JP2000077315A - Exposure method and aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expose with a light beam in an always adequate state of an optical axis, regardless of the positions of a stage, without decreasing the throughput thereof. SOLUTION: When a wafer stage WS is put at a measuring position (wafer delivery position), positional information (displacement of angle and position) of a light beam 1L from a light source 12 is measured by a monitor unit 29. On the basis of the positional information and information of optical-axis dislocation of the light beam 1L between the light beam 1L on the stage WS at the measuring position and the light beam 1L on the stage WS in a movable range thereof at a plurality of reference positions (for example, positions corresponding to each shot-region exposure) selected at a distance from the measuring position, the optical axis of the light beam 1L is adjusted by the optical axis compensating systems 23 and 24, when the exposure is carried out for each shot region of a wafer W. In this case, the information on dislocation is measured beforehand and stored in a memory unit 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a semiconductor integrated circuit,
The present invention relates to an exposure method and an exposure apparatus used when manufacturing a liquid crystal display element, a thin film magnetic head, other micro devices, and the like by using a lithography technique.

[0002]

2. Description of the Related Art In a photolithography process, which is one of semiconductor device manufacturing processes, a mask or a reticle is used as an exposure apparatus for transferring a pattern formed on a photoresist onto a wafer coated with a photoresist. A stepper that reduces and projects a pattern image onto a shot area on a wafer is often used.

[0003] As a stepper, a step of exposing a pattern to a shot area on a wafer at a time, sequentially moving the wafer, and repeating the batch exposure for another shot area.
The mask and wafer are moved synchronously and scanned and illuminated with slit light of a rectangular or other shape to illuminate the wafer from the viewpoint of the AND-repeat method or, more recently, the expansion of the exposure range and the improvement of the exposure performance. Expose the shot area sequentially,
Move the wafer sequentially to scan other shot areas.
A step-and-scan type in which exposure is repeated has also been developed and is being put to practical use.

In this type of projection exposure apparatus, g-ray (wavelength: 436 nm) or i-ray (wavelength: 365 nm) of a mercury lamp is used as exposure light. shorter wavelength has progressed to correspond, KrF (wavelength 248 nm) or ArF (wavelength 193 nm), more excimer laser light such as _{F 2} (wavelength 153 nm) is used, or their use is being considered.

Since the light source (beam source) for emitting such excimer laser light is generally large, it is separated from the main body of the exposure apparatus and installed on the same floor, or the exposure main body is installed. Is installed in the space under the floor of the clean room. For this reason, the optical axis (center of the intensity distribution) of the light beam (illumination light) is regularly or irregularly changed due to a change in a relative position due to regular or irregular vibration between the exposure main body and the light source. Fluctuate. When the optical axis of the light beam fluctuates, for example, when the optical axis of the light beam incident on the fly-eye integrator deviates beyond an allowable range, the light amount of the light beam emitted from the fly-eye integrator fluctuates (decreases).

For this reason, conventionally, the shift of the optical axis of a light beam is regarded as a change in illuminance or light amount, and the light amount is controlled by controlling the output of a light source or the dimming rate of the light beam, or the exposure time is adjusted. According to this, if the optical axis of the light beam incident on the fly-eye integrator deviates from the allowable range, it may not be possible to cope with the light amount control, and the adjustment of the exposure time may reduce the processing time. Increase, resulting in a decrease in throughput. For this reason,
A change in the optical axis of the light beam has been detected, and adjustment has been performed to offset the shift of the optical axis of the light beam.

[0007]

However, since the exposure main body is provided with a substrate stage or the like as a movable portion, the exposure main body may not move along the optical axis of the light beam even when the center of gravity of the exposure main body changes due to the movement. Since the displacement occurs, even if the stage is adjusted to cancel the displacement of the optical axis when the stage is at a specific position, the displacement of the optical axis still occurs when the stage is at another position. was there.

In particular, in an exposure apparatus of a step-and-repeat method or a step-and-scan method, a substrate stage is relatively moved with respect to a projection optical system so as to sequentially move a plurality of shot areas on a wafer. Since the exposure is repeated, strictly speaking, the optical axis shift due to the change of the stage position occurs for each exposure for each shot area, and in order to realize more precise exposure processing to respond to further miniaturization of micro devices, It is necessary to consider such a point.

