JP7286238B2 - How to make multiple chips - Google Patents

Description

The present invention relates to a method of manufacturing a plurality of chips by processing a plate-like workpiece.

As a method of dividing a workpiece such as a disk-shaped wafer with devices etc. formed on the surface side along the planned dividing line, a modified layer having a lower strength than other regions is formed along the planned dividing line. A method is known in which an external force is applied to the workpiece after it has been processed (see, for example, Patent Document 1).

In order to form the modified layer, for example, a pulsed laser beam having a wavelength that is transmissive to the wafer is positioned inside the wafer, so that a laser beam is emitted along the dividing line of the wafer. to irradiate. As a result, multiphoton absorption occurs in the vicinity of the focal point inside the wafer, and a modified layer with reduced mechanical strength is formed along the dividing line.

By the way, in order to split a relatively thick wafer of, for example, more than 100 μm along splitting lines, it is usually necessary to form a plurality of modified layers so as to overlap each other in the depth direction of the wafer. For example, when forming three modified layers so as to overlap each other in the depth direction of the wafer, a laser beam is emitted along the dividing line while the depth position of the focal point is positioned at the first depth position. Irradiate (first pass).

Next, while the depth position of the focal point is positioned at a second depth position closer to the surface side than the first depth position, a laser beam is irradiated along the line to be divided (second pass ). Furthermore, while the depth position of the focal point is positioned at a third depth position closer to the surface side than the second depth position, the laser beam is again irradiated along the line to be divided (third depth position). path).

As described above, the method of forming the modified layer usually requires a plurality of passes of laser beam irradiation along the line to be divided, which causes the problem that the processing takes time. Therefore, as a processing method with a reduced number of passes, a method has been proposed in which a modified region called a shield tunnel having pores and modified regions surrounding the pores is formed along the dividing line of the wafer (for example, See Patent Document 2).

When the shield tunnel is formed along the dividing line, the value (S (=NA/N)) obtained by dividing the numerical aperture (NA) by the refractive index (N) of the wafer is, for example, 0.05 or more and 0.2. The laser beam is focused using the following focusing lens. After setting the S value in this manner, the condensing region of the pulsed laser beam having a wavelength that is transparent to the wafer is positioned inside the wafer.

For example, one shield tunnel extending from the front surface to the back surface of the wafer can be formed by irradiating one pulse of the laser beam from the rear surface side of the wafer with the focusing region positioned at a predetermined depth of the wafer. Therefore, if a plurality of pulses of the laser beam is irradiated along the line to be divided by positioning the condensing area at a predetermined depth position (i.e., by irradiating one pass of the laser beam), a plurality of laser beams can be obtained along the line to be divided. of shield tunnels are formed.

In this way, if a plurality of shield tunnels are formed along the line to be split by irradiating a single pass of the laser beam, processing becomes easier compared to the case where a plurality of modified layers are formed so as to overlap in the thickness direction of the wafer. There is an advantage that the time required for the process can be reduced.

Japanese Patent Application Laid-Open No. 2002-192367 JP 2014-221483 A

As a method for surely dividing a wafer in which a plurality of shield tunnels are formed along the dividing line, for example, a stretchable resin sheet is attached to the front side of the wafer, and this sheet is stretched in the radial direction of the wafer. There is a way to pull The wafer is split by being pulled radially outward together with the sheet.

Further, for example, as a method for reliably dividing a wafer in which a plurality of shield tunnels are formed along the planned division lines, there is a method of applying a load to the wafer by pressing a pressing member such as a break blade against the planned division lines. . The wafer is split by the stress applied in the thickness direction along the split lines.

However, when dividing the workpiece by applying only tensile stress or load stress to the wafer (i.e., the workpiece) in which a plurality of shield tunnels are formed, the workpiece cannot be divided. On the other hand, it is necessary to apply a certain amount of stress in order to divide it reliably. Therefore, there is a high possibility that processing defects such as chipping and cracks will occur in the workpiece.

The present invention has been made in view of such problems, and when dividing a workpiece in which a plurality of shield tunnels are formed along a line to be divided, stress due to tensile stress and load is applied to the workpiece. It is an object of the present invention to provide a chip manufacturing method capable of reducing the possibility of defective processing as compared with the case where a workpiece is divided by applying only a voltage.

