KR20180133215A - Method for manufacturing chip - Google Patents

Abstract

An objective of the present invention is to provide a method for manufacturing a chip capable of manufacturing a plurality of chips by dividing a plate-shaped workpiece without using an expand sheet. The method comprises: a laser processing step of irradiating a laser beam having transmittance to a silicon wafer only in a chip region along a line to be divided, forming a modified layer along the line to be divided in the chip region, and making an outer surplus region as a reinforcing unit in which the modified layer is not formed; and a dividing step of dividing the silicon wafer into individual chips by applying force to the silicon wafer. In the dividing step, the force is applied by one cooling or heating to divide the silicon wafer into individual chips.

Description

[0001] METHOD FOR MANUFACTURING CHIP [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing a chip by dividing a plate-shaped workpiece into a plurality of chips.

In order to divide a plate-shaped workpiece (workpiece) represented by a wafer into a plurality of chips, a transmissive laser beam is condensed inside the workpiece to form a modified layer (modified region) modified by multiphoton absorption (See, for example, Patent Document 1). Since the modified layer is weaker than other regions, it is possible to divide the workpiece into a plurality of chips starting from the modified layer by applying a force to the workpiece after forming the modified layer along the line to be divided have.

When a force is applied to the workpiece on which the modified layer is formed, for example, a method of expanding an expand sheet (expanded tape) having stretchability by attaching it to the workpiece is adopted (see, for example, Patent Document 2). In this method, the expand sheet is attached to the workpiece before the modified layer is formed on the workpiece by irradiating a laser beam, and after that, the modified layer is formed, and then the expand sheet is expanded so that the workpiece is divided into a plurality of chips .

Patent Document 1: JP-A-2002-192370 Patent Document 2: JP-A-2010-206136

However, in the method of expanding the expand sheet as described above, since the expanded sheet after use can not be used again, the cost for manufacturing the chip tends to increase. Particularly, a high-performance expanded sheet in which the adhesive material is difficult to remain on the chip is high in price, and therefore, when such an expanded sheet is used, the manufacturing cost is also increased.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to provide a method of manufacturing a chip by which a plurality of chips can be manufactured by dividing a plate-shaped workpiece without using an expanded sheet.

According to one aspect of the present invention, there is provided a method for manufacturing a semiconductor device, comprising: preparing a plurality of chips from a silicon wafer having a chip region divided into a plurality of regions to be chips by a plurality of lines to be divided, A holding step of holding a silicon wafer directly on a holding table; and a holding step of holding the light-converging point of a laser beam having a transmittance to a silicon wafer after the holding step, The laser beam is irradiated only to the chip area of the silicon wafer along the line to be divided so as to position the inside of the silicon wafer, and a modified layer is formed along the line to be divided of the chip area, A laser processing step of making the laser processing step as an unformed reinforcing part, And a dividing step of dividing the silicon wafer into individual chips by applying a force to the silicon wafer after carrying out the carrying out step, wherein the step of dividing the silicon wafer into individual chips And the silicon wafer is divided into individual chips by applying the force by cooling or heating the wafer.

In one embodiment of the present invention, after the laser processing step is performed, the step of removing the reinforcing portion may be further included before the dividing step. Further, in an 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 silicon wafer may be held by the flexible material.

In the method of manufacturing a chip according to an embodiment of the present invention, a laser beam is irradiated to only a chip region of a silicon wafer in a state in which a silicon wafer is directly held by a holding table to form a modified layer along a line to be divided, Since the silicon wafer is divided into individual chips by applying a force by cooling or heating once, it is not necessary to use an expand sheet to divide the silicon wafer into individual chips by applying a force to the silicon wafer. As described above, according to the method of manufacturing a chip according to an embodiment of the present invention, a silicon wafer, which is a plate-shaped workpiece, can be divided into a plurality of chips without using an expand sheet.

In the method of manufacturing a chip according to an embodiment of the present invention, a laser beam is irradiated to only a chip region of a silicon wafer to form a modified layer along a line to be divided, and the outer peripheral surplus region is made into a reinforcing portion Therefore, the chip region is reinforced by the reinforcing portion. Therefore, the silicon wafer is divided into individual chips by the force applied when carrying, etc., so that the silicon wafer can not be properly transported.

