KR20050025626A - Position measuring method, position control method, exposure method and exposure apparatus, and device manufacturing method - Google Patents

Abstract

Position information on the scanning direction and nonscanning direction of a reticle stage (RST) is determined according to the result of the measurement using a reticle Y interferometer (13y1, 13y2) and a reticle X interferometer (13x). Position information on the scanning direction of a wafer stage (WST) is determined according to the result of the measurement using a wafer interferometer. According to the result of the determination of the position information on the nonscanning direction of the reticle stage and correlation information representing the relation between the prestored error of the measurement of the position of the reference points on reflecting surfaces (15y1, 15y2) and the corresponding position concerning the nonscanning direction of the reticle stage, position information on the reticle stage corrected with respect to the error of the measurement by the reticle Y interferometer is determined. According to the corrected position information and the position information on the scanning direction of the wafer stage, the stages are driven and controlled.

Description

Position measurement method, position control method, exposure method and exposure device, and device manufacturing method {POSITION MEASURING METHOD, POSITION CONTROL METHOD, EXPOSURE METHOD AND EXPOSURE APPARATUS, AND DEVICE MANUFACTURING METHOD}

Technical Field

The present invention relates to a position measuring method, a position control method, an exposure method and an exposure apparatus, and a device manufacturing method. For example, an exposure apparatus suitable for implementing a position measuring method measured using a laser interferometer, a position control method using the measuring method, an exposure method using the position control method, and the position measuring method, etc., and the exposure method or the exposure apparatus. It relates to a device manufacturing method using.

Background

Background Art [0002] Conventionally, in lithography processes for manufacturing semiconductor devices, liquid crystal display devices, etc., a pattern formed on a mask or a reticle (hereinafter referred to collectively as a "reticle") is coated with a photosensitive agent such as a resist through a projection optical system or a glass plate. The exposure apparatus which transfers on the board | substrate (henceforth "wafer") is used. As such exposure apparatuses, so-called stationary projection exposure apparatuses such as steppers and so-called scanning projection exposure apparatuses such as scanning steppers are mainly used.

In particular, in the scanning projection exposure apparatus, it is necessary to move not only the wafer stage on which the wafer is mounted but also the reticle stage on which the reticle is mounted with respect to the predetermined scanning direction. For this reason, in most scanning projection exposure apparatuses, a laser interferometer having high measurement accuracy, which is a kind of an optical interference measuring instrument, is used as a measuring device for measuring the position in the scanning direction and the non-scanning direction of the reticle stage. In addition, since the accuracy of the measurement of the scanning direction position of the reticle stage greatly affects the lamination accuracy and the synchronization accuracy of the wafer and the reticle, the recent scanning projection exposure apparatus suffers from deterioration of the position measurement accuracy due to the rotational error of the reticle stage. In view of prevention, a retro-reflector having a sufficiently small reduction in measurement accuracy due to a kind of so-called aveo error due to the formation accuracy of the reflecting surface and the rotational error of the reticle stage is adopted as the moving mirror for the laser interferometer. There are relatively many. This is because the retro-reflector emits the reflected light beam along an axis parallel to the incident light axis, and therefore, the probability of light amount decrease of the returned light beam is particularly low due to the influence of the remaining rotational error of the reticle stage.

According to the laser interferometer provided with such a moving mirror, it is possible to measure the position measurement of the moving object with a resolution of about 0.5 nm to 1 nm.

However, with high integration of semiconductor devices (integrated circuits, etc.), circuit patterns have been miniaturized year by year, and as a result, total and overlay errors allowable in recent exposure apparatuses are very small, and the position measurement error of the reticle stage can be further reduced. There is a need.

As a result of intensive research, the inventors found that the misalignment of the optical axis (measurement optical axis) of the measurement beam with respect to the optical axis (reference optical axis) of the reference beam in the laser interferometer, which has not been noticed at all, can be a major factor of measurement error. The shift of the optical axis occurs even when the moving mirror reflecting surface is in an ideal attachment state, and it is also found that the optical axis changes depending on the position of the reticle stage. This will be described in more detail below.

a. The deviation of the measurement optical axis from the reference optical axis is a cause of measurement error because wavefront aberration is usually present in the reference beam and the measurement beam of the laser interferometer.

That is, as shown in Fig. 9A, there are wavefront aberrations in both the reference beam Ra (the optical axis thereof is the reference optical axis) and the measurement beam Ma (the optical axis thereof is the measurement optical axis), but there is no optical axis deviation between the two beams. The reference state is taken. And as shown in FIG. 9B, when the measurement optical axis is shift | deviated with respect to the reference optical axis, as can be understood when comparing the width WD1 and the width WD2 <WD1 of FIG. 9A, as for both beams Ra and Ma, The interference part (this part determines the measurement result) becomes relatively narrow. As a result, as can be seen from comparing the shift amount ΔL1 in FIG. 9A with the shift amount ΔL2 in the case of FIG. 9B, the interference portion shows the relative of the wavefronts of both beams Ra and Ma. The position is clearly different from the reference state, and a measurement error of δL (= ΔL1-ΔL2) occurs.

In addition, wavefront aberration is generated in the reference beam and the measurement beam of the laser interferometer by transmitting these beams through glass (transmission optical elements such as lenses) or reflecting off the glass surface (reflection optical elements such as mirrors) in the optical path. Alternatively, even when wavefront aberration occurs because the reference beam and the measurement beam are relatively inclined, the same measurement error occurs as when the wavefront aberration exists.

b. Next, the cause of the optical axis shift will be described. That is, the position of the direction (also called the measurement orthogonal direction) orthogonal to the measurement direction of the moving object (reticle stage, etc.) is at a predetermined position, and at this time, the reference beam irradiated to the reference mirror 14y ₁ as shown in FIG. 10A. The case where the optical axis (measurement optical axis) of the measurement beam Ma irradiated to the moving mirror 15y ₁ to the optical axis (reference optical axis) of Ra is exactly the state (reference state) superimposed. From the state of FIG. 10A, when the moving body moves Δ in the measurement orthogonal direction (in this case, the amount of movement of the vertex of the moving mirror 15y ₁ is also Δ), the optical axis of the measuring beam Ma (measurement optical axis) 2 (DELTA) shifts from this reference state of FIG. In this case, it will be clear that the shift amount 2Δ changes depending on the position in the measurement orthogonal direction of the moving object.

Although not shown, a so-called double pass laser interferometer in which a measuring beam is incident on a retro reflector or the like and the emitted light is reflected by a reflecting mirror to receive a return light in which the reflected light is returned in the opposite direction along the same optical path. You can think of the case. In this case, when the reflection mirror is inclined and attached, if the optical axis shift occurs due to the position change of the moving object as described above, the measurement direction position of the incident point (reflection point) of the measurement beam on the reflection mirror changes from the reference state. As a result, measurement errors occur regardless of the presence or absence of wavefront aberration of the beam.

As described above, measurement errors occur due to the interaction between the wave front aberration of the beam and the degree of overlap of the beams (hereinafter referred to as "work off"), but measurement errors due to these factors have not been considered until now.

In addition, the inventors confirmed that both the wavefront aberration and the workoff amount were high in reproducibility.

This invention is made | formed based on the said novel knowledge acquired by the inventor, The 1st objective is that the position information of the at least 1-axis direction of the movable body in which the reflecting surface was formed can be measured accurately using an optical interference measuring instrument. It is providing a position measuring method.

It is a second object of the present invention to provide a position control method for precisely controlling the position of a moving object whose position information in at least one axial direction is measured using an optical interference measuring instrument.

It is a third object of the present invention to provide an exposure method for realizing high-precision exposure by a scanning exposure method.

It is a fourth object of the present invention to provide an exposure apparatus that realizes high-precision exposure by a scanning exposure method.

The 5th object of this invention is to provide the device manufacturing method which can improve the productivity of a device.

Disclosure of the Invention

The present invention is a position measuring method for measuring position information in at least one axial direction of a moving object on which a reflective surface is formed by using an optical interference measuring instrument, wherein the reflective surface is irradiated with a measuring beam and reflected light thereof. The position information of the movable body in the first axial direction is measured based on the output of the optical interference measuring instrument receiving the inside, and the position information of the movable body in the second axial direction orthogonal to the first axis is measured. Measuring by using a second axial position measuring device; The position measurement error of the reference point on the reflective surface at least due to the positional relationship between the optical axis of the measurement beam of the optical interference interference measuring instrument and the optical axis of the reference beam and the positional relationship of the movable body with respect to the second axial direction corresponding thereto Calculating a measurement error of the positional information of the movable body with respect to the first axial direction by the wave interference measuring instrument based on the correlation information indicated and the positional information of the movable body with respect to the measured second axis direction; ; Position measurement method comprising a.

According to this, in the position measurement of the movable body, the position information of the movable body in the first axial direction is measured based on the output of the optical interference measuring instrument that irradiates the measuring beam to the reflecting surface on the movable body and receives the reflected light beam. At the same time, the positional information of the moving object in the second axial direction orthogonal to the first axis is measured using the second axial position measuring device. Next, the position measurement error of the reference point on the reflective surface at least due to the positional relationship between the optical axis of the measurement beam of the optical interference interference measuring instrument and the optical axis of the reference beam and the positional relationship of the moving object with respect to the second axis direction corresponding thereto Based on the correlation information and the position information of the movable body in the measured second axial direction, a measurement error of the position information of the movable body in the first axial direction by the wave interference measuring instrument is calculated. This makes it possible to correct the positional information of the moving object with respect to the first axial direction measured based on the output of the optical interference interference measuring instrument, by using the measurement error, and to correct the measurement error. It is possible to obtain the positional information of the moving object with respect to the direction. That is, it becomes possible to obtain the positional information which correct | amended the position measurement error of the movable body about the 1st axial direction resulting from the optical axis shift of the optical interference interference measuring instrument according to the position of the 2nd axial direction of the movable body. Therefore, the positional information in the at least one axial direction of the movable body on which the reflecting surface is formed can be measured with high accuracy using an optical interference measuring instrument.

In this case, prior to the measuring step, the position in the first axial direction of the movable body is detected based on the output of the wave interference measuring instrument that irradiates a measurement beam to the reflective surface and receives the reflected light beam. By using the second axial position measuring device, the movable body is moved in the second axial direction to obtain the position measurement error of the reference point on the reflective surface at a plurality of positions in the second axial direction, respectively. The method may further include the step of creating the correlation information based on the position measurement error obtained for each position.

In this case, various methods for obtaining the position measurement error of the reference position on the reflective surface can be considered. For example, the position measurement error of the reference point on the reflecting surface is calculated by a predetermined calculation based on the deviation amount of the measurement optical axis of the optical interference interference measuring instrument with respect to the reference optical axis and the position information of the moving object in the second axis direction. Can be. However, considering that the walkoff amount of the beam is high in reproducibility. The position measurement error of the reference point on the reflective surface may be obtained based on the measurement result of measuring the positional relationship between the measurement mark formed on a part of the moving object and the reference mark formed on the reference object.

In the position measuring method of the present invention, in the case of including the step of preparing the above-mentioned correlation information prior to the measuring step, the correlation information specifies a position measurement error of the reference point on the reflective surface obtained for each position in the second axial direction. It may be data of a function calculated based on the data of each plot point plotted on the coordinate system of, or the said correlation information is a position measurement error of the reference point on the said reflection surface calculated | required for every position of the said 2nd axial direction It can also be the table data created using.

In the position measuring method of the present invention, in the case of including the step of creating the above-mentioned correlation information prior to the measuring step, in the step of calculating the measurement error, according to the measured position information of the movable body with respect to the measured second axis direction The measurement error may be calculated using an operation result obtained by interpolating the position measurement error for each position in the second axial direction among the correlation information by a predetermined interpolation operation.

