Film deposition apparatus and method for manufacturing ceramic films

Abstract

To provide a film deposition apparatus capable of enhancing an adhesion efficiency of ceramic raw material powder.SOLUTION: A film deposition apparatus includes an aerosol generator 6, a nozzle 10, transfer gas supply means 15 having a transfer gas supply tube S2, accelerated gas supply means 20 having an accelerated gas supply tube S3, and heating means 23. The transfer gas supply tube S2 is connected to the nozzle 10 such that an ejection edge thereof is located in the nozzle 10 and a flow line of transfer gas ejected from the ejection edge has a linear shape up to the ejection edge of the nozzle 10. The accelerated gas supply tube S3 is connected to the nozzle 10 such that an ejection edge thereof is located in the vicinity of the ejection edge of the transfer gas supply tube S2 in the nozzle 10 and a flow line of accelerated gas ejected from the ejection edge collides the flow line of transfer gas.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a film forming apparatus for forming a film on a substrate and a method for manufacturing a ceramic film using the same.

Background Art

[0002] As a method of forming a thick film made of a metal oxide material on a substrate without undergoing heat treatment at a high temperature such as sintering, there is a technique called an aerosol deposition method (AD method). In this AD method, a raw material powder composed of fine particles such as metal oxides is jetted from a nozzle toward a substrate such as ceramics or plastic at about the speed of sound, and the fine particles are crushed and deformed by the energy when the raw material powder collides with the substrate, thereby forming a dense film on the substrate.

[0003] For example, in the method described in Patent Document 1, by using non-spherical amorphous brittle material fine particles with an average particle diameter of 50 nm or more and 1 μm or less as the raw material powder, a film having a dense and strong bond can be formed.

[0004] Also, in this type of AD method, it is known as a practical problem that the ratio of the weight of the raw material powder formed as a dense film to the feeding weight of the raw material powder per unit time (also referred to as the adhesion efficiency) is low.

[0005] In Patent Document 2, a method of making the temperature at the tip of the nozzle higher than the temperature of the aerosol introduced into the nozzle has been proposed in order to improve the adhesion efficiency, and according to this method, it is said that the formation speed can be improved.

[0006] On the other hand, similar to the AD method, as a method of forming a dense film on a substrate by jetting a raw material powder from a nozzle toward the substrate, there is a technique called a cold spray method as disclosed in Patent Document 3.

[0007] In a cold spray apparatus used in the cold spray method, the high-pressure gas supplied from the gas source branches into two paths. The high-pressure gas flowing through one path is heated to a temperature above room temperature and below the melting point or softening temperature of the raw material powder via a gas heater, and then supplied to the working gas supply port. The high-pressure gas flowing through the other path is supplied to a powder supply device and is supplied to the powder supply port along with the raw material powder as a carrier gas. The high-pressure gas supplied from the working gas supply port to the nozzle inlet expands, decreases in pressure and increases in velocity as it passes through the tip and throat to the tip, eventually becoming a supersonic flow. As this supersonic flow of high-pressure gas is being delivered linearly towards the nozzle outlet, the raw material powder is supplied from the powder supply port along with the carrier gas, and the raw material powder is ejected from the nozzle outlet along with the supersonic flow of high-pressure gas (see Patent Document 3).

[0008] Generally, the raw material powders used in the cold spray method are often metals or alloys such as Zn, Cu, Al, Cr, Ni, Mo, Fe, Nb, and Ti. However, for example, Patent Document 4 discloses a method for forming a ceramic film by the cold spray method using ceramic raw material powder. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2013-73855 [Patent Document 2] Patent No. 3812660 [Patent Document 3] Patent No. 4310251 [Patent Document 4] Patent No. 5345419 [Overview of the project] [Problems that the invention aims to solve]

[0010] Patent Document 2 states that by controlling the heating means so that the temperature at the nozzle tip is 50 to 150°C, the film formation rate can be improved by making the temperature at the nozzle tip higher than the temperature of the aerosol introduced into the nozzle. However, simply raising the temperature at the nozzle tip to around 50 to 150°C does not sufficiently improve the formation rate compared to the case without heating, and coupled with the low yield of the raw material powder, it is not possible to achieve a practically sufficient adhesion efficiency.

