JP2002343853A - Substrate holding apparatus, exposure system and device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deformation to be generated in the free end part near the outer edge part of a wafer. SOLUTION: A holder body 70 has a plurality of pin parts 32 and a rim part 28, and among these pin parts at least the pin parts positioned near the rim part are arranged so that their spacing is smaller than that of the pin parts positioned in the other parts. Thus, the local ratio of contact between the pin parts in the neighborhood of the rim part and the wafer can approach the local ratio of contact between the rim part and the wafer. Therefore, even in the case of polishing work is carried out by using a polishing apparatus, etc., in the stage of manufacturing the holder body to improve the flatness of the surface to be brought in contact with the wafer, the difference of the contact pressure applied on the rim part and the pin parts in the neighborhood of the rim part from the polishing part (working part) can be reduced so that the level difference between the respective parts formed during the work can be minimized. The deformation (inclination angle) to be generated in the free end part near the outer edge part of the wafer can be reduced when the wafer is held by such a holder body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate holding apparatus, an exposure apparatus, and a device manufacturing method, and more particularly, to a substrate holding apparatus for holding a flat substrate, an exposure apparatus having the substrate holding apparatus, and an exposure apparatus. The present invention relates to a device manufacturing method for performing exposure using an exposure apparatus.

[0002]

2. Description of the Related Art Conventionally, in a lithography process for manufacturing a semiconductor device, a liquid crystal display device, or the like, a pattern formed on a mask or a reticle (hereinafter, collectively referred to as a “reticle”) is exposed to a resist or the like via a projection optical system. There is used an exposure apparatus that transfers an image onto a substrate such as a wafer or a glass plate (hereinafter, collectively referred to as a “wafer”) on which is coated. In recent years, with the increase in the degree of integration of semiconductor elements, a step-and-repeat type reduction projection exposure apparatus (so-called stepper) or a step-and-scan type scanning projection exposure apparatus (an so-called step-and-scan type) which is an improvement on this stepper has been developed. Sequentially moving projection exposure apparatuses such as a scanning stepper are mainly used.

In such a projection exposure apparatus, a wafer stage movable in a two-dimensional plane is provided.
The wafer is held by vacuum suction or electrostatic suction by a wafer holder fixed on the wafer stage.

One example of a conventional wafer holder is shown in FIG.
(A) shows a plan view. The wafer holder 25 'in FIG. 11A has a disc-shaped base member 26'
A large number of pin portions 32 ′ and a large number of pin portions 3, which are arranged at equal intervals on the upper surface of the base member 26 ′ (surface on the front side of the drawing).
An annular convex portion (hereinafter, generally referred to as a “rim portion”) 28 ′ surrounding 2 ′. And many pin parts 3
The wafer is supported from below by the 2 'and the rim portion 28', and the wafer is suction-held by vacuum suction or the like. The wafer holder 25 'shown in FIG.
A wafer holder similar to that described in, for example,
No. 8, for example.

In the above-described conventional wafer holder, when the wafer is supported by the pins by, for example, vacuum suction or the like, the amount of deformation of the pins at the unsupported positions other than the pins is controlled to fall within a predetermined allowable range. The arrangement, spacing, etc., have been determined.

Further, in order to ensure the flatness of the wafer (substrate), it is desirable that the contact portion of the wafer holder with the wafer be as coplanar as possible. The upper surface is precisely polished using a polishing device.

[0007]

In the wafer holder 25 'shown in FIG. 11 (A) or the wafer holder disclosed in the above-mentioned publication, the above-described operation is performed in order to prevent foreign matter from being pinched between the pin portion and the wafer as much as possible. The contact ratio of the pin portion has been set so as to minimize the contact ratio as long as the deformation amount is within an allowable range. On the other hand, the rim has a certain width or more due to the limit of the processing technology. Therefore, when the contact ratio of the pin portion determined based on the allowable deformation amount described above is small, the ratio of the contact area of the rim portion to the entire contact ratio increases.

Further, when the method of determining the contact ratio of a pin portion according to the above-described conventional technique is employed, at the time of polishing at the manufacturing stage, the pin portion is moved per unit area with respect to the polishing portion (processed portion) of the polishing apparatus. The contact pressure is higher than that of the rim. In addition, while the pin portion has a sufficient amount of abrasive grains used during polishing, the rim portion tends to have an insufficient amount of abrasive particles. For this reason, the processing speed of the pin portion is higher than the processing speed of the rim portion. Due to this difference in processing speed, FIG. 11B is an end view showing a vertical cross section of the wafer holder 25 ′ of FIG. 11A holding the wafer W by suction between the pin portion and the rim portion. As described above, the processing step Δa is generated between the rim portion 28 ′ and the pin portion 32 ′. For this reason, the free end near the outer edge of the wafer W is deformed by the inclination angle θ as shown in FIG. 11B, which causes defocusing at the time of exposure. In particular, recently, since there is a tendency to obtain chips also from the vicinity of the outer edge of the wafer, the deformation of the outer edge of the wafer as described above may cause a reduction in the yield of devices as final products.

The present invention has been made under such circumstances, and a first object of the present invention is to provide a substrate holding device capable of minimizing a processing step generated on a contact surface with a substrate during polishing. It is in.

A second object of the present invention is to provide an exposure apparatus capable of improving exposure accuracy.

A third object of the present invention is to provide a device manufacturing method capable of improving device productivity.

[0012]

According to a first aspect of the present invention, there is provided a substrate holding apparatus for holding a flat substrate (W), wherein each end portion is substantially flush with a predetermined area. A plurality of protruding first support portions (32) for supporting the substrate disposed so as to be positioned above, and disposed outside the region, surrounding at least most of the outside of the region, Along with the first support, a second support (2) supporting the substrate while maintaining its flatness substantially.
8), wherein at least a first support portion of the plurality of first support portions located near the second support portion is a first support portion located at another portion. The substrate holding device is characterized in that the substrate holding device is arranged at a closer interval than that of the substrate holding device.

According to this, the flat substrate is supported by the plurality of projection-like first support portions and the second support portions of the holding device main body while maintaining the flatness thereof substantially. In this case, among the plurality of first support portions, at least the first support portions located near the second support portion are arranged at a closer interval than the first support portions located at other portions. That is, the local contact ratio (area ratio of the contact surface) between the second support portion and the substrate is at least the local contact ratio (area ratio of the contact surface) between the first support portion and the substrate near the second support portion. ) Can be approached. Therefore, for example, in a manufacturing stage of the substrate holding device, when polishing is performed using a polishing device or the like to obtain flatness on the substrate contact surface side of the substrate holding device, the second support portion and the vicinity of the second support portion are polished. It is possible to reduce the difference in the contact pressure from the polishing portion (processed portion) applied to each portion of the first support portion, thereby making it possible to minimize the processing step generated between the two during the polishing process. That is, the processing step generated on the contact surface of the substrate holding device (main body of the holding device) with the substrate can be minimized. As a result, it is possible to reduce the deformation (tilt angle) generated at the free end near the outer edge of the substrate.

In this case, the plurality of first supporting portions are
For example, the interval between the adjacent first support portions may be arranged so as to change stepwise in the vicinity of the second support portion, in the vicinity of the center of the region, and in a portion therebetween. As in the substrate holding device according to claim 2, the plurality of first support portions are arranged such that an interval between adjacent first support portions is the second support portion.
The arrangement may be such that it becomes wider as the distance from the support part increases.

In each of the substrate holding devices according to the first and second aspects, as in the substrate holding device according to the third aspect, the plurality of first supporting portions correspond to a center position of the substrate. It may be arranged on a plurality of concentric circles centered on a reference point on the main body.

In each of the substrate holding devices according to the first to third aspects, as in the substrate holding device according to the fourth aspect, the tip portions of the plurality of first support portions and the upper end portions of the second support portions. Suction mechanism (38)
A to 38C, 40, 46A, V1).

In this case, as the suction mechanism, an electrostatic suction mechanism or the like may be employed. However, as in the substrate holding device according to the fifth aspect, the second support section is provided with the plurality of first support sections. In a case where the suction mechanism has an annular inner peripheral surface that completely surrounds the area where the portion is disposed, the suction mechanism is configured such that the substrate is supported by the holding device main body, and the substrate and the holding device main body use the suction mechanism. A vacuum suction mechanism (38) for evacuating a space formed inside the inner peripheral surface of the second support portion.
A to 38C, 40, 46A, V1).