In the position measuring method of the present invention, in the case of including the step of creating the above-mentioned correlation information prior to the step of measuring, in the step of creating the correlation information, the movement of the moving object is based on the output of the wave interference measuring instrument. The movable body can be moved in the second axial direction while substantially maintaining the position in the first axial direction at a predetermined coordinate position.

In the position measuring method of the present invention, in the step of calculating the measurement error, the measurement error may be calculated by further considering the posture of the moving object. Here, the posture of the movable body includes at least one of yawing, rolling, and pitching of the movable body.

In the position measuring method of the present invention, the position measuring error included in the correlation information can be attributable to wavefront aberration occurring at least in the measurement beam. In the present specification, the wavefront aberration includes both wavefront aberrations caused by the measurement beam being relatively inclined with respect to the reference beam, in addition to wavefront aberrations generated when the measurement beam is transmitted to or reflected from the optical element on the optical path. do.

In the position measuring method of the present invention, a reflecting surface other than a prism may be used as the reflecting surface, but the reflecting surface may be a reflecting surface of a hollow retro reflector fixed to the movable body.

In the position measuring method of this invention, the process of calculating the positional information of the said moving body regarding the said 1st axial direction by which the said measurement error was corrected; It may be further included.

The present invention is a position control method of controlling the position of a moving object whose position information in at least one axial direction is measured using an optical interference measuring instrument as viewed from a second point of view. A position measuring step of measuring position information of the first axis direction of the apparatus; Controlling at least the position in the first axial direction of the movable body in consideration of the information obtained in the position measuring step; Position control method comprising a.

According to this, since the position information regarding the 1st axial direction of a movable body is measured by implementing the position measuring method of this invention, the positional information of the 1st axial direction of the movable body is measured precisely using a wave interference measuring instrument. can do. And based on this precisely measured positional information, since the positional information of the at least 1 axial direction (1st axial direction) controls the position of the 1st axial direction of the moving body measured using a wave interference measuring instrument, It becomes possible to control the position of the moving body with high precision.

According to a third aspect of the present invention, there is provided an exposure method for transferring a pattern formed on the mask onto the photosensitive object by synchronously moving a mask and a photosensitive object in a predetermined direction, wherein the first movable body and the photosensitive object on which the mask is mounted are mounted. The position information in at least one of the predetermined directions of the second movable body on which the micrometer is mounted is measured by using the position measuring method of the present invention, and at least one of the first movable body and the second movable body in consideration of the information obtained as a result of the measurement. An exposure method of transferring the pattern onto the photosensitive object by controlling the position in the predetermined direction.

According to this, the positional information of the at least one predetermined direction (synchronous movement direction) of the 1st movable body on which a mask is mounted, and the 2nd movable body on which the photosensitive object is mounted is measured using the position measuring method of this invention, and the measurement In consideration of the resultant information, the pattern is transferred onto the photosensitive object by controlling the position in a predetermined direction of at least one of the first movable body and the second movable body (for example, the movable body to be the tracking side in synchronous movement). Therefore, the position control enables the scanning method to realize the improvement of the synchronous accuracy of the first movable body and the second movable body, that is, the mask and the photosensitive object, the shortening of the synchronous settling time, and the high density by the scanning method. The pattern of can be accurately transferred onto the photosensitive object.

According to a fourth aspect of the present invention, an exposure apparatus for synchronously moving a mask and a photosensitive object in a predetermined scanning direction to transfer a pattern formed on the mask onto the photosensitive object, wherein the mask is mounted and a reflecting surface is formed. First stage; A second stage on which the photosensitive object is mounted; A drive system for driving the first stage and the second stage; An optical interference measuring instrument for irradiating a measurement beam to the reflecting surface and measuring position information of the first stage with respect to the scanning direction, and position information for the non-scanning direction orthogonal to the scanning direction of the first stage; A first measuring system having a measuring device for measuring; A second measurement system for measuring positional information relating to at least the scanning direction of the second stage; Position measurement error of the reference point on the reflecting surface and at least corresponding to the measurement result of the first and second measurement systems and the positional relationship between the optical axis of the measurement beam of the optical interference interference measuring instrument and the optical axis of the reference beam A control device for controlling the drive system based on correlation information indicating a positional relationship of the first stage with respect to the non-scanning direction; It is a 1st exposure apparatus provided with.

According to this, a 1st measuring system irradiates a measuring beam to the reflecting surface formed in the 1st stage from the wave interference measuring instrument, measures the positional information regarding the scanning direction of a 1st stage, and uses a 1st measuring device using a measuring apparatus. The positional information regarding the non-scanning direction of the stage is measured. On the other hand, the second measurement system measures positional information regarding at least the scanning direction of the second stage. Then, the control device determines the position measurement error of the reference point on the reflective surface at least due to the measurement result of the first and second measurement systems, and the positional relationship between the optical axis of the measurement beam of the optical interference measuring instrument and the optical axis of the reference beam. The drive system is controlled based on correlation information indicating a positional relationship of the first stage with respect to the non-scanning direction corresponding to. That is, the control apparatus in consideration of the position measurement error in the scanning direction of the first stage due to the optical axis shift (deviation of the measurement optical axis from the reference optical axis of the measurement optical axis) according to the position in the non-scan direction of the first stage, By means of the drive system, synchronous control of the first stage and the second stage, that is, synchronous control of the mask and the photosensitive object, is performed with high accuracy. As a result, the synchronous accuracy of the mask and the photosensitive object can be improved, the synchronous correction time can be shortened, and the high-precision exposure can be realized by the scanning exposure method, and the mask pattern can be accurately transferred onto the photosensitive object.

In this case, the control device uses the correlation information and the positional information about the non-scanning direction of the first stage, and the control device is caused by the measurement error of the first stage by the optical interference measuring instrument. The relative positional error with respect to the scanning direction of the mask and the photosensitive object can be corrected.

In the first exposure apparatus of the present invention, the control apparatus relates to a measurement error of the first stage by the light interference interference measuring instrument based on the correlation information and position information on the non-scanning direction of the first stage. Information may be calculated to use the calculated information when the first stage moves in the scanning direction. Alternatively, the control device may be configured to adjust the position of the first stage in the scanning direction based on the correlation information and the positional information of the non-scanning direction of the first stage. Information may be calculated to use the calculated information when the first stage moves in the scanning direction.

In the first exposure apparatus of the present invention, the correlation information includes the first stage through the drive system while the control apparatus detects the position of the scanning direction of the first stage based on the output of the optical interference measuring instrument. Can be made in advance in the non-scanning direction based on the position measurement error of the reference point on the reflective surface respectively obtained at a plurality of positions in the non-scanning direction.

In this case, the control device may include a storage device that controls the movement of the first stage through the drive system at the time of creating the correlation information and stores the created correlation information.

In the first exposure apparatus of the present invention, in the case of further comprising a mark measuring instrument for measuring the positional relationship between the measurement mark formed on a part of the first stage and the reference mark formed on the reference object, the measurement of the mark measurement instrument is performed. The correlation information can be prepared in advance based on the position measurement error of the reference point on the reflective surface obtained based on the result.

In the first exposure apparatus of the present invention, the correlation information may be table data created by using a position measurement error of a reference point on the reflective surface obtained for each position in the non-scanning direction.

In this case, the control apparatus interpolates the position measurement error for each position in the non-scan direction among the correlation information by a predetermined interpolation operation according to the measured position information on the non-scan direction of the first stage. It is possible to calculate the measurement error of the wave interference measuring instrument by using the calculation result.

In the first exposure apparatus of the present invention, the correlation information includes a function of calculating a position measurement error of a reference point on the reflective surface obtained for each position in the non-scanning direction based on data of each plot point plotted on a predetermined coordinate system. It can be data.

In the first exposure apparatus of the present invention, when preparing the correlation information, the control apparatus maintains the first stage substantially at the predetermined position with respect to the scanning direction based on the output of the optical interference measuring instrument. It can be made to move in a scanning direction.

In the first exposure apparatus of the present invention, the control apparatus may calculate the position measurement error by further considering the posture of the first stage.

In the first exposure apparatus of the present invention, the position measurement error included in the correlation information may be further caused by wavefront aberration generated in the measurement beam.

In the first exposure apparatus of the present invention, the reflective surface may be a reflective surface of the hollow retro reflector.

According to a fifth aspect of the present invention, there is provided an exposure apparatus for synchronously moving a first object and a second object to transfer a pattern of the first object onto the second object, wherein the first movable body holds the first object. A stage system having a sieve, a second movable body for holding the second object, and a drive system for independently driving the first and second movable bodies, respectively; A first interferometer system for irradiating a measuring beam to a retro reflector formed on the first movable body to measure positional information of the first movable body regarding a scanning direction in which the first object is synchronously moved; A second interferometer system for measuring positional information of the second movable body; A control device for controlling the drive system based on measurement results of the first and second interferometer systems and error information on position measurement of the first movable body due to the retro reflector; It is a 2nd exposure apparatus provided with.

According to this, error information regarding the measurement results of the first and second interferometer systems and the position measurement of the first movable body due to the retro reflector (for example, the positional change in the measurement orthogonal direction of the retro reflector by the control device) Drive system is controlled based on the error information regarding the position measurement of the first movable body caused by the optical axis shift of the measurement optical axis with respect to the reference optical axis. That is, in consideration of the error information regarding the position measurement of the first movable body due to the retro-reflector, the synchronous control of the first movable body and the second movable body is precisely performed by the control apparatus via the drive system. As a result, the synchronization accuracy of the first object and the second object can be improved, the synchronization correction time can be shortened, and the high-precision exposure is realized by the scanning exposure method, so that the pattern of the first object can be accurately transferred onto the second object. It becomes possible.

In this case, the control device may control the drive system using different error information depending on the position of the first movable body in the non-scanning direction orthogonal to the scanning direction.

Further, in the lithography process, the pattern of the microdevice is transferred onto the photosensitive object by using the exposure method of the present invention, so that the pattern can be formed on the photosensitive object with high accuracy, thereby producing a higher degree of integration of the microdevice with good yield. can do. In the lithography process, by exposing using either the first or second exposure apparatus of the present invention, a pattern can be formed on the photosensitive object with high accuracy, thereby producing a higher integration micro device with better yield. Can be. Therefore, from another viewpoint, this invention can also be called the device manufacturing method using either the exposure method of this invention or the 1st, 2nd exposure apparatus of this invention.

Brief description of the drawings

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structure of the exposure apparatus of one Embodiment of this invention.

2 shows a reticle stage of FIG. 1, a reticle interferometer for measuring the position of the reticle stage, and a reticle alignment for simultaneously measuring a mark on a reticle (R) or a reticle reference plate (RFM) and a reference mark on a reference mark plate (FM) It is a perspective view which pulls out components, such as a system, and shows them.

3A is a plan view showing the arrangement of the reference marks WM ₁ , WM ₂ on the reference mark plate FM, and FIG. 3B is a plan view showing the arrangement of the measurement marks on the reticle reference plate RFM.

4 is a flowchart showing a processing algorithm of the main controller (internal CPU) at the time of preparing correlation information for correcting measurement error of a reticle Y interferometer.

5A, 5C, 5E, 5G, and 5I show measurement errors of a mark image measured by one reticle alignment system RA ₁ and one reticle Y interferometer obtained based on the image; 5B, 5D, 5F, 5H, and 5J are diagrams showing measurement errors of a mark image measured by the other reticle alignment system RA ₂ and the other reticle Y interferometer obtained based on the image. .

