JP5307476B2 - Surface-treated ceramic member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a surface-treated ceramic member and a method for manufacturing the same, and more specifically, for example, a member to be subjected to heat treatment in a semiconductor device manufacturing apparatus, a liquid crystal display manufacturing apparatus, a heating unit of a precision analytical instrument, or the like. Alternatively, the present invention relates to a surface-treated ceramic member suitable for use in a member exposed to a processing gas atmosphere plasma atmosphere or a vacuum atmosphere during heat treatment, and a method of manufacturing the same.

Ceramics having excellent corrosion resistance are used for members exposed to corrosive gases such as plasma chamber members for semiconductor device manufacturing apparatuses. This is because a material with poor corrosion resistance has a problem that the device life is short, and a reaction product with a corrosive gas adheres to the device as particles, which may cause deterioration of the quality of the device. For such applications, in addition to general ceramic materials such as alumina, materials having higher corrosion resistance such as AlN and Y ₂ O ₃ are used.

  However, changing the material alone does not completely prevent the particles. That is, since the ceramic member is a processed product of a brittle material, the surface layer always has recesses (pores, microcracks, processing flaws, etc.), but fine particles generated in the surface grinding process may enter the recesses. . It is difficult to completely remove such fine particles in the recess even after a normal cleaning process. In addition, micro cracks may occur during the manufacturing process of the ceramic member. When such fine particles and microcracks are exposed to a high temperature atmosphere, a processing gas atmosphere, a plasma atmosphere, a vacuum atmosphere during heat treatment, or the like, they are scattered as particles.

  Conventionally, several proposals have been made on methods for preventing scattering of particles of ceramic members.

  In Patent Document 1, “a method for cleaning a ceramic product, in which a solvent is applied to the surface to be cleaned of the ceramic product, and then a film made of a material soluble in the solvent is brought into contact with the surface to be cleaned, An invention relating to “a method for cleaning a ceramic product, wherein the surface to be cleaned is cleaned by peeling the film from the surface to be cleaned” is disclosed. In this invention, the contact portion of the film to the surface to be cleaned is melted by the solvent and follows the unevenness of the shape of the surface to be cleaned, so that the particles present on the surface to be cleaned are wrapped in the melted portion of the film. As a result, when the film is peeled off from the surface to be cleaned, particles are fixed on the contact surface side of the film and removed from the surface to be cleaned.

Patent Document 2 discloses that “99.2% by weight or more and 99.99% by weight or less of aluminum oxide and the balance is an oxide of a metal other than aluminum, the average particle diameter is 0.5 μm or more and 15 μm or less, and A sintered body having a density of 3.88 g / cm ³ or more and 3.97 g / cm ³ or less, or a sintered sintered body at a temperature of 1000 ° C. or more and 1550 ° C. or less for 0.1 hour or more, An invention relating to an “alumina ceramic sintered body characterized by being heat-treated for 6 hours or less” is disclosed.

  Further, as a method for improving the corrosion resistance of ceramic materials, an invention has been proposed in which a coating having high corrosion resistance is formed mainly for sprayed ceramics.

  Patent Document 3 states that “a corrosion-resistant composite member used in a halogen-based corrosive gas environment or in a plasma environment of a halogen-based corrosive gas, the base material and at least a halogen-based corrosive gas or a halogen-based corrosive gas on the base material. And a coating formed of a ceramic sol / gel provided at a portion exposed to the plasma of the above, an invention relating to a “corrosion resistant composite member” is disclosed.

  Patent Document 4 states that “a single metal, alloy, cermet, or ceramic is sprayed on the surface of a base material that has been pre-processed for thermal spraying, and then a sealed material is formed in the pores in the thermal spray coating. After applying or impregnating the pore liquid, performing aging or heat treatment and sealing treatment, a solution in which the vitreous forming component is dissolved or suspended is applied by brushing or spraying, and dried at room temperature or at a temperature of 900 ° C. or lower. An invention relating to “a method of forming a composite film having corrosion resistance, characterized by forming a glassy surface film by firing and having a long-term use” is disclosed.

