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. There is now emerging plasma-resistant coatings deposited by ALD. Advantages of ALD include conformal, dense, and pinhole-free film that have the ability to coat complex 3D shapes and high-aspect ratio holes. The inventions described herein address a further improvement over current plasma-resistant coating and films and may be prepared using an atomic layer deposition process.
The invention described herein includes high performance multi-layer coatings, and methods of depositing such coatings, and components and equipment that bears such coatings.
While much of the description provided herein addresses use of the coatings in the semiconductor processing arena (e.g., where the coatings are exposed to plasma gases), it is contemplated that the methods and coatings of the invention can be used advantageously in any end application that involves high temperature and/or corrosive environments and related uses. Examples include without limitation, microchip device fabrication for transistor components (gate oxide, metal gate, etc.) and memory components, laminates for barrier layer applications in anti-corrosion, thermal protection, electrical insulator layers, hydrophobic surfaces, etc, electroactive layers for architectural coatings on large planar glass substrates, photovoltaic solar cell layers with defined functional roles, rechargeable batteries layered cathodes and electrolyte layers, solid oxide fuel cell membranes, optical coatings, biocompatible layers for implants, sensors and detectors with layered structure, 2-D layers with specific functional roles, planar junctions, bi-, and multi-component heterogeneous catalysts.
The invention includes a methods of providing a multi-layer coating to a surface of a substrate that includes forming an anchor layer by controlled oxidation of the surface of the substrate (Me1Oxide); depositing on the anchor layer a glue layer comprising an amorphous or crystalline first metal oxide (Me1Oxide); forming on the glue layer a graded laminate layer containing the first metal oxide (Me1Oxide) and a second metal oxide (Me2Oxide), and having a gradient with an increasing content of the second metal oxide (Me2Oxide) and a decreasing content of the first metal oxide (Me1Oxide) such that a lowermost stratum of the graded laminate layer immediately adjacent to the glue layer contains no more than about 0.1 mol % to about 49 mol % of the second metal oxide (Me2Oxide) and an uppermost stratum of the graded laminate layer immediately adjacent to an external layer contains no more than about 0.1 mol % to about 49 mol % of the first metal oxide (Me1Oxide); and depositing on the graded laminate layer the external layer comprising the second metal oxide (Me2Oxide).
In an embodiment, each of the anchor layer, the glue layer, the graded laminate layer and/or the external layer may be independently formed and/or deposited using an atomic layer deposition process.
Also included are methods of using the concept described above for suppressing, inhibiting, or eliminating growth of certain crystalline phases and/or structures oxides, using an interrupt layer.
The interrupt layer may contain at least two or at least three sublayers deposited sequentially, one upon the next, using an atomic layer deposition process: i) a first interrupt sublayer that is a graded laminate sublayer containing Me1Oxide and Me2Oxide, wherein the first graded laminate sublayer has a gradient with an increasing content of the first metal oxide (Me1Oxide) and a decreasing content of the second metal oxide (Me2Oxide) such that a lowermost stratum of the first graded layer immediately adjacent to the second metal oxide Me2Oxide coating layer contains no more than about 0.1 mol % to about 49 mol % of the first metal oxide (Me1Oxide) and an uppermost stratum of the first graded layer immediately adjacent to a second sublayer contains no more than about 0.1 mol % to about 49 mol % of the second metal oxide (Me2Oxide); ii) a second interrupt sublayer containing Me1Oxide in an amount of about 100 mol %; and iii) a third interrupt sublayer that is a graded laminate layer containing Me1Oxide and Me2Oxide wherein the second graded laminate sublayer has a gradient with an increasing content of the second metal oxide (Me2Oxide) and a decreasing content of the first metal oxide (Me1Oxide) such that a lowermost stratum of the interrupt layer immediately adjacent to the second sublayer layer contains no more than about 0.1 mol % to about 49 mol % of the second metal oxide (Me2Oxide) and an uppermost stratum of the interrupt layer immediately adjacent to a second Me2Oxide coating layer contains no more than about 0.1 mol % to about 49 mol % of the first metal oxide (Me1Oxide); and depositing on the interrupt layer a second Me2Oxide coating layer containing Me2Oxide in an amount of about 100 mol % using an atomic layer deposition process to a thickness of 1-1000 nm. If the interrupt layer contains only two sublayers, the middle layer is omitted. Further, in some embodiments, more than one interrupt layer may be present.
