JP2012018869A - Electric contact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric contact in which high stress concentration is obtained even with a low load or a low contact pressure in the order of 0.098-0.147 N by specifying the optimal range of radius clearly at the tip of a protrusion constituting a contact, while lowering contact resistance at the contact with a contact object and reducing variation thereof.SOLUTION: An electric contact 1 has a contact part 3 which comes into contact with a conductive conductor pattern (a contact object) of a counter substrate 10. At least a pair of protrusions 5a protruding from the contact surface 4 with the contact object in the contact part 3 and constituting a contact with the contact object are provided on the contact surface 4. Radius R at the tip of each protrusion 5a is 5-15 μm.

Description

  The present invention relates to an electrical contact that contacts a contacted object having conductivity such as a conductor pattern of a circuit board or a mating contact.

2. Description of the Related Art Conventionally, an electrical connector is known that includes an electrical contact that contacts a contacted object having conductivity such as a conductor pattern of a circuit board or a mating contact, and an insulating housing that supports the electrical contact.
As an example of this electrical connector, for example, an IC socket shown in FIG. 7 is known (see Patent Document 1). 7A and 7B show a conventional IC socket, in which FIG. 7A is a partial cross-sectional view showing a state where an IC package lead and an IC socket contact are connected, and FIG. 7B is an enlarged partial enlarged view showing an uneven portion of the contact. It is.

  The IC socket 101 shown in FIG. 7A includes at least one row of conductive contacts 120 that are in contact with the arranged leads 131 of the IC package 130, and an insulating housing 110 that supports the contacts 120. Yes. An IC package 130 is placed on the housing 110. When the IC package 130 is placed on the housing 110 of the IC socket 101, the contact portion 121 of the contact 120 contacts the lead 131 by wiping in the arrow W direction shown in FIG. 7B.

  The contact surface 122 of the contact portion 121 of each contact 120 with the lead 131 is provided with a plurality of ridges 123 extending in a direction perpendicular to the wiping direction (arrow W direction). The ridges 123 include a plurality of V-shaped grooves 123a that are recessed from the contact surface 122, and a plurality of pairs of ridges 123b along the grooves 123a on both sides of the grooves 123a. The uneven stripe 123 is formed by dragging in a direction orthogonal to the wiping direction (a direction orthogonal to the paper surface in FIG. 7B).

Then, as the dimension of these concave-convex 123, for example, the angle alpha ₁ is 60 degrees of the groove 123a, the depth _{h 1} is 0.08 mm, the distance _{d 1} between the ridges 123b is 0.09 mm, the cross-sectional area of the groove 123a S Is 0.037 mm ² , and the distance D ₁ between the grooves 123 a and 123 a is 0.020 mm.
By providing such a concavo-convex ridge 123, even if the amount of wiping is small when the contact 120 and the lead 131 are in contact with each other, the foreign matter having the property of extending is scraped off and removed by the concavo-convex ridge 36, and electrical connection is reliably performed. be able to.

As another example of a conventional electrical connector, for example, the one shown in FIG. 8 (see Patent Document 2) is known. FIG. 8 is a cross-sectional view of a conventional interposer.
The interposer 201 shown in FIG. 8 interconnects the contacted objects, for example, the conductive pads 231 of the circuit board 230 and the semiconductor bumps 240, and has a conductive contact 210 and an insulation that supports the contacts 210. The housing 220 is provided with a sex.

The contact 210 includes a spring portion 211 and a pair of contact points 212 and 213. The contact 210 is made of, for example, a Ni alloy such as Ni—Co or NiMn, and is manufactured by a fine processing technique that combines photolithography and electroforming.
Here, the spring portion 211 of the contact 210 has a substantially bowl shape formed in an endless loop shape that is elastically deformed by being pressed.

  Further, the pair of contacts 212 and 213 of the contact 210 are formed so as to protrude outward at the upper and lower positions separated from each other by a substantially half circumference of the loop of the spring portion 211. The tip portions of the pair of contacts 212 and 213 can be formed in an arc shape with a radius of 30 μm or less by a microfabrication technique combining photolithography and electrocasting, for example, 5 μm. Yes. The pair of contact points 212 and 213 are pressed by contacting each contacted object facing each other, for example, the semiconductor bump 240 and the conductor pattern 231.

