JP2018203581A - Ceramic structure - Google Patents

Abstract

To provide a ceramic structure capable of preventing breakage of a ceramic base material caused by thermal expansion of a metallic terminal.SOLUTION: A ceramic structure includes: a ceramic base material 20 with a columnar hole portion 22; a metal electrode layer 30 embedded in the ceramic base material 20; a conductive member 50 that is electrically connected to the metal electrode layer 30 and is embedded in the ceramic base material 20 so as to have an exposed surface 51 where at least portion thereof is exposed from the hole portion 22; a first metallic member 60 that is disposed on the exposed surface 51 of the conductive member 50 and is bonded by a first solder material 70; one or more second metallic members 80 that are disposed on a reverse side of a surface opposed to the exposed surface 51 of the conductive member 50 of the first metallic member 60 and are bonded with the first metallic member 60 by a second solder material 90 having higher ductility than the first solder material 70; and a columnar metallic terminal 40 that is inserted into the hole portion 22 and is bonded with the one or more second metallic members 80 by the second solder material 90.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a ceramic structure.

  By electrically connecting a power supply connector to a metal member such as a metal electrode or a metal resistor embedded in a ceramic substrate such as aluminum nitride, and supplying power to the metal member from the power supply connector, Generation of electric power, heating of the ceramic base material, and the like are performed.

  Such a power supply connector joining structure includes a ceramic base material in which a metal member is embedded and a power supply connector for supplying power to the metal member, wherein at least part of the metal member. A countersunk hole formed in the ceramic substrate so as to be exposed, and a protrusion having a shape that matches the shape of the small-diameter part of the counterbore hole, and the countersunk hole is inserted in the small-diameter part. A stress relieving insert member disposed on the surface, and a brazing material that joins the power supply connector and the stress relieving insert member and seals a gap between the counterbore hole and the stress relieving insert member. Is disclosed (see Patent Document 1).

Japanese Patent No. 4510745

  In Patent Document 1, an active metal foil formed of a metal material such as titanium (Ti) is disposed between a brazing material and a metal member. In such a case, the brazing material becomes stronger in bonding strength with the metal member due to the active metal foil, but has low spreadability.

  Therefore, since the joining of the metal member and the stress relaxation insert becomes stronger, the stress generated by the thermal expansion of the power supply connector (metal terminal) is transmitted to the ceramic substrate via the metal member. As a result, there is a problem that cracks are likely to occur in the ceramic substrate.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a ceramic structure capable of preventing damage to a ceramic base material due to thermal expansion of a metal terminal.

  In order to solve this problem, the ceramic structure of the present invention includes a plate-shaped ceramic base material having a columnar hole extending from the main surface to the inside, a metal electrode layer embedded in the ceramic base material, A conductive member embedded in the ceramic substrate so as to have an exposed surface that is electrically connected to the metal electrode layer and is at least partially exposed from the hole; and on the exposed surface of the conductive member A first metal member that is disposed and joined by a first brazing material, and is disposed on a surface opposite to the surface of the first metal member that faces the exposed surface of the conductive member; and One or a plurality of second metal members joined to the first metal member by a second brazing material having a higher spreadability than the first brazing material; and the one or more second metal members inserted into the hole portion. A second metal member and the second brazing material; It is characterized in that it comprises a columnar metal terminals are joined me.

  According to the ceramic structure of the present invention, the first metal member and the second metal member, and the second metal member and the metal terminal are more expandable than the first brazing material. By joining with the second brazing material, the second brazing material can relieve stress generated in the ceramic base material due to thermal expansion of the metal terminal. For this reason, it becomes possible to prevent a ceramic base material from being damaged by the thermal expansion of the metal terminal.

  In the present invention, the hole has an accommodating portion formed with a smaller diameter than the opening in the main surface of the ceramic base material, and the first metal member is accommodated in the accommodating portion. preferable.

  In the present invention, the first metal member and the second metal member have a pair of surfaces facing each other, and the one metal surface facing each other when viewed from a direction perpendicular to the main surface of the ceramic substrate. Preferably one side of the set includes the other.

