Title: Substrate holding device, semiconductor manufacturing apparatus and device manufacturing method
Abstract: A substrate holding device includes a base member capable of removably holding a plate having a contact member to come into contact with a substrate, and a sensor that identifies an identification sign provided on the plate.
Patent Number: 6,982,784 Issued on 01/03/2006 to Matsui
| Inventors:
|
Matsui; Shin (Saitama, JP)
|
| Assignee:
|
Canon Kabushiki Kaisha (Tokyo, JP)
|
| Appl. No.:
|
931984 |
| Filed:
|
September 2, 2004 |
Foreign Application Priority Data
| Mar 10, 2000[JP] | 2000-066378 |
| Feb 16, 2001[JP] | 2001-040169 |
| Current U.S. Class: |
355/72; 355/75 |
| Current Intern'l Class: |
G03B 27/58 (20060101); G03B 27/62 (20060101) |
| Field of Search: |
355/30,53,72-76
310/10,12.FOS
378/34-35
|
References Cited [Referenced By]
U.S. Patent Documents
| 4601560 | Jul., 1986 | Isohata et al.
| |
| 4755747 | Jul., 1988 | Sato.
| |
| 4869481 | Sep., 1989 | Yabu et al.
| |
| 5220171 | Jun., 1993 | Hara et al.
| |
| 5329126 | Jul., 1994 | Amemiya et al.
| |
| 5382311 | Jan., 1995 | Ishikawa et al.
| |
| 5409348 | Apr., 1995 | Suzuki.
| |
| 5471279 | Nov., 1995 | Takizawa.
| |
| 5706843 | Jan., 1998 | Matsuo.
| |
| 5981966 | Nov., 1999 | Honma.
| |
| 5999589 | Dec., 1999 | Chiba et al.
| |
| 2002/0176096 | Nov., 2002 | Sentoku et al.
| |
| Foreign Patent Documents |
| 7-130637 | May., 1995 | JP.
| |
| 2748181 | Feb., 1998 | JP.
| |
Primary Examiner: Nguyen; Henry Hung
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto
Parent Case Text
This application is a divisional application of U.S. patent application Ser.
No. 09/799,060, filed Mar. 6, 2001, now U.S. Pat. No. 6,862,080.
Claims
What is claimed is:
1. A substrate holding device comprising:
a base member capable of removably holding a plate having a contact member to
come into contact with a substrate;
a sensor that identifies an identification sign provided on said plate; and
a controller that selects the plate based on an identification signal from said
sensor, wherein said controller selects said plate based on information on a type
of the substrate.
2. The substrate holding device according to claim 1, further comprising a storage
device in which a status of use of said plate is stored based on an identification
signal from said sensor.
3. The substrate holding device according to claim 1, wherein the information
on the type of the substrate is outputted based on a signal indicative of an exposure condition.
Description
FIELD OF THE INVENTION
The present invention relates to a substrate holding device for holding a substrate
(wafer) and an aligner or a semiconductor device manufacturing method using the
substrate holding device.
DESCRIPTION OF THE RELATED ART
With the advance of semiconductor device miniaturization, attachment of foreign
materials to the rear surface of a semiconductor substrate such as a wafer, contamination
of a wafer chuck, and the like, cause defects of semiconductors and seriously degrade
productivity. In a semiconductor fabrication process, to prevent attachment of
foreign materials to the rear surface of a semiconductor substrate, on the substrate
side, cleaning which is called a back rinse is performed, and on the fabrication
apparatus side, the shape, material and the like of the chuck are improved, so
as to prevent attachment of foreign materials.
However, as the rear surface of a semiconductor substrate is handled upon
transfer, a complete prevention measure has not been found so far.
In a semiconductor substrate process, most of foreign materials attached to the
wafer chuck of an aligner are photosensitive material (photoresist) attached to
the rear surface of the semiconductor substrate. The photosensitive material attached
to the chuck solidifies on the wafer chuck. Further, floating dust in an atmosphere
around the apparatus may be accumulated.
