JP2013152237A - Contact pin with hybrid structure with precious metal plating layer formed on surface of high silicon and extra low carbon stainless steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact pin which can fulfill all five requirements: fine release characteristics from a solder ball, low electrical resistance (contact resistance and material resistance), high corrosion resistance and stable contact resistance, high hardness of parent material, and easy machining.SOLUTION: A contact pin 20 having a hybrid structure where a precious metal plating layer is formed on a surface of high silicon and extra low carbon stainless steel is a contact pin which is used by pressing a pin tip 22 against a solder ball. The contact pin 20 comprises: a contact pin body 30 manufactured from contact pin material made from the precipitation hardening type high silicon and extra low carbon stainless steel which has a Si (silicon) content within a range of 2-5 wt.% and a C (carbon) content of 0.03 wt.% or less as impurity; and a precious metal plating layer 32, which has a higher conductivity than that of the contact pin body 30, formed on a surface of the contact pin body 30.

Description

  The present invention relates to a contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / very low carbon stainless steel.

  The contact pin is a member used for a contact probe used for inspecting electrical characteristics of a semiconductor wafer, a semiconductor chip, and other electrical products. Conventionally, as such a contact pin, “releasability from a solder ball is good”, “electric resistance (contact resistance and material resistance) is low”, “corrosion resistance (or oxidation resistance) is high and contact resistance is high. Is stable, "the hardness of the base metal is high," "easily machined," and the like, from the viewpoint of satisfying the requirements such as "noble metal (BeCu) on the surface of the base material made of beryllium copper (BeCu)" Contact pins (for example, see Non-Patent Document 1 and Patent Document 1) formed with a plating layer (for example, a gold plating layer, a nickel base gold plating layer, or a rhodium plating layer) ”,“ a mother made of stainless steel (SUS304) ” Contact pins in which a noble metal plating layer is formed on the surface of the material (see, for example, Non-Patent Document 1), “Contact pins in which a noble metal plating layer is formed on the surface of a base material made of SK material (for example, , Refer to Non-Patent Document 1.) ", And" tungsten (W) contact pins made of (for example, see Patent Document 2.) "It is used.

JP 2007-85887 A JP 2006-98274 A

“Semiconductor Probes (Double Ended Probes)”, [online], Tespro Co., Ltd., [Search on March 26, 2010], Internet <URL: http://test-probe.jp/01/15/cat67/ 028mm032mm.html, http://test-probe.jp/01/15/cat66/010mm026mm.html, http://125.206.116.137/01/15/cat/sds-020-33l.html>

  By the way, contact pins are subject to contact failure due to oxidation of the tip of the pin due to repeated use, or contamination due to solder adhering to the tip of the pin due to repeated use. It is necessary to carry out. However, in the “contact pin in which a noble metal plating layer is formed on the surface of a base material made of beryllium copper (BeCu)”, since the hardness of the base material is low, the tip of the pin is worn by the cleaning process, and the contact There is a problem that the life of the pin is short.

  In addition, in “a contact pin having a noble metal plating layer formed on the surface of a base material made of stainless steel (SUS304)” or “a contact pin having a noble metal plating layer formed on the surface of a base material made of SK material”, Since the corrosion resistance of the material is not so high, there is a problem that contact resistance becomes high by repeated use, and stable inspection cannot be performed.

  Further, the contact pin used by pressing the pin tip against the solder ball has a pin tip cracking structure (for example, a pin tip four-splitting structure) in order to ensure stable contact with the solder ball. However, the “contact pin made of tungsten (W)” has a problem that the hardness is too high and machining is not easy, and it is difficult to form the above-described pin tip crack structure. There is also the problem of high material prices.

  In other words, in the conventional contact pin, “releasability from the solder ball is good”, “electric resistance (contact resistance and material resistance) is low”, “corrosion resistance is high and contact resistance is stable” All of the five requirements of “high hardness of the base material” and “easy to machine” could not be satisfied.

  Therefore, the present invention has been made in view of the circumstances as described above, and “releasability from solder balls is good”, “electrical resistance (contact resistance and material resistance) is low”, “corrosion resistance is high. The purpose is to provide a contact pin that can satisfy all of the five requirements of "high contact resistance and stability", "high hardness of the base material" and "easy machining". To do.

[1] The “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention is a contact pin used by pressing the tip of a pin against a solder ball. Precipitation hardening type high silicon and extremely low content in which the content of Si (silicon) is in the range of 2 to 5% by weight and the content of C (carbon) as an impurity is 0.03% by weight or less The contact pin main body manufactured from the contact pin raw material which consists of carbon stainless steel, and the noble metal plating layer which is formed in the surface of the said contact pin main body and has a higher electrical conductivity than the said contact pin main body, It is characterized by the above-mentioned.

  According to the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention, the contact pin main body has a “passive film formed on the surface”. Because it is manufactured from a contact pin material made of high silicon / ultra-low carbon stainless steel that “passive film is formed on the surface” as well as stainless steel due to low affinity with solder. Satisfies the requirement of good releasability from solder balls.

  In addition, according to the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention, after the cleaning process with the wire brush, The noble metal plating layer is removed and the contact pin body is exposed. However, the contact pin body has a Si (silicon) content in the range of 2 to 5% by weight and C as an impurity. Since it is manufactured from a contact pin material made of a precipitation hardening type high silicon / ultra low carbon stainless steel having a (carbon) content of 0.03% by weight or less, it is clear from the test examples described later. In addition, the contact pin body has a high corrosion resistance and is stable at a low contact resistance. As a result, the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention is stable in a value with high contact resistance and low contact resistance. Satisfy the requirement of

  This is because the “high silicon / ultra-low carbon stainless steel” used in the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel” of the present invention imparts corrosion resistance. Since it contains 2-5% by weight of Si (silicon), it has higher corrosion resistance than ordinary stainless steel, and furthermore, the passive film formed on the surface has the property of conducting electricity, so it can be used for a long time This is because the contact resistance is stabilized at a low value.

