Coating apparatus – Gas or vapor deposition
Reexamination Certificate
1996-07-12
2001-05-01
Morris, Terrel (Department: 1763)
Coating apparatus
Gas or vapor deposition
C118S724000, C156S345420, C095S041000, C095S045000, C095S047000, C095S053000, C095S059000, C095S128000, C095S131000, C095S142000, C095S149000
Reexamination Certificate
active
06224677
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gas recovery unit in which a Chemical Vapor Deposition (“CVD”) device is provided which is equipped with a gas introduction portion having an inert gas supply path for supplying a diluting inert gas, and a cleaning gas supply path for supplying a cleaning gas, each connected therewith, and equipped with an exhaust gas discharge portion for releasing an exhaust gas. The present invention also relates to a gas recovery unit in which an etching device is provided which is equipped with a gas introduction portion having an inert gas supply path for supplying a diluting inert gas, and an etching gas supply path for supplying an etching gas, each connected therewith, and equipped with an exhaust gas discharge portion for releasing an exhaust gas.
2. Description of the Related Art
In a gas recycle unit in which a CVD device is provided, the CVD is equipped with a gas introduction part having an inert gas supply path for supplying a diluting inert gas and a cleaning gas supply path for supplying a cleaning gas, each connected with the CVD device. The CVD device is further equipped with an exhaust gas discharge portion for releasing an exhaust gas, foreign matters such as silicon dioxide (SiO
2
), polysilicon, silicon nitride, metal silicide and amorphous silicon which are produced in said CVD device. It is therefore necessary to remove these foreign matters from the inside of the CVD device because they may have an adverse influence upon products in the CVD device. Accordingly, the introduction of a cleaning gas into the CVD device has been used to convert these foreign matters to volatile substances and to remove them. Namely, if a chemical compound, for example nitrogen trifluoride (NF
3
), which can react with these foreign matters so that they are converted to gaseous components, is introduced into said CVD device, silicon dioxide (SiO
2
) will be removed from the CVD device as silicon fluoride (SiF
4
), converted therefrom by nitrogen trifluoride (NF
3
). In the event that excess cleaning gas remains in the CVD device because it has not completely reacted with the foreign matter, it may be mixed in with the exhaust gas. Especially in a case where the cleaning gas is harmful, a gas recovery unit for recovering the cleaning gas has been proposed because the cleaning gas must be made harmless.
Additionally, in an etching device for bringing an etching gas which will react with a semiconductor film or the like into contact therewith to carry out etching, it has been desirable to recover the etching gas for the same reason.
Thus, an art of liquefying and recovering a cleaning gas or an etching gas can be devised. However, it has been pointed out that it is uneconomical to dispose of this cleaning or etching gas after it is made harmless because such gases are usually expensive. It is therefore desirable to develop an art of effectively and economically utilizing these gases.
OBJECTS AND SUMMARY
It is an object of the present invention to provide a gas recycle unit having a higher recovery efficiency and a less expensive operation cost.
It is another object of the present invention to provide a gas recovery unit for liquefying and recovering a cleaning gas or an etching gas and to reuse the recovered cleaning gas or etching gas.
It is another object of the present invention to provide a device and process capable of effectively recovering a harmful gas at a lower cost.
The characteristic construction of a gas recovery unit according to the present invention for the purpose of achieving these objects can be generally described.
Such a unit can include a CVD device which is equipped with a gas introduction portion having an inert gas supply path for supplying a diluting inert gas and a cleaning gas supply path for supplying a cleaning gas, each connected with the CVD device. The CVD device is also equipped with: an exhaust gas discharge portion for releasing an exhaust gas; an exhaust gas circulation path for circulating an exhaust gas from the CVD device; a cooling portion for cooling down and liquefying the cleaning gas in the exhaust gas; a recovery portion for recovering the cleaning gas liquefied in the cooling part; a gas recycle path is also provided for supplying the cleaning gas recovered in the recovery portion to the gas introduction portion.
In an alternative embodiment, such a unit can include an etching device equipped with a gas introduction portion having an inert gas supply path for supplying a diluting inert gas and an etching gas supply path for supplying an etching gas, each connected with the etching device. The etching device is also equipped with an exhaust gas discharge portion for releasing an exhaust gas, an exhaust gas circulation path for circulating an exhaust gas from the etching device, a cooling portion for cooling down and liquefying the etching gas in the exhaust gas, and a recovery portion for recovering the etching gas liquefied in the cooling part. A gas recycle path is also provided for supplying the etching gas recovered in the recovery portion to the gas introduction portion.
