CN102655120B - Laser processing device - Google Patents

Abstract

The present invention provides a laser processing method and a laser processing device of a wafer capable of forming a degenerated layer along the spacer inside the wafer without increasing the width of the spacer or sticking a dicing tape on the surface of the wafer. The laser processing method of the wafer forms a metamorphic layer along the spacer inside the wafer, and the surface of the wafer is formed with a plurality of spacers in a grid pattern and devices are formed in a plurality of regions divided by the plurality of spacers , the laser processing method of the wafer includes: a wafer supporting process, in which the back surface of the wafer is pasted to a dicing tape mounted on a ring frame; and a metamorphic layer forming process, in which the metamorphic layer forming process In this method, laser light having a wavelength that is transparent to the dicing tape and the wafer is irradiated from the dicing tape side with a focus point inside the wafer along the lanes to form a degenerated layer inside the wafer along the lanes.

Description

Laser processing device

technical field

The present invention relates to a laser processing method and a laser processing apparatus for forming a degenerated layer inside the wafer along the streets, the wafer is formed with a plurality of streets in a grid pattern on the surface, and the wafer is made of multiple streets. Devices such as micro-electro-mechanical systems (MEMS) are formed in a plurality of regions divided by the bar intervals.

Background technique

In the semiconductor device manufacturing process, a plurality of regions are divided on the surface of a substantially disc-shaped semiconductor wafer by dividing lines called streets arranged in a grid pattern, and ICs are formed in the divided regions ( Integrated Circuit: integrated circuit), LSI (LargeScaleIntegration: large scale integrated circuit), microelectromechanical system (MEMS) and other devices. Then, the region in which the devices are formed is divided by cutting the semiconductor wafer along the lanes, thereby manufacturing individual devices.

The cutting of the wafer along the lanes is generally performed by a cutting device called a dicer. This cutting device includes: a chuck table for holding a workpiece such as a wafer; a cutting member including a cutting tool for cutting the workpiece held on the chuck table; and a cutting feed A member for cutting and feeding a chuck table and a cutting member facing each other, the cutting device cutting the chuck table while rotating a cutting tool and supplying cutting fluid to a cutting portion cut by the cutting tool Feed, thereby, cut along the lanes of the wafer.

However, since the cutting tool has a thickness of about 20 [mu]m to 30 [mu]m, the width of the street dividing the device needs to be about 50 [mu]m. Therefore, there is a problem that the ratio of the area occupied by the partition lanes increases and the productivity is poor.

On the other hand, as a method of dividing a wafer along the lanes, there has been proposed a method in which a pulsed laser beam having a wavelength that is transparent to the wafer is irradiated along the lanes by aligning the converging point with the inside of the wafer. A degenerated layer serving as a fracture origin is continuously formed in the interior of the wafer along the lanes, and an external force is applied along the lanes where the degenerated layer serving as a fracture origin is formed to cause a decrease in strength, whereby the wafer is divided along the lanes. (For example, refer to Patent Document 1.)

Patent Document 1: Japanese Patent No. 3408805

As a method of continuously forming a degenerated layer as a fracture starting point inside the wafer along the partition road, and applying an external force along the partition road where the degenerated layer serving as a fracture starting point is formed to cause a decrease in strength, the wafer is divided. The following method is proposed: from the back side of the wafer on which the roads are not formed, the focusing point of the laser light is positioned inside the area corresponding to the roads and the laser light is irradiated to form a degenerated layer, and then the back side of the wafer is pasted on the dicing surface. The belt divides the wafer by applying an external force to the wafer in which the degenerated layer is formed along the lanes. However, when a wafer having a degenerated layer formed inside along the lanes is attached to a dicing tape, there is a problem that the wafer is cracked along the lanes.

On the other hand, the above-mentioned problem can be avoided by carrying out the following method: in the state where the back surface of the wafer is attached to the dicing tape mounted on the ring frame, the laser light is condensed from the surface side of the wafer in the interior of the lane to form a degenerated layer, but there is the following problem: the width of the irradiated region of the laser light needs to reach about 20% to 30% of the thickness of the wafer, for example, in a wafer with a thickness of 400 μm formed with a microelectromechanical system (MEMS), it needs to be about 100 μm If the width of the spacer is large, the restriction on the design of the wafer is relatively large, and the productivity is poor.

