JP5189928B2 - Method for producing ceramic member and electrostatic chuck - Google Patents

Description

  The present invention relates to a ceramic member in which a conductive member is embedded, a method for producing the ceramic member, and an electrostatic chuck.

Conventionally, ceramic members such as electrostatic chucks (ESC) and high frequency generating susceptors, in which conductive members such as electrostatic electrodes and resistance heating elements are embedded in ceramics, are used in semiconductor manufacturing apparatuses and liquid crystal manufacturing apparatuses. Such a ceramic member is generally made of aluminum nitride (AlN), alumina (Al ₂ O ₃ ) or the like having excellent heat resistance and corrosion resistance.

Further, it has been proposed to use yttria (Y ₂ O ₃ ) having high corrosion resistance for use in a corrosive gas environment as a ceramic member (see, for example, Patent Documents 1 and 2). Further, a hybrid type ceramic member has been proposed in which yttria is used in a portion exposed to a corrosion-resistant gas and alumina is used in other portions (see, for example, Patent Document 3). Here, the conductive member to be embedded includes refractory metals such as W, Mo, Nb, and the like, and becomes a reference when processing ceramics in the manufacturing process of the ceramic member embedded with the conductive member including these metals. In order to grasp the shape of the conductive member, it was necessary to capture a transmission image with X-rays and grasp the position of the embedded conductive member (hereinafter referred to as “X-ray marking”).

  However, when using a yttria sintered body as a ceramic member, since the yttrium and the embedded metal have similar element numbers, there is a problem in that the position of the embedded conductive member is not known because it has the same transmittance with respect to X-rays. there were. The displacement of the conductive member causes dielectric breakdown at the outer periphery and the hole, but since the yttria sintered body is opaque, it is difficult to confirm the displacement of the conductive member by visual inspection.

  Moreover, as a method of measuring the film thickness of the yttria sintered body, the capacity between the conductive member was measured using a conductive rubber pad, and the film thickness was calculated from the measured value. However, if the conductive rubber pad is small, there is a problem that an error in the measurement value becomes large, so that accurate measurement cannot be performed. Therefore, the diameter of the conductive rubber pad needs to be about 50 mm, and the film thickness can only be obtained as an average value in the measurement region.

When the ceramic member is ESC, in order to measure the temperature of the substrate placed on the ESC, a through hole (opening) that penetrates from the lower surface to the upper surface of the ESC is formed, and the ESC is measured by an optical temperature sensor or the like. The temperature of the substrate was measured from the lower surface side through the opening. However, there is a problem that the optical temperature sensor itself deteriorates because it is exposed to the process gas atmosphere through the opening.
JP 2002-68838 A JP 2002-255647 A JP 2006-128603 A

  An object of the present invention is to provide a ceramic member capable of easily confirming the displacement of a conductive member embedded in the ceramic member, measuring the thickness of the ceramic member, and measuring the temperature of the substrate placed on the ceramic member. To provide a method for producing a ceramic member and an electrostatic chuck.

  According to one aspect of the present invention, (b) a ceramic sintered body having a thermal expansion coefficient equivalent to that of yttria, (b) a conductive member containing a refractory metal, and (c) disposed on the conductive member. There is provided a ceramic member comprising a translucent yttria sintered body, wherein the ceramic sintered body and the yttria sintered body are integrally sintered with the conductive member interposed therebetween.

  According to another aspect of the present invention, (i) a step of mixing a yttria powder having a purity of 99.5% or more with a carbon-containing binder to form a slurry and obtaining granules by a spray granulation method; A step of calcining at 500 to 1000 ° C. in an atmosphere; (c) a step of forming a calcined granule to obtain an yttria molded body; and (d) a yttria molded body at 1400 to 1600 ° C. in a nitrogen atmosphere by hot pressing. A step of firing to obtain an yttria sintered body, (e) a step of forming a conductive member on the yttria sintered body, (f) a step of forming a ceramic formed body on the conductive member, and (g) yttria sintering. The body, the conductive member, and the ceramic molded body were integrally fired in a nitrogen atmosphere by a hot press method at a temperature lower than the firing temperature of the yttria sintered body by 50 ° C., and the yttria sintered body was nitrogenated twice. In creating a ceramic member which comprises a step of sintering is provided.

