JP2020113564A - Manufacturing method of chip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a chip capable of suppressing deterioration of the quality of the chip due to cracks. SOLUTION: This is a method of manufacturing a chip for manufacturing a chip by cutting a wafer on which a planned division line is set, a tape sticking step of sticking a dicing tape on the back surface side of the wafer, and a dicing tape and a chuck table. The wafer is placed on the chuck table so that the holding surface of the wafer is opposed to the holding surface of the wafer, and the cutting blade is cut into the wafer to a predetermined depth to form a cutting groove in the wafer and the cutting groove. It includes a first cutting step that causes a crack to reach the back surface of the wafer from the surface and a second cutting step that cuts the cutting blade into the groove bottom of the cutting groove, and occurs when the wafer is cut in the second cutting step. The crack progresses along the crack generated in the first cutting step. [Selection diagram] FIG. 4

Description

The present invention relates to a chip manufacturing method for manufacturing a chip by cutting a wafer.

A wafer in which devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in a plurality of areas divided by dividing lines (streets) set in a grid pattern is divided along the dividing lines. By doing so, a plurality of chips (device chips) including the device are manufactured. For example, a cutting device is used for dividing the wafer.

The cutting device includes a chuck table that holds a wafer, and a spindle (rotating shaft) on which an annular cutting blade that cuts the wafer is mounted. When the spindle is rotated with the cutting blade attached to the tip of the spindle, the cutting blade rotates. Then, the rotating cutting blade is cut into the wafer held by the chuck table to cut and divide the wafer.

Examples of wafers used for manufacturing chips include silicon wafers, wafers made of III-V group compound semiconductors such as GaAs, and sapphire wafers. However, when such a wafer is cut by a cutting blade and divided, a crack (chip) may occur on the back surface (lower surface) side of the wafer. If these cracks remain on the chips obtained by dividing the wafer, the quality of the chips deteriorates. Therefore, it is desirable to suppress the occurrence of cracks on the back surface side of the wafer as much as possible.

It has been confirmed that the shape (traveling direction) and the frequency of cracks generated by cutting the wafer depend on the crystal orientation of the wafer. Therefore, attempts have been made to suppress the occurrence of cracks by setting the direction of the dividing line based on the crystal orientation of the wafer (see Patent Documents 1 and 2, for example).

JP, 2007-242804, A JP, 2016-157872, A

The cracks generated on the back surface side of the wafer when the wafer is cut by the cutting blade are often not sufficiently reduced only by adjusting the direction of the planned dividing line as described above. For example, when the wafer to be cut by the cutting blade is a compound semiconductor wafer made of GaAs or the like, cracks are likely to occur, and in addition to adjusting the direction of the planned dividing line, the size of the abrasive grains contained in the cutting blade and Even if the cutting depth of the cutting blade is optimized, it may be difficult to sufficiently suppress the occurrence of cracks on the back surface side of the wafer.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a chip manufacturing method capable of suppressing deterioration of chip quality due to cracks.

According to one aspect of the present invention, there is provided a chip manufacturing method of manufacturing a chip by cutting a wafer in which a dividing line is set, and a tape bonding step of bonding a dicing tape to the back surface side of the wafer. A mounting step of mounting the wafer on the chuck table so that the dicing tape and the holding surface of the chuck table face each other after the tape attaching step, and a cutting blade after the mounting step. The cutting blade and the chuck table are relatively moved along the dividing line in a state where the lower end of the cutting blade is arranged below the front surface of the wafer and above the back surface of the wafer. A first cutting step for forming a cutting groove in the wafer by cutting the wafer at a predetermined depth and causing a crack reaching the back surface of the wafer from the cutting groove; and, after the first cutting step, The cutting blade and the chuck table are relatively moved along the cutting groove while the lower end of the cutting blade is arranged below the rear surface of the wafer and above the lower surface of the dicing tape, and the cutting is performed. A second cutting step of cutting a blade into the groove bottom of the cutting groove, wherein the crack generated when the wafer is cut in the second cutting step is the crack generated in the first cutting step. A method of manufacturing a chip that proceeds along is provided.

In addition, preferably, the wafer is a GaAs wafer. Further, preferably, in the second cutting step, the cutting blade is rotated in a direction in which the cutting blade cuts the wafer from the back surface side to the front surface side to cut the wafer.

