JP2005064351A - Holder, exposure device having the holder, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a holder which reduces deformation caused when a substrate is sucked, in particular, deformation of an outer periphery of the substrate to prevent positional displacement, and also to provide an exposure device having the holder, and a device manufacturing method. <P>SOLUTION: The holder for holding a predetermined substrate has a plurality of projections for sucking the predetermined substrate via a suction surface prescribing a reference surface for alignment of the predetermined substrate. The plurality of projections have an equal sucking force and are arranged so that a sucking density is increased toward the radial direction of the reference surface from the circumferential direction thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In general, an exposure apparatus used in a lithography process for manufacturing a precision device on which an optical member is mounted, particularly a semiconductor element, an imaging element (CCD, etc.) or a thin film magnetic head, etc. The present invention relates to a holding device for obtaining a more accurate imaging relationship when projecting and exposing an image of a reticle or a mask onto an object to be processed (for example, a single crystal substrate for a semiconductor wafer or a glass substrate for a liquid crystal display (LCD)). . The present invention is particularly suitable for holding a reticle, a wafer, or the like in an exposure apparatus that uses ultraviolet light or extreme ultraviolet (EUV) light as exposure light.

  When manufacturing fine semiconductor elements such as semiconductor memories and logic circuits using photolithography (baking) technology, a circuit pattern drawn on a reticle (or mask) is projected onto a wafer or the like by a projection optical system. A reduction projection exposure apparatus for transferring the image has been used conventionally.

  The minimum dimension (resolution) that can be transferred by the reduction projection exposure apparatus is proportional to the wavelength of light used for exposure and inversely proportional to the numerical aperture (NA) of the projection optical system. Therefore, the shorter the wavelength, the better the resolution. For this reason, in response to the recent demand for miniaturization of semiconductor elements, the exposure light has been shortened, and an ultra-high pressure mercury lamp (i-line (wavelength: about 365 nm)), KrF excimer laser (wavelength: about 248 nm), ArF excimer. The wavelength of ultraviolet light used with lasers (wavelength about 193 nm) has become shorter.

  However, semiconductor elements are rapidly miniaturized, and there is a limit in lithography using ultraviolet light. Therefore, in order to efficiently transfer a very fine circuit pattern of 0.1 μm or less, a reduction projection exposure apparatus using extreme ultraviolet (EUV) light having a wavelength shorter than that of ultraviolet light and having a wavelength of about 10 nm to 15 nm ( Hereinafter, it is referred to as “EUV exposure apparatus”).

Since the EUV exposure apparatus is used for exposure of a circuit pattern of 0.1 μm or less, it is required to hold the surface shape of the reticle or wafer with very high accuracy (ie, flatness). Accordingly, a hyperbolic electrostatic chuck having two electrodes is used to hold the reticle and wafer flat by electrostatic attraction, so that an optimal imaging position is always maintained during exposure (for example, patents). Reference 1).
Japanese Patent Laid-Open No. 9-306834

  However, as shown in FIG. 9, the electrostatic chuck used for holding the reticle and the wafer sandwiches particles (dust) PT between the substrate 1000 such as the reticle or wafer and the electrostatic chuck 2000, and thus the substrate 1000. May be distorted in the Y direction. Accordingly, since the local warpage amount of the substrate 1000 changes by θ, the position before the particle PT is sandwiched is Lr, the position that is changed because the particle PT is sandwiched is Lm, and the thickness of the substrate 1000 is t. The surface of the substrate 1000 causes a positional deviation ΔL expressed by the following formula 1, which causes deterioration in transfer accuracy. Here, FIG. 9A is a schematic cross-sectional view showing the substrate 1000 in which the positional deviation of the surface has occurred due to a local change in the amount of warpage, and FIG. 9B is a schematic cross-sectional view of FIG. It is an expanded sectional view of (alpha) part shown in FIG.

例えば、基板をウェハとして考えてみると、ウェハと静電チャックとの間にパーティクルを挟み込むことで０．１μｍのＹ方向への変形量が生じた場合、θ変化が大きく、５ｎｍ程度のＸ方向の位置ずれを生じてしまう。

For example, when the substrate is considered as a wafer, if the amount of deformation in the Y direction of 0.1 μm is caused by sandwiching particles between the wafer and the electrostatic chuck, the θ change is large and the X direction is about 5 nm. Misalignment will occur.

