JP2008120654A - Ceramic-coated member and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ceramic-coated member which is inhibited from occurrence of particles and has excellent corrosion resistance and durability and to provide a method of manufacturing the ceramic-coated member by which a ceramic film hardly causing occurrence of particles and having excellent corrosion resistance and durability is easily formed on a complicate shaped base material or a large-sized base material. <P>SOLUTION: The ceramic-coated member has structure in which the ceramic film having ≥98% purity, ≥0.05 μm and ≤10 μm film thickness and ≤50 nm average particle diameter is formed on the surface of the base material. The ceramic film is formed by wet-forming a coating film using a solution containing at least one kind of a metal alkoxide, an organic metal complex, an oxide nanoparticle or a non-oxide nanoparticle on the surface of the base material and after drying the coating film, applying heat treatment to the dried coating film at ≥300°C and ≤1,000°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ceramic coating member suitably used in, for example, a semiconductor manufacturing apparatus or an FPD (Flat Panel Display) manufacturing apparatus, and more specifically, a ceramic excellent in durability in which particle generation is suppressed when used in a corrosive environment. The present invention relates to a coating member and a manufacturing method thereof.

  In semiconductor device manufacturing apparatuses such as IC, LSI, VLSI, and flat panel display (FPD) manufacturing apparatuses such as liquid crystal display (LCD) and plasma display (PDP), silicon wafers and glass substrates (hereinafter referred to as “substrates”). In contrast, multiple processes such as cleaning processing for removing particles and metals, resist coating, exposure, development, film formation processing such as CVD sputtering, fine processing such as etching and dicing, and inspection processing such as line width measurement Is done as appropriate.

  Supplying process gas and cleaning gas in the transfer arm for carrying these processes, electrostatic chuck and vacuum chuck for attracting and holding the substrate, chamber for accommodating the substrate, film formation process and etching process For the various members such as the gas ejection nozzle and the gas dispersion plate, a material having excellent durability in the usage environment is selected.

  This is because when these device members are worn, corroded, etc. in each process, they become particles and directly adhere to the substrate, or after being attached to these device members, they are peeled off and adhered to the substrate. This is to prevent defects such as a short circuit between the wirings formed on the substrate.

  In order to suppress the generation of particles from such apparatus members, conventionally, for example, in an electrostatic chuck or a vacuum chuck, a protrusion or groove is formed by blasting or the like on the suction fixing surface of the substrate, and then this suction fixing. The surface is mirror-polished using abrasive grains and a buff to suppress the generation of particles from the adsorption fixed surface (see, for example, Patent Document 1).

  Moreover, the generation | occurrence | production of a particle is prevented by forming the film excellent in corrosion resistance and durability by sputtering, ion plating, CVD method etc. on the surface of an apparatus member (for example, refer patent document 2).

  However, with the recent rapid development of finer design rules for semiconductor devices and higher fineness in FPDs, there is a need for device members that further reduce particle generation.

Moreover, when the technique disclosed in Patent Document 1 is applied to a large member, there is a problem that it is difficult to ensure the uniformity of the finished surface. Furthermore, since the technique disclosed in Patent Document 2 requires a vacuum chamber for film formation processing, it is not suitable for application to a particularly large member, and the vacuum chamber itself is expensive. Furthermore, in the film forming method disclosed in Patent Document 2, since there is anisotropy in the film forming direction, it is difficult to form a film with a uniform thickness when the part shape is complicated. When there are a plurality of film formation surfaces and they cross each other, it is necessary to change the posture of the member after performing the film formation process on a predetermined surface, and perform film formation on another surface. There is also a problem in productivity.
JP 2006-237023 A (paragraph [0014], FIG. 1 etc.) JP-A-9-260471 (paragraph [0012], FIG. 1 etc.)

  This invention is made | formed in view of this situation, and it aims at providing the ceramic coating member which generation | occurrence | production of particle | grains was suppressed and which has the outstanding corrosion resistance and durability. It is another object of the present invention to provide a method for producing a ceramic coating member that makes it possible to easily form a ceramic film having a small number of particles and having excellent corrosion resistance and durability on a substrate having a complicated shape or a large substrate. And

  According to a first aspect of the present invention, a ceramic film having a purity of 98% or more, a film thickness of 0.05 μm or more and 10 μm or less, and an average particle diameter of 50 nm or less is formed on the substrate surface. A ceramic coating member is provided.

