HK1136879A - Movable body apparatus - Google Patents

Description

Moving body device

Technical Field

The present invention relates to a movable body apparatus, a pattern forming apparatus, an exposure apparatus, and a device manufacturing method, and more particularly, to a movable body apparatus including a movable body that moves substantially along a predetermined plane, a pattern forming apparatus that forms a pattern on an object mounted on the movable body, an exposure apparatus that forms a pattern on the object by irradiating an energy beam, and a device manufacturing method using the exposure apparatus.

Background

Conventionally, in a lithography process for manufacturing electronic devices (microdevices) such as semiconductor devices and liquid crystal display devices, a projection exposure apparatus of a step-and-repeat system (so-called stepper), a projection exposure apparatus of a step-and-scan system (so-called scanning stepper (also called scanner)), and the like have been mainly used.

In such a projection exposure apparatus, the position of a stage holding a substrate to be exposed, for example, a wafer, is generally measured using a laser interferometer. However, as the required performance becomes more stringent with the miniaturization of the pattern due to the high integration of the semiconductor device, for example, in terms of the overlay error, the allowable value of the global overlay error is on the order of several nm, and the allowable value of the position control error of the stage is also on the order of sub-millimeter or less.

Therefore, recently, an encoder having a high analysis capability, which is less susceptible to air shake than an interferometer, has been attracting attention, and an invention related to an exposure apparatus using the encoder for position measurement of a wafer stage or the like has been proposed (see, for example, wo 2007/097379 pamphlet).

The exposure apparatus and the like disclosed in the above-mentioned wo 2007/097379 pamphlet use a plurality of encoder heads to measure the position of a wafer stage and the like. However, when the position of the wafer stage or the like is measured using a plurality of encoder heads, there is a possibility that an abnormality occurs in the output of each encoder head due to a malfunction of the encoder head, for example, a mechanical failure. On the other hand, in order to realize exposure with high accuracy even under the above-described circumstances, a system capable of continuously measuring the position of the wafer stage with high accuracy is required.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a first movable body apparatus including a movable body that substantially moves along a predetermined plane, comprising: a scale arranged on one of the movable body and an outer portion of the movable body, the scale having a grating section which has a first direction in a plane parallel to the predetermined plane as a longitudinal direction and has a predetermined width in a second direction orthogonal to the first direction; and a measuring device that measures positional information of the movable body in a periodic direction of the grating section at a plurality of measurement points arranged on the scale; the arrangement of the plurality of measurement points is set so that n points (where n is an integer of 2 or more) or more of the plurality of measurement points are within the predetermined width on the scale, and n +1 points or more of the plurality of measurement points are within the predetermined width on the scale when the movable body is at the predetermined position.

According to the above, n points (where n is an integer of 2 or more) or more among the plurality of measurement points included in the measurement device are located within the predetermined width on the scale, and when the movable body is located at the predetermined position, n +1 points or more are located within the predetermined width on the scale. Therefore, the positional information of the movable body in the periodic direction of the grating section of the scale can be measured at least at one measurement point. Therefore, even if a measurement error occurs in a part of the measurement points that are n +1 or more points within the predetermined width on the scale when the movable body is at the predetermined position, the positional information of the movable body in the periodic direction of the grating section of the scale can be reliably measured at the remaining measurement points.

According to a second aspect of the present invention, there is provided a second movable body apparatus including a movable body that substantially moves along a predetermined plane, comprising: a scale arranged on one of the movable body and an outer portion of the movable body, the scale having a grating section which has a first direction in a plane parallel to the predetermined plane as a longitudinal direction and has a predetermined width in a second direction orthogonal to the first direction; a measuring device that measures positional information of the movable body in a periodic direction of the grating section at a plurality of measuring points arranged on the scale; the measuring apparatus includes a plurality of head sets including a first head for irradiating a first measuring point with measuring light and a second head for irradiating the first measuring point or its vicinity with measuring light.

According to the above, the measuring apparatus includes a plurality of head groups including a first head for irradiating the measuring beam to a first measuring point among the plurality of measuring points and a second head for irradiating the measuring beam to the first measuring point or its vicinity. Therefore, even when an abnormality occurs in the measurement information of one of the first head and the second head included in the head group, the other head can be used, so that the head group can stably irradiate the scale with the measurement light and measure the position information of the movable body in the periodic direction of the grating portion of the scale. Therefore, by using a measuring apparatus having a plurality of head groups, it is possible to reliably measure the positional information of the moving body in the periodic direction of the grating section of the scale.

According to a third aspect of the present invention, there is provided a third movable body apparatus including a movable body substantially moving along a predetermined plane, the third movable body apparatus including a measurement device for measuring positional information of the movable body in a one-degree-of-freedom direction within the predetermined plane at a plurality of measurement points arranged within a movement range of the movable body; the measurement device includes a plurality of heads that generate measurement information by irradiating measurement light onto at least one of the plurality of measurement points when the movable body is located at the predetermined position.

According to the above, the measurement device includes a plurality of heads that generate measurement information by irradiating measurement light onto at least one of the plurality of measurement points when the movable body is at the predetermined position. Therefore, the position information of the one degree of freedom direction of the movable body in the predetermined plane can be measured using the at least one head. Therefore, even if some of the plurality of heads have different lengths, the positional information of the movable body in one degree of freedom direction in a predetermined plane can be reliably measured using the remaining other heads.

According to a fourth aspect of the present invention, there is provided a pattern forming apparatus for forming a pattern on an object, the apparatus comprising: a patterning device configured to form a pattern on the object; and a movable body apparatus (to be precise, any one of the first, second, and third movable body apparatuses) of the present invention that mounts the object on the movable body.

As described above, the patterning device can generate a pattern on the object on the movable body that constitutes a part of the movable body device of the present invention and can reliably measure the positional information in the measurement direction. Therefore, the pattern can be formed on the object with good accuracy.

According to a fifth aspect of the present invention, there is provided an exposure apparatus for forming a pattern on an object by irradiating an energy beam, comprising: a patterning device for irradiating the object with the energy beam; a movable body device of the present invention that mounts the object on the movable body; and a driving device for driving the movable body so as to move the object relative to the energy beam.

According to the above, the moving body on which the object is mounted is driven by the driving device with good accuracy in order to move the object with respect to the energy beam irradiated from the patterning device to the object. Therefore, a pattern can be formed on an object with good accuracy by scanning exposure.

According to a sixth aspect of the present invention, there is provided a device manufacturing method using the exposure apparatus of the present invention.

Drawings

FIG. 1 is a schematic configuration diagram showing an exposure apparatus according to an embodiment;

fig. 2(a) is a plan view showing a wafer stage;

fig. 2(B) is a plan view showing the measurement stage;

fig. 3 is a diagram illustrating the arrangement of the distance measuring axes of the interferometer system of the exposure apparatus of fig. 1, and is a plan view shown with a part of the stage apparatus omitted;

FIG. 4 is a view showing various measurement system configurations provided in the exposure apparatus of FIG. 1;

FIG. 5 is a diagram showing the configuration of an encoder readhead (X readhead, Y readhead) and an alignment system;

FIG. 6 is a diagram showing the configuration of the Z-read head and the multipoint AF system;

FIG. 7 is a block diagram showing the main configuration of a control system of the exposure apparatus of FIG. 1;

fig. 8(a) and 8(B) are diagrams for explaining position measurement in the XY plane of the wafer stage by the plurality of encoders and switching of the heads;

FIGS. 9A and 9B are diagrams illustrating a baseline measurement operation of the secondary alignment system performed at the beginning of a batch;

fig. 10(a) and 10(B) are diagrams for explaining first and second modifications of the encoder system, respectively;

fig. 11(a) and 11(B) are diagrams for explaining third and fourth modifications of the encoder system, respectively;

fig. 12 is a diagram for explaining another modification of the encoder system.

Detailed Description

An embodiment of the present invention will be described below with reference to fig. 1 to 9 (B).

Fig. 1 schematically shows the configuration of an exposure apparatus 100 according to an embodiment. The exposure apparatus 100 is a projection exposure apparatus of a step-and-scan method, i.e., a so-called scanner. As will be described later, in the present embodiment, the projection optical system PL is provided, and in the following description, a direction parallel to the optical axis AX of the projection optical system PL is referred to as a Z-axis direction, a direction in which the reticle and the wafer are relatively scanned in a plane orthogonal to the Z-axis direction is referred to as a Y-axis direction, a direction orthogonal to the Z-axis and the Y-axis is referred to as an X-axis direction, and directions of rotation (inclination) about the X-axis, the Y-axis, and the Z-axis are referred to as θ X, θ Y, and θ Z directions, respectively.

The exposure apparatus 100 includes: illumination system 10, reticle stage RST, projection unit PU, stage device 50 including wafer stage WST and measurement stage MST, and a control system for the above-described devices. The exposure apparatus 100 has a configuration which is partially different from that of an encoder system described later, but is generally the same as that of the exposure apparatus disclosed in the aforementioned pamphlet of international publication No. 2007/097379 (and corresponding U.S. patent application publication No. 2008/0088843). Therefore, the following description will simplify the components except for the special case. In fig. 1, wafer W is mounted on wafer stage WST.

The illumination system 10 includes a light source, an illumination uniformizing optical system including an optical integrator and the like, and an illumination optical system including a reticle blind and the like (both not shown), as disclosed in, for example, U.S. patent application publication No. 2003/0025890 and the like. The illumination system 10 illuminates a slit illumination area IAR on a reticle R defined by a reticle blind (mask system) with illumination light (exposure light) IL at a substantially uniform illuminance. Here, as the illumination light IL, an ArF excimer laser (wavelength 193nm) is used, for example.

A reticle R having a circuit pattern or the like formed on its pattern surface (the lower surface in fig. 1) is fixed to the reticle stage RTS by, for example, vacuum suction. Reticle stage RST can be driven slightly in the XY plane by reticle stage driving system 11 (not shown in fig. 1, see fig. 7) including, for example, a linear motor or the like, and can be driven in the scanning direction (the Y-axis direction in the left-right direction in the drawing plane of fig. 1) at a predetermined scanning speed.

Positional information (including rotation information in the θ z direction) of reticle stage RST in the XY plane (moving surface) is constantly detected by an analyzing capability of about 0.25nm, for example, by a reticle laser interferometer (hereinafter referred to as "reticle interferometer") 116 through moving mirror 15 (actually, a Y moving mirror (or retroreflector) having a reflecting surface orthogonal to the Y axis and an X moving mirror having a reflecting surface orthogonal to the X axis are provided). The measurement values of the reticle interferometer 116 are transmitted to the main controller 20 (not shown in fig. 1, see fig. 7).