  Further, according to the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention, the contact pin body has a Si (silicon) content of 2 to 2. Manufactured from a contact pin material made of precipitation hardened high silicon / ultra-low carbon stainless steel having a C (carbon) content of 0.03% by weight or less within the range of 5% by weight. Therefore, as described above, the contact resistance of the contact pin is stable at a low value. Further, according to the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention, the noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel. Because of the formed hybrid structure, noble metal having higher conductivity than the contact pin body except for the tip of the pin on the surface of the contact pin body, even after performing the cleaning process with a wire brush. Since the plating layer is formed, the material resistance is also low. As a result, the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention requires “low electrical resistance (contact resistance and material resistance)”. Meet.

  Further, according to the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention, the contact pin body has a Si (silicon) content of 2 to 2. Manufactured from a contact pin material made of precipitation hardened high silicon / ultra-low carbon stainless steel having a C (carbon) content of 0.03% by weight or less within the range of 5% by weight. Therefore, since it is possible to increase the Vickers hardness Hv after the age hardening treatment to about 700, in the contact pin after the age hardening treatment, “the hardness of the base material” Satisfies the demand for “high”.

  This is because the “high silicon / ultra-low carbon stainless steel” used in the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel” of the present invention imparts corrosion resistance. Since Si (silicon) is contained in an amount of 2 to 5% by weight, the hardness of the base material can be increased even if the C (carbon) content is as low as 0.03% by weight or less. It is.

  Furthermore, according to the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention, the contact pin body has a Si (silicon) content of 2 Manufactured from a contact pin material made of a precipitation hardening type high silicon / ultra low carbon stainless steel having a content of C (carbon) as an impurity within a range of ˜5% by weight and 0.03% by weight or less. Therefore, the Vickers hardness Hv before performing the age hardening treatment can be set to about 400. For this reason, if the machining is performed before the age hardening treatment is performed, the machining can be easily performed, so that the requirement that “machining is easy” is satisfied.

  As a result, the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention has “good releasability from a solder ball”, “electric resistance Five requirements: "Low contact resistance and material resistance", "High corrosion resistance and stable contact resistance", "High hardness of base material" and "Easy machining" It becomes a contact pin that can satisfy all.

[2] In the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention, the contact pin body is machined on the contact pin material. It is preferable that the cured product is subjected to age hardening treatment.

  By setting it as such a structure, it becomes possible to form the pin front-end | tip part which has a pin front-end | tip crack structure by machining with respect to the contact pin raw material of a state with comparatively low hardness.

[3] The “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / very low carbon stainless steel” of the present invention preferably has a pin tip crack structure.

  With such a configuration, it is possible to obtain a contact pin having a structure suitable for being used by being pressed against a solder ball. Further, since the number of contact points increases, the contact resistance can be further reduced.

[4] In the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / very low carbon stainless steel” according to the present invention, the content of C (carbon) as an impurity is 0.015 wt. % Or less of high silicon / ultra-low carbon stainless steel is preferable.

  By adopting such a method, it is possible to further increase the corrosion resistance of the contact pin, and thus further increase the stability of the contact resistance.

[5] In the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention, the high silicon / ultra-low carbon stainless steel contains O as an impurity. It is preferably a high silicon / ultra-low carbon stainless steel having a content of (oxygen) of 0.005% by weight or less and a content of S (sulfur) as an impurity of 0.02% by weight or less. .

  By adopting such a configuration, it is possible to further increase the corrosion resistance of the contact pin, and further increase the stability of the contact resistance.

[6] In the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention, the high silicon / ultra-low carbon stainless steel is used in an electric furnace or a converter. It is preferably a high silicon / ultra-low carbon stainless steel produced by refining an iron-base alloy melted in a furnace in a vacuum atmosphere.

  By adopting such a configuration, it becomes possible to use a contact pin material made of high silicon / ultra-low carbon stainless steel with even less impurity content, so that the corrosion resistance of the contact pin can be further increased. As a result, the stability of the contact resistance can be further increased.

[7] In the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / very low carbon stainless steel” according to the present invention, the high silicon / very low carbon stainless steel is made of Si (silicon). 3.40-3.80 wt%, Cr (chromium) 10.20-10.60 wt%, Ni (nickel) 6.40-6.60 wt%, Mn (manganese) 0.80 1.00 wt%, Cu (copper) 0.90 to 1.10 wt%, Co (cobalt) 4.80 to 5.00 wt%, Mo (molybdenum) 1.40 to 1.60 wt% Nb (niobium) 3 wt% or less, Ta (tantalum) 3 wt% or less, Ti (titanium) 0.60 to 0.80 wt%, W (tungsten) 4 wt% or less, V (vanadium) Is 4% by weight or less, B (boron) is 0.01 % (%) Or less, Mg (magnesium) is 0.010% by weight or less, Ca (calcium) is 0.01% by weight or less, rare earth elements are 0.01% by weight or less, and the balance is Fe (iron) and impurities. It is an iron-based alloy, and C (carbon) as impurities is 0.02% by weight or less, P (phosphorus) is 0.03% by weight or less, S (sulfur) is 0.03% by weight or less, Al (aluminum) Is 0.03% by weight or less, N (nitrogen) is 0.05% by weight or less, O (oxygen) is 0.005% by weight or less, and H (hydrogen) is 0.0003% by weight or less. Carbon stainless steel is preferred.

