JPH10289942A - Stage device and projection aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to magnify the moving stroke of the substrate mounting surface in the direction orthogonally intersecting the shifting surface of a stage. SOLUTION: The position of a substrate stage 18 is normally controlled by the main control system based on the measured value of the first length measuring axis B1X of an interferometer, and when the placed surface of a substrate W comes down, the position of the stage 18 is controlled based on the measured value of the second length measuring axis LB2X by switching the length measuring axis of the interferometer. As a result, the position of the stage 18 can be controlled without any trouble as long as the second length measuring axis of the interferometer 24 comes off from a reflection surface 22, even when the placed surface of the substrate W is shifted downward to the degree that the first length measuring axis of the interferometer 24 comes off from the reflection surface 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stage device and a projection exposure apparatus, and more particularly, to a substrate stage on which a substrate can be placed and movable, and an interferometer system for measuring the position of the substrate stage with high accuracy. And a projection exposure apparatus using the same.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor element, a liquid crystal display element, and the like are manufactured by a photolithography process, a pattern formed on a mask (or a reticle; hereinafter, collectively referred to as “reticle” as appropriate) is projected by a projection optical system. A projection exposure apparatus, for example, a reduction projection type exposure apparatus (stepper) for transferring a wafer or glass plate or the like having a surface coated with a photoresist (hereinafter, appropriately referred to as a “wafer”) through the substrate is used.

In this type of projection exposure apparatus, it is necessary to precisely position a wafer stage on which a wafer is mounted and moved in order to position the wafer and the reticle with high accuracy. For this reason, the position of the wafer stage can be very high resolution (for example, using a laser interferometer).
It is common to measure with a resolution of about several nm).

In this laser interferometer, a laser beam from a light source is separated into a measurement beam and a reference beam by a beam splitter, and the measurement beam is projected onto a reflection surface provided on a stage or a side surface of the stage to fix the reference beam. Is projected onto a fixed mirror (reference mirror) provided at the position, and the measurement beam reflected by the reflecting surface and the reference beam reflected by the fixed mirror are almost coaxially combined by a beam splitter, and the two beams interfere with each other. Then, high-precision measurement is performed based on the interference signal by photoelectrically detecting the interference light with a detector.

[0005] By the way, higher resolution is required with the miniaturization of the pattern, and the projection optical system has a higher N.D. A. (Numerical aperture), and as shown in FIG. 7, the projection optical system PL and the wafer W
The working distance WD on the wafer side, which is the distance between the surfaces, is small. Therefore, it is difficult to secure a space for inserting the wafer loader arm 102 below the wafer W when the wafer W is lifted from the upper surface of the wafer stage 100 when replacing the wafer.

For this reason, in a recent projection exposure apparatus, FIG.
As shown in FIG. 8, the wafer stage 100 is held horizontally (FIG. 8).
(In the direction indicated by the arrow in the drawing), the wafer W is retracted from under the projection optical system PL, the wafer W is lifted by the center-up 104, and the wafer is exchanged by the arm 102.

In addition, as shown in FIG. 9, there is also known an apparatus in which the entire wafer stage 100 is lowered vertically (see an arrow in FIG. 9) to secure a clearance required for replacing a wafer W. (For example, see JP-A-64-24).
440, etc.).

[0008]

However, in the conventional example shown in FIG. 8, it is necessary to secure a stroke necessary for loading and to prevent the measurement beam of the interferometer from deviating from the reflection surface of the wafer stage. There is a disadvantage that the wafer stage 100 becomes large. That is, as shown by phantom lines in FIG. 10, the lengths L1 and L2 of the reflecting mirrors (106 and 108) originally required for exposure by the strokes P1 and P2 required for loading need to be larger. Therefore, the stage is inevitably increased in size.

For this reason, in the conventional example shown in FIG. 8, there is a disadvantage that the size of the stage is increased and the footprint of the apparatus is increased, and the horizontal movement of the wafer stage is required every time the wafer is replaced. However, there is an inconvenience that the throughput is reduced as compared with the case where the wafer exchange is performed immediately below the projection optical system PL.