A method of manufacturing a chip according to an aspect of the present invention, by cutting a cutting blade at a predetermined depth in the wafer, to form a cutting groove in the wafer and to generate a crack reaching the back surface of the wafer from the cutting groove It includes one cutting step and a second cutting step of cutting the cutting blade into the groove bottom of the cutting groove. Then, the crack generated when the wafer is cut in the second cutting step progresses along the crack generated in the first cutting step.

By using the above-described chip manufacturing method, it is possible to prevent a crack generated when the wafer is divided by the cutting blade from proceeding to the outside of the cutting groove. As a result, it is possible to prevent cracks from remaining in the chips obtained by dividing the wafer, and suppress deterioration of the chip quality.

It is a perspective view showing a cutting device. It is a perspective view which shows a wafer. It is sectional drawing which shows the cutting device which hold|maintains a wafer with a chuck table. FIG. 4(A) is a sectional view showing the cutting device in the first cutting step, and FIG. 4(B) is an enlarged sectional view showing a part of the wafer in the first cutting step. It is sectional drawing which shows the cutting device which cuts a wafer by down-cut. FIG. 6(A) is a sectional view showing the cutting device in the second cutting step, and FIG. 6(B) is an enlarged sectional view showing a part of the wafer in the second cutting step. It is sectional drawing which shows the cutting device which cuts a wafer by up-cut.

Embodiments according to one aspect of the present invention will be described below with reference to the accompanying drawings. First, a configuration example of a cutting device that can be used in the method for manufacturing a chip according to this embodiment will be described. FIG. 1 is a perspective view showing the cutting device 2.

The cutting device 2 includes a base 4 that supports the respective constituent elements of the cutting device 2. An opening 4a is formed at a front corner of the base 4, and a cassette support 6 that moves in the Z-axis direction (vertical direction, vertical direction) by a lifting mechanism (not shown) is formed inside the opening 4a. It is provided. A cassette 8 capable of accommodating a plurality of wafers 11 to be cut by the cutting device 2 is mounted on the upper surface of the cassette support base 6. In FIG. 1, the outline of the cassette 8 is indicated by a chain double-dashed line.

FIG. 2 is a perspective view showing the wafer 11. The wafer 11 is formed in a disk shape using, for example, a compound semiconductor such as GaAs, and has a front surface 11a and a back surface 11b. In this embodiment, a GaAs wafer made of GaAs single crystal is used as the wafer 11.

The wafer 11 is divided into a plurality of regions by dividing lines (streets) 13 which are set in a grid pattern so as to intersect with each other, and IC (Integrated Circuit) and LSI (Large) are provided on the front surface 11a side of these regions, respectively. A device 15 including a Scale Integration), an LED (Light Emitting Diode), and the like is formed.

The material, shape, structure, size, etc. of the wafer 11 are not limited. For example, the wafer 11 may be a wafer of any shape made of a material other than GaAs such as semiconductors (Si, InP, GaN, SiC, etc.), sapphire, glass, ceramics, resin, metal and the like. Further, there is no limitation on the type, quantity, shape, structure, size, arrangement, etc. of the device 15.

On the back surface 11b side of the wafer 11, a circular dicing tape (adhesive tape) 17 having a diameter larger than that of the wafer 11 is attached. For example, the dicing tape 17 is a flexible film obtained by forming a rubber-based or acrylic-based adhesive layer (paste layer) on a substrate made of a resin such as polyolefin, polyvinyl chloride, or polyethylene terephthalate.

The outer peripheral portion of the dicing tape 17 is attached to an annular frame 19 having a circular opening 19a having a diameter larger than that of the wafer 11 in the central portion. Therefore, the wafer 11 is supported by the frame 19 via the dicing tape 17 while being arranged inside the opening 19a. Then, the wafer 11 is accommodated in the cassette 8 shown in FIG. 1 while being supported by the frame 19.

Behind the opening 4a, a transfer unit (transfer mechanism) 10 that carries out the wafer 11 from the cassette 8 and carries the wafer 11 into the cassette 8 is provided. The transport unit 10 is configured to be movable along the Y-axis direction (indexing feed direction, front-back direction). Further, a grip portion 10 a that grips the end portion of the frame 19 that supports the wafer 11 is provided at the end portion of the transport unit 10 that is located on the cassette 8 side.

