Inspection Socket

Abstract

To provide an inspection socket capable of stabilizing a contact between a terminal and an electrode by correcting a tilt of the terminal to be in contact with an inspection device.SOLUTION: An inspection socket comprises: contact terminals 100A each including a barrel 110 in which a flange 114 is provided, a device side terminal 120, a test substrate side terminal 130 and a spring; a housing 200 including stepped holes 210 in each of which a contact terminal 100 is inserted and a step 211 abutted to the flange 114 is formed in a direction of an axis X; and a movable pedestal 300 which is provided so as to approach to and separate from the housing 200 and includes housing holes 310 in which the side of a tip end 121 of the device side terminal 120 protruding from the barrel 110 is inserted and an electrode 31 of an inspection device 30 is housed. A guide 311 having an inner diameter substantially equal to an outer diameter of the portion of the device side terminal 120 protruding from the barrel 110 is formed in the housing hole 310 of the movable pedestal 300.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an inspection socket. [Background technology]

[0002] Electronic devices such as IC packages mounted on electronic devices are generally tested using inspection sockets to remove potential defects before being mounted on a wiring board. The inspection sockets are attached to a test board or a printed wiring board used as a mounting board.

[0003] As an example of such a socket, a socket with a movable base is disclosed in Patent Document 1. The socket with a movable base disclosed in Patent Document 1 is configured so that solder balls of the package come into contact with terminals of the probes through through holes formed in the movable base (fourth base). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-326048 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration of Patent Document 1, there is a possibility that the terminal of the probe may tilt within the through hole formed in the fourth base, which may result in poor contact with the solder ball or damage to the terminal.

[0006] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an inspection socket that can correct the inclination of the terminals that contact an inspection device, thereby stabilizing the contact between the terminals and the electrodes. [Means for solving the problem]

[0007] In order to solve the above problems, the inspection socket of the present invention employs the following measures. That is, an inspection socket according to one aspect of the present invention comprises: a barrel consisting of a cylindrical body extending along an axial direction and having a flange portion provided on an outer circumferential surface of the cylindrical body that protrudes in a radial direction; contact terminals having: a device-side terminal whose base end is accommodated in one end side of the barrel and whose tip end contacts a testing device; a test board-side terminal whose base end is accommodated in the other end side of the barrel and whose tip end contacts a test board; and a spring that contacts the test board-side terminal and the device-side terminal within the barrel; a housing having a stepped hole through which the contact terminal is inserted along the axial direction and which has a step formed therein that abuts against the flange portion in the axial direction; and a movable base which is provided so as to be movable toward and away from the housing, has an accommodation hole through which a tip side of the device-side terminal protruding from the barrel is inserted and which accommodates an electrode of the inspection device, and the accommodation hole of the movable base has a diameter approximately equal to an outer diameter of a portion of the device-side terminal protruding from the barrel. and is independent of the size of the electrodes of the testing device. A guide portion is formed having an inner diameter.

[0008] According to the present embodiment, the inspection socket includes a so-called double-movable contact terminal having a barrel with a flange portion, a device-side terminal, a test board-side terminal, and a spring, a housing having a stepped hole in which the contact terminal is inserted and in which a step is formed that abuts against the flange portion in the axial direction, and a movable base that is provided so as to be movable toward and away from the housing and has a housing hole in which the tip side of the device-side terminal protruding from the barrel is inserted and in which an electrode of the inspection device is housed. Therefore, the barrel together with the flange portion can be pressed down by the stepped hole formed in the housing to apply a preload to the test board. At this time, since the position of the stepped portion of the stepped hole does not depend on the length dimension of the barrel, the thickness dimension (dimension along the axial direction) of the housing at the portion that presses down the flange portion can be increased by arbitrarily adjusting the position of the stepped portion. This makes it possible to suppress deformation of the housing due to the reaction force of the preload. In addition, since the position of the stepped portion of the stepped hole corresponds to the position of the flange portion and does not depend on the length dimension of the barrel, the housing can be made thinner and the movable base thicker accordingly. This makes it possible to ensure a thickness dimension of the movable base sufficient to form the following guide portion. Here, the housing hole of the movable base is formed with a guide portion having an inner diameter that is approximately the same as the outer diameter of the portion of the device-side terminal protruding from the barrel, so that the inclination of the device-side terminal can be corrected, thereby stabilizing the contact between the device-side terminal and the electrode (e.g., solder ball) in the housing hole.

