Heater for semiconductor manufacturing apparatus

Abstract

Provided is a heater for a semiconductor manufacturing apparatus capable of improving the volume resistivity of a ceramic substrate and being stably manufactured. A heater for a semiconductor manufacturing apparatus according to an embodiment of the present invention comprises a ceramic substrate and a heating element. The ceramic substrate contains aluminum nitride. The heating element is embedded in the ceramic substrate. The ceramic substrate contains two or more kinds of rare earth elements and contains Yb as a rare earth element. The total content ratio of the rare earth elements in the ceramic substrate is 4.5 mass % or less in terms of oxide. The content ratio of Yb in the ceramic substrate is 0.3 mass % or more and 1.3 mass % or less in terms of oxide.

Description

Semiconductor manufacturing equipment heaters

[0001] The present invention relates to a heater for use in semiconductor manufacturing equipment.

[0002] Conventionally, in the manufacture of semiconductor devices, heaters for semiconductor manufacturing equipment are used to support and heat semiconductor substrates. A typical heater for semiconductor manufacturing equipment includes a ceramic base and a heating element embedded in the ceramic base. For example, a ceramic heater has been proposed for such a heater for semiconductor manufacturing equipment, in which the heating element includes a metal such as molybdenum (Mo) or tungsten (W), and the ceramic base includes 91 to 99 mass % aluminum nitride and 1 to 9 wt % rare earth element oxide (see Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2002-141163

[0004] In heaters for semiconductor manufacturing equipment, such as the ceramic heater described in Patent Document 1, it is desirable to increase the thermal conductivity of the ceramic base. Therefore, studies have been conducted to increase the thermal conductivity of the ceramic base by adding rare earth element oxides to the ceramic base. However, simply adding a large amount of rare earth element oxide to the ceramic base increases the difference between the linear expansion coefficient of the ceramic base and the linear expansion coefficient of the heating element, which may cause damage such as cracks in the ceramic base during the manufacture of the heater for semiconductor manufacturing equipment. Therefore, there is room for improvement in both improving the volume resistivity of the ceramic base and ensuring the manufacturing stability of the heater for semiconductor manufacturing equipment. The primary object of the present invention is to provide a heater for semiconductor manufacturing equipment that can improve the volume resistivity of the ceramic base and can be manufactured stably.

[0005] [1] A heater for semiconductor manufacturing equipment according to an embodiment of the present invention includes a ceramic base and a heating element. The ceramic base includes aluminum nitride. The heating element is embedded in the ceramic base. The ceramic base includes two or more rare earth elements, and contains Yb as a rare earth element. The total content of rare earth elements in the ceramic base is 4.5 mass % or less, calculated as oxides. The content of Yb in the ceramic base is 0.3 mass % or less and 1.3 mass % or less, calculated as oxides. [2] In the heater for semiconductor manufacturing equipment described in [1] above, the volume resistivity of the ceramic base at 500°C is 1 x 10 ９ [3] In the heater for semiconductor manufacturing equipment described in [1] or [2] above, the ceramic base may further contain Y as the rare earth element. [4] In the heater for semiconductor manufacturing equipment described in any one of [1] to [3] above, the content of Ca in the ceramic base may be 300 ppm or less.

[0006] According to the embodiments of the present invention, it is possible to improve the volume resistivity of the ceramic base and realize a heater for semiconductor manufacturing equipment that can be stably manufactured.

[0007] FIG. 1 is a schematic diagram of a heater for use in semiconductor manufacturing equipment according to one embodiment of the present invention.

[0008] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments. In addition, in order to clarify the explanation, the width, thickness, shape, etc. of each part may be shown schematically in the drawings compared to the embodiments, but this is merely an example and does not limit the interpretation of the present invention.

[0009] A. Overview of the Semiconductor Manufacturing Equipment Heater Fig. 1 is a schematic cross-sectional view of a semiconductor manufacturing equipment heater according to one embodiment of the present invention. A semiconductor manufacturing equipment heater 100 according to one embodiment of the present invention is typically capable of supporting and heating a semiconductor substrate 8.

