U.S. patent application number 17/213328 was filed with the patent office on 2021-07-15 for organometallic compounds and purification of such organometallic compounds.
This patent application is currently assigned to SEASTAR CHEMICALS ULC. The applicant listed for this patent is SEASTAR CHEMICALS ULC. Invention is credited to Cunhai DONG, Diana FABULYAK, Wesley GRAFF, Rajesh ODEDRA.
Application Number | 20210214379 17/213328 |
Document ID | / |
Family ID | 1000005480112 |
Filed Date | 2021-07-15 |
United States Patent
Application |
20210214379 |
Kind Code |
A1 |
ODEDRA; Rajesh ; et
al. |
July 15, 2021 |
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.
Inventors: |
ODEDRA; Rajesh; (West
Timperely, GB) ; DONG; Cunhai; (Victoria, CA)
; FABULYAK; Diana; (Victoria, CA) ; GRAFF;
Wesley; (Singapore, SG) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SEASTAR CHEMICALS ULC |
Sidney |
|
CA |
|
|
Assignee: |
SEASTAR CHEMICALS ULC
Sidney
CA
|
Family ID: |
1000005480112 |
Appl. No.: |
17/213328 |
Filed: |
March 26, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16834361 |
Mar 30, 2020 |
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17213328 |
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16442930 |
Jun 17, 2019 |
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16834361 |
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PCT/CA2018/050933 |
Jul 31, 2018 |
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16442930 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03F 7/09 20130101; G03F
7/167 20130101; C07F 7/2284 20130101; G03F 7/161 20130101 |
International
Class: |
C07F 7/22 20060101
C07F007/22; G03F 7/09 20060101 G03F007/09; G03F 7/16 20060101
G03F007/16 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 2, 2017 |
CA |
2975104 |
Claims
1-19. (canceled)
20. A high purity organometallic compound having a purity greater
than 95%, the high purity organometallic compound being a compound
of Formula I: R.sub.x--Sn-A.sub.4-x Formula I wherein: A is
selected from the group consisting of (YaR'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.
21. The high purity organometallic compound of claim 20, wherein
the purity is greater than 98%.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of copending application
Ser. No. 16/442,930, filed Jun. 17, 2019, which is a Continuation
of PCT International Patent Application No. PCT/CA2018/050933 filed
Jul. 31, 2018, which claims priority to Canadian Application No.
2975104 filed Aug. 2, 2017, all of which are incorporated by
reference in their entireties.
TECHNICAL FIELD
[0002] The disclosure relates to organometallic compounds useful
for the deposition of high purity tin oxide and to the purification
of such organometallic compounds.
BACKGROUND
[0003] The semiconductor industry is producing more and more
components having smaller and smaller feature sizes. The production
of such semiconductor devices reveals new design and manufacturing
challenges which must be addressed in order to maintain or improve
semiconductor device performance. The production of semiconductor
wiring stacks with high density, high yield, good signal integrity
as well as suitable power delivery also presents challenges.
[0004] Lithography is a critical pattern transfer technique widely
used in the fabrication of a variety of electronic devices which
contain microstructures, such as semiconductor devices and liquid
crystal devices. As device structures are miniaturized, masking
patterns used in the lithography process must be optimized to
accurately transfer patterns to the underlying layers.
[0005] Multiple-pattern lithography represents a class of
technologies developed for photolithography in order to enhance the
feature density of semiconductor devices. Double-patterning, a
subset of multiple-patterning, employs multiple masks and
photolithographic steps to create a particular level of a
semiconductor device. With benefits such as tighter pitches and
narrower wires, double-patterning alters relationships between
variables related to semiconductor device wiring and wire quality
to sustain performance.
[0006] Recently, a liquid immersion lithography method has been
reported, which purports to address some of the issues facing the
industry. By employing liquid immersion lithography, a resist
pattern having a higher resolution and an excellent depth of focus
can be formed at a low cost, using a lens mounted on existing
exposure systems, such that the liquid immersion lithography has
attracted considerable attention.
[0007] As a result of moving to immersion lithography and
multi-patterning, the need exists for a new class of conformally
deposited materials to be deposited on top of photo resist, BARC,
and other traditional masking layers. This new conformal deposition
layer can serve 2 major functions: [0008] 1) It can act as a
transparent protection layer (or "mask") to prevent chemical attack
by the immersion lithography fluid. In this case, the conformal
layer needs to be transparent, and be able to integrate with the
lithography process without adverse patterning and exposure issues.
[0009] 2) It can have a higher etch selectivity than prior art and
traditional films such as amorphous carbon (which become more
opaque with increasing thickness). For example, multi-patterning
processes may require thicker (>10,000 A), and therefore more
opaque, amorphous carbon layers in order to achieve the necessary
etch protection. To achieve a similar etch resistance, metal oxide
conformal films can remain transparent while maintaining the
required etch selectivity during the plasma etch process.
