JP6608750B2 - Mounting member - Google Patents

Description

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

  In an exposure apparatus for manufacturing a light-transmitting substrate such as a liquid crystal display working substrate, colored ceramics are used as a member for mounting the light-transmitting substrate in order to suppress light reflection and improve exposure accuracy. The low reflection member which consists of is used.

  As such a low reflection member, in Patent Document 1, the lightness index is 45 or less, the oxide compound is made of ceramics having the highest peak in the X-ray diffraction chart, and the refractive index of the compound is 1.72 or less. The low reflection member which is is proposed.

Japanese Patent Laid-Open No. 2015-2111073

  The low reflection member proposed in Patent Document 1 has a reflectance of 6.8% or more and 9.6% or less. The mounting member used in this exposure process is required to have a lower reflectance in order to further improve the exposure accuracy.

The mounting member according to the present embodiment includes a plurality of protrusions having a mounting surface on one main surface of the substrate, and is made of an aluminum oxide ceramic. The aluminum oxide ceramic includes cobalt, iron, nickel, and titanium. the content of the oxide only containing an oxide of cobalt, cobalt (Co) and Co ₃ O ₄ 12 wt% 8 wt% or more in terms of the values below, the content of oxides of iron, iron ( Fe) is 4% by mass to 6% by mass in terms of Fe ₂ O ₃ , and the nickel oxide content is 3% by mass to 4% by mass in terms of nickel (Ni) converted to NiO. The content of titanium oxide is 1% by mass or more and 2% by mass or less in terms of titanium (Ti) converted to TiO ₂ , and the main surface has a load length ratio of 75% in the roughness curve and 75%. % Load length
The cutting level difference (Rδc) between the ratio is 1.1 μm or more and 2.22 μm or less, and the placement surface described above has a load length ratio of 25% and a load length ratio of 75% in the roughness curve. The cutting level difference (Rδc) is 1.1 μm or more and 1.53 μm or less .

  Since the mounting member of the present embodiment has a low reflectance in the wavelength range of 360 nm to 440 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 having a mounting surface 2 a on one main surface 1 a of a substrate 1. The substrate 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. 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 workpiece on the placement surface 2 a having the shape shown in FIG. 1, there is a risk that dust may be caught between the workpiece and the placement surface, rather than placing on the flat surface. Is reduced.

  The mounting member 10 of the present embodiment is made of an aluminum oxide ceramic. Here, the aluminum oxide ceramics refers to ceramics whose main component is an aluminum oxide content of 52% by mass or more out of a total of 100% by mass of all components constituting the ceramics.

  And the aluminum oxide ceramics which comprise the member 10 for mounting of this embodiment contain the oxide of cobalt, iron, nickel, and titanium. Since the oxides of cobalt, iron, nickel and titanium are coloring components and the color tone of the aluminum oxide ceramics can be made dark (black), the reflectance in the wavelength region of 360 nm to 440 nm (hereinafter, within this range). The reflectance in the wavelength region is sometimes simply referred to as reflectance. Therefore, the mounting member 10 of the present embodiment can improve the exposure accuracy.

The content of the cobalt oxide is, for example, 8% by mass or more and 12% by mass or less in terms of cobalt (Co) converted to Co ₃ O ₄ . The content of the oxide of iron, for example, is iron (Fe) less than 6 wt% 4 wt% or more values in terms of _Fe 2 _{O 3.} Moreover, content of the oxide of nickel is 3 mass% or more and 4 mass% or less by the value which converted nickel (Ni) to NiO, for example. The content of titanium oxide is, for example, 1% by mass or more and 2% by mass or less in terms of titanium (Ti) converted to TiO ₂ .

In addition to the above components, the aluminum oxide ceramics acts as a sintering aid, and may contain silicon, magnesium, and calcium oxides as components that mainly constitute the grain boundary phase. Hereinafter, oxides of silicon, magnesium, and calcium (SiO ₂ , MgO, CaO) are collectively referred to as auxiliary components. The content of the auxiliary component is, for example, 0.6% by mass or more and 2% by mass or less, out of a total of 100% by mass of all components constituting the aluminum oxide ceramic.

The content of the main component, coloring component and auxiliary 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 ICP (Inductively Coupled Plasma) emission spectroscopy. It is calculated | required by each converting into content from the content of the metal component obtained using an analyzer (ICP, for example, Shimadzu Corporation make (ICPS-8100)). For example, the content of Al is converted to Al ₂ O ₃ , and the content of Co is converted to Co ₃ O ₄ .

Further, when the aluminum oxide ceramics contain at least one of cobalt spinel, iron spinel and nickel spinel in the grain boundary phase, the refractive index of these spinels is about 1.74 to 1.80, and the aluminum oxide ceramics Since the refractive index is close to 1.77, the reflectance can be further reduced. Cobalt spinel, iron spinel, and nickel spinel may have an indefinite ratio in composition formula, but are preferably CoAl ₂ O ₄ , FeAl ₂ O _4, and NiAl ₂ O ₄ in which the composition formula is a constant ratio.