In this case, as in the substrate holding device according to the sixth aspect, the second support portion may include an annular convex portion (228) arranged concentrically and an annular concave portion on the outer peripheral side of the annular convex portion (228). 134), and the vacuum suction mechanism can also bring the annular concave portion into a vacuum state.

In this case, as in the substrate holding apparatus according to claim 7, the annular convex portion is provided concentrically with two or more concentric circles, and the vacuum suction mechanism is provided with an adjacent annular convex portion (2).
8a, 28b) The space (51) between them can also be in a vacuum state.

In each of the substrate holding devices according to the first to seventh aspects, as in the substrate holding device according to the eighth aspect, the contact area between the second supporting portion and the substrate is equal to the plurality of first holding portions.
The contact area may be set to 20% or less of the total contact area between the support and the second support and the substrate.

In this case, as in the substrate holding device according to claim 9, the plurality of first support portions occupy the entire area of the surface of the substrate on the side supported by the first and second support portions. The ratio of the contact area between the second support and the substrate may be set to 3% or less.

According to a tenth aspect of the present invention, there is provided a substrate holding apparatus for holding a flat plate-shaped substrate (W), such that respective end portions are located on substantially the same plane within a region of a predetermined area. A plurality of protruding first support portions (32) for supporting the disposed substrate; and a plurality of first support portions disposed outside the region, surrounding at least a large portion of the outside of the region, and together with the plurality of first support portions, A holding device main body (70) having a second support portion (28) for supporting the substrate while maintaining its flatness substantially, wherein a contact area between the second support portion and the substrate is the plurality of A substrate holding device, wherein a total contact area between the first support portion and the second support portion and the substrate is set to 20% or less.

According to this, the flat substrate is supported by the plurality of projection-like first support portions and the second support portions of the holding device main body while maintaining the flatness thereof substantially. In this case, the contact area between the second support portion and the substrate is two times the total contact area between the plurality of first support portions and the second support portion and the substrate.
It is set to be 0% or less. In this regard, the inventor has determined that an area where the plurality of first support portions and the substrate are in contact,
The area where the second support part and the substrate are in contact, and the contact area between the plurality of first support parts and the second support part and the substrate (total contact area)
Focusing on the relationship between these areas and machining steps,
We conducted various simulations and experiments, and conducted extensive research. As a result, it is sufficiently practical to set the contact area between the second support and the substrate to 20% or less of the contact area (total contact area) between the second support and the plurality of first supports and the substrate. Was obtained.

That is, by setting the ratio of the contact area between the second support portion and the substrate to the total contact area to 20% or less, the processing step between the support portions in the polishing process at the manufacturing stage can be minimized. This makes it possible to reduce the deformation (tilt angle) generated at the free end near the outer edge of the substrate.

According to the present invention, the mask (R)
An exposure apparatus for transferring a pattern formed on a substrate (W) via a projection optical system (PL), comprising:
0. The substrate holding device according to any one of items 0 to 70.
A focus position detection system (60a, 60b) for detecting a position of the surface of the substrate held by the substrate holding device with respect to an optical axis direction of the projection optical system and an inclination amount with respect to a plane orthogonal to the optical axis direction. A driving device (19, 20, 24) for driving the substrate holding device in at least one of the optical axis direction and a tilt direction with respect to a plane orthogonal to the optical axis direction based on a detection result of the focal position detection system. When;
An exposure apparatus comprising:

According to this, since the substrate is held by the substrate holding device according to any one of claims 1 to 10, the substrate has a certain degree of flatness including a free end near the outer edge thereof. , That is, without extreme irregularities. Then, the position of the substrate held by the substrate holding device in the optical axis direction and the amount of inclination with respect to a plane perpendicular to the optical axis direction are detected by a focus position detection system, and based on the detection result, the driving device The holding device is driven in at least one of the optical axis direction and a tilt direction with respect to a plane orthogonal to the optical axis direction. Thus, even if a gentle inclination exists on the substrate, the inclination of the entire substrate and the position in the optical axis direction are adjusted via the substrate holding device, so that the exposure area ( It is possible to transfer the pattern formed on the mask onto the substrate in a state where the areas to be exposed are matched. Therefore,
It is possible to perform high-precision exposure with almost no deterioration in pattern transfer accuracy due to defocus.

According to a twelfth aspect of the present invention, there is provided a device manufacturing method including a lithography step, wherein in the lithography step, exposure is performed using the exposure apparatus according to the eleventh aspect.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS << First Embodiment >> A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a schematic configuration of an exposure apparatus 100 according to the first embodiment. This exposure apparatus 100
Is a step-and-scan type projection exposure apparatus. The exposure apparatus 100 includes an illumination system 10, a reticle stage RST for holding a reticle R as a mask, a projection optical system PL, a stage device 50 on which a wafer W as a substrate is mounted, and a control system therefor. .

The illumination system 10 is, for example, disclosed in
As disclosed in Japanese Patent No. 12433 and the like,
Fly-eye lens as optical integrator or
Rod integrator (internal reflection type integrator) etc.
Illuminating uniformity optical system, including relay lens, variable ND filter
Ruta, reticle blind, and dichroic mirror
(Both are not shown). This light
In the light system 10, on the reticle R on which a circuit pattern and the like are drawn
Illumination area defined by the reticle blind
The area is almost completely irradiated by the illumination light IL as an energy beam.
Illuminate with uniform illuminance. Here, as the illumination light IL,
Far purple such as KrF excimer laser light (wavelength 248 nm)
External light, ArF excimer laser light (wavelength 193 nm),
Or F _TwoVacuum ultraviolet light such as laser light (wavelength 157 nm)
Light or the like is used. Ultra-high pressure mercury lamp as illumination light IL
Use ultraviolet emission lines (g-line, i-line, etc.) from the pump
Is also possible.

On the reticle stage RST, a reticle R is fixed, for example, by vacuum suction. The reticle stage RST is perpendicular to an optical axis of the illumination system 10 (coincident with an optical axis AX of a projection optical system PL described later) for positioning the reticle R by a reticle stage driving unit (not shown) including, for example, a linear motor. In addition to being capable of minute driving in the XY plane, it can be driven at a scanning speed designated in a predetermined scanning direction (here, the X-axis direction).

The position of the reticle stage RST in the stage movement plane is determined by a reticle laser interferometer (hereinafter referred to as “reticle interferometer”) 16 via a movable mirror 15.
For example, it is always detected with a resolution of about 0.5 to 1 nm.
Position information of the reticle stage RST from the reticle interferometer 16 is supplied to the stage controller 19 and the main controller 20 via the stage controller 19. In the stage control device 19, the reticle stage RS
The reticle stage RST is driven and controlled via a reticle stage driving unit (not shown) based on the position information of T.

The projection optical system PL is disposed below the reticle stage RST in FIG. 1, and the direction of the optical axis AX is the Z-axis direction. As the projection optical system PL, for example, a refracting optical system having a predetermined reduction magnification (for example, 1/5 or 1/4) that is telecentric on both sides is used. Therefore, when the illumination area of the reticle R is illuminated by the illumination light IL from the illumination system 10, the illumination light IL passing through the reticle R causes the circuit of the reticle R in the illumination area to pass through the projection optical system PL. A reduced image (partially inverted image) of the pattern is formed on wafer W having a surface coated with a resist (photosensitive agent).

The stage device 50 includes a wafer stage WST, a holder main body 70 as a holding device main body provided on the wafer stage WST, a wafer stage driving section 24 for driving the wafer stage WST and the holder main body 70, and the like. ing. Wafer stage WST
The XY stage 31 is disposed on a base (not shown) below the projection optical system PL in FIG. 1 and is driven in the XY directions by a linear motor or the like (not shown) constituting the wafer stage drive unit 24; The Z · not shown, which is mounted on the stage 31 and constitutes the wafer stage driving unit 24,
The tilt drive mechanism is used to move the Z-tilt stage 30 that is minutely driven in the Z-axis direction and the tilt direction (the rotation direction around the X-axis (θx direction) and the rotation direction around the Y-axis (θy direction)) with respect to the XY plane. Have. The holder main body 70 for holding the wafer W is mounted on the Z-tilt stage 30.

