JP2018019017A - Member for placement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member for placement having a low index of reflection, and capable of dealing with further improvement of exposure accuracy.SOLUTION: A member for placement includes multiple projections having a placement surface on one side of a tabular body, and is composed of aluminum oxide ceramic containing an oxide of manganese, an oxide of cobalt and an oxide of silicon. Content of the oxide of manganese is 2-6 mass%, content of the oxide of cobalt is 0.6-2 mass%, and content of the oxide of silicon is 0.02-3 mass%.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a mounting member such as a vacuum chuck for mounting a light-transmitting substrate that is an object to be processed in an exposure process of a semiconductor manufacturing process.

  In an exposure apparatus for manufacturing a light transmissive substrate such as a liquid crystal display working substrate, as a mounting member for the light transmissive substrate, ceramics exhibiting black color to suppress light reflection and improve exposure accuracy The low reflection member which consists of is used.

  As a ceramic used for such a low reflection member, Patent Document 1 contains 80 to 88% by mass of alumina, and at least one selected from Co, Mn, Fe, and Ti is 8 in terms of oxide. An alumina sintered body containing ˜20% by mass has been proposed.

JP 2011-168420 A

  The alumina sintered body proposed in Patent Document 1 has a lowest reflectance of 7% in the wavelength range of 400 nm to 600 nm. The mounting member used in the current exposure process is required to have a lower reflectance in order to further improve the exposure accuracy.

  The mounting member according to the present disclosure includes a plurality of protrusions having a mounting surface on a first surface of a plate-like body, and is made of an aluminum oxide ceramic containing manganese oxide, cobalt oxide, and silicon oxide. Become. The manganese oxide content is 2% by mass or more and 6% by mass or less, the cobalt oxide content is 0.6% by mass or more and 2% by mass or less, and the silicon oxide is It is 0.02 mass% or more and 3 mass% or less.

  Since the mounting member of the present embodiment has a low reflectance in the wavelength range of 400 nm to 600 nm, it can cope with further improvement in exposure accuracy.

It is a perspective view which shows an example of the member for mounting of this embodiment.

Hereinafter, the mounting member of the present embodiment will be described in detail with reference to the drawings.
A mounting member 10 shown in FIG. 1 includes a plurality of protrusions 2 each having a mounting surface 2 a on a first surface 1 a (hereinafter referred to as a main surface 1 a) of a plate-like body 1. The plate-like body 1 includes a plurality of suction holes 3 penetrating in the thickness direction. The suction holes 3 are connected to a vacuum suction device (not shown) and are sucked through the suction holes 3 by the vacuum suction device. Thus, the workpiece (not shown) can be adsorbed and fixed. In this case, the space between the main surface 1a and the object to be processed serves as a flow path for sucking gas.

The protrusion 2 is a pin-like protrusion, and a workpiece such as a light transmissive substrate is placed on the placement surface 2a. Then, by placing the object to be treated on the placement surface 2a having the shape shown in FIG. 1, the object to be treated and the surface to be placed are placed rather than placing on the flat surface having no projection. The possibility of dust being caught between them is reduced.

The mounting member 10 of the present embodiment is made of an aluminum oxide ceramic containing manganese oxide, cobalt oxide, and silicon oxide. Here, the aluminum oxide ceramics refers to ceramics having a content of aluminum oxide (Al ₂ O ₃ ) of 89% by mass or more out of a total of 100% by mass of all components constituting the ceramics.

  And the oxide of manganese and the oxide of cobalt which are contained in the aluminum oxide ceramics which comprise the member 10 for mounting of this embodiment are coloring components. The manganese oxide content is 2% by mass or more and 6% by mass or less, and the cobalt oxide content is 0.6% by mass or more and 2% by mass or less. Since the mounting member 10 according to the present embodiment includes such a coloring component, the color tone can be dark (black), and thus the reflectance in the wavelength range of 400 nm to 600 nm is low. Therefore, the mounting member 10 of the present embodiment can improve the exposure accuracy. In addition, the reflectance here is diffuse reflectance, and is simply described as reflectance below.

  Furthermore, the mounting member 10 of the present embodiment has a low reflectance at a wavelength of 360 nm, for example, as low as 5.5% or less, and can be used for exposure with low-wavelength ultraviolet light, which has been increasingly demanded in recent years. it can.

