WO2014006935A1

WO2014006935A1 - Position measurement device, stage apparatus, exposure equipment, and device manufacturing method

Info

Publication number: WO2014006935A1
Application number: PCT/JP2013/056243
Authority: WO
Inventors: 要助栗山; 博人今川
Original assignee: 株式会社ニコン
Priority date: 2012-07-06
Filing date: 2013-03-07
Publication date: 2014-01-09

Abstract

To simultaneously and stably perform position measurement in the in-plane direction of a substrate and position measurement in the normal direction of the substrate, a position measurement device is provided with: a polarized beam splitter which is fixedly attached to a first member; a reflective diffraction grating which is attached to a second member and has a periodic structure along a first direction; a first measurement unit which measures the relative position of the second member along the first direction on the basis of the interference between first measurement light that is diffracted light along the first direction generated from the diffraction grating in response to first polarized light incident on the diffraction grating via a first path in the polarized beam splitter, and second polarized first reference light corresponding to the first measurement light; and a second measurement unit which measures the relative position of the second member along a second direction on the basis of the interference between second measurement light that is zero-order light generated along the second direction from the diffraction grating in response to light incident on the diffraction grating via a second path in the polarized beam splitter, and second reference light corresponding to the second measurement light.

Description

Position measuring apparatus, stage apparatus, exposure apparatus, and device manufacturing method

The present invention relates to a position measuring apparatus, a stage apparatus, an exposure apparatus, and a device manufacturing method.

Conventionally, in an exposure apparatus used in a photolithography process for producing electronic devices (microdevices) such as semiconductor elements, a laser interferometer is used to measure the position of a substrate stage that holds and moves an exposure target substrate. Is going. However, in the laser interferometer, since the optical path of the measurement beam is long and the optical path length changes, short-term fluctuations in the measured value due to the temperature fluctuation of the atmosphere on the optical path cannot be ignored.

Therefore, for example, a measurement obtained by irradiating measurement light such as laser light onto a diffraction grating attached to a substrate stage, and photoelectrically converting interference light between the diffraction light generated from the diffraction grating and the corresponding reference light A position measuring device that measures a relative movement amount of a substrate stage from a signal has been proposed (see, for example, Patent Document 1). In this position measurement apparatus, position measurement can be performed more stably than a laser interferometer.

U.S. Pat. No. 8,134,688

However, when a conventional position measurement apparatus is applied to the position measurement of the substrate stage of the exposure apparatus, the position measurement in the in-plane direction of the substrate and the position measurement in the normal direction of the substrate are performed independently. The stability of is not always sufficient.

The present invention has been made in view of the above-described problems. For example, when applied to the position measurement of the substrate stage of an exposure apparatus, the position measurement in the in-plane direction of the substrate and the position measurement in the normal direction of the substrate are performed. It is an object of the present invention to provide a position measuring apparatus capable of simultaneously and stably performing the above. The present invention also provides an exposure that can position the photosensitive substrate on the substrate stage with high accuracy with respect to the projection optical system using, for example, a position measuring device that simultaneously and stably measures the position of the substrate stage. An object is to provide an apparatus.

In order to solve the above-described problem, in the first embodiment, in the position measurement device that measures the relative position of the second member, the relative position of which is variable with respect to the first member,
A polarizing beam splitter fixedly attached to the first member;
A reflective diffraction grating attached to the second member and having a periodic structure along a first direction;
A first measurement light which is a diffracted light along the first direction generated from the diffraction grating in response to the first polarized light incident on the diffraction grating via a first path in the polarization beam splitter; A first measurement unit that measures a relative position of the second member along the first direction based on interference with the second polarized first reference light corresponding to one measurement light;
A second measurement light that is zero-order light generated along the second direction from the diffraction grating in response to the light incident on the diffraction grating via the second path in the polarization beam splitter; and the second measurement light There is provided a position measuring device comprising: a second measuring unit that measures a relative position of the second member along the second direction based on interference with a corresponding second reference light. .

In the second embodiment, in the position measurement device that measures the relative position of the second member provided with a reflection type diffraction grating having a periodic structure along the first direction, the relative position with respect to the first member being variable.
A polarizing beam splitter fixedly attached to the first member;
Generated from the diffraction grating along the predetermined path in the first plane in response to light obliquely incident on the diffraction grating along a predetermined path in the first plane including the first direction via the polarizing beam splitter First relative position of the second member along the first direction is measured based on interference light between the first measurement light that is diffracted light and the first reference light corresponding to the first measurement light. With a measuring unit,
The first measurement unit deflects light that has passed through the polarization beam splitter, and obliquely enters the first region on the diffraction grating along the first path at a Littrow angle of the reflective diffraction grating. Provided is a position measuring device having a member.

In the third embodiment, in a stage apparatus including a stage that holds an object and a drive unit that moves the stage,
Comprising the position measuring device of the first form or the second form,
One of the polarization beam splitter and the diffraction grating is attached to the stage.

In the fourth embodiment, in an exposure apparatus that exposes a predetermined pattern on a substrate,
An exposure apparatus is provided, comprising a stage device of a third form that holds and moves the substrate.

In the fifth embodiment, using the exposure apparatus of the fourth embodiment, exposing the predetermined pattern to the substrate;
Developing the substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the substrate;
And processing the surface of the substrate through the mask layer. A device manufacturing method is provided.

In the position measuring apparatus of the present invention, for example, when applied to the position measurement of the substrate stage of the exposure apparatus, the position measurement in the in-plane direction of the substrate and the position measurement in the normal direction of the substrate are performed simultaneously and stably. be able to. In the exposure apparatus of the present invention, for example, a position measurement device that simultaneously and stably measures the position of the substrate stage is used to accurately align the photosensitive substrate on the substrate stage with respect to the projection optical system. Can do.

It is a figure which shows schematically the structure of the exposure apparatus provided with the position measuring device concerning 1st Embodiment. It is a figure which shows roughly the arrangement | positioning of the diffraction grating and measurement unit which comprise the position measuring device of 1st Embodiment. It is a figure explaining the measurement principle of the X direction position of the diffraction grating attached to the wafer stage, and the Y direction position. It is a figure explaining the measurement principle of the Z direction position of the diffraction grating attached to the wafer stage. It is a figure showing roughly the composition of the position measuring device concerning a 1st embodiment. It is a figure which shows the incident position of the some measurement light with respect to the optical surface by the side of the input / output unit of a polarization beam splitter. It is a figure which shows the position of the measurement point in the entrance plane by the side of the polarizing beam splitter of a diffraction grating. It is a figure which shows the structure of the incident surface by the side of the polarization beam splitter of a reference member, and the incident position of the some measurement light in this incident surface. It is a figure which shows the structure of the optical surface by the side of the diffraction grating of a polarizing beam splitter. It is a figure which shows the structure of the optical surface by the side of the reference member of a polarization beam splitter. It is a figure which shows roughly arrangement | positioning of the diffraction grating and measurement unit in the modification applied to the position measurement of a mask stage. It is a figure which shows schematically the structure of the exposure apparatus provided with the position measuring device concerning 2nd Embodiment. It is a figure which shows roughly the arrangement | positioning of the diffraction grating and measurement unit which comprise the position measuring device of 2nd Embodiment. It is a figure explaining the measurement principle of the X direction position of the diffraction grating attached to the wafer stage, and the Y direction position. It is a figure explaining the measurement principle of the Z direction position of the diffraction grating attached to the wafer stage. It is a figure which shows schematically the structure of the position measuring device concerning 2nd Embodiment. It is a figure which shows the position of the measurement point in the entrance plane of the diffraction grating of 2nd Embodiment, and the position of the incident light in relation to each measurement point. It is a figure which shows the position of the measurement point concerning a modification, and the position of the incident light in relation to each measurement point. It is a figure which shows schematically the structure of the deflection | deviation member concerning a modification. It is a figure which shows roughly arrangement | positioning of the diffraction grating and measurement unit in the modification applied to the position measurement of a mask stage. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of liquid crystal devices, such as a liquid crystal display element.

Hereinafter, embodiments will be described with reference to the accompanying drawings. FIG. 1 is a view schematically showing a configuration of an exposure apparatus provided with a position measuring apparatus according to the first embodiment. In the first embodiment, the position measurement apparatus of this embodiment is applied to the position measurement of the substrate stage that moves while holding the photosensitive substrate in the exposure apparatus. In FIG. 1, the Z axis is set in the normal direction of the image plane of the projection optical system PL (that is, the direction of the optical axis AX of the projection optical system PL: the vertical direction on the paper surface of FIG. 1) in the image plane of the projection optical system PL. The X axis is set parallel to the paper surface of FIG. 1, and the Y axis is set perpendicular to the paper surface of FIG. 1 in the image plane of the projection optical system PL.

Referring to FIG. 1, exposure light (illumination light) is supplied from a light source LS to the exposure apparatus of the first embodiment. As the exposure light source LS, for example, an ArF excimer laser light source that supplies light with a wavelength of 193 nm, a KrF excimer laser light source that supplies light with a wavelength of 248 nm, or the like can be used. The exposure apparatus of the first embodiment includes an illumination optical system IL that illuminates a mask (reticle) M on which a pattern to be transferred is formed by illumination light (exposure light) emitted from a light source LS.

The illumination optical system IL is composed of an optical integrator (homogenizer), a field stop, a condenser lens, and the like. The illumination optical system IL illuminates, for example, the entire rectangular pattern region of the mask M, or an elongated slit-shaped region (for example, a rectangular region) along the X direction in the entire pattern region.

The light from the pattern of the mask M forms a pattern image of the mask M in the unit exposure region of the wafer (photosensitive substrate) W coated with the photoresist via the projection optical system PL. That is, in the unit exposure area of the wafer W, a rectangular area similar to the entire pattern area of the mask M or a rectangular area elongated in the X direction (optically corresponding to the illumination area on the mask M) A mask pattern image is formed in the (static exposure region).

The mask M is held substantially parallel to the XY plane on the mask stage MS. The mask stage MS incorporates a mechanism for moving the mask M in the X direction, the Y direction, the rotation direction around the Z axis, and the like. The mask stage MS is provided with a movable mirror (not shown), and a mask laser interferometer (not shown) using this movable mirror moves the position of the mask stage MS (and hence the mask M) in the X direction, the Y direction, and the rotation. Measure the position of the direction in real time.

The wafer W is held substantially parallel to the XY plane on a wafer stage (substrate stage) WS via a wafer holder (not shown). That is, on the wafer stage WS that holds the wafer W and moves on the exposure apparatus surface plate, the wafer W is held at a predetermined position in a predetermined posture. The wafer stage WS has a mechanism for moving the wafer stage WS (and thus the wafer W) in the X direction, the Y direction, the Z direction, the rotation direction around the X axis, the rotation direction around the Y axis, and the rotation direction around the Z axis. It has been incorporated.

In the exposure apparatus of the first embodiment, the position in the X direction, the position in the Y direction, the position in the Z direction, the position in the rotation direction around the X axis, and the position in the rotation direction around the Y axis of the wafer stage WS (and thus the wafer W). And a position measuring device 1 that measures the position in the rotation direction around the Z axis in real time. As shown in FIGS. 1 and 2, the position measuring apparatus 1 includes a pair of reflective diffraction gratings 10 that are spaced apart in the X direction with the wafer W interposed therebetween, and the projection optical system PL in the X direction. And four measuring units 11 installed side by side. FIG. 2 shows a reference state in which the center Wa of the wafer W and the optical axis AX of the projection optical system PL are at the same position on the XY plane.

The diffraction grating 10 has, for example, an elongated rectangular outer shape along the Y direction, and is fixedly (or detachably) attached to the wafer stage WS. The four measurement units 11 are fixedly attached to the exposure apparatus main body isolated from the wafer stage WS. Of the four measurement units 11, the first pair of measurement units 11 are arranged side by side in the X direction on the + X direction side of the projection optical system PL, and the second pair of measurement units 11 is -X of the projection optical system PL. They are arranged side by side in the X direction on the direction side.

Hereinafter, in order to simplify the description, it is assumed that the pair of diffraction gratings 10 are arranged symmetrically with respect to an axis extending in the Y direction through the center Wa of the wafer W and have the same configuration. Further, the four measurement units 11 are arranged symmetrically with respect to the axis extending in the Y direction through the optical axis AX so as to be along the axis extending in the X direction through the optical axis AX of the projection optical system PL, and have the same configuration. It shall have. Further, it is assumed that the wafer stage WS moves with respect to the stationary exposure apparatus main body. The specific configuration and operation of the position measuring device 1 will be described later.

The output of the mask laser interferometer and the output of the position measuring device 1 are supplied to the control system CR. The control system CR controls the position of the mask M in the X direction, the Y direction, and the rotation direction based on the measurement result of the mask laser interferometer. That is, the control system CR transmits a control signal to a mechanism incorporated in the mask stage MS, and this mechanism moves the mask stage MS based on the control signal, whereby the position of the mask M in the X direction, the Y direction. And adjust the position in the rotation direction.

Based on the measurement result of the position measuring device 1, the control system CR makes the focus position (Z-direction position) and tilt angle (X-axis) of the wafer W match the surface of the wafer W with the image plane of the projection optical system PL. The rotation angle around and the rotation angle around the Y axis are controlled. That is, the control system CR transmits a control signal to the wafer stage drive system DRw, and the wafer stage drive system DRw drives the wafer stage WS based on the control signal, thereby adjusting the focus position and tilt angle of the wafer W. Do.

Further, the control system CR controls the position of the wafer W in the X direction, the Y direction, and the rotational direction around the Z axis based on the measurement result of the position measuring device 1. That is, the control system CR transmits a control signal to the wafer stage drive system DRw, and the wafer stage drive system DRw drives the wafer stage WS based on the control signal, whereby the position of the wafer W in the X direction, Adjust the position and the position in the rotation direction around the Z axis.

In the step-and-repeat method, the pattern image of the mask M is collectively exposed to one unit exposure area among a plurality of unit exposure areas set vertically and horizontally on the wafer W. Thereafter, the control system CR sends a control signal to the wafer stage drive system DRw, and projects another unit exposure region of the wafer W by moving the wafer stage WS along the XY plane by the wafer stage drive system DRw. Positioning is performed with respect to the optical system PL. Thus, the operation of collectively exposing the pattern image of the mask M to the unit exposure area of the wafer W is repeated.

In the step-and-scan method, the control system CR transmits a control signal to a mechanism incorporated in the mask stage MS, and also transmits a control signal to the wafer stage drive system DRw, according to the projection magnification of the projection optical system PL. The pattern image of the mask M is scanned and exposed to one unit exposure region of the wafer W while the mask stage MS and the wafer stage WS are moved in the Y direction at the speed ratio. Thereafter, the control system CR sends a control signal to the wafer stage drive system DRw, and projects another unit exposure region of the wafer W by moving the wafer stage WS along the XY plane by the wafer stage drive system DRw. Positioning is performed with respect to the optical system PL. Thus, the operation of scanning and exposing the pattern image of the mask M to the unit exposure area of the wafer W is repeated.