  According to the present invention, since yttria is translucent, confirmation of displacement of the conductive member embedded in the ceramic member, measurement of the film thickness of the ceramic member, and measurement of the temperature of the substrate placed on the ceramic member It is possible to provide a ceramic member and a method for producing the ceramic member that can be easily performed. In particular, the ceramic member can be suitably used for an electrostatic chuck of a semiconductor manufacturing apparatus.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  Further, the following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the material, shape, structure, The layout is not specified as follows. The technical idea of the present invention can be variously modified within the scope of the claims.

  An electrostatic chuck (ESC) will be described as an example of the ceramic member according to the embodiment of the present invention. As shown in FIGS. 1 and 2, a ceramic member (ESC) 10 according to an embodiment of the present invention is disposed on a ceramic sintered body 12 having a thermal expansion coefficient equivalent to that of yttria, and the ceramic sintered body 12. The conductive member (electrostatic electrode) 15 including the refractory metal embedded therein, the base 11 including the translucent yttria sintered body 13 disposed on the electrostatic electrode 15, and the electrostatic electrode 15 are connected. A connection terminal 14 and an electrode terminal 16 connected to the connection terminal 14 and supplying power are provided. The ceramic sintered body 12 and the yttria sintered body 13 are integrally sintered with the electrostatic electrode 15 interposed therebetween.

  The substrate 11 has an upper surface as a substrate mounting surface for mounting a substrate such as a semiconductor substrate or a liquid crystal substrate. The thickness from the substrate placement surface of the base 11 to the back surface facing the substrate placement surface is preferably 5 mm or less, and more preferably 1 to 3 mm. According to this, the thermal resistance can be reduced, and the thermal characteristics of the ESC 10 can be improved.

  The center line average surface roughness (Ra) of the substrate mounting surface of the base 11 measured by a method according to JISB0601 is preferably 0.6 μm or less, and more preferably 0.4 μm or less. According to this, sufficient adsorption force for adsorbing the substrate can be obtained, and furthermore, generation of particles due to friction between the substrate and the substrate 11 can be suppressed.

  Further, an opening 18 for arranging the connection terminals 14 and the electrode terminals 16 from the lower surface of the ceramic sintered body 12 toward the yttria sintered body 11 and an opening 17 used for measuring the temperature of the substrate are provided. Is formed. The opening 18 reaches one end of the connection terminal 14. The opening 17 penetrates the ceramic sintered body 12 and reaches the lower surface of the yttria sintered body 13.

The yttria sintered body 13 constitutes a portion exposed to corrosive gas. The yttria sintered body 13 is very excellent in corrosion resistance. The yttria sintered body 13 is excellent not only in corrosion resistance against a halogen-based corrosive gas such as nitrogen fluoride (NF ₃ ) but also in corrosion resistance against a plasma corrosive gas. Furthermore, the yttria sintered body 13 has corrosion resistance sufficient to withstand in-situ cleaning in the etching process.

  The yttria sintered body 13 should just comprise the part exposed to at least corrosive gas of ESC10. For example, when the substrate placement surface is exposed to a corrosive gas, at least the substrate placement surface only needs to be composed of the yttria sintered body 13, and the portion other than the substrate placement surface is composed of the yttria sintered body. It does not have to be done. Further, the portion on which the ring member or the like is placed and is not exposed to the corrosive gas may not be formed of the yttria sintered body. Of course, the portion that is not exposed to the corrosive gas may be composed of a yttria sintered body.

  The yttria sintered body 13 is formed on the electrostatic electrode 15 and functions as a dielectric layer of the ESC 10 that uses a Coulomb force as an electrostatic attraction force. The Coulomb force is the electrostatic force generated between the electrostatic electrode 15 and the substrate placed on the dielectric layer (on the substrate placement surface) by applying a voltage to the electrostatic electrode 15. Adsorption power.

In this case, the volume resistivity at room temperature of the yttria sintered body 13 measured by a method according to Japanese Industrial Standard (JIS) C2141 is preferably 1 × 10 ¹⁵ Ω · cm or more, and preferably 1 × 10 ¹⁶ Ω. -More preferably, it is cm or more. Furthermore, the thickness of the yttria sintered body 13 is preferably 0.3 to 0.5 mm, and more preferably 0.3 to 0.4 mm. According to this, high adsorption power can be expressed. Also, the desorption response can be improved.

