JP2015085345A - Laser processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing device which can suppress cost relating to a chuck table.SOLUTION: A laser processing device (2) includes a chuck table (10), and laser beam irradiation means (12) for irradiating a workpiece (11) held on the chuck table with a laser beam (L). The chuck table includes: a holding block (68) having a holding surface (70a) and a first suction passage (70c) passing through from the holding surface to a rear surface (70b); a support base (62) having a support surface (62a) for supporting the holding block and a second suction passage (62c) passing through from the support surface to a rear surface (62b); and a base part (50) having a placing surface (52a) on which the support base is placed and a negative pressure transmission part (54) communicating with a negative pressure source. The plurality of holding blocks are detachably mounted on the support base so as to separate from each other, and a laser beam clearance groove (76) is formed by an interval of the adjacent holding blocks.

Description

  The present invention relates to a laser processing apparatus that processes a plate-like workpiece by irradiating a laser beam.

  A disk-shaped wafer having a device such as an IC formed on the surface is diced along a division line (street) and divided into a plurality of chips corresponding to each device (see, for example, Patent Document 1). This chip is incorporated into an electronic device together with a heat radiating plate having a size suitable for the chip, for example, so that heat generated by the device can be efficiently discharged.

The heat radiating plate is formed by irradiating a metal plate such as stainless steel with a laser beam and dividing the metal plate into a desired size. For example, a laser beam oscillated using CO ₂ as a laser medium is used for dividing the metal plate, and a cooling medium for cooling the metal plate is sprayed on the irradiation region (see, for example, Patent Document 2).

  In a laser processing apparatus that processes a plate-like workpiece such as a wafer or a metal plate, damage to the chuck table due to a laser beam penetrating the workpiece becomes a problem. Therefore, in recent years, a technique has been proposed in which a groove is formed corresponding to an irradiation region of a laser beam, thereby reducing the power of the laser beam irradiated to the chuck table and suppressing damage (see, for example, Patent Document 3). ).

JP-A-10-323779 JP 2000-61677 A JP2013-121598A

  By the way, in processing of a metal plate or a glass substrate, a laser beam having a very large power is used. In this case, in order to appropriately prevent damage to the chuck table, a considerably deep groove must be formed in the chuck table. Must not. However, since it is not easy to form such a deep groove in the chuck table, there is a problem that the cost for the chuck table is increased.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a laser processing apparatus capable of suppressing the cost associated with the chuck table.

  According to the present invention, a plate-like workpiece that is partitioned by a plurality of division lines that intersect each other is held by a holding surface, and the division line of the workpiece that is held by the chuck table is A laser beam irradiation means for irradiating a laser beam along the laser beam irradiation means for cutting the workpiece into a plurality of chips, wherein the chuck table has a holding surface corresponding to the chip of the workpiece, A first suction path penetrating from the holding surface to the back surface, a plurality of holding blocks paired with each chip, a support surface for supporting the holding block, and penetrating from the support surface to the back surface A support base having a second suction path connected to the first suction path; a mounting surface on which the support base is placed; and a negative pressure source in communication with the second suction path. A negative pressure transmission part for transmitting negative pressure to the second suction path; The plurality of holding blocks are detachably mounted at positions corresponding to the chips of the support base so as to be separated from each other, and the work piece is separated by the interval between the holding blocks adjacent to each other. There is provided a laser processing apparatus characterized in that a laser beam escape groove corresponding to the scheduled division line is formed.

  In the present invention, a concave portion is formed on the holding surface side of the holding block, and a suction pad positioned so that the suction portion protrudes from the holding surface communicates with the first suction path in the concave portion. It is preferable that it is disposed.

  In the laser processing apparatus of the present invention, the chuck table includes a base portion, a support base placed on the base portion, and a plurality of holding blocks that are detachably attached to the support base. Since the laser beam escape grooves corresponding to the division lines to be processed are formed according to the interval between the holding blocks to be processed, the depth of the laser beam escape grooves can be easily changed by using the holding blocks having different heights.

  That is, even when a deep laser beam escape groove is formed, the cost related to the chuck table can be suppressed. In addition, even if the holding surface that holds the workpiece is damaged by laser beam irradiation, the holding surface can be restored to an appropriate state by simply replacing the holding block. Compared to the cost associated with the chuck table.

It is a perspective view which shows typically the structural example of a laser processing apparatus. It is a perspective view which shows the structural example of a chuck table typically. It is a disassembled perspective view which shows the structural example of a chuck table typically. It is a disassembled perspective view which shows the structural example of a holding block typically. It is a partial cross section side view which shows typically an example of the processing method using a laser processing apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing a configuration example of a laser processing apparatus according to the present embodiment. As shown in FIG. 1, the laser processing apparatus 2 includes a base 4 that supports each component. The base 4 includes a base 6 and a column part 8 erected at the rear end of the base 6.