As shown in the plan view of FIG. 2, the holder main body 70 has a circular plate-like base portion 26,
A plurality of projections as a plurality of first support portions provided at predetermined intervals in an area of a predetermined area in a central portion excluding an annular area of a predetermined width near an outer peripheral portion of an upper surface (a surface on the front side of the paper surface in FIG. , An annular convex portion (hereinafter, referred to as a “rim portion”) serving as a second support portion provided in the vicinity of the outer peripheral edge in a state surrounding the region where the plurality of pin portions 32 are arranged. 28).

The holder body 70 is made of a material having a low expansion coefficient, for example, ceramics, and is formed by etching the surface of a material such as a disc-shaped ceramic as a whole.
A circular plate-shaped base 26 constituting a bottom surface, a rim 28 protruding from the upper surface of the base 26 and a plurality of pins 32 are integrally formed.

FIG. 3 is an enlarged view of the holder body 70 and specifically shows the arrangement of the pin portion 32 and the rim portion 28. As can be seen from FIG. 3, the outer diameter of the rim portion 28 is set slightly smaller than the outer diameter of the wafer W (shown by a two-dot chain line (imaginary line)), for example, about 1 to 2 mm smaller.
The upper surface is processed horizontally and flatly so that no gap is formed between the upper surface and the rear surface of the wafer W when the wafer W is mounted.

Each of the pin portions 32 has a protruding shape such that each of its tip portions is located substantially on the same plane as the rim portion 28. These pin portions 32 are arranged along multiple concentric circles centered on a reference point on the base portion 26, here a center point. In the case of the present embodiment, the interval between the adjacent concentric circles is set to be narrower near the rim portion 28 and gradually narrower as the distance from the rim portion 28 approaches the center point. That is, the interval between the adjacent pin portions 32 is different from that of the rim portion 28.
It is arranged so that it becomes wider as it moves away from it.

For this reason, the pin portion 32 located near the rim portion 28 has a local contact ratio (more specifically, a contact portion between the pin portion 32 occupying a unit area of a predetermined area and the back surface of the wafer W). Surface area ratio) as close as possible to the local contact ratio of the rim portion 28 (more specifically, the ratio of the area of the contact surface between the rim portion 28 and the back surface of the wafer W occupying the unit area). It is densely arranged. Also, the holder body 7
0, the total area of the contact surface between the upper surface of the rim portion 28 and the back surface of the wafer W is 20% or less of the total area of the contact surface between the back surface of the wafer W and the rim portion 28 and the pin portion 32. The number of pins 32, the area of the tip surface (upper surface), the shape of the upper surface of the rim portion 28, and the like are set. In addition,
The arrangement of the pins and the like will be further described later.

The holder body 70 thus constructed
Then, in the manufacturing stage, as described above, the base 2
6, after integrally forming the pin portion 32 and the rim portion 28, a polishing device, abrasive grains, and the like are provided on the upper end surfaces of the plurality of pin portions 28 and the upper surface of the rim portion 28, which are finally contact surfaces with the wafer W. The polishing process is performed by using. As a result, the upper end surfaces of the plurality of pin portions 28 and the upper surface of the rim portion 28 are located substantially on the same plane.

Returning to FIG. 2, in the vicinity of the central portion of the base portion 26, three through holes (not shown in FIG. 2, but shown in FIG. In FIG. 1, only one through hole 84 is shown).
It is formed in a state where it does not mechanically interfere with. Vertically moving pins (center-up) 34a, 34b, 34c each having a columnar shape are inserted into each of these through holes, and these three center-ups 34a to 34c are shown in FIG.
Via the vertical movement mechanism (not shown) constituting the wafer stage drive section 24 of the above-described manner, the wafer stage drive section 24 can be simultaneously moved up and down by the same amount in the vertical direction (Z-axis direction). During wafer loading and wafer unloading, which will be described later, the center-ups 34a to 34c are driven by the vertical movement mechanism, thereby supporting the wafer W from below or supporting the wafer W by the three center-ups 34a to 34c. Can be moved up and down.

In this embodiment, three vertically moving pins are used when loading and unloading a wafer. However, loading and unloading of a wafer can be performed without using vertically moving pins. For example, a pair of grooves formed in the surface of the Z tilt stage 30 are formed on the surface of the Z tilt stage 30 by forming a pair of grooves separated in the X-axis direction by the same degree as the diameter of the rim 28 and extending in the Y-axis direction. A total of three notches for claw insertion are formed at positions facing the groove (one at the position facing one groove and two at the position facing the other groove). Then, the holder body (wafer holder) and the transfer arm for loading or unloading are relatively moved in the Y-axis direction, so that the lower end of the transfer arm is separated in the X-axis direction by the same degree as the diameter of the rim portion 28. By inserting or removing the three claw portions provided in the pair of groove portions from the groove portions, and by relatively moving the holder body and the transfer arm in the Z-axis direction,
The loading and unloading of the wafer may be performed by performing an operation of inserting each of the three claw portions into the groove portion through the corresponding notch or detaching the three claw portions from the groove portion and the holder main body.

As shown in FIG. 2, a plurality of air supply / exhaust ports 36 are provided on the upper surface of the base portion 26 in a radial direction from the vicinity of the center of the upper surface of the base portion 26 (interval of a central angle of about 120 °). (Three radial directions). These supply / exhaust ports 36 are also formed at positions that do not mechanically interfere with the pin portions 32. Supply / exhaust port 3
6 is a supply / exhaust passage 38A formed inside the base portion 26,
The supply / exhaust branch pipe 4 that constitutes a supply / exhaust mechanism 80 described later connected to the outer peripheral surface of the base portion 26 via 38B and 38C.
0a, 40b, and 40c.

The supply / exhaust passages 38A to 38C are shown in FIG. 4, which is a sectional view taken along line AA of FIG.
A will be briefly described as a representative. The supply / exhaust passage 38A has a trunk passage 88A formed along the radial direction (X-axis direction) from the outer peripheral surface of the base portion 26 to the vicinity of the center of the base portion 26, and a predetermined distance from the trunk passage 88A in the radial direction. separating the (here six) more that is branched into each + Z direction is a path consisting of the branch passage 86A ₁ ~86A ₆ Tokyo of. In this case, each open end of the upper end of the branch passage 86A ₁ ~86A ₆ has a supply and exhaust port 36 as described above. The remaining two supply / exhaust passages 38B and 38C are also connected to the supply / exhaust passage 3
It has the same configuration as 8A.

As shown in FIG. 2, the wafer W mounted on the holder main body 70 and supported from below by the plurality of pins 32 and the rim 28 is placed on the holder main body 70 configured as described above. , The plurality of pins 32 and the rim 2
8 is connected to a supply / exhaust mechanism 80 including a vacuum suction mechanism as a suction mechanism for sucking and holding each upper end surface (upper end).

The supply / exhaust mechanism 80 includes a first vacuum pump 4
6A, the vacuum chamber 46Ba and the second vacuum pump 46Bb, and the air supply device 46C, and the first vacuum pump 46
A, a vacuum chamber 46Ba, a second vacuum pump 46Bb, and a supply / exhaust pipe 40 for connecting an air supply device 46C to the supply / exhaust passages 38A to 38C, respectively.

The supply / exhaust pipe 40 is provided with a supply / exhaust main pipe 40d.
And the aforementioned supply / exhaust branch pipes 40a, 40b, 40c branched into three from one end of the supply / exhaust main pipe 40d, and the first exhaust branch pipe 4 branched into three from the other end of the supply / exhaust main pipe 40d.
0e, a second exhaust branch pipe 40f, and an air supply branch pipe 40g.

