U.S. patent application number 11/658368 was filed with the patent office on 2008-12-04 for copper (i) complexes for deposition of copper films by atomic layer deposition.
Invention is credited to Bradley Alexander Zak, Kyung-Ho Park, Jeffery Scott Thompson.
Application Number | 20080299322 11/658368 |
Document ID | / |
Family ID | 35335712 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080299322 |
Kind Code |
A1 |
Alexander Zak; Bradley ; et
al. |
December 4, 2008 |
Copper (I) Complexes for Deposition of Copper Films by Atomic Layer
Deposition
Abstract
The present invention relates to novel 1,3-diimine copper
complexes and the use of 1,3-diimine copper complexes for the
deposition of copper on substrates or in or on porous solids in an
Atomic Layer Deposition process.
Inventors: |
Alexander Zak; Bradley;
(Wilmington, DE) ; Thompson; Jeffery Scott;
(Wilmington, DE) ; Park; Kyung-Ho; (Wilmington,
DE) |
Correspondence
Address: |
Dalickas Gail A;E.I. DU PONT NEMOURS AND COMPANY
4417 Lancaster Pike
Wilmington
DE
19805
US
|
Family ID: |
35335712 |
Appl. No.: |
11/658368 |
Filed: |
July 29, 2005 |
PCT Filed: |
July 29, 2005 |
PCT NO: |
PCT/US2005/027019 |
371 Date: |
January 24, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60592785 |
Jul 30, 2004 |
|
|
|
60592816 |
Jul 30, 2004 |
|
|
|
Current U.S.
Class: |
427/437 ;
257/E21.171; 548/402 |
Current CPC
Class: |
C07D 401/06 20130101;
H01L 21/28562 20130101; C23C 16/45553 20130101; C07D 207/20
20130101; C23C 16/18 20130101 |
Class at
Publication: |
427/437 ;
548/402 |
International
Class: |
B05D 1/18 20060101
B05D001/18; C07F 1/08 20060101 C07F001/08 |
Claims
1. A process for forming copper deposits on a substrate comprising:
a. contacting a substrate with a copper complex, (I), to form a
deposit of a copper complex on the substrate; and ##STR00004## b.
contacting the deposited copper complex with a reducing agent,
wherein L is selected from C.sub.2-C.sub.15 olefins, C2-C,.sub.5
alkynes, nitriles, aromatic heterocycles, and phosphines; R.sup.1
and R.sup.4 are independently selected from hydrogen, methyl,
ethyl, propyl, isopropyl, isobutyl, neopentyl, and C.sub.3-C.sub.5
alkylene; R.sup.2, R.sup.3 and R.sup.5 are independently selected
from hydrogen, fluorine, trifluoromethyl, phenyl, C.sub.1-C.sub.10
alkyl and C.sub.3-C.sub.5 alkylene, with the proviso that at least
one of (R.sup.1, R.sup.2) and (R.sup.3, R.sup.4) taken together is
--(CR.sup.6R.sup.7).sub.n--, where R.sup.6 and R.sup.7 are
independently selected from hydrogen, fluorine, trifluoromethyl,
C.sub.1-C.sub.5 alkyl, and C.sub.1-C.sub.5 alkyl ester, and n is 3,
4 or 5; the reducing agent is selected from 9-BBN
(9-borabicyclo[3.3.1]nonane); diborane; boranes of the form
BR.sub.xH.sub.3-x, where x=0, 1 or 2, and R is independently
selected from phenyl and C.sub.1-C.sub.10 alkyl groups;
dihydrobenzofuran; pyrazoline; disilane; silanes of the form
SiR'.sub.yH.sub.4-y, where y=0, 1, 2 or 3, and R' is independently
selected from phenyl and C.sub.1-C.sub.10 alkyl groups; and
germanes of the form GeR''.sub.zH.sub.4-z, where z=0, 1, 2, or 3,
and R' is independently selected from phenyl and C.sub.1-C.sub.10
alkyl groups.
2. The process of claim 1, wherein R.sup.5 is hydrogen.
3. The process of claim 1 or claim 2, wherein R.sup.1 and R.sup.2
taken together are --(CH.sub.2).sub.n--, where n is 3, 4, or 5.