That is, in the step-and-scan method, the position of the mask M and the wafer W is controlled using the position measuring device 1, the wafer stage driving system DRw, etc., and the rectangular (generally slit-shaped) static exposure region is shortened. By moving (scanning) the mask stage MS and the wafer stage WS along the Y direction, which is the side direction, and the mask M and the wafer W synchronously (scanning), the long side of the static exposure region is formed on the wafer W. The mask pattern is scanned and exposed to an area having a width equal to the length of the wafer W and a length corresponding to the scanning amount (movement amount) of the wafer W.

Hereinafter, prior to the description of the specific configuration and operation of the position measuring device 1, the measurement principle of the position measuring device 1 will be described. FIG. 3 is a diagram for explaining the measurement principle of the X-direction position and the Y-direction position of the diffraction grating attached to the wafer stage. Referring to FIG. 3, measurement light 31 including a p-polarized component and an s-polarized component enters the same optical path along the X direction on a polarizing beam splitter PBS fixedly attached to the exposure apparatus main body. Of the measurement light 31 incident on the polarization beam splitter PBS, the s-polarized light reflected in the Z direction on the polarization separation surface is emitted from the polarization beam splitter PBS and is reflected on the reflective diffraction grating 10 attached to the wafer stage WS. Is incident on the measurement point 32a.

The diffraction grating 10 has a form of a plane parallel plate having an incident surface substantially parallel to the XY plane with respect to the polarization beam splitter PBS. The diffraction grating 10 is provided with a diffraction pattern having a two-dimensional periodic structure along the X direction and the Y direction. According to the s-polarized light incident on the measurement point 32a on the diffraction grating 10, + 1st order diffracted light 31sa and −1st order diffracted light 31sb are generated along the X direction (along the XZ plane) from the diffraction grating 10, and A + 1st order diffracted light 31sc (not shown) and a −1st order diffracted light 31sd (not shown) are generated from the diffraction grating 10 along the Y direction (along the YZ plane).

The + 1st order diffracted light 31sa and the −1st order diffracted light 31sb, which are s-polarized measurement light generated from the diffraction grating 10 along the X direction, are deflected in the Z direction by the deflecting

members

33a and 33b, respectively, and then the polarization beam splitter PBS. It propagates inside and is reflected in the X direction by the polarization separation plane. The deflecting

members

33a and 33b are fixedly attached to the polarization beam splitter PBS and have a one-dimensional periodic structure diffraction pattern along the X direction. The diffraction patterns of the deflecting

members

33a and 33b may be formed on the optical surface facing the diffraction grating 10 of the polarization beam splitter PBS.

Of the measurement light 31 incident on the polarization beam splitter PBS, the p-polarized light transmitted through the polarization separation surface is emitted from the polarization beam splitter PBS and fixedly attached to the exposure apparatus main body (that is, integrated with the polarization beam splitter PBS). Incident on a point 34a on the reference member RM). The reference member RM has the form of a plane parallel plate with the incident surface along the YZ plane facing the polarization beam splitter PBS. In the region including the point 34a on the reference member RM, a diffraction pattern having a two-dimensional periodic structure along the X direction and the Y direction is provided. In accordance with the p-polarized light incident on the point 34a on the reference member RM, + 1st order diffracted light 31pa and −1st order diffracted light 31pb are generated along the Z direction (along the XZ plane) from the reference member RM. A + 1st order diffracted light 31pc (not shown) and a −1st order diffracted light 31pd (not shown) are generated along the Y direction (along the XY plane) from the member RM.

The + 1st order diffracted light 31pa and the −1st order diffracted light 31pb, which are p-polarized reference light generated along the Z direction from the reference member RM, are deflected in the X direction by the deflecting

members

35a and 35b, respectively, and then the polarization beam splitter PBS Propagates inside and transmits through the polarization splitting surfaces. The deflecting

members

35a and 35b are fixedly attached to the polarization beam splitter PBS, and have a one-dimensional periodic structure diffraction pattern along the Z direction. The diffraction patterns of the deflecting

members

35a and 35b may be formed on the optical surface facing the reference member RM of the polarization beam splitter PBS.

The s-polarized + 1st order diffracted light 31sa reflected in the X direction on the polarization separation surface of the polarization beam splitter PBS and the p-polarized + 1st order diffracted light 31pa transmitted through the polarization separation surface are along the same path. And enters a folding member 36a such as a corner cube fixedly attached to the polarization beam splitter PBS. The s-polarized + 1st-order diffracted light 31sa and the p-polarized + 1st-order diffracted light 31pa that have been translated in the Z direction by the action of the folding member 36a and returned to the polarization beam splitter PBS are incident on the polarization separation surface of the polarization beam splitter PBS.

The + 1st-order diffracted light 31sa, which is s-polarized measurement light reflected in the Z direction on the polarization separation surface of the polarization beam splitter PBS, is emitted from the polarization beam splitter PBS and moved from the measurement point 32a on the diffraction grating 10 to the −X direction side. The incident light is incident on the point 32b that is spaced apart. In response to the s-polarized + 1st order diffracted light 31sa incident on the point 32b on the diffraction grating 10, the + 1st order diffracted light 31saa is generated along the X direction from the diffraction grating 10. The + 1st-order diffracted light 31saa, which is s-polarized measurement light generated along the X direction from the diffraction grating 10, is deflected in the Z direction by a deflecting member 33c configured in the same manner as the deflecting

members

33a and 33b, and then polarized beam splitter. It propagates inside the PBS and is reflected in the X direction by the polarization separation surface.

The + first-order diffracted light 31pa, which is p-polarized reference light that has passed through the polarization separation surface of the polarization beam splitter PBS, is emitted from the polarization beam splitter PBS, and is spaced from the point 34a on the reference member RM to the −Z direction side by the point 34b. Is incident on. In a region including the point 34b on the reference member RM, a diffraction pattern having a one-dimensional periodic structure along the Z direction is provided. In response to the p-polarized + 1st order diffracted light 31pa incident on the point 34b on the reference member RM, the + 1st order diffracted light 31paa is generated along the Z direction from the reference member RM.

The + 1st-order diffracted light 31paa, which is p-polarized reference light generated along the Z direction from the reference member RM, is deflected in the X direction by a deflecting member 35c configured in the same manner as the deflecting

members

35a and 35b, and then the polarization beam splitter. Propagates through the PBS and passes through the polarization separation surface. The + 1st order diffracted light 31saa that is the s-polarized measurement light reflected in the X direction on the polarization separation surface and the + 1st order diffracted light 31paa that is the p-polarized reference light that has passed through the polarization separation surface are polarized along the same path. The light propagates through the beam splitter PBS and is emitted from the polarization beam splitter PBS.

On the other hand, the s-polarized −1st-order diffracted light 31sb reflected in the X direction by the polarization separation surface of the polarization beam splitter PBS and the p-polarized −1st-order diffracted light 31pb transmitted through the polarization separation surface are along the same path. The light propagates through the polarization beam splitter PBS and enters a folding member 36b such as a corner cube fixedly attached to the polarization beam splitter PBS. The s-polarized −1st-order diffracted light 31sb and the p-polarized −1st-order diffracted light 31pb that have been translated in the Z direction by the action of the folding member 36b and returned to the polarization beam splitter PBS are incident on the polarization separation surface of the polarization beam splitter PBS. To do.

The −1st-order diffracted light 31sb, which is the s-polarized measurement light reflected in the Z direction on the polarization separation surface of the polarization beam splitter PBS, is emitted from the polarization beam splitter PBS and moved from the measurement point 32a on the diffraction grating 10 to the + X direction side. Incident light is incident on the point 32c which is spaced apart. In response to the s-polarized -1st order diffracted light 31sb incident on the point 32c on the diffraction grating 10, the -1st order diffracted light 31sbb is generated along the X direction from the diffraction grating 10. The s-polarized −1st-order diffracted light 31sbb, which is measurement light generated from the diffraction grating 10 along the X direction, is deflected in the Z direction by a deflecting member 33d configured in the same manner as the deflecting members 33a to 33c, and then is polarized. It propagates inside the splitter PBS and is reflected in the X direction by the polarization separation surface.

The first-order diffracted light 31pb, which is p-polarized reference light that has passed through the polarization separation surface of the polarization beam splitter PBS, is emitted from the polarization beam splitter PBS, and is spaced from the point 34a on the reference member RM to the + Z direction side by a point 34c. Is incident on. In a region including the point 34c on the reference member RM, a diffraction pattern having a one-dimensional periodic structure along the Z direction is provided. In response to the p-polarized -1st order diffracted light 31pb incident on the point 34c on the reference member RM, the -1st order diffracted light 31pbb is generated along the Z direction from the reference member RM.

The −1st-order diffracted light 31pbb, which is p-polarized reference light generated along the Z direction from the reference member RM, is deflected in the X direction by a deflecting member 35d configured similarly to the deflecting members 35a to 35c, and then is polarized. It propagates inside the splitter PBS and passes through the polarization separation surface. The −1st order diffracted light 31sbb which is the s-polarized measurement light reflected in the X direction on the polarization separation surface and the −1st order diffracted light 31pbb which is the p-polarized reference light transmitted through the polarization separation surface are along the same path. Then, the light propagates through the polarization beam splitter PBS and is emitted from the polarization beam splitter PBS.

Thus, the interference light between the + 1st order diffracted light 31saa, which is the s-polarized measurement light emitted from the polarization beam splitter PBS along the same path, and the + 1st order diffracted light 31paa, which is the p-polarized reference light, is obtained by photoelectric detection. Interference light between the first detection signal and the −1st order diffracted light 31sbb that is the s-polarized measurement light and the −1st order diffracted light 31pbb that is the p-polarized reference light emitted from the polarization beam splitter PBS along the same path. Based on the difference from the second detection signal obtained by photoelectric detection, the X-direction position of the measurement point 32a on the diffraction grating 10, and consequently the X-direction position of the measurement point 32a of the wafer stage WS is measured. In general, the relative position along the X direction at the measurement point 32a of the wafer stage WS whose relative position with respect to the exposure apparatus main body is variable is measured.

As described above, + 1st order diffracted light 31sc (not shown) and − from the diffraction grating 10 along the Y direction (along the YZ plane) according to the s-polarized light incident on the measurement point 32a on the diffraction grating 10 and − First-order diffracted light 31sd (not shown) is generated. Further, in accordance with the p-polarized light incident on the point 34a on the reference member RM, the + first-order diffracted light 31pc (not shown) and the −1st-order diffracted light 31pd from the reference member RM along the Y direction (along the XY plane). (Not shown) occurs.

The + 1st-order diffracted light 31sc that is the s-polarized measurement light and the + 1st-order diffracted light 31pc that is the p-polarized reference light pass through the paths corresponding to the + 1st-order diffracted light 31sa and the + 1st-order diffracted light 31pa in the X-direction position measurement. + 1st-order diffracted light 31scc (not shown) that is light and + 1st-order diffracted light 31pcc (not shown) that is p-polarized reference light are emitted from the polarization beam splitter PBS along the same path. The −1st order diffracted light 31sd, which is s-polarized measurement light, and the + 1st order diffracted light 31pd, which is p-polarized reference light, pass through paths corresponding to the −1st order diffracted light 31sb and −1st order diffracted light 31pb in the X-direction position measurement. It becomes a −1st order diffracted light 31sdd (not shown) which is a polarized measurement light and a −1st order diffracted light 31pdd (not shown) which is a p-polarized reference light, and is emitted from the polarization beam splitter PBS along the same path.

In this way, the interference light between the + 1st order diffracted light 31scc that is the s-polarized measurement light emitted from the polarization beam splitter PBS along the same path and the + 1st order diffracted light 31pcc that is the p-polarized reference light is obtained by photoelectric detection. Interference light between the third detection signal and the −1st order diffracted light 31sdd which is the s-polarized measurement light emitted from the polarization beam splitter PBS along the same path and the −1st order diffracted light 31pdd which is the p-polarized reference light. Based on the difference from the fourth detection signal obtained by photoelectric detection, the Y-direction position of the measurement point 32a on the diffraction grating 10, and consequently the Y-direction position of the measurement point 32a of the wafer stage WS is measured. In general, the relative position along the Y direction at the measurement point 32a of the wafer stage WS whose relative position with respect to the exposure apparatus main body is variable is measured.

FIG. 4 is a diagram for explaining the measurement principle of the position in the Z direction of the diffraction grating attached to the wafer stage. Referring to FIG. 4, a polarization beam splitter (that is, a polarization beam splitter used for measurement of the X-direction position and the Y-direction position of the diffraction grating 10) PBS fixedly attached to the exposure apparatus main body PBS and p-polarization component in the same optical path. And the measurement light 41 including the s-polarized light component enter along the X direction. Of the measurement light 41 incident on the polarization beam splitter PBS, the s-polarized light reflected in the Z direction on the polarization separation surface propagates through the polarization beam splitter PBS and is fixedly attached to the polarization beam splitter PBS. It passes through a quarter-wave plate 42 as a member, becomes circularly polarized light, and enters a point 43a on the diffraction grating 10 attached to the wafer stage WS.

In response to the circularly polarized light incident on the point 43a on the diffraction grating 10, measurement light 41a, which is zero-order light (regular reflection light), is generated from the diffraction grating 10 along the Z direction. The measurement light 41a generated along the Z direction from the diffraction grating 10 becomes p-polarized light through the quarter-wave plate 42, propagates through the polarization beam splitter PBS, and then passes through the polarization separation surface. Of the measurement light 41 incident on the polarization beam splitter PBS, the p-polarized light transmitted through the polarization separation surface propagates through the polarization beam splitter PBS and is fixedly attached to the polarization beam splitter PBS. After passing through 44, the light becomes circularly polarized light, and is incident on a point 45a on a reference member (that is, a reference member used for measurement of the X-direction position and Y-direction position of the diffraction grating 10) RM fixedly attached to the exposure apparatus main body.

In a region including the point 45a on the reference member RM, a planar reflecting surface along the YZ plane is provided. The circularly-polarized reference light 41b, which is zero-order light reflected at the point 45a on the reference member RM, becomes s-polarized light through the quarter-wave plate 44, propagates inside the polarization beam splitter PBS, and is polarized and separated. Is reflected in the Z direction. The p-polarized measurement light 41a transmitted through the polarization separation surface and the s-polarized reference light 41b reflected in the Z direction on the polarization separation surface propagate through the polarization beam splitter PBS along the same path to each other. The light enters the folding member 46 fixedly attached to the splitter PBS. The p-polarized measurement light 41a and the s-polarized reference light 41b, which have been translated in the X direction by the action of the folding member 46 and returned to the polarization beam splitter PBS, enter the polarization separation surface of the polarization beam splitter PBS.

