JP7532330B2 - Substrate holding plate, device manufacturing method, and exposure apparatus - Google Patents

Description

The present invention relates to a substrate holder.

In exposure devices, exposure processing is performed on substrates made of silicon, glass, SiC, etc. In these devices, the substrate mounting surface of the substrate holding plate wears over time due to use, and the reflectivity of the surface of the substrate holding plate increases, resulting in a problem in which the reflected light from the substrate holding plate irradiates areas that are not desired to be exposed. Therefore, Patent Document 1 proposes a configuration in which the 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 that order.

JP 2015-94002 A

The substrate holder in Patent Document 1 had a problem in that the adhesion between the DLC film and the inorganic coating agent was insufficient, and the inorganic transparent thin film was prone to peeling off.

Therefore, the present invention aims to provide a substrate holder that is highly resistant to peeling while suppressing the reflectance on the surface of the substrate holder.

The first means for solving the above problem is a substrate holder having a first layer and a second layer that forms an interface with the first layer, the first layer and the second layer contain 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 second layer is formed on the first layer.

A second means for solving the above problem is a substrate holder having a first layer and a second layer forming an interface with the first layer, wherein the first layer contains diamond-like carbon and the second layer contains 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 second layer is formed on the first layer.

The present invention provides a technology that is advantageous in improving the peel resistance of a substrate holding plate while suppressing the reflectance on the surface of the substrate holding plate.

FIG. 1A is a schematic diagram illustrating a substrate holding plate according to a first embodiment, FIG. 1B is an enlarged view of the area surrounded by circle 11, and FIG. 1C is an enlarged view of the area surrounded by circle 12 in FIG. 1A is a schematic diagram illustrating a substrate holding plate according to a second embodiment, FIG. 1B is an enlarged view of the area surrounded by circle 11, and FIG. 1C is an enlarged view of the area surrounded by circle 12 in FIG. 11A is a schematic diagram illustrating a substrate holding plate according to a third embodiment, and FIG. 11B is an enlarged view of a portion surrounded by a circle 13. FIG. A formula that describes the theoretical value of reflectance. FIG. 1 is a schematic diagram of an exposure apparatus according to an embodiment.

Below, a mode for carrying out the present invention will be described with reference to the drawings. However, the mode described below is one embodiment of the invention, and the present invention is not limited to this. In the following description and drawings, common symbols are used for configurations that are common across multiple drawings. The common configurations will be described with mutual reference to multiple drawings, and descriptions of configurations that are given common symbols will be omitted as appropriate.

Figure 1(a) shows a perspective view of a substrate holding disc of a first example according to this embodiment. The substrate holding disc 1 in this embodiment has a base 2 and a protrusion 3 on the base 2. One of the two main surfaces (front and back) of the substrate holding disc 1 (for convenience, referred to as the front) is the top surface 32, and a protrusion 3 is provided on the top surface 32 side relative to the base 2, but the protrusion 3 can be omitted. The top surface 32 is the surface on the side on which the substrate 7 is placed that comes into contact with the atmosphere surrounding the substrate holding disc 1, and is not necessarily the surface that comes into contact with the substrate 7. The top surface 32 can also function as a substrate holding surface for holding the substrate 7, for example.

Figure 1 (b) shows a perspective view of the substrate 7 placed on the substrate holding plate 1 of Figure 1 (a). The base 2 and the protrusions 3 provided on the base 2 hold the substrate 7. By supporting the substrate 7 with the protrusions 3, the contact area between the substrate holding plate 1 and the substrate 7 is reduced, and damage to the substrate 7 can be suppressed compared to when the protrusions 3 are not provided. The substrate 7 placed on the substrate holding plate 1 of the first example is a substrate 7 used in the manufacture of an electronic device. This substrate 7 can form part of an electronic device, but it may be removed during the manufacture of the electronic device and not form part of the electronic device. The substrate 7 can be, for example, a glass substrate, a resin substrate, or a sapphire substrate used in the manufacture of organic electroluminescence displays, liquid crystal displays, solar cell panels, etc.

In this example, the substrate holder 1 is provided with a suction hole 4, and the substrate 7 is vacuum-attached through the suction hole 4, but the suction hole 4 may be omitted.