At least one drawing or image executed in color and/or a photograph is included herein. Copies of this patent or patent application publication with color drawings and photographs will be provided by the Office upon request and payment of the necessary fee.
The present disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that different references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. In the drawings:
The invention described herein include methods of providing a multi-layer coating to a surface of a substrate, substrates and/or articles coated or provided with such films, including for example, semiconductor processing components and equipment. Also included are related methods of reducing disruptive forces present at an interface between two metal oxide layers and methods of inhibiting unwanted crystalline growth (e.g. columnar) and/or a crystalline phase in an atomic layer deposition process.
The invention as described herein allows for preparation of a plasma resistant multi-layer coating that exhibits excellent bonding of the film to a substrate by virtue of a series of layers of varying materials that create a gradual chemical transition. In addition, in some embodiments, the presence of the graded laminate layer as described infra allows for greater film adhesion and resistance to partial etching of the multi-layer coating over time when used on semiconductor process equipment piece and renders any post-deposition annealing step for layer inter-diffusion purposes obsolete. It therefore permits creation of crystalline films with highly controlled structure or amorphous films with a high degree of homogeneity or even perfectly homogeneous amorphous films.
In other embodiments, the multi-layer coatings and processes of the invention may be used 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 multi-layer 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.
With reference to
The substrate 10 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, aluminum, nickel, ceramics, aluminum alloys, steels, stainless steel, carbon steel, alloy steel, copper, copper alloys, lead, lead alloys, ceramics, quartz, silicon, 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.
The multi-layered coating 10 may include an anchor layer 18 that is adjacent to the substrate 12. When the substrate 12 selected is a metal, the anchor layer 18 is an oxide of the metal created by a controlled oxidation process carried out at the surface of the substrate. For example, if the substrate is aluminum, the anchor layer may be made up of Al2O3, AlOx, and/or mixtures of the same, developed at surface by controlled anodization. The anchor layer oxide may be developed by exposing the clean substrate surface to ozone, O2, O2 plasmas, H2O2, N2O, NO2, NO, and mixtures of the same. The anchor layer oxide may be developed in-situ or ex-situ the ALD chamber by exposing the substrate surface to ozone, O2, O2 plasmas, H2O2, N2O, NO2, NO, acid attack or electrolytic/electroless anodization. The anchor layer provides linkage via chemical (not physical) bonding to the substrate and the remainder of the coating layer.
Development of the oxide to form the anchor layer may be carried out by a variety of processes well known in the art and generally at temperatures of about 21° C. to about 800° C. If the remaining layers of the multi-layer coating are to be deposited via an atomic layer deposition process (“ALD Process”), the step of developing the anchor layer may be carried out in the ALD tool using the established protocols of the specific tool.
In most embodiments, it may be preferred that the anchor layer 18 is as uniform and continuous along the entire surface of the substrate as is possible. In general, the thickness of the anchor layer may vary, depending on the end application of the coated substrate and/or the overall intended thickness of the multi-layer coating. In many embodiments, the anchor layer has a thickness of about 0.1 to about 100 nanometers; of about 1 to about 50 nanometers; of about 5 to about 35 nanometers and of about 10 to about 20 nanometers. In embodiments, the layer may be up to 1 micron or more, e.g., in some instances up to several hundred microns.
In embodiments where the selected substrate is non-metallic, e.g., quartz, polymer, glass, and the like, the anchor layer 18 may be omitted from the multi-layered coating of the invention.
On top of the anchor layer, if present, the multi-layered coating may include a glue layer 20 that is made of a first metal oxide in an amorphous or crystalline state, followed by a graded laminate, and an external layer. The graded laminates, for reasons explained in more detail infra, provide a controlled gradual change in composition from the metal oxide surface of the glue layer to the external layer resulting in increased adherence and durability of the coating overall. The external layer, in a finished product, is exposed to an environment such as the interior of a reaction or etching chamber and is resistant to degradation by plasmas. In a preferred embodiment, each of the glue layer, the graded laminate layer and the external layer are deposited using an ALD process. Such processes can be carried out using commercially available ALD tools, process protocols and chemical precursors (metal and non-metal), 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).
