To prevent contamination of semiconductor wafers, semiconductor manufacturing equipment and flat panel display manufacturing equipment made of high purity materials with low plasma erosion properties. During manufacturing, these materials are exposed to highly corrosive gases, particularly halogen-based corrosive gases such as fluorine and chorine-based gases. Materials in the processing equipment are required to have a high resistance to erosion. To address this need, ceramics coatings such as alumina and yttria have been applied. The most frequently used method in semiconductor technology to apply these coatings is thermal spray and all its variations. However, even these materials erode over leading to lower yield and costly down time.
Thus, there is a need for coatings with improved resistance to erosion. To meet these objectives, technologists have turned to development of various atomic layer deposition (ALD) processes to aid in the deposition of plasma-resistant coatings. Advantages of ALD-formed coatings include conformal, dense, and pinhole-free film or coating that can coat complex 3D shapes and high-aspect ratio holes.
However, current ALD processes do suffer some drawbacks. For example, when depositing multiple materials by current ALD processes, the materials are typically deposited in a laminate structure with well-defined layers of individual materials. The processes disclosed here provide a new ALD-based process that allows deposition of non-laminated, homogeneous mixed films or coatings of two or more materials on a substrate, such as a chamber component.
Accordingly, the inventions described herein address a further improvement over current processes for making plasma-resistant coating
Disclosed herein are methods for the deposition of a plasma resistant coating onto a substrate using an atomic layer deposition process. The process includes carrying out a an ALD deposition cycle that includes at least the steps of: providing an ALD reactant chamber with a substrate; pulsing into the chamber a first coating precursor (Coat1Pre); pulsing into the chamber a second coating precursor (Coat2Pre), substantially immediately after the completion of the pulse of Coat1Pre; purging the chamber; pulsing into the chamber a co-reactant precursor; and purging the chamber. At completion of a cycle, a monolayer is deposited. The monolayer is or is included in a mixed coating of substantial homogeneity.
The methods may be varied, e.g., the second or third steps can be repeated multiple times (1 to 4 times or 2 to 8 times). If one desired to prepare mixed coatings or more than two components, other steps may be added, e.g., at least one additional step of pulsing an additional metal precursor into the chamber substantially immediately after the completion of the pulse of the Coat1Pre or Coat2Pre. In such embodiments, the additional precursor(s) is not the same as Coat1Pre or Coat2Pre.
Also included within the invention are coatings made by the disclosed processes (such as those having, e.g., without limitation, the mixed composition of YxAlyOz, YxZryOz, YxOyFz, and YxAlyZrzOw, YxSiyOz) and substrates (articles) bearing such coatings.
The foregoing summary, as well as the following detailed description of preferred embodiments of the invention may be better understood when read in conjunction with the appended drawings. The invention is not limited to the precise arrangements and instrumentalities shown in the drawings. In the drawings:
The invention as described herein includes atomic layer deposition-based (ALD-based) methods of depositing non-laminate homogeneous coatings of two or more metal oxides, fluorides or nitrides (“mixed coatings”), the mixed coating itself and substrates bearing the mixed coatings.
Conventional ALD processes can be used to deposit multiple materials; however, such processes result in films or coatings having laminate structures with well-defined layers of individual materials. Theoretically, it is believed that a more uniform distribution of the selected multiple materials may result if a simultaneous deposition of the materials was used. However, many current ALD reactors do not permit this option. The processes described herein have been developed that permit use of a conventional ALD reactor to achieve deposition of non-laminated, homogeneous mixed coatings of two or more materials, i.e., one can prepare coatings in which two or more metal cations are present within the same monolayer.
In particular, the methods of the invention enable one to deposit metal oxides that have two or more metal cations within a single monolayer and ternary, quaternary or greater oxides of fixed stoichiometry while maintaining control over the structure and properties of the monolayer by immediately consecutive pulsing of the components' precursors in the ALD process.
In the practice of the inventive methods, one can vary the atomic ratio between or among the two or more metal cations to prepare structures specifically tailored to the end application in which the coatings will be used. Moreover, since the ALD method of the invention may be used to deposit materials with ternary, quaternary or greater structures, ALD deposition of garnet and perovskites materials becomes less of a technical challenge.
The processes, coatings and coating-bearing substrates of the invention in their various embodiments are useful to prepare and/or to coat substrates that form components useful in a variety of industries, especially those where components may be exposed to high temperatures, and/or corrosive chemicals. For example, the coatings of the invention may be used on components that are found in equipment/machines/devices used in aerospace, pharmaceutical production, food processing, oil field applications, military and/or maritime applications, industrial manufacturing, and scientific and/or diagnostic instrumentation.
