Electric component with a protected current feeding terminal

• US 7,504,925 B2
• Filed: 05/25/2006
• Issued: 03/17/2009
• Est. Priority Date: 05/27/2005
• Status: Active Grant

• 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): Gandhi; Jayprakash N
• Assistant Examiner(s): Thomas; Bradley H.
• Application Number:
  US11/420,286
• Publication Number:
  US 20060267722A1
• Time in Patent Office: 1,027 Days
• Field of Search: 337/401, 337/300, 337/327, 337/380, 337/393, 337/394, 337/398, 337403-405, 337414-416, 337/159, 337/143, 257/665, 298/78, 297/56
• US Class Current: 337/159
• CPC Class Codes: H01G 2/16 with fusing elements
• CPC Class Codes: H01G 4/228 Terminals
• CPC Class Codes: H01H 2037/768 characterised by the composition of the fusible material
• CPC Class Codes: H01H 37/761 with a fusible element forming part of the switched circuit H01H37/767 takes precedence
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 23/5256 comprising fuses, i.e. connections having their state changed from conductive to non-conductive
• CPC Class Codes: H01L 23/5382 Adaptable interconnections, e.g. for engineering changes
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• 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 2201/0305 Solder used for other purposes than connections between PCB or components, e.g. for filling vias or for programmable patterns
• CPC Class Codes: H05K 2201/09072 Hole or recess under component or special relationship between hole and component
• CPC Class Codes: H05K 2201/10181 Fuse
• 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
• CPC Class Codes: H05K 2203/304 : Protecting a component during manufacturing
• CPC Class Codes: H05K 3/3421 : Leaded components
• CPC Class Codes: Y10T 29/49211 : of fused material
• CPC Class Codes: Y10T 29/53248 : Switch or fuse

Abstract

An electric device generates a predetermined amount of heat in the event of a malfunction. The electric device is protected from overheating in that it is arranged, with a fuse in a circuit, such that the fuse and the electric device are thermally coupled to one another, so that 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. An electric component comprising:

a package;

a chip arranged in the package; and

a lead frame conductively connected to the chip, the lead frame comprising a first terminal forming a current supply terminal of the chip, the first terminal passing partly within the package and partly outside the package, a part of the first terminal outside the package being a terminal pin of the package, the terminal pin consisting of a fusible material melting at a predetermined melting temperature, the terminal pin being configured such that the fusible material is removed from the first terminal in a molten state, so that the first terminal is interrupted outside the package, and at least a second and a third terminal, wherein said second or third terminals comprises a material having a melting temperature which is higher than that of the fusible material, wherein the predetermined melting temperature of the fusible material ranges between 200°

C. and 500°

C.

2. An electric component according to claim 1, wherein the terminal pin is made such that when the package is mechanically connected to a circuit carrier via the terminal pin, a deformation of the circuit carrier is partially compensated for by the terminal pin.

3. An electric component according to claim 1, wherein a cross-section of the fusible material is dimensioned such that a dissipation generated by the fusible material—

if a current within a nominal current range specified for the electrical component flows through same—

leads to a temperature of the fusible material which is lower than the predetermined melting temperature.

4. An electric component according to claim 1, wherein the fusible material consists of a metallic alloy.

5. An electric component according to claim 1, wherein the fusible material is selected from the group of alloys 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.

6. A method for protecting a chip, comprising:

electrically coupling the chip with a lead frame comprising at least a first, a second and a third terminal, wherein the first terminal fully or partially consists of a fusible material melting at a predetermined melting temperature, and wherein the second and third terminals comprise a material having a melting temperature which is higher than the predetermined melting temperature of the fusible material;

arranging the chip in a package such that the first terminal passes partly within the package and partly outside the package, wherein a part of the first terminal outside of the package consists of the fusible material and forms a terminal pin of the package,

the terminal pin being configured such that the fusible material is removed from the first terminal in a molten state outside of the package, so that the first terminal is interrupted, wherein the predetermined melting temperature of the fusible material ranges between 200°

C. and 500°

C.; and

supplying a current through said first terminal to the chip.

7. A method according to claim 6, wherein the terminal pin is made such that when the package is mechanically connected to a circuit carrier via the terminal pin, a deformation of the circuit carrier is partially compensated for by the terminal pin.

8. A method according to claim 6, wherein a cross-section of the fusible material is dimensioned such that dissipation loss generated by the fusible material—

if a current within a nominal current range specified for the device flows through same—

leads to a temperature of the fusible material which is lower than the predetermined melting temperature.

9. A method according to claim 6, wherein the fusible material consists of a metallic alloy.

10. A method according to claim 6, wherein the fusible material is selected from the group of alloys 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.