  When the surface on the second metal member side includes the surface on the first metal member side, the contact area of the first metal member with the first brazing material is smaller, so the thermal expansion of the metal terminal The generated force, which can be transmitted through the second metal member and the first metal member, can be reduced.

  On the other hand, when the surface on the first metal member side includes the surface on the second metal member side, the contact area of the second metal member with the second brazing material and the metal terminal is reduced. Accordingly, since the force acting on the ceramic base material transmitted from the second metal member to the first metal member caused by the thermal expansion of the metal terminal is also reduced, the ceramic base material can be prevented from being damaged.

  In the present invention, the second brazing material is interposed between the front end surface of the metal terminal in the insertion direction into the hole and the surface of the second metal member facing the front end surface. Is preferred.

  In this case, the second brazing material is a metal terminal by interposing the second brazing material having a higher spreadability than the first brazing material between the second metal member and the surface facing the tip surface. It is possible to maintain the electrical connection while absorbing the deformation due to the thermal expansion.

  In the present invention, it is preferable that a gap is formed from the opening end of the opening of the hole toward the bottom of the hole.

  In this case, by forming a gap from the opening end of the opening of the hole toward the bottom of the hole, the stress generated on the side wall of the hole due to the thermal expansion of the metal terminal can be reduced.

  In this invention, the said metal terminal opposes the said front end surface of the said 2nd metal member distribute | arranged facing the front end surface of the said metal terminal seeing from the direction perpendicular | vertical to the main surface of the said ceramic base material. It is preferable that a concave portion having an opening including the surface is formed on the tip surface.

  In this case, the stress generated toward the ceramic substrate when the metal terminal expands in the axial direction can be more effectively relaxed.

  In the present invention, the first brazing material includes an active metal and one or more kinds of spreadable metals as components, and the second brazing material includes one or more kinds of spreading material. It is preferable to use a metal having ductility as a component. Metals are more easily plastically deformed with increasing purity.

  In this case, the first brazing material is composed of an active metal and a metal having one or more kinds of spreadability as components, thereby strengthening the adhesion of the first metal member to the conductive member. be able to. Moreover, the 2nd brazing material can absorb the deformation | transformation by the thermal expansion of a metal terminal by using the metal which has 1 type, or 2 or more types of ductility as a component.

  In this invention, it is preferable that the said 1st metal member and the said 2nd metal member are comprised with the metal which has a lower thermal expansion coefficient than the said metal terminal.

  In this case, since the first metal member and the second metal member have a lower coefficient of thermal expansion than the metal terminal, the stress generated by the thermal expansion of the metal terminal and transmitted to the ceramic substrate can be reduced.

  In this invention, when it sees from the main surface side of the said ceramic base material, it is preferable that the whole area | region between the said metal terminal and the side wall of the said hole part consists of a said 2nd brazing material.

It is a top view of a ceramic structure. It is the sectional view on the AA line of FIG. 1 is a cross-sectional view showing a ceramic structure according to Example 1. FIG. 6 is a cross-sectional view showing a ceramic structure according to Example 2. FIG. 6 is a cross-sectional view showing a ceramic structure according to Example 3. FIG.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, these may be appropriately modified and combined. In the following description and the accompanying drawings, substantially the same or equivalent parts will be described with the same reference numerals.

  FIG. 1 is a plan view of a ceramic heater 10 according to an embodiment. FIG. 2 is a cross-sectional view taken along line AA in FIG.

As shown in FIG. 1, a ceramic heater 10 as a ceramic structure of the present embodiment has a base material 20 as a plate-like ceramic base material made of, for example, an AIN ceramic sintered body containing Y ₂ O _3. doing.

  The base material 20 has a disk shape. One surface of the base material 20 is a substrate placement surface 20S. As a material of the ceramic sintered body forming the base material 20, it is possible to use silicon nitride, sialon, silicon carbide, boron nitride, alumina, etc. in addition to the above-mentioned aluminum nitride.

  As shown in FIG. 2, the substrate SB (shown by a broken line in FIG. 2) is placed in contact with the substrate placement surface 20S.

  A substrate placement region SR is provided inside a circle centered on the center point C of the substrate placement surface 20S.

