JP3360672B2 - Scanning exposure method, scanning exposure apparatus, laser device, and element manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scan type projection exposure apparatus and method for manufacturing semiconductor integrated circuits and liquid crystal devices.
And a scanning type laser device.

[0002]

2. Description of the Related Art Conventionally, many devices of this type have a function of correcting the image forming characteristics because the image forming characteristics must be maintained at a high level. Factors that cause the imaging characteristics to fluctuate include those that occur due to changes in the external environment such as atmospheric pressure and air temperature, and the fact that the projection optical system slightly absorbs the exposure light. With respect to changes in the environment, atmospheric pressure and the like are monitored by a sensor as disclosed in, for example, JP-A-61-183928, and corrections are made accordingly. For the absorption of exposure light, see, for example,
As disclosed in JP-A-78454, a method is known in which light energy incident on a projection optical system is measured, and a change in an imaging characteristic caused by exposure light absorption is calculated based on the measured value to perform correction. ing. In this case, light energy incident on the projection optical system via the mask is detected by, for example, a photoelectric sensor provided on the substrate stage. Further, in the projection optical system, in addition to the projection exposure light energy incident from the mask side, there is also light energy reflected on the photosensitive substrate and incident again on the projection optical system. It causes the imaging characteristics of the system to change. On the other hand, for example,
As disclosed in Japanese Patent Application Laid-Open No. 183522, measurement is performed by providing a photoelectric sensor that receives reflected light from a photosensitive substrate via a projection optical system and a mask in an illumination optical system, and forms an image forming characteristic by the reflected light energy. There is a method of calculating the change of the total imaging characteristic in consideration of the change of the image formation. In this case, since there is a photoelectric sensor in the illumination optical system, reflected light from an optical member, a mask pattern, or the like enters the photoelectric sensor at the same time as reflected light from the substrate. Therefore, in this method, a plurality of reference reflection surfaces having different known reflectances are provided on the substrate stage,
Each output ratio of the photoelectric sensor with respect to these reference reflecting surfaces is determined in advance, and the reflectance (reflected intensity) of the photosensitive substrate is determined based on the ratio. As described above, since the reflected light from the mask pattern is superimposed on the reflected light from the photosensitive substrate, the sensor output of a plurality of reference reflecting surfaces is obtained every time the mask is replaced, or the measurement and registration are performed in advance. Is required.

Conventionally, the amount of change in imaging characteristics due to absorption of exposure light has been obtained and corrected by the above-described method.

[0004]

SUMMARY OF THE INVENTION The above-mentioned conventional method is as follows.
It has been developed on the premise of a method of projecting and exposing the entire mask onto the photosensitive substrate at one time (referred to as a collective exposure method or a full field method). However, in recent years, a method of illuminating a part of a pattern region on a mask in a slit shape and exposing the mask and the photosensitive substrate while moving each other, a so-called scan exposure method, has been developed. This method not only has the advantage that the area illuminating the mask is smaller than the one-shot exposure method, so that the amount of image distortion or the nonuniformity of the illuminance is small. There is an advantage that large-area exposure can be performed without restriction.

However, in a scanning exposure type exposure apparatus, the energy incident on the projection optical system is not constant and changes while the mask is scanned with the slit-shaped illumination light. This is because, for example, the area of the light-shielding portion (chrome layer in the pattern) provided on the mask differs according to the position of the slit illumination area on the mask, so that the amount of energy incident on the projection optical system during scan exposure differs. It is caused by

Further, the reflected light from the mask pattern also varies depending on the position of the mask, and the accuracy of detecting the amount of energy reflected on the photosensitive substrate and incident on the projection optical system is inevitably deteriorated in the conventional case. Will be.

As described above, there has been a problem in that it is not possible to accurately determine the amount of change in the imaging characteristic due to absorption of exposure light and to perform correction.

An object of the present invention is to provide an accurate exposure amount to each point in a shot area on a substrate even in a scan exposure method using a pulse light source such as an excimer laser.

According to the present invention, for example, the mask (R) is moved in a predetermined scanning direction with respect to an illumination area of pulsed illumination light, and the substrate (W) is moved in a direction corresponding to the scanning direction. In the scanning exposure method for scanning and exposing a substrate, at least the edge of the intensity distribution of the illumination light in the scanning direction is inclined, and the intensity distribution is half (Im / 2) of the intensity (Im) of the illumination light. Pulses of the illumination light are emitted at intervals of such a distance that the width (XPs + ΔXs) of the defined illumination area IA in the scanning direction is exactly divisible by a predetermined integer Np, and the intensity of the illumination light in the direction orthogonal to the scanning direction. The exposure amount control for the substrate is performed according to the unevenness.

[0010]

The exposure light is controlled by giving an inclination to the end of the illuminance distribution of the illumination light in the scanning direction and taking into account the intensity unevenness of the illumination light in the non-scanning direction orthogonal to the scanning direction. When a light source that emits light pulses is used in a scan exposure method, it is possible to provide an accurate exposure amount for each point in a shot area on a substrate.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a schematic configuration of a projection exposure apparatus suitable for one embodiment of the present invention. Illumination light I emitted from light source 1
L passes through the shutter 2 and is adjusted to a predetermined light beam diameter by a lens system 4 including a collimator lens and the like, and then enters a fly-eye lens 6 via a mirror 5. Illumination light I
L is, for example, an excimer laser beam of KrF or ArF, a harmonic of a copper vapor laser or a YAG laser, or a bright line in the ultraviolet region of an ultra-high pressure mercury lamp. The shutter 2 can be inserted into and removed from the optical path by a shutter driving unit 3, and controls opening and closing of the optical path. However, when the light source 1 is a pulse light source such as an excimer laser, it is unnecessary to use the shutter 2 for controlling the light amount. is there.

Light rays emitted from the fly-eye lens 6 are incident on a reticle (mask) R on which a semiconductor circuit pattern or the like is drawn via relay lenses 7a and 7b, a reticle blind 8, a mirror 9, and a condenser lens 10. The combined system of the fly-eye lens 6, the relay lenses 7a and 7b, the mirror 9, and the condenser lens 10 illuminates the illumination light I emitted from each lens element of the fly-eye lens 6.
L is superimposed on the reticle R to illuminate the reticle R with uniform light intensity. The light-shielding surface of the reticle blind 8 has a conjugate relationship with the pattern area of the reticle R, and a plurality of movable light-shielding portions (for example, two L-shaped movable light-shielding portions) constituting the reticle blind 8 are connected to the motor 1.
The size (slit width, etc.) of the opening is adjusted by opening and closing by step 1. The illumination area IA for illuminating the reticle R is arbitrarily set by adjusting the size of the opening. The reticle R is vacuum-sucked on a reticle stage RST provided on the base 12, and the reticle stage RST is moved in a plane perpendicular to the optical axis IX of the illumination system.
Can be finely moved in a two-dimensional direction on the base 12 via an air bearing or the like in order to determine the position. The reticle stage RST can be moved on the base 12 in a predetermined direction (scan direction) by a reticle driving unit 13 constituted by a linear motor or the like. Reticle stage R
ST indicates that the entire surface of the reticle R has at least the optical axis IX of the illumination system.
Have a travel stroke sufficient to cross the A movable mirror 15 for reflecting the laser beam from the interferometer 14 is fixed to an end of the reticle stage RST, and the position of the reticle stage RST in the scanning direction is constantly set by the interferometer 14 at a resolution of, for example, about 0.01 μm. Is detected. Reticle stage R from interferometer 14
The position information of the ST is sent to the reticle stage control system 16, and the reticle stage control system 16
The reticle driving unit 13 is controlled based on the position information of the ST to move the reticle stage RST. The reticle stage RS is positioned so that the reticle R is accurately positioned at a predetermined reference position by a reticle alignment system (not shown).
Since the initial position of T is determined, the position of the reticle R is measured with sufficiently high accuracy only by measuring the position of the movable mirror 15 with the interferometer 14.

The illumination light IL that has passed through the reticle R
Is incident on, for example, a projection optical system PL that is telecentric on both sides. The projection optical system PL applies a resist (photosensitive agent) on the surface of a projected image obtained by reducing the circuit pattern of the reticle R to, for example, 1/5 or 1/4. Formed on the wafer W.

In the exposure apparatus according to this embodiment, FIG.
Reticle side scanning direction (+ x direction) as shown in
The reticle R is illuminated in a rectangular (slit-shaped) illumination area IA having a longitudinal direction perpendicular to the reticle R, and the reticle R is scanned at the speed of the arrow Vr during exposure. The illumination area IA (the center substantially coincides with the optical axis IX) is projected onto the wafer W via the projection optical system PL, and the projection area I
A 'is formed. Since the wafer W has an inverted image relationship with the reticle R, the direction is opposite to the direction of the arrow Vr (−x direction).
Then, scanning is performed at a speed indicated by an arrow Vw in synchronization with the reticle R, and the entire shot area SA of the wafer can be exposed. The scanning speed ratio Vw / Vr accurately corresponds to the reduction magnification of the projection optical system PL, and the pattern of the pattern area PA of the reticle R is accurately reduced and transferred onto the shot area SA on the wafer W. You. Illumination area IA
Is formed so as to be longer than the pattern area PA on the reticle R and smaller than the maximum width of the light shielding area ST.
A enables illumination of the entire surface.

