System for semiconductor structure processing using multiple laser beam spots

Abstract

Methods and systems selectively irradiate structures on or within a semiconductor substrate using a plurality of pulsed laser beams. The structures are arranged in a row extending in a generally lengthwise direction. The method generates a first pulsed laser beam that propagates along a first laser beam axis that intersects the semiconductor substrate and a second pulsed laser beam that propagates along a second laser beam axis that intersects the semiconductor substrate. The method directs respective first and second pulses from the first and second pulsed laser beams onto distinct first and second structures in the row. The method moves the first and second laser beam axes relative to the semiconductor substrate substantially in unison in a direction substantially parallel to the lengthwise direction of the row.

1 . A system for selectively irradiating structures on or within a semiconductor substrate using a plurality of pulsed laser beams, the structures being substantially straight strip-shaped objects having a length and a substantially uniform width and depth, the structures being arranged in a row extending in a generally lengthwise direction that is transverse to a direction in which the object's lengths are measured, the system comprising:
 a means for generating a first pulsed laser beam that propagates along a first laser beam axis that intersects the semiconductor substrate;   a means for generating a second pulsed laser beam that propagates along a second laser beam axis that intersects the semiconductor substrate;   a means for directing respective first and second pulses from the first and second pulsed laser beams onto distinct first and second structures in the row,   wherein the first and second laser beam axes intersect the semiconductor substrate at respective first and second spots, and wherein the first and second spots are purposefully offset from each other by a deliberate amount in the direction in which the objects' length are measured; and   a means for moving the first and second laser beam axes relative to the semiconductor substrate substantially in unison in a direction substantially parallel to the lengthwise direction of the row.   
     
     
         2 . A system for selectively irradiating structures on or within a semiconductor substrate using a plurality of pulsed laser beams, the structures being substantially straight strip-shaped objects having a length and a substantially uniform width and depth, the structures being arranged in a row extending in a generally lengthwise direction that is transverse to a direction in which the object's lengths are measured, the system comprising:
 a laser source producing at least a first pulsed laser beam and a second pulsed laser beam;   a first laser beam propagation path, along which the first laser beam propagates toward the semiconductor substrate, the first laser beam propagation path having a first laser beam axis that intersects the semiconductor substrate at a first spot;   a second laser beam propagation path, along which the second laser beam propagates toward the semiconductor substrate, the second laser beam propagation path having a second laser beam axis that intersects the semiconductor substrate at a second spot, wherein the first spot and the second spot impinge upon distinct first and second structures in the row; and   a motion stage that moves the first and second laser beam axes relative to the semiconductor substrate substantially in unison in a direction substantially parallel to the lengthwise direction of the row, wherein the first and second spots are purposefully offset from each other by a deliberate amount in the direction in which the objects' length are measured.   
     
     
         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 5 , 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.   
     
     
         12 . The system of  claim 11 , wherein the first lens is operable to focus the first laser beam on or within the semiconductor substrate, wherein the second lens is operable to focus the second laser beam on or within the semiconductor substrate, wherein the second lens is different from the first lens, wherein the first laser beam does not propagate through the second focus lens, and wherein the second laser beam does not propagate through the first focus lens. 
     
     
         13 . The system of  claim 2 , wherein the semiconductor substrate comprises a number of dice having a substantially equal dice spacing between corresponding parts of adjacent dice, wherein the first and second spots are offset from one another by some amount in the lengthwise direction of the row, wherein said amount is equal to a non-zero integer multiple of said dice spacing. 
     
     
         14 . The system of  claim 2 , wherein a first size of the first laser spot is different from a second size of the second laser spot. 
     
     
         15 . The system of  claim 2 , wherein the first and second structures are nonadjacent. 
     
     
         16 . The system of  claim 2 , wherein more than one structure is positioned between the first and second structures. 
     
     
         17 . The system of  claim 2 , wherein the first and second spots are separated by a distance sufficient to avoid a deleterious concentration of energy being absorbed by the semiconductor substrate between the first and second spots. 
     
     
         18 . The system of  claim 2 , wherein the first and second pulsed laser beams have respective first and second sets of optical properties, and wherein the first and second sets have different properties. 
     
     
         19 . The system of  claim 2 , wherein the first and second structures comprise potential electrically conductive links, and irradiation of a link results in severing that link. 
     
     
         20 . The system of  claim 2 , wherein a trigger signal is employed to commence propagation of the first and second pulsed laser beams, the trigger signal responsive to a laser controller utilizing data of one or more desired target locations and of positions of more or more of the laser beam axes on the semiconductor substrate.