The shaft 11 as a support is a cylindrical hollow shaft member. The shaft 11 is made of a ceramic sintered body such as alumina (Al ₂ O ₃ ), aluminum nitride (AlN), or silicon nitride (Si ₃ N ₄ ).

  The shaft 11 is provided with a flange portion 11F at one end portion in the axial direction. The shaft 11 is attached to the lower surface 21 which is the main surface of the base material 20 at one end where the flange portion 11F is formed. For example, the shaft 11 is attached to the base material 20 by solid-phase bonding the lower surface 21 of the base material 20 and the surface of the flange portion 11F.

  The electrode 30 as the metal electrode layer is a heating resistor embedded in the base material 20. The power supply rod 40 as a metal terminal is electrically connected to the electrode 30 at the one end. Further, the power supply rod 40 is connected to a power source (not shown) at the other end. In other words, power from the power source is supplied to the electrode 30 through the power supply rod 40. The electrode 30 is a heating element that generates heat when this electric power is supplied, whereby the entire substrate 20 is heated. Although not shown, a plurality of power supply rods 40 are electrically connected to the electrode 30.

  The electrode 30 is embedded so as to extend over the substrate placement region SR when viewed from a direction perpendicular to the substrate placement surface 20S. The electrode 30 has, for example, a mesh shape when viewed from a direction perpendicular to the substrate placement surface 20S. The electrode 30 is made of a metal material such as molybdenum, for example.

  The power supply rod 40 is formed in a columnar shape that extends in the axial direction of the shaft 11 in the hollow portion of the shaft 11 and that one end portion extends into the base material 20. The power feed rod 40 has a tip surface 41 formed at the tip facing the substrate placement surface 20S.

  As a material for the power supply rod 40, nickel (Ni) or the like can be used. In addition, if the shape of the electric power feeding rod 40 is a column-shaped thing, it can also be made into shapes, such as a polygonal column and a truncated cone, for example.

  A connection mode between the power supply rod 40 and the electrode 30 will be described in detail. FIG. 3 is an enlarged cross-sectional view illustrating a connection mode between the power supply rod 40 and the electrode 30. As shown in FIG. 3, the base material 20 has a columnar hole portion 22 that extends inward from the lower surface 21 toward the substrate placement surface 20 </ b> S.

  Specifically, the hole 22 is formed in a cylindrical shape from the opening 23 toward the substrate placement surface 20S.

  The base material 20 has a constricted portion 25 that protrudes inward in the radial direction of the hole 22 from the inner wall 24 at the upper portion of the inner wall 24 formed by the hole 22 on the substrate mounting surface 20S side. . In other words, the hole 22 is narrower in the upper portion than the opening 23 formed in the lower surface 21 of the base material 20. The constricted portion 25 has an annular plane shape, and the lower surface 21 side of the constricted portion 25 is an annular bottom surface 26.

  On the substrate mounting surface 20S side of the constricted portion 25, a diameter-expanded portion 27 formed so that the diameter of the hole portion 22 extends from the constricted portion 25 is formed.

  A surface 31 arranged on the lower surface 21 side of the base material 20 of the electrode 30 is exposed by the enlarged diameter portion 27.

  The enlarged diameter portion 27 is filled with a conductive member 50. The conductive member 50 is formed on the lower surface 21 side of the base material 20 and partly exposed through a space formed on the inner side of the constricted portion 25 and on the substrate placement surface 20S side. And a surface 52 having a circular shape. In other words, the lower surface of the conductive member 50 is covered with the constricted portion 25 at the periphery, and the exposed surface 51 is exposed downward through the space formed inside the constricted portion 25. As a material of the conductive member 50, a heat-resistant metal such as molybdenum (Mo) or tungsten (W) can be used.

  The conductive member 50 is provided such that the surface 52 is in contact with the surface 31 of the electrode 30. That is, the conductive member 50 and the electrode 30 are electrically connected. The conductive member 50 and the electrode 30 may be electrically connected via a conductor (not shown).

  Further, the constricted portion 25 and the exposed surface 51 of the conductive member 50 form a concave accommodating portion 28 that is recessed from the lower surface 21 side toward the substrate placement surface 20S side. That is, the exposed surface 51 is a surface exposed at the bottom surface of the concave accommodating portion 28.

