Integrated circuit package having a split lead frame

• US 9,666,788 B2
• Filed: 03/07/2013
• Issued: 05/30/2017
• Est. Priority Date: 03/20/2012
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: David, Paul, Vig, Ravi, Taylor, William P.
• Primary Examiner(s): Le, Son
• Application Number:
  US13/788,210
• Publication Number:
  US 20130249027A1
• Time in Patent Office: 1,545 Days
• CPC Class Codes: G01R 33/0011 comprising means, e.g. flux concentrators, flux guides, for guiding or concentrating the magnetic flux, e.g. to the magnetic sensor
• CPC Class Codes: G01R 33/0047 Housings or packaging of magnetic sensors packaging of semiconductor devices H01L23/00; Holders
• CPC Class Codes: G01R 33/0052 Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips devices based on galvano-magnetic effect or the like H10N50/85
• 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 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/4826 Connecting between the body and an opposite side of the item with respect to the body
• 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 2924/19105 in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H10N 50/80 Constructional details

Abstract

A magnetic field sensor includes a lead frame having a plurality of leads, at least two of which have a connection portion and a die attach portion. A semiconductor die is attached to the die attach portion of the at least two leads. The sensor further includes at least one wire bond coupled between the die and a first surface of the lead frame. The die is attached to a second, opposing surface of the lead frame in a lead on chip configuration. In some embodiments, at least one passive component is attached to the die attach portion of at least two leads.

Claims

1. A magnetic field sensor comprising:

a lead frame having a first surface, a second opposing surface, and comprising a plurality of leads, wherein at least two of the plurality of leads are electrically isolated from each other and wherein each of the at least two leads has a connection portion extending adjacent to the connection portion of the other one of the at least two leads and a die attach portion having a width larger than a width of the respective connection portion;

a semiconductor die having a first surface supporting a magnetic field sensing element and at least two bond pads, wherein the first surface is disposed proximal to and attached to the die attach portions of the at least two electrically isolated leads, and a second opposing surface is disposed distal from the die attach portions of the at least two electrically isolated leads, wherein the die attach portion of each of the at least two electrically isolated leads has a reduced area with respect to other areas of the die attach portion, wherein the reduced area is opposite and adjacent to a reduced area of the die attach portion of the other one of the at least two electrically isolated leads, and wherein the magnetic field sensing element and the at least two bond pads are disposed between the reduced area of the die attach portions of the at least two electrically isolated leads;

a non-conductive adhesive disposed between the semiconductor die and the die attach portion of the at least two electrically isolated leads;

at least one wire bond coupled between at least one of the at least two bond pads of the die and the first surface of the lead frame, wherein the die is attached to the second surface of the lead frame;

a non-conductive mold material enclosing the semiconductor die and the die attach portion of the at least two electrically isolated leads;

wherein any connection portions of any of the plurality of leads extending beyond the non-conductive mold material extend from a single side of the non-conductive mold material; and

a ferromagnetic mold material secured to a portion of the non-conductive mold material.

2. The magnetic field sensor of claim 1 further comprising a passive component coupled between the at least two leads.

3. The magnetic field sensor of claim 2 wherein the passive component is a capacitor.

4. The magnetic field sensor of claim 2 wherein the passive component is attached to the die attach portion of the at least two leads adjacent to the first surface of the lead frame.

5. The magnetic field sensor of claim 4 further comprising at least two passive components, each coupled between a respective pair of die attach portions.

6. The magnetic field sensor of claim 2 wherein the passive component is coupled to the connection portion of the at least two leads.

7. The magnetic field sensor of claim 1 further comprising a ferromagnetic mold material secured to the connection portion of at least one of the plurality of leads.

8. A magnetic field sensor comprising:

a lead frame having a first surface, a second opposing surface, and comprising a plurality of leads, wherein at least two of the plurality of leads are electrically isolated from each other and wherein each of the at least two leads has a connection portion extending adjacent to the connection portion of the other one of the at least two leads and a die attach portion having a width larger than a width of the respective connection portion;

a semiconductor die having a first surface supporting a magnetic field sensing element and at least two bond pads, wherein the first surface is disposed proximal to and attached to the die attach portion of the at least two electrically isolated leads, and a second opposing surface is disposed distal from the die attach portions of the at least two electrically isolated leads, wherein the die attach portion of each of the at least two electrically isolated leads has a reduced area with respect to other areas of the die attach portion, wherein the reduced area is opposite and adjacent to a reduced area of the die attach portion of the other one of the at least two electrically isolated leads, and wherein the magnetic field sensing element and the at least two bond pads are disposed between the reduced area of the die attach portions of the at least two electrically isolated leads;

a non-conductive adhesive disposed between the semiconductor die and the die attach portion of the at least two electrically isolated leads;

at least one wire bond coupled between at least one of the at least two bond pads of the die and the first surface of the lead frame, wherein the die is attached to the second surface of the lead frame;

a passive component coupled to at least two of the plurality of leads adjacent to the first surface of the lead frame, wherein the semiconductor die extends under the passive component; and

a non-conductive mold material enclosing the semiconductor die and the die attach portion of the at least two leads, wherein the non-conductive mold material has a diameter of less than approximately 7.0 mm.

9. The magnetic field sensor of claim 8 wherein the passive component is a capacitor.

10. The magnetic field sensor of claim 9 wherein the capacitor is attached to the die attach portion of the at least two leads.