JP2024041110A - Wafer processing method - Google Patents

Abstract

[Problem] To provide a wafer processing method capable of reducing the probability of device damage when a ring-shaped reinforcing part is separated from the wafer. [Solution] A processing method for a wafer in which a central region of a tape, with an outer periphery region attached to a ring frame, is attached to a back side of the wafer in which a recess is formed so as to thin a device region in which a plurality of devices are formed and an intermediate region surrounding the device region, and to leave an outer periphery excess region surrounding the intermediate region as a ring-shaped reinforcing part, the method comprising: a groove forming step of forming an annular inner groove and an annular outer groove, each of which penetrates the intermediate region and has its bottom surface located on the tape and is spaced apart from each other, by irradiating a laser beam of a wavelength absorbed by the wafer from the front side of the wafer; and a separation step of separating the ring-shaped reinforcing part from the tape after the groove forming step. [Selected Figure] Figure 2

Description

The present invention relates to a method for processing a wafer in which a central region of a tape, the peripheral region of which is attached to a ring frame, is attached to the back side of the wafer, on which a recess is formed so that a device region in which multiple devices are formed and an intermediate region surrounding the device region are thinned, and the peripheral excess region surrounding the intermediate region remains as a ring-shaped reinforcement portion.

2. Description of the Related Art Device chips such as ICs (Integrated Circuits) are essential components in various electronic devices such as mobile phones and personal computers. Such chips are manufactured, for example, by dividing a wafer, on which a plurality of devices are formed on the front side, along boundaries between the plurality of devices.

The wafer may be thinned prior to its division in order to reduce the size of manufactured chips. As a method for thinning a wafer, for example, a holding table that holds the wafer and a grinding wheel that is provided above the holding table and has a plurality of grinding wheels that are arranged discretely in an annular shape are used. Examples include grinding. This grinding is generally performed in the following order.

First, a wafer is held by a holding table so that the back surface is exposed. Next, the holding table is moved so that the center of the back surface of the wafer is positioned directly below the trajectory of the plurality of grinding wheels when the grinding wheel is rotated. Next, while rotating both the grinding wheel and the holding table, the grinding wheel is lowered so that the plurality of grinding wheels come into contact with the back surface of the wafer. As a result, the back side of the wafer is ground and the wafer is thinned.

However, as the wafer becomes thinner, its rigidity decreases and it becomes more susceptible to cracking. Therefore, a method has been proposed in which a recess is formed on the back surface of the wafer so that a region near the outer periphery of the wafer where no devices are formed (excess outer periphery region) remains as a ring-shaped reinforcing portion. In this method, a recess is formed on the back side of the wafer by grinding the back side of the wafer as described above using a grinding wheel having an outer diameter shorter than the radius of the wafer.

Furthermore, the ring-shaped reinforcement may become an obstacle when dividing the wafer along the boundaries of multiple devices. Therefore, the ring-shaped reinforcing portion may be separated from the wafer prior to this division (see, for example, Patent Document 1). For example, in this wafer, the wafer is divided in a region (intermediate region) located between a region where a plurality of devices are formed (device region) and a ring-shaped reinforcement section, and then the ring-shaped reinforcement section is separated. Ru.

Such division in the intermediate region of the wafer is sometimes performed using a laser beam with a wavelength that is absorbed by the wafer (see, for example, Patent Document 2). In this case, compared to the case where an annular cutting blade is used, the width of the region of the wafer to be removed can be narrowed, that is, the device region can be widened, and the processing time can be shortened.

Japanese Patent Application Publication No. 2011-61137 Japanese Patent Application Publication No. 2016-187004

When a wafer is divided in the middle region using a laser beam, the width of the region where the wafer is removed is approximately 25 μm, which is very narrow. Therefore, when separating the ring-shaped reinforcing part, the part including the ring-shaped reinforcing part may come into contact with the part including a plurality of devices. If the two come into contact, a crack will occur at the outer edge of the portion including a plurality of devices, and this crack may extend to the device, causing damage to the device.