[0010] High purity of the reactant gases used in these processes
are required, in order to ensure consistent chemical makeup for
smoothness, etch and deposition characteristics, 100% step
coverage/conformality requirement.
[0011] The purity of the film produced is also required to be high,
due to the use of the film as a resist protection layer during etch
or during litho immersion processing. Impurities in the film can
have adverse reactions, chemically or optically, which interfere
with the pattern quality and which can affect critical dimensions
on the device features as well as these impurities leaching into or
contaminating adjacent layers, which can result in degradation of
the integrated device performance.
[0012] Conventional resist compositions cannot always be used in
liquid immersion lithography processes, for a variety of reasons.
For example, in the liquid immersion lithography process, the
resist film is directly in contact with the refractive index liquid
(immersion liquid) during the exposure, and hence the resist film
is vulnerable to attack by the liquid. Resist compositions suitable
for use in liquid immersion lithography processes must also be
transparent to the exposure light. Further, conventional resist
compositions may not be able to achieve a satisfactory resolution
of pattern in liquid immersion lithography due to a change in their
properties by the liquid, despite their utility in lithography
employing the exposure through a layer of air.
[0013] Thus, there remains a need for improved transparent resist
protection layers which can meet the increased requirements of the
industry. Further, higher selectivity ALD films are needed for
multi-patterning, as outlined above.
SUMMARY
[0014] Disclosed herein are compounds useful for the deposition of
high purity tin oxide. Films deposited using such compounds
demonstrate high conformality, high etch selectivity, high hardness
and modulus, and are optically transparent.
[0015] Compounds include those of Formula I, below:
R.sub.x--Sn-A.sub.4-x Formula I
wherein: [0016] A is selected from the group consisting of
(Y.sub.aR'.sub.z) and a 3- to 7-membered N-containing heterocyclic
group; [0017] each R group is independently selected from the group
consisting of an alkyl or aryl group having from 1 to 10 carbon
atoms; [0018] each R' group is independently selected from the
group consisting of an alkyl, acyl or aryl group having from 1 to
10 carbon atoms; [0019] x is an integer from 0 to 4; [0020] a is an
integer from 0 to 1; [0021] Y is selected from the group consisting
of N, O, S, and P; and [0022] z is 1 when Y is O, S or when Y is
absent and z is 2 when Y is N or P
[0023] The use of compounds of Formula I 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, high hardness and modulus,
and >99% step coverage (i.e. high conformality) over device
features and topography.
[0024] Also disclosed is the purification of compounds of Formula I
by multistage distillation. Such purification yields so-called
"ultra-pure" compounds having higher assay purity and much lower
levels of metallic impurities compared to compounds purified by
conventional means. The use of such ultra-pure compounds in the
processes disclosed herein results in films having improved
properties compared to those known in the art. For example, the
films may have improved hermetic properties, low impurities and
improvements in the associated yield loss and long term reliability
failures resulting from such impurities. Multistage distillation
may be carried out in the form of packed columns, stage
distillation columns employing trays, multiple distillation
columns, or other types of multistage distillation.
[0025] The tin oxide film so produced may also exhibit high etch
selectivity verses traditional masking and conformal layers used in
multilayer patterning integration techniques, resulting in a
thinner film requirement as compared to traditional films such as
amorphous carbon, boron doped carbon, etc.
[0026] In an embodiment, in the organometallic compound of Formula
I, A is selected from the group consisting of an (NR'.sub.2) group
and a 3- to 7-membered N-containing heterocyclic group. In an
embodiment, A is an (NR'.sub.2) group. In an embodiment, A is a 3-
to 7-membered N-containing heterocyclic group. In an embodiment, A
is a pyrrolidinyl group. In an embodiment, A.sub.4-x is
(NMe.sub.2).sub.2 or (NEtMe).sub.2.
[0027] In other embodiments R and R' group is an independently
selected alkyl group having from 1 to 10 carbon atoms. It is
contemplated that each R and R' group may be an independently
selected alkyl group having from 1 to 6 carbon atoms. In
embodiments, each R and R' group is an independently selected alkyl
group having from 1 to 4 carbon atoms. In embodiments, R and R' is
independently selected from the group consisting of methyl, ethyl,
propyl, iso-propyl, tert-butyl, iso-butyl and n-butyl. In
embodiments R and R' represent different alkyl groups.
