Photocopying – Projection printing and copying cameras – Step and repeat
Reexamination Certificate
2002-05-21
2004-03-16
Fuller, Rodney (Department: 2851)
Photocopying
Projection printing and copying cameras
Step and repeat
C355S067000
Reexamination Certificate
active
06707535
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device for exposing a peripheral area which exposes the peripheral area of a wafer in order to remove a photoresist which has been applied to the surface of a semiconductor wafer in the peripheral area of the wafer, wherein the outside peripheral area of the semiconductor wafer is provided with a V-shaped notch.
2. Description of the Related Art
A conventional device for exposure of a peripheral area is described below using
FIG. 8
,
FIG. 9
, FIG.
10
A and FIG.
10
B.
FIG. 8
illustrates a schematic of the arrangement of a conventional device for exposure of a peripheral area.
FIG. 9
shows a schematic of the arrangement of a controller of a conventional device for exposure of a peripheral area.
FIG. 10A
shows a state in which the peripheral area of a wafer is exposed by a conventional device for exposure of a peripheral area.
FIG. 10B
shows the exposure state of a notch area by a conventional device for exposure of a peripheral area.
In a light source device, there is a lamp
11
which emits light containing UV radiation, for example, a super-high pressure mercury lamp with a nominal wattage of 250 W. The radiant light from this lamp
11
is focused with a focusing mirror
12
on the incidence end face
13
a
of optical fibers
13
. Between the lamp
11
and the incidence end face
13
a
of the optical fibers
13
, there is a shutter
14
which is opened or closed by the drive of a shutter drive device
15
.
When a shutter OPEN signal is sent from the operating part of the CPU within the controller
50
to the part MD
3
for driving the shutter drive device, the part MD
3
drives the shutter drive device
15
, the shutter
14
opens and the light focused by the focusing mirror
12
is incident on the incidence end face
13
a
of the optical fibers
13
and is emitted as exposure light with a stipulated irradiation area S from an exposure light irradiation part
2
which is installed on the exit end face
13
b
of these optical fibers
13
.
The exposure light irradiation part
2
is located integrally with a means
4
for edge determination (detailed below) and is movably held by a device
3
for moving the means for edge determination in the direction which is essentially perpendicular to a tangent to the edge E of the wafer W, i.e. essentially in the direction to the wafer center O (in the two directions D of the arrow in FIG.
8
). The exposure light emitted from the exposure light irradiation part
2
with the stipulated exposure area S moves therefore in the same direction and by the same amount as the means
4
for edge determination.
The wafer W with an outside peripheral area which is provided with a notch N and to which a photoresist R has been applied is placed on a treatment stage
6
. The wafer W is attached by an attachment means which is not shown in the drawings, for example by vacuum suction. The treatment stage
6
is rotationally held by a treatment stage rotation device
61
.
When a stage rotary start signal is sent from the operating part of the CPU within the controller
50
to the part MD
4
for driving the treatment stage rotation device, the part MD
4
drives the treatment stage rotation device
61
and, based on the data which was input into the input part
7
, such as the speed of rotation, the angle of rotation, the frequency of rotation and the like, starts rotation of the treatment stage
6
.
The sequence of exposure of the peripheral area of the wafer in a conventional device for exposing a peripheral area is described as follows. First, the wafer W with an outside peripheral area provided with a notch N and to which a photoresist R has been applied is transported by a wafer transport and placement means (not shown in the drawings) and placed on the treatment stage
6
in a state in which the middle O of the wafer W and the center of rotation of the treatment stage
6
essentially agree with one another.
Next, if an exposure width adjustment start signal is sent from the operating part of the CPU within the controller
50
to the part MD
2
for driving the exposure width adjustment device, the part MD
2
, based on data of the exposure width A (the width to be exposed proceeding from the edge E of the wafer W) which were input beforehand into the input part
7
, drives the exposure width adjustment device
8
and moves the area S irradiated with the exposure light to a given position (position at which the area with the width A proceeding from the edge E of the wafer W can be exposed when the means
4
for edge determination described below captures (determines) the edge E of the wafer W).
Next, if a wafer edge determination start signal is sent from the operating part of the CPU within the controller
50
to the part MD
1
for driving the device for moving the means for edge determination, the part MD
1
drives the device
3
for moving the means for edge determination and moves the means
4
for edge determination in the direction to the wafer W. The determination of the position of the edge E of the wafer W is started by the means
4
for edge determination.
The controller
50
then drives the shutter drive device
15
when it receives a signal from a light receiving part
42
of the means
4
which shows that the edge E of the wafer W is determined. This causes the shutter
14
to open which irradiates the peripheral area of the wafer W via the exposure light irradiation part
2
with exposure light with the given irradiation area S. The controller
50
furthermore drives the treatment stage rotation device
61
almost simultaneously with opening of the shutter
14
, and exposes the peripheral area of the wafer W by turning the wafer W with a rotational speed (which is input beforehand into the input part
7
) and in an angular range (also input beforehand into the input part
7
). The controller
50
controls the device
3
for moving the means for edge determination and moves the means
4
for edge determination to a position at which the means
4
for edge determination outputs a signal to the controller
50
which shows that the edge E of the wafer W is always captured. As was described above, the area S irradiated with exposure light before exposure is moved to a position at which the area with a width A proceeding from the edge E of the wafer W can be exposed when the means
4
captures the edge E of the wafer W. Moreover, upon exposure, irradiation area S is synchronized with the means
4
and moved in the same direction and by the same amount. The peripheral area of the wafer W can therefore be exposed at the exposure width A which is constant proceeding from the edge E of the wafer W.
When exposure of the peripheral area of the wafer W is completed, the controller
50
closes the shutter
14
, ends rotation of the treatment stage
6
and furthermore returns the exposure light irradiation part
2
to the initial position.
A process for determining the wafer edge is now described. The means
4
for determining the edge E of the wafer W consists of the projection part
41
which projects sensor light and the light receiving part
42
which receives this sensor light and outputs to the controller
50
an analog signal which becomes larger or smaller depending on the amount of sensor light projected by the projection part
41
onto the light receiving part
42
. The controller
50
amplifies the above described analog signal from the light receiving part
42
by means of an amplifier AC
1
. For example, in the case of complete shielding by the wafer W which has been placed on the treatment stage
6
, a signal which is obtained is amplified to −5 V and, in the case of no shielding at all, a signal which is obtained is amplified to +5 V.
The above described voltage signal which was amplified in the above described amplifier AC
1
is computed in a PID circuit PC and a control signal which is used to make the above described voltage signal into a constant voltage is output to the part MD
1
for driving the device for moving the means for edge d
Sato Masanori
Shindo Yutaka
Fuller Rodney
Nixon & Peabody LLP
Safran David S.
Ushiodenki Kabushiki Kaisha
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