  A first metal member 60 is provided below the conductive member 50, that is, on the exposed surface 51 of the conductive member 50, spaced from the exposed surface 51. Further, the first metal member 60 is accommodated in the accommodating portion 28.

  Specifically, the first brazing material 70 is filled between the conductive member 50 and the first metal member 60 and between the first metal member 60 and the surface of the constricted portion 25 forming the accommodating portion 28. Has been. In other words, the first brazing material 70 is filled so as to cover the exposed surface 51 of the conductive member 50.

  The exposed surface 51 of the conductive member 50 is exposed to the hole 22 as an electrical connection surface with the first metal member 60.

The first brazing material 70 includes an active metal and a metal having one or more kinds of spreadability as components. Examples of the active metal include titanium (Ti), zirconium (Zr), hafnium (Hf), and the like. Examples of the metal having spreadability include gold (Au), silver (Ag), copper (Cu), and nickel (Ni). Examples of the first brazing material 70 include an Au—Ni—Ti alloy. Note that brazing can be performed at 1100 ° C. in a vacuum furnace. The degree of vacuum in this case can be 1 × 10 ⁻⁴ Pa or less. As described above, when the first brazing material 70 includes the active metal, the bonding between the first metal member 60 and the conductive member 50 can be strengthened.

  Therefore, the first metal member 60 and the conductive member 50 are joined together and electrically connected by the first brazing material 70.

  The first metal member 60 is formed in a disk shape having a surface 61 facing the exposed surface 51 of the conductive member 50 and a surface 62 opposite to the surface 61 and formed on the lower surface 21 side. Has been. In addition, the shape of the 1st metal member 60 is not restricted to disk shape, For example, it may be formed in column shape, prismatic shape, or frustum shape.

  As a material of the first metal member 60, a metal having a lower thermal expansion coefficient than the power supply rod 40, for example, tungsten (W), molybdenum (Mo), koval (registered trademark), or the like may be used. it can.

  A second metal member 80 is provided on the surface 62 of the first metal member 60 so as to face the surface 62.

  The second metal member 80 is formed in a disk shape having a surface 81 facing the first metal member 60 and a surface 82 opposite to the surface 81 and facing the power supply rod 40. Yes. In addition, the shape of the 2nd metal member 80 is not restricted to disk shape, For example, it may be formed in column shape, prismatic shape, or frustum shape.

  As a material of the second metal member 80, a metal having a lower thermal expansion coefficient than that of the power supply rod 40, for example, tungsten (W), molybdenum (Mo), koval (registered trademark), or the like may be used. it can.

  As shown in the figure, in the present embodiment, the second metal member 80 is formed in a disk shape having a diameter larger than that of the first metal member 60.

  Therefore, when viewed from the direction perpendicular to the lower surface 21 of the base material 20, one of the pair of surfaces 81, 62 facing each other, that is, the surface 81 on the second metal member 80 side is the other first metal. A surface 62 on the member 60 side is included.

  The second brazing material 90 is provided between the opposing side walls 24 so as to cover the bottom surface 26 and the surface 62 of the first metal member 60. Therefore, the second brazing material 90 occupies the entire region between the power supply rod 40 and the side wall 24 of the hole 22 when viewed from the lower surface 21 side of the base material 20.

  The second brazing material 90 is provided so as to fill a space between the first metal member 60 and the second metal member 80. Therefore, the first metal member 60 and the second metal member 80 are joined to each other and electrically connected via the second brazing material 90.

  The second brazing material 90 is provided between the distal end surface 41 of the power supply rod 40 and the surface 82 of the second metal member 80 so as to cover the entire second metal member 80. Therefore, the second metal member 80 and the power supply rod 40 inserted into the hole 22 are joined together and electrically connected via the second brazing material 90.

  The second brazing material 90 is provided so as to cover the circumferential direction of the side surface continuous from the distal end surface 41 of the power supply rod 40. Here, the second brazing material 90 does not fill the entire hole 22. That is, a gap 29 is formed from the opening end of the opening 23 of the hole 22 toward the bottom surface 26 of the hole 22.