The anorthite whose composition formula is shown as CaAl ₂ Si ₂ O ₅ has a refractive index of 1.58, a large difference from the refractive index of aluminum oxide, and a high reflectance, so that the mounting member 10 More preferably, it does not contain anorthite.

In addition, when aluminum oxide ceramics contain aluminum titanate in the grain boundary phase, abnormal grain growth of aluminum oxide crystal grains can be suppressed, so that the mechanical strength of aluminum oxide ceramics is increased. Can do. The compositional formula of aluminum titanate may be non-stoichiometric, but is preferably Al ₂ TiO ₅ whose compositional formula is constant.

  Cobalt spinel, iron spinel, nickel spinel and aluminum titanate can be identified using an X-ray diffractometer (XRD). Moreover, what is necessary is just to confirm an existing location using an X-ray microanalyzer (EPMA) about a grain boundary phase.

  In particular, in the mounting member 10 of the present embodiment, aluminum oxide is 52% by mass to 80% by mass, and the total content of cobalt spinel, iron spinel, and nickel spinel is 19% by mass to 47% by mass. In addition, the content of aluminum titanate is preferably 1% by mass or more and 5% by mass or less. When each content of aluminum oxide, cobalt spinel, iron spinel, nickel spinel and aluminum titanate satisfies the above-mentioned range, it can have low reflectance and high mechanical strength. The contents of cobalt spinel, iron spinel, nickel spinel and aluminum titanate may be obtained by Rietveld analysis.

  Further, in the mounting member 10 of the present embodiment, the main surface 1a has a cutting level difference (Rδc) between a load length ratio of 25% and a load length ratio of 75% in the roughness curve of 1. It is suitable that it is 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 generation of particles can be suppressed.

  Further, the cutting level difference (Rδc) on the main surface 1a is preferably 2.22 μm or less. When the cutting level difference (Rδc) on the main surface 1a is 2.22 μm or less, the convex portions generated on the main surface 1a are unlikely to be steep, and thus particles are hardly generated from the tips of the convex portions.

  Moreover, it is suitable for the main surface 1a in the member 10 for mounting of this embodiment that a root mean square roughness (Rq) is 0.82 micrometer or more and 1.74 micrometers or less. When the root mean square roughness (Rq) of the main surface 1a is 0.82 μm or more and 1.74 μm or less, the reflectance can be lowered and the generation of particles can be suppressed.

  Moreover, it is suitable for the main surface 1a in the member 10 for mounting of this embodiment that arithmetic mean roughness (Ra) is 0.65 micrometer or more and 1.35 micrometers or less. When the arithmetic average roughness (Ra) of the main surface 1a is 0.65 μm or more and 1.35 μm or less, the reflectance can be further lowered and the generation of particles can be suppressed.

  Further, the mounting surface 2a of the mounting member 10 of the present embodiment has a cutting level difference (Rδc) between a load length ratio of 25% and a load length ratio of 75% in the roughness curve of 1. It is suitable that it is 1 μm or more. When the cutting level difference (Rδc) is 1.1 μm or more, the reflectance can be lowered.

  The cutting level difference (Rδc) on the mounting surface 2a is preferably 1.53 μm or less. When the cutting level difference (Rδc) on the mounting surface 2a is 1.53 μm or less, the convex portion generated on the mounting surface 2a is less likely to be steep, so that it is difficult for particles to be generated from the tip of the convex portion and It is hard to damage.

  Moreover, it is suitable for the mounting surface 2a in the mounting member 10 of the present embodiment that the root mean square roughness (Rq) is 0.82 μm or more and 1.74 μm or less. When the root mean square roughness (Rq) of the mounting surface 2a is 0.82 μm or more and 1.74 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, it is suitable that the mounting surface 2a in the mounting member 10 of the present embodiment has an arithmetic average roughness (Ra) of 0.65 μm or more and 1.35 μm or less. When the arithmetic average roughness (Ra) of the mounting surface 2a is 0.65 μm or more and 1.35 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.

Further, in the mounting member 10 of the present embodiment, the main surface 1a and the mounting surface 2a have a lightness index L ^* in the CIE 1976 L * a * b * color space of 30 or less, and a chromaticness index a ^* , b. It is preferable that all ^* are -2 or more and 2 or less.

  In such a range, the main surface 1a and the mounting surface 2a are not only in the wavelength range of 360 nm to 440 nm but also in the entire visible light region, so the tendency to achromatic black color becomes strong. 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 °.