In view of this, an object of the present invention is to provide a wafer processing method that can reduce the probability that a device will be damaged when separating a ring-shaped reinforcement from a wafer.

According to the present invention, a device region in which a plurality of devices are formed and an intermediate region surrounding the device region are thinned, and an outer peripheral surplus region surrounding the intermediate region remains as a ring-shaped reinforcement portion. A method for processing a wafer in which a central region of a tape whose outer peripheral region is stuck to a ring frame is attached to the back side where a recess is formed, and the tape is absorbed into the wafer from the front side of the wafer. forming an annular inner groove and an annular outer groove, each passing through the intermediate region and having a bottom surface located in the tape and spaced apart from each other by irradiating a laser beam with a wavelength; A method of processing a wafer is provided, comprising, after the groove forming step, a separating step of separating the ring-shaped reinforcement from the tape.

Preferably, the wafer processing method of the present invention further includes a dividing step of dividing the plurality of devices into individual devices after the separating step.

In the present invention, the ring reinforcement is separated after forming an inner groove and an outer groove, each of which penetrates the middle region of the wafer. That is, in the present invention, the ring-shaped reinforcing part is separated while the annular interference member is present between the part including the plurality of devices and the part including the ring-shaped reinforcing part (between the inner groove and the outer groove). be done.

In this case, even if a crack occurs at the outer edge of the interference member due to contact of the portion including the ring-shaped reinforcement with the interference member, this crack only extends to the inner edge of the interference member. That is, this crack will not extend to a portion that includes multiple devices.

In this case, the probability that the portion including the ring-shaped reinforcement portion comes into direct contact with the portion including multiple devices can be reduced. As a result, in the present invention, it is possible to reduce the probability that the device will be damaged when the ring-shaped reinforcement portion is separated from the wafer.

FIG. 1(A) is a perspective view schematically showing an example of a frame unit including a wafer, and FIG. 1(B) is a sectional view schematically showing the frame unit shown in FIG. 1(A). . FIG. 2 is a flowchart schematically showing an example of a wafer processing method for separating a ring-shaped reinforcing portion from a wafer included in a frame unit. 3(A), FIG. 3(B), and FIG. 3(C) are partially sectional side views schematically showing the groove forming step. 4(A), FIG. 4(B), and FIG. 4(C) are partially sectional side views schematically showing the state of the separation step. FIG. 5 is a partially sectional side view schematically showing the dividing step.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1(A) is a perspective view schematically showing an example of a frame unit including a wafer, and FIG. 1(B) is a sectional view schematically showing the frame unit shown in FIG. 1(A). . The frame unit 11 shown in FIGS. 1(A) and 1(B) includes a wafer 13 with a surface 13a exposed.

This wafer 13 is made of a single crystal semiconductor material such as silicon (Si), silicon carbide (SiC), or gallium nitride (GaN), for example. Furthermore, the wafer 13 has a device region 13b in which a plurality of devices 15 are formed, an intermediate region 13c surrounding the device region 13b, and an outer peripheral surplus region 13d surrounding the intermediate region 13c.

In this device region 13b, boundaries between the plurality of devices 15 are set in a grid pattern, and each of the plurality of linear portions included in this boundary is also referred to as a planned dividing line. Further, a recess 13f is formed on the back surface 13e of the wafer 13 so that the device region 13b and the intermediate region 13c are thinned, and the peripheral surplus region 13d remains as the ring-shaped reinforcing portion 17.

Further, a central region of a disk-shaped tape 19 having a diameter larger than that of the wafer 13 is attached to the back surface 13e of the wafer 13 so as to be in close contact with the wafer 13 in the recess 13f without any gaps. This tape 19 has, for example, a flexible film-like tape base material and an adhesive layer (glue layer) provided on the wafer 13 side of this tape base material.

The tape base material is made of polyolefin (PO), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS), or the like. Further, the adhesive layer is made of ultraviolet curable silicone rubber, acrylic material, epoxy material, or the like.

Furthermore, a ring frame 21 having an inner diameter larger than the diameter of the wafer 13 is attached to the outer peripheral area of the tape 19 . This ring frame 21 is made of a metal material such as aluminum or stainless steel.

