Chemistry of inorganic compounds – Modifying or removing component of normally gaseous mixture – Organic component
Reexamination Certificate
2001-09-21
2003-10-28
Bos, Steven (Department: 1754)
Chemistry of inorganic compounds
Modifying or removing component of normally gaseous mixture
Organic component
C502S417000, C588S253000
Reexamination Certificate
active
06638489
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for cleaning a harmful gas containing as a harmful component, an organosilicon compound represented by the general formula: CH
2
CH—SiR
3
, CH
2
CH—Si(OR)
3
, CH
2
CHCH
2
—SiR
3
or CH
2
CHCH
2
—Si(OR)
3
, wherein R is a saturated hydrocarbon group or an aromatic compound group; and a cleaning agent therefor. More particularly, it is concerned with a process for cleaning, by dry cleaning process, a harmful gas containing the above-mentioned organosilicon compound which gas is exhausted from a semiconductor manufacturing process or the like; and a cleaning agent therefor.
2. Description of the Related Arts
There has been developed in recent years, a wiring material of copper films which has low electric resistance and high electro-migration resistance as a new wiring material taking the place of the wiring material of aluminum films or aluminum alloy films. Plating, sputtering, CVD (chemical vapor deposition) and the like method have been put into practical application as a method of forming copper films. With continuous progress towards three dimensional trend of a device and multi-layer trend of a wiring material, the requirement for flatness of a thin film is steadily growing. Thus, there is expected the advancement of film forming technique by CVD method which technique is capable of forming a thin film meeting the requirements of favorable step coverage and a design rule of 0.13 &mgr;m or less.
In regard to copper film formation by means of CVD method, research and investigation have been made on a method in which any of various solid CVD feed materials is sublimed by being kept at an elevated temperature, and supplied in the form of vapor to a semiconductor manufacturing apparatus. However, disadvantages of the method such as an unreasonably small amount of vapor feed and a low rate of film formation led to unsuccess in commercialization thereof. Nevertheless, development has been made in recent years on CVD feed materials in the form of liquid such as hexafluoroacetylacetone-copper vinyltrimethylsilane [(CF
3
CO)
2
CHCu.CH
2
CHSi(CH
3
)
3
] or hexafluoroacetylacetone-copper allyltrimethylsilane [(CF
3
CO)
2
CHCu.CH
2
CHCH
2
Si(CH
3
)
3
], whereby the rate of film formation has been improved to such a level as commercializability. it being so, copper film formation was commenced by the use of the above-mentioned hexafluoroacetylacetone-copper complexes.
The CVD precursors are each used in a semiconductor manufacturing process, and thereafter exhausted to the outside of the process in the form of an organosilicon compound of a structure having a vinyl group such as vinyltrimethylsilane and allyltrimethylsilane. On account of its high toxicity, the organosilicon compound needs to be cleaned prior to the exhaust thereof into the atmosphere. However, nothing has hitherto been reported concerning an excellent means for cleaning a harmful gas containing an organosilicon compound. Such being the case, consideration is given, as a process for cleaning a harmful gas containing an organosilicon compound, to a wet cleaning process comprising absorbingly decomposing the gas in a scrubber; a dry cleaning process comprising bringing the gas into contact with activated carbon or a porous adsorbent of inorganic compound base; and a combustional cleaning process comprising burning harmful components by introducing the same into the flame of a fuel such as propane. Notwithstanding, the wet cleaning process and the combustional cleaning process each involve the problem as described hereunder.
Specifically, the wet cleaning process suffers from the disadvantages in that the cleaning unit is intricate and large sized and besides, any useful absorbing liquid has not yet been found owing to an organosilicon compound being insoluble in water. The combustional cleaning process suffers from the defect in that a combustional state is obliged to be maintained even at standby time when a harmful gas is not treated, whereby energy cost is markedly increased and besides, a large amount of carbon dioxide gas is exhausted into the atmosphere.