Referring back to FIG. 1, the wafer W is vacuum-sucked on the wafer holder 17 and is held on the wafer stage WST via the wafer holder 17. The wafer holder 17 can be tilted in an arbitrary direction with respect to the best image forming plane of the projection optical system PL by a driving unit (not shown), and the optical axis IX
Fine movement is possible in the direction (Z direction). The wafer stage WST is configured to be movable not only in the above-described scan direction (X direction) but also in a direction (Y direction) perpendicular to the scan direction so as to be able to move arbitrarily to a plurality of shot areas. Then, a step-and-scan operation is performed in which the operation of scanning and exposing each shot area on the wafer W and the operation of moving to the next shot exposure start position are repeated. The wafer stage driving unit 18 such as a motor moves the wafer stage WST in the XY directions. Wafer stage WS
A movable mirror 20 that reflects the laser beam from the interferometer 19 is fixed to an end of T, and the position of the wafer stage WST in the XY directions is set to, for example, 0.01 by the interferometer 19.
It is always detected with a resolution of about μm. Wafer stage W
The ST position information (or speed information) is sent to the wafer stage control unit 21, and the wafer stage control unit 21 controls the wafer stage driving unit 18 based on the position information (or speed information).

Although not described in detail, the wafer W which has been exposed last time by a wafer alignment system (not shown) and has been processed so that the projected image of the reticle is accurately superposed and exposed. In the apparatus shown in FIG. 1, an image forming light beam for forming a pinhole or a slit image toward the best image forming plane of the projection optical system PL is inclined obliquely to the optical axis IX direction. An irradiation optical system 22 supplied from a light receiving optical system 23 for receiving, via a slit, a light beam reflected by the surface of the wafer W of the image forming light beam.
The oblique incidence type wafer position detection system (focus detection system) composed of
It is fixed to. The configuration and the like of this wafer position detection system are disclosed in, for example, Japanese Patent Application Laid-Open No. 60-168112.
Direction), the wafer W and the projection optical system PL are detected.
Are used to drive the wafer holder 17 in the Z direction so as to keep a predetermined interval. The wafer position information from the wafer position detection system is input to the focus position control unit 25, and the wafer position information is sent to the wafer stage control unit 21 via the main control system 100. The wafer stage controller 21 drives the wafer holder 17 in the Z direction based on the wafer position information.

In this embodiment, the angle of a parallel plate glass (not shown) provided beforehand inside the light receiving optical system 22 is adjusted so that the image plane becomes the zero point reference, and the wafer position is detected. System calibration shall be performed. Further, for example, Japanese Patent Application Laid-Open No. 58-113706
A horizontal position detection system as disclosed in Japanese Patent Application Laid-Open Publication No. H10-207, or a wafer position detection system is configured to detect a focus position at any of a plurality of positions in the image field of the projection optical system PL (for example, By forming a plurality of slit images in the image field), the inclination of a predetermined region on the wafer W with respect to the image plane may be detected.

On the wafer stage WST, an irradiation amount sensor 41 is provided at a height substantially equal to the height of the surface of the wafer W. The irradiation amount sensor 41 has a light receiving surface at least equal to or larger than the projection area IA ′, and is moved to a position immediately below the optical axis IX of the projection optical system PL during measurement, so that the reticle R
And outputs a signal Sc corresponding to the intensity of the entire illumination light passing therethrough. This is used for initial setting at the time of correcting an imaging characteristic that fluctuates with the incidence of illumination light, as described in detail later.

Here, a detailed arrangement example of the interferometer 19 will be described with reference to FIG. FIG. 3 shows the wafer stage WS
It is a detailed view around T. The interferometer 19 of this embodiment includes an X interferometer (interferometer 19x ₁ , interferometer 19x ₂ ) and a Y interferometer (interferometer 19y ₁ , interferometer 19y) for measuring a position in the X direction.
₂ ) and an interferometer 19ya for alignment having an optical axis in the Y direction passing through the center OAc of the observation area OA of the off-axis alignment system (not shown). The interferometers 19x ₁ and 19x ₂ are arranged symmetrically with respect to a straight line Cx that passes through the center Ce of the projection field if of the projection optical system PL and is parallel to the X axis. The moving mirror 20x is an interferometer 19
This is a movable mirror for detecting the position in the X direction that reflects the laser light from x ₁ and 19x ₂ . The interferometers 19y ₁ and 19y ₂ are arranged symmetrically with respect to a straight line Cy passing through the center Ce of the projection field if of the projection optical system PL and parallel to the Y axis. Moving mirror 2
Reference numeral 0y denotes a moving mirror for detecting the position in the X direction that reflects the laser beams from the interferometers 19y ₁ and 19y ₂ . The wafer stage controller 21 includes a position calculator 21Xe for calculating a position in the X direction, and a yawing calculator 21Xθ, Y for obtaining a yawing amount from the Y axis of the movable mirror 20x (stage WST).
Position calculating unit 21Ye for calculating the position in the direction, movable mirror 20
A yawing calculation unit 21Yθ for calculating a yawing amount of the y (stage WST) from the X axis, and a position calculation unit 21Ya for calculating a position in the Y direction at the center OAc of the off-axis alignment system are provided. Position calculation unit 21
Xe calculates the position measurements Xe in the X direction of the wafer stage WST from the average of the measurement values of interferometers 19x ₂ and the measurement value of the interferometer 19x _1. Yawing calculator 21Xθ calculates the yawing amount Xθ in moving in the X direction of the wafer stage WST from the measurement value of the measurement values and the interferometer 19x ₂ interferometers 19x _1. The position calculator 21Ye is the interferometer 1
Calculates the position measurements Ye in the Y direction of the wafer stage WST from the average of the measurement values of 9y ₁ and the measured value of the interferometer 19y _2. Yawing calculator 21Yθ calculates the yawing amount Yθ in movement in the Y direction of the wafer stage WST from the difference between the measured values of the interferometer 19y ₂ and the measurement value of the interferometer 19y _1.

The position calculating section 21Ya is for measuring the position Ya of the wafer stage WST in the Y direction when detecting a mark on the wafer W in the off-axis alignment system. Position measurement system for alignment (interferometer 19
ya, the position detection unit 21Ya) is provided because Abbe error at the time of mark detection caused by the distance between the observation center OAc of the off-axis alignment system and the center Ce of the projection visual field if of the projection optical system PL in the x direction. This is to prevent The wafer stage WST is provided with a reference plate FM on which reference marks are formed.
Is used to measure the distance (base line) between the observation center OAc of the off-axis alignment system and the center Ce of the projection field if of the projection optical system PL. The surface of the reference plate FM has a reflective surface R ₃ of substantially zero reflectivity and reflective surface R ₂ having a reflectivity r _2, reflective surface R ₁ surface of the radiation amount sensor 41 having a reflectivity r ₁ have. Each reflecting surface calculates the offset component as described later,
Used as a reference reflecting surface for calculating the reflectivity of the wafer.

By the way, as shown in FIG.
The yawing amount of ST is measured independently using both the x-axis movable mirror 20x and the y-axis movable mirror 20y,
This is because the averaging circuit 21k averages the values of the yawing amounts Xθ and Yθ measured in both of them. In this way, since the variation in the interferometer 19x _1, 19x interferometer for ₂ and Y axis 19y _1, 19y measurements by air fluctuations in the laser beam path of the _second X-axis are averaged, and more A highly reliable yawing amount can be measured.

In the case of the stage WST for wafer exposure as shown in FIG. 3, there is not much problem. Depending on the arrangement (pattern arrangement), it may become extremely large in one of the x direction and the y direction. In this case, on the side where the moving stroke is extremely large, one laser light path of the pair of interferometers for yawing measurement may protrude from the moving mirror near the end point of the stroke. Therefore, whether the laser beam path protrudes from the movable mirror on the X-axis side or the Y-axis side based on the pattern arrangement on the glass plate (which is known in advance by design before exposure) is examined, and the interferometer of the axis that does not protrude May be switched so as to use the yawing amount measured in step (1). Of course, when the laser beam does not protrude from the laser beam paths of the interferometers on both axes, it is needless to say that it is desirable to use the average yawing amount from the averaging circuit 21k.

In the optical path between the fly-eye lens 6 and the reticle R of the apparatus shown in FIG. 1, a part of the illumination light IL (for example, 5% light) is reflected and the remaining light is transmitted. A beam splitter 26 is provided to guide reflected light from the reticle R to a reflected light sensor 27. The reflected light sensor 27 uses a photoelectric sensor such as a silicon photodiode or a photomultiplier, receives reflected light from the wafer W via the reticle R, and outputs a signal Sb to the main control system 100. The reflected light sensor 27 is in the illumination area I
Since it is desirable to receive the entire reflected light within A (IA ′), the light may be condensed by a lens or the like or provided on a Fourier transform plane with respect to the wafer W, that is, a position conjugate with the pupil position of the projection lens PL. desirable.

The beam splitter 26 guides a part of the illumination light from the light source 1 to a photoelectric sensor 28 for detecting the light intensity of the light beam from the light source 1. The photoelectric sensor 28 receives a part of the illumination light IL reflected by the beam splitter 26 and outputs an output signal Sa to the main control system 100.
The functions of the reflected light sensor 27 and the photoelectric sensor 28 will be described later in detail.

The apparatus is provided with input means 101 such as a keyboard and a bar code reader. The input means 101 includes information on a thermal time constant of a projection optical system, information on transmittance of a reticle R, a value of an illumination slit width, Various information such as a target exposure amount and a scan speed can be input.

The exit end face of the fly-eye lens 6 on which a plurality of secondary light source images are formed has a Fourier transform relationship with the pattern area of the reticle R.
An aperture 29 for changing the shape of the next light source is provided so as to be replaceable. The diaphragm 29 restricts the shape of the secondary light source image to a ring shape, the diaphragm restricts the shape of the secondary light source image to a plurality of discrete areas eccentric from the optical axis IX, and the diaphragm 29 for the secondary light source image. A circular diaphragm or the like whose size is variable without changing its center.
A ring-shaped stop is disclosed in JP-A-61-91662 and the like. As a stop for limiting the shape of a secondary light source image, for example, four apertures are arranged point-symmetrically with respect to the optical axis IX. And is as disclosed in detail in JP-A-4-225514 and the like.