On the other hand, in the conventional example shown in FIG. 9, the disadvantages such as the increase in the footprint described above can be avoided, and the horizontal movement of the wafer stage 100 at the time of replacing the wafer W becomes unnecessary. 8 also improves throughput. However, in this case, when the wafer W is replaced, the wafer stage 100 is lowered in the vertical direction. A. As the working distance progresses and the working distance further narrows,
The amount of vertical movement of the wafer stage 100 at the time of wafer exchange must also be increased accordingly. However, in this case, the measurement beam 110 from the laser interferometer does not hit the reflecting surface 106 provided on the wafer stage 100. There is a possibility that the position of the wafer stage 100 cannot be controlled.

The same problem can occur not only in the projection exposure apparatus but also in other precision equipment which requires precise positioning (position control) of the substrate stage and which needs to move the substrate stage up and down.

The present invention has been made under such circumstances, and an object of the present invention is to provide a stage capable of expanding a moving stroke of a substrate mounting surface in a direction orthogonal to a stage moving surface. It is to provide a device.

Another object of the present invention is to provide a stage apparatus which can easily perform substrate exchange in addition to the above objects.

A third object of the present invention is to provide a stage apparatus capable of managing the position, pitching and rolling of a substrate stage in a two-dimensional direction, in addition to the above objects. .

An object of the invention described in claim 4 is that even when the working distance between the projection optical system and the sensitive substrate is narrow, a sufficient space for exchanging the sensitive substrate can be secured. Another object of the present invention is to provide a projection exposure apparatus capable of preventing a reflection surface on a substrate stage and an enlargement of the substrate stage.

[0016]

According to a first aspect of the present invention, there is provided a stage device, comprising: a substrate stage (1) on which a substrate (W) is placed and is movable in at least one direction within a predetermined reference plane.
8); a first measurement axis (LB1Xa, LB1Xb) for measuring the position of the substrate stage (18) via a reflection surface (22) provided on the substrate stage (18); and the reflection surface (22). A) a second measurement axis (LB2X) projected on one side in a first axis direction orthogonal to the reference plane from the projection position of the first long axis of (ii); The position of the substrate stage (18) is managed based on the measurement value of the first measurement axis of the measuring system (24), and the mounting surface of the substrate (W) is at least a predetermined amount.
When moving to one side in the axial direction, the measurement axis of the interferometer system (24) is switched, and the position of the substrate stage (18) is managed based on the measurement value of the second measurement axis. Control means (34).

According to this, the control means usually sets:
The position of the substrate stage is managed based on the measured value of the first measurement axis of the interferometer system, and when the mounting surface of the substrate has moved to one side in the first axis direction by a predetermined amount or more, the interferometer By switching the length measurement axis of the system, the position of the substrate stage is managed based on the measurement value of the second length measurement axis. For this reason, as the first measurement axis of the interferometer system deviates from the reflection surface provided on the substrate stage, even if the mounting surface of the substrate moves to one side in the first axis direction, the second measurement axis of the interferometer system becomes As long as the measurement axis does not deviate from the reflecting surface, the position of the substrate stage can be managed without any inconvenience. In this case, if the distance between the first measurement axis and the second measurement axis is increased, the movement stroke of the mounting surface of the substrate in the first axis direction can be increased.

According to a second aspect of the present invention, in the stage device according to the first aspect, when the substrate (W) is transferred to and from a transport system (38) for transporting the substrate (W). And a substrate transfer mechanism (54) for holding the substrate (W) and relatively moving in the first axial direction with respect to the substrate stage (18).

According to this, when the substrate is transferred to and from the transfer system for transferring the substrate, the substrate transfer mechanism holds the substrate and moves relative to the substrate stage in the first axial direction. The space required for substrate exchange can be set in a short time between the substrate and the substrate stage, and substrate exchange can be easily performed. here,
By having the “substrate transfer mechanism that moves relative to the substrate stage in the first axis direction”, both the case where the substrate transfer mechanism is fixed and only the substrate stage moves, and the case where both are movable in the first axis direction. In the latter case, the substrate transfer mechanism is moved in the direction opposite to the moving direction of the substrate stage at the same time as the movement of the substrate stage in the first axial direction, so that the In the meantime, it is possible to set the space required for substrate exchange in a shorter time.

