JP2006210546A - Substrate holding board for exposure process and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate holding board for exposure process for returning reflectivity to that of the material, where such reflectivity has been raised by the process even if reflectivity of a material itself is lower when a ceramics material is used as the low reflectivity material. <P>SOLUTION: In the substrate holding board for exposure process, at least a substrate holding side surface is formed of a ceramics material, saturation index b* is positive at the surface of the substrate holding side, luminosity index L* is 70 or less, and surface roughness Ra is 0.6 μm or less. In the preferable profile of the same substrate holding board for exposure process, the total reflectivity in the range of the optical wavelength of 250 to 550 nm at the surface of substrate holding side is 13% or less. Moreover, the saturation index b* at the surface of substrate holding side is positive, and a main element of ceramics is silicon carbide or alumina. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an exposure processing substrate holder such as an exposure apparatus for manufacturing a semiconductor element or a liquid crystal display, and in particular, the accuracy of exposure, alignment, or focus adjustment is achieved by reflection of illumination light transmitted through the exposure processing substrate such as a wafer. The present invention relates to a substrate holder for exposure processing that is not damaged.

  Conventionally, characteristics required for ceramic materials include thermal characteristics such as heat resistance, mechanical characteristics such as strength, scientific characteristics such as corrosion resistance, and electromagnetic characteristics such as conductivity. In recent years, ceramics having optical characteristics with low saturation such as black have been required for electronic parts, parts for semiconductor manufacturing equipment, various measuring devices, and the like. This is because even a small amount of dust greatly affects the accuracy and characteristics of these parts, so in the case of a low-saturation material such as black, the presence of these dusts can be quickly found, and the parts wear out. It is because it is easy to identify the part when it is damaged.

In addition to this, in recent years, in such fields, there are many devices for the purpose of exposing or measuring light such as laser, ultraviolet light and visible light, and members used in such devices are used for reflection of unwanted light (irregular reflection). In many cases, a material that does not reflect or transmit light is required.
For substrate holders for exposure processing, such as wafer chucks for exposure devices for manufacturing semiconductor elements and liquid crystal displays, we have used alumite-plated base materials made of alumina metals, stainless steel and anodized ceramics. The base material to be coated with TiC or the like was used. A substrate such as a wafer (hereinafter sometimes simply referred to as a “substrate”) is held on such a substrate holding plate, and is one of the illumination light irradiated with illumination light for exposure or illumination light for alignment or focus adjustment. The portion passes through the substrate and reaches the substrate holding plate, and a part of the portion is reflected by the surface of the substrate holding plate, which is one of the causes of a decrease in exposure accuracy.

For example, in a substrate holder of an exposure apparatus for manufacturing a semiconductor element or a liquid crystal display, a base material made of an aluminum-based metal is subjected to alumite treatment, a SiC sintered body, HIP (Hot Isostatic Pressing), heat Interstitial hydrostatic compression method) Uses a black ceramic material with relatively little light reflection, such as a treated alumina sintered body or a HIP treated TiC sintered body, or a surface processed rough in order to diffusely reflect light The example using this is proposed (refer patent document 1, patent document 2, patent document 3, and patent document 4).
Japanese Patent Laid-Open No. 5-205997 JP-A-5-254922 JP-A-8-12416 JP 9-45753 A

  However, the demand for higher performance has become more severe, and it has become impossible to obtain a sufficiently low reflectance even when the above-described method is used. Also, even if the reflectivity of the sample material is sufficiently low, the low reflectivity measured with the sample cannot be realized on the surface processed for use as a substrate holder for exposure processing. Therefore, a part of the illumination light incident on the glass substrate, which is a plate-like transparent object to be processed such as an exposure apparatus for liquid crystal glass, is reflected by the surface of the substrate holder for exposure processing, and again returns to a specific portion of the substrate. Incidence occurs, and unnecessary portions of the resist are exposed, and problems such as a decrease in the accuracy of alignment and focus adjustment occur.

