High-temperature aluminum nitride heater with multi-zone capability

Abstract

To provide an electric heater apparatus for fabrication of semiconductor wafers.SOLUTION: Embodiments of an electric heater apparatus are disclosed. In one embodiment, an electric heater apparatus includes: (a) a first thermally conductive layer comprising an electrically insulating material; (b) one or more electrically conductive heating elements disposed in one or more grooves arranged on the top side of the first thermally conductive layer; and (c) a second thermally conductive layer disposed on the top side of the first thermally conductive layer over the one or more heating elements. The one or more heating elements include one or more refractory hard metals doped with at least one of carbon, nitrogen, aluminum, yttrium, or oxygen. The doped one or more refractory hard metals include a temperature-insensitive electrical resistance over operational temperatures ranging from ambient temperature to about 850°C as compared to undoped refractory hard metals. The one or more heating elements are independently controllable to provide one or more heating zones.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] 〔Related Applications〕 This application claims the benefit of U.S. Provisional Patent Application No. 62 / 843,241, filed May 3, 2019, which is hereby incorporated by reference in its entirety.

[0002] The present disclosure relates to an electric heater, and more particularly, to a heater used in the fabrication of semiconductor wafers such as silicon wafers and gallium arsenide wafers.

Background Art

[0003] Electric heaters used in semiconductor wafer manufacturing can be used at various stages of wafer manufacturing / processing, including material deposition (e.g., physical or chemical vapor deposition), material removal (e.g., etching or planarization), patterning (e.g., lithography), and modification of electrical properties (e.g., doping or annealing). Such electric heaters must be able to withstand highly erosive environments, be resistant to thermal shock under rapid temperature changes, and withstand extremely high temperatures over long periods. However, prior to the present disclosure, known electric heaters for semiconductor wafer manufacturing have had the following problems: (1) relatively large variations in electrical resistivity at high temperatures, which require complex and costly temperature control; (2) inability to easily perform multi-zone heating; (3) susceptibility to cracks or failures due to thermal stress and thermal cycling, and thus having components lacking in durability or long life; and (4) having components that cannot be co-fired simultaneously due to different coefficients of thermal expansion, resulting in additional manufacturing steps for assembly.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Accordingly, there is a need for an apparatus that solves these and other problems.

Means for Solving the Problems

[0005] In one embodiment of the present disclosure, an electric heater device includes one or more thermal conduction layers and one or more heating elements embedded within or between the one or more thermal conduction layers, and the one or more heating elements include molybdenum (Mo), tungsten (W), or any other refractory hard metal doped with at least one or more of carbon (C), nitrogen (N), aluminum (Al), or oxygen (O). In one embodiment, the heating element of the electric heater device includes molybdenum and molybdenum carbide (Mo2C) such that the carbide content exceeds 5%.

[0006] Among several advantages, the heating element of the electric heater device according to the present disclosure exhibits improved electrical resistivity stability at high temperatures, particularly in the range of about 300 °C to about 850 °C, and also in the range from about ambient temperature to about 850 °C.

[0007] In another embodiment, an electric heater device used when processing a semiconductor wafer in a wafer processing chamber, comprising: (a) a first thermal conduction layer including an electrically insulating material, an upper surface, and a bottom surface; (b) one or more conductive heating elements disposed in respective grooves of one or more grooves disposed on the upper surface of the first thermal conduction layer; and (c) a second thermal conduction layer disposed on the upper surface of the first thermal conduction layer covering the one or more heating elements, wherein the one or more heating elements include one or more refractory hard metals doped with at least one of carbon, nitrogen, aluminum, yttrium, or oxygen, and the one or more doped refractory hard metals have an electrical resistance less affected by temperature compared to the undoped refractory hard metal over an operating temperature from ambient temperature to about 850 °C, and the one or more heating elements are independently controllable to provide one or more heating zones along the upper surface of the first thermal conduction layer. An electric heater device is disclosed.

[0008] The first heat conduction layer can include a disk. The first heat conduction layer can be sintered, and one or more heating elements can initially include a high concentration among powders, paints, or pre-cut patterns from polymer sheets before sintering the first heat conduction layer. The concentration of carbon can vary from about 0.1 at% to about 50 at%, the concentration of aluminum can vary from about 0.1 at% to about 20 at%, the concentration of nitrogen can vary from about 0 at% to about 20 at%, the concentration of oxygen can vary from about 0 at% to about 5 at%, and the concentration of yttrium can vary from about 0 at% to about 3 at%. The first heat conduction layer includes aluminum nitride.

[0009] The electric heater device can include a third heat conduction layer disposed on the bottom surface of the first heat conduction layer. The third heat conduction layer can include a hub. The second and third heat conduction layers can include aluminum nitride. The electric heater device can include a sintered riser attached to the hub. Alternatively, the sintered riser can be joined to the hub, and the joined riser can form a helium-tight seal with the hub. The electric heater device can include one or more electrical interconnects disposed within each of one or more channels disposed on the bottom surface of the first heat conduction layer. The interconnects can be configured to conduct electricity from the hub to one or more heating elements and from one or more heating elements to the hub within a circuit. The interconnects can be configured to transmit sensor data from one or more temperature sensors to the hub. One or more temperature sensors can be disposed within each of one or more channels disposed on the bottom surface of the first heat conduction layer and below the third heat conduction layer. The third heat conduction layer can be disposed to cover one or more temperature sensors.

[0010] One or more heating elements and the first heat conduction layer can have functionally similar coefficients of thermal expansion so as to avoid harmful cracks or fractures in the electric heater device.

[0011] In another embodiment, an electric heater device used when processing a semiconductor wafer in a wafer processing chamber, comprising: (a) a sintered disk made of a thermally conductive and electrically insulating material, having an upper surface and a bottom surface; (b) one or more conductive heating elements disposed in respective grooves of one or more grooves disposed on the upper surface of the disk; (c) a first thermal conduction layer disposed on the upper surface of the disk covering the one or more heating elements; (d) one or more interconnects disposed in respective channels of one or more channels disposed on the bottom surface of the disk; and (e) a second thermal conduction layer including a hub disposed on the bottom surface of the disk covering the one or more interconnects, wherein the one or more heating elements include one or more refractory hard metals doped with at least one of carbon, nitrogen, aluminum, yttrium, or oxygen, and the doped one or more refractory hard metals have an electrical resistance that is less affected by temperature compared to the undoped refractory hard metals over an operating temperature from ambient temperature to about 850 °C, the one or more heating elements are independently controllable to provide one or more heating zones along the upper surface of the disk, and the one or more conductive heating elements are protected from chemical attack.

[0012] The concentration of carbon can vary from about 0.1 at% to about 50 at%, the concentration of aluminum can vary from about 0.1 at% to about 20 at%, the concentration of nitrogen can vary from about 0 at% to about 20 at%, the concentration of oxygen can vary from about 0 at% to about 5 at%, and the concentration of yttrium can vary from about 0 at% to about 3 at%. The thermally conductive and electrically insulating material can be aluminum nitride. The first and second thermal conduction layers can include aluminum nitride.

[0013] The electric heater device can include a riser attached to the hub. The riser can be joined to the hub, and the joined riser can form a helium tight seal with the hub. The interconnect can include one or more electrical interconnects configured to conduct electricity from the hub to one or more heating elements and from the one or more heating elements to the hub within the circuit.