According to one aspect of the present invention, a plurality of chips are manufactured by dividing a workpiece having a plurality of regions on the surface side partitioned by a plurality of intersecting dividing lines along the dividing lines. In the method, a stretchable tape is attached to the workpiece and the annular frame , so that the workpiece is placed in the opening of the annular frame, and the tape is applied to the workpiece. affixing a work piece to form a work piece unit integrated with the annular frame; A plurality of shields each having a pore and an altered region surrounding the pore by irradiating the laser beam along each division line from the back side of the work so as to be positioned inside the work. a shield tunnel forming step of forming a tunnel along each planned dividing line ; By adjusting the height position of by expanding and contracting the plurality of legs, the workpiece unit is positioned at a position lower than the water level of the liquid filled from the bottom of the container to a predetermined height position By applying ultrasonic waves to the work piece through the liquid and expanding the tape with a push-up device that pushes the tape from below , the work piece is along the plurality of planned division lines. a dividing step of dividing the .

Preferably, in the dividing step, the work piece is divided along the plurality of planned division lines by expanding the tape while applying ultrasonic waves to the work piece through a liquid. In addition, preferably, the application of the ultrasonic waves in the dividing step is performed by adjusting the height position of the workpiece unit with the plurality of legs, thereby obtaining a predetermined position at which the ultrasonic waves are easily transmitted in the liquid. adjusting the height position of the workpiece to the height position of

In the method for manufacturing a plurality of chips according to one aspect of the present invention, after the shield tunnels are formed along the planned division lines of the workpiece in the shield tunnel forming step, ultrasonic waves are applied to the workpiece through the liquid. to divide the workpiece by expanding the stretchable tape attached to the workpiece.

In this way, in the dividing step of the present invention, not only tensile stress is applied to the work piece via the tape, but also ultrasonic waves are applied to the work piece, thereby promoting breakage of the shield tunnel. Therefore, since the work piece can be divided even if the tensile stress is reduced, the possibility of defective processing is reduced compared to the case where the work piece is divided by applying only the tensile stress to the work piece. can be reduced.

FIG. 1A is a perspective view of a workpiece, and FIG. 1B is a perspective view of a workpiece unit. 1 is a perspective view of a laser processing device; FIG. FIG. 3A is a partial cross-sectional side view of a workpiece, etc., when the machining head and the chuck table are moved relative to each other, and FIG. It is a partial cross section side view, such as a to-be-processed object after making it move to. FIG. 4(A) is a perspective view showing the structure of one shield tunnel, and FIG. 4(B) is a partial cross-section of the workpiece showing a plurality of shield tunnels formed along the line to be split. It is a diagram. FIG. 5A is a partial cross-sectional side view of an ultrasonic wave applying device and the like, and FIG. 5B is a diagram showing how ultrasonic waves are applied to a workpiece through liquid. (C) is a diagram showing how the dicing tape is expanded while applying ultrasonic waves to the workpiece through the liquid. 1 is a flow diagram illustrating a method of manufacturing multiple chips according to the first embodiment; FIG. FIG. 7A is a partial cross-sectional side view of an ultrasonic wave applying device and the like, FIG. 7B is a partial cross-sectional side view of a dividing device and the like, and FIG. 7C is a dividing device. It is a figure which shows a mode that a dicing tape is extended using.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. FIG. 1A is a perspective view of the workpiece 11. FIG. The workpiece 11 is a disk-shaped wafer having a circular front surface 11a and a circular rear surface 11b and a thickness of about 500 μm to 1000 μm.

The workpiece 11 is made of, for example, sapphire, various types of glass, or the like. Various types of glass include, for example, quartz glass, borosilicate glass, aluminosilicate glass, soda-lime glass, and alkali-free glass. Moreover, the workpiece 11 may be formed of a semiconductor material such as silicon (Si).

On the surface 11a side of the workpiece 11, a plurality of division lines (street) 13 are set so as to intersect each other (for example, in a grid pattern). In this embodiment, a device 15 is provided in each of a plurality of areas partitioned by a plurality of planned dividing lines 13 . However, the device 15 is not essential. The device 15 may not be provided in each of the rectangular regions partitioned by the dividing lines 13 arranged in a grid pattern.

Outside the device region 15a, there is an outer peripheral surplus region 15b in which no device 15 is provided so as to surround the outer periphery of the device region 15a in which the plurality of devices 15 are provided. A notch 11c indicating the crystal orientation of the wafer is provided in a part of the outer peripheral edge of the workpiece 11. As shown in FIG. Note that other marks such as an orientation flat may be provided instead of the notch 11c.

The workpiece 11 is machined in a state of being fixed to the opening of the metal annular frame 19 via, for example, a dicing tape 17 (that is, the workpiece unit 21 state). FIG. 1B is a perspective view of the workpiece unit 21. FIG.

