Plasma resistant coating, related production method and uses

Abstract

A method for preparing a plasma-resistant coated substrate and a related coating are provided. The method includes depositing a yttrium-containing anti-plasma coating on at least a portion of the substrate via a chemical vapor deposition process, preferably atomic layer deposition (ALD). In some configurations, for example, the anti-plasma coating is formed from a mixture film composed of a mixture of an alumina compound and a yttrium oxide compound. In some cases, a multilayer laminate structure is formed comprising the mixture film alternating with deposited layers composed of metal fluorides. Components for coatings used in plasma processing apparatuses and a method for improving the resistance of a substrate to plasma corrosion are also provided.

Description

Technical Field

[0001] This invention generally relates to methods for protecting surfaces in plasma processing methods. In particular, the invention relates to preparing anti-plasma coatings on surfaces of substrates typically exposed to plasma, such as hard components mounted in the processing chamber of a plasma-assisted processing apparatus, by methods such as vapor phase chemical deposition. Prior Technology

[0002] Chemical vapor deposition methods, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD), are widely described in this field. ALD technology, often considered a subclass of CVD processes, has proven to be an effective tool for fabricating high-quality conformal coatings on a variety of three-dimensional substrate structures.

[0003] Alternating self-saturating surface reactions (ALD) are based on alternating reactions of different reactants (precursors) provided as molecular compounds or elements in a non-reactive (inert) gas carrier, which are sequentially pulsed into the reaction space containing the substrate. The substrate is then purged with an inert gas after reactant deposition. A typical ALD cycle (deposition cycle) is performed with two half-reactions (pulsing the first precursor – purging; pulsed the second precursor – purging), thereby forming a material layer (deposited layer) typically 0.05–0.2 nm thick in a self-limiting (self-saturating) manner. This cycle is repeated multiple times as needed to obtain a film with a predetermined thickness. Typical substrate exposure times for each precursor range from 0.1 to 10 seconds. Common precursors include metal oxides, elemental metals, metal nitrides, and metal sulfides.

[0004] Vacuum plasma processing chambers are used to perform plasma processing during the manufacture of devices such as photovoltaic devices and integrated circuits. Processing gases flow into the processing chamber while a field is applied to the processing gases to generate plasma.

[0005] Plasma is an ionized gas, which inherently means that equipment used in plasma treatment methods is susceptible to erosion, chemical corrosion, and changes in surface structure and morphology related to material evaporation. Plasma erosion and corrosion significantly reduce the lifespan of components used in plasma treatment equipment. To reduce operating costs, the lifespan of components exposed to plasma within the plasma treatment chamber can be extended by designing components to be plasma-resistant.

[0006] Yttrium oxide (Y₂O₃) is known to provide effective protection against oxygen plasmas and halogen plasmas such as fluorine and chlorine plasmas generated during plasma-assisted processes such as plasma etching or plasma-enhanced chemical vapor deposition (PECVD), and is widely used in the integrated circuit (IC) industry.

[0007] Typically, yttrium oxide is deposited using physical vapor deposition (PVD) or CVD methods. Compared to these techniques, the ALD method provides fully conformal coatings with fewer inherent defects on a variety of three-dimensional articles. By depositing yttrium oxide on complex components most susceptible to plasma corrosion in equipment used for plasma-assisted processing, such as showerheads, gas distribution plates, valves, etc., the equipment and its components gain additional resistance to corrosion, especially plasma corrosion, thus extending equipment life and significantly reducing the costs associated with corrosion-related repairs and maintenance.

[0008] One of the main difficulties encountered in the deposition of yttrium oxide films via ALD is related to the challenge of achieving a uniform coating using yttrium precursors and water in large-scale reaction / deposition chambers. Pure yttrium oxide films are hygroscopic and tend to absorb water molecules, which inevitably leads to problems such as drifting GPC (growth per cycle) rates (making the process difficult to control, especially in applications requiring thick films) and high local variations in H₂O, as water as a precursor is absorbed further upstream (thus making it difficult to scale up the process to large chambers). Furthermore, the water absorption and desorption rates depend on the substrate geometry, which is inconvenient for coating complex 3D components. This problem becomes more pronounced as the film volume increases, making it particularly difficult when aiming for the superior thick films desired in this application.

[0009] On the other hand, methods using ozone (O3) as an oxidant have produced stable carbonate intermediates that require high temperatures (T>325°C) to decompose, which is an extremely high temperature requirement for most commercial implementations.

[0010] For example, several ALD-enabled materials, such as aluminum oxide (Al₂O₃), are known to produce fully conformal coatings under high-velocity deposition conditions. However, several attempts to resist plasma corrosion using pure alumina coatings have revealed poor (plasma) etch resistance (approximately 10 times worse than pure Y₂O₃).

[0011] Furthermore, the deposition of pure yttrium oxide via ALD is associated with a lack of uniformity and the formation of byproducts. Another problem encountered is that yttrium precursors tend to have very low vapor pressures and are prone to recondensation. These precursors are extremely foul-smelling even at low concentrations.

[0012] Mitigating all these problems extends the deposition cycle and thus significantly reduces the overall process time and cost-effectiveness. Furthermore, in chemical deposition equipment constructed without heated pump lines, reaction byproducts tend to condense in the discharge line, and when the reaction chamber is opened, these byproducts are released into the surrounding environment, posing a health hazard to equipment operators.

[0013] In light of this, and considering the challenges associated with addressing and selecting reactive compounds suitable for generating durable protective coatings resistant to different types of plasma in a robust and cost-effective manner, further advancements in the field of plasma-resistant coatings prepared by vapor-phase chemical deposition methods such as ALD are still expected. Summary of the Invention

[0014] The object of this invention is to solve or at least mitigate each problem caused by the limitations and disadvantages of related technologies. This object is achieved through various embodiments of methods for preparing anti-plasma coated substrates, related anti-plasma coatings, and applications.

[0015] On the one hand, as defined in Independent Request 1, a method for preparing a substrate for anti-plasma coating is provided.

[0016] In one embodiment, a method for preparing a substrate for anti-plasma coating includes: obtaining a substrate, and depositing a yttrium-containing anti-plasma coating on at least a portion of the substrate by a vapor phase chemical deposition process, preferably by atomic layer deposition (ALD), wherein the anti-plasma coating comprises a mixture film consisting of a mixture of at least two compounds, one of which is a yttrium compound, particularly yttrium oxide.