The invention described in claim 3 is the first or second invention.
In the stage device described in (1), the substrate stage (1)
8) is movable in two orthogonal directions within the reference plane, and the interferometer system (24) is configured to control the first measurement axis (LB1Xa, LB1Xb) and the second measurement axis (LB2).
X) and third measurement axes (LB1Ya, LB) orthogonal to each other
1Yb) and a fourth measurement axis (LB2Y), wherein the control means (34) is configured to control the two-dimensional direction of the substrate stage (18) based on the measurement values of the first and third measurement axes. And the pitch of the substrate stage (18) is controlled based on the measured values of the first and second measuring axes, and the substrate is controlled based on the measured values of the third and fourth measuring axes. The rolling of the stage (18) is managed.

According to this, the position of the substrate stage in the two-dimensional direction is managed by the control means based on the measured values of the first and third measurement axes of the interferometer system, and the first and second measurement axes are controlled. The pitching of the substrate stage is managed based on the measured values of the above, and the rolling of the substrate stage is managed based on the measured values of the third and fourth measurement axes. And the rolling can be managed, and when the mounting surface of the substrate moves to one side in the first axial direction by a predetermined amount or more, the control unit switches the measurement axis of the interferometer system, Second
The position of the substrate stage in the two-dimensional direction is managed based on the measured values of the measurement axis and the fourth measurement axis.

According to a fourth aspect of the present invention, there is provided a projection exposure apparatus for projecting and exposing a pattern formed on a mask (R) onto a sensitive substrate (W) via a projection optical system (PL). A stage device (11) according to any one of claims 1 to 3 is provided for positioning the sensitive substrate.

According to this, the movement stroke of the substrate mounting surface on the substrate stage in the direction orthogonal to the stage movement surface can be expanded by the operation of the stage device according to any one of claims 1 to 3. Therefore, even when the working distance between the projection optical system and the sensitive substrate is narrow, it is possible to secure a sufficient space for exchanging the sensitive substrate, etc. It is possible to prevent an increase in size.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG.

FIG. 1 shows a stage apparatus 11 according to the present invention.
Exposure exposure apparatus 10 according to one embodiment including
Is schematically shown. This projection exposure apparatus 10
Is a step-and-repeat type reduction projection exposure apparatus (so-called stepper).

The projection exposure apparatus 10 includes an illumination system 30 for illuminating a reticle R as a mask, and an XY
A reticle stage 26 which is held parallel to a plane, and which is disposed below the reticle stage 26 and whose optical axis (A
X) A projection optical system PL whose direction is set in the Z-axis direction orthogonal to the XY plane, and a two-dimensional movement that is arranged below the projection optical system PL and holds a wafer W as a substrate (and a sensitive substrate). Leveling stage 1 as a simple substrate stage
Stage device 11 having a stage 8 and a leveling stage 1
8 is provided with an interferometer system 24 for measuring the position of the device 8 and a main control system 34 for controlling the entire apparatus as a whole.

The illumination system 30 is, for example, a high-pressure mercury lamp (i-line, g-line) or an excimer laser (KrF, A
rF), an illumination optical system including a shutter for opening and closing the optical path of light, an optical integrator (fly-eye lens), an illumination system aperture stop plate (revolver), a variable blind for limiting an illumination field of illumination light, and the like. (Neither is shown). In the illumination system 30, illumination light from a light source is made uniform, speckles are reduced, and the reticle R mounted on the reticle stage 26.
Is uniformly illuminated under predetermined illumination conditions.

The reticle stage 26 is moved in a direction perpendicular to the optical axis AX of the projection optical system PL in the X direction (the horizontal direction in FIG. 1), in the Y direction (in the direction perpendicular to the paper in FIG. 1), and Z. The reticle R is configured to be able to be driven by a minute amount in the rotation direction (θ direction) around the axis.
Can be controlled in a two-dimensional plane. The reticle stage 26 holds a reticle R on which a circuit pattern is drawn on the back surface.

As the projection optical system PL, here,
A so-called double-sided telecentric device having a predetermined reduction ratio, for example, 1/5 is used. Therefore, alignment between reticle R and wafer W is performed, and projection optical system P
When the reticle R is illuminated by the illumination light from the illumination system 30 in a state where the mating surface of the wafer W with respect to L is set, the circuit pattern on the reticle R is projected and exposed on the wafer, and a reduced image of the pattern is formed. Is formed on the wafer W.

