JP6208972B2 - Electrode built-in ceramic sintered body and manufacturing method thereof - Google Patents

Description

  The present invention relates to a ceramic sintered body in which one or a plurality of electrodes such as an electrostatic chuck electrode, a heater electrode or a plasma electrode, or a combination thereof used in a semiconductor manufacturing apparatus is incorporated, and a method for manufacturing the same.

  As a method for producing a ceramic sintered body with built-in electrode, a method in which an electrode and another molded body or powder are sequentially stacked on the molded body, and then the molded body or the molded body and the powder are pressure-fired in the stacking direction. Has been proposed (see Patent Documents 1 to 3).

Japanese Patent No. 2766443 Japanese Patent Laid-Open No. 2003-1000042 JP 2003-077995 A

  However, the possibility that the electrode is displaced from the predetermined position when pressure is applied to the molded body is so high that it cannot be ignored. For this reason, the performance derived from the electrode of the ceramic sintered body (heating performance or electrostatic adsorption performance, etc.) deviates from the desired form, and lift pin holes or the like that do not interfere with the electrode are processed into the sintered body. The situation will be difficult.

  Then, an object of this invention is to provide the electrode built-in ceramic sintered compact by which the improvement of the arrangement | positioning precision of an electrode is aimed at, and its manufacturing method.

The electrode built-in ceramic sintered body of the present invention is a ceramic sintered body in which an electrode extending along a plane is built, and the electrode is a metal plate, metal foil, metal mesh or The nail | claw part which is comprised with the metal wire and has the height of 1.0 times or less of the size or thickness of the said electrode about the normal direction of the said plane is provided in the said electrode, It is characterized by the above-mentioned.

  The ceramic sintered body has a mounting surface parallel to the plane for mounting a wafer, and the claw portion is provided so as to extend or protrude from the electrode in the opposite direction to the mounting surface. It is preferable that The electrode extends at least along the plane of the ceramic sintered body with respect to the electrode for generating plasma on the placement surface side or the wafer placed on the placement surface in the ceramic sintered body. And a claw portion having a height not more than 1.0 times the size or thickness of the electrode in the normal direction of the plane. Preferably it is.

  The ceramic sintered body has a mounting surface parallel to the plane for mounting a wafer, and the claw portion is provided so as to extend or protrude from the electrode in the opposite direction to the mounting surface. It is preferable that In order for the electrode to electrostatically attract the electrode for generating plasma on the mounting surface side or the wafer placed on the mounting surface to the ceramic sintered body at least in the ceramic sintered body It is preferable that it is an electrode. It is preferable that the nail | claw part is provided in the edge part of the said electrode. The plurality of claw portions are preferably arranged in different directions or isotropically with respect to the center of the electrode.

The method of the present invention is a method for manufacturing a ceramic sintered body in which an electrode extending along a plane is incorporated, and a plurality of ceramic molded bodies are arranged in a normal direction of the plane so as to sandwich the electrode therebetween. Or embedding the electrode in one ceramic molded body, and firing the plurality of ceramic molded bodies or the one ceramic molded body while pressing them in the normal direction of the plane. The electrode is composed of a metal plate, metal foil, metal mesh or metal wire made of molybdenum or tungsten, and the electrode has a claw portion having a height of 1.0 times or less of the thickness. To do.

  A step of producing the electrode by forming a claw portion by adjusting a shape by processing a metal plate, a metal foil, a metal mesh or a metal wire, and adjusting a height of a burr generated during the processing. It is preferable that it is further included. The ceramic sintered body has a mounting surface parallel to the plane for mounting a wafer, and the claw portion extends or protrudes from the electrode in a direction opposite to the mounting surface. It is preferable to arrange so as to be sandwiched between a plurality of ceramic molded bodies.

