JP2019038044A - Grinding method - Google Patents

Abstract

To suitably suck and hold a work-piece having a warp and grind the same.SOLUTION: A grinding method for grinding a work-piece having a valley-shaped warp comprises: a detection step at which a shape of a work-piece to be ground is detected; a holding surface grinding step at which a grinding wheel, a rotation axis of which is inclined from a vertical direction by a prescribed angle on the basis of the shape of the work-piece, is rotated, a holding table having a holding surface is moved in a direction parallel to the holding surface thereby grinding the holding surface by grinding wheel and forming a valley-shaped curved shape on the holding surface; a holding step at which the work-piece is loaded on the holding surface of the holding table, and the work-piece is sucked and held by the holding table; and a grinding step at which the grinding wheel, the rotation axis of which is inclined from the vertical direction on the basis of the shape of the work-piece detected at the detection step, is rotated, and the holding table is moved along a movement direction of the holding table at the holding surface grinding step, thereby grinding the work-piece.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a grinding method for grinding a workpiece having warpage.

  A plate-like substrate such as a package substrate or a semiconductor wafer is provided with a plurality of devices. When the substrate is thinned and cut, individual thinned device chips are formed. In the process of thinning the device chip, a grinding apparatus including a holding table that holds the substrate and a grinding unit that grinds the substrate is used. In the grinding apparatus, 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 the substrate is ground, for example, a holding table having a holding surface in the shape of a conical side surface having a very small slope is used so that the ground substrate has a uniform thickness (patent) Reference 1). When the holding table is used, grinding burn in which grinding marks remain 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 disposed at the lower end of the spindle, and a grinding wheel mounted on the lower surface of the wheel mount. A grinding wheel is arranged on the lower surface of the grinding wheel so as to be aligned along the outer periphery.

  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. When the grinding wheel mounted on the grinding wheel comes into contact with the substrate, the substrate is ground. In this way, the technique of lowering the machining unit arranged above the holding table and grinding the workpiece is called in-feed grinding.

  For example, a porous member is disposed on the upper part of the holding table of the grinding apparatus. The holding table has a suction path with one end leading to the porous member, and a suction source is connected to the other end of the suction path. When a workpiece such as the substrate is placed on the porous member and the suction source is operated to apply a negative pressure to the workpiece through the suction path and the porous member, the workpiece is It is sucked and held on the holding table.

JP 2000-288888 A

  For example, a package substrate including 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 with the package substrate having a valley warp as a workpiece, the package substrate is placed on the holding surface so as to expose the resin upward, and the holding surface and the package A gap is generated between the substrate and the substrate.

  In order to suck and hold the workpiece appropriately on the holding surface, a negative pressure must be appropriately applied to the workpiece. However, if such a gap is generated between the holding surface and the workpiece, negative pressure leaks from the gap, making suction holding difficult. If the workpiece cannot be sucked and held properly, grinding cannot be performed properly.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a grinding method capable of appropriately holding and grinding a workpiece having warpage.

  According to one aspect of the present invention, there is provided a grinding method for grinding a workpiece having a valley-shaped warp, the detection step for detecting the shape of the workpiece to be ground, and the workpiece detected in the detection step. A grinding wheel having a holding surface for holding a workpiece is rotated by rotating a grinding wheel whose rotation axis is inclined at a predetermined angle from the vertical direction based on the shape of the workpiece, and holding the workpiece. The holding surface is ground with the grinding wheel to form a valley-like curved shape by moving the holding surface relatively in a direction parallel to the holding surface so as to pass directly below the grinding wheel A holding surface grinding step, and after the holding surface grinding step, the workpiece is placed on the holding surface so as to match the shape of the workpiece with the curved shape of the formed holding surface, Workpiece with holding table A holding step for sucking and holding, and after carrying out the holding step, the grinding wheel whose rotation axis is inclined from the vertical direction is rotated based on the shape of the workpiece detected in the detecting step and at a predetermined height The holding table holding the workpiece is positioned along the moving direction of the holding table in the holding surface grinding step relatively so as to pass the holding table from the outer peripheral side of the grinding wheel directly under the grinding wheel. And a grinding step of grinding the workpiece by moving in a direction.

