MOCVD processes using precursors based on organometalloid ligands

Chemical vapor deposition processes utilize as precursors volatile metal complexes with ligands containing metalloid elements silicon, germanium, tin or lead.

FIELD OF INVENTION 
This invention relates to chemical vapor deposition processes utilizing 
organometalloid compounds and metal complexes thereof. 
BACKGROUND OF THE INVENTION 
As the microelectronics industry moves into ultralarge scale integration 
(ULSI), enhancement in performance speeds of integrated circuits will be 
achieved by reducing the device feature size and thereby the overall die 
size. As a result, density constraints will require multilevel structures 
with vertical interconnects. It is expected that the use of metals with 
lower resistivity, such as gold, silver and especially copper, will be 
necessary because of the submicron geometries. 
Fabrication of interconnect structures includes one or more metallization 
steps. Metallization is commonly accomplished by physical vapor deposition 
(PVD) processes, including evaporating and sputtering. Chemical vapor 
deposition (CVD) processes have an advantage over these so-called "line of 
sight" processes in the fabrication of submicron vertical interconnects 
because conformal layers of metals are more easily produced. 
In CVD, a volatile precursor, usually a complex of a metal with an organic 
ligand, serves as a source of the metal. The precursor is delivered to the 
substrate in the vapor phase and decomposed on the surface to release the 
metal. The precursor must exhibit sufficient thermal stability to prevent 
premature degradation or contamination of the substrate and at the same 
time facilitate easy handling. Vapor pressure, the adsorption/desorption 
behaviour, the chemical reaction pathways, the decomposition temperature 
can directly affect the purity of the deposited metal film and the rate of 
thin-film formation. 
CVD precursors very frequently are based on complexes of metals with 
.beta.-diketonates such as 2,2,6,6-tetramethyl-3,5-heptanedione (thd) and 
acetylacetonate (acac) and fluorinated .beta.-diketonates, such as 
1,1,1,5,5,5-hexafluoro-2,4-pentanedione (hfa or hfac) and 
2,2-diethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedione (fod). Volatility of 
the non-fluorinated precursors is insufficient for many applications. The 
fluorinated analogs possess greater volatility, but also have a tendency 
to fragment, a consequence of fluorine migration/carbon-fluorine bond 
cleavage at elevated temperatures, leading to contamination of the 
substrate. Consequently, a need exists for precursors which retain 
volatility yet release the metal without degradation of the ligand and for 
ligands which are not labile or disposed toward fragmentation. 
It is therefore an object of this invention to develop metal complexes for 
CVD precursors that are highly volatile and yet stable at the sublimation 
point and also retain desirable processing features. It is a further 
object to develop ligands for use in CVD precursors which can induce high 
volatility in a metal and can release the metal without degradation of the 
ligand. It is a further object to provide new synthetic routes for the 
synthesis of these ligands from commercially available starting materials 
in good yields. 
SUMMARY OF THE INVENTION 
It has been surprisingly discovered that certain organic compounds 
containing silicon, germanium, tin or lead, when complexed with a metal, 
can induce high volatility in the metal complex. The resulting complexes 
are stable at the sublimation point and retain desirable processing 
features. The compounds have the structure of formula I: 
##STR1## 
wherein R.sup.1 is C.sub.2 or higher alkyl, substituted alkyl, haloalkyl, 
cycloalkyl, C.sub.7 or higher aryl, substituted aryl, heteroaryl, 
arylalkyl, alkoxy, acyl, alkyl carboxylate, aryl carboxylate, alkenyl, 
alkynyl, or 
E.sup.2 (R.sup.6)(R.sup.7)(R.sup.8); 
R.sup.2 is H, halogen, nitro, or haloalkyl; 
E.sup.1 and E.sup.2 are independently Si, Ge, Sn, or Pb; 
R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are independently 
chosen from alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
arylalkyl, alkoxy, alkenyl, alkynyl or R.sup.4 and R.sup.5, or R.sup.7 and 
R.sup.8 taken together form a divalent alkyl radical; 
Y and Z are independently O, S or NR.sup.9 ; and 
R.sup.9 is alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
heteroaryl, arylalkyl, alkoxy, alkenyl, or alkynyl. 
