JP7581146B2 - Chuck, substrate holding device, substrate processing device, and method for manufacturing article - Google Patents

Description

The present invention relates to a chuck, a substrate holding device, a substrate processing device, and a method for manufacturing an article.

In recent years, exposure devices (reduction projection exposure devices) used in semiconductor device manufacturing, etc., have been increasing in NA to accommodate the miniaturization of devices. Increasing the NA improves resolution, but reduces the effective depth of focus. Therefore, in order to maintain resolution and ensure sufficient practical depth, efforts have been made to improve wafer flatness (flatness of the substrate surface) by reducing the field curvature of the projection optical system, improving unevenness in the thickness of the wafer (substrate), and improving the flatness accuracy of the chuck that adsorbs and holds the wafer.

One of the causes of the reduction in the flatness of the substrate surface is the inclusion of foreign matter between the chuck and the substrate. When a foreign matter is trapped, the substrate in the trapped area is deformed and rises, which can cause defects in the formation of the pattern on the substrate and reduce yield. In order to probabilistically avoid such a reduction in yield due to foreign matter, a pin contact chuck (pin chuck) is used, which uses so-called pins (protruding parts) that greatly reduce the contact rate between the chuck and the substrate.

When this pin chuck is used, the vacuum suction force between the protrusions can cause the substrate to deform and bend (warp), resulting in a decrease in the flatness of the substrate surface, and various proposals have been made to improve this. For example, in Patent Document 1, a ring-shaped partition (bank) that surrounds multiple protrusions is provided on the pin chuck, and this partition is disposed between the outer circumferential protrusion and the inner circumferential protrusion that is adjacent to the outer circumferential protrusion. The partition is disposed as close as possible to the outer circumferential protrusion.

In addition, in Patent Document 2, the partition wall is disposed at a position outside the outermost convex portion, or between the outermost convex portion and the convex portion on the inner periphery adjacent to the outermost convex portion. The partition wall is disposed at a position within a predetermined range in the outer periphery direction from the center of the distance between the outermost convex portion and the convex portion on the inner periphery adjacent to the outermost convex portion.

Patent No. 4298078 JP 2001-185607 A

When the substrate is vacuum-adsorbed, the inside of the partition is kept at a vacuum pressure and an adsorption force is generated, but the outside of the partition is at atmospheric pressure and almost no adsorption force is generated. In Patent Documents 1 and 2, the partition is positioned close to the outer peripheral convex portion in order to allow the adsorption force to act as far as possible on the outside of the substrate. However, because the adsorption force acts on the outside of the substrate, the flatness of the substrate surface decreases, resulting in a problem of increased distortion of the substrate.

The present invention therefore aims to provide a chuck that can reduce distortion of the substrate, for example by arranging the partition and the protrusion in a predetermined relationship.

To achieve the above object, a chuck according to one aspect of the present invention includes a plurality of protrusions that contact the back surface of a substrate held by suction, an annular partition wall, and a bottom on which the plurality of protrusions and the partition wall are arranged, the plurality of protrusions being composed of a plurality of groups, each group being a first protrusion arranged on the outside of the partition wall and a second protrusion arranged on the inside of the partition wall adjacent to the first protrusion with the partition wall in between, and is characterized in that, where L is the distance between the first protrusion and the second protrusion in each of the plurality of groups, and s is the distance between the second protrusion and the partition wall, s/L<0.5 is satisfied.

The present invention provides a chuck that can reduce distortion of a substrate, for example, by arranging the partition and the protrusion in a predetermined relationship.

1 is a schematic diagram illustrating the configuration of an exposure apparatus according to a first embodiment. FIG. 13 is a diagram illustrating a material mechanics model of a beam with one side fixed and one side free that is subjected to a uniformly distributed load. 1 is a diagram illustrating a substrate holding device according to a first embodiment; FIG. 2 is a diagram illustrating a material mechanics model of the first embodiment. 1 is a diagram illustrating the relationship between the partition position and distortion in Example 1. FIG. FIG. 11 is a diagram illustrating a substrate holding device according to a second embodiment. 13 is a diagram illustrating a substrate holding device according to a third embodiment. FIG. 13 is a diagram illustrating a material mechanics model for a cantilever beam. FIG. 13 is a cross-sectional view of a chuck according to a third embodiment. 13 is a diagram illustrating a substrate holding device according to a fifth embodiment. 1 is a flow chart illustrating a manufacturing process for a device. 1 is a flow chart illustrating a wafer process. 1 is a diagram illustrating a pin chuck used in a typical substrate holding device.

Below, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In each drawing, the same reference numbers are used for the same members or elements, and duplicate descriptions will be omitted or simplified.

Example 1
1 is a diagram illustrating a schematic configuration of an exposure apparatus 100 according to the present embodiment. The exposure apparatus 100 is an apparatus that can irradiate light (exposure light) emitted from a light source onto a resist to harden it, thereby forming a hardened pattern into which a pattern formed on a reticle 104 is transferred.

In the following description, the direction parallel to the optical axis of the light irradiated onto the resist on the substrate 110 is defined as the Z-axis direction, and the two directions perpendicular to each other in a plane perpendicular to the Z-axis direction are defined as the X-axis direction and the Y-axis direction. The exposure apparatus 100 of this embodiment is applicable to an apparatus that performs sequential focus driving on multiple pattern formation regions (exposure regions) and an apparatus that performs sequential exposure (projection exposure apparatus, substrate processing apparatus), etc. The exposure apparatus 100 of this embodiment will be described below with reference to FIG. 1. Note that the exposure apparatus 100 of this embodiment will be described as a step-and-repeat type exposure apparatus.

The substrate (wafer) 110 is a substrate to be processed, the surface of which is coated with a photosensitive agent (resist) that effectively causes a chemical reaction when exposed to light. The substrate 110 may be made of glass, ceramics, metal, silicon, resin, etc., and if necessary, a member made of a material other than the substrate 110 may be formed on the surface. The substrate 110 may also be a variety of substrates, such as a gallium arsenide wafer, a composite adhesive wafer, a glass wafer containing quartz, a liquid crystal panel substrate, or a reticle. The outer shape may also be not only circular but also rectangular, and in that case, the outer shape of the chuck 1, which will be described later, may be shaped to match the outer shape of the substrate.

The reticle (original) 104 is placed on a reticle stage 103 that is configured to be movable in a plane perpendicular to the optical axis of the projection optical system 106 and in the direction of this optical axis. The reticle 104 has a rectangular outer periphery and has a pattern portion with a three-dimensional pattern (a concave-convex pattern to be transferred to the substrate, such as a circuit pattern) on the surface (pattern surface) facing the substrate 110. The reticle 104 is made of a material that can transmit light, such as quartz.

The exposure apparatus 100 of this embodiment also functions as a substrate processing apparatus, and may include a substrate holding device 101, a substrate stage 102, a reticle stage 103, an illumination optical system 105, a projection optical system 106, an off-axis scope 107, a measurement unit 108, and a control unit 109.

The substrate holding device 101 may include a chuck 1 for suction-holding the substrate 110, a suction unit (not shown) that is a vacuum source for sucking (exhausting) the space between the back surface of the substrate 110 and the chuck 1, and a control unit (not shown) that controls the suction unit. Details of the substrate holding device 101 in this embodiment will be described later.

The substrate stage 102 comprises a θZ tilt stage that holds the substrate 110 via the substrate holding device 101, an XY stage (not shown) that supports the θZ tilt stage, and a base (not shown) that supports the XY stage. The substrate stage 102 is driven by a driving device (not shown) such as a linear motor. The driving device can be driven in six axial directions, namely X, Y, Z, θX, θY, and θZ, and is controlled by a control unit 109, which will be described later. Note that although the driving device is capable of driving in six axial directions, it may be capable of driving in any one of one to six axial directions.