[0014] The electric heater device can include one or more temperature sensors disposed within one or more channels. The second thermal conduction layer can be disposed to cover the one or more temperature sensors. The one or more heating elements and the disk can have functionally similar coefficients of thermal expansion so as to avoid harmful cracks or fissures in the electric heater device. The one or more heating elements can be independently controlled to provide one or more heating zones along the upper surface of the disk.

[0015] In another embodiment, a method of manufacturing an electric heater device used when processing a semiconductor wafer in a wafer processing chamber, the method comprising: (a) preparing a disk comprising aluminum nitride containing a sintering aid containing about 3 to about 5 wt% yttria, the disk including a top surface and a bottom surface; (b) creating one or more grooves in the top surface of the disk; (c) depositing one or more conductive heating elements in each of the one or more grooves disposed in the top surface of the disk, the one or more heating elements including one or more refractory hard metals doped with at least one of carbon, nitrogen, aluminum, yttrium, or oxygen, the doped one or more refractory hard metals having an electrical resistance that is less affected by temperature compared to the undoped refractory hard metal over an operating temperature from ambient temperature to about 850°C, the one or more heating elements being independently controllable to provide one or more heating zones along the top surface of the disk; (d) depositing a first powder containing aluminum nitride on the top surface of the disk to cover the one or more heating elements; (e) pressing the disk in a mold at least once to densify the first powder; (f) creating one or more channels in the bottom surface of the disk; (g) depositing one or more conductive interconnects in the one or more channels in the bottom surface of the disk; (h) depositing a second powder containing aluminum nitride on the bottom surface of the disk to cover the one or more interconnects; (i) pressing the disk in a mold at least once to densify the second powder; (j) machining and grinding the pressed disk to include a hub, the machined and processed disk defining an aluminum nitride matrix having embedded heating elements and interconnects; (k) sintering the aluminum nitride matrix at a temperature in the range of about 1600°C to about 1850°C, the sintering step being performed in a nitrogen environment under controlled heating to burn any temporary binder in the aluminum nitride matrix, the amount of carbon being such that the liquid phases of alumina and yttria result in an Al2O3 / Y2O3 molar ratio in the sintered aluminum nitride matrix of 10:3 to 0.Maintained below the oxygen content of aluminum nitride not associated with yttria in the aluminum nitride matrix to achieve a composition of 1:1, a portion of the amount of carbon is incorporated into one or more doped refractory hard metals of one or two or more conductive heating elements, and by sintering, a densified aluminum nitride matrix containing one or two or more conductive heating elements densified within the sintered aluminum nitride matrix is formed, and further includes the step of joining a riser sintered to a hub.

[0016] These and other embodiments are described herein.

[0017] To better understand the features described in this disclosure, reference can be made to the embodiments shown in the drawings. The components in the drawings are not necessarily to scale, and related elements may be omitted to emphasize and clearly show the novel features described herein. Also, as is well known in the art, system components can be arranged in various ways. In the figures, unless otherwise specified, like parts can be indicated by like reference numerals throughout different figures.

Brief Description of the Drawings

[0018]

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DETAILED DESCRIPTION OF THE INVENTION

[0019] The features, methods, devices, and systems described herein can be embodied in various forms, but several exemplary and non-limiting embodiments are shown in the drawings and will be described below. However, not all of the illustrated components in the present disclosure are necessary, and some implementations may include additional, different, or fewer components compared to the components explicitly described in the present disclosure. The arrangement and type of components can be changed without departing from the spirit or scope of the claims shown herein. Accordingly, it should be understood that any feature of any of the embodiments described with reference to the figures herein can be combined with or substituted for the features described in connection with other embodiments of the present disclosure.

[0020] In the present disclosure, various aspects of at least one embodiment of an electric heater device for manufacturing a semiconductor wafer will be described. Various embodiments of the electric heater device provide numerous advantages. For example, the electric heater device of the present disclosure provides an electric resistance heater that has a relatively small resistance change (i.e., the electrical resistance is relatively insensitive to temperature changes) compared to its metallic equivalent over the same test temperature during operation in the range of about ambient temperature to about 850°C, particularly in the range of about 300°C to about 850°C. Other advantages include the following. a. The composition of the heating element and its porosity allow for shrinkage that is compatible with the shrinkage of aluminum nitride. Since there is no excessive mismatch in shrinkage, the resulting heating element, which includes one or more heating elements embedded in an aluminum nitride matrix, does not develop harmful internal cracks or fractures. b. The heating element composition has a coefficient of thermal expansion that is moderately close to that of aluminum nitride upon sintering with aluminum nitride, and thus no cracks that would adversely affect the performance of the heater occur. c. The embodiments described herein include a multi-layer heating element disk and a riser assembly having a strong joint that can prevent helium leakage. d. The embodiments described herein provide a scalable design that provides single or multiple heating zones, enabling the design of various multi-zone heater configurations having functional temperature uniformity in the range of about ambient temperature to about 850°C. e. The embodiments described herein enable additional or multiple thermocouple temperature sensors that exceed those of known devices, and all of these sensors can withstand the heater fabrication process, which includes steps involving compression of components, embedding of components, and exposure of components to high sintering temperatures in the range of about 1600°C to about 1850°C. f. The embodiments described herein provide a solution that can supply the high power required for high-temperature operation due to high radiative heat losses. g. The embodiments described herein include an electrical connection system that connects a power conductor and a sensor conductor to a heating element and is suitable for high-temperature use and can withstand the heater manufacturing process as disclosed herein. h. The embodiments described herein enable the ability to operate an electric heater device by incorporating or using a standard temperature control system because the resistance of the heating element does not vary significantly over temperature. Thus, by using a heating element having an electrical resistance that is relatively insensitive to temperature over the operating temperature range, the need for more complex controllers, control considerations, and switching components is avoided. i. The embodiments described herein provide a multi-zone electric heater device configured to enable an operating temperature from ambient temperature to about 850 °C. j. The embodiments described herein are resistant to etching.

[0021] The figures illustrate various embodiments of the electric heater device. For example, FIG. 1 illustrates one embodiment of an electric heater device 100 according to the present disclosure. A riser post 150 is fixed to the electric heater device 100. The riser post 150 is configured to be attached to a feed-through (not shown) that transfers the electric heater device 100 to the ambient atmosphere outside the semiconductor wafer processing chamber.

[0022] FIGS. 2-18 illustrate various aspects of the electric heater device 100. For example, the electric heater device 100 includes a disk assembly 105 and a riser post 150 fixed to the disk assembly 105. The disk assembly 105 includes one or more heating elements 110 and a thermal conduction layer 140 disposed on the upper surface 115 of the disk 120. The disk assembly 105 includes an interconnect portion 125, a thermal conduction layer 145, and a socket 135 disposed on the bottom surface 116 of the disk 120. The riser post 150 of the electric heater device 100 is generally tubular and extends vertically from the bottom surface 116 of the disk 120 after being joined to the disk assembly 105. Those skilled in the art will understand that the upper surface 115 of the disk 120 is the wafer side and the bottom surface 116 provides part of the connection to the outside of the wafer processing chamber.