[0010] The heater 100 for semiconductor manufacturing equipment includes a ceramic base 1 and a heating element 2. The ceramic base 1 contains aluminum nitride (AlN) as a main component. The ceramic base 1 contains two or more rare earth elements, including Yb as a rare earth element. The total content of rare earth elements in the ceramic base 1 is 4.5 mass% or less, calculated as oxides. The content of Yb in the ceramic base 1 is 0.3 mass% to 1.3 mass%, calculated as oxides. The heating element 2 is embedded in the ceramic base 1. With this configuration, the total content of rare earth elements in the ceramic base is 4.5 mass% or less, thereby stably reducing the difference in linear expansion coefficient between the ceramic base and the heating element. Furthermore, the ceramic base contains 0.3 mass% to 1.3 mass% of Yb among the two or more rare earth elements, thereby sufficiently increasing the volume resistivity of the ceramic base. Furthermore, when the Yb content in the ceramic base is within this range, color unevenness in the ceramic base can be sufficiently suppressed, and therefore heaters for semiconductor manufacturing equipment including ceramic bases with excellent volume resistivity can be stably manufactured.

[0011] The total content of rare earth elements in the ceramic base 1 is, for example, 0.5 mass % or more, preferably 1.0 mass % or more, and more preferably 3.0 mass % or more, calculated as oxides. When the total content of rare earth elements in the ceramic base is within this range, the volume resistivity of the ceramic base can be stably increased. The content of each component in the ceramic base is measured, for example, by inductively coupled plasma atomic emission spectroscopy (ICP-AES).

[0012] The content of Yb in the ceramic base 1 is, for example, 0.3 mass % or more, preferably 0.6 mass % or more, and more preferably 0.9 mass % or more, calculated as oxide. When the content of Yb in the ceramic base is within this range, color unevenness of the ceramic base can be stably suppressed, and the volume resistivity of the ceramic base can be more stably increased.

[0013] In one embodiment, the ceramic base 1 further contains Y as a rare earth element. When the ceramic base contains both Yb and Y, it is possible to stably achieve both an improvement in the volume resistivity of the ceramic base and an improvement in the manufacturing stability of the heater for semiconductor manufacturing equipment. The Y content in the ceramic base 1 is, for example, 2.0 mass% or more, preferably 2.5 mass% or more, calculated as oxide. On the other hand, the Y content in the ceramic base 1 is, for example, 4.0 mass% or less, or, for example, 3.5 mass% or less. The mass ratio of Yb to Y (Yb:Y) in the ceramic base 1 is, for example, 1:2 to 1:10, preferably 1:2 to 1:7.5, and more preferably 1:2 to 1:5.

[0014] The ceramic base 1 may further contain other rare earth elements in addition to Yb and Y, or may contain only Yb and Y as rare earth elements. In one embodiment, the ceramic base 1 contains only Yb and Y as rare earth elements and is substantially free of other rare earth elements. The content of the other rare earth elements in the ceramic base 1 is, for example, 0.5 mass% or less in terms of oxide. This makes it possible to more stably achieve both an improvement in the volume resistivity of the ceramic base and an improvement in the manufacturing stability of the heater for semiconductor manufacturing equipment. Examples of other rare earth elements include Ce.

[0015] The content of AlN in the ceramic base 1 is, for example, 90.0 mass % or more, preferably 93.0 mass % or more. On the other hand, the content of AlN in the ceramic base 1 is, for example, 99.0 mass % or less, preferably 95.0 mass % or less.

[0016] The ceramic base 1 may further contain trace components in addition to AlN and rare earth elements. Examples of trace components include O, C, Ti, Ca, Mg, Si, and Fe. The trace components may be contained alone or in combination of two or more in the ceramic base. The content of the trace components in the ceramic base 1 is, for example, 0.1 mass% or less, preferably 0.05 mass% or less. In particular, the content of Ca in the ceramic base 1 is, for example, 300 ppm or less, preferably 280 ppm or less, and more preferably 230 ppm or less. When the content of Ca in the ceramic base is below this upper limit, the volume resistivity of the ceramic base can be stably improved.

[0017] Such a ceramic base 1 has a relatively high volume resistivity. The volume resistivity of the ceramic base 1 at 500° C. is, for example, 1.0×10 ９ Ω cm or more, preferably 5.0 × 10 ９ Ω cm or more, more preferably 7.5×10 ９ On the other hand, the upper limit of the volume resistivity of the ceramic substrate 1 at 500°C is typically 1.0 × 10 １０ The volume resistivity at 500° C. is measured in accordance with, for example, JIS C2141-1992.