The dicing tape 17 is a stretchable resin film. The dicing tape 17 has a laminated structure of an adhesive layer (not shown) having adhesiveness and a base layer (not shown) having no adhesiveness. The adhesive layer is, for example, an ultraviolet curable resin layer, and is provided on the entire surface of the base layer made of resin. When the adhesive layer is irradiated with ultraviolet rays, the adhesive strength of the adhesive layer is lowered, and the protective tape is easily peeled off from the workpiece 11 .

The annular frame 19 has an opening with a diameter larger than the diameter of the workpiece 11 . The workpiece unit 21 is formed by attaching the adhesive layer side of the dicing tape 17 to the front surface 11a side of the workpiece 11 and one surface of the annular frame 19 while the workpiece 11 is placed in the opening. be done.

In this embodiment, the laser processing device 2 is used to process the workpiece 11 . FIG. 2 is a perspective view of the laser processing device 2. FIG. The laser processing device 2 includes a base 4 that supports each structure. The base 4 includes a rectangular parallelepiped base 6 and a wall protruding upward (eg, +Z direction) at one end (eg, -Y direction) of the base 6 in the Y-axis direction (index feed direction). 8 and

A chuck table 10 is arranged above the base 6 . A plurality of clamp units are fixed to the outer peripheral side surface of the chuck table 10 . For example, when the chuck table 10 is viewed from above, one clamp unit is provided at each position of 0 o'clock, 3 o'clock, 6 o'clock and 9 o'clock.

A Y-axis moving unit 16 for moving the chuck table 10 in the Y-axis direction is provided below the chuck table 10 (for example, in the -Z direction). The Y-axis movement unit 16 includes a pair of Y-axis guide rails 18 fixed to the upper surface of the base 6 and parallel to the Y-axis direction.

A Y-axis moving table 20 is slidably installed on the Y-axis guide rail 18 . A nut portion (not shown) is provided on the back side (lower side) of the Y-axis moving table 20, and a Y-axis ball screw 22 arranged parallel to the Y-axis guide rail 18 rotates on this nut portion. combined in any possible manner.

A Y-axis pulse motor 24 is connected to one end of the Y-axis ball screw 22 . When the Y-axis ball screw 22 is rotated by the Y-axis pulse motor 24, the Y-axis moving table 20 moves along the Y-axis guide rail 18 in the Y-axis direction.

An X-axis movement unit 26 that moves the chuck table 10 in the X-axis direction (processing feed direction) orthogonal to the Y-axis direction is provided on the surface side (upper surface side) of the Y-axis movement table 20 . The X-axis moving unit 26 includes a pair of X-axis guide rails 28 fixed to the upper surface of the Y-axis moving table 20 and parallel to the X-axis direction.

An X-axis moving table 30 is slidably installed on the X-axis guide rail 28 . A nut portion (not shown) is provided on the back side (lower side) of the X-axis moving table 30, and an X-axis ball screw 32 arranged in parallel with the X-axis guide rail 28 rotates on this nut portion. combined in any possible manner.

An X-axis pulse motor 34 is connected to one end of the X-axis ball screw 32 . When the X-axis ball screw 32 is rotated by the X-axis pulse motor 34, the X-axis moving table 30 moves along the X-axis guide rail 28 in the X-axis direction.

A support base 36 is provided on the surface side (upper surface side) of the X-axis moving table 30 . A substantially disk-shaped chuck table 10 is arranged above the support table 36 . The chuck table 10 is connected to a rotation drive source (not shown) provided below, and is configured to be rotatable by this rotation drive source.

A disk-shaped porous plate made of porous ceramics or the like is provided on the front side of the chuck table 10 . The porous plate is connected to a suction source (not shown) such as an ejector through a channel (not shown) provided inside the chuck table 10 . Due to the negative pressure generated by the suction source, a suction force is generated on the surface of the porous plate (that is, the holding surface 10a).

A laser beam irradiation unit 12 is provided above the chuck table 10 . One end of the laser beam irradiation unit 12 is fixed to the upper surface of the wall portion 8 in the other Y-axis direction (eg, +Y direction).

A processing head 12 a is provided at the other end of the laser beam irradiation unit 12 . A pulsed laser beam is emitted from the processing head 12a substantially vertically toward the holding surface 10a.

An imaging unit 12b is provided on one side (−X direction) of the laser beam irradiation unit 12 in the X-axis direction. The imaging unit 12b has an objective lens (not shown) into which reflected light from a subject is incident. Reflected light from the subject is guided to an imaging device (not shown) of the imaging unit 12b via an objective lens or the like.

Next, FIG. 1(B), FIG. 3(A), FIG. 3(B), FIG. 4(A), FIG. 4(B), FIG. 5(A), FIG. 5(B), FIG. 5(C) and FIG. 6, a method of manufacturing a chip will be described. FIG. 6 is a flow diagram illustrating a method of manufacturing multiple chips according to the first embodiment.