Figure 1(c) shows a perspective view of a substrate holding plate of a second example according to this embodiment. Figure 1(d) shows a perspective view of a substrate 7 being placed on the substrate holding plate 1 of Figure 1(c). The substrate holding plate 1 of the second example differs from that of Figure 1(a) in that it has a circular outer shape, but otherwise has the same configuration. The substrate 7 placed on the substrate holding plate 1 of the second example can be, for example, a semiconductor substrate such as a Si wafer or a SiC wafer, or an insulating substrate such as a glass wafer, a plastic wafer, or sapphire.

The substrate holding plate 1 shown in Figures 1(a) to (d) can be used in various electronic device manufacturing equipment. For example, it can be used to hold a substrate 7 in an exposure device that exposes a photoresist applied to the substrate 7. It can also be used in film formation devices and etching devices, in addition to exposure devices.

As shown in FIG. 1(e), multiple substrate holders 1 can be arranged together to be used as a substrate holder 111.

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

Figure 2(a) is an enlarged cross-sectional view of the area surrounded by circle 10 in Figure 1(a) or Figure 1(c), Figure 2(b) is an enlarged view of the area surrounded by circle 11 in Figure 2(a), and Figure 2(c) is an enlarged view of the area surrounded by circle 12 in Figure 2(b).

The substrate holder 1 of this embodiment has a base 2 and a protrusion 3, as described in FIG. 1(a) or FIG. 1(c). The upper surface of the protrusion 3 has a coating layer 51 that forms an interface with the protrusion 3, and a coating layer 52 that has a lower refractive index and a higher hydrogen content than the coating layer 51, and both the coating layer 51 and the coating layer 52 are made of DLC (diamond-like carbon). DLC is a material that exhibits intermediate characteristics between diamond and graphite, which are mainly composed of carbon. Here, the top surface 32 is formed by a light coating layer 52 provided on the upper surface of the protrusion 3 and the upper surface of the base 2. The protrusion 3 can be omitted, and when the protrusion 3 is omitted, the coating layer 51 is provided on the upper surface of the base 2, and the coating layer 52 is provided on the upper surface of the coating 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 form an interface, respectively. In this embodiment, two layers, coating layer 51 and coating layer 52, are laminated, but as long as coating layer 51 and coating layer 52 are in close contact with each other, other layers may be provided above and below coating layers 51 and 52, making a total of three or more layers.

The base 2 will be described. The base 2 is composed of components 21, 22, and 23. Components 21, 22, and 23 are each made of the same material. Components 21, 22, and 23 made of at least a common material are called the base material, and the parts made of a common material are also called the base material. Components 21, 22, and 23 are located on the same plane. The lower surfaces of components 21, 22, and 23 are also located on the same plane, and form the back surface 24, which is the opposite side of the top surface 32. Component 22 is located between components 21 and 23. Covering layers 51 and 52 may be provided on components 21 and 23, and it is preferable that they are provided from the viewpoint of reducing reflectance.

The protrusion 3 will be described. The protrusion 3 exists on the component 22 of the base 2, and the protrusion 3 does not exist on the components 21 and 23, but a space is provided there. The protrusion 3 exists between the space above the component 21 and the space above the component 23, and a space exists between the two protrusions 3.

The protrusion 3 has a component 31 made of the same material as the base 2, and a coating layer 51 that forms an interface with the protrusion 3 and a coating layer 52 that forms an interface with the coating layer 51 are provided on the upper surface of the protrusion 3. The component 31 is also a base material.

Next, the coating layer 51 and the coating layer 52 will be described. In this embodiment, the coating layer 51 and the coating layer 52 are DLC, and by making the refractive index of the coating layer 52 lower than that of the coating layer 51, the coating layer 52 plays the role of an anti-reflection film and can reduce the reflectance. In addition, by stacking the coating layer 52 having a higher hydrogen content than the coating layer 51, the material compatibility of the coating layer 51 and the coating layer 52 is improved, and the peel resistance can be improved. From the viewpoint of improving the peel resistance, it is preferable that the coating layer 52 is directly above the air. In other words, the coating layer 52 is in contact with the atmosphere (e.g., air or inert gas) surrounding 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 protrusion 3 contacts and holds the substrate 7.

