Composition and process for selectively etching a layer comprising an aluminium compound in the presence of layers of low-k materials, copper and/or cobalt

Abstract

A composition for selectively etching a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt is described, and a corresponding use of said composition. Further is described a process for the manufacture of a semiconductor device, comprising the step of selectively etching at least one layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt by contacting the at least one layer comprising an aluminium compound with the described composition.

1 . A composition comprising:
 (A) at least one solubilizer, selected from the group consisting of   a compound of formula I:   
       
         
           
           
               
               
           
         
         wherein R 1  is at least one selected from the group consisting of hydrogen and —C(O)—R 2  wherein R 2  is selected from the group consisting of hydrogen and alkyl having 1, 2, 3 or 4 carbon atoms; 
         a compound of formula II: 
       
       
         
           
           
               
               
           
         
         wherein R 3  is alkyl having 1, 2, 3 or 4 carbon atoms; 
         trimethylamine-N-oxide, 
         triethylamine-N-oxide, 
         triethanolamine-N-oxide, 
         pyridine-N-oxide, and 
         N-ethylpyrrolidine-N-oxide; 
         (B) an etchant comprising fluoride anions; 
         (C) at least one corrosion inhibitor, selected from the group consisting of 
         benzotriazole which is unsubstituted or substituted once or twice independently by C 1-4 -alkyl, amino-C 1-4 -alkyl, phenyl, thiophenyl, halogen, hydroxy, nitro and/or thiol; 
         ethylene urea, ethylene thiourea, 1,2,4-triazole, 5-aminotetrazole, 5-amino-1,3,4-thiadiazol-2-thiol, 3-amino-1H-1,2,4 triazole, 3,5-diamino-1,2,4-triazole, tolyltriazole, 3-amino-5-mercapto-1,2,4-triazole, 1-amino-1,2,4-triazole, 1-amino-1,2,3-triazole, 1-amino-5-methyl-1,2,3-triazole, 3-mercapto-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, naphthotriazole, 1 H-tetrazole-5-acetic acid, 1-phenyl-2-tetrazoline-5-thione, 4-methyl-2-phenylimidazole, 2-mercaptothiazoline, 2,4-diamino-6-methyl-1,3,5-triazine, thiazole, imidazole, benzimidazole, triazine, methyltetrazole, 1,3-dimethyl-2-imidazolidinone, 1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole, 2H-imidazole-2-thione, 4-methyl-4H-1,2,4-triazole-3-thiol, 5-amino-1,3,4-thiadiazole-2-thiol, benzothiazole, tritolyl phosphate, indazole, adenine, cytosine, guanine, thymine, 2,2′-azanediyldiacetic acid, propanethiol, citric acid, ascorbic acid, thiourea, 1,1,3,3-tetramethylurea, urea, uric acid, glycine, dodecylphosphonic acid, oxalic acid, malonic acid, succinic acid, and nitrilotriacetic acid; 
         (D) at least one chelating agent selected from the group consisting of histidine, 1,2-cyclohexylenedinitrilotetraacetic acid, 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, acetylacetonate, 2,2′-azanediyldiacetic acid, ethylenediaminetetraacetic acid, etidronic acid, methanesulfonic acid, acetylacetone, 1,1,1-trifluoro-2,4-pentanedione, 1,4-benzoquinone, 8-hydroxyquinoline, salicylidene aniline; tetrachloro-1,4-benzoquinone, 2-(2-hydroxyphenyl)-benzoxazol, 2-(2-hydroxyphenyl)-benzothiazole, hydroxyquinoline sulfonic acid, sulfosalicylic acid, salicylic acid, pyridine, 2-ethylpyridine, 2-methoxypyridine, 3-methoxypyridine, 2-picoline, dimethylpyridine, piperidine, piperazine, triethylamine, triethanolamine, ethylamine, methylamine, isobutylamine, tert-butylamine, tributylamine, dipropylamine, dimethylamine, diglycol amine, monoethanolamine, methyldiethanolamine, pyrrole, isoxazole, bipyridine, pyrimidine, pyrazine, pyridazine, quinoline, isoquinoline, indole, 1-methylimidazole, diisopropylamine, diisobutylamine, aniline, pentamethyldiethylenetriamine, acetoacetamide, ammonium carbamate, ammonium pyrrolidinedithiocarbamate, dimethyl malonate, methyl acetoacetate, N-methyl acetoacetamide, tetramethylammonium thiobenzoate, 2,2,6,6-tetramethyl-3,5-heptanedione, tetramethylthiuram disulfide, lactic acid, ammonium lactate, formic acid, propionic acid, and gamma-butyrolactone; and 
         (G) water. 
       