  In order to solve the above-mentioned problems, the present inventors have made extensive studies and, when a low-reflectance ceramic is used for the substrate holder for exposure processing, even if the low-reflectance ceramic is a surface finish, The inventors have found that the reflectance changes depending on the state, and have completed the present invention.

  An object of the present invention is to provide an exposure processing substrate holder that does not impair the accuracy of exposure, alignment, or focus adjustment due to the reflection of illumination light that has passed through an exposure processing substrate such as a wafer.

  In the substrate holder for exposure processing of the present invention, at least the substrate holding side surface is made of ceramics, the saturation index b * of the substrate holding side surface is positive, the lightness index L * is 70 or less, and the surface roughness. Ra is a substrate holder for exposure processing, characterized in that it is 0.6 μm or less.

The substrate holder for exposure processing of the present invention includes the following preferred modes.
(a) The total reflectance in the light wavelength range of 250 to 550 nm on the substrate holding side surface is 13% or less.
(b) The crystal grain size of the ceramic constituting the substrate holding side surface is 3 μm or more.
(c) The ceramic component is silicon carbide or alumina.
(d) The substrate holder for exposure processing is at least one selected from the group consisting of Fe ₂ O ₃ , Mn ₂ O ₃ , Cr ₂ O ₃ , CoO, TiO ₂ , CuO, NiO, TiC, SiC and C. Containing one additive.
(e) The substrate placed on the substrate holding plate is a substrate irradiated with illumination light.
In addition, in the method for manufacturing a substrate holder for exposure processing according to the present invention, at least the surface on the substrate holding side is processed after processing the substrate holding pattern on a base material made of ceramics having a positive chroma index b *. A method of manufacturing a substrate holder for exposure processing, wherein the surface is polished using loose abrasive grains.

  The substrate holder for exposure processing according to the present invention has low light reflectivity and excellent wear resistance as a substrate holder that is used repeatedly, and has a low density and high Young's modulus. It has excellent characteristics such that it does not easily cause distortion due to the substrate and does not reduce the processing accuracy of the substrate, and is useful as a precision member for electronic parts, parts for semiconductor manufacturing equipment, parts for liquid crystal manufacturing equipment, various measuring devices and the like.

Hereinafter, the substrate holder for exposure processing of the present invention will be specifically described in detail.
The substrate holder for exposure processing of the present invention is a holder used to hold an exposure processing substrate, which is a thin flat object to be processed, such as a semiconductor element or a glass plate for a liquid crystal display, in a processing apparatus. Say the board. The surface roughness Ra is an arithmetic average roughness defined by JIS B0601 (2001).
In the substrate holder for exposure processing of the present invention, at least the surface on the substrate holding side is composed of a base material made of ceramics.

  It is essential that the substrate holding disk using the low-reflectance ceramic used in the present invention has a surface roughness Ra of 0.6 μm or less. Until now, it was generally said that the reflectivity of a material is lower as the surface roughness is higher. However, when viewed with the human eye, this is a mirror-like surface that has a high reflectivity. This is because I feel that. However, the reflectance that is a problem in the present invention is not only the regular reflection but also the total reflection amount including all irregularly reflected light that is difficult to be felt by the human eye, and is slightly different from the reflectance that can be felt by the human eye. Is. In particular, on a surface with a rough surface roughness, the reflectance is low because the regular reflection is small and the diffuse reflection amount is large, but the light reflection amount of a material is basically close to the refractive index of the light of the material. There is a relationship and is a numerical value specific to the material. As described above, the surface roughness only changes the balance between the regular reflection amount and the irregular reflection amount, and the total reflection amount does not change.

However, as a result of a detailed examination of the amount of light reflected by this ceramic material, it was discovered that the total reflection amount is closely related to the surface roughness.
The total reflectivity is settled to reflect a material specific as the surface roughness is small, and the total reflectivity is increased as the surface roughness is increased. This is closely related to the processing performed to generate the surface of the surface having a rough surface. In the case of a ceramic material, processing is generally performed using a grindstone or free abrasive grains using hard abrasive grains such as diamond, alumina, or silicon carbide. At this time, it is known that the surface roughness becomes coarser as the abrasive grains having a larger particle diameter are used, and the surface roughness can be further reduced by using smaller abrasive grains. At this time, in order to destroy the surface of the material generated with large abrasive grains with a large processing force, it is known that there is a work-affected layer such as a microcrack near the material surface in the case of ceramic materials. Yes.

