LPS solder paste based low cost fine pitch pop interconnect solutions

Patent metadata

Field	Value
Publication number	US-9831206-B2
Application number	US-201414229785-A
Country	US
Kind code	B2
Filing date	Mar 28, 2014
Priority date	Mar 28, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

Embodiments describe high aspect ratio and fine pitch interconnects for a semiconductor package, such as a package-on-package structure. In an embodiment, the interconnects are formed with a no-slump solder paste. In an embodiment, the no-slump solder paste is printed in an uncured state, and is then cured with a liquid phase sintering process. After being cured, the no-slump solder paste will not reflow at typical processing temperatures, such as those below approximately 400° C. According to embodiments, the no-slump solder paste includes Cu particles or spheres, a solder matrix component, a polymeric delivery vehicle, and a solvent. In an embodiment, the liquid phase sintering produces a shell of intermetallic compounds around the Cu spheres. In an embodiment, the sintering process builds a conductive metallic network through the no-slump solder paste.

First claim

What is claimed is:

1. A semiconductor package comprising:
a first substrate having a plurality of first contact pads formed on an interior region of the first substrate and a plurality of second contact pads formed on a peripheral region of the first substrate;
a first device die comprising a plurality of first bonding pads, each electrically coupled to one of the first contact pads by a solder bump; and
a second substrate positioned above the first device die, and having a plurality of second bonding pads, each electrically coupled to one of the second contact pads by an interconnect comprising a no-slump solder paste and having an aspect ratio of 2:1 or greater, and wherein the no-slump solder paste comprises a conductive network formed by particles of a high-melting point metal, a solder matrix including an alloy of two or more elements, and a delivery vehicle, wherein the particles of the high-melting point metal are separated from the delivery vehicle by intermetallic compound shells that surround the high-melting point metal and are formed from the solder-matrix material and the high-melting point metal, and wherein the solder matrix forms conductive bridges between the high-melting point metal particles, and wherein each interconnect comprises unsupported sidewalls.

2. The semiconductor package of claim 1 , wherein the particles of the high-melting point metal are copper particles, the solder matrix is a SnBi solder, and the delivery vehicle comprises a polymer matrix.

3. The semiconductor package of claim 1 , wherein the interconnects have a height greater than 400 μm.

4. The semiconductor package of claim 1 , wherein the interconnects have a pitch less than 0.35 mm.

5. The semiconductor package of claim 1 , wherein the interconnects comprise a first portion and a second portion, wherein the first portion is bonded and electrically coupled to the second portion.

6. The semiconductor package of claim 5 , wherein the first portion and the second portion are a no-slump solder paste comprising copper particles, a solder material, and a delivery vehicle.

7. The semiconductor package of claim 5 , wherein the first portion is a solder bump and the second portion is a no-slump solder paste comprising copper particles, a solder material, and a delivery vehicle.

8. The semiconductor package of claim 5 , wherein the first portion is a no-slump solder paste comprising copper particles, a solder material, and a polymer matrix, and the second portion is a solder bump.

Assignees

• Intel Corp

Inventors

• Raravikar Nachiket R
• Matayabas Jr James C
• Mathkar Akshay

Classifications

• B23K35/3033

  Ni as the principal constituent · CPC title

• B23K35/025

  Pastes, creams or slurries · CPC title

• B23K35/3613

  Polymers, e.g. resins · CPC title

• B23K2101/40

  Semiconductor devices · CPC title

• B23K35/262

  Sn as the principal constituent · CPC title