In addition, if the above-mentioned problem can be solved by adopting the following method: in the state where the surface of the wafer is attached to the dicing tape mounted on the ring frame, the laser light is condensed from the back side of the wafer in the interior of the lane to form the altered layer, However, there is a problem that if the surface of the device is attached to a dicing tape on a wafer on which devices such as microphones, acceleration sensors, and pressure sensors are formed by microelectromechanical systems (MEMS), the adhesive will adhere to the microelectromechanical system (MEMS). Electromechanical system (MSMS) and damage the device.

Contents of the invention

The present invention is accomplished in view of the above-mentioned circumstances, and its main technical task is to provide a laser processing method and a laser processing device for a wafer, which can be made on the surface of the wafer without increasing the width of the spacer or sticking a dicing tape on the surface of the wafer. Metamorphic layers are formed internally along septal channels.

In order to solve the above-mentioned main technical problems, according to the present invention, there is provided a laser processing method for forming a degenerated layer along the spacer lanes inside the wafer, the surface of which is formed with a plurality of spacers in a grid pattern. lanes, and the wafer is formed with devices in a plurality of regions divided by the plurality of spaced lanes,

The laser processing method of the wafer is characterized in that,

The laser processing method of described wafer comprises:

a wafer supporting process in which the back side of the wafer is pasted to a dicing tape mounted on a ring frame; and

A modified layer forming step in which the laser light having a wavelength that is transparent to the dicing tape and the wafer is irradiated along the partition lanes from the dicing tape side with a focused point positioned inside the wafer, and A degenerated layer is formed along the spacer lanes inside the wafer.

Furthermore, according to the present invention, there is provided a laser processing apparatus for irradiating laser light along the spaced roads to the inside of a wafer to form a degenerated layer along the spaced roads inside the wafer, the wafer being formed on the surface a plurality of lanes are formed in a grid pattern, and the wafer is formed with devices in a plurality of regions divided by the lanes,

The laser processing device is characterized in that,

The laser processing apparatus includes: a chuck table having a wafer holding portion and an annular frame holding portion for performing processing on a wafer attached to a dicing tape attached to the ring frame. holding, the ring-shaped frame holding part is provided on the outer side of the wafer holding part in the outer peripheral direction, and has a frame holding surface for holding the ring-shaped frame; the condenser for irradiating laser light having a wavelength that is transparent to the wafer held on the chuck table and the dicing tape; and a moving member for making the chuck table and the dicing tape The concentrator moves relatively,

The wafer holding portion of the chuck table is formed of a transparent member,

A plurality of suction holes for sucking the ring frame through the cutting tape are formed on the frame holding surface of the ring frame holding part of the chuck table, and the ring frame a plurality of suction holes for suction holding the dicing band in the area between the frame and the outer periphery of the wafer,

The concentrator of the laser light irradiating means is configured to irradiate the wafer with laser light from the lower side of the wafer holding part of the chuck table through the wafer holding part and the dicing tape.

In the laser processing method of the wafer of the present invention, the back surface of the wafer is attached to the dicing tape attached to the ring frame, and the laser beam having a wavelength that is transparent to the dicing tape and the wafer is used to position the focal point from the dicing tape side. Irradiate inside the wafer and along the spaced roads, so that a degenerated layer is formed inside the wafer along the spaced roads, so there is no situation where the pulsed laser light is irradiated to the devices formed on the surface of the wafer. This eliminates the need for a street having a width of 20% to 30% of the thickness of the wafer, so there is no restriction on the width of the street in terms of wafer design. Moreover, since the back side of the wafer is pasted on the dicing tape from the beginning, there is no need to turn over the front and back side after forming the deteriorated layer and stick it again, so that the wafer will crack along the separation lane when the wafer is pasted again. Problems are avoided.

