Radiant energy – Photocells; circuits and apparatus – Housings
Reexamination Certificate
2000-11-02
2001-12-04
Le, Que T. (Department: 2878)
Radiant energy
Photocells; circuits and apparatus
Housings
C250S221000
Reexamination Certificate
active
06326614
ABSTRACT:
RELATED APPLICATION
This application claims priority from Provisional Patent Application No. 60/092,626, filed Jul. 3, 1998.
TECHNICAL FIELD
The present invention relates to standard mechanical interface (SMIF) system equipment and, in particular, to a SMIF box cover hold down latch and box door latch actuating mechanism that is mechanically timed to maintain synchronism of its box cover hold down latch and box door latch operating positions.
BACKGROUND OF THE INVENTION
A system designed to incorporate SMIF permits handling of semiconductor wafers inside and outside of clean room facilities by interfacing a clean semiconductor wafer cassette transport box or pod to a clean environmental housing for semiconductor processing equipment or to other clean environments. The system concept entails mating a box door on a cassette container box to a port door on an equipment enclosure and transferring the cassette into and out of the processing equipment without exposing to outside contamination the semiconductor wafers carried by the cassette.
A standard interface is required for cassette transport boxes intended to control the transport environment of cassettes containing semiconductor wafers. The standard interface addresses the proper transport box orientation for material transfer and maintains continuity between the transport box and semiconductor processing equipment environment to control particulate matter. The SMIF specifications are set out in the Semiconductor Equipment and Materials International (SEMI) standard SEMI E19.4-94 (1992, 1996).
A SMIF system includes minimum volume, sealed boxes used for storing and transporting semiconductor wafer cassettes, canopies placed over cassette ports and wafer processing areas of semiconductor processing equipment so that the environments inside the boxes and canopies in cooperation with clean air sources become miniature clean spaces, and a transfer mechanism for loading and unloading wafer cassettes from a sealed box without external environment contamination of the wafers carried by the wafer cassette.
Wafers are stored and transported in boxes, and wafers are transferred from one of the boxes to semiconductor processing equipment in the following manner. A box is placed at an interface port on the top or bottom of the canopy covering the processing equipment. The box includes a box cover and a box door designed to mate with a port door on an interface port of the processing equipment canopy. Latches release the box and port doors simultaneously, and the box and port doors are opened simultaneously so that particles present on the external door surfaces are trapped between the box and port doors. A mechanical elevator raises or lowers the box and port doors, with the cassette riding on top, into the canopy covered space. A manipulator picks up the cassette and places it on a cassette port of the processing equipment. After processing has been completed, the reverse of the above-described operation takes place.
FIG. 1
is an exploded view of a prior art box or pod
10
and port assembly
12
of semiconductor processing equipment (not shown). Box
10
is a sealable, transportable container and includes a box cover
14
having an interior region
16
. Box
10
has a box door
18
positioned at the bottom of box
10
and mounted by port assembly
12
on the horizontal surface of a canopy of a processing station (not shown) of which the semiconductor processing equipment is a part. Port assembly
12
includes a port plate
26
, a port door
28
, and an elevator assembly (not shown). The elevator assembly transports a cassette holder
30
(
FIG. 2
) containing semiconductor wafers
32
(
FIG. 2
) from interior region
16
of box cover
14
into the region beneath the canopy of the processing station.
Box
10
can be alternately pressurized or evacuated when box cover
14
and box door
18
are sealed together to isolate interior region
16
of box cover
14
from ambient conditions. Port plate
26
is connectable to a coaxial injector/extractor
34
at a gas transfer valve
36
(FIG.
2
).
FIG. 2
is a cross sectional view of box
10
mated to port assembly
12
. Box
10
is designed to sealably mate with port assembly
12
; therefore, box cover
14
has first and second box cover sealing surfaces
44
and
46
, respectively. Box door
18
has a first box door sealing surface
48
for sealably mating with first box cover sealing surface
44
. A gasket
50
positioned and compressed between surfaces
44
and
48
forms a first seal. Port plate
26
has first and second port plate sealing surfaces
60
and
62
, respectively. First port plate sealing surface
60
sealably mates with second box cover sealing surface
46
. A gasket
52
positioned and compressed between surfaces
46
and
60
forms a second seal. Port door
28
has a port door sealing surface
64
that sealably mates with second port plate sealing surface
62
. A gasket
66
positioned and compressed between surfaces
62
and
64
forms a third seal.
Box cover
14
may include a conduit
68
that defines a channel between gas transfer valve
36
and interior region
16
of box cover
14
. A filter
70
positioned at one end of the channel filters fluids such as gases passing through conduit
68
.
Port door
28
includes an actuating mechanism having two box door latch pins
72
that project from a top surface
74
of port door
28
. Pins
72
mate with a box door latch mechanism located in box door
18
to rotate a cam component of the latch mechanism between two operating positions that secure box door
18
to or release box door
18
from box cover
14
to, respectively, close or open box
10
. A box door latch mechanism to which pins
72
are matable in a SMIF box is described in U.S. Pat. No. 4,995,430.
SUMMARY OF THE INVENTION
The present invention includes a SMIF box cover hold down latch and box door latch actuating mechanism that is installed in the port door. Two box door latch actuating pins extend from the actuating mechanism to mate with corresponding holes in the cam component of the box door latch mechanism, such as the one described in U.S. Pat. No. 4,995,430.
In a preferred embodiment, the actuating mechanism comprises a central pivot shaft from which the two box door latch actuating pins extend. The central pivot shaft includes a worm gear sector having worm gear teeth with which a motor-driven worm gear shaft engages to move the central pivot shaft about a central pivot axis between first and second predetermined angular positions. Two rod members pivotally mounted to the central pivot shaft extend in opposite directions and are pivotally connected to different slider assemblies, each of which associated with a box cover hold down latch mechanism. Each slider assembly comprises a truck that is slidably mounted on a rail functioning as a linear guide bearing and has a push pin extending outwardly to contact a corresponding box cover hold down latch mechanism. The rod members respond to pivotal movement of the central pivot shaft between the first and second angular positions by retracting to remove the push pins from and extending to force the push pins against the box cover hold down latches. The central pivot shaft and rod members form, therefore, a slider crank mechanism in which for each rod member one end pivots and the other end linearly translates in response to angular displacement of the central pivot shaft.
In operation, the actuating mechanism moves the central pivot shaft to one or the other of the first and second angular positions. Movement to the first angular position imparts linear movement of the trucks attached to first and second rod members and causes the push pins to retract from their corresponding box cover hold down latches to secure the box cover to the port plate and imparts angular movement to the two actuating pins and causes them to operate the box door latch mechanism to release the box door from the box cover. Movement to the second angular position imparts linear movement to the trucks attached to first and second rod membe
Bacchi Paul
Filipski Paul S.
Le Que T.
Newport Corporation
Stoel Rives LLP
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