JP2019208006A - Manufacturing method of electrode embedding member - Google Patents

Abstract

To provide a manufacturing method of an electrode embedding member, capable of suppressing trouble occurrence of a crack of a substrate.SOLUTION: A manufacturing method of an electrode embedding member 1, includes: a preparation step of preparing a metal compact 4a as a connection member 4 by pressing and molding a powder material containing a plurality of metal particles; a ceramic body manufacturing step of manufacturing a ceramic body 2c in which an inner electrode 3 and the metal compact 4a are embedded; and a substrate manufacturing step of manufacturing a substrate 2 in which the connection member 4 having a space free of metal in an inner part is embedded by burning the ceramic body 2c in which the inner electrode 3 and the metal compact 4a are embedded.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of manufacturing an electrode embedding member in which an internal electrode is embedded in a plate-like base material made of ceramics.

  Conventionally, an electrode embedding member in which an internal electrode is embedded in a plate-like base material made of ceramics is known. In the electrode embedding member, when the insertion hole for connecting the terminal to the internal electrode is drilled in the base material, the connection member is previously arranged at a position where the internal electrode and the terminal are connected so as not to damage the internal electrode. In addition, it is necessary to take measures such as preventing the internal electrode from being damaged by the connecting member. As such an electrode embedding member in which the internal electrode is embedded, an electrode embedding member in which a connection member for connecting a terminal to the internal electrode embedded in the ceramic substrate has been proposed (for example, Patent Documents). 1).

JP 2010-34514 A

  However, in the member by the manufacturing method disclosed in Patent Document 1, the coefficient of thermal expansion between the base material and the connecting member due to the influence of heat during the manufacturing process such as brazing and repeated temperature changes during use. Due to the difference, the base material was cracked, and the insulating performance of the base material could not be ensured.

  An object of this invention is to provide the manufacturing method of the electrode embedding member which can suppress the malfunction of the crack of a base material in view of the above point.

[1] In order to achieve the above object, the method for producing an electrode embedding member of the present invention comprises:
A plate-like substrate having a front surface and a back surface and made of ceramics;
An internal electrode extending along the surface of the substrate and embedded in the substrate;
A connecting member disposed over the internal electrode;
A terminal hole drilled from the back surface of the base material to the end face of the connection member inside the base material;
A terminal disposed in the terminal hole and connected to the connection member;
A method of manufacturing an electrode embedding member comprising:
A preparatory step of preparing a metal molded body to be the connection member by pressure-forming a powder raw material containing a plurality of metal particles;
A ceramic body manufacturing step of manufacturing a ceramic body in which the internal electrode and the metal molded body are embedded;
A base material preparation step for preparing the base material in which the connection member having a space in which no metal exists is embedded by firing the ceramic body in which the internal electrode and the metal molded body are embedded;
It is characterized by having.

[2] Moreover, the manufacturing method of the electrode embedding member of the other aspect of the present invention includes:
A plate-like substrate having a front surface and a back surface and made of ceramics;
An internal electrode extending along the surface of the substrate and embedded in the substrate;
A connecting member disposed over the internal electrode;
A terminal hole drilled from the back surface of the substrate to the end surface of the substrate inside the substrate;
A terminal disposed in the terminal hole and connected to the connection member;
A method of manufacturing an electrode embedding member comprising:
A preparatory step of preparing a metal calcined body that becomes the connecting member by calcining a metal molded body obtained by pressure forming a powder raw material containing a plurality of metal particles;
A ceramic body manufacturing step of manufacturing a ceramic body in which the internal electrode and the metal calcined body are embedded;
A base material preparation step for preparing the base material in which the connection member having a space in which no metal exists is embedded by firing the ceramic body in which the internal electrode and the metal calcined body are embedded;
It is characterized by having.