Moreover, the laser processing apparatus of the present invention is configured to include: a chuck table provided with a holding portion for holding a wafer attached to a dicing tape attached to an annular frame; a condenser of laser light having a wavelength that is transmissive with respect to the wafer and the dicing tape held on the chuck table; and a moving member for moving the chuck table relative to the condenser, the chuck The holding portion of the workbench is formed by a transparent member, and the light collector of the laser light irradiation member is configured to irradiate the laser light to the wafer through the wafer holding portion and the dicing tape from the underside of the wafer holding portion of the chuck table, so that the above-mentioned can be implemented. The laser processing method of a wafer can obtain the above-mentioned effects.

Description of drawings

Fig. 1 is a perspective view of a laser processing device constructed according to the present invention.

Fig. 2 is a perspective view of a wafer subjected to laser processing by the laser processing method of a wafer according to the present invention.

3 is a perspective view showing a state in which the back surface of the wafer is attached to the dicing tape attached to the ring frame by carrying out the wafer supporting step in the laser processing method of the wafer according to the present invention.

4 is an explanatory diagram of a wafer supporting step in the laser processing method of a wafer according to the present invention.

Fig. 5 is an explanatory diagram of an alignment step in the laser processing method of a wafer according to the present invention.

(a), (b) and (c) of FIG. 6 are explanatory views of the altered layer forming step in the laser processing method of the wafer according to the present invention.

(a) and (b) of FIG. 7 are explanatory views of a modified layer forming step in the laser processing method of a wafer according to the present invention.

Fig. 8 is a perspective view of a tape expanding device used in the wafer breaking step in the laser processing method for wafers according to the present invention. In the wafer breaking step, the altered layer is formed along the wafer after the altered layer forming step The spacer is disconnected.

(a) and (b) of FIG. 9 are explanatory views of a wafer breaking process performed by the tape expansion device shown in (a) and (b) of FIG. 7 .

Fig. 10 is an explanatory diagram of a pick-up process performed by the tape expansion device shown in (a) and (b) of Fig. 7 .

Label description

1: Laser processing device;

2: Stationary base;

3: The first movable base;

30: the first moving member;

4: The second movable base;

40: spot adjustment member;

5: The third movable base;

50: the second moving member;

6: Chuck table;

60: supporting part;

61: ring frame holding part;

62: a wafer holding portion in a circular shape;

7: The laser light irradiates the component;

72: Concentrator;

8: Camera component;

9: with expansion device;

91: frame holding member;

92: with expansion member;

93: pick up the chuck;

10: chip;

11: ring frame;

12: Cutting tape.

detailed description

Next, preferred embodiments of the laser processing method and laser processing apparatus of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a perspective view of a laser processing device designed according to the invention.

A laser processing apparatus 1 shown in FIG. 1 includes a stationary base 2 , a first movable base 3 , a second movable base 4 , and a third movable base 5 . A pair of guide rails 21 , 21 extending in parallel in a direction indicated by an arrow Y (Y-axis direction) is provided on a side surface on the near side of the stationary base 2 .

The first movable base 3 is attached to the stationary base 2 so as to be slidable along the pair of guide rails 21 , 21 . That is, as shown in FIG. 1, a pair of guided grooves 31, 31 is provided on one surface of the first movable base 3 opposite to the stationary base 2. A pair of guide rails 21, 21 of the base 2 are fitted, and by fitting the pair of guided grooves 31, 31 with the pair of guide rails 21, 21, the first movable base 3 is assembled so that it can be mounted on the stationary base. 2 slides in the Y-axis direction along a pair of guide rails 21, 21. Further, on the other surface of the first movable base 3, a pair of guide rails 32, 32 extending in parallel in the direction indicated by the arrow Z (Z-axis direction) are provided. The laser processing apparatus in the illustrated embodiment includes a first moving member 30 for moving the first movable base 3 along the pair of guide rails 21 and 21 provided on the above-mentioned stationary base 2 . Move in the Y-axis direction. The first moving member 30 includes: an externally threaded rod 301 arranged between a pair of guide rails 21, 21 and parallel to the pair of guide rails 21, 21; and a pulse motor 302, which is used to drive the externally threaded rod 301 rotate. The external thread rod 301 is screwed to the internal thread 33 provided on the first movable base 3 , and one end of the external thread rod 301 is rotatably supported by a bearing member 303 provided on the stationary base 2 . The drive shaft of the pulse motor 302 is connected with the other end of the externally threaded rod 301 . Therefore, by driving the pulse motor 302 to rotate forward or reversely, the externally threaded rod 301 is driven forwardly or reversely, so that the first movable base 3 moves along the pair of guide rails 21 and 21 provided on the stationary base 2 in Y move in the axis direction.