The practice of the process includes a substrate to which the coating is applied. The substrate may be any material useful for the desired end applications. In some embodiments, one may prefer that the substrate is a non-ferrous metal, a non-ferrous metal alloy, a ferrous metal or a ferrous metal alloy. Suitable materials may include substrates of titanium, titanium alloys, nickel alloys, aluminum, nickel, ceramics, aluminum alloys, steels, stainless steel, carbon steel, alloy steel, copper, copper alloys, lead, lead alloys, ceramics, quartz, a glass, a polymer, such as a high performance polymer, and a fiberglass. The substrate may also combine materials, that is, a portion may be, for example, made of aluminum and an adjacent portion made of copper.
The coated substrate may make up or be part of a variety of components, such as, for example, components that are planar in nature or have a 3D geometry. For example, the component may be a chamber component, like a shower head, a chamber wall, a nozzle a plasma generation unit, a diffuser, a gas line interior, a chamber orifice, and the like.
As noted, the invention may be used in any sector of industry. However, a development focus of the invention included substrates in the semiconductor manufacture arena. In semiconductor manufacturing, the processes used expose semiconductor process chamber components to high temperatures, high energy plasma, a mixture of corrosive gases, and/or high-level stressors. Coating semiconductor process chamber components with protective coatings is an effective way to reduce defects and extend their use lifetime. As used herein, the term “chamber component” refers to a component used in a semiconductor manufacturing process chamber, such as, for example, a plasma etcher or plasma etch reactor, and a plasma cleaner. Without limitation, examples of these components include substrate support assemblies, wafer boats, electrostatic chucks, rings, chamber walls, chamber bases, gas distribution plates, gas lines, gas nozzles, portals, showerheads, lids, liners, shields, escutcheons, plasma screens, flow equalizers, cooling bases, fasteners, ports, etc.
Once the substrate is selected it is placed in the reaction chamber of an ALD tool. Any ALD tool may be used and they are commonly available, such as, for example, those available from Picosun (P-series and R-series ALD systems); Beneq Oy (TFS-series or P-series) Oxford Instruments (FlexAl and OpalAl ALD systems); and/or Veeco Instruments (Savannah, Fiji, and Phoenix ALD systems).
The method described herein is illustrated schematically in the flowchart of
With reference to
In alternative embodiments, one may wish to prepare a mixed coating more than two materials. In such instance, a pulse of a third coating precursor (“Coat3Pre”), a pulse of a fourth coating precursor (“Coat4Pre”), a pulse of a fifth coating precursor (“Coat5Pre”) fifth pulse, etc., may be introduced into the ALD reaction chamber sequentially and each substantially immediately after the previous pulse. Again, the pulses are applied consecutively; no purge of the reaction chamber is carried out in between the pulses. The precursors are not identical to one another, enabling the preparation of a 3-, 4-, 5-, etc., component coating.
After all desired coating precursors have been added to the reaction chamber, the chamber is purged, see
It is noted that the dose and purge times given above in ranges are merely illustrative. It is well within the skillset of a person of ordinary skill in the art to determine dose time and purges times for an ALD process. As in known in the art, ALD reactions are self-limiting. The ALD reaction must have optimized dosing concentrations and times plus optimized purge times for each of the precursors.
Following the purge of the coating precursors, a pulse of co-reactant precursor 8 is added. Such co-reactants include oxidizer precursors (to grow oxides), fluoride precursors (to grow fluorides), and/or nitride precursors (to grow nitrides). Specific examples include, without limitation, water, an H2O2, O2, O2 plasma, NH4F O3, H2O2, N2O, NO2, NO and mixtures of the same (oxidizer precursors), hydrogen fluoride (“HF”), HF-pyridine, (fluoride precursors), tetrakis(dimethylamino)titanium (TDMAT), NH3, H2N-NH2 (nitride precursor). Other examples are shown the table of
The reaction chamber is then purged 10 again in a manner as described above. This process, described by the process blocks 2, 4, 6, 8, 10 in
In an embodiment, the substrate is pretreated by cleaning or heating before beginning the process. Additionally, one may wish to deposit a preliminary or primer layer on the substrate before initiating the above-described process. The primer layer may be a metal oxide layer, for example, aluminum oxide. It may be formed by any process including, for example, ALD, anodization, thermal spray, sputtering, vapor deposition and evaporation techniques.
Also, one may subject the coating to an annealing step as is known or developed in the art. In some embodiments, the deposited mixed homogeneous film may be annealed in order to transform the film from amorphous to a crystalline phase. For example, it may be desired to transform the as deposited, amorphous YAlO3 film into an yttrium aluminum oxide perovskite or, in a different formulation, convert the amorphous Y3Al5O12 into a crystalline Y3Al5O12 garnet. Amorphous YxSiyOz can be thus converted into various crystalline phases of yttrium silicates with the same approximate chemical formula. Annealing may also take place in an oxygen atmosphere with the motivation to reduce oxygen vacancies. Another reason for post-deposition annealing is to dry the film of residual excess water that may be stored within the structure of the coating.
The coating precursors selected for use in the preparation of the coating will vary depending on what components on wishes to have mixed in the monolayer(s). Any known or developed for use in the ALD arts may be used. Examples include without limitation, those in
In an embodiment of the method, the coating includes at least one monolayer that is a mixed composition of YxAlyOz, or YxAlyZrzOw. In such embodiment, one may use trimethyl aluminum as one of the precursors from which the monolayer is grown.
The invention also encompasses the coatings and films prepared by the methods, and substrates, articles or components that have surfaces that are coated or bear the coating, either wholly or in part. The multi-component coating prepared as disclosed herein may be a coating having multiple different oxides, multiple different fluorides, or a combination of one or more oxides and one or more fluorides.
Specifically, the coating was deposited by pulsing an yttrium precursor one time, followed substantially immediately by the pulsing of an aluminum precursor one time, followed by a purge, then an oxidative pulse and a second purge. This was retreated for 384 super cycles.
In various embodiments, the resulting mixed coating includes at least one monolayer having a composition that is one of YxAlyOz, YxZryOz, YxOyFz, YxAlyZrzOw, and YxSiyOz.
In additional or alternative embodiments, the mixed coating may contain at least two materials selected from aluminum oxide, yttrium oxide, a lanthanide series element oxide or fluoride, zirconium oxide, hafnium oxide, binary, ternary or quaternary metal oxides containing at least one rare earth metal, Y2O3, La2O3, HfO2, Ta2O5, Er2O3, ZrO2, Y3Al5O12 (YAG), Er3Al5O13 (EAG), Y4Al2O9 (YAM), YAlO3 (YAP), Er4Al2O9 (EAM), ErAlO3 (EAP), fluorides of yttrium, zirconium, hafnium and mixtures of the same.
The mixed coating may be any thickness; desired thicknesses will vary depending on the end application in which the coating or coated substrate (article) is to be used. The thickness of the coating can be varied by increasing or decreasing the number of monolayers deposited to form the coating, e.g., about 1 to about 100,000, about 1 to about 5000, and about 1 to about 1000.
As an example, the coating may have a thickness of about 10 to about 10,000 nanometers of about 30 to about 100 nanometers and/or of about 40 to about 60 nanometers. In an embodiment, the mixed coating comprises a structure that is amorphous.
A 39.5 nm YxAlyOz plasma etch-resistant coating was deposited on the surface of a silicon substrate shown in
YxAlyOz was deposited using tris-(methylcyclopentadienyl) yttrium precursor, trimethyl aluminum (TMA), and water as the co-reactant. The yttrium precursor vessel temperature was set at 145° C., while the TMA and the water vessel temperatures were both set at 22° C.
The recipe starts by a short (8×) half-cycle of water pulsing (0.2 seconds)/purging (24.0 seconds) for the hydroxylation of the Si wafer surface. The pulsing/purging scheme for the deposition of YxAlyOz, monolayers was structured in the following sequence: a 0.3 seconds yttrium precursor vapor pulse followed by a 0.3 seconds aluminum precursor vapor pulse, and then purging of the 2 different metal precursors through a nitrogen purge step of 18.0 seconds. This was followed by a 0.2 second water vapor pulse and by a second nitrogen purge step of 18 seconds. This sequence of steps was repeated for 384 cycles to build up a 46 nm thick layer of Y2O3. The recipe ends with a short (4×) half-cycle of water pulsing (0.2 seconds) / purging (24.0 seconds) for the hydroxylation of the ternary oxide coating surface.
The resulted coating was amorphous in structure due to the aluminum oxide contribution and was close to a targeted 1/1 atomic ratio between the two metal cations.
A YxAlyOz plasma etch-resistant coating was deposited on the surface of a silicon substrate in a standard cross-flow type ALD reactor. A 50 nm silicon wafer substrate was placed in the middle slot of a wafer holder placed inside the ALD reactor. The reactor was then pumped down by a vacuum pump while purging with nitrogen to a pressure of 0.3 hPa. The temperature of the reaction chamber was set to 250° C. The flow rates through the reactor line and the precursor delivery lines were set as in Example 1.
YxAlyOz was deposited using tris-(methylcyclopentadienyl) yttrium precursor, trimethyl aluminum (TMA), and water as the co-reactant. The yttrium precursor vessel temperature was set at 145° C., while the TMA and the water vessel temperatures were both set at 22° C.
The process initiates by a (8×) half-cycle of water pulsing (0.2 seconds)/purging (24.0 seconds) for the hydroxylation of the silicon substrate surface. Subsequently, pulsing/purging scheme was of the following sequence: a 1.4 seconds yttrium precursor vapor pulse followed by a 0.3 seconds aluminum precursor vapor pulse, and then purging of the 2 different metal precursors through a nitrogen purge step of 18.0 seconds. This was followed by a 0.2 second water vapor pulse and by a second nitrogen purge step of 18 seconds. This sequence of steps was repeated for 2,184 cycles to build up the layer. The coating prepared had a thickness of about 253 nm and was amorphous in structure, as confirmed by the data obtained via grazing incidence X-ray diffraction (GIXRD) analysis, shown in
The Rutherford Backscattering (RBS) data shown in the table of
A YxAlyOz plasma etch-resistant coating was deposited on the surface of a silicon substrate in a standard cross-flow type ALD reactor. A 50 nm silicon wafer substrate was placed in the middle slot of a wafer holder placed inside the ALD reactor. The reactor was then pumped down by a vacuum pump while purging with nitrogen to a pressure of 0.3 hPa. The temperature of the reaction chamber was set to 250° C. The flow rates through the reactor line and the precursor delivery lines were set as in Example 1.
YxAlyOz was deposited using tris-(methylcyclopentadienyl) yttrium precursor, trimethyl aluminum (TMA), and water as the co-reactant. The yttrium precursor vessel temperature was set at 145° C., while the TMA and the water vessel temperatures were both set at 22° C.
The process initiates by a (8×) half-cycle of water pulsing (0.2 seconds)/purging (24.0 seconds) for the hydroxylation of the silicon substrate surface. Subsequently, pulsing/purging scheme was of the following sequence: a 0.8 second yttrium precursor vapor pulse followed by a 0.3 seconds aluminum precursor vapor pulse, and then purging of the 2 different metal precursors through a nitrogen purge step of 18.0 seconds. This was followed by a 0.3 second water vapor pulse and by a second nitrogen purge step of 18 seconds. This sequence of steps was repeated for 2,432 cycles to build up the layer. The coating prepared had a thickness of about 257 nm and was amorphous in structure, as confirmed by the data obtained via grazing incidence X-ray diffraction (GIXRD) analysis, shown in
The Rutherford Backscattering (RBS) data shown in the table of
A YxAlyOz plasma etch-resistant coating was deposited on the surface of a silicon substrate in a standard cross-flow type ALD reactor. A 100 nm silicon wafer substrate was placed in the middle slot of a wafer holder placed inside the ALD reactor. The reactor was then pumped down by a vacuum pump while purging with nitrogen to a pressure of 0.3 hPa. The temperature of the reaction chamber was set to 250° C. The flow rates through the reactor line and the precursor delivery lines were set as in Example 1.
YxAlyOz was deposited using tris-(methylcyclopentadienyl) yttrium precursor, trimethyl aluminum (TMA), and water as the co-reactant. The yttrium precursor vessel temperature was set at 145° C., while the TMA and the water vessel temperatures were both set at 22° C.
The process initiates by a (8×) half-cycle of water pulsing (0.2 seconds)/purging (24.0 seconds) for the hydroxylation of the silicon substrate surface. Subsequently, pulsing/purging scheme was of the following sequence: a 0.2 second yttrium precursor vapor pulse followed by a 0.3 second aluminum precursor vapor pulse, and then purging of the 2 different metal precursors through a nitrogen purge step of 18.0 seconds. This was followed by a 0.2 second water vapor pulse and by a second nitrogen purge step of 18 seconds. This sequence of steps was repeated for 8000 cycles to build up the layer. The coating prepared had a thickness of about 813 nm and was amorphous in structure, as confirmed by the data obtained via grazing incidence X-ray diffraction (GIXRD) analysis.
It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims.
This application claims the benefit of priority under 35 USC 119(e) to U.S. Provisional Application Ser. No. 63/044,185, filed Jun. 25, 2020, the contents of which are incorporated herein by reference.
Number | Date | Country | |
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63044185 | Jun 2020 | US |