Method of metallization with a nickel or cobalt alloy for the manufacture of semiconductor devices

Abstract

A method of metallizing a dielectric substrate with a nickel-boron alloy or cobalt-boron alloy to deposit a thin layer of the alloy that exhibits good conductivity. The process includes an activation step that includes two stages of activation with a noble metal such as palladium. Thereafter, the dielectric substrate is metallized with a nickel-boron or cobalt-boron alloy by electroless deposition.

1 . A process for metallizing a mineral oxide substrate with a nickel-boron or cobalt-boron alloy, said metallization process comprising:
 a) activating one or more surfaces of the mineral oxide substrate with a noble metal, wherein the activation step comprises:
 i. a first activation stage comprising the step of activating the surface of the mineral oxide substrate by contacting the surface of the mineral oxide substrate with a first activation solution, the first activation solution comprising a solvent, a noble metal complex with a complexing agent, and an organo-silane bi-functional binder, and thereafter 
 ii. a second activation stage comprising the step of activating the surface of the mineral oxide substrate by contacting the surface of the mineral oxide substrate with a second activation solution, the second activation solution comprising an aqueous solution of acidic pH comprising noble metal ions; and 
   b) contacting the one or more surfaces of the mineral oxide substrate, in the absence of electrical polarization, with an electroless aqueous solution comprising one or more of nickel ions and cobalt ions and a reducing agent comprising boron, to form a nickel-boron or cobalt-boron alloy layer on the surface of the mineral oxide substrate.   
     
     
         2 . The process according to  claim 1 , wherein the noble metal of the first activation stage is selected from the group consisting of ruthenium, rhodium, osmium, iridium, palladium, platinum, gold, silver and combinations of the foregoing, wherein the noble metal is complexed with a complexing agent to form the noble metal complex. 
     
     
         3 . The process according to  claim 1 , wherein the complexing agent comprises ethylenediamine. 
     
     
         4 . The process according to  claim 2 , wherein the noble metal comprises palladium and the palladium is complexed with a suitable complexing agent to form a palladium complex. 
     
     
         5 . The process according to  claim 1 , wherein the concentration of the noble metal complex in the first activation solution is in the range of about 10 −6  M to about 10 −2  M. 
     
     
         6 . The process according to  claim 1 , wherein the organo-silane bi-functional binder in the first activation solution comprises two or three amine functions. 
     
     
         7 . The process according to  claim 6 , wherein the organo-silane bi-functional binder in the first activation solution comprises 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane. 
     
     
         8 . The process according to  claim 1 , wherein the concentration of the organo-silane bi-functional binder in the first activation solution is between 10 −5  M and 10 −1  M. 
     
     
         9 . The process according to  claim 1 , wherein the first activation stage is carried out at a temperature ranging from 50° C. to 80° C. 
     
     
         10 . The process according to  claim 1 , wherein the first activation stage is carried out for a period ranging from 30 seconds to 30 minutes. 
     
     
         11 . The process according to  claim 1 , wherein the noble metal ions of the second activation solution are selected from the group consisting of ruthenium ions, rhodium ions, osmium ions, iridium ions, palladium ions, platinum ions, gold ions, silver ions, and combinations of the foregoing. 
     
     
         12 . The process according to  claim 11 , wherein the noble metals ions comprise palladium ions. 
     
     
         13 . The process according to  claim 1 , wherein the second activation solution is obtained by dissolving in water at least one compound selected from the group consisting of tetrachloropalladic acid, palladium (II) trifluoroacetate, palladium pivalate (II), palladium (II) trimethylacetate, and palladium acetate (II). 
     
     
         14 . The process according to  claim 1 , wherein the noble metal used in the first activation solution is the same as the noble metal used in the second activation solution. 
     
     
         15 . The process according to  claim 1 , wherein the second activation stage is carried out at a temperature ranging from 15° C. to 40° C. for a period of between 5 seconds and 60 seconds. 
     
     
         16 . The process according to  claim 1 , characterized in that the mineral oxide substrate is selected from the group consisting of HfO 2 , SiO 2 , and Al 2 O 3 . 
     
     
         17 . The process according to  claim 1 , further comprising a step of rapid thermal annealing of the nickel-boron or cobalt-boron alloy layer formed on the surface of the mineral oxide substrate. 
     
     
         18 . A three-dimensional semiconductor device obtainable by implementing the method according to  claim 1 . 
     
     
         19 . The process according to  claim 1 , wherein the nickel-boron or cobalt-boron alloy layer has a resistivity of less than 300 μohm·cm when the thickness of the nickel-boron or cobalt-boron alloy layer is less than or equal to 20 nm.