It is preferable that the average particle diameter d ₅₀ and 90% particle diameter d _{90 of the} ceramic film satisfy the relationship of d ₉₀ / d ₅₀ ≦ 10. In addition, as the base material, any one of metal, ceramics, glass, quartz, and a composite material composed of two or more materials selected from these is preferably used. It preferably contains an oxide, carbide or nitride of at least one element belonging to Group 6, 12 to 14 and rare earth elements.

According to the second aspect of the present invention, the coating film is formed on the surface of the substrate using a solution or dispersion containing at least one of metal alkoxides, organometallic complexes, oxide nanoparticles or non-oxide nanoparticles. A wet film forming step;
There is provided a method for producing a ceramic coating member, comprising: drying the coating film, and then heat-treating the coating film at a temperature of 300 ° C. to 1000 ° C. to form a ceramic film.

  Here, it is preferable to use any one of a spray method, a dip method, and an inkjet method for the wet film formation.

  In the ceramic coating member according to the present invention, generation of particles can be suppressed to an extremely low level. Thereby, for example, by using the ceramic coating member according to the present invention in a semiconductor manufacturing apparatus or an FPD manufacturing apparatus, it is possible to suppress the occurrence of defects or product defects in a semiconductor device or FPD that is a product. Moreover, if the method for manufacturing a ceramic coating member according to the present invention is used, a ceramic film having a uniform structure and film thickness can be formed with high productivity on a base material having a complicated shape or a large base material.

  The ceramic coating member according to the present invention has a structure in which a ceramic film having a purity of 98% or more, a film thickness of 0.05 μm or more and 10 μm or less, and an average particle diameter of 50 nm or less is formed on the surface of a predetermined substrate. ing.

  If the purity of this ceramic film is less than 98%, the impurities contained in this ceramic film will be the starting point of corrosion in a harsh usage environment such as a plasma atmosphere, a corrosive gas atmosphere, or a corrosive liquid atmosphere, resulting in a decrease in durability. As a result, particles are generated. Therefore, this ceramic coating member is not suitable for application to a semiconductor manufacturing apparatus or an FPD manufacturing apparatus, which is the main application. Moreover, the impurities contained as a component cause local abnormal grain growth, and particles are likely to be generated at that portion.

  Therefore, the purity of the ceramic film is preferably 99.5% or more, and more preferably 99.9% or more.

  The film thickness of the ceramic film is 0.05 μm or more and 10 μm or less. When the film thickness exceeds 10 μm, the interfacial strength (adhesion strength to the substrate (peel strength)) is lowered, and the risk that the ceramic film itself peels from the substrate and becomes particles is not preferable. The more preferable film thickness of the ceramic film is 5 μm or less, and it is more preferable that the film thickness is 1 μm or less. When the thickness of the ceramic film is less than 0.05 μm, the effect of reducing particles cannot be fully exhibited.

  The average particle size of the ceramic film is 50 nm or less. The average particle diameter of the ceramic film is obtained by analyzing an image (photograph) obtained by observing the surface of the ceramic film with an SEM. When this average particle diameter exceeds 50 nm, the interface strength of the ceramic film decreases, and the risk that the ceramic film itself peels off from the substrate and becomes particles is increased. A more preferable range of the average particle diameter of the ceramic film is 30 nm or less, and it is more preferable that the average particle diameter is 10 nm or less, and the decrease in the average particle diameter only increases the adhesion of the ceramic film to the substrate. In addition, since substantial grain boundary voids are reduced, excellent durability performance can be obtained even in harsh usage environments. Further, for example, when a ceramic coating member is used in a semiconductor manufacturing apparatus, even if particles are generated due to degranulation or the like, troubles such as short-circuiting a wiring of a semiconductor device as a product are less likely to occur.

It is preferable that the average particle diameter d ₅₀ (= 50% particle diameter) and the 90% particle diameter d _{90 of the} ceramic film satisfy a relationship of d ₉₀ / d ₅₀ ≦ 10. When this ratio exceeds 10, coarse particles are present in the fine particles constituting the ceramic film, so that the interfacial strength of the film is locally reduced, and degranulation occurs at that portion, and particles are easily generated. Become. This ratio is preferably 8 or less, and more preferably 6 or less.

