Reactivity enhancement in ion beam etcher

Abstract

A method of fabricating a slanted surface-relief structure in a material layer using a chemically assisted reactive ion beam etching (CARIBE) system includes generating, by a reactive ion source generator of the CARIBE system using a first reactive gas, a plasma including reactive ions of the first reactive gas that are configured to react with the material layer to generate volatile materials; extracting and accelerating, by one or more grids of the CARIBE system, at least some of the reactive ions in the plasma to form a reactive ion beam towards the material layer; and injecting, by a gas ring of the CARIBE system, a second reactive gas onto the material layer, the second reactive gas configured to react with the material layer. The reactive ion beam and the second reactive gas etch the material layer both physically and chemically to form the slanted surface-relief structure in the material layer.

What is claimed is: 
     
         1 . A method of fabricating a slanted surface-relief structure in a material layer using a chemically assisted reactive ion beam etching (CARIBE) system, the method comprising:
 generating, by a reactive ion source generator of the CARIBE system, a plasma using a first reactive gas, the plasma including reactive ions of the first reactive gas that are configured to react with the material layer to generate volatile materials;   extracting and accelerating, by one or more grids of the CARIBE system, at least some of the reactive ions in the plasma to form a reactive ion beam towards the material layer; and   injecting, by a gas ring of the CARIBE system, a second reactive gas onto the material layer, the second reactive gas configured to react with the material layer,   wherein the reactive ion beam and the second reactive gas etch the material layer both physically and chemically to form the slanted surface-relief structure in the material layer.   
     
     
         2 . The method of  claim 1 , further comprising injecting, by a neutralizer of the CARIBE system, an electron beam into the reactive ion beam to neutralize the reactive ion beam. 
     
     
         3 . The method of  claim 1 , further comprising rotating, by a rotation stage of the CARIBE system, a substrate that include the material layer based on a desired slant angle of the slanted surface-relief structure. 
     
     
         4 . The method of  claim 3 , wherein rotating the substrate comprises rotating the substrate at a rotation angle greater than 30° such that a slant angle of the slanted surface-relief structure is greater than 30° with respect to a surface normal of the material layer. 
     
     
         5 . The method of  claim 1 , further comprising controlling, using a shutter or a blade of the CARIBE system, etch time, etch regions, or both of etching the material layer both physically and chemically. 
     
     
         6 . The method of  claim 1 , wherein the reactive ion source generator comprises an inductively coupled plasma generator. 
     
     
         7 . The method of  claim 1 , further comprising injecting, through a gas inlet of the CARIBE system, the first reactive gas into the reactive ion source generator of the CARIBE system. 
     
     
         8 . The method of  claim 1 , wherein extracting and accelerating, by the one or more grids of the CARIBE system, at least some of the reactive ions in the plasma to form the reactive ion beam towards the material layer comprises:
 applying an extraction voltage on an extraction grid adjacent to the reactive ion source generator; and   applying an acceleration voltage on an acceleration grid aligned with the extraction grid to extract and accelerate at least some of the reactive ions,   wherein the acceleration voltage is lower than the extraction voltage; and   wherein the reactive ion beam is a collimated reactive ion beam.   
     
     
         9 . The method of  claim 1 , wherein the first reactive gas comprises at least one of CF 4 , CHF 3 , N 2 , O 2 , SF 6 , H 2 , Cl 2 , BCl 3 , HBr, Ar, He, or Ne. 
     
     
         10 . The method of  claim 1 , wherein the second reactive gas comprises at least one of CF 4 , CHF 3 , N 2 , O 2 , SF 6 , Cl 2 , BCl 3 , or HBr. 
     
     
         11 . The method of  claim 1 , wherein the material layer includes a semiconductor substrate, a SiO 2  layer, a Si 3 N 4  material layer, a titanium oxide layer, an alumina layer, a SiC layer, a SiO x N y  layer, an amorphous silicon layer, a spin on carbon (SOC) layer, an amorphous carbon layer (ACL), a diamond like carbon (DLC) layer, a TiO x  layer, an AlO x  layer, a TaO x  layer, or a HFO x  layer. 
     
     
         12 . The method of  claim 1 , wherein the slanted surface-relief structure comprises a slanted surface-relief optical grating. 
     
     
         13 . The method of  claim 12 , wherein the slanted surface-relief optical grating comprises a plurality of ridges, a leading edge of each ridge being parallel to a trailing edge of the ridge. 
     
     
         14 . The method of  claim 12 , wherein a depth of the slanted surface-relief optical grating is greater than 100 nm. 
     
     
         15 . The method of  claim 12 , wherein a duty cycle of the slanted surface-relief optical grating is greater than 60%.