Organometallic compounds and purification of such organometallic compounds

Abstract

Disclosed herein are methods of purifying compounds useful for the deposition of high purity tin oxide and high purity compounds purified by those methods. Such compounds are those of the Formula as follows R.sub.x—Sn-A.sub.4-x, wherein: A is selected from the group consisting of (Y.sub.aR′.sub.z) and a 3- to 7-membered N-containing heterocyclic group; each R group is independently selected from the group consisting of an alkyl or aryl group having from 1 to 10 carbon atoms; each R′ group is independently selected from the group consisting of an alkyl, acyl or aryl group having from 1 to 10 carbon atoms; x is an integer from 0 to 4; a is an integer from 0 to 1; Y is selected from the group consisting of N, O, S, and P; and z is 1 when Y is O, S or when Y is absent and z is 2 when Y is N or P.

Claims

1. A method purifying an organometallic compound comprising: A) distilling in a first stage an organometallic compound of Formula 1:
R.sub.x—Sn-A.sub.4-x  Formula I wherein: each R group is independently selected from the group consisting of an alkyl group having from 1 to 10 carbon atoms; each R′ group is independently selected from the group consisting of an alkyl group having from 1 to 10 carbon atoms; x is an integer from 0 to 3; wherein distilling in the first stage includes: i) feeding feed material containing the first organometallic compound to a first distillation space at a reduced first pressure, ii) heating the first distillation space to a first temperature to evaporate a portion of the feed material, and iii) removing the evaporated portion of the feed material from the first distillation space such that a distillate is formed; B) distilling, in at least one subsequent stage, the distillate from a previous stage, wherein distilling the distillate from a previous stage includes: i) feeding distillate from a previous stage to a subsequent distillation space at a reduced subsequent pressure, ii) heating the subsequent distillation space to a subsequent temperature to evaporate a portion of the distillate from a previous stage, iii) removing the evaporated portion of the distillate from a previous stage from the subsequent distillation space such that a subsequent distillate is formed; and C) removing a final distillate from last of the subsequent stages, wherein step B is repeated a number of times at a reduced subsequent pressure sufficient to obtain the final distillate of the organometallic compound having purity as measured by nuclear magnetic resonance (NMR) spectroscopy of greater than 98%.

2. The method of claim 1, wherein step B is repeated 1 to 19 times.

3. The method of claim 1, wherein, in each subsequent stage, the distillation space has a subsequent pressure that is lower than a subsequent pressure in a previous stage.

4. The method of claim 3, wherein, in each subsequent stage, a subsequent temperature is lower than a subsequent temperature in a previous stage.

5. The method of claim 1, wherein, in each stage, the heating step is by steam in tubes and, in each subsequent stage, steam in the tubes is the evaporated portion of the feed material or distillate from a previous stage.

6. The method of claim 1, wherein each R group is an independently selected alkyl group having from 1 to 4 carbon atoms.

7. The method of claim 1, wherein each R′ group represents different alkyl groups.

8. The method of claim 1, wherein the organometallic compound of Formula I is selected from the group consisting of Me.sub.2Sn(NMe.sub.2).sub.2, Me.sub.2Sn(NEtMe).sub.2, t-BuSn(NEtMe).sub.3, t-BuSn(NMe.sub.2).sub.3, t-BuSn(NEt.sub.2).sub.3, i-PrSn(NEtMe).sub.3, i-PrSn(NEtMe.sub.2).sub.3, n-PrSn(NEtMe).sub.3, n-PrSn(NEtMe.sub.2).sub.3, EtSn(NEtMe).sub.3, i-BuSn(NEtMe).sub.3, i-BuSn(NEtMe.sub.2).sub.3, n-BusSn(NMe.sub.2).sub.3, sec-BuSn(NMe.sub.2).sub.3, Et.sub.2Sn(NEtMe).sub.2, Me.sub.2Sn(NEtMe).sub.2, Sn(NMe.sub.2).sub.4, Sn(NEt.sub.2).sub.4, Sn(NEtMe).sub.4, Bu.sub.2Sn(NEtMe).sub.2, and Me.sub.2Sn(NEt.sub.2).sub.2.

9. The method of claim 8, wherein the organometallic compound of Formula I is Sn(NMe.sub.2).sub.4.

10. The method of claim 1, wherein at least one of the reduced first pressure and the reduced subsequent pressure are less than 10.sup.−1 torr.