Projection unit PU is disposed below reticle stage RST in fig. 1. The projection unit PU includes: the lens barrel 40 and the projection optical system PL have a plurality of optical elements held in a predetermined positional relationship in the lens barrel 40. As the projection optical system PL, for example, a refractive optical system composed of a plurality of lenses (lens elements) arranged along an optical axis AX parallel to the Z-axis direction is used. The projection optical system PL is, for example, telecentric on both sides and has a predetermined projection magnification (for example, 1/4 times, 1/5 times, 1/8 times, or the like). Thus, when illumination area IAR is illuminated with illumination light IL from illumination system 10, a reduced circuit pattern image (a reduced partial circuit pattern image) of reticle R in illumination area IAR is formed in area (hereinafter also referred to as exposure area) IA through projection optical system PL (projection unit PU) by illumination light IL of reticle R that is arranged so that the first surface (object surface) of projection optical system PL and the pattern surface thereof substantially coincide; the area IA is conjugate to the illumination area IAR disposed on the second surface (image surface) side of the wafer W, the surface of which is coated with a resist (photosensitive agent). Next, by synchronously driving reticle stage RST and wafer stage WST, the reticle is moved in the scanning direction (Y-axis direction) with respect to illumination area IAR (illumination light IL), and wafer W is moved in the scanning direction (Y-axis direction) with respect to exposure area IA (illumination light IL), whereby one irradiation area (divided area) on wafer W is scanned and exposed, and the pattern of the reticle is transferred to the irradiation area. That is, in the present embodiment, a pattern is generated on the wafer W by the illumination system 10, the reticle R, and the projection optical system PL, and the pattern is formed on the wafer W by exposing the photosensitive layer (resist layer) on the wafer W with the illumination light IL.

The exposure apparatus 100 of the present embodiment is provided with a local liquid immersion apparatus 8 for performing exposure by a liquid immersion method. The local immersion apparatus 8 includes a liquid supply apparatus 5, a liquid recovery apparatus 6 (both not shown in fig. 1 and see fig. 7), a liquid supply pipe 31A, a liquid recovery pipe 31B, a nozzle unit 32, and the like. As shown in fig. 1, the nozzle unit 32 is suspended and supported by a main frame, not shown, which holds the projection unit PU, so as to surround the periphery of the lower end portion of the lens barrel 40 which holds a lens (hereinafter, also referred to as a "tip lens") 191 constituting an optical element on the most image plane side (wafer W side) of the projection optical system PL. In the present embodiment, as shown in fig. 1, the lower end surface of the nozzle unit 32 is set to be substantially flush with the lower end surface of the distal end lens 191. The nozzle unit 32 includes a supply port and a recovery port for the liquid Lq, a lower surface disposed opposite to the wafer W and provided with a recovery port, and a supply flow path and a recovery flow path connected to the liquid supply tube 31A and the liquid recovery tube 31B, respectively. As shown in fig. 4, the liquid supply tube 31A and the liquid recovery tube 31B are inclined 45 ° in a plan view (viewed from above) with respect to the X-axis direction and the Y-axis direction, and are arranged symmetrically with respect to a straight line (reference axis) LV passing through the center of the projection unit PU (the optical axis AX of the projection optical system PL, and in the present embodiment, coinciding with the center of the exposure area IA) and parallel to the Y-axis direction.

The liquid supply pipe 31A is connected to the liquid supply device 5 (not shown in fig. 1, see fig. 7), and the liquid recovery pipe 31B is connected to the liquid recovery device 6 (not shown in fig. 1, see fig. 7). The liquid supply device 5 here includes a tank for storing liquid, a pressure pump, a temperature control device, a valve for controlling the flow rate of liquid, and the like. The liquid recovery device 6 includes a tank for storing the recovered liquid, a suction pump, a valve for controlling the flow rate of the liquid, and the like.

The main controller 20 controls the liquid supply device 5 (see fig. 7) to supply the liquid between the front lens 191 and the wafer W through the liquid supply tube 31A, and controls the liquid recovery device 6 (see fig. 7) to recover the liquid from between the front lens 191 and the wafer W through the liquid recovery tube 31B. At this time, the main controller 20 controls the liquid supply device 5 and the liquid recovery device 6 so that the amount of liquid supplied and the amount of water recovered are constantly equal to each other. Therefore, the liquid immersion area 14 is formed by holding a certain amount of liquid Lq (see fig. 1) while the front end lens 191 and the wafer W are replaced with each other (see, for example, fig. 8 a). When measurement stage MST described later is positioned below projection unit PU, liquid immersion area 14 can be formed between front end lens 191 and the measurement stage described later in the same manner.

In the present embodiment, pure water (hereinafter, simply referred to as water unless otherwise required) that allows ArF excimer laser light (light having a wavelength of 193nm) to transmit therethrough is used as the liquid. The refractive index n of water to ArF excimer laser light is approximately 1.44. In this water, the wavelength of the illumination light IL is shortened to about 134nm, i.e., 193nm × 1/n.

As shown in fig. 1, stage device 50 includes a wafer stage WST and a measurement stage MST disposed above base 12, a measurement system 200 (see fig. 7) for measuring positional information of these stages WST and MST, a stage drive system 124 (see fig. 7) for driving stages WST and MST, and the like. The measurement system 200 includes the interferometer system 118, the encoder system 150, and the surface position measurement system 180, as shown in fig. 7. The interferometer system 118, the encoder system 150, and the like are left to be described later.

Wafer stage WST and measurement stage MST are supported above base 12 by a plurality of non-contact bearings, not shown, fixed to the respective bottom surfaces, for example, air pads, through a gap of about several μm. Stages WST and MST can be independently driven in the XY plane by a stage driving system 124 (see fig. 7) including a linear motor and the like.

Wafer stage WST includes: a stage body 91; and a wafer table WTB mounted on stage body 91. Wafer table WTB and stage body 91 are driven in six-degree-of-freedom directions (X, Y, Z, θ X, θ Y, and θ Z) with respect to base 12 by a drive system including a linear motor and a Z leveling mechanism (including, for example, a voice coil motor).

A wafer holder (not shown) for holding the wafer W by vacuum suction or the like is provided at the center of the upper surface of the wafer table WTB. As shown in fig. 2a, a plate body (liquid-repellent plate) 28 is provided outside the wafer holder (wafer loading area), and the plate body 28 has a rectangular outer shape (contour) with a circular opening at the center thereof which is one turn larger than the wafer holder. The surface of the plate body 28 is treated (formed with a liquid repellent surface) to have a liquid repellent effect on the liquid Lq. Further, the plate 28 is disposed on the wafer table WTB so that the entire surface or a part of the surface is flush with the surface of the wafer W.

The plate body 28 has a rectangular first liquid repellent region 28a in which the outer shape (contour) of the circular opening is formed at the center, and a rectangular frame-shaped (annular) second liquid repellent region 28b disposed around the first liquid repellent region 28 a. Furthermore, the method is simple. In the present embodiment, since water is used as the liquid Lq as described above, the first and second liquid repellent sections 28a and 28b are hereinafter also referred to as first and second water repellent plates 28a and 28b, respectively.

A measurement plate 30 is provided at the + Y side end of the first water paddle 28 a. The measurement plate 30 has a reference mark FM at the center, and a pair of aerial image measurement slit patterns (slit-shaped measurement patterns) SL are provided so as to sandwich the reference mark FM. A light transmission system (not shown) for guiding illumination light IL transmitted through the aerial image measurement slit patterns SL to the outside of wafer stage WST (a light reception system provided on measurement stage MST described later) is provided corresponding to each aerial image measurement slit pattern SL.

A scale for an encoder system described later is formed on the second water paddle 28 b. Specifically, a Y scale 39Y is formed in each of the regions on one side and the other side (left and right sides in fig. 2 a) of the second water paddle 28b in the X axis direction₁，39Y₂. Y scale 39Y₁，39Y₂For example, a reflection type grating (for example, a diffraction grating) having a periodic direction in the Y-axis direction is formed in a direction (Y-axis direction) parallel to the Y-axis at a predetermined pitch by the grating lines 38 each having the X-axis direction as the longitudinal direction. Similarly, the areas on one side and the other side (upper and lower sides in fig. 2 a) of the second water-repellent plate 28b in the Y-axis direction are indicated by a Y scale 39Y₁And 39Y₂An X scale 39X is formed in a sandwiched state₁，39X₂. X Scale 39X₁，39X₂For example, a reflection type grating (for example, a diffraction grating) having a periodic direction in the X-axis direction is formed in a direction (X-axis direction) parallel to the X-axis at a predetermined pitch by the grating lines 37 each having the Y-axis direction as the longitudinal direction. The pitch of the grating lines 37, 38 is set to 1 μm, for example. In fig. 2(a), for convenience of illustration, the pitch of the grating is illustrated to be much larger than the actual pitch. This point is also the same in the other figures.

In addition, in order to protect the diffraction grating, it is also effective to cover the diffraction grating with a glass plate having a low thermal expansion coefficient with water repellency. Here, a glass plate having a thickness approximately equal to that of the wafer, for example, 1mm is used, and the glass plate surface and the wafer surface are set to the same height (surface position) on the upper surface of wafer stage WST.

the-Y end face and the-X end face of wafer table WTB are mirror-finished to form reflection surfaces 17a and 17b for interferometer system 118 shown in fig. 2(a) and described later, respectively.

As shown in fig. 1, measurement stage MST includes a stage main body 92 driven in the XY plane by a linear motor or the like, not shown, and a measurement table MTB mounted on stage main body 92. Measurement stage MST may be driven in at least three degrees of freedom (X, Y, θ z) relative to base 12 by a drive system, not shown.

In fig. 7, stage drive system 124 is shown including a drive system for wafer stage WST and a drive system for measurement stage MST.

Various measuring members are provided on measuring table MTB (and stage main body 92). As the measuring means, for example, as shown in fig. 2B, an illuminance unevenness sensor 94 having a pinhole-shaped light receiving section for receiving illumination light IL on an image plane of the projection optical system PL, an aerial image measuring instrument 96 for measuring a pattern aerial image (projection image) projected by the projection optical system PL, a Shack-Hartman type wavefront aberration measuring instrument 98 and an illuminance monitor (not shown) disclosed in, for example, international publication No. 2003/065428 pamphlet and the like are provided. Further, a pair of light receiving systems (not shown) are provided on the stage main body 92 so as to be opposed to the pair of light transmitting systems (not shown). In the present embodiment, aerial image measuring apparatus 45 (see fig. 7) is configured such that, in a state (including a contact state) in which wafer stage WST and measurement stage MST are within a predetermined distance in the Y-axis direction, illumination light IL transmitted through each aerial image measurement slit pattern SL of measurement plate 30 on wafer stage WST is guided by each light transmitting system (not shown) and received by the light receiving elements of each light receiving system (not shown) in measurement stage MST.