  According to this contact 210, the respective tip portions of the pair of contacts 212 and 213 are formed in an arc shape having a radius of 30 μm or less by a fine processing technique combining photolithography and electroforming. For this reason, when the pair of contact points 212 and 213 come into contact with the respective objects to be contacted and are pressed, a high concentrated stress can be obtained even with a low load, that is, a low contact pressure. Therefore, even if contamination or an insulating film is formed on the surface of the contacted object, the pair of contacts 212 and 213 breaks down due to the high concentrated stress, and a good contact resistance with the contacted object is obtained. Can do.

Japanese Patent Laid-Open No. 2005-78865 JP 2009-158387 A

However, the conventional contact 120 used in the IC socket 101 shown in FIG. 7 and the contact 210 used in the interposer 201 shown in FIG. 8 have the following problems.
That is, in the case of the contact 120 used in the IC socket 101 shown in FIG. 7, Patent Document 1 does not describe what size is appropriate for the radius of the tip end portion of the protrusion 123b.

Further, in the case of the contact 210 used in the interposer 201 shown in FIG. 8, in Patent Document 2, each tip portion of the pair of contacts 212 and 213 has a radius of 30 μm by a microfabrication technique combining photolithography and electroforming. It can be formed in the following arc shape, and the radius is 5 μm as an example.
However, Patent Document 2 does not disclose an optimum range of the radius of each of the pair of contact points 212 and 213 having a radius of 30 μm or less.

  Therefore, the present invention has been made in view of the above-mentioned problems, and its object is to clearly define the optimum range of the radius at the tip of the ridge constituting the contact point, whereby 0.098 N to 0.00. An object of the present invention is to provide an electrical contact that can obtain a high concentrated stress even at a low load of about 147 N, that is, a low contact pressure, has a low contact resistance value at a contact point with a contacted object, and has a small variation.

  In order to achieve the above object, an electrical contact according to claim 1 of the present invention is an electrical contact having a contact portion that contacts a contacted object having conductivity, and the contact of the contact portion with the contacted object. The surface is provided with at least one pair of ridges that protrude from the contact surface and constitute a contact point with the contacted object, and the radius of each tip of the ridges is 5 to 15 μm. Yes.

An electrical contact according to claim 2 of the present invention is the electrical contact according to claim 1, wherein the contact surface of the contact portion forms a curved surface, and a plurality of pairs of the protrusions are provided on the curved surface. It is characterized by having.
Furthermore, the electrical contact according to claim 3 of the present invention is characterized in that, in the electrical contact according to claim 1 or 2, a groove recessed from the contact surface is provided between the pair of protrusions.

  According to the electrical contact according to the present invention, the optimum range is clearly defined by setting the radius of the tip of each ridge constituting the contact to 5 to 15 μm. As a result, a high concentrated stress can be obtained even with a low load of about 0.098N to 0.147N, that is, a low contact pressure, and an electrical contact with a low contact resistance value at a contact point with a contacted object and a small variation can be obtained. Can be provided.