The reticle stage 103 is configured to be movable within a plane perpendicular to the optical axis of the projection optical system 106 described below, i.e., within the XY plane, and to be rotatable in the θZ direction. The reticle stage 103 is driven by a driving device (not shown) such as a linear motor, which is capable of driving in three axial directions, X, Y, and θZ, and is controlled by a control unit 109 described below. Note that although the driving device is capable of driving in three axial directions, it may also be capable of driving in any one of one to six axial directions.

The illumination optical system 105 includes a light source (not shown) and illuminates the reticle 104 on which a circuit pattern (reticle pattern) for transfer is formed. For example, a laser is used as the light source included in the light source. Usable lasers include an ArF excimer laser with a wavelength of about 193 nm, a KrF excimer laser with a wavelength of about 248 nm, and an F2 excimer laser with a wavelength of about 157 nm. The type of laser is not limited to an excimer laser, and for example, a YAG laser may be used, and the number of lasers is not limited. In addition, when a laser is used in the light source section, it is preferable to use a light beam shaping optical system that shapes a parallel light beam from a laser light source into a desired beam shape, and an incoherent optical system that makes a coherent laser incoherent. Furthermore, the light source that can be used is not limited to a laser, and one or more lamps such as a mercury lamp or a xenon lamp can also be used.

The illumination optical system 105 also includes lenses, mirrors, a light integrator, and an aperture, which are not shown. In general, the internal optical system is arranged in the following order: a condenser lens, a fly's eye, an aperture stop, a condenser lens, a slit, and an imaging optical system. In this case, the light integrator includes a fly's eye lens and an integrator formed by stacking two sets of cylindrical lens array plates.

The projection optical system 106 forms an image of the diffracted light of the pattern on the reticle 104 illuminated by the exposure light from the illumination optical system 105 on the substrate 110 at a predetermined magnification (e.g., 1/2, 1/4, or 1/5). The interference image formed on the substrate 110 forms an image that is almost the same as the reticle pattern. This interference image is generally called an optical image, and the shape of the optical image determines the line width formed on the substrate 110. The projection optical system 106 can be an optical system consisting of only multiple optical elements, or an optical system consisting of multiple optical elements and at least one concave mirror (catadioptric optical system). Alternatively, the projection optical system 106 can be an optical system consisting of multiple optical elements and at least one diffractive optical element such as a kinoform, or an all-mirror type optical system.

The off-axis scope 107 is used to position the substrate 110 and detect the positions of multiple pattern formation regions on the substrate 110. It can detect and measure the relative position between a reference mark placed on the substrate stage 102 and a mark formed on the substrate 110 mounted on the substrate stage 102. The measurement unit (surface position measurement means) 108 is a measurement device that can adjust the focus of the projection optical system 106 to the exposure target region of the substrate 110, and constitutes a focusing device that adjusts the focus of the projection optical system 106 to the substrate surface.

The control unit 109 is composed of at least one computer including a CPU and memory (storage unit), and is connected to each component of the exposure apparatus 100 via a line. The control unit 109 also performs overall control of the operation and adjustment of each component of the entire exposure apparatus 100 according to a program stored in the memory. The control unit 109 may be configured integrally with the other parts of the exposure apparatus 100 (in a common housing), or may be configured separately from the other parts of the exposure apparatus 100 (in a different housing), or may be installed in a location separate from the exposure apparatus 100 and controlled remotely.

The exposure sequence of the exposure apparatus 100 will now be described. Each operation (process) shown in the exposure sequence is controlled by the control unit 109 executing a computer program. When the exposure sequence is started, the substrate 110 is set in the exposure apparatus 100 automatically or manually by the operator, and then the operation of the exposure apparatus 100 is started in response to an exposure start command.

First, the first substrate 110 to be exposed is loaded into the substrate carrier in the exposure apparatus 100 by a transport mechanism (not shown) (loading process). Next, the substrate 110 is sent by the transport mechanism onto the chuck 1 mounted on the substrate stage 102, and is adsorbed and held by the substrate holding device 101 (substrate holding process).

Next, multiple marks formed on the substrate 110 are detected by the off-axis scope 107 mounted on the exposure apparatus 100 to determine the magnification, rotation, and misalignment in the X-axis and Y-axis directions of the substrate 110, and position correction is performed (alignment process).

Next, the substrate stage 102 moves the substrate 110 so that the predetermined pattern formation area of the substrate 110 that is to be exposed first is aligned with the exposure position of the exposure device 100. Next, after focusing by the measurement unit 108, light is irradiated from the light source, and the resist applied within the predetermined pattern formation area is exposed for a predetermined time (exposure process). The exposure time is, for example, about 0.2 seconds.

Next, the substrate stage 102 moves (steps) the substrate 110 to the next pattern formation area on the substrate 110 and exposes it in the same manner as above. The same pattern formation process is repeated in sequence until exposure is completed in all pattern formation areas to be exposed. This allows the pattern formed on the reticle 104 to be formed on one substrate 110. The substrate 110 is then transferred from the chuck 1 to a recovery transport hand (not shown) and returned to the substrate carrier in the exposure device 100 (unloading process). After the unloading process of the substrate 110, the substrate 110 is processed by, for example, etching or other processes (processing process), and an article can be manufactured by removing unnecessary cured material from the processed substrate 110.

As described above, this embodiment assumes a step-and-repeat type exposure apparatus, but is not limited to this and can also be applied to a scanning type exposure apparatus. When applied to a scanning type exposure apparatus, the reticle and substrate 110 are scanned synchronously based on the exposure magnification, and exposure is performed during the scan.

The substrate holding device 101 of this embodiment is not limited to use in the exposure device 100. For example, it can also be used in substrate processing devices including imprint devices (lithography devices), liquid crystal substrate manufacturing devices, magnetic head manufacturing devices, semiconductor inspection devices, liquid crystal substrate inspection devices, magnetic head inspection devices, and in the manufacture of micromachines.

Here, when the substrate 110 is attracted and held by the chuck 1, a foreign object may be trapped between the substrate 110 and the chuck 1. For example, even if the foreign object is only a few μm in size, if the foreign object is trapped, the substrate 110 at the trapped portion may deform and partly rise, resulting in defective pattern formation. As an example, this may occur when the effective depth of focus is 1 μm or less.

To prevent such pinching by foreign objects, a so-called pin contact chuck (hereinafter, chuck) is used, in which the portion that contacts the back surface of the substrate 110 is formed as a pin-shaped protrusion, thereby greatly reducing the contact area with the substrate 110. Below, a chuck used in a conventional general substrate holding device is described with reference to FIG. 13.

Figure 13 illustrates an example of a chuck 200 used in a typical substrate holding device. Figure 13(A) is a plan view of the chuck 200 as viewed from the +Z direction. Figure 13(B) is a partial cross-sectional view of the chuck 200 shown in Figure 13(A). The substrate holding device illustrated in Figure 13 can be composed of a chuck 200, a protrusion 201, a partition (first partition) 204, and a suction port 205.

The protrusions 201 function as a contact surface (a support surface that supports the substrate after it is placed) that contacts the rear surface of the substrate 110. The multiple pin-shaped protrusions 201 can include multiple pin-shaped protrusions (outer peripheral protrusions) 202, multiple pin-shaped protrusions (inner peripheral protrusions) 203, and multiple pin-shaped protrusions different from the outer peripheral protrusions 202 and the inner peripheral protrusions 203.

