JPS6057212B2 - Single sintered ceramic body and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single sintered ceramic body for manufacturing a multilayer ceramic capacitor and a method for manufacturing the same.

A multilayer porcelain capacitor using this single sintered ceramic body and a method for manufacturing the same are disclosed in Japanese Patent Application No. 1983-1985 filed by the present applicant.
This is the subject of No. 36773. Multilayer electrical components made of ceramic materials, such as multilayer ceramic capacitors, are widely used in electrical circuits.

These capacitors generally consist of a plurality of alternating dielectric and conductive thin layers, the latter being used as internal electrodes. These capacitors are formed as a rigid unitary body with extremely high capacitance per unit volume. These common manufacturing methods involve casting thin sheets of the desired pulverized dielectric ceramic composition using a resin as a temporary binder. The metal-containing electrode paste is then applied to predetermined areas on the sheets, often by silk-screening, to create multiple electrode areas on each sheet. After the thin plates coated in this way are properly oriented and overlapped, they are pressed and fixed. The bonded laminar green ceramic blocks are suitably cut to obtain individual units. These units are heated and fired to burn out the binder in the thin plates and electrode layers and to sinter the ceramic material, thereby forming a compact ceramic-metal structure. When the thin plates are properly coated, oriented, laminated, and cut in this way, the multiple electrode thin layers in each single body are properly arranged and each thin layer is exposed only on one end surface of the single body. However, immediately adjacent electrode thin layers are exposed on opposite end surfaces of the unitary body. In this way, two sets of insulated internal electrodes are formed. Next, attach the terminal electrode to the end surface where the electrode is exposed! Install and electrically connect the internal electrodes alternately. In the method described above, since the ceramic and the internal electrode are fired together, the metal and ceramic of the internal electrode must be able to withstand high temperatures, such as 00°C.

Also, since the optimum dielectric properties of ceramics are obtained when firing is performed in a tetraoxidizing atmosphere, the metal must be resistant to oxidation at these temperatures. Therefore, since noble metals with high melting points, such as palladium, platinum, and their alloys with gold are used for the internal electrodes, the manufacturing cost of this type of multilayer capacitor is high. U.S. Pat. No. 2,919,483 discloses a method of manufacturing a laminated ceramic capacitor that does not require the presence of internal metal electrodes when firing the ceramic to harden it.

Further, US Pat. No. 3,679,950 discloses a method of manufacturing a laminated ceramic capacitor and a laminated ceramic circuit board using relatively inexpensive metals for internal electrodes. The method described in U.S. Pat. The porous stacks are the same size, the same shape, and are oriented the same as the prior art noble metal electrodes (ie, the immediately adjacent porous stacks have open ends on opposite sides of the chip). Metal is then introduced into the porous ceramic laminate and end electrodes are attached to the opposing surfaces to form a laminate capacitor. According to this method, metals such as lead, tin, and silver can be used for the internal electrodes. A similar method is used to manufacture laminated ceramic circuit boards with internal electrodes. US Pat. No. 3,679,995 A particularly convenient method for introducing metal to form internal electrodes within the porous thin layer of a monolithic ceramic produced by the method described in the specification is to introduce the metal under pressure. .

However, a problem often arises where the metal from the molten metal bath cools and bonds two or more ceramic units together. It is therefore desirable to keep this ceramic body separate during the introduction of the metal, but to date there is no fully satisfactory method of accomplishing this. Furthermore, a laminated ceramic element (
In the manufacture of capacitors, for example, the attachment of end face electrodes requires additional firing and the electrode compositions used are expensive. In view of the above, it is a primary object of the present invention to provide a single sintered ceramic body in which metal can be easily introduced into the ceramic body to form internal electrodes at a lower cost and more effectively.

The purpose is to create a large number of superimposed dense ceramic dielectric thin layers, a thin spatial region between these thin layers, a dielectric ceramic outer wall covering the entire outer periphery of these spatial regions, and a large number of dense a first longitudinal hole extending through a thin layer of dense ceramic dielectric and passing through every other spatial region but not communicating with every other remaining spatial region; penetrating the thin layer and said residual 1
This is achieved by a single sintered ceramic body consisting of a second longitudinal hole passing through every third spatial region but not communicating with said first every other spatial region.