Base materials constituting the ceramic coating member include metals such as aluminum (Al), iron (Fe), chromium (Cr), nickel (Ni) and alloys thereof (SUS), alumina (Al ₂ O ₃ ), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), ceramics such as aluminum nitride (AlN), glass, quartz (SiO ₂ ), and a composite material composed of two or more materials selected from these (for example, metal And a cermet material made of ceramics) is preferably used.

The ceramic film preferably contains an oxide, carbide or nitride of at least one element belonging to Groups 2-6, 12-14 and rare earth elements of the periodic table. Specifically, magnesium oxide (MgO ), Alumina (Al ₂ O ₃ ), aluminum nitride (AlN), silicon oxide (SiO ₂ ), silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), and yttria (Y ₂ O ₃ ). An appropriate material is selected depending on the use environment.

  The ceramic coating member described above is formed by wet-coating a coating film on a surface of a base material using a solution or dispersion containing at least one kind of metal alkoxide, organometallic complex, oxide nanoparticle or non-oxide nanoparticle. The coating film can be produced by a process in which the ceramic film is formed by drying and then heat-treating (baking) at a temperature of 300 ° C. or higher and 1000 ° C. or lower.

  Thus, a wet film forming method is used for forming the ceramic film. Vapor deposition, sputtering, ion plating, CVD, etc., which are a kind of ceramic film formation methods, are so-called dry film formation methods, but they are industrially disadvantageous because the film formation apparatus is expensive. In addition, since a vacuum chamber is required at the time of film formation, restrictions on film formation on a large base material are particularly large. Furthermore, when the substrate has a complicated shape such as having a concavely recessed inner surface, the film thickness distribution becomes non-uniform. For example, the film thickness is non-uniform when subjected to a thermal cycle by actual use. There arises a problem such that peeling occurs from an unfavorable part to form particles.

  On the other hand, in wet film formation, there are few restrictions on the structure of the film formation apparatus, and a coating film having a uniform thickness can be easily formed on a substrate having a complicated shape or a large substrate. There are advantages.

  As a wet film-forming raw material, a solution in which a ceramic fine powder, which is a metal alkoxide or organometallic complex that becomes a desired oxide, carbide, or nitride by heat treatment, or oxide, carbide, or nitride itself is dispersed in an organic solvent or the like (Sol) and a mixed solution in which a metal alkoxide or an organometallic complex is added to such a solution (sol) can be used.

  From the viewpoint of ensuring the purity of the finally formed ceramic film at 98% or higher, these raw materials are also set at 98% or higher. In the conventional wet film forming method, in order to promote the densification of the film, various additives such as alkali metals, heavy metals, and glass are mixed to reduce the firing temperature of the ceramic film. . However, alkali metals and heavy metals become impurities (contamination) for products such as semiconductor devices and FPDs and cause deterioration of product characteristics. Further, glass has low corrosion resistance and is not suitable as a member used in a semiconductor manufacturing apparatus or FPD manufacturing apparatus that requires high cleanliness. Further, in a ceramic film containing such an additive, local abnormal grain growth occurs due to the additive, and particles are likely to be generated in that portion. In the ceramic coating member according to the present invention, since a material having a purity of 98% or more is used as a wet film forming raw material for forming a ceramic film, occurrence of such a problem can be avoided.

  More specifically, as the wet film forming method, a spray method, a dip method, or an ink jet method is preferably used. The spray method is a method in which a film forming raw material solution is made into a mist and sprayed onto a substrate, and at this time, it is recommended to use a spray nozzle designed and optimized exclusively. However, the present invention is not limited to this, and a commercially available airbrush or spray gun can also be used. In the dip method, the base material is uniformly applied to the surface of the base material by dipping the base material in a film forming raw material solution and then pulling up the base material at a low speed (for example, 10 mm / min to 50 mm / min) and preferably at a constant speed This is a method of forming a film. The inkjet method is a method of forming a uniform coating film on the surface of a substrate by filling the inkjet head with a film forming raw material solution and relatively scanning the inkjet head and the substrate while applying a certain amount.

  When evaporating the solvent from the coating film formed in this way, in order to prevent the film formation state of the solid component from being disturbed by the generated vapor (for example, cracking or peeling), Perform under mild conditions that do not cause such disturbance. The coating film is solidified (gelled) by solvent evaporation.