FIG. 2 is a flowchart schematically showing an example of a wafer processing method for separating the ring-shaped reinforcing portion 17 from the wafer 13 included in the frame unit 11. In this method, first, an annular inner groove and an annular outer groove are formed, each of which penetrates the intermediate region 13c, has a bottom surface located on the tape 19, and is spaced apart from each other (groove formation step S1).

Each of FIGS. 3A, 3B, and 3C is a partially sectional side view schematically showing the groove forming step S1. Briefly, in FIG. 3(A), FIG. 3(B), and FIG. 3(C), the laser processing device 2 uses a laser beam LB having a wavelength that is absorbed by the wafer 13 to form an annular shape in the intermediate region 13c. The formation of two grooves 11a and 11b is shown.

The laser processing apparatus 2 includes a holding table 4 capable of holding a wafer 13 via a tape 19 on its upper surface. This holding table 4 has a disc-shaped frame 4a whose diameter is slightly shorter than the diameter of a recess 13f formed on the back surface 13e of the wafer 13.

This frame 4a is made of, for example, a metal material such as stainless steel or ceramics. Moreover, the frame 4a has a disc-shaped bottom wall and a cylindrical side wall that stands up from the outer peripheral area of the bottom wall. That is, a disc-shaped recess defined by a bottom wall and side walls is formed on the upper surface side of the frame 4a.

A disc-shaped porous plate (not shown) having a diameter approximately equal to the diameter of this recess is fixed to the recess formed on the upper surface side of the frame 4a. This porous plate is made of porous ceramics, for example.

Further, the holding table 4 is connected to a rotational drive source (not shown) such as a motor. When this rotation drive source is operated, the holding table 4 rotates about a straight line passing through the center of the upper surface of the holding table 4 and along the vertical direction as the rotation axis.

Further, the porous plate of the holding table 4 communicates with a suction source (not shown) such as an ejector through a through hole formed in the bottom wall of the frame 4a. When this suction source is operated, suction force is applied to the space near the top surface of the porous plate.

Furthermore, a plurality of clamps (not shown) are provided around the holding table 4 at approximately equal angular intervals along the circumferential direction of the holding table 4. Each of the plurality of clamps can grip the ring frame 21 included in the frame unit 11 and fix the ring frame 21 at a position lower than the upper surface of the holding table 4.

When the frame unit 11 is carried into the laser processing apparatus 2, the wafer 13 is placed on the holding table 10 via the tape 19 so that the recess 13f formed on the back surface 13e of the wafer 13 fits into the upper part of the holding table 10. It is placed at 4.

At this time, the ring frame 21 of the frame unit 11 is held at a position lower than the upper surface of the holding table 4 by being held by a plurality of clamps. Furthermore, when a suction source communicating with the porous plate of the holding table 4 is operated in this state, the wafer 13 is held on the holding table 4 via the tape 19.

A head 6 of a laser beam irradiation unit is provided above the holding table 4. This head 6 accommodates an optical system such as a condenser lens and a mirror. Further, the head 6 is connected to a ball screw type moving mechanism (not shown). When this moving mechanism is operated, the head 6 moves along the horizontal and/or vertical direction.

Further, the laser beam irradiation unit includes a laser oscillator (not shown) that generates a laser beam LB having a wavelength (for example, 355 nm) that is absorbed by the wafer 13. This laser oscillator has, for example, Nd:YAG as a laser medium. When the laser beam LB is generated by the laser oscillator, the laser beam LB is irradiated directly below from the head 6 via an optical system housed in the head 6.

When forming the grooves 11a and 11b in the frame unit 11 held by the holding table 4 and a plurality of clamps, first, the focusing point of the laser beam LB irradiated from the head 6 is located in the intermediate region 13c. Move the head 6 so that it is positioned. For example, the head 6 is moved so that this focal point is positioned slightly outside the inner peripheral edge of the intermediate region 13c.

Next, the holding table 4 is rotated at least once while irradiating the laser beam LB from the head 6 toward the wafer 13 (see FIG. 3(A)). Note that the rotational speed of the holding table 4 at this time is, for example, about 0.1 r/s. That is, this holding table 4 rotates once in about 10 seconds, for example.