[0018] The thermal conductivity of the ceramic base 1 at 500° C. is, for example, 60 W / m·K to 90 W / m·K, and preferably 70 W / m·K to 80 W / m·K. The thermal conductivity of the ceramic base at 500° C. is measured in accordance with, for example, JIS R1611.

[0019] The average linear expansion coefficient of the ceramic base 1 in the temperature range of 50° C. to 1000° C. is, for example, 5.3 ppm / ° C. to 5.9 ppm / ° C., and preferably 5.5 ppm / ° C. to 5.8 ppm / ° C. The average linear expansion coefficient is measured in accordance with, for example, JIS R1618.

[0020] The heating element 2 contains any appropriate metal. Examples of metals include tantalum (Ta), tungsten (W), molybdenum (Mo), tungsten carbide (WC), titanium nitride (TiN), platinum (Pt), rhenium (Re), hafnium (Hf), and alloys thereof. Among the metals, W, Mo, and W-Mo alloys are preferred. When the heating element contains such a metal, the linear expansion coefficient of the ceramic base and the linear expansion coefficient of the heating element can be stably brought closer together. This can further improve the manufacturing stability of heaters for semiconductor manufacturing equipment.

[0021] The average linear expansion coefficient of the heating element 2 in the temperature range of 50°C to 1000°C is, for example, 5.4 ppm / °C to 6.0 ppm / °C, and preferably 5.6 ppm / °C to 5.9 ppm / °C. The absolute value of the difference in the average linear expansion coefficient between the ceramic base 1 and the resistance heating element 2 in the temperature range of 50°C to 1000°C is, for example, 0.5 ppm / °C or less, and preferably 0.3 ppm / °C or less. On the other hand, the lower limit of the absolute value of the difference in the average linear expansion coefficient between the ceramic base 1 and the resistance heating element 2 is typically 0.1 ppm / °C.

[0022] B. Details of the Semiconductor Manufacturing Equipment Heater Hereinafter, each component of the semiconductor manufacturing equipment heater will be described in detail.

[0023] B-1. Ceramic Base The ceramic base 1 can have any appropriate shape depending on the application of the heater for semiconductor manufacturing equipment. A typical shape of the ceramic base 1 is a plate shape. The ceramic base 1 preferably has a disk shape. The ceramic base 1 typically has a mounting surface 1a on which a semiconductor substrate 8 can be placed. The mounting surface 1a is one surface of the ceramic base 1 in the thickness direction. The thickness of the ceramic base 1 is, for example, 10 mm to 40 mm.

[0024] As described above, the ceramic substrate 1 contains AlN as a main component and two or more rare earth elements including Yb as sub-components. Such a ceramic substrate 1 typically contains an AlN crystal phase and an ytterbium aluminate crystal phase.

[0025] In one embodiment, the AlN crystalline phase has a polycrystalline structure in which a plurality of AlN crystalline grains are bonded to one another. The average grain size of the plurality of AlN crystalline grains is, for example, 2 μm to 5 μm, preferably 3 μm to 4.5 μm. The ytterbium aluminate crystalline phase is typically present at the grain boundaries between the AlN grains.

[0026] When the rare earth element includes yttrium (Y) in addition to Yb, the ceramic substrate 1 further includes an yttrium aluminate crystalline phase, which typically exists at the grain boundaries between AlN grains.

[0027] The ceramic substrate 1 may further contain other crystalline phases in addition to the AlN crystalline phase, the ytterbium aluminate crystalline phase, and the yttrium aluminate crystalline phase, or may be substantially free of other crystalline phases. In one embodiment, the ceramic substrate 1 contains only the AlN crystalline phase, the ytterbium aluminate crystalline phase, and the yttrium aluminate crystalline phase as crystalline phases, and is substantially free of other crystalline phases.

[0028] The porosity of the ceramic substrate 1 is, for example, 1% or less. The porosity is measured in accordance with, for example, JIS R1634.

