JPH09312255A - Exposure equipment - Google Patents

Abstract

(57) [Abstract] An object of the present invention is to suppress the tilt and swing of the entire apparatus and to improve the synchronization performance between the mask stage and the substrate stage. A mask stage 16 and a substrate stage 14
And are levitationally supported on the base member 12, both stages 16 and 14 are driven by the linear motor 13 in opposite directions in the scanning direction in a non-contact manner. The momentum is preserved without applying any force to the base member 12 or the like.
Here, since the mass ratio of the stage 16 and the stage 14 is set to be the same as the reduction ratio of the projection optical system (not shown),
According to the law of conservation of momentum, stage 16 and stage 14
The speed ratio is the reciprocal of the reduction ratio of the projection optical system, and the two stages 16 and 14 are accurately controlled in synchronization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, and more specifically, to a pattern (semiconductor circuit pattern or pattern formed on a mask while synchronously scanning a mask stage holding a mask and a substrate stage holding a photosensitive substrate. The present invention relates to an exposure device that transfers a liquid crystal circuit pattern) onto a photosensitive substrate via a projection optical system.

[0002]

2. Description of the Related Art In recent years, a step-and-scan type (hereinafter referred to as "S & S method") scanning type exposure apparatus for realizing a resolution line width of 0.5 .mu.m or less has been developed as an exposure apparatus for manufacturing semiconductor elements. , Are actively being improved for full-scale practical use in semiconductor manufacturing lines. Such an S & S type exposure apparatus is disclosed in, for example, Japanese Patent Laid-Open No. Sho 56-56.
-111218 Publication, SPIE Vol.1088 Optical / Lase
r Microlithography II (1989), pages 424-433.
Page, JP-A-2-229423, JP-A-4-4-2
No. 77612, and the like.

Among them, in the above publication, the mask is moved one-dimensionally in the scanning direction at the time of scanning exposure in order to use the mirror projection of the same size in the S & S system, and the semiconductor wafer is scanned and moved in the scanning direction. It is disclosed that the structure is configured to be step-moved in a direction orthogonal to it. Further, in the above-mentioned document, a 1/4 reduction projection optical system having an arcuate slit field of view in which an optical lens and a reflecting mirror are combined is used, and the speed ratio between the mask (or reticle) and the wafer is measured during scanning exposure. Precisely controlled 4: 1 S &
An S-type reduction projection scanning type exposure apparatus is disclosed. Further, in the above publication, an excimer laser is used as illumination light, and an S & S type exposure is performed by limiting a regular hexagon inscribed in a circular image field of a general reduction projection lens system to an effective projection area. In the above publication, the S & S exposure is performed by limiting the linear slit (rectangular) shaped area along the diameter in the circular image field of the ordinary reduction projection lens system to the effective projection area. A device is disclosed.

In addition, Japanese Laid-Open Patent Publication No. 6-300973 discloses an ArF excimer having a wavelength of 200 nm or less as exposure illumination light, which is composed of a plurality of optical lenses, a beam splitter, and a concave mirror in order to obtain higher resolution. A reduction projection optical system applied to a laser is disclosed. A projection optical system similar to that is disclosed in Japanese Patent Application No.
It is also disclosed in Japanese Patent No. 88087.

[0005]

In each of the above-mentioned prior arts, in the scanning type exposure apparatus using the reduction projection optical system,
Generally, the reticle stage holding the reticle and the wafer stage holding the wafer are configured to scan and move at a speed ratio that matches the reciprocal of the reduction magnification of the projection optical system. For this reason, a drive source for the reticle stage (for example, a linear motor) and a drive source for the wafer stage (for example, a linear motor) are separately provided in the apparatus body (column for fixing the projection optical system), and the reticle and the wafer are separated from each other. It was necessary to precisely control both drive sources so that they were moved relative to each other while maintaining a constant speed ratio. That is, a linear motor that linearly moves the reticle stage relative to the projection optical system during scanning exposure, a linear motor that linearly moves the wafer stage relative to the projection optical system, and the moving position of each stage relative to the projection optical system are individually specified. A servo control circuit for individually precisely controlling each linear motor based on the measured value of the laser interferometer is required.

Further, in the case of a scanning type exposure apparatus using such a reduction projection optical system, the reticle stage (mask stage) and the wafer stage (substrate stage) have different dynamic characteristics. A method of scanning by following the stage with the poorer characteristics is generally adopted. However, the stage with inferior characteristics is slow in settling due to the influence of body shake, which is the framework of the device, and in order to improve the synchronization performance, a stage with excellent dynamic characteristics is required as the stage with better characteristics. Not only that, but also a special device such as so-called active vibration isolator (vibration isolator) for reducing body sway is indispensable, which complicates the device configuration and increases cost. was there.

Further, in the scanning exposure apparatus using the reduction projection system in which the optical axis from the reticle to the wafer is linear, like the apparatus described in the above-mentioned publication, a reticle stage is generally used. The wafer stage and the wafer stage are arranged so as to move in the horizontal direction, and 80 to 15 in the vertical direction.
Since the reticle stage is configured to be separated by about 0 cm, the reticle stage is arranged above the exposure apparatus body, and the entire apparatus tilts due to the scan movement of the reticle stage during scanning exposure, and each structure forming the apparatus body. There was also the inconvenience of saying that excessive stress was applied to things (columns, surface plates, etc.).

In addition, if a synchronism occurs in the synchronous control of the linear motor for the reticle stage and the linear motor for the wafer stage, or if a measurement error (count error) occurs in the interferometer, it is transferred to the shot area on the wafer. There is also a disadvantage that the transferred pattern image has a non-uniform transfer magnification in the scanning direction.

The present invention has been made in view of the inconveniences of the prior art, and its object is to provide a simple structure.
It is an object of the present invention to provide an exposure apparatus which can reduce the stress generated in a structure forming the apparatus, suppress the inclination and swing of the entire apparatus, and improve the synchronization performance between the mask stage and the substrate stage.

[0010]

According to a first aspect of the present invention, a pattern formed on the mask is projected while a mask stage holding a mask and a substrate stage holding a photosensitive substrate are synchronously scanned. And a substrate stage that is floated and supported on a base member via an air bearing; and a mass that is a reduction magnification of the projection optical system times the mass of the substrate stage. A mask stage that is floated and supported on the base member via an air bearing; and a first linear motor that is provided between the two stages and that drives the two stages in opposite directions along the scanning direction. Have.

