Method for manufacturing corrosion-resistant components and laser CVD apparatus

Abstract

To provide a method for manufacturing a corrosion resistant member, capable of preventing burning from occurring by laser beam irradiation to form an alumite film while using aluminum or aluminum alloy as a base material, and a laser CVD apparatus used for obtaining the same.SOLUTION: A method for manufacturing a corrosion resistant member comprises the film deposition step of irradiating a base material consisting of aluminum or aluminum alloy with a laser beam while spraying yttrium containing material gas thereto to form a yttria film on the surface of the base material. The laser beam has a pulse wave; the yttria film is formed at a base material temperature of 300-600°C during the film deposition; and a laser CVD apparatus is used in the method.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing a corrosion-resistant member having a substrate made of aluminum or an aluminum alloy and an yttria coating formed on the surface of the substrate, and to a laser CVD apparatus. More specifically, it relates to a method for manufacturing a corrosion-resistant member in which a yttria coating is formed by irradiating a substrate with pulsed laser light while blowing a raw material gas containing yttrium onto the substrate, and to a laser CVD apparatus for obtaining this corrosion-resistant member. [Background technology]

[0002] In etching equipment, a type of semiconductor manufacturing equipment, plasma etching is performed using highly corrosive halogen-based gases such as fluorine and chlorine. Therefore, because components inside the etching equipment are exposed to corrosive gases and plasma, highly corrosion-resistant materials are required for components such as electrostatic chucks that hold wafers and deposit shields that prevent the adhesion of etching by-products (deposits).

[0003] As plasma-resistant materials used in etching equipment, ceramic sintered bodies such as aluminum oxide (Al2O3: alumina) and aluminum nitride are known. However, these sintered bodies may be affected by corrosive gases such as fluorine and chlorine.

[0004] On the other hand, yttrium oxide (Y2O3: yttria), which has excellent plasma resistance, is more thermally stable than alumina and also has superior fluorine plasma resistance. However, rare earth elements such as yttrium are expensive. Therefore, instead of using sintered yttrium oxide bodies, technologies are being investigated to obtain corrosion-resistant components by coating the surface of parts requiring corrosion resistance with yttria (see Patent Documents 1 and 2, and Non-Patent Document 1).

[0005] Among these, Patent Document 1 describes a plasma-resistant member in which a yttrium oxide film (Y2O3 film) is formed on the surface of a substrate by chemical vapor deposition (CVD). In the example of Patent Document 1, a 100 μm thick yttrium oxide film is formed on the alumina substrate by performing CVD treatment while heating the alumina substrate at a substrate heating temperature of 700°C.

[0006] Furthermore, Patent Document 2 describes a corrosion-resistant member in which a yttrium oxide coating is formed on the surface of a substrate by a laser CVD method, which involves irradiating the substrate with a laser to form a coating. In Examples 1 to 5 of Patent Document 2, an alumina substrate is placed on a sample stage with a heater and heated to 600 to 800°C, while a mixed gas of an organometallic complex containing yttrium and oxygen gas is blown onto it. A YAG laser (a semiconductor laser in Example 5) is then irradiated through a window in the chamber to form a 50 μm thick yttrium oxide coating on the surface of the alumina substrate.

[0007] Non-patent document 1 describes how yttrium oxide can be rapidly synthesized using the laser CVD method, allowing for the deposition of a yttrium oxide film on an alumina substrate at a deposition rate of 270 μm / h. Incidentally, according to this non-patent document 1, the typical deposition rate by CVD is several μm / h (see page 845, right column, lines 8-9).

[0008] Furthermore, Patent Document 2 describes Example 6, in which a yttrium oxide film is formed by the same method as Examples 1 to 5, except that an aluminum substrate is used instead of an alumina substrate. According to this, the laser light used is understood to be a continuous wave, and in the laser CVD method using a YAG laser as the light source, the aluminum substrate melts, making it difficult to form a yttrium oxide film. However, in the case of a semiconductor laser, it is possible to form a yttrium oxide film even on an aluminum substrate, and a material with the necessary strength as a structural material and suitable as a component material for semiconductor manufacturing equipment is obtained. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2005-243758 [Patent Document 2] Japanese Patent Publication No. 2010-070854 [Non-patent literature]

[0010] [Non-Patent Document 1] Teiichi Kimura, Ryan Banal, and Takashi Goto, "Synthesis of Structurally Gradual Yttria Films by Laser CVD Method," Powder and Powder Metallurgy, Japan Society of Powder and Powder Metallurgy, Vol. 52, No. 11 (November 2005), pp. 845-850. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] In recent years, multi-patterning technology in semiconductor chip manufacturing has made it possible to form finer patterns. Consequently, the number of etching processes has increased, leading to a higher demand for etching equipment.

[0012] As mentioned above, components used inside etching equipment require highly corrosion-resistant materials. Coating the surface of these components with yttrium oxide (yttria coating), which has excellent plasma resistance and corrosion resistance, is an effective solution. In particular, laser CVD, which forms coatings by irradiating them with a laser, has a much higher deposition rate compared to CVD using conventional heating methods such as high-frequency induction heating. Therefore, it is expected to be a high-speed process for plasma-resistant and corrosion-resistant coatings that require relatively thick film thicknesses of tens to hundreds of micrometers.

[0013] Incidentally, while alumina substrates have been mainly used as the base material for forming yttria coatings by laser CVD to date, it would be advantageous to use aluminum (or aluminum alloy), which has excellent machinability and heat dissipation properties, when constructing internal components of etching equipment such as the electrostatic chucks and deposit shields mentioned above. However, the melting point of aluminum is 660°C, which is extremely low compared to the melting point of alumina, 2072°C. Therefore, the aluminum melts when irradiated with laser light by laser CVD. Patent document 2 states that yttria coatings were formed without problems using a semiconductor laser, but when the inventors actually tried it, they found that burning occurred, where the aluminum base material partially melted, causing the yttria coating to swell, or voids to form in the base material, which became a problem for the mechanical strength as a corrosion-resistant component.