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 component material, and cobalt oxide (Co ₃ O ₄ ) powder, iron oxide (Fe ₂ O ₃ ) powder, nickel oxide (NiO) powder, and oxidation as coloring components A titanium (TiO ₂ ) powder is prepared. In addition, calcium carbonate (CaCO ₃ ) powder, magnesium hydroxide (Mg (OH) ₂ ) powder, and silicon oxide (SiO ₂ ) powder are prepared as sintering aids.

Next, a desired amount of these powders are weighed into primary raw material powders. For example, the sintering aid has a total content of 0.6 in terms of calcium converted to CaO, magnesium converted to MgO, and silicon converted to SiO ₂ out of 100% by mass of the total components constituting the ceramic sintered body. Weigh so that it is at least 2% by mass. Further, coloring components, out of all components 100% by mass of the ceramic sintered body, the content obtained by converting the cobalt in _Co 3 _{O 4} is 8 mass% or more and 12 mass% or less, in terms of the iron _Fe 2 _{O 3} 4 mass% or more and 6 mass% or less, the content of nickel converted to NiO is 3 mass% or more and 4 mass% or less, and the content of titanium converted to TiO ₂ is 1 mass% or more and 2 mass% or less. Weigh so that 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 and the mounting surface is 3
The mounting member may be 0 or less, and both chromaticness indices a ^* and b ^* are −2 or more and 2 or less.

In order to obtain a mounting member in which the grain boundary phase of the ceramic sintered body contains at least one of cobalt spinel, iron spinel, and nickel spinel, first, aluminum oxide (Al ₂ O ₃ ) powder is classified, and average grains An aluminum oxide (Al ₂ O ₃ ) powder having a small diameter is obtained. Then, cobalt oxide (Co ₃ O ₄ ) powder, iron oxide (Fe ₂ O ₃ ) powder, and nickel oxide (NiO) powder having the above-described content range are made of aluminum oxide (Al ₂ O ₃ ) powder having a small average particle diameter. Then, after mixing and calcining at a temperature of 1100 ° C. or higher and 1300 ° C. or lower, a powder pulverized to a desired average particle size using a pulverizer such as a ball mill may be used.

In order to obtain a mounting member in which the grain boundary phase of the ceramic sintered body contains aluminum titanate, titanium oxide (TiO ₂ ) powder having a content range described above is mixed, and the temperature is 1100 ° C. or higher and 1300 ° C. or lower. After calcination synthesis, a powder pulverized to a desired average particle size using a pulverizer such as a ball mill may be used.

  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 raw material powder with respect to 100 parts by mass of the primary raw 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 atmosphere (oxidation) atmosphere, for example, at a temperature of 1400 ° C. or higher and 1500 ° C. or lower for a desired time. The precursor of the mounting member provided with a plurality of protrusions on the surface can be obtained. Then, after blasting the surface of the obtained precursor substrate, the substrate constituting the mounting member of the present embodiment is subjected to shot peening with fine powder for precision polishing such as glass beads and ceramic beads. It can be the main surface. In addition, the top surface of the obtained protrusion of the precursor is sequentially subjected to blasting and grinding with a surface grinder, and then the above-described shot peening is performed to place the protrusion constituting the mounting member. A surface is obtained, and the mounting member of this embodiment can be obtained.

  In order to set the cutting level difference (Rδc) of the main surface 1a to 1.1 μm or more and the cutting level difference (Rδc) of the mounting surface 2a to 1.1 μm or more, the sedimentation test method of JIS R 6001: 1998 It is only necessary to appropriately select fine polishing powder having a particle size of # 500 or more and # 1000 or less as defined in (1) above and to perform shot peening on one surface of the substrate and the top surface of the protruding portion.

  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, which is a main component material, and cobalt oxide (Co ₃ O ₄ ) powder, iron oxide (Fe ₂ O ₃ ) powder, nickel oxide (NiO) powder, and oxidation as coloring components Titanium (TiO ₂ ) powder was prepared. Further, as a sintering aid, calcium carbonate (CaCO ₃ ) powder, magnesium hydroxide (Mg (OH) ₂ ) powder and silicon oxide (S
iO ₂ ) powder was prepared.

Next, a desired amount of these powders was weighed to obtain a primary raw material powder. Here, the sintering aid has a total content of 100% by mass of all components constituting the ceramic sintered body, in which calcium is converted to CaO, magnesium is converted to MgO, and silicon is converted to SiO ₂ . It weighed so that it might become 3 mass%. In addition, the content of the coloring component is 9.5% by mass in which cobalt is converted to Co ₃ O ₄ and 100% by mass in terms of iron is converted to Fe ₂ O ₃ in 100% by mass of all components constituting the ceramic sintered body. Was 5% by mass, the content of nickel converted to NiO was 3.5% by mass, and the content of titanium converted to TiO ₂ was 1.5% by mass. Then, the remainder was weighed so that aluminum oxide _(Al 2 _{O 3)} powder.