  Further, according to another aspect of the present invention, there is provided a grinding method for grinding a workpiece having a valley-like warp, wherein a detection step for detecting a shape of the workpiece to be ground, and the detection step The holding surface holding the workpiece is rotated by rotating the holding surface grinding wheel whose rotation axis is inclined at a predetermined angle from the vertical direction based on the detected shape of the workpiece and positioning the holding surface at a predetermined height position. The holding table is moved in the direction parallel to the holding surface relatively so as to pass from the outer peripheral side of the holding surface grinding wheel directly below the holding surface grinding wheel. A holding surface grinding step for grinding the holding surface to form a valley-like curved shape on the holding surface, and after performing the holding surface grinding step, the shape of the workpiece into the curved shape of the holding surface formed The workpiece to match A holding step for placing the workpiece on the holding surface and sucking and holding the workpiece by the holding table, and after performing the holding step, the rotation axis is set in the vertical direction based on the shape of the workpiece detected in the detecting step. The workpiece grinding wheel tilted from above is rotated and positioned at a predetermined height position, and the holding table holding the workpiece is moved from the outer peripheral side of the workpiece grinding wheel to the workpiece. A grinding step of grinding the workpiece by moving the holding table relatively in a direction along the moving direction of the holding table in the holding surface grinding step so as to pass directly under the grinding wheel. A grinding method is provided.

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

  When the workpiece is placed on the holding surface so that the shape of the workpiece matches the shape of the holding surface, the gap between the holding surface and the workpiece is extremely small. Then, since the negative pressure is unlikely to leak when the workpiece is sucked and held by the holding table, the workpiece is appropriately sucked and held by the holding table.

  After that, when the holding surface is formed, the grinding wheel is inclined and rotated from the vertical direction, and the holding table is relatively moved so as to pass below the grinding wheel. Is properly ground along the shape of the holding surface. Note that the method of grinding the workpiece by relatively moving the holding table so as to pass below the grinding wheel is called creep feed grinding.

  Therefore, according to one aspect of the present invention, there is provided a grinding method capable of appropriately holding and grinding a workpiece having warpage.

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

  Embodiments 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 a device is covered with a resin.

  In the workpiece, for example, scheduled cutting lines are set in a lattice shape, and a device is provided in each region partitioned by the scheduled cutting lines. When the workpiece on which the device is formed is ground and thinned by the grinding method according to this embodiment, and the workpiece is cut along the planned cutting line, individual thin device chips can be formed.

  Hereinafter, the present embodiment will be described by taking as an example the case where the package substrate is a workpiece. 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 plan view. The metal frame 3 is made of, for example, 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 1 b side of the package substrate 1. On the front side of the stage 5 (the surface 1a side of the package substrate 1), devices (not shown) such as IC (Integrated Circuit) and LSI (Large Scale Integration) are provided so as to overlap each stage 5. The package substrate 1 is provided with a resin 9 for sealing the device. The resin 9 is formed to 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. Each electrode pad 7 is covered with a resin 9 on the front side, 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 at a position sandwiched 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 to become electrode terminals of the respective device chips.

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

  Next, a grinding apparatus for grinding 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 apparatus.

  An opening 4 a is provided on the upper surface of the device base 4 of the grinding device 2. In the opening 4a, there is provided an X-axis moving table 8 on which a holding table 6 for sucking and holding a workpiece is placed. The X-axis moving table 8 can be moved in the X-axis direction by an X-axis direction moving mechanism (not shown). The X-axis moving table 8 includes a loading / unloading area 10 where a workpiece is attached to and detached from the holding table 6 by the X-axis direction moving mechanism, and a workpiece which is sucked and held on the holding table 6 is ground. And the processing region 12 to be positioned.

  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 includes a suction path 6b (see FIG. 4A, etc.) having one end communicating with 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 workpiece placed on the holding surface 6a, and the workpiece is sucked and held by the holding table 6. The holding table 6 can be rotated around an axis perpendicular to the holding surface 6a.

  A grinding unit 14 for processing the workpiece is disposed 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 that performs grinding of the workpiece is fixed to the lower part on the front 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 includes a spindle 28 that is rotated by a motor connected to the base end side, a grinding wheel 30 that is attached to the distal end side of the spindle 28 and rotates according to the rotation of the spindle 28, and a lower surface of the grinding wheel 30. A ground grinding wheel 32. The motor is provided in the spindle housing 26.