According to such a manufacturing method, a metal molded body or a metal calcined body can be manufactured in advance, so that the form (particle size, pores) of the porous connection member formed by firing the metal molded body or the metal calcined body Sintering structure of metal particles such as rate and average pore diameter) and other components can be included in the metal molded body or metal calcined body to adjust the adhesion and thermal expansion coefficient between the connecting member and the substrate. As a result, it is possible to suppress cracks in the base material when receiving heat during the manufacturing process such as brazing and hot pressing, and when receiving heat from the heat cycle during use of the electrode embedding member. It becomes easy.
Furthermore, it is possible to manufacture an electrode embedding member in which deterioration of electrical characteristics such as conductivity is suppressed by appropriately sintering the metal particles and the metal particles of the metal molded body.
Furthermore, the ceramic which comprises a base material penetrate | invades into the space (open hole) of a connection member, and the electrode embedding member which the adhesive force of a connection member and a base material improved more can be manufactured.

  [3] Moreover, in the electrode embedding member of the present invention, it is preferable that in the preparation step, the powder raw material is prepared by mixing at least two types of metal particles having different particle sizes.

  By this process, the sinterability of the metal molded body can be adjusted, and a space (open pores) is formed by a metal having a large particle size and is densified to some extent by a metal having a small particle size to contain two kinds of metal particles. Makes it easier to adjust the adhesion to the substrate and the coefficient of thermal expansion. As a result, when receiving heat during the manufacturing process such as brazing and hot pressing, and receiving heat from the heat cycle during use In some cases, cracks in the substrate can be further suppressed.

  [4] In the electrode embedding member of the present invention, the preparation step of preparing the metal molded body or the metal calcined body uses one or more types of the metal particles in the metal molded body, The metal particles preferably have a particle size of 1 to 150 μm and a volume ratio of 80 to 100% in all types of the metal particles.

  By this step, even if the electrode-embedded member is used under more severe conditions such as a large temperature difference, cracks can be suppressed from entering the base material.

It is explanatory drawing which shows the electrode embedding member of this invention typically. It is explanatory drawing which shows the preparation methods of the electrode embedding member of this invention. It is explanatory drawing which shows the state of the metal particle before hot press baking. It is explanatory drawing which shows the state of the metal particle after hot press baking.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, drawing shall show the electrode embedding member 1 notionally (schematically).

As shown in FIG. 1, the electrode embedding member 1 has a front surface 2a and a back surface 2b, and includes aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AlN), nitrogen carbide (SiC), and silicon nitride (Si ₃ N _4). ) And the like, a plate-like base material 2 made of ceramics, an internal electrode 3 extending in parallel with the surface 2a of the base material 2 and embedded in the base material 2, and a disk shape along the surface 2a of the base material 2 And a connecting member 4 disposed so as to overlap the internal electrode 3 extending in the direction.

  A terminal hole 5 is formed in the base material 2 so as to be drilled from the back surface 2 b of the base material 2 to the end surface of the connection member 4 inside the base material 2. The electrode embedding member 1 includes a rod-shaped terminal 7 that is disposed in the terminal hole 5 and connected to the connection member 4 via a disk-shaped buffer member 6. The buffer member 6 and the terminal 7 are joined to the connection member 4 by brazing or the like.

  The internal electrode 3 and the connection member 4 are made of tungsten, molybdenum, or an alloy containing these as main components. The terminal 5 has a columnar shape and is made of a low thermal expansion metal alloy such as Kovar, nickel, titanium, copper, or an alloy containing these as a main component, and is joined to the connection member 4 by brazing and electrically connected to the connection member 4. It is connected.

  The diameter of the terminal hole 5 is 5 mm. The terminal 7 has a diameter of 4.8 mm and a length of 20 mm. A gap 12 is formed between the terminal 7 and the inner surface 11 of the substrate 2 that defines the terminal hole 5. The width of the gap 12 is 0.1 mm.

  Next, the manufacturing method of the electrode embedding member 1 is demonstrated. The manufacturing method of the electrode embedding member 1 includes a preparation process for preparing the metal molded body 4a or the metal calcined body, a ceramic body manufacturing process for manufacturing the ceramic body 2c, and a base material manufacturing process for manufacturing the base material 2. Including at least. In addition, you may implement the process of preparing the powder raw material 15 by mixing at least 2 types of metal particles 14a and 14b from which a particle size differs before the process of preparing the metal forming body 4a or a metal calcined body.