  Therefore, an electrostatic chuck (pin chuck or ring chuck) has been proposed in which the entire surface of the substrate is not attracted but the contact area with the substrate is reduced to reduce the probability of sandwiching particles. Such an electrostatic chuck causes the back surface of the substrate to be aligned with a reference surface defined by the upper end surfaces of a plurality of convex portions (pins) formed on the chuck surface, and generates a suction force due to static electricity on the convex portion. To adsorb. Further, in order to further reduce the contact area between the substrate and the chuck, it is conceivable to reduce the area of the tip of the convex portion or to increase the interval (pitch) between the convex portions.

  As shown in FIG. 10A, the back surface 1000b of the substrate 1000 generally has a larger surface roughness than the front surface 1000a. Therefore, considering the case where the position of the arrow CF is attracted by the pin 2100 having a reduced tip area, the height of the substrate 1000 (the back surface 1000b) supported by the pin 2100 differs depending on the roughness of the back surface 1000b. However, since the height of the pin 2100 is constant, as shown in FIG. 10B, a local warp occurs on the surface 1000a of the substrate 1000 after the suction, leading to deterioration in transfer accuracy. . Here, FIG. 10A is a schematic cross-sectional view of the substrate 1000 having a surface roughness on the back surface 1000b, and FIG. 10B shows a local warpage due to the surface roughness of the back surface 1000b. It is a schematic sectional drawing which shows the board | substrate 1000 which carried out.

  Further, as shown in FIG. 11, the substrate 1000 </ b> A may be warped in the outer peripheral portion with respect to the central portion due to the stress of the pattern formed through the process. For example, in a wafer having a diameter of about 300 mm, a warp of about 100 nm at the maximum occurs when a resist is applied after the process and loaded into an exposure apparatus. Here, FIG. 11 is a schematic cross-sectional view of the substrate 1000A in which the outer peripheral portion is warped with respect to the central portion.

  12A and 12B are schematic views showing a case where a substrate 1000A having a warped outer periphery is sucked by a pin chuck, wherein FIG. 12A is a plan view and FIG. 12B is a diagram shown in FIG. It is AA 'sectional drawing. Referring to FIG. 12, the concave portion 1100 and the convex portion 1200 are formed in the outer peripheral portion of the substrate 1000A. In particular, when the interval between the pins 2100 is increased, the concave portion 1100 and the convex portion 1200 become larger.

  The amount of unevenness of the concave portion and the convex portion generated in the outer peripheral portion of the substrate may be reproducible. However, the amount of warpage of the substrate varies depending on the stress of the pattern to be formed, and thus the amount of unevenness varies depending on the substrate. In this case, although the change in θ is small on the surface of the substrate, a positional shift represented by Formula 1 occurs as described above. For example, when there is a deformation in the Y direction of about 20 nm, a positional deviation in the X direction of about 1.6 nm occurs.

  Accordingly, the present invention provides a holding device that can prevent deformation caused by sucking the substrate, in particular, deformation at the outer peripheral portion of the substrate to prevent displacement, an exposure apparatus having such a holding device, and It is an exemplary object to provide a device manufacturing method.

  In order to achieve the above object, a holding device according to one aspect of the present invention is a holding device that holds a predetermined substrate, wherein the holding device defines a reference surface that controls the predetermined substrate. The plurality of convex portions adsorbing a predetermined substrate, each of the plurality of convex portions has an equal adsorption force, and is arranged so that the adsorption density is larger in the radial direction than the circumferential direction of the reference surface. It is characterized by that.

  A holding device according to another aspect of the present invention is a holding device for holding a predetermined substrate, and the holding device has a suction surface having a diameter of 0.1 mm or more that defines a reference surface for aligning the predetermined substrate. A plurality of protrusions for adsorbing a predetermined substrate, wherein the plurality of protrusions has a total area of the adsorption surface of 10% or less with respect to the area of the predetermined substrate; The density is larger in the radial direction than in the circumferential direction of the reference surface.

  A holding device according to still another aspect of the present invention is a holding device that holds a predetermined substrate, and sucks the predetermined substrate through a suction surface that defines a reference surface that aligns the predetermined substrate. It has a plurality of ring-shaped convex portions, and the intervals between the plurality of ring-shaped convex portions in the radial direction of the reference surface become smaller as the distance from the center of the reference surface increases.

  An exposure apparatus according to still another aspect of the present invention exposes an object to be processed by irradiating the object to be processed held by the holding device with a light beam emitted from a light source via a projection optical system. Features.

