Laser processing apparatus
A laser beam irradiation unit of a laser processing apparatus includes a first splitting unit that causes a laser beam emitted from a laser oscillator to branch into a first optical path and a second optical path, a first beam condenser that focuses the laser beam having been introduced to the first optical path, and a second beam condenser that focuses the laser beam having been introduced to the second optical path. The laser beam irradiation unit further includes a second splitting unit on the first optical path between the first splitting unit and the first beam condenser that splits the laser beam into at least two laser beams, and a laser beam scanning unit on the second optical path between the first splitting unit and the second beam condenser that executes scanning with the laser beam and introduces the laser beam to the second beam condenser.
1 . A laser processing apparatus comprising:
a holding table that holds a workpiece;
a laser beam irradiation unit that focuses a pulsed laser beam and irradiates the workpiece held on the holding table with the laser beam to execute processing and forms laser-processed grooves in the workpiece; and
a movement unit that relatively moves the holding table and a focal point of the laser beam, the movement unit being configured to move the holding table and the focal point of the laser beam in a processing feed (X-axis) direction, wherein
the laser beam irradiation unit includes
a laser oscillator,
a first splitting unit that causes the laser beam emitted from the laser oscillator to branch into a first optical path and a second optical path,
a first beam condenser that focuses the laser beam having been introduced to the first optical path,
a second beam condenser that focuses the laser beam having been introduced to the second optical path,
a second splitting unit that is disposed on the first optical path between the first splitting unit and the first beam condenser and that splits the laser beam having been introduced to the first optical path into at least two laser beams, and
a laser beam scanning unit that is disposed on the second optical path between the first splitting unit and the second beam condenser and that executes scanning with the laser beam having been introduced to the second optical path and introduces the laser beam to the second beam condenser.
2 . The laser processing apparatus according to claim 1 , wherein
the laser beam focused by the first beam condenser is positioned forward in the processing feed (X-axis) direction from the position the laser beam is focused by the second beam condenser as defined by the direction of movement of the holding table such that the laser beam focused by the first beam condenser is focused on a position of the workpiece prior to the laser beam focused by the second beam condenser being focused on the same position of the workpiece.
3 . The laser processing apparatus according to claim 1 , wherein
the second splitting unit splits the laser beam in a width (Y-axis) direction of a planned dividing line set in the workpiece to form at least two lines of laser-processed grooves along the planned dividing line, the width (Y-axis) direction being perpendicular to the processing feed direction.
4 . The laser processing apparatus according to claim 1 , wherein
the laser beam scanning unit includes
a polygon scanner that executes scanning with the laser beam in the processing feed direction of the movement unit and introduces the laser beam to the second beam condenser, and
an acousto-optic element that is disposed on the first optical path between the laser oscillator and the polygon scanner and that executes scanning with the laser beam in a width direction of a planned dividing line set in the workpiece, the width (Y-axis) direction being perpendicular to the processing feed direction.
5 . The laser processing apparatus according to claim 1 , wherein
the movement unit includes a beam condenser movement unit that moves the first beam condenser in a direction parallel to an upper surface of the workpiece, relative to the second beam condenser.
6 . The laser processing apparatus according to claim 1 , wherein
the laser beam irradiation unit further includes
a third splitting unit that is disposed on an optical path between the laser oscillator and the first splitting unit and that causes the laser beam emitted from the laser oscillator to further branch into a third optical path,
a third beam condenser that focuses the laser beam having been introduced to the third optical path, and
a fourth splitting unit that is disposed on the third optical path between the third splitting unit and the third beam condenser and that splits the laser beam having been introduced to the third optical path into at least two laser beams, and
the laser beam focused by the first beam condenser and the laser beam focused by the third beam condenser are separate on sides opposite to each other across the laser beam focused by the second beam condenser, in a processing feed direction of the movement unit.
7 . The laser processing apparatus according to claim 1 , wherein
the laser beam irradiation unit further includes
a third splitting unit that is disposed on the first optical path between the first splitting unit and the second splitting unit and that causes the laser beam having been introduced to the first optical path to further branch into a third optical path,
a third beam condenser that focuses the laser beam having been introduced to the third optical path, and
a fourth splitting unit that is disposed on the third optical path between the third splitting unit and the third beam condenser and that splits the laser beam having been introduced to the third optical path into at least two laser beams, and
the laser beam focused by the first beam condenser and the laser beam focused by the third beam condenser are separate on sides opposite to each other across the laser beam focused by the second beam condenser, in a processing feed direction of the movement unit.
8 . The laser processing apparatus according to claim 1 , wherein the second splitting unit is a Wollaston prism.
9 . The laser processing apparatus according to claim 1 , wherein the first beam condenser focuses each of the laser beams arising from splitting into at least two beams by the second splitting unit and irradiates the workpiece held on the holding table with each laser beam.
10 . The laser processing apparatus according to claim 1 , further comprising an output power adjustment mechanism disposed on the first optical path between the first splitting unit and the second splitting unit, the output power adjustment mechanism being configured to adjust the output power of the laser beam that has been introduced to the first optical path.
11 . The laser processing apparatus according to claim 4 , wherein the second beam condenser focuses the laser beam on the second optical path, with which scanning has been executed in the width (Y-axis) direction by the acousto-optic element and scanning has been executed in the processing (X-axis) direction by the polygon scanner, on the workpiece held on a holding surface of the holding table and irradiates the workpiece with the laser beam.
12 . The laser processing apparatus according to claim 3 , wherein
the laser beam scanning unit includes
a polygon scanner that executes scanning with the laser beam in the processing feed direction of the movement unit and introduces the laser beam to the second beam condenser, and
an acousto-optic element that is disposed on the first optical path between the laser oscillator and the polygon scanner and that executes scanning with the laser beam in a width direction of a planned dividing line set in the workpiece, the width (Y-axis) direction being perpendicular to the processing feed direction.
13 . The laser processing apparatus according to claim 12 , wherein the second beam condenser focuses the laser beam on the second optical path, with which scanning has been executed in the width (Y-axis) direction by the acousto-optic element and scanning has been executed in the processing (X-axis) direction by the polygon scanner, on the workpiece held on a holding surface of the holding table and irradiates the workpiece with the laser beam.
14 . The laser processing apparatus according to claim 13 , wherein the workpiece comprises a function layer, and wherein
the functional layer of the workpiece is split when the at least two lines of laser-processed grooves are formed along the planned dividing line; and wherein
the laser beam focused by the second beam condenser executes an inside laser grooving of forming the wide-width laser-processed groove that covers the region between the two lines of the laser-processed grooves formed by the laser beam focused by the first beam condenser.
15 . The laser processing apparatus according to claim 14 , wherein the movement unit is configured to adjust the relative distance in the processing (X-axis) direction between the first beam condenser and the second beam condenser.
16 . The laser processing apparatus according to claim 14 , further comprising a processing point nozzle that permits passing of the laser beam focused by the second beam condenser.
17 . The laser processing apparatus according to claim 2 , further comprising a processing point nozzle, wherein
the processing point nozzle includes
an upper wall located under the second beam condenser and having a first opening permits passing of the laser beam focused by the second beam condenser,
two sidewalls disposed to hang down from both side edges of the upper wall and opposed each other in the processing feed (X-axis) direction, one of the two sidewalls having a second opening,
an air inflow port surrounded by the upper wall and the two sidewalls and made at one end part in an indexing feed (Y-axis) direction perpendicular to the processing feed (X-axis) direction, and
an air suction port surrounded by the upper wall and the two sidewalls and made at the other end part in the indexing feed (Y-axis) direction.