JP5939792B2 - Sapphire substrate - Google Patents

Description

  The present invention relates to a sapphire substrate that is ground by a grinding apparatus.

  The sapphire substrate on which the optical device such as LED is partitioned and formed on the surface by the grid-like division lines is formed on the surface with the back surface ground to a predetermined thickness, and then divided by, for example, a laser processing apparatus The line is irradiated with a laser beam, divided into individual optical devices, and incorporated into various electric devices such as lighting devices, liquid crystal televisions, and mobile phones.

  The grinding apparatus includes: a chuck table that holds a workpiece; a grinding unit that rotatably rotates a grinding wheel that grinds the workpiece held on the chuck table; and a grinding feed unit that feeds the grinding unit by grinding. At least, the sapphire substrate can be ground to a predetermined thickness with high accuracy by bringing the grinding wheel provided in the grinding wheel into contact with the rotating sapphire substrate and pressing it with the grinding feed means (for example, the following) Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-40631

  However, the sapphire substrate has a chamfered portion formed by chamfering a corner formed by one surface and the other surface and side surfaces. For example, a sapphire substrate having a thickness of 1300 μm has an inclination of 45 degrees. Since a chamfered portion having a height of about 130 μm is formed, when one surface of the sapphire substrate is ground, the total thickness is reduced to 180 μm due to the formation of the chamfered portion. There is a problem that fine chips are generated on the outer periphery of the sapphire substrate and the quality of the optical device located on the outer peripheral side of the sapphire substrate is deteriorated. In addition, there is a problem that a crack is generated in the sapphire substrate due to the chipping generated on the outer periphery of the sapphire substrate, thereby damaging the optical device.

  The present invention has been made in view of the above circumstances, and there is a problem to be solved by enabling a sapphire substrate to be thinly ground so as to have a thickness of 180 μm or less without causing chipping in the outer periphery. is there.

The present invention, have a ring-shaped side leading to the outer periphery of the other surface from the outer peripheral edge of one surface of the sapphire substrate, a sapphire substrate before the other surface is ground, one of the sapphire substrate chamfered portion corners formed by the surface and the side surface and the corner portion formed by the other side and the side of the formation, the chamfered portion, the one surface and the other surface in the thickness direction with respect is formed in a height of less than 50 [mu] m, is formed to be inclined at an angle of less than 45 degrees 90 degrees with respect to said one surface and said other surface on the outer peripheral side, on one surface of the sapphire substrate The light emitting layer is laminated, the chamfered portion is formed on the basis of the one surface, and the other surface is ground to a thickness of 100 to 120 μm.

  The chamfered portion is preferably formed to be inclined at an angle of 50 degrees or more and 80 degrees or less with respect to one surface or the other surface.

  In the present invention, a chamfered portion is formed at a corner formed by one surface of the sapphire substrate or the other surface and the side surface, and the chamfered portion is 50 μm or less in the thickness direction with respect to one surface or the other surface. And is inclined at an angle of 45 degrees or more and less than 90 degrees with respect to one surface or the other surface, and the inclination angle with respect to one surface or the other surface is larger than the conventional one. Therefore, the durability of the sapphire substrate against the pressing force at the time of grinding with the grindstone is improved, and the thickness of the sapphire substrate can be ground to a thickness of 180 μm or less without generating a chip on the outer periphery of the sapphire substrate.

  In addition, when the chamfered portion is inclined at an angle of 50 degrees or more and 80 degrees or less with respect to one surface or the other surface, chipping occurs in the outer periphery of the sapphire substrate with the function of the chamfered portion. It can prevent more reliably.