11. A method purifying an organometallic compound comprising: A) distilling in a first stage an organometallic compound of Formula 1:
R.sub.x-Sn-(NR′.sub.2).sub.4−x  Formula I wherein: each R group is independently selected from the group consisting of an alkyl group having from 1 to 10 carbon atoms; each R′ group is independently selected from the group consisting of an alkyl group having from 1 to 10 carbon atoms; x is an integer from 0 to 3; wherein distilling in the first stage includes: i) feeding feed material containing the first organometallic compound to a first distillation space at a reduced first pressure, ii) heating the first distillation space to a first temperature to evaporate a portion of the feed material, and iii) removing the evaporated portion of the feed material from the first distillation space such that a distillate is formed; B) distilling, in at least one subsequent stage, the distillate from a previous stage, wherein distilling the distillate from a previous stage includes: i) feeding distillate from a previous stage to a subsequent distillation space at a reduced subsequent pressure, ii) heating the subsequent distillation space to a subsequent temperature to evaporate a portion of the distillate from a previous stage, iii) removing the evaporated portion of the distillate from a previous stage from the subsequent distillation space such that a subsequent distillate is formed; and C) removing a final distillate from last of the subsequent stages, wherein step B is repeated a number of times at a reduced subsequent pressure sufficient to obtain the final distillate of the organometallic compound having a metal contamination of less than 1 ppm.

12. The method of claim 11, wherein step B is repeated a number of times sufficient to reduce metal contamination to less than 100ppb.

13. The method of claim 12, wherein step B is repeated a number of times sufficient to reduce metal contamination to 1ppb or less.

14. The method of claim 11, wherein step B is repeated 1 to 19 times.

15. The method of claim 11, wherein, in each subsequent stage, the distillation space has a subsequent pressure that is lower than a subsequent pressure in a previous stage.

16. The method of claim 15, wherein, in each subsequent stage, a subsequent temperature is lower than a subsequent temperature in a previous stage.

17. The method of claim 11, wherein, in each stage, the heating step is by steam in tubes and, in each subsequent stage, steam in the tubes is the evaporated portion of the feed material or distillate from a previous stage.

18. The method of claim 11, wherein each R′ group represents different alkyl groups.

19. The method of claim 11, wherein the organometallic compound of Formula I is selected from the group consisting of Me.sub.2Sn(NMe.sub.2).sub.2, Me.sub.2Sn(NEtMe).sub.2, t-BuSn(NEtMe).sub.3, t-BuSn(NMe.sub.2).sub.3, t-BuSn(NEt.sub.2).sub.3, i-PrSn(NEtMe).sub.3, i-PrSn(NEtMe.sub.2).sub.3, n-PrSn(NEtMe).sub.3, n-PrSn(NEtMe.sub.2).sub.3, EtSn(NEtMe).sub.3, i-BuSn(NEtMe).sub.3, i-BuSn(NEtMe.sub.2).sub.3, n-BusSn(NMe.sub.2).sub.3, sec-BuSn(NMe.sub.2).sub.3, Et.sub.2Sn(NEtMe).sub.2, Me.sub.2Sn(NEtMe).sub.2, Sn(NMe.sub.2).sub.4, Sn(NEt.sub.2).sub.4, Sn(NEtMe).sub.4, Bu.sub.2Sn(NEtMe).sub.2, and Me.sub.2Sn(NEt.sub.2).sub.2.

20. The method of claim 19, wherein the organometallic compound of Formula I is Sn(NMe.sub.2).sub.4.

21. The method of claim 11, wherein at least one of the reduced first pressure and the reduced subsequent pressure are less than 10.sup.−1 torr.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows the NMR spectrum of Me.sub.3SnNMe.sub.2.

(2) FIG. 2 shows the NMR spectrum of Sn(NMe.sub.2).sub.4.

(3) FIG. 3 shows the NMR spectrum of Me.sub.2Sn(NEtMe).sub.2.

(4) FIG. 4 shows the NMR spectrum of Bu.sub.2Sn(NMe.sub.2).sub.2.

(5) FIG. 5 shows the NMR spectrum of Me.sub.2SnEt.sub.2.

(6) FIG. 6 shows the NMR spectrum of Me.sub.4Sn.

(7) FIG. 7 shows the NMR spectrum of Bu.sub.2Sn(OMe).sub.2.

(8) FIG. 8 shows the NMR spectrum of Bu.sub.2Sn(OAc).sub.2.

(9) FIG. 9 shows the NMR spectrum of Et.sub.2Sn(NMe.sub.2).sub.2.

(10) FIG. 10 shows the NMR spectrum of Me.sub.2Sn(NEt.sub.2).sub.2.

(11) FIG. 11 shows the NMR spectrum of Sn(Pyrrolodinyl).sub.4.

(12) FIG. 12 shows the NMR spectrum of Bu.sub.2Sn(Pyrrolodinyl).sub.2.

(13) FIG. 13 shows the NMR spectrum of Et.sub.2Sn(Pyrrolodinyl).sub.2.

