JPH0875820A - Graphite vapor-deposited contact pin and ic socket pin using this contact pin - Google Patents

Abstract

PURPOSE: To enhance the contact reliability and prolong the life. by vapor- depositing graphite on the surface of a contact pin. CONSTITUTION: Graphite vapor-deposition 11 is formed on the surface of a contact pin 20. The contact reliability and durability of the graphite vapor- deposited contact pin 20 or IC socket pin, which is repeatedly slid and attached/ detached, are enhanced. As means for forming vapor deposition of graphite, coating treatment by vacuum deposition with electron beams is one example. The socket pin having the graphite vapor deposition 11 has a function to prevent the formation of a gold-lead alloy on the surface of gold caused by sliding of the contact surface. As a result, the formation of tin oxide caused by remaining tin and oxygen in the air, which is a main cause to increase contact resistance, is suppressed. By the graphite vapor deposition 11, contact surface with less friction resistance can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a device under test I
The present invention relates to a coating means for a sliding surface that achieves a long life of electrical contact reliability of the contact pin contact surface in an IC socket or the like in which sliding and mounting is repeatedly performed between a C pin and a contact pin that is electrically connected.

[0002]

2. Description of the Prior Art In an IC tester, when a device under test (DUT) 50 is tested,
It is necessary to make electrical connection temporarily, and it has a contactor structure for this purpose. Among the contactor structures, there is a type in which the lead pins of the DUT 50 are slid to make an electrical connection, for example, an IC socket structure. In this IC socket type contactor, the contact resistance tends to increase because a physical change or a chemical change occurs on the contact surface due to a large number of sliding actions.

As an example of the conventional technique, there is a form in which the IC is electrically connected to the DUT 50. This will be described with reference to FIG. This contactor is composed of a test head section 40, an IC socket 30, a D
It consists of UT50. The test head unit 40 is I
IC socket 3 to which test signals from the C tester side correspond
It is connected to the socket pin 34 of 0 and supplies the voltage under test and the pattern under test. The DUT 50 is a device under test, and after being packaged in an IC container,
For the post-manufacturing inspection, all function test items are measured and implemented, and non-defective products / defective products are discriminated, and performance ranks are identified and sorted. IC lead pin 51 of DUT50
In general, the core material is made of copper nickel (CuNi) or iron nickel (FeNi) alloy, and the surface thereof is coated with solder.

The IC socket 30 comprises a socket housing 32 and a plurality of socket pins 34.
A socket corresponding to the UT50 package type is provided and used. The contact surface 35 of the socket pin 34 is plated with gold (Au) to form an electrode for obtaining stable electrical contact. The IC socket 30 is repeatedly attached to and detached from the DUT 50 for the above-mentioned test, and the electrical contact reliability and durability of the electrical contact portion are required. However, the contact surface 35 of the socket pin 34 of the IC socket 30 causes a chemical change of the contact surface due to repeated sliding, so that the contact resistance increases, resulting in poor contact or exceeding the allowable limit. It tends to become a resistance value. For this reason, the IC socket 30 is a consumable component that needs to be replaced after every use.

Physical changes and chemical changes of the contact surface 35 of the socket pin 34 will be described. When the IC socket 30 used tens of thousands of times is observed with a scanning microscope and a surface elemental analyzer, it is observed that the solder material covers the entire gold plating surface of the contact surface 35. As a result of surface elemental analysis of this portion, a mixture of solder (SnPb alloy) and its oxide, lead oxide (PbO) tin oxide (SnO2), is transferred and generated on the gold (Au) film of the contact surface 35. I understand. Here, due to the transfer and sliding action of the solder, a gold-lead (AuPb) alloy is formed on the gold (Au) surface of the contact surface 35 with the solder. Although this alloy itself is a conductor and does not affect the contact resistance, it plays the role of an adhesive between the solder material and the gold (Au) surface and promotes solder transition. The remaining solder component, tin, combines with oxygen in the air to form oxide tin oxide (SnO2). It is known that this tin oxide is a component that has a great adverse effect on contact resistance. Thus, it has been found that the chemical reaction between gold and solder results in the production of defective tin oxide (SnO2), which is the main cause of the increase in contact resistance.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, D
The IC lead pin 51 of the UT 50 and the contact surface 35 of the socket pin 34 are slid many times, so that the gold (Au) surface of the contact surface 35 has an IC socket pin 34
The solder coating on the surface is transferred and tin oxide (SnO)
The oxide of 2) is generated. As a result, a non-conductive film is formed on the surface, increasing the electrical resistance, for example, several Ω.
There are also things that lead to the above. Such contact resistance hinders the electrical test and has an adverse effect of causing an error in electrical measurement.

Therefore, the problem to be solved by the present invention is to improve the contact reliability and to prolong the life of the contact surface 35 of the socket pin 34 by subjecting the contact surface 35 of the socket pin 34 to a surface treatment that makes it difficult to form an insulating material. The purpose is to

[0008]

In order to solve the above-mentioned problems, in the constitution of the present invention, a means for coating the surface of the second contact pin 20 with the graphite vapor deposition 11 is used. As a result, the contact reliability and durability of the contact pin on which graphite is vapor-deposited or the contact pin of the IC socket pin that is repeatedly slidably attached and removed are improved. As a means for forming and depositing this graphite by vapor deposition, there is a means for performing coating treatment by vacuum vapor deposition by electron beam vapor deposition.