[0017] In one embodiment, the mixture film is deposited in multiple deposition sequences, each of which includes depositing a first compound in at least two deposition cycles, followed by depositing a second compound, which is a yttrium compound, in a single deposition cycle.

[0018] In one embodiment, the relationship between the number of deposition cycles depositing the first compound and the number of deposition cycles depositing the second compound in the deposition sequence is 2-10 to 1, respectively.

[0019] In one embodiment, the mixture film consists of a mixture of the first compound and the second compound, wherein the second compound is yttrium(III) (Y₂O₃) and the first compound is a metal oxide other than yttrium oxide, such as any one of aluminum(III) (Al₂O₃) and zirconium(IV) (ZrO₂), or any non-lanthanide oxide.

[0020] In one embodiment, the mixture film consists of a mixture of aluminum(III) (Al₂O₃) and yttrium(III) (Y₂O₃) to obtain a solid solution of aluminum yttrium oxide (AlₓY₂⁻⁴O₃, where x>1).

[0021] In another embodiment, the method further includes depositing an additional deposition layer of metal fluoride on a deposition layer composed of a mixture film.

[0022] In one embodiment, the steps of depositing a mixture film and an additional deposited layer consisting of a metal fluoride are repeated multiple (n) times to prepare a laminated coating of the desired thickness.

[0023] In one embodiment, the metal component in the metal fluoride constituting the additional deposited layer is selected from the group consisting of yttrium (Y), lanthanum (La), strontium (Sr), zirconium (Zr), magnesium (Mg), hafnium (Hf), tereium (Tb), and calcium (Ca). Preferred metal elements include lanthanum and yttrium, with yttrium being the most preferred.

[0024] On the one hand, as defined in Independent Request 9, an anti-plasma coating is provided.

[0025] In one embodiment, the coating comprises a mixture film consisting of a mixture of at least two compounds, one of which is a yttrium compound, preferably yttrium oxide.

[0026] In one embodiment, the coating comprises a mixture film deposited in multiple deposition sequences, each deposition sequence comprising depositing a first compound in at least two deposition cycles, particularly in 2-10 deposition cycles, followed by depositing a second compound, which is a yttrium compound, in a single deposition cycle.

[0027] In one embodiment, the coating comprises a mixture film consisting of a mixture of the first compound and the second compound, wherein the second compound is yttrium(III) (Y₂O₃) and the first compound is a metal oxide other than yttrium oxide, such as aluminum(III) (Al₂O₃) and zirconium(IV) (ZrO₂).

[0028] In one embodiment, the coating comprises a mixture film consisting of a mixture of aluminum(III) (Al₂O₃) and yttrium(III) (Y₂O₃) to obtain a solid solution of aluminum yttrium oxide (AlₓY₂⁻⁴O₃, where x>1).

[0029] In one embodiment, the coating comprises a mixture film in which the yttrium content ranges from about 4 atomic percent to about 20 atomic percent.

[0030] In one embodiment, the coating further includes at least one additional deposited layer composed of a metal fluoride.

[0031] In one embodiment, the coating is configured as a multilayer laminated coating, wherein multiple layers consisting of a yttrium-containing mixture film alternate with multiple deposited layers consisting of metal fluorides.

[0032] In one embodiment, the metal component of the metal fluoride constituting the additional deposited layer is selected from the group consisting of yttrium (Y), lanthanum (La), strontium (Sr), zirconium (Zr), magnesium (Mg), hafnium (Hf), tbium (Tb), and calcium (Ca). In one embodiment, the additional deposited layer of the anti-plasma coating is composed of a metal fluoride, such as yttrium(III) fluoride (YF3).

[0033] In one embodiment, the thickness of the coating is in the range of about 10 nm to about 1000 nm, preferably in the range of about 50 nm to about 300 nm.

[0034] On the other hand, as defined in Independent Claim 18, a coated article is provided. The coated article includes a substrate coated with an anti-plasma coating according to an embodiment.

[0035] In some cases, the substrate can be any metal, metal alloy, quartz, semiconductor, and / or ceramic.

[0036] In one embodiment, the coated article is configured for use with a plasma treatment apparatus and has an assembly that exposes one or more surfaces to the plasma. The assembly may be configured as an object selected from the group consisting of: a showerhead, a diffuser for the showerhead, a base, a sample holder, a valve, a valve block, a pin, a manifold, a tube, a cylinder, a cap, and a container.

[0037] On the other hand, as defined in Independent Claim 21, the use of coated articles and / or substrates coated with anti-plasma coatings according to embodiments in the processing chamber of a plasma-assisted processing apparatus is provided.

[0038] On the other hand, as defined in Independent Claim 22, a method is provided for improving the resistance of a substrate to plasma erosion and corrosion during plasma treatment.

[0039] The utility of this invention arises from various reasons depending on each particular embodiment. In summary, this invention provides a method for preparing coatings resistant to all types of plasma corrosion using existing, well-established techniques for depositing alumina layers in ALD.

[0040] According to some implementations, plasma etching tests using Al₂O₃-Y₂O₃ and ZrO₂-Y₂O₃ mixed film coatings have demonstrated that mixed film coatings with a yttrium content of approximately 4-20 atomic percent (atomic %) exhibit resistance to halogen and oxygen plasmas similar to pure Y₂O₃. However, the mixed oxide coatings do not encounter the hygroscopic problem discussed above, which can be explained by the fact that the formation of the polycrystalline Y₂O₃ phase is interrupted by another different oxide compound. That is, Al₂O₃ (or ZrO₂, or any non-lanthanide oxide) will prevent the formation of the yttrium oxide phase, thus solving the hygroscopic problem.

[0041] Compared to the process required to deposit pure yttrium oxide films, the proposed method allows for the preparation of uniform, homogeneous coatings in a shorter time (tests show a reduction of approximately 17-fold in total deposition time), which can be explained by the shortened purging time (typical Y₂O₃ deposits require prolonged purging with an inert fluid after water treatment). Furthermore, the coating films deposited according to the disclosed method exhibit plasma barrier properties similar to those of pure yttrium oxide.