  For baking the solidified coating film, a general atmospheric furnace or an atmospheric furnace can be used, but it is desirable to use a clean oven from the viewpoint of suppressing the introduction of impurities from the baking apparatus. The firing temperature is set to 300 ° C. or more and 1000 ° C. or less because if the firing temperature is less than 300 ° C., the chemical change from the solidified coating film to the crystallized ceramic film may be insufficient, There is a possibility that the ceramic particles are not sufficiently bonded to each other and the structure is likely to generate particles. On the other hand, if the firing temperature is higher than 1000 ° C., the sintering of the ceramic film proceeds, and grain growth that causes generation of particles tends to occur.

  When the desired ceramic film is an oxide, firing can be performed in an oxygen-containing atmosphere such as an air atmosphere. When forming a ceramic film of carbide, heating is performed in an inert atmosphere such as nitrogen or argon. In this case, it is preferable to use a film-forming raw material containing a large amount of carbon such as an alkyl group. When the nitride ceramic film is formed, firing in a nitrogen atmosphere is preferable, and a material containing nitrogen is preferably used as a raw material.

(Film forming member, base material, film forming raw material)
Tables 1 and 2 show various conditions of the film forming member, the base material, and the film forming method of the samples according to Examples and Comparative Examples, respectively.

  As the film forming member, a gas nozzle, a vacuum chuck, and an electrostatic chuck were taken up. The gas nozzle has an outer diameter of φ10 mm, an inner diameter of φ0.5 mm, and a structure provided with a screw at its end.

  The vacuum chuck has an outer diameter of φ300 mm, a plate thickness of 10 mm, ribs with a width of 2 mm are formed at φ285 mm and φ120 mm, respectively, and the area within φ285 mm accounts for 10% of the area area within φ285 mm In this structure, pins having a diameter of φ1.5 mm × 1 mm in height are formed at equal intervals, and further, eight suction vacuum holes are provided in a region within φ285 mm.

  The electrostatic chuck has an outer diameter of 300 mm and a plate thickness of 10 mm. A bipolar metal electrode is embedded in the electrostatic chuck, and the surface (substrate adsorption surface) occupies 10% of the area area within the 300 mm diameter. In which pins having a diameter of φ1.5 mm and a height of 20 μm are formed at equal intervals.

As shown in Table 1 and Table 2, as the base material constituting such a member, ceramics (Al ₂ O ₃ , AlN, Si ₃ N ₄ , SiC), glass, composite material (SiC / Al), metal (Al, stainless steel (SUS)) was used. Moreover, as a film-forming raw material for forming a ceramic film on the surface of these substrates, metal alkoxides, organometallic complexes, oxide nanoparticles / non-oxide nanoparticles having various elements shown in Table 1 and Table 2 are used. A sol (dispersion) containing one or two of the above was used.

(Production method)
A sol as a raw material was sprayed from a spray nozzle and sprayed onto the surface of the substrate to form a coating film having a predetermined thickness. Leave at room temperature until the solvent component of the sol is volatilized. Then, if the heat treatment temperature is 500 ° C. or lower, use a clean oven, and if it exceeds 500 ° C., heat treat using an electric furnace to form a ceramic film. Formed. When a ceramic film is formed on such a base material, a 20 mm substrate made of the same material as the base material is used as a sample for measuring the film thickness of the ceramic film formed under each film forming condition. The film was formed simultaneously with the substrate.

(Evaluation method and results)
The evaluation methods and the results are shown in Tables 1 and 2.

The ceramic film thickness measurement sample was broken at the center, and the cross section was observed with an FE-SEM (electrolytic emission electron microscope) to measure the ceramic film thickness. Further, observation by FE-SEM of ceramic membrane surface, the taken SEM photo by analyzing the image analyzer to calculate the mean particle size _{d 50} and 90% particle diameter _{d 90.}

  Measurement of surface particles (> 0.3 μm) of the gas nozzle was performed using a surface particle counter (SPC) QIII made by PENTAGON TECHNOLOGY. This device is connected to a probe (a groove is formed in a portion where air flows) in which two air (gas) pipes connected to the device main body are brought into contact with a portion where particles are measured. Clean air is supplied to the probe from the air piping and sprayed onto the sample surface. Particles generated there ride on the airflow from the probe, flow through another air piping to the device body, and are contained in the air by the device body. The amount of particles was measured, the size of the probe used was 0.5 inch, the air flow rate was 3.74 m / sec, and the measurement time (time for flowing air) was 3 seconds.