  Here, the oxide of manganese absorbs light, and in the case of an aluminum oxide ceramic whose coloring component is only an oxide of manganese, it exhibits a red color. Further, the cobalt oxide absorbs light, and in the case of the aluminum oxide ceramics in which the coloring component is only the cobalt oxide, it exhibits blue or green depending on the degree of oxidation. By setting the contents of the manganese oxide and the cobalt oxide in the above ranges, the main surface 1a and the mounting surface 2a can be black with low reflectance.

Specifically, the main surface 1a and the mounting surface 2a of the mounting member 10 of the present embodiment have a lightness index L ^* of 32 or less in the CIE 1976 L * a * b * color space, and a chromaticness index a ^* , All of b ^* are -4 or more and 4 or less.

  Since the main surface 1a and the mounting surface 2a of the mounting member 10 of the present embodiment are not only in the wavelength range of 360 nm to 440 nm but also in the entire visible light region, there is a strong tendency to achromatic black. The rate can be reduced. Furthermore, uneven color is suppressed by increasing the tendency of achromatic color.

The values of the lightness index L ^* and the chromaticness index a ^* , b ^* can be obtained according to JIS Z 8722: 2009. For example, a spectral color difference meter (NF77 manufactured by Nippon Denshoku Industries Co., Ltd. or its successor model) is used, and the measurement conditions may be set to a CIE standard light source D65 and a viewing angle of 2 °.

  In addition, the oxide of silicon forms a grain boundary phase that bonds crystals and improves fracture toughness, and combines with coloring oxides of manganese and cobalt to suppress decolorization of the colorant. It is an ingredient to do. The content of silicon oxide is 0.02 mass% or more and 3 mass% or less. When the content of silicon oxide is 0.02% by mass or more, a grain boundary phase that bonds crystals is formed to improve fracture toughness, and manganese oxide and cobalt oxide that are coloring components In combination, the decolorization of the colorant is suppressed, but if it exceeds 3% by mass, there is a possibility that an aluminosilicate that becomes a stain and tends to remain on the main surface 1a or the mounting surface 2a may be generated.

  In addition to the above components, the aluminum oxide ceramics may act as a sintering aid, and may contain magnesium oxide and calcium oxide as components mainly constituting the grain boundary phase. The total content of magnesium oxide and calcium oxide is, for example, 0.1% by mass or more and 0.2% by mass or less, out of a total of 100% by mass of all components constituting the aluminum oxide ceramic.

The content of each component described above is determined by crushing a part of the aluminum oxide ceramics, dissolving the obtained powder in a solution such as hydrochloric acid, and then using an ICP (Inductively Coupled Plasma) emission spectrometer (ICP, for example, ( It is calculated | required by converting each into an oxide from content of the metal component obtained using Shimadzu Corporation (ICPS-8100). For example, the Al content is converted to Al ₂ O ₃ , and the Co content is converted to Co ₃ O ₄ .

  In the mounting member 10 of the present embodiment, the main surface 1a of the substrate 1 has a cutting level difference (Rδc) between a load length rate of 25% and a load length rate of 75% in the roughness curve. Is preferably 1.1 μm or more.

  Here, the cutting level difference (Rδc) is the height of cutting levels C (Rrm1) and C (Rrm2) respectively corresponding to the load length ratios Rmr1 and Rmr2 in the roughness curve defined in JIS B0601: 2001. It is a difference in direction. When the cutting level difference (Rδc) is large, the unevenness of the surface to be measured becomes large, and when small, the unevenness of the surface becomes small. When the cutting level difference (Rδc) is 1.1 μm or more, the reflectance can be lowered and the scattering of particles can be suppressed.

  The cutting level difference (Rδc) on the main surface 1a of the substrate 1 is preferably 2.42 μm or less. When the cutting level difference (Rδc) on the main surface 1a is 2.42 μm or less, the convex portions generated on the main surface 1a are less likely to be steep, so that it is difficult for particles to be generated from the tips of the convex portions.

  Further, the main surface 1a of the plate-like body 1 in the mounting member 10 of the present embodiment may have a root mean square roughness (Rq) of 1.11 μm or more and 2.04 μm or less. When the root mean square roughness (Rq) of the main surface 1a is 1.11 μm or more and 2.04 μm or less, the reflectance can be lowered and the scattering of particles can be suppressed.

  In addition, the main surface 1a of the plate-like body 1 in the mounting member 10 of the present embodiment may have an arithmetic average roughness (Ra) of 0.81 μm or more and 1.52 μm or less. When the arithmetic average roughness (Ra) of the main surface 1a is 0.81 μm or more and 1.52 μm or less, the reflectance can be further lowered and the generation of particles can be suppressed.

