JP2014082418A - Laser processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser processing device capable of suppressing upsizing of the whole device even when holding means is made large in response to a larger diameter of a wafer.SOLUTION: A laser processing device comprises workpiece holding means for holding a workpiece and laser beam irradiation means for irradiating the workpiece held by the workpiece holding means with a laser beam. The laser beam irradiation means further comprises: laser beam oscillating means for oscillating a laser beam; a condenser which condenses the laser beams oscillated by the laser beam oscillating means and irradiates the workpiece held by the workpiece holding means with the condensed laser beams; an X-axis moving mechanism which moves the condenser in an X-axis direction; and a Y-axis moving mechanism which moves the condenser in a Y-axis direction orthogonal to the X-axis direction.

Description

  The present invention relates to a laser processing apparatus for performing laser processing on a workpiece such as a semiconductor wafer.

  In the semiconductor device manufacturing process, a plurality of regions are partitioned by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and devices such as ICs, LSIs, etc. are partitioned in the partitioned regions. Form. Then, the semiconductor wafer is cut along the streets to divide the region in which the device is formed to manufacture individual devices. In addition, an optical device wafer in which a gallium nitride compound semiconductor or the like is laminated on the surface of a sapphire substrate or silicon carbide substrate is also divided into optical devices such as individual light emitting diodes and laser diodes by cutting along the streets. Widely used.

  As a method of dividing the wafer along the street, a laser processing method has been attempted in which a pulsed laser beam having a wavelength that is transparent to the wafer is used, and the focused laser beam is aligned within the region to be divided and irradiated with the pulsed laser beam. ing. The dividing method using this laser processing method is to irradiate a pulse laser beam having a wavelength that is transparent to the wafer along the street from the back surface side of the wafer and irradiate the inside of the wafer to the street. A modified layer is continuously formed along the surface, and the wafer is divided into individual devices by applying an external force along a street whose strength is reduced by the formation of the modified layer. (For example, refer to Patent Document 1.)

  In addition, as a method of dividing the wafer along the street, a laser beam is formed by irradiating the pulse laser beam along the street formed on the wafer, using a pulse laser beam having a wavelength that absorbs the wafer. A method of breaking along the laser processed groove has been put into practical use. (For example, see Patent Document 2.)

  The laser processing apparatus for performing the laser processing described above includes a workpiece holding means for holding a workpiece, a laser beam irradiation means for irradiating the workpiece held by the workpiece holding means with a laser beam, and a workpiece A machining feed means for machining and feeding the holding means in the machining feed direction (X-axis direction) and an index feed means for indexing and feeding the workpiece holding means in the index feed direction (Y-axis direction) perpendicular to the machining feed direction are provided. Yes. (For example, refer to Patent Document 3.)

Japanese Patent No. 3408805 JP-A-10-305420 JP 2009-200027 A

  In recent years, in order to improve the productivity of semiconductor device manufacturing, there is a tendency to increase the diameter of the wafer to 300 mm and 450 mm, and the workpiece holding means for holding the workpiece such as a wafer also increases the diameter of the wafer. It is configured in the size corresponding to. Thus, since the moving path of the holding means becomes longer as the workpiece holding means becomes larger, there is a problem that the laser processing apparatus itself becomes larger and presses a clean room with a high unit price.

  The present invention has been made in view of the above-mentioned facts, and the main technical problem thereof is laser processing that can suppress the increase in the size of the entire apparatus even if the holding means is increased in response to the increase in the diameter of the wafer. To provide an apparatus.

In order to solve the above-mentioned main technical problem, according to the present invention, a workpiece holding means for holding a workpiece, and laser beam irradiation for irradiating a workpiece held on the workpiece holding means with a laser beam A laser processing apparatus comprising:
The laser beam irradiating means includes a laser beam oscillating means for oscillating a laser beam, a condenser for condensing the laser beam oscillated by the laser beam oscillating means and irradiating the workpiece held by the workpiece holding means, An X-axis movement mechanism that moves the condenser in the X-axis direction, and a Y-axis movement mechanism that moves the condenser in the Y-axis direction orthogonal to the X-axis direction,
A laser processing apparatus is provided.