As shown in fig. 2B, a reference lever (hereinafter, referred to as "FD lever") 46 extends in the X-axis direction on the-Y-side end surface of the measurement table MTB. In the vicinity of one end and the other end in the longitudinal direction of the FD lever 46, reference gratings (for example, diffraction gratings) 52 are formed in a symmetrical arrangement with respect to the center line CL, respectively, with the Y-axis direction being the periodic direction. A plurality of reference marks M are formed on the FD lever 46. Each reference mark M is, for example, a two-dimensional mark having a size detectable by a primary alignment system or a secondary alignment system described later. Further, the surface of the FD lever 46 and the surface of the measurement table MTB are each covered with a liquid-repellent film (water-repellent film).

Reflection surfaces 19a and 19B (see fig. 2B) similar to wafer table WTB are formed on the + Y end surface and the-X end surface of measurement table MTB.

As shown in fig. 4 and 5, the exposure apparatus 100 according to the present embodiment includes a primary alignment system AL1, and the primary alignment system AL1 has a detection center at a position separated by a predetermined distance from the optical axis AX of the projection optical system PL toward the-Y side on the reference axis LV. The primary alignment system AL1 is fixed to the lower surface of a main frame, not shown. A secondary alignment system AL2 having detection centers arranged substantially symmetrically with respect to the straight line LV is provided on one side and the other side of the primary alignment system AL1 in the X axis direction₁，AL2₂And AL2₃，AL2₄. Secondary alignment system AL2₁～AL2₄The detection areas (or detection centers) are independently driven in the X-axis direction by driving mechanisms 601 to 604 (see fig. 7) fixed to the lower surface of a main frame (not shown) through a movable supporting member. Thus, primary alignment system AL1 and secondary alignment system AL2₁，AL2₂，AL2₃，AL2₄The relative position of the detection area in the X-axis direction can be adjusted. Further, a parallel straight line LA parallel to the X axis passing through the detection center of the primary alignment system AL1 shown in fig. 4 and the like coincides with the optical axis of the ranging axis B6 from the aforementioned interferometer 127.

In this embodiment, the alignment systems AL1, AL2₁～AL2₄For example, a Field Image Alignment (FIA) system of an Image processing system may be used. From alignment systems AL1, AL2₁～AL2₄The respective imaging signals are supplied to the main controller 20 through an alignment signal processing system not shown.

Note that the alignment systems are not limited to the FIA system, and it is needless to say that an alignment sensor capable of detecting scattered light or diffracted light generated from an object mark by irradiating coherent detection light to the object mark, or an alignment sensor capable of detecting two diffracted lights generated from the object mark by interfering with each other (for example, diffracted light of the same order or diffracted light in the same direction) may be used alone or in an appropriate combination.

Next, the configuration and the like of interferometer system 118 (see fig. 7) for measuring positional information of wafer stage WST and measurement stage MST will be described.

Interferometer system 118 includes, as shown in fig. 3, Y interferometer 16, X interferometers 126, 127, and 128, Z interferometers 43A and 43B, Y interferometer 18, and X interferometer 130 for measuring the position of wafer stage WST, and the like. The Y interferometer 16 and the three X interferometers 126, 127, 128 irradiate interferometer beams (ranging beams) B4 (B4) on the reflection surfaces 17a, 17B of the wafer table WTB₁，B4₂)、B5(B5₁，B5₂) B6, B7. Then, Y interferometer 16 and three X interferometers 126, 127, and 128 receive the reflected light, measure positional information of wafer stage WST in the XY plane, and supply the measured positional information to main control device 20.

Further, for example, X interferometer 126 irradiates reflection surface 17B with three distance measuring beams parallel to the X axis, including a pair of distance measuring beams B5 symmetrical with respect to an optical axis AX passing through projection optical system PL (in the present embodiment, also coinciding with the center of exposure area IA) and parallel to the X axis (refer to reference axis LH (fig. 4, 5, etc.)))₁，B5₂. The Y interferometer 16 irradiates the reflection surface 17a and the movable mirror 41 described later with three distance measuring beams including a pair of distance measuring beams B4 symmetrical with respect to the reference axis LV, the distance measuring beams being parallel to the Y axis₁，B4₂. As described above, in the present embodiment, a multi-axis interferometer having a plurality of measurement axes is used as each interferometer except for a part (for example, interferometer 128). Therefore, main controller 20 can calculate rotation information in the θ X direction (i.e., pitch), rotation information in the θ Y direction (i.e., roll), and rotation information in the θ z direction (i.e., yaw), in addition to the X and Y positions of wafer table WTB (wafer stage WST), based on the measurement results of Y interferometer 16 and X interferometer 126 or 127.

As shown in fig. 1, a movable mirror 41 having a concave reflecting surface is attached to the-Y side surface of the stage main body 92. As shown in fig. 2(a), the length of the movable mirror 41 in the X-axis direction is designed to be longer than the reflection surface 17a of the wafer table WTB.

A pair of Z interferometers 43A and 43B (see fig. 1 and 3) is provided opposite to the movable mirror 41. The Z interferometers 43A, 43B irradiate the two ranging beams B1, B2, respectively, through the movable mirror 41 onto fixed mirrors 47A, 47B, e.g. fixed to a frame (not shown) for supporting, e.g., the projection unit PU. Then, the optical path lengths of the respective reflected light measurement ranging beams B1, B2 are received. From the result, main controller 20 calculates the position of wafer stage WST in the four-degree-of-freedom (Y, Z, θ Y, θ Z) direction.

In the present embodiment, positional information (including rotation information in the θ z direction) of wafer stage WST (wafer table WTB) in the XY plane is mainly measured using an encoder system described later. Interferometer system 118 is used when wafer stage WST is located outside the measurement area of the encoder system (e.g., near unloading position UP and loading position LP shown in fig. 4 and the like). The correction is used for correcting (correcting) long-term fluctuation (for example, due to change of a scale with time) of the measurement result of the encoder system, or the like, in an auxiliary manner. Of course, interferometer system 118 and encoder system may be used together to measure the full position information of wafer stage WST (wafer table WTB).

As shown in fig. 3, Y interferometer 18 and X interferometer 130 of interferometer system 118 irradiate interferometer beams (ranging beams) onto reflection surfaces 19a and 19b of measurement stage MTB, and receive the respective reflected beams, thereby measuring positional information of measurement stage MST (including, for example, positional information on at least the X axis and the Y axis and rotation information in the θ z direction), and supplying the measurement results to main controller 20.

Next, the configuration of encoder system 150 (see fig. 7) for measuring positional information (including rotation information in the θ z direction) of wafer stage WST in the XY plane will be described.

In the exposure apparatus 100 of the present embodiment, as shown in fig. 4, four head units 62A to 62D are arranged in a state of extending in four directions from the nozzle unit 32. The head units 62A to 62D are fixed to a main frame for holding the projection unit PU in a suspended state via support members.

The head units 62A and 62C are respectively provided with a plurality of (nine in this case) Y heads 65 as shown in fig. 5₁～65₉And 64₁～64₉. More specifically, head units 62A and 62C each include a plurality of (here, seven) Y heads 65 arranged at intervals WD on reference axis LH₃～65₉And 64₁～64₇And a plurality of Y heads (two in this case) 65 arranged at intervals WD in parallel with the reference axis LH at positions on the-Y side of the nozzle unit 32 which are separated from the reference axis LH by a predetermined distance in the-Y direction₁，65₂And 64₈，64₉. Further, the Y head 65₂，65₃Inter and Y head 64₇，64₈The interval therebetween in the X-axis direction is also set to WD. Hereinafter, the Y head 65 is also appropriately set₁～65₉And 64₁～64₉Described as Y heads 65, 64, respectively.

A head unit 62A configured to use the Y scale 39Y₁And a multi-eye (here, nine-eye) Y linear encoder (hereinafter, appropriately referred to simply as "Y encoder" or "encoder") 70A (see fig. 7) for measuring the position (Y position) of wafer stage WST (wafer table WTB) in the Y-axis direction. Similarly, head unit 62C constitutes a multi-eye (here, nine-eye) Y encoder 70C (see fig. 7) for measuring the Y position of wafer stage WST (wafer table WTB) using Y scale 39Y2 described above. Here, the X-axis distance WD of the nine Y heads 65, 64 (more precisely, the irradiation points on the scale of the measuring beams emitted from the Y heads 65, 64) provided in the head units 62A, 62C is set to be smaller than that of the Y scale 39Y₁，39Y₂The width in the X-axis direction (more precisely, the length of the grating lines 38) is slightly narrower by half. Therefore, at least two heads of the nine Y heads 65 and 64 face the corresponding Y scale 39Y at any time during exposure or the like₁，39Y₂. I.e. emitted by nine Y read heads 65, 64At least two of the measuring beams can be irradiated to the corresponding Y scale 39Y₁，39Y₂。

As shown in fig. 5, head unit 62B includes a plurality of (here, seven) X heads 66 disposed on the + Y side of nozzle member 32 (projection unit PU) and spaced apart from reference axis LV by predetermined interval WD₈～66₁₄. Head unit 62D includes a plurality of (here, seven) X heads 66 disposed at predetermined intervals WD on reference axis LV, on the-Y side of primary alignment system AL1 disposed on the opposite side of head unit 62B from nozzle member 32 (projection unit PU), and on reference axis LV₁～66₇. Hereinafter, the X head 66 will also be described₁～66₁₄Appropriately described as X read head 66.

A head unit 62B configured to use the X scale 39X₁X linear encoder (hereinafter, appropriately referred to simply as "X encoder" or "encoder") 70B for measuring the position (X position) of wafer stage WST (wafer table WTB) in the X-axis direction for a plurality of eyes (here, seven eyes) (see fig. 7). The head unit 62D is configured using the X scale 39X₂X encoder 70D (see fig. 7) for measuring the multi-eye (here, seven-eye) position X of wafer stage WST (wafer table WTB).

Here, the interval WD between adjacent X heads 66 (more precisely, the irradiation points of the measuring beams emitted from the X heads 66 on the scale) provided in each of the head units 62B and 62D is set to be larger than the X scale 39X₁，39X₂The width in the Y-axis direction (more precisely, the length of the grating lines 37) is slightly narrower by half. Therefore, at least two heads of the X heads 66 provided in the head units 62B and 62D respectively face the corresponding X scales 39X during exposure except for switching (connection) and the like described below₁，39X₂. That is, at least two of the measuring beams emitted from the seven X heads 66 can be irradiated to the corresponding X scale 39X₁，39X₂. Further, the X head 66 on the most-Y side of the head unit 62B₈X head 66 closest to + Y side of head unit 62D₇Is set to be wider than the width of wafer table WTB in the Y-axis directionSlightly narrower so as to be switchable (continuous) between the two X heads by movement of wafer stage WST in the Y-axis direction.

In the arrangement of the X heads 66 according to the present embodiment, when the above switching (connection) is performed, only the X head 66 closest to the-Y side among the X heads 66 belonging to the head unit 62B₈Corresponding X scale 39X₁In the opposite direction, only the X head 66 closest to the + Y side among the X heads 66 belonging to the head unit 62D₇Corresponding X scale 39X₂Are opposite. That is, only one of the X heads 66 is associated with each X scale 39X₁，39X₂Are opposite. Therefore, the distance between the head units 62B and 62D can be reduced by the distance WD or more, and the X head 66 can be eliminated during switching (connection)₈And an X read head 66₇While facing away from the corresponding X scale, an X read head 66₈And an X read head 66₉At least one of them also faces the corresponding X scale at the same time.