1 is a perspective view schematically showing a configuration example of a workpiece.
2 is a perspective view schematically showing a configuration example of a laser machining apparatus.
3 (A) is a cross-sectional view for explaining a holding step, and Fig. 3 (B) is a cross-sectional view for explaining a laser processing step.
Fig. 4A is a plan view schematically showing the state of the workpiece after the laser machining step, and Fig. 4B is a sectional view schematically showing the state of the workpiece after the laser machining step.
5A and 5B are cross-sectional views for explaining the reinforced portion removing step.
6 is a cross-sectional view for explaining the dividing step.
7 is a cross-sectional view for explaining a holding step according to a modification.
8A is a cross-sectional view for explaining a dividing step according to a modified example, and FIG. 8B is a diagram showing a state of a workpiece before dividing a chip area in a dividing step according to a modification, Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings. The manufacturing method of a chip according to the present embodiment is characterized in that the chip manufacturing method includes the steps of holding (see Fig. 3A), laser processing (see Fig. 3B, Fig. 4A and Fig. (Refer to FIG. 5 (A) and FIG. 5 (B)) and a dividing step (see FIG. 6).

In the holding step, a workpiece (work) having a chip area divided into a plurality of areas by the line to be divided and an outer peripheral surplus area surrounding the chip area is directly held by the chuck table (holding table). In the laser processing step, a laser beam of a wavelength having a transmittance to the workpiece is irradiated to form a modified layer (modified region) along the line to be divided in the chip region, and the outer peripheral surplus region is made into a reinforcing portion do.

In the carrying out step, the workpiece is carried out from the holding table. In the reinforced portion removing step, the reinforced portion is removed from the workpiece. In the dividing step, a force is applied by one cooling or heating to divide the workpiece into a plurality of chips. Hereinafter, a method of manufacturing a chip according to the present embodiment will be described in detail.

Fig. 1 is a perspective view schematically showing a structural example of a work (work) 11 used in the present embodiment. As shown in Fig. 1, the work 11 is made of a semiconductor such as silicon (Si), gallium arsenide (GaAs), indium phosphide (InP), gallium nitride (GaN), silicon carbide (Ferroelectric crystal) made of a dielectric (insulator) such as Al ₂ O ₃ , soda glass, borosilicate glass, or quartz glass, or a lithium tantalate (LiTa ₃ ) or lithium niobate (LiNb ₃ ) Wafer (substrate).

The surface 11a side of the work 11 is partitioned into a plurality of regions 15 which become chips by a plurality of lines 13 to be divided which intersect each other. In the following description, a substantially circular region including all of the plurality of regions 15 serving as 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 of the regions 15 in the chip region 11c is provided with an integrated circuit (IC), a micro electro mechanical system (MEMS), a light emitting diode (LED), a laser diode (LD), a photodiode, A SAW (Surface Acoustic Wave) filter, and a BAW (Bulk Acoustic Wave) filter.

A plurality of chips can be obtained by dividing the work 11 along the line 13 to be divided. Specifically, when the work 11 is a silicon wafer, for example, a chip functioning as a memory or a sensor can be obtained. When the work piece 11 is a gallium arsenide substrate, an indium phosphide substrate, or a gallium nitride substrate, a chip functioning as, for example, a light emitting element or a light receiving element can be obtained.

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

In the case where the work piece 11 is a ferroelectric substrate (ferroelectric crystal substrate) made of a ferroelectric such as lithium tantalate or lithium niobate, a chip functioning as, for example, a filter or an actuator can be obtained. The material, shape, structure, size, and thickness of the work 11 are not limited. Likewise, the type, quantity, shape, structure, size, arrangement, and the like of devices formed in the chip area 15 are not limited. A device may not be formed in the chip area 15.

In the method of manufacturing a chip according to the present embodiment, a plurality of chips are manufactured using a disk-shaped silicon wafer as the work 11. Specifically, first, the holding step of holding the work 11 directly on the chuck table is performed. Fig. 2 is a perspective view schematically showing a configuration example of a laser machining apparatus used in the present embodiment.

As shown in Fig. 2, the laser machining apparatus 2 includes a base 4 on which respective components are mounted. The upper surface of the base 4 is provided with a chuck table (holding table) 6 for holding and holding the work 11 in the X-axis direction (machining feed direction) and the Y-axis direction (indexing feed direction) A moving mechanism 8 is provided. The horizontal moving mechanism 8 includes a pair of X-axis guide rails 10 fixed on the upper surface of the base 4 and substantially parallel to the X-axis direction.

