JP2021118260A - Division method of workpiece - Google Patents

Abstract

To provide a new division method of a workpiece that reduces the possibility of device contamination when the workpiece is divided.SOLUTION: A division method of a workpiece used to divide a workpiece including a recess in which a device is formed on the bottom surface partitioned by a planned division line and a ring-shaped reinforcing portion surrounding the recess includes a tape application step of attaching a first tape to a reinforcing portion without contacting the bottom surface of the recess and sealing a space inside the recess with the first tape, a starting point region forming step of forming a starting point region which is a starting point of division from the surface side opposite to the first tape of the workpiece to which the first tape is attached to the reinforcing portion on the planned division line, a tape reattachment step of attaching a second tape to the surface side of the workpiece and peeling off the first tape from the reinforcing portion, and a division step of expanding the second tape and dividing the workpiece starting from the starting point region.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for dividing a work piece used when dividing a plate-shaped work piece.

In electronic devices such as mobile phones and personal computers, a device chip including a device such as an electronic circuit is an indispensable component. In the device chip, for example, the surface of a wafer made of a semiconductor material such as silicon is divided into a plurality of regions by a planned division line (street), a device is formed in each region, and then the wafer is placed along the planned division line. Obtained by dividing.

When dividing a wafer into a plurality of device chips, for example, a cutting device equipped with an annular cutting blade in which abrasive grains such as diamond are hardened with a binder such as metal or resin is used. By rotating the cutting blade at high speed and cutting into the wafer along the planned division line, the wafer can be divided into a plurality of device chips. The wafer after being divided is cleaned by a cleaning unit included in the cutting apparatus (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2006-339435

By the way, when a plate-shaped workpiece such as a wafer is divided by using the above-mentioned cutting device, a protective tape is attached to the back surface side of the workpiece, and the workpiece is passed through this tape. By holding the device, the workpiece is often cut with the device exposed. However, in this method, dust and dirt generated by cutting tend to adhere to the device and the like.

Dust and dust adhering to the device are not completely removed even if the work piece is washed later, which causes defects. On the other hand, it is also conceivable to attach a tape to the front surface side of the workpiece and cut the workpiece with the back surface exposed. However, in this case, the adhesive of the tape may remain on the device on the front surface side, which may cause a defect.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a new method for dividing a work piece, which can reduce the possibility of contaminating the device when the work piece is divided. To provide.

According to one aspect of the present invention, a work piece used for dividing a workpiece having a recess in which a device is formed on a bottom surface partitioned by a planned division line and a ring-shaped reinforcing portion surrounding the recess. A method of dividing a work piece, the tape sticking step of sticking the first tape to the reinforcing portion without contacting the bottom surface of the recess and sealing the space inside the recess with the first tape, and the reinforcing. A starting point region forming step of forming a starting point region to be a starting point of division on the planned division line from the surface side opposite to the first tape of the work piece to which the first tape is attached to the portion, and a second tape. Is attached to the surface side of the work piece, and the tape reattachment step of peeling the first tape from the reinforcing portion, and expanding the second tape to start the work piece from the starting point region. A method for dividing a workpiece is provided with a division step for dividing.

In one aspect of the present invention, in the starting point region forming step, a cutting blade provided with a cutting blade containing abrasive grains is rotated to cut into the surface side of the work piece, and a groove serving as a starting point of division is formed. It may be formed on the planned division line.

Further, in one aspect of the present invention, in the starting point region forming step, a laser beam having a wavelength absorbed by the workpiece is irradiated on the surface side of the workpiece, and a groove serving as a starting point of division is divided. May form on the scheduled line.

In the method of dividing the workpiece according to one aspect of the present invention, the first tape is attached to the reinforcing portion without contacting the bottom surface where the device of the recess is formed, and the space inside the recess is sealed with the first tape. Later, since the starting point region that becomes the starting point of the division is formed from the surface opposite to the first tape, the starting point region is formed on the workpiece while keeping the space inside the recess in which the device is placed clean. can.