[0023] The disk 120 can be configured as a disk or a flat plate and can have a circular, semi-circular or any other planar shape. According to the illustrated embodiment, the disk 120 has a circular planar shape and can be manufactured with any diameter, such as a diameter of 150 mm, 200 mm, 300 mm or 450 mm. The disk 120 can be composed of a material with thermal conductivity and electrical insulation. In the illustrated embodiment, a suitable material with thermal conductivity and electrical insulation includes aluminum nitride containing a sintering aid that can contain yttria in an amount of about 3 wt% to about 5 wt%. In other embodiments, in addition to or instead of yttria, the aluminum nitride powder can contain a small amount (i.e., less than 5 wt%) of alkaline earth metal oxides containing calcium oxide. Aluminum nitride and the sintering aid, if present, can also be combined with a suitable binder. The aluminum nitride ceramic powder containing a binder can be densified under sufficient pressure in a mold to form the disk 120. The thermal conduction layers 140, 145 of the disk assembly 105 can also be formed from aluminum nitride to ensure their thermal compatibility with each other.

[0024] The disk 120 is configured to have grooves 155 disposed on the upper surface 115 of the disk 120 to receive one or more heating elements 110. In this way, the disk 120 can function as a substrate for one or more heating elements 110. As best shown in the embodiments of FIGS. 3, 4 and 19, the grooves 155 include an inner groove 156 and an outer groove 157 defined as continuous channels each having no starting or ending point. In other embodiments, one or more of the grooves 155 can have a meandering shape or other shape with a defined end point. The inner groove 156 and the outer groove 157 of the groove 155 are further defined by a plurality of arcuate spaced channel portions that cross the upper surface 115 of the disk 120 in a zigzag manner within a common plane. In other embodiments, the groove 155 can be configured to receive a single heating element. In other embodiments, the groove 155 can be configured to receive more than two heating elements.

[0025] As shown in FIG. 3, the spaced channel portions of the outer groove 157 of the disk 120 are generally equidistant from each other in the radial direction, but at least a portion of the spaced zigzag channel portions of the inner groove 156 are closer to each other in the radial direction than other spaced zigzag channel portions of the inner groove 156. Thus, in different portions or regions of the upper surface 115 of the disk 120, the radial density of the channel portions can be made higher or lower. In some embodiments, when the channels cross the upper surface 115 of the disk 120 in an arcuate zigzag pattern radially outward from the center, the radial spacing of the arcuate zigzag channel portions can be made relatively constant with respect to each other. In other embodiments, the radial spacing of the arcuate zigzag channel portions can be different. In some embodiments, the circumferential spacing of the channel portions can be made relatively constant, varied, or made higher or lower in different portions or regions of the upper surface 115 of the disk 120.

[0026] In other embodiments, the pattern and shape of the groove 155 can include any desired pattern, depth, and width. For example, in some embodiments, the groove 155 can be arranged in a spiral pattern on the upper surface 115 of the disk 120. In some embodiments, the internal shape of the groove 155 can have a flat bottom wall and opposing side walls oriented perpendicular to the bottom wall. In other embodiments, the internal shape of the groove 155 can include slanted, conical, or rounded side walls and / or bottom walls, or any other shape. In some embodiments, to achieve optimal thermal uniformity, thermal analysis can be used to optimize the width of the channels across or locally on the disk 120.

[0027] As shown in the embodiments of FIGS. 4 and 5, one or more heating elements 110 include an inner heating element 111 and an outer heating element 112 disposed within or received by their respective inner grooves 156 and outer grooves 157. In some embodiments, one or more heating elements 110 can be embedded within or between the thermal conductive layers 140, 145 and / or the disk 120. For example, instead of forming the groove 155 in the upper surface 115 of the disk 120, the groove 155 can be disposed on the bottom surface of the thermal conductive layer 140 to receive one or more heating elements. Although a pair of heating elements are shown in these figures, in other embodiments, only one heating element or more than two heating elements can be disposed on the upper surface 115 of the disk 120. The plurality of heating elements can be controlled by a controller to provide differential heating or substantially uniform heating across the upper surface 115 of the disk 120.

[0028] At least in this embodiment, one or more heating elements 110 include equivalent compounds of refractory hard metals such as doped molybdenum or molybdenum-containing carbides, or tungsten or its alloys. Preferred doping of molybdenum requires carbon, aluminum, and optionally nitrogen, oxygen, and yttrium.

[0029] The carbon dopant is generated during the combustion of the binder while sintering the disk assembly 105 or is otherwise added to the metal powder associated with one or more heating elements 110 that are conductive. During this process, the parts are heated in an inert or substantially inert atmosphere in the range of about 1600 °C to about 1850 °C to thermally decompose the binder to produce a desired amount of residual carbon. The amount of carbon produced by this process is kept below the oxygen content of aluminum nitride not associated with yttria such that the liquid phase of alumina and yttria results in a composition where the Al2O3 / Y2O3 molar ratio of the sintered body is in the range of 10:3 to 0.1:1. A portion of this carbon is incorporated into the molybdenum powder, which shrinks and sinters to form a high-density heating element within the aluminum nitride matrix. The remaining carbon reacts with Al2O3 to form aluminum nitride and carbon monoxide. Typically, at high temperatures in the range of about 1600 °C to about 1850 °C, due to the interaction between aluminum nitride, molybdenum, carbon, and the alumina - yttria sintering aid (described above) in a nitrogen atmosphere, the composition of one or more heating elements 110 approaches chemical equilibrium, resulting in the desired composition of one or more heating elements 110. Other dopants such as aluminum, nitrogen, oxygen, and yttrium can be simply added by the high-temperature interaction between the conductive heating element component and the surrounding aluminum nitride matrix. The concentrations of carbon, aluminum, nitrogen, oxygen, and yttrium can vary within the following ranges. Carbon: 0.1 - 50 at% Aluminum: 0.1 - 20 at% Nitrogen: 0 - 20 at% Oxygen: 0 - 5 at% Yttrium: 0 - 3 at%

[0030] Note that SEM / EDS analysis may not react to trace to small amounts of boron. Usually, when there is no interference from other elements in spectral analysis, boron concentration can be detected when it exceeds 10%. Boron can exist because it is used as boron nitride (or boron nitride combined with a ceramic processable aluminum nitride) that provides inert support during the combustion and / or sintering of the binder, so it cannot be excluded from the composition candidates. Therefore, boron may be added during the high-temperature interaction during sintering as described above for dopants such as aluminum, nitrogen, and oxygen, but it may not be detected using conventional SEM / EDS analysis. Therefore, boron as a dopant within the range up to the detection limit, generally 0 to about 10 at%, cannot be excluded.

[0031] The composition of the one or more heating elements 110 includes, in addition to non-metallic elements such as carbon, nitrogen, and oxygen, trace amounts of boron, as well as elements found in aluminum nitride ceramics, namely aluminum and yttrium, all of which are determined by SEM / EDS analysis. The non-metallic elements can be added by directly adding precursors such as organic binders that result in the amount of residual carbon during the thermal decomposition in the combustion stage of the binder, or by directly adding particulate carbon incorporated only into the heating element that forms either a solid solution of molybdenum and carbon or molybdenum carbide (Mo2C or MoC). X-ray diffraction analysis showed that the heating element contains a mixture of molybdenum and molybdenum carbide and trace amounts of unidentified phases due to an insufficient number of peaks. In one case, the ratio of molybdenum to molybdenum carbide, which is Mo2C, was approximately 2:1.