The p-polarized measurement light 41 a that has passed through the polarization separation surface of the polarization beam splitter PBS propagates through the polarization beam splitter PBS, becomes circularly polarized light via the quarter-wave plate 42, and starts from a point 43 a on the diffraction grating 10. Incident to the point 43b spaced in the + X direction. In response to the circularly polarized light 41 a incident on the point 43 b on the diffraction grating 10, measurement light 41 aa that is zero-order light is generated along the Z direction from the diffraction grating 10. The measurement light 41aa generated along the Z direction from the diffraction grating 10 becomes s-polarized light through the quarter-wave plate 42, propagates through the polarization beam splitter PBS, and is reflected in the X direction by the polarization separation surface.

The s-polarized reference 41b reflected by the polarization separation surface of the polarization beam splitter PBS propagates through the polarization beam splitter PBS, becomes circularly polarized light via the quarter wavelength plate 44, and starts from a point 45a on the reference member RM. The incident light enters the point 45b spaced in the + Z direction. In a region including the point 45b on the reference member RM, a planar reflecting surface along the YZ plane is provided. The circularly polarized reference light 41b reflected at the point 45b on the reference member RM becomes p-polarized light through the quarter-wave plate 44, propagates through the polarization beam splitter PBS, and passes through the polarization separation surface.

The s-polarized measurement light 41aa reflected in the X direction on the polarization separation surface of the polarization beam splitter PBS and the p-polarized reference light 41b transmitted through the polarization separation surface are inside the polarization beam splitter PBS along the same path. And is emitted from the polarization beam splitter PBS. Thus, on the diffraction grating 10 based on the detection signal obtained by photoelectrically detecting the interference light between the s-polarized measurement light 41aa and the p-polarized reference light 41b emitted from the polarization beam splitter PBS along the same path. , The Z-direction position of the measurement point 43 located between the

points

43a and 43b, and thus the Z-direction position of the measurement point 43 on the wafer stage WS is measured. Generally, the relative position along the Z direction is measured at the measurement point 43 of the wafer stage WS whose relative position with respect to the exposure apparatus main body is variable.

FIG. 5 is a diagram schematically showing the configuration of the position measuring apparatus according to the first embodiment. Referring to FIG. 5, the position measurement device 1 of the first embodiment includes four measurement units 11 (only one measurement unit 11 is shown in FIG. 5), a measurement light source 12, a branch unit 13, and a light guide 14. And a processing unit 15. The measurement unit 11 includes a polarization beam splitter PBS, a reference member RM, and an input / output unit 11A, and is fixedly attached to the exposure apparatus main body. As an example, the measurement light source 12, the branch unit 13, the light guide 14, and the processing unit 15 are provided in common for the four measurement units 11.

As the measurement light source 12, a He—Ne laser light source, a semiconductor laser light source, or the like can be used. The light supplied from the measurement light source 12 is separated into s-polarized light and p-polarized light in the branch unit 13, and is input to the input / output unit 11 </ b> A of each measurement unit 11 via, for example, a dual-core light guide 14. Supplied. That is, the s-polarized light propagated through one core of the light guide 14 and the p-polarized light propagated through the other core are supplied to the input / output unit 11A. The input / output unit 11A includes a collimator, a beam splitter, and the like, and generates p-polarized component and s-polarized component along the same optical path from p-polarized light and s-polarized light supplied along different optical paths. The required number of measurement lights are generated. The plurality of measurement lights generated by the input / output unit 11A are respectively emitted along the X direction and enter the polarization beam splitter PBS.

Specifically, on the optical surface PBSa on the input / output unit 11A side of the prism-type polarizing beam splitter PBS, as shown in FIG. 6, four

measurement lights

51, 52, 53, and 54 for measuring the positions in the XY directions are provided. Five

measurement lights

61, 62, 63, 64, 65 for measuring the Z-direction position are incident. As an example, the measurement light 61 is incident on the center of the optical surface PBSa, the measurement lights 51 to 54 are incident on the positions of four corners of a relatively small square centered on the position of the measurement light 61, and the measurement lights 62 to 65 are measured. The light 61 is incident on four corners of a relatively large square centered on the position of the light 61.

Referring to FIG. 5, of the measurement lights 51 to 54, the s-polarized light reflected by the polarization separation surface of the polarization beam splitter PBS is incident on the polarization beam splitter PBS side of the diffraction grating 10, as shown in FIG. It enters the measurement points 51m, 52m, 53m, and 54m on the surface 10a. Among the measurement lights 51 to 54, the p-polarized light that has passed through the polarization separation surface of the polarization beam splitter PBS, as shown in FIG. 8, is the

points

51r and 52r on the incident surface RMa of the reference member RM on the polarization beam splitter PBS side. , 53r, and 54r. In a region including the points 51r to 54r, a diffraction pattern having a two-dimensional periodic structure along the Y direction and the Z direction is provided.

The ± first-order diffracted light, which is s-polarized measurement light generated along the X direction (along the XZ plane) at the measurement point 51m, is an optical surface on the diffraction grating 10 side of the polarization beam splitter PBS as shown in FIG. In the region 51e on the PBSb, it enters the polarization separation surface of the polarization beam splitter PBS via a diffraction pattern region having a one-dimensional periodic structure along the X direction. The ± first-order diffracted light generated along the Y direction (along the YZ plane) at the measurement point 51m passes through the diffraction pattern region having a one-dimensional periodic structure along the Y direction in the region 51e. Incident on the polarization separation surface.

Similarly, ± first-order diffracted light, which is s-polarized measurement light generated along the X direction at measurement points 52m to 54m, extends along the X direction in the

regions

52e, 53e, and 54e on the optical surface PBSb of the polarization beam splitter PBS. Then, the light enters the polarization separation surface of the polarization beam splitter PBS through the diffraction pattern region having the one-dimensional periodic structure. The ± first-order diffracted light generated along the Y direction at the measurement points 52m to 54m passes through the diffraction pattern region having a one-dimensional periodic structure along the Y direction in the regions 52e to 54e, and the polarization separation surface of the polarization beam splitter PBS. Is incident on.

Each measurement light of s-polarized light reflected in the X direction by the polarization separation surface of the polarization beam splitter PBS passes through a folding member such as a corner cube fixedly attached to the polarization beam splitter PBS, and then the inside of the polarization beam splitter PBS. And is incident on the diffraction grating 10 again. That is, the ± first-order diffracted light generated along the X direction at the measurement points 51m to 54m reciprocates once through the path in the polarization beam splitter PBS, and the measurement point 51m to 54m is sandwiched between the measurement points 51m to 54m on the incident surface 10a of the diffraction grating 10. Incident to a pair of points spaced in the direction. The ± first-order diffracted light generated along the Y direction at the measurement points 51m to 54m reciprocates once through the path in the polarization beam splitter PBS, and in the Y direction across the measurement points 51m to 54m on the incident surface 10a of the diffraction grating 10. Incident on a pair of spaced points.

First-order diffracted light, which is s-polarized measurement light generated at a pair of points spaced in the X direction across the measurement point 51m, is primary along the X direction in the region 51e on the optical surface PBSb of the polarization beam splitter PBS. It goes to the polarization separation plane of the polarization beam splitter PBS through the diffraction pattern region having the original periodic structure. First-order diffracted light, which is s-polarized measurement light generated at a pair of points spaced in the Y direction across the measurement point 51m, passes through a diffraction pattern region having a one-dimensional periodic structure along the Y direction in the region 51e. Toward the polarization separation surface of the polarization beam splitter PBS.

Similarly, first-order diffracted light, which is s-polarized measurement light generated at a pair of points spaced in the X direction with the measurement points 52m to 54m interposed therebetween, is a region 52e to 54e on the optical surface PBSb of the polarization beam splitter PBS. At the polarization separation plane of the polarization beam splitter PBS through a diffraction pattern region having a one-dimensional periodic structure along the X direction. The first-order diffracted light, which is s-polarized measurement light generated at a pair of points spaced in the Y direction across the measurement points 52m to 54m, is diffracted having a one-dimensional periodic structure along the Y direction in the regions 52e to 54e. It goes to the polarization separation surface of the polarization beam splitter PBS through the pattern region.

On the other hand, the ± first-order diffracted light that is p-polarized reference light generated along the Z direction (along the XZ plane) at the point 51r on the incident surface RMa of the reference member RM is a polarized beam as shown in FIG. In the region 51f on the optical surface PBSc on the reference member RM side of the splitter PBS, it enters the polarization separation surface of the polarization beam splitter PBS via a diffraction pattern region having a one-dimensional periodic structure along the X direction. The ± first-order diffracted light that is p-polarized reference light generated along the Y direction (along the XY plane) at the measurement point 51r passes through a diffraction pattern region having a one-dimensional periodic structure along the Y direction in the region 51f. Then, the light enters the polarization separation surface of the polarization beam splitter PBS.

Similarly, ± first-order diffracted light, which is p-polarized reference light generated along the X direction at points 52r to 54r on the incident surface RMa of the reference member RM, is converted into

regions

52f and 53f on the surface PBSc of the polarization beam splitter PBS. , 54f is incident on the polarization separation surface of the polarization beam splitter PBS via a diffraction pattern region having a one-dimensional periodic structure along the X direction. The ± first-order diffracted light that is p-polarized reference light generated along the Y direction at the measurement points 52r to 54r is polarized through the diffraction pattern region having a one-dimensional periodic structure along the Y direction in the regions 52f to 54f. The light enters the polarization splitting surface of the beam splitter PBS.

Each p-polarized reference light transmitted through the polarization separation surface of the polarization beam splitter PBS propagates through the polarization member such as the corner cube described above, propagates inside the polarization beam splitter PBS, and is incident on the reference member RM again. That is, the ± first-order diffracted light generated along the Z direction at the points 51r to 54r reciprocates once through the path in the polarization beam splitter PBS, and in the Z direction across the points 51r to 54r on the incident surface RMa of the reference member RM. The light beams are incident on a pair of spaced points 51ra, 51rb; 52ra, 52rb; 53ra, 53rb; 54ra, 54rb. In the region including the points 51ra, 51rb; 52ra, 52rb; 53ra, 53rb; 54ra, 54rb, a diffraction pattern having a one-dimensional periodic structure along the Z direction is provided.

The ± first-order diffracted light generated along the Y direction at the points 51r to 54r reciprocates once through the path in the polarization beam splitter PBS, and is spaced in the Y direction across the points 51r to 54r on the incident surface RMa of the reference member RM. Are incident on a pair of points 51rc, 51rd; 52rc, 52rd; 53rc, 53rd; 54rc, 54rd. A region including the points 51 rc, 51 rd; 52 rc, 52 rd; 53 rc, 53 rd; 54 rc, 54 rd is provided with a diffraction pattern having a one-dimensional periodic structure along the Y direction.

The first-order diffracted light, which is p-polarized reference light generated at a pair of points spaced in the Z direction across the point 51r, is one-dimensional along the Z direction in the region 51f on the optical surface PBSc of the polarizing beam splitter PBS. It goes to the polarization separation surface of the polarization beam splitter PBS through the diffraction pattern region having the periodic structure. First-order diffracted light, which is p-polarized reference light generated at a pair of points spaced in the Y direction across the point 51r, passes through a diffraction pattern region having a one-dimensional periodic structure along the Y direction in the region 51f. , Toward the polarization separation surface of the polarization beam splitter PBS.

Similarly, the first-order diffracted light, which is p-polarized reference light generated at a pair of points spaced in the Z direction across the points 52r to 54r, is Z in the regions 52f to 54f on the surface PBSc of the polarization beam splitter PBS. It goes to the polarization separation surface of the polarization beam splitter PBS through a diffraction pattern region having a one-dimensional periodic structure along the direction. First-order diffracted light, which is p-polarized reference light generated at a pair of points spaced in the Y direction across the points 52r to 54r, is a diffraction pattern having a one-dimensional periodic structure along the Y direction in the regions 52f to 54f. It goes to the polarization separation plane of the polarization beam splitter PBS through the region.

For each of the measurement beams 51 to 54, the optical path between the diffraction grating 10 and the optical path between the s-polarized measurement light reflected in the X direction by the polarization separation surface and the optical path between the reference member RM is reciprocated twice. The p-polarized reference light transmitted through the polarization splitting surface is emitted from the polarization beam splitter PBS along the same path. Thus, the

interference lights

51a, 51b, 51c, 51d of the measurement light corresponding to the measurement light 51 and the reference light are emitted from the polarization beam splitter PBS along the same path and enter the input / output unit 11A.

Similarly, the

interference lights

52a, 52b, 52c, 52d; 53a, 53b, 53c, 53d; 54a, 54b, 54c, 54d of the measurement light and the reference light corresponding to the measurement lights 52 to 54 are along the same path. Is emitted from the polarization beam splitter PBS and enters the input / output unit 11A. The interference lights 51a to 54a and 51b to 54b related to the measurement in the X direction are shown in FIG. 5, but the illustration of the interference lights 51c to 54c and 51d to 54d related to the measurement in the Y direction is omitted. .

The input / output unit 11A supplies a detection signal obtained by photoelectrically detecting each interference light to the processing unit 15. The processing unit 15 obtains the X-direction position of the measurement point 51m on the diffraction grating 10 based on the difference between the detection signal obtained by photoelectrically detecting the interference light 51a and the detection signal obtained by photoelectric detection of the interference light 51b. Based on the difference between the detection signal obtained by photoelectrically detecting the interference light 51c and the detection signal obtained by photoelectric detection of the interference light 51d, the position in the Y direction of the measurement point 51m on the diffraction grating 10 is obtained.

Similarly, the processing unit 15 measures the measurement points on the diffraction grating 10 based on the difference between the detection signal obtained by photoelectric detection of the interference lights 52a to 54a and the detection signal obtained by photoelectric detection of the interference lights 52b to 54b. Based on the difference between the detection signal obtained by photoelectrically detecting the interference lights 52c to 54c and the detection signal obtained by photoelectric detection of the interference lights 52d to 54d, the X-direction positions of 52m to 54m are obtained. The Y direction positions of the measurement points 52m to 54m are obtained. Measurement results of the X direction position and the Y direction position of the measurement points 51m to 54m on the diffraction grating 10 obtained by the processing unit 15, and consequently the measurement result of the X direction position and the Y direction position at the measurement points 51m to 54m of the wafer stage WS. Is supplied to the control system CR.

Referring to FIG. 5 again, of the measurement lights 61 to 65, the s-polarized light reflected by the polarization separation surface of the polarization beam splitter PBS is fixed to the optical surface PBSb of the polarization beam splitter PBS as shown in FIG. The circularly polarized light passes through quarter-

wave plates

61e, 62e, 63e, 64e, and 65e attached thereto. As shown in FIG. 7, the light that has been circularly polarized through the quarter-wave plates 61e to 65e enters the vicinity of the measurement points 61m, 62m, 63m, 64m, and 65m on the incident surface 10a of the diffraction grating 10. .

Among the measurement lights 61 to 65, the p-polarized light that has passed through the polarization separation surface of the polarization beam splitter PBS is fixedly attached to the optical surface PBSc of the polarization beam splitter PBS, as shown in FIG. It becomes circularly polarized light through the

wave plates

61f, 62f, 63f, 64f, and 65f. As shown in FIG. 8, the light that has been circularly polarized through the quarter-wave plates 61f to 65f enters the vicinity of

points

61r, 62r, 63r, 64r, and 65r on the incident surface RMa of the reference member RM. In a region including the points 61r to 65r, a reflecting surface along the YZ plane is provided.