The present invention also relates to metal-ligand complexes that are 
highly volatile and yet stable at the sublimation point. The complexes 
also retain desirable processing features. The metal complexes of the 
present invention have the structure of formula II: 
EQU ML.sub.n .multidot.pD (II) 
wherein 
M is a metal chosen from the group consisting of: Li, Na, K, Rb, Cs, Mg, 
Ca, Sr, Ba, Sc, Y, La, Ce, Ti, Zr, Hf, Pr, V, Nb, Ta, Nd, Cr, Mo, W, Mn, 
Re, Sm, Fe, Ru, Eu, Os, Co, Rh, Ir, Gd, Ni, Pd, Pt, Tb, Cu, Ag, Au, Dy, 
Ho, Al, Ga, In, Tl, Er, Ge, Sn, Pb, Tm, Sb, Bi, Yb, and Lu; 
D is a neutral coordinating ligand; 
n is equal to the valence of M; 
p is zero or an integer from 1 to 6; and 
L is a compound of formula III: 
##STR2## 
wherein R.sup.1 is alkyl, substituted alkyl, haloalkyl, cycloalkyl, aryl, 
substituted aryl, heteroaryl, arylalkyl, alkoxy, acyl, alkyl carboxylate, 
aryl carboxylate, alkenyl, alkynyl, or E.sup.2 
(R.sup.6)(R.sup.7)(R.sup.8); 
R.sup.2 is H, halogen, nitro, or haloalkyl; 
E.sup.1 and E.sup.2 are independently Si, Ge, Sn, or Pb; 
R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are independently 
chosen from alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
arylalkyl, alkoxy, alkenyl, alkynyl or R.sup.4 and R.sup.5, or R.sup.7 and 
R.sup.8 taken together formn a divalent alkyl radical; Y and Z are 
independently O, S or NR.sup.9 ; and 
R.sup.9 is alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
heteroaryl, arylalkyl, alkoxy, alkenyl, or alkynyl. 
In another aspect, the present invention relates to a method of depositing 
a metal-containing layer on a substrate comprising vaporizing a 
metal-ligand complex of formula II and decomposing the metal-ligand 
complex in the presence of the substrate. 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention relates to organometalloid compounds that confer 
volatility on a metal when complexed therewith. Metalloids are defined 
herein as the elements silicon, germanium, tin and lead. Organometalloids 
are compounds containing one or more metalloid atoms bonded to a carbon 
atom. The organo-metalloid compounds of the present invention have the 
structure of formula I: 
##STR3## 
wherein R.sup.1 is C.sub.2 or higher alkyl, substituted alkyl, haloalkyl, 
cycloalkyl, C.sub.7 or higher aryl, substituted aryl, heteroaryl, 
arylalkyl, alkoxy, acyl, alkyl carboxylate, aryl carboxylate, alkenyl, 
alkynyl, or E.sup.2 (R.sup.6)(R.sup.7)(R.sup.8); 
R.sup.2 is H, halogen, nitro, or haloalkyl; 
E.sup.1 and E.sup.2 are independently Si, Ge, Sn, or Pb; 
R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are independently 
chosen from alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
arylalkyl, alkoxy, alkenyl, alkynyl or R.sup.4 and R.sup.5, or R.sup.7 and 
R.sup.8 taken together form a divalent alkyl radical; 
Y and Z are independently O, S or NR.sup.9 ; and 
R.sup.9 is alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
heteroaryl, arylalkyl, alkoxy, alkenyl, or alkynyl. 
In a preferred embodiment, I is a silyl .beta.-diketonate or a silyl 
.beta.-thioketonate and R.sup.1 is C.sub.2 or higher alkyl, C.sub.7 or 
higher aryl, or haloalkyl; R.sup.2 is H; R.sup.3, R.sup.4, and R.sup.5 are 
methyl; E.sup.1 is Si; and Y and Z are independently O or S. 
In a more preferred embodiment, R.sup.1 is ethyl, isopropyl, n-propyl, 
isobutyl, n-butyl, t-butyl, trifluoromethyl, heptafluoropropyl, 2-propenyl 
or phenyl; E.sup.1 is Si; and Y and Z are O or Y is S and Z is O. 
In an even more preferred embodiment the compound is one of those appearing 
in Table 1: 
TABLE 1 
__________________________________________________________________________ 
##STR4## 
##STR5## 
##STR6## 
##STR7## 
##STR8## 
##STR9## 
##STR10## 
##STR11## 
##STR12## 
##STR13## 
__________________________________________________________________________ 
The volatile metal complexes of the present invention are useful in 
processes which deposit a metal on substrate from a vapor phase, such as 
metal organic chemical vapor deposition (MOCVD) , molecular beam epitaxy 
(MBE) and atomic layer epitaxy (ALE). They have the structure of formula 
II: 
EQU ML.sub.n .multidot.pD (II) 
wherein 
M is a metal chosen from the group consisting of: Li, Na, K, Rb, Cs, Mg, 
Ca, Sr, Ba, Sc, Y, La, Ce, Ti, Zr, Hf, Pr, V, Nb, Ta, Nd, Cr, Mo, W, Mn, 
Re, Sm, Fe, Ru, Eu, Os, Co, Rh, Ir, Gd, Ni, Pd, Pt, Tb, Cu, Ag, Au, Dy, 
Ho, Al, Ga, In, Tl, Er, Ge, Sn, Pb, Tm, Sb, Bi, Yb, and Lu; 
D is a neutral coordinating ligand; 
n is equal to the valence of M; 
p is zero or an integer from 1 to 6; and 
L is a ligand of formula III: 
##STR14## 
wherein R.sup.1 is alkyl, substituted alkyl, haloalkyl, cycloalkyl, aryl, 
substituted aryl, heteroaryl, arylalkyl, alkoxy, acyl, alkyl carboxylate, 
aryl carboxylate, alkenyl, alkynyl, or E.sup.2 
(R.sup.6)(R.sup.7)(R.sup.8); 
R.sup.2 is H, halogen, nitro, or haloalkyl; 
E.sup.1 and E.sup.2 are independently Si, Ge, Sn, or Pb; 
R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, and R.sup.8 are independently 
chosen from alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
arylalkyl, alkoxy, alkenyl, alkynyl or R.sup.4 and R.sup.5, or R.sup.7 and 
R.sup.8 taken together form a divalent alkyl radical; 
Y and Z are independently O, S or NR.sup.9 ; and 
R.sup.9 is alkyl, substituted alkyl, cycloalkyl, aryl, substituted aryl, 
heteroaryl, arylalkyl, alkoxy, alkenyl, or alkynyl. 