It is considered that such a problem can be solved by measuring and adjusting the deviation of the optical axis immediately before performing exposure processing on each shot area on the wafer. Requires a certain amount of time, so that if it is performed for each shot area, a new problem will occur that the throughput will be significantly reduced.

[0010] The present invention has been made in view of such problems of the prior art.
It is an object of the present invention to perform exposure with an optical axis of an exposure energy beam always appropriate regardless of the stage position without lowering the throughput.

[0011]

In the following description, the present invention will be described with reference to the member codes shown in the drawings showing the embodiments. However, the present invention is not limited to the members shown in the drawings attached with.

1. To achieve the above object, the exposure method according to the first aspect of the present invention provides an exposure energy beam (I
L) is irradiated onto the mask (R), and an image of the pattern of the mask is projected onto the substrate (W) to expose the substrate. In the exposure method, a stage (WS) for mounting the substrate includes: When at a predetermined measurement position, the position information of the optical axis of the exposure energy beam is measured, and the measured position information of the optical axis, and when the stage is at the measurement position and the movable range of the stage Exposes the substrate mounted on the stage based on each of the displacement information of the optical axis of the exposure energy beam when the stage is at a plurality of positions selected apart from the measurement position. The optical axis of the exposure energy beam is sometimes adjusted.

The displacement of the optical axis of the exposure energy beam depending on the position of the stage on which the substrate is mounted is caused by the mechanical rigidity of the exposure main body and the change of the center of gravity of the exposure main body accompanying the driving of the stage. And reproducibility depending on the position of the stage. In the present invention, focusing on this point, when the stage is at a predetermined measurement position (for example, a substrate transfer position) and when the stage is at a plurality of positions selected within its movable range (for example, for each shot area, Relative to the optical axis of the exposure energy beam when the stage is at the measurement position, and position information of the optical axis measured when the stage is at the measurement position. The optical axis of the exposure energy beam is adjusted based on the displacement information. Thus, the exposure process can be performed in a state where the shift of the optical axis depending on the position of the stage at the time of exposure is canceled, so that the exposure can always be performed with the optical axis being appropriate regardless of the stage position. Become like Further, after the optical axis position information is actually measured at a predetermined measurement position, it is not necessary to measure the optical axis position information during a series of exposure processing for each shot area, so that a decrease in throughput is also suppressed. be able to.

In particular, if the predetermined measurement position is set at the substrate transfer position, the stage has been stopped for a relatively long time at the substrate transfer position for the transfer of the substrate. Since the position information of the optical axis can be measured by using the optical axis, a decrease in the throughput for the measurement of the optical axis can be substantially eliminated, and the measurement of the optical axis can be performed in a state where the exposure main body is sufficiently stable and sufficient. Since the measurement can be performed over a long time, the accuracy of the measurement can be increased.

2. To achieve the above object, the exposure method according to the second aspect of the present invention provides an exposure energy beam (I
L) is applied to the mask (R), and the pattern of the mask is transferred to each of the plurality of shot areas on the substrate (W). Corresponding to the position of the stage, optical axis deviation information of the exposure energy beam is respectively detected, and based on the detected optical axis deviation information when exposing each shot area on the substrate, the exposure energy beam is detected. The optical axis adjustment is performed.

The displacement of the optical axis of the light beam depending on the position of the stage on which the substrate is placed is caused by the mechanical rigidity of the exposure main body and the change in the position of the center of gravity of the exposure main body accompanying the driving of the stage. There is reproducibility depending on the stage position. In the present invention, focusing on this point, corresponding to the position of the stage when exposing a plurality of shot areas on the substrate,
The shift information of the optical axis of the exposure energy beam is detected in advance, and when exposing each shot area on the substrate, the optical axis is adjusted based on the shift information of the optical axis. Exposure can always be performed with an appropriate optical axis. Further, after measuring the optical axis shift information for each of the shot areas, it is not necessary to measure the information during a series of exposure processing for each of the shot areas, so that a decrease in throughput can be suppressed to a low level.

