TWI774828B - processing methods - Google Patents

Abstract

[Problem] To provide a processing method capable of dividing the workpiece without colliding with the workpiece as compared with the prior art. [Solution] The processing method of the present invention includes: a laser processing step of performing laser processing on the workpiece (1) along the dividing line (2); and a dividing step of performing laser processing After the processing step, the workpiece (1) is divided by cutting a part of the thickness direction, so that the impact on the workpiece (1) can be reduced compared with the conventional processing method using a braking device or the like, Furthermore, the workpiece (1) can be favorably divided into individual wafers. In addition, in the dividing step, only a part of the workpiece (1) in the thickness direction needs to be cut with the cutting blade (26). Compared with the case of cutting, the processing feed rate can be increased, and the productivity of the wafer can be improved.

Description

processing methods

The present invention relates to a method for processing a workpiece in which the workpiece is divided into individual wafers.

A workpiece such as a wafer is divided into wafers each having elements by forming elements in regions demarcated by grid-like planned dividing lines on the surface thereof, and dividing along the planned dividing lines. As the method of dividing the workpiece into individual wafers, a method of dividing the workpiece by applying an external force to the workpiece after forming the starting point of division by laser processing the workpiece is employed.

As an example of laser processing, for example, there is a processing method of forming a submerged shield tunnel composed of pores and amorphous materials that shield the pores by irradiating the workpiece with pulsed laser light (refer to the following). Patent Document 1). In addition, as another example of laser processing, there is also a processing method in which a modified layer is formed inside the workpiece by irradiating a laser beam having a wavelength that is transparent to the workpiece (refer to the following Patent Document 2). ). Next, after the laser processing is performed on the workpiece, for example, the workpiece is divided by applying an external force to the workpiece using a braking device (refer to the following Patent Documents 3 and 4). [Prior Art Literature] [Patent Literature]

[Patent Document 1] JP 2014-221483 A

(The problem to be solved by the invention)

However, in the braking device, the blade (pressing member) is lowered from the upper side of the workpiece to collide with the workpiece to be divided by the blow. Therefore, if the braking is performed under inappropriate conditions, the workpiece may be damaged. There is a risk of damage to the object, and a segmentation method that does not cause collision to the workpiece is more desirable.

An object of the present invention is to provide a processing method capable of dividing the workpiece without colliding with the workpiece as compared with the prior art. (Means to Solve Problems)

The present invention relates to a processing method, which is a method for processing a workpiece with a predetermined dividing line set, and the processing method includes: a laser processing step of irradiating a laser beam that is transparent to the workpiece along the predetermined dividing line. A laser beam of a wavelength is used to perform laser processing on the workpiece; and a dividing step is to cut a part of the thickness direction of the workpiece along the predetermined dividing line with a cutting blade after the laser processing step is performed. The workpiece is divided along the planned dividing line, and the dividing step is to support both sides of the planned dividing line with support portions extending along the extending direction of the planned dividing line, and there is no need to support directly below the planned dividing line. to implement.

Preferably, in the aforementioned dividing step, the workpiece is placed on the holding platform having the suction and holding surface through a support jig having a size equal to or greater than that of the workpiece and having a size smaller than the suction and holding surface. On the suction and holding surface, a tape with a size larger than the suction and holding surface is attached to the held surface of the workpiece, and on the holding platform, the workpiece placed through the support jig is placed. In a state where the adhered tape covers the suction and holding surface, the workpiece is sucked and held by the holding platform.

In addition, it is preferred that in the aforementioned dividing step, the workpiece is directly attracted and held by a jig platform, the jig platform includes a support surface for supporting the workpiece, a groove corresponding to the aforementioned dividing line is formed, and Suction holes for sucking the workpiece are formed in each region defined by the grooves.

Preferably, the cross-sectional shape of the tip of the cutting blade is a V-shape. (effect of invention)

The processing method of the present invention includes: a laser processing step of performing laser processing on a workpiece along a line to be divided; and a dividing step of dividing the workpiece by cutting a part of the thickness direction of the workpiece, and the dividing step is a The two sides of the planned dividing line are supported by the support parts extending along the extending direction of the planned dividing line, and the support is not required directly below the planned dividing line. Therefore, compared with the conventional processing method, it is possible to reduce the impact on the workpiece. The collision can well divide the workpiece into individual wafers. In addition, in the dividing step, only a part of the workpiece in the thickness direction can be cut with the cutting blade. Therefore, compared with the case where the workpiece is completely cut in the thickness direction with the cutting blade, the machining feed rate can be increased. , the productivity of the wafer will be improved.

In the above-mentioned dividing step, on the holding platform having the suction and holding surface, the holding platform sucks and holds the workpiece through a support jig that has a size equal to or greater than that of the workpiece and has a size smaller than that of the suction and holding surface. The impact on the workpiece at the time of division can be reduced, and the workpiece can be favorably divided into individual wafers.

