Multi-column scanning electron microscopy system

Abstract

A multi-column scanning electron microscopy (SEM) system includes a column assembly, where the column assembly includes a first substrate array assembly and at least a second substrate array assembly. The system also includes a source assembly, the source assembly including two or more illumination sources configured to generate two or more electron beams and two or more sets of a plurality of positioners configured to adjust a position of a particular illumination source of the two or more illumination sources in a plurality of directions. The system also includes a stage configured to secure a sample, where the column assembly directs at least a portion of the two or more electron beams onto a portion of the sample.

What is claimed: 
     
         1 . A multi-column scanning electron microscopy (SEM) system comprising:
 a column assembly comprising:
 a first substrate array assembly; and 
 at least a second substrate array assembly, 
 wherein a substrate array of at least one of the first substrate array assembly or the at least a second substrate array assembly includes:
 a composite substrate formed from a plurality of substrate layers, wherein the composite substrate includes a hole for each of the two or more electron beams; 
 a plurality of electrical components embedded within the plurality of substrate layers; 
 at least one ground bonding pad coupled to at least one of a top surface or a bottom surface of the composite substrate; 
 at least one signal bonding pad coupled to at least one of the top surface or the bottom surface of the composite substrate; and 
 a plurality of column electron-optical elements, wherein the plurality of column electron-optical elements are bonded to the composite substrate over the plurality of holes in the composite substrate, wherein each of the plurality of column electron-optical elements are bonded to a particular ground bonding pad and a particular signal bonding pad coupled to at least one of the top surface or the bottom surface of the composite substrate; 
 
   a source assembly comprising:
 two or more electron beam sources configured to generate two or more electron beams, wherein each of the two or more electron beam sources is configured to generate an electron beam of the two or more electron beams; and 
 two or more sets of a plurality of positioners, wherein each set of the plurality of positioners is configured to adjust a position of a particular electron beam source of the two or more electron beam sources in a plurality of directions; and 
   a stage configured to secure a sample, wherein the column assembly is configured to direct at least a portion of the two or more electron beams onto a portion of the sample.   
     
     
         2 . The system in  claim 1 , wherein the source assembly further comprises:
 two or more sets of source electron-optical elements, wherein each of the two or more sets of source electron-optical elements is configured to direct at least a portion of an electron beam of the two or more electron beams through the column assembly.   
     
     
         3 . The system in  claim 1 , further comprising:
 two or more detector assemblies, wherein the two or more detector assemblies are positioned to detect electrons emitted or scattered from the surface of the sample.   
     
     
         4 . The system in  claim 3 , wherein the two or more detector assemblies are positioned within the column assembly. 
     
     
         5 . The system in  claim 1 , wherein each of the two or more electron beam sources comprises:
 at least one of a Schottky emitter device, a carbon nanotube (CNT) emitter, a nanostructured carbon film emitter, or a Muller-type emitter.   
     
     
         6 . The system in  claim 1 , wherein at least one of the first substrate array assembly or the at least a second substrate array assembly includes two or more substrate arrays, wherein at least one metal shield is positioned between the two or more substrate arrays. 
     
     
         7 . The system in  claim 1 , wherein the first substrate array assembly is arranged in a first substrate array stack and mounted in a first frame, wherein the at least a second substrate array assembly is arranged in at least a second substrate array stack and mounted in at least a second frame, wherein the first frame and the at least a second frame are coupled. 
     
     
         8 . The system in  claim 7 , wherein at least one of arranging the first substrate array assembly, arranging the second substrate array stack, or coupling the first frame and the at least a second frame includes aligning to compensate for at least one of an offset distance in an x-direction, an offset distance in a y-direction, or an offset rotation angle. 
     
     
         9 . The system in  claim 1 , wherein the first substrate array assembly is arranged in a first bonded substrate array stack, wherein the at least a second substrate array assembly is arranged in at least a second bonded substrate array stack, wherein the first bonded substrate array stack and the at least a second bonded substrate array stack are bonded. 
     