1 is a partial side view of an embodiment of an electrical contact according to the present invention. 1A and 1B show a main part of an electrical contact in FIG. 1, in which FIG. 1A is a partial side view in which the main part is enlarged, and FIG. It is a partial side view which shows the state which the other party board | substrate contacted with the electrical contact of FIG. 1 in the parallel state. It is a partial side view which shows the state which contacted the electrical contact of FIG. 1 in the state which shifted | deviated from the parallel state to the other substrate. It is a figure for demonstrating the test conditions for investigating the relationship between the resistance value in a contact, and the radius of the front-end | tip part of the protruding item | line which comprises a contact. It is a graph which shows the relationship between the resistance value in a contact, and the radius of the front-end | tip part of the protruding item | line which comprises a contact. FIG. 2A shows a conventional IC socket, in which FIG. 1A is a partial cross-sectional view showing a state where an IC package lead and an IC socket contact are connected, and FIG. It is sectional drawing of the conventional interposer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
An electrical contact 1 shown in FIG. 1 is an electrical contact used for an electrical connector such as a DDR socket connector, and extends from a fixed portion (not shown) fixed to an insulating housing (not shown) of the electrical connector. An elastic arm portion 2 is provided. As shown in FIG. 3, a contact portion 3 that contacts the conductive pattern (contacted object) of the mating substrate 10 is provided at the tip of the elastic arm portion 2. As shown in FIGS. 1 and 2A, the contact portion 3 is formed to be curved so that the upper side is convex from the tip of the elastic arm portion 2, and the contact surface 4 with the conductor pattern of the mating substrate 10 is also formed. The upper side is a convex curved surface. On the other hand, a connecting portion (not shown) for connecting the contact 1 on the circuit board is provided on the side of the fixed portion opposite to the side on which the elastic arm portion 2 extends. The electrical contact 1 is formed by dragging, stamping (punching) and forming (bending) described later on a metal plate.

  As shown in FIGS. 1 and 2 (A), a plurality of pairs (this embodiment) projecting upward from the contact surface 4 and forming contact points with the conductor pattern of the mating substrate 10 are formed on the contact surface 4 of the contact portion 3. In the form, three pairs) of ridges 5a are provided. Even if the conductor pattern of the mating substrate 10 is in contact with the contact surface 4 of the contact part 3, as shown in FIG. 3, it actually contacts the tip of the ridge 5a constituting the contact. As shown in FIGS. 1 and 2A, a substantially V-shaped groove 5b that is recessed from the contact surface 4 is formed between each pair of ridges 5a. Each groove 5b extends in a direction (direction perpendicular to the paper surface in FIG. 2A) perpendicular to the wiping direction (arrow W direction in FIG. 2A). The protruding ridges 5a forming a pair extend along the groove 5b on both sides of the groove 5b.

  Here, each of these pairs of ridges 5a and grooves 5b is formed by dragging. That is, each of these pairs of ridges 5a and grooves 5b has a rectangular cross section in a direction perpendicular to the wiping direction (arrow W direction in FIG. 2A) (direction perpendicular to the paper surface in FIG. 2A). It is formed by scratching the contact surface 4 by mechanical means such as a jig. The material of the plate material shaved by dragging rises on both sides of the groove 5b without being separated from the material, and is effectively used to form the ridge 5a. This dragging is performed before stamping the metal plate.

And, as the dimensions of these ridges 5a and grooves 5b, the distance d between the pair of ridges 5a is 100 μm, the height h of the ridges 5a is 35 μm, the width w at the deepest part of the grooves 5b is 15 μm, the ridges It is preferable that the depth D from the tip of 5a to the deepest part of the groove 5b is 70 μm, and the distance P between adjacent ridges 5a is 100 μm.
In particular, the groove 5b is deepened by increasing the depth D from the tip of the ridge 5a to the deepest part of the groove 5b so as to approach the plate thickness of the electrical contact 1. Thereby, when the foreign material scraped off at the time of wiping is accommodated in the groove | channel 5b, the accommodation amount of the foreign material can be increased, and the cleaning effect can be improved further.

  Moreover, the radius R of the front-end | tip part of each protruding item | line 5a shown to FIG. 2 (B) shall be 5-15 micrometers. If the radius R of the tip is less than 5 μm, the ridge 5a having the tip having a radius R of less than 5 μm cannot be created by dragging. Further, when the radius R is less than 5 μm, when the object to be contacted contacts the tip of the ridge 5a, the tip of the ridge 5a may pierce the object to be contacted, and the elastic arm 2 may be plastically deformed. is there. On the other hand, if the radius R of the tip portion is larger than 15 μm, high concentrated stress (Hearts stress) cannot be obtained at a low load of about 0.098N to 0.147N, that is, a low contact pressure, and the conductor of the mating substrate 10 The contact resistance value at the contact point with the pattern (contacted object) cannot be lowered, and the contact resistance value varies greatly. Accordingly, the radius R of the tip of each ridge 5a is 5 to 15 μm.