[0014] Therefore, the present inventors diligently investigated a method for forming a corrosion-resistant member with an yttria coating on the surface of an aluminum or aluminum alloy substrate using laser CVD. As a result, they discovered that by using a pulsed laser with pulsed waves to deposit the film while controlling the substrate to a predetermined temperature, it is possible to prevent overheating of the aluminum or aluminum alloy substrate, suppress burning, and form an yttria coating, thus completing the present invention.

[0015] Therefore, the object of the present invention is to provide a method for manufacturing a corrosion-resistant component that can form an anodized coating while preventing burning caused by laser irradiation, using aluminum or an aluminum alloy as a base material, and is suitable for forming parts used in environments exposed to corrosive gases or plasma, such as inside an etching apparatus.

[0016] Another object of the present invention is to provide a laser CVD apparatus used to obtain the above-mentioned corrosion-resistant member. [Means for solving the problem]

[0017] That is, the gist of the present invention is as follows. (1) A method for manufacturing a corrosion-resistant member having a base material made of aluminum or an aluminum alloy and a yttria film formed on the surface of the base material, comprising: A film forming step of forming the yttria film on the surface of the base material by irradiating laser light while spraying a raw material gas containing yttrium onto the base material. The laser light is a pulsed wave. In the film forming step, the yttria film is formed at a temperature of 300°C to 600°C of the base material during film formation. In that regard, The system further includes a reflectance reduction step for reducing the reflectance of the irradiation surface of the substrate that is irradiated with the laser light, The reflectance reduction step and the film formation step are performed in this order. A method for manufacturing a corrosion-resistant member, characterized by the above. (2) The method for manufacturing a corrosion-resistant member according to (1), wherein in the film forming step, when forming the yttria film by installing the base material on a sample stage in a chamber, the temperature of the sample stage is controlled to 0°C to 200°C. (3) The method for manufacturing a corrosion-resistant member according to (2), wherein the sample stage is cooled using a liquid coolant to control the temperature. (4) The method for manufacturing a corrosion-resistant member according to any one of (1) to (3), wherein in the film forming step, the film formation rate of the yttria film is 10 to 1000 μm / Hr. (5) The method for manufacturing a corrosion-resistant member according to any one of (1) to (4), wherein in the film forming step, the laser light has an average output of 5 to 2000 W. (6) The method for manufacturing a corrosion-resistant member according to any one of (1) to (5), wherein in the film forming step, the laser light has a pulse width of 1 to 1000 ns. (7) The method for manufacturing a corrosion-resistant member according to any one of (1) to (6), wherein in the film forming step, the laser light has a peak power of 100 W to 30 kW. (8) The film In the forming step, the laser light has a pulse energy of 0.1 to 30 mJ. A method for manufacturing a corrosion-resistant member according to any one of (1) to (7). (9) The filmIn the formation process, the laser light has an average energy density of 10 to 1000 W / mm². 2 A method for manufacturing a corrosion-resistant member as described in any of (1) to (8). ( 10 )In the reflectance reduction step, the reflectance with respect to the wavelength of the laser light is reduced to 50% or less (1)~( 9 A method for manufacturing a corrosion-resistant member as described in any of the following. ( 11 ) A vacuum chamber, a sample stage on which a substrate is placed within the vacuum chamber, a gas supply device for supplying a raw material gas to the substrate, a laser device for irradiating the substrate with pulsed laser light through an optical window provided in the vacuum chamber, and a cooling device for cooling the sample stage through a refrigerant. a measurement window for measuring the temperature of the substrate during film formation using a radiation thermometer and A laser CVD apparatus characterized by being equipped with the following features. [Effects of the Invention]

[0018] According to the present invention, it is possible to form an anodized coating using aluminum or an aluminum alloy as a base material while preventing burning caused by laser irradiation. Therefore, it becomes possible to obtain corrosion-resistant components that are suitable for forming parts used in environments exposed to corrosive gases or plasma, such as the inside of an etching apparatus, and that also have excellent machinability. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is a schematic diagram illustrating a suitable laser CVD apparatus used in the method for manufacturing corrosion-resistant members according to the present invention. [Figure 2] Figure 2 shows the results of measuring the reflected light spectrum in the wavelength range of 800 to 1100 nm for the test substrates used in the examples. [Figure 3] Figure 3 shows a cross-sectional SEM image of the corrosion-resistant test member obtained in Example 1 [(a) at 100x magnification, (b) at 1000x magnification, and (c) at 5000x magnification]. [Figure 4]Figure 4 shows the surface SEM of the test corrosion-resistant member obtained in Example 1 [(a) magnification 100x, (b) magnification 1000x, (c) magnification 10000x]. [Figure 5] Figure 5 shows the EDX measurement results of the yttria coating obtained in Example 1. [Figure 6] Figure 6 shows a cross-sectional SEM image of the test corrosion-resistant member obtained in Example 2 [(a) magnification 100x, (b) magnification 1000x, (c) magnification 5000x]. [Figure 7] Figure 7 shows the surface SEM of the test corrosion-resistant member obtained in Example 2 [(a) magnification 100x, (b) magnification 1000x, (c) magnification 10000x]. [Figure 8] Figure 8 shows a cross-sectional SEM image of the corrosion-resistant member obtained in Comparative Example 1 [(a) at 100x magnification, (b) at 1000x magnification, and (c) at 10000x magnification]. [Figure 9] Figure 9 shows the surface SEM of the test corrosion-resistant member obtained in Comparative Example 1 [(a) magnification 100x, (b) magnification 1000x, (c) magnification 10000x]. [Figure 10] Figure 10 shows a cross-sectional SEM image of the corrosion-resistant member obtained in Comparative Example 2 [(a) is at 100x magnification, (b) at 1000x magnification, and (c) at 10000x magnification]. [Figure 11] Figure 11 shows the surface SEM of the test corrosion-resistant member obtained in Comparative Example 2 [(a) magnification 100x, (b) magnification 1000x, (c) magnification 10000x]. [Figure 12] Figure 12 shows a cross-sectional SEM image of the corrosion-resistant member obtained in Comparative Example 4 [(a) is at a magnification of 1000x, (b) is at a magnification of 10000x]. [Figure 13] Figure 13 shows the surface SEM of the test corrosion-resistant member obtained in Comparative Example 4 [magnification 22x]. [Figure 14] Figure 14 shows the analysis results of the EDX measurement of the yttria coating obtained in Comparative Example 4. [Modes for carrying out the invention]

[0020] The method for manufacturing corrosion-resistant members according to the present invention and the laser CVD apparatus used therefor will be described in detail below. Note that some or all of the components of the present invention described below can be combined as appropriate.