(14) FIG. 14 shows the NMR spectrum of Me.sub.2Sn(NMe.sub.2).sub.2.

(15) FIG. 15 shows the NMR spectrum of tBuSn(NMe.sub.2).sub.3.

(16) FIG. 16 shows the NMR of the reaction of (NMe.sub.2).sub.4Sn with ethanol.

(17) FIG. 17 shows the NMR of the reaction of Me.sub.3SnNMe.sub.2 with water.

(18) FIG. 18 shows the NMR of the reaction of Bu.sub.2Sn(OAc).sub.2 with methanol.

(19) FIG. 19 shows the NMR of the reaction of Bu.sub.2Sn(OMe).sub.2 with acetic acid.

(20) FIG. 20 shows the NMR of the reaction of Bu.sub.2Sn(NMe.sub.2).sub.2 with methanol.

(21) FIG. 21 shows the NMR of Me.sub.4Sn before and after heating at 200° C.

(22) FIG. 22 shows the NMR of Et.sub.2Sn(NMe.sub.2).sub.2 before and after heating at 200° C.

(23) FIG. 23 shows the NMR of Me.sub.2Sn(NMe.sub.2).sub.2 before and after heating at 150° C.

(24) FIG. 24 shows the decomposition temperatures of illustrative compounds of Formula I.

(25) FIG. 25 shows a schematic of a multistage distillation apparatus.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

(26) Disclosed are organometallic compounds of Formula I, below:
R.sub.x—Sn-A.sub.4-x  Formula I
wherein: A is selected from the group consisting of (Y.sub.aR′.sub.z) and a 3- to 7-membered N-containing heterocyclic group; each R group is independently selected from the group consisting of an alkyl or aryl group having from 1 to 10 carbon atoms; each R′ group is independently selected from the group consisting of an alkyl, acyl or aryl group having from 1 to 10 carbon atoms; x is an integer from 0 to 4; a is an integer from 0 to 1; Y is selected from the group consisting of N, O, S, and P; and z is 1 when Y is O, S or when Y is absent and z is 2 when Y is N or P

(27) Compounds of Formula I include those in which R is selected from the group consisting of alkyl and aryl groups having from 1 to 10 carbon atoms. Particular compounds are those in which R is selected from the group consisting of alkyl and aryl groups having from 1 to 6 carbon atoms. More particular are those in which R is selected from the group consisting of alkyl and aryl groups having from 1 to 4 carbon atoms. Examples of such compounds include those in which R is a methyl, ethyl or a butyl group.

(28) Compounds of Formula I include those in which R′ is selected from the group consisting of alkyl, acyl and aryl groups having from 1 to 10 carbon atoms. Particular compounds are those in which R′ is selected from the group consisting of alkyl, acyl and aryl groups having from 1 to 6 carbon atoms. More particular are those in which R′ is selected from the group consisting of alkyl, acyl and aryl groups having from 1 to 4 carbon atoms. Examples of such compounds include those in which R′ is a methyl group, an ethyl group or an acetyl group.

(29) Compounds of Formula I include those in which Y is selected from the group consisting of N, O, S, and P. Particular compounds are those in which Y is selected from the group consisting of N and O.

(30) Compounds of Formula I include those in which x is an integer from 0 to 4. In particular embodiments, x is an integer from 1 to 3. More preferably, x is 2.

(31) Compounds of Formula I include those in which A is a 3- to 7-membered N-containing heterocyclic group such as aziridinyl, pyrrolidinyl, and piperidinyl. Particular compounds are those in which A is a pyrrolidinyl or piperidinyl group.

(32) Compounds of Formula I include those in which R is an alkyl group and A is an NR′.sub.2 group, and wherein R′ is an alkyl group. Particular compounds are those in which R and R′ represent different alkyl groups.

(33) Compounds of Formula I are thermally stable whilst exhibiting good reactivity. Thus, delivery of the compound to the deposition chamber will take place without decomposition occurring. (decomposition results in a deposited film which will not be uniform). A good stability and reactivity profile, as demonstrated by the compounds of the invention, also means that less material is required to be delivered to the growth chamber (less material is more economic), and cycling will be faster (as there will be less material left in the chamber at the end of the process to be pumped oft), meaning that thicker films can be deposited in shorter times, so increasing throughput. Further, ALD can be carried out at much lower temperatures (or using a wider temperature window) using compounds of Formula I than processes of the art. Thermal stability also means that material can be purified much more easily after synthesis, and handling becomes easier.