It is a perspective view which shows an example of a grinding device. (A) is a perspective view which shows the upper surface side of the sapphire substrate in which the light emitting layer was formed. (B) is the fragmentary sectional view of the sapphire substrate in which the light emitting layer was formed and the corner | angular part was formed. (C) is a fragmentary sectional view of the sapphire substrate in which the light emitting layer was formed and the chamfered part was formed. It is a fragmentary sectional view of the sapphire substrate in which the chamfered portion is formed and the light emitting layer is not laminated on the upper surface. It is a perspective view which shows the state which affixes the upper surface side of a sapphire substrate to the protective tape united with the flame | frame. It is a perspective view which shows the state which hold | maintains to the chuck table the sapphire board | substrate supported by the flame | frame via a protective tape. It is sectional drawing which shows the state which sucked and held the sapphire substrate to the chuck table. It is a perspective view which shows the state which grinds the lower surface of a sapphire substrate.

  A grinding apparatus 1 shown in FIG. 1 is a grinding apparatus for grinding the sapphire substrate 5 shown in FIG. 2 and the sapphire substrate 5a shown in FIG. First, the apparatus configuration of the grinding apparatus 1 will be described.

  As shown in FIG. 1, the grinding device 1 is composed of a device base 2a extending in the Y-axis direction and a standing base 2b extending in the Z-axis direction at the rear of the device base 2a, and the front side of the standing base 2b. Are provided with a grinding means 20 and a grinding feed means 30 for grinding and feeding the grinding means 20 in the Z-axis direction. A telescopic bellows 3 is disposed on the upper surface of the apparatus base 2 a, and a rotatable chuck table 10 is disposed on the bellows 3 via a movable base 4.

  The grinding means 20 includes a spindle 21 having an axis in the Z-axis direction, a spindle housing 22 that rotatably supports the spindle 21, a holding portion 23 that holds the outer periphery of the spindle housing 22, and a motor 24 that rotates the spindle 21. And. A mounter 25 is mounted at the lower end of the spindle 21, and a grinding wheel 26 is fixed by a bolt 27 at the lower end of the mounter 25. A plurality of grindstones 28 are fixed to the lower portion of the grinding wheel 26. The grinding means 20 can rotate the grinding wheel 26 at a predetermined rotational speed by the motor 24 rotating the spindle 21.

  The grinding feed means 30 includes a ball screw 31 extending in the Z-axis direction, a motor 32 attached to the upper end of the ball screw 31, a pair of guide rails 33 arranged in parallel to the ball screw 31, and the grinding means 20. And a moving base 34 for grinding and feeding in the Z-axis direction. A holding portion 23 for holding the spindle housing 22 is fixed to one surface of the moving base 34, and a nut structure (not shown) is formed at the center of the other surface. Are screwed together. Then, when the ball screw 31 is rotated by driving the motor 32, the moving base 34 is guided by the guide rail 33, and the grinding feed means 20 can be moved in the Z-axis direction.

  A sapphire substrate 5 shown in FIG. 2 is a first example of a sapphire substrate according to the present invention. The sapphire substrate 5 shown in FIG. 2A is formed in a disc shape, and has one surface and the other surface located on the back surface side. In the following description, one surface in FIG. 2 is an upper surface 50 and the other surface is a lower surface 51.

  As shown in FIG. 2A, the sapphire substrate 5 has a ring-shaped side surface 52 that extends from the outer peripheral edge of the upper surface 50 to the outer peripheral edge of the lower surface 51. On the upper surface 50 of the sapphire substrate 5, a plurality of optical devices 57 are formed in a region partitioned by a grid-like division planned line 56. Further, a notch 58 that is a mark indicating the crystal orientation of the substrate is formed on the side surface 52 of the sapphire substrate 5.

  As shown in FIG. 2B, the sapphire substrate 5 has a corner 53 formed at the boundary between the upper surface 50 and the side surface 52. A corner 53 ′ is formed at the boundary between the lower surface 51 and the side surface 52. A light emitting layer 55 is laminated on the upper surface 50, and an optical device 57 is formed on the light emitting layer 55.

