JP7455463B2 - cutting equipment - Google Patents

Description

The present invention relates to a cutting device for cutting a wafer having recesses.

In the manufacturing process of device chips, device regions are formed in which devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in multiple regions divided by dividing lines (street) arranged in a grid pattern. , and a peripheral surplus area surrounding the device area. By dividing this wafer along the planned dividing line, a plurality of device chips each having a device are obtained.

For example, a cutting device is used to divide the wafer. The cutting device includes a chuck table that holds the wafer, and a cutting unit that is equipped with an annular cutting blade that cuts the wafer. The wafer is cut and divided by rotating the cutting blade and cutting into the wafer.

Furthermore, in recent years, as electronic devices have become smaller, device chips have been required to be thinner. Therefore, processing to thin the wafer is sometimes performed before dividing the wafer. For thinning a wafer, for example, a grinding device is used that includes a chuck table that holds the wafer and a grinding unit that is equipped with a grinding wheel to which a plurality of grinding wheels are fixed. The wafer is ground and thinned by bringing the grinding wheel into contact with the back side of the wafer while rotating the chuck table and the grinding wheel.

However, when a wafer is thinned by grinding, its rigidity decreases, making it more susceptible to damage when it is subsequently handled (processed, cleaned, transported, etc.). As a result, a method has been proposed in which only the central portion of the back side of the wafer that overlaps with the device region is ground to thin it. With this method, the outer periphery of the wafer is not thinned and remains thick, suppressing the decrease in the rigidity of the wafer and preventing damage to the wafer.

When only the center portion of the wafer is ground as described above, a wafer is obtained that includes a recess formed on the back side and an annular outer peripheral portion (convex portion) surrounding the recess. When the wafer is finally divided into a plurality of device chips, the outer peripheral portion of the wafer that has not been thinned is first removed using a cutting device or the like (see, for example, Patent Document 1).

When removing the outer periphery of a wafer using a cutting device, it is necessary to hold the wafer with the recessed portions on a chuck table. For example, a chuck table is formed by fitting a disc-shaped porous member into the center of the upper surface of a cylindrical frame (base), and holds the wafer between the upper surface of the outer periphery of the frame and the upper surface of the porous member. A holding surface is constructed.

When holding a wafer on the chuck table, the holding surface side of the chuck table is fitted into the recess of the wafer, and the recess of the wafer is held by the holding surface. Then, the central part of the recess of the wafer is sucked by the negative pressure of the suction source connected to the porous member, and the outer periphery of the recess of the wafer 11 is sucked by the upper surface of the outer peripheral part of the frame (the area where the porous member is not provided). part is supported.

When a wafer is held by the chuck table, the outer periphery of the recess of the wafer is supported by the upper surface of the outer periphery of the frame, but is not attracted. Therefore, when the outer periphery of the concave part of the wafer is cut in order to remove the outer periphery (convex part) of the wafer, in particular, when the outer periphery of the concave part of the wafer is not sufficiently fixed to the chuck table, A cutting blade rotating at high speed makes contact. As a result, vibration (shake) occurs at the outer periphery of the concave portion of the wafer, which may cause chipping or cracking of the wafer.

Therefore, a chuck table having a convex portion (cylindrical rising portion) corresponding to the concave portion of the wafer on the upper surface side is sometimes used to hold a wafer in which a concave portion is formed (see, for example, Patent Document 2). This chuck table is configured to be able to suck not only the central portion of the recessed portion of the wafer, but also the outer peripheral portion (convex portion) of the wafer surrounding the recessed portion. This securely fixes the entire wafer, making it difficult for the wafer to vibrate (shake) during cutting.

Japanese Patent Application Publication No. 2011-61137 JP2013-98248A

As described above, when processing a wafer that includes a recess and an annular outer circumferential portion surrounding the recess, a chuck table that has a convex portion on the upper surface side can be used. If there is a discrepancy between the depth of the concave part of the wafer and the amount of protrusion (height) of the convex part of the chuck table, the wafer will not make proper contact with the holding surface of the chuck table, and the chuck table will not be able to hold the wafer properly. Become complete. If the wafer is cut with a cutting blade in this state, processing defects are likely to occur on the wafer.