[Step of preparing powder raw material 15]
As shown in FIGS. 2A and 3, in the step of preparing the powder raw material 15, the powder raw material 15 is obtained by mixing at least two types of metal particles 14 a and 14 b having different particle sizes. In the embodiment, the powder raw material 15 is a mixture of two types of metal particles 14a and 14b. However, the present invention is not limited to this, and a mode in which only one type of metal particle 14 is used and three or more types of metal particles 14 are mixed. It is good also as a form to do.

[Preparation process for preparing the metal molded body 4a or the metal calcined body]
As shown in FIG. 2A, the step of preparing the metal molded body 4a obtains the metal molded body 4a to be the connection member 4 by press-molding the powder raw material 15 including the plurality of metal particles 14 shown in FIG.

  Specifically, the powder raw material 15 in which the binder 16 is added to the plurality of metal particles 14 shown in FIG. 3 is pressure-molded with a uniaxial press die, whereby the diameter of the connection member 4 (see FIG. 2D) is 10 mm, A disk-shaped metal molded body 4a having a thickness of 0.5 mm is obtained. The metal particles 14 include first metal particles 14a and second metal particles 14b having different particle sizes. In addition, you may perform the degreasing process which degreases the metal mold body 4a in the temperature range of 200 to 600 degreeC by air | atmosphere atmosphere or nitrogen atmosphere in order to remove the binder 16. FIG.

In the embodiment, the metal molded body 4a is only pressure-molded. However, the metal molded body 4a is temporarily fired in a nitrogen, argon, or vacuum atmosphere furnace, for example, at a temperature of 1000 ° C. or higher and 1800 ° C. or lower. The metal molded body 4a can be used as a calcined body. This corresponds to a preparation step of preparing a metal calcined body to be a connection member by calcining a metal molded body obtained by pressure-molding a powder raw material containing a plurality of metal particles.
In this preparation step, the outer diameter and thickness of the metal calcined body may be adjusted by grinding or polishing.

[Ceramic body manufacturing process for manufacturing ceramic body 2c]
As shown in FIG. 2B, the step of producing the ceramic body 2c obtains the ceramic body 2c in which the internal electrode 3 and the metal molded body 4a are embedded.

  Specifically, an insulating layer is formed. A powder mixture composed of 95% by mass of aluminum nitride powder and 5% by mass of yttrium oxide powder was obtained, filled in a mold, and subjected to uniaxial pressure treatment. As a result, a first layer (insulating layer) having a diameter of 340 mm and a thickness of 5 mm was formed.

  Next, the internal electrode 3 is installed. On the first layer, a 290 mm diameter molybdenum foil (thickness: 0.1 mm) serving as the internal electrode 3 was placed. On the internal electrode 3, a disk-shaped metal molded body 4a or a metal calcined body made of tungsten, having a diameter of 10 mm and a thickness of 0.5 mm is placed. The metal molded body 4 a or the metal calcined body was provided at 20 locations on one base material 2. When connecting the metal molded body 4a or the metal calcined body to the internal electrode 3, a conductive member such as tungsten paste is applied to the portion of the internal electrode 3 on which the metal molded body 4a or the metal calcined body is to be stacked.

  Next, the second layer is formed. A ceramic powder is filled on the first layer so as to cover the internal electrode 3 and the metal molded body 4a or the metal calcined body, and uniaxial pressure treatment is performed to form a second layer molded body.

  Next, a heater electrode is installed. A heating resistor made of a molybdenum mesh (wire diameter: 0.1 mm, mesh opening: 50 mesh) formed in a predetermined pattern for the purpose of heating the electrode embedding member 1 itself as a wafer holding device is arranged, and a predetermined heater terminal is arranged. A connecting member for heater terminals (tungsten pellet, diameter 10 mm, thickness 0.5 mm) is placed on the connection position.

  Next, a molded body before firing is formed. A ceramic powder is filled on the heater electrode, and the third layer is formed by uniaxial pressure treatment.