The apparatus shown in FIG. 1 has a projection optical system PL.
A correction mechanism capable of correcting the imaging characteristics is provided. Hereinafter, the correction mechanism for the imaging characteristics will be described.

As shown in FIG. 1, in this embodiment, the reticle R or the lens element 3 is controlled by the imaging characteristic controller 30.
By driving each of 4 and 35 independently, it is possible to correct the optical characteristics of the projection optical system PL itself and the imaging characteristics of the projected image. The reticle stage RST can be finely moved by the driving element 31 in the optical axis IX direction (vertical direction). Piezoelectric elements, electrostrictive elements, air dampers and the like are used as the driving elements 31, and three or four driving elements 31 are used to drive the entire reticle stage RST.

The terms of the imaging characteristics of the projection optical system PL include a focus position (image plane position), projection magnification, distortion, field curvature, astigmatism, etc., and these values are individually corrected. It is possible. However, in this embodiment, in order to simplify the description, an example of a method of driving the lens element of the projection optical system PL particularly in the case of correcting the focal position, the projection magnification, and the field curvature in the projection optical system which is telecentric on both sides. This will be explained.

The first group of lens elements 34 closest to the reticle is fixed to a support member 36, and the second group of lens elements 35 is fixed to a support member 37. The lens element below the lens element 38 is fixed to the lens barrel 39 of the projection optical system PL. In this embodiment, the optical axis IX of the projection optical system PL is the lens barrel 39.
Is the optical axis of the lens element fixed to the lens element.

A plurality of support members 36 (for example, 3
(Two of them are shown in FIG. 1) are connected to the support member 37 by a drive element 32, and the support member 37 is connected to the lens barrel 39 by a plurality of expandable and contractible drive elements 33.

Here, when each of the lens elements 34 and 35 is moved in parallel in the optical axis direction, the projection magnification (the amount of enlargement or reduction of the size of the projected image) is obtained at a change rate corresponding to the amount of movement.
Each of M, field curvature C and focal position F changes by a small amount. Assuming that the driving amount of the lens element 34 is z ₁ and the driving amount of the lens element 35 is z ₂ , each of the projection magnification M, the field curvature C, and the amounts of change ΔM, ΔC, and ΔF of the focal position F are expressed by the following equations. Is done.

ΔM = C _M1 × z ₁ + C _M2 × z ₂ (1) ΔC = C _C1 × z ₁ + C _C2 × z ₂ (2) ΔF = C _F1 × z ₁ + C _F2 × z ₂ (3) _Here , C _M1 , C _M2 , C _C1 , C _C2 , C _F1 , and C _F2 are constants representing the rate of change of each change amount with respect to the drive amount of the lens element.

As described above, the wafer position detection systems 22 and 23 detect the amount of deviation of the wafer surface from the optimum focus position with the optimum focus position of the projection optical system PL as a zero point reference. Therefore, the wafer position detection systems 22, 2
Electrically or optically appropriate offset z _{3 with} respect to ₃
Is given, by using the wafer position detection systems 22 and 23 to position the wafer surface, it is possible to correct the focal position shift accompanying the driving of the lens elements 34 and 35. At this time, the above equation (3) is expressed as the following equation.

ΔF = C _F1 × z ₁ + C _F2 × z ₂ + z ₃ (4) From the above, the driving amounts z _{1 to} z ₃ are set in the equations (1), (2) and (4). The amount of change Δ
M, ΔC, and ΔF can be arbitrarily corrected. In addition,
Here, the case where the three types of imaging characteristics are corrected simultaneously has been described. It is not necessary to perform the above-described correction, and when the imaging characteristics other than the three types described in the present embodiment change significantly, it is necessary to correct the imaging characteristics. In this embodiment, since the amount of change in the curvature of field is corrected to zero or less than an allowable value, correction of astigmatism is not particularly performed.

In this embodiment, the change amount ΔF of the focal position
For (Equation (4)), for example, the wafer position detection system 2
The change amount ΔF is electrically or optically (plane-parallel) offset applied to the wafers 2 and 23, and the wafer W is moved in the Z direction by using the wafer position detection systems 22 and 23, so that the projection optical system is used. It is assumed that the surface of the wafer W is set at the best imaging plane (best focus position) of the system PL.

Here, in this embodiment, the imaging characteristic control unit 30
Reticle R and lens elements 34 and 35
Is movable in the direction of the optical axis. In particular, the lens elements 34 and 35 are more easily controlled with greater influence on characteristics such as magnification, distortion, and field curvature (astigmatism) than other lens elements. Has become. Also,
In this embodiment, two groups of movable lens elements are used. However, three or more groups can be used. In this case, the range of movement of the lens elements can be increased while suppressing fluctuations of other aberrations. It is possible to deal with distortion (trapezoidal and rhombic distortion) and field curvature (astigmatism). Also, distortion or the like can be corrected by Z driving of the reticle R.

Further, feedback control is performed to a predetermined control target position by using together with a position sensor for monitoring the driving amount, for example, an encoder, a capacitance type sensor, a light reflection type sensor or the like. Also, even if dynamic correction is not performed during the exposure operation (during operation), if it is used only for maintenance work, it can be replaced with a fine feed mechanism with a micrometer head or a semi-fixed mechanism with a washer. is there.

As described above, the reticle R
Although an example of correcting by moving the element has been described, a suitable correction mechanism in the present embodiment may be any other method, for example, sealing a space between two lens elements or a parallel plate glass, A method of adjusting the pressure in the sealed space may be adopted. The apparatus of FIG. 1 is provided with a pressure control system 40 for adjusting the pressure in the sealed space sandwiched between the lens elements and correcting the optical characteristics (particularly magnification) of the projection optical system PL itself by a small amount. The pressure control system 40 is also controlled by the imaging characteristic control unit 30 so as to give a desired imaging characteristic to the projected image. The detailed configuration of the pressure control system 40 is disclosed in Japanese Patent Application Laid-Open No. Sho 60-78416, and the description thereof is omitted here.

As described above, by adopting the correction mechanism configured to drive the lens elements and adjust the pressure in the sealed space between the end elements, the fluctuation of the imaging characteristics of the projection optical system PL due to the absorption of exposure light. Can be adequately dealt with.

Next, a method for calculating the amount of change in the imaging characteristics due to absorption of exposure light will be described. Based on the calculated amount of change in the image formation characteristics, the above-mentioned image forming characteristic correction mechanism is optimally driven. Will be. Strictly speaking, the calculation of the fluctuation amount needs to be individually calculated for each of the above-described imaging characteristics. This is because the degree of influence on each imaging characteristic is slightly different depending on the lens element constituting the projection optical system PL, and therefore, even if illumination light having the same energy is incident on the projection optical system PL, the fluctuation characteristics are different. . However, since the basic calculation method is exactly the same, and the coefficients are slightly different, for the sake of simplicity, the following description will be made using the change ΔM of the projection magnification as an example.

First, the principle will be described. The change ΔM in the projection magnification occurs because the lens element inside the projection optical system PL slightly absorbs the illumination light and the temperature rises, so that the refractive index or the curvature of the lens element slightly changes. Focusing on one lens element now, the lens element has energy input by illumination light, that is, absorption of heat quantity and emission of heat quantity escaping to the external lens barrel 39 and the like. Is determined. Assuming that the temperature rise and the magnification change ΔM are in a proportional relationship, it is considered that the magnification change ΔM is determined by the balance between the two. In general, when the temperature rise of the lens element is low, the absorption of heat exceeds the release and the temperature gradually rises. When they are balanced, they are in equilibrium with the saturation level. When the exposure operation that has been performed up to that time is stopped, the amount of heat is gradually released, and the temperature of the lens element decreases. However, when the temperature difference from the ambient temperature decreases, the speed of heat release slows down. This characteristic is generally called first-order lag, and can be expressed by a first-order differential equation. This is shown in FIG. FIG.
4A shows incident energy, and FIG. 4B shows a magnification change characteristic when illumination light having a constant energy amount is irradiated on the projection optical system PL for a predetermined time. The change characteristic shown in FIG. 4B is the final change amount ΔM ₁ (saturation level) of the projection magnification with respect to the irradiation energy E ₁ , and the change rate ΔM
_It can be determined by two values of ₁ / E ₁ and a time constant T representing a temporal change. In FIG. 4, the time constant T is the final variation Δ
It can be defined as the time that varies by ^{_{ΔM 1 × (1-e -1}} ) with respect to M _1. Here, if the change rate ΔM ₁ / E ₁ and the time constant T are obtained, it is possible to calculate the magnification change ΔM from the estimated value of the energy E incident on the projection optical system PL based on the output Sa of the photoelectric sensor 28. Specifically, it is obtained by constantly monitoring the incident energy E and sequentially calculating ΔM inside the main control system 100 based on the change rate ΔM ₁ / E ₁ and the time constant T. The change rate ΔM ₁ / E ₁ and the time constant T can be obtained by experimentally irradiating the projection optical system PL with illumination light and confirming the characteristics as shown in FIG. 4B. However, since a plurality of lens elements actually exist in the projection optical system PL, the overall magnification variation characteristic is expressed in the form of the sum of some primary delay characteristics. Change rate ΔM
₁ / E ₁ and the time constant T are input to the main control system 100 by the input means 101 in advance. As described above, the change rate ΔM ₁ / E
₁ and the time constant T are coefficients of a first-order differential equation, and this differential equation is usually solved sequentially by numerical analysis such as digital calculation. If the calculation synchronization at this time is set to a predetermined time which is sufficiently shorter than the time constant T, and the value of the energy E incident on the projection optical system PL is calculated every moment according to the calculation synchronization (calculation), the main control system With 100, the change amount ΔM at that time can be calculated.

Next, a description will be given of a method for obtaining the incident energy E different according to the position of the reticle and obtaining the fluctuation characteristics of the imaging characteristics when the energy amount is different during one-shot exposure.