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

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

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

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

A support table 30 is provided on the front surface side (upper surface side) of the Y-axis moving table 22, and a chuck table 6 is disposed on the upper side of the support table 30. The surface (upper surface) of the chuck table 6 is a holding surface 6a for sucking and holding the side of the back surface 11b (or the surface 11a side) of the work 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 connected to the chuck table 6 through a suction path 6b (see FIG. 3A), a valve 32 (see FIG. 3A, etc.) And is connected to a suction source 34 (see FIG. 3A, etc.). A rotation driving source (not shown) is provided below the chuck table 6, and the chuck table 6 rotates around a rotation axis substantially parallel to the Z axis direction by the rotation driving source.

In the rear of the horizontal moving mechanism 8, a columnar support structure 36 is provided. A support arm 38 extending in the Y-axis direction is fixed to the upper portion of the support structure 36. The tip end of the support arm 38 is provided with a light-transmissive wavelength There is provided a laser irradiation unit 40 which emits pulses of a laser beam 17 (see FIG. 3 (B)) of a predetermined wavelength (for example, a wavelength) and irradiates the work 11 on the chuck table 6.

A camera 42 for picking up an image of the surface 11a side or the back surface 11b side of the work 11 is provided at a position adjacent to the laser irradiation unit 40. [ An image formed by picking up the work 11 and the like with the camera 42 is used for adjusting the position of the work 11 and the laser irradiation unit 40, for example.

The 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 properly processed.

3 (A) is a cross-sectional view for explaining the holding step. 3 (A), some of the constituent elements are represented by functional blocks. 3 (A), the back surface 11b of the work 11 is brought into contact with the holding surface 6a of the chuck table 6, for example. 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 work 11 is attracted to and held by the holding table 6 with the surface 11a side exposed on the upper side. 3 (A), the chuck table 6 directly holds the side of the back surface 11b of the work 11, as shown in Fig. 3 (A). That is, in the present embodiment, it is not necessary to attach an expand sheet to the work 11.

After the holding step, a laser processing step is carried out for irradiating the work 11 with a laser beam 17 having a wavelength that is transparent and forming a modified layer along the line 15 to be divided. 4A is a plan view schematically showing the state of the workpiece 11 after the laser machining step, and FIG. 4B is a cross-sectional view for explaining the laser machining step. FIG. (B) is a cross-sectional view schematically showing the state of the workpiece 11 after the laser machining step. In Fig. 3 (B), some of the components are represented by functional blocks.

In the laser processing step, first, the chuck table 6 is rotated so that the direction in which the to-be-divided line 13 to be a target extends, for example, is made parallel to the X-axis direction. Next, the chuck table 6 is moved to align the laser irradiation unit 40 on the extension of the line to be divided 13 to be a target. Then, as shown in Fig. 3 (B), the chuck table 6 is moved in the X-axis direction (i.e., the direction in which the intended line to be divided 13 extends).

Thereafter, at the timing when the laser irradiation unit 40 reaches immediately above one of the boundaries between the chip region 11c and the outer peripheral surplus region 11d existing at two positions on the target division target line 13, Irradiation of the laser beam 17 from the irradiation unit 40 is started. 3 (B), the laser beam is irradiated from the laser irradiation unit 40 disposed on the upper side of the work 11 toward the surface 11a of the work 11 17) are examined.

The irradiation of the laser beam 17 is performed such that the laser irradiation unit 40 irradiates the laser beam 17 to the other side of the boundary between the chip region 11c existing in two places on the intended division scheduled line 13 and the outer peripheral region 11d Continue until you reach the top. That is, in this case, the laser beam 17 is irradiated only in the chip region 11c along the target line to be divided 13.

The laser beam 17 is irradiated so as to position the light-converging point at a predetermined depth from the surface 11a (or the back surface 11b) of the inside of the work 11. As described above, by condensing the laser beam 17 having a transmittance with respect to the work 11 in the work 11, a part of the work 11 can be absorbed by the multi-photon absorption at the light- (Modified region) 19 serving as a starting point of the division can be formed. In this embodiment, since the laser beam 17 is irradiated only in the chip region 11c along the intended line to be divided 13, the laser beam 17 is modified only in the chip region 11c along the planned line to be divided 13 A layer 19 is formed.