The second brazing material 90 is composed of a metal having one or more kinds of spreadability. Examples of the metal having spreadability include gold (Au), silver (Ag), copper (Cu), and nickel (Ni). These metals may contain a trace amount of impurities. Therefore, the second brazing material has higher extensibility than the first brazing material 70 because it contains no active metal. In addition, plastic deformation occurs more easily when the purity of the metal increases. An example of the second brazing material 90 containing two or more metals as components is an Au—Ni alloy. The brazing can be performed at 1000 ° C. in a vacuum furnace. In this case, the degree of vacuum can be 1 × 10 ⁻⁴ Pa or less.

  As described above, according to the ceramic heater 10 of the present invention, (1) the first metal member 60 and the second metal member 80 are connected while the conductive member 50 embedded in the substrate 20 and the power supply rod 40 are connected. As described above, by arranging the at least two stress relaxation members so as to overlap each other, the distance between the power supply terminal 40 and the substrate 20 can be physically separated. For this reason, the stress which arises in the base material 20 by the thermal expansion of the feed rod 40 is relieved by the stress relieving member. Thereby, it is possible to prevent the base material 20 from being cracked.

  Here, since the contact area between the first metal member 60 and the first brazing material 70 becomes smaller by forming the diameter of the first metal member 60 smaller, the power supply rod 40 is caused by thermal expansion. The force transmitted to the base material 20 via the second metal member 80 and the first metal member 60 can be reduced.

  From the viewpoint of alleviating the stress generated in the base material 20, the smaller the diameter of the first metal member 60 is, the better. If the first metal member 60 and the second metal member 80 are in point contact, there is almost no stress generated in the base material 20 due to thermal expansion of the power supply rod 40. On the other hand, a cross-sectional area for energizing the first metal member 60 and the second metal member 80 is required. Therefore, the diameter of the first metal member 60 may be determined in consideration of these factors.

  (2) By providing the second metal member 80 between the first metal member 60 and the power supply rod 40, the wettability between the first metal member 60 and the second metal member 80 can be improved. it can. Thereby, even if the 2nd metal member 80 is small diameter, the joint strength of the 1st metal member 60 and the 2nd metal member 80 can be strengthened. In particular, when the material of the second metal member 80 is tungsten, a sufficient current density can be obtained because the volume resistivity is small.

  (3) The second brazing material 90 containing no active metal and the base material 20 are not chemically bonded. Therefore, the stress generated in the base material 20 due to the thermal expansion of the power supply rod 40 generated by brazing with the second brazing material 90 is suppressed, and the occurrence of cracks in the base material 20 can be suppressed.

  (4) The first brazing material 70 is provided so as to cover the conductive member 50 and the first metal member 60, and the second brazing material 90 is composed of the first metal member 60 and the second metal member 80. By being provided so as to cover, it is possible to prevent the oxidation of these members 50, 60, 80, and to extend the life of the ceramic heater 10.

  In particular, when tungsten is used for the conductive member 50, the first metal member 60, and the second metal member 80, the tungsten tends to be oxidized. Tungsten may become brittle by oxidation and cause strength deterioration. For this reason, the power supply rod 40 is dropped or an electrical trouble is caused by a heat cycle load or an external force acting on the power supply rod 40. The first brazing material 70 contains an active metal. For this reason, when the first brazing material 70 is oxidized, the strength is lowered due to the deterioration of wettability, which causes a conduction failure. Therefore, by covering with a second brazing material 90 containing a pure metal brazing material or alloy having high oxidation resistance as a component, the oxidation of tungsten and the oxidation of the first brazing material 70 causing these problems are suppressed. Can do.

  A second brazing material 90 having a higher spreadability than the first brazing material 70 between the first metal member 60 and the second metal member 80 and between the second metal member 80 and the power supply rod 40. The second brazing material 90 relaxes the force acting on the base material 20 caused by the thermal expansion of the power supply rod 40 and maintains electrical connection with each member 40, 60, 80. It becomes possible. For this reason, it becomes possible to prevent the base material 20 from being damaged by the force acting on the base material 20 caused by the thermal expansion of the power supply rod 40.

