Beryllium oxide pedestals

Abstract

To provide ceramic pedestals comprising beryllium oxide for high temperature applications, and production methods thereof.SOLUTION: In a pedestal assembly, a base plate has a top and a bottom and comprises a beryllium oxide composition containing at least 95 wt.% of beryllium oxide and optionally fluorine / fluoride ions. The base plate demonstrates a clamping pressure of at least 133 kPa at a temperature of at least 600°C and a bulk resistivity greater than 1×105 ohm-m at 800°C.SELECTED DRAWING: None

Description

Technical Field

[0001] Cross - reference to Related Applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 887,282, filed on August 15, 2019, the entire content of which is incorporated herein by reference.

[0002]

[0002] This disclosure relates to ceramic pedestals for high - temperature applications. Specifically, this disclosure relates to pedestals containing beryllium oxide for use in semiconductor manufacturing processes.

Background Art

[0003]

[0003] In many high - temperature substrate processing applications, the substrate is processed, e.g., etched, coated, cleaned, and / or its surface energy is activated, in a high - temperature processing chamber. To perform the processing, a process gas is introduced into the processing chamber and then energized to achieve a plasma state. The energization can be performed by applying an RF voltage to an electrode, e.g., a cathode, and electrically grounding the anode to form a capacitive region in the processing chamber. The substrate is then processed by the plasma generated in the processing chamber, and etched or a material is deposited thereon.

[0004]

[0004] During this processing, the substrate must be supported (and held in a predetermined position). In many cases, a ceramic pedestal is used to achieve this goal. In some examples, an electrostatic chuck assembly (as part of the pedestal) is used to hold the substrate in a predetermined position. Other support mechanisms, e.g., mechanical and vacuum, are also known. An electrostatic chuck often comprises an electrode covered with a dielectric. When the electrode is charged, opposite electrostatic charges in the substrate and the resulting electrostatic force cause the substrate to be gripped by the electrostatic chuck. Once the substrate is firmly gripped by the chuck, the plasma processing proceeds.

[0005]

[0005] Some known plasma processes are often carried out in a highly erosive gas at a certain elevated temperature. For example, while aluminum etching is performed at a temperature of 100°C to 200°C, the process of etching copper or platinum is carried out at a temperature of 250°C to 600°C. These temperatures and erosive gases thermally degrade the materials used in the manufacture of the chuck. Conventional ceramic pedestals have used, as the main components, various oxides, nitrides, and alloys, such as aluminum nitride, aluminum oxide, silicon dioxide, silicon carbide, silicon nitride, sapphire, zirconia, or graphite, or anodized metal. In some cases, these requirements can be met by conventional ceramic materials, such as aluminum oxide or aluminum nitride.

[0006]

[0006] However, as technology advances, higher substrate processing operating conditions (temperatures), such as above 650°C, above 750°C, or above 800°C, are desired. Unfortunately, it has been found that conventional ceramic pedestal materials suffer from structural problems, such as decomposition, thermal and / or mechanical degradation, pulverization, and delamination, at these elevated temperatures.

[0007]

[0007] In addition, it has been found that conventional ceramic pedestals demonstrate inconsistent temperature uniformity across the pedestal plate surface during operation, probably due to the inherent properties of aluminum nitride, silicon dioxide, or graphite. This leads to non - uniformity problems in the processes applied to semiconductor wafers. In conventional pedestal plates, attempts have been made to improve temperature uniformity. However, these attempts involve more complex heating setups and control mechanisms, such as an increase in the number of heating zones and thermocouples, which increase costs and the uncertainties of the forming process. Thermal settings and control mechanisms, such as an increase in the number of heating zones and thermocouples, are involved, and costs and the uncertainties of the forming process increase.

[0008]

[0008] In addition, conventional non-beryllium pedestals struggle to apply sufficient chucking force (clamping pressure) required to hold a wafer in a predetermined position, especially at high temperatures. Conventional pedestals are also troubled by problems related to micro-destruction, surface pulverization, (thermal) decomposition, and low permeability during temperature rise. Even at moderate temperatures, conventional pedestals have a problem of non-chucking time, probably due to their large capacity.

[0009]

[0009] Furthermore, many conventional pedestals use, for example, a laminated structure that relies on adhesive bonding using brazing materials, or a laminated structure through diffusion bonding, to fix metal conductors in a plurality of (ceramic) layers. However, such laminated structures are repeatedly troubled by structural problems and delamination resulting from the stress of operation at high temperatures in many cases.

[0010]

[0010] Also, it may be desirable to rapidly cool the substrate in order to maintain the substrate within a narrow temperature range, or to clean the pedestal, substrate, or chamber. However, due to the coupling of RF energy and the variation in plasma ion density across the entire substrate, temperature fluctuations occur in a strong plasma. These temperature fluctuations can cause rapid increases or decreases in the temperature of the substrate and require stabilization. Therefore, it is desirable to have a pedestal that requires only slight cooling or no cooling during cleaning, for example, can be cleaned at the operating temperature, and / or can be cleaned with a slight cleaning cycle time or without a cleaning cycle time, (advantageously improving the processing efficiency by reducing / eliminating downtime).

[0011]

[0011] Considering conventional pedestal technologies, there is a need for an improved pedestal assembly that has improved performance, demonstrating, especially at high temperatures, for example above 650 °C, that decomposition is reduced, heat is reduced, micro-destruction is reduced, and / or mechanical degradation is reduced, temperature uniformity is improved, and / or clamping pressure is excellent, while having no delamination.

Brief Description of the Drawings

[0012]

Figure 1

[0012] FIG. 1 is a graph showing the thermal diffusivity of the examples and comparative examples plotted over a temperature range of 0°C to 900°C.

Figure 2

[0013] FIG. 2 is a graph showing the specific heat of the examples and comparative examples plotted over a temperature range of 0°C to 900°C.

Figure 3

[0014] FIG. 3 is a graph showing the thermal conductivity of the examples and comparative examples plotted over a temperature range of 0°C to 900°C.

Figure 4

[0015] FIG. 4 is a graph showing the permeability of the examples and comparative examples plotted over a temperature range of 0°C to 850°C.

Figure 5

[0016] FIG. 5 is a graph showing the bulk resistivity of the examples and comparative examples plotted over a temperature range of 0°C to 850°C.

Figure 6

[0017] FIG. 6 is a graph showing the bulk resistivity of the examples and comparative examples plotted over a temperature range of 0°C to 850°C.

SUMMARY OF THE INVENTION

[0013]

[0018] In some embodiments, the present disclosure is a pedestal assembly comprising a shaft and a base plate, wherein the shaft contains a first beryllium oxide composition containing beryllium oxide and (1 ppb to 1000 ppm or 10 ppb to 800 ppm) fluorine / fluoride ions, and the base plate contains a second beryllium oxide composition containing at least 95 wt% beryllium oxide and optional fluorine / fluoride ions relates to a pedestal assembly. The base plate has a clamping pressure of at least 133 kPa and / or a bulk resistivity greater than 1×10 5 ohm-m at 800°C To demonstrate. The first beryllium oxide composition may contain more fluorine / fluoride ions than the second beryllium oxide composition and may be treated to achieve the fluorine / fluoride ion concentration. The first beryllium oxide composition may contain less than 50 wt% magnesium oxide and less than 50 wt% ppm silicon dioxide and / or 1 - 50 wt% ppm alumina; 1 ppb - 10000 ppm sulfite; and / or 1 ppb - 1 wt% ppm boron, barium, sulfur, or lithium, or combinations thereof (including oxides, alloys, composites, or allotropes, or combinations thereof). The first beryllium oxide composition may have an average grain boundary greater than 0.1 micron and / or an average particle size less than 100 microns. The second beryllium oxide composition may further contain 1 ppb - 10 wt% ppm magnesium oxide and 1 ppb - 10 wt% ppm silicon dioxide and / or 1 ppb - 10 wt% magnesium trisilicate and / or 1 ppb - 1 wt% lithium oxide. The first beryllium oxide composition may contain more magnesium oxide and / or magnesium trisilicate than the second beryllium oxide composition. The first beryllium oxide composition may contain less than 75 wt% aluminum nitride, and / or the second beryllium oxide composition may contain less than 5 wt% aluminum nitride. The first beryllium oxide composition may have a conductivity less than 300 W / m-K at room temperature and / or a theoretical density in the range of 90% - 100%, and / or the second beryllium oxide composition may have a conductivity less than 400 W / m-K at room temperature. The base plate has a temperature variation of less than ±3% when heated to a temperature above 700 °C, and / or at 800 °C 1×10 4It is possible to demonstrate a bulk resistivity of more than Ohm·m, and / or a corrosion loss of less than 0.016 wt%, and / or a dielectric constant of less than 20, and / or a surface hardness of at least 50 Rockwell on the 45N scale, and / or a coefficient of thermal expansion in the range of 5 to 15 over the entire base plate, and / or the minimum transverse dimension of the base plate is at least 100 mm, and / or it can have a flatness with a camber of less than 50 microns over a distance of 300 mm. The base plate may further include a heating element sealed within the base plate and / or optionally a mesa having a height of less than 1 micron. The base plate may include less than two laminates and / or may not include individual layers. The shaft may be provided with a stub portion having a similar coefficient of thermal expansion.

[0014]

[0019] The present disclosure also relates to a base plate comprising a beryllium oxide composition having upper and lower portions and containing at least 95 wt% beryllium oxide and optionally fluorine / fluoride ions. The base plate has a clamping pressure of at least 133 kPa at a temperature of at least 600 °C and / or a decomposition change of less than 1 wt% at a temperature above 1600 °C, and / or a temperature variation of less than ±3% when heated to a temperature above 700 °C, and / or 1×10 8 more than Ohm·m bulk resistivity, and / or a corrosion loss of less than 0.016 wt%, and / or a dielectric constant of less than 20, and / or a surface hardness of at least 50 Rockwell on the 45N scale, and / or 1×10 at 800 °C 5Bulk resistivity exceeding Ohm m, and / or a coefficient of thermal expansion in the range of 5 to 15 over the entire base plate (the coefficient of thermal expansion may vary by less than 25% from the top to the bottom), and / or a cleaning cycle time of less than 2 hours, and / or a temperature variation of less than ±3% can be demonstrated. The base plate may include a beryllium oxide composition containing magnesium oxide in the range of 1 ppb to 10 wt% ppm, for example, 1 ppm to 5 wt%, and silicon dioxide in the range of 1 ppb to 10 wt% ppm, for example, 1 ppm to 5 wt%, and / or magnesium trisilicate in the range of 1 ppb to 10 wt% ppm, for example, 1 ppm to 5 wt%. The base plate may not include individual layers, and may have a decreasing thermal conductivity gradient from the top to the bottom, and / or a decreasing resistivity gradient from the top to the bottom, and / or a decreasing purity gradient from the top to the bottom, and / or a decreasing theoretical density gradient from the top to the bottom and / or an increasing dielectric constant gradient from the top to the bottom. The base plate may further include an optional heating element containing niobium and / or platinum, an optional coiled and / or crimped heating element, and / or an antenna. The purity of the upper part may be at least 0.4% higher than the purity of the lower part. The base plate may further include an optional heating element containing niobium and / or platinum, an optional coiled and / or crimped heating element, and / or an antenna. The purity of the upper part may be at least 0.4% higher than the purity of the lower part.

[0015]

[0020] The present disclosure also relates to a base plate having an upper portion and a lower portion and including a beryllium oxide composition, where the base plate has a thermal conductivity gradient that decreases from the upper portion to the lower portion, and / or a resistivity gradient that decreases from the upper portion to the lower portion, and / or a purity gradient that decreases from the upper portion to the lower portion, and / or a theoretical density gradient that decreases from the upper portion to the lower portion and / or a dielectric constant gradient that increases from the upper portion to the lower portion. The base plate, when measured at room temperature, has an upper thermal conductivity in the range of 125 to 400 W / mK, a lower thermal conductivity in the range of 146 W / mK to 218 W / mK, and / or when measured at 800 °C, has an upper thermal conductivity in the range of 25 W / mK to 105 W / mK, a lower thermal conductivity in the range of 1 W / mK to 21 W / mK, optionally, when measured at room temperature, the upper thermal conductivity is at least 6% higher than the lower thermal conductivity, and / or optionally, when measured at 800 °C, the upper thermal conductivity is at least 6% higher than the lower thermal conductivity. The upper purity may be in the range of 99.0 to 99.9, and the lower purity may be in the range of 95.0 to 99.5. The upper purity may be at least 0.4% higher than the lower purity. The upper theoretical density may be in the range of 93% to 100%, and the lower theoretical density may be in the range of 93% to 100%. The upper theoretical density may be at least 0.5% higher than the lower theoretical density. The upper dielectric constant may be in the range of 1 to 20, and the lower dielectric constant may be in the range of 1 to 20. The base plate may not include individual layers. The base plate can demonstrate the above-mentioned clamping pressure, temperature variation, and corrosion loss.

[0016]

[0021] The present disclosure also relates to a shaft for a pedestal assembly comprising beryllium oxide and a beryllium oxide composition containing (10 ppb to 800 ppm) fluorine / fluoride ions. The beryllium oxide composition has an average grain boundary of more than 0.1 micron, and / or an amorphous granular structure, and / or an average particle size of less than 100 microns, and / or can demonstrate a thermal conductivity of less than 300 W / m-K at room temperature, and / or a theoretical density in the range of 90 to 100. The shaft can demonstrate an upper thermal conductivity in the range of 146 W / mK to 218 W / mK and a lower thermal conductivity in the range of 1 W / mK to 218 W / mK when measured at room temperature, and / or an upper thermal conductivity in the range of 1 W / mK to 21 W / mK and a lower thermal conductivity in the range of 1 W / mK to 21 W / mK when measured at 800 °C, and the upper theoretical density may be at least 0.5% higher than the lower theoretical density. The beryllium oxide composition may contain less than 75 wt% aluminum nitride. The first beryllium oxide composition may contain 1 ppb to 1000 ppm fluorine / fluoride ions, and / or less than 50 wt% magnesium oxide, and / or less than 50 wt% ppm silicon dioxide, and / or 1 ppb to 50 wt% ppm alumina, and / or 1 ppb to 10000 ppm sulfite, and / or 1 ppb to 1 wt% ppm boron, barium, sulfur, or lithium, or a combination thereof (including oxides, alloys, composites, or allotropes, or a combination thereof).

[0017]

[0022] The present disclosure also relates to a pedestal assembly comprising a shaft of any of the above-described embodiments and a base plate containing a multilayer (optionally having a brazing material) joined to each other and an optional printed heating element.

[0018]

[0023] The present disclosure also relates to a base plate having an upper and a lower portion and containing a ceramic composition, where the base plate has a clamping pressure of at least 133 kPa, a temperature variation of less than ±3 °C when heated to a temperature above 700 °C, and / or 1 × 10 at 800 °C 8Ultra bulk resistivity, and / or corrosion loss of less than 0.016 wt%, and / or a dielectric constant of less than 2, and / or a surface hardness of at least 50 Rockwell on the 45N scale, and / or a coefficient of thermal expansion in the range of 5 to 15 across the entire base plate.

[0019]

[0024] The present disclosure also relates to a method of manufacturing a base plate, the method comprising supplying a first BeO powder and a third BeO powder; forming a second powder from the first and third powders; forming a first (lower) region from the first powder; forming a second (middle) region from the second powder; forming a third (upper) region from the third powder to form a base plate precursor, wherein the second region is disposed between the first and third regions; optionally mixing the base plate precursor to bond the powders; optionally placing a heating element within a region and / or crimping an end; cold forming the base plate precursor; and firing the base plate precursor to form the base plate. The first and third (and second) powders may comprise different grade starting BeO.