The partition wall 204 is provided in an annular shape on the bottom of the chuck 200 so as to be inside the outer peripheral convex portion 202. The height of the partition wall 204 is formed to be about 1 to 2 μm lower than the upper surface of the outer peripheral convex portion 202. The suction port 205 is a through hole formed in the bottom of the chuck 200, and is connected to a flow path formed by a pipe or the like that communicates with a vacuum source (suction portion) not shown.

The outer circumferential side protrusion 202 is arranged outside the partition wall 204 so as to abut against the back surface of the substrate 110 in the outer circumferential direction. The outer circumferential side protrusion 202 is arranged on the outer periphery with the same radius as the substrate 110. The outer circumferential side protrusion 202 illustrated in FIG. 13 is a protrusion arranged on the outermost side (outermost circumference) of the chuck 200. The inner circumferential side protrusion 203 is arranged inside the partition wall 204 so as to abut against the back surface of the substrate 110 in the inner circumferential direction. The inner circumferential side protrusion 203 illustrated in FIG. 13 is arranged next to the outer circumferential side protrusion 202 arranged at the bottom on the outermost side, with the partition wall 204 in between. In addition, the multiple pin-shaped protrusions 201 in the chuck 200 can be arranged in a lattice pattern at a predetermined distance (spacing, period, width). In addition, the outer circumferential side convex portion 202 arranged on the outside of the partition wall 204, and the inner circumferential side convex portion 203 arranged on the inside of the partition wall 204 and adjacent to the outer circumferential side convex portion 202 with the partition wall 204 in between, are each configured as one group. Then, the multiple convex portions formed by the outer circumferential side convex portion 202 and the inner circumferential side convex portion 203 are configured as multiple groups including each group.

The method of adsorbing the substrate 110 with the chuck 200 configured as described above will be described below. First, the substrate 110 is placed on the convex portions 201 of the chuck 200. This causes the back surface of the substrate 110 to abut on the multiple convex portions 201. Next, the substrate 110 is vacuum-sucked through the suction port 205 by operating a vacuum source (not shown), so that the substrate 110 is supported and adsorbed by the convex portions 201 of the chuck 200. At this time, the substrate 110 is deformed and warped by the vacuum suction force between the convex portions 201. The warping of the substrate 110 reduces the flatness of the substrate 110, causing so-called wafer distortion (hereinafter, distortion).

The flatness and distortion of the substrate 110 at the outer circumferential convex portion 202 will be described below from a material mechanics model with reference to FIG. 2, taking the arrangement position of the partition wall 204 illustrated in FIG. 13(B) as an example. FIG. 2 illustrates a material mechanics model of a beam that is fixed on one side and free on the other side and receives a uniformly distributed load. The material mechanics model of the deflection state of the substrate 110 in the outer circumferential region (outer periphery) of the chuck 200 corresponds to the model illustrated in FIG. 2. As illustrated in FIG. 13(B), the partition wall 204 is arranged closer to the outer circumferential convex portion 202 than the inner circumferential convex portion 203.

Let E be the Young's modulus of the substrate 110, and h be the thickness of the substrate 110. Next, let L be the distance between the outer circumferential side convex portion 202 and the inner circumferential side convex portion 203 included in each of the aforementioned multiple groups (hereinafter, multiple groups). Furthermore, let w be the acting force per unit length, y be the deflection, and x be the radial position of the inner circumferential side convex portion 203 as a reference. In this case, the inclination (θ)dy/dx is expressed by the following formula (1). Note that the distance L may be the average value of the distances between the outer circumferential side convex portion 202 and the inner circumferential side convex portion 203 included in each of the multiple groups.

上記式（１）における傾斜ｄｙ／ｄｘは、ｘ＝Ｌで最大となり以下の式（２）で表される。

The slope dy/dx in the above formula (1) is maximum when x=L and is expressed by the following formula (2).

ここで、上記式（２）における、マイナス表記は傾斜ｄｙ／ｄｘが反時計回り（ＣＣＷ）の回転方向であることを示している。また、真空源による吸引圧を吸引圧力Ｐｖとして、奥行寸法をｂとすると、単位長さあたりの作用力ｗは、以下の式（３）で表される。

Here, in the above formula (2), the minus sign indicates that the slope dy/dx is in the counterclockwise (CCW) direction. In addition, if the suction pressure by the vacuum source is the suction pressure Pv and the depth dimension is b, the acting force w per unit length is expressed by the following formula (3).

ここで、片側自由の梁における断面二次モーメントＥ＝１／１２ｂｈ^３として、上記式（３）を上記式（２）に代入すると、以下の式（４）が得られる。

Here, assuming that the second moment of area E of a beam with one side free is 1/ ^12bh3 , by substituting the above formula (3) into the above formula (2), the following formula (4) is obtained.

そして、ディストーションｄｘは以下の式（５）で表される。

The distortion dx is expressed by the following equation (5).

なお、厳密には、外周側凸部２０２は、吸引等により基板１１０に荷重が掛かった際に基板１１０の変形により、当該外周側凸部２０２の中心部（外周側凸部の中心軸上における支持面）ではなく、中心部からずれた角部で基板１１０を支持することになる。そのため、この場合の上記距離Ｌ（ｍｍ）は、厳密には当該外周側凸部２０２の基板１１０の中心方向に対して外周側凸部２０２の角部から隔壁２０４を挟んで当該外周側凸部の隣に配置される内周側凸部２０３の中心軸までの距離となる。上記ディストーションを算出する上では、距離Ｌにおける距離が長い方がディストーションは大きくなるため、安全側で計算すべくディストーションの算出には上記の距離Ｌを採用している。

Strictly speaking, when a load is applied to the substrate 110 by suction or the like, the outer peripheral convex portion 202 supports the substrate 110 not at the center (the support surface on the central axis of the outer peripheral convex portion) of the outer peripheral convex portion 202 but at a corner portion offset from the center due to deformation of the substrate 110. Therefore, the distance L (mm) in this case is strictly the distance from the corner of the outer peripheral convex portion 202 to the central axis of the inner peripheral convex portion 203 disposed next to the outer peripheral convex portion across the partition wall 204 in the direction of the center of the substrate 110. In calculating the distortion, the longer the distance L is, the larger the distortion is, so the distance L is adopted for calculating the distortion to be on the safe side.

As an example, when the design values of a typical chuck, E = 160 GPa, Pv = 0.1 MPa, L = 2 mm, and h = 0.7 mm, are substituted into the above formula (5), dx = 1.29 nm is obtained. For example, if the tolerance of the overlay error with respect to the ideal horizontal reference is 1.5 nm, the tolerance remains at only 0.29 nm. Furthermore, even if the tolerance of the overlay error with respect to the ideal horizontal reference is, for example, 3 nm or 5 nm, a distortion of 1.29 nm has a large effect on the process of forming a pattern on the substrate 110. Therefore, in order to perform a process such as pattern formation after the substrate 110 is held by suction, the substrate 110 needs to be held by suction in a state where the distortion is reduced.

In this embodiment, therefore, a chuck capable of reducing distortion can be provided by positioning the partition wall 5 in a predetermined relationship with the protrusion 2 described below. The substrate holding device 101 of this embodiment will be described in detail below with reference to Figures 3 to 5.

Figure 3 is a diagram illustrating the substrate holding device 101 of this embodiment. Figure 3(A) is a plan view of the substrate holding device 101 as viewed from the +Z direction. Figure 3(B) is a partial cross-sectional view of the substrate holding device 101 of Figure 3(A). Below, the substrate holding device 101 of this embodiment will be described in detail with reference to Figure 3. The substrate holding device 101 of this embodiment can include a chuck 1, a suction unit (not shown), and a control unit.

The chuck 1 is circular and has a smaller diameter than the substrate 110, and may include a plurality of pin-shaped protrusions 2, a partition (first partition) 5, and a suction port (first suction port) 6. The chuck 1 is placed on the substrate stage 102.