The stage device 11 includes the wafer support table 1
2, a wafer Y-axis stage (hereinafter, referred to as “Y stage”) 14 movable in the Y-axis direction,
A wafer X-axis stage (hereinafter referred to as “X-stage”) 16 movable on the X-axis in the X-axis direction;
And the leveling stage 18 mounted on the stage 6. The upper surface of the leveling stage 18 serves as a mounting surface for the wafer W, on which the wafer W is fixed by suction. X stage 16, Y stage 14
Are driven by a wafer driving device 32.

As shown in FIG. 2, the leveling stage 18 has three drive shafts 50 on the X stage 16.
a, 50b, and 50c support up and down at three different points. These three drive shafts 50a, 50b, 50
c are drive systems 52a, 52b, 52c (note that
52c is not shown because it is disposed on the rear side of the drawing), so that the leveling stage 18 can be moved independently in the Z-axis direction which is the optical axis AX direction of the projection optical system PL. And rotation around the X-axis (rolling) and rotation around the Y-axis (pitching). In the present embodiment, the leveling stage 18 can be moved up and down along a groove 20 formed inside the X stage 16, as shown in FIGS.

The leveling stage 18 is controlled by a main control system 34 via a wafer driving device 32 and driving systems 52a, 52b, 52c.

Inside the groove 20 on the X stage 16, there is provided a center-up drive mechanism 56 and a center-up 54 as a substrate transfer mechanism composed of three pins which are simultaneously driven in the Z-axis direction. I have.
The center up 54 is connected to the leveling stage 1 through three round holes provided in the leveling stage 18.
8, and supports the wafer W from below at three points. A suction portion (not shown) is provided at the upper end of each pin constituting the center-up 54 so that the wafer can be suctioned.

The center up 54 lifts the wafer W placed on the leveling stage 18 at the time of exchanging a wafer, which will be described later, so that the wafer loader arm 38 constituting the transfer system can be inserted from below.

The center-up 54 may be fixed without performing the elevating operation, and the lowering operation of the leveling stage 18 may be used to lift the wafer W from the surface of the leveling stage 18. As in the embodiment, when both the leveling stage 18 and the center-up 54 are configured to be able to move up and down, the lowering operation of the leveling stage 18 and the ascending operation of the center-up 54 are performed simultaneously in a shorter time. Since the space in which the arm 38 can be inserted can be set, the wafer exchange time can be shortened, which is desirable.

Further, both the end surface in the + X direction and the end surface in the + Y direction of FIG. 3 of the leveling stage 18 are mirror-finished, and reflection surfaces 22 and 21 are formed respectively. The reflecting surface 22 is orthogonal to the X direction, and the pair of measuring beams LB1Xa and LB1Xb of the first measuring axis and the measuring beam LB2X of the second measuring axis of the interferometer system 24 are perpendicular to the reflecting surface. Has been projected. Among them, the measurement beams LB1Xa and LB1Xb are projected at the same height position in the Z direction of the reflection surface 22 and at a distance of L / 2 from the X axis passing through the optical axis of the projection optical system PL, respectively.
B2X is projected at a position on the X-axis passing through the optical axis of the projection optical system below the projection position of the measurement beams LB1Xa and LB1Xb by a distance d in the Z-axis direction. The distance d is, for example, 10
It is about several mm.

The reflecting surface 21 is orthogonal to the Y direction, and the reflecting surface 21 has a pair of length measuring beams LB1Ya, LB1Yb of the third length measuring axis of the interferometer system 24 and length measuring of the fourth length measuring axis. Each of the beams LB2Y is projected vertically. Of these, the length measurement beams LB1Ya and LB1Yb are projected at the same Z-direction height position of the reflection surface 21 and at a distance of L / 2 from the Y axis passing through the optical axis of the projection optical system PL, respectively, and the length measurement beams LB2Y Are the measurement beams LB1Ya, L
The light is projected at a position on the Y-axis passing through the optical axis of the projection optical system at a distance d below the projection position of B1Yb. Here, the measurement beams LB1Xa, LB1Xb and LB1Ya, LB1
Yb is on the same XY plane. In addition, measuring beam LB
2X and LB2Y are on the same XY plane, and are orthogonal to each other at the center of the optical axis of the projection optical system PL.