3. To achieve the above object, an exposure apparatus according to a third aspect of the present invention is an exposure apparatus that exposes a substrate by projecting an image of a pattern formed on a mask (R) onto the substrate (W). A beam source (12) for generating an exposure energy beam (IL), and an exposure body installed on a different base from the beam source for transferring the pattern of the mask onto the substrate under the exposure energy beam The exposure when the unit (11) and the stage (WS) for mounting the substrate are at a predetermined measurement position and when the stage is at a plurality of reference positions separated from the measurement position A storage device (20) in which displacement information of the optical axis of the energy beam is stored and held, respectively.
a), a detection device (29) for detecting a shift amount of an optical axis of the exposure energy beam when the stage is at the measurement position, and a detection result of the detection device and displacement information held in the storage device. Adjusting devices (23, 24) for adjusting the optical axis of the exposure energy beam based on According to the present invention, there is provided an exposure apparatus suitable for performing the exposure method according to the first aspect of the present invention.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the overall configuration of a step-and-scan type projection exposure apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a main body of the exposure apparatus (exposure main body), and reference numeral 12 denotes an exposure light source (beam source) for supplying the exposure main body 11 with an ArF excimer laser beam as an exposure energy beam. These exposure main unit 1
The exposure light source 1 and the exposure light source 12 are configured independently of each other and installed on the same floor in a clean room (not shown). The exposure light source 12 may be installed on the same or different floor outside the clean room, or may be installed in a utility space (machine room) defined below the clean room floor. The exposure main body 11 and the exposure light source 12 are installed via anti-vibration devices, respectively. A beam matching unit (BMU: optical axis matching device) 13 is provided between the exposure main body 11 and the exposure light source 12.

Next, the configuration of the exposure main body 11 will be described. In the following description, the Z axis is taken parallel to the optical axis of the projection optical system 14, the X axis is perpendicular to the plane of the drawing in a plane (horizontal plane) orthogonal to the Z axis, and the Y axis is parallel to the plane of FIG. The explanation will be made taking the axis. The direction parallel to the Y axis is the scanning direction (scanning direction).

The exposure main body 11 is housed in a chamber (not shown). A surface plate 15 is provided on the floor of the chamber, and a wafer stage WS is disposed on the surface plate 15. The wafer stage WS is moved by a linear motor or the like.
And an XY stage 16 moving in the Y direction and a Z stage 17 mounted on the XY stage 16. A wafer holder (not shown) is suction-held on the Z stage 17, and a wafer W to be exposed to which a photoresist is applied is suction-held by the wafer holder. The Z stage 17 has a function of finely moving the wafer W in the rotation direction and a focus / leveling function of making the surface of the wafer W coincide with the image plane of the projection optical system 14.

A movable mirror 18 is fixed on the Z table 17 of the wafer stage WS, and a laser interferometer 19 irradiates the movable mirror 18 with a laser beam and receives the reflected light, whereby the wafer stage WS The position is measured, and the measured value is supplied to the control device 20, which controls the movement of the wafer stage WS.

Further, a projection optical system 14 is arranged above the wafer table WS, and a reticle stage RS is arranged further above the projection optical system 14, and a pattern to be transferred onto the reticle stage RS is formed. The reticle R is held by suction. The reticle stage RS has a function of being moved in the Y direction by a linear motor or the like, and of being finely moved in the X direction, the Y direction, and the rotation direction. The movable mirror 21 is fixed on the reticle stage RS, and the laser interferometer 22 irradiates the movable mirror 21 with laser light and receives the reflected light, whereby the position of the reticle stage RS is measured. The value is supplied to a control device 20, which controls the movement of the reticle stage RS. An illumination optical system is arranged further above the reticle stage RS.

Light beam (illumination light) I from the exposure light source 12
L is an optical axis correction mirror 23, an optical axis correction herb 2
4, reflection mirror 25, reflection mirror 26, lens group 27,
The light is introduced into the illumination optical system of the exposure main unit 11 via the beam matching unit 13 having the beam splitter 28. The light beam introduced into the exposure main body 11 passes through an optical axis correction mirror 31, an optical axis correction harving 32, and a beam splitter 33 to a fly-eye lens unit 34 for making the intensity distribution of the light beam uniform. Incident. The fly-eye lens unit 34 is configured, for example, by arranging a second-stage fly-eye lens with respect to a first-stage fly-eye lens via a relay lens system. The illustrated variable aperture stop is arranged. The light beam emitted from the aperture stop reaches a reflection mirror 35 via a field stop and a relay lens system (not shown), and the reflected light illuminates a reticle R on a reticle stage RS via a condenser lens 36.
The light beam IL has a slit-shaped illumination area elongated in the X direction on the pattern forming surface (lower surface) of the reticle R. Then, under the light beam IL, an inverted image of the pattern in the illumination area of the reticle R is projected onto the projection optical system 14.
Via a predetermined projection magnification β (β is, for example, 1/4, 1 /
5), a rectangular exposure area on the wafer W is exposed.