  By adopting such a configuration, “excellent releasability from solder balls”, “low electrical resistance (contact resistance and material resistance)”, “high corrosion resistance and stable contact resistance” The contact pin is made of an optimum material as a contact pin that can satisfy all of the five requirements of “high hardness of the base material” and “easy to machine”.

The figure shown in order to demonstrate the contact pin 20 which concerns on Embodiment 1. FIG. 5 is a flowchart showing a manufacturing process of contact pins in the first embodiment. FIG. 5 is a perspective view showing a contact pin manufacturing process according to the first embodiment. The figure shown in order to demonstrate the effect of the contact pin which concerns on Embodiment 1. FIG. The figure shown in order to demonstrate the evaluation method in Test Examples 1-4. The figure which shows the evaluation result in Test Examples 1-4. It is a figure shown in order to demonstrate the evaluation method in Test Examples 5-8. The figure which shows the evaluation result in Test Examples 5-8. The figure which shows the evaluation result in Test Example 9 and 10.

  Hereinafter, the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” (hereinafter simply referred to as a contact pin) of the present invention is based on the embodiment shown in the drawings. I will explain.

[Embodiment 1]
1. Configuration of Contact Pin 20 FIG. 1 is a view for explaining the contact pin 20 according to the first embodiment. FIG. 1A is a front view of a contact probe 10 including a contact pin 20 as one of its constituent elements, FIG. 1B is a front view of the contact pin 20, and FIG. FIG. 1D is a perspective view of the contact pin 20 viewed from the side 22 and FIG. In FIG. 1A, reference numeral 40 indicates a pipe, reference numeral 42 indicates a spring in the pipe, and reference numeral 50 indicates a stopper.

  As shown in FIG. 1A, the contact pin 20 is a member used for a contact probe 10 used for inspection of electrical characteristics of a semiconductor wafer, a semiconductor chip, and other electrical products.

  As shown in FIG. 1B, the contact pin 20 has a pin tip portion 22 used by being pressed against a connection portion (for example, a solder ball; see FIG. 4C described later) in a product to be inspected (not shown). A pin base end portion 24 used for connection with a connection portion of an inspection apparatus (see FIG. 5 described later), and a connecting portion 26 that connects the pin tip end portion 22 and the pin base end portion 24. As shown in FIG. 1C, the contact pin 20 has a pin tip crack structure. The diameter of the contact pin 20 is, for example, 200 μm at the pin distal end portion 22 and the pin connecting portion 26, and is, for example, 240 μm at the pin proximal end portion 24. The length of the contact pin 20 is, for example, 1400 μm from the proximal end of the pin proximal end portion 24 to the distal end of the pin distal end portion 22.

  As shown in FIG. 1D, the contact pin 20 includes a contact pin body 30 and a noble metal plating layer 32 formed on the surface of the contact pin body 30.

  The contact pin main body 30 is a precipitation hardening type in which the content of Si (silicon) is in the range of 2 to 5% by weight and the content of C (carbon) as an impurity is 0.03% by weight or less. It is manufactured from a contact pin material made of high silicon and ultra-low carbon stainless steel. As high-silicon, ultra-low carbon stainless steel, high silicon, ultra-low carbon stainless steel (trade name: Siricolloy XVI), Silicolloy is a registered company of SII Techno. Trademark).

  Silicoloy XVI is 3.40-3.80 wt% Si (silicon), 10.20-10.60 wt% Cr (chrome), 6.40-6.60 wt% Ni (nickel), Mn (Manganese) is 0.80 to 1.00 wt%, Cu (copper) is 0.90 to 1.10 wt%, Co (cobalt) is 4.80 to 5.00 wt%, and Mo (molybdenum) is 1 .40 to 1.60 wt%, Nb (niobium) 3 wt% or less, Ta (tantalum) 3 wt% or less, Ti (titanium) 0.60 to 0.80 wt%, and Nb (niobium) 3 Wt% or less, Ta (tantalum) 3 wt% or less, W (tungsten) 4 wt% or less, V (vanadium) 4 wt% or less, B (boron) 0.01 wt% or less, Mg (magnesium) 0.010% by weight or less, Ca (calcium) 0.01% by weight Hereinafter, an iron-base alloy composed of 0.01% by weight or less of a rare earth element, the balance being Fe (iron) and impurities, wherein C (carbon) as an impurity is 0.02% by weight or less, P (phosphorus) Is 0.03% by weight or less, S (sulfur) is 0.03% by weight or less, Al (aluminum) is 0.03% by weight or less, N (nitrogen) is 0.05% by weight or less, and O (oxygen) is 0%. 0.005 wt% or less and H (hydrogen) is 0.0003 wt% or less.

  Therefore, in the contact pin 20, the high silicon / ultra-low carbon stainless steel has a Si (silicon) content of 3.40 to 3.80% by weight and a content of C (carbon) as an impurity. Is 0.02% by weight or less. Further, the high silicon / ultra-low carbon stainless steel has an O (oxygen) content of 0.005 wt% or less as an impurity and an S (sulfur) content of 0.02 wt% as an impurity. It is the following high silicon and ultra low carbon stainless steel. The high silicon / ultra-low carbon stainless steel is a high silicon / ultra-low carbon stainless steel produced by refining an iron-based alloy melted in an electric furnace or converter in a vacuum atmosphere.

  The noble metal plating layer 32 is made of a noble metal having a higher conductivity than the contact pin main body 30. Gold is used as the noble metal.