The protrusions 2 are pin-shaped protrusions (pins) arranged in multiple numbers on the bottom of the chuck 1, and when the substrate 110 is placed on the chuck 1, the back surface of the substrate 110 abuts against the upper surface of the protrusions 2. The protrusions 2 are arranged in a lattice pattern at a predetermined distance L (mm) on the bottom of the chuck 1. The diameter of the protrusions 2 varies depending on the specifications of the chuck 1, but a typical diameter is about φ0.2 mm. In addition to the lattice pattern, the protrusions 2 can also be arranged concentrically or at an angle, for example, in a lattice pattern with a 60-degree staggered pattern. They can also be arranged randomly, or a combination of these.

The convex portion 2 may include a plurality of pin-shaped convex portions (outer peripheral convex portion, first convex portion) 3, a plurality of pin-shaped convex portions (inner peripheral convex portion, second convex portion) 4, and a plurality of pin-shaped convex portions (third convex portion) different from the outer peripheral convex portion 3 and the inner peripheral convex portion 4. The outer peripheral convex portion 3 is arranged outside the partition wall 5 so as to abut against the back surface in the outer peripheral direction of the substrate 110. The outer peripheral convex portion 3 is a convex portion arranged in multiple on the outer circumference with the same radius as the substrate 110. The outer peripheral convex portion 3 illustrated in FIG. 3 is arranged on the outermost side (outermost circumference) of the chuck 1. The inner peripheral convex portion 4 is arranged inside the partition wall 5 so as to abut against the back surface in the inner peripheral direction of the substrate 110. The inner peripheral convex portion 4 is arranged in multiple on the inner circumference with the same radius as the substrate 110. The inner peripheral convex portion 4 illustrated in FIG. 3 is arranged adjacent to the outer peripheral convex portion 3 arranged at the bottom on the outermost side, sandwiching the partition wall 5. In this embodiment, the multiple protrusions 2, excluding the third protrusion, are configured into multiple groups, each group consisting of an outer circumferential side protrusion 3 arranged on the outside of the partition wall 5, and an inner circumferential side protrusion 4 arranged on the inside of the partition wall 5, adjacent to the outer circumferential side protrusion 3 with the partition wall 5 in between.

At least one partition wall 5 is arranged on the bottom of the chuck 1 in an annular shape so as to surround a part of the multiple protrusions 2. In this embodiment, the partition wall 5 is arranged in a position close to the inner circumferential side protrusion 4 adjacent to the outer circumferential side protrusion 3 across the partition wall 5. The partition wall 5 is formed lower than the multiple inner circumferential side protrusions 4. The height of the multiple inner circumferential side protrusions 4 is, for example, the average height. The height of the partition wall 5 may also be lower than the height of a specific inner circumferential side protrusion 4, for example, the inner circumferential side protrusion 4 with the lowest height among the multiple inner circumferential side protrusions 4. The height of the partition wall 5 may also be formed about 1 to 2 μm lower than the upper surface of the multiple protrusions 2. Even if the partition wall 5 is formed about 1 to 2 μm lower, with a gap of about 1 to 2 μm, the decrease in vacuum pressure when the suction part described later sucks the space (area) between the back surface of the substrate 110 and the chuck 1 to suction and hold the substrate 110 is slight and does not cause a problem. Furthermore, even if foreign matter such as dust or particles with a diameter smaller than the difference of about 1 to 2 μm adheres to the partition 5, the probability that the adhered foreign matter will come into contact with the back surface of the substrate 110 is very low, so there is no problem even if the height of the partition 5 is formed to be about 1 to 2 μm lower than the upper surfaces of the multiple protrusions 2.

The suction port 6 is a through hole formed in the chuck 1, and in this embodiment, it functions as a suction port when the suction unit described later sucks (exhausts) the space between the back surface of the substrate 110 and the chuck 1. Note that while only one suction port 6 is provided in FIG. 3, this is not limiting and one or more suction ports 6 may be formed in the chuck 1.

The suction unit is a vacuum source (not shown) configured to be able to suck the space between the back surface of the substrate 110 and the chuck 1 by vacuum suction or the like. The suction unit starts operating in response to a signal from the control unit 109, and can suck the space between the back surface of the substrate 110 and the chuck 1 through a flow path such as a pipe connected to the suction unit and the suction port 6, thereby adsorbing the substrate 110 to the chuck 1. Note that the suction unit is not limited to being disposed in the substrate holding device 101, and may be disposed outside the substrate holding device 101 or outside the exposure device 100.

Figure 4 is a diagram illustrating a material mechanics model at the placement position of the partition wall 5 in this embodiment. Figure 4(A) is a partial cross-sectional view of the substrate holding device 101 in this embodiment. Figure 4(B) is a diagram illustrating a material mechanics model in the partial cross-sectional view of Figure 4(A).

In FIG. 4B, the inclination dy/dx is 0 (zero) at the inner circumferential side convex portion 4, so this is approximated by a fixed end. Also, in FIG. 4B, the force of the vacuum pressure P acts as a uniformly distributed load between the inner circumferential side convex portion 4 and the partition wall 5, and the force does not act on the outer circumferential side convex portion 3 adjacent to the inner circumferential side convex portion 4 across the partition wall 5. Therefore, the inclination dy/dx is free at the outer circumferential side convex portion 3, so this is approximated by a free end. This is a so-called statically indeterminate beam, as in FIG. 2, and by providing the condition of displacement = 0 at the outer circumferential side convex portion 3 in addition to the balance of forces and moments, the fixed end reaction force Rf, the free end reaction force Rp, and the moment Mf at the fixed end can be calculated. Below, the calculation of distortion in the substrate holding device 101 of this embodiment using the material mechanics model in FIG. 4B will be described.

Let the deflection be y, and let the distance from the inner circumferential projection 4 that is located closest in linear distance to the outer circumferential projection 3 among the inner circumferential projections 4 adjacent to the outer circumferential projection 3 included in each of the multiple groups across the partition 5 be distance s, to the partition 5. Next, let the distance between the outer circumferential projection 3 and the inner circumferential projection 4 included in each of the multiple groups be distance L. Note that distance L may be the average value of the distances between the outer circumferential projection 3 and the inner circumferential projection 4 included in each of the multiple groups. In this case, the equation for deflection can be expressed by the following formula (6) using the above-mentioned Rf, Rp, and Mf, assuming 0<x≦s.

そして、ｓ＜ｘ≦Ｌとした場合では、以下の式（７）で表すことができる。

In addition, when s<x≦L, it can be expressed by the following equation (7).

Next, by integrating the above equation (7) and inserting the condition dy/dx = 0 at the fixed end, we obtain the following equation (8).

次に、上記式（７）を積分して、隔壁５の配置位置での傾斜ｄｙ／ｄｘが連続という条件を入れることで、以下の式（９）が得られる。

Next, by integrating the above formula (7) and inserting the condition that the gradient dy/dx at the arrangement position of the partition 5 is continuous, the following formula (9) is obtained.

Furthermore, when Rf and Mf are calculated from the aforementioned displacement balance, force balance, and moment balance, the following equations (10) and (11) are obtained with u = s/L as a parameter.

Then, when x=L and the above formula (3) and the second moment of area E=1/ ^12bh3 are substituted into the above formula (9), the following formula (12) is obtained.