At the time of scanning exposure, the illumination area
In synchronization with the movement of the reticle R in the + Y direction (or -Y direction) at the speed VR via the reticle stage RS,
With respect to the exposure area, the wafer W is moved through the wafer stage WS in the −Y direction (or + Y direction) at a speed β · VR (β
Is the projection magnification). The reticle R and the wafer W are each accelerated after the start of the approach, and after reaching a predetermined speed and moving at a constant speed, the irradiation of the light beam IL to the illumination area is started, and the transfer of the pattern of the reticle R is performed. Will be When the transfer to one shot area is completed, the irradiation of the light beam IL is stopped, and the next shot area is moved to the approach start position by the stepping of the wafer stage WS. The transfer of the pattern to each shot area is performed sequentially.

A light beam IL composed of ultraviolet pulse light emitted from the exposure light source 12 in a substantially horizontal plane in the + Y direction is shaped into a predetermined sectional shape by a beam expander (not shown). Light beam IL that has passed through the beam expander
Is almost downward (−Z direction) by the optical axis correcting mirror 23.
Is reflected by the reflecting mirror 25 in the + Y direction after passing through the optical axis correcting harbing 24, and is reflected by the reflecting mirror 2.
6, is reflected in the + Z direction and passes through the lens system 27,
The beam reaches the beam splitter 28. The main beam reflected in the + Y direction by the beam splitter 28 is supplied to the exposure main body 11. The sub-beam transmitted through the beam splitter 28 is incident on an optical axis shift monitor unit 29 having a CCD camera or the like for detecting an optical axis shift.

The optical axis correction system including the optical axis correction mirror 23 and the optical axis correction harving 24 is configured as shown in FIG. That is, the optical axis correcting mirror 23
Are supported by a fulcrum 41 and a Y-axis actuator 42 and an X-axis actuator 43 composed of a telescopic drive element such as a moving coil motor. The amount of expansion and contraction of the Y-axis actuator 42 and the X-axis actuator 43 is controlled by the control device 20. Is controlled by In addition, the optical axis correcting harving 24 is composed of an X herb 24X and a Y herb 24Y each made of a light-transmissive parallel plane glass. These X-harving 24X and Y-harving 24Y are slightly rotated by rotation motors 44 and 45, respectively.
Controlled by 0.

The light beam IL from the exposure light source 12 is reflected by the optical axis correcting mirror 23 substantially in the -Z direction, and then passes through the X harbing 24X and the Y harving 24Y. By appropriately expanding and contracting the X-axis actuator 42 and the Y-axis actuator 43 and slightly changing the angle of the optical axis correcting mirror 23, the angle (the traveling direction) of the reflected light becomes δθx about the axis parallel to the Y axis. , And an axis parallel to the X axis by δθy. Furthermore, X
By slightly rotating the harbing 24X around an axis parallel to the Y axis, the optical path of the light beam IL becomes δdx in the X direction.
Only the horizontal shift (position shift),
By a slight rotation about an axis parallel to the axis, the optical path of the light beam IL is laterally shifted by δdy in the Y direction. Therefore, the optical axis shift (angle shift and position shift) of the light beam IL can be appropriately corrected and controlled within a predetermined range.

Referring again to FIG. This optical axis correction system 2
The light beam IL that has passed through the light splitters 2 and 23 passes through a reflection mirror 25, a reflection mirror 26, and a lens system 27,
8 and a part of the incident light beam (for example,
(About 1%) is transmitted through the beam splitter 28 and is incident on the optical axis deviation monitor unit 29, where the deviation amount (angle deviation amount) in the traveling direction (incident angle) and the lateral shift amount (position deviation) Is detected, and the detection result is supplied to the control device 20. In addition, most of the light beam IL that has entered the beam splitter 28 (for example,
(About 99%) is reflected toward the exposure main body 11.