Therefore, when holding a wafer with a chuck table having a convex portion, it is necessary to precisely adjust the amount of protrusion of the convex portion of the chuck table in accordance with the depth of the concave portion of the wafer. However, since the depth of the concave portions differs from wafer to wafer, when changing the wafer to be processed, the amount of protrusion of the convex portions is changed each time. This complicates the preparation work for the chuck table and reduces wafer processing efficiency.

The present invention has been made in view of this problem, and an object of the present invention is to provide a cutting device equipped with a chuck table that can appropriately and easily hold a wafer having a recessed portion.

According to one aspect of the present invention, there is provided a cutting apparatus for cutting a wafer, comprising a recess formed in a central portion and an annular outer circumferential portion surrounding the recess, the holder for holding the recess of the wafer. The chuck table includes a chuck table having a surface, a cutting unit that cuts the wafer held by the chuck table with a cutting blade, and a suction source. A suction path that opens at the holding surface and is connected to the suction source is provided in an area that overlaps the outer periphery of the recess and corresponds to the processed area to be cut by the cutting blade, and the suction path is connected to the suction source of the chuck table. The chuck table includes a concentric first groove and a second groove provided on the holding surface side, and a flow path connecting the first groove and the second groove to the suction source. A cutting device is provided that supports the processed region of the wafer in a region between the first groove and the second groove and sucks the wafer between the first groove and the second groove .

Preferably , the first groove and the second groove are formed so that the width becomes narrower from the upper end to the lower end.

According to another aspect of the present invention, there is provided a cutting apparatus for cutting a wafer, including a recess formed in the center and an annular outer circumference surrounding the recess, the apparatus comprising: a chuck table having a holding surface for holding the wafer; a cutting unit for cutting the wafer held by the chuck table with a cutting blade; and a suction source. A suction path that opens at the holding surface and is connected to the suction source is provided in an area of the wafer that overlaps with the outer circumference of the recess and corresponds to the processed area to be cut by the cutting blade, and the suction path includes : The chuck table includes an annular suction area formed with unevenness on the holding surface side, and a flow path connecting the suction area and the suction source, and the chuck table has a convex portion of the suction area. A cutting device is provided which supports the processed area of the wafer and sucks the wafer with a recess in the suction area.

A cutting apparatus according to one aspect of the present invention includes a chuck table in which a suction path is provided in an area corresponding to a processed area of a wafer. This makes it possible for the cutting device to reliably fix the processing area of the wafer regardless of the depth of the recess of the wafer, and the wafer can be held appropriately and easily. Then, the vibration (shaking) of the wafer when the cutting blade comes into contact with the region to be processed is suppressed, and the occurrence of processing defects is prevented.

FIG. 1(A) is a perspective view showing the front side of the wafer, and FIG. 1(B) is a perspective view showing the back side of the wafer. FIG. 2 is a perspective view showing a wafer supported by a frame. It is a perspective view showing a cutting device. FIG. 4(A) is a plan view showing the chuck table, and FIG. 4(B) is an enlarged cross-sectional view showing the first groove and the second groove. FIG. 2 is a partially sectional front view showing a cutting device that cuts a wafer. FIG. 6(A) is a partially sectional front view showing a cutting device in which a suction area having unevenness is provided on a chuck table, and FIG. 6(B) is an enlarged sectional view showing the suction area.

Hereinafter, embodiments according to one aspect of the present invention will be described with reference to the accompanying drawings. First, a configuration example of a wafer that can be processed by the cutting apparatus according to the present embodiment will be described. 1(A) is a perspective view showing the front side of the wafer 11, and FIG. 1(B) is a perspective view showing the back side of the wafer 11.