4. The process of claim 3, wherein R.sup.3 and R.sup.4 taken
together are --(CH.sub.2).sub.n--, where n is 3, 4, or 5.
5. The process of claim 3, wherein R.sup.3 is methyl and R.sup.4 is
H.
6. The process of claim 1, wherein L is vinyltrimethylsilane.
7. The process of claim 1, wherein the substrate is selected from
copper, silicon wafers and silicon dioxide coated with a barrier
layer.
8. The process of claim 1, wherein the substrate is exposed to a
vapor of the copper complex.
9. The process of claim 1, wherein the deposition is carried out at
a temperature of 0 to 200.degree. C.
10. The process of claim 1, wherein the reducing agent is silane or
diethylsilane.
11. A copper complex, (I), ##STR00005## wherein L is selected from
C.sub.2-C.sub.15 olefins, C.sub.2-C.sub.15 alkynes, nitriles,
aromatic heterocycles, and phosphines; R.sup.1 and R.sup.4 are
independently selected from hydrogen, methyl, ethyl, propyl,
isopropyl, isobutyl, neopentyl, and C.sub.3-C.sub.5 alkylene;
R.sup.2, R.sup.3 and R.sup.5 are independently selected from
hydrogen, fluorine, trifluoromethyl, phenyl, C.sub.1-C.sub.10 alkyl
and C.sub.3-C.sub.5 alkylene; with the proviso that at least one of
(R.sup.1, R.sup.2) and (R.sup.3, R.sup.4) taken together is
--(CR.sup.6R.sup.7).sub.n--, where R.sup.6 and R.sup.7 are
independently selected from hydrogen, fluorine, trifluoromethyl,
C.sub.1-C.sub.5 alkyl, and C.sub.1-C.sub.5 alkyl ester, and n is 3,
4 or 5.
12. The copper complex (I) of claim 11, wherein L is
vinyltrimethylsilane; R.sup.1 and R.sup.5 are hydrogen' R.sup.2 is
methyl, (R.sup.3, R.sup.4) taken together is --(CH.sub.2).sub.n--
and n is 3.
13. An article produced by contacting a substrate with a copper
complex of claim 11.
14. The article of claim 13, wherein the substrate is selected from
copper, silicon wafers, and silicon dioxide coated with a barrier
layer.
15. The article of claim 14, wherein the barrier layer is selected
from tantalum, tantalum nitride, titanium, titanium nitride,
tantalum silicon nitride, titanium silicon nitride, tantalum carbon
nitride, and niobium nitride.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to novel 1,3-diimine copper
complexes. The invention also relates to processes for forming
copper deposits on substrates or in or on porous solids, using the
1,3-diimine copper complexes.
BACKGROUND
[0002] Atomic layer deposition (ALD) processes are useful for the
creation of thin films, as described by M. Ritala and M. Leskela in
"Atomic Layer Deposition" in Handbook of Thin Film Materials, H. S.
Nalwa, Editor, Academic Press, San Diego, 2001, Volume 1, Chapter
2. Such films, especially metal and metal oxide films, are critical
components in the manufacture of electronic circuits and
devices.
[0003] In an ALD process for depositing copper films, a copper
precursor and a reducing agent are alternatively introduced into a
reaction chamber. After the copper precursor is introduced into the
reaction chamber and allowed to adsorb onto a substrate, the excess
(unadsorbed) precursor vapor is pumped or purged from the chamber.
This process is followed by introduction of a reducing agent that
reacts with the copper precursor on the substrate surface to form
copper metal and a free form of the ligand. This cycle can be
repeated if needed to achieve the desired film thickness.
[0004] This process differs from chemical vapor deposition (CVD) in
the decomposition chemistry of the metal complex. In a CVD process,
the complex undergoes pyrolytic decomposition on contact with the
surface to give the desired film. In an ALD process, the complex is
not completely decomposed to metal on contact with the surface.
