Fuse element with trigger assistance

• US 7,554,432 B2
• Filed: 05/25/2006
• Issued: 06/30/2009
• Est. Priority Date: 05/27/2005
• Status: Expired due to Fees

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V., Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Maerz, Martin, Saliternig, Martin, Graf, Alfons
• Primary Examiner(s): Vortman; Anatoly
• Application Number:
  US11/420,280
• Publication Number:
  US 20060267721A1
• Time in Patent Office: 1,132 Days
• Field of Search: 337/159, 337/297, 337/290, 337/296, 337/416, 296/23, 361/104
• US Class Current: 337/296
• CPC Class Codes: H01C 7/126 Means for protecting against excessive pressure or for disconnecting in case of failure
• CPC Class Codes: H01G 2/16 with fusing elements
• CPC Class Codes: H01H 37/761 with a fusible element forming part of the switched circuit H01H37/767 takes precedence
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/01327 Intermediate phases, i.e. intermetallics compounds
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H05K 1/0201 Thermal arrangements, e.g. for cooling, heating or preventing overheating
• CPC Class Codes: H05K 1/0293 Individual printed conductors which are adapted for modification, e.g. fusable or breakable conductors, printed switches
• CPC Class Codes: H05K 2201/09036 Recesses or grooves in insulating substrate recess in metallic substrate H05K2201/09745
• CPC Class Codes: H05K 2201/09063 Holes or slots in insulating substrate not used for electrical connections
• CPC Class Codes: H05K 2201/10181 Fuse
• CPC Class Codes: H05K 2201/10909 Materials of terminal, e.g. of leads or electrodes of components
• CPC Class Codes: H05K 2201/2081 Compound repelling a metal, e.g. solder
• CPC Class Codes: H05K 2203/0415 Small preforms other than balls, e.g. discs, cylinders or pillars
• CPC Class Codes: H05K 2203/175 Configurations of connections suitable for easy deletion, e.g. modifiable circuits or temporary conductors for electroplating; Processes for deleting connections
• CPC Class Codes: H05K 2203/176 Removing, replacing or disconnecting component; Easily removable component thermal arrangements, e.g. to prevent overheating H05K1/0201
• CPC Class Codes: H05K 3/3489 : Composition of fluxes; Methods of application thereof; Other methods of activating the contact surfaces

Abstract

A fuse is provided in a circuit, such that the fuse and an electric device in the circuit are thermally coupled to one another. The generation of the amount of heat by the electric device causes a fusible material in the fuse to melt. In this manner, the current terminal path of the electric device is interrupted.

Claims

1. A discrete fuse element for protecting a current consumer, comprising:

a first terminal point;

a second terminal point;

a fusible material, which melts at a predetermined temperature, between the first and the second terminal points, which is configured to establish, in the non-molten state, an electrically conductive connection between the first and the second terminal points; and

an assisting means between the first and the second terminal points, configured to assist in removing the fusible material in the molten state from an area between the first and the second terminal points, wherein the fusible material is deposited on a surface of a carrier, and the assisting means includes a layer of solder stop resist which exhibits a property of repelling the fusible material.

2. A fuse element according to claim 1, wherein the assisting means is configured to exert a force, onto the molten fusible material, dimensioned such that the fusible material is not moved in the non-molten state, and is moved out of the area in the molten state.

3. A fuse element according to claim 1, wherein the assisting means comprises an assistance material which is in contact with the fusible material and reduces a viscosity of the fusible material once the fusible material has melted.

4. A fuse element according to claim 3, wherein the assisting means comprises a flux arranged on the fusible material of the fuse, the flux being embodied such that a flowing-off of the fusible material in the molten state is accelerated.

5. A fuse element according to claim 3, wherein the assisting means comprises one or more cores of a flux which are arranged within the fusible material of the fuse element, the flux being embodied such that a flowing-off of the fusible material in the molten state is accelerated.

6. A fuse element according to claim 5, wherein the carrier comprises several layers, and the surface of the carrier is formed of a layer repelling the fusible material.

7. A fuse element according to claim 1, wherein the first and the second terminals are mechanically connected to a carrier material located between the first and second terminals, the assisting means comprising a gap or a depression in the carrier material in the area of the fuse element, the fusible material covering the gap or the depression such that a free volume, which is not filled with the carrier material or the fusible material of the fuse, is formed in the carrier material in the area of the fuse.