According to this, since the mask stage and the substrate stage are floated and supported on the base member, both stages are driven by the first linear motor in opposite directions along the scanning direction without contact, At this time, the movement of both stages does not exert any force on the base member and the like, and the momentum is preserved. Since the mass of the mask stage is the reduction magnification of the mass of the substrate stage times that of the projection optical system, the speed ratio between the mask stage and the substrate stage is the reciprocal of the reduction ratio of the projection optical system according to the law of conservation of momentum. Therefore, both stages are accurately controlled in synchronization. Further, since the center of gravity of the entire system hardly changes, the body main body including the base member does not sway or tilt due to the scanning of both stages.

According to a second aspect of the present invention, in the exposure apparatus according to the first aspect, the projection optical system is an optical system for projecting an inverted image of the pattern formed on the mask on the photosensitive substrate. It is characterized by According to this, even if the mask pattern has an asymmetrical shape, when the mask stage and the substrate stage are synchronously scanned in opposite directions by the first linear motor, an image of the pattern is formed on the photosensitive substrate. Is accurately projected and exposed.

The invention described in claim 3 is the invention according to claim 1 or 2.
In the exposure apparatus described in (1), the photosensitive substrate is held horizontally on a substrate stage, the mask is held vertically on the mask stage, and the projection optical system includes a plurality of transmissive optical elements and a light splitter. And a reflective optical element, which is an optical system for projecting the pattern of the mask arranged on the object plane onto the photosensitive substrate arranged on the image plane at a predetermined reduction magnification.

According to this, for example, the half TT according to claim 4 is provided on the side opposite to the mask stage via an optical splitter.
It becomes possible to dispose the L alignment detection system, and in this case, the alignment mark formed on the mask by the half TTL alignment detection system via the optical splitter and the alignment mark on the photosensitive substrate are separated. Can be detected simultaneously or simultaneously, and the detection of the reticle alignment mark and the detection of the wafer alignment mark can be combined by a single detection system.

According to a fifth aspect of the present invention, in the exposure apparatus according to any one of the first to third aspects, the mask stage is provided between the base member and the mask stage in the scanning direction. It is characterized in that a second linear motor that is driven by a motor is provided. According to this,
By driving the second linear motor with the first linear motor turned off, the mask stage can be independently driven with respect to the base member in the scanning direction. It is possible to reset and fine-tune.

The invention according to claim 6 is the invention according to claim 3 or 5.
In the exposure apparatus described in (3), a third linear motor that drives the substrate stage along the scanning direction is provided between the base member and the substrate stage. According to this, by driving the third linear motor with the first linear motor (and the second linear motor) turned off, the substrate stage is independently driven with respect to the base member in the scanning direction. This makes it possible to reset or finely adjust the position of the substrate stage.

The invention according to claim 7 is the invention according to claim 5 or 6.
In the exposure apparatus described in (1), a regenerative braking control circuit that finely adjusts a speed ratio of the first linear motor during scanning of the both stages is provided together with at least one of the second linear motor and the third linear motor. It is characterized by According to this configuration, the regenerative braking control circuit causes at least one of the second linear motor and the third linear motor to perform the regenerative braking action, so that the mask stage scanned in the opposite directions by the first linear motor and the mask stage It is possible to increase the apparent mass of at least one of the substrate stages and finely adjust the speed ratio during scanning of both stages. Here, the regenerative braking means that the motor functions as a kind of generator to generate a braking action, thereby increasing the load driven by the first linear motor (that is, the mask stage and the substrate). The apparent mass of at least one of the stages can be increased).

According to the seventh aspect of the present invention, when the mass ratio of both stages is not accurately set to a desired value, the speed ratio of both stages is adjusted to ensure the desired synchronization performance. In addition to consciously slightly shifting the mass ratio of both stages from the desired value and adjusting the regenerative braking amount appropriately during scanning, the speed ratio of both stages is always adjusted to the reduction ratio of the projection optical system. By matching the reciprocal number, stable synchronization performance can be secured even when the momentum is not completely preserved.

According to the invention of claim 8, claim 1
8. The exposure apparatus according to any one of claims 1 to 7, wherein the substrate stage is a first stage driven in the scanning direction by the first linear motor, and the first stage holds the photosensitive substrate and is integrated with the first stage. And a second stage which is movable in the direction orthogonal to the scanning direction while being guided by the first stage. According to this, the second stage holding the substrate is moved in the scanning direction integrally with the first stage to perform scanning exposure, and then the second stage is moved in a direction orthogonal to the scanning direction with respect to the first stage. By repeating the movement, so-called step-and-scan type exposure can be easily realized.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The principle configuration of the present invention is shown in FIG.
It will be described based on. FIG. 1 shows the basic configuration of an exposure apparatus 10 according to the present invention. This exposure apparatus 10
Is a vibration isolation table 12 as a base member, and the vibration isolation table 12
A substrate stage 14 which is levitationally supported on an upper surface via an air bearing (air bearing) 13, and this substrate stage 14
The mask stage 16 is floated and supported above. A linear motor 18 is provided between the substrate stage 14 and the mask stage 16. That is, for example, the drive coil 18A of the linear motor 18 is provided on the mask stage 16 side of the mass Mr, and the mass Mw
A magnet track portion 18B of the linear motor 18 is provided on the substrate stage 14 side of the. Further, the mass Mr of the mask stage 16 and the mass Mw of the substrate stage 14
Is a reduction magnification of the projection optical system (not shown).

According to the exposure apparatus 10 of the present invention thus constructed, since both stages 14 and 16 are supported by levitation, when the linear motor 18 is excited, only the internal force acts and the magnitude is large. Acting force F1 and reaction force F2 (F2 = -F1) having the same magnitude but opposite directions are applied to the respective stages 16 and 14. Given that the moving speeds of both stages 16 and 14 caused by this force are Vr and Vw, if air resistance and the like are ignored, the law of conservation of momentum holds that Mr.Vr = Mw.Vw. Therefore, the speed ratio of both stages 16 and 14 is Vr / Vw = Mw / Mr. However, in the case of the present invention, both stages 16 and 1
Since the mass ratio Mr / Mw of 4 is set equal to the reduction magnification Mp1 of the projection optical system (not shown) as described above, Vr / Vw = Mw / Mr = 1 / Mp1 and both stages 16, The speed ratio of 14 matches the reciprocal of the reduction ratio of the projection optical system. Therefore, ideally, when a system in which the momentum is preserved is configured, if the speed (or position) of only one of the substrate stage 14 and the mask stage 16 is servo-controlled, both stages 14 and
16 can be reliably scanned synchronously.