[0021] [1. Corrosion-resistant components] <Base material> First, the base material used in the manufacture of corrosion-resistant components in this invention consists of aluminum or aluminum alloy. These are distinguished by their purity; generally, those with a purity of 99.0% or higher are pure aluminum, while those with other alloying elements added are aluminum alloys. Furthermore, aluminum alloys are classified into several alloy systems, such as the 3000 series and 5000 series, depending on the main additive elements. The type of aluminum or aluminum alloy used can be selected based on various physical properties, such as the application of the corrosion-resistant component, the required strength, workability, and the corrosion resistance of the base material itself.

[0022] Furthermore, the base material may be a processed material obtained by appropriately processing it into a desired shape, or a combined material obtained by appropriately combining such processed materials. In addition, the thickness of the base material cannot be specified in general, as it varies depending on the application of the corrosion-resistant component, but generally, a thickness of about 0.1 mm to 500 mm is used. Note that an oxide film is usually formed on the surface of aluminum or aluminum alloy. This oxide film may be a naturally formed oxide film in the atmosphere, an anodic oxide film formed by anodizing, or a rolled oxide film formed by hot rolling.

[0023] The substrate used in the manufacture of corrosion-resistant components may have an oxide film on its surface or may not have an oxide film on its surface. When the substrate has an anodic oxide film formed by anodizing on its surface, the plasma resistance and corrosion resistance of both the substrate and the corrosion-resistant component are improved. Therefore, from the viewpoint of improving the plasma resistance and corrosion resistance of both the substrate and the corrosion-resistant component, it is preferable to use a substrate with an anodic oxide film on its surface and to deposit an yttria film on the anodic oxide film. However, when the substrate has an anodic oxide film on its surface, if burning occurs when depositing the yttria film on the outer surface of the anodic oxide film, a gap may be created between the inner surface of the anodic oxide film and the substrate, causing the anodic oxide film to peel off. Therefore, from the viewpoint of avoiding peeling of the anodic oxide film after the yttria film has been deposited and improving adhesion, it is necessary to suppress burning when depositing the yttria film.

[0024] <Yttria coating> The yttria coating formed on the surface of a substrate consists of yttrium oxide (Y2O3, yttria), and is formed by laser CVD, which involves irradiating the substrate with laser light while blowing a raw material gas containing yttrium onto it. The presence of the yttria coating formed on the surface of a substrate can be confirmed, for example, by observing the surface or cross-section of a corrosion-resistant component using a scanning electron microscope (SEM). Furthermore, the yttria coating can be identified, for example, by the presence of characteristic X-ray peaks of yttrium (Y) and O using energy dispersive X-ray spectroscopy (EDX, EDS).

[0025] There are no particular limitations on the thickness of this yttria coating, but a thicker film is desirable from the viewpoint of reliably exhibiting plasma resistance and corrosion resistance. On the other hand, an upper limit can be set from the viewpoint of saturation of the effect or economic considerations. Therefore, it is preferably 0.1 μm or more, more preferably 1 μm or more, preferably 100 μm or less, and more preferably 10 μm or less.

[0026] <Corrosion-resistant material> The corrosion-resistant members obtained by the present invention are equipped with an yttria coating that has excellent plasma resistance and corrosion resistance, and have a base material made of aluminum or an aluminum alloy that has excellent machinability and heat dissipation, making them suitable for use in the manufacture of parts for semiconductor manufacturing equipment in which wafers are processed while exposed to corrosive gases or plasma. In particular, they are suitable for etching components in semiconductor manufacturing equipment such as plasma etching equipment in which plasma etching is performed. Specifically, examples include the electrostatic chucks and deposit shields mentioned above, as well as cooling plates used in contact with electrodes, upper walls and side jackets that constitute part of the chamber, etc. In addition to these, the corrosion-resistant members according to the present invention can be used as various materials, including parts and housings of equipment that require plasma resistance and corrosion resistance.

[0027] [2. Method for manufacturing corrosion-resistant components] <Process for reducing reflectivity> In the method for manufacturing a corrosion-resistant member according to the present invention, a reflectance reduction step may be included prior to the film formation step, in which the reflectance of the irradiation surface of the substrate to which the laser light is irradiated is reduced. By performing the reflectance reduction step and the film formation step in this order, melting of the substrate can be suppressed, preventing burning and allowing the yttria coating to grow more reliably. In other words, by reducing the reflectance of the substrate to the laser light used in the film formation step, the substrate can store thermal energy more reliably. Preferably, the reflectance of the irradiation surface of the substrate to which the laser light is irradiated is 50% or less, more preferably 40% or less, with respect to the wavelength of the laser light used in the film formation step.

[0028] Here, there are no particular limitations on the method for reducing the reflectivity of the irradiated surface of the substrate, but examples include applying a light-absorbing material that absorbs laser light to the irradiated surface of the substrate, roughening the irradiated surface, and blackening the irradiated surface. Among these, in the method of applying a light-absorbing material, various near-infrared light-absorbing materials can be applied depending on the laser used. As for methods of roughening the irradiated surface, for example, roughening treatment can be performed by blasting, anodizing, or boehmite treatment. Furthermore, as for methods of blackening the irradiated surface, the irradiated surface of the substrate can be blackened by applying or immersing with a black dye or dark paint, or by performing electrolytic treatment to electrolyze Ni, Co, etc., by secondary electrolysis of the anodic oxide film formed by anodizing treatment.

[0029] <Film formation process> In the method for manufacturing corrosion-resistant members according to the present invention, an yttria coating is formed on a substrate made of aluminum or an aluminum alloy by so-called laser CVD. Specifically, an yttria coating is formed on the surface of a substrate made of aluminum or an aluminum alloy by irradiating it with pulsed laser light while blowing a raw material gas containing yttrium onto the substrate.