In addition, in the above-mentioned dividing step, the workpiece is directly sucked and held by a jig platform, and the jig platform includes a support surface for supporting the workpiece, and a groove corresponding to the above-mentioned dividing line is formed, and Suction holes for sucking the workpiece are formed in each area divided by grooves. Therefore, even if the workpiece is not attached with a tape, the impact on the workpiece during division can be reduced, and the workpiece can be processed. The object is well divided into individual wafers.

If the cross-sectional shape of the tip of the cutting blade is a V shape, even if the depth of incision in the thickness direction of the workpiece is shallow when the dividing step is performed, the laser-processed workpiece can be efficiently processed in the thickness direction. segmentation.

1 Object to be processed The object to be processed 1 shown in FIG. 1 is an example of a rectangular plate-shaped object to be processed, and a pattern is formed on the upper surface 1a of which grid-like dividing lines 2 are set. The lower surface of the workpiece 1 on the opposite side to the upper surface 1a is formed as, for example, a held surface 1b to which a tape 4 is attached. The material of the workpiece 1 is made of, for example, various glasses including quartz glass or borosilicate glass, LT/LN (lithium tantalate/lithium niobate), SiC (silicon carbide), Si (silicon), GaN (nitrogen) gallium), GaAs (gallium arsenide), sapphire, ceramics, etc. The workpiece 1 may be in the shape of a circular plate, not limited to the shape of a rectangular plate.

In the workpiece 1 shown in the present embodiment, the belt 4 is attached to the held surface 1b of the workpiece 1 by closing the opening of the annular frame 3 having an opening in the center, so that the belt 4 is passed through. And the frame 3 is formed as a whole to support. The tape 4 is not particularly limited, and for example, a stretched sheet of a two-layer structure in which an adhesive layer is laminated on a base material made of polyolefin, polyvinyl chloride, or the like is used. Although the to-be-processed object 1 shown in this embodiment is set with the line to be divided 2, the line to be divided 2 is not set and a to-be-processed object in which a pattern is not formed may be sufficient.

2. Processing method The laser processing apparatus 10 shown in FIG. 2 is an example of a laser processing apparatus for carrying out the later-described laser processing steps. The laser processing apparatus 10 has an apparatus base 100, and on the apparatus base 100 is provided: a holding table 11 that holds the workpiece 1 and is rotatable; The machining feeding means 13 for performing machining feeding; and the grading feeding means 14 for carrying out the grading feeding of the holding table 11 in the grading feeding direction (Y-axis direction).

The upper surface of the holding table 11 is formed as a holding surface 11a for holding the workpiece 1 . A plurality of frame holding means 12 for holding the above-mentioned frame 3 are arranged on the peripheral edge of the holding platform 11 . The frame holding means 12 is provided with: a frame mounting table 120 on which the frame 3 is mounted;

The machining feeding means 13 includes: a ball screw 130 extending in the X-axis direction; a motor 131 connected to one end of the ball screw 130; a pair of guide rails 132 extending parallel to the ball screw 130; The X-axis base 133 . The holding platform 11 is supported on one surface of the X-axis base 133 , a pair of guide rails 132 are slidably connected to the other surface of the X-axis base 133 , and a nut formed in the center of the X-axis base 133 is screwed with Ball screw 130. The ball screw 130 driven by the motor 131 rotates, whereby the X-axis base 133 can move along the guide rail 132 in the X-axis direction, and the holding platform 11 is processed and fed in the X-axis direction.

The stepwise feeding means 14 includes: a ball screw 140 extending in the Y-axis direction; a motor 141 connected to one end of the ball screw 140; a pair of guide rails 142 extending parallel to the ball screw 140; Y-axis base 143 . A pair of guide rails 142 are slidably connected to the other surface of the Y-axis base 143 , and are formed in the central portion of the Y-axis base 143 on one side of the Y-axis base 143 to support the holding table 11 through the processing and feeding means 13 . The nut is screwed with a ball screw 140. The ball screw 140 driven by the motor 141 rotates, whereby the Y-axis base 143 can move along the guide rail 142 in the Y-axis direction, and the holding platform 11 is graded and fed in the Y-axis direction.

A side wall 101 extending in the Z-axis direction is attached to the rear side in the Y-axis direction of the device base 100 . The front side of the side wall 101 is provided with the laser beam irradiation means 15 for performing laser processing on the workpiece 1 , and the elevating means 17 for raising and lowering the laser beam irradiation means 15 in the Z-axis direction. The laser beam irradiation means 15 includes: a housing 150 extending in the Y-axis direction; and a condenser 151 arranged at the front end of the housing 150 . Inside the casing 150 is accommodated an oscillator that oscillates a laser beam having a wavelength that transmits the workpiece 1 . A condenser lens (not shown) for condensing the laser beam oscillated by the oscillator is built in the condenser 151 .

At the front end of the housing 150 and at a position adjacent to the condenser 151 , the imaging means 16 for detecting the region to be irradiated with the laser beam (the line to divide 2 ) is disposed. The imaging means 16 is, for example, a camera with a built-in CCD image sensor. The imaging means 16 can detect the line to be divided 2 by capturing an image of the workpiece 1 held on the holding platform 11 from above, and performing image processing such as pattern matching.