The second movable base 4 is attached to the above-mentioned first movable base 3 so as to be slidable along the pair of guide rails 32 and 32 . That is, a pair of guided grooves 41, 41 is provided on one side surface of the second movable base 4 opposite to the first movable base 3, and the pair of guided grooves 41, 41 are slidably connected to the set. The pair of guide rails 32, 32 of the first movable base 3 are fitted, and the pair of guided grooves 41, 41 are fitted with the pair of guide rails 32, 32, so that the second movable base 4 is mounted. The first movable base 3 can slide along the pair of guide rails 32 and 32 in the direction indicated by the arrow Z (Z-axis direction). Moreover, the second movable base 4 is equipped with a pair of guide rails 42, 42, which are provided on the side surface perpendicular to the above-mentioned one side surface, and the pair of guide rails 42, 42 are arranged along the direction shown by the arrow X ( X-axis direction) extends in parallel. The laser processing apparatus in the illustrated embodiment includes a focal point position adjustment member 40 for moving the second movable base 4 along the first movable base 3 provided above. A pair of guide rails 32, 32 move in the Z-axis direction. The focusing point position adjustment member 40 includes: an externally threaded rod 401 arranged between a pair of guide rails 32, 32 and parallel to the pair of guide rails 32, 32; and a pulse motor 402, which is used to drive the externally threaded rod 401. The lever 401 rotates. The externally threaded rod 401 is screwed to the internal thread 43 provided on the above-mentioned second movable base 4, and one end of the externally threaded rod 401 is rotatably supported by a bearing member 403 provided on the first movable base 3. . The drive shaft of the pulse motor 402 is connected with the other end of the externally threaded rod 401 . Therefore, by driving the pulse motor 402 to rotate forward or reversely, the externally threaded rod 401 is driven forwardly or reversely, so that the second movable base 4 moves along the pair of guide rails 32, 32 moves in the Z-axis direction.

The third movable base 5 is attached to the above-mentioned second movable base 4 so as to be slidable along the pair of guide rails 42 and 42 . That is, a pair of guided grooves 51, 51 (only one on the upper side is shown in FIG. The pair of guided grooves 51, 51 are slidably engaged with the pair of guide rails 42, 42 provided on the second movable base 4, and the pair of guided grooves 51, 51 and the pair of guide rails 42 and 42 are fitted together, and the third movable base 5 is mounted on the second movable base 4 so as to be slidable in the direction indicated by the arrow X (X-axis direction) along the pair of guide rails 42 and 42 . The laser processing apparatus 1 in the illustrated embodiment is provided with a second moving member 50 for moving the third movable base 5 along a pair of the second movable base 4 described above. The guide rails 42, 42 move in the X-axis direction. The second moving member 50 includes: an externally threaded rod 501 arranged between a pair of guide rails 42, 42 and parallel to the pair of guide rails 42, 42; and a pulse motor 502, which is used to drive the externally threaded rod 501 to rotate . The externally threaded rod 501 is screwed to the internal thread (not shown) provided on the third movable base 5, and one end of the externally threaded rod 501 is supported by the bearing member 503 provided on the second movable base 4. to be able to rotate. The drive shaft of the pulse motor 502 is connected with the other end of the externally threaded rod 501 . Therefore, by driving the pulse motor 502 to rotate forward or reversely, the externally threaded rod 501 is driven forwardly or reversely, so that the third movable base 5 moves along the pair of guide rails 42, 42 moves in the X-axis direction.