A problem occurs in the semiconductor fabrication process especially when the
above-described
solidified photosensitive material attaches to the chuck. This cannot be removed
by a simple cleaning operation.
To remove the solid foreign material attached to the chuck, it is necessary to
remove the wafer chuck from the apparatus and scrape the material away with a sharp-edged
tool. However, if a knife-edged cutlery, a file or the like is used, the surface
of the wafer chuck requiring 0.1 μm order flatness precision may be damaged
or the surface precision may be degraded. Accordingly, for wafer chuck cleaning,
a special tool is made as a flat plate with a surface precision approximately the
same as that of the wafer chuck, having plural grooved sharp edges, and the grooved
surface is brought into contact with the chuck to be cleaned, such that the foreign
material attached to the chuck surface is scraped away.
FIG. 10 shows a conventional wafer chuck (Publication of Japanese Patent No. 2748181).
In FIG. 10, a reference numeral 115 denotes a wafer chuck; and 116,
suction grooves to suction-hold almost the entire surface of a wafer. As shown
in this figure, generally, a conventional wafer chuck has a thickness of several
mm to several tens of mm. This thickness is the minimum thickness necessary to
maintain the flatness of the chuck. An extremely thin wafer chuck cannot be made
without difficulty.
At present, in the semiconductor fabrication process, a maintenance operator
manually
removes a substrate holding unit (wafer chuck) from the apparatus and performs
cleaning at regular intervals (or at irregular intervals). However, it takes much
time for chuck exchange, or the apparatus must be stopped for a predetermined period
due to the problem of temperature stability of the apparatus or the like. This
problem is one of the factors of degradation of productivity.
Further, as one prevention measure against the problem, means for cleaning
the wafer chuck on the apparatus has been proposed (Japanese Patent Laid-Opened
No. 7-130637). However, it cannot be considered as the best measure from the viewpoint
of preservation of a clean environment in the apparatus.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the above problems of
the conventional techniques, and has as its object to provide a semiconductor manufacturing
apparatus which enables simple attachment/removal of substrate holding means such
as a chuck and cleaning of the substrate holding means, and which attains high productivity.
According to the present invention, the foregoing object is attained by
providing a substrate holding device comprising: a base member capable of removably
holding a plate having a contact member to come into contact with a substrate;
a first attraction mechanism that attracts the substrate onto the plate in a status
where the plate is held on the base member; and a second attraction mechanism that
attracts the plate onto the base member.
Other features and advantages of the present invention will be apparent from
the following description taken in conjunction with the accompanying drawings,
in which like reference characters designate the same name or similar parts throughout
the figures thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of
the specification, illustrate embodiments of the invention and, together with the
description, serve to explain the principles of the invention.
FIG. 1 is a cross-sectional view of a substrate holding device according to
a first embodiment of the present invention;
FIG. 2 is an exploded perspective view showing the structure of the substrate
holding device according to the first embodiment;
FIGS. 3A and 3B are explanatory views showing the positional relation between
a projection of a plate and that of a base member;
FIG. 4 is a perspective view showing the structure of a substrate conveyance
device according to the first embodiment;
FIGS. 5A and 5B are flowcharts showing a sequence upon attachment of the plate
and a sequence upon removal of the plate, according to the first embodiment;
FIG. 6 is a cross-sectional view of the substrate holding device according to
a second embodiment of the present invention;
FIG. 7 is a schematic view of a semiconductor aligner according to a third embodiment
of the present invention;
FIG. 8 is a flowchart showing semiconductor device fabrication;
FIG. 9 is a flowchart showing a wafer process; and
FIG. 10 is a partial-cutaway schematic perspective view of the conventional
substrate holding device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the present invention will now be described in
detail in accordance with the accompanying drawings.