In an embodiment, to prepare a multi-layer coating of the invention, one selects a substrate as described above. Referencing the
The cleaned substrate is then treated so that an anchor layer of metal oxide is grown on the surface. This may be accomplished by exposure to ozone, O2, O2 plasmas (precursor H2O), H2O2, N2O, NO2, NO, and mixtures of the same which provides for a controlled formation of a metal oxide on the surface of the substrate. The metal oxide forms depends on the constituent of the substrate; an aluminum substrate develops an anchor layer of aluminum oxide; a titanium substrate develops an anchor layer of titanium oxide, etc. See,
Using an ALD process, a glue layer is deposited on the anchor layer. See,
As is known to a person of skill in the art, a layer formed by ALD is made up of one or more monolayers of a metal oxide, where each monolayer is laid down by one reaction cycle carried out within the ALD tool chamber. The glue layer of the invention may be composed of any number of monolayers desired. The number of monolayers will necessarily vary depending on the thickness one wishes to be in the end application. It may be preferred that the glue layer is composed of about 1 or 2 to about 1000 monolayers, about 100 to 700 monolayers and/or about 300 to about 500 monolayers.
By way of example,
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.
In various embodiments, either both of the purge steps can be accomplished using argon, or any other inert gas(es) in place of or mixed with nitrogen.
The thickness of the glue layer may be variable and may in some embodiments, be up to an including about a micron in thickness. In some embodiments, it may be preferred that the thickness is 0.1 to about 100 nanometers, about 1 to about 50 nanometers, about 5 to about 35 nanometers and about 10 to about 20 nanometers.
Once the glue layer has been formed to desired thickness, a graded laminate layer is deposited. See,
It is hypothesized that the presence of the graded laminate layer allows for greater resistance to partial etching of the external layer when in use over time. This resistance can be in the form of lower etch rate and/or more durable film (for example, reduced potential for film delamination). Another advantage of the presence of the graded laminate layer is that it makes the post-deposition annealing step of the coating obsolete and thus may yield amorphous films with a high degree of homogeneity or potentially perfectly homogeneous amorphous films. The graded laminate layer in combination with the anchor layer also provides for excellent bonding of the plasma-resistant film to the substrate.
In general terms, the graded laminate layer is compositionally constructed so that adjacent to the glue layer, the graded laminate layer is rich in the metal oxide of the glue layer and poor in the oxide of the external layer. Conversely, the portion of the graded laminate layer that is adjacent to the external layer is rich in the metal oxide of the external layer, but poor in the metal oxide of the glue layer, that is, the graded laminate layer included both a first metal oxide and a second metal oxide and has an increasing content of the second metal oxide and a decreasing content of the first metal oxide as it transitions towards the external layer, which is composed of the second metal oxide. This is illustrated schematically below, where Me1 and Me2 each represent a different metal, such as for example, titanium, aluminum, and/or yttrium:
Accordingly, with reference to the schematic above and to
The “uppermost stratum” and the “lowermost stratum” may be independently composed of any number of monolayers. In most embodiments, the “uppermost stratum” and the “lowermost stratum” are independently each composed of about 1 to about 500 monolayers, preferably about 50 to 100 monolayers wherein each monolayer is formed by one cycle of an ALD process.
Latitudinal symmetry of the graded laminate layer 16 may be desired in some embodiments, but is not required; that is, for example, with reference to the cross sectional view presented in
Referencing
The one or more intermediate strata may each individually contain any mole ratio of the Me1Oxide to the Me2Oxide, so long as the overall compositional gradient structure of the graded laminate layer is maintained. Variation of the ratio of the oxides among the layers permits preparation of grade layers having steep transitions, gradual transitions and/or intermediate tractions.
In the example of
Each stratum may be prepared by any means in the art, although various atomic layer deposition processes may be preferred.