As a result, in the gas nozzles of Examples 1 to 19, it was confirmed that the number of particles was less than 5 particles / cm ² . On the other hand, all of the nozzles of Comparative Examples 1 to 5 exceeded 10 / cm ² .

  Moreover, the surface structure of the gas nozzle which concerns on Example 1 and Comparative Example 1 was observed by SEM. 1 and 2 show surface SEM photographs of gas nozzles according to Example 1 and Comparative Example 1, respectively. In contrast, in the gas nozzle of Example 1, a thin film is formed along the unevenness of the surface (the large particles that appear blurred in FIG. 1 are particles constituting the substrate), and finding the surface particles is It was extremely difficult. On the other hand, in the gas nozzle of Comparative Example 1, a large number of particles dropped out on the surface of the AlN that is the base material, and it was confirmed that a large number of particles were adhered to the degranulated portion.

Furthermore, in the gas nozzle, since the surface is activated by plasma exposure in the semiconductor manufacturing apparatus, particles are more likely to be generated than in the atmosphere. Therefore, the gas nozzles of Example 1 and Comparative Example 1 are further provided with HDP- Each of 36 CVD process chambers was mounted, and plasma was generated using SiH ₄ and O ₂ as process gases to form a SiO ₂ film with a thickness of 10 nm, and the wafer was sequentially examined.

  As a result, in the gas nozzle of Comparative Example 1, the number of particles exceeded 1000 when the number of processed wafers was 100. However, in the gas nozzle of Example 1, even when the number of processed wafers reaches 12,000, it is confirmed that the generation of particles is limited to 50 or less, and exhibits excellent corrosion resistance (environment resistance) and particle suppression performance. Was confirmed.

  The evaluation of the vacuum chuck and the electrostatic chuck is made by adsorbing a silicon wafer to each chuck with a predetermined adsorbing force, and calculating the number of particles (> 0.2 μm) adhering to the back surface of the silicon wafer as a wafer particle counter (WPC) (Topcon (Manufactured by WM-7C). Here, the size of the used silicon wafer is 5 inches, and an edge cut portion of 10 mm is formed.

  As a result, it was confirmed that 1000 to 4000 particles were detected in the chuck according to the comparative example, whereas the number of detected particles was reduced to about 100 in the chuck of the example. .

As described above, it was confirmed that the ceramic coating member according to the present invention exhibits an extremely excellent particle suppression effect.

  The ceramic coating member according to the present invention performs an electrostatic chuck or a vacuum chuck used for fixing a substrate, an arm for transporting the substrate, a film forming process or an etching process in a semiconductor manufacturing apparatus or an FPD manufacturing apparatus. It is suitable for a process gas / cleaning gas jet nozzle, a gas dispersion plate and the like.

A surface SEM photograph (Example 1) of a gas nozzle formed by forming an Al ₂ O ₃ film on the surface of an AlN substrate. Surface SEM photograph of gas nozzle made of AlN substrate (Comparative Example 1)

Claims (5)

  A ceramic coating member, wherein a ceramic film having a purity of 98% or more, a film thickness of 0.05 μm or more and 10 μm or less, and an average particle diameter of 50 nm or less is formed on a substrate surface. 2. The ceramic coating member according to claim 1, wherein a relationship of d ₉₀ / d ₅₀ ≦ 10 is established between an average particle diameter d ₅₀ and a 90% particle diameter d ₉₀ of the ceramic film. The base material is any one of metal, ceramics, glass, quartz, and a composite material composed of two or more materials selected from these,
The ceramic film includes an oxide, carbide or nitride of at least one element belonging to Groups 2-6, 12-14 and rare earth elements of the periodic table. The ceramic coating member according to 1. Forming a coating film on the surface of the substrate using a solution or dispersion containing at least one of metal alkoxide, organometallic complex, oxide nanoparticles or non-oxide nanoparticles;
And a step of forming a ceramic film by drying the coating film and then heat-treating the coating film at a temperature of 300 ° C. or higher and 1000 ° C. or lower.   The method for manufacturing a ceramic coating member according to claim 4, wherein the wet film formation is performed by any one of a spray method, a dip method, and an ink jet method.