Photocopying – Projection printing and copying cameras – Step and repeat
Reexamination Certificate
1997-12-05
2001-04-24
Mathews, Alan A. (Department: 2851)
Photocopying
Projection printing and copying cameras
Step and repeat
C355S072000, C355S075000, C074S490100
Reexamination Certificate
active
06222614
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an exposure apparatus for making semiconductor devices and liquid crystal display devices and, in particular, to an XY stage section of such an exposure apparatus.
2. Related Background Art
In order to make semiconductor devices and liquid crystal display devices, there has been employed an exposure apparatus for exposing a photosensitive substrate such as semiconductor wafer or glass plate to a pattern of a reticle or mask (hereinafter referred to as mask). As a means for moving the photosensitive substrate to a predetermined exposure position, the exposure apparatus includes a stage unit equipped with a substrate stage which is movable in two-dimensional directions of X and Y.
FIG. 9
is a conceptual view of a conventional stage unit. A substrate stage
71
having a substrate-mounting surface on its upper side is freely moved, by means of a driving section, over a base
72
along non-depicted guides for XY directions. A photosensitive substrate is mounted on the substrate-mounting surface of the substrate stage
71
, and is attached thereto and held thereby as being vacuumed through a vacuum hole (not depicted) formed in the substrate-mounting surface. For such a kind of stage moving mechanism, the technique disclosed in U.S. Pat. No. 4,535,278 can be used.
Connected to the substrate stage
71
are cables for supplying electric power to driving means such as motor disposed within the substrate stage, a coolant pipe for cooling the motor, a coolant pipe for keeping the substrate stage at a predetermined temperature, a vacuum pipe for evacuating the vacuum hole formed in the substrate-mounting surface, and the like (these cables and pipes being collectively referred to as cables hereinafter). These cables
73
are secured to a securing section
73
a
of the substrate stage
71
and a securing section
73
b
within the apparatus. As the cables
73
deform between the securing sections
73
a
and
73
b,
the substrate stage
71
is allowed to freely move above the base
72
.
FIGS. 10
to
12
schematically illustrate various states of the cables
73
when the substrate stage
71
is moved over the base
72
. Namely,
FIGS. 10
to
12
show states where the substrate stage
71
is positioned at the center, upper left portion, and lower right portion of the base
72
, respectively.
When the substrate stage
71
moves from the position shown in
FIG. 10
to that shown in
FIGS. 11
or
12
, while one cable securing section
73
a
securing the cables
73
moves together with the substrate stage
71
, the other cable securing section
73
b
is kept stationary. Accordingly, as the substrate stage
71
moves, the cables
73
expands and contracts between the two cable securing sections
73
a
and
73
b.
Here, as the cables
73
tend to resume their original state, a reaction force
74
indicated by depicted arrow acts on the substrate stage
71
via the cable securing section
73
a.
Since the direction and magnitude of the reaction force
74
vary depending on the state of expansion and contraction of the cables
73
, this reaction force, as disturbance, has adversely affected the positioning accuracy of the substrate stage
71
.
SUMMARY OF THE INVENTION
In view of such a problem of the conventional substrate stage, it is an object of the present invention to provide an exposure apparatus in which the positioning accuracy of its substrate stage or the like is not influenced by cables.
In order to achieve this object, the present invention provides an exposure apparatus for projecting a mask pattern of a mask onto a substrate, the exposure apparatus comprising a substrate stage which is two-dimensionally movable along an upper surface of a substrate base while carrying the substrate thereon; cable-relaying means which is disposed so as to be physically separated from the surface of the substrate base, and is movable in the same two-dimensional directions as those of the substrate stage while securing thereto a cable connected to the substrate stage; and driving means to control an amount of movement of the cable-relaying means such that relative positions of the substrate stage and the cable-relaying means with respect to each other are always kept constant.
Consequently, the cable-relaying means moves so as to follow the substrate stage, whereby the relative positional relationship between the cable-relaying means and the substrate stage is always kept constant. As a result, the cable dragged between the substrate stage and the cable-relaying means always keeps a constant form, whereby the direction and magnitude of the reaction force applied to the substrate stage by the cable are always held constant as well. Accordingly, there is no fluctuation in reaction force, whereby the stage can secure accuracy in movement.
When a reticle stage is configured to be movable, it is preferred that the reticle stage has a configuration similar to that mentioned above.
In order to prevent the stage section from being influenced upon driving the cable-relaying means, the driving section is preferably placed in an auxiliary base section which is disposed so as to be physically separated from a base main body.
REFERENCES:
patent: 4535278 (1985-08-01), Asakawa
patent: 4780617 (1988-10-01), Umatate et al.
patent: 5151750 (1992-09-01), Magome et al.
patent: 5187519 (1993-02-01), Takabayashi et al.
patent: 5467720 (1995-11-01), Korenaga et al.
patent: 5523574 (1996-06-01), Shirasu
patent: 5623853 (1997-04-01), Novak et al.
patent: 2290658 (1996-01-01), None
Foley & Lardner
Mathews Alan A.
Nikon Corporation
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