JP6091335B2 - Dividing method and dividing apparatus - Google Patents

Description

  The present invention relates to a dividing method and a dividing apparatus for dividing a plate-like object such as a wafer.

  In order to divide a wafer into a plurality of chips, there has been proposed a dividing method in which a modified layer serving as a starting point of dividing is formed along the street (division planned line) of the wafer, and stress is applied to the wafer along this street. (For example, refer to Patent Document 1).

  In the dividing method of Patent Document 1, first, a wafer on which a modified layer is formed along a street is fixed to a dividing apparatus including a movable suction unit. The suction means includes a linear suction part and can suck the wafer along the street. Further, the wafer is fixed to the dividing device via a sheet attached to the front surface or the back surface.

  Thereafter, the suction unit moves the suction unit from the start point corresponding to the outer peripheral edge of the wafer toward the opposite end point across the center of the wafer, and the suction unit sucks the wafer. The wafer is sucked along the street from the sheet side and divided into chips.

JP 2006-108273 A

  By the way, the central part of the sheet adhered to the wafer is not fixed to the dividing device, and is easier to bend because it is farthest from the fixing means for fixing the sheet to the dividing device as compared with other regions of the wafer. ing. Therefore, when the suction means moved from the starting point side of the outer peripheral edge reaches the vicinity of the center of the wafer and the divided area of the wafer becomes wider, the deflection of the central portion of the sheet increases.

  When the deflection of the central portion of the sheet increases, stress in a direction inclined with respect to the front or back surface of the wafer (for example, stress in the moving direction of the suction means) is generated, which is called oblique cracking in which the wafer is divided on the inclined surface. The phenomenon will occur.

  This invention is made | formed in view of this point, The place made into the objective is providing the division | segmentation method and the division | segmentation apparatus which suppressed the possibility of the diagonal crack low.

According to the present invention, the division starting point is formed along the planned division line, and the division device is provided with a division bar that applies an external force to the circular plate attached to the sheet by suction. A sheet splitting method along a line, in which a split starting point is formed along a planned split line and the sheet on the outer peripheral side of a circular plate attached on the sheet is fixed to the splitting device A fixing step, a positioning step of positioning the dividing bar in the center of the circular plate and the positioning direction of the dividing bar in parallel with the extending direction of the division line of the circular plate, After performing the sheet fixing step and the positioning step, the circular plate-like object is sucked by the dividing bar through the sheet, and in a direction orthogonal to the extending direction of the division line to be divided. A first dividing step in which the dividing bar is moved from the center of the circular plate toward the outer peripheral edge at one end, and the circular plate is divided along the division line in an area corresponding to half of the circular plate, After carrying out the first dividing step, the circular bar is moved from the center of the circular plate toward the outer peripheral edge of the circular plate by sucking the circular plate with the dividing bar through the sheet. A second dividing step of dividing the circular plate-like object by the division line in the region corresponding to the remaining half of the plate-like object, and in the first dividing step and the second dividing step, the dividing bar is There is provided a dividing method characterized in that bending of the sheet is suppressed by moving from the center of the sheet toward an area outside the sheet fixed to the dividing device .

  The central portion of the sheet adhered to the circular plate is not fixed to the dividing device, and is more flexible than the other area of the wafer because it is farthest from the fixing means for fixing the sheet to the dividing device. . Therefore, when the circular plate is divided by moving the dividing bar from the one end side to the other end side of the outer peripheral edge, an oblique crack in which the circular plate is divided on the inclined surface is likely to occur.

  On the other hand, in the present invention, since the dividing bar is moved from the center of the circular plate-shaped object to the outer peripheral edge so as to go to the area outside the sheet fixed to the dividing device, even if the division proceeds, the sheet Can be suppressed. Thereby, the possibility of the diagonal crack of a circular plate-shaped object can be suppressed low.