  A chuck table 10 that sucks and holds the plate-like workpiece 11 is disposed on the upper surface of the base 6. The workpiece 11 is a disk-shaped plate made of a material such as metal, glass, or semiconductor, and is partitioned into a plurality of regions by a plurality of division lines (streets) that intersect each other. A plurality of chips can be obtained by dividing the workpiece 11 along the division line.

  A support arm 8 a extending forward is provided on the upper portion of the column portion 8, and laser processing for irradiating a laser beam toward the workpiece 11 held on the chuck table 10 is provided at the tip of the support arm 8 a. A head (laser beam irradiation means) 12 is installed. Further, an imaging unit 14 that images the workpiece 11 is provided at a position adjacent to the laser processing head 12.

  Below the chuck table 10 is provided an X-axis moving mechanism (machining feed means) 16 that moves the chuck table 10 in the machining feed direction (X-axis direction). The X-axis moving mechanism 16 includes a pair of X-axis guide rails 18 that are fixed to the upper surface of the base 6 and are parallel to the X-axis direction.

  An X-axis moving table 20 is slidably installed on the X-axis guide rail 18. A nut portion (not shown) is fixed to the rear surface side (lower surface side) of the X-axis moving table 20, and an X-axis ball screw 22 parallel to the X-axis guide rail 18 is screwed to the nut portion. Yes.

  An X-axis pulse motor 24 is connected to one end of the X-axis ball screw 22. When the X-axis ball screw 22 is rotated by the X-axis pulse motor 24, the X-axis moving table 20 moves in the X-axis direction along the X-axis guide rail 18. An X-axis scale 26 for detecting the position of the X-axis moving table 20 in the X-axis direction is installed at a position adjacent to the X-axis guide rail 18.

  On the surface side (upper surface side) of the X-axis movement table 20, a Y-axis movement mechanism (index feed means) 28 for moving the chuck table 10 in an index feed direction (Y-axis direction) orthogonal to the machining feed direction is provided. Yes. The Y-axis moving mechanism 28 includes a pair of Y-axis guide rails 30 that are fixed to the upper surface of the X-axis moving table 20 and are parallel to the Y-axis direction.

  A Y-axis moving table 32 is slidably installed on the Y-axis guide rail 30. A nut portion (not shown) is fixed to the rear surface side (lower surface side) of the Y-axis moving table 32, and a Y-axis ball screw 34 parallel to the Y-axis guide rail 30 is screwed to the nut portion. Yes.

  A Y-axis pulse motor 36 is connected to one end of the Y-axis ball screw 34. When the Y-axis ball motor 34 is rotated by the Y-axis pulse motor 36, the Y-axis moving table 32 moves in the Y-axis direction along the Y-axis guide rail 30. A Y-axis scale 38 for detecting the position of the Y-axis moving table 32 in the Y-axis direction is installed at a position adjacent to the Y-axis guide rail 30.

  A support base 40 is provided on the surface side (upper surface side) of the Y-axis moving table 32. On the upper part of the support base 40, the chuck table 10 is arranged. The chuck table 10 is connected to a rotation mechanism (not shown) provided on the support base 40 and rotates around the Z axis.

  FIG. 2 is a perspective view schematically illustrating a configuration example of the chuck table 10, and FIG. 3 is an exploded perspective view schematically illustrating a configuration example of the chuck table 10. As shown in FIGS. 2 and 3, the chuck table 10 includes a disk-shaped base portion 50.

  A circular recess 52 (FIG. 3) is provided on the upper surface 50 a side of the base portion 50. A negative pressure transmitting portion 54 for applying a negative pressure to the workpiece 11 is formed on the bottom surface (mounting surface) 52 a of the recess 52.

  The negative pressure transmission part 54 includes a first groove 54a extending in a first direction D1 parallel to the upper surface 50a of the base part 50, and a second perpendicular to the first direction D1 parallel to the upper surface 50a of the base part 50. It consists of six second grooves 54b extending in the direction D2. That is, in the negative pressure transmission portion 54, the first groove 54a and the second groove 54b are orthogonal to each other.

  In the center of the first groove 54a constituting the negative pressure transmission portion 54, a suction path 50c that leads to the lower surface 50b side of the base portion 50 is provided. The negative pressure transmission unit 54 is connected to a negative pressure source (not shown) through the suction path 50c.

  An annular groove 56 surrounding the negative pressure transmission portion 54 is formed on the bottom surface 52 a of the recess 52, and a plurality of screw holes 58 are formed in a region between the negative pressure transmission portion 54 and the groove 56. Is provided. An O-ring 60 made of a material such as rubber is disposed in the groove 56.