The coating layer 52 is located within a distance H from the top surface 32, and the distance H is smaller than the thickness D of the coating layer 51 (D>H). In other words, the coating layer 52 is located closer to the top surface 32 than the coating layer 51. In this embodiment, the coating layer 52 forms the top surface 32, so the distance H is 0.

For the coating layer 51, ta-C (tetrahedral amorphous carbon) or a-C:H (hydrogenated amorphous carbon) with a low hydrogen content is preferable among DLCs because it has a higher refractive index and a lower hydrogen content than the coating layer 52. For the coating layer 52, a-C:H is preferable among DLCs because it has a lower refractive index and a higher hydrogen content than the coating layer 51. The hydrogen concentration of ta-C is preferably less than 10 at%, more preferably less than 5 at%. The hydrogen concentration of a-C:H is preferably 10 at% or more and less than 50 at%, more preferably 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 higher the hydrogen concentration of DLC, the lower the hardness. Therefore, in this embodiment, coating layer 51 has a higher hardness than coating layer 52. The silicon content of coating layer 51 and coating layer 52 is equal, and is preferably 0 at%.

DLC can be defined by the ratio of sp2 hybrid orbitals to sp3 hybrid orbitals in the C-C bond and the hydrogen content, where the ratio of sp2 hybrid orbitals to sp3 hybrid orbitals is 0.1 to 1.9 for ta-C and 0.14 to 3.0 for a-C:H.

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 formed by PVD (Physical Vapor Deposition) such as arc ion plating. From the viewpoint of reducing droplets (particles with diameters of several tens of nanometers to several micrometers that can cause deterioration of the flatness of the film), FCVA (Filtered Cathodic Vacuum Arc) is more preferable among the arc ion plating methods.

a-C:H is deposited by a CVD method such as plasma CVD (Chemical Vapor Deposition). The hydrogen content and refractive index of DLC can be controlled by deposition conditions, such as the flow rate of the source gas and the substrate bias. The hydrogen content in DLC can be analyzed by Elastic Recoil Detection Analysis (ERDA). DLC may contain argon. The higher the argon content of DLC, the lower the refractive index of DLC, which is effective in suppressing reflection. The argon content of DLC may be less than 10 at%, and is preferably 1 at% or more. Note that at% refers to the content of an element and means atom% or atomic%. 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 to 3.0, more preferably 2.0 to 2.7. The refractive index of the coating layer 52 is preferably 1.3 to 2.5, more preferably 1.6 to 2.2, but is set to be 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 it is 10 μm or more, there is a high possibility of cracks occurring, so it is preferably less than 10 μm.

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

Here, we will explain the reflectance on the surface of the substrate holding plate. In exposure equipment that forms fine patterns, light rays with wavelengths of 365 nm (i-line), 405 nm (h-line), 436 nm (g-line), etc. are used. The theoretical value of the reflectance R on the surface of the substrate holding plate can be found from the four equations in Figure 5. The parameters of each equation are as follows:
R: reflectance _N3 : refractive index of air _N2 : complex refractive index of coating layer 52 for exposure wavelength λ _N1 : complex refractive index of coating layer 51 for exposure wavelength λ _NE : complex refractive index when coating layers 51 and 52 are regarded as one layer δ: phase difference π: circular constant d: thickness (nm) of coating layer 52
λ: exposure wavelength (nm)
i: imaginary unit

The complex refractive indexes N ₁ to N ₃ are refractive indices that take into account the absorption of light. The absorption of light is expressed by the extinction coefficient. For example, the complex refractive index of a refractive index of 1.7 and an extinction coefficient of 0.3 is 1.7-0.3i. This refractive index and extinction coefficient can be measured by an ellipsometry method or the like. From the four formulas in FIG. 3, it can be seen that if the extinction coefficients of the coating layer 52 and the coating layer 51 are equal, it is advantageous for the refractive index of the coating layer 51 to be greater than that of the coating layer 52 in terms of reducing reflection. From the viewpoint of reducing 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, and more preferably 2.0 times or less. By forming the coating layer 52 with a refractive index lower than that of the coating layer 51, the coating layer 52 can play the role of an anti-reflection film and can sufficiently reduce the reflectance.