  This work-affected layer is so deep that large abrasive grains are used, and large defects are generated. If there is a defect in the ceramic material, it is divided into light reflected by the surface of the material and transmitted light incident on the inside when irradiated with light. Light incident on the inside of the ceramic material travels through the inside of the ceramic crystal while being attenuated and hits the grain boundary. At this time, light is divided into reflection and transmission here due to the anisotropy of the grain boundary. There is also light that is reflected repeatedly and emerges as reflected light from within the material. When there is no defect, the reflectivity is specific to the material. However, when a defect exists in the crystal, light is reflected and transmitted again, resulting in an increase in reflected light. For this reason, it is assumed that the reflectivity of a material with many defects is increased.

In order to achieve this reflectivity, it is necessary that the surface roughness Ra is 0.6 μm or less in terms of the arithmetic average roughness of the surface roughness, considering the amount and size of the above-mentioned defects with a material with low reflectivity. There is. The surface roughness Ra is desirably 0.5 μm or less, and more desirably, the surface roughness Ra is 0.4 μm or less.
As a method of relaxing or removing the work-affected layer and material defects on the material surface, a method of aging again for 10 hours to 100 hours in the temperature range near the sintering temperature, or a process-affected layer is difficult to form # A method of processing with 600 or more grindstones, a method of lapping with free and grain using a platen such as casting, copper, tin, etc., if a pattern is formed, using a free abrasive grain with a cloth or brush For example, a buffing method may be used.

  For the amount of light reflection, a method using the total reflectance defined in JIS K 7105 can be employed. In the field of applying a ceramic material (sintered body) as in the present invention, it is an application that dislikes reflection of all light including irregular reflection, and it is most suitable to evaluate using total reflectance. The total reflectance is measured by combining a regular reflection component and a diffuse reflection component using a spherical integrating sphere, and is measured according to JIS K 7105 here.

Usually, a member used in an apparatus that uses laser light or ultraviolet light, and a member that requires low reflectance, a black chrome-plated product or a black anodized product is used. The total reflectance of these processed products is 5 to 7% at a light wavelength of 200 to 950 nm in a black chrome plated product, and 6 to 8% at a light wavelength of 200 to 650 nm in a black anodized product. It becomes 10 to 60% at 700 to 950 nm. The lower the total reflectivity, the better the light reflection can be prevented. However, in general, when the total reflectivity is 13% or less in the light wavelength range of 200 to 550 nm, the reflection of the light is disliked. It can also be used practically without problems in the members of the apparatus. More preferable results can be obtained if the total reflectance is 11% or less. In an apparatus that exposes glass having a particularly high transparency such as liquid crystal, the total reflectance is particularly required to be low, and the total reflectance is preferably 10% or less as a material used in this field. In order to obtain a preferable total reflectance, it can be achieved by controlling the sintering atmosphere and adding an additive as shown below.
It is important that the saturation index b * of the substrate holding side surface of the substrate holder for exposure processing of the present invention is positive. When the saturation index b * is zero or less, the reflectance at a short wavelength of 550 nm or less increases. Therefore, the saturation index b * is preferably in the range of more than 0 and 30 or less. If the saturation index b * exceeds 30, the reflectivity tends to be high at all wavelengths, which may increase the reflectivity.

  In addition, the substrate holder for exposure processing of the present invention requires that the lightness index L * of the substrate holding side surface be 70 or less. If the lightness index L * exceeds 70, it is excessively bright and the reflectance becomes high, which is not preferable. The lightness index L * is preferably 60 or less.