<First Embodiment>
FIG. 1 is a cross-sectional view showing the structure of a substrate holding
device (wafer chuck) of a semiconductor manufacturing apparatus according to a
first embodiment of the present invention. FIG. 2 is an exploded perspective view
showing respective parts of the substrate holding device in FIG. 1.
The substrate holding device of the present embodiment is held on a drive mechanism
called a wafer stage to sequentially transfer a circuit pattern on a reticle onto
a semiconductor substrate (wafer). The wafer stage is capable of positioning in
XYZ translation directions and XYZ axial rotation directions by a drive mechanism.
Note that other functions than the substrate holding device are omitted.
Numeral
1 denotes a base member fixed on the wafer stage (not shown).
The base member
1 has a temperature control channel
6 to maintain
a constant temperature of the member, and a temperature control medium is circulated
through the channel. Note that in a case where the temperature of the substrate
holding base is increased by heat upon exposure or heat from the drive mechanism,
a coolant is used. Further, as the temperature control medium, pure water, oil
or the like is used.
Numeral
2 denotes a plate held on the base member
1, for directly
holding a wafer
3. Upon chuck cleaning, only the plate
2 is removed
and is cleaned. This operation will be described in detail later.
The plate
2 is vacuum-sucked on the base member
1 by negative pressure
in a gap between the base member
1 and the plate
2 caused by a plate
suction mechanism
4. For this purpose, the base member
1 has a plate
suction hole
15.
Numeral
5 denotes a wafer suction mechanism to vacuum-suck the wafer
on the plate
2. The wafer suction mechanism
5 is provided on the
base member
1. Note that as a piping from the wafer suction mechanism
5
to the wafer, a wafer suction hole
14 is formed through the base member
1 and the plate
2 for holding the wafer
3 on the plate
2
by vacuum suction. That is, the plate
2 is placed on the base member
1
while the plate is aligned with the base member such that the suction hole provided
in the plate
2 and the suction hole provided in the base member
1
are aligned with each other.
Even in a status where the wafer is not placed on the plate
2, it is
preferable that the plate
2 is sucked to the base member
1. For this
purpose, in the present embodiment, the plate suction mechanism
4 and the
wafer suction mechanism
5 function independently of each other.
In the present embodiment, the vacuum suction mechanism is used for holding the
wafer
3 and the plate
2, however, the present invention is not limited
to the vacuum suction mechanism but any other holding mechanism such as an electrostatic
chuck or a mechanical chuck can be used to obtain a similar advantage. In use of
the electrostatic chuck to hold the wafer
3, the plate
2 is placed
on the base member
1 while the plate is aligned with the base member such
that an electrode provided in the plate
2 and an electrode provided in the
base member
1 are aligned with each other.
Numeral
7 denotes wafer contact pins for holding the wafer
3
on the plate
2. Further, numeral
2a denotes a ring-shaped
contact member provided on a rim of the plate
2. The wafer
3 is supported
by the contact member
2a and the pins
7, and is flat-corrected.
Numeral
8 denotes plate contact pins as contact members for holding the
plate
2 on the base member
1. Numeral
1a denotes a
ring-shaped contact member provided on a rim of the base member
1. The plate
2 is supported by the contact member
1a and the pins
8.
In the present embodiment, to reduce the footprint and avoid attachment of dust,
the pin-shaped projections are used as the respective contact members. Note that
the contact members are not limited to the pin-shaped projections but any other
members such as ring-shaped projections may be used as long as they attain a similar
advantage. Further, even if the projections on the plate are pin-shaped projections,
ring-shaped projections may be used on the base member.
FIG. 3A shows the positional relation between the pins
7 provided on
the plate
2 and the pins
8 provided on the base member
1.
FIG. 3B shows a positional shift amount d between the central axis of the projection
on the plate
2 (e.g., pin
7) and that of the projection on the base
member
1 (e.g., pin
8).
