Contact structures with porous networks for solder connections, and methods of fabricating same

Patent metadata

Field	Value
Publication number	US-10531574-B2
Application number	US-201715858791-A
Country	US
Kind code	B2
Filing date	Dec 29, 2017
Priority date	Dec 31, 2014
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A contact pad includes a solder-wettable porous network (310) which wicks the molten solder (130) and thus restricts the lateral spread of the solder, thus preventing solder bridging between adjacent contact pads.

First claim

The invention claimed is:

1. An assembly comprising:
a first component comprising a substrate and circuitry supported by the substrate, the circuitry comprising one or more contact pads; and
a second component underlying the first component and comprising a substrate and circuitry supported by the substrate, the circuitry of the second component comprising one or more contact pads each of which is attached to an overlying contact pad of the first component by a connection comprising:
an open-pore porous network which, in top view, has a lateral boundary and fills an area inside the lateral boundary, the open-pore porous network having a porosity of at least 70%; and
solder in pores of the open-pore porous network;
wherein in the open-pore porous network, any solid material between any adjacent pores is electrically conductive.

2. The assembly of claim 1 wherein each said connection comprises a segment within which an entire exterior surface of the connection is in physical contact with first dielectric.

3. The assembly of claim 1 , wherein in at least one connection, the solder extends from a non-porous layer in the first component to a non-porous layer in the second component.

4. The assembly of claim 3 wherein the non-porous layers of the first and second components are metal layers.

5. The assembly of claim 1 wherein any solid material between any adjacent pores is metal.

6. The assembly of claim 1 wherein in at least one connection, the open-pore porous network extends from a non-porous layer in the first component to a non-porous layer in the second component.

7. The assembly of claim 6 wherein the non-porous layers of the first and second components are metal layers.

8. The assembly of claim 1 , wherein the solder does not reach at least one of the contact pads.

9. The assembly of claim 1 , wherein the open-pore porous network is nanoporous or mesoporous.

10. An assembly comprising:
a first component comprising circuitry comprising one or more first contact pads; and
a second component underlying the first component and comprising circuitry comprising one or more second contact pads each of which is attached to an overlying first contact pad by solder;
wherein each second contact pad comprises a porous protrusion comprising an open-pore porous network which, in top view, has a lateral boundary and has pores inside the lateral boundary that contain at least some of the solder, the porous protrusion being electrically conductive and having, in addition to pores, only electrically conductive material, the porous protrusion having a porosity of at least 70%.

11. The assembly of claim 10 wherein in at least one connection, the solder extends from a non-porous layer in the first component to a non-porous layer in the second component.

12. The assembly of claim 11 wherein the non-porous layers of the first and second components are metal layers.

13. The assembly of claim 10 wherein in at least one connection, the open-pore porous network extends from a non-porous layer in the first component to a non-porous layer in the second component.

14. The assembly of claim 13 wherein the non-porous layers of the first and second components are metal layers.

15. The assembly of claim 10 wherein any solid material between any adjacent pores is metal.

16. The assembly of claim 10 , wherein the open-pore porous network is a nanoporous or mesoporous.

Assignees

• Invensas Corp

Inventors

• Wang Liang
• Katkar Rajesh
• Shen Hong
• Uzoh Cyprian Emeka

Classifications

• H10W72/0198

  batch processes · CPC title

• H10W72/952

  comprising metals or metalloids, e.g. PbSn, Ag or Cu · CPC title

• H10W72/925

  Bond pads having a filler embedded in a matrix · CPC title

• H10W72/951

  Materials of bond pads · CPC title

• H10W72/942

  relative to underlying supporting features, e.g. bond pads, RDLs or vias · CPC title