[0011] Furthermore, in the cold spray method, the raw material powder is supplied along the way as the supersonic high-pressure gas is delivered linearly towards the nozzle outlet. As a result, the dispersibility of the raw material powder in the supersonic high-pressure gas becomes a problem, and there is room for improvement in the uniformity of the film structure. In addition, depending on the raw material powder, the effect of the particles themselves scraping off parts of already formed films (blast effect) outweighs the effect of the raw material powder itself accumulating, making it difficult to obtain practical adhesion efficiency.

[0012] This invention has been made in view of the above circumstances, and aims to provide a film-forming apparatus that can improve the adhesion efficiency of ceramic raw material powder, and a method for manufacturing a ceramic film using this film-forming apparatus. [Means for solving the problem]

[0013] The characteristic configuration of the film deposition apparatus according to the present invention for achieving the above objective is as follows: A processing chamber having a holding section for holding the substrate, and whose interior is reduced to a predetermined pressure or below, An aerosol generating unit that generates an aerosol in which ceramic raw material powder with an adjusted primary particle size distribution is dispersed, A nozzle is disposed in the processing chamber such that its ejection end faces the holding portion, A conveying gas supply means having a conveying gas supply pipe connected to the nozzle, which supplies the conveying gas to the ejection end of the nozzle via the aerosol generating unit, The acceleration gas supply means includes an acceleration gas supply pipe connected to the nozzle, and supplies the acceleration gas so as to merge with the transport gas flowing inside the nozzle, The acceleration gas supply pipe is provided with a heating means for heating the acceleration gas flowing through the acceleration gas supply pipe, The aforementioned conveying gas supply pipe is connected to the nozzle such that its ejection end is located inside the nozzle, and the streamline of the conveying gas ejected from the ejection end is straight to the ejection end of the nozzle. The accelerating gas supply pipe is connected to the nozzle such that its ejection end is located near the ejection end of the transport gas supply pipe within the nozzle, and the streamlines of the accelerating gas ejected from the ejection end collide with the streamlines of the transport gas. The distance from the connection point with the nozzle in the accelerating gas supply pipe to the ejection end of the nozzle is 20 mm or more. the law of nature, The distance Ib from the end of the nozzle opposite to the ejection end to the connection point with the nozzle in the accelerating gas supply pipe, and the distance Ic from the end of the nozzle opposite to the ejection end to the transport gas supply pipe, are configured such that the inner diameter of the accelerating gas supply pipe satisfies the following equation, with respect to the inner diameter Da. Film deposition equipment. Ib-Da≦Ic≦Ib+Da

[0014] According to the above-described configuration, the streamlines of the accelerating gas ejected from the nozzle end of the accelerating gas supply pipe collide with the streamlines of the transport gas. This allows for acceleration of the ceramic raw material powder in a speed range that could not be achieved with conventional AD methods, thereby improving the flight speed of the ceramic raw material powder. As a result, the amount of ceramic raw material powder that forms a dense film can be increased. Furthermore, by connecting the conveying gas supply pipe to the nozzle in such a way that the streamline of the conveying gas ejected from its outlet is straight from the nozzle's outlet to the nozzle's outlet, it is possible to suppress uneven concentration of ceramic raw material powder within the nozzle's flow path cross-section, thereby suppressing adhesion of ceramic raw material powder to the inner wall surface of the nozzle. Furthermore, by controlling the flow rate and pressure of the accelerating gas supplied by the accelerating gas supply means, the flight speed of the ceramic raw material powder after acceleration can be adjusted. Furthermore, when the distance from the connection part of the acceleration gas supply pipe to the nozzle to the ejection end of the nozzle is 20 mm or more, the energy of the acceleration gas is easily transmitted to the ceramic raw material powder, and the flying speed of the ceramic raw material powder can be improved. Therefore, the film quality can be improved. Furthermore, the film quality can be improved by configuring the distance Ib from the end of the nozzle opposite the ejection end to the connection point with the nozzle in the accelerating gas supply pipe, and the distance Ic from the end of the nozzle opposite the ejection end to the ejection end of the transport gas supply pipe, such that Ib-Da≦Ic≦Ib+Da, where Da is the inner diameter of the accelerating gas supply pipe. Therefore, according to the film forming apparatus having the above characteristic configuration, while suppressing the adhesion of the ceramic raw material powder to the inner wall surface of the nozzle, the amount of the ceramic raw material powder formed as a dense film can be increased, so that the adhesion efficiency of the ceramic raw material powder can be increased. Furthermore, since the flying speed of the ceramic raw material powder can be adjusted by making the energy of the acceleration gas easily transmitted to the ceramic raw material powder, the density of the film can be controlled according to the use of the film.