The elevating means 17 includes: a ball screw 170 extending in the Z-axis direction; a motor 171 connected to one end of the ball screw 170; a pair of guide rails 172 extending parallel to the ball screw 170; Lifting plate 173 . The housing 150 is fixed to one surface of the lift plate 173 , a pair of guide rails 172 are slidably connected to the other surface of the lift plate 173 , and a ball screw 170 is screwed to a nut formed in the center of the lift plate 173 . The ball screw 170 driven by the motor 171 is rotated, whereby the lift plate 173 can move along the guide rail 172 in the Z-axis direction, so that the condenser 151 can be moved up and down, and the condensing position of the laser beam can be adjusted to the desired position s position.

(The first example of the laser processing step) Next, the laser processing apparatus 10 is used to irradiate a laser beam having a wavelength that is transparent to the workpiece 1 along the planned dividing line 2 to perform laser processing on the workpiece 1 . For example, using a condenser lens having spherical aberration, the object to be processed is irradiated with the laser beam in a state where longitudinal aberration occurs in the laser beam condensed by the condenser lens. The first example of the laser processing step is carried out under the following processing conditions 1, for example.

[Processing condition 1] Material of workpiece 1: Quartz glass Thickness of workpiece 1: 500μm Wavelength: 1064nm pulsed laser Average output: 2W Repetition frequency: 10kHz Machining feed rate: 100mm/s

As shown in FIG. 3, once the held surface 1b of the workpiece 1 to which the tape 4 is attached is placed on the holding surface 11a of the holding platform 11, and the frame 3 is placed on the frame placing table 120, the The upper surface of the frame 3 is pressed and fixed by the clip portion 121 . Next, the holding table 11 is moved in the X-axis direction by the processing feeding means 13 shown in FIG. 2 , and the planned dividing line 2 to be laser processed is detected by the imaging means 16 . After that, by the step-feeding means 14 , as soon as the alignment of the condenser 151 and the Y-axis direction of the planned dividing line 2 is performed, that is, by the raising and lowering means 17 , the condenser 151 is lowered in the direction of approaching the workpiece 1 . , and the position of the condensing point of the laser beam LB is positioned so as to extend in the thickness direction of the workpiece 1 .

While processing and feeding the holding table 11 in the X-axis direction at a predetermined processing feed speed (100 mm/s) by the processing and feeding means 13 shown in FIG. The planned dividing line 2 shown in 1 is irradiated with a laser beam LB having a wavelength (1064 nm) that is transparent to the work 1 from the upper surface 1a side of the workpiece 1, and along the planned dividing line 2, a plurality of laser beams are formed. The pore 5 shown in FIG. 4 is elongated in the irradiation direction of the beam LB. The pores 5 in the illustrated example form openings 6 in the held surface 1b of the workpiece 1, and are formed as fine holes that expand in diameter from the upper surface 1a toward the held surface 1b. Since the fine holes 5 are formed inside the workpiece 1, when the dividing step described later is performed, a relatively small external force is applied only from the upper surface 1a side, and the diameter-expanding side of the fine holes 5 (the held surface 1b where the opening 6 is formed) is applied. side) becomes easy to be widened, and the workpiece 1 can be divided well.

Around the pore 5 , a degenerated region 7 is formed around the pore 5 . The formation of the pores 5 by irradiating the laser beam LB is intermittently repeated along the extending direction of the line to divide 2, and the plurality of pores 5 are formed. A crack is formed in part between the adjacent pores 5 . As described above, the first example of the laser processing step is completed when a plurality of submerged shield tunnels constituted by pores 5 and modified regions 7 surrounding them are formed along all planned dividing lines 2 shown in FIG. 1 . The pores 5 are formed, for example, φ1 μm, and in the first example, the processing feed speed of the workpiece 1 is set to 100 mm/s, and the repetition frequency of the laser beam LB is set to 10 kHz, thereby dividing along the 10 μm pitch at 10 μm. The predetermined line 2 forms the fine hole 3 . In the first example, for convenience of explanation, the pores 5 or the degraded regions 7 are shown schematically in FIG. 4 to be clearly illustrated, but the pores 5 or degraded regions 7 formed by actual processing are not clearly understood. obvious.

In the first example of the above-mentioned laser processing step, in order to form a good shield tunnel inside the workpiece 1, as shown in FIG. 5, for example, the number of apertures (NA) of the condenser lens 152 is divided by the workpiece The value (S=NA/N) after the refractive index (N) of 1 is preferably set in the range of, for example, 0.05 to 0.2. Here, the relationship between the number of apertures (NA), the refractive index (N), and the value obtained by dividing the number of apertures (NA) by the refractive index (N) (S=NA/N) will be described. The laser beam LB passing through the condenser lens 152 is condensed at an angle θ with respect to the optical axis O, and sin θ at this time is the number of apertures (NA) of the condenser lens (N=sin θ). When the laser beam LB condensed by the condensing lens 152 is irradiated on the workpiece 1 , the laser beam LB is refracted by the angle θ to an angle α and condensed at the condensing point P. FIG. The angle α relative to the optical axis O varies depending on the refractive index (N) of the workpiece 1. The refractive index (N) is the value obtained by dividing sinθ by sinα (N=sinθ/sinα), so the number of openings ( The value (S=NA/N) obtained by dividing NA) by the refractive index (N) becomes sinα. Therefore, it is sufficient to set sinα in the range of 0.05 to 0.2 (0.05≦sinα≦0.2).

