Hamamatsu-photonics K.k.

Tatsuya Suzuki

Koji Kuno

Kazuhiro Atsumi

Masayoshi Kusunoki

Kenshi Fukumitsu

Fumitsugu Fukuyo

Tetsuya Osajima

Norio Kurita

Takeshi Sakamoto

Toshimitsu Wakuda

A laser processing method which can efficiently perform laser processing while minimizing the deviation of the converging point of a laser beam in end parts of an object to be processed is provided. This laser processing method comprises a preparatory step of holding a lens at an initial position set such that a converging point is located at a predetermined position within the object; a first processing step (Sand S) of emitting a first laser beam for processing while holding the lens at the initial position, and moving the lens and the ltd object relative to each other along a main surface so as to form a modified region in one end part of a line to cut; and a second processing step (Sand S) of releasing the lens from being held at the initial position after forming the modified region in the one end part of the line to cut, and then moving the lens and the object relative to each other along the main surface while adjusting the gap between the lens and the main surface after the release, so as to form the modified region.

Laser processing method and device

A laser processing method which can efficiently perform laser processing while minimizing the deviation of the converging point of a laser beam in end parts of an object to be processed is provided. This laser processing method comprises a preparatory step of holding a lens at an initial position set such that a converging point is located at a predetermined position within the object; a first processing step (Sand S) of emitting a first laser beam for processing while holding the lens at the initial position, and moving the lens and the object relative to each other along a main surface so as to form a modified region in one end part of a line to cut; and a second processing step (Sand S) of releasing the lens from being held at the initial position after forming the modified region in the one end part of the line to cut, and then moving the lens and the object relative to each other along the main surface while adjusting the gap between the lens and the main surface after the release, so as to form the modified region.

A laser processing method having a displacement acquiring step of acquiring a displacement between a point on the cutting line and one end of the cutting line in the object while irradiating the object with a second laser beam, converged by a lens, for measuring the displacement of a main surface of the object; and a position setting step of setting an initial position for holding the lens with respect to the main surface of the object according to the acquired displacement, and holding the lens at thus set initial position.

A converging point of processing laser light is made to accurately follow a laser light irradiation surface of an object to be processed. An object to be processedis irradiated with measuring laser light along a line to cut, astigmatism is added to a reflected light component of the measuring laser light reflected by a front faceof the objectirradiated with the measuring laser light, a displacement sensor signal corresponding to a converged light image of the reflected light component having the astigmatism added thereto is detected, and the displacement sensor signal is made to become a feedback reference value corresponding to the quantity of the reflected light component, so as to locate the converging point of the processing laser light at a predetermined position with respect to the front face. This allows tire converging point of the processing laser light to follow the front faceof the objectreliably and accurately even when an area exhibiting an extremely low reflectance to the measuring laser light exists in a part of the front faceand lowers the quantity of the reflected light component of the measuring laser light.

Laser working method

A laser processing method which can efficiently perform laser processing while minimizing the deviation of the converging point of a laser beam is provided. This laser processing method comprises a displacement acquiring step (Sto S) of irradiating an object to be processed with a rangefinding laser beam for measuring a displacement of a main surface of the object while converging the laser beam with a lens and acquiring the displacement of the main surface along a line to cut while detecting reflected light reflected by the main surface in response to the irradiation; and moves the processing objective lens and the object relative to each other along the main surface, while adjusting the gap between the processing objective lens and the surface according to the displacement acquired by the displacement acquiring step, thereby forming the modified region along the line to cut.

A modified region is accurately formed at a desirable position with respect to a laser light irradiation surface of an object to be processed. When an average difference &#x3b3; has a value exceeding a predetermined threshold during trace recording, a particle segment Z including a line segment S where the average difference &#x3b3; exceeds the predetermined threshold is defined. This determines that a particle exists on a line to cutand randomly reflects measuring laser light, whereby a segment where the presence of the particle affects a control signal in a line segment to cut is detected as the particle segment Z. Correcting the control signal in the particle segment Z inhibits a converging lens from moving more than necessary because of an error included in the signal value under the influence of the presence of the particle, thus allowing the converging point of the processing laser light to accurately follow a front face