It is a perspective view which shows typically the wafer divided | segmented with the division | segmentation method which concerns on this Embodiment. It is a perspective view which shows typically the structural example of the division | segmentation apparatus which concerns on this Embodiment. It is a perspective view showing typically an example of composition of a division bar (suction means), a movement mechanism (movement means), and a rotation mechanism (rotation means) with which a division device concerning this embodiment is provided. It is a figure which shows typically the periphery structure of the division | segmentation bar with which the division | segmentation apparatus which concerns on this Embodiment is provided. It is a top view which shows typically the positioning step and 1st division | segmentation step which concern on this Embodiment. It is a top view which shows typically the 2nd division | segmentation step which concerns on this Embodiment. It is a top view which shows typically the 3rd division | segmentation step which concerns on this Embodiment. It is a top view which shows typically the 4th division | segmentation step which concerns on this Embodiment.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a wafer to be divided by the dividing method according to the present embodiment. As shown in FIG. 1, a wafer (circular plate-like object) 11 to be divided is, for example, a semiconductor wafer having a disk-like outer shape, and a central device region 13 and an outer peripheral surplus region surrounding the device region 13. 15.

  The device region 13 on the surface 11a side of the wafer 11 is partitioned into a plurality of regions by streets (division planned lines) 17 arranged in a lattice pattern, and a device 19 such as an IC is formed in each region.

  Inside the wafer 11, a modified layer (division starting point) 21 is formed along each street 17 as a starting point of division. The modified layer 21 is formed, for example, by condensing a laser beam having a wavelength that is difficult to be absorbed by the wafer 11 inside the wafer 11.

  A sheet 23 made of a material such as a resin is attached to the back surface 11 b side of the wafer 11. The sheet 23 is fixed to an annular frame 25 in a region outside the outer peripheral edge of the wafer 11.

  That is, the wafer 11 is held on the frame 25 via the sheet 23. Although FIG. 1 shows an aspect in which the sheet 23 is attached to the back surface 11 b side of the wafer 11, the sheet 23 may be attached to the front surface 11 a side of the wafer 11. Further, the seat 23 is not necessarily fixed to the frame 25.

  FIG. 2 is a perspective view schematically showing a configuration example of a dividing device used in the dividing method according to the present embodiment. FIG. 3 is a diagram illustrating a dividing bar (suction means) and a moving mechanism (moving) provided in the dividing device. 2 is a perspective view schematically showing a configuration example of a rotation mechanism (rotation means).

  As shown in FIG. 2, the dividing device 2 includes a rectangular parallelepiped housing 4. An annular base 6 having an opening (not shown) is provided on the upper surface of the housing 4, and a cylindrical drum 8 is disposed in the opening of the base 6.

  For example, the outer diameter of the drum 8 is smaller than the inner diameter of the frame 25, and the inner diameter of the drum 8 is larger than the outer diameter of the wafer 11. However, the drum 8 may be omitted.

  Four elevating mechanisms 10 are provided on the upper surface of the base 6 so as to surround the outer periphery of the drum 8. Each lifting mechanism 10 includes a cylinder case 12 and a piston rod 14, and an annular table 16 is fixed to the upper end portion of the piston rod 14. The height position of the table 16 is adjusted by the lifting mechanism 10.

  The upper surface of the table 16 is a mounting surface 16a on which the frame 25 is mounted. The drum 8 is disposed in the circular opening 16b of the table 16, and four clamps (fixing means) are provided around the table 16 to sandwich and fix the frame 25 mounted on the mounting surface 16a from four directions. ) 18 is provided.

  The frame 25 is placed on the placement surface 16 a of the table 16 so that the wafer 11 is disposed above the sheet 23. That is, the wafer 11 is positioned in the vicinity of the center of the opening 16b so that the back surface 11a side faces downward. However, the arrangement of the wafer 11 and the like is not limited to this.

  A split bar (suction means) 20 for sucking the wafer 11 held on the table 16 is provided inside the drum 8. Above the dividing bar 20, a microscope (imaging means) 22 that images the wafer 11 held on the table 16 is arranged.

  As shown in FIG. 3, the division | segmentation bar 20 is formed in the plate shape which has predetermined | prescribed thickness, and has the upper surface 20a containing the inclined surface with respect to a horizontal direction. The longitudinal direction of the upper surface 20 a is longer than the street 17 of the wafer 11. A part of the upper surface 20 a comes into contact with the back surface 11 b of the wafer 11 through the sheet 23.