[0032] The component is fired in a nitrogen atmosphere using a liquid forming oxide sintering phase (A2O3 - Y2O3), so the composition of the one or more heating elements 110 can include trace to minor amounts of aluminum, yttrium, and oxygen. Since it is well known that the addition of a small amount of dopant can affect the electrical properties of metals and ceramics (compounds of metals and non - metals), the presence of trace to minor amounts of elements within the heating element / electrode composition must be considered.

[0033] The one or more heating elements 110, as described, provide a number of highly desirable characteristics including: (1) the ability to withstand thermal stress (i.e., a coefficient of thermal expansion that is sufficiently close to that of the ceramic matrix of the disk assembly 105), (2) chemical compatibility (i.e., inertness) with respect to the ceramic matrix, (3) the ability to co - fire with the ceramic matrix, and (4), of particular note, an improvement in the stability of the electrical resistivity as a function of temperature, especially at high operating temperatures. In fact, the one or more heating elements 110, as described, have an electrical resistivity coefficient, measured from about ambient temperature to about 850 °C, that is relatively low at about 0.001 (1 / K) compared to pure molybdenum which has an electrical resistivity coefficient of 0.005 (1 / K) over the same temperature range. Thus, relatively little change in electrical resistivity (i.e., the electrical resistance is relatively insensitive to temperature changes) is observed in the desired operating range from about ambient temperature to about 850 °C. In one embodiment, as shown in FIG. 28, the electrical resistance was from about 4.18 ohms to about 4.28 ohms over a temperature range from about 300 °C to about 600 °C.

[0034] FIG. 6 shows a thermal conduction layer 140 initially disposed on the upper surface 115 of the disk 120 in the form of aluminum nitride powder. This powder is consolidated under pressure using a binder to form a machinable surface. As shown in FIG. 7, holes are drilled at three locations in the composite disk 120 / thermal conduction layer 140 to form indexing and clocking holes 122 for the disk assembly 105. As shown in FIG. 19, the holes 122 do not interfere with the one or more heating elements 110 or the interconnects 125.

[0035] The disk 120 is configured to include a groove 165 disposed on the bottom surface 116 of the disk 120 to receive the interconnect portion 125. As best shown in the embodiments of FIGS. 8-9, the groove 165 includes a heating element interconnect groove 166, an inner thermocouple interconnect groove 167, and an outer thermocouple interconnect groove 168. In the present disclosure, as shown in FIGS. 2 and 9, the interconnect portion 125 includes heating element interconnect portions 126, 129, an inner heating element thermocouple 127, and an outer heating element thermocouple 128. In some embodiments, the interconnect portion 125 can be embedded within the thermal conduction layers 140, 145 and / or within or between the disks 120. For example, instead of forming the groove 165 in the bottom surface 116 of the disk 120, the groove 165 can be disposed on the upper surface of the thermal conduction layer 140 to receive one or more heating elements.

[0036] As shown in FIG. 10, the heating element interconnect portions 126, 129 are disposed within or received by their respective interconnect grooves 166, the inner heating element thermocouple 127 is disposed within or received by the interconnect groove 167, and the outer heating element thermocouple 128 is disposed within or received by the interconnect groove 168. The groove 165 is generally arcuate and is disposed somewhat radially within a common plane. The interconnect through holes 170, 171, 172, 173 enable power to be transmitted to one or more heating elements 110 and enable sensor signals from the inner and outer thermocouples 127, 128 to pass through the disk 120 to the upper surface 115 and through conductors such as any electrodes located within the riser post and thermocouple extension wires and ultimately through a feedthrough (not shown).

[0037] Specifically, the post 146 of each heating element interconnect portion 126 is inserted into or received by its respective through hole 170 to conduct power to the outer heating element 112. One post 146 conducts electricity to the outer heating element 112, and the other post 146 returns electricity from the opposite end of the outer heating element 112 to a feedthrough (not shown) to complete the circuit.

[0038] One side of the heating element interconnecting portion 126 receives electricity at its inner end interface 130 and transmits the electricity to its post 146. The other side of the heating element interconnecting portion 126 receives electricity from its post 146 and transmits the electricity to its inner end interface 130. As shown in FIGS. 9 and 12, the inner end interface 130 receives the electricity transmitted from the respective sockets 174 inserted into the through holes 163 disposed on the inner hub 142 of the disk 120. Of course, the electricity can also flow in the reverse direction.

[0039] Similarly, the post 147 (not shown) of the heating element interconnecting portion 129 is inserted into or received by the through hole 172 and transmits power to the inner heating element 111. The post 147 transmits electricity to the inner heating element 111, and the terminal 137 returns the electricity from the opposite end of the inner heating element 111 to a feed-through (not shown) to complete the circuit.

[0040] The heating element interconnecting portion 129 receives electricity at its inner end interface 131 and transmits the electricity to its post 147. As shown in FIGS. 9 and 12, the inner end interface 131 receives the electricity transmitted from the socket 174 inserted into the through hole 162 disposed on the inner hub 142 of the disk 120. The terminal 137 transmits electricity from the opposite end of the inner heating element 111 to the socket 174 inserted into the through hole 171 disposed on the inner hub 142 of the disk 120. Of course, the electricity can also flow in the reverse direction.

[0041] The inner and outer thermocouples 127, 128 generate a millivolt signal proportional to the temperature and transmit this signal via the terminals 138 connected to the respective sockets 175 inserted into the respective through holes 164.

[0042] The composition and method for fabricating the heating element interconnects 126, 129 and the socket 135 can also be the same as the composition and method of one or more heating elements 110, such that they have the advantage of low resistance change over the operating temperature range of these components. The small electrical resistance change as disclosed herein (i.e., the electrical resistance is relatively insensitive to temperature change) minimizes the thermal effects on thermal non-uniformity. Thus, the heating element interconnects 126, 129 and the socket 135 can be doped as described for one or more heating elements 110 herein. In some embodiments, the heating element interconnects 126, 129 and the socket 135 can also not be doped, but in such a situation, the undoped heating element interconnects 126, 129 and the socket 135 must have a sufficiently low electrical resistance at all temperatures compared to one or more heating elements 110. This sufficiently low electrical resistance can be achieved, for example, by controlling the shape of the heating element interconnects 126, 129 and the socket 135 such that the electrical resistance is sufficiently small. In some embodiments, the composition of the heating element interconnects 126, 129 and the socket 135 including one or more refractory hard metals as disclosed herein may not require doping, or can be doped to at least the extent necessary for the resistive portions of each component.

[0043] As shown in FIG. 11, on the bottom surface 116 of the disk 120, a thermal conduction layer 145 in the form of aluminum nitride powder is first disposed. This powder is consolidated under pressure using a binder to form a machinable surface. As shown in FIG. 12, the bottom surface 116 is pressed and machined to form the completed thermal conduction layer 145. The socket 135 includes a heating element socket 175 and a thermocouple socket 176. FIGS. 13 to 15 show the completed disk assembly 105. The bottom surface 116 of the disk assembly 105 includes an annular groove 178 formed in an annular protrusion 180 to receive the flange 182 of the riser post 150. At this point, the hole 122 can be enlarged to its final diameter for the purpose of providing access to a wafer lifting mechanism. The socket 135 can be inserted into the disk 120 before or after sintering of the disk 120 / disk assembly 105.

