JP2023076853A - Method for shaping chuck table and method for grinding workpiece - Google Patents

Abstract

A chuck table shaping method capable of appropriately shaping the entire holding surface compared to conventional methods is provided. A method for shaping a chuck table includes relatively moving the chuck table and the grinding unit so as to approach each other along the Z-axis direction, and grinding the holding surface side of the chuck table. A first shaping step of shaping the center side of the surface, a movement stopping step of stopping relative movement of the chuck table and the grinding unit along the Z-axis direction, and simultaneously with or after the movement stopping step. , while relatively moving the chuck table and the grinding unit so as to separate them along the Z-axis direction, move the chuck table and the grinding unit in the X-axis direction so as to separate the center of the holding surface from the center of the shaping wheel. and a second shaping step of shaping the outer edge side of the holding surface by relatively moving along and grinding the holding surface side of the chuck table. [Selection drawing] Fig. 6

Description

The present invention grinds the central region of a disk-shaped workpiece held by a chuck table, and provides the workpiece with a disk-shaped thin plate portion and an annular thick plate portion surrounding the thin plate portion. and a method of shaping a chuck table and a method of grinding a workpiece.

2. Description of the Related Art In order to realize small and lightweight device chips, there are increasing opportunities to thin wafers having devices such as integrated circuits provided on the front side thereof. For example, the front side of the wafer is held by a chuck table, and a grinding wheel to which a grinding wheel containing abrasive grains is fixed and the chuck table are mutually rotated to supply a liquid such as pure water to the wafer. This wafer is ground and thinned by pressing a whetstone against the back surface of the wafer.

By the way, when the wafer as a whole is thinned by the above-described method, the rigidity of the wafer is greatly reduced, making it difficult to handle the wafer in subsequent processes. Therefore, by grinding the central (inner) region of the wafer where the devices are provided and leaving the outer (outer) region without grinding, the rigidity of the wafer after grinding is maintained at a sufficient level. Techniques have been proposed (see Patent Document 1, for example).

In this technology, a grinding wheel containing a plurality of grinding wheels arranged in a circle with an outer diameter (outer edge diameter) smaller than the diameter of the wafer grinds the central region of the wafer to form a disk-shaped thin plate portion. and an annular thick plate portion surrounding the thin plate portion. On the other hand, if the rotation axis of the chuck table and the rotation axis of the grinding wheel are parallel to each other during this grinding, the surface of the wafer to be ground may be burned or deep grinding marks may be formed. I end up.

In order to solve these problems, when the wafer is ground by the technique described above, the rotation axis of the grinding wheel is tilted relative to the rotation axis of the chuck table. However, when the rotation axis of the grinding wheel is tilted relative to the rotation axis of the chuck table, generally, the lower surface (grinding surface) of the grinding stone of the grinding wheel and the chuck table that holds the wafer are separated from each other. The gap between the holding surface of the and the is not constant.

As a result, the thickness of the thin plate portion obtained by grinding the wafer also varies according to the distance between the lower surface of the grindstone for grinding and the holding surface of the chuck table. Therefore, the chuck table is shaped in advance by a shaping wheel having a rotation axis relatively inclined at the same angle with respect to the rotation axis of the chuck table so that the thickness of the entire thin plate portion is uniform. (See, for example, Patent Document 2).

Japanese Unexamined Patent Application Publication No. 2007-19461 Japanese Patent Application Laid-Open No. 2008-60470

However, since the grinding wheels of the grinding wheel are arranged in an annular shape with an outer diameter smaller than the diameter of the wafer, using a shaping wheel containing an annularly arranged shaping wheel with the same diameter does not always result in a chuck. The entire holding surface of the table cannot be shaped. For example, if such a shaping wheel is used to grind the chuck table in the same manner as the wafer, the outer edge side of the holding surface that holds the outer edge side region (thick plate portion) of the wafer cannot be appropriately shaped.

