WO2009146987A1

WO2009146987A1 - Contact structure, electronic component comprising a contact structure and method for the manufacture thereof

Info

Publication number: WO2009146987A1
Application number: PCT/EP2009/055186
Authority: WO
Inventors: Carsten Schuh
Original assignee: Continental Automotive Gmbh
Priority date: 2008-06-06
Filing date: 2009-04-29
Publication date: 2009-12-10
Also published as: DE102008027115A1

Abstract

A contact structure (8; 8') of an electronic component (1) having a ceramic body (7) and at least one internal electrode (2) is provided. A first surface (6) of the component (1) comprises an electrically insulating layer (15) with at least one penetration (16) that reveals at least part of the internal electrode (2). The contact structure (8, 8') comprises a first electrically conducting layer (18; 18') made of electrically conducting nanoscale grains, said grains being disposed in the penetration (16) and connected to the internal electrode (2) located therein. Moreover, the contact structure comprises a second electrically conducting contact layer (19) that is disposed on the first electrically conducting layer (18).

Description

description

Contact structure, electronic component with a contact structure and method for its production

The invention relates to a contact structure, an electronic component with a contact structure and a method for producing a contact structure and an electronic component.

Electronic components with a ceramic body and at least one metallic inner electrode, such as piezo actuators, are known, for example, from DE 10 2006 003 070 B3.

These electronic components typically have large-area metallic external contacts, which are arranged at least partially on the ceramic body of the component and are in electrical connection with the internal electrodes.

Due to the different materials, cracks may form between the ceramic body and the external contacts and / or within the contact structure. Piezoelectrically active components are susceptible to cracking due to the mechanical deformation of the piezoelectrically active ceramic, since this mechanical deformation can lead to additional stress on the external contacts.

The object of the invention is therefore to provide a contact structure for an electronic component with a ceramic body and at least one inner electrode, which is more reliable. Furthermore, it is an object of the invention to provide an To provide nischer component with a contact structure that is more reliable.

This is solved by the subject matter of the independent claims. Advantageous developments are the subject of the respective dependent claims.

According to the invention, a contact structure of an electronic component with a ceramic body and at least one inner electrode is provided. The inner electrode is disposed in the ceramic body and extends to a first surface of the device where it forms a portion of the first surface of the device. The first surface of the component has an electrically insulating layer with at least one through opening, which exposes at least a part of the inner electrode. According to the invention, the contact structure has a first electrically conductive layer of electrically conductive nanoscale grains and a second electrically conductive contact layer. The first electrically conductive layer is arranged in the through opening of the electrically insulating layer and is electrically connected to the inner electrode arranged in the through opening. The second electrically conductive contact layer is arranged on the first electrically conductive layer and electrically connected to the inner electrode.

The contact structure according to the invention thus has two layers. The lower first electrically conductive layer is in direct contact with the inner electrode and is formed from nanoscale grains. The term nanoscale is used herein to refer to grains having an average diameter of 1 nm to 100 nm, preferably from 1 nm to 200 nm. This lower electrically conductive layer forms an improved electrical connection with the inner electrode, because the diameter of the nanoscale grains is substantially smaller than the thickness or exposed surface of the inner electrode that forms a portion of the first surface of the device.

Typically, the thickness of the inner electrode is about a few micrometers, for example 2 to 3 micrometers (μm). Consequently, an electrical connection between a plurality of nanoscale grains of the first electrically conductive layer and the inner electrode is generated over the thickness of the inner electrode layer. With increasingly smaller grains, the contact area between the first electrically conductive layer and the inner electrode is increased. This increased contact area between the contact structure and the inner electrode leads to a reliable electrical connection even under mechanical stress of the contact structure.

The second electrically conductive contact layer can also have nanoscale grains, but also larger grains, i. do not have nanoscale grains. The second electrically conductive contact layer may be made of a known material as well as a known method. By inserting some additional steps for applying the first layer of nanoscale grains, the contact structure according to the invention can be integrated into a known production method. The manufacturing costs can be kept low.

The second electrically conductive contact layer may be formed from a conductive adhesive or may be an electrodeposited metal or an alloy.

The nanoscale grains of the first electrically conductive layer can be made of a metal or an alloy. hen, which has a good electrical conductivity. In one embodiment, the electrically conductive nanoscale grains include one or more of Ag, Au, Cu, Ni, Cr, Pt, Pd, Ti, and W.

The first electrically conductive layer is formed in one embodiment of wet-chemically applied nanoscale particles. This structure has the advantage that preformed nanoscale particles can be used, which are commercially available. The particles may be applied as a suspension in a vaporizable solution or as a mixture with a binder. The applied mixture may be thermally treated to remove the solution or binder and then form a layer of nanoscale sintered grains. This sintered layer may be macroscopically electrically conductive.

The first electrically conductive layer can also advantageously be a bonding agent in order to further increase the reliability of the contact structure. The material of nanoscale

Grains as well as the material of the inner electrode can be selected so that they chemically react or alloy together to produce a mechanically reliable and electrically conductive connection. In this exemplary embodiment, the boundary between the first electrically conductive layer and the inner electrode has phases comprising the material of the inner electrode and the material of the nanoscale grains.

The first surface of the electronic component has an electrically insulating layer with at least one through opening which exposes at least part of the inner electrode in order to ensure electrical contact between the first and the second electrically conductive layer and the inner electrode. electrode, which is arranged in the ceramic body, to ensure. In one exemplary embodiment, a plurality of strip-shaped openings are provided in the electrically insulating layer, which each expose a strip-shaped surface of an inner electrode.

The strip-shaped openings can expose the entire length of the inner electrode. A larger opening has the advantage that the contact area between the inner electrode and the contact structure increases and the electrical resistance of the contact between the inner electrode and the contact structure is reduced. At the same time, the reliability of the connection can be improved because the mechanical strength of the connection is increased.

In one embodiment, the first electrically conductive layer is disposed entirely within the through opening or openings. The thickness of the first electrically conductive layer is smaller than the thickness of the electrically insulating layer. The first electrically conductive layer is provided in this embodiment as a limited area or a plurality of separate limited areas, which are electrically insulated from one another in their position over regions of the electrically insulating layer. The regions of the first electrically conductive layer are electrically connected to one another only via the second electrically conductive contact layer.

In one embodiment, the first electrically conductive layer is further arranged on the electrically insulating layer. In this embodiment, the first electrically conductive layer is disposed not only within the through holes but also adjacent to the through holes. The first electrically conductive layer may have several exposed ones Internal electrode of the surface electrically connect to each other when it extends over a plurality of exposed internal electrodes. The first electrically conductive layer of nanoscale grains can thus be a closed layer on the surface of the component.

In a further embodiment, a protective layer is further arranged on the second electrically conductive contact layer. The protective layer can increase the service life of the component during operation, since the contamination of the contact structure is prevented by the operating conditions. In particular, when using the device as a piezoelectric actuator, the device can come into physical contact with the substance to be switched, for example diesel or gasoline in an injection valve. This material can be corrosive, so that the material of the protective layer is selected accordingly.

The protective layer can completely encase the component at the side surfaces, wherein contact surfaces of the collecting contacts are kept free, so that an external contact to the components can be produced. In further embodiments, the protective layer is electrically insulating and / or has plastic.

The first surface of the component has an electrically insulating layer, which in one exemplary embodiment is a further layer which is arranged on the ceramic component. This arrangement can be used when the inner electrode extends completely over the layers of the ceramic body, such as in a fully active multilayer piezoelectric actuator. In a further embodiment, the electrically insulating layer is formed from the ceramic body of the device. The ceramic body thus has openings in its surface, which exposes at least a portion of the inner electrode. This arrangement can be used when the inner electrode does not extend completely over the ceramic layer.

The invention also provides an electronic component with a contact structure according to one of the preceding embodiments. The electronic component has a ceramic body and at least one inner electrode which is arranged in the ceramic body, extends up to a first surface of the component and forms a region of the first surface of the component. The first surface of the electronic component has an electrically insulating layer with at least one through opening, which exposes at least a part of the inner electrode.

As already explained, the contact structure according to the invention has a first lower electrically conductive layer of electrically conductive nanoscale grains and a second upper electrically conductive contact layer. The first electrically conductive layer is arranged in the through opening of the electrically insulating layer and is electrically connected to the inner electrode arranged in the through opening. The second upper electrically conductive contact layer is disposed on the first lower electrically conductive layer and electrically connected to the inner electrode.

In one embodiment, the electronic device is a multilayer piezoelectric actuator having a plurality of piezoelectrically active layers and a plurality of electrically conductive inner electrode layers. The electrically conductive Inner electrode layers each provide an electrically conductive inner electrode. The piezoelectrically active layers and the electrically conductive inner electrode layers are alternately stacked on each other in a stacking direction. The first surface of the electronic component extends approximately perpendicular to the surface of the piezoelectrically active layers and the electrically conductive inner electrode layers and parallel to the stacking direction.

In one exemplary embodiment, every second inner electrode layer of the first surface is arranged in one of a plurality of through openings of the electrically insulating layer. The further inner electrode layers are covered by the electrically insulating layer on the first surface.

In a further development of this embodiment, the second electrically conductive contact layer electrically connects each other of the plurality of inner electrode layers of the first surface. The second electrically conductive contact layer provides a collecting contact that electrically connects each second one of the plurality of inner electrode layers exposed on the first surface in parallel.

In one development, the electronic component has a second surface, which is arranged opposite the first surface. This second surface has a contact structure according to one of the preceding embodiments.

If the first surface of the electronic component a

Variety of alternating piezoelectric layers and electrically conductive inner electrode layers and an electrically insulating layer having through openings, the second surface may also include a plurality of alternating piezoelectric see layers and electrically conductive inner electrode layers and having an electrically insulating layer with openings.

In this case, a through opening of the electrically insulating layer on the second surface exposes every second inner electrode layer of the second surface that is not electrically connected to the second electrically conductive contact layer on the first surface. Adjacent internal electrode layers of the stack are electrically connected to different contact layers. The two contact layers are electrically isolated from each other, so that a voltage between adjacent inner electrode layers of the multilayer piezoactuator can be applied to the contact layers.

These arrangements of the contact structure according to the invention in a multilayer piezoelectric actuator can be used when the piezoelectrically active layers are almost fully active, as well as when the piezoelectrically active layers do not have piezoelectrically active regions.

The invention also provides a method for contacting a ceramic component. First, a device with a ceramic body and at least one inner electrode is provided. The inner electrode is disposed in the ceramic body, extends to a first surface of the device and forms a portion of the first surface of the device. The first surface has an electrically insulating layer with at least one through opening, which exposes at least a part of the inner electrode. A first layer of electrically conductive nanoparticles is applied in the through opening. Thereafter, a second electrically conductive layer is applied to the first layer, wherein the inner electrode is electrically connected to the second layer via the first layer.

In one embodiment, the device has a plurality of piezoelectrically active layers and a plurality of electrically conductive inner electrode layers. The piezoelectrically active layers and the electrically conductive inner electrode layers are alternately stacked on each other in a stacking direction. In one development of this method, the electrically insulating layer is structured such that a through opening exposes every second inner electrode layer on the first upper side.

In this embodiment, the first electrically conductive layer is applied in the openings of the electrically insulating layer. The second electrically conductive layer is deposited on the first electrically conductive layer in the through holes, so that a plurality of internal electrodes, which are respectively exposed in one of the through openings, are electrically connected to one another and to the second contact layer.

If the component has a multiplicity of the alternating piezoelectrically active layers and electrically conductive inner electrode layers and a second surface which is arranged opposite the first surface, an electrically insulating layer with openings on the second surface is structured such that a through opening opens out every second inner electrode layer the second surface is not electrically connected to the second electrically conductive contact layer on the first surface. Each contact layer provides an electrical connection to a group of internal electrodes, the two groups of internal electrodes being electrically isolated from each other. The interior Electrode of each group is electrically connected in parallel at least over its second contact layer.

The internal electrodes forming part of the first surface are electrically connected to each other via the second contact layer disposed on the first surface. The internal electrodes, which form part of the second surface, are electrically connected to one another via the second contact layer, which is arranged on the second surface.

As with the first surface, a first layer of electrically conductive nanoparticles may be deposited in the apertures of the second surface. An upper second electrically conductive contact layer is deposited on the lower first electrically conductive layer of nanoscale grains on the second surface.

The nanoparticles from which the first layer is formed can be applied in a mixture with a solvent or in a mixture with one or more organic binders. Thereafter, the device may be thermally treated to remove the solvents or binders and to increase the electrical conductivity of the first layer.

An electrical and mechanical connection between the first layer and the inner electrode can be effected by a thermal treatment. An electrically conductive layer with nanoscale grains is formed from the applied nanoparticles.

An electrical connection between the first layer and the inner electrode exposed in the through-opening can by a chemical reaction or alloying of the first layer with the inner electrode. In this case, the first layer can simultaneously exert an adhesion-promoting effect.

The nanoparticles or the solvents or binders with nanoparticles can be applied by a screen printing method, spraying or dipping. In one embodiment, when the nanoparticles are applied in the through-opening, the electrically insulating layer can be used as a mask. This method can be used when the first layer is completely disposed within the apertures.

The second electrically conductive layer may be applied by spraying or dipping or screen printing.

In one exemplary embodiment, the electrically insulating layer is applied by spraying or dipping or by a screen printing method or by lamination of a film. If the electrically insulating layer is applied in the form of a closed layer, after the application of the electrically insulating layer, the electrically insulating layer can be patterned with laser ablation or a photolithographic method.

Embodiments of the invention will now be explained in more detail with reference to the drawings.

FIG. 1 shows a schematic view of a multilayer piezoactuator with a contact structure according to the invention, Figure 2 shows a schematic detailed view of a contact structure according to a first embodiment of the invention, and

Figure 3 shows a schematic detailed view of a contact structure according to a second embodiment of the invention.

FIG. 1 shows a multilayer piezoactuator 1 which has a multiplicity of internal electrode layers 2 and a multiplicity of piezoelectrically active layers 3. The multilayer piezoelectric actuator is used in this embodiment for use as an actuating element in injection valves of a motor vehicle engine. The inner electrode layers 2 and the piezoelectrically active layers 3 are alternately stacked on each other in a stacking direction 4 and form a multilayer body 7 of the multilayer piezoelectric actuator 1.

The inner electrode layers 2 each consist of an electrically conductive material, in particular a metal or an alloy such as Ag-Pd. The piezoelectrically active layers 3 are made of a material exhibiting the piezoelectric effect, i. When an electric field is applied, the material deforms mechanically. This mechanical deformation creates usable strain and / or force on the end surfaces so that the stack can be used as an actuator.

In this exemplary embodiment, the piezoelectrically active layers 3 consist of a ceramic, in particular PZT (lead zirconate titanate). The inner electrode layers 2 extend over the entire surface of the adjacent piezoelectrically active layers 3. This arrangement of the multilayer piezoelectric actuator 1 is referred to as a fully active piezoelectric actuator stack. In this arrangement, the internal electrodes 2 extend to the peripheral 5 pages of the stack and form there a part of the surface 6 of the body 7 of the piezoelectric actuator. 1

The piezoelectric actuator 1 further has a contact structure 8, with which an electrical contact to the respective internal electrodes 2 can be produced. A voltage is applied between the adjacent internal electrodes 2 of the stack, so that the piezoelectrically active layers 3 arranged between the internal electrodes 2 react mechanically. Each second inner electrode 2 is electrically connected to a common collecting contact 11, so that two groups of inner electrodes 9, 10 are provided, which are electrically insulated from each other. Adjacent internal electrodes 2, 2 'of the stack belong to different groups 9, 10.

A first collecting contact 11 is arranged on a first edge side 12 of the body 7 and a second collecting contact 13 on the opposite edge side 14 of the body 7, the first collecting contact 11 with the first group 9 of inner electrodes 2 and the second collecting contact 13 with the second group 10 of internal electrodes 2 'is electrically connected.

In order to avoid a short circuit between the two groups 9, 10 of internal electrodes 2, 2 'and between the two collecting contacts 11, 13, an electrically insulating layer 15 is provided on at least the two edge sides 12, 14 of the body 7 with the collecting contacts 11, 13 arranged.

The electrically insulating layer 15 has through openings 16 which expose the surface 17 of the inner electrode layers 2, which forms part of the first surface 6 of the body 7. In particular, the openings 16 in the electrically insulating layer 15 define the first group 9 of internal electrodes 2 on the first edge side 12 and the second group pe 10 of internal electrodes 2 'on the second edge side 14 free.

On the first edge side 12, the second group 10 of inner electrodes 2 'is covered by the electrically insulating layer 15 and consequently electrically insulated by the electrically insulating layer 15 from the collecting contact 11 arranged thereon. On the second edge side 14, the first group 9 of internal electrodes 2 is covered by the electrically insulating layer 15 and consequently electrically insulated by the electrically insulating layer 15 from the collecting contact 13 arranged thereon.

The contact structure 8 of the collecting contacts 11 according to a first embodiment is shown in the detailed view of Figure 2. FIG. 2 shows the contact structure 8 of the first collecting contact 11. The contact structure 8 of the second collective contact 13 is the same.

In the detailed view of Figure 2, a part of the first edge side 12 of the multilayer piezoelectric actuator 1 with four of the piezoelectrically active layers 3 and three Innenelektrodenla- gene 2 is shown. The electrically insulating layer 15 is arranged on the surface 6 of the body 7 of the multilayer piezoelectric actuator 1 and exposes every second internal electrode 2. The interposed inner electrode 2 'of the second group 10 is covered by the electrically insulating layer 15 and electrically insulated with this electrically insulating layer 15 of the first collecting contact 11 arranged thereon.

The contact structure 8 consists of two layers 18, 19. A first lower electrically conductive layer 18 has nanoscale grains, not shown, and is in the openings. gene 16 of the electrically insulating layer 15 is arranged. The first electrically conductive layer 18 is in direct contact and in electrical connection with the exposed inner electrode 2, which is disposed within the through opening 16.

In this embodiment, the first layer 18 is completely disposed within the respective openings 16. The thickness of the first layer 18 is smaller than the thickness of the electrically insulating layer 15. The first layer 18 consists of a multiplicity of regions 20, which are separated from one another by the electrically insulating layer 15. The nanoscale grains of the first electrically conductive layer 18 consist of an electrically conductive metal or an electrically conductive alloy, such as silver or gold and their alloys.

The second electrically conductive layer 19 of the contact structure 8 extends over the entire edge side 12 of the multilayer piezoactuator 1 and into the through openings 16 of the electrically insulating layer 15. The second layer 19 is directly on the surface 21 of the electrically insulating layer 15 and on the first electrically conductive layer 18 is arranged. The second electrically conductive layer 19 provides the collecting contact 11, since it electrically connects the inner electrodes 2 of the first group 9 to each other. The second layer 19 is made of a conductive adhesive. In a further embodiment, the second layer is applied by a galvanic process.

The nanoscale grains of the first layer lead to a higher contact area between the contact structure 8 and the inner electrode 2. This higher contact surface provides a lower contact resistance and an improved mechanical Resilience of the connection between the contact structure 8 and the internal electrodes 2 before.

The inner electrode layers 2 have a thickness of typically 2 to 3 .mu.m and the nanoscale grains of the first

Layer 18 has an average diameter of 2 to 100 nm. Consequently, several nanoscale grains are in direct contact with the exposed surface 17 of the inner electrode 2. The contact area between the first layer 18 and the inner electrode 2 is higher than the contact area achieved by using a layer with larger diameter particles, such as conductive adhesive Grains or particles with a larger diameter of 1 to 10 microns, can be provided.

The first electrically conductive layer 18 is disposed between the inner electrodes 2 and the second electrically conductive collecting layer 19 and serves at least in part as a bonding agent to improve the mechanical strength of the connection between the collecting contact 19 and the body 7 of the piezoelectric actuator 1 to improve. The adhesion-promoting effect can be further increased if, at least at the boundary between the inner electrode 2 and the first layer 18, phases are formed which are the products of a reaction or alloying of the material of the first layer 18 and the material of the inner electrodes 2. The material of the first layer 18 and the material of the inner electrode 2 may be selected and the manufacturing process adjusted so that a suitable reaction takes place.

Furthermore, the material of the first layer 18 may react with the material of the second layer 19, so that an improved Secured mechanical connection between these layers 18, 19 of the contact structure 8 is formed.

FIG. 3 shows a detailed view of a contact structure 8 'of a piezoelectric actuator 1' according to a second exemplary embodiment. The contact structure 8 'has a lower first electrically conductive layer 18' of nanoscale grains, not shown, and an upper second electrically conductive layer 19, as in the first exemplary embodiment, which is shown in FIG.

The contact structure 8 'of the second embodiment differs from the contact structure 8 of the first embodiment by the arrangement of the first lower electrically conductive layer 18'. In the second embodiment, the first layer 18 'is in the form of a closed layer that extends completely and approximately conformally across the electrically insulating layer 15. The first layer 18 'extends over the inner walls 22 and the bottom 23 of the openings 16, wherein an inner electrode 2 forms at least part of the bottom 23 of each second opening 16.

In this embodiment, the second upper electrically conductive layer 19 is only in direct contact with the first electrically conductive layer 18 'and not in direct contact with the electrically insulating layer 15. In the second embodiment, both the first layer connects 18' and the second layer 19, the exposed inner electrodes 2 of the first edge side 12 are electrically connected to one another.

The multilayer piezoelectric actuator 1 can be produced by the following method. First, a stacked component of alternately arranged inner electrode layers 2 and piecemeal zoelektrischaktiven layers 3 produced. Thereafter, the surfaces 6 of the component can be further processed, for example by grinding, to form a surface 6 of the ceramic piezoelectrically active layers 3 and the inner electrode layers 2.

An electrically insulating layer 15 is applied at least on the edge sides 12, 14 of the body 7, at which the collecting contacts 11, 13 are applied later. This electrically insulating layer 15 can be used as a closed

Layer or a structured layer can be applied. In an embodiment, all surfaces 6 of the body 7 are coated with the electrically insulating layer 15. In the case of a closed layer, the electrically insulating layer 15 is patterned after application in order to expose the internal electrodes 2. In particular, every second inner electrode 2 is exposed on a first edge side 12, and on the opposite edge side 14 every second inner electrode 2 'is uncovered, which is not exposed on the first edge side 12.

The first layer 18 is applied in the through openings 16 in the electrically insulating layer 15. The first layer 18 may be applied as a suspension of nanoparticles in a solvent. The solvent is removed, for example, by aund a first layer 18 of nanoscale grains formed from the nanoparticles.

In an embodiment for producing a contact structure 8, which is illustrated in FIG. 2, the nanoparticles are applied in the through openings 16, for example by a screen printing method, so that the first electrically conductive layer 18 is completely inside the through openings 16 is arranged. In this case, the patterned electrically insulating layer 15 may be used as a mask.

In one embodiment for producing a contact structure 8 ', which is illustrated in FIG. 3, the nanoparticles are applied as a closed layer 18', for example by dipping, which extends over the electrically insulating layer 15 and through openings 16.

In this embodiment, the applied closed layer 18 'on the two opposite edge sides 12, 14 of the body 7 is structured so that two portions of the first electrically conductive layer 18', which are electrically separated from each other, on the two opposite edge sides 12, 14 is formed. This can be done by the selective application of the first layer 18 'only on these two edge sides 12, 14 or by the application of a closed layer 18' on all edge sides 5 of the body 7, which is subsequently patterned.

For producing the contact structure 8, 8 ', which is shown in FIG. 2 or in FIG. 3, a second layer 19 of conductive adhesive is applied after the application and formation of the first layer 18, 18' of the contact structure 8, 8 '. The second layer 19 is applied at least on the edge sides 12, 14 on which the collecting contacts 11, 13 are to be arranged. The second layer 19 extends between the exposed internal electrodes 2, 2 'of one of the two groups 9, 10 and electrically connects the internal electrodes 2, 2' of these groups 9, 10 to one another.

As with the first layer 18, 18 ', the applied closed second layer 19 can be patterned on the two opposite edge sides 12, 14 of the body 7, so that two areas and consequently two collecting contacts 11, 13, which are electrically separated from each other, are formed. This can be done by the selective application of the second layer 19 or by the application of a closed layer 19, which is subsequently structured.

After the application of the second layer 19, it can be treated, for example by thermal treatment, to produce an electrically conductive layer and / or to increase the electrical conductivity of this second layer 19. Subsequently, an outer protective layer, not shown, can be applied to the multilayer piezoelectric actuator.

Claims

claims

1. contact structure (8, 8 ') of an electronic component (1) with a ceramic body (7) and at least one inner electrode (2), which is arranged in the ceramic body (7), extending up to a first surface (6 ) of the device

(1) and forms a region (17) of the first surface (6) of the component (1), wherein the first surface (6) has an electrically insulating layer (15) with at least one through opening (16) which comprises at least one part the inner electrode (2) exposes, wherein the contact structure (8,8 ')

a first electrically conductive layer (18, 18 ') of electrically conductive nanoscale grains arranged in the through opening (16) and with the inner electrode arranged therein

(2) are electrically connected, and

- A second electrically conductive contact layer (19) disposed on the first electrically conductive layer (18) and electrically connected to the inner electrode (2).

2. Contact structure (8; 8 ') according to claim 1, characterized in that the electrically conductive nanoscale grains of one or more of the elements Ag, Au, Cu, Ni, Cr, Pt, Pd, Ti and W.

3. Contact structure (8; 8 ') according to claim 1 or claim 2, characterized in that the first electrically conductive layer (18; 18') is formed from wet-chemically applied nanoscale particles.

4. contact structure (8; 8 ') according to one of claims 1 to 3, characterized in that the second electrically conductive layer (19) comprises metallic grains.

5. contact structure (8; 8 ') according to one of claims 1 to 4, characterized in that the boundary between the first electrically conductive layer (18; 18') and the inner electrode (2) has phases which the material of the inner electrode ( 2) and the material of the nanoscale grains.

6. Contact structure (8; 8 ') according to one of claims 1 to 5, characterized in that the second electrically conductive contact layer (19) has a conductive adhesive.

7. Contact structure (8; 8 ') according to one of claims 1 to 6, characterized in that the electrically insulating layer (15) has a plurality of strip-shaped through-openings (16) each having a strip-shaped surface (17) of an inner electrode (2 ) uncover.

8. contact structure (8) according to one of claims 1 to 7, characterized in that the first electrically conductive layer (18) is disposed completely within the through opening (16).

The contact structure according to claim 1, wherein the first electrically conductive layer is further arranged on the electrically insulating layer.

10. contact structure (8; 8 ') according to claim 9, characterized in that the first electrically conductive layer (18, 18 ') electrically interconnects a plurality of exposed internal electrodes (2) of the first surface (6).

11. Contact structure (8; 8 ') according to one of claims 1 to

10, characterized in that further comprises a protective layer on the second electrically conductive contact layer (19) is arranged.

12. contact structure (8; 8 ') according to claim 11, characterized in that the protective layer completely encloses the component (1) on the side surfaces.

13.Contact structure (8; 8 ') according to claim 11 or claim 12, characterized in that the protective layer is electrically insulating.

14. Contact structure (8; 8 ') according to one of claims 10 to 13, characterized in that the protective layer comprises plastic.

15. Contact structure (8; 8 ') according to one of claims 1 to

14, characterized in that the electrically insulating layer (15) is a further layer which is arranged on the ceramic body (7).

16. Contact structure according to one of claims 1 to 14, characterized in that the electrically insulating layer of the ceramic body

(7) of the component (1) is formed.

17. An electronic component (1) having a contact structure (8; 8 ') according to one of claims 1 to 16, wherein the electronic component (1) has a ceramic body (7) and at least one inner electrode (2), which in the ceramic body (7) is arranged, extends to a first surface (6) of the component (1) and forms a region (17) of the first surface (6) of the component (1), wherein the first surface (6) is an electrically insulating Layer (15) having at least one through opening (16) which exposes at least a portion of the inner electrode (2).

18, component (1) according to claim 17, characterized in that the electronic component (1) is a Vielschichtpiezoaktor having a plurality of piezoelectrically active layers (3) and a plurality of electrically conductive Innenelektrodenla- conditions (2), wherein the electrically conductive Innenelekt- rodenlagen (2) each provide an electrically conductive inner electrode, and wherein the piezoelectrically active layers (3) and the electrically conductive inner electrode layers (2) are alternately stacked on each other in a stacking direction (4).

19.Bauelement (1) according to claim 18, characterized in that the first surface (6) in the stacking direction (4) and each second inner electrode layer (2) of the first surface (6) in a through opening (16) of the electrically insulating Layer (15) is arranged.

20. The component (1) according to claim 18 or claim 19, characterized in that the second electrically conductive contact layer (19) electrically connects each second of the plurality of internal electrode layers (2) of the first surface (6).

21, component (1) according to one he claims 18 to 20, characterized in that the piezoelectrically active layers (3) are almost fully active.

22, component (1) according to one of claims 18 to 20, characterized in that the piezoelectrically active layers (3) do not have piezoelectrically active areas.

23. The component (1) according to any one of claims 17 to 22, characterized in that the component (1) has a second surface (6 '), which is arranged opposite the first surface (6) and a contact structure (8; ) according to one of the claims 1 to 26.

24. The component (1) according to claim 23, characterized in that the second surface has a multiplicity of the alternating piezoelectric layers (3) and electrically conductive inner electrode layers (2) and an electrically insulating layer (15) with openings (16), wherein a through opening (16) exposes each second inner electrode layer (2 ') of the second surface (6') that is not electrically connected to the second electrically conductive contact layer (19) on the first surface (6).

25. A method for contacting a ceramic component (1), comprising the following steps:

- Providing a device (1) having a ceramic body (7) and at least one inner electrode (2), which is arranged in the ceramic body (7), extending to a first surface (6) of the device (1) and a Area (17) of the first surface (6) of the device (1), wherein the first surface (6) has an electrically insulating layer (15) with at least one through opening (16) exposing at least a portion of the inner electrode (2) .

- Applying a first layer (18, 18 ') with electrically conductive nanoparticles in the through opening (16),

Depositing a second electrically conductive layer (19) on the first layer (18; 18 '), the inner electrode (2) being electrically connected to the second layer (19) over the first layer (18; 18').

26. The method according to claim 25, characterized in that the component (1) has a plurality of piezoelectrically active layers (3) and a plurality of electrically conductive inner electrode layers (2) which are alternately stacked on each other in a stacking direction (4) ,

27. The method according to claim 26, characterized in that the electrically insulating layer (15) is structured so that a through opening (16) exposes every second inner electrode layer (2) of the first upper side (6).

28. The method according to claim 26 or 27, characterized in that the component (1) has a second surface (6 ') which is arranged opposite to the first surface (6), and that the second surface (6') a plurality of alternating piezoelectric layers (3) and electrically conductive inner electrode layers (2), wherein an electrically insulating layer (15) with through openings (16) on the second surface (6 ') is structured such that a through opening (16) exposes each second internal electrode layer (2 ') of the second surface (6') that is not electrically connected to the second electrically conductive contact layer (11) on the first surface (6).

29. The method according to claim 28, characterized in that a first layer (18, 18 ') with electrically conductive nanoparticles in the through openings (16) of the second surface (6') is applied.

30. The method according to any one of claims 25 to 29, characterized in that the inner electrode (2) of the first surface (6) over the second contact layer (19) on the first surface

(6) is arranged to be electrically connected to each other.

A method according to claim 25 or claim 30, characterized in that the inner electrode (2 ') of the second surface (6') is electrically connected to each other via the second contact layer (19) disposed on the second surface (6 ') become,

32. The method according to any one of claims 25 to 31, characterized in that the nanoparticles are applied in a mixture with a solvent or in a mixture with an organic binder.

33. The method according to any one of claims 25 to 32, characterized in that the nanoparticles are applied by a screen printing method, spraying or dipping.

34. The method according to any one of claims 25 to 33, characterized in that when applying the nanoparticles in the through-opening (16), the electrically insulating layer (15) is used as a mask.

35. The method according to any one of claims 25 to 34, characterized in that an electrical connection between the first layer (18; 18 ') and the inner electrode (2) takes place by a thermal treatment.

36. The method according to any one of claims 25 to 35, characterized in that an electrical connection between the first layer (18; 18 ') and in the through opening (16) exposed inner electrode (2) by a chemical reaction between the first layer (18 18, 18 ') and the inner electrode (2) is generated.

37. Method according to claim 25, characterized in that a first electrically conductive layer (18, 18 ') with nanoscale grains is formed from the applied nanoparticles.

38. The method according to any one of claims 25 to 37, characterized in that the electrically insulating layer (15) by spraying or dipping or by a screen printing or laminating a film is applied.

39. The method according to claim 38, characterized in that after the application of the electrically insulating layer (15), the electrically insulating layer (15) is patterned with laser ablation or a photolithographic method.

40. The method according to any one of claims 25 to 39, characterized in that the second electrically conductive layer (19) by spraying or dipping or by a screen printing method is applied.