A temporary placement area 12 is provided between the cassette 8 and the transport unit 10 to temporarily place the wafer 11 unloaded from the cassette 8 or the wafer 11 loaded into the cassette 8. The temporary placement area 12 is provided with a pair of guide rails 14 arranged substantially parallel to each other along the Y-axis direction. The pair of guide rails 14 move so as to approach and separate from each other along the X-axis direction (processing feed direction, left-right direction).

A transport unit (transport mechanism) 16 that suctions and holds the frame 19 that supports the wafer 11 and transports the wafer 11 is provided near the temporary placement area 12. A chuck table 18 for holding the wafer 11 is provided on the side of the cassette 8.

The chuck table 18 is connected to a rotary drive source (not shown) such as a motor, and rotates about a rotation axis substantially parallel to the Z-axis direction. A moving mechanism (not shown) is provided below the chuck table 18, and this moving mechanism moves the chuck table 18 along the X-axis direction. Further, around the chuck table 18, four clamps 20 for fixing the frame 19 supporting the wafer 11 from four sides are provided.

The upper surface of the chuck table 18 constitutes a holding surface 18 a that holds the wafer 11. The holding surface 18a is connected to a suction source (not shown) via a suction path (not shown) formed inside the chuck table 18.

When processing the wafer 11, first, the frame 19 supporting the wafer 11 accommodated in the cassette 8 is gripped by the grip portion 10 a of the transport unit 10. When the transport unit 10 is moved backward along the Y-axis direction in this state, the wafer 11 is pulled out from the cassette 8. The wafer 11 thus unloaded from the cassette 8 is temporarily placed in the temporary placement area 12.

The pair of guide rails 14 provided in the temporary placement area 12 move along the X-axis direction so as to approach each other while supporting the frame 19 supporting the wafer 11. As a result, the frame 19 is sandwiched by the pair of guide rails 14, and the wafer 11 is aligned. Thereafter, the wafer 11 is suction-held by the transfer unit 16 and transferred onto the chuck table 18.

A cutting unit 22 that cuts the wafer 11 held by the chuck table 18 is provided above the chuck table 18. The cutting unit 22 includes a spindle 42 (see FIG. 3) on which a ring-shaped cutting blade 44 (see FIG. 3) for cutting the wafer 11 is mounted on the tip portion. Further, the cutting unit 22 is connected to a moving mechanism (not shown), and this moving mechanism moves the cutting unit 22 along the Y-axis direction and the Z-axis direction.

Further, the cutting unit 22 includes a nozzle (not shown) for supplying a cutting liquid such as pure water. When the wafer 11 is cut by the cutting unit 22, the cutting liquid is supplied to the wafer 11 and the cutting blade 44 (see FIG. 3) from this nozzle. As a result, the wafer 11 and the cutting blade 44 are cooled, and debris (cutting debris) generated by cutting is washed away.

The cutting device 2 also includes a cover 24 that covers a processing space in which the wafer 11 is processed by the cutting unit 22. The cover 24 is provided so as to cover the front and upper sides of the cutting unit 22. When the wafer 11 is processed by the cutting unit 22, by covering the chuck table 18 and the cutting unit 22 with the cover 24, it is possible to prevent the cutting fluid and the processing waste from scattering outside the processing space. Since the cover 24 is locked in the closed state during the processing of the wafer 11, the exposure of the wafer 11 and the cutting unit 22 is prevented, and the processing is performed safely.

A detection unit (detection mechanism) 26 that detects the position of the planned dividing line 13 set on the wafer 11 is provided above the movement path of the chuck table 18. The detection unit 26 includes an image pickup unit 28 including a camera for picking up an image of the wafer 11 held by the chuck table 18. Based on the image of the wafer 11 acquired by the imaging unit 28, the wafer 11 held by the chuck table 18 and the cutting unit 22 are aligned with each other.

A cleaning unit 30 for cleaning the wafer 11 is provided behind the chuck table 18. A transfer unit (transfer mechanism) 32 that transfers the wafer 11 from the chuck table 18 to the cleaning unit 30 is provided above the cleaning unit 30.