  Patent Document 5 states that “a composite coating material provided on a ceramic member, comprising: a ceramic porous body having open pores; and a resin impregnated in the open pores. The invention relating to “material” is disclosed, and in the examples, only the ceramic porous body formed by the thermal spraying method is described.

  In Patent Document 6, “a ceramic insulating layer obtained by thermal spraying is made of a thermosetting resin at the entrance of pores generated in the ceramic insulating layer by utilizing the difference in shrinkage due to the temperature difference between the gas and the resin. An invention relating to a “sealing treated ceramic insulating layer characterized in that a sealing body is formed” is described.

JP-A-11-21187 JP-A-8-81258 JP 2003-335589 A JP2001-152307 JP2003-119087 JP 2002-180233 A

  In the invention described in Patent Document 1, a film is formed on the surface of the ceramic and the fine particles that cause particles are removed by peeling the film from the surface to be cleaned. It is difficult to remove fine particles.

  In the invention described in Patent Document 2, microcracks that cause particles are repaired by heat treatment at 1000 to 1550 ° C., but the fine particles that enter the grain boundaries and pores cannot be removed.

  The inventions described in Patent Documents 3 to 6 are all for the purpose of forming a film on thermal sprayed ceramics, and do not solve the problem of particles in the first place. Moreover, since patent documents 3 to 5 form a film on the entire surface of the ceramic surface, the function of the ceramic cannot be exhibited.

  In order to solve the above problems, the present inventors conducted extensive research on a method for permanently preventing the generation of particles while maintaining the excellent corrosion resistance of the ceramic sintered body. Got.

  (A) If the entire surface of the ceramic sintered body is covered with a film, the function inherent to the ceramic sintered body cannot be exhibited, and the function as a corrosion-resistant member depends on the performance of the film. Further, in the case of full-surface coating, there is a problem of durability such as peeling. Therefore, it is desirable to have a configuration that does not cover the entire surface of the ceramic sintered body (the entire surface in contact with the processing atmosphere).

  (B) One of the causes of generation of particles is due to scattering of ceramic fine particles generated during firing or grinding. That is, the ceramic fine particles scattered in the firing furnace and the ceramic fine particles generated during the grinding process adhere to the surface of the ceramic sintered body, but even if various conventionally known cleaning methods such as ultrasonic cleaning are used. It is difficult to completely remove the fine particles that have entered the gaps between the crystal grain boundaries, the micropores, the processing flaws, and the like. Therefore, it is necessary to fix the ceramic fine particles in the minute space instead of removing the ceramic fine particles remaining in the minute space.

  (C) Another cause of the generation of particles is that microscopic pieces generated by microcracks generated in the ceramic member fall off during operation of the apparatus. Therefore, it is necessary that a fixing material for preventing the micro-pieces from dropping off due to micro cracks is present on the surface of the ceramic member.

  The present invention has been made on the basis of the above knowledge, and an object of the present invention is to provide a ceramic member that exhibits the function originally possessed by a ceramic sintered body and that does not cause particle scattering and a method for manufacturing the same.

The present invention is summarized as a method for producing a surface-treated ceramic member and Table surfaces treated ceramic member shown below SL.

(1) A ceramic member having a film-forming surface on at least a part of a ceramic sintered body substrate having a porosity of 1% or less, wherein the film-forming surface is composed of a sol-gel film, a resin film, or a composite film thereof. Film (excluding a film consisting only of a sol-gel film of a silicon alkoxide compound polymer) and the substrate surface, and the area ratio of the film is 5 to 80% of the entire film-forming surface, A surface-treated ceramic member in which concave portions on the surface of the bonded body are selectively covered with a film.

  (2) The surface-treated ceramic member according to (1), wherein the area ratio of the film is 5 to 80% of the entire surface-treated surface.