[0029] The relative density of the ceramic base 1 is, for example, 3.2 g / cc to 3.4 g / cc, and preferably 3.25 g / cc to 3.35 g / cc. The relative density of the ceramic base is the bulk density relative to the theoretical density of the ceramic base. The bulk density of the ceramic base is measured, for example, in accordance with JIS R1634.

[0030] In the illustrated example, the ceramic base 1 is supported by a ceramic shaft 5. The ceramic shaft 5 is connected to the surface of the ceramic base 1 opposite to the mounting surface 1a.

[0031] The ceramic shaft 5 has any appropriate shape. In one embodiment, the ceramic shaft 5 has a cylindrical shape extending in the thickness direction of the ceramic base 1. In the illustrated example, the axis of the ceramic shaft 5 and the center of the ceramic base 1 substantially coincide with each other when viewed in the thickness direction of the ceramic base 1. The ceramic shaft 5 is made of any appropriate ceramic material, but from the viewpoint of matching the thermal expansion difference with the ceramic base, a ceramic shaft made of the same material as the ceramic base, i.e., containing aluminum nitride, is preferred.

[0032] B-2. Heating element The heating element 2 is configured to generate heat when a voltage is applied. There is no particular limit to the number of heating elements 2 embedded in the ceramic base 1. A plurality of heating elements 2 may be embedded in the ceramic base 1. In this case, the plurality of heating elements 2 are positioned apart from one another in the thickness direction of the ceramic base 1. In the illustrated example, one heating element 2 is embedded in the ceramic base 1.

[0033] The heating element 2 has any appropriate shape. Examples of the heating element 2 include a coil shape, a zigzag shape, and a mesh shape. The dimension (wire diameter) of the heating element 2 in the thickness direction of the ceramic base 1 is, for example, 0.3 mm to 1.0 mm, and preferably 0.4 mm to 0.7 mm.

[0034] The volume resistivity of the heating element 2 at 500°C is, for example, 1.9×10 －５ Ω cm or less, preferably 1.8×10 －５ On the other hand, the lower limit of the volume resistivity of the heating element 2 at 500°C is typically 1.6 × 10 －５ It is Ω·cm.

[0035] In the illustrated example, a first power supply rod 6 is electrically connected to the heating element 2. A voltage can be applied to the heating element 2 via the first power supply rod 6. The first power supply rod 6 is made of any appropriate conductive material. The first power supply rod 6 passes through the internal space of the ceramic shaft 5 and is electrically connected to the heating element 2.

[0036] B-3. ​​Internal Electrode In one embodiment, the heater 100 for semiconductor manufacturing equipment further includes an internal electrode 3. The internal electrode 3 is embedded in the ceramic base 1. In the illustrated example, the internal electrode 3 is located between the mounting surface 1a and the heating element 2 in the thickness direction of the ceramic base 1.

[0037] The internal electrode 3 typically functions as an ESC electrode. When the internal electrode 3 functions as an ESC electrode, when a DC voltage is applied to the internal electrode 3 with the semiconductor substrate 8 placed on the mounting surface 1 a, the internal electrode 3 is charged with either a positive or negative charge depending on the polarity of the applied DC voltage, and the other of the positive and negative charges present in the semiconductor substrate 8 moves toward the mounting surface 1 a of the semiconductor substrate 8. As a result, a Johnsen-Rahbek (JR) force is generated between the semiconductor substrate 8 and the internal electrode 3, and the semiconductor substrate 8 is chucked to the ceramic base 1. Although not shown, the heater 100 for semiconductor manufacturing equipment may include a plurality of internal electrodes 3.

[0038] In one embodiment, the internal electrode 3 functions as an RF electrode (i.e., a radio frequency electrode) for plasma processing. That is, the internal electrode 3 preferably functions as an RF / ESC electrode. Examples of plasma processing include film formation processing and etching processing. When such plasma processing is performed on a semiconductor substrate 8 on the mounting surface 1a, an upper electrode is disposed on the opposite side of the semiconductor substrate 8 from the internal electrode 3. In this state, when radio frequency power is supplied to the internal electrode 3, a processing gas can be excited in the space between the ceramic base 1 and the upper electrode to generate plasma. The plasma processing is performed on the semiconductor substrate 8 by the plasma.

