Low-aberration deflectors for use in charged-particle-beam optical systems, and methods for fabricating such deflectors

Abstract

Deflectors are disclosed that are suitable for use in various charged-particle-beam (CPB) optical systems as used, for example, in CPB microlithography systems. The deflectors produce a strong magnetic beam-deflecting field when energized with a relatively small electrical current. The beam-deflecting field thus produced is stable with respect to temperature changes, is little affected by eddy currents, and exhibits low aberration caused by manufacturing tolerances of the coil and core. In an exemplary method for manufacturing such a deflector, a magnetic-tape laminate is used as the core. Also, high-precision positioning of the coil and the magnetic-tape laminate is performed using photolithography and electrocasting. Positioning of the magnetic-tape laminate can be performed using a resist pattern formed by photolithography.

1 . A toroidal deflector for use in a charged-particle-beam optical system, comprising: 
 an annular core surrounding an optical axis, wherein the core comprises a laminate of magnetic tape; and    multiple coils positioned radially around the annular core, the coils being individually electrically energizable to produce a deflecting magnetic field.    
     
     
         2 . The deflector of  claim 1 , wherein the coils are positioned at substantially equi-angular intervals from one another around the annular core.  
     
     
         3 . The deflector of  claim 1 , wherein the magnetic tape comprises a foil of magnetic metal.  
     
     
         4 . The deflector of  claim 1 , wherein the magnetic tape has a first end and a second end, the deflector further comprising: 
 a first power lead coupled to the first end; and    a second power lead coupled to the second end, wherein the first and the second power leads are electrically connectable to a power supply so as to cause the annular core to generate a lens field superposed on the deflecting magnetic field.    
     
     
         5 . The deflector of  claim 4 , configured as a MOL lens-deflector unit.  
     
     
         6 . A vane-yoke deflector for use in a charged-particle-beam optical system, the deflector including multiple vanes radially positioned around an optical axis of the deflector, each vane comprising: 
 a planar substrate having first and second major surfaces;    an electrically energizable first coil affixed to the first major surface in a first substantially spiral pattern, the first coil defining a respective coil interior; and    a first core affixed to the first major surface and positioned in an interior of the first coil, the first core comprising a laminate of magnetic tape.    
     
     
         7 . The deflector of  claim 6 , further comprising: 
 an electrically energizable second coil affixed to the second major surface in a second substantially spiral pattern that mirrors the first substantially spiral pattern, the second coil defining a respective coil interior and being electrically connected to the first coil at mutual termini of the first and second coils; and    a second core affixed to the second major surface and positioned in an interior of the second coil, the second core comprising a laminate of magnetic tape.    
     
     
         8 . The deflector of  claim 6 , wherein the magnetic tape comprises a foil of magnetic metal.  
     
     
         9 . The deflector of  claim 6 , wherein the first core is positioned in the interior of the first coil by multiple positioning features on the first major surface and disposed so as to be situated on the periphery of the first core after the first core is affixed to the first major surface.  
     
     
         10 . The deflector of  claim 9 , wherein the positioning features are electrically insulated from the first core.  
     
     
         11 . The deflector of  claim 6 , wherein the first core has a thickness that changes with radial distance from the optical axis.  
     
     
         12 . The deflector of  claim 11 , wherein the thickness of the first core increases with increasing radial distance from the optical axis.  
     
     
         13 . The deflector of  claim 6 , wherein the first core is divided into multiple respective core segments that are electrically insulated from one another.  
     
     
         14 . A saddle deflector for use in a charged-particle-beam optical system, comprising: 
 a cylindrical substrate having an outer surface and an inner surface;    an electrically energizable coil first affixed in a spiral pattern to the outer surface, the first coil defining a respective coil interior; and    a first core affixed to the outer surface in the coil interior, the first core comprising a laminate of magnetic tape.    
     
     
         15 . The deflector of  claim 14 , wherein the magnetic tape comprises a foil of a magnetic metal.  
     
     
         16 . The deflector of  claim 14 , wherein the first core is divided into multiple respective core segments that are electrically insulated from one another.  
     
     
         17 . The deflector of  claim 16 , further comprising: 
 an electrically energizable second coil affixed in a spiral pattern to the outer surface at a location radially opposite the first coil, the second coil defining a coil interior; and    a second core affixed to the outer surface in the coil interior of the second coil, the second core comprising a laminate of magnetic tape.    
     
     
         18 . A saddle deflector for use in a charged-particle-beam optical system, comprising: 
 a cylindrical substrate having an outer surface, an inner surface, and defining multiple through-holes each defining a respective aperture extending between the outer surface and the inner surface;    first and second outer electrically energizable coils affixed to the outer surface at respective locations radially opposite each other, wherein the respective spiral patterns mirror each other, and each first and second outer coil defines a respective outer coil interior; and    first and second inner electrically energizable coils affixed to the inner surface at respective locations radially opposite each other, wherein the respective spiral patterns mirror each other and each first and second inner coil defines a respective coil interior, wherein a respective end of each inner coil is electrically connected to a respective end of each outer coil through a respective through-hole.    
     
     
         19 . The deflector of  claim 18 , wherein the first and second inner coils are axially oriented ninety degrees relative to the first and second outer coils.  
     
     
         20 . The deflector of  claim 18 , wherein the first and second inner coils are axially aligned with the first and second outer coils.  
     
     
         21 . The deflector of  claim 18 , further comprising a respective core affixed to each outer coil interior, each core comprising a laminate of magnetic tape.  
     
     
         22 . The deflector of  claim 21 , wherein the magnetic tape comprises foil of a magnetic metal.  
     
     
         23 . The deflector of  claim 20 , wherein each core is divided into multiple respective core portions that are electrically insulated from one another.  
     
     
         24 . A biaxial saddle deflector for use in a charged-particle-beam optical system, comprising: 
 a first saddle deflector as recited in  claim 14;  and    a second saddle deflector substantially similar to the first saddle deflector, but having an outer diameter smaller than an inside diameter of the first saddle deflector, the second saddle deflector being inserted coaxially inside the first saddle deflector.    
     
     
         25 . The biaxial saddle deflector of  claim 24 , wherein the first saddle deflector and the second saddle deflector are axially oriented ninety degrees relative to one another.  
     
     
         26 . The biaxial saddle deflector of  claim 24 , wherein: 
 the first saddle deflector further comprises a first flange;    the second saddle deflector further comprises a second flange; and    the first and second flanges are configured to position the second saddle deflector in an orientation relative to the first saddle deflector, wherein the second saddle deflector is inserted coaxially inside the first saddle deflector.