For example, when servo is performed on the mask stage 16, even if the mask stage 16 moves oscillatingly, the substrate stage 14 is similar to the mask stage 16 at the same speed ratio as the reciprocal of the mass ratio. It vibrates. Further, since the momentum is stored, the center of gravity of the system is always constant, so that the vibration isolation table 12 does not rock. Therefore, the synchronization error during scanning of both stages 16 and 14 is always zero.

[0023]

【Example】

<< First Embodiment >> A first embodiment of the present invention will be described below with reference to FIGS. 2 to 3 show the configuration of the main part of the step-and-scan exposure apparatus 100 according to the first embodiment.

The exposure apparatus 100 includes a base structure 200 as a base member which is horizontally held on a vibration isolation pad (not shown), and a wafer stage 14 as a substrate stage which is floated and supported on the base structure 200. Also, a reticle stage body 206 as a mask stage, a projection optical type PL held by a main body column (not shown) above the wafer stage 14 and fixed to the base structure 200, and a base structure similarly held by a main body column (not shown). The illumination optical system 212 fixed to the body 200 is provided. here,
The wafer stage 14 is a first wafer stage body 2 as a first stage that is movable in the X direction (scanning direction).
08, and X is guided by the first wafer stage body 208.
The second wafer stage body 220 is a second stage movable in the Y direction orthogonal to the direction.
The specific configuration will be described later in detail.

On the upper surface of the base structure 200, two prisms extending parallel to each other in the X direction (direction orthogonal to the paper surface) orthogonal to the Y direction on one end (left end) side in the Y direction in FIG. Fixed guide rails 202 and 204 of
The other upper surface of the base structure 200 is flatly polished in order to support the moving bodies (stages) in the Z direction and move them smoothly in the XY plane. On one of the fixed guide rails 202, a guide surface 202A that defines a reticle stage body 206 that is movable in the X direction in the Z direction and a Y surface are provided.
The guide surface 202B that defines the direction is formed, and the other fixed guide rail 204 has a first movable surface in the X direction.
Guide surface 2 for defining the wafer stage body 208 in the Y direction
04A is formed.

The reticle stage body 206 is shown in FIG.
As shown in FIG. 5, a vertical type that holds the reticle R as a mask vertically is used, and this reticle stage body 206 holds the reticle R vertically and is perpendicular to the optical axis AX of the projection optical system PL. There is provided a reticle fine movement stage 210 for performing fine movement in translation and fine movement in rotation within a plane (XZ plane in the drawing).

The illumination optical system 212 is arranged on the opposite side of the projection optical system PL with respect to the reticle R, and the rectangular pattern area of the reticle R is scanned in the scanning direction (X direction).
Irradiation light having an intensity distribution that extends in a slit shape (or a rectangular shape) in a direction orthogonal to is irradiated. The pattern portion of the reticle R illuminated with the linear slit-shaped illumination light is located at the center of the circular visual field on the object plane side perpendicular to the horizontal optical axis AX of the projection optical system PL, and serves as the first transmission optical element. 1 lens group G
A predetermined reduction magnification Mp1 (1/4 in this embodiment) which is telecentric on both sides by the first, second lens group G2, third lens group G3, beam splitter BS as a light splitter, and concave mirror MR as a reflection optical element. Through the projection optical system PL of (3). Here, as the projection optical system, an inverted image (inverted on the X axis) of a circuit pattern (not shown) formed on the pattern surface of the reticle R is used as the wafer W.
What is projected above is used. The detailed configuration of such a projection optical system PL is described in the above-mentioned JP-A-5-88.
No. 087 is disclosed in detail in Japanese Unexamined Patent Publication No. 6-300973, etc., and therefore further description is omitted here.

At the bottom of the reticle stage body 206, a pad PDA for an air bearing (air bearing) that faces the guide surface 202A of the fixed guide rail 202 and supports the weight of the reticle stage body 206, and the fixed guide rail 202. Of the reticle stage body 206 facing the guide surface 202B of the air bearing pad PDB for the air bearing, and the fixed guide rails 202 and 2
An air bearing pad PDC for supporting the weight of the reticle stage body 206 is fixed so as to face the surface 200A of the base structure 200 between the pad structure 04 and the base structure 04. Of these pads, the pad PDB for restraining displacement in the Y direction is a plurality of air pads that eject pressurized air and a plurality of vacuum pads that are alternately arranged in the X direction (direction orthogonal to the paper surface) to suck air. It is composed of a pneumatic / vacuum combination type pad (vacuum preload type air bearing) which is a combination of parts. According to this pneumatic / vacuum combination type pad, the reticle stage body 206 separates a predetermined clearance from the guide surface by the balance between the suction force (preload) of the vacuum pad portion and the pressure of the air blown from the air pad portion. Suspended and supported. In addition, pad PDA, pad P
In the case of DC, the own weight of the reticle stage body 206 acts as a preload, and this own weight and the pad PDA, the pad PD
The reticle stage body 206 is levitationally supported by a predetermined clearance from the guide surface in balance with the pressure of the air blown out from C. Also in the following description, the pad supports its own weight in this sense.

The wafer stage 14 consisting of a first wafer stage body 208 and a second wafer stage body 220 is levitationally supported on the upper surface of the base structure 200 at the other end of the fixed guide rail 204 in the Y direction.

The first wafer stage body 208 is formed on a rectangular frame spread on the XY plane on the base structure 200 (see FIG. 3), and its own weight faces the upper surface of the base structure 200 at four corners. It is supported by pads PDD and PDE for air bearings arranged. Then, the displacement of the first wafer stage body 208 in the Y direction (the horizontal direction in the paper surface) is caused by the vertical guide surface 204A of the fixed guide rail 204.
Is constrained by a pneumatic / vacuum combination type pad PDF fixed to the first wafer stage body 208 so as to face. As a result, the first wafer stage body 208 is guided by the guide surface 204A and the surface of the base structure 200 and is movable in the X direction without friction.

Then, the first wafer stage body 208
A first linear motor 216 arranged along the X direction is provided between the reticle stage body 206 and the reticle stage body 206.
The first linear motor 216 is fixed to the first wafer stage body 208 side and extends over a moving stroke in the X direction. A magnet track portion 216A (the magnet track portion 216A has a cross-sectional shape extending in the X axis direction). ), A reticle stage body 206, and a pair of magnets fixed to the upper and lower surfaces of the yoke.
And a drive coil portion 216B fixed to the side,
Generates directional thrust. That is, in the first embodiment,
By driving the linear motor 216, for example,
The reticle stage unit 2 is integrated with the drive coil unit 216B.
When 06 is driven to the front side of the paper, the reaction causes the wafer stage 14 to be driven to the back side of the paper integrally with the magnet / track portion 216A.