[0020]

[0025] The present disclosure also relates to a method of manufacturing a pedestal shaft, the method comprising treating a beryllium oxide composition to achieve a fluorine / fluoride ion concentration in the range of 1 ppb to 1000 ppm fluorine / fluoride ions.

[0021]

[0026] The present disclosure also relates to a method of cleaning a contaminated pedestal assembly, the method comprising the steps of providing a pedestal assembly and a wafer, the wafer being disposed on top of the pedestal assembly; heating the wafer to a temperature above 600°C; cooling the wafer to a cooling temperature (or not cooling it at all) with a width of less than 100°C; cleaning the plate at the cooling temperature; and optionally reheating the wafer to 600°C, wherein a cleaning cycle time from the cooling step to the reheating step is less than 2 hours. The cleaning cycle time may range from 0 to 10 minutes.

DETAILED DESCRIPTION OF THE INVENTION

[0022]

[0027] As described above, conventional pedestal assemblies are often used to support and hold a semiconductor substrate in place during processing, such as chemical vapor deposition, etching, etc. Typical ceramic pedestals have used various oxides, nitrides, and alloys, such as aluminum nitride, aluminum oxide, silicon dioxide, or graphite, as their main components. These ceramic materials can meet the requirements of processing methods at medium to high temperatures, e.g., temperatures below 650°C or below 600°C. However, as technology advances, higher substrate processing operation temperatures, e.g., above 650°C or even above 800°C, are desired. Unfortunately, it has been found that conventional ceramic pedestal materials suffer from structural problems, such as decomposition, thermal and / or mechanical degradation, and delamination, under such high temperatures. In addition, conventional pedestal materials are known to have insufficient bulk resistivity. In some cases, the unsatisfactory resistivity leads to insufficient chucking / clamping force required to hold the wafer in place, especially at high temperatures.

[0023]

[0028] Furthermore, it has been found that conventional ceramic pedestals demonstrate inconsistent temperature uniformity across the entire surface of the pedestal plate, which leads to inconsistencies that are problematic in the processes applied to semiconductor wafers. Additionally, many of the conventional layered pedestal structures have been found to suffer from structural problems and delamination that often result from the stresses of high-temperature operation.

[0024]

[0029] The inventors have now discovered that the use of the disclosed beryllium oxide (BeO) compositions (having high purity levels and phase component contents) results in a pedestal assembly (or pedestal base plate and shaft components) that demonstrates a synergistic combination of high-temperature performance and high chucking force (“clamping pressure”) that may be related to resistivity. Without being bound by theory, it is envisioned that a combination of some specific components of the BeO composition (optionally, at the component concentrations of the present disclosure) in combination with optional specific processing parameters results in advantageous microstructures in the BeO, such as grain boundaries and grain size, and thus, a combination of high-temperature performance and high clamping pressure. Also, without being bound by theory, the BeO compositions of the present disclosure result in pedestal base plates having an optimal (lesser) amount of magnesium oxide, silicon dioxide, and / or magnesium trisilicate, which contributes to a high bulk resistivity.

[0025]

[0030] The inventors have also found that some of the disclosed beryllium oxide (BeO) compositions (optionally, at the component concentrations of the present disclosure) unexpectedly result in advantageous microstructures (discussed in more detail herein) when combined with specific processing parameters.

[0026]

[0031] Furthermore, it has been discovered that the components of the BeO composition result in a low dielectric constant, which leads to a low capacitance and, in turn, an improvement in the non-chucking time delay. The BeO compositions of the present disclosure also demonstrate improved corrosion resistance, improved thermal penetration rate, improved thermal diffusivity, improved thermal conductivity, improved specific heat, and lower thermal hysteresis, all of which have also been found to contribute to the synergistic effect of the performance disclosed herein.

[0027]

[0032] Conventional ceramic pedestals, for example, those formed using aluminum nitride, aluminum oxide, silicon dioxide, silicon carbide, silicon nitride, sapphire, zirconia, anodized metal, or graphite as the main component, were unable to achieve high-temperature performance. It was also not possible to achieve the clamping pressure tolerated at such temperatures, i.e., it was discovered that the clamping pressure was lacking / reduced, especially at high temperatures.

[0028] Pedestal Assembly

[0033] Disclosed herein is a pedestal assembly. The pedestal assembly includes a base plate disposed on or at the top of a shaft. The shaft contains (and is formed from) a first BeO composition containing BeO as well as fluoride ions and / or fluorine. The base plate contains (and is formed from) a second BeO composition containing BeO (at a high purity level such as at least 95.0 wt%) and optionally fluoride ions and / or fluorine. The BeO in the compositions of the present disclosure is, in some embodiments, synthetic BeO, e.g., BeO manufactured from raw materials (powders), which is in contrast to solid natural BeO existing in nature. The inventors have clarified that using beryllium oxide (and optionally other components described herein) as the main component in the composition results in or contributes to the performance characteristics described herein, such as high-temperature performance and / or excellent clamping pressure.

[0029]

[0034] In some embodiments, the pedestal assembly (or its base plate) of the present disclosure demonstrates a wide range of clamping pressure performance. In some cases, the pedestal assembly of the present disclosure is a Johnsen-Rahbek pedestal. For example, the pedestal assembly of the present disclosure can demonstrate a clamping pressure of more than 133 kPa, such as more than 135 kPa, more than 140 kPa, more than 145 kPa, or more than 150 kPa. Regarding the upper limit, the pedestal assembly can demonstrate a clamping pressure of less than 160 kPa, such as less than 155 kPa, less than 150 kPa, less than 145 kPa, less than 140 kPa, or less than 135 kPa. Regarding the range, the pedestal assembly can demonstrate a clamping pressure in the range of 133 kPa to 160 kPa, such as 133 kPa to 155 kPa, 133 kPa to 150 kPa , a clamping pressure in the range of 135 kPa to 150 kPa, 135 kPa to 145 kPa, or 138 kPa to 143 kPa.

[0030]

[0035] As used herein, terms such as "more than ~", "less than ~" are considered to include the real number limit and are interpreted as, for example, "equal to or more than ~". The range is considered to include the endpoint values.

[0036] In other cases, the pedestal assembly of the present disclosure is a coulombic pedestal. For example, the pedestal assembly of the present disclosure can demonstrate a clamping pressure of more than 0.1 kPa, such as more than 0.5 kPa, more than 1 kPa, more than 1.3 kPa, more than 2 kPa, or more than 4 kPa. Regarding the upper limit, the pedestal assembly can demonstrate a clamping pressure of less than 15 kPa, such as less than 14 kPa, less than 13 kPa, less than 12 kPa, or less than 10 kPa. Regarding the range, the pedestal assembly can demonstrate a clamping pressure in the range of 0.1 kPa to 15 kPa, such as 0.5 kPa to 14 kPa, 1 kPa to 14 kPa, 1.3 kPa to 13 kPa, 2 kPa to 12 kPa, or 4 kPa to 10 kPa.

[0031]

[0037] In other cases, the pedestal assembly of the present disclosure is a partial Johnsen-Rahbek / partial Coulomb pedestal. For example, the pedestal assembly of the present disclosure can demonstrate a clamping pressure greater than 0.1 kPa, such as greater than 1 kPa, greater than 10 kPa, greater than 13 kPa, greater than 20 kPa, greater than 40 kPa, or greater than 60 kPa. Regarding the upper limit, the pedestal assembly can demonstrate a clamping pressure less than 160 kPa, such as less than 155 kPa, less than 135 kPa, less than 133 kPa, less than 130 kPa, less than 120 kPa, less than 100 kPa, or less than 80 kPa. Regarding the range, the pedestal assembly can demonstrate a clamping pressure in the range of 0.1 kPa to 160 kPa, such as 1 kPa to 155 kPa, 1 kPa to 135 kPa, 1 kPa to 133 kPa, 10 kPa to 130 kPa, 13 kPa to 133 kPa, 20 kPa to 120 kPa, 40 kPa to 100 kPa, or 60 kPa to 80 kPa.

[0032]

[0038] In some embodiments, the pedestal assembly of the present disclosure can demonstrate a clamping pressure greater than 0.1 kPa, such as greater than 1 kPa, greater than 1.3 kPa, greater than 3 kPa, greater than 5 kPa, greater than 10 kPa, or greater than 20 kPa. Regarding the upper limit, the pedestal assembly can demonstrate a clamping pressure less than 70 kPa, such as less than 60 kPa, less than 55 kPa, less than 50 kPa, or less than 45 kPa. Regarding the range, the pedestal assembly can demonstrate a clamping pressure in the range of 0.1 kPa to 70 kPa, such as 1 kPa to 60 kPa, 1.3 kPa to 55 kPa, 5 kPa to 50 kPa, or 10 kPa to 45 kPa.

[0033]

[0039] In some embodiments, the pedestal assembly of the present disclosure can demonstrate a clamping pressure of greater than 70 kPa, such as greater than 100 kPa, greater than 135 kPa, greater than 150 kPa, greater than 200 kPa, or greater than 250 kPa. Regarding the upper limit, the pedestal assembly can demonstrate a clamping pressure of less than 550 kPa, such as less than 500 kPa, less than 450 kPa, less than 400 kPa, or less than 350 kPa. Regarding the range, the pedestal assembly can demonstrate a clamping pressure in the range of 70 kPa to 550 kPa, such as 100 kPa to 500 kPa, 135 kPa to 450 kPa, 150 kPa to 400 kPa, 200 kPa to 400 kPa, or 250 kPa to 350 kPa.

[0034]

[0040] In addition, it has been discovered that certain compositions and processing parameters result in property gradients across the thickness of the pedestal base plate and / or the length of the pedestal shaft. Advantageously, it has been discovered that these gradients better distribute the thermal and mechanical stresses present in high-temperature deposition operations (which can eliminate stress concentration sites). Importantly, these gradients are achieved without the need for individual layers.

[0035]

[0041] The pedestal assembly of the present disclosure can, unexpectedly, achieve the aforementioned clamping pressure under more severe operating conditions, such as temperature, pressure, and / or voltage (compared to conventional pedestal assemblies). In some embodiments, the pedestal can achieve the aforementioned clamping pressure at a temperature greater than 400 °C, such as greater than 500 °C, greater than 600 °C, greater than 700 °C, or greater than 800 °C and / or at a voltage greater than 300 V, such as greater than 400 V, greater than 450 V, greater than 500 V, greater than 550 V, greater than 600 V, or greater than 650 V. In contrast, conventional aluminum nitride pedestals have been found to have highly ineffective clamping under severe operating conditions, and in most cases, conventional aluminum nitride decomposes under these conditions and cannot provide a limited (if any) clamping ability.

[0036] Shaft

[0042] The present disclosure also relates to a shaft. The shaft comprises a BeO composition, such as the aforementioned first BeO composition. By the composition and optional processing thereof, the shaft demonstrates excellent performance characteristics and the microstructure disclosed herein. In particular, the shaft has an average grain boundary or amorphous granular structure greater than 0.1 micron, as described herein. In some cases, the shaft has an advantageous property gradient over the length of the shaft (see below).

[0037]

[0043] The first BeO composition comprises BeO as a main component. BeO may be present in an amount in the range of 50 wt% to 99.9 wt%, such as 75 wt% to 99.9 wt%, 85 wt% to 99.7 wt%, 90 wt% to 99.7 wt%, or 92 wt% to 99.5 wt%. With respect to the lower limit, the first BeO composition may comprise more than 50 wt% BeO, such as more than 75 wt%, more than 85 wt%, more than 90 wt%, more than 92 wt%, more than 95 wt%, more than 98 wt%, or more than 99 wt% BeO. With respect to the upper limit, the first BeO composition may comprise less than 99.9 wt% BeO, such as less than 99.8 wt%, less than 99.7 wt%, less than 99.6 wt%, less than 99.5 wt%, or less than 99.0 wt% BeO.

[0038]

[0044] In some embodiments, the first BeO composition, e.g., the BeO composition of the shaft, contains fluoride ions and / or fluorine in an amount of 1 ppb to 1000 ppm, e.g., 10 ppb to 800 ppm, 100 ppb to 500 ppm, 500 ppb to 500 ppm, 1 ppm to 300 ppm, 25 ppm to 250 ppm, 25 ppm to 200 ppm, 50 ppm to 150 ppm, or 75 ppm to 125 ppm of fluoride ions and / or fluorine. With respect to the lower limit, the first BeO composition may contain more than 1 ppb of fluoride ions and / or fluorine, e.g., more than 10 ppb, more than 100 ppb, more than 500 ppb, more than 1 ppm, more than 2 ppm, more than 50 ppm, or more than 75 ppm of fluoride ions and / or fluorine. With respect to the upper limit, the first BeO composition may contain less than 1000 ppm of fluoride ions and / or fluorine, e.g., less than 800 ppm, less than 500 ppm, less than 300 ppm, less than 250 ppm, less than 200 ppm, less than 150 ppm, or less than 125 ppm of fluoride ions and / or fluorine. In some embodiments, the fluoride / fluoride ion concentration is achieved by treating the first BeO composition, e.g., by performing a separation operation to reach a desired fluorine / fluoride ion concentration. In some cases, the desired fluorine / fluoride ion concentration does not occur naturally and such a separation operation is required. Further, it has been discovered that the disclosed amounts of fluorine / fluoride ions in the BeO composition surprisingly provide unexpected benefits. The fluorine / fluoride ions (optionally in the disclosed amounts) are believed to contribute to / lead to a microstructure that is effective in interfering with phonon wave functions, phonon transport, and / or transmission (through scattering).

[0039]

[0045] In some embodiments, the first BeO composition contains more fluoride ions and / or fluorine than the second BeO composition. The inventors have surprisingly discovered that the difference in fluoride ion and / or fluorine content from the base plate to the shaft is important, at least for the phonon scattering properties described above. In some embodiments, the first BeO composition contains at least 10%, such as at least 20%, at least 30%, at least 50%, at least 75%, or at least 100% more fluoride ions and / or fluorine than the second BeO composition.

[0040]

[0046] In some cases, the first BeO composition further contains magnesium oxide. For example, the first BeO composition may contain magnesium oxide from 1 ppb to 50 wt% ppm, such as from 100 ppm to 25 wt%, from 500 ppm to 10 wt%, from 0.1 wt% to 10 wt%, from 0.5 wt% to 8 wt%, from 0.5 wt% to 5 wt%, from 0.7 wt% to 4 wt%, or from 0.5 wt% to 3.5 wt%. With respect to the lower limit, the first BeO composition may contain more than 1 ppb of magnesium oxide, such as more than 10 ppb, more than 100 ppm, more than 500 ppm, more than 0.1 wt%, more than 0.5 wt%, more than 0.7 wt%, or more than 1 wt%. With respect to the upper limit, the first BeO composition may contain less than 50 wt% of magnesium oxide, such as less than 25 wt%, less than 10 wt%, less than 8 wt%, less than 5 wt%, less than 4 wt%, or less than 3.5 wt%.