Hereinafter, a method of obtaining the energy E which is incident on the projection optical system PL moment by moment will be described. When considering the incident energy on the projection optical system PL, it is necessary to consider not only the amount of light incident through the reticle but also the amount of light reflected by the wafer and incident again on the projection optical system. In the case of the scan type, since the reticle R is scanned with respect to the slit-shaped illumination area IA, the total area of the light-shielding portion of the reticle R appearing in the illumination area IA changes sequentially according to the scanning position of the reticle R. The incident energy E to the projection optical system PL changes according to the reticle scan position. Therefore, for example, during scanning exposure,
The sum of the amount of light incident on the projection optical system PL via the reticle and the amount of light reflected on the wafer and incident again on the projection optical system PL is obtained for each sampling time of the time interval Δt of ec,
The incident energy E may be calculated.

At this time, the projection optical system PL is connected via a reticle.
Is obtained based on the output Sa of the photoelectric sensor 28, and the amount of light reflected by the wafer and incident again is obtained based on the output Sb of the reflected light sensor. However, the output Sb of the reflected light sensor 27 includes the light amount information of the light reflected by the reticle R and the optical member in the illumination optical system. Therefore, in this embodiment, reference reflection data for obtaining the reflection intensity of the wafer is obtained according to the scanning position of the reticle by using reference reflection plates having different known reflectances from each other. The reflectance (reflection intensity) of the wafer was determined according to the scanning position of the reticle. The transmittance (light transmission amount) of the reticle is also determined according to the scan position of the reticle, and the energy E is determined based on such information.

A method for calculating the incident energy E using the wafer reflectivity obtained based on the reference reflection data and the reticle transmittance will be described below. Assuming that the amount of light incident on the projection optical system PL via the reticle R is P and the reflectance of the wafer W is r, the total amount of incident light on the projection optical system PL is reflected by the wafer W and enters the projection optical system PL. Reflected light amount P
-It can be expressed as in equation (5) including r.

E = P × (1 + r) (5) The amount of light P can be obtained by setting the transmittance of the reticle R at the irradiation position to η, the illuminance of the light source per unit area to Ip, and the irradiation area to S. Then, it can be expressed by the following equation.

P = Ip × S × η (6) Here, for convenience, the illuminance Ip is the illuminance per unit area on the wafer W surface (illuminance without a reticle), and S is the wafer W
However, since the relationship between ΔM and E only needs to be finally determined, the light amount P may be defined on the reticle R or may be defined elsewhere. No problem.

When performing scan-type exposure, the amount of light incident on the projection optical system PL via the reticle differs depending on the position of the reticle R. Therefore, the reticle transmittance η needs to be obtained for each reticle R scanning position. Hereinafter, a method for obtaining the reticle transmittance will be described.

After moving the wafer stage WST so that the irradiation amount sensor 41 is located within the irradiation area IA ',
With the wafer stage WST fixed, only the reticle stage RST is scanned while the reticle R is mounted, and the magnitude of the output Sc ₁ of the irradiation amount sensor 41 at that time is measured by the reticle interferometer 14 for measuring the position of the reticle stage RST. Read sequentially in accordance with the position coordinates (x _R ),
At the same time, the magnitude of the output Sa of the photoelectric sensor 28 is read. Then, the ratio Sc ₁ / Sa is calculated and the main control system 10
0 is stored in the memory corresponding to the coordinate position. The timing of storage in the memory (digital sampling) is, for example, the resolution of the reticle interferometer 14 (for example, 0.01 μm).
With a constant moving amount (for example, 0.01 μm to 10 μm)
(every μm). Since the main control system 100 is usually constituted by a digital computer, the main control system 100 is sequentially calculated with the resolution of the interferometer 14 at each position interval (or time interval) where an error in the calculation accuracy of the magnification variation does not matter. Some of the digital values of the ratio Sc ₁ / Sa may be averaged and stored, or the values may be sequentially calculated at about the resolution of the interferometer 14 (or a constant moving amount coarser than that). The ratio Sc ₁ / Sa may be stored as it is.

The position at which movement of reticle stage RST to read output Sc ₁ is stored in main control system 100 as a reference position for reading. The output Sc ₂ of the irradiation amount sensor 41, the reticle transmittance data η (x _R ), the output Sb of the reflected light sensor 27, the reference reflectance data rx (x _R ), and the data of the offset component, which will be described later, are stored in the memory. All measurements are made based on this position.

Next, reticle R is moved to reticle stage RST.
Before mounting on the sensor, a ratio Sc ₂ / Sa ′ (a constant value independent of the scanning position) between the output Sc ₂ of the irradiation amount sensor 41 and the output Sa ′ of the photoelectric sensor 28 detected at the same timing is determined in advance. Using the value of the ratio Sc ₂ / Sa ′ as the denominator,
Data sequence (waveform) of ratio Sc ₁ / Sa stored in memory
Is standardized (divided). Thereby, the ratio Sc ₁ · Sa ′ of the output of the irradiation amount sensor 41 depending on the presence or absence of the reticle R
The data sequence of / Sc ₂ · Sa is obtained, and the data sequence of this ratio is stored in the memory at the same interval as the digital sampling interval of the output Sc ₁ . This output ratio Sc ₁ · Sa ′ /
Sc ₂ · Sa is the true reticle transmittance η corrected for the detection error due to the fluctuation of the illuminance Ip, and the transmittance η is the position x _R
Η (x _R ), and can be represented by a curve as shown in FIG. 5 as an example. The horizontal axis in FIG. 5 indicates the position x _R of the X direction of the reticle (scanning direction) and the vertical axis represents the reticle transmittance eta. Position x _R from the during scanning varies with time t, if the scan is performed at a constant speed,
η (x _R ) = η (t). Since the illuminance Ip is an element that varies with time, at the time of actual scan exposure, the above equation (6) is used as the equation (7), and the illuminance IP during the scan exposure is sequentially obtained from the output Sa of the photoelectric sensor 28 to obtain the equation (6). 7).

P (t) = S × η (t) × Ip (t) (7) η (t) = η (x _R ) When the illuminance Ip does not change with time, for example, a mercury discharge lamp or the like is used as a light source. Then, since the fluctuation of the illuminance Ip during the exposure of the one-shot area on the wafer W can be almost ignored, the illuminance Ip is detected and stored by the output Sa of the photoelectric sensor 28 immediately before the start of the scanning exposure, and is stored in the equation (7). Ip during calculation
(T) can be treated as a constant. At this time, the shutter ON / OFF signal indicates that when the shutter is ON, Ip
Can be treated as a constant value, and when the shutter is off, it can be treated as Ip = 0. Further, since the output of the irradiation amount sensor 41 directly represents P (t), P (t) measured before exposure is used even if η (t) is not registered in advance for each reticle. You can also. In any case, since the time t in the equation (7) uniquely corresponds to the scan position of the reticle (or wafer), the reticle interferometer 1
The transmittance data η (x _R ) is read from the memory in accordance with the measurement position x _R of No. 4, and the incident light amount P (t) is obtained in real time.

Further, since the irradiation amount sensor 41 may have a smaller light receiving area as compared with the simultaneous exposure type in which the entire surface of the reticle is illuminated at once, an inexpensive and uniform sensor having almost no illuminance unevenness in the light receiving surface ( Silicon photodiode) can be used. Further, when the light source 1 is a pulse light source, the irradiation amount sensor 41 receives the pulse light. At this time, the intensity is measured for each pulse triggered in accordance with the scanning position of the reticle R, and the output is measured. Sc may be sequentially taken in as illuminance Ip,
For example, the intensity of the pulsed light (single or multiple pulses) triggered during several to several tens of mSec may be integrated, and sequentially acquired as the average illuminance Ip within that time.

Next, a method of obtaining the reflectance r in the equation (5) will be described.

As described above, not only the reflected light from the wafer W surface but also the reflected light from the reticle R surface or each lens element of the projection optical system PL enters the reflected light sensor 27. Therefore, the actual wafer reflectance is calculated by calculation in accordance with reference reflection data created using a reference reflection surface on wafer stage WST in advance. Here, the surface of the radiation amount sensor 41 and the reflective surface R ₁ of known reflectance r _1, the surface of the reference plate FM and the reflective surface R ₂ of known reflectivity r _2. The reflectances r ₁ , r ₂ (r ₁ > 0, r ₂ > 0) of the _two reference reflecting surfaces with respect to the illumination light for exposure are known values measured in advance, and the two reflectances r ₁ , r _Two
Should be very different. In first state where the reticle R is set, after the reflecting surface R ₁ in the projected exposure area IA 'moves the wafer stage WST to be positioned, a predetermined reticle stage RST while stopping the wafer stage WST By moving at a speed, the magnitude of the output I ₁ of the reflected light sensor 27 is digitally sampled for each scanning position of the reticle R, and sequentially stored in the memory of the main control system 100 in association with the scanning position. The timing of digital sampling and storage in the memory may be performed, for example, every fixed movement amount with reference to the resolution (eg, 0.01 μm) of the reticle interferometer 14. Also in this case, the digital sampling interval does not need to coincide with the resolution of the interferometer 14, and may be coarse, for example, every 0.2 μm to 10 μm.

Next, after moving wafer stage WST such that reflection surface R ₂ having reflectance r ₂ is located within irradiation area IA ′, reticle stage RST is moved at a predetermined speed while wafer stage WST is stopped. Then, the magnitude of the output I ₂ of the reflected light sensor 27 is sequentially stored (digitally sampled) in the memory of the main control system 100 according to the position of the reticle R. In this case the timing of storage in the memory is the same as the interval of the digital sampling of the output I _1,
Address on the memory is also a sampling position of the output I ₁ and the sampling position of the output I ₂ is set to to correspond uniquely related.