The material constituting the substrate (base 2 and components 31) in this embodiment is black alumina. The thickness of the substrate (base 2 and components 31) is required to ensure the mechanical strength of the substrate holder 1, and is, for example, 10 to 100 mm, and preferably 60 mm or less. The thickness of the substrate (base 2 and components 31) may be 30 mm or less.

The material constituting the substrate is not limited to black alumina, but may be alumina, ceramics, zirconia, glass, plastic, metal, etc.

The shape and arrangement pitch of the protrusions 3 may be any shape that can support the substrate 7, and in this example, the protrusions are truncated cone-shaped or cylindrical-shaped. The pitch of the protrusions 3 is, for example, 1 mm or more and 100 mm or less, and preferably 10 mm or more and 30 mm or less. The pitch of the protrusions 3 may be 1 mm or more and 10 mm or less. The height of the protrusions 3 is, for example, 10 μm or more and 1 mm or less, and preferably 0.2 mm or more and 0.8 mm or less. The height of the protrusions 3 may be, for example, 50 μm or more and 0.5 mm or less, and may be 0.3 mm or less.

Next, the suction hole 4 according to this embodiment will be described. The suction hole 4 is connected at its lower opening to a vacuum pump (not shown) so that the air around the protrusion 3 can be sucked and reduced in pressure in order to hold the substrate 7 placed on the protrusion 3. By providing the protrusion 3, more air can be sucked in than when the protrusion 3 is not provided. In this example, the side of the suction hole 4 is coated with a coating layer 51, but since it is not the surface facing the substrate 7, it does not need to be coated with the coating layer 51. Similarly, the coating layer 51 does not need to be coated on the back surface 24 of the base 2 or the side surface 240 of the base 2.

Second Embodiment
A second embodiment will be described with reference to Fig. 3. This embodiment is different from the first embodiment in that the top surface 32 is formed of a coating layer 53.

Figure 3(a) is an enlarged cross-sectional view of the area surrounded by circle 10 in Figure 1(a) or Figure 1(c), Figure 3(b) is an enlarged view of the area surrounded by circle 11 in Figure 3(a), and Figure 3(c) is an enlarged view of the area surrounded by circle 12 in Figure 3(b).

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

In this embodiment, the upper surface of the protrusion 3 has a coating layer 53, and the upper surface of the base 2 has only coating layers 51 and 52, but the upper surface of the base 2 may have a coating layer 53. Also, the uppermost surface 32 on the upper surface of the protrusion 3 is a coating layer 53, while the uppermost surface 32 on the upper surface of the base 2 is a coating layer 52.

It is preferable that the coating layer 53 has a lower refractive index than the coating layer 52. This makes it possible to reduce the reflectance on the surface of the substrate holder 1 compared to the first embodiment.

Third Embodiment
The third embodiment will be described with reference to Fig. 4. This embodiment differs from the first embodiment in that it does not have the protrusion 3 and the top surface 32 is a rough surface.

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

By roughening the top surface 32, it is possible to reduce the reflectance on the surface of the substrate holder 1 during exposure processing. This reduces fluctuations in irradiation intensity and suppresses uneven exposure.

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. Furthermore, when the coating layer 53 is provided, the interface between the coating layer 52 and the coating layer 53 can also be roughened, and it is most preferable that the top surface 32 is rough, but it is sufficient that any one surface is rough. When the protrusion 3 is provided, it is preferable that not only the top surface of the protrusion 3 but also the upper surface of the base 2 is rough. This can improve the adhesion between the base 2 and the coating layer 51, and between the coating layer 51 and the coating layer 52.

Another benefit is that the contact area with the substrate 7 is smaller than when the top surface 32 is not rough, which reduces damage to the substrate 7.

Even when the top surface 32 is rough, the coating layer 52 is within a distance H from the top surface 32, which is smaller than the thickness D of the coating layer 51. The entire top surface 32 does not necessarily need to satisfy D>H, as long as at least a portion of it satisfies D>H. In this embodiment, the coating layer 52 forms the top surface 32, so the distance H is 0.

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

In this embodiment, as in the second embodiment, it is also possible to provide a coating layer 53 as the top surface 32.