8. A fuse element according to claim 7, wherein in the area of the fusible material, a depression in the carrier material is covered by the fusible material, so that a volume is limited by the carrier material and the fusible material, the volume being filled with a bulging material or an explosive.

9. A fuse element according to claim 7, which comprises an oblong carrier of the shape of a rectangular parallelepiped, on the first longitudinal side of which a first metallization is embodied as a first terminal point, and on the second longitudinal side of which a second metallization is embodied as a second terminal point, the assisting means being formed by the carrier, and the fusible material being arranged between the first and second metallizations on the carrier.

10. A fuse element according to claim 1, wherein the fusible material exhibits a melting temperature of between 200°

C. and 500°

C.

11. A fuse element according to claim 1, wherein the fusible material consists of a metallic alloy.

12. A fuse element according to claim 1, wherein the fusible material is an element selected from the group consisting of:

Alloy Melting point [°

C.] 82.6 Cd, 17.4 Zn 266, 80 Au, 20 Sn 280, 97.5 Pb, 2.5 Ag 303, 97.5 Pb, 1.5 Ag, 1 Sn 309, 92 Pb, 5 Sn, 2 Ag 296, 88 Au, 12 Ce 356, 96.4 Au, 3.6 Si  

 

 

370, and 95 Zn, 5 Al 382.

13. A method for protecting a current consumer, comprising:

providing a fuse element comprising a first terminal point,

a second terminal point, and a fusible material, which melts at a predetermined temperature, between the first and the second terminal points, which is configured to establish, in the non-molten state, an electrically conductive connection between the first and the second terminal points; and

providing an assisting means between the first and the second terminal points, configured to assist in removing the fusible material in the molten state from an area between the first and the second terminal points, wherein the fusible material is deposited on a surface of a carrier, and the assisting means includes a layer of solder stop resist which exhibits a property of repelling the fusible material.

14. A method according to claim 13, wherein the assisting means is configured to exert a force, onto the molten fusible material, dimensioned such that the fusible material is not moved in the non-molten state, and is moved out of the area in the molten state.

15. A method according to claim 13, wherein the assisting means comprises an assistance material which is in contact with the fusible material and reduces a viscosity of the fusible material once the fusible material has melted.

16. A method according to claim 13, wherein the first and the second terminals are mechanically connected to a carrier material located between the first and second terminals, the assisting means comprising a gap or a depression in the carrier material in the area of the fuse element, the fusible material covering the gap or the depression such that a free volume, which is not filled with the carrier material or the fusible material of the fuse, is formed in the carrier material in the area of the fuse.

17. A method according to claim 13, wherein the fusible material exhibits a melting temperature of between 200°

C. and 500°

C.

18. A method according to claim 13, wherein the fusible material consists of a metallic alloy.

19. A method according to claim 13, wherein the fusible material is an element selected from the group consisting of:

Alloy Melting point [°

C.] 82.6 Cd, 17.4 Zn 266, 80 Au, 20 Sn 280, 97.5 Pb, 2.5 Ag 303, 97.5 Pb, 1.5 Ag, 1 Sn 309, 92 Pb, 5 Sn, 2 Ag 296, 88 Au, 12 Ge 356, 96.4 Au, 3.6 Si  

 

 

370, and 95 Zn, 5 Al 382.

20. A discrete fuse element for protecting a current consumer, comprising:

a first terminal point;

a second terminal point;

a fusible material, which melts at a predetermined temperature, between the first and the second terminal points, which is configured to establish, in the non-molten state, an electrically conductive connection between the first and the second terminal points; and

an assisting means between the first and the second terminal points, configured to assist in removing the fusible material in the molten state from an area between the first and the second terminal points, wherein the fusible material is deposited on a surface of a carrier, and the assisting means includes a layer of solder stop resist which exhibits a property of repelling the fusible material, wherein the assisting means comprises an assistance material which is in contact with the fusible material and reduces a viscosity of the fusible material once the fusible material has melted, and wherein the assisting means comprises a flux arranged on the fusible material of the fuse, the flux being embodied such that a flowing-off of the fusible material in the molten state is accelerated.