As a result, laser ablation occurs in the intermediate region 13c, and the wafer 13 is divided. In other words, a groove (inner groove) 11a is formed that penetrates the intermediate region 13c of the wafer 13 and whose bottom surface is located on the tape 19. Note that the width of the groove 11a along the radial direction of the wafer 13 is, for example, about 25 μm.

Next, the head 6 is moved along the radial direction of the wafer 13 (see FIG. 3(B)). For example, the head 6 is moved so that the focal point on which the laser beam LB emitted from the head 6 is focused is positioned slightly inside the outer periphery of the intermediate region 13c.

Next, as described above, the holding table 4 is rotated at least once while the laser beam LB is irradiated from the head 6 toward the wafer 13 (see FIG. 3(C)). As a result, a groove (outside groove) 11b is formed that penetrates the intermediate region 13c of the wafer 13, has a bottom surface located on the tape 19, and is spaced apart from the groove 11a. Note that the width of the groove 11b along the radial direction of the wafer 13 is, for example, about 25 μm.

Furthermore, along with the formation of the pair of grooves 11a and 11b, an annular interference member 23 is formed between the portion including the plurality of devices 15 and the portion including the ring-shaped reinforcing portion 17. Note that the width of the interference member 23 along the radial direction of the wafer 13 is, for example, about 100 μm.

After the groove forming step S1, the ring-shaped reinforcing portion 17 is separated from the tape 19 (separation step S2). 4(A), FIG. 4(B), and FIG. 4(C) are partially sectional side views schematically showing the state of the separation step S2. Briefly, in FIGS. 4(A), 4(B), and 4(C), in the separating device 8, an upward external force is applied to the ring-shaped reinforcing portion 17 to remove the ring-shaped reinforcing portion 17 from the tape 19. The separation of the two is shown.

Separation device 8 includes a holding table 10 . This holding table 10 has the same structure as the holding table 4 shown in FIGS. 3(A), 3(B), and 3(C). That is, the holding table 10 includes a disc-shaped frame 10a and a disc-shaped porous plate fixed in a recess formed on the upper surface of the frame 10a.

Further, the porous plate of the holding table 10 communicates with a suction source (not shown) such as an ejector through a through hole formed in the bottom wall of the frame 10a. When this suction source is operated, suction force is applied to the space near the top surface of the porous plate.

Furthermore, a plurality of clamps (not shown) are provided around the holding table 10 at approximately equal angular intervals along the circumferential direction of the holding table 10. Each of the plurality of clamps can grip the ring frame 21 included in the frame unit 11 and fix the ring frame 21 at a position lower than the upper surface of the holding table 10.

Then, when the frame unit 11 in which the grooves 11a and 11b are formed is carried into the separation device 8, the interference member 23 and the plurality of devices 15 are attached to each other via the tape 19 so that the holding table 10 is surrounded by the ring-shaped reinforcing part 17. and placed on the holding table 10.

At this time, the ring frame 21 of the frame unit 11 is held by a plurality of clamps and held at a position lower than the upper surface of the holding table 10. Furthermore, when the suction source communicating with the porous plate of the holding table 10 is operated in this state, the plurality of devices 15 and the interference member 23 are held on the holding table 10 via the tape 19.

A separation unit 12 is provided above the holding table 10. This separation unit 12 has a cylindrical support member 14 . A ball screw type lifting mechanism (not shown) and a rotational drive source such as a motor are connected to the upper part of the support member 14.

Then, by operating this elevating mechanism, the support member 14 is moved up and down. Further, by operating this rotational drive source, the support member 14 rotates about a straight line passing through the center of the support member 14 and along a direction perpendicular to the upper surface of the holding table 10 as the rotation axis.

Further, the lower end portion of the support member 14 is fixed to the center of the upper part of a disc-shaped base 16. A plurality of movable members 18 are provided below the outer peripheral portion of the base 16 along the circumferential direction of the base 16 at approximately equal angular intervals. The movable member 18 has a plate-shaped hanging portion 18a extending downward from the lower surface of the base 16.

