SUPERCRITICAL CARBON DIOXIDE/CHEMICAL FORMULATION FOR ASHED AND UNASHED ALUMINUM POST-ETCH RESIDUE REMOVAL
(19)AUSTRALIAN PATENT OFFICE (54) TitleSUPERCRITICAL CARBON DIOXIDE/CHEMICAL FORMULATION FOR ASHED AND UNASHEDALUMINUM POST-blCH RESIDUE REMOVAL (51)6 International Patent Classification(s) C09K 013/00 C03C 015/00 C09K 013/08 C09K 013/04 H01L 021/302 C09K 013/06 (21) Application No: 2003284932 (22) Application Date: 2003.10.27 (87) WIPONo: WO04/041965 (30) Priority Data (31) Number (32) Date 10/285,015 2002.10.31 (33) Country US (43) Publication Date : 2004.06.07 (43) Publication Journal Date : 2004.07.01 (71) Applicant(s) ADVANCED TECHNOLOGY MATERIALS , INC. (72) Inventor(s)XU, Chongying; BAUM, Thomas, H.;KORZENSKI, Michael, B.; GHENCIU, Eliodor, G. (H) Application NoAU2003284932 A1(19)AUSTRALIAN PATENT OFFICE (54) TitleSUPERCRITICAL CARBON DIOXIDE/CHEMICAL FORMULATION FOR ASHED AND UNASHEDALUMINUM POST-blCH RESIDUE REMOVAL (51)6 International Patent Classification(s) C09K 013/00 C03C 015/00 C09K 013/08 C09K 013/04 H01L 021/302 C09K 013/06 (21) Application No: 2003284932 (22) Application Date: 2003.10.27 (87) WIPONo: WO04/041965 (30) Priority Data (31) Number (32) Date 10/285,015 2002.10.31 (33) Country US (43) Publication Date : 2004.06.07 (43) Publication Journal Date : 2004.07.01 (71) Applicant(s) ADVANCED TECHNOLOGY MATERIALS , INC. (72) Inventor(s)XU, Chongying; BAUM, Thomas, H.;KORZENSKI, Michael, B.; GHENCIU, Eliodor, G. A post-etch residue cleaning composition for cleaning ashed or unashed aluminum/SiN/Si post-etch residue from small dimensions on semiconductor substrates. The cleaning composition contains supercritical CO<SUB>2 </SUB>(SCCO2), alcohol, fluoride source, an aluminum ion complexing agent and, optionally, corrosion inhibitor. Such cleaning composition overcomes the intrinsic deficiency of SCCO2 as a cleaning reagent, viz., the non-polar character of SCCO2 and its associated inability to solubilize species such as inorganic salts and polar organic compounds that are present in the post-etch residue and that must be removed from the semiconductor substrate for efficient cleaning. The cleaning composition enables damage-free, residue-free cleaning of substrates having ashed or unashed aluminum/SiN/Si post-etch residue thereon. A supercritical carbon dioxide-based cleaning composition, comprising supercritical carbon dioxide (SCCO2), alcohol, a fluorine source, and an aluminum ion complexing agent, wherein said composition is further defined by at least one of the following (I) or (II):
(I) wherein the aluminum ion complexing agent comprises a complexing agent selected from the group consisting of salicylic acid, EDTA, oxalic acid, beta-diketones, gallic acid, nitrilotriacetic acid, 3-hydroxy-2-naphthoic acid, and oxine; or(II) wherein the cleaning composition further comprises a corrosion inhibitor; and
wherein said supercritical carbon dioxide-based cleaning composition is useful for the removal of alurninum/SiNISi post-etch residue from a substrate having same thereon. The composition of claim 1, wherein the alcohol comprises at least one C1-C4 alcohol. The composition of claim 1, wherein the alcohol comprises methanol. The composition of claim 1, wherein the fluorine source comprises a fluorine-containing compound selected from the group consisting of hydrogen fluoride (HF), amine trihydrogen fluoride compounds of the formula NR3(HF)3 wherein each R is independently selected from hydrogen and C1-C8 alkyl, hydrogen fluoride-pyridine (pyr-HF), and ammonium fluorides of the formula R4NF, wherein each R is independently selected from hydrogen and C1-C8 alkyl. The composition of claim 1, wherein the fluorine source comprises triethylamine trihydrogen fluoride. The composition of claim 1, wherein the supercritical carbon dioxide-based cleaning composition comprises supercritical carbon dioxide. The composition of claim 1, wherein the aluminum ion complexing agent comprises a complexing agent selected from the group consisting of salicylic acid, EDTA, gallic acid, nitrilotriacetic acid, 3-hydroxy-2-naphthoic acid, and oxine. The composition of claim 