Siloxane-based polymer and method for forming dielectric film using the polymer
A siloxane-based polymer having superior mechanical properties and low dielectric properties and a method for forming a dielectric film using the polymer. The siloxane-based polymer not only has superior mechanical properties, but also exhibits low hygroscopicity and good compatibility with pore-forming materials, which leads to a low dielectric constant. In addition, since the siloxane-based polymer is highly compatible with pore-forming materials and has improved applicability to semiconductor processes, it may be advantageously used as a material for dielectric films of semiconductor devices.
1 . A siloxane-based polymer prepared by the hydrolysis and polycondensation of a monomer represented by Formula 1 below:
wherein R 1 and R 2 are each independently a hydrogen atom, hydroxy, alkoxy, acetoxy, alkyl, aryl, or O—Si(OR) 3 (in which R is a C 1 -C 3 alkyl group); and n is an integer of 2 to 100 (with the proviso that at least one of R 1 and R 2 is a reactive functional group selected from a hydrogen atom, hydroxy, alkoxy, acetoxy, or O—Si(OR) 3 ),
with at least one monomer selected from compounds represented by Formulae 2 to 5 below:
(R 1 ) n Si(OR 2 ) 4-n (2)
wherein R 1 is a hydrogen atom, a C 1 -C 3 alkyl group, a halogen atom, or a C 6 -C 15 aryl group; R 2 is a hydrogen atom, a C 1 -C 3 alkyl group or a C 6 -C 15 aryl group, with the proviso that at least one of R 1 and OR 2 is a hydrolysable functional group; and n is an integer of 0 to 3,
wherein R 1 is a hydrogen atom, a C 1 -C 3 alkyl group or a C 6 -C 15 aryl group; R 2 is a hydrogen atom, a C 1 -C 10 alkyl group or SiX 1 X 2 X 3 (in which X 1 , X 2 and X 3 are each independently a hydrogen atom, a C 1 -C 3 alkyl group, a C 1 -C 10 alkoxy group, or a halogen atom, with the proviso that at least one of X 1 , X 2 and X 3 is a hydrolysable functional group); and p is an integer of 3 to 8,
wherein R 1 is a hydrogen atom, a C 1 -C 3 alkyl group or a C 6 -C 15 aryl group; X 1 , X 2 and X 3 are each independently a hydrogen atom, a C 1 -C 3 alkyl group, a C 1 -C 10 alkoxy group or a halogen atom, with the proviso that at least one of X 1 , X 2 and X 3 is a hydrolysable functional group; m is an integer of 0 to 10; and p is an integer of 3 to 8,
X 3 X 2 X 1 Si—M—SiX 1 X 2 X 3 (5)
wherein X 1 , X 2 and X 3 are each independently a hydrogen atom, a C 1 -C 3 alkyl group, a C 1 -C 10 alkoxy group or a halogen atom, with the proviso that at least one of X 1 , X 2 and X 3 is a hydrolysable functional group; M is a C 1 -C 10 alkylene group or a C 6 -C 15 arylene group, hydrolysates thereof, and condensates thereof,
in an organic solvent in the presence of water and an acid or base catalyst.
2 . The siloxane-based polymer according to claim 1 , wherein the acid catalyst is hydrochloric acid, nitric acid, benzene sulfonic acid, oxalic acid, formic acid, or a mixture thereof; and the base catalyst is potassium hydroxide, sodium hydroxide, triethylamine, sodium bicarbonate, pyridine, or a mixture thereof.
3 . The siloxane-based polymer according to claim 1 , wherein a molar ratio of the total monomers to the acid or base catalyst is in the range of 1:1×10 −5 to 1:10.
4 . The siloxane-based polymer according to claim 1 , wherein a molar ratio of the total monomers to water is in the range of 1:1 to 1:100.
5 . The siloxane-based polymer according to claim 1 , wherein the hydrolysis and the polycondensation are carried out at 0-200° C. for 0.1-100 hours.
6 . The siloxane-based polymer according to claim 1 , wherein the organic solvent is an aliphatic hydrocarbon solvent selected from hexane and heptane; an aromatic hydrocarbon solvent selected from anisole, mesitylene and xylene; a ketone-based solvent selected from methyl isobutyl ketone, 1-methyl-2-pyrrolidinone, cyclohexanone and acetone; an ether-based solvent selected from tetrahydrofuran, isopropyl ether and propylene glycol propyl ether; an acetate-based solvent selected from ethyl acetate, butyl acetate and propylene glycol methyl ether acetate; an alcohol-based solvent selected from isopropyl alcohol and butyl alcohol; an amide-based solvent selected from dimethylacetamide and dimethylformamide; a silicon-based solvent; or a mixture thereof.
7 . The siloxane-based polymer according to claim 1 , wherein the siloxane-based polymer has a weight average molecular weight of 3,000 to 300,000.
8 . A method for forming a dielectric film comprising the steps of
i) dissolving the siloxane-based polymer according to claim 1 and, optionally, a pore-forming material in an organic solvent to prepare a coating solution, and
ii) applying the coating solution to a substrate, followed by heat-curing.
9 . The method according to claim 8 , wherein the pore-forming material is selected from cyclodextrins, polycaprolactones, Brij surfactants, polyethylene glycol-polypropylene glycol-polyethylene glycol triblock copolymer surfactants, and derivatives thereof.
10 . The method according to claim 8 , wherein the pore-forming material is used in an amount of 1% to 70% by weight, based on the total weight of the solid matters of the coating solution.
11 . The method according to claim 8 , wherein the organic solvent is an aliphatic hydrocarbon solvent selected from hexane and heptane; an aromatic hydrocarbon solvent selected from anisole, mesitylene and xylene; a ketone-based solvent selected from methyl isobutyl ketone, 1 -methyl-2-pyrrolidinone, cyclohexanone and acetone; an ether-based solvent selected from tetrahydrofuran, isopropyl ether and propylene glycol propyl ether; an acetate-based solvent selected from ethyl acetate, butyl acetate and propylene glycol methyl ether acetate; an alcohol-based solvent selected from isopropyl alcohol and butyl alcohol; an amide-based solvent selected from dimethylacetamide and dimethylformamide; a silicon-based solvent; or a mixture thereof.
12 . The method according to claim 8 , wherein the coating solution has a solid content of 5-70% by weight, based on the total weight of the coating solution.
13 . The method according to claim 8 , wherein, in step ii), the heat curing is performed at 150-600° C. for 1-180 minutes.
14 . A dielectric film formed by the method according to claim 8 .
15 . A semiconductor device comprising a dielectric film formed by the method according to claim 8.