Laser processing apparatus, laser processing method, and correction data generation method

Patent metadata

Field	Value
Publication number	US-2024227072-A1
Application number	US-202418611378-A
Country	US
Kind code	A1
Filing date	Mar 20, 2024
Priority date	Aug 23, 2019
Publication date	Jul 11, 2024
Grant date	—

Abstract

Laser processing apparatus includes movable mirror for changing paths of laser light for processing and measurement light, and stage for changing an incident angle of measuring light. Furthermore, laser processing apparatus includes lens for condensing laser light for processing and measurement light on processing point, controller for controlling laser oscillator, movable mirror, and stage based on corrected data for processing, and measurement processor for measuring a depth of keyhole generated at processing point. The corrected data for processing is data corrected so as to a deviation of an arrival position of at least one of laser light for processing and measurement light caused by chromatic aberration of lens on the surface of workpiece. With this configuration, an accurate depth of keyhole can be measured.

First claim

What is claimed is:

1 . A laser processing method performed by a laser processing apparatus including a movable mirror that changes a traveling direction of laser light for processing and a traveling direction of measurement light, a stage that changes an incident angle of the measurement light to the movable mirror, and a lens that condenses the laser light for processing and the measurement light on a processing point on a surface of a workpiece, the method comprising:
controlling the movable mirror and the stage based on corrected data for processing and irradiating the workpiece with the laser light for processing and the measurement light; and measuring a depth of a keyhole generated at the processing point by irradiation with the laser light for processing based on interference caused by an optical path difference between the measurement light reflected at the processing point and reference light, wherein the corrected data for processing is data obtained by correcting processing data generated in advance for processing the workpiece so that a deviation of an arrival position of at least one of the laser light for processing and the measurement light on the surface of the workpiece caused by chromatic aberration of a lens is eliminated.

2 . The laser processing method of claim 1 , wherein:
the laser processing apparatus includes a laser oscillator that oscillates the laser light for processing with respect to the processing point on the surface of a workpiece, the corrected data for processing includes
an output instruction value which indicates an intensity of the laser light for processing oscillated from the laser oscillator and is preset for each being the processing point,
a first instruction value indicating an operation amount of the movable mirror, and
a second instruction value indicating an operation amount of the stage.

3 . The laser processing method of claim 1 ,
wherein a wavelength of the laser light for processing and a wavelength of the measurement light are different from each other.

4 . The laser processing method of claim 1 ,
wherein the movable mirror is a galvano mirror and the stage is a piezo stage.

5 . The laser processing method of claim 1 ,
wherein the lens is an fθ lens.

6 . The laser processing method of claim 1 , wherein:
the laser processing apparatus includes a controller that controls a laser oscillator that oscillates the laser light for processing with respect to the processing point on the surface of a workpiece, the movable mirror, and the stage based on the corrected data for processing, the controller is configured to set a lattice pattern which is a range in which laser processing is performed, the controller is configured to select one lattice point from a plurality of lattice points included in the lattice pattern, the controller is configured to install a two-dimensional beam profiler at the selected lattice point, the controller is configured to set the scanning angle which is an operation amount of movable mirror as a first instruction value, the controller is configured to use the two-dimensional beam profiler to obtain the position at which laser light for processing reaches processing surface, the controller is configured to causes the processing surface to be irradiated with measurement light and uses the two-dimensional beam profiler to obtain the position where measurement light reaches the processing surface, the controller is configured to set a correction amount as a second instruction value which is the operation amount of stage, while referring to the measurement result of the two-dimensional beam profiler, so that the arrival position of laser light for processing and the arrival position of measurement light are coincident with each other, and the controller is configured to stores the first instruction value and the second instruction value as a corrected data for processing in the memory.

7 . The laser processing method of claim 1 ,
wherein the laser processing apparatus includes an optical interferometer that emits the measurement light to the processing point and generates an optical interference intensity signal based on interference caused by an optical path difference between the measurement light reflected at the processing point and the reference light, and the optical interferometer emits the measurement light for optical coherence tomography (OCT) measurement.

8 . The laser processing method of claim 7 ,
wherein wavelength of the measurement light is longer than wavelength of the laser light for processing.

9 . The laser processing method of claim 8 ,
wherein wavelength of the measurement light is 1300 nm.

10 . A correction data generation method performed by a laser processing apparatus including a movable mirror that changes a traveling direction of laser light for processing and a traveling direction of measurement light, a stage that changes an incident angle of the measurement light to the movable mirror, and a lens that condenses the laser light for processing and the measurement light on a processing point on a surface of a workpiece, the method comprising:
generating data for processing, in which an output intensity of the laser light for processing and an operation amount of the movable mirror that causes the laser light for processing to reach the processing point are set, for each processing point on the surface of the workpiece; calculating a first operation amount, which is an operation amount of the stage that causes the measurement light to reach a predetermined position, for each predetermined position on the surface of the workpiece; calculating a second operation amount, which is an operation amount of the stage that causes the measurement light to reach the processing point, based on the first operation amount, for each processing point; and generating corrected data for processing, which is obtained by correcting the data for processing so that a deviation of an arrival position of at least one of the laser light for processing and the measurement light caused by chromatic aberration of the lens is eliminated, by adding the second operation amount to the data for processing.

11 . The correction data generation method of claim 10 ,
wherein in calculating the second operation amount, when the processing point and the predetermined position do not coincide with each other, interpolation processing is performed using the first operation amount at a predetermined number of the predetermined positions in order of being closer to the processing point to calculate the second operation amount.

12 . The correction data generation method of claim 11 ,
wherein the predetermined position is set to a range of the surface of the workpiece corresponding to a movable range of the movable mirror, and is set such that the interpolation processing is executable within the range.

13 . The correction data generation method of claim 10 , wherein:
the laser processing apparatus includes a laser oscillator that oscillates the laser light for processing with respect to the processing point on the surface of a workpiece, the corrected data for processing includes
an output instruction value which indicates an intensity of the laser light for processing oscillated from the laser oscillator and is preset for each being the processing point,
a first instruction value indicating an operation amount of the movable mirror, and
a second instruction value indicating an operation amount of the stage.

14 . The correction data generation method of claim 10 ,
wherein a wavelength of the laser light for p

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Takechi Yohei
• Yokoyama Jun

Classifications

• B23K26/0665

  by beam condensation on the workpiece, e.g. for focusing · CPC title

• B23K26/082

  Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head · CPC title

• B23K26/705

  Beam measuring devices · CPC title

• B23K26/21

  by welding · CPC title

• B23K26/0648

  comprising lenses · CPC title