pair of markers 11, individual device chips are formed. That is, each row and column in which the plurality of electrode pads 7 are lined up is a line to be cut.

Next, a grinding device that grinds the package substrate 1 from the surface 1a side in order to form a thin device chip will be described with reference to FIG. FIG. 2 is a perspective view schematically showing an example of a grinding device.

An opening 4a is provided on the upper surface of the apparatus base 4 of the grinding apparatus 2. Inside the opening 4a, an X-axis moving table 8 on which a holding table 6 for sucking and holding the workpiece is placed on the upper surface is provided. The X-axis moving table 8 can be moved in the X-axis direction by an X-axis direction moving mechanism (not shown). In the X-axis moving table 8, the carry-in / out area 10 to which the workpiece is attached / detached on the holding table 6 by the X-axis direction moving mechanism and the workpiece to be suction-held on the holding table 6 are ground. It is positioned in the processing area 12 and.

A porous member having an upper surface corresponding to the planar shape of the workpiece is disposed on the upper surface of the holding table 6, and the upper surface of the porous member serves as a holding surface 6a for holding the workpiece. The holding table 6 is internally provided with a suction path 6b (see FIG. 4A and the like) having one end connected to the porous member and the other end connected to a suction source (not shown). When the suction source is operated, a negative pressure acts on the work piece placed on the holding surface 6a, and the work piece is sucked and held on the holding table 6. Also, the holding table 6 can rotate about an axis perpendicular to the holding surface 6a.

A grinding unit 14 for processing the workpiece is arranged above the processing region 12. A support portion 16 is erected on the rear side of the apparatus base 4, and the grinding unit 14 is supported by the support portion 16. A pair of Z-axis guide rails 18 extending in the Z-axis direction are provided on the front surface of the support portion 16, and a Z-axis moving plate 20 is slidably attached to each Z-axis guide rail 18.

A nut portion (not shown) is provided on the back surface side (rear surface side) of the Z-axis moving plate 20, and a Z-axis ball screw 22 parallel to the Z-axis guide rail 18 is screwed into the nut portion. ing. A Z-axis pulse motor 24 is connected to one end of the Z-axis ball screw 22. When the Z-axis ball screw 22 is rotated by the Z-axis pulse motor 24, the Z-axis moving plate 20 moves in the Z-axis direction along the Z-axis guide rail 18.

A grinding unit 14 for grinding the workpiece is fixed to the lower portion on the front surface side of the Z-axis moving plate 20. If the Z-axis moving plate 20 is moved in the Z-axis direction, the grinding unit 14 can be moved in the Z-axis direction.

The grinding unit 14 is provided on a spindle 28 rotated by a motor connected to the proximal end side, a grinding wheel 30 mounted on the tip end side of the spindle 28 and rotating according to the rotation of the spindle 28, and a lower surface of the grinding wheel 30. The grinding wheel 32 is provided. The motor is provided in the spindle housing 26.

The grinding unit 14 is connected to the wheel inclination changing mechanism 30a. The wheel tilt changing mechanism 30a has a function of tilting the spindle 28 of the grinding unit 14 and the grinding wheel 30 at a predetermined angle in an XZ plane (a plane including the X-axis direction and the Z-axis direction). For example, the initial state is a state in which the spindle 28 is along the Z axis (vertical direction), and the wheel tilt changing mechanism 30a tilts the spindle 28 toward the X axis direction.

At the time of grinding in the grinding apparatus 2, first, the workpiece is placed on the holding surface 6a of the holding table 6 located in the carry-in / out area 10, and the holding table 6 is sucked and held to hold the holding table 6 in the machining area 12. Move to. Next, the grinding unit 14 (spindle 28 and grinding wheel 30) is tilted at a predetermined angle from the vertical direction by the wheel tilt changing mechanism 30a, and the Z-axis moving plate 20 is moved in the Z-axis direction to determine the grinding wheel 30. Position at the height position of.

Then, the spindle 28 is rotated to rotate the grinding wheel 30, and the holding table 6 is moved to the support portion 16 side of the grinding device 2 along the X-axis direction so as to pass below the grinding wheel 30. When the lower end of the grinding wheel 32 comes into contact with the workpiece, the workpiece is ground. The method of grinding the workpiece by relatively moving the holding table 6 so as to pass under the grinding wheel 30 in this way is called creep feed grinding.

Here, when the lateral direction of the package substrate 1 is the first direction 1d and the longitudinal direction is the second direction 1c, as shown in FIG. 1C, the package substrate 1 is the first direction 1d. When viewed from the side surface side including, the surface 1a side may be inside and warped in a valley shape.

