JP7280059B2 - Method for manufacturing electrode-embedded member - Google Patents

Description

The present invention relates to a method of manufacturing an electrode-embedded member in which internal electrodes are embedded in a plate-like substrate made of ceramics.

2. Description of the Related Art Conventionally, there has been known an electrode-embedded member in which an internal electrode is embedded in a plate-like base material made of ceramics. In the electrode-embedded member, the connection member is arranged in advance at the location where the internal electrode and the terminal are to be connected so as not to damage the internal electrode when an insertion hole for connecting the terminal to the internal electrode is drilled in the substrate. Therefore, it is necessary to take measures such as preventing the internal electrodes from being damaged by the connection member. As such an electrode-embedded member in which an internal electrode is embedded, an electrode-embedded member provided with a connection member for connecting a terminal to an internal electrode embedded in a ceramic substrate has been proposed (see, for example, Patent Document 1).

JP 2010-34514 A

However, in the member manufactured by the manufacturing method disclosed in Patent Document 1, due to the influence of heat during the manufacturing process such as brazing, and due to repeated temperature changes during use, the coefficient of thermal expansion between the base material and the connecting member There is a risk that cracks will occur in the base material due to the difference in the thickness of the base material, and that the insulation performance of the base material will not be ensured.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing an electrode-embedded member that can suppress problems such as cracks in the base material.

[1] In order to achieve the above object, the method for manufacturing an electrode-embedded member of the present invention comprises:
a plate-shaped substrate having a front surface and a back surface and made of ceramics;
an internal electrode extending along the surface of the base material and embedded in the base material;
a connection member arranged to overlap the internal electrode;
a terminal hole drilled from the back surface of the base material to the end surface of the connection member inside the base material and having a smaller diameter than the connection member ;
a terminal arranged in the terminal hole and connected to the connection member;
A method for manufacturing an electrode-embedded member comprising
A preparatory step of preparing a metal compact to be the connection member by pressure-molding 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 substrate manufacturing step of firing the ceramic body in which the internal electrode and the metal molded body are embedded to manufacture the substrate in which the connection member having a space in which no metal exists is embedded;
characterized by having

[2] A method for manufacturing an electrode-embedded member according to another aspect of the present invention comprises:
a plate-shaped substrate having a front surface and a back surface and made of ceramics;
an internal electrode extending along the surface of the base material and embedded in the base material;
a connection member arranged to overlap the internal electrode;
a terminal hole drilled from the rear surface of the base material to an end surface of the base material inside the base material and having a diameter smaller than that of the connection member ;
a terminal arranged in the terminal hole and connected to the connection member;
A method for manufacturing an electrode-embedded member comprising
a preparation step of preparing a metal calcined body to be the connection member by calcining a metal compact obtained by pressure-molding 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 substrate manufacturing step of firing the ceramic body in which the internal electrode and the metal calcined body are embedded, thereby manufacturing the substrate in which the connection member having a metal-free space is embedded;
characterized by having

According to this manufacturing method, since the metal molded body or the metal calcined body can be manufactured in advance, the shape (particle diameter, pore size, The sintered structure of metal particles such as sintering ratio and average pore diameter), and by adding other components to the metal compact or metal calcined body, it is possible to adjust the adhesion between the connecting member and the base material and the thermal expansion coefficient. As a result, it is possible to suppress cracks in the base material when subjected to heat during manufacturing processes such as brazing and hot pressing, and when subjected to heat from thermal cycles during use of the electrode-embedded member. become easier.
Furthermore, the electrode-embedded member can be produced in which deterioration of electrical properties such as electrical conductivity is suppressed by appropriately sintering the metal particles of the metal compact.
Furthermore, the ceramics constituting the substrate penetrate into the spaces (open pores) of the connection member, and an electrode-embedded member can be manufactured in which the adhesion between the connection member and the substrate is further improved.

