JP6973916B2 - How to make chips - Google Patents

Description

The present invention relates to a method for manufacturing a chip in which a plate-shaped workpiece is divided to manufacture a plurality of chips.

In order to divide a plate-shaped workpiece (work) represented by a wafer into multiple chips, a transmissive laser beam is focused inside the workpiece and modified by multiphoton absorption. A method for forming a modified layer (modified region) is known (see, for example, Patent Document 1). Since the modified layer is more brittle than other regions, the modified layer is formed along the planned division line (street) and then a force is applied to the workpiece to be processed from this modified layer as a starting point. You can divide an object into multiple chips.

When applying force to the work piece on which the modified layer is formed, for example, a method of attaching an expandable sheet (expand tape) to the work piece to expand it is adopted (for example, Patent Document 2). reference). In this method, usually, before irradiating a laser beam to form a modified layer on a work piece, an expand sheet is attached to the work piece, and then the modified layer is formed and then the expanded sheet is expanded. Divide the workpiece into multiple chips.

Japanese Unexamined Patent Publication No. 2002-192370 Japanese Unexamined Patent Publication No. 2010-206136

However, in the method of expanding the expanded sheet as described above, since the expanded sheet after use cannot be used again, the cost required for manufacturing the chip tends to be high. In particular, a high-performance expanded sheet in which the adhesive material does not easily remain on the chip is expensive, so that the cost required for manufacturing the chip is also high when such an expanded sheet is used.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a method for manufacturing a chip capable of dividing a plate-shaped workpiece and manufacturing a plurality of chips without using an expand sheet. It is to be.

According to one aspect of the present invention, a plurality of ferroelectric substrates having a chip region divided into a plurality of regions to be chips by a plurality of intersecting scheduled division lines and an outer peripheral surplus region surrounding the chip region. A method for manufacturing a chip for manufacturing the chip, in which a holding step of directly holding the ferroelectric substrate on a holding table and a wavelength having a transparency to the ferroelectric substrate after the holding step is performed. The laser beam is irradiated only to the chip region of the ferroelectric substrate along the planned division line so that the focusing point of the laser beam is positioned inside the ferroelectric substrate held on the holding table, and the chip is used. A laser processing step of forming a modified layer along the planned division line of the region and using the outer peripheral surplus region as a reinforcing portion on which the modified layer is not formed, and holding the modified layer after performing the laser processing step. It is provided with a carry-out step of carrying out the ferroelectric substrate from the table, and a division step of applying a force to the ferroelectric substrate to divide the ferroelectric substrate into individual chips after performing the carry-out step. , the division step, a plurality of portions of the ferroelectric substrate is divided by several of the dividing line and held in each of the plurality of holding portions, relative movement away from each other with respect to the holding portion of the plurality of Provided is a method for manufacturing a chip, which divides a ferroelectric substrate into individual chips by applying a force to cause the ferroelectric substrate to be divided at once along a plurality of planned division lines.

In one aspect of the present invention, a reinforcing portion removing step for removing the reinforcing portion may be further provided after performing the laser machining step and before performing the dividing step. Further, in one aspect of the present invention, the upper surface of the holding table is made of a flexible material, and in the holding step, the surface side of the ferroelectric substrate may be held by the flexible material.

In the method for manufacturing a chip according to one aspect of the present invention, while the ferroelectric substrate is directly held by a holding table, only the chip region of the ferroelectric substrate is irradiated with a laser beam to modify it along a planned division line. A layer is formed, and then a plurality of parts of the ferroelectric substrate divided by a planned division line are held by a plurality of holding portions, and a force is applied to the plurality of holding portions so as to move relative to each other in a direction away from each other. Then, the ferroelectric substrate is divided into individual chips by a method of dividing the ferroelectric substrate along a plurality of planned division lines. Therefore, a force is applied to the ferroelectric substrate to divide the ferroelectric substrate into individual chips. Therefore, it is not necessary to use an expand sheet. As described above, according to the chip manufacturing method according to one aspect of the present invention, a plurality of chips can be manufactured by dividing a ferroelectric substrate, which is a plate-shaped workpiece, without using an expand sheet.

Further, in the chip manufacturing method according to one aspect of the present invention, a laser beam is irradiated only to the chip region of the ferroelectric substrate to form a modified layer along the planned division line, and the outer peripheral surplus region is formed as a modified layer. Since the reinforcing portion is not formed, the chip region is reinforced by this reinforcing portion. Therefore, the ferroelectric substrate is not divided into individual chips due to the force applied during transportation or the like, and the ferroelectric substrate cannot be appropriately transported.

It is a perspective view which shows the structural example of the workpiece schematically. It is a perspective view which shows the structural example of a laser processing apparatus schematically. FIG. 3A is a cross-sectional view for explaining the holding step, and FIG. 3B is a cross-sectional view for explaining the laser machining step. FIG. 4A is a plan view schematically showing the state of the workpiece after the laser machining step, and FIG. 4B schematically shows the state of the workpiece after the laser machining step. It is sectional drawing which shows. 5 (A) and 5 (B) are cross-sectional views for explaining the reinforcing portion removing step. It is a perspective view which shows the structural example of the division apparatus and the like schematically. FIG. 7A is a cross-sectional view schematically showing a part of the dividing device, and FIG. 7B is an enlarged cross-sectional view showing a part of FIG. 7A. It is a perspective view for demonstrating how the workpiece is adsorbed and held in a division step. FIG. 9 (A) is a cross-sectional view for explaining how the workpiece is adsorbed and held in the division step, and FIG. 9 (B) explains how the workpiece is divided in the division step. It is a cross-sectional view for this. It is sectional drawing for demonstrating the holding step which concerns on a modification. FIG. 11A is a cross-sectional view for explaining the division step according to the modification, and FIG. 11B shows the state of the workpiece before dividing the chip region in the division step according to the modification. It is a top view schematically showing.

An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. The chip manufacturing method according to this embodiment includes a holding step (see FIG. 3 (A)), a laser machining step (see FIGS. 3 (B), 4 (A) and 4 (B)), an unloading step, and reinforcement. Part removal step (see FIGS. 5 (A) and 5 (B)) and division step (FIG. 6, FIG. 7 (A), FIG. 7 (B), FIG. 8, FIG. 9 (A) and FIG. 9 (B). ) Includes).