[0015] Moreover, a further characteristic configuration of the film forming apparatus according to the present invention is that the acceleration gas supply means supplies the acceleration gas so that the pressure in the acceleration gas supply pipe becomes 400 kPaG or more.

[0016] The inventor of the present application has found that when the pressure in the acceleration gas supply pipe is 400 kPaG or more, the adhesion efficiency can be particularly improved. That is, according to the above characteristic configuration, the flow rate of the acceleration gas in the vicinity of the confluence part with the carrier gas in the nozzle can be increased to a speed range that can accelerate the ceramic raw material powder to a flying speed at which the adhesion efficiency is sufficiently improved, so that the adhesion efficiency can be improved.

[0017] Moreover, a further characteristic configuration of the film forming apparatus according to the present invention is that an orifice portion is formed between the ejection end of the acceleration gas supply pipe and the heating means in the acceleration gas supply pipe.

[0018] According to the above characteristic configuration, without increasing the flow rate of the accelerating gas flowing through the accelerating gas supply pipe, the flow velocity of the accelerating gas in the expansion part passing through the orifice part can be increased. Therefore, the ceramic raw material powder can be accelerated in a higher speed range, and the flying speed of the ceramic raw material powder can be further improved. Thus, the amount of the ceramic raw material powder formed as a dense film can be further increased, and the adhesion efficiency can be further improved.

[0019] Moreover, a further characteristic configuration of the film forming apparatus according to the present invention is that the accelerating gas supply means supplies the accelerating gas so that the pressure in the accelerating gas supply pipe on the upstream side of the orifice part becomes 600 kPaG or more.

[0020] According to the above characteristic configuration, the flow velocity of the accelerating gas in the expansion region passing through the orifice part can exceed the speed of sound. Therefore, the ceramic raw material powder can be accelerated in an ultra-high speed range that could not be achieved by the conventional AD method, the flying speed of the ceramic raw material powder can be improved, and the adhesion efficiency can be further improved.

[0021] Moreover, a further characteristic configuration of the film forming apparatus according to the present invention is that the heating means heats the accelerating gas flowing through the accelerating gas supply pipe so that the gas temperature at the ejection end of the nozzle is 300°C or more and less than 700°C.

[0022] When the gas temperature at the ejection end of the nozzle is less than 300°C, it is somewhat insufficient in terms of increasing the energy when the ceramic raw material powder collides to improve the adhesion efficiency. When it is 700°C or more, there is a risk that the porous region in the formed film becomes large and the strength of the film is insufficient, resulting in the problem of film peeling. However, according to the above characteristic configuration, the energy when the ceramic raw material powder collides can be made sufficiently large, and the adhesion efficiency can be improved.

[0023] The characteristic configuration of the method for producing a ceramic film according to the present invention, which achieves the above objective, is that the ceramic film is produced using the above-mentioned film-forming apparatus, with the ceramic raw material powder having been prepared so that the primary particles of 5 μm or larger account for less than 4% by volume.

[0024] If the particle size distribution of primary particles is such that primary particles of 5 μm or larger account for 4% or more by volume, blasting by the ceramic raw material powder may occur, preventing film formation or achieving sufficient adhesion efficiency. However, with the above-described characteristic configuration, it is possible to manufacture ceramic films while achieving sufficient adhesion efficiency.

[0025] Furthermore, a characteristic feature of the method for manufacturing a ceramic film according to the present invention is that a stabilized zirconia is used as the ceramic raw material powder, and the ceramic film is manufactured using the above-mentioned film deposition apparatus.

[0026] The inventors of this application have experimentally confirmed that when a ceramic film is manufactured using stabilized zirconia as a ceramic raw material powder with an adjusted primary particle size distribution, a significant improvement in adhesion efficiency is observed. [Brief explanation of the drawing]

[0027] [Figure 1] This figure shows the configuration of the film deposition apparatus according to this embodiment. [Figure 2] This diagram illustrates the positional relationships of the various parts in the film deposition apparatus according to this embodiment. [Modes for carrying out the invention]

[0028] The following describes a film deposition apparatus 1 according to one embodiment of the present invention with reference to the drawings.

[0029] [About the film deposition equipment] As shown in Figure 1, the film deposition apparatus 1 according to this embodiment includes a processing chamber 2, an aerosol generating unit 6, a nozzle 10, a conveying gas supply means 15, an accelerating gas supply means 20, and a heater 23 as a heating means.