In the present embodiment, as shown in fig. 4, head units 62F and 62E are provided on the-Y sides of head units 62A and 62C, respectively, at a predetermined distance. The head units 62F and 62E are fixed in a suspended state to a main frame (not shown) for holding the projection unit PU via a support member.

As shown in fig. 5, the head unit 62E includes seven Y heads 67₁～67₇. More specifically, the head unit 62E is provided with a secondary alignment system AL2₁Five Y heads 67 arranged on the-X side of the reference axis LA at substantially the same intervals as the intervals WD₁～67₅And a secondary alignment system AL2 disposed parallel to the reference axis LA at a predetermined distance from the reference axis LA in the + Y direction with a gap WD therebetween₁Two Y read heads 67 of + Y side of₆，67₇. Y read head 67₅，67₆The interval therebetween in the X-axis direction is also set to WD. Hereinafter, the Y head 67 is also appropriately set₁～67₇Described as the Y head 67.

The head unit 62F includes seven Y heads that are symmetrical with the head unit 62E about the reference axis LV, and are arranged symmetrically with the seven Y heads 67 about the reference axis LVHead 68₁～68₇. Hereinafter, the Y head 68 is also appropriately set₁～68₇Described as Y head 68.

At least two of the Y heads 67, 68 respectively face the Y scale 39Y during the alignment operation₂，39Y₁. That is, at least two of the measuring beams emitted from the seven Y heads 67, 68 can be irradiated to the Y scale 39Y at any time during alignment₂，39Y₁. The Y position (and θ z rotation) of wafer stage WST is measured by Y heads 67, 68 (i.e., Y encoders 70E, 70F constituted by these Y heads 67, 68).

In the present embodiment, when the baseline measurement of the secondary alignment system is performed, the secondary alignment system AL2 is aligned in the X-axis direction₁，AL2₄Adjacent Y read head 67₅，68₃A pair of reference gratings 52 of the FD rod 46 are respectively opposed to each other, and a Y head 67 opposed to the pair of reference gratings 52 passes₅，68₃The Y position of the FD lever 46 is measured with the position of the respective reference grating 52. Hereinafter, the Y head 67 is defined by the pair of reference gratings 52 facing each other₅，68₃The encoder constituted is called a Y linear encoder (appropriately abbreviated as "Y encoder" or "encoder") 70E₂，70F₂. For identification, the mark is marked by the Y scale 39Y₂，39Y₁Y encoders 70E, 70F formed by the facing Y heads 67, 68 are referred to as Y encoder 70E₁，70F₁。

The measured values of the linear encoders 70A-70F are supplied to the main control device 20, and the main control device 20 is configured to control the linear encoders 70A-70D based on three or 70B, 70D, 70E₁，70F₁Controls the position of wafer stage WST in the XY plane based on the three measured values of (1), and is based on linear encoder 70E₂，70F₂Controls the rotation of the FD lever 46 in the θ z direction.

As shown in fig. 4 and 6, the exposure apparatus 100 of the present embodiment is provided with a multi-spot focal position detection system of an oblique incidence type (hereinafter, simply referred to as "multi-spot AF system") similar to that of the irradiation system 90a and the light receiving system 90b, for example, as disclosed in U.S. Pat. No. 5,448,332 and the like. In the present embodiment, as an example, the irradiation system 90a is disposed on the + Y side of the-X end of the head unit 62E, and the light receiving system 90b is disposed on the + Y side of the + X end of the head unit 62F in a state opposed thereto. Further, the multi-spot AF system (90a, 90b) is fixed to the lower surface of a main frame for holding the projection unit PU.

A plurality of detection points of a multipoint AF system (90a, 90b) are arranged at predetermined intervals in the X-axis direction on a detection surface. In the present embodiment, for example, the detection points are arranged in a matrix of M rows and M columns (M is the total number of detection points) or two rows and N columns (N is M/2). Fig. 4 and 6 do not individually show a plurality of detection points to which the detection beams are irradiated, but show an elongated detection area (beam area) AF extending in the X-axis direction between the irradiation system 90a and the light receiving system 90 b. Since the length of the detection area AF in the X axis direction is set to be the same as the diameter of the wafer W, the substantially entire Z axis direction position information (surface position information) of the wafer W can be measured by scanning the wafer W only once in the Y axis direction.

As shown in fig. 6, a pair of Z position measuring surface position sensor heads (hereinafter, simply referred to as "Z heads") 72a, 72b, and 72c, 72d are provided in the vicinity of both ends of the detection area AF of the multipoint AF system (90a, 90b) so as to be symmetrical with respect to the reference axis LV. These Z heads 72a to 72d are fixed to the lower surface of a main frame, not shown.

For example, the optical displacement sensor heads used in the CD drive and the like are used for the Z heads 72a to 72 d. Z heads 72a to 72d irradiate wafer table WTB with a measuring beam from above, and receive the reflected light thereof to measure positional information (surface positional information) of the surface of wafer table WTB in the Z-axis direction orthogonal to the XY plane at the irradiation point. In the present embodiment, a reflection-type diffraction grating (constituting the Y scale 39Y) is used as the measuring beam of the Z head₁，39Y₂) The composition of the reflection.

Furthermore, the foregoing descriptionThe head units 62A, 62C are respectively provided with nine Y heads 65 as shown in fig. 6_j，64_iNine Z heads 76 are provided at the same X position and shifted Y position (i, j is 1 to 9)_j，74_i(i, j ═ 1 to 9). Here, five Z heads 76 respectively belonging to the outer sides of the head units 62A, 62C₅～76₉，74₁～74₅The reference axis LH is arranged in parallel with the reference axis LH at a predetermined distance in the + Y direction. The innermost Z head 76 to which each head unit 62A, 62C belongs₁，76₂And 74₈，74₉The remaining Z heads 76 disposed on the + Y side of the projection unit PU₃，76₄And 74₆，74₇Are respectively arranged at the Y head 65₃，65₄And 64₆，64₇the-Y side of (1). Nine Z heads 76 belonging to head units 62A and 62C, respectively_j，74_iAnd are arranged symmetrically with respect to the reference axis LV. In addition, each Z head 76_j，74_iThe head of the optical displacement sensor is used as the Z heads 72a to 72 d.

Nine Z heads 76 provided in head units 62A and 62C, respectively_j，74_i(more precisely, the distance in the X-axis direction between the irradiation points of the measuring beam on the scale by the Z head) is set to be equal to the distance WD in the X-axis direction between the Y heads 65 and 64. Therefore, nine Z heads 76 are provided in the same manner as the Y heads 65 and 64_j，74_iAt least two heads respectively facing corresponding Y scales 39Y at any time during exposure₁，39Y₂. That is, nine Z heads 76_j，74_iAt least two of the emitted measuring beams can be irradiated on the corresponding Y scale 39Y₁，39Y₂。

The Z heads 72a to 72d and the Z head 74₁～74₉And Z head 76₁～76₉As shown in FIG. 7, the transmission signal processing/selecting device 170 is connected to the main controller 20, and the Z heads 72a to 72d and 74 from the Z head 72 through the signal processing/selecting device 170₁～74₉And Z head 76₁～76₉An arbitrary Z head is selected and set to an operating state, and the surface position information detected by the Z head set to the operating state is received through the signal processing/selecting device 170. In the present embodiment, the Z heads 72a to 72d and the Z head 74 are included₁～74₉Z head 76₁～76₉And signal processing/selecting device 170, and surface position measurement system 180 (a part of measurement system 200) for measuring positional information of wafer stage WST in the Z-axis direction and in the tilt direction with respect to the XY plane.

Further, The exposure apparatus 100 of The present embodiment is provided with a pair of reticle alignment detection systems 13A and 13B (not shown in fig. 1, see fig. 7) including a ttr (through The tilt) alignment system using light of an exposure wavelength above The reticle R. The detection signals of the reticle alignment detection systems 13A and 13B are supplied to the main controller 20 through an alignment signal processing system not shown.

Fig. 7 shows a main configuration of a control system of the exposure apparatus 100. The control system is mainly a main control device 20 composed of a microcomputer (or a workstation) for integrating the entire device. In fig. 7, various sensors provided on measurement stage MST, such as uneven illuminance sensor 94, aerial image measuring instrument 96, and wavefront aberration sensor 98, are collectively referred to as a sensor group 99.

Since exposure apparatus 100 of the present embodiment employs the arrangement of the X and Y scales on wafer table WTB and the arrangement of the X and Y heads, as described above, Y scale 39Y is used in the range of effective stroke of wafer stage WST (i.e., the range of movement for alignment and exposure in the present embodiment) as shown in the examples of fig. 8a and 8B₁，39Y₂The Y heads 65 and 64 (head units 62A and 62C) or the Y heads 68 and 67 (head units 62F and 62E) are always opposed to each other, and the X head 66 (head unit 62B or 62d) is always opposed to the X scale 39X₁，39X₂Any one of the above. In fig. 8(a) and 8(B), the heads facing the corresponding X scale or Y scaleIndicated by the solid circled boxes.

As described above, each of the head units 62A to 62F can always make at least two heads face the corresponding scale except for a part thereof (more precisely, can always make at least two measuring beams irradiate the corresponding scale except for a part thereof). Therefore, the main controller 20 uses at least two heads facing the scale as a pair for each of the head units 62A to 62F. The main controller 20 monitors the measurement values of the two heads as needed, and represents the measurement value of one of the two heads as the measurement value of the head pair (or the head unit to which the two heads belong). For example, the main controller 20 sets, as the priority head, the head that first faces the scale out of the two heads, and sets, as the auxiliary head, the head that subsequently faces the scale. Alternatively, the main controller 20 may set the head near the center of the scale in the direction orthogonal to the longitudinal direction (X-axis direction in the case of an X-scale) as the priority head and the remaining heads as the auxiliary heads. The main controller 20 normally represents the measurement value of the priority head as the measurement value of the head pair (or head unit), and then represents the measurement value of the auxiliary head as the measurement value of the head pair (or head unit) when an abnormality occurs in the output (measurement value) of the priority head. The main controller 20 monitors the measurement values of the six head units according to this processing method.

The main controller 20 monitors the photoelectric conversion signal output from the light receiving element in the head, and determines that the signal is abnormal when the photoelectric conversion signal is not present (the signal intensity is zero) or when the signal intensity is at an extremely low level, and otherwise determines that the signal is normal.

Therefore, main controller 20 can use at least three of encoders 70A to 70D, or 70B, 70D, and 70E, in the effective stroke range of wafer stage WST described above₁，70F₁Three of the measured values of (a) control motors constituting stage drive system 124 to control wafer stage WST at high accuracyPosition information in the XY plane (including rotation information in the θ z direction).