After the modified layer 19 is formed at a predetermined depth along the line to be divided 13 of the target, the modified layer 19 is formed at the position of another depth along the intended line to be divided 13 in the same order ). Specifically, as shown in Fig. 4 (B), for example, the modified layer 19 is formed at three positions different in depth from the surface 11a (or the back surface 11b) of the work 11, The first reforming layer 19a, the second reforming layer 19b, and the third reforming layer 19c).

However, there is no particular limitation on the number or position of the reforming layer 19 formed along one line to be divided 13. For example, the number of the modified layers 19 formed along one planned line to be divided 13 may be one. It is preferable that the modified layer 19 is formed under a condition that a crack reaches the surface 11a (or the back surface 11b). Of course, the modified layer 19 may be formed under the condition that a crack reaches both the surface 11a and the back surface 11b. As a result, the work 11 can be more appropriately divided.

When the work 11 is a silicon wafer, the modified layer 19 is formed under the following conditions, for example.

Workpiece: Silicon wafer

Wavelength of laser beam: 1340 nm

Repetition frequency of laser beam: 90 kHz

Laser beam output: 0.1 W to 2 W

The moving speed of the chuck table (processing feed rate): 180 mm / s to 1000 mm / s, typically 500 mm / s

When the work 11 is a gallium arsenide substrate or an indium phosphide substrate, the modified layer 19 is formed under the following conditions, for example.

Workpiece: gallium arsenide substrate, indium phosphide substrate

Wavelength of laser beam: 1064 nm

Repetition frequency of laser beam: 20 kHz

Laser beam output: 0.1 W to 2 W

The moving speed (machining feed rate) of the chuck table is 100 mm / s to 400 mm / s, typically 200 mm / s

When the work 11 is a sapphire substrate, the modified layer 19 is formed under the following conditions, for example.

Workpiece: sapphire substrate

Wavelength of laser beam: 1045 nm

Repetition frequency of laser beam: 100 kHz

Laser beam output: 0.1 W to 2 W

The moving speed of the chuck table (processing feed rate): 400 mm / s to 800 mm / s, typically 500 mm / s

When the work 11 is a ferroelectric substrate made of a ferroelectric 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

Wavelength of laser beam: 532 nm

Repetition frequency of laser beam: 15 kHz

Laser beam output: 0.02 W to 0.2 W

The moving speed of the chuck table (machining feed rate): 270 mm / s to 420 mm / s, typically 300 mm / s

When the work 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

Wavelength of laser beam: 532 nm

Repetition frequency of laser beam: 50 kHz

Laser beam output: 0.1 W to 2 W

The moving speed of the chuck table (processing feed rate): 300 mm / s to 600 mm / s, typically 400 mm / s

When the work 11 is a gallium nitride substrate, the modified layer 19 is formed under the following conditions, for example.

Workpiece: Gallium nitride substrate

Wavelength of laser beam: 532 nm

Repetition frequency of laser beam: 25 kHz

Laser beam output: 0.02 W to 0.2 W

The moving speed of the chuck table (machining feed rate): 90 mm / s to 600 mm / s, typically 150 mm / s

When the work 11 is a silicon carbide substrate, the modified layer 19 is formed under the following conditions, for example.

Workpiece: Silicon carbide substrate

Wavelength of laser beam: 532 nm

Repetition frequency of laser beam: 25 kHz

The output of the laser beam is 0.02 W to 0.2 W, typically 0.1 W

(Moving feed rate) of the chuck table: 90 mm / s to 600 mm / s, typically 90 mm / s in the cleavage direction of the silicon carbide substrate and 400 mm / s in the clearing direction

After the necessary number of the reforming layers 19 are formed along the intended line to be divided 13, the above-described operation is repeated to form the modified layer 19 along all the lines 15 to be divided. As shown in Fig. 4 (A), when the modified layer 19 is formed along all the lines to be divided 13, the laser processing step is terminated.

