JP2023065133A - Substrate holding plate, production method of device, and exposure equipment - Google Patents

Abstract

To provide a substrate holding plate having high peeling resistance, with a reflectivity on the surface of the substrate holding plate being suppressed.SOLUTION: A substrate holding plate includes a first layer and a second layer having an interface with the first layer. The first layer and the second layer are made of diamond-like carbon. The refractive index of the first layer at a wavelength is higher than the refractive index of the second layer at the wavelength. The distance from the second layer to the uppermost surface of the substrate holding plate is less than the thickness of the first layer.SELECTED DRAWING: Figure 2

Description

The present invention relates to a substrate holding board.

An exposure apparatus performs exposure processing on a substrate made of silicon, glass, SiC, or the like. In these apparatuses, the surface on which the substrate is placed wears due to the use of the substrate holding plate over time, and as a result, the reflectance on the surface of the substrate holding plate increases. There was a problem that the area was irradiated. Therefore, Patent Document 1 proposes a configuration in which a substrate holding plate is coated with a DLC (Diamond Like Carbon) film, and the surface of the DLC film is coated with an inorganic coating agent in this order.

JP 2015-94002 A

The substrate holding board of Patent Document 1 has a problem that the adhesion between the DLC film and the inorganic coating agent is not sufficient, and the inorganic transparent thin film is easily peeled off.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a substrate holding board having high peel resistance while suppressing the reflectance on the surface of the substrate holding board.

A first means for solving the above problems is a substrate holding board having a first layer and a second layer forming an interface with the first layer, the first layer and the second layer comprising: made of diamond-like carbon, the refractive index of the first layer at a certain wavelength is higher than the refractive index of the second layer at the wavelength, and the distance from the second layer to the uppermost surface of the substrate holding board is the It is characterized by being smaller than the thickness of the first layer.

A second means for solving the above problems is a substrate holder having a first layer and a second layer forming an interface with the first layer, wherein the first layer is made of diamond-like carbon, The second layer is made of silicon carbide, the refractive index of the first layer at a certain wavelength is higher than the refractive index of the second layer at the wavelength, and the distance from the second layer to the top surface of the substrate holder is higher than that of the second layer at the wavelength. The distance is characterized by being less than the thickness of the first layer.

According to the present invention, it is possible to provide an advantageous technique for improving the peeling resistance of the substrate holding board while suppressing the reflectance on the surface of the substrate holding board.

The perspective view of a board|substrate holding board. (a) is a schematic diagram for explaining the substrate holding board according to the first embodiment, (b) is an enlarged view of a portion surrounded by a circle 11, and (c) is a circle 12 in (b). It is the figure which expanded the enclosed part. (a) is a schematic diagram for explaining a substrate holding board according to a second embodiment, (b) is an enlarged view of a portion surrounded by a circle 11, and (c) is a diagram shown by a circle 12 in (b). It is the figure which expanded the enclosed part. (a) is a schematic diagram for explaining a substrate holding board according to a third embodiment, and (b) is an enlarged view of a portion surrounded by a circle 13. FIG. Formula describing the theoretical value of reflectance. 1 is a schematic diagram of an exposure apparatus according to this embodiment; FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the form described below is one embodiment of the invention, and is not limited to this. In addition, in the following description and drawings, common reference numerals are attached to structures common to a plurality of drawings. Common configurations will be described with reference to a plurality of drawings, and descriptions of configurations to which common reference numerals are assigned will be omitted as appropriate.

FIG. 1(a) shows a perspective view of a substrate holding board of a first example according to the present embodiment. A substrate holding board 1 in this embodiment has a base 2 and a projection 3 on the base 2 . One of the two main surfaces (surface and back surface) of the substrate holding board 1 (referred to as the surface for convenience) is the uppermost surface 32 , and the projection 3 is located on the uppermost surface 32 side with respect to the base 2 . Although provided, the projection 3 can be omitted. The uppermost surface 32 is the surface on which the substrate 7 is placed, which is in contact with the atmosphere around the substrate holding board 1 , and is not necessarily the surface in contact with the substrate 7 . Top surface 32 may also function as a substrate holding surface for holding substrate 7, for example.