It is also conceivable to shape the entire holding surface of the chuck table using a shaping wheel having an annular array of shaping wheels of a diameter capable of grinding the entire holding surface. However, in that case, the shape of the grinding surface of the shaping wheel by the plurality of shaping whetstones does not match the shape of the grinding surface of the grinding wheel by the plurality of grinding wheels. It cannot be shaped into an appropriate shape that matches the shape of the surface.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a chuck table shaping method capable of appropriately shaping the entire holding surface as compared with the conventional method.

According to one aspect of the present invention, there is provided a chuck table having a circular holding surface capable of holding a disk-shaped workpiece, and a plurality of grinding surfaces in an annular first region having an outer diameter smaller than that of the workpiece. A grinding unit having a spindle on which a grinding wheel having a grindstone fixed thereto is mounted, and a first direction along the holding surface and a second direction perpendicular to the first direction and intersecting the holding surface. and a moving unit for relatively moving the chuck table and the grinding unit along a grinding apparatus that grinds the center side region of the workpiece, thereby separating the disk-shaped thin plate portion and the thin plate portion A method of shaping a chuck table applied when forming a surrounding annular thick plate portion on the workpiece, wherein a plurality of chuck table portions are formed in a second annular region having the same outer diameter as the first region of the grinding wheel. A shaping wheel mounting step of mounting a shaping wheel to the spindle of the grinding unit; and after the shaping wheel mounting step, mounting the shaping wheel on the holding surface. The chuck table and the chuck table such that a position in one direction is equal to a reference position in the first direction of the grinding wheel with respect to the holding surface when grinding the central region of the workpiece. a positional relationship adjusting step of adjusting a positional relationship with the grinding unit in the first direction; and after the positional relationship adjusting step, moving the chuck table and the grinding unit closer along the second direction. and grinding the holding surface side of the chuck table to shape the central side of the holding surface; after the first shaping step, the chuck table and the a movement stopping step of stopping relative movement along the second direction with respect to the grinding unit; and simultaneously with or after the movement stopping step, moving the chuck table and the grinding unit to the second direction. moving the chuck table and the grinding unit relative to each other along the first direction to move the center of the holding surface away from the center of the shaping wheel while moving the chuck table and the grinding unit away from each other along the first direction; and a second shaping step of shaping the outer edge side of the holding surface by moving and grinding the holding surface side of the chuck table.

According to another aspect of the present invention, there is provided a method of grinding a workpiece, including the chuck table shaping method described above, wherein after the second shaping step, the grinding wheel is mounted on the spindle of the grinding unit. After the second shaping step, a holding step of holding the workpiece on the holding surface of the chuck table; After the grinding wheel mounting step and the holding step, the After adjusting the positional relationship in the first direction between the chuck table and the grinding unit so that the grinding wheel is positioned at the reference position with respect to the holding surface, the chuck table and the grinding unit is relatively moved so as to approach along the second direction, and the center side of the workpiece is ground, so that the disk-shaped thin plate portion and the annular thick plate surrounding the thin plate portion forming a portion in the workpiece.

In a chuck table shaping method according to one aspect of the present invention, the chuck table and the grinding unit are relatively moved so as to approach each other along a second direction intersecting the holding surface. After shaping, while relatively moving the chuck table and the grinding unit so as to separate them along the second direction, move the chuck table and the grinding unit so that the center of the holding surface and the center of the shaping wheel are separated. Since the outer edge side of the holding surface is shaped by relatively moving along the first direction, a plurality of shaping wheels having the same diameter as the plurality of grinding wheels used for grinding the workpiece are arranged in an annular shape. A grindstone can be used to shape the entire holding surface.

Further, in the chuck table shaping method according to one aspect of the present invention, relative movement of the chuck table for shaping the center side of the holding surface and the grinding unit along the second direction is stopped, and the position of the chuck table is stopped. Since the shaping of the outer edge side of the holding surface can be started from this point, no step occurs in the boundary area between the center side of the holding surface and the outer edge side of the holding surface. Thus, according to the chuck table shaping method according to one aspect of the present invention, the entire holding surface can be shaped more appropriately than the conventional method.