  In a state where the O-ring 60 is disposed in the groove 56, a circular support base 62 that matches the shape of the recess 52 is placed on the bottom surface 52 a of the recess 52. In the central region of the support base 62, a plurality of through holes (second suction paths) 62c (see FIG. 5) that penetrate the support base 62 from the front surface (support surface) 62a to the back surface 62b are provided. The plurality of through holes 62 c are arranged at a predetermined interval corresponding to the second groove 54 b of the negative pressure transmission portion 54.

  A plurality of openings 64 corresponding to the screw holes 58 of the base portion 50 are formed in the outer peripheral portion of the support base 62. The support base 62 is fixed to the base portion 50 by tightening the screws 66 into the screw holes 58 through the openings 64. By fixing the support base 62 to the base portion 50, the plurality of through holes 62 c are connected to the negative pressure transmission portion 54.

  A plurality of holding blocks 68 are arranged on the surface 62 a side of the support base 62. Each holding block 68 is disposed so as to be separated from each other at a position corresponding to the through hole 62 c of the support base 62. The interval between adjacent holding blocks 68 is, for example, about 1 mm to 2 mm, but is not necessarily limited thereto.

  FIG. 4 is an exploded perspective view schematically showing a configuration example of the holding block 68. As shown in FIG. 4, the holding block 68 includes a holding block main body 70 having a rectangular parallelepiped shape. The upper surface of the holding block body 70 is a holding surface 70 a that holds the workpiece 11. The holding surface 70 a is brought into contact with a position corresponding to each chip of the workpiece 11.

  The holding block body 70 is formed with a through hole (first suction path) 70c that penetrates the holding block body 70 from the holding surface 70a to the back surface 70b. On the holding surface 70a side of the through hole 70c, a pad arrangement portion (concave portion) 70d for arranging the suction pad 72 is provided. The suction pad 72 is made of a material such as rubber and is disposed in the pad placement portion 70d so that the suction portion 72a at the upper end slightly protrudes from the holding surface 70a.

  Inside the suction pad 72, a flow path 72c is formed from the suction portion 72a to the lower end portion 72b of the suction pad 72, and the flow path 72c penetrates when the suction pad 72 is placed in the pad placement portion 70d. Connected to the hole 70c.

  A screw groove (not shown) is formed on the back surface 70b side of the through hole 70c, and a fixing screw 74 for fixing the holding block 68 to the support base 62 is tightened. With the holding block 68 placed on the surface 62a side of the support base 62, the holding block 68 is supported by tightening the fixing screw 74 into the through hole 70c of the holding block 68 through the through hole 62c of the support base 62. Fixed to the base 62.

  Inside the fixing screw 74, there is formed a flow path 74c that leads from the upper end 74a to the lower end 74b of the fixing screw 74. When the fixing screw 74 is tightened into the through hole 70c of the holding block 68, the flow path 74c. Is connected to the through hole 70c. Further, the holding block 68 is fixed to the support base 62, whereby the through hole 62c and the through hole 70c are connected. The holding block 68 is detachable from the support base 62.

  In the chuck table 10 configured as described above, the negative pressure of the negative pressure source is held by the holding block 68 through the suction path 50c, the negative pressure transmission portion 54, the through hole 62c, and the through holes 70c (flow paths 72c and 74c). It acts on the surface 70a (the suction portion 72a of the suction pad 72). The airtightness of the negative pressure transmission portion 54 is maintained by sealing the bottom surface 52 a of the recess 52 and the back surface 62 b of the support base 62 by the O-ring 60.

  In the chuck table 10, a laser beam escape groove 76 that reduces the power of the laser beam penetrating the workpiece 11 is formed by the interval between the adjacent holding blocks 68. The holding block 68 is fixed at a position corresponding to each chip after division so that the laser beam escape groove 76 is formed corresponding to the planned division line of the workpiece 11.

  Next, an example of a processing method using the laser processing apparatus 2 according to the present embodiment will be described. FIG. 5 is a partial cross-sectional side view schematically showing an example of a processing method using the laser processing apparatus 2 according to the present embodiment.

  First, a holding step for sucking and holding the workpiece 11 on the chuck table 10 of the laser processing apparatus 2 is performed. In the holding step, the workpiece 11 is placed on the chuck table 10 with the back surface 11b side of the workpiece 11 facing the holding surface 70a of the chuck table 10 as shown in FIG. At this time, the division line of the workpiece 11 is positioned above the laser beam escape groove 76.