In response to the circularly polarized light incident in the vicinity of the measurement points 61 m to 65 m on the diffraction grating 10, measurement light that is zero-order light is generated along the Z direction from the diffraction grating 10. Circularly polarized measurement light generated along the Z direction from the diffraction grating 10 becomes p-polarized light through the quarter-wave plates 61e to 65e, and enters the polarization separation surface of the polarization beam splitter PBS. Circularly polarized reference light, which is zero-order light reflected in the vicinity of the points 61r to 65r on the reference member RM, becomes s-polarized light through the quarter-wave plates 61f to 65f, and is a polarization separation surface of the polarization beam splitter PBS. Is incident on.

Each p-polarized measurement light that has passed through the polarization separation surface of the polarization beam splitter PBS becomes circularly polarized light through the corresponding folding member, the polarization beam splitter PBS, and the quarter wavelength plates 61e to 65e, and again on the diffraction grating 10. In the vicinity of the measurement points 61m to 65m. In response to circularly polarized light that has entered the vicinity of the measurement points 61 m to 65 m on the diffraction grating 10, measurement light that is zero-order light is generated along the Z direction from the diffraction grating 10. Circularly polarized measurement light generated from the diffraction grating 10 along the Z direction passes through the quarter-wave plates 61e to 65e to become s-polarized light, and travels toward the polarization separation surface of the polarization beam splitter PBS.

Each s-polarized reference light reflected in the Z direction by the polarization separation surface of the polarization beam splitter PBS becomes circularly polarized light through the corresponding folding member, the polarization beam splitter PBS, and the quarter wavelength plates 61f to 65f, and again. Incident near the points 61r to 65r on the reference member RM. The circularly polarized reference light reflected in the vicinity of the points 61r to 65r on the reference member RM becomes p-polarized light through the quarter-wave plates 61f to 65f and travels toward the polarization separation surface of the polarization beam splitter PBS.

For each of the measurement lights 61 to 65, the s-polarized measurement light reflected in the X direction on the polarization separation surface of the polarization beam splitter PBS after reciprocating the optical path between the diffraction grating 10 and the reference member RM. The p-polarized reference light that travels back and forth in the optical path and passes through the polarization separation surface is emitted from the polarization beam splitter PBS along the same path. Thus, the

interference lights

61a, 62a, 63a, 64a, 65a between the measurement light and the reference light corresponding to the measurement lights 61 to 65 are emitted from the polarization beam splitter PBS along the same path and enter the input / output unit 11A. To do.

The input / output unit 11A supplies a detection signal obtained by photoelectrically detecting the interference lights 61a to 65a to the processing unit 15. The processing unit 15 obtains the Z-direction positions of the measurement points 61m to 65m on the diffraction grating 10 based on detection signals obtained by photoelectrically detecting the interference lights 61a to 65a. The measurement results of the Z direction positions of the measurement points 61m to 65m on the diffraction grating 10 obtained by the processing unit 15, and the measurement results of the Z direction positions of the measurement points 61m to 65m of the wafer stage WS are supplied to the control system CR. The

Note that the wafer stage WS holding the wafer W is stepped over a predetermined range along the XY plane during exposure. In the first embodiment, the four measurement units 11 and the pair of reflective diffraction gratings 10 always measure the position of the wafer stage WS by the cooperative action of at least one measurement unit 11 and the diffraction grating 10 facing the measurement units 11. Arranged to be able to do. In general, various forms are possible for the number and arrangement of measurement units, the number and arrangement of diffraction gratings, and the like.

As described above, the position measuring apparatus 1 according to the first embodiment measures the relative position of the wafer stage (second member) WS whose relative position with respect to the exposure apparatus main body (first member) is variable. Specifically, the position measuring apparatus 1 has a polarization beam splitter PBS and a reference member RM fixedly attached to the exposure apparatus main body, and a two-dimensional periodic structure attached to the wafer stage WS along the X direction and the Y direction. And a reflective diffraction grating 10.

The position measuring apparatus 1 uses the single polarization beam splitter PBS fixedly attached to the exposure apparatus main body, the X direction position and the Y direction position at the measurement points 51m to 54m of the wafer stage WS, and the wafer stage. The positions in the Z direction at WS measurement points 61m to 65m are simultaneously measured by a so-called heterodyne interference method. As a result, in addition to the X-direction position, the Y-direction position, and the Z-direction position at a plurality of points on the wafer stage WS, the rotation position of the wafer stage WS around the X-axis, the rotation position around the Y-axis, and the Z-axis position The position of rotation is also measured at the same time.

As described above, in the position measurement apparatus 1 according to the first embodiment, the X direction and the Y direction which are in-plane directions of the wafer W using the single polarization beam splitter PBS fixedly attached to the exposure apparatus main body. The position measurement of the wafer stage WS along the direction and the position measurement of the wafer stage WS along the Z direction which is the normal direction of the wafer W can be performed simultaneously and stably. Therefore, in the exposure apparatus of the first embodiment, the position measurement apparatus 1 that simultaneously and stably measures the position of the wafer stage WS is used to accurately place the wafer W on the wafer stage WS with respect to the projection optical system PL. It is possible to align the positions, and thus it is possible to perform a good projection exposure.

In the first embodiment described above, the position measuring apparatus of the present invention is applied to the position measurement of the wafer stage WS that holds and moves the wafer W in the exposure apparatus. However, the present invention is not limited to a wafer stage (substrate stage), and in general, the position measuring apparatus of the present invention can be similarly applied to position measurement of a stage that holds and moves an object. As an example, for example, as shown in FIG. 11, the position measuring device of the present invention is applied to position measurement of a mask stage MS that holds and moves a mask M provided with a pattern to be transferred in the first embodiment. You can also

In the step-and-scan method, the mask stage MS holding the mask M moves along the Y direction that is the scanning direction. The position measuring apparatus 1 according to the modification of FIG. 11 includes a pair of reflective diffraction gratings 10 placed at an interval in the X direction with the mask M interposed therebetween, and the mask M (and thus the projection optical system PL). And a pair of measuring units 11 installed at an interval in the X direction. FIG. 11 shows a reference state in which the center PAa of the pattern area PA of the mask M and the optical axis AX of the projection optical system PL are at the same position on the XY plane.

The diffraction grating 10 has an elongated rectangular outer shape, for example, along the Y direction, and is fixedly (or detachably) attached to the mask stage MS. The pair of measurement units 11 is fixedly attached to the exposure apparatus main body isolated from the mask stage MS. As an example, the pair of diffraction gratings 10 are arranged symmetrically with respect to an axis extending in the Y direction through the center PAa of the pattern area PA of the mask M, and have the same configuration. The pair of measurement units 11 are arranged symmetrically with respect to the axis extending in the Y direction through the optical axis AX so as to be along the axis extending in the X direction through the optical axis AX of the projection optical system PL, and have the same configuration as each other. Have

In the first embodiment described above, the polarization beam splitter PBS is attached to the exposure apparatus main body, the diffraction grating 10 is attached to the wafer stage WS, and the relative position of the wafer stage WS that is variable relative to the exposure apparatus main body is determined. Measuring. However, the present invention is not limited thereto, and in general, in order to measure the relative position of the second member whose relative position with respect to the first member is variable, a polarization beam splitter fixedly attached to the first member, A diffraction grating attached to two members can be used. For example, in the first embodiment described above, the polarization beam splitter PBS is attached to the wafer stage WS, the diffraction grating 10 is attached to the exposure apparatus body, and the relative position of the wafer stage WS whose relative position with respect to the exposure apparatus body is variable is measured. You can also In addition, when the position measurement apparatus of the present invention is applied to the position measurement of a stage that moves while holding an object, one of the polarization beam splitter and the diffraction grating is attached to the stage. Further, the diffraction grating 10 may be provided on the back surface of the wafer stage WS, and the polarization beam splitter PBS may be disposed on the surface plate side from the wafer stage.

Further, in the above-described first embodiment, the exposure apparatus is based on the interference light between the measurement light that has reciprocated twice along the optical path between the diffraction grating 10 and the reference light that has reciprocated twice along the optical path between the reference member RM. The relative position of the wafer stage WS whose relative position with respect to the main body is variable is measured. However, the measurement target member is not limited to this, for example, based on the interference light between the measurement light that reciprocates once in the optical path between the diffraction grating and the reference light that reciprocates once in the optical path between the reference member. The relative position of can also be measured.

FIG. 12 is a view schematically showing a configuration of an exposure apparatus provided with the position measuring apparatus according to the second embodiment. FIG. 13 is a diagram schematically showing the arrangement of diffraction gratings and measurement units that constitute the position measurement apparatus of the second embodiment. The second embodiment has a configuration similar to that of the first embodiment, but the configuration of the position measuring device 1A according to the second embodiment is different from the position measuring device 1 of the first embodiment. Therefore, in FIG. 12 and FIG. 13, the elements having the same functions as those shown in FIG. 1 and FIG. Hereinafter, the configuration and operation of the second embodiment will be described focusing on differences from the first embodiment.

The exposure apparatus according to the second embodiment includes a position in the X direction, a position in the Y direction, a position in the Z direction, a position in the rotational direction around the X axis, and a position in the rotational direction around the Y axis of the wafer stage WS (and thus the wafer W). And a position measuring device 1A that measures the position in the rotation direction around the Z axis in real time. As shown in FIGS. 12 and 13, the position measuring apparatus 1 </ b> A includes a pair of reflective diffraction gratings 110 that are installed with a gap in the X direction with the wafer W interposed therebetween, and the projection optical system PL with the X direction interposed therebetween. And four measuring units 111 installed side by side. FIG. 13 shows a reference state in which the center Wa of the wafer W and the optical axis AX of the projection optical system PL are at the same position in the XY plane.

The diffraction grating 110 has, for example, an elongated rectangular outer shape along the Y direction, and is fixedly (or detachably) attached to the wafer stage WS. The four measurement units 111 are fixedly attached to the exposure apparatus main body isolated from the wafer stage WS. Of the four measurement units 111, the first pair of measurement units 111 are arranged side by side in the X direction on the + X direction side of the projection optical system PL, and the second pair of measurement units 111 are -X of the projection optical system PL. They are arranged side by side in the X direction on the direction side.

Hereinafter, in order to simplify the description, it is assumed that the pair of diffraction gratings 110 are arranged symmetrically with respect to an axis extending in the Y direction through the center Wa of the wafer W and have the same configuration. The four measuring units 111 are symmetrically arranged with respect to the axis extending in the Y direction through the optical axis AX so as to be along the axis extending in the X direction through the optical axis AX of the projection optical system PL, and have the same configuration as each other. It shall have. Further, it is assumed that the wafer stage WS moves with respect to the stationary exposure apparatus main body.

Hereinafter, the measurement principle of the position measurement apparatus 1A will be described prior to the description of the specific configuration and operation of the position measurement apparatus 1A. FIG. 14 is a diagram for explaining the measurement principle of the X-direction position and the Y-direction position of the diffraction grating attached to the wafer stage. Referring to FIG. 14, measurement light 131 including a p-polarized component and an s-polarized component enters the same optical path along the X direction on a polarizing beam splitter PBS fixedly attached to the exposure apparatus body. Further, along the optical path spaced in the + Z direction from the optical path of the measurement light 131, the measurement light 132 including the p-polarized component and the s-polarized component is incident along the X direction on the same optical path.

Of the measurement light 131 incident on the polarization beam splitter PBS, s-polarized light reflected in the Z direction on the polarization separation surface propagates inside the polarization beam splitter PBS and enters the quarter-wave plate 133. The light that has been circularly polarized through the quarter-wave plate 133 is deflected obliquely with respect to the Z direction in the XZ plane by the deflecting member 134a, and then the reflective diffraction grating 110 attached to the wafer stage WS. The incident light is obliquely incident on the upper dotted area (hereinafter, simply referred to as “area”) 135 a at the Littrow angle of the diffraction grating 110.

The quarter wave plate 133 as a polarizing member is attached so as to be in contact with the optical surface PBSa along the XY plane of the polarizing beam splitter PBS. The deflecting member 134a is attached to a required position on the quarter wavelength plate 133 and has a one-dimensional periodic structure diffraction pattern along the X direction. The diffraction grating 110 has a form of a plane parallel plate with an incident surface substantially parallel to the XY plane with respect to the polarization beam splitter PBS. The diffraction grating 110 is provided with a diffraction pattern having a two-dimensional periodic structure along the X direction and the Y direction.

In response to light obliquely incident on the region 135a on the diffraction grating 110 with the Littrow angle of the diffraction grating 110, the first-order diffracted light 131a is generated obliquely from the diffraction grating 110 along the same optical path as the incident light path to the diffraction grating 110. To do. The minus first-order diffracted light 131a, which is circularly polarized measurement light generated from the diffraction grating 110 in an oblique direction, is deflected in the Z direction by the deflecting member 134a, then becomes p-polarized light through the quarter-wave plate 133, and is polarized light. It propagates inside the splitter PBS and passes through the polarization separation surface.

The Littrow angle (Littrow angle of the first-order diffracted light) of the diffraction grating 110 is the incident angle of the light beam when the light beam incident on the diffraction grating 110 and the first-order diffracted light generated corresponding to the incident beam are parallel to each other. Is defined as When the light beam is incident on the diffraction grating 110 at the Littrow angle, even if the height (Z-direction position) of the grating pattern surface of the diffraction grating 110 changes, the lateral shift of the first-order diffracted light does not occur. There is an advantage of not.

Of the measurement light 131 incident on the polarization beam splitter PBS, the p-polarized light transmitted through the polarization separation surface propagates inside the polarization beam splitter PBS and enters the quarter-wave plate 136. The quarter wave plate 136 as a polarizing member is attached so as to be in contact with the optical surface PBSb along the YZ plane of the polarizing beam splitter PBS. The light that has been circularly polarized through the quarter-wave plate 136 is incident on a planar reflecting surface 137 provided in contact with the quarter-wave plate 136. The circularly-polarized reference light 131b reflected by the reflecting surface 137 becomes s-polarized light through the quarter-wave plate 136, propagates through the polarization beam splitter PBS, and is reflected in the Z direction by the polarization separation surface.

In the configuration of FIG. 14, the reflective surface 137 as the reference surface of the reference member RM is provided so as to contact the quarter wavelength plate 136, but the quarter wavelength plate 136 is not limited thereto. A mirror having a reflective surface 137 at a distance from each other may be disposed as the reference member RM. In other words, the reference member RM may be a mirror having the form of a plane parallel plate with the incident surface along the YZ plane facing the polarization beam splitter PBS. In this case, the reference member RM is fixedly attached to the exposure apparatus body in the same manner as the polarization beam splitter PBS.