ここで、上記式（１２）における傾斜ｄｙ／ｄｘは時計回り（ＣＷ）を＋（プラス）表記としている。なお、予め反時計回り（ＣＣＷ）を＋と定義しているなら－１を掛ければ同様となる。また、傾斜ｄｙ／ｄｘに厚さｈ／２を掛けるとディストーションｄｘが以下の式（１３）によって得られる。

Here, in the above formula (12), the tilt dy/dx is expressed as + (plus) in the clockwise (CW) direction. If the counterclockwise (CCW) direction is previously defined as +, multiplying by -1 will result in the same result. Furthermore, multiplying the tilt dy/dx by the thickness h/2 gives the distortion dx according to the following formula (13).

Next, u is determined based on the distortion dx obtained by the above formula (13) so as to satisfy the following formula (14).

上記式（１４）における補正係数とは実質的な距離Ｌを考慮した係数であって、凸部２の配置位置により異なるが、１に近い数字である。

The correction coefficient in the above formula (14) is a coefficient taking into consideration the substantial distance L, and is a number close to 1, although it differs depending on the arrangement position of the convex portion 2.

Furthermore, when the flatness specification is dz and the length of the portion that protrudes in the peripheral direction (outward direction) beyond the outer peripheral side convex portion 3 located on the outermost side of the substrate 110 is oh, that is, the so-called overhanging length, u may be determined so as to satisfy the following formula (15).

Fig. 5 is a diagram illustrating the relationship of distortion to the arrangement position of the partition 5 in this embodiment. The vertical axis of the graph in Fig. 5 is a value calculated by substituting, for example, E = 160 ^{GPa ,} Pv ⁼ 0.1 MPa, L = 2 mm, and h ⁼ 0.7 mm, which are design values of a typical chuck 1, into the correction coefficient × (h/2) × PvL / 4Eh (3u - 4u). The horizontal axis also shows u as a variable.

According to FIG. 5, if u<0.5, the maximum distortion dx can be 0.4 nm, which can significantly reduce the impact on processes such as holding the substrate 110 by suction and forming a pattern on the substrate 110.

In reality, multiple protrusions 2 are arranged two-dimensionally, and the actual distance L between protrusions 2, including the reduction due to hitting the corners of the protrusions, is substantially smaller (shorter) than the distance L defined above. Therefore, if the distance L used in the above distortion calculation is larger (longer) than the actual arrangement, the distortion will be large. In this embodiment, the above distance L is used to calculate the distortion in order to be on the safe side.

As described above, in this embodiment, distortion can be reduced by adjusting the position of the partition 5 (setting the position of the partition 5 in a predetermined relationship with respect to the protrusion 2) so as to satisfy u<0.5. This makes it possible to provide a chuck that can adsorb and hold the substrate 110 in an optimal state when performing processes such as pattern formation.

Example 2
The substrate holding device 101 of this embodiment is a substrate holding device further provided with an auxiliary partition (second partition) 7 as a partition different from the partition (first partition) 5 in the chuck 1 of the first embodiment, and a suction port (second suction port) 8 which is a suction port different from the suction port 6. That is, in the substrate holding device 101 of the second embodiment, the first partition is configured to be composed of two adjacent partitions. In this embodiment, the outer partition of the two partitions is called the auxiliary partition (second partition). The substrate holding device 101 of this embodiment will be described below with reference to FIG. 6. FIG. 6 is a diagram illustrating the substrate holding device 101 of this embodiment. FIG. 6(A) is a plan view of the substrate holding device 101 as viewed from the +Z direction. FIG. 6(B) is a partial cross-sectional view of the substrate holding device 101 of FIG. 6(A). The configuration of the substrate holding device 101 of this embodiment is similar to that of the substrate holding device 101 of the first embodiment, and therefore the description of the overlapping parts will be omitted.

The chuck 1 of this embodiment includes multiple pin-shaped protrusions 2, a partition wall 5, and a suction port 6, similar to the first embodiment, and may further include an auxiliary partition wall 7 and a suction port 8.

The auxiliary partition 7 is disposed between the partition 5 and the outer peripheral side convex portion 3 disposed adjacent to the partition 5 on the outer peripheral side. That is, it is disposed at a position closer to the outer peripheral side convex portion 3 than the inner peripheral side convex portion 4. The position of the auxiliary partition 7 is determined by comparing the average values of the positions of the convex portions 2 contained in the multiple groups (hereinafter, multiple groups) shown in Example 1. It is preferable to dispose the auxiliary partition 7 as close as possible to the outer peripheral side convex portion 3 disposed adjacent to the partition 5 on the outer peripheral side from the center position of the distance L. In this embodiment, the auxiliary partition 7 is disposed so that u≒1. The position of the partition 5 is disposed so as to satisfy u<0.5, as in Example 1. The height of the auxiliary partition 7 is formed lower than the height of the outer peripheral side convex portion 3 contained in each of the multiple groups. The height of the outer peripheral side convex portion 3 contained in each of the multiple groups is, for example, an average height. The height of the auxiliary partition 7 may also be lower than the height of a specific outer peripheral side convex portion 3, for example, the outer peripheral side convex portion 3 having the lowest height among the outer peripheral side convex portions 3 contained in each of the multiple groups.

The suction port 8 has the same function as the suction port 6 in Example 1, and is formed between the partition 5 and the auxiliary partition 7. The suction port 8 is connected to the suction unit by a flow path such as a pipe, similar to the suction port 6 in Example 1. Furthermore, the suction unit in the substrate holding device 101 in this example may have valves (switching valves) (not shown) that open and close the flow path for suction, in the flow paths connecting the suction port 6 and the suction port 8 to the suction unit. In this example, the valve arranged between the suction port 6 and the suction unit is referred to as the first valve, and the valve arranged between the suction port 8 and the suction unit is referred to as the second valve.

In this embodiment, when the substrate 110 is held by suction on the chuck 1, it is sucked through the suction ports 6 and 8. The suction process of the substrate 110 in this embodiment is described below. The suction process is controlled by a control unit (not shown) of the substrate holding device 101 executing a computer program.

First, the control unit (not shown) sends an operation command to the suction unit to start suction (exhaust). When the suction unit starts suction, it sucks the space between the back surface of the substrate 110 and the chuck 1 via suction ports 6 and 8. As a result, the area inside the auxiliary partition 7 of the substrate 110 becomes the suction area, generating a larger suction force and making it possible to correct the warp even in a substrate with a large warp. Note that distortion occurs when the warp of the substrate 110 is corrected and suction is completed.

Next, the control unit (not shown) controls the second valve to stop suction of the area through the suction port 8. This opens the space between the partition 5 and the auxiliary partition 7 to the atmosphere from the suction port 8, and the area being sucked transitions from the partition 5, which is the area through the suction port 6, to an area inside the substrate 110, thereby reducing distortion. Note that various controls in these suction processes may be performed by the control unit 109.

Once the substrate 110 has been corrected, there is a low probability that it will return to its original state even if the suction force on the outer periphery (outer periphery) of the substrate 110 is stopped or reduced. Therefore, distortion is kept small.

As described above, in this embodiment, in addition to reducing distortion as in the first embodiment, it is possible to reduce warping of the substrate 110. This makes it possible to provide a chuck that can adsorb and hold the substrate 110 in an optimal state when performing processes such as pattern formation.

In addition, in some substrates 110 with large warpage, the warpage may return when the suction port 8 is opened to the atmosphere. In this case, a negative pressure of about α × minus 1 atmosphere (α is an integer smaller than 1) may be applied by the suction unit through the suction port 8 depending on the state of the warpage of the substrate 110. Alternatively, before the suction unit sucks the space between the back surface of the substrate 110 and the chuck 1, the pressure from the suction port 8 is set to a negative pressure of about minus 1 atmosphere, and the pressure from the suction port 8 is set to a negative pressure of α × minus 1 atmosphere (α is an integer smaller than 1). This eliminates the need to switch between before and after the correction of the substrate 110, and the warpage will not return.