  The purity of the yttria sintered body 13 is preferably 99.5% or more and the relative density is preferably 99.9% or more. The average particle size of the yttria sintered body 13 is preferably 2 μm or more and 10 μm or less. According to this, the yttria sintered body 13 can obtain high translucency.

The ceramic sintered body 12 having a thermal expansion coefficient equivalent to that of yttria includes alumina, yttria, particle dispersion strengthened yttria, or YAG (3Y ₂ O ₃ .5Al ₂ O ₃ : yttrium aluminum garnet) which is a eutectic of alumina and yttria. ), YAM (2Y ₂ O ₃ .Al ₂ O ₃ ), or YAL (Y ₂ O ₃ .Al ₂ O ₃ ) sintered body is preferably used. This is because these ceramic sintered bodies 12 are insulative and compatible with the yttria sintered body 13 and can be integrated by sintering. Among these, yttria is particularly preferable. This is because if yttria is used, the yttria sintered body 13 of the dielectric layer and the thermal expansion coefficient can be completely matched, so that no warp or the like occurs during the manufacturing process. Further, it is preferable to use a particle dispersion strengthened yttria in which fine powders such as silicon carbide (SiC) and silicon nitride (Si ₃ N ₄ ) are dispersed in Y ₂ O ₃ for the ceramic sintered body 12. According to this, not only the mechanical strength such as bending strength and fracture toughness of the ceramic sintered body 12 can be improved, but also the yttria sintered body 13 and the thermal expansion coefficient are equivalent, so that during the manufacturing process Less likely to warp. Conventionally, yttria sintered bodies have been very brittle and fine chips have occurred during processing, and in particular, drilling has been difficult. However, in the embodiment of the present invention, particle dispersion-strengthened yttria is made of ceramic sintered body 12. By using it, the electrostatic chuck can be easily processed. In particular, by using the particle dispersion-strengthened yttria as a support for the translucent yttria sintered body 13 and providing the opening 18 and the opening 17 in the particle dispersion-strengthened yttria, processing that has been the cause of lowering the yield in the past is currently being performed. Chipping and breakage can be effectively prevented.

  As the electrostatic electrode 15, a high-melting point metal carbide such as WC, NbC, MoC, or TiC, or a printed electrode obtained by screen printing using a mixed powder of these powder and alumina and yttria as a paste, or a high-melting point such as Mo or Nb. It is preferable to use a mesh electrode in which metal is knitted into a fine mesh. By forming the electrostatic electrode 15 with these high melting point materials, it is possible to prevent the electrostatic electrode 15 from melting or reacting with ceramics during the manufacturing process of the ESC 10. It is particularly preferable to use a printed electrode made of a mixed powder of yttria and a refractory metal carbide. Since the yttria powder has the same composition as the yttria sintered body, the conductivity of the electrode can be maintained high without causing a reaction such as eutectic.

  The electrostatic electrode 15 is embedded between the ceramic sintered body 12 and the yttria sintered body 13. According to this, since the electrostatic electrode 15 can be printed after the ceramic sintered body 12 is prepared in advance and a flat surface is provided, the yttria sintered body 13 has a certain thickness as a dielectric layer of the ESC 10. The ESC 10 using the Coulomb force can exhibit a uniform adsorption force. Also, the desorption response can be improved.

The electrostatic electrode 15 preferably has a difference in thermal expansion coefficient between the ceramic sintered body 12 and the yttria sintered body 13 of 3 × 10 ⁻⁶ / K or less. According to this, the adhesion between the electrostatic electrode 15 and the substrate 11 can be improved. Further, it is possible to prevent cracks from occurring in the periphery of the electrostatic electrode 15 of the substrate 11.

  The electrostatic electrode 15 is connected to a connection terminal 14 for making electrical connection to the outside and facilitating the manufacturing process. For the connection terminal 14, a sintered body or metal made of the same material as the electrostatic electrode 15 can be used, and platinum (Pt) or rhodium (Rh) can be used. Since the connection terminal 14 is embedded in the raw material powder of the ceramic sintered body 12 and sintered at the same time, the connection terminal 14 is firmly bonded to the ceramic sintered body 12 and the electrostatic electrode 15. By having the connection terminal 14, it is possible to prevent a hole from being formed in the thin electrostatic electrode 15 when the opening 18 is processed in the ceramic sintered body 12. The connection terminal 14 is joined with an electrode terminal 16 for connection to a power supply member such as a power supply cable for supplying power. The electrode terminal 16 is inserted from the opening 18 of the base body 11. The connection terminal 14 and the electrode terminal 16 are joined by brazing, for example. The connection terminal 14 can be substituted by forming only a substantial portion of the electrostatic electrode 15 thick.

