JP2003258071A - Substrate holding apparatus and aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To exactly discharge static electricity accompanied by substrate holding. <P>SOLUTION: A substrate holding apparatus comprises a holding member 14 that is made of a nonmetallic material and abut on a portion of the reverse face of a substrate to be held, base members 12A to 12C which are made of metallic materials and have ends to which the holding members are adhered and fixed, and conductive members 17 that have elastic properties and are adhered to the holding members and base members. Portions of the holding members adhered to the conductive members are polished. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used in a process of manufacturing an electronic circuit device such as a semiconductor device or a liquid crystal display device, and more particularly to a substrate holding device for holding a substrate such as a semiconductor wafer or a glass plate. Regarding

[0002]

2. Description of the Related Art In a precision exposure apparatus used in a photolithography process (coating a photosensitive solution on a substrate-exposure by developing), a plurality of substrates (wafers or glass plates) to be exposed are stored. Take out one board from the carrier or the board stock section for inline,
The multi-joint type robot arm or the like automatically conveys it to the pre-alignment unit, and the pre-aligned substrate is further transferred to the vacuum suction type substrate holder on the substrate stage in the exposure apparatus.

The vacuum suction type substrate holder is designed so that a transferred image of a mask pattern to be exposed is formed on a photosensitive layer (resist layer) of a substrate with desired image quality (resolution, film reduction of the photosensitive layer, etc.). Its main function is to correct the surface of the substrate to an extremely flat state. Therefore, the mounting surface of the substrate holder is finished to an extremely flat surface of, for example, about ± 0.2 μm. Recently, in this type of substrate holder, the base material is ceramics, and a thick film (for example, a layer of silicon carbide or titanium carbide having a thickness of about 300 μm) exhibiting good conductivity is deposited on the surface thereof by the CVD method. After that, a groove for vacuum suction is formed by mechanical cutting in the thick film layer, or the entire surface is optically polished.

The strictness of the flatness of the substrate holder as described above is caused by the decrease in the depth of focus that is caused by the yearly improvement in the resolving power of the projection type exposure apparatus which is the mainstream as the precision exposure apparatus. . That is, when the depth of focus of the projection exposure apparatus becomes smaller, the flatness (local flatness) in the local area of the substrate surface corresponding to the projection field of the projection optical system.
Is getting tougher.

Therefore, particularly in the projection type exposure apparatus, it is necessary to sufficiently secure the accuracy of the flattening correction of the substrate by the substrate holder. For that purpose, it is desirable to obtain a uniform suction force with the back surface of the substrate on the entire mounting surface of the substrate holder. However, the uniform suction force here does not necessarily mean that the entire back surface of the substrate is vacuum-sucked, but the back surface of the substrate is partially vacuum-sucked by a plurality of localized suction grooves or the like. Even in the case, if the desired flatness is ensured in consideration of the original shape of the substrate and the minute warpage, it means that the uniform suction force is obtained.

On the other hand, from the viewpoint of the substrate transfer mechanism, if the structure is such that the transfer arm holds the upper surface of the substrate in contact,
It is possible to install the substrate on the mounting surface of the substrate holder or remove the substrate that is in close contact with the mounting surface. However, since the substrate handled here is the device forming surface on which the resist layer is applied, the transfer arm suckingly holds the upper surface of the substrate in terms of adhesion of dust and damage to the device forming surface. Not preferable.

Therefore, as disclosed in, for example, Japanese Unexamined Patent Publication No. 1-214042, it is arranged at the central portion of the substrate holder (or at three positions substantially equidistant from the center of the holder).
A space between the lifted substrate and the holder mounting surface is provided by providing a vertically movable center-up part (or three support members) for lifting and supporting the substrate from the holder mounting surface by a certain amount when the substrate is transported. There is known a device in which a transfer arm can adsorb and hold the back surface of a substrate by advancing the transfer arm into the inside.

[0008]

By the way, when a metal is used as the material for the tip end portion (the portion that contacts the substrate) of the center-up portion, the back surface of the substrate is contaminated by the metal, and the quality of the manufactured device is improved. Or performance may be adversely affected. Therefore, a pedestal made of a metallic material and a holding member made of a non-metallic material having a low expansion coefficient such as ceramics attached to the pedestal made of a metallic material with an adhesive are used as the center-up portion.

However, by providing a holding member made of a non-metal material such as ceramics at the tip of the center-up portion, metal contamination of the substrate is prevented, but due to friction or the like caused by contact between the substrate and the holding member, When the holding member or the substrate is charged with static electricity to promote the adsorption of floating substances to the substrate or the holding member, or to adversely affect the separability of the substrate from other members (including the holding member) that are in contact with the substrate. There was such a problem.

Therefore, a conductive tape is attached to the side surface of the holding member (all or a part of the surface other than the holding surface of the substrate and the bonding surface with the pedestal) and the pedestal, and the conductive tape is accumulated on the substrate or the holding member. It is conceivable to prevent the failure due to the static electricity by positively guiding and opening the static electricity to the pedestal.

However, when ceramics, for example, is used as the holding member, its surface is generally rough, and a sufficient contact area cannot be obtained on the surface where the conductive tape is attached, so that static electricity may not be sufficiently released. found.
It was also found that when ceramics were sintered, an oxide film that had no conductivity or deteriorated conductivity was formed on the surface, resulting in unstable conduction.

The present invention has been made in view of the above circumstances, and when a non-metal material is used for the contact portion with the substrate, the substrate holding device and the substrate holding device capable of sufficiently discharging static electricity. An object is to provide an exposure apparatus provided with such a substrate holding device.

[0013]

In the following description of this section, the present invention will be described in association with the member reference numerals shown in the drawings showing the embodiments. It is not limited to the members shown in the drawings attached with.

According to the first aspect of the present invention, the substrate (W)
A holding member (14) made of a non-metallic material that abuts a part of the back surface of the substrate for holding the pedestal, and a pedestal member (12) made of a metallic material that is adhesively fixed to the tip of the holding member.
A to 12C) and a flexible conductive member (17) attached across the holding member and the pedestal member, and at least a surface of the holding member to which the conductive member is attached. There is provided a substrate holding device having a polishing surface obtained by polishing.

