Stable solutions of monoalkyl tin alkoxides and their hydrolysis and condensation products
Precursor solutions for radiation patternable coatings are formed with an organic solvent and monoalkyl tin trialkoxides in which the water content of the solvent is adjusted to be within 10 percent of a selected value. Generally, the water content of the solvent is adjusted through water addition, although water removal can also be used. In some embodiments, the adjusted water content of the solvent can be from about 250 ppm by weight to about 10,000 ppm by weight. With the appropriate selection of ligands, the adjusted precursor solutions can be stable for at least about 42 days, and in some cases at least 8 months.
1. A plurality of coated substrates each comprising a substrate and a dry coating comprising an organometallic patterning composition having an average thickness from about 6 nanometers (nm) to about 50 nm, wherein the plurality of coated substrates has an average three sigma variation in dry coating thickness of no more than about 1.2 nm with a one centimeter edge exclusion.
2. The plurality of coated substrates of claim 1 wherein the substrate is a wafer comprising silicon.
3. The plurality of coated substrates of claim 1 wherein the dry coating comprises tin.
4. The plurality of coated substrates of claim 3 wherein the dry coating comprises tin oxo hydroxo composition with tin carbon bonds.
5. The plurality of coated substrates of claim 1 wherein the average thickness is from 3 nm to about 25 nm and the average three sigma variation in dry coating thickness is not more than about 1.1 nm.
6. The plurality of coated substrates of claim 1 wherein the coating is formed using spin coating of a solution and drying.
7. The plurality of coated substrates of claim 6 wherein the solution comprises a mixture of alcohol with a selected water content and a first monoalkyl tin trialkoxide (RSn(OR′) 3 ), wherein the solution has a tin concentration from about 0.004 M to about 1.0 M and wherein the selected water content is at least about 250 pm by weight and wherein the solution is stable for at least 42 days.
8. The plurality of coated substrates of claim 7 wherein R and R′ are independently hydrocarbyl groups having from 1 - 31 carbon atoms with one or more carbon atoms optionally substituted with one of more heteroatom functional groups containing O, N, Si, Ge, Sn, Te, halogen atoms, or a combination thereof.
9. The plurality of coated substrates of claim 7 wherein R comprises a hydrocarbyl group substituted with a cyano group, a thio group, a silyl group, an ether group, a keto group, an ester group, a phenyl group, a halogenated group, or a combination thereof.
10. The plurality of coated substrates of claim 7 wherein R comprises a branched alkyl, a cyclo-alkyl, or an alkynyl and R′ comprises methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl, or t-amyl.
11. The plurality of coated substrates of claim 7 wherein the solution is stable for at least 6 months.
12. A method for patterning a radiation sensitive coating, the method comprising:
forming a coating on a substrate surface with an organotin precursor solution wherein the organotin precursor solution has a uniform composition resulting from adjusting the water content of the solvent used to form the organotin precursor solution within about ±15% of a selected water content, wherein the selected water content is from about 250 ppm by weight to about 10,000 ppm by weight, and wherein the organotin precursor solution comprises a mixture of alcohol with the selected water content and a first monoalkyl tin trialkoxide (RSn(OR′) 3 ), wherein R and R′ are independently hydrocarbyl groups having from 1-31carbon atoms with one or more carbon atoms optionally substituted with one of more heteroatom functional groups, wherein the organotin precursor solution has a tin concentration from about 0.004M to about 1.0M;
drying the coating; and
irradiating the dried coating to form a latent image.
13. The method of claim 12 wherein irradiation is performed with EUV radiation.
14. The method of claim 12 wherein forming a coating comprises spin coating.
15. The method of claim 14 wherein the spin coating is performed at 1000 rpm to 7500 rpm after an initial low speed spin.
16. The method of claim 14 wherein a backside rinse and bead edge rinse are performed after completing the spin coating.
17. The method of claim 12 wherein R comprises t-butyl and/or R′ comprises (Ot-amyl) 3 .
18. The method of claim 12 wherein the precursor solution further comprises as an ingredient a second monoalkyl tin trialkoxide distinct from the first monoalkyl tin trialkoxide.