System and method for laser processing at non-constant velocities

Abstract

A method is disclosed for on-the-fly processing at least one structure of a group of structures with a pulsed laser output, The method includes the steps of relatively positioning the group of structures and the pulsed laser output axis with non-constant velocity, and applying the pulsed laser output to the at least one structure of the group of structures during the step of relatively positioning the group of structures and the pulsed laser output axis with non-constant velocity.

1 .- 32 . (canceled) 
     
     
         33 . A method of on-the-fly laser processing first and second structures of respective first and second groups of structures on a moving stage with a pulsed laser output along a pulsed laser output axis, each structure having a respective optimal processing time, said method comprising the steps of:
 relatively positioning the first and second structures and the pulsed laser output axis with respective first and second velocities, wherein the first and second velocities are different velocities; and   applying the pulsed laser output to the first and second structures during the step of relatively positioning the first and second structures and the pulsed laser output axis with the respective first and second velocities by selecting one or more laser pulses from a laser that is pulsed at a constant repetition rate that is not synchronized with relatively positioning at least one of the first or second structures and the pulsed laser output axis, such that laser processing of said at least one structure is performed during at least one time interval that comprises the at least one respective optimal processing time and a pulse-to-pulse time between sequential constant repetition rate laser pulses, wherein a distance that is characterized by a product of the at least one time interval and a relative positioning velocity at the optimal processing time is within an acceptable position enor between the pulsed laser output axis and the at least one structure of the first and second structures.   
     
     
         34 . The method as claimed in  claim 33 , wherein the pulsed laser output is provided by selecting pulses of a mode locked laser during the at least one time interval, each time interval corresponding to a position of said at least one structure of the first and second structures. 
     
     
         35 . A method of laser processing selected structures in an array of structures carried on a stage comprising:
 providing a pulsed laser output by pulsing a laser with a substantially constant pulse to pulse period.   moving the structures at a velocity relative to the pulsed laser output, wherein the distance between adjacent structures divided by the velocity comprises a period that is not synchronized with the pulse to pulse period;   selecting pulses from the pulsed laser output corresponding to respective selected structures, and   applying the selected pulses to the selected structures with acceptable position errors between the selected pulses and respective selected structures.   
     
     
         36 . The method as claimed in  claim 35 , wherein the pulse to pulse period times the velocity comprises a distance less than an acceptable laser pulse to structure positioning error 
     
     
         37 . The method as claimed in  claim 35 , wherein selecting comprises down counting from a higher pulse repetition rate. 
     
     
         38 . The method as claimed in  claim 35 , wherein the pulsed laser output comprises an amplified seed laser output. 
     
     
         39 . The method as claimed in  claim 35 , wherein moving the structures comprises moving according to an acceleration profile, the acceleration profile comprising at least first and second velocities. 
     
     
         40 . The method as claimed in  claim 39 , wherein one of the first and second velocities is a reduced velocity near the end of travel of a stage. 
     
     
         41 . The method as claimed in  claim 35 , wherein the velocity is selected from a continuous range of velocities. 
     
     
         42 . The method as claimed in  claim 35 , wherein applying further comprises deflecting the laser output axis with a beam deflector. 
     
     
         43 . The method as claimed in  claim 35 , further comprising planning a trajectory with at least one commanded stage velocity set within a continuous range of velocities. 
     
     
         44 . The method as claimed in  claim 35 , wherein selecting pulses comprises selecting a group of pulses applied to one structure, wherein for each pulse a distance that is characterized by a product of the at least one time interval and a relative positioning velocity at the optimal processing time is within an acceptable position error between the pulsed laser output axis and the at least one structure of the group of structures. 
     
     
         45 . A laser-based semiconductor processing system comprising:
 a laser configured to pulse at a substantially constant rate, the rate characterized by a pulse to pulse period to provide a pulsed laser output,   means for positioning structures relative to the pulsed laser output in a plane at velocities within a continuous range of velocities,   means for selecting one or more pulses from the pulsed laser output to irradiate respective structures, and   a system controller configured to receive target structure coordinates, to initiate movement of the structures at one or more velocities in a continuous range of velocities along a trajectory for processing target structures, and to send pulse selecting signals to the pulse selecting means when positional error between each selected pulse of the pulsed laser output and a target structure is below a predetermined error limit,   wherein the laser pulse to pulse period is unsynchronized with respect to the at least one velocity and the positions of the moving structures.   
     
     
         46 . The system as claimed in  claim 45 , wherein means for positioning farther comprises beam deflecting means for combined relative positioning. 
     
     
         47 . The system as claimed in  claim 45 , where the structures are uniformly spaced apart structures. 
     
     
         48 . The system as claimed in  claim 45 , wherein the laser comprises a mode-locked laser. 
     
     
         49 . The system as claimed in  claim 45 , wherein the velocities comprise non-continuous velocities. 
     
     
         50 . The system as claimed in  claim 45 , wherein the continuous range of velocities is 50-200 mm/s. 
     
     
         51 . The system as claimed in  claim 45 , wherein means for positioning further comprises a multi-spot beam positioning system. 
     
     
         52 . The system as claimed in  claim 45 , wherein means for positioning further comprises a multi-path beam positioning system.