In the holding step, the workpiece (work) having the chip region divided into a plurality of regions by the scheduled division line and the outer peripheral surplus region surrounding the chip region is directly held by the chuck table (holding table). In the laser machining step, the workpiece is irradiated with a laser beam having a wavelength having transparency to form a modified layer (modified region) along the planned division line in the chip region, and the outer peripheral surplus region is modified. It is a reinforcing part where no layer is formed.

In the carry-out step, the work piece is carried out from the holding table. In the reinforcing portion removing step, the reinforcing portion is removed from the workpiece. In the division step, a plurality of parts of the workpiece to be divided by the planned division line are held by a plurality of holding portions, and a force is applied to the plurality of holding portions to move them relatively away from each other. This work piece is divided into a plurality of chips by a method of dividing an object along a plurality of scheduled division lines. Hereinafter, the method for manufacturing a chip according to this embodiment will be described in detail.

FIG. 1 is a perspective view schematically showing a configuration example of a workpiece (work) 11 used in the present embodiment. As shown in FIG. 1, the workpiece 11 is, for example, a semiconductor such as silicon (Si), gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), silicon carbide (SiC), or sapphire. Dielectrics (insulators) such as (Al ₂ O ₃ ), soda glass, borosilicate glass, and quartz glass, or strong dielectrics (strong dielectric) such as _{lithium tantalate (LiTa 3} ) and lithium niobate (LiNb _3). It is a disk-shaped wafer (substrate) made of (body crystal).

The surface 11a side of the workpiece 11 is divided into a plurality of regions 15 serving as chips by a plurality of intersecting scheduled division lines (streets) 13. In the following, a substantially circular region including all of the plurality of regions 15 to be chips is referred to as a chip region 11c, and an annular region surrounding the chip region 11c is referred to as an outer peripheral surplus region 11d.

Each region 15 in the chip region 11c includes an IC (Integrated Circuit), a MEMS (Micro Electro Mechanical Systems), an LED (Light Emitting Diode), an LD (Laser Diode), a photodiode (Photodiode), and a SAW, as required. Devices such as (Surface Acoustic Wave) filters and BAW (Bulk Acoustic Wave) filters are formed.

By dividing the workpiece 11 along the scheduled division line 13, a plurality of chips can be obtained. Specifically, when the workpiece 11 is a silicon wafer, a chip that functions as a memory, a sensor, or the like can be obtained, for example. When the workpiece 11 is a gallium arsenide substrate, an indium phosphide substrate, or a gallium nitride substrate, a chip that functions as a light emitting element, a light receiving element, or the like can be obtained, for example.

When the workpiece 11 is a silicon carbide substrate, for example, a chip that functions as a power device or the like can be obtained. When the workpiece 11 is a sapphire substrate, for example, a chip that functions as a light emitting element or the like can be obtained. When the workpiece 11 is a glass substrate made of soda glass, borosilicate glass, quartz glass, or the like, for example, a chip that functions as an optical component or a cover member (cover glass) can be obtained.

When the workpiece 11 is a ferroelectric substrate (ferroelectric crystal substrate) made of a ferroelectric substance such as lithium tantalate or lithium niobate, a chip that functions as a filter, an actuator, or the like can be obtained, for example. There are no restrictions on the material, shape, structure, size, thickness, etc. of the workpiece 11. Similarly, there are no restrictions on the type, quantity, shape, structure, size, arrangement, etc. of the device formed in the region 15 to be the chip. The device may not be formed in the region 15 to be a chip.

In the chip manufacturing method according to the present embodiment, a disk-shaped ferroelectric substrate is used as the workpiece 11 to manufacture a plurality of chips. Specifically, first, a holding step of directly holding the workpiece 11 on the chuck table is performed. FIG. 2 is a perspective view schematically showing a configuration example of the laser processing apparatus used in the present embodiment.

As shown in FIG. 2, the laser processing apparatus 2 includes a base 4 on which each component is mounted. On the upper surface of the base 4, a horizontal movement mechanism for moving a chuck table (holding table) 6 for sucking and holding the workpiece 11 in the X-axis direction (machining feed direction) and the Y-axis direction (indexing feed direction). 8 is provided. The horizontal movement mechanism 8 includes a pair of X-axis guide rails 10 fixed to the upper surface of the base 4 and substantially parallel to the X-axis direction.

An X-axis moving table 12 is slidably attached to the X-axis guide rail 10. A nut portion (not shown) is provided on the back surface side (lower surface side) of the X-axis moving table 12, and an X-axis ball screw 14 substantially parallel to the X-axis guide rail 10 is screwed into this nut portion. ing.

An X-axis pulse motor 16 is connected to one end of the X-axis ball screw 14. By rotating the X-axis ball screw 14 with the X-axis pulse motor 16, the X-axis moving table 12 moves in the X-axis direction along the X-axis guide rail 10. An X-axis scale 18 for detecting the position of the X-axis moving table 12 in the X-axis direction is installed at a position adjacent to the X-axis guide rail 10.

A pair of Y-axis guide rails 20 substantially parallel to the Y-axis direction are fixed to the surface (upper surface) of the X-axis moving table 12. A Y-axis moving table 22 is slidably attached to the Y-axis guide rail 20. A nut portion (not shown) is provided on the back surface side (lower surface side) of the Y-axis moving table 22, and a Y-axis ball screw 24 substantially parallel to the Y-axis guide rail 20 is screwed into this nut portion. ing.

A Y-axis pulse motor 26 is connected to one end of the Y-axis ball screw 24. By rotating the Y-axis ball screw 24 with the Y-axis pulse motor 26, the Y-axis moving table 22 moves in the Y-axis direction along the Y-axis guide rail 20. At a position adjacent to the Y-axis guide rail 20, a Y-axis scale 28 for detecting the position of the Y-axis moving table 22 in the Y-axis direction is installed.