Rather, formation of the metal film takes place on introduction of
a second reagent, which reacts with the deposited metal complex. In
the preparation of a copper film from a copper(I) complex, the
second reagent is a reducing agent. Advantages of an ALD process
include the ability to control the film thickness and improved
conformality of coverage because of the self-limiting adsorption of
the precursor to the substrate surface in the first step of the
process.
[0005] The ligands used in the ALD processes must also be stable
with respect to decomposition and be able to desorb from the
complex in a metal-free form. Following reduction of the copper,
the ligand is liberated and must be removed from the surface to
prevent its incorporation into the metal layer being formed.
[0006] S. G. McGeachin, Canadian Journal of Chemistry, 46,
1903-1912 (1968), describes the synthesis of 1,3-diimines and metal
complexes of these ligands, including bis-chelate or homoleptic
complexes of the form ML.sub.2.
[0007] U.S. Pat. No. 6,464,779 discloses a Cu atomic layer CVD
process that requires treatment of a copper precursor containing
both oxygen and fluorine with an oxidizing agent to form copper
oxide, followed by treatment of the surface with a reducing
agent.
[0008] WO 2004/036624 describes a two-step ALD process for forming
copper layers comprising forming a copper oxide layer from a
non-fluorine containing copper precursor on a substrate and
reducing the copper oxide layer to form a copper layer on the
substrate. Copper alkoxides, copper .beta.-diketonates and copper
dialkylamides are preferred copper precursors. The reducing agent
is a hydrogen (H.sub.2) containing gas.
[0009] US 2003/0135061 discloses a dimeric copper(I) precursor
which can be used to deposit metal or metal-containing films on a
substrate under ALD or CVD conditions.
[0010] WO 2004/046417 describes the use of dimeric copper (I)
complexes comprising amidinate ligands for use in an ALD
process.
SUMMARY OF THE INVENTION
[0011] One aspect of this invention is a process for forming copper
deposits on a substrate comprising: [0012] a. contacting a
substrate with a copper complex, (I), to form a deposit of a copper
complex on the substrate; and
[0012] ##STR00001## [0013] b. contacting the deposited copper
complex with a reducing agent, wherein L is selected from
C.sub.2-C.sub.15 olefins, C.sub.2-C.sub.15 alkynes, nitriles,
aromatic heterocycles, and phosphines; R.sup.1 and R.sup.4 are
independently selected from hydrogen, methyl, ethyl, propyl,
isopropyl, isobutyl, neopentyl and C.sub.3-C.sub.5 alkylene;
R.sup.2, R.sup.3 and R.sup.5 are independently selected from
hydrogen, fluorine, trifluoromethyl, phenyl, C.sub.1-C.sub.10 alkyl
and C.sub.3-C.sub.5 alkylene; with the proviso that at least one of
(R.sup.1, R.sup.2) and (R.sup.3, R.sup.4) taken together is
--(CR.sup.6R.sup.7).sub.n--, where R.sup.6 and R.sup.7 are
independently selected from hydrogen, fluorine, trifluoromethyl,
C.sub.1-C.sub.5 alkyl, and C.sub.1-C.sub.5 alkyl ester, and n is 3,
4 or 5; and the reducing agent is selected from 9-BBN
(9-borabicyclo[3.3.1]nonane); diborane; boranes of the form
BR.sub.xH.sub.3-x, where x=0, 1 or 2, and R is independently
selected from phenyl and C.sub.1-C.sub.10 alkyl groups;
dihydrobenzofuran; pyrazoline; disilane; silanes of the form
SiR'.sub.yH.sub.4-y, where y=0, 1, 2 or 3, and R' is independently
selected from phenyl and C.sub.1-C.sub.10 alkyl groups; and
germanes of the form GeR''.sub.zH.sub.4-z, where z=0, 1, 2, or 3,
and R'' is independently selected from phenyl and C.sub.1-C.sub.10
alkyl groups.
[0014] Another aspect of the present invention is an article
comprising a 1,3-diimine copper complex, (I), deposited on a
substrate.