The single sintered ceramic body is formed by forming a plurality of thin plates of pulverized sinterable dielectric ceramic material, applying a thermally incinerating material to the thin plates in a smaller area;
These coated thin plates are stacked so that the heat-combustible material layer is sandwiched between adjacent ceramic thin plates, and the entire outer periphery of these heat-combustible material layers is sealed with a dielectric ceramic material to form a raw ceramic laminate. A pair of spaced apart holes vertically penetrating the ceramic laminate are formed such that the first hole penetrates every other layer of the thermally combustible material, but the remaining thermally combustible material layer penetrates every other layer. spaced apart from the layer and a second hole is drilled through said remaining every other layer of thermally incinerable material but spaced apart from said first every other layer of thermally infernible material; It is manufactured by firing in an oxidizing atmosphere at a temperature of 0.degree. The cross-sectional area of the linear or cylindrical metal conductor wire, that is, the lead wire, which is inserted in order to refine the multilayer ceramic capacitor, is made slightly smaller than the hole so that it can be pulled out from the hole with a certain amount of force, and the lead wire Molten metal can be injected through the gap between the hole and the hole.

As can be seen, the metal of the metal bath not only fills the spatial regions between the dielectric thin layers to form internal electrodes as described in U.S. Pat. It also fills the gaps.

As a result, the conductive wire inserted into the hole functions as a lead wire of a single ceramic body filled with metal. This is because each conducting wire is electrically connected to only one of the two sets of internal metal electrodes. By using the above-mentioned ceramic unit according to the present invention, it is possible to communicate the electrode areas between the dielectric thin layers through the holes, so that the unitary body does not have the open area at the end face of the unitary unit as in the conventional case. (In FIG. 6, the electrode region 33 terminates a little short of the left-hand end of the single laminate).

That is, molten metal is introduced into the electrode area only through the holes. However, if desired, it is also possible to provide a hole for the lead wire in the ceramic unit so that the electrode area reaches the end face of the unit (in Figure 7, the electrode area is located at the left hand end of the stacked unit). ).
In this specification, the term ``one electrode area'' is used in a broad sense, and refers not only to an area in which an electrode is formed inside a ceramic structure, but also to a spatial area in which an electrode can be formed in the future. Refers to an area of any shape and size known in the capacitor art as an electrode-formed or electrode-formable area.

Objects and advantages of the invention will become apparent from the following details, taken in conjunction with the accompanying drawings.

The accompanying drawings are enlarged views of the embodiments with varying scale.

FIG. 1 shows one embodiment of a multilayer ceramic capacitor using the single sintered ceramic body of the present invention.

It consists of a sintered ceramic structure with vertically spaced horizontal thin metal layers (ie internal electrodes) 21 and 22. The electrodes 21 and 22 are arranged alternately, and in FIG. 1, the electrode 21 extends longer than the electrode 22 in the direction of the left end surface, whereas the electrode 22 extends longer than the electrode 21 in the direction of the right end surface. ing. Thus, as shown in FIG. 4, the lead wires 25 pass through the holes aligned vertically in close proximity to the end surface 23 and are electrically connected to the holes of one electrode 21.Similarly, the lead wires 26 The other electrode 22 passes through the alignment hole in a vertical direction close to and parallel to the end surface 24.
Only make electrical connections. The conductive wires 25 and 26, which function as the leads of the capacitor, are held in place by bends 28 at the position where the leads emerge from the upper side of the ceramic laminate, before providing internal electrodes within the capacitor as described below. , the lead wire has a similar bend at the end of the lead wire at a location where it exits the lower surface of the ceramic laminate. or,
The free lower end of the conductor may be provided with a knot 29 as shown in FIG. FIG. 5 is essentially similar to FIG. 4, but shows a partial cross-section of a smaller capacitor. If desired, a knot may be used in place of the bend to hold the lead wire at the top surface of the ceramic laminate.
The manufacturing of the capacitor shown in FIG.
A single sintered structure, i.e., a ceramic monomer, having multiple superimposed thin layers of ceramic dielectric material with intervening electrode regions was prepared using substantially the same method as described in No. 99(99). Form into one piece or small blocks.

In that patent, the electrode region is a porous ceramic dielectric thin layer, each thin layer having a network of interconnected cavities. Also, in this patent, one electrode region extends to one end surface, and the other electrode region extends to the other end surface. In the present invention, the method of the above-mentioned US patent is slightly modified since there is no need for the electrode area to reach the end face and be opened. This modification involves coating thin plates of dielectric ceramic material with a thin layer of temporary conductor made of thermally incinerating material to form the electrode areas, and stacking these coated plates so that every other electrode area is connected to one end surface. The remaining every other electrode area is arranged to extend longer than the other end face in the direction of , but the entire outer periphery including both end faces is sealed with a dielectric ceramic material so that these electrode areas are not exposed to the outside. It's something I'm used to doing. Therefore,
In the present invention, firing the ceramic structure results in a completely sealed sintered ceramic unit containing two sets of thin electrode regions within which a conductive material, e.g. a metal, is later introduced. to form a metal electrode. In order to introduce metal into the electrode region within the sintered ceramic unit described above, a pair of holes are provided in the ceramic unit as follows. In other words, one hole covers one electrode area.
The residual penetrating every third time. a pair of holes spaced apart from every other electrode area and such that the other hole passes through said remaining every other electrode area but spaced apart from said first every other electrode area; is bored into a single ceramic body to communicate between its top and bottom surfaces. This is shown in cross section in FIG. A ceramic structure (i.e. a single ceramic body) in which vertical holes 31 communicate with alternating electrode areas 33
Another remaining electrode area 35 is communicated proximately to the opposite end (not shown) of the chip by another vertical hole (not shown).