On the other surface of the above-mentioned 3rd movable base 5, a chuck table 6 is installed via a support member 60. The wafer is held. The chuck table 6 is composed of an annular frame holding part 61 for holding a ring frame described later; The cutting belt installed on the ring frame described later. The frame holding part 61 is formed in a hollow shape by a metal member, and a plurality of suction holes 612 are opened on the upper surface, that is, the frame holding surface 611 . In the frame holding portion 61 formed in this way, the plurality of suction holes 612 communicate with a suction member (not shown) through the hollow portion. In addition, two positioning pins 613a and 613b for positioning an annular frame described later are erected on the frame holding surface 611 of the frame holding portion 61 . The wafer holding portion 62 is formed of a transparent member such as a glass plate, and its outer peripheral surface is attached to the inner peripheral wall of the annular frame holding portion 61 with a suitable adhesive. The wafer holding portion 62 configured in this way holds a wafer attached to a dicing tape attached to a ring frame to be described later on the wafer holding surface 621 , which is the upper surface.

The laser processing apparatus 1 shown in FIG. 1 includes a laser beam irradiation unit 7 for irradiating a laser beam as a workpiece held on the chuck table 6 as a workpiece. The laser beam irradiation member 7 includes: a housing 71; a laser beam oscillating member (not shown) such as a YAG laser oscillator or a YVO4 laser oscillator disposed in the housing 71; On the upper surface of one end of the housing 71 , the pulsed laser beam oscillated by the laser beam oscillating member is focused and irradiated upward.

On the upper side of the laser beam irradiation member 7 , an imaging member 8 for detecting a processing area to be laser processed by the laser beam irradiation member 7 is arranged. The camera component 8 includes components such as an illumination component, an optical system, and a camera device (CCD), and the image signal captured by the camera component 8 is sent to a control component not shown in the figure, and the illumination component is used for performing an inspection on the workpiece. In the illumination, the optical system is used to capture the area illuminated by the lighting member, and the imaging element is used to capture the image captured by the optical system. In the illustrated embodiment, the imaging member 8 is disposed directly above the condenser 72 at a predetermined interval. In addition, the imaging member 8 is mounted on an L-shaped bracket 80 mounted on the housing 71 of the laser beam irradiation member 7, and the chuck table 6 is configured to be able to be mounted on the condenser. 72 moves between the camera member 8.

The laser processing apparatus 1 in the illustrated embodiment is configured as described above, and its operation will be described below.

FIG. 2 shows a perspective view of a wafer processed by the laser processing method of the wafer according to the present invention. The wafer 10 shown in FIG. 2 is composed of a silicon wafer with a thickness of, for example, 400 μm. The surface 10 a of the wafer 10 is divided into a plurality of regions by a plurality of spaced roads 101 formed in a grid pattern, and formed in the divided regions. There is a Micro Electro Mechanical System (MEMS) as the device 102 .

In the wafer laser processing method of the present invention, first, as shown in FIG. 3 , the back surface 10 b of the wafer 10 is attached to the surface of the dicing tape 12 attached to the ring frame 11 (wafer supporting step). In addition, in the wafer supporting step, when the dicing tape 12 is attached to the ring frame 11, the back surface 10b of the wafer 10 may be attached to the front surface of the dicing tape 12 at the same time. Two engagement recesses 111a, 111b are provided on the outer peripheral end surface of the above-mentioned annular frame 11, and the two engagement recesses 111a, 111b are used to engage with two positioning pins 613a, 613b, and the two positioning pins 613a , 613b are erected on the frame holding surface 611 of the frame holding portion 61 of the chuck table 6 constituting the laser processing apparatus described above. Also, as the dicing tape 12, a polyvinyl chloride (PVC) or polyolefin (PO) sheet, for example, which transmits the laser beam irradiated by the laser beam irradiation member 7 of the above-mentioned laser processing device 1 is used.