The wafer 11 is a disk-shaped substrate made of, for example, silicon, and includes a front surface 11a and a back surface 11b that are substantially parallel to each other, and a side surface 11c connected to the front surface 11a and the back surface 11b. The wafer 11 is divided into a plurality of rectangular regions by a plurality of dividing lines (streets) 13 arranged in a grid so as to intersect with each other, and ICs and LSIs are respectively arranged on the surface 11a side of these regions. A device 15 such as the above is formed.

The wafer 11 includes, on the front surface 11a side, a substantially circular device region 17a in which a plurality of devices 15 are formed, and an annular peripheral surplus region 17b surrounding the device region 17a. The outer peripheral surplus region 17b corresponds to an annular region having a predetermined width (for example, about 2 mm) including the outer peripheral edge of the surface 11a. In FIG. 1A, the boundary between the device region 17a and the peripheral surplus region 17b is indicated by a two-dot chain line.

Note that there are no restrictions on the material, shape, structure, size, etc. of the wafer 11. For example, the wafer 11 may be a substrate made of a semiconductor other than silicon (GaAs, InP, GaN, SiC, etc.), glass, ceramics, resin, metal, or the like. Furthermore, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the device 15.

By dividing the wafer 11 into a lattice pattern along the planned division lines 13, a plurality of device chips each including a device 15 are manufactured. Note that by performing a thinning process on the wafer 11 before division, thinned device chips can be obtained.

For example, a grinding device is used to thin the wafer 11. The grinding device includes a chuck table (holding table) that holds the wafer 11, and a grinding unit to which a grinding wheel to which a plurality of grinding wheels are fixed is mounted. By bringing the grinding wheel into contact with the back surface 11b side of the wafer 11 while rotating the chuck table and the grinding wheel, the back surface 11b side of the wafer 11 is ground and the wafer 11 is thinned.

Here, the thinning process (grinding process) is performed only on the central portion of the back surface 11b side of the wafer 11. Therefore, as shown in FIG. 1B, only the central portion of the wafer 11 is thinned, and a circular recess 19 is formed in the central portion of the back surface 11b of the wafer 11. Note that the recess 19 is provided at a position corresponding to the device region 17a. For example, the size (diameter) of the recess 19 is set to be approximately the same as the size (diameter) of the device region 17a, and the recess 19 is formed at a position overlapping the device region 17a.

The recess 19 includes a bottom surface 19a that is generally parallel to the front surface 11a and the back surface 11b of the wafer 11, and an annular side surface (inner wall) 19b that is generally perpendicular to the bottom surface 19a and connected to the back surface 11b and the bottom surface 19a of the wafer 11. Further, around the recess 19, an outer peripheral part (convex part) 21 of the wafer 11 that has not been subjected to the thinning process (grinding process) remains, and the outer peripheral part 21 surrounds the recess 19.

If the entire back surface 11b side of the wafer 11 is ground, the entire wafer 11 will be thinned and the rigidity of the wafer 11 will decrease, and when handling the wafer 11 afterwards (processing, cleaning, transporting the wafer 11, etc.) ), the wafer is more likely to be damaged. On the other hand, when only the central portion of the wafer 11 is thinned as described above, the outer peripheral portion 21 of the wafer 11 is maintained in a thick state and a decrease in the rigidity of the wafer 11 is suppressed, so that the wafer 11 is less likely to be damaged. That is, the outer peripheral portion 21 of the wafer 11 that has not been thinned functions as a reinforcing region that reinforces the wafer 11.

The wafer 11 with the recesses 19 formed therein is finally cut along the dividing line 13 and divided into a plurality of device chips. When dividing the wafer 11, the wafer 11 is first supported by an annular frame. FIG. 2 is a perspective view showing the wafer 11 supported by an annular frame 25. As shown in FIG.