  FIG. 4 is a diagram schematically showing the peripheral structure of the dividing bar. A linear suction part 20 b is formed on the upper surface 20 a of the dividing bar 20, and the suction part 20 b is connected to a suction source 28 via a suction path 24 and a valve 26.

  That is, one end side of the suction path 24 is connected to the suction part 20 b, and the other end side of the suction path 24 is connected to the suction source 28. The negative pressure of the suction source 28 acts on the suction unit 20b, so that the wafer 11 is sucked downward through the sheet 23.

  As shown in FIG. 3, a moving mechanism (moving means) 30 that moves the dividing bar 20 in a direction parallel to the mounting surface 16 a of the table 16 (horizontal direction) is provided below the dividing bar 20. Yes. The moving mechanism 30 is disposed in a space formed inside the housing 4.

  The moving mechanism 30 includes a first moving mechanism 34 that moves the first moving table 32 in a first direction parallel to the placement surface 16 a of the table 16. The first moving mechanism 34 includes a pair of first guide rails 36 parallel to the first direction, and the first moving table 32 is slidably installed on the first guide rail 36.

  A nut (not shown) is fixed to the lower surface side of the first moving table 32, and a first ball screw 38 parallel to the first guide rail 36 is screwed to the nut. A first pulse motor 40 is connected to one end side of the first ball screw 38. The first moving table 32 moves in the first direction along the first guide rail 36 by rotating the first ball screw 38 by the first pulse motor 40.

  On the first moving table 32, a second moving mechanism 44 for moving the second moving table 42 in a second direction parallel to the placement surface 16a of the table 16 and perpendicular to the first direction is provided. Yes. The second moving mechanism 44 includes a pair of second guide rails 46 parallel to the second direction, and the second moving table 42 is slidably installed on the second guide rails 46.

  A nut (not shown) is fixed to the lower surface side of the second moving table 42, and a second ball screw 48 parallel to the second guide rail 46 is screwed to the nut. A second pulse motor 50 is connected to one end side of the second ball screw 48. The second moving table 42 moves in the second direction along the second guide rail 46 by rotating the second ball screw 48 by the second pulse motor 50.

  A rotating mechanism (rotating means) 52 such as a motor is provided on the second moving table 42. The rotating mechanism 52 includes a rotating shaft 54 that is perpendicular to the mounting surface 16 a of the table 16, and is connected to the dividing bar 20 via the rotating shaft 54.

  The split bar 20 rotates around the rotation axis 54 perpendicular to the mounting surface 16 a of the table 16 by the rotational force transmitted from the rotation mechanism 52. The rotating mechanism 52 is configured to be able to rotate the rotating shaft 54 at least 180 degrees (180 degrees or more). That is, the dividing bar 20 is rotated at least 180 degrees in the horizontal direction.

  In dividing the wafer 11, the dividing bar 20 is rotated by the rotating mechanism 52 to align the suction portion 20 b with the target street 17, and then the dividing bar 20 is moved in a direction orthogonal to the dividing target street 17 by the moving mechanism 24. Move. As shown in FIG. 4, the wafer 11 is divided along the street 17 by moving the dividing bar 20 and applying a downward suction force from the suction portion 20 b.

  Next, details of the dividing method according to the present embodiment will be described. The dividing method according to the present embodiment includes a sheet fixing step, a positioning step, a first dividing step, and a second dividing step. FIG. 5 is a plan view schematically showing the positioning step and the first division step, and FIG. 6 is a plan view schematically showing the second division step.

  In the sheet fixing step, the frame 25 holding the wafer 11 via the sheet 23 is placed on the table 16 of the dividing apparatus 2 and clamped and fixed by the four clamps 18. In the present embodiment, the frame 25 is placed so that the back surface 11a side of the wafer 11 faces downward, but the present invention is not limited to this.

  As a result, the area outside the sheet 23 is fixed to the dividing device 2 via the frame 25. If the sheet 23 is not fixed to the frame 25, the area outside the sheet 23 may be directly fixed to the table 16. That is, in the sheet fixing step, it is sufficient that at least the area outside the sheet 23 can be fixed to the dividing device 2.