  The ceramic sintered body 12 and the yttria sintered body 13 are close in thermal expansion coefficient and excellent in chemical affinity. Therefore, the ceramic sintered body 12 and the yttria sintered body 13 are firmly joined by sintering. Therefore, the mechanical strength of the ESC 10 can be improved by configuring the base 11 using the ceramic sintered body 12 and the yttria sintered body 13.

In particular, the difference in coefficient of thermal expansion (CTE) between the ceramic sintered body 12 and the yttria sintered body 13 is preferably 0.50 × 10 ⁻⁶ / K or less, and 0.30 × 10 ⁻⁶ / K or less. It is more preferable that it is 0.10 × 10 ⁻⁶ / K or less. The difference in thermal expansion coefficient is the difference in thermal expansion coefficient measured in the temperature range from room temperature to 1200 ° C. According to this, the ceramic sintered body 12 and the yttria sintered body 13 can be more firmly joined by sintering.

  The ceramic sintered body 12, the yttria sintered body 13, and the electrostatic electrode 15 are an integral sintered body. According to this, the ceramic sintered body 12, the yttria sintered body 13, and the electrostatic electrode 15 can be joined more firmly. Furthermore, it is possible to prevent an electrical failure such as arcing, and it is possible to obtain an electrostatic chuck having excellent thermal conductivity and high cooling capacity as compared with the case of integration using an organic adhesive. There are also advantages. In particular, it is preferably sintered into an integrally sintered body by a hot press method.

  As shown in FIG. 3, the ceramic member (ESC) 10 shown in FIGS. 1 and 2 is bonded to a holding member 27 having a cooling function, and is attached in the processing chamber 21 of the plasma etching apparatus. The electrostatic electrode 15 is connected to a high-frequency power source 19 outside the processing chamber 21 via the electrode terminal 16. The substrate 20 is placed on the upper surface of the yttria sintered body 13 and is adsorbed by applying a voltage to the electrostatic electrode 15. A counter electrode 22 is provided so as to face the substrate 20. Etching gas or the like is introduced into the counter electrode 22 from the gas pipe 24. A plurality of gas introduction holes 23 are provided on the surface of the counter electrode 22 facing the substrate. An etching gas is introduced into the processing chamber 21 from the gas introduction hole 23, the substrate 20 is adsorbed by an electrostatic force by a DC power source and a high frequency power source 19 connected to the electrostatic electrode 15, and a counter electrode grounded from the surface of the substrate 20 22 to excite plasma.

  In conventional ceramic members, an yttria sintered body that is opaque to visible light and X-rays is used, so it is difficult to grasp the shape of the electrostatic electrode that serves as a reference for processing embedded in the ceramic member. there were. On the other hand, in the ESC 10 according to the embodiment of the present invention, by using the translucent yttria sintered body 13, the electrostatic electrode 15 embedded through the yttria sintered body 13 can be visually recognized. is there. Therefore, it is possible to confirm the position of the electrostatic electrode 15 and take a reference for processing.

  Further, in the conventional inspection, since yttria is opaque to X-rays, it is difficult to confirm the displacement of the electrostatic electrode in the yttria sintered body. On the other hand, in the ESC 10 according to the embodiment of the present invention, by using the translucent yttria sintered body 13, the outer periphery of the electrostatic electrode 15 and the yttria sintered body 13 and the yttria sintering are used in the optical device. The distance to the hole formed in the body 13 can be accurately measured.

  In addition, as a method of measuring the film thickness of a conventional yttria sintered body, the capacitance between the upper surface of the yttria sintered body and the conductive member (electrostatic electrode) is measured using a conductive rubber pad, and the measured value is measured. From this, the film thickness of the yttria sintered body was calculated. However, if the conductive rubber pad is small, an error in the measured capacitance value becomes large, so that accurate measurement cannot be performed. Accordingly, the diameter of the conductive rubber pad needs to be about 50 mm, and the film thickness can be obtained only by an average value in the measurement region. On the other hand, according to the ESC 10 according to the embodiment of the present invention, since the yttria sintered body 13 is translucent, multi-point measurement in a φ300 mm plane using a thickness measuring device using a laser displacement meter, etc. Thus, the film thickness of the yttria sintered body 13 can be easily measured, and a very accurate film thickness distribution can be obtained.

