Solder material, solder joint, and method of manufacturing the solder material

Patent metadata

Field	Value
Publication number	US-10173287-B2
Application number	US-201415327510-A
Country	US
Kind code	B2
Filing date	Aug 29, 2014
Priority date	Aug 29, 2014
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

Provided is a solder material which enables a growth of an oxide film to be inhibited. A solder ball which is a solder material is composed of a solder layer and a covering layer covering the solder layer. The solder layer is spherical and is composed of a metal material containing an alloy including Sn content of 40% and more. Otherwise the solder layer is composed of a metal material including Sn content of 100%. In the covering layer, a SnO film is formed outside the solder layer, and a SnO 2 film is formed outside the SnO film. A thickness of the covering layer is preferably more than 0 nm and equal to or less than 4.5 nm. Additionally, a yellow chromaticity of the solder ball is preferably equal to or less than 5.7.

First claim

The invention claimed is:

1. A solder material comprising:
a solder layer composed of either a metal material containing an alloy including Sn content of 40% and more, or a metal material including Sn content of 100%; and
a covering layer covering a surface of the solder layer,
wherein the covering layer includes a SnO film which is formed outside the solder layer and a SnO 2 film which is formed outside the SnO film,
a thickness of the covering layer is more than 0 nm and equal to or less than 4.5 nm,
a yellow chromaticity in L*a*b* color space is equal to or less than 5.7,
the solder material is a solder ball having a diameter of 1 to 1000 μm, and
the solder ball is a sphere.

2. The solder material according to claim 1 , wherein the solder layer comprises 0% or more and less than 4% of Ag, 0% or more and less than 1% of Cu, 0 ppm or more and less than 5 ppm of P, and 0 ppm or more and less than 20 ppm of Ge.

3. The solder material according to claim 1 , wherein in order to make a contained amount of Sn equal to or more than 40%,
(i) the solder layer contains a total amount of less than 1% of at least one element selected from the group consisting of Ni, Co, Fe, and Sb, or less than 1% of the respective elements and a total amount of less than 40% of at least one element selected from the group consisting of In and Bi, or less than 40% of either one of In and Bi and less than 20% of the other, or
(ii) the solder layer contains a total amount of less than 1% of at least one element selected from the group consisting of Ni, Co, Fe, and Sb, or less than 1% of the respective elements, or a total amount of less than 40% of at least one element selected from the group consisting of In and Bi, or less than 40% of either one of In and Bi and less than 20% of the other.

4. The solder material according to claim 1 , wherein an alpha dose to be radiated is equal to or less than 0.0200 cph/cm 2 .

5. A method of manufacturing a solder material which is a spherical solder ball having a diameter of 1 to 1000 μm, wherein the method comprises:
a solder-layer-forming step of forming a solder layer, wherein a solder layer composed of either a metal material containing an alloy including Sn content of 40% and more, or a metal material including Sn content of 100% is formed, and
an oxide-film-forming step of forming a covering layer on a surface of the solder layer, wherein in the covering layer, a SnO film is formed outside the solder layer and a SnO 2 film is formed outside the SnO film, a thickness of the covering layer is more than 0 nm and equal to or less than 4.5 nm, and yellow chromaticity in L*a*b* color space of a surface of the covering layer is equal to or less than 5.7.

6. The method of manufacturing the solder material according to claim 5 , wherein in the oxide-film-forming step, O 2 —Ar plasma is discharged on the surface of the solder layer.

Assignees

• Senju Metal Industry Co

Inventors

• Kawasaki Hiroyoshi
• Roppongi Takahiro
• Soma Daisuke
• Sato Isamu
• Kawamata Yuji

Classifications

• C23C28/04

  only coatings of inorganic non-metallic material · CPC title

• C23C8/36

  using ionised gases, e.g. ionitriding · CPC title

• B23K35/26

  with the principal constituent melting at less than 400°C · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title

• B23K35/365

  Selection of non-metallic compositions of coating materials either alone or conjoint with selection of soldering or welding materials · CPC title