Next, the reason for setting the value (S=NA/N) obtained by dividing the number of apertures (NA) by the refractive index (N) in the range of 0.05 to 0.2 will be described. Specifically, for the workpiece 1 (refractive index (N): 1.45) made of quartz glass with a thickness of 500 μm, the number of apertures (NA) of the condenser lens 152 is set to, for example, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, forming a submerged shield tunnel with the above processing condition 1, to judge whether it is good or not. If the number of openings (N) is 0.05, the value (S=NA/N) obtained by dividing the number of openings (NA) by the refractive index (N) of the workpiece 1 becomes 0.035, and it is confirmed that it is formed inside the workpiece 1 The submerged shield tunnel is bad. In addition, if the number of openings (N) is set to 0.3, 0.35, and 0.4, respectively, the value (S=NA/N) obtained by dividing the number of openings (NA) by the refractive index (N) of the workpiece 1 becomes 0.207, 0.241, 0.276, the submerged shield tunnel became defective, and especially when the number of openings (N) was 0.35 and 0.4, the occurrence of holes was confirmed. On the other hand, if the number of openings (N) is set to 0.05, 0.1, 0.15, 0.2, and 0.25, respectively, the value (S=NA/N) obtained by dividing by the refractive index (N) of the workpiece 1 becomes 0.069, 0.103, 0.138, 0.172, it was confirmed that a good shield tunnel was formed inside the workpiece 1. Therefore, in the case of the condenser lens 152 in which the number of apertures (NA) is set in the range of 0.1 to 0.25, the value (S=NA/N) obtained by dividing the number of apertures (NA) by the refractive index (N) is 0.05 to 0.2 range, so it was confirmed that a good shield tunnel could be formed. In the first example of the laser processing step, longitudinal aberration occurs in the laser beam LB, and the object 1 is irradiated with the converging point P of the laser beam LB extending in the thickness direction of the object 1 . Laser beam LB. Each time the workpiece 1 is irradiated with one pulse of the laser beam LB, one fine hole 5 is formed. Therefore, only by processing and feeding the holding table 11 once, the workpiece 1 can be formed extending in the thickness direction of the workpiece 1 . Metamorphic zone 7. Among them, in the first example, in addition to using the condenser lens 152 having spherical aberration as described above, spherical aberration can also be generated by arranging a lens on the upstream side or downstream side of the condenser lens. The laser beam LB, which itself has a predetermined diffusion angle, can be oscillated by the oscillator to be condensed by the condenser lens.

(Second example of the laser processing step) In the first example of the above-mentioned laser processing step, the shield tunnel is formed inside the workpiece 1, but it is not limited to this case, and may be as shown in FIG. 6 , the modified layer 8 is formed inside the workpiece 1A. In the case of forming the shield tunnel in the first example, the condenser lens 152 having spherical aberration is used, but in the second example, the processing of forming the modified layer 8 in the workpiece 1A is performed, so Use a condenser lens without spherical aberration. That is, the second example of the laser processing step is performed using a laser processing apparatus (not shown) of an optical system different from the above-described laser processing apparatus 10 . The second example of the laser processing step is carried out under the following processing conditions 2, for example.

[Processing condition 2] Material of workpiece 1: Quartz glass Thickness of workpiece 1: 500μm Wavelength: 1064nm pulsed laser Average output: 0.2W Repetition frequency: 80kHz Processing feed rate: 200mm/s

Although not shown, the condenser is lowered in a direction close to the workpiece 1A, and the position of the condensing point of the laser beam is positioned at a predetermined depth close to the held surface 1b of the workpiece 1A. While the holding table is processed and fed in the X-axis direction at a predetermined processing feed speed (200 mm/s), along the planned dividing line 2, the workpiece 1 is irradiated from the upper surface 1a side of the workpiece 1 through the workpiece 1A. A laser beam having a specific wavelength (1064 nm), as shown in FIG. 6 , forms a modified layer 8 with reduced strength in the interior of the workpiece 1A along the extending direction of the dividing line 2 . Cracks 9 are generated in the thickness direction of the workpiece 1A from the end of the modified layer 8 . However, the output of the laser beam may be adjusted so that the crack 9 reaches the held surface 1b of the workpiece 1A.