Further, the reticle stage body 206 is
The second linear motor 214 provided along the X direction can independently move in the X direction. The linear motor 214 is fixed to the base structure 200 side, and the magnet track portion 214A extends over the movement stroke of the reticle stage body 206 in the X direction (the magnet track portion 214A is a cross section fixed on the guide surface 200A). It is composed of a U-shaped yoke and a pair of magnets fixed to the left and right inner surfaces of the yoke) and a drive coil portion 214B fixed to the reticle stage body 206 side, and produces thrust in the X direction. The second linear motor 214 is used to return the reticle stage body 206 to a predetermined reset position and has various roles, which will be described later.

Further, the first wafer stage body 208
As shown in FIGS. 2 and 3, a second wafer stage body 220, on which a wafer holder 218 for vacuum-sucking the wafer W and a fiducial mark plate FM are mounted, is mounted inside the frame of the second wafer stage body 220.
Are held so as to be movable in the Y direction. Note that FIG. 3 shows the configuration of the wafer stage body as seen on the XY plane. In the lower part of the second wafer stage body 220, as shown in FIG. 2, a plurality of pads PD for air bearings are provided to face the upper surface of the base structure 200 and to support its own weight.
I and PDG are attached.

As shown in FIG. 3, the inner surface of either one of the two linear frame portions of the first wafer stage body 208 extending in the Y direction with the second wafer stage body 220 sandwiched therebetween, as shown in FIG. A guide surface 22 for guiding in the Y direction (constraining the displacement in the X direction) with the second wafer stage body 220.
2 is formed, and a pair of pneumatic / vacuum combination type pads PDH facing the guide surface 222 are fixed to one end of the second wafer stage body 220.

Further, Y of the first wafer stage body 208
Between each of the two linear frame portions extending in the direction and the second wafer stage body 220, the second wafer stage body 220 is provided with the second wafer stage body 220 as shown in FIG.
A pair of linear motors 24 for moving in the Y direction with respect to
0, 242 are provided. The pair of linear motors 24
0, 242 drive coil portions 240A, 242A are the second
Since it is fixed on both sides of the wafer stage body 220, the second wafer stage body 220 is slightly rotated (second order) on the surface of the base structure 200 by subtly changing the driving amount of each linear motor 240, 242. You can

Now, with reference to FIG. 3, a description will be further given of the inverse value configuration of the reticle R and the first and second wafer stage bodies 208 and 220 on the XY plane. In FIG. 3, X
The movement position of the reticle R in the X direction (scanning direction) in the Z plane and the minute rotation amount (yawing error) of the reticle R in the XZ plane are part of the fine movement stage 210 provided in the reticle stage body 206. A laser beam for length measurement is projected onto the fixed reflecting mirror CMx, and the laser beams are sequentially measured by laser interferometers RIFx and RIFθ that receive the reflected beam. Also, although not shown in any of FIGS.
There is also provided a laser interferometer RIFy that sequentially measures the position of the reticle fine movement stage 210 in the Z direction (the vertical direction in the paper surface in FIG. 2, the direction orthogonal to the paper surface in FIG. 3). Here, the laser interferometer RIFy measures the position of the reticle fine movement stage 210 in the Z direction.
Considering the wafer stage coordinate system, this Z-direction position corresponds to the Y-direction position.
The symbol Fy is used. Therefore, in the following description, the measurement value of the laser interferometer RIFy is expressed as PY.

The coordinate position of the wafer W in the XY plane is measured by the movable mirror My extending in the X-axis direction at the other end (right end) in the Y-direction on the second wafer stage body 220. A laser interferometer WIFy, which projects a laser beam and receives the reflected beam, and a laser beam for measuring length, are transmitted to a movable mirror Mx extending in the Y-axis direction at one end of the second wafer stage body 220 in the X-direction. It is sequentially measured by a laser interferometer WIFx that projects and reflects the reflected beam. Each of the interferometers WIFx and WIFy simultaneously operates the second wafer stage body 2
The minute rotation amount of 20 (yawing error) is also sequentially measured. The moving mirror and the interferometer are not shown in FIG.

Each of the above interferometers RIFx, RIFθ, RI
Fy, WIFx, and WIFy are all the base structure 2
A reference plane mirror and a corner prism (neither shown) are fixed to the base structure 200 so that the coordinate positions of the reticle R and the wafer W are measured with reference to 00.

Although one shot area SA is shown on the wafer W in FIG. 3, in the state of FIG. 3, the center point of the shot area SA is the vertical optical axis A of the projection optical system PL.
X (the optical axis of the lens group G3 in FIG. 2), the center point of the pattern area of the reticle R is also the horizontal optical axis AX (the optical axis of the lens groups G1 and G2 in FIG. 2). )
Matches exactly.

In addition, in the exposure apparatus 100 of the first embodiment, on the wafer W or the fiducial mark plate FM from between the projection optical system PL and the reticle R via the peripheral part of the projection visual field of the projection optical system PL. Through the beam splitter BS and the third lens group G3, the alignment optical system 230 of the TTL (through the lens) system for photoelectrically detecting the alignment mark formed on the wafer W or the reference mark plate FM. A half-TTL alignment optical system 232 is provided for detecting the upper alignment mark and detecting the alignment mark on the reticle R via the beam splitter BS and the second and first lens groups G2 and G1. There is.

In the above structure, the total mass Mr of both the reticle stage body 206 and the reticle fine movement stage 210 and the wafer stage 14, that is, both the first wafer stage body 208 and the second wafer stage body 220. The ratio to the total mass value Mw is set to be equal to the reduction magnification Mp1 of the projection optical system PL. In this embodiment, as described above, the magnification Mp1 of the projection optical system is 1 /
Since it is 4, the mass ratio Mr / Mw is also set to 1/4. As a specific example, the total mass Mw of the wafer stage body is about 40 to 100 kg, and the total mass Mr of the reticle stage body is about 10 to 25 kg, although it depends largely on the diameter of the wafer W used. can do.

FIG. 4 shows the configuration of the control system of the exposure apparatus 100 according to the first embodiment. This control system
Alignment control system 259, stage main control system 260,
The drive circuit 253, the drive system 254, the main scanning drive system 255, the drive circuit 256, and the like are included. here,
The respective components of the control system will be described together with their actions.