[0009] In addition, in the inspection socket according to one aspect of the present invention, the accommodating hole of the movable base is formed with a countersunk portion for accommodating the barrel protruding from the housing.

[0010] According to the inspection socket of the present embodiment, the accommodating hole of the movable base is formed with a countersunk portion in which the barrel protruding from the housing is accommodated, thereby avoiding interference between the barrel and the movable base that may occur when the movable base approaches the housing.

[0011] In the inspection socket according to one aspect of the present invention, the countersunk portion is formed integrally and continuously with the other adjacent countersunk portions.

[0012] According to the inspection socket of this aspect, since the countersunk portions are formed integrally and continuously with the other adjacent countersunk portions, it is possible to form a plurality of countersunk portions at once, which makes it possible to form the countersunk portions efficiently.

[0013] In an inspection socket according to one aspect of the present invention, the movable base is divided in the axial direction.

[0014] According to the inspection socket of the present embodiment, the movable base is divided in the axial direction, so that without processing, such as drilling holes from both sides of a single component that constitutes a single movable base, it is possible, for example, to combine the back sides of two components that have been processed from the front side to form a single movable base.

[0015] In the inspection socket according to one aspect of the present invention, the device-side terminal is provided at its tip with an expanded diameter terminal portion having substantially the same diameter as the barrel.

[0016] According to the inspection socket of this aspect, the device-side terminal is provided with an expanded terminal portion at its tip, which has approximately the same diameter as the barrel, and therefore can serve as both the guide portion and the countersunk portion formed in the receiving hole. During inspection, the contact terminal has an approximately constant diameter overall, which can eliminate impedance mismatch.

[0017] In the testing socket according to one aspect of the present invention, the device-side terminals and the test-board-side terminals are provided at their tips with enlarged-diameter terminal portions having substantially the same diameter as the barrel.

[0018] According to the inspection socket of this aspect, the device-side terminal is provided with an expanded terminal portion at its tip, which has approximately the same diameter as the barrel, and therefore can serve as both the guide portion and the countersunk portion formed in the receiving hole. During inspection, the contact terminal has an approximately constant diameter overall, which can eliminate impedance mismatch. Furthermore, since the test board side terminal is also provided with an expanded diameter terminal portion at its tip, the diameter of which is approximately the same as that of the barrel, impedance mismatch can be eliminated during testing.

[0019] In the inspection socket according to one aspect of the present invention, the device-side terminal is set to a length dimension such that the enlarged terminal portion contacts the one end of the barrel during inspection.

[0020] According to the inspection socket of this embodiment, the device-side terminal is set to a length dimension such that the expanded terminal portion abuts against one end of the barrel during inspection, so that the expanded terminal portion stably contacts the end of the barrel during inspection. This makes it possible to stabilize the contact resistance between the device-side terminal and the barrel. Even if the barrel is further pressed in after the expanded terminal portion abuts against the end of the barrel, the contact terminal is of a so-called bi-directional movable type, so that the displacement caused by the pressing can be absorbed by the test board-side terminal. In addition, with this configuration, the entire portion of the device-side terminal other than the enlarged terminal portion is housed in the barrel (visibly hidden) during testing, so that the contact terminal has a substantially constant diameter as a whole during testing, and impedance mismatches can be further eliminated. Effect of the Invention

[0021] According to the present invention, the inclination of the terminals that come into contact with the testing device can be corrected to stabilize the contact between the terminals and the electrodes. [Brief description of the drawings]