The workpiece holding means includes a holding table having a holding surface for holding the workpiece, a rotation driving mechanism for rotating the holding table, and a Z axis perpendicular to the X axis direction and the Y axis direction. It is equipped with a Z-axis moving mechanism that moves in the direction.
The collector is mounted on a collector mounting member that is moved in the X-axis direction by the X-axis moving mechanism, and the collector mounting member is on the same axis line as the collector in the X-axis direction. An imaging means for detecting a processing area to be laser processed of the workpiece held on the holding table of the workpiece holding means is mounted.

  In the laser processing apparatus according to the present invention, the laser beam irradiation means includes an X-axis moving mechanism for moving the condenser in the X-axis direction and a Y-axis moving mechanism for moving the condenser in the Y-axis direction. It is not necessary to adopt a configuration in which the holding table of the workpiece holding means is moved in the X axis direction and the Y axis direction. Therefore, even if the holding table of the workpiece holding means is enlarged in response to the increase in the diameter of the wafer as the workpiece, the overall size of the apparatus can be suppressed.

The perspective view of the laser processing apparatus comprised according to this invention. The perspective view which decomposes | disassembles and shows the structural member of the workpiece holding means with which the laser processing apparatus shown in FIG. 1 is equipped. The perspective view of the collector support unit which comprises the laser beam irradiation means with which the laser processing apparatus shown in FIG. 1 is equipped. The perspective view which shows the state which decomposed | disassembled the Y-axis direction guide member and movable base which comprise the collector support unit shown in FIG. The perspective view which decomposes | disassembles and shows each member which comprises the collector support unit shown in FIG. The block block diagram of the laser beam irradiation means with which the laser processing apparatus shown in FIG. 1 is equipped. Explanatory drawing of the laser beam irradiated by the collector which comprises the laser beam irradiation means shown in FIG.

  Preferred embodiments of a laser processing apparatus configured according to the present invention will be described below in more detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view of a laser processing apparatus constructed according to the present invention. The laser processing apparatus shown in FIG. 1 includes a stationary base 2, a workpiece holding means 3 that is disposed on the stationary base 2 and holds a workpiece, and a workpiece that is disposed on the stationary base 2. A laser beam irradiation unit 4 is provided as a laser beam irradiation unit for irradiating a workpiece held by the holding unit 3 with a laser beam.

  The workpiece holding means 3 processes the holding table 31 having a holding surface 311a for holding the workpiece, a rotation drive mechanism 32 for rotating the holding table 31, and the holding table 31, as shown in FIG. The Z-axis direction indicated by the arrow Z, which is the focal position adjustment direction orthogonal to the X-axis direction indicated by the arrow X as the feed direction and the Y-axis direction indicated by the arrow Y as the index feed direction (perpendicular to the holding surface 311a of the holding table 31) A Z-axis moving mechanism 33 that moves in the right direction). The holding table 31 includes a suction chuck 311 formed of a porous material, and holds a workpiece such as a semiconductor wafer on a holding surface 311a that is an upper surface of the suction chuck 311 by suction means (not shown). It has become. The holding table 31 thus configured is provided with a clamp 34 for fixing an annular frame that supports a workpiece such as a semiconductor wafer via a protective tape.

  The rotation drive mechanism 32 includes a cylindrical rotation support member 321 that rotatably supports the holding table 31, and a pulse motor 322 disposed in the cylindrical rotation support member 321. The holding table 31 is rotated by driving the motor 322.

  The Z-axis moving mechanism 33 moves the table support member 331 that supports the holding table 31 and the rotation drive mechanism 32, and the table support member 331 in the Z-axis direction (direction perpendicular to the holding surface 311a of the holding table 31). It comprises a guide support member 332 that supports it and a moving motor 333 that is disposed on the upper surface of the guide support member 332 and moves the table support member 331 in the Z-axis direction. The table support member 331 includes a square top wall 331a and four side walls 331b that respectively hang down from the four sides of the top wall 331a. The rotation support member 321 is disposed on the top wall 331a of the table support member 331 thus configured. The guide support member 332 is formed in a square shape corresponding to the inner surfaces of the four side walls 331b constituting the table support member 331, and guides the inner surfaces of the four side walls 331b constituting the table support member 331 at four corners. A guide portion 332a that protrudes upward is provided. Therefore, by fitting the table support member 331 to the guide support member 332 from above, the table support member 331 is supported so as to be movable in the Z-axis direction along the guide portion 332 a of the guide support member 332. The moving motor 333 is a pulse motor, and a male screw 333b is formed on the drive shaft 333a. The male screw 333b is screwed into a female screw hole (not shown) provided at the center of the top wall 331a constituting the table support member 331. Accordingly, the table support member 331 is raised by rotating the movement motor 333 in one direction, and the table support member 331 is lowered by rotating the movement motor 333 in the other direction. In the Z-axis moving mechanism 33 configured as described above, the guide support member 332 is disposed on the stationary base 2 as shown in FIG.