1, wherein the aluminum ion complexing agent comprises salicylic acid. The composition of claim 1, comprising (I), further comprising a corrosion inhibitor. The composition of claims I and 9, wherein said corrosion inhibitor includes boric acid. The composition of claim 1, wherein the alcohol increases the solubility of the composition for inorganic salts and polar organic compounds present in the aluminum/SiN/Si post-etch residue, relative to a corresponding composition lacking such alcohol. The composition of claims 1 and 9, wherein the fluorine source is ammonium fluoride, the aluminum ion complexing agent is salicylic acid and the corrosion inhibitor is boric acid. The composition of claim 1, wherein the aluminum ion complexing agent has a concentration of from about 0.01 to about 2.0 wt.%, based on the total weight of the composition. The composition of claim 12, wherein the molar ratio ammonium fluoride : salicylic acid : boric acid is of about 1.50:1.53:1.0. The composition of claim 12, wherein the molar ratio ammonium fluoride : salicylic acid: boric acid is of about 1.10:1.0:0.73. The composition of claim 12, wherein the alcohol comprises methanol, and wherein ammonium fluoride is present at a concentration of from about 0.01 to about 2.0 wt.%, salicylic acid is present at a concentration of from about 0.01 to about 4.0 wt.%, and boric acid is present at a concentration of from about 0.01 to about 2.0 wt %, based on the total weight of the composition. The composition of claims 1 and 3, wherein the supercritical carbon dioxide-based cleaning composition comprises supercritical carbon dioxide and said SCCO2 and methanol form an SCCO2/methanol solution, and wherein the methanol increases the solubility of the composition for inorganic salts and polar organic compounds upon exposure of the composition to an aluminum/SiN/Si post-etch residue, relative to a corresponding composition lacking methanol therein. The composition of claim 1, wherein the aluminum ion complexing agent has a concentration of from about 0.01 to about 2.0 wt.%, based on the total weight of the composition. The composition of claim 1, comprising (II), wherein the alcohol comprises methanol, the fluorine source comprises ammonium fluoride, the aluminum ion complexing agent comprises salicylic acid, and the corrosion inhibitor comprises boric acid. The composition of claim 1, further comprising aluminum/SiN/Si post-etch residue. A method of removing aluminum/SiN/Si post-etch residue from a substrate having same thereon, said method comprising contacting the post-etch residue with a supercritical carbon dioxide-based cleaning composition comprising alcohol, a fluorine source, and an aluminum ion complexing agent for sufficient time and under sufficient contacting conditions to remove the aluminum/SiN/Si post-etch residue from the substrate, wherein said composition is further defined by at least one of the following (I) or (II):
(I) wherein the aluminum ion complexing agent comprises a complexing agent selected from the group consisting of salicylic acid, EDTA, oxalic acid, beta-diketones, gallic acid, nitrilotriacetic acid, 3-hydroxy-2-naphthoic acid, and oxine; or(II) wherein the cleaning composition further comprises a corrosion inhibitor. The method of claim 21, wherein the supercritical carbon dioxide-bascd cleaning composition comprises supercritical carbon dioxide. The method of claim 21, wherein said contacting conditions comprise elevated pressure. The method of claim 21, wherein said elevated pressure comprises pressure in a range of from about 2000 to about 4000 psi. The method of claim 21, wherein said contacting time is in a range of from about 1 to about 35 minutes. The method of claim 21, wherein the fluorine source comprises a fluorine-containing compound selected from the group consisting of hydrogen fluoride (HF), amine trihydrogen fluoride compounds of the formula NR3(HF)3 wherein each R is independently selected from hydrogen and C1-C8 alkyl, hydrogen fluoride-pyridine (pyr-HF), and ammonium fluorides of the formula R4NF, wherein each R is independently selected from hydrogen