Example 3
In this embodiment, a chuck capable of reducing distortion can be provided by setting the heights of the inner peripheral side convex portion 4 and the outer peripheral side convex portion 3, which will be described later, in a predetermined relationship. The substrate holding device 101 of this embodiment will be described in detail below with reference to FIGS.

Figure 7 is a diagram illustrating the substrate holding device 101 of this embodiment. Figure 7(A) is a plan view of the substrate holding device 101 as viewed from the +Z direction. Figure 7(B) is a partial cross-sectional view of the substrate holding device 101 of Figure 7(A). Below, the substrate holding device 101 of this embodiment will be described in detail with reference to Figure 7. The substrate holding device 101 of this embodiment can include a chuck 1, a suction unit (not shown), and a control unit.

The chuck 1 is circular and has a smaller diameter than the substrate 110, and may include a plurality of pin-shaped protrusions 2, a partition (first partition) 5, and a suction port (first suction port) 6. The chuck 1 is placed on the substrate stage 102.

The protrusions 2 are pin-shaped protrusions arranged in multiple numbers on the bottom of the chuck 1, and when the substrate 110 is placed on the chuck 1, the back surface of the substrate 110 abuts against the upper surface of the protrusions 2. The protrusions 2 are arranged in a lattice pattern at a predetermined distance L (mm) on the bottom of the chuck 1. The diameter of the protrusions 2 varies depending on the specifications of the chuck 1, but a typical diameter is about φ0.2 mm. In addition to the lattice pattern, the protrusions 2 can also be arranged concentrically or at an angle, for example, in a lattice pattern with a 60-degree staggered pattern. They can also be arranged randomly, or a combination of these.

The convex portion 2 may include a plurality of pin-shaped convex portions (outer peripheral convex portion, first convex portion) 3, a plurality of pin-shaped convex portions (inner peripheral convex portion, second convex portion) 4, and a plurality of pin-shaped convex portions (third convex portion) different from the outer peripheral convex portion 3 and the inner peripheral convex portion 4. The outer peripheral convex portion 3 is arranged outside the partition wall 5 so as to abut against the back surface in the outer peripheral direction of the substrate 110. The outer peripheral convex portion 3 is a convex portion arranged in multiple on the outer circumference with the same radius as the substrate 110. The outer peripheral convex portion 3 illustrated in FIG. 7 is arranged on the outermost side (outermost circumference) of the chuck 1. The inner peripheral convex portion 4 is arranged inside the partition wall 5 so as to abut against the back surface in the inner peripheral direction of the substrate 110. The inner peripheral convex portion 4 is arranged in multiple on the inner circumference with the same radius as the substrate 110. The inner peripheral convex portion 4 illustrated in FIG. 7 is arranged next to the outer peripheral convex portion 3 arranged at the bottom on the outermost side, sandwiching the partition wall 5. In this embodiment, the multiple protrusions 2, excluding the third protrusion, are configured to be composed of multiple groups, each group being made up of an outer circumferential side protrusion 3 arranged on the outside of the partition wall 5 and an inner circumferential side protrusion 4 arranged on the inside of the partition wall 5, adjacent to the outer circumferential side protrusion 3 with the partition wall 5 in between. As will be described later, the outer circumferential side protrusions 3 included in each of the multiple groups are made to have a lower height than the inner circumferential side protrusions 4.

At least one partition 5 is arranged in a circular ring shape on the bottom of the chuck 1 so as to surround a portion of the multiple protrusions 2. The suction port 6 is a through hole formed in the chuck 1, and in this embodiment, it functions as a suction port when the suction unit described later sucks (exhausts) the space between the back surface of the substrate 110 and the chuck 1. Note that while only one suction port 6 is provided in FIG. 7, this is not limiting and one or more suction ports 6 may be formed in the chuck 1.

The suction unit is a vacuum source (not shown) configured to be able to suck the space between the back surface of the substrate 110 and the chuck 1 by vacuum suction or the like. The suction unit starts operating in response to a signal from the control unit 109, and can suck the space between the back surface of the substrate 110 and the chuck 1 through a flow path such as a pipe connected to the suction unit and the suction port 6, thereby adsorbing the substrate 110 to the chuck 1. Note that the suction unit is not limited to being disposed in the substrate holding device 101, and may be disposed outside the substrate holding device 101 or outside the exposure device 100.

Next, the height of the outer circumferential projection 3 included in each of the aforementioned multiple groups (hereinafter, multiple groups) is ho. The height of the inner circumferential projection 4 included in each of the multiple groups is hi, and the desirable value of ho will be described below with reference to Figures 8 and 9. In this embodiment, ho is the average height of the outer circumferential projection 3 included in each of the multiple groups, and hi is the average height of the inner circumferential projection 4 included in each of the multiple groups. Figure 8 is a diagram illustrating a material mechanics model of a cantilever beam in the case where the outer circumferential projection 3 of this embodiment is eliminated. The model shown in Figure 8 is a cantilever beam. Figure 9 is a diagram illustrating a cross-sectional view of the chuck 1 of this embodiment.

Figure 9 shows a model 2min of the deflection of the substrate 110 when the outer peripheral convex portion 3 as shown in Figure 8 is eliminated, and a model 2j of the deflection of the substrate 110 when ho = hi.

9, the inclination of the deflection model is dy/dx, the deflection is y, the radial position of the inner circumference side convex portion 4 as a reference is x, and the distance between the outer circumference side convex portion 3 and the inner circumference side convex portion 4 included in each of the multiple groups is L. As a result, the inclination dy/dx with respect to u=x/L can be expressed by the following formula (16), and the deflection y can be expressed by the following formula (17).

上記式（１８）は、ｈｏをｈｉ－（ＰｖＬ^４）／（Ｅｈ^３）よりも小さくすると、基板１１０の裏面が外周側凸部３の支持面に触れなくなることを示している。そのため、以下の式（１９）を満たすことで、ｈｉ＝ｈｏとしたときよりも傾斜ｄｙ／ｄｘを低減することができ、ディストーションを低減することができる。

When u=1, y _max can be expressed by the following equation (18).

The above formula (18) indicates that when ho is made smaller than hi-( ^PvL4 )/( ^Eh3 ), the back surface of the substrate 110 does not come into contact with the supporting surface of the outer circumferential convex portion 3. Therefore, by satisfying the following formula (19), the slope dy/dx can be reduced more than when hi=ho, and distortion can be reduced.

The height of the partition 5 is lower than the inner circumferential side protrusion 4 included in each of the multiple groups, and is equal to or lower than the outer circumferential side protrusion 3 included in each of the multiple groups. If the partition 5 is made higher than the outer circumferential side protrusion 3 included in each of the multiple groups, the partition 5 will perform the same function as the outer circumferential side protrusion 3 included in each of the multiple groups. The partition 5 is placed at a position closer to the outer circumferential side protrusion 3 included in each of the multiple groups than the inner circumferential side protrusion 4 included in each of the multiple groups. The placement position of the partition 5 in this case is determined by comparing the average positions of the protrusions included in each of the multiple groups. It is preferable to place the partition 5 as close as possible to the outer circumferential side protrusion 3 included in each of the multiple groups, and in this embodiment, the partition 5 is placed so that u ≒ 1.

As described above, in this embodiment, distortion can be reduced by setting the height of hi relative to ho so as to satisfy hi-ho<(PvL ⁴ )/(Eh ³ ). This makes it possible to provide a chuck capable of suction-holding the substrate 110 in an optimal state when performing processes such as pattern formation.

For example, if Pv = 0.1013 MPa, L = 2 mm, and E = 160 GPa are substituted into the above formula (18), then when h = 0.7 mm, ymax = 44.3 nm. In this case, distortion can be reduced by designing hi-ho to be smaller than about 45 nm, for example.