[Substrate production process for producing substrate 2]
The process of producing the base material 2 includes a connection 17 having a space 17 (see FIG. 4) in which no metal is present by firing the ceramic body 2c in which the internal electrode 3 and the metal molded body 4a or the metal calcined body are embedded. The base material 2 in which the member 4 is embedded is obtained. The metal molded body 4a or the metal calcined body becomes the connection member 4 by being fired.
In detail, a baking process is implemented. In the firing step, the laminated body laminated up to the third layer was subjected to hot press firing at a pressure of 10 MPa at a firing temperature of 1800 ° C. and a firing time of 2 hours to obtain a ceramic sintered body having a diameter of 340 mm and a thickness of 20 mm.

  Next, a processing step after firing is performed. As shown in FIG. 2C, in the processing step after firing, the outer surface of the ceramic sintered body is ground and polished, and a wafer mounting surface (surface) with a distance of 0.3 mm from the internal electrode 3 and a surface roughness Ra of 0.4 μm. 2a) was formed.

  Next, the terminal 7 is connected. Drilling processing (diameter 5 mm) is performed so as to reach the connection member 4 from the back surface 2b of the ceramic substrate after firing to form the cylindrical terminal hole 5 reaching the connection member 4 from the back surface 2b. . A Kovar cushioning member 6 having a diameter of 4.8 mm and a thickness of 2 mm is disposed on the connection member 4 defining the terminal hole 5 via an Au—Ni brazing material. Next, a cylindrical nickel power supply terminal 7 having a diameter of 4.8 mm and a length of 200 mm is disposed on the buffer member 6 via a brazing material obtained by adding Ti as an active metal to Au—Ni. Then, brazing was performed by heating at 1050 ° C. in a vacuum furnace, and the electrode embedding member 1 was completed.

Note that Ti may be added as an active metal to the brazing material, and an Ag-based brazing material can also be used.

Next, the effect of the manufacturing method of the electrode embedding member 1 described above will be described.
According to this manufacturing method, since the metal molded body 4a (or the metal calcined body) can be manufactured in advance, the form of the porous connection member 4 formed by firing the metal molded body 4a or the metal calcined body. (Sintered structure of metal particles such as particle diameter, porosity, average pore diameter, etc.) and the adhesion between the connecting member 4 and the substrate 2 by incorporating another component into the metal molded body 4a or the metal calcined body And the thermal expansion coefficient can be adjusted, and as a result, when receiving heat during the manufacturing process such as brazing and hot pressing, and when receiving heat from the heat cycle when the electrode-embedded member 1 is used. It becomes easy to suppress the crack of the base material 2.

  Furthermore, the electrode embedding member 1 in which a decrease in electrical characteristics such as conductivity is suppressed can be manufactured by appropriately sintering the metal particles 14 and the metal particles 14 of the metal molded body 4a.

  Furthermore, the ceramic which comprises the base material 2 penetrate | invades in the space 17 (open hole) of the connection member 4, and the electrode embedding member 1 which the adhesive force of the connection member 4 and the base material 2 improved more can be manufactured.

  By including a step of preparing a powder raw material 15 for mixing at least two types of metal particles 14a and 14b having different particle sizes, the adhesion and thermal expansion with the substrate 2 can be achieved by including the two types of metal particles 14a and 14b. The coefficient can be adjusted more easily. As a result, cracks in the base material 2 are further suppressed when receiving heat during the manufacturing process such as brazing and hot pressing, and when receiving heat from the heat cycle during use. Can do.

Next, the connection member 4 will be described.
As shown in FIG. 4, the connection member 4 is a state in which the metal particles 14 (see FIG. 3) and the metal particles 14 are partially sintered, and the metal particles 14 are so-called necked and sintered, A space 17 in which no metal (metal particles 14) is present is formed inside.

  Normally, when the metal particles 14 are sintered, the necking portion grows and densification progresses. In order to suppress the densification, the present invention uses coarse particles for the metal particles 14 so that a space is formed inside even during sintering. 17 is formed.

  For this reason, the connection member 4 can be made into a porous structure composed of the metal particles 14. By making the porous body, the difference in expansion coefficient and shrinkage ratio induced by the difference in the physical properties of the ceramics composing the connecting member 4 and the base material 2 can be suppressed, and as a result, between sintering and brazing. It is possible to suppress the stress acting on the substrate 2 and to suppress problems such as cracks in the base material 2 and cracks in the connection member 2.