[0044] FIG. 16 shows the disk assembly 105 before attaching the riser post 150, and FIGS. 17 to 18 show the disk assembly 105 after attaching the riser post 150. The riser post 150 includes a tubular extension 160 having a flange 182 at one end (upper end) and an annular protrusion 183 at the opposite end (lower end). The upper surface 184 of the flange 182 is configured to fit with the bottom wall 186 of the annular groove 178. Similarly, the outer wall 188 of the flange 182 is configured to fit with the outer wall 190 of the annular groove 178, and the inner wall 192 of the flange 182 is configured to fit with the inner wall 194 of the annular groove 178. The annular protrusion 183 is configured to engage with a feed-through (not shown) or other structure to transition to the atmospheric conditions outside the wafer processing chamber.

[0045] The riser post 150 can be joined to the disk assembly 105 using any applicable joining method so as to form a strong joint having the ability to also be a helium tight seal. For example, depending on the process requirements, diffusion bonding, metalized brazing, mechanical joining at high temperature seals, glass or glass ceramic joining methods, or other techniques can be used. One suitable joining method is disclosed in U.S. Patent No. 5,096,863 entitled "Diffusion-Bonded Assembly of AlN Ceramic Bodies and Heat Dissipation Member Constituted Thereby", which document is hereby incorporated by reference in its entirety. The joining process taught in this patent forms a helium tight seal between the riser post 150 and the disk assembly 105.

[0046] It should be noted that the electric heater device can be of any shape or configuration consistent with the principles disclosed herein. For example, some end users may require a configuration including a ground plane or an electrostatic chuck electrode embedded within the disk assembly 105. Such additional features can be easily incorporated without departing from the teachings of this specification. Also, different electrical wiring schemes can be developed to accommodate multiple heating elements and / or heating zones while minimizing the number of passthrough connections. Further, the disk assembly 105 can include a number of layers greater than the number of layers described above having interconnects for transmitting signals (i.e., power, sensors, etc.) between components on different layers.

[0047] FIG. 22 shows various manufacturing steps of one embodiment of the electric heater device 100. For example, in step 300, starting from a "green" disk 120 of a desired diameter and initial thickness, formed of a powder made of a thermally conductive and electrically insulating material such as aluminum nitride and consolidated using a binder under a sufficiently high pressure within a mold, grooves 155 for receiving one or more heating elements 110 are formed in the upper surface 115 of the disk 120, and grooves 165 for receiving the interconnect portion 125 are formed in the bottom surface 116 of the disk 120. In other embodiments, the groove 165 can be formed at a different time from the groove 155. To create the grooves 155, 165, a masking film can be applied to the respective upper surface 115 / bottom surface 116 to develop a laser engraving method. The grooves 155, 165 can also be made using other similar techniques without departing from the teachings of the present disclosure. For example, the grooves 155, 165 can also be formed within the green disk 120 when the disk 120 is first pressed and formed. Alternatively, the grooves 155, 165 can also be machined within the disk 120 after first forming the disk 120.

[0048] At this point, holes 122 can be formed to enable / ensure the clocking / indexing of disk 120 after the disk surface is covered with aluminum nitride powder. In step 305, one or more heating elements 110 are disposed within groove 155. To do this, at least one of (1) a high-concentration paint containing one or more refractory hard metals such as molybdenum, tungsten, and / or tantalum, (2) a pre-cut pattern from a polymer sheet containing one or more high-concentration refractory metals such as molybdenum, tungsten, and / or tantalum, or (3) a high-concentration powder of a refractory hard metal such as molybdenum, tungsten, and / or tantalum is applied or inserted (as specified) to fill groove 155, and these (1)-(3) all have a composition / concentration as disclosed herein, or a composition / concentration that naturally results as would be understood by one of ordinary skill in the art from the teachings disclosed herein. In step 310, a thermally conductive powder such as aluminum nitride powder is applied to the upper surface 115 of disk 120. In step 315, this powder is consolidated under pressure using a binder to form a machinable surface. In step 320, an interconnect 125 is attached to groove 165, and a high-concentration one of the powders, paints, or pre-cut patterns from polymer sheets as disclosed above, each containing one or more refractory hard metals such as molybdenum, tungsten, and / or tantalum having a composition / concentration disclosed herein, is applied or inserted to fill groove 165. In step 325, a thermally conductive powder such as aluminum nitride powder is applied to the bottom surface 116 of disk 120. In step 330, this powder is consolidated under pressure using a binder to form a machinable surface. In step 335, a power and thermocouple socket 135 is attached to each through-hole of the aluminum nitride powder on the bottom surface 116 of disk 120. In step 340, both sides of disk 120 are machined to approximately the final dimensions to form disk assembly 105. In step 345, the binder of disk assembly 105 is combusted and sintered in a nitrogen atmosphere under controlled heating to produce a small amount of residual carbon.Some of this carbon is incorporated into the molybdenum powder, which shrinks and sinters to form one or more high-density heating elements 110 within the aluminum nitride matrix. The remaining carbon reacts with Al2O3 to form aluminum nitride and carbon monoxide. Typically, at a high temperature in the range of about 1600 °C to about 1850 °C, due to the interaction between aluminum nitride, molybdenum, carbon, and the alumina-yttria sintering aid in a nitrogen atmosphere, the composition of one or more heating elements 110 approaches chemical equilibrium, resulting in the desired composition of one or more heating elements 110 being obtained.

[0049] In step 350, final machining and / or grinding is performed on the disk assembly 105 to achieve the final dimensional shape. In step 355, the riser post 150 is joined to the disk assembly 105 using any applicable joining method as disclosed herein. In step 360, the feedthrough can be assembled (if it is composed of another component), and in step 365, the feedthrough can be attached to the riser post 150.

[0050] One skilled in the art will understand that various additive manufacturing methods can be adapted to fabricate the disk assembly 105 and / or the electric heater device 100. As will be described below for the electric heater device 400, a suitable additive manufacturing process can include a process called Laminated Object Manufacturing, developed by Helysis, which forms a 3D object by laminating sheets of laser-cut paper supplied by a roll-to-roll method, and this process is hereby incorporated by reference in its entirety.

[0051] Next, FIG. 23 shows another embodiment of the electric heater device 400 of the present disclosure. In this embodiment, the disk assembly 420 includes aluminum nitride layers 401, 402, 403 including an embedded heating element 407, vias 409 and a power distribution layer 402a, a shaft 404 and feedthroughs 406, a metal chamber mounting flange 405, heating element / electrode components 411, 412, 413, and an electrode inlet point 410.

[0052] The heating element / electrode system conceptually shown as components 411, 412, 413 is used to supply current to the heating element 407 at the inlet point 410. The rigid pin 411 is a conductive metal not limited to molybdenum or tungsten since it is not joined to the inlet point 410. In some embodiments, nickel alloys can also be utilized as well. The contact between 410 and 411 forms an electrical contact for supplying current. An upward force is applied by the spring 412. The flexible conductor is connected to an external system. The flexible conductor is sealed at the feedthrough 406. This connection system can be used for heaters and thermocouple sensors. Only one set of components is shown for simplicity. This connection system allows for thermal extension of the components at high temperatures. Preferably, the aluminum metal chamber mounting flange 405 including seal components and fasteners mounts the base to a chamber wall or a lifting stage.

[0053] At least in this embodiment, the heating element 407 includes an equivalent compound of a refractory hard metal such as doped molybdenum or molybdenum-containing carbide, or tungsten or its alloy. Preferred doping of molybdenum requires carbon, aluminum, and optionally nitrogen, oxygen, and yttrium.