  Furthermore, the mounting surface 2a of the protrusion 2 in the mounting member 10 of the present embodiment has a cutting level difference (Rδc) between a load length rate of 25% and a load length rate of 75% in the roughness curve. ) May be 1.1 μm or more. When the cutting level difference (Rδc) is 1.1 μm or more, the reflectance can be lowered and the scattering of particles can be suppressed.

  Further, the cutting level difference (Rδc) on the mounting surface 2a of the protrusion 2 may be 2.42 μm or less. When the cutting level difference (Rδc) on the mounting surface 2a is 2.42 μm or less, the convex portion generated on the mounting surface 2a is not likely to be steep, so that it is difficult for particles to be generated from the tip of the convex portion. It is hard to damage.

Furthermore, the mounting surface 2a of the protrusion 2 in the mounting member 10 of the present embodiment may have a root mean square roughness (Rq) of 1.11 μm or more and 2.04 μm or less. When the root mean square roughness (Rq) of the mounting surface 2a is 1.11 μm or more and 2.04 μm or less, the reflectance can be lowered and the generation of particles can be suppressed. Moreover, it becomes difficult to damage to a to-be-processed object.

  Moreover, 0.81 micrometer or more and 1.52 micrometers or less may be sufficient as arithmetic mean roughness (Ra) for the mounting surface 2a of the protrusion part 2 in the member 10 for mounting of this embodiment. When the arithmetic average roughness (Ra) of the mounting surface 2a is 0.81 μm or more and 1.52 μm or less, the reflectance can be further lowered and the generation of particles can be suppressed. Moreover, it becomes difficult to damage to a to-be-processed object.

  Cutting level difference (Rδc), root mean square roughness (Rq) and arithmetic mean between 25% load length ratio and 75% load length ratio in the roughness curves of main surface 1a and mounting surface 2a The roughness (Ra) may be determined using a laser microscope (for example, Keyence Corporation (VK-9510)) in accordance with JIS B 0601: 2001. When using the laser microscope VK-9510, for example, the measurement mode is color depth, the measurement magnification is 1000 times, the measurement range per place is 281 μm × 210 μm, the measurement pitch is 0.05 μm, and the λs contour curve filter is 2.5 μm. The λc contour curve filter may be obtained as 0.08 mm.

Next, an example of the manufacturing method of the mounting member will be described.
First, aluminum oxide (Al ₂ O ₃ ) powder, which is a main ingredient, silicon oxide (SiO ₂ ) powder as a sintering aid, manganese oxide (MnO ₂ ) powder and cobalt oxide (Co ₃ O ₄ ) as coloring components Prepare powder.

Next, a desired amount of these powders are weighed into primary raw material powders. For example, the sintering aid is weighed so that the total content of silicon converted to SiO ₂ is 0.02% by mass or more and 3% by mass or less out of 100% by mass of all components constituting the ceramic sintered body. To do. In addition, the coloring component is a content obtained by converting manganese to MnO ₂ in 100% by mass of all components constituting the ceramic sintered body, 2% by mass to 6% by mass or less, and cobalt to Co ₃ O ₄ Is weighed so that it becomes 0.6 mass% or more and 2 mass% or less. Then, the balance is weighed so that aluminum oxide _(Al 2 _{O 3)} powder. By setting the content of the coloring component in such a range, the lightness index L ^* in the CIE 1976 L * a * b * color space of the main surface 1a and the mounting surface 2a is 32 or less, and the chromaticness index a ^* , All of b ^* can be a mounting member that is -4 or more and 4 or less.

  Next, 0.1 parts by mass or more and 1 part by mass or less of a binder such as PEG (polyethylene glycol) and 100 parts by mass of solvent are weighed and mixed with the primary material powder with respect to 100 parts by mass of the primary material powder. -Stir to obtain a slurry.

  Thereafter, the slurry is sprayed and granulated using a spray granulator (spray dryer) to obtain granules, and then a molded body having a desired shape is formed by a powder press molding method or an isostatic press molding method (rubber press method). .

Next, the obtained molded body is subjected to cutting as necessary, and is fired while being held in an air (oxidation) atmosphere, for example, at a temperature of 1400 ° C. or higher and 1500 ° C. or lower for a desired time. It is possible to obtain a mounting member precursor having a plurality of protrusions on one surface thereof. And after giving the blast process to the surface of the obtained precursor, a main surface can be made into a desired surface property by giving shot peening by fine powder for precision grindings, such as glass beads and ceramic beads. Further, the top surface of the protrusion portion of the obtained precursor is sequentially subjected to blasting and grinding with a surface grinder, and then the shot surface is subjected to the above-described shot peening so that the mounting surface has a desired surface property. it can.