(2) The surface-treated ceramic member according to (1) , wherein the sol-gel film is composed of a metal alkoxide compound polymer.

(3) The surface-treated ceramic member according to either (1) or (2) , wherein the resin film is composed of a resin composition having a glass transition point of 100 ° C. or higher.

(4) The surface-treated ceramic member according to any one of (1) to (3) , which is used in a semiconductor or electronic device manufacturing apparatus.

(5) Coating material composed of a sol-gel film, a resin film, or a composite film thereof on the surface of a ceramic sintered body base with a porosity of 1% or less (excluding a coating material consisting only of a sol-gel film of a silicon alkoxide compound polymer) .) Is applied, and the film material before curing is left in the recesses on the surface of the ceramic sintered body so that the area ratio of the film becomes 5 to 80% of the entire film forming surface. A method for producing a surface-treated ceramic member, comprising removing the portion and curing the coating material remaining in the concave portion on the surface of the ceramic sintered body.

(6) The method for producing a surface-treated ceramic member according to (5) , wherein part of the coating material is removed by wiping.

  According to the present invention, the ceramic sintered body originally has the function, that is, exhibits excellent corrosion resistance, occurs during sintering, grinding, etc., and is formed in a minute space such as a pore on the surface of the ceramic sintered body. It is possible to prevent scattering of particles generated due to the remaining fine particles or microcracks.

1. Ceramic sintered body As the ceramic sintered body, in order to express the original chemically stable function, a ceramic sintered body having a fine structure with a porosity of 1% or less is used. This is because if the porosity exceeds 1%, the mechanical properties and corrosion resistance deteriorate. Further, in the case of a ceramic sprayed coating, it is more porous than a sintered body that is densely sintered, and has a low mechanical strength and a large specific surface area, and therefore has poor corrosion resistance. For this reason, since it is a material which easily generates particles due to degranulation, it cannot be used for the surface-treated ceramic member of the present invention.

  The ceramic material used in the present invention is not particularly limited, and general ceramic materials such as alumina, yttria, zirconia, mullite, cordierite, silicon carbide, silicon nitride, aluminum nitride, and sialon can be used. Among these, it is particularly desirable to use alumina, aluminum nitride, yttria, etc., which are excellent in corrosion resistance and heat resistance.

  There is no restriction | limiting in particular in the manufacturing method of a ceramic sintered compact, What is necessary is just to employ | adopt a general manufacturing method. For example, after adding a known molding binder to a powder raw material having an average particle diameter of about 0.01 to 1 μm and granulating it by a known method such as a spray drying method, a die press, CIP (cold isostatic pressing) ) Can be produced by firing. A known sintering aid may be added to the powder raw material as necessary. At this time, an atmospheric furnace can be used as long as it is an oxide-based ceramic. For non-oxide ceramics, an atmosphere firing furnace such as nitrogen or argon can be used in addition to a vacuum furnace.

2. Film Material The surface-treated ceramic member of the present invention is obtained by forming a film on the surface of the ceramic sintered body. As the coating material, for example, an organic resin solution of an oxide suspension, a chromic acid solution, an inorganic colloidal solution, and the like can be used. In these coating materials, the dense ceramic sintered material used in the present invention is used. Once applied to the body, it is difficult to completely prevent particles. In addition, if the resin solution does not contain solids, it can be easily applied, wiped off, and cured. For example, polystyrene can be easily dissolved in an organic solvent such as acetone, but the heat resistance of the film itself is low. Since it is inferior, it is easy to drop off in an environment where the operating temperature of the apparatus is 100 ° C or higher. Therefore, it is desirable to use a heat-resistant resin solution that does not contain solids.
As the film material used in the present invention, it is more desirable to use sol-gel, resin or a mixed material thereof. This is because these materials are liquid at room temperature, and then cured by condensation polymerization, hydrolysis reaction, or the like, and exist stably at the operating temperature (100 ° C. or higher) in a device processing apparatus such as sputtering.