It is impossible to form the plate
2 as a complete solid body. The plate
2 has a characteristic as an elastic body. Accordingly, when negative pressure
occurs between the base member
1 and the plate
2 or between the plate
2 and the wafer
3, for example, the plate
2 is elastically
deformed. However, even when the plate
2 is elastically deformed, the flatness
of the surface of the pins
7 holding the wafer
3 must be maintained
so as to flat-correct the wafer
3.
It is desirable that the projections on the base member
1 (e.g., pins
8)
be provided under projections of the plate
2 (e.g., pins
7) as shown
in FIG. 3A.
That is, it is desirable that as the positional relation between the projections
on the plate
2 and those on the base member
1, they are coaxially
arranged as much as possible. Here "coaxial" does not mean complete coaxial positioning
but positioning such that the degradation of flatness caused in the plate
2
due to the positional shift d is within an allowable range. For example, if the
positional shift d is equal to or less than 5 mm, the projections are coaxially
positioned, and if the positional shift d is equal to or less than 1 mm, the projections
are more preferably coaxially positioned, and further, if the positional shift
d is equal to or less than 0.5 mm, the projections are further preferably coaxially
positioned. In any case, if the flatness of the plate
2 is within the allowable
range, the projections are in the "coaxial" relation. Further, it may be arranged
such that the projections are in the "coaxial" relation if the central axis of
the projection on the plate
2 is within the area of the projection of the
base member
1.
Further, it is preferable that the projections on the base member
1
are arranged under all the projections on the plate
2. Note that the projections
are not necessarily arranged in this manner. It is preferable that the projections
on the base member
1 are provided under 90% of the projections on the plate
2.
Note that in the use of an electrostatic chuck, the above advantage can be similarly
obtained even if the projections are not used.
Next, the structure for plate conveyance to automatically attach/remove the
plate to/from the base member by the above construction will be described with
reference to FIG. 4.
Numeral
13 denotes the wafer stage which is not shown in FIGS. 1 and
2. The wafer stage
13 is capable of positioning in the XYZ translation directions
and the XYZ axial rotation directions by a wafer stage device mechanism
22.
A bar mirror
11 as well as the above-described wafer chuck is mounted on
the wafer stage
13. The bar mirror
11 is irradiated with a laser
beam (interferometer beam)
12, thereby the position of the reflection surface
of the bar mirror
11 is measured. That is, the position of the wafer stage
13 is measured by a laser interferometer (not shown) and the bar mirror
11. The result of the measurement is inputted into a controller
21.
The controller
21 outputs a drive signal to the wafer stage drive mechanism
22 based on the input position information of the wafer stage
13.
The drive mechanism
22 drives the wafer stage
13 based on the drive signal.
Numeral
9 denotes a hand for conveyance used for providing/collecting
the wafer
3 and for providing/collecting the plate
2. The hand
9
grasps a side surface of the wafer
3 or the plate
2 by a grasp mechanism
10 included in the end of the hand
9. The grasp mechanism
10
is controlled based on a signal from the controller
21. Further, a Z drive
mechanism
25 drives the hand
9 in the Z direction. The Z drive mechanism
25 is controlled based on a signal from the controller
21. By using
the Z drive mechanism
25, the wafer or plate grasped by the hand
9
can be placed on the base member or the like, or the placed wafer or plate can
be removed. In the present embodiment, an edge portion of the wafer
3 and
that of the plate
2 is grasped. Note that pickup/placement upon conveyance
is not limited to the grasp of the side surface. For example, it may be arranged
such that the wafer
3 is lifted in the Z direction from the plate
2
or the plate
2 is lifted in the Z direction from the base member
1,
and the hand holds the bottom surface of the wafer
3 or the plate
2.
Note that a hand drive mechanism
23 is provided to drive the hand
9
in the Z or Y direction to, e.g., convey the wafer
3 and the plate
2
to the outside of the exposure chamber. The drive mechanism
23 drives the
hand
9 based on a signal from the controller
21.