  Conventionally, in order to measure the temperature of a substrate placed on a ceramic member, a through-hole penetrating from the lower surface to the upper surface of the ceramic member is formed, and the temperature of the substrate is measured through the opening by an optical temperature sensor or the like. However, since the optical temperature sensor itself is exposed to the process gas atmosphere, there has been a problem of deterioration. On the other hand, in the ESC 10 according to the embodiment of the present invention, as shown in FIG. 3, the translucent yttria sintered body is passed through the opening 17 penetrating the ceramic sintered body 12 by the temperature measuring device 25. The temperature of the substrate 20 can be measured via 13. Therefore, since the temperature measuring device 25 is isolated from the process gas atmosphere by the translucent yttria sintered body 13, it is possible to prevent the temperature measuring device 25 from deteriorating. Further, the optical sensor (not shown) can confirm whether the substrate 20 is misaligned or whether the substrate 20 is adsorbed to the yttria sintered body 13 through the opening 17.

  Next, an example of a method for manufacturing the ceramic member (ESC) 10 according to the embodiment of the present invention will be described with reference to FIGS.

  (A) First, an yttria sintered body is formed. The average particle diameter of the raw material yttria powder is preferably 0.1 to 3.5 μm. To a yttria raw material powder having a purity of 99.5% or more, a binder, water, a dispersant and the like are added and mixed to prepare a slurry. As the binder, those which do not easily leave a carbon component by oxidation are good, and examples thereof include polyvinyl alcohol. The dispersant preferably does not contain metal ions. For example, a fatty acid ester dispersant is preferable. Next, the slurry is granulated by spray granulation to obtain granulated granules.

  (B) Next, the granulated granule is calcined at 400 ° C. or higher in an air atmosphere. In this case, it is more preferable to calcine at 500 to 1000 ° C. According to this, since the carbon content of the binder can be completely removed, the yttria sintered body can easily obtain translucency.

(C) Using the calcined granulated granules, a ceramic powder compact (yttria compact) is produced by a mold molding method, a cold isostatic pressure (CIP) molding method, or the like. The yttria molded body preferably has a density of 2 g / cc or less. In the case of liquid phase sintered ceramics, even if cracks occur at the time of temperature rise in the firing step, the cracks can be eliminated in the subsequent liquid phase sintering. On the other hand, in Y ₂ O ₃ sintered by solid phase sintering, when cracks are generated due to shrinkage at the time of temperature rise in the firing process, that is, when cracks occur before solid phase sintering, The crack cannot be eliminated in phase sintering. By setting the density of the yttria molded body to 2 g / cc or less, it is possible to absorb the thermal stress at the time of temperature rise in the firing step, the shrinkage difference between the outer peripheral portion and the central portion, and the like to prevent the occurrence of cracks. As a result, a yttria sintered body free from cracks can be obtained. For example, the density of the yttria molded body can be adjusted to 2 g / cc or less by setting the molding pressure when forming the yttria molded body to 50 kgf / cm ² or less. This is an extremely low molding pressure as compared with a normally used molding pressure of 200 kgf / cm ² . The molding pressure at the time of forming the yttria molded body is more preferably 10 to 50 kg weight / cm ² in that the molded body has a strength that can be handled.

(D) The yttria molded body is placed in a graphite cylinder and upper and lower dies, and fired in a nitrogen gas atmosphere by a hot press method to form an yttria sintered body 13 as shown in FIG. By hot pressing in a nitrogen gas atmosphere, excess oxygen can be removed, and translucency can be easily obtained. The firing temperature of the yttria molded body is preferably 1400 to 1600 ° C. The nitrogen gas purity is preferably 5N or higher. As for the heating rate at the time of firing, when the temperature is 1000 ° C. or less where densification does not start, the temperature is increased to 500 to 1000 ° C./hour for shortening the time, and in the temperature range higher than that, the temperature rising rate is 100 to 300 ° C./hour. It is preferable to warm. Furthermore, the pressure applied is preferably 50~300kg / cm ^2, and more preferably pressurized with 100 to 200 kg / cm ^2. The primary-fired yttria sintered body obtained at this point is poor in translucency.

