Hamamatsu-photonics K.k.

Koji Kuno

Tatsuya Suzuki

Kazuhiro Atsumi

Masayoshi Kusunoki

Kenshi Fukumitsu

Tetsuya Osajima

Fumitsugu Fukuyo

Masayoshi Kumagai

Takashi Inoue

Makoto Nakano

Takeshi Sakamoto

Kenichi Muramatsu

Norio Kurita

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

An object is irradiated with a laser light modulated by a reflection type spatial light modulator such that aberration of the laser light converged inside the object becomes a predetermined aberration or less. Therefore, aberration of the laser light generated at a position on which a converging point of the laser light is located is made as small as possible, to enhance the energy density of the laser light at that position, which makes it possible to form a modified region with a high function as a starting point for cutting. In addition, because the reflection type spatial light modulator is used, it is possible to improve the utilization efficiency of the laser light as compared with a transmissive type spatial light modulator.

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

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 laser processing apparatus comprises a converging lensfor converging processing laser light and rangefinding laser light Ltoward a wafer, an actuator for actuating the lens, a shaping optical systemfor adding astigmatism to reflected light Lof the rangefinding laser light, a quadrant photodiodefor receiving the reflected light Land outputting voltage values corresponding to its light quantities, and a controller for regulating the actuator, and positions a converging point Pof the rangefinding laser light Lbetween a focal point Pof the lens and the lens, so as to make it possible to form a modified region at a position deeper from the front face, thereby suppressing adverse effects due to the reflected light L. The control is based on an arithmetic value subjected to a division by a sum of the voltage values, so as to prevent the arithmetic value from being changed by the quantity of reflected light.

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Hamamatsu, Japan

Koji Kuno