A tape 23 having a size that can cover the entire back surface 11b of the wafer 11 is attached to the back surface 11b side of the wafer 11. For example, a circular tape 23 having a larger diameter than the wafer 11 is attached to cover the back surface 11b of the wafer 11.

For example, as the tape 23, a flexible film including a circular base material and an adhesive layer (glue layer) provided on the base material is used. The base material is made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate, and the adhesive layer is made of an epoxy, acrylic, or rubber adhesive. Moreover, an ultraviolet curing resin that is cured by irradiation with ultraviolet light can also be used for the adhesive layer.

The tape 23 is attached along the shape of the back surface 11b of the wafer 11. Therefore, the tape 23 comes into close contact with the bottom surface 19a of the recess 19 and the outer circumference 21 (see FIG. 5). Note that the tape 23 may be attached so as to be in close contact with the side surface 19b of the recess 19, but a gap may be formed between the tape 23 and the side surface 19b of the recess 19 as shown in FIG. .

An annular frame 25 is attached to the outer periphery of the tape 23. The frame 25 includes a circular opening 25a in which the wafer 11 can be accommodated. The wafer 11 is supported by the frame 25 via the tape 23 while being placed inside the opening 25a.

The wafer 11 is cut by a cutting device while being supported by the frame 25. FIG. 3 is a perspective view showing the cutting device 2. As shown in FIG. The cutting device 2 includes a chuck table (holding table) 4 that holds a wafer 11, and a cutting unit 16 that cuts the wafer 11 held by the chuck table 4.

The chuck table 4 includes a cylindrical frame 6 made of metal such as SUS (stainless steel), glass, ceramics, resin, or the like. The upper surface of the frame 6 is formed into a circular shape that is generally parallel to the horizontal direction. The upper surface of the frame 6 constitutes a holding surface 4a of the chuck table 4, and the wafer 11 to be cut by the cutting device 2 is held on this holding surface 4a.

The chuck table 4 is provided with a suction path 8 for suctioning the wafer 11. One end side (upper end side) of the suction path 8 is open at the holding surface 4a of the chuck table 4, and the other end side (lower end side) of the suction path 8 is connected to a suction source (suction unit) 10 such as an ejector. There is. For example, the suction path 8 includes a first groove 12a and a second groove 12b formed on the holding surface 4a side of the chuck table 4, and a flow path 14 connecting the first groove 12a and the second groove 12b with the suction source 10. Equipped with

FIG. 4(A) is a plan view showing the chuck table 4. FIG. An annular first groove 12a and a second groove 12b are provided on the holding surface 4a side of the outer peripheral portion of the chuck table 4, and are formed at a predetermined depth from the holding surface 4a toward the lower side of the chuck table 4. ing. The diameter of the first groove 12a is larger than the diameter of the second groove 12b, and the centers of the first groove 12a and the second groove 12b are aligned. That is, the first groove 12a and the second groove 12b are formed concentrically.

Note that the first groove 12a and the second groove 12b are formed apart from each other, and a region (holding region 12c) in which no groove is formed is secured between the first groove 12a and the second groove 12b. ing. This holding area 12c constitutes a part of the holding surface 4a that holds the wafer 11.

FIG. 4(B) is an enlarged cross-sectional view showing the first groove 12a and the second groove 12b. For example, the first groove 12a and the second groove 12b are formed so that the width becomes narrower from the upper end to the lower end. In FIG. 4(B), the inner walls of the first groove 12a and the second groove 12b are inclined with respect to the depth direction of the first groove 12a and the second groove 12b (the height direction of the frame 6). An example is shown. That is, the first groove 12a and the second groove 12b are formed in a V-shape when viewed in cross section. However, there are no restrictions on the shapes of the first groove 12a and the second groove 12b.

The first groove 12a and the second groove 12b are each connected to the suction source 10 via a flow path 14. For example, the flow path 14 is configured by a through hole (space) formed inside the frame 6 and a tube or pipe connected to the through hole and the suction source 10. The through holes are formed to open at the bottoms of the first groove 12a and the second groove 12b.