That is, it is possible to prevent dust and dirt generated when forming the starting point region from adhering to the device. In addition, the adhesive of the tape does not remain on the device as in the case where the tape is applied to the area where the device of the workpiece is formed. Therefore, according to the method for dividing a work piece according to one aspect of the present invention, the possibility that the device is contaminated when the work piece is divided can be suppressed to a low level.

FIG. 1 is a perspective view schematically showing a work piece. FIG. 2 is a cross-sectional view schematically showing a work piece to which the first tape is attached. FIG. 3 is a cross-sectional view schematically showing how a groove serving as a starting point of division is formed in a work piece. FIG. 4 is a cross-sectional view schematically showing a work piece in which a groove is formed. FIG. 5 is a cross-sectional view schematically showing a work piece to which the second tape is attached. FIG. 6 is a cross-sectional view schematically showing a work piece from which the first tape has been peeled off. FIG. 7 is a cross-sectional view schematically showing how the workpiece is divided.

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a work piece 11 to be divided by the work piece division method according to the present embodiment. The workpiece 11 is, for example, a disk-shaped wafer formed by using a semiconductor such as silicon, and has a first surface (front surface) 11a and a second surface (back surface) located on the opposite side of the first surface 11a. ) 11b and.

The first surface 11a and the second surface 11b are both substantially flat and substantially parallel to each other. A concave portion 13 having a circular shape when viewed from the first surface 11a side is provided in the central region of the workpiece 11 on the first surface 11a side. That is, the recess 13 opens to the first surface 11a, and the space inside the recess 13 is connected to the space outside the workpiece 11 on the first surface 11a side.

The ring-shaped region surrounding the recess 13 of the workpiece 11 is a reinforcing portion 15 that supplements the strength of the workpiece 11 that is insufficient due to the recess 13. The thickness of the ring-shaped reinforcing portion 15 (distance between the first surface 11a and the second surface 11b) is larger than the distance between the bottom surface 13a of the recess 13 and the second surface 11b.

The bottom surface 13a of the recess 13 is divided into a plurality of regions by a plurality of scheduled division lines 17 intersecting with each other, and a device 19 such as an IC (Integrated Circuit) is formed in each region. There are no restrictions on the material, shape, structure, size, etc. of the workpiece 11. For example, a substrate formed of other semiconductors, ceramics, resins, metals, etc. can be used as the workpiece 11. Similarly, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the device 19.

In such a workpiece 11, for example, a central region of a wafer or the like having two planes substantially parallel to each other is thinned by a method such as etching or grinding to form a recess 13, and the bottom surface 13a of the recess 13 is formed. It is obtained by forming the device 19 in the device 19. By using the workpiece 11 having the recess 13 and the reinforcing portion 15, it is possible to realize a method of dividing the workpiece with a low possibility that the device 19 is contaminated. However, there are no particular restrictions on the method of obtaining the workpiece 11.

In the method of dividing the workpiece according to the present embodiment, first, the space inside the recess 13 is sealed so that the dust and dirt generated when the workpiece 11 is processed does not adhere to the device 19. Specifically, a tape (first tape) having a size capable of covering the recess 13 is attached to the first surface 11a side of the reinforcing portion 15, and the space inside the recess 13 and the outside of the workpiece 11 are attached. Separate the space (tape application step).

FIG. 2 is a cross-sectional view schematically showing a work piece 11 to which the first tape 21 is attached. The first tape 21 includes a film-like base material layer and an adhesive layer provided on substantially the entire surface of one surface of the base material layer and exhibiting adhesive strength to the workpiece 11. The base material layer of the first tape 21 is formed of, for example, a material such as polyolefin, polyvinyl chloride, or polyethylene terephthalate, and the adhesive layer of the first tape 21 is formed of, for example, an acrylic or rubber-based material. ..

The first tape 21 is formed, for example, in a circular shape having a diameter similar to the outer diameter of the first surface 11a (or the second surface 11b) of the workpiece 11. When the first tape 21 is attached to the workpiece 11, the adhesive layer located on the outer peripheral portion of the first tape 21 is brought into close contact with the first surface 11a of the reinforcing portion 15 of the workpiece 11.

