Measuring and testing – Testing of apparatus
Reexamination Certificate
1999-06-01
2002-06-18
Williams, Hezron (Department: 2856)
Measuring and testing
Testing of apparatus
C414S222010, C414S222020, C414S222070
Reexamination Certificate
active
06405610
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wafer inspection apparatus and, more particularly, to various types of structures for realizing a reduction in convey time of a wafer as an inspection target, an improvement in operability, or the like.
2. Related Background Art
A conventional wafer inspection apparatus has at least a microscopic observation system in order to observe a wafer serving as an inspection target by using a microscope. In order to realize automatic microscopic observation of the wafer, the conventional wafer inspection apparatus generally has a function of temporarily storing the wafer and a structure for conveying the wafer to a desired position to microscopically observe it.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a wafer inspection apparatus having various types of structures for realizing a reduction in convey time of a wafer as an inspection target, an improvement in operability, or the like. A wafer inspection apparatus according to the present invention has at least a wafer convey system and a microscopic observation system to realize efficient wafer observation.
More specifically, in the wafer inspection apparatus according to the present invention, as shown in
FIGS. 1
to
3
, at least a first convey system
4
and a second convey system
5
prepared as the wafer convey system, and a macro observation system
6
and a microscopic observation system
7
prepared as the observation system are mounted on a main flat surface
1
a
of an operation board
1
on which an input unit
100
, e.g., a pointing device, is provided. This wafer inspection apparatus is also provided with a monitor
8
for displaying a desired image, e.g., control information, character information, or the like, regarding operation for wafer inspection.
Most of these systems mounted on the operation board
1
are covered with a cover
9
except at least the observation systems
6
and
7
, to ensure the safety of the person, the operator, or the like who is in charge of wafer inspection. The portions that handle the wafer are exposed from a major surface
90
of the cover
9
through a plurality of openings
92
and
94
(see FIG.
2
). Accordingly, the wafer serving as the inspection target is conveyed through the space above the main surface
1
a
of the operation board
1
. Thus, in this specification, the main surface
1
a
of the operation board
1
corresponds to a wafer convey reference surface of the wafer inspection apparatus according to the present invention. Each lifting unit
2
has a driving system for moving its setting surface
2
a
in a direction perpendicular to the main surface
1
a
as the wafer convey reference surface.
The wafer inspection apparatus according to the present invention has the lifting units
2
on a power supply unit
11
. Each lifting unit
2
has the setting surface
2
a
on which a cassette member
3
for storing wafers can be set, and positions the cassette member
3
at a predetermined position while holding it.
In particular, when the cassette member
3
is set a on the setting surface
2
a
of the lifting unit
2
, the setting surface
2
a
is positioned, with reference to the main surface
1
a
of the operation board
1
of the wafer inspection apparatus, at a position lower than the observation reference surface on which the conveyed wafer is set. In this manner, since the cassette member
3
storing the wafers can be set on the lifting unit
2
easily, a physical burden to the operator or the like who handles the cassette member
3
can be reduced, thereby improving the operability of the wafer inspection apparatus. In other words, as shown in
FIG. 1
, the position Q
2
corresponding to a mount surface of the operation board
1
on which the cassette member
3
is set is lower than the position Q
1
corresponding to the main surface
1
a
of the operation board
1
. Therefore, the mount surface (position Q
2
) on which the lifting unit
2
is set is positioned at a lower position than the main surface
1
a
(position Q
1
) in the direction perpendicular to the main surface
1
a
. The lifting unit
2
can position the setting surface
2
a
at a lower position than the main surface
1
a
of the operation board
1
. In this specification, the observation reference surface means a plane including a main surface
60
a
(see
FIG. 17
) of a wafer stage
60
, that holds the wafer, of the macro observation system
6
for allowing visual inspection by the observer, or a main surface
741
(see
FIG. 18
) of a holder
740
, that holds the wafer, and in parallel with respect to the main surface
1
a
of the operation board
1
.
A plurality of types of cassette members
3
having different sizes (e.g., a 4-inch wafer cassette member and a 8-inch wafer cassette member) can be set on the setting surface
2
a
of the lifting unit
2
, respectively. The lifting unit
2
has a first detector
20
a
and a second detector
20
b
. The first detector
20
a
is provided in an area of the setting surface
2
a
where a first area AR
1
which is in contact with a small cassette member and a second area AR
2
which is in contact with a large cassette member overlap. The second detector
20
b
is provided in a portion of the second area AR
2
which does not overlap the first area AR
1
. The first detector
20
a
outputs a first detection signal when a cassette member of any size is set on the setting surface
2
a
of the lifting unit
2
. The second detector
20
b
outputs a second detection signal when a large cassette member is set on the setting surface
2
a
of the lifting unit
2
.
With this arrangement, a main controller
10
can determine that a small cassette member is set on the lifting unit
2
when it receives the first detection signal from the first detector
20
a
and does not receive the second detection signal from the second detector
20
b
, and can determine that a large cassette member is set on the lifting unit
2
when it receives the first and second detection signals from both of the first and second detectors
20
a
and
20
b
. The main controller
10
controls the input unit
100
, e.g., a pointing device
1
b
or a keyboard
1
c
, the lifting unit
2
including the first and second detectors
20
a
and
20
b
and the driving system for moving the setting surface
2
a
, the microscopic observation system
7
including the X-Y stage
71
(see FIG.
18
), the macro observation system
6
including a driving system (see FIG.
17
), the first convey system
4
including a driving system (see FIGS.,
10
,
15
and
16
), the second convey system
5
including the driving system (see FIG.
22
), and the monitor
8
in a centralized manner, as shown in, e.g., FIG.
3
.
As described above, this wafer convey system includes the cassette member
3
set on the lifting unit
2
, the first convey system
4
for conveying wafers between the cassette member
3
and a predetermined area located between the cassette member
3
and the observation system, and the second convey system
5
for conveying wafers between the predetermined area and the observation system. Further, the first convey system
4
extracts and stores the wafers from and in the cassette member
3
. In particular, each of the convey systems
4
and
5
has a mechanism for conveying the wafers while correcting a difference between the setting surface
2
a
and the observation reference surface
741
(or
60
a
) in a direction perpendicular (in the direction of height) to the main surface
1
a
(the wafer convey reference surface) of the operation board
1
.
The first convey system
4
has, as shown in
FIG. 10
, a first arm portion
48
, a second arm portion
49
, and a support portion
41
. The first arm portion
48
extracts a wafer as an inspection target from the cassette member
3
set on the lifting unit
2
and holds the extracted wafer. The second arm portion
49
holds the wafer inspected by the observation system
6
and
7
, and stores the inspected wafer in the cassette member
3
. The support
Hasegawa Tsuneo
Honma Kurata
Kawai Akitoshi
Komatsu Manabu
Tazawa Hisashi
Fayyaz Nashmiya
Nikon Corporation
Williams Hezron
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