When the processing of the wafer 11 by the cutting unit 22 is completed, the wafer 11 is transferred from the chuck table 18 to the cleaning unit 30 by the transfer unit 32, and the cleaning and drying of the wafer 11 by the cleaning unit 30 are performed. After that, the wafer 11 is transferred onto the pair of guide rails 14 by the transfer unit 16 and then stored in the cassette 8 by the transfer unit 10.

A display unit 34 that displays an image captured by the image capturing unit 28, various types of information referred to by an operator, and the like is provided above the cutting device 2. Further, on the front side of the base 4, an operation panel 36 is provided for the operator to input information such as processing conditions.

A plurality of chips (device chips) each including a device 15 are manufactured by cutting the wafer 11 along the dividing line 13 (see FIG. 2) by using the above cutting device 2 and dividing the wafer 11. Hereinafter, a specific example of the method of manufacturing the chip according to this embodiment will be described.

First, as shown in FIG. 2, the dicing tape 17 is attached to the back surface 11b side of the wafer 11 (tape attaching step). Then, the wafer 11 to which the dicing tape 17 is attached is housed in the cassette 8 (see FIG. 1), and the cassette 8 is placed on the cassette support base 6.

Next, the wafer 11 is mounted on the chuck table 18 (mounting step). Specifically, first, the wafer 11 accommodated in the cassette 8 is pulled out by the transfer unit 10 and transferred to the temporary placement area 12. After that, the wafer 11 is aligned with the pair of guide rails 14, and then the wafer 11 is placed on the chuck table 18 by the transfer unit 16.

FIG. 3 is a cross-sectional view showing the cutting device 2 that holds the wafer 11 by the chuck table 18. The wafer 11 is placed on the chuck table 18 so that the dicing tape 17 attached to the back surface 11b side of the wafer 11 and the holding surface 18a of the chuck table 18 face each other. Further, the frame 19 supporting the wafer 11 is fixed by the clamp 20.

When a negative pressure of a suction source is applied to the holding surface 18a in this state, the wafer 11 is suction-held by the chuck table 18 with the front surface 11a side exposed upward. Then, the chuck table 18 holding the wafer 11 is positioned below the cutting unit 22.

The cutting unit 22 includes a tubular housing 40 fixed to a moving mechanism (not shown) that controls the position of the cutting unit 22 in the Y-axis direction and the Z-axis direction. Inside the housing 40, a spindle 42 arranged substantially parallel to the Y-axis direction and functioning as a rotation shaft is accommodated. A tip portion on one end side of the spindle 42 is exposed to the outside of the housing 40, and an annular cutting blade 44 for cutting the wafer 11 is attached to this tip portion.

The material of the cutting blade 44 is not limited. For example, as the cutting blade 44, an electroformed hub blade having an annular cutting edge formed by fixing abrasive grains made of diamond or the like with a plating layer made of nickel or the like, or an abrasive grain made of metal, ceramics, resin or the like is used. A washer type blade or the like is used, which is composed of an annular cutting blade fixed and formed with a bond material.

The other end of the spindle 42 is connected to a rotary drive source (not shown) such as a motor. The cutting blade 44 attached to the tip of the spindle 42 rotates by the power of the rotary drive source transmitted via the spindle 42.

Next, a cutting groove is formed in the wafer 11 by cutting the cutting blade 44 into the wafer 11 at a predetermined depth (first cutting step). FIG. 4A is a sectional view showing the cutting device 2 in the first cutting step, and FIG. 4B is an enlarged sectional view showing a part of the wafer 11 in the first cutting step.

In the first cutting step, first, the chuck table 18 is rotated so that the length direction of one division line 13 (see FIG. 2) is aligned with the machining feed direction (X axis direction) of the cutting device 2. Further, the height of the cutting unit 22 is adjusted so that the lower end of the cutting blade 44 is arranged below the front surface 11a of the wafer 11 and above the back surface 11b of the wafer 11. Further, the position of the cutting unit 22 in the indexing feed direction (Y-axis direction) is adjusted so that the cutting blade 44 is arranged on the extension line of the one planned dividing line 13.

After that, the chuck table 18 is moved along the machining feed direction while rotating the cutting blade 44. As a result, the chuck table 18 and the cutting unit 22 move relative to each other along the planned dividing line 13, and the cutting blade 44 moves along the planned dividing line 13 to the wafer 11 at a predetermined depth (cutting depth D, FIG. 4 (see (B)). As a result, the wafer 11 is cut, and a linear cutting groove 11c having a depth less than the thickness of the wafer 11 is formed along the dividing line 13 on the surface 11a side of the wafer 11.

