Chemical apparatus and process disinfecting – deodorizing – preser – Chemical reactor – Including solid – extended surface – fluid contact reaction...
Reexamination Certificate
2001-02-15
2004-05-11
Johnson, Jerry D. (Department: 1764)
Chemical apparatus and process disinfecting, deodorizing, preser
Chemical reactor
Including solid, extended surface, fluid contact reaction...
C422S214000, C422S222000, C422S240000, C422S177000, C422S180000, C423S219000, C423S248000, C423S645000, C423S580100, C252S372000, C502S439000, C502S527120
Reexamination Certificate
active
06733732
ABSTRACT:
This application is a divisional of U.S. patent application Ser. No. 09/117,350, filed Jun. 9, 1999, now abandoned; which corresponds to International Application No. PCT/JP97/00188, filed Jan. 27, 1997. The entire disclosures of the above applications are hereby incorporated by reference.
FIELD OF THE INVENTION
The present invention is primarily used in semiconductor manufacturing facilities. More specifically, the present invention is used for supplying water when silicon dioxide film is affixed by a so-called water oxidation method (or steam oxidation method) using a process chamber.
DESCRIPTION OF THE PRIOR ART
For example, for affixing a silicon oxide film by the water oxidation method in semiconductor manufacture, high-purity water is required.
Consequently, for a conventional affixing of a silicon oxide film, as shown in
FIG. 52
, a process in which hydrogen gas H
2
and oxygen gas O
2
are allowed to combust in a quartz furnace
50
has been extensively used in which water generated by the combustion of these two gases is fed into semiconductor manufacturing equipment; and the oxide film is formed on the Si wafer surface.
In
FIG. 52
, numeral
51
designates a hydrogen gas nozzle,
52
a Si chip for ignition held in a vicinity of a top side of the hydrogen gas nozzle
51
, and
53
is a heating lamp for heating the Si chip
52
. A vicinity at a tip end of the hydrogen gas nozzle
51
inside the quartz furnace attains a high temperature from about 1800° C. to 2000° C. due to flames of combustion. In addition, an amount of oxygen gas O
2
supplied to the quartz furnace
50
is set to a level exceeding one half that of the hydrogen gas H
2
in order to completely combust the hydrogen gas H
2
and to maintain safety, and flow rates of O
2
and H
2
are respectively separately set to several liters/min.
The process of
FIG. 52
achieves excellent practical effects in that water thereby generated is of a high purity and can be instantaneously generated at a rate of several liters/min.
However, in the process of
FIG. 52
, there is a problem in that if the feed rate of hydrogen gas H
2
or oxygen gas O
2
is reduced to decrease the water amount, combustion can easily be thereby stopped and it is therefore extremely difficult to apply controls for decreasing the generated water amount, and a control range of a ratio of water to oxygen (moisture content/oxygen) is narrow.
The process has a difficulty in that because raw gas is fed directly into the reactor pipe, when combustion stops an interlock mechanism becomes indispensable to prevent explosion.
In addition, there is also a problem in that when gas flow rate is reduced, flames are generated in the vicinity of the nozzle, SiO
2
composing the quartz nozzle evaporates, and these volatile materials mix in a reactor atmosphere (H
2
O+O
2
) and contaminate a gas (H
2
O+O
2
) fed to the semiconductor manufacturing equipment to such an extent that it can no longer be used for manufacturing high performance semiconductors.
In the meantime, for solving difficulties of combustion furnace type water-generating equipment as shown in
FIG. 52
, the inventors of this application previously developed a water generating process using the equipment shown in
FIG. 53
, disclosed in Japanese unexamined Patent Publication No. Hei-6-115903.
That is, this water generating process first mixes hydrogen H
2
, oxygen O
2
and inert gas Ar to form a mixture gas C, the mixture gas C is introduced into a reaction pipe
54
made of a material having a catalytic action that can radicalize hydrogen and oxygen and at the same time the reaction pipe
54
is heated to allow hydrogen and oxygen in the mixture gas C to react, thereby generating water.