FIG. 1 is a cross-sectional view schematically showing a grinding device. FIG. 2 is a side view schematically showing the grinding device. FIG. 3 is a plan view schematically showing the grinding device. FIG. 4 is a cross-sectional view schematically showing a grinding device equipped with a shaping wheel. FIG. 5 is a cross-sectional view schematically showing how the center side of the holding surface is shaped. FIG. 6 is a cross-sectional view schematically showing how the outer edge side of the holding surface is shaped. FIG. 7 is a perspective view schematically showing a workpiece and the like. FIG. 8 is a cross-sectional view schematically showing how the workpiece is ground. FIG. 9 is a cross-sectional view schematically showing a chuck table shaped by a chuck table shaping method according to a modification.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, an example of a grinding apparatus used in the method for grinding a workpiece according to this embodiment will be described. 1 is a cross-sectional view schematically showing the grinding device 2, FIG. 2 is a side view schematically showing the grinding device 2, and FIG. 3 is a plan view schematically showing the grinding device 2. . In addition, in FIG. 1, some components are represented by the side surface. Also, the X-axis direction, Y-axis direction, and Z-axis direction used in the following description are directions perpendicular to each other.

As shown in FIG. 1 and the like, the grinding device 2 includes a chuck table 4 configured to hold a disk-shaped workpiece. The chuck table 4 includes a disc-shaped (columnar) frame 6 made of, for example, ceramics. A concave portion 6b having a circular opening at the upper end is formed on the upper surface 6a side of the frame 6. As shown in FIG. A retainer plate 8 formed in the shape of a porous disk using ceramics or the like is fixed to the recess 6b.

The upper surface 8 a of the holding plate 8 forms a circular holding surface 4 a of the chuck table 4 together with the upper surface 6 a of the frame 6 . For example, the diameter D1 (FIG. 3) of the circular upper surface 8a of the holding plate 8 is equal to or smaller than the diameter of the workpiece to be ground, and the diameter D1 of the upper surface 6a of the frame 6 is The outer diameter (diameter of the outer edge) is larger than the diameter of the workpiece.

The lower surface side of the holding plate 8 is connected to a suction source (not shown) such as an ejector through a channel (not shown), a valve (not shown), and the like. Therefore, when the work piece or the like is brought into contact with the upper surface 8a of the holding plate 8, the valve is opened, and the negative pressure of the suction source is applied, the work piece or the like is sucked by the chuck table 4. FIG. That is, the workpiece or the like is held on the holding surface 4 a of the chuck table 4 .

A rotary drive source (not shown) such as a motor is connected to the lower portion of the frame 6 . As shown in FIG. 2, the chuck table 4 is rotated in the Z-axis direction (the center of the holding surface 4a) so that the center of the upper surface 8a of the holding plate 8 (the center of the holding surface 4a) becomes the center of rotation by the power generated by the rotary drive source. second direction) around the rotation axis Z1. Note that the rotation axis Z1 of the chuck table 4 may be along the Z-axis direction, and does not necessarily have to be parallel to the Z-axis direction. That is, the rotation axis Z1 may be slightly inclined with respect to the Z-axis direction.

The frame 6 is supported by, for example, a ball screw type chuck table moving mechanism (moving unit) (not shown), and the chuck table 4 is moved to the holding surface 4a by the power generated by this chuck table moving mechanism. move along the X-axis direction (first direction). Note that the holding surface 4a of the chuck table 4 only needs to be along the X-axis direction, and does not necessarily have to be parallel to the X-axis direction. That is, the holding surface 4a of the chuck table 4 may be slightly inclined with respect to the X-axis direction.

A grinding unit 10 is arranged above the chuck table 4 . Grinding unit 10 includes a cylindrical spindle housing (not shown). The spindle housing is supported by, for example, a ball screw type grinding unit moving mechanism (moving unit) (not shown), and the grinding unit 10 moves in the X-axis direction (first direction) and intersects the holding surface 4a (second direction).