FIG. 3A shows the optical axis shift monitor unit 2.
9 shows the configuration of FIG. In the figure, the light beam IL transmitted through the beam splitter 28 is incident on a half mirror 51, and the light beam transmitted through the half mirror 51 passes through an appropriate neutral density filter 52 and a condenser lens 53 having a focal length f. , A two-dimensional image sensor 54 such as a CCD camera. The condenser lens 53 and the image sensor 54 constitute an angle shift monitor. As shown in FIG. 3 (C), the light flux I on the imaging surface 55 of the imaging element 54 is processed by processing the imaging signal of the imaging element 54 by the control device 20.
The displacement amounts Δx2 and Δy2 in the X direction and the Y direction with respect to a predetermined reference point 55a at the center of L2 are detected.

In this case, the imaging surface 55 of the imaging device 54
The incident surface of the fly-eye lens unit 34 shown in FIG. 1 is substantially in the relationship of an optical Fourier transform surface (pupil surface), and the angular deviation of the light beam IL around the Y axis is δθx ′, and the angular deviation around the X axis is Is δθy ′, and this and the displacement Δx
2, Δy2 has the following relationship.

Δx2 = f · δθx ′ (1A) Δy2 = f · δθy ′ (1B) At this time, when the angle shift amounts δθx ′ and δθy ′ with respect to the optical axis of the fly-eye lens unit 34 are 0, the position The reference point 55a on the imaging surface 55 is set so that the deviation amounts Δx2 and Δy2 become 0, and the control device 20 calculates the angle deviation of the light beam IL with respect to the exposure main body 11 from the expressions (1A) and (1B). The quantities δθx ′ and δθy ′ are calculated.

On the other hand, the light beam reflected by the half mirror 51 passes through a reflection mirror 56 and a reduction optical system 57 with a magnification m, and
The light is incident on a two-dimensional image sensor 58 such as a CCD camera. Between the reduction optical system 57 and the image sensor 58, an appropriate neutral density filter (not shown) for adjusting the amount of light incident on the image sensor 58 is provided. By processing the imaging signal of the imaging device 58 by the control device 20, as shown in FIG. 3B, on the imaging surface 59 of the imaging device 58, the X direction with respect to a predetermined reference point 59a of the center of the light beam, and the Y direction The displacement amounts Δx1 and Δy1 in the directions are detected.

In this case, the imaging surface 59 of the imaging device 58
Assuming that the displacement of the light beam IL in the X-axis direction is Δdx ′ and the displacement of the light beam IL in the Y-axis direction is Δdy ′, these positions are substantially conjugate to the incident surface of the fly-eye lens unit 34 in FIG. The following relationship exists between the deviation amounts Δx1 and Δy1.

Δx1 = m · δdx ′ (2A) Δy1 = m · δdy ′ (2B) Further, when the positional deviation amounts δdx ′ and δdy ′ with respect to the fly-eye lens unit 34 are 0, The imaging surface 59 is set so that the displacement amounts Δx1 and Δy1 become zero.
The above-mentioned reference point 59a is set, and the control device 20 calculates the positional deviation amounts δdx ′ and δdy ′ of the light beam IL with respect to the exposure main body 11 from the equations (2A) and (2B).

After calculating the angle shift amounts δθx ′ and δθy ′ and the position shift amounts δdx ′ and δdy ′, the controller 20
Sets the angle shift correction amounts δθx and δθy in the optical axis shift correction system shown in FIG. 2 to −δθx ′ and −δθy ′, respectively, and sets the position shift correction amounts δdx and δdy to −δdx ′, respectively. Set to -δdy '. That is, the angle shift amounts δθx ′, δ detected by the optical axis shift monitor unit 29
The drive of the optical axis correction mirror 23 and the optical axis correction harving 24 (24X, 24Y) is controlled so that θy ′ and the displacement amounts δdx ′, δdy ′ become 0, respectively. Accordingly, the angle shift amount and the position shift amount of the light beam IL with respect to the exposure main body 11 (hereinafter, collectively the optical axis shift amount), and the optical axis shift amount of the light beam IL with respect to the fly-eye lens unit 34 are reduced. It becomes almost 0.

Referring back to FIG. The reflected light (main beam) from the beam splitter 28 of the beam matching unit 13 is guided to the exposure main body 11, and is reflected almost upward (+ Z direction) by the optical axis correcting mirror 31, and then the optical axis is corrected. The beam reaches the beam splitter 33 through the application harbing 32. The main beam reflected in the + Y direction by the beam splitter 33 is supplied to a fly-eye lens unit 34. The sub-beam transmitted through the beam splitter 33 enters the optical axis deviation monitor unit 37.

