A laser reflow method includes a preparation step of preparing a workpiece including a board and semiconductor chips that each have bumps formed on one surface thereof and are placed on the board with the bumps interposed therebetween and a laser beam irradiation step of irradiating the semiconductor chips with a laser beam from a side of another surface opposite to the one surface, thereby reflowing bumps formed within an irradiated area of the workpiece. In the laser beam irradiation step, the irradiation with the laser beam is carried out while an irradiation range of the laser beam is changed in stages from a region including an outer peripheral portion of the irradiated area toward a region including a central portion of the irradiated area.

A device for determining a focus position of a laser beam in a laser machining system has a first optical element which is designed to reflect a portion of the laser beam in order to uncouple a first sub-beam of the laser beam, a second optical element which is designed to reflect another portion of the laser beam in order to uncouple a second sub-beam of the laser beam substantially coaxially to the first sub-beam, a spatially-resolving sensor to which the first sub-beam and the second sub-beam can be directed, and an evaluation unit which is designed to determine a focus position of the laser beam on the basis of the first and second sub-beams hitting the spatially-resolving sensor.

A device for determining a focus position of a laser beam in a laser machining system has a first optical element which is designed to reflect a portion of the laser beam in order to uncouple a first sub-beam of the laser beam, a second optical element which is designed to reflect another portion of the laser beam in order to uncouple a second sub-beam of the laser beam substantially coaxially to the first sub-beam, a spatially-resolving sensor to which the first sub-beam and the second sub-beam can be directed, and an evaluation unit which is designed to determine a focus position of the laser beam on the basis of the first and second sub-beams hitting the spatially-resolving sensor.

The present invention discloses a varifocal laser processing system and method based on a variable light spot diffractive element. The system includes a laser device for generating a laser, a collimating lens for changing a light path and a diffractive optical element module for controlling light spot focal point distribution. The laser emitted by the laser device passes through the collimating lens to irradiate the diffractive optical element module, and the laser focused by the diffractive optical element module irradiates a to-be-processed workpiece; and the diffractive optical element module includes at least two DOE lenses oppositely distributed in an axial direction and a rotary actuator driving the DOE lenses to rotate. The rotary actuator drives at least one DOE lens to rotate with a central axis as a rotating center, thereby changing a position of a focal point generated after the laser is focused by the diffractive optical element module.

A method determines translational and/or rotational deviations between the measurement coordinate system of a measurement mirror scanner and the processing coordinate system of a processing mirror scanner. A measurement beam reflected at a workpiece returns on a path of an incident measurement beam and is captured by a spatially resolving measurement sensor to ascertain spatially resolving information of the workpiece. The reflected measurement beam, in a sensor image of the measurement sensor, is imaged onto a previously known image position. This is accomplished by ascertaining a focal position deviation of the processing beam by scanning with the processing beam, evaluating a laser power detected at grid points, fixing the processing mirror scanner, capturing spatially resolving height information of the pinhole diaphragm by the measurement sensor, and determining a translational deviation between the processing and measurement coordinate systems based on the deviation.

A method determines translational and/or rotational deviations between the measurement coordinate system of a measurement mirror scanner and the processing coordinate system of a processing mirror scanner. A measurement beam reflected at a workpiece returns on a path of an incident measurement beam and is captured by a spatially resolving measurement sensor to ascertain spatially resolving information of the workpiece. The reflected measurement beam, in a sensor image of the measurement sensor, is imaged onto a previously known image position. This is accomplished by ascertaining a focal position deviation of the processing beam by scanning with the processing beam, evaluating a laser power detected at grid points, fixing the processing mirror scanner, capturing spatially resolving height information of the pinhole diaphragm by the measurement sensor, and determining a translational deviation between the processing and measurement coordinate systems based on the deviation.

Device for production of three-dimensional components, namely a laser melting device or laser sintering device, in which a component is produced by successive solidifying of individual layers made from solidifiable construction material, by radiation, through melting of the construction material, wherein the dimensions and/or temperature of the melt area generated by a point-shaped or line-shaped energy input can be captured by a sensor device of a process monitoring system, and sensor values for evaluation of a component quality can by deduced therefrom, wherein the radiation created by the melt area and used for the generation of the sensor values passes through the scanner used for the melt energy input, and guided to the sensor device of the process monitoring system, wherein an optical focus tracking device is arranged in the radiation path used for generation of the sensor values between the scanner and the sensor device.

Device for production of three-dimensional components, namely a laser melting device or laser sintering device, in which a component is produced by successive solidifying of individual layers made from solidifiable construction material, by radiation, through melting of the construction material, wherein the dimensions and/or temperature of the melt area generated by a point-shaped or line-shaped energy input can be captured by a sensor device of a process monitoring system, and sensor values for evaluation of a component quality can by deduced therefrom, wherein the radiation created by the melt area and used for the generation of the sensor values passes through the scanner used for the melt energy input, and guided to the sensor device of the process monitoring system, wherein an optical focus tracking device is arranged in the radiation path used for generation of the sensor values between the scanner and the sensor device.

A beam adjusting unit of a laser processing apparatus that adjusts a beam diameter of a laser beam includes a first lens unit and a second lens unit that can move along an optical path of the laser beam and a first movement mechanism and a second movement mechanism that move the first lens unit and the second lens unit, respectively, along the optical path. A control unit includes a storing section that stores the beam diameter of the laser beam and positions of the first lens unit and the second lens unit corresponding to the beam diameter in advance, and causes the first movement mechanism and the second movement mechanism to be actuated to move the first lens unit and the second lens unit to positions corresponding to a predetermined beam diameter.

A processing head for a laser processing device adapted for processing a workpiece using laser radiation has: adjustable focusing optics to focus laser radiation in a focal spot having an adjustable distance from the processing head; an optical coherence tomograph to measure a distance between the processing head and the workpiece by measuring an optical interference between measuring light reflected by the workpiece and measuring light not reflected by the workpiece; a path length modulator that can change, synchronously with and dependent on a change of the focal spot distance from the processing head, an optical path length in an optical path along which measuring light propagates; a scanning device, which deflects the laser radiation in different directions; and a control device, which i) controls a focal length of the focusing optics in such a way that the focal spot is situated at a desired location on the workpiece, ii) receives, from the coherence tomograph, information representing the distance between the processing head and the workpiece, and iii) uses information received from the coherence tomograph for a continuous correction of a positioning of the focal spot on the workpiece.