DETAILED DESCRIPTION
[0015] Applicants have discovered an atomic layer deposition (ALD)
process suitable for creation of copper films for use as seed
layers in the formation of copper interconnects in integrated
circuits, or for use in decorative or catalytic applications. This
process uses copper(I) complexes that are volatile, thermally
stable and derived from ligands that contain C, H, and N, but are
not limited to these elements. The ligands are chosen to form
copper(I) complexes that are volatile in an appropriate temperature
range but do not decompose to copper metal in this temperature
range. Rather, the complexes decompose to metal on addition of a
suitable reducing agent. The ligands are further chosen so that
they will desorb without decomposition upon exposure of the copper
complex to a reducing agent. The reduction of these copper
complexes to copper metal by readily available reducing agents has
been demonstrated to proceed cleanly at moderate temperatures.
[0016] In a process of this invention, copper is deposited on a
substrate by means of: [0017] (a) contacting a substrate with a
copper complex, (I), to form a deposit of a copper complex on the
substrate; and
[0017] ##STR00002## [0018] (b.) contacting the deposited copper
complex with a reducing agent, wherein L is selected from
C.sub.2-C.sub.15 olefins, C.sub.2-C.sub.15 alkynes, nitriles,
aromatic heterocycles, and phosphines; R.sup.1 and R.sup.4 are
independently selected from hydrogen, methyl, ethyl, propyl,
isopropyl, isobutyl, neopentyl, and C.sub.3-C.sub.5 alkylene;
R.sup.2, R.sup.3 and R.sup.5 are independently selected from
hydrogen, fluorine, trifluoromethyl, phenyl, C.sub.1-C.sub.10 alkyl
and C.sub.3-C.sub.5 alkylene, with the proviso that at least one of
(R.sup.1, R.sup.2) and (R.sup.3, R.sup.4) taken together is
--(CR.sup.6R.sup.7).sub.n--, where R.sup.6 and R.sup.7 are
independently selected from hydrogen, fluorine, trifluoromethyl,
C.sub.1-C.sub.5 alkyl, and C.sub.1-C.sub.5 alkyl ester, and n is 3,
4 or 5; and the reducing agent is selected from 9-BBN
(9-borabicyclo[3.3.1]nonane); diborane; boranes of the form
BR.sub.xH.sub.3-x, where x=0, 1 or 2, and R is independently
selected from phenyl and C.sub.1-C.sub.10 alkyl groups;
dihydrobenzofuran; pyrazoline; disilane; silanes of the form
SiR'.sub.yH.sub.4-y, where y=0, 1, 2 or 3, and R' is independently
selected from phenyl and C.sub.1-C.sub.10 alkyl groups; and
germanes of the form GeR''.sub.zH.sub.4-z, where z=0, 1, 2, or 3,
and R'' is independently selected from phenyl and C.sub.1-C.sub.10
alkyl groups.
[0019] The present deposition process improves upon the processes
described in the art by allowing the use of lower temperatures and
producing higher quality, more uniform films. The process of this
invention also provides a more direct route to a copper film,
avoiding the formation of an intermediate oxide film.
[0020] In a copper deposition process of this invention, the copper
can be deposited on the surface, or in or on porosity, of the
substrate. Suitable substrates include conducting, semiconducting
and insulating substrates, including copper, silicon wafers, wafers
used in the manufacture of ultra large scale integrated circuits,
wafers prepared with dielectric material having a lower dielectric
constant than silicon dioxide, and silicon dioxide and low k
substrates coated with a barrier layer. Barrier layers to prevent
the migration of copper include tantalum, tantalum nitride,
titanium, titanium nitride, tantalum silicon nitride, titanium
silicon nitride, tantalum carbon nitride, and niobium nitride.
[0021] The processes of the invention can be conducted in solution,
i.e., by contacting a solution of the copper complex with the
reducing agent. However, it is preferred to expose the substrate to
a vapor of the copper complex, and then remove any excess copper
complex (i.e., undeposited complex) by vacuum or purging before
exposing the deposited complex to a vapor of the reducing agent.
After reduction of the copper complex, the free form of the ligand
can be removed via vacuum, purging, heating, rinsing with a
suitable solvent, or a combination of such steps.
[0022] This process can be repeated to build up thicker layers of
copper, or to eliminate pin-holes.