[0030] In this invention, by using pulsed laser light, the melting of a substrate made of aluminum or an aluminum alloy can be suppressed, thereby preventing burning. The laser used can be any pulsed laser and is not particularly limited; for example, YAG lasers, YVO4 lasers, semiconductor lasers, fiber lasers, excimer lasers, argon lasers, etc., can be used.

[0031] Here, when irradiating the substrate with laser light, the laser conditions can be as follows, for example. First, the average power is usually 5 to 2000 W, preferably 10 W or more, more preferably 15 W or more, even more preferably 20 W or more, preferably 1000 W or less, more preferably 100 W or less, and even more preferably 50 W or less. The frequency is usually 1 to 100 kHz, preferably 10 kHz or more, more preferably 20 kHz or more, preferably 50 kHz or less, and even more preferably 40 kHz or less. The pulse width is usually 1 to 1000 ns, preferably 10 ns or more, more preferably 50 ns or more, even more preferably 100 ns or more, preferably 500 ns or less, more preferably 300 ns or less, and even more preferably 200 ns or less. The peak power is usually 100 W to 30 kW, preferably 1 kW or more, more preferably 5 kW or more, even more preferably 10 kW or more, preferably 25 kW or less, more preferably 20 kW or less, and even more preferably 15 kW or less. The pulse energy is typically 0.1 to 30 mJ, preferably 0.5 mJ or more, more preferably 1 mJ or more, even more preferably 2 mJ or more, preferably 10 mJ or less, more preferably 5 mJ or less, and even more preferably 3 mJ or less. Furthermore, the average energy density of the laser irradiation (laser irradiation density) is typically 10 to 1000 W / mm². 2 Preferably 20 W / mm 2 More preferably 40 W / mm 2 More preferably 80 W / mm 2 The above is the standard, preferably 500 W / mm². 2 More preferably, 200 W / mm 2 More preferably, 100 W / mm 2The following applies. Average power represents the laser's oscillation power. Pulse width is the time duration of each pulse emitted from the pulsed laser. Pulse energy represents the energy of a single pulse contained within the pulsed laser. Peak power is equivalent to the pulse energy divided by the pulse width (pulse energy ~ peak power × pulse width). Furthermore, the average energy density of the laser irradiation represents the average laser output per unit area of ​​the irradiation surface of the substrate being irradiated (laser irradiation density = average power / irradiation area).

[0032] Furthermore, in the present invention, the temperature of the substrate during film formation in the film formation process is typically 300 to 600°C, preferably 350°C or higher, more preferably 400°C or higher, preferably 550°C or lower, and more preferably 500°C or lower when forming the yttria film. If the substrate temperature during film formation is below 300°C, the yttria film may not be sufficiently formed, and conversely, if it exceeds 600°C, burning may occur due to the melting of the substrate. It should be noted that it is difficult to directly measure the temperature of the substrate itself during film formation inside the chamber of the CVD apparatus. Therefore, in the present invention, the surface temperature of the substrate during film formation is measured from outside the chamber using a radiation thermometer, and that value is used as the temperature of the substrate during film formation.

[0033] To achieve the above-mentioned substrate temperature during film formation, it is preferable to control the temperature of the sample stage in the CVD apparatus chamber so that it is between 0°C and 200°C when the substrate is placed on the sample stage to form the yttria film. Specifically, it is preferable to cool the sample stage using a liquid coolant so that its temperature is typically between 0°C and 200°C, preferably 10°C or higher, more preferably 20°C or higher, even more preferably 30°C or higher, preferably 100°C or lower, more preferably 50°C or lower, and even more preferably 40°C or lower.

[0034] Furthermore, when forming the yttria film, a raw material gas containing yttria is blown onto the substrate, and pulsed laser light is irradiated while blowing this raw material gas. At this time, as in the case of forming a yttria film by CVD using known methods, organometallic complexes containing yttria can be used. Specifically, for example, acetylacetonate metal complexes such as trisacetylacetonate yttria and dipivaloylmethane metal complexes such as tris(dipivaloylmethanate)yttria are preferably used. These react with oxygen, such as oxygen gas supplied separately, to form yttria oxide. The film deposition rate of the yttria film at this time is not particularly limited, but since it is laser CVD, it is usually 10 to 1000 μm / Hr, preferably 100 μm / Hr or more, more preferably 200 μm / Hr or more, preferably 500 μm / Hr or less, and more preferably 400 μm / Hr or less.

[0035] <Laser CVD equipment> The laser CVD apparatus used in the method for manufacturing corrosion-resistant members in the present invention is not particularly limited, but preferably the following can be used. That is, a laser CVD apparatus comprising a vacuum chamber, a sample stage on which a substrate is placed in the vacuum chamber, a gas supply device for supplying raw material gas to the substrate, a laser device for irradiating the substrate with laser light through an optical window provided in the vacuum chamber, and a cooling device for cooling the sample stage with a refrigerant.

[0036] Here, Figure 1 shows one embodiment of a suitable laser CVD apparatus. In this laser CVD apparatus, a substrate 3 made of aluminum or an aluminum alloy is placed on a sample stage 2 in a vacuum chamber 1, and these raw material gases are supplied from a gas supply device 4 which has a raw material supply pipe 5 that supplies a yttrium-containing organometallic complex (MO) and an oxygen supply pipe 6 that supplies oxygen (O2). This laser CVD apparatus is also equipped with a laser device 7 that irradiates pulsed laser light, and the laser light irradiated from this device reaches the substrate 3 through an optical window 8. At this time, the optical window 8 has a lens function, so the laser light irradiated from the laser device 7 is amplified, making it possible to make the film deposition area on the surface of the substrate 3 relatively large. Furthermore, this laser CVD apparatus is equipped with a cooling device 9 that cools the sample stage 2 by circulating a liquid or gaseous coolant (R), and the temperature of the substrate 3 during film deposition can be controlled to an appropriate temperature. Furthermore, this laser CVD apparatus is equipped with an exhaust port 10 connected to a vacuum pressure device (not shown) for reducing the pressure inside the vacuum chamber 1, and a measurement window 11 for measuring the temperature of the substrate 3 during film formation using a radiation thermometer 12.