  In order to set the cutting level difference (Rδc) of the main surface to 1.1 μm or more and the cutting level difference (Rδc) of the mounting surface to 1.1 μm or more, it is specified by the sedimentation test method of JIS R 6001: 1998. The fine pulverizing powder having a particle size of # 500 or more and # 1000 or less may be appropriately selected and shot peened.

  The present invention is not limited to the above-described embodiments, and various modifications, improvements, combinations, and the like can be made without departing from the scope of the present invention.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

First, aluminum oxide (Al ₂ O ₃ ) powder as a main ingredient, silicon oxide (SiO ₂ ) powder as a sintering aid, manganese oxide (MnO ₂ ) powder and cobalt oxide (Co ₃ O ₄ ) as coloring components. ) Prepared the powder.

Next, a desired amount of these powders was weighed to obtain a primary raw material powder. Here, the sintering aid was weighed so that the total content of silicon converted to SiO ₂ was 1.5% by mass out of 100% by mass of all components constituting the ceramic sintered body. Moreover, the coloring component has a content of 4% by mass of manganese converted to MnO ₂ and 100% by mass of cobalt converted to Co ₃ O ₄ out of 100% by mass of all components constituting the ceramic sintered body. Weighed so as to be mass%. Then, the remainder was weighed so that aluminum oxide _(Al 2 _{O 3).}

  Next, with respect to 100 parts by mass of the primary raw material powder, 0.5 parts by mass of a binder such as PEG (polyethylene glycol) and 100 parts by mass of a solvent are weighed and mixed and stirred together with the primary raw material powder. A slurry was obtained.

  Thereafter, the slurry was sprayed and granulated using a spray granulator (spray dryer) to obtain granules, and then a compact was molded by a hydrostatic pressure press molding method (rubber press method).

  Next, the obtained molded body is subjected to cutting, and held in an air (oxidation) atmosphere and fired at 1450 ° C., thereby providing a substrate and a plurality of protrusions on one surface of the substrate. Sample No. which is a precursor of the mounting member. 1 was obtained.

As comparative examples, aluminum oxide (Al ₂ O ₃ ) powder, which is a main component material, and cobalt oxide (Co ₃ O ₄ ) powder, manganese oxide (MnO ₂ ) powder, iron oxide (Fe ₂ ) as coloring components. O ₃ ) powder and titanium oxide (TiO ₂ ) powder were prepared.

Next, a desired amount of these powders was weighed to obtain a primary raw material powder. Here, among 100% by mass of all components constituting the ceramic sintered body, the content of aluminum converted to Al ₂ O ₃ is 83% by mass, and the coloring component has a content of cobalt converted to Co ₃ O _4. 3.9 wt%, manganese content of 3.9 mass% in terms of MnO _2, the iron amount containing the terms of _Fe 2 _{O 3} is 3.9 wt%, the content in terms of titanium TiO ₂ It weighed so that it might become 1.3 mass%. The balance is inevitable impurities.

  Next, for 100 parts by mass of the primary raw material powder, 50 parts by mass of a polyester resin emulsion (solid content 30% by mass), a total of 2 parts by mass of a dispersant and a thickener, and 15 parts by mass of a solvent. A slurry was obtained by weighing and mixing and stirring together with the primary raw material powder.

  Thereafter, the slurry was poured into a mold, dried and cured to obtain a molded body.

Next, the obtained molded body is subjected to cutting, and held in an air (oxidation) atmosphere and fired at 1450 ° C., thereby providing a substrate and a plurality of protrusions on one surface of the substrate. Sample No. which is a precursor of the mounting member. 2 was obtained. And sample no. 1 and sample no. The surface of the substrate 2 was subjected to blasting to make a main surface.
And using a handy type spectral color difference system (NF77 manufactured by Nippon Denshoku Industries Co., Ltd.), the light source is CIE standard light source D65, the viewing angle is 2 °, the measurement diameter is 2 mm, and the main surface in the wavelength region of 400 to 600 nm The reflectance was measured. Here, the reflectance is a diffuse reflectance at each wavelength. The results are shown in Table 1.
In addition, the content of the components constituting each sample is determined by crushing a part of the substrate including the main surface, dissolving the obtained powder in hydrochloric acid, and then ICP (Inductively Coupled Plasma) emission spectroscopic analyzer Table 1 shows the composition formula and the content obtained by converting each of the metal components obtained using Shimadzu Corporation (ICPS-8100) into oxides.