FIG. 5A shows a sequence upon attachment of the plate
2 in the above
construction, and FIG. 5B shows a sequence upon removal of the plate. The controller
21 controls necessary drive mechanisms and the like based on the sequences.
In an initial status, the plate
2 and the wafer
3 are not placed
on the base member
1. To set the plate
2 from this initial status,
first, a plate to be attached is designated from plural plates (a
1). The
designation of the plate is made, e.g., by inputting a signal into the controller
21 or based on stored exposure information. Then, it is checked that the
plate
2 and the wafer
3 are not placed on the base member (a
2
and a
3). The checking operation is made based on, e.g., signals from pressure
sensors provided in the plate suction mechanism
4 and the wafer suction
mechanism
5. Thereafter, the designated plate is conveyed from a plate carrier
(not shown) (also usable as a wafer carrier) to the status as shown in FIG. 4 (a
4).
When the plate
2 has been conveyed to a position above the base member
1, the plate
2 is moved downward and brought into contact with the
base member
1 by the Z drive mechanism
25 (a
5). When the contact
between the plate
2 and the base member
1 has been checked, the plate
suction mechanism
4 is changed to a sucking status, to suction-hold the
plate
2 and the base member
1 (a
6). The suction between the
base member
1 and the plate
2 is made by vacuum suction here.
When the suction status has been checked, the hand
9 changes the grasp
mechanism
10 to a non-suction status (a
7), to withdraw the hand
9
(a
8). Thus, the placement of the plate is completed (a
9).
Further, when the plate is removed, it is checked that the plate
2
exists but the wafer
3 does not exit, and the above operations are made
in the reverse order.
That is, first, it is checked that the wafer does not exist on the plate but
the plate
2 exists on the base member (b
1 and b
2). The conveyance
hand
9 is moved to hold the plate side surface (b
3), and the grasp
mechanism
10 of the conveyance hand
9 is changed to a grasping status
(b
4). The plate suction mechanism is released to change the plate into unsucked
status (b
5), and the hand
9 is moved upward by the Z drive mechanism
25, to separate the plate
2 from the base member
1 (b
6),
into the status as shown in FIG. 4. Thereafter, the plate
2 is conveyed
onto the plate carrier (not shown).
Note that the plate
2 is previously processed so as to have an ultra-flat
surface when placed on the base member
1. If there is a probability that
dust is held between the plate and the base member upon attachment/removal, it
is more preferable to provide a function or mechanism to check the flatness after
the attachment/removal of the plate.
To correct the wafer-contact surface of the plate
2 to be ultra flat,
it
is preferable that the base member
1 and the plate
2 respectively
have ultra-flat surfaces. Actually, as there is a process limit, it is difficult
to attain a complete precision regarding surface distortion. In ultra-flatness
processing, precision is obtained by grinding or lapping. In this case, as slight
inner stress occurs in the processed workpiece, a thin plate as in the present
embodiment is distorted. Note that regarding thickness unevenness, such a problem
does not occur. Therefore, high-precision thickness control can be made.
In the present embodiment, the base member
1 has an ultra-flat surface,
and the thickness of the plate
2 is controlled, such that the base member
1 flatten-corrects the plate
2. Accordingly, even if the plate
2
itself has slight distortion, the wafer-contact surface of the plate
2 can
be corrected to be flat by suctioning the plate
2 to the base member
1.
For example, if the surface of both members are vacuum-suctioned to each other
in an area of ø300 mm (the area of the suctioned surfaces is about 707 cm
2),
the suction can be made by a force of 707 kgf at the maximum, and this force can
be utilized for correcting the distortion of the plate.
On the other hand, when the surface of the plate
2 is flatten-corrected
by the base member
1, the base member
1 receives a force to distort
the base member. However, if the base member is distorted by an amount exceeding
the allowable range, the function to correct the flat surface of the wafer is finally degraded.