  Next, with respect to 100 parts by mass of the primary raw material powder, 0.5 parts by mass or less 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. To obtain a slurry.

  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.

Further, as comparative examples, aluminum oxide (Al ₂ O ₃ ) powder, which is a main component material, and manganese carbonate (MnCO ₃ ) powder, iron oxide (Fe ₂ O ₃ ) powder, chromium oxide (Cr ₂ ) as coloring components. O ₃₎ was prepared powder. In addition, calcium carbonate (CaCO ₃ ) powder, magnesium hydroxide (Mg (OH) ₂ ) powder, and silicon oxide (SiO ₂ ) powder were prepared as sintering aids.

Next, a desired amount of these powders was weighed to obtain a primary raw material powder. Here, the sintering aid is CaO and MgO, respectively, out of 100% by mass of all components constituting the ceramic sintered body.
, And weighed so that the total in terms of SiO 2 would be 1.5% by mass. Further, the coloring component was weighed so that the total amount of manganese converted to MnO ₂ , iron converted to Fe ₂ O 3, and Cr converted to Cr ₂ O 3 was 10% by mass, out of 100% by mass of all components constituting the ceramic sintered body. . Then, the remainder was weighed so that aluminum oxide _(Al 2 _{O 3)} powder.

  Next, 1 part by mass of PVA, 0.2 part by mass of dispersant, and 100 parts by mass of solvent are weighed with respect to 100 parts by mass of the primary raw material powder, and mixed and stirred together with the primary raw material powder. To obtain a slurry.

  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. 2 was obtained.
And sample no. After blasting the surfaces of the substrates 1 and 2 to make the main surface, the elements constituting the color components contained in the main surface are detected using an energy dispersive X-ray analyzer (EDS) The elements shown in Table 1 are represented by element symbols.

Further, using a spectrocolorimeter (CM-3700A manufactured by Konica Minolta), the reflectance of the main surface in the wavelength region of 360 to 440 nm with a light source of CIE standard light source D65, a viewing angle of 10 °, and an illumination diameter of 3 mm × 5 mm. The maximum reflectance was shown in Table 1.

  From the results shown in Table 1, Sample No. 1 is a mounting member made of a ceramic sintered body containing oxides of cobalt, iron, nickel and titanium, so that the reflectance of the main surface is as low as 6.5%, and the exposure accuracy can be improved. I understood.

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

  And after giving the blast process to the surface of the board | substrate of this precursor, it was set as the main surface of the board | substrate which comprises the member for mounting by performing shot peening by a glass bead. 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 reflectance of the main surface was measured by the same method as shown in Example 1, and the maximum value of the 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 was found that the reflectance of the main surface is as low as 6.2% or less and the exposure accuracy can be improved. .

  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.
Further, the reflectance of the mounting surface was measured by the same method as shown in Example 1, and the maximum value of the reflectance is shown in Table 3.

  From the results shown in Table 3, Sample No. For Nos. 9 to 12, since the cutting level difference (Rδc) of the mounting surface of the protrusion is 1.1 μm or more, the reflectance of the mounting surface is as low as 6.2% or less, and the exposure accuracy can be improved. I understood.

DESCRIPTION OF SYMBOLS 1 Substrate 1a Main surface 2 Protruding part 2a Mounting surface 3 Suction hole 10 Mounting member

Claims (3)

On one main surface of the substrate, a plurality of protrusions having a mounting surface, made of aluminum oxide ceramics, the aluminum oxide ceramics is cobalt, iron, look-containing oxides of nickel and titanium, oxides of cobalt The content of the product is 8% by mass to 12% by mass in terms of cobalt (Co) converted to Co ₃ O ₄ , and the content of the iron oxide is iron (Fe) converted to Fe ₂ O ₃ The content of nickel oxide is 4% by mass or more and 6% by mass or less, and the content of nickel oxide is 3% by mass or more and 4% by mass or less in terms of nickel (Ni) converted to NiO. The content of titanium oxide is titanium The value obtained by converting (Ti) to TiO ₂ is 1% by mass or more and 2% by mass or less, and the main surface is between a load length ratio of 25% and a load length ratio of 75% in the roughness curve. Cutting level difference (Rδc) is 1.1 μm or more 2 The mounting surface is 22 μm or less, and the mounting surface has a cutting level difference (Rδc) between a load length ratio of 25% and a load length ratio of 75% in the roughness curve of 1.1 μm or more and 1.53 μm or less. There is a mounting member.   The mounting member according to claim 1, wherein the aluminum oxide ceramics includes at least one of cobalt spinel, iron spinel, and nickel spinel in a grain boundary phase.   The mounting member according to claim 1, wherein the aluminum oxide ceramic contains aluminum titanate in a grain boundary phase.

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