FIG. 1(b) shows a perspective view when the substrate 7 is placed on the substrate holding board 1 of FIG. 1(a). The base 2 and the protrusion 3 provided on the base 2 hold the substrate 7 . By supporting the substrate 7 with the projections 3, the contact area between the substrate holding board 1 and the substrate 7 is reduced, and damage to the substrate 7 can be suppressed as compared with the case where the projections 3 are not provided. . The substrate 7 placed on the substrate holding board 1 of the first example is a substrate 7 used for manufacturing electronic devices. The substrate 7 can form part of the electronic device, but may be removed during the manufacture of the electronic device and may not form the electronic device. The substrate 7 can be, for example, a glass substrate, a resin substrate, or a sapphire substrate used for manufacturing organic EL displays, liquid crystal displays, solar cell panels, and the like.

The substrate holding board 1 of this example is provided with a suction hole portion 4 through which the substrate 7 is vacuum-sucked, but the suction hole portion 4 may be omitted.

FIG. 1(c) shows a perspective view of a substrate holding board of a second example according to the present embodiment. FIG. 1(d) shows a perspective view when the substrate 7 is placed on the substrate holding board 1 of FIG. 1(c). The substrate holding board 1 of the second example differs from that shown in FIG. The substrate 7 mounted on the substrate holding table 1 of the second example can be, for example, a semiconductor substrate such as a Si wafer or SiC wafer, or an insulator substrate such as a glass wafer, a plastic wafer, or sapphire.

The substrate holding board 1 shown in FIGS. 1(a) to 1(d) can be used in various electronic device manufacturing apparatuses. For example, it can be used to hold the substrate 7 in an exposure apparatus that exposes a photoresist applied on the substrate 7 . It can be used not only for the exposure apparatus, but also for the film formation apparatus, the etching apparatus, and the like.

As shown in FIG. 1(e), a plurality of substrate holding boards 1 can be arranged and used as a substrate holder 111. As shown in FIG.

<First embodiment>
Next, the first embodiment will be described with reference to FIG.

FIG. 2(a) is a cross-sectional view enlarging the area surrounded by circle 10 in FIG. 1(a) or FIG. 1(c), and FIG. 2(c) is an enlarged view of the range surrounded by a circle 12 in FIG. 2(b).

The substrate holding board 1 of this embodiment has a base portion 2 and projections 3 as described with reference to FIG. 1(a) or FIG. 1(c). The upper surface of the protrusion 3 has a coating layer 51 forming an interface with the protrusion 3 and a coating layer 52 having a lower refractive index and a higher hydrogen content than the coating layer 51 . are both composed of DLC (diamond-like carbon). DLC is a material that exhibits characteristics intermediate between those of diamond and graphite, which are mainly composed of carbon. Here, the uppermost surface 32 is formed by a light coating layer 52 provided on the upper surface of the projection 3 and the upper surface of the base 2 . The protrusion 3 can be omitted, and if the protrusion 3 is omitted, the covering layer 51 is provided on the upper surface of the base 2 and the covering layer 52 is provided on the upper surface of the covering layer 51 . That is, in this embodiment, the base 2 and the coating layer 51, and the coating layer 51 and the coating layer 52 respectively form an interface. In the present embodiment, the two layers of the coating layer 51 and the coating layer 52 are laminated. It is also possible to provide three or more layers.

The base 2 will be explained. The base 2 is composed of a component 21 , a component 22 , and a component 23 . Each of component part 21, component part 22, and component part 23 is made of the same material. The components 21, 22 and 23 made of at least the same material are called base materials, and the parts made of the same material as the above materials are also called base materials. Components 21, 22, and 23 are positioned on the same plane. The lower surfaces of the constituent parts 21 , 22 and 23 are also positioned on the same plane, forming a rear surface 24 opposite to the uppermost surface 32 . The component 22 is positioned between the component 21 and the component 23 . A coating layer 51 and a coating layer 52 may be provided on the component parts 21 and 23, and preferably from the viewpoint of reducing the reflectance.

The protrusion 3 will be explained. The projecting portion 3 exists on the constituent portion 22 of the base portion 2, and the projecting portion 3 does not exist on the constituent portions 21 and 23, and a space is provided. The protrusion 3 exists between the space above the component 21 and the space above the component 23 , and the space exists between the two protrusions 3 .