[0039] The internal electrode 3 may have any appropriate shape. The internal electrode 3 typically has a plate shape. In one embodiment, the internal electrode 3 has a shape similar to the outer shape of the ceramic base 1 when viewed in the thickness direction of the ceramic base 1. In the illustrated example, the center of the internal electrode 3 and the center of the ceramic base 1 substantially coincide with each other when viewed in the thickness direction of the ceramic base 1. The thickness of the internal electrode 3 is, for example, 0.2 mm to 0.8 mm.

[0040] The internal electrode 3 typically contains the same metal as the heating element 2 described above. Therefore, the range of the average linear expansion coefficient of the internal electrode 3 in the temperature range of 50°C to 1000°C is, for example, the same as the range of the average linear expansion coefficient of the heating element 2 described above. Furthermore, the range of the absolute value of the difference in the average linear expansion coefficient between the ceramic base 1 and the internal electrode 3 in the temperature range of 50°C to 1000°C is, for example, the same as the range of the absolute value of the difference in the average linear expansion coefficient between the ceramic base 1 and the heating element 2 described above. This makes it possible to suppress damage such as cracks in the ceramic base during the manufacture of the heater for semiconductor manufacturing equipment, even if the heater for semiconductor manufacturing equipment includes an internal electrode.

[0041] In the illustrated example, a second power feed rod 7 is electrically connected to the internal electrode 3. The above-mentioned voltage (or high-frequency power) can be applied to the internal electrode 3 via the second power feed rod 7. The second power feed rod 7 is typically made of the same metal as the internal electrode 3. The second power feed rod 7 passes through the internal space of the ceramic shaft 5 and is electrically connected to the internal electrode 3.

[0042] C. Manufacturing Method of a Heater for Semiconductor Manufacturing Equipment Next, a manufacturing method of a heater for semiconductor manufacturing equipment according to one embodiment will be described. The manufacturing method of a heater for semiconductor manufacturing equipment according to one embodiment includes a mixing step of mixing raw material powders for a ceramic base, a molding step of preparing a molded body having an embedded heating element from the raw material mixture obtained in the mixing step and the heating element, and a firing step of firing the molded body obtained in the molding step.

[0043] C-1. Mixing Step In the mixing step, AlN powder and two or more rare earth element powders are mixed to prepare a mixed powder. ２ O ３ Powder and Y ２ O ３ The powder is mixed to prepare a raw material mixture.

[0044] Yb ２ O ３The amount of the powder added is, for example, 0.05 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 0.8 parts by mass or more, relative to 100 parts by mass of the AlN powder. ２ O ３ The upper limit of the amount of powder added is typically 1.3 parts by mass per 100 parts by mass of AlN powder.

[0045] Y ２ O ３ The amount of the powder added is, for example, 0.5 parts by mass or more, preferably 1.0 parts by mass or more, and more preferably 3.0 parts by mass or more, relative to 100 parts by mass of AlN. ２ O ３ The upper limit of the amount of addition is typically 4.3 parts by mass per 100 parts by mass of the AlN powder.

[0046] In the mixing step, any appropriate mixing device can be used, for example, a ball mill, a bead mill, or a vibration mill, and preferably a ball mill.

[0047] The mixing method in the mixing step may be dry mixing or wet mixing. In one embodiment, dry mixing is performed in the mixing step.

[0048] The environmental conditions for the mixing step are not particularly limited. The mixing step is typically carried out at room temperature (25°C) and atmospheric pressure (0.1 MPa). The duration of the mixing step is set arbitrarily and appropriately. The duration of the mixing step is, for example, 1 hour to 30 hours.

[0049] As a result of the above, AlN powder and two or more rare earth element powders (typically Yb ２ O ３ Powder and Y ２ O ３ When the mixing step is dry mixing, the raw material mixture is in a powder state, and when the mixing step is wet mixing, the raw material mixture is in a slurry state.

[0050] The raw material mixture is granulated as needed. For example, a spray dryer can be used to prepare a granulated product (raw material granules) of the raw material mixture.

[0051] C-2. Molding Step Next, in the molding step, the raw material mixture is molded by any appropriate molding method with the heating element 2 prepared in advance embedded in the raw material mixture at a desired position. Examples of molding methods include press molding, sheet molding, and cold isostatic pressing (CIP) molding, and press molding is preferred. The pressure in press molding is, for example, 10 kgf / cm. ２ ~500kgf / cm ２ In this way, a molded body having a desired shape is prepared.