A space inside the spindle housing accommodates a columnar spindle 12 . A disk-shaped mount 14 having a smaller diameter than the workpiece is fixed to the lower end of the spindle 12, for example. A plurality of holes (not shown) passing through the mount 14 in the thickness direction are formed in the outer edge of the mount 14, and a bolt (not shown) or the like is inserted into each hole.

A disk-shaped grinding wheel 16 having approximately the same diameter as the mount 14 is attached to the lower surface of the mount 14 by bolts or the like. That is, the grinding wheel 16 is attached to the spindle 12 via the mount 14 or the like. The grinding wheel 16 includes a disk-shaped wheel base 18 made of metal such as stainless steel or aluminum. The outer edge of the upper surface of the wheel base 18 is provided with threaded holes into which the above-described bolts and the like are inserted.

A plurality of grinding wheels 20 are fixed along the circumferential direction of the wheel base 18 in an annular first region having an outer diameter D2 (FIG. 3) smaller than the diameter of the workpiece on the lower surface of the wheel base 18. It is Each grinding wheel 20 has a structure in which, for example, abrasive grains made of diamond or the like are dispersed in a binder made of resin or the like, and is suitable for grinding a workpiece.

A rotational drive source (not shown) such as a motor is connected to the upper end side of the spindle 12 . As shown in FIG. 2, the grinding wheel 16 is driven by the power generated by this rotational drive source so that the center of rotation of the grinding wheel 16 is the center of rotation of the axis of the spindle 12 (the center of the grinding wheel 16). It rotates around the axis of rotation Z2 along the direction.

Note that the rotation axis Z2 of the grinding wheel 16 (the axis of the spindle 12) only needs to be along the Z-axis direction, and does not necessarily have to be parallel to the Z-axis direction. That is, the rotation axis Z2 may be slightly inclined with respect to the Z-axis direction. In this embodiment, the rotation axis Z1 of the chuck table 4 and the rotation axis Z2 of the grinding wheel 16 form an angle θ on the YZ plane.

Beside the grinding wheel 16 or inside the grinding wheel 16, there is a nozzle (not shown) configured to supply a grinding liquid (typically pure water) to the grinding wheel 20 or the like. ) is provided. Also, as shown in FIG. 1, a contact-type height sensor is provided near the grinding wheel 16 for measuring the height of the holding surface 4a, the height of the upper surface of the workpiece held by the chuck table 4, and the like. A measuring device 22 is provided. However, instead of the contact height gauge 22, a non-contact height gauge using a laser beam or the like may be provided.

In the chuck table shaping method according to the present embodiment, the holding surface 4a of the chuck table 4 is ground by grinding the holding surface 4a. Specifically, first, a shaping wheel suitable for shaping the chuck table 4 is attached to the spindle 12 of the grinding unit 10 (shaping wheel attachment step). FIG. 4 is a cross-sectional view schematically showing the grinding device 2 on which the shaping wheel 24 is mounted.

Shaping wheel 24 , like grinding wheel 16 , is shaped like a disk having approximately the same diameter as mount 14 . That is, the shaping wheel 24 includes a disk-shaped wheel base 26 made of metal such as stainless steel or aluminum. A threaded hole into which a bolt or the like is inserted is provided on the outer edge of the upper surface of the wheel base 26 .

A plurality of shaping grindstones 28 are fixed to an annular second region (not shown) on the lower surface of the wheel base 26 . The outer diameter of the annular second region is substantially equal to the outer diameter of the annular first region of the grinding wheel 16 . Each shaping grindstone 28 has, for example, a structure in which abrasive grains made of diamond or the like are dispersed in a binder made of resin or the like, and is suitable for grinding the chuck table 4 .

When mounting the shaping wheel 24 configured in this manner to the spindle 12 of the grinding unit 10, for example, the bolts or the like securing the grinding wheel 16 to the mount 14 are removed. Then, instead of the grinding wheel 16, the shaping wheel 24 described above is fixed to the mount 14 with bolts or the like.