Preferred metals are Cu, Co, Mn, Ag, In, Ce, Sr, Ba, Ru, or Au. More 
preferred metals are Cu and Ag. Preferred ligands are the preferred 
organometalloid compounds described above. Ligands having reduced oxygen 
content can reduce oxygen contamination of the substrate during metal 
deposition. Preferred metal complexes are listed in Table 2: 
TABLE 2 
__________________________________________________________________________ 
Cu((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.2 
Cu(CF.sub.3 COCHCOSi(CH.sub.3).sub.3).sub.2 
Cu((CH.sub.3 COCHCOSi(CH.sub.3).sub.3).sub.2 
Cu((CH.sub.3).sub.2 CHCH.sub.2 COCHCOSi(CH.sub.3).sub.3) 
.sub.2 
Cu(CH.sub.3 CH.sub.2 COCHCOSi(CH.sub.3).sub.3).sub.2 
Cu(CF.sub.3 (CF.sub.2).sub.2 COCHCOSi(CH.sub.3).sub.3).s 
ub.2 
Cu(CH.sub.3 CH.sub.2 CH.sub.2 COCHCOSi(CH.sub.3).sub.3).sub.2 
Cu(C.sub.6 H.sub.5 COCHCOSi(CH.sub.3).sub.3).sub.2 
Cu(CH.sub.3 (CH.sub.2).sub.3 COCHCOSi(CH.sub.3).sub.3).sub.2 
Cu(H.sub.2 C.dbd.(CH.sub.3)COCHCOSi(CH.sub.3).sub.3).sub 
.2 
Cu((CH.sub.3).sub.2 CHCOCHCOSi(CH.sub.3).sub.3).sub.2 
Co((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.3 
Ag((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3) 
Mn((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.3 
__________________________________________________________________________ 
The metal complexes of the present invention may contain one or more 
neutral coordinating ligands (D in formula II) in addition to the 
organometalloid ligands described above, in particular when the metal has 
a valence of one. Suitable coordinating ligands include Lewis bases such 
as vinyltrimethylsilane (VTMS), bis(trimethylsilyl) acetylene, 
1,5-cyclooctadiene (COD), 1,6-dimethyl-1,5-cyclooctadiene, alkyl 
phosphines, alkynes and mixtures thereof 
Synthetic methods for the preparation of .beta.-diketones are numerous and 
well documented. However, application of these strategies to the synthesis 
of silyl .beta.-diketonates is frequently unsuccessful, due to the 
reactivity of the product to the reagents or reaction conditions, and to 
the occurrence of side reactions via the cleavage of the carbonyl-silicon 
bond. Therefore, it is preferred that the organometalloid compounds of the 
present invention be prepared by the processes of the present invention. 
The organometalloid compounds may be prepared by a Claisen condensation 
between a lithium enolate and an acyl, thioacyl or imino compound having a 
leaving group adjacent to the unsaturated group. This reaction is 
illustrated in Scheme 1: 
SCHEME 1 
##STR15## 
In Scheme 1, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, 
R.sup.8, R.sup.9, E.sup.1, Y and Z are as defined for the compounds of 
formula I, above, R is alkyl, and Q is a leaving group. Suitable leaving 
groups for the process are halo, acyl, alkoxy, phenoxy, amido, 
dialkylamino and alkoxyamino. Preferably, R.sup.1 C(Y)Q is an acid 
chloride or an ester. 
In another embodiment, the organometalloid compounds are prepared as 
illustrated in Scheme 2. A thioketal-protected acylmetalloid is reacted 
with an alkyllithium compound, such as n-butyl lithium, and the product is 
subsequently reacted with a copper salt to form a protected lithium 
dithianylmetalloid cuprate. The cuprate is then reacted with an 
appropriate .alpha.-bromoketone or .alpha.-bromothioketone. The thioketal 
protecting group can be removed by methods described in the literature. 
Preferably the deprotection is accomplished by treatment with a suitable 
mercury reagent. An example of an effective mercury reagent is a 
combination of mercuric oxide and mercuric chloride. 