The diluting inert gas may include a gas having a boiling point lower than that of the cleaning gas or, alternatively, of the etching gas. The unit further may include a supply portion for supplying in a liquid state a cooling inert gas having the same composition as the diluting inert gas; an inert gas circulation portion which is cooled down by evaporation of the cooling inert gas; and an inert gas discharge portion for discharging the cooling inert gas evaporated in the inert gas circulation part, thereby constituting the cooling part. The inert gas discharge portion may be connected to the inert gas supply path.
The cleaning gas and/or the etching gas preferably contains at least any one of nitrogen trifluoride (NF
3
), hexafluoroethane (C
2
F
6
), chlorine trifluoride (ClF
3
), carbon tetrafluoride (CF
4
), trifluoromethane (CHF
3
), sulfur hexafluoride (SF
6
), hydrogen chloride (HCl), fluorine gas (F
2
), and chlorine gas (Cl
2
).
Further preferably, the inert gas is nitrogen gas.
REFERENCES:
patent: 2947687 (1960-08-01), Lee
patent: 2953502 (1960-09-01), Binning et al.
patent: 2960462 (1960-11-01), Lee et al.
patent: 2970106 (1961-01-01), Binning et al.
patent: 3508994 (1970-04-01), Nyrop
patent: 3616607 (1971-11-01), Klass
patent: 3648845 (1972-03-01), Riley
patent: 4086310 (1978-04-01), Bottenbruch et al.
patent: 4113628 (1978-09-01), Alegranti
patent: 4132824 (1979-01-01), Kimura et al.
patent: 4155793 (1979-05-01), Salemme et al.
patent: 4156597 (1979-05-01), Browall
patent: 4192824 (1980-03-01), Robinson et al.
patent: 4378324 (1983-03-01), Makino et al.
patent: 4460526 (1984-07-01), Makino et al.
patent: 4474662 (1984-10-01), Makino et al.
patent: 4485056 (1984-11-01), Makino et al.
patent: 4512893 (1985-04-01), Makino et al.
patent: 4551197 (1985-11-01), Guilmette et al.
patent: 4553983 (1985-11-01), Baker
patent: 4602922 (1986-07-01), Cabasso et al.
patent: 4664669 (1987-05-01), Ohyabu et al.
patent: 4689267 (1987-08-01), Takamizawa et al.
patent: 4713292 (1987-12-01), Takemura et al.
patent: 4714481 (1987-12-01), Matsuura et al.
patent: 4717394 (1988-01-01), Hayes
patent: 4741829 (1988-05-01), Takemura et al.
patent: 4743435 (1988-05-01), Kitahara et al.
patent: 4756932 (1988-07-01), Puri
patent: 4784837 (1988-11-01), Kitayama et al.
patent: 4826599 (1989-05-01), Bikson et al.
patent: 4910001 (1990-03-01), Kitahara et al.
patent: 4975259 (1990-12-01), Hyakutake et al.
patent: 4996030 (1991-02-01), Kitahara et al.
patent: 5085676 (1992-02-01), Ekiner et al.
patent: 5182088 (1993-01-01), Leondaridis et al.
patent: 5240471 (1993-08-01), Barbe et al.
patent: 5281255 (1994-01-01), Toy et al.
patent: 5326723 (1994-07-01), Petro et al.
patent: 5378439 (1995-01-01), Delobel et al.
patent: 5383957 (1995-01-01), Barbe et al.
patent: 5759214 (1998-06-01), Ohmi et al.
patent: 5785741 (1998-07-01), Li et al.
patent: 0636707A2 (1995-02-01), None
patent: 0 638 923 A2 (1995-02-01), Non
Nozawa Shigeyoshi
Tomita Shinji
Burns Doane Swecker & Mathis L.L.P.
Morris Terrel
Teisan Kabushiki Kaisha
Torres Norca L.
LandOfFree
Gas recovery unit utilizing dual use of gas does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Gas recovery unit utilizing dual use of gas, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas recovery unit utilizing dual use of gas will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2566673