Compositions of low-k dielectric sols containing nonmetallic catalysts

Abstract

A sol composition for producing a porous low-k dielectric material is provided. The composition can include at least one silicate ester, a polar solvent, water, an acid catalyst for silicate ester hydrolysis, an amphiphilic block copolymer surfactant, and a nonmetallic catalyst that reduces dielectric constant in the produced material. The composition can further include a metallic ion at a lower parts-per-million concentration than the nonmetallic catalyst, and/or the composition can further include a cosolvent. A method of preparing a thin film on a substrate using the sol composition is also provided.

What is claimed is: 
     
         1 . A sol composition for producing a porous low-k dielectric material, comprising:
 at least one silicate ester,   a polar solvent,   water,   an acid catalyst for silicate ester hydrolysis,   an amphiphilic block copolymer surfactant, and   a nonmetallic catalyst that reduces dielectric constant in the produced material   
     
     
         2 . The composition of  claim 1 , further comprising a metallic ion at a lower parts-per-million concentration than the nonmetallic catalyst. 
     
     
         3 . The composition of  claim 1 , further comprising a cosolvent. 
     
     
         4 . The composition of  claim 1 , wherein the nonmetallic catalyst comprises constituent atoms selected from the group consisting of B, C, N, O, H, Si, P, and a combination thereof. 
     
     
         5 . The composition of  claim 4 , wherein the nonmetallic catalyst comprises: a quaternary ammonium ion in combination with an anionic group; or a tertiary amine oxide. 
     
     
         6 . The composition of  claim 5 , wherein the quaternary ammonium ion in combination with an anionic group is glycine, betaine, arginine, cyameline, 1,3-dimethylimidazolium 2-carboxylate, or nicotinic acid, and the tertiary amine oxide is trimethylamine N-oxide (TMANO), pyridine N-oxide, 4-aminopyridine N-oxide, quinoline N-oxide, or DABCO-DNODP. 
     
     
         7 . The composition of  claim 4 , wherein the nonmetallic catalyst comprises: a neutral molecule comprising a pronounced dipole; or a neutral molecule comprising a nitrogen bonded to an electron withdrawing atom or group. 
     
     
         8 . The composition of  claim 7 , wherein the neutral molecule comprising a pronounced dipole is 4-nitroaniline, 4-aminobenzonitrile, 4-pyridinecarbonitrile, or Michler's ketone, and the neutral molecule comprising a nitrogen bonded to an electron withdrawing atom or group is NH 2 CN (cyanamide), a salt of the N(CN) 2 -(dicyanamide) anion, ammonium dinitramide (ADN), or chloramine-T. 
     
     
         9 . The composition of  claim 1 , wherein the nonmetallic catalyst comprises a cation. 
     
     
         10 . The composition of  claim 9 , wherein the cation is a stabilized carbocation. 
     
     
         11 . The composition of  claim 10 , wherein the stabilized carbocation is crystal violet or malachite green. 
     
     
         12 . The composition of  claim 1 , wherein the nonmetallic catalyst comprises a zwitterion. 
     
     
         13 . The composition of  claim 12 , wherein the zwitterion is 1,3 dimethyimidazolium-2-carboxylate, glycine betaine, cyameline, arginine, or Reichardt's dye. 
     
     
         14 . The composition of  claim 1 , wherein the nonmetallic catalyst is stable to at least 130° C. 
     
     
         15 . The composition of  claim 1 , wherein the nonmetallic catalyst is at a concentration of between 1 ppm-20,000 ppm, or between 10 ppm-2,000 ppm. 
     
     
         16 . The composition of  claim 1 , wherein the nonmetallic catalyst is stable in water and/or an alcohol at a temperature of >80° C. 
     
     
         17 . The composition of  claim 1 , wherein the nonmetallic catalyst is stable in the presence of an organic silicate in solution. 
     
     
         18 . The composition of  claim 1 , wherein the at least one silicate ester is tetraethyl orthosilicate, the polar solvent is a C 1-4  alcohol, and the amphiphilic block copolymer surfactant is a poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) polymer. 
     
     
         19 . The composition of  claim 1 , wherein the at least one silicate ester is:
 bis(triethoxysilyl)ethane; 1,1,2-tris(triethoxysilyl) ethane; tris(triethoxysilyl)methane; TEOS; MTES; MBTE; or phenyltriethoxysilane (PTES); or a combination thereof.   
     
     
         20 . A method of preparing a thin film on a substrate, comprising
 treating a substrate by depositing the sol composition of  claim 1  onto the substrate;   baking and annealing the treated substrate to form a film.