The width and position of the first groove 12a and the second groove 12b are appropriately set according to the dimensions of the wafer 11, the dimensions of the holding surface 4a, and the like. For example, the width at the upper ends (holding surface 4a) of the first groove 12a and the second groove 12b is set to 0.1 mm or more and 1 mm or less (typically about 0.5 mm). Further, the width of the area between the outer peripheral edge of the holding surface 4a and the first groove 12a and the width of the area (holding area 12c) between the first groove 12a and the second groove 12b are, for example, 0.1 mm. It is set to 0.5 mm or less (typically about 0.2 mm).

Although FIG. 4A shows an example in which two grooves (first groove 12a and second groove 12b) are formed in the chuck table 4, the chuck table 4 has three or more grooves with different diameters. The annular grooves may be formed concentrically. Further, although FIG. 4A shows an example in which the first groove 12a and the second groove 12b are formed in a continuous linear shape, the shapes of the first groove 12a and the second groove 12b can be changed as appropriate. For example, the first groove 12a and the second groove 12b may each be formed in a discontinuous linear shape (broken line shape).

A ball screw type moving mechanism (not shown) and a rotation mechanism (not shown) such as a motor are connected to the chuck table 4. The moving mechanism moves the chuck table 4 along the processing feed direction (first horizontal direction). Further, the rotation mechanism rotates the chuck table 4 around a rotation axis that is generally parallel to the vertical direction (up and down direction).

As shown in FIG. 3, a cutting unit 16 is arranged above the chuck table 4. The cutting unit 16 includes a cylindrical housing 18, and a cylindrical spindle (rotating shaft) 20 is accommodated in the housing 18.

The spindle 20 is arranged along an indexing feed direction (second horizontal direction) that is generally parallel to the holding surface 4a of the chuck table 4 and generally perpendicular to the processing feed direction. The tip (one end side) of the spindle 20 protrudes from the housing 18, and an annular cutting blade 22 for cutting the wafer 11 is attached to this tip. Further, a rotational drive source (not shown) such as a motor for rotating the spindle 20 is connected to the base end (other end side) of the spindle 20.

For example, the cutting blade 22 is a hub-type cutting blade that is integrally configured with an annular base made of metal or the like and an annular cutting blade formed along the outer periphery of the base. The cutting edge of a hub-type cutting blade is composed of an electroformed grindstone in which abrasive grains made of diamond or the like are fixed by a binding material such as a nickel plating layer.

However, the materials of the abrasive grains and the binding material of the cutting blade 22 are not limited, and are appropriately selected depending on the material of the wafer 11 to be processed, processing conditions, and the like. Further, the cutting blade 22 may be a washer type cutting blade consisting of an annular cutting blade in which abrasive grains are fixed by a binding material made of metal, ceramics, resin, or the like.

A ball screw type moving mechanism (not shown) that moves the cutting unit 16 is connected to the cutting unit 16 . This moving mechanism moves the cutting unit 16 along the indexing and feeding direction and the vertical direction. As a result, the position and height (cutting depth into the wafer 11) of the cutting blade 22 attached to the cutting unit 16 in the indexing feed direction are adjusted.

When the wafer 11 is cut by the cutting device 2 described above and the wafer 11 is cut along the dividing line 13 (see FIG. 1(A)), the wafer 11 is divided into a plurality of device chips. Note that when dividing the wafer 11 into a plurality of device chips, the outer peripheral portion 21 (see FIG. 1B) of the wafer 11 that has not been subjected to the thinning process is first removed. This prevents the outer circumference 21 from interfering with dividing the wafer 11 or preventing the outer circumference 21 from interfering with picking up device chips after dividing the wafer 11 into a plurality of device chips.

FIG. 5 is a partially sectional front view showing the cutting device 2 that cuts the wafer 11. As shown in FIG. The outer circumference 21 is separated from the wafer 11 by cutting the wafer 11 in an annular shape along the outer circumference 21 with the cutting blade 22 .