A support base 30 is provided on the front surface side (upper surface side) of the Y-axis moving table 22, and a chuck table 6 is arranged on the upper portion of the support base 30. The front surface (upper surface) of the chuck table 6 is a holding surface 6a that sucks and holds the back surface 11b side (or the surface 11a side) of the work piece 11 described above. The holding surface 6a is made of a porous material having high hardness such as aluminum oxide. However, the holding surface 6a may be made of a flexible material typified by a resin such as polyethylene or epoxy.

The holding surface 6a is provided with a suction source 34 (see FIG. 3 (A), etc.) via a suction path 6b (see FIG. 3 (A), etc.) and a valve 32 (see FIG. 3 (A), etc.) formed inside the chuck table 6. It is connected to A) etc.). A rotation drive source (not shown) is provided below the chuck table 6, and the rotation drive source rotates the chuck table 6 around a rotation axis substantially parallel to the Z-axis direction.

A columnar support structure 36 is provided behind the horizontal movement mechanism 8. A support arm 38 extending in the Y-axis direction is fixed to the upper part of the support structure 36, and a wavelength having transparency to the workpiece 11 (wavelength that is difficult to be absorbed) is fixed to the tip of the support arm 38. A laser irradiation unit 40 is provided that pulsates the laser beam 17 (see FIG. 3B) of the above and irradiates the workpiece 11 on the chuck table 6.

A camera 42 that captures an image on the front surface 11a side or the back surface 11b side of the workpiece 11 is provided at a position adjacent to the laser irradiation unit 40. The image formed by imaging the workpiece 11 or the like with the camera 42 is used, for example, when adjusting the positions of the workpiece 11 and the laser irradiation unit 40.

Components such as the chuck table 6, the horizontal movement mechanism 8, the laser irradiation unit 40, and the camera 42 are connected to a control unit (not shown). The control unit controls each component so that the workpiece 11 is appropriately machined.

FIG. 3A is a cross-sectional view for explaining the holding step. In addition, in FIG. 3A, some components are shown by functional blocks. In the holding step, as shown in FIG. 3A, for example, the back surface 11b of the workpiece 11 is brought into contact with the holding surface 6a of the chuck table 6. Then, the valve 32 is opened to apply the negative pressure of the suction source 34 to the holding surface 6a.

As a result, the workpiece 11 is sucked and held by the holding table 6 with the surface 11a side exposed upward. In this embodiment, as shown in FIG. 3A, the back surface 11b side of the workpiece 11 is directly held by the chuck table 6. That is, in the present embodiment, it is not necessary to attach the expand sheet to the workpiece 11.

After the holding step, a laser processing step is performed in which the workpiece 11 is irradiated with a laser beam 17 having a wavelength having a transmittance to form a modified layer along the scheduled division line 13. FIG. 3B is a cross-sectional view for explaining the laser machining step, and FIG. 4A is a plan view schematically showing the state of the workpiece 11 after the laser machining step. 4 (B) is a cross-sectional view schematically showing a state of the workpiece 11 after the laser machining step. In addition, in FIG. 3B, some components are shown by functional blocks.

In the laser machining step, first, the chuck table 6 is rotated so that, for example, the extending direction of the target division scheduled line 13 is parallel to the X-axis direction. Next, the chuck table 6 is moved to align the position of the laser irradiation unit 40 on the extension line of the target division scheduled line 13. Then, as shown in FIG. 3B, the chuck table 6 is moved in the X-axis direction (that is, the direction in which the target division scheduled line 13 extends).

After that, when the laser irradiation unit 40 reaches directly above one of the boundaries between the chip region 11c and the outer peripheral surplus region 11d existing at two locations on the target division scheduled line 13, the laser beam from the laser irradiation unit 40 Irradiation of 17 is started. In the present embodiment, as shown in FIG. 3B, the laser beam 17 is irradiated from the laser irradiation unit 40 arranged above the workpiece 11 toward the surface 11a of the workpiece 11.

The irradiation of the laser beam 17 is continued until the laser irradiation unit 40 reaches directly above the other boundary between the chip region 11c and the outer peripheral surplus region 11d existing at two locations on the target division scheduled line 13. That is, here, the laser beam 17 is irradiated only in the chip region 11c along the target division scheduled line 13.

Further, the laser beam 17 is irradiated so as to position the condensing point at a position at a predetermined depth from the front surface 11a (or the back surface 11b) inside the workpiece 11. In this way, by condensing the laser beam 17 having a wavelength that is transparent to the workpiece 11 inside the workpiece 11, a part of the workpiece 11 is focused on the condensing point and its vicinity. It can be modified by multiphoton absorption to form a modified layer (modified region) 19 which is a starting point of division. In the present embodiment, since the laser beam 17 is irradiated only in the chip region 11c along the target division scheduled line 13, the modified layer 19 is formed only in the chip region 11c along the target division schedule line 13. NS.

After forming the modified layer 19 at a predetermined depth along the target split line 13, the modified layer 19 is formed at a different depth along the target split line 13 by the same procedure. Form 19. Specifically, for example, as shown in FIG. 4B, the modified layer 19 (first modified layer 19a) is located at three positions where the depths of the workpiece 11 from the front surface 11a (or the back surface 11b) are different. , Second modified layer 19b, third modified layer 19c).

However, there is no particular limitation on the number and positions of the reformed layers 19 formed along one scheduled division line 13. For example, the number of modified layers 19 formed along one scheduled division line 13 may be one. Further, it is desirable that the modified layer 19 is formed under the condition that the crack reaches the front surface 11a (or the back surface 11b). Of course, the modified layer 19 may be formed under the condition that cracks reach both the front surface 11a and the back surface 11b. This makes it possible to divide the workpiece 11 more appropriately.