[0022] [Figure 1] 1A and 1B are a front view and a longitudinal sectional view of an inspection socket according to a first embodiment; [Diagram 2] FIG. 2 is a front view of the contact probe according to the first embodiment. [Diagram 3] 1 is a longitudinal sectional view of a contact probe according to a first embodiment. FIG. [Figure 4] FIG. 2 is a plan view of the contact probe according to the first embodiment. [Diagram 5] FIG. 2 is a plan view of the contact probe according to the first embodiment. [Figure 6] 2 is a partial enlarged view of part A shown in FIG. 1, illustrating a state before the socket is mounted on the printed wiring board. FIG. [Figure 7] 2 is a partial enlarged view of part A shown in FIG. 1, illustrating a state in which a socket has been mounted on a printed wiring board and an IC package has not yet been placed on a movable base. [Figure 8] 2 is a partial enlarged view of part A shown in FIG. 1, illustrating a state in which a socket is mounted on a printed wiring board and an IC package is placed on a movable base. FIG. [Figure 9] 2 is a partial enlarged view of part A shown in FIG. 1, illustrating a state in which a socket is mounted on a printed wiring board and an IC package is attached to a movable base. FIG. [Figure 10] FIG. 4 is a bottom view of the movable base showing the countersunk portion according to the first embodiment. [Figure 11] FIG. 13 is a bottom view of the movable base showing another countersunk portion. [Figure 12] FIG. 13 is a bottom view of the movable base showing another countersunk portion. [Figure 13] FIG. 2 is a partial enlarged view of the A portion shown in FIG. 1 according to the first modified example, showing a state in which a socket has been mounted on a printed wiring board and an IC package has not yet been placed on a movable base. [Figure 14] FIG. 11 is a longitudinal sectional view of a contact probe according to a second embodiment. [Figure 15] 1, showing a state in which a socket is mounted on a printed wiring board and an IC package is attached to a movable base. FIG. [Figure 16]FIG. 11 is a vertical cross-sectional view of a contact probe according to a second modified example. [Figure 17] FIG. 2 is a partially enlarged view of a second modified example of the portion A shown in FIG. 1, illustrating a state in which a socket is mounted on a printed wiring board and an IC package is attached to a movable base. [Figure 18] 1, showing a state in which a socket is mounted on a printed wiring board and an IC package is attached to a movable base. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] [First embodiment] An inspection socket according to a first embodiment of the present invention will be described below with reference to the drawings.

[0024] [Socket Overview] FIG. 1 shows a front view and a vertical cross-sectional view of an inspection socket 10 (hereinafter simply referred to as "socket 10"). The socket 10 is a component that provides electrical continuity between the printed wiring board 20 and the IC package 30 during testing of the IC package 30. The socket 10 is mounted, for example, on the upper surface of the printed wiring board 20 serving as a test board. In addition, in a recess 320 of the socket 10 mounted on the printed wiring board 20, for example, the IC package 30 serving as a test device is attached. The IC package 30 may be of a ball grid array (BGA) type, a land grid array (LGA) type, or a quad flat package (QFP) type.

[0025] The socket 10 includes a contact probe (contact terminal) 100A, a housing 200, and a movable base 300. In the socket 10, the housing 200 is disposed on the side of the printed wiring board 20, and the movable base 300 is disposed so as to be stacked on top of the housing 200.

[0026] A base spring 401 is interposed between the housing 200 and the movable base 300, and biases both members in a direction separating them from each other. This allows the movable base 300 to elastically move toward and away from the housing 200. In detail, by removing the load, the movable base 300 moves away from the housing 200 , and by pressing the movable base 300 towards the housing 200 , the movable base 300 moves closer to the housing 200 .

[0027] A large number of contact probes 100A are housed upright between the housing 200 and the movable base 300 thus constructed. This contact probe 100A establishes electrical continuity between the IC package 30 attached to the socket 10 and the printed wiring board 20 on which the socket 10 is mounted.

[0028] [Contact probe details] As shown in Figures 2 and 3, contact probe 100A is a so-called double-movable type probe that has a barrel 110, an upper plunger (device side terminal) 120, a lower plunger (test board side terminal) 130, and a spring 140. Contact probe 100A has a probe length of, for example, about 3 mm under no load.

[0029] The barrel 110 is a thin-walled cylindrical body extending in the direction of the axis X, and has a space formed therein for accommodating the base end 121 of the upper plunger 120, the base end 131 of the lower plunger 130, and the spring 140. An upper end (one end) 111 and a lower end (the other end) 112 of the barrel 110 are formed with a caulking that shrinks radially inward. It should be noted that the term "radial direction" used here refers to the direction relative to the X-axis.

[0030] 2 to 5, a flange portion 114 that protrudes radially outward from the outer circumferential surface of the cylindrical body is formed between the upper end 111 and the lower end 112 of the barrel 110. The position of the flange portion 114 corresponds to the position of a step portion 211 formed in a stepped hole 210, which will be described later.

[