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

In addition, in this embodiment, when coating layer 51 is ta-C, the hydrogen content is greater in coating layer 52 than in coating layer 51.

In this embodiment, the coating layer 51 only needs to have a higher refractive index than the coating layer 52, and may be made of diamond-like carbon such as ta-C or a-C:H. The silicon content of the coating layer 51 is 5 percent or less, and may be 0%.

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

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

Figure 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 that constitute an illumination optical system. The optical equipment EQP also includes a reticle stage 19 that supports a reticle 18, which is a pattern forming means, a projection optical system 25 that projects a pattern formed on the reticle 18, and a substrate holding plate 1 that supports a 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 collected by the projection optical system 25 and projected onto the substrate 7. The substrate 7 and the substrate holding plate 1 are moved by a substrate moving means 26, and the pattern formed on the reticle 18 by the light source 14 is projected onto the substrate 7. The substrate 7 is coated with a photoresist, and the photoresist is exposed by the exposure light 15. The substrate 7 may be a semiconductor wafer or a glass substrate for an FPD (flat panel display). The exposure light of the exposure apparatus is typically ultraviolet light. The wavelength of the exposure light is 436 nm for a g-line light source and approximately 365 nm for an i-line light source. It is approximately 248 nm for a KrF excimer laser light source, approximately 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 a reduced projection type, an equal magnification projection type, or an enlarged projection type. Although a transmissive reticle 18 is exemplified here, a reflective reticle 18 may also be used. The projection optical system may be a refractive type using a transmissive lens, or a reflective type using a mirror.

<Example>
The present invention will now be described in detail with reference to examples. The following evaluation methods (1) to (4) were used.

(1) Measurement of refractive index The prepared substrate holder 1 was measured by spectroscopic ellipsometry (product name: EC-400, manufactured by J.A. Woollam Corporation) to determine the refractive indexes of coating layers 51 and 52 at 365 nm (i-line wavelength). A 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 prepared substrate holding plate 1 at a wavelength of 365 nm was measured using a spectrophotometer (CM-26d manufactured by Konica Minolta).

Since the reflectance at a wavelength of 365 nm cannot be measured using a spectrophotometer, the average of the reflectance at wavelengths of 360 nm and 370 nm was used as the reflectance at a wavelength of 365 nm.

(3) Evaluation of peel resistance of coating layer 52 to coating layer 51 After wiping the substrate holding plate 1 on which coating layer 52 was formed with Silbon paper, it was measured with a spectrophotometer (CM-26d manufactured by Konica Minolta) and evaluated according to the following criteria. The wiping with Silbon paper was performed by moving Silbon paper soaked in ethanol back and forth 10 times with a load of 500 g/ ^cm2 . The difference in reflectance before and after wiping was evaluated.

Example 1
The substrate holder 1 produced in Example 1 will be described with reference to FIG. 2. The base 2 of the substrate holder 1 was made of black alumina with a thickness of 60 mm. The shape of the protrusions 3 was a truncated cone or cylinder with a diameter of 0.8 mm and a height of 0.5 mm. The pitch between adjacent protrusions 3 was 20 mm. The coating layer 51 was formed by FCVA, and ta-C was coated to a thickness of 500 nm on at least the surface of the protrusions 3. The conditions for forming the ta-C 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 a-C:H was coated to a thickness of 35 nm on at least the surface of the protrusions 3. The conditions for forming 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 in reflectance before and after wiping: 0%

Example 2
The coating was performed so that the thickness of the covering layer 52 was 40 nm, and the pressure of the aC:H film formation conditions by plasma CVD was set to 1 Pa. The manufacturing process was the same as in Example 1.

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

Example 3
The coating layer 52 was mainly composed of silicon carbide, and was produced in the same manner as in Example 1, except that the coating layer 52 was coated to a thickness of 25 nm. The layer mainly composed of silicon carbide was produced by plasma CVD. The deposition conditions for the coating layer 52 by plasma CVD were the same as in Example 1.

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

Example 4
The fabrication was carried out in the same manner as in Example 3, except that the coating was carried out so that the thickness of the covering layer 52 was 65 nm.