6A is a diagram showing a plurality of points corresponding to measurement errors of one reticle Y interferometer plotted on a rectangular coordinate system and an approximation curve of these points; FIG. 6B is a measurement error of the other reticle Y interferometer plotted on a rectangular coordinate system. It is a figure which shows the several point corresponding to and an approximation curve of these points.

7 is a flowchart for explaining an embodiment of the device manufacturing method of the present invention.

FIG. 8 is a flowchart showing a detailed example of step 204 of FIG.

9A and 9B are diagrams for explaining the principle of measurement error caused by the interaction between optical axis shift and wavefront aberration between the reference beam and the measurement beam.

10A and 10B are diagrams for explaining the principle that optical axis shift occurs between the reference beam and the measurement beam by the movement in the measurement orthogonal direction of the moving mirror (moving member).

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described based on FIGS. 1-6B. Fig. 1 shows a schematic configuration of an exposure apparatus 100 according to one embodiment which is preferable for carrying out the position measuring method, the position control method, and the exposure method of the present invention. This exposure apparatus 100 is a step-and-scan scanning projection exposure apparatus, that is, a so-called scanning stepper.

The exposure apparatus 100 includes an illumination system 10 including a light source and an illumination optical system, a reticle stage RST as a first stage (first moving body, moving body) holding a reticle R as a mask, and a projection optical system PL ), A wafer stage WST as a second stage (second movable body) capable of holding the wafer W as a photosensitive object and freely moving in the XY plane, a body BD mounted with a projection optical system PL, and the like. Doing.

The illumination system 10 includes a light source (not shown), a beam shaping optical system, an energy conditioner, an optical integrator (such as a fly's eye lens, a rod-type (internal reflection) integrator or a diffractive optical element), an illumination system An illumination optical system including an aperture stop plate, a beam splitter, a relay optical system, a fixed reticle blind, and a movable reticle blind (all not shown) is provided. The illumination system 10 is a rectangular (for example rectangular) slit-shaped illumination area IAR (opening of the fixed reticle blind) that extends narrow and long in the X-axis direction on the reticle R held on the reticle stage RST. Illuminated by a uniform illuminance distribution. The structure of the illumination system similar to this embodiment is disclosed in detail in Unexamined-Japanese-Patent No. 6-349701, US Patent No. 5,534,970, Japanese Unexamined-Japanese-Patent No. 2000-260682, etc., for example. As long as the national law of the designated country or selected country specified in this international application permits, the disclosure in the above-described US patent is incorporated herein by reference.

As the light source, a KrF excimer laser (oscillation wavelength 248 nm), an ArF excimer laser (oscillation wavelength 193 nm), an F ₂ laser (oscillation wavelength 157 nm), or the like is used. This light source is actually installed in a floor surface F in a clean room in which the exposure apparatus main body is installed or in a room (service room) having a low cleanness different from the clean room, and the above-described optical system is not described. It is connected to the incidence end of the illumination optical system.

The reticle stage RST is, for example, about several micrometers by an air bearing (not shown) formed on its bottom surface above the upper surface of the reticle base 36 constituting the top plate portion of the second column 34 described later. Injury is supported through clearance. On this reticle stage RST, the reticle R is fixed by vacuum adsorption (or electrostatic adsorption), for example. The reticle stage RST is here two-dimensionally in the XY plane perpendicular to the optical axis AX of the projection optical system PL, which will be described later, by the reticle stage driver 12 including a linear motor or the like (X axis). In the direction of rotation (theta z direction) around the Z-axis orthogonal to the direction, the Y-axis direction and the XY plane, micro-driving is possible, and the reticle base 36 can be driven at a scanning speed specified in the Y-axis direction.

Here, in practice, the reticle stage RST is a reticle coarse stage capable of driving the reticle base 36 on the reticle base 36 in a predetermined stroke range by a linear motor, and at least three voice coil motors with respect to the reticle coarse stage. The reticle fine motion stage capable of micro-driving in the X-axis direction, the Y-axis direction, and the θz direction by an actuator such as the above is illustrated. In FIG. 1 and FIG. 2, the reticle stage RST is shown as a single stage. Therefore, also in the following description, the reticle stage RST is a single stage capable of micro-driving in the X-axis direction, the Y-axis direction, and the θz direction and scanning driving in the Y-axis direction as described above by the reticle stage driver 12. It demonstrates as it.

The reticle stage RST has a movement stroke in the Y axis direction such that the entire surface of the reticle R can cross at least the optical axis AX of the projection optical system PL. In the case of the present embodiment, the movers of the linear motor described above are attached to the surfaces of one side and the other side of the reticle stage (RST) in the X axis direction (the front side and the inner side of the ground in Fig. 1), respectively, and correspond to these movers, respectively. The stators are respectively supported by a supporting member (not shown) formed separately from the body BD. For this reason, the reaction force acting on the stator of the linear motor at the time of driving the reticle stage RST is transmitted to the bottom surface F of the clean room via these supporting members. In addition, although the reticle stage drive part 12 is comprised including actuators, such as a linear motor and a voice coil motor as mentioned above, it is shown as a simple block in FIG. 1 for the convenience of illustration.

In addition, in this embodiment, the reaction frame structure which takes out reaction force through the support member formed separately from the body BD is employ | adopted, Such a structure is equivalent to Unexamined-Japanese-Patent No. 8-330224 and this, for example. As disclosed in US Patent No. 5,874,820, the disclosure of which is incorporated herein by reference in its publications and US patent applications as long as permitted by the national legislation of the designated or designated selected countries in this International Application.

However, not only the reaction frame structure but also the counter mass structure using the momentum conservation law having a counter mass that counteracts the reaction force when the reticle stage RST is moved may be adopted. The reaction force canceling mechanism using such a momentum conservation law is disclosed in detail in Japanese Unexamined Patent Publication No. Hei 8-63231 and US Pat. No. 6,255,796. In addition, as long as the national law of the designated country or selected country specified in the present international application permits, the above publication and the disclosure in the US patent are used as part of the description of the present specification.

The reticle laser interferometer (hereinafter referred to as a "reticle interferometer"; 13) as the first measurement system fixed to the reticle base 36 on the upper surface of the end portion of the Y axis direction-side (+ Y side) of the reticle stage RST. The moving mirror 15 reflecting the laser beam is fixed, and the position in the XY plane of the reticle stage RST (including the rotation in the θz direction, which is the rotational direction around the Z axis) is determined by the reticle interferometer 13, For example, it is always detected with a resolution of about 0.5 to 1 nm. Here, a pair of Y-axis moving mirrors 15y ₁ and 15y ₂ which are actually made of a hollow retro reflector at the end of the Y-axis direction (+ Y side) on the upper surface of the reticle stage RST as shown in FIG. 2. ) Is fixed at a predetermined interval in the X-axis direction, and the X-axis moving mirror 15x made of a planar mirror having a reflecting surface orthogonal to the X-axis direction at the end of the-side (+ X side) of the X-axis direction is It is fixed. In addition, the reticle Y interferometer 13y ₁ , 13y _{2 which} consists of a pair of laser interferometers as a pair of light interference interference measuring instruments which correspond to these moving mirrors 15y ₁ , 15y _2, and 15x individually, and a reticle X interferometer as a measuring device ( 13x) is formed. As described above, a plurality of reticle interferometers and moving mirrors are formed, respectively, but they are typically shown as moving mirrors 15 and reticle interferometers 13 in FIG. In addition, the moving mirrors 15x, 15y ₁ and 15y ₂ are formed in the reticle fine movement stage. For example, you may mirror-process the cross section of the + X side of the reticle stage RST, and may form a reflective surface (equivalent to the reflective surface of the moving mirror 15x).

As the said one reticle Y interferometer 13y ₁ , the laser interferometer of a single pass system is used. This reticle Y interferometer 13y ₁ is, for example, a two-frequency laser using a Zeman effect as a light source, and a heterodyne laser having a polarizing beam splitter, a quarter wave plate, a polarizer, a photoelectric conversion element, and the like. Interferometers are used. The two-frequency laser is, for example, different in frequency by 2 to 3 MHz, and also includes a laser light including two components orthogonal to each other in a polarization direction, and more specifically, a wavelength in two orthogonal polarization components, vertical and horizontal. Different, outputting a circular beam of Gaussian distribution. Of these, the vertical polarization component (V component) passes through the polarization beam splitter and becomes the measurement beam Ma passing through the measurement path, and the horizontal polarization component (H component) is reflected by the polarization beam splitter and passes through the reference path ( Ra) Of course, these measuring beams Ma and reference beams Ra are converted into circularly polarized light as they respectively pass through the quarter wave plate immediately before being emitted from the interferometer 13y ₁ . For example, as shown in FIG. 10A, the measuring beam Ma returns to the reticle Y interferometer 13y ₁ through the first reflecting surface of the moving mirror 15y ₁ and the second reflecting surface in order, and the internal optical system. And incident on the polarizer. On the other hand, the reference beam Ra passes through the first reflecting surface and the second reflecting surface of the reference mirror 14y ₁ made of a hollow retro reflector fixed to the barrel side of the projection optical system PL as shown in FIG. 2. It returns to the reticle Y interferometer 13y ₁ and injects into an internal optical system and a polarizer. In this case, the polarizer is set so that the polarization angle is 45 ° with respect to the H component and the V component, thereby interfering the interference light of the return beams of both components, that is, the measurement beam Ma and the reference beam Ra. It is given to a photoelectric conversion element. The photoelectric conversion element photoelectrically converts interfering light of both components and gives the signal (system) not shown the electric signal (interference signal). In this case, the phase of the measurement beam is Doppler shifted with respect to the phase of the reference beam due to the movement of the moving mirror 15y ₁ . Reference point, that is, moving mirror of precisely the mobile mirror (15y ₁₎ than; the signal processing system reference by heterodyne detection of the phase difference between the beam and the measuring beam, the moving mirror (15y ₁₎ the moving distance, that is, moving mirror (15y ₁ of It detects the position or change in position relative to the position of a reference mirror (14y ₁₎ of the vertex) of the hollow retro-reflector constituting the (15y _1). This signal processing uses a method well known for a heterodyne interferometer.

The other of the reticle Y interferometer (13y _2), the reticle Y interferometer (13y ₁₎ with the same configuration, and, the measuring beam (Mb), reference beam (Rb) from the interferometer (13y ₂₎ is shown in Fig. 2, respectively Irradiated to the moving mirror 15y ₂ and the reference mirror 14y ₂ each consisting of a hollow retro-reflector, and the interference signals of the reflected light (return light) are transmitted to the photoelectric conversion element inside the reticle Y interferometer 13y ₂ as described above. It is photoelectrically detected, and referred to by the signal processing system the beam and moved by heterodyne detection of the phase difference between the measuring beam mirror (15y _2; reference point of the more accurate is the moving mirror (15y _2), i.e. to configure a moving mirror (15y ₂₎ The position or positional change on the basis of the position of the reference mirror 14y ₂ of the hollow retro reflector apex is detected.

Therefore, the position of the reticle stage RST in the Y axis direction can be measured based on at least one of the measured values of the reticle Y interferometers 13y ₁ and 13y ₂ (for example, the average of both measured values, etc.) The rotation degree in the θz direction of the reticle stage RST can be measured (calculated) on the basis of the difference between and the distance between the measurement axes.