4 to 6, the modified layer forming process is described. In the modified layer forming process, the above-mentioned laser processing device 1 is used to form a modified layer along the spacer 101 inside the wafer 10. The wafer 10 is shown in FIG. 3 is pasted on the surface of the cutting tape 12 mounted on the ring frame 11. To implement the altered layer forming step, first, as shown in FIG. 4 , the wafer 10 supported by the ring frame 11 via the dicing tape 12 is placed on the chuck table 6 of the laser processing apparatus 1 . At this time, the wafer 10 is placed on the wafer holding portion 62 through the dicing tape 12, and the ring frame 11 is placed on the ring frame holding portion 61 constituting the chuck table 6, and the ring frame 11 is placed on the ring frame. The two engaging recesses 111a and 111b of 11 engage with the two positioning pins 613a and 613b erected on the upper surface 611 of the frame holding part 61 . As a result, the wafer 10 supported by the ring frame 11 via the dicing tape 12 is positioned at a predetermined position on the chuck table 6 . Then, a suction member (not shown) is operated to suction-hold the ring frame 11 and the wafer 10 on the chuck table 6 via the dicing tape 12 (wafer holding step). Thus, the surface 10a of the wafer 10 held on the chuck table 6 is located on the upper side.

After performing the wafer holding process described above, the chuck table 6 holding the wafer 10 by suction is positioned directly under the imaging member 8 as shown in FIG. 5 by operating the first moving member 30 . After the chuck table 6 is positioned directly under the imaging member 8, a calibration process is performed. In this calibration process, the imaging unit 8 and the control unit not shown are used to detect the laser beam along the interval lane 101 of the wafer 10. Processing area for processing. That is, the imaging means 8 and the control means not shown in the figure perform image processing such as pattern matching, which is used to perform alignment of the spaced lanes 101 formed along a predetermined direction of the wafer 10, thereby completing the calibration of the laser beam irradiation position. Positional alignment between the light collectors 72 of the laser beam irradiation member 7 that irradiates laser beams along the partition lanes 101 . Also, the calibration of the irradiation position of the laser light is also performed for the plurality of streets 101 formed in a direction orthogonal to the plurality of streets 101 formed on the wafer 10 .

As described above, after detecting the spaced lanes 101 formed on the wafer 10 held on the chuck table 6 and performing calibration of the laser beam irradiation position, the chuck table is moved as shown in (a) of FIG. 6 . 6. Move to the laser beam irradiation area where the light collector 72 of the laser beam irradiation member 7 is located, and position one end (the left end in FIG. Just above the optical device 72. Then, the converging point P of the pulsed laser light is aligned at a lower position away from the surface 10 a (upper surface) of the wafer 10 , for example, by about 30 μm. Next, while irradiating pulsed laser light with a wavelength that is transparent to the silicon wafer from the concentrator 72, the chuck table 6 is moved at a predetermined speed along the direction indicated by the arrow X1 in (a) of FIG. 6 . Give speed to move. At this time, the pulsed laser light irradiated from the concentrator 72 passes through the wafer holder 62 formed of a transparent member such as a glass plate and the dicing tape 12 formed of polyvinyl chloride (PVC) or polyolefin (PO) The back surface 10b side of the wafer 10 is irradiated. Then, as shown in (b) of FIG. 6 , when the other end (right end in (b) of FIG. 6 ) of the interval road 101 reaches the irradiation position of the light collector 72 of the laser light irradiation member 7, the pulsed laser light is stopped. Light irradiation, and stop the movement of chuck table 6. As a result, an altered layer 110 is formed in the vicinity of the surface 10 a (upper surface) of the wafer 10 along the street 101 inside the wafer 10 . The degenerated layer 110 is formed as a melt-resolidified layer.

The processing conditions in the above-mentioned altered layer forming step are set as follows, for example.