  Next, the connection member 4 produced by changing the particle size and the mixing ratio of the metal particles 14 was used to evaluate the electrode embedding member 1.

  As an evaluation method, after heating the produced electrode embedding member 1 to 600 ° C. and repeating a thermal cycle of cooling to room temperature 10 times, the presence or absence of cracks was visually confirmed. Then, the tensile test of the terminal 7 was done and the presence or absence of the generation | occurrence | production of a crack was confirmed by scanning electron microscope observation (SEM observation) of the cross section of the electrode embedding member 1. Count the number of places where cracks occurred on the surface 2a side of the base material 2 immediately above the terminals 7, and evaluate that 0 out of 20 of the connection members 4 are suitable, and those having one or more cracks It was evaluated as inappropriate.

  In the first to fifth embodiments, the first metal particles 14a are made of tungsten coarse particles, the second metal particles 14b are made of tungsten powder, and their respective particle sizes and mixing ratios (volume mixing ratios) are changed. The molded body 4a is produced and used as the electrode embedding member 1 by the above manufacturing method.

  In Example 6, after forming the metal molded body 4a using only the first metal particles 14a that are coarse particles of tungsten, the metal molded body 4a was calcined under conditions of nitrogen atmosphere and 1500 ° C., and the diameter was 10 mm. The electrode embedding member 1 is manufactured by a method similar to the above manufacturing method except that a metal calcined body processed into a disk shape having a thickness of 0.5 mm is used instead of the metal molded body 4a of Examples 1 to 5. It is a thing.

  In Comparative Example 1, the electrode embedding member 1 was formed by the above-described manufacturing method except that a pellet made of disk-shaped tungsten having a diameter of 10 mm and a thickness of 0.5 mm was used instead of the metal molded body 4a.

  For the measurement of particle size, for raw material powders (metal particles 14a and 14b), a general particle size distribution measuring device (laser analysis method, gravity sedimentation method), scanning electron microscope observation (SEM observation), particle size gauge, etc. are used. And confirm. Moreover, in Table 1, although the range of the particle size of the first metal particle 14a and the second metal particle 14b is described, d90 obtained by the cumulative distribution of the particle size is an upper limit value of this range, and d10 is a lower limit of the range. The median value in this range was the representative particle size. Moreover, in the electrode embedding member 1, it confirms by the SEM observation of the cross section.

  The table below shows the above evaluation results.

  As a result, in Examples 1 to 4, it was found that the number of crack occurrences was 0 and the reliability was high. In Example 5, the number of cracks was one, and it was found that the reliability was low compared to Examples 1-4. This is because the tungsten particle diameter is 0.6 to 1 μm, the sintering of the tungsten particles proceeds, and after firing, it looks like a bulk body, and the tungsten is sintered too densely. 4, it is estimated that cracks were generated due to the stress due to the difference in thermal expansion coefficient.

  In Example 6, it was found that the number of cracks was zero and the reliability was high. This is because the representative particle size of the first metal particles was slightly larger than that of Example 5, and a space in which no metal was present was prepared in advance in the connection member 4 by embedding a metal calcined body. This is presumably because the effect of mitigating the stress induced around the connection member 4 has hardened.

  Comparative Example 1 was an example applied to a conventional electrode embedding member, and the number of cracks was 4 and it was found that the reliability was extremely low and impractical. This is because the structure of the tungsten constituting the pellet was excessively grain-grown by the firing temperature of 1800 degrees, so that the strength of the pellet was reduced, the pellet itself was cracked, and between the substrate 2 and the connecting member 4 It is presumed that cracks were generated by the stress due to the difference in thermal expansion coefficient.

  Thus, the preparatory process of preparing the metal molded body 4a or the metal calcined body uses one or more types of metal particles 14a in the metal molded body 4a, and the particle size of one type of metal particles 14a is 1 to 1. 150 μm, and the mixing ratio (volume ratio of all kinds of metal particles 14) is 80 to 100%, so that the electrode-embedded member 1 can be used under more severe conditions such as a large temperature difference, It can suppress that the base material 2 enters a crack.