When the workpiece 11 is a silicon wafer, for example, the modified layer 19 is formed under the following conditions.
Work piece: Silicon wafer Laser beam wavelength: 1340 nm
Laser beam repetition frequency: 90 kHz
Laser beam output: 0.1W to 2W
Chuck table movement speed (machining feed speed): 180 mm / s to 1000 mm / s, typically 500 mm / s

When the workpiece 11 is a gallium arsenide substrate or an indium phosphide substrate, for example, the modified layer 19 is formed under the following conditions.
Workpiece: Gallium arsenide substrate, Indium phosphide substrate Laser beam wavelength: 1064 nm
Laser beam repetition frequency: 20 kHz
Laser beam output: 0.1W to 2W
Chuck table movement speed (machining feed speed): 100 mm / s to 400 mm / s, typically 200 mm / s

When the workpiece 11 is a sapphire substrate, the modified layer 19 is formed under the following conditions, for example.
Work piece: Sapphire substrate Laser beam wavelength: 1045 nm
Laser beam repetition frequency: 100 kHz
Laser beam output: 0.1W to 2W
Chuck table movement speed (machining feed speed): 400 mm / s to 800 mm / s, typically 500 mm / s

When the workpiece 11 is a ferroelectric substrate made of a ferroelectric substance such as lithium tantalate or lithium niobate, the modified layer 19 is formed under the following conditions, for example.
Workpiece: Lithium tantalate substrate, Lithium niobate substrate Laser beam wavelength: 532 nm
Laser beam repetition frequency: 15 kHz
Laser beam output: 0.02W to 0.2W
Chuck table moving speed (machining feed rate): 270 mm / s to 420 mm / s, typically 300 mm / s

When the workpiece 11 is a glass substrate made of soda glass, borosilicate glass, quartz glass, or the like, the modified layer 19 is formed under the following conditions, for example.
Workpiece: Soda glass substrate, borosilicate glass substrate, quartz glass substrate Laser beam wavelength: 532 nm
Laser beam repetition frequency: 50 kHz
Laser beam output: 0.1W to 2W
Chuck table movement speed (machining feed speed): 300 mm / s to 600 mm / s, typically 400 mm / s

When the workpiece 11 is a gallium nitride substrate, for example, the modified layer 19 is formed under the following conditions.
Workpiece: Gallium Nitride Substrate Laser Beam Wavelength: 532nm
Laser beam repetition frequency: 25 kHz
Laser beam output: 0.02W to 0.2W
Chuck table movement speed (machining feed speed): 90 mm / s to 600 mm / s, typically 150 mm / s

When the workpiece 11 is a silicon carbide substrate, for example, the modified layer 19 is formed under the following conditions.
Work piece: Silicon carbide substrate Laser beam wavelength: 532 nm
Laser beam repetition frequency: 25 kHz
Laser beam output: 0.02W to 0.2W, typically 0.1W
Chuck table movement speed (machining feed rate): 90 mm / s to 600 mm / s, typically 90 mm / s in the cleavage direction of the silicon carbide substrate, 400 mm / s in the non-cleavage direction.

After forming the required number of modified layers 19 along the target planned division line 13, the above operation is repeated to form the modified layer 19 along all the other planned division lines 13. As shown in FIG. 4A, the laser machining step is completed when the modified layer 19 is formed along all the scheduled division lines 13.

In the present embodiment, the modified layer 19 is formed only in the chip region 11c along the planned division line 13, and the modified layer 19 is not formed in the outer peripheral surplus region 11d. The strength of 11 is maintained. As a result, the workpiece 11 is not divided into individual chips due to the force applied during transportation or the like. As described above, the outer peripheral surplus region 11d after the laser machining step functions as a reinforcing portion for reinforcing the chip region 11c on which the modified layer 19 is formed.

Further, in the present embodiment, since the modified layer 19 is not formed in the outer peripheral surplus region 11d, for example, cracks extending from the modified layer 19 reach both the front surface 11a and the back surface 11b, and the workpiece 11 is completely formed. Even in the divided situation, each chip does not fall off or disperse. Generally, when the modified layer 19 is formed on the workpiece 11, the workpiece 11 expands in the vicinity of the modified layer 19. In the present embodiment, the expansion force generated by the formation of the modified layer 19 is applied inward in the ring-shaped outer peripheral excess region 11d that functions as a reinforcing portion, thereby pressing each chip and preventing it from falling off or scattering. doing.

After the laser machining step, a unloading step of unloading the workpiece 11 from the chuck table 6 is performed. Specifically, for example, a transfer unit (not shown) capable of sucking and holding the entire front surface 11a (or back surface 11b) of the workpiece 11 sucks the entire surface 11a of the workpiece 11 and then valves. 32 is closed to shut off the negative pressure of the suction source 34, and the workpiece 11 is carried out. In the present embodiment, as described above, since the outer peripheral surplus region 11d functions as a reinforcing portion, the workpiece 11 is divided into individual chips by the force applied during transportation or the like, and the workpiece 11 is divided into individual chips. It does not prevent the 11 from being properly transported.

After the carry-out step, a reinforcing portion removing step for removing the reinforcing portion from the workpiece 11 is performed. 5 (A) and 5 (B) are cross-sectional views for explaining the reinforcing portion removing step. In addition, in FIG. 5A and FIG. 5B, some components are shown by functional blocks. The reinforcing portion removing step is performed using, for example, the cutting device 52 shown in FIGS. 5 (A) and 5 (B).

The cutting device 52 includes a chuck table 54 for sucking and holding the workpiece 11. A part of the upper surface of the chuck table 54 is a holding surface 54a that sucks and holds the chip region 11c of the workpiece 11. The holding surface 54a is connected to the suction source 58 via a suction path 54b formed inside the chuck table 54, a valve 56, and the like.

One end of a suction path 54c for sucking and holding the outer peripheral excess region 11d (that is, the reinforcing portion) of the workpiece 11 is opened in another part of the upper surface of the chuck table 54. The other end of the suction path 54c is connected to the suction source 58 via a valve 60 or the like. The chuck table 54 is connected to a rotation drive source (not shown) such as a motor, and rotates around a rotation axis substantially parallel to the vertical direction.

A cutting unit 62 is arranged above the chuck table 54. The cutting unit 62 includes a spindle 64 that is a rotation axis substantially parallel to the holding surface 54a. An annular cutting blade 66 in which abrasive grains are dispersed in a binder is mounted on one end side of the spindle 64.

A rotary drive source (not shown) such as a motor is connected to the other end side of the spindle 64, and the cutting blade 66 mounted on one end side of the spindle 64 rotates by the force transmitted from the rotary drive source. The cutting unit 62 is supported by, for example, an elevating mechanism (not shown), and the cutting blade 66 is moved in the vertical direction by the elevating mechanism.

It should be noted that on the upper surface of the chuck table 54, a relief groove for a cutting blade (not shown) for preventing contact with the cutting blade 66 is provided at a position corresponding to the boundary between the chip region 11c of the workpiece 11 and the outer peripheral surplus region 11d. ) Is formed.

In the reinforcing portion removing step, first, the back surface 11b of the workpiece 11 is brought into contact with the holding surface 54a of the chuck table 54. Then, the valves 56 and 60 are opened, and the negative pressure of the suction source 58 is applied to the holding surface 54a and the like. As a result, the workpiece 11 is sucked and held by the chuck table 54 with the surface 11a side exposed upward. In this embodiment, as shown in FIG. 5A, the back surface 11b side of the workpiece 11 is directly held by the chuck table 54. That is, again, it is not necessary to attach the expand sheet to the workpiece 11.

Next, the cutting blade 66 is rotated to cut into the boundary between the chip region 11c of the workpiece 11 and the outer peripheral surplus region 11d. At the same time, as shown in FIG. 5A, the chuck table 54 is rotated around a rotation axis substantially parallel to the vertical direction. As a result, the workpiece 11 can be cut along the boundary between the chip region 11c and the outer peripheral surplus region 11d.

After that, the valve 60 is closed to shut off the negative pressure of the suction source 58 with respect to the outer peripheral excess region 11d of the workpiece 11. Then, as shown in FIG. 5B, the outer peripheral surplus region 11d is removed from the chuck table 54. As a result, only the chip region 11c of the workpiece 11 remains on the chuck table 54.

After the reinforcing portion removing step, a division step of dividing the workpiece 11 into individual chips is performed. Specifically, a plurality of portions of the workpiece 11 to be divided by the scheduled division line 13 are each held by a plurality of holding portions, and a force is applied to the plurality of holding portions to move them relatively in a direction away from each other. The workpiece 11 is divided by a method of dividing the workpiece 11 along a plurality of scheduled division lines 13.

FIG. 6 is a perspective view schematically showing a configuration example of a dividing device or the like used in the dividing step of the present embodiment, and FIG. 7A is a cross-sectional view schematically showing a part of the dividing device. Yes, FIG. 7B is an enlarged cross-sectional view showing a part of FIG. 7A. As shown in FIGS. 6, 7 (A) and 7 (B), the dividing device 72 includes a plurality of electrostatic adsorption members (holding portions) 74 arranged at substantially equal intervals. Each electrostatic adsorption member 74 is formed in a rectangular parallelepiped shape (flat plate shape or rod shape) long in a predetermined direction, and the upper surface (adsorption surface) 74a side thereof is the lower surface side (for example, the back surface 11b side) of the workpiece 11. Adsorbs and holds.

The length of the upper surface 74a of the electrostatic adsorption member 74 (the length along the predetermined direction described above) is, for example, larger than the diameter of the workpiece 11 to be divided (in the present embodiment, the chip region 11c). long. On the other hand, the width of the upper surface 74a of the electrostatic adsorption member 74 (the length in the direction perpendicular to the predetermined direction described above) is narrower than the distance between the two adjacent lines to be divided in the workpiece 11. .. Therefore, the portion between the two adjacent lines to be divided (the portion corresponding to the small piece after division) of the workpiece 11 can be adsorbed and held by the electrostatic adsorption member 74.

On the lower surface 74b of each electrostatic adsorption member 74, two strip-shaped elastic sheets (that is, two sheets) extending in a direction perpendicular to the predetermined direction described above (that is, the longitudinal direction of each electrostatic adsorption member 74) (that is, two elastic sheets). The applying mechanism) 76a and 76b are fixed by the adhesive 78 (FIG. 7 (B)). Specifically, one elastic sheet 76a is fixed to one end side in the longitudinal direction of each electrostatic adsorption member 74.

Further, the other elastic sheet 76b is fixed to the other end side in the longitudinal direction of each electrostatic adsorption member 74. Each elastic sheet 76a, 76b is made of a highly elastic material such as rubber and has a predetermined elasticity. The two elastic sheets 76a and 76b connect the electrostatic adsorption members 74 in a state of being arranged in a direction perpendicular to the longitudinal direction thereof.

However, there are no particular restrictions on the material, structure, quantity, arrangement, etc. of the elastic sheets 76a and 76b. For example, a woven fabric or a knitted fabric composed of elastic or non-stretchable fibers may be used as the elastic sheets 76a and 76b. Further, in the present embodiment, a plurality of electrostatic adsorption members 74 are connected by two elastic sheets 76a and 76b, but one (one) or three (three) or more elastic sheets are used. It is also possible to connect a plurality of electrostatic adsorption members 74.

One end side of each of the elastic sheets 76a and 76b is fixed to a cylindrical (cylindrical) roller (giving mechanism) 80a having a rotation axis substantially parallel to the longitudinal direction of the electrostatic adsorption member 74. The roller 80a is connected to a rotation drive source (giving mechanism) 82a such as a motor, and rotates around a rotation axis by a force generated by the rotation drive source 82a.

Similarly, the other end side of each elastic sheet 76a, 76b is fixed to a cylindrical (cylindrical) roller (giving mechanism) 80b having a rotation axis substantially parallel to the longitudinal direction of each electrostatic adsorption member 74. .. The roller 80b is connected to a rotation drive source (giving mechanism) 82b such as a motor, and rotates around a rotation axis by a force generated by the rotation drive source 82b.

By rotating the rollers 80a and 80b with the rotation drive sources 82a and 82b, the elastic sheets 76a and 76b can be wound up by the rollers 80a and 80b, and the elastic sheets 76a and 76b can be unwound from the rollers 80a and 80b to have this elasticity. The tension applied to the sheets 76a and 76b can be adjusted.

In the dividing device 72 of the present embodiment, two sets of rollers 80a and 80b and two sets of rotary drive sources 82a and 82b are used. For example, one set of rollers and one set of rotary drive sources are used. It can also be used to achieve equivalent functionality. In this case, for example, one end side (or the other end side) of each elastic sheet 76a, 76b is fixed, and one set of rollers and one set of rotational drive sources are connected to the other end side (or one end side). It's fine.

As shown in FIGS. 7 (A) and 7 (B), the electrostatic adsorption member 74 includes a columnar (rod-shaped) core material 84a extending in the longitudinal direction thereof and a conductive member 86a that covers the circumference of the core material 84a. I'm out. The conductive member 86a is made of a metal such as copper and functions as one electrode of the electrostatic adsorption member 74. There are no particular restrictions on the material, shape, etc. of the core material 84a, but in this embodiment, a prismatic core material 84a made of silicon is used.

Further, the electrostatic adsorption member 74 includes a columnar (rod-shaped) core material 84b extending in the longitudinal direction thereof, and a conductive member 86b that covers the periphery of the core material 84b. The material, shape, and the like of the core material 84b and the conductive member 86b may be the same as the material, shape, and the like of the core material 84a and the conductive member 86a. The conductive member 86b functions as the other electrode of the electrostatic adsorption member 74.

The core material 84a and the conductive member 86a, and the core material 84b and the conductive member 86b are arranged at predetermined intervals and are covered with the insulating member 88. As a result, a pair of electrodes parallel to each other is realized. The upper surface of the insulating member 88 is the upper surface 74a of the electrostatic adsorption member 74, and the lower surface of the insulating member 88 is the lower surface 74b of the electrostatic adsorption member 74.

As shown in FIG. 6, one electrode (conductive member 86a) of each electrostatic adsorption member 74 is connected to the positive electrode of the DC power supply (power supply unit) 94 via the wiring 90, the switch 92, and the like. Further, the other electrode (conductive member 86b) of each electrostatic adsorption member 74 is connected to the negative electrode of the DC power supply 94 via wiring 90 or the like.

Therefore, by setting the switch 92 to the conduction (ON) state and applying the voltage of the DC power supply 94 to the electrodes of each electrostatic adsorption member 74, an electric field can be generated around each electrostatic adsorption member 74. A transport unit 96 is arranged above the plurality of electrostatic adsorption members 74 and the like. The transport unit 96 attracts and holds the upper surface side (for example, the surface 11a side) of the workpiece 11 to transport the workpiece 11.

In the dividing step, as shown in FIG. 6, first, the upper surface side (in this embodiment, the surface 11a side) of the workpiece 11 is sucked and held by the transport unit 96. Next, the transport unit 96 is moved so that the lower surface side of the workpiece 11 (in the present embodiment, the back surface 11b side) is brought into contact with the upper surface 74a of the plurality of electrostatic adsorption members 74. At this time, the plurality of electrostatic adsorption members 74 and the workpiece 11 are arranged so that the planned division line 13 extending in the first direction of the workpiece 11 is aligned with the gap between the two adjacent electrostatic adsorption members 74. The relative position and orientation are adjusted by the transfer unit 96.

After that, by releasing the adsorption and holding of the workpiece 11 by the transport unit 96, the workpiece 11 can be mounted on the plurality of electrostatic adsorption members 74. Before mounting the workpiece 11 on the electrostatic adsorption member 74, the switch 92 is in a non-conducting (OFF) state. Further, the tension applied to the elastic sheets 76a and 76b is adjusted by the rotation drive sources 82a and 82b, and the cycle (repetition cycle) in which the electrostatic adsorption member 74 is arranged is extended in the first direction. Adjust to (repetition cycle).

After the workpiece 11 is placed on the plurality of electrostatic adsorption members 74, the workpiece 11 is adsorbed and held by the plurality of electrostatic adsorption members 74. FIG. 8 is a perspective view for explaining how the workpiece 11 is adsorbed and held, and FIG. 9A is a cross-sectional view for explaining how the workpiece 11 is adsorbed and held. be. As shown in FIG. 8, when the workpiece 11 is adsorbed and held, the switch 92 is switched from the non-conducting state to the conducting state, and the voltage of the DC power supply 94 is applied to the electrodes of each electrostatic adsorption member 74. ..

As a result, an electric field is generated around each electrostatic adsorption member 74, and as an effect, an electrostatic force acts between the workpiece 11 and each electrostatic adsorption member 74. As shown in FIGS. 8 and 9 (A), the workpiece 11 is attracted and held by each electrostatic adsorption member 74 by the force of static electricity. The electrostatic force acting between the workpiece 11 and each electrostatic adsorption member 74 includes Coulomb force, Johnson-Rahbek force, gradient force and the like.

In the present embodiment, when the workpiece 11 is mounted on the plurality of electrostatic adsorption members 74, the position of the planned division line 13 extending in the first direction corresponds to the gap between the two adjacent electrostatic adsorption members 74. It is aligned with the position. Therefore, when an electric field is generated around each electrostatic adsorption member 74, the plurality of parts (parts corresponding to the small pieces after division) divided by the plurality of planned division lines 13 extending in the first direction are electrostatically charged. It is attracted and held by the suction member 74.

After the workpiece 11 is adsorbed and held by the plurality of electrostatic adsorption members 74, the workpiece 11 is divided into a plurality of small pieces along a plurality of scheduled division lines 13 extending in the first direction. FIG. 9B is a cross-sectional view for explaining how the workpiece 11 is divided. Specifically, the rollers 80a and 80b are rotated in the direction of winding the elastic sheets 76a and 76b to increase the tension applied to the elastic sheets 76a and 76b (tension in the direction perpendicular to a predetermined direction).

That is, a pulling force is applied to the elastic sheets 76a and 76b in a direction perpendicular to a predetermined direction (here, a direction perpendicular to the first direction). As a result, a force is applied to each electrostatic adsorption member 74 so as to move each electrostatic adsorption member 74 perpendicularly to a predetermined direction and relatively away from each other.

As described above, the modified layer 19 serving as the starting point of division is formed on each of the plurality of planned division lines 13 extending in the first direction. The modified layer 19 is more brittle than the other regions of the workpiece 11. Therefore, as shown in FIG. 9B, the workpiece 11 is formed into a plurality of small pieces 21 along the plurality of scheduled division lines 13 extending in the first direction by the force transmitted through each electrostatic adsorption member 74. It is divided.