[0030] Processing chamber 2 is an airtight enclosure. The pressure inside processing chamber 2 is reduced to a predetermined pressure (for example, about 0.5 kPa) or less by exhausting gas using a mechanical booster pump 3 and a vacuum pump 4, which serve as exhaust equipment. A holding section 5 for holding the substrate K to be subjected to film deposition and a nozzle 10 are also arranged inside processing chamber 2.

[0031] The aerosol generation unit 6 is a device that generates an aerosol in which ceramic raw material powder, whose primary particle size distribution has been adjusted, is dispersed. In this embodiment, the raw material powder supply unit 7 is connected to the aerosol generation unit 6 via a raw material supply pipe S1. A nozzle 10 is also connected to the aerosol generation unit 6 via a conveying gas supply pipe S2, which will be described later. In the aerosol generation unit 6, an aerosol is generated by mixing the ceramic raw material powder supplied at a constant rate from the raw material powder supply unit 7 with the conveying gas supplied by the conveying gas supply means 15. This generated aerosol is supplied to the nozzle 10 through the conveying gas supply pipe S2. The supply rate of ceramic raw material powder supplied from the raw material powder supply unit 7 to the aerosol generation unit 6 can be increased to shorten the time required to form a film with the target thickness, but if the supply rate is too high, pulsation will occur in the amount of raw material powder supplied, making it difficult to obtain a homogeneous film. On the other hand, if the supply rate is too low, the film quality will be improved, but the time required to complete film formation will be longer, increasing manufacturing costs. Therefore, the supply rate of the ceramic raw material powder is preferably 1.5 to 7 g / min.

[0032] The nozzle 10 is positioned within the processing chamber 2 such that its ejection end 10a faces the holding part 5 within the processing chamber 2. As shown in Figures 1 and 2, the nozzle 10 in this embodiment is a cylindrical straight pipe member, with a transport gas supply pipe S2 connected to the end opposite to the ejection end 10a. Aerosol is supplied from the aerosol generation unit 6 through the transport gas supply pipe S2, and this aerosol is ejected from the opening of the ejection end 10a. An accelerating gas supply pipe S3, which will be described later, is connected to the pipe wall of the nozzle 10. The inner diameter Dn of the nozzle 10 is not particularly limited, but is for example about 11 to 20 mm, and in this embodiment it is 15 mm.

[0033] The conveying gas supply means 15 consists of a gas supply unit 16, a conveying gas pressure control unit 17, a conveying gas flow rate control unit 18, a conveying gas supply pipe S2, and the like.

[0034] Specifically, the gas supply unit 16 is connected to a transport gas supply pipe S2, and the gas supply unit 16 supplies gases such as air, N2, He, and Ar into the transport gas supply pipe S2 using a compressor or gas cylinder. As will be described later, the gas supply unit 16 also constitutes part of the accelerated gas supply means 20.

[0035] In this embodiment, the transport gas supply pipe S2 is for transporting the gas supplied from the gas supply unit 16 as transport gas to the nozzle 10. Specifically, in this embodiment, the gas discharged from the gas supply unit 16 is transported as transport gas to the nozzle 10 via the transport gas pressure control unit 17, the transport gas flow rate control unit 18, and the aerosol generation unit 6 in that order. The transport gas supply pipe S2 is composed of a plurality of pipes connected between the gas supply unit 16, the transport gas pressure control unit 17, the transport gas flow rate control unit 18, the aerosol generation unit 6, and the nozzle 10. Furthermore, a first pressure sensor P1 for detecting the pressure inside the transport gas supply pipe S2 is provided between the transport gas flow rate control unit 18 and the aerosol generation unit 6 in the transport gas supply pipe S2.

[0036] Furthermore, the transport gas supply pipe S2 is connected to the nozzle 10 such that its ejection end S2a is located inside the nozzle 10, and the streamline of the transport gas ejected from the ejection end S2a is straight until it reaches the ejection end 10a of the nozzle 10. In other words, the transport gas supply pipe S2 is connected to the nozzle 10 such that its ejection end S2a is located inside the nozzle 10, and its axis and the axis of the nozzle 10 are on the same straight line. The inner diameter of the transport gas supply pipe S2 is not particularly limited, but the outer diameter Dc of the part connecting the aerosol generation unit 6 and the nozzle 10 is, for example, about 6 to 18 mm. In this embodiment, it is 12.7 mm, which is smaller than the inner diameter Dn of the nozzle 10, which is 15 mm.