As the reticle X interferometer 13x, the same heterodyne interferometer as each of the interferometers 13y ₁ and 13y ₂ is used. The measurement beam and the reference beam from the reticle X interferometer 13x are irradiated to the X moving mirror 15x shown in FIG. 2 and the reference mirror 14x made of a planar mirror, respectively, and the interference signals of these reflected light (return light) In the same manner as described above, photodetection is performed by a photoelectric conversion element inside the reticle X interferometer 13x, and heterodyne detection of the phase difference between the reference beam and the measurement beam by a signal processing system is performed based on the position of the reference mirror 14x. Position or position change is to be detected. The position of the reticle stage RST in the X axis direction is measured based on the measured value of the reticle X interferometer 13x.

The position information of the reticle stage RST from the reticle Y interferometers 13y ₁ , 13y ₂ and the reticle X interferometer 13x described above is sent to the main controller 20, and the main controller 20 receives the reticle stage RST. The reticle stage RST is controlled through the reticle stage driver 12 based on the positional information of.

At the end of the upper surface of the reticle stage RST in the -Y direction, a fixed mark plate made of a glass material of the same material as the reticle, that is, a reticle physical mark (hereinafter referred to as a "reticle reference plate"; RFM) is in the X axis direction. It is installed along the extension. On this reticle reference plate RFM, as shown in FIG. 2, at least at a predetermined pitch along the X-axis direction at positions substantially opposite to the pair of Y-axis moving mirrors 15y ₁ and 15y ₂ described above, respectively. Each of the three reference mark sets is formed. In this embodiment, as shown in FIG. 3B, it is assumed that it is arrange | positioned five in each area | region of + X side and -X side of reticle reference plate RFM, for example. Specifically, the measurement marks RM _{11 to} RM ₁₅ are arranged in the + X side area, and the measurement marks RM _{21 to} RM ₂₅ are arranged in the -X side area. Cross marks are used as the measurement marks (RM _{11 to} RM ₁₅ and RM _{21 to} RM ₂₅ ). In this case, the pitch p between the reference marks is, for example, about 100 μm to about 1 mm, and the interval 4D between the measurement marks RM _1i and RM _2i (i = 1 to 5) paired with each other is For example, it shall be about 100-150 mm.

The projection optical system PL is held in the first column 32 constituting the body BD under the reticle stage RST in FIG. 1. Here, the structure of the body BD is demonstrated.

The body BD is equipped with the 1st column 32 provided on the bottom surface (or upper surface of frame) F of a clean room, and the 2nd column 34 mounted in the upper surface of this 1st column 32. As shown in FIG. Doing. The first column 32 includes three leg portions 37A to 37C; however, the leg portion 37C on the inner side of the paper shown in FIG. 1 is not shown, and the upper surface of these leg portions 37A to 37C is the same. It is connected to the lower end surface, and the barrel base plate 38 which comprises the ceiling part of the 1st column 32 is provided.

Each leg 37A-37C is equipped with the dustproof unit 39 provided in the bottom surface, and the support | pillar 40 fixed to the upper part of this dustproof unit 39. As shown in FIG. The microvibration from the bottom surface F is insulated by the micro G level by each dustproof unit 39, and is hardly transmitted to the barrel surface plate 38. The cylindrical surface plate 38 has a circular opening (not shown) at its nearly center portion, and the projection optical system PL is inserted from above with the optical axis AX in the Z-axis direction.

The flange FLG is formed in the barrel of the projection optical system PL, and the projection optical system PL is supported by the barrel plate 38 through the flange FLG. On the upper surface of the barrel surface plate 38, for example, the lower end of the three legs 41A to 41C (not shown in Fig. 1 as the legs 41C in the drawing) is located at the position surrounding the projection optical system PL. It is fixed and the reticle base 36 mentioned above is mounted on the upper parts of these legs 41A-41C, and is supported horizontally. That is, the 2nd column 34 is comprised by the reticle base 36 and the three legs 41A-41C which support this.

As the projection optical system PL, a refraction optical system composed of a plurality of lens elements arranged at predetermined intervals along the optical axis AX direction is used as a reduction system that is both telecentric. As this projection optical system PL, a reduction optical system of 1/4 is used as the projection magnification β as an example. For this reason, when the slit-shaped illumination area IAR on the reticle R is illuminated by the illumination light IL from the illumination system 10, the slit illumination area by the illumination light IL which has passed through this reticle R. An exposure area in which the reduced image (partially inverted image) through the projection optical system PL of the circuit pattern of the reticle R in the IAR is conjugated to the illumination area IAR on the wafer W on which the photoresist is applied to the surface. It is formed in (IA).

The wafer stage WST is actually configured to include an XY stage moving in an XY two-dimensional plane and a wafer table mounted on the XY stage. In this case, the XY stage is freely driven along the upper surface of the stage base 16 in the XY two-dimensional plane (including? Z rotation) by a drive system (not shown) such as a linear motor or a planar motor.

The wafer table is inclined with respect to the optical axis (AX) direction (Z axis direction) and the plane (XY plane) perpendicular to the optical axis by a drive system (not shown) including an actuator such as a voice coil motor disposed on the XY stage, That is, it is driven in the θx direction, which is the rotational direction around the X axis, and in the θy direction, which is the rotational direction around the Y axis.

On the wafer table, the wafer W is held by vacuum suction (or electrostatic suction) through a wafer holder (not shown).

In this manner, the wafer stage WST actually includes a plurality of components, but for convenience, the wafer stage WST is described below by the wafer stage driver 28 controlled by the main controller 20 for convenience. It will be described as being a single stage which is freely driven in the six degrees of freedom directions of Z, θx, θy, and θz. In addition, although the wafer stage drive part 28 is comprised including a linear motor, a planar motor, a voice coil motor, etc., it is shown in FIG. 1 as a simple block for the convenience of illustration. Further, for example, the wafer stage WST may be a fine-grained stage by allowing the wafer table to be microscopically movable at least in the X-axis and Y-axis directions with respect to the XY stage.

The stage base 16 is also called a surface plate. In the present embodiment, the stage base 16 is provided on the bottom surface F via a plurality of vibration isolation units 43. That is, the stage base 16 has a structure separate from the body BD holding the projection optical system PL and the like.

On the wafer stage WST (exactly a wafer table), a moving mirror 27 reflecting a laser beam from a wafer laser interferometer (hereinafter referred to as "wafer interferometer") 31 as a second measurement system is fixed, and the body BD ), The position in the XY plane of the wafer stage WST is always detected at a resolution of, for example, about 0.5 to 1 nm.

Here, in practice, on the wafer stage WST (exactly the above-described wafer table), a moving mirror having a reflective surface orthogonal to the Y-axis direction in the scanning direction at the time of scanning exposure and a reflective surface orthogonal to the X-axis direction in the non-scanning direction Although a moving mirror having a shape is formed, the laser interferometer also has an X laser interferometer for measuring X-axis position and a Y laser interferometer for measuring Y-axis direction in correspondence thereto, but in FIG. , A wafer interferometer 31 is shown. For example, you may mirror-process the cross section of the wafer stage WST, and may form a reflecting surface (corresponding to the reflecting surface of the moving mirror 27). In addition, the X laser interferometer and the Y laser interferometer are multi-axis interferometers having a plurality of side axes, and in addition to the X and Y positions of the wafer table, rotation (yawing (θz rotation, which is rotation around the Z axis), pitching (θx which is rotation around the X axis) Rotation) and rolling (θy rotation which is rotation around the Y axis) can also be measured. Therefore, in the following description, it is assumed that the wafer interferometer 31 measures the positions of five degrees of freedom of X, Y, θz, θy, and θx of the wafer stage WST. Moreover, a multi-axis interferometer irradiates a laser beam to the reflecting surface which is not shown in the body BD with which the projection optical system PL is mounted through the reflecting surface which is inclined 45 degrees, and is installed in the wafer stage WST, and a projection optical system The relative positional information regarding the optical axis direction (Z-axis direction) of the PL may be detected.

The position information (or speed information) of the wafer stage WST is sent to the main controller 20, and the main controller 20 carries out a wafer stage driver 28 (not shown) based on the position information (or speed information). The wafer stage WST is controlled through this.

The reference mark plate FM is fixed on the wafer stage WST. The surface of this reference mark plate FM is substantially the same height as the surface of the wafer W held on the wafer stage WST. On the surface of the reference mark plate FM, a pair of reference marks WM1 and WM2 corresponding to the measurement marks RM _{11 to} RM ₁₅ and RM _{21 to} RM ₂₅ described above, for baseline measurement of the alignment system described later. A plurality of reference marks, including reference marks, are formed. The reference marks WM ₁ and WM ₂ are arranged on the reference mark plate FM, arranged in the X-axis direction at intervals D, as shown in FIG. 3A. As these reference marks WM ₁ and WM ₂ , box marks are used here. In addition, at least a part of these many reference marks may be directly formed on the wafer stage (WST; for example, wafer table).

Above the reticle stage RST, for example, as disclosed in detail in Japanese Patent Application Laid-open No. Hei 7-176468 and US Pat. No. 5,646,413 and the like, an imaging device such as a CCD is exposed. A pair of reticle alignment systems RA ₁ , RA ₂ of the image processing method which uses light of wavelength (illumination light IL in this embodiment) as alignment illumination light; in FIG. 1, the reticle alignment system RA ₂ on the inner side of the paper is 2, the pair of reticle alignment systems RA ₁ and RA ₂ are symmetrical (left-right symmetry) with respect to the YZ plane including the optical axis AX of the projection optical system PL. In addition, the pair of reticle alignment systems RA ₁ and RA ₂ have a structure capable of reciprocating in the X-axis direction within the XZ plane passing through the optical axis AX. Designated country designated in the application; or As part of the description herein, reference is made to the disclosure in the above publication and the corresponding US patent to the extent permitted by the national legislation of the selected country.

Normally, a pair of reticle alignment systems RA ₁ , RA ₂ is a pair of reticle alignments arranged outside the light shield of the reticle R with the reticle R mounted on the reticle stage RST. It is set in the position which can respectively observe a mark. The pair of reticle alignment marks are arranged at intervals 4D in the X axis direction.

In addition, in the exposure apparatus 100 of this embodiment, although not shown, it has a light source which is controlled on and off by the main controller 20, and is arranged in the optical axis AX direction (Z-axis direction) of the wafer W. A multi-point focal position detection system (hereinafter referred to as a "multi-point AF system") of an inclined incidence system that detects a relative position and an inclination with respect to the XY plane is formed. The multi-point AF system similar to the multi-point AF system of the present embodiment is disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 6-283403, US Patent No. 5,448,332 and the like.

In addition, in the main controller 20, in addition to the movement in the Z-axis direction of the wafer stage WST via the wafer stage driver 28 based on the focus signal FS from the multi-point AF system during scanning exposure described later or the like. The irradiation area of the illumination light IL (illumination area IAR) and the two-dimensional inclination (that is, rotation in the θx and θy directions) are also controlled, that is, by controlling the movement of the wafer stage WST using a multi-point AF system. In the conjugated region), autofocus (autofocusing) and autoleveling are performed to substantially match the imaging surface of the projection optical system PL with the surface of the wafer W. FIG. The disclosures in the above publications and US patents are incorporated by reference herein as long as the national legislation of the designated country or selected country specified in this international application permits.

In the exposure apparatus of the present embodiment, although not shown, an off-axis alignment system for detecting an alignment mark (positioning mark) on the wafer W, a reference mark on the reference mark plate FM, and the like is a projection optical system PL. It is arranged on the side of the barrel. In this alignment system, the target mark is irradiated to the target mark, which is a broadband detection light that does not expose the resist on the wafer W, for example, and the image of the target mark formed on the light receiving surface by the reflected light from the target mark is not shown. An image processing method FIA (Field Image Alignment) sensor is used which image | photographs the image | index of the index | index which is not, using an imaging device (CCD etc.), and outputs these imaging signals. In addition to the FIA system, coherent detection light is irradiated to the target mark to detect scattered light or diffracted light generated from the target mark, or two diffracted light generated from the target mark (for example, It is, of course, possible to use an alignment sensor that detects interference by the same order) alone or in combination as appropriate.

The main controller 20 is composed of a workstation (or a microcomputer) or the like, and the main controller 20 is a storage device 51 made of a hard disk or the like and pointing to a keyboard, a mouse, etc. as shown in FIG. An input / output device 30 including a device and a display such as a CRT or a liquid crystal panel is provided. In the storage device 51, the positional relationship between the optical axes of the measurement beams Ma and Mb of each of the reticle Y interferometers 13y ₁ and 13y ₂ described above and the reference axes Ra and Rb corresponding to these individually The correlation information indicating the relationship between the position measurement error of the reference point of the moving mirrors 15y ₁ and 15y ₂ at least and the position of the reticle stage RST relative to the non-scanning direction corresponding thereto is stored.

Here, the method of creating this correlation information will be described with reference to another diagram according to the flowchart of Fig. 4 showing the processing algorithm of the main controller 20 (internal CPU).

This flowchart of FIG. 4 (corresponding processing algorithm) starts when an instruction for starting measurement is input by the operator via the input / output device 30.

First, in step 102, the counter n indicating the mark number of the pair of measurement marks to be measured is initialized to 1 (n ← 1).

In the next step 104, the wafer stage driver 28 is controlled based on the design values of the pair of reference marks WM ₁ and WM ₂ while monitoring the measured values of the wafer interferometer 31, and the wafer stage WST is measured. Move to. Here, the measurement position is a position where the midpoint between the pair of reference marks WM ₁ and WM ₂ substantially coincides with the optical axis of the projection optical system PL, and the pair of reticle alignment systems RA ₁ and RA ₂ described above. Is the position where the reference marks WM ₁ , WM ₂ are located within the detection field of the reticle alignment system RA ₁ , RA ₂ when is at the normal position.

In the next step 106, while maintaining the measured values of the pair of reticle Y interferometers 13y ₁ and 13y ₂ , the rotational error of the reticle stage RST is maintained at 0, and the position (Y position) in the Y axis direction is determined. Based on the measurement of the reticle X interferometer 13x while maintaining its position, a pair of measurement marks (RM _1n , RM _2n ; in this case RM ₁₁ , RM ₂₁ ) of the nth (in this case, the first) is the reticle alignment system (RA _The reticle stage RST is moved through the reticle stage driver 12 so as to be located within the detection field of ₁ , RA ₂ ).

In the next step 108, the pair of measurement marks (RM _1n , RM _2n ; in this case RM ₁₁ , RM ₂₁ ) using a pair of reticle alignment systems (RA ₁ , RA ₂ ), corresponds to the reference marks (WM ₁ , Simultaneously measure the image of WM ₂ ). In this case, the image RM _1n ′ of the measurement mark RM _1n and the image WM ₁ ′ of the reference mark WM ₁ are simultaneously measured by the reticle alignment system RA ₁ , and the measurement mark RM _2n The image RM _2n ′ and the image WM ₂ ′ of the reference mark WM ₂ are simultaneously measured in the reticle alignment system RA ₂ . Here, as an example, the image RM ₁₁ ′ of the measurement mark RM ₁₁ and the image WM ₁ ′ of the reference mark WM ₁ shown in FIG. 5A are measured by the reticle alignment system RA ₁ , and FIG. 5B. The image RM ₂₁ ′ of the measurement mark RM ₂₁ shown in the figure and the image WM ₂ ′ of the reference mark WM ₂ are measured by the reticle alignment system RA ₂ .

In the next step 110, the position displacement image of the (Δy _1n) and the reference mark of the "image of the measuring mark of the (RM _1n image (WM _1), of the reference mark) based on the measurement result of step 108 (WM ₂ The position shift amount [Delta] _2n of the image _RM2n 'of the measurement mark with respect to') is calculated and the calculation result is stored in a memory such as RAM. In this case, Δy ₁₁ of FIG. 5A and Δy ₂₁ of FIG. 5B are calculated.

In the next step 112, the point corresponding to the point _{P 1n (Δy 1n, X n} ) and the position displacement (Δy _2n) corresponding to the, position displacement (Δy _1n) calculated in the step 110 P _2n (Δy _2n, x _n ) is plotted on the coordinate system whose horizontal axis is the position (X position) in the X axis direction of the reticle stage RST. In this case, a point P ₂₁ is plotted on the coordinate system a point P shown in Fig. _11, Fig. 6B in the coordinate system shown in Fig. 6A.

In the next step 114, it is determined whether or not the count value n of the counter n is equal to or larger than N (here, N = 5), which is 1/2 of the total number of marks to be measured. Increment counter n by one (n ← n + 1). Thereafter, the process returns to step 106, and the loop processing of steps 106 → 108 → 110 → 112 → 114 → 116 is repeated until the judgment in step 114 is affirmed. Thereby, the following processes are performed when n = 2-5 each.

<when n = 2>

In this case, in step 108, the image RM ₁₂ ′ of the measurement mark RM ₁₂ and the image WM ₁ ′ of the reference mark WM ₁ shown in FIG. 5C are measured by the reticle alignment system RA ₁ , The image RM ₂₂ ′ of the measurement mark RM ₂₂ and the image WM ₂ ′ of the reference mark WM ₂ shown in FIG. 5D are measured by the reticle alignment system RA ₂ . In step 110, Δy ₁₂ of FIG. 5C and Δy ₂₂ of FIG. 5D are calculated. In the step 112, the point P ₁₂ to the coordinate system shown in Figure 6A, are each plotted point P ₂₂ to the coordinate system shown in Figure 6B.

<when n = 3>

In this case, the image RM ₁₃ ′ of the measurement mark RM ₁₃ and the image WM ₁ ′ of the reference mark WM ₁ , shown in FIG. 5E in step 108, are measured by the reticle alignment system RA ₁ , The image RM ₂₃ ′ of the measurement mark RM ₂₃ shown in FIG. 5F and the image WM ₂ ′ of the reference mark WM ₂ are measured by the reticle alignment system RA ₂ . In step 110, Δy ₁₃ in FIG. 5E and Δy ₂₃ in FIG. 5F are calculated. In step 112, the point P ₁₃ on the coordinate system shown in Figure 6A, respectively, the point P ₂₃ plotted in the coordinate system shown in Figure 6B.

<when n = 4>

In this case, the image RM ₁₄ ′ of the measurement mark RM ₁₄ and the image WM ₁ ′ of the reference mark WM ₁ , shown in FIG. 5G in step 108, are measured by the reticle alignment system RA ₁ , The image RM ₂₄ ′ of the measurement mark RM ₂₄ and the image WM ₂ ′ of the reference mark WM ₂ shown in FIG. 5H are measured by the reticle alignment system RA ₂ . In step 110, Δy ₁₄ of FIG. 5G and Δy ₂₄ of FIG. 5H are calculated. In the step 112, the point P ₁₄ to the coordinate system shown in Figure 6A, are each plotted point P ₂₄ to the coordinate system shown in Figure 6B.

<when n = N = 5>

In this case, in step 108, the image RM ₁₅ ′ of the measurement mark RM ₁₅ and the image WM ₁ ′ of the reference mark WM ₁ , shown in FIG. 5I, are measured by the reticle alignment system RA ₁ , The image RM ₂₅ ′ of the measurement mark RM ₂₅ and the image WM ₂ ′ of the reference mark WM ₂ shown in FIG. 5J are measured by the reticle alignment system RA ₂ . In step 110, Δy ₁₅ of FIG. 5I and Δy ₂₅ of FIG. 5J are calculated. In the step 112, the point P ₁₅ to the coordinate system shown in Figure 6A, are each plotted point P ₂₅ to the coordinate system shown in Figure 6B.

In this way, when the process of step 112 ends when n = N = 5, the judgment in step 114 is affirmed, and the process proceeds to step 118. In this step 118, approximation curves y = f ₁ (x), y = f ₂ (x) by statistical operations, e.g. least squares operations, using discrete points P _{11 to} P ₁₅ and P _{21 to} P ₂₅ respectively. And each are stored in a memory such as a RAM or a storage device 51 as the above-mentioned correlation information, and then a series of processes of this routine are ended. In this result, the curve y = f ₁ (x) in 6A and y = f ₂ (x) in FIG. 6B are also stored. As the statistical operation, instead of the least square operation, a function may be obtained by continuously interpolating the above-described discrete data by a suitable interpolation operation, for example, the spline method, and the function may be used as the correlation information.

In addition to the above functions, for example, in each case of n = 1 to n = N, in step 112, the coordinate values of the points P _1n and P _2n are sequentially stored in a memory such as RAM. The table data (correction map) may be created, and the table data may be used as the correlation information.

The correlation information (function y = f ₁ (x), y = f ₂ (x) or correction map) created as described above is stored in the storage device 51 of FIG.

As can be seen from the description of the above-described process of creating correlation information, the correlation information (function y = f ₁ (x), y = f ₂ (x) or correction map) is a reticle Y interferometer 13y ₁ , 13y. ₂ ) It must be the information of each measurement error. The reason for this is that the mark measurement is based on the measured values of the reticle Y interferometers 13y ₁ , 13y ₂ , that is, the measured values are trusted and the Y position of the reticle stage RST is maintained at a predetermined value in the X axis direction. position displacement in the Y-axis direction with respect to the pitch (p) corresponds to the reference mark (WM _1, WM ₂₎ of step, the pair of measuring mark (RM _1n, RM _2n) for each step position to move up (Δy _1n, Δy _2n ) is measured. In this case, if there are no measurement errors in the reticle Y interferometers 13y ₁ and 13y ₂ , the center of the measurement mark RM _1n and the center of the reference mark WM ₁ coincide, and the measurement mark (RM _2n ). The center of the coincidence coincides with the center of the reference mark WM ₂ , and the positional shift amounts? _{Y 1n} and? Y _2n are both zero. However, in reality, a reticle Y interferometer (13y _1, 13y ₂₎ the peak position of each of the measurement error minute by each reticle Y measurement reference points, the present embodiment of the mobile mirror (15y _1, 15y ₂₎ according to the measurement beam of the interferometer As a result of the positional position of the reticle stage RST being changed from the ideal state so that the position is shifted in the Y-axis direction (in this case, the reticle stage RST has a θz rotational error), the positional displacement amount 13y ₁ , 13y ₂ This is because it is being measured.

Next, operation | movement of the exposure process in the exposure apparatus 100 of this embodiment is demonstrated easily.

First, the reticle R is conveyed to the reticle conveying system which is not shown in figure, and it is adsorbed-held by the reticle stage RST in a loading position. Subsequently, the positions of the wafer stage WST and the reticle stage RST are controlled by the main controller 20 so that the at least one pair of reticle alignment marks formed on the reticle R correspond to the reference mark plate FM. The relative position measurement with the reference mark for reticle alignment is performed by the pair of reticle alignment systems RA ₁ and RA ₂ described above, and is defined by the side axis of the reticle interferometer 13 based on the result of the relative position measurement. Calculation of the relationship between the reticle stage coordinate system and the wafer stage coordinate system defined by the long axis of the wafer interferometer 31, that is, reticle alignment is performed.

Next, the main stage apparatus 20 moves the wafer stage WST so that the reference mark plate FM is located directly below the off-axis alignment system, and the detection center of the alignment system and the base on the reference mark plate FM are moved. The line mark reference mark and the positional relationship are measured. In the main control unit 20, the positional relationship, the positional relationship between the pair of reticle alignment marks and the reference marks corresponding to the previous reticle alignment, and the measured values of the wafer interferometer 31 at the time of measuring the respective positional relationships The relationship between the baseline of the alignment system, that is, the projection position of the reticle pattern and the detection center of the alignment system is obtained. The reticle alignment, baseline measurement, and the like are disclosed in detail in, for example, Japanese Patent Application Laid-Open No. 7-176468 and US Pat. No. 5,646,413 corresponding thereto.

When the above-described baseline measurement is completed, the EGA (Enhanced Global Alignment) method disclosed in detail by, for example, Japanese Laid-Open Patent Publication No. 61-44429, US Pat. No. 4,780,617, and the like, by the main controller 20. Wafer alignment such as or the like is performed, and the positions of all shot regions on the wafer W are obtained. The disclosures in the above publications and US patents are incorporated by reference herein as long as the national legislation of the designated country or selected country specified in this international application permits.

Subsequently, in the main controller 20, the wafer stage WST is first shot while monitoring the position information from the interferometers 31 and 13 based on the positional information and baseline of each shot region on the wafer W obtained above. The reticle stage RST is moved to the scanning start position and the scanning exposure of the first shot region is started while moving to the scanning starting position (acceleration starting position) for exposing the region. Here, the main controller 20 stores the X position information and the memory of the reticle stage RST measured by the reticle interferometer 13 (more accurately, the reticle X interferometer 13x) when the reticle stage RST is moved to the scanning start position. The measured values of the reticle Y interferometers 13y ₁ , 13y ₂ are corrected based on the correlation information (y = f ₁ (x), y = f ₂ (x)) described above stored in the device 51. As a result, when the values (correction values) of measurement errors of the reticle Y interferometers 13y ₁ and 13y ₂ are different, the θz rotation of the reticle stage RST is also corrected.

In the main control unit 20, when the reticle stage RST and the wafer stage WST start the relative scanning in the opposite directions in the Y-axis direction, when both stages RST and WST reach their respective target scanning speeds, the illumination light IL By this, the pattern region of the reticle R starts to be illuminated, and scanning exposure is started. Although the light emission of the light source is disclosed prior to the start of the scanning exposure, since the movement of each blade of the movable blind constituting the reticle blind is controlled in synchronism with the movement of the reticle stage RST by the main controller 20, the reticle Irradiation of the illumination light IL out of the pattern region on (R) is the same as that of a normal scanning stepper.

In the main control unit 20, the moving speed Vr of the reticle stage RST in the Y-axis direction and the moving speed Vw of the wafer stage WST in the X-axis direction are particularly the projection optical system PL during the scanning exposure. The reticle stage RST and the wafer stage WST are synchronously controlled so as to be maintained at a speed ratio in accordance with the projection magnification? In the main controller 20, the reticle stage RST measured by the reticle interferometer 13 (more precisely the reticle X interferometer 13x) as described above also during the synchronous control of the reticle stage RST and the wafer stage WST. The measured values of the reticle Y interferometers 13y ₁ , 13y ₂ based on the X position information of and the above-described correlation information (y = f ₁ (x), y = f ₂ (x)) stored in the storage device 51. Calibrate

Then, the region in which the pattern region of the reticle R is different is gradually illuminated with ultraviolet pulse light, and the illumination of the entire surface of the pattern region is completed, so that the scanning exposure of the first shot region on the wafer W is terminated. As a result, the circuit pattern of the reticle R is reduced and transferred to the first shot region through the projection optical system PL. In addition, the above-mentioned autofocus and autoleveling are performed by the main controller 20 using the above-mentioned multipoint AF system during the scanning exposure.

In this way, when the scanning exposure of the first shot region is completed, an inter-shot stepping operation is performed in which the wafer stage WST is moved to the scanning start position (acceleration start position) for exposing the second shot region. Then, the scanning exposure of the second shot region is performed as described above. Thereafter, the same operation is performed after the third short region.

In this way, the stepping operation between the shots and the scanning exposure operation of the shots are repeated, and the pattern of the reticle R is transferred to all the shot regions on the wafer W in a step-and-scan manner.

In the exposure apparatus 100 of the present embodiment, the above-described process of creating correlation information (processes in steps 102 to 118 in FIG. 4) is repeated at a predetermined timing, for example, by an operator's instruction, and each time a step is performed. The correlation information in the storage device may be updated using f ₁ (x) and f ₂ (x) calculated in 118. In this way, even if the measurement error of the reticle Y interferometer fluctuates over time by some factor, it becomes possible to precisely position-control the reticle stage RST always without being affected by it.

As can be seen from the description so far, in the present embodiment, a drive system for driving the reticle stage RST and the wafer stage WST in the scanning direction is constituted by the reticle stage driver 12 and the wafer stage driver 28. It is. Moreover, the control apparatus is comprised by the main control apparatus 20. As shown in FIG.

As described above, according to the exposure apparatus 100 of the present embodiment, in the position measurement of the reticle stage RST, the main controller 20 is a pair of Y-axis moving mirrors 15y ₁ on the reticle stage RST. , 15y ₂₎ the measuring beam (Ma, Mb) to investigate and the reticle Y interferometer for receiving in the reflected light (13y _1, 13y ₂₎ and outputs the Y-axis direction of the reticle stage (RST) based on the (first axis direction in ), And the positional information about the X axis direction (second axis direction) of the reticle stage RST is measured using a reticle X interferometer 13x serving as the second axis direction position measuring device. Subsequently, the main control unit 20 stores the optical axis of the measurement beams Ma and Mb of the reticle Y interferometers 13y ₁ and 13y ₂ and the optical axis of the reference beam Ra.Rb stored in the storage device 51. Position measurement error of the reference point (mentioned vertex position) on the reflecting surface of the Y-axis moving mirror 15y ₁ , 15y ₂ due to the positional relationship and wavefront aberration of the beams Ma, Mb and Ra, Rb and the corresponding Correlation information (function y = f ₁ (x), y = f ₂ (x), etc.) indicating the relationship with the position of the reticle stage (RST) in the X axis direction, and the X axis of the measured reticle stage (RST) Based on the positional information about the direction, the positional information in the Y-axis direction and θz direction of the reticle stage RST, in which measurement errors of the reticle Y interferometers 13y ₁ and 13y ₂ are corrected, is calculated. As a result, the position measurement error in the Y-axis direction and θz direction of the reticle stage RST due to the interaction between the work-off due to the optical axis shift of the reticle Y interferometers 13y ₁ and 13y ₂ and the beam wavefront aberration is adjusted. The positional information corrected according to the position in the X-axis direction of RST) can be obtained. Therefore, the positional information in the Y-axis direction and θz direction of the reticle stage RST can be accurately measured using an optical interference measuring instrument such as the reticle Y interferometers 13y ₁ and 13y ₂ .

In addition, in the exposure apparatus 100 of the present embodiment, the main controller 20 preliminarily performs the processing according to the flowchart of FIG. 4 to obtain the above-described correlation information by actual measurement, and the information is stored in the storage device 51. I remember it. For this reason, by using the correlation information in this storage device 51 to control the position of the reticle stage RST as described above, the reticle Y interferometers 13y ₁ , 13y ₂ , including a moving mirror and a fixed mirror are included. High-precision position control based on the positional information which collectively corrects the influence of the manufacturing error and adjustment error (including the mounting error) of each component of the measurement system can be performed.

Moreover, according to the exposure apparatus 100 of this embodiment, the positional information regarding the Y-axis direction (and (theta) z direction) of the reticle stage RST is converted into the reticle Y interferometer 13y ₁ , 13y ₂ by the position measuring method mentioned above. Can be measured with high accuracy. Then, since the main controller 20 controls the position of the Y axis direction (first axis direction) of the reticle stage RST based on the position information accurately measured, the Y axis direction of the reticle stage RST ( The position of the scanning direction) can be controlled with high accuracy.

According to the exposure apparatus 100 of the present embodiment, when scanning exposure, the main controller 20 uses the reticle (based on the measurement results of the reticle Y interferometers 13y ₁ and 13y ₂ and the reticle X interferometer 13x). R) The position of the reticle stage (RST) on which the reticle stage (RST) is mounted is measured on the Y-axis direction (scanning direction) and the X-axis direction (non-scanning direction) while the wafer W is based on the measurement result of the wafer interferometer 31. The positional information regarding at least 5 degree of freedom directions including the Y axis, the X axis, and the θz direction of the wafer stage WST on which the is mounted is measured. Then, the main controller 20 reticle Y interferometer 13y ₁ , 13y for the reticle stage RST based on the measurement result of the positional information in the X-axis direction and the above-described correlation information stored in the storage device 51. ₂ ) obtain the positional information about the Y-axis direction (and θz direction) of the first stage which corrected the measurement error due to, and the positional information about the Y-axis direction (and θz direction) of the reticle stage RST after the correction; The reticle stage RST and the wafer stage WST are controlled based on the positional information about at least five degrees of freedom including the Y axis, the X axis, and the θz direction of the wafer stage WST.

Therefore, the main control unit 20 performs the synchronous control of the reticle stage RST and the wafer stage WST, that is, the synchronous control of the reticle R and the wafer W with high accuracy, and thereby the reticle R and the wafer It is possible to improve the synchronization accuracy of the (W), shorten the synchronization correction time, and the like, and to realize high-precision exposure by the scanning exposure method, thereby accurately transferring the pattern of the reticle R to each shot region on the wafer W with high accuracy. It becomes possible.

In the above embodiment, since a pair of Y interferometers 13y ₁ and 13y ₂ are used for position measurement in the Y axis direction of the reticle stage RST, position information in the θz direction in addition to the Y axis direction is inevitable. Can be obtained with high accuracy, but the present invention is not limited to this, and when only one interferometer for position measurement in the Y axis direction of the reticle stage RST is used, the position information in the Y axis direction of the reticle stage RST is as described above. Only with good precision. In addition, at least one of the Y interferometers 13y ₁ and 13y ₂ for position measurement in the Y axis direction of the reticle stage RST is constituted by a biaxial interferometer having two axes of side axes, and the measurement beams of each side axis are In the case of adopting a configuration in which the corresponding moving mirror is incident on different Z positions, the positional information in the θx direction (the pitching direction), which is the rotational direction around the X axis, can be measured with high accuracy in addition to the Y and θz directions. Become.

Moreover, in the said embodiment, the position of the vertex (reference point on a reflecting surface) of the moving mirrors 15y ₁ and 15y ₂ by measuring the position shift amount of the measurement mark on the reticle stage RST and the reference mark on the reference plate FM. The measurement error is calculated, but not limited thereto. The reticle X interferometer (13x) is maintained based on the measured values of the reticle Y interferometers (13y ₁ , 13y ₂ ) while maintaining the Y-direction position of the reticle stage (RST) at a predetermined coordinate position. Steps of moving the reticle stage (RST) to a plurality of positions in the X-axis direction using the measured values of, and calculating the position measurement error of the vertices (reference points on the reflecting surface) of the moving mirrors (15y ₁ , 15y ₂ ) for each step position If so, the measuring method or calculating method of the position error may be any method. For example, the wavefront aberrations of the measurement beam and the reference beam are measured in advance, and the optical axis shift amounts of the beams are calculated (inferred) from the relationship described in FIG. 10A and FIG. The above-described measurement error δL (= ΔL1-ΔL2) may be calculated by calculation based on the wavefront aberration (see FIGS. 10A and 10B). Regardless of which method is used, the correlation information may be prepared as described above based on the position measurement error obtained for each step position.

In the above embodiment, in the case of creating the table data (correction map) instead of the function data (y = f ₁ (x), y = f ₂ (x)) as the correlation information, in the main controller 20, When actually measuring the position of the reticle stage RST, a predetermined interpolation operation is performed to calculate the position measurement error (discrete data) for each step position in the correction map according to the positional information about the measured X axis direction of the reticle stage RST. By using the calculation result interpolated by, the measurement error of the reticle Y interferometers 13y ₁ , 13y ₂ at the X position may be calculated, and in this case, the calculated position information whose calculation error is corrected is calculated. Just do it.

In the above embodiment, the main controller 20 corrects the measured values of the reticle Y interferometers 13y ₁ , 13y ₂ (that is, the position in the scanning direction and the amount of rotation in the θz direction) based on the correlation information described above. Although the position and rotation of the scanning direction of the reticle stage RST are controlled based on this correction value, it is not limited to this, and the main control unit 20 uses the reticle Y interferometers 13y ₁ , 13y ₂ in the scanning direction. Wafer stage instead of or in combination with the reticle stage RST in order to correct the relative positional error of the reticle R and the wafer W that occur due to a measurement error with respect to at least one of the position and the amount of rotation in the θz direction. You may control the position and rotation of the scanning direction of WST using the above-mentioned correlation information and the positional information regarding the non-scanning direction of the reticle stage RST. The main controller 20 also uses the above-described correlation information and positional information about the non-scanning direction of the reticle stage RST without correcting the measured values of the reticle Y interferometers 13y ₁ and 13y ₂ . In this case, the reticle stage (RST) and the reticle stage (RST) and the relative error between the reticle (R) and the wafer (W) caused by the measurement error are almost zero. What is necessary is just to control at least one of the position and rotation in at least one of the wafer stages WST. Then, the main controller 20 carries out the scanning direction (Y axis direction) in at least one of the reticle stage RST and the wafer stage WST based on the correlation information and the positional information about the non-scanning direction of the reticle stage RST. The target positional information regarding the step S) may be corrected, and the movement of at least one stage may be controlled so that the corrected target positional information and the measured value of the Y interferometer are substantially identical.

In the above embodiment, when the correlation information or table data or the like described above is generated, the n reticle stages RM _1n and RM _2n are respectively detected by the pair of reticle alignment systems RA ₁ and RA ₂ . RST) is moved in the X-axis direction, but when the measurement marks RM _1n and RM _2n are detected, the reticle stage RST is continuously moved without detecting (stopping) the reticle stage RST. You may also

In the above embodiment, the reticle stage RST is based on the measurement values of the reticle Y interferometers 13y ₁ and 13y ₂ when the measurement marks RM _1n and RM _2n are detected by the reticle alignment systems RA ₁ and RA ₂ . Although the position in the Y-axis direction of () is kept at a predetermined coordinate position, it is not necessary to maintain the position in the Y-axis direction of the reticle stage RST at the predetermined coordinate position during this movement. In this case, for example, the reticle alignment is based on the measured values of the reticle Y interferometers 13y ₁ and 13y ₂ obtained when the measurement marks RM _1n and RM _2n are detected by the reticle alignment systems RA ₁ and RA ₂ . By correcting the detection results of the systems RA ₁ and RA ₂ (position displacement amounts Δy _1n and Δy _2n described above), the influence of the positional shift and rotation amount (yaw amount) in the Y axis direction of the reticle stage RST is excluded. The correlation information, table data and the like described above may be calculated using the correction value.

In the above embodiment, the installation error and manufacturing error of the reticle reference plate (RFM) or reference mark plate (FM) and manufacturing error (i.e., measurement marks (RM _1n , RM _2n )) at the time of preparing the correlation information or table data described above. Although the error regarding the position where the reference marks WM1 and WM2 are formed) is not taken into consideration, the above-described correlation information or the like may be calculated using at least one of these errors. In addition, when these errors fluctuate over time due to vibration, heat, or the like, the error information is periodically updated or calculated by calculation or simulation, or the measurement is periodically performed. At least one position control of the reticle stage RST and the wafer stage WST may be performed.

Further, in the above embodiments, a reticle Y interferometer (13y _1, 13y ₂₎ move the mirror (15y _1, 15y _2), measured beam is irradiated from a has been described on the case of forming a hollow retro-reflector, this wave front aberration The measurement error can be corrected even when the hollow retro reflector tends to be relatively large due to the interaction between the work-off and the work-off, and it is difficult to generate the measurement error due to the effect of yawing. However, this invention is not limited to this, You may use a reflecting surface other than a prism.

As the reference mirrors 14y ₁ and 14y ₂ , planar mirrors may be used, as well as prisms other than the hollow retro reflector, and non-hollow retro reflectors (also called corner cube prisms). The position measuring device in the non-scanning direction of the reticle stage RST is not limited to a laser interferometer, and an encoder or other position measuring device may be used.

When the laser interferometer is used as the position measuring device in the non-scanning direction of the reticle stage RST, the above-described reticle X interferometer is in addition to the positional information in the non-scanning direction (X-axis direction) in at least one of the θy direction and the θz direction. It is good also as a multi-axis interferometer which has a some longitudinal axis so that rotation amount can be measured.

In the above embodiment, the above-described error measurement is described using a reticle reference plate (RFM) having a measurement mark, but the present invention is not limited thereto, and the measurement mark is formed on a dedicated measurement reticle or a reticle for manufacturing a device. You may use a thing. In any case, it is preferable to measure the manufacturing error of the measurement mark in advance, and correct this measurement error at the time of measuring the position of the reticle stage, at the time of position control, or at the time of preparing the correlation information described above. In addition, the measurement mark formed in a reticle reference plate (RFM) or a measurement reticle is not limited to a cross mark, The shape etc. may be arbitrary.

In the above embodiment, the reticle alignment system of the imaging method is used to obtain the above-described correlation information. However, the reticle alignment system is not limited to the imaging system, but scattered light or diffraction generated from the above-described measurement mark or reference mark. A method of detecting light or the like may be used, and the reticle alignment system may use another optical sensor or the like. For example, a coherent beam is irradiated to one of the measurement marks disposed on the object plane side of the projection optical system and the reference mark disposed on the image plane side, and the diffracted light generated at the one mark through the projection optical system is the other. May be irradiated to the mark and the diffraction light of the same order generated by the other mark is interfered with and detected.

Moreover, in the said embodiment, although the case where a single-pass heterodyne interferometer was used as reticle Y interferometers 13y ₁ and 13y ₂ was demonstrated, it cannot be overemphasized that this invention is not limited to this. That is, as the reticle Y interferometers 13y ₁ and 13y ₂ , a so-called double pass laser interferometer may be used, and in this case, the main controller 20 also corrects the reticle stage (RST) with high precision according to the procedure described above. Position measurement and position control can be performed. In addition, the present invention can be suitably applied even when a heterodyne interferometer, as well as other laser interferometers, as well as other optical interference measuring instruments are used.

In the above embodiment, the pair of Y-axis moving mirrors 15y ₁ and 15y ₂ is fixed to the upper surface of the reticle stage RST. However, the arrangement is not limited thereto, and for example, the reticle stage ( It may be fixed to the side surface of RST, or may be an integral structure which processes the edge part of a reticle stage (RST; reticle fine motion stage), and makes it a moving mirror. In addition, since it is preferable that the side axis (measurement beam) of the reticle Y interferometer substantially coincides with the pattern surface of the reticle R with respect to the optical axis direction (Z-axis direction) of the projection optical system PL, the Y-axis moving mirror is If the measurement beam can be reflected in the state, the arrangement may be arbitrary. The number of the Y-axis moving mirrors 15y ₁ and 15y ₂ may be one or three or more. Incidentally, in the above embodiment, the reference mirrors 14x, 14y ₁ , 14y ₂ of the reticle interferometer 13 are fixed to the barrel of the projection optical system PL, but the present invention is not limited thereto, and the arrangement may be arbitrary. Moreover, in the said embodiment, although the moving mirror is formed in the reticle fine motion stage, in addition to this, a Y-axis interferometer may also be arrange | positioned at the reticle coarse motion stage, and a moving mirror (retro reflector) may be formed in the end part correspondingly, In this case, the present invention can also be applied. The reticle stage RST is not limited to the seasoning stage and the configuration may be arbitrary.

In the above embodiment, the present invention has been described in the case where the present invention is applied to a step-and-scan projection exposure apparatus, but the present invention is not limited thereto, and the exposure apparatus includes at least one stage apparatus having a relatively large moving stroke in one axis direction. The present invention can be preferably applied. For example, in the case of an equal magnification scanning exposure apparatus (used as a liquid crystal exposure apparatus) and the like that the mask stage and the substrate stage move in the same direction with respect to the projection optical system, for example, instead of the mask stage or the mask stage. In addition, it is possible to apply the position measuring method and the position control method of this invention also to a board | substrate stage. In addition, the position measuring method and the position control method of the present invention are not limited to the stage of the exposure apparatus, and if the reflecting surface is formed and has a predetermined stroke in at least one axis direction and is movable in the direction orthogonal to the one axis, It is possible to apply preferably.

Moreover, in the said embodiment, although the case where this invention was applied to the exposure apparatus for semiconductor manufacture was demonstrated, it is not limited to this, For example, the liquid crystal exposure apparatus which transfers a liquid crystal display element pattern on a square glass plate, and a plasma display. Display apparatuses such as organic ELs, exposure apparatuses for transferring device patterns used for manufacturing thin film magnetic heads onto ceramic wafers, and exposure apparatuses used for manufacturing imaging devices (such as CCDs), micromachines, DNA chips, and the like. Applicable In addition to microdevices such as semiconductor devices, exposure apparatuses for transferring circuit patterns to glass substrates or silicon wafers for manufacturing reticles or masks used in optical exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, and electron beam exposure apparatuses, etc. The present invention can be applied. Here, in the exposure apparatus using DUV (ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used, and as a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, magnesium fluoride, or quartz is used. Etc. are used. In addition, a transmissive mask (stencil mask, membrane mask) is used in a proximity X-ray exposure apparatus, an electron beam exposure apparatus, etc., and a silicon wafer etc. are used as a mask substrate.

Further, in the embodiment, the character, such as KrF excimer laser light source as a light source external light source, F ₂ laser, ArF but by using the pulse laser light source of vacuum ultraviolet region such as an excimer laser is not limited to this Ar ₂ laser light source (output You may use another vacuum ultraviolet light source, such as wavelength 126nm). For example, not only the laser light output from each said light source as vacuum ultraviolet light, but also the infrared wavelength or the visible wavelength single wavelength laser light oscillated by a DFB semiconductor laser or a fiber laser, for example, Erbium (Er) Or harmonics which are amplified by a fiber amplifier doped with erbium and ytterbium (Yb) and wavelength-converted into ultraviolet light using a nonlinear optical crystal. The present invention can also be applied to an exposure apparatus using, for example, EUV light or X-rays, or charged particle beams such as electron beams or ion beams. In addition, the present invention may also be applied to a liquid immersion exposure apparatus or the like in which a liquid is filled between the projection optical system PL and the wafer disclosed in, for example, International Publication No. WO99 / 49504. Moreover, you may apply this invention to the exposure apparatus which has two wafer stages which are each independently movable. This twin wafer stage type exposure apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. H10-214783 and corresponding US Patent No. 6,341,007, or WO 98/40791, and corresponding US Patent No. 6,262,796. The disclosures in the above publications and US patents are incorporated by reference herein as long as the national legislation of the designated or selected countries designated in this International Application allows.