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

Example 5
Coating was performed by plasma CVD to make coating layer 51 a-C:H. Coating was performed so that coating layer 52 had a thickness of 20 nm. Other than that, it was produced in the same manner as in Example 3. The film formation conditions for 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 in reflectance before and after wiping: 0%

Example 6
The fabrication was carried out in the same manner as in Example 5, except that the coating was carried out so that the thickness of the covering layer 52 was 70 nm.

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

(Comparative Example 1)
The coating layer 52 was replaced with an inorganic particle film, and the inorganic particle film was coated to a thickness of 60 nm, but the coating was performed in the same manner as in Example 5. The inorganic particle film was formed by spray coating using an inorganic particle dispersion. The film forming conditions of the spray coating were a liquid supply rate of 7 g/min, a spray gun moving speed of 20 m/min, and an atomization pressure of 0.1 MPa. The inorganic particle concentration of the coating liquid was 0.4 wt%.

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

The results for the substrate holding discs 1 obtained in each of the Examples and Comparative Examples are shown in Table 1.

(Evaluation of Examples and Comparative Examples)
In Examples 1 to 6, the difference in reflectance of coating layer 52 before and after wiping was 0%, meaning that a substrate holding disc 1 having coating layer 52 with good peel resistance was obtained.

In contrast, in Comparative Example 1, the material of coating layer 52 was inorganic silica, which was not compatible with coating layer 51, and the film peeled off when wiped, resulting in a 10% increase in reflectance.

By making coating layer 52 a layer mainly composed of a-C:H, which has a higher hydrogen content than coating layer 51, or silicon carbide, which has a higher Si content than coating layer 51, the peeling resistance of coating layer 52 can be improved.

The substrate holder 1 of the embodiment was shown to have superior peel resistance of the coating layer 52 compared to the substrate holder of the comparative example.

The above-described embodiments 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 understood from this specification and the drawings attached hereto.

In the specific numerical ranges given as examples, the description e to f (e and f are numbers) means e or more and/or f or less. In addition, when the ranges i to j and m to n are both given as examples of specific numerical ranges (i, j, m, and n are numbers), the combination of the lower limit and the upper limit is not limited to the combination of i and j or the combination of m and n. For example, the combination of the lower limit and the upper limit of multiple combinations may be considered. In other words, when the ranges i to j and m to n are both given, the range i to n may be considered, or the range m to j may be considered, as long as no contradiction occurs. In addition, being e or more means e or larger than e (exceeding e), and a value larger than e may be adopted without adopting e. In addition, being f or less means f or smaller than f (less than f), and a value smaller than f may be adopted without adopting f.

Furthermore, the disclosure of this specification includes the complement of the individual concepts described in this specification. In other words, if this specification contains a statement that "A is greater than B," for example, even if the statement that "B is not greater than A" is omitted, this specification can be said to disclose that "B is not greater than A." This is because when it states that "A is greater than B," it is assumed that the case in which "B is not greater than A" is taken into consideration.

1: Substrate holder 51: First layer 52: Second layer H: Distance from second layer to top surface D: Thickness of first layer

Claims (33)