In the chip manufacturing method according to the first embodiment, first, as shown in FIG. A unit 21 is formed (attachment step (S10)).

In the sticking step (S10), a tape sticking device (not shown) is used. The taping device includes a support table (not shown) that supports the workpiece 11 and the annular frame 19 . A stepped structure corresponding to the difference between the thickness of the workpiece 11 and the thickness of the annular frame 19 is provided on the outer periphery of the support table.

When the workpiece 11 and the annular frame 19 are placed on the support table so that the back surface 11b of the workpiece 11 and the other surface of the annular frame 19 are in contact with the surface of the support table, the difference in thickness is absorbed by the stepped structure. , the surface 11a of the workpiece 11 and one surface of the annular frame 19 are flush with each other.

A tape body (not shown) is provided above the support table. A roller-shaped pressing member (not shown) is arranged near the tape body to press the dicing tape 17 fed from the tape body against the workpiece 11 . The pressing member is configured to be movable in a predetermined direction while rotating.

Further, a cutter (not shown) for circularly cutting the dicing tape 17 attached to the workpiece 11 and the annular frame 19 is provided near the tape body. The cutter cuts the dicing tape 17 into a circular shape so that the dicing tape 17 has a predetermined diameter larger than the inner diameter of the opening of the annular frame 19 and smaller than the outer diameter of the annular frame 19 .

In the attaching step (S10), first, the workpiece 11 and the annular frame 19 are placed on the support table so that the surface 11a of the workpiece 11 and one side of the annular frame 19 face upward.

Then, the dicing tape 17 is placed between the pressing member and the surface 11a of the workpiece 11, and the pressing member is rotated and moved along the X-axis direction while pressing the surface 11a side with the pressing member.

Thereafter, using a cutter, the dicing tape 17 is cut into a circular shape so that the dicing tape 17 has the above-described predetermined diameter. Thereby, the workpiece unit 21 in which the workpiece 11 and the annular frame 19 are integrated via the dicing tape 17 is formed.

After the affixing step (S10), a shield tunnel is formed in the workpiece 11 using the laser processing device 2 (shield tunnel forming step ( S20 )). FIG. 3A is a partial cross-sectional side view of the workpiece 11 and the like when the machining head 12a and the chuck table 10 are moved relative to each other, and FIG. 10 is a partial cross-sectional side view of the workpiece 11 and the like after relatively moving the workpiece 10. FIG.

In the shield tunnel forming step ( S20 ), first, the workpiece unit 21 is placed on the holding surface 10a with the surface 11a of the workpiece 11 facing downward . In this state, the suction source is operated to apply negative pressure to the holding surface 10a. Furthermore, the annular frame 19 is fixed with a clamp unit. As a result, the surface 11 a side of the workpiece 11 is held by the chuck table 10 via the dicing tape 17 .

Next, the direction of the chuck table 10 is adjusted so that the dividing line 13 of the workpiece 11 is parallel to the X-axis direction. Then, the position of the chuck table 10 is adjusted so that the lower end of the processing head 12a is located on one end side of one planned division line 13 in the X-axis direction (for example, the end side in the +X direction) (see FIG. 3A )reference).

After that, the rear surface 11b of the workpiece 11 is irradiated with a pulsed laser beam L having a wavelength that is transparent to the workpiece 11 from the processing head 12a. At this time, the focused area of the laser beam L is positioned inside the workpiece 11 .

The X-axis movement unit 26 is operated to move the chuck table 10 in the X-axis direction in a state in which the focused area of the laser beam L irradiated from the back surface 11b side of the workpiece 11 is positioned inside the workpiece 11. move to

As a result, the laser beam L is irradiated along the dividing line 13 while the processing head 12a is moved relative to the chuck table 10. As shown in FIG. In this specification, the relative movement speed between the machining head 12a and the chuck table 10 in the X-axis direction is called machining speed.

For example, the workpiece 11 is processed by setting the processing conditions as follows.
Wavelength of laser beam L: 1064 nm
Pulse energy: 50 μJ
Pulse repetition frequency: 1 kHz
Machining speed in the X-axis direction: 20mm/s
Number of passes: 1

The pulse energy means energy per pulse. Further, the number of passes means the number of times the laser beam L is irradiated along one dividing line 13 with the condensing area positioned inside the workpiece 11 .

After moving the chuck table 10 in the X-axis direction so as to irradiate the laser beam L from one end in the X-axis direction to the other end (for example, the end in the -X direction) of one planned division line 13, the laser beam The irradiation of L is temporarily stopped (see FIG. 3(B)).