In order to verify the grounds for setting the radius R of the tip of each protrusion 5a to 5 to 15 μm, the inventors have determined the resistance value of the protrusion 5a constituting the contact and the tip of the protrusion 5a constituting the contact. The test for investigating the relationship with the radius R was conducted.
In this test, as shown in FIG. 5, a contact portion 3 made of phosphor bronze having a pair of ridges 5a formed by dragging was used. For the radius R of the tip of the ridge 5a, three 5 μm samples (N1, N2, N3), three 15 μm samples (N1, N2, N3), and three 25 μm samples (N1, N1, N2, N3) N2, N3), three 50 μm samples (N1, N2, N3) and three 200 μm samples (N1, N2, N3) were prepared.

And the elastic arm part 2 was fixed about each sample, and the thing which gave the gold plating to the contact part of the copper plate as the metal plate M was made to contact with respect to the protruding item | line 5a as shown in FIG. At this time, the load F of the metal plate M on the ridges 5a was 0.098N.
At this time, the resistance value between the protrusion 5a constituting the contact point in each sample and the metal plate M was measured. The results are shown in Table 1 and FIG.

  Referring to Table 1 and FIG. 6, the resistance values of samples N1, N2, and N3 having a radius R of 5 μm at the tip of the ridge 5a are 40, 50, and 45 mΩ, and samples N1, N2, and R2 having a radius R of 15 μm, The resistance value of N3 was 50, 60, and 55 mΩ. Therefore, for the sample having the same radius R of 5 μm, the average resistance value is 45 mΩ, the difference between the maximum and minimum resistance values is 10 mΩ, and the contact resistance value at the contact point with the metal plate (contacted object) M is low. And it was found that the variation was small. Moreover, the average value of the resistance value of the sample having the same radius R of 15 μm is 55 mΩ, the difference between the maximum value and the minimum value is 10 mΩ, the contact resistance value at the contact point with the metal plate M is low, and the variation is small. It turned out to be a thing. Therefore, from this result, it can be said that those having the same radius R of 5 μm to 15 μm are stable regions where the contact resistance value at the contact point with the metal plate M is low and variation is small.

  On the other hand, the resistance values of the samples N1, N2, and N3 having a radius R of 25 μm at the tip of the ridge 5a are 210, 325, and 140 mΩ, and the resistance values of the samples N1, N2, and N3 having the radius R of 50 μm are 435, The resistance values of Samples N1, N2, and N3 having 500 and 325 mΩ and the same radius R of 200 μm were 625, 750, and 450 mΩ. Therefore, the average value of the resistance value for the sample having the same radius R of 25 μm is 225 mΩ, the difference between the maximum value and the minimum value is 185 mΩ, the contact resistance value at the contact point with the metal plate M is high, and the variation is It turned out to be a big one. In addition, for the sample having the same radius R of 50 μm, the average resistance value is 420 mΩ, the difference between the maximum and minimum resistance values is 175 mΩ, the contact resistance value at the contact point with the metal plate M is high, and the variation is large. It turned out to be a thing. Furthermore, for the sample having the same radius R of 200 μm, the average resistance value is 608 mΩ, the difference between the maximum and minimum resistance values is 300 mΩ, the contact resistance value at the contact point with the metal plate M is high, and the variation is large. It turned out to be a thing. Therefore, from this result, it can be said that those having the same radius R exceeding 15 μm are unstable regions where the contact resistance value at the contact point with the metal plate M is high and variation is large.

Therefore, the inventors set the radius R of the tip portion of each protrusion 5a to 15 μm or less in order to obtain a stable region where the contact resistance value at the contact point with the contacted object is low and variation is small.
FIGS. 3 and 4 show a state in which the conductor pattern of the mating substrate 10 contacts the electrical contact 1 configured as described above.
As shown in FIG. 3, the mating substrate 10 is in parallel contact with the ridges 5 a forming a central pair among the three pairs of ridges 5 a of the electrical contact 1. Then, the conductor pattern of the mating substrate 10 comes into contact with the central ridge 5a among the three pairs of ridges 5a. As a result, the conductor pattern of the mating substrate 10 and the electrical contact 1 are electrically connected. In addition, when the mating substrate 10 contacts the ridge 5a of the electrical contact 1 with a slight angular deviation from the parallel state, the conductor pattern of the mating substrate 10 is the center of the three pairs of ridges 5a. It contacts one of the protruding ridges 5a.