  An exposure apparatus according to yet another aspect of the present invention illuminates a reticle on which a desired pattern held by the above-described holding device is formed using a light beam emitted from a light source, and the desired pattern is irradiated on the object to be processed. It is characterized by exposing to the following.

  An exposure apparatus according to still another aspect of the present invention includes the holding device described above.

  According to still another aspect of the present invention, there is provided a device manufacturing method comprising: exposing a target object using the exposure apparatus described above; and performing a predetermined process on the exposed target object. And

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, a holder that can reduce deformation that occurs when adsorbing a substrate, in particular, deformation at the outer peripheral portion of the substrate to prevent misalignment, an exposure apparatus that includes such a holder, and A device manufacturing method can be provided.

  First, the inventor returns to the basics to provide a holding device that can prevent deformation caused by adsorbing the substrate, in particular, deformation at the outer peripheral portion of the substrate to prevent misalignment. As a result of intensive studies on the deformation (strain) that occurs when a substrate with warpage caused by suction is attracted by a pin chuck, it has been found that the deformation is a wave-deformed deformation in the radial direction of the reference surface defined by the pin chuck.

  Therefore, the present inventor can reduce the deformation of the substrate, in particular, the deformation at the outer peripheral portion of the substrate and prevent the positional deviation by giving a large amount of adsorption force to the substrate in the radial direction of the reference surface. I found it.

  Hereinafter, a holding device which is an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, about the same member, the same reference number is attached | subjected and the overlapping description is abbreviate | omitted. Here, FIG. 1 is a schematic sectional view showing the configuration of the holding device 100 of the present invention.

  The holding device 100 is embodied as, for example, an electrostatic holding type pin chuck that generates a larger electrostatic attraction force at the convex portion (attraction pin) of the chuck, and holds the substrate. As shown in FIG. 1, the holding device 100 applies a voltage to the electrode 140 to give a potential difference between the chuck 110 and a predetermined substrate PS, and the electrostatic force generated on the suction pin 120 by the potential difference causes a predetermined difference. The substrate PS is adsorbed to the chuck 110. Examples of the predetermined substrate PS include a wafer on which a desired pattern is transferred, a reticle on which a desired pattern to be transferred to the wafer is formed, and the like.

  The chuck 110 has a plurality of suction pins 120. The suction pin 120 is formed on the surface of the chuck 110 by sandblasting and polishing. The suction pin 120 has a suction surface 122 that defines a reference surface BP on which the predetermined substrate PS is arranged at the upper end, and sucks the predetermined substrate PS through the suction surface 122.

The suction pin 120 has a total area of the suction surface 122 (that is, the total area of the suction surfaces 122 of the plurality of suction pins 120) of 10% or less with respect to the area of the predetermined substrate PS, and the diameter of the suction surface 122 is smaller. It is formed to be 0.1 mm or more. Accordingly, the probability of sandwiching particles (dust) between the predetermined substrate PS and the chuck 110 can be reduced, and deterioration of transfer accuracy due to deformation of the predetermined substrate PS can be prevented. In the present embodiment, the suction pins 120 have a surface area of one suction surface 122 of about 10 mm ^{2 and} a center interval between the suction surfaces 122, ie, a so-called pin interval of about 10 mm.

  As described above, the deformation that occurs when the substrate that has warped due to stress is corrected by the reference plane BP is a deformation that waves in the radial direction of the reference plane BP. By arranging so as to give a large suction force in the radial direction of the surface BP, deformation at the outer peripheral portion of the predetermined substrate PS can be reduced. In other words, the plurality of suction pins 120 are arranged such that the suction density is larger in the radial direction than in the circumferential direction of the reference plane BP. Specifically, it is preferable to configure the suction density in the radial direction of the reference surface BP to be 1.5 to 5 times the suction density in the circumferential direction.

FIG. 2 is a schematic plan view showing an example of the arrangement of the suction pins 120 on the surface of the chuck 110 shown in FIG. Referring to FIG. 2, the plurality of suction pins 120 are arranged such that the spacing (pitch) between the suction pins 120 is more radial than the circumferential pitch at the outer peripheral portion BPO of the reference surface BP (ie, the outer peripheral portion of the chuck 110). The pitch is arranged to be shorter. In particular, any adsorption pins 120a and the center of any of the suction pin 120a and the reference plane BP (i.e., the center of the chuck 110) O and shortest adsorption pins perpendicular _{Q 1} to _{Q 3} drawn to a line P connecting the distance _{L 1} and 120b are arranged so as to be smaller than the distance _{L 2} between the shortest adsorption pin 120c is perpendicular _{T 1} to _{T 3} drawn to a tangent R concentric S through any suction pin 120a ing. As a result, a large suction force can be applied in the radial direction of the reference surface BP, and deformation of a predetermined substrate PS, particularly deformation at the outer peripheral portion of the substrate PS can be reduced, thereby preventing misalignment. In the present embodiment, the deformation in the Y direction, which has conventionally been about ± 20 nm, is reduced to about ± 5 nm or less, so that the positional deviation in the X direction is reduced to a negligible level, and the transfer accuracy is improved. It was.