[0037] The conveying gas pressure control unit 17 stabilizes the conveying gas flowing through the conveying gas supply pipe S2 to an appropriate pressure, and the conveying gas flow rate control unit 18 controls the flow rate of the conveying gas flowing through the conveying gas supply pipe S2. In this embodiment, the operation of the conveying gas pressure control unit 17 and the conveying gas flow rate control unit 18 is appropriately controlled based on the pressure detected by the first pressure sensor P1.

[0038] The accelerating gas supply means 20 consists of a gas supply unit 16, an accelerating gas pressure control unit 21, an accelerating gas flow rate control unit 22, an accelerating gas supply pipe S3, and the like.

[0039] The accelerating gas supply pipe S3 is connected between the gas supply unit 16 and the transport gas pressure control unit 17 in the transport gas supply pipe S2, and is used to transport the gas supplied from the gas supply unit 16 as accelerating gas to the nozzle 10. Specifically, in this embodiment, the transport gas supply pipe S2, the accelerating gas pressure control unit 21, the accelerating gas flow control unit 22, and the nozzle 10 are connected by a plurality of pipes so that the gas sent out from the gas supply unit 16 is transported as accelerating gas to the nozzle 10 via the accelerating gas pressure control unit 21 and the accelerating gas flow control unit 22 in sequence.

[0040] Furthermore, a heater 23 (heating means) is provided on the outer wall side of the accelerating gas supply pipe S3 between the accelerating gas flow control unit 22 and the nozzle 10, and the accelerating gas flowing through the accelerating gas supply pipe S3 is heated by the heater 23. The heater 23 heats the accelerating gas supply pipe S3 so that the gas temperature (aerosol temperature) at the nozzle outlet end 10a is between 300°C and 700°C.

[0041] Furthermore, an orifice section 24 with a flow path cross-sectional area smaller than that of the accelerating gas supply pipe S3 is provided between the location where the heater 23 is installed in the accelerating gas supply pipe S3 and the nozzle 10. In addition, a second pressure sensor P2 and a third pressure sensor P3 for detecting the pressure inside the accelerating gas supply pipe S3 are provided on the upstream and downstream sides of the orifice section 24 in the accelerating gas supply pipe S3. The inner diameter of the accelerating gas supply pipe S3 and the inner diameter of the orifice section 24 are not particularly limited, but the inner diameter Da of the accelerating gas supply pipe S3 is, for example, about 4 to 10 mm, and in this embodiment it is 4.3 mm. The inner diameter Dt of the orifice section 24 is, for example, about 1.6 to 2.4 mm, and in this embodiment it is 2 mm or 2.3 mm.

[0042] Furthermore, the accelerating gas supply pipe S3 is connected to the nozzle 10 such that its ejection end S3a is located near the ejection end S2a of the transport gas supply pipe S2 within the nozzle 10, and the streamlines of the accelerating gas ejected from the ejection end S3a collide with those of the transport gas. In this embodiment, the accelerating gas supply pipe S3 is connected to the nozzle 10 in such a manner that the streamlines of the accelerating gas and the transport gas are perpendicular to each other, but this is not the only possible configuration; any positional relationship that allows the streamlines of the accelerating gas and the transport gas to collide is acceptable.

[0043] In this embodiment, the accelerating gas supply means 20 controls the flow rate of the accelerating gas flowing through the accelerating gas supply pipe S3 and the pressure inside the accelerating gas supply pipe S3 using the accelerating gas pressure control unit 21 and the accelerating gas flow rate control unit 22, so that the pressure detected by the second pressure sensor P2 installed upstream of the orifice section 24 is 600 kPaG or higher.

[0044] Next, referring to Figure 2, the following will be explained: Ia, the distance from the connection point between the nozzle 10 and the accelerating gas supply pipe S3 (center of the accelerating gas supply pipe S3) to the nozzle 10's ejection end 10a (accelerating gas supply pipe-nozzle ejection end distance); Ib, the distance from the end of the nozzle 10 opposite to the nozzle 10's ejection end 10a to the connection point between the nozzle 10 and the accelerating gas supply pipe S3 (center of the accelerating gas supply pipe S3) (lowest nozzle end-accelerating gas supply pipe distance); Ic, the distance from the end of the nozzle 10 opposite to the nozzle 10's ejection end 10a to the ejection end S2a of the transport gas supply pipe S2 (lowest nozzle end-transport gas supply pipe ejection end distance); and Id, the distance from the nozzle 10's ejection end 10a to the substrate K (nozzle ejection end-substrate distance).