SCHEME 2 
##STR16## 
The metal complexes of the present invention may be prepared by reacting 
the organometalloid compounds synthesized as described above with a metal 
salt under protic or aprotic conditions. The ligand is dissolved in a 
suitable solvent and the anion of the ligand is formed by abstraction of a 
proton with base. The metal salt is then added, and the resulting metal 
ligand complex is isolated by removal of the solvent and crystallized. 
Under protic conditions, a protic base such as sodium hydroxide, may be 
used, with a protic solvent, such as an aqueous alcohol. Similarly under 
aprotic conditions, aprotic bases and solvents may be used. An example of 
a suitable aprotic solvent is tetrahydrofuran; an example of a suitable 
aprotic base is potassium hydride. 
In another embodiment, the metal complexes may be prepared directly as 
shown in Scheme 3. 
SCHEME 3 
##STR17## 
In Scheme 3, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7, 
R.sup.8, R.sup.9, E.sup.1, Y and Z are as defined for the compounds of 
formula I, above, and R is alkyl or phenyl. The starting lithium metalloid 
compound of formula E.sup.1 R.sup.3 R.sup.4 R.sup.5 Li is prepared 
according to the method described in the literature, (Still, W. C., J. 
Org. Chem. 41, 3063-3064 (1976)). The lithiummetalloid compound is then 
reacted with an appropriate compound, for example, a .beta.-diketone, a 
.beta.-thioketone, or a .beta.-keto-imine, to yield a ligand of formula I. 
Without isolating the product, a metal salt is added to form a complex of 
the metal with the ligand. 
Processes whereby metals are deposited from volatile precursors are 
utilized in many different microelectronics applications. Metals such as 
Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Sc, Y, La, or Ce are typically used in 
applications such as high k dielectrics, superconductors, and high 
refractive index materials, although their use is not limited to these 
applications. Metals such as Ti, Zr, Hf, Pr, V, Nb, Ta, Nd, Cr, Mo, W, Mn, 
Re, or Sm are typically used in microelectronic applications chemically 
combined with nitrogen or silicon as the nitride or silicide for use as 
barrier materials or hard coatings, although, again, their use is not 
limited to these applications. Metals such as Fe, Ru, Eu, Os, Co, Rh, Ir, 
Gd, Ni, Pd, Pt, Tb, Cu, Ag, Au, Dy, Zn, Cd, Hg, Ho, Al, Ga, In, Tl, and Er 
are typically used in electronics applications as metals, or metal alloys, 
in particular, as metal or metal alloy films for interconnects, 
electrodes, and mirrors, although, again, their use is not limited to 
these applications. Metals and metalloids such as Si, Ge, Sn, Pb, Tm, Sb, 
Bi, Yb, and Lu are typically used in microelectronic devices and as 
semiconductors, although, again, their use is not limited to these 
applications. 
The metal complexes of the present invention may be deposited on a 
substrate to form a layer of one or more metals in the form of the metal 
or of particular inorganic compounds, for example as an oxide, a 
hydroxide, a carbonate or a nitride. It will be apparent to a person 
skilled in the art that, if desired, he may use not only a particular 
compound of formula II but also mixtures of such compounds in which M, L, 
or both vary. A metal complex is advantageously decomposed in the vapor 
phase by a metal organic chemical vapor deposition (MOCVD), molecular beam 
epitaxy (MBE) or atomic layer epitaxy (ALE) process. The principle of 
these processes and suitable apparatuses for these purposes are well known 
in the art. 
Typically, an apparatus for deposition from the vapor phase is pressure 
tight and can be evacuated. The substrate which is to be coated is to be 
introduced into this apparatus. Under reduced pressure the complex of 
formula II is vaporized. If desired, inert or reactive gas may be present 
in the apparatus in addition to the complex of the present invention in 
the vapor state. 
The metal complex, in vapor form, is typically continuously or 
intermittently introduced into the apparatus via a special line. In some 
cases the metal complex may be introduced into the apparatus together with 
the substrate which is to be coated and not vaporized until it is within 
the apparatus. A carrier gas may optionally be used to aid in transporting 
the metal complex into the apparatus. The vaporization of the metal 
complex can be promoted by heating and if desired by the addition of the 
carrier gas. 
Decomposition of the substrate may be effected by known methods. In 
general, these are thermal decomposition, plasma-or radiation-induced 
decomposition and/or photolytic decomposition. 
Thermal decomposition from the vapor phase is usually performed so that the 
walls of the apparatus are kept cold and the substrate is heated to a 
temperature at which the desired layer is deposited on the substrate. The 
minimum temperature required for decomposition of the compound may be 
determined in each case by simple testing. Usually, the temperature to 
which the substrate is heated is above about 80.degree. C. 
The substrate may be heated in a conventional manner, for example, by 
resistance heating, inductive heating, or electric heating, or the 
substrates may be heated by radiation energy. Laser energy is particularly 
suitable for this. Laser heating is particularly advantageous in that 
lasers can be focused, and therefore can specifically heat limited areas 
on the substrate. 