  The laser beam irradiation unit 4 includes a support member 41 disposed on the stationary base 2, a casing 42 supported by the support member 41 and extending substantially horizontally, and a laser beam disposed on the casing 42. Irradiation means 5 and imaging means 43 for detecting a processing region to be laser processed are provided. The laser beam irradiating means 5 includes a pulse laser beam oscillating means 51 that oscillates a pulse laser beam, and a workpiece that is held on the holding table 31 of the workpiece holding means 3 by collecting the pulse laser beam oscillated by the pulse laser beam oscillating means 51. A collector 52 for irradiating the workpiece, and a collector support unit 6 that supports the collector 52 so as to be movable in the X-axis direction (machining feed direction) and the Y-axis direction (index feed direction) are provided. Yes. The pulse laser beam oscillating means 51 is composed of a pulse laser beam oscillator composed of a YAG laser oscillator or a YVO4 laser oscillator and a repetition frequency setting means attached thereto, and is disposed in the casing 42.

  The concentrator support unit 6 will be described with reference to FIGS. The collector support unit 6 in the illustrated embodiment includes a Y-axis direction guide member 61 mounted on the lower surface of the casing 42 and a movable base supported by the Y-axis direction guide member 61 so as to be movable in the Y-axis direction. A table 62 is provided. The Y-axis direction guide member 61 is provided with guide grooves 611 and 612 extending in the Y-axis direction on both sides in the X-axis direction. In addition, a bearing member 613 provided with a support hole 613a that rotatably supports a male screw rod constituting a Y-axis moving mechanism, which will be described later, projects downward at the center of one end of the Y-axis direction guide member 61 in the Y-axis direction. Is provided.

  As shown in FIG. 5, the movable base 62 includes a rectangular base main body 621 that is long in the X-axis direction, and supported portions 622 and 623 that extend upward from both ends of the base main body 621 in the X-axis direction. Yes. The base body 621 is provided with a guide hole 621a formed along the X-axis direction. Guided rails 622a and 623a that protrude outward and extend in the Y-axis direction are provided at the upper ends of the supported portions 622 and 623, respectively. The guided rails 622a and 623a are provided in the Y-axis direction guide member 61. By engaging with the guide grooves 611 and 612 formed, the moving base 62 is supported by the Y-axis direction guide member 61 so as to be movable along the Y-axis direction as shown in FIG. One supported portion 622 constituting the moving base 62 is provided with a support hole 622b for rotatably supporting a male screw rod constituting a Y-axis moving mechanism, which will be described later, and the other supported portion 623 is provided with the other supported portion 623. Is provided with a mounting hole 623b for mounting a motor for rotationally driving a male screw rod constituting a Y-axis moving mechanism described later.

  On the movable base 62 configured as described above, a condenser mounting member 63 for mounting the condenser 52 and an X-axis direction moving block disposed on the upper surface of the condenser mounting member 63 64 is arranged to be movable along the X-axis direction. That is, the X-axis direction moving block 64 disposed on the upper surface of the condenser mounting member 63 has a width corresponding to the width of the guide hole 621 a provided in the base body 621 constituting the moving base 62. As shown in FIG. 4, the guide body 621 is fitted into the guide hole 621a from below the base body 621 so as to be movable along the guide hole 621a in the X-axis direction. Further, the X-axis direction moving block 64 is provided with a female screw hole 641 penetrating in the X-axis direction as shown in FIG. A male screw rod constituting an X-axis moving mechanism described later is screwed into the female screw hole 641.

  As shown in FIG. 4, the light is condensed on the lower surface of the concentrator mounting member 63 disposed on the base body 621 of the movable base 62 together with the X-axis direction moving block 64 so as to be movable in the X-axis direction. A device 52 is attached. Accordingly, the condenser 52 is disposed on the base body 621 of the moving base 62 together with the condenser mounting member 63 so as to be movable in the X-axis direction. On the lower surface of the concentrator mounting member 63, laser processing of the workpiece held on the holding table 31 of the workpiece holding means 3 on the same axis line as the collector 52 in the X-axis direction should be performed. An imaging means 43 for detecting the machining area is attached.