[0037] To manufacture corrosion-resistant components by forming an yttria coating on the surface of a substrate made of aluminum or an aluminum alloy using this laser CVD apparatus, first, the substrate 3 is placed in a predetermined position on the sample stage 2. After the substrate 3 placed on the sample stage 2 is brought to a predetermined temperature using a cooling device 9, an organometallic complex (MO) that has been preheated to a predetermined temperature is sprayed onto its surface from the raw material supply pipe 5 together with Ar gas, which is the carrier gas. At this time, liquid coolant (water) cooled by an external chiller or the like can be circulated through the cooling device 9. Simultaneously, oxygen (O2) is sprayed from the oxygen supply pipe 6. As a result, a mixed gas (raw material gas) containing these is sprayed onto the surface of the substrate 3.

[0038] Next, simultaneously with the blowing of the mixed gas onto the surface of the substrate 3, a laser device such as a fiber laser is introduced through the optical window 8 of the vacuum chamber 1. 7A pulsed laser beam is shone onto the surface of the substrate 3. When the laser beam is shone onto the mixed gas sprayed onto the surface of the substrate 3, the organometallic complex containing yttrium is activated by local heating and reacts with oxygen to crystallize on the surface of the substrate 3. As these crystals grow, an yttria film of a predetermined thickness is formed on the surface of the substrate 3. At this time, the substrate 3 placed on the sample stage 2 is cooled by the cooling device 9, and the laser device 7 Combined with pulse oscillation from the laser, the temperature of the substrate 3 is controlled to a predetermined temperature (300°C to 600°C) during film formation. At this time, the temperature of the substrate 3 during film formation is measured by the radiation thermometer 12, and the measurement results are then measured by the laser device. 7 It may also be used to adjust the output of the device or the refrigerant temperature of the cooling device 9. Excess gas in the vacuum chamber 1 during film formation is exhausted to the outside through the exhaust port 10.

[0039] [3. Effects and Benefits] In the method for manufacturing corrosion-resistant members according to the present invention, a pulsed laser beam is irradiated onto the surface of a substrate made of aluminum or an aluminum alloy, thereby instantaneously supplying high energy to the raw material gas and promoting the growth of yttria crystals. At this time, by using a pulsed wave, the laser beam is irradiated intermittently, causing repeated heating and cooling of the substrate. Therefore, even with a laser output comparable to that of a continuous wave, it is possible to grow an yttria film on the surface of the substrate while simultaneously preventing the substrate from receiving heat from the laser beam and suppressing the transfer of this heat into the interior of the substrate. This prevents burning, where the substrate melts and voids are formed inside the substrate. Thus, according to the present invention, even with a substrate made of a material with a relatively low melting point, such as aluminum or an aluminum alloy, it is possible to form an yttria film while suppressing melting, thereby manufacturing a corrosion-resistant member with improved plasma resistance and corrosion resistance. Furthermore, according to the present invention, since a corrosion-resistant member can be manufactured using a substrate made of aluminum or an aluminum alloy, the machinability and heat dissipation of the substrate are improved, making it possible to manufacture a corrosion-resistant member with a desired shape or excellent heat dissipation. [Examples]

[0040] Preferred embodiments of the present invention will be specifically described below based on examples, comparative examples, and test examples, but the present invention shall not be construed as being limited thereto.

[0041] [Example 1] A test substrate measuring 1 mm thick x 30 mm wide x 30 mm long was cut from an A5052 aluminum alloy (A5052-H34) treated with the tempering symbol H34 specified in JIS H0001, and a test corrosion-resistant member according to the present invention was manufactured by laser CVD as follows. First, as a reflectance reduction process for the above-mentioned test substrate, the irradiation surface to which the laser light was irradiated was blackened with a marker to reduce its reflectance. As a result, the reflectance at a wavelength of 1060 nm for the Yb fiber laser used in the laser CVD apparatus described later was 37.6%, as shown in Figure 2. The reflectance was measured using a spectrophotometer (LAMBDA 750S, PerkinElmer) in the wavelength range of 800 to 1100 nm, including for the test substrates from Example 2 onward, and the reflected light spectrum was measured to determine the reflectance at wavelengths of 976 nm and 1060 nm. In Figure 2, (i) shows the reflectance when A5052-H34 is degreased with ethanol, (ii) shows the reflectance when a sulfuric acid anodic oxide film is formed on A5052-H34, and (iii) shows the reflectance when A5052-H34 is blackened with a marker.

[0042] Next, the blackened test substrate was placed on the sample stage of the laser CVD apparatus. The laser CVD apparatus used in this example is a vertical cold-wall type as shown in Figure 1, and the laser apparatus 7 is equipped with a Yb fiber laser (wavelength λ = 1059-1065 nm) as the laser oscillator. It is also equipped with a cooling device 9 that can cool the sample stage 2 through a refrigerant. The laser apparatus 7 used was a TRUMPF (formerly SPI Lasers) redENERGY G4 20W HS-L.

[0043] After cooling the test substrate 3 placed on the sample stage 2 with the cooling device 9, an organometallic complex (MO): Y(C 11 H 19 O2)3 [tris(dipivaloylmethanato)yttrium], which was pre-heated to a predetermined temperature and vaporized, was ejected from the raw material supply pipe 5 together with Ar gas as a carrier gas. At the same time, oxygen (O2) was ejected from the oxygen supply pipe 6. Thereby, a mixed gas (raw material gas) in which these raw materials were mixed was blown onto the surface of the substrate 3.

[0044] Next, simultaneously with the blowing of the above mixed gas onto the surface of the test substrate 3, a laser device using a Yb fiber laser as a laser oscillator 7 irradiated the test substrate 3 with pulsed laser light through the optical window 8. At this time, the cooling of the sample stage 2 by the cooling device 9 and the pulsed oscillation from the laser device 7 were combined to suppress the temperature rise of the test substrate 3 during the formation of the yttria film, and the test substrate 3 was maintained at a predetermined temperature. The temperature of the test substrate 3 at that time was measured by the radiation thermometer 11. Then, while evacuating the excess gas in the vacuum chamber 1 to the outside from the exhaust port 10 and reducing the pressure in the vacuum chamber 1 to a predetermined pressure, a film forming process for forming a yttria film on the surface of the test substrate 3 was performed. The details of the laser conditions and film forming conditions in this film forming process, and the film forming results are as shown below. The peak power and pulse energy of the laser conditions are based on the data sheet of the laser device. Also, the film forming results are based on the observation by cross-sectional SEM. In addition, for the measurement of the temperature of the test substrate during film formation, a radiation thermometer (FLHX-TNN0220L0500S3.2-000 manufactured by Japan Sensor) was used. At that time, regardless of the surface state of the test substrate, the emissivity of the aluminum alloy (A5052-H34) was adopted, the emissivity was set to 0.2, and the temperature of the test substrate at the part where film formation occurred was measured. The measurement range of the radiation thermometer at this time was φ3.2 mm.

