Semiconductor structure processing using multiple laterally spaced laser beam spots delivering multiple blows

Abstract

Methods and systems process a semiconductor substrate having a plurality of structures to be selectively irradiated with multiple laser beams. The structures are arranged in a plurality of substantially parallel rows extending in a generally lengthwise direction. The method generates a first laser beam that propagates along a first laser beam axis that intersects a first target location on or within the semiconductor substrate. The method also generates a second laser beam that propagates along a second laser beam axis that intersects a second target location on or within the semiconductor substrate. The second target location is offset from the first target location in a direction perpendicular to the lengthwise direction of the rows by some amount such that, when the first target location is a structure on a first row of structures, the second target location is a structure or between two adjacent structures on a second row distinct from the first row. The method moves the semiconductor substrate relative to the first and second laser axes in a direction approximately parallel to the rows of structures, so as to pass the first target location along the first row to irradiate for a first time selected structures in the first row, and so as to simultaneously pass the second target location along the second row to irradiate for a second time structures previously irradiated by the first laser beam during a previous pass of the first target location along the second row.

1 . A system for processing a semiconductor substrate having a plurality of structures to be selectively irradiated with multiple laser beams, the structures being arranged in a plurality of substantially parallel rows extending in a generally lengthwise direction, the system comprising:
 a means for generating a first laser beam that propagates along a first laser beam axis that intersects a first target location on or within the semiconductor substrate;   a means for generating a second laser beam that propagates along a second laser beam axis that intersects a second target location on or within the semiconductor substrate, the second target location being offset from the first target location in a direction perpendicular to the lengthwise direction of the rows by some amount such that, when the first target location is a structure on a first row of structures, the second target location is a structure or between two adjacent structures on a second row distinct from the first row; and   a means for moving the semiconductor substrate relative to the first and second laser axes in a direction approximately parallel to the rows of structures, so as to pass the first target location along the first row to irradiate for a first time selected structures in the first row, and so as to simultaneously pass the second target location along the second row to irradiate for a second time structures previously irradiated by the first laser beam during a previous pass of the first target location along the second row.   
   
   
       2 . A system for processing a semiconductor substrate having a plurality of structures to be selectively irradiated with multiple laser beams, the structures being arranged in a plurality of substantially parallel rows extending in a generally lengthwise direction, the system comprising:
 a laser source producing at least a first laser beam and a second laser beam;   a first laser beam propagation path going from the laser source to the semiconductor substrate and having a first laser beam axis that intersects a first target location on or within the semiconductor substrate;   a second laser beam propagation path going from the laser source to the semiconductor substrate and having a second laser beam axis that intersects a second target location on or within the semiconductor substrate, the second target location being offset from the first target location in a direction perpendicular to the lengthwise direction of the rows by some amount such that, when the first target location is a structure on a first row of structures, the second target location is a structure or between two adjacent structures on a second row distinct from the first row; and   a motion stage that moves the semiconductor substrate relative to the first and second laser axes in a direction approximately parallel to the rows of structures, so as to pass the first target location along the first row to irradiate for a first time selected structures in the first row, and so as to simultaneously pass the second target location along the second row to irradiate for a second time structures previously irradiated by the first laser beam during a previous pass of the first target location along the second row.   
   
   
       3 . The system of  claim 2 , wherein the laser source comprises:
 respective first and second lasers.   
   
   
       4 . The system of  claim 2 , wherein the laser source comprises:
 a laser; and   a beam splitter disposed in both the first and second laser beam propagation paths between the laser and the semiconductor substrate.   
   
   
       5 . The system of  claim 2 , further comprising:
 a first optical switch disposed in the first laser beam propagation path, the first optical switch capable of selectively passing or blocking the first laser beam from reaching the semiconductor substrate; and   a second optical switch disposed in the second laser beam propagation path, the second optical switch capable of selectively passing or blocking the second laser beam from reaching the semiconductor substrate.   
   
   
       6 . The system of  claim 5 , wherein the first and second optical switches are AOMs. 
   
   
       7 . The system of  claim 4 , further comprising:
 a controller connected to the first and second optical switches, the controller setting the states of the first and second optical switches so as to irradiate only selected structures.   
   
   
       8 . The system of  claim 2 , further comprising:
 a beam steering mechanism disposed in the first laser beam propagation path, whereby the first location can be adjusted.   
   
   
       9 . The system of  claim 2 , further comprising:
 a beam steering mechanism disposed in the second laser beam propagation path, whereby the second location can be adjusted.   
   
   
       10 . The system of  claim 2 , further comprising:
 a beam combiner disposed in both the first and the second laser beam propagation paths; and   a focus lens disposed in both the first and the second laser beam propagation paths between the beam combiner and the semiconductor substrate.   
   
   
       11 . The system of  claim 2 , further comprising:
 a first focus lens disposed in the first laser beam propagation path; and   a second focus lens disposed in the second laser beam propagation path.