When main controller 20 drives wafer stage WST in the X-axis direction as indicated by the white arrow in fig. 8(a), the head pair of Y heads 65 and 64 for measuring the position of wafer stage WST in the Y-axis direction is sequentially switched to the adjacent head pair as indicated by arrow e1 in the figure. More specifically, as for the Y head 65, a head pair 65 framed by a solid circle is provided₃，65₄Switching to the reading head pair 65 framed by a dashed circle₄，65₅With respect to the Y head 64, the head pair 64 framed by the solid circles₃，64₄Switching to the reading head pair 64 framed by a dashed circle₄，64₅. Here, one of the pair of heads before switching and the pair of heads after switching (65)₄，64₄) Are common.

In the present embodiment, in order to smoothly switch (connect) the Y heads 65, 64, two heads among the Y heads 65, 64 included in the head units 62A, 62C are switched as described above (for example, in the example of fig. 8(a), the Y head 65 is used as the Y head 65)₃And 65₅、64₃And 64₅) Is set to be closer to the Y scale 39Y (twice the interval WD between adjacent heads)₁，39Y₂The width in the X-axis direction is narrow. In other words, the interval WD between adjacent Y heads is set to be smaller than the Y scale 39Y₁，39Y₂Half of the width in the X-axis direction is narrow.

In the case of Sec-BCHK (top of batch), which will be described later, main controller 20 sequentially switches the pair of heads in Y heads 67 and 68 for measuring the position of wafer stage WST in the Y axis direction to the adjacent pair of heads in the same manner as described above when driving wafer stage WST in the X axis direction.

In the present embodiment, as described above, the distance WD between adjacent X heads 66 of head units 62B and 62D is set to be larger than that of X scale 39X₁，39X₂Since the width in the Y-axis direction is half as narrow, the main controller 20 carries the wafer as indicated by the white arrow in fig. 8(B) in the same manner as described aboveWhen stage WST is driven in the Y-axis direction, the head pair of X heads 66 for measuring the position of wafer stage WST in the X-axis direction is sequentially switched to the adjacent head pair as indicated by arrow e2 in the figure. In particular, the read head pair 66 is framed by a solid circle₉，66₁₀Switching to the read head pair 66 framed by the dashed circle₈，66₉. Here, one head 66 is provided in the pair of heads before switching and the pair of heads after switching₉Are common.

In the present embodiment, the encoder head used for measuring the position of wafer stage WST as it moves is switched from a certain head pair (e.g., Eh1, Eh2) to another head pair (Eh2, Eh3) including one head (Eh 2). However, this is not limited to this, and a modification may be adopted in which a certain pair of heads (e.g., Eh1, Eh2) is switched to another pair of heads (Eh3, Eh4) that does not include a common head. In this modification, as in the above-described embodiment, the measurement values of the priority heads may be represented as the measurement values of the head pairs (or the head units to which the heads belong) in the normal case, and the measurement values of the auxiliary heads may be represented as the measurement values of the head pairs (or the head units to which the heads belong) in the abnormal case.

The cause of the abnormality in the measurement value of the encoder can be largely divided into two causes, that is, a cause due to a malfunction of the encoder head (head) and a cause due to an abnormality of the scale irradiated with the measurement beam. In the former case, a mechanical failure of the head is typically exemplified. Specifically, the failure of the head itself, the failure of the measuring beam light source, the adhesion of water droplets to the head, and the like can be given. Even if the measuring beam light source does not fail, the extremely low intensity of the measuring beam can be interpreted as a cause of the reading head. On the other hand, the latter example includes a case where liquid in the liquid immersion area remains on the surface of the scale, foreign matter such as foreign matter adheres to the liquid, and the measuring beam scans the remaining liquid or the foreign matter adhering to the liquid.

The method of causing the head pair composed of the priority head and the auxiliary head to face at least one corresponding scale at any time in the present embodiment is effective for abnormality of the measurement value due to malfunction of the head, and also effective for abnormality of the measurement value due to abnormality of the scale.

In addition, since the optical path lengths of the two light beams interfering with each other are extremely short and substantially equal, the encoders 70A to 70F used in the present embodiment can almost ignore the influence of air fluctuation. The analysis capability of each encoder is, for example, about 0.1 nm.

Next, a description will be given mainly of a secondary alignment system AL2 performed before starting processing of a batch of wafers (batch head)_n(n-1 to 4) (hereinafter also referred to as Sec-BCHK (top of batch) as appropriate). Here secondary alignment system AL2_nThe base line of (A) indicates each secondary alignment system AL2 with (detection center of) the primary alignment system AL1 as a reference_nRelative position of (detection center of). In addition, secondary alignment system AL2_n(n is 1 to 4), and the position in the X-axis direction is set according to the irradiation pattern data of the wafers in the lot, for example.

a. When Sec-BCHK (top of batch) is performed, the main controller 20 first performs the process as shown in FIG. 9A. The primary alignment system AL1 detects a specific alignment mark (see the star mark in fig. 9 a) on the wafer W (processed wafer) at the head of the lot, and the detection result and the detection-time encoders 70A and 70E₁，70F₁The measured values are assigned to each other and stored in a memory. In the state of fig. 9(a), the positions of wafer stage WST in the XY plane are respectively opposed to Y scales 39Y₁，39Y₂Two Y read head pairs 68 framed by black circles₃，68₄And 67₄，67₅(encoder 70E)₁，70F₁) And a scale 39X facing the X₂Black circled X-read head pair 66₃，64₄(encoder 70D) is controlled by main control device 20.

b. Next, main controller 20 moves wafer stage WST in the-X direction by a predetermined distance, and uses the secondary alignment system as shown in FIG. 9(B)AL2₁The specific alignment mark (see the star mark in fig. 9B) is detected, and the detection result is associated with the detection-time encoders 70A and 70E₁，70F₁The measured values are assigned to each other and stored in a memory. In the state of fig. 9(B), the positions of wafer stage WST in the XY plane are respectively opposed to Y scales 39Y₁，39Y₂Two Y read head pairs 68 framed by black circles₁，68₂And 67₁，67₂(encoder 70E)₁，70F₁) And a scale 39X facing the X₂Black circled X-read head pair 66₃，64₄(encoder 70D).

c. Similarly, main controller 20 sequentially moves wafer stage WST in the + X direction to use the remaining secondary alignment system AL2₂，AL2₃，AL2₄Sequentially detecting the specific alignment marks, and comparing the detection result with the encoders 70A, 70E during the detection₁，70F₁The measured values are sequentially assigned with corresponding relations and then stored in a memory.

d. Next, the main controller 20 calculates each secondary alignment system AL2 based on the processing result of the above-mentioned a and the processing result of the above-mentioned b or c_nA baseline of (c).

As described above, since the wafers W (processed wafers) at the front of the lot can be used, the wafers W can be aligned by the primary alignment system AL1 and the secondary alignment systems AL2_nThe same alignment mark on the wafer W is detected to obtain each secondary alignment system AL2_nAs a result, the detection bias error between the alignment systems due to the processing can be corrected by the processing.

In the present embodiment, since the head units 62E, 62 are provided with the seven Y heads 67, 68 having different positions in the X axis direction, respectively, the secondary alignment systems AL2 are measured_nWhen using primary alignment system AL1, and in turn secondary alignment system AL2_nIn the case of detecting a specific alignment mark on a wafer according to the opposing directionOn the Y scale 39Y₁，39Y₂Y read head pair 68, 67 (encoder 70F)₁，70E₁) The Y position and θ z rotation of wafer stage WST at the time of the detection are measured and managed. At this time, the X position of wafer stage WST is based on the X scale 39X facing the X₂The X read head pair 66 (encoder 70D) is measured and managed.

In addition, instead of the alignment mark of the wafer, for example, the fiducial mark FM of the measurement plate 30 on the wafer stage WST or the fiducial mark M of the FD lever 46 on the measurement stage MST may be used to perform the secondary alignment system AL2_nIs measured at the baseline.

The exposure apparatus 100 of the present embodiment performs a parallel processing operation using the wafer stage WST and the measurement stage MST in the same procedure as the exposure apparatus disclosed in the embodiment of the aforementioned pamphlet of international publication No. 2007/097379. The parallel processing operation is the same as the exposure apparatus disclosed in the embodiment of the aforementioned pamphlet of international publication No. 2007/097379 except for the following two points, and therefore, a detailed description thereof is omitted.

First, when an error occurs in the output of any one of the priority heads (X head or Y head) used for the position measurement of the encoder system for measuring the position information of wafer stage WST when wafer stage WST is located in the effective area, the main controller 20 uses the measurement values of the priority head and the auxiliary head constituting the head pair as the measurement values of the head pair (or the head units to which the two heads belong) in the manner described above.

Second, for example, at the time of step-and-scan exposure operation between irradiation areas of wafer stage WST, head switching is performed such that an encoder head used for measuring, for example, the X position of wafer stage WST is switched from a certain head pair (e.g., Eh1, Eh2) to another head pair (Eh2, Eh3) including one head (Eh 2).

As described above, according to exposure apparatus 100 of the present embodiment, wafer stage WST is positioned at the position described aboveIn the effective stroke range, a Y scale 39Y provided on wafer stage WST₁，39Y₂Since two or more corresponding Y heads face each other at any time, main controller 20 can use the measurement result of at least one of the two Y heads to measure wafer stage WST on Y scale 39Y at any time₁，39Y₂The periodic direction (Y-axis direction) of the grating portion and the rotation information in the θ z direction. In addition, when wafer stage WST is positioned within the effective stroke range, the exception is partially made (wafer stage WST is positioned in X head 66 of head unit 62B)₈X read head 66 of read head unit 62D₇Switchable position), X scale 39X provided on wafer stage WST₁，39X₂Since two or more corresponding X heads face each other as needed, main controller 20 can measure wafer stage WST on X scale 39X as needed using the measurement result of at least one of the two X heads₁，39X₂The periodic direction (X-axis direction) of the grating portion.

When an abnormality due to head abnormality (or abnormality due to scale abnormality) occurs in the measurement information of the priority head of at least two heads positioned in the effective region (grating portion) on each scale, the main controller 20 switches the measurement information that is preferentially used for the position control of the wafer stage WST from the measurement information of the priority head to the measurement information of the auxiliary head. This makes it possible to reliably measure the positional information of wafer stage WST in the periodic direction of the grating portion of each scale.

In the exposure apparatus according to the present embodiment, the encoder system 150 included in the measurement system 200 includes the head units 62E and 62F (disposed in the primary alignment system AL1 and the secondary alignment system AL2, respectively)₁～AL2₄Both outer sides of the detection region) of the seven Y heads 67, 68 whose positions in the X axis direction are different. The main controller 20 is also aligned with the pair of Y scales 39Y₁，39Y₂Respectively opposed pairs 68, 67 of Y readheads (Y linear encoders 70E)₁，70F₁) Measuring the position of wafer stage WST in the Y-axis directionPosition information (and position information in the θ z direction).