[0023] The deposition of the copper complex is typically conducted
at 0 to 200.degree. C. The reduction of the copper complex is
typically carried out at similar temperatures, 0 to 200.degree. C.,
more preferably 50 to 150.degree. C.
[0024] In the process of this invention, it is initially a copper
complex that is deposited on the substrate. The formation of a
metallic copper film does not occur until the copper complex is
exposed to the reducing agent.
[0025] Aggressive reducing agents are used to reduce the copper
complex rapidly and completely. Suitable reducing agents are
volatile and do not decompose on heating. They are also of
sufficient reducing power to react rapidly on contact with the
copper complex deposited on the substrate surface. Suitable
reducing agents have been identified that have been used for
copper(I) reduction in an ALD process. One feature of these
reagents is the presence of a proton donor. The reducing agent is
desirably able to transfer at least one electron to reduce the
copper ion of the complex and at least one proton to protonate the
ligand. It is also desirable that the oxidized reducing agent and
the protonated ligand be able to be easily removed from the surface
of the newly formed copper deposit. Preferably, the protonated
ligand is removed by vacuum, by purging or by flushing the surface
with a suitable solvent.
[0026] Suitable reducing agents for the copper deposition processes
of this invention include 9-BBN, borane, diborane,
dihydrobenzofuran, pyrazoline, germanes, diethylsilane,
dimethylsilane, ethylsilane, phenylsilane, silane and disilane.
Diethylsilane and silane are preferred.
[0027] In one embodiment of a copper deposition process, the copper
complexes are admitted to a reactor chamber containing the
substrate under conditions of temperature, time and pressure to
attain a suitable fluence of complex to the surface of the
substrate. The selection of these variables (time, T, P) will
depend on individual chamber and system design, and the desired
process rate. After at least a portion of the copper complex has
been deposited on the substrate, the undeposited complex vapor is
pumped or purged from the chamber and the reducing agent is
introduced into the chamber at a pressure of approximately 50 to
760 mTorr to reduce the adsorbed copper complex. The substrate is
held at a temperature between approximately 0 to 200 .degree. C.
during reduction. With suitable combinations of copper complex and
reducing agent, this reduction is rapid and substantially complete.
Desirably, the reaction is at least 95% complete within an exposure
time of from less than a second to several minutes. It is desired
that the products from this reaction are readily removed from the
surface of the substrate under the reducing conditions.
[0028] In one embodiment of a process of this invention, the copper
complex is a copper ,3-diimine complex (I), wherein R.sup.1 and
R.sup.5 are hydrogen groups, R.sup.2 is a methyl group, R.sup.3,
R.sup.4 are taken together to form --(CH.sub.2).sub.n--, n=3,
L=vinyltrimethylsilane, and the reducing agent is
diethylsilane.
[0029] This invention also provides novel 1,3-diimine copper
complexes, (I),
##STR00003##
wherein L is selected from C.sub.2-C.sub.15 olefins,
C.sub.2-C.sub.15 alkynes, nitriles, aromatic heterocycles, and
phosphines; R.sup.1 and R.sup.4 are independently selected from
hydrogen, methyl, ethyl, propyl, isopropyl, isobutyl, neopentyl and
C.sub.3-C.sub.5 alkylene; R.sup.2, R.sup.3 and R.sup.5 are
independently selected from hydrogen, fluorine, trifluoromethyl,
phenyl, C.sub.1-C.sub.10 alkyl and C.sub.3-C.sub.5 alkylene, with
the proviso that at least one of (R.sup.1, R.sup.2) and (R.sup.3,
R.sup.4) taken together is --(CR.sup.6R.sup.7).sub.n--, where
R.sup.6 and R.sup.7 are independently selected from hydrogen,
fluorine, trifluoromethyl, C.sub.1-C.sub.5 alkyl, and
C.sub.1-C.sub.5 alkyl ester, and n is 3, 4 or 5.