[0042] On the other hand, the proposed method utilizes the same precursor chemicals and essentially the same conditions as those developed for depositing alumina films. However, due to the mixed properties of the resulting solid film and the presence of the yttrium oxide component, the coating deposited by the proposed method can be approximately 85% thinner than conventional alumina films, while still maintaining the same anti-plasma properties. Because of the shortened deposition time, this process allows for the coating of more samples within the same timeframe, thereby reducing process-related costs while maintaining the quality associated with the preparation.

[0043] The deposited layers obtained by the ALD method have fewer inherent defects and are fully conformable, making the proposed technique highly suitable for coating profiled articles with complex 3D shapes. For example, the method presented herein provides for the manufacture of corrosion-resistant articles from profiled substrates, such as shower heads and diffusers for shower heads, with protective coatings for example, resistance to halogens, oxygen, and argon plasma.

[0044] This method also allows for extending the operational life of components that are typically exposed to plasma (the time a component is in operation before maintenance).

[0045] In this invention, materials with a layer thickness of less than 1 micrometer (μm) are referred to as "thin films".

[0046] The terms "reaction fluid" and / or "precursor fluid" in this invention refer to a fluid flow containing at least one chemical compound (precursor compound) (hereinafter referred to as precursor) in an inert carrier.

[0047] The expression “a number of” in this document refers to any positive integer starting from one (1), such as one, two, or three; while the expression “a plurality of” in this document refers to any positive integer starting from two (2), such as two, three, or four.

[0048] Unless otherwise expressly stated, the terms “first” and “second” are not intended to indicate any order, quantity or importance, but are used only to distinguish one element from another. Simple Explanation of the Diagram

[0049] Figure 1 schematically shows a substrate 20 having a coating 10 prepared according to an embodiment.

[0050] Figures 2A and 2B schematically illustrate a substrate 20 having a coating 10A prepared according to another embodiment; wherein Figure 2A schematically illustrates the formation of a deposition stack for the coating 10A.

[0051] Figures 3A and 3B show the experimental results (film composition) of coating 10 according to the embodiment. Implementation

[0052] Figures 1, 2A and 2B show the anti-plasma coatings prepared according to the embodiments, hereinafter referred to as coatings, using coatings 10 and 10A, respectively.

[0053] The term “plasma-resistant” in this document refers to resistance to erosion and / or corrosion, which is generally considered to be the degradation of a substrate material in frequent contact with plasma, such as when exposed to plasma treatment conditions generated in the treatment chamber of a plasma treatment apparatus.

[0054] Coatings 10 and 10A are advantageously designed for substrates at least partially exposed to plasma corrosion under plasma processing conditions. Such substrates include conventional hardware components used in plasma processing equipment, such as plasma etchers, reactors for plasma-enhanced chemical vapor deposition (PECVD), or reactors for plasma-assisted physical vapor deposition (PVD).

[0055] Typical hardware components include, but are not limited to, shower heads, diffusers for shower heads, bases, sample holders, valves, valve blocks, pins, manifolds, tubes, cylinders, caps, and various containers.

[0056] To prevent material degradation caused by plasma, a newly developed coating 10, 10A is proposed to protect the substrate 20 (Figures 1, 2B). This coating comprises or consists of a mixture film 11, which is composed of a mixture of at least two compounds, one of which is a yttrium compound, particularly yttrium oxide. In several configurations, the other compound forming the mixture film is a metal oxide different from yttrium oxide.

[0057] In some cases, the coating is implemented as a multilayer laminated structure (10A), wherein deposited layers consisting of a mixture film alternate with deposited layers consisting of metal halides, preferably metal fluorides. In said laminated structure, yttrium-containing mixture films alternate with films formed of pure metal fluorides. The term "pure" here means that the compound of metal fluoride does not form part of the mixture. In some cases, the laminated structure (10A) comprises a mixture film covered by a top layer consisting of metal halides, preferably metal fluorides.

[0058] A deposition layer is formed on a substrate via a vapor phase chemical deposition process, preferably via atomic layer deposition (ALD).

[0059] The basic principles of ALD growth mechanisms are known to those skilled in the art. ALD is a chemical deposition method based on the temporal introduction of at least two reactive precursor species into at least one substrate placed in a reaction vessel to deposit material on the substrate surface via sequential self-saturating surface reactions. However, it should be understood that when using, for example, photon-enhanced ALD or plasma-enhanced ALD such as PEALD, one of these reactive precursors can be replaced by energy, resulting in a single-precursor ALD process. For example, deposition of pure elements such as metals requires only one precursor. When the precursor chemical contains both elements of the binary material to be deposited, a binary compound such as an oxide can be generated using a single precursor chemical. Films grown by ALD are dense, have fewer intrinsic defects, and exhibit uniform thickness.

[0060] In terms of overall implementation, the deposition setup can be based on the deposition setup of an ALD device with the trademarks PICOSUN® P-300B ALD system or PICOSUN® P-1000 ALD system, available from Picoson Oy, Finland. However, the features constituting the concept of the invention can be incorporated into any other chemical deposition reactor embodied as, for example, an ALD, MLD, or CVD device, or any subtype thereof, such as photon-enhanced atomic layer deposition (also known as photo-ALD or flash-enhanced ALD).

[0061] An exemplary ALD reactor includes a reaction chamber that establishes a reaction space (deposition space) in which the preparation of the nano-laminated coating described herein takes place. The reactor also includes several devices configured to mediate the flow of fluids (an inert fluid and a reaction fluid containing precursor compounds P1, P2) into the reaction chamber. These devices are configured, for example, several infeed lines and associated switching and / or regulating devices, such as valves.

[0062] The basic ALD deposition cycle consists of four sequential steps: pulse A, purge A, pulse B, and purge B. During pulses A and B, the reaction fluid entering the reaction chamber is preferably a gaseous substance comprising predetermined precursor chemicals (P1, P2) carried by an inert carrier (gas). The delivery of the precursor chemicals into the reaction space and the film growth on the substrate are regulated by the aforementioned regulating devices, such as a three-way ALD valve, a mass flow controller, or any other suitable device for this purpose.

[0063] The aforementioned deposition cycle can be repeated until the deposition sequence has prepared a film or coating of the desired thickness. The deposition cycle can also be simpler or more complex. For example, the cycle may include three or more pulses of reactant vapor separated by a purging step, or certain purging steps may be omitted. On the other hand, photo-enhanced ALDs offer a variety of options, such as using only one active precursor, with various choices for purging. All these deposition cycles form a timed deposition sequence controlled by a logic unit or microprocessor.