In an exemplary method, each strata is prepared by depositing sequential sublayers, each sublayer containing 100% of the first oxide or the second oxide, where X is the number of sublayers of Me1Oxide and Y is the number of sublayers of Me2Oxide, and the ratio of X to Y is representative of the ratio of Me1Oxide:Me2Oxide (by % mol) desired in the specific stratum. When the various strata are assembled together, this provides for a compositionally binary stratum which nonetheless maintains the desired ratio of metal oxides.
In many embodiments, it is preferred that X and Y are divided by a common denominator, preferably the largest common denominator, to reduce the number of sublayers one needs to prepare while maintaining the desired overall Me1Oxide:Me2Oxide ratio in the stratum. For example, if a 70:30 ratio is targeted, one could deposit 70 sublayers of a first oxide and 30 sublayers of a second oxide, but, in most embodiments, one may prefer to deposit 7 sublayers of a first oxide and 3 sublayers of a second oxide; either option maintains the overall desired molar ratio of the stratum.
In another similar example, to prepare the lowermost stratum 28 of
In preferred embodiments, the sublayers of the strata are deposited in an order that provides the greatest symmetrical arrangement of the sublayers within the overall strata. Referencing
This arrangement presents the greatest symmetry, even though there are an odd number of “A” layers present.
In an alternative embodiment, instead of creating compositional binary film a by alternating deposition of metal oxides, the sublayers of each strata can be created by co-depositing two metal precursors simultaneously into the reaction chamber so that the Me1Oxide and Me2Oxide are co-formed in the sublayer creating a homogenous composition having the desired Me1Oxide:M2Oxide ratio.
In this version of the process, the strata are prepared by the co-deposition of the Me1Oxide and Me2Oxide using an ALD process that includes simultaneous exposure of the reaction surface to at least two different precursors.
In addition, it should be appreciated that the graded laminate layer can contain more than two components in a compositional gradient in various embodiments. For example, one may prepare a 3-component gradient layer having Me1Ox, Me2Ox and Me3Ox. If, for purposes of example, 1=Al, 2=Y and 3=Zr), the layer's sequence may be as follows:
If the underlying layer is Al2O3 (Me1Ox), the sequence above continues with the following unit: CGL(Me1Ox, Me2Ox)-Me2Ox-CGL(Me2Ox, Me3Ox)-Me3Ox-CGL(Me3Ox, Me1Ox)-Me1Ox (where “CGL” stands for compositional gradient layer).
By way of example, one may prepare a 4-component graded laminate layer having Me1Ox, Me2Ox, Me3Ox and Me4Ox. In an example, 1=Al, 2=Y, 3=Zr and 4=Er and the graded laminate layer has the following sequence:
If the underlying layer is Al2O3 (Me1Ox), the sequence above continues with the following unit: CGL(Me1Ox, Me2Ox)-Me2Ox-CGL(Me2Ox, Me3Ox)-Me3Ox-CGL(Me3Ox, Me4Ox)-Me4Ox-CGL(Me4Ox, Me1Ox)-Me1Ox.
As in all of the graded laminate layers disclosed herein, the first oxide to be mentioned starts rich and ends poor, while the second oxide to be mentioned starts poor and ends up rich.
Once the graded laminate layer is completed, an external layer is deposited. Retuning to
In an embodiment, this external layer can be followed by the deposition of a second graded laminate layer identical to that described above except for the compositional gradient between Me2Oxide and Me1Oxide is reversed. See,
This second graded laminate layer may be followed by deposition of an additional layer, preferably by an ALD process, composed of 100 mol % Me2Oxide, see
With reference to
In such arrangement, the slope of the lines forming the peaks/valleys will vary depending on the steepness or mildness of the gradient with the layer. See also,
With reference to the
With reference to
With reference to
Referencing
In an embodiment, a layer of the invention that is a laminate of Y2O3 and HfO2, may be prepared on a nickel substrate. An anchor layer of NiO is grown in situ on the surface of the substrate via oxidation by ozone or another oxidizer. A glue layer of NiO is deposited by ALD on the anchor layer. The 3rd step is a CGL that makes the transition from NiO to Y2O3 (or the other oxide HfO2, depending which one choose to start the film). The NiO/Y2O3 CGL starts NiO-rich and Y2O3-poor and ends up NiO-poor and Y2O3-rich. The 4th step is ALD deposition of a Y2O3 block. The 5th step is a CGL that starts Y2O3-rich and HfO2-poor and ends up Y2O3-poor and HfO2-rich. The 6th step is the ALD deposition of a HfO2 block. The 7th step is a CGL that is non-superimposable and the mirror image of the CGL in step 5. The 8th step is the same as step number 4, so a cycle of steps 4 through 7 builds up the main structure of the film.
Alternatively in another embodiment, the invention includes a method of preventing, suppressing or eliminating the formation or growth of crystalline structure in an amorphous first metal oxide (Me1Oxide) coating, or it can be used for preventing, suppressing or eliminating the unwanted growth phase or structure in a crystalline oxide single phase. Another use is to force an amorphous structure in an otherwise thermodynamically and kinetically stable crystalline metal oxide. As is known in the art, certain oxides, such as for example yttrium oxide, have a tendency to switch from cubic phase growth to monoclinic phase growth as it is being deposited to form a film or coating. Also, for the thermodynamically stable cubic phase of yttrium oxide, undesired columnar growth can become after a certain large enough thickness is achieved.
These behaviors can limit one's ability to prepare a uniform successful film of a greater thickness. The inventive process provides an interrupt layer which is disposed intermittently between the desired Me2Oxide coating layers. Implementation of this process permits suppression or elimination of the growth or transition of a second metal oxide in a coating from desired amorphous form to the thermodynamically stable monocrystalline form, even as the temperature the film is subjected, is ramped up.
In an embodiment of this method, Me1Oxide and Me2Oxide are not the same and may be, for example, Y2O3, Al2O3 or any of the other oxide options using any of the precursors in any combination detailed above.
The interrupt layer in this embodiment of the invention includes at least three interrupt sublayers, each of which is deposited, one on the other, in the sequence described herein. Preferably an atomic layer deposition process is used to lay down each sublayer.
With reference to
(i) A first interrupt sublayer 40 that is a graded laminate sublayer, prepared in the manner described supra with respect to the graded laminate layers. The graded laminate sublayer 40 of this embodiment contains each of Me1Oxide and Me2Oxide in a gradient with an increasing content of the first metal oxide (Me1Oxide) and a decreasing content of the second metal oxide (Me2Oxide) such that a lowermost stratum 46 of the first graded layer immediately adjacent to the first Me2Oxide coating layer 36 contains no more than about 0.1 mol % to about 49 mol % of the first metal oxide (Me1Oxide). Conversely, an uppermost stratum 48 of the first graded laminate sublayer 40 that is immediately adjacent to a second sublayer 42 contains no more than about 0.1 mol % to about 49 mol % of the second metal oxide (Me2Oxide).
(ii) A second interrupt sublayer 42 containing Me1Oxide in an amount of about 100 mol %.
(iii) A third interrupt sublayer 44 that is a graded laminate sublayer containing Me1Oxide and Me2Oxide. The third interrupt sublayer 44 has a gradient with an increasing content of the second metal oxide (Me2Oxide) and a decreasing content of the first metal oxide (Me1Oxide) such that a lowermost stratum 66 of the third interrupt layer that is immediately adjacent to the second sublayer layer contains no more than about 0.1 mol % to about 49 mol % of the second metal oxide (Me2Oxide). Conversely, an uppermost stratum 68 of the third interrupt sublayer 44 that is immediately adjacent to a second Me2Oxide coating layer 70 contains no more than about 0.1 mol % to about 49 mol % of the first metal oxide (Me1Oxide).
Deposited on this 3-part interrupt layer 38 is second Me2Oxide coating layer 70 that is preferable 100 mol % Me2Oxide. This sequence may be repeated an infinitum until a desired thickness of the Me2Oxide-based coating is achieved.
Because the graded laminate layers (and sublayers) are formed as laminates using “stacked” strata the invention allows for great flexibility with respect to the rate of transition for the graded layers or sublayers, which in turn provides for the production of an infinite variety of coatings with varying physical and chemical properties.
Also included within the scope of the invention are any coatings prepared by any of the methods described supra, substrates and/or components that bear multi-layer coatings prepared by any of the methods described supra, equipment or devices that contain any of such components and/or multi-layer coatings.
An in situ layer of AlOx was grown out of the freshly cleaned surface of an aluminum substrate, by oxidation with ozone in a in a standard cross-flow type ALD reactor as follows.
An aluminum substrate of a one inch diameter and 0.25 inches thick was placed in a reactor chamber. The chamber had a temperature of 400 degrees C. and the pressure inside the reactor was at 0.4 hPa. A mixture of 19% ozone in oxygen was delivered into the chamber at a flow rate of 150 sccm. The process employed 400 cycles of ozone pulsing for 2 seconds and purging for 18 seconds. The resulting AlOx anchor layer grown was approximately 640 nm thick. A micrograph of the resulting anchor layer in cross section is shown in
This example provides a illustrative process to prepare a “classic”, “generic” composition gradient layer film for two component compositions. Use of the CGL blocks ensures an improved interface and transition between the pure blocks of the two different materials. The formulation is predicted to offer a high degree of homogeneity for the 2 Component Laminate films, with direct outcome in the form of maximum resistance to delamination, scratching, mechanical stress testing, etc.
A 850 nm Y2O3/AlOx plasma etch-resistant film having two units or layers, each consisting of four blocks or monolayers and terminated with a capping block/monolayer of Y2O3 was formed on the surface of a silicon substrate as shown in
A 200 mm silicon wafer substrate was placed into a reaction chamber of an ALD reactor. The reactor was then pumped down with a vacuum pump while purging with nitrogen to a pressure of 0.4 hPa. The temperature of the reaction chamber was set to 250 degrees C. The flow rates through the delivery lines were all 150 sccm.
Y2O3 was deposited using tris-(methylcyclopentadienyl) yttrium precursor and water as the co-reactant. The yttrium precursor was heated to 145 degrees C. and water cooled to 22 degrees C. The pulsing sequence for the Y2O3 layers was deposited as follows: (a) A 2 second yttrium precursor vapor pulse followed by nitrogen purge step of 12 seconds followed by a 0.1 second water vapor pulse followed by a second nitrogen purge step of 18 seconds. This sequence of steps was repeated for 600 cycles to build up a 100 nm thick layer of Y2O3.
Y2O3 was used to create the YAlOx CGL blocks along with AlOx employing the same pulsing parameters described above.
AlOx was deposited using trimethyl aluminum (TMA) precursor and water as the co-reactant. The TMA precursor was cooled to 22 deg. C and water cooled to 22 deg. C. The pulsing sequence for AlOx was as follows: a 0.3 second TMA precursor vapor pulse followed by nitrogen purge step of 12 seconds followed by a 0.2 second water vapor pulse followed by a second nitrogen purge step of 18 seconds. This sequence of steps was repeated for 1,000 cycles to build the 110 nm block.
AlOx was used to create the YAlOx CGL blocks along with Y2O3 employed the same pulsing parameters described above. The structure of the film is described below.
The first layer deposited on to the silicon wafer was 250 nm of pure Y2O3. Next, a CGL YAlOx layer was formed by combining the Y2O3 and AlOx pulsing schemes described above in varying ratios. The first layer of the YAlOx layer deposited on the initial pure Y2O3 layer started with a ratio of nine Y2O3 cycles to one AlOx cycle for a total of 10 cycles.
Next the Y2O3/AlOx ratio was changed to 8:2, respectively, for a total of 10 cycles. This trend in the sequence then continued until the ratio was 1:9.
This then was followed by a third layer consisting of 110 nm layer of pure AlOx. The fourth layer was a CGL YAlOx layer and this started with a ratio of nine AlOx cycles to one Y2O3 cycle, for a total of 10 cycles. Next the AlOx/Y2O3 ratio was changed to 8:2, respectively, for a total of 10 cycles. This trend in the sequence then continued until the ratio was 1:9. This sequence of four steps was repeated twice and then a 100 nm capping layer of pure Y2O3 terminated the film.
The resulting film and aspects of the film are shown in
A 1.1 um Y2O3 plasma etch-resistant film with three interrupt layers was formed on the surface of a silicon substrate shown in a standard crossflow type ALD reactor.
To accomplish this, a 200 mm silicon wafer substrate was placed into a reaction chamber of an ALD reactor. The reactor was then pumped down with a vacuum pump while purging with nitrogen to a pressure of 0.4 hPa. The temperature of the reaction chamber was set to 250 deg. C. The flow rates through the delivery lines were all 150 sccm.
Y2O3 was deposited using tris(methylcyclopentadienyl)yttrium precursor and water as the co-reactant. The yttrium precursor was heated to 145 deg. C. and water cooled to 22 degrees C. The pulsing sequence for the Y2O3 was as follows: A 2 second yttrium precursor vapor pulse followed by nitrogen purge step of 12 seconds followed by a 0.1 second water vapor pulse followed by a second nitrogen purge step of 18 seconds. This sequence of steps was repeated for 1440 cycles to build up a 255 nm thick layer of Y2O3.
Y2O3 was used to create the YAlOx CGL interrupt layers along with AlOx employing the same pulsing parameters described above.
AlOx was used to create the YAlOx CGL interrupt layers; it was deposited using trimethyl aluminum (TMA) precursor and water as the co-reactant. The TMA precursor was cooled to 22 degrees C. and water cooled to 22 deg. C. The pulsing sequence for AlOx was as follows: a 0.3 second TMA precursor vapor pulse followed by nitrogen purge step of 12 seconds followed by a 0.2 second water vapor pulse followed by a second nitrogen purge step of 18 seconds. This sequence of steps was used to build the CGL interrupt layer described below.
The first layer deposited on to the silicon wafer was 250 nm of pure Y2O3. Next, a CGL YAlOx interrupt layer was formed by combining the Y2O3 and AlOx pulsing schemes described above in varying ratios.
The first sublayer of the YAlOx interrupt layer deposited on the initial pure Y2O3 layer started with a ratio of nine Y2O3 cycles to 1 AlOx cycle for a total of 10 cycles. Next the Y2O3/AlOx ratio was changed to 8:2, respectively, for a total of 10 cycles. This trend in the sequence then continued until the ratio was 1:9, respectively, at which point the scheme was reversed until the Y2O3/AlOx ratio reached 9:1, respectively, again. The reversal of the sequence starts a second sublayer of the YAlOx interrupt layer, and this is the mirror image of the first sublayer of the CGL YAlOx interrupt layer. This then was followed by another 250 nm layer of Y2O3. The YAlOx interrupt layer followed by 250 nm pure Y2O3 layer was repeated 2 more times to build a 1 um film stack.
A micrograph of a cross section of the resultant coating is shown in
An exemplary coating of the invention was created containing an anchor layer, a glue layer, an AlOx+CGL layer and final yttrium-aluminum oxide overlay. First, an in situ layer of AlOx was grown out of the freshly cleaned surface of an aluminum substrate as described in Example 1 herein.
Next the reaction chamber was cooled to 250° C. and a 40 nm layer of aluminum oxide (AlOx) was deposited using 400 ALD cycles to form a strong adhesion layer (glue layer) for the rest of the film. The AlOx glue layer was deposited at 250° C. with tri-methylaluminum (TMA) and water by ALD. The glue layer film becomes part of the substrate on which the rest of the film is deposited.
Following deposition of the AlOx glue layer, a CGL YAlOx interrupt layer was formed by combining the Y2O3 and AlOx pulsing schemes as described in previous examples in varying ratios. The first layer of the YAlOx layer deposited on the initial pure AlOx glue layer started with a ratio of twenty-nine AlOx cycles to one Y2O3 cycle. The next layer was deposited with twenty-eight cycles of AlOx and two cycles of Y2O3. This trend continued until an AlOx/Y2O3 cycle ratio of 1 to 29 was reached.
Next a 20 nm layer of Y2O3 was deposited using parameters described in Examples 2 & 3. This was followed by a 16 nm CGL layer was used to transition from 100% Y2O3 to a mixed Y/Al oxide. Finally, a generic 820 nm yttrium-aluminum oxide film was grown on top.
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 under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No.62/750,628, filed Oct. 25, 2018, entitled, “Plasma Resistant Multi-Layer Coatings and Methods of Preparing Same,” the entire disclosure of which is incorporated herein by reference.
Number | Date | Country | |
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62750628 | Oct 2018 | US |