  As shown in FIG. 2C, the thickness T2 of the sapphire substrate 5 before grinding is, for example, 1300 μm. The lower surface 51 of the sapphire substrate 5 is ground by the grinding apparatus 1 shown in FIG. Grinding is performed until T2 reaches, for example, 100 to 120 μm.

  In order to prevent chipping on the side surface 52 side of the sapphire substrate 5 during transport or the like, the sapphire substrate 5 is formed with a chamfered portion 54 by cutting out the corner portion 53 at a predetermined angle.

  The chamfered portion 54 is a slope 500 in which the corner portion 53 shown in FIG. 2B is cut out in a planar shape from the upper surface 50 toward the lower side on the outer peripheral side, and the height T1 of the chamfered portion 54 is the upper surface 50. As a reference, it is desirable to form the sapphire substrate 5 in a thickness direction of 50 μm or less.

  The chamfered portion 54 is desirably formed at the height T1 as described above, and an angle α formed by the line L1 extended from the inclined surface 500 and the upper surface 50 is 45 degrees or more and less than 90 degrees.

  In addition, as shown in FIG. 2B, the sapphire substrate 5 is formed by chamfering the corner portion 53 'to form a chamfered portion 54' shown in FIG. 2C. The chamfered portion 54 ′ is formed at a height T1 ′ similar to the height T1 of the chamfered portion 54, and the angle α formed between the parallel line L2 extended from the inclined surface 500 ′ and the lower surface 51 is 45 degrees or more and 90 degrees. It is desirable to form less than.

  In order to prevent the outer periphery of the sapphire substrate from being chipped when the sapphire substrate after grinding is conveyed, the lower limit of the height T1 of the chamfered portion 54 and the height T1 ′ of the chamfered portion 54 ′ is: The thickness is preferably 20 μm.

  The chamfered portions 54, 54 ′ are formed by, for example, applying a grindstone having a shape corresponding to the chamfered portions 54, 54 ′ to the side surface 52 and transferring the shape of the grindstone to the side surface 52, thereby forming the chamfered portions 54, 54 ′. be able to.

A sapphire substrate 5a shown in FIG. 3 is a second example of a sapphire substrate according to the present invention.
As shown in FIG. 3, in the sapphire substrate 5a, the light emitting layer 55 is not laminated on the upper surface 50a, and a chamfered portion 54a is formed with reference to the upper surface 50a.

  The thickness T4 of the sapphire substrate 5a before grinding is 1300 μm, for example, and the upper surface 50a of the sapphire substrate 5a is ground by the grinding apparatus 1 shown in FIG. 1, and the thickness T4 of the sapphire substrate 5a reaches 100 to 120 μm, for example. Until it is ground.

  The chamfered portion 54a is inclined 500a by inclining the side surface 52a side of the sapphire substrate 5a downward, and the height T3 of the chamfered portion 54a is 50 μm or less in the thickness direction of the sapphire substrate 5a with respect to the upper surface 50a. It is desirable to be formed.

  It is desirable that the chamfered portion 54a is formed at the height T3 as described above, and the angle α between the line L3 extended from the inclined surface 500a and the upper surface 50a is 45 degrees or more and less than 90 degrees.

  In addition, when conveying the ground sapphire substrate, in order to prevent chipping on the outer periphery of the sapphire substrate, the lower limit of the height T3 of the chamfered portion 54a is preferably set to 20 μm.

  As shown in FIG. 4, the annular frame 6 that supports the sapphire substrate 5 is made of metal, the central portion is open, and an adhesive protective tape is attached to the lower surface of the frame 6 so as to close the central portion. 7 is attached. Then, by sticking the upper surface 50 of the sapphire substrate 5 to the protective tape 7, the sapphire substrate 5 is integrated with the frame 6 through the protective tape 7.

