Use of non-oxidizing strong acids for the removal of ion-implanted resist
A method and composition for removing bulk and/or ion-implanted resist material from microelectronic devices have been developed. The compositions effectively remove the ion-implanted resist material while not damaging the silicon-containing or germanium-containing materials.
1. A composition comprising:
(a) at least one non-oxidizing acid present in an amount greater than 80 wt %, at least one of a fluoride species and/or a bromide compound, and at least one compound that lowers the melting point of the composition, with the proviso that the composition is substantially devoid of oxidizers, and wherein the pH of the composition is less than 2, wherein the at least one fluoride species comprises hydrofluoric acid in an amount of from about 0.01 wt% to about 1 wt % or a species in an amount of from about 0.01 wt % to about 8 wt % selected from the group consisting of hydrofluoric acid, tetrafluoroboric acid, hexafluorotitanic acid, hexafluorosilicic acid, hexafluorozirconic acid, tetrafluoboric acid, tetrabutylammonium trifluoromethanesulfonate, tetraalkylammonium tetrafluoroborates (NR1R2R3R4BF4) tetraalkylammonium hexafluorophosphates (NR1R2R3R4PF6), tetraalkylammonium fluorides (NR1R2R3R4F), ammonium bifluoride, ammonium fluoride, and combinations thereof, where R1, R2, R3, R4 may be the same as or different from one another and is selected from the group consisting of hydrogen, straight-chained or branched C1-C6 alkyl groups, C1-C6 alkoxy groups, and substituted or unsubstituted aryl groups, and combinations thereof;
(b) a sulfur-containing acid present in an amount greater than 90 wt %, HCl , and optionally at least one fluoride and/or at least one bromide compound; or
(c) a sulfur-containing acid present in an amount greater than 90% and an HCl-generating compound,
wherein when in contact with a surface of a microelectronic device, the composition removes ion-implanted resist material from the surface of the microelectronic device while not substantially damaging silicon- containing materials and germanium-containing materials present on the surface of the microelectronic device.
2. The composition of claim 1 , wherein the at least one non-oxidizing acid comprises a species selected from the group consisting of methanesulfonic acid, oxalic acid, citric acid, tartaric acid, picolinic acid, succinic acid, acetic acid, lactic acid, sulfosuccinic acid, benzoic acid, propionic acid, formic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, fumaric acid, malic acid, ascorbic acid, mandelic acid, heptanoic acid, butyric acid, valeric acid, glutaric acid, phthalic acid, hypophosphorous acid, salicylic acid, 5-sulfosalicylic acid, ethanesulfone acid, butanesulfonic acid, p-toluenesulfonic acid, dichloroacetic acid, difluoroacetic acid, monochloroacetic acid, monofluoroacetic acid, hydrochloric acid, trichloroacetic acid, trifluoroacetic acid, hydrobromic acid, sulfuric acid, and combinations thereof.
3. The composition of claim 1 , wherein the HCl -generating compound comprises a species selected from the group consisting of thionyl chloride (SOCl2), phosphoryl trichloride (POCl3), sulfuryl chloride (SO2Cl2), boron trichloride (BCl3), germanium tetrachloride (GeCl4), chlorosulfonic acid, (ClSO3H), and combinations thereof.
4. The composition of claim 1 , comprising at least one bromide species, wherein the atleast one bromide species comprises hydrobromic acid.
5. The composition of claim 1 , wherein the at least one compound that lowers the melting point of the composition comprises at least one dialkyl sulfone, sulfuric acid, or sulfolane.
6. The composition of claim 5 , wherein the at least one dialkyl sulfone comprises a species selected from the group consisting of dimethylsulfone, ethyl methyl sulfone, dipropyl sulfone, ethyl propyl sulfone, diethyl sulfone, dibutyl sulfone, and combinations thereof.
7. The composition of claim 1 , wherein the sulfur-containing acid comprises a species selected from the group consisting of concentrated sulfuric acid, 100% sulfuric acid, “fuming” sulfuric acid (containing excess SO 3 ), chlorosulfonic acid (ClSO 3 H), mixtures of chlorosulfonic acid and sulfuric acid, trifluoromethanesulfonic acid (CF 3 SO 3 H) and fluorosulfonicacid (FSO 3 H).
8. The composition of claim 1 , wherein the composition (b) is substantially devoid of oxidizers.
9. The composition of claim 1 , wherein the composition (a) is substantially devoid of added water.
10. The composition of claim 1 , wherein the composition (b) is substantially devoid of added water.