Next, the chuck table 10 is indexed and fed in the Y-axis direction by a predetermined index amount, and the lower end of the machining head 12a is placed on another scheduled division line 13 adjacent in the Y-axis direction to the one scheduled division line 13 machined immediately before. positioned in

Next, the chuck table 10 is irradiated with the laser beam L from the other end (for example, the end in the -X direction) to one end (for example, the end in the +X direction) of the other scheduled division line 13 in the X-axis direction. is moved in the X-axis direction, the irradiation of the laser beam L is once again stopped (see FIG. 3B).

In this way, the laser beam L is irradiated along all the dividing lines 13 parallel to one direction. After that, the chuck table 10 is rotated by 90 degrees, and the laser beam L is irradiated along all the dividing lines 13 parallel to the other direction perpendicular to the one direction. Thereby, a plurality of shield tunnels 11 d are formed along each of all the planned division lines 13 .

If the machining speed in the X-axis direction exceeds 50 mm/s, it becomes difficult to form shield tunnels along the dividing line 13 . Various causes are conceivable, but for example, the shield tunnel may be formed in a meandering manner with respect to the line to be divided 13 . Therefore, it is more preferable to set the processing speed in the XY plane direction to 50 mm/s or less.

FIG. 4A is a perspective view showing the structure of one shield tunnel 11d. In addition, in FIG. 4A, part of the thickness direction of the workpiece 11 (for example, the direction from the front surface 11a to the back surface 11b) is omitted. Each shield tunnel 11 d has a pore 11 e formed along the thickness direction of the workpiece 11 . The pore 11e is a substantially columnar elongated space with a diameter of about 1 μm.

The shield tunnel 11d further has an altered region 11f formed to surround the side surface of the hole 11e. The denatured region 11f is, for example, a substantially cylindrical region having a diameter of approximately 5 μm to approximately 20 μm. is formed.

The denatured region 11f is a region in which a part of the workpiece 11 receives energy from the laser beam L and has changed in structure, density, etc. compared to a part not irradiated with the laser beam L. For example, when the workpiece 11 is made of a single crystal material such as silicon, the altered region 11f becomes an amorphous region or a polycrystalline region.

FIG. 4B is a cross-sectional view of part of the workpiece 11 showing a plurality of shield tunnels 11d formed along one dividing line 13. FIG. In FIG. 4B, the sides of the altered regions 11f of the two shield tunnels 11d adjacent to each other along the dividing line 13 are connected, but the sides of the two altered regions 11f are connected along the dividing line 13. In FIG. can be separated from each other. In addition, in FIG. 4B, a part of the workpiece 11 in the thickness direction is omitted.

After the shield tunnel forming step (S20), ultrasonic waves are applied to the workpiece 11 through the liquid 40 such as water (for example, pure water) using the ultrasonic wave applying device 38, and the dicing tape 17 is expanded. , the shield tunnel 11d is destroyed and the workpiece 11 is divided (dividing step (S30)). FIG. 5A is a partial cross-sectional side view of the ultrasonic applying device 38 and the like.

The ultrasound applicator 38 has a container 42 . The container 42 is filled with the liquid 40 up to a predetermined height. Inside the container 42 , a plurality of legs 44 that can extend and contract in the height direction of the container 42 are arranged, and the bottoms of the legs 44 are fixed to the inner bottom of the container 42 . It should be noted that FIG. 5A shows the legs 44 in a fully extended state.

A ring-shaped support portion 44 a is fixed to the upper end of each leg portion 44 . The annular frame 19 of the workpiece unit 21 is placed on the upper surface of the support portion 44a. A plurality of clamp units 46 are provided on the outer peripheral side surface of the support portion 44a.

Each clamp unit 46 is discretely arranged at different positions in the circumferential direction of the support portion 44a. For example, when the support portion 44a is viewed from above, the four clamp units 46 are provided at 0 o'clock, 3 o'clock, 6 o'clock and 9 o'clock.

A push-up device 48 for pushing up the dicing tape 17 of the workpiece unit 21 from below is provided inside the plurality of leg portions 44 . The push-up device 48 has a plurality of legs 48 a that can extend and contract in the height direction of the container 42 , and the bottoms of the legs 48 a are fixed to the inner bottom of the container 42 . 5A shows the legs 48a positioned at the same height as the legs 44. As shown in FIG.

A ring-shaped push-up member 48b is provided at the upper end of each leg portion 48a. A portion of the base material layer of the dicing tape 17 located between the outer peripheral edge of the workpiece 11 and the inner diameter of the annular frame 19 contacts the upper surface of the push-up member 48b.