[3] Further, in the electrode-embedded 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 compact can be adjusted, and at the same time, spaces (open pores) are formed by the metal with a large grain size, and the metal with a small grain size is densified to some extent to contain two types of metal particles. makes it easier to adjust the adhesion to the base material and the coefficient of thermal expansion. In some cases, cracks in the substrate can be further suppressed.

[4] In the electrode-embedded member of the present invention, the preparing step uses one or more types of metal particles in the metal compact, and one type of metal particles has a particle size of 1 to 150 μm. It is preferable that the volume ratio of all kinds of metal particles is 80 to 100%.

By this process, even if the electrode-embedded member is used under more severe conditions such as a large temperature difference, it is possible to suppress cracks in the base material.

1 is an explanatory view schematically showing an electrode-embedded member of the present invention; FIG. It is explanatory drawing which shows the manufacturing method of the electrode embedded member of this invention. FIG. 4 is an explanatory diagram showing the state of metal particles before hot-press firing; FIG. 4 is an explanatory diagram showing the state of metal particles after hot-press firing;

Embodiments of the present invention will be described below with reference to the drawings. The drawing conceptually (schematically) shows the electrode-embedded member 1 .

As shown in FIG. 1, the electrode-embedded member 1 has a front surface 2a and a back surface 2b, and is made of aluminum oxide ( _Al2O3 ), aluminum nitride ( _AlN ), nitrogen carbide (SiC), silicon nitride ( _{Si3N4 )} . ), an internal electrode 3 extending in parallel with the surface 2a of the substrate 2 and embedded in the substrate 2, and a disk-shaped substrate along the surface 2a of the substrate 2 and a connecting member 4 arranged overlapping the internal electrode 3 extending to the inner electrode 3 .

A terminal hole 5 is formed in the base material 2 so as to extend from the rear surface 2b of the base material 2 to the end face of the connection member 4 inside the base material 2. As shown in FIG. The electrode-embedded member 1 also includes a rod-shaped terminal 7 that is arranged in the terminal hole 5 and connected to the connecting member 4 via a disk-shaped cushioning member 6 . The buffer member 6 and the terminal 7 are joined to the connection member 4 by brazing or the like.

The internal electrodes 3 and connecting members 4 are made of tungsten, molybdenum, or an alloy containing these as main components. The terminal 5 has a cylindrical shape and is made of a low thermal expansion metal alloy such as Kovar, nickel, titanium, copper, or an alloy containing these as main components. It is connected.

The diameter of the terminal hole 5 is 5 mm. 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 an inner surface 11 of the substrate 2 defining the terminal hole 5 . The width of the gap 12 is 0.1 mm.

Next, a method for manufacturing the electrode-embedded member 1 will be described. The method of manufacturing the electrode-embedded member 1 includes a preparation step of preparing the metal molded body 4a or the metal calcined body, a ceramic body manufacturing step of manufacturing the ceramic body 2c, and a base material manufacturing process of manufacturing the base material 2. At least include. Before the step of preparing the metal molded body 4a or the metal calcined body, a step of preparing the powder raw material 15 by mixing at least two types of metal particles 14a and 14b with different particle sizes may be performed.

[Step of preparing powder raw material 15]
As shown in FIGS. 2A and 3, the step of preparing the powder raw material 15 obtains the powder raw material 15 by mixing at least two types of metal particles 14a and 14b with different particle sizes. In the embodiment, the powder raw material 15 is a mixture of two types of metal particles 14a and 14b, but is not limited to this. It is good also as a form which carries out.

[Preparation step for preparing metal compact 4a or 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 pressure-molding the powder raw material 15 containing the plurality of metal particles 14 shown in FIG.

Specifically, a powder raw material 15 in which a binder 16 is added to a plurality of metal particles 14 shown in FIG. A disk-shaped metal compact 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. For the purpose of removing the binder 16, a degreasing step may be performed in which the molded body 4a is degreased at a temperature of 200° C. to 600° C. in an air atmosphere or a nitrogen atmosphere.