It is desirable that the rigidity of the base member
1 is greater than
that of the plate
2. For example, assuming that the rigidity of the plate
2 is "1", the rigidity of the base member
1 is desirably "2" or greater.
Generally, the focal depth assigned to wafer surface precision in a semiconductor
exposure process is 2 μm or less (λ=0.365, NA=0.3, k=1, and if the
assignment to the wafer surface precision is 50%, (λ/NA
2)×k×0.5),
the limitation of the plate flattening process is 4 μm (e.g., ø150 mm).
The relation of rigidity between the plate
2 and the base member
1
is the ratio of rigidity required of the base member
1 in this case (here
the surface shape of the base member
1 is ignored for the sake of simple
explanation). Note that the relation between the process precision and the ratio
of rigidity (rigidity of plate
2/rigidity of base member
1) and the
flatness of the plate
2 after flattening-correction is as follows.
Process precision×rigidity ratio=flatness of plate
2 after flattening-correction.
Accordingly, as a thin plate (e.g., having a thickness of a wafer) is
generated, even if the plate
2 has distortion, the contact surface of the
plate
2 can be ultra flat by suction-holding the plate to the base member
having sufficient rigidity.
Note that even if the focal depth is reduced in the future, the flattening-correction
can be made by increasing the rigidity of the base member with respect to the plate
rigidity. Further, if the base member has a rigidity higher than that of the plate,
the flatness of the flatten-corrected plate
2 can be increased.
Desirably, assuming that the rigidity of the plate
2 is "1", the
rigidity of the base member
1 is "10" or greater. More desirably, assuming
that the rigidity of the plate
2 is "1", the rigidity of the base member
1 is "20" or greater.
Note that the plate
2 is removed from the base member in accordance with
a predetermined sequence. As timing of the removal of the plate
2 from the
base member
1, {circle around (1)} when contamination of the plate is detected
and the contamination level is higher than a predetermined reference level, the
plate is removed to be exchanged with another plate; {circle around (2)} when a
predetermined period has elapsed since the plate was set on the base member, the
plate is removed to be exchanged with another plate; or {circle around (3)} when
the substrate holding device is applied to an aligner, the plate is removed in
accordance with an exposure history.
Foreign materials attached to the plate
2 are removed by a cleaner
(not shown), and the plate
2 is reused. Further, it is desirable to provide
a device to detect foreign materials attached to the plate to be utilized, and
it is further desirable to provide a device to detect smoothness, flaws and the
like of the plate.
Note that if another plate is used while the removed plate is cleaned, production
is continued without suspension during the cleaning.
Further, as the projections of the base member
1 are to be positioned
under the projections of the plate
2, the plate
2 must be aligned
with the base member
1. Accordingly, similar to a notch
18 of the
wafer or an orientation/flat aligner, an alignment reference mark
19 such
as a notch or orientation/flat aligner is formed in the plate such that alignment
is made upon conveyance of the plate as in the case of a wafer. Note that the alignment
between the plate
2 and the base member
1 is not limited to this
method, but any other alignment reference mark may be provided. For example, an
alignment mark may be formed on the plate
2, or a target for magnetic detection
may be provided to detect the relative position of the plate
2 to the base
member, or the plate
2 may have an edge so as to be measured from the base
member
1. In this case, it is desirable to provide a sensor to detect the
alignment reference mark. Note that the sensor may be provided on the base member
1.
Further, it is more desirable that in consideration of a process where local
surface precision of the plate influences pattern precision, plates used in exposure
are managed by barcode
16 or inscription. Note that management is not only
made by barcode or inscription but may be made by any sign for identifying the
plate. In this case, it is necessary to provide an identification sensor
20
to identify the sign provided on the plate. Further, it is desirable to provide
a storage device
24 for storing a status of use of a plate based on an identification
signal from the identification sensor. Then, based on information stored in the
storage device, the controller
21 controls an exposure process and other processes.