If the cutting blade 44 is cut at a depth exceeding the thickness of the wafer 11 to divide the wafer 11 in the first cutting step, the back surface 11b of the wafer 11 is cracked so as to protrude from the cut edge (kerf). Chips may be formed. If this crack remains on the chip obtained by dividing the wafer 11, the quality of the chip deteriorates.

In particular, it has been confirmed that when the cutting blade 44 is cut to a depth exceeding the thickness of the wafer 11 when the wafer 11 is a GaAs wafer, cracks are likely to occur on the back surface 11b of the wafer 11. This phenomenon is considered to be due to the properties such as hardness and brittleness of the GaAs wafer, and the progress direction of cracks generated during cutting depending on the crystal orientation of GaAs. Specifically, it has been confirmed that a GaAs wafer has a direction in which cracks easily progress and a direction in which cracks do not easily progress depending on the crystal orientation of GaAs.

When the planned dividing line 13 is set so as to intersect with the direction in which the crack easily progresses, when the wafer 11 is cut along the planned dividing line 13, the crack advances toward the outside of the planned dividing line 13 and is divided. It is easy to stick out from the scheduled line 13. On the other hand, if the planned dividing line 13 is set along the direction in which the crack easily advances, it is expected that the crack will not easily protrude from the planned dividing line 13.

However, as shown in FIG. 2, the planned dividing lines 13 are set in a grid pattern along the two directions, and it is difficult to set all the dividing lines 13 along the direction in which cracks easily progress. Therefore, when the wafer 11 is cut, it is desired that the traveling direction of cracks be controlled without being affected by the crystal orientation of the wafer 11.

Therefore, in the present embodiment, first, in the first cutting step, the cutting blade 44 is cut into the vicinity of the back surface 11b of the wafer 11 to form the cutting groove 11c. That is, the wafer 11 is not cut in the first cutting step. As a result, as shown in FIG. 4B, an uncut portion 11e corresponding to a region where the cutting groove 11c is not formed is formed on the back surface 11b side of the wafer 11. In FIG. 4B, the thickness of the uncut portion 11e is indicated by T.

When the wafer 11 is cut by the cutting blade 44 in this way, the crack 21 is formed in the uncut portion 11e due to the load (processing load) applied to the wafer 11 when the cutting blade 44 cuts into the wafer 11. The crack 21 progresses in the direction in which the cutting blade 44 cuts into the wafer 11, that is, from the groove bottom 11d of the cutting groove 11c toward the lower side, and reaches a region overlapping the cutting groove 11c on the back surface 11b of the wafer 11.

Therefore, when the cutting groove 11c is formed on the wafer 11, a position on the back surface 11b of the wafer 11 that overlaps with the cutting groove 11c is along an area inside the planned dividing line 13 (an area corresponding to between the adjacent devices 15). A linear crack is formed.

The cutting depth D of the cutting blade 44 in the first cutting step is based on the material of the wafer 11 and the cutting blade 44, the rotation speed of the cutting blade 44, and the like, and the crack 21 generated inside the cutting groove 11c is It is adjusted to reach the back surface 11b. For example, when a GaAs wafer having a thickness of 400 μm is used as the wafer 11, the cutting blade 44 is formed so that the thickness T of the uncut portion 11e is 10 μm or less, that is, the cutting depth D of the cutting blade 44 is 390 μm or more. It was confirmed that the crack 21 was appropriately formed by cutting into 11.

However, in the case where the thickness T of the uncut portion 11e is particularly small, in addition to the crack 21, the region on the back surface 11b of the wafer 11 outside the cutting groove 11c from the inside of the cutting groove 11c (a region that does not overlap with the cutting groove 11c). ) Can form cracks. Therefore, the thickness T of the uncut portion 11e is preferably set so that only the crack 21 is formed. For example, when a GaAs wafer is used as the wafer 11, the thickness of the uncut portion 11e is preferably 5 μm or more, that is, the cutting depth D of the cutting blade 44 is preferably 395 μm or less.

