JP2014137264A - Contact probe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact probe capable of attaining minimization of an outer diameter as much as possible without deteriorating contact performance with an electrode.SOLUTION: A contact probe is configured such that by a compression coil spring 4 incorporated in a sleeve 1 for storing a first plunger 2 so as to move forward and backward so that one end 2a is defined as a contact end 2a' to an inspection target object, the first plunger in which the contact end side is projected from an open end of the sleeve at a constant amount is kept in a state of being at an advance position. A metal wire constituting a spring is configured to have a flat cross-sectional shape long in a length direction x of the spring and short in a radial direction y of the spring.

Description

  In this measurement of an inspection object that requires measurement of electrical characteristics, such as an electronic component such as a semiconductor element, an electronic circuit, etc., an electrical signal obtained from the inspection object is transmitted to various measuring instruments. It is related with the improvement of the contact probe used in order to transmit.

  There are contact probes called rotary or turn type. In this type of contact probe, a helical guide surface is formed on a plunger by cutting, and a sleeve (also referred to as a barrel) in which a convex portion that contacts the spiral guide surface is accommodated. The contact end side of the plunger protrudes from the sleeve by a certain amount by the compression coil spring formed and further incorporated. Then, when the contact end of the plunger comes into contact with an inspection object such as a semiconductor element, typically the electrode comes into contact with the electrode, typically the plunger moves backward within the sleeve on the fixed side. Yes.

  Here, the pitch between electrodes of the semiconductor element or the like has been minimized with the miniaturization of the semiconductor element or the like, and accordingly, the outer diameter of the contact probe is also required to be minimized.

  In order to minimize the outer diameter of the contact probe, that is, the outer diameter of the sleeve, it is essential to minimize the outer diameter of the spring. That is, in order to make the outer diameter of the sleeve 0.1 mm, the outer diameter of the spring needs to be less than 0.08 mm.

  On the other hand, in the process of making a metal wire into a coil shape and making the spring, the limit is that the outer diameter of the spring is four times the wire diameter of the metal wire in relation to the outer diameter of the spring and the wire diameter of the metal wire. is there. For this reason, for example, when the outer diameter of the spring is 0.07 mm, the diameter of the metal wire constituting the spring cannot generally be 0.018 mm or more.

  However, since the spring constant is proportional to the fourth power of the diameter of the metal wire constituting the spring, it is required to make the outer diameter of the spring as small as possible while making the diameter of the metal wire as large as possible. It is where it is done.

  That is, the wire diameter of the metal wire constituting the spring affects the pressing load of the contact end of the plunger against the electrode, that is, the contact performance of the contact probe with the electrode.

JP-A-9-281141

  The main problem to be solved by the present invention is that the outer diameter of the contact probe can be minimized as much as possible without deteriorating the contact performance with the electrode in the contact probe.

In order to achieve the above object, according to the present invention, the contact probe is opened by a compression coil spring built in a sleeve in which a plunger having one end as a contact end with respect to an object to be inspected can be moved back and forth. A contact probe configured to maintain a state in which the plunger projecting a predetermined amount from the end to the contact end side is in an advanced position;
The metal wire constituting the spring is configured to have a flat cross-sectional shape that is long in the length direction of the spring and short in the radial direction of the spring.

  In the contact probe according to the present invention, the metal wire constituting the spring constituting the contact probe is configured to have a flat cross-sectional shape that is long in the length direction of the spring and short in the radial direction of the spring. Therefore, while minimizing the outer diameter of the spring as much as possible, the cross-sectional area of the metal wire is maximized as much as possible, and the outer diameter of the contact probe is reduced without deteriorating the contact performance with the electrode. Minimization as much as possible can be realized.

FIG. 1 is a cross-sectional view showing a sleeve body constituting a contact probe according to an embodiment of the present invention as a cross section along its length direction. FIG. 2 is a cross-sectional view of a metal wire constituting a spring constituting the contact probe.

  Hereinafter, a typical embodiment of the present invention will be described with reference to FIGS. 1 and 2. The contact probe according to this embodiment is used for measuring various kinds of measuring objects such as electronic components such as semiconductor elements and electronic circuits that require measurement of electrical characteristics. It is used to transmit an electrical signal obtained from. Such a contact probe includes a sleeve, a plunger, and a compression coil spring.

  In the illustrated example, there are two plungers. That is, in the illustrated example, the contact probe is configured by combining a sleeve 1, a first plunger 2, a second plunger 3, and a compression coil spring 4 each made of a conductive material.

  The sleeve 1 has an elongated cylindrical shape with both ends open.

  Each of the first plunger 2 and the second plunger 3 has a rod shape whose outer diameter is slightly smaller than the inner diameter of the sleeve 1. The first plunger 2 is inserted into the sleeve 1 with its one end 2a as a contact end 2a ′ protruding outward from one open end of the sleeve 1 and the other end 2b side first. 1 is combined with the sleeve 1 so as to be movable back and forth along the direction of the cylinder axis. The second plunger 3 is inserted into the sleeve 1 with its one end 3a protruding outward from the other open end of the sleeve 1 and the other end 3b side first. Like the first plunger 2, the sleeve 1 is combined with the sleeve 1 so as to be movable back and forth along the cylinder axis direction.

