Patent ID: 7394476
Filing Date: 2008-07-01
Classification: B23K,H01L,H05K

Abstract:
1. A method of laser processing a 1D or 2D array of conductive links to remove one or more designated links of the array without damaging a substrate, adjacent non-designated links, or one or more functional layers or levels disposed between the conductive links and the substrate, the processing of the one or more designated links to occur with one or more laser pulses in a single pass operation controlled with a positioning subsystem of a laser-based, memory repair system, the positioning subsystem causing relative motion between the conductive links and one or more laser beam spots, the method comprising: obtaining information to identify the one or more designated links of the array and to identify one or more alignment targets about the one or more designated links, each of the one or more alignment targets having a predetermined location relative to the one or more designated links; scanning a measurement beam to obtain one or more signals representative of the locations of the one or more alignment targets and processing the one or more signals to determine the locations of the one or more alignment targets; predicting the locations of the one or more designated links relative to the one or more alignment targets, the step of predicting comprising relating the locations of the one or more alignment targets to the locations of the one or more designated links based on at least the pre-determined locations of the one or more alignment targets; planning and generating a trajectory to position the one or more laser beam spots relative to the one or more designated links so that the one or more designated links and the one or more laser beam spots substantially coincide at locations along centerlines of one or more pulsed laser beams, and also so that the one or more designated links and the one or more laser beam spots coincide at a time when the one or more laser pulses impinge the one or more designated links, the step of planning and generating comprising: producing a first motion profile corresponding to a first trajectory segment, the profile representative of approximately constant velocity of relative motion of the one or more designated links and the one or more laser beam spots generally along a row or column of the array, the motion occurring during a first specified time interval, or over a first specified distance, at which the one or more designated links are to be processed with the one or more laser pulses, and producing a second motion profile corresponding to a second trajectory segment, the second motion profile representative of an acceleration or deceleration during a second specified time interval, or over a second specified distance, at which the relative motion of the one or more designated links and the one or more laser beam spots is accelerated to achieve a predetermined velocity for processing with the one or more laser pulses; moving the one or more designated links relative to the one or more laser beam spots in accordance with the generated trajectory; generating the one or more laser pulses having at least one predetermined characteristic including a pulse width; selecting at least one frequency from an available range of frequencies so as to control at least one of a pulse location, number of pulses, and spatial spacing of the one or more pulses that are to impinge the one or more designated links, the, one or more designated links being within a region of the array and along at least one of one or more rows and one or more columns of the array; applying, during overlapping time periods, the at least one frequency to a multi-frequency deflector to produce as an output of the deflector the one or more pulsed laser beams having controlled deflection; focusing the one or more pulsed laser beams to form the one or more laser beam spots at the one or more designated link locations, wherein the step of focusing provides that the one or more laser beam spots are approximately diffraction limited, the steps of planning and generating a trajectory, selecting, applying, and focusing thereby precisely positioning the one or more laser beam spots at the one or more designated link locations; and irradiating the one or more designated links with the one or more laser beam spots wherein the one or more laser beam spots and the one or more designated links substantially coincide, the step of irradiating with the one or more laser beam spots providing for processing the one or more designated links during the single pass.