An ultrasonic wave generating unit 50 is fixed to the inner bottom of the container 42 . The ultrasonic wave generating unit 50 has a piezoelectric element (not shown) formed using a piezoelectric material such as lead zirconate titanate (PZT).

A piezoelectric element vibrates by applying a predetermined AC voltage to the piezoelectric element. Thereby, the ultrasonic wave generating unit 50 generates ultrasonic waves having a predetermined frequency exceeding 20 kHz (for example, a frequency of 20 kHz to 100 kHz).

In the dividing step (S30), first, as shown in FIG. 5A, the workpiece unit 21 is placed on the support portion 44a. Then, the upper portion of the annular frame 19 is pressed by each clamp unit 46 . Thereby, the workpiece unit 21 is fixed by the clamp unit 46 and the support portion 44a.

After that, the legs 44 and 48a are contracted to the same predetermined length so that the workpiece 11 is positioned at a position lower than the water level of the liquid 40 and higher than the ultrasonic wave generating unit 50 . As a result, the entire workpiece unit 21 is immersed in the liquid 40 . By keeping the leg portion 44 at a predetermined length, the distance between the front surface 11a (or the rear surface 11b) and the ultrasonic wave generating unit 50 can be made constant.

In addition, the height position of the workpiece 11 may be adjusted to a predetermined position where ultrasonic waves are easily transmitted. For example, when the wavelength of the standing wave of the ultrasonic waves generated in the liquid 40 is λ, the position {(2n−1)λ}/4 from the upper end of the ultrasonic wave generation unit 50 (where n is 1 or more) natural number), the workpiece 11 may be positioned.

After positioning the workpiece 11 at an appropriate height position, a predetermined AC voltage is applied to the ultrasonic wave generating unit 50 to generate ultrasonic waves. Ultrasonic waves propagate in the liquid 40 in the form of compressional waves (that is, longitudinal waves). FIG. 5B is a diagram showing how ultrasonic waves are applied to the workpiece 11 through the liquid 40 .

Next, the dicing tape 17 is expanded. FIG. 5C is a diagram showing how the dicing tape 17 is expanded while applying ultrasonic waves to the workpiece 11 through the liquid 40 . While maintaining the length of the leg portion 44, the thrust-up member 48b of the thrust-up device 48 is positioned at a predetermined position higher than the support portion 44a.

The upper end of the leg portion 48a is gradually raised to the predetermined position over a predetermined period of time (for example, several seconds to several tens of seconds), but may be instantaneously raised to the predetermined position. By raising the upper ends of the leg portions 48a to a predetermined position, the dicing tape 17 is radially expanded (that is, expanded). Thereby, the workpiece 11 receives tensile stress in the radial direction.

The radial tensile stress that the workpiece 11 receives is proportional to, for example, the amount of rise of the upper end of the leg portion 48 a relative to the leg portion 44 . In the present embodiment, since ultrasonic waves are applied through the liquid 40, the upper ends of the legs 48a when the workpiece 11 is divided by applying only tensile stress without applying ultrasonic waves through the liquid 40. The work piece 11 can be divided along a plurality of dividing lines 13 even if the amount of elevation of the leg portion 48a is reduced compared to the amount of elevation of .

In other words, the work piece 11 can be divided even if the tensile stress applied to the work piece 11 is reduced. , the possibility of defective processing can be reduced.

By providing the liquid 40 between the workpiece 11 and the ultrasonic wave generating unit 50, compared to the case where only a gas such as air exists between the workpiece 11 and the ultrasonic wave generating unit 50, Acoustic impedance when ultrasonic waves propagate to the workpiece 11 can be reduced. That is, the liquid 40 functions as an acoustic matching layer that improves the propagation efficiency of ultrasonic waves compared to air.

In addition, since the liquid 40 enters the pores 11e, the ultrasonic waves can also propagate within the pores 11e. Therefore, it is more efficient than applying ultrasonic waves to the workpiece 11 in a state where the liquid 40 does not exist in the pores 11e (for example, a state in which the workpiece 11 is exposed to the atmospheric pressure environment). can destroy the denatured region 11f.

In addition, when the upper end of the leg portion 48a is gradually raised to a predetermined position, the liquid 40 also enters into the cracks of the altered region 11f that are being destroyed by the tensile stress, so the ultrasonic wave is also applied to the cracks of the altered region 11f. can propagate. Therefore, it is possible to further reduce the possibility of defective machining compared to the case of momentarily raising to a predetermined position.