An apparatus for thermal chemical vapor deposition is typically pressure 
tight such as are used in high vacuum techniques as this process is 
typically carried out under reduced pressure. The apparatus may comprise 
gas lines which can be heated for carrying the metal complexes or the 
inner gas, blockable gas inlets and outlets, temperature measuring means 
if decomposition is to be induced by radiation, a radiation source must 
also be present. 
In operation, the metal complex is introduced into the apparatus in the 
vapor phase. An inert or reactive carrier gas may be included. 
Decomposition of the metal complex may be brought about as discussed above. 
For example, the decomposition may be plasma induced by a D.C. plasma, 
high-frequency plasma, microwave plasma or glow discharge plasma. 
Alternately photolytic decomposition may be effected by using a laser 
operating at a suitable wavelength. 
The thickness of the layer deposited typically depends on the length of the 
deposition, on the partial pressure in the gas phase, on the flow rate of 
the gas and on the decomposition temperature. Depending on the desired 
layer thickness, a person skilled in the art can readily determine the 
time and deposition temperature required to produce a layer of a given 
thickness by simple tests. 
If the metal complex is decomposed under an atmosphere of an inert gas, for 
example, argon, metal-containing layers are typically deposited in which 
the metal is in essentially metallic form. The decomposition may also be 
carried out under a reactive gas atmosphere, including a reducing 
atmosphere, an oxidizing atmosphere, and a hydrolyzing or carbonizing 
atmosphere. A reducing atmosphere with hydrogen as the reactive gas is 
typically used for deposition of layers containing metals, for example, 
copper metal. Where the decomposition is carried out under an oxidizing 
atmosphere, for example, one containing oxygen, nitrogen dioxide or ozone, 
layers containing the metal in the form of an oxide are formed. 
Alternatively, it is also possible to operate in a hydrolyzing or 
carbonizing atmosphere, for instance, in the presence of water and/or 
carbon dioxide. The metal carbonate or hydroxide which is produced as an 
intermediate stage may be subsequently calcined to form the metal oxide. 
In addition, use of ammonia as a reactive gas yields layers containing the 
metal in the form of a nitride. 
The process according to the invention is also suitable for depositing 
layers which contain one or more metals. In this case, the deposition 
process is characterized in that for depositing layers containing more 
than one metal, one or more compounds of formula II or other formulas are 
decomposed simultaneously or successively.

EXAMPLES 
Example 1 
Preparation of (CH.sub.3).sub.3 CCOCH.sub.2 COSi(CH.sub.3).sub.3 (IV) via 
Claisen Condensation of a Lithium Enolate and an Acid Chloride. 
A two liter 3-neck flask held at 0.degree. -C. was equipped with a magnetic 
stirrer, a rubber septum and a silicon oil bubbler under a positive flow 
of nitrogen gas. The flask was charged with anhydrous diethyl ether (250 
mL) and diisopropylamine, (11.3 mL, 86.2 mmol), 2.5 M solution of n-BuLi 
in hexane (34.5 mL, 86.2 mmol) was added very slowly to the stirred 
solution. Once addition of the n-BuLi was complete the reaction 
temperature was maintained at 0.degree. C. for 1 h to ensure generation of 
lithium diisopropylamide, (LDA). The temperature was lowered to 
-85.degree. C. and acetyltrimethylsilane (10.0 g, 86.2 mmol), was then 
added slowly to the mixture. A smooth exothermic reaction ensued which 
resulted in the formation of corresponding organolithium anion, (Me.sub.3 
Si(C)(OLi)CH.sub.2). A second one liter single-neck flask held at 
-110.degree. C. equipped with a magnetic stirrer, a rubber septum and 
under a positive flow of nitrogen gas, was charged with anhydrous diethyl 
ether (250 mL) and trimethylacetylchloride, (10.6 mL, 86.2 mmol). After 10 
minutes the labile trimethylsilylorganolithium anion, (Me.sub.3 
Si(C)(OLi)CH.sub.2), was slowly transferred to the second flask via a 
cannula the reaction temperature was maintained between -110.degree. C. 
and -75.degree. C. After 1 hour, the reaction was essentially complete and 
was quenched with saturated ammonium chloride solution. Purification of 
the silyl .beta.-diketonate was effected via flash column chromatography 
using a 100:1 (hexane: diethyl ether) eluant. 
Example 2 
Preparation of IV via Claisen Condensation of a Lithium Enolate and an 
Ester. 
A two liter 3-neck flask held at 0.degree. C. equipped with a magnetic 
stirrer, a rubber septum and a silicon oil bubbler and under a positive 
flow of nitrogen gas was charged with anhydrous diethyl ether (250 mL) and 
diisopropylamine, (11.3 mL, 86.2 mmol). n-Butyllithium (34.4 mL, 86.2 
mmol, 2.5 M in hexane) was added very slowly to the stirred solution. Once 
addition of the n-BuLi was complete, the reaction temperature was 
maintained at 0.degree. C. for 1 hour to ensure generation of lithium 
diisopropylamide, (LDA). The temperature was then lowered to -85.degree. 