The supply / exhaust main pipe 40 of the first exhaust branch pipe 40e
The first vacuum pump 46A is connected to an end opposite to the end d from the supply / exhaust main pipe 40d of the second exhaust branch pipe 40f via an electromagnetic valve (electromagnetic valve) V1. One end of the vacuum chamber 46Ba is connected to the end via a solenoid valve V2. A second vacuum pump 46Bb is connected to the other side of the vacuum chamber 46Ba. The air supply branch pipe 4
An air supply device 46C is connected via an electromagnetic valve V3 to an end opposite to the 0g supply / exhaust main pipe 40d.

Although not shown, a barometer for measuring the pressure inside the supply / exhaust pipe 40 is connected to a part of the supply / exhaust main pipe 40d. The value measured by the barometer is supplied to the main controller 20 shown in FIG.
0 controls the opening and closing of each of the solenoid valves V1 to V3 and the operation of the vacuum pumps 46A and 46Bb and the air supply device 46C based on the measurement value of the barometer and the control information for loading and unloading the wafer. It has become. Note that these operations will be described in further detail later.

Returning to FIG. 1, the XY stage 31 can not only move in the scanning direction (X-axis direction) but also position a plurality of shot areas on the wafer W in an exposure area conjugate with the illumination area. In addition, it is configured to be movable also in a non-scanning direction (Y-axis direction) orthogonal to the scanning direction, and performs an operation of scanning (scanning) exposure of each shot area on the wafer W, and an acceleration for exposure of the next shot. A step-and-scan operation of repeating the operation of moving to the start position is performed.

The position of the wafer stage WST in the XY plane (including the rotation around the Z axis (θz rotation)) is determined via the movable mirror 17 provided on the upper surface of the Z-tilt stage 30 by the wafer laser interferometer system. 18, is always detected with a resolution of, for example, about 0.5 to 1 nm. Here, actually, as shown in FIG. 2, for example, on the Z-tilt stage 30, an X movable mirror 17X having a reflecting surface orthogonal to the scanning direction (X-axis direction) and a non-scanning direction (Y-axis And a Y-moving mirror 17Y having a reflecting surface orthogonal to the direction of the wafer laser interferometer system 1
8 also irradiates the X moving mirror 17X vertically with the interferometer beam.
An interferometer and a Y interferometer for irradiating the Y moving mirror 17Y with an interferometer beam vertically are provided. In FIG. 1, these are typically the moving mirror 17, the wafer laser interferometer system 18 and the like.
It is shown as At least one of the X interferometer and the Y interferometer of the wafer laser interferometer system 18 is a multi-axis interferometer having a plurality of measurement axes, and the interferometer allows the wafer stage WST (more precisely, the Z-tilt The θz rotation (yaw) of the stage 30) is also measured. The X and Y movable mirrors 17X and 17Y may be formed by forming a reflection surface on a member different from the holder main body 70 and fixed to the holder main body 70, or a reflection surface may be provided on an end surface (side surface) of the holder main body 70. It may be formed.

The position information (or speed information) of wafer stage WST is supplied to stage controller 19 and main controller 20 via the same. In the stage control device 19, the wafer stage WS
Based on the position information (or speed information) of T, the wafer stage WST is controlled via the wafer stage drive unit 24.

As shown in FIG. 1, the exposure apparatus 100 of this embodiment has a light source whose ON / OFF is controlled by the main controller 20, and a large number of pinholes are directed toward the image forming plane of the projection optical system PL. Alternatively, an irradiation system 60a that irradiates an image forming light beam for forming an image of a slit from an oblique direction with respect to the optical axis AX, and a light receiving system 60b that receives the reflected light beam of the image forming light beam on the wafer W surface. A focus position detection system comprising a multi-point focus position detection system of an oblique incidence type comprising: Note that the focus position detection system (60a, 6
The detailed configuration of the multi-point focal position detection system similar to 0b) is disclosed in, for example, JP-A-6-283403.

Under instructions from the main controller 20, the stage controller 19 controls the light receiving system 60b during scanning exposure, which will be described later.
The Z-tilt stage 30 and the holder body 70 are moved in the Z-axis direction via the wafer stage driving unit 24 so that the defocus becomes zero based on a defocus signal (a defocus signal), for example, an S-curve signal. And controlling the tilt to two-dimensional points (that is, rotation in the θx and θy directions), that is, controlling the movement of the Z tilt stage 30 and the holder main body 70 using the multipoint focal position detection system (60a, 60b). As a result, auto-focusing (auto-focusing) and auto-leveling for substantially matching the image plane of the projection optical system PL with the surface of the wafer W within the irradiation area of the illumination light IL (the image formation relationship with the illumination area) are executed. I do. That is, in the present embodiment, the main controller 20 and the stage controller 19
And a drive device for driving the holder main body 70 in the optical axis AX direction and in a tilt direction with respect to a plane orthogonal to the optical axis based on the detection result of the focus position detection system (60a, 60b) by the wafer stage drive unit 24. ing.

Next, the operation of the exposure apparatus of the present embodiment when loading and unloading the wafer W onto the holder main body 70 will be described.

When loading the wafer W, the solenoid valves V1 to V3 in FIG. 2 are all closed, and the air supply and exhaust operations by the air supply and exhaust mechanism 80 are turned off.

When the wafer W is transported above the holder main body 70 by a wafer loader (not shown), the stage controller 19 moves up the center 34a to 34c via a vertical movement mechanism (not shown) under the instruction of the main controller 20. To rise. Here, when the rising amount of the center ups 34a to 34c reaches a predetermined amount, the wafer W on the wafer loader is moved to the center up 34a.
And the wafer loader is transferred to the holder main body 70.
Evacuate from above. Thereafter, the stage controller 19 moves down the center-ups 34 a to 34 c, so that the wafer W is placed on the holder main body 70.

When the wafer W is placed on the holder main body 70 as described above, the main controller 20 opens the solenoid valve V2 communicating with the high-speed exhaust vacuum chamber 46Ba of FIG. The gas in the space surrounded by the rim portion 28 and the wafer W is sucked (exhausted) at high speed. At this time, in the present embodiment, in order to improve the throughput, the vacuum chamber 46B
a to increase the suction pressure by, for example, -800.
It is set as high as hPa (in a high vacuum state).

In this way, the wafer loading is completed by holding the wafer W by suction at a high speed. Thereafter, main controller 20 closes solenoid valve V2 in FIG. 2 and opens solenoid valve V1 that communicates with first vacuum pump 46A that is normally used. Thereafter, the wafer W is pulled by the suction force of the first vacuum pump 46A.
Is adsorbed and held.

Here, between the time when the wafer W is sucked and held on the holder main body 70 and the time when the wafer W is taken out, the wafer W is laterally shifted due to the movement of the wafer stage WST or the like, so that the alignment accuracy and the like are not adversely affected. In this embodiment, the suction pressure of the normally used first vacuum pump 46A is set to, for example, − so as to minimize the deformation of the wafer W due to vacuum suction.
It is set as low as 266.5 hPa to -333.2 hPa (in a low vacuum state). Further, by making the suction pressure different between when the wafer W is placed on the holder main body 70 and when other operations are performed, the time required for loading the wafer W can be reduced.

On the other hand, when unloading the wafer W, the main controller 20 first closes the solenoid valve V1 in FIG. 2 and turns off the suction operation. Next, the main control device 20
The center-ups 34a to 34c are raised by a predetermined amount, and the gas supply valve V3 is opened to blow gas toward the bottom surface of the wafer W. Thereby, the above-mentioned vacuum state is immediately released.

When the center-ups 34a to 34c rise by a predetermined amount, the wafer W supported by the pins 32 and the rim 28 is transferred to the center-ups 34a to 34c. The wafer W is delivered from the center-ups 34a to 34c to the wafer unloader as the center-ups 34a to 34c move down while entering the lower side. Then, when the wafer unloader is retracted from the holder main body 70, the wafer unloading ends.

As described above, when the wafer W is unloaded from the holder body 70, the gas is blown to the bottom surface of the wafer W, so that the unloading time of the wafer W is reduced.

When vacuum ultraviolet light or the like is used as the illumination light IL, the gas on the optical path of the illumination light is replaced with a gas having a high transmittance to the illumination light, such as helium. In this case, it is desirable that the gas blown to the bottom surface of the wafer is also a gas having high transparency to illumination light. Further, it is desirable that the amount of gas blown to the bottom surface of the wafer be a very small amount so that the wafer does not float.