The number of the modified layers 8 formed in the workpiece 1A is not particularly limited, and may be one layer or two or more layers. Therefore, when the plurality of modified layers 8 are formed inside the workpiece 1A, the condenser is raised, and the position of the condensing point of the laser beam is separated from the held surface 1b side of the workpiece 1A toward the upper surface 1a side. Two or more modified layers 8 are formed inside the workpiece 1A by positioning the condensing point of the laser beam on the upper surface 1a side at an even interval and irradiating the laser beam. In addition, the holding table may be processed and fed a plurality of times to form a plurality of layers of the modified layer 8, and the laser beam may be divided and the position of the condensing point may be positioned at a plurality of positions, the holding table may be The processing feed is performed to form the modified layer 8 of a plurality of layers. The second example of the laser processing step is completed when the modified layer 8 is formed along the extending direction of all the planned dividing lines 2 inside the workpiece 1A.

The cutting apparatus 20 shown in FIG. 7 is an example of a cutting apparatus for carrying out the dividing step to be described later. The cutting device 20 has a device base 200, and on the device base 200 is a rotatable holding table 21 having a suction and holding surface 21a for sucking and holding the workpiece 1; the holding table 21 is moved in the X-axis direction The machining feed means 23 for machining feed; the cutting means 25 for cutting the workpiece 1 ; and the step feed means 24 for the step feed of the cutting means 25 in the Y-axis direction. A frame holding means 22 for holding the frame 3 is arranged on the periphery of the holding platform 21 .

The machining feeding means 23 includes: a ball screw 230 extending in the X-axis direction; a motor 231 connected to one end of the ball screw 230; a pair of guide rails 232 extending parallel to the ball screw 230; X-axis base 233 . The holding table 21 is rotatably supported on one surface of the X-axis base 233 , a pair of guide rails 232 are slidably connected to the other surface of the X-axis base 233 , and a nut formed in the center of the X-axis base 233 A ball screw 230 is screwed. The ball screw 230 driven by the motor 231 rotates, whereby the X-axis base 233 can move along the guide rail 232 in the X-axis direction, and the holding platform 21 is processed and fed in the X-axis direction.

The stepwise feeding means 24 includes: a ball screw 240 extending in the Y-axis direction; a motor 241 connected to one end of the ball screw 240; a pair of guide rails 242 extending parallel to the ball screw 240; The movable base 243 . The cutting means 25 is supported on the upper part of the movable base 243 through the raising and lowering means 29 . On the other hand, a pair of guide rails 242 are slidably connected to the lower part of the movable base 243 , and a ball screw 240 is screwed to a nut formed in the center of the movable base 243 . The ball screw 240 driven by the motor 241 rotates, whereby the movable base 243 can be moved in the Y-axis direction along the guide rail 242, and the cutting means 25 can be stepped in the Y-axis direction.

The elevating means 29 is provided with at least a ball screw extending in the Z-axis direction, not shown; and a motor 290 connected to one end of the ball screw. The motor 290 is driven and the ball screw rotates, so that the cutting means 25 can be moved in the Z direction. The axis direction is raised and lowered. The imaging means 30 which detects the area|region (division plan line 2) which should be divided|segmented the to-be-processed object 1 is arrange|positioned on the path of the processing feed of the holding table 21. FIG. The imaging means 30 is, for example, a camera with a built-in CCD image sensor, and can detect the planned dividing line 2 by taking an image of the workpiece 1 held on the holding table 21 from above and performing image processing such as pattern matching.

The cutting means 25 includes at least a mandrel 250 having a shaft center in the Y-axis direction, a mandrel housing 251 that rotatably supports the mandrel 250 , and a mandrel 250 provided with an annular cutting edge attached to the front end of the mandrel 250 . Cutter 26 . The cutting means 25 is configured to rotate by the spindle 250 to rotate the cutting blade 26 at a predetermined speed.

The cutting edge of the cutting blade 26 is formed by combining a bonding material such as resin or metal with diamond or cubic boron nitride, etc., as shown in FIG. The shape is formed, for example, in a V shape. The tip angle 261 of the cutting blade 26 is preferably set in the range of 30° to 60°. As described above, with the cutting blade 26 having the tip portion formed in the V-shape, the divisibility of the workpiece 1 in which the fine hole 5 is formed becomes high. That is, when the cutting edge 260 of the cutting blade 26 is cut along the planned dividing line 2, even if the cutting depth in the thickness direction of the workpiece 1 is shallow, the opening 6 side of the fine hole 5 is widened, and the thickness direction can be efficiently cut. Divide the workpiece 1.

(First example of the dividing step) After the laser processing step is performed, the cutting device 20 cuts a part of the workpiece 1 in the thickness direction along the line 2 to be divided by the cutting blade 26, thereby dividing the workpiece. 1. The first example of the dividing step is performed, for example, while holding the workpiece 1 with the holding table 21 through the support jig 40 shown in FIG. 9 . In this embodiment, the case where the to-be-processed object 1 which is laser-processed in the 1st example of a laser processing step is divided|segmented is demonstrated.

The support jig 40 is formed in a rectangular plate shape, and includes: support parts 41 extending along the extension direction of the planned dividing line 2 to support the workpiece 1 on both sides of the planned dividing line 2; The groove 42 for the location of the predetermined line 2 . Both sides of the planned dividing line 2 refer to a portion of the workpiece 1 where the planned dividing line 2 is not formed, and a pair of outer sides 1c of the planned dividing line 2 are sandwiched therebetween.