C. and acetyltrimethylsilane (10.0 g, 86.2 mmol) was added slowly to the 
mixture. A smooth exothermic reaction ensued which resulted in the 
formation of corresponding lithium enolate, (Me.sub.3 Si(C)(OLi)CH.sub.2). 
A second one -liter single-neck flask held at -110.degree. C. equipped 
with a magnetic stirrer, a rubber septum and under a positive flow of 
nitrogen gas, was charged with anhydrous diethyl ether (250 mL) and methyl 
pivaloate, (10.6 mL, 86.2 mmol). After 10 minutes, the reactive lithium 
enolate, (Me.sub.3 Si(C)(OLi)CH.sub.2), was slowly transferred to this 
mixture via a cannula while the reaction temperature was maintained 
between -110.degree. C. and -75.degree. C. After 2 hours, the reaction was 
essentially complete and was then quenched with saturated ammonium 
chloride solution. Purification of the silyl .beta.-diketonate was 
effected via flash column chromatography using a 100:1 (hexane:diethyl 
ether) solvent system. 
Example 3 
Preparation of IV via Pseudo Barbier Conditions. 
Trimethylsilyllithium, (18 mmol) was prepared according to the literature 
method (Still, W. C., J. Org. Chem., 41, 3063-3064 (1976)) and then 
transferred via cannula to a second reaction flask held at -78.degree. C., 
charged with anhydrous diethyl ether, (150 mL) and methyl 
4,4-dimethyl-3-oxopentanoate, (CH.sub.3).sub.3 CCOCH.sub.2 CO.sub.2 
CH.sub.3 (2.09g, 18 mmol), which resulted in the dissipation of the red 
colour. (Gasking, E. I.; Whitman, G. H. J. Chem. Soc., Perkin Trans. 1, 
1985, 409-414) After 30 minutes the reaction was quenched with saturated 
ammonium chloride, (100 mL) and copper acetate (II) monohydrate, (3.60g, 
18 mmol) was added to yield the crude silyl .beta.-diketonate copper 
complex. Subsequent purification yielded pure metal complex. 
Example 4 
Preparation of IV by the Dithiane Route. 
A 3-neck flask held at -30.degree. C. was equipped with a magnetic stirrer, 
a rubber septum and a silicon oil bubbler was under a positive flow of 
nitrogen gas. The flask was charged with anhydrous THF (30 mL) and 
2-trimethylsilane-1,3-dithiane, (3.8 mL, (20 mmol). n-Butyllithium (8.0 
mL, 20 mmol, 2.5 M in hexane) was added very slowly to the stirred 
solution. Once addition of n-BuLi was complete the reaction temperature 
was maintained at -30.degree. C. for 24 hour to ensure generation of 
2-lithio-1,3 dithiane. The anion was transferred via a cannula to a second 
flask maintained at -60.degree. C. and charged with an ethereal solution 
of CuBr.multidot.Me.sub.2 S (2.06 g, 10 mmol). After approximately one 
hour the formation of the 2-lithio-1,3-dithianylcuprate was essentially 
complete. Bromo pinacolone, (CH.sub.3).sub.3 CCOCH.sub.2 Br, dissolved in 
ether, was then added slowly to the organocuprate and was allowed to react 
for 24 hour at -30.degree. C. The reaction was quenched with saturated 
ammonium chloride solution. Vacuum distillation (125-130.degree. C., 0.5 
mm Hg) afforded the pure product. 
Deprotection of the dithiane protected silyl .beta.-diketonate was achieved 
by treatment with mercuric oxide and mercuric chloride in an aqueous 
alcoholic solution for 1.5 hours, yielding the desired the silyl 
.beta.-diketonate upon filtration and concentration. 
Example 5 
Formation of Co((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.3 under 
Protic Conditions. 
A solution of IV (0.54 g, 2.7 mmol) prepared as in Example 1 in aqueous 
ethanol (80 mL) was prepared. To the stirred solution, an aqueous 
ethanolic solution of sodium hydroxide (0.1 g, 3 mmol) was slowly added 
and allowed to react approximately 15 minutes. The slow addition of this 
solution to cobalt (II) chloride hexahydrate, (0.30 g, 1.4 mmol) dissolved 
in aqueous ethanol resulted in the formation of a deep green solution. The 
solvent was removed in vacuo to leave behind the crude cobalt (III)silyl 
.beta.-diketonate complex. Addition of pentane and water, followed by 
subsequent work-up and sublimation resulted in isolation of the 
analytically pure metal complex. 
Example 6 
Formation of Cu((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.2 under 
Aprotic Conditions. 
Under aprotic conditions, IV (0.25 g, 1.3 mmol), prepared as in Example 1, 
was dissolved in THF (100 mL). To the stirred solution, potassium hydride, 
(KH), (0.05 g, 1 mmol) was added slowly and allowed to react for 
approximately 30 minutes. The addition of copper (II) chloride dihydrate, 
(0.11 g, 6.3 mmol) portionwise resulted in the formation of a deep green 
solution. The reaction was then quenched carefully with water and 
extracted with pentane. The solvent was then removed in vacuo to leave 
behind the copper (II) silyl .beta.-diketonate complex, which on 
sublimation yielded the analytically pure metal complex. 