Therefore, for example, when Sec-BCHK (batch top) is performed, the main controller 20 uses the primary alignment system AL1 and the secondary alignment system AL2 to perform the above-described batch top₁～AL2₄Y linear encoder 70E having excellent short-term stability of measurement can be used even when a specific alignment mark on wafer W held by wafer stage WST (or fiducial mark FM on wafer stage WST) is detected and wafer stage WST is moved in the X-axis direction₁，70F₁The position of wafer stage WST in at least the Y-axis direction (and position information in the θ z direction) is measured. Thus, master control device 20 can be based on alignment system AL1, as well as alignment system AL2₁～AL2₄Respective detection results, and a Y-line encoder 70E for the detection₁，70F₁The position information of the mark (the specific alignment mark (or the reference mark FM on the wafer stage WST)) in the Y-axis direction is obtained with good accuracy. The position of wafer stage WST in the X-axis direction at Sec-BCHK (top of batch) is opposite to X scale 39X₂Is measured by the X readhead pair 66 (encoder 70D). Therefore, the secondary alignment system AL2 can be obtained with high accuracy for each lot₁～AL2₄The base lines (X-axis direction and Y-axis direction) of (a).

In the present embodiment, the secondary alignment system AL2 is measured at a predetermined time interval (here, every time a wafer is replaced)₁～AL2₄The base lines (X-axis direction and Y-axis direction) of (a). Then, based on the result of the latest baseline and wafer alignment (EGA) obtained in the above-described manner, the pattern of the reticle R can be transferred to a plurality of irradiation regions on the wafer W with good accuracy (overlay accuracy) by repeating the inter-irradiation-region moving operation (moving the wafer stage WST to the scanning start position (acceleration start position) for exposing each irradiation region on the wafer W) and the scanning exposure operation (transferring the pattern formed on the reticle R to each irradiation region by the scanning exposure method). Further, in the present embodiment, since the exposure with high resolution can be realized by the immersion exposure, the fine pattern can be transferred onto the wafer W with good precision even at this point。

In the exposure apparatus 100 according to the present embodiment, the two innermost Y heads 67 of the seven Y heads 67 and 68 provided in the head units 62E and 62F, respectively, are the Y heads 67₆，67₇And 68₁，68₂The position in the Y-axis direction is different from the other heads. Thus, the two innermost Y heads 67 can be coupled₆，67₇And 68₁，68₂Arranged in alignment systems AL1, AL2₁～AL2₄The surrounding empty space, i.e. capable of cooperating with the alignment systems AL1, AL2₁～AL2₄Is configured.

The distance in the X axis direction between the seven Y heads 67 and 68 provided in the head units 62E and 62F is smaller than that on the Y scale 39Y₁，39Y₂Since the width in the X-axis direction (more precisely, the length of the grating lines 38) is half as narrow, when the wafer stage WST moves in the X-axis direction, the pair of Y heads used for the position measurement in the Y-axis direction of the wafer stage WST can be switched to the adjacent pair of Y heads without any trouble as it moves (one head in the pair of Y heads is common to the previous pair of Y heads), and the measurement values are continued before and after the switching. Thus, at least two of the Y heads 67, 68 respectively face the Y scale 39Y at the time of Sec-BCHK, etc. described above₂，39Y₁By these Y head pairs 67, 68 (i.e., Y encoder 70E constituted by these Y head pairs 67, 68)₁，70F₁) The Y position (and θ z rotation) of wafer stage WST is measured.

The main controller 20 is also arranged in alignment systems AL1 and AL2₁～AL2₄When detecting the alignment mark on the wafer W, two of the seven Y heads 67 and 68 of the head units 62E and 62F are selected to be respectively aligned with the Y scale 39Y₂，39Y₁Two of the opposing Y heads 67, 68 and the X scale 39X corresponding to the two are selected from the plurality of X heads 66 of the head units 62B, 62D₂，39X₁The opposing X head 66 controls the position and rotation (θ z rotation) of wafer stage WST in the XY plane based on the measurement values of the selected two Y head pairs and the measurement value of the selected X head pairTurn).

Modifications

In the above-described embodiment, in order to stably and accurately measure positional information of wafer stage WST in the XY moving plane, two encoder heads (heads) are constantly opposed to a common scale. Next, the measurement value of the priority head of the pair of heads configured by the two heads is used, and when an abnormality occurs in the measurement value of the priority head due to a malfunction of the head (or a scale abnormality), the measurement value of the other auxiliary head is used. However, not limited to this, various modifications are conceivable as a measurement method using the measurement values of the two heads of the priority head and the auxiliary head at any time.

Hereinafter, several representative modifications will be described with reference to fig. 10(a) to 12. In fig. 10 a to 12, a scale SY (i.e., a wafer stage) moves in the-X direction. The scale SY is a Y scale, and the head is a Y head.

In the first modification, two heads of the priority head and the auxiliary head are set as one set (referred to as a head set), and at least one head set is made to face the scale as needed. In this first modification, as shown in fig. 10 a, a head group Hs1 composed of two heads Eh1, Eh2 arranged close to each other in the longitudinal direction (Y-axis direction) of the scale SY and a head group Hs2 composed of two other heads Eh3, Eh4 arranged close to each other in the Y-axis direction are opposed to the single scale SY. In this first modification, a plurality of head groups are prepared, each of which is composed of two heads close to each other in the Y-axis direction, and the head groups are arranged in parallel to the X-axis direction at intervals narrower than the effective width of the scale SY. Thus, a reading head set is opposite to the scale SY at any time.

When the scale SY (i.e., the wafer stage) moves in the-X direction from the state shown in fig. 10(a), the head set Hs1 is disengaged from the scale SY. More precisely, the irradiation point of the measuring beam emitted by the two heads Eh1 and Eh2 constituting the head set Hs1, that is, the measuring point of the heads Eh1 and Eh2, is deviated from the effective region of the scale SY. Therefore, before the head set Hs1 is detached from the scale SY, the head set that manages the stage position is switched from the head set Hs1 to the head set Hs2 by the main control device 20.

This first modification is effective for abnormality of the measurement value due to malfunction of the head, and also effective for abnormality of the measurement value due to abnormality of the scale.

According to a second modification of the above-described first modification, as shown in fig. 10 (B). While the first modification employs a configuration in which two heads constituting a head group scan different measurement points, the second modification employs a configuration in which two heads constituting a head group scan the same measurement point. Thus, in the first modification, the two heads indicate different measurement values, whereas in the second modification, the two heads typically indicate mutually equal measurement values. With the configuration of the second modification, even if an abnormality occurs in the measurement value of one priority head of the two heads constituting the head group due to a mechanical failure of the priority head, the normal measurement value of the other auxiliary head can be used as the measurement value of the head group. Therefore, no abnormality is detected as a result of measurement by the head group.

In addition, the second modification differs from the first modification only in that the positions of the measurement points of the two heads constituting the head group are the same or different. Therefore, the arrangement of the head groups and the heads constituting the head groups in the second modification may be the same as that in the first modification. Thus, the switching process steps are also the same.

In the first and second modifications, the two heads constituting the head group are arranged side by side in the periodic direction (Y-axis direction) of the scale. In accordance with these examples, it is also conceivable to arrange the scale in a direction (X-axis direction) orthogonal to the scale period direction.

Fig. 11(a) shows a third modification corresponding to the first modification of fig. 10 (a). In the third modification, as in the first modification, two heads of the priority head and the auxiliary head are grouped, and at least one head group is made to face the scale as needed. However, in fig. 11 a, unlike the first modification, a head group Hs1 including two heads Eh1, Eh2 arranged close to each other in the effective width direction (X-axis direction) of the scale SY and a head group Hs2 including two other heads Eh3, Eh4 arranged close to each other in the X-axis direction face one scale SY. In this third modification, a plurality of head groups are prepared which are constituted by two heads which are close to each other in the X-axis direction, and the head groups are arranged parallel to the X-axis direction such that one head group always faces the scale SY. However, as shown in fig. 11 a, the interval between two adjacent head groups is set such that irradiation points (measurement points) of the measurement beams emitted from the two head groups (four heads in total constituting the head group) are located within the effective region of the scale SY.

When scale SY (i.e., wafer stage) moves in the-X direction from the state shown in fig. 11(a), head Eh1 is separated from the effective region of scale SY. Here, assuming that the head Eh1 is selected as the priority head of the head group Hs1, the main control device 20 switches the priority head to the head Eh2 when the head is disengaged from the scale SY. When the scale SY is further moved in the-X direction, then the measurement point of the readhead Eh2 is disengaged from the scale SY. Therefore, at the latest before this point in time, that is, before the measurement points of the two heads Eh1 and Eh2 constituting the head set Hs1 are separated from the scale SY, the head set that manages the stage position is switched from the head set Hs1 to the head set Hs 2.

This third modification is effective for abnormality of the measurement value due to malfunction of the head and also effective for abnormality of the measurement value due to abnormality of the scale, as in the first modification.

According to a fourth modification to the above-described third modification, as shown in fig. 11 (B). As is clear from a comparison between fig. 11(B) and fig. 11(a), the third modification employs a configuration in which two heads constituting a head group scan different measurement points, whereas the fourth modification employs a configuration in which the same measurement point is scanned. Therefore, in the configuration of the third modification, the two heads indicate different measurement values, whereas in the configuration of the fourth modification, the two heads normally indicate mutually equal measurement values. By adopting the configuration of the fourth modification, even if an abnormality occurs in the measurement value of one priority head of the two heads constituting the head group due to a mechanical failure of the priority head, the normal measurement value of the other auxiliary head can be used, and therefore, the abnormality is not detected as the measurement result of the head group.

Further, the difference between the fourth modification and the third modification is only the same or different in the positions of the measurement points of the two heads constituting the head group. Therefore, the arrangement of the head groups and the heads constituting the head groups in the fourth modification may be the same as that in the third modification. Thus, the switching process steps are also the same.

As is clear from a comparison between fig. 11(B) and fig. 10(B), the fourth modification and the second modification differ only in the direction of approach of the two heads constituting the head group, and therefore the same effects are obtained.

In the third modification of fig. 11 a, the arrangement interval between two adjacent head groups is set to an interval at which the irradiation points (measurement points) of the measurement beams emitted from the two head groups (four heads in total constituting the head group) are located within the effective region of the scale SY. However, in the switching process of the head groups, as shown in fig. 12, the arrangement interval of the adjacent two head groups may be set to an arrangement interval at which the three heads (Eh2, Eh3, Eh4) of the one head (Eh2) of the two heads (Eh1, Eh2) constituting one head group (Hs2) and the two heads (Eh3, Eh4) constituting the other head group (Hs1) face the scale SY.