[0041]

[0047] In some specific embodiments, the first BeO composition contains silicon dioxide. For example, the first BeO composition may contain from 1 ppb to 50 wt% ppm of silicon dioxide, such as from 100 ppm to 25 wt%, from 500 ppm to 10 wt%, from 0.1 wt% to 10 wt%, from 0.5 wt% to 8 wt%, from 0.5 wt% to 5 wt%, from 0.7 wt% to 4 wt%, or from 0.5 wt% to 3.5 wt% of silicon dioxide. Regarding the lower limit, the first BeO composition may contain more than 1 ppb of silicon dioxide, such as more than 10 ppb, more than 100 ppm, more than 500 ppm, more than 0.1 wt%, more than 0.5 wt%, more than 0.7 wt%, or more than 1 wt% of silicon dioxide. Regarding the upper limit, the first BeO composition may contain less than 50 wt% of silicon dioxide, such as less than 25 wt%, less than 10 wt%, less than 8 wt%, less than 5 wt%, less than 4 wt%, or less than 3.5 wt% of silicon dioxide.

[0042]

[0048] The first BeO composition may contain magnesium trisilicate. For example, the first BeO composition may contain from 1 ppb to 5 wt% of magnesium trisilicate, such as from 1 ppm to 2 wt%, from 100 ppm to 2 wt%, from 500 ppm to 1.5 wt%, from 1000 ppm to 1 wt%, from 2000 ppm to 8000 ppm, from 3000 ppm to 7000 ppm, or from 4000 ppm to 6000 ppm of magnesium trisilicate. Regarding the lower limit, the first BeO composition may contain more than 1 ppb of magnesium trisilicate, such as more than 1 ppm, more than 100 ppm, more than 500 ppm, more than 1000 ppm, more than 2000 ppm, more than 3000 ppm, or more than 4000 ppm of magnesium trisilicate. Regarding the upper limit, the first BeO composition may contain less than 5 wt% of magnesium trisilicate, such as less than 2 wt%, less than 1.5 wt%, less than 1 wt%, less than 8000 ppm, less than 7000 ppm, or less than 6000 ppm of magnesium trisilicate.

[0043]

[0049] In some cases, the first BeO composition further contains alumina. For example, the first BeO composition may contain from 1 ppb to 50 wt% ppm of alumina, such as from 100 ppm to 25 wt%, from 500 ppm to 10 wt%, from 0.1 wt% to 10 wt%, from 0.5 wt% to 8 wt%, from 0.5 wt% to 5 wt%, from 0.7 wt% to 4 wt%, or from 0.5 wt% to 3.5 wt% of alumina. Regarding the lower limit, the first BeO composition may contain more than 1 ppb of alumina, such as more than 10 ppb, more than 100 ppm, more than 500 ppm, more than 0.1 wt%, more than 0.5 wt%, more than 0.7 wt%, or more than 1 wt% of alumina. Upper limit Regarding the upper limit, the first BeO composition may contain less than 50 wt% of alumina, such as less than 25 wt%, less than 10 wt%, less than 8 wt%, less than 5 wt%, less than 4 wt%, or less than 3.5 wt% of alumina.

[0044]

[0050] In some cases, the first BeO composition further contains sulfite. For example, the first BeO composition may contain from 1 ppb to 10000 ppm of sulfite, such as from 1 ppm to 5000 ppm, from 1 ppm to 2000 ppm, from 10 ppm to 1500 ppm, from 10 ppm to 1000 ppm, from 10 ppm to 500 ppm, from 25 ppm to 200 ppm, or from 50 ppm to 150 ppm of sulfite. Regarding the lower limit, the first BeO composition may contain more than 1 ppb of sulfite, such as more than 1 ppm, more than 10 ppm, more than 25 ppm, or more than 50 ppm of sulfite. Regarding the upper limit, the first BeO composition may contain less than 10000 ppm of sulfite, such as less than 5000 ppm, less than 2000 ppm, less than 1500 ppm, less than 1000 ppm, less than 500 ppm, less than 300 ppm, less than 200 ppm, or less than 150 ppm of sulfite.

[0045]

[0051] In some cases, the first BeO composition includes a small amount of non-BeO ceramics, such as oxide ceramics. For example, the first beryllium oxide composition may include less than 75 wt% non-BeO ceramics, such as less than 50 wt%, less than 25 wt%, less than 10 wt%, less than 5 wt%, or less than 1 wt% non-BeO ceramics. Regarding the range, the first BeO composition may include 1 wt% to 75 wt% non-BeO ceramics, such as 5 wt% to 50 wt%, 5 wt% to 25 wt%, or 1 to 10 wt% non-BeO ceramics.

[0046]

[0052] The first BeO composition may further include other components such as boron, barium, sulfur, or lithium, or combinations thereof (including oxides, alloys, composites, or allotropes, or combinations thereof). The first BeO composition may include these components in an amount in the range of 1 ppb to 1 wt% ppm, such as 10 ppb to 0.5 wt%, 10 ppb to 1000 ppm, 10 ppb to 900 ppm, 50 ppb to 800 ppm, 500 ppb to 1000 ppm, 1 ppm to 600 ppm, 50 ppm to 500 ppm, 50 ppm to 250 ppm, or 50 ppm to 150 ppm. Regarding the lower limit, the first BeO composition may include more than 1 ppb, such as more than 10 ppm, more than 50 ppb, more than 100 ppb, more than 500 ppb, more than 1 ppm, more than 50 ppm, more than 100 ppm, or more than 200 ppm of these components. Regarding the upper limit, the first BeO composition may include less than 1 wt%, such as less than 0.5 wt%, less than 1000 ppm, less than 900 ppm, less than 800 ppm, less than 700 ppm, less than 600 ppm, less than 500 ppm, less than 250 ppm, or less than 150 ppm of these components.

[0047]

[0053] In some embodiments, the first BeO composition comprises less than 75 wt%, such as less than 50 wt%, less than 25 wt%, less than 10 wt%, less than 5 wt%, less than 3 wt%, or less than 1 wt% of a non-BeO ceramic, such as aluminum nitride. With respect to ranges, the first BeO composition may comprise from 0.01 wt% to 75 wt%, such as from 0.05 wt% to 50 wt%, from 0.05 wt% to 25 wt%, or from 0.1 to 10 wt% of a non-BeO ceramic.

[0048]

[0054] Other components, such as aluminum (different from the aforementioned alumina), lanthanum, magnesium (different from the aforementioned magnesium oxide or magnesium trisilicate), silicon (different from the aforementioned silicon dioxide and magnesium trisilicate), or yttria or combinations thereof (including oxides, alloys, composites, or allotropes, or combinations thereof) may also be present. These above ranges and limits are applicable to these additional components.

[0049] The second phase

[0055] In some cases, the shaft and / or the base plate comprise a primary phase (the first phase) and a secondary phase (the second phase). The primary phase comprises material particles and the secondary phase comprises a material that forms grain boundaries, such as the material between the particles. The compositions of the primary and secondary phases may differ from each other. The composition of each secondary phase in the shaft and the base plate can affect their performance characteristics, such as thermal conductivity, (theoretical) density, particularly the ability to scatter phonons. Generally, the secondary phase is a relatively small portion of the overall composition of the shaft and / or the base plate. In some cases, the shaft contains, for example, at least 5%, at least 10%, at least 25%, or at least 50% more secondary phase than the base plate, contributing to the improved performance of the assembly.

[0050]

[0056] In some embodiments, the shaft comprises a second phase of from 0.001 wt% to 50 wt%, such as from 0.01 wt% to 25 wt%, from 0.01 wt% to 10 wt%, from 0.05 wt% to 10 wt%, from 0.1 wt% to 10 wt%, from 0.1 wt% to 5 wt%, from 0.5 wt% to 5 wt%, or from 0.5 wt% to 3 wt%. With respect to the upper limit, the shaft may comprise a second phase of less than 50 wt%, such as less than 25 wt%, less than 10 wt%, less than 5 wt%, less than 3 wt% or less than 2 wt%. With respect to the lower limit, the shaft may comprise a second phase of more than 0.001 wt%, such as more than 0.01 wt%, more than 0.05 wt%, more than 0.1 wt%, more than 0.5 wt%, or more than 1 wt%. The weight percentage is based on the total weight of the shaft.

[0051]

[0057] In some embodiments, the base plate comprises a second phase of from 0.05 wt% to 10 wt%, such as from 0.05 wt% to 5 wt%, from 0.1 wt% to 5 wt%, from 0.1 wt% to 3 wt%, or from 0.1 wt% to 1 wt%. With respect to the upper limit, the base plate may comprise a second phase of less than 10 wt%, such as less than 5 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt%. With respect to the lower limit, the base plate may comprise a second phase of more than 0.05 wt%, such as more than 0.1 wt%, more than 0.2 wt%, more than 0.5 wt%, more than 0.7 wt%, or more than 1 wt%. The weight percentage is based on the total weight of the base plate.

[0052]

[0058] In some cases, the second phase may contain a non-BeO component. For example, the second phase of the first BeO composition constituting the shaft may contain magnesia (MgO), silica (SiO2), alumina, yttria, titania, lithia, lanthana, or magnesium trisilicate, or a mixture thereof. The first BeO composition (and the shaft made therefrom) contains a non-BeO component, and each non-BeO component may be present in an amount in the range of 1 ppb to 500 ppm, for example, 500 ppb to 500 ppm, 1 ppm to 300 ppm, 1 ppm to 200 ppm, 10 ppm to 200 ppm, 50 ppm to 150 ppm, or 75 ppm to 125 ppm. Regarding the upper limit, the first BeO composition may contain a non-BeO component, each present in an amount less than 500 ppm, for example, less than 300 ppm, less than 200 ppm, less than 150 ppm, or less than 125 ppm. Regarding the lower limit, the first BeO composition may contain a non-BeO component, each present in an amount greater than 1 ppb, for example, greater than 500 ppb, greater than 1 ppm, greater than 10 ppm, greater than 25 ppm, greater than 50 ppm, greater than 75 ppm, or greater than 100 ppm. These weight percentages are based on the total weight of the first BeO composition, for example, the total weight of the shaft.

[0053]

[0059] In some specific embodiments, the first BeO composition contains magnesium oxide of the second phase in the range of 1 ppb to 10000 ppm, for example, 100 ppm to 9000 ppm, 2000 ppm to 10000 ppm, 5000 ppm to 10000 ppm, 5000 ppm to 9000 ppm, 6000 ppm to 9000 ppm, or 7000 ppm to 8000 ppm. Regarding the lower limit, the first BeO composition contains more than 1 ppb, for example, 10 pp The first beryllium oxide composition may include magnesium oxide of the second phase at 100 ppb or more, 1 ppm or more, 50 ppm or more, 100 ppm or more, 200 ppm or more, 1000 ppm or more, 2000 ppm or more, 3000 ppm or more, 4000 ppm or more, 5000 ppm or more, 6000 ppm or more, or 7000 ppm or more. Regarding the upper limit, the first BeO composition may include magnesium oxide of the second phase at less than 10,000 ppm, for example, less than 9000 ppm, less than 8000 ppm, less than 7000 ppm, less than 6000 ppm, less than 5000 ppm, or less than 4000 ppm.

[0054]

[0060] In some specific embodiments, the first BeO composition includes silicon dioxide of the second phase at 1 ppb to 5000 ppm, for example, 100 ppb to 1000 ppm, 100 ppb to 500 ppm, 1 ppm to 500 ppm, 1 ppm to 100 ppm, 5 ppm to 50 ppm, 1 ppm to 20 ppm, or 2 ppm to 10 ppm. Regarding the lower limit, the first BeO composition includes silicon dioxide of the second phase at more than 1 ppb, for example, more than 10 ppb, more than 100 ppb, more than 200 ppb, more than 500 ppb, more than 1 ppm, more than 2 ppm, more than 5 ppm, or more than 7 ppm. Regarding the upper limit, the first BeO composition includes silicon dioxide of the second phase at less than 5000 ppm, for example, less than 1000 ppm, less than 500 ppm, less than 100 ppm, less than 50 ppm, less than 20 ppm, or less than 10 ppm.

[0055]

[0061] In some specific embodiments, the first BeO composition contains alumina of the second phase in an amount of 1 ppb to 5000 ppm, for example, 100 ppb to 1000 ppm, 100 ppb to 500 ppm, 1 ppm to 500 ppm, 1 ppm to 100 ppm, 5 ppm to 50 ppm, 1 ppm to 20 ppm, or 2 ppm to 10 ppm. Regarding the lower limit, the first BeO composition contains alumina of the second phase in an amount greater than 1 ppb, for example, greater than 10 ppb, greater than 100 ppb, greater than 200 ppb, greater than 500 ppb, greater than 1 ppm, greater than 2 ppm, greater than 5 ppm, or greater than 7 ppm. Regarding the upper limit, the first BeO composition contains alumina of the second phase in an amount less than 5000 ppm, for example, less than 1000 ppm, less than 500 ppm, less than 100 ppm, less than 50 ppm, less than 20 ppm, or less than 10 ppm.

[0056]

[0062] The second phase of the first BeO composition may further contain other components such as carbon, calcium, cerium, iron, hafnium, molybdenum, selenium, titanium, yttrium, or zirconium, or combinations thereof (including oxides, alloys, composites, or allotropes, or combinations thereof). These components may also be present in the first phase (and in the shaft) of the first BeO composition. For example, the first BeO composition may contain these components in an amount in the range of 1 ppb to 5 wt%, for example, 10 ppb to 3 wt%, 100 ppb to 1 wt%, 1 ppm to 1 wt%, 1 ppm to 5000 ppm, 10 ppm to 1000 ppm, 50 ppm to 500 ppm, or 50 ppm to 300 ppm. Regarding the upper limit, these components may be present in an amount less than 5 wt%, for example, less than 3 wt%, less than 1 wt%, less than 5000 ppm, less than 1000 ppm, less than 500 ppm, or less than 300 ppm. Regarding the lower limit, these components may be present in an amount greater than 1 ppb, for example, greater than 10 ppb, greater than 100 ppb, greater than 1 ppm, greater than 10 ppm, or greater than 50 ppm.

[0057]

[0063] It has been discovered that a specific composition of the first BeO composition, optionally in combination with its treatment, results in a specific microstructure that is particularly beneficial for high-temperature performance. Without being bound by theory, magnesium oxide, silicon dioxide, and / or magnesium trisilicate are unexpectedly found to increase the grain boundaries and / or reduce the particle size, creating a thermally restrictive barrier between the particles, for example, it is assumed that a barrier choke is provided between the particles. This improved microstructure is considered to contribute to improved high-temperature performance. In some embodiments, the first BeO composition has an average grain boundary of greater than 0.05 microns, for example, greater than 0.07 microns, greater than 0.09 microns, greater than 0.1 microns, greater than 0.3 microns, greater than 0.5 microns, greater than 0.7 microns, greater than 1.0 microns, greater than 2 microns, greater than 4 microns, greater than 5 microns, greater than 7 microns, and is greater than 10 microns. Regarding the range, the first BeO composition has an average grain boundary in the range of 0.05 microns to 25 microns, for example, 0.05 microns to 15 microns, 0.07 microns to 12 microns, 0.1 microns to 10 microns, 0.5 microns to 10 microns, or 1 micron to 7 microns. In addition to magnesium oxide, silicon dioxide, and / or magnesium trisilicate, it is assumed that other trace components disclosed herein, although not to the same extent, may contribute more beneficially to the improvement.