In the above embodiment, the case where a reduction system and a refractometer are used as the projection optical system is described, but the present invention is not limited thereto, and an equal magnification or a magnification system may be used as the projection optical system. You may use it. In the case of using the same reduction system as in the above embodiment, the projection magnification β may be 1/5, 1/6, etc. In this case, the size, arrangement, etc. of the measurement mark, the reference mark, etc. are determined according to the projection magnification. It is preferable.

In addition, an optical optical system and a projection optical system PL constituted by a plurality of lenses are mounted on the exposure apparatus main body for optical adjustment, and at the same time, a reticle stage RST or wafer stage WST composed of a plurality of mechanical parts is attached to the exposure apparatus main body. The exposure apparatus 100 of this embodiment can be manufactured by connecting wiring and piping, and carrying out total adjustment (electrical adjustment, operation confirmation, etc.) again. In addition, it is preferable to manufacture an exposure apparatus in the clean room where temperature, a clean degree, etc. were managed.

<< device manufacturing method >>

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus in a lithography step will be described.

Fig. 7 shows a flowchart of an example of manufacturing a device (semiconductor chip such as IC or LSI, liquid crystal panel, CCD, thin film magnetic head, micromachine, etc.). As shown in FIG. 7, first, in step 201 (design stage), the function and performance design of the device (for example, circuit design of a semiconductor device, etc.) are performed, and pattern design for realizing the function is performed. Subsequently, in step 202 (mask fabrication step), a mask on which the designed circuit pattern is formed is prepared. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step 204 (wafer processing step), using the mask and the wafer prepared in steps 201 to 203, an actual circuit or the like is formed on the wafer by lithography or the like as described later. Next, in step 205 (device assembly step), the device is assembled using the wafer processed in step 204. This step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.

Finally, in step 206 (inspection step), the operation check test, the endurance test and the like of the device created in step 205 are inspected. After this process, the device is completed and shipped.

8 shows a detailed flow example of the above step 204 in the semiconductor device. In Fig. 8, the surface of the wafer is oxidized in step 211 (oxidation step). In step 212 (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step 214 (ion implantation step), ions are implanted into the wafer. Each of the above steps 211 to 214 constitutes a pretreatment step for each step of wafer processing, and is selected and executed according to the processing required in each step.

In each step of the wafer process, when the above-described pretreatment step is completed, the post-treatment step is executed as follows. In this post-treatment step, a photosensitive agent is first applied to the wafer in step 215 (resist formation step). Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred to the wafer by the exposure apparatus and the exposure method described above. Next, in step 217 (development step), the exposed wafer is developed, and in step 218 (etching step), the exposed members of portions other than the portion where the resist remains are removed by etching. In step 219 (resist removal step), the unnecessary resist is removed after the etching is completed.

By repeating these pretreatment steps and post-treatment steps, a circuit pattern is formed on the wafer multiplely.

When the device manufacturing method of the present embodiment described above is used, the exposure apparatus of the embodiment and the exposure method thereof are used in the exposure step (step 216), so that the pattern of the reticle can be accurately transferred onto the wafer. As a result, it becomes possible to improve the productivity (including yield) of the high integration microdevice.

Industrial availability

As described above, the position measuring method of the present invention is suitable for measuring the position information of the movable body on which the reflecting surface is formed by using an optical interference measuring instrument. Moreover, the position control method of this invention is suitable for controlling the position of the mobile body in which the positional information of 1-axis direction is measured using a wave interference measuring instrument. In addition, the exposure method and exposure apparatus of the present invention are suitable for transferring a pattern of a micro device onto a photosensitive object. Moreover, the device manufacturing method of this invention is suitable for production of a micro device.

Claims (32)

A position measuring method for measuring position information in at least one axis direction of a moving object having a reflecting surface by using an optical interference measuring instrument. A position perpendicular to the first axis while measuring position information of the moving object in a first axial direction based on an output of the wave interference measuring instrument that irradiates a reflecting beam to the reflecting surface and receives the reflected light beam; Measuring position information of the movable body in the biaxial direction using a second axial position measuring device; And A position measurement error of a reference point on the reflective surface at least due to a positional relationship between an optical axis of a measuring beam of the optical interference measuring instrument and an optical axis of a reference beam, and the position of the movable body with respect to the second axis direction corresponding thereto; Measurement error of the positional information of the movable body with respect to the first axial direction by the wave interference measuring instrument based on the correlation information indicating the relation of the position and the positional information of the movable body with respect to the measured second axis direction. Position measuring method comprising a. The method of claim 1, Prior to the measuring step, the second beam is detected while detecting the position in the first axial direction of the moving body based on an output of the wave interference measuring instrument that irradiates a measuring beam to the reflective surface and receives the reflected light beam. A position measuring error of each of the reference points on the reflective surface at the plurality of positions in the second axial direction is obtained by using the axial position measuring device to move the movable body in the second axial direction. And measuring the correlation information based on the error. The method of claim 2, The position measurement error of the reference point on the reflective surface is calculated by a predetermined calculation based on the deviation amount with respect to the reference optical axis of the measurement optical axis of the optical interference interference measuring instrument and the position information in the second axis direction of the movable body. Position measurement method. The method of claim 2, The position measurement error of the reference point on the reflective surface is calculated based on the measurement result of measuring the positional relationship between the measurement mark formed on a part of the moving object and the reference mark formed on the reference object. The method of claim 2, Wherein said correlation information is data of a function calculated on the basis of data of each plot point plotted on a predetermined coordinate system a position measurement error of a reference point on said reflection surface obtained for each position in said second axis direction. Measurement method. The method of claim 2, And the correlation information is table data created by using a position measurement error of a reference point on the reflective surface obtained for each position in the second axis direction. The method of claim 2, In the step of calculating the measurement error, the position measurement error for each position in the second axis direction in the correlation information is interpolated by a predetermined interpolation operation according to the measured position information of the movable body in the second axis direction. And calculating the error using a result of the calculation. The method of claim 2, In the step of preparing the correlation information, the movable body is moved in the second axial direction while substantially maintaining the position in the first axial direction of the movable body at a predetermined coordinate position based on the output of the wave interference measuring instrument. Position measuring method characterized in that. The method of claim 1, In the step of calculating the measurement error, the measurement error is calculated by further considering the posture of the moving object. The method of claim 1, And the position measurement error included in the correlation information is further derived from wavefront aberration generated in the measurement beam. The method of claim 1, And the reflecting surface is a reflecting surface of a hollow retro reflector fixed to the movable body. The method of claim 1, Calculating position information of the movable body in the first axial direction in which the measurement error is corrected. A position control method for controlling the position of a moving object in which at least one axial position information is measured using an optical interference measuring instrument, A position measuring step of measuring position information in the first axial direction of the movable body by executing the position measuring method according to any one of claims 1 to 12; And And controlling at least the position in the first axial direction of the movable body in consideration of the information obtained in the position measuring step. An exposure method for transferring a pattern formed on the mask on the photosensitive object by synchronously moving a mask and the photosensitive object in a predetermined direction, The positional information of the said predetermined direction of at least one of the 1st movable body on which the said mask is mounted, and the 2nd movable body on which the said photosensitive object is mounted, is measured using the position measuring method in any one of Claims 1-12. And taking into account the information obtained as a result of the measurement, controlling the position of at least one of the first movable body and the second movable body in the predetermined direction to transfer the pattern onto the photosensitive object. A device manufacturing method comprising a lithography process, In the lithography step, the pattern of the micro device is transferred onto the photosensitive object using the exposure method according to claim 14. An exposure apparatus for synchronously moving a mask and a photosensitive object in a predetermined scanning direction to transfer a pattern formed on the mask onto the photosensitive object, A first stage on which the mask is mounted and a reflective surface is formed; A second stage on which the photosensitive object is mounted; A drive system driving the first stage and the second stage; An optical interference measuring instrument for irradiating a measurement beam to the reflecting surface to measure position information of the first stage with respect to the scanning direction, and position information for the non-scanning direction orthogonal to the scanning direction of the first stage; A first measuring system having a measuring device for measuring; A second measurement system for measuring positional information relating to at least the scanning direction of the second stage; And Position measurement error of the reference point on the reflecting surface and at least corresponding to the measurement result of the first and second measurement systems and the positional relationship between the optical axis of the measuring beam of the wave interference measuring instrument and the optical axis of the reference beam. And a control device for controlling the drive system based on correlation information indicating a positional relationship of the first stage with respect to the non-scanning direction. The method of claim 16, The control device uses the correlation information and positional information about the non-scanning direction of the first stage, and the mask and the photosensitive object due to the measurement error of the first stage by the optical interference measuring instrument. And a position error correcting relative position error with respect to the scanning direction. The method of claim 16, The control device calculates information on the measurement error of the first stage by the optical interference measuring instrument based on the correlation information and the positional information about the non-scanning direction of the first stage, And the calculated information is used when one stage moves in the scanning direction. The method of claim 16, The control device is configured to position the scan direction of the first stage in which the measurement error is corrected by the wave interference measuring instrument based on the correlation information and the position information on the non-scan direction of the first stage. And calculate the information, and use the calculated information when the first stage moves in the scanning direction. The method of claim 16, The correlation information moves the first stage in the non-scanning direction through the drive system while the control device detects the position of the scanning direction of the first stage based on the output of the wave interference measuring instrument. And a pre-created exposure apparatus based on a position measurement error of a reference point on the reflective surface respectively obtained at a plurality of positions in the non-scanning direction. The method of claim 20, And the control device includes a storage device which controls the movement of the first stage through the drive system when the correlation information is created and stores the generated correlation information. The method of claim 20, And a mark measuring instrument for measuring a positional relationship between the measurement mark formed on a part of the first stage and the reference mark formed on the reference object, The position measurement error of the reference point on the reflective surface is obtained based on the measurement result of the mark measurement system. The method of claim 20, And the correlation information is table data created by using a position measurement error of a reference point on the reflective surface obtained for each position in the non-scanning direction. The method of claim 23, The control device interpolates the position measurement error for each position of the non-scan direction in the correlation information by a predetermined interpolation operation according to the measured position information on the non-scan direction of the first stage. Exposure apparatus, characterized in that for calculating the measurement error of the optical interference measuring instrument. The method of claim 20, And the correlation information is data of a function calculated based on data of each plot point plotted on a predetermined coordinate system on the position measurement error of a reference point on the reflective surface obtained for each position in the non-scanning direction. . The method of claim 20, When the correlation information is generated, the control device moves the first stage in the non-scanning direction while substantially maintaining the first stage at a predetermined position with respect to the scanning direction based on the output of the optical interference measuring instrument. Exposure apparatus. The method of claim 16, And the control device calculates the position measurement error further considering the attitude of the first stage. The method of claim 16, And the position measurement error included in the correlation information is further derived from wavefront aberration generated in the measurement beam. The method of claim 16, And the reflecting surface is a reflecting surface of the hollow retro reflector. An exposure apparatus for transferring a pattern of the first object on the second object by synchronously moving a first object and a second object, A stage system having a first movable body for holding the first object, a second movable body for holding the second object, and a drive system for independently driving the first and second movable bodies, respectively; A first interferometer system for irradiating a measuring beam to a retro reflector provided in the first movable body to measure positional information of the first movable body regarding a scanning direction in which the first object is synchronously moved; A second interferometer system for measuring positional information of the second movable body; And And a control device for controlling the drive system based on measurement results of the first and second interferometer systems and error information on position measurement of the first movable body due to the retro reflector. The method of claim 30, And the control device controls the drive system using different error information according to the position of the first movable body in the non-scanning direction orthogonal to the scanning direction. A device manufacturing method comprising a lithography process, In the lithography process, exposure is performed using the exposure apparatus in any one of Claims 16-31.