  According to the electrode-embedded ceramic sintered body and the method for manufacturing the same according to the present invention, the height of the claw portion provided on the electrode extending along the plane is adjusted to 1.0 times or less the thickness of the electrode. ing. For this reason, it can prevent that a crack or a deformation | transformation arises in a molded object or an electrode at the time of pressurization baking derived from presence of a nail | claw part. In addition, the claw portion can be made to bite into a plurality of molded bodies that are stacked so as to sandwich the electrodes, one molded body in which the electrodes are embedded, or a ceramic sintered body as a result of firing. Thereby, the positional deviation of the electrode is reliably prevented, and the arrangement accuracy is improved.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the electrode built-in ceramic sintered compact as one Embodiment of this invention. FIG. 2 is a configuration explanatory diagram of an electrode built in the ceramic sintered body of FIG. 1. Explanatory drawing regarding the manufacturing method of the ceramic sintered compact of FIG. Explanatory drawing regarding the nail | claw part of an electrode.

(Configuration of ceramic sintered body with built-in electrode)
The electrode-embedded ceramic sintered body 10 (electrode-embedded ceramic part) as an embodiment of the present invention shown in FIG. 1 is a substantially disc-shaped electrostatic chuck with a heater. One of the pair of end surfaces of the ceramic sintered body 10 constitutes a mounting surface 100 on which the wafer is mounted. The ceramic sintered body 10 includes an electrostatic chuck electrode 21 as a “first electrode” and a heater electrode as a “second electrode” that extend along two planes parallel to the mounting surface 100. 22 is built-in.

  The heater electrode 22 is disposed farther from the mounting surface 100 than the electrostatic chuck electrode 21. The perspective relationship between the electrostatic chuck electrode 21 and the heater electrode 22 with respect to the mounting surface 100 may be reversed. Both the electrostatic chuck electrode 21 and the heater electrode 22 are made of a metal plate, a metal foil, a metal mesh, or a metal wire. The metal foil may be punched. Since the electrostatic chuck electrode 21 and the heater electrode 22 experience the firing temperature of the ceramic molded body, a refractory metal is used. For example, when aluminum nitride, alumina, or silicon nitride is used as the ceramic, molybdenum or tungsten is used as the electrodes 21 and 22.

  The number of electrodes incorporated in the ceramic sintered body 10 may be one, or may be three or more. The shape or the like of one or a plurality of electrodes can be appropriately changed according to the purpose of use of the ceramic sintered body 10.

  The electrostatic chuck electrode 21 is formed in a substantially circular shape as shown in FIG. The electrostatic chuck electrode 21 includes four claw portions 212 having a height of 1.0 times or less of the thickness. The four claw portions 212 are arranged approximately isotropic with the center X1 of the electrostatic chuck electrode 21 as a reference. The number and arrangement form of the claw portions 212 are not limited to this, and may be changed to various forms.

  As shown in FIG. 2 (b), the heater electrode 22 is formed in a shape in which a pair of lines extending in a concentric manner while extending outward from one end portion are connected at the other end portion. Has been. The heater electrode 22 includes ten claw portions 222 having a height of 1.0 times or less of the size in the thickness direction or the normal direction of the plane. The ten claw portions 222 are arranged in a plurality of directions with the center X2 of the heater electrode 22 as a reference. The number and arrangement form of the claw portions 222 are not limited to this, and may be changed to various forms.

  As shown in FIG. 1, the claw portion 212 and the claw portion 222 both extend or project downward from the electrostatic chuck electrode 21 and the heater electrode 22 (in the opposite direction to the mounting surface 100). Is provided. As a result, the electrostatic chuck electrode 21 causes the force that causes the wafer placed on the placement surface 100 to be electrostatically attracted to the ceramic sintered body 10 locally from the claw portions 212 or 222. Uniformity is eliminated or reduced. This is the same when the electrode for plasma generation is built in the ceramic sintered body 10 instead of one of the electrodes 21 and 22 or in addition to the electrodes 21 and 22.

  In addition, both the claw portion 212 and the claw portion 222 may be provided so as to protrude upward from each of the electrostatic chuck electrode 21 and the heater electrode 22. The protruding directions of the claw portion 212 and the claw portion 222 may be different. The nail | claw part 212 and the nail | claw part 222 may be arrange | positioned about the normal line direction or the up-down direction of the mounting surface 100 so that it may not overlap.

  In addition to the “outer edge” that extends along the closed curve that includes the electrode inside, the edge of the electrode extends to the inner edge that extends along the closed curve that does not include the electrode inside. "Part". When punching is performed on a metal plate or metal foil, the edge of the punch hole corresponds to the inner edge.