After that, the same procedure is repeated to form the cutting grooves 11c along all the planned dividing lines 13. As a result, lattice-shaped cutting grooves 11c are formed on the front surface 11a side of the wafer 11 along the planned dividing line 13. Further, lattice-shaped cracks are formed in the back surface 11b of the wafer 11 at positions overlapping the cutting grooves 11c.

In the first cutting step, it is preferable to cut the wafer 11 by so-called down-cutting, in which the cutting blade 44 is rotated in a direction in which the cutting blade 44 cuts the wafer 11 from the front surface 11a side to the back surface 11b side. FIG. 5 is a cross-sectional view showing a cutting device 2 that cuts the wafer 11 by down-cutting.

When the chuck table 18 is moved in the direction indicated by the arrow B while the cutting blade 44 is rotated in the direction indicated by the arrow A (counterclockwise in FIG. 5) to perform the processing feed, the cutting blade 44 causes the wafer 11 to move to the surface 11a. From the side toward the back surface 11b. By cutting the wafer 11 by down-cutting in the first cutting step, the crack 21 easily advances from the groove bottom 11d of the cutting groove 11c toward the back surface 11b of the wafer 11.

However, the cutting of the wafer 11 in the first cutting step is not limited to the above method. That is, the wafer 11 may be cut by so-called up-cut (see FIG. 7) in which the cutting blade 44 rotates the cutting blade 44 in a direction that cuts the wafer 11 from the back surface 11b side to the front surface 11a side.

Next, the cutting blade 44 is cut into the groove bottom 11d of the cutting groove 11c (second cutting step). FIG. 6A is a sectional view showing the cutting device 2 in the second cutting step, and FIG. 6B is an enlarged sectional view showing a part of the wafer 11 in the second cutting step.

In the second cutting step, first, the chuck table 18 is rotated to align the length direction of the one cutting groove 11c with the machining feed direction (X axis direction) of the cutting device 2. Further, the height of the cutting unit 22 is adjusted so that the lower end of the cutting blade 44 is arranged below the back surface 11b of the wafer 11 and above the lower surface of the dicing tape 17. Further, the position of the cutting unit 22 in the indexing feed direction (Y-axis direction) is adjusted so that the cutting blade 44 is arranged on the extension line of the one cutting groove 11c.

After that, the chuck table 18 is moved along the machining feed direction while rotating the cutting blade 44. As a result, the chuck table 18 and the cutting unit 22 relatively move along the cutting groove 11c, and the cutting blade 44 cuts into the groove bottom 11d of the cutting groove 11c. As a result, the wafer 11 is divided along the cutting groove 11c. At this time, since the dicing tape 17 is not cut, the disposition of the wafer 11 after the division is maintained by the dicing tape 17.

When the cutting blade 44 is cut into the groove bottom 11d of the cutting groove 11c, a crack (not shown) is generated from the contact region between the cutting blade 44 and the wafer 11. If the crack progresses to the outside of the cutting groove 11c, the crack may remain in the chip obtained by dividing the wafer 11, and the quality of the chip may deteriorate.

In the present embodiment, a crack 21 extending from the cutting groove 11c to the back surface 11b of the wafer 11 is formed by performing the first cutting step, and the crack 21 reaches a region of the back surface 11b of the wafer 11 overlapping the cutting groove 11c. ing. When the second cutting step is performed in this state, the crack generated in the contact area between the cutting blade 44 and the wafer 11 is guided to the crack 21 and progresses along the crack 21. Therefore, it is possible to prevent a crack generated when the wafer 11 is cut from proceeding to the outside of the cutting groove 11c.

Then, the same procedure is repeated, and the wafer 11 is cut along all the planned dividing lines 13. As a result, the wafer 11 is divided into a plurality of regions divided by the division line 13, and a plurality of chips each including the device 15 (see FIG. 2) are manufactured. These chips are mounted in various electronic devices represented by, for example, personal computers and mobile phones.

In the second cutting step, it is preferable to cut the wafer 11 by so-called up-cut, in which the cutting blade 44 is rotated in a direction in which the cutting blade 44 cuts the wafer 11 from the back surface 11b side to the front surface 11a side. FIG. 7 is a cross-sectional view showing a cutting device 2 that cuts the wafer 11 by up-cutting.