In this embodiment, since the modified layer 19 is formed only in the chip region 11c along the line to be divided 13 and the modified layer 19 is not formed in the outer peripheral redundant region 11d, The strength of the work 11 is maintained by the region 11d. Thereby, the work 11 is not divided into individual chips due to the force applied when carrying or the like. Thus, the outer peripheral redundant region 11d after the laser processing step functions as a reinforcing portion for reinforcing the chip region 11 on which the modified layer 19 is formed.

In the present embodiment, since the modified layer 19 is not formed in the outer peripheral region 11d, the crack extending from the modified layer 19 reaches both the surface 11a and the backside 11b Even when the work 11 is completely divided, the chips do not fall off and are not dispersed. Generally, when the modified layer 19 is formed on the work 11, the work 11 expands in the vicinity of the modified layer 19. In the present embodiment, the expansion force generated by the formation of the reforming layer 19 is caused to act inwardly in a ring-like outer peripheral region 11d functioning as a reinforcing portion, .

After the laser processing step, a carrying-out step of carrying out the work 11 from the chuck table 6 is carried out. More specifically, the entire surface 11a of the work 11 is covered with a transport unit (not shown) capable of adsorbing and holding the entire surface 11a (or the back surface 11b) of the work 11, The valve 32 is opened to cut off the negative pressure of the suction source 34, and the work 11 is taken out. In the present embodiment, as described above, since the outer peripheral redundant region 11d functions as a reinforcing portion, the work 11 is divided into individual chips due to the force applied when carrying, etc., The work 11 can not be properly transported.

After the carrying-out step, a reinforced portion removing step for removing the reinforced portion from the work 11 is performed. 5A and 5B are cross-sectional views for explaining the reinforced portion removing step. 5 (A) and 5 (B), some of the components are represented by functional blocks. The reinforced portion removing step is performed, for example, by using the dividing device 52 shown in Figs. 5A and 5B.

The dividing device 52 includes a chuck table 54 for sucking and holding the work 11. A part of the upper surface of the chuck table 54 is a holding surface 54a for sucking and holding the chip area 11c of the work 11. The holding surface 54a is connected to the suction source 58 through a suction path 54b formed in the chuck table 54, a valve 56, and the like.

One end of a suction path 54c for sucking and holding the outer peripheral surplus region 11d (i.e., the reinforcing portion) of the work 11 is opened in another portion of the upper surface of the chuck table 54. [ The other end side of the suction passage 54c is connected to the suction source 58 through a valve 60 or the like. The chuck table 54 is connected to a rotation driving source (not shown) such as a motor and rotates around a rotation axis approximately parallel to the vertical direction.

A cutting unit 62 is disposed above the chuck table 54. The cutting unit 62 includes a spindle 64 which becomes a rotation axis approximately parallel to the holding surface 54a. On one end side of the spindle 64, an annular cutting blade 66 having abrasive grains dispersed therein is mounted.

A cutting blade 66 mounted on one end side of the spindle 64 is connected to a rotation driving source (not shown) such as a motor by a force transmitted from the rotation driving source to the other end side of the spindle 64, do. The cutting unit 62 is supported by, for example, a lifting mechanism (not shown), and the cutting blade 66 moves vertically by the lifting mechanism.

The upper surface of the chuck table 54 is provided with a cutting blade 66 for preventing contact with the cutting blade 66 at a position corresponding to the boundary between the chip region 11c and the outer peripheral region 11d of the work 11, (Not shown) is formed on the outer circumferential surface.

In the reinforced portion removing step, first, the back surface 11b of the work 11 is brought into contact with the holding surface 54a of the chuck table 54. Then, the valves 56 and 60 are opened and a negative pressure of the suction source 58 is applied to the holding surface 54a or the like. Thus, the work 11 is sucked and held by the chuck table 54 in a state in which the surface 11a side is exposed on the upper side. In this embodiment, as shown in Fig. 5 (A), the back surface 11b side of the work 11 is directly held by the chuck table 54. As shown in Fig. That is, also in this case, it is not necessary to affix the expand sheet to the work 11.

Next, the cutting blade 66 is rotated to be inserted at the boundary between the chip region 11c and the outer peripheral region 11d of the work 11. Further, as shown in Fig. 5 (A), the chuck table 54 is rotated around a rotation axis substantially parallel to the vertical direction. Thus, the work 11 can be cut along the boundary between the chip region 11c and the outer peripheral region 11d.

