Pipes and tubular conduits – With closures and plugs
Reexamination Certificate
2000-06-14
2001-04-03
Hook, James (Department: 3752)
Pipes and tubular conduits
With closures and plugs
C138S094000, C015S314000, C220S212500
Reexamination Certificate
active
06209585
ABSTRACT:
FIELD OF THE INVENTION
The present invention generally relates to a cover for a conduit and more particularly, relates to a cover equipped with a pivotable handle for covering a conduit of a central vacuum system in a semiconductor fabrication facility.
BACKGROUND OF THE INVENTION
In the recent development of semiconductor fabrication technology, the continuous miniaturization in device fabricated demands more stringent requirements in the fabrication environment and contamination control. When the feature size was in the 2 &mgr;m range, a cleanliness class of 100-1000 (which means the number of particles at sizes larger than 0.5 &mgr;m per cubic foot) was sufficient. However, when the feature size is reduced to 0.25 &mgr;m, a cleanliness class of 0.1 is required. It has been recognized that an inert minienvironment may be the only solution to future fabrication technologies when the device size is reduced further. In order to eliminate micro-contamination and to reduce native oxide growth on silicon surfaces, the wafer processing and the loading/unloading procedures of a process tool must be enclosed in an extremely high cleanliness minienvironment that is constantly flush with ultrapure nitrogen that contains no oxygen and moisture.
Different approaches in modern clean room design have been pursued in recent years with the advent of the ULSI technology. One is the utilization of a tunnel concept in which a corridor separates the process area from the service area in order to achieve a higher level of air cleanliness. Under the concept, the majority of equipment maintenance functions are conducted in low-classified service areas, while the wafers are handled and processed in more costly high-classified process tunnels. For instance, in a process for 16M and 64M DRAM products, the requirement of contamination control in a process environment is so stringent that the control of the enclosure of the process environment for each process tool must be considered. This stringent requirement creates a new minienvironment concept which is shown in FIG.
1
. Within the enclosure of the minienvironment of a process tool
10
, an extremely high cleanliness class of 0.1 (which means the number of particles at sizes larger than 0.1 &mgr;m per cubic foot) is maintained, in contrast to a cleanliness class of 1000 for the overall production clean room area
12
. In order to maintain the high cleanliness class inside the process tool
10
, the loading and unloading sections
14
of the process tool must be handled automatically by an input/output device such as a SMIF (standard mechanical interfaces) apparatus. A cassette or wafer can be transported into the process tool
10
by SMIF pod
18
situated on top of the SMIF apparatus
20
.
In a conventional SMIF apparatus
20
such as that shown in
FIG. 1
, the apparatus
20
consists of a robotic arm which is normally configured for gripping the top of a cassette
30
from a platform on which the cassette
30
is placed (inside a pod). The robotic arm, sometimes replaced by a gripper assembly, is capable of transporting the cassette
20
into the process tool and place it onto a platform
16
vertically such that the cassette
30
is oriented horizontally. At the beginning of the process, an operator positions a SMIF pod
18
on top of a platform/elevator
22
which contains a cassette
40
holding, for instance, 24 wafers in an upright position. The elevator then descends into the SMIF apparatus
20
for the robotic arm to transport cassette
30
into the process tool. The SMIF system
20
is therefore capable of automatically utilizing clean isolation technology to maintain a high class clean room effectiveness near wafers and processing equipment. The operation of the robotic arm or the gripper is controlled by an ancillary computer (not shown) or by the process tool
10
. The cassette
30
carries wafers or other substrates that are being processed.
Also provided in the clean room is a central vacuum system (not shown) equipped with vacuum outlet
40
as shown in FIG.
1
. The vacuum outlet
40
is constructed by a vacuum conduit
42
and a cover assembly
44
. The central vacuum system is provided with vacuum outlet
40
throughout a clean room, and is normally installed in the clean room floor such that a top surface of the cover assembly
44
is flush with the top surface
32
of the clean room floor. The purpose of the central vacuum system is to provide ready access to a factory vacuum source for cleaning of processed tools or process machines.
The cover assembly
44
for the central vacuum outlet
40
is further shown in
FIGS. 1B-1D
.
FIG. 1B
is a perspective view of a cover assembly
44
positioned on top and spaced apart from the vacuum conduit
42
. The cover assembly
44
is normally provided with a recess
34
in a top surface
36
of the cover assembly
44
. The recess
34
is further provided with a pin
38
for grasp by a pair of pincers during a preventive maintenance procedure. The cover assembly
44
is constructed by an upper portion
46
and a lower portion
48
that are both formed in an annular shape. The outside diameter of the lower portion
48
is smaller than the inside diameter of the conduit
42
such that a snug fit can be achieved for a vacuum-tight seal.
FIG. 1C
illustrates a plane view of the cover assembly
44
, while
FIG. 1D
illustrates a cross-sectional view of the cover assembly
44
.
The cover assembly
44
illustrated in
FIGS. 1A-1D
serves the purpose of sealing a vacuum outlet
40
. However, whenever an operator needs to use the vacuum by attaching a hose connector to the conduit
42
, a pair of pincers or Allen wrench must be used to pick up the cover assembly
44
by the pin
38
. This process must be repeated several times a day whenever the process chamber, or the process machine needs to be cleaned. To facilitate the removal of the cover assembly
44
, other attempts have been made such as tying a cable tie to the pin
38
so that the cover assembly
44
can be picked up by pulling on the cable tie. However, the cable tie arrangement can produce particle contaminations for the clean room environment. It is therefore highly undesirable to introduce a foreign object for picking the cover assembly
44
, i.e. either by a tool or by a cable tie that is tied to the cover assembly
44
.
SUMMARY OF THE INVENTION
The present invention discloses a cover assembly that is equipped with a pivotable handle for a conduit opening which can be easily operated in a clean room floor of a semiconductor fabrication facility.
In a preferred embodiment, a cover assembly that is equipped with a pivotable handle for a conduit opening is provided which includes a cover body of generally annular shape that has an upper portion and a lower portion integrally formed together, the upper portion has an outside diameter not smaller than an outside diameter of the conduit opening, the lower portion has an outside diameter smaller than an inside diameter of the conduit opening for sealing the conduit opening when the lower portion of the cover body is inserted into the conduit opening such that a bottom surface of the upper portion sealingly engages an end surface of the conduit opening, the upper portion further includes a recess in a top surface for concealing the pivotable handle therein; and a pivotable handle of generally an elongated rectangular shape that has an elongated slot opening in a longitudinal direction therethrough and a finger grip at one end of the handle, the elongated slot opening slidingly engages a pin mounted in a horizontal position in the recess such that the pivotable handle rests horizontally in the recess when not used and stands vertically in the recess when pulled up by the finger grip by a sliding engagement between the elongated slot opening and the horizontally mounted pin.
In the cover assembly that is equipped with a pivotable handle for a conduit opening, an outside peripheral surface of the lower portion of the cover body frictionally engages an inside peripheral surface of the conduit
Hook James
Taiwan Semiconductor Manufacturing Co. Ltd.
Tung & Associates
LandOfFree
Cover with pivotable handle for a vacuum conduit does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cover with pivotable handle for a vacuum conduit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cover with pivotable handle for a vacuum conduit will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2521606