Abstract: A laser repair apparatus comprises a stage for a wafer to be mounted on, a laser beam source for emitting a laser beam, focus adjusting means for adjusting a focus of the laser beam, and focal point measuring means for measuring a focal point of the laser beam with respect to the wafer on the stage, and a system controller for controlling an overall operation of the laser repair apparatus. The focus adjusting means adjusts a focus with respect to each part to be repair-processed. The system controller sets a focal point at a prescribed position in the required part to be repair-processed as a reference focal point. In performing the repair processing at another position, a focal point is detected by the focal point measuring means. The system controller interrupts the repair processing when the focal point is outside an allowable range from the reference focal point.

Abstract: In a laser machining apparatus for performing a laser repair process on a semiconductor wafer, fuses are selectively melted based on the result of judging. A method for aligning a laser machining apparatus for applying a laser beam for laser machining, includes the steps of: detecting a position of a first specific point for alignment provided on an object-to-be-machined; computing a position of a second specific point for alignment other than the first specific point, based on a detected position of the first specific point; detecting a position of the second specific point; and comparing the computed position of the second specific point with the detected position of the second specific point. When the difference between both positions is above a preset threshold value, the laser machining is interrupted.