According to a second aspect of the present invention, the substrate (W)
A substrate holder (1) having a substrate mounting surface (1A) that comes into contact with the back surface of the substrate, a holding member (14) made of a non-metallic material that comes into contact with part of the back surface of the substrate, and the holding member has its tip portion. A pedestal member (12) made of a metal material that is adhesively fixed to the
A to 12C), a flexible conductive member (17) attached to the holding member and the pedestal member, and a contact portion of the holding member with respect to the substrate from the substrate mounting surface. The buried position and the position protruding from the substrate mounting surface (P
and a drive means (34) for moving the pedestal member and the substrate holder relative to each other so as to be set in (u), and polishing the surface of the holding member to which the conductive member is attached by polishing. There is provided a substrate holding device characterized by the above.

In the substrate holding apparatus according to the first or second aspect of the present invention, the portion of the holding member that abuts the substrate to which the conductive member is attached is a polished surface that has been polished.
The holding member and the conductive member are uniformly and sufficiently contacted,
It becomes possible to guide the static electricity accumulated in the substrate or the holding member to the pedestal member through the conductive member, and to discharge the static electricity sufficiently, and the obstacle caused by the charging of the holding member or the substrate. Can be reduced.

According to a third aspect of the present invention, the substrate (W)
A substrate holder (1) having a substrate mounting surface (1A) that abuts the back surface of the substrate, a holding member (14) that abuts a part of the back surface of the substrate, and a state in which the holding member is electrically insulated. Pedestal member (12A to 12C) fixed to the tip thereof
A substrate holding device comprising: a conductive member (17) for electrically connecting the holding member and the pedestal member; and a driving unit (34) for relatively moving the substrate holder and the pedestal member. Provided.

Here, the conductive member may be, for example, a conductive adhesive for fixing the holding member and the pedestal member,
It may be attached over the holding member and the pedestal member. At this time, when a thin film (such as an oxide film) that deteriorates conductivity is formed in the portion of the holding member to which the conductive member is attached, it is desirable to polish the portion. In this case, the holding member is made of a conductive material (for example, Al ₂ O ₃ mixed with a conductive material such as TiC or TiC) and deteriorates the conductivity on the firing surface, or an oxide film having no conductivity. Even if is molded, the conduction does not become unstable. Alternatively, claim 6
As described above, it is desirable that the holding member be coated with a material (for example, DLC, TiN, etc.) capable of forming a film with a surface roughness that does not make the conduction unstable. In this case, for example, the surface roughness of the material formed to have a thickness of about several tens to several tens of μm is similar to that of the above-mentioned polished surface. Can also obtain sufficient conduction. Furthermore, at least the base material of the substrate holder may be made of low thermal expansion ceramics, and the substrate holder and the pedestal member may be grounded.

According to a fourth aspect of the present invention, claims 1 to
An exposure apparatus comprising the substrate holding device according to any one of 7 above.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

First, a step-and-scan reduction projection exposure apparatus will be briefly described as an example of an exposure apparatus that can employ the substrate holding apparatus according to the present invention. This reduction projection exposure apparatus projects a reticle and a wafer in a state in which a part of a pattern on a reticle as a mask is reduced and projection exposed onto a resist-coated wafer as a photosensitive substrate through a projection optical system. By synchronously moving with respect to the optical system, the reduced image of the pattern on the reticle is sequentially transferred to each shot area on the wafer to form a semiconductor device on the wafer.

For example, a KrF excimer laser (wavelength 248
The laser beam pulse-emitted from the exposure light source that oscillates the laser beam on the reticle held on the reticle stage via the beam shaping / modulation optical system, optical integrator, aperture stop, relay lens, condenser lens, etc. Illuminates a rectangular illumination area with a uniform illuminance distribution.
An image obtained by reducing the pattern in the illumination area on the reticle with a projection magnification α (α is, for example, 1/4, 1/5, etc.) via a projection optical system is projected and exposed on a wafer coated with a photoresist. . The wafer is sucked and held on the wafer stage via the substrate holder (wafer holder), and the reticle stage and the wafer stage are driven under the control of the control device, and the wafer and the reticle are moved in the same or opposite directions at a predetermined speed ratio. By the synchronous movement, the pattern on the reticle is transferred to the shot area of the wafer.

The apparatus which can adopt the substrate holding apparatus according to the present invention is not limited to such a step-and-scan type reduction projection exposure apparatus, but an aligner,
It may be another projection type exposure apparatus such as a stepper or a lens scanner, or may be another processing apparatus, measuring apparatus or inspection apparatus that needs to transfer, position and fix the substrate to be processed.

Next, a mechanism for transferring the wafer to and from the substrate holder will be described including the structure of the substrate holder. FIG. 1 is a perspective view schematically showing a substrate holding device (a substrate holder and a center-up member) according to an embodiment of the present invention, in which the center-up member 10 is lifted from a surface of the substrate holder 1 by a predetermined amount. The state is shown. FIG. 2 is an enlarged perspective view of the center-up member shown in FIG.

In FIG. 1, the substrate holder 1 has a diameter of 300.
A disk-like shape having a mounting surface 1A having a substantially circular outer shape is formed so as to adsorb and hold a circular semiconductor wafer of 12 mm (mm), and although not shown, almost the entire mounting surface 1A is formed. Has a plurality of suction grooves or a plurality of suction holes for adsorbing the back surface of the wafer at appropriate intervals and arrangements. Further, although not shown in FIG. 1, the substrate holder 1 of this example is a so-called pin chuck holder in which a large number of minute convex portions (pins) for supporting a semiconductor wafer are formed on the mounting surface 1A.

In the central portion of the substrate holder 1, three penetrating portions 2A, 2B, 2C extending in the radial direction from the center thereof are arranged at intervals of about 120 ° on the circumference centered on the center of the mounting surface 1A. Is formed by. Therefore, the penetrating portions 2A to 2C are formed into three spokes (or petals) that are connected at the center of the substrate holder 1 when viewed in the mounting surface 1A (XY plane). Further, in the case of a 12-inch wafer, the length from the center of the mounting surface 1A to the radial ends of the penetrating portions 2A to 2C is 2
The width of each penetrating portion 2A to 2C is set to about 8 to 14 mm.