More specifically, the first tape 21 is used as a work piece so that there is no gap between the first surface 11a of the reinforcing portion 15 and the adhesive layer of the first tape 21 in the entire circumferential direction of the work piece 11. Adhere to 11. As a result, the space inside the recess 13 is sealed with the first tape 21. However, the first tape 21 is prevented from coming into contact with the bottom surface 13a of the recess 13. This is because when the first tape 21 is brought into contact with the bottom surface 13a, there is a high possibility that the material (adhesive) constituting the adhesive layer of the first tape 21 adheres to the device 19 and remains.

After the first tape 21 is attached to the reinforcing portion 15, the groove (starting point region) that becomes the starting point of division from the second surface 11b side of the workpiece 11 (that is, the surface side opposite to the first tape 21). Is formed on the scheduled division line 17 (starting point region forming step). FIG. 3 is a cross-sectional view schematically showing how a groove 17a, which is a starting point of division, is formed in the workpiece 11.

When forming the groove 17a in the workpiece 11, for example, the cutting device 2 shown in FIG. 3 is used. The cutting device 2 includes, for example, a chuck table (vacuum chuck) (not shown) having a substantially flat holding surface suitable for holding the workpiece 11. This chuck table is connected to a rotation drive source such as a motor, and rotates around a rotation axis substantially perpendicular to the holding surface described above. Further, the chuck table is supported by a ball screw type moving mechanism, and moves in the machining feed direction substantially parallel to the holding surface described above.

A cutting unit 4 is arranged above the chuck table. The cutting unit 4 includes, for example, a spindle 6 having an axis substantially parallel to the holding surface of the chuck table and substantially perpendicular to the machining feed direction. A cutting blade 8 provided with a cutting blade containing abrasive grains is mounted on one end side of the spindle 6. A rotary drive source (not shown) such as a motor is connected to the other end side of the spindle 6, and the cutting blade 8 mounted on one end side of the spindle 6 is rotated by the power of the rotary drive source.

The cutting unit 4 is supported by a ball screw type moving mechanism (not shown). By this moving mechanism, the cutting blade 8 moves in the indexing feed direction, which is substantially parallel to the holding surface of the chuck table and substantially perpendicular to the machining feed direction, and the vertical direction, which is substantially perpendicular to the holding surface. On the side of the cutting blade 8, a nozzle (not shown) for supplying a liquid (cutting fluid) such as water to the cutting blade 8 and the workpiece 11 is arranged.

When the groove 17a serving as the starting point of division is formed on the scheduled division line 17, the base material layer side of the first tape 21 attached to the workpiece 11 is brought into contact with the holding surface of the chuck table, and the chuck is formed. Hold the workpiece 11 on the table. That is, the workpiece 11 is held by the chuck table so that the second surface 11b side is exposed upward.

After holding the workpiece 11 on the chuck table, for example, the chuck table is rotated to make an arbitrary scheduled division line 17 substantially parallel to the machining feed direction. Next, the chuck table and the cutting unit 4 are relatively moved to align the cutting blade 8 above the extension line of the planned division line 17. When confirming the position of the planned division line 17, it is preferable to take an image of the device 19 from the second surface 11b side with an infrared camera or the like. A mark indicating the planned division line 17 may be attached to the second surface 11b or the like of the workpiece 11.

Further, the height of the cutting unit 4 with respect to the chuck table is adjusted so that the height of the lower end of the cutting blade 8 is lower than the height of the second surface 11b of the workpiece 11 and higher than the height of the bottom surface 13a. Then, while rotating the cutting blade 8, the chuck table is moved in the machining feed direction to cut the cutting blade 8 into the workpiece 11. When the cutting blade 8 is cut into the workpiece 11, the liquid is supplied from the nozzle to the cutting blade 8 and the workpiece 11.