  As the sol-gel film, it is desirable to use a compound that forms a metal oxide by curing an Al, Zr, Ti, Y-based alkoxide compound by hydrolysis. Moreover, it is good also as a composite film of these and Si type | system | group alkoxide compounds. This is because these alkoxide compounds are easily cured at room temperature and have a melting point far exceeding 150 ° C., which is the upper limit of the use temperature, and thus exist stably during operation. The sol-gel film is simple in that a film can be formed using a solution.

  As the resin film, it is desirable to use a resin that is cured at room temperature or by heating, such as polyimide resin, phenol resin, epoxy resin, fluororesin, or silicon resin. In particular, it is desirable to be composed of a polymer having a glass transition point of 100 ° C. or higher. This is to provide heat resistance that can withstand the heat load during use of the device processing apparatus. Since polyimide resins, epoxy resins, fluororesins, etc. are almost insoluble in solvents and difficult to liquefy, apply precursor solutions, heat cure, add curing agents, etc., cure with time by UV irradiation, moisture absorption It is preferable to employ a method of curing by allowing the crosslinking / polymerization reaction to proceed. This is because the precursor is unpolymerized and has a low molecular weight, so that it can be easily dissolved in a solvent. Further, in the case of a resin that is heated and melted, it may be applied in the form of a suspension / colloid solution in which fine powder of a resin body is dispersed, wiped off, and then formed into a film by warm welding.

  Specifically, with a polyimide resin, an aromatic precursor may be cured by heating, and with a phenol resin, a phenolic compound, formaldehyde, or the like may be cured by heating. Moreover, in the case of an epoxy resin, it is a precursor and it is good to mix the low molecular epoxy compound which raise | generates a polymerization reaction by mixing, and an amine compound, and to apply | coat and wipe off before hardening. For the epoxy resin, a photo-curing material that allows the crosslinking / curing reaction to proceed by irradiation with ultraviolet rays or the like may be selected. In the case of a fluororesin, it is preferable to use a finely powdered resin body, apply this suspension, wipe off, and then heat to a temperature capable of welding to form a film.

  The above film is selectively embedded in recesses (clearance of crystal grain boundaries, micropores, processing flaws, etc.) existing on the surface of ceramic sintered body exposed to the processing atmosphere in at least semiconductor manufacturing equipment, etc. In this part, the ceramic sintered body is formed to be exposed, and the surface of the ceramic sintered body needs to be mixed with the surface of the ceramic sintered body substrate and the surface of the film. Here, the processing atmosphere includes a processing gas atmosphere (such as a corrosive gas such as argon gas, hydrogen gas, and halogen), a plasma atmosphere, and a vacuum atmosphere during heat treatment.

  This is because, as described above, fine particles or the like remain in the concave portions of the ceramic sintered body, and microcracks may be formed in the firing step, the processing step, or the like. The above-mentioned film selectively covers the recesses, captures the fine particles present therein, prevents scattering, and also plays a role of preventing the falling off of the fine pieces caused by the microcracks. On the other hand, the ceramic sintered body excellent in corrosion resistance is exposed. The surface on which this ceramic sintered body is exposed is a smooth part that is originally free of dents. Therefore, it is easy to remove fine particles by washing, etc., and particles are not easily generated. It is a part that should exhibit its original function.

  The area ratio of the coating on the treated surface of the ceramic sintered body desirably occupies 5 to 80% of the entire surface treated surface. That is, when the area ratio of the film is less than 5%, the effect of capturing the above-mentioned fine particles and the like is insufficient, and the scattering of the particles may not be prevented. On the other hand, when the area ratio exceeds 80%, the ceramics There is a possibility that the original function of the sintered body cannot be exhibited.