When cutting the wafer 11 with the cutting device 2, the wafer 11 is first held by the chuck table 4. Specifically, the wafer 11 is placed on the chuck table 4 so that the front surface 11a side is exposed upward and the back surface 11b side (the recess 19 side, the tape 23 side) faces the holding surface 4a. At this time, the wafer 11 is placed so that the holding surface 4a side of the chuck table 4 is inserted into the recess 19. As a result, the bottom surface 19a of the recess 19 of the wafer 11 is supported by the holding surface 4a of the chuck table 4 via the tape 23.

Here, the suction path 8 of the chuck table 4 is provided at a position corresponding to the annular region (processed region 11d) of the wafer 11 that is cut by the cutting blade 22. Specifically, the first groove 12a and the second groove 12b are formed such that the area between the first groove 12a and the second groove 12b (holding area 12c) overlaps the processed area 11d of the wafer 11. . The wafer 11 is placed on the holding surface 4a with the processed area 11d and the suction path 8 (holding area 12c) aligned.

When the negative pressure of the suction source 10 is applied to the suction path 8 with the wafer 11 placed on the holding surface 4a, the bottom surface 19a of the recess 19 of the wafer 11 is inserted into the first groove 12a and the second groove through the tape 23. It is attracted to the groove 12b and held by the holding surface 4a. At this time, the wafer 11 has its processed region 11d supported by the holding region 12c, and both sides of the processed region 11d (radially inside and outside of the wafer 11) are connected to the first groove 12a and the second groove through the tape 23. It will be in a state where it is attracted by the groove 12b. Thereby, the processed region 11d of the wafer 11 is reliably fixed on the holding region 12c.

Note that the frame 25 is not fixed by a clamp or the like and is maintained in a floating state. Therefore, when the wafer 11 is held by the chuck table 4, the height position of the frame 25 is automatically adjusted so that the bottom surface 19a of the recess 19 is arranged along the holding surface 4a. This makes it possible to hold the wafer 11 horizontally along the holding surface 4a regardless of the depth of the recess 19.

In addition, an area (suction area) for sucking the wafer 11 may be provided on the holding surface 4a side of the chuck table 4 in addition to the first groove 12a and the second groove 12b. For example, a cylindrical recess (not shown) is formed in the center of the holding surface 4a side of the chuck table 4 (radially inner region of the second groove 12b), and a disc-shaped recess made of porous ceramics or the like is formed in this recess. A porous member may be fitted therein. In this case, a part (central part) of the holding surface 4a is constituted by the upper surface of the porous member.

The porous member described above is connected to the suction source 10 via a flow path 14, for example. Then, when the negative pressure of the suction source 10 acts on the porous member with the wafer 11 placed on the holding surface 4a, the central portion of the wafer 11 is attracted to the upper surface of the porous member. This improves the holding power of the wafer 11 by the chuck table 4.

Next, the processing region 11d of the wafer 11 is cut with the cutting blade 22, and the outer peripheral portion 21 of the wafer 11 is cut off. Note that the processed region 11d is an annular region of the wafer 11 that overlaps with the outer peripheral portion of the recess 19 (the region on the outer peripheral portion 21 side of the recess 19) and runs along the outer peripheral portion 21, that is, the outer peripheral portion of the recess 19. Corresponds to the bottom. The processed region 11d is preferably set so that the device region 17a (see FIG. 1(A)) is housed inside the processed region 11d in the radial direction.

First, the positions of the chuck table 4 and the cutting unit 16 are adjusted so that the cutting blade 22 is placed directly above a part of the processed region 11d. Then, the cutting unit 16 is lowered while rotating the cutting blade 22, and the cutting blade 22 is caused to cut into a part of the processed region 11d of the wafer 11. The amount of descent of the cutting unit 16 at this time is set so that the lower end of the cutting blade 22 reaches the tape 23.