As a result, the rotated cutting blade 8 can be cut into the second surface 11b side of the workpiece 11, and the groove 17a can be formed in the target division scheduled line 17. In the present embodiment, since the height of the lower end of the cutting blade 8 is higher than the height of the bottom surface 13a, the groove 17a formed does not penetrate the workpiece 11. In other words, the formed groove 17a does not open to the bottom surface 13a.

Therefore, dust and dirt generated when the groove 17a is formed does not enter the space inside the recess 13 and adhere to the device 19. The same procedure is repeated until the grooves 17a are formed in all the scheduled division lines 17. FIG. 4 is a cross-sectional view schematically showing the workpiece 11 in which the groove 17a is formed.

When forming the groove 17a in the workpiece 11, not only the region overlapping the bottom surface 13a when viewed from the second surface 11b side (the region inside the reinforcing portion 15), but also when viewed from the second surface 11b side. It is desirable to form a groove 17a in a region (reinforcing portion 15) outside the bottom surface 13a. As a result, the entire workpiece 11 including the reinforcing portion 15 can be appropriately divided.

In this case, the groove 17a of the reinforcing portion 15 may be formed deeper than the groove 17a in the region inside the reinforcing portion 15. The deep groove 17a of the reinforcing portion 15 can be formed, for example, by a method called a chopper cut in which the rotated cutting blade 8 is cut from directly above. If the reinforcing portion 15 is removed before the workpiece 11 is divided, it is not necessary to form the groove 17a in the region outside the bottom surface 13a.

After the groove 17a serving as the starting point of the division is formed on the workpiece 11, another tape (second tape) is attached to the second surface 11b side of the workpiece 11, and the first tape 21 is attached to the reinforcing portion 15 (reinforcing portion 15 (2nd tape). It is peeled off from the first surface 11a) of the workpiece 11 (tape replacement step). FIG. 5 is a cross-sectional view schematically showing a work piece 11 to which the second tape 23 is attached, and FIG. 6 is a cross-sectional view schematically showing a work piece 11 to which the first tape 21 is peeled off. be.

The structure and material of the second tape 23 are the same as those of the first tape 21, for example. That is, the second tape 23 includes a film-like base material layer and an adhesive layer provided on substantially the entire surface of one surface of the base material layer and exhibiting adhesive strength to the workpiece 11. However, the second tape 23 is formed so as to be larger than the outer edge of the first surface 11a (or the second surface 11b) of the workpiece 11.

When the second tape 23 is attached to the workpiece 11, as shown in FIG. 5, the adhesive layer of the second tape 23 is brought into close contact with the entire second surface 11b of the workpiece 11. By attaching the second tape 23 to the entire second surface 11b in this way, when the second tape 23 is expanded, a force is applied to the entire second surface 11b to appropriately apply the workpiece 11. You will be able to divide it. After the second tape 23 is attached to the workpiece 11, the first tape 21 is peeled off from the reinforcing portion 15 as shown in FIG.

In the present embodiment, the first tape 21 is peeled off from the reinforcing portion 15 after the second tape 23 is attached to the workpiece 11, but the first tape 21 is peeled off from the reinforcing portion 15 and then covered. The second tape 23 may be attached to the work piece 11. Further, the ring-shaped frame may be fixed to the second tape 23 so that the workpiece 11 is accommodated in the opening of the ring-shaped frame having an opening larger than that of the workpiece 11.

After the second tape 23 is attached to the workpiece 11 and the first tape 21 is peeled off from the reinforcing portion 15, the second tape 23 is expanded to divide the workpiece 11 starting from the groove 17a (division step). ). FIG. 7 is a cross-sectional view schematically showing how the workpiece 11 is divided. When dividing the workpiece 11, for example, an expansion device including a cylindrical expansion drum having a diameter larger than that of the workpiece 11 is used.

Specifically, the expansion drum of the expansion device and the second tape 23 are relatively moved, and the end surface of the expansion drum corresponding to the bottom surface of the cylinder is abutted against the base material layer of the second tape 23. As a result, the second tape 23 is expanded in the radial direction (that is, isotropically) of the expansion drum, and the force applied to the workpiece 11 due to the expansion of the second tape 23 causes the workpiece 11 to expand. It is divided into a plurality of chips 31.