In these four modifications, the head group including one priority head and one auxiliary head is used, but the number of auxiliary heads is not limited to one, and a plurality of auxiliary heads may be provided. When the above-mentioned structure is adopted, the reliability of the measuring result can be improved because more measuring data can be detected. Further, in the above-described four modifications, when the plurality of heads in the observation head group observe the same position in the traverse direction of the scale (the X-axis direction in these modifications), it is not possible to give the rank in the direction of "giving priority to the head that becomes effective first", "giving priority to the head that is close to the center line of the scale". Therefore, it is preferable to determine a fixed priority in the head group in advance.

The configuration of each measuring device such as the encoder system described in the above embodiments is merely an example, and the present invention is not limited to this. For example, in the above-described embodiment, an encoder system having a configuration in which a grating portion (X scale, Y scale) is provided on a wafer stage (wafer stage) and an X head and a Y head are arranged so as to face each other outside the wafer stage is exemplified, but the present invention is not limited to this, and an encoder system having a configuration in which an encoder head is provided on a wafer stage and a two-dimensional grating (or a one-dimensional grating portion arranged in two dimensions) is arranged so as to face each other outside the wafer stage as disclosed in, for example, U.S. patent application publication No. 2006/0227309 and the like may be adopted. In this case, at least two encoder heads may be provided at a plurality of positions, for example, at four corners, of the wafer stage, and the position of the wafer stage may be controlled in the same manner as in the above-described embodiments and modifications, with one of the at least two encoder heads serving as a priority head and the remaining at least one encoder head serving as an auxiliary head. In addition, the at least two encoder heads may be disposed close to each other on the wafer stage or at a predetermined interval. Particularly, the latter can be arranged in the radial direction from the center of the wafer stage, for example.

Further, since the grating surface of the two-dimensional grating or the like provided outside the wafer stage faces downward, it is not necessary to consider at all that the liquid in the liquid immersion area remains and foreign matter such as impurities hardly adheres. Therefore, since it is not necessary to consider abnormality in the output of the encoder head due to abnormality of the scale, the control device for switching the heads only needs to monitor the output abnormality of the priority head due to malfunction of the head.

In the above embodiment and modification, the encoder head and the Z head are described as being provided separately, but each encoder head may be provided with a Z head, and each encoder head may be provided with a head (sensor) that can detect the position in both the X-axis direction or the Y-axis direction and the Z-axis direction. In particular, the former may provide the encoder read head integrally with the Z read head.

In the above-described embodiment and modification, the malfunction (abnormality) of the encoder head includes, in addition to the mechanical failure, the head collapse, the shift of telecentricity thereof, and the like. In an encoder system of a type in which the head is disposed on the stage and the scale is disposed above the stage, an abnormality (malfunction) of the encoder head also includes the attachment of foreign matter (including, for example, liquid immersion fluid) to the head. In addition, the abnormality of the encoder head is included not only in the case where the position measurement is impossible but also in the case where the measurement accuracy exceeds the allowable value (the output (intensity) of the encoder head is out of the allowable range).

In the above embodiment, the case where the head units 62E and 62F are provided with seven Y heads, respectively, has been described, but the present invention is not limited to this, and the present invention is applicable to a plurality of mark detection systems (alignment systems AL1 and AL2 in the above embodiment)₁～AL2₄) Both sides are sufficient as long as there are Y heads, and the number is not critical. In brief, when the specific alignment marks on the wafer W are detected by the plurality of mark detecting systems, at least two Y heads 68, 67 are provided to face the pair of Y scales 39Y₁，39Y₂And (4) finishing. In the above embodiment, although the positions of the innermost two Y heads among the plurality of Y heads on both outer sides of the plurality of mark detection systems are different from those of the other Y heads, the present invention is not limited to this, and the Y position of any one Y head may be different. In brief, the Y position of any Y head may be different from the Y positions of other Y heads according to the space left. Alternatively, when there is sufficient space left on both outer sides of the plurality of mark detection systems, all the Y heads may be arranged at the same Y position.

The number of mark detection systems (alignment systems) is not limited to five, and two or more mark detection systems having different positions of the detection regions in the second direction (the X-axis direction in the above-described embodiment) are preferable, but the number is not particularly limited.

In the above-described embodiment, the lower surface of the nozzle unit 32 is substantially flush with the lower end surface of the front end optical element of the projection optical system PL, but the present invention is not limited thereto, and for example, the lower surface of the nozzle unit 32 may be disposed closer to the image plane (i.e., the wafer) of the projection optical system PL than the emission surface of the front end optical element. That is, the local immersion device 8 is not limited to the above-described structure, and those described in, for example, european patent application publication No. 1420298, U.S. patent application publication No. 2005/0231206, U.S. patent application publication No. 2005/0280791, and U.S. patent No. 6,952,253 can be used. As disclosed in U.S. patent application publication No. 2005/0248856, the optical path space on the object surface side of the front end optical element may be filled with a liquid in addition to the optical path on the image surface side of the front end optical element. Further, a film having lyophilic and/or dissolution preventing function may be formed on a part (including at least a contact surface with a liquid) or the whole of the surface of the front end optical element. Further, although quartz has high lyophilic properties to liquid and a dissolution preventing film is not required, it is preferable that at least fluorite is formed as a dissolution preventing film.

In the above embodiments, pure water (water) is used as the liquid, but the present invention is not limited to this. A safety liquid having a high transmittance of the illumination light IL and stable in chemical properties, such as a fluorine-containing inert liquid, may be used as the liquid. As the fluorine-containing inert liquid, for example, floriant (Fluorinert, trade name of 3M company in usa) can be used. The fluorine-containing inert liquid also has an excellent cooling effect. As the liquid, a liquid having a refractive index higher than that of pure water (refractive index of about 1.44), for example, a liquid having a refractive index of 1.5 or more can be used. Examples of such a liquid include isopropyl alcohol having a refractive index of about 1.50, a predetermined liquid having a C-H bond or an O-H bond such as glycerin having a refractive index of about 1.61, a predetermined liquid (organic solvent) such as hexane, heptane or decane, Decahydronaphthalene (Decahydronaphthalene) having a refractive index of about 1.60, and the like. Alternatively, any two or more of the above liquids may be mixed, or at least one of the above liquids may be added (mixed) to pure water. Alternatively, the liquid LQ may be prepared by adding (mixing) H to pure water⁺、Cs⁺、K⁺、Cl^-、SO4^2-、PO4^2-And the like bases and acids. Further, fine particles of Al oxide or the like may be added (mixed) to pure water. The liquid can transmit ArF excimer laser. Further, it is preferable that the liquid has a small absorption coefficient of light and a small temperature dependency, and is stable against a photosensitive material (or a protective film (top coat film), an antireflection film, or the like) applied to the projection optical system PL and/or the wafer surface. In addition, in F₂When laser is used as the light source, the perfluoropolyether Oil (Fomblin Oil) is selected. Further, as the liquid, a liquid having a refractive index higher than that of pure water, for example, a liquid having a refractive index of about 1.6 to 1.8 can be used. Supercritical fluids can also be used as liquids. The front end optical element of the projection optical system PL may be formed of a single crystal material of a fluorinated compound such as quartz (silicon dioxide), calcium fluoride (fluorite), barium fluoride, strontium fluoride, lithium fluoride, or sodium fluoride, or may be formed of a material having a higher refractive index (for example, 1.6 or more) than quartz or fluorite. Examples of the material having a refractive index of 1.6 or more include sapphire and germanium dioxide disclosed in the pamphlet of international publication No. 2005/059617, and potassium chloride (having a refractive index of about 1.75) disclosed in the pamphlet of international publication No. 2005/059618.

In the above embodiment, the recovered liquid may be reused, and in this case, a filter (for removing impurities from the recovered liquid) is preferably provided in the liquid recovery device, the recovery pipe, or the like.

In the above embodiment, the case where the exposure apparatus is a liquid immersion type exposure apparatus has been described, but the present invention is not limited thereto, and a dry type exposure apparatus which exposes the wafer W in a state where the liquid (water) does not permeate therethrough may be used.

In the above-described embodiments, the present invention has been described as being applied to a scanning exposure apparatus such as a step-and-scan system, but the present invention is not limited thereto, and can be applied to a still exposure apparatus such as a stepper. The present invention is also applicable to a reduction projection exposure apparatus, a proximity exposure apparatus, a mirror projection alignment exposure apparatus, and the like, which combine the shot region and the shot region by a step joining method. The present invention is also applicable to a multi-stage exposure apparatus including a plurality of wafer stages WST, as disclosed in, for example, U.S. Pat. No. 6,590,634, U.S. Pat. No. 5,969,441, and U.S. Pat. No. 6,208,407.

The projection optical system in the exposure apparatus according to the above embodiment may be not only a reduction system but also an equal magnification system or an enlargement system, and the projection optical system PL may be not only a refraction system but also a reflection system or a catadioptric system, and the projection image may be an inverted image or an erect image. Further, although the exposure region IA on which the illumination light IL is irradiated through the projection optical system PL is an on-axis region including the optical axis AX in the field of view of the projection optical system PL, for example, as in the case of the so-called on-line type catadioptric system disclosed in wo 2004/107011, the exposure region may be an off-axis region not including the optical axis AX, and the on-line type catadioptric system may have a plurality of reflection surfaces, and may have a single optical axis with an optical system (reflection system or catadioptric system) forming an intermediate image at least once provided in a part thereof. The illumination area and the exposure area are rectangular in shape, but the shape is not limited to this, and may be circular arc, trapezoid, parallelogram, or the like.

The light source of the exposure apparatus of the above embodiment is not limited to the ArF excimer laser light source, and a KrF excimer laser light source (output wavelength 248nm) and F can be used₂A pulse laser light source such as a laser beam (output wavelength: 157nm), an Ar2 laser beam (output wavelength: 126nm), or a Kr2 laser beam (output wavelength: 146nm), or an ultra-high pressure mercury lamp that emits bright rays such as g-rays (wavelength: 436nm) or i-rays (wavelength: 365 nm). Further, a harmonic generator of YAG laser or the like may be used. For example, a harmonic wave disclosed in pamphlet of international publication No. 1999/46835 (corresponding to U.S. patent No. 7,023,610) can be used, which is obtained by amplifying a single-wavelength laser beam in the infrared region or the visible region emitted from a DFB semiconductor laser or a fiber laser as a vacuum ultraviolet light by an optical fiber amplifier coated with erbium (or both erbium and ytterbium), and crystallizing the laser beam by nonlinear optical crystallizationConverting the wavelength to ultraviolet light.

In the above embodiment, the illumination light IL of the exposure apparatus is not limited to light having a wavelength of more than 100nm, and light having a wavelength of less than 100nm may be used. For example, in recent years, in order to expose a pattern of 70nm or less, an EUV exposure apparatus has been developed which generates EUV (extreme Ultra violet) light in a soft X-ray region (for example, a wavelength region of 5 to 15 nm) using an SOR or a plasma laser as a light source, and uses a total reflection reduction optical system and a reflection mask designed according to an exposure wavelength (for example, 13.5nm) thereof. The apparatus is constructed to scan and expose the mask and the wafer by using the arc illumination and the synchronous scanning, so that the present invention can be suitably applied to the apparatus. The present invention is also applicable to an exposure apparatus using charged particle beams such as electron beams or ion beams.