The saturation index b * is a value obtained by a measurement method standardized by the International Commission on Illumination (CIE 1976 (L * a * b *)). In Japanese Industrial Standards, it corresponds to JIS Z 8729 (1980). Here, L * represents lightness, and a * and b * represent saturation, each having the following meaning.
a * = + 60, b * = 0: Pure red a * = − 60, b * = 0: Pure green a * = 0, b * = + 60: Pure yellow a * = 0, b * = − 60: Pure blue L * max = 100, a * = 0, b * = 0: Pure white L * max = 0, a * = 0, b * = 0: Pure black The ceramics whose brightness and saturation are adjusted in this way are, for example, It can be obtained by firing silicon carbide, aluminum nitride, alumina titanium carbide, etc. in a non-oxidizing atmosphere such as argon, helium, nitrogen, vacuum, etc., and in the case of oxides such as aluminum oxide and zirconium oxide, It can be obtained by adding an inorganic additive for lowering the saturation.

Preferable examples of inorganic substances used for adjusting the brightness and saturation include Fe ₂ O ₃ , Mn ₂ O ₃ , Cr ₂ O ₃ , CoO, TiO ₂ , CuO, NiO, TiC, SiC, and C. It is done. In particular, in order to make the saturation index b * positive, Fe ₂ O ₃ , Mn ₂ O ₃ , Cr ₂ O ₃ , TiC, SiC and C are preferably used.

  Here, as a method for measuring the presence of an inorganic substance other than alumina, for example, a known method such as inductively coupled plasma atomic emission (Inductive Coupled Plasma Atomic Emission) can be used.

  In the present invention, the average crystal particle diameter of the ceramic (alumina sintered body) is preferably 3 μm or more. The average crystal particle diameter is more preferably 3 μm or more and 20 μm or less. This is because it is effective to keep the crystal grain size above a certain level in order to reduce grain boundaries and reduce the presence of pores. To increase the average crystal grain size, for example, it is possible to increase the sintering temperature, but it is also possible to increase the average crystal grain size with an additive that promotes the grain growth of alumina such as Si and Ti. It is. However, since the mechanical properties such as strength are lowered when the average crystal grain size is too larger than 20 μm, it is desirable to control the average crystal grain size by the pinning effect of spinel with Mg or the like. A method for measuring the average crystal grain size will be described later.

  In the present invention, if at least the surface on the substrate holding plate side is made of a low-reflectance ceramic, the performance as a substrate holding plate for exposure processing can be satisfied. There is no particular limitation on the base material when only the surface is made of ceramic, but the ceramic part is sprayed on the surface of a relatively light and rigid metal such as an aluminum alloy or magnesium alloy, or a thin plate-like ceramic surface. Can be fixed by bonding or screwing. In addition, when metal is used as a base material, a low thermal expansion metal called Invar is used when the flatness of the substrate holding plate is distorted due to the bimetallic effect of ceramics and metals with different linear expansion coefficients due to temperature rise due to heat generated by the machine. It is desirable to use Further, although the surface is required to be a ceramic having a low reflectance, it may be a ceramic having higher rigidity than alumina such as silicon carbide or silicon nitride in order to increase the rigidity of the substrate holder.

When a material using the above-described material is used as a substrate holding plate, static electricity or vacuum is used to fix the substrate on the substrate holding plate. In any case, if the contact area is large when removing the substrate, it will take time to reduce the adsorption force. Therefore, the contact area is as small as possible, and especially in the case of vacuum, Since the substrate may be distorted, the shorter the length of the portion not holding the substrate is better. In order to make this compatible, it is desirable to arrange the substrate holding portions having the smallest possible area at a small pitch.
In the present invention, a substrate holding pattern is obtained by processing a substrate holding pattern on a base material made of ceramics at least on the substrate holding side, and then polishing the processed surface using loose abrasive grains. Can do.
The pattern processing of the substrate holding portion is not particularly limited, but a groove may be formed with a fine-shaft grindstone, or a method of processing a substrate holding disc masked in a pattern shape by sandblasting or the like There is.