2. Contact Pin Manufacturing Method FIG. 2 is a flowchart showing a contact pin manufacturing process according to the first embodiment. FIG. 3 is a perspective view illustrating a manufacturing process of the contact pin in the first embodiment. FIG. 3A is a view showing the wire 60 prepared in the contact pin material preparation step S10, and FIG. 3B is a view showing the work member 62 after the outer shape processing step S22 is completed. ) Is an enlarged view of FIG. 3 (b), FIG. 3 (d) is a diagram showing the work-in-progress member 64 after the end quadruple cutting step S24, and FIG. 3 (e) is after the separation step S26. FIG. 3 (f) is a view showing the contact pin 20 after completion of the gold plating step S60. FIG. 3 (f) is a view showing the in-process member 66 (the one subjected to age hardening treatment is the contact pin main body 30). is there.

  As shown in FIG. 2, the contact pin 20 according to the first embodiment includes a “contact pin material preparation process”, a “machining process”, a “first cleaning process”, an “age hardening process process”, and a “second cleaning process”. ”And“ gold plating step ”can be performed in this order. Hereinafter, each manufacturing process will be described.

(1) Contact pin material preparation step S10
Diameter of high-silicon, ultra-low carbon stainless steel that has not been age-hardened as a contact pin material (high silicon, ultra-low carbon stainless steel (trade name: Silicoloy XVI) from S.I.Techno Co., Ltd.) A 0 mm wire 60 is prepared (see FIG. 3A). The Vickers hardness Hv of the wire 60 is about 400.

(2) Machining step S20
The machining step S20 includes an outer shape machining step S22, a four-end splitting step S24, and a separation step S26. In any of the processing steps S22, S24, and S26, since the Vickers hardness Hv of the wire is about 400, it can be easily processed using a normal processing apparatus.

(2-1) Outline processing step S22
With the lathe processing device, the wire 60 is subjected to outer shape processing, and the work-in-process member 62 is manufactured. The diameter of the work-in-progress member 62 is, for example, 200 μm at the pin distal end portion 22 and the pin connecting portion 26 and is, for example, 240 μm at the pin proximal end portion 24 (see FIGS. 3B and 3C).

(2-2) Four-end splitting process S24
An in-process member 64 is manufactured by subjecting one end of the in-process member 62 to four-end splitting by an NC processing machine. The work-in-process member 64 has a pin tip quadrant structure at one end, and has substantially the same shape as the contact pin main body 30 (see FIG. 3D).

(2-3) Separation processing step S26
The in-process member 64 is separated from the wire 60 by the lathe processing apparatus, and the in-process member 66 is manufactured. The in-process member 66 has substantially the same shape as the contact pin main body 30 (see FIG. 3E).

(3) First cleaning step S30
The in-process member 66 is cleaned by performing centrifugal barrel polishing and chemical cleaning. By performing the first cleaning step S30, the machining waste that may adhere to the surface in the machining step S20 is removed and the surface that may be roughened is smoothed.

(4) Age hardening treatment S40
The in-process member 66 is placed in a vacuum heat treatment furnace, and the in-process member 64 is subjected to age hardening treatment (sometimes referred to as precipitation hardening treatment) S40 at a temperature of 480 ° C. for 10 hours. To increase. By this age hardening treatment, the Vickers hardness Hv of the work-in-progress member 66 falls within the range of 650 to 750, and the work-in-process member 66 becomes the contact pin main body 30.

(5) Second cleaning step S50
The contact pin main body 30 is cleaned by performing chemical cleaning. By performing the second cleaning step S50, surface contamination that may occur when the contact pin main body 30 is subjected to the age hardening treatment S40 is removed.

(6) Gold plating step S60
By performing gold plating on the contact pin body 30, a gold plating layer 32 as a noble metal plating layer is formed on the surface of the contact pin body 30 (see FIG. 3F).

  The contact pin 20 according to the first embodiment can be manufactured through the above steps.

3. Effect of Contact Pin FIG. 4 is a diagram for explaining the effect of the contact pin according to the first embodiment. FIG. 4A is a diagram showing the state of the pin tip before the wire brush cleaning process is performed, and FIG. 4B is the pin tip after the wire brush cleaning process is performed. FIG. 4C is a diagram showing a state where the contact pin 20 and the solder ball 72 are in contact after the cleaning process using the wire brush is performed, and FIG. 4D is a diagram showing the contact at the time of inspection. FIG. 5 is a diagram for explaining an electrical resistance of a pin 20.

  According to the contact pin 20 according to the first embodiment, the contact pin main body 30 is “passive on the surface” in the same manner as the stainless steel whose affinity with the solder is low due to the formation of the passive film on the surface. Since the film is formed from a contact pin material made of high silicon / ultra-low carbon stainless steel, it satisfies the requirement of “good releasability from solder balls”.

  Further, according to the contact pin 20 according to the first embodiment, after the cleaning process using the wire brush, the noble metal plating layer 32 is removed at the pin tip portion 22 and the contact pin body 30 is exposed. (See FIG. 4B.) The contact pin body 30 has a Si (silicon) content of 2 to 5% by weight and a C (carbon) content of 0 as an impurity. Since the contact pin body is manufactured from a contact pin material made of precipitation hardening type high silicon / ultra low carbon stainless steel of 0.03 wt% or less, the corrosion resistance of the contact pin main body is evident from the test examples described later. High and stable with low contact resistance. As a result, the contact pin 20 according to the first embodiment satisfies the requirement that the contact pin has high corrosion resistance and is stable at a low contact resistance value.