The reflecting surfaces 22 and 21 for the six measurement beams
The X- and Y-direction positions of the reflection surfaces 22 and 21 at the projection positions of the respective beams are measured by the interferometer system 24 based on the reflected beams from the laser beam, and the measurement information from the interferometer system 24 is sent to the main control system 34. In the main control system 34 as a control means, the leveling stage 18 is normally used.
The X coordinate, the Y coordinate, the θ rotation (yaw), the pitching (rotation around the Y axis), and the rolling (rotation around the X axis) are calculated as follows.

That is, the main control system 34 calculates the X coordinate of the leveling stage 18 based on the average value (X1 + X2) / 2 of the measurement value X1 of the measurement beam LB1Xa and the measurement value X2 of the measurement beam LB1Xb. The Y coordinate of the leveling stage 18 is calculated from the average value (Y1 + Y2) / 2 of the measurement value Y1 of LB1Ya and the measurement value Y2 of the measurement beam LB1Yb, and ｛(X1-X2) / L + (Y1-Y).
2) The yawing amount is calculated by the calculation of / L｝ / 2.
Further, the main control system 34 uses the measurement value X1 of the measurement beam LB1Xa, the measurement value X2 of the measurement beam LB1Xb, and the measurement value X3 of the measurement beam LB2X, and ｛(X1 + X2).
The pitching amount of the leveling stage 18 is calculated based on / 2−X3｝ / d.

In the main control system 34, the length measurement beam LB
1Y measured value Y1, measured beam LB1Yb measured value Y
2 and the measured value Y3 of the measurement beam LB2Y, the rolling amount of the leveling stage 18 is calculated as ｛(Y1 + Y2).
/ 2−Y3} / d.

The main control system 34, based on the measurement values from the interferometer system 24 as described above, controls the X coordinate, Y coordinate, θ rotation (yaw), pitching (rotation around the Y axis), And rolling (rotation around the X axis) is constantly controlled, and based on these values, the Y stage 14, the X stage 16,
The three-dimensional positioning operation of the wafer W by the leveling stage 18 is controlled. Further, the main control system 34 is configured as shown in FIG.
Is controlled by giving a command to a wafer loader controller (not shown), and also controls the entire apparatus.

Further, the main control system 34 supplies the first measurement axis (the measurement beams LB1Xa and LB1Xb) and the third measurement axis (the measurement beams LB1Ya, LB1Ya, LB1Yb) to the second measuring axis (measuring beam LB2X) and the fourth measuring axis (measuring beam LB2Y)
It also has the function of switching the length measurement axis to.

The main control system 34 includes a projection exposure apparatus 10
A RAM 40 for storing a program, various parameters, and the like necessary for controlling the respective units is also provided.

According to the projection exposure apparatus 10 configured as described above, the main control system 34 manages the position and orientation of the leveling stage 18 as described above based on the measurement values from the laser interferometer system 24. Then, by controlling the driving of the X stage 16, the Y stage 14 and the like via the wafer driving device 32, the stepping operation of the leveling stage 18 for sequentially positioning the shot areas on the wafer W to the exposure position, and the Exposure of the pattern of the reticle R via the projection optical system PL is repeated, and the pattern of the reticle R is sequentially transferred to each shot area on the wafer W. That is, exposure processing of a step-and-repeat method is performed. At the time of the above-described step-and-repeat exposure processing, alignment of the reticle and the wafer, the Z position of the leveling stage 18 based on measurement values of a focus sensor, a leveling sensor, and the like (not shown), and tilt control on the wafer W are performed. Needless to say, the alignment of each shot area to the image plane of the projection optical system PL on the substrate side (alignment plane setting) is performed in the same manner as in a normal stepper.

As described above, when the exposure of the pattern to all the shot areas on the wafer W is completed, the wafer exchange for exchanging the exposed wafer W with the unexposed wafer W is performed. Since the operation at the time of the wafer exchange includes an operation characteristic of the present invention, the wafer exchange operation will be described below with reference to the flowchart of FIG.

This flowchart is started when the exposure of all the shot areas on the wafer W is completed.

First, in step S200, a stage reset operation for moving (positioning) the leveling stage 18 to a predetermined loading position (wafer replacement position) is performed. In the position control of the leveling stage 18 at this time, the above-described normal position control is performed.

