Laser processing device and laser processing method

A laser processing method repeatedly performing:

• performing a control of presenting, on a spatial light modulator, a hologram for modulating a phase of light in each of a plurality of pixels arranged two-dimensionally;
• performing a light modulation of inputting laser light output from a laser light source to the spatial light modulator, and performing phase modulation of the laser light by the hologram;
• and
• performing a focusing of focusing the laser light after the phase modulation, wherein
• in the control, the spatial light modulator presents the hologram for simultaneously focusing the laser light after the phase modulation on a plurality of irradiation points in a processing object by the focusing, and
• at least one of a shape and a size of a processing region defined by the plurality of irradiation points in a first plane intersecting an optical axis of the laser light after the phase modulation with which the processing object is irradiated and a processing region defined by the plurality of irradiation points in a second plane intersecting the optical axis and separated from the first plane in a direction of the optical axis is set different from each other, and wherein
• in the control, light intensities of the plurality of irradiation points in the first plane and light intensities of the plurality of irradiation points in the second plane are simultaneously controlled independently of each other.

A laser processing apparatus comprising:

• a spatial light modulator configured to input laser light output from a laser light source, present a hologram for modulating a phase of the laser light in each of a plurality of pixels arranged two-dimensionally, and output laser light after phase modulation by the hologram;
• a focusing optical system provided at a subsequent stage of the spatial light modulator;
• and
• a control unit configured to present, on the spatial light modulator, the hologram for focusing the laser light after the phase modulation output from the spatial light modulator on a plurality of irradiation points in a processing object by the focusing optical system, wherein
• the control unit is configured to set at least one of a shape and a size of a processing region defined by the plurality of irradiation points in a first plane intersecting an optical axis of the laser light after the phase modulation with which the processing object is irradiated and a processing region defined by the plurality of irradiation points in a second plane intersecting the optical axis and separated from the first plane in a direction of the optical axis to be different from each other, and wherein
• the laser processing apparatus further comprises:
• an observation light source configured to irradiate the processing object with observation light;
• and
• a photodetector configured to detect the observation light reflected from the processing object, wherein
• the control unit is configured to determine a processing state at each irradiation point based on a detection result by the photodetector, and control a presenting time of the hologram for the first and second planes according to the processing state.

A laser processing apparatus comprising:

• a spatial light modulator configured to input laser light output from a laser light source, present a hologram for modulating a phase of the laser light in each of a plurality of pixels arranged two-dimensionally, and output laser light after phase modulation by the hologram;
• a focusing optical system provided at a subsequent stage of the spatial light modulator;
• and
• a control unit configured to present, on the spatial light modulator, the hologram for focusing the laser light after the phase modulation output from the spatial light modulator on a plurality of irradiation points in a processing object by the focusing optical system, wherein
• the control unit is configured to set at least one of a shape and a size of a processing region defined by the plurality of irradiation points in a first plane intersecting an optical axis of the laser light after the phase modulation with which the processing object is irradiated and a processing region defined by the plurality of irradiation points in a second plane intersecting the optical axis and separated from the first plane in a direction of the optical axis to be different from each other, and wherein
• when the hologram is changed, the control unit is configured to present, on the spatial light modulator, a hologram with which a light intensity of the laser light is less than a processing threshold value at any portion in the processing object during a period from erasing a certain hologram to presenting another hologram.

A laser processing method repeatedly performing:

• performing a control of presenting, on a spatial light modulator, a hologram for modulating a phase of light in each of a plurality of pixels arranged two-dimensionally;
• performing a light modulation of inputting laser light output from a laser light source to the spatial light modulator, and performing phase modulation of the laser light by the hologram;
• and
• performing a focusing of focusing the laser light after the phase modulation, wherein
• in the control, the spatial light modulator presents the hologram for focusing the laser light after the phase modulation on a plurality of irradiation points in a processing object by the focusing, and
• at least one of a shape and a size of a processing region defined by the plurality of irradiation points in a first plane intersecting an optical axis of the laser light after the phase modulation with which the processing object is irradiated and a processing region defined by the plurality of irradiation points in a second plane intersecting the optical axis and separated from the first plane in a direction of the optical axis is set different from each other, and wherein
• the laser processing method further comprises:
• performing a photodetection of irradiating the processing object with observation light, and detecting the observation light reflected from the processing object, wherein
• in the control, a processing state at each irradiation point is determined based on a detection result by the photodetection, and a presenting time of the hologram for the first and second planes is controlled according to the processing state.

A laser processing method repeatedly performing:

• performing a control of presenting, on a spatial light modulator, a hologram for modulating a phase of light in each of a plurality of pixels arranged two-dimensionally;
• performing a light modulation of inputting laser light output from a laser light source to the spatial light modulator, and performing phase modulation of the laser light by the hologram;
• and
• performing a focusing of focusing the laser light after the phase modulation, wherein
• in the control, the spatial light modulator presents the hologram for focusing the laser light after the phase modulation on a plurality of irradiation points in a processing object by the focusing, and
• at least one of a shape and a size of a processing region defined by the plurality of irradiation points in a first plane intersecting an optical axis of the laser light after the phase modulation with which the processing object is irradiated and a processing region defined by the plurality of irradiation points in a second plane intersecting the optical axis and separated from the first plane in a direction of the optical axis is set different from each other, and wherein
• in the control, when the hologram is changed, the spatial light modulator presents a hologram with which a light intensity of the laser light is less than a processing threshold value at any portion in the processing object during a period from erasing a certain hologram to presenting another hologram.