Example 7 
Formation of Cu((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.2 under 
Protic Conditions. 
Under protic conditions, IV (0.25 g, 1.3 mmol), prepared as in Example 1, 
was dissolved in aqueous ethanol (80 mL). To the stirred solution, an 
aqueous ethanolic solution of sodium hydroxide (0.1 g, 3 mmol) was slowly 
added and allowed to react approximately 15 minutes. Copper (II) chloride 
dihydrate, (0.11 g, 6.3 mmol) was then added which resulted in the 
formation of a deep green solution. The solvent was then removed in vacuo 
to leave behind the copper (II) silyl .beta.-diketonate complex. 
Sublimation resulted in the isolation of analytically pure metal complex. 
Example 8 
Direct Formation of Cu((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.2 
using Crude IV 
To a stirred solution of crude IV (2.73g, 13.8 mmol) dissolved in THF (100 
mL), a slurry of excess copper (II) acetate hydrate, (5.46 g, 27.4 mmol) 
in aqueous THF was added. Upon addition, a deep green solution formed. 
Extraction, washing, drying, and concentration resulted in isolation of a 
green oil. Column chromatography on silica gel using a 100:1 hexane-ether 
eluant system yielded semi-pure copper (II) silyl .beta.-diketonate 
complex. Controlled sublimation resulted in the formation of analytically 
pure metal complex. 
Example 9 
Direct Formation of Cu((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.2 
using Pure IV 
To a stirred solution of pure IV, (5.00 g, 25 mmol) dissolved in THF (100 
mL), a slurry of copper (II) acetate hydrate, (3.00 g, 15 mmol) in aqueous 
THF was added. Upon addition, a deep green solution formed. Extraction, 
washing, drying, and concentration in vacuo resulted in isolation of the 
copper (II) silyl .beta.-diketonate complex. Sublimation resulted in the 
formation of analytically pure metal complex. 
Example 10 
Preparation of Cu(I)((CH.sub.3).sub.3 
CCOCHCOSi(CH.sub.3).sub.3).multidot.COD 
Under anaerobic conditions, 1,5-cyclooctadiene (0.1 g, 1 mmol) was added 
dropwise to a suspension of copper (I) chloride in THF. The suspension was 
stirred for 10 minutes, after which a solution of the potassium salt of IV 
(prepared by the addition of potassium hydride (0.05 g, 1 mmol) over 30 
minutes to a solution of IV (0.25 g, 1.3 mmol)), was carefully added via 
syringe and allowed to react for approximately 3 hours. The resultant 
copper(I) silyl .beta.-diketonate complex was isolated by subsequent 
anhydrous work-up. 
Example 11 
Formation of Mn((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.3 via Lewis 
Base. 
A solution of IV (0.54 g, 2.7 mmol) in aqueous ethanol (80 mL) was 
prepared. To the stirred solution was slowly added an aqueous ethanolic 
solution of sodium hydroxide (0.1 g, 3 mmol). The resultant solution was 
stirred for approximately 15 minutes and then slowly added to manganese 
(II) chloride (0.176 g, 1.4 mmol) dissolved in aqueous ethanol which 
resulted in the formation of a dark green solution. The solvent was 
removed in vacuo to leave behind the crude manganese (III) silyl 
.beta.-diketonate complex. Addition of pentane and water followed by 
subsequent work-up and sublimation yielded an analytically pure metal 
complex. 
Example 12 
Preparation of Cu((CH.sub.3).sub.3 CCSCHCOSi(CH.sub.3).sub.3).sub.2 via 
Claisen Condensation of Lithium Enolate and Thioacid Chloride. 
A two liter 3-neck flask held at 0.degree. C. was equipped with a magnetic 
stirrer, a rubber septum and a silicon oil bubbler under a positive flow 
of nitrogen gas. The flask was charged with anhydrous diethyl ether (250 
mL) and diisopropylamine (11.3 mL, 86.2 mmol). n-Butyllithium (34.5 mL of 
a 2.5 M solution in hexane, 86.2 mmol) was added very slowly to the 
stirred solution. Once the addition of BuLi was complete, the reaction 
temperature was held at 0.degree. C. for 1 hour to ensure generation of 
lithium diisopropylamide, (LDA). The temperature was lowered to 
-85.degree. C. and acetyltrimethylsilane (10.0 g, 86.2 mmol) was added 
slowly to the mixture. A smooth exothermic reaction ensued which resulted 
in the formation of corresponding organolithium enolate, (Me.sub.3 
Si(C)(OLi)CH.sub.2). A second one liter single-neck flask held at 
-110.degree. C. and equipped with a magnetic stirrer, a rubber septum 
under a positive flow of nitrogen gas, was charged with anhydrous diethyl 
ether (250 mL) and trimethylthioacetylchloride, (10.6 mL, 86.2 mmol). 