  A positioning step is performed after the sheet fixing step. In the positioning step, the division bar 20 is rotated by the rotation mechanism 52 so that the longitudinal direction (extension direction) of the upper surface 20a of the division bar 20 and the street 17 to be divided (extension direction of the street 17) are parallel to each other.

  Then, as shown in FIG. 5A, the dividing bar 20 is moved in the horizontal direction by the moving mechanism 24 and positioned near the center of the wafer 11. In this positioning step, the valve 26 provided in the suction path 24 is closed so that the wafer 11 is not sucked by the dividing bar 20.

  In this embodiment, the positioning step is performed after the sheet fixing step. However, the positioning step may be performed first. Of course, the sheet fixing step and the positioning step may be performed at the same timing.

  After the sheet fixing step and the positioning step, the first division step is performed. In the first division step, as shown in FIG. 5B, the wafer 11 is sucked by opening the valve 26 while moving the division bar 20 from the vicinity of the center of the wafer 11 toward the one end E1 side of the outer periphery. The moving direction of the dividing bar 20 is a direction A1 orthogonal to the dividing target street 17.

  The wafer 11 is sucked through the sheet 23 by the moving dividing bar 20. Since the dividing bar 20 is aligned so that the longitudinal direction of the upper surface 20a and the street 17 to be divided are parallel, a downward suction force along the dividing street 17 acts on the wafer 11. . As a result, the wafer 11 is divided along the street 17 to be divided. In this first dividing step, an approximately half area of the wafer 11 corresponding to the path of the dividing bar 20 is divided.

  After the first division step, the second division step is performed. In the second dividing step, first, as shown in FIG. 6A, the dividing bar 20 is moved and positioned near the center of the wafer 11, and the dividing bar 20 is rotated 180 degrees. At this time, the valve 26 provided in the suction path 24 is closed so that the wafer 11 is not sucked by the dividing bar 20.

  Then, as shown in FIG. 6B, the wafer 26 is sucked by opening the valve 26 while moving the dividing bar 20 from the vicinity of the center of the wafer 11 toward the other end E2 side of the outer periphery. The moving direction of the dividing bar 20 is set to a direction A2 orthogonal to the dividing target street 17.

  Accordingly, the wafer 11 is sucked through the sheet 23 by the moving dividing bar 20. As a result, the wafer 11 is divided along the street 17 to be divided. In this second dividing step, the remaining half of the area of the wafer 11 corresponding to the path of the dividing bar 20 is divided.

  After performing the second dividing step, the wafer 11 is divided on the street 17 orthogonal to the street 17 targeted in the first dividing step and the second dividing step. FIG. 7 is a plan view schematically showing the third division step, and FIG. 8 is a plan view schematically showing the fourth division step.

  In the third division step, first, as shown in FIG. 7A, the division bar 20 is moved and positioned near the center of the wafer 11, and the division bar 20 is rotated by 90 degrees. Thereby, the longitudinal direction of the upper surface 20a of the dividing bar 20 is positioned in parallel to the street 17 to be divided. The valve 26 provided in the suction path 24 is closed.

  Then, as shown in FIG. 7B, while the dividing bar 20 is moved from the vicinity of the center of the wafer 11 toward the one end E3 side of the outer periphery, the valve 26 is opened and the wafer 11 is sucked. The moving direction of the dividing bar 20 is a direction A3 orthogonal to the target street 17.

  Accordingly, the wafer 11 is sucked through the sheet 23 by the moving dividing bar 20. As a result, the wafer 11 is divided along the street 17 to be divided. In this third division step, an approximately half region of the wafer 11 corresponding to the path of the division bar 20 is divided.

  After the third division step, the fourth division step is performed. In the fourth division step, first, as shown in FIG. 8A, the division bar 20 is moved and positioned near the center of the wafer 11, and the division bar 20 is rotated 180 degrees. The valve 26 provided in the suction path 24 is closed.

  Then, as shown in FIG. 8B, while the dividing bar 20 is moved from the vicinity of the center of the wafer 11 toward the other end E4 side of the outer periphery, the valve 26 is opened and the wafer 11 is sucked. The moving direction of the dividing bar 20 is a direction A4 orthogonal to the dividing target street 17.