As with the grinding wheel 16, the shaping wheel 24 attached to the spindle 12 also rotates at the point of intersection with the axis of the spindle 12 (the center of the shaping wheel 24) due to the power generated by the rotational drive source. , rotates around the rotation axis along the Z-axis direction. That is, in this embodiment, the rotation axis of the shaping wheel 24 substantially coincides with the rotation axis Z2 of the grinding wheel 16, and the rotation axis Z1 of the chuck table 4 and the rotation axis of the shaping wheel 24 are aligned. The angle formed on the YZ plane is also θ.

After the shaping wheel 24 is attached to the spindle 12, the position of the shaping wheel 24 in the X-axis direction with respect to the holding surface 4a is adjusted (positional relationship adjustment step). The object of the chuck table shaping method according to the present embodiment is to realize the holding surface 4a having a shape sufficiently close to the shape of the upper surface of the workpiece after grinding.

Therefore, here, the position of the shaping wheel 24 in the X-axis direction with respect to the holding surface 4a corresponds to the position of the grinding wheel 16 in the X-axis direction with respect to the holding surface 4a when grinding the central region of the workpiece. (reference position), the chuck table moving mechanism adjusts the position of the chuck table 4 with respect to the grinding unit 10 . That is, the positional relationship in the X-axis direction between the chuck table 4 and the grinding unit 10 is adjusted.

After the position of the shaping wheel 24 with respect to the holding surface 4a in the X-axis direction is adjusted, the center side of the holding surface 4a of the chuck table 4 is shaped by the shaping wheel 24 (first shaping step). FIG. 5 is a cross-sectional view schematically showing how the center side of the holding surface 4a is shaped. In this embodiment, the chuck table 4 and the shaping wheel 24 (spindle 12) rotate, and the grinding unit moving mechanism lowers the grinding unit 10 while the liquid is supplied from the nozzle.

That is, the chuck table 4 and the grinding unit 10 move relatively so as to approach each other along the Z-axis direction. The speed (movement speed) at which the chuck table 4 and the grinding unit 10 move relative to each other is adjusted within a range in which the shaping grindstone 28 can be pressed against the chuck table 4 with an appropriate pressure. As a result, the side of the holding surface 4a of the chuck table 4 is ground, and a curved surface 8b corresponding to the shape of the surface ground by the plurality of shaping grindstones 28 is formed. That is, the central side of the holding surface 4a is shaped.

When the grinding unit 10 is sufficiently lowered, the grinding unit moving mechanism stops moving the grinding unit 10 (movement stop step). Thereby, the curved surface 8b having a shape suitable for grinding the workpiece is realized. The timing for stopping the movement of the grinding unit 10 is adjusted, for example, according to the result of measurement of the height of the holding surface 4a (curved surface 8b) by the height measuring device 22, or the like.

Simultaneously with or after the movement of the grinding unit 10 is stopped, shaping of the outer edge side of the holding surface 4a of the chuck table 4 is started (second shaping step). In this embodiment, using the positional relationship between the chuck table 4 and the grinding unit 10 determined by stopping the relative movement along the Z-axis, the shaping grindstone 28 and the holding surface 4a are substantially aligned. Shaping of the outer edge side of the holding surface 4a is started from the state of contact with .

FIG. 6 is a cross-sectional view schematically showing how the outer edge side of the holding surface 4a is shaped. Specifically, for example, the chuck table 4 and the shaping wheel 24 (spindle 12) are rotated, and the grinding unit moving mechanism lifts the grinding unit 10 while the liquid is being supplied from the nozzle. At the same time, the chuck table moving mechanism moves the chuck table 4 along the X-axis direction so that the center of the holding surface 4a and the center of the shaping wheel 24 are separated from each other.