The projecting portion 3 has a constituent portion 31 made of the same material as the base portion 2, and a coating layer 51 forming an interface with the projecting portion 3 and a coating layer 52 forming an interface with the covering layer 51 are formed on the upper surface of the projecting portion 3. is provided. The constituent part 31 is also a base material.

Next, the coating layers 51 and 52 will be described. In the present embodiment, the coating layer 51 and the coating layer 52 are DLC, and by making the coating layer 52 lower in refractive index than the coating layer 51, the coating layer 52 functions as an antireflection film and reflects light. rate can be reduced. Moreover, by laminating the coating layer 52 having a higher hydrogen content than the coating layer 51, the material compatibility between the coating layers 51 and 52 is improved, and the separation resistance can be improved. From the viewpoint of improving peeling resistance, it is preferable that there is air directly above the coating layer 52 . That is, the coating layer 52 is in contact with the atmosphere (for example, air or inert gas) around the substrate holding plate 1 and exists between the coating layer 51 and the atmosphere. When the substrate 7 is placed, the coating layer 52 provided on the projecting portion 3 contacts and holds the substrate 7 .

The covering layer 52 exists within a distance H from the top surface 32, and the distance H is smaller than the thickness D of the covering layer 51 (D>H). That is, the coating layer 52 exists closer to the uppermost surface 32 than the coating layer 51 is. In this embodiment, the distance H is zero because the covering layer 52 forms the top surface 32 .

The coating layer 51 is made of ta-C (tetrahedral amorphous-carbon) or a-C:H (hydrogenated amorphous-carbon) with a low hydrogen content among DLCs from the viewpoint of a higher refractive index and a lower hydrogen content than the coating layer 52. is preferred. Among DLCs, aC:H is preferable for the coating layer 52 from the viewpoint of a lower refractive index and a higher hydrogen content than the coating layer 51 . The hydrogen concentration of ta-C is preferably less than 10at%, more preferably less than 5at%. The hydrogen concentration of aC:H is preferably 10 at % or more and less than 50 at %. More preferably, it is 21 to 26 at %. If the hydrogen content is 21 to 26 at %, good film quality (high hardness and high toughness) can be obtained in forming the coating layer 52 . The hardness of DLC decreases as the hydrogen concentration increases. Therefore, in this embodiment, the coating layer 51 has higher hardness than the coating layer 52 . The silicon content of coating layers 51 and 52 is the same, preferably 0 at %.

DLC can be defined by the ratio of sp2 hybrid orbital and sp3 hybrid orbital of CC bond and hydrogen content, and the ratio of sp2 hybrid orbital and sp3 hybrid orbital is 0.1 to 1.0 for ta-C. 9, aC:H is 0.14 to 3.0.

In this embodiment, the coating layer 51 is, for example, the first layer, and the coating layer 52 is, for example, the second layer. The hardness of the coating layer 51 is preferably 20 GPa or more and 27 GPa or less, and the hardness of the coating layer 52 is 10 GPa or more and 20 GPa or less.

ta-C is deposited by PVD (Physical Vapor Deposition) such as arc ion plating. Among arc ion plating, FCVA (Filtered Cathodic Vacuum Arc) is more preferable from the viewpoint of reducing droplets (particles with a diameter of several tens of nanometers to several microns that deteriorate the flatness of the film).

aC:H is deposited by a CVD method such as a plasma CVD (Chemical Vapor Deposition) method. The hydrogen content and refractive index of DLC can be controlled by film formation conditions, such as the flow rate of source gas and substrate bias. Hydrogen content in DLC can be analyzed by elastic recoil detection analysis (ERDA). DLC may contain argon. The higher the argon content of the DLC, the lower the refractive index of the DLC, which is effective in suppressing reflection. The argon content of the DLC may be less than 10 at %, preferably 1 at % or more. In addition, at % which shows the content of an element is atom % or at %. The content (concentration) of an element can be analyzed by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

The refractive index of the coating layer 51 is preferably 1.8 or more and 3.0 or less, more preferably 2.0 or more and 2.7 or less. The refractive index of the coating layer 52 is preferably 1.3 or more and 2.5 or less, more preferably 1.6 or more and 2.2 or less, but is set lower than that of the coating layer 51 .

