LASER ANNEALING APPARATUS AND LASER ANNEALING METHOD

摘要

Metal is locally heated to a predetermined temperature within a predetermined time.;A laser annealing apparatus forms a line beam at a focusing position in a heatable area on a workpiece by an optical system, which has a long and narrow shape having a width of 0.5 μm all to 20 μm in the short direction and a long width of 6 μm to 200 μm in the length direction and has a depth of focus in the range of 2 μm to 4 μm, by using a semiconductor laser element that generates laser light, while moving a movable stage on which the workpiece has been mounted in an X direction and a Y direction; and selectively performs a heating step of performing laser annealing while controlling focusing and second laser power that has an output lower than the output of first laser power in the unheatable area on the workpiece.

主权项

1. A laser annealing apparatus that irradiates metal of a workpiece, on which heatable areas including metal disposed at arbitrary portions thereof and unheatable areas unsuitable for heating are disposed, with a long and narrow shape line beam to heat the metal and changes the grain size or bonding state of the metal, the laser annealing apparatus comprising:
a semiconductor laser element that generates laser light having a wavelength with high absorptance to metal; a lens that polarizes the laser light, which is generated from the semiconductor laser element, to collimated light; a beam splitter through which laser light emitted from the lens passes and which polarizes reflected light at an angle of 90° and emits the polarized light; an objective lens that has a high numerical aperture, and irradiates the workpiece with a line-shaped line beam that is formed by the concentration of the laser light emitted from the beam splitter; a movable stage on which the workpiece is mounted and which moves the workpiece in an X direction and a Y direction on a plane at an arbitrary speed; a laser controller that controls the laser emission of the semiconductor laser element; a focus detector that detects light reflected from the workpiece by the beam splitter and converts the reflected light into an electrical signal; an auto-focus controller that controls the focusing of the line beam on the basis of the electrical signal converted by the focus detector; a stage controller that controls the movement of the movable stage in the X direction and the Y direction; and a control means for controlling the laser controller, the auto-focus controller, and the stage controller, wherein while the stage controller moves the movable stage in the X direction and the Y direction, the laser controller forms a line beam at a focusing position on the workpiece in the heatable area on the workpiece by an optical system, which has a long and narrow shape having a width of 0.5 μm to 20 μm in the short direction and a long width of 6 μm to 200 μm in the length direction and has a depth of focus in the range of 2 μm to 4 μm, and a heating step of performing laser annealing while controlling the focusing by the auto-focus controller and second laser power that has an output lower than the output of the first laser power in the unheatable area on the workpiece are selectively performed by the laser controller.