[0058]

[0064] In some embodiments, the BeO composition has an average particle size of less than 100 microns, such as less than 90 microns, less than 75 microns, less than 60 microns, less than 50 microns, less than 40 microns, less than 35 microns, less than 25 microns, less than 15 microns, less than 10 microns, or less than 5 microns. For ranges, the BeO composition can have an average particle size in the range of 0.1 micron to 100 microns, such as 1 micron to 75 microns, 1 micron to 35 microns, 3 microns to 25 microns, or 5 microns to 15 microns. This smaller particle size beneficially prevents heat transfer, and thus contributes to or enhances high-temperature performance, and it has been found that heat transfer from the plate to the opposite end of the shaft is restricted, with the adjacent ends of the base plate and the shaft remaining at a high temperature while the opposite end of the shaft (the side away from the base plate) remains at a low temperature. It is assumed that a specific particle size also has an advantageous effect on phonon scattering.

[0059]

[0065] In some cases, the shaft includes a "stub" portion (thermal choke portion). The stub portion may, in some cases, be a ring or washer. The stub portion may be used to moderate the shaft temperature. The coefficient of thermal expansion is, similar to the remainder of the shaft, for example, within 25%, within 20%, within 15%, within 10%, within 5%, within 3%, or within 1%.

[0060] Base plate

[0066] The present disclosure also relates to a base plate. The base plate has an upper and a lower portion and includes a BeO composition, such as the aforementioned second BeO composition. By virtue of the composition and its optional processing, the base plate demonstrates the excellent performance characteristics disclosed herein. Specifically, the base plate demonstrates the clamping pressure described herein.

[0061]

[0067] In some embodiments, the second BeO composition, e.g., the BeO composition of the base plate, includes a high purity level of BeO. The purity level of the beryllium oxide composition for the base plate (optionally with its processing to form the base plate) has been found to advantageously contribute to high temperature performance. Also, the BeO utilized in the second BeO composition (or more specifically the first BeO composition) may be processed to achieve a specific purity level. Further, the base plate contains few, if any, individual (laminated) layers, e.g., less than 3, less than 2. In some cases, the base plate has no individual layers, thereby beneficially eliminating the conventional problems of delamination and degradation between layers.

[0062]

[0068] BeO may be present in an amount in the range of 50 wt% to 99.99 wt%, such as 75 wt% to 99.95 wt%, 75 wt% to 99.9 wt%, 85 wt% to 99.7 wt%, 90 wt% to 99.7 wt%, or 92 wt% to 99.5 wt%. With respect to the lower limit, the first BeO composition may contain more than 50 wt%, such as more than 75 wt%, more than 85 wt%, more than 90 wt%, more than 92 wt%, more than 95 wt%, more than 98 wt%, or more than 99 wt% BeO. With respect to the upper limit, the first BeO composition may contain less than 99.99 wt%, such as less than 99.95 wt%, less than 99.90 wt%, less than 99.70 wt%, less than 99.50 wt%, or less than 99.0 wt% BeO. In some embodiments, the BeO concentration of the second BeO composition is higher than the BeO concentration of the first BeO composition, e.g., at least 1%, at least 2%, at least 3%, at least 5%, at least 7% or at least 10% higher. In other words, the base plate BeO composition may have a higher purity than the shaft BeO composition, and the inherent, dielectric, and thermal properties are advantageous because they have been found to be more important for the plate top than for the shaft.

[0063]

[0069] Although not bound by theory, synergistic performance characteristics of the base plate (or shaft), such as improved high-temperature performance, excellent clamping pressure, etc., are at least partially a function of the BeO concentration. It has been discovered that conventional base plates (or shafts), such as those containing non-BeO ceramics, such as aluminum nitride, aluminum oxide, silicon dioxide, or graphite as the main component, cannot achieve such performance. In some embodiments, the second BeO composition contains less than 5 wt%, such as less than 3 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt% of these non-BeO ceramics. For ranges, the second BeO composition may contain 0.01 wt% to 5 wt%, such as 0.05 wt% to 3 wt%, 0.05 wt% to 1 wt%, or 0.1 to 1 wt% of non-BeO ceramics.

[0064]

[0070] The second BeO composition may further contain fluorine / fluoride ions. Also, the fluorine / fluoride ions may be present in the above amounts relative to the first BeO composition. However, as described above, in some cases, the first BeO composition contains more fluoride ions and / or fluorine than the second BeO composition.

[0065]

[0071] In some cases, the second BeO composition may further contain magnesium oxide, silicon dioxide, and / or magnesium trisilicate. The concentrations of these components and their effects on the microstructure (see above) have unexpectedly been found to result in pedestal base plates demonstrating low corrosion loss and high bulk resistivity. Also, low resistivity (optionally combined with other properties) results in improved clamping force (combined with improved high-temperature performance).

[0066]

[0072] In some cases, the second BeO composition further includes magnesium oxide. For example, the second BeO composition may include magnesium oxide in an amount of 1 ppb to 10 wt% ppm, such as 1 ppm to 5 wt%, 10 ppm to 1 wt%, 100 ppm to 1 wt%, 500 ppm to 8000 ppm, 1000 ppm to 8000 ppm, 3000 ppm to 7000 ppm, or 4000 ppm to 6000 ppm. Regarding the lower limit, the second BeO composition may include more than 1 ppb of magnesium oxide, such as more than 10 ppb, more than 1 ppm, more than 10 ppm, more than 100 ppm, more than 500 ppm, more than 1000 ppm, more than 2000 ppm, more than 3000 ppm, or more than 4000 ppm. Regarding the upper limit, the first BeO composition may include less than 10 wt% of magnesium oxide, such as less than 5 wt%, less than 1 wt%, less than 8000 ppm, less than 7000 ppm, or less than 6000 ppm.

[0067]

[0073] In some cases, the second BeO composition further includes silica, alumina, yttria, titania, lithia, lanthanum, or magnesium trisilicate, or a mixture thereof. These components may be present in the amounts described for magnesium oxide in the second BeO composition.

[0068]

[0074] In some cases, the second BeO composition further includes lithia at a lower concentration, such as 1 ppb to 1 wt%, such as 100 ppb to 0.5 wt%, 1 ppm to 0.1 wt%, 100 ppm to 900 ppm, 200 ppm to 800 ppm, 300 ppm to 700 ppm, or 400 ppm to 600 ppm. Regarding the lower limit, the second BeO composition may include more than 1 ppb of lithia, such as more than 100 ppb, more than 1 ppm, more than 100 ppm, more than 200 ppm of lithia. Regarding the upper limit, the first BeO composition may include less than 10 wt% of lithia, such as less than 1 wt%, less than 0.5 wt%, less than 0.1 wt% ppm, less than 900 ppm, less than 800 ppm, less than 700 ppm, or less than 600 ppm.

[0069]

[0075] The second BeO composition may further include other components such as carbon, calcium, cerium, iron, hafnium, molybdenum, selenium, titanium, yttrium, or zirconium, or combinations thereof (including oxides, alloys, composites, or allotropes, or combinations thereof). These components may also be present in the second phase of the second BeO composition (and in the base plate). For example, the second BeO composition may include these components in an amount in the range of 1 ppb to 5 wt%, such as 10 ppb to 3 wt%, 100 ppb to 1 wt%, 1 ppm to 1 wt%, 1 ppm to 5000 ppm, 10 ppm to 1000 ppm, 50 ppm to 500 ppm, or 50 ppm to 300 ppm. With respect to the upper limit, these components may be present in an amount less than 5 wt%, such as less than 3 wt%, less than 1 wt%, less than 5000 ppm, less than 1000 ppm, less than 500 ppm, or less than 300 ppm. With respect to the lower limit, these components may be present in an amount greater than 1 ppb, such as greater than 10 ppb, greater than 100 ppb, greater than 1 ppm, greater than 10 ppm, or greater than 50 ppm.

[0070]

[0076] In some embodiments, the second BeO composition may further include the above-described other components relative to the first BeO composition. The compositional ranges and limits are also applicable to the second BeO composition.

[0071]

[0077] In some embodiments, the first beryllium oxide composition includes more magnesium oxide and / or magnesium trisilicate and / or other components than the second beryllium oxide composition. The benefits regarding the microstructure of these components are described above.

[0072] The second phase

[0078] In some cases, the second phase of the second BeO composition may contain non-BeO components. For example, the second phase of the second BeO composition constituting the base plate may contain magnesia, silica, alumina, yttria, titania, lithia, lanthana, or magnesium trisilicate, or a mixture thereof. The second BeO composition (and the base plate made therefrom) may contain non-BeO components of the second phase, each in an amount in the range of 1 ppb to 500 ppm, for example, 500 ppb to 500 ppm, 1 ppm to 300 ppm, 1 ppm to 200 ppm, 10 ppm to 200 ppm, 50 ppm to 150 ppm, or 75 ppm to 125 ppm. With respect to the upper limit, the first BeO composition may contain non-BeO components of the second phase, each in an amount less than 500 ppm, for example, less than 300 ppm, less than 200 ppm, less than 150 ppm, or less than 125 ppm. With respect to the lower limit, the second BeO composition may contain non-BeO components, each in an amount greater than 1 ppb, for example, greater than 500 ppb, greater than 1 ppm, greater than 10 ppm, greater than 25 ppm, greater than 50 ppm, greater than 75 ppm, or greater than 100 ppm. These weight percentages are based on the total weight of the first BeO composition, for example, the total weight of the shaft.

[0073] Performance

[0079] In addition to the clamping pressure, the base plate has been found to demonstrate a synergistic combination of performance characteristics. For example, the base plate can demonstrate excellent performance in one or more of the following aspects: · Temperature uniformity · Bulk resistivity · Corrosion loss · Dielectric constant

[0080] The numerical values and limiting values of these performance characteristics are described in detail below.

[0074]

[0081] In some embodiments, the base plate has a consistent coefficient of thermal expansion (CTE) from top to bottom. For example, the CTE does not vary from top to bottom. For example, the coefficient of thermal expansion may vary less than 25%, such as less than 20%, less than 15%, less than 10%, less than 7%, less than 5%, less than 3%, or less than 1% from top to bottom.

[0075]

[0082] In one embodiment, a pedestal, such as a base plate, demonstrates a short (if any) cleaning cycle time. During operation, cleaning of the pedestal, wafer substrate, and / or chamber, and cleaning / removal of assembly overspray may be required. Conventionally, pedestal assemblies require a cooling step to reach a temperature suitable for cleaning, such as a step of at least 1 hour to reach 300 °C. And subsequent additional heating steps, such as a step of at least another 1 hour to return to the original temperature. Also, the wafer must withstand these temperature changes. Due to the composition of the pedestal / base plate of the present disclosure, cooling (or subsequent reheating) is not required, cleaning can be performed at the operating temperature, the cleaning cycle time is minimized (if not eliminated), and the wafer may not need to be as stable. In some embodiments, the cleaning cycle time of the pedestal / base plate is less than 2 hours, such as less than 1.5 hours, less than 1 hour, less than 45 minutes, less than 30 minutes, less than 20 minutes, less than 10 minutes, or less than 5 minutes.

[0076]

[0083] In some cases, the present disclosure further relates to a method of cleaning a contaminated pedestal assembly / wafers / chamber. The method includes providing a pedestal assembly and wafers in the chamber (placing the wafers on top of the pedestal assembly), and heating the wafers to an operating temperature of at least 400°C, at least 450°C, at least 500°C, at least 550°C, at least 600°C, at least 650°C, or at least 700°C. Once the manufacturing temperature (if contaminated) is reached, the method includes cooling the wafers to a cooling temperature at a rate of less than 150°C, for example, less than 100°C, less than 50°C, less than 25°C, or less than 10°C (or not cooling at all with respect to BeO), and cleaning the plate at the cooling temperature. In some embodiments, the method further includes reheating the wafers to an operating temperature of at least 400°C, at least 450°C, at least 500°C, at least 550°C, at least 600°C, at least 650°C, or at least 700°C. Importantly, the cleaning cycle time from the cooling step to the reheating step is shorter than conventional methods, for example, less than 2 hours, for example, less than 1.5 hours, less than 1 hour, less than 45 minutes, less than 30 minutes, less than 20 minutes, less than 10 minutes, or less than 5 minutes. Advantageously, due to the composition of the pedestal / base plate of the present disclosure, cooling (or subsequent reheating) is not required or minimized, cleaning can be performed at the operating temperature (or a temperature slightly below it), the cleaning cycle time is minimized (if not eliminated), and the wafers may not need to be as stable.

[0077]

[0084] The base plate of the present disclosure may be larger in size than some conventional base plates, and further demonstrates the excellent performance characteristics described herein. Conventionally, manufacturers have struggled to produce large base plates that demonstrate suitable characteristics. As is known in the art, as the size of the base plate increases, it becomes difficult to manufacture the base plate while maintaining performance. Some reasons include the high CTE of conventional pedestal materials that detrimentally lead to cracking problems, and the size limitations of conventional off-the-shelf equipment. In some embodiments, the minimum lateral dimension of the base plate is at least 100 mm, for example, at least 125 mm, at least 150 mm, at least 175 mm, at least 200 mm, at least 225 mm, at least 250 mm, at least 300 mm, at least 400 mm, at least 500 mm, at least 750 mm, or at least 1000 mm.

[0078]

[0085] In some embodiments, the base plate has flatness with a camber of less than 50 microns, for example, less than 40 microns, less than 30 microns, less than 25 microns, less than 15 microns, less than 10 microns, or less than 5 microns over a distance of 300 mm.

[0079]

[0086] In some cases, the base plate further includes a mesa (standoff). The mesa is used to lift the wafer. In some embodiments, the mesa protrudes upward from the upper surface of the base plate. The mesa may have an average height in the range of 1 micron to 50 microns, for example, 1.5 microns to 40 microns, 2 microns to 30 microns, 2 microns to 20 microns, 2.5 microns to 18 microns, or 5 microns to 15 microns. With respect to the lower limit, the mesa may have an average height greater than 1 micron, for example, greater than 1.5 microns, greater than 2 microns, greater than 2.5 microns, greater than 3 microns, or greater than 5 microns. With respect to the upper limit, the mesa may have an average height less than 50 microns, for example, less than 40 microns, less than 30 microns, less than 20 microns, less than 18 microns, or less than 15 microns.

[0080]

[0087] In some cases, the base plate further includes a heating element enclosed within the base plate. In some examples, the heating element is a coiled or crimped heating element. The combination of BeO composition and / or crimped or coiled heating element unexpectedly provides improved temperature uniformity (see below) compared to conventional base plates using non-BeO ceramics and / or other types of heating elements.

[0081]

[0088] The base plate may further include other hardware, such as an antenna. These features are described in more detail below. In some cases, the antenna and / or heating element includes niobium and / or platinum and / or titanium. The inventors have discovered that niobium and / or platinum and / or titanium, when used with a BeO composition, provide a synergistic effect in the coefficient of thermal expansion, as well as unexpected performance in terms of corrosion resistance and electrical resistance. In some cases, these metals, when used as hardware, have a thermal compatibility factor that synergistically works well with the BeO material. The thermal compatibility factor has been discovered to prevent stress-induced failures caused, for example, by temperature cycling.

[0082] Concept / Performance of Base Plate Gradient

[0089] The present disclosure also relates to base plates designed to have various property gradients from top to bottom. These base plates can be manufactured by forming a precursor using multiple types of powders each having different properties and then heating the precursor to form a base plate having a property gradient. Importantly, the resulting base plate does not include individual layers and provides benefits to the entire layered base plate assembly.

