Efficient micro-machining apparatus and method employing multiple laser beams

Abstract

A laser beam switching system employs a laser coupled to a beam switching device that causes a laser beam to switch between first and second beam positioning heads such that while the first beam positioning head is directing the laser beam to process a workpiece target location, the second beam positioning head is moving to another target location and vice versa. A preferred beam switching device includes first and second AOMs positioned such that the laser beam passes through the AOMs without being deflected. When RF is applied to the first AOM, the laser beam is diffracted toward the first beam positioning head, and when RF is applied to the second AOM, the laser beam is diffracted toward the second beam positioning head.

1 . A system configured to direct a laser beam selectively in multiple beam propagation directions in a coordinated manner to achieve high-speed processing of material in different regions of a target specimen, comprising: 
 a laser source emitting a laser beam that includes a series of laser pulses;    a beam switching device receiving the series of laser pulses and, in response to a beam switching signal, directing first and second groups of the laser beam pulses to propagate along respective first and second beam axes;    a first positioning mechanism responding to a first control signal to provide relative movement of the first beam axis and the target specimen to selectively position the first beam axis at different first target regions of the target specimen and to process material in the first target regions of the target specimen;    a second positioning mechanism responding to a second control signal to provide relative movement of the second beam axis and the target specimen to selectively position the second beam axis at different second target regions of the target specimen to process material in the second target regions of the target specimen;    a controller producing the beam switching signal and the first and second control signals to effect coordinated system operation in first and second operational sequences;    the first operational sequence including the beam switching device directing the first group of laser beam pulses for incidence on a selected one of the first target regions, the first positioning mechanism providing the relative movement to enable the first group of laser pulses to process material in the selected first target region, and, during the material processing by the first group of laser pulses, the second positioning mechanism providing the relative movement to position the second beam axis to a selected one of the second target regions; and    the second operational sequence including the beam switching device directing the second group of laser beam pulses for incidence on the selected second target region, the second positioning mechanism providing the relative movement to enable the second group of laser pulses to process material in the selected second target region, and, during the material processing by the second group of laser pulses, the first positioning mechanism providing the relative movement to position the first beam axis from the selected first target region to a next selected one of the first target regions.    
   
   
       2 . A beam switching device that receives a laser beam and provides beam outputs that propagate selectively along different beam axes, comprising: 
 a controller producing a control drive signal in first and second states;    first and second optically associated acousto-optic modulators, the first acousto-optic modulator receiving an incoming laser beam, and the first and second acousto-optic modulators cooperating in response to the first and second states of the control device signal to produce respective first and second laser beam outputs propagating from the second acousto-optic modulator; and    the first laser beam output including a major component propagating along a first beam axis and a minor component propagating along a first minor component axis, and the second laser output including a major component propagating along a second beam axis that is angularly offset from the first beam axis and a minor component propagating along a second minor component axis that is substantially coincident to the first minor component axis.    
   
   
       3 . The beam switching device of  claim 2 , further comprising a beam blocker positioned to terminate the minor components propagating along the first and second minor component axes.  
   
   
       4 . The beam switching device of  claim 2 , in which: 
 the controller includes first and second RF drivers that are operationally associated with the respective first and second acousto-optic modulators; and    in the first state of the control drive signal, the first, RF driver causes the first acousto-optic modulator to pass the incoming laser beam as an undeflected beam incident on the second acousto-optic modulator and the second RF driver causes the second acousto-optic modulator to diffract the incident undeflected beam to form the major component to propagating along the first beam axis and the minor component propagating along the first minor component axis.    
   
   
       5 . The beam switching device of  claim 2 , in which: 
 the controller includes first and second RF drivers that are operationally associated with the respective first and second acousto-optic modulators; and    in the second state of the control drive signal, the second RF driver causes the second acousto-optic modulator to pass incident light as an undeflected beam and the first RF driver causes the first acousto-optic modulator to diffract the incoming laser beam to form the major component propagating along the second beam axis and the minor component to propagating along the second minor component axis.    
   
   
       6 . The beam switching device of  claim 2 , in which the first and second optically associated acousto-optic modulators are positioned in optical series.