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

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

  Then, the spindle 28 is rotated to rotate the grinding wheel 30, and the holding table 6 is moved to the support unit 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. A method of grinding the workpiece by relatively moving the holding table 6 so as to pass below the grinding wheel 30 is called creep feed grinding.

  Here, when the shorter direction of the package substrate 1 is the first direction 1d and the longer direction is the second direction 1c, as shown in FIG. 1C, the package substrate 1 has the first direction 1d. May be warped in a valley shape with the surface 1a side as the inner side when viewed from the side including the surface.

  When the package substrate 1 is warped, it is easy to appropriately hold the package substrate 1 by the holding table 6 when the package substrate 1 is to be ground from the surface 1a side by the grinding device 2 as a workpiece. is not. When the package substrate 1 having warpage is placed on the holding table 6, a gap is generated between the holding surface 6 a and the package substrate 1, so that a negative pressure is generated even if the suction source of the holding table 6 is operated. It is from a 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 to process the holding surface 6a into 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 of detecting the shape of the workpiece to be ground is performed. 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 a workpiece, and FIG. 3B is a package substrate which is the workpiece. It is a side view which shows typically the detection step which detects the shape of 1 back side 1b side. The detection step is performed by the distance measuring device 34 having a function of detecting the shape of the workpiece placed on the placement surface 36.

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

  The shape of the upper surface of the object to be measured can be detected by scanning the laser beam over the entire upper surface of the object to be measured 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 a 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 increased. It can be measured.

  The grinding device 2 may have a distance measuring device 34, in which case the detection step is performed by the grinding device 2. When 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 workpiece is placed on the placement surface 36 so that the back surface 1b 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 height of each point on the surface 1 a of the package substrate 1 is detected by the distance measuring device 34. 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 placement 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 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 surface grinding step of grinding the holding table 6 of the grinding apparatus 2 with the grinding wheel 30 to form a valley-like curved shape close to the shape of the package substrate 1 on the holding surface 6a. To implement. FIG. 4A is a 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-like curved shape close to the shape of the package substrate 1 is formed on the holding surface 6a so that no gap is generated 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 inclined from the vertical direction (Z-axis direction). Next, the grinding wheel 30 is positioned at a predetermined height, and the spindle 28 is rotated to rotate the grinding wheel 30. Then, the holding table 6 is relatively moved so as to pass directly under the grinding wheel 30 in a direction parallel to the holding surface 6a (X-axis direction) to grind the holding surface 6a.

  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-like curved shape is formed in the holding surface 6a with the bottom of the grinding wheel passing through the region. The The curved shape to be formed is determined by the magnitude of the inclination of the spindle 28. Therefore, in the holding surface grinding step, the tilt angle of the spindle 28 is determined based on the shape of the package substrate 1 detected in the detection step.

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

  Next, the holding step of the grinding method according to this embodiment will be described. FIG. 5A is a cross-sectional view schematically showing the holding step. In the holding step, the package substrate 1 that is a workpiece is placed on the holding surface 6a of the holding table 6 with the back surface 1b facing downward and the surface 1a that 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-like curved shape of the holding surface 6a formed by the holding surface grinding step.

  Next, a suction source (not shown) of the holding table 6 is operated to apply a negative pressure to the package substrate 1 through the suction path 6 b, 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 this 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 inclined from the vertical direction (Z-axis direction). Next, the grinding wheel 30 is positioned at a predetermined height, and the spindle 28 is rotated to rotate the grinding wheel 30. Then, the holding table 6 is relatively moved in the 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 inclined at the same angle as in the holding surface grinding step. In the holding surface grinding step, the grinding wheel 30 is positioned at a height 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-like warp is appropriately ground so as to have a substantially uniform thickness along the shape of the holding surface 6a over the entire region.

  As described above, according to the grinding method according to the present embodiment, a workpiece having warpage can be appropriately sucked and held for grinding.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above-described embodiment, the grinding apparatus 2 has one grinding unit 14, and the case where both the holding surface 6a of the holding table 6 and the package substrate 1 are ground by one grinding wheel 30 has been described. One embodiment of the invention is not limited to this. For example, the grinding apparatus used in the grinding method according to one aspect of the present invention may include two grinding units.