[0083]

[0090] In some embodiments, the base plate is made from two or more grades of raw material BeO powder. In one embodiment, the upper surface includes a first grade, the lower surface includes a second grade, and the intermediate region includes a mixture of the first and second grades. For example, the first grade may be a material with higher purity / higher thermal conductivity / higher (theoretical) density / lower porosity, and the second grade may be a material with lower purity / lower thermal conductivity / lower (theoretical) density / higher porosity. Of course, various other numbers and combinations of raw material BeO powders are conceivable.

[0084]

[0091] The base plate can demonstrate one or more of the following desirable performance gradients. · A thermal conductivity gradient decreasing from top to bottom · A resistivity gradient decreasing from top to bottom · A purity gradient decreasing from top to bottom · A theoretical density gradient decreasing from top to bottom · A dielectric constant gradient increasing from top to bottom

[0092] These performance gradients each have an "upper value" when measured at the top of the plate and a "lower value" when measured at the bottom of the plate. The endpoints of the ranges in this specification may be used as upper and lower limits. For example, a range of 231 - 350 W / mK with an upper limit less than 350 W / mK and a lower limit of 231 W / mK can occur.

[0085]

[0093] Thermal conductivity: In some embodiments, the base plate has an upper thermal conductivity in the range of 125 to 400 W / mK, for example, 231 to 350 W / mK, 250 to 350 W / mK, 265 to 335 W / mK, or 275 to 325 W / mK when measured at room temperature. The base plate may have a lower thermal conductivity in the range of 146 to 218 W / mK, for example, 150 to 215 W / mK, 160 to 205 W / mK, 165 to 200 W / mK, or 170 to 190 W / m-K when measured at room temperature. With respect to the upper limit, the base plate may have a thermal conductivity of less than 400 W / m-K at room temperature, for example, less than 375 W / mK, less than 350 W / mK, less than 300 W / mK, less than 275 W / mK, less than 255 W / mK, or less than 250 W / mK.

[0086]

[0094] The base plate may have an upper thermal conductivity in the range of 25 to 105 W / mK, for example, 35 to 95 W / mK, 45 to 85 W / mK, or 55 to 75 W / mK when measured at 800 °C. The base plate may have a lower thermal conductivity in the range of 1 to 21 W / mK, for example, 3 to 20 W / mK, 5 to 15 W / mK, 7 to 13 W / mK, or 9 to 11 W / mK when measured at 800 °C.

[0087]

[0095] Generally, the lower thermal conductivity is lower than the upper thermal conductivity. The upper thermal conductivity may be at least 6%, for example, at least 10%, at least 20%, at least 35%, at least 50%, at least 100%, or at least 200% higher than the lower thermal conductivity when measured at room temperature or 800 °C, or regardless of the measurement temperature.

[0088]

[0096] Resistivity: In some cases, the upper resistivity is, at room temperature, 1×10 5 ~1×10 16 Ohm m, for example, 1×10 6 ~1×10 16 、1×10 7 ~5×10 15 、1×10 8 ~1×10 15 、or 1×10 9 ~1×10 15It is in the range of ohm·m. The lower resistivity may be lower than the upper resistivity. The lower resistivity is 1×10 5 ~1×10 16 ohm·m, for example, 1×10 5 ~1×10 15 , 1×10 5 ~5×10 14 , 1×10 6 ~1×10 13 , or 1×10 7 ~5×10 12 and may be in the range of ohm·m.

[0089]

[0097] In these cases, the upper resistivity is higher than the lower resistivity. Generally, the lower resistivity is at least 150%, at least 200%, at least 250%, at least 300%, at least 500%, or at least 1000% lower than the upper resistivity.

[0090]

[0098] Purity: The upper purity is in the range of 99.0% - 99.9% in some embodiments, for example, 99.1% - 99.9%, 99.4% - 99.8%. The lower purity may be in the range of 95.0% - 99.5%, for example, 95.5% - 99.5%, 96% - 99%, or 96.5% - 98.5%. Generally, the lower purity is at least 0.2%, at least 0.4%, at least 0.5%, or at least 1.0% lower than the upper purity.

[0091]

[0099] Theoretical density: In some cases, the upper theoretical density may be in the range of 93 - 200, for example, 94 - 100, 95 - 100, 96 - 99.5, or 97 - 99. The lower theoretical density may be in the range of 93 - 100, for example, 94 - 99.5, 95 - 99, or 96 - 98. Generally, the lower theoretical density is lower than the upper theoretical density. The upper theoretical density may be at least 0.1%, for example, at least 0.2%, at least 0.4%, at least 0.5% or at least 1.0% higher than the lower theoretical density.

[0092]

[0100] The theoretical density of the base plate may be equivalent to the theoretical density of the shaft. In some cases, the theoretical density of the shaft is lower than the theoretical density of the base plate, and / or the porosity of the shaft is higher than the porosity of the base plate.

[0093]

[0101] Particle size: In some cases, the upper (maximum) particle size may range from 5 to 60 microns, for example, 10 to 50 microns, 15 to 45 microns, or 20 to 40 microns. The lower (maximum) particle size may range from 10 to 100 microns, for example, 20 to 90 microns, 25 to 85 microns, or 30 to 80 microns. Generally, the lower (maximum) particle size is larger than the upper particle size. The upper particle size may be at least 0.1%, for example, at least 0.2%, at least 0.4%, at least 0.5%, or at least 1.0% smaller than the lower particle size.

[0094]

[0102] Grain boundary: In some cases, the overall grain boundary may range from amorphous to 10 microns, for example, 1 to 9 microns, 2 to 8 microns, or 3 to 7 microns. In some cases, the lower grain boundary is smaller than the upper grain boundary. In other embodiments, the upper grain boundary is smaller than the lower grain boundary.

[0095]

[0103] Specific heat: In some embodiments, the base plate has an upper specific heat in the range of 0.9 to 1.19 J / gK, for example, 0.95 to 1.15 J / gK, or 1.0 to 1.1 J / gK when measured at room temperature. The base plate may have a lower specific heat in the range of 0.9 to 1.19 J / gK, for example, 0.95 to 1.15 J / gK, or 1.0 to 1.1 J / gK when measured at room temperature.

[0096]

[0104] The base plate may have an upper specific heat in the range of 1.8 to 2.06 J / gK, for example, 1.85 to 2.03 J / gK, or 1.87 to 1.97 J / gK when measured at 800 °C. The base plate may have a lower specific heat in the range of 1.8 to 2.03 J / gK, for example, 1.85 to 2.03 J / gK, or 1.87 to 1.97 J / gK when measured at 800 °C.

[0097]

[0105] Generally, the lower specific heat is lower than the upper specific heat. The upper specific heat may be at least 0.5%, for example, at least 1%, at least 2%, at least 5%, at least 10% or at least 20% higher than the lower specific heat when measured at room temperature or 800 °C, or regardless of the measurement temperature.

[0098]

[0106] Thermal diffusivity: In some embodiments, the base plate has an upper thermal diffusivity in the range of 90 to 115 mm 2 / sec, for example, 95 to 110 mm 2 / sec, or 97 to 108 mm 2 / sec when measured at room temperature. The base plate may have a lower thermal diffusivity in the range of 58 to 115 mm 2 / sec, for example, 65 to 105 mm 2 / sec, or 75 to 95 mm 2 / sec when measured at room temperature.

[0099]

[0107] The base plate may have an upper thermal diffusivity in the range of 5 to 21 mm 2 / sec, for example, 7 to 19 mm 2 / sec, 9 to 17 mm 2 / sec, or 10 to 15 mm 2 / sec when measured at 800 °C. The base plate may have a lower thermal diffusivity in the range of 3 to 7.7 mm / sec, for example, 3.5 to 7 mm 2 / sec, or 4 to 6 mm 2 / sec when measured at 800 °C. 2 / sec when measured at 800 °C.

[0100]

[0108] Generally, the lower thermal diffusivity is lower than the upper thermal diffusivity. The upper thermal diffusivity may be at least 0.5%, for example, at least 1%, at least 2%, at least 5%, at least 10%, or at least 20% higher than the lower thermal diffusivity when measured at room temperature or 800 °C, or regardless of the measurement temperature.

[0101]

[0109] Permeability: In some embodiments, the base plate has an upper permeability in the range of 22.0 - 30.02 S 0.5 W / K / km 2 , for example, 24.0 - 30.02 S 0.5 W / K / km 2 , 25.0 - 29.0 S 0.5 W / K / km 2 , or 26.0 - 28.0 S 0.5 W / K / km 2 when measured at room temperature. The base plate may have a lower thermal permeability in the range of 1.0 - 25.0 S 0.5 W / K / km 2 , for example, 3.0 - 24.0 S 0.5 W / K / km 2 , or 5.0 - 23.0 S 0.5 W / K / km 2 . In some embodiments, the base plate has an (upper) permeability greater than 22.0 S 0.5 W / K / km 2 , for example, greater than 23.0 S 0.5 W / K / km 2 , greater than 24.0 S 0.5 W / K / km 2 , greater than 25.0 S 0.5 W / K / km 2 , greater than 27.0 S 0.5 W / K / km 2 , greater than 28.0 S 0.5 W / K / km 2 , or greater than 30.0 S 0.5 W / K / km 2 .

[0102]

[0110] The base plate has an upper permeability in the range of 11.0 - 16.4 S when measured at 800 °C 0.5W / K / km 2 e.g., 12.0 to 15.0 S 0.5 W / K / km 2 12.5 to 14.5 S 0.5 W / K / km 2 or 13.0 to 14.0 S 0.5 W / K / km 2 and may have an upper penetration rate in the range of. The base plate, when measured at 800 °C, is 0.1 to 12.0 S 0.5 W / K / km 2 e.g., 0.5 to 11.0 S 0.5 W / K / km 2 or 1.0 to 10.0 S 0.5 W / K / km 2 and may have a lower heat penetration rate in the range of. In some embodiments, the base plate is 14.0 S 0.5 W / K / km 2 over, e.g., 15.0 S 0.5 W / K / km 2 over, 16.0 S 0.5 W / K / km 2 over, 17.0 S 0.5 W / K / km 2 over, 18.0 S 0.5 W / K / km 2 over, 19.0 S 0.5 W / K / km 2 over, or 20.0 S 0.5 W / K / km 2 over and has an (upper) penetration rate. The improvement in the penetration rate can also be shown at other temperatures as shown in the examples, for example.

[0103]

[0111] Generally, the lower penetration rate is lower than the upper penetration rate. The upper penetration rate, when measured at room temperature or 800 °C, or regardless of the measurement temperature, may be at least 0.5%, for example, at least 1%, at least 2%, at least 5%, at least 10%, or at least 20% higher than the lower penetration rate.

[0104]

[0112] Average CTE: In some embodiments, the base plate has an upper average CTE in the range of 7.0 to 9.5, such as 7.2 to 9.3, 7.5 to 9.0, or 7.7 to 8.8. The base plate may have a lower average CTE in the range of 7.0 to 9.5, such as 7.2 to 9.3, 7.5 to 9.0, or 7.7 to 8.8. In some cases, the lower average CTE is lower than the upper average CTE. In other cases, the lower average CTE is higher than the upper average CTE. The difference may be at least 0.5%, such as at least 1%, at least 2%, at least 5%, at least 10%, or at least 20% when measured at room temperature or 800 °C, or regardless of the measurement temperature.

[0105]

[0113] In some embodiments, the upper dielectric constant is in the range of 1 to 20, such as ~15, 3 to 12, or 5 to 9. The lower dielectric constant may be the same as the upper dielectric constant. In some cases, the lower dielectric constant may be higher than the upper dielectric constant. In other cases, the upper dielectric constant may be higher than the lower dielectric constant. The upper dielectric constant may be higher than the lower dielectric constant.

[0106]

[0114] The base plate having a desired performance gradient may be formed for the BeO composition described herein and, in some cases, is modified in the composition parameters to achieve the gradient. Also, the base plate can demonstrate other performance characteristics, such as the clamping pressure, corrosion loss, temperature uniformity, etc. disclosed herein.

[0107] Shaft Gradient Concept / Performance

[0115] In some embodiments, the shaft has an upper thermal conductivity in the range of 146 W / mK to 218 W / mK, such as 150 W / mK to 215 W / mK, 160 W / mK to 205 W / mK, 165 W / mK to 200 W / mK, or 170 W / mK to 190 W / mK, when measured at room temperature. The shaft may have a lower thermal conductivity in the range of 1 W / mK to 218 W / mK, such as 50 W / mK to 218 W / mK, 100 W / mK to 218 W / mK, 146 W / mK to 218 W / mK, 150 W / mK to 215 W / mK, 160 W / mK to 205 W / mK, 165 W / mK to 200 W / mK, or 170 W / mK to 190 W / mK, when measured at room temperature.

[0108]

[0116] The shaft may have an upper thermal conductivity in the range of 1 to 21, such as 3 to 20, 5 to 15, 7 to 13, or 9 to 11, when measured at 800 °C. The shaft may have a lower thermal conductivity in the range of 1 to 21, such as 3 to 20, 5 to 15, 7 to 13, or 9 to 11, when measured at 800 °C.

[0109]

[0117] Generally, the lower thermal conductivity is lower than the upper thermal conductivity. The upper thermal conductivity may be at least 6%, such as at least 10%, at least 20%, at least 35%, at least 50%, at least 100%, or at least 200% higher than the lower thermal conductivity when measured at room temperature or 800 °C, or regardless of the measurement temperature. In some cases, the gradient may be non-linear, such as a stepwise function or a ceiling function. In other cases, the gradient may be linear.

[0110] General performance

[0118] The base plate and the shaft demonstrate excellent performance values even without generally considering the gradient. In some cases, the performance regions and limit values of the base plate may be the same as the above-mentioned "upper values" and / or "lower values" overall or as a whole. These are not repeated for simplicity. Additional performance regions and limit values are also provided.

[0111]

[0119] Thermal diffusivity: In some embodiments, the base plate has an (upper) thermal diffusivity in the range of 75 to 115 mm 2 / sec, for example, 90 to 115 mm 2 / sec, 95 to 110 mm 2 / sec, or 97 to 108 mm 2 / sec when measured at room temperature. The base plate may have a lower thermal diffusivity in the range of 58 to 115 mm 2 / sec, for example, 65 to 105 mm 2 / sec, or 75 to 95 mm 2 / sec. In some embodiments, the base plate has an (upper) thermal diffusivity greater than 75 mm 2 / sec, for example, greater than 80 mm 2 / sec, greater than 85 mm 2 / sec, greater than 90 mm 2 / sec, greater than 95 mm 2 / sec, greater than 100 mm 2 / sec, or greater than 110 mm 2 / sec.

[0112]

[0120] The base plate may have an upper thermal diffusivity in the range of 5 to 21 mm 2 / sec, for example, 7 to 19 mm 2 / sec, 9 to 17 mm 2 / sec, or 10 to 15 mm 2 / sec when measured at 800 °C. The base plate may have a lower thermal diffusivity in the range of 3 to 7.7 mm 2 / sec, for example, 3.5 to 7 mm 2 / sec, or 4 to 6 mm 2 / sec. In some embodiments, the base plate has an upper thermal diffusivity greater than 5 mm 2 / sec, for example, greater than 10 mm 2 / sec, greater than 12 mm 2 / sec, greater than 14 mm 2 / sec, greater than 15 mm 2 / sec, or greater than 20 mm 2It has a (upper) thermal diffusivity exceeding / sec. The improvement in thermal diffusivity can be shown at other temperatures as well, for example, as shown in the examples.