The water generating method according to the Japanese Unexamined Patent Publication No. Hei 6-115903 can obtain a mixture gas containing high-purity water ranging from low concentration on a ppb order to high concentration on a percent order, and at the same time is excellent in responsiveness, in ease of maintaining control, and in achieving high effects.
However, the water generating process using the equipment shown in
FIG. 53
still has many problems that must be solved.
A first point is that because the mixture gas C of hydrogen and oxygen and argon is introduced into the reaction pipe
54
, a reactivity degrades as compared with a case in which only hydrogen and oxygen are supplied, and as a result, the reactor size is increased. In particular, there is a case in which hydrogen or inert gas is added to water to adjust an oxidation-reduction power, and N
2
O, etc. are added to water in order to improve interface characteristics of Si and SiO
2
, and in such event, an increase of the reactor size results in an increase of gas consumption rate, posing a serious problem from a standpoint of economy, etc.
It is also a problem that even if hydrogen and oxygen finish the reaction completely, the product gas is a mixture gas of moisture and argon, and it is unable to output high-purity water only or a mixture gas of water and oxygen.
A second problem is a problem of responsiveness and reactivity of water generation. Because stainless pipes are used as a material having the catalytic action and catalytic action of pipe surfaces are utilized, it is unable to achieve a large reaction gas rate per unit surface area.
As result, when a large volume of generated water, for example, a water volume of about 1 liter/min., is required, the reaction pipe
54
itself is markedly increased and, at the same time, considerable time is taken to generate water.
A third problem is safety. In order to improve safety of this water-generating equipment, the invention of Japanese Unexamined Patent Publication No. Hei 6-115903 adjusts a heating temperature of the reaction pipe
54
to be between 50° C. and 500° C., and at the same time, the whole reaction pipe
54
is uniformly heated to the same temperature.
However, because a significant portion of the reaction between hydrogen and oxygen in the reaction pipe
54
takes place at a portion close to an inlet end of the reaction pipe
54
, the temperature of the reaction pipe
54
rises more at a portion closer to the inlet end of the mixture gas due to reaction heat.
As a result, for example, if the heating temperature of the reaction pipe
54
is set to a high temperature of about 500° C., the temperature at the reaction pipe inlet end sometimes reaches nearly about 600° C., and even in a case of argon mixture gas, ignition of hydrogen gas may result when the argon mixture rate is small.
When the temperature of the reaction pipe
54
is lowered, there is a problem in that the reaction gas increases.
SUMMARY OF THE INVENTION
A primary object of this invention is to solve the problems in the conventional water generation process or water-generating equipment for semiconductor manufacturing equipment—that is: (1) in a combustion furnace system using a quartz furnace, it is difficult to adjust the flow rate in a small flow rate region of generated water, generated water is likely to be polluted, and high-purity water cannot be obtained; (2) in a water generating process for introducing argon mixture gas into a stainless steel reaction pipe heated to a high temperature, it is unable to output water or water and oxygen mixture gas; (3) a reactor size is increased and it is difficult to downsize this equipment and at the same time, responsiveness is poor; and (4) when a heating temperature of the reactor is raised to increase reactivity and responsiveness, an inlet end temperature of the reactor rises excessively, giving rise to a danger of causing an explosion, etc.—, and it is another object of this invention to provide a water generating process, a water-generating reactor, a temperature control process for the water-generating reactor, and a process for forming a platinum coating catalyst layer of the water generating reactor which can greatly reduce the size of water-generating equipment and which can safely and stably produce high purity water at a rate exceeding 1 liter/min
Hirao Keiji
Ikeda Nobukazu
Kawada Koji
Minami Yukio
Morimoto Akihiro
Fujikin Incorporated
Griffin & Szipl PC
Johnson Jerry D.
Ridley Basia
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