  When these pattern processings are performed, the above-mentioned work-affected layer always exists in the case of a ceramic material. In order to remove only the process-affected layer on the surface without damaging the pattern, loose abrasives were used to fabricate felt, non-woven fabrics, fabrics such as woven fabrics and knitted fabrics, and rubber and urethane resins and wood chips. It is possible to buff with a soft material such as a wheel, pad or brush. When using free abrasive grains for polishing, it is not particularly limited, but for example, it can be carried out by the following method.

  As the free abrasive grains, generally available abrasive grains such as diamond, alumina, silicon carbide and the like can be used. In order to increase the efficiency of the polishing process, use a diamond of about 10 to 50 μm, which has high hardness and good processing efficiency at the beginning of the process, and gradually reduces the grain size of the free abrasive grains. And finished with abrasive grains of 10 μm or less. In addition, in order to finish the surface with a less work-affected layer, although the processing efficiency is inferior, particles such as alumina, silicon carbide, silica, and ceria that have a small difference in hardness from the non-processed material can be used.

  The substrate holder for exposure processing according to the present invention can be suitably used for manufacturing TFTs for display such as liquid crystal and EL, color filters, and exposure for manufacturing a CPU on a glass substrate used in a thin computer. I can do it.

  Hereinafter, the substrate holder for exposure processing of the present invention will be described based on examples. In addition, the measurement and evaluation of the physical property of an Example were performed as follows.

(1) Measurement of surface roughness Ra The powder was molded under the condition of 1 ton / cm ² using a cold isostatic press (Cold Isostatic Press), the molded body was processed into a cylinder of φ25 × L25 mm, and sintered. did. The obtained sintered body was cut to a thickness of 5 mm, and the flat portion was cut with a # 200 grindstone at a depth of 0.02 mm and 0.3 mm from the sintered surface, and then # 200 alumina by sandblasting. What was roughened with abrasive grains was buffed with diamond abrasive grains and used as a sample. For the surface roughness, the arithmetic average roughness of JIS B0601 (2001) was measured using a surface roughness measuring device SURFCOM 1400D manufactured by Tokyo Seimitsu. In the measurement, an arbitrary position of the sample was measured five times, and the average value was defined as the surface roughness. The purpose of this measurement is not to reduce the unevenness created by the roughing process, but to remove the surface layer. Therefore, if the local unevenness created by the roughing process can be removed, the roughness curve will be global. However, it is not a problem to swell, so the measurement conditions were as follows. The measurement length was 0.4 mm, the cutoff was a wavelength of 0.08 mm, Gaussian was used, the measurement speed was 0.15 mm / second, and the least-squares linear correction was used to correct the inclination.

(2) Measuring surface roughness Ra of the total reflectance of the cylindrical sintered body using a Hitachi spectrophotometer U3210 type, changing the light wavelength from 250 nm to 550 nm, and the reflected light with an integrating sphere Collection measurement was performed, and the largest measured value in the range was defined as the reflectance.

(3) Measurement of average crystal grain size The flat part of the same sample used for the measurement of surface roughness was mirror finished and thermally etched at a temperature 50 ° C. lower than the sintered temperature for 3 hours. The sample was observed using a scanning electron microscope, and 2000-times photographs were taken at five arbitrary points. Using an image processing apparatus, the average equivalent circle diameter of the crystal grains of the photographed photograph was determined. The average equivalent circle diameter was determined for an area of 10 cm ² or more per photograph, and the average equivalent circle diameter of the five photographs was taken as the average crystal particle diameter.

(4) Saturation measurement and index b * and lightness index L * again
Both surfaces of a cylindrical sintered body having a thickness of 5 mm were ground with a surface grinder using a # 600 grindstone to obtain a measurement sample. As a measuring device, a color difference color measuring device CM-2002 manufactured by Minolta Co., Ltd. was used. In the measurement, a part of incident light was absorbed by the sample, and reflected and scattered afterglow was collected and detected by an integrating sphere. The light source uses a xenon lamp, and the light is measured with two spectroscopes installed on the integrating sphere, and the light with a wavelength of 400 to 700 nm is dispersed and calculated in units of 10 nm. M as the object color measured in (1), and its absolute value is obtained in the L * a * b * color system. In this measurement, measurement was performed in an SCI (Special Component Included) mode that detects all of the reflected scattered light, and a JIS standard white plate was used as a reference color. This measurement method is defined in JIS Z 8722 (1982) and JIS Z 8103 (measurement terms), 8105 (1982) (terms relating to color) 8120 (1986) (optical terms).