  Further, the arrangement of the plurality of suction pins 120 may be as shown in FIG. Here, FIG. 3 is a schematic plan view showing another example of the arrangement of the suction pins 120 on the surface of the chuck 110 shown in FIG. Referring to FIG. 3, the chuck 110 includes a ring-shaped suction pin 120 </ b> A continuously arranged in the circumferential direction of the reference surface BP at the outer peripheral portion BPO of the reference surface BP (that is, the outer peripheral portion of the chuck 110). A suction pin 120B disposed inside the ring-shaped suction pin 120A. In addition, the arrangement relationship between the ring-shaped suction pins 120A and the suction pins 120B is determined by changing the distance (pitch) in the radial direction of the reference surface BP between the suction pins 120A and 120B as shown by arrows in FIG. It is made narrower than the interval in the radial direction of the reference plane BP of 120B.

In other words, the suction pins 120A arranged in a ring shape continuous in the circumferential direction of the reference plane BP constitute the first suction pin group PC1 and are distributed and arranged inside the first suction pin group PC1. The suction pins 120B constitute a second suction pin group PC2.
Further, among the second adsorption pin group PC2, the outermost adsorbed pins 120B _O of the first adsorption pin group PC1 side, the distance _{L 4} between the first adsorption pin group PC1 is, the outermost suction pin 120B _O is perpendicular U ₁ to U ₃ drawn tangentially R concentric S are arranged so as to be smaller than the distance L ₅ between the shortest adsorption pin 120B _S through.

  With such an arrangement, a large amount of attracting force is given in the radial direction of the reference surface BP, and deformation of a predetermined substrate PS, particularly deformation at the outer peripheral portion of the substrate PS can be reduced, thereby preventing misalignment. .

  Hereinafter, with reference to FIG. 4, a holding device 100 </ b> A that is a modification of the holding device 100 will be described. Similar to the holding device 100, the holding device 100A is an electrostatic holding type pin chuck that can apply a large amount of suction force in the radial direction of the reference surface BP.

  As shown in FIG. 4, a plurality of suction pins 160 are formed on the surface of the chuck 110 by sandblasting and polishing. The suction pin 160 has a suction surface 162 that defines a reference surface BP on which a predetermined substrate is arranged at the upper end, and sucks the predetermined substrate through the suction surface 162. Here, FIG. 4 is a schematic plan view showing the surface of the chuck 110 of the holding device 100A of the present invention.

  The suction pin 160 has a total area of the suction surface 162 (that is, the total area of the plurality of suction pins 160) of 10% or less and a diameter of the suction surface 162 of 0.1 mm or more with respect to a predetermined substrate area. Formed to be. Thereby, the probability of sandwiching particles (dust) between the predetermined substrate and the chuck 110 can be reduced, and deterioration of transfer accuracy due to deformation of the predetermined substrate can be prevented.

  As described above, the deformation that occurs when the substrate that has been warped due to stress is corrected by the reference surface BP is a waveform that waves in the radial direction of the reference surface BP. By making 162 a shape that gives a large suction force in the radial direction of the reference plane BP, deformation at the outer peripheral portion of a predetermined substrate can be reduced. In other words, the plurality of suction pins 160 have a shape such that the suction density is larger in the radial direction than the circumferential direction of the reference surface BP. Specifically, the shape of the suction surface 162 of the suction pin 160 is preferably such that the suction density in the radial direction of the reference surface BP is 1.5 to 5 times the suction density in the circumferential direction.

Referring to FIG. 4, a plurality of suction pin 160, the center of the reference plane BP (i.e., the center of the chuck 110) is disposed radially from O, in the radial direction of the reference plane BP length K ₁ is the reference plane BP having a suction surface 162 of the circumferential direction of the longer shape than the length K _2. In this embodiment, suction surface 162 of the suction pin 160, the radial length K ₁ of the reference plane BP with respect to the circumferential direction of the length K ₂ of the reference plane BP is three-fold. Incidentally, the radial length K ₁ of the reference plane BP with respect to the circumferential direction of the length K ₂ of the reference plane BP is preferably set to be 1.5 times to 5 times.