The center-up member 10 is the substrate holder 1
Has a shaft portion 13 passing through a through portion at the center of the shaft portion, and three spoke-shaped support portions (base members) 11A, 11B, and 11C integrally molded or fixed to the upper portion of the shaft portion 13. The spoke-shaped support portions 11A to 11C extend linearly in the radial direction at an arrangement of 120 ° with respect to each other when viewed in the XY plane, and each of the spoke-shaped support portions 11A to 11C extends from the penetration portion 2A to
It is shaped so that it can sink in 2C without contact.
Therefore, each of the spoke-shaped support portions 11A to 11C has a length L from the center of about 19 to 34 mm and a circumferential width of 5 to 5 mm.
It is set to about 12 mm, which is set to be slightly smaller than both the radial length and the circumferential width of the corresponding penetrating portions 2A to 2C.

At the upper end of each of the spoke portions 11A to 11C, a concave portion as a suction groove for vacuum-sucking the back surface of the wafer is formed so as to extend in the radial direction. This concave portion has three spoke portions 11A to 11C. Is also commonly formed in the central portion where the crosses, and the entire upper end surface of the center-up member 10 contributes to vacuum suction of the wafer. Therefore, compared with the conventional method in which the vacuum suction is performed at the tip of three independent support members (for example, pipes having a diameter of about 4 mm), the suction force is significantly improved and stable wafer holding becomes possible.

The center-up member 10 is shown in detail in FIG.
The three spoke portions 11A to 11 are configured as shown in FIG.
C is a spoke pedestal portion 12 that extends in a radial direction from the shaft portion 13 and is integrally molded (or fixed by another member).
A, 12B, 12C, and this pedestal portion 12A-12C
Is formed in a taper shape such that the thickness in the height direction (Z direction) increases from the tip end side in the radial direction toward the shaft portion 13 side, and the upper end surfaces (suction holding surfaces) of the spoke portions 11A to 11C themselves. Has a strength structure that maintains good flatness.

The pedestal portions (pedestal members) 12A to 12C are made of a metal material, for example, stainless steel (SUS), and are integrally fixed to the shaft portion 13 which is also made of a metal material. The pedestal portions 12A to 12C and the shaft portion 13 may be integrally formed with each other. The shaft portion 13
Is grounded via a ground circuit (not shown).

On the upper surface of the pedestal portions 12A to 12C, an annular convex portion (holding member) 14 contacting the back surface of the wafer is arranged along the outer shape of the three spoke portions 11A to 11C in the XY plane. . This annular convex portion 14 is made of a low thermal expansion non-metallic material (in this example, a conductive non-metallic material such as T
It is formed of Al ₂ O ₃ or the like in which a conductive material such as iC or TiC is mixed, and is adhesively fixed to the upper surfaces of the pedestals 12A to 12C using an adhesive made of resin, for example. It is preferable that this adhesive has conductivity, but since it has a ground structure using a conductive tape described later, it may be insulating.

As the low thermal expansion material forming the base material of the annular convex portion 14, for example, low thermal expansion ceramics having a thermal expansion coefficient (linear expansion coefficient) of 0.1 ppm or less can be used. Glass ceramics or cordierite-based or alumina-based ceramics can be used as the low thermal expansion ceramics.

Of these, when glass ceramics is used, it has a crystallization phase and a glass phase in a mixed state,
It is advisable to employ an ultra-precision glass-ceramic containing about 70 to 78% of a crystallized phase having a high quartz structure, for example, one commercially available as "Zerodur (trade name)". Since the glass phase has a positive thermal expansion property and the crystallization phase has a negative thermal expansion property, it is possible to control and adjust the crystallization conditions as appropriate to adjust its content to a specific temperature range. This is because the coefficient of linear thermal expansion can be arbitrarily set within and the coefficient of thermal expansion can be made extremely small or zero (or minus). Since such glass-ceramics have a non-oriented surface with few pores and have almost the same chemical characteristics and strength as ordinary glass, they can be processed using the same machines and tools as ordinary glass. It is possible and convenient in that respect.

After the ceramic base material having such a low thermal expansion is processed into a predetermined shape, the annular convex portion 14 is uniformly coated with a material having a hardness higher than that of the ceramics over the entire area to be the wafer mounting surface. To be done. It is preferable that the coating layer has little dust generation and good conductivity. In the case of the base material described above, for example, DLC, TiC, or TiN can be used as the coating material, and the thickness thereof is about several μm to several tens of μm (for example, 10 μm). The coating method is CV
D (Chemical Vapor Deposition)
on) method can be used. The upper end surface of the annular convex portion 14 coated in this way (contact surface with the wafer)
Is polished by a lapping device or the like so as to have a flatness such that no leakage occurs when holding the wafer by suction.

Further, all or part of the side surface of the annular convex portion 14 (excluding the contact surface with the wafer and the bonding surface with the pedestal portions 12A to 12C) is polished by using a lapping machine or the like. . The surface roughness of this polished surface (polished surface) is set to about 3.2 μmRa or less in this embodiment. A coating similar to the coating on the upper end surface of the annular convex portion 14 can be applied to the side surface of the annular convex portion 14, and in this case, the coating layer on the side surface is polished. The polishing surface provided on the side surface of the annular convex portion 14 may be formed on a portion to which a conductive tape described later is attached, and the entire side surface does not necessarily have to be the polishing surface.

FIG. 3 is a sectional view taken along the line AA of FIG. As shown in the figure, the annular convex portion 14
Is bonded and fixed on the pedestal portion 12A (to 12C) via the adhesive 18. Further, a conductive tape 17 (conductive member) is attached so as to straddle the polishing surface of the side surface of the annular convex portion 14 and the pedestal portions 12A to 12C. here,
The conductive tape 17 is attached to each of the spokes 11A to 11C, one on each side (FIG. 2).
reference). However, the conductive tape 17 may be adhered without a gap over the entire circumference of the annular convex portion 14, or a plurality of conductive tapes 17 may be adhered intermittently.