In particular, when the light source 1 is a pulse light source, the values of the outputs I ₁ and I ₂ are normalized (I ₁ / Sa) to correct the intensity variation for each pulse by using the output Sa of the photoelectric sensor 28. , I ₂ / Sa). This can be similarly applied to the case where the bright line of the mercury discharge lamp is used as the illumination light, and the standardized values I ₁ / Sa and I ₂ / Sa are stored in the memory.

FIG. 6 shows the relationship between the output of the reflected light from the reference reflecting surface and the reflectance. FIG. 6 shows a reticle R 1
Values I ₁ ,
The vertical axis represents I ₂ (or I ₁ / Sa, I ₂ / Sa), and the horizontal axis represents the reflectance. As shown in FIG.
_1, I _1), the draw a straight line through the (r _2, I _2), the reflectance of the wafer from the output value of the reflected light sensor 27 obtained at scanning position (precisely reflection intensity) rx is obtained.
That is, assuming that the output of the reflected light sensor 27 when the reticle R reaches the scanning position during the actual exposure is Ix, the wafer reflectance rx at this time is the reference reflection data in the memory corresponding to the scanning position. Read I ₁ and I ₂ ,
rx = [(r ₂ −r ₁ ) / (I ₂ −I ₁ )] × (Ix
−I ₁ ) + r ₁ (8) In addition, using three reference reflection surfaces having different reflectances from each other,
A method such as obtaining the straight line in FIG. 6 from three measurement points by least squares approximation may be used. Also in this case, the area of the reference reflection surface can be smaller than that of the collective type. When receiving the pulsed light, the reflected light sensor 27 may measure the intensity for each pulse, or may integrate a power for a short period of time, for example, several to several tens of mSec, and output it as an average power. Good.
In any case, the outputs I ₁ and I ₂ are stored in the memory before the actual exposure.
Or the equation (8) is created as reference reflection data for each device position (sampling position) of the reticle R, and is stored in the memory. When the output I ₁ I ₂ is normalized by the output Sa, the output Ix of the reflected light sensor 27 when determining the actual wafer reflectance rx is also the output Sx.
It goes without saying that the value is normalized by a and then substituted into equation (8).

Here, the light reflected by the reference reflecting surface
Output I of reflected light sensor 27 for each scanning position of the tickle
₁(X_R), I_Two(X_RReference reflection data created as)
Of the reticle of the reflected light from the wafer W during the actual exposure.
The output Ix (x_R) Example
As shown in FIG. The vertical axis in FIG. 7A is the intensity I of the reflected light.
x indicates the position of the reticle in the X direction._RIndicates that
Scanning of reticle R is at position _R1To x_R2Done over
Shall be. Then, for example, the first show on the wafer W
Ix of the reflected light sensor 27 during the actual exposure of the cut area
(X_R) And the previously stored I
₁(X_R), I_Two(X_R) Data and fixed constant r₁, R
_TwoThe reflectance data according to the reticle scanning position.
Tarx (x_R) Is based on equation (9) based on equation (8) above.
Is calculated. The reflectance data rx (x_R) Is the output I
₁(X_R), I_Two(X_R) Digital sampling interval
At the same sampling interval as above and uniquely with the scanning position
It is stored in the memory at the corresponding address. Reticle position
Reflectance data rx (x_R) Is shown in FIG.
You. In FIG. 7B, the vertical axis represents the wafer reflectance, and the horizontal axis represents the laser reflectance.
Scanning position x in the X direction of the tickle_RIs shown.

Rx (x _R ) = [(r ₂ −r ₁ ) / (I ₂ (x _R ) −I ₁ (x _R ))] × (Ix (x _R ) −I ₁ (x _R )) + r ₁ ... (9) for the position x _R is vary with time, the reticle stage RST in the actual exposure Assuming that the constant speed movement, reflectance data rx (x _R) is replaced by the rx (t),
The formula (7) and the formula (9) are substituted into the formula (5) to obtain a predetermined time Δ
The energy value E (t) for each t is calculated by the main control system 100.

Next, the incident energy E to the projection optical system PL
And the calculation of the amount of change in the imaging characteristics of the projection optical system PL will be described with reference to FIG. Here, for the sake of simplicity, the magnification variation ΔM of the projection optical system PL will be described. FIG. 8A is a diagram showing the incident light amount E to the projection optical system PL. In the figure, Ea, Eb, and Ec indicate the energy incident on the projection optical system PL. In FIG. 8A, the instantaneous value or the average value of the incident energy at the position of the reticle stage RST within the predetermined time interval Δt (for example, several msec to several tens msec) is set as the incident energy E. In FIG. 8A, predetermined times (hereinafter referred to as “sampling times”) at predetermined time intervals Δt are denoted by t ₁ , t
₂ , t ₃ , t ₄ , and t _5, and the corresponding positions of the reticle stage RST are x ₁ , x ₂ , x ₃ , x ₄ , and x ₅ . The timing for starting the measurement of the sampling time starts when the reticle stage RST reaches the reference position at the time of storing the various data described above, and the positions x _{1 to} x ₅
Also, it is desirable to match the positions of the various data stored in the memory as much as possible. Of course, reticle stage RST is controlled to reach a predetermined speed before reaching the reference position.

The main control system 100 operates at the sampling time t.₁so
Reticle stage RST position x ₁Transmittance η at
(X₁) And the reflectance rx (x₁) And illuminance Ip (t₁) And c
Irradiation area of wafer W (irradiation determined by reticle blind 8)
Area) IA 'and equations (5), (7), (9)
Sampling time t₁Incident on the projection optical system PL at
Energy E (t₁) = Ea is calculated as an estimated value.
As described above, when the light source is a light source such as a mercury discharge lamp,
Opening / closing information of printer 2 (1 if open, 0 if closed)
Weight) and Ip = constant value, treating Ip (t) as a constant.
I can. Note that the transmittance η (x₁), Reflectance rx
(X₁X)₁Is the sampling time t₁
Does not correspond to the sampling time t₁Subsequent
The transmittance η (x stored at the nearest position x_R), Reflectance
rx (x_R) Should be used. Also, shutter
-2 opening / closing information (1 or 0)
If shutter 2 is open, equation (5),
The calculation according to (7) and (9) is executed, and E (t₁) = Ea
And when shutter 2 is closed, equation (5)
E (t) without performing the operations of (7) and (9)₁) = 0 and
May be used to

Hereinafter, the incident energy is similarly obtained for the sampling times t _{2 to} t ₅ . Here, the incident energy calculated at the sampling times t ₁ and t ₃ is E
a, Eb represents the incident energy calculated at the sampling times t ₂ and t ₅ , and Ec represents the incident energy calculated at the sampling time t ₄ .

The sampling time interval Δt (for example,
Sampling time t₁And t_TwoTime interval between)
To calculate the incident energy using the average value of
It may be. Specifically, for example, the aforementioned transmittance data
η (x_R), Reflectance data rx (x_R) Digital Sun
Set the spacing between the rings on the reticle every 25 μm, and
Ring time t₁And t_TwoSampling time interval Δ
t is 5 msec and scan speed V is 50 mm / sec.
Reticle during the sampling time interval Δt
The distance L at which the stage moves is L = V × Δt = 250 μm.
Become. Transmittance data η (x_R), Reflectance data rx (x
_RSince the digital sampling interval of ()) is every 25 μm,
Sampling time t₁And sampling time t_TwoBetween
10 sampling data within the sampling time interval Δt
Is the transmittance data η (x_R) And reflectance data rx (x
_R) And obtained for each. So, those 10
Of the transmission data η (x_R) And reflectivity rx
(X_R) And averaged data for each
Time t_TwoTransmittance data η (x_Two) And average anti
Emissivity rx (x_Two) May be used. And sump
Ring time t_TwoTransmittance η (x_Two) And the reflectance rx (x
_Two) And illuminance Ip (t_Two), Shutter 2 opening / closing information (open
(1 if closed, 0 if closed) and the wafer W
Surface of irradiation area (irradiation area determined by reticle blind 8)
Sampling based on the product and equations (5), (7) and (9)
Time t_TwoEnergy incident on projection optical system PL at
E (t _Two) = Eb is calculated as an estimated value. At this time,
If the light source 1 is a light source that emits pulsed light as described above,
The sampling time t₁And sampling time t_TwoWith
Unit time power within the sampling time interval Δt between
Are integrated and the result is averaged power Ip (t_Two)When
May be. Transmittance η (x_R) And the reflectance rx (x _R)of
Digital sampling interval is sampling time interval Δt
Smaller than the distance L that the reticle stage moves during
Resolution is required, and sampling time interval Δt is distance
L becomes smaller than the width of the illumination area IA in the scanning direction.
It is determined as follows.

The reflectance rx (x _R ) after one shot
May be obtained using the reflectance data rx (x _R ) stored in the memory at the time of one-shot exposure, without obtaining Eq. (9) based on Expression (9).

Next, the calculation of the amount of change in the optical characteristics of the projection optical system PL based on the amount of incident energy per unit time will be described with reference to FIG. ΔM in FIG. 8 (B)
s indicates a magnification change characteristic depending on the incident light amount E.
As shown in FIG. 8B, the magnification change characteristic with respect to the incident energy E is ΔM / E and the time constant T as shown in FIG.
Characteristics. Therefore, the magnification change amount corresponding to the incident energy at the position corresponding to each time (time at each predetermined time interval) is determined by ΔM / E and the time constant T as shown in FIG.
It is obtained from the magnification variation characteristic as described above.