Next, with the cutting blade 22 cutting into the wafer 11, the chuck table 4 is rotated while the rotation of the cutting blade 22 is maintained. As a result, the wafer 11 is cut and cut into an annular shape along the processed region 11d. As a result, the outer peripheral portion 21 of the wafer 11 is separated from the central portion of the wafer 11.

Here, as described above, the processed region 11d of the wafer 11 is reliably fixed on the holding region 12c by the negative pressure acting on the first groove 12a and the second groove 12b. Therefore, even if the rotating cutting blade 22 comes into contact with the processed area 11d, vibration (shaking) of the processed area 11d is unlikely to occur. This prevents damage to the wafer 11 (chipping, cracking, etc.).

Thereafter, the outer peripheral portion 21 separated from the wafer 11 is peeled off from the tape 23 and removed. Then, the wafer 11 is cut using the cutting blade 22 along the dividing line 13 (see FIG. 1(A)). Thereby, the wafer 11 is divided into a plurality of device chips each including a device 15 (see FIG. 1(A)). By dividing the thinned region of the wafer 11 in this manner, thinned device chips can be manufactured.

As described above, the cutting apparatus 2 according to the present embodiment includes the chuck table 4 in which the suction path 8 is provided in the area corresponding to the processed area 11d of the wafer 11. Thereby, the cutting device 2 can reliably fix the processed region 11d of the wafer 11 regardless of the depth of the recess 19 of the wafer 11, and the wafer 11 can be held appropriately and easily. Then, the vibration (shaking) of the wafer 11 when the cutting blade 22 contacts the processed region 11d is suppressed, and the occurrence of processing defects is prevented.

In the above embodiment, an example was described in which the wafer 11 is sucked by the first groove 12a and the second groove 12b provided on the holding surface 4a side of the chuck table 4, but the aspect of the suction path 8 is different from this. Not limited. FIG. 6(A) is a partially sectional front view showing the cutting device 2 in which the chuck table 4 is provided with the suction region 32 having unevenness.

The chuck table 4 shown in FIG. 6(A) is provided with a suction path 30 having a different configuration from the suction path 8 shown in FIG. 3 and the like. The suction path 30 includes an annular suction area 32 provided on the holding surface 4 a side of the chuck table 4 and a flow path 34 connecting the suction area 32 and the suction source 10 .

The suction area 32 corresponds to an area on the holding surface 4a side of the chuck table 4 in which fine irregularities are formed. This suction area 32 is provided at a position corresponding to the processed area 11d of the wafer 11. Specifically, the suction area 32 is provided in an annular shape so as to overlap the processed area 11d when the wafer 11 is held by the chuck table 4.

Note that the width and position of the suction area 32 are appropriately set according to the dimensions of the wafer 11, the dimensions of the holding surface 4a, and the like. For example, the width of the suction area 32 is set to 0.1 mm or more and 1 mm or less (typically about 0.5 mm). Further, the width of the area between the outer peripheral edge of the holding surface 4a and the suction area 32 is set to, for example, 0.05 mm or more and 0.2 mm or less (typically about 0.1 mm).

FIG. 6(B) is an enlarged cross-sectional view showing the suction region 32. As shown in FIG. The suction region 32 includes a plurality of convex portions (holding portions) 32a whose upper ends are arranged at approximately the same height position as the holding surface 4a, and concave portions (grooves) 32b provided between the plurality of convex portions 32a. That is, the suction area 32 is configured by a plurality of convex portions 32a and a concave portion 32b surrounding each convex portion 32a.

The upper ends of the plurality of convex portions 32a each constitute a part of the holding surface 4a, and hold the processed region 11d of the wafer 11. Further, the recess 32b is connected to the suction source 10 via the flow path 34. For example, the flow path 34 is configured by a through hole (space) formed inside the frame 6 and a tube or pipe connected to the through hole and the suction source 10. The through hole is formed to open at the bottom of the recess 32b of the suction area 32.