  Further, according to the contact pin 20 according to the first embodiment, the contact pin body 30 has a Si (silicon) content in the range of 2 to 5% by weight, and contains C (carbon) as an impurity. Since it is manufactured from a contact pin material made of precipitation hardening type high silicon / ultra low carbon stainless steel having an amount of 0.03% by weight or less, as described above, the contact resistance of the contact pin is low. stable. In addition, according to the contact pin 20 according to the first embodiment, since it has a hybrid structure in which a noble metal plating layer is formed on the surface of high silicon / ultra-low carbon stainless steel, after performing a cleaning process with a wire brush, 4 (a) to 4 (c), a noble metal plating layer 32 having a higher conductivity than the contact pin body 30 is formed on the surface of the contact pin body except for the tip of the pin. Since it is formed, the material resistance is also low. As a result, the contact pin 20 according to the first embodiment satisfies the requirement “low electrical resistance (contact resistance R1 and material resistance R2 (both see FIG. 4D))”.

  Further, according to the contact pin 20 according to the first embodiment, the contact pin body 30 has a Si (silicon) content in the range of 2 to 5% by weight, and contains C (carbon) as an impurity. Since it is manufactured from a contact pin material made of precipitation hardening type high silicon / ultra low carbon stainless steel having an amount of 0.03% by weight or less, the Vickers hardness Hv after the age hardening treatment is 700 Since the contact pin after the age hardening treatment is performed, the requirement that the hardness of the base material is high is satisfied.

  Furthermore, according to the contact pin 20 according to the first embodiment, the contact pin main body 30 has a Si (silicon) content in the range of 2 to 5% by weight, and C (carbon) as an impurity. Since it is manufactured from a contact pin material made of a precipitation hardening type high silicon / ultra low carbon stainless steel having a content of 0.03% by weight or less, the Vickers hardness Hv before carrying out the age hardening treatment is It becomes possible to make it about 400. For this reason, if the machining is performed before the age hardening treatment is performed, the machining can be easily performed, so that the requirement that “machining is easy” is satisfied.

  As a result, the contact pin 20 according to the first embodiment has “good releasability from solder balls”, “low electrical resistance (contact resistance and material resistance)”, “high corrosion resistance and stable contact resistance. It is a contact pin that can satisfy all of the five requirements, that is, “the hardness of the base material is high” and “the machining is easy”.

  Further, according to the contact pin 20 according to the first embodiment, the contact pin main body 30 is hardened by subjecting the contact pin material to machine processing to age hardening, so that the pin tip crack structure It is possible to form the tip of the pin having a shape by machining a contact pin material having a relatively low hardness.

  Further, according to the contact pin 20 according to the first embodiment, since it has a pin tip crack structure (pin tip four-splitting structure), as shown in FIG. A contact pin having a suitable structure can be obtained. Further, since the number of contact points increases, the contact resistance can be further reduced.

  Further, according to the contact pin 20 according to the first embodiment, since the content of C (carbon) as an impurity is a high silicon / ultra-low carbon stainless steel having 0.015% by weight or less, the corrosion resistance of the contact pin is improved. It becomes possible to make it still higher, and as a result, the stability of the contact resistance can be made much higher.

  In addition, according to the contact pin 20 according to the first embodiment, the high silicon / ultra-low carbon stainless steel has a content of O (oxygen) as an impurity of 0.005% by weight or less and S as an impurity. (Sulfur) content of 0.02% by weight or less is a high silicon / ultra-low carbon stainless steel, which makes it possible to further increase the corrosion resistance of the contact pin and thus further improve the stability of the contact resistance. It becomes possible to make it higher.

  Further, according to the contact pin 20 according to the first embodiment, the high silicon / ultra-low carbon stainless steel is manufactured by refining an iron-base alloy melted in an electric furnace or converter in a vacuum atmosphere.・ Because it is an ultra-low carbon stainless steel, it is possible to use contact pin materials made of high silicon and ultra-low carbon stainless steel with even lower impurity content, so that the corrosion resistance of the contact pin is further increased. As a result, the stability of the contact resistance can be further increased.

  Furthermore, according to the contact pin according to the first embodiment, the high silicon / very low carbon stainless steel has a Si (silicon) of 3.40 to 3.80% by weight and a Cr (chrome) of 10.20 to 10. 60 wt%, Ni (nickel) 6.40-6.60 wt%, Mn (manganese) 0.80-1.00 wt%, Cu (copper) 0.90-1.10 wt%, Co (Cobalt) 4.80 to 5.00 wt%, Mo (molybdenum) 1.40 to 1.60 wt%, Nb (niobium) 3 wt% or less, Ta (tantalum) 3 wt% or less, Ti (Titanium) is 0.60 to 0.80% by weight, W (tungsten) is 4% by weight or less, V (vanadium) is 4% by weight or less, B (boron) is 0.01% by weight or less, Mg (magnesium) 0.010% by weight or less, Ca (calcium) 0.01 An iron-base alloy comprising rare earth elements in an amount of 0.01% by weight or less, the balance being Fe (iron) and impurities, wherein C (carbon) as impurities is 0.02% by weight or less, P ( Phosphorus) is 0.03% by weight or less, S (sulfur) is 0.03% by weight or less, Al (aluminum) is 0.03% by weight or less, N (nitrogen) is 0.05% by weight or less, O (oxygen) Is a high silicon / ultra-low carbon stainless steel having 0.005% by weight or less and H (hydrogen) of 0.0003% by weight or less, so that “releasability from solder balls is good”, “electric resistance ( All five requirements of "low contact resistance and material resistance", "high corrosion resistance and stable contact resistance", "high hardness of base material" and "easy machining" Contour made of the most suitable material for contact pins that can be filled The Topin.