The p-polarized measurement light (−1st-order diffracted light) 131a transmitted through the polarization separation surface of the polarization beam splitter PBS and the s-polarized reference light (0th-order reflected light) 131b reflected by the polarization separation surface are on the same path. And propagates through the inside of the polarization beam splitter PBS, and enters the folding member 138a such as a corner cube attached to the polarization beam splitter PBS. The p-polarized measurement light 131a and the s-polarized reference light 131b that have been translated in the + X direction by the action of the folding member 138a and returned to the polarization beam splitter PBS are incident on the polarization separation surface of the polarization beam splitter PBS.

The p-polarized measurement light 131 a that has passed through the polarization separation surface propagates through the polarization beam splitter PBS and enters the quarter-wave plate 133. The measurement light 131 a that has been circularly polarized through the quarter-wave plate 133 is incident on the diffraction grating 110 obliquely at a Littrow angle of the diffraction grating 110 into a region 135 b spaced from the region 135 a in the + X direction. In response to the light 131a obliquely incident on the region 135b on the diffraction grating 110 at the Littrow angle of the diffraction grating 110, the minus first-order diffracted light 131aa is obliquely directed from the diffraction grating 110 along the same optical path as the incident light path to the diffraction grating 110. appear.

An incident path of light incident on the region 135a on the diffraction grating 110 (and thus an emission path through which the −1st order diffracted light 131a is emitted) and an incident path of light incident on the region 135b (and thus the −1st order diffracted light 131aa are emitted). Are parallel to each other. The −1st-order diffracted light 131aa, which is a circularly polarized measurement light generated from the diffraction grating 110 in an oblique direction, is deflected in the Z direction by the deflecting member 134a, then becomes s-polarized light through the quarter-wave plate 133, and the polarized beam It propagates inside the splitter PBS and is reflected in the X direction by the polarization separation surface.

The s-polarized reference light 131 b reflected in the X direction by the polarization separation surface of the polarization beam splitter PBS propagates through the polarization beam splitter PBS and enters the quarter wavelength plate 136. The reference light 131b that has been circularly polarized through the quarter-wave plate 136 is reflected by the reflecting surface 137 as a reference surface, and then becomes p-polarized light through the quarter-wave plate 136, and the inside of the polarization beam splitter PBS. Is transmitted through the polarization splitting surface. The s-polarized measurement light 131aa reflected in the X direction on the polarization separation surface and the p-polarized reference light 131b transmitted through the polarization separation surface propagate through the polarization beam splitter PBS along the same path, and are polarized. Ejected from the beam splitter PBS.

On the other hand, of the measurement light 132 incident on the polarization beam splitter PBS, the s-polarized light reflected in the Z direction on the polarization separation surface propagates inside the polarization beam splitter PBS and enters the quarter wavelength plate 133. . The light that has been circularly polarized through the quarter-wave plate 133 is deflected obliquely with respect to the Z direction in the YZ plane by the deflecting member 134b, and then the Littrow of the diffraction grating 110 in the region 135c on the diffraction grating 110. Incident at an angle. Similarly to the deflection member 134a, the deflection member 134b is attached to a required position on the quarter-wave plate 133 and has a one-dimensional periodic structure diffraction pattern along the X direction.

In accordance with the light obliquely incident on the region 135c on the diffraction grating 110 at the Littrow angle of the diffraction grating 110, the first-order diffracted light 132a is generated obliquely from the diffraction grating 110 along the same optical path as the incident light path to the diffraction grating 110. . An incident path of light incident on the region 135a on the diffraction grating 110 (and thus an exit path from which the −1st order diffracted light 131a is emitted) and an incident path of light incident on the region 135c (and an exit from which the + 1st order diffracted light 132a is emitted). The path) is symmetric with respect to a plane parallel to the YZ plane through an intermediate position between the region 135a and the region 135c. The + 1st-order diffracted light 132a, which is circularly polarized measurement light generated in the oblique direction from the diffraction grating 110, is deflected in the Z direction by the deflecting member 134b, then becomes p-polarized light through the quarter-wave plate 133, and is polarized beam splitter. Propagates through the PBS and passes through the polarization separation surface.

Of the measurement light 132 incident on the polarization beam splitter PBS, the p-polarized light transmitted through the polarization separation surface propagates inside the polarization beam splitter PBS and enters the quarter-wave plate 136. The light that has been circularly polarized through the quarter-wave plate 136 enters a reflecting surface 137 as a reference surface of the reference member RM. The circularly-polarized reference light 132b reflected by the reflecting surface 137 becomes s-polarized light through the quarter-wave plate 136, propagates through the polarization beam splitter PBS, and is reflected in the Z direction by the polarization separation surface.

The p-polarized measurement light 132a transmitted through the polarization separation surface of the polarization beam splitter PBS and the s-polarized reference light 132b reflected by the polarization separation surface propagate through the polarization beam splitter PBS along the same path. Then, the light enters the folding member 138b such as a corner cube attached to the polarization beam splitter PBS. The p-polarized measurement light 132a and the s-polarized reference light 132b that have been translated in the + X direction and returned to the polarization beam splitter PBS by the action of the folding member 138b are incident on the polarization separation surface of the polarization beam splitter PBS.

The p-polarized measurement light 132a that has passed through the polarization separation surface of the polarization beam splitter PBS propagates through the polarization beam splitter PBS and enters the quarter-wave plate 133. The measurement light 132 a that has become circularly polarized light through the quarter-wave plate 133 is incident obliquely at a Littrow angle of the diffraction grating 110 on the diffraction grating 110 to a region 135 d that is spaced from the region 135 c in the + X direction. In response to the light 132a obliquely incident on the region 135d on the diffraction grating 110 at the Littrow angle of the diffraction grating 110, the first-order diffracted light 132aa is generated obliquely from the diffraction grating 110 along the same optical path as the incident light path to the diffraction grating 110. To do.

An incident path of light incident on the region 135c on the diffraction grating 110 (and thus an exit path from which the + 1st order diffracted light 132a is emitted) and an incident path of light incident on the region 135d (and an exit path from which the + 1st order diffracted light 132aa is emitted). Are parallel to each other. The + 1st-order diffracted light 132aa, which is circularly polarized measurement light generated in the oblique direction from the diffraction grating 110, is deflected in the Z direction by the deflecting member 134b, and then becomes s-polarized light through the quarter-wave plate 133, and the polarization beam splitter. It propagates inside the PBS and is reflected in the X direction by the polarization separation surface.

The s-polarized reference light 132 b reflected in the X direction by the polarization separation surface of the polarization beam splitter PBS propagates inside the polarization beam splitter PBS and enters the quarter-wave plate 136. The reference light 132b that has been circularly polarized through the quarter-wave plate 136 is reflected by the reflecting surface 137, then becomes p-polarized light through the quarter-wave plate 136, propagates inside the polarization beam splitter PBS, Transmits through the polarization separation surface. The s-polarized measurement light 132aa reflected in the X direction on the polarization separation surface and the p-polarized reference light 132b transmitted through the polarization separation surface propagate through the polarization beam splitter PBS along the same path, and are polarized. Ejected from the beam splitter PBS.

Thus, the interference light between the s-polarized measurement light (−1st order diffracted light) 131aa and the p-polarized reference light 131b emitted from the polarization beam splitter PBS along the same path corresponding to the measurement light 131 is photoelectrically detected. Between the first detection signal obtained in this manner and the s-polarized measurement light (+ 1st order diffracted light) 132aa and the p-polarized reference light 132b emitted from the polarization beam splitter PBS along the same path corresponding to the measurement light 132. Based on the difference from the second detection signal obtained by photoelectrically detecting the interference light, the X-direction position of the measurement point 135 on the diffraction grating 110 and, consequently, the X-direction position at the measurement point 135 of the wafer stage WS are measured. In general, the relative position along the X direction at the measurement point 135 of the wafer stage WS whose relative position with respect to the exposure apparatus main body is variable is measured. The measurement point 135 is an intermediate position between the area 135a and the area 135d (as a result, an intermediate position between the area 135b and the area 135c).

In the configuration shown in FIG. 14, s-polarized measurement light (−) corresponds to a pair of measurement light beams 131 and 132 that enter the polarization beam splitter PBS along a pair of X-direction optical paths spaced in the Z direction. Interference light between the first-order diffracted light) 131aa and the p-polarized reference light 131b, and interference light between the s-polarized measurement light (+ 1st-order diffracted light) 132aa and the p-polarized reference light 132b are detected. Similarly, although illustration of reference numerals and the like is omitted, s-polarized light corresponding to the pair of measurement beams 131y and 132y incident on the polarization beam splitter PBS along the pair of X-direction optical paths spaced in the Y-direction. Interference light between measurement light (−1st order diffracted light) 131yaa and p-polarized reference light 131yb, and interference light between s-polarized measurement light (+ 1st order diffracted light) 132yaa and p-polarized reference light 132yb can be detected. .

Therefore, similarly to the measurement of the position in the X direction, the interference between the s-polarized measurement light 131yaa and the p-polarized reference light 131yb emitted from the polarization beam splitter PBS along the same path corresponding to the measurement light 131y. A third detection signal obtained by photoelectrically detecting light and an s-polarized measurement light 132yaa and a p-polarized reference light 132yb emitted from the polarization beam splitter PBS along the same path corresponding to the measurement light 132y. Based on the difference from the fourth detection signal obtained by photoelectrically detecting the interference light, the position in the Y direction of the measurement point 135y on the diffraction grating 110, and hence the position in the Y direction at the measurement point 135y of the wafer stage WS are measured. In general, the relative position along the Y direction at the measurement point 135y of the wafer stage WS whose relative position with respect to the exposure apparatus main body is variable is measured. As will be described later, the measurement point 135y at the Y direction position may coincide with the measurement point 135x at the X direction position (the above-described measurement point 135).

FIG. 15 is a diagram for explaining the measurement principle of the position in the Z direction of the diffraction grating attached to the wafer stage. Referring to FIG. 15, a polarization beam splitter (that is, a polarization beam splitter used for measuring the X-direction position and the Y-direction position of the diffraction grating 110) PBS fixedly attached to the exposure apparatus main body PBS, and p-polarization component in the same optical path. And the measurement light 141 including the s-polarized component are incident along the X direction. Of the measurement light 141 incident on the polarization beam splitter PBS, the s-polarized light reflected in the Z direction on the polarization separation surface propagates inside the polarization beam splitter PBS and is optical along the XY plane of the polarization beam splitter PBS. A quarter-wave plate 133 (that is, a quarter-wave plate used for measurement of the X-direction position and the Y-direction position of the diffraction grating 110) mounted so as to be in contact with the surface PBSa becomes circularly polarized light, and is applied to the wafer stage WS. The light enters the region 143 a on the attached diffraction grating 110.

In response to the circularly polarized light that has entered the region 143a on the diffraction grating 110, measurement light 141a that is zero-order light (regular reflection light) is generated along the Z direction from the diffraction grating 110. The measurement light 141a generated along the Z direction from the diffraction grating 110 becomes p-polarized light through the quarter-wave plate 133, propagates through the polarization beam splitter PBS, and then passes through the polarization separation surface. Of the measurement light 141 incident on the polarization beam splitter PBS, the p-polarized light transmitted through the polarization separation surface propagates through the polarization beam splitter PBS and contacts the optical surface PBSb along the YZ plane of the polarization beam splitter PBS. The quarter-wave plate 136 (that is, a quarter-wave plate used for measuring the X-direction position and the Y-direction position of the diffraction grating 110) is circularly polarized and is in contact with the quarter-wave plate 136. Is incident on the planar reflecting surface 137 (that is, a reference surface used for measurement of the X-direction position and the Y-direction position of the diffraction grating 110).

As described above, the polarizing beam splitter PBS, the quarter-

wave plates

133 and 136, and the reflecting surface 137 as the reference member RM in FIG. 15 are common to the components in FIG. The circularly-polarized reference light 141b reflected by the reflecting surface 137 becomes s-polarized light through the quarter-wave plate 136, propagates through the polarization beam splitter PBS, and is reflected in the Z direction by the polarization separation surface. The p-polarized measurement light 141a transmitted through the polarization separation surface of the polarization beam splitter PBS and the s-polarized reference light 141b reflected in the Z direction by the polarization separation surface pass through the inside of the polarization beam splitter PBS along the same path. Propagate and enter the folding member 146 attached to the polarization beam splitter PBS. The p-polarized measurement light 141a and the s-polarized reference light 141b that have been translated in the + X direction by the action of the folding member 146 and returned to the polarization beam splitter PBS are incident on the polarization separation surface of the polarization beam splitter PBS.

The p-polarized measurement light 141 a that has passed through the polarization separation surface of the polarization beam splitter PBS propagates through the polarization beam splitter PBS, becomes circularly polarized light via the quarter-wave plate 133, and from the region 143 a on the diffraction grating 110. The light enters the region 143b spaced in the + X direction. In response to the circularly polarized light 141 a incident on the region 143 b on the diffraction grating 110, measurement light 141 aa that is zero-order light is generated along the Z direction from the diffraction grating 110. The measurement light 141aa generated along the Z direction from the diffraction grating 110 becomes s-polarized light through the quarter-wave plate 133, propagates inside the polarization beam splitter PBS, and is reflected in the X direction by the polarization separation surface.

The s-polarized reference light 141b reflected by the polarization separation surface of the polarization beam splitter PBS propagates through the polarization beam splitter PBS, becomes circularly polarized light through the quarter wavelength plate 136, and is a reflection surface 137 that is a reference surface. Is incident on. The circularly-polarized reference light 141b reflected by the reflecting surface 137 becomes p-polarized light through the quarter-wave plate 136, propagates through the polarization beam splitter PBS, and passes through the polarization separation surface. The s-polarized measurement light 141aa reflected in the X direction by the polarization separation surface of the polarization beam splitter PBS and the p-polarization reference light 141b transmitted through the polarization separation surface are arranged along the same path with each other in the polarization beam splitter PBS. And is emitted from the polarization beam splitter PBS.

Thus, on the diffraction grating 110 based on the detection signal obtained by photoelectrically detecting the interference light between the s-polarized measurement light 141aa and the p-polarized reference light 141b emitted from the polarization beam splitter PBS along the same path. , The Z-direction position of the measurement point 143 located between the area 143a and the area 143b, and thus the Z-direction position of the measurement point 143 on the wafer stage WS is measured. Generally, the relative position along the Z direction is measured at the measurement point 143 of the wafer stage WS whose relative position with respect to the exposure apparatus main body is variable.

FIG. 16 is a diagram schematically showing the configuration of the position measuring apparatus according to the second embodiment. Referring to FIG. 16, the position measurement apparatus 1A of the second embodiment includes four measurement units 111 (only one measurement unit 111 is shown in FIG. 16), a measurement light source 112, a branch unit 113, and a light guide 114. And a processing unit 115. The measurement unit 111 includes a polarizing beam splitter PBS, quarter-

wave plates

133 and 136, deflecting

members

134a and 134b, a reflecting surface 137 as a reflecting surface of the reference member RM,

folding members

138a, 138b, and 146, and an input / output unit 111A. And is fixedly attached to the exposure apparatus main body. However, in FIG. 16, the

deflection members

134 a and 134 b and the

folding members

138 a, 138 b, and 146 that constitute a part of the measurement unit 111 are not illustrated for the sake of clarity. As an example, the measurement light source 112, the branch unit 113, the light guide 114, and the processing unit 115 are provided in common for the four measurement units 111.