(Method for manufacturing electrode-embedded ceramic sintered body)
(First embodiment)
A first electrode (electrostatic chuck electrode) 21 having a claw portion 212 and a second electrode (heater electrode) 22 having a claw portion 222 are produced. Specifically, a metal plate or the like is processed into a predetermined shape or a design shape by punching or cutting with a blade or a laser (see FIGS. 2A and 2B). During this processing, burrs are generated along the edges of a metal plate or the like having a predetermined shape.

  Since the height of the burr with respect to the plane in which the first electrode 21 and the second electrode 22 extend is uneven, the claw portions 212 and 222 are formed by processing the burr so as to adjust the height. Is done. As a burr processing method, a polishing method or a wet etching method is employed. When the burrs are processed by the wet etching method, the claws 212 and 222 can be formed by raising the tension by bending or striking a predetermined portion.

  The height of the claw portions 212 and 222 is a relationship between the deformability of tungsten or molybdenum constituting the electrodes 21 and 22 and the softness of the molded bodies 31 and 32 to which the claw portions 212 and 222 are bite. Determined by As the density of the molded bodies 31 and 32 is lower, the claw portions 212 and 222 are likely to bite into the molded bodies 31 and 32 (see FIG. 4A).

  The closer the density of the molded bodies 31 and 32 is to the theoretical density (about 65%), the harder, but when the claw portions 212 and 222 are pierced there, the electrodes 21 and 22 are wrinkled or cracked (see FIG. 4B). The height of the claw portions 212 and 222 is determined from the viewpoint that it does not occur or the molded bodies 31 and 32 do not crack. The claws 212 and 222 are preferably low, as long as the goal of preventing displacement of the electrodes 21 and 22 is achieved in a direction parallel to the plane in which the electrodes 21 and 22 extend.

  Assuming that the shape and performance of the electrodes 21 and 22 are not impaired, the electrodes 21 and 22 are punched out with a tool such as a drill or a punch at a place where the electrodes 21 and 22 are removed from the outer edge portion, and burrs generated at that time are processed. Accordingly, a claw portion may be formed on the inner edge portion of the electrodes 21 and 22.

  At least a part of the claw portions may be provided at a position deviated from the edge portions of the electrodes 21 and 22. For example, it is processed so that the location which deviated from the edge of electrodes 21 and 22 may project locally, and the projection concerned may be formed as a claw part. Such a nail | claw part can be formed at the time of rolling of the metal plate etc. which comprise the electrodes 21 and 22. However, from the viewpoint of cost reduction, it is preferable that claw portions are formed at the edge portions of the electrodes 21 and 22, particularly at the outer edge portion.

  As shown on the left side of FIG. 3 (a), the claw portion 212 is located above the substantially disc-shaped molded body 31 (arranged inside the substantially cylindrical fired sheath (not shown)). The electrostatic chuck electrode 21 is placed so as to face. As shown in the center of FIG. 3 (a), a substantially disc-shaped molded body 32 is placed on the electrostatic chuck electrode 21, and the heater electrode 22 is placed so that the claw portion 222 faces upward. Placed. As shown on the right side of FIG. 3A, a substantially disk-shaped molded body 33 is placed on the heater electrode 22.

  The three molded bodies 31 to 33 stacked so as to sandwich the electrostatic chuck electrode 21 and the heater electrode 22 are baked while being pressed in the overlapping direction, whereby the configuration shown in FIG. The ceramic sintered body 10 is obtained. The compacts 31 to 33 are obtained by a general ceramic molding method such as uniaxial press, CIP, casting, or injection molding.

(Second Embodiment)
As shown in the left side of FIG. 3 (b), the claw portion 212 is located above the substantially disc-shaped molded body 31 (arranged inside the substantially cylindrical fired sheath (not shown)). The electrostatic chuck electrode 21 is placed so as to face. Further, the ceramic powder 32 ′ is introduced into the fired sheath so as to cover the electrostatic chuck electrode 21 from above, and the ceramic powder 32 ′ is pressed downward.

