WO2012028659A2

WO2012028659A2 - Ceramic component and method for producing a ceramic component

Info

Publication number: WO2012028659A2
Application number: PCT/EP2011/065049
Authority: WO
Inventors: Thomas Feichtinger; Günter PUDMICH
Original assignee: Epcos Ag
Priority date: 2010-09-03
Filing date: 2011-08-31
Publication date: 2012-03-08
Also published as: CN103210456A; CN103210456B; EP2612333B1; DE102010036270A1; WO2012028659A3; DE102010036270B4; JP5716092B2; EP2612333A2; JP2013536989A

Abstract

A ceramic component (100) comprises a basic body (101) with two connecting contacts (102, 103) fitted thereon. The component (100) has a first longitudinally extended via electrode (104) and a second longitudinally extended via electrode (105), said electrodes each being coupled to one of the connecting contacts (102, 103). The first via electrode (104) and the second via electrode (105) each have an extended area (106, 107) in projection in the longitudinal direction. For production purposes, a plurality of ceramic layers (117, 118, 119) is layered to form a layer stack, which forms the basic body (101), and the two via electrodes (104, 105) are introduced into the layer stack transversely to the layer sequence.

Description

description

Ceramic component and method for producing a ceramic component

Field of the invention

The invention relates to a ceramic component, as in ^¬ example, a varistor, and a method for producing such a device.

Background of the invention

Varistors may be used to protect RF circuits from damage by electrostatic discharge. In such an electronic component, the resistance is voltage-dependent and is abruptly above a certain threshold voltage smaller. As a result, charge can be discharged at a high applied voltage across the varistor.

Conventional multilayer varistors have outer terminal ^¬ contacts, of which comb-like internal electrodes extend into the ceramic base body. Such a multilayer varistor is shown, for example, in DE19931056.

The capacity of such a component can not be arbitrarily re ^¬ duced, since in particular the external electrodes contribute to a ceramic base body with a high dielectric constant to a relatively high total capacitance value. Furthermore, the accuracy in the application of the comb-like internal electrodes, for example by means of a screen ^¬ printing process, limited, whereby tolerances in the capacitive Did the components arise. This also applies, for example, to process-related fluctuations of the individual layers of the ceramic base body, which are, for example, ceramic foils.

It is desirable to provide a ceramic component that has a low capacity and can be compensated at the herstel ^¬ lung-related tolerances. Furthermore, it is desirable to specify a method for producing such a ceramic component.

In one embodiment of the invention, a ceramic component comprises a main body with two connection contacts attached thereto. The ceramic component further comprises a first and a second elongate via electrode, which are each coupled to one of the terminal contacts. The first and second via electrodes each have an extended area when projected in the longitudinal direction.

By contacting an inner portion of the ceramic component by means of via-electrodes, it is possible, the capacity of the ceramic component is very small einzustel ^¬ len. In particular, the ceramic component a Kapa ^¬ capacity to <3 pF.

In embodiments, the projection of the first via electrode and the projection of the second via electrode each overlap in the longitudinal direction on a common projection plane. In particular, the part of the projection in which the projections overlap is larger than a part where the projections do not overlap. In other embodiments, the area of the projection is the first one Via electrode on the common pro ektionsebene smaller than the area of the projection of the second via electrode. The projection of the first via electrode is arranged on the projection ^¬ plane within the projection of the second Via-electrode at ^¬. Thus manufacturing tolerances can be ausgegli ^¬ chen.

In one embodiment of the invention, a method for producing a ceramic component comprises layers of a plurality of ceramic layers to form a layer stack which forms a base body of the ceramic component. Two via electrodes are introduced transversely to the layer sequence from two opposite sides of the layer stack into the layer stack. Two connection contacts are attached to the layer stack, so that the connection contacts are each electrically coupled to one of the via electrodes. In embodiments, recesses are punched into the layer stack for insertion of the via electrodes and filled with an electrically conductive material.

Thus, a ceramic component can be produced, which has a low capacitance and can be compensated in the manufacture- ^related tolerances.

Brief description of the drawings

Further advantages, features and developments emerge from the following, explained in conjunction with the figures examples. The same, similar and equally acting elements may be provided in the figures with the same reference numerals. The illustrated elements and their proportions to each other are basically not to be regarded as appropriate ^¬ stabsgerecht, but individual elements, such as layers or areas, for better representability and / or for better understanding to be shown exaggerated thick or large dimensions.

Show it:

1A and 1B is a schematic representation of a kera ^¬ mixing device according to an embodiment,

Figure 2 is a schematic representation of a ceramic

Component according to another embodiment,

Figure 3 is a schematic representation of a ceramic

Component according to another embodiment,

Figures 4A and 4B is a schematic representation of a Kera ^¬ mixing device according to one embodiment,

Figures 5A and 5B is a schematic representation of a Kera ^¬ mixing device according to one embodiment,

Figure 6 is a schematic representation of a ceramic

Component according to one embodiment,

FIG. 7 shows a schematic perspective view of a ceramic component in perspective view according to an embodiment,

Figure 8 is a schematic representation of a ceramic

Component with four terminals, and Figure 9 is a schematic representation of a ceramic

Component with eight connection contacts according to an imple mentation form.

Detailed description of embodiments

FIG. 1A shows a ceramic component 100 in a cross- ^sectional view. The ceramic component has a base ^¬ body 101, which is constructed of ceramic layers. On two opposite side surfaces 126, 127 in each case a connection contact 102, 103 for electronic contacting of the device 100 is attached. Starting at the sides ^¬ surface 126, a longitudinally extended viaducts electrode 104 into the main body 101 extends starting from the side surface 127 extends a further Via-electrode 105 into the main body 101. The via electrodes extend to an active region 125 in which, for example, a varistor ceramic is arranged. The via electrodes 104 and 105 each have at the end which faces away relationship ^¬ example 103 the connection contact 102 to which they are electrically coupled, a transversely extended to the longitudinal direction of surface 106 be ^¬ relationship as 107.

The ceramic layers of the main body 101 are arranged in a layer stack. The layers are extended flat in the Y direction of Figure 1 and stacked in the X direction of Figure 1. The layers are arranged transversely to the planar extent of the connection contacts 102, 103 on each other. The via electrodes 104 and 105 extend transversely to the stacking direction of the layer stack. The via electrodes 104 and 105 penetrate a plurality of ceramic layers, in particular more than two ceramic layers. FIG. 1B shows a sectional view of the component of FIG. 1A along the plane A - A '. The surface 106 and the surface 107 have in projection in the longitudinal direction of the via electrodes on a Pro ektionsebene, for example, the plane A - A ', an overlapping area. Preferably, the projections completely overlap, as shown in FIG. 1B. A diameter 115 of the via electrode 104 and the via electrode 105 transverse to the longitudinal propagation is the same size.

The surface area of the projection on the projection plane of the two via electrodes 104 and 105 is the same size in the illustrated embodiment. For example, the area ^¬ content of the projection of the via-electrodes 104 and 105 each approximately between 3500 μπι ² and 6500 μπι ^second If the projection has a circular shape, this corresponds to a diameter of about 65 μπι to about 90 μπι.

The projection of the via electrodes is circular in each case when the via electrodes 104 and 105, for example, a

Have circular cylindrical shape. The top and top surfaces of the cylindrical shape correspond to the surface 106 of the via electrode 104 and the surface of the via electrode facing the terminal contact 102. The via electrodes have ^¬ form a circular cylinder shape in execution, but they can also have other shapes such as an elliptical base area or ^¬ a rectangular base.

The relevant for the electrical function of the ceramic component, in particular the varistor function, Be ^¬ rich 125 is disposed between the surfaces 106 and 107 of the via electrodes 104 and 105. This allows the tolerance ranges, for example, the capacitance of the device, ver ^¬ be downsized and hang example, substantially only still from a variation of the distance between the surface 106 and 107 from.

The via electrodes are introduced into the layer stack after the ceramic layers have been stacked. For example, the via electrodes are punched into the layer stack and then filled with an electroconducting ^¬ ELIGIBLE material, such as a paste.

Figure 2 shows a further embodiment of the Bauele ^¬ ments 100. In contrast to the illustration of FIGS 1A and 1B show the via electrodes 104 and 105 to each other have different diameters 115 and 116 on. In projek ^¬ tion in the longitudinal direction of the surface area of the Via-electrode 105 is larger than the area of the via electrode 104. Before ^¬ preferably are the two Via electrodes are coaxial. Insbesonde ^¬ re is the projection with the smaller surface area fully ^¬ constantly within the projection having the larger surface area. At least the overlapping portion of the two projections is larger than the portion that does not overlap.

Since the electrode 105 is extended transversely to the longitudinal propagation direction more than the Via-electrode 104, Auswir ^¬ fluctuations are reduced on the electrical properties of the device that occur from shifts in the Via-electrodes relative to each other. Even with a relative displacement transversely to the longitudinal propagation direction of the two via electrodes 104 and 105, the projection of the via electrode 104 in the longitudinal direction is within the projection of the via electrode 105. The capacitive properties of the component are thereby primarily by the via electrode 104 determined with the smaller extent transverse to the longitudinal direction. FIG. 3 shows a further embodiment of the component 100. In contrast to the previous figures, the component 100 has a further via electrode 108, which is arranged between the via electrode 104 and the via electrode 105. The additional via electrode 108 is preferably arranged co ^¬ axially to the via electrodes 104 and 105. In Pro ^¬ jection in the longitudinal direction of propagation of the via electrodes, the projections of the three via-electrodes 104, 105 and 108 overlap, preferably completely. Between the surface 106 of the via electrode 104 and an opposite surface 109 of the via electrode 108, a varistor ceramic is arranged. Between the surface 107 of the via electrode 105 and a gege ^¬ nüberliegenden surface 110 of the Via-electrode 108 is a white ^¬ tere layer comprising a varistor disposed.

The arrangement of two active regions, one between via electrode 104 and via electrode 108 and one between via electrode 108 and via electrode 105, in series reduces the capacitance of the device.

FIGS. 4A and 4B show a further embodiment of the component 100, in which, in contrast to the previous exemplary embodiments, two via electrodes each are coupled to one of the connection contacts. With the Anschlusskon ^¬ clock 102, the via electrode 104 and another via electrode 111 is electrically coupled. With the terminal contact 103, the via electrode 105 and another via electrode 112 is electrically coupled.

The via electrodes 104 and 111 or 105 and 112 are rectilinear, preferably parallel, starting at the respective terminal contacts in the longitudinal direction into the interior of the main body 101 to the active area. FIG. 4B shows a sectional view along the plane A - A 'of FIG. 4A. Dashed lines show the projection of the via electrodes 105 and 112 on the plane A - A '. The projection of the via electrodes 104 and 112 surround the cross-section of the via electrode 104 and the electrode 111. The viaducts projections of the via electrodes 104 and 105 or 111 and 112 overlap each full ^¬ constantly. The projections of the via electrodes 104 and 111, respectively, which have the smaller surface area, are each completely arranged within the projections of the via electrodes 104 and 111, respectively.

FIGS. 5A and 5B show a further embodiment of the component 100, in which the base body comprises materials with mutually different dielectric constants.

A region 117 of the base body 101, which faces the connection contact 102 and with this a common Kon ^¬ clock face (side face 126), has a lower dielectric constant than an area 118 of the main body 101, which the in the direction away from the terminal contact 102 to Section 117 connects. In an area 119 of the main body 101, facing the terminal contact 103, and has with the ^¬ sem a common contact surface (side surface 127) on ^¬, in turn, has a lower dielectric constant than the portion 118, preferably the same dielectric constant as the area 117th A material 120 of the regions 117 and 119 has the lower dielectric constant than a material 121 of the region 118. For example, the region 117 or the region 119 has a relative permittivity of approximately ε _Γ = 5. The lower the dielectric constant of the regions 117 and 119, the lower the Ka capacity of Bautelements through the connection contacts. The ^regions 117, 118 and 119 can each be formed from a plurality of ceramic layers. The ceramic

Layers of the regions 117, 118 and 119 are stacked across the longitudinal direction of the via electrodes.

By the use of materials of different dielectric constant in the areas 117 and 119, which adjoin the terminal contacts, and in the area 118, in which the active area 125 and the end surfaces 106 and 107 of the via electrodes 104 and 105 are located Device 100 has a low capacity, in particular a capacity of <5 pF, preferably a capacity <3 pF. Since the viaducts electrodes 104 and 105 are surrounded in the areas 117 and 119 of the material 120, which has a low dielectric ^¬ figure, stray electrical effects from the preparation ^¬ surfaces 117 and 119 can be reduced. In order to reduce a chemical Reakti ^¬ on between layers of high and low dielectric constant, preferably to prevent, the area 118 is made thicker. In particular, a part of the via electrodes is arranged in the region 118.

FIG. 5B shows a sectional view along the plane A - A 'of FIG. 5A. Along the plane A - A ', the via electrode 105 is surrounded by the material 120 having the comparatively low dielectric constant.

Figure 6 shows a further embodiment of the Bauele ^¬ ments 100 in which the via electrodes 104 and 105 respectively along their longitudinal propagation direction transverse to Längsaubrei- power direction have different dimensions. In the areas 117 and 119 that are adjacent to the terminals 102 be ^¬ relationship as 103, has a range of 123 Via- Electrode 105, which is surrounded by the material 120, a greater extent transverse to the longitudinal propagation, as in the subsequent region 124 of the via electrode 105. In particular, the region 124 has the diameter 115 and the region 123 has a diameter 122, the larger is as the

Diameter 115.

Through the area 123 of the via electrode 104 and the via electrode 105, which has a comparatively large Ausdeh ^¬ voltage, the via electrodes 104 and 105 are well e lectric coupled to the respective connecting contacts 102 and 103rd For shielding and to keep the capacity of the device low, the preparation ^¬ surface 123 are arranged in the material 120. In the region 118 with the material 121, which has a higher dielectric constant than the material 120, the via electrodes are formed with a smaller cross section than in the regions 123.

