Method for forming fine pitch structures

Abstract

A mold having an open interior volume is used to define patterns. The mold has a ceiling, floor and sidewalls that define the interior volume and inhibit deposition. One end of the mold is open and an opposite end has a sidewall that acts as a seed sidewall. A first material is deposited on the seed sidewall. A second material is deposited on the deposited first material. The deposition of the first and second materials is alternated, thereby forming alternating rows of the first and second materials in the interior volume. The mold and seed layer are subsequently selectively removed. In addition, one of the first or second materials is selectively removed, thereby forming a pattern including free-standing rows of the remaining material. The free-standing rows can be utilized as structures in a final product, e.g., an integrated circuit, or can be used as hard mask structures to pattern an underlying substrate. The mold and rows of material can be formed on multiple levels. The rows on different levels can crisscross one another. Selectively removing material from some of the rows can from openings to form, e.g., contact vias.

We claim: 
     
         1 . A method for semiconductor processing, comprising:
 sequentially laterally growing a first plurality of alternating rows formed of first and the second materials on a first level over a substrate, wherein the rows alternate as seen in a top-down view;   selectively removing the rows formed of the first material relative to the rows formed of the second material; and   transferring a pattern formed by the rows of the second material to the substrate.   
     
     
         2 . The method of  claim 1 , wherein sequentially laterally growing comprises depositing an initial row formed of the first material before depositing an initial row formed of the second material. 
     
     
         3 . The method of  claim 2 , further comprising forming a wall on the substrate before sequentially laterally growing, wherein sequentially laterally growing comprises depositing the initial row formed of the first material directly on the wall. 
     
     
         4 . The method of  claim 1 , wherein transferring the pattern to the substrate comprises defining trenches in the substrate. 
     
     
         5 . The method of  claim 4 , wherein the trenches are disposed parallel to one another. 
     
     
         6 . The method of  claim 4 , wherein the substrate comprises an insulator and wherein the trenches are formed in the insulator, further comprising:
 filling the trenches with a metal.   
     
     
         7 . The method of  claim 6 , wherein filling the trenches forms electrical interconnects. 
     
     
         8 . The method of  claim 1 , further comprising sequentially laterally growing a second plurality of alternating rows of different materials on a second level over the first level, wherein the rows alternate as seen in a top-down view. 
     
     
         9 . The method of  claim 8 , wherein sequentially laterally growing the second plurality of alternating rows is performed before selectively removing the rows formed of the first material. 
     
     
         10 . The method of  claim 9 , further comprising depositing a deposition inhibiting layer over the first plurality of alternating rows before sequentially laterally growing the second plurality of alternating rows. 
     
     
         11 . The method of  claim 10 , further comprising:
 selectively removing one of the materials forming the second plurality of alternating rows, thereby forming a set of rows separated by openings, wherein the openings expose portions of the deposition inhibiting layer;   selectively removing the exposed portions of the deposition inhibiting layer, thereby exposing portions of the first plurality of alternating rows; and   selectively removing the exposed portions of the first plurality of alternating rows, thereby forming a plurality of vertically-elongated holes.   
     
     
         12 . A method for semiconductor processing, comprising:
 alternatingly depositing rows of a first material and rows of a second material on a level over a substrate; and   selectively removing the rows of the first material relative to the rows of the second material.   
     
     
         13 . The method of  claim 12 , wherein alternatingly depositing comprises depositing an initial row of the first material before depositing an initial row of the second material. 
     
     
         14 . The method of  claim 12 , wherein alternatingly depositing comprises depositing rows of one or more additional materials in a sequence with depositing rows of the first and second materials. 
     
     
         15 . The method of  claim 12 , wherein alternatingly depositing comprises forming the rows of the first material by a vapor deposition process. 
     
     
         16 . The method of  claim 15 , wherein alternatingly depositing comprises forming the rows of the first material by atomic layer deposition. 
     
     
         17 . The method of  claim 15 , wherein alternatingly depositing comprises forming the rows of the second material by a vapor deposition process 
     
     
         18 . The method of  claim 17 , wherein alternatingly depositing comprises forming the rows of the second material by atomic layer deposition. 
     
     
         19 . A method for semiconductor processing, comprising:
 performing a plurality of cycles of row formation on a level over a substrate, each cycle comprising:
 depositing a row of a first material; and 
 depositing a row of a second material; 
   forming a etch mask by removing rows of the first material relative to rows of the second material, the rows of the first material forming the etch mask; and   etching underlying material through the etch mask to define a pattern in the underlying material.   
     
     
         20 . The method of  claim 19 , wherein depositing the row of the first material is performed before depositing the row of the second material.