  As a result, as shown in the center of FIG. 3B, a new shaped body 63 that is thicker than the shaped body 31 and in which the electrostatic chuck electrode 21 is embedded is formed. The heater electrode 22 is placed on the molded body 32 so that the claw portion 222 faces upward. Further, the ceramic powder 33 ′ is introduced into the fired sheath so as to cover the heater electrode 22 from above, and the ceramic powder 33 ′ is pressed downward.

  As a result, as shown on the right side of FIG. 3B, a new substantially-disc shaped molded body 96 that is thicker than the molded body 63 and in which the electrostatic chuck electrode 21 and the heater electrode 22 are embedded is obtained. It is formed. The molded body 96 is fired while being pressed downward, whereby the ceramic sintered body 10 having the configuration shown in FIG. 1 is obtained.

(Example)
Only 5 wt% of yttrium oxide powder was added to the aluminum nitride powder, and further, a dispersant, a binder and isopropyl alcohol were added, and then mixed using a ball mill. From the mixture, aluminum nitride granules were obtained by spray drying. The granule as a raw material powder was molded by CIP and then raw-processed to produce a substantially disc-shaped molded body of φ320 [mm] × 10 [mm].

  For the electrostatic chuck electrode 21, a molybdenum mesh having a wire diameter of 0.1 [mm] was processed into a predetermined shape using a laser. At this time, the burrs generated at the edges of the molybdenum mesh having a predetermined shape were wet-etched to form the claws 212. For the heater electrode 22, a molybdenum foil having a thickness of 0.1 [mm] was processed into a predetermined shape using a laser. At this time, burrs generated at the edges of the molybdenum mesh having a predetermined shape formed the claw portions 222 by polishing. The height of each of the claw portions 212 and 222 can be measured using an optical microscope.

  Using the molded body and the electrode produced as described above, the electrode-embedded ceramic sintered bodies of Examples 1 and 2 were manufactured according to the method of the first embodiment (see FIG. 3A). Using the granules and the molded body prepared as described above, the electrode built-in ceramics of Examples 3 and 4 were manufactured according to the method of the second embodiment (see FIG. 3B).

  After the upper and lower surfaces of the sintered body 10 of each example were subjected to surface grinding, the relative displacement between the electrostatic chuck electrode 21 and the heater electrode 22 was measured using an X-ray inspection apparatus. The presence or absence of cracks in the claws 212 and 222 was examined. The presence or absence of cracks in the ceramic sintered body 10 in the vicinity of the claw portions 212 and 222 was examined using an ultrasonic flaw detector.

  Table 1 summarizes the measurement results of the characteristics of the sintered bodies of the respective examples.

  Table 1 shows the following. In the ceramic sintered bodies of Examples 1 to 4, the normal direction of the mounting surface 100 is in the range of 0.2 to 0.9 times that is 1.0 times or less the size (thickness) of the electrostatic chuck electrode 21. The height of the claw portion 212 is adjusted so as to be included. The height of the claw portion 222 is adjusted so that it is included in the range of 0.2 to 1.0 times that is 1.0 times or less of the size (thickness) of the electrostatic chuck electrode 22 in the same direction. The relative displacement amount of the electrodes 21 and 22 is in the range of 0.04 to 0.06 [mm]. The electrodes 21 and 22 are not cracked, and the sintered body 10 is not cracked.

(Comparative example)
Using the molded body and electrodes produced in the same manner as in Example 1, the electrode built-in ceramic sintered bodies of Comparative Examples 1 to 4 were manufactured according to the method of the first embodiment (see FIG. 3A). Using the granules and molded bodies prepared in the same manner as in Example 1, the electrode built-in ceramic of Comparative Example 5 was manufactured according to the method of the second embodiment (see FIG. 3B).

  Table 2 summarizes the measurement results of the characteristics of the sintered bodies of the comparative examples.

  Table 2 shows the following. In the ceramic sintered body of Comparative Example 1, the height of the claw portion 212 is 1.4 times larger than 1.0 times the size of the electrostatic chuck electrode 21 in the normal direction of the mounting surface 100. For this reason, when the molded bodies 31 to 33 are pressed in a state of being overlaid, the claw portion 212 excessively bites into the molded body 32 to cause a crack, and as a result, the first electrode 21 (to be exact, In the vicinity of the claw 212), the sintered body 10 is cracked.