In addition, scraps and the like generated when the work piece 11 is divided are dispersed in the liquid 40 by the ultrasonic vibration, and are less likely to adhere to the back surface 11 b of the work piece 11 . Therefore, it is possible to prevent dust and the like from adhering to the surface of the chip 23 .

Furthermore, by using water as the liquid 40 without using chemicals, chemicals, etc., the wastewater treatment is easier than etching treatment. Another advantage is that the container 42, the leg portion 44, the support portion 44a, and the push-up device 48 do not need to be given chemical resistance such as acid resistance.

After the dividing step (S30), a plurality of divided chips 23 are picked up from the workpiece 11 (picking up step (S40)). In the pick-up step (S40), an ultraviolet irradiation device (not shown) is used to irradiate the dicing tape 17 with ultraviolet rays in order to reduce the adhesive strength of the adhesive layer of the dicing tape 17. FIG. Further, a carrier device (not shown) arranged above the ultrasonic wave applying device 38 is used to carry the chip 23 .

The transport device has an arm (not shown) movable in the X-axis (or Y-axis) direction and the Z-axis direction. The upper surface of a disk-shaped head (not shown) is fixed to the lower end of the arm, and a plurality of suction pads (not shown) are provided on the lower surface of the head. Each suction pad is arranged at a position corresponding to the position of the chip 23 .

Each suction pad has a channel (not shown) connected to a suction source (not shown) such as an ejector. One end (that is, opening) of this channel is exposed below the suction pad. A suction force is generated at the opening of the suction pad due to the negative pressure generated by the suction source.

In the pick-up step (S40), the leg 44 and the leg 48a are extended while the push-up member 48b remains at a predetermined position higher than the support 44a (see FIG. 5C).

At this time, the back surface of the dicing tape 17 is positioned above the surface of the liquid 40 . Thereby, the plurality of chips 23 are positioned above the water level of the liquid 40 . Thereafter, an ultraviolet irradiation device is placed in the space between the back side of the dicing tape 17 and the water surface of the liquid 40 to irradiate the dicing tape 17 with ultraviolet rays. This reduces the adhesive strength of the adhesive layer.

Next, the arms of the conveying device are moved in the X-axis direction and positioned directly above the workpiece 11 . After that, the arm is moved in the Z-axis direction to bring the suction pad into contact with the chip 23, and then the suction source is operated to suck the chip 23 with the suction pad.

Next, the arms are moved in the Z-axis direction to separate the chips 23 from the dicing tape 17, and then moved in the X-axis direction to convey each chip 23 to a storage tray (not shown) that stores the chips 23. .

In order to irradiate the ultraviolet rays, it is not necessary to arrange the ultraviolet irradiation device between the bottom of the workpiece unit 21 and the water level of the liquid 40 . For example, after the legs 44 are extended to position the workpiece unit 21 above the level of the liquid 40, the clamp unit 46 is released to move the workpiece unit 21 to another ultraviolet irradiation device (not shown). transport. Then, the dicing tape 17 is irradiated with ultraviolet rays using another ultraviolet irradiation device. After that, each chip 23 is transferred to a storage tray using a transfer device (not shown).

Next, a second embodiment will be described. In the dividing step (S30) of the second embodiment, after applying ultrasonic waves to the workpiece 11 through the liquid 40, the workpiece 11 is removed from the liquid 40, and then the dicing tape 17 is expanded to , divides the workpiece 11 . This point is different from the first embodiment.

In the dividing step (S30) of the second embodiment, first, using the ultrasonic wave applying device 52 having the container 42, the leg portion 44, the support portion 44a, and the ultrasonic wave generating unit 50 which are the same as those of the first embodiment, Ultrasonic waves are applied to the workpiece 11 (ultrasonic wave application step). Note that the container 42 is filled with the liquid 40 to a predetermined depth.

FIG. 7A is a partial cross-sectional side view of the ultrasonic applying device 52 and the like. In the ultrasonic wave application step, first, the workpiece unit 21 is placed on the support portion 44a, and the upper portion of the annular frame 19 is pressed by each clamp unit 46. As shown in FIG.

After that, the legs 44 are contracted so that the workpiece 11 is positioned at a position lower than the water level of the liquid 40 and higher than the ultrasonic wave generating unit 50 , and the entire workpiece unit 21 is immersed in the liquid 40 .

Then, ultrasonic waves are generated by the ultrasonic wave generating unit 50 and applied to the workpiece 11 through the liquid 40 . After applying ultrasonic waves to the workpiece 11 through the liquid 40, the legs 44 are extended to position the workpiece 11 above the level of the liquid 40, and the clamping unit 46 is released.

Next, the workpiece 11 is divided by expanding the dicing tape 17 using the dividing device 60 (expanding step). FIG. 7B is a partial cross-sectional side view of the dividing device 60 and the like.

