Process for producing a multifunctional dielectric layer on a substrate

Abstract

A multifunctional dielectric layer can be formed on a substrate, especially on an exposed metallic strip conductor system on a substrate. An additional metal layer is formed across the surface of the exposed metal strip conductors. The metal layer is then at least partially converted to a nonconducting metal oxide, the dielectric layer.

1 . A process for producing a multifunctional dielectric layer on a substrate, the process comprising: 
 forming a plurality of metal interconnects that are embedded in an insulator and have been provided with a diffusion barrier at the side walls;    applying a further metal layer to uncovered portions of the metal interconnects as a metallic covering, the further metal layer comprising a metal, a metal nitride or a layer sequence of these materials; and    converting the further metal layer into a nonconducting metal oxide thereby forming a dielectric layer.    
   
   
       2 . The process as claimed in  claim 1 , wherein the dielectric layer comprises a barrier layer on at least some interconnects.  
   
   
       3 . The process as claimed in  claim 1 , wherein the dielectric layer comprises a capacitor dielectric for at least one of the interconnects.  
   
   
       4 . The process as claimed in  claim 1 , further comprising covering parts of the further metal layer such that the covered parts form resistors.  
   
   
       5 . The process as claimed in  claim 1 , wherein the metal interconnects comprise a material selected from the group consisting of copper, aluminum, tungsten, and gold.  
   
   
       6 . The process as claimed in  claim 1 , wherein the further metal layer is deposited on the metal interconnects, which have a subtractive architecture, by virtue of a metal layer that has been deposited over the entire surface of an insulator on the substrate having subsequently been patterned.  
   
   
       7 . The process as claimed in  claim 6 , wherein the metal interconnects comprise aluminum, copper, tungsten, silicides, or nitrides.  
   
   
       8 . The process as claimed in  claim 1 , wherein the further metal layer is applied to metal interconnects that have been produced by pattern plating on an insulator on the substrate.  
   
   
       9 . The process as claimed in  claim 1 , wherein converting the further metal layer into a nonconducting metal oxide is carried out by a thermal and/or anodic and/or plasma-chemical oxidation.  
   
   
       10 . The process as claimed in  claim 1 , wherein the oxidation takes place in a temperature range between 20-500° C.  
   
   
       11 . The process as claimed in  claim 1 , wherein the further metal layer is formed by a PVD process.  
   
   
       12 . The process as claimed in  claim 1 , wherein the diffusion barrier is formed by depositing tantalum.  
   
   
       13 . The process as claimed in  claim 1 , wherein the diffusion barrier is formed by depositing Ta(N).  
   
   
       14 . The process as claimed in  claim 1 , wherein the diffusion barrier comprises Ti, Al, Zr, Hf. Nb, Ru, Rh, and/or Ir.  
   
   
       15 . The process as claimed in  claim 1 , wherein regions of the further metal layer are removed during the converting.  
   
   
       16 . The process as claimed in  claim 1 , wherein parts of the further metal layer are covered with an SiO 2  or Si 3 N 4  layer during the converting.  
   
   
       17 . The process as claimed in  claim 1 , wherein a metal thin film resistor and a MIM capacitor are at least partially formed by the steps of forming a further metal layer and converting the further metal layer.  
   
   
       18 . A process for producing a multifunctional dielectric layer on an uncovered metallic interconnect system on a substrate, the interconnect system including metal interconnects that have been embedded in an insulator on a substrate and have been provided with a diffusion barrier at side walls, the method comprising: 
 performing a chemical mechanical polishing process to expose an upper surface of the metal interconnects;    applying a further metal layer, formed from a metal, a metal nitride or a layer sequence of these materials, to the uncovered metal interconnects as a metallic covering layer following the chemical mechanical polishing process; and    converting portions of the further metal layer into a nonconducting metal oxide thereby forming a dielectric layer as a barrier layer on some interconnects and as a capacitor dielectric on other interconnects, wherein portions of the further metal layer, which have been covered, are not converted and form resistors.