  In the ceramic sintered body of Comparative Example 2, the height of the claw portion 222 is 1.2 times larger than 1.0 times the size of the heater electrode 22 in the normal direction of the mounting surface 100. For this reason, when the nail | claw part 222 bites into the molded object 33, the said nail | claw part 222 is loaded and the heater electrode 22 has cracked (refer FIG.4 (b)). Similarly, in the ceramic sintered body of Comparative Example 5, the height of the claw portion 212 is 1.5 times greater than 1.0 times the size of the electrostatic chuck electrode 21 in the normal direction of the mounting surface 100. . For this reason, when the nail | claw part 212 bites into the molded object 32, the said nail | claw part 212 is loaded and the electrostatic chuck electrode 21 is cracked (see FIG. 4B).

  In the ceramic sintered body of Comparative Example 3, there are no claws on each of the electrodes 21 and 22. For this reason, when it pressurizes in the state in which the molded objects 31-33 were piled up, the electrodes 21 and 22 are displaced in the direction parallel to the mounting surface 100, and the relative deviation | shift amount is 0.04-0. It is 1.15 [mm] which greatly exceeds the upper limit of 0.06 [mm].

  In the ceramic sintered body of Comparative Example 4, the electrode 21 has no claw portion. For this reason, when it pressurizes in the state in which the molded objects 31-33 were piled up, the electrode 21 displaces in the direction parallel to the mounting surface 100, and the relative deviation | shift amount is 0.04-0.06. It is 0.78 [mm] which greatly exceeds the upper limit of [mm].

DESCRIPTION OF SYMBOLS 10 ... Ceramic sintered body, 21 ... Electrostatic chuck electrode (1st electrode), 22 ... Heater electrode (2nd electrode), 212 ... Claw part, 222 ... Claw part.

Claims (8)

A ceramic sintered body containing an electrode extending along a plane,
The electrode is composed of a metal plate, metal foil, metal mesh or metal wire made of molybdenum or tungsten,
A ceramic sintered body with a built-in electrode, wherein a claw portion having a height of 1.0 times or less the size or thickness of the electrode is provided on the electrode in the normal direction of the plane. In the electrode-containing ceramic sintered body according to claim 1,
The ceramic sintered body has a mounting surface parallel to the plane for mounting a wafer, and the claw portion is provided so as to extend or protrude from the electrode in the opposite direction to the mounting surface. A ceramic sintered body with a built-in electrode, characterized in that In the electrode built-in ceramic sintered body according to claim 2,
In order for the electrode to electrostatically attract the electrode for generating plasma on the mounting surface side or the wafer placed on the mounting surface to the ceramic sintered body at least in the ceramic sintered body An electrode built-in ceramic sintered body characterized by being an electrode. In the electrode built-in ceramic sintered body according to any one of claims 1 to 3,
The electrode built-in ceramic sintered body, wherein the claw portion is provided at an edge of the electrode. In the electrode built-in ceramic sintered body according to any one of claims 1 to 4,
A ceramic sintered body with a built-in electrode, wherein the plurality of claw portions are arranged in different directions or isotropically with respect to the center of the electrode. A method for producing a ceramic sintered body in which an electrode extending along a plane is incorporated,
Overlaying a plurality of ceramic molded bodies in the normal direction of the plane so as to sandwich the electrodes, or embedding the electrodes in one ceramic molded body,
Firing while pressing the plurality of ceramic molded bodies or the one ceramic molded body in the normal direction of the plane,
The electrode is composed of a metal plate, metal foil, metal mesh or metal wire made of molybdenum or tungsten,
The electrode has a claw portion having a height of 1.0 times or less of the thickness. The method of claim 6 wherein:
A step of producing the electrode by forming a claw portion by adjusting a shape by processing a metal plate, a metal foil, a metal mesh or a metal wire, and adjusting a height of a burr generated during the processing. A method characterized by further comprising: The method according to claim 6 or 7, wherein
The ceramic sintered body has a mounting surface parallel to the plane for mounting a wafer, and the claw portion extends or protrudes from the electrode in a direction opposite to the mounting surface. A method characterized by being arranged to be sandwiched between a plurality of ceramic molded bodies.