  (E) Next, as shown in FIG. 5, the electrostatic electrode 15 is formed on the yttria sintered body 13. The surface of the yttria sintered body 13 on which the electrostatic electrode is to be formed is ground to form a smooth surface with a flatness of 10 μm or less. For example, the electrostatic electrode 15 can be formed by printing a printing paste containing electrode material powder (high melting point material powder) on the surface of the yttria sintered body 13 using a screen printing method or the like. Monoterpene alcohol is preferably used as a binder in the printing paste. According to this, the flatness of the electrostatic electrode 15 can be improved, and various shapes of the electrostatic electrode 15 can be easily formed with high accuracy. In this case, it is more preferable to use a printing paste in which alumina powder or yttria powder is mixed with electrode material powder (high melting point material powder). According to this, the thermal expansion coefficients of the electrostatic electrode 15 and the ceramic sintered body and yttria sintered body 13 to be described later can be made closer, and the electrostatic electrode 15 and the ceramic sintered body and yttria sintered body 13 can be made closer to each other. Adhesion with can be improved. Moreover, the thermal contraction rate of the printing paste in the subsequent baking step can be reduced. In this case, the total amount of alumina powder and yttria powder contained in the printing paste is preferably 5 to 30% by mass. According to this, a high adhesion improvement effect can be obtained without affecting the function as the electrostatic electrode 15.

(F) Next, a raw material for the ceramic sintered body is prepared. As the raw material powder, Y ₂ O ₃ powder, Al ₂ O ₃ powder, mixed powder obtained by adding SiC powder, Si ₃ N ₄ powder, etc. to Y ₂ O ₃ powder as a reinforcing agent or sintering aid can be used. . Such a mixed powder can improve mechanical strength such as bending strength and fracture toughness of the ceramic sintered body. A binder, water, a dispersant and the like are added to the raw material powder and mixed to prepare a slurry. An example of the binder is polyvinyl alcohol. The dispersant preferably does not contain metal ions, and examples thereof include fatty acid ester dispersants. The slurry is granulated by spray granulation or the like to obtain granulated granules.

  (G) Next, the granulated granule is calcined at 400 ° C. or higher in a nitrogen atmosphere. In this case, it is more preferable to calcine at 500 to 1000 ° C. According to this, the binder component that causes firing cracks can be removed, and the carbon generated by decomposition of the binder remains in the granulated ceramic granules, so that the atmosphere during firing is slightly reduced. It is thought that it can be.

  (H) A ceramic powder compact is formed on the electrostatic electrode 15. Specifically, a mold having a housing part and a lid part is prepared. The yttria sintered body 13 on which the electrostatic electrode 15 is formed is housed in the housing portion of the mold. Ceramic granulated granules are filled on the yttria sintered body 13 and the electrostatic electrode 15. And it presses from the upper direction of a granulation granule using a cover part, and shape | molds a ceramic molded body by the metal mold | die molding method. At the same time, the yttria sintered body 13, the electrostatic electrode 15, and the ceramic molded body can be integrated.

(I) Next, the yttria sintered body 13, the electrostatic electrode 15, and the ceramic molded body are integrally fired. That is, the yttria sintered body 13, the electrostatic electrode 15, and the ceramic molded body are placed between graphite graphite dies in a graphite cylinder, and fired integrally in an atmosphere of nitrogen at 1.2 atmospheres by a hot press method. As shown in FIG. 6, the ceramic sintered body 12, the electrostatic electrode 15, and the integrally sintered body of the yttria sintered body 13 are sintered and joined. Regarding the temperature increase rate during firing, the temperature is increased from 500 to 1000 ° C./hour to reduce the time at 1000 ° C. or less where densification does not start, and at a temperature increase rate of 100 to 300 ° C./hour in a temperature region higher than that. It is preferable. Furthermore, the pressure applied is preferably 50~300kg / cm ^2, and more preferably pressurized with 100 to 200 kg / cm ^2. The firing temperature is preferably lower by 50 ° C. or more than the firing temperature of the first yttria sintered body 13. The yttria sintered body 13 obtained by firing twice in this way has excellent translucency. Further, since the second firing temperature is lower by 50 ° C. or more, the deformation of the yttria sintered body 13 accompanying the sintering of the ceramic molded body can be suppressed.