The upper end of this hanging portion 18a is connected to an actuator such as an air cylinder built into the base 16, and by operating this actuator, the movable member 18 moves along the radial direction of the base 16. Further, a plate-shaped wedge portion 18b that extends toward the center of the base 16 and becomes thinner toward the tip is provided on the inner surface of the lower end portion of the hanging portion 18a.

When separating the ring-shaped reinforcing portion 17 included in the frame unit 11 held by the holding table 10 and the plurality of clamps from the tape 19, first, a plurality of The movable member 18 is moved.

Next, the support member 14, the base 16, and the plurality of movable members 18 are moved so that the tips of the wedge portions 18b of the plurality of movable members 18 are positioned at a height corresponding to the interface between the tape 19 and the ring-shaped reinforcing portion 17. to raise and lower.

Next, the plurality of movable members 18 are moved so that the wedge portions 18b enter this interface (see FIG. 4(A)). As a result, the ring-shaped reinforcing portion 17 is peeled off from the tape 19 at the location where the wedge portion 18b has entered.

Next, the support member 14, the base 16, and the plurality of movable members 18 are rotated so that the wedge portion 18b that has entered this interface rotates around the holding table 10 (see FIG. 4(B)). As a result, the entire ring-shaped reinforcing portion 17 is peeled off from the tape 19.

Next, the support member 14, the base 16, and the plurality of movable members 18 are raised so that the ring-shaped reinforcing portion 17 is separated from the tape 19 (see FIG. 4(C)). With the above steps, the wafer processing method shown in FIG. 2 is completed.

In this method, the ring-shaped reinforcing portion 17 is separated after forming grooves 11a and 11b, each of which penetrates the intermediate region 13c of the wafer 13. That is, in this method, the ring-shaped reinforcing part 17 is separated with the annular interference member 23 existing between the part including the plurality of devices 15 and the part including the ring-shaped reinforcing part 17.

In this case, even if a crack occurs at the outer edge of the interference member 23 due to contact of the portion including the ring-shaped reinforcing portion 17 with the interference member 23, this crack only extends to the inner edge of the interference member 23. That is, this crack does not extend to a portion including a plurality of devices 15.

Further, in this case, the probability that the portion including the ring-shaped reinforcing portion 17 comes into direct contact with the portion including the plurality of devices 15 can be reduced. As a result, in this method, it is possible to reduce the probability that the device 15 will be damaged when separating the ring-shaped reinforcing portion 17 from the wafer 13.

Note that the content described above is one aspect of the present invention, and the content of the present invention is not limited to the content described above. For example, in the groove forming step S1 of the present invention, the groove (inner groove) 11a may be formed after the groove (outer groove) 11b is formed.

Alternatively, in the groove forming step S1 of the present invention, the two grooves 11a and 11b may be formed simultaneously by branching the laser beam LB into two and irradiating the intermediate region 13c of the wafer 13. In order to branch the laser beam LB in this way, the laser beam irradiation unit of the laser processing device 2 uses a spatial light modulator including a liquid crystal phase control element called LCoS (Liquid Crystal on Silicon) and/or a diffractive optical element. (DOE) etc. may also be included.

Further, the laser processing apparatus used in the groove forming step S1 of the present invention is not limited to the laser processing apparatus 2 shown in FIGS. 3(A), 3(B), and 3(C). For example, in the groove forming step S1 of the present invention, a moving mechanism that moves the holding table 4 is provided in place of or in addition to the rotational drive source that rotates the holding table 4 and/or the moving mechanism that moves the head 6. A laser processing device may also be used.

In addition, in the groove forming step S1 of the present invention, instead of or in addition to the rotational drive source that rotates the holding table 4 and/or the moving mechanism that moves the head 6, the direction of the laser beam LB irradiated from the head 6 is controlled. A laser processing device may be used in which a changeable scanning optical system is provided in the laser beam irradiation unit. Note that this scanning optical system includes, for example, a galvano scanner, an acousto-optic device (AOD), and/or a polygon mirror.