[0054] The carbon dopant is generated during the combustion of the binder while sintering the disk assembly 420, or is otherwise added to the metal powder associated with the conductive heating element 407. During this process, the parts are heated in an inert or substantially inert atmosphere in the range of about 1600°C to about 1850°C to thermally decompose the binder to produce a desired amount of residual carbon. The amount of carbon produced by this process is kept below the oxygen content of aluminum nitride not associated with yttria such that the liquid phase of alumina and yttria results in a composition where the Al2O3 / Y2O3 molar ratio of the sintered body is in the range of 10:3 to 0.1:1. A portion of this carbon is incorporated into the molybdenum powder, which shrinks and sinters to form a high-density heating element within the aluminum nitride matrix. The remaining carbon reacts with Al2O3 to form aluminum nitride and carbon monoxide. Typically, at high temperatures in the range of about 1600°C to about 1850°C, due to the interaction between aluminum nitride, molybdenum, carbon, and the alumina - yttria sintering aid (described above) in a nitrogen atmosphere, the composition of one or more heating elements 110 approaches chemical equilibrium, resulting in the desired composition of one or more heating elements 110. Other dopants such as aluminum, nitrogen, oxygen, and yttrium can be simply added by high-temperature interaction between the conductive heating element components and the surrounding aluminum nitride matrix. The concentrations of carbon, aluminum, nitrogen, oxygen, and yttrium can vary within the following ranges. Carbon: 0.1 - 50 at% Aluminum: 0.1 - 20 at% Nitrogen: 0 - 20 at% Oxygen: 0 - 5 at% Yttrium: 0 - 3 at%

[0055] Note that SEM / EDS analysis may not react to trace to small amounts of boron. Usually, when there is no interference from other elements in spectral analysis, boron concentration can be detected when it exceeds 10%. Boron can exist because it is used as boron nitride (or boron nitride combined with a ceramic processable aluminum nitride) that provides inert support during the combustion and / or sintering of the binder, so it cannot be excluded from the composition candidates. Therefore, boron may be added during the high-temperature interaction during sintering as described above for dopants such as aluminum, nitrogen, and oxygen, but it may not be detected using conventional SEM / EDS analysis. Therefore, boron as a dopant within the range up to the detection limit, which is generally 0 to about 10 at%, cannot be excluded.

[0056] The composition of the heating element 407 includes, in addition to non-metallic elements such as carbon, nitrogen, and oxygen, trace amounts of boron, and elements found in aluminum nitride ceramics, namely aluminum and yttrium, all of which are determined by SEM / EDS analysis. The non-metallic elements can be added by directly adding precursors such as organic binders that result in the amount of residual carbon during the thermal decomposition in the combustion stage of the binder, or by directly adding particulate carbon incorporated only into the heating element that forms either a solid solution of molybdenum and carbon or molybdenum carbide (Mo2C or MoC). X-ray diffraction analysis showed that the heating element contains a mixture of molybdenum and molybdenum carbide and trace amounts of unidentified phases due to an insufficient number of peaks. In one case, the ratio of molybdenum to molybdenum carbide, which is Mo2C, was approximately 2:1.

[0057] Since the component is fired in a nitrogen atmosphere using a liquid-forming oxide sintered phase (A2O3 - Y2O3), the composition of the heating element 407 can include trace to small amounts of aluminum, yttrium, and oxygen. Since it is well known that the addition of a small amount of dopant can affect the electrical properties of metals and ceramics (compounds of metals and non-metals), the presence of trace to small amounts of elements in the heating element / electrode composition must be considered.

[0058] The heating element 407, as described, provides a number of highly desirable characteristics including: (1) the ability to withstand thermal stress (i.e., a coefficient of thermal expansion sufficiently close to that of the ceramic matrix of the heater base disk assembly 420), (2) chemical compatibility (i.e., inertness) with the ceramic matrix, (3) the ability to co-fire with the ceramic matrix, and (4) in particular, an improvement in the stability of the electrical resistivity as a function of temperature, especially at high operating temperatures. In fact, the heating element 407, as described, has a relatively low electrical resistivity coefficient of about 0.001 (1 / K) compared to pure molybdenum, which has an electrical resistivity coefficient of 0.005 (1 / K) over the same temperature range, when measured from about ambient temperature to about 850°C. As a result, it is observed that there is relatively little change in the electrical resistivity (i.e., the electrical resistance is relatively insensitive to temperature changes) over the desired operating range of about ambient temperature to about 850°C. In one embodiment, as shown in FIG. 28, the electrical resistance was between about 4.18 ohms and about 4.28 ohms over a temperature range of about 300°C to about 600°C.

[0059] Also, the multi-layer electrical heater device as disclosed herein provides a scalable design that can prevent leakage when installed in a vacuum wafer processing chamber, accommodate multiple zones, and offers a solution where a single heating zone or multiple heating zones are possible for better temperature uniformity. This configuration also allows for the addition of one or more thermocouples, such as a temperature sensor. When a thermocouple was added between layers 402 and 403, it withstood the ceramic manufacturing process.

[0060] In addition, at the above-described concentrations of carbon, aluminum, and optionally oxygen involved in the doping of molybdenum, there was also an unexpected discovery that the sensitivity of the electrical resistance to temperature decreases, enabling significant facilitation of temperature control, chemical compatibility at high temperatures, and compatibility with an aluminum nitride substrate during co-firing / sintering of the assembly.

