Photocopying – Projection printing and copying cameras
Reexamination Certificate
1999-07-06
2004-03-16
Braun, Fred L. (Department: 2852)
Photocopying
Projection printing and copying cameras
C355S053000, C414S937000
Reexamination Certificate
active
06707528
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to exposure apparatus used, for example, in fabrication process of semiconductor devices.
2. Related Background Art
The exposure apparatus used in the photolithography step for fabricating semiconductor devices is provided with a wafer loader system for performing loading and unloading of wafers. Further, the exposure apparatus is also provided with a reticle loader system for selecting a desired reticle out of a lot of reticles and setting it at an exposure position.
FIG. 11
is a plan view to show an exposure apparatus provided with a conventional wafer loader system. In this
FIG. 11
, an air-conditioning device
2
is set in a chamber
1
substantially isolated from the external atmosphere. Clean air blows from the air-conditioning device
2
through a vent pipe
3
and a HEPA filter (High Efficiency Particulate Air filter)
4
into the chamber
1
in the form of side flow, and the air having circulated in the chamber
1
then returns to the air-conditioning device
2
through a return (exhaust port)
5
and a vent pipe
6
.
A vibration-proof table
8
is set on a floor
7
of the chamber
1
. A wafer stage
10
for a wafer
11
A of exposure object to be mounted thereon is set on this vibration-proof table
8
. The wafer stage
10
consists mainly of a Y stage
9
Y moving in the Y direction, an X stage
9
X moving in the X direction, and a wafer holder
9
T for holding the wafer. The wafer loader system
12
is placed beside the wafer stage
10
and on the vibration-proof table
8
. The wafer loader system
12
sets (or loads) the wafer
11
A on the wafer stage
10
in such a manner that a cut portion (orientation flat portion or notch portion) formed in a part of the circumference of wafer
11
A is located in a predetermined positional relation relative to the wafer stage
10
.
The wafer loader system
12
is constructed in such a basic arrangement that a vertical slider body
18
extending in the Y direction is fixed on a horizontal slider body
13
extending in the X direction. Two setting tables
21
A and
21
B are provided on a side portion of the horizontal slider body
13
. Columns of storage shelves
22
A and
22
B for process wafers are mounted on the setting tables
21
A and
21
B, respectively. Wafers before exposure or wafers after exposure are stored in the columns of storage shelves
22
A and
22
B.
Mounted on the horizontal slider body
13
are a random access member (a wafer suction arm freely movable back and forth)
14
A for taking a wafer out of the storage shelf column
22
A, a random access member (a wafer suction arm freely movable back and forth)
14
B for taking a wafer out of the storage shelf column
22
B, a wafer hand-over member
15
, and a positioning table
16
, and a turn table
17
is provided on the positioning table
16
. Further, a carry arm
20
is set on the horizontal slider body
13
so as to be movable in the X direction. Two carry arms
19
A and
19
B are provided on the vertical slider body
18
so as to be movable in the Y direction.
A wafer taken out by the random access member
14
A or
14
B is carried onto the turn table
17
by the carry arm
20
.
FIG. 12
shows the structure of the wafer loader system
12
in FIG.
11
. As shown in this
FIG. 12
, a position correcting device
25
is placed above the positioning table
16
. (including the turn table
17
). Pins (not shown) are projected from the position correcting device
25
so that they come into contact with the outer periphery of a wafer rotating on the turn table
17
. A center position of wafer and a position of the cut portion are detected based on the contact state of the pins, and, based on this detection result, the center of wafer and the position of the cut portion are set each at a predetermined position. After that, the wafer on the turn table is carried to the wafer stage by the carry arm
19
A.
Further, in
FIG. 12
, the section A shows a state wherein an in-line hand-over unit for handing over a wafer to or from a coater or a developer is provided at one end of the horizontal slider body
13
. The in-line hand-over unit herein means a carrying apparatus for carrying a wafer from a coater for or applying a photoresist to the wafer, etc. to the exposure apparatus, or a carrying apparatus for carrying a wafer after exposure from the exposure apparatus to a developing apparatus (developer) etc. The section B shows a state wherein a random access member
14
C and a setting table
21
C having a column of wafer storage shelves are added to the wafer loader system
12
. The section C shows a state wherein an in-line hand-over unit is provided at the other end of the horizontal slider body
13
.
Returning to
FIG. 11
, a first in-line hand-over unit
23
is composed of an arm
23
a
and a slide shaft
23
b
, and a second in-line hand-over unit
24
is composed of an arm
24
a
, a slide shaft
24
b
, and a rotary member
24
c
. After the arm
23
a
of the in-line hand-over unit
23
receives a wafer
11
B from a coater or a developer (not shown), the wafer
11
B is handed over to the carry arm
20
at position P
1
. Similarly, after the arm
24
a
of the in-line hand-over unit
24
receives a wafer
11
C from a coater or a developer (not shown), the wafer
11
C is handed over to the carry arm
20
via position P
2
and position P
3
. Or, conversely, a wafer is handed over from the in-line hand-over unit
23
or
24
to the coater or developer (not shown).
In the above wafer loader system
12
, the carry arm
20
, carry arm
19
A, carry arm
19
B, arm
23
a
, arm
24
a
, random access members
14
A,
14
B, positioning table
16
, and turn table
17
each were made of alumina ceramics, (containing 95 or more % of Al
2
O
3
), and plastic storage shelves (which can store twenty five wafers) mainly used in actual processes have been used as a substitute for the wafer storage shelves
22
A and
22
B.
In addition to the wafer loader system
12
, a reticle loader system (not shown) was also set on the vibration-proof table
8
. The reticle loader system is arranged to take a desired reticle out of a reticle case and to set it at the exposure position.
In the conventional technology as described above, because the wafer loader system
12
was set together with the wafer stage
10
on the vibration-proof table
8
, vibration occurring upon carrying the wafer by the wafer loader system
12
was transferred to the wafer stage
10
, which could degrade the positioning accuracy of wafer stage
10
.
Since the wafer loader system or the reticle carrying system and the wafer stage
10
are set in the same chamber
1
actuation of the carrying mechanism can allow allowed dust to be mixed about the wafer stage
10
and can change the ambient temperature thereof.
Further, because the air conditioning of the whole inside of the chamber
1
was effected by one air-conditioning device
2
and a set of HEPA filter
4
and return
5
, there were cases that necessary air-conditioning performance was not achieved at each of the exposure portion of the horizontal slider body
13
of the wafer loader system
12
, and the reticle loader system, etc., or that the air conditioning exceeded specifications.
With respect to this, for example, if the wafer loader system
12
was located on the windward side of the exposure system, there were cases that particles caused by the wafer loader system
12
, or a temperature change in this system negatively affected the exposure system on the leeward side.
Further, as shown in
FIG. 11
, when a wafer was handed over to or from the coater or developer, it was necessary to install the in-line hand-over units
23
and
24
etc. for exclusive use, which complicated the whole structure and which caused dust production because of an increase in the number of wafer hand-overs.
Also, high-accuracy positioning was difficult, because, in loading a wafer on the wafer stage
10
, the wafer positioning was carried out by a method of bringing the pins actually in contact with the wafer on
Aoyama Masaaki
Fujita Hiroyasu
Braun Fred L.
Miles & Stockbridge P.C.
Nikon Corporation
LandOfFree
Exposure apparatus having independent chambers and methods... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Exposure apparatus having independent chambers and methods..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Exposure apparatus having independent chambers and methods... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3259357