In splitting device 60 , leg 44 of ultrasound applicator 52 corresponds to leg 54 of ultrasound applicator 38 . Further, the support portion 44a corresponds to the support portion 54a, and the clamp unit 46 corresponds to the clamp unit 56. As shown in FIG. Furthermore, a thrusting device 58 corresponds to the thrusting device 48 .

In the expanding process, the workpiece 11 is moved from the ultrasonic wave application device 52 to the support portion 44 a of the dividing device 60 , and then the annular frame 19 is held down by the clamp units 46 . Then, while the height position of the leg portion 58a of the push-up device 58 is fixed, the leg portion 54 is gradually retracted.

As a result, the push-up member 58b is positioned at a predetermined position higher than the support portion 54a, the dicing tape 17 is expanded in the radial direction, and the workpiece 11 receives a tensile stress in the radial direction. FIG. 7C is a diagram showing how the dicing tape 17 is expanded using the dividing device 60. As shown in FIG.

In the second embodiment as well, the denatured region 11f has a lower mechanical strength than before the ultrasonic wave is applied, so the workpiece 11 can be divided even if the tensile stress is reduced. Therefore, compared to the case where the workpiece 11 is divided by applying only the tensile stress to the workpiece 11, the possibility of defective machining can be reduced.

After the expanding process, a pick-up step (S40) is performed. In the pick-up step (S40), the ultraviolet irradiation device (not shown) is placed on the back side of the dicing tape 17 to irradiate the dicing tape 17 with ultraviolet rays. This reduces the adhesive strength of the adhesive layer. After that, each chip 23 is transferred to a storage tray (not shown) using the above-described transfer device (not shown).

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

2 laser processing device 4 base 6 base 8 wall 10 chuck table 10a holding surface 11 workpiece 11a front surface 11b rear surface 11c notch 11d shield tunnel 11e pore 11f alteration region 12 laser beam irradiation unit 12a processing head 12b imaging unit 13 division Scheduled Line 15 Device 15a Device Area 15b Surplus Periphery Area 16 Y-Axis Movement Unit 17 Dicing Tape 18 Y-Axis Guide Rail 19 Annular Frame 20 Y-Axis Movement Table 21 Workpiece Unit 22 Y-Axis Ball Screw 23 Chip 24 Y-Axis Pulse Motor 26 X Axis movement unit 28 X-axis guide rail 30 X-axis movement table 32 X-axis ball screw 34 X-axis pulse motor 36 Support base 38 Ultrasonic wave application device 40 Liquid 42 Container 44 Leg 44a Support 46 Clamp unit 48 Push-up device 48a Leg 48b push-up member 50 ultrasonic wave generating unit 52 ultrasonic wave applicator 54 leg 54a support 56 clamp unit 58 push-up device 58a leg 58b push-up member 60 dividing device L laser beam

Claims (3)

A method for manufacturing a plurality of chips by dividing a workpiece having a plurality of regions on the surface side thereof partitioned by a plurality of intersecting dividing lines along the dividing lines, the method comprising:
By attaching an extensible tape to the work piece and the annular frame , the work piece is placed in the opening of the ring frame, and the work piece is attached to the annular frame through the tape. an affixing step forming a workpiece unit integrated with the frame ;
The pulsed laser beam having a wavelength that is transmissive to the work piece is directed to each split line from the back side of the work piece so that the condensing area of the laser beam is positioned inside the work piece. A shield tunnel forming step of forming a plurality of shield tunnels each having a pore and an altered region surrounding the pore along each planned division line by irradiating along the
After the shield tunnel forming step, the annular frame is fixed on a plurality of legs provided in the container, and the height position of the workpiece unit is adjusted by expanding and contracting the plurality of legs. applying ultrasonic waves to the workpiece through the liquid while the workpiece unit is positioned at a position lower than the water level of the liquid filled to a predetermined height from the bottom of the container; a dividing step of dividing the workpiece along the plurality of planned dividing lines by expanding the tape with a thrusting device that thrusts the tape from below ;
A method of manufacturing a plurality of chips, comprising: The dividing step divides the workpiece along the plurality of planned dividing lines by expanding the tape while applying ultrasonic waves to the workpiece through a liquid. Item 2. A method of manufacturing a plurality of chips according to Item 1. The application of the ultrasonic waves in the dividing step is performed by adjusting the height position of the workpiece unit with the plurality of legs so as to achieve a predetermined height position where ultrasonic waves are easily transmitted in the liquid. 3. The method of claim 1 or 2 , comprising adjusting the height position of the workpiece .

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