[0045] 〔Laser Conditions〕 Laser oscillator: Yb fiber laser (wavelength λ = 1059-1065 nm) oscillation Form: pulse wave Average output: 16W Frequency: 27kHz Pulse width: 200ns Peak power: 12kW or more Pulse energy: 0.8 mJ or more Laser irradiation diameter: 0.5mm Laser irradiation density: 81.53 W / mm² 2

[0046] [Film deposition conditions] Liquid coolant temperature in the cooling system: 20°C Vaporization temperature of organometallic complexes: 190°C Deposition time: 5 min Oxygen gas flow rate: 100 sccm Ar gas flow rate: 100 sccm Vacuum chamber pressure: 200 Pa Temperature of the test substrate during film formation: 420℃

[0047] [Film formation results] Yttria coating thickness: 19 μm Deposition rate: 228 μm / Hr Yttria coating shape: Fine crystalline grain stacking Melting of test substrate: None

[0048] Figure 3 shows a cross-sectional SEM image of the test corrosion-resistant member obtained by the reflectance reduction process and coating formation process described above, and Figure 4 shows a surface SEM image of the surface on the yttria coating side. Of these, Figure 4(a) (magnification 100x) confirms that the yttria coating 13 is formed within a range corresponding to the diameter of the laser beam irradiation. Furthermore, Figures 4(b) (magnification 1000x) and (c) (magnification 10000x) show that this yttria coating 13 is formed from fine crystalline grains. Moreover, Figures 3(b) (magnification 1000x) and (c) (magnification 5000x) show that the yttria coating 13 formed on the test substrate 14 is made up of stacked fine crystalline grains. Finally, Figures 3(a) (magnification 100x) and (b) confirm that no burning due to melting occurred on the test substrate 14 on which these yttria coatings 13 were formed.

[0049] On the other hand, Figure 5 shows the EDX measurement results for the yttria film obtained above. Analysis of the crystal grains forming the yttria film shown in Figure 4(c) revealed the presence of characteristic X-ray peaks for yttrium (Y) and oxygen (O), as shown in Figure 5. This indicates that the material formed on the test substrate is yttrium oxide (yttria). Figure 5 also shows a peak for carbon (C), which is thought to be the detection of some of the carbon that makes up the organometallic complex contained in the source gas.

[0050] [Example 2] A5052-H34 with dimensions of 4 mm thickness, 30 mm width, and 30 mm length was used as the test substrate. This substrate was blackened using a marker, similar to Example 1, and its reflectivity at a wavelength of 1060 nm using a Yb fiber laser was set to 37.6%. This test substrate was placed on the sample stage of the laser CVD apparatus, similar to Example 1, and an yttria film was formed on the surface of the test substrate 3, except for the laser and film deposition conditions shown below, which were the same as in Example 1. The film deposition results, along with the laser conditions, are summarized below.

[0051] [Laser conditions] Laser oscillator: Yb fiber laser (wavelength λ = 1059-1065 nm) oscillation Form: pulse wave Average output: 16W Frequency: 33kHz Pulse width: 100ns Peak power: 12kW or more Pulse energy: 0.8 mJ or more Laser irradiation diameter: 0.5mm Laser irradiation density: 81.53 W / mm² 2

[0052] [Film deposition conditions] Liquid coolant temperature in the cooling system: 20°C Vaporization temperature of organometallic complexes: 190°C Deposition time: 5 min Oxygen gas flow rate: 100 sccm Ar gas flow rate: 100 sccm Vacuum chamber pressure: 200 Pa Temperature of the test substrate during film formation: 493°C

[0053] [Film formation results] Yttria coating thickness: 14 μm Deposition rate: 170 μm / Hr Yttria coating shape: Fine crystalline grain stacking Melting of test substrate: None

[0054] Figure 6 shows a cross-sectional SEM image of the test corrosion-resistant member obtained above, and Figure 7 shows a surface SEM image of the yttria coating side. Of these, Figure 7(a) (magnification 100x) shows that although there are some areas where the yttria coating has not grown, the yttria coating 13 is formed within a range corresponding to the diameter of the laser beam irradiation, similar to Example 1. Furthermore, Figures 6(b) (magnification 1000x) and (c) (magnification 10000x) show that the yttria coating 13 is made up of stacked fine crystalline grains. Also, Figures 6(a) (magnification 100x) and (b) show that no burning due to melting occurred on the test substrate 14 on which the yttria coating 13 was formed.

[0055] [Comparative Example 1] A5052-H34 with dimensions of 1 mm thickness, 5 mm width, and 5 mm length was used as the test substrate. Without including a reflectance reduction step, the substrate was degreased with ethanol and then placed on the sample stage of the laser CVD apparatus in the same manner as in Example 1. In this Comparative Example 1, a continuous-wave semiconductor laser was used as the laser oscillator of the laser CVD apparatus. After degreasing with ethanol, the test substrate had a reflectance of 85.7% at a wavelength of 976 nm of this semiconductor laser. The film formation process for Comparative Example 1 was then performed in the same manner as in Example 1, except for the laser and film formation conditions shown below. The film formation results, along with the laser conditions, are summarized below.