That is, the main control system 34 controls the follow-up control of the leveling stage 18 (ie, the wafer W) with respect to the target value in the translation direction, and measures the measurement value X1 of the length measurement beam LB1Xa of the interferometer system 24 in the X direction. Average value of measured value X2 of long beam LB1Xb (X1 + X2) / 2
And in the Y direction, the length measurement beam LB1
Measurement value Y1 of Ya and measurement value Y2 of measurement beam LB1Yb
Is performed based on the average value (Y1 + Y2) / 2. The main control system 24 controls the yawing of the leveling stage 18 by {(X1-X2) / L + (Y1-Y2) / L}.
/ 2.

When such follow-up control is performed and the leveling stage 18 is positioned at the loading position, the leveling stage is lowered (-) for wafer exchange.
Just before this, the main control system 34 stops the yaw measurement that has been performed up to this point, and controls the translation of the leveling stage 18 in the translation direction. From the normal control based on the measured values (X1, X2) and the measured values (Y1, Y2) of the third measuring axis, the measured value X3 of the second measuring axis and the measured value Y3 of the fourth measuring axis are used. The control is switched to the previous control, that is, the length measurement axis is switched (step S202). At this time, in order to avoid abrupt stage movement as much as possible, it is desirable that the values of X3 and Y3 immediately before switching are stored in the RAM 40, and positioning control is performed using the values as target values. Further, in order to correct an error with the coordinate system before switching the control method, X3 and (X1 + X2) / 2, and Y3 and (Y1 + Y
The correlation with 2) / 2 may be stored in the RAM 40.

Thereafter, the main control system 34 drives the leveling stage 18 downward through the drive device 32 and the drive systems 52a, 52b, 52c. Thereby, the leveling stage 18 is lowered by a predetermined amount (step S204). Due to the lowering of the leveling stage 18, the measuring beams LB1Xa, LB1Xb and LB2X
4 (see the leveling stage 18 shown by a solid line in FIG. 3) in which the three measurement beams have hit (see FIG. 3), the state in FIG. 5 in which only the measurement beam LB2X hits the reflecting surface 22 (see FIG. 3). (See the leveling stage 18 indicated by a virtual line in the middle.) Similarly, the other reflection surface 21 also measures the length measurement beam LB1YaLB1Y with respect to the reflection surface 21.
From the state where the three measurement beams b and LB2Y have hit (see the leveling stage 18 shown by the solid line in FIG. 3), the state where only the measurement beam LB2Y hits the reflecting surface 21 (virtual in FIG. 3). Leveling stage 18 indicated by line
See).

As described above, in the present embodiment, when the leveling stage 18 is lowered from the solid line position to the virtual line position in FIG. However, since the lower one measuring beam remains on the reflecting surfaces 22 and 21 without being cut off, the measurement and control of the XY position of the leveling stage 18 can be continuously performed, and the leveling stage (wafer stage) The inconvenience of the prior art in which the length measurement beam of the laser interferometer that measures the stage position due to the lowering of the stage deviates from the movable mirror and the position cannot be controlled can be solved.

Here, in the state where the leveling stage 18 has been lowered to the imaginary line position in FIG. 3 in the step S204, as shown in FIG. 5, there is a gap between the back surface of the wafer W and the upper surface of the leveling stage 18. Clearance sufficient for the wafer loader arm 38 to enter is ensured. In the case of the present embodiment, the center up 54 is driven to move upward while the leveling stage 18 is descending, and it is intended to secure a sufficient clearance for the wafer loader arm 38 to enter in a shorter time.

Next, a wafer exchange process is performed (step S206). Specifically, in the state of FIG. 5, the wafer loader arm 38 enters below the wafer W and the center up 54 descends by a predetermined amount, similarly to the arm 102 of the conventional example of FIG. Is transferred to the wafer W. With the center up 54 lowered further,
The wafer loader arm 38 holds the exposed wafer and retreats from the leveling stage 18, and another wafer loader arm 38 holding a new unexposed wafer W conveys the wafer W above the center up 54. At this time, it is necessary to control the relative positional relationship between the wafer loader arm 38 and the leveling stage 18 within a certain accuracy range.
(XY translation control) is required.

When the center up 54 rises by a predetermined amount and lifts the wafer from below, the wafer loader arm 38 retreats from above the leveling stage 18, whereby the wafer exchange processing ends.

During the above-described wafer exchange processing, the center-up 54 is controlled by the main control system 34 via a center-up drive mechanism 56.
8 is controlled by a wafer loader control system (not shown) in response to a command from the main control system 54.

