Laser working method, laser working apparatus, and its manufacturing method

A laser working method including the steps of:

• irradiating a plate-shaped object to be processed with a laser light;
• and
• locating a converging point of the laser light within the object so as to form a modified region serving as a starting point for cutting along a line to cut the object, wherein
• a reflection spatial light modulator, which modulates the laser light, a converging optical system, which converges the laser light modulated by the reflection spatial light modulator inside the object, and an adjustment optical system, which has a first optical element and a second optical element functioning as lenses and located on the optical path between the reflection spatial light modulator and the converging optical system are prepared,
• disposing the first optical element and the second optical element so as to matching the wavefront form at the reflection spatial light modulator to the wavefront form at the converging optical system, and the first optical element and the second optical element become a double telecentric optical system,
• at the time of forming the modified region, the laser light is modulated by a reflection spatial light modulator such that aberration of the laser light occurs at a position on which a converging point of the laser light is located inside the object becomes a predetermined aberration or less.

A laser working method comprising the steps of:

• irradiating a plate-shaped object to be processed with a laser light;
• and
• locating a converging point of the laser light within the object so as to form a modified region serving as a starting point for cutting along a line to cut the object, wherein
• a reflection spatial light modulator, which modulates the laser light, converging optical system, which converges the laser light modulated by the reflection spatial light modulator inside the object, and an adjustment optical system, which has a first optical element and a second optical element functioning as lenses and located on the optical path between the reflection spatial light modulator and the converging optical system are prepared,
• disposing the first optical element and the second optical element so as to matching the wavefront form at the reflection spatial light modulator to the wavefront form at the converging optical system ,and the first optical element and the second optical element become a double telecentric optical system,
• at the time of forming the modified region, the laser light is modulated by a reflection spatial light modulator such that a wavefront of the laser light becomes a predetermined wavefront inside the object.

A laser working apparatus that irradiates a plate-shaped object to be processed with a laser light while locating a converging point within the object, so as to form a modified region serving as a starting point for cutting along a line to cut the object, the laser working apparatus comprising:

• a supporting base supporting the object;
• a laser light source emitting the laser light;
• a reflection spatial light modulator modulating the laser light emitted from the laser light source;
• a converging optical system converging the laser light modulated by the reflection spatial light modulator, inside the object supported by the supporting base;
• an adjustment optical system that has a first optical element and a second optical element functioning as lenses and located on the optical path between the reflection spatial light modulator and the converging optical system, and
• a controller that, at the time of forming the modified region, controls at least one of the supporting base and the converging optical system such that a converging point of the laser light is located at a predetermined distance from a laser light entrance surface of the object and the converging point of the laser light is relatively moved along the line, and the laser light is modulated by a reflection spatial light modulator such that aberration of the laser light occurs at a position on which a converging point of the laser light is located inside the object becomes a predetermined aberration or less, wherein
• the first optical element and the second optical element are disposed so as to match the wavefront form at the reflection spatial light modulator to the wavefront form at the converging optical system, and the first optical element and the second optical element become a double telecentric optical system.

A laser working apparatus that irradiates a plate-shaped object to be processed with a laser light while locating a converging point within the object, so as to form a modified region serving as a starting point for cutting along a line to cut the object, the laser working apparatus comprising:

• a supporting base supporting the object;
• a laser light source emitting the laser light;
• a reflection spatial light modulator modulating the laser light emitted from the laser light source;
• a converging optical system converging the laser light modulated by the reflection spatial light modulator, inside the object supported by the supporting base;
• an adjustment optical system that has a first optical element and a second optical element functioning as lenses and located on the optical path between the reflection spatial light modulator and the converging optical system, and
• a controller that, at the time of forming the modified region, controls at least one of the supporting base and the converging optical system such that a converging point of the laser light is located at a predetermined distance from a laser light entrance surface of the object and the converging point of the laser light is relatively moved along the line, and controls the reflection spatial light modulator such that a wavefront of the laser light becomes a predetermined wavefront inside the object, wherein
• the first optical element and the second optical element are disposed so as to match the wavefront form at the reflection spatial light modulator to the wavefront form at the converging optical system, and the first optical element and the second optical element become a double telecentric optical system.