Electric contact and socket for electric parts

Patent metadata

Field	Value
Publication number	US-10096923-B2
Application number	US-201314405974-A
Country	US
Kind code	B2
Filing date	May 28, 2013
Priority date	Jun 6, 2012
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

An electric contact for preventing a terminal of an electric part and the electric contact from sticking to each other after a continuity test to improve the durability of the electric contact; and a socket for electric parts using the electric contact. The electric contact of this invention includes a first layer made from a material into which Sn melts and diffuses upon application of heat; and a second layer formed on the outer side of the first layer and made from a material lower in the rate at which Sn melts and diffuses upon application of heat than the first layer.

First claim

The invention claimed is:

1. An electric contact used to conduct a continuity test in a high temperature environment by being brought into contact with an Sn-containing terminal of an electric part, the electric contact comprising:
a first layer having a first Sn-diffusion rate into which Sn is to melt and diffuse at the first Sn-diffusion rate, while the electric contact is brought into contact with the Sn-containing terminal of the electric part to conduct the continuity test of the electric part upon application of heat in a high temperature range of about 125° C. to about 180° C.; and
a second layer having a second Sn-diffusion rate formed on an outer side of the first layer, into which the Sn melts and diffuses at the second Sn-diffusion rate lower than the first Sn-diffusion rate of the first layer, upon application of the heat of the continuity test while the second layer is brought into contact with the Sn-containing terminal of the electric part,
wherein
a thickness of the first layer is within a range of 0.2 μm to about 5 μm so that the Sn melts and diffuses into the first layer at the first Sn-diffusion rate,
the first layer is a Pd layer or a Pd alloy layer, and
the second layer is an Ag alloy layer composed primarily of Ag and containing Au or Cu in addition to the Ag, to provide a weight ratio of the Au or Cu being lower than the Ag so that the Sn melts and diffuses into the second layer at the second Sn-diffusion rate lower than the first Sn-diffusion rate of the first layer to retard Sn diffusion into the first layer.

2. The electric contact according to claim 1 , further comprising a base material having electrical conductivity and a foundation layer formed on an outer side of the base material and composed primarily of Ni,
wherein
the first layer is formed on an outer side of the foundation layer, and
the second layer is formed on the outer side of the first layer.

3. The electric contact according to claim 1 , comprising a base material serving as the first layer,
wherein the second layer is formed on an outer side of the base material.

4. A socket for electric parts used to conduct a continuity test in a high temperature environment, comprising:
a socket body;
a housing portion in which an electric part provided with an Sn-containing terminal is housed; and
an electric contact disposed in the socket body and placed in contact with the Sn-containing terminal,
wherein
a first layer having a first Sn-diffusion rate into which Sn melts and diffuses at the first Sn-diffusion rate upon application of heat and a second layer having a second Sn-diffusion rate formed on an outer side of the first layer are formed on a surface of the electric contact, into which the Sn melts and diffuses at the second Sn-diffusion rate lower than the first Sn-diffusion rate of the first layer upon application of heat of the continuity test when the electric contact is brought into contact with the Sn-containing terminal of the electric part and the continuity test of the electric part is conducted in a high temperature range of about 125° C. to about 180° C.,
a thickness of the first layer is within a range of 0.2 μm to about 5 μm so that the Sn melts and diffuses into the first layer at the first Sn-diffusion rate,
the first layer is a Pd layer or a Pd alloy layer, and
the second layer is an Ag alloy layer composed primarily of Ag and containing Au or Cu in addition to Ag, a weight ratio of the Au or Cu is lower than that of the Ag so that the Sn melts and diffuses into the second layer at the second Sn-diffusion rate lower than the first Sn-diffusion rate of the first layer to retard Sn diffusion into the first layer.

5. An electric contact used to conduct a continuity test in a high temperature environment by being brought into contact with an Sn-containing terminal of an electric part, the electric contact comprising:
a first layer having a first Sn-diffusion rate into which Sn is to melt and diffuse at the first Sn-diffusion rate, while the electric contact is brought into contact with the Sn-containing terminal of the electric part to conduct the continuity test of the electric part upon application of heat in a high temperature range of about 125° C. to about 180° C.; and
a second layer having a second Sn-diffusion rate formed on an outer side of the first layer, into which the Sn melts and diffuses at a second diffusion rate lower than the first diffusion rate of the first layer upon application of the heat of the continuity test while the second layer is brought into contact with the Sn-containing terminal of the electric part,
wherein
a thickness of the first layer is within a range of 0.2 μm to about 5 μm so that the Sn melts and diffuses into the first layer at the first Sn-diffusion rate,
the first layer is a Pd alloy layer composed primarily of Pd and containing Cu in addition to the Pd, to provide a weight ratio of Cu being lower than the Pd, and
the second layer is an Ag layer or an Ag alloy layer so that the Sn melts and diffuses into the second layer at the second Sn-diffusion rate lower than the first Sn-diffusion rate of the first layer to retard Sn diffusion into the first layer.

6. The electric contact according to claim 5 , further comprising a base material having electrical conductivity and a foundation layer formed on an outer side of the base material and composed primarily of Ni,
wherein the first layer is formed on an outer side of the foundation layer, and the second layer is formed on the outer side of the first layer.

7. The electric contact according to claim 5 , comprising a base material serving as the first layer, wherein the second layer is formed on an outer side of the base material.

8. A socket for electric parts used to conduct a continuity test in a high temperature environment, comprising:
a socket body;
a housing portion in which an electric part provided with an Sn-containing terminal is housed; and
an electric contact disposed in the socket body and placed in contact with the Sn-containing terminal,
wherein
a first layer having a first Sn-diffusion rate into which Sn melts and diffuses at the first Sn-diffusion rate upon application of heat and a second layer having a second Sn-diffusion rate formed on an outer side of the first layer are formed on a surface of the electric contact, into which the Sn melts and diffuses at the second Sn-diffusion rate lower than the first Sn-diffusion rate of the first layer upon application of heat of the continuity test when the electric contact is brought into contact with the Sn-containing terminal of the electric part and the continuity test of the electric part is conducted in a high temperature range of about 125° C. to about 180° C.,
a thickness of the first layer is within a range of 0.2 μm to about 5 μm so that the Sn melts and diffuses into the first layer at the first Sn-diffusion rate,
the first layer is a Pd alloy layer composed primarily of Pd and containing Cu in addition to Pd, a weight ratio of Cu is lower than the Pd, and
the second layer is an Ag layer or an Ag alloy layer so that the Sn melts and diffuses into the second layer at the second Sn-diffusion rate lower than the first Sn-diffusion rate of the first layer to retard Sn diffusion into the first layer.

9. An electric contact used to conduct a continuity test in a high temperature environment by being brought into contact with an Sn-containing terminal of an electric part, the electric contact comprising:
a first layer having a first Sn-diffusion rate into which Sn melts and diffuses at the first Sn-diffusion rate upon application of heat when the electric contact is brought into contact with the Sn-containing terminal of the electric part and the c

Assignees

• Enplas Corp

Inventors

• Oda Takahiro

Classifications

• G01R3/00

  Apparatus or processes specially adapted for the manufacture {or maintenance} of measuring instruments {, e.g. of probe tips} · CPC title

• C22C13/00

  Alloys based on tin · CPC title

• H01R13/03 Primary

  characterised by the material, e.g. plating, or coating materials · CPC title

• Y10T428/12708

  Sn-base component · CPC title

• B23K35/262

  Sn as the principal constituent · CPC title