The thickness D of the coating layer 51 is required to suppress wear, and is preferably 500 nm or more. However, if the thickness is 10 μm or more, cracks are likely to occur, so the thickness is preferably less than 10 μm.

The thickness of the coating layer 52 is preferably smaller than the thickness of the coating layer 51, preferably 10 nm or more, and more preferably 20 nm or more. Moreover, the thickness of the coating layer 52 is preferably less than 500 nm, and more preferably 250 nm or less.

Here, the reflectance on the surface of the substrate holding board will be explained. Light beams with wavelengths of 365 nm (i-line), 405 nm (h-line), 436 nm (g-line), etc. are used in an exposure apparatus for forming fine patterns. The theoretical value of the reflectance R on the surface of the substrate holder can be obtained from the four equations shown in FIG. The parameters of each formula are as follows.
R: reflectance N ₃ : refractive index of air N ₂ : complex refractive index of coating layer 52 with respect to exposure wavelength λ N ₁ : complex refractive index of coating layer 51 with respect to exposure wavelength _NE : coating layer 51 and coating layer 52 Complex refractive index δ when regarded as one layer: Phase difference π: Circumferential constant d: Thickness of coating layer 52 (nm)
λ: Exposure wavelength (nm)
i: imaginary unit

The complex refractive indices of N ₁ to N ₃ are refractive indices considering light absorption. The absorption of light is represented by an extinction coefficient. For example, when the refractive index is 1.7 and the extinction coefficient is 0.3, the complex refractive index is 1.7-0.3i. The refractive index and extinction coefficient can be measured by an ellipsometry method or the like. From the four equations in FIG. 3, it can be seen that if the coating layer 52 and the coating layer 51 have the same extinction coefficient, the refractive index of the coating layer 51 is greater than the refractive index of the coating layer 52, which is advantageous for low reflection. . From the viewpoint of low reflection, the refractive index of the coating layer 51 is preferably 1.2 times or more than the refractive index of the coating layer 52, and although there is no upper limit, it is preferably 2.4 times or less. It is preferable, and 2.0 times or less is more preferable. By forming the coating layer 52 having a refractive index lower than that of the coating layer 51, the coating layer 52 functions as an antireflection film and can sufficiently reduce the reflectance.

The material that constitutes the base material (the base portion 2 and the component portion 31) in this embodiment is black alumina. The thickness of the substrate (base portion 2 and constituent portion 31) is required to ensure the mechanical strength of the substrate holding plate 1, and is, for example, 10 to 100 mm, preferably 60 mm or less. The thickness of the base material (base 2 and component 31) may be 30 mm or less.

The material constituting the base material is not limited to black alumina, and may be alumina, ceramics, zirconia, glass, plastic, metal, or the like.

The protrusions 3 may have any shape and arrangement pitch as long as they can support the substrate 7. Here, the protrusions are truncated cone-shaped or columnar-shaped protrusions. The pitch of the protrusions 3 is, for example, 1 mm or more and 100 mm or less, preferably 10 mm or more and 30 mm or less. The pitch of the projections 3 may be 1 mm or more and 10 mm or less. The height of the projection 3 is, for example, 10 μm or more and 1 mm or less, preferably 0.2 mm or more and 0.8 mm or less. The height of the protrusion 3 may be, for example, 50 μm or more and 0.5 mm or less, or may be 0.3 mm or less.

Next, the suction hole portion 4 according to this embodiment will be described. The suction hole portion 4 sucks and holds the substrate 7 placed on the protrusion 3 , so that the lower opening of the suction hole portion 4 is connected to a vacuum pump (not shown) to remove the air around the protrusion 3 . Suction and decompression were made possible. By providing the projecting portion 3, more air can be sucked than when not provided. Although the side surface of the suction hole portion 4 is coated with the coating layer 51 in this example, it does not need to be coated with the coating layer 51 because it does not face the substrate 7 . Similarly, the coating layer 51 need not be coated on the back surface 24 of the base 2 and the side surface 240 of the base 2 .

<Second embodiment>
A second embodiment will be described with reference to FIG. This embodiment differs from the first embodiment in that the uppermost surface 32 is formed of a coating layer 53 .

FIG. 3(a) is a cross-sectional view enlarging the area surrounded by circle 10 in FIG. 1(a) or FIG. 1(c), and FIG. FIG. 3(c) is an enlarged view of the range surrounded by circle 12 in FIG. 3(b).