[Embodiment 2]
The contact pin 20a (not shown) according to the second embodiment basically has the same configuration as the contact pin 20 according to the first embodiment, but the composition of the high silicon / ultra-low carbon stainless steel is the first embodiment. This is different from the contact pin 20 according to FIG. That is, in the contact pin 20a according to the second embodiment, high silicon / ultra-low carbon stainless steel (trade name: Silicoloy A2) manufactured by SII Techno Co., Ltd. is used as the high silicon / ultra-low carbon stainless steel.

  Silicoloy A2 is 3.00 to 5.00% by weight of Si (silicon), 10.00 to 13.00% by weight of Cr (chromium), 6.00 to 7.00% by weight of Ni (nickel), Mn (Manganese) is 0.50 to 1.50% by weight, Cu (copper) is 0.80 to 1.20% by weight, Mo (molybdenum) is 0.30 to 1.00% by weight, and Nb (niobium) is 0. .30 to 1.00% by weight, the balance being an iron-based alloy composed of Fe (iron) and impurities, C (carbon) as impurities being 0.02% by weight or less, and P (phosphorus) being 0.04 It is a high silicon / ultra-low carbon stainless steel having a weight% or less and S (sulfur) of 0.03% or less.

  Thus, the contact pin 20a according to the second embodiment is different from the contact pin 20 according to the first embodiment in the composition of high silicon / ultra-low carbon stainless steel, but the content of Si (silicon) is 2 to 2. Manufactured from a contact pin material made of precipitation hardened high silicon / ultra-low carbon stainless steel having a C (carbon) content of 0.03% by weight or less within the range of 5% by weight. Since the contact pin main body and the noble metal plating layer formed on the surface of the contact pin main body and having a higher conductivity than the contact pin main body are provided, as in the case of the contact pin 20 according to the first embodiment, “solder ball Good mold releasability ”,“ low electrical resistance (contact resistance and material resistance) ”,“ high corrosion resistance and stable contact resistance ”,“ hardness of base material Ikoto "and the five contact pins which can satisfy all the requirements of" that machining is easy. "

  The contact pin 20a according to the second embodiment has the same configuration as that of the contact pin 20 according to the first embodiment except for the composition of the high silicon / ultra-low carbon stainless steel, and therefore the contact pin according to the first embodiment. 10 has the corresponding effect.

[Test example]
Hereinafter, the present invention will be described in more detail with reference to test examples.

1. Test examples 1 to 4 (environmental reliability test 1)
Test Examples 1 to 4 show that the high silicon / ultra-low carbon stainless steel used for the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel” of the present invention is “corrosion resistant. It is a test example showing that the requirement that “the contact resistance is high and stable” is satisfied.

1-1. Preparation of sample After preparing a high silicon / ultra-low carbon stainless steel (trade name: Silicoloy XVI) purchased from SII Techno Co., Ltd. into a test piece having a width of 10 mm, a length of 50 mm and a thickness of 4 mm, The surface was cleaned to give Test Example 1. In addition, after preparing a high silicon / ultra-low carbon stainless steel (trade name: Silicoloy A2) purchased from SII Techno Co., Ltd. into a test piece having a width of 10 mm, a length of 50 mm and a thickness of 4 mm, the surface Was made into Test Example 2. Further, after preparing stainless steel SUS304 into a test piece having a width of 10 mm, a length of 50 mm, and a thickness of 4 mm, the surface was cleaned, and Test Example 3 was obtained. Further, after preparing stainless steel SUS304 into a test piece having a width of 10 mm, a length of 50 mm, and a thickness of 4 mm, the surface was cleaned, and further gold plating with extremely low contact resistance was applied to the surface. It was. Test examples 1 and 2 are examples, test example 3 is a comparative example, and test example 4 is a control example.

1-2. Evaluation Method FIG. 5 is a diagram for explaining an evaluation method in Test Examples 1 to 4.
As shown in FIG. 5, the test examples 1 to 4 are evaluated on the surface of the test piece W according to Test Examples 1 to 4 before and after the heat treatment for the environmental reliability test. The measurement was performed by measuring the resistance when the contact pin 120 "having a gold plating layer formed on the surface of a base material made of BeCu) was pressed under a predetermined pressure condition (30 g, 60 g, 90 g). That is, in Test Examples 1 to 3, as shown in FIG. 5A, the contact pin 120 and stainless steel (high silicon / very low carbon stainless steel or normal stainless steel) are in contact with each other. Thus, in Test Example 4, as shown in FIG. 5B, the resistance is measured under the condition where the contact pin 120 and the gold plating layer are in contact with each other.

  The heat treatment was performed by leaving the test pieces according to Test Examples 1 to 4 in a dryer at 150 ° C. for 100 hours. The resistance was measured using a contact resistance meter (LCR meter / trade name: AX-221N) manufactured by ADEX Co., Ltd. The pressure was set using a pressure measuring instrument (force gauge / trade name: Z2-2N) manufactured by Imada Corporation. A commercially available contact pin 120 having no pin tip crack structure was used.

1-3. Evaluation Results FIG. 6 is a diagram showing evaluation results in Test Examples 1 to 4.
As can be seen from FIG. 6, in the case of Test Example 3, the resistance is greatly increased by the heat treatment under any pressure condition (for example, 0.16Ω is increased even under the pressure condition of 90 g). On the other hand, in the case of Test Examples 1 and 2, the resistance did not increase so much by heat treatment under any pressure condition (for example, 0.05Ω (test in the case of 30 g pressure condition) Example 1) or 0.07Ω (Test Example 2) only increased.) From this result, the test piece (high silicon / very low carbon stainless steel) according to Test Examples 1 and 2 has a resistance change even by heat treatment as compared with the test piece according to Test Example 3 (ordinary stainless steel). It was found that it is small and satisfies the requirement of “high corrosion resistance and stable contact resistance”.