The holes in the ceramic body communicating the electrode areas may be formed by drilling or stamping. Although the holes may be created in the ceramic unit after the ceramic has been fired to sinter the ceramic, it is preferable to provide the holes in the green, unfired ceramic unit. Before introducing the metal into the electrode area of the fired ceramic unit, the lead wire (
A conductive wire or rod) is inserted into or passed through the hole and suitably fixed in position as previously described. The diameter of the wire or rod used is somewhat smaller than the hole into which it is inserted to provide sufficient clearance around the wire for the molten metal to penetrate into the electrode area of the ceramic unit and form an internal electrode of the specified size. Any suitable method may be used to introduce the metal into the thin electrode region of the sintered ceramic monolith to form the inner electrode, e.g., attaching the leads as previously described. The sintered ceramic unit is heated to a temperature of about 350°C to 500'C in a suitable container.
It may be immersed in a molten lead bath maintained at Preferably, the container is located in a variable pressure enclosure. The reason for this is that in order to introduce molten metal from around the conductor into the electrode area of a single ceramic body, the pressure inside the sealed body must first be increased.
For example, this is facilitated by reducing the pressure to about 76.5 Tr$THg and then increasing the pressure after immersing the unit in molten metal. The metal is thus pressed into the ceramic body. A pressure of about 14k9/Cd is known to be suitable for this purpose. After metal introduction, the ceramic unit is removed from the metal bath, cooled, and the pressure restored. Therefore, a capacitor with lead wires attached as shown in FIG. 1 can be obtained without requiring end face electrodes and without requiring a soldering process for attaching such lead wires. Many metals other than lead can also be used to form internal electrodes within the ceramic unitary body according to the present invention. For example, tin, aluminum, copper, and alloys thereof may be used as required. Obviously, the metal or alloy used must have a low melting point so that its incorporation into the ceramic body can be carried out at moderate temperatures, and must not substantially evaporate at the temperatures of use and have no adverse effect on the ceramic dielectric material. It is preferable not to have one. The minimum temperature at which the molten metal is injected into the ceramic body clearly depends on the dimensions of the hole and electrode area, the viscosity of the molten metal, and the surface energy of the molten metal relative to the sintered ceramic material. Generally, it is necessary that the melting point of the metal introduced into the electrode region of the sintered ceramic solid body be lower than the sintering temperature of the single body. The metal other than the internal electrode and the lead wire in the hole filled is solidified molten metal and has the characteristics of cast metal. FIG. 11 schematically shows, as a reference example, one of a number of methods for producing metal internal electrodes.

In this figure, reference numeral 39 indicates a suitable container or closure. A container 40 made of a suitable material and containing the molten metal bath used is placed therein. The metal bath is heated by a suitable method not shown to maintain the metal at a suitable temperature. Similarly, a carrier is provided inside the closed body. Although the structure of the carrier may vary, it is preferred that the carrier include a support bar 42 that reciprocates in a vertical direction. A spring clip 43 is attached to the lower end of this bar 42, thereby removably holding one or both of the lead wires 44 attached to the previously described sintered ceramic structure, ie, the ceramic unitary body 45. . Therefore, after suspending the ceramic unit 45 inside the enclosure 39, the pressure inside the enclosure is reduced by a suitably connected vacuum pump (not shown), and then the unit is suspended by the rod 42. Lower into the molten metal bath.

The pressure inside the enclosure is then increased by suitable means (not shown) to force the molten metal around the lead 44 into the electrode area within the ceramic body. Compressed gas from any suitable source may be used as the pressure medium. Then,
The rod 42 is raised to remove the ceramic unit 45 from the metal bath, cool it sufficiently to solidify the metal therein, and then remove the pressure. The manufactured capacitor is then removed and replaced with another ceramic unit and the metal pressing process is repeated. Other methods and devices may be used to introduce molten metal into the sintered ceramic body. For example, under certain conditions, evacuation of the enclosure may occur after immersion of the ceramic unit into the molten metal bath. Similarly, multiple carriers may be provided and two or more ceramic units may be immersed simultaneously into the metal bath. If desired, the metal introduction equipment may be automated to continuously produce finished capacitors. FIG. 8 shows an example of an arrangement for providing leads in a single sintered ceramic body according to the invention prior to the introduction of metal into the electrode area between the thin dielectric layers. FIG. 8 is a cross-sectional view perpendicular to FIG. 6, showing that the holes 47 and 48 in the ceramic body passing through the two sets of electrode regions 49 and 50, respectively, between the thin dielectric layer 51 are larger. , make it inclined instead of vertical. Therefore, after the conductors or rods (not shown) for the leads have been inserted into the holes 47 and 48 and the molten metal has been introduced into the regions 49 and 50 through the holes around the leads, the conductors or The contact area between the bar and the internal electrode formed of metal in the electrode area is somewhat increased. FIGS. 9 and 10 also show reference examples.

Here, before firing the ceramic body and filling the electrode regions therein with metal, a cavity is provided in the side of the green ceramic body. Each of such cavities within the sintered ceramic unitary body 52 (one of the cavities 54 is
It communicates with a pair of electrode regions 55 and 56 located between a dielectric ceramic thin layer 53 (as shown in FIG. 0). Therefore, the cavity 54
are in communication with and coupled to electrode regions 55, while similar cavities (not shown) at opposite ends of the ceramic unit communicate with alternating electrode regions 56. Electrode area 5 of molten metal after firing
5 and 56, the flattened end 57 of a bar or conductor 58 is inserted into the generally rectangular cavity 54, and a similar flattened bar or conductor (not shown) is inserted into the opposite end of the ceramic unit. into the corresponding cavity (not shown) of the. The end of the conducting wire or rod is sufficiently fitted within the cavity so that it is held by friction and does not fall out with some force. At the same time, however, this fit prevents molten metal from penetrating into the cavity around the flattened end and into the respective electrode area communicating with it when the ceramic unit is immersed in a molten metal bath. After the metal-loaded unit is removed from the metal bath and cooled, the ends of the flat conductor or bar are held firmly within the cavity, and the lead wire and internal metal electrode Figures 2 and 3 show another embodiment using the sintered ceramic body according to the invention.

In this embodiment, the laminated ceramic capacitor 59 includes two sets of internal metal electrodes 60 and 61, which are present on every other pair. Each of the electrodes 60 is connected to an electrode 61 toward the front end of the capacitor.
, and each of the electrodes 61 extends beyond electrode 60 toward the rear end of the capacitor, but none of these electrodes are exposed to the exterior of the capacitor. Near the front end of capacitor 59 (FIG. 2), lead wire 62 is inserted through the spaced-apart hole, through the sintered ceramic thin layer and electrode 60, and is placed along the bottom surface of the capacitor. The capacitor thus has a free end of the lead wire projecting from its top surface. As shown in the figure, the hole for the lead wire 62 is arranged so that the lead wire is connected to the electrode 60 and not connected to the electrode 61. A lead wire 64, similar to lead wire 62, is provided near the rear end of the capacitor and passes through the same hole through the center line within ceramic thin layer 63. This hole is
The lead wire 64 is arranged so as to be connected to the internal electrode 61 but not to the electrode 60. Leads 62 and 64 are inserted into the ceramic body before the metal is injected into the body, and bends 66 or knots are provided at the free ends of the leads as in FIG. Prevent falling off.
In manufacturing the capacitors shown in FIGS. 2 and 3, a method very similar to that of the aforementioned US patent is used.

The green ceramic unit is created by alternating thin layers of temporarily bonded dielectric ceramic material and thereby thin layers of small area temporary conductor. Holes are then drilled or otherwise placed through these thin layers and the ceramic body is then fired to sinter the thin layer of ceramic dielectric material and form the thin layer of temporary conductor. is incinerated to form a thin electrode space between the thin dielectric layers.

The temporary conductor thin layer is sealed at its outer edge by a dielectric ceramic material so that it is not exposed to the outside, and in addition, every other temporary conductor layer and every other remaining temporary conductor layer are opposite to each other. It extends longer in the direction of the end face so that upon firing, spaces for two sets of electrodes are formed inside the ceramic laminate. In the embodiment of FIGS. 2 and 3, the lead wire holes are provided in aligned pairs near opposite ends of the laminate; The holes pass through and communicate with one set of electrode regions, and the other pair pass through and communicate with the second set of electrode regions. Obviously, neither hole penetrates through the areas of both adjacent sets of electrodes. Because,
This is because this means a short circuit in the capacitor. After firing the ceramic unit, a conductive wire slightly smaller in diameter than the hole is passed through each hole, with the free end of each conductive cotton protruding from the top surface of the fired laminate, and one of each conductive wire is portions are arranged along the bottom surface of the laminate to extend from one hole of each pair to the other hole of that pair. One or both ends of one or both conductive wires are used to support and carry a ceramic monolith which is then implanted with metal as previously described to form internal electrodes within the electrode region. Each conductive wire is electrically connected to one set of internal electrodes so that the conductive wires function as leads for the completed capacitor. The capacitor structure shown in FIGS. 2 and 3 is extremely useful in attaching a capacitor to a circuit board or substrate by soldering.

An example of such use is shown in FIGS. 12 and 13, in which a spaced metallic solder 7 is placed on one side of a substrate 69 of a suitable insulating material.
0 and 71 are provided, and the solders are connected to conductors 72 and 73, respectively. A capacitor 74 constructed substantially similar to the capacitors of FIGS. 2 and 3 is connected to the solder 7 by the end surfaces of respective leads 75 and 76 projecting from the bottom of the capacitor.
Connect to 0 and 71. In this way a firm and stable contact surface is obtained. FIG. 14 shows one of the various uses of the leads from a capacitor using the sintered ceramic body of the present invention, such as the capacitor shown in FIG. As shown, leads 83 and 84 of capacitor 81, which respectively connect to alternating internal electrodes (not shown) within the capacitor, pass through respective holes 85 and 86 in circuit board 82 of a suitable insulating material. and pass through corresponding holes in conductors 87 and 88 provided on the underside of the circuit board. The leads hold capacitor 81 in place and good electrical connection between the leads and conductors 87 and 88 is achieved by soldering the leads to the conductors as shown at 89. Single firing according to this invention. Capacitors using a square ceramic body are substantially hermetically sealed by being encapsulated within a sintered ceramic material and by filling the gap around the conductor in the lead hole with metal; It can also be sealed further.

For example, in FIG. 15, a suitable sealing composition 91
is applied around the protrusion of the lead wire 92 of the capacitor 93. Similarly, in FIG. 16, the entire capacitor 95 can be encapsulated by a coating 96 of a suitable material and sealed around leads 97 and 98. Known polyethylene or epoxy resins designed for encapsulating electrical components may be used. These suitable sealing and encapsulating materials are commercially available. Capacitors of the types shown in FIGS. 1, 2, 5, and 18, as well as capacitors manufactured with internal metal electrodes inside ceramic laminates of the types shown in FIGS. 6 and 8, are similarly manufactured. Can be sealed. As previously noted, capacitors using the sintered ceramic body of the present invention do not require end face electrodes.

This is because the metal forming the internal electrodes is introduced through holes for conducting wires or rod lead wires provided in the sintered ceramic unitary body. Therefore, the lead wire itself is electrically connected to the two sets of internal electrodes. Therefore, the electrode area between the ceramic thin layers does not need to be exposed to the outer surface of the ceramic unit. However, if necessary,
After these are exposed and the end electrodes are attached as described below, the openings to such areas may be covered and closed from the outer surface of the unitary body. FIG. 7 is a reference example, and shows a ceramic structure 10 similar to the structure shown in FIG.
3, in which a dielectric sintered ceramic thin layer 1
04 and electrode space regions 105 and 106 smaller in area and into which metal is introduced alternately.

Region 105 extends to an end surface 107 of the structure.
Region 106 similarly extends to an opposite end surface (not shown) of structure 103. Both sets of electrode areas are surrounded on three sides by the structure. An end face member 109 is provided to cover the entire surface 107. The end member 109 is made of a ceramic material, for example, a low melting point. It is convenient to form it from glass,
It is also hermetically insulating. The reason is that spatial area 1
The metal forming the electrodes in 05 and 106 is introduced into structure 103 through a hole with a lead wire (not shown) passing through the structure perpendicular to this region. It is from. One such hole 111 near the end face 107 of the structure 103 allows the electrode space region 105 to communicate with the outside;
Other substantially identical holes (not shown) are provided near opposite end faces of structure 103 to provide communication between electrode space region 106 and the outside world. Another embodiment using the sintered ceramic body of the present invention is shown in FIGS. 17 to 19.

In the structure shown in FIGS. 18 and 19, reference numeral 1
19 indicates a multilayer capacitor with vertical lead wires or lead rods 121 and 122 passing through a vertical hole 120, and the lead wires are bent at the upper and lower sides of the capacitor as indicated by reference numeral 123 and easily fall off. to prevent From the developed view of FIG. 17, the method of manufacturing this structure will be readily apparent.

Reference numeral 125 designates a thin plate made of a finely ground dielectric ceramic material, such as barium titanate, temporarily bonded with a hot plate bonding material, such as a resin. Lower 4 thin plates 12
5, a temporary electrode thin film 126 made of a completely thermally incinerated material (or such a material mixed with inorganic particles) is attached. Lamina 126 is also preferably temporarily bonded with a hot plate bonding material. The temporary conductor, temporary electrode thin layer 126 and dielectric ceramic thin plate 125 are assembled as described in the aforementioned US patent or the present invention.

However, it should be noted that in this example, each thin layer of temporary conductor does not extend to the edge of the ceramic sheet, and all thin layers of temporary conductor are the same distance from each end. It is. This corresponds to each temporary conductor thin film 126.
This is the result of having a relatively large opening 127 spatial area within. The openings 127 in adjacent thin films 126 are offset from each other, and the openings in every other thin layer 126 are aligned vertically, and are pressed together to form a plurality of thin plates 125 as shown in FIG. When the membrane 126 is assembled, the material of the adjacent membrane 125 is forced into the opening 127 to form an insulating region therein. When this solid body is heated and fired at a sintering temperature, the thermally incinerable material of the temporary conductor thin film 126 is incinerated and the ceramic material within the thin plate 125 is sintered to form a single ceramic structure. It consists of a plurality of dielectric ceramic laminates 129 held together by ceramic material projecting around the edges and into the opening 127, as shown in FIGS. 18 and 19. After firing, such protruding ceramic material forms respective insulating regions, ie, insulating islands, in the electrode space regions interposed between the thin dielectric layers 129. The dimensions of opening 127 in membrane 126 may vary.

In general, it should not be larger than necessary to achieve its function, which is achieved by integrating the upper and lower ceramic sheets of the opening during sintering to provide an insulating area within the electrode area. This is to pass the lead wire through the area. If this insulating region is larger than necessary, the capacitance will decrease. Electrodes 130 and 131 are preferably metal and lead wires 121 and 12 are heated to incinerate the thermally incinerating material of temporary conductor film 126 into the electrode area.
Molten metal is introduced through holes 120 around the 2. The introduction of molten metal into such an electrode region can be carried out, for example, in the first
This is accomplished by the method shown in Figure 1. Therefore, capacitor 11
9 consists of a plurality of dense sintered ceramic dielectric thin layers with intervening thin films of metal, ie, thin layers 130 and 131, forming internal electrodes.

As shown, the discontinuous insulating regions or areas 132 within electrode 130 are vertically centered and
The insulation area within electrode 1 also has the same center line, but electrode 1
The insulating regions within 30 are laterally spaced apart from each other. Therefore, the lead wires 121 inserted through the holes 120 are electrically connected to the electrodes 130 within the capacitor, but are not connected to the electrodes 131 that alternately overlap the electrodes 130. Similarly, lead wire 122 is electrically connected only to electrode 131 internally.
The holes 120 are preferably formed in the green body by drilling or stamping before firing, but may also be punched after the ceramic body is fired. Typically, holes will not be present in the lamina 125 and membrane 126 prior to assembly, but for convenience of illustration, the hole location is indicated by reference numeral 120a in FIG. 17. The dimensions of the unitary capacitor may vary over a wide range.

In addition to varying the dimensions of the capacitor, the number and thickness of the thin dielectric layers and electrodes therein may be varied as well. It is often preferred that the thin dielectric layer be thicker than the thin conductive film, ie, the electrode, but this may vary as desired. 2. having two thin dielectric layers with a thickness of approximately 0.03 mm and one inner electrode with a thickness of approximately 0.0025 W01 L;
``It is easy to manufacture a capacitor of ×3.0 × 0.9w0n, and of course it is possible to manufacture a capacitor of larger dimensions. A capacitor with a given capacitance is obtained by appropriate selection of dielectric material, dimensions, thickness and number of thin layers and electrodes. The thickness and additional mechanical strength of the capacitor may be adjusted by adding thin layers or films on the top or bottom of the green ceramic structure. Unprinted thin films of dielectric ceramic compositions may be used for this purpose. However, the presence of thermally burnable deposits on the top dielectric thin film or thin films of such laminates is usually not harmful. Generally, it is preferred that the thin dielectric layers and electrodes be as thin as possible.

This is because less expensive dielectric material is used, the capacitor has a higher capacitance per unit volume, and therefore less space is required in the circuit. The thickness of the thin dielectric layer is determined to make such thin layer dense, non-porous, and able to withstand the applied voltage. Irregularities in the surface or thickness of thin films of dielectric material create problems in the formation of capacitors using very thin thin films of pseudoconductor. The reason for this is that such irregularities become clogged after firing, but it is generally preferable to make the electrodes, ie, the conductive thin film, thinner than the dielectric thin layer. The dimensions of the leads that pass through the holes in the single sintered ceramic body according to the invention may vary over a wide range.

Generally, it is preferred to use a lead wire having a diameter of about 0.25W0fL to about 0.65Tsn. However, thicker or thinner conductors may be used for convenience or need. Accordingly, in capacitors made with the ceramic structures shown in FIGS. 9 and 10, the leads are generally low. This is because the ends are flattened and substantially connect with the metal thin film within the capacitor. In large-sized capacitors, the lead wire may be a bar or the like as required. The diameter of the lead wire hole in the fired ceramic unit is slightly larger than the lead wire. in general,
In order to ensure the connection between the lead wire and the metal forming the internal electrode, it is preferable to cover the lead wire with molten electrode metal.
Copper is often good, but other metals can also be used. The capacitors described and illustrated so far have been rectangular.

However, it is also possible to manufacture capacitors of other shapes. Therefore, if it has multiple sets of independent electrodes, and each set has two or more protruding lead wires electrically connected to the electrodes, it can be shaped into a triangular, hexagonal, or oval shape as required. or any other desired shape. The single sintered ceramic body according to the invention may use in the form of dielectric thin layers any ceramic composition suitable for the production of such thin layers as described in the previously mentioned US patents; and the electrode regions (spatial regions) therein may be fabricated using any suitable composition described in the aforementioned patents.

However, other suitable compositions may be used if desired. Preferably, the composition forming the dielectric film comprises a finely divided ceramic material that forms a solid ceramic body that can be sintered. They also preferably contain a thermally incinerable temporary binder. The thin film used to form the temporary conductor within the green body may be formed of any of the compositions described in the above-referenced US patents or other suitable compositions, as previously described. Preferably, such a temporary conductor thin film is made of a thermally incinerating material. In any case,
The space occupied by the temporary conductor, after firing the ceramic body,
It forms a spatial region, which is at least about 40% empty and is filled with molten metal to form an electrode. As used herein, the term dense means that the material does not actually absorb water when immersed in water, and thin is a relative term; for example, for a thin ceramic layer, 0. Indicates 5w0n or less.

However, such thin layers may also be thicker for specific purposes. One-thermal incineration includes substances that vaporize under the conditions described herein, or that are oxidized or transformed into vaporized substances without being oxidized.

The method of forming a multilayer ceramic capacitor using the sintered ceramic body of the present invention can also be easily used to manufacture multilayer ceramic circuit boards.

FIGS. 20 and 21 show such a laminated ceramic circuit board for reference.

Circuit board 135 is comprised of three thin dielectric or insulating ceramic layers 136 that are sintered together to form a ceramic structure. Within this structure there are three internal conductors 137, 138, 139, preferably made of metal. Lead wires 140, 141, 142, 143 and 1
44 is arranged to extend from the exterior of the circuit board to one or more internal conductors (in the illustrated example, internal electrode 137
and 138), with thin ceramic layers on the upper and lower sides of the inner conductor. Lamina 136 is sintered together around and between the conductors, as well as around their edges.
In forming circuit board 135, essentially the same methods as described above for forming capacitors can be used. for example,
Three sheets of finely divided dielectric or insulating ceramic material temporarily bonded with resin are assembled and secured together with a temporary conductor film between the sheets at the locations where internal conductors are required.
Such a temporary conductor, or thin layer, may be formed using the capacitor manufacturing method shown in FIGS. 17-19, and is preferably comprised of a thermally incinerated material. Holes for lead wires and metal introduction are made in the green body that is formed.
For example, it can be provided by perforation or stamping. Such holes pass through the top and bottom ceramic thin layers 136 and communicate with or penetrate one or more temporary conductors. When firing,
The temporary conductor thin layer is incinerated and the thin sheets of ceramic material are sintered to form a unitary ceramic structure into which molten metal is introduced to form the internal electrodes. Molten metal is introduced into such regions via holes through the top or bottom ceramic lamina in the same manner as previously described. As in the capacitor manufacturing method described above, a bar or a lead wire may be inserted into the hole before introducing the molten metal, and this introduction may be carried out using the apparatus shown in FIG. The shape of the lead may vary, and the lead may be placed into or through one or more internal electrodes. The leads may be bent or tapered within the circuit board as shown at 146. As with capacitor manufacturing,
The cross section of the lead wire or rod is made slightly smaller than the hole into which it is inserted, and molten metal is injected from around it to form internal electrodes. Various metals and alloys may be used, but must have a melting point lower than the sintering temperature of the structure and the melting point of the lead wire.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a multilayer ceramic capacitor using a single sintered ceramic body according to the present invention, FIG. 2 is a top plan view of a modified example of a similar multilayer ceramic capacitor, and FIG.
Figure 4 is a partial vertical cross-sectional view taken along line 4-4 in Figure 1; Figure 5 is a partial vertical cross-sectional view similar to Figure 4 showing a modified lead wire arrangement. , Fig. 6 is a partial vertical sectional view of a ceramic body for forming a multilayer capacitor before insertion of lead wires and introduction of metal into the ceramic body, and Fig. 7 is similar to Fig. 6 showing a reference example using end face members. 8 is a partial vertical sectional view similar to FIG. 6 showing a modified arrangement of the lead wire holes; FIG. 9 is a reference example of the arrangement for attaching the lead wire to the sintered ceramic body. FIG. 10 is a partial side view taken along line 10-10 of FIG. 9 with the lead wires removed; FIG. 11 shows a method of supporting a ceramic body and introducing metal into its electrode area. 12 is a side view of a multilayer capacitor mounted on solder on a circuit board (shown in cross section), FIG. 13 is a top plan view of the structure shown in FIG. 12, and FIG. Figure 15 is a partial cross-sectional view showing a method of sealing the capacitor leads, and Figure 16 is a full view. FIG. 17 is an enlarged perspective view showing another modified example using the sintered ceramic body of the present invention, and FIG. 18 is a partial cross-sectional view showing an encapsulated multilayer capacitor; FIG. 18-18 in Figure 17 of the multilayer capacitor
19 is a vertical sectional view taken along line 19-19 of FIG. 18; FIG. 20 is a vertical sectional view taken along line 20-20 of FIG. 21 is a vertical sectional view taken along the line 21-21 in FIG. 20. 21, 22... Electrode (metal thin layer) 23... Side surface, 2
4... Other side of the capacitor, 25, 26... Lead wire, 28... Bent part, 29... Knot, 31...
Vertical hole portion, 33, 35... Electrode area, 39... Container (closed body), 40... Container, 42... Support rod portion, 4
3...Spring clip, 44...Lead wire, 4
7, 48... Hole portion, 49, 50... Electrode area, 52...
... Single sintered ceramic, 53... Thin layer, 54...
- Cavity part, 55, 56... Electrode area, 57... Flat end part, 58... Bar material (conducting wire), 59... Capacitor, 60, 61... Electrode, 62, 64... ··Lead,
63... Thin layer, 69... Substrate, 70, 71... Solder, 72, 73... Conductor, 74... Capacitor, 75
, 76... Lead wire, 81... Capacitor, 82...
・・Circuit board, 83, 84 ・Lead wire, 85, 86・
... hole, 87, 88 ... conductor, 91 ... sealing composition, 92 ... lead wire, 93 ... capacitor, 95
...Capacitor, 96...Coating, 97,98...
Lead wire, 103...Ceramic structure, 104...
・Thin layer, 105, 106... Spatial region, 107...
Structure end face, 109... End face member, 111... Hole, 119... Multilayer capacitor, 120... Vertical hole, 121, 122... Lead wire (lead bar), 12
5...Thin plate, 126...Temporary conductor thin film, 127...
- Opening, 129... Dielectric ceramic thin layer, 130
, 131... Electrode, 135... Circuit board.