A substrate holder having a first layer and a second layer interfacing with the first layer,
the first layer and the second layer contain diamond-like carbon;
a refractive index of the first layer at a certain wavelength is higher than a refractive index of the second layer at the certain wavelength;
The second layer is formed on the first layer. The substrate holder of claim 1, characterized in that the second layer has a hydrogen content of 10 at% or more and less than 50 at%. The substrate holder according to claim 1 or 2, characterized in that the second layer is a-C:H. A substrate holder having a first layer and a second layer interfacing with the first layer,
the first layer includes diamond-like carbon and the second layer includes silicon carbide;
a refractive index of the first layer at a certain wavelength is higher than a refractive index of the second layer at the certain wavelength;
The second layer is formed on the first layer. The substrate holder of claim 4, characterized in that the silicon content of the first layer is less than the silicon content of the second layer. The substrate holder according to any one of claims 1 to 5, characterized in that the first layer has a hydrogen content of less than 10 at%. The substrate holder according to any one of claims 1 to 6, characterized in that the first layer is ta-C. The substrate holder according to claim 4, characterized in that the first layer has a hydrogen content of 10 at% or more and less than 50 at%. The substrate holder according to claim 4 or 8, characterized in that the first layer is a-C:H. A substrate holder having a first layer and a second layer interfacing with the first layer,
the first layer contains diamond-like carbon having a hydrogen content of less than 10 at %,
the second layer contains diamond-like carbon having a hydrogen content of 10 at % or more and less than 50 at %,
The second layer is formed on the first layer. The substrate holder according to any one of claims 1 to 8, characterized in that the top surface of the substrate holder is formed by the second layer. The substrate holder according to any one of claims 1 to 11, characterized in that the second layer has a reflectance of 10% or less. The substrate holder according to any one of claims 1 to 12, characterized in that the distance from the second layer to the top surface of the substrate holder is less than the thickness of the first layer. The substrate holder according to any one of claims 1 to 13, characterized in that the hydrogen content of the first layer is smaller than the hydrogen content of the second layer. A substrate holder having a substrate,
a first layer made of a material containing diamond-like carbon and provided at least on the uppermost surface side of the substrate;
a second layer provided directly on the first layer and made of a material containing diamond-like carbon having a higher nitrogen content than the first layer;
A substrate holder, wherein the second layer has a thickness of 5 nm or more and 200 nm or less. The substrate holder of claim 15, characterized in that the thickness of the second layer is 5 nm or more and 30 nm or less. The substrate holder according to claim 15 or 16, characterized in that the first layer has a portion having a nitrogen content of 1 at% or less, and the second layer has a portion having a nitrogen content of more than 1 at%. The substrate holder according to claim 17, characterized in that the second layer has a portion having a nitrogen content of 3 at% or more. The substrate holder according to any one of claims 15 to 18, characterized in that the nitrogen content of the second layer decreases from the side of the second layer opposite the first layer toward the first layer side. A substrate holder having a substrate,
a first layer made of a material containing diamond-like carbon and provided at least on the uppermost surface side of the substrate;
a second layer provided directly on the first layer and made of a material containing diamond-like carbon having a higher nitrogen content than the first layer;
A substrate holder, characterized in that the nitrogen content of the second layer decreases from the side of the second layer opposite the first layer toward the first layer. The substrate holder according to claim 19 or 20, characterized in that the second layer has a portion with a nitrogen content of 5 at% or more and 30 at% or less, and a portion with a nitrogen content of 3% or less. The substrate holder according to any one of claims 15 to 21, characterized in that a third layer is provided on the side of the second layer opposite to the side of the first layer, and the refractive index of the third layer is lower than the refractive index of the second layer. The substrate holder according to claim 22, characterized in that the top surface of the substrate holder is formed by the third layer. The substrate holder according to any one of claims 1 to 23, characterized in that at least one of the interface between the first layer and the second layer and the top surface is a rough surface having an arithmetic mean roughness Ra of 0.4 μm or more and 4.0 μm or less. The substrate holder of any one of claims 1 to 24, characterized in that the thickness of the first layer is greater than the thickness of the second layer. A substrate holder having a first layer and a second layer formed directly on the first layer,
The first layer and the second layer contain diamond-like carbon having hydrogen or nitrogen, and the hydrogen content of the first layer is smaller than the hydrogen content of the second layer, or the nitrogen content of the first layer is smaller than the nitrogen content of the second layer. A method for manufacturing a device, comprising placing a substrate on a substrate holder according to any one of claims 1 to 26 and exposing the substrate. The method for manufacturing a device according to claim 27, characterized in that the substrate includes a sapphire substrate. A method for manufacturing a substrate holder according to any one of claims 15 to 26, comprising the steps of:
A manufacturing method comprising the steps of: implanting nitrogen ions into a layer made of a material containing diamond-like carbon to form the second layer. The manufacturing method described in claim 29, characterized in that the nitrogen ions are implanted by a plasma ion implantation method. A substrate holder according to any one of claims 1 to 26,
An exposure apparatus comprising: a light source; an optical system for irradiating a substrate with light emitted from the light source; and a moving means for moving the substrate holding plate. The exposure apparatus according to claim 31, characterized in that the optical system includes a transmissive lens. The exposure apparatus according to claim 31, characterized in that the optical system is a reflective type including a mirror.

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