  A Y-axis direction moving block 65 is disposed on the upper surface of the central portion of the base body 621 constituting the moving base 62. The Y-axis direction moving block 65 is provided with a female screw hole 651 that penetrates in the Y-axis direction as shown in FIGS. A male screw rod constituting a Y-axis moving mechanism described later is screwed into the female screw hole 651.

  On the lower surface of the base body 621 constituting the movable base 62, the pulse laser beam oscillated by the pulse laser beam oscillating means 51 on the same axis in the X-axis direction as the condenser 52 is directed toward the condenser 52. Reflecting means 53 for reflection is mounted. The reflection means 53 can be a reflection mirror or a prism.

  Continuing with reference to FIGS. 3 to 5, the laser beam irradiation means 5 in the illustrated embodiment moves in the X axis direction to move the condenser mounting member 63 to which the condenser 52 is mounted in the X axis direction. A mechanism 66, a condenser mounting member 63 to which the condenser 52 is mounted, and a Y-axis moving mechanism 67 for moving in the Y-axis direction a moving base 62 on which the reflecting means 53 is disposed are provided. The X-axis moving mechanism 66 is disposed along a guide hole 621 a provided in the base body 621 constituting the moving base 62, and is provided with a male screw rod 661 and a pulse motor 662 connected to one end of the male screw rod 661. It is made up of. The male screw rod 661 is screwed into a female screw hole 641 provided in the X-axis direction moving block 64, and the other end is rotated by a support hole 622 b provided in one supported portion 622 constituting the moving base 62. Supported as possible. The pulse motor 662 connected to one end of the male screw rod 661 is mounted by fitting into a mounting hole 623b provided in the other supported portion 623 constituting the moving base 62. The X-axis moving mechanism 66 configured as described above is mounted on the condenser mounting member 63 provided with the X-axis moving block 64 by rotating the pulse motor 662 in one direction or the other. The concentrator 52 is moved in the X-axis direction.

  The Y-axis moving mechanism 67 that moves the condenser 52 in the Y-axis direction is disposed along the Y-axis direction at the lower center portion of the Y-axis direction guide member 61, and the male screw rod 671. And a pulse motor 672 connected to one end of the motor. The male screw rod 671 is screwed into a female screw hole 651 provided in the Y-axis direction moving block 65, and the other end is connected to a bearing member 613 provided at one end central portion of the Y-axis direction guide member 61 in the Y-axis direction. It is rotatably supported by the formed support hole 613a. A pulse motor 672 connected to one end of the male screw rod 671 is attached to the lower surface of the Y-axis direction guide member 61. The Y-axis moving mechanism 67 configured as described above is a collection unit disposed on the moving base 62 to which the Y-axis direction moving block 65 is mounted by rotating the pulse motor 672 in one direction or the other direction. The condenser 52 mounted on the optical device mounting member 63 is moved in the Y-axis direction.

Next, the relationship between the pulse laser beam oscillating means 51, the reflecting means 53, and the condenser 52 constituting the laser beam irradiating means 5 will be described with reference to FIGS.
As shown in FIG. 6, the condenser mounting member 63 on which the condenser 52 and the imaging means 43 are mounted is configured to be movable in the X-axis direction indicated by the arrow X by the X-axis moving mechanism 66 as described above. Yes. The moving base 62 on which the condenser mounting member 63 and the reflecting means 53 are disposed is configured to be movable in the Y-axis direction indicated by the arrow Y by the Y-axis moving mechanism 67 as described above. . The pulse laser beam LB oscillated from the pulse laser beam oscillation means 51 is configured to irradiate the reflection means 53 along the Y-axis direction. Therefore, even if the moving base 62 on which the reflection means 53 is mounted moves in the Y-axis direction, the pulse laser beam LB oscillated from the pulse laser beam oscillation means 51 is always guided to a predetermined position of the reflection means 53. The pulse laser beam LB guided to the reflection means 53 in this way is reflected in the X-axis direction by the reflection means 53 and guided to the condenser 52. Therefore, the pulse laser beam LB reflected in the X-axis direction by the reflecting means 53 is always in a predetermined position of the collector 52 even if the collector mounting member 63 in which the collector 52 is disposed moves in the X-axis direction. Led to. That is, in the illustrated embodiment, as shown in FIG. 7, the pulse laser beam LB reflected by the reflecting means 53 in the X-axis direction passes through an opening 52 a formed in the condenser 52 so as to face the reflecting means 53. Then, the light is guided to a predetermined position of the direction changing mirror 521 constituting the condenser 52. The pulse laser beam LB guided to the direction conversion mirror is converted in the downward direction in FIG. 7, collected by the condenser lens 522, and irradiated onto the workpiece W held on the holding table 31.