     
     
         2 . The composition according to  claim 1 , wherein
 the at least one solubilizer (A) is selected from the group consisting of   a compound of formula I; and   a compound of formula II;   the etchant (B) is at least one selected from the group consisting of ammonium fluoride, ammonium bifluoride, triethanolammonium fluoride, diglycolammonium fluoride, methyldiethanolammonium fluoride, tetramethylammonium fluoride, triethylamine trihydrofluoride, hydrogen fluoride, fluoroboric acid, tetrafluoroboric acid, ammonium tetrafluoroborate, fluoroacetic acid, ammonium fluoroacetate, trifluoroacetic acid, fluorosilicic acid, ammonium fluorosilicate, and tetrabutylammonium tetrafluoroborate; and/or   the at least one corrosion inhibitor (C) is selected from the group consisting of   benzotriazole which is unsubstituted or substituted once or twice independently by C 1-4 -alkyl, amino-C 1-4 -alkyl, phenyl, thiophenyl, halogen, hydroxy, nitro and/or thiol;   succinic acid.   
     
     
         3 . The composition according to  claim 1 ,
 wherein   the at least one chelating agent (D) is selected from the group consisting of histidine and 1,2-cyclohexylenedinitrilotetraacetic acid, and/or   the composition comprises as further component:   (E) a surfactant.   
     
     
         4 . The composition according to  claim 1 ,
 wherein   a pH of the composition is in the range of from 3.5 to 8, and/or   the composition comprises as further component:   (F) a buffering system which is suitable to buffer a pH of the composition in the range of from 3.5 to 8.   
     
     
         5 . The composition according to  claim 1 , comprising
 (A) at least one solubilizer selected from the group consisting of   a compound of formula I, and   a compound of formula II;   (B) at least one etchant, selected from the group consisting of ammonium fluoride, ammonium bifluoride, triethanolammonium fluoride, diglycolammonium fluoride, methyldiethanolammonium fluoride, tetramethylammonium fluoride, triethylamine trihydrofluoride, hydrogen fluoride, fluoroboric acid, tetrafluoroboric acid, ammonium tetrafluoroborate, fluoroacetic acid, ammonium fluoroacetate, trifluoroacetic acid, fluorosilicic acid, ammonium fluorosilicate, and tetrabutylammonium tetrafluoroborate;   (C) at least one corrosion inhibitor, selected from the group consisting of   benzotriazole which is unsubstituted or substituted once or twice independently by C 1-4 -alkyl, amino-C 1-4 -alkyl, phenyl, thiophenyl, halogen, hydroxy, nitro and/or thiol, and   succinic acid   (D) at least one chelating agent selected from the group consisting of histidine, and 1,2-cyclohexylenedinitrilotetraacetic acid and   (G) water,   wherein a pH of the composition is in the range of from 3.5 to 8.   
     