[0030] In one embodiment, L is a linear, terminal olefin. For
olefins of 4-15 carbons, L can also be an internal olefin of cis-
or trans-configuration; cis-configuration is preferred. L can be a
cyclic or bicyclic olefin. L can also be substituted, for example
with fluorine or silyl groups. Suitable olefins include, but are
not limited to, vinyltrimethylsilane, allyltrimethylsilane,
1-hexene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, and
norbornene. L can also be alkyne, nitrile, or an aromatic nitrogen
heterocycle such as pyridine, pyrazine, triazine, or N-substituted
imidazole, pyrazole, or triazole. L can also be a phosphine.
[0031] The synthesis of one ligand useful for making the copper
complexes of this invention is given in Example 1 below. Thus, a
cyclic ketimine can be deprotonated by strong base, then treated
with an electrophile such as an ester or acid halide derivative to
provide the corresponding keto cyclic enamine as an intermediate.
Treatment of this intermediate with an alkylating agent such as
dimethylsulfate, followed by the addition of a primary amine
affords the desired cyclic diketimine. Alternatively, the cyclic
ketimine, after deprotonation by strong base, can be directly
coupled with an imidoyl derivative to provide the desired cyclic
diketimine. Other ligands can be prepared similarly.
[0032] In another embodiment, this invention provides an article
comprising a 1,3-diimine copper complex of structure (I), deposited
on a substrate. Suitable substrates include: copper, silicon
wafers, wafers used in the manufacture of ultra-large scale
integrated circuits, wafers prepared with dielectric material
having a lower dielectric constant than silicon dioxide, and
silicon dioxide and low k substrates coated with a barrier layer.
Barrier layers can be used to prevent the migration of copper into
the substrate. Suitable barrier layers include: tantalum, tantalum
nitride, titanium, titanium nitride, tantalum silicon nitride,
titanium silicon nitride, tantalum carbon nitride, and niobium
nitride.
EXAMPLES
[0033] Unless otherwise stated, all organic reagents are available
from Sigma-Aldrich Corporation (Milwaukee, Wis., USA).
[Cu(CH.sub.3CN).sub.4]SO.sub.3CF.sub.3 can be prepared according to
the method described in: T. Ogura, Transition Metal Chemistry, 1,
179-182 (976).
Example 1
[0034] Preparation of
[2-(4,5-Dihydro-3H-pyrrol-2-yl)-1-methyl-vinyl]-methyl-amine
[0035] To a solution of diisopropylamine (22.2 g, 219.3 mmol) in
THF (200 mL) was dropwise added n-BuLi (2.89 M, 75.9 mL, 219.3
mmol) at -78 .degree. C. under nitrogen. Once all the n-BuLi was
added, the temperature was adjusted to -5.degree. C., and the
reaction mixture was stirred for 30 min. Then a solution of
2-methyl-1-pyrroline (11.3 g, 135.7 mmol) in THF (15 mL) was added
dropwise to the reaction mixture at -5.degree. C., and then
stirred. After 30 min, ethylacetate (9.20 g, 104.4 mmol) was added
dropwise over 30 min. The reaction mixture was stirred as the
temperature was allowed to gradually rise to room temperature, and
was continuously stirred at room temperature overnight. THF solvent
was removed under reduced pressure, then 80 mL of methanol was
added dropwise to the residue. After removing all of the volatile
solvent, ether (100 mL) was added to the residue, and the mixture
was filtered. Concentration of the filtrate under reduced pressure,
followed by column chromatography, delivered 11 g of product,
.beta.-ketoenamine (1-pyrrolidin-2-ylidene-propan-2-one, 84%).
[0036] The isolated material, 1-pyrrolidin-2-ylidene-propan-2-one,
(5 g, 39.94 mmol) was reacted with dimethlysulfate (5.04 g, 39.94
mmol) by stirring at room temperature overnight. THF (50 mL) was
added to the resultant mixture, followed by the addition of
methylamine solution (25.9 mL, 2.0 M in THF). After overnight
reaction at room temperature, the solvent was removed under reduced
pressure, followed by addition of sodium methoxide (39.94 mmol)
solution (2.16 g of MeONa in 10 mL of MeOH). After stirring the
mixture at room temperature for 30 min, the reaction mixture was
concentrated under reduced pressure. Pentane (100 mL) was added to
the residue, then the insoluble material was filtered.
