INSULATED CURRENT SENSOR

• US 20200132728A1
• Filed: 10/24/2019
• Published: 04/30/2020
• Est. Priority Date: 10/24/2018
• Status: Active Grant

• Current Assignee: Melexis Technologies SA
• Original Assignee: Melexis Technologies SA
• Inventors: BOURY, Bruno, RACZ, Robert, CHEN, Jian, CACCIATO, Antonio
• Granted Patent: US 11,506,688 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 15/148 involving the measuring of a magnetic field or electric field G01R15/18, G01R15/20, G01R15/24, G01R15/26 take precedence
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• 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 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 2924/181 Encapsulation
• CPC Class Codes: H10N 52/01 Manufacture or treatment
• CPC Class Codes: H10N 52/101 Semiconductor Hall-effect devices
• CPC Class Codes: H10N 52/80 Constructional details

Abstract

A circuit for sensing a current comprises a substrate having a first and a second major surface, the second major surface being opposite to the first major surface. At least one magnetic field sensing element is arranged on the first major surface of the substrate and is suitable for sensing a magnetic field caused by a current flow in a current conductor coupled to the second major surface. The substrate also comprises at least one insulation layer, substantially buried between the first major surface and the second major surface of the substrate.

Claims

1. A circuit for sensing current, the circuit comprising:

a substrate having a first and a second major surface, the second major surface being opposite to the first major surface;

at least one magnetic field sensing element arranged on said first major surface of the substrate and suitable for sensing a magnetic field caused by a current flow in a current conductor coupled to the second major surface;

wherein the substrate comprises a first insulation layer positioned between the first major surface and the second major surface such that it is substantially buried in the substrate.

2. The circuit according to claim 1, wherein the substrate is a semiconductor-insulator-semiconductor substrate, wherein the insulator forms the first insulation layer.

3. The circuit according to claim 1, further comprising an insulating tape coupled to the second major surface.

4. The circuit according to claim 1, further comprising a leadframe comprising a primary and a secondary portion,

the primary and secondary portion each comprising a plurality of leads,

wherein at least two of the leads of the primary portion of the leadframe are electrically connected to each other to form a current conductor.

5. The circuit according to claim 1, wherein a thickness of the substrate is reduced in the vicinity of the at least one magnetic field sensing element.

6. The circuit according to claim 5, wherein a cavity is formed at the second major surface and in the vicinity of the at least one magnetic field sensing element.

7. The circuit according to claim 6, wherein the cavity comprises chamfered side walls and/or straight side walls.

8. The circuit according to claim 6, further comprising a leadframe comprising a primary and a secondary portion,

the primary and secondary portion each comprising a plurality of leads,

wherein at least two of the leads of the primary portion of the leadframe are electrically connected to each other to form a current conductor;

wherein the current conductor comprises a flat section and a protruding section, the flat section extending in a plane parallel to the second major surface, the protruding section extending out of said plane and into the cavity.

9. The circuit according to claim 4, wherein the substrate is resting only on the primary portion of the leadframe and does not overlap the secondary portion of the leadframe in a plan view parallel to the first major surface.

10. The circuit according to claim 1, wherein the substrate further comprises at least one second insulation layer positioned between the first major surface and the second major surface such that it is substantially buried in the substrate and not touching the first insulation layer.

11. The circuit according to claim 10, wherein a substrate material located between the first insulation layer and the second insulation layer is electrically grounded.

12. A method of manufacturing a device for measuring a current, the method comprising:

providing a semiconductor substrate having a first and a second major surface, the second major surface being opposite to said first major surface, and a first insulation layer which is, over at least part of its surface, buried in the substrate between said first and second major surface; and

providing at least one magnetic field sensing element on the first major surface, the magnetic field sensing element being suitable for sensing current flowing through a current conductor physically coupled to the second major surface.

13. The method according to claim 12, further comprising providing a current conductor and physically coupling the current conductor to the second major surface.

14. The method according to claim 13, wherein providing a current conductor comprises:

providing a flat leadframe including a plurality of leads;

connecting at least two leads of the plurality of leads so as to form said current conductor as a flat current conductor; and

etching a portion of the flat current conductor and/or using a stamping tool to form a protruding section along the flat current conductor.

15. The method according to claim 12, further comprising the step of etching a cavity into the semiconductor substrate, the cavity being etched at the second major surface and in the vicinity of the at least one magnetic field sensing element.