As is clear from the above description, the substrate holding device is constituted by the holder main body 70 and the air supply / exhaust mechanism 80. Also, the first vacuum pump 46A,
Solenoid valve V1, supply / exhaust pipe 40 and supply / exhaust paths 38A-38C
Thus, a vacuum suction mechanism is configured.

According to the exposure apparatus 100 of the present embodiment, similar to a normal scanning stepper, reticle alignment, baseline measurement of an alignment system (not shown),
After a predetermined preparation work such as wafer alignment such as EGA (enhanced global alignment),
The exposure operation of the step-and-scan method is performed as follows.

That is, in the stage controller 19, under the instruction of the main controller 20, the exposure of the first shot area (first shot) on the wafer W held on the holder main body 70 is performed based on the result of the wafer alignment. Wafer stage WST is moved to an acceleration start position for the purpose. Then, in the stage controller 19, the reticle stage RS
The relative scanning of the T and the wafer stage WST in the Y-axis direction is started, scanning exposure of the first shot on the wafer W is performed, and the circuit pattern of the reticle R is reduced and transferred to the first shot via the projection optical system PL.

Here, during the scanning exposure, the wafer W
Since the exposure needs to be performed in a state where the upper illumination area (exposure area) substantially coincides with the image forming plane of the projection optical system PL, the automatic operation based on the output of the focus position detection system (60a, 60b) is performed. Focusing and auto-leveling are executed by the main controller 20.

When the first-shot scanning exposure is completed, the stage controller 19 responds to an instruction from the main controller 20 to control the wafer stage WS.
T is moved stepwise in the X and Y axis directions, and is moved to an acceleration start position for exposure of a second shot (second shot area). Then, under the control of the main controller 20, the same scanning exposure is performed on the second shot as described above.

In this way, the scanning exposure of the shot area on the wafer W and the stepping operation between the shot areas are repeatedly performed, and the circuit pattern of the reticle R is sequentially transferred to all the shot areas to be exposed on the wafer W. You.

Next, the reason why the arrangement of the pins 32 in the holder main body 70 of the present embodiment is configured as described above will be described with reference to FIGS. 5 (A) to 6 (A).

First, the pin 3 located near the rim 28
2A and 2B, the reason why the local contact ratio of the pin portion located near the rim portion is made closer to the local contact ratio of the rim portion will be described with reference to FIGS. 5A and 5B. explain.
FIG. 5A is an enlarged plan view showing the vicinity of the outer edge of the holder main body 70, and FIG. 5B is a vertical cross-sectional view of the holder main body 70 of FIG. It is a figure which shows typically.

As described above, in the stage of manufacturing the holder body 70, the pin portion is placed on the base portion 26 in order to secure the flatness defined by the upper end portion of the pin portion 32 and the upper surface of the rim portion 28. After the formation of the rim 32 and the rim 28, the upper end and the upper surface thereof are polished.
At this time, in this embodiment, since the local contact ratio of the rim portion 28 and the local contact ratio of the pin portion are close to each other, the contact pressure of the polishing portion (processed portion) with the rim portion 28 during polishing is reduced. Polishing part (working part) for the pin part located near the rim part
Can be reduced. For this reason,
The processing step Δb between the pin 32 and the rim 28 shown in FIG. 5B is larger than the processing step Δa between the pin 32 ′ and the rim 28 ′ of the conventional wafer holder 25 ′ shown in FIG. Can be smaller.

Since the rim portion 28 serves as a sealing member for maintaining a vacuum between the wafer W and the base portion 26, a portion of the wafer located outside the rim portion 28 is large. It is located under atmospheric pressure. Therefore, the outer edge portion (portion c) of the wafer W is a free end.
In this case, the height of the outer edge portion (part c) of the wafer W is equal to the processing step Δb and the deformation amount of the wafer W caused by vacuum suction.
It depends on the angle θ ₁ determined by the two physical quantities. That is, as shown in FIG. 5B, in the holder main body 70 of the present embodiment in which the processing step Δb between the pin portion 32 and the rim portion 28 is set to be small, the wafer held on the holder main body 70 The height of the outer edge portion (c portion) of W can be reduced. Therefore, the distance between the pin portions 32 located near the rim portion 28 is reduced, and the local contact ratio of the pin portion located near the rim portion 28 is made closer to the local contact ratio of the rim portion, thereby reducing the wafer W. It is possible to eliminate or reduce the defocus factor at the time of exposure to the shot area near the outer edge.

Next, in the present embodiment, the reason why the interval between the adjacent pin portions 32 is set to be larger near the center point of the base portion 26 and narrower near the rim portion 28 with reference to FIG. explain.

FIG. 6A shows the wafer W on the assumption that the area on the back surface of the same wafer W as the shot area SA shown in FIG. 3 has been moved in the + X direction to the position of the shot area SA ′. FIG. 7 is a diagram schematically showing a change in a contact rate between a region on the back surface of the holder and the holder body 70 (the pin portion 32 and the rim portion 28). In FIG. 6A, a curve C1 indicated by a dashed line indicates a case where the pin portions 32 are arranged at equal intervals as in the conventional art (see FIG. 11A) (hereinafter, referred to as “constant pin arrangement” as appropriate). The curve C2 indicated by a solid line indicates a change in the contact ratio of the holder main body, and the curve C2 indicated by a solid line indicates a case where the pin portions 32 are densely arranged from the center of the upper surface of the base portion 26 to the vicinity of the rim portion 28 as in the present embodiment (hereinafter (Referred to as “continuous pin arrangement” as appropriate). In this case, the total contact ratio between the holder body having the fixed pin arrangement and the entire wafer represented by the curve C1 and the contact ratio between the holder body having the continuous pin arrangement and the entire wafer represented by the curve C2 are substantially equal. ing. In addition, as the wafer W, SEM
An 8-inch wafer of I standard (diameter = about 200 mm) is used, and the horizontal axis in FIG. 6A is the shot area SA (FIG. 3).
3) shows the position of the center SC.

In FIG. 6A, a state in which the shot area is located on rim portion 28 (shot area S in FIG. 3).
A ′), that is, when the center of the shot area is located at a position about 85 mm away from the center of the holder (see the center SC ′ of the shot area SA ′ in FIG. 3), the curve C
In the fixed pin arrangement indicated by 1, the contact ratio sharply increases. However, when the continuous pin arrangement is employed as in the present embodiment, the contact ratio gradually increases as the center of the shot area moves away from the center of the wafer W, as shown by the curve C2. From about 85
The increase in the contact ratio at a position distant by mm (see the shot area SA ′ in FIG. 3) can be slightly suppressed. The amount of increase in the contact ratio at a position about 85 mm away from the center of the wafer is much smaller than in the conventional case (curve C1).

That is, the surface shape of the holder changes substantially corresponding to the change of the contact ratio due to the nature of the polishing process.
By employing the continuous pin arrangement as in the present embodiment, no extreme processing step occurs between the rim portion 28 and the pin portion 32.

For this reason, the holder body 70 having the continuous pin arrangement is used.
In (curve C2), the contact rate of the entire wafer W with the holder body 70 is set substantially equal to the contact rate of the holder body (curve C1) with a fixed pin arrangement, and then the rim portion 28 and the pin portion 3 are set.
2 can be reduced. Accordingly, the wafer placed on the holder main body 70 having the continuous pin arrangement suppresses the deformation of the peripheral portion of the wafer due to the processing step without increasing the possibility of foreign matter being caught between the wafer and the holder main body 70. It is possible to do.

In this case, by adopting the continuous pin arrangement as described above, the surface shape of the holder main body 70 (and the wafer W held by the holder main body) has a gradual change as compared with the related art. The shot area SA is sufficiently smaller than the wafer W, and at the time of exposure, Z is determined based on the measurement value of the focus position detection system (60a, 60b) as described above.
By driving the tilt stage 30 in the Z-axis direction and the tilt direction with respect to the XY plane, it is possible to correct the height and tilt of the wafer surface. It hardly becomes a focus factor.

In this case, the arrangement interval (contact ratio) of the pins near the center of the holder main body is set so that the amount of deformation of the wafer during vacuum suction falls within an allowable range.