A specific description will be given with reference to FIG.
The magnification change amount ΔM ₁ that changes between the sampling times t _{0 and} t ₁ depending on the energy Ea is obtained from the relationship of ΔM / E. The relationship of ΔM / E is obtained in advance by experiments and the like as described above. Similarly, the magnification change amount ΔM ₂ that changes between the sampling times t _{1 and} t ₂ depending on the energy Eb is obtained from the relationship of ΔM / E. Sampling time t ₁
Attenuation factor of magnification between ~t ₂ is defined by the time constant T thermal, time according to the time constant T from the initial value between the sampling times t ₁ ~t ₂ (in this case .DELTA.M ₁₎ Together with the amount of attenuation. Therefore, the magnification variation at the sampling time t ₂ is ΔM ₁ + ΔM ₂
Is the value obtained by subtracting the amount of attenuation between sampling times t _{1 and} t ₂ from the total value of. Similarly, the magnification fluctuation amount ΔM ₃ that changes between the sampling times t _{2 and} t ₃ by the energy Ea, and the sampling time t by the energy Ec
₃ magnification variation .DELTA.M ₄ which changes during ~t _4, the magnification variation .DELTA.M ₅ which changes during the sampling time t ₄ ~t ₅ by the energy Eb is determined from the relation .DELTA.M / E.
Then, similarly, the amount of attenuation between each sampling time is obtained, and the final magnification change amount at each sampling time can be obtained. FIG. 8B shows an envelope connecting the values at each sampling time as a variation characteristic of the magnification.
Can be obtained. Such a calculation method for gradually obtaining the magnification fluctuation characteristic from discrete magnification fluctuation values is disclosed in JP-A-60-78454 and JP-A-62-136821.

Next, a method of correcting the magnification will be described.

The imaging characteristic control unit 30 determines the control amount of the pressure control system 40 or the drive amount of the drive elements 31, 34, and 35 so as to change the magnification according to the magnification change characteristic shown in FIG. And correct the magnification. However, the imaging characteristic control unit 30 exclusively controls the projection magnification M in the direction perpendicular to the scan direction.
It is necessary to change the relative speed at the time of scanning the reticle R and the wafer W by a small amount with respect to the magnification in the scanning direction. Therefore, in order to change the size of the projected image isotropically over the entire surface of the shot area, the relative speed must be finely adjusted according to the magnification adjustment amount corrected by the imaging characteristic control unit 30.

The method of correcting a change in magnification has been described above, but other image forming characteristics can be similarly corrected. Note that a plurality of patterns of the reticle R are sequentially exposed on the wafer W. However, in order to increase productivity, the wafer stage WST (reticle stage RST) does not always scan in one direction, but scans every shot row on the wafer. Exposure may be performed while scanning alternately in the opposite direction. In other words, after exposing one shot row, there is a case where another shot row is exposed while scanning in the reverse direction (exposure while reciprocating). The above-described sampling of the transmittance data η, the reference reflectance data, and the like is performed by storing or calculating according to the position of the reticle R while moving the reticle in one direction (for example, the −x direction). Therefore, when the scan direction of wafer stage WST is alternately different in the opposite direction for each shot row of the wafer (when the scan direction of reticle stage RST is alternately different in the -x direction and the + x direction), transmission is performed according to the scan direction. The reading direction of the ratio data η and the reflectance data is switched. That is, when scanning is performed in a direction opposite to the scanning direction of the reticle stage RST in which the transmittance η and the reference reflectance data are stored, reading of the transmittance η, the reference reflectance data, and the like from the memory is performed in the reverse direction.

Here, it is also possible to obtain the average transmittance and the average reflectance during scanning and use the equations (5) and (6) as they are. This method is also one solution, but the accuracy deteriorates because the average transmittance and the average reflectance during one scan can be handled only by the averaged amount, and the reflectance can be calculated only after one scan. There is a problem that. Whether the accuracy deterioration by this method is within an allowable range depends on the accuracy required for calculating the magnification change ΔM,
The amount of change in magnification change ΔM during one scan, or the comparison between the time of one scan and the length of time constant T, or the difference in transmittance η of reticle R used due to the position of reticle R;
It is determined in consideration of the difference between the reflectivity r of the wafer W and the position of the reticle R. However, the time for one scan depends on the sensitivity of the resist, and the uniformity of the transmittance of the reticle used is also an uncertain factor. Therefore, in the present embodiment, the intensity of the reflected light from the wafer is determined based on the reference reflectance data created based on the intensity of the reflected light from the reference reflecting surface according to the position of the scan of the mask, and during the exposure operation. By scanning the reticle, a correct reflectance can be obtained even if the intensity of the reflected light changes according to the position of the reticle.

Next, a second embodiment of the present invention will be described. In the second embodiment, the light amount information (hereinafter, referred to as an “offset component”) reflected by the reticle R or the optical member in the illumination optical system is obtained without calculating the reference reflectance data using the reference reflection surface. The first embodiment differs from the first embodiment in that a value obtained by subtracting the offset component from the output Sb of the reflected light sensor 27 is used as the amount of light reflected by the wafer and incident again on the projection optical system PL. In the second embodiment, the same members as those in the first embodiment are denoted by the same reference numerals. Further, in the present embodiment, information for obtaining the light amount (light energy) incident on the projection optical system PL via the reticle, that is, the transmittance of the reticle (in the present embodiment, the light amount in the illumination area IA and the light shielding portion of the pattern) ) Is detected based on the output of the irradiation sensor 41 and the output of the light source sensor 28.

A description will now be given of obtaining the amount of light incident on the projection optical system PL via the reticle.

The main control system 100 calculates the ratio Sc / of the output Sa from the light source sensor 28 and the output Sc of the irradiation amount sensor 41.
Sa is stored in the memory in the main control system 100 in synchronization with the movement position of the reticle stage RST on which the reticle R is mounted for one scan. That is, main control system 100 moves reticle stage RST (wafer stage WST is stationary), and outputs output Sa from light source sensor 28 and irradiation amount sensor 41 according to the position of reticle stage RST detected by reticle interferometer 14. The output ratio Sc / Sa is converted into a time-series digital value and stored in a memory in the main control system 100. The data of this ratio becomes information corresponding to the change in transmittance during scanning of the reticle, and this ratio is hereinafter referred to as Rh. The timing of the storage in the memory (digital sampling) may be performed at every fixed movement amount (for example, every 0.01 μm to 10 μm) based on the resolution (for example, 0.01 μm) of the reticle interferometer 14 as described above. . Then, the stored ratio Rh of the output Sa from the light source sensor 28 and the output Sc of the irradiation amount sensor 41 that can change at each position of the reticle stage RST is stored in the memory in accordance with the position of the reticle stage RST. At the time of actual exposure, for example, at every predetermined time of about several milliseconds, the ratio Rh stored in advance in the memory corresponding to the position of the reticle stage RST is read, and the value is output to the output value Sa of the photoelectric sensor 28 at the time of actual exposure. (Photoelectric sensor 28 at predetermined time intervals
(Sa · Rh) is an estimated value of the amount of light (energy) incident on the projection optical system PL via the reticle every predetermined time. Since the main control system 100 is usually constituted by a digital computer, the ratio Rh and the ratio are set similarly to the digital sampling of various data in the first embodiment.
Alternatively, the multiplication result Sa · Rh may be averaged and the value may be stored, or the ratio Rh, which is sequentially calculated at about the resolution of the interferometer 14 (or a coarser resolution),
Alternatively, the multiplied value Sa · Rh may be stored as it is.

Next, detection of information on the amount of reflected light from the wafer will be described.

When considering the incident energy on the projection optical system PL, it is necessary to consider not only the amount of light incident via the reticle but also the amount of light reflected by the wafer and incident again on the projection optical system PL. Therefore, the amount of light re-entering the projection optical system PL from the wafer is detected based on the output Sb of the reflected light sensor 27. The main control system 100 moves the reticle stage RST by one scan while the reticle R is mounted, and performs time-series photoelectric conversion from the reflected light sensor 27 in accordance with the position of the reticle stage RST detected by the reticle interferometer 14. The signal Sb (light amount information) is stored (digitally sampled) in a memory in the main control system 100. The timing of storing the data in the memory may be set, for example, every fixed movement amount with reference to the resolution (for example, 0.01 μm) of the reticle interferometer 14. Also in this case, the interval of digital sampling does not need to match the resolution of the interferometer 14, and may be coarse, for example, every 0.2 μm to 10 μm.

At this time, the output S from the reflected light sensor 27
b includes light amount information of the light reflected by the reticle R and the optical member in the illumination optical system. Therefore, the reticle is scanned after the reference reflection surface of the reference plate FM having the reflection surface whose reflectance is almost zero is positioned in the projection area IA ′ of the projection optical system PL, and the reflected light is reflected by the reflected light sensor. 27, and a change in its output Sb is detected by a reticle stage RST.
Is stored in the memory according to the position of. The stored data becomes light amount information of the reflected light reflected by the reticle R or an optical member in the illumination optical system, and is hereinafter referred to as an offset component. At the time of actual exposure, the stored offset component may be subtracted from the output value Sb from the reflected light sensor 27.

When the photoelectric sensor 28, the irradiation amount sensor 41, and the reflected light sensor 27 receive the pulse light, the intensity may be measured for each pulse, or may be measured for a short period of time, for example, several to several tens. The power in the unit time of mSec may be integrated and output as the average power in the unit time.

Next, calculation of the amount of incident light E on the projection optical system PL will be described with reference to FIG.

Method for calculating the amount of incident light E on the projection optical system PL
The calculation of the amount of change in the imaging characteristics of the projection optical system PL
It is determined in the same manner as in the example. This will be briefly described below. Book
In the embodiment, Ea, Eb, and Ec in FIG.
From the reticle side using the position of the RST stage as a variable
Light quantity incident on the projection optical system PL and projection optics from the wafer side
This is the sum with the amount of light that reenters the system PL. Main control system 100
Is the sampling time t ₁Output S of the light source sensor 28
a and the output Sb of the reflected light sensor 27 are respectively detected. main
The control system 100 sets the sampling time t₁Position x corresponding to
₁Sa from the photoelectric sensor 28 and the irradiation amount sensor
-41 ratio Rh and offset component read from memory
You. The main control system 100 outputs the output S of the photoelectric sensor 28.
a multiplied by the ratio Rh and the output of the reflected light sensor 27
Subtract the offset component at that position (or time) from Sb
Add the value that was found. The main control system 100 performs this addition.
Value and shutter 2 opening / closing information (1 if open, 1 closed
Weight if 0) and the irradiation area of the wafer W (reticle
(Irradiation area determined by line 8) IA '
Pulling time t₁Energy to the projection optical system PL at
Lugie Ea is calculated as an estimated value.