The optical axis correcting mirror 31 and the optical axis correcting harving 32 have the same configuration as the optical axis correcting mirror 23 and the optical axis correcting harving 24 of the optical axis correcting system shown in FIG. Is omitted. The optical axis shift monitor unit 37 is also the optical axis shift monitor unit 29 shown in FIG.
Since the configuration is the same as that described above, the description thereof is omitted.

Next, the operation of collecting the optical axis shift amount (optical axis position information) according to the position of the wafer stage WS will be described. This operation is performed at the time of initial adjustment when the projection exposure apparatus is installed or at the time of maintenance of the projection exposure apparatus. The center (center of gravity) of wafer stage WS and the center (center of gravity) of reticle stage RS are moved on the optical axis of projection optical system 14, respectively. Since the optical axis of the projection optical system 14 is designed so as to pass substantially through the center of gravity of the mechanical unit excluding the two stages WS and RS, the two stages W
The state where S and RS are arranged in such a manner is considered to be the most stable state.

In this state, the correction amount by the optical axis shift correction system (the optical axis correction mirror 23 and the optical axis correction harving 24) of the beam matching unit 13 is set to 0, and the optical axis shift of the exposure main body 11 is set. While monitoring the amount of optical axis deviation by the monitor unit 37, using the optical axis deviation correction system (optical axis correction mirror 31 and optical axis correction harving 32),
The optical axis shift amount (the angle shift amount and the position shift amount) with respect to the incident surface of the fly-eye lens unit 34 is adjusted to be zero. At this time, the beam matching unit 13
The centers of the light fluxes IL2 and IL1 incident on the imaging surfaces 55 and 59 of the image sensors 54 and 58 of the optical axis shift monitor unit 29 are set as reference points 55a and 59a, respectively, and these reference points 55a and 59a are stored in the control device 20. The data is stored in the device (non-volatile memory) 20a. Thus, when the centers of the wafer stage WS and the reticle stage RS are located on the optical axis of the projection optical system 14, the optical axis deviation of the light beam IL with respect to the fly-eye lens unit 34 becomes zero, and the optical axis deviation The optical axis shift amount monitored via the monitor unit 29 also becomes zero.

Next, the wafer stage WS is moved to a predetermined measurement position (here, a substrate transfer position), and
In this state, the optical axis shift amount (angle shift amount and position shift amount) is measured by the optical axis shift monitor unit 29 of the beam matching unit 13, and this is used as initial position information of the optical axis of the light beam at the substrate transfer position. Storage device 2
0a. Thereafter, the wafers are sequentially moved to a plurality of positions selected in a grid pattern at a predetermined pitch in the movable range of the wafer stage WS, that is, the positions (exposure positions) of the wafer stage WS when exposing a plurality of shot areas on the wafer W. The stage WS is moved, and each of the displacement information of the optical axis of the light beam IL at the exposure position is compared with the difference (offset) from the optical axis shift amount at the substrate transfer position.
Is stored in the storage device 20a.

Based on the displacement information actually measured at each reference position, the pitch and the like are changed, a plurality of positions are newly selected in a grid pattern, and each of the displacement information at the new position is placed in the vicinity thereof. May be calculated using the least squares method or other approximation method based on the original displacement information corresponding to the position, and may be stored in the storage device 20a as the displacement information. The position at which the displacement information of the optical axis is collected is appropriately selected in consideration of the efficiency of the displacement information collection, the size of the wafer planned by the exposure apparatus, the shot arrangement, and the like.

Next, the actual exposure processing will be described.
This will be described with reference to the flowchart shown in FIG. First,
The wafer stage WS is moved to a transfer position (loading position) of the wafer W (ST1), and the wafer W is replaced (ST2). In parallel with this wafer W exchange process,
The position (wafer W)
Of the optical axis from the initial position (angle shift amount and position shift amount) at the (transfer position) (ST3).
Next, the displacement information stored in the storage device 20a is searched, and the displacement information on the position (exposure position) of the wafer stage WS corresponding to the shot area to be subjected to the exposure processing is read out. Displacement information and S
Based on the optical axis shift amount measured at T3, new optical axis displacement information at the exposure position is set (ST4).
Here, it is assumed that the displacement information stored and held in the storage device 20a has a one-to-one correspondence with the shot area of the wafer W.