The conductive tape 17 as described above is attached to the annular convex portion 1
4 and the pedestal portions 12A to 12C are adhered to each other. When the annular convex portion 14 is adhesively fixed to the pedestal portions 12A to 12C via an adhesive, the adhesive is usually insulative (usually The adhesive is insulative), the static electricity generated by the friction caused by the contact between the annular convex portion 14 and the wafer is accumulated in the annular convex portion 14 and adversely affects the peelability from the wafer, or the adsorption of dust or the like. This is because such static electricity is introduced to the pedestals 12A to 12C via the conductive tape 17 and discharged to the ground via the above-mentioned ground circuit. Even if a conductive adhesive is used as the adhesive, it is effective to use the conductive tape 17 as in the present embodiment for more reliable discharge of static electricity.

Further, the reason why the portion of the side surface of the annular convex portion 14 to which the conductive tape 17 is adhered is the polishing surface is that in the case of ceramics or the like, since there are relatively large irregularities on the surface as it is, conductive The area of contact with the conductive tape 17 may be small and electrostatic discharge may not be sufficiently performed, or there may be no conductivity on the surface during sintering of ceramics, or an oxide film that deteriorates conductivity may be formed to cause conduction. May become unstable, and by using such a polished surface, the conductive tape 17 makes uniform and uniform contact, so that it is possible to secure a sufficient contact area, and electrostatic discharge performance is improved. It is because it can improve.

Referring again to FIG. A concave portion is formed at a constant depth on the entire inner side of the annular convex portion 14.
Inside this recess, suction holes 15A, 15B, 15C formed by penetrating the inside of the pedestals 12A to 12C near the tip of each of the spokes 11A to 11C, and a pipe 16 passing through the inside of the shaft portion 13 are provided. Via a vacuum source.

Here, it is also important to set the upper end surface of the annular convex portion 14 and the mounting surface 1A of the substrate holder 1 shown in FIG. 1 to be as parallel as possible. When the parallelism is poor, when the wafer is mounted on the mounting surface 1A of the substrate holder 1 by lowering the center-up member 10 from the state where the wafer is sucked and held on the upper end of the protruding center-up member 10, the wafer is mounted. This is because the wafer is laterally displaced when the vacuum suction force is generated on the mounting surface 1A side because the wafer is tilted and lowered onto the surface 1A.

Next, the structure of the substrate stage mechanism in the projection exposure apparatus in which the substrate holder 1 and the center-up member 10 shown in FIGS. 1 and 2 are mounted will be briefly described with reference to FIG. FIG. 4 shows a partial cross section of a substrate stage mechanism that moves two-dimensionally in the XY plane by an air bearing type guide and a linear motor, and the substrate holder 1 is attached to the upper side of the XY stage mechanism.

In FIG. 4, air bearing pads 21A and 21B are formed on the surface of the surface plate 20 which extends in the XY plane.
The stage main body 22 is provided via the. Air pads 23A and 2A are provided in openings provided at the center of the stage body 22 so as to penetrate in the X direction (direction perpendicular to the plane of the drawing).
A movable linear guide member 24 extending in the X direction passes through 3B. Both ends of the movable linear guide member 24 are Y
The Y-direction movable member 25 is fixed to the Y-direction movable member 25.
Are supported on the surface plate 20 via air pads 26A and 26B.

The Y-direction movable member 25 is guided and supported by a fixed linear guide member 27, which is fixed to the surface plate 20 so as to extend linearly in the Y direction, via an air pad. A movable linear guide member 24 is provided around the stage body 22.
Two X linear motors 28A and 28B are arranged in parallel with, and the stators (either the coil row or the magnet row) of the motors 28A and 28B are fixed to the Y-direction movable members 25 on both sides.

Although not shown in FIG. 4, the Y-direction movable member 25 is driven in the Y-direction by a Y linear motor arranged in parallel with the fixed linear guide member 27. Therefore, by driving the Y linear motor, the Y direction movable member 25, the movable linear guide member 24, and the two X linear motors 28A, 28
B integrally moves in the Y direction, and at the same time, the stage main body 22 guided and supported by the movable linear guide member 24 also includes the surface plate 2
Move 0 in Y direction. Further, the movable linear guide member 24 is driven by driving the two X linear motors 28A and 28B.
The stage main body 24 guided and supported by moves on the surface plate 20 in the X direction.

On the stage body 22 as described above,
Three Z-direction linear actuators 30A, 30B, 30
A ZL stage 32 for translationally moving in the Z direction by a small amount by C (however, 30C is omitted) and for adjusting a slight amount of inclination with respect to the XY plane is provided, and a side end portion of the ZL stage 32 is provided with a stage. Coordinate position in XY directions, Z
A movable mirror 38 that reflects a beam from a laser interferometer that measures a minute rotational displacement around the axis (yawing), a minute rotational displacement around the X axis (rolling), and a minute rotational displacement around the Y axis (pitching) is fixed. There is.

By the way, the substrate holder 1 shown in FIG. 1 is mounted on the ZL stage 32, and on the stage main body 22, the Z drive unit 34 (driving means) for vertically moving the center-up member 10 within a predetermined range. ) And the center up member 1
There is provided a θ drive unit 36 for minutely rotating 0 at the center position of the substrate holder 1 (a θ drive unit for minutely rotating the substrate holder 1 on the ZL stage 32).

In FIG. 4, the center-up member 10 is in the most raised position by the Z drive portion 34, and the wafer W is suction-held on the upper end surface (on the annular convex portion 14) of the center-up member 10. At the center of the ZL stage 32, an opening having a size including at least the three-spoke through-holes 2A to 2C formed at the center of the substrate holder 1 is formed, and the center-up member 10 and the Z drive unit are formed. 34 are allowed to penetrate.

Further, FIG. 4 shows a load arm 40A and an unload arm 42A for vacuum-sucking the back surface of the wafer W and linearly transferring it in the Y direction. The load arm 40A and the unload arm 42A are arranged in a hierarchy at a predetermined interval (for example, twice or more the thickness of the wafer W) in the Z direction, and reciprocate in the Y direction by each independent drive system. They pass each other during the Y movement stroke.