     
         6 . The composition according to  claim 1 , the composition comprising:
 (A) at least one solubilizer, selected from the group consisting of 4-methylmorpholine-4-oxide, trimethylamine-N-oxide, triethylamine-N-oxide, triethanolamine-N-oxide, pyridine-N-oxide, N-ethylmorpholine-N-oxide, and N-ethylpyrrolidine-N-oxide and mixtures thereof;   (B) an etchant comprising fluoride anions;   (C) at least one corrosion inhibitor, selected from the group consisting of benzotriazole, 6-methyl-benzotriazole, 5-methyl-benzotriazole, ethylene urea, ethylene thiourea, 1,2,4-triazole, 5-aminotetrazole, 1-hydroxybenzotriazole, 5-amino-1,3,4-thiadiazol-2-thiol, 3-amino-1H-1,2,4 triazole, 3,5-diamino-1,2,4-triazole, tolyltriazole, 5-phenyl-benzotriazole, 5-nitro-benzotriazole, 3-amino-5-mercapto-1,2,4-triazole, 1 -amino-1,2,4-triazole, 2-(5-amino-pentyl)-benzotriazole, 1 -amino-1,2,3-triazole, 1 -amino-5-methyl-1,2,3-triazole, 3-mercapto-1,2,4-triazole, 3-isopropyl-1,2,4-triazole, 5-phenylthiol-benzotriazole, halobenzotriazoles, naphthotriazole, 1 H-tetrazole-5-acetic acid, 2-mercaptobenzothiazole, 1-phenyl-2-tetrazoline-5-thione, 2-mercaptobenzimidazole, 4-methyl-2-phenylimidazole, 2-mercaptothiazoline, 2,4-diamino-6-methyl-1,3,5-triazine, thiazole, imidazole, benzimidazole, triazine, methyltetrazole, 1,3-dimethyl-2-imidazolidinone, 1,5-pentamethylenetetrazole, 1-phenyl-5-mercaptotetrazole, 2H-imidazole-2-thione, 4-methyl-4H-1,2,4-triazole-3-thiol, 5-amino-1,3,4-thiadiazole-2-thiol, benzo-thiazole, tritolyl phosphate, indazole, adenine, cytosine, guanine, thymine, 2,2′-azanediyldiacetic acid, propanethiol, citric acid, ascorbic acid, thiourea, 1,1,3,3-tetramethylurea, urea, uric acid, glycine, dodecylphosphonic acid, oxalic acid, malonic acid, succinic acid, and nitrilotriacetic acid;   (D) at least one chelating agent selected from the group consisting of 1,2-cyclohexylenedinitrilotetraacetic acid, 1,1,1,5,5,5-hexafluoro-2,4-pentane-dione, acetylacetonate, 2,2′-azanediyldiacetic acid, ethylenediaminetetraacetic acid, etidronic acid, methanesulfonic acid, acetylacetone, 1,1,1-trifluoro-2,4-pentanedione, 1,4-benzoquinone, 8-hydroxyquinoline, salicylidene aniline; tetrachloro-1,4-benzoquinone, 2-(2-hydroxyphenyl)-benzoxazol, 2-(2-hydroxyphenyl)-benzothiazole, hydroxyquinoline sulfonic acid, sulfosalicylic acid, salicylic acid, pyridine, 2-ethylpyridine, 2-methoxypyridine, 3-methoxypyridine, 2-picoline, dimethylpyridine, piperidine, piperazine, triethylamine, triethanolamine, ethylamine, methylamine, isobutylamine, tert-butylamine, tributylamine, dipropylamine, dimethylamine, diglycol amine, monoethanolamine, methyldiethanolamine, pyrrole, isoxazole, bipyridine, pyrimidine, pyrazine, pyridazine, quinoline, isoquinoline, indole, 1 -methylimidazole, diisopropylamine, diisobutylamine, aniline, pentamethyldiethylenetriamine, acetoacetamide, ammonium carbamate, ammonium pyrrolidinedithiocarbamate, dimethyl malonate, methyl acetoacetate, N-methyl acetoacetamide, tetramethylammonium thiobenzoate, 2,2,6,6-tetramethyl-3,5-heptanedione, tetramethylthiuram disulfide, lactic acid, ammonium lactate, formic acid, propionic acid, and gamma-butyrolactone;   (E) at least one surfactant;   (F) a buffering system which is suitable to buffer a pH of the composition in the range of from 6 to 8, and   (G) water,   wherein the pH of the composition is in the range of from 6 to 8.   
     
     
         7 . The composition according to  claim 3 , wherein the total amount of the at least one solubilizer (A) present is in the range of from 0.01 to 20 wt. % based on the total weight of the composition. 
     
     
         8 . The composition according to  claim 5 , wherein the total amount of the at least one etchant (B) present is in the range of from 0.001 to 1 wt. % based on the total weight of the composition. 
     
     
         9 . The composition according to  claim 1 , wherein the total amount of the at least one corrosion inhibitor (C) present is in the range of from 0.01 to 4 wt.-% based on the total weight of the composition. 
     
     
         10 . A method comprising:
 contacting the composition according to  claim 1  with a substrate,   wherein the method is suitable   for selectively etching a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt;   for selectively removing from a substrate a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt, and/or   for selectively removing from the surface of a semiconductor substrate a layer comprising an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt.   
     
     
         11 . The method according to  claim 10 , wherein the method comprises a two-step-process of removing
 (i) a metal hard mask, and   (ii) an etch-stop layer of an aluminium compound deposited on a layer comprising copper and/or a layer comprising cobalt.   
     
     
         12 . A process for manufacturing a semiconductor device, the process comprising:
 selectively etching at least one layer comprising or consisting of an aluminium compound in the presence of a layer of a low-k material and/or a layer comprising copper and/or cobalt, by contacting the at least one layer of an aluminium compound at least once with the composition according to  claim 1 .   
     
     
         13 . The process according to  claim 12 , wherein the at least one layer comprising or consisting of an aluminium compound is a top layer and the layer comprising copper and/or cobalt is a lower layer covered by the top layer, with or without at least one further layer being present in between the top layer and the lower layer. 
     
     
         14 . The process according to  claim 12 , the process comprising a two-step cleaning process, the process comprising
 removing in a first step a metal hard mask,   before selectively etching in a separate second step the at least one layer comprising or consisting of an aluminium compound.   
     
     
         15 . The process according to  claim 12 , wherein the at least one layer comprising or consisting of an aluminium compound before etching has a maximum thickness of 30 nm or below.