After the series of wafer exchange processing is completed, the main control system 34 sets the leveling stage 18
Drive up. Thereby, the leveling stage 18
Rises from the virtual line position to the solid line position in FIG.
Is placed on the upper surface of the leveling stage 18 and
The first measuring axis (measuring beams LB1Xa, LB1Xb) and the third measuring axis (measuring beams LB1Ya, LB1Yb) of the interferometer system 24, which have been deviated until now, are projected on the reflecting surfaces 22, 21. (Step S208).

For this reason, the measurement beam L of the interferometer system
After once resetting the measurement values X1, X2, Y1, and Y2 of B1Xa, LB1Xb, LB2Ya, and LB2Yb (step S210), the measurement value of (X3, Y3) immediately before is reset to (X
1, X2, Y1, Y2), the control method is switched (switching of the measurement axis) according to the reverse procedure of the control method switching performed in step S202 described above (step S212).

Thereafter, the position control of the leveling stage 18 is performed by the above-described normal control method.

As described above, according to the stage device 11 constituting the projection exposure apparatus 10 of the present embodiment, the X stage 16, the Y stage 14, and the substrate stage that moves integrally in the XY plane with these stages are used. The leveling stage 18 can be moved in a direction perpendicular to the moving surface (stage moving surface) of the leveling stage 18, that is, in the optical axis AX direction of the projection optical system PL, and the position of the leveling stage 18 is changed. The measurement beam of the first measurement axis and the measurement beam of the second measurement axis of the interferometer system 24 to be controlled are projected at different positions on the reflecting surface 22 in the optical axis AX direction, and the third measurement axis is measured. The length measuring beam and the length measuring beam on the fourth length measuring axis are projected to different positions on the reflecting surface 21 in the optical axis AX direction. For this reason, even if the leveling stage 18 is moved to one side (downward) in the optical axis direction, a part of the length measurement beams (LB2X, LB2Y) remains on the reflection surfaces 22 and 21. In the present embodiment, the leveling stage 18
Is moved to one side in the optical axis direction and a part of the length measurement beam (LB1) is moved.
If it is known that Xa, LB1Xb, LB2Ya, LB2Yb) deviate from the reflection surfaces 22, 21, the operation of switching the length measurement axis of the interferometer system is performed in advance. For this reason, even if the leveling stage 18 is lowered in order to secure the space for the wafer loader arm 38 to enter when the wafer is replaced, the leveling stage 1 can be moved without any inconvenience.
8 can be continued, whereby the wafer exchange can be properly performed while controlling the position immediately below the projection optical system PL. Therefore, according to the projection exposure apparatus 10 of the present embodiment, a high N.D.
A. Therefore, even if the working distance between the projection optical system PL and the wafer surface is reduced, the leveling stage 18 can be properly replaced on the spot without retreating from below the projection optical system PL in the horizontal direction. Therefore, the throughput of wafer exchange can be improved, and the size and footprint of the stage device 11 including the substrate stage (leveling stage) can be reduced.

The length measuring axis used after the switching of the length measuring axis of the interferometer system is the length measuring axis normally used for pitching and rolling measurement. Is used for position measurement in a state where it is lowered in the Z-axis direction. Therefore, the attitude of the leveling stage 18, particularly θx (rotation around the X axis), θ
Measurement about y (rotation around the Y axis) becomes possible, and control and the like by comparison with a focus sensor measurement value (not shown) become possible.

In the above-described embodiment, the substrate stage is constituted by the leveling stage 18 and the leveling stage 18 is moved up and down. However, the present invention is not limited to this, and the X level of the lower layer is not limited to this. The stage, the Y stage and the like may be configured to be able to move up and down,
In short, it is only necessary that the mounting surface of the wafer as the substrate can be moved up and down. In the above embodiment, the leveling stage 18
The case where the side surfaces are the reflecting surfaces 22 and 21 has been described, but the present invention is not limited to this, and the present invention can be suitably applied even when a moving mirror is provided on the substrate stage.

In the above embodiment, the case where the present invention is applied to the stage device provided with the leveling stage as the substrate stage moving in the two-dimensional direction has been described. However, at least the substrate stage moving in the one-dimensional direction is described. The present invention can be suitably applied to any stage device provided with.