[0045] In the film deposition apparatus 1 of this embodiment, the distance Ia between the accelerating gas supply pipe and the nozzle ejection end is preferably 20 mm or more. If the distance Ia between the accelerating gas supply pipe and the nozzle ejection end is shorter than 20 mm, the energy of the accelerating gas will not be easily transferred to the ceramic raw material powder, resulting in insufficient velocity. This makes it easier for compacted powder to form on the substrate K, and consequently, the film quality will deteriorate. Furthermore, the distance Ib between the lowest end of the nozzle and the accelerating gas supply pipe and the distance Ic between the lowest end of the nozzle and the ejection end of the transport gas supply pipe preferably satisfy the relationship in Equation 1, and more preferably satisfy the relationship in Equation 2. In Equations 1 and 2, Da is the inner diameter of the accelerating gas supply pipe S3. (Formula 1) Ib-Da≦Ic≦Ib+Da (Formula 2) Ib - Da / 2 ≤ Ic ≤ Ib + Da / 2

[0046] When Ic is longer than Ib+Da, the energy of the accelerating gas is less effectively transferred to the ceramic raw material powder, resulting in insufficient velocity. This makes it easier for compacted powder to form on the substrate K, leading to a decrease in film quality. On the other hand, when Ic is shorter than Ib-Da, instability occurs in the confluence of the transport gases, which also contributes to a decrease in film quality.

[0047] In this embodiment, the distance Ia between the accelerating gas supply pipe and the nozzle discharge end is 4.3 mm, the distance Ib between the lowest end of the nozzle and the accelerating gas supply pipe is 60 mm, the distance Ic between the lowest end of the nozzle and the discharge end of the transport gas supply pipe is 58 mm, and the distance Id between the nozzle discharge end and the substrate is 20 mm.

[0048] [Regarding ceramic raw material powder] The particles constituting the ceramic raw material powder used in the method for manufacturing ceramic films using the film deposition apparatus 1 are, for example, stabilized zirconia particles containing yttrium, calcium, magnesium, hafnium, etc. In this embodiment, yttrium-containing zirconia (YSZ) is used as the ceramic raw material powder.

[0049] Furthermore, while the particle size distribution of the primary particles of the ceramic raw material powder used in the method for manufacturing ceramic films using the film deposition apparatus 1 is not particularly limited, it is preferable that the primary particles of 5 μm or larger account for less than 4% by volume in order to improve film quality and adhesion efficiency.

[0050] Incidentally, the inventors of this application investigated the effect of the particle size distribution of primary particles on the film deposition results using ZrO2 with 4 mol% Y2O3 added (hereinafter referred to as "4YSZ") and ZrO2 with 8 mol% Y2O3 added (hereinafter referred to as "8YSZ"). Specifically, for 4YSZ and 8YSZ, five lots (lots No. 1 to No. 5) with different particle size distributions were prepared by milling the primary particles, and film deposition was performed using these. Table 1 summarizes the raw material composition, average particle diameter D50 of primary particles, content of particles 10 μm or larger, content of particles 5 μm or larger, content of particles 3 μm or larger, and the film deposition results for each lot.

[0051] [Table 1]

[0052] As shown in Table 1, for Lot No. 5, the raw material powder only blasted the substrate and no film was formed. For Lot No. 4, a film was formed, but the film thickness was only about 30% of that of Lot No. 3, indicating slightly lower adhesion efficiency. On the other hand, for Lots No. 1 to No. 3, films of sufficient thickness were formed, and the adhesion efficiency was very high. These differences can be attributed to differences in the proportion of primary particles larger than 5 μm. Therefore, it was found that in order to form a film when performing film deposition under the same conditions, it is important that the particle size distribution of the primary particles in the ceramic raw material powder is adjusted so that there are almost no primary particles larger than 10 μm, and primary particles larger than 5 μm account for less than 4% by volume. Furthermore, focusing on the differences between Lots No. 1 to No. 3 and Lot No. 4, Lot No. 4 contains more than 10% primary particles with a particle size in the range of 3 μm to less than 5 μm. Primary particles with a particle size between 3 μm and 5 μm also have a significant film-eroding effect (i.e., blast effect) in high-speed gas flows, so it is preferable to minimize their presence as much as possible. Therefore, it was found that in order to obtain significant adhesion efficiency, it is also important to adjust the particle size distribution of the ceramic raw material powder so that primary particles of 3 μm or larger account for less than 10% by volume.