That is, in the groove forming step S1 of the present invention, it is only necessary that the wafer 13 held by the holding table 4 and the focal point on which the laser beam LB irradiated from the head 6 is focused can be moved relative to each other. There is no limit to the structure.

In addition, in the groove forming step S1 of the present invention, a laser beam is provided which includes a holding table capable of holding the wafer 13 via the tape 19 on the lower surface and a laser beam irradiation unit capable of irradiating the laser beam LB directly upward from the head. Processing equipment may also be used. That is, in the groove forming step S1 of the present invention, the grooves 11a and 11b may be formed using the laser beam LB irradiated from directly below the wafer 13.

Furthermore, the separation device used in the separation step S2 of the present invention is not limited to the separation device 8 shown in FIGS. 4(A), 4(B), and 4(C). For example, in the separation step S2 of the present invention, the separation includes a holding table capable of holding the wafer 13 via the tape 19 on the lower surface and a separation unit capable of applying a downward external force to the ring-shaped reinforcing part 17. A device may be used.

Further, the groove forming step S1 and the separating step S2 of the present invention are performed in a single processing device capable of performing both the irradiation of the wafer 13 with the laser beam LB and the separation of the ring-shaped reinforcing portion 17 from the tape 19. may be implemented. In this case, the groove forming step S1 and the separating step S2 of the present invention may be performed while the frame unit 11 is held on a single holding table.

Note that when applying a downward external force to the ring-shaped reinforcing part 17 to separate the ring-shaped reinforcing part 17 from the tape 19, the part of the ring-shaped reinforcing part 17 separated from the tape 19 is pulled downward by gravity. The ring-shaped reinforcing portion 17 tends to tilt. When the ring-shaped reinforcing part 17 is tilted in this way, the part including the plurality of devices 15 and the part including the ring-shaped reinforcing part 17 are likely to come into contact with each other. Therefore, the wafer processing method of the present invention is suitable for applying a downward external force to the ring-shaped reinforcing part 17 to separate the ring-shaped reinforcing part 17 from the tape 19.

Further, the wafer processing method of the present invention may further include a dividing step of dividing the plurality of devices 15 into individual devices after the separating step S2. FIG. 5 is a partially sectional side view schematically showing this dividing step.

Briefly, FIG. 5 shows how a plurality of devices 15 are individually divided by cutting a portion including a plurality of devices 15 together with an interference member 23 in the cutting device 20. Note that the X-axis direction (processing feed direction) and Y-axis direction (indexing feed direction) shown in FIG. 2 are directions perpendicular to each other on the horizontal plane, and the Z-axis direction (cutting feed direction) is This is a direction (vertical direction) perpendicular to each of the Y-axis directions.

The cutting device 20 includes a holding table 22. This holding table 22 has the same structure as the holding table 4 shown in FIGS. 3(A), 3(B), and 3(C). That is, the holding table 22 includes a disc-shaped frame 22a and a disc-shaped porous plate fixed to a recess formed on the upper surface side of the frame 22a.

Further, the porous plate of the holding table 22 communicates with a suction source (not shown) such as an ejector through a through hole formed in the bottom wall of the frame 22a. When this suction source is operated, suction force is applied to the space near the top surface of the porous plate.

Furthermore, a plurality of clamps (not shown) are provided around the holding table 22 at approximately equal angular intervals along the circumferential direction of the holding table 22. Each of the plurality of clamps can grip the ring frame 21 included in the frame unit 11 and fix the ring frame 21 at a position lower than the upper surface of the holding table 22.

Further, the holding table 22 is connected to a ball screw type X-axis movement mechanism (not shown) and a rotational drive source such as a motor. Then, when the X-axis direction movement mechanism is operated, the holding table 22 moves along the X-axis direction. Further, when this rotation drive source is operated, the holding table 22 rotates about a straight line passing through the center of the upper surface of the holding table 22 and along the vertical direction as the rotation axis.

Then, when the frame unit 11 from which the ring-shaped reinforcing portion 17 has been separated from the tape 19 is carried into the cutting device 20, the plurality of devices 15 and interference members 23 are placed on the holding table 22 via the tape 19.