In the embodiment, the metal compact 4a is only pressure-molded, but the metal compact 4a is calcined in a nitrogen, argon, or vacuum atmosphere furnace under a temperature condition of, for example, 1000° C. or higher and 1800° C. or lower. may be performed and the metal molded body 4a may be used as a calcined body. This corresponds to a preparatory step of preparing a metal calcined body that will be a connecting member by calcining a metal molded body obtained by pressure-molding a powder raw material containing a plurality of metal particles.
In this preparatory step, the outer diameter and thickness of the metal calcined body may be adjusted by grinding or polishing.

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

Specifically, an insulating layer is formed. A powder mixture consisting 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. Thus, a first layer (insulating layer) having a diameter of 340 mm and a thickness of 5 mm was formed.

Next, the internal electrodes 3 are installed. A molybdenum foil (thickness: 0.1 mm) having a diameter of 290 mm and serving as the internal electrode 3 was placed on the first layer. On the internal electrode 3, a disc-shaped metal compact 4a or metal calcined body made of tungsten and having a diameter of 10 mm and a thickness of 0.5 mm is placed. Twenty metal compacts 4 a or metal calcined bodies were provided on one substrate 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 where the metal molded body 4a or the metal calcined body is to be overlapped.

A second layer is then molded. 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 is uniaxially pressed 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, opening: 50 mesh) formed in a predetermined pattern is arranged for the purpose of heating the electrode-embedded member 1 itself as a wafer holding device, and a predetermined heater terminal is connected. A connecting member for a heater terminal (tungsten pellet, diameter 10 mm, thickness 0.5 mm) is placed on the connecting position.

Next, a compact before firing is formed. A ceramic powder is filled on the heater electrode and uniaxially pressed to form a third layer.

[Substrate production step for producing substrate 2]
In the process of producing the base material 2, the ceramic body 2c in which the internal electrode 3 and the metal molded body 4a or the metal calcined body is embedded is fired to form a space 17 (see FIG. 4) in which no metal is present. A 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 firing.
Specifically, a firing step is performed. In the sintering step, the laminate laminated up to the third layer was subjected to hot press sintering at a pressure of 10 MPa, a sintering temperature of 1800° C., and a sintering time of 2 hours to obtain a ceramic sintered body with 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 the wafer mounting surface (surface 2a) was formed.

Next, terminal 7 is connected. Holes (diameter 5 mm) are drilled from the rear surface 2b of the fired ceramic base so as to reach the positions of the connection members 4, and cylindrical terminal holes 5 extending from the rear surface 2b to the connection members 4 are formed. . A kovar cushioning member 6 having a diameter of 4.8 mm and a thickness of 2 mm is placed on the connection member 4 defining the terminal hole 5 via an Au—Ni brazing material. Next, a columnar nickel feed terminal 7 having a diameter of 4.8 mm and a length of 200 mm is placed on the buffer member 6 via a brazing material obtained by adding Ti as an active metal to Au--Ni. After that, brazing was performed by heating at 1050° C. in a vacuum furnace to complete the electrode-embedded member 1 .

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

Next, the effect of the manufacturing method of the electrode-embedded 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 configuration of the porous connecting member 4 obtained by firing the metal molded body 4a or the metal calcined body (sintered structure of metal particles such as particle size, porosity, average pore diameter) and other components are included in the metal molded body 4a or the metal calcined body to improve the adhesion between the connecting member 4 and the base material 2. and the thermal expansion coefficient can be adjusted. It becomes easier to suppress cracks in the base material 2 .

Furthermore, the metal particles 14 of the metal molded body 4a are sintered appropriately to produce the electrode-embedded member 1 in which deterioration of electrical properties such as conductivity is suppressed.

Furthermore, the ceramics forming the base material 2 enter the spaces 17 (open pores) of the connection member 4, so that the electrode-embedded member 1 with improved adhesion between the connection member 4 and the base material 2 can be manufactured.

By including the step of preparing the powder raw material 15 by mixing at least two types of metal particles 14a and 14b with different particle sizes, the two types of metal particles 14a and 14b are included to improve adhesion with the substrate 2 and thermal expansion. It becomes easier to adjust the coefficient, and as a result, cracks in the base material 2 are more suppressed when subjected to heat during manufacturing processes such as brazing and hot pressing, and when subjected to heat from heat cycles during use. can do

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

Normally, when the metal particles 14 are sintered, the necking portion grows and densification progresses. 17 is formed.