A curve C3 shown by a two-dot chain line in FIG. 6A shows the contact ratio of the virtual holder main body in which the rim portion 28 is removed and the continuous pin arrangement is performed up to the position of the rim portion 28. However, the pin portion 32 located near the rim portion 28
It is theoretically possible to completely eliminate the machining step as shown by the curve C3 by completely adjusting the contact rate of the rim portion 28 to the contact rate of the rim portion 28.

Next, the rim portion 28 of the holder body 70
A specific design method of the width (hereinafter, referred to as “rim width”) will be described.

Here, ρ is the total contact ratio (the ratio of the total area of the contact surface between the pin portion 32 and the rim portion 28 and the wafer W to the entire area of the rear surface of the wafer W), and the pin portion contact ratio (the pin portion) The ratio of the total area of the contact surface between the wafer 32 and the wafer W to the total area of the back surface of the wafer W) ρp, the radius of the wafer R [mm], the width of the rim portion b [mm], and the pin contact ratio If the error of the total contact ratio is set within 20%, that is, the contact area between the rim and the substrate is set within 20% of the contact area between the rim and the pin and the wafer, the following equation (1) is obtained. Can be expressed as (Ρ−ρp) /ρ≦0.2 (1)

Here, the term “within 20%” means that the inventor considers that the area where the plurality of pins and the wafer are in contact, the area where the rim and the wafer are in contact, and the number of pins and the rim and the wafer are By paying attention to the contact area (total contact area), various simulations, experiments, and the like were performed on the relationship between these areas and the processing steps, and as a result, the results were found to be sufficiently practical.

On the other hand, the rim 28 serving as a sealing member between the wafer W and the base 26 constituting the holder main body 70 cannot be set to the same diameter as the outer periphery of the wafer W. For this reason, if the rim portion 28 holds 1 mm inside of the outer peripheral portion of the wafer and the contact area of the pin portion is A, since there is usually a relation of b≪R, the total contact ratio ρ is expressed by the following equation (2). Is represented as ρ = {A + π (R-1) ² −π (R-1-b) ² } / πR ² {A + 2π (R−1) · b} / πR ² (2)

The pin portion contact ratio ρp is expressed by the following equation (3). ρp = A / πR ² (3)

Therefore, the above equation (1) is replaced by the above equation (2),
From (3), it is expressed by the following equation (4). (ρ-ρp) / ρ ≒ [{A + 2π (R-1) b} / πR ^2- (A / πR ² )] / ρ ≦ 0.2 (4)

When this equation (4) is rearranged and modified, the following equation (4) ′ is obtained. {2π (R-1) · b} / πR ² ≦ 0.2ρ (4) '

That is, according to equation (4) ′, the width b of the rim portion
It is understood that it is desirable to set the value within the range represented by the following equation (5). b ≦ (0.1ρR ² ) / (R−1) (5)

Here, for example, when an 8-inch wafer (diameter = about 200 mm) conforming to the SEMI standard is used, and if it is desired to set the overall contact ratio to 3% or less, the width b of the rim portion is obtained from the above equation (5). The range may be set to the following expression (6). b ≦ (0.1 × 0.03 × 100 ² ) / (100-1) ≒ 0.30 (mm) (6)

When a SEMI standard 12 inch wafer (diameter = approximately 300 mm) is used under the same conditions, the width b of the rim may be in the range of the following equation (7). b ≦ (0.1 × 0.03 × 150 ² ) / (150-1) ≒ 0.45 (mm) (7)

By adopting such a rim design method, the overall contact ratio between the holder body and the wafer is suppressed to 3% or less, and the contact area of the rim is kept within 20% of the entire contact area. It is possible to obtain a good holder main body in which foreign substances are not sandwiched between the step and the wafer.

As described in detail above, according to the present embodiment, the plurality of pins 32 of the holder
The wafer W is supported by the rim portion 28 while maintaining its flatness substantially. In this case, the plurality of pin portions 32
6 are arranged such that the distance between the adjacent pin portions 32 increases as the distance from the rim portion 28 increases.
As described above with reference to (A), the local contact ratio between the pin portion near the rim portion and the wafer can be made closer to the local contact ratio between the rim portion and the wafer. Therefore, according to the present embodiment, in the manufacturing stage of the holder main body 70,
When polishing is performed using a polishing apparatus or the like in order to obtain flatness on the wafer contact surface side of the holder main body 70, contact pressure from a polishing section (processed section) applied to each section of the rim section and the pin section near the rim section. Can be reduced, thereby making it possible to minimize the processing step between the two during polishing. That is, the processing step generated on the contact surface of the holder body with the wafer can be minimized, and as a result, the deformation (tilt angle) generated at the free end near the outer edge of the wafer can be reduced.

Further, according to the present embodiment, the contact area between the rim portion and the wafer is set to be 20% or less of the total contact area between the plurality of pin portions 32 and the rim portion 28 and the wafer. Also in this regard, as described above, each of the pin portions 32 and the rim portions 28 in the polishing process at the manufacturing stage are performed.
Can be minimized as much as possible.

Further, according to the exposure apparatus 100 of the present embodiment, the wafer W maintains a certain degree of flatness including the free end near the outer edge thereof, that is, the wafer W is placed on the holder main body 70 in a state without extreme unevenness. Will be retained. The position of the held wafer W in the Z-axis direction and the amount of tilt with respect to the XY plane are determined by the focus position detection system (60a, 60b).
, And based on the detection result, the main controller 2
By 0, the holder main body 70 is driven in the Z-axis direction and the tilt direction with respect to the XY plane via the stage control device 19 and the wafer stage drive unit 24. That is, focus / leveling control of the wafer W is performed. Thus, even if there is a gentle inclination on the wafer, by adjusting the inclination of the entire wafer and the position in the Z-axis direction via the holder main body 70, the exposure area on the wafer is projected onto the image plane of the projection optical system PL. The reticle pattern can be transferred onto the wafer with the (exposed area) matched. Therefore, high-precision exposure can be performed with almost no deterioration in pattern transfer accuracy due to defocus.

In the above embodiment, a case has been described in which the pin portion 32 is arranged such that the distance between the pin portion 32 and the rim portion 28 gradually increases as the distance from the rim portion 28 increases. However, the present invention is not limited to this. Absent. That is, the plurality of pin portions 32 are arranged such that, for example, the interval between the adjacent pin portions 32 changes stepwise in the vicinity of the rim portion 28, in the vicinity of the center portion of the holder main body 70, and in a portion therebetween. It can also be. Even in such a case, the pin portions 32 located near the rim portion 28 are arranged at a closer interval than the pin portions 32 located at other portions. For this reason, the local contact ratio between the pin portion near the rim portion and the wafer can be made closer to the local contact ratio between the rim portion 28 and the wafer. Therefore, similarly to the above embodiment, it is possible to minimize the processing step between the two, which occurs during the polishing processing, and as a result, the deformation (tilt angle) generated at the free end near the outer edge of the wafer is reduced. It is possible to reduce the size.

Further, when the pin portion and the rim portion meet the above-described design conditions (the contact area between the rim portion and the substrate is 20% of the total contact area).
%), And the pin portion may have a fixed pin arrangement as long as the pinching of foreign matter is allowed (for example, the contact ratio between the wafer and the entire holder body is 3% or less). That is, by setting the pin portion and the rim portion as shown by a curve C4 shown in FIG. 6B, the processing step at the rim portion is reduced as compared with the conventional case (curve C1). The deformation of the wafer held by the main body at the outer edge can also be suppressed. Therefore, it is possible to eliminate or reduce the defocus factor near the outer peripheral portion of the wafer W.

In the above embodiment, the plurality of pins 3
2 has been described as being arranged along multiple concentric circles centered on a reference point (center point) on the holder main body 70 corresponding to the center position of the wafer W, but the arrangement is not limited to this, and the arrangement is not limited to this. Relatively free. In other words, the pin portions 32 located in the vicinity of the rim portion 28 are arranged at a closer interval than the pin portions 32 located in other portions, and the other portions are arranged at intervals where the deformation of the wafer can be suppressed to an acceptable level. The arrangement is sufficient.