The suction area 32 can be formed by machining the outer peripheral portion of the chuck table 4 on the holding surface 4a side. For example, the suction area 32 is formed by forming unevenness on the holding surface 4a side of the chuck table 4 by sandblasting. Specifically, by spraying an abrasive onto the holding surface 4a side of the chuck table 4 using a sandblasting device, an annular region having irregularities is formed on the holding surface 4a side of the chuck table 4.

Note that the size and shape of the convex portion 32a and the concave portion 32b formed in the suction area 32 are appropriately set within a range where the negative pressure of the suction source 10 acts on the entire area of the suction area 32. For example, the suction region 32 is formed by sandblasting so that the surface roughness (maximum height Ry) of the holding surface 4a in the suction region 32 is 10 μm or more and 100 μm or less.

The wafer 11 is placed on the chuck table 4 so that the processed region 11d overlaps the suction region 32. When the negative pressure of the suction source 10 acts on the recess 32b of the suction region 32 in this state, the processed region 11d is supported by the convex portion 32a through the tape 23 and is sucked into the recess 32b through the tape 23. Ru. Thereby, the processed area 11d is reliably fixed on the suction area 32, and vibration (shaking) of the processed area 11d during cutting is suppressed.

Note that the suction area 32 is preferably formed so as not to reach the side surface of the frame 6. This prevents the negative pressure acting on the suction region 32 from leaking from the side surface of the frame 6 and weakening the holding force for the wafer 11.

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

11 Wafer 11a Front surface 11b Back surface 11c Side surface 11d Processing area 13 Planned dividing line (street)
15 Device 17a Device area 17b Surplus outer area 19 Recess 19a Bottom surface 19b Side surface (inner wall)
21 Outer periphery (convex part)
23 tape 25 frame 25a opening 2 cutting device 4 chuck table (holding table)
4a Holding surface 6 Frame body 8 Suction path 10 Suction source (suction unit)
12a First groove 12b Second groove 12c Holding area 14 Channel 16 Cutting unit 18 Housing 20 Spindle (rotating shaft)
22 cutting blade 30 suction path 32 suction area 32a convex part (holding part)
32b recess (groove)
34 Flow path

Claims (3)

A cutting device for cutting a wafer, comprising a recess formed in a central portion and an annular outer peripheral portion surrounding the recess,
a chuck table having a holding surface that holds the recess of the wafer;
a cutting unit that cuts the wafer held by the chuck table with a cutting blade;
A suction source;
The chuck table has an opening on the holding surface in a region of the wafer held by the chuck table that overlaps with the outer periphery of the concave portion and corresponds to a processed region to be cut by the cutting blade, and is connected to the suction source. It has a suction path where
The suction path includes a concentric first groove and a second groove provided on the holding surface side of the chuck table, and a flow path connecting the first groove and the second groove to the suction source; Equipped with
The chuck table supports the processed region of the wafer in a region between the first groove and the second groove, and also sucks the wafer between the first groove and the second groove. Characteristic cutting equipment. 2. The cutting device according to claim 1 , wherein the first groove and the second groove are formed so that the width becomes narrower from the upper end to the lower end. A cutting device for cutting a wafer, comprising a recess formed in a central portion and an annular outer peripheral portion surrounding the recess,
a chuck table having a holding surface that holds the recess of the wafer;
a cutting unit that cuts the wafer held by the chuck table with a cutting blade;
A suction source;
The chuck table has an opening on the holding surface in an area of the wafer held by the chuck table that overlaps with the outer periphery of the recess and corresponds to a processed area to be cut by the cutting blade, and is connected to the suction source. It has a suction path where
The suction path includes an annular suction area on the holding surface side of the chuck table with an uneven surface, and a flow path connecting the suction area and the suction source,
A cutting apparatus characterized in that the chuck table supports the processed area of the wafer with a convex portion of the suction area and suctions the wafer with a concave portion of the suction area.

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