[0061] At least in this embodiment disclosed herein, the electric heater device 400 can be configured according to the following steps. a. Prepare a green body containing aluminum nitride (i.e., a self-supporting body formed by densifying ceramic powder using a binder under a sufficiently high pressure within a mold). Next, this green body can be machined to form a disk-shaped substrate, on which the heating element 407 can be printed and / or disposed. b. Prepare a conductive heating element composition containing molybdenum powder, an organic binder, and a solvent using any one of a plurality of known paint or paste preparation methods. Alternatively, a high-concentration one of the powders, paints, or pre-cut patterns from polymer sheets as disclosed above, containing one or more refractory hard metals such as molybdenum, tungsten, and / or tantalum, each having the composition / concentration disclosed herein, can also be prepared. c. Next, apply a masking film to one surface of the green body disk and use a laser engraving method to form a clear pattern including shallow trenches of a required depth, width, and length. d. Next, apply a molybdenum paint to uniformly fill the trenches such that the molybdenum surface and the aluminum nitride surface are at the same height with respect to a reference surface. Alternatively, apply or insert a high-concentration one of the powders, paints, or pre-cut patterns from polymer sheets as disclosed above, containing one or more refractory hard metals such as molybdenum, tungsten, and / or tantalum, each having the composition / concentration disclosed herein, to fill the trenches. Next, fill the via 409 to form a power lead connecting to the opposite surface. e. Remove the mask, check the patterns of via 409 and heating element 407 for thickness uniformity, and repair if necessary. f. Next, continuously use powder pressing in the mold and subsequent machining to enclose or embed the conductive pattern of the heating element in the multilayer disk assembly 420 structure as shown in FIG. 23. g. Alternatively, the additive manufacturing process can be adapted to encapsulate or embed the conductive pattern. Suitable additive manufacturing processes that can be adapted for this purpose include the process called thin-film lamination developed by Helysis, which forms a 3D object by laminating sheets of laser-cut paper supplied by the roll-to-roll method, and the entire process is incorporated herein by reference. By utilizing the principle of this process, a sheet of aluminum nitride can be created by ceramic fabrication processes well-known in the art, such as pressing (described herein), roll compaction, tape casting, spray deposition, etc. The surface of the sheet can be laser-cut for through-hole connections and printed with a conductive element paint. On the other hand, instead of adding powder onto the sheet with the printed conductive element pattern and pressing again, the printed sheets can be stacked on top of each other and first joined using a solvent according to the teachings of U.S. Patent No. 4,024,629 entitled "Fabrication Techniques for Multi-Layer Ceramic Modules", and this document is incorporated herein by reference in its entirety. This assembly can be further densified by warm isostatic pressing, hydroforming, or equivalent shaping techniques. The thin-film lamination method described above is highly automated to form complex 3D structures, suggesting that the process of manufacturing the electric heater device described herein can also be highly automated. It should be noted that the principle of forming two interconnected 3D structures, one being electrically insulating but thermally conductive and the other being conductive, described herein can also be extended using other additive manufacturing processes to form an aluminum nitride matrix including the internal structure of the conductive patterns such as heating elements, interconnects, sensors, etc. described herein.Other such additive manufacturing methods include binder jetting, fused filament deposition, spray deposition, and UV-curable polymers containing high concentrations of ceramic or metal powders as found in stereolithography. After fabricating a green body of aluminum nitride including internal structures as described herein such as conductive heating elements, interconnects, power leads, thermocouples, etc., the remaining process steps described below can be applied. h. Next, in a nitrogen atmosphere, combustion and sintering of the binder of the resulting disk assembly 420 are carried out. Combustion of the binder is carried out in a nitrogen environment under heating controlled such that a small amount of residual carbon is produced. The amount of carbon produced in this step is kept below the oxygen content of the aluminum nitride not related to yttria such that the liquid phases of alumina and yttria result in a composition where the Al2O3 / Y2O3 molar ratio of the sintered body is between 10:3 and 0.1:1. Part of this carbon is incorporated into the molybdenum powder, and this molybdenum powder shrinks and sinters to form a high-density heating element / electrode within the aluminum nitride matrix. As described above, during sintering, due to the high-temperature interaction between the heating element 407, the via 409, and the surrounding aluminum nitride matrix containing an alumina-yttria phase that functions as a sintering aid during sintering, other dopants such as aluminum, nitrogen, oxygen, yttrium, and optionally boron are added. The remaining carbon reacts with Al2O3 to form aluminum nitride and carbon monoxide. Typically, at high temperatures in the range of about 1600 °C to about 1850 °C, due to the interaction between aluminum nitride, molybdenum, carbon, and the alumina-yttria sintering aid in a nitrogen atmosphere, the composition of one or more heating elements 110 approaches chemical equilibrium, resulting in the desired composition of one or more heating elements 110. This description is directed to the fabrication of a sintered aluminum nitride disk heater. Next, this disk assembly 420 is machined to the final dimensions required for joining to the hollow / tubular shaft 404 and post-joining operations. i. Prepare a hollow / tubular shaft 404 from aluminum nitride using known processes suitable for fabricating articles from aluminum nitride and machine it to its final form. Specifically, machine the hollow / tubular shaft 404 by following standard processes for sintering aluminum nitride ceramics, i.e., pressing the powder into a tubular preform, machining this preform to form a green body of the desired shape and dimensions, and then performing binder burnout and sintering. Next, machine the sintered part to the final dimensions required to form a hollow / tubular shaft 404 that is ready to be joined to the disk assembly 420. j. Attach the sintered hollow / tubular shaft 404 and the sintered aluminum nitride disk assembly 420 to each other using any applicable joining method. For example, depending on the process requirements, diffusion bonding, metallized brazing, mechanical joining with a high-temperature seal, glass or glass-ceramic joining, or other techniques can be used. One suitable joining method is disclosed in U.S. Patent No. 5,096,863 entitled "Diffusion Bonding Assembly of AlN Ceramic Bodies and Heat Dissipating Members Composed Thereby", which is hereby incorporated by reference in its entirety. k. Purge the volume inside the tubular shaft 404 with an inert gas to prevent oxidation of the components. l. Attach a power electrode system conceptually shown by components 411, 412, 413 to supply current to the heating element 407 at the inlet point 410. m. Connect a flexible conductor to an external system and seal it at the feedthrough 406. n. For simplicity, only one set of heating elements 407 and thermocouple sensors is shown, but in other embodiments, multiple heating elements and thermocouple sensors can also be arranged. o. This connection system allows for thermal expansion of the components at high temperatures.

[0062] This unique manufacturing method can include the use of an additive manufacturing process using a granular composition for most components, a controlled binder combustion process, and sintering of the base disk, resulting in a solution with unexpected results as disclosed herein.

[0063] Next, FIG. 24 shows a graph of the electrical resistivity as a function of temperature for pure tungsten and pure molybdenum, which shows that the electrical resistivity steadily increases over a range of temperatures from about 0 °C to about 3400 °C for tungsten and from about 0 °C to about 2200 °C for molybdenum.

[0064] FIGS. 25 and 26 show SEM / EDS spectral analysis and representative elemental concentrations in the vicinity of the heating element / electrode within a sample disk assembly configured as disclosed herein. The spectral lines for palladium and gold are due to the thin conductive film coating of the sample. In this sample, as shown in FIG. 26, the weight percent of molybdenum was 70.8%, carbon was 20.6%, oxygen was 3.6%, nitrogen was 3.1%, aluminum was 1.9%, and yttrium was 0.0%.

[0065] FIG. 27 shows a plot of power versus temperature by thermal simulation. This type of plot can be useful for sizing components and selecting an appropriate control system. At high-temperature operation, high power is required due to radiative heat loss. The Stefan-Boltzmann law for radiative heat transfer shows a non-linear increase (to the fourth power) with temperature. The embodiments disclosed herein supply high power for high-temperature operation in the range of about 600 °C to about 800 °C due to the high radiative heat loss as shown in FIG. 27.

[0066] FIG. 28 shows resistance data taken from a representative heating element of the present disclosure. This data shows that the resistance is stable at high temperatures, i.e., about 500 °C to about 600 °C, and somewhat stable from about 300 °C to about 500 °C. The fluctuations are due to power variations and heating of the conductor. The resistance is calculated from voltage and current readings.

[0067] The embodiments described in this specification are possible implementation examples and are merely shown so as to clearly understand the principles of the features described in this specification. Many variations and modifications can be made to the above-described (single or multiple) embodiments without substantially departing from the spirit and principles of the technologies, processes, devices, and systems described in this specification. In this specification, all such modifications are intended to be included within the scope of this disclosure and to be protected by the following claims.

Claims

1. 1. An electric heater apparatus for use in processing a semiconductor wafer in a wafer processing chamber, comprising: a first thermally conductive layer including an electrically insulating material, a top surface and a bottom surface; one or more electrically conductive heating elements disposed within respective ones of one or more grooves disposed on the top surface of the first thermally conductive layer; a second thermally conductive layer disposed on the top surface of the first thermally conductive layer over the one or more heating elements; the one or more heating elements comprise one or more refractory hard-metals doped with at least one of carbon, nitrogen, aluminum, yttrium, or oxygen, the doped one or more refractory hard-metals having electrical resistance less dependent on temperature than undoped refractory hard-metals over an operating temperature range from ambient temperature to about 850° C., and the one or more heating elements are independently controllable to provide one or more heating zones along the top surface of the first thermally conductive layer. Electric heating device.