In addition, under the above processing conditions, the thickness of the altered layer 110 formed by one irradiation of laser light is 50 μm to 60 μm. Therefore, in order to easily divide the wafer 10 having a thickness of 400 μm, it is necessary to form about five altered layers having a thickness of 50 μm to 60 μm. Therefore, by sequentially moving the converging point P of the pulsed laser beam irradiated from the concentrator 72 of the laser beam irradiating member 7 downward and performing the above-mentioned altered layer forming process, the wafer is formed as shown in (c) of FIG. 6 . The interior of 10 forms five metamorphic layers 110 along the spacer 101 . In addition, since in the altered layer forming process, the wafer holder 62 formed of a transparent member such as a glass plate and the dicing tape 12 composed of polyvinyl chloride (PVC) or polyolefin (PO) sheet are passed through from the back surface of the wafer 10, Since the pulsed laser light is irradiated on the side 10b, the pulsed laser light does not irradiate the device 102. This eliminates the need for a street having a width of 20% to 30% of the thickness of the wafer 10 , so there is no restriction on the width of the street in terms of wafer design. Moreover, since the back side of the wafer 10 is pasted on the dicing tape 12 from the beginning, it is not necessary to turn over the front and back of the wafer 10 and stick them again after the altered layer is formed. Problems such as rupture of the septal tract can be avoided in the first place.

In this way, after the altered layer forming step is performed along all the streets 101 extending in the predetermined direction of the wafer 10, the altered layer forming step is performed along the streets 101 formed in the direction perpendicular to the predetermined direction. That is, as shown in (a) of FIG. Just above the condenser 72. Then, the converging point P of the pulsed laser light is aligned at a lower position away from the surface 10 a (upper surface) of the wafer 10 , for example, by about 30 μm. Next, while irradiating pulsed laser light having a wavelength that is transparent to the silicon wafer from the concentrator 72, the chuck table 6 is advanced at a predetermined rate in the direction indicated by the arrow Y1 in (a) of FIG. Speed moves. At this time, the pulsed laser light irradiated from the concentrator 72 passes through the wafer holder 62 formed of a transparent member such as a glass plate and the dicing tape 12 formed of a polyvinyl chloride (PVC) or polyolefin (PO) sheet, from the wafer. 10 backside 10b side for irradiation. In this way, the above-described modified layer forming step is carried out along each of the partition streets 101 formed in a direction perpendicular to the predetermined direction.

After performing the modified layer forming step described above, a breaking step is performed in which an external force is applied to the wafer 10 to break the wafer 10 along the spacer lanes 101 where the modified layer 110 is formed. This breaking step is carried out using the tape expanding device 9 shown in FIG. 8 . The tape expansion device 9 shown in FIG. 8 is provided with: a frame holding member 91 for holding the above-mentioned annular frame 11; a tape expansion member 92 for expanding the cutting tape 12 mounted on and held on the the ring-shaped frame 11 of the frame holding member 91 ; and the pick-up chuck 93 . The frame holding member 91 is composed of an annular frame holding member 911 and a plurality of clips 912 as fixing members arranged on the outer periphery of the frame holding member 911 . The upper surface of the frame holding member 911 is formed as a placement surface 911a on which the ring frame 11 is placed, and the ring frame 11 is placed on the placement surface 911a. Furthermore, the ring-shaped frame 11 placed on the mounting surface 911 a is fixed to the frame holding member 911 by the clamp 912 . The frame holding member 91 configured in this way is supported by the belt expansion member 92 so as to be able to advance and retreat in the vertical direction.

The belt expansion member 92 includes an expansion cylinder 921 disposed inside the annular frame holding member 911 . The inner diameter and outer diameter of the expansion cylinder 921 are smaller than the inner diameter of the ring frame 11 and larger than the outer diameter of the wafer 10 attached to the dicing tape 12 attached to the ring frame 11 . Furthermore, the expansion cylinder 921 has a support flange 922 at the lower end. The belt expansion member 92 in the illustrated embodiment includes a support member 923 that enables the above-mentioned annular frame holding member 911 to advance and retreat in the vertical direction. The supporting member 923 is constituted by a plurality of cylinders 923 a disposed on the supporting flange 922 , and the piston rods 923 b of the plurality of cylinders 923 a are connected to the lower surface of the annular frame holding member 911 . Thus, the support member 923 constituted by a plurality of cylinders 923a moves the ring-shaped frame holding member 911 in the vertical direction between the reference position and the expanded position. As shown in FIG. 9( a), at the reference position, the The surface 911a is located at approximately the same height as the upper end of the expansion cylinder 921. As shown in FIG.

