Coating processes – Direct application of electrical – magnetic – wave – or... – Pretreatment of coating supply or source outside of primary...
Reexamination Certificate
2001-11-27
2003-12-02
Meeks, Timothy (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Pretreatment of coating supply or source outside of primary...
C427S571000, C427S576000, C427S250000, C427S253000, C427S255390, C118S7230AN, C118S7230MP, C118S7230ME, C118S7230ER, C118S7230IR, C156S345330, C156S345340, C156S345350, C156S345370, C156S345420, C156S345460, C156S345490
Reexamination Certificate
active
06656540
ABSTRACT:
TECHNICAL FIELD
This invention relates to methods and apparatus for the formation of a thin noble metal film by a plasma-excited vapor phase growth process.
Moreover, this invention also relates to apparatus and methods for forming a metal film on a substrate surface by a vapor phase growth process.
Furthermore, this invention also relates to apparatus for the vapor phase growth of a thin copper film which are useful, for example, in the formation of wiring material films for use in semiconductor devices.
BACKGROUND ART
Conventionally, where it is desired to form a thin noble metal film by a vapor phase growth process, such a film has been formed by the utilization of a thermal reaction using a liquid organometallic complex, such as copper hexafluoroacetylacetonato-trimethylvinylsilane [hereinafter referred to as Cu(hfac)(tmvs)], as a raw material.
FIG. 22
is a schematic view of a conventional apparatus
500
for the vapor phase growth of a thin noble metal film. The method for forming a thin noble metal film
541
on a substrate
515
by using this apparatus
500
is described below. First of all, a liquid raw material
522
comprising Cu(hfac)(tmvs) is contained in a raw material vessel
521
, and a carrier gas comprising He gas is bubbled therethrough. The raw material evaporated by bubbling and H
2
for reduction reaction are passed through flow controllers
503
,
506
to control their flow rates, respectively, and fed into an inlet vessel
511
having a vaporizer
520
for vaporizing the raw material completely. Thereafter, the resulting precursor
513
is introduced into a reaction vessel
501
through a perforated plate
512
. A substrate
515
is disposed beneath perforated plate
512
and placed on a heater
516
. In this method, the growth rate and the film quality have been improved by controlling the flow rates of raw material
522
and H
2
for reduction reaction and the growth temperature.
However, the above-described prior art involves the following three problems.
First, since this method is based on the utilization of a thermal reaction induced on the substrate surface by heating substrate
515
, it has been difficult to improve the rate of film growth.
Secondly, the organometallic complex [e.g., Cu(hfac)(tmvs)] used as the raw material is expensive.
Thirdly, since hexafluoroacetylacetonato (hfac) and trimethylvinylsilane (tmvs) attached to Cu in Cu(hfac)(tmvs) remain in the thin Cu film (constituting thin film
541
) as impurities, it has been difficult to improve the film quality.
Moreover, where it is desired to form a metal film (e.g., a thin copper film) by a vapor phase growth process, it has been conventional practice to use a liquid organometallic complex (e.g., copper hexafluoroacetylacetonato-trimethylvinylsilane) as a raw material, dissolve the solid raw material in a solvent, vaporize it, and form a film on a substrate by the utilization of a thermal reaction.
However, since the prior art involves the formation of a film by the utilization of a thermal reaction, it has been difficult to improve the rate of film growth. Moreover, the metal complex used as the raw material is expensive. Furthermore, since hexafluoroacetylacetonato and trimethylvinylsilane attached to Cu remain in the thin Cu film as impurities, it has been difficult to improve the film quality.
Furthermore, a thin copper (Cu) film has conventionally been formed by physical film-forming processes such as vacuum evaporation, ion plating and sputtering, and a chemical vapor phase growth process (CVD process). Among others, the CVD process is widely employed because of its excellent surface covering properties.
According to a conventionally known method for the formation of a thin copper film by the CVD process, a liquid organocopper complex such as copper hexafluoroacetylacetonato-trimethylvinylsilane [hereinafter referred to as Cu(hfac)(tmvs)] is used as a raw material. This raw material is evaporated, carried to a desired surface of a substrate to be treated, and thermally decomposed to form a thin copper film on the substrate surface.
The above-described method for the formation of a thin copper metal is more specifically described with reference to
FIG. 23
illustrating an apparatus
600
for the vapor phase growth of a thin copper film. First of all, a substrate
603
to be treated is placed on a flat plate type heater
602
within a reaction vessel
601
. The gas within the aforesaid reaction vessel
601
is discharged through an exhaust pipe
604
until a predetermined degree of vacuum is reached. Subsequently, a carrier gas such as He is fed through a pipe
607
a
and bubbled through a raw material
605
[i.e., Cu(hfac)(tmvs)] contained in a raw material vessel
606
. The raw material gas obtained by bubbling and a reducing gas (e.g., hydrogen) are conducted through pipes
607
b
and
607
c
, respectively, and fed into a vaporizer
608
disposed in the upper part of the aforesaid reaction vessel
601
. The flow rates of the aforesaid raw material gas and hydrogen gas are controlled by flow controllers
609
and
610
installed in the respective pipes
607
b
and
607
c
. After the raw material gas is completely vaporized in the aforesaid vaporizer
608
, a mixed gas
613
composed of the raw material gas and hydrogen gas is discharged through a plurality of discharge orifices
612
of a discharge plate
611
disposed at the bottom of vaporizer
608
so as to travel toward the aforesaid substrate
603
placed on the aforesaid heater
602
. Since the aforesaid substrate
603
is heated to a predetermined temperature by the aforesaid flat plate type heater
602
, the aforesaid raw material, or Cu(hfac)(tmvs), is thermally decomposed on the surface of substrate
603
to form a thin copper film
614
thereon. During this film formation, the oxidation of copper is prevented by the reducing action of hydrogen. By controlling the flow rates of the aforesaid raw material and hydrogen and the heating temperature by heater
602
, the rate of copper film growth can be regulated and the film quality can be improved.
However, the above-described conventional method for the formation of a thin copper film involves the following three problems.
First, since the above-described method for the formation of a thin copper film is based on the thermal decomposition of vaporized Cu(hfac)(tmvs), it is difficult to improve the rate of film growth. Secondly, the organocopper complex [e.g., Cu(hfac)(tmvs)] used as the raw material is expensive and hence raises the cost of the resulting thin copper film. Thirdly, since hexafluoroacetylacetonato (hfac) and trimethylvinylsilane (tmvs) are incorporated into the thin copper film during its formation and remain therein as impurities, the film quality tends to be reduced.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide methods and apparatus for the formation of a thin noble metal film which can achieve a high rate of film growth, can use inexpensive raw materials, and do not allow any impurities to remain in the thin film.
Another object of the present invention is to provide methods and apparatus for the formation of a metal film which can achieve a high rate of film growth, can use inexpensive raw materials, and do not allow any impurities to remain in the film.
Still another object of the present invention is to provide an apparatus for the vapor phase growth of a thin copper film which uses inexpensive chlorine or hydrogen chloride as a raw material gas, can achieve a high rate of film growth, and can form a thin copper film of good quality containing little residual impurity and having a desired film thickness.
DISCLOSURE OF THE INVENTION
In order to accomplish the above objects, the present invention provides a method for the formation of a metal film which comprises the steps of feeding a raw material gas containing a halogen into an inlet vessel having a perforated plate made of metal; converting the raw material gas into a plasma t
Abe Takao
Goya Saneyuki
Nishimori Toshihiko
Sakamoto Hitoshi
Ueda Noriaki
Meeks Timothy
Mitsubishi Heavy Industries Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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