The covering layer 52 is within a distance H from the top surface 32 formed by the covering layer 53 , the distance H being less than the thickness D of the covering layer 51 . In this embodiment, the coating layer 53 and the coating layer 52 form an interface, and the coating layer 52 and the coating layer 51 form an interface on the opposite side of the coating layer 53 when viewed from the coating layer 52 . As in this embodiment, one or a plurality of coating layers such as the coating layer 53 may be provided on the coating layer 52 as long as D>H is satisfied.

In this embodiment, the upper surface of the projection 3 has the coating layer 53 and the upper surface of the base 2 has only the coating layers 51 and 52. However, the coating layer 53 is provided on the upper surface of the base 2. It's okay to be. Further, the uppermost surface 32 of the upper surface of the protrusion 3 is the coating layer 53 , while the uppermost surface 32 of the upper surface of the base 2 is the coating layer 52 .

The coating layer 53 preferably has a lower refractive index than the coating layer 52 . By doing so, the reflectance on the surface of the substrate holding board 1 can be reduced as compared with the first embodiment.

<Third Embodiment>
A third embodiment will be described with reference to FIG. This embodiment differs from the first embodiment in that it does not have the protrusion 3 and the uppermost surface 32 is rough.

FIG. 4(a) is a schematic diagram of the substrate holding board 1 according to this embodiment, and FIG. 4(b) is an enlarged view of a portion surrounded by a circle 13 in FIG. 4(a).

By roughening the uppermost surface 32, it is possible to reduce the reflectance on the surface of the substrate holding plate 1 during exposure processing. As a result, fluctuations in irradiation intensity are reduced, and exposure unevenness can be suppressed.

By roughening the surface of the base 2, the interface between the coating layer 51 and the coating layer 52 formed on the surface of the base 2 can also be roughened. Further, when the coating layer 53 is provided, the interface between the coating layers 52 and 53 can also be roughened, and the top surface 32 is most preferably rough. is a rough surface. When the projection 3 is provided, it is preferable that not only the uppermost surface of the projection 3 but also the upper surface of the base 2 be rough. Thereby, the adhesion between the base 2 and the covering layer 51 and between the covering layer 51 and the covering layer 52 can be improved.

In addition, since the contact area with the substrate 7 is smaller than when the uppermost surface 32 is not roughened, there is also the effect of reducing damage to the substrate 7 .

Even if the top surface 32 is rough, the coating layer 52 exists within the distance H from the top surface 32 and is smaller than the thickness D of the coating layer 51 . D>H does not necessarily have to be satisfied by the entire top surface 32 as long as at least a portion of it satisfies D>H. In this embodiment, the distance H is zero because the covering layer 52 forms the top surface 32 .

The arithmetic mean roughness Ra of the rough surface is, for example, 0.4 μm or more and 4.0 μm or less.

Also in this embodiment, it is possible to provide the coating layer 53 as the uppermost surface 32 as in the second embodiment.

<Fourth Embodiment>
A fourth embodiment will be described. This embodiment differs from the first embodiment in that the coating layer 52 is made of silicon carbide. The coating layer 52 of this embodiment is made of silicon carbide, has a lower refractive index than the coating layer 51 , and has a higher silicon content than the coating layer 51 . Since the coating layer 52 contains SiC bonds in the layer, the strength of the layer itself is increased, and the material compatibility with the coating layer 51 made of diamond-like carbon is good, so that the separation resistance can be improved. The coating layer 52 may also contain hydrogen and oxygen. In addition, since the coating layer 52 contains 1 at % or more and 10 at % or less of argon, it is also effective in suppressing the reflectance. The coating layer 52 is formed by PVD such as sputtering or CVD such as plasma CVD. The CVD method is preferable from the viewpoint of reducing the refractive index.

In this embodiment, when the coating layer 51 is ta-C, the hydrogen content of the coating layer 52 is higher than that of the coating layer 51 .

In this embodiment, the coating layer 51 may have a higher refractive index than the coating layer 52, and may be ta-C or aC:H among diamond-like carbons. The silicon content of the coating layer 51 is 5% or less, and may be 0%.

In this embodiment, the hardness of the coating layer 51 is 10 GPa or more and 27 GPa or less, and the hardness of the coating layer 52 is preferably lower than that of the coating layer 51 .

