Method for producing a multi-layer varistor component and a multi-layer varistor component

Patent metadata

Field	Value
Publication number	US-9875831-B2
Application number	US-201414901694-A
Country	US
Kind code	B2
Filing date	May 20, 2014
Priority date	Jun 28, 2013
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

A method for producing a multi-layer varistor component is specified. A main body for the multi-layer varistor component includes a plurality of internal electrodes. The method further includes providing the main body with a starting material for a copper electrode layer in such a way that the starting material is directly connected to at least one internal electrode. A thermal treatment of the starting material is performed under a protective gas atmosphere in order to form the copper electrode layer.

First claim

The invention claimed is:

1. A method for producing a multi-layer varistor component, the method comprising:
providing a main body for the multi-layer varistor component, wherein the main body comprises a plurality of internal electrodes;
forming a starting material for a copper electrode layer on the main body in such a way that the starting material is directly connected to an internal electrode;
performing a thermal treatment of the starting material under a protective gas atmosphere in order to form the copper electrode layer; and
performing further steps to produce the completed multi-layer varistor component,
wherein the main body is exposed to the protective gas atmosphere during the thermal treatment, and
wherein the main body has a surface passivation that functions as a diffusion barrier for a diffusion of a protective gas of the protective gas atmosphere into the main body during the thermal treatment of the starting material.

2. The method according to claim 1 , wherein the surface passivation comprises a passivation layer that is interrupted in a region in which the copper electrode layer is directly electrically conductively connected to the internal electrodes.

3. The method according to claim 1 , wherein the starting material comprises a copper-containing paste that is decarbonized by the thermal treatment or fired into the main body.

4. The method according to claim 1 , wherein the thermal treatment is performed at temperatures below 570° C.

5. The method according to claim 1 , wherein the thermal treatment is performed at temperatures above 400° C.

6. The method according to claim 1 , wherein the thermal treatment is performed at temperatures above 400° C. and below 570° C.

7. The method according to claim 1 , wherein the protective gas atmosphere comprises nitrogen or a noble gas.

8. The method according to claim 1 , wherein the protective gas atmosphere has an oxygen proportion of less than 300 ppm.

9. The method according to claim 1 , wherein performing the further steps comprises depositing a further electrode layer on the copper electrode layer after the thermal treatment in order to form, together with the copper electrode layer, an external electrode of the multi-layer varistor component.

10. A multi-layer varistor component comprising:
a main body having a plurality of internal electrodes; and
an external electrode directly electrically conductively connected to the plurality of internal electrodes, the external electrode having a region with a copper electrode layer, the copper electrode layer having less than 0.1 atomic percent of oxygen; and
a surface passivation, which is interrupted in a region in which the copper electrode layer is directly electrically conductively connected to the internal electrodes.

11. The multi-layer varistor component according claim 10 , wherein the external electrode has a region that comprises a nickel layer.

12. The multi-layer varistor component according to claim 10 , wherein the external electrode has an external region.

13. The multi-layer varistor component according to claim 12 , wherein the external region comprises a tin layer.

14. A method for producing a multi-layer varistor component, the method comprising:
providing a main body for the multi-layer varistor component, wherein the main body comprises a plurality of internal electrodes;
providing the main body with a starting material for a copper electrode layer in such a way that the starting material is directly connected to an internal electrode;
performing a thermal treatment of the starting material under a protective gas atmosphere in order to form the copper electrode layer, wherein the copper electrode layer has less than 0.1 atomic percent of oxygen; and
performing further steps to produce the completed multi-layer varistor component,
wherein the main body is exposed to the protective gas atmosphere during the thermal treatment, and
wherein the main body has a surface passivation that functions as a diffusion barrier for a diffusion of a protective gas of the protective gas atmosphere into the main body during the thermal treatment of the starting material.

15. The method according to claim 14 , wherein the copper electrode layer of the completed multi-layer varistor component has less than 0.1 atomic percent of oxygen.

Assignees

• Epcos Ag

Inventors

• Dernovsek Oliver
• Koholka Jutta

Classifications

• H01C1/148

  the terminals embracing or surrounding the resistive element (H01C1/142 takes precedence) · CPC title

• H01C17/283

  Precursor compositions therefor, e.g. pastes, inks, glass frits · CPC title

• H01G4/2325

  characterised by the material of the terminals · CPC title

• H01C7/1006

  Thick film varistors · CPC title

• H01C17/281

  by thick film techniques · CPC title