[0113]

[0121] Specific heat: In some embodiments, the base plate has an upper specific heat in the range of 0.7 to 1.19 J / gK, for example, 0.9 to 1.19 J / gK, 0.95 to 1.15 J / gK, or 1.0 to 1.1 J / gK when measured at room temperature. The base plate may have a lower specific heat in the range of 0.9 to 1.19 J / gK, for example, 0.95 to 1.15 J / gK, or 1.0 to 1.1 J / gK when measured at room temperature. In some embodiments, the base plate has a (upper) specific heat exceeding 0.7 J / gK, for example, exceeding 0.8 J / gK, exceeding 0.9 J / gK, exceeding 0.95 J / gK, or exceeding 1.0 J / gK.

[0114]

[0122] The base plate may have an upper specific heat in the range of 1.0 to 2.06 J / gK, for example, 1.8 to 2.06 J / gK, 1.85 to 2.03 J / gK, or 1.87 to 1.97 J / gK when measured at 800 °C. The base plate may have a lower specific heat in the range of 1.8 to 2.03 J / gK, for example, 1.85 to 2.03 J / gK, or 1.87 to 1.97 J / gK when measured at 800 °C. In some embodiments, the base plate has a (upper) specific heat exceeding 1.0 J / gK, for example, exceeding 1.5 J / gK, exceeding 1.7 J / gK, exceeding 1.8 J / gK, or exceeding 1.85 J / gK. The improvement in specific heat can also be shown at other temperatures as well, for example, as shown in the examples.

[0115]

[0123] Thermal conductivity: In one embodiment, the second beryllium oxide composition (and the base plate) generally has a thermal conductivity of less than 400 W / m-K at room temperature, for example, less than 375 W / m-K, less than 350 W / m-K, less than 300 W / m-K, less than 275 W / m-K, less than 255 W / m-K, or less than 250 W / m-K. In terms of a range, the second beryllium oxide composition has a thermal conductivity in the range of 125 W / m-K to 400 W / m-K, for example, 145 W / m-K to 350 W / m-K, 175 W / m-K to 325 W / m-K, or 200 W / m-K to 300 W / m-K. In some embodiments, the base plate has a (top) thermal conductivity of greater than 125 W / m-K, for example, greater than 150 W / m-K, greater than 175 W / m-K, greater than 200 W / m-K, greater than 250 W / m-K, or greater than 255 W / m-K. The thermal conductivity can be measured at the top of the base plate.

[0116]

[0124] In one embodiment, the second beryllium oxide composition (and the base plate) generally has a thermal conductivity of less than 150 W / m-K at 800 °C, for example, less than 105 W / m-K, less than 95 W / m-K, less than 85 W / m-K, or less than 75 W / m-K. In terms of a range, the second beryllium oxide composition has a thermal conductivity in the range of 25 to 105 W / mK, for example, 35 to 95 W / mK, 45 to 85 W / mK, or 55 to 75 W / mK when measured at 800 °C. The thermal conductivity can be measured at the top of the base plate. In some embodiments, the base plate has a (top) thermal conductivity of greater than 25 W / m-K, for example, greater than 30 W / m-K, greater than 35 W / m-K, greater than 40 W / m-K, greater than 42 W / m-K, or greater than 45 W / m-K. The improvement in thermal conductivity can also be shown at other temperatures, for example, as shown in the examples. The thermal conductivity can be measured at the top of the base plate.

[0117]

[0125] Shaft thermal conductivity: In some embodiments, the first beryllium oxide composition (and shaft) generally has a thermal conductivity of less than 300 W / m-K at room temperature, such as less than 275 W / m-K, less than 250 W / m-K, less than 225 W / m-K, less than 220 W / m-K, less than 218 W / m-K, or less than 210 W / m-K. For ranges, the first beryllium oxide composition has a thermal conductivity in the range of 100 W / m-K to 300 W / m-K, such as 125 W / m-K to 275 W / m-K, 125 W / m-K to 250 W / m-K, or 140 W / m-K to 220 W / m-K. In some embodiments, the shaft has an (upper) thermal conductivity greater than 125 W / m-K, such as greater than 150 W / m-K, greater than 175 W / m-K, greater than 200 W / m-K, greater than 250 W / m-K, or greater than 255 W / m-K. The thermal conductivity can be measured at the top of the base plate. The thermal conductivity can be measured at the top of the shaft.

[0118]

[0126] In some cases, the first beryllium oxide composition (and base plate) generally has a thermal conductivity of less than 25 W / m-K at 800 °C, such as less than 23 W / m-K, less than 21 W / m-K, less than 20 W / m-K, less than 15 W / m-K, less than 10 W / m-K, or less than 5 W / m-K. For ranges, the second beryllium oxide composition has a thermal conductivity in the range of 1 to 5 W / mK when measured at 800 °C, such as 2 to 23 W / mK, 4 to 21 W / mK, or 5 to 20 W / mK. In some embodiments, the shaft has an (upper) thermal conductivity greater than 25 W / m-K, such as greater than 30 W / m-K, greater than 35 W / m-K, greater than 40 W / m-K, greater than 42 W / m-K, or greater than 45 W / m-K. The improvement in thermal conductivity can be shown at other temperatures as well, for example, as shown in the examples. The thermal conductivity can be measured at the top of the base plate.

[0119]

[0127] Theoretical density of the shaft: In some embodiments, the first BeO composition (and shaft) generally has a theoretical density in the range of 90 to 100, such as 92 to 100, 93 to 99, 95 to 99, or 97 to 99. With respect to the lower limit, the shaft has a theoretical density greater than 90, such as greater than 92, greater than 93, greater than 95, or greater than 97. With respect to the upper limit, the shaft has a theoretical density less than 100, such as less than 99.5, less than 99, less than 98.7, or less than 98. It is assumed that the desired theoretical density and porosity may be derived from the microstructural features obtained by the first BeO composition, such as grain boundaries and grain size.

[0120]

[0128] In some embodiments, the base plate has a resistance greater than 1×10 4 ohm m at 800 °C, such as greater than 5×10 4 ohm m, greater than 1×10 5 ohm m, greater than 5×10 5 ohm m, greater than 1×10 6 ohm m, greater than 5×10 6 ohm m, greater than 1×10 7 ohm m, greater than 5×10 7 ohm m, greater than 1×10 8 ohm m, greater than 5×10 8 ohm m, greater than 1×10 9 ohm m, or greater than 1×10 10 ohm m, demonstrating a bulk resistivity. This resistivity advantageously results in at least partially improved clamping performance.

[0121]

[0129] The inventors have discovered that it may be beneficial for the shaft to have a lower density / higher porosity than the base plate. Also, the microstructure of each BeO composition is adjusted accordingly as disclosed herein. Such a configuration is surprisingly considered to avoid the heat sink effect (creation of cold spots) and / or deformation (melting) of the original plate / shaft seal.

[0122]

[0130] The theoretical density of the pedestal component is an important feature. In some cases, the theoretical density (and / or porosity) affects or contributes to the thermal conductivity.

[0131] Porosity has been found to beneficially suppress the spread of microdamage. In some embodiments, the base plate and / or the shaft have a porosity in the range of 0.1% to 10%, such as 0.5% to 8%, 1% to 7%, 1% to 5%, or 2% to 4%. Regarding the upper limit, the base plate and / or the shaft may have a porosity of less than 10%, such as less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, or less than 1%. Regarding the lower limit, the base plate and / or the shaft may have a porosity of more than 1%, such as more than 2%, more than 3%, more than 4%, more than 5%, more than 6%, more than 7%, more than 8%, or more than 9%.

[0123]

[0132] The second BeO composition advantageously contributes to a uniform temperature performance across the entire base plate, especially at high temperatures. Such temperature uniformity has not been achieved using conventional non-BeO ceramics. In some embodiments, the base plate demonstrates a temperature variation of less than ±3%, such as less than ±2.5%, less than ±2%, less than ±1%, or less than ±0.5% when heated to a temperature above 700°C, such as above 750°C, above 800°C, or 850°C. Temperature can be measured via, for example, a thermocouple, IR, or TCR device on the upper surface of the plate, as is known in the art.

[0124]

[0133] In some cases, the base plate can demonstrate a corrosion loss of less than 0.016 wt%, such as less than 0.015 wt%, less than 0.013 wt%, less than 0.012 wt%, less than 0.010 wt%, less than 0.008 wt%, or less than 0.005 wt% after 200 cycles. Corrosion loss can be examined by measuring the weight of the sample before and after circulating the sample according to a test protocol (e.g., 200 cycles (5.5 hours) in NF3 at 400°C and 4 cycles (12 hours) in ClF at 300°C).

[0125]

[0134] ​The base plate can, in some cases, demonstrate a change in decomposition of less than 1 wt%, for example, less than 0.1 wt% or less than 0.005 wt% at temperatures above 1600 °C. Decomposition can be defined as decomposition (in some cases, dissociation) into its precursor components, for example, a chemical change. The base plate of the present disclosure has advantageously been found to have an improved softening point and decomposition point. In some embodiments, the base plate has a softening point above 1600 °C, for example, above 1700 °C, above 1750 °C, above 1800 °C, above 1850 °C, above 1900 °C, or above 2000 °C. In some embodiments, the base plate has a melting point (in nitrogen gas) above 2200 °C, for example, above 2325 °C, above 2350 °C, above 2400 °C, above 2450 °C. Different from conventional base plates, the base plate of the present disclosure can apply the aforementioned clamping pressure at these temperatures. Conventional base plates, for example, aluminum nitride base plates, decompose at temperatures below 1600 °C and melt at temperatures below 2200 °C.

[0126]

[0135] In some embodiments, the base plate has a dielectric constant of less than 20, for example, less than 17, less than 15, less than 12, less than 10, less than 8, or less than 7.

[0136] In some examples, the base plate has a surface hardness of at least 50 Rockwell, for example, at least 50 Rockwell, at least 52 Rockwell, at least 55 Rockwell, at least 57 Rockwell, at least 60 Rockwell, at least 65 Rockwell, or at least 70 Rockwell when measured on a 45N scale.

[0127]

[0137] In some embodiments, the base plate has a coefficient of thermal expansion in the range of 5 to 15, such as 6 to 13, 6.5 to 12, 7 to 9.5, 7.5 to 9, or 7 to 9, across the entire base plate. With respect to the lower limit, the base plate may have a coefficient of thermal expansion greater than 5, such as greater than 6, greater than 6.5, greater than 7, or greater than 7.5. With respect to the upper limit, the base plate may have a coefficient of thermal expansion less than 15, such as less than 13, less than 12, less than 9.5, or less than 9. The coefficient of thermal expansion varies by less than 25%, such as less than 10%, less than 5%, less than 3%, or less than 1%, from the top to the bottom.

[0128] Combination of pedestal assemblies

[0138] The base plate and shaft of the present disclosure may be used in conjunction with each other. Alternatively, these components may be used in combination with other components known in the art. For example, the base plate of the present disclosure may be used together with a conventional shaft, or the shaft of the present disclosure may be used together with a conventional base plate.

[0129]

[0139] In some embodiments, the pedestal assembly includes the shaft and base plate of the present disclosure, which includes two or more (laminated) layers and / or co-fired ceramic materials. The layers may be adhered to each other with a brazing material. Examples of such base plates include those disclosed in U.S. Patent Nos. 7,667,944 and 5,737,178, which are incorporated herein by reference. In addition to the shaft and base plate, these assemblies may further include additional hardware, such as heating elements, antennas, and the like.

[0130]

[0140] The present disclosure also relates to a method of manufacturing a base plate. The base plate can be manufactured from two or more grades of raw material BeO powder. BeO powder can be used to form a precursor plate, which is then fired to obtain the base plate. In one embodiment, the upper surface includes a first grade and the lower portion includes a second grade, and the intermediate region includes a mixture of the first and second grades. Of course, various other numbers and combinations of the raw material BeO powder are contemplated.

[0131]

[0141] In one embodiment, the method includes supplying a first BeO powder and a third BeO powder, and forming a second powder from the first and third powders. The first and second powders may include different grades of raw material BeO. The method may further include forming a first (lower) region from the first powder, forming a second (intermediate) region from the second powder, and forming a third (upper) region from the third powder to form a base plate precursor. The forming steps can be achieved by dispensing each powder into a mold in a predetermined order. The second region can be disposed between the first and third regions. Additional regions formed from additional powders can also be formed in various configurations. The method may further include firing the base plate precursor to form the base plate.

[0132]

[0142] Importantly, in some cases, once the precursor is formed, mixing, e.g., vibrating (under optionally controlled conditions), may be performed to partially mix or bond the powders, which can result in a composition gradient after firing. Partial mixing is important to maintain the composition gradient. In some cases, insufficient mixing or complete non-mixing can result in a completely layered base plate, which may not achieve all of the benefits described herein. Excessive mixing can result in a uniform mixture of BeO powder with no desired composition gradient.

[0133]

[0143] The method may further include the step of placing at least one heating element within at least one region and / or the step of crimping the ends. The method further includes a step of cold forming and then firing (sintering) the base plate precursor to form the base plate.

[0134]

[0144] The shaft can be fabricated using a similar method.

[0145] Some embodiments relate to a method of manufacturing a pedestal assembly. The method includes supplying the base plate of the present disclosure and the shaft of the present disclosure, and connecting the shaft and the base plate.

Example

[0135] Examples 1 - 4 and Comparative Examples A - C

[0146] Examples 1 - 4 utilized coupons prepared from various BeO grades as shown in Table 1, and Comparative Examples A - C utilized coupons prepared from various AlN grades. The coupons were machined from large ceramic block pieces using standard diamond grinding and cleaning operations.

[0136]

Table 1

[0137]

[0147] As shown in Table 2, the dimensions of the coupons were consistent with various ASTM standards.

[0138]

Table 2

[0139]

[0148] Examples 1 to 4 and Comparative Examples A to C were tested for thermal diffusivity. The thermal diffusivity was measured in accordance with ASTM E1461-13 (2013) using a NETZSCH LFA467HT Hyperflash. The half-rise time was over 10 ms. The specimens were sputter-coated with 0.2 μm of gold and spray-coated with 5 μm of graphite. The specific heat was measured in accordance with ASTM E1269 (2013) using a Netzsch DSC 404 F1 Pegasus differential scanning calorimeter. The value at 25 °C was extrapolated and estimated.

[0140]

[0149] The results of the thermal diffusivity are shown in FIG. 1. As shown in FIG. 1, the BeO of Examples 1 to 4 beneficially demonstrated a significantly higher thermal diffusivity than Comparative Examples A to C of AlN at temperatures up to 500 °C. At temperatures above 500 °C, Examples 1 to 4 also showed a higher thermal diffusivity. The difference was not large but was still significant, and even a slight difference contributed to a remarkable improvement in performance.

[0141]

[0150] Examples 1 to 4 and Comparative Examples A to C were tested for specific heat. Specific heat is the amount of energy required to change the temperature of the body. The results of the specific heat are shown in FIG. 2. As shown in FIG. 2, the BeO of Examples 1 to 4 beneficially showed a higher specific heat value than Comparative Examples A to C of AlN. In fact, all of Examples 1 to 4 showed higher results than all of Comparative Examples A to C over the entire temperature range. Advantageously, Examples 1 to 4 reacted more slowly and produced force fluctuations (lower hysteresis) particularly when the operating temperature was reached.

