Material or article handling – Apparatus for moving material between zones having different...
Reexamination Certificate
2002-07-30
2004-11-16
Lillis, Eileen D. (Department: 3652)
Material or article handling
Apparatus for moving material between zones having different...
Reexamination Certificate
active
06817822
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a load port for opening and closing a door of a wafer carrier, a wafer processing apparatus, and a method of replacing atmosphere.
2. Description of the Background Art
Heretofore, a wafer carrier has been used as a container for holding wafers in a manufacturing process of semiconductor devices.
FIG. 9
is a perspective view illustrating a known wafer carrier of side-door integrated type.
FIG. 10
is a perspective view showing an inside of a carrier door
20
of the wafer carrier
100
shown in FIG.
9
.
Wafer carriers as shown in
FIG. 9
include, for example, a wafer carrier shown in a catalog made by FLUOROWARE company. This type of wafer carrier is referred to as FOUP in the SEMI Standards. FOUP is the abbreviation of a “front opening unified pod.” Detailed information, such as dimensions, is described in the SEMI Standards E 52, E 1.9, or E 47.1.
In
FIGS. 9 and 10
, reference numeral
100
denotes a wafer carrier used as a container for holding wafers,
10
denotes a carrier shell,
12
denotes a robot flange,
13
denotes a manual handle, and
14
denotes a side rail. Reference numeral
20
denotes a carrier door,
21
denotes a sealing member (packing),
22
denotes a retainer for holding wafers,
23
denotes an engaging piece of a door-clamping mechanism (stopper mechanism) for engaging to the carrier shell
10
,
24
denotes a registration-pin hole, and
25
denotes a latchkey hole. Although not shown in the drawings, inside the carrier shell
10
are formed wafer teeth for seating wafers, holes corresponding to the engaging piece
23
of the door-clamping mechanism of the carrier door
20
, thick portions, and sealing portions or the like.
As
FIG. 9
shows, the wafer carrier
100
includes the carrier shell
10
and the carrier door
20
. The carrier shell
10
is a housing having an open face in one surface, and the carrier door
20
fits to the carrier shell
10
at this open face. In the state where the carrier door
20
fits to the carrier shell
10
, that is, in the state where the carrier door
20
is closed, the wafer carrier
100
is in a sealed state.
As shown in
FIG. 10
, inside the carrier door
20
, a sealing member
21
is provided on the portion contacting the carrier shell
10
. This is used for maintaining the air-tightness of the wafer carrier
100
.
Unlike an open cassette (SEMI Standards E 1.9 and others, before 8-inch wafers), the wafer carrier
100
protects wafers from foreign matter in the air and chemical contamination by holding substrates to be processed (hereafter referred to as “wafer”) in a sealed space.
On the other hand, in order to stop the above-described wafer carrier
100
at a wafer processing apparatus (semiconductor manufacturing apparatus), and to open and close the carrier door
20
to load and unload wafers, a load port having an FIMS face specified in the SEMI Standards is required. FIMS is an abbreviation of “front-opening interface mechanical standard”.
FIG. 11
is a sectional view for illustrating a conventional wafer processing apparatus comprising a load port.
As
FIG. 11
shows, the load port
300
comprises a wall surface (body surface) for separating the mini-environment
40
in the wafer processing apparatus
200
from the exterior; a kinematic pin
31
used for aligning the wafer carrier
100
on an installation table
30
; and a load port door (FIMS door)
32
fitted to the carrier door
20
, and taken in the mini-environment
40
in the wafer processing apparatus
200
together with the carrier door
20
after the opening operation of the doors. Among the wall surfaces of the wafer processing apparatus
200
, a surface contacting a sealing surface (FOUP sealing surface)
26
of the carrier shell
10
and maintaining air-tightness is called an FIMS sealing surface
27
.
The wafer processing apparatus
200
also comprises a wafer-transferring robot
41
, and an FFU (fan filter unit)
42
for cleaning the air in the mini-environment
40
.
The sealed-type wafer carriers
100
, such as FOUP, are generally formed of a high-performance plastic material. However, since plastic materials have a property to permeate moisture or the like, moisture or the like may enter inside the wafer carrier
100
. In addition, outside air may permeate into the wafer carrier
100
through the sealing material
21
due to the mechanism of molecular diffusion or the like.
Therefore, the humidity, oxygen content, or the like tend to increase with the lapse of time.
Also, when wafers whereto a photoresist is applied are stocked in a wafer carrier
100
, the organic solvent vaporized from the photoresist applied to the wafers may adhere to the internal wall of the wafer carrier
100
. In this case, even after the wafers are removed, the organic solvent adhered to the internal wall of the wafer carrier
100
may remain intact. Thereafter, by the re-vaporization of the organic solvent, the atmosphere inside the wafer carrier
100
may be contaminated by organic compounds.
As a measure against such elevations of humidity and oxygen content, and organic contamination in a wafer carrier
100
, there has been proposed a method to introduce N
2
or dry air from the bottom of the wafer carrier
100
in the state where the carrier door
20
is closed to replace the atmosphere inside the wafer carrier
100
.
However, as
FIG. 11
shows, a plurality of wafers
16
are horizontally accommodated in the wafer carrier
100
. Therefore, there has been a problem that wafers or the like accommodated in the wafer carrier
100
interfere with N
2
gas or the dry air to replace the atmosphere inside the wafer carrier
100
.
As described above, even if the airtight wafer carrier
100
is used, there has been a problem that outside air or moisture or the like permeates due to the characteristics of plastics or rubber, and humidity or oxygen content inside the wafer carrier
100
may increase. Also, by accommodating wafers
16
whereto a photoresist is applied are accommodated, the atmosphere inside the wafer carrier
100
may be contaminated by organic compounds.
Even if N
2
gas or dry air is simply introduced into the wafer carrier
100
, obstructs in the wafer carrier
100
, such as wafers
16
, make it difficult to replace the atmosphere inside the wafer carrier
100
with a clean gas in a short time.
However, the elevation of humidity or oxygen content in the wafer carrier
100
, or organic contamination of the wafer carrier
100
raises problems of the growth of native oxide films, and poor withstand voltage of the gate.
SUMMARY OF THE INVENTION
The present invention has been conceived to solve the previously-mentioned problems and aims at providing a load port, a wafer processing apparatus, and a method of replacing gas that can replace the atmosphere inside the wafer carrier efficiently in a short time.
The above objects of the present invention are attained by a following load port, by a following wafer processing apparatus and by a following method of replacing atmosphere.
According to a first aspect of the present invention, the load port for placing a wafer carrier thereon comprises a first door for opening and closing a carrier door constituting a face of the wafer carrier. An atmosphere replacing mechanism purges atmosphere inside the wafer carrier through an open face of the wafer carrier in the state where the carrier door is open.
According to a second aspect of the present invention, the wafer processing apparatus having a load port for placing a wafer carrier thereon comprises a first door for opening and closing a carrier door constituting a face of the wafer carrier. An atmosphere replacing mechanism purges the atmosphere inside the wafer carrier through an open face of the wafer carrier in the state where the carrier door is open.
According to a third aspect of the present invention, in the method of replacing atmosphere by purging the atmosphere inside a wafer carrier placed on a load port of a wafer processing apparatus, the atmosphere inside the wafer
Fox Charles A.
Lillis Eileen D.
Semiconductor Leading Edge Technologies Inc.
LandOfFree
Load port, wafer processing apparatus, and method of... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Load port, wafer processing apparatus, and method of..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Load port, wafer processing apparatus, and method of... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3350884