Metal Lattice Production Method, Metal Lattice, X-Ray Imaging Device, and Intermediate Product for Metal Lattice

Abstract

Method for manufacturing a metal grating structure, wherein, after a concave part having an insulating layer on an inner surface thereof is formed in a silicon substrate, a portion of the insulating layer formed on a bottom part of the concave part is removed, and the silicon substrate at the bottom part of the concave part is etched to increase the surface area of the bottom part of the concave part as compared with a state before the etching, followed by filling the concave part with metal by an electroforming method.

1 . A method for manufacturing a metal grating structure, comprising:
 a resist layer forming step of forming a resist layer on a principal plane of a silicon substrate;   a patterning step of patterning the resist layer, and removing the patterned portion of the resist layer;   an etching step of etching the silicon substrate corresponding to the removed portion of the resist layer by a dry etching method, and forming a concave part of a predetermined depth;   an insulating layer forming step of forming an insulating layer on an inner surface of the concave part in the silicon substrate;   a removing/surface area increasing step of removing a portion of the insulating layer formed on a bottom part of the concave part, and etching the silicon substrate at the bottom part of the concave part to increase a surface area of the bottom part of the concave part as compared with a state before the etching; and   an electroforming step of applying a voltage to the silicon substrate to fill the concave part with metal by an electroforming method.   
     
     
         2 . The method for manufacturing a metal grating structure according to  claim 1 , wherein
 in the removing/surface area increasing step, the surface area of the bottom part of the concave part is increased as compared with the state before the etching by removing the portion of the insulating layer formed on the bottom part of the concave part, and by etching the silicon substrate at the bottom part of the concave part to such an extent that a side surface of the concave part has a tapered shape and a depth of the concave part is deeper than the predetermined depth.   
     
     
         3 . The method for manufacturing a metal grating structure according to  claim 1 , wherein
 in the removing/surface area increasing step, the surface area of the bottom part of the concave part is increased as compared with the state before the etching by removing the portion of the insulating layer formed on the bottom part of the concave part, and by etching the silicon substrate at the bottom part of the concave part to such an extent that a side surface of the concave part has a curved surface shape and a depth of the concave part is deeper than the predetermined depth.   
     
     
         4 . The method for manufacturing a metal grating structure according to  claim 1 , wherein
 in the insulating layer forming step, an insulating layer is formed on an inner surface of the concave part in the silicon substrate by one of a deposition method, a thermal oxidation method, and an anodic oxidation method.   
     
     
         5 . The method for manufacturing a metal grating structure according to  claim 1 , wherein
 the dry etching method is RIE (reactive ion etching).   
     
     
         6 . The method for manufacturing a metal grating structure according to  claim 1 , wherein
 the dry etching method is a Bosch process.   
     
     
         7 . The method for manufacturing a metal grating structure according to  claim 1 , wherein
 the silicon substrate is an n-type silicon substrate.   
     
     
         8 . The method for manufacturing a metal grating structure according to  claim 1 , wherein
 the method is used for manufacturing a diffraction grating for use in an X-ray Talbot interferometer or an X-ray Talbot-Lau interferometer.   
     
     
         9 . A metal grating structure manufactured by the method for manufacturing a metal grating structure of  claim 1 . 
     
     
         10 . An X-ray imaging device, comprising:
 an X-ray source which outputs an X-ray;   a Talbot interferometer or a Talbot-Lau interferometer on which the X-ray output from the X-ray source is irradiated; and   an X-ray imaging element which captures an image of X-ray by the Talbot interferometer or the Talbot-Lau interferometer, wherein   the Talbot interferometer or the Talbot-Lau interferometer includes the metal grating structure of  claim 9 .   
     
     
         11 . An intermediate product for a metal grating structure provided with a silicon substrate in which a plurality of concave parts are formed according to a predetermined pattern, wherein
 each of the concave parts has an insulating layer formed on an inner surface of the concave part from an opening end of the concave part to a predetermined depth in a depth direction of the concave part, the silicon substrate being exposed from the inner surface in a region from a position corresponding to the predetermined depth to a deepest end of the concave part.