After 10 minutes, the labile trimethylsilylorganolithium anion, (Me.sub.3 
Si(C)(OLi)CH.sub.2), was slowly transferred to the second flask via 
cannula while maintaining the reaction temperature between -110.degree. C. 
and -75.degree. C. After 1 hour the reaction was quenched with saturated 
ammonium chloride solution. Purification of the .beta.-thioketoacyl-silane 
can be effected by flash column chromatography using a 100:1 
(hexane:diethyl ether) eluant. The proton NMR spectrum of the product gave 
the expected results. 
Example 13 
Volatility of Metal Complexes with Silyl .beta.-diketonates and Silyl 
.beta.-thioketonates 
Thermogravimetric analysis (TGA) was performed on samples of the metal 
complexes listed in Table 3. The samples were heated at a rate of 
10.degree. C./min under an argon atmosphere. Weight loss was associated 
with transformation of the complexes into the vapor phase. The TGA curves 
showed rapid and complete volatilization of the complexes over a narrow 
temperature range, indicating the absence of decomposition under the 
conditions employed. The temperature at which 50% of the sample, by 
weight, has volatilized (T.sub.50%) is a measure of relative volatility, 
and is listed in the table for each compound. The T.sub.50% values range 
from a low of about 111.degree. C. for the fluorinated compound 
Cu(CF.sub.3 COCHCOSi(CH.sub.3).sub.3).sub.2, to a high of about 
170.degree. C. for a complex with a phenyl-substituted ligand, Cu(C.sub.6 
H.sub.5 COCHCOSi(CH.sub.3).sub.3).sub.2. 
TABLE 3 
______________________________________ 
Volatility of Metal Diketonate Complexes 
Metal Complex T.sub.50%, .degree. C. 
______________________________________ 
Cu((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.2 
158 
Co((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.3 
167 
Mn((CH.sub.3).sub.3 CCOCHCOSi(CH.sub.3).sub.3).sub.3 
119 
Cu((CH.sub.3 COCHCOSi(CH.sub.3).sub.3).sub.2 
155 
Cu(CH.sub.3 CH.sub.2 COCHCOSi(CH.sub.3).sub.3).sub.2 
150 
Cu(CH.sub.3 CH.sub.2 CH.sub.2 COCHCOSi(CH.sub.3).sub.3).sub.2 
152 
Cu(CH.sub.3 (CH.sub.2).sub.3 COCHCOSi(CH.sub.3).sub.3).sub.2 
158 
Cu((CH.sub.3).sub.2 CHCOCHCOSi(CH.sub.3).sub.3).sub.2 
137 
Cu((CH.sub.3).sub.2 CHCH.sub.2 COCHCOSi(CH.sub.3).sub.3).sub.2 
161 
Cu(CF.sub.3 COCHCOSi(CH.sub.3).sub.3).sub.2 
111 
Cu(CF.sub.3 (CF.sub.2).sub.2 COCHCOSi(CH.sub.3).sub.3).sub.2 
120 
Cu(C.sub.6 H.sub.5 COCHCOSi(CH.sub.3).sub.3).sub.2 
170 
Cu(H.sub.2 C.dbd.(CH.sub.3)COCHCOSi(CH.sub.3).sub.3).sub.2 
134, 234 
______________________________________ 
Example 14 
Chemical Vapor Deposition of Copper 
Copper films were deposited on fragments of silicon wafers, including 
wafers having surfaces composed of silicon, silicon dioxide, patterned 
silicon dioxide, and tungsten nitride, using a copper (II) silyl 
.beta.-diketonate precursor of composition Cu((CH.sub.3).sub.3 
CCOCHCOSi(CH.sub.3).sub.3).sub.2. 
A cold wall stainless steel single wafer CVD reactor was employed for the 
depositions. The wafers were loaded into the chamber through a door and 
placed on a resistively heated stainless steel pedestal bearing a quartz 
plate and heated to 300.degree. C. under a flowing hydrogen ambient 
atmosphere. The actual temperature of the wafer was measured via a 
thermocouple contacting the top side of the wafer. The system pressure was 
then reduced to the desired deposition pressure of 500 mTorr. The pressure 
was maintained throughout the time of the deposition using an automated 
throttle valve. 
A source of the precursor was maintained at 140.degree. C. The precursor 
was delivered to the reactor by means of a hydrogen carrier/reactant gas 
bubbler at a flow rate of 60 sccm at approximately 500 mTorr . After the 
deposition, the carrier gas flow was terminated, the source was closed to 
the reactor, and the chamber was evacuated to less than 20 mTorr and then 
flushed with nitrogen gas. The heater was allowed to cool under a flow of 
nitrogen. The test wafers were retrieved from the reactor through the door 
of the reactor. 
The resulting copper films were smooth and exhibited high conformality at 
thicknesses ranging from 100 .ANG. to 3000 .ANG. (10 nm to 300 nm).