LOW CURRENT FUSE

• US 20120092123A1
• Filed: 10/11/2011
• Published: 04/19/2012
• Est. Priority Date: 10/14/2010
• Status: Active Grant

• Current Assignee: Kyocera AVX Components Corporation (Kyocera Corporation)
• Original Assignee: AVX Corporation (Kyocera Corporation)
• Inventors: Daynov, Irina, Goldstein, Alona, Ovadia, Herzl, O'Neill, Elinor, Dakhyia, Michael
• Granted Patent: US 9,847,203 B2
• Time in Patent Office: Days
• US Class Current: 337/187
• CPC Class Codes: H01H 2085/0414 Surface mounted fuses
• CPC Class Codes: H01H 85/0411 Miniature fuses
• CPC Class Codes: H01H 85/06 characterised by the fusible material H01H85/11 takes precedence

Abstract

A multi layer fuse device includes a substrate and an elongated fuse element, having a pair of contact pads formed therewith at opposed longitudinal ends thereof formed on one surface of the substrate. A pair of passivation layers are provided covering the fuse and contact pads. Windows may be opened through both passivation layers above both of the contact pads, and conductive electrode material is electroplated through the windows to contact the contact pads and to extend partially above a top surface of the passivation layers. Exposed electroplated material may be coated with solderable conductive material or a surface mount termination may be provided. Electroplated material may cover a portion of the fuse surface prior to application of the passivation layers and extend to an end of the substrate so that windows are not required.

Claims

1. A surface mountable fuse rated at 0.025 to 0.125 amps.

2. The surface mountable fuse of claim 1 designed to blow if exposed to a maximum current in the range of about 0.06 and 0.5 amperes.

3. The surface mountable fuse of claim 1, comprising a fuse element consisting of a track of nickel or copper in the range of from 3 to 20 μ

m wide and from 0.2 to 2 μ

m thick.

4. The surface mountable fuse of claim 3 further comprising a dielectric substrate supporting the fuse element, the dielectric substrate comprising a material selected from the group comprising ceramic, glass and glass ceramic.

5. The surface mountable fuse of claim 3 wherein the dielectric substrate comprises glass.

6. The surface mountable fuse of claim 3 further comprising a thin layer of tantalum below the fuse metal.

7. The surface mountable fuse of claim 5 wherein the thin layer of tantalum has a thickness of several hundred angstroms.

8. The surface mountable fuse of claim 3 further comprising a passivation layer protecting the nickel or copper.

9. The surface mountable fuse of claim 8 wherein the passivation layer comprises silicon oxynitride.

10. The surface mountable fuse of claim 9 wherein the passivation layer is 1 to 6 microns thick.

11. The surface mountable fuse of claim 9 wherein an adhesive layer is deposited between the fuse metal and the passivation layer.

12. The surface mountable fuse of claim 9 wherein the adhesive layer comprises tantalum.

13. The surface mountable fuse of claim 9 further comprising an encapsulation layer of polyimide.

14. The surface mountable fuse of claim 1 configured for use in a land grid array (LGA) or in a surface mounted (SMD) application.

15. The surface mountable fuse of claim 3 further comprising terminations.

16. The surface mountable fuse of claim 16 wherein the terminations comprise contact pads at each end of the fuse element and accessible through window openings in the passivation layer.

17. The surface mountable fuse of claim 16 further comprising an encapsulation layer of a polyimide material with additional window openings generally corresponding to the window openings formed in passivation layer.

18. The surface mountable fuse of claim 16 further comprising a protective coating of benzocyclobutene (BCB) or epoxy.

19. The surface mountable fuse of claim 16 further comprising Copper (Cu) electrodes electroplated through the window openings above the contact pads such that the electrodes extend over passivation layer.

20. The surface mountable fuse of claim 16 wherein the exposed portion of the Cu electrodes 112 are terminated with nickel and tin (Ni/Sn) layers.

21. The surface mountable fuse of claim 16 wherein the exposed portion of the Cu electrodes are terminated using ball grid array (BGA) technology.

22. The surface mountable fuse of claim 16 fabricated as a component having overall dimensions of not more than 3 mm×

2 mm.

23. The surface mountable fuse of claim 16 fabricated as a component having overall dimensions of not more than 1 mm×

0.5 mm.

24. A fuse, comprising:

a substrate having respective top, bottom, side, and end surfaces;

an elongated fuse element formed on said top surface of said substrate;

a pair of contact pads integrally formed at opposed ends of said fuse element;

at least one passivation layer covering said fuse element and at least a portion of said contact pads;

first and second conductive electrodes coupled respectively to a top surface of each of said pair of contact pads; and

at least one conductive termination layer for each of said electrodes.