[0142]

[0151] Examples 1 to 4 and Comparative Examples A to C were tested for thermal conductivity, and the results are shown in FIG. 3. The Fourier heat equation was applied to calculate the thermal conductivity from the specific heat, thermal diffusivity, and density. The thermal conductivity determines the steady-state thermal fluctuations of the body. As shown, the BeO of Examples 1 to 4 preferably reaches the steady-state temperature faster than Comparative Examples A to C of AlN at temperatures up to 500°C. At temperatures above 500°C, Examples 1 to 4 also showed higher thermal conductivity. The difference was not large but was still significant. Also, as in the case of the thermal diffusivity, even a slight difference contributes to a significant improvement in performance.

[0143]

[0152] Examples 1 to 4 and Comparative Examples A to C were measured for the penetration rate, and the results are shown in FIG. 4. The penetration rate was calculated from other heat values. The penetration rate controls the temperature at the moment of contact and contact of the two casings, for example, between the heating element and BeO and between BeO and the back He gas and Si wafer. As shown, the BeO of Examples 1 to 4 beneficially shows higher penetration rate values than Comparative Examples A to C of AlN over the entire temperature range. All of Examples 1 to 4 show higher penetration rate values than all of Comparative Examples A to C over the entire temperature range. Examples 1 to 4 remained at a more stable temperature with less temperature drop and had a lower thermal stress history compared to Comparative Examples A to C when in contact with the back gas and wafer.

[0144]

[0153] Examples 1 to 4 and Comparative Examples A to C were measured for the bulk resistivity, and the results are shown in FIG. 5. The bulk resistivity was measured using a Keithley 237HV source according to ASTM D257 / ASTM D1829, Procedure A. The bulk resistivity is related to (at high temperatures) clamping. A higher bulk resistivity is beneficial in the heating state. J-R clamping is generally electrostatically active in the range of 1×10 7 ~1×10 9 Ω-m (at 400 V to 600 V). FIG. 5 shows the resistivity gradients of the maximum values of Examples 1 to 4 and the maximum values of Comparative Examples A to C. The gradient of the curve is 1×10 7 ~1×10 9It is related to the time in the "checking / clamping zone" of Ω-m. As shown in Figure 5, Examples 1 to 4 are, surprisingly, quite flat curves and spend more time in the checking / clamping zone. This demonstrates improved clamping performance and results in the excellent clamping pressure performance disclosed herein, for example, a clamping pressure of at least 133 kPa.

[0145] Examples 5 and 6 Additional samples of the BeO material were tested for bulk resistivity in a similar manner. The composition of the BeO material is shown in Table 3. Examples 5 and 6 are prepared from mixtures of substantially similar ceramic powders. Examples 5 and 6 were measured at different times in different facilities. As shown in Figure 6, the curves of Examples 1, 5, and 6 are very similar and are within the expected typical batch-to-batch variations, especially within the checking / clamping region.

[0146]

Table 3

[0147]

[0154] The results are shown in Figure 6. As shown, Examples 1, 5, and 6 work particularly well, especially at high temperatures. Work particularly well.

[0148] Examples 7 and Comparative Example D

[0155] Example 7 utilized coupons containing a BeO composition containing BeO (purity over 99.5%). Comparative Example D utilized coupons containing an AlN composition. Examples 7 and Comparative Example D were tested for corrosion resistance by measuring the initial weight, treating, and then measuring the final weight. The treatment was 200 cycles (5.5 hours) in NF3 at 400 °C and 4 cycles (12 hours) in ClF at 300 °C. Example 7 surprisingly demonstrated an average loss rate of only 0.007 wt%, while Comparative Example D demonstrated an average loss rate of 0.016, more than twice that of Example 7 (the weight loss of Example 7 was 56% less than the weight loss of Comparative Example D).

[0149] Example 8

[0156] The base plate of Example 8 was prepared as follows. An instant (RTP: Ready to press) powder (high TC powder) containing BeO of a high thermal conductivity grade and optional binders, lubricants, and sintering aids was prepared. A similar powder was prepared using BeO of a low thermal conductivity grade (low TC powder). A predetermined amount of the high TC powder and the low TC powder were blended to produce an intermediate TC powder.

[0150]

[0157] The platen-shaped elastomer / graphite mold was filled with the high TC powder in the lower one-third volume. A niobium metal heating element in the form of a foil or coating or film or wire was placed in the powder bed. Then, the intermediate TC powder was added to the intermediate one-third volume. A metal ground plane or radio frequency antenna or niobium electrode was placed in the powder bed. Then, the upper one-third volume was filled with the low TC powder.

[0151]

[0158] Electrical connection posts and terminals were inserted through the entire powder layer and connected to the metal elements embedded therein. The mold was sealed and pressurized at room temperature to compress / densify the powder. The shape of the compressed powder was bonded by an organic or inorganic temporary binder and machined into a near-net shape object. Then the object was sintered in a furnace to induce densification. The object was machined to the finished dimension requirements, thus obtaining the final base plate having various property gradients disclosed herein. Forces and / or other connections were applied to the electrical connection posts to operate the device for heating and electrostatic chucking.

[0152]

[0159] The base plate was heated in a test chamber such that the surface of the silicon wafer placed on the base plate reached a temperature of 800 °C (the temperature at which the semiconductor manufacturing chamber is preferably operated). Surprisingly, the base plate operated very well at high temperatures. For example, the base plate did not crack and demonstrated a bulk resistivity performance similar to the above value (Figure 5), for example, resistivity. These unforeseen resistivity values correlate with excellent clamping performance at high temperatures (e.g., electrostatic chucking / clamping is maintained (at high temperatures)). Such performance was not achieved with conventional base plate materials, such as AlN.

[0153] Embodiment

[0160] In particular, the following embodiments are disclosed.

[0161] Embodiment 1: A pedestal assembly comprising a shaft containing a first beryllium oxide composition containing beryllium oxide and fluorine / fluoride ions, and a base plate containing a second beryllium oxide composition containing at least 95 wt% beryllium oxide and optional fluorine / fluoride ions, wherein the base plate demonstrates a clamping pressure of at least 133 kPa.

[0154]

[0162] Embodiment 2: The embodiment of Embodiment 1, wherein the first beryllium oxide composition contains 1 ppb to 1000 ppm of fluorine / fluoride ions.

[0163] Embodiment 3: The embodiment of Embodiment 1 or 2, wherein the first beryllium oxide composition contains more fluorine / fluoride ions than the second beryllium oxide composition.

[0155]

[0164] Embodiment 4: The embodiment of any one of Embodiments 1 to 3, wherein the first beryllium oxide composition is treated to achieve a fluorine / fluoride ion concentration.

[0165] Embodiment 5: The embodiment of any one of Embodiments 1 to 4, wherein the first beryllium oxide composition further contains less than 50 wt% magnesium oxide and less than 50 wt% ppm silicon dioxide.

[0156]

[0166] Embodiment 6: Any of Embodiments 1 to 5, wherein the first beryllium oxide composition further comprises 1 ppb to 50 wt% ppm of alumina, 1 ppb to 10,000 ppm of sulfite, and / or 1 ppb to 1 wt% ppm of boron, barium, sulfur, or lithium, or a combination thereof (including oxides, alloys, composites, or allotropes, or a combination thereof).

[0157]

[0167] Embodiment 7: Any of Embodiments 1 to 6, wherein the first beryllium oxide composition has an average grain boundary exceeding 0.1 micron.

[0168] Embodiment 8: Any of Embodiments 1 to 7, wherein the first beryllium oxide composition has an average particle size of less than 100 microns.

[0158]

[0169] Embodiment 9: Any of Embodiments 1 to 8, wherein the second beryllium oxide composition comprises 1 ppb to 10 wt% ppm of magnesium oxide and 1 ppb to 10 wt% ppm of silicon dioxide.

[0159]

[0170] Embodiment 10: Any of Embodiments 1 to 9, wherein the second beryllium oxide composition comprises 1 ppb to 10 wt% ppm of magnesium trisilicate.

[0171] Embodiment 11: Any of Embodiments 1 to 10, wherein the first beryllium oxide composition comprises more magnesium oxide and / or magnesium trisilicate than the second beryllium oxide composition.

[0160]

[0172] Embodiment 12: Any of Embodiments 1 to 11, wherein the second beryllium oxide composition comprises 1 ppb to 1 wt% of lithia.

[0173] Embodiment 13: Any of Embodiments 1 to 12, wherein the first beryllium oxide composition comprises less than 75 wt% of aluminum nitride and / or the second beryllium oxide composition comprises less than 5 wt% of aluminum nitride.

[0161]

[0174] Embodiment 14: Any one of Embodiments 1 to 13, wherein the first beryllium oxide composition has a conductivity of less than 300 W / m-K at room temperature.

[0175] Embodiment 15: Any one of Embodiments 1 to 14, wherein the second beryllium oxide composition has a conductivity of less than 400 W / m-K at room temperature.

[0162]

[0176] Embodiment 16: Any one of Embodiments 1 to 15, wherein the first beryllium oxide composition has a theoretical density in the range of 90% to 100%.

[0177] Embodiment 17: Any one of Embodiments 1 to 16, wherein the base plate demonstrates a temperature variation of less than ±3% when heated to a temperature above 700 °C.

[0163]

[0178] Embodiment 18: Any one of Embodiments 1 to 17, wherein the base plate demonstrates a bulk resistivity of greater than 1 × 10 4 ohm m at 800 °C.

[0179] Embodiment 19: Any one of Embodiments 1 to 18, wherein the base plate demonstrates a corrosion loss of less than 0.016 wt%.

[0164]

[0180] Embodiment 20: Any one of Embodiments 1 to 19, wherein the base plate has a dielectric constant of less than 20.

[0181] Embodiment 21: Any one of Embodiments 1 to 20, wherein the base plate has a surface hardness of at least 50 Rockwell on a 45N scale.

[0165]

[0182] Embodiment 22: Any one of Embodiments 1 to 21, wherein the base plate has a coefficient of thermal expansion in the range of 5 to 15 over the entire base plate.

[0183] Embodiment 23: Any one of Embodiments 1 to 22, further comprising a heating element sealed within the base plate.

[0166]

[0184] Embodiment 24: Any one of Embodiments 1 to 23, wherein the minimum lateral dimension across the entire base plate is at least 100 mm.

[0185] Embodiment 25: Any one of Embodiments 1 to 24, wherein the base plate has a flatness of less than 50 microns over a distance of 300 mm.

[0167]

[0186] Embodiment 26: Any one of Embodiments 1 to 25, wherein the base plate further optionally includes a mesa having a height greater than 1 micron.

[0187] Embodiment 27: Any one of Embodiments 1 to 26, wherein the shaft includes a stub portion having a similar coefficient of thermal expansion.

[0168]

[0188] Embodiment 28: Any one of Embodiments 1 to 27, wherein the base plate contains less than two layers of lamination.

[0189] Embodiment 29: Any one of Embodiments 1 to 28, wherein the base plate does not contain individual layers.

[0169]

[0190] Embodiment 30: A base plate having an upper and a lower part and containing a beryllium oxide composition containing at least 95 wt% beryllium oxide and optionally fluorine / fluoride ions, demonstrating a clamping pressure of at least 133 kPa at a temperature of at least 600 °C and a decomposition change of less than 1 wt% at a temperature above 1600 °C.

[0170]

[0191] Embodiment 31: The embodiment of Embodiment 30, wherein when the base plate is heated to a temperature exceeding 700 °C, it demonstrates a temperature variation of less than ±3%, and / or a bulk resistivity of more than 1×10 8 super, and / or a corrosion loss of less than 0.016 wt%, and / or a dielectric constant of less than 20, and / or a surface hardness of at least 50 Rockwell on the 45N scale, and / or a coefficient of thermal expansion in the range of 5 to 15 across the entire base plate.

[0171]

[0192] Embodiment 32: An embodiment according to Embodiment 30 or 31, wherein the coefficient of thermal expansion varies by less than 25% from the top to the bottom.

[0193] Embodiment 33: An embodiment according to any one of Embodiments 30 to 32, wherein the base plate demonstrates a cleaning cycle time of less than 2 hours and a temperature variation of less than ±3%.

[0172]

[0194] Embodiment 34: An embodiment according to any one of Embodiments 30 to 33, wherein the beryllium oxide composition contains 1 ppb to 10 wt% ppm of magnesium oxide and 1 ppb to 10 wt% ppm of silicon dioxide.

[0173]

[0195] Embodiment 35: An embodiment according to any one of Embodiments 30 to 34, wherein the beryllium oxide composition contains 1 ppb to 10 wt% ppm of magnesium trisilicate.

[0196] Embodiment 36: An embodiment according to any one of Embodiments 30 to 35, wherein the base plate does not contain individual layers.

[0174]

[0197] Embodiment 37: An embodiment according to any one of Embodiments 30 to 36, wherein the base plate has a thermal conductivity gradient that decreases from the top to the bottom, and / or a resistivity gradient that decreases from the top to the bottom, and / or a purity gradient that decreases from the top to the bottom, and / or a theoretical density gradient that decreases from the top to the bottom, and / or a dielectric constant gradient that increases from the top to the bottom.

[0175]

[0198] Embodiment 38: An embodiment according to any one of Embodiments 30 to 37, further comprising a heating element, an optional coiled and / or crimped heating element.

[0199] Embodiment 39: An embodiment according to any one of Embodiments 30 to 38, further comprising an antenna.

[0176]

[0200] Embodiment 40: An embodiment according to any one of Embodiments 30 to 39, wherein the heating element and / or the antenna contains niobium and / or platinum.

[0201] Embodiment 41: A base plate having an upper part and a lower part and containing a beryllium oxide composition, the base plate having a thermal conductivity gradient decreasing from the upper part to the lower part, and / or a resistivity gradient decreasing from the upper part to the lower part, and / or a purity gradient decreasing from the upper part to the lower part, and / or a theoretical density decreasing from the upper part to the lower part, and / or a dielectric constant gradient increasing from the upper part to the lower part.

[0177]

[0202] Embodiment 42: When measured at room temperature, the upper thermal conductivity is in the range of 125 to 400 W / mK, the lower thermal conductivity is in the range of 146 to 218 W / mK, and / or when measured at 800 °C, the upper thermal conductivity is in the range of 25 W / mK to 105 W / mK, and the lower thermal conductivity is in the range of 1 W / mK to 21 W / mK, which is an embodiment of Embodiment 41.

[0178]

[0203] Embodiment 43: When measured at room temperature, the upper thermal conductivity is at least 6% higher than the lower thermal conductivity, and / or when measured at 800 °C, the upper thermal conductivity is at least 6% higher than the lower thermal conductivity, which is an embodiment of Embodiment 41 or 42.

[0179]

[0204] Embodiment 44: The upper purity is in the range of 99.0 to 99.9, and the lower purity is in the range of 95.0 to 99.5, which is any one of Embodiments 41 to 43.

[0205] Embodiment 45: The upper purity is at least 0.4% higher than the lower purity, which is any one of Embodiments 41 to 44.

[0180]

[0206] Embodiment 46: The upper theoretical density is in the range of 93% to 100%, and the lower theoretical density is in the range of 93% to 100%, which is any one of Embodiments 41 to 45.

[0207] Embodiment 47: The upper theoretical density is at least 0.5% higher than the lower theoretical density, which is any one of Embodiments 41 to 46.

[0181]

[0208] Embodiment 48: Any one of Embodiments 41 to 47, wherein the upper dielectric constant is in the range of 1 to 20 and the lower dielectric constant is in the range of 1 to 20.