The grooves 42 do not support the gap directly below the planned dividing line 2, and are formed to extend only in one direction in the example shown in the figure. The support jig 40 is made of a soft member such as rubber, urethane, etc., when the workpiece 1 is divided, the support jig 40 is easy to sink relative to the suction and holding surface 21a, and the workpiece 1 can be easily sunk. collision mitigation. In the support jig 40 configured as described above, the support parts 41 support both sides (a pair of outer sides 1 c ) of the planned dividing line 2 of the workpiece 1 and are positioned in the groove between the two support parts 41 The workpiece 1 can be held on the holding platform 21 directly below the planned dividing line 2 of the groove 42 without support.

In addition, it is preferable that the support jig 40 has a size equal to or greater than that of the workpiece 1 , and has a size smaller than the suction holding surface 21 a of the holding table 21 . The support jig 40 shown in this embodiment is formed to be approximately the same size as the workpiece 1, and can support the workpiece 1 without being damaged during division. Here, the size and shape of the support jig 40 may be appropriately changed according to the size or shape of the workpiece 1 to be divided.

When the workpiece 1 integrated with the frame 3 through the tape 4 is sucked and held on the holding table 21, the support jig 40 is placed on the suction and holding surface 21a of the holding table 21, and then the workpiece 1 is attached to the workpiece The object 1 is placed on the support jig 40 on the side of the tape 4 on the surface 1b to be held. At this time, the outer side 1 c of the planned dividing line 2 is positioned on the support portion 41 , and the groove 42 is positioned just below the planned dividing line 2 .

Next, the workpiece 1 is sucked and held by the holding platform 21 in a state where the tape 4 attached to the workpiece 1 placed on the support jig 40 covers the suction and holding surface 21 a. Specifically, if the suction force of the suction source (not shown) acts on the support jig 40 through the suction and holding surface 21a, as shown in FIG. It is peeled off from the held surface 1 b of the workpiece 1 by the suction force, and is in a state of being stuck following the shape of the groove 42 . That is, the opening 6 of the fine hole 5 located directly above the groove 42 is exposed, and the workpiece 1 is formed in a state in which it is not supported at all. The belt 4 can also be attached to the surface 1b to be held, but when the workpiece 1 is cut with the cutting blade 26, the portion directly above the groove 42 is not supported at all, and the splitability of the workpiece 1 even more. The distance H between the two support portions 41 sandwiching the groove 42 is preferably set to about 1/5 to 1/6 of the wafer size formed by dividing the workpiece 1 .

The line to be divided 2 is detected by the imaging means 30 shown in FIG. 7 , and the alignment of the line to be divided 2 and the cutting blade 26 is performed. Next, the cutting blade 26 is rotated while the holding table 21 is processed and fed in the X-axis direction at a predetermined processing feed speed by the processing feeding means 23 , and the cutting blade 26 is moved from the workpiece by the lifting and lowering means 29 at the same time. The upper surface 1a of the object 1 is cut by a predetermined cutting depth L, and a part of the workpiece 1 in the thickness direction is cut. When the tip angle 261 of the cutting blade 26 shown in FIG. 8 is set to, for example, 60°, the cutting depth L is preferably set to about 1/5 (about 100 μm) of the thickness of the workpiece 1 . By cutting a part of the workpiece 1 in the thickness direction as described above, the opening 6 side of the enlarged diameter of the fine hole 5 is widened, and the portion located above the groove 42 is pressed downward, and the workpiece cannot withstand external force. 1 is divided. Among them, the sharper the front end angle 261 of the cutting blade 26 is, the more the splitability of the workpiece 1 is improved, but the wear amount of the cutting blade 26 is larger, so if the front end angle 261 is adjusted according to the material of the workpiece 1, or The cut-in depth L is sufficient.

After cutting with the cutting blade 26 along the planned dividing line 2 extending in one direction of the workpiece 1, the workpiece 1 is once removed from the support jig 40 and rotated by 90°, and the groove 42 is positioned in the The workpiece 1 is placed on the support jig 40 again after the cut just below the planned dividing line 2 . Thereafter, in the same manner as above, the workpiece is sucked and held by the holding platform 21 while the tape 4 attached to the workpiece 1 placed on the support jig 40 covers the suction and holding surface 21a. 1. Divide the workpiece 1 into individual wafers while performing the same cutting as described above along the line to be divided 2 . The grooves 42 of the support jig 40 may also be formed in a lattice shape corresponding to the lattice-shaped planned dividing lines 2 . At this time, after cutting along the planned dividing line 2 extending in one direction of the workpiece 1, the holding table 21 is rotated by 90°, thereby changing the direction of the uncut planned dividing line 2, along the dividing plan. The wire 2 may be cut in the same manner as described above.

