Semiconductor package with liquid metal conductors

Patent metadata

Field	Value
Publication number	US-10879151-B2
Application number	US-201816235419-A
Country	US
Kind code	B2
Filing date	Dec 28, 2018
Priority date	Dec 28, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A semiconductor package includes a lead frame, a semiconductor device, a liquid metal conductor, and an encapsulation material. The semiconductor device is affixed to the lead frame. The liquid metal conductor couples the semiconductor device to the lead frame. The encapsulation material encases the semiconductor device, the liquid metal conductor, and at least a portion of the lead frame.

First claim

What is claimed is:

1. A semiconductor package, comprising:
a lead frame;
a semiconductor device affixed to the lead frame;
a liquid metal conductor that couples the semiconductor device to the lead frame;
an encapsulation material that encases the semiconductor device, the liquid metal conductor, and at least a portion of the lead frame; and
a liquid metal heat sink configured to transfer heat from the semiconductor device to the lead frame.

2. The semiconductor package of claim 1 , wherein the liquid metal conductor comprises a eutectic alloy of gallium and indium.

3. A semiconductor package, comprising:
a lead frame;
a semiconductor device affixed to the lead frame;
a first liquid metal conductor that couples the semiconductor device to the lead frame;
an encapsulation material that encases the semiconductor device, the first liquid metal conductor, and at least a portion of the lead frame; and
a second liquid metal conductor that is: electrically connected to the lead frame and electrically isolated from the semiconductor device; or electrically connected to the semiconductor device and electrically isolated from the lead frame.

4. A semiconductor package, comprising:
a lead frame;
a semiconductor device affixed to the lead frame;
a liquid metal conductor that couples the semiconductor device to the lead frame, wherein the liquid metal conductor is helical in shape; and
an encapsulation material that encases the semiconductor device, the liquid metal conductor, and at least a portion of the lead frame.

5. The semiconductor package of claim 1 , wherein a diameter of the liquid metal conductor varies over a length of the liquid metal conductor.

6. A semiconductor package, comprising:
a lead frame;
a first semiconductor device affixed to the lead frame;
a first liquid metal conductor that couples the first semiconductor device to the lead frame;
an encapsulation material that encases the first semiconductor device, the first liquid metal conductor, and at least a portion of the lead frame;
a second semiconductor device; and
a second liquid metal conductor that couples the first semiconductor device to the second semiconductor device.

7. A semiconductor package, comprising:
a lead frame;
a semiconductor device affixed to the lead frame;
a liquid metal conductor that couples the semiconductor device to the lead frame, the liquid metal conductor comprising branches that connect the liquid metal conductor to respective different electrical contacts of: the semiconductor device; or the lead frame; and
an encapsulation material that encases the semiconductor device, the liquid metal conductor, and at least a portion of the lead frame.

8. A semiconductor package, comprising:
a lead frame;
a semiconductor device affixed to the lead frame by a layer of liquid metal sandwiched between the semiconductor device and the lead frame;
a liquid metal conductor that couples the semiconductor device to the lead frame; and
an encapsulation material that encases the semiconductor device, the liquid metal conductor, and at least a portion of the lead frame.

9. A semiconductor package, comprising:
a lead frame;
a semiconductor device affixed to the lead frame;
a liquid metal conductor that couples the semiconductor device to the lead frame, wherein the liquid metal conductor is a liquid metal bump; and
an encapsulation material that encases the semiconductor device, the liquid metal conductor, and at least a portion of the lead frame.

10. A method, comprising:
forming a conductor between a semiconductor device and a lead frame by at least:
dispensing a first portion of liquid metal that forms an electrically conductive connection with a conductive terminal of the semiconductor device;
dispensing a second portion of liquid metal that forms an electrically conductive connection with a conductive terminal of a lead frame; and
dispensing a third portion of liquid metal that forms a conductive track that is connected to the first portion of the liquid metal and to the second portion of the liquid metal; and

encasing the semiconductor device, the conductor, and at least a portion of the lead frame in an encapsulation material.

11. The method of claim 10 , further comprising affixing the semiconductor device to the lead frame by a layer of liquid metal prior to dispensing the first portion of the liquid metal.

12. The method of claim 10 , dispensing liquid metal to form a liquid metal interconnect that couples the semiconductor device to a different semiconductor device affixed to the lead frame.

13. The method of claim 10 , further comprising depositing liquid metal to form a liquid metal heat sink that thermally couples the semiconductor device to the lead frame.

14. The method of claim 10 , wherein:
dispensing the first portion of the liquid metal comprises positioning a dispensing nozzle to dispense the liquid metal onto the conductive terminal of the semiconductor device;
dispensing the third portion of the liquid metal comprises moving a dispensing nozzle along a path aligned to the track, and dispensing liquid metal from the nozzle during the moving; and
dispensing the second portion of the liquid metal comprises positioning a dispensing nozzle to dispense the liquid metal onto the conductive terminal of the conductive terminal of the lead frame.

15. The method of claim 10 , further comprising rupturing an oxide layer surrounding the liquid metal while dispensing the liquid metal onto the conductive terminal of the semiconductor device or the conductive terminal of the lead frame.

16. The method of claim 10 , further comprising applying a cleaning agent or flux to the liquid metal prior to dispensing the liquid metal onto the conductive terminal of the semiconductor device or the conductive terminal of the lead frame.

17. The method of claim 10 , further comprising dispensing liquid metal to form a conductive element that is: electrically connected to the lead frame and electrically isolated from the semiconductor device; or electrically connected to the semiconductor device and electrically isolated from the lead frame.

18. A semiconductor package, comprising:
a lead frame;
a semiconductor device affixed to the lead frame;
a liquid metal heat sink coupled to the lead frame and the semiconductor device, and configured to transfer heat from the semiconductor device to the lead frame; and
an encapsulation material encasing the semiconductor device, the liquid metal heat sink, and at least a portion of the lead frame.

19. The semiconductor package of the claim 18 , further comprising:
a liquid metal conductor that couples the semiconductor device to the lead frame.

20. The semiconductor package of claim 18 , further comprising a liquid metal conductor that is: electrically connected to the lead frame and electrically isolated from the semiconductor device; or electrically connected to the semiconductor device and electrically isolated from the lead frame.

Assignees

• Texas Instruments Inc

Inventors

• Parekh Dishit Paresh
• Cook Benjamin Stassen
• Revier Daniel Lee
• Bito Jo

Classifications

• H10W90/754

  between a chip and a stacked insulating package substrate, interposer or RDL · CPC title

• H10W74/15

  on active surfaces of flip-chip devices, e.g. underfills · CPC title

• H10W74/012

  of encapsulations on active surfaces of flip-chip devices, e.g. forming underfills · CPC title

• H10W72/30

  Die-attach connectors · CPC title

• H10W70/02

  of conductive package substrates serving as an interconnection, e.g. of metal plates (manufacture or treatment of leadframes H10W70/04) · CPC title