In the above embodiment, the case where the first and third measuring axes of the interferometer system 24 are each composed of two measuring beams has been described. Needless to say, the arrangement is not limited to the above embodiment.

Further, in the above embodiment, the case where the present invention is applied to a step-and-repeat type projection exposure apparatus has been described. However, the present invention is not limited to this, and the present invention is also suitable for a scan type projection exposure apparatus. It can be applied to

[0065]

As described above, according to the first aspect of the present invention, the effect that the moving stroke of the substrate mounting surface on the substrate stage in the direction orthogonal to the stage moving surface can be increased. is there.

According to the second aspect of the present invention, in addition to the above effects, there is an effect that the substrate can be easily replaced.

According to the third aspect of the present invention, in addition to the effects of the above-mentioned inventions, there is an effect that the position of the substrate stage in two-dimensional directions and pitching and rolling can be normally managed.

According to the fourth aspect of the present invention, even when the working distance between the projection optical system and the photosensitive substrate is narrow, it is possible to sufficiently secure a space necessary for exchanging the sensitive substrate. It is possible to provide an unprecedented and excellent projection exposure apparatus capable of preventing the reflection surface on the stage and the stage from being enlarged.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of a projection exposure apparatus according to one embodiment.

FIG. 2 is a schematic sectional view showing an internal configuration of an X stage of FIG.

FIG. 3 is a schematic perspective view showing the arrangement of a measurement beam of the interferometer system of FIG. 1 in the vicinity of a leveling stage.

FIG. 4 is a diagram showing a state viewed along the X-axis direction when the leveling stage is at a position indicated by a solid line in FIG. 3;

FIG. 5 is a diagram showing a state viewed along the X-axis direction when the leveling stage has been lowered to a position indicated by a dotted line in FIG. 3;

FIG. 6 is a flowchart showing a flow of a wafer exchange process of the projection exposure apparatus of FIG. 1;

FIG. 7 is a diagram for explaining an example of a disadvantage of a conventional example.

FIG. 8 is an explanatory diagram showing a conventional example.

FIG. 9 is an explanatory diagram showing another conventional example.

FIG. 10 is a diagram for explaining one problem to be solved by the invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Projection exposure apparatus 11 Stage apparatus 18 Leveling stage (substrate stage) 21, 22 Reflection surface 24 Interferometer system 34 Main control system (control means) 38 Transfer arm (transfer system) 54 Center up (substrate transfer mechanism) W Wafer (substrate) LB1Xa, LB1Xb Measurement beam on first measurement axis LB2X Measurement beam on second measurement axis LB1Ya, LB1Yb Measurement beam on third measurement axis LB2Y Measurement beam on fourth measurement axis R Reticle (Mask) PL Projection optical system

Claims (4)

[Claims] 1. A substrate stage on which a substrate is placed and movable in at least one direction within a predetermined reference plane; and a first stage for measuring a position of the substrate stage via a reflection surface provided on the substrate stage. An interferometer system comprising: a length measurement axis; and a second length measurement axis projected from a projection position of the first length measurement axis on the reflection surface to one side in a first axis direction orthogonal to the reference plane; While managing the position of the substrate stage based on the measurement value of the first length measurement axis of the interferometer system, when the mounting surface of the substrate moves to one side of the first axis direction by a predetermined amount or more Controlling the position of the substrate stage based on the measurement value of the second measurement axis by switching the measurement axis of the interferometer system. 2. A transfer mechanism for holding a substrate and moving relative to the substrate stage in the first axial direction when transferring the substrate to and from a transfer system for transferring the substrate. The stage device according to claim 1, further comprising: 3. The substrate stage is movable in two orthogonal directions within the reference plane, and the interferometer system performs a third measurement orthogonal to the first measurement axis and the second measurement axis, respectively. A control unit for controlling a position of the substrate stage in a two-dimensional direction based on measured values of the first and third measurement axes; And controlling the pitching of the substrate stage based on the measurement values of the second measurement axis, and managing the rolling of the substrate stage based on the measurement values of the third and fourth measurement axes. Item 3. The stage device according to item 1 or 2. 4. A projection exposure apparatus for projecting and exposing a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein the stage apparatus according to any one of claims 1 to 3, A projection exposure apparatus provided for positioning the sensitive substrate.