<< Second Embodiment >> Next, a second embodiment of the present invention will be described with reference to FIGS. 7 (A) and 7 (B). Here, the same reference numerals are used for the same or equivalent components as those of the first embodiment, and the description thereof will be simplified or omitted.

The exposure apparatus according to the second embodiment differs from the exposure apparatus according to the first embodiment only in the configuration of the holder main body. This is similar to the first embodiment. Therefore, the following description will focus on these differences.

FIG. 7A is a plan view showing a holder main body 170 according to the second embodiment.

As can be seen from FIG.
In the embodiment, double rim portions 28a and 28b are formed on the outer edge portion of the base portion 26 constituting the holder main body 170. The rims 28a and 28b have the same width and are arranged concentrically with a radius difference of about 1 to 3 mm. The gas in the space 51 between the rim portions 28a and 28b (see FIG. 7B) passes through the air supply / exhaust port (not shown) formed between the rim portions 28a and 28b on the upper surface of the base portion 26. The suction is performed by a supply / exhaust mechanism similar to the supply / exhaust mechanism 80 of the first embodiment. Other configurations of the holder main body are the same as those of the holder main body 70 of the first embodiment.

Hereinafter, the reason why the two rim portions 28a and 28b are provided on the holder body 170 will be described with reference to FIG. 7B which is a longitudinal sectional view of FIG. 7A.

As described in the first embodiment, the height of the outer edge portion (c portion) of the wafer W is determined by
And the amount of deformation of the wafer W caused by vacuum suction depends on an angle determined by two physical quantities.

Here, as described above, the rims 28a, 28a
By setting the distance between the rim portions 8b to about 1 to 3 mm, the areas thereof can be regarded as substantially equal, so that the processing speeds of the rim portions 28a and 28b become substantially equal, and the rim portion 2
The processing steps hardly occur in 8a and 28b. Therefore, the inclination angle θ ₂ of the free end (part c) of the wafer shown in FIG. 7B is caused only by the amount of deformation of the wafer W due to vacuum suction.

Therefore, when a single rim portion is employed (wafer W ′ shown by a dotted line in FIG. 7B), the angle θ ₂ can be made smaller than the angle θ ₁ of the free end. ing.

That is, by holding the wafer W by such a holder main body 170, the deformation (warping) of the outer edge of the wafer W can be suppressed as much as possible. At this time, since the rim part is provided twice,
It is expected that the contact area of the rim will be larger than that of the pin. For this reason, it is desirable to design the contact ratio between the pin portion and the double rim portion to satisfy the same conditions as in the first embodiment.

According to the second embodiment described above,
The same effects as those of the first embodiment can be obtained, and the deformation of the free end of the wafer can be further suppressed.

In the second embodiment, the case where the rim portion is provided in a double manner has been described. However, a large number of rim portions such as triple, quadruple, etc. may be provided. In this case, the rim width may be gradually reduced from the outer rim to the inner rim in order to reduce the contact ratio at the rim.

In each of the above embodiments, the rim 28,
Although the case where the pin portion 32 and the base portion 26 are integrally formed has been described, it goes without saying that the present invention is not limited to this. That is, all of the base portion, the pin portion (the first support member), and the rim portion (the second support member), or any one of them may be constituted by another member. In this case, at least one of the pin portion and the rim portion formed of a member different from the base portion may be fixed to the upper surface of the base portion using an adhesive or the like.

In the above embodiments, the case where a wafer (circular substrate) is used as the substrate has been described. However, the substrate may be a quadrangle or another polygon. In such a case, by setting the shape of the rim portion according to the shape of the substrate, the same effect as in the above embodiment can be obtained. Further, the shape of the base portion (a disk shape in each of the above embodiments) is not particularly limited.

In general, since the rim portion needs to maintain a vacuum and continuously contacts the wafer, the rim portion has a high local contact ratio (that is, the processing speed is low) and tends to protrude from the pin portion. However, when the contact area of the rim can be set small, a concave step may be generated on the rim. Therefore, it is desirable to set a lower limit on the contact ratio of the rim portion in the same manner as in the above embodiments, in which the upper limit is set such that the contact ratio of the rim portion is within 20% of the entire contact ratio.

In each of the above embodiments, the case where almost the entire upper surface of the rim portion is in direct contact with the back surface of the wafer W is described. However, the present invention is not limited to this. May be employed. In such a case, since the contact surface with the wafer becomes a protrusion, a gap corresponding to the height of the protrusion is generated between the upper surface of the rim and the wafer, and the vacuum suction force is slightly reduced.
Since the contact surface is a projection, a contact rate similar to the curve C3 shown in FIG. 6A can be realized, and the effect at this point is very large as described above. When a plurality of protrusions are provided on the upper end surface of the rim, it goes without saying that the plane defined by the plurality of protrusions is substantially the same height as the plane defined by the large number of pins 32.

In each of the above embodiments, the second support portion refers to a rim (convex portion) whose upper end is formed higher than its peripheral portion. However, the concept of the second support portion is as follows. Is not limited to this. For example, FIG.
As shown in the holder main body 270 shown in (A), the center portion of the base portion 126 is dug down below the outer edge portion, and the inner bottom surface 127 of the dug-down recess is used as a reference surface and a position higher than the reference surface. An annular portion near the inner peripheral surface of the portion 128 can be used as the second support portion. In this case, the diameter of the inner peripheral surface is adjusted so that the width of the contact surface between the portion 128 and the wafer W (that is, the distance from the outer edge to the inner peripheral surface of the wafer W) satisfies the above equations (6) and (7). It is desirable to set

As shown in the holder main body 370 of FIG. 8B, an annular convex portion 228 is further provided on the inner bottom surface 127 of the concave portion.
And when holding the wafer W, the part 1
Annular concave portion 13 formed between the annular convex portion 228 and the annular convex portion 228
The gas in 4 may be sucked by the same air supply and exhaust mechanism as in the second embodiment described above.

Further, in each of the above embodiments, the case where the suction mechanism for sucking the wafer onto the holder body is the vacuum suction mechanism has been described, but the present invention is not limited to this. That is, an electrostatic chuck or the like may be employed as the suction mechanism. In such a case, the second supporting portion does not need to have a function as a sealing member, and thus does not need to be annular or endless. it can.

In each of the above embodiments, after the surface of the holder main body is processed to form the pin portion and the rim portion, the surface is coated with the same or different material as the holder main body, and the final finishing is performed. You may do it.

In each of the above embodiments, F is used as the light source.
_Although a pulsed laser light source in the vacuum ultraviolet region such as a _two- laser laser and an ArF excimer laser is used, the invention is not limited to this.
An ultraviolet light source such as an rF excimer laser light source (output wavelength 248 nm) or an Ar ₂ laser light source (output wavelength 126
nm) may be used. Also,
For example, not only laser light output from each of the above light sources as vacuum ultraviolet light, but also single-wavelength laser light in the infrared or visible range oscillated from a DFB semiconductor laser or a fiber laser, for example, erbium (Er) (or A harmonic wave amplified by a fiber amplifier doped with erbium and ytterbium (Yb) and converted to ultraviolet light using a nonlinear optical crystal may be used.

In each of the above embodiments, the case where the present invention is applied to a scanning exposure apparatus such as a step-and-scan method has been described. However, the scope of the present invention is not limited to this. is there. That is, the present invention can be suitably applied to a step-and-repeat type reduction projection exposure apparatus.

The illumination optical system and the projection optical system composed of a plurality of lenses are incorporated in the main body of the exposure apparatus, and the optical adjustment is performed. The exposure apparatus according to the above-described embodiment can be manufactured by connecting wirings and pipes and performing overall adjustment (electrical adjustment, operation confirmation, and the like). It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

In each of the above embodiments, the case where the present invention is applied to an exposure apparatus for manufacturing a semiconductor has been described. However, the present invention is not limited to this. For example, a liquid crystal display element pattern is transferred to a square glass plate. The present invention can be widely applied to an exposure apparatus for a liquid crystal, an exposure apparatus for manufacturing a thin-film magnetic head, an image sensor, a micromachine, a DNA chip, and the like.