Thereafter, the valve 60 is closed to cut off the negative pressure of the suction source 58 with respect to the outer peripheral surplus region 11d of the work 11. Then, as shown in Fig. 5 (B), the outer peripheral surplus region 11d is removed from the chuck table 54. Fig. As a result, only the chip area 11c of the work 11 remains on the chuck table 54.

After the reinforced portion removing step, a dividing step of dividing the work 11 into individual chips is performed. Specifically, a large temperature difference is formed inside the work 11 (between the surface 11a and the back 11b), and the work 11 is divided by applying a force by thermal shock (thermal shock) . 6 is a cross-sectional view for explaining the dividing step. In Fig. 6, some of the constituent elements are represented by function blocks.

The dividing step is subsequently performed using the dividing device 52. [ As shown in Fig. 6, the dividing device 52 further includes a jetting nozzle (temperature difference forming unit) 68 disposed above the chuck table 54. As shown in Fig. In the dividing step of the present embodiment, a temperature difference required for generating a thermal shock is formed by spraying the cooling fluid 21 on the surface 11a of the work 11 from the injection nozzle 68. However, by spraying the heating fluid 21, a temperature difference necessary for generating a thermal shock may be formed.

As the cooling fluid 21, it is preferable to use a low-temperature liquid such as liquid nitrogen which can further remove heat by, for example, vaporization. As a result, the surface 11a side of the work 11 can be cooled quickly, and the required temperature difference can be easily formed. Here, the required temperature difference refers to a temperature difference at which a thermal shock exceeding the stress necessary for breaking the work 11 along the modified layer 19 can be obtained. The temperature difference is determined depending on, for example, the material and thickness of the work 11, the state of the modified layer 19, and the like.

However, there is no particular limitation on the kind and flow rate of the fluid 21. For example, a gas such as sufficiently cooled air or a liquid such as water may be used. When a liquid is used as the fluid 21, the liquid may be cooled to a temperature low enough not to freeze the liquid (for example, a temperature higher than the freezing point by about 0.1 to 10 DEG C).

The crack 23 is extended from the modified layer 19 due to thermal shock and the work 11 is moved along the line to be divided 13 to form a plurality of chips 25 ). As described above, in the present embodiment, the work 11 can be divided into individual chips 25 by applying a necessary force by one cooling. In the present embodiment, although the thermal shock is generated by rapidly cooling the work 11, a thermal shock may be generated by rapidly heating the work 11.

As described above, in the method of manufacturing a chip according to the present embodiment, the chip area 11c of the work 11 is directly held by the chuck table (holding table) 6 while the work 11 The modified layer 19 along the line to be divided 13 is formed by irradiating only the laser beam 17 on the chip 11 , It is not necessary to use an expand sheet for dividing the workpiece 11 into individual chips 25 by applying a force to the workpiece 11. [ As described above, according to the method of manufacturing a chip according to the present embodiment, a plurality of chips 25 can be manufactured by dividing a silicon wafer, which is a plate-shaped work 11, without using an expand sheet.

In the method of manufacturing a chip according to the present embodiment, the laser beam 17 is irradiated to only the chip region 11c of the work 11 to form the modified layer 19 along the line to be divided 13, Since the outer peripheral redundant region 11d is made into a reinforcing portion in which the reforming layer 19 is not formed, the reinforcing portion strengthens the chip region 11c. Therefore, the work 11 is divided into the individual chips 25 by the force applied when carrying, etc., so that the work 11 can not be properly transported.

The present invention is not limited to the description of the embodiments and the like, and can be variously modified. For example, in the holding step of the above embodiment, the side of the back surface 11b of the work 11 is directly held by the chuck table 6, and the laser beam 17 is irradiated from the side of the surface 11a. The laser beam 17 may be irradiated from the back surface 11b side by directly holding the surface 11a side of the laser beam 11 with the chuck table 6. [

7 is a cross-sectional view for explaining a holding step according to a modified example. In the holding step according to this modified example, as shown in Fig. 7, a porous sheet (porous sheet) 44 made of a flexible material typified by a resin such as polyethylene or epoxy, (Holding table) 6 is preferably used.

The chuck table 6 sucks and retains the surface 11a side of the work 11 from the upper surface 44a of the sheet 44. [ As a result, breakage of the device or the like formed on the surface 11a side can be prevented. 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.