The area ratio of the film can be determined by the following method.
(1) Mapping the distribution ratio of the main element derived from the coating material (for example, in the case of polyimide resin, the main element is C) with a wavelength dispersion type electronic probe microanalyzer (EPMA) at any part of the surface-treated ceramic member To do.
(2) The distribution ratio of the main element derived from the ceramic substrate (for example, in the case of alumina, the main element is Al) is mapped by the same method as in (1) above, and it is confirmed that there is a complementary relationship. To do.
(3) From the detected X-ray detection intensity and the area ratio, the area ratio of the main element derived from the film material is obtained and this is used as the area ratio of the film. Specifically, in order to exclude the influence of noise due to X-ray scattering and surface properties, the X-ray detection intensity is divided into two categories using a value that is 0.20 times the maximum value of the X-ray detection intensity as a threshold value. The area ratio in the region where the line detection intensity is equal to or greater than the threshold is defined as the area ratio of the film.

  In the case where it is difficult to discriminate the coverage with EPMA, for example, the constituent elements of the surface-treated ceramic member and the covering material are similar, micro-Raman spectroscopy is suitable as an investigation means for complementing EPMA. Raman spectroscopy can detect differences in the chemical bonding state of materials and make it possible to distinguish between ceramics and coating materials.

  In order to mix the substrate surface and the coating surface on the treated surface, it is useful to apply the coating material described above to the ceramic sintered body, wipe it with a waste cloth, etc., dry and cure it before it completely cures. is there. This operation is effective even once, but it is more desirable to perform this operation twice or more. The substrate surface may be a ground surface, a fired surface, a heat-treated surface, a blast surface, or the like.

  Here, the coating liquid can be easily removed on a relatively smooth surface (fine particles do not easily remain on this surface), but the coating liquid remains in the recesses (pores, etc.), and this is dried and cured. Thus, the concave portion of the ceramic sintered body is covered. Since the film formed in the recess is firmly covered by the anchor effect, there is no fear of dropping off.

  Various ceramic substrates (surface roughness Ra: 0.7 ± 0.1 μm, dimensions: 30 mm × 30 mm × 2.5 mm) having the compositions and porosity listed in Table 1 were prepared, and the coating films shown in Table 1 were prepared on these ceramic substrates. A test piece was prepared by applying the material and wiping with a waste cloth. For various test pieces, the area ratio of the coating and the number of particles generated were determined. Moreover, about some Examples, it shape | molded in the shape of the ceramic chamber components of a semiconductor manufacturing apparatus, and mounted in the apparatus, and the use condition was investigated.

<Area ratio of film>
Using a sputter deposition apparatus for SEM testing (Sanyu Denshi, SC-704), gold was vapor-deposited on the test piece in advance to form a conductive film. The SEM image and the distribution of the element derived from the substrate and the element derived from the coating material were scanned and displayed in a map according to the conditions of the visual field and the acceleration voltage of 15 kV. Thereby, it confirmed that distribution of the element derived from a base material and the element derived from a film | membrane material had a complementary relationship. Thereafter, the detected value of 0.20 times the maximum value of the detected X-ray intensity was divided into two categories as threshold values, and the area ratio in the region where the detected X-ray intensity was equal to or greater than the threshold value was defined as the film area ratio.

<Number of particles>
Each test piece is inserted into a beaker containing pure water, and the beaker is mounted in a tank equipped with an ultrasonic transmitter, and then ultrasonic waves of 104 kHz are loaded for 1 minute at room temperature, The number of particles scattered in water was measured with a liquid particle counter (measurement range: 0.5 to 20 μm), and the number of particles of 1 μm or more is shown in Table 1.

In addition, the glass transition point of each resin used in the Example was as follows.
Epoxy resin: 180 ° C
Polyimide resin: 280 ° C
Fluororesin: 250 ° C
Polystyrene resin: 80 ° C
Phenolic resin: 150 ° C

  As shown in Table 1, in Examples 1 to 7 of the present invention, the number of particles was as good as 20 to 53 particles / ml. However, Example 4 of the present invention using polystyrene resin as the coating material had a glass transition temperature as low as 80 ° C., and therefore, when used for a long time as a chamber part of a semiconductor manufacturing apparatus, it thermally deteriorated and the number of particles increased. Hereinafter, a method for obtaining the area ratio of the film from the distribution of the elements derived from the SEM image, the base material-derived element and the film-derived element of the invention example 2 will be described in detail.