As a result, a large amount of adsorption force can be applied in the radial direction of the reference surface BP, and deformation of a predetermined substrate, in particular, deformation at the outer peripheral portion of the substrate can be reduced and misalignment can be prevented. In the present embodiment, the deformation in the Y direction, which has conventionally been about ± 20 nm, is reduced to about ± 5 nm or less, so that the positional deviation in the X direction is reduced to a negligible level, and the transfer accuracy is improved. It was. In the case of adsorption pins circumferential length K ₂ of the reference plane BP has a suction surface of the elongated than the radial length K ₁ in the reference plane BP is deformed in the Y direction + 5 nm to -20nm next Experiments have shown that the improvement effect is small.

  Hereinafter, a holding device 100B, which is a modification of the holding device 100, will be described with reference to FIG. Similar to the holding device 100, the holding device 100B is an electrostatic holding type ring chuck that can apply a large amount of suction force in the radial direction of the reference surface BP, but is different with respect to the suction pin 170.

  As shown in FIG. 5, a plurality of suction pins 170 are formed in a continuous ring shape in the circumferential direction of the reference surface BP on the surface of the chuck 110 by sand blasting and polishing. The ring-shaped suction pin 170 has a suction surface 172 that defines a reference surface BP on which a predetermined substrate is arranged at the upper end, and sucks the predetermined substrate through the suction surface 172. Here, FIG. 5 is a schematic plan view showing the surface of the chuck 110 of the holding device 100B of the present invention.

  The suction pin 170 has a total area of the suction surface 172 (that is, a total area of the plurality of suction pins 170) of 10% or less and a diameter of the suction surface 172 of 0.1 mm or more with respect to an area of a predetermined substrate. Formed to be. Thereby, the probability of sandwiching particles (dust) between the predetermined substrate and the chuck 110 can be reduced, and deterioration of transfer accuracy due to deformation of the predetermined substrate can be prevented.

  As described above, the deformation that occurs when the substrate that has warped due to stress is corrected by the reference plane BP is a waveform that waves in the radial direction of the reference plane BP. Is arranged so as to give a large adsorption force in the radial direction of the reference plane BP, it is possible to reduce deformation at the outer peripheral portion of the predetermined substrate. In other words, the plurality of suction pins 170 are arranged such that the suction density is larger in the radial direction than in the circumferential direction of the reference plane BP. Specifically, it is preferable to configure the suction density in the radial direction of the reference surface BP to be 1.5 to 5 times the suction density in the circumferential direction.

Referring to FIG. 5, the plurality of ring-shaped suction pins 170 are concentric from the center O of the reference surface BP (that is, the center of the chuck 110) and in the radial direction of the reference surface BP, It arrange | positions so that a space | interval may become so small that it leaves | separates from. That is, if the suction pins 170a, 170b, 170c, 170d, and 170e are separated from the center O of the reference plane, the distance M ₁ between the suction pins 170a and 170b and the distance M between the suction pins 170b and 170c. _2, the suction pin 170c and the distance _{M 3} between the suction pin 170d, the distance _{M 4} of the suction pin 170d and the suction pin 170e, satisfy the relation represented by the following equation 2.

リング状の複数の吸着ピン１７０をこのように配置することにより、基準面ＢＰの径方向に多くの吸着力を与えることができ、所定の基板の変形、特に、基板の外周部での変形を低減し、位置ずれを防止することができる。

By arranging the plurality of ring-shaped suction pins 170 in this manner, a large amount of suction force can be applied in the radial direction of the reference surface BP, and deformation of a predetermined substrate, particularly, deformation at the outer peripheral portion of the substrate can be performed. It is possible to reduce and prevent misalignment.

  As described above, instead of reducing the surface area of the suction surface of the suction pin, the contact area between the substrate and the chuck is reduced by the placement of the suction pin and the shape of the suction surface, and the warped substrate is sucked. Since deformation of the substrate that occurs sometimes can be reduced, it is possible to prevent deterioration in transfer accuracy due to the roughness of the substrate to be held.

  Hereinafter, an exemplary exposure apparatus 500 to which the holding apparatus 100 of the present invention is applied will be described with reference to FIG. Here, FIG. 6 is a schematic optical path diagram showing an exemplary exposure apparatus 500 of the present invention.