There is no limitation on the specific method for dividing the workpiece 11. In the present embodiment, an expansion device provided with a cylindrical expansion drum is used to divide the workpiece 11 by isotropically expanding the second tape 23. For example, with respect to the planned division line 17. The second tape 23 can be extended in the vertical direction to divide the workpiece 11.

As described above, in the method of dividing the workpiece according to the present embodiment, the first tape 21 is attached to the reinforcing portion 15 without contacting the bottom surface 13a on which the device 19 of the recess 13 is formed, and the inside of the recess 13 is formed. After sealing the space with the first tape 21, a groove (starting point region) 17a serving as a starting point of division is formed from the side of the second surface 11b opposite to the first tape 21, so that the recess 13 in which the device 19 is arranged is arranged. A groove 17a can be formed in the workpiece 11 while keeping the space inside the work piece 11 in a clean state.

That is, it is possible to prevent dust and dirt generated when forming the groove 17a from adhering to the device 19. Further, unlike the case where the tape is attached to the region where the device 19 of the workpiece 11 is formed, the adhesive of the tape does not remain on the device 19. Therefore, according to the method for dividing the workpiece according to the present embodiment, the possibility that the device 19 is contaminated when the workpiece 11 is divided can be suppressed to a low level.

The present invention is not limited to the description of the above-described embodiment, and can be implemented with various modifications. For example, in the above-described embodiment, the workpiece 11 having the concave portion 13 whose shape is circular when viewed from the first surface 11a side is divided, but the shape seen from the first surface 11a side can be obtained by the same method. The workpiece 11 having the non-circular recess 13 can be divided.

Further, in the above-described embodiment, the cutting blade 8 provided with the cutting edge containing the abrasive grains is used to form the groove (starting point region) 17a as the starting point of the division on the planned division line 17 of the workpiece 11. By ablation processing that irradiates the second surface 11b side of the workpiece 11 with a laser beam having a wavelength absorbed by the workpiece 11, the groove (starting point region) that is the starting point of the division is formed into the planned division line of the workpiece 11. It can also be formed at 17 (starting point region forming step).

In this case, for example, a chuck table (vacuum chuck) having a substantially flat holding surface suitable for holding the workpiece 11, and a laser oscillator that generates a laser beam having a wavelength absorbed by the workpiece 11. A laser processing device including a laser processing unit including a condenser such as a lens for condensing a laser beam and a laser beam is used.

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

11: Work piece 11a: First surface (surface)
11b: Second side (back side)
13: Recessed portion 13a: Bottom surface 15: Reinforcing part 17: Scheduled division line 17a: Groove 19: Device 21: First tape 23: Second tape 31: Tip 2: Cutting device 4: Cutting unit 6: Spindle 8: Cutting blade

Claims (3)

A method for dividing a work piece, which is used when dividing a work piece including a recess in which a device is formed on a bottom surface partitioned by a planned division line and a ring-shaped reinforcing portion surrounding the recess.
A tape application step in which the first tape is attached to the reinforcing portion without contacting the bottom surface of the recess and the space inside the recess is sealed with the first tape.
A starting point region forming step of forming a starting point region, which is a starting point of division, from a surface side opposite to the first tape of the workpiece to which the first tape is attached to the reinforcing portion on the planned division line.
A tape reattachment step in which the second tape is attached to the surface side of the workpiece and the first tape is peeled off from the reinforcing portion.
A method for dividing a work piece, which comprises expanding the second tape and dividing the work piece from the starting point region. In the starting point region forming step, a cutting blade provided with a cutting blade containing abrasive grains is rotated to cut into the surface side of the work piece, and a groove serving as a starting point of division is formed in the planned division line. The method for dividing a work piece according to claim 1. The starting point region forming step is characterized in that a laser beam having a wavelength absorbed by the workpiece is irradiated on the surface side of the workpiece to form a groove as a starting point of division in the planned division line. The method for dividing a work piece according to claim 1.

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