Porous inorganic solids for use as low dielectric constant materials
This disclosure relates generally to polymeric networks of fullerene compounds, to methods of preparing precursors for such networks, and to their subsequent use as low dielectric constant materials in microelectronic devices.
1. A method of producing a porous film, comprising:
providing a functionalized fullerene monomer comprising at least one reactive arm;
condensing the functionalized fullerene monomer to form a partially condensed fullerene oligomer;
combining the partially condensed fullerene oligomer with an inorganic oxide precursor to form a composite mixture;
applying the composite mixture to a substrate;
curing the composite mixture; and
removing at least a portion of the partially condensed fullerene oligomer to obtain the porous film.
2. The method of claim 1 , wherein the functionalized fullerene monomer comprises a fullerene and at least one reactive arm, wherein the at least one reactive arm comprises:
a reactive group coupled to the fullerene;
an organic spacer portion; and
a metal or metalloid alkoxide.
3. The method of claim 2 , wherein the functionalized fullerene monomer comprises a C 60 fullerene.
4. The method of claim 2 , wherein the at least one reactive arm comprises:
an amine, an azide, a diene or a carbanion;
an alkyl organic spacer portion; and
a metal or metalloid alkoxide selected from the group consisting of: —Si(OR) 3 , —Ge(OR) 3 , —Ti(OR) 3 , —Zr(OR) 3 , —Sn(OR) 3 , —Al(OR) 2 , and —B(OR) 2 .
5. The method of claim 1 , wherein the at least one reactive arm is selected from the group consisting of: 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminoethyl-3-aminopropyltrimethoxysilane, 2-aminoethyl-3-aminopropyltriethoxysilane, diethylenetriaminopropyltrimethoxysilane, hexane-diaminomethyltriethoxysilane, and 11-aminoundecyltriethoxysilane.
6. The method of claim 1 , wherein the condensing comprises contacting the functionalized fullerene monomer with water.
7. The method of claim 1 , wherein the inorganic oxide precursor is poly(ethoxysilane).
8. The method of claim 1 , wherein the applying comprises spin-coating, dip-coating or spray-coating the composite mixture.
9. The method of claim 1 , wherein the curing comprises heating the composite mixture to between about 80° C. to 200° C. under a moist atmosphere.
10. The method of claim 1 , wherein the removing comprises an oxidation treatment of at least a portion of the fullerene monomer.
11. The method of claim 10 , wherein the removing comprises thermal oxidation, oxonolysis or oxygen plasma treatment of at least a portion of the fullerene oligomer.
12. A method of producing a porous film, comprising:
adding aminohexyltriethoxysilane to a plurality of fullerenes, wherein amino groups of the aminohexyltriethoxysilane react with the fullerenes to generate functionalized fullerenes;
adding water to the functionalized fullerenes, thereby condensing silane groups of the aminohexyltriethoxysilane to generate partially condensed fullerene oligomers;
combining the partially condensed fullerene oligomers with poly(ethoxysilane) to form a composite mixture;
applying the composite mixture to a substrate;
curing the composite mixture; and
removing at least a portion of the partially condensed fullerene oligomers to obtain the porous film.
13. The method of claim 12 , wherein the applying comprises coating the composite mixture on a silicon wafer.
14. The method of claim 12 , wherein the curing comprises heating the composite mixture to greater than about 80° C.
15. The method of claim 12 , wherein the removing comprises heating the composite mixture to greater than about 300° C. in the presence of oxygen.