[0064] In the method of this invention, the anti-plasma coating film (10, 10A) can be uniformly applied to any type of substrate 20, including non-specific macroscopic and / or shaped 3D objects, in a large-scale ALD reaction chamber at a deposition temperature in the range of 150-350°C, specifically at about 300°C. An example of a large-scale ALD tool is the P-1000 ALD batch processing system from Picosun®, which has a reaction chamber with a maximum cross-section of 470mm × 470mm (square), a maximum diameter of 600mm (circular), and a maximum height of 700mm.

[0065] Therefore, the method discussed in this invention allows for the deposition of a uniform yttrium-containing anti-plasma coating on a substrate in a large ALD chamber.

[0066] Referring to Figure 1, a coating 10 consisting of a mixture film 11 is shown. The mixture film 11 is deposited in multiple deposition sequences (S1, S2, S3…Sn), such as the ALD deposition sequence, wherein each of the deposition sequences includes depositing a first compound in at least two deposition cycles, followed by depositing a second compound in a single deposition cycle. In the deposition sequence intended to prepare the mixture film, the second compound is a yttrium compound.

[0067] In some configurations, the mixture film 11 is therefore composed of a mixture of a first compound and a second compound, wherein the second compound is yttrium(III) (Y₂O₃) and the first compound is a metal oxide other than yttrium oxide, such as either aluminum(III) (Al₂O₃) or zirconium(IV) (ZrO₂).

[0068] In some other configurations, the first compound is provided as strontium oxide (SrO), niobium oxide (IV)(NbO 2), hafnium oxide (IV)(HfO 2), or tantalum oxide (V)(Ta 2O 5). For example, the use of any other suitable compound, such as non-lanthanide oxides, is not excluded.

[0069] In one configuration, the mixture film 11 forming the coating 10 is composed of a mixture of aluminum(III) (Al₂O₃) and yttrium(III) (Y₂O₃) to obtain a solid solution of aluminum yttrium oxide (AlₓY₂⁻ₓO₃, where x>1).

[0070] In this invention, the terms "solid solution" and "mixture film" are used interchangeably. It is used to indicate a mixed layer of (nano)materials present in a homogeneous solid phase having a second component completely and uniformly dispersed in a solid medium. According to some literature sources, one of the components in a solid solution acts as the "host" (corresponding to the solvent in a liquid solution), and the other(multiple) components act as "guests" (corresponding to the dissolved substances in the liquid solution). Experimental data (e.g., X-ray spectroscopy) for such solid solutions are generally expected to match data for the pure "host" component.

[0071] In this example, the “host” component is the first compound, which is a non-yttrium metal oxide (e.g., Al₂O₃), while yttrium oxide (Y₂O₃) serves as the “guest” (second compound). To generate the exemplary solid solution / mixture film 11, the following deposition sequence is employed during the deposition process. First, Al₂O₃ is deposited through several deposition cycles using trimethylaluminum (TMA, Al(CH₃)₃) as the first precursor and water as the second precursor.

[0072] For example, in a deposition cycle, the same deposition sequence continues to deposit yttrium oxide by yttrium precursor (first precursor) and water (second precursor). This produces a sub-monolayer of "Y₂O₃" (in parentheses because there are no discernible layers or even particles of Y₂O₃ in the "host" material).

[0073] The deposition process continues with the next deposition sequence, where the deposition of Al₂O₃ is followed by the deposition of Y₂O₃. In this way, "Y₂O₃" is completely and uniformly dispersed in the solid medium (Al₂O₃ or other suitable "host" compound) to obtain a solid solution of yttrium aluminum oxide (Al₂xY₂-xO₃). In this invention, the solid solution of yttrium aluminum oxide is also referred to as Al₂O₃-Y₂O₃.

[0074] The use of other suitable precursors is not excluded. For example, regardless of whether zirconium oxide (ZrO₂) is used as the first compound, it can be deposited using tetra(ethylmethyl-amino)zirconium (TEMAZr) and H₂O precursors.

[0075] Thin ALD coatings are typically amorphous (non-crystalline), therefore, the resulting mixture film 11 should be described more as a “solution”, in contrast to doped semiconductor or ordered crystalline materials.

[0076] To avoid confusion, we note that the boundaries between the “layers” prepared by each deposition sequence (S1, S2, S3…Sn) indicated by dashed lines in Figures 1 and 2 are for illustrative purposes only. In practice, as described above, the mixture film layer 11 is deposited as a uniform, homogeneous material layer.

[0077] The relationship between the number of deposition cycles for depositing the first compound (e.g., Al₂O₃) and the number of deposition cycles for depositing the second compound (e.g., Y₂O₃) in the deposition sequence is 2–10 to 1, respectively. In some cases, the first compound may be deposited in 2–7 cycles (per deposition sequence: S1, S2, S3…Sn). However, the second (“guest”) compound is deposited in one cycle per deposition sequence.

[0078] Therefore, the yttrium content in the mixture membrane 11 ranges from about 4 atomic percent to about 20 atomic percent. In some cases, the total yttrium content in the mixture membrane 11 is typically in the range of about 5-20 atomic percent.

[0079] An exemplary method for preparing the coating 10 provided as a mixture film 11 is presented in Example 1. The mixture film 11 thus formed is a solid solution of yttrium aluminum oxide (Al xY 2-xO 3).

[0080] Example 1. Formation of a coating 10 provided as a mixed film Al x Y 2-x O 3 (solid solution):

[0081] 1. Formation of the first compound (Al₂O₃): 1a. Pulsing a first precursor (e.g., TMA) to form a first compound; 1b. Pulse the second precursor (H₂O or O₃) to form the first compound. Repeat 1a and 1b 1-9 times (to achieve a total of 2-10 deposition cycles).

[0082] 2. Formation of a second compound (Y₂O₃): 2a. Pulse the first precursor to form the second compound (any suitable Y precursor, such as tris(methylcyclopentadienyl)yttrium(III) / Y(MeCp) 3); 2b. Pulse a second precursor (e.g., H₂O) to form a second compound.

[0083] End of the first deposition sequence.