That is, while the chuck table 4 and the grinding unit 10 move relatively apart along the Z-axis direction, the center of the holding surface 4a and the center of the shaping wheel 24 are separated along the X-axis direction. The chuck table 4 and the grinding unit 10 move relatively along the X-axis direction. As a result, the outer edge side of the holding surface 4a is shaped, and the slopes 8c and 6c having shapes corresponding to the relative movement paths of the chuck table 4 and the grinding unit 10 are formed.

The relative movement speed (first movement speed) of the chuck table 4 and the grinding unit 10 along the X-axis direction and the relative movement speed of the chuck table 4 and the grinding unit 10 along the Z-axis direction The moving speed (second moving speed) is adjusted to a range in which no substantial step occurs in the boundary area between the center side and the outer edge side of the holding surface 4a.

In other words, the speed at which the chuck table 4 and the grinding unit 10 move relative to each other along the X-axis direction and the relative speed along the Z-axis direction are such that the slope 8c can be continuously connected to the curved surface 8b. The speed to move to and is adjusted. As a result, the holding surface 4a without a step (joint) due to steps is realized, and the accuracy of grinding the workpiece is enhanced.

As described above, in the chuck table shaping method according to the present embodiment, the chuck table 4 and the grinding unit 10 are moved relative to each other so as to approach each other along the Z-axis direction (second direction) intersecting the holding surface 4a. After the chuck table 4 and the grinding unit 10 are relatively moved apart along the Z-axis direction, the center of the holding surface 4a and the shaping surface 4a are aligned with each other. Since the chuck table 4 and the grinding unit 10 are relatively moved along the X-axis direction (first direction) so as to separate from the center of the wheel 24, the outer edge side of the holding surface 4a is shaped. The entire holding surface 4a can be shaped by using a plurality of circularly arranged shaping grindstones 28 having the same diameter as the plurality of grinding grindstones 20 used for grinding.

In addition, in the chuck table shaping method according to the present embodiment, relative movement along the Z-axis direction between the chuck table 4 and the grinding unit 10 for shaping the center side of the holding surface 4a is stopped. Since the shaping of the outer edge side of the holding surface 4a can be started from the position, a step does not occur in the boundary area between the center side of the holding surface 4a and the outer edge side of the holding surface 4a. As described above, according to the chuck table shaping method according to the present embodiment, the entire holding surface 4a can be shaped more appropriately than the conventional method.

After the entire holding surface 4a of the chuck table 4 is shaped by the chuck table shaping method according to the present embodiment, the chuck table 4 is used to grind the workpiece. FIG. 7 is a perspective view schematically showing the workpiece 11 and the like to be ground by the grinding method for the workpiece according to the present embodiment.

The workpiece 11 is typically a disk-shaped wafer made of a semiconductor such as silicon (Si). The surface 11a side of the workpiece 11 is partitioned into a plurality of small regions by a plurality of dividing lines (streets) 13 crossing each other, and a device 15 such as an IC (Integrated Circuit) is placed in each small region. formed. In the present embodiment, the central region of the workpiece 11 corresponding to the region (device region) where the device 15 is formed is ground from the back surface 11b side opposite to the front surface 11a.

In this embodiment, the workpiece 11 is a disk-shaped wafer made of a semiconductor such as silicon, but the material, shape, structure, size, etc. of the workpiece 11 are not limited. For example, a substrate or the like made of other materials such as semiconductors, ceramics, resins, and metals can be used as the workpiece 11 . Similarly, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the device 15 .

In this embodiment, a protective member 21 is attached to the surface 11a side of the workpiece 11 . The protective member 21 is typically a circular tape (film) having approximately the same diameter as the workpiece 11, a resin substrate, or a wafer of the same type or different type as the workpiece 11, or the like. An adhesive layer (not shown) that exhibits adhesion to the workpiece 11 is provided on the surface 21 a side of the protective member 21 .