  From the results shown in Table 1, Sample No. 1 is made of an aluminum oxide ceramic containing manganese oxide, cobalt oxide and silicon oxide, and the content of manganese oxide is 2% by mass or more and 6% by mass or less. Since the content is 0.6 mass% or more and 2 mass% or less and the content of silicon oxide is 0.02 mass% or more and 3 mass% or less, the maximum diffuse reflectance of the main surface is satisfied. The value was as low as 6.6%, and it was found that the exposure accuracy could be improved.

  Moreover, as a result of measuring the reflectance of a main surface by producing a mounting member in which each oxide was set to an upper limit and a lower limit by the method described above, the maximum value of the reflectance was less than 7% in all cases. there were.

  A precursor of the mounting member was produced by the same method as shown in Example 1.

  Then, after blasting the surface of the precursor substrate, the first surface of the plate-like body constituting the mounting member was formed by performing shot peening with glass beads. Here, the particle size of glass beads and the time for performing shot peening were appropriately adjusted.

The cutting level difference (Rδc) between the load length ratio of 25% and the load length ratio of 75% in the roughness curve of the main surface is in accordance with JIS B 0601: 2001, and a laser microscope (Keyence Corporation). (VK-9510)) and the values are shown in Table 2. Here, the measurement conditions are as follows: measurement mode is color depth, measurement magnification is 1000 times, measurement range is 281 μm × 210 μm, measurement pitch is 0.05 μm, λs contour curve filter is 2.5 μm, and λc contour curve filter is 0. It was set to 08 mm.

  Further, the diffuse reflectance of the main surface at a wavelength of 500 nm was measured by the same method as that shown in Example 1, and the maximum value of the diffuse reflectance is shown in Table 2.

  From the results shown in Table 2, sample No. In Nos. 4 to 7, since the cutting level difference (Rδc) of the main surface of the substrate is 1.1 μm or more, it is understood that the diffuse reflectance of the main surface is as low as 6.37% or less and the exposure accuracy can be improved. It was.

  A precursor of the mounting member was produced by the same method as shown in Example 1.

  And after carrying out the blasting and the grinding process by the surface grinder sequentially on the top surface of the projection part of the precursor, the mounting surface of the projecting part constituting the mounting member by performing the above-described shot peening and did. Here, the particle size of glass beads and the time for performing shot peening were appropriately adjusted.

The cutting level difference (Rδc) between the load length ratio of 25% and the load length ratio of 75% in the roughness curve of the mounting surface is obtained by the same method as shown in Example 2, and the value Are shown in Table 3.
Moreover, the diffuse reflectance of the placing surface at a wavelength of 500 nm was measured by the same method as the method shown in Example 1 except that the measuring surface was the placing surface, and the maximum value of the diffuse reflectance was shown in Table 3. It was shown to.

  From the results shown in Table 3, Sample No. In Nos. 9 to 12, since the cutting level difference (Rδc) of the mounting surface of the protruding portion is 1.1 μm or more, the diffuse reflectance of the mounting surface is as low as 6.25% or less, and the exposure accuracy can be improved. I understood it.

DESCRIPTION OF SYMBOLS 1 Plate-shaped body 1a Main surface 2 Protruding part 2a Mounting surface 3 Suction hole 10 Mounting member

Claims (3)

The first surface of the plate-like body is provided with a plurality of protrusions having a mounting surface,
It consists of an aluminum oxide ceramic containing a manganese oxide, a cobalt oxide and a silicon oxide, the manganese oxide content is 2 mass% or more and 6 mass% or less, and the cobalt oxide content The mounting member, wherein the amount is 0.6 mass% or more and 2 mass% or less, and the content of the silicon oxide is 0.02 mass% or more and 3 mass% or less.   2. The first surface has a cutting level difference (Rδc) between a load length ratio of 25% and a load length ratio of 75% in a roughness curve of 1.1 μm or more. 2. The mounting member according to 1.   2. The mounting surface according to claim 1, wherein a cutting level difference (Rδc) between a load length ratio of 25% and a load length ratio of 75% in the roughness curve is 1.1 μm or more. Alternatively, the mounting member according to claim 2.