Further, as the plate
2 is brought in direct contact with the wafer,
the plate is desirably made of a ceramic (e.g., SiC, SiN) material. Further, the
substrate holding base member to hold the plate
2 is desirably made of ceramic material.
As to a temperature difference between the plate
2 that has been conveyed
from outside of the exposure chamber and the apparatus, a cooling mechanism (cooling
channel
6) included in the base member
1 performs temperature control
in a short period. Note that to effectively control the temperature of the plate
2 by the base member
1, thermal transfer from the base member
1
to the plate
2 can be increased by filling gas in the space suctioning both
members to each other. That is, the pressure of the gap between the base member
1 and the plate
2 is controlled to an extent to which the plate
2
can be suctioned, so as not to attain a vacuum state where almost no gas exists
in the gap. For this purpose, to control the pressure of the gap between the base
member
1 and the plate
2, the plate suction mechanism
4 desirably
has a pressure regulating mechanism (not shown) and a pressure sensor (not shown).
The controller
21 inputs a signal regarding the pressure outputted from
the pressure sensor, and controls the pressure regulating mechanism based on the
pressure signal. As the pressure regulating mechanism, a throttle or the like can
be used. The pressure can be controlled by controlling the opening area of the throttle.
Next, upon placement of the wafer from this status, the wafer is conveyed by
a conveyance device (not shown) from the wafer carrier (not shown) in a similar
manner to that of the conveyance of the plate
2.
The wafer
3 is conveyed to a position above the plate
2, then the
wafer is moved downward by the Z drive mechanism
25, into contact with the
plate
2. When the contact has been checked, both members are suction-held
by changing the wafer suction mechanism
5 in FIG. 1 to a suctioning status.
The wafer and the plate are suction-held by vacuum suction.
When the suction status has been checked, the grasp mechanism
10 in the
hand
9 is changed to a non-grasping status, and the hand
9 withdraws,
thus plate placement is completed. Further, when the wafer is removed, the above
operation is made in the reverse order.
Note that the plate
2 and the wafer
3 are conveyed by the same
conveyance device, however, they may be conveyed by different conveyance devices
depending on the system.
In the present invention, the plate, which may be contaminated due to attachment
of photosensitive material or the like upon contact with the wafer, can be replaced
with another plate. Accordingly, in comparison with the conventional art, the time
to remove the contaminants is not required, and the productivity can be improved.
Further, as the plate on the flat plate can be removed, cleaning to remove
the contaminants can be easily made.
<Second Embodiment>
FIG. 6 is a cross-sectional view showing the structure of the substrate holding
device (wafer chuck) of the semiconductor manufacturing apparatus according to
a second embodiment of the present invention.
In a case where wafers having different diameters such as a ø300 mm (12
inch)
wafer and a ø200 mm (8 inch) wafer are exposed by a single apparatus, conventionally,
a wafer chuck for the ø300 mm wafer must be exchanged with a wafer chuck for
the ø200 mm wafer. On the other hand, in the present embodiment, wafers having
various diameters can be handled only by changing the plate shape to have a convexity
as shown in FIG. 6. That is, in the present embodiment, the area of the plate to
suction-hold can be changed by appropriately changing the plate.
If only the plate
32 is changed in correspondence with the wafer diameter
that is changed, automatic exchange by the conveyance mechanism as shown in FIG.
4 can be realized, thus working time can be greatly reduced.
That is, the type of wafer to be held is specified from an exposure condition
inputted into the controller
21 or stored in the memory (not shown) of the
controller
21. Then the controller
21 designates a plate to be sucked
on the base member
1 based on the specified wafer type. The identification
of the plate at this time may be made by using an identification sign such as a
barcode provided on the plate. Note that attachment/removal of the plate thereafter
is made in the same manner as that described in the first embodiment.