  In other words, the grinding apparatus may include two grinding wheels: a holding surface grinding wheel for grinding the holding surface of the holding table, and a workpiece grinding wheel for grinding 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 two grinding wheels, a grinding wheel suitable for grinding a holding surface and a grinding wheel suitable for grinding a workpiece can be used properly.

  In the above-described embodiment, the case where the workpiece warps in a valley shape along the short side 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 workpiece warps in a valley shape along the longitudinal direction, the holding surface of the holding table is ground with the grinding wheel in accordance with the warpage of the workpiece, Grinding can be performed with the workpiece properly held on the holding table.

  In addition, when grinding a plurality of similar workpieces one after another, a holding surface grinding is performed in which a detection step is performed on all the workpieces and the holding surface is ground according to the shape of each workpiece. There is no need to perform the steps. If the manufacturing methods of the plurality of workpieces are the same, the warpage of all the workpieces tends to be the same.

  Therefore, when the plurality of workpieces are ground, the shape of the first workpiece is detected in the detection step, and if the holding surface grinding step is performed based on the shape, the second and subsequent workpieces are also 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. In this case as well, there is an effect that grinding can be performed while appropriately holding the workpiece.

  In addition, the structure, method, and the like according to the above-described embodiment can be appropriately modified and implemented without departing from the scope of the object of the present invention.

DESCRIPTION OF SYMBOLS 1 Package board | substrate 1a Front surface 1b Back surface 1c 2nd direction 1d 1st direction 3 Metal frame 5 Stage 7 Electrode pad 9 Resin 11 Marker 2 Grinding device 4 Apparatus base 4a Opening 6 Chuck table 6a Holding surface 6b Suction path 8X Axis moving table 10 Loading / unloading area 12 Processing area 14 Grinding unit 16 Support section 18 Z axis guide rail 20 Z axis moving 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 wheel 34 Distance measuring device 36 Mounting surface

Claims (2)

A grinding method for grinding a workpiece having a valley warp,
A detection step for detecting the shape of the workpiece to be ground;
Based on the shape of the workpiece detected in the detection step, a grinding wheel having a rotation axis inclined at a predetermined angle from the vertical direction is rotated and positioned at a predetermined height to hold a holding surface for holding the workpiece. The holding surface is ground with the grinding wheel 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. Holding surface grinding step to form a valley-like curved shape in
After performing the holding surface grinding step, the workpiece is placed on the holding surface so as to match the shape of the workpiece with the curved shape of the formed holding surface, and the workpiece is placed on the holding table. A holding step for sucking and holding;
After carrying out the holding step, the grinding wheel having the rotation axis inclined from the vertical direction based on the shape of the workpiece detected in the detection step is rotated and positioned at a predetermined height position, and the workpiece is processed. The holding table holding the object is moved in the direction along the moving direction of the holding table in the holding surface grinding step so as to pass from the outer peripheral side of the grinding wheel directly below the grinding wheel. A grinding step for grinding the workpiece;
A grinding method characterized by comprising: A grinding method for grinding a workpiece having a valley warp,
A detection step for detecting the shape of the workpiece to be ground;
Based on the shape of the workpiece detected in the detection step, the holding surface grinding wheel whose rotation axis is inclined at a predetermined angle from the vertical direction is rotated and positioned at a predetermined height to hold the workpiece. By moving the holding table having the holding surface 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. A holding surface grinding step of grinding the holding surface with a grinding wheel to form a valley-like curved shape on the holding surface;
After performing the holding surface grinding step, the workpiece is placed on the holding surface so as to match the shape of the workpiece with the curved shape of the formed holding surface, and the workpiece is placed on the holding table. A holding step for sucking and holding;
After carrying out the holding step, the grinding wheel for the workpiece, whose rotation axis is inclined from the vertical direction, is rotated and positioned at a predetermined height based on the shape of the workpiece detected in the detection step. The holding table in the holding surface grinding step is relatively moved so that the holding table holding the workpiece passes from the outer peripheral side of the workpiece grinding wheel directly below the workpiece grinding wheel. A grinding step for grinding the workpiece by moving in a direction along the moving direction;
A grinding method characterized by comprising: