Microstructure control of conductive materials by powder surface coating

Abstract

An exemplary deposition method may include introducing hydrogen into a processing chamber with a powder disposed in a processing region. The method may include striking a first plasma including energetic hydrogen species into the processing region. The method may include exposing the powder to the energetic hydrogen species in the processing region. The method may include chemically reducing the powder by reaction of the powder with the energetic hydrogen species. The method may include removing process effluent including unreacted hydrogen from the processing region. The method may also include forming a material layer on particles of the powder in the processing region.

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS]

[0001] This application claims the benefit of and priority to non-provisional U.S. Ser. No. 17 / 184,802, filed February 25, 2021, entitled "MICROSTRUCTURE CONTROL OF CONDUCTING MATERIALS THROUGH SURFACE COATING OF POWDERS," the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002]

[0002] The present technology relates to coating processes and semiconductor chamber components. More specifically, the present technology relates to improved components and component materials. [Background technology]

[0003]

[0003] Integrated circuits are made possible by processes that produce intricately patterned layers of materials on substrate surfaces. To produce patterned materials on substrates, controlled methods for the formation and removal of exposed materials are required. Deposition and removal operations may include generating a local plasma in a processing region of a semiconductor processing chamber, for example, between a showerhead or gas distributor and a substrate support. Components of a semiconductor processing chamber may be or include a sintered composite material and electrical components incorporated for various functions, such as connection to a reference ground, providing an electrostatic chuck voltage, or facilitating localized substrate heating. On the other hand, a sintered composite material may be or include a refractory ceramic and one or more additives to impart improved electrical conductivity to the chamber components. When a sintered material is formed by sintering a blend of two or more powders, the non-uniform electrical conductivity of the sintered material may cause electric fields to concentrate in areas of relatively high additive concentration. In such cases, the creation of non-uniform electric fields can adversely affect the performance of the plasma system, for example, by compromising the electrostatic chuck, and can potentially damage the semiconductor being processed.

[0004]

[0004] Thus, there is a need for improved systems and system components that can be used to manufacture high quality devices and structures. These and other needs are addressed by the present technology. Summary of the Invention

[0005]

[0005] An exemplary deposition method may include introducing hydrogen into a processing chamber having a powder disposed within a processing region. The method may include striking a first plasma comprising energetic hydrogen species into the processing region. The method may include exposing the powder to the energetic hydrogen species in the processing region. The method may include chemically reducing the powder by reaction of the powder with the energetic hydrogen species. The method may include removing process effluent comprising unreacted hydrogen from the processing region. The method may also include forming a layer of material on particles of the powder in the processing region.

[0006] In some embodiments, forming the material layer may include exposing the powder to a plasma effluent of a first precursor. Forming the material layer may include evacuating the processing region. Forming the material layer may also include exposing the powder to a plasma effluent of a second precursor. The material layer may be or may include a reaction product of a plasma effluent of a first precursor and a plasma effluent of a second precursor. The first precursor may be or may include a metal, and the second precursor may be or may include oxygen. The powder may be or may include aluminum nitride. The powder may be or may include a passivation layer, and the passivation layer is removed by chemically reducing the powder. The material layer may be or may include yttrium oxide, cerium oxide, titanium oxide, calcium oxide, or magnesium oxide. The method may further include forming a surface oxide layer on the particles of the powder before forming the material layer. The layer of material may be a first layer of material and the method may further include forming a second layer of material overlying the first layer of material, The second layer may be or may include a different material than the first layer.

[0007]

[0007] Some embodiments of the present technology may include a method of producing a sinter mix. An exemplary method may include producing a first coated powder characterized by a first core-shell structure. The method may include producing a second coated powder characterized by a second core-shell structure. The second coated powder may be different from the first coated powder. The method may also include blending a sinter mix including the first coated powder and the second coated powder.

[0008] In some embodiments, the first core-shell structure has a core that can be or include aluminum nitride and a shell that can be or include at least one shell that includes a rare earth oxide, and the second core-shell structure has a core that can be or include aluminum nitride and a shell that can be or include at least one shell that includes a transition metal oxide.

[0009] Some embodiments of the present technology may include a sintered material. An exemplary sintered material may be characterized by a microstructure. The microstructure may include a primary phase defining a plurality of grain boundaries. The microstructure may include a secondary phase confined to the plurality of grain boundaries. The secondary phase may comprise less than or about 3% by weight of the sintered material.

[0010] In some embodiments, the primary phase may be or may include aluminum nitride. The secondary phase may be or may include yttrium oxide. The sintered material may be formed by sintering the coated powder. The coated powder may be characterized by a core-shell structure including a core of aluminum nitride and at least one shell including a transition metal oxide or a rare earth oxide. The coated powder may be produced by a deposition process including introducing hydrogen into a processing chamber. The powder may be disposed in a processing region of the processing chamber. The deposition process may include striking a first plasma including energetic hydrogen species into the processing region. The deposition process may include exposing the powder to the energetic hydrogen species in the processing region. The deposition process may include chemically reducing the powder by reaction of the powder with the energetic hydrogen species. The deposition process may include removing process effluent including unreacted hydrogen from the processing region. The deposition process may also include forming a material layer on particles of the powder in the processing region. The sintered material may be configured to be incorporated into a plasma processing system as a substrate support.

[0011]

[0011] Such techniques may provide many advantages over conventional systems and techniques. For example, the methods and systems may provide coated powders, sinter blends, and sintered materials with improved compatibility with plasma processing applications. For example, the powder may be chemically reduced to remove a passivation layer on the powder particles. In this manner, a material layer may be coated directly onto the powder, for example, by atomic layer deposition. By sintering one or more coated powders, the sinter blend may enable the formation of a sintered material with desired tailored electrical properties. The sintered material may thus have improved electrical properties at high temperatures, including temperatures at which semiconductor processing operations are performed. These and other embodiments, along with their many advantages and features, are described in more detail in conjunction with the following description and accompanying drawings.

[0012] A further understanding of the nature and advantages of the disclosed technology may be realized by reference to the remaining parts of the specification and drawings. [Brief description of the drawings]

[0013] [Figure 1] 1 shows a schematic diagram of an exemplary processing chamber in accordance with some embodiments of the present technique. [Diagram 2] 1 illustrates exemplary operations in a deposition method according to some embodiments of the present technique. [Diagram 3] FIG. 1 shows a schematic diagram of a powder during a deposition method according to some embodiments of the present technique. [Figure 4] 1A-1D depict schematic diagrams of exemplary processing chamber components formed according to methods in accordance with some embodiments of the present technique;

[0014]

[0017] Some drawings are included as schematic diagrams. It should be understood that the drawings are for illustrative purposes and are not to be considered to scale unless specifically stated to be to scale. Furthermore, the drawings, as schematic diagrams, are provided to aid in understanding and may not include all aspects or information compared to realistic representations and may include elements that are exaggerated for illustrative purposes.

[0015]

[0018] In the accompanying drawings, similar components and / or features may have the same reference numbers. Furthermore, various components of the same type may be distinguished according to the reference numbers by a letter that distinguishes the similar components. If only a first reference number is used in this specification, the description is also applicable to any of the similar components having the same first reference number regardless of the letter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016]

[0019] As part of semiconductor processing techniques, deposition and removal operations may include generating a local plasma between a processing region of a semiconductor processing chamber, such as a showerhead or gas distributor, and a substrate support. The components of the semiconductor processing chamber may be or include a sintered composite material and may also include electrical components incorporated for various functions, such as connection to a reference ground, providing an electrostatic chuck voltage, or facilitating local substrate heating. The sintered composite, on the other hand, may be or include a refractory ceramic and one or more additives to impart improved electrical conductivity to the chamber components. When the sintered material is formed by sintering a mixture of two or more different powders, one refractory ceramic and one additive, particle segregation may occur in the composite material, which forms conductive particle inclusions in the microstructure of the sintered composite material. Under plasma operating conditions, such as the temperatures used in the deposition process, electronic conduction through the sintered composite material may occur preferentially through the particle inclusions. The preferential conductivity through the particles may concentrate the electric field in the regions of higher concentration of the additives. In such cases, preferential conductivity effects can adversely affect the performance of the plasma system or even damage the semiconductor substrate being processed. For example, non-uniformities in the electric field adjacent to the substrate holder can reduce the effectiveness of an electrostatic chuck system configured to hold the substrate on the substrate holder.

[0017]

[0020] Conventional techniques approach this limitation by controlling plasma operating conditions (e.g., operating pressure, plasma power, duty cycle, or pulse frequency), which can limit the operating window. The present technique overcomes these limitations by implementing improved deposition methods to remove the natural passivation layer from the powder particles, allowing deposition of material directly onto the powder particles, for example, by atomic layer deposition. Furthermore, sintering the coated powder can provide a uniform distribution of conductive additives throughout the sintered material, thereby reducing the formation of conductive particle inclusions. This allows the manufacture of coated powders to create a variety of improved sintered materials, including, but not limited to, plasma processing chamber components that exhibit improved electrical properties at temperatures used in semiconductor processing. As a result, the sintered materials can be implemented in electrostatic chuck applications, such as Coulomb and Johnsen-Rahbek chucks.

[0018]

[0021] After describing general aspects of a chamber capable of performing plasma processing according to embodiments of the present technology, specific methodologies and component configurations may be discussed. It should be understood that the described technology can be used to improve numerous film formation processes, and therefore the technology is not intended to be limited to the specific films and processes discussed, but rather is applicable to a variety of processing chambers and operations.

[0019]

[0022] FIG. 1 shows a schematic diagram of an exemplary processing chamber 100 according to some embodiments of the present technology. The drawing may show an overview of a system incorporating one or more aspects of the present technology and / or may perform one or more operations according to embodiments of the present technology. Further details of the chamber 100 or the method performed may be further described below. Although the chamber 100 may be utilized to form coated powders according to some embodiments of the present technology, it should be understood that the method may be similarly performed in any chamber in which film formation may occur. For example, while the chamber 100 is illustrated in a horizontal rotating configuration, alternative embodiments may include a fluidized bed configuration, or a plasma powder synthesis system. The processing chamber 100 may include a chamber body 102, a plasma system 104 within the chamber body 102, a temperature control system 106, and a remote plasma system 108 coupled to the chamber body 102 and configured to provide plasma effluent to a processing region 120 of the chamber body 102.

[0020]

[0023] The powder can be provided to the processing region 120 through a material feedthrough (e.g., a port or conduit), which can be sealed for processing using a slit valve, gate valve, or door. The powder can be mechanically mixed during processing. To this end, the processing region 120 or the chamber body 102 can be rotatable about an axis 147, as indicated by arrow 145, for example by an electromechanical rotating element 149 configured to rotate one or more structures inside the chamber body 102, for example by rotating the chamber body 102 about the axis 147. Alternatively, the powder can be mixed and suspended in the processing region 120 by convective action of a gas introduced during the deposition process, for example by controllable fluidization to limit entrainment and powder loss.

[0021]

[0024] Precursors may be provided to the chamber 100 by a gas delivery system 110, as described below. Although one inlet for the gas delivery system 110 is shown in FIG. 1, the chamber 100 may include multiple gas inlets coupled to the chamber body 102 at one or more locations. For example, plasma precursors may be introduced to the chamber body by a remote plasma system 108, while a second gas inlet may provide gases that would adversely affect the deposition process due to plasma dissociation. Gases may be removed from the chamber body 102 by a gas removal system 112. The gas removal system may include a vacuum system configured to facilitate reduced pressure operation during the deposition process and to evacuate the chamber to remove process effluents and unreacted process gases. A measurement and control system may be coupled to the chamber to measure the operating pressure at one or more locations (e.g., the gas delivery system 110, the gas removal system 112, or the processing region 120). In another example, the temperature control system 106 can include temperature sensors and heating elements configured to supply heat to or remove heat from the processing region 120. In this manner, the chamber 100 can perform controlled deposition and removal processes, such as plasma etching and removal, and atomic layer deposition.

[0022]

[0025] As part of plasma processing of the powder in the chamber 100, according to the methods described below, the plasma system 104 may be configured to form a plasma in the processing region 120. The plasma system 104 may be or may include an indirect plasma system (e.g., RF capacitively coupled plasma) configured to form a plasma in the processing region 120 by generating a sufficiently strong electric field inside the chamber body 102. In some embodiments, the plasma system 104 may be or may include a direct plasma system such that one or more electrode surfaces are disposed within the chamber body. In this manner, the processing region 120 may be defined between a live electrode of the plasma system 104 and a reference ground electrode. The plasma system 104 may also include a control system and a power system, such as an impedance matching circuit and a 13.56 MHz RF power source.

[0023]

[0026] Similarly, the remote plasma system 108 may be or include a direct or indirect plasma system (e.g., an inductively coupled RF plasma system or a capacitively coupled RF plasma system) that may be configured to decompose the precursor into a plasma effluent that can be provided to the processing region 120. For example, the gas delivery system 110 may include a quartz inlet tube coupled with a feedthrough to the chamber body 102. In such an arrangement, the remote plasma system 108 may be or include an ICP or CCP system disposed outside the quartz inlet tube and configured to form a plasma in the quartz inlet tube. As described with reference to FIG. 2, the precursor may include an inert carrier gas and a reactive precursor, which may be a vapor or gas or may include a vapor or gas. In this manner, the remote plasma system 108 may form an indirect plasma in the precursor and decompose the precursor. The decomposed precursor may be or include a plasma effluent, which may be or include a carrier gas, an unreacted precursor, and a plasma-generated species. The plasma-generated species can serve as reactants in chemical reaction-mediated deposition processes such as atomic layer deposition. Similar to the plasma system 104, the remote plasma system 108 can also include a control system and a power system (e.g., an impedance matching circuit and a 13.56 MHz RF power source).

[0024]

[0027] The temperature control system 106 may be configured to maintain an internal temperature within the processing region according to the processing recipe. For example, as part of atomic layer deposition, a deposition substrate (e.g., a powder) may be heated to a reaction temperature favorable for a particular reaction product. In the illustrated example, the surface reactions forming a material layer on the deposition substrate may be thermodynamically favored at high temperatures. In this manner, the temperature control system 106 may provide heat to the processing region. In some embodiments, the temperature control system may be at least partially integrated into the plasma system 104. For example, electrodes of the plasma system 104 may incorporate heating and / or cooling elements, allowing the plasma system to operate within a range of operating temperatures.

[0025]

[0028] In some embodiments, the chamber 100 can be configured to produce powders in which the particles of the powder are coated with one or more layers of material. As described below with reference to the methods and systems, the chamber 100 enables the production of improved coated ceramic powders, which can be incorporated into sintering blends and sintered materials. Such sintered materials can exhibit improved electrical properties at the high temperatures characteristic of plasma deposition and removal operations as part of semiconductor processing.

[0026]

[0029] 2 illustrates exemplary operations in a deposition method 200 according to some embodiments of the present technique. The method may be performed in a variety of processing chambers, including the processing chamber 100 described above. The method 200 may include a number of optional operations that may or may not be specifically related to some embodiments of the method according to the present technique. For example, many of the operations are described to provide a broader scope of structure formation, but are not essential to the technique or may be performed by alternative methodologies that will be readily understood.

[0027]

[0030] Method 200 may include additional operations prior to the commencement of the recited operations. For example, the additional processing operations may include producing a powder, for example by ball milling a material feedstock to produce a powder of a characteristic size. Method 200 may optionally include delivering the powder to a processing region of a processing chamber (e.g., processing chamber 100 described above) or to a processing region of another chamber that may include components as described above. Method 200 describes the operations shown generally in FIG. 3, the illustrations of which will be described in conjunction with the operations of method 200. FIG. 4 illustrates an exemplary semiconductor processing system incorporating materials produced according to some embodiments of method 200. It should be understood that only partial schematics are shown in FIGS. 3-4, and the processing system may include subsystems as illustrated in the drawings, as well as alternative subsystems of any size or configuration that may still benefit from aspects of the present technology.

[0028]

[0031] FIG. 3 shows a schematic diagram of a powder 300 during an operation of a deposition method 200 according to some embodiments of the present technique. In some embodiments, the method 200 may include one or more operations preceding those illustrated in FIG. 2. For example, one or more processes may be performed to form the powder 300 from a feedstock material. For example, the powder 300 may be formed by chemically converting an oxide to a nitride and may be cleaned, for example, by calcination, etching, or degreasing. Examples of nitride synthesis may include, but are not limited to, carbothermal nitridation and / or direct nitridation. Furthermore, the powder 300 may be introduced into a processing chamber (e.g., chamber 100) carrying a passivation layer 305. For example, the powder 300 may be or include aluminum nitride, which may develop an oxide passivation layer upon exposure to oxygen during cleaning or upon exposure to air under ambient conditions.

[0029]

[0032] As illustrated in FIG. 3A, in operation 205, the method 200 may include introducing hydrogen into the processing region of the chamber. As an approach to chemically reduce the passivation layer 305, hydrogen may form a hydrogen plasma, a hydrogen-rich plasma, or a trace hydrogen plasma in the processing region. For example, operation 205 may precede the hydrogen reduction of the passivation layer as an approach to provide improved control of the surface material properties of the powder 300. The flow rate of hydrogen introduced into the chamber may depend, at least in part, on one or more parameters of the chamber, the powder 300, or the method 200. For example, the flow rate here may be such that the plasma may form sufficient energy density or species density, e.g., ions, free electrons, or active hydrogen, to promote hydrogen reduction of the passivation layer 305. In contrast, the flow rate of hydrogen may be limited by entrainment of the powder 300 in the flow, which may occur if the flow rate is too high. In such cases, the hydrogen may entrain the powder 300 and carry it out of the processing region, which should be avoided.

[0030]

[0033] In some embodiments, the precursor 307 is greater than or about 0.1 SLM, greater than or about 0.2 SLM, greater than or about 0.2 SLM, greater than or about 0.3 SLM, greater than or about 0.3 SLM, greater than or about 0.4 SLM, greater than or about 0.4 SLM, greater than or about 0.5 SLM, greater than or about 1 SLM, greater than or about 1.5 SLM, greater than or about 2 SLM, greater than or about 2.5 SLM, greater than or about 3 SLM, greater than or about 3.5 SLM, greater than or about 4 SLM, greater than or about 4.5 SLM. or about 4.5 SLM, greater than or about 5 SLM, greater than or about 5.5 SLM, greater than or about 6 SLM, greater than or about 6.5 SLM, greater than or about 7 SLM, greater than or about 7.5 SLM, greater than or about 8 SLM, greater than or about 8.5 SLM, greater than or about 9 SLM, greater than or about 9.5 SLM, greater than or about 10 SLM, or more.

[0031]

[0034] In some embodiments, hydrogen may comprise an inert carrier gas. In plasma systems, the inert carrier gas (also called "forming gas") facilitates plasma ignition and control of plasma conditions. For example, providing hydrogen with a given inert gas fraction allows the plasma to operate under controlled plasma conditions, such as ionization fraction, ion temperature, or electron temperature. Thus, precursor 307 may be or may include helium or argon and may be greater than or about 0.1 SLM, greater than or about 0.2 SLM, greater than or about 0.2 SLM, greater than or about 0.3 SLM, greater than or about 0.3 SLM, greater than or about 0.4 SLM, greater than or about 0.4 SLM, greater than or about 0.5 SLM, greater than or about 1 SLM, greater than or about 1.5 SLM, greater than or about 1.5 SLM, greater than or about 2 SLM, greater than or about 2.5 SLM, greater than or about 3 SLM, greater than or about 3.5 SLM, greater than or about 4 SLM, greater than or about 4.5 SLM, greater than or about 5 SLM, greater than or about 5.5 SLM, greater than or about 6 SLM, greater than or about 6.5 SLM or or about 6.5 SLM, greater than or about 7 SLM, greater than or about 7 SLM, greater than or about 7.5 SLM, greater than or about 8 SLM, greater than or about 8.5 SLM, greater than or about 9 SLM, greater than or about 9.5 SLM, greater than or about 10 SLM, greater than or about 10.5 SLM, greater than or about 11 SLM, greater than or about 11.5 SLM, greater than or about 12 SLM, greater than or about 12.5 SLM, greater than or about 13 SLM, greater than or about 13.5 SLM, greater than or about 14 SLM, greater than or about 14.5 SLM, greater than or about 15 SLM, or greater than or about 15 SLM.

[0032]

[0035] Following the introduction of hydrogen to the processing region, the method 200 may include striking a plasma in the processing region in operation 210. The plasma may be or may include a hydrogen plasma, and thus may include energetic plasma species, such as hydrogen ions, hydrogen radicals, or metastable diatomic hydrogen. The hydrogen plasma may be formed in the processing region while the powder 300 is suspended in the processing region or while passing through the processing region. The plasma processing may be based on hydrogen supplied with a carrier gas, such as argon or helium, to generate the plasma, and hydrogen may constitute a proportion of the material in the gas mixture. For example, in some embodiments, a plasma may be generated from a gas mixture containing greater than or about 0.5%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, greater than or about 1.0%, or more than 1.0% hydrogen, although in some embodiments the hydrogen concentration may be kept less than or about 20%, or less than or about 10% to limit the amount of reducing agent generated. The pressure in the processing chamber during processing may be maintained at or below 10 Torr, and may be maintained at or below 8 Torr, 6 Torr, 5 Torr, 4 Torr, 3 Torr, 2.5 Torr, 2.0 Torr, 1.5 Torr, 1.0 Torr, 0.5 Torr, or less. In some embodiments, the chamber may be pre-coated prior to plasma processing, which may minimize the chance of material contamination due to hydrogen etching or reduction.

[0033]

[0036] As described with reference to FIG. 1, suspending the powder 300 may include rotating a chamber body of a deposition system, such as the chamber body 102 of FIG. 1, and repeatedly passing the powder 300 through a processing region and a hydrogen plasma. In some cases, the powder 300 may be suspended by a controlled gas flow to form a fluidized bed. Thus, following striking the plasma, the method 200 may include exposing the powder 300 to a hydrogen plasma in operation 215. By exposing the powder 300 to the hydrogen plasma, the passivation layer 305 may react with energetic plasma species present in the hydrogen plasma. Thus, in parallel with exposing the powder 300 to the plasma, the method 200 may include chemically reducing the powder 300 and / or the passivation layer 305 in operation 220. The passivation layer 305 may be or may include a metal oxide and may react with the hydrogen plasma to produce metal and water vapor. In this manner, the reduction reaction can preferentially remove the passivation layer 305, so that the powder 300 can serve as a substrate for the deposition of a subsequent layer of material. For example, the powder 300 can be or include aluminum nitride, and the passivation layer 305 can be or include aluminum oxide. In this example, chemically reducing the powder can include reacting the aluminum oxide with energetic hydrogen species to form water vapor and aluminum, which can remain on the surface of the powder 300 after subsequent removal of the passivation layer 305. To this end, the hydrogen plasma can also include nitrogen, which exposes the aluminum to energetic nitrogen species and allows the conversion of the residual aluminum on the surface of the powder 300 to aluminum nitride.

[0034]

[0037] Following chemically reducing the powder 300, the method 200 may include removing process effluents from the processing region in operation 225. The process effluents may be or may include unreacted hydrogen or water vapor, among other plasma reaction products. Because water vapor and hydrogen may inhibit the formation of a material layer by atomic layer deposition, residual gas remaining after plasma removal of the passivation layer 305 may be removed, for example, by the gas removal system 112 of FIG. 1. To limit losses of the powder 300, operations performed to pass the powder 300 through the processing region or to suspend the powder in the processing region may be stopped before operation 225. Removing the process effluents may also include introducing an inert purge gas into the processing chamber to exchange gases. In some embodiments, the powder may be heated, for example, by the temperature control system 106, while the chamber is maintained under vacuum to degas the powder.

[0035]

[0038] In some embodiments, the method 200 may optionally include oxidizing the powder 300 in operation 230. Operation 230 may thus include introducing oxygen into the processing region of the chamber. Introducing oxygen into the processing region as part of the plasma-based deposition allows for the formation of a controlled oxide layer on the powder 300. In contrast to the passivation layer 305, the controlled oxide layer may be formed under controlled conditions, for example in an oxygen plasma in the processing region, such that an oxide layer may be formed on the powder with a characteristic and uniform thickness. Additionally or alternatively, operation 230 may include thermal oxidation of the powder 300, followed by removal of the passivation film 305. The surface oxide layer may provide improved control of electronic properties in sintered materials formed with the powder 300, for example by acting as a diffusion barrier or by defining grain boundaries in the sintered material. In this manner, it may be advantageous to reduce the powder 300 to remove the passivation layer 305, and then oxidize the powder 300 under controlled conditions to modify the oxide layer.

[0036]

[0039] Following oxidizing the powder 300, the method 200 may include forming a material layer 315 on the powder 300 in operation 235. In some embodiments, forming the material layer 315 on the powder 300 may include performing an atomic layer deposition (ALD) process operation, which uniformly coats the particles of the powder 300. For example, operation 235 may include introducing a plasma effluent into the processing region. The plasma effluent may be or may include plasma-generated species formed by a remote plasma system (e.g., remote plasma system 108 of FIG. 1) in communication with the processing region. Introducing the plasma effluent may include introducing a carrier gas containing the plasma effluent. In this manner, by introducing the plasma effluent into the processing region, the powder 300 may be exposed to the plasma effluent of one or more precursors that have been subjected to plasma decomposition. The plasma effluent may thus be or may include ions, activated radicals, metastable species, and other decomposition products, and may be characterized by a lower average energy distribution than a direct plasma system. On the other hand, exposing the powder 300 to the plasma effluent may form a monolayer adsorbed by the plasma effluent on the surface of the particles of the powder 300 that serves as a precursor to the formation of the material layer 315. In a second operation of the atomic layer deposition, the operation 235 may include removing the plasma effluent by purging the processing region of gas while retaining the powder 300 bearing the adsorbed monolayer. Purging the processing region may be performed using a gas removal system, such as the gas removal system 112 of FIG. 1. Following the purging, the second precursor may be decomposed into a second plasma effluent, such that the powder 300 is exposed to the second plasma effluent. The second precursor may be selected to decompose into plasma to generate species that react with the adsorbed monolayer on the powder 300 to form the material layer 315. Following the formation of the material layer 315, the unreacted plasma effluent and reaction by-products may be removed by the gas removal system.

[0037]

[0040] In some embodiments, the first and second precursors may be selected such that the material layer 315 may be or may include a conductive additive to improve the electrical conductivity of the sintered material formed by sintering the powder 300. In this manner, one precursor may be or may include a metal and the other precursor may be or may include oxygen. The metal may be or may include a rare earth element or a transition metal. For example, the first precursor may be or may include yttrium, cerium, titanium, calcium, or magnesium, and the material layer 315 may be or may include an oxide, such as yttrium oxide, cerium oxide, titanium oxide, calcium oxide, or magnesium oxide.

[0038]

[0041] In some embodiments, the forming operation of operation 235 can be repeated to deposit multiple monolayers such that the material layer 315 can be formed monolayer by monolayer, and the thickness of the material layer 315 can be an integer multiple of the thickness of the monolayer and the number of repetitions of operation 235. Additionally, following operation 235, a second material layer 320 can be formed overlying the material layer 315 by repeating operation 235 with a different set of first and second precursors. For example, if the material layer 315 can be or include yttrium oxide, the second material layer 320 can be or include a different oxide, such as titanium oxide, magnesium oxide, or another transition metal oxide or rare earth oxide. Thus, the coated powder formed from the powder 300 by method 200 can include a controlled oxide layer, the material layer 315, and one or more additional layers of different materials, such as the second material layer 320.

[0039]

[0042] Thus, method 200 and its constituent operations may provide one or more improvements to plasma-based deposition processes for depositing layers of material on powders by ALD. For example, method 200 may provide coated powders characterized by a core-shell structure, where the core may be or include a ceramic material, such as aluminum nitride, and the shell or shells may be or include, for example, transition metal oxides or rare earth oxides. Due to the layer-by-layer deposition of atomic layer deposition, the shells may be precisely deposited such that the relative composition of the coated powder may be determined by repeating operation 235 a predetermined number of times. Furthermore, plasma removal of the natural passivation layer improves control of the surface chemistry, which in turn improves the electrical properties of sintered materials formed using the coated powders.

[0040]

[0043] As described below, coated powders can be produced to provide improved electrical properties to materials formed by sintering the coated powders. To this end, method 200 can be performed to produce and combine a plurality of coated powders into a sintered mix. For example, a first coated powder can be or include an aluminum nitride powder coated with a layer of yttrium oxide. A second coated powder can be or include an aluminum nitride powder coated with a layer of titanium oxide. In this case, a sintered mix can be produced by blending the first and second coated powders, such that a sintered material formed with the sintered mix can be characterized by improved electrical properties due in part to improved control of the relative composition of the coating materials and in part to improved distribution of the coating materials in the sintered mix. The distribution of the coating materials can be improved, particularly as compared to bulk powder blends that can suffer from agglomeration or density segregation, as examples of phenomena that can limit the effectiveness of the blend and adversely affect the material properties of the sintered material.

[0041]

[0044] FIG. 4 shows a schematic diagram of an exemplary plasma processing system including one or more components formed by a method according to some embodiments of the present technique. FIG. 4 further shows details regarding the semiconductor processing system 400 and one or more components that can be incorporated into the system 400 that can be or include a sintered material. Alternatively, the sintered material can be formed by sintering a coated powder, such as the coated powder produced by the method 200. The system 400 should be understood to include any feature or aspect of a semiconductor processing chamber and can be used to perform semiconductor processing operations including deposition, removal, and cleaning operations. The system 400 can show some of the chamber components discussed, which can be incorporated into a typical semiconductor processing system, can show a view through the center of the pedestal and gas distributor, or can otherwise be of any size. Any aspect of the system 400 can also be incorporated with other processing chambers or systems, as would be readily understood by one of ordinary skill in the art.

[0042]

[0045] The system 400 can include a semiconductor processing chamber 450 having a showerhead 405 through which precursors 407 can be delivered for processing and which can be configured to form a plasma 410 in a processing region between the showerhead 405 and a pedestal or substrate support 415. The showerhead 405 is shown at least partially inside the chamber 450 and can be understood to be electrically isolated from the chamber 450. In this manner, the showerhead 405 can act as a powered electrode or a reference ground electrode of the direct plasma system to expose a substrate held on the substrate support 415 to plasma-generated species. The substrate support 415 can extend through a base of the chamber 450. The substrate support 415 can include a support platen 420 that can hold a semiconductor substrate 430 during a deposition or removal process used to form a patterned structure on the semiconductor substrate 430.

[0043]

[0046] The support platen 420 may be or may include a sintered material formed from a coated powder manufactured according to an embodiment of the method 200. The support platen 420 may incorporate embedded electrodes to provide an electrostatic field used to hold the semiconductor substrate and may also include a thermal control system that may facilitate processing operations, including but not limited to deposition, etching, annealing, or desorption. In some embodiments, the support platen 420 may incorporate a plate, a perforated plate, a mesh, a wire screen, or any other distribution arrangement of conductive elements. The embedded electrode may be or may include a tuning electrode to provide further control over the plasma 410, for example, by adjusting the electric field near the surface of the support platen. Similarly, a bias electrode and / or an electrostatic chuck electrode may be coupled to the support platen 420. The bias electrode may be coupled to a power source, such as DC power, pulsed DC power, RF bias power, pulsed RF power or bias power, or a combination of these or other power sources. In this manner, the substrate support 415 and support platen 420 may be used not only to hold the semiconductor substrate 430 during plasma processing operations, but also to condition the plasma 410. Adjusting the conditions of the plasma may include performing automatic impedance matching to maintain plasma conditions during plasma processing operations, for example, while the composition of the plasma 410 is changing, or as the surface of the semiconductor substrate 430 changes, for example due to deposition of a dielectric film on the electrode surface. Thus, precise control of the plasma 410 may depend on the material properties of the substrate support 415 and support platen 420.

[0044]

[0047] For example, a potential difference may be established between the plasma 410 and the showerhead 405. A potential difference may also be established between the plasma 410 and the support platen 420. In this case, a power source in communication with each conductive surface may be used to adjust the flow characteristics of the ground path, for example, by employing an impedance matching ballast circuit. The impedance matching circuit may be or include a variable capacitor. The matching circuit may thus adjust the variable capacitor to maximize deposition rate and minimize thickness non-uniformity independently during the semiconductor deposition process, such as when the system 400 includes independent control circuits for the showerhead 405 and the support platen 420. However, the effectiveness of the control circuit to maintain the plasma 410 near the set point may be hampered by the thermal dependence of electrical conductivity of the chamber 450 components and the electric field dynamics caused by non-uniform conduction within the chamber components.

[0045]

[0048] In some cases, the support platen 420 or other chamber components may be formed from a sintered material. For example, a powder may be pressed into a mold and heated until the powder particles fuse to the sintered material. Subsequent operations, such as annealing, machining, incorporating electrical components, and applying protective surface coatings, may be performed to complete the component, thereby providing a working component that can be incorporated into a plasma system. Advantages of using sintered materials may include that the completed component may function as a refractory conductor with favorable thermal deformation characteristics and chemical resistance to plasma etching, as well as electrical conductivity. One disadvantage, however, is that the electrical conductivity of sintered components may increase with temperature. Furthermore, electrical conductivity may increase non-uniformly with temperature resulting from the properties of the microstructure of the sintered material.

[0046]

[0049] At temperatures below the transition temperature, the electrical conductivity of the sintered material is dominated by a grain boundary conduction mechanism, below which electronic current is confined to the grain boundaries between the grains of the microstructure. However, above the transition temperature, conductive particle inclusions in the microstructure of the sintered material can cause conduction to shift to a grain conduction mechanism where electronic current flows through the conductive particle inclusions rather than through the grain boundaries, causing a decrease in the resistivity of the sintered material and a decrease in surface charge. If the conductive particle inclusions are unevenly distributed in the sintered material, conduction can occur preferentially in areas of higher inclusion density, which can cause electric field density to concentrate at locations on the support platen 420, which can reduce the effectiveness of the electrostatic chuck contained within the support platen 420. In some embodiments, the transition can occur at temperatures in the range of 400-600° C., at which point the chucking voltage can increase with temperature to a point where the electrostatic chuck system is no longer able to provide the charge to maintain the chucking force and hold the substrate to the surface.

[0047]

[0050] Advantageously, sintered materials formed from coated powders produced by the operations of method 200 may exhibit improved electrical properties at temperatures employed in plasma processing operations, as described with reference to FIG. 2. For example, where a conventional sintered material may be formed from a blend of powders including ceramics and conductive additives (e.g., metal oxides or rare earth oxides), the distribution of the conductive additives may depend on the blending efficiency, and sintering of the additive powder particles may result in segregation of oxide particles in the microstructure of the sintered material. In this manner, the resulting sintered material may include conductive particle inclusions that impair the electrical properties of the material at process temperatures. For example, in a sintering mix including aluminum nitride powder and yttrium oxide powder, sintering may result in the formation of yttrium aluminum oxide particle inclusions in the microstructure of the sintered material. Yttrium aluminum oxide may exhibit temperature-dependent electrical conductivity that may induce a transition to a particle conduction mechanism above the transition temperature of the sintered material.

[0048]

[0051] In contrast, sintering the coated powder with one or more shells formed by the operations of method 200 (as described with reference to FIG. 3 ) can result in an improved microstructure 460. By forming a sintered material using the coated powder, the core-shell structure can function to control the distribution of the conductive additive. On the other hand, the controlled distribution can limit the movement of the conductive additive during sintering, resulting in two main phases in the microstructure 460. The microstructure 460 can include a primary phase 470 and a secondary phase 480, but can be substantially free of conductive particle inclusions. For example, the primary phase 470 can define a three-dimensional network of grain boundaries, and the secondary phase 480 can be confined to the grain boundaries. The primary phase 470 can be or can include a ceramic material (such as that of powder 300 in FIG. 3 ). The secondary phase 480 can be or can include a layer of material formed in operation 235 of FIG. 2 that has reacted with the material of the powder core to form an alloy oxide. For example, if the core of the coated powder is aluminum nitride and the shell includes yttrium oxide, the secondary phase 480 may be or may include yttrium aluminum oxide.

[0049]

[0052] Advantageously, if the microstructures 460 confine the secondary phase 480 to the grain boundaries between grains of the primary phase 470, the sintered material may be prevented from transitioning to a particle conduction mechanism at process temperatures. In this manner, maintaining the grain boundary conduction mechanism may improve the electrical performance of components formed from the sintered material without significantly degrading other material properties, such as resistance to etching and oxidation, limited thermal deformation, or refractory properties. As a result, the control and uniformity of the electric field emanating from the support platen 420 may be improved during semiconductor processing operations, thereby reducing the impact on electrostatic chucking forces caused by particle conduction.

[0050]

[0053] Advantageously, by forming a sintered material from a coated powder, the composition of the sintered material can be precisely controlled. In a material formed by sintering a blend of two powders, the composition may depend on precise measurement and handling of the blend prior to sintering. In contrast, a coated powder can be formed to have a precise composition, due in part to the precise nature of the ALD technique, which forms a monolayer of coating material for each deposition cycle. In this way, each particle of the coated powder can include a precise amount of conductive additive on the surface, providing a sintered material with a controlled composition that can be selected to impart improved electrical properties to the sintered material.

[0051]

[0054] The microstructure 460 may be characterized by an average grain size, which may affect the electrical properties of the sintered material, where the grain size may correspond to the relative fraction of the primary phase 470 or the size of the powder particles used to form the sintered material. For example, a relatively high concentration of the primary phase 470 (where the primary phase 470 is characterized by a low electrical conductivity) may limit the effect of the secondary phase 480 on the electrical conductivity of the sintered material. Additionally, a relatively high concentration of the secondary phase may enable phase migration and the formation of conductive inclusions during sintering.

[0052]

[0055] In some embodiments, the coated particles can be formed with a shell that includes the conductive aid such that the sintered material contains less than or about 15% by weight, less than or about 14% by weight, less than or about 13% by weight, less than or about 12% by weight, less than or about 10% by weight, less than or about 9% by weight, less than or about 8% by weight, less than or about 7% by weight, less than or about 6% by weight, less than or about 5% by weight, less than or about 4% by weight, less than or about 3% by weight, less than or about 2% by weight, less than or about 1% by weight, less than or about 0.5% by weight, or less than or about 0.5% by weight.

[0053]

[0056] In the foregoing specification, for purposes of explanation, numerous details are set forth in order to provide an understanding of various embodiments of the present technology. However, it will be apparent to one skilled in the art that certain embodiments may be practiced without some of these details or with additional details.

[0054]

[0057] Although several embodiments have been disclosed, it will be recognized by those skilled in the art that various modifications, alternative configurations, and equivalents can be used without departing from the spirit of the embodiments. Moreover, many well-known processes and elements have not been described to avoid unnecessarily obscuring the present technology. Thus, the above description should not be considered as limiting the scope of the technology. Furthermore, while a method or process may be described sequentially or as steps, it should be understood that the operations may be performed simultaneously or in an order different from that listed.

[0055]

[0058] Where a range of values ​​is provided, unless the context clearly dictates otherwise, it is understood that each intervening value between the upper and lower limits of that range is also specifically disclosed, to the smallest fraction of the unit of the lower limit. Any intervening value stated or unstated in a stated range and any other stated or intervening value in the stated range are encompassed. The upper and lower limits of these smaller ranges may be independently included or excluded in the range, and each range in which either, neither, or both limits are included in the smaller range is also encompassed within the technology, subject to the specifically excluded limits in the stated range. Where one or both limits are included in a stated range, ranges excluding either or both of the included limits are also included.

[0056]

[0059] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to "a precursor" includes a plurality of such precursors, reference to "the layer" includes reference to one or more layers and equivalents thereof known to those skilled in the art, and so forth.

[0057]

[0060] Additionally, the words "comprise," "comprising," "contain," "containing," and "including," when used in this specification and the claims that follow, are intended to specify the presence of stated features, integers, components, or operations, but do not exclude the presence or addition of one or more other features, integers, components, operations, or groups.

Claims

1. 1. A deposition method comprising the steps of: introducing hydrogen into a processing chamber having a powder disposed within a processing region; striking a first plasma comprising energetic hydrogen species into the processing region; exposing the powder to the energetic hydrogen species in the treatment region; chemically reducing said powder by reaction of said powder with said energetic hydrogen species; removing a process effluent containing unreacted hydrogen from said treatment zone; and forming a layer of material on particles of the powder in the treatment region; Including, forming the layer of material exposing the powder to a plasma effluent of a first precursor; evacuating the processing region; and exposing the powder to a plasma effluent of a second precursor; wherein the layer of material comprises a reaction product of a plasma effluent of the first precursor and a plasma effluent of the second precursor.

2. The deposition method of claim 1 , wherein the first precursor comprises a metal and the second precursor comprises oxygen.

3. The deposition method of claim 1 , wherein the powder comprises aluminum nitride.

4. The deposition method of claim 1 , wherein the powder includes a passivation layer, and the passivation layer is removed by chemically reducing the powder.

5. The deposition method of claim 1 , wherein the material layer comprises yttrium oxide, cerium oxide, titanium oxide, calcium oxide, or magnesium oxide.

6. The deposition method of claim 1 further comprising forming a surface oxide layer on particles of the powder prior to forming the material layer.

7. the layer of material is a first layer of material; forming a second layer of material overlying the first layer of material, the second layer of material comprising a material different from the first layer of material; The deposition method of claim 1 further comprising:

8. 1. A method for producing a sinter mix, comprising the steps of: Producing a first coated powder characterized by a first core-shell structure; Producing a second coated powder different from the first coated powder, characterized by a second core-shell structure; and blending a sintering mix comprising the first coated powder and the second coated powder; Including, Producing the first coated powder or the second coated powder comprises: introducing hydrogen into a processing chamber having a powder disposed within a processing region; striking a first plasma comprising energetic hydrogen species into the processing region; exposing the powder to the energetic hydrogen species in the treatment region; chemically reducing said powder by reaction of said powder with said energetic hydrogen species; removing a process effluent containing unreacted hydrogen from said treatment zone; and forming a layer of material on particles of the powder in the treatment region; Including, forming the layer of material exposing the powder to a plasma effluent of a first precursor; evacuating the processing region; and exposing the powder to a plasma effluent of a second precursor; wherein the material layer comprises a reaction product of a plasma effluent of the first precursor and a plasma effluent of the second precursor.

9. The method of claim 8, wherein the first core-shell structure comprises an aluminum nitride core and at least one shell containing a rare earth oxide or a transition metal oxide.

10. 1. A method for producing a sintered material, comprising the steps of: The sintered material is a primary phase defining a plurality of grain boundaries; and a secondary phase confined to the grain boundaries of the sintered material, the secondary phase comprising less than or about 3% by weight of the sintered material; The present invention is characterized by a microstructure including The method is sintering the coated powder to form a sintered material; A method of manufacturing, wherein the coated powder is produced by the deposition method of claim 1.

11. The method of claim 10 , wherein the primary phase comprises aluminum nitride.

12. The method of claim 11 , wherein the secondary phase comprises yttrium oxide.

13. The method of claim 10, wherein the coated powder is characterized by a core-shell structure comprising a core of aluminum nitride and at least one shell containing a transition metal oxide or a rare earth oxide.

14. The method of claim 10 , configured to be incorporated into a semiconductor processing system as a substrate support.

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