and C1-C8 alkyl. The method of claim 21, wherein the fluorine source comprises triethylamine trihydrogen fluoride. The method of claim 21, wherein the alcohol comprises at least one C1-C4 alcohol. The method of claim 21, wherein said aluminumISiN/Si post-etch residue comprises an unashed aluminum/SiN/Si post-etch residue. The method of claim 21, comprising (I), wherein the cleaning composition further comprises a corrosion inhibitor. The method of claim 30, wherein said composition comprises methanol as said alcohol, salicylic acid as said aluminum ion complexing agent, ammonium fluoride as said fluorine source and boric acid as said corrosion inhibitor, wherein ammonium fluoride is present at a concentration of from about 0.01 to about 1.0 wt. %, salicylic acid is present at a concentration of from about 0.01 to about 2.0 wt% and boric acid is present at a concentration of from about 0.01 to about 1.0% wt. % based on the total weight of the composition. The method of claim 31, wherein the supercritical carbon dioxide-based cleaning composition comprises supercritical carbon dioxide and said SCCO2 and methanol form an SCCO2/methanol solution, and wherein the methanol increases the solubility of the composition for inorganic salts and polar organic compounds upon exposure of the composition to the aluminum/SiN/Si post-etch residue, relative to a corresponding composition lacking methanol therein. The method of claim 31, wherein said SCCO2-based composition comprises ammonium fluoride, salicylic acid, and boric acid in a molar ratio of about 1.50:1.53:1.0 (ammonium fluoride:salicylic acid:boric acid). The method of claim 29, wherein said contacting time is in a range of from about 1 to about 15 minutes. The method of claim 21, wherein said aluminum/SiN/Si post-etch residue comprises an ashed aluminum/SiN/Si post-etch residue. The method of claim 31, wherein said composition comprises ammonium fluoride, salicylic acid, and boric acid in a molar ratio of about 1.10:1.0:0.73 (ammonium fluoride:salicylic acid:boric acid). The method of claim 21, wherein the step of contacting the post-etch residue with a composition comprises a cleaning cycle including (i) dynamic flow contacting of the composition with the post-etch residue, and (ii) static soaking contacting of the composition with the post-etch residue. The method of claim 37, wherein said cleaning cycle comprises alternatingly and repetitively carrying out dynamic flow contacting (i) and static soaking contacting (ii) of the post-etch residue. The method of claim 37, wherein said cleaning cycle comprises carrying out (i) dynamic flow contacting and (ii) static soaking contacting in sequence, and repeating said sequence three times. The method of claim 39, wherein each of said (i) dynamic flow contacting and (ii) static soaking contacting is carried out in said cleaning cycle for a contacting period of from about 2.5 to about 5 minutes. The method of claim 35, wherein total contacting time in said cleaning cycle is from about 15 to about 35 minutes. The method of claim 21, further comprising the step of washing the substrate at a region at which the aluminum/SiN/Si post-etch residue has been removed, with a SCCO2/alcohol wash solution in a first washing step, and with SCCO2 in a second washing step, to remove residual precipitated chemical additives in said first washing step, and to remove residual precipitated chemical additives and/or residual alcohol in said second washing step. The method of claim 42, wherein the SCCO2/alcohol wash solution comprises methanol. The method of claim 21, comprising (II), wherein the alcohol comprises methanol, the fluorine source comprises ammonium fluoride, the aluminum ion complexing agent comprises salicylic acid, and the corrosion inhibitor comprises boric acid. The method of claim 21, wherein the composition further comprises aluminum/SiN/Si post-etch residue. The method of claim 21, wherein the aluminum ion complexing agent comprises a complexing agent selected from the group consisting of salicylic acid, EDTA, gallic acid, nitrilotriacetic acid, 3-hydroxy-2-naphthoic acid, and oxine.