  The exposure apparatus 500 of the present invention is formed on the reticle 520 by using, for example, a step-and-scan method or a step-and-repeat method using EUV light (for example, a wavelength of 13.4 nm) as exposure illumination light. This is a projection exposure apparatus that exposes a circuit pattern to a workpiece 540. Such an exposure apparatus is suitable for a lithography process of submicron or quarter micron or less, and in the present embodiment, a step-and-scan type exposure apparatus (also referred to as “scanner”) will be described as an example. Here, the “step and scan method” means that the wafer is continuously scanned (scanned) with respect to the reticle to expose the reticle pattern onto the wafer, and the wafer is stepped after completion of one shot of exposure. The exposure method moves to the next exposure area. The “step-and-repeat method” is an exposure method in which the wafer is stepped and moved to the exposure area of the next shot for every batch exposure of the wafer.

  Referring to FIG. 6, exposure apparatus 500 mounts illumination apparatus 510, reticle 520, reticle stage 525 on which reticle 520 is mounted, projection optical system 530, target object 540, and target object 540. A wafer stage 545 to be placed, an alignment detection mechanism, and a focus position detection mechanism 560 are provided.

  Further, since EUV light has a low transmittance to the atmosphere and generates contamination due to a reaction with a residual gas (polymer organic gas or the like) component, as shown in FIG. 6, at least in an optical path through which the EUV light passes. (That is, the entire optical system) is in a vacuum atmosphere VC.

  The illumination device 510 is an illumination device that illuminates the reticle 520 with arc-shaped EUV light (for example, 13.4 nm) with respect to the arc-shaped field of the projection optical system 530. The illumination device 510 includes the EUV light source 512 and the illumination optical system 514. Have.

  As the EUV light source 512, for example, a laser plasma light source is used. In this method, a target material in a vacuum vessel is irradiated with high-intensity pulsed laser light to generate high-temperature plasma, and EUV light having a wavelength of, for example, about 13 nm is emitted from the target material. As the target material, a metal film, a gas jet, a droplet, or the like is used. In order to increase the average intensity of the emitted EUV light, the repetition frequency of the pulse laser should be high, and it is usually operated at a repetition frequency of several kHz.

  The illumination optical system 514 includes a condensing mirror 514a and an optical integrator 514b. The condensing mirror 514a collects EUV light emitted from the laser plasma isotropically. The optical integrator 514b has a role of uniformly illuminating the reticle 520 with a predetermined numerical aperture. In addition, the illumination optical system 514 is provided with an aperture 514c for limiting the illumination area of the reticle 520 to an arc shape at a position conjugate with the reticle 520.

  The reticle 520 is a reflective reticle, on which a circuit pattern (or image) to be transferred is formed, and is supported and driven by a reticle stage 525. The diffracted light emitted from the reticle 520 is reflected by the projection optical system 530 and projected onto the object to be processed 540. The reticle 520 and the object to be processed 540 are arranged in an optically conjugate relationship. Since the exposure apparatus 500 is a scanner, the pattern of the reticle 520 is reduced and projected onto the object 540 by scanning the reticle 520 and the object 540.

  The reticle stage 525 supports the reticle 520 and is connected to a moving mechanism (not shown). The reticle stage 525 holds the reticle 520 via a reticle chuck 525a. The holding device 100 of the present invention can be applied to the reticle chuck 525a. Thereby, deformation of the reticle 520, particularly deformation at the outer peripheral portion of the reticle 520, can be reduced, displacement can be prevented, and deterioration of transfer accuracy can be suppressed. A moving mechanism (not shown) is configured by a linear motor or the like, and can move the reticle 520 by driving the reticle stage 525 at least in the X direction. The exposure apparatus 500 scans the reticle 520 and the workpiece 540 in a synchronized state. Here, X is the scanning direction in the surface of the reticle 520 or the object to be processed 540, Y is the direction perpendicular to the scanning direction, and Z is the direction perpendicular to the surface of the reticle 520 or the object to be processed 540.

  The projection optical system 530 uses a plurality of reflecting mirrors (that is, multilayer mirrors) 530a to reduce and project the pattern on the reticle 520 onto the object 540 that is the image plane. The number of the plurality of reflection mirrors 530a is about 4 to 6. In order to realize a wide exposure area with a small number of mirrors, the reticle 520 and the object to be processed 540 are scanned simultaneously using only a thin arc-shaped area (ring field) separated from the optical axis by a certain distance. Transfer the area. The numerical aperture (NA) of the projection optical system 530 is about 0.2 to 0.3.