The above-mentioned TTL alignment detection system 230
Detection information from the half TTL alignment detection system 2
The detection information from 32 is input to the alignment control system 259, where the coordinate position and the positional deviation error of the wafer W, the reticle R, or the alignment mark on the fiducial mark plate FM are determined.

The stage main control system 260 is interfaced with a mini computer for operation (not shown), and each of the linear motors 214, 216 and 24 described above is connected.
0, 242, a drive system 254 for controlling the reticle fine movement stage 210, a main scanning drive system 255, a drive circuit 256, and a drive circuit 253, respectively.

Among them, the drive circuit 253 has position information PX, PY, Pθ in the X direction, Y direction, rotation (yaw) direction and main control system 260 measured by interferometers RIFx, RIFθ, RIFy on the reticle side. The reticle fine movement stage 210 is servo-controlled based on the command information from the reticle R, and the reticle R is finely moved during alignment or during scanning exposure.

The drive system 254 drives the second linear motor 214 based on the position information PX (and speed information Vx) measured by the reticle side interferometer RIFx and the command information from the main control system 260. Servo control.

The main scanning drive circuit 255 operates mainly during scanning exposure, and is measured by the velocity information Vx (or position information PX) measured by the reticle side interferometer RIFx and the wafer side interferometer WIFx. Speed information Vx
(Or position information PX), while monitoring either one or both, the absolute speed of at least one of the reticle stage body 206 and the first wafer stage body 208 becomes equal to the speed command information from the main control system 260. First
Servo control of the linear motor 216.

The drive circuit 256 is a wafer side interferometer WI.
Position information PX, P measured by Fx, WIFy
The drive of the pair of linear motors 240 and 242 described above is servo-controlled based on Y and Pθ and command information from the main control system 260.

Next, the first book constructed as described above
The operation of the exposure apparatus 100 of the embodiment during scanning exposure will be described. Here, the half TTL alignment detection system 232
It is assumed that the reticle alignment according to the above, the global alignment between the reticle R and the wafer W by the TTL alignment detection system 230, the baseline measurement using the reference plate FM, and the like have been completed.

First, in the stage main control system 260, the main scanning drive system 254 and the drive circuit are arranged so as to position one end portion of a predetermined shot area on the wafer W in the X-axis direction within the exposure field of the projection optical system PL. Give a command to 256,
The linear motor 216 and the linear motors 240 and 242 are driven. As a result, the second wafer stage body 220
Of the first wafer stage body 208 is moved X in the direction opposite to the reticle stage body 206 integrally with the first wafer stage body 208.
Driven in the Y direction with respect to the wafer stage body 208 of
One end of the shot area in the X-axis direction has a projection optical system PL.
Positioned within the exposure field of the. Next, the stage main control system 260 drives the second linear motor 214 via the drive system 254 to drive the reticle stage body 206.
To the predetermined reset position. As a result, the other end of the reticle in the X-axis direction coincides with the exposure field of the projection optical system PL. In this case, the second linear motor 214 is servo-controlled based on the measurement value of the reticle interferometer 250 so that the position of the reticle stage body 206 does not change in the X direction.
6 to drive the first and second wafer stage bodies 208, 2
20 is moved integrally on the base structure 200 in the X direction, and then only the second linear motor 214 is servo-controlled based on the measurement value of the reticle interferometer 250 to move the reticle stage body 206. Alternatively, the base structure 200 may be independently moved in the X direction.

Next, the stage main control system 260 gives a command to the main scanning drive system 255 to drive the linear motor 216 to start the exposure of the shot area. In the case of the first embodiment, the wafer stage 14 and the reticle stage body 2
Since both 06 are levitationally supported on the base structure 200 via an air bearing (vacuum bearing),
When a drive current is supplied to the drive coil portion 216B of the linear motor 216 of FIG. 1, the first wafer stage body 208 and the second wafer stage body 220 are integrated with each other on the upper surface of the base structure 200 in the + X direction, for example, according to the law of conservation of momentum. The reticle stage body 206 moves at the speed Vw, and moves on the upper surface of the base structure 200 in the −X direction at the speed Vr. In this case, as described above, the reticle stage body 20
Since the ratio of the total mass Mr of both 6 and the reticle fine movement stage 210 to the total mass Mw of the wafer stage 14 is set equal to the reduction ratio 1/4 of the projection optical system PL, the momentum conservation The reticle stage body 2 regardless of acceleration, constant velocity, or deceleration.
The speed ratio of 06 to the wafer stage 14 is 4: 1, that is, the reciprocal of the reduction ratio Mp1. Therefore, by servo-controlling the speed (or position) of only one of the wafer stage 14 and the reticle stage body 206, both can always be reliably and synchronously scanned.

Here, since the absolute values of the scanning velocities Vw and Vr (velocity with respect to the base structure 200) influence the amount of exposure given on the wafer W during scanning exposure, in the main scanning drive system 255, the reticle stage body is used. The interferometer RIFx for position measurement in the X direction 206, or the first wafer stage body 2
While monitoring the speed information output from one of the interferometers WIFx for position measurement in the X direction 08, the first linear motor 21 is controlled so that the speed becomes a designated constant value.
Servo control of the drive of 6 is required.

For example, when servo is performed on the reticle stage body 206, even if the reticle stage body 206 moves in an oscillating manner, the wafer stage 14 maintains the same velocity ratio as the reciprocal of the mass ratio. It makes an oscillatory movement similar to that of the stage body 206. In addition, since the momentum is stored, the center of gravity of the system is always constant, so that the base structure 200 does not rock. Therefore, the synchronization error of both scanning exposures is always zero.

When the exposure of one shot area on the wafer W is completed in this way, the stage main control system 260 drives the linear motors 240 and 242 via the drive circuit 256.
Is driven to position the shot area next to the exposed shot on the wafer W in the exposure field of the projection optical system PL (stepping is performed). After this positioning,
The stage main control system 260 drives the linear motor 216 via the main scanning drive system 255 to drive the reticle stage body 2
06 is scanned in the opposite direction (+ X direction) to start exposure of the shot. In this case, the wafer stage 14 is scanned in the −X direction at a speed of ¼ of the reticle stage body 206.

Thereafter, similarly, the exposure of the shot area on the wafer is performed by the step-and-scan method.