     
         10 . The system in  claim 9 , wherein at least one of arranging the first substrate array assembly, arranging the at least a second substrate array, or bonding the first bonded substrate array stack and the at least a second bonded substrate array stack includes aligning to compensate for at least one of an offset distance in an x-direction, an offset distance in a y-direction, or an offset rotation angle. 
     
     
         11 . The system in  claim 1 , wherein the first substrate array assembly is arranged in a first substrate array stack and mounted in a frame, wherein the at least a second substrate array assembly is arranged in at least a second substrate array stack and mounted in the same frame. 
     
     
         12 . The system in  claim 11 , wherein at least one of arranging the first substrate array assembly or arranging the second substrate array stack includes aligning to compensate for at least one of an offset distance in an x-direction, an offset distance in a y-direction, or an offset rotation angle. 
     
     
         13 . The system in  claim 1 , wherein each set of the plurality of positioners is configured to adjust a position of a particular illumination source in a plurality of directions, the plurality of directions including at least one of an x-direction, a y-direction, or a z-direction. 
     
     
         14 . The system in  claim 1 , wherein the plurality of electrical components embedded within the plurality of substrate layers include at least one of one or more ground traces, one or more signal traces, one or more ground vias, or one or more signal vias. 
     
     
         15 . The system in  claim 14 , wherein at least one of the one or more ground traces, the one or more ground vias, the one or more signal traces, or the one or more signal vias are embedded in the plurality of substrate layers prior to forming the composite substrate. 
     
     
         16 . The system in  claim 14 , wherein the one or more ground traces are electrically coupled to the at least one ground bonding pad with the one or more ground vias. 
     
     
         17 . The system in  claim 14 , wherein the one or more signal traces are electrically coupled to the at least one signal bonding pad with the one or more signal vias. 
     
     
         18 . A method comprising:
 forming a plurality of substrate arrays, wherein forming the substrate array of the plurality of substrate array includes:
 embedding one or more components within a plurality of substrate layers; 
 forming a composite substrate from the plurality of substrate layers; 
 boring a plurality of holes in the composite substrate; 
 coupling at least one ground bonding pad to at least one of a top surface or a bottom surface of the composite substrate; 
 coupling at least one signal bonding pad to at least one of the top surface or the bottom surface of the composite substrate; and 
 bonding a plurality of column electron-optical elements to a particular ground bonding pad and a particular signal bonding pad coupled to at least one of the top surface or the bottom surface of the composite substrate, wherein each of the plurality of column electron-optical elements are positioned over the plurality of holes in the composite substrate; 
   sorting the plurality of substrate arrays into a first substrate array assembly and at least a second substrate array assembly; and   forming a column assembly from the first substrate array assembly and the at least a second substrate array assembly.   
     
     
         19 . The method in  claim 18 , wherein at least some of the plurality of column electron-optical elements are partially fabricated via a first set of fabrication processes prior to bonding the at least some of the plurality of column electron-optical elements to a particular ground bonding pad and a particular signal bonding pad, wherein the at least some of the plurality of column electron-optical elements are fully fabricated via a second set of fabrication processes after bonding the at least some of the plurality of column electron-optical elements to the particular ground bonding pad and the particular signal bonding pad. 
     
     
         20 . The method in  claim 19 , wherein the first set of fabrication processes includes:
 boring a hole based on at least one critical tolerance in the at least some of the plurality of column electron-optical elements; and   cutting a plurality of slots in the at least some of the plurality of column electron-optical elements, wherein the plurality of slots includes a first slot and at least a second slot, wherein the first slot and the at least a second slot pass through a portion of the hole, wherein the first slot and the at least a second slot do not extend to the edge of the at least some of the plurality of column electron-optical elements.   
     
     
         21 . The method in  claim 20 , wherein the at least one critical tolerance includes at least one of a bore size or a bore shape. 
     
     
         22 . The method in  claim 20 , wherein the second set of fabrication processes includes:
 cutting the plurality of slots to extend to the edge of the at least some of the plurality of column electron-optical elements.