  The chuck table 10 shown in FIGS. 5 and 6 includes a holding surface 11 that holds the sapphire substrate 5, a suction unit 12 that sucks the upper surface 50 of the sapphire substrate 5 from below, and a ring-shaped magnet 13 that supports the frame 6. A shaft portion 14 that rotatably supports the chuck table 10 and a suction hole 16 that is connected to the lower end of the suction portion 12 and communicates with the suction source 15 are provided.

  As shown in FIG. 6, the suction part 12 is formed of a porous member. The chuck table 10 transfers the sapphire substrate 5 integrated with the frame 6 through the protective tape 7 by transmitting the suction force generated from the suction source 15 to the suction unit 12 through the suction hole 16. 10 holding surfaces 11 can be sucked and held.

  As shown in FIG. 6, the surface of the chuck table 10 between the suction portion 12 and the ring-shaped magnet 13 is a slope 17 that is inclined downward by a predetermined angle on the magnet 13 side.

  The sapphire substrate 5 and the sapphire substrate 5a configured as described above are ground by the grinding apparatus 1 configured as described above. In the following, a series of operation examples for grinding the sapphire substrate 5 will be described.

  As shown in FIG. 4, the sapphire substrate 5 is inverted to expose the lower surface 51 upward, and the upper surface 50 faces the protective tape 7 integrated with the frame 6. Then, the sapphire substrate 5 is lowered and the upper surface 50 is adhered to the protective tape 7.

  As shown in FIG. 5, after the sapphire substrate 5 is supported by the frame 6 through the protective tape 7, the sapphire substrate 5 integrated with the frame 6 is lowered toward the chuck table 10 to hold the chuck table 10. Place on surface 11.

  After the sapphire substrate 5 is placed on the holding surface 11, the upper surface 50 of the sapphire substrate 5 is attracted and held by the holding surface 11 of the chuck table 10 and the lower part of the frame 6 is magnetically attached to the magnet 13. As a result, the frame 6 is supported below the position of the holding surface 11 by the magnetizing force of the magnet 13. Further, tension is generated on the protective tape 7, and the protective tape 7 is stretched along the inclined surface 17 of the chuck table 10.

  After the sapphire substrate 5 is sucked and held on the chuck table 10, the moving base 4 is moved in the Y-axis direction while rotating the chuck table 10 shown in FIG. 1, and the chuck table 10 is sent below the grinding means 20. At the same time, the grinding means 20 is actuated to rotate the grinding wheel 26 while the grinding feed means 30 lowers the grinding wheel 26 in the Z-axis direction.

  As shown in FIG. 7, the grinding wheel 26 is rotated in the direction of arrow A and lowered in the Z-axis direction indicated by arrow B to bring the grindstone 28 into contact with the lower surface 51 of the sapphire substrate 5 held on the chuck table 10. For example, grinding is performed until the thickness reaches 100 to 120 μm. During grinding, the grindstone 28 always passes through the center of rotation of the sapphire substrate 5.

  As described above, in the sapphire substrate 5, the chamfered portion 54 is formed with a height of 50 μm or less in the thickness direction of the sapphire substrate 5 with respect to the upper surface 50 or the lower surface 51, and the angle α of the chamfered portion 54 is 45 degrees or more and 90 degrees. Since it is formed at an angle of less than 50 degrees, the inclination angle with respect to the upper surface 50 or the lower surface 51 is larger than the conventional one. Therefore, the durability of the sapphire substrate 5 with respect to the pressing force during grinding by the grindstone 27 is improved, and the thickness of the sapphire substrate 5 can be ground to a thickness of 180 μm or less without causing chipping on the outer periphery of the sapphire substrate 5. .

  The grinding apparatus 1 shown in FIG. 1 grinds the sapphire substrate under the following processing conditions, and the presence and amount of chips generated on the sapphire substrate were confirmed.