  (N) Next, the integrated sintered body is processed to join the electrode terminals 16 to obtain the ESC 10 in which the electrostatic electrode 15 is embedded in the base 11 as shown in FIG. Specifically, the position and depth of the electrostatic electrode 15 embedded from the translucent yttria sintered body 13 side is visually recognized and recorded (scratched). The thickness of the yttria sintered body 13 to be a dielectric layer is adjusted to 0.3 to 0.5 mm by grinding with the scribed position as a reference. Further, the center line average surface roughness (Ra) of the substrate mounting surface is adjusted to 0.6 μm or less by polishing. Further, an opening 18 for inserting the electrode terminal 16 into the ceramic sintered body 12 and an opening 17 for measuring the temperature of the substrate are formed at predetermined positions by drilling. The tip of the opening 17 is preferably as close as possible to the interface between the yttria sintered body 13 and the ceramic sintered body 12 and on the yttria sintered body 13 side. And the electrode terminal 16 is inserted from the opening part 18, and the electrostatic electrode 15 and the electrode terminal 16 are joined by brazing or welding. In this way, the ESC 10 shown in FIGS. 1 and 2 can be obtained.

  (L) In the final inspection, the insulation distance between the electrostatic electrode 15 and the outer periphery of the yttria sintered body 13 and the hole formed in the yttria sintered body 13 can be easily measured visually. In addition, the film thickness of the yttria sintered body 13 can be easily measured by multipoint measurement using a laser, and a very accurate film thickness distribution can be obtained.

  According to the manufacturing method shown in FIGS. 4 to 7, the ESC 10 shown in FIGS. 1 and 2 can be realized.

  Furthermore, by firing integrally using a hot press method, the ceramic sintered body 12 and the translucent yttria sintered body 13 can be joined without using an adhesive or the like, and pores and the like remain at the joining interface. You can avoid it. Therefore, the electrostatic electrode 15 can be completely shielded from the external atmosphere, and the corrosion resistance of the ESC 10 can be improved. Further, the ESC 10 in which the ceramic sintered body 12, the translucent yttria sintered body 13, and the electrostatic electrode 15 are firmly joined can be obtained.

  Further, a dense ceramic sintered body 12 and a translucent yttria sintered body 13 can be obtained, and the withstand voltage can be improved. In particular, it is possible to obtain the yttria sintered body 13 having a high volume resistivity necessary for the ESC 10 using the Coulomb force by sintering the hardly sinterable yttria by a hot press method in a nitrogen atmosphere. It is possible to improve the desorption response and adsorbability.

  99 wt% yttria ceramic sintered body in which 1 wt% silicon carbide fine powder (average particle size 0.3 μm) is dispersed by the above-described production method, WC 85 wt%, yttria 15 wt% electrostatic electrode, and 99.5 An electrostatic chuck having a diameter of about 340 mm and a thickness of 4 mm made of a translucent yttria sintered body of% purity was prepared. The hot press temperature of the primary yttria sintered body was 1500 ° C., the nitrogen atmosphere pressure was 1.2 atm, and the hot press temperature of the entire electrostatic chuck including the electrostatic electrode and the ceramic sintered body was 1450 ° C. After the substrate mounting surface of the sintered body integrated by hot pressing, that is, the surface on the yttria sintered body side is ground with a # 400 diamond grindstone, the electrostatic electrode is passed through the translucent yttria sintered body. The position was confirmed and recorded, and the thickness of the yttria sintered body was measured with a laser film thickness measuring device. Based on these measurement data, the electrostatic chuck is finally processed into a predetermined shape, and the thickness of the dielectric layer (the portion from the electrostatic electrode to the substrate mounting surface) consisting of the translucent yttria sintered body portion is It was set to 0.4 mm.