Further, the height position of the wafer mounting surface (upper surface) of the load arm 40A is the height position P of the upper end surface when the center-up member 10 is most lifted as shown in FIG.
It is set lower than u (for example, about several mm),
As shown in FIG. 4, the height position of the back surface of the unload arm 42A opposite to the wafer mounting surface (upper surface) is slightly smaller than the height position Pd of the mounting surface 1A of the substrate holder 1 (for example, several mm). Degree) is set upward. As a result, when the center-up member 10 holds the wafer W and is most raised, the load arm 40A and the unload arm 42 are provided between the lifted wafer W and the upper surface of the substrate holder 1.
A space where both A can enter without contact is formed.

In the above-mentioned structure, the substrate holder 1 is provided in order to enhance the easiness of the cleaning work and the replacement work of the mounting surface 1A.
The ZL stage 32 can be easily removed and attached, and an example of the structure will be described with reference to FIG. FIG. 5 shows a partial cross section of the substrate holder 1 and the ZL stage 32. A part of the outer peripheral portion of the substrate holder 1 has positioning pins 32C (for example, 2 Positioning holes 1P (2 places) that engage with the (places) are formed.

On the holder mounting surface of the ZL stage 32,
Adsorption contact surface 1 formed at three places on the bottom surface of the substrate holder 1
Vacuum suction pads 32A, 32B, 3 that contact with each of S
2C (32C is not shown) is provided, and each pad 32
The upper end faces of A to 32C are machined so as to be as uniform as possible in the same plane. These pads 32A to 32C are connected to a vacuum source for attracting a holder via tubes 60A, 60C and the like and a solenoid valve 62.

When the substrate holder 1 is attached to the ZL stage 32, the substrate holder 1 is positioned and placed on the ZL stage 32 so that the positioning holes 1P penetrate the positioning pins 32C at a plurality of locations. At this time, since the upper end surfaces of the suction pads 32A to 32C come into close contact with the corresponding contact surfaces 1S at the bottom of the substrate holder 1, the solenoid valve 62 is subsequently opened to vacuum the substrate holder 1 onto the ZL stage 32. Adsorb.

In order to attract the wafer on the mounting surface 1A of the substrate holder 1, a connection mouthpiece 8C communicating with the suction groove or the suction hole of the mounting surface 1A is fixed to the bottom surface of the substrate holder 1, and ZL is attached. On the stage 32 side, a connection mouthpiece 32D is attached via a leaf spring 32E as an elastic urging member in such a position that it can be connected to the connection mouthpiece 8C. Therefore, when the substrate holder 1 is mounted on the ZL stage 32, the connection mouthpiece 32D biased upward by the leaf spring 32E is brought into pressure contact with the connection mouthpiece 8C to form a vacuum path.

When the wafer is sucked and held on the substrate holder 1, a vacuum pressure (for example, about 300 mmHg) is applied from the vacuum source for sucking the wafer to the mounting surface 1A through the tube 60B connected to the connection mouthpiece 32D and the electromagnetic valve 61. Supplied. Further, when the substrate holder 1 is removed from the ZL stage 32, the electromagnetic valve 61 cuts off the connection with the vacuum source and switches the tube 60B to open to the atmosphere, whereby the suction force at the suction pads 32A to 32C is rapidly increased. After turning off, the substrate holder 1 may be lifted.

As described above, since the substrate holder 1 is held on the ZL stage 32 by the vacuum suction force, the substrate holder 1 can be easily removed and attached, and when the tilted position of the ZL stage 32 is in the neutral state, the substrate holder 1 can be removed. The work of adjusting the parallelism between the mounting surface 1A and the best image forming surface of the projection optical system within an allowable range can be easily performed. Further, cleaning work of the mounting surface 1A of the substrate holder 1 (mainly peeling of resist, removal of fine particles)
Also in this case, since the entire substrate holder 1 can be removed from the ZL stage 32, there is an advantage that the work becomes easy.

By the way, the load arm 40A and the unload arm 42A shown in FIG. 4 are guided by a linear guide member extending from the housing side of the wafer loader mechanism arranged separately from the surface plate 20. Moves back and forth in the Y direction.
Therefore, a schematic configuration of the wafer loader mechanism will be briefly described with reference to FIG. FIG. 6 shows, for example, JP-A-7-24.
6 schematically shows a part of a wafer transfer device for a projection exposure apparatus disclosed in Japanese Patent No. 0366, and the stage body 22 shown in FIG. 4 is controlled by a laser interferometer and each linear motor. FIG. 6 is a perspective view showing a state in which the wafer is positioned at a wafer exchange position (loading position). At this time, the rotation center of the rotary table TT as the pre-alignment unit in the wafer loader mechanism WL and the stage body 22.
A line connecting the center point of the upper substrate holder 1 is set substantially parallel to the Y axis.

In FIG. 6, the same members as those of the stage mechanism shown in FIG. 4 are designated by the same reference numerals, and the upper end surface of the center-up member 10 located at the center of the substrate holder 1 is It is assumed that the substrate W is in a state of being slightly depressed (for example, about 1 to 2 mm) from the mounting surface 1A of the substrate holder 1, and the wafer W is vacuum-adsorbed on the mounting surface 1A of the substrate holder 1.

From the wafer loader mechanism WL, two parallel linear slide guide members 45, 46 are provided in parallel to the Y-axis toward the side of the substrate holder 1, of which the inner slide guide member 45 is A load side arm body 40C integrally supporting the load arm 40A shown in FIG. 4 is supported by a linear motor or the like not shown so as to be linearly movable in the Y direction, and the outer slide guide member 46 is shown in FIG. An unload-side arm body 42C that integrally supports the unload arm 42A is supported by a linear motor (not shown) or the like so as to be linearly movable in the Y direction.

As shown in FIG. 6, not only the load arm 40A but also the load arm 40A is attached to the load side arm body 40C in order to hold the back surface of the wafer by suction at two positions in the X direction.
A load arm 40B having a shape and arrangement symmetrical to that is fixed, and the unload-side arm main body 42C attracts and holds the back surface of the wafer at two positions in the X direction. The unload arm 42B having a symmetrical shape and arrangement is fixed. These load side arm body 40C and unload side arm body 4
2C is in a nested state with each other when viewed in the XZ plane.