Therefore, the protective member 21 is attached to the workpiece 11 by bringing the surface 21a side of the protective member 21 into close contact with the workpiece 11 . In this embodiment, as shown in FIG. 7, the protective member 21 is attached to the surface 11a of the workpiece 11 by bringing the surface 21a side of the protective member 21 into close contact with the surface 11a of the workpiece 11 . This reduces the impact applied to the device 15 on the front surface 11a side when the workpiece 11 is ground from the back surface 11b side.

In the method of grinding a workpiece according to the present embodiment, first, the grinding wheel 16 described above is attached to the spindle 12 of the grinding unit 10 (grinding wheel attaching step). Specifically, the bolts or the like fixing the shaping wheel 24 to the mount 14 are removed. Then, instead of the shaping wheel 24, the grinding wheel 16 described above is fixed to the mount 14 with bolts or the like.

Next, the workpiece 11 is held by the chuck table 4 (holding step). Specifically, for example, the workpiece 11 is placed on the chuck table 4 so that the rear surface 21b of the protective member 21 is in contact with the holding surface 4a of the chuck table 4 after being shaped. When the valve is opened in this state, the negative pressure of the suction source acts on the holding surface 4a, and the back surface 21b of the protective member 21 is sucked by the chuck table 4. As shown in FIG. That is, the workpiece 11 is held on the chuck table 4 so that the back surface 11b side is exposed upward through the protective member 21 attached to the front surface 11a side.

After the grinding wheel 16 is attached to the spindle 12 and the workpiece 11 is held by the chuck table 4, the workpiece 11 is ground by the grinding wheel 16 (grinding step). FIG. 8 is a cross-sectional view schematically showing how the workpiece 11 is ground by the grinding wheel 16. As shown in FIG.

Specifically, first, the chuck table moving mechanism adjusts the position of the chuck table 4 with respect to the grinding unit 10 so that the grinding wheel 16 is positioned at the reference position with respect to the holding surface 4a. That is, the positional relationship in the X-axis direction between the chuck table 4 and the grinding unit 10 is adjusted.

After the positional relationship in the X-axis direction between the chuck table 4 and the grinding unit 10 is adjusted, the central side of the workpiece 11 is ground by the grinding wheel 16 . In this embodiment, the chuck table 4 and the grinding wheel 16 (spindle 12) rotate, and the grinding unit moving mechanism lowers the grinding unit 10 while the liquid is supplied from the nozzle.

That is, the chuck table 4 and the grinding unit 10 move relatively so as to approach each other along the Z-axis direction. The speed (moving speed) at which the chuck table 4 and the grinding unit 10 move relative to each other is adjusted within a range in which the grinding wheel 20 can be pressed against the workpiece 11 with an appropriate pressure.

As a result, the central region of the workpiece 11 is ground from the back surface 11b side, and as shown in FIG. and an annular thick plate portion 11d are formed on the workpiece 11. The shape of the upper surface (surface to be ground) of the obtained thin plate portion 11c is very close to the shape of the holding surface 4a.

As described above, in the method for grinding a workpiece according to the present embodiment, the chuck table 4 shaped by the chuck table shaping method described above is used, so that the shape of the upper surface (surface to be ground) of the thin plate portion 11c , and the shape of the holding surface 4a sufficiently close, the thickness of the thin plate portion 11c can be made substantially uniform over a wide range.

In the method for grinding a workpiece according to the present embodiment, the workpiece 11 is held by the chuck table 4 after the grinding wheel 16 is attached to the spindle 12. After 11 is held, grinding wheel 16 may be mounted on spindle 12 .

In the chuck table shaping method according to the present embodiment, when the outer edge side of the holding surface 4a is shaped, the entire upper surface 6a of the frame 6 is ground. (the portion that will become the thick plate portion 11d) may be shaped. That is, the upper surface 6a of the frame 6 does not necessarily have to be ground.

FIG. 9 is a cross-sectional view schematically showing the chuck table 4 shaped by the chuck table shaping method according to the modification. In the chuck table shaping method according to this modified example, the inner portion of the upper surface 6a of the frame 6 is ground to form an inclined surface 6c as shown in FIG. That is, in the chuck table 4 shaped according to the modified example, the outer portion of the upper surface 6a of the frame 6 remains without being removed. Of course, the upper surface 6a of the frame 6 may remain as it is without being ground at all.