  Accordingly, the wafer 11 is sucked through the sheet 23 by the moving dividing bar 20. As a result, the wafer 11 is divided along the street 17 to be divided. In this fourth division step, the remaining half of the area of the wafer 11 corresponding to the path of the division bar 20 is divided. The wafer 11 is divided into a plurality of chips corresponding to each device 19 by the first division step to the fourth division step described above.

  As described above, in the present invention, the dividing bar 20 is moved from the center of the wafer (circular plate-like object) 11 to the outer peripheral edge so as to go to the region outside the sheet 23 fixed to the dividing device 2.

  Therefore, the moving distance by the dividing bar 20 is halved compared to the conventional case, and the amount of bending of the sheet 23 is also halved. Moreover, since the division | segmentation bar | burr 20 is moved toward the direction of the outer periphery fixed with the clamp (fixing means) 18 from the center of the sheet | seat 23 which is easy to bend, the bending of the sheet | seat 23 can be suppressed. Thus, according to the present invention, even if the division proceeds, the bending of the sheet 23 can be suppressed, and the possibility of the oblique cracking of the wafer 11 can be suppressed low.

  Further, since the dividing apparatus 2 of the present invention employs a configuration in which the dividing bar 20 is rotated with respect to the wafer 11, a large rotating mechanism for rotating the table 16 is necessary as in the case of rotating the wafer 11. Absent. Therefore, the dividing device 2 can be reduced in size.

  In addition, this invention is not limited to description of the said embodiment, A various change can be implemented. For example, in the above embodiment, as shown in FIGS. 6 to 8, the dividing bar 20 is rotated in one direction (clockwise toward FIGS. 6 to 8), but the rotating direction of the dividing bar 20 is It is not limited to this.

  Moreover, in the said embodiment, although the 3rd division step and the 4th division step are implemented in addition to the 1st division step and the 2nd division step, the 3rd division step and the 4th division step are omitted. May be.

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

2 Splitting device 4 Housing 6 Base 8 Drum 10 Elevating mechanism 12 Cylinder case 14 Piston rod 16 Table 16a Mounting surface 16b Opening 18 Clamp (fixing means)
20 dividing bar 20a upper surface 20b suction part 22 microscope 24 suction path 26 valve 28 suction source 30 moving mechanism (moving means)
32 1st moving table 34 1st moving mechanism 36 1st guide rail 38 1st ball screw 40 1st pulse motor 42 2nd moving table 44 2nd moving mechanism 46 2nd guide rail 48 2nd ball screw 50 2nd pulse motor 52 rotation Mechanism (rotating means)
54 Rotating shaft 11 Wafer (Circular plate)
11a Front surface 11b Back surface 13 Device region 15 Peripheral surplus region 17 Street (division planned line)
19 Device 21 Modified layer (division starting point)
23 seats 25 frames

Claims (1)

A division starting point is formed along the planned division line, and the division device is provided with a division bar that applies an external force to the circular plate-like object stuck on the sheet by suction, and is divided along the planned division line. A division method,
A sheet fixing step for fixing the sheet on the outer peripheral side of the circular plate attached to the sheet and forming the dividing start point along the planned dividing line to the dividing device ;
A positioning step for positioning the extending direction of the dividing bar and the extending direction of the planned dividing line of the circular plate in parallel and positioning the dividing bar in the center of the circular plate through the sheet;
After performing the sheet fixing step and the positioning step, the partition bar is moved in a direction orthogonal to the extending direction of the division line to be divided while sucking the circular plate-like object with the division bar through the sheet. A first dividing step of moving the circular plate-like object from the center of the circular plate-like object toward the outer peripheral edge at one end, and dividing the circular plate-like object along the planned dividing line in a region corresponding to half of the circular plate-like object;
After carrying out the first dividing step, the dividing bar is moved from the center of the circular plate toward the outer peripheral edge of the other end while sucking the circular plate with the dividing bar through the sheet, A second dividing step of dividing the circular plate-like object at the division line of the region corresponding to the remaining half of the circular plate-like object ,
In the first dividing step and the second dividing step, the bending of the sheet is suppressed by moving the dividing bar from the center of the sheet toward an area outside the sheet fixed to the dividing device. A dividing method characterized by

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