Example 1
Alpha alumina powder of 99.99% purity, 350 g of Fe ₂ O ₃ as an inorganic substance, 150 g of MnO, 30 kg of ion exchange water (solvent), 150 g of magnesium oxide, 50 g of a dispersant (ammonium polycarboxylate), 10 of polyvinyl alcohol as a binder A slurry was prepared by stirring and mixing 3000 g of a weight% solution and 200 g of polyethylene glycol # 400 as a plasticizer with a ball mill in a wet manner for 24 hours. This slurry was spray-dried with a spray dryer to produce granules having an average particle size of 60 μm. The granules were conditioned to a moisture content of 0.5% by weight and then subjected to rubber press molding with a molding pressure of 1.0 ton / cm ² to produce a cylindrical molded body having a diameter of 20 mm and a height of 10 mm. Next, the cylindrical molded body thus obtained was sintered in the atmosphere at a temperature of 1600 ° C. for 3 hours. This sintered body is processed to a diameter of 15 mm with a cylindrical grinder and to a height of 5 mm with a surface grinder, and this processed plane is further roughened by sandblasting with # 200 alumina particles. Went. The processed surface was processed with a cloth buff using 20 μm diamond powder until the surface was glossy. At this time, the saturation index b * was 3.5, and the lightness index L * was 39. The surface roughness Ra was 0.48 μm and the total reflectance was 11%. The results are shown in Table 1. When a transparent glass substrate coated with a resist film is placed on the surface of this test piece and the pattern is exposed, a pattern with a clean rectangular cross section can be formed without causing problems such as line breakage due to double exposure. I was able to.

(Example 2)
The sample prepared in Example 1 was further processed with a cloth buff using 6 μm diamond powder. The processed surface had a saturation index b * of 3.5, a brightness index L * of 32, a surface roughness Ra of 0.12 μm, and a total reflectance of 6.5%. The results are shown in Table 1. When a transparent glass substrate was placed on the surface of the test piece and the pattern was exposed, a pattern with a clean rectangular cross section could be formed without causing problems such as line breakage of the pattern due to double exposure.

(Comparative Example 1)
The sample prepared in Example 2 was again roughened by sandblasting with # 200 alumina particles. At this time, the saturation index b * was 3.5, the lightness index L * was 41, the surface roughness Ra was 1.02 μm, and the total reflectance was 15.5%. The results are shown in Table 1.

(Comparative Example 2)
Α alumina powder of 99.99% purity, 350 g of Fe ₂ O ₃ as inorganic material, 150 g of CoO, 30 kg of ion exchange water (solvent), 150 g of magnesium oxide, 50 g of dispersant (ammonium polycarboxylate), 10 of polyvinyl alcohol as a binder A slurry was prepared by mixing 3000 g of a weight% solution and 200 g of polyethylene glycol # 400 as a plasticizer with a ball mill for 24 hours by wet mixing. This slurry was spray-dried with a spray dryer to produce granules having an average particle size of 50 μm. The granules were conditioned to a moisture content of 0.5% by weight and then subjected to rubber press molding with a molding pressure of 1.0 ton / cm ² to produce a cylindrical molded body having a diameter of 20 mm and a height of 10 mm. Next, the cylindrical molded body thus obtained was sintered in the atmosphere at a temperature of 1600 ° C. for 3 hours. This sintered body is processed to a diameter of 15 mm with a cylindrical grinder and to a height of 5 mm with a surface grinder, and this processed plane is further roughened by sandblasting with # 200 alumina particles. Went. The processed surface was processed with a cloth buff using 20 μm diamond powder, and further finished with a 6 μm diamond powder. At this time, the saturation index b * was −4.2, the lightness index L * was 48, the surface roughness Ra was 0.32 μm, and the total reflectance was 17.8%. The results are shown in Table 1.