In this modification, the relative movement speed (first movement speed) of the chuck table 4 and the grinding unit 10 along the X-axis direction and the relative movement speed of the chuck table 4 and the grinding unit 10 along the Z-axis direction The outer edge side of the holding surface 4a is shaped under a condition in which the ratio between the relative moving speed (second moving speed) and the ratio is different from that in the above-described embodiment. Specifically, for example, the first moving speed and the second moving speed are set such that the value obtained by dividing the second moving speed by the first moving speed is larger than in the above-described embodiment.

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

2: Grinding device 4: Chuck table 4a: Holding surface 6: Frame body 6a: Upper surface 6b: Recess 6c: Inclined surface 8: Holding plate 8a: Upper surface 8b: Curved surface 8c: Slanted surface 10: Grinding unit 12: Spindle 14: Mount 16: Grinding wheel 18 : Wheel base 20 : Grinding wheel 22 : Height measuring instrument 24 : Shaping wheel 26 : Wheel base 28 : Shaping wheel 11 : Workpiece 11a : Front surface 11b : Back surface 11c : Thin plate portion 11d : Thick plate part 13 : Line to be divided (street)
15: Device 21: Protective member 21a: Front surface 21b: Back surface D1: Diameter D2: Outer diameter Z1: Axis of rotation Z2: Axis of rotation

Claims (2)

A chuck table having a circular holding surface capable of holding a disk-shaped workpiece, and a grinding wheel having a plurality of grinding wheels fixed to an annular first region having an outer diameter smaller than that of the workpiece. and the chuck table and the grinding along a first direction along the holding surface and a second direction perpendicular to the first direction and transverse to the holding surface. and a moving unit for relatively moving the unit, grinding the center side region of the workpiece by the grinding device to grind the disk-shaped thin plate portion and the annular thick plate portion surrounding the thin plate portion. A chuck table shaping method applied when forming a workpiece, comprising:
a shaping wheel mounting step of mounting, to the spindle of the grinding unit, a shaping wheel having a plurality of shaping grindstones fixed to an annular second region having an outer diameter equal to that of the first region of the grinding wheel; ,
After the shaping wheel mounting step, the position of the shaping wheel relative to the holding surface in the first direction is such that the grinding wheel relative to the holding surface when grinding the central region of the workpiece. a positional relationship adjusting step of adjusting the positional relationship in the first direction between the chuck table and the grinding unit so as to be equal to the reference position in the first direction of the
After the positional relationship adjusting step, by relatively moving the chuck table and the grinding unit so as to approach each other along the second direction and grinding the holding surface side of the chuck table, a first shaping step of shaping the central side of the holding surface;
a movement stop step of stopping relative movement of the chuck table and the grinding unit along the second direction after the first shaping step;
Simultaneously with the movement stopping step or after the movement stopping step, while relatively moving the chuck table and the grinding unit away along the second direction, By relatively moving the chuck table and the grinding unit along the first direction so as to separate the center of the wheel and grinding the holding surface side of the chuck table, the outer surface of the holding surface is ground. and a second shaping step of shaping the edge side. A grinding method for a workpiece including the chuck table shaping method according to claim 1,
a grinding wheel mounting step of mounting the grinding wheel on the spindle of the grinding unit after the second shaping step;
a holding step of holding the workpiece on the holding surface of the chuck table after the second shaping step;
positional relationship in the first direction between the chuck table and the grinding unit so as to position the grinding wheel at the reference position with respect to the holding surface after the grinding wheel mounting step and the holding step; is adjusted, the chuck table and the grinding unit are moved relatively so as to approach each other along the second direction, and the central side of the workpiece is ground by grinding the disk-shaped and a grinding step of forming the thin plate portion and the annular thick plate portion surrounding the thin plate portion on the work piece.

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