[0052] C-3. Firing Step In the firing step, the molded body is fired by any appropriate firing method. Typically, the molded body is fired in a vacuum or a non-oxidizing atmosphere. For example, the temperature is raised from room temperature (23°C) to a predetermined firing temperature, and then the firing temperature is maintained for a predetermined firing time.

[0053] The firing temperature is, for example, 1600° C. to 1900° C., and preferably 1650° C. to 1850° C. The firing time is, for example, 0.5 hours to 20 hours.

[0054] Examples of the sintering method include hot pressing and hot isostatic pressing (HIP), with hot pressing being preferred. In hot pressing, the compact is typically placed in a hot press die (e.g., a graphite die), heated to the sintering temperature as described above, and pressed at a predetermined pressure. The pressure in hot pressing is, for example, 5 MPa to 50 MPa.

[0055] In this manner, a heater for semiconductor manufacturing equipment is manufactured, which includes a ceramic base and a heating element embedded in the ceramic base.

[0056] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these examples. The methods for measuring each property are as follows.

[0057] (1) Measurement of the average linear expansion coefficient of the ceramic base and the heating element The average linear expansion coefficients of the ceramic base and the heating element included in the heaters for semiconductor manufacturing equipment manufactured in the examples and comparative examples were measured in accordance with JIS R 1618. The average linear expansion coefficients of the ceramic base and the heating element and the difference between them are shown in Table 1.

[0058] (2) Measurement of Volume Resistivity of Ceramic Base The volume resistivity of the ceramic base provided in the heater for semiconductor manufacturing equipment manufactured in the examples and comparative examples was measured in accordance with JIS C2141. The results are shown in Table 1.

[0059] <<Example 1>> 95 parts by mass of AlN powder and Y ２ O ３ 3 parts by mass of Yb powder ２ O ３ 1.3 parts by mass of the powder was added to a ball mill and dry-mixed for 10 hours to obtain a mixed powder (raw material mixture). The mixed powder was then granulated by spray drying.

[0060] A coil-shaped heating element made of Mo was also prepared. Next, the mixed powder granules were filled into a predetermined mold, and the heating element was embedded in the desired position. After that, the mixed powder granules filled in the mold were subjected to uniaxial pressing to obtain a disk-shaped compact. The pressure in the uniaxial pressing was 100 kgf / cm. ２ The diameter of the molded body was 350 mm, and the thickness of the molded body was 50 mm.

[0061] The compact was then fired by hot pressing. More specifically, the compact was first placed in a hot pressing die made of graphite and fired at 1850°C for 5 hours by hot pressing. The hot pressing pressure was 10 MPa. A heater for semiconductor manufacturing equipment was thus manufactured, comprising a ceramic substrate and a heating element. The heater for semiconductor manufacturing equipment was then cooled to room temperature (25°C). The ceramic substrate contained Ca and Si as trace elements in addition to AlN, Yb, and Y. The respective content ratios of Y (yttria) and Yb (ytterbium), the total content ratio of rare earth elements, and the content ratios of trace elements, calculated as oxides, are shown in Table 1 below.

[0062] <<Example 2>> Y ２ O ３ The powder was changed to 3.5 parts by mass, and Yb ２ O ３ Except for changing the powder to 0.9 parts by mass, a heater for semiconductor manufacturing equipment was manufactured in the same manner as in Example 1. The respective contents of Y (yttria) and Yb (ytterbium) calculated as oxides, the total content of rare earth elements, and the content of trace components are shown in Table 1 below.

[0063] <<Example 3>> Yb ２ O ３ Except for changing the powder to 0.6 parts by mass, a heater for semiconductor manufacturing equipment was manufactured in the same manner as in Example 1. The respective contents of Y (yttria) and Yb (ytterbium) calculated as oxides, the total content of rare earth elements, and the content of trace components are shown in Table 1 below.

