Composite electronic device, manufacturing method thereof, and connection structure of composite electronic device

1. A composite electronic device comprising an inductor element and an ESD protection element formed between two magnetic substrates, wherein

the inductor element includes insulation layers made of a resin, and conductor patterns formed on the insulation layers,

the ESD protection element includes a base insulation layer, a pair of electrodes arranged via gap formed therebetween on the base insulation layer, and an ESD absorbing layer arranged at least between the electrodes, and

the ESD absorbing layer includes a composite material having an insulation inorganic material and a conductive inorganic material discontinuously dispersed in a matrix of the insulation inorganic material.

2. The composite electronic device as claimed in claim 1 , wherein

the inductor element includes first and second spiral conductors formed on a plane surface perpendicular to a layer-laminating direction, and

the first and second spiral conductors constitute a common mode filter and are magnetically coupled with each other.

3. The composite electronic device as claimed in claim 1 , wherein an electrostatic capacitance of the ESD protection element has a value equal to or lower than 0.35 pF.

4. The composite electronic device as claimed in claim 1 , wherein

the resin is one of the polyimide resin and an epoxy resin, and

the insulation inorganic material is at least one kind selected from a group of Al 2 O 3 , TiO 2 , SiO 2 , ZnO, In 2 O 3 , NiO, CoO, SnO 2 , V 2 O 5 , CuO, MgO, ZrO 2 , AlN, BN, and SiC.

5. The composite electronic device as claimed in claim 1 , wherein the conductive inorganic material is at least one kind of metal or a metal compound of these metals selected from a group of C, Ni, Cu, Au, Ti, Cr, Ag, Pd, and Pt.

6. The composite electronic device as claimed in claim 1 , wherein the pair of electrodes is formed on a surface of one of the magnetic substrates via the base insulation layer.

7. The composite electronic device as claimed in claim 6 , wherein the inductor element includes first and second spiral conductors formed on a plane surface perpendicular to a layer-laminating direction,

the first and second spiral conductors constitute a common mode filter and are magnetically coupled with each other, and

the gap provided between the pair of electrodes are arranged not to be overlapped with conductor patterns of the inductor element viewed from the layer-laminating direction.

8. The composite electronic device as claimed in claim 1 , wherein the gap provided between the pair of electrodes are arranged not to be overlapped with conductor patterns of the inductor element viewed from the layer-laminating direction.

9. The composite electronic device as claimed in claim 8 , wherein the inductor element includes first and second spiral conductors formed on a plane surface perpendicular to a layer-laminating direction, the first and second spiral conductors constitute a common mode filter and are magnetically coupled with each other.

10. The composite electronic device as claimed in claim 8 , wherein the pair of electrodes are formed on a surface of one of the magnetic substrates via the base insulation layer.

11. A composite electronic device comprising a common-mode filter layer and an ESD protection layer provided between two magnetic substrates, wherein

the common-mode filter layer includes first and second insulation layers made of a resin, a first spiral conductor formed on the first insulation layer, and a second spiral conductor formed on the second insulation layer,

the ESD protection layer includes a first ESD protection element connected to one end of the first spiral conductor, and a second ESD protection element connected to one end of the second spiral conductor,

the first and second spiral conductors are formed in a plane-surface direction perpendicular to a layer-laminating direction, and are arranged to be magnetically coupled to each other,

each of the first and second ESD protection elements includes a pair of electrodes arranged via gap formed therebetween on a base insulation layer, and ESD absorbing layer arranged at least between the electrodes, and

the ESD absorbing layer includes a composite material having an insulation inorganic material and a conductive inorganic material discontinuously dispersed in a matrix of the insulation inorganic material.

12. The composite electronic device as claimed in claim 11 , further including

a third ESD protection element connected to the other end of the first spiral conductor, and

a fourth ESD protection element connected to the other end of the second spiral conductor, wherein

the third and fourth ESD protection elements have the same configurations as those of the first and second ESD protection elements.

13. The composite electronic device as claimed in claim 11 , wherein the pair of the electrodes is formed on one of the magnetic substrates via the base insulation layer.

14. The composite electronic device as claimed in claim 11 , wherein the gaps provided between the pair of electrodes are arranged not to be overlapped with the first and second spiral conductors of the common-mode filter layer viewed from the layer-laminating direction.

15. The composite electronic device as claimed in claim 12 , wherein the pair of electrodes is formed on one of the magnetic substrates via the base insulation layer.

16. A connection structure of a pair of signal lines and a composite electronic device, wherein

the composite electronic device includes an inductor element and an ESD protection element formed between two magnetic substrates,

the inductor element includes insulation layers made of a resin, and conductor patterns formed on the insulation layers,

the ESD protection element includes a base insulation layer, a pair of electrodes arranged via gap formed therebetween on the base insulation layer, and an ESD absorbing layer arranged at least between the electrodes,

the ESD absorbing layer includes a composite material having an insulation inorganic material and a conductive inorganic material discontinuously dispersed in a matrix of the insulation inorganic material,

the conductor patterns include first and second spiral conductors formed on a plane surface perpendicular to a layer-laminating direction,

the first and second spiral conductors constitute a common mode filter and are magnetically coupled with each other, and

one end of the first spiral conductor and one end of the second spiral conductor are connected to an input side of the pair of signal lines.

17. A connection structure of a pair of signal lines and a composite electronic device, wherein

the composite electronic device comprises a common-mode filter layer and an ESD protection layer provided between two magnetic substrates,

the common-mode filter layer includes first and second insulation layers made of a resin, a first spiral conductor formed on the first insulation layer, and a second spiral conductor formed on the second insulation layer,

the ESD protection layer includes a first ESD protection element connected to one end of the first spiral conductor, and a second ESD protection element connected to one end of the second spiral conductor,

the first and second spiral conductors are formed in a plane-surface direction perpendicular to a laminating direction, and are arranged to be magnetically coupled to each other,

each of the first and second ESD protection elements includes a pair of electrodes arranged via gap formed therebetween on a base insulation layer, and ESD absorbing layer arranged at least between the electrodes,

the ESD absorbing layer includes a composite material having an insulation inorganic material and a conductive inorganic material discontinuously dispersed in a matrix of the insulation inorganic material, and

the one end of the first spiral conductor and the one end of the second spiral conductor are connected to an input side of the pair of signal lines.

18. A method of manufacturing a composite electronic device, comprising:

forming an ESD protection layer on a surface of a first magnetic substrate;

forming a common-mode filter layer on a surface of the ESD protection layer; and

forming a second magnetic substrate on a surface of the common-mode filter layer, wherein

forming the ESD protection layer includes forming a base insulation layer on a surface of the first magnetic substrate, forming a pair of electrodes arranged via gap formed therebetween on a surface of the base insulation layer, and forming an ESD absorbing layer arranged at least between the electrodes, and

the ESD absorbing layer includes a composite material having an insulation inorganic material and a conductive inorganic material discontinuously dispersed in a matrix of the insulation inorganic material.

19. The method of manufacturing a composite electronic device as claimed in claim 18 , wherein

forming the common-mode filter layer includes alternately forming insulation layers made of a resin and conductor patterns, and

the insulation layers, the conductor patterns, the base insulation layer, and the electrodes are formed by a thin-film forming method.