As the measurement light source 112, a He—Ne laser light source, a semiconductor laser light source, or the like can be used. The light supplied from the measurement light source 112 is separated into s-polarized light and p-polarized light in the branch unit 113, and is input to the input / output unit 111A of each measurement unit 111 via, for example, a dual-core light guide 114. Supplied. That is, the s-polarized light propagated through one core of the light guide 114 and the p-polarized light propagated through the other core are supplied to the input / output unit 111A. The input / output unit 111A includes a collimator, a beam splitter, and the like, and generates p-polarized component and s-polarized component along the same optical path from p-polarized light and s-polarized light supplied along different optical paths. The required number of measurement lights are generated. The plurality of measurement lights generated by the input / output unit 111A are respectively emitted along the X direction and enter the polarization beam splitter PBS.

Specifically, on the optical surface of the prism type polarization beam splitter PBS on the input / output unit 111A side, four sets of

measurement light

151x, 152x, 153x, 154x for measuring the X direction position, and four sets of Y direction position measurement.

Measurement light

151y, 152y, 153y, 154y and five measurement lights 161, 162, 163, 164, 165 for measuring the Z-direction position are incident. The measurement lights 151x to 154x correspond to the pair of

measurement lights

131 and 132 in FIG. The measurement lights 151y to 154y correspond to the pair of measurement lights 131y and 132y for Y-direction position measurement described above with reference to FIG. The measurement lights 161 to 165 correspond to the measurement light 141 in FIG.

However, in FIG. 16, for the sake of clarity, the paths to the measurement points 135xa, 135xb, 135xc, and 135xd where the X direction positions are measured by the measurement lights 151x to 154x, and the Y direction by the measurement lights 151y to 154y, respectively. A route to the measurement points 135ya, 135yb, 135yc, and 135yd where the position is measured is represented by a solid line in the drawing. In addition, the path to the

measurement points

143a, 143b, 143c, 143d, and 143e where the position in the Z direction is measured by the measurement lights 161 to 165 is represented by a single line in the form of a broken line in the figure. In the second embodiment, as an example, as shown in FIG. 17, four measurement points 135xa to 135xd and corresponding four measurement points 135ya to 135yd are respectively coincident with each other. In FIG. 17, the positions of the measurement points 135xa to 135xd, 135ya to 135yd, and 143a to 143e on the incident surface 110a of the diffraction grating 110 are indicated by black circles, and the positions of incident light related to the respective measurement points are indicated by white circles. .

Referring to FIG. 17, the incident surface 110 a of the diffraction grating 110 is virtually divided into a lid shape according to the module dimension L. The four measurement points 135xa to 135xd; 135ya to 135yd corresponding to the four measurement lights 151x to 154x and 151y to 154y are located at the four corners of a square having a side of 4 × L. The measurement point 143b corresponding to the measurement light 162 is located at the center of the square defined by the four measurement points 135xa to 135xd; 135ya to 135yd. The measurement points 143a and 143c corresponding to the measurement beams 161 and 163 are separated from the measurement point 143b corresponding to the measurement beam 162 by a distance of 3 × L in the X direction. The measurement points 143d and 143e corresponding to the measurement lights 164 and 165 are separated from the measurement point 143b corresponding to the measurement light 162 by a distance of 3 × L in the Y direction.

The positions of light incident on the incident surface 110a of the diffraction grating 110 in relation to the measurement points 135xa to 135xd corresponding to the measurement lights 151x to 154x are four positions arranged in the X direction across the measurement points 135xa to 135xd. . The positions of the light incident on the incident surface 110a of the diffraction grating 110 in relation to the measurement points 135ya to 135yd corresponding to the measurement lights 151y to 154y are the positions of the four corners of a rectangle elongated in the Y direction with the measurement points 135ya to 135yd as the center. It is. The positions of light incident on the incident surface 110a of the diffraction grating 110 in relation to the measurement points 143a to 143e corresponding to the measurement lights 161 to 165 are two positions arranged in the X direction with the measurement points 143a to 143e interposed therebetween. .

With respect to each of the measurement lights 151x to 154x, the s-polarized measurement light reflected in the X direction by the polarization separation surface after reciprocating the optical path between the diffraction grating 110 and the reflection surface 137 as a reference surface of the reference member RM, The p-polarized reference light that has passed through the optical path between the two and transmitted through the polarization separation surface is emitted from the polarization beam splitter PBS along the same path. Thus, the interference lights 151xa and 151xb between the measurement light and the reference light corresponding to the measurement light 151x are emitted from the polarization beam splitter PBS along the same path and enter the input / output unit 111A. Similarly, interference light 152xa, 152xb; 153xa, 153xb; 154xa, 154xb between the measurement light and the reference light corresponding to the measurement lights 152x to 154x are emitted from the polarization beam splitter PBS along the same path, and input / output unit Incident on 111A.

Further, for each of the measurement lights 151y to 154y, the s-polarized measurement light reflected in the X direction by the polarization separation surface after two reciprocations of the optical path between the diffraction grating 110 and the reflection surface as the reference surface of the reference member RM The p-polarized reference light that has passed through the polarization separation surface after two reciprocations in the optical path to 137 is emitted from the polarization beam splitter PBS along the same path. Thus, the interference lights 151ya and 151yb of the measurement light and the reference light corresponding to the measurement light 151y are emitted from the polarization beam splitter PBS along the same path and enter the input / output unit 111A. Similarly, interference lights 152ya, 152yb; 153ya, 153yb; 154ya, 154yb between the measurement light and the reference light corresponding to the measurement lights 152y to 154y are emitted from the polarization beam splitter PBS along the same path, and are input / output units. Incident on 111A.

The input / output unit 111A supplies a detection signal obtained by photoelectrically detecting each interference light to the processing unit 115. The processing unit 115 performs measurement corresponding to the measurement light 151x on the diffraction grating 110 based on a difference between a detection signal obtained by photoelectric detection of the interference light 151xa and a detection signal obtained by photoelectric detection of the interference light 151xb. The X direction position of the point 135xa is obtained. Further, the processing unit 115 corresponds to the measurement light 151y on the diffraction grating 110 based on a difference between a detection signal obtained by photoelectric detection of the interference light 151ya and a detection signal obtained by photoelectric detection of the interference light 151yb. The Y direction position of the measurement point 135ya to be obtained is obtained.

Similarly, the processing unit 115 generates a signal on the diffraction grating 110 based on a difference between a detection signal obtained by photoelectric detection of the interference lights 152xa to 154xa and a detection signal obtained by photoelectric detection of the interference lights 152xb to 154xb. The X direction positions of the measurement points 135xb to 135xd corresponding to the measurement lights 152x to 154x are obtained. Further, the processing unit 115 performs measurement on the diffraction grating 110 based on a difference between a detection signal obtained by photoelectric detection of the interference lights 152ya to 154ya and a detection signal obtained by photoelectric detection of the interference lights 152yb to 154yb. The Y direction positions of the measurement points 135yb to 135yd corresponding to the lights 152y to 154y are obtained. The measurement results of the X measurement positions of the four measurement points 135xa to 135xd and the Y measurement positions of the four measurement points 135ya to 135yd obtained on the diffraction grating 110 obtained by the processing unit 115, and thus the four measurement points 135xa to 135xa of the wafer stage WS. 135xd: The measurement results of the X direction position and the Y direction position in 135ya to 135yd are supplied to the control system CR.

Further, for each of the measurement beams 161 to 165, the s-polarized measurement beam reflected in the X direction by the polarization separation surface of the polarization beam splitter PBS after reciprocating the optical path between the diffraction grating 110 and the reference member RM is referred to. The p-polarized reference light that has passed through the polarization separation surface after reciprocating twice along the optical path between the reflection surface 137 as a surface is emitted from the polarization beam splitter PBS along the same path. In this way, the interference lights 161a, 162a, 163a, 164a, 165a of the measurement light corresponding to the measurement lights 161 to 165 and the reference light are emitted from the polarization beam splitter PBS along the same path and incident on the input / output unit 111A. To do.

The input / output unit 111A supplies a detection signal obtained by photoelectrically detecting the interference lights 161a to 165a to the processing unit 115. Based on the detection signal obtained by photoelectrically detecting the interference lights 161a to 165a, the processing unit 115 determines the positions in the Z direction of the five measurement points 143a to 143e corresponding to the measurement lights 161 to 165 on the diffraction grating 110, respectively. Ask. The measurement results of the Z direction positions of the five measurement points 143a to 143e on the diffraction grating 110 obtained by the processing unit 115, and consequently the measurement results of the Z direction positions of the five measurement points 143a to 143e of the wafer stage WS, are controlled by the control system. Supplied to CR.

Note that the wafer stage WS holding the wafer W is stepped over a predetermined range along the XY plane during exposure. In the second embodiment, the four measurement units 111 and the pair of reflective diffraction gratings 110 always measure the position of the wafer stage WS by the cooperative action of at least one measurement unit 111 and the diffraction grating 110 facing the measurement unit 111. Arranged to be able to do. In general, various forms are possible for the number and arrangement of measurement units, the number and arrangement of diffraction gratings, and the like.

As described above, the position measuring apparatus 1A according to the second embodiment measures the relative position of the wafer stage (second member) WS whose relative position with respect to the exposure apparatus main body (first member) is variable. Specifically, the position measuring apparatus 1A has a polarization beam splitter PBS and a reference member RM fixedly attached to the exposure apparatus main body, and a two-dimensional periodic structure attached to the wafer stage WS along the X direction and the Y direction. And a reflective diffraction grating 110.

In the position measuring apparatus 1A, using a single polarization beam splitter PBS fixedly attached to the exposure apparatus main body, the X measurement position and the Y direction position at the four measurement points 135xa to 135xd; 135ya to 135yd of the wafer stage WS. And the Z-direction positions at the five measurement points 143a to 143e of the wafer stage WS are simultaneously measured by a so-called heterodyne interference method. As a result, in addition to the X-direction position, the Y-direction position, and the Z-direction position at a plurality of points on the wafer stage WS, the rotation position of the wafer stage WS around the X-axis, the rotation position around the Y-axis, and the Z-axis position The position of rotation is also measured at the same time.

Further, in the position measuring apparatus 1A, measurement is a first-order diffracted light generated in an oblique direction from the diffraction grating 110 along the same optical path as the incident light path to the diffraction grating 110 in accordance with light obliquely incident at the Littrow angle of the diffraction grating 110. Based on the interference between the light and the corresponding reference light, the X-direction position and the Y-direction position of the diffraction grating 110 (and thus the wafer stage WS) are measured. At this time, the incident light to the diffraction grating 110 and the measurement light emitted from the diffraction grating 110 reciprocate in the same region of the deflecting

members

134a and 134b attached to the polarization beam splitter PBS via the quarter wavelength plate 133. . As a result, the optical path of the measurement light between the polarization beam splitter PBS (and thus the measurement unit 111) and the diffraction grating 110 can be shortened.

As described above, in the position measurement apparatus 1A according to the second embodiment, since the optical path length of the measurement light between the measurement unit 111 and the diffraction grating 110 can be reduced, the measurement error due to the atmospheric fluctuation is reduced. Thus, the position measurement of the wafer stage WS can be stably and highly accurately performed. Therefore, in the exposure apparatus of the second embodiment, the position measurement apparatus 1 that stably and highly accurately measures the position of the wafer stage WS while suppressing the measurement error caused by the atmospheric fluctuation is used in the projection optical system PL. On the other hand, the wafer W on the wafer stage WS can be aligned with high accuracy, and hence good projection exposure can be performed.

In the second embodiment, since a single polarization beam splitter PBS fixedly attached to the exposure apparatus main body is used, the wafer stage WS along the X direction and the Y direction, which are in-plane directions of the wafer W, is used. And the position measurement of the wafer stage WS along the Z direction, which is the normal direction of the wafer W, can be performed simultaneously and stably.

By the way, in the second embodiment, when measuring the position in the X direction and the Y direction of the diffraction grating 110, an error in the flatness of the surface of the light transmission portion provided so as to cover the diffraction pattern in the diffraction grating 110 is mixed in the detection signal. As a result, a measurement error due to a so-called flatness error may occur. The flatness error is obtained by using a difference signal between a measurement signal from the first measurement unit that measures the X-direction position of the diffraction grating 110 and a measurement signal from the second measurement unit that measures the Y-direction position of the diffraction grating 110. Cannot be canceled.

Therefore, in the second embodiment, the measurement result of the third measurement unit that measures the Z-direction position of the diffraction grating 110, that is, the measurement result regarding the distribution of the Z-direction position of the diffraction grating 110 is used to reduce the flatness error. The measurement error caused by the first measurement unit and the second measurement unit is corrected. At this time, the interval between the measurement points of the plurality of third measurement units (measurement axis interval) is set to the interval between the measurement points of the plurality of first measurement units (measurement axis interval) and the measurement point of the plurality of second measurement units. The measurement error by the first measurement unit and the second measurement unit can be corrected by setting the interval to the interval (measurement axis interval) or less.

Specifically, in the second embodiment, as shown in FIG. 17, the interval between the four X direction measurement points 135xa to 135xd is (4 × L), and the interval between the four Y direction measurement points 135ya to 135yd is shown. (4 × L), and the interval between the five Z-direction measurement points 143a to 143e is (3 × L). That is, the interval (3 × L) between the five Z direction measurement points is set to be less than or equal to the interval between the four X direction measurement points (4 × L) and the interval between the four Y direction measurement points (4 × L). Has been. Therefore, in the second embodiment, it is possible to correct the measurement error due to the flatness error when measuring the position in the X direction and the Y direction of the diffraction grating 110.

However, with respect to the number and position of the X direction measurement points, the number and position of the Y direction measurement points, the number and position of the Z direction measurement points, various forms that satisfy the above-described interval between the measurement points are possible. . As an example, as shown in FIG. 18, a configuration is possible in which the intervals between the eight Z-direction measurement points 143 are set to (2 × L) and arranged in a cross shape. In the example shown in FIG. 18, the numbers and positions of the X direction measurement points 35x and the Y direction measurement points 135y are the same as the example shown in FIG. Accordingly, also in the modified example of FIG. 18, the interval between the eight Z-direction measurement points (2 × L) is the interval between the four X-direction measurement points (4 × L) and the interval between the four Y-direction measurement points. It is set to (4 × L) or less.

If the flatness error of the light transmitting portion provided on the diffraction grating 110 can be removed from the measurement results obtained by the first measurement unit and the second measurement unit, for example, one interference light (corresponding to the measurement light 131). The output signal of the interference light obtained in this way and the output signal of the other interference light (interference light obtained corresponding to the measurement light 132) are handled independently, so that the correction pitch in the X direction is substantially halved. The correction error in the X direction can also be suppressed. Naturally, for example, the output signal of one interference light (interference light obtained corresponding to the measurement light 131y) and the output signal of the other interference light (interference light obtained corresponding to the measurement light 132y) are handled independently. As a result, the correction pitch in the Y direction can be substantially halved, and correction errors in the Y direction can be suppressed.