(34) Such compounds are useful for encapsulating and protecting the resist layers used in liquid immersion lithography (i.e. acting as a “mask”). Thus, the compounds disclosed herein may be used for the manufacture of a transparent tin oxide film having properties suitable for deposition over photoresists, or other organic masking layers, to allow for protection of the underlying layer during liquid immersion lithography, and which permits the manufacture of devices having improved semiconductor device performance such as low defect density, improved device reliability, high device density, high yield, good signal integrity and suitable power delivery, as required by the industry.

(35) Further, the use of a compound of Formula I in the methods disclosed herein allows for chemical vapour deposition (CVD) and atomic layer deposition (ALD) of tin oxide at a low temperature, and produces films consisting of high purity tin oxide having low metallic impurities, and >99% step coverage (i.e. high comformality) over device features and topography.

(36) Compounds of Formula I may be prepared by processes known in the art. The examples below are illustrative of such processes, but are not intended to be limiting.

Example 1: Synthesis of Me.SUB.3.Sn(NMe.SUB.2.)

(37) In a 250 mL flask was charged 20 mL of 2.5M Butyllithium solution in hexane and 50 mL of anhydrous hexane. To the solution, Me.sub.2NH gas was passed till fully reacted and the reaction mixture was stirred for 2 hrs. The solution of 10 g of Me.sub.3SnCl in 100 mL of anhydrous hexane was then added and the mixture was stirred for 12 hrs. Filtration was carried out to remove solid. The solvent was removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. NMR confirmed the product to be Me.sub.3SnNMe.sub.2, as shown in FIG. 1.

Example 2: Synthesis of Sn(NMe.SUB.2.).SUB.4

(38) In a 250 mL flask was charged 80 mL of 2.5M Butyllithium solution in hexane and 50 mL of anhydrous hexane. To the solution, Me.sub.2NH gas was passed till fully reacted and the reaction mixture was stirred for 2 hrs. The solution of 13 g of SnCl.sub.4 in 100 mL of anhydrous benzene was then added and the mixture was refluxed for 4 hrs. Once cooled, filtration was carried out to remove solid. The solvent was removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. NMR confirmed the product to be Sn(NMe.sub.2).sub.4, as shown in FIG. 2.

Example 3: Synthesis of Me.SUB.2.Sn(NEtMe).SUB.2

(39) Under inert atmosphere, a 1 L round bottom flask was charged with 25.00 mL of 2.5M Butyllithium solution in hexane and 200 mL of anhydrous hexane, followed by a slow addition of 5.40 mL of HNEtMe in 100 mL of anhydrous hexane. The reaction mixture was then stirred at room temperature for 1 h. The solution of 6.70 g of Me.sub.2SnCl.sub.2 in 200 mL of anhydrous benzene was then added to the flask (while cooled in the ice bath), and the reaction mixture was left stirring at room temperature overnight. The solvent was removed under reduced pressure from the filtrate. The liquid product was isolated by distillation under reduced pressure (80° C. at 9.8×10.sup.−2 Torr). As shown in FIG. 3, the product was confirmed to be Me.sub.2Sn(NEtMe).sub.2 by NMR spectroscopy.
1) nBuLi+HNEtMe.fwdarw.LiNEtMe+butane  Formula II
2) Me.sub.2SnCl.sub.2+2LiNEtMe.fwdarw.Me.sub.2Sn(NEtMe).sub.2+2LiCl  Formula III

Example 4: Synthesis of Bu.SUB.2.Sn(NMe.SUB.2.).SUB.2

(40) In a 250 mL flask was charged 24 mL of 2.5M Butyllithium solution in hexane and 100 mL of anhydrous hexane. To the solution, Me.sub.2NH gas was passed till fully reacted and the reaction mixture was stirred for 2 hrs. The solution of 9.11 g of Bu.sub.2SnCl.sub.2 in 100 mL of anhydrous benzene was then added and the mixture was stirred for 4 hrs. Filtration was carried out to remove solid. The solvent was removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. NMR confirmed the product to be Bu.sub.2Sn(NMe.sub.2).sub.2, as shown in FIG. 4.

Example 5: Synthesis of Me.SUB.2.SnEt.SUB.2

(41) 6.59 g of Me.sub.2SnCl.sub.2 was dissolved in 100 mL of anhydrous ether, followed by the addition of 30 mL of 3M EtMgBr under N.sub.2. After stirring for 4 hrs, mixture was treated with 0.1M HCl solution and organic layer was collected. The collected organic layer was then treated with saturated NaHCO.sub.3 solution and organic layer is collected. Distillation under N.sub.2 was carried out to remove ether. Purification was carried out by distillation under reduced pressure. As shown in FIG. 5, NMR confirmed the product to be Me.sub.2SnEt.sub.2.

Example 6: Synthesis of Me.SUB.4.Sn

(42) To the solution of 23.5 g of SnCl.sub.4 in ether was added 150 mL of 3M MeMgI under N.sub.2. After stirring for 4 hrs, mixture was treated with 0.1 M HCl solution and organic layer was collected. The collected organic layer was then treated with saturated NaHCO.sub.3 solution and organic layer is collected. Fractional distillation was carried out to remove ether. Purification was carried out by distillation under reduced pressure. As shown in FIG. 6, NMR confirmed the product to be Me.sub.4Sn.

Example 7: Synthesis of Bu.SUB.2.Sn(OMe).SUB.2

(43) To a 250 mL flask was charged 20 g of Bu.sub.2SnCl.sub.2 and 20 mL of anhydrous methanol, followed by the addition of 7 g of sodium methoxide in 30 mL of anhydrous methanol. The resulting mixture was refluxed for 12 hrs. Filtration was carried out to remove solid. The solvent was removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. As shown in FIG. 7, NMR confirmed the product to be Bu.sub.2Sn(OMe).sub.2.

Example 8: Synthesis of Bu.SUB.2.Sn(OAc).SUB.2

(44) Sodium acetate was first made by adding 6 g acetic acid into a solution of 5.4 g of sodium methoxide in 30 mL of anhydrous methanol. This was then added into the mixture of 30 g of Bu.sub.2SnCl.sub.2 in 30 mL of anhydrous methanol. The resulting mixture was refluxed for 4 hrs. Filtration was carried out to remove solid. The solvent was removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. As shown in FIG. 8, NMR confirmed the product to be Bu.sub.2Sn(OAc).sub.2.

Example 9: Synthesis of Et.SUB.2.Sn(NMe.SUB.2.).SUB.2

(45) A 1 L flask was charged with 22 mL of 2.5M Butyllithium solution in hexane and 400 mL of anhydrous hexane. Me.sub.2NH gas was passed through the solution, and the reaction mixture was stirred for 1 h. The solution of 6.71 g of Et.sub.2SnCl.sub.2 in 100 mL of anhydrous benzene was then added and the mixture was stirred for 4 hrs. Filtration was carried out to remove any solid products. The solvent was removed under reduced pressure from the filtrate. The liquid product was purified by distillation under reduced pressure. As shown in FIG. 9, NMR confirmed the product to be Et.sub.2Sn(NMe.sub.2).sub.2.

Example 10: Synthesis of Me.SUB.2.Sn(NEt.SUB.2.).SUB.2

(46) In a 250 mL flask was charged 24 mL of 2.5M Butyllithium solution in hexane and 50 mL of anhydrous hexane, followed by the addition of 4.39 g of Et.sub.2NH. The reaction mixture was stirred for 2 hrs. The solution of 6.59 g of Me.sub.2SnCl.sub.2 in 100 mL of anhydrous ether was then added and the mixture was stirred for 4 hrs. Filtration was carried out to remove solid. The solvent was removed under reduced pressure. The liquid product was purified by distillation under reduced pressure. As shown in FIG. 10, NMR confirmed the product to be Me.sub.2Sn(NEt.sub.2).sub.2.

Example 11: Synthesis of Sn(Pyrrolidinyl).SUB.4

(47) Under inert atmosphere, a 100 mL round bottom flask was charged with 0.5 mL of Sn(NMe.sub.2).sub.4 and 25 mL of anhydrous hexane, followed by a drop-wise addition of 1.1 mL of pyrrolidene. After stirring the reaction mixture at room temperature for 2 h, the solvent was removed via distillation under reduced pressure. The residue remaining in the reaction flask was confirmed to be Sn(Pyrrolodinyl).sub.4 by NMR spectroscopy, as shown in FIG. 11.

Example 12: Synthesis of Bu.SUB.2.Sn(Pyrrolodinyl).SUB.2

(48) Under inert atmosphere, a 1 L round bottom flask was charged with 25 mL of 2.5M Butyllithium solution in hexane and 200 mL of anhydrous hexane, followed by a slow addition of 5.3 mL of pyrrolidene in 25 mL of anhydrous hexane. The reaction mixture was then stirred at room temperature for 1 h, and then placed into the ice bath. The solution of 9.46 g of Bu.sub.2SnCl.sub.2 in 50 mL of anhydrous hexane was then added to the flask, and the reaction mixture was left stirring at room temperature for 2 h. Filtration was carried out to remove any solid products. The solvent was removed under reduced pressure from the filtrate. As shown in FIG. 12, the product was confirmed to be Bu.sub.2Sn(Pyrrolodinyl).sub.2 by NMR spectroscopy.

Example 13: Synthesis of Et.SUB.2.Sn(Pyrrolodinyl).SUB.2

(49) Under inert atmosphere, a 1 L round bottom flask was charged with 5.3 mL of pyrrolidene and 200 mL of anhydrous pentane. Once the reaction flask was placed in the ice bath, 25 mL of 2.5M Butyllithium solution in hexane were slowly added to the reaction flask while stirring vigorously. The reaction mixture was then stirred at room temperature for 1 h, and then placed back into the ice bath. The solution of 7.7 g of Et.sub.2SnCl.sub.2 in 100 mL of anhydrous pentane and 20 mL of anhydrous benzene was then added to the flask, and the reaction mixture was left stirring at room temperature overnight. Filtration was carried out to remove any solid products. The solvent was removed under reduced pressure from the filtrate. Final product was purified via vacuum distillation. As shown in FIG. 13, the product is confirmed to be Et.sub.2Sn(Pyrrolodinyl).sub.2 by NMR spectroscopy.

Example 14: Synthesis of Me.SUB.2.Sn(NMe.SUB.2.).SUB.2

(50) Under inert atmosphere, a 1 L flask was charged with 25 mL of 2.5M Butyllithium solution in hexane and 400 mL of anhydrous hexane. The reaction flask was placed in the ice bath and Me.sub.2NH gas was passed through the solution until a white slushy solution was obtained (ca. 15 min). Afterwards the reaction mixture was stirred for 1 h at room temperature. The reaction flask was placed in the ice bath again and the solution of 6.7 g of Me.sub.2SnCl.sub.2 in 100 mL of anhydrous benzene was slowly added, and the mixture was stirred overnight at room temperature. Filtration was carried out to remove any solid products. The solvent was removed under reduced pressure from the filtrate. The liquid product was purified by distillation under reduced pressure. As shown in FIG. 14, the product is confirmed to be Me.sub.2Sn(NMe.sub.2).sub.2 by NMR spectroscopy.

Example 15: Synthesis of tBuSn(NMe.SUB.2.).SUB.3

(51)
Sn(NMe.sub.2).sub.4+tBuLi.fwdarw.tBuSn(NMe.sub.2).sub.3+LiNMe.sub.2  Formula IV

(52) Under inert atmosphere, a 5 L round bottom flask was charged with 100 mL of Sn(NMe.sub.2).sub.4 and ca. 3 L of anhydrous hexane. The mixture was stirred using a mechanical stirrer, and placed in the ethylene-glycol bath at −15° C. In the glovebox, a 1 L flask was loaded with 200 mL of 1.7M tert-butyllithium solution in anhydrous hexane, and ca. 200 mL of anhydrous hexane. The tBuLi solution was then slowly added to the reaction flask. The reaction mixture was stirred at room temperature for 3 h. The stirring was then stopped, and salts were left to precipitate out of the reaction mixture overnight. The liquid was cannulated into another 5 L round bottom flask. The solvents were removed via distillation, and 62 g of the final product were isolated by distillation under reduced pressure (120° C., 6.2×10.sup.−2 Torr). As shown in FIG. 15, the product was confirmed to be tBuSn(NMe.sub.2).sub.3 by NMR spectroscopy. 90% tBuSn(NMe.sub.2).sub.3 and 10% tBu.sub.2Sn(NMe.sub.2).sub.2.

(53) Similarly, complexes of the type RSn(NEtMe).sub.3 can be synthesized following the above procedure by reacting Sn(NEtMe).sub.4 with RLi, where R=Et, iPr, iBu, nPr
Sn(NEtMe).sub.4+RLi.fwdarw.RSn(NEtMe).sub.3+LiNEtMe  Formula V where R=Et, iPr, iBu, nPr

Example 16: Sn(NEtMe).SUB.4.+EtLi→EtSn(NEtMe).SUB.3.+LiNEtMe

(54) Under inert atmosphere, a 5 L round bottom flask was charged with 100 g of Sn(NEtMe).sub.4 and ca. 2.5 L of anhydrous hexane. The mixture was stirred using a mechanical stirrer, and placed in the ethylene-glycol bath at −15° C. In the glovebox, a 1 L flask was loaded with 655 mL of 0.5 M ethyllithium solution in anhydrous benzene, and ca. 200 mL of anhydrous benzene. The EtLi solution was then slowly added to the reaction flask. The reaction mixture was stirred at room temperature for 3 h. The stirring was then stopped, and salts were left to precipitate out of the reaction mixture overnight. The liquid was cannulated into another 5 L round bottom flask. The solvents were removed via distillation, and the final product isolated via distillation under reduced pressure.

Example 17: Sn(NEtMe).SUB.4.+iPrLi→iPrSn(NEtMe).SUB.3.+LiNEtMe

(55) Under inert atmosphere, a 5 L round bottom flask was charged with 100 g of Sn(NEtMe).sub.4 and ca. 2.5 L of anhydrous hexane. The mixture was stirred using a mechanical stirrer, and placed in the ethylene-glycol bath at −15° C. In the glovebox, a 1 L flask was loaded with 468 mL of 0.7 M isopropyllithium solution in anhydrous pentane, and ca. 200 mL of anhydrous hexane. The iPrLi solution was then slowly added to the reaction flask. The reaction mixture was stirred at room temperature for 3 h. The stirring was then stopped, and salts were left to precipitate out of the reaction mixture overnight. The liquid was cannulated into another 5 L round bottom flask. The solvents were removed via distillation, and the final product isolated via distillation under reduced pressure.

Example 18: Sn(NEtMe).SUB.4.+iBuLi→iBuSn(NEtMe).SUB.3.+LiNEtMe

(56) Under inert atmosphere, a 5 L round bottom flask was charged with 100 g of Sn(NEtMe).sub.4 and ca. 3 L of anhydrous hexane. The mixture was stirred using a mechanical stirrer, and placed in the ethylene-glycol bath at −15° C. In the glovebox, a 1 L flask was loaded with 193 mL of 1.7 M isobutyllithium solution in anhydrous heptane, and ca. 200 mL of anhydrous hexane. The iBuLi solution was then slowly added to the reaction flask. The reaction mixture was stirred at room temperature for 3 h. The stirring was then stopped, and salts were left to precipitate out of the reaction mixture overnight. The liquid was cannulated into another 5 L round bottom flask. The solvents were removed via distillation, and the final product isolated via distillation under reduced pressure.

Example 19: Sn(NEtMe).SUB.4.+nPrLi→nPrSn(NEtMe).SUB.3.+LiNEtMe

(57) Under inert atmosphere, a 5 L round bottom flask was charged with 100 g of Sn(NEtMe).sub.4 and ca. 3 L of anhydrous hexane. The mixture was stirred using a mechanical stirrer, and placed in the ethylene-glycol bath at −15° C. In the glovebox, a 1 L flask was loaded with 193 mL of 1.7 M n-propyllithium solution in anhydrous heptane, and ca. 200 mL of anhydrous hexane. The nPrLi solution was then slowly added to the reaction flask. The reaction mixture was stirred at room temperature for 3 h. The stirring was then stopped, and salts were left to precipitate out of the reaction mixture overnight. The liquid was cannulated into another 5 L round bottom flask. The solvents were removed via distillation, and the final product isolated via distillation under reduced pressure.

Example 20: Comparative Reactivity Tests

(58) a)

(59) To Sn(NMe.sub.2).sub.4 was added water. Reaction took place spontaneously. The clear Sn(NMe.sub.2).sub.4 turned cloudy and a white solid formed. To Sn(NMe.sub.2).sub.4 was added anhydrous ethanol. The mixture warmed up and NMR confirmed the complete replacement of —NMe.sub.2 group by —OEt group. More ethanol was added and NMR was carried out to further confirm the completion of the reaction (FIG. 16).
b) To Me.sub.3SnNMe.sub.2 was added water. NMR indicated that no reaction took place. The mixture was heated at 50° C. for 1 hr. NMR showed that reaction took place (FIG. 17). To Me.sub.3SnNMe.sub.2 was added anhydrous methanol NMR indicated that no reaction took place. The mixture was heated at 50° C. for 1 hr. The clear solution turned cloudy. NMR confirmed that reaction had taken place.
c) To Bu.sub.2Sn(OAc).sub.2 was added water. Reaction took place spontaneously. The clear Bu.sub.2Sn(OAc).sub.2 turned cloudy and a white solid formed. To Bu.sub.2Sn(OAc).sub.2 was added anhydrous methanol. NMR showed that no reaction took place (FIG. 18).
d) To Bu.sub.2Sn(OMe).sub.2 was added water. Reaction took place spontaneously. The clear Bu.sub.2Sn(OMe).sub.2 turned cloudy and a white solid formed. To Bu.sub.2Sn(OMe).sub.2 was added acetic acid. NMR shows that some —OMe group has been replaced by —OAc group (FIG. 19).
e) To Bu.sub.2Sn(NMe.sub.2).sub.2 was added water. Reaction took place spontaneously. The clear Bu.sub.2Sn(NMe.sub.2).sub.2 turned cloudy and a white solid formed. To Bu.sub.2Sn(NMe.sub.2).sub.2 was added Methanol. NMR shows that some —NMe.sub.2 group has been replaced by —OMe group (FIG. 20).