[0028] In an embodiment, the 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, i-PrSn(NEtMe).sub.3,
n-Pr(NEtMe).sub.3, EtSN(NEtMe).sub.3, i-BuSn(NEtMe).sub.3,
Et.sub.2Sn(NEtMe).sub.2, Me.sub.2Sn(NEtMe).sub.2, Sn(NEtMe).sub.4,
Bu.sub.2Sn(NEtMe).sub.2, Et.sub.2Sn(NMe.sub.2).sub.2,
Me.sub.2Sn(NEt.sub.2).sub.2, Sn(Pyrrolidinyl).sub.4 and
Bu.sub.2Sn(Pyrrolidinyl).sub.2.
[0029] In embodiments, the 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, Et.sub.2Sn(NMe.sub.2).sub.2,
Me.sub.2Sn(NEt.sub.2).sub.2, Sn(Pyrrolidinyl).sub.4, and
Bu.sub.2Sn(Pyrrolidinyl).sub.2.
[0030] In embodiments, the compound of Formula I is selected from
the group consisting of Me.sub.2Sn(NEtMe).sub.2 and
Me.sub.2Sn(NMe.sub.2).sub.2.
[0031] In embodiments, the compound of Formula I is
Me.sub.2Sn(NMe.sub.2).sub.2.
[0032] In embodiments, a composition is provided that comprises the
organometallic compound of any of the disclosed compounds and
another organometallic compound containing Sn. The another
organometallic compound may be a compound of Formula I.
[0033] In various embodiments, another organometallic compound is
selected from the group consisting of MeSn(NMe.sub.2).sub.3 and
Sn(NMe.sub.2).sub.4.
[0034] In an embodiment, a method of using multistage distillation
to purify the organometallic compounds disclosed. In an embodiment,
2 to 20 stages are required to reduce metal contamination to <1
ppm. In an embodiment, 2 to 20 stages are required to reduce metal
contamination to <100 ppb. In an embodiment, 2 to 20 stages are
required to reduce metal contamination to <10 ppb. In an
embodiment, 2 to 20 stages are required to reduce metal
contamination to 1 ppb or less.
[0035] The foregoing and other features of the invention and
advantages of the present invention will become more apparent in
light of the following detailed description of the preferred
embodiments, as illustrated in the accompanying figures. As will be
realized, the invention is capable of modifications in various
respects, all without departing from the invention. Accordingly,
the drawings and the description are to be regarded as illustrative
in nature, and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 shows the NMR spectrum of Me.sub.3SnNMe.sub.2.
[0037] FIG. 2 shows the NMR spectrum of Sn(NMe.sub.2).sub.4.
[0038] FIG. 3 shows the NMR spectrum of
Me.sub.2Sn(NEtMe).sub.2.
[0039] FIG. 4 shows the NMR spectrum of
Bu.sub.2Sn(NMe.sub.2).sub.2.
[0040] FIG. 5 shows the NMR spectrum of Me.sub.2SnEt.sub.2.
[0041] FIG. 6 shows the NMR spectrum of Me.sub.4Sn.
[0042] FIG. 7 shows the NMR spectrum of Bu.sub.2Sn(OMe).sub.2.
[0043] FIG. 8 shows the NMR spectrum of Bu.sub.2Sn(OAc).sub.2.
[0044] FIG. 9 shows the NMR spectrum of
Et.sub.2Sn(NMe.sub.2).sub.2.
[0045] FIG. 10 shows the NMR spectrum of
Me.sub.2Sn(NEt.sub.2).sub.2.
[0046] FIG. 11 shows the NMR spectrum of
Sn(Pyrrolodinyl).sub.4.
[0047] FIG. 12 shows the NMR spectrum of
Bu.sub.2Sn(Pyrrolodinyl).sub.2.
[0048] FIG. 13 shows the NMR spectrum of
Et.sub.2Sn(Pyrrolodinyl).sub.2.
[0049] FIG. 14 shows the NMR spectrum of
Me.sub.2Sn(NMe.sub.2).sub.2.
[0050] FIG. 15 shows the NMR spectrum of tBuSn(NMe.sub.2).sub.3
[0051] FIG. 16 shows the NMR of the reaction of (NMe.sub.2).sub.4Sn
with ethanol.
[0052] FIG. 17 shows the NMR of the reaction of Me.sub.3SnNMe.sub.2
with water.
[0053] FIG. 18 shows the NMR of the reaction of
Bu.sub.2Sn(OAc).sub.2 with methanol.
[0054] FIG. 19 shows the NMR of the reaction of
Bu.sub.2Sn(OMe).sub.2 with acetic acid.
[0055] FIG. 20 shows the NMR of the reaction of
Bu.sub.2Sn(NMe.sub.2).sub.2 with methanol.
[0056] FIG. 21 shows the NMR of Me.sub.4Sn before and after heating
at 200.degree. C.
[0057] FIG. 22 shows the NMR of Et.sub.2Sn(NMe.sub.2).sub.2 before
and after heating at 200.degree. C.