[0064] <<Example 4>> Yb ２ O ３ Except for changing the powder to 0.4 parts by mass, a heater for semiconductor manufacturing equipment was manufactured in the same manner as in Example 1. The respective contents of Y (yttria) and Yb (ytterbium) calculated as oxides, the total content of rare earth elements, and the content of trace components are shown in Table 1 below.

[0065] <<Example 5>> Y ２ O ３ The powder was changed to 2.0 parts by mass, and Yb２ O ３ Except for changing the powder to 0.6 parts by mass, a heater for semiconductor manufacturing equipment was manufactured in the same manner as in Example 1. The respective contents of Y (yttria) and Yb (ytterbium) calculated as oxides, the total content of rare earth elements, and the content of trace components are shown in Table 1 below.

[0066] <<Comparative Example 1>> A mixed powder was prepared by mixing 96 parts by mass of AlN powder and Y ２ O ３ A heater for semiconductor manufacturing equipment was manufactured in the same manner as in Example 1, except that the composition was prepared by mixing 4 parts by mass of the powder with 1 part by mass of the powder. The respective contents of Y (yttria) and Yb (ytterbium) calculated as oxides, the total content of rare earth elements, and the content of trace components are shown in Table 1 below.

[0067] <<Comparative Example 2>> The mixed powder was a mixture of 96 parts by mass of AlN powder and Yb ２ O ３ A heater for semiconductor manufacturing equipment was manufactured in the same manner as in Example 1, except that the composition was prepared by mixing 4 parts by mass of the powder with 1 part by mass of the powder. The respective contents of Y (yttria) and Yb (ytterbium) calculated as oxides, the total content of rare earth elements, and the content of trace components are shown in Table 1 below.

[0068] <<Comparative Example 3>> A mixed powder was prepared by mixing 95 parts by mass of AlN powder and Y ２ O ３ 3.0 parts by mass of powder and Yb ２ O ３ A heater for a semiconductor manufacturing device was manufactured in the same manner as in Example 1, except that the composition was prepared by mixing 0.2 parts by mass of the powder. The respective contents of Y (yttria) and Yb (ytterbium), the total content of rare earth elements, and the content of trace components, calculated as oxides, are shown in Table 1 below.

[0069] <<Comparative Example 4>> A mixed powder was prepared by mixing 96 parts by mass of AlN powder and Y ２ O ３ 2.6 parts by mass of powder and Yb ２ O ３A heater for a semiconductor manufacturing device was manufactured in the same manner as in Example 1, except that 1.5 parts by mass of the powder was mixed with the powder to prepare a heater for a semiconductor manufacturing device. The respective contents of Y (yttria) and Yb (ytterbium) calculated as oxides, the total content of rare earth elements, and the content of trace components are shown in Table 1 below.

[0070] <Evaluation> Table 1 shows the relationship between the volume resistivity of the ceramic base at 500°C. It can be seen that the volume resistivity of the ceramic base can be improved and heaters for semiconductor manufacturing equipment can be stably manufactured. In Comparative Examples 2 and 4, the volume resistivity of the ceramic base is relatively high, but the color unevenness is significant and they are unsuitable for use as products.

[0071] A heater for semiconductor manufacturing equipment according to an embodiment of the present invention is typically used in the manufacture of semiconductors, and can be suitably used in particular as a ceramic heater for holding and heating semiconductor substrates.

[0072] 1 Ceramic base 2 Heating element 100 Heater for semiconductor manufacturing equipment

Claims

1. A heater for semiconductor manufacturing equipment comprising: a ceramic base containing aluminum nitride; and a heating element embedded in said ceramic base, wherein said ceramic base contains two or more rare earth elements, and contains Yb as a rare earth element, the total content of rare earth elements in said ceramic base is 4.5 mass% or less in terms of oxide, and the content of Yb in said ceramic base is 0.3 mass% or more and 1.3 mass% or less in terms of oxide.

2. The volume resistivity of the ceramic substrate at 500°C is 1 x 10 ９ 2. The heater for semiconductor manufacturing equipment according to claim 1, wherein the resistivity is Ω·cm or more.

3. A heater for semiconductor manufacturing equipment according to claim 1 or 2, wherein said ceramic substrate contains Y as said rare earth element.

4. A heater for semiconductor manufacturing equipment according to claim 1 or 2, wherein the content of Ca in the ceramic substrate is 300 ppm or less.

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