Next, the beam matching is performed so as to cancel the optical axis shift amount indicated by the newly obtained optical axis displacement information.
By driving the optical axis correction harving 24 and the optical axis correction mirror 23 of the optical axis deviation correction system of the unit 13, the light beam I
The angle and position of the optical axis of L are adjusted (ST5). In parallel with this, the wafer stage WS is exposed at an exposure position, that is, a shot area to be exposed (in this case, a first shot area).
Moves so as to be located at the position projected by the projection optical system 14 (ST6). After that, an exposure process is performed on the wafer W (ST7), and then the displacement information is read out, the optical axis is corrected, the stage is moved, and the exposure process is repeated for the other shot areas in the same manner ( ST4
7) Exposure processing is performed on all shot areas on the wafer W (ST8). When the exposure processing for all shot areas is completed, the wafer stage WS
Is moved to the wafer transfer position (ST1), and the wafer W
Is exchanged (ST2), and in parallel with this, the optical axis shift amount at that position is measured (ST3), and the same processing is repeated thereafter.

Since the exposure apparatus normally processes wafers W having various shot arrangements, the position of wafer stage WS corresponding to each shot area does not always coincide with the reference position at which displacement information is measured. In that case, the displacement information about the reference position closest to the position of the wafer stage WS corresponding to each shot area can be used. Alternatively, based on displacement information about a plurality of reference positions in the vicinity, approximation by an approximation method such as linear approximation, curve approximation, or least squares approximation, and calculating appropriate displacement information about the stage position. May be used to correct the optical axis.

According to the present embodiment, wafer stage WS
When the stage is at a predetermined measurement position (transfer position of the wafer W) and when the stage is at a plurality of reference positions selected in a grid pattern within the movable range thereof, the displacement information (angle shift) of the optical axis of the light beam Amount and displacement amount) in advance,
In performing the exposure processing, when the wafer stage WS is at the measurement position, the optical axis position information (the amount of angular deviation and the amount of positional deviation) is measured, and based on the position information and the displacement information, the optical axis of the light beam is measured. Adjustments are made. This cancels out the optical axis shift due to a change in the relative position between the exposure main body 11 and the exposure light source 12 due to floor fluctuations, and cancels out the optical axis shift depending on the position of the wafer stage WS during exposure. Since the exposure process can be performed in a state where the wafer stage WS is positioned, the exposure process can always be performed with an appropriate optical axis regardless of the position of the wafer stage WS.

Further, since the deviation amount of the optical axis is measured at the transfer position of the wafer W, the deviation amount of the optical axis can be measured in parallel with the exchange processing of the wafer W, and the deviation amount of the optical axis can be measured. It is not necessary to stop the apparatus only for the measurement of, so that the throughput can be improved correspondingly.
Further, after the optical axis shift amount is actually measured at the transfer position of the wafer W, the optical axis shift amount does not need to be measured during a series of exposure processing for each shot area. Exposure processing can be performed on each shot area in an appropriate state without optical axis shift of the light beam IL, and there is no decrease in light amount due to optical axis shift,
Exposure with an appropriate light amount can be realized without depending on other light amount adjusting devices or the like.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

For example, in the above-described embodiment, the wafer transfer position is selected as the predetermined measurement position. This is because measurement and correction of the optical axis shift amount and its correction are performed in parallel with the wafer exchange operation. In order to improve the throughput, the wafer stage WS
May be set as the measurement position when the center of the projection optical system 14 is on the optical axis of the projection optical system 14, or another position may be set as the measurement position. Further, the displacement information may be only one of the angle shift amount and the position shift amount of the optical axis.
Further, in the above embodiment, the shift of the optical axis according to the position of the wafer stage WS is corrected.
If necessary, the position of reticle stage RS can be similarly corrected.

In addition, according to the present invention, the reticle and the wafer are synchronously moved, and the reticle and the wafer are scanned with slit light having a rectangular shape or other shape.
A step-and-scan type projection exposure apparatus that illuminates and sequentially exposes a shot area on a wafer and sequentially scans and exposes another shot area by moving the wafer, as well as a shot area on the wafer All at once,
The present invention can also be applied to a step-and-repeat type projection exposure apparatus in which wafers are sequentially moved and batch exposure is repeated for another shot area.

[0051] Further, the light source of the exposure apparatus is not particularly limited, ArF, excimer lasers, such as _{F 2,} EUV further having an oscillation spectrum in the soft X-ray region (extreme-
Even if it is meUltra Violet), it is applicable.