  In addition, since the so-called green sheet laminated product generally forms electrodes by printing, the particle diameter of tungsten is adjusted to 1 μm or less, so the particle diameter is small and easy to sinter. Further, the outer edge portion of the electrode is thinned by printing to become an acute angle. Therefore, the sintered structure is integrated (densified) because the original particle diameter is not known, and stress is easily generated at the outer edge of the electrode.

  On the other hand, a granule having a relatively large particle size (a granule having a particle size larger than that of the tungsten paste of the green sheet laminate product) requires a larger particle size and a higher sintering temperature. As a result of the state change hardly progressing to (densification), the structure becomes porous (particles are necked and partially sintered). Moreover, the thickness and the external shape of the metal molded body 4a or the metal calcined body to be the connection member 4 can be adjusted by machining the metal molded body 4a or the metal calcined body to be the connecting member 4, and after firing. The stress concentration in the connecting member 4 can be suppressed.

  In the embodiment, the connection member 4 and the buffer member 6 are bulk bodies made of tungsten, molybdenum, or an alloy containing these as a main component. However, the present invention is not limited to this, and the average linear expansion coefficient is smaller than that of the terminal 7. If other materials are used, other general materials can be used.

  In the embodiment, the width of the gap 12 is 0.1 mm. However, the present invention is not limited to this, and the gap 12 may have a width of 0.01 mm, 0.05 mm, 0.2 mm, or the like. Furthermore, it does not matter even if the terminal 7 contacts the terminal hole 5 and the gap is zero. Moreover, the diameter of the terminal 7 may be changed to other values such as 4.6 mm and 5 mm, and the diameter of the terminal hole 5 may be changed to other values such as 4.9 mm and 5.1 mm.

DESCRIPTION OF SYMBOLS 1 ... Electrode embedding member 2 ... Base material 2c ... Ceramic body 3 ... Internal electrode 4 ... Connection member 4a ... Metal molding 5 ... Terminal hole 7 ... Terminal 14 ... Metal particle 14a ... 1st metal particle (coarse particle)
14b ... 2nd metal particle (powder)
17 ... Space

Claims (4)

A plate-like substrate having a front surface and a back surface and made of ceramics;
An internal electrode extending along the surface of the substrate and embedded in the substrate;
A connecting member disposed over the internal electrode;
A terminal hole drilled from the back surface of the base material to the end face of the connection member inside the base material;
A terminal disposed in the terminal hole and connected to the connection member;
A method of manufacturing an electrode embedding member comprising:
A preparatory step of preparing a metal molded body to be the connection member by pressure-forming a powder raw material containing a plurality of metal particles;
A ceramic body manufacturing step of manufacturing a ceramic body in which the internal electrode and the metal molded body are embedded;
A base material preparation step of preparing the base material in which the connection member having a space in which no metal exists therein is embedded by firing the ceramic body in which the internal electrode and the metal molded body are embedded;
A method for producing an electrode embedding member comprising: A plate-like substrate having a front surface and a back surface and made of ceramics;
An internal electrode extending along the surface of the substrate and embedded in the substrate;
A connecting member disposed over the internal electrode;
A terminal hole drilled from the back surface of the substrate to the end surface of the substrate inside the substrate;
A terminal disposed in the terminal hole and connected to the connection member;
A method of manufacturing an electrode embedding member comprising:
A preparatory step of preparing a metal calcined body that becomes the connecting member by calcining a metal molded body obtained by pressure forming a powder raw material containing a plurality of metal particles;
A ceramic body manufacturing step of manufacturing a ceramic body in which the internal electrode and the metal calcined body are embedded;
A base material preparation step for preparing the base material in which the connection member having a space in which no metal exists is embedded by firing the ceramic body in which the internal electrode and the metal calcined body are embedded;
A method for producing an electrode embedding member comprising: It is a manufacturing method of the electrode embedding member according to claim 1 or 2,
In the preparation step, the powder raw material is prepared by mixing at least two kinds of metal particles having different particle sizes. It is a manufacturing method of the electrode embedding member according to any one of claims 1 to 3,
The preparation step of preparing the metal formed body or the metal calcined body uses one or more kinds of the metal particles in the metal formed body,
One type of the metal particles have a particle size of 1 to 150 μm, and the volume ratio of all types of the metal particles is 80 to 100%.

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