In the above embodiment, the light transmission mask (reticle) is used for forming a predetermined light shielding pattern (or phase pattern, or dimming pattern) on a substrate having light transmission properties, but an electronic mask (also referred to as a variable shape mask, an active mask, or an image generator, such as a DMD (Digital Micro-mirror Device) including a non-light emitting type image display element (spatial light modulator)) which forms a transmission pattern, a reflection pattern, or a light emitting pattern based on electronic data of a pattern to be exposed may be used instead of the mask, for example, as disclosed in U.S. Pat. No. 6,778,257.

The present invention is also applicable to an exposure apparatus (lithography system) that forms a pattern of lines with equal intervals on a wafer by forming interference fringes on the wafer, as disclosed in, for example, international publication No. 2001/035168.

Further, for example, the present invention can be applied to an exposure apparatus disclosed in, for example, U.S. Pat. No. 6,611,316, in which two reticle patterns are combined on a wafer through a projection optical system, and double exposure is performed on one irradiation region on the wafer substantially simultaneously by one scanning exposure.

The apparatus for forming a pattern on an object is not limited to the exposure apparatus (lithography system), and the present invention can be applied to an apparatus for forming a pattern on an object by an inkjet method, for example.

In the above embodiment, the object to be patterned (the object to be exposed to the energy beam) is not limited to a wafer, and may be another object such as a glass plate, a ceramic substrate, a film member, or a mask substrate.

The use of the exposure apparatus is not limited to exposure apparatuses for semiconductor manufacturing, and can be widely applied to, for example, manufacturing exposure apparatuses for liquid crystal for transferring a liquid crystal display element pattern onto a square glass plate, and manufacturing exposure apparatuses for organic EL, thin film magnetic heads, imaging elements (such as CCD), micromachines, DNA chips, and the like. In addition to the production of microdevices such as semiconductor devices, the present invention can be applied to an exposure apparatus for transferring a circuit pattern to a glass substrate, a silicon wafer, or the like in order to produce a reticle or a mask used in a light exposure apparatus, an EUV (extreme ultraviolet) exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, or the like.

Further, the disclosures of all publications, international pamphlets, U.S. patent application publications, and U.S. patent specifications relating to the exposure apparatus and the like cited in the above-described embodiments are incorporated as a part of the description of the present specification.

An electronic device such as a semiconductor device is manufactured by the steps of: a step of performing function and performance design of an element, a step of fabricating a wafer from a silicon material, a photolithography step of transferring a pattern of a reticle onto a wafer by an exposure apparatus (pattern forming apparatus) of the above-described embodiment, a development step of developing the exposed wafer, an etching step of removing an exposed member except for a photo resist residual portion by etching, a photo resist removal step of removing an unnecessary photo resist after the etching is finished, an element assembling step (including a dicing step, a bonding step, a packaging step), an inspection step, and the like. In this case, since the exposure method is performed using the exposure apparatus of the above embodiment in the lithography step to form a device pattern on a wafer, a device having a high body density can be manufactured with good productivity.

As described above, the mobile body apparatus according to the present invention is suitable for managing the position of a mobile body moving along a predetermined plane in the predetermined plane. The pattern forming apparatus of the present invention is suitable for forming a pattern on an object such as a wafer. The exposure apparatus and the device manufacturing method according to the present invention are suitable for manufacturing an electronic device microdevice such as a semiconductor device.

Claims (29)

1. A mobile body apparatus including a mobile body that substantially moves along a predetermined plane, comprising:

a scale arranged on one of the movable body and an outer portion of the movable body, the scale having a grating section which has a first direction in a plane parallel to the predetermined plane as a longitudinal direction and has a predetermined width in a second direction orthogonal to the first direction; and

a measuring device that measures positional information of the movable body in a periodic direction of the grating section at a plurality of measuring points arranged on the scale;

the arrangement of the plurality of measurement points is set so that n points (where n is an integer of 2 or more) or more of the plurality of measurement points are within the predetermined width on the scale, and n +1 points or more of the plurality of measurement points are within the predetermined width on the scale when the movable body is at the predetermined position.

2. The movable body apparatus according to claim 1 wherein the scale is provided on a surface of the movable body which is substantially parallel to the predetermined plane.

3. The movable body apparatus according to claim 2 wherein a pair of the scales separated in the second direction is provided to the movable body;

the arrangement of the measurement points is set such that when the movable body is located within a predetermined range within the predetermined plane, n or more measurement points are located on at least one of the pair of scales as needed.

4. The movable body apparatus according to claim 2 wherein the movable body is further provided with a pair of other scales whose respective longitudinal directions are directed to the second direction and are separated in the first direction;

the arrangement of the measurement points is set such that when the movable body is located within a predetermined range within the predetermined plane, n or more measurement points are located on at least one of the pair of other scales as needed.

5. The movable body apparatus according to claim 1 or 2 further comprising a control device that performs position control of the movable body preferentially using first measurement information including measurement information at a first measurement point, among the measurement points at least n points located within the predetermined width of the scale or the measurement points at least n +1 points located within the predetermined width of the scale when the movable body is at the predetermined position;

the control device switches, when an abnormality occurs in measurement information at a measurement point located within the predetermined width of the scale, measurement information preferentially used for position control of the movable body to second measurement information including measurement information at a second measurement point different from the first measurement point.

6. The movable body apparatus according to claim 5 wherein the control means switches measurement information used for position control of the movable body to the second measurement information when an abnormality occurs in the measurement information at the first measurement point.

7. The movable body apparatus according to claim 5 or 6 wherein the first measurement information and the second measurement information respectively include measurement information at a plurality of measurement points.

8. The movable body apparatus according to claim 5 or 6 wherein the first measurement information and the second measurement information each include measurement information at one measurement point.

9. The movable body apparatus according to any one of claims 5 to 8 wherein the measurement apparatus has a plurality of heads that irradiate measurement beams to measurement points;

the control device performs the switching when the abnormality of the measurement information occurs due to a malfunction of the head.

10. The movable body apparatus according to claim 1 or 2 wherein the measurement apparatus has a plurality of heads that irradiate measurement beams to measurement points, and the plurality of heads irradiate the measurement beams to different measurement points.

11. The movable body apparatus according to claim 1 or 2 wherein the measurement points are arranged at substantially equal intervals in a direction orthogonal to a longitudinal direction of the scale at intervals equal to or less than half a predetermined width of the scale.

12. The movable body apparatus according to claim 1 or 2 wherein the measurement device has first and second heads that irradiate measurement beams on the same measurement point, and an irradiation region of the measurement beam irradiated from the first head and an irradiation region of the measurement beam irradiated from the second head are close to each other without overlapping.

13. A mobile body apparatus including a mobile body that substantially moves along a predetermined plane, comprising:

a scale arranged on one of the movable body and an outer portion of the movable body, the scale having a grating section which has a first direction in a plane parallel to the predetermined plane as a longitudinal direction and has a predetermined width in a second direction orthogonal to the first direction;

a measuring device that measures positional information of the movable body in a periodic direction of the grating section at a plurality of measuring points arranged on the scale;

the measuring apparatus includes a plurality of head sets including a first head for irradiating a first measuring point with measuring light and a second head for irradiating the first measuring point or its vicinity with measuring light.

14. The movable body apparatus according to claim 13 wherein the scale is provided on a surface of the movable body which is substantially parallel to the predetermined plane.

15. The movable body apparatus according to claim 13 or 14 wherein measurement points on which the first head and the second head included in the head group irradiate measurement beams are arranged at substantially equal intervals every predetermined width.

16. The movable body apparatus according to any one of claims 13 to 15 wherein at least a part of a measurement region where the measurement beam is irradiated by the first head and a part of a measurement region where the measurement beam is irradiated by the second head overlap each other in the measurement apparatus.

17. The movable body apparatus according to any one of claims 13 to 16 further comprising a control device that controls the position of the movable body by preferentially using the measurement information generated by the first head, and switches the measurement information preferentially used from the measurement information generated by the first head to the measurement information generated by the second head when an abnormality occurs in the measurement information generated by the first head.

18. The movable body apparatus according to claim 17 wherein the control device performs the switching when an abnormality in the measurement information occurs due to a malfunction of the head.

19. A movable body apparatus including a movable body substantially moving along a predetermined plane, characterized in that:

the measurement device is provided for measuring position information of the movable body in one degree of freedom direction in the predetermined plane at a plurality of measurement points arranged in the movement range of the movable body;

the measurement device includes a plurality of heads that generate measurement information by irradiating measurement light onto at least one of the plurality of measurement points when the movable body is located at a predetermined position.

20. The movable body apparatus according to claim 19 wherein the head is disposed on the movable body.

21. The movable body apparatus according to claim 19 wherein the movable body has a scale that reflects the measurement light irradiated from the head.

22. The movable body apparatus according to any one of claims 19 to 21 wherein the plurality of heads includes a first head and a second head that irradiate a measurement beam to one and the same measurement point among the plurality of measurement points when the movable body is located at the predetermined position, and at the measurement point, an irradiation region of the measurement beam irradiated from the first head overlaps at least a part of an irradiation region of the measurement beam irradiated from the second head.

23. The movable body apparatus according to any one of claims 19 to 21 wherein the plurality of heads includes a first head and a second head that irradiate a measurement beam to one and the same measurement point of the plurality of measurement points when the movable body is at the predetermined position, and in the measurement point, an irradiation region of the measurement beam irradiated from the first head and an irradiation region of the measurement beam irradiated from the second head are close to each other without overlapping.

24. The movable body apparatus according to claim 22 or 23 further comprising a control device that controls a position of the movable body by preferentially using measurement information generated by a first head among the plurality of heads that irradiate the measurement beam to the same measurement point, and switches the measurement information preferentially used from the measurement information generated by the first head to measurement information generated by a second head among the plurality of heads when an abnormality occurs in the measurement information generated by the first head.

25. The movable body apparatus according to claim 24 wherein the control device performs the switching when an abnormality in the measurement information occurs due to a malfunction of the head.

26. A pattern forming apparatus for forming a pattern on an object, comprising:

a patterning device configured to form a pattern on the object; and

the movable body apparatus according to any one of claims 1 to 25 for mounting the object on the movable body.

27. The patterning device of claim 26, wherein the object has a sensitive layer, and the patterning device forms the pattern on the object by exposing the sensitive layer.

28. An exposure apparatus for forming a pattern on an object by irradiating an energy beam, comprising:

a patterning device for irradiating the object with the energy beam;

the movable body apparatus according to any one of claims 1 to 25 for mounting the object on the movable body; and

and a driving device for driving the movable body so as to move the object relative to the energy beam.

29. A device manufacturing method using the exposure apparatus according to claim 28.