In the second embodiment described above, the deflecting

members

134a and 134b that deflect light passing through the polarizing beam splitter PBS and obliquely enter a predetermined region on the diffraction grating 110 at the Littrow angle of the diffraction grating 110 along a predetermined direction. In this example, a diffraction grating having a diffraction pattern having a periodic structure is used. However, the present invention is not limited to this, and various forms are possible for the specific configuration of the deflecting member. As an example, a deflecting member 181 having a diffractive action and a prism action can be used as shown in FIG. In the deflecting member 181 according to the modification of FIG. 19, a diffraction grating having a periodic diffraction pattern is formed on a wedge-shaped light transmitting member as a whole. The deflecting member 181 is attached to a required position on the quarter-wave plate 133 attached to the optical surface PBSa of the polarization beam splitter PBS. Further, a deflecting member having only a prism action may be used. In this case, the deflecting member 181 is removed from the diffraction grating having a periodic diffraction pattern, that is, a wedge-shaped light transmitting member as a whole.

Further, the measurement light incident on the region 135a (135c) and the measurement light incident on the region 135b (135d) may be slightly shifted from the relationship of being parallel to each other. With this configuration, it is possible to further improve the accuracy by removing the elliptically polarized light component that may occur during diffraction by the diffraction grating 110. In this case, when the diffraction grating 134a (134b) is used as the deflecting member, the diffraction grating includes a portion through which the measurement light incident on the region 135a (135c) passes and a portion through which the measurement light incident on the region 135b (135d) passes. You can change the pitch. When a wedge-shaped light transmitting member having a prism action is used as the deflecting member, a portion through which the measurement light incident on the region 135a (135c) passes, and a portion through which the measurement light incident on the region 135b (135d) passes. You just need to make the wedge angle different.

In the second embodiment described above, the position measuring apparatus of the present invention is applied to the position measurement of the wafer stage WS that moves while holding the wafer W in the exposure apparatus. However, the present invention is not limited to a wafer stage (substrate stage), and in general, the position measuring apparatus of the present invention can be similarly applied to position measurement of a stage that holds and moves an object. As an example, for example, as shown in FIG. 20, the position measurement apparatus of the present invention is applied to position measurement of a mask stage MS that holds and moves a mask M provided with a pattern to be transferred in the second embodiment. You can also

In the step-and-scan method, the mask stage MS holding the mask M moves along the Y direction that is the scanning direction. A position measuring apparatus 1A according to the modification of FIG. 20 includes a pair of reflective diffraction gratings 110 that are installed with a gap in the X direction with a mask M interposed therebetween, and a mask M (and thus a projection optical system PL). And a pair of measuring units 111 that are spaced apart in the X direction. FIG. 20 shows a reference state in which the center PAa of the pattern area PA of the mask M and the optical axis AX of the projection optical system PL are at the same position on the XY plane.

The diffraction grating 110 has, for example, an elongated rectangular outer shape along the Y direction, and is fixedly (or detachably) attached to the mask stage MS. The pair of measurement units 111 is fixedly attached to the exposure apparatus main body isolated from the mask stage MS. As an example, the pair of diffraction gratings 110 are arranged symmetrically with respect to an axis extending in the Y direction through the center PAa of the pattern area PA of the mask M, and have the same configuration. The pair of measurement units 111 are arranged symmetrically with respect to the axis extending in the Y direction through the optical axis AX so as to extend along the axis extending in the X direction through the optical axis AX of the projection optical system PL, and have the same configuration. Have

In the second embodiment described above, the polarization beam splitter PBS is attached to the exposure apparatus main body, the diffraction grating 110 is attached to the wafer stage WS, and the relative position of the wafer stage WS with respect to the exposure apparatus main body is variable. Measuring. However, the present invention is not limited thereto, and in general, in order to measure the relative position of the second member whose relative position with respect to the first member is variable, a polarization beam splitter fixedly attached to the first member, A diffraction grating attached to two members can be used. For example, in the second embodiment described above, the polarization beam splitter PBS is attached to the wafer stage WS, the diffraction grating 110 is attached to the exposure apparatus body, and the relative position of the wafer stage WS that is variable relative to the exposure apparatus body is measured. You can also In addition, when the position measurement apparatus of the present invention is applied to the position measurement of a stage that moves while holding an object, one of the polarization beam splitter and the diffraction grating is attached to the stage. Further, the diffraction grating 110 may be provided on the back surface of the wafer stage WS, and the polarization beam splitter PBS may be disposed on the surface plate side from the wafer stage.

Further, in the above-described second embodiment, the exposure apparatus is based on the interference light between the measurement light that has reciprocated twice along the optical path between the diffraction grating 110 and the reference light that has reciprocated twice along the optical path between the reference member RM. The relative position of the wafer stage WS whose relative position with respect to the main body is variable is measured. Thereby, for example, even if the wafer stage WS is tilted around the X axis or the Y axis, the relative position can be measured with high accuracy. However, the measurement target member is not limited to this, for example, based on the interference light between the measurement light that reciprocates once in the optical path between the diffraction grating and the reference light that reciprocates once in the optical path between the reference member. The relative position of can also be measured.

In the above-described embodiment, the holding member that holds the polarization beam splitter PBS may be made of a non-magnetic material. In this case, when the stage is driven by a linear motor, a planar motor, or the like, measurement errors caused by stress applied to the polarization beam splitter due to the influence of magnetic flux from the motor can be reduced.

In the above-described embodiment, a light transmission mask (reticle) in which a predetermined light-shielding pattern (or phase pattern / dimming pattern) is formed on a light-transmitting substrate is used. Instead of this reticle, For example, as disclosed in US Pat. No. 6,778,257, an electronic mask (variable shaping mask, which forms a transmission pattern, a reflection pattern, or a light emission pattern based on electronic data of a pattern to be exposed, as disclosed in US Pat. No. 6,778,257. Also called an active mask or an image generator, for example, a DMD (Digital Micro-mirror Device) which is a kind of non-light emitting image display element (spatial light modulator) may be used. When such a variable molding mask is used, a stage on which a workpiece such as a wafer or glass plate is mounted is scanned with respect to the variable molding mask, and the position of the workpiece is measured using a position detection system. Thus, an effect equivalent to that of the above embodiment can be obtained.

Further, as disclosed in, for example, International Publication No. 2001/035168, an exposure apparatus (lithography system) that forms a line-and-space pattern on a wafer W by forming interference fringes on the wafer W. The above embodiment can also be applied.
Furthermore, as disclosed in, for example, US Pat. No. 6,611,316, two reticle patterns are synthesized on a wafer via a projection optical system, and 1 on the wafer by one scanning exposure. The above embodiment can also be applied to an exposure apparatus that performs double exposure of two shot areas almost simultaneously.

In the above embodiment, the object on which the pattern is to be formed (the object to be exposed to which the energy beam is irradiated) is not limited to the wafer, but may be another object such as a glass plate, a ceramic substrate, a film member, or a mask blank. good.

The use of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, but for example, an exposure apparatus for liquid crystal that transfers a liquid crystal display element pattern to a square glass plate, an organic EL, a thin film magnetic head, an image sensor It can be widely applied to exposure apparatuses for manufacturing (CCD, etc.), micromachines, DNA chips, and the like. Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., glass substrates, silicon wafers, etc. The above embodiment can also be applied to an exposure apparatus that transfers a circuit pattern.

In the above embodiment, a step-and-scan type projection exposure apparatus is described as an example, but the present invention is also applied to a position measurement apparatus of a step-and-repeat type projection exposure apparatus. can do.

The exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus may be manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

Next, a device manufacturing method using the exposure apparatus according to the above-described embodiment will be described. FIG. 21 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 21, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a semiconductor device substrate (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the projection exposure apparatus of the above-described embodiment, the pattern formed on the mask (reticle) M is transferred to each shot area on the wafer W (step S44: exposure process), and the wafer W after the transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred (step S46: development process).

Thereafter, using the resist pattern generated on the surface of the wafer W in step S46 as a mask, processing such as etching is performed on the surface of the wafer W (step S48: processing step). Here, the resist pattern is a photoresist layer in which unevenness having a shape corresponding to the pattern transferred by the projection exposure apparatus of the above-described embodiment is generated, and the recess penetrates the photoresist layer. It is. In step S48, the surface of the wafer W is processed through this resist pattern. The processing performed in step S48 includes, for example, at least one of etching of the surface of the wafer W or film formation of a metal film or the like. In step S44, the projection exposure apparatus of the above-described embodiment performs pattern transfer using the wafer W coated with the photoresist as a photosensitive substrate.

FIG. 22 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 22, in the liquid crystal device manufacturing process, a pattern forming process (step S50), a color filter forming process (step S52), a cell assembling process (step S54), and a module assembling process (step S56) are sequentially performed. In the pattern forming process of step S50, a predetermined pattern such as a circuit pattern and an electrode pattern is formed on the glass substrate coated with a photoresist as the plate P using the projection exposure apparatus of the above-described embodiment. The pattern forming step includes an exposure step of transferring the pattern to the photoresist layer using the projection exposure apparatus of the above-described embodiment, and development of the plate P on which the pattern is transferred, that is, development of the photoresist layer on the glass substrate. And a developing step for generating a photoresist layer having a shape corresponding to the pattern, and a processing step for processing the surface of the glass substrate through the developed photoresist layer.

In the color filter forming process in step S52, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning direction. In the cell assembly process in step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembling process in step S56, various components such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD, etc.), micromachine, thin film magnetic head, and DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

The present invention can also be applied to a position measuring apparatus of an immersion type exposure apparatus disclosed in, for example, US Patent Publication No. 2011/0096315.
Further, the illumination optical system IL is not limited to ArF excimer laser light (wavelength 193 nm). For example, as disclosed in US Pat. No. 7,023,610, a DFB semiconductor laser or fiber laser is used as vacuum ultraviolet light. A single wavelength laser beam in the infrared or visible range oscillated from is amplified with, for example, a fiber amplifier doped with erbium (or both erbium and ytterbium), and converted into ultraviolet light using a nonlinear optical crystal. Harmonics may be used.

The above-described embodiment can also be applied to an exposure apparatus that uses a charged particle beam such as an electron beam or an ion beam.
It should be noted that all publications relating to the exposure apparatus and the like cited in the above description, international publication, US patent application specification and US patent specification disclosure are incorporated herein by reference.

1, 1A

Position measuring device

10, 110

Diffraction grating

11, 111

Measuring unit

11A, 111A Input /

output unit

12, 112 Measuring

light source

13, 113

Branch unit

14, 114

Light guide

15, 115 Processing section PBS Polarizing beam splitter RM Reference member LS exposure light source IL illumination optical system M mask MS mask stage PL projection optical system W wafer WS wafer stage DRw wafer stage drive system CR control system