After the workpiece 11 is divided into a plurality of small pieces 21 along all the scheduled division lines 13 extending in the first direction, the workpiece 11 is rotated relative to the plurality of electrostatic adsorption members 74. Let me. Specifically, first, the upper surface side (in this embodiment, the surface 11a side) of the workpiece 11 held by the plurality of electrostatic suction members 74 is sucked and held by the transport unit 96. At the same time, the switch 92 is switched to the non-conducting state.

Next, the transport unit 96 is raised to relatively rotate each electrostatic adsorption member 74 and the workpiece 11. Specifically, two adjacent planned division lines 13 (second scheduled division lines) extending in a second direction (in the present embodiment, a direction perpendicular to the first direction) intersecting the first direction. The plurality of electrostatic suction members 74 and the workpiece 11 are relatively rotated so as to fit in the gaps of the electrostatic suction members 74. Then, the transport unit 96 is lowered so that the lower surface side of the workpiece 11 (in the present embodiment, the back surface 11b side) is brought into contact with the upper surface 74a of the plurality of electrostatic adsorption members 74 again.

After that, by releasing the adsorption and holding of the workpiece 11 by the transport unit 96, the workpiece 11 can be remounted on the plurality of electrostatic adsorption members 74. Before mounting the workpiece 11 on the electrostatic suction member 74 again, the tension applied to the elastic sheets 76a and 76b is adjusted by the rotation drive sources 82a and 82b, and the period in which the electrostatic suction members 74 are arranged (repeatedly). The cycle) is set to match the cycle (repetition cycle) in which the scheduled division lines 13 extending in the second direction are arranged.

After the workpiece 11 is placed on the electrostatic adsorption member 74 again, the workpiece 11 is adsorbed and held by the plurality of electrostatic adsorption members 74. Specifically, the switch 92 is switched from the non-conducting state to the conducting state, and the voltage of the DC power supply 94 is applied to the electrodes of each electrostatic adsorption member 74. As a result, an electric field is generated around each electrostatic adsorption member 74, and as an effect, an electrostatic force acts between the workpiece 11 and each electrostatic adsorption member 74. By the force of static electricity, the workpiece 11 is attracted and held by each electrostatic adsorption member 74.

In the present embodiment, by relatively rotating each electrostatic adsorption member 74 and the workpiece 11, the position of the planned division line 13 extending in the second direction is set to the position of the two adjacent electrostatic adsorption members 74. It is adjusted to the position corresponding to the gap. Therefore, when an electric field is generated around each electrostatic adsorption member 74, the plurality of parts (parts corresponding to the small pieces after division) divided by the plurality of planned division lines 13 extending in the second direction are electrostatically charged. It is attracted and held by the suction member 74.

After the workpiece 11 is adsorbed and held by the plurality of electrostatic adsorption members 74, the workpiece 11 is divided into a plurality of small pieces along a plurality of scheduled division lines 13 extending in the second direction. Specifically, the rollers 80a and 80b are rotated in the direction of winding the elastic sheets 76a and 76b to increase the tension applied to the elastic sheets 76a and 76b (tension in the direction perpendicular to a predetermined direction).

That is, a pulling force is applied to the elastic sheets 76a and 76b in a direction perpendicular to a predetermined direction (here, a direction perpendicular to the second direction). As a result, a force is applied to each electrostatic adsorption member 74 so as to move each electrostatic adsorption member 74 perpendicularly to a predetermined direction and relatively away from each other.

As described above, the modified layer 19 serving as the starting point of division is formed on each of the plurality of planned division lines 13 extending in the second direction. The modified layer 19 is more brittle than the other regions of the workpiece 11. Therefore, the workpiece 11 is divided into a plurality of small pieces along a plurality of scheduled division lines 13 extending in the second direction by the force transmitted through each electrostatic adsorption member 74. When the workpiece 11 is divided into individual chips along all the scheduled division lines 13, the division step ends.

As described above, in the chip manufacturing method according to the present embodiment, the workpiece 11 is directly held by the chuck table (holding table) 6 and the laser is applied only to the chip region 11c of the workpiece 11. A modified layer 19 is formed along the scheduled division line 13 by irradiating the beam 17, and then a plurality of electrostatic adsorption members (holding portions) 74 for each of the plurality of portions of the workpiece 11 separated by the scheduled division line 13 are formed. A method of dividing the workpiece 11 along a plurality of scheduled division lines 13 by applying a force to the plurality of electrostatic adsorption members 74 to relatively move them in a direction away from each other. Since 11 is divided into individual chips, it is not necessary to use an expand sheet to apply force to the workpiece 11 to divide it into individual chips. As described above, according to the chip manufacturing method according to the present embodiment, a plurality of chips can be manufactured by dividing the ferroelectric substrate, which is a plate-shaped workpiece 11, without using an expand sheet.

Further, in the chip manufacturing method according to the present embodiment, the laser beam 17 is irradiated only to the chip region 11c of the workpiece 11 to form the modified layer 19 along the scheduled division line 13, and the outer peripheral surplus region 11d is formed. Since the reinforcing portion in which the modified layer 19 is not formed is used, the chip region 11c is reinforced by this reinforcing portion. Therefore, the workpiece 11 is not divided into individual chips due to the force applied during transportation or the like, and the workpiece 11 cannot be appropriately transported.

The present invention is not limited to the description of the above embodiment and can be modified in various ways. For example, in the above embodiment, the back surface 11b side of the workpiece 11 is directly held by the chuck table 6 and the laser beam 17 is irradiated from the surface 11a side, but the surface 11a side of the workpiece 11 is chucked. It may be held directly on the table 6 and the laser beam 17 may be irradiated from the back surface 11b side.

FIG. 10 is a cross-sectional view for explaining a holding step according to a modified example. In the holding step according to this modification, as shown in FIG. 10, a chuck whose upper surface is formed of a porous sheet (porous sheet) 44 made of a flexible material represented by a resin such as polyethylene or epoxy, for example. It is preferable to use the table (holding table) 6.

In the chuck table 6, the upper surface 44a of the sheet 44 sucks and holds the surface 11a side of the workpiece 11. This makes it possible to prevent damage to the device or the like formed on the surface 11a side. This sheet 44 is a part of the chuck table 6 and is repeatedly used together with the main body of the chuck table 6 and the like.