When the package substrate 1 has a warp, it is easy to appropriately suck and hold the package substrate 1 on the holding table 6 when the package substrate 1 is to be ground from the surface 1a side by the grinding apparatus 2 as a workpiece. is not it. When the warped package substrate 1 is placed on the holding table 6, a gap is generated between the holding surface 6a and the package substrate 1, so that negative pressure is generated even if the suction source of the holding table 6 is operated. It is from the leak from the gap.

Therefore, in the grinding method according to the present embodiment, creep feed grinding is performed on the holding surface 6a of the holding table 6 in advance, and the holding surface 6a is processed so as to have a shape that matches the warp of the package substrate 1. Hereinafter, the grinding method according to the present embodiment will be described.

In the grinding method according to the present embodiment, a detection step for detecting the shape of the workpiece to be ground is carried out. FIG. 3A is a side view schematically showing a detection step for detecting the shape of the surface 1a side of the package substrate 1 which is the workpiece, and FIG. 3B is the package substrate which is the workpiece. It is a side view which shows typically the detection step which detects the shape of the back surface 1b side of 1. The detection step is carried out by a distance measuring device 34 having a function of detecting the shape of the workpiece mounted on the mounting surface 36.

The mounting surface 36 is a flat surface, and an object to be measured whose shape is detected by the distance measuring device 34 is mounted on the mounting surface 36. The distance measuring device 34 is, for example, a laser distance measuring device. The distance measuring device 34 irradiates the object to be measured mounted on the mounting surface 36 with a laser beam, and detects the laser beam reflected by the object to be measured and reaches the distance measuring device 34. The distance from the distance measuring device 34 to the object to be measured can be measured based on the time from the start of irradiation of the laser beam until the laser beam reaches the distance measuring device 34.

The shape of the upper surface of the object to be measured can be detected by scanning the entire upper surface of the object to be measured with the laser beam and obtaining the height of each point on the upper surface (distance from the distance measuring device 34).

The distance measuring device may be a contact type height measuring gauge. When the distance measuring device is a contact type height measuring gauge, when the gauge head (not shown) arranged at the lower end of the distance measuring device is brought into contact with the upper surface of the object to be measured, the height of the contacted portion is adjusted. Can be measured.

The grinding device 2 may include a distance measuring device 34, in which case the detection step is performed by the grinding device 2. If the grinding device 2 does not include the distance measuring device 34, the detection step is performed outside the grinding device 2.

In the detection step, as shown in FIG. 3A, first, the package substrate 1 as a work piece is placed on the mounting surface 36 so that the back surface 1b side is directed downward and the front surface 1a is exposed upward. Then, the distance measuring device 34 is scanned above the package substrate 1, and the distance measuring device 34 detects the height of each point on the surface 1a of the package substrate 1. Then, the shape of the surface 1a of the package substrate 1 can be detected.

In the detection step, as shown in FIG. 3B, the package substrate 1 is placed on the mounting surface 36 so that the front surface 1b side is directed downward and the back surface 1b is exposed upward, and the distance measuring device 34 is used for the detection step. The shape of the back surface 1b of the package substrate 1 may be detected.

In the grinding method according to the present embodiment, the holding table 6 of the grinding device 2 is ground by the grinding wheel 30, and the holding surface 6a is formed with a valley-shaped curved shape close to the shape of the package substrate 1. To carry out. FIG. 4A is a cross-sectional view schematically showing the holding surface grinding step, and FIG. 4B is a top view schematically showing the holding surface grinding step.

In the holding step described later, the package substrate 1 is placed on the holding table 6. In the holding surface grinding step, a valley-shaped curved shape close to the shape of the package substrate 1 is formed on the holding surface 6a so that a gap is not formed between the package substrate 1 and the holding surface 6a in the holding step. Form.

In the holding surface grinding step, the grinding wheel 30 is tilted by a predetermined angle by the wheel tilt changing mechanism 30a based on the shape of the package substrate 1 detected in the detection step. That is, the spindle 28 is tilted from the vertical direction (Z-axis direction). Next, the grinding wheel 30 is positioned at a predetermined height position, and the spindle 28 is rotated to rotate the grinding wheel 30. Then, the holding table 6 is relatively moved in a direction parallel to the holding surface 6a (X-axis direction) so as to pass directly under the grinding wheel 30, and the holding surface 6a is ground.