Referring to FIG. 9 , the wafer breaking step performed by the tape expanding device 9 configured as described above will be described. That is, as shown in (a) of FIG. 9 , the ring-shaped frame 11 on which the dicing tape 12 to which the wafer 10 is pasted is mounted on the mounting surface 911 a of the frame holding member 911 constituting the frame holding member 91 , and is used The clamp 912 fixes the ring frame 11 to the frame holding member 911 (frame holding step). At this time, the frame holding member 911 is positioned at the reference position shown in (a) of FIG. 9 .

As shown in FIG. 9( b ), after the above-mentioned frame holding step is performed, a plurality of cylinders 923a serving as support members 923 constituting the belt expansion member 92 are operated to lower the annular frame holding member 911 to the expanded position. Thereby, the annular frame 11 fixed on the mounting surface 911a of the frame holding member 911 also descends, and therefore, as shown in FIG. The upper edge of 921 contacts and expands (cutting band expanding process). As a result, a tensile force acts radially on the wafer 10 attached to the dicing tape 12 . In this way, when the tensile force radially acts on the wafer 10, the strength of the metamorphic layer 110 formed along the spacer 101 is reduced. Therefore, the metamorphic layer 110 with reduced strength becomes the origin of fracture, and the wafer 10 along the spacer 101 disconnected, thereby being divided into individual devices 102 .

As shown in FIG. 10, after the wafer 10 is divided into individual devices 102 by performing the above-mentioned wafer breaking process along the spacer 101 formed with the altered layer 110, the pickup chuck 93 is operated to extract the wafer 10. The device 102 is sucked so that the device 102 is peeled off from the dicing tape 12 and picked up (pick-up process). In addition, in the pick-up process, since the gap S between individual devices 102 is already enlarged, pick-up can be easily performed without contacting adjacent devices 102 .

As mentioned above, although this invention was demonstrated based on illustrated embodiment, this invention is not limited only to embodiment, Various deformation|transformation is possible within the range of the summary of this invention. For example, in the above-mentioned embodiment, an example in which a wafer formed with devices composed of microelectromechanical systems (MEMS) is divided into individual devices is shown, but the present invention can also be applied to devices formed with ICs, LSIs, etc. Semiconductor wafers or optical device wafers formed with light-emitting diodes, CCDs and other optical devices.

Claims (1)

1. A laser processing device, the laser processing device is used to irradiate laser light to the inside of the wafer along the interval road to form a metamorphic layer along the interval road inside the wafer, and the wafer is formed in a lattice shape on the surface a plurality of spaced lanes, and the wafer is formed with devices in a plurality of regions divided by the plurality of spaced lanes, The laser processing device is characterized in that, The laser processing apparatus includes: a chuck table having a wafer holding portion and an annular frame holding portion for performing processing on a wafer attached to a dicing tape attached to the ring frame. holding, the ring-shaped frame holding part is provided on the outer side of the wafer holding part in the outer peripheral direction, and has a frame holding surface for holding the ring-shaped frame; the condenser for irradiating laser light having a wavelength that is transparent to the wafer held on the chuck table and the dicing tape; and a moving member for making the chuck table and the dicing tape The concentrator moves relatively, The wafer holding portion of the chuck table is formed of a transparent member, A plurality of suction holes for sucking the ring frame through the cutting tape are formed on the frame holding surface of the ring frame holding part of the chuck table, and the ring frame a plurality of suction holes for suction holding the dicing band in the area between the frame and the outer periphery of the wafer, The concentrator of the laser light irradiating means is configured to irradiate the wafer with laser light from the lower side of the wafer holding part of the chuck table through the wafer holding part and the dicing tape.