The present invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of the present invention.

FIG. 6 shows a schematic diagram of an exposure apparatus. The optical equipment EQP, which is an exposure apparatus, includes a light source 14 and mirrors 16 and 17 forming an illumination optical system. The optical equipment EQP also includes a reticle stage 19 that supports a reticle 18 as pattern forming means, a projection optical system 25 that projects the pattern formed on the reticle 18, and a substrate holder 1 that supports the substrate 7. . The exposure light 15 from the light source 14 is reflected by the mirrors 16 and 17 of the illumination optical system and guided to the reticle 18, and the exposure light 15 accompanied by the pattern formed on the reticle 18 is condensed by the projection optical system 25. It is projected onto the substrate 7 . The substrate 7 and the substrate holding plate 1 are moved by the substrate moving means 26 and the pattern formed on the reticle 18 by the light source 14 is projected onto the substrate 7 . A photoresist is applied to the substrate 7 and the photoresist is exposed to the exposure light 15 . The substrate 7 may be a semiconductor wafer or a glass substrate for FPD (Flat Panel Display). The exposure light of the exposure device is typically ultraviolet light. The wavelength of the exposure light is 436 nm for the g-line light source and about 365 nm for the i-line light source. It is about 248 nm for a KrF excimer laser light source, about 193 nm for an ArF excimer laser light source, and 10 to 20 nm for an EUV (extreme ultraviolet) light source. The projection optical system may be of a reduced projection type, an equal magnification projection type, or an enlarged projection type. Although the transmissive reticle 18 is exemplified here, a reflective reticle 18 may be used. The projection optical system may be of a refraction type using transmission lenses, or of a reflection type using mirrors.

<Example>
Next, the present invention will be described in detail based on examples. As evaluation methods, the following (1) to (4) were used.

(1) Measurement of Refractive Index The prepared substrate holding plate 1 was measured by spectroscopic ellipsometry (trade name: EC-400, manufactured by JA Woollam), and the coating layer 51 and the coating layer at 365 nm (i-line wavelength). The refractive index of 52 was determined, and the refractive index ratio was calculated by dividing the refractive index of coating layer 51 by the refractive index of coating layer 52 .

(2) Evaluation of Reflectance The reflectance of the manufactured substrate holding plate 1 at a wavelength of 365 nm was measured with a spectrophotometer (CM-26d manufactured by Konica Minolta).

In addition, since the reflectance at a wavelength of 365 nm cannot be measured with a spectrophotometer, the average of the reflectances at a wavelength of 360 nm and the reflectance at a wavelength of 370 nm was taken as the reflectance at a wavelength of 365 nm.

(3) Evaluation of Peeling Resistance of Coating Layer 52 to Coating Layer 51 After wiping the substrate holding board 1 having the coating layer 52 formed thereon with Silbon paper, a spectrophotometer (CM-26d manufactured by Konica Minolta) was used. It was measured and evaluated according to the following criteria. The silbon paper was wiped off by reciprocating the silbon paper impregnated with ethanol 10 times with a load of 500 g/cm ² . The difference in reflectance before wiping and after wiping was evaluated.

(Example 1)
The substrate holding board 1 produced in Example 1 will be described with reference to FIG. A black alumina having a thickness of 60 mm was used for the base 2 of the substrate holding board 1 . The shape of the protrusion 3 was a truncated cone shape or a cylinder shape with a diameter of 0.8 mm and a height of 0.5 mm. Moreover, the pitch of the adjacent protrusions 3 was set to 20 mm. The coating layer 51 was formed by FCVA, and at least the surface of the protrusion 3 was coated with ta-C to a thickness of 500 nm. The ta-C deposition conditions by FCVA were a pressure of 0.03 Pa and an arc current of 35 A, and a carbon target was used as the target. The coating layer 52 was formed by plasma CVD, and aC:H was coated on at least the surface of the protrusion 3 to a thickness of 35 nm. The deposition conditions for the coating layer 52 by plasma CVD were an argon gas flow rate of 50 sccm, a toluene gas flow rate of 2.5 sccm, a pressure of 5 Pa, and an RF power of 300 W.