[0056] [Laser conditions] Laser oscillator: Semiconductor laser (wavelength λ = 976 nm) oscillation Form: Continuous wave Output: 38W Laser irradiation diameter: 5mm Laser irradiation density: 1.94 W / mm² 2

[0057] [Film deposition conditions] Liquid refrigerant temperature in the cooling system: 15°C Vaporization temperature of organometallic complexes: 190°C Deposition time: 5 min Oxygen gas flow rate: 100 sccm Ar gas flow rate: 100 sccm Vacuum chamber pressure: 200 Pa Temperature of the test substrate during film formation: 710℃

[0058] [Film formation results] Yttria coating thickness: 0.4 μm Deposition rate: 5 μm / Hr Yttria coating shape: Fine crystalline grain stacking Melting of test substrate: Yes

[0059] Regarding the corrosion-resistant member obtained above, Figure 8 shows a cross-sectional SEM image of the cross-section, and Figure 9 shows a surface SEM image of the surface. Of these, Figures 8(c) and 9(c) (both at 10,000x magnification) confirm the presence of the yttria coating 13, but Figures 8(a) and 9(a) (both at 100x magnification) and Figures 8(b) and 9(b) (both at 1,000x magnification) do not sufficiently confirm the presence of the yttria coating, indicating that only a small amount of yttria coating 13 was formed on the surface of the test substrate 14. On the other hand, Figure 8(a) shows that burning occurred due to the melting of the test substrate 14, and that many voids 16 were formed in the test substrate 14. In this comparative example 1, it is thought that the melting occurred because the temperature of the test substrate reached 710°C during film formation due to irradiation with continuous wave laser light.

[0060] [Comparative Example 2] A5052-H34 with dimensions of 1 mm thickness, 5 mm width, and 5 mm length was used as the test substrate. As a reflectance reduction step, the test substrate was anodized with sulfuric acid to create a 34 μm thick sulfuric acid anodic oxide film, which was then roughened. As a result, the reflectance at a wavelength of 1060 nm for the Yb fiber laser used in the laser CVD apparatus of this Comparative Example 2 was 51.6%.

[0061] Next, the surface-roughened test substrate was placed on the sample stage of the laser CVD apparatus in the same manner as in Example 1. In Comparative Example 2, a continuous-wave Yb fiber laser was used as the laser oscillator of the laser CVD apparatus. The film formation process was then carried out in the same manner as in Example 1, except that the laser conditions and film formation conditions were as shown below. The film formation results, along with the laser conditions, are summarized below.

[0062] [Laser conditions] Laser oscillator: Yb fiber laser (wavelength λ = 1059-1065 nm) oscillation Form: Continuous wave Output: 8W Laser irradiation diameter: 0.5mm Laser irradiation density: 40.76 W / mm² 2

[0063] [Film deposition conditions] Liquid refrigerant temperature in the cooling system: 15°C Vaporization temperature of organometallic complexes: 190°C Deposition time: 5 min Oxygen gas flow rate: 100 sccm Ar gas flow rate: 100 sccm Vacuum chamber pressure: 200 Pa Temperature of the test substrate during film formation: 630℃

[0064] [Film formation results] Yttria coating thickness: 9.7 μm Deposition rate: 117 μm / Hr Yttria coating shape: columnar crystals Melting of test substrate: Yes

[0065] Regarding the corrosion-resistant member obtained above, Figure 10 shows a cross-sectional SEM image of the cross-section, and Figure 11 shows a surface SEM image of the surface. Of these, Figure 11(a) (magnification 100x) shows that the yttria coating 13 is formed within a range corresponding to the diameter of the laser beam irradiation. Furthermore, Figures 10(b) (magnification 1000x) and (c) (magnification 10000x), and Figure 11(b) (magnification 1000x) and (c) (magnification 10000x) show that this yttria coating is formed from an aggregate of fine columnar crystals. On the other hand, as shown in Figure 10(a) (magnification 100x), the test substrates 14 on which these yttria coatings 13 were formed experienced burning due to melting. It was found that a void 16 was formed at a part of the interface between the anodic oxide film 15 on which the yttria coating 13 was formed and the test substrate 14, and that voids 16 were also formed inside the test substrate 14. In this comparative example 2 as well, it is thought that the melting described above occurred because the temperature of the test substrate reached 630°C during film formation due to irradiation with continuous wave laser light.

[0066] [Comparative Example 3] A5052-H34 with dimensions of 1 mm thickness, 30 mm width, and 30 mm length was used as the test substrate. Without including a reflectance reduction step, the substrate was degreased with ethanol and then placed on the sample stage of the laser CVD apparatus in the same manner as in Example 1. In this Comparative Example 3, a pulsed Yb fiber laser was used as the laser oscillator of the laser CVD apparatus. After degreasing with ethanol, the test substrate had a reflectance of 88.4% at a wavelength of 1060 nm of this Yb fiber laser. The film formation process was then carried out in the same manner as in Example 1, except for the laser and film formation conditions shown below. The film formation results, along with the laser conditions, are summarized below.

[0067] [Laser conditions] Laser oscillator: Yb fiber laser (wavelength λ = 1059-1065 nm) oscillation Form: pulse wave Average output: 16W Frequency: 27kHz Pulse width: 200ns Peak power: 12kW or more Pulse energy: 0.8 mJ or more Laser irradiation diameter: 0.5mm Laser irradiation density: 81.53 W / mm² 2

[0068] [Film deposition conditions] Liquid coolant temperature in the cooling system: 20°C Vaporization temperature of organometallic complexes: 190°C Deposition time: 5 min Oxygen gas flow rate: 100 sccm Ar gas flow rate: 100 sccm Vacuum chamber pressure: 200 Pa Temperature of the test substrate during film formation: 280℃

[0069] [Film formation results] Yttria coating thickness: None (no coating formed) Deposition rate: None (no film deposition) Yttria coating shape: None (no coating formed) Melting of test substrate: None

[0070] As a result, no yttria film was formed on the surface of the test substrate. In this Comparative Example 3, it is thought that the temperature of the test substrate could not rise sufficiently during film formation due to the use of a pulsed laser and the high reflectivity of the test substrate to the laser light.

