Integrated circuit leadframes patterned for measuring the accurate amplitude of changing currents

• US 6,853,178 B2
• Filed: 06/02/2001
• Issued: 02/08/2005
• Est. Priority Date: 06/19/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Hayat-Dawoodi, Kambiz
• Primary Examiner(s): Zarneke, David
• Assistant Examiner(s): KOBERT, RUSSELL MARC
• Application Number:
  US09/873,057
• Publication Number:
  US 20010052780A1
• Time in Patent Office: 1,347 Days
• Field of Search: 257666-675, 257/677, 257/676, 174/52.4, 361/676, 361/783, 361/808, 361/813, 438/123, 324/207.2, 324/251, 324/117.H
• US Class Current: 324/117.00H
• CPC Class Codes: G01R 1/0433 Sockets for IC's or transistors
• CPC Class Codes: G01R 15/202 using Hall-effect devices Hall elements in arrangements for measuring electrical power G01R21/08
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45124 Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• 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 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/49503 characterised by the die pad
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• 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 2924/00014 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 2924/14 Integrated circuits
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/207 Diameter ranges

Abstract

A metallic leadframe for use with a semiconductor chip intended for operation in a changing magnetic field comprises a chip mount pad having at least one slit penetrating the whole thickness of the pad and substantially traversing the area of the pad from one edge to the opposite edge. This slit is wide enough to interrupt electron flow in the pad plane, but not wide enough to significantly reduce thermal conduction in a direction normal to the pad plane, whereby the slit is operable to disrupt eddy currents induced in the pad by the changing magnetic field.

A semiconductor device intended for operation in a changing magnetic field, comprising a leadframe with a chip mount pad having at least one slit in a configuration operable to suppress eddy currents induced in the pad by the changing magnetic field; an integrated circuit chip, having an active and a passive surface; the passive surface attached to the mount pad by a polymeric material; and the active surface having a Hall structure including current and voltage terminals integrated into the circuit, whereby the changing magnetic field can be measured without diminution by said eddy currents.

Claims

1. A metallic leadframe structure for use with a semiconductor chip intended for operation in a changing magnetic field, comprising:

a chip mount pad having at least one slit penetrating the whole thickness of said pad and substantially traversing the area of said pad from one edge to the opposite edge; and

said slit wide enough to interrupt electron flow in the pad plane, but not wide enough to significantly reduce thermal conduction in a direction normal to said pad plane, whereby said slit is operable to disrupt eddy currents induced in said pad by said changing magnetic field;

said device further comprising a chip wherein said chip has an integrated circuit including a Hall device.

2. The leadframe according to claim 1 wherein said slit has a width from about 0.01 to 0.5 mm.

3. The leadframe according to claim 1 wherein said structure comprises a sheet-like starting configuration having a thickness in the range from about 100 to 300 μ

m.

4. The leadframe according to claim 3 wherein said sheet-like starting configuration is selected from a group of metals consisting of copper, copper alloy, brass, aluminum, iron-nickel alloy, and invar.

5. The leadframe according to claim 1 wherein said pad has an area larger than said chip intended for mounting.