The results of Example 1 were as follows.
Refractive index ratio: 1.24
Difference between reflectance before wiping and reflectance after wiping: 0%

(Example 2)
It was produced in the same manner as in Example 1, except that the coating layer 52 was coated so as to have a thickness of 40 nm, and the pressure of the aC:H film formation conditions by plasma CVD was set to 1 Pa.

The results of Example 2 were as follows.
Refractive index ratio: 1.21
Difference between reflectance before wiping and reflectance after wiping: 0%

(Example 3)
It was produced in the same manner as in Example 1 except that the coating layer 52 was mainly composed of silicon carbide and was coated so as to have a thickness of 25 nm. The layer based on silicon carbide was produced by plasma CVD. The conditions for forming the coating layer 52 by plasma CVD are the same as those in the first embodiment.

The results of Example 3 were as follows.
Refractive index ratio: 1.48
Difference between reflectance before wiping and reflectance after wiping: 0%

(Example 4)
It was produced in the same manner as in Example 3 except that the coating layer 52 was coated so as to have a thickness of 65 nm.

The results of Example 4 were as follows.
Refractive index ratio: 1.48
Difference between reflectance before wiping and reflectance after wiping: 0%

(Example 5)
In order to make the coating layer 51 aC:H, it was coated by plasma CVD. It was coated so that the thickness of the coating layer 52 was 20 nm. Other than that, it was produced in the same manner as in Example 3. The deposition conditions for the coating layer 51 by plasma CVD were an argon gas flow rate of 50 sccm, a toluene gas flow rate of 2.5 sccm, a pressure of 5 Pa, and an RF power of 300 W.

The results of Example 5 were as follows.
Refractive index ratio: 1.20
Difference between reflectance before wiping and reflectance after wiping: 0%

(Example 6)
It was produced in the same manner as in Example 5 except that the coating layer 52 was coated so as to have a thickness of 70 nm.

The results of Example 6 were as follows.
Refractive index ratio: 1.20
Difference between reflectance before wiping and reflectance after wiping: 0%

(Comparative example 1)
It was produced in the same manner as in Example 5 except that the coating layer 52 was replaced with an inorganic particle film and the inorganic particle film was coated to a thickness of 60 nm. The inorganic particle film was formed by spray coating using an inorganic particle dispersion. The film formation conditions for the spray coating were a liquid supply amount of 7 g/min, a spray gun moving speed of 20 m/min, and an atomization pressure of 0.1 MPa. Also, the concentration of inorganic particles in the coating liquid was set to 0.4 wt %.

The results of Example 6 were as follows.
Refractive index ratio: 2.08
Difference between reflectance before wiping and reflectance after wiping: 10%

Table 1 shows the results for the substrate holding base 1 obtained in each example and comparative example.

(Evaluation of Examples and Comparative Examples)
In Examples 1 to 6, the difference between the reflectance of the coating layer 52 before wiping and the reflectance after wiping was 0%, and the substrate holding board 1 provided with the coating layer 52 having good peeling resistance was obtained. I was able to get

On the other hand, in Comparative Example 1, the material of the coating layer 52 was inorganic silica, and the material compatibility with the coating layer 51 was not favorable.

The coating layer 52 is mainly composed of a-C:H having a higher hydrogen content than the coating layer 51 or silicon carbide having a higher Si content than the coating layer 51, so that the coating layer 52 has peel resistance. was able to improve

It was shown that the substrate holding board 1 of the example is superior in peeling resistance of the coating layer 52 to the substrate holding board of the comparative example.

The embodiments described above can be modified as appropriate without departing from the technical concept. The disclosure of this specification includes not only what is described in this specification, but also all matters that can be grasped from this specification and the drawings attached to this specification.

It should be noted that the description e to f (where e and f are numerals) means e or more and/or f or less for the specific numerical ranges exemplified. Further, for the specific numerical ranges exemplified, when a range of i to j and a range of m to n are written together (i, j, m, and n are numbers)), the combination of the lower limit and the upper limit is It is not limited to i and j pairs or m and n pairs. For example, it may be considered to combine a plurality of sets of lower limits and upper limits. That is, when the range of i to j and the range of m to n are written together, the range of i to n may be examined as long as there is no contradiction, and the range of m to j may be examined. may be performed. Moreover, being equal to or greater than e means being e or greater than e (exceeding e), and a value greater than e may be adopted without adopting e. In addition, being equal to or smaller than f means f or smaller than f (less than f), and a value smaller than f may be employed instead of f.