Laser processing method for cutting planar object

A laser processing method which can reduce the chipping generated when a plate-like object to be processed formed with a modified region is turned into small pieces in steps other than its dividing step. In a part extending along a line to cut in an object to be processed, laser light is oscillated in a pulsing fashion in an intermediate portion including an effective part, and is continuously oscillated in one end portion and the other end portion on both sides of the intermediate portion. Since the laser light intensity becomes lower in continuous oscillation than in pulse oscillation, modified regions can be formed in the intermediate portion but not in one end portion and the other end portion. This keeps the modified regions from reaching the outer face of the substrate, thus making it possible to prevent particles from occurring when forming the modified regions.

Laser machining method

While a converging lensis relatively moved along a lineincluding a line to cut, measuring laser light Lis converged with the lenswhen the lensis positioned on a processing regionhaving an outer shape between an object to be processedand a frame, and a reflected light component of the laser light Lreflected by a front faceof the objectis detected. While keeping a substantially constant distance between the front faceand the lenssuch that a converging point P of processing laser light Lis positioned at a constant distance from the front faceaccording to the detection, the laser light Lis converged by the lens, so as to form a molten processed regionwithin the object

Laser processing method for forming a modified region in an object

An apparatus comprises a table, a source emitting polarized laser light, a source emitting laser light, a plate changing the polarization direction of the laser light, a plate splitting the laser light into a laser light having polarization in an X direction and a laser light component having polarization in a Y direction, a plate orienting the polarization direction of the laser light to the X direction, a lens converging the laser light components, a lens arranged in parallel with the lens along the X direction and converges the laser light component, a control section controlling a device such that a converging point of the laser light component is located at a predetermined position with reference to a front face by detecting a reflected light, and a control section moving the table along a line while making the X direction substantially coincide with the line.

Laser processing device

This laser processing method irradiates a substratewith laser light L while locating a light-converging point P within the substrate, so as to form a quality modified regionto become a starting point region for cutting within the substratealong a line to cut. Here, the laser light L is oscillated pulsewise along a desirable part RP in the line to cut, and continuously in a predetermined part RC in the line to cut. Consequently, the quality modified regionis formed within the substratealong the desirable part RP in the line to cut, whereas no quality modified regionis formed within the substratealong the predetermined part RC in the line to cut

Laser processing method

A shutter unit capable of preventing the scattering of the laser beam upon closing the optical path of the laser beam and capable of being miniaturized, and a laser processing device employing such a shutter unit. In a shutter unit, when the optical path of the laser beam L is opened, a rotating memberis rotated around an axis line &#x3b3;, and an openingis positioned on an optical axis &#x3b1; so as to pass the laser beam L therethrough. Meanwhile, when the optical path of the laser beam L is closed, the rotating memberis rotated and a reflective surfaceis positioned on the optical axis &#x3b1; so as to reflect the laser beam L. Here, since the reflected laser beam L is absorbed by an optical absorption member, it is possible to prevent the scattering of the laser beam L when the optical path of the laser beam L is closed. In addition, since the openingand reflective surfaceare both formed on the rotating memberwhich rotates around the axis line &#x3b3; that is substantially orthogonal to the optical axis &#x3b1;, it is possible to reduce the size of the shutter unit

Shutter unit and laser processing device using same

To provide a laser processing method which can highly accurately cut a planar object to be processed having an irregular surface as an entrance surface for processing laser light. This laser processing method irradiates a planar object to be processed with laser light while locating a light-converging point within the object, thereby forming modified regionstoto become a starting point region for cutting along lines to cut. The entrance surface r for the laser light in the object is an irregular surface. The lines to cutextend over a depressed area surface rand a protruded area surface rin the entrance surface r. The modified regionis formed inside by a predetermined distance from the depressed area surface r. At the time of irradiation with laser light along a parton the protruded area surface r, the light-converging point is located on the outside of the object. The modified regionis formed inside by a predetermined distance from the protruded area surface r. At the time of irradiation with laser light along a parton the depressed area surface r, the light-converging point is located on the outside of the object.

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Hamamatsu, Japan

Tatsuya Suzuki