Example 4
The substrate holding device 101 of this embodiment is a substrate holding device in which the cross-sectional area of the outer circumferential side convex portion 3 included in each of the plurality of groups (hereinafter, the plurality of groups) shown in the embodiment 3 is made smaller than the cross-sectional area of the inner circumferential side convex portion 4 included in each of the plurality of groups. Note that the configuration of the substrate holding device 101 is similar to that of the substrate holding device 101 of the embodiment 3, and therefore a description of the overlapping parts will be omitted.

In this embodiment, if the cross-sectional area of the outer circumferential convex portion 3 included in each of the multiple groups is So, and the cross-sectional area of the inner circumferential convex portion 4 included in each of the multiple groups is Si, the outer circumferential convex portion 3 and the inner circumferential convex portion 4 are designed and processed so that Si>So. This reduces the processing resistance of the outer circumferential convex portion 3 during processing, making it easier to process the convex portions. In this embodiment, So is the average value of the cross-sectional areas of the outer circumferential convex portions 3 included in each of the multiple groups, and Si is the average value of the cross-sectional areas of the inner circumferential convex portions 4 included in each of the multiple groups.

Furthermore, the reduction in processing resistance increases the amount of outer peripheral convex portion 3 that is included in each of the multiple groups that is removed, which contributes to hi>ho. Furthermore, the vertical rigidity of the outer peripheral convex portion 3 that is included in each of the multiple groups is smaller than that of the inner peripheral convex portion 4 that is included in each of the multiple groups. This increases the amount of vertical compression of the substrate 110 when sucked by the suction portion, which contributes to hi>ho. Note that, although lapping may be considered as an example of processing the convex portion 2, other methods may be used as long as they can be used to process the convex portion 2 so that Si>So.

As described above, in this embodiment, the outer circumferential convex portion 3 included in each of the multiple groups and the inner circumferential convex portion 4 included in each of the multiple groups are processed so that Si>So. This improves the processing accuracy and shortens the processing time. Furthermore, as in the third embodiment, distortion can be reduced, and a chuck can be provided that can adsorb and hold the substrate 110 in an optimal state when performing processing such as pattern formation.

Example 5
The substrate holding device 101 of this embodiment is a substrate holding device further provided with an auxiliary partition (second partition) 7 as a partition different from the partition (first partition) 5 in the chuck 1 of the third embodiment, and a suction port (second suction port) 8 which is a suction port different from the suction port 6. That is, in the substrate holding device 101 of the fifth embodiment, the first partition is configured to be composed of two adjacent partitions. In this embodiment, the outer partition of the two partitions is called the auxiliary partition (second partition). The substrate holding device 101 of this embodiment will be described below with reference to FIG. 10. FIG. 10 is a diagram illustrating the substrate holding device 101 of this embodiment. FIG. 10(A) is a plan view of the substrate holding device 101 as viewed from the +Z direction. FIG. 10(B) is a partial cross-sectional view of the substrate holding device 101 of FIG. 10(A). The configuration of the substrate holding device 101 of this embodiment is similar to that of the substrate holding device 101 of the third embodiment, and therefore the description of the overlapping parts will be omitted.

The chuck 1 of this embodiment includes multiple pin-shaped protrusions 2, a partition 5, and a suction port 6, similar to the third embodiment, and may further include an auxiliary partition 7 and a suction port 8.

The auxiliary partition 7 is disposed between the partition 5 and the inner circumferential protrusion 4 disposed adjacent to the partition 5 on its inner circumferential side. The auxiliary partition 7 is preferably disposed closer to the inner circumferential protrusion 4 disposed adjacent to the partition 5 on its inner circumferential side than the center position of the distance L. For example, it is disposed so that u<0.5 is satisfied. Note that the partition 5 is disposed so that u≈1, as in Example 3.

The height of the auxiliary partition 7 is formed lower than the height of the inner circumferential side protrusions 4 included in each of the multiple groups. The height of the inner circumferential side protrusions 4 included in each of the multiple groups is, for example, an average height. The height of the auxiliary partition 7 may also be lower than the height of a specific inner circumferential side protrusion 4, for example, the inner circumferential side protrusion 4 with the lowest height among the inner circumferential side protrusions 4 included in each of the multiple groups. The height of the auxiliary partition 7 may also be formed about 1 to 2 μm lower than the upper surface of the multiple protrusions 2. Even if it is formed about 1 to 2 μm lower, with a gap of about 1 to 2 μm, the decrease in vacuum pressure when the suction part sucks the space (area) between the back surface of the substrate 110 and the chuck 1 to suction and hold the substrate 110 is slight and does not cause a problem. Also, even if foreign matter such as dust or particles with a diameter smaller than the difference of about 1 to 2 μm adheres to the auxiliary partition 7, the probability that the adhered foreign matter will come into contact with the back surface of the substrate 110 is very low. Therefore, there is no problem if the height of the auxiliary partition 7 is formed about 1 to 2 μm lower than the upper surfaces of the multiple protrusions 2.

The suction port 8 has the same function as the suction port 6 in Example 3, and is formed between the partition 5 and the auxiliary partition 7. The suction port 8 is connected to the suction unit by a flow path such as a pipe, similar to the suction port 6 in Example 3. Furthermore, the suction unit in the substrate holding device 101 in this example may have valves (switching valves) (not shown) that open and close the flow path for suction, in the flow paths connecting the suction port 6 and the suction port 8 to the suction unit. In this example, the valve arranged between the suction port 6 and the suction unit is referred to as the first valve, and the valve arranged between the suction port 8 and the suction unit is referred to as the second valve.

In this embodiment, when the substrate 110 is held by suction on the chuck 1, it is sucked through the suction ports 6 and 8. The suction process of the substrate 110 in this embodiment is described below. The suction process is controlled by a control unit (not shown) of the substrate holding device 101 executing a computer program.

First, the control unit (not shown) sends an operation command to the suction unit to start suction (exhaust). When the suction unit starts suction, it sucks the space between the back surface of the substrate 110 and the chuck 1 via suction ports 6 and 8. As a result, the area inside the partition wall 5 on the substrate 110 becomes the suction area, generating a larger suction force and making it possible to correct the warp even in a substrate with a large warp. Note that distortion occurs when the warp of the substrate 110 is corrected and suction is completed.

Next, the control unit (not shown) controls the second valve to stop suction of the area through the suction port 8. This opens the space between the partition 5 and the auxiliary partition 7 to the atmosphere from the suction port 8, and the area being sucked transitions from the auxiliary partition 7, which is the area through the suction port 6, to an area inside the substrate 110, thereby reducing distortion. Note that various controls in these suction processes may be performed by the control unit 109.

Once the substrate 110 has been corrected, there is a low probability that it will return to its original state even if the suction force on the outer periphery (outer periphery) of the substrate 110 is stopped or reduced. Therefore, distortion is kept small.

As described above, in this embodiment, in the same way as in the third embodiment, in addition to reducing distortion, it is possible to reduce warping of the substrate 110. This makes it possible to provide a chuck that can adsorb and hold the substrate 110 in an optimal state when performing processes such as pattern formation.

In addition, in some substrates 110 with large warpage, the warpage may return when the suction port 8 is opened to the atmosphere. In this case, a negative pressure of about α × minus 1 atmosphere (α is an integer smaller than 1) may be applied by the suction unit through the suction port 8 depending on the state of the warpage of the substrate 110. Alternatively, before the suction unit sucks the space between the back surface of the substrate 110 and the chuck 1, the pressure from the suction port 8 is set to a negative pressure of about minus 1 atmosphere, and the pressure from the suction port 8 is set to a negative pressure of α × minus 1 atmosphere (α is an integer smaller than 1). This eliminates the need to switch between before and after the correction of the substrate 110, and the warpage will not return.