  Since the first metal member 60 and the second metal member 80 have a thermal expansion coefficient lower than that of the power supply rod 40, the force acting on the base material 20 caused by the thermal expansion of the power supply rod 40 can be reduced.

  By forming the gap 29 from the opening end of the opening portion 23 of the hole portion 22 toward the bottom surface 26 of the hole portion 22, the stress applied to the side wall 24 of the hole portion 22 due to the thermal expansion of the power supply rod 40 can be reduced. it can.

  In the present embodiment, one second metal member 80 is provided. However, a plurality of second metal members 80 may be arranged in the depth direction of the hole 22. Thus, by disposing a plurality of second metal members, it is possible to more effectively relieve stress generated in the base material 20 due to thermal expansion of the power supply rod 40.

  In addition, the second metal member 80 may have a surface facing the first metal member 60 having the same diameter as the first metal member 60.

  Furthermore, the ceramic heater 10 may have a function as an electrostatic chuck that attracts the substrate to the substrate mounting surface 20S by a Coulomb force generated by applying a voltage to the electrode 30.

  In addition, a plurality of electrodes 30 are provided in a direction perpendicular to the substrate placement surface 20S, and the electrode 30 close to the substrate placement surface 20S functions to suck the substrate by Coulomb force, and from the substrate placement surface 20S. The separated electrode 30 may be configured to perform the function of heating the substrate 20 as a heating resistor.

  In the first embodiment, the diameter of the first metal member 60 is the same as that of the second metal member 80 or smaller than that of the second metal member 80. However, the first metal member 60 may be formed larger than the diameter of the second metal member 80. In the first embodiment, the accommodating portion 28 is provided in the hole portion 22. However, you may implement without providing the accommodating part 28. FIG.

  FIG. 4 is an enlarged cross-sectional view illustrating a connection mode between the power supply rod 40 and the electrode 30 of the ceramic heater 10 according to the second embodiment.

  As shown in FIG. 4, the hole 22 is formed in a cylindrical shape from the opening toward the substrate placement surface 20S. A side wall 24 is formed in the radial direction of the hole 22. On the substrate mounting surface 20S side of the hole 22, a diameter-enlarged portion 27 is formed so that the diameter of the hole 22 is increased.

  The enlarged diameter portion 27 is formed so that the surface 31 on which the substrate placement surface 20S side is disposed on the lower surface 21 side of the electrode 30 is exposed. A conductive member 50 is embedded in the base material 20 in the enlarged diameter portion 27.

  A first metal member 60 is provided below the conductive member 50, that is, on the exposed surface 51 of the conductive member 50. Specifically, the first brazing material 70 is filled between the conductive member 50 and the first metal member 60 and between the first metal member 60 and the side wall 24.

  The first metal member 60 is formed larger than the diameter of the second metal member 80. Accordingly, when viewed from the direction perpendicular to the lower surface 21 of the base material 20, one of a pair of surfaces facing each other, that is, the surface 62 on the first metal member 60 side is the other side of the second metal member 80 side. The surface 81 is included.

  Even when configured as described above, the ceramic heater 10 relieves stress generated in the base material 20 due to thermal expansion of the power supply rod 40 and prevents the base material 20 from cracking, as in the first embodiment. The effect of can be produced.

  Further, by forming the second metal member 80 with a small diameter, the contact area of the second metal member 80 with the second brazing material 90 and the power supply rod 40 is reduced. Since the force acting on the base material 20 transmitted from the second metal member 80 to the first metal member 60 due to the thermal expansion of the power supply rod 40 is also reduced, damage to the base material 20 can be prevented.

  FIG. 5 is an enlarged cross-sectional view illustrating a connection mode between the power supply rod 40 and the electrode 30 of the ceramic heater 10 according to the third embodiment.

  As shown in FIG. 5, the power supply rod 40 has a concave portion 42 that is formed to be recessed along the axial direction of the power supply rod 40 on the distal end surface 41.

  The recess 42 includes a surface 82 that faces the distal end surface 41 of the second metal member 80 that is disposed to face the distal end surface 41 of the power supply rod 40 when viewed from the direction perpendicular to the lower surface 21 of the substrate 20. Such an opening.