At this time, the ring frame 21 of the frame unit 11 is held by a plurality of clamps and held at a position lower than the upper surface of the holding table 22. Furthermore, when the suction source communicating with the porous plate of the holding table 22 is operated in this state, the plurality of devices 15 and the interference member 23 are held on the holding table 22 via the tape 19.

A cutting unit 24 is provided above the holding table 22. This cutting unit 24 has a spindle (not shown) extending along the Y-axis direction, and a cutting blade 26 attached to the tip of the spindle.

Further, the base end of the spindle is connected to a rotational drive source (not shown) such as a motor. When this rotational drive source is operated, the cutting blade 26 rotates together with the spindle with a straight line along the Y-axis direction as the rotation axis.

Furthermore, the cutting unit 24 is connected to a Y-axis moving mechanism (not shown) and a Z-axis moving mechanism (not shown), each of which is a ball screw type. When the Y-axis moving mechanism is operated, the cutting unit 24 moves along the Y-axis direction, and when the Z-axis moving mechanism is operated, the cutting unit 24 moves along the Z-axis direction.

When individually dividing the plurality of devices 15 included in the frame unit 11 held by the holding table 22 and the plurality of clamps, first, a linearly extending portion of the boundary of the plurality of devices 15 (to be divided The holding table 22 is rotated so that one of the lines) is parallel to the X-axis direction.

Next, the holding table 22 and the cutting blade are positioned so that the cutting blade 26 is positioned in the X-axis direction when viewed from this planned dividing line, and the lower end of the cutting blade 26 is positioned at a height corresponding to the tape 19 placed on the holding table 22. Move unit 24.

Next, while rotating the cutting blade 26 together with the spindle, the holding table 22 is moved along the X-axis direction so that the lower end of the cutting blade 26 passes from one end to the other end of the interference member 23 in the X-axis direction (Fig. 5). As a result, the portion including the plural devices 15 together with the interference member 23 is divided along the planned dividing line.

Furthermore, the above-described operation is repeated so that the plurality of devices 15 are divided together with the interference member 23 at all the boundaries of the plurality of devices 15. As a result, the plurality of devices 15 are individually divided.

Note that, prior to the above-mentioned dividing step, a shrinking step is performed to shrink the portion of the tape 19 that is bent due to the separation of the ring-shaped reinforcing portion 17, typically, the portion to which the ring-shaped reinforcing portion 17 was stuck. may be implemented. This shrinking step is carried out, for example, by blowing hot air onto the part.

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

2: Laser processing device 4: Holding table (4a: frame)
6: Laser beam irradiation unit 8: Separation device 10: Holding table 11: Frame unit (11a: groove (inner groove), 11b: groove (outer groove))
12: Separation unit 13: Wafer (13a: surface, 13b: device region, 13c: intermediate region)
(13d: Surplus outer area, 13e: Back surface, 13f: Concave part)
14: Support member 15: Device 16: Base 17: Ring-shaped reinforcement part 18: Movable member (18a: hanging part, 18b: wedge part)
19: Tape 20: Cutting device 21: Ring frame 22: Holding table 23: Interference member 24: Cutting unit 26: Cutting blade

Claims (2)

A recess is formed so as to thin a device region in which a plurality of devices are formed and an intermediate region surrounding the device region, and to leave an outer periphery surplus region surrounding the intermediate region as a ring-shaped reinforcing portion. A method for processing a wafer in which a central region of a tape whose outer peripheral region is stuck to a ring frame is attached to the back side,
By irradiating a laser beam with a wavelength absorbed by the wafer from the front side of the wafer, annular inner grooves and annular grooves are formed, each passing through the intermediate region and having a bottom surface located on the tape and spaced apart from each other. a groove forming step forming an outer groove of the
a separating step of separating the ring-shaped reinforcement from the tape after the groove forming step;
A wafer processing method comprising: The wafer processing method according to claim 1, further comprising a dividing step of dividing the plurality of devices into individual devices after the separating step.

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