[0209] Embodiment 49: Any one of Embodiments 41 to 48, wherein the base plate does not include individual layers.

[0182]

[0210] Embodiment 50: Any one of Embodiments 41 to 49, wherein the base plate demonstrates a clamping pressure of at least 133 KPa.

[0211] Embodiment 51: Any one of Embodiments 41 to 50, wherein the base plate demonstrates a temperature variation of less than ±3% when heated to a temperature exceeding 700 °C.

[0183]

[0212] Embodiment 52: Any one of Embodiments 41 to 51, wherein the base plate demonstrates a corrosion loss of less than 0.016 wt%.

[0213] Embodiment 53: A shaft for a pedestal assembly including a beryllium oxide composition containing beryllium oxide and fluorine / fluoride ions, wherein the beryllium oxide composition has an average grain boundary or amorphous granular structure exceeding 0.1 micron.

[0184]

[0214] Embodiment 54: The embodiment of Embodiment 53, wherein the beryllium oxide composition has an average particle size of less than 100 microns.

[0215] Embodiment 55: The embodiment of Embodiment 53 or 54, wherein the beryllium oxide composition contains less than 75 wt% aluminum nitride.

[0185]

[0216] Embodiment 56: Any one of Embodiments 53 to 55, wherein the first beryllium oxide composition has a thermal conductivity of less than 300 W / m-K at room temperature.

[0217] Embodiment 57: Any one of Embodiments 53 to 56, wherein the beryllium oxide composition has a theoretical density in the range of 90 to 100.

[0186]

[0218] Embodiment 58: Any one of Embodiments 53 to 57, wherein when measured at room temperature, the upper thermal conductivity is in the range of 146 W / mK to 218 W / mK, the lower thermal conductivity is in the range of 1 W / mK to 218 W / mK, and / or when measured at 800 °C, the upper thermal conductivity is in the range of 1 W / mK to 21 W / mK, and the lower thermal conductivity is in the range of 1 W / mK to 21 W / mK.

[0187]

[0219] Embodiment 59: Any one of Embodiments 53 to 58, wherein the upper theoretical density is at least 0.5% higher than the lower theoretical density.

[0220] Embodiment 60: Any one of Embodiments 53 to 59, wherein the first beryllium oxide composition contains 1 ppb to 1000 ppm of fluorine / fluoride ions.

[0188]

[0221] Embodiment 61: Any one of Embodiments 53 to 60, wherein the first beryllium oxide composition further contains less than 50 wt% of magnesium oxide and less than 50 wt% ppm of silicon dioxide.

[0189]

[0222] Embodiment 62: Any one of Embodiments 53 to 61, wherein the first beryllium oxide composition further contains 1 ppb to 50 wt% ppm of alumina, 1 ppb to 10000 ppm of sulfite, and / or 1 ppb to 1 wt% ppm of boron, barium, sulfur, or lithium, or a combination thereof (including oxides, alloys, composites, or allotropes, or a combination thereof).

[0190]

[0223] Embodiment 63: A pedestal assembly including a shaft according to any one of Embodiments 53 to 62, a base plate containing a plurality of layers joined to each other by a brazing material optionally, and an optional printed heating element.

[0191]

[0224] Embodiment 64: A base plate having an upper and a lower part and containing a ceramic composition, having a clamping pressure of at least 133 kPa, a temperature variation of less than ±3% when heated to a temperature above 700 °C, and / or 1×10 at 800 °C8 A base plate demonstrating a super bulk resistivity, and / or a corrosion loss of less than 0.016 wt%, and / or a dielectric constant of less than 20, and / or a surface hardness of at least 50 Rockwell on the 45N scale, and / or a coefficient of thermal expansion in the range of 5 to 15 across the entire base plate.

[0192]

[0225] Embodiment 65: A method of manufacturing a base plate, comprising the steps of supplying a first BeO powder and a third BeO powder, and forming a second powder from the first and third powders A step of forming a first (lower) region from the first powder, a step of forming a second (middle) region from the second powder, and a step of forming a third (upper) region from the third powder to form a base plate precursor, wherein the second region is disposed between the first and third regions, and a step of firing the base plate precursor to form a base plate.

[0193]

[0226] Embodiment 66: The embodiment of Embodiment 65, wherein the first and third (and second) powders contain different grades of raw material BeO.

[0227] Embodiment 67: The embodiment of Embodiment 65 or 66, further comprising the step of placing a heating element within a region and / or the step of crimping an end.

[0194]

[0228] Embodiment 68: Any of the embodiments of Embodiments 65 to 67, further comprising the step of mixing the base plate precursor to bond the powders.

[0229] Embodiment 69: Any of the embodiments of Embodiments 65 to 68, further comprising the step of cold-forming the base plate precursor.

[0195]

[0230] Embodiment 70: A method of manufacturing a pedestal shaft, comprising the step of treating a beryllium oxide composition to achieve a fluorine / fluoride ion concentration in the range of 1 ppb to 1000 ppm of fluorine / fluoride ions.

[0196]

[0231] Embodiment 71: A method for cleaning a contaminated pedestal assembly, comprising the steps of providing a pedestal assembly and a wafer with the wafer disposed on top of the pedestal assembly, heating the wafer to a temperature above 600°C, cooling the wafer to a cooling temperature (or not cooling it at all) by a width of less than 100°C, cleaning the plate at the cooling temperature, and optionally reheating the wafer to 600°C, wherein the cleaning cycle time from the cooling step to the reheating step is less than 2 hours.

[0197]

[0232] Embodiment 72: The embodiment of Embodiment 71, wherein the cleaning cycle time ranges from 0 to 10 minutes.

[0233] Embodiment 73: A base plate comprising a beryllium oxide composition having upper and lower portions and containing at least 95 wt% beryllium oxide and optionally fluorine / fluoride ions, demonstrating a bulk resistivity of more than 1×10 5 ohm m at a temperature of at least 600°C with a clamping pressure of at least 133 kPa and at 800°C.

[0198]

[0234] Embodiment 74: The embodiment of Embodiment 73, wherein the base plate demonstrates a temperature variation of less than ±3% when heated to a temperature above 700°C, and / or a decomposition change of less than 1 wt% at a temperature above 1600°C, and / or a dielectric constant of less than 20, and / or a surface hardness of at least 50 Rockwell on a 45N scale, and / or a thermal expansion coefficient in the range of 5 to 15 across the entire base plate.

[0199]

[0235] Embodiment 75: The embodiment of Embodiment 73 or 74, wherein the base plate comprises a beryllium oxide composition containing 1 ppm to 5 wt% ppm magnesium oxide, 1 ppm to 5 wt% silicon dioxide, and 1 ppb to less than 5 wt% ppm magnesium trisilicate.

[0200]

[0236] Embodiment 76: Any one of Embodiments 73 to 75, wherein the coefficient of thermal expansion varies by less than 25% from the top to the bottom.

[0237] Embodiment 77: Any one of Embodiments 73 to 76, wherein the base plate demonstrates a corrosion loss of less than 0.016 wt%.

[0201]

[0238] Embodiment 78: Any one of Embodiments 73 to 77, wherein the base plate demonstrates a cleaning cycle time of less than 2 hours and a temperature variation of less than ±3%.

[0239] Embodiment 79: Any one of Embodiments 73 to 78, wherein the base plate does not include individual layers.

[0202]

[0240] Embodiment 80: Any one of Embodiments 73 to 79, wherein the base plate demonstrates a temperature variation of less than ±3% when heated to a temperature above 700 °C.

[0241] Embodiment 81: Any one of Embodiments 73 to 80, wherein the base plate has a thermal conductivity gradient decreasing from the top to the bottom, a resistivity gradient decreasing from the top to the bottom, and a purity gradient decreasing from the top to the bottom.

[0203]

[0242] Embodiment 82: Any one of Embodiments 73 to 81, wherein the upper purity is at least 0.4% higher than the lower purity.

[0243] Embodiment 83: A pedestal assembly including a shaft containing a first beryllium oxide composition containing beryllium oxide and fluorine / fluoride ions, and a base plate containing a second beryllium oxide composition containing at least 95 wt% beryllium oxide, wherein the base plate demonstrates a bulk resistivity of more than 1 × 10 5 ohm m at a temperature of at least 600 °C with a clamping pressure of at least 133 kPa and at 800 °C.

[0204]

[0244] Embodiment 84: The embodiment of Embodiment 83, wherein the first beryllium oxide composition has an average grain boundary of more than 0.1 micron.

[0245] Embodiment 85: The embodiment of Embodiment 83 or 84, wherein the first beryllium oxide composition has an average particle size of less than 100 microns.

[0205]

[0246] Embodiment 86: The embodiment of any one of Embodiments 83 to 85, wherein the first beryllium oxide composition contains 10 ppb to 800 ppm of fluorine / fluoride ions.

[0247] Embodiment 87: The embodiment of any one of Embodiments 83 to 86, wherein the first beryllium oxide composition contains more fluorine / fluoride ions than the second beryllium oxide composition.

[0206]

[0248] Embodiment 88: The embodiment of any one of Embodiments 83 to 87, wherein the first beryllium oxide composition further contains 1 ppb to 50 wt% ppm of alumina, 1 ppb to 10,000 ppm of sulfite, and / or 1 ppb to 1 wt% ppm of boron, barium, sulfur, or lithium, or a combination thereof (including oxides, alloys, composites, or allotropes, or a combination thereof).

[0207]

[0249] Embodiment 89: The embodiment of any one of Embodiments 83 to 88, wherein the first beryllium oxide composition contains less than 75 wt% of aluminum nitride, and the second beryllium oxide composition contains less than 5 wt% of aluminum nitride.

[0208]

[0250] Embodiment 90: A shaft for a pedestal assembly including a beryllium oxide composition containing beryllium oxide and 10 ppb to 800 ppm of fluorine / fluoride ions, wherein the beryllium oxide composition has an average grain boundary or amorphous granular structure of more than 0.1 micron and an average particle size of less than 100 microns.

[0209]

[0251] Embodiment 91: A method of manufacturing a base plate, comprising the steps of supplying a first BeO powder and a third BeO powder; forming a second powder from the first and third powders; forming a first (lower) region from the first powder; forming a second (middle) region from the second powder; and forming a third (upper) region from the third powder to form a base plate precursor, wherein the second region is disposed between the first and third regions; and firing the base plate precursor to form a base plate. The method further includes the step of firing the base plate precursor to form a base plate.

[0210]

[0252] Embodiment 92: Embodiment 91, wherein the first and third, and optionally the second powder, comprise different grades of raw material BeO.

[0253] Although the present invention has been described in detail, modifications within the spirit and scope of the present invention will be readily understood by those skilled in the art. Considering the foregoing description, all relevant knowledge in the technical field and the above references are hereby incorporated by reference into this specification in relation to the disclosures of "Background Art" and "Modes for Carrying Out the Invention". In addition, aspects of the present invention, as well as parts of various embodiments and various features within the following and / or appended claims, may be combined or exchanged in whole or in part. In the foregoing descriptions of the various embodiments, embodiments that refer to other embodiments may, where appropriate, be combined with the other embodiments, as will be understood by those skilled in the art. Furthermore, those skilled in the art will understand that the foregoing description is illustrative only and not intended to be limiting.

Claims

1. A base plate comprising a beryllium oxide composition having upper and lower portions and containing at least 95 wt% beryllium oxide and optionally fluorine / fluoride ions, the base plate demonstrating a bulk resistivity of greater than 1 × 10 ５ ohm m at a temperature of at least 600 °C and a clamping pressure of at least 133 kPa and at 800 °C.

2. The base plate according to claim 1, wherein the base plate comprises a beryllium oxide composition containing magnesium oxide of 1 ppm to 5 wt% ppm, silicon dioxide of 1 ppm to 5 wt%, and magnesium trisilicate of more than 1 ppm and less than 5 wt% ppm.

3. The base plate, when heated to a temperature exceeding 700 °C, has a temperature fluctuation of less than ±3%, and / or at a temperature exceeding 1600 °C, has a decomposition change of less than 1 wt%, and / or has a dielectric constant of less than 20, and / or has a surface hardness of at least 50 Rockwell on a 45 N scale, and / or has a coefficient of thermal expansion in the range of 5 to 15 over the entire base plate The base plate according to claim 1, which demonstrates.

4. The base plate according to claim 1, wherein the coefficient of thermal expansion varies by less than 25% from the top to the bottom.

5. The base plate according to claim 1, wherein the base plate demonstrates a corrosion loss of less than 0.016 wt%.

6. The base plate according to claim 1, wherein the base plate demonstrates a cleaning cycle time of less than 2 hours and a temperature fluctuation of less than ±3%.

7. The base plate according to claim 1, wherein the base plate does not include individual layers.

8. The base plate according to claim 1, wherein the base plate demonstrates a temperature fluctuation of less than ±3% when heated to a temperature exceeding 700 °C.

9. The base plate according to claim 1, wherein the base plate has a thermal conductivity gradient decreasing from top to bottom, a resistivity gradient decreasing from top to bottom, and a purity gradient decreasing from top to bottom.

10. The base plate according to claim 1, wherein the top purity is at least 0.4% higher than the bottom purity.

11. A pedestal assembly, a shaft containing a first beryllium oxide composition containing beryllium oxide and fluorine / fluoride ions, a base plate containing a second beryllium oxide composition containing at least 95 wt% beryllium oxide, comprising The pedestal assembly, wherein the base plate demonstrates a bulk resistivity of at least 1 × 10 ５ ohm m or more at a tightening pressure of at least 133 kPa and a temperature of at least 600 °C and at 800 °C.

12. The assembly according to claim 11, wherein the first beryllium oxide composition has an average grain boundary exceeding 0.1 micron.

13. The assembly according to claim 11, wherein the first beryllium oxide composition has an average particle size of less than 100 microns.

14. The assembly according to claim 11, wherein the first beryllium oxide composition contains 10 ppb to 800 ppm of fluorine / fluoride ions.

15. The assembly according to any one of claims 11 to 14, wherein the first beryllium oxide composition contains more fluorine / fluoride ions than the second beryllium oxide composition.

16. The first beryllium oxide composition contains 1 ppb to 50 wt% ppm of alumina, 1 ppb to 10,000 ppm of sulfite, and / or 1 ppb to 1 wt% ppm of boron, barium, sulfur, or lithium, or a combination thereof (including oxides, alloys, composites, or allotropes, or a combination thereof) The assembly according to claim 11, further comprising.

17. The assembly according to claim 11, wherein the first beryllium oxide composition contains less than 75 wt% of aluminum nitride, and the second beryllium oxide composition contains less than 5 wt% of aluminum nitride.

18. A shaft for a pedestal assembly comprising beryllium oxide and a beryllium oxide composition containing 10 ppb to 800 ppm of fluorine / fluoride ions, wherein the beryllium oxide composition has an average grain boundary or amorphous granular structure greater than 0.1 micron and an average particle size less than 100 microns.

19. A method of manufacturing a base plate, comprising the steps of supplying a first BeO powder and a third BeO powder; forming a second powder from the first and third powders; forming a first (lower) region from the first powder; forming a second (intermediate) region from the second powder; forming a third (upper) region from the third powder to form a base plate precursor, wherein the second region is disposed between the first and third regions; firing the base plate precursor to form the base plate; The method comprising.

20. The method according to claim 19, wherein the first, third, and optionally second powders contain different grades of raw material BeO.

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