For this reason, the connection member 4 can be configured to have a porous structure made of the metal particles 14 . By making it porous, the difference in expansion rate and contraction rate induced by the difference in the physical properties of the ceramics constituting the connection member 4 and the base material 2 can be suppressed. It is possible to suppress defects such as cracks in the base material 2 and cracks in the connection member 2.

Next, the electrode-embedded member 1 was evaluated using the connection member 4 produced by changing the particle size and mixing ratio of the metal particles 14 .

As an evaluation method, after heating the fabricated electrode-embedded member 1 to 600° C. and then cooling it to room temperature, a thermal cycle was repeated 10 times, and then the occurrence of cracks was visually confirmed. After that, the terminal 7 was subjected to a tensile test, and the presence or absence of crack generation was confirmed by scanning electron microscope observation (SEM observation) of the cross section of the electrode-embedded member 1 . The number of locations where cracks occurred on the surface 2a side of the base material 2 directly above the terminal 7 was counted, and 0 out of 20 connecting members 4 were evaluated as suitable, and those with 1 or more cracks were evaluated. It was evaluated as unsuitable.

In Examples 1 to 5, the first metal particles 14a are tungsten coarse particles, the second metal particles 14b are tungsten powder, and the particle size and mixing ratio (volume mixing ratio) of each metal are changed. The molded body 4a is produced and used as the electrode-embedded member 1 by the manufacturing method described above.

In Example 6, after the metal compact 4a was produced using only the first metal particles 14a, which are tungsten coarse particles, the metal compact 4a was calcined under the conditions of 1500° C. in a nitrogen atmosphere. The electrode-embedded member 1 was manufactured in the same manner as described above, except that a metal calcined body processed into a disk shape with a thickness of 0.5 mm was used in place of the metal molded body 4a of Examples 1 to 5. It is what I did.

In Comparative Example 1, the electrode-embedded member 1 was produced by the above manufacturing method, except that a disk-shaped tungsten pellet having a diameter of 10 mm and a thickness of 0.5 mm was used in place of the metal compact 4a.

In addition, for the raw material powders (metal particles 14a and 14b), the particle size is measured using a general particle size distribution analyzer (laser analysis method, gravity sedimentation method), scanning electron microscope observation (SEM observation), particle size gauge, etc. to confirm. Table 1 shows the range of particle diameters of the first metal particles 14a and the second metal particles 14b. and the median value of this range was taken as the representative particle size. Moreover, the electrode-embedded member 1 is confirmed by SEM observation of its cross section.

The table below shows the above evaluation results.

As a result, it was found that in Examples 1 to 4, the number of crack generation locations was 0, and the reliability was high. In Example 5, the number of cracks was one, and it was found that the reliability was lower than in Examples 1-4. This is because the tungsten particles have a particle diameter of 0.6 to 1 μm, and the sintering of the tungsten particles proceeds, and after firing, it looks like a bulk body, and the tungsten is too densely sintered. 4, the cracks are presumed to have occurred due to the stress due to the difference in thermal expansion coefficient.

In Example 6, no cracks were generated, indicating high reliability. This is because the representative particle diameter of the first metal particles was slightly larger than that in Example 5, and that a metal-free space was previously created inside the connecting member 4 by embedding the metal calcined body. It is presumed that this is because the relaxation effect of the stress induced around the connection member 4 has been solidified.

Comparative Example 1 is an example applied to a conventional electrode-embedded member, and the number of cracks generated was 4. It was found that the reliability was extremely low and not practical. This is because the grain growth of the tungsten structure constituting the pellet progressed too much due to the sintering temperature of 1800 degrees, the strength of the pellet decreased, cracks occurred in the pellet itself, and between the base material 2 and the connecting member 4 , it is presumed that the cracks were caused by the stress due to the difference in thermal expansion coefficient.