[0071] [Comparative Example 4] A1050 aluminum alloy treated with tempering symbol H24 as shown in JIS H0001 (A1050- H24A test substrate measuring 1 mm thick x 5 mm wide x 5 mm long was cut from the material. Using this test substrate, degreasing with ethanol was performed without including a reflectance reduction step, and the test substrate was placed on the sample stage of the laser CVD apparatus in the same manner as in Example 1. In this Comparative Example 4, a continuous-wave semiconductor laser was used as the laser oscillator of the laser CVD apparatus, and the reflectance of the test substrate after degreasing with ethanol was 85.7% at a wavelength of 976 nm of this semiconductor laser. Furthermore, the laser CVD apparatus in Comparative Example 4 was not equipped with a cooling device for cooling the sample stage. The film formation process was then performed in the same manner as in Example 1, except for the laser conditions and film formation conditions shown below. The film formation results, along with the laser conditions, are summarized below.

[0072] [Laser conditions] Laser oscillator: Semiconductor laser (wavelength λ = 976 nm) oscillation Form: Continuous wave Output: 64W Laser irradiation diameter: 5mm Laser irradiation density: 3.26 W / mm² 2

[0073] [Film deposition conditions] Liquid refrigerant temperature in the cooling system: None (No cooling system) Vaporization temperature of organometallic complexes: 190°C Film forming time: 10min Oxygen gas flow rate: 100 sccm Ar gas flow rate: 100 sccm Vacuum chamber pressure: 200 Pa Temperature of the test substrate during film formation: 780℃

[0074] [Film formation results] Yttria coating thickness: 17 μm Deposition rate: 102 μm / Hr Yttria coating shape: Fine crystalline grain stacking Melting of test substrate: Yes

[0075] Figure 12 shows a cross-sectional SEM image of the corrosion-resistant material obtained above, and Figure 13 shows a surface SEM image of the surface. Of these, Figure 12(a) (magnification 1000x) and Figure 12(b) (magnification 10000x) confirm the presence of an yttria coating 13 formed by the accumulation of fine crystalline grains. However, Figure 13 (magnification 22x) shows that the test substrate 14 on which the yttria coating 13 was formed underwent burning due to melting, and the test substrate 14 was significantly deformed. Figure 14 also shows the EDX measurement results for the yttria coating obtained above. As shown in Figure 14, although there are characteristic X-ray peaks for yttrium (Y) and oxygen (O), the characteristic X-ray peak for aluminum (Al) was more strongly observed than these characteristic X-ray peaks. From this result, it is considered that yttrium oxide (yttria) is formed on the test substrate 14, but it is not formed as a dense film covering the surface of the test substrate. In this comparative example 4, no cooling device was used, and the temperature of the test substrate reached 780°C during film formation due to irradiation with continuous wave laser light, which is thought to have caused the melting described above.

[0076] As described above, according to the present invention, by using a pulsed laser with pulsed waves to deposit a film on a substrate while controlling the substrate temperature, it is possible to prevent melting of the substrate made of aluminum or an aluminum alloy and suppress burning while forming an yttria coating. Therefore, it becomes possible to manufacture corrosion-resistant members with excellent plasma resistance and corrosion resistance using a substrate made of aluminum or an aluminum alloy, and the resulting corrosion-resistant members are extremely suitable as materials for parts and housings used in environments exposed to corrosive gases and plasma, such as semiconductor manufacturing equipment. [Explanation of Symbols]

[0077] 1: Vacuum chamber, 2: Sample stage, 3: Substrate, 4: Gas supply device, 5: Raw material supply pipe, 6: Oxygen supply pipe, 7: Laser device, 8: Optical window, 9: Cooling device, 10: Exhaust port, 11: Measurement window, 12: Radiation thermometer, 13: Yttria coating, 14: Test substrate, 15: Anodized coating, 16: Void.

Claims

1. A method for manufacturing a corrosion-resistant member having a base material made of aluminum or an aluminum alloy and an yttria coating formed on the surface of the base material, The process includes a coating formation step in which a yttria coating is formed on the surface of the substrate by irradiating it with laser light while blowing a raw material gas containing yttrium onto the substrate, The laser light is a pulsed wave, In the aforementioned film formation process, when forming the yttria film at a temperature of 300°C to 600°C on the substrate during film formation, The system further includes a reflectance reduction step for reducing the reflectance of the irradiation surface of the substrate that is irradiated with the laser light, The reflectance reduction step and the film formation step are performed in this order. A method for manufacturing a corrosion-resistant member, characterized by the following:

2. The method for manufacturing a corrosion-resistant member according to claim 1, wherein, in the coating formation step, when the substrate is placed on a sample stage in a chamber and the yttria coating is formed, the temperature of the sample stage is controlled to 0°C to 200°C.

3. A method for manufacturing a corrosion-resistant member according to claim 2, wherein the temperature of the sample stage is controlled by cooling it with a liquid coolant.

4. A method for manufacturing a corrosion-resistant member according to any one of claims 1 to 3, wherein in the coating formation step, the film formation rate of the yttria coating is 10 to 1000 μm / Hr.

5. A method for manufacturing a corrosion-resistant member according to any one of claims 1 to 4, wherein in the coating formation step, the laser light has an average output of 5 to 2000 W.

6. A method for manufacturing a corrosion-resistant member according to any one of claims 1 to 5, wherein in the coating formation step, the laser light has a pulse width of 1 to 1000 ns.

7. A method for manufacturing a corrosion-resistant member according to any one of claims 1 to 6, wherein in the coating formation step, the laser light has a peak power of 100 W to 30 kW.

8. The method for manufacturing a corrosion-resistant member according to any one of claims 1 to 7, wherein in the coating formation step, the laser light has a pulse energy of 0.1 to 30 mJ.

9. In the coating formation process, the laser light has an average energy density of 10 to 1000 W / mm². ２ A method for manufacturing a corrosion-resistant member according to any one of claims 1 to 8.

10. A method for manufacturing a corrosion-resistant member according to any one of claims 1 to 9, wherein in the reflectance reduction step, the reflectance with respect to the wavelength of the laser light is reduced to 50% or less.

11. A laser CVD apparatus comprising a vacuum chamber, a sample stage on which a substrate is placed within the vacuum chamber, a gas supply device for supplying a raw material gas to the substrate, a laser device for irradiating the substrate with pulsed laser light through an optical window provided in the vacuum chamber, a cooling device for cooling the sample stage through a refrigerant, and a measurement window for measuring the temperature of the substrate during film formation using a radiation thermometer.

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