Further, the projection optical system 14 may be an optical system including only a reflection element (mirror or the like) other than all the optical elements being refraction elements (lenses), or a combination of a refraction element and a reflection element. A catadioptric optical system including elements (concave mirror, mirror, etc.) may be used.

[0053]

Since the present invention is constructed as described in detail above, the exposure can be performed with the optical axis of the exposure energy beam always in an appropriate state regardless of the stage position, and the throughput is hardly reduced. effective.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a main configuration of a projection exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating a configuration of an optical axis correction system according to the embodiment of the present invention.

3A and 3B are explanatory diagrams of an optical axis deviation monitor unit according to an embodiment of the present invention, wherein FIG. 3A is a configuration diagram, FIG. 3B is a diagram illustrating an imaging surface of an imaging device, and FIG. It is a figure showing an imaging side.

FIG. 4 is a flowchart showing processing during exposure processing according to the embodiment of the present invention.

[Explanation of symbols]

 W: wafer WS: wafer stage R: reticle RS: reticle stage IL: light beam (illumination light) 11: exposure body 12: exposure light source 13: beam matching unit 14: projection optical system 20: control device 20a: storage Apparatus 23, 31 Optical axis correction mirror 24, 32 Optical axis correction harving 28, 33 Beam splitter 29, 37 Optical axis deviation monitor unit 34 Fly eye lens unit 54, 58 Two-dimensional image sensor

Claims (9)

[Claims] 1. An exposure method for exposing a substrate by irradiating an exposure energy beam onto a mask and projecting an image of a pattern of the mask onto the substrate, wherein a stage for mounting the substrate has a predetermined measurement. When at the position, the position information of the optical axis of the exposure energy beam is measured, and the measured position information of the optical axis, and when the stage is at the measurement position and within the movable range of the stage, When exposing a substrate mounted on the stage, based on each of the displacement information of the optical axis of the exposure energy beam when the stage is located at a plurality of positions selected apart from the measurement position. An exposure method, wherein the optical axis of the exposure energy beam is adjusted. 2. The exposure method according to claim 1, wherein each of the plurality of positions is selected corresponding to a position of the stage when exposing a plurality of shot areas on the substrate. 3. The optical axis adjustment of the exposure energy beam corresponds to position information of the measured optical axis and a position of the stage or a position near the stage when the substrate is exposed among the plurality of positions. 2. The exposure method according to claim 1, wherein the method is performed based on the displacement information of the optical axis. 4. The pattern of the mask is transferred onto the substrate via a projection optical system, and the position of the stage when the center of the substrate substantially coincides with the optical axis of the projection optical system is determined. 3. The exposure method according to claim 1, wherein the measurement position is a measurement position. 5. The exposure method according to claim 1, wherein the position of the stage when the substrate is at the transfer position is the measurement position. 6. The exposure method according to claim 1, wherein the displacement information of the optical axis includes at least one of a position of the optical axis and an angle of the optical axis. 7. An exposure method for irradiating a mask with an exposure energy beam and transferring a pattern of the mask to each of a plurality of shot areas on a substrate, the method comprising: exposing a plurality of shot areas on the substrate. According to the position of the stage, optical axis deviation information of the exposure energy beam is respectively detected, and the exposure energy beam is detected based on the detected optical axis deviation information when each shot area on the substrate is exposed. An exposure method, wherein the optical axis is adjusted. 8. An exposure apparatus for exposing a substrate by projecting an image of a pattern formed on a mask onto the substrate, comprising: a beam source for generating an exposure energy beam; and a beam source installed on a base different from the beam source. An exposure main body for transferring the pattern of the mask onto the substrate under the exposure energy beam, and a stage for mounting the substrate at a predetermined measurement position, A storage device in which displacement information of the optical axis of the exposure energy beam at a plurality of reference positions separated from the measurement position is stored and held, and the exposure energy beam when the stage is at the measurement position A detection device for detecting the amount of deviation of the optical axis of the exposure device, and the exposure device based on the detection result of the detection device and the displacement information held in the storage device. Exposure apparatus comprising: the adjusting device for adjusting an optical axis of Energy beam, a. 9. The apparatus according to claim 8, wherein an image of a pattern formed on the mask is projected onto the substrate while the mask and the substrate are moved synchronously, and the substrate is exposed by scanning. Exposure equipment.