Thus, in the preparation step of preparing the metal compact 4a or the metal calcined body, one or more types of metal particles 14a are used in the metal compact 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 severe conditions such as a large temperature difference. It is possible to suppress cracks in the base material 2 .

In the so-called green sheet laminated product, the electrodes are generally formed by printing, and the grain size of tungsten is adjusted to 1 μm or less. Further, the thickness of the outer edge of the electrode is reduced by printing and becomes sharp. As a result, the structure after sintering loses its original grain size and integrates (densifies), and takes a form in which stress is likely to occur at the outer edge of the electrode.

On the other hand, granules with a relatively large particle size (granules with a particle size larger than the particle size of the tungsten paste of the green sheet laminate) have a large particle size and require a higher sintering temperature, which leads to integration ( As a result, the structure becomes porous (a state in which particles are necked and partially sintered). Further, by subjecting the metal molded body 4a or the metal calcined body to be the connection member 4 to machining, the thickness and outer shape of the metal molded body 4a or the metal calcined body to be the connection member 4 can be adjusted, and after firing stress concentration in the connection member 4 can be suppressed.

In the embodiment, the connecting member 4 and the buffering member 6 are bulk bodies made of tungsten, molybdenum, or an alloy containing these as main components, but are not limited to this, and have a smaller average linear expansion coefficient than the terminal 7. Other common materials may be used as long as the material of .

Although the width of the gap 12 is set to 0.1 mm in the embodiment, the width of the gap 12 is not limited to this. Furthermore, it does not matter if the terminal 7 is in contact with the terminal hole 5 and the gap is zero. Also, 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-embedded member 2... Base material 2c... Ceramic body 3... Internal electrode 4... Connection member 4a... Metal compact 5... Terminal hole 7... Terminal 14... Metal particle 14a... First metal particle (coarse particle)
14b... second metal particles (powder)
17. Space

Claims (4)

a plate-shaped substrate having a front surface and a back surface and made of ceramics;
an internal electrode extending along the surface of the base material and embedded in the base material;
a connection member arranged to overlap the internal electrode;
a terminal hole drilled from the back surface of the base material to the end surface of the connection member inside the base material and having a smaller diameter than the connection member ;
a terminal arranged in the terminal hole and connected to the connection member;
A method for manufacturing an electrode-embedded member comprising
A preparatory step of preparing a metal compact to be the connection member by pressure-molding 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 substrate manufacturing step of firing the ceramic body in which the internal electrode and the metal molded body are embedded to manufacture the substrate in which the connection member having a space in which no metal exists is embedded;
A method for manufacturing an electrode-embedded member, comprising: a plate-shaped substrate having a front surface and a back surface and made of ceramics;
an internal electrode extending along the surface of the base material and embedded in the base material;
a connection member arranged to overlap the internal electrode;
a terminal hole drilled from the rear surface of the base material to an end surface of the base material inside the base material and having a diameter smaller than that of the connection member ;
a terminal arranged in the terminal hole and connected to the connection member;
A method for manufacturing an electrode-embedded member comprising
a preparation step of preparing a metal calcined body to be the connection member by calcining a metal compact obtained by pressure-molding 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 substrate manufacturing step of firing the ceramic body in which the internal electrode and the metal calcined body are embedded, thereby manufacturing the substrate in which the connection member having a metal-free space is embedded;
A method for manufacturing an electrode-embedded member, comprising: A method for manufacturing an electrode-embedded member according to claim 1 or 2,
A method of manufacturing an electrode-embedded member, wherein in the preparing step, the powder raw material is prepared by mixing at least two kinds of metal particles having different particle sizes. A method for manufacturing an electrode-embedded member according to any one of claims 1 to 3, comprising:
The preparing step uses one or more kinds of the metal particles in the metal compact,
A method for manufacturing an electrode-embedded member, wherein the particle size of one kind of the metal particles is 1 to 150 μm, and the volume ratio of all the kinds of the metal particles is 80 to 100%.

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