  When the negative pressure source is operated in this state, the negative pressure as shown by the broken arrow in FIG. 5A acts on the back surface 11 b of the workpiece 11, and the workpiece 11 holds the chuck table 10. The surface 70a is sucked and held. Since the suction portion 72a of the suction pad 72 is made of a material such as rubber, it is slightly deformed when the workpiece 11 is sucked and held, and is positioned at the same height as the holding surface 70a. As a result, the back surface 11 of the workpiece 11 is in contact with the holding surface 70a (see FIG. 5B).

  After the holding step, a dividing step is performed in which the workpiece 11 is irradiated with a laser beam and divided into a plurality of chips. In the dividing step, first, the chuck table 10 is moved by the X-axis moving mechanism 16 and the Y-axis moving mechanism 28, and the laser processing head 12 is positioned above the planned dividing line of the workpiece 11.

  Next, as shown in FIG. 5B, the laser processing head 12 and the chuck table 10 are relatively moved while irradiating the laser beam L from the laser processing head 12 toward the surface 11 a of the workpiece 11. As a result, the laser beam L is irradiated along the planned division line of the workpiece 11, and the workpiece 11 is divided into chips.

  In the chuck table 10 according to the present embodiment, the laser beam escape groove 76 for reducing the power of the laser beam L and suppressing the damage is formed by the gap between the adjacent holding blocks 68. Can be properly suppressed.

  Further, in the chuck table 10 of the present embodiment, the depth of the laser beam escape groove 76 is determined by the height h of the holding block 68. Therefore, by using the holding block 68 having a different height, the laser beam escape groove 76 is formed. The depth can be easily changed.

  That is, even when it is necessary to form the deep laser beam escape groove 76, the cost related to the chuck table 10 can be suppressed. The depth of the laser beam escape groove 76 can be arbitrarily set according to the power of the laser beam L to be used.

  Further, even when the holding surface 70a holding the workpiece 11 is damaged by the irradiation of the laser beam L, the holding surface 70a can be restored to an appropriate state simply by replacing the damaged holding block 68, so that a new chuck Compared with the case where the table 10 is prepared, the cost related to the chuck table 10 can be suppressed.

  The configurations, methods, and the like according to the above embodiments can be appropriately modified and implemented without departing from the scope of the object of the present invention.

2 Laser processing device 4 Base 6 Base 8 Column 8a Support arm 10 Chuck table 12 Laser processing head (laser beam irradiation means)
14 Imaging unit 16 X-axis moving mechanism (processing feed means)
18 X-axis guide rail 20 X-axis moving table 22 X-axis ball screw 24 X-axis pulse motor 26 X-axis scale 28 Y-axis moving mechanism (index feed means)
30 Y-axis guide rail 32 Y-axis moving table 34 Y-axis ball screw 36 Y-axis pulse motor 38 Y-axis scale 40 Support base 50 Base 50a Upper surface 50b Lower surface 50c Suction path 52 Recessed portion 52a Bottom surface (mounting surface)
54 Negative pressure transmission portion 54a First groove 54b Second groove 56 Groove 58 Screw hole 60 O-ring 62 Support base 62a Surface (support surface)
62b Back surface 62c Through hole (second suction path)
64 Opening 66 Screw 68 Holding block 70 Holding block body 70a Holding surface 70b Back surface 70c Through hole (first suction path)
70d Pad placement part (recess)
72 suction pad 72a suction part 72b lower end part 72c flow path 74 fixing screw 74a upper end part 74b lower end part 74c flow path 76 laser beam escape groove 11 work piece 11a surface 11b back face D1 first direction D2 second direction

Claims (2)

A chuck table that holds a plate-like workpiece divided by a plurality of division lines that intersect each other with a holding surface, and a laser beam is irradiated along the division lines of the workpiece held on the chuck table. A laser beam irradiation means for cutting a workpiece into a plurality of chips, and a laser processing apparatus comprising:
The chuck table
A plurality of holding blocks each having a holding surface corresponding to the chip of the workpiece and a first suction path penetrating from the holding surface to the back surface;
A support base having a support surface that supports the holding block, and a second suction path that penetrates from the support surface to the back surface and is connected to the first suction path;
A base portion having a placement surface on which the support base is placed, and a negative pressure transmission portion that communicates with a negative pressure source and transmits a negative pressure to the second suction path of the support base. Prepared,
The plurality of holding blocks are:
Removably mounted at positions corresponding to the chips of the support base so as to be separated from each other,
2. A laser processing apparatus according to claim 1, wherein a laser beam escape groove corresponding to the division line of the workpiece is formed by an interval between the holding blocks adjacent to each other. A concave portion is formed on the holding surface side of the holding block,
The laser processing apparatus according to claim 1, wherein a suction pad positioned so that a suction portion protrudes from the holding surface is communicated with the first suction path.

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