FIG. 7 shows the component 100 in a perspective view. The component has, for example, zirconium oxide, ZnO-BI and / or ZnO-PR as varistor ceramics. In other embodiments, the component may comprise capacitor materials, in particular C0G, X7R, Z5U, Y5V and / or HQM.

FIG. 8 shows a further embodiment of the component 100 in a perspective view, in which four connection contacts are arranged on the main body 101. On the Be ^¬ th surface 127 of the main body 101 two Anschlußkontak ^¬ te 103 are arranged. On the opposite side surface 126 two connection contacts 102 are arranged. Depending Anschlusskon clock ^¬ a via-electrode extends in the direction of gege ^¬ nüberliegenden contact pad by a portion of the base ^¬ body. The device 100 according to the embodiment of the invention For example, gur 8 has a device area of <5.12 mm ² , preferably a device area of 2.5 mm ² .

Figure 9 shows the device 100 according to another embodiment with eight connection contacts 102 and 103. The side face 126 and 127 are four contacts arranged on ^¬ circuit 102 and 103rd Depending on ^¬ circuit contact, a via-electrode extends into the interior of the base body 101. shapes guiding In further from each extend terminal contact several Via-electrodes in ^¬ play, two Via-electrodes into the interior of the base body 101. The device 100 according to the Off 9 has, for example, a device area of <8 mm ² , in particular a device area of 5.12 mm ² .

From the guide of Figures 8 and 9 are forms varistor arrays formed, which comprise a plurality of individual Varisto ^¬ ren.

The invention is not limited by the description based on the embodiments of these. Rather, the invention encompasses every new feature as well as every combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination itself is not explicitly stated in the patent claims or exemplary embodiments.

Claims

claims

A ceramic component comprising:

a base body (101) with two connection contacts (102, 103) attached thereto,

- a first (104) and a second (105) elongated stretched out ^¬ Via-electrode corresponding to the coupled to ^¬-circuit contacts (102, 103) respectively with one,

- wherein the first (104) and second (105) via electrodes each have an extended area (106, 107) in longitudinal projection.

2. Ceramic component according to claim 1, wherein the projection of the first via electrode (104) and the projection of the second Via-electrode (105) at least partially ^¬ partially overlap.

3. A ceramic device according to claim 1 or 2, wherein the surfaces (106, 107) of the projections are the same size.

4. A ceramic device according to claim 1 or 2, wherein the area (106) of the projection of the first via electrode (104) is smaller than the area (107) of the projection of the second via electrode (105).

5. A ceramic device according to any one of claims 1 to 4, wherein the first (104) and second (105) via electrode each have a cylinder shape.

6. Ceramic component according to one of claims 1 to 5, wherein one of the via electrodes (104, 105) has a first region (123) with a first diameter (122) and a NEN second region (124) having a first diameter (122) different second diameter (115).

7. Ceramic component according to one of claims 1 to 6, wherein the base body (101) has two regions (117, 118) which have mutually different dielectric numbers.

8. The ceramic component according to claim 7, wherein each of the terminal contacts (102, 103) facing region (117, 119) of the Grundköpers (101) has a lower dielectric constant than the region (118), between each of the terminal contacts (102, 103) facing regions (117, 119) is arranged.

9. The ceramic component according to claim 8, as far as dependent on claim 6, wherein the first diameter (122) is greater than the second diameter (115) and wherein the first region (123) of the via electrode (104, 105 ) surrounding the region (117, 119) of the base body (101) having the lower dielectric constant.

10. Ceramic component according to one of claims 1 to 9, wherein between the terminal contacts (102, 103) facing away from the first ends of the first (104) and the second (105) via electrode, a further via electrode (108) angeord ^¬ net is.

11. A ceramic device according to any one of claims 1 to 10, wherein between the first (104) and the second (105) Via a varistor ceramic (125) angeord ^¬ net is.

12. A method of making a ceramic device, comprising:

- Layers of a plurality of ceramic layers (117, 118, 119) to form a layer stack, which forms a base body (101) of the ceramic component,

- introducing two Via electrodes (104, 105) in the layer stack transversely to the layer sequence of two gegenü ^¬ berliegenden sides of the layer stack,

- Attaching two connection contacts (102, 103) to the layer stack, so that the connection contacts (102, 103) each with one of the via-electrodes (104, 105) e- lektrische are coupled.

13. The method of claim 12, wherein the introduction of the via electrodes (104, 105) comprises:

- each punching recesses in the layer stack (101),

- Fill the recesses with an electrically conductive material.