The cross-sectional shape of the tip portion of the cutting blade 26 shown in this embodiment is a V shape, but it is not limited to this shape. For example, as shown in FIG. 11( a ), the dividing step may be performed using a cutting blade 27 having an inclined tapered outer peripheral surface 270 on one surface and a V-shaped cross-sectional shape of the tip portion. Further, as shown in FIG. 11( b ), the dividing step may be performed using the cutting blade 28 having a flat cutting edge 280 in the shape of the distal end portion. It is preferable to set the depth of cut when the dividing step is performed using the cutting blade 28 to about 1/2 (about 250 μm) of the thickness of the workpiece 1 .

(Second example of the dividing step) In the dividing step, for example, the jig stage 50 shown in FIG. 12 may be used for implementation. The jig stage 50 includes a support surface 51 for supporting the workpiece 1 , grooves 52 corresponding to the planned dividing lines 2 are formed, and suction holes 53 for sucking the workpiece 1 are formed in each region defined by the grooves 52 . The jig platform 50 is fixed on the jig base 54 shown in FIG. 13 . Inside the jig base 54, a suction passage 55 that communicates with the suction hole 53 is formed. The suction path 55 is connected to the suction source 57 through the valve 56 . By opening the valve 56 , an attractive force can be applied to the support surface 51 through the suction hole 53 . In addition, the jig base 54 is formed with a suction hole 58 for sucking and holding the jig stage 50 . The suction hole 58 is connected to the suction source 57a through the valve 56a. By opening the valve 56a, the jig table 50 can be sucked and held by the suction hole 58 acting on the upper surface of the jig base 54 with an attractive force. As described above, the jig stage 50 formed integrally with the jig base 54 functions as a holding stage for directly sucking and holding the workpiece 1 .

When the dividing step is performed using the jig stage 50 , as shown in FIG. 14 , the workpiece 1 having the fine holes 5 formed along the line to be divided 2 is placed on the jig stage 50 from the held surface 1 b side. At this time, the opening 6 of the fine hole 5 is positioned above the groove 52 of the jig stage 50 . Next, the valve 56 is opened, the suction hole 53 is communicated with the suction source 57 through the suction passage 55 , and the suction force acts on the support surface 51 of the jig stage 50 . Thereby, the workpiece 1 is directly sucked and held by the jig stage 50 . In the second example of the dividing step, since the workpiece 1 can be directly sucked and held by the jig table 50, the above-mentioned tape 4 may not be used.

Similar to the first example of the dividing step, while rotating the cutting blade 26 in the direction of arrow A, for example, the cutting blade 26 is cut from the upper surface 1a of the workpiece 1 at a predetermined cutting depth to cut the workpiece 1 in the thickness direction. a part of. The opening 6 side of the enlarged diameter of the fine hole 5 is widened, and the portion located above the groove 52 is pressed downward, and the workpiece 1 that cannot withstand the external force is divided. Next, the same cutting as described above is performed along all the planned dividing lines 2 to divide the workpiece 1 into individual wafers.

As described above, in the machining method of the present invention, since the dividing step for dividing by cutting a part of the workpiece 1 in the thickness direction is provided, compared with the conventional machining method using a braking device or the like, it is possible to The impact on the workpiece 1 is reduced, and the workpiece 1 can be favorably divided into individual wafers. In addition, in the dividing step, since only a part of the workpiece 1 in the thickness direction is cut with the cutting blade 26, the cutting blade 26 can cut the workpiece 1 completely in the thickness direction. With the processing feed rate, the productivity of the wafer will be improved. In the first example of the dividing step, the holding table 21 having the suction and holding surface 21a is held by a support jig 40 having a size equal to or greater than that of the workpiece 1 but smaller than the suction and holding surface 21a. The stage 21 attracts and holds the workpiece 1, so that the impact on the workpiece 1 at the time of division can be reduced, and the workpiece 1 can be favorably divided into individual wafers. In addition, in the second example of the dividing step, the jig platform 50 is configured to directly suck and hold the workpiece 1 without the tape 4 attached thereto, so that the impact on the workpiece 1 at the time of dividing can be reduced. , the workpiece 1 can be favorably divided into individual wafers.

