Precision laser micromachining system for drilling holes

Abstract

A laser drilling system for drilling holes in a work piece with a laser. The system includes: a laser for creating a laser beam and directing the laser beam along an optical path; a mask having at least one aperture, the mask and the aperture being located in the optical path to cause the creation of a sub-beam; a lens for forming a reduced-size image of the sub-beam onto the work piece and a translation stage for moving the mask to change the position of the sub-beam on the work piece. The laser beam has a wavefront cross-section with an area greater than the size of the aperture and is incident upon the mask and the aperture to create the sub-beam.

1 . A laser drilling system for drilling holes in a work piece with a laser, said system comprising: 
 a laser for creating a laser beam and directing the laser beam along an optical path;    a mask having at least one aperture, the mask and the aperture being located in the optical path, wherein the laser beam has a wavefront cross-section with an area greater than the size of the aperture and is incident upon the mask and the aperture to cause the creation of a sub-beam;    a lens for forming a reduced-size image of the sub-beam onto the work piece;    a translation stage for moving the mask to change the position of the sub-beam on the work piece.    
   
   
       2 . The laser drilling system of  claim 1 , wherein the lens is a microscope objective lens.  
   
   
       3 . The laser drilling system of  claim 1  wherein the laser beam has a wavelength and the system further comprises a nonlinear optical medium for harmonic generation in the optical path to decrease the wavelength of the laser beam.  
   
   
       4 . The laser drilling system of  claim 3 , wherein the nonlinear optical medium for harmonic generation is a frequency doubler.  
   
   
       5 . The laser drilling system of  claim 4 , further comprising at least one frequency selective mirror in the optical path between the frequency doubler and the work piece for preferentially reflecting the decreased wavelength beam relative to light at the wavelength of the laser.  
   
   
       6 . The laser drilling system of  claim 1 , further comprising a shutter for controlling the propagation of the laser beam along the optical path and an attenuator for attenuating the laser beam when the shutter allows the laser beam to propagate.  
   
   
       7 . The laser drilling system of  claim 1 , further comprising a scan mirror in the optical path for homogenizing the laser beam before it is applied to the mask.  
   
   
       8 . The laser drilling system of  claim 1 , wherein the mask has at least two apertures for causing the creation of at least two parallel sub-beams.  
   
   
       9 . The laser drilling system of  claim 1 , further comprising an imaging system for viewing the work piece.  
   
   
       10 . The laser drilling system of  claim 1 , further comprising a circular polarizer for producing a circularly polarized laser beam.