Valves and valve actuation – With means to increase head and seat contact pressure – Gate valve
Reexamination Certificate
2001-08-23
2002-09-24
Fox, John (Department: 3753)
Valves and valve actuation
With means to increase head and seat contact pressure
Gate valve
C092S166000
Reexamination Certificate
active
06454241
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gate valve capable of opening, closing, and sealing an opening portion of a vacuum process chamber used in for example the manufacturing process of a semiconductor device.
The present invention also relates to a cylinder apparatus suitable for driving a gate valve etc., more particularly relates to a cylinder apparatus suitable for driving a gate valve capable of opening, closing, and sealing an opening portion of a vacuum process chamber.
2. Description of the Related Art
In a dry etching step, sputtering step, epitaxial wafer forming step, etc. in the manufacturing process of a semiconductor device, use has been made for example of a vacuum process apparatus of a multi-chamber structure comprising a plurality of vacuum process chambers connected with each other as shown in FIG.
1
.
In the vacuum process apparatus
101
illustrated in
FIG. 1
, a plurality of vacuum process chambers
105
for performing various processing are connected to the outer circumference of a transport chamber
102
to and from which a wafer W is transported. Movement of the wafer W between the transport chamber
102
and each vacuum process chamber
105
is carried out through a gate G. The opening, closing, and sealing of the gate G are carried out by a not illustrated gate valve.
In the illustrated vacuum process apparatus
101
, the wafer W is transported into the transport chamber
102
by a transport device (not illustrated) through an inlet and outlet port
103
of an inlet and outlet path
104
and held by a vacuum transport robot
107
provided in the transport chamber
102
. When the wafer W is held by the vacuum transport robot
107
, the inlet and outlet port
103
is closed and the interior of the transport chamber
102
is evacuated. At this time, the gate valves are made to seal the gates G. When the evacuation of the transport chamber
102
is completed, the gate valves are driven to open the gates G. and the wafer W is transported to a predetermined vacuum process chamber
105
by the vacuum transport robot
107
. In order to perform processing such as dry etching in the vacuum process chamber, the gate valves are driven to close the gates G, and predetermined processing such as dry etching is carried out on the wafer W. When the predetermined processing of the wafer W is completed, the gate valves are driven to open the gates G, and the wafer W is taken out of the vacuum process chamber
105
again by the vacuum transport robot
107
and automatically taken to the outside of the vacuum process apparatus
101
through the inlet and outlet port
103
.
As a gate valve capable of opening, closing, and sealing the gate G in the vacuum process apparatus
101
as described above, for example a gate valve having a cross-sectional structure shown in FIG.
2
and
FIG. 3
has been known.
In
FIG. 2
, a transport chamber
202
corresponding to the transport chamber
102
of
FIG. 1
is connected with a vacuum process chamber
203
corresponding to the vacuum process chamber
105
of FIG.
1
through the gate G. The opening and closing of this gate G are carried out by a gate valve
201
. The gate valve
201
has a valve body
205
performing opening, closing, and sealing of the gate G, a valve rod
206
to one end portion of which this valve body
205
is fixed, which is held so that it can move straight, and which can be inclined about a predetermined axis
208
, a seal bellows
207
for sealing between the transport chamber
202
and the valve rod
206
, and a not illustrated driving means for moving the valve rod
206
straight and inclining it.
The gate valve
201
illustrated in
FIG. 2
is shown in a state where the gate G is opened. In order to close and then seal the gate G, as shown in
FIG. 3
, the valve rod
206
is moved straight and then moved up to a position at which the valve body
205
closes the gate G and the valve rod
206
is inclined about the axis
208
. As a result, the valve body
205
presses against an O-ring
204
provided at the outer circumference of the gate G and seals the gate G.
In the gate valve
201
having the above structure, it is required that the sealing property when sealing the gate G by the valve body
205
be good, that there be no sliding part generating particles due to friction with the valve body
205
and the valve rod
206
provided in the transport chamber
202
, that the movement of the valve body
205
by the not illustrated driving means be smooth and possible at a high speed, that the force for inclining the valve body
205
for crushing the O-ring
204
in order to secure a sufficient seal be sufficient, that the structure be simple and inexpensive, and so on.
In the gate valve
201
having the above structure, however, in order to perform the straight movement and inclination of the valve rod
206
, sufficiently obtain a force for inclining the valve body
205
, and operate the valve body
205
smoothly and at a high speed, the structure of the driving means for driving the valve rod
206
becomes complex. As a result, there are the disadvantages that the number of parts becomes large and the gate valve
201
becomes expensive.
A cylinder driven by compressed air (hereinafter referred to as an air cylinder) is usually used for driving the valve rod
206
of the gate valve
201
of the above structure. When an air cylinder is used for driving the valve rod
206
, when the valve rod
206
is inclined so as to press against the O-ring
204
, a moment will act upon the air cylinder from the valve rod
206
as a reaction force. However, usually, an air cylinder is not structured to be able to support a large moment applied to a piston rod. An air cylinder not structured to be able to support a large moment applied to a piston rod has the disadvantage that if the moment is repeatedly applied to the piston rod, wear and fatigue are apt to occur in constituent parts such as the piston, cylinder, and sealing member and there is insufficient durability with respect to moment.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a gate valve which is simplified in structure and inexpensive, is smooth and high speed in movement of the valve body, is strong in the force for inclining the valve body, and is improved in the sealing property of the opening portion.
Another object of the present invention is to provide a cylinder apparatus improving the durability with respect to the moment acting upon the piston rod.
Still another object of the present invention is to provide a cylinder apparatus suitable for driving a gate valve.
According to a first aspect of the invention, there is provided a gate valve of the following configuration. The gate valve has a valve body provided in a sealed chamber, capable of opening and closing an opening portion of the sealed chamber, and capable of sealing the opening portion by inclination with respect to the opening portion; a valve rod to one end portion of which the valve body is fixed, held so that it can move straight and incline, provided so as to project from an interior of the sealed chamber to an outside of the sealed chamber, and provided so as to hold the sealed state of the sealed chamber by a sealing means; an inclination mechanism connected to the valve rod and inclining the valve rod; and a driving means connected to the valve rod via the inclination mechanism and supplying a drive force required for the straight movement and inclination of the valve rod. The inclination mechanism has a roller rotatably provided on the other end of the valve rod; a roller receiving member formed with a first holding portion provided facing the other end portion of the valve rod, capable of holding the roller, and holding the roller when the valve rod moves straight in a direction opening and closing the opening portion, with an inclined surface continuous with the first holding portion, capable of engaging with the roller, and engaging with the roller so as to make the valve rod incline, and with a second ho
Kinno Isamu
Tamura Yuzuru
Fox John
Jacobson & Holman PLLC
NOK Corporation
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