Coating apparatus – Gas or vapor deposition – With treating means
Reexamination Certificate
1999-01-22
2001-05-22
Mills, Gregory (Department: 1763)
Coating apparatus
Gas or vapor deposition
With treating means
C118S719000, C118S728000, C156S345420
Reexamination Certificate
active
06234107
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an auxiliary vacuum chamber used as a buffer or a load-lock chamber, and a vacuum processing unit which uses an auxiliary vacuum chamber, for metal film forming or etching.
BACKGROUND OF THE INVENTION
During the manufacture of semiconductor devices, various processes are conducted in a vacuum, such as etching, film forming, ashing process or sputtering. Separate vacuum processing units are used for these processes.
One type of conventional vacuum processing unit is the “cluster-tool” processing unit. It comprises a plural vacuum processing chamber, a conveying chamber connected to the plural vacuum processing chamber, an auxiliary vacuum chamber connected to the conveying chamber and having a load-lock mechanism, and a passing chamber connected to the auxiliary chamber. A conveying arm is typically provided in the conveying chamber for conveying substrates to be processed.
In the above vacuum processing unit, the conveying chamber and the plural vacuum chambers are maintained at a certain vacuum. Substrates such as wafers are passed from a transfer chamber to the conveying chamber through the auxiliary vacuum chamber. They are then conveyed by the conveying arm into their designated vacuum processing chambers where they undergo various processes. After being processed, they are conveyed back into the auxiliary vacuum chamber by the conveying arm and are passed back into the transfer chamber.
The auxiliary vacuum chamber is disposed between the transfer chamber which is kept at atmospheric pressure and the conveying chamber which is kept at a vacuum. The auxiliary vacuum chamber is maintained at a vacuum when semiconductor wafers are conveyed into and out of the conveying chamber, and is returned to atmospheric pressure when semiconductor wafers are conveyed into and out of the transfer chamber.
The auxiliary vacuum chamber has means for heating or cooling semiconductor wafers in preparation for the succeeding processing step. In addition, the auxiliary vacuum chamber may conduct degassing on the semiconductor wafers by means of heating.
The above auxiliary vacuum chamber has gates between the auxiliary vacuum chamber and other chambers to enable repeating the switching between atmospheric pressure and a vacuum. This makes costs high. In addition, repeated switching between the atmospheric pressure and the vacuum takes much time as gas has to be supplied into/removed from the entire auxiliary vacuum chamber. This prevents improvement of the throughput for all of the processes.
There have been proposals for making the interior of the whole auxiliary vacuum chamber in a vacuum to avoid the necessity to switch between atmospheric pressure and a vacuum. However, such a unit would also need a hermetically closed space for heating or cooling semiconductor wafers, and so would need gates between the auxiliary vacuum chamber and the other chambers.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide an auxiliary vacuum chamber having less gates or a vacuum processing unit which uses such an auxiliary vacuum chamber.
Another object of this invention is to provide an auxiliary vacuum chamber where switching between atmospheric pressure and a vacuum takes less time or a vacuum processing unit which uses such an auxiliary vacuum chamber.
To achieve the above objects, this invention is characterized by a feature in that an auxiliary vacuum chamber comprises: a container having an opening through which an object to be processed is taken into and out of the container, a holder movably placed in the container, which can hold the object taken therein through the opening and which can form a hermetically closed space with a portion of the container when moved in the container, supplying means for supplying a gas from an outside of the container into the hermetically closed space, and exhaust means for exhausting a gas from the hermetically closed space to the outside of the container.
This invention is also characterized by another feature in that an auxiliary vacuum chamber comprises: a container having an opening for taking an object to be processed into and out of the chamber, a holder movably placed in the container, which can hold the object taken therein through the opening and which can form a hermetically closed space with a portion of the container when moved in the container, and heating means for heating the hermetically closed space.
According to these features, the auxiliary vacuum chamber need not have gate-valves for being opened and shut to the other chambers since the holder holding the object forms a hermetically closed space with a portion of the container when moved in the container, and gas is supplied in the space by the supplying means to cool the object or heating means heats the object in the space. In addition, switching between atmospheric pressure and a vacuum takes less time since the volume of the hermetically closed space is smaller than that of the entire auxiliary vacuum chamber.
A vacuum processing unit comprising; a vacuum processing chamber which can be kept in a vacuum for conducting a process on an object to be processed in the vacuum, an auxiliary vacuum chamber having a load-lock mechanism, a conveying chamber connected to the vacuum processing chamber and the auxiliary vacuum chamber in a manner to be kept in a vacuum for conveying the object, and a transfer chamber connected to the auxiliary vacuum chamber in a manner to be kept in an atmospheric pressure, wherein the auxiliary vacuum chamber comprises: a container having an opening for taking the object therethrough into and out of one of the conveying chamber and the transfer chamber, a holder movably placed in the container, for holding the object taken therein through the opening and for forming hermetically closed space with a portion of the container, a gate valve disposed in the portion of the container defining the hermetically closed space for communicating with and closing to the other of the conveying chamber and the transfer chamber, supplying means for supplying a gas from an outside of the container into the hermetically closed space, and exhaust means for exhausting a gas from the hermetically closed space to the outside of the container.
According to this feature, the load-lock mechanism having only one gate-valve is achieved, which is advantageous in costs.
REFERENCES:
patent: 5372648 (1994-12-01), Yamamoto et al.
patent: 5855681 (1999-01-01), Maydan et al.
patent: 5855726 (1999-01-01), Soraoka et al.
patent: 5882165 (1999-03-01), Maydan et al.
patent: 5932014 (1999-08-01), Hayashi et al.
patent: 6007675 (1999-12-01), Toshima
Asao Shinsuke
Ozawa Masahito
Sohma Masaki
Tanaka Keiichi
Alejandro Luz
Mills Gregory
Smith , Gambrell & Russell, LLP
Tokyo Electron Limited
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