As described above, according to the first embodiment, the mass ratio Mr / Mw between the stage body on the reticle side and the stage body on the wafer side is set equal to the reduction magnification Mp1 of the projection optical system PL. The reticle structure 206 and the wafer stage 12 have a simple structure without providing a complicated synchronization control circuit or the like, and without using a stage having excellent dynamic characteristics or a special vibration isolator such as an active vibration isolator.
It is possible to always scan and with zero synchronization error based on the law of conservation of momentum. Further, since the reticle stage body 206 and the wafer stage 14 (wafer stage bodies 208 and 220) move in opposite directions in accordance with the law of conservation of momentum, the center of gravity position of the entire apparatus body including the base structure 200 in the X direction almost changes. In addition, the effect that the shake of the device is reduced can be obtained.

By the way, in the first embodiment, as described above, the scanning direction (X) is provided between the reticle stage body 206 and the substrate stage (wafer stage bodies 208, 220).
Direction), a linear motor 216 is disposed, the wafer stage 14 is supported by an air bearing so as to move one-dimensionally in the X direction on the base structure 200 in a non-contact state, and the reticle stage body 206 is structured as a base structure. Body 200
It is supported by an air bearing so as to move one-dimensionally in the X direction in a non-contact state above.

Therefore, while the drive current is being supplied to the drive coil portion 216B of the linear motor 216, the relative positional relationship between the reticle R and the wafer W in the X direction is controlled according to the law of conservation of momentum. However, the linear motor 2
When the power supply to 16 is cut off, the force for maintaining the relative positional relationship between the reticle stage body 206 and the wafer stage 14 in the X direction is lost.

Therefore, when the power supply to the linear motor 216 is cut off, the vibration from the vibration source (such as another motor) inside the exposure apparatus, the vibration from the air conditioner outside the exposure apparatus, and the exposure apparatus are installed. The reticle stage body 206 is subject to vibrations of the floor surface or a slight inclination of the entire exposure apparatus.
The relative positional relationship between the wafer stage 14 and the wafer stage 14 may gradually deviate.

In this case, the relative displacement of the reticle stage body 206 and the wafer stage 14 in the X direction is made zero by devising the coil arrangement of the linear motor 216, the winding structure of each coil, the supply control of the drive current, and the like. It is also possible to use a linear motor that is capable of servo control so as to maintain it. In this case, the relative positional relationship between the reticle R and the wafer W in the X direction can be easily stopped simply by controlling the current supplied to the linear motor 216. However, even in that case, there is a possibility that the reticle stage body 206 and the wafer stage 14 may be integrated with each other and be displaced on the base structure 200 in the X direction due to various vibrations, the tilt of the exposure apparatus, and the like.

In either case, the reticle stage body 20
No. 6 is no different in that the wafer stage 14 is displaced with respect to the base structure 200. This means that the optical axis (or illumination light flux) of the illumination system 212 fixed with respect to the base structure 200 and the scanning exposure. This means that the relative positional relationship in the X direction with the reticle R, which should be set at the start, changes, and this has a significant effect on the exposure sequence of the step & scan system.

In order to eliminate such inconvenience, the second linear motor 214 functions. That is, in the exposure apparatus 100 according to the first embodiment, the first linear system that controls the relative positional relationship between the reticle stage body 206 and the wafer stage 14 (wafer stage bodies 208 and 220) at a speed ratio according to the law of conservation of momentum. In addition to the motor 216, the base structure 2
Since the second linear motor 214 for controlling the absolute position of the reticle stage body 206 with respect to 00 is provided, the reticle stage body 206 and the wear stage 14 (wafer stage bodies 208, 220) are separated according to the momentum conservation law during scanning exposure. Is moved in the opposite direction, the power supply terminal of the drive coil portion 214B of the second linear motor 214 is opened to put it in an unloaded state. On the other hand, when the absolute position of the reticle stage body 206 is controlled, the base structure 20
The second linear motor 214 can be servo-controlled based on position information and velocity information from the interferometer RIFx for measuring the position of the reticle stage body 206 in the X direction with respect to zero.

Therefore, by linearly controlling each linear motor in accordance with the S & S type wafer exposure sequence,
It is possible to always accurately control the position of the reticle R with respect to the illumination light flux.

Further, since the positional relationship between the reticle R and the wafer W after the exposure processing is completed can be kept unchanged from the positional relationship at the start of the exposure processing, it is possible to automatically perform the reticle replacement and the wafer replacement. There is also an advantage that displacement of the delivery position between the transfer mechanism and the arm or the like can be prevented.

In the first embodiment, the case where an inverted optical system for projecting the inverted image of the pattern of the reticle R onto the wafer W is used as the projection optical system is illustrated, but a vertically symmetrical circuit pattern is exposed. In such a case, it is possible to use an erecting optical system for forming an erect image of the circuit pattern on the photosensitive substrate as the projection optical system.

Further, in the above-mentioned first embodiment, the case where the reduction magnification of the projection optical system is 1/4 has been illustrated, but the reduction magnification of the projection optical system may be any magnification. For example, even if the reduction ratio is 1 (one size), the merit of the present invention is great. That is, according to the present invention, since the momentum is saved, the position of the center of gravity of the system does not move due to the movement of the stage, and the body does not shake due to the reaction force due to the movement of the stage. This eliminates the need for an expensive anti-vibration device, etc., and even if one stage vibrates, the other stage moves in a similar vibrating manner, and no synchronization error occurs. is there.

<< Second Embodiment >> Next, a second embodiment of the present invention will be described with reference to FIG. Here, the same reference numerals are used for the same or equivalent components as in the first embodiment described above, and the description thereof will be simplified or omitted. In the second embodiment, as shown in FIG.
14 is functionally related to the power generation coil 257 and a load circuit 258 for regenerative braking that consumes the current from the coil 257. The other structure of the control system and the other device structure are the same as those in the first embodiment.

In the second embodiment, the reticle stage body 2 during scanning exposure is utilized by using the second linear motor 214.
06 and the wafer stage 14 (wafer stage body 208,
220) and the speed ratio thereof is, for example, within a range of about ± 0.1%. p. A regenerative control circuit for finely adjusting the resolution on the order of m, specifically a power generation coil 257 and a load circuit 258 in FIG. 5, is provided to make a minute change in the transfer magnification in the scanning direction (design in the scanning direction on the wafer W). When the dimension is 35 mm, it is expanded / contracted by about several hundred nm as a whole).

This will be described in more detail. The power generating coil 25
7 is configured by providing a special power-generating coil in the second linear motor 214 or using a driving coil also for power generation. The first linear motor 216 reverses the reticle stage and the wafer stage. While moving in the direction, the load circuit 258 (including an appropriate load resistor) is connected to the terminal of the power generation coil to perform regenerative control, thereby increasing the dynamic load of the reticle stage body 206 in the X direction. Then, the speed ratio between the reticle stage body 206 and the wafer stage 14 is slightly changed.

