Methods for Forming a Barrier Layer with Periodic Concentrations of Elements and Structures Resulting Therefrom

Abstract

A method is provided which includes dispensing and removing different deposition solutions during an electroless deposition process to form different sub-films of a composite layer. Another method includes forming a film by an electroless deposition process and subsequently annealing the microelectronic topography to induce diffusion of an element within the film. Yet another method includes reiterating different mechanisms of deposition growth, namely interfacial electroless reduction and chemical adsorption, from a single deposition solution to form different sub-films of a composite layer. A microelectronic topography resulting from one or more of the methods includes a film formed in contact with a structure having a bulk concentration of a first element. The film has periodic successions of regions each comprising a region with a concentration of a second element greater than a set amount and a region with a concentration of the second element less than the set amount.

1 . A method for processing a microelectronic topography, comprising:
 positioning the microelectronic topography within an electroless plating chamber;   dispensing a first electroless plating solution upon the microelectronic topography to form a first sub-film within the electroless plating chamber;   removing the first electroless plating solution from the electroless plating chamber subsequent to the formation of the first sub-film; and   dispensing a second electroless plating solution upon the microelectronic topography subsequent to the removal of the first electroless plating solution to form a second sub-film upon and in contact with the first sub-film, wherein the second sub-film comprises multiple elements included within the first sub-film, and wherein a concentration of at least one of the elements within the second sub-film differs from a concentration of the same element within the first sub-film.   
     
     
         2 . The method of  claim 1 , wherein the second sub-film consists essentially of the same elements as included in the first sub-film. 
     
     
         3 . The method of  claim 1 , further comprising establishing chamber process parameters different than those used during the formation of the first sub-film prior to the step of dispensing the second electroless plating solution. 
     
     
         4 . The method of  claim 3 , wherein the first and second electroless plating solutions comprise substantially equal compositions. 
     
     
         5 . The method of  claim 1 , wherein the first and second electroless plating solutions comprise substantially different compositions. 
     
     
         6 . The method of  claim 1 , wherein at least one of the first and second electroless plating solutions comprises maleic acid and a component comprising cobalt. 
     
     
         7 . The method of  claim 1 , wherein at least one of the first and second electroless plating solutions comprises pyrophosphoric acid and a component comprising cobalt. 
     
     
         8 . The method of  claim 1 , wherein at least one of the first and second electroless plating solutions comprise hydroxyethyl ethylenediamine triacetic acid and a component comprising cobalt. 
     
     
         9 . The method of  claim 1 , wherein at least one of the first and second electroless plating solutions comprise ammonium hydroxide and a component comprising ruthenium. 
     
     
         10 . The method of  claim 1 , further comprising terminating and subsequently resuming the step of dispensing the first electroless plating solution during formation of the first sub-film. 
     
     
         11 . The method of  claim 1 , further comprising:
 rotating a substrate holder upon which the microelectronic topography is positioned within the electroless plating chamber; and   terminating and subsequently resuming the step of rotating the substrate holder during formation of the first sub-film.   
     
     
         12 . The method of  claim 1 , further comprising:
 removing the second deposition solution from the electroless plating chamber subsequent to the formation of the second sub-film; and   repeating the steps of dispensing and removing the first deposition solution subsequent to the removal of the second deposition solution to form a third sub-film upon and in contact with the second sub-film.   
     
     
         13 . The method of  claim 12 , further comprising establishing chamber process parameter settings different than those used during the formation of the first sub-film prior to the step of repeating the steps of dispensing and removing the first deposition solution. 
     
     
         14 . The method of  claim 1 , further comprising:
 removing the second electroless plating solution from the electroless plating chamber subsequent to the formation of the second sub-film; and   reiterating the steps of dispensing and removing the first electroless plating solution and the steps of dispensing and removing the second electroless plating solution subsequent to the formation of the second sub-film to form additional sub-films above the second sub-film.   
     
     
         15 . The method of  claim 1 , further comprising:
 removing the second electroless plating solution from the electroless plating chamber subsequent to the formation of the second sub-film; and   consecutively dispensing and removing one or more additional electroless plating solutions different than the first and second electroless plating solutions subsequent to the removal of the second electroless plating solution to form one or more additional sub-films above the second sub-film.   
     
     
         16 . The method of  claim 1 , wherein one of the first and second electroless plating solutions comprises an agent to slow the adsorption of the at least one element during the respective step of forming the first or second sub-film. 
     
     
         17 . A method for processing a microelectronic topography, comprising:
 forming a bulk metallic film upon the microelectronic topography using an electroless plating process, wherein the bulk metallic film comprises a bottom portion, a top portion, and an intermediate portion interposed between the bottom and top portions, wherein one of the top and bottom portions comprises a higher concentration of a first element than the intermediate portion and the other of the top and bottom portions; and   annealing the microelectronic topography to induce diffusion of the first element within the bulk metallic film such that the intermediate portion comprises a higher concentration of the first element than the bottom and top portions.   
     
     
         18 . The method of  claim 17 , wherein the step of forming the bulk metallic film comprises forming the bulk metallic film upon and in contact with a metallic structure having a bulk elemental concentration different than the film, and wherein the bottom portion of the bulk metallic film comprises a higher concentration of the first element than the intermediate portion and the top portion prior to the step of annealing the microelectronic topography. 
     
     
         19 . The method of  claim 17 , wherein the step of forming the bulk metallic film comprises forming the bulk metallic film upon and in contact with a dielectric structure, and wherein the top portion of the bulk metallic film comprises a higher concentration of the first element than the intermediate portion and the bottom portion prior to the step of annealing the microelectronic topography. 
     
     
         20 . The method of  claim 17 , wherein the first element comprises phosphorus. 
     
     
         21 . The method of  claim 17 , wherein the step of annealing the microelectronic topography further comprises diffusing one or more other elements through the bulk metallic film such that the intermediate portion comprises a higher concentration of the one or more elements than the bottom and top portions. 
     
     
         22 . The method of  claim 17 , wherein the step of annealing the microelectronic topography comprises exposing the microelectronic topography to a heated environment comprising a second element different from the first element. 
     
     
         23 . A method for depositing a film upon a microelectronic topography, comprising:
 exposing the microelectronic topography to a electroless plating solution;   forming a first sub-film portion by interfacial electroless reduction of a first element within the electroless plating solution until a second different element reaches a certain concentration within the electroless plating solution, wherein the first sub-film comprises a higher concentration of the first element than the second element;   forming a second sub-film portion upon and in contact with the first sub-film portion by chemical adsorption until the first element increases to a particular concentration within the electroless plating solution, wherein the second sub-film comprises a higher concentration of the second element than the first element; and   reiterating the steps of forming the first and second sub-film portions to form a composite film comprising concentration variations of the first and second elements.   
     
     
         24 . The method of  claim 23 , wherein the first element is cobalt and the second element is molybdenum. 
     
     
         25 . The method of  claim 23 , wherein the first element is oxygen and the second element is molybdenum. 
     
     
         26 . The method of  claim 23 , wherein the electroless plating solution comprises an agent to slow the adsorption of the second element during the step of forming the second sub-film portion.