Therefore, the arm body 40C (or 42C)
Since the wafer transferred by is held by the arms 40A, 40B (or 42A, 42B) at two positions on both sides with the central part sandwiched in the X direction without contacting the central part on the back surface thereof, For example, even if vacuum suction on the upper surfaces of the arms 40A, 40B (or 42A, 42B) becomes impossible due to a defect in the vacuum piping system or the like, the arm body 40
If the movement of C (42C) is stopped, the wafer will not fall from the arms 40A, 40B (or 42A, 42B), and the wafer can be safely protected.

In FIG. 6, the wafer loader mechanism W
The wafer W1 located at L is an unexposed wafer to be processed, and is rotated from the rotary table TT to the load arm 40.
The state immediately after being handed over to A and 40B is shown. Therefore, the rotary table TT has a mechanism for adsorbing the wafer W1 and rotating it by 360 ° or more for photoelectrically detecting and positioning the orientation flat or notch of the wafer W1, or after aligning the orientation flat or notch in a predetermined direction. A mechanism for lifting W1 to a position slightly above the upper surfaces of the load arms 40A and 40B is provided.

In the wafer loader mechanism WL as described above, the mounting planes defined by the upper surfaces of the load arms 40A, 40B and the mounting planes defined by the upper surfaces of the unload arms 42A, 42B rotate. It must be parallel to the upper end surface (holding surface) of the table TT, the mounting surface 1A of the substrate holder 1, and the upper end surface (holding surface) of the center-up member 10 with a predetermined accuracy.

Here, the wafer transfer operation will be briefly described. Here, as shown in FIG.
A single wafer W is adsorbed on the substrate holder 1, and the next unexposed wafer W1 is loaded onto the load arm 40 of the wafer loader mechanism WL.
The operation from the state of being sucked and held on A and 40B will be described. As shown in FIG. 6, the stage body 22
When the substrate is positioned at the loading position, the substrate holder 1
Immediately before the vacuum suction on the mounting surface 1A is released (for example, about several tens mS to several hundreds mS), the center-up member 10 starts to slowly rise by the Z drive mechanism 34, and its upper end surface (annular convex Vacuum suction at the portion 14) is started, and the upper end surface of the center-up member 10 comes into contact with the back surface of the wafer W.

Due to the contact, the center-up member 10
The signal of a pressure sensor (not shown) that detects the vacuum pressure at the upper end surface of the wafer changes, and when the signal reaches a specified value, it is determined that the center-up member 10 has sucked and held the wafer W, and the Z drive mechanism 34 determines the maximum. The center-up member 10 is lifted up to the raised position at high speed. If the signal from the pressure sensor does not change normally at this time, it is determined that a suction error has occurred, and the center-up member 10 is prohibited from further rising, and is returned to the lowest position for safety.

In this way, when the wafer W is lifted to the spatial position Pu above the substrate holder 1 as shown in FIG. 4, the unloading arm main body 42 waiting at the reset position is used.
C is guided by the outer guide member 46 and linearly moves in the direction of the substrate holder 1, and the unload arm 42 is moved in the Y direction.
A and 42B are positioned to the side of the raised center-up member 10.

When this positioning is completed, the vacuum suction (suction operation) on the upper surfaces of the unload arms 42A and 42B is started, and the center-up member 10 slowly begins to descend, and eventually the back surface of the wafer W is unloaded. Contact with the upper surfaces of 42A and 42B to start suction holding. At this time, whether or not the suction on the unload arms 42A and 42B is good or bad is confirmed by a pressure sensor (not shown), and when the reliable suction is confirmed, the vacuum suction on the upper end surface of the center-up member 10 is rapidly released. As a method of releasing the compressed air, a method of instantaneously supplying compressed air to a suction hole for vacuum suction via an electromagnetic valve or the like can be considered.

With the above operation, the upper end surface of the center-up member 10 and the back surface of the wafer W are separated from each other during the descent, so that the unload arms 42A and 42B are completely depressed by the center-up member 10 into the substrate holder 1. Before that, the linear movement of the wafer loader mechanism WL toward the rotary table TT is started. Almost at the same time, the loading arm main body 40C positioned as shown in FIG. 6 starts linear movement toward the substrate holder 1.

As a result, the unload arms 42A, 42B holding the exposed wafer W and the load arms 40A, 40B holding the unexposed wafer W1 pass each other in the middle of the movement stroke of the slider guide members 45, 46. . In the case of the present embodiment, the unexposed wafer W1 is determined so that the upper side of the unexposed wafer W1 and the lower side of the exposed wafer W due to the passing, and microscopic dust from the exposed wafer W falls on the unexposed wafer W1. It is configured not to.

When the unexposed wafer W1 is transferred to the space above the substrate holder 1 by the load arms 40A and 40B in this way, the center-up member 10 starts to move upward while performing the vacuum suction operation again, and is held by the load arms 40A and 40B. It comes into contact with the back surface of the unexposed wafer W1 thus formed. At this time, the pressure sensor confirms the suction of the wafer W1 by the center-up member 10, and the load arm 40A,
The adsorption by 40B is rapidly released.

As a result, the wafer W1 is lifted by the center-up member 10 to a position Pu slightly elevated (for example, 1 to several mm) from the upper surfaces of the load arms 40A and 40B, and the load arms 40A and 40B are accordingly moved.
When the pressure sensor that detects the adsorption of the wafer W1 confirms the release of the wafer W1, the load arms 40A and 40B retract from the lower space of the unexposed wafer W1 to the same reset position as the unload arms 42A and 42B shown in FIG. .

Finally, the center-up member 10 starts to descend slowly while holding the unexposed wafer W1 by suction at its upper end surface, and the vacuum suction operation on the mounting surface 1A of the substrate holder 1 is started, so that the unexposed wafer W1 is unexposed. Wafer W1 is mounting surface 1
At the same time when the contact with A is started and the suction is started, the suction at the center-up member 10 is rapidly released. At this time, the suction of the wafer W1 on the substrate holder 1 is confirmed in parallel by a pressure sensor (not shown), and after the confirmation, the stage main body 22 (and the unexposed wafer W1) is subjected to wafer alignment (mainly wafer alignment) as an exposure preparation operation. It moves in the XY directions for the position detection operation of the upper alignment mark).