  On the other hand, as a comparative example, an electrostatic electrode of WC 85 wt% and alumina 15 wt% was formed on an alumina sintered body, an yttria powder was formed, and a fired electrostatic chuck having a diameter of 340 mm was produced. That is, a 1 wt% alumina sintered body (diameter 340 mm, thickness 7 mm) is prepared, an electrostatic electrode of WC 85 wt% and alumina 15 wt% is formed thereon, and a 99.5% purity yttria powder is placed thereon. Molded and hot-press fired at 1500 ° C. Since the yttria sintered body on the substrate mounting surface side was opaque, the exact position of the electrostatic electrode was not known, and a film thickness measuring device using a laser displacement meter was not applicable. The depth of the electrode was measured. Based on these measurement data, the electrostatic chuck was finally processed into a predetermined shape so that the thickness of the dielectric layer was 0.4 mm.

  The adsorption force distributions of the electrostatic chucks of the examples and comparative examples thus obtained were measured at 19 points with a silicon metal probe having a diameter of 5 cm by applying a voltage of 800 V to the electrostatic electrode. The example had an adsorption force of 2210 ± 70 Pa, the comparative example had an adsorption force of 1920 ± 220 Pa, and the example showed a stable adsorption force distribution with very little variation. This is because the position of the electrostatic electrode and the thickness of the dielectric layer are more uniform in the example.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  Although the ESC has been described as an example of the ceramic member 10 according to the embodiment of the present invention, the function and application of the ceramic member 10 are not limited to the ESC. By using the conductive member as an electrostatic electrode, the ceramic member 10 can function as an electrostatic chuck. By using the conductive member as a resistance heating element, the ceramic member 10 can function as a heater. By using an RF electrode as the conductive member, the ceramic member 10 can function as a susceptor. Furthermore, the ceramic member 10 can function as an electrostatic chuck or a susceptor that can be heat-treated by using the conductive member as an electrostatic electrode and a resistance heating element, or an RF electrode and a resistance heating element.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

It is a top view which shows an example of the ceramic member which concerns on embodiment of this invention. It is sectional drawing which shows the AA cross section of FIG. It is the schematic which shows an example which has arrange | positioned the ceramic member which concerns on embodiment of this invention in the plasma processing apparatus. It is process sectional drawing (the 1) which shows an example of the manufacturing method of the ceramic member which concerns on embodiment of this invention. It is process sectional drawing (the 2) which shows an example of the manufacturing method of the ceramic member which concerns on embodiment of this invention. It is process sectional drawing (the 3) which shows an example of the manufacturing method of the ceramic member which concerns on embodiment of this invention. It is process sectional drawing (the 4) which shows an example of the manufacturing method of the ceramic member which concerns on embodiment of this invention.

Explanation of symbols

10 ... Ceramics member (electrostatic chuck)
DESCRIPTION OF SYMBOLS 11 ... Base | substrate 12 ... Ceramic sintered compact 13 ... Yttria sintered compact 14 ... Tablet 15 ... Conductive member (electrostatic electrode)
DESCRIPTION OF SYMBOLS 16 ... Electrode terminal 17 ... Opening part 18 ... Opening part 19 ... High frequency power supply 20 ... Substrate 21 ... Processing chamber 22 ... Counter electrode 23 ... Gas introduction hole 24 ... Gas piping 25 ... Temperature measuring instrument 27 ... Holding member

Claims (2)

A ceramic sintered body having a thermal expansion coefficient equivalent to that of yttria;
A conductive member containing a refractory metal;
A translucent yttria sintered body disposed on the conductive member,
The ceramic sintered body and the yttria sintered body are integrally sintered across the conductive member ,
The ceramic sintered body is made of yttria or yttria in which fine particles of silicon carbide or silicon nitride are dispersed,
The conductive member is a printed electrode made of a mixture of tungsten carbide powder and yttria powder,
The translucent yttria sintered body has a purity of 99.5% or more.
Electrostatic chuck . Mixing a carbon-containing binder with yttria powder having a purity of 99.5% or more to form a slurry, and obtaining granules by spray granulation;
Calcining the granules at 500 to 1000 ° C. in an air atmosphere;
Molding the calcined granule to obtain a yttria molded body;
Firing the yttria molded body in a nitrogen atmosphere at 1400 to 1600 ° C. by a hot press method to obtain an yttria sintered body;
Forming a conductive member on the yttria sintered body;
Forming a ceramic molded body on the conductive member;
The yttria sintered body, the conductive member and the ceramic molded body are integrally fired in a nitrogen atmosphere by a hot press method at a temperature lower by 50 ° C. than the firing temperature of the yttria sintered body, and the yttria sintered body A process for imparting translucency to a ceramic member.

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