[0053] Examples 1 to 5 and Comparative Examples 1 and 2 are described below. A film deposition process was performed on a substrate using the following: a film deposition apparatus in which the accelerating gas supply pipe of the above embodiment was replaced with one without an orifice (Examples 1 and 2), a film deposition apparatus in which the inner diameter of the orifice of the embodiment was set to 2.3 mm (Examples 3 and 4), a film deposition apparatus in which the inner diameter of the orifice of the embodiment was set to 2 mm (Example 5), and a conventional film deposition apparatus without an accelerating gas supply means (Comparative Examples 1 and 2). For the ceramic raw material powder, primary particles of Lot No. 3 shown in Table 1 were used. Table 2 summarizes the transport gas flow rate, accelerating gas flow rate, heater setting temperature, inner diameter of the orifice, absolute pressure in the processing chamber, gauge pressure downstream of the transport gas flow rate control unit, gauge pressure downstream of the accelerating gas flow rate control unit, relative density of the formed film, and adhesion efficiency for each example and comparative example. Relative density is calculated by determining the density of the film-deposited portion (weight / volume of the film deposited on the substrate) and using this as the theoretical density value (5.9 g / cm³ for this material). 3 This is the value (%) obtained by dividing by ).

[0054] [Table 2]

[0055] First, looking at Comparative Examples 1 and 2, in Comparative Example 1, the relative density of the formed film is high at 96%, but the adhesion efficiency is only about 0.3%. On the other hand, in Comparative Example 2, by heating the transport gas with a heater, the adhesion efficiency improved to about 1% compared to Comparative Example 1, but the relative density of the formed film decreased to 87%.

[0056] Next, comparing Examples 1-5 with Comparative Examples 1 and 2, Examples 1-5 all show significantly improved adhesion efficiency compared to Comparative Examples 1 and 2. For example, comparing Examples 1 and 2 with Comparative Example 2, the adhesion efficiency of Examples 1 and 2 is about 4 to 5 times higher than that of Comparative Example 2. This is because the amount of conveying gas supplied in Examples 1 and 2 is much greater than that supplied in Comparative Example 2, and the pressure downstream of the accelerating gas flow control unit is set to about 400 kPaG by supplying accelerating gas, thereby promoting the acceleration of the ceramic raw material powder. In Examples 1 and 2, the relative density of the formed film is about 70%, which is somewhat inferior in terms of density compared to Comparative Examples 1 and 2. However, unlike compacted powders that peel off easily, the formed film is a porous, thick film with a certain strength. Such films can be used as catalyst supports or electrode materials.

[0057] Furthermore, comparing Examples 1 and 2 with Examples 3 to 5, Examples 3 to 5 achieved a high adhesion efficiency (approximately 4% to 6%) similar to that of Examples 1 and 2, while also exhibiting a higher relative density of the formed film than Examples 1 and 2. This is because the presence of an orifice increases the pressure downstream of the accelerating gas flow control unit (pressure upstream of the orifice) to approximately 600 kPaG, further increasing the flow velocity of the accelerating gas in the expanded portion after passing through the orifice, thereby promoting the acceleration of the ceramic raw material powder. The relatively high-density films formed in Examples 3 to 5 can be used as electrolytes in solid oxide fuel cells.

[0058] Comparing Examples 3 to 5, in particular, Example 5 showed that the relative density of the formed film was 91%, comparable to that of Comparative Examples 1 and 2, and the adhesion efficiency was 4 to 10 times that of Comparative Examples 1 and 2. This demonstrates that high film quality can be maintained while significantly improving adhesion efficiency.

[0059] As described above, the film deposition apparatus according to the above embodiment can deposit films with a certain level of strength while significantly improving adhesion efficiency compared to conventional methods, regardless of the presence or absence of an orifice. Furthermore, by changing various conditions (such as gas flow rate, presence or absence of an orifice, and inner diameter of the orifice), films with different relative densities can be formed depending on the application of the film.

[0060] [Another embodiment] [1] In the above embodiment, an orifice section 24 is provided in the accelerating gas supply pipe S3, but the embodiment is not limited to this, and an embodiment without an orifice section may also be provided.