[0058] FIG. 23 shows the NMR of Me.sub.2Sn(NMe.sub.2).sub.2 before
and after heating at 150.degree. C.
[0059] FIG. 24 shows the decomposition temperatures of illustrative
compounds of Formula I.
[0060] FIG. 25 shows a schematic of a multistage distillation
apparatus.
DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS
[0061] Disclosed are organometallic compounds of Formula I,
below:
R.sub.x--Sn-A.sub.4-x Formula I
wherein: [0062] A is selected from the group consisting of
(Y.sub.aR'.sub.z) and a 3- to 7-membered N-containing heterocyclic
group; [0063] each R group is independently selected from the group
consisting of an alkyl or aryl group having from 1 to 10 carbon
atoms; [0064] each R' group is independently selected from the
group consisting of an alkyl, acyl or aryl group having from 1 to
10 carbon atoms; [0065] x is an integer from 0 to 4; [0066] a is an
integer from 0 to 1; [0067] Y is selected from the group consisting
of N, O, S, and P; and [0068] z is 1 when Y is O, S or when Y is
absent and z is 2 when Y is N or P
[0069] 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.
[0070] 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.
[0071] 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.
[0072] 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.
[0073] 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.
[0074] 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.
[0075] 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.
[0076] 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.
[0077] 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.
[0078] 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.3Sn(NMe.sub.2)
[0079] 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
[0080] 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.2Sn(NEtMe).sub.2
[0081] 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.degree. C. at 9.8.times.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.2Sn(NMe.sub.2).sub.2
[0082] 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.2SnEt.sub.2
[0083] 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
0.1MHCl 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.4Sn
[0084] 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.2Sn(OMe).sub.2
[0085] 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.2Sn(OAc).sub.2
[0086] 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.2Sn(NMe.sub.2).sub.2
[0087] 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.2Sn(NEt.sub.2).sub.2
[0088] 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
[0089] 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.2Sn(Pyrrolodinyl).sub.2
[0090] 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.2Sn(Pyrrolodinyl).sub.2
[0091] 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.2Sn(NMe.sub.2).sub.2
[0092] 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
[0093]
Sn(NMe.sub.2).sub.4+tBuLi.fwdarw.tBuSn(NMe.sub.2).sub.3+LiNMe.sub.-
2 Formula IV
[0094] 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.degree. 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.degree. C., 6.2.times.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.
[0095] 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
[0096] where R=Et, iPr, iBu, nPr
Example 16:
Sn(NEtMe).sub.4+EtLi.fwdarw.EtSn(NEtMe).sub.3+LiNEtMe
[0097] 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.degree. 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.fwdarw.iPrSn(NEtMe).sub.3+LiNEtMe
[0098] 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.degree. 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.fwdarw.iBuSn(NEtMe).sub.3+LiNEtMe
[0099] 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.degree. 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.fwdarw.nPrSn(NEtMe).sub.3+LiNEtMe
[0100] 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.degree. 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
[0101] a) [0102] 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. [0103] 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) [0104] To
Me.sub.3SnNMe.sub.2 was added water. NMR indicated that no reaction
took place. The mixture was heated at 50.degree. C. for 1 hr. NMR
showed that reaction took place (FIG. 17). [0105] To
Me.sub.3SnNMe.sub.2 was added anhydrous methanol NMR indicated that
no reaction took place. The mixture was heated at 50.degree. C. for
1 hr. The clear solution turned cloudy. NMR confirmed that reaction
had taken place. c) [0106] 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.
[0107] To Bu.sub.2Sn(OAc).sub.2 was added anhydrous methanol. NMR
showed that no reaction took place (FIG. 18). d) [0108] 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. [0109] 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) [0110] 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.
[0111] 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
[0112] 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.degree. C. There was no
significant change after heating at 200.degree. C. for 1 hr based
on both NMR and visual check.
[0113] FIG. 22 shows NMR of Et.sub.2Sn(NMe.sub.2).sub.2 before and
after heating at 200.degree. C. There was no significant change
after heating at 200.degree. C. for 1 hr based on both NMR and
visual check.
[0114] FIG. 23 shows NMR of Me.sub.2Sn(NMe.sub.2).sub.2 before and
after heating at 150.degree. C. There was no significant change
after heating at 150.degree. C. for 24 hr based on both NMR and
visual check.
[0115] FIG. 24 shows the decomposition temperature of
representative compounds of Formula I.
[0116] 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.
Multistage Distillation
[0117] 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.
[0118] 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.
[0119] 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.
[0120] 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.
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%
[0121] 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.
[0122] 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.
[0123] 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.
[0124] No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the invention.
[0125] 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.
* * * * *