When the chuck blade 18 is moved in the direction indicated by the arrow D to perform the processing feed while rotating the cutting blade 44 in the direction indicated by the arrow C (clockwise in FIG. 7), the cutting blade 44 causes the wafer 11 to move to the back surface 11b side. To the surface 11a side. When the down cutting is performed in the first cutting step and the up cutting is performed in the second cutting step, instead of changing the rotation direction of the cutting blade 44 (arrow A in FIG. 5, arrow C in FIG. 7), the machining feed is changed. It is also possible to switch between downcut and upcut by changing the direction (arrow B in FIG. 5, arrow D in FIG. 7).

It was confirmed that when the wafer 11 was cut by the up-cut as described above in the second cutting step, the residual cracks on the back surface 11b side of the wafer 11 were more effectively reduced. From this result, when the wafer 11 is cut by the up-cut, the cracks generated in the contact region between the wafer 11 and the cutting blade 44 are more likely to progress along the cracks 21 than the down-cut, and are advanced to the outside of the cutting groove 11c. It is presumed that it will become difficult.

As described above, in the method of manufacturing a chip according to the present embodiment, the cutting blade 44 is cut into the wafer 11 at a predetermined depth to form the cutting groove 11c in the wafer 11 and to cut the wafer 11 from the cutting groove 11c. It includes a first cutting step for generating the crack 21 reaching the back surface 11b and a second cutting step for cutting the cutting blade 44 into the groove bottom 11d of the cutting groove 11c. Then, the crack generated when the wafer 11 is cut in the second cutting step progresses along the crack 21 generated in the first cutting step.

By using the chip manufacturing method described above, it is possible to prevent a crack generated when the wafer 11 is divided by the cutting blade 44 from proceeding to the outside of the cutting groove 11c. As a result, it is possible to prevent cracks from remaining in the chips obtained by dividing the wafer 11 and suppress deterioration of the chip quality.

In addition, in this embodiment, the case where all the cracks 21 formed in the first cutting step are formed so as to reach a region overlapping the cutting groove 11c of the back surface 11b of the wafer 11 has been described. However, for example, some cracks 21 may slightly protrude to the outside of the cutting groove 11c as long as there is no problem in the quality of the chips obtained by dividing the wafer 11.

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

11 wafer 11a front surface 11b back surface 11c cutting groove 11d groove bottom 11e uncut portion 13 planned dividing line (street)
15 Device 17 Dicing tape (adhesive tape)
19 frame 19a opening 21 crack 2 cutting device 4 base 4a opening 6 cassette support 8 cassette 10 transfer unit (transfer mechanism)
10a Grip 12 Temporary Placement Area 14 Guide Rail 16 Transport Unit (Transport Mechanism)
18 Chuck Table 18a Holding Surface 20 Clamp 22 Cutting Unit 24 Cover 26 Detection Unit (Detection Mechanism)
28 Imaging Unit 30 Cleaning Unit 32 Transport Unit (Transport Mechanism)
34 Display 36 Operation Panel 40 Housing 42 Spindle 44 Cutting Blade

Claims (3)

A chip manufacturing method of manufacturing a chip by cutting a wafer in which a dividing line is set,
A tape attaching step of attaching a dicing tape to the back surface side of the wafer,
A mounting step of mounting the wafer on the chuck table such that the dicing tape and the holding surface of the chuck table face each other after the tape attaching step;
After the placing step, the cutting blade and the chuck table are arranged along the dividing line in a state where the lower end of the cutting blade is arranged below the front surface of the wafer and above the back surface of the wafer. A first cutting step in which a cutting groove is formed in the wafer by moving the cutting blade relative to each other and cutting the cutting blade into the wafer at a predetermined depth, and a crack reaching the back surface of the wafer from the cutting groove is generated; ,
After the first cutting step, the cutting blade and the chuck table are placed in the cutting groove while the lower end of the cutting blade is arranged below the back surface of the wafer and above the lower surface of the dicing tape. A second cutting step in which the cutting blade is moved relative to the cutting blade to cut into the groove bottom of the cutting groove,
A method for manufacturing a chip, wherein a crack generated when the wafer is cut in the second cutting step progresses along the crack generated in the first cutting step. The method of manufacturing a chip according to claim 1, wherein the wafer is a GaAs wafer. In the second cutting step, the wafer is cut by rotating the cutting blade in a direction in which the cutting blade cuts the wafer from the back surface side toward the front surface side. A method for manufacturing the described chip.

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