The center-up member 10 described above is used.
Arranging the three spoke-shaped mounting portions 11A to 11C at equal lengths from the center and arranged at an angular interval of 120 °, but it is not limited to this, and two spoke-shaped mounting portions are provided. It can be appropriately selected within a range of about 5 to 5.

For example, when two spoke-shaped mounting portions are provided, the bending angle thereof is set to about 90 °, and the shaft portion 13 connected at the bending point is slightly decentered from the center C0 of the substrate holder 1. You may make it arrange | position.
In this case, the through hole or the recessed portion on the substrate holder 1 side where the two spoke-shaped mounting portions sink can be formed substantially at the center of the substrate holder 1 due to the eccentricity of the shaft portion 13, and thus the through hole or the recessed portion can be formed. The center of gravity of the substrate can be set in the inner region sandwiched by the two spoke-shaped mounting portions bent at 90 °.

When the number of spoke-shaped mounting portions is four or more, the width of each spoke-shaped mounting portion in the circumferential direction is a value smaller than the numerical value exemplified in the above embodiment, for example, 3 to 4 mm.
However, this does not reduce the substrate suction force on the entire upper end surface of the spoke-shaped mounting portion. Further, the width of each spoke portion of the petal-type through hole or the recess formed on the substrate holder 1 can be reduced correspondingly.

The wafer transfer load arms 40A and 40B and the unload arms 42A and 42B shown in FIG.
Although the rear surface of the wafer is arranged so as to be held from both sides, it may be an arm that vacuum-adsorbs the rear surface of the wafer only on one side that is eccentric from the central portion of the wafer. It may be a type.

Further, instead of using the linear motion type transfer arm for transferring the substrate from the pre-alignment unit to the substrate holder, a system in which all the substrates are transferred by an articulated robot arm may be used. In this case, within the carrier,
Alternatively, the substrate stored in the in-line stock section is the robot arm and the rotary table TT of the pre-alignment section.
The pre-aligned substrate transferred to the substrate holder 1 is again transferred onto the substrate holder 1 by the robot arm.

Next, some modified examples of the center-up portion will be described.

FIG. 7 is a perspective view showing a first modification of the center-up member. This center-up member includes the base portions 12A to 12C of the three spoke portions 11A to 11C.
The annular protrusions 14A to 14C for adsorbing the back surface of the wafer are individually provided near the tip of the upper part of the above, and suction holes are formed inside the annular protrusions 14A to 14C. As a measure against static electricity, the outer side surface of each annular convex portion 14A to 14C is formed flat by polishing, and the conductive tape 17 is attached so as to straddle the polished surface and the pedestal portions 12A to 12C. It is similar to the center-up member 10 shown in FIGS. 2 and 3.

FIG. 8 is a perspective view showing a second modification of the center-up member. The center-up member includes spoke-shaped pedestal portions 12A and 12B extending from the shaft portion 13 in the left-right direction (X direction), and an arc-shaped pedestal portion having concentric outer shapes fixed to the tips of the pedestal portions 12A and 12B. 12
A ′ and 12B ′, and the shaft portion 13, the spoke-shaped pedestal portions 12A and 12B, and the arc-shaped pedestal portions 12A ′ and 1
This is a structure in which an annular convex portion 14 for defining a concave portion for vacuum suction is provided on each upper end surface of 2B '. As a measure against static electricity,
The outer side surface of the annular convex portion 14 is flattened by polishing, and the polishing surface and the pedestal portions 12A to 12 are formed.
As in the center-up member 10 shown in FIGS. 2 and 3, the conductive tape 17 is attached so as to straddle C.

Although not shown, the present invention is
The present invention can also be applied to a substrate holding device including a conventionally used 3-pin type center-up member.
The three-pin type center-up member is provided with three pin members that hold the wafer at three places, and each pin member is bonded and fixed to the pipe-shaped pedestal made of metal and its tip with an adhesive. And an annular convex portion (cylindrical member). The three pin members are fixed to a plate or the like at the bottom of each, and by moving the plate up and down,
The tip portion of each pin member can be set to a position where it is buried or protruded from the substrate holder. The wafer is held by suctioning the inside of the pin under negative pressure in a state where the tip of the annular convex portion is brought into contact with the back surface of the wafer. As a measure against static electricity, a polishing surface is formed by polishing the outer side surface of the annular convex portion, and the conductive tape is attached so as to extend between the polishing surface and the pedestal part. 2 and the center up member 10 shown in FIG. The center-up member 10 may be a single pin type.

In the above-described embodiment, a large circular wafer of about 300 mm is specifically targeted for holding, but the same can be applied to the case where the substrate to be suction-held is rectangular.

Further, the center-up member 10 is premised on that the upper end surface of the center-up member 10 sucks and holds the substrate, but vacuum suction is not always necessary depending on the applied device.
In particular, in an electron beam exposure apparatus or a dry etching apparatus that holds and conveys a substrate to be processed in a vacuum atmosphere, since vacuum adsorption by the center-up member 10 is impossible, they support the substrate only by its own weight. .

Further, although the center-up member 10 is moved up and down when the wafer is loaded or unloaded in the above-described embodiment, the substrate holder 1 may be moved up and down instead of the center-up member 10. At least one of the up member 10 and the substrate holder 1 may be moved up and down.

Further, in the above-mentioned embodiment, the annular convex portion 14
Although DLC, TiC, TiN, etc. are used as the coating material for the above, the material capable of forming a film with a surface roughness that does not cause unstable conduction, for example, DLC, TiN, etc., has a thickness of about several to several tens of μm. Since a film is formed and the surface roughness thereof is approximately the same as that of the above-mentioned polished surface, sufficient conduction can be obtained without polishing the portion to which the conductive member is attached. Therefore, in the present invention, it is not always necessary to polish the portion to which the conductive member is attached, and the necessity of polishing may be determined according to the type of coating material.

As an exposure apparatus to which the substrate holding apparatus according to the present invention is applied, not only a scanning type exposure apparatus for synchronously moving the mask and the substrate to expose and transfer the pattern of the mask but also the mask and the substrate are stationary. The pattern of the mask is exposed and transferred in this state, and the pattern of the mask is exposed and transferred by bringing the mask and the substrate into close contact with each other without using a step-and-repeat type exposure apparatus that sequentially moves the substrate or a projection optical system. There is a proximity exposure device.