1. 1A‧‧‧Workpiece 1a‧‧‧Top surface 1b‧‧‧Retained surface 1c‧‧‧Outside 2‧‧‧Partitioning line 3‧‧‧Frame 4‧‧‧Tape 5‧‧‧Slim hole 6‧‧‧Opening 7‧‧‧Modified area 8‧‧‧Modified layer 9‧‧‧Crack 10‧‧‧Laser processing device 100‧‧‧Device base 101‧‧‧Sidewall 11‧‧‧Holding platform 11a ‧‧‧Holding surface 12‧‧‧Frame holding means 120‧‧‧Frame mounting table 121‧‧‧Clamp part 13‧‧‧Processing feeding means 130‧‧‧Ball screw 131‧‧‧Motor 132‧‧‧Guide rail 133 ‧‧‧X axis base 14‧‧‧Grading feed means 140‧‧‧Ball screw 141‧‧‧Motor 142‧‧‧Guide rail 143‧‧‧Y axis base 15‧‧‧Laser beam irradiation means 150‧ ‧‧Housing 151‧‧‧Condenser 152‧‧‧Condenser lens 16‧‧‧Camera means 17‧‧‧Lifting means 170‧‧‧Ball screw 171‧‧‧Motor 172‧‧‧Guide rail 173‧‧‧ Lifting Plate 20‧‧‧Cutting Device 200‧‧‧Device Base 21‧‧‧Holding Platform 21a‧‧‧Holding Surface 22‧‧‧Frame Holding Means 23‧‧‧Machining Feeding Means 230‧‧‧Ball Screws 231‧ ‧‧Motor 232‧‧‧Guide rail 233‧‧‧X-axis base 24‧‧‧Grading feed method 240‧‧‧Ball screw 241‧‧‧Motor 242‧‧‧Guide rail 243‧‧‧Moveable base 25‧‧ ‧Cutting means 250‧‧‧Spindle 251‧‧‧Shell 26, 27, 28‧‧‧Cutting tools 260, 280‧‧‧Tool tip 261‧‧‧Front end angle 270‧‧‧Outer peripheral surface 29‧‧‧Lifting means 290‧‧‧Motor 30‧‧‧Camera means 40‧‧‧Supporting fixture 41‧‧‧Supporting part 42‧‧‧Groove 50‧‧‧Judge platform 51‧‧‧Supporting part 52‧‧‧Groove 53 ‧‧‧Suction hole 54‧‧‧Judge base 55‧‧‧Suction path 56, 56a‧‧‧Valve 57, 57a‧‧‧Suction source 58‧‧‧Suction hole H‧‧‧distance L‧‧‧cut Depth LB‧‧‧laser beam O‧‧‧optical axis P‧‧‧focusing point

FIG. 1 is a perspective view showing an example of a workpiece. Fig. 2 is a perspective view showing the configuration of an example of a laser processing apparatus. Figure 3 is a sectional view showing the steps of laser processing. Fig. 4 is a partial enlarged cross-sectional view of the workpiece after the first example of the laser processing step is carried out. Fig. 5 is an explanatory diagram illustrating the relationship between the number of apertures of the condenser lens, the refractive index of the workpiece, and the value obtained by dividing the number of apertures by the refractive index. Fig. 6 is a partial enlarged cross-sectional view of the workpiece after the second example of the laser processing step is carried out. Fig. 7 is a perspective view showing the configuration of an example of a cutting device. Fig. 8 is a partially enlarged cross-sectional view showing the structure of the cutting blade. Fig. 9 is a perspective view showing the state in which the workpiece is placed on the holding platform through the support jig in the first example of the dividing step. Fig. 10 is a partially enlarged cross-sectional view showing the first example of the dividing step. Fig. 11(a) is an enlarged cross-sectional view showing the second example of the cutting blade. (b) is an enlarged cross-sectional view showing the third example of the cutting blade. Fig. 12 is a perspective view showing the structure of the jig platform. Fig. 13 is a cross-sectional view showing the structure of the jig table fixed to the jig base. Fig. 14 is a sectional view showing a second example of the dividing step.

1‧‧‧Processing

1a‧‧‧above

1b‧‧‧Retained surface

4‧‧‧Tape

5‧‧‧pore

6‧‧‧Opening

7‧‧‧Deterioration area

26‧‧‧Cutting knives

40‧‧‧Support fixture

41‧‧‧Support Department

42‧‧‧Groove

260‧‧‧ tip

H‧‧‧distance

L‧‧‧cut depth

Claims (2)

A processing method of a workpiece having a predetermined dividing line set, the processing method comprising: a laser processing step of attaching a tape to a held surface of the workpiece, and passing through the tape The object to be processed is held on a holding platform of the laser processing apparatus, a laser beam having a wavelength that is transparent to the object to be processed is irradiated along the predetermined line for dividing, and laser processing is performed on the object to be processed; and a dividing step is performed in After the laser processing step is carried out, the held surface of the workpiece is held on the suction and holding surface of the holding platform of the cutting device, and a part of the thickness direction of the workpiece is cut with the cutting blade along the planned dividing line. The planned dividing line divides the workpiece, and a tape having a size larger than the suction and holding surface of the holding platform of the cutting device is attached to the held surface of the workpiece, and in the dividing step, a tape is attached to the holding surface. The suction and holding surface is provided with support portions extending to both sides of the planned dividing line along the extending direction of the planned dividing line, and has a size equal to or greater than the workpiece to be processed and smaller than the dimension of the suction and holding surface. A support jig is used to place the workpiece on the suction and holding surface through the support jig, and the part directly below the planned dividing line is formed in an unsupported state. The workpiece is sucked and held on the holding platform in a state where the tape of the workpiece covers the suction and holding surface, whereby the tape between the support parts is peeled off from the held surface of the workpiece to be held by the workpiece. Processed product segmentation. The processing method according to claim 1, wherein the cross-sectional shape of the tip of the cutting blade is a V-shape.

Images