As described above, in the illustrated laser processing apparatus, the laser beam irradiation means 5 includes the X-axis moving mechanism 66 that moves the collector mounting member 63 to which the collector 52 is mounted in the X-axis direction, and the collector. 52 is provided with a Y-axis moving mechanism 67 that moves in the Y-axis direction a moving base 62 on which a condenser mounting member 63 mounted with 52 and a reflecting means 53 are disposed. The holding table 31 need not be configured to move in the X-axis direction (machining feed direction) and the Y-axis direction (index feed direction). Therefore, even if the holding table 31 of the workpiece holding means 3 is enlarged corresponding to the increase in the diameter of the wafer as the workpiece, the increase in the size of the entire apparatus can be suppressed.
In the illustrated laser processing apparatus, the workpiece holding means 3 moves the holding table 31 having a holding surface for holding the workpiece in the X-axis direction (machining feed direction) and the Y-axis direction (index feed direction). Since the Z-axis moving mechanism 33 that moves in the Z-axis direction (focal position adjustment direction) orthogonal to the laser beam is provided, the laser beam irradiation means 5 is moved in the Z-axis direction in order to adjust the condensing point position of the laser beam by the condenser 52. It is not necessary to equip the condensing point position adjusting mechanism for moving and adjusting the position.
Further, in the illustrated laser processing apparatus, the concentrator 52 is mounted on a concentrator mounting member 63 that is moved in the X-axis direction by the X-axis moving mechanism 66. Since the image pickup means 43 for detecting the processing area to be laser processed of the workpiece held on the holding table 31 of the workpiece holding means 3 is mounted on the same axis in the X axis direction as the optical device 52, The alignment operation for aligning the processing area of the workpiece to be laser-processed, which is held on the holding table 31, with the condenser 52 that irradiates the laser beam is facilitated.

2: Stationary base 3: Workpiece holding means 31: Holding table 32: Rotation drive mechanism 33: Z-axis movement mechanism 4: Laser beam irradiation unit 43: Imaging means 5: Laser beam irradiation means 51: Pulse laser beam oscillation means 52: Collection Optical device 53: Reflecting means 6: Condenser support unit 61: Y-axis direction guide member 62: Moving base 63: Concentrator mounting member 64: X-axis direction moving block 65: Y-axis direction moving block 66: X-axis Movement mechanism 67: Y-axis movement mechanism

Claims (3)

In a laser processing apparatus comprising: a workpiece holding unit that holds a workpiece; and a laser beam irradiation unit that irradiates a laser beam onto the workpiece held by the workpiece holding unit.
The laser beam irradiating means includes a laser beam oscillating means for oscillating a laser beam, a condenser for condensing the laser beam oscillated by the laser beam oscillating means and irradiating the workpiece held by the workpiece holding means, An X-axis movement mechanism that moves the condenser in the X-axis direction, and a Y-axis movement mechanism that moves the condenser in the Y-axis direction orthogonal to the X-axis direction,
Laser processing equipment characterized by that.   The workpiece holding means includes a holding table having a holding surface for holding the workpiece, a rotation drive mechanism for rotating the holding table, and a Z axis perpendicular to the X axis direction and the Y axis direction. The laser processing apparatus according to claim 1, further comprising a Z-axis moving mechanism that moves in a direction.   The concentrator is mounted on a concentrator mounting member that is moved in the X-axis direction by the X-axis moving mechanism, and the concentrator mounting member is on the same axis as the concentrator in the X-axis direction. The laser processing apparatus according to claim 1 or 2, wherein an imaging means for detecting a processing region to be laser processed of the workpiece held on the holding table of the workpiece holding means is mounted.

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