[0082] The ratio Rh and when the position x ₁ which stores the offset component does not correspond to the sampling time t _1, the ratio Rh and offset components stored in the sampling time t ₁ after the nearest position x You should use.

Hereinafter, the incident energy is similarly obtained for the sampling times t _{2 to} t ₅ . Here, the incident energy corresponding to the sampling times t ₁ and t ₃ is E
a, the incident energy corresponding to the sampling times t ₂ and t ₅ is represented by Eb, and the incident energy corresponding to the sampling time t ₄ is represented by Ec.

Incidentally, similarly to the first embodiment, the incident energy is obtained by using the average value of each data at the sampling time interval Δt (for example, the time interval between the sampling times t ₁ and t ₂ ). You may. Specifically, for example, the interval between the above-mentioned ratio Rh and the digital sampling of the offset component is set to every 25 μm on the reticle, and the sampling time interval Δt = 5 between the sampling times t ₁ and t ₂ is set.
When msec and scan speed V = 50 mm / sec, ten pieces of sampling data are obtained for each of the ratio Rh and the offset component within the sampling time interval Δt between the sampling time t ₁ and the sampling time t ₂ . Accordingly, similarly to the first embodiment, the incident energy Eb may be obtained based on data obtained by averaging ten pieces of sampling data for each of the ratio Rh and the offset component.

Once the incident energy is obtained, the amount of magnification change at the sampling time is calculated by Δ in the same manner as in the first embodiment.
From M / E, the decay rate between each sampling time is obtained from the time constant T. Then, an envelope connecting the values at each sampling time is determined as the magnification fluctuation characteristic, and the magnification fluctuation characteristic shown in FIG. 8B can be obtained. And FIG.
The imaging characteristic control unit 30 determines the control amount of the pressure control system 40 or the drive amount of the drive elements 31, 34, and 35 so as to change the magnification according to the magnification change characteristic as shown in FIG. Is corrected.

Also in this embodiment, the reticle stage RST is moved in one direction to capture the ratio Rh and the offset component. Therefore, the reticle stage RS is moved in a direction different from the direction in which the ratio Rh and the offset component are captured.
When scanning T, the reading of the ratio Rh and the offset component is performed from the opposite direction.

In the above-described first and second embodiments, information relating to the transmittance of the reticle and information relating to the reflected light of the wafer are stored in accordance with the reticle coordinates.
Since the side is also scanned at the same time, the same effect can be obtained even if it is stored on the basis of the coordinates of the wafer stage or on the basis of time.
In the case of the wafer stage coordinate reference, it is necessary to reset the count of the interferometer to 0 every time the scan is started or to store the coordinates of the scan start point. Further, in the case of the time reference, it is necessary to change the time axis scale because the scanning speed is different when the exposure time is different due to the resist sensitivity or the like. Note that, although the accuracy is slightly lowered in the above-described embodiment, the change characteristic of the imaging characteristic of the projection optical system PL may be obtained based only on the amount of light incident on the projection optical system PL via the reticle.

Further, due to the change of the illumination condition due to the exchange of the diaphragm 29, the light passing position in the projection optical system PL is different, and the change characteristic of the image forming characteristic is different. For example, the thermal time constant related to the magnification change is different. Therefore, it is necessary to re-store information (for example, a thermal time constant) relating to the change characteristic of the imaging characteristic for each illumination condition changed by the aperture 29.

FIG. 9 shows the reticle blind 8 shown in FIG.
Planar shape, projection field if, and pattern area of reticle R
The layout relationship of each area PA is shown, and the reticle blind 8 is
Here, it is composed of two light shielding plates 8A and 8B. Light shield plate 8
B has a U-shaped planar shape, and has a scan direction (x direction).
Direction EGx defining an illumination area with respect to
_TwoAnd the illumination area in the y direction orthogonal to the scan direction.
Straight edge EGy that defines ₁, EGy_TwoAnd
On the other hand, the light shielding plate 8A defines an illumination area in the scanning direction.
Edge EGx of the light shielding plate 8B_TwoStraight parallel to
Line edge EGx₁In the x direction with respect to the light shielding plate 8B.
It is movable. Thereby, the slit-shaped illumination area
The width of the IA in the scanning direction becomes variable. In addition, the light shielding plate 8B
Can be moved in parallel in the x direction,
EGx to determine₁, EGx_TwoIs set symmetrically from the optical axis IX
You may make it. FIG. 10 shows the reticle bra of FIG.
Intensity distribution of illumination light reaching reticle R through India 8
FIG. 3 is a perspective view three-dimensionally showing a direction of an optical axis IX as an intensity axis.
I. Continuous light from mercury discharge lamps etc.
When using a source, this is not a problem,
When using a light source, the illuminance distribution in the scan direction is
Both ends in the scan direction of the illuminance distribution when rectangular
Due to variations in the amount of superposition and the number of superpositions
Of the exposure amount within one shot area on the wafer W
Tends to occur.

Therefore, as shown in FIG.
At least at the end in the scanning direction,
(Width ΔXs). Figure 10
Therefore, the length YSp of the illuminance distribution in the y direction is
Determined to cover the length of the turn area PA in the y direction
And the length of the illuminance distribution in the x direction (slit width) XSp
Is the target exposure amount for the photoresist on the wafer W,
Scan speed of wafer stage RST and wafer stage WST
Degree, pulse oscillation frequency for pulsed light source, illumination light intensity
It is determined optimally in consideration of the degree. As shown in FIG.
In order to have a slope of width ΔXs at both ends of the illuminance distribution
Is the edge EGx of the light shielding plate 8A in FIG.₁And light shielding plate 8B
Edge EGx_TwoIs conjugated to the pattern surface of reticle R.
From the desired position in the direction of the optical axis IX by a certain amount,
EGx₁, EGx_TwoRetick a slight defocused image of
What is necessary is just to project on R. However, non-scanning method
Direction edge EGy₁, EGy_TwoAbout the reticle R
To form a sharp image on the pattern surface, use the edge EG
y₁, EGy_TwoIs a position conjugate to the pattern surface of reticle R
Need to be placed accurately. Therefore, the edge EGy
₁, EGy_TwoAre precisely placed in the conjugate plane, and the edge EG
x₁, EGx_TwoIs the edge EGy₁, EGy_TwoSurface position
In a plane slightly shifted to the light source side. Also pickpocket
The longitudinal dimension (length YSp) of the socket-shaped illumination area IA is
To make it variable, the edge EGy₁, EGy _TwoAlso y
Must be movable in the direction. Note that y in the illuminance distribution in FIG.
The direction becomes uniformly inclined like the imaginary line LLi
The position ya in the y direction in FIG.₁Exposed by
Part within the boat area and the position ya_TwoShot exposed at
In this case, the exposure amount is different from that in the area inside the target area. There place
Place ya₁Strength I (ya₁) And position ya_TwoStrength I
(Ya_Two) And the ratio I (ya)₁) / I (ya
_Two), The slit width XSp is finely adjusted in the y direction.
Good to do. That is, the y direction of the slit-shaped illumination light IA
Position ya₁The width in the scanning direction at XSp (y
a₁), Position ya_TwoThe width in the scanning direction at XSp (y
a_Two), I (ya₁) / I (ya_Two) = XSp
(Ya_Two) / XSp (ya₁D)
EGx₁And EGx_TwoAre relatively parallel in the xy plane
Tilt (rotate) from the state. In short, Figure 9
Slit-shaped blind opening slightly shown in trapezoidal shape
It is. In this way, the slit-shaped illumination light
Slight illumination unevenness (uniform inclination) in the non-scanning direction of
The exact exposure at each point in the shot area.
Will be obtained.

When a pulse light source is used, it is necessary to perform pulse emission in a specific positional relationship while the reticle R and the wafer W are relatively scanned. FIG. 11 schematically shows the illuminance characteristics in the scanning direction when the pulse emission is performed in the specific positional relationship. In the case of a pulsed light source, the peak intensity value varies for each pulse, and when the average value is Im, the width (X) of the slit-shaped illumination area IA defined by half the intensity Im / 2 in the scanning direction (X
Pulse emission (trigger) at each distance interval such that (Ps + ΔXs) is exactly divisible by a predetermined integer value Np (except 1).
It does. For example, when the width (XPs + ΔXs) of the slit-shaped illumination area IA on the reticle is 8 mm,
Assuming that the integer value Np is 20, the pulse light source may emit light every time the reticle R scans 0.4 mm. The integer value Np is nothing but the number of pulses superimposed on an arbitrary point on the wafer W. For this reason, in order to average the variation of the peak intensity value for each pulse and achieve the desired exposure accuracy on the wafer, the minimum value of the integer value Np is automatically determined according to the variation of the intensity for each pulse. Come. By analogy with the current pulse light source (such as an excimer laser), the minimum value of the integer value Np is about 20.

In FIG. 11, since Np is schematically represented as 5, the inclination of the end of the illuminance distribution of the first pulse in the scanning direction is equal to the inclination of the tip of the illuminance distribution of the sixth pulse in the scanning direction. And overlap. At the start or end of scan exposure, pulse oscillation starts from a state where the entire slit-shaped illumination area IA (XPs + 2ΔXs in width) is located outside the pattern area PA of the reticle R, and the entire illumination area IA (width XPs + 2ΔXs)
Stops the pulse oscillation in a state in which reaches the outside of the pattern area PA.