Example 21: Thermal Stability Tests

(60) Thermal stability tests of compounds of Formula I were carried out in sealed glass ampoules, which were heated at a set temperature for 1 hr. NMR was performed to see if there had been any thermal decomposition. A visual check was also used, looking for solid formation after heat treatment. FIG. 21 shows NMR of Me.sub.4Sn before and after heating at 200° C. There was no significant change after heating at 200° C. for 1 hr based on both NMR and visual check.

(61) FIG. 22 shows NMR of Et.sub.2Sn(NMe.sub.2).sub.2 before and after heating at 200° C. There was no significant change after heating at 200° C. for 1 hr based on both NMR and visual check.

(62) FIG. 23 shows NMR of Me.sub.2Sn(NMe.sub.2).sub.2 before and after heating at 150° C. There was no significant change after heating at 150° C. for 24 hr based on both NMR and visual check.

(63) FIG. 24 shows the decomposition temperature of representative compounds of Formula I.

(64) These results demonstrate that compounds of Formula I are thermally stable, showing that delivery of the compound to the deposition chamber will take place without observable decomposition occurring.

(65) Multistage Distillation

(66) Various forms of multistage distillation are known in the chemical manufacturing industry, but have not been employed for the purification of organometallic materials that include tetramethyl tin or other compounds of Formula I.

(67) As illustrated by the schematic shown in FIG. 25, multiple-effect or multistage distillation (MED) is a distillation process often used for sea water desalination. It consists of multiple stages or “effects”. (In schematic in FIG. 25 the first stage is at the top. Pink areas are vapor, lighter blue areas are liquid feed material. The turquoise represents condensate. It is not shown how feed material enters other stages than the first, however those should be readily understood. F—feed in. S—heating steam in. C—heating steam out. W—purified material (condensate) out. R—waste material out. O—coolant in. P—coolant out. VC is the last-stage cooler.) In each stage the feed material is heated by steam in tubes. Some of the feed material evaporates, and this steam flows into the tubes of the next stage, heating and evaporating more of the distillate. Each stage essentially reuses the energy from the previous stage.

(68) The plant can be seen as a sequence of closed spaces separated by tube walls, with a heat source at one end and a heat sink at the other. Each space consists of two communicating subspaces, the exterior of the tubes of stage n and the interior of the tubes in stage n+1. Each space has a lower temperature and pressure than the previous space, and the tube walls have intermediate temperatures between the temperatures of the fluids on each side. The pressure in a space cannot be in equilibrium with the temperatures of the walls of both subspaces; it has an intermediate pressure. As a result, the pressure is too low or the temperature too high in the first subspace, and the feed material evaporates. In the second subspace, the pressure is too high or the temperature too low, and the vapor condenses. This carries evaporation energy from the warmer first subspace to the colder second subspace. At the second subspace the energy flows by conduction through the tube walls to the colder next space.

(69) As shown by Table 2 below, purification of SnMe.sub.4 by multistage distillation results in a compound having significantly lower levels of impurities compared to that purified by conventional means.

(70) TABLE-US-00001 TABLE 2 Single Single Average Delta Multi stage stage single vs Single Multistage option 1 option 2 stage ppb % Element ppb ppb ppb ppb difference Ag 5 10 5 7.5 −33% Al 5 40 20 30 −83% As 50 50 100 75 −33% Au 10 10 5 7.5  33% B 40 70 10 40  0% Be 1 1 5 3 −67% Bi 1 2 5 3.5 −71% Ca 80 270 100 185 −57% Cd 1 1 5 3 −67% Co 0 1 5 3 −100%  Cr 2 3 5 4 −50% Cu 4 12 5 8.5 −53% Fe 11 31 10 20.5 −46% Hf 0 0 5 2.5 −100%  K 30 30 20 25  20% Li 2 5 50 27.5 −93% Mg 8 35 50 42.5 −81% Mn 0.5 0.5 5 2.75 −82% Mo 0.5 1.8 5 3.4 −85% Na 200 200 100 150  33% Nb 0.5 0.5 5 2.75 −82% N 150 150 5 77.5  94% Pb 0.4 2.1 2 2.05 −80% Pd 0.5 0.5 5 2.75 −82% Pt 2 2 5 3.5 −43% Rb 1 1 5 3 −67% Re 0.5 0.5 5 2.75 −82% Rh 0.5 0.5 5 2.75 −82% Ru 0.5 0.5 5 2.75 −82% Sb 20 120 250 185 −89%

(71) The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening.

(72) The recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein.

(73) All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not impose a limitation on the scope of the invention unless otherwise claimed. The various embodiments and elements can be interchanged or combined in any suitable manner as necessary.

(74) No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

(75) It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. There is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.