However, the upper surface of the chuck table 6 does not need to be formed of the above-mentioned porous sheet 44, and is at least flexible enough not to damage the device or the like formed on the surface 11a side of the workpiece 11. It suffices if it is composed of materials. Further, it is desirable that the sheet 44 is configured to be detachable from the main body of the chuck table 6 and can be replaced when it is damaged or the like.

Further, in the above embodiment, the reinforcing portion removing step is performed after the carrying-out step and before the dividing step. However, for example, the reinforcing portion removing step may be performed after the laser machining step and before the carrying-out step. good.

Further, the step of removing the reinforcing portion can be omitted. In this case, for example, the range in which the modified layer 19 is formed in the laser machining step may be adjusted so that the width of the reinforcing portion is about 2 mm to 3 mm from the outer peripheral edge of the workpiece 11. Further, for example, a groove serving as a starting point of division may be formed in the reinforcing portion before the chip region 11c is divided in the division step. 11 (A) is a cross-sectional view for explaining the division step according to the modification, and FIG. 11 (B) shows the workpiece 11 before dividing the chip region 11c in the division step according to the modification. It is a top view which shows the state schematically.

In the division step according to the modification, the groove serving as the starting point of division is formed by using the cutting device 52 described above before the work piece 11 is divided into individual chips by the division device 72. Specifically, as shown in FIGS. 11A and 11B, the cutting blade 66 is cut into the outer peripheral excess region 11d (that is, the reinforcing portion) to form the groove 11e which is the starting point of the division. do. It is desirable that the groove 11e is formed, for example, along the planned division line 13. By forming such a groove 11e, the workpiece 11 can be divided by the outer peripheral surplus region 11d by the above-mentioned dividing device 72. In the division step according to the modification, the suction path 54c and the valve 60 of the chuck table 54 provided in the cutting device 52 can be omitted.

Further, in the division step of the above embodiment, the back surface 11b side of the workpiece 11 is directed downward, and the back surface 11b side is adsorbed and held by the plurality of electrostatic adsorption members 74. The surface 11a side may be directed downward, and the surface 11a side may be adsorbed and held by a plurality of electrostatic adsorption members 74.

Further, in the dividing device 72 of the above embodiment, the elastic sheets 76a, 76b, the rollers 80a, 80b, and the rotation drive sources 82a, 82b are used to apply a force to the plurality of electrostatic adsorption members 74. There are no particular restrictions on the structure of the applying mechanism that applies force. Similarly, in the dividing device 72 of the above embodiment, a plurality of electrostatic adsorption members 74 that attract and hold the workpiece 11 by the force of static electricity are used, but instead of the plurality of electrostatic adsorption members 74, It is also possible to use a plurality of suction members (holding portions) that suck and hold the workpiece 11 by a method such as vacuum suction.

In addition, the structures, methods, and the like according to the above-described embodiments and modifications 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 (work)
11a Front surface 11b Back surface 11c Chip area 11d Outer circumference surplus area 13 Scheduled division line (street)
15 regions 17 Laser beam 19 Modified layer (modified region)
19a 1st modified layer 19b 2nd modified layer 19c 3rd modified layer 2 Laser machining equipment 4 base 6 Chuck table (holding table)
6a Holding surface 6b Suction path 8 Horizontal movement mechanism 10 X-axis guide rail 12 X-axis movement table 14 X-axis ball screw 16 X-axis pulse motor 18 X-axis scale 20 Y-axis guide rail 22 Y-axis movement table 24 Y-axis ball screw 26 Y-axis Pulse motor 28 Y-axis scale 30 Support stand 32 Valve 34 Suction source 36 Support structure 38 Support arm 40 Laser irradiation unit 42 Camera 44 Seat (Porus sheet)
44a Top surface 52 Cutting device 54 Chuck table (holding table)
54a Holding surface 54b Suction path 54c Suction path 56 Valve 58 Suction source 60 Valve 62 Cutting unit 64 Spindle 66 Cutting blade 72 Splitting device 74 Electrostatic suction member (holding part)
74a Top surface (adsorption surface)
74b Lower surface 76a, 76b Elastic sheet (giving mechanism)
78 Adhesive 80a, 80b Roller (applying mechanism)
82a, 82b Rotational drive source (giving mechanism)
84a, 84b Core material 86a, 86b Conductive member 88 Insulation member 90 Wiring 92 Switch 94 DC power supply (power supply unit)
96 Transport unit

Claims (3)

A method for manufacturing a plurality of chips from a ferroelectric substrate having a chip region divided into a plurality of regions to be chips by a plurality of intersecting scheduled division lines and an outer peripheral surplus region surrounding the chip region. And
A holding step that holds the ferroelectric substrate directly on the holding table,
After performing the holding step, on the planned division line so as to position the focusing point of the laser beam having a wavelength that is transparent to the ferroelectric substrate inside the ferroelectric substrate held on the holding table. Along the same, the laser beam is irradiated only to the chip region of the ferroelectric substrate to form a modified layer along the planned division line of the chip region, and a modified layer is formed in the outer peripheral surplus region. Laser processing steps with no reinforcement and
After performing the laser machining step, a carry-out step of carrying out the ferroelectric substrate from the holding table and a carry-out step.
After performing the carry-out step, a division step of applying a force to the ferroelectric substrate to divide the ferroelectric substrate into individual chips is provided.
In the dividing step, a plurality of portions of the ferroelectric substrate is divided by several of the dividing line, respectively held in a plurality of holding portions, are relatively moved away from each other with respect to the holding portion of the plurality of A method for manufacturing a chip, which comprises dividing a ferroelectric substrate into individual chips by applying a force to divide the ferroelectric substrate into a plurality of planned division lines at once. The method for manufacturing a chip according to claim 1, further comprising a reinforcing portion removing step for removing the reinforcing portion after performing the laser machining step and before performing the dividing step. The upper surface of the holding table is made of a flexible material.
The method for manufacturing a chip according to claim 1 or 2, wherein in the holding step, the surface side of the ferroelectric substrate is held by the flexible material.

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