(Example 3)
The cylindrical molded body similar to that molded in Example 1 was sintered in a vacuum at a temperature of 1550 ° C. for 3 hours. The sintered body thus obtained was processed with a cylindrical grinder to a diameter of 15 mm and a surface grinder to a height of 5 mm, and this processed plane was further roughened by sandblasting with # 200 alumina particles. It was processed. This surface was buffed with 20 μm diamond powder. The processed surface had a saturation index b * of 2.7, a lightness index L * of 45, a surface roughness Ra of 0.52, and a reflectance of 9.2. The results are shown in Table 1. When a transparent glass substrate coated with a resist film was placed on the surface of this test piece and the pattern was exposed, it was possible to form a clean rectangular cross-section pattern without causing problems such as line breakage due to double exposure. did it.

(Comparative Example 3)
10 kg of α-alumina powder with a purity of 99.99%, 30 kg of ion exchange water (solvent), 150 g of magnesium oxide, 50 g of a dispersant (ammonium polycarboxylate), 3000 g of a 10 wt% solution of polyvinyl alcohol as a binder, and polyethylene glycol as a plasticizer 200 g of # 400 was stirred and mixed in a ball mill for 24 hours to prepare a slurry. This slurry was spray-dried with a spray dryer to produce granules having an average particle size of 60 μm. The granules were conditioned to a moisture content of 0.5% by weight and then subjected to rubber press molding with a molding pressure of 1.0 ton / cm ² to produce a cylindrical molded body having a diameter of 20 mm and a height of 10 mm. Next, the cylindrical molded body thus obtained was sintered in the atmosphere at a temperature of 1600 ° C. for 3 hours. The sintered body thus obtained was processed with a cylindrical grinder to a diameter of 15 mm and a surface grinder to a height of 5 mm, and this processed plane was further sandblasted with # 200 alumina particles. The surface roughening process was performed using it. The processed surface was processed with a cloth buff using 20 μm diamond powder, and further finished with a 6 μm diamond powder. At this time, the saturation index b * was 4.8, the lightness index L * was 91, the surface roughness Ra was 0.18 μm, and the total reflectance was 83.2%. The results are shown in Table 1. When a transparent glass substrate coated with a resist film was placed on the test piece in the same manner as in Example 1 and pattern exposure was performed, the pattern faded due to double exposure, causing line breakage.

The substrate holder for exposure processing of the present invention is useful as a precision member for electronic parts, parts for semiconductor manufacturing equipment, parts for liquid crystal manufacturing equipment, and various measuring devices, particularly for manufacturing semiconductor elements and liquid crystal displays. It is suitably used for an exposure apparatus or the like.

Claims (7)

  At least the substrate holding side surface is made of ceramics, the saturation index b * of the substrate holding side surface is positive, the lightness index L * is 70 or less, and the surface roughness Ra is 0.6 μm or less. A substrate holder for exposure processing.   2. The substrate holder for exposure processing according to claim 1, wherein the total reflectance in the light wavelength range of 250 to 550 nm on the surface of the substrate holding side is 13% or less.   3. The substrate holder for exposure processing according to claim 1, wherein the crystal grain size of the ceramic constituting at least the holding side surface of the substrate is 3 [mu] m or more.   4. The substrate holder for exposure processing according to claim 1, wherein the main component of the ceramic is silicon carbide or alumina. The composition includes at least one additive selected from the group consisting of Fe ₂ O ₃ , Mn ₂ O ₃ , Cr ₂ O ₃ , CoO, TiO ₂ , CuO, NiO, TiC, SiC, and C. The substrate holder for exposure processing according to any one of 1 to 4.   6. The substrate holder for exposure processing according to claim 1, wherein the substrate placed on the substrate holder is a substrate irradiated with illumination light. An exposure characterized in that at least the surface on the substrate holding side has a substrate holding pattern processed into a base material made of ceramics with a positive chroma index b *, and then the processed surface is polished with free abrasive grains A method of manufacturing a substrate holder for processing.