  FIG. 1 shows the SEM image of Example 2 of the present invention and the distribution based on the maximum value of the X-ray detection intensity of Al (element derived from the base material) and C (element derived from the film), and FIG. The SEM image of Example 2 of this invention and the distribution of Si (element derived from a film) divided into two sections according to the above-described method are shown. In the figure, SL is an SEM image, C is a C distribution, and Al is an Al distribution. 1 and 2, the SEM image and Al and C distribution maps correspond to each other at the same site and 1: 1, and thus can be superimposed.

  As shown in FIG. 1, in Example 2 of the present invention, it can be seen that Al and C are in a complementary relationship, and the substrate surface and the coating surface are mixed. In addition, as shown in FIG. 2, the maximum value of the X-ray detection intensity in the C distribution is 1200, and the X-ray detection intensity is equal to or greater than the threshold when 240, which is 0.20 times, is divided into two categories. The area ratio (area ratio of the film) in the region to be 43.7%.

  On the other hand, Comparative Examples 1 and 2 were examples in which no film was formed, and the number of particles was large. Further, in Comparative Example 3 in which a film was formed on the entire surface, although the initial number of particles was small, peeling occurred when used as a chamber part of a semiconductor manufacturing apparatus for 2 hours, and the number of particles increased rapidly. Comparative Examples 4 to 6 all use thermal sprayed ceramics as the base material, but all have a high porosity, and even when a film is formed, the number of particles has not been reduced.

  According to the present invention, the ceramic sintered body originally has a function, that is, excellent corrosion resistance, occurs during firing, grinding, etc., and remains in a minute space such as a pore on the surface of the ceramic sintered body. Scattering of particles generated due to the generated fine particles or microcracks can be prevented. Therefore, the surface-treated ceramic member of the present invention is optimally used for a member exposed to a high temperature atmosphere, a corrosive gas atmosphere, or a plasma atmosphere in, for example, a semiconductor device manufacturing apparatus, a liquid crystal display manufacturing apparatus, and the like.

SEM image of Invention Example 2 and distribution of Al (element derived from base material) and C (element derived from film) SEM image of Invention Example 2 and distribution of C (element derived from film) divided into two according to the above method

Claims (6)

A ceramic member having a film-forming surface on at least a part of a ceramic sintered body substrate having a porosity of 1% or less,
Film-forming surface, sol-gel film, (except sol-gel film consisting only film of silicon alkoxide compound polymer.) Resin film, or a composite film composed of the film and the substrate surface is mixed, the film A surface-treated ceramic member having an area ratio of 5 to 80% of the entire film-forming surface, wherein the concave portion of the surface of the ceramic sintered body is selectively covered with a film. The surface-treated ceramic member according to claim 1 , wherein the sol-gel film is composed of a metal alkoxide compound polymer. The surface-treated ceramic member according to claim 1 or 2 , wherein the resin film is composed of a resin composition having a glass transition point of 100 ° C or higher. Surface treatment ceramics member according to any one of claims 1 to 3, characterized in that for use in the semiconductor or electronic device manufacturing apparatus. A coating material composed of a sol-gel film, a resin film, or a composite film thereof (excluding a coating material composed only of a sol-gel film of a silicon alkoxide compound polymer) on the surface of a ceramic sintered body substrate having a porosity of 1% or less. After coating, a part of the coating material is removed so that the area ratio of the coating is 5 to 80% of the entire coating forming surface under the condition that the coating material before curing remains in the concave portion of the ceramic sintered body surface. And curing the film material remaining in the recesses on the surface of the ceramic sintered body. The method for producing a surface-treated ceramic member according to claim 5 , wherein part of the coating material is removed by wiping.

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