FIG. 4C is a cross-sectional view schematically showing the holding surface 6a ground in the holding surface grinding step. When the holding surface 6a is ground with the spindle 28 tilted from the Z-axis direction (vertical direction), a valley-shaped curved shape having a valley bottom in the region where the lowest point of the grinding wheel has passed is formed on the holding surface 6a. NS. The curved shape formed is determined by the magnitude of the inclination of the spindle 28. Therefore, in the holding surface grinding step, the inclination angle of the spindle 28 is determined based on the shape of the package substrate 1 detected in the detection step.

When the shape of the back surface 1b side of the package substrate 1 is detected in the detection step, the inclination angle of the spindle 28 is calculated so as to form a valley-shaped curved shape close to the detected shape on the holding surface 6a. Further, in the package substrate 1 having a valley-shaped warp, the front surface 1a side is curved in the same manner as the back surface 1b side. Therefore, even when the shape of the surface 1a side of the package substrate 1 is detected in the detection step, the inclination angle of the spindle 28 is calculated so as to form a valley-shaped curved shape close to the detected shape on the holding surface 6a. can.

Next, the holding step of the grinding method according to the present embodiment will be described. FIG. 5A is a cross-sectional view schematically showing the holding step. In the holding step, the package substrate 1 as a work piece is placed on the holding surface 6a of the holding table 6 with the back surface 1b side facing downward and the front surface 1a side which is the surface to be ground exposed upward. .. At this time, the package substrate 1 is placed on the holding surface 6a so as to match the shape of the package substrate 1 with the valley-shaped curved shape of the holding surface 6a formed by the holding surface grinding step.

Next, the suction source (not shown) of the holding table 6 is operated to apply a negative pressure to the package substrate 1 through the suction passage 6b, and the package substrate 1 is sucked and held by the holding table 6. Since the gap between the back surface 1b of the package substrate 1 and the holding surface 6a is extremely small, the negative pressure does not leak and the package substrate 1 can be appropriately sucked and held.

Next, the grinding step of the grinding method according to the present embodiment will be described. FIG. 5B is a cross-sectional view schematically showing the grinding step. In the grinding step, the surface 1a side of the package substrate 1 is ground by the grinding wheel 30 based on the shape of the package substrate 1 detected in the detection step.

In the grinding step, the grinding wheel 30 is tilted by a predetermined angle by the wheel tilt changing mechanism 30a based on the shape of the package substrate 1 detected in the detection step. That is, the spindle 28 is tilted from the vertical direction (Z-axis direction). Next, the grinding wheel 30 is positioned at a predetermined height position, and the spindle 28 is rotated to rotate the grinding wheel 30. Then, the holding table 6 is relatively moved in a direction parallel to the holding surface 6a (X-axis direction) so as to pass directly under the grinding wheel 30, and the package substrate 1 is ground.

That is, in the grinding step, the grinding wheel 30 is tilted at the same angle as the holding surface grinding step. Further, in the holding surface grinding step, the grinding wheel 30 is positioned at a height position where the holding surface 6a can be ground. On the other hand, in the holding surface grinding step, the package substrate 1 sucked and held on the holding surface 6a is ground, and the grinding wheel 30 is positioned at a height position where it can be thinned to a predetermined thickness. When the grinding step is performed, the package substrate 1 having a valley-shaped warp is appropriately ground so as to have a substantially uniform thickness along the shape of the holding surface 6a over the entire area.

As described above, according to the grinding method according to the present embodiment, a work piece having a warp can be appropriately attracted and held for grinding.

The present invention is not limited to the description of the above embodiment, and can be implemented with various modifications. For example, in the above embodiment, the case where the grinding device 2 has one grinding unit 14 and one grinding wheel 30 grinds both the holding surface 6a of the holding table 6 and the package substrate 1 has been described. One aspect of the invention is not limited to this. For example, the grinding device used in the grinding method according to one aspect of the present invention may include two grinding units.

That is, the grinding device may include two grinding wheels, a holding surface grinding wheel that grinds the holding surface of the holding table, and a workpiece grinding wheel that grinds the workpiece. In this case, the holding surface grinding step is performed using the holding surface grinding wheel, and the grinding step is performed using the workpiece grinding wheel. By using the two grinding wheels, it is possible to properly use a grinding wheel suitable for grinding the holding surface and a grinding wheel suitable for grinding the workpiece.