The upper surface of the chuck table 6 does not have to be constituted by the porous sheet 44 described above and at least the device 11 formed on the surface 11a side of the work 11 is damaged It may be made of a flexible material. It is preferable that the seat 44 is detachably attached to the main body of the chuck table 6 so that it can be replaced when it is damaged.

In the above embodiment, the reinforced portion removing step is performed after the carrying out step and before the dividing step. For example, the reinforced portion removing step may be performed after the laser processing step and before the carrying out step. In the case of performing the reinforced portion removing step after the carrying out step and before the dividing step, there is no need to carry the workpiece 11 after the reinforced portion removing step, so that the workpiece 11 can be properly transported It is easy to avoid problems such as disappearance.

Also, the step of removing the reinforced portion may be omitted. In this case, it is preferable to adjust the range of forming the modified layer 19 in the laser processing step so that the width of the reinforced portion is about 2 mm to 3 mm from the outer peripheral edge of the work 11, for example. Further, for example, before the chip region 11c is divided in the dividing step, a groove serving as a starting point of division may be formed in the reinforcing portion. 8A is a cross-sectional view for explaining a dividing step according to a modified example, and FIG. 8B is a sectional view showing a part of the work 11 before the chip area 11c is divided in the dividing step according to the modified example. ) Of the present invention.

8 (A) and 8 (B), the cutting blade 66 is inserted into the outer peripheral surplus region 11d (i.e., the reinforcing portion) The groove 11e is formed. The groove 11e is preferably formed along the line to be divided 13, for example. By forming such grooves 11e, the work 11 can be divided into the outer peripheral surplus regions 11d by thermal shock. In the separation step according to the modified example, the suction passage 54c, the valve 60, and the like of the chuck table 54 can be omitted.

Other structures, methods, and the like of the above-described embodiments and modifications can be appropriately modified without departing from the scope of the present invention.

11: Workpiece (workpiece)
11a: surface
11b:
11c: chip area
11d: outer surplus area
13: Line to be divided (street)
15: area
17: laser beam
19: modified layer (modified region)
19a: First reformed layer
19b: second reformed layer
19c: third modified layer
21: Fluid
23: crack
25: Chip
2: Laser processing device
4: Base
6: Chuck table (holding table)
6a:
6b:
8: horizontal movement mechanism
10: X-axis guide rail
12: X-axis moving table
14: X-axis Ball Screw
16: X axis pulse motor
18: X axis scale
20: Y-axis guide rail
22: Y-axis moving table
24: Y-axis Ball Screw
26: Y-axis pulse motor
28: Y axis scale
30: Support
32: Valve
34: suction source
36: Support structure
38: Support arm
40: laser irradiation unit
42: camera
44: sheet (porous sheet)
44a: upper surface
52: Partitioning device
54: chuck table (holding table)
54a:
54b:
54c:
56: Valve
58: suction source
60: Valve
62: cutting unit
64: spindle
66: cutting blade
68: injection nozzle (temperature difference forming unit)

Claims (3)

A method of manufacturing a plurality of chips from a silicon wafer having a chip region divided into a plurality of regions to be a chip by a plurality of lines to be divided which intersect each other and an outer peripheral region surrounding the chip region,
A holding step of holding the silicon wafer directly to the holding table,
Only the chip area of the silicon wafer along the expected line to be positioned so as to position the light-converging point of the laser beam having the wavelength that is transmissive to the silicon wafer inside the silicon wafer held in the holding table after the holding step A laser processing step of irradiating a laser beam to form a modified layer along the line to be divided in the chip area and making the outer peripheral redundant area a reinforcing part in which the modified layer is not formed,
A carrying-out step of taking out the silicon wafer from the holding table after performing the laser processing step;
And a dividing step of dividing the silicon wafer into individual chips by applying a force to the silicon wafer after performing the carrying out step,
Wherein in the dividing step, the force is applied by one cooling or heating to divide the silicon wafer into individual chips. The method of manufacturing a chip according to claim 1, further comprising a step of removing the reinforcing portion after performing the laser processing step and before performing the dividing step. 3. The apparatus according to claim 1 or 2, wherein the upper surface of the holding table is made of a flexible material,
And in the holding step, the surface side of the silicon wafer is held with the flexible material.

Images