Microlens arrays for parallel micropatterning

Abstract

Disclosed herein are systems and methods for using microlens arrays for parallel micropatterning of features. In some embodiments, a system includes a laser that emits a laser beam, a beam homogenizer configured to shape the laser beam into a shaped laser beam having a beam profile, and a lenslet array. The beam homogenizer shapes the laser beam such that at least a portion of the beam profile is substantially uniform in power. The lenslets of the lenslet array have the same shape and each receive a respective portion of the shaped laser beam to output a plurality of laser sub-beams. The plurality of laser sub-beams can be directed toward one or more layers of material to generate or modify a plurality of features on the one or more layers in parallel.

What is claimed is: 
     
         1 . A method comprising:
 emitting a laser beam;   passing the laser beam through a beam homogenizer to form a shaped laser beam having a beam profile, wherein at least a portion of the beam profile is substantially uniform in power;   providing the shaped laser beam to a lenslet array that includes a plurality of lenslets, wherein each lenslet of the plurality of lenslets has a same shape and receives a respective portion of the shaped laser beam, the respective portion of the shaped laser beam corresponding to the at least a portion of the beam profile that is substantially uniform in power;   generating a plurality of laser sub-beams using the lenslet array, each laser sub-beam of the plurality of laser sub-beams being generated by a corresponding lenslet based on the respective portion of the shaped laser beam received by the lenslet; and   directing the plurality of laser sub-beams toward one or more layers of material to generate or modify a plurality of features on the one or more layers in parallel.   
     
     
         2 . The method of  claim 1 , wherein directing the plurality of laser sub-beams toward the one or more layers to generate or modify the plurality of features on the one or more layers in parallel comprises:
 moving at least one of the lenslet array or the one or more layers such that a focal point of each lenslet of the plurality of lenslets is scanned in a scanning pattern.   
     
     
         3 . The method of  claim 2 , wherein the scanning pattern comprises a plurality of concentric circles. 
     
     
         4 . The method of  claim 2 , wherein the scanning pattern comprises a spiral. 
     
     
         5 . The method of  claim 2 , wherein the scanning pattern causes the plurality of laser sub-beams to shape the plurality of features into microlenses. 
     
     
         6 . The method of  claim 1 , wherein the plurality of features is formed by two-photon polymerization of a material in the one or more layers. 
     
     
         7 . The method of  claim 1 , wherein:
 the one or more layers includes a first layer and a second layer, and   each laser sub-beam generates or modifies a corresponding hole to form a plurality of holes, the plurality of holes extending through the first layer and exposing the second layer.   
     
     
         8 . The method of  claim 7 , wherein:
 the first layer corresponds to a wafer,   the second layer is a polymer layer in which a plurality of mesas is embedded,   the method further comprises injecting a plasma species through the plurality of holes to etch the polymer layer, and   the injecting of the plasma species is performed as part of forming an array of light-emitting diodes from the plurality of mesas.   
     
     
         9 . The method of  claim 7 , wherein:
 the first layer corresponds to a silicon substrate,   the second layer is a metal layer, and   the method further comprises performing metal-assisted chemical etching to etch portions of the silicon substrate that are in contact with the metal layer while leaving portions of the silicon substrate that were exposed by the plurality of holes unetched.   
     
     
         10 . The method of  claim 1 , wherein the laser beam is a pulsed laser beam, and wherein the beam profile of the shaped laser beam is a flat-top profile. 
     
     
         11 . A system comprising:
 a laser configured to emit a laser beam;   a beam homogenizer configured to shape the laser beam into a shaped laser beam having a beam profile, wherein at least a portion of the beam profile is substantially uniform in power; and   a lenslet array comprising a plurality of lenslets, wherein:
 each lenslet of the plurality of lenslets has a same shape and is configured to receive a respective portion of the shaped laser beam, the respective portion of the shaped laser beam corresponding to the at least a portion of the beam profile that is substantially uniform in power, and 
 each lenslet of the plurality of lenslets is configured to generate a corresponding laser sub-beam based on the respective portion of the shaped laser beam received by the lenslet, such that the lenslet array outputs a plurality of laser sub-beams in parallel. 
   
     
     
         12 . The system of  claim 11 , wherein the system is configured to scan a focal point of each lenslet of the plurality of lenslets according to a scanning pattern, based on movement of the lenslet array relative to one or more layers of material toward which the plurality of laser sub-beams is directed. 
     
     
         13 . The system of  claim 11 , wherein the laser beam is a pulsed laser beam, and wherein the beam profile of the shaped laser beam is a flat-top profile. 
     
     
         14 . The system of  claim 11 , further comprising:
 a beam confiner arranged between the laser and the beam homogenizer.   
     
     
         15 . The system of  claim 14 , wherein the beam confiner is configured to collimate the laser beam. 
     
     
         16 . The system of  claim 14 , wherein the beam confiner is a cylindrical tube. 
     
     
         17 . The system of  claim 16 , wherein the beam confiner corresponds to a microscope objective without optical elements. 
     
     
         18 . The system of  claim 11 , wherein the lenslets are arranged in a hexagonal pattern. 
     
     
         19 . The system of  claim 11 , wherein the lenslet array is positioned on an exit window of the beam homogenizer. 
     
     
         20 . The system of  claim 19 , wherein the system is configured to move the beam homogenizer and the lenslet array together, along each axis of a three-axis coordinate system and while the laser beam is being emitted by the laser.