Monoalkyl tin compounds with low polyalkyl contamination, their compositions and methods
A pure composition comprises a monoalkyltin trialkoxide compound represented by the chemical formula RSn(OR′) 3 or a monoalkyl tin triamide compound represented by the chemical formula RSn(NR′ 2 ) 3 and no more than 4 mole % dialkyltin compounds relative to the total tin amount, where R is a hydrocarbyl group with 1-31 carbon atoms, and wherein R′ is a hydrocarbyl group with 1-10 carbon atoms. Methods are described for the formation of the pure compositions. A solid composition comprises a monoalkyl triamido tin compound represented by the chemical formula RSn—(NR′COR″) 3 , where R is a hydrocarbyl group with 1-31 carbon atoms, and where R′ and R″ are independently a hydrocarbyl group with 1-10 carbon atoms. The compositions are suitable for the formation of resist compositions suitable for EUV patterning in which the compositions have a high EUV absorption.
1. A method to form a monoalkyltin triamide compound, the method comprising,
reacting an alkylating agent selected from the group consisting of RMgX, R 2 Zn, RZnNR′ 2 , or a combination thereof, with Sn(NR′ 2 ) 4 in a solution comprising an organic solvent,
wherein R is a hydrocarbyl group with 1-31 carbon atoms,
wherein X is a halogen, and
wherein R′ is a hydrocarbyl group with 1-10 carbon atoms.
2. The method of claim 1 wherein the solution has a concentration between about 0.01 M and about 5 M in tin.
3. The method of claim 1 wherein the organic solvent comprises an alkane, an aromatic hydrocarbon, an ether, or mixtures thereof.
4. The method of claim 1 wherein the solution has a concentration of alkylating agent from about ±25% relative to a stoichiometric reaction of the tin reagent and the alkylating agent.
5. The method of claim 1 wherein the reaction is performed under an inert atmosphere with gradual addition of the alkylating agent with shading from ambient lighting.
6. The method of claim 1 wherein the alkylating agent is added gradually over a time period of 10 minutes to 90 minutes.
7. The method of claim 1 wherein the reaction is performed over a period of 15 minutes to 24 hours at a temperature from −100° C. to 100° C.
8. The method of claim 1 wherein the solution further comprises from 0.25 to 4 mole equivalents of neutral coordinating base relative to tin.
9. A method to selectively form a monoalkyltin trialkoxide compound with low dialkyl tin contamination, the method comprising,
reacting RSn(NR′ 2 ) 3 with an alcohol represented by the formula HOR″ in an organic solvent to form RSn(OR″) 3 , wherein the RSn(NR′ 2 ) 3 reactant has no more than about 4 mole % dialkyl tin contaminants and is the product of the method of claim 1 , wherein R is a hydrocarbyl group with 1-31 carbon atoms, and wherein R′ and R″ are independently a hydrocarbyl group with 1-10 carbon atoms.
10. The method of claim 9 wherein the alcohol is t-amyl alcohol.
11. The method of claim 9 wherein the organic solvent comprises an alkane, an aromatic hydrocarbon, an ether, or mixtures thereof.
12. The method of claim 9 wherein the organic solvent comprises pentane, hexane, toluene, diethyl ether, or mixtures thereof.
13. The method of claim 9 wherein the solution has a concentration of alcohol from about ±5% relative to a stoichiometric reaction of the tin reagent and the alcohol.
14. The method of claim 9 wherein the reaction is performed with a tetradentate chelating agent in an amount from about 0.5 mole % to about 15 mole % relative to the tin molar quantity.
15. The method of claim 14 wherein the chelating agent is tri(2-aminoethyl)amine or triethylenetetraamine.
16. The method of claim 1 wherein the monoalkyltin triamide compound is selectively formed with no more than 1 mole percent polyalkyl tin contamination.
17. The method of claim 1 wherein the dialkyl tin contamination is no more than about 4 mole %.
18. The method of claim 1 wherein R is a methyl group and R′ is a t-butyl group or a cyclohexyl group or a cycloheptyl group.
19. The method of claim 1 wherein the alkylating agent is t-BuMgCl or cyclohexyl zinc bromide or dicycloheptyl zinc.