[0061] [2] In the above embodiment, the pressure detected by the second pressure sensor P2 provided upstream of the orifice 24 is set to 600 kPaG, but the embodiment is not limited to this. For example, the pressure upstream of the orifice 24 may be set to less than 600 kPaG. Furthermore, in the case where the orifice section 24 is not provided, it is preferable to supply the accelerating gas in such a manner that the pressure inside the accelerating gas supply pipe S3 is 400 kPaG or higher, but the invention is not limited to this.

[0062] [3] In the above embodiment, the accelerating gas supply pipe S3 is heated so that the gas temperature at the nozzle outlet end 10a is 300°C or more and less than 700°C, but the embodiment is not limited to this. The accelerating gas supply pipe S3 may be heated so that the gas temperature at the nozzle outlet end 10a is less than 300°C or 700°C or more.

[0063] The configurations disclosed in the above embodiments (including other embodiments) can be applied in combination with configurations disclosed in other embodiments, provided that no inconsistencies arise. Furthermore, the embodiments disclosed herein are illustrative, and the embodiments of the present invention are not limited thereto and can be modified as appropriate without departing from the object of the present invention. [Industrial applicability]

[0064] The present invention can be applied to a film-forming apparatus for forming a film on a substrate and a method for manufacturing a ceramic film. [Explanation of Symbols]

[0065] 1 Film deposition equipment 2 Processing Room 5 Holding part 6. Aerosol generation unit 10 nozzles 10a Spout end 15. Conveying gas supply means 20 Accelerator gas supply means 23 Heater 24 Orifice Section S2 Conveying gas supply pipe S2a spout end S3 Accelerator gas supply pipe S3a spout end

Claims

1. A processing chamber having a holding section for holding the substrate, and whose interior is reduced to a predetermined pressure or below, An aerosol generating unit that generates an aerosol in which ceramic raw material powder with an adjusted primary particle size distribution is dispersed, A nozzle is disposed in the processing chamber such that its ejection end faces the holding portion, A conveying gas supply means having a conveying gas supply pipe connected to the nozzle, which supplies the conveying gas to the ejection end of the nozzle via the aerosol generating unit, The acceleration gas supply means includes an acceleration gas supply pipe connected to the nozzle, and supplies the acceleration gas so as to merge with the transport gas flowing inside the nozzle, The acceleration gas supply pipe is provided with a heating means for heating the acceleration gas flowing through the acceleration gas supply pipe, The aforementioned conveying gas supply pipe is connected to the nozzle such that its ejection end is located inside the nozzle, and the streamline of the conveying gas ejected from the ejection end is straight to the ejection end of the nozzle. The accelerating gas supply pipe is connected to the nozzle such that its ejection end is located near the ejection end of the transport gas supply pipe within the nozzle, and the streamlines of the accelerating gas ejected from the ejection end collide with the streamlines of the transport gas. The distance from the connection point between the accelerating gas supply pipe and the nozzle to the nozzle's ejection end is 20 mm or more. A film deposition apparatus configured such that, with respect to the distance Ib from the end of the nozzle opposite to the ejection end to the connection portion with the nozzle in the accelerating gas supply pipe and the distance Ic from the end of the nozzle opposite to the ejection end to the transport gas supply pipe, the inner diameter of the accelerating gas supply pipe is Da and the following equation is satisfied. Ib-Da≦Ic≦Ib+Da

2. The film deposition apparatus according to claim 1, wherein the accelerating gas supply means supplies the accelerating gas such that the pressure in the accelerating gas supply pipe is 400 kPaG or more.

3. The film deposition apparatus according to claim 1 or 2, wherein the accelerating gas supply pipe has an orifice portion formed between the ejection end and the heating means in the accelerating gas supply pipe.

4. The film deposition apparatus according to claim 3, wherein the accelerating gas supply means supplies the accelerating gas such that the pressure in the accelerating gas supply pipe upstream of the orifice portion becomes 600 kPaG or more.

5. The film deposition apparatus according to any one of claims 1 to 4, wherein the heating means heats the accelerating gas flowing through the accelerating gas supply pipe so that the gas temperature at the ejection end of the nozzle is 300°C or more and less than 700°C.

6. A method for producing a ceramic film, comprising using the ceramic raw material powder, whose particle size distribution has been adjusted so that primary particles of 5 μm or larger account for less than 4% by volume, and producing a ceramic film using the film-forming apparatus described in any one of claims 1 to 5.

7. The method for producing a ceramic film according to claim 6, wherein the ceramic raw material powder is stabilized zirconia.

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