Claims (1)

[Scope of Claims] 1. A large number of superimposed dense ceramic dielectric thin layers, a thin spatial region existing between these thin layers, and a dielectric ceramic outer wall covering the entire outer periphery of these spatial regions; a first vertical hole passing through the plurality of thin layers of dense ceramic dielectric and passing through every other spatial region but not communicating with every other remaining spatial region; a second longitudinal hole passing through a thin layer of ceramic dielectric and passing through every other spatial region of said remaining but not communicating with said first every other spatial region. Single sintered ceramic body. 2. A unitary sintered ceramic body according to claim 1, characterized in that the spatial region is thinner than the ceramic thin layer adjacent thereto. 3. A single sintered ceramic body according to claim 2, characterized in that the thickness of the spatial region is 0.00254 mm. 4. Within each spatial region there is an insulating region 132 made of a dense ceramic material integral with the adjacent ceramic thin layer, and one of the pair of holes is located in every other insulating region 132.
2. A single sintered ceramic body according to claim 1, wherein the single sintered ceramic body passes through one of the two remaining insulation regions. 5 Forming a plurality of thin plates from a finely ground sinterable dielectric, ceramic material, applying a heat-combustible material in a smaller area to the thin plates, and applying each coated thin plate between adjacent ceramic thin plates. Layers of heat-combustible material are sandwiched and overlapped, and the entire outer periphery of these layers of heat-combustible material is sealed with a dielectric ceramic material to form a green ceramic laminate, and the ceramic laminate is penetrated vertically. a pair of spaced apart holes, the first hole passing through every other layer of thermally incinerable material but spaced apart from the remaining every other layer of thermally incinerable material; are drilled through said remaining every other layer of thermally inflammable material but spaced apart from said first every other layer of thermally inflammable material, and then 110
A method for manufacturing a single sintered ceramic body for a laminated ceramic capacitor, characterized in that a space region is formed by firing and removing the heat-combustible material layer in an oxidizing atmosphere at a temperature of 0°C or higher. 6. A method according to claim 5, characterized in that the heat-combustible material is applied onto the thin plate to a thickness thinner than the thin plate. 7. An insulating region 132 made of the same material as the thin plate is provided in each heat-incinerating material layer, and a pair of holes are formed, one of which penetrates every other insulating region 132 and the other of which penetrates every other insulating region 132. 6. The method according to claim 5, characterized in that the method comprises drilling a hole through the hole.