Claims

In the position measuring device that measures the relative position of the second member whose relative position with respect to the first member is variable,
A polarizing beam splitter fixedly attached to the first member;
A reflective diffraction grating attached to the second member and having a periodic structure along a first direction;
A first measurement light which is a diffracted light along the first direction generated from the diffraction grating in response to the first polarized light incident on the diffraction grating via a first path in the polarization beam splitter; A first measurement unit that measures a relative position of the second member along the first direction based on interference with the second polarized first reference light corresponding to one measurement light;
A second measurement light that is zero-order light generated along the second direction from the diffraction grating in response to the light incident on the diffraction grating via the second path in the polarization beam splitter; and the second measurement light A position measurement device comprising: a second measurement unit that measures a relative position of the second member along the second direction based on interference with the corresponding second reference light.
The reference member according to claim 1, further comprising a reference member fixedly attached to the first member and having a diffraction surface that diffracts the first reference light and a reflection surface that reflects the second reference light. Position measuring device.
The first measurement unit includes a first deflection member that deflects + 1st-order diffracted measurement light, which is + 1st-order diffracted light among the first measurement light generated from the diffraction grating, and guides it to the polarization beam splitter; and the diffraction grating A second deflecting member that deflects the -1st order diffracted measurement light, which is the -1st order diffracted light of the first measured light generated from the first measured light, and guides it to the polarization beam splitter. Based on the interference with the + 1st order diffracted reference light corresponding to the + 1st order diffracted measuring light and the interference between the -1st order diffracted measuring light and the −1st order diffracted measured light corresponding to the −1st order diffracted measuring light, The position measuring device according to claim 1, wherein a relative position of the two members along the first direction is measured.
The first measurement unit includes a first folding member that translates the light that has passed through the first deflection member and the polarization beam splitter and returns the light to the polarization beam splitter, and light that has passed through the second deflection member and the polarization beam splitter. A second folding member that translates and returns the polarization beam splitter to the polarizing beam splitter, and deflects the + 1st-order diffraction measurement light generated from the diffraction grating in response to the incident light through the first folding member and the polarizing beam splitter. The polarization beam splitter deflects −1st-order diffraction measurement light generated from the diffraction grating in response to incidence of light that has passed through the third deflection member that guides to the polarization beam splitter, the second folding member, and the polarization beam splitter. The position measuring device according to claim 3, further comprising a fourth deflecting member that leads to the position.
A first diffractive surface that is fixedly attached to the first member and diffracts the light that has passed through the polarizing beam splitter; and a second diffractive surface that diffracts the light that has passed through the first folding member and the polarizing beam splitter. The position measuring device according to claim 4, further comprising a reference member having the reference member.
The position measuring apparatus according to claim 5, wherein the first diffraction surface has a diffraction pattern having a two-dimensional periodic structure, and the second diffraction surface has a diffraction pattern having a one-dimensional periodic structure.
The position measuring apparatus according to claim 4, wherein the first deflection member to the fourth deflection member have a diffraction pattern having a periodic structure along the first direction.
The position measurement apparatus according to claim 7, wherein the diffraction patterns of the first deflection member to the fourth deflection member are formed on an optical surface facing the diffraction grating of the polarization beam splitter.
The position measuring device according to claim 4, wherein the first folding member and the second folding member are fixedly attached to the polarization beam splitter.
The second measurement unit converts the first polarized light that has passed through the polarization beam splitter into circularly polarized light, guides it to the diffraction grating, and changes the second measurement light generated from the diffraction grating to the second polarized light. And a first polarizing member that guides to the polarizing beam splitter, and along the second direction of the second member based on interference between the second measurement light of the second polarization and the second reference light. The position measuring apparatus according to claim 1, wherein the relative position is measured.
The second measurement unit includes a third folding member that translates the light that has passed through the first polarizing member and the polarizing beam splitter and returns the light to the polarizing beam splitter, and the third folding member and the polarizing beam splitter that pass through the third measuring member. A second polarizing member that converts the second polarized light into circularly polarized light and guides it to the diffraction grating, and converts the second measurement light generated from the diffraction grating into the first polarized light and guides it to the polarizing beam splitter; The position measuring device according to claim 10, further comprising:
The position measuring apparatus according to claim 11, wherein the first polarizing member and the second polarizing member have a wave plate fixedly attached to the polarizing beam splitter.
The position measuring device according to claim 11 or 12, wherein the third folding member is fixedly attached to the polarization beam splitter.
A reference member fixedly attached to the first member;
The position measuring device according to claim 10, wherein a reflection surface is provided in an optical path of the second reference light in the reference member.
The diffraction grating has a two-dimensional periodic structure along the first direction and the third direction,
A third measurement light which is a diffracted light along the third direction generated from the diffraction grating in response to the light of the first polarization incident on the diffraction grating via a third path in the polarization beam splitter; A third measuring unit configured to measure a relative position of the second member along the third direction based on interference with the third reference light of the second polarized light corresponding to the third measuring light; The position measuring device according to claim 1, wherein:
The third measurement unit includes a fifth deflecting member that deflects the second + 1st order diffracted measurement light, which is the + 1st order diffracted light of the third measurement light generated from the diffraction grating, and guides it to the polarization beam splitter; A sixth deflecting member that deflects second-first-order diffracted measurement light, which is -1st-order diffracted light of the third measurement light generated from the diffraction grating, and guides it to the polarization beam splitter; Interference between the second + 1st order diffracted measurement light and the second + 1st order diffracted reference light corresponding to the second + 1st order diffracted measurement light, and the second -1st order diffracted measurement light and the second -1st order The relative position along the third direction of the second member is measured based on interference with the second-first order diffraction reference light corresponding to the folding measurement light. Position measuring device.
The third measurement unit includes a fourth folding member that translates the light that has passed through the fifth deflection member and the polarization beam splitter and returns the light to the polarization beam splitter, and the light that has passed through the sixth deflection member and the polarization beam splitter. A fifth folding member that translates the light into the polarization beam splitter, and the second + 1st-order diffraction measurement light generated from the diffraction grating in response to the incidence of light that has passed through the fourth folding member and the polarization beam splitter. And the second −1st-order diffracted measurement light generated from the diffraction grating in response to incidence of light that has passed through the fifth folding member and the polarization beam splitter. And an eighth deflecting member that deflects the light to the polarizing beam splitter. Position measuring device.
The position measurement apparatus according to claim 17, wherein each of the fifth to eighth deflection members has a diffraction pattern having a periodic structure along the third direction.
19. The position measuring apparatus according to claim 18, wherein the diffraction patterns of the fifth deflection member to the eighth deflection member are formed on an optical surface facing the diffraction grating of the polarization beam splitter.
The position measuring device according to claim 17, wherein the fourth folding member and the fifth folding member are fixedly attached to the polarization beam splitter.
The first route and the third route are common routes,
The first folded member and the fourth folded member have a common corner cube,
21. The position measuring device according to claim 17, wherein the second folded member and the fifth folded member have a common corner cube.
The position measurement apparatus according to any one of claims 15 to 21, wherein the first direction, the second direction, and the third direction are orthogonal to each other.
A reference fixedly attached to the first member and having a diffractive surface that diffracts the second reference light to generate the second + 1st order diffracted measurement light and the second -1st order diffracted measurement light. The position measuring device according to any one of claims 15 to 22, further comprising a member.
A reference member fixedly attached to the first member;
In the reference surface of the reference member, a diffraction pattern having a periodic structure is provided in each of the reflection regions of the first reference light and the third reference light, and a planar reflection surface is provided in the reflection region of the second reference light. The position measuring device according to claim 15, wherein the position measuring device is provided.
2. The first polarized light is one of s-polarized light and p-polarized light with respect to a polarization separation surface of the polarizing beam splitter, and the second polarized light is the other of s-polarized light and p-polarized light. 25. The position measuring device according to any one of items 24 to 24.
26. The position measuring apparatus according to claim 1, wherein the first path and the second path in the polarization beam splitter are different paths.
The second member is provided with a reflective diffraction grating having a variable relative position to the first member and having a periodic structure along the first direction.
The first measurement unit passes through the polarization beam splitter, and passes from the diffraction grating in the first plane according to light obliquely incident on the diffraction grating along a predetermined path in the first plane including the first direction. Based on the interference light between the first measurement light, which is diffracted light generated along the predetermined path, and the first reference light corresponding to the first measurement light, the second member along the first direction. A first deflection that measures a relative position and deflects light passing through the polarization beam splitter and obliquely enters the first region on the diffraction grating along a first path at a Littrow angle of the reflective diffraction grating. 27. The position measuring apparatus according to claim 1, further comprising a member.
In the position measurement device for measuring the relative position of the second member provided with a reflection type diffraction grating having a variable relative position with respect to the first member and having a periodic structure along the first direction,
A polarizing beam splitter fixedly attached to the first member;
Generated from the diffraction grating along the predetermined path in the first plane in response to light obliquely incident on the diffraction grating along a predetermined path in the first plane including the first direction via the polarizing beam splitter First relative position of the second member along the first direction is measured based on interference light between the first measurement light that is diffracted light and the first reference light corresponding to the first measurement light. With a measuring unit,
The first measurement unit deflects light that has passed through the polarization beam splitter, and obliquely enters the first region on the diffraction grating along the first path at a Littrow angle of the reflective diffraction grating. A position measuring device having a member.
29. The polarization beam splitter includes a main surface provided on a plane including the first direction, and the first deflection member is provided on the main surface. Position measuring device.
The first measurement unit includes a second deflecting member that deflects light that has passed through the polarization beam splitter and obliquely enters the second region on the diffraction grating along the second path at a Littrow angle of the diffraction grating. , Interference light of the first measurement light generated from the first region of the diffraction grating along the first path, and the first light generated from the second region of the diffraction grating along the second path. A relative position along the first direction of the second member at a first measurement position between the first region and the second region is measured based on interference light of measurement light. 30. The position measuring device according to any one of claims 27 to 29.
31. The position measuring apparatus according to claim 30, wherein the first deflection member and the second deflection member have a diffraction pattern having a periodic structure along the first direction.
The polarizing beam splitter includes a main surface provided on a plane including the first direction, and the first deflecting member and the second deflecting member are provided on the main surface. 31. The position measurement apparatus according to 31.
The first measurement unit includes a first folding member that translates the light that has passed through the first deflection member and the polarization beam splitter and returns the light to the polarization beam splitter, and light that has passed through the second deflection member and the polarization beam splitter. A second folding member that translates and returns the polarized beam splitter to the polarizing beam splitter, and deflects the light that has passed through the first folding member and the polarizing beam splitter to deflect the diffraction grating along a third path parallel to the first path. A third deflecting member that obliquely enters the third region above, the light that has passed through the second folding member and the polarization beam splitter, and deflects the light on the diffraction grating along a fourth path parallel to the second path. And a fourth deflecting member that obliquely enters the fourth region, wherein the first measurement position is located between the first region and the fourth region. Position measuring device according to any one of Motomeko 30 to 32.
34. The position measuring apparatus according to claim 33, wherein the third deflection member and the fourth deflection member have a diffraction pattern having a periodic structure along the first direction.
The said 1st deflection member and the said 3rd deflection member are integrally formed, The said 2nd deflection member and the said 4th deflection member are integrally formed, The Claim 33 or 34 characterized by the above-mentioned. Position measuring device.
The first measurement unit changes the first polarized light that has passed through the polarization beam splitter to circularly polarized light, guides it to the diffraction grating, and changes the first measurement light generated from the diffraction grating to second polarized light. 36. The position measuring apparatus according to claim 27, further comprising a first polarizing member that leads to the polarizing beam splitter.
37. The position measuring apparatus according to claim 36, wherein the first polarizing member has a wave plate attached between the first deflecting member and the polarizing beam splitter.
A first reference member fixedly attached to the first member;
38. The position measuring device according to claim 27, wherein a planar reflecting surface is provided in an optical path of the first reference light in the first reference member.
The diffraction grating has a two-dimensional periodic structure along the first direction and the second direction;
Generated from the diffraction grating along the predetermined path in the second plane in response to light obliquely incident on the diffraction grating along a predetermined path in the second plane including the second direction via the polarizing beam splitter A second position measuring the relative position of the second member in the second direction based on interference light between the second measurement light that is diffracted light and the second reference light corresponding to the second measurement light. The position measuring device according to any one of claims 27 to 38, further comprising a measuring unit.
The second measurement unit deflects the light that has passed through the polarization beam splitter and obliquely enters the fifth region on the diffraction grating along the fifth path at a Littrow angle of the diffraction grating; and A sixth deflecting member that deflects light that has passed through the polarization beam splitter and obliquely enters the sixth region on the diffraction grating along the sixth path at a Littrow angle of the diffraction grating, Interference light of the second measurement light generated from the fifth region along the fifth path and interference light of the second measurement light generated from the sixth region of the diffraction grating along the sixth path. 40. The position according to claim 39, wherein a relative position along the second direction of the second member at a second measurement position between the fifth area and the sixth area is measured based on the position. Measuring device.
41. The position measuring apparatus according to claim 40, wherein the fifth deflecting member and the sixth deflecting member have a diffraction pattern having a periodic structure along the second direction.
The second measurement unit includes a third folding member that translates the light that has passed through the fifth deflection member and the polarization beam splitter and returns the light to the polarization beam splitter, and the light that has passed through the sixth deflection member and the polarization beam splitter. A fourth folding member that translates and returns the polarized beam splitter to the polarization beam splitter, and deflects the light that has passed through the third folding member and the polarization beam splitter to deflect the diffraction grating along a seventh path parallel to the fifth path. A seventh deflecting member that is obliquely incident on the upper seventh region; and the light that has passed through the fourth folding member and the polarization beam splitter is deflected to travel on the diffraction grating along an eighth path parallel to the sixth path. An eighth deflecting member that obliquely enters the eighth region, and the second measurement position is located between the fifth region and the eighth region. Position measuring device according to claim 40 or 41.
43. The position measuring apparatus according to claim 42, wherein the seventh deflection member and the eighth deflection member have a diffraction pattern having a periodic structure along the second direction.
The said 5th deflection member and the said 7th deflection member are integrally formed, and the said 6th deflection member and the said 8th deflection member are integrally formed, 44 or 43 characterized by the above-mentioned. Position measuring device.
The second measuring unit changes the first polarized light that has passed through the polarization beam splitter to circularly polarized light, guides it to the diffraction grating, and changes the second measurement light generated from the diffraction grating to second polarized light. The position measuring device according to any one of claims 39 to 44, further comprising a second polarizing member that leads to the polarizing beam splitter.
46. The position measuring apparatus according to claim 45, wherein the second polarizing member includes a wave plate attached between the fifth deflecting member and the polarizing beam splitter.
The first folded member and the third folded member have a common corner cube,
47. The position measuring apparatus according to claim 33, wherein the second folded member and the fourth folded member have a common corner cube.
A second reference member fixedly attached to the first member;
48. The position measuring device according to claim 39, wherein a planar reflecting surface is provided in an optical path of the second reference light in the second reference member.
Third measurement light that is zero-order light generated along the third direction from the diffraction grating according to light incident on the diffraction grating via the polarization beam splitter, and a third reference corresponding to the third measurement light 49. The apparatus according to any one of claims 27 to 48, further comprising a third measurement unit that measures a relative position of the second member along the third direction based on interference light with light. The position measuring device described in 1.
The third measuring unit converts the first polarized light that has passed through the polarization beam splitter into circularly polarized light, guides it to a ninth region on the diffraction grating, and generates the first light generated from the ninth region on the diffraction grating. 50. The position measuring apparatus according to claim 49, further comprising a third polarizing member that changes the third measuring light into the second polarized light and guides the measured light to the polarizing beam splitter.
The third measuring unit translates the light passing through the third polarizing member and the polarizing beam splitter and returns the light to the polarizing beam splitter, and the third measuring unit passes through the fifth folding member and the polarizing beam splitter. The second polarized light is changed to circularly polarized light and led to the tenth region on the diffraction grating, and the third measurement light generated from the tenth region on the diffraction grating is changed to the first polarized light to change the first polarized light. 51. The position measuring apparatus according to claim 50, further comprising a fourth polarizing member that leads to the polarizing beam splitter.
52. The position measuring apparatus according to claim 51, wherein the third polarizing member and the fourth polarizing member have a wave plate attached to the polarizing beam splitter.
53. The position measurement apparatus according to claim 51, wherein the fifth folding member is attached to the polarization beam splitter.
A third reference member fixedly attached to the first member;
54. The position measuring apparatus according to claim 49, wherein a planar reflecting surface is provided in an optical path of the third reference light in the third reference member.
The first reference member to the third reference member have a common reflecting surface,
55. The position measurement apparatus according to claim 54, wherein the common reflection surface is provided so as to contact a wave plate attached to the polarization beam splitter.
A plurality of the first measurement units; and a plurality of the third measurement units.
The interval between the plurality of measurement positions on the diffraction grating by the plurality of third measurement units is equal to or less than the interval between the plurality of measurement positions on the diffraction grating by the plurality of first measurement units. The position measuring device according to any one of claims 49 to 55.
The diffraction grating has a two-dimensional periodic structure along the first direction and the second direction;
Generated from the diffraction grating along the predetermined path in the second plane in response to light obliquely incident on the diffraction grating along a predetermined path in the second plane including the second direction via the polarizing beam splitter Measuring a relative position of the second member in the second direction based on interference between the second measurement light that is diffracted light and the second reference light corresponding to the second measurement light. A second measuring unit;
The interval between the plurality of measurement positions on the diffraction grating by the plurality of third measurement units is equal to or less than the interval between the plurality of measurement positions on the diffraction grating by the plurality of second measurement units. 57. The position detection device according to claim 56.
The first polarized light is one of s-polarized light and p-polarized light with respect to a polarization separation surface of the polarization beam splitter, and the second polarized light is the other of s-polarized light and p-polarized light. 58. The position measuring device according to any one of 57 to 57.
In a stage apparatus comprising a stage that holds an object and a drive unit that moves the stage,
A position measuring device according to any one of claims 1 to 58 is provided,
One of the polarizing beam splitter and the diffraction grating is attached to the stage.
60. The stage device according to claim 59, comprising a plurality of the position measuring devices arranged in parallel.
In an exposure apparatus that exposes a predetermined pattern on a substrate,
61. An exposure apparatus comprising the stage apparatus according to claim 59, wherein the stage apparatus moves while holding the substrate.
62. One of the polarizing beam splitter and the diffraction grating is attached to the stage, and the other of the polarizing beam splitter and the diffraction grating is attached to an exposure apparatus main body. Exposure equipment.
Using the exposure apparatus according to claim 61 or 62, exposing the predetermined pattern onto the substrate;
Developing the substrate to which the predetermined pattern is transferred, and forming a mask layer having a shape corresponding to the predetermined pattern on the surface of the substrate;
Processing the surface of the substrate through the mask layer. A device manufacturing method comprising: