EP2394275B1 - Electrical multilayered component - Google Patents

Description

From the publication DE 10 2004 058 410 A1 is an electrical multilayer component with ESD protection element known. In DE 10 2004 010001 A1 For example, an electrical component is described which has a stack of ceramic layers which form a base body and electrode layers arranged therebetween, which form a capacitor. A phase shifter is applied to a ceramic layer. The electrode layers are electrically conductively connected by means of through-contacts running in the interior of the main body with contact surfaces.

The invention is defined by the features of claim 1.

The object of the present invention is to specify a multilayer electrical component comprising an ESD protection device with a low breakdown voltage and a low ESD clamping voltage.

This object is achieved by an electrical multilayer component according to claim 1. Advantageous embodiments of the electrical multilayer component are the subject of the dependent claims.

It is specified an electrical multilayer component having a base body with at least two outer electrodes. The electrical multilayer component has at least one first and at least one second inner electrode, which are electrically conductively connected to one outer electrode each are. The inner electrode is connected directly or via plated-through holes in the multilayer component with the outer electrode.

The electrical multilayer component has at least one ceramic varistor layer. The ceramic varistor layer comprises at least the first inner electrode. The first inner electrode is preferably largely surrounded by the ceramic varistor layer, wherein the first inner electrode is freely contactable at least in the region of the contact to the outer electrode. In another Embodiment, the first inner electrode is applied directly to the varistor layer.

The multilayer electrical component comprises at least one dielectric layer. The dielectric layer is arranged at least between a varistor layer and at least one further layer.

Preferably, the further layer comprises the second inner electrode. In one embodiment, the second inner electrode is largely enclosed by the further layer, wherein the second inner electrode is freely contactable at least in the region of the contact with its outer electrode. In a further embodiment, the second inner electrode is preferably applied directly to the further layer.

The dielectric layer has at least one opening. The opening may be formed as a breakthrough, as a recess or as a cavity. The opening in the dielectric layer is filled with a semiconducting material or a metal. Preferably, the opening is completely filled. In a further embodiment, however, single or multiple closed or open cavities are present in the filling of the opening.

In an embodiment, the semiconductive material with which one or more openings in the dielectric layer are filled comprises a varistor ceramic. The varistor ceramic, with which the opening in the dielectric layer is filled, is preferably identical to the varistor ceramic of the further varistor layer.

In a further embodiment, the varistor ceramic in the opening of the dielectric layer is different from the ceramic of the varistor layer.

In a further embodiment, the semiconducting material comprises a resistance material.

In an embodiment, the metal with which one or more openings of a dielectric layer are filled comprises a metal, which preferably comprises silver, palladium, platinum, silver palladium or other suitable metals.

In one embodiment, openings in the dielectric layer may be filled with different materials. Preferably, all openings of a dielectric layer are filled with the same material.

In one embodiment, the main body of the electrical multilayer component comprises cover packages, which terminate the basic body of the multilayer component in the thickness direction upwards and downwards. The cover packages each comprise at least one dielectric layer.

In an embodiment, the cover packages of the multilayer electrical component and the dielectric layers having at least one opening may comprise the same material. In a further embodiment, it is also possible for the cover packages and the dielectric layer to comprise different materials.

Preferably, for the dielectric layer zirconia (ZrO ₂ ) or a zirconia-glass composite, an alumina (AlO _x ) or a Alumina-glass composite, a manganese oxide (MnO) or a manganese oxide glass used. However, the dielectric layers may also comprise other suitable materials.

In one embodiment, the electrical multilayer component has one or more plated-through holes, so-called vias, with which individual or all internal electrodes of the electrical multilayer component are connected to the external contacts.

In one embodiment, the external contacts of the electrical multilayer component are formed as an array (row or matrix arrangement). In particular Land Grid Array (LGA) or Ball Grid Array (BGA) are suitable.

When contacting the multilayer electrical component via arrays (LGA, BGA), the internal electrodes of the electrical multilayer component are preferably connected to the external contacts via plated-through holes.

In one embodiment of the multilayer electrical component, the dielectric layer, which comprises at least one opening, is designed such that it forms an ESD discharge gap together with at least two adjacent varistor layers and two overlapping internal electrodes.

In a further embodiment, the opening in the dielectric layer is filled with a semiconducting material or a metal, in particular by a method of printing on the dielectric layer, in such a way that a so-called catch pad known per se is formed.

A via (via) can be arranged thereon, whereby a free-standing electrode structure is formed over the dielectric layer.

In a preferred embodiment, the electrical multilayer component has the function of a varistor with integrated ESD protection component.

The varistor preferably has a capacity of less than 1 pF.

The ESD protection component of the multilayer electrical component is preferably designed such that it has an ESD breakdown voltage of less than 20 V at 1 mA current.

For an ESD pulse with a voltage of 8 kV, which is applied to the multilayer electrical component, the ESD protection component of the electrical multilayer component preferably has an ESD clamping voltage of less than 500 V.

An electrical multilayer component as described above has a reduction in the total capacitance of the component, especially as a result of the arrangement of the small capacitance of the dielectric layer connected in series with the varistor capacitance. The clamping voltage of the electrical multilayer component is only slightly increased by the dielectric layer compared to conventional multilayer components.

The specified clamping voltage of the ESD protection component is essentially dependent on the distance between the inner electrode layers.

By a design of the electric multilayer component as described above, a low clamping voltage is thus achieved with a very small capacitance.

Due to the additional dielectric layer between the varistor layer, the total capacitance of the electrical multilayer component is significantly reduced, as a result of which the current-carrying capacity and pulse stability of the component are further increased.

The objects described above will be explained in more detail with reference to the following figures and embodiments. The drawings described below are not to be considered as true to scale. Rather, the representations can be enlarged, reduced or distorted in detail. Elements that are equal to each other or that perform the same function are denoted by the same reference numerals.

Figur 1

einen schematischen Aufbau eines ersten Ausführungsbeispiels des elektrischen Vielschichtbauelements,

Figur 2

eine weitere Ausführungsform des elektrischen Vielschichtbauelements,

Figur 3

eine weitere Ausführungsform des elektrischen Vielschichtbauelements, wobei die Außenkontakte als Ball-Grid-Array ausgeführt sind,

Figur 4

eine weitere Ausführungsform des elektrischen Vielschichtbauelements, wobei die Außenkontakte als Land-Grid-Arrays ausgeführt sind,

Figur 5

eine weitere Ausführungsform des elektrischen Vielschichtbauelements, wobei die dielektrische Schicht zwei Öffnungen aufweist,

Figur 6

eine weitere Ausführungsform des elektrischen Vielschichtbauelements, das mehrere parallel geschaltete ESD-Bereiche in einem Vielschichtbauelement zeigt,

Figur 7

eine weitere Ausführungsform des elektrischen Vielschichtbauelements, bei dem zwischen zwei Elektroden mehrere dielektrische Schichten mit Durchbrüchen angeordnet sind.

Figur 8

eine weitere Ausführungsform des elektrischen Vielschichtbauelements, bei der auf der von der Varistorschicht abgewandten Seite der dielektrischen Schicht ein Catch-Pad auf der Füllung der Öffnung vorhanden ist.

Figur 9

eine weitere Ausführungsform des elektrischen Vielschichtbauelements, bei der auf der der Varistorschicht zugewandten Seite der dielektrischen Schicht ein Catch-Pad auf der Füllung der Öffnung vorhanden ist.

Show it:

FIG. 1

a schematic structure of a first embodiment of the electrical multilayer component,

FIG. 2

a further embodiment of the electrical multilayer component,

FIG. 3

a further embodiment of the electrical multilayer component, wherein the external contacts are designed as a ball-grid array,

FIG. 4

a further embodiment of the electrical multilayer component, wherein the external contacts are designed as land grid arrays,

FIG. 5

a further embodiment of the multilayer electrical component, wherein the dielectric layer has two openings,

FIG. 6

a further embodiment of the multilayer electrical component, which shows a plurality of parallel connected ESD regions in a multilayer component,

FIG. 7

a further embodiment of the electrical multilayer component, in which a plurality of dielectric layers are arranged with openings between two electrodes.

FIG. 8

a further embodiment of the electrical multilayer component, in which on the side facing away from the varistor layer of the dielectric layer, a catch pad on the filling of the opening is present.

FIG. 9

a further embodiment of the electrical multilayer component, wherein on the varistor layer side facing the dielectric layer, a catch pad on the filling of the opening is present.

In FIG. 1 a first embodiment of a multilayer electrical component is shown, which comprises a base body 1. On the side surfaces of the base body 1 are Outer electrodes 2, 2 'are arranged, which are conductively connected to the inside of the main body 1 lying inside electrodes 3, 4. The main body 1 has a varistor layer 5, which comprises a first inner electrode 3. The first inner electrode 3 is largely enclosed by the varistor layer 5. The electrical multilayer component has a further layer 7, which in the illustrated embodiment is designed as a further varistor layer. The further layer 7 comprises a second inner electrode 4, which is largely enclosed by the further layer 7.

Between the varistor layer 5 and the further layer 7, a dielectric layer 6 is arranged, which has an opening 8. The opening 8 is filled with a semiconductive material or a metal. The main body 1 of the electrical multilayer component is terminated in the thickness direction by cover packages 9, 9 ', the cover packages 9, 9' preferably each comprising at least one dielectric layer.

FIG. 2 shows a further embodiment of the electrical multilayer component. The structure of the electric multilayer component is almost identical to the structure in FIG FIG. 1 wherein the first inner electrode 3 is applied on a surface of the varistor layer 5 and the second inner electrode 4 is applied on a surface of the further layer 7. The first inner electrode is arranged between the varistor layer 5 and the cover package 9. The second inner electrode 4 is arranged between the further layer 7 and the further second cover package 9 '.

FIG. 3 shows a further embodiment of the electrical multilayer component. The electrical multilayer component has a main body 1 in which a varistor layer 5 is arranged, on which a first inner electrode 3 is arranged. In the thickness direction, the first inner electrode 3 and the varistor layer 5 are closed by a first cover package 9 upwards. Below the varistor layer 5, a dielectric layer 6 is arranged, which has openings 8. The openings 8 are filled with a semiconducting material or metal. On the underside of the dielectric layer 6, second internal electrodes 4 are arranged. The first inner electrode 3 and the second inner electrodes 4 are connected via vias 10 with external contacts 2. The vias 10 can, for example, as in the FIG. 3 be shown cylindrical or frustoconical, wherein the vias 10, for example, in the direction of the external contacts 2 or in the direction of the internal electrodes 3, 4 can taper towards. The external contacts are designed as ball-grid arrays in the illustrated embodiment. The main body 1 of the electrical multilayer component is closed in the thickness direction down by a second cover package 9 '.

In FIG. 4 a further embodiment of the electrical multilayer component is shown, which corresponds to the embodiment in FIG. 3 is similar, wherein the dielectric layer 6 has the two openings 8. The dielectric layer 6 is arranged in the thickness direction between two layers 5, 7. In the illustrated embodiment, the two layers 5, 7 are designed as varistor ceramic. The external contacts 2, 2 'of the electrical multilayer component are designed as land grid arrays in the illustrated embodiment. The vias can, for example, as in the FIG. 4 be shown cylindrical or frusto-conical, the vias can, for example, in the direction of the external contacts 2, 2 'or taper towards the internal electrodes 3, 4 out.

FIG. 5 shows a further embodiment of the multilayer electrical component, the embodiment of FIG. 1 similar. The dielectric layer 6 in the FIG. 5 has two openings 8, which are filled with a semiconducting material or with a metal.

FIG. 6 shows a further embodiment of the electrical multilayer component, wherein the electrical multilayer component comprises three parallel ESD protection elements. The ESD protection elements are each in the FIG. 2 already described in detail. Each of the ESD protection elements comprises a first varistor layer 5 and a further layer 7. The further layer 7 is designed as a further varistor layer in the illustrated embodiment. Between the varistor layer 5 and the further layer 7, a dielectric layer 6 is arranged, which has an opening 8. The opening 8 is filled with a semiconductive material or with metal. The ESD protection elements each have a first inner electrode 3 and a second inner electrode 4, wherein the inner electrodes 3, 4 are applied to the varistor layer 5 or to the further layer 7.

FIG. 7 shows a further embodiment of the electrical multilayer component. The electrical multilayer component has a base body 1 with cover packages 9, 9 ', the cover packages 9, 9' preferably comprising at least one dielectric layer. Between the cover packages 9, 9 ', a varistor layer 5 and a further layer 7 are arranged, wherein the further layer 7 is designed as a varistor layer. Between the varistor layer 5 and the further layer 7, three dielectric intermediate layers 6 are arranged, which are separated from one another by intermediate layers of a varistor ceramic are spaced in the thickness direction. The dielectric layers 6 each have an opening 8. The openings 8 of the dielectric layers 6 are each filled with a semiconductive material or the opening 8 'with a metal. The electrical multilayer component has internal electrodes 3, 4 which are connected to external contacts 2, 2 '. The first inner electrode 3 is arranged between the varistor layer 5 and the cover package 9. The second inner electrode 4 is arranged between the further layer 7 and the second cover package 9 '.

FIG. 8 shows an embodiment in which similar to the embodiments of the FIGS. 3 and 4 a base body 1, a varistor layer 5, a first inner electrode 3, a first cover package 9, a dielectric layer 6 with openings 8, a second cover package 9 ', vias 10 and external contacts 2, 2' are present. The openings 8 are filled with a semiconducting material or metal, so that catch pads 11 are formed, which spread on a surface of the dielectric layer 6 laterally to the openings 8. The catch pads 11 are in the embodiment of the FIG. 8 on the side facing away from the varistor layer 5 side of the dielectric layer 6. The catch pads 11 may be prepared, for example, that the openings are filled by a method of printing with the semiconducting material or metal, so that a proportion of the fillings material used forms the top-side catch pads 11. The catch pads 11 can be like in the FIG. 8 shown provided with the associated vias 10 and so are electrically connected to the external contacts 2 '. The catch pads 11 may act as second internal electrodes. It may additionally second Internal electrodes are provided in electrically conductive connection with the catch pads 11.

In the embodiment of the FIG. 8 For example, typical dimensions are a thickness of the dielectric layer 6 of 10 μm to 30 μm, a diameter of the openings 8 of 20 μm to 30 μm, a diameter of the catch pads 11 of about 100 μm, a thickness of the catch pads of FIG μm to 5 μm and a height of a vias 10 plus catch pad 11 of about 50 μm. For example, the vias 10 may be cylindrical or conical.

FIG. 9 shows a further embodiment, in which similar to the embodiment according to FIG. 8 a base body 1, a varistor layer 5, a first inner electrode 3, a first cover package 9, a dielectric layer 6 with openings 8, a second cover package 9 ', vias 10 and external contacts 2, 2' are present. The openings 8 are filled with a semiconducting material or metal, so that catch pads 11 are formed, which spread on a surface of the dielectric layer 6 laterally to the openings 8. The catch pads 11 are in the embodiment of the FIG. 9 Second inner electrodes 4 are arranged on the side facing away from the varistor layer 5 side of the dielectric layer 6 and electrically connected via vias 10 with external contacts 2 '. The dimensions, in particular the openings 8 and the catch pads 11, the above to the embodiment of the FIG. 8 corresponding dimensions.