〔Processing conditions〕
1 Workpiece: Sapphire substrate (1) Thickness: 1300 μm
(2) Chamfer width: 50 μm
2 Grinding conditions:
(1) Chuck table rotation speed: 500 rpm
(2) Grinding wheel rotation speed: 1000 rpm
(3) Grinding feed rate: 0.5 μm / sec

  When the inventor forms the chamfered portion 54 or the chamfered portion 54 ′ formed on the sapphire substrate 5 shown in FIG. 2, the height T1 in the thickness direction is determined based on the upper surface 50 or the lower surface 51 of the sapphire substrate 5. 100 μm, 90 μm, 80 μm, 70 μm, 60 μm, and 50 μm are formed, and the angle α shown in FIG. 2C is 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, and 70 degrees, respectively. 75 °, 80 °, and 85 ° were formed. Then, the upper surface 50 or the lower surface 51 of the sapphire substrate 5 was ground by the grinding apparatus 1 shown in FIG.

  As a result, when the chamfered portion 54 or the chamfered portion 54 ′ is formed to have a height of 50 μm or less, the chipping generated on the outer periphery of the sapphire substrate 5 even if the sapphire substrate 5 is ground to a thickness of 100 to 120 μm. Was confirmed to decrease. Moreover, it was confirmed that the chip | tip which generate | occur | produces in the outer periphery of the sapphire substrate 5 reduces as angle (alpha) is enlarged with 50 degree | times, 55 degree | times, 65 degree | times, 70 degree | times, 75 degree | times, 80 degree | times, and 85 degree | times. . However, it was confirmed that the function as the chamfered portion deteriorates when the angle exceeds 80 degrees.

  On the other hand, when the angle α is less than 45 degrees, it has been confirmed that chipping generated on the outer periphery of the sapphire substrate 5 increases.

  As shown by the above results, in order to prevent chipping from occurring on the outer periphery of the sapphire substrate 5 which is a hard substrate, the height of the chamfered portion formed on the sapphire substrate 5 is set to 50 μm or less. It has been confirmed that it is effective to form the angle α at least 45 degrees and less than 90 degrees. It was also confirmed that if the angle α is formed in the range of 50 degrees or more and 80 degrees or less, it is possible to more reliably prevent the outer periphery of the sapphire substrate from being chipped while having a function as a chamfered portion.

1: Grinding device 2a: Device base 2b: Standing base 3: Bellows 4: Moving base 5, 5a: Sapphire substrate 50, 50a: Upper surface 51, 51a: Lower surface
52, 52a: Side surface 53, 53 ′: Corner portion 54, 54 ′, 54a: Chamfered portion
55: Light emitting layer 56: Divided line 57: Device 58: Notch 500, 500 ', 500a: Slope 6: Frame 7: Protection tape 10: Chuck table 11: Holding surface 12: Suction part 13: Magnet 14: Shaft part 15 : Suction source 16: Suction hole 17: Slope 20: Grinding means 21: Spindle 22: Spindle housing 23: Holding part 24: Motor 25: Mounter 26: Grinding wheel 27: Bolt 28: Grinding wheel 30: Grinding feed means 31: Ball screw 32: Motor 33: Guide rail 34: Moving base

Claims (2)

Have a ring-shaped side surface extending from the outer periphery to the outer periphery of the other surface of the one surface of the sapphire substrate, a sapphire substrate before the surface of said other is ground,
Chamfered portion is formed at a corner formed by the corners and the other surface and the side surface formed by the one surface and the side surface of the sapphire substrate,
Chamfered portion is formed on one surface and the other surface to a thickness direction as a reference less 50μm height said, 45 degrees or more with respect to said one surface and said other surface on the outer peripheral side Formed at an angle of less than 90 degrees,
A sapphire substrate in which a light emitting layer is laminated on one surface of the sapphire substrate, the chamfered portion is formed on the basis of the one surface, and then the other surface is ground to a thickness of 100 to 120 μm.   The sapphire substrate according to claim 1, wherein the chamfered portion is formed to be inclined at an angle of not less than 50 degrees and not more than 80 degrees with respect to the one surface or the other surface.

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