2. Test Examples 5 to 8 (electric resistance test)
Test Examples 5 to 8 show that the hybrid structure employed in the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention is “electrical resistance (contact resistance and material). It is a test example showing that the requirement of “resistance is low” is satisfied.

2-1. Preparation of Sample A contact pin body was made from a high silicon / ultra-low carbon stainless steel (trade name: Silicoloy XVI) purchased from SII Techno Co., Ltd., and then the surface was cleaned to obtain Test Example 5. Further, Test Example 6 was obtained by applying gold plating to the entire surface of the contact pin main body having the same configuration as Test Example 5. In addition, a contact pin body was made from a high silicon / ultra-low carbon stainless steel (trade name: Silicoloy A2) purchased from S.I.Techno Co., Ltd., and then the surface was cleaned. Test example 8 was obtained by applying gold plating to the entire surface of the contact pin main body having the same configuration as test example 7. Test examples 5 and 7 are comparative examples, and test examples 6 and 8 are examples. In each test example, a contact pin having no pin tip crack structure was produced as a contact pin body.

2-2. Evaluation Method FIG. 7 is a diagram for explaining an evaluation method in Test Examples 5 to 8.
As shown in FIG. 7, the test examples 5 to 8 are evaluated as follows. A flat plate (stainless steel SUS304 having a width of 10 mm, a length of 50 mm, and a thickness of 4 mm is the same as the test piece according to Test Example 4 described above. After preparing the material, the contact pin according to Test Examples 5 to 8 is subjected to a predetermined pressure condition (30 g) for the surface is cleaned and the surface is subjected to gold plating with extremely low contact resistance. This was done by measuring the resistance when pressed. That is, in Test Examples 5 and 7, the current flows through the contact pin body made of high silicon and extremely low carbon stainless steel, whereas in Test Examples 6 and 8, the current is high silicon and extremely low carbon. In addition to flowing through the contact pin main body made of stainless steel, a gold plating layer having a higher conductivity than the contact pin main body also flows.

  The resistance was measured using a contact resistance meter (LCR meter / trade name: AX-221N) manufactured by ADEX Co., Ltd. The pressure was set using a pressure measuring instrument (force gauge / trade name: Z2-2N) manufactured by Imada Corporation.

2-3. Evaluation Results FIG. 8 is a table showing the evaluation results for the test examples of Test Examples 5 to 8.
As can be seen from FIG. 8, in Test Examples 6 and 8, it was found that the resistance was greatly reduced compared to Test Examples 5 and 7 (both reduced by 0.11Ω). From this result, the contact pins according to Test Examples 6 and 8 (contact pins having a hybrid structure in which a noble metal plating layer is formed on the surface of high silicon / ultra-low carbon stainless steel) are the contact pins according to Test Examples 5 and 7. Comparison with (contact pin made of high silicon / ultra-low carbon stainless steel and not having a hybrid structure) revealed that the requirement “low electrical resistance (contact resistance and material resistance)” is satisfied.

3. Test examples 9 and 10 (environmental reliability test 2)
Test Examples 9 and 10 show that the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” of the present invention is “high in corrosion resistance and stable in contact resistance”. And a test example showing that the two requirements of “low electrical resistance (contact resistance and material resistance)” are satisfied.

3-1. Preparation of sample The contact pin body was made from high silicon / ultra-low carbon stainless steel (trade name: Silicoloy XVI) purchased from SII Techno Co., Ltd., the surface was cleaned, and then the surface was plated with gold. This was designated as Test Example 9. In addition, the contact pin body was made from high silicon, ultra-low carbon stainless steel (trade name: Silicoloy A2) purchased from S.I.Techno Co., Ltd., the surface was cleaned, and then the surface was plated with gold Was designated as Test Example 10. Test Examples 9 and 10 are examples.

3-2. Evaluation Method Evaluation for Test Examples 9 and 10 is performed after a flat plate (stainless steel SUS304 having a width of 10 mm, a length of 50 mm, and a thickness of 4 mm is prepared as the test piece according to Test Example 4 described above. The contact pins according to Test Examples 9 and 10 before and after the heat treatment for the environmental reliability test are applied at a predetermined pressure. It was performed by measuring the resistance when pressed under the conditions (30 g, 60 g, 90 g).

  The heat treatment was performed by leaving the contact pins according to Test Examples 9 and 10 in a dryer at 150 ° C. for 100 hours. The resistance was measured using a contact resistance meter (LCR meter / trade name: AX-221N) manufactured by ADEX Co., Ltd. The pressure was set using a pressure measuring instrument (force gauge / trade name: Z2-2N) manufactured by Imada Corporation.

3-3. Evaluation Results FIG. 9 is a table showing the evaluation results for the test examples of Test Examples 9 and 10.
As can be seen from FIG. 9, in any of the test examples 9 and 10, the resistance does not increase so much by heat treatment under any pressure condition (for example, 0.03Ω even under the pressure condition of 30 g). (Test Example 9) or 0.01Ω (Test Example 10) only increases.) Further, in any of Test Examples 9 and 10, the absolute value of the resistance is low under any pressure condition (for example, 0.17Ω (Test Example 9) or 0.18Ω under the pressure condition of 30 g). (Test Example 10)). From these results, the contact pins according to Test Examples 9 and 10 (contact pins having a hybrid structure in which a noble metal plating layer is formed on the surface of high silicon / ultra-low carbon stainless steel) are “high in corrosion resistance and stable in contact resistance. It has become clear that the two requirements of “being low” and “low electric resistance (contact resistance and material resistance)” are satisfied.