Also, for example, at least two of the substrate holding devices 101 of the above embodiments may be combined. In other words, the substrate holding device 101 may use a chuck that combines at least two of the chucks 1 illustrated in Figures 3, 6, 7, and 10.

In the above embodiments, the protrusions 2 are arranged in a grid pattern at a predetermined distance from the bottom of the chuck 1, but this is not limited to the above. For example, the distance between the protrusions 2 on the inner and outer circumferential sides of the substrate 110 may be set arbitrarily. Furthermore, the distance may not be uniform, but may be non-uniform.

In addition, the chuck 1 in each of the above embodiments is of a vacuum suction type, but is not limited to this. For example, it may be of an electrostatic chuck type, or may be of a combination of a vacuum suction type and an electrostatic chuck type. In such cases, the vacuum pressure P in this embodiment may be replaced with the suction force of the other type, or with the vacuum pressure added thereto.

In addition, the chuck 1 in each of the above embodiments is a pin chuck, but it is not limited to this and may have other shapes. For example, it may be a so-called ring-shaped chuck in which concentric annular recesses that are suction grooves and concentric annular protrusions that are substrate support surfaces are alternately arranged. In addition, the partitions are not limited to only the partition 5 and auxiliary partition 7, and partitions other than the partition 5 and auxiliary partition 7 may be arranged in the chuck 1.

<Example of article manufacturing method>
Next, an embodiment of a device manufacturing method using the exposure apparatus 100 of each of the above-mentioned embodiments will be described. Fig. 11 shows a manufacturing flow of a microdevice (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). In step 1 (circuit design), a pattern for the device is designed.

In step 2 (mask production), a mask (mold, model) is produced on which the designed pattern is formed. Meanwhile, in step 3 (wafer production), a wafer (substrate) is manufactured using materials such as silicon and glass. Step 4 (wafer processing) is called the front-end process, in which the mask and wafer prepared above are used to form the actual circuit on the wafer using lithography technology.

The next step, 5 (assembly), is called the post-process, in which the wafers produced in step 4 are used to create semiconductor chips, and includes processes such as assembly (dicing, bonding) and packaging (chip encapsulation). In step 6 (inspection), the semiconductor devices produced in step 5 are subjected to tests to confirm their operation and durability. After going through these processes, the semiconductor devices are completed and are then shipped (step 7).

Figure 12 shows a detailed flow of the above wafer process. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), electrodes are formed on the wafer by deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist processing), resist is applied to the wafer. In step 16 (exposure), the circuit pattern of the mask is aligned in multiple pattern formation areas on the wafer and exposed by exposure using the projection exposure apparatus described above. In step 17 (development), the exposed wafer is developed. In step 18 (etching), the parts other than the developed resist image are scraped off. In step 19 (resist stripping), the resist that is no longer needed after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

In this way, the device manufacturing method using the chuck 1 of this embodiment suppresses distortion and warping of the substrate, improving the precision and yield of the device. This makes it possible to stably manufacture highly integrated devices that were previously difficult to manufacture at low cost.

<Other Examples>
The present invention has been described in detail above based on its preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications are possible based on the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

In addition, a computer program that realizes part or all of the functions of the above-mentioned embodiments of the control may be supplied to the substrate holding device 101, substrate processing apparatus, etc. via a network or various storage media. Then, a computer (or a CPU, MPU, etc.) in the substrate holding device 101, substrate processing apparatus, etc. may read and execute the program. In this case, the program and the storage medium on which the program is stored constitute the present invention.

101 Substrate holding device 1 Chuck 2 Convex portion 3 Convex portion (outer peripheral convex portion)
4. Convex portion (inner peripheral convex portion)
5 Partition wall 6 Suction port

Claims (20)

A chuck for suction-holding a substrate,
a plurality of protrusions that come into contact with the rear surface of the substrate that is held by suction;
An annular partition;
a bottom portion on which the plurality of protrusions and the partition wall are disposed,
the plurality of convex portions are constituted by a plurality of groups, each group being a first convex portion disposed on an outer side of the partition wall and a second convex portion disposed on an inner side of the partition wall and adjacent to the first convex portion with the partition wall interposed therebetween;
When the distance between the first convex portion and the second convex portion included in each of the plurality of groups is L and the distance between the second convex portion and the partition wall is s,
s/L<0.5
A chuck characterized by satisfying the above. The chuck according to claim 1, characterized in that the partition has a height lower than the second protrusions included in each of the plurality of groups. The chuck according to claim 1 or 2, characterized in that the partition is composed of two adjacent partitions. The chuck according to claim 3, characterized in that the outer partition of the double partition has a height lower than the first protrusions included in each of the plurality of groups. The chuck according to any one of claims 1 to 4, characterized in that the bottom portion is provided with a first suction port for sucking the inner periphery side of the partition. The chuck according to claim 3 or 4, characterized in that the bottom portion is provided with a second suction port for sucking between the double partition walls. The chuck according to any one of claims 1 to 6, characterized in that the partition has a diameter smaller than the diameter of the substrate. The chuck according to any one of claims 1 to 7, characterized in that it has a third protrusion that is different from the plurality of protrusions. When the height of the first convex portion included in each of the plurality of groups is ho and the height of the second convex portion included in each of the plurality of groups is hi,
hi>ho
9. The chuck according to claim 1, wherein the following is satisfied: The chuck according to claim 9, characterized in that the first protrusions included in each of the plurality of groups are the protrusions arranged on the outermost side of the plurality of protrusions arranged on the bottom. The chuck according to claim 9 or 10, characterized in that the height of the partition is equal to or less than the height of the second protrusions included in each of the plurality of groups. When a cross-sectional area of the first convex portion included in each of the plurality of groups is So and a cross-sectional area of the second convex portion included in each of the plurality of groups is Si,
Si>So
12. The chuck according to claim 9, wherein the following is satisfied: The chuck according to any one of claims 9 to 12, characterized in that the partition is disposed at a position closer to the first convex portion included in each of the plurality of groups than the second convex portion included in each of the plurality of groups. The chuck according to any one of claims 9 to 13, characterized in that the partition is composed of two adjacent partitions. The chuck according to claim 14, characterized in that the outer partition of the double partition has a height lower than the second protrusions included in each of the plurality of groups. 2. A substrate holding device for suction-holding a substrate, comprising the chuck according to claim 1,
When the distortion indicating the distortion of the substrate is dx, the Young's modulus of the substrate is E, the thickness of the substrate is h, and the suction pressure on the substrate is Pv,
The arrangement position of the partition wall is
dx < correction coefficient × (h/2) × PvL ³ / 4Eh ³ (3u ⁴ − 4u ³ )
A substrate holding device comprising: When the flatness of the substrate is dz and the dimension of the substrate protruding outward from the first convex portion arranged at the outermost periphery is oh,
The arrangement position of the partition wall is
dz < correction coefficient × oh × PvL ³ / 4Eh ³ (3u ⁴ - 4u ³ )
17. The substrate holding device according to claim 16, wherein the above-mentioned condition is satisfied. The substrate holding device according to claim 16 or 17, characterized in that it is provided with a valve that opens and closes a flow path for sucking the inner circumference side of the partition wall, and a control unit that controls the valve. A substrate processing apparatus that performs a pattern forming process on the substrate held by suction using the substrate holding device according to any one of claims 16 to 18. A pattern forming process for forming a pattern on a substrate by using the substrate processing apparatus according to claim 19;
a processing step of processing the substrate on which the pattern has been formed in the pattern forming step;
manufacturing an article from the substrate processed in the processing step;
A method for producing an article, comprising:

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