[0084] The deposition sequence (steps 1(1a-1b) and 2(2a-2b)) is repeated a predetermined number of times to generate a mixture film 11 (also known as coating 10) of the desired thickness. For example, to deposit a coating with a depth / thickness in the range of about 180 nm to about 9900 nm, steps 1 and 2 can be repeated 1000-10000 times.

[0085] In certain specific instances, the deposition sequence for preparing the mixture film 11 comprises three (3) TMA-H₂O deposition cycles (to prepare the first compound, Al₂O₃ herein) and one Y(MeCp)₃-H₂O cycle (to prepare the second compound, Y₂O₃ herein). In this example, the total yttrium content in the mixture film 11 is in the range of approximately 10 atomic percent.

[0086] In summary, we emphasize that yttrium compounds are deposited in a cycle for each deposition sequence (also known as, for example, a cycle of Y precursor and H₂O).

[0087] Suitable Y precursors include, but are not limited to: Y(thd)3(tris(2,2,6,6-tetramethyl-3,5-heptanedione)yttrium(III)), Y(Cp)3(tris(cyclopentadienyl)yttrium(III)), Y(EtCp)3(tris(ethylcyclopentadienyl)yttrium(III)), Y(iPrCp)3(tris(isopropylcyclopentadienyl)yttrium(III)), Y(n-BuCp)3(tris(n-butylcyclopentadienyl)yttrium(III)), Y(s-BuCp)3(tris(sec-butylcyclopentadienyl)yttrium(III)), Y(EDMDD)3(tris(6-ethyl-2,2-dimethyl-3,5-decanedione)yttrium), ARYA™, YERBA™ (the latter two are available from Air Liquide).

[0088] The thickness of the coating 10 deposited as described above is typically in the range of about 10 nm to about 1000 nm, preferably in the range of about 50 nm to about 300 nm. In some specific examples, the coating 10 may be formed to have a thickness of about 20-100 nm.

[0089] Nevertheless, the ALD technology thus utilized allows for the deposition of coatings with a thickness exceeding 1000 nm10, for example, up to 2 or 3 micrometers (μm), or even up to 10 micrometers.

[0090] The ALD systems P-300B and P-1000 (both Picosun®) were used to deposit an anti-plasma coating (10) consisting of a mixture film 11. Subsequent tests have shown that coating 10 (P-300B) best maintains anti-plasma corrosion properties compared to conventional coatings consisting of (pure) Y₂O₃. Therefore, the mixture film 11 containing about 20 atomic percent yttrium (and the coating 10 formed from said film) exhibits similar anti-plasma (such as fluorine or oxygen plasma) corrosion resistance (about 80% in absolute value, and about 85% when compared to alumina films) to conventional Y₂O₃ films, and significantly higher corrosion resistance compared to alumina (Al₂O₃) films of similar thickness.

[0091] Maintaining the total yttrium content in the mixture film 11 within the range of approximately 4-20 atomic percentages allows the coating 10 to be prepared according to existing robust ALD processes (i.e., in the same manner as, for example, depositing an alumina film from TMA-H2O).

[0092] Figures 3A and 3B show the experimental results relating to the composition of coating 10 (deposited on P-300B at 300°C). The observed film composition matches expectations and is consistent throughout the film (see Table 1 and Figure 3A below, showing the results of Time-of-Flight Elastic Backflush Detection Analysis (ToF ERDA)). Impurity levels are very low.

[0093] Table 1. Composition of coating 10 formed from mixture film 11. Al Y O C H Concentration (atomic percentage) 33.9 6.12 59.4 0.6 <DL Uncertainty 0.4 0.07 0.5 0.07 0.02

[0094] According to X-ray reflectance (XRR) measurements, the density of coating 10 is 3.45 ± 0.05 g / cm³ and the roughness is 0.74 ± 0.01 nm.

[0095] The film composition can be accurately estimated based on the refractive index (n) measured at a wavelength of 633 nm on the solid solution coating 10 (Figure 3B). The composition is independent of the deposition tool. The results are summarized in Table 2 below (see also Figure 3B).

[0096] Table 2. Results obtained from measuring the refractive index (n) of coating 10 formed from mixture film 11 (solid solution Al xY 2-xO 3) at 633 nm. Al Y O C H Molecular formula ToF-ERDA 33.9 6.12 59.4 0.6 <DL Al 1.7Y 0.3O 3 experiment* 33.3 6.67 60.0 0 0 Al 1.67Y 0.33O 3 calculate** 32.0 8.0 60.0 0 0 Al 1.6Y 0.4O 3 * refers to the expected value based on the experimental model. ** refers to the actual measurement data obtained in the ToF-ERDA measurement.

[0097] Referring to Table 2 and Figure 3B, the experimental model is a linear fit, where the n-values ​​are plotted based on the Y₂O₃ cycle ratio. The slope and crossover allow for estimation of the yttrium content in the solid solution (mixture film 11) forming coating 10, which was later confirmed by ToF-ERDA measurements.

[0098] For coating 10 deposited using the large-scale ALD system P-1000, coating uniformity was tested on flat surfaces and on molded 3D objects. It was found that uniform coatings with good process dimensions and fewer inherent defects can be deposited on large substrates within the reaction chamber sized for the ALD tool P-1000. In the test experiments, the deposition temperature was 300°C; the duration of the non-yttrium pulse was 0.5 seconds, and the purging duration was 30–40 seconds.

[0099] In summary, it has been demonstrated that the mixed film 11 (solid solution Al xY 2-xO 3) can be formed using a mature process with TMA and water precursors (requiring only one yttrium compound deposition cycle per deposition sequence). One of the key findings is that the corrosion resistance of the mixed film is not linearly related to its Y 2O 3 content. Therefore, if the etch rate of pure Y 2O 3 is 1, the etch rate of the coating 10 with the mixed film 11 is 1.5 to 2 times that rate, while the etch rate of pure Al 2O 3 is 10 times that of (pure) Y 2O 3. However, compared to coatings made from pure yttrium oxide, the mixed film coating 10 is more uniform and its deposition is faster.

[0100] Meanwhile, the plasma resistance of coating 10 is approximately five times that of conventional alumina films. Coating 10, possessing the aforementioned barrier properties, is deposited in several deposition sequences, each consisting of three deposition cycles of TMA-H₂O (to prepare Al₂O₃) and one cycle of Y-precursor-H₂O (to prepare Y₂O₃). Therefore, a significantly thinner coating (10) can be used to provide the same corrosion resistance compared to conventional alumina coatings.

[0101] In other words, the hybrid film coating (10) has similar plasma resistance (especially fluorine plasma) to coatings composed of pure yttrium oxide (and its resistance is about 5 times higher than that of pure alumina coatings). At the same time, the hybrid film coating (10) can be deposited using mature technologies, such as those used for depositing Al₂O₃.

[0102] Referring to Figures 2A and 2B, the formation of an anti-plasma coating according to another embodiment is illustrated. To deposit coating 10A (Figures 2A and 2B), the method generally discussed above and presented in Example 1 is further extended such that an additional deposition layer 12 is deposited on the deposition layer composed of a yttrium-containing mixture film 11. The additional deposition layer 12 is preferably composed of a metal fluoride.

[0103] The metallic components in metal fluorides are represented by at least the following chemical elements: yttrium (Y), lanthanum (La), strontium (Sr), zirconium (Zr), magnesium (Mg), hafnium (Hf), tbium (Tb), and calcium (Ca).

[0104] Metal fluorides include, but are not limited to, yttrium(III) fluoride (YF3), lanthanum(III) fluoride (LaF3), strontium(I1) fluoride (SrF2), zirconium(IV) fluoride (ZrF4), magnesium(I1) fluoride (MgF2), hafnium(IV) fluoride (HfF4), terbium(III) fluoride (TbF3), and calcium(II) fluoride (CaF2). Any other suitable compound may be used. Preferred compounds include LaF3 and YF3, with YF3 being the most preferred. Therefore, in certain specific configurations, the additional deposited layer 12 consists of yttrium(III) fluoride (YF3).

[0105] The metal fluoride that forms the additional deposited layer is also referred to as “pure,” meaning that the compound does not form part of the mixture.

[0106] In some other cases, for example, the additional deposited layer may consist of a metal halide, which is different from a metal fluoride, such as a metal chloride (e.g., yttrium chloride).

[0107] Figure 2A shows the formation of an additional deposition layer 12 on top of the mixture film 11. The additional deposition layer 12 (see Example 1) can be deposited on the mixture film 11 described above as a single top layer.

[0108] The deposition process can also continue by repeating the steps of depositing the mixture film 11 and an additional deposition layer 12 composed of metal fluoride several (n) times (shown in Figure 2A) to prepare a laminated coating of the desired thickness. Figure 2B shows a laminated coating 10A including alternating layers (11 and 12).

[0109] Coating 10A may therefore include multiple deposited layers arranged on top of each other to form a “stack” (see layers 11, 12 repeated n times). Layers (11, 12) form “sub-stacks” (as shown in Figure 2A). For clarity, we note that the total number of said sub-stacks (n) and the total number of deposited layers can vary depending on the layer composition, the substrate to be coated, and the latter’s application area. For example, the total number of “sub-stacks” can vary in the range of 2-100. In most cases, n varies in the range of 5-20.

[0110] Example 2 presents an exemplary method for preparing a laminated coating 10A comprising several “sub-stacks” (11, 12) repeated n times. In this example, the deposited layer (11) is a mixture film (solid solution) of aluminum yttrium oxide (Al xY 2-xO 3) and the deposited layer (12) is a metal fluoride.

[0111] Example 2. Formation of laminated coating 10A:

[0112] I. Formation of sedimentary layers (11).

[0113] 1. Formation of the first compound (Al₂O₃): 1a. Pulsing a first precursor (e.g., TMA) to form a first compound; 1b. Pulse the second precursor (H₂O or O₃) to form the first compound.

[0114] Repeat 1a and 1b 1-9 times (to achieve a total of 2-10 deposition cycles).

[0115] 2. Formation of a second compound (Y₂O₃): 2a. Pulse the first precursor to form the second compound (any suitable Y precursor, such as tris(methylcyclopentadienyl)yttrium(III) / Y(MeCp) 3); 2b. Pulse a second precursor (e.g., H₂O) to form a second compound.

[0116] End of the first deposition sequence.

[0117] Repeat the deposition sequence (steps 1(1a-1b) and 2(2a-2b)) a predetermined number of times to generate a mixture film 11 of the desired thickness. For example, to deposit a coating with a depth / thickness of 20-100 nm, steps 1 and 2 can be repeated 200-500 times.

[0118] II. Formation of sedimentary layer 12.

[0119] 3. Formation of an additional deposition layer composed of metal fluoride (here, yttrium fluoride, YF3): 3a. Pulse the first precursor to form the deposition layer (12) (any suitable Y precursor, such as Y(hfac)3EME); 3b. Pulse a second precursor to form a deposition layer (12) (e.g., O3).

[0120] Repeat steps 3a and 3b 100-600 times.

[0121] Steps I and II can be repeated a predetermined number of times to achieve the target thickness of the laminated coating 10A, which includes alternating layers (11 and 12).

[0122] By repeating step I a predetermined number of times to prepare a mixture film 11 of the desired thickness, and then forming the topmost deposition layer (12) according to step II, the deposition process of Example 2 can be performed. This results in the preparation of a laminated structure (10A) comprising the mixture film 11 and an additional deposition layer 12 composed of metal fluoride.

[0123] When the metal fluoride used is yttrium fluoride, the deposition of yttrium fluoride can be achieved with different precursors, for example, with a combination of Y(thd)3-TiF4(P1-P2), or with any other suitable compound including the Y precursor as indicated in the deposition mixture film 11 (and coating 10).

[0124] For the laminated coating 10A, it may be preferable to use different yttrium precursors (Y(MeCp)3 and Y(hfac)3EME, respectively) in process stages I and II (steps 2a and 3a, respectively). However, the use of the same Y precursor throughout the process is not excluded.

[0125] In coating 10A, a stack of multiple deposited layers has a thickness ranging from about 10 nm to about 1000 nm; therefore, the laminated structure presented here is also referred to as a "nanoplastomer". Regarding coating 10A, the terms "structure" (nanoplastomer structure) and "stack" (nanoplastomer stack) are used interchangeably in this invention. Nanoplastomer stacks with thicknesses ranging from 10 nm to 1000 nm, preferably from 50 nm to 500 nm, and even more preferably from 100 nm to 300 nm can be prepared. The most typical and, in some cases, preferred range for the deposited nanoplastomer structure 10A includes 50-300 nm, i.e., 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, and 300 nm.

[0126] In the laminated structure 10A, the deposited layer (11) consisting of a mixture film (forming coating 10) typically has a thickness of 20-100 nm.

[0127] Nevertheless, by repeating steps I and II (Example 2) a predetermined (n) number of times, the ALD technology used here allows for the fabrication of laminated structures with a thickness exceeding 1000 nm (up to about 2-3 micrometers or even up to 10 micrometers) (10A).

[0128] In fact, by repeating steps I and II (Example 2) 5-20 times, laminated coatings with thicknesses ranging from 250 nm to up to 10,000 nm can be prepared.

[0129] Referring to Figure 2B, separate sedimentary layers (11)n, (12)n are formed in several sedimentary cycles (with a basic sequence of P1-purge-P2-purge according to any one or more examples).

[0130] The process for preparing any one of coatings 10 and 10A may further include pretreatment and post-treatment steps. Therefore, the process may further include: obtaining a substrate 20 and placing the substrate in the reaction / processing chamber of a suitable chemical deposition apparatus, such as the processing chamber of an ALD apparatus. The chamber and substrate are further heated to 150-325°C to stabilize the chamber. Optionally, the substrate is pretreated to prepare its surface for further deposition: for example, the substrate may be treated in situ with a suitable gas and / or an additional ALD layer may be deposited thereon to improve the adhesion of coatings 10 and 10A. After depositing coatings 10 and 10A, it is preferable to allow the substrate to be cooled in a vacuum, in an inert atmosphere, or in ambient air.

[0131] However, it has been demonstrated that coating 10, provided as a solid solution film (10), deposited on a substrate that is not silicon (e.g., a metal), does not require pretreatment of the substrate to allow the coating 10 to adhere. Several experimental tests have been conducted involving coating 10 provided as a solid mixture film of Al₂O₃-Y₂O₃ on silicon (Si) and metal (stainless steel) substrates. The total thickness of coating 10 is 300 nm. The resistance of the coating to separation from the substrate was evaluated according to standard ISO 2409:2013 (varnishes and varnishes—cross-cut test). The samples tested included: 1) coated with 10 1) Si substrate with 10 coating, no pretreatment; 2) SS substrate with 10 coating, no pretreatment; 3) SS substrate with O3 pretreatment (30 minutes) and 10 coating; 4) SS substrate with 10 coating and subjected to a washing process*; 5) SS substrate with O3 pretreatment (30 minutes), 10 coating and subjected to a washing process*.

[0132] *The washing process includes the following steps: 1) Sonication with isopropanol (IPA) for 5 minutes at room temperature (RT); 2) Sonication with deionized water for 5 minutes at room temperature; 3) Repeat steps 1 and 2; 4) Drying with nitrogen (N2).

[0133] Of all the test samples (1-5), coating 10 showed adequate adhesion to substrates (including stainless steel substrates without any pretreatment) (grade 0).

[0134] Both coatings 10 and 10A provide excellent corrosion resistance. For example, coating 10, provided as a solid mixture (Al₂O₃-Y₂O₃) film, exhibits most of the corrosion resistance properties of the Y₂O₃ film. The laminate structure 10A can be used to enhance corrosion resistance and thus provide additional protection to the substrate.

[0135] The trademark for coatings 10 and 10A is PicoArmour™ by Picosun Oy of Finland.

[0136] The present invention also relates to a coated article comprising a substrate 20 coated with an anti-plasma coating 10, 10A according to an embodiment. The coated article is advantageously configured to have a hard component with the coating 10, 10A deposited on at least a portion of its surface.

[0137] This component can be configured as a three-dimensional object suitable for coating by chemical deposition methods. The inventive concept is also applicable to preparing coatings on substantially flat planar substrates and on shaped substrates containing high aspect ratio features such as recesses and / or perforations (often referred to as "profiles"). The shaped substrate can be configured as a perforated substrate, a substrate with patterned surfaces, or a combination of perforations with patterned surfaces. Profiles can be configured as discrete (e.g., in the form of discrete individual openings / holes) or continuous, such as grooves, channels (including through channels), trenches, etc.

[0138] Components are typically used with plasma processing equipment and have one or more surfaces exposed to plasma. Therefore, in some cases, components are selected from the group consisting of: showerheads, diffusers for showerheads, bases, sample holders, valves, valve blocks, pins, manifolds, tubes, cylinders, caps, and containers.

[0139] On one hand, there is a provision for the use of a coated article and / or substrate 20, according to an embodiment, coated with an anti-plasma coating (10, 10A), in a processing chamber of a plasma-assisted processing apparatus. The apparatus can be configured as a plasma etching apparatus, an apparatus for plasma-enhanced chemical vapor deposition, or an apparatus for plasma-assisted physical vapor deposition. The apparatus can be configured to generate halogen plasmas (e.g., fluorine plasma, chlorine plasma), oxygen plasmas, argon plasmas, etc.

[0140] On the other hand, a method is provided for improving the resistance of a substrate to plasma erosion and corrosion during plasma treatment. The method includes obtaining a substrate and accommodating the substrate in a reaction chamber, followed by depositing multiple layers of deposits, preferably by atomic layer deposition (ALD), through a vapor phase chemical deposition process to form a yttrium-containing anti-plasma coating on at least a portion of the substrate surface, such that deposited layers having a first component alternate with deposited layers having a second component. In this method, the deposited layers having the first component are a mixture film (11) composed of a mixture of at least two compounds, one of which is a yttrium compound, preferably yttrium oxide, while the deposited layers (12) having the second component consist of a metal fluoride.

[0141] In some configurations, the deposited layer having the first component is a mixture film 11 consisting of a mixture of a first compound and a second compound, wherein the second compound is yttrium(III) (Y₂O₃) and the first compound is a metal oxide other than yttrium oxide, such as any one or any non-lanthanide oxide of aluminum(III) (Al₂O₃) and zirconium(IV) (ZrO₂), and the deposited layer (12) having the second component is composed of metal fluorides, especially yttrium(III) fluoride (YF₃).

[0142] Those skilled in the art will understand that, with advancements in technology, the basic ideas of this invention can be implemented and combined in various ways. Therefore, this invention and its embodiments are not limited to the examples described above; rather, they can generally be varied within the scope of the patent application.

[0143] 10, 10A: Coating 11: Mixture membrane 12: Additional Deposition Layer 20: Base

Claims

1. A method for preparing a plasma-resistant coated substrate, the method comprising the steps of: obtaining a substrate; and depositing a plasma-resistant coating on at least a portion of the substrate by an atomic layer deposition (ALD) process, wherein, The anti-plasma coating comprises a mixture film consisting of a mixture of at least two compounds, one of which is yttrium oxide. The method further comprises: depositing an additional deposition layer consisting of a metal fluoride on a deposition layer consisting of the mixture film, wherein the steps of depositing the mixture film and the additional deposition layer consisting of the metal fluoride are repeated several (n) times to prepare a laminated coating of desired thickness.

2. The method as described in claim 1, wherein, The mixture film is deposited in multiple deposition sequences, each of which includes depositing a first compound in at least two deposition cycles, followed by depositing a second compound, which is the yttrium oxide, in a single deposition cycle.

3. The method as described in claim 2, wherein, In the deposition sequence, the ratio of the number of deposition cycles depositing the first compound to the number of deposition cycles depositing the second compound is 2-10 to 1.

4. The method as described in claim 2, wherein, The mixture film is composed of a mixture of the first compound and the second compound, wherein the second compound is yttrium(III) (Y2O3) and the first compound is a metal oxide other than yttrium(III) (Al2O3) and either aluminum(III) (Al2O3) or zirconium(IV) (ZrO2).

5. The method as described in claim 1 or 2, wherein, The mixture film is composed of a mixture of aluminum(III) (Al2O3) and yttrium(III) (Y2O3) to obtain a solid solution of aluminum yttrium oxide (AlxY2-xO3).

6. The method as described in claim 1, wherein, The metal components in the metal fluoride that makes up the additional deposited layer are selected from the group consisting of: yttrium (Y), lanthanum (La), strontium (Sr), zirconium (Zr), magnesium (Mg), hafnium (Hf), terbium (Tb), and calcium (Ca).

7. An anti-plasma atomic layer deposition (ALD) coating comprising a mixture film consisting of a mixture of at least two compounds, one of which is yttrium oxide; and at least one additional deposition layer consisting of a metal fluoride, the additional deposition layer being deposited on the mixture film.

8. The anti-plasma atomic layer deposition (ALD) coating as described in claim 7, wherein, The mixture film is deposited in multiple deposition sequences, each of which includes depositing a first compound in at least two deposition cycles, followed by depositing a second compound, which is the yttrium oxide, in a single deposition cycle.

9. The anti-plasma atomic layer deposition (ALD) coating as described in claim 7, wherein, The mixture film is deposited in multiple deposition sequences, each of which includes depositing a first compound in 2-10 deposition cycles, followed by depositing a second compound, which is the yttrium oxide, in a single deposition cycle.

10. An anti-plasma atomic layer deposition (ALD) coating as described in claim 8 or 9, wherein, The mixture film is composed of a mixture of the first compound and the second compound, wherein the second compound is yttrium(III) (Y2O3) and the first compound is a metal oxide other than yttrium(III) (Al2O3) and either aluminum(III) (Al2O3) or zirconium(IV) (ZrO2).

11. The anti-plasma atomic layer deposition (ALD) coating as described in any one of claims 7 to 9, wherein, The mixture film is composed of a mixture of aluminum(III) (Al2O3) and yttrium(III) (Y2O3) to obtain a solid solution of aluminum yttrium oxide (AlxY2-xO3).

12. The anti-plasma atomic layer deposition (ALD) coating as described in any one of claims 7 to 9, wherein, The yttrium content in the mixture membrane is in the range of about 4 atomic percent to about 20 atomic percent.

13. The anti-plasma atomic layer deposition (ALD) coating as described in any one of claims 7 to 9, wherein, Multiple deposition layers composed of the mixture film alternate with multiple deposition layers composed of the metal fluoride.

14. The anti-plasma atomic layer deposition (ALD) coating as described in claim 7, wherein, The metal components in the metal fluoride that makes up the additional deposited layer are selected from: yttrium (Y), lanthanum (La), strontium (Sr), zirconium (Zr), magnesium (Mg), hafnium (Hf), terbium (Tb), and calcium (Ca).

15. An anti-plasma atomic layer deposition (ALD) coating as described in any one of claims 7 to 9, having a thickness in the range of about 10 nm to about 1000 nm.

16. An anti-plasma atomic layer deposition (ALD) coating as described in any one of claims 7 to 9, having a thickness in the range of about 50 nm to about 300 nm.

17. A coated article comprising a substrate coated with an anti-plasma atomic layer deposition (ALD) coating as described in any one of claims 7 to 16.

18. The coated article as described in claim 17, which is configured for use with a plasma processing apparatus and has components that expose one or more surfaces to plasma.

19. The coated article as described in claim 17 or 18 is constructed to consist of components selected from: a shower head, a diffuser for the shower head, a base, a sample holder, a valve, a valve block, a pin, a manifold, a tube, a cylinder, a cap, and a container.

20. Use of an article coated as described in any one of claims 17 to 19 and / or a substrate coated with an anti-plasma atomic layer deposition (ALD) coating as described in any one of claims 7 to 16 in a processing chamber of a plasma-assisted processing apparatus, said plasma-assisted processing apparatus including a plasma etching apparatus, an apparatus for plasma-enhanced chemical vapor deposition, or an apparatus for plasma-assisted physical vapor deposition.

21. A method for improving the resistance of a substrate to plasma erosion and corrosion during plasma treatment, the method comprising the steps of: depositing a plurality of deposition layers by an atomic layer deposition (ALD) process to form a yttrium-containing anti-plasma coating on at least a portion of a substrate surface, such that the deposition layers having a first composition alternate with the deposition layers having a second composition, wherein, The deposited layer having the first component is a mixture film composed of a mixture of at least two compounds, one of which is yttrium oxide, and wherein the deposited layer having the second component is composed of a metal fluoride.

22. The method as described in claim 21, wherein, The deposited layer having the first component is a mixture film composed of a mixture of a first compound and a second compound, wherein the second compound is yttrium(III) (Y₂O₃) and the first compound is a metal oxide different from yttrium oxide, the metal oxide including either aluminum(III) (Al₂O₃) or zirconium(IV) (ZrO₂), and wherein the deposited layer having the second component is composed of yttrium(III) fluoride (YF₃).

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