Methods and system for generating a three-dimensional holographic mask

Abstract

A system for surface patterning using a three dimensional holographic mask includes a light source configured to emit a light beam toward the holographic mask. The holographic mask can be formed as a topographical pattern on a transparent mask substrate. A semiconductor substrate can be positioned on an opposite site of the holographic mask as the light source and can be spaced apart from the holographic mask. The system can also include a base for supporting the semiconductor substrate.

What is claimed is: 
     
         1 . An iterative pixelated perturbation method of generating a three dimensional holographic mask based on a predetermined three dimensional pattern, comprising:
 providing a starting pattern for the holographic mask;   computing images at multiple planes parallel to the holographic mask using a processor;   computing an image metric representing a combination of diffraction efficiency of the holographic mask and fidelity of a resulting image compared with the predetermined pattern for the images at the multiple planes using the processor;   perturbing an optic height of a first pixel in the starting pattern to create an intermediate pattern;   computing the resulting intermediate images and computing an intermediate metric for the intermediate pattern; and   determining whether the intermediate metric for the intermediate pattern is an improvement over the metric for the starting pattern.   
     
     
         2 . The method of  claim 1 , wherein the image metric includes at least one of diffraction efficiency, image fidelity, exposure latitude, line-edge roughness, manufacturability, normalized inverse image slope, robustness, and throughput. 
     
     
         3 . The method of  claim 2 , wherein the image metric includes diffraction efficiency and image fidelity. 
     
     
         4 . The method of  claim 1 , wherein perturbing the optic height of the first pixel comprises at least one of increasing or decreasing the optic height by a predetermined height unit. 
     
     
         5 . The method of  claim 4 , the method further comprising:
 perturbing the optic height of the first pixel in an opposite increasing or decreasing optic height direction when the metric for the intermediate pattern is not an improvement over the metric for the starting pattern to create a second intermediate pattern;   computing the images and computing the metric for the second intermediate pattern; and   determining whether the metric for the second intermediate pattern is an improvement over the metric for the starting pattern.   
     
     
         6 . The method of  claim 5 , further comprising discarding perturbation of the optic height of the first pixel when the metric for the second intermediate pattern is not an improvement over the metric for the starting pattern, and performing the steps of perturbing, computing, and determining for a second pixel. 
     
     
         7 . The method of  claim 1 , further comprising performing the steps of perturbing, computing, and determining for a second pixel when the metric for the intermediate pattern is an improvement over the metric for the starting pattern. 
     
     
         8 . The method of  claim 1 , wherein computing images at multiple planes parallel to the holographic mask comprises computing images corresponding to image slices from the predetermined three dimensional pattern. 
     
     
         9 . The method of  claim 6 , wherein the images are two dimensional or three dimensional images. 
     
     
         10 . The method of  claim 1 , further comprising fabricating the holographic mask as a topographical pattern on a transparent substrate. 
     
     
         11 . A system for surface patterning using a three dimensional holographic mask, comprising:
 a light source configured to emit a light beam toward the holographic mask;   the holographic mask formed as a topographical pattern on a transparent mask substrate;   a semiconductor substrate on an opposite site of the holographic mask as the light source, the semiconductor substrate being spaced apart from the holographic mask; and   a base for supporting the semiconductor substrate.   
     
     
         12 . The system of  claim 11 , further comprising a beam expander positioned between the light source and the holographic mask, the beam expander being configured to expand the light beam. 
     
     
         13 . The system of  claim 11 , wherein the base comprises a mobile base configured to move the semiconductor substrate in an x, y, or z dimension. 
     
     
         14 . The system of  claim 11 , wherein the semiconductor substrate is a non-planar surface. 
     
     
         15 . The system of  claim 11 , wherein the holographic mask enables patterning of the semiconductor substrate in both step-wise patterns and angled patterns. 
     
     
         16 . A method of patterning a resist using a three dimensional holographic mask, comprising:
 positioning the holographic mask between a light source and a semiconductor substrate, and spaced apart from the semiconductor substrate, the holographic mask being formed as a topographical pattern on a transparent mask substrate; and   illuminating the holographic mask with the light source to project a predetermined pattern in three spatial dimensions onto the semiconductor substrate.   
     
     
         17 . The method of  claim 16 , further comprising:
 rotationally moving the semiconductor substrate in one of x, y, or z dimensions; and   illuminating the holographic mask with the light source to project the predetermined pattern in three spatial dimensions onto a second portion of the semiconductor substrate.   
     
     
         18 . The method of  claim 16 , wherein illuminating the holographic mask to project the predetermined pattern onto the semiconductor substrate comprises illuminating the holographic mask to project the predetermined pattern onto a first portion of the semiconductor substrate, the method further comprising:
 linearly moving the semiconductor substrate in one of x, y, or z dimensions; and   illuminating the holographic mask with the light source to project the predetermined pattern in three spatial dimensions onto a second portion of the semiconductor substrate.   
     
     
         19 . The method of  claim 18 , wherein the second portion of the semiconductor substrate is at a different elevation than the first portion of the semiconductor substrate. 
     
     
         20 . The method of  claim 16 , wherein the semiconductor substrate comprises a resist layer thereon, the method further comprising:
 exposing the resist layer to create a resist layer pattern;   etching the predetermined pattern into the semiconductor substrate using the resist layer pattern to create a three dimensional topography in the semiconductor substrate.