  As described above, the “contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of a high silicon / ultra-low carbon stainless steel” according to the present invention has been described based on each of the above-described embodiments. The present invention is not limited and can be carried out without departing from the gist thereof. For example, the following modifications are possible.

(1) In the above embodiments, high silicon / ultra-low carbon stainless steel (trade name: Silicoloy XVI and Silicoloy A2) of S.I.Techno Co., Ltd. was used as the high silicon / ultralow carbon stainless steel. However, the present invention is not limited to this. High silicon / ultra-low carbon stainless steel other than the above may be used.

(2) In each of the above embodiments, the gold plating layer is used as the noble metal plating layer formed on the surface of the contact pin main body 30, but the present invention is not limited to this. As the noble metal plating layer, a noble metal plating layer made of a noble metal other than gold may be used.

(3) In each of the above embodiments, the noble metal plating layer is formed directly on the surface of the contact pin main body 30, but the present invention is not limited to this. A noble metal plating layer may be formed on the surface of the contact pin main body 30 via a base plating layer (for example, a copper plating layer).

(4) In each of the above embodiments, the contact pins 20 and 20a are manufactured by the manufacturing method described above, but the present invention is not limited to this. You may use the manufacturing method different from the said each embodiment.

(5) In the above test examples 9 and 10, the environmental reliability test was performed using a contact pin having no pin tip crack structure (that is, a contact pin having one contact point). An environmental reliability test may be performed using the contact pin having the contact point, and in that case, the contact point is increased, and it is expected that a lower contact resistance and thus a lower electrical resistance can be obtained.

DESCRIPTION OF SYMBOLS 10 ... Contact probe, 20 ... Contact pin, 22 ... Pin front-end | tip part, 24 ... Pin base end part, 26 ... Pin connection part, 30 ... Contact pin main body, 32 ... Precious metal plating layer, 40 ... Pipe, 42 ... Spring, 50 ... stopper, 60 ... wire rod, 62, 64, 66 ... work-in-progress member, 70 ... device to be inspected, 72 ... solder ball, 80 ... inspection device, 100, 102, 200 ... contact resistance evaluation system, 110, 212 ... solder, 112, 122, 214, 220 ... connection line, 120 ... contact pin, 130 ... contact resistance meter, 210 ... flat plate, W ... each test example

Claims (7)

A contact pin used by pressing the tip of a pin against a solder ball,
Precipitation hardening type high silicon / very low carbon in which the content of Si (silicon) is in the range of 2 to 5% by weight and the content of C (carbon) as an impurity is 0.03% by weight or less. A contact pin body manufactured from a contact pin material made of stainless steel;
A noble metal plating layer is formed on a surface of a high silicon / ultra-low carbon stainless steel formed on the surface of the contact pin body and having a noble metal plating layer having a higher conductivity than the contact pin body. Contact pin with a hybrid structure.   2. The high silicon / ultra-low carbon stainless steel according to claim 1, wherein the contact pin main body is hardened by subjecting the contact pin material to machining to age hardening. 3. A contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the substrate.   The contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel according to claim 1, which has a pin tip crack structure.   The high silicon / ultra-low carbon stainless steel is a high silicon / ultra-low carbon stainless steel having a content of C (carbon) as an impurity of 0.015% by weight or less. A contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel according to any one of the above.   The high silicon / ultra-low carbon stainless steel has an O (oxygen) content of 0.005 wt% or less as an impurity and an S (sulfur) content of 0.02 wt% or less as an impurity. The contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel according to claim 4, wherein the contact pin is a high silicon / ultra-low carbon stainless steel.   The high silicon / ultra-low carbon stainless steel is a high silicon / ultra-low carbon stainless steel manufactured by refining an iron-base alloy melted in an electric furnace or converter in a vacuum atmosphere. A contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel according to claim 5.   The high silicon / ultra-low carbon stainless steel has Si (silicon) of 3.40 to 3.80 wt%, Cr (chrome) of 10.20 to 10.60 wt%, and Ni (nickel) of 6.40 to 6.60 wt%, Mn (manganese) 0.80 to 1.00 wt%, Cu (copper) 0.90 to 1.10 wt%, Co (cobalt) 4.80 to 5.00 wt% Mo (molybdenum) 1.40 to 1.60 wt%, Nb (niobium) 3 wt% or less, Ta (tantalum) 3 wt% or less, Ti (titanium) 0.60 to 0.80 wt% W (tungsten) is 4 wt% or less, V (vanadium) is 4 wt% or less, B (boron) is 0.01 wt% or less, Mg (magnesium) is 0.010 wt% or less, Ca (calcium) is 0.01 wt% or less, rare earth element is 0.01 wt% or less, Is an iron-based alloy composed of Fe (iron) and impurities, wherein C (carbon) as impurities is 0.02 wt% or less, P (phosphorus) is 0.03% wt% or less, and S (sulfur) is 0 0.03 wt% or less, Al (aluminum) 0.03 wt% or less, N (nitrogen) 0.05 wt% or less, O (oxygen) 0.005 wt% or less, and H (hydrogen) 0.0003 wt%. The contact pin having a hybrid structure in which a noble metal plating layer is formed on the surface of the high silicon / ultra-low carbon stainless steel according to claim 6, wherein the contact pin is a high silicon / ultra-low carbon stainless steel having a weight% or less. .

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