Concentration of the filtrate under reduced pressure, followed by
vacuum distillation (31.degree. C., 46 mTorr), afforded 4.2 g (76%
yield) of product as a liquid.
Example 2
Preparation and Reduction of
Vinyltrimethylsilane-[[2-(4,5-Dihydro-3H-pyrrol-2-yl)-1-methyl-vinyl]-met-
hylaminate]copper
[0037] Preparation: In a dry box,
Cu[(CH.sub.3CN).sub.4]SO.sub.3CF.sub.3 (0.818 g, 2.17 mmol) and
vinyltrimethylsilane (1.09 g) were mixed together in ether (15 mL),
and the mixture was stirred at room temperature for 20 min. At the
same time, the solution of diketimine,
[2-(4,5-dihydro-3H-pyrrol-2-yl)-1-methyl-vinyl]-methylamine, (0.3
g, 2.17 mmol, prepared as in Example 1) in ether (15 mL) was
treated with .sup.tBuLi (1.28 mL, 1.7 M), and the resultant
solution was stirred at room temperature for 20 min. The butyl
lithium solution was added to the copper mixture, and the resultant
mixture was stirred at room temperature for 1 h. The reaction
mixture was concentrated under vacuum, followed by the addition of
pentane (2.times.20 mL) to the residue. Filtration, followed by
concentration of the filtrate, afforded a desired product as
viscous oil (0.63 g, 92% yield).
[0038] Reduction: This material is volatile at 55.degree. C. under
500 mTorr, and was reduced to copper metal at 100.degree. C. by
exposure to diethylsilane as a reducing agent.
[0039] Reduction on a substrate: The viscous oil
(vinyltrimethylsilane-[[2-(4,5-dihydro-3H-pyrrol-2-yl)-1-methyl-vinyl]-me-
thylaminate]copper, prepared as described above) was used as a
copper precursor to create a copper film on a substrate. The
substrate consisted of a silicon dioxide wafer with 250-Angstrom
layer of tantalum on the silicon dioxide and a 100 Angstrom layer
of copper on the tantalum.
[0040] Approximately 0.030 g of copper precursor was loaded in a
dry box into a porcelain boat. The boat and wafer (.about.1
cm.sup.2) were placed in a glass tube approximately 3.5 inches
apart. The glass tube was removed from the dry box and attached to
a vacuum line. Heating coils were attached to the glass tube
surrounding both the area around the porcelain boat and the area
around the wafer chip. This configuration allows the two areas to
be maintained at different temperatures. Following evacuation of
the system, an argon gas flow was created through the tube, passing
first over the sample in the boat and then over the wafer. The
pressure inside the tube was maintained at 120-200 mTorr. The
region around the wafer was warmed to 120.degree. C. After
approximately an hour, the temperature of the region around the
sample boat was raised to 50.degree. C. These temperatures and gas
flow were maintained for approximately 2 hours. The area around the
sample boat was then cooled to room temperature. The tube was
evacuated to a pressure of .about.10 mTorr and was back-filled with
diethylsilane. The area of the tube at 110.degree. C. quickly
turned a copper color. The apparatus was cooled and returned to the
dry box. The copper color was perceptively darker. The process was
repeated to yield a wafer with a smooth copper film.
Example 3
Preparation of
Vinyltrimethylsilane[[2-(pyrrolidin-2-ylidenemethyl)-1-pyrrolinate]copper
[0041] To a solution of diisopropylamine (11.1 g, 109.7 mmol) in
THF (200 mL) was dropwise added n-BuLi (2.89 M, 37.97 mL, 109.7
mmol) at -78.degree. C. under nitrogen. Once all the n-BuLi was
added, the temperature was adjusted to -5.degree. C., and the
reaction mixture was stirred for 30 min. Then a solution of
2-methyl-1-pyrroline (5.65 g, 67.9 mmol) in THF (15 mL) was added
dropwise to the reaction mixture at -5.degree. C., and then
stirred. After 30 min, 2-methylthio-1-pyrroline (6.02 g, 52.3 mmol)
was added dropwise over 30 min at -78.degree. C. The reaction
mixture was stirred as the temperature was allowed to gradually
rise to room temperature, and was continuously stirred at room
temperature overnight. THF solvent was removed under reduced
pressure, then 50 mL of methanol was added dropwise to the residue.