  The object to be processed 540 is a wafer in the present embodiment, but widely includes liquid crystal substrates and other objects to be processed. A photoresist is applied to the object to be processed 540. The photoresist coating process includes a pretreatment, an adhesion improver coating process, a photoresist coating process, and a prebaking process. Pretreatment includes washing, drying and the like. The adhesion improver coating process is a surface modification process for improving the adhesion between the photoresist and the base (that is, a hydrophobic process by application of a surfactant), and an organic film such as HMDS (Hexmethyl-disilazane) is used. Coat or steam. Pre-baking is a baking (baking) step, but is softer than that after development, and removes the solvent.

  Wafer stage 545 supports object 540 to be processed by wafer chuck 545a. For example, the wafer stage 545 moves the object 540 in the XYZ directions using a linear motor. The reticle 520 and the object to be processed 540 are scanned synchronously. Further, the position of reticle stage 525 and the position of wafer stage 545 are monitored by, for example, a laser interferometer or the like, and both are driven at a constant speed ratio. The holding device 100 of the present invention can be applied to the wafer chuck 545a. Accordingly, deformation of the object to be processed 540, particularly deformation at the outer peripheral portion of the object to be processed 540 can be reduced, and displacement can be prevented to prevent deterioration of transfer accuracy.

  The alignment detection mechanism 550 measures the positional relationship between the position of the reticle 520 and the optical axis of the projection optical system 530 and the positional relationship between the position of the workpiece 540 and the optical axis of the projection optical system 530, and The positions and angles of the reticle stage 525 and the wafer stage 545 are set so that the projected image coincides with a predetermined position of the workpiece 540.

  The focus position detection mechanism 560 measures the focus position in the Z direction on the surface of the object to be processed 540 and controls the position and angle of the wafer stage 545, so that the surface of the object to be processed 540 is always projected by the projection optical system 530 during exposure. Keep at the imaging position.

  In the exposure, the EUV light emitted from the illumination device 510 illuminates the reticle 520 and forms a pattern on the surface of the reticle 520 on the surface of the object to be processed 540. In this embodiment, the image surface is an arc-shaped (ring-shaped) image surface, and the entire surface of the reticle 520 is exposed by scanning the reticle 520 and the object to be processed 540 at a speed ratio of the reduction ratio.

  By applying the holding device 100 of the present invention to the reticle chuck 525a and wafer chuck 545a used by the exposure apparatus 500, deformation and misalignment of the reticle 520 and the object to be processed 540 can be suppressed. A high-quality device (semiconductor element, LCD element, imaging element (CCD, etc.), thin film magnetic head, etc.) can be provided.

  Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 500 will be described with reference to FIGS. FIG. 7 is a flowchart for explaining how to fabricate devices (ie, semiconductor chips such as IC and LSI, LCDs, CCDs, etc.). Here, the manufacture of a semiconductor chip will be described as an example. In step 1 (circuit design), a device circuit is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique of the present invention using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer created in step 4. The assembly process (dicing, bonding), packaging process (chip encapsulation), and the like are performed. Including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

  FIG. 8 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition or the like. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 500 of the present invention to expose a circuit pattern on the mask onto the wafer. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeatedly performing these steps, multiple circuit patterns are formed on the wafer. According to the device manufacturing method of the present invention, it is possible to manufacture a higher quality device than before. As described above, the device manufacturing method using the lithography technique of the present invention and the resulting device also constitute one aspect of the present invention.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist. For example, the holding device of the present invention can be applied to ultraviolet light having a wavelength of 200 nm or less other than EUV light, such as ArF excimer laser and F ₂ laser, and can hold optical members constituting a projection optical system, illumination optical system, and the like. Is also applicable.