[0009]

The socket pin formed with the graphite vapor deposition 11 has the function of preventing the formation of a gold-lead (AuPb) alloy on the gold (Au) surface by sliding the contact surfaces. As a result, it has an effect of suppressing the formation of tin oxide (PbO2), which is the oxide of the remaining tin and oxygen in the air, which is the main factor of the increase in contact resistance. Also, graphite deposition 1
According to No. 1, a contact surface having a small frictional resistance can be obtained, and there is an action of reducing the adhesion / transfer of solder.

[0010]

EXAMPLE An example of the present invention is a case where graphite is deposited on the surface of a socket pin of the IC socket 30 to improve contact reliability. This will be described with reference to FIGS. 1 and 2A and 2B. The structure of the socket pin is the contact pin 20 and the gold plating 22.
And graphite vapor deposition 11. The contact pin 20 and the gold plating 22 are the same socket pin structure as the conventional one.

The graphite vapor deposition 11 is formed on the surface of the gold plating 22 by vacuum vapor deposition processing. Since graphite is a substance that does not easily evaporate, vacuum evaporation is performed by electron beam evaporation. Further, in order to form a graphite film having good conductivity, the formed graphite film is vapor-deposited in a state where the temperature of the contact pin 20 is raised to about 200 degrees.

In the socket pin thus formed, firstly, a contact surface having a small frictional resistance can be obtained, and
To obtain the effect of reducing the adhesion / transfer of solder, and thirdly,
The effect of suppressing the formation of an alloy with the gold plating 22 of the socket pin is obtained, and fourthly, the effect of stabilizing the contact resistance is obtained. The first frictional resistance is reduced to about half that of the conventional one. As a result, the wear of the contact surface due to the sliding and the transfer of the solder material from the IC lead pin 51 are reduced. The reduction of the adhesion / transfer of the second solder is shown in the comparative characteristic diagram of FIG. The horizontal axis represents the number of times of attachment and detachment, and the vertical axis represents the amount of transferred solder material. Compared with the conventional transfer amount characteristic 101a curve, in the present invention, the transfer amount characteristic 101b curve is half or less. The stabilization of the fourth contact resistance is shown in the comparative characteristic diagram of FIG. The horizontal axis represents the number of attachments and detachments, and the vertical axis represents the contact resistance value. As shown in the conventional contact resistance curve 102a,
In contrast to the contact resistance increasing from 2500 times or more, in the present invention, the stable and low contact resistance curve 102 is obtained.
It can be seen that b is maintained.

In the description of the above embodiment, the IC socket 30 is used.
In the above description, the graphite was vapor-deposited on the surface of the socket pin. However, in the form of a contact (contact) other than the above-mentioned embodiment, one is a gold contact surface and the other is a solder surface, and both are slid. It is also possible to make electrical connection, and the same operation can be performed.

[0014]

Since the present invention is configured as described above, it has the following effects. The socket pin with the graphite vapor deposition 11 is a DUT
By the sliding action of the IC lead pin 51 of 50 and the contact surface 35 of the socket pin 34, an effect of preventing the formation of a gold-lead (AuPb) alloy on the gold (Au) surface of the contact surface 35 is obtained. As a result, there is an effect of suppressing the formation of tin oxide (PbO2), which is the oxide of the remaining tin and oxygen in the air, which is the main cause of the increase in contact resistance. The socket pin on which the graphite vapor deposition 11 is formed has a contact surface with low frictional resistance, an effect of reducing solder adhesion / transition, and an effect of suppressing the formation of an alloy with the gold plating 22 of the socket pin. From these, a long life and stable contact resistance can be obtained. In the IC socket 30 that is repeatedly attached and detached by using this, electrical contact reliability and
Since the durability is improved and the frequency of replacing the IC socket 30 can be reduced, there is an advantage that the replacement cost can be reduced.

[0015]

[Brief description of drawings]

FIG. 1 is a cross-sectional view in which graphite is formed on a gold (Au) surface of a contact surface 35 of the present invention.

FIG. 2A is a comparative characteristic diagram of solder adhesion / dislocation with respect to the number of times of contact surface attachment / detachment. (B) is a comparative characteristic diagram of the contact resistance with respect to the number of times the contact surface is attached and detached.

FIG. 3 is a diagram illustrating a conventional use example in which an electric test is performed by electrically connecting a DUT 50 with an IC socket.

[Explanation of symbols]

 11 Graphite Vapor Deposition 20 Contact Pin 22 Gold Plating 30 IC Socket 32 Socket Housing 34 Socket Pin 35 Contact Surface 40 Test Head Part 50 Device Under Test (DUT) 51 IC Lead Pin 101a, 101b Transfer Rate Characteristic Curve 102a, 102b Contact Resistance Curve

Claims (3)

[Claims] 1. A contact pin in which the surface of a first contact material is coated with a SnPb alloy, which is a solder material, and the surface of a second contact material is coated with gold (Au). A contact pin, which is obtained by subjecting a surface of a second contact pin (20) to a coating process of graphite deposition (11) and having the above-mentioned features. 2. The surface of the first contact material is coated with a SnPb alloy, which is a solder material, and the surface of the contact material of the second IC socket (30) is coated with gold (Au), and both are repeatedly slid. In the detachable IC socket (30), the contact pin (20) of the second IC socket (30)
An IC socket pin on which graphite has been vapor-deposited, which is obtained by subjecting the surface of (1) to a coating treatment of graphite vaporization (11) and having the above. 3. The graphite-vapor-deposited contact pin according to claim 1 or 2, wherein the graphite is vapor-deposited by an electron beam vapor deposition method, and an IC socket pin using the same.