Cobalt capping surface preparation in microelectronics manufacture

Abstract

Cleaning compositions and methods in connection with cobalt-based capping of interconnects in integrated circuit semiconductor devices.

1 . A method of cleaning an interconnect feature comprising metallization and a dielectric surface of a semiconductor integrated circuit device prior to electroless deposition of a cobalt-based capping layer, the method comprising:
 exposing the semiconductor integrated circuit device to a cleaning composition prior to the electroless deposition of the cobalt-capping layer, wherein the cleaning composition comprises a reducing agent, a proton source, and a surfactant, wherein the composition has a pH less than about 6.0.   
   
   
       2 . The method of  claim 1  wherein the reducing agent is selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid. 
   
   
       3 . The method of  claim 1  wherein the reducing agent has a concentration between about 0.5 and about 10 g/L and is selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid. 
   
   
       4 . The method of  claim 1  wherein the proton source is selected from the group consisting of polyphosphoric acid, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid. 
   
   
       5 . The method of  claim 1  wherein the proton source is present in a concentration between about 0.5 and about 50 g/L and is selected from the group consisting of polyphosphoric acid, polyphosphate salt, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid. 
   
   
       6 . The method of  claim 1  wherein the surfactant is selected from the group consisting of naphthalene sulfonic acid, naphthalene phosphate, sodium ethylhexyl sulfate, diphenyl oxide disulfonic acid, triethanolamine salt of lauryl sulfate, ammonium laureth sulfate, alkylbenzene sulfonate, dodecylbenzene sulfonic acid, alkyldiphenyloxide disulfonate salt, and soluble, low molecular weight polypropylene glycol. 
   
   
       7 . The method of  claim 1  wherein the reducing agent is selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid; and the proton source is selected from the group consisting of polyphosphoric acid, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid. 
   
   
       8 . A method of cleaning an interconnect feature comprising metallization and a dielectric surface of a semiconductor integrated circuit device prior to electroless deposition of a cobalt-based capping layer, the method comprising:
 exposing the semiconductor integrated circuit device to a cleaning composition prior to the electroless deposition of the cobalt-capping layer, wherein the cleaning composition comprises:   a reducing agent in a concentration between about 0.5 and about 10 g/L and selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid; and   a proton source is present in a concentration between about 0.5 and about 50 g/L and selected from the group consisting of polyphosphoric acid, polyphosphate salt, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid; and   a surfactant;   wherein the composition has a pH less than about 6.0.   
   
   
       9 . A method of cleaning an electrolessly deposited cobalt alloy or nickel alloy capping layer on an interconnect feature comprising metallization of a semiconductor integrated circuit device, the method comprising:
 exposing the semiconductor integrated circuit device to a cleaning composition a reducing agent; a proton source; a surfactant; and a particle suspension agent.   
   
   
       10 . The method of  claim 9  wherein the reducing agent is selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid. 
   
   
       11 . The method of  claim 9  wherein the reducing agent has a concentration between about 0.5 and about 10 g/L and is selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid. 
   
   
       12 . The method of  claim 9  wherein the proton source is selected from the group consisting of polyphosphoric acid, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid. 
   
   
       13 . The method of  claim 9  wherein the proton source is present in a concentration between about 0.5 and about 50 g/L and is selected from the group consisting of polyphosphoric acid, polyphosphate salt, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid. 
   
   
       14 . The method of  claim 9  wherein the surfactant is selected from the group consisting of naphthalene sulfonic acid, naphthalene phosphate, sodium ethylhexyl sulfate, diphenyl oxide disulfonic acid, triethanolamine salt of lauryl sulfate, ammonium laureth sulfate, alkylbenzene sulfonate, dodecylbenzene sulfonic acid, alkyldiphenyloxide disulfonate salt, and soluble, low molecular weight polypropylene glycol. 
   
   
       15 . The method of  claim 9  wherein the reducing agent is selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid; and the proton source is selected from the group consisting of polyphosphoric acid, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid. 
   
   
       17 . The method of  claim 9  wherein the reducing agent has a concentration between about 0.5 and about 10 g/L and is selected from the group consisting of hypophosphorous acid, glyoxylic acid, formic acid, a salt of hypophosphorous acid, a salt of glyoxylic acid, and a salt of formic acid; and wherein the proton source is present in a concentration between about 0.5 and about 50 g/L and is selected from the group consisting of polyphosphoric acid, polyphosphate salt, solutions of sulfur dioxide (sulfurous acid), sulfuric acid, phosphoric acid, methanesulfonic acid, ethanesulfonic acid, methanedisulfonic acid, acetic acid, carbonic acid, and oxalic acid. 
   
   
       18 . The method of  claim 9  wherein the particle suspension agent is present in a concentration of between about 0.1 and about 5 g/L and is selected from the group consisting of sulfonated polymers, sulfonated compounds, and quaternary amines. 
   
   
       19 . The method of  claim 9  wherein the particle suspension agent is selected from the group consisting of sodium polyvinylsulfonate, poly-4-styrenesulfonic acid, poly(2-acrylamido-2-methyl-1-propanesulfonic acid), and poly(acrylamide-co-diallyl-dimethylammonium chloride).