The disclosure herein also includes complements of the individual concepts described herein. That is, for example, if there is a statement to the effect that "A is greater than B" in the present specification, even if the statement to the effect that "B is not greater than A" is omitted, the present specification states that "B is It can be said that it discloses that it is not larger than A. This is because the statement "A is greater than B" is based on the assumption that "B is not greater than A".

1 substrate holder 51 first layer 52 second layer H distance from the second layer to the top surface D thickness of the first layer

Claims (27)

A substrate holder having a first layer and a second layer interfacing with the first layer,
The first layer and the second layer are made of diamond-like carbon,
The refractive index of the first layer at a certain wavelength is higher than the refractive index of the second layer at the wavelength,
The substrate holding board, wherein the distance from the second layer to the top surface of the substrate holding board is smaller than the thickness of the first layer. 2. The substrate holder according to claim 1, wherein said second layer has a hydrogen content of 10 at % or more and less than 50 at %. 3. The substrate holder according to claim 1, wherein the second layer is aC:H. A substrate holder having a first layer and a second layer interfacing with the first layer,
The first layer is made of diamond-like carbon, the second layer is made of silicon carbide,
The refractive index of the first layer at a certain wavelength is higher than the refractive index of the second layer at the wavelength,
The substrate holding board, wherein the distance from the second layer to the top surface of the substrate holding board is smaller than the thickness of the first layer. 5. The substrate holder of claim 4, wherein the silicon content of the first layer is less than the silicon content of the second layer. 6. The substrate holder according to claim 1, wherein said first layer has a hydrogen content of less than 10 at %. 7. The substrate holder according to claim 1, wherein said first layer is ta-C. 5. The substrate holder according to claim 4, wherein said first layer has a hydrogen content of 10 at % or more and less than 50 at %. 9. The substrate holder according to claim 4, wherein said first layer is aC:H. 9. The substrate holding board according to any one of claims 1 to 8, wherein said top surface is formed by said second layer. 11. The substrate holding board according to any one of claims 1 to 10, wherein the distance H is smaller than the thickness of the second layer. 12. The substrate holder according to any one of claims 1 to 11, wherein the hydrogen content of said first layer is smaller than the hydrogen content of said second layer. At least one of the interface between the first layer and the second layer and the uppermost surface is a rough surface having an arithmetic mean roughness Ra of 0.4 μm or more and 4.0 μm or less. 13. The substrate holding board according to any one of 12. 14. The substrate holder according to any one of claims 1 to 13, wherein the second layer contains argon. 15. The substrate holding base according to any one of claims 1 to 14, wherein the refractive index of the first layer is 1.2 times or more the refractive index of the second layer. 16. The substrate holding board according to any one of claims 1 to 15, wherein said first layer has higher hardness than said second layer. 17. The substrate holding board according to any one of claims 1 to 16, wherein the thickness of the first layer is greater than the thickness of the second layer. 18. The substrate holding base according to any one of claims 1 to 17, wherein the first layer has a thickness of 500 nm or more and 10 [mu]m or less. 19. The substrate holder according to any one of claims 1 to 18, wherein the second layer has a thickness of 10 nm or more and less than 500 nm. Having a base that interfaces with the first layer, the base being provided on the opposite side to the second layer,
20. The substrate holding board according to any one of claims 1 to 19, further comprising a projection provided on the uppermost surface side with respect to the base. 21. The substrate holding plate of claim 20, wherein the base material is black alumina. 22. The substrate holder according to claim 1, wherein the wavelength is 300 nm or more and 400 nm or less. 23. A method of manufacturing a device, comprising placing a substrate on the substrate holding plate according to claim 1, and exposing the substrate. 24. The device manufacturing method of claim 23, wherein the substrate comprises a sapphire substrate. A substrate holding board according to any one of claims 1 to 22;
An exposure apparatus comprising: a light source; an optical system for irradiating a substrate with light emitted from the light source; and moving means for moving the substrate holding board. 26. An exposure apparatus according to claim 25, wherein said optical system includes a transmissive lens. 26. An exposure apparatus according to claim 25, wherein said optical system is of a reflective type including a mirror.

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