In addition to a micro device such as a semiconductor device, a glass substrate or a mask for manufacturing a reticle or a mask used in an optical exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, or the like. The present invention is also applicable to an exposure apparatus for transferring a circuit pattern onto a silicon wafer or the like. Here, in an exposure apparatus using DUV (far ultraviolet) light or VUV (vacuum ultraviolet) light, a transmission type reticle is generally used, and quartz glass is used as a reticle substrate.
Fluorine-doped quartz glass, fluorite, magnesium fluoride, quartz, or the like is used.

<< Device Manufacturing Method >> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus in a lithography process will be described.

FIG. 9 shows a flowchart of an example of manufacturing devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). As shown in FIG. 9, first, step 201
In the (design step), function / performance design of the device (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Continued
In step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. on the other hand,
In step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

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

Finally, step 206 (inspection step)
In step S205, inspections such as an operation check test and a durability test of the device created in step 205 are performed. After these steps, the device is completed and shipped.

FIG. 10 shows a detailed flow example of step 204 in the semiconductor device. In FIG. 10, in step 211 (oxidation step), the surface of the wafer is oxidized. Step 212 (CV
In step D), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), electrodes are formed on the wafer by vapor deposition. Step 214
In the (ion implantation step), ions are implanted into the wafer. Each of the above steps 211 to 214 constitutes a pre-processing step in each stage of wafer processing, and is selected and executed in accordance with a necessary process in each stage.

In each stage of the wafer process, when the above-mentioned pre-processing step is completed, the post-processing step is executed as follows. In this post-processing step, first, in step 2
In 15 (resist forming step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred onto the wafer by the lithography system (exposure apparatus) and the exposure method described above. Next, in Step 218 (etching step), the exposed members other than the portion where the resist remains are removed by etching. Then, in step 219 (resist removing step), unnecessary resist after etching is removed.

By repeating these pre-processing and post-processing steps, multiple circuit patterns are formed on the wafer.

By using the device manufacturing method of the present embodiment described above, the exposure apparatus of the above embodiment is used in the exposure step (step 216), so that the reticle pattern can be accurately transferred onto the wafer. As a result, it is possible to improve the productivity (including the yield) of a highly integrated device.

[0132]

As described above, according to the substrate holding apparatus of the present invention, there is an effect that a processing step generated on a contact surface with a substrate during polishing can be minimized.

Further, according to the exposure apparatus of the present invention, there is an effect that the exposure accuracy can be improved.

Further, according to the device manufacturing method of the present invention, there is an effect that the productivity of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to a first embodiment.

FIG. 2 is a plan view showing a holder main body and an air supply / exhaust mechanism of FIG.

FIG. 3 is a plan view showing an arrangement of pins of the holder body of FIG. 2;

FIG. 4 is a sectional view showing the inside of a base portion of the holder main body.

FIG. 5A is an enlarged plan view showing the vicinity of a rim portion (near an outer edge portion) of a holder main body, and FIG.
It is a figure which shows typically the cross section near the rim part of a holder main body.

FIGS. 6A and 6B are views for explaining the effect of the pin arrangement of the holder main body.

FIG. 7A is a plan view showing a holder main body according to a second embodiment, and FIG. 7B is a vertical cross-sectional view near the outer edge of the holder main body of FIG. 7A. It is.

FIGS. 8A and 8B are views for explaining a modified example of the holder main body.

FIG. 9 is a flowchart illustrating an embodiment of a device manufacturing method according to the present invention.

FIG. 10 is a flowchart showing details of step 204 in FIG. 9;

11 (A) is a plan view showing a conventional wafer holder, and FIG. 11 (B) is a vertical sectional view showing a state where a wafer is placed on a wafer holder 25 ′ of FIG. 11 (A). It is an end elevation.

[Explanation of symbols]

Reference numeral 19: stage control device (part of the driving device), 20: main control device (part of the driving device), 24: wafer stage driving unit (part of the driving device), 26: base unit (one of the holding device main body) ), 28, 28a, 28b ... rim part (second support part), 32 ... pin part (first support part), 38A to 38C ...
Supply / exhaust passage (part of vacuum suction mechanism) 40 ... Supply / exhaust pipe (part of vacuum suction mechanism) 46A ... First vacuum pump (part of vacuum suction mechanism), 51 ... Space, 60a, 60b ... Focal position detection System, 70: Holder main body (holding device main body, part of substrate holding device) 80: Supply / exhaust mechanism (part of substrate holding device), 1
00: exposure apparatus, 134: annular concave part, 228: annular convex part, PL: projection optical system, R: reticle (mask), V1
… Solenoid valve (part of vacuum suction mechanism), W… Wafer (substrate).

Claims (12)

[Claims] 1. A substrate holding device for holding a flat substrate, comprising: a plurality of substrates for supporting the substrate, each of which is disposed in a region of a predetermined area such that respective front ends thereof are located on substantially the same plane. A protruding first support portion, disposed outside the region,
A holding device main body surrounding at least most of the outside of the region and having a plurality of first support portions and a second support portion for supporting the substrate while maintaining its flatness substantially; A substrate, wherein at least a first support portion of the first support portion located near the second support portion is arranged at a closer interval than a first support portion located in another portion. Holding device. 2. The method according to claim 1, wherein the plurality of first support portions are adjacent to each other.
2. The substrate holding device according to claim 1, wherein the distance between the support portions is arranged to be wider as the distance from the second support portion increases. 3. 3. The plurality of first support portions are arranged on a plurality of concentric circles around a reference point on the holding device main body corresponding to a center position of the substrate. 3. The substrate holding device according to 1 or 2. 4. The apparatus according to claim 1, further comprising a suction mechanism for sucking the substrate to a tip portion of each of the plurality of first support portions and an upper end portion of the second support portion.
4. The substrate holding device according to claim 3. 5. The second support portion has an annular inner peripheral surface that completely surrounds a region where the plurality of first support portions are arranged, and the suction mechanism is configured to move the substrate to the holding device main body. 5. The vacuum suction mechanism according to claim 4, wherein a vacuum formed in a space formed inside the inner peripheral surface of the second support portion by the substrate and the holding device main body in a supported state is provided. 6. The substrate holding device as described in the above. 6. The second support portion has an annular convex portion arranged concentrically and an annular concave portion on the outer peripheral side of the annular convex portion, and the vacuum suction mechanism also holds the annular concave portion in a vacuum state. The substrate holding device according to claim 5, wherein: 7. The method according to claim 6, wherein the annular convex portions are provided in a double or more concentric manner, and the vacuum suction mechanism also evacuates a space between adjacent annular convex portions. The substrate holding device as described in the above. 8. A contact area between the second support portion and the substrate is set to 20% or less of a total contact area between the plurality of first support portions and the second support portion and the substrate. The substrate holding device according to claim 1, wherein: 9. A contact area between the plurality of first support portions and the second support portion and the substrate occupying an entire area of a surface of the substrate supported by the first and second support portions. 9. The substrate holding device according to claim 8, wherein the ratio is set to 3% or less. 10. A substrate holding device for holding a flat substrate, comprising: a plurality of substrates for supporting the substrate, each of which is disposed within a region of a predetermined area such that respective front end portions thereof are located substantially on the same plane. A protruding first support portion, disposed outside the region,
A second supporting portion surrounding at least a large part of the outside of the region and having a plurality of first supporting portions and a second supporting portion for supporting the substrate while maintaining its flatness substantially; A substrate holding device, wherein a contact area between a support portion and the substrate is set to 20% or less of a total contact area between the plurality of first support portions and the second support portion and the substrate. 11. An exposure apparatus for transferring a pattern formed on a mask onto a substrate via a projection optical system, wherein the substrate holding apparatus according to any one of claims 1 to 10; and the substrate holding apparatus. A focus position detection system for detecting the position of the substrate surface held by the device in the direction of the optical axis of the projection optical system and the amount of tilt with respect to a plane orthogonal to the direction of the optical axis; based on the detection result of the focus position detection system A driving device that drives the substrate holding device in at least one of the optical axis direction and a tilt direction with respect to a plane orthogonal to the optical axis direction. 12. A device manufacturing method including a lithography step, wherein in the lithography step, exposure is performed using the exposure apparatus according to claim 11.