Method and composition for removing sodium-containing material from microcircuit substrates
View Patent ↗A method and composition for removing sodium-containing materials such as photoresist from microcircuit substrate material utilizes 1,2-Diaminocyclohexanetetracarboxylic Acid in an organic solvent.
1. A method of inhibiting adsorption of sodium-to integrated circuit surfaces during photoresist removal or post-metal etch cleanup with an organic solvent-containing composition, comprising contacting the surface with an organic solvent-containing composition comprising:
a) 1,2-diaminocyclohexanetetracarboxylic acid (CYDTA),
b) a nucleophilic amine present in an amount of from about 1 to less than about 50% by weight of the composition,
c) a non-nitrogen containing weak acid in an amount sufficient to partially neutralize the nucleophilic amine such that the composition has an aqueous pH, when diluted with about 10 parts of water, of about 9.6 to about 10.9, said weak acid having a pKa value in aqueous solution of 2.0 or greater and an equivalent weight of less than 140, and
the solvent is a stripping solvent system having a solubility parameter of from about 8 to about 15 and is present in an amount of from about 50% to about 85% by weight of the composition.
2. The method of claim 1 comprising, on a weight basis, from about 50% to about 85% of N-methyl-2-pyrrolidinone as solvent, from about 1 to about 20% of tetrahydrothiophene-1,1-dioxide as solvent, from about 1 to about 20% of water, from about 1 to about 50% of 2-aminoethanol as the nucleophilic amine, from about 0.05% to about 25% of 1,2-dihydroxybenzene as the non-nitrogen containing weak acid and about 0.01% to 5% of 1,2-diaminocyclohexanetetracarboxylic acid.
3. The method of claim 1 , wherein the non-nitrogen containing weak acid is present in the composition in an amount of from about 0.05% to about 25% by weight of said stripping composition.
4. The method of claim 3 , wherein the non-nitrogen containing weak acid has a pKa of 2.5 or higher.
5. The method of claim 4 wherein the non-nitrogen containing weak acid is 1,2-dihydroxybenzene.
6. The method of claim 5 wherein the nucleophilic amine is 2-aminoethanol.
7. The method of claim 6 wherein the solvent system comprises N-methyl-2-pyrrolidinone and tetrahydrothiophene-1,1-dioxide and optionally up to about 10% water.
8. A composition for inhibiting adsorption of sodium-to integrated circuit surfaces during photoresist removal or post-metal etch cleanup with an organic solvent-containing composition, said organic solvent-containing composition comprising:
a) 1,2-diaminocyclohexanetetracarboxylic acid (CyDTA),
b) a nucleophilic amine present in an amount of from about 1 to less than about 50% by weight of the composition,
c) a non-nitrogen containing weak acid in an amount sufficient to partially neutralize the nucleophilic amine such that the composition has an aqueous pH, when diluted with a bout 10 p arts of water, of a bout 9.6 to about 10.9, said weak acid having a pKa value in aqueous solution of 2.0 or greater and an equivalent weight of less than 140, and
the solvent is a stripping solvent system having a solubility parameter of from about 8 to about 15 and is present in an amount of from about 50% to about 85% by weight of the composition.
9. The composition of claim 8 comprising, on a weight basis, from about 50% to about 85% of N-methyl-2-pyrrolidinone as solvent, from about 1 to about 20% of tetrahydrothiophene-1,1-dioxide as solvent, from about 1 to about 20% of water, from about 1 to about 50% of 2-aminoethanol as the nucleophilic amine, from about 0.05% to about 25% of 1,2-dihydroxybenzene as the non-nitrogen containing weak acid and about 0.01% to 5% of 1,2-diaminocyclohexanetetracarboxylic acid.
10. The composition of claim 8 , wherein the non-nitrogen containing weak acid is present in the composition in an amount of from about 0.05% to about 25% by weight of said stripping composition.
11. The composition of claim 10 , wherein the non-nitrogen containing weak acid has a pKa of 2.5 or higher.
12. The composition of claim 11 wherein the non-nitrogen containing weak acid is 1,2-dihydroxybenzene.
13. The composition of claim 12 wherein the nucleophilic amine is 2-aminoethanol.
14. The composition of claim 13 wherein the solvent system comprises N-methyl-2-pyrrolidinone and tetrahydrothiophene-1,1-dioxide and optionally up to about 10% water.