In further embodiments, the electrical multilayer component comprises a plurality of ESD protection devices connected in series or in parallel, which are protected by at least a dielectric layer having one or more openings and at least one adjacent varistor layer are formed.

It is within the scope of the invention to combine features of the described embodiments with each other in order to obtain further embodiments.

LIST OF REFERENCE NUMBERS

1

body

2, 2 '

outer electrode

3

first inner electrode

4

second inner electrode

5

varistor

6

dielectric layer

7

another layer

8, 8 '

opening

9, 9 '

deck package

10

vias

11

Catch pad

Claims (15)

1. Multilayer electrical component having

   - a main body (1) with external electrodes (2, 2'),

   - internal electrodes (3, 4) that are each connected to an external electrode (2, 2') in an electrically conductive manner,

   - a ceramic varistor layer (5) that is provided with one of the internal electrodes (3), and

   - a dielectric layer (6) adjoining the varistor layer (5),

   - wherein the internal electrodes (3, 4) are arranged on mutually opposite sides of the dielectric layer (6), and

   - wherein the dielectric layer (6) has, between the internal electrodes (3, 4), at least one opening that is filled with a semiconducting material or a metal, such that the semiconducting material present in the opening (8) or the metal present in the opening (8) adjoins the varistor layer (5) in a planar manner.
2. Multilayer electrical component according to Claim 1, in which
   the opening (8) is filled with semiconducting material that comprises a varistor ceramic or a resistor material.
3. Multilayer electrical component according to Claim 1, in which
   the opening (8) is filled with metal, which comprises Ag, Pd, Pt or AgPd.
4. Multilayer electrical component according to one of Claims 1 to 3, in which
   a further layer (7) is arranged on that side of the dielectric layer (6) that is remote from the varistor layer (5), said further layer (7) being in the form of a ceramic varistor layer and being provided with one of the internal electrodes (4).
5. Multilayer electrical component according to one of Claims 1 to 4, in which
   the dielectric layer (6) comprises ZrO₂, a ZrO₂-glass composite, AlO_x, an AlO_x glass, MgO or an MgO glass.
6. Multilayer electrical component according to one of Claims 1 to 5, in which
   the main body (1) has covering assemblies (9, 9') that each comprise at least one further dielectric layer.
7. Multilayer electrical component according to one of Claims 1 to 6, in which
   the internal electrodes (3, 4) are connected to the external contacts (2, 2') via vias (10).
8. Multilayer electrical component according to one of Claims 1 to 7, in which
   the external contacts (2, 2') are in the form of a land grid array (LGA) or ball grid array (BGA).
9. Multilayer electrical component according to one of Claims 1 to 8, in which
   the dielectric layer (6) is configured such that, together with at least two adjacent varistor layers (5) that are present as a whole and the internal electrodes configured as two overlapping internal electrodes (2, 3), it forms an ESD discharge section.
10. Multilayer electrical component according to one of Claims 1 to 9, which has the function of a varistor with an integrated ESD protective component.
11. Multilayer electrical component according to one of Claims 1 to 10, which has a capacitance of less than 1 pF.
12. Multilayer electrical component according to one of Claims 1 to 11, which has, at a current of 1 mA, an ESD breakdown voltage of less than 20 V.
13. Multilayer electrical component according to one of Claims 1 to 12, which, in the case of an ESD pulse with a voltage of 8 kV, has an ESD clamping voltage of less than 500 V.
14. Multilayer electrical component according to one of Claims 1 to 13, in which
    the opening 8) in the dielectric layer (6) is filled with a semiconducting material or a metal such that a pad (11) is formed that spreads over a surface of the dielectric layer (6) laterally to the opening (8) .
15. Multilayer electrical component according to Claim 14, in which the pad (11) is provided with a via (10) .

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