  The recess 42 is formed such that the depth formed with respect to the axial direction of the power supply rod 40 is shorter than the length of the second metal member 80 in the axial direction of the power supply rod 40.

  The second brazing material 90 is interposed between the tip surface 41 and the surface 82 of the second metal member 80 so as to fill the recess of the recess 42.

  Even when configured as described above, as in the first embodiment, the ceramic heater 10 can exhibit effects such as relaxing the thermal stress acting on the base material 20 and preventing the base material 20 from cracking. it can.

  In addition, since the recess 42 having an opening that includes a surface facing the distal end surface of the second metal member 80 is formed in the distal end surface 41, the second brazing material 90 has the thermal expansion of the power supply rod 40. Thus, the stress generated in the axial direction of the substrate 20 can be more effectively relaxed.

  By forming the recess 42 in this way, it is possible to prevent the front end surface 41 of the power supply rod 40 from directly contacting the surface 82 of the second metal member 80.

  In this embodiment, the recess 42 is formed such that the depth formed with respect to the axial direction of the power supply rod 40 is shorter than the length of the second metal member 80 in the axial direction of the power supply rod 40. did. However, if the feed rod 40 and the second metal member 80 do not directly contact, the depth formed with respect to the axial direction of the feed rod 40 is the axial direction of the feed rod 40 of the second metal member 80. It may be formed longer than the length of.

DESCRIPTION OF SYMBOLS 10 Ceramic heater 20 Base material 21 Lower surface 22 Hole part 23 Opening part 24 Side wall 26 Bottom surface 28 Storage part 29 Gap 30 Electrode 40 Feed rod 41 Tip surface 42 Recessed part 50 Conductive member 51 Exposed surface 60 1st metal member 70 1st row Material 80 Second metal member 90 Second brazing material

Claims (9)

A plate-like ceramic substrate having a columnar hole extending from the main surface to the inside;
A metal electrode layer embedded in the ceramic substrate;
A conductive member embedded in the ceramic substrate so as to have an exposed surface that is electrically connected to the metal electrode layer and is exposed at least partially from the hole;
A first metal member disposed on the exposed surface of the conductive member and joined by a first brazing material;
The first brazing material is disposed on a surface of the first metal member opposite to the surface facing the exposed surface of the conductive member and has a higher spreadability than the first brazing material. One or a plurality of second metal members to be joined to the metal member;
Columnar metal terminals inserted into the holes and joined by the one or more second metal members and the second brazing material,
A ceramic structure comprising: The hole has a receiving portion formed with a smaller diameter than the opening in the main surface of the ceramic substrate;
The ceramic structure according to claim 1, wherein the first metal member is accommodated in the accommodating portion.   The first metal member and the second metal member have a pair of surfaces facing each other, and the pair of surfaces facing each other as viewed from a direction perpendicular to the main surface of the ceramic substrate. The ceramic structure according to claim 1 or 2, wherein one includes the other.   The second brazing material is interposed between a front end surface of the metal terminal in the insertion direction into the hole and a surface facing the front end surface of the second metal member. The ceramic structure according to any one of claims 1 to 3.   The ceramic structure according to any one of claims 1 to 4, wherein a gap 29 is formed from the opening end of the opening of the hole toward the bottom of the hole.   The metal terminal includes a surface facing the tip surface of the second metal member, which is disposed to face the tip surface of the metal terminal when viewed from a direction perpendicular to the main surface of the ceramic substrate. 6. The ceramic structure according to claim 1, wherein a recess having such an opening is formed on the tip surface. The first brazing material includes, as components, an active metal and a metal having one or more kinds of spreadability,
The ceramic structure according to any one of claims 1 to 6, wherein the second brazing material contains a metal having one or more kinds of spreadability as a component.   The ceramic structure according to any one of claims 1 to 7, wherein the first metal member and the second metal member are made of a metal having a lower thermal expansion coefficient than the metal terminal. body.   The whole region between the metal terminal and the side wall of the hole portion is made of the second brazing material when viewed from the main surface side of the ceramic substrate. A ceramic structure according to any one of the above.