The trigger method of the pulse light source is as follows.
One is possible. In response to a measurement value of the laser interferometer 14 (or 19) for measuring the position of the reticle stage RST (or the wafer stage WST) in the scanning direction, a trigger signal is sent to the pulse light source every predetermined movement amount. Is a position synchronization trigger method for sending The other is the reticle stage RS
T, a constant time interval (for example, 2 msec) responding to the constant speed while relying on the constant speed control of the wafer stage WST.
This is a time synchronization trigger method in which a clock signal is generated every time and the clock signal is sent to a pulse light source as a trigger signal. Since both methods have advantages and disadvantages, they may be used as appropriate.
However, in the time synchronization trigger method, the generation start timing and the stop timing of the clock signal are determined by the laser interferometer 1.
It must be determined in response to 4, or 19 measurements.

When the priority is given to shortening the exposure processing time of one shot area as much as possible, the reticle is set so that the pulsed light source oscillates at the rated maximum oscillation frequency on the assumption that the target exposure amount can be obtained. It is desirable to set the speed of the stage RST, the speed of the wafer stage WST, the width (XPs) of the slit-shaped illumination area IA, and the peak intensity of the pulse.

Further, as described in each of the above embodiments, only the reticle R is scanned and the output Sa of the photoelectric sensor 28 is output.
When sampling the output Sb of the reflected light sensor 27 to create various data, or sampling the output Sa or Sb during scan exposure when the pulsed light source is oscillating by the time synchronous trigger method, Sampling may be performed in response to a trigger clock signal.

In the above embodiment, the intensity of the illuminating light passing through the mask on the substrate stage side is sequentially stored in synchronization with the movement of the mask stage. In other words, since the illumination light intensity is stored according to the scan position of the mask, even if the energy incident on the projection optical system changes by scanning the mask during the exposure operation, the change in the imaging characteristics caused by the exposure light absorption changes. Since the illumination light intensity corresponding to the position of the mask can be used for the calculation of the above, no inconvenience occurs.

In the above-described embodiment, since the energy incident on the projection optical system is calculated in consideration of the information on the reflected light from the photosensitive substrate, the change in the imaging characteristics due to the exposure light absorption can be accurately obtained.

Further, since the amount of change in the imaging characteristic can be accurately calculated based on the amount of incident energy to the projection optical system which changes according to the position of the mask, the image can be formed without error even in a scan type exposure apparatus. Characteristics can be corrected.

[0099]

According to the present invention, even when a pulse light source that emits pulsed illumination light is used for scan-type exposure, an exposure amount can be accurately given to each point in a shot area on a substrate. .

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a scan type exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing scan exposure in the apparatus of FIG.

FIG. 3 is a diagram showing details around a wafer stage of the apparatus of FIG. 1;

FIG. 4 is a diagram showing a relationship between incident energy and magnification change.

FIG. 5 is a diagram illustrating the incident energy and the amount of change in the imaging characteristic when the incident energy is different for each position (time).

FIG. 6 is a diagram showing a relationship between a reflectance and a reference reflectance.

FIG. 7 is a diagram showing a change in reticle transmittance when a reticle is moved.

FIG. 8 is a diagram for explaining the output of the reflected light sensor on the reference reflecting surface and the principle of the reflectance calculation method.

FIG. 9 is a diagram illustrating a relationship between a planar shape of a reticle blind and a projection visual field.

FIG. 10 is a perspective view three-dimensionally showing an illuminance distribution of illumination light.

FIG. 11 is a diagram schematically showing an illuminance distribution in a scanning direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Light source 13 ... Reticle stage drive part 18 ... Wafer stage drive part 22 and 23 ... Wafer position detection system 25 ... Focus detection part 27 ... Reflection light sensor 28 ... Light source sensor 30 ... Imaging characteristic control part 31, 32, 33 ... Driving element 36 Irradiation sensor 40 Pressure controller 100 Main control system R Reticle W Wafer FM Reference plane RST Reticle stage WST Wafer stage

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-280619 (JP, A) JP-A-2-229423 (JP, A) JP-A-60-158449 (JP, A) JP-A-2- 181416 (JP, A) JP-A-2-74024 (JP, A) JP-A-5-291117 (JP, A) JP-A-2-106917 (JP, A) JP-A-4-277612 (JP, A) JP-A-4-196513 (JP, A) JP-A-63-58349 (JP, A) JP-A-5-144700 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (19)

(57) [Claims] 1. A scan for scanning and exposing a substrate by moving a mask in a predetermined scanning direction with respect to an illumination area of illumination light pulsed and moving the substrate in a direction corresponding to the scanning direction. In the exposure method, at least an end of the intensity distribution of the illumination light in the scanning direction is inclined, and a width of the illumination area defined by half the intensity of the illumination light in the scanning direction is a predetermined uniformity. The illumination light is pulsed at intervals of a distance exactly divisible by a numerical value, and the exposure amount control for the substrate is performed according to the intensity unevenness of the illumination light in a direction orthogonal to the scanning direction. Scanning exposure method. 2. The method according to claim 1, wherein said exposure amount control adjusts an intensity distribution of said illumination light on a plane substantially conjugate with a pattern plane of said mask. 3. The method according to claim 1, wherein the control of the exposure amount is performed by adjusting a shape of an irradiation area of the illumination light. 4. The method of claim 18, wherein said illumination light is pulsed at a predetermined rated maximum frequency. 5. The moving speed of the substrate according to claim 4, wherein the moving speed of the substrate is set such that a target exposure amount for the substrate is obtained when the illumination light is pulsed at the rated maximum frequency. Method. 6. The apparatus according to claim 4, wherein the intensity of the illumination light is set such that a target exposure amount for the substrate is obtained when the illumination light is pulsed at the rated maximum frequency. The described method. 7. An element manufacturing method, comprising a step of scanning and exposing the substrate by using the method according to claim 1. 8. A method for moving a mask and a substrate in synchronization with each other.
In a scanning exposure apparatus for scanning and exposing the substrate,
Based on the trigger signal generated at regular time intervals.
A light source that emits pulsed illumination light, and the mask or
Hold the substrate and move it in a predetermined direction for the synchronous movement.
A movable stage, and a position of the stage in the predetermined direction.
An interferometer for measuring the position information, and generating the trigger signal.
The timing to start the production is based on the measured value of the interferometer
Scanning dew, characterized by determining Light device. 9. A method for moving a mask and a substrate in synchronization with each other.
In a scanning exposure apparatus for scanning and exposing the substrate,
Based on the trigger signal generated at regular time intervals.
A light source that emits pulsed illumination light, and the mask or
Hold the substrate and move it in a predetermined direction for the synchronous movement.
A movable stage, and a position of the stage in the predetermined direction.
An interferometer for measuring the position information, and generating the trigger signal.
The timing to stop the production is based on the measured value of the interferometer
A scanning type exposure apparatus characterized in that it is determined by: 10. Synchronously moving a mask and a substrate.
A scanning exposure apparatus for scanning and exposing the substrate.
A light source that emits pulsed illumination light, and the mask or
Holding the substrate, in a predetermined direction for the synchronous movement
A movable stage and the stage in the predetermined direction.
An interferometer for measuring position information, and
Loose light is emitted for each predetermined amount of movement based on the measurement value of the interferometer.
A first light emission method based on a trigger signal generated at
Light emission based on a trigger signal generated at every time interval of
And the second light emitting method is used.
The start and stop of pulse emission from the light source
Determining the imaging based on the measurements of the interferometer
A scanning exposure apparatus. 11. The light source is illuminated at a predetermined rated maximum frequency.
The light is emitted in a pulsed manner.
An apparatus according to claim 1. 12. Pulse emission at the rated maximum frequency
Use the illumination light to achieve the desired target exposure.
Setting a moving speed of the substrate during the scanning exposure.
12. The device of claim 11, wherein the device is a device. 13. A pulse light emission at the rated maximum frequency.
Use the illumination light to achieve the desired target exposure.
Setting the intensity of the illumination light during the scanning exposure.
The apparatus according to claim 11 or 12, wherein 14. A pulse light is emitted at the rated maximum frequency.
Use the illumination light to achieve the desired target exposure.
In the predetermined direction of the illumination area of the illumination light during the scanning exposure
14. The method according to claim 11, wherein the width is set.
An apparatus according to any one of the preceding claims. 15. The method according to claim 8, wherein:
Comprising a step of scanning and exposing the substrate using the apparatus of claim
Production method. 16. A mask and a base for illuminating light during scanning exposure.
Used with a scanning exposure system that moves the plate synchronously
Generated at regular time intervals during the scanning exposure.
A scanning exposure device that emits a pulse of the illumination light based on a trigger signal.
A laser device for light, wherein the scanning exposure system comprises:
Holds the mask or the substrate during the scanning exposure
Stage that can move in a predetermined direction
Having an interferometer for measuring position information in the predetermined direction,
The timing for starting the generation of the trigger signal is determined by the interferometer.
For scanning exposure, characterized by being determined based on measured values
Laser device. 17. The illumination light according to claim 1, wherein said illumination light has a predetermined rated maximum frequency.
17. The method according to claim 16, wherein the light is emitted in a pulsed manner.
Laser device. 18. A mask and a base for illuminating light during scanning exposure.
Used with a scanning exposure system that moves the plate synchronously
Generated at regular time intervals during the scanning exposure.
A scanning exposure device that emits a pulse of the illumination light based on a trigger signal.
A laser device for light, wherein the scanning exposure system comprises:
Holds the mask or the substrate during the scanning exposure
Stage that can move in a predetermined direction
Having an interferometer for measuring position information in the predetermined direction,
The timing of stopping the generation of the trigger signal is determined by the interferometer.
For scanning exposure, characterized by being determined based on measured values
Laser device. 19. The illumination light according to claim 1, wherein said illumination light has a predetermined rated maximum frequency.
19. The method according to claim 18, wherein the light is emitted in pulses.
Laser device.