  The sleeve 1 is compressed between the other end 2b of the first plunger 2 and the other end 3b of the second plunger 3 in a direction along the length of the spring in the cylinder axis direction of the sleeve 1. A coil spring 4 is accommodated. One end of the spring 4 serves as a contact portion 4 a to the other end 2 a of the first plunger 2, and the other end serves as a contact portion 4 b to the other end 3 b of the second plunger 3.

The first plunger 2 has a spiral guide surface 2c between both ends 2a, 2b. The spiral guide surface 2c is formed by cutting a base material of the first plunger 2 having a round bar shape, and the cross section of the first plunger 2 is formed at a location where the spiral guide surface 2c is formed. D-shaped. The spiral guide surface 2 c is formed along a virtual spiral that goes around the axis of the first plunger 2. A step 2 d is formed between the spiral guide surface 2 c and the other end 2 b of the first plunger 2. On the other hand, the second plunger 3 has a small diameter portion 3c between both ends 3a, 3b.
In this embodiment, the sleeve 1 protrudes inwardly, and includes a front convex portion 1a that slides on the spiral guide surface 2c of the first plunger 2, and a second plunger. 3 is formed between the both ends of the rear projection 1b. The front and rear protrusions 1a and 1b hold the first plunger 2 and the second plunger 3 at their forward positions protruding from the sleeve 1 by a certain amount.

  From the state in which the sleeve 1 side is fixed to the contact probe mounting member (not shown), the contact end 2a ′ of the first plunger 2 is placed at the contacted location (not shown) of the object to be inspected. , The first plunger 2 is rotated and retracted while compressing the spring 4 by the cooperation of the spiral guide surface 2c and the front convex portion 1a, and deposits (oxidation) are formed on the surface of the contacted portion. Even when there is a coating, flux, etc., the contact end is appropriately electrically connected to the contacted portion except for this. In the illustrated example, the contact end 3a 'of the second plunger 3 is brought into contact with the electrode on the measuring instrument side with a predetermined load, whereby the inspection object and the measuring instrument side are contact probes. It is designed to be electrically connected via

  In the contact probe according to this embodiment, the metal wire 4 ′ constituting the spring 4 has a flat cross-sectional shape that is long in the length direction x of the spring 4 and short in the radial direction y of the spring 4. It is configured to have. The metal wire 4 ′ having such a cross section is typically a metal wire having a circular cross section (the outer diameter is indicated by an imaginary line in FIG. 2) by rolling, and the metal wire 4 ′ It can be obtained by making the cross section in the direction perpendicular to the length direction into an oval shape. Then, coil processing is performed on the metal wire 4 ′ having an oval cross section in this manner so as to form a coil shape in a direction along the length direction x of the spring 4 to be generated. Thus, the spring 4 can be obtained. The spring 4 composed of the metal wire 4 'is in sliding contact with the inner surface of the sleeve 1 when the first plunger 2 and the second plunger 3 are moved, but the metal wire 4' has an oval cross section. Therefore, such sliding contact resistance is minimized.

  Thereby, the cross-sectional area of the metal wire 4 ′ can be maximized as much as possible while minimizing the outer diameter of the spring 4 as much as possible. For example, when the spring 4 having an outer diameter of 0.07 mm is formed of a metal wire having a circular cross section, the process of making the metal wire into a coil shape and forming the spring 4 includes the outer diameter of the spring 4 and the wire diameter of the metal wire. In this relation, since the limit of the outer diameter of the spring 4 is four times the diameter of the metal wire, the diameter of the metal wire is 0.018 mm at the maximum. However, according to the metal wire 4 ′ having an elliptical cross section as described above, the size of the metal wire 4 ′ in the radial direction y of the generated spring 4 is 0.018 mm that can be processed by the coil. The dimension of the metal wire in the length direction x of the spring 4 can be made larger than 0.018 mm. Since the spring constant is proportional to the fourth power of the diameter of the metal wire constituting the spring, the spring 4 composed of the metal wire 4 ′ having an elliptical cross section as described above has a circular cross section. The spring constant is made larger than that of the spring 4 made of a metal wire having the same outer diameter as that of the spring made of a metal wire and having a circular cross section. Since the outer diameter of the contact probe, that is, the outer diameter of the sleeve 1 depends on the outer diameter of the spring 4, according to this embodiment, the contact performance of the contact probe due to the biasing force of the spring 4 is reduced. Without minimizing the outer diameter of the contact probe, it is possible to achieve as much as possible. Further, according to the spring 4 configured as described above, it is possible to shorten the overall length as much as possible while ensuring a predetermined biasing force. Can be minimized as much as possible and contribute to high-speed transmission of electrical signals.

1 Sleeve 2 First Plunger 2a One end 2a 'Contact end 4 Spring 4' Metal wire x Spring length direction y Spring radial direction

Claims (1)

The plunger with a fixed end protruding from the open end of the sleeve to the forward position by a compression coil spring built in the sleeve, which has a plunger with one end in contact with the object to be inspected so as to move back and forth. A contact probe configured to maintain a certain state,
A contact probe characterized in that the metal wire constituting the spring has a flat cross-sectional shape that is long in the length direction of the spring and short in the radial direction of the spring.

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