Although the vacuum suction is used as an attraction mechanism of the base
member
1 and the plate
2 (
34) in the above first and second
embodiments, other mechanisms such as electrostatic attraction, magnetic attraction
and mechanical fixing may be used.
<Third Embodiment>
Next, an embodiment of a scanning aligner where the substrate holding device
of the first or second embodiment is mounted on a wafer stage will be described
with reference to FIG. 7.
A mirror platen
96 is supported by a floor or base
91 via a damper
98. Further, the mirror platen
96 supports a reticle stage platen
94 and supports a projection optical system
97 positioned between
a reticle stage
95 and a wafer stage
93.
The wafer stage
93 is supported on a stage platen
92 supported
by the floor or base
91, for carrying and positioning the wafer. Further,
the reticle stage
95, supported on the reticle stage plate
94 supported
by the mirror platen
96, is movable while carrying a reticle having a circuit
pattern. Exposure light to expose the reticle mounted on the reticle stage
95
is emitted from an illumination optical system
99.
Note that the wafer stage
93 is scanned in synchronization with the reticle
stage
95. While the reticle stage
95 and the wafer stage
93
are scanned, the positions of these stages are continuously detected respectively
by interferometers, and fed back to driving units of the reticle stage
95
and the wafer stage
93. This attains accurate synchronization between the
scan start positions of these stages and high-precision control on scanning speed
in a constant-speed scan area. While these stages are scanned with respect to the
projection optical system
97, the reticle pattern is exposed and thus the
circuit pattern is transferred onto the wafer.
<Fourth Embodiment>
Next, an embodiment of the semiconductor device manufacturing method utilizing
the above aligner will be described. FIG. 8 shows a flow of a fabrication of a
semiconductor device e.g., a semiconductor chip such as an IC or an LSI or a liquid
crystal panel, a CCD or the like). At step S
1 (circuit design), a circuit
design of the semiconductor device is made. At step S
2 (mask fabrication),
a mask where the designed circuit pattern is formed is fabricated. At step S
3
(wafer fabrication), a wafer is fabricated by using material such as silicon. At
step S
4 (wafer process) called a preprocess, the mask and the wafer are
used for forming an actual circuit on the wafer by lithography. At step S
5
(fabrication) called a post process, the wafer fabricated at step S
4 is
used for forming a semiconductor chip. The step S
5 includes an assembly
process (dicing and bonding), a packaging process (chip encapsulation) and the
like. At step S
6 (inspection), inspections such as an operation test and
an endurance test are performed on the semiconductor device fabricated at step
S
5. Through these processes, the semiconductor device is completed and shipped
(step S
7).
FIG. 9 shows the wafer process in detail. At step S
11 (oxidation), the
surface of the wafer is oxidized. At step S
12 (CVD), an insulating film
is formed on the surface of the wafer. At step S
13 (electrode formation),
an electrode is formed by vapor-deposition on the wafer. At step S
14 (ion
implantation), ions are implanted into the wafer. At step S
15 (resist processing),
a photoresist is applied to the wafer. At step S
16 (exposure), the circuit
pattern on the mask is expose-printed on the wafer by the above aligner. At step
S
17 (development), the exposed wafer is developed. At step S
18 (etching),
the portions other than the developed resist image are removed. At step S
19
(resist stripping), the unnecessary resist after the etching was removed. These
steps are repeated until a multiple circuit pattern is formed on the wafer. By
using the fabrication method of the present embodiment, the conventionally low-efficient
device fabrication process can be improved.
According to the substrate holding device of the present invention, as
the plate can be removed and cleaned, time to remove contaminants is not required.
Thus, the productivity can be improved. Further, as the plate on the flat plate
can be removed, cleaning to remove the contaminants can be easily performed.
The present invention is not limited to the above embodiments and various changes
and modifications can be made within the spirit and scope of the present invention.
Therefore, to appraise the public of the scope of the present invention, the following
claims are made.
*