On the other hand, in the dry cleaning process, although having the advantages of simple cleaning unit and unnecessary fuel such as propane, there has not yet been developed any means imparted with excellent cleaning capacity (cleaning capacity for an organosilicon compound per unit amount of a cleaning agent).
SUMMARY OF THE INVENTION
In such circumstances, an object of the invention is to provide a cleaning means through a dry cleaning process imparted with excellent cleaning capacity for harmful gas containing an organosilicon compound such as vinyltrimethylsilane, said compound being represented by the general formula: CH
2
CH—SiR
3
, CH
2
CH—Si(OR)
3
, CH
2
CHCH
2
—SiR
3
or CH
2
CHCH
2
—Si(OR)
3
, wherein R is a saturated hydrocarbon group or an aromatic compound group.
Another object of the invention is to provide a cleaning agent therefor.
Other objects of the invention will become obvious from the text of this specification hereinafter disclosed.
As a result of intensive research and development accumulated by the present inventors in order to solve the above-described problems involved in the prior arts, it has been found that a cleaning agent which comprises activated carbon adhesively incorporated with bromine, iodine, a metal bromide or a metal iodide exerts excellent cleaning capacity in dry system cleaning for harmful gas containing the foregoing organosilicon compound. The present invention has been accomplished by the foregoing findings and information.
That is to say, the present invention relates to a process for cleaning a harmful gas which comprises bringing the harmful gas containing as a harmful component, an organosilicon compound represented by the general formula: CH
2
CH-SiR
3
, CH
2
CH-Si(OR)
3
, CH
2
CHCH
2
—SiR
3
or CH
2
CHCH
2
—Si(OR)
3
, wherein R is a saturated hydrocarbon group or an aromatic compound group, into contact with a cleaning agent comprising activated carbon adhesively incorporated with at least one species selected from the group consisting of bromine, iodine, a metal bromide and a metal iodide.
In addition, the present invention is concerned with a cleaning agent which comprises activated carbon adhesively incorporated with at least one species selected from the group consisting of bromine, iodine, a metal bromide and a metal iodide, and which is intended for cleaning a harmful gas containing as a harmful component, an organosilicon compound represented by the general formula: CH
2
CH—SiR
3
, CH
2
CH—Si(OR)
3
, CH
2
CHCH
2
—SiR
3
or CH
2
CHCH
2
—Si(OR)
3
, wherein R is a saturated hydrocarbon group or an aromatic compound group.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The cleaning agent and cleaning process according to the present invention are each applied to the cleaning of a harmful gas which is contained in such a gas as nitrogen, argon, helium and hydrogen, and which contains, as a harmful component, an organosilicon compound represented by the general formula: CH
2
CH—SiR
3
, CH
2
CH—Si(OR)
3
, CH
2
CHCH
2
—SiR
3
or CH
2
CHCH
2
—Si(OR)
3
, wherein R is a saturated hydrocarbon group or an aromatic compound group. The cleaning agent according to the present invention which comprises activated carbon adhesively incorporated with at least one species selected from the group consisting of bromine, iodine, a metal bromide and a metal iodide. The cleaning process according to the present invention comprises bringing the above-mentioned harmful gas into contact with the cleaning agent as mentioned above.
With regard to the gas which is an object of cleaning in the present invention, examples of the organosilicon compound represented by the general formula: CH
2
CH—SiR
3
include CH
2
CH—Si(CH
3
)
3
, CH
2
CH—Si(C
2
H
5
)
3
and CH
2
CH—Si(C
6
H
5
)
3
; and examples of the organosilicon compound represented by the general formula: CH
2
CH-Si(OR)
3
include CH
2
CH—Si(OCH
3
)
3
, CH
2
CH—Si(OCH
5
)
3
Nawa Youji
Otsuka Kenji
Takamatsu Yukichi
Tonari Kazuaki
Bos Steven
Japan Pionics Co., Ltd.
Kuhar Anthony
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