Further, in the above embodiment, the case where the workpiece warps in a valley shape along the lateral direction has been described as an example, but the present invention is not limited to this. According to one aspect of the present invention, even when the work piece warps in a valley shape along the longitudinal direction, the holding surface of the holding table is ground by a grinding wheel according to the warp of the work piece. Grinding can be performed by properly holding the work piece on the holding table.

Further, when a plurality of similar workpieces are ground one after another, a detection step is performed on all the workpieces to grind the holding surface according to the shape of each workpiece. There is no need to carry out the steps. If the method for producing the plurality of workpieces is the same, the warpage of all the workpieces tends to be about the same.

Therefore, when the shape of the first work piece is detected in the detection step when grinding the plurality of work pieces, and the holding surface grinding step is performed based on the shape, the second and subsequent work pieces can also be processed. The holding table 6 can be appropriately sucked and held. That is, in the grinding method according to one aspect of the present invention, the workpiece related to the detection step and the holding surface grinding step and the workpiece related to the holding step and the grinding step are not the same workpiece. Also in this case, it is possible to appropriately hold the workpiece and perform grinding.

In addition, the structure, method, etc. according to the above-described embodiment can be appropriately modified and implemented as long as they do not deviate from the scope of the object of the present invention.

1 Package substrate 1a Front surface 1b Back surface 1c Second direction 1d First direction 3 Metal frame 5 Stage 7 Electrode pad 9 Resin 11 Marker 2 Grinding device 4 Equipment base 4a Opening 6 Chuck table 6a Holding surface 6b Suction path 8 X Axis movement table 10 Carry-in / out area 12 Machining area 14 Grinding unit 16 Support part 18 Z-axis guide rail 20 Z-axis movement plate 22 Z-axis ball screw 24 Z-axis pulse motor 26 Spindle housing 28 Spindle 28a Wheel mount 30 Grinding wheel 30a Wheel tilt Change mechanism 32 Grinding grindstone 34 Distance measuring instrument 36 Mounting surface

Claims (2)

It is a grinding method that grinds a workpiece with a valley-shaped warp.
A detection step that detects the shape of the workpiece to be ground,
Based on the shape of the workpiece detected in the detection step, the grinding wheel whose rotation axis is tilted by a predetermined angle from the vertical direction is rotated and positioned at a predetermined height position to provide a holding surface for holding the workpiece. By moving the holding table from the outer peripheral side of the grinding wheel in a direction relatively parallel to the holding surface so as to pass directly under the grinding wheel, the holding surface is ground by the grinding wheel and the holding surface is ground. With a holding surface grinding step that forms a valley-shaped curved shape,
After performing the holding surface grinding step, the work piece is placed on the holding surface so as to match the shape of the work piece with the curved shape of the formed holding surface, and the work piece is placed on the holding table. With the holding step of sucking and holding,
After performing the holding step, the grinding wheel whose rotation axis is tilted from the vertical direction is rotated and positioned at a predetermined height position based on the shape of the workpiece detected in the detection step, and the workpiece is processed. By moving the holding table holding an object from the outer peripheral side of the grinding wheel in a direction relatively along the moving direction of the holding table in the holding surface grinding step so as to pass directly under the grinding wheel. Grinding steps to grind the workpiece and
A grinding method characterized by being equipped with. It is a grinding method that grinds a workpiece with a valley-shaped warp.
A detection step that detects the shape of the workpiece to be ground,
Based on the shape of the workpiece detected in the detection step, the grinding wheel for the holding surface whose rotation axis is tilted by a predetermined angle from the vertical direction is rotated and positioned at a predetermined height position to hold the workpiece. For the holding surface, the holding table having the holding surface is moved in a direction relatively parallel to the holding surface so as to pass directly under the holding surface grinding wheel from the outer peripheral side of the holding surface grinding wheel. A holding surface grinding step of grinding the holding surface with a grinding wheel to form a valley-shaped curved shape on the holding surface,
After performing the holding surface grinding step, the work piece is placed on the holding surface so as to match the shape of the work piece with the curved shape of the formed holding surface, and the work piece is placed on the holding table. With the holding step of sucking and holding,
After performing the holding step, the grinding wheel for the workpiece whose rotation axis is tilted from the vertical direction is rotated and positioned at a predetermined height position based on the shape of the workpiece detected in the detection step. The holding table holding the workpiece is relatively placed in the holding surface grinding step so that the holding table passes directly under the grinding wheel for the workpiece from the outer peripheral side of the grinding wheel for the workpiece. A grinding step that grinds the workpiece by moving it in the direction along the moving direction,
A grinding method characterized by being equipped with.

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