2. The electric heater apparatus of claim 1 , wherein the first thermally conductive layer comprises a disk.

3. 10. The electric heater apparatus of claim 1, wherein the first thermally conductive layer is sintered and the one or more heating elements initially comprise a high concentration of a powder, paint, or a pre-cut pattern from a polymeric sheet prior to sintering the first thermally conductive layer.

4. 2. The electric heater apparatus of claim 1, wherein the concentration of carbon can vary from about 0.1 at% to about 50 at%, the concentration of aluminum can vary from about 0.1 at% to about 20 at%, the concentration of nitrogen can vary from about 0 at% to about 20 at%, the concentration of oxygen can vary from about 0 at% to about 5 at%, and the concentration of yttrium can vary from about 0 at% to about 3 at%.

5. The electric heater apparatus of claim 1 , wherein the first thermally conductive layer comprises aluminum nitride.

6. 2. The electric heater apparatus of claim 1 including a third thermally conductive layer disposed on said bottom surface of said first thermally conductive layer, said third thermally conductive layer including a hub.

7. 7. The electric heater apparatus of claim 6, wherein said second and third thermally conductive layers comprise aluminum nitride.

8. The electric heater apparatus of claim 6 including a sintered riser attached to said hub.

9. 7. The electric heater apparatus of claim 6 including a sintered riser bonded to said hub, said bonded riser forming a helium tight seal with said hub.

10. 7. The electric heater apparatus of claim 6, including one or more electrical interconnects disposed within each of one or more channels disposed in the bottom surface of the first thermally conductive layer.

11. 11. The electric heater apparatus of claim 10, wherein the interconnect is configured to conduct electricity in a circuit from the hub to the one or more heating elements and from the one or more heating elements to the hub.

12. The electric heater apparatus of claim 10 , wherein the interconnect is configured to convey sensor data from one or more temperature sensors to the hub.

13. 13. The electric heater apparatus of claim 12, wherein the one or more temperature sensors are disposed within respective channels of one or more channels disposed on the bottom surface of the first thermally conductive layer and below the third thermally conductive layer.

14. 14. The electric heater apparatus of claim 13, wherein the third thermally conductive layer is disposed over the one or more temperature sensors.

15. 10. The electric heater device of claim 1, wherein the one or more heating elements and the first thermally conductive layer have functionally similar coefficients of thermal expansion to avoid deleterious cracks or fissures in the electric heater device.

16. 1. An electric heater apparatus for use in processing a semiconductor wafer in a wafer processing chamber, comprising: a sintered disk including a thermally conductive and electrically insulating material, a top surface and a bottom surface; one or more electrically conductive heating elements disposed within each of one or more grooves disposed in the top surface of the disk; a first thermally conductive layer disposed on the top surface of the disk over the one or more heating elements; one or more interconnects disposed within each of the one or more channels disposed on the bottom surface of the disk; a second thermally conductive layer including a hub disposed on the bottom surface of the disk over the one or more interconnects; Including, the one or more heating elements include one or more refractory hard metals doped with at least one of carbon, nitrogen, aluminum, yttrium, or oxygen, the doped one or more refractory hard metals having electrical resistance less dependent on temperature than undoped refractory hard metals over an operating temperature range from ambient temperature to about 850° C., the one or more heating elements being independently controllable to provide one or more heating zones along the top surface of the disk; the one or more conductive heating elements are protected from chemical attack; Electric heating device.

17. 17. The electric heater apparatus of claim 16, wherein the concentration of carbon can vary from about 0.1 at% to about 50 at%, the concentration of aluminum can vary from about 0.1 at% to about 20 at%, the concentration of nitrogen can vary from about 0 at% to about 20 at%, the concentration of oxygen can vary from about 0 at% to about 5 at%, and the concentration of yttrium can vary from about 0 at% to about 3 at%.

18. 17. The electric heater apparatus of claim 16, wherein said thermally conductive and electrically insulating material is aluminum nitride.

19. 17. The electric heater apparatus of claim 16, wherein the first and second thermally conductive layers comprise aluminum nitride.

20. 17. The electric heater apparatus of claim 16 including a riser attached to the hub.

21. 21. The electric heater apparatus of claim 20, wherein the riser is bonded to the hub, the bonded riser forming a helium tight seal with the hub.

22. the interconnects include one or more electrical interconnects configured to conduct electricity in a circuit from the hub to the one or more heating elements and from the one or more heating elements to the hub; 17. An electric heater device according to claim 16.

23. 17. The electric heater apparatus of claim 16, comprising one or more temperature sensors disposed within the one or more channels.

24. 24. The electric heater apparatus of claim 23, wherein the second thermally conductive layer is disposed over the one or more temperature sensors.

25. 17. The electric heater apparatus of claim 16, wherein the one or more heating elements and the disk have functionally similar coefficients of thermal expansion to avoid deleterious cracks or fissures in the electric heater apparatus.

26. 17. The electric heater apparatus of claim 16, wherein the one or more heating elements are independently controllable to provide one or more heating zones along the top surface of the disk.

27. 1. A method of manufacturing an electric heater apparatus for use in processing semiconductor wafers in a wafer processing chamber, comprising: providing a disk comprising an aluminum nitride having a sintering aid comprising about 3 to about 5 wt % yttria, a top surface and a bottom surface; creating one or more grooves in the top surface of the disk; depositing one or more electrically conductive heating elements within each of one or more grooves disposed on the top surface of the disk; Including, the one or more heating elements include one or more refractory hard metals doped with at least one of carbon, nitrogen, aluminum, yttrium, or oxygen, the doped one or more refractory hard metals having electrical resistance less dependent on temperature than undoped refractory hard metals over an operating temperature range from ambient temperature to about 850° C., the one or more heating elements being independently controllable to provide one or more heating zones along the top surface of the disk; The method for manufacturing the electric heater device further includes: depositing a first powder comprising aluminum nitride on the top surface of the disk over the one or more heating elements; pressing the disk at least once in a die to consolidate the first powder; creating one or more channels in the bottom surface of the disk; depositing one or more conductive interconnects within the one or more channels on the bottom surface of the disk; depositing a second powder comprising aluminum nitride on the bottom surface of the disk over the one or more interconnects; pressing the disk at least once in a die to consolidate the second powder; machining and grinding the pressed disk to include a hub, the pressed and machined disk defining an aluminum nitride matrix having embedded heating elements and interconnects; Sintering the aluminum nitride matrix at a temperature in the range of about 1600° C. to about 1850° C., the sintering being carried out in a nitrogen environment under controlled heating to combust any temporary binders in the aluminum nitride matrix, and the amount of carbon is determined by the liquid phase of alumina and yttria being reduced to Al in the sintered aluminum nitride matrix. 2 O 3 / Y 2 O 3 a sintering step in which the oxygen content of the aluminum nitride not associated with yttria in the aluminum nitride matrix is ​​maintained below that of the aluminum nitride in a composition such that the molar ratio is between 10:3 and 0.1:1, and a portion of the amount of carbon is incorporated into the doped refractory hard metal(s) of the one or more electrically conductive heating elements, and upon sintering a densified aluminum nitride matrix is ​​formed containing one or more electrically conductive heating elements densified within the sintered aluminum nitride matrix; and joining the sintered riser to the hub. A method for manufacturing an electric heater device.

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