It is a schematic sectional drawing which shows the structure of the holding | maintenance apparatus of this invention. It is a schematic plan view which shows an example of arrangement | positioning of the suction pin of the chuck | zipper surface shown in FIG. It is a schematic plan view which shows another example of arrangement | positioning of the suction pin of the chuck | zipper surface shown in FIG. It is a schematic plan view which shows the surface of the chuck | zipper of the holding | maintenance apparatus of this invention. It is a schematic plan view which shows the surface of the chuck | zipper of the holding | maintenance apparatus of this invention. 1 is a schematic optical path diagram showing an exemplary exposure apparatus of the present invention. It is a flowchart for demonstrating manufacture of devices (semiconductor chips, such as IC and LSI, LCD, CCD, etc.). 8 is a detailed flowchart of the wafer process in Step 4 shown in FIG. 7. It is the schematic sectional drawing and the expanded sectional view which show the board | substrate with which the position shift of the surface produced due to the change of the amount of local curvature. It is a schematic sectional drawing which shows the board | substrate which has surface roughness on the back surface, and the board | substrate which the local curvature generate | occur | produced due to this surface roughness. It is a schematic sectional drawing of the board | substrate which produced the curvature in the outer peripheral part with respect to the center part. It is the schematic plan view and sectional drawing which show the case where the board | substrate which produced the curvature in the outer peripheral part was adsorbed with a pin chuck.

Explanation of symbols

100 holding device 110 chuck 120 suction pin 122 suction surface 140 electrode 100A holding device 160 suction pin 162 suction surface 100B holding device 170 suction pin 172 suction surface PS predetermined substrate BP reference surface PC1 first suction pin group PC2 second suction Pin group 500 Exposure apparatus 525 Reticle stage 525a Reticle chuck 545 Wafer stage 545a Wafer chuck

Claims (14)

A holding device for holding a predetermined substrate,
A plurality of protrusions for adsorbing the predetermined substrate through an adsorption surface that defines a reference surface for aligning the predetermined substrate;
The plurality of convex portions have the same suction force, and are arranged so that the suction density is larger in the radial direction than in the circumferential direction of the reference surface. A holding device for holding a predetermined substrate,
A plurality of protrusions for adsorbing the predetermined substrate through an adsorption surface having a diameter of 0.1 mm or more that defines a reference surface for aligning the predetermined substrate;
The plurality of convex portions, the total area of the suction surface with respect to the area of the predetermined substrate is 10% or less,
The holding device according to claim 1, wherein an adsorption density of the plurality of convex portions is larger in a radial direction than a circumferential direction of the reference surface.   3. The holding device according to claim 1, wherein the suction density in the radial direction of the reference surface is 1.5 to 5 times the suction density in the circumferential direction of the reference surface.   The plurality of convex portions are concentric circles in which the distance between the arbitrary convex portion and the convex portion having the shortest perpendicular line extending from the line connecting the arbitrary convex portion and the center of the reference plane passes through the arbitrary convex portion. The holding device according to claim 1, further comprising a convex portion group disposed so that a perpendicular line with respect to the tangent line is smaller than a distance from the shortest convex portion.   The holding device according to claim 4, wherein the convex portion group is disposed on an outer peripheral portion of the reference surface.   The holding device according to claim 1, wherein the suction surface has a shape in which a length in a radial direction of the reference surface is longer than a length in a circumferential direction of the reference surface. The plurality of convex portions are a first convex portion group arranged in a ring shape continuous in the circumferential direction of the reference surface;
A second convex portion group arranged in a distributed manner inside the first convex portion group,
In the outermost convex portion on the first convex portion group side in the second convex portion group, the distance from the first convex portion group is reduced to a tangent line of a concentric circle passing through the outermost convex portion. The holding device according to claim 1, wherein the vertical line is arranged to be smaller than a distance from the shortest convex portion. A holding device for holding a predetermined substrate,
A plurality of ring-shaped convex portions that adsorb the predetermined substrate through an adsorption surface that defines a reference surface that aligns the predetermined substrate;
The holding device according to claim 1, wherein the plurality of ring-shaped convex portions are spaced apart from each other in the radial direction of the reference surface as the distance from the center of the reference surface increases.   The holding apparatus according to claim 1, wherein the predetermined substrate is a wafer onto which a desired pattern is transferred.   The holding apparatus according to claim 1, wherein the predetermined substrate is a reticle on which a desired pattern to be transferred to a wafer is formed.   A light beam emitted from a light source is irradiated onto a target object held by a holding device according to any one of claims 1 to 8 through a projection optical system to expose the target object. Exposure equipment.   The light beam emitted from the light source is used to illuminate the reticle on which the desired pattern held by the holding device according to any one of claims 1 to 8 is formed, and the target pattern is exposed to the object to be processed. An exposure apparatus characterized by:   An exposure apparatus comprising the holding device according to claim 1. A step of exposing the object to be processed using the exposure apparatus according to claim 11;
And performing a predetermined process on the exposed object to be processed.

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