  At this time, the ridge 5a is wiped in the W direction in FIGS. 3 and 2B. Then, the foreign material scraped off at the time of wiping is accommodated in the groove 5b. In the present embodiment, since the groove 5b that is recessed from the contact surface 4 is provided between the pair of ridges 5a, the foreign matter scraped off during wiping can be accommodated in the groove 5b, and the cleaning effect can be improved. it can. Then, as described above, the groove 5b is deepened by increasing the depth D from the tip of the ridge 5a to the deepest part of the groove 5b to be close to the plate thickness of the electrical contact 1. Thereby, the amount of foreign matter can be increased, and the cleaning effect can be further enhanced.

  On the other hand, as shown in FIG. 4, when the counter substrate 10 is largely deviated from the parallel state with respect to the central ridge 5 a of the three ridges 5 a of the electrical contact 1, The conductor pattern of the board | substrate 10 contacts one or both of the protruding item | line 5a which makes the pair adjacent to the protruding item | line 5a which makes | forms the center pair among the three pairs of protruding item | lines 5a. This is possible because the contact surface 4 of the contact portion 3 forms a curved surface, and a plurality of pairs (three pairs in the case of the present embodiment) of protrusions are provided on the curved surface. At this time, since there is one or two ridges 5a with which the conductor pattern of the mating substrate 10 comes into contact, it is high even if the conductor pattern of the mating substrate 10 contacts with a low load of about 0.098N to 0.147N. Concentrated stress can be secured.

  On the other hand, when the contact surface 4 of the contact portion 3 is formed in a flat plane shape that is not curved, and a plurality of pairs of protrusions 5a are provided on the plane, the conductor pattern of the mating substrate 10 has a plurality of pairs of protrusions. All of the articles 5a will be contacted. This is because the surface on which the conductor pattern of the counterpart substrate 10 is formed is usually a flat surface that is not curved. In this case, when the conductor pattern of the mating substrate 10 is contacted with a low load of about 0.098N to 0.147N, the stress is distributed to all the ridges 5a, and a high concentrated stress cannot be secured in each ridge 5a. .

Therefore, in the present embodiment, the contact surface 4 of the contact portion 3 is configured by a curved surface, and a plurality of pairs of ridges 5a are provided on the curved surface.
As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.
For example, the electrical contact 1 only needs to have at least one pair of protrusions 5a on the contact surface 4 of the contact portion 3, and may not have a fixing portion to the housing or a connection portion to the circuit board.

In the electrical contact 1, it is not always necessary to provide a plurality of pairs of protrusions 5 a, and at least one pair may be provided. For example, as shown in FIG. 5, one pair of ridges 5 a may be provided, or two pairs, four pairs or more may be provided although not shown.
Further, the contact surface 4 of the contact portion 3 does not necessarily have to be a curved surface, and the groove 5b does not necessarily have to be provided between the pair of convex strips 5a.
In addition, the conductor pattern of the mating substrate 10 is in contact with the contacted object, but a metal contact or semiconductor bump may be used as long as it is a contacted object having conductivity.

DESCRIPTION OF SYMBOLS 1 Electrical contact 3 Contact part 4 Contact surface 5a Projection 5b Groove 10 Counter board

Claims (3)

In an electrical contact having a contact portion that contacts a contacted object having conductivity,
The contact surface of the contact portion with the object to be contacted is provided with at least one pair of protrusions that protrude from the contact surface and constitute a contact point with the object to be contacted, and the radius of each tip of the protrusions is An electrical contact having a thickness of 5 to 15 μm.   The contact according to claim 1, wherein a contact surface of the contact portion constitutes a curved surface, and a plurality of pairs of the protrusions are provided on the curved surface.   The electrical contact according to claim 1, wherein a groove recessed from the contact surface is provided between the pair of protrusions.

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