In order to control the amount of regenerative braking, the load circuit 258 is constructed so that the current from the coil 257 for power generation is passed through the load resistor via the high speed switching element or the like, and the switching element is turned on / off. The frequency, the duty ratio of the on-time and the off-time, etc. may be varied over a wide range.

Here, the speed ratio Vw / Vr is set to the reduction ratio M
The second linear motor 21 for fine adjustment with p1
The load generating circuit 257 (see FIG. 5) integrated with the driving coil unit 214B of No. 4 and the load circuit 258 are used to control so as to apply a dynamic load to the moving direction of the reticle stage body 206. The load circuit 258 acts as a variable load resistor with respect to the power generation coil 257, and the current drawn from the power generation coil 257 is supplied to the main scanning drive circuit 25.
It has a function of changing it substantially continuously in accordance with a control command from 5.

During scanning exposure, reticle stage body 206
Tries to move at speed Vr, but power generation coil 257
If an appropriate load resistor is connected to the terminal of, the momentum corresponding to the energy consumed by the load resistor is added to the reticle stage body 206. This corresponds to increasing the apparent mass Mr of the reticle stage body 206 by a minute amount. Therefore, the speed ratio Vw between the wafer stage 14 and the reticle stage body 206 is Vw.
/ Vr is finely adjusted.

In this case, since the apparent mass of the reticle stage body 206 acts only in the increasing direction, the mass ratio Mr / Mw becomes large and the speed ratio Vw / Vr becomes M.
It is adjusted in the direction of p1 <(Vw / Vr). Therefore, the mass of each stage body is set so that the mass ratio Mr / Mw in the stationary state becomes slightly smaller than the reduction ratio Mp1, and the regenerative braking amount is always adjusted appropriately during scanning exposure. The speed ratio and the reduction ratio may be matched.

On the other hand, when the wafer stage 14 and the reticle stage body 206 are scanningly moved in opposite directions according to the law of conservation of momentum, the second linear motor 214 is moved.
When the reticle stage body 206 is driven by supplying power to the drive coil portion 214B of the reticle stage body 206,
Since the apparent dynamic mass of can be slightly reduced, it is also possible to adjust the speed ratio Vw / Vr in the direction of Mp1> (Vw / Vr).

According to the second embodiment described above, the scanning speed ratio between the reticle R and the wafer W during scanning exposure can be finely adjusted very easily by controlling the regenerative braking amount (current value from the power generation coil). From reticle R and wafer W
By detecting the speed ratio between and from the measurement results of the interferometer and controlling the regenerative braking amount so that the detected value becomes a preset value, the transfer magnification in the scanning direction can not only be finely adjusted. It is also possible to adjust the transfer distortion (distortion) by subtly changing the speed ratio between the scanning start portion and the end portion of the shot area on the wafer W and the speed ratio of the central portion of the shot area.

In the first and second embodiments described above, the linear motor 214 is provided to move the reticle stage body 206 independently on the base structure 200 in the scanning direction, but instead of this or together with this, the linear motor 214 is provided. The positions of the first and second wafer stage bodies 208 and 220 in the X direction can be securely stopped, and the first and second wafer stage bodies 208 and 2 can be fixed.
In order to independently move 20 on the base structure 200, the base structure 200 and the first wafer stage body 2
08, a third linear motor that generates thrust in the X direction may be provided, and the third linear motor may be servo-controlled based on the measurement value of the wafer interferometer 252 (WIFx).

Next, in the case where a third linear motor (not shown) is added to the apparatus of the second embodiment, when scanning exposure is performed by aligning the pattern area of the reticle R with the shot area on the wafer W. The sequence of the above will be described.

(1) The reticle stage body is moved to the loading position, and the reticle R is set on the stage.
At this time, the wafer stage 14 may be moved in the opposite direction in accordance with the law of conservation of momentum associated with the movement of the reticle stage body, or may be forced to stand still at a predetermined position by servo-controlling the third linear motor. Good.

(2) The reticle stage body 206 and the wafer stage body 220 are set so that the stage bodies 206 and 20 are set at predetermined positions with respect to the image field of the projection optical system.
8 and 220 are moved so that the reference mark fixed on the wafer stage body 220 and the alignment mark on the reticle R are passed through the projection optical system PL to detect the alignment detection system 23.
Photoelectric detection is mutually performed at 2 and the fine movement stage 210 on the reticle stage body 206 is controlled so that the reticle R is aligned in the X, Y, and θ directions with respect to the moving coordinate system of the wafer stage body 220. Reticle R is wafer stage body 2
When aligned with the moving coordinate system of 20, the X and Y measurement values from the reticle interferometer 250 and the X and Y measurement values from the wafer interferometer 252 are stored as primary alignment achievement positions. . After that, the positional relationship is managed so that it is immediately reproduced.

(3) Wafer W on Wafer Stage Body 220
The wafer stage body 220 is moved to a predetermined loading position in order to be placed thereon. After that, the wafer stage body 220 is moved so that the alignment marks formed in association with some shot areas on the wafer W are sequentially arranged within the field of view of the projection optical system PL, and each alignment mark is moved. The alignment detection system 230 sequentially detects the projection optical system PL. Based on the detection result, the relative positional relationship (X, Y, θ directions) between the arrangement coordinate system of the shot area on the wafer W and the pattern area of the reticle R is determined.

(4) When a positional deviation occurs in the X direction among the determined positional relationships, the third linear motor is driven to servo-lock so that the wafer stage 14 is not displaced with respect to the base structure. In this state, the first linear motor 216 is driven to finely move the reticle stage body 206 in the X direction with respect to the wafer stage 14. A relative position error in the Y direction between the shot array coordinate system on the wafer W and the pattern area of the reticle R is corrected by the wafer stage body 220 or the fine movement stage 210 on the reticle stage body 206, and a relative position error in the θ direction. Is a wafer stage body 220 using linear motors 240 and 242.
It is corrected by a minute rotation of. The θ stage may be separately provided on the wafer stage body 220.

(5) When the pattern area of the reticle R and the shot arrangement coordinate system on the wafer W are precisely aligned in the X, Y, and θ directions in this way, the X of the reticle stage body 206 and the wafer stage body 220 is X. , The relative positional relationship in the Y direction is read from the interferometer and stored as the secondary alignment achievement position. The secondary alignment achievement position is used as a reference for managing the movement position of each stage body during the exposure processing of the wafer W.