The application of the exposure apparatus is not limited to the exposure apparatus for manufacturing a semiconductor device. For example, an exposure apparatus for liquid crystal for exposing and transferring a liquid crystal display element pattern onto a rectangular glass plate, a thin film exposure apparatus. It can be widely applied to an exposure apparatus for manufacturing a magnetic head. Further, it can be applied to an exposure apparatus for manufacturing a micromachine, a DNA chip, a mask and the like. As the light source of the exposure apparatus, in addition to the KrF excimer laser (wavelength 248 nm),
g line (wavelength 436 nm), i line (wavelength 365 nm), A
An rF excimer laser (wavelength 193 nm) and an F ₂ laser (wavelength 157 nm) can be used. Furthermore, X
A charged particle beam such as a beam or an electron beam can also be used. For example, when an electron beam is used, thermionic emission type lanthanum hexaboride (LaB ₆ ) or tantalum (Ta) can be used as the electron gun.

The projection optical system in the projection type exposure apparatus may be not only a reduction system but also a unity magnification system and an enlargement system. As the projection optical system, a material that transmits far ultraviolet rays such as quartz or fluorite is used as a glass material when using far ultraviolet rays such as excimer laser, and a catadioptric system or a refraction system when using F ₂ laser or X-ray. An optical system is used (a reticle of a reflection type is also used), and when an electron beam is used, an electron optical system including an electron lens and a deflector is used as the optical system. Needless to say, the optical path through which the electron beam passes is placed in a vacuum state.

In the above-described embodiment, the case where the present invention is applied to the center-up member as a transfer device for transferring the substrate (wafer) to the substrate holder has been described, but the present invention is not limited to this. However, the substrate holding device used in the carrying device for delivering the substrate to the center-up member, the substrate holding device used in the pre-alignment mechanism, the carrying device for carrying the substrate to the pre-alignment mechanism, etc. The present invention can be applied to any substrate holding device that holds a substrate in the exposure apparatus.

For semiconductor devices, generally, a step of designing the function / performance of the device, a step of producing a reticle based on this design step, a step of producing a wafer from a silicon material, and an exposure apparatus inline with a coater are used. It is manufactured through the steps of exposing and transferring the reticle pattern onto a resist-coated wafer, developing the device, assembling the device (including the dicing process, bonding process, and packaging process), and inspecting the process. Is required
The present invention is widely applicable to devices used in the step of handling those wafers.

It is needless to say that the present invention is not limited to the above-mentioned embodiment and can be variously modified within the scope of the present invention.

[0091]

According to the present invention, it becomes possible to reliably discharge the static electricity generated by holding the substrate, and to prevent the obstacle caused by the transportation of the substrate caused by the static electricity and the obstacle caused by adsorption of dust and the like. It is possible to suppress the generation, and it is possible to manufacture high-quality, high-performance microdevices and the like.

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic overall configuration of a substrate holding device according to the present invention.

FIG. 2 is a perspective view showing a schematic overall configuration of a spoke-shaped center-up member shown in FIG.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a cross-sectional view showing an overall configuration of an XY stage for a projection exposure apparatus in which the substrate holding device of FIG. 1 is mounted.

5 is a cross-sectional view illustrating a structure for mounting the substrate holder shown in FIG. 4 on an XY stage.

6 is a perspective view showing a schematic overall configuration of a wafer loader mechanism of a projection type exposure apparatus to which the XY stage of FIG. 4 is applied.

FIG. 7 is a perspective view showing a first modification of the center-up member.

FIG. 8 is a perspective view showing a second modification of the center-up member.

[Explanation of symbols] 1 ... Substrate holder (Substrate holding device) 10 ... Center up member (substrate holding device) 11A to 11C ... Spoke-shaped mounting portion 12A to 12C ... Pedestal part (pedestal member) 13 ... Shaft 14, 14A to 14C ... Annular convex portion (holding member) 15 ... Suction hole 17 ... Conductive tape (conductive member) 22 ... Stage body 32 ... ZL stage

Claims (8)

[Claims] 1. A holding member made of a non-metallic material, which abuts a part of the back surface of the substrate to hold the substrate, and a pedestal member made of a metallic material, the holding member being adhesively fixed to a tip end portion of the holding member, A substrate comprising: a holding member and a flexible conductive member attached across the pedestal member, wherein at least a portion of the holding member to which the conductive member is attached is ground. Holding device. 2. A substrate holder having a substrate mounting surface that comes into contact with the back surface of the substrate, a holding member made of a non-metallic material that comes into contact with part of the back surface of the substrate, and the holding member bonded and fixed to the tip portion thereof. A pedestal member made of a metal material, a conductive member having flexibility attached to the holding member and the pedestal member, and a contact portion of the holding member with respect to the substrate is the substrate mounting surface. And a drive means for relatively moving the pedestal member and the substrate holder so as to be set at a position buried from the substrate mounting position and a position protruding from the substrate mounting surface, and the conductive member of the holding member is attached. A substrate holding device characterized in that a portion to be polished is polished. 3. A substrate holder having a substrate mounting surface that contacts the back surface of the substrate, a holding member that contacts part of the back surface of the substrate, and a tip portion of the holding member in an electrically insulated state. A substrate holding device comprising: a pedestal member fixed to a substrate; a conductive member that electrically connects the holding member and the pedestal member; and a drive unit that relatively moves the substrate holder and the pedestal member. . 4. The conductive member is attached to the holding member and the pedestal member.
The substrate holding device according to. 5. The substrate according to claim 4, wherein when a thin film that deteriorates conductivity is formed on a portion of the holding member to which the conductive member is attached, the portion is polished. Holding device. 6. The substrate holding device according to claim 4, wherein the holding member is coated with a material capable of forming a film with a surface roughness that does not cause unstable conduction. 7. The substrate holder of at least a base material is made of low thermal expansion ceramics, and the substrate holder and the pedestal member are grounded, respectively. Substrate holding device according to item. 8. An exposure apparatus comprising the substrate holding device according to any one of claims 1 to 7.