After removing all of the volatile solvent, pentane (2.times.100
mL) was added to the residue, and the mixture was filtered.
Concentration of the filtrate under reduced pressure, followed by
vacuum distillation (65.degree. C. at 110 mTorr) delivered 6.2 g of
2-(pyrrolidin-2-ylidenemethyl)-1-pyrroline (79%).
[0042] In a dry box, 2-(pyrrolidin-2-ylidenemethyl)-1-pyrroline
(0.3 g, 2 mmol) was treated with t-BuLi (1.7 M, 1.17 mL, 2 mmol) in
ether (15 mL), and the mixture was stirred at room temperature for
20 min. At the same time Cu[(CH.sub.3CN).sub.4] SO.sub.3CF.sub.3
(0.75 g, 2 mmol) and vinyltrimethylsilane (1 g, 10 mmol) were mixed
together in ether (15 mL), and the resultant mixture was stirred at
room temperature for 20 min. The pyrrolinate solution was added to
the copper solution, and the resultant mixture was stirred at room
temperature for 1 h. The reaction mixture was concentrated under
reduced pressure, followed by addition of pentane (2.times.15 mL).
Filtration, followed by concentration of filtrate, afforded the
desired product,
vinyltrimethylsilane[[2-(pyrrolidin-2-ylidenemethyl)-1-pyrrolinate]copper-
, as a viscous liquid (0.59 g, 90% yield).
Example 4
Preparation of Vinyltrimethylsilane[[2-(1-pyrrolin-2-ylmethylene)
piperidinate]copper
[0043] To a solution of diisopropylamine (6.32 g, 62.52 mmol) in
THF (100 mL) was dropwise added n-BuLi (2.89 M, 21.63 mL, 62.52
mmol) at -78.degree. C. under nitrogen. Once all the n-BuLi was
added, the temperature was adjusted to -5 .degree. C., and the
reaction mixture was stirred for 30 min. Then a solution of
2-methyl-3,4,5,6-tetrahydropyridine (3.76 g, 38.70 mmol) in THF (15
mL) was added dropwise to the reaction mixture at -5.degree. C.,
and then stirred. After 30 min, 2-methylthio-1-pyrroline (3.43 g,
29.77 mmol) was added dropwise over 30 min at -78.degree. C. The
reaction mixture was stirred as the temperature was allowed to
gradually rise to room temperature, and was continuously stirred at
room temperature overnight. THF solvent was removed under reduced
pressure, then 30 mL of methanol was added dropwise to the residue.
After removing all of the volatile solvent, pentane (2.times.50 mL)
was added to the residue, and the mixture was filtered.
Concentration of the filtrate under reduced pressure, followed by
vacuum distillation (75.degree. C. at 185 mTorr) delivered 4.1 g of
2-(1-pyrrolin-2-ylmethylene)piperidine (84%).
[0044] In a dry box, 2-(1-pyrrolin-2-ylmethylene)piperidine (0.328
g, 2 mmol) was treated with t-BuLi (1.7 M, 1.17 mL, 2 mmol) in
ether (15 mL), and the mixture was stirred at room temperature for
20 min. At the same time, Cu[(CH.sub.3CN).sub.4]SO.sub.3CF.sub.3
(0.75 g, 2 mmol) and vinyltrimethylsilane (1 g, 10 mmol) were mixed
together in ether (15 mL), and the resultant mixture was stirred at
room temperature for 20 min. The piperidine solution was added to
the copper solution, and the resultant mixture was stirred at room
temperature for 1 h. The reaction mixture was concentrated under
reduced pressure, followed by addition of pentane (2.times.15 mL).
Filtration, followed by concentration of filtrate, afforded the
desired product, vinyltrimethylsilane[[2-(1-pyrrolin-2-ylmethylene)
piperidinate]copper, as a viscous liquid (0.62 g, 91% yield).
* * * * *