(6) Next, the reticle stage body 206 is positioned in the X direction so that the pattern area on the reticle R is located at the position where the irradiation of the illumination light beam is started, and one shot area on the wafer W is exposed. The wafer stage 14 is positioned in the X direction so as to come to the above position.

(7) Then, the first linear motor 216
Drive the reticle stage body 2 according to the law of conservation of momentum.
06 and the wafer stage 14 are moved in opposite directions at a predetermined speed ratio corresponding to the imaging magnification Mp1 of the projection optical system PL.
At this time, fine adjustment of the transfer magnification in the scanning direction requires precise measurement of the change in the speed ratio (or the change in the relative positional relationship) when it is necessary to suppress the change in the speed ratio between both stages within the allowable range. Based on the result, the second linear motor 214 and the third linear motor may be positively controlled to continuously finely adjust the apparent dynamic mass of the reticle stage body 206 or the wafer stage 14.

<< Modification >> Next, a modification is shown in FIG.
Description will be made based on (B).

The exposure apparatus of this modification is characterized in that not only the wafer W as a photosensitive substrate but also the reticle R as a mask is held horizontally on the reticle stage 16.

This exposure apparatus is a projection optical system including a reticle stage 16 and a substrate stage 14 which are levitationally supported on a surface plate 12 via an air bearing (air bearing) 13 and a reflection optical system for reducing and projecting a circuit pattern. PL
And a light source 20.

In the exposure apparatus of this modified example, the substrate stage 14 is floated and supported on the surface plate 12 and is movable in the X-axis direction, and the first stage 14A.
It has a second stage 14B that is driven in the Y-axis direction by a linear motor. This second stage 14B
The wafer W is held on the top.

As shown in FIG. 6 (B), the reticle stage 16 is arranged so as to straddle the first stage 14A, and the coil 1 is placed between both stages 16 and 14A.
Linear motor 18 consisting of 8A and magnet 18B,
18 is interposed.

When the exposure light from the light source 20 illuminates the reticle R from below via the illumination optical system (not shown), the image of the circuit pattern in the elongated illumination area (corresponding to the exposure field of the projection optical system) is projected. The image is reduced and projected onto the wafer W via the PL.

Therefore, also in this modification, if the ratio of the masses of the reticle stage 16 and the substrate stage 14 is set to be the same as the reduction magnification Mp1 of the projection optical system PL, both of them are the same as in the above embodiments. The scanning error of the circuit pattern is performed when the synchronization error of the stages 16 and 14 is always zero. The same effect can be obtained.

In the first and second embodiments described above, the case where the photosensitive substrate is held horizontally on the substrate stage, that is, the case where a horizontally placed substrate stage is used is illustrated. However, the photosensitive substrate is perpendicular to the substrate stage. It is possible to apply the present invention to an exposure apparatus which is held by the substrate, that is, which uses a vertically placed substrate stage.

Further, in the above-mentioned first and second embodiments, the case where the linear motor is used as the drive means for driving the second stage in the non-scanning direction is illustrated, but the present invention is not limited to this. Alternatively, the feed screw mechanism may be used to drive the second stage in the non-scanning direction.

[0094]

As described above, according to the present invention,
An unprecedented advantage that can reduce the stress generated in the structure that constitutes the device, suppress the tilt and swing of the entire device with a simple structure, and improve the synchronization performance between the mask stage and the substrate stage. There is an effect.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing an exposure apparatus of the first embodiment.

3 is a schematic plan view of the device of FIG.

4 is a block diagram showing a configuration of a control system of the apparatus of FIG.

FIG. 5 is a block diagram showing a configuration of a control system of the device of the second embodiment.

6A and 6B are views showing a modified example, in which FIG. 6A is a schematic front view and FIG. 6B is a right side view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 exposure apparatus 12 surface plate (base member) 13 air bearing (air bearing) 14 wafer stage (substrate stage) 16 mask stage 18 first linear motor 100 exposure apparatus 200 base structure (base member) 206 reticle stage body (mask Stage) 208 first wafer stage body (first wafer stage) 214 second linear motor 216 first linear motor 220 second wafer stage body (second wafer stage) 232 half TTL alignment detection system 257 generator coil (regenerative braking) 258 load circuit (part of regenerative braking control circuit) R reticle (mask) W wafer (photosensitive substrate) PL projection optical system G1 first lens group (transmissive optical element) G2 second lens group (transmission) Optical element) G3 Third lens group (transmissive optical element) ) BS beam splitter (optical splitter) MR concave mirror (reflection optical element)

Claims (8)

[Claims] 1. An exposure apparatus for transferring a pattern formed on the mask onto the photosensitive substrate via a projection optical system while synchronously scanning a mask stage holding the mask and a substrate stage holding the photosensitive substrate. A substrate stage that is levitationally supported on a base member via an air bearing; a mass that is a reduction magnification of the projection optical system times the mass of the substrate stage, and the substrate stage has an air bearing on the base member. An exposure apparatus comprising: a floating and supported mask stage; and a first linear motor that is provided between the stages and drives the stages in opposite directions along the scanning direction. 2. The exposure apparatus according to claim 1, wherein the projection optical system is an optical system that projects an inverted image of a pattern formed on the mask on the photosensitive substrate. 3. The photosensitive substrate is held horizontally on a substrate stage, the mask is held vertically on the mask stage, and the projection optical system comprises a plurality of transmissive optical elements, a light splitter and a reflector. 3. An optical system including an optical element for projecting the pattern of the mask arranged on the object plane onto the photosensitive substrate arranged on the image plane at a predetermined reduction magnification. The exposure apparatus according to. 4. The exposure according to claim 3, further comprising a half TTL alignment detection system capable of detecting both the alignment mark formed on the mask and the alignment mark on the photosensitive substrate via the light splitter. apparatus. 5. A second linear motor for driving the mask stage in the scanning direction is provided between the base member and the mask stage. The exposure apparatus according to any one of claims. 6. A third linear motor for driving the substrate stage in the scanning direction is provided between the base member and the substrate stage, according to claim 3 or 5. The exposure apparatus described. 7. A regenerative braking control circuit that finely adjusts a speed ratio of the first linear motor during scanning of the both stages is provided together with at least one of the second linear motor and the third linear motor. The exposure apparatus according to claim 5, wherein the exposure apparatus is an exposure apparatus. 8. The substrate stage moves in the scanning direction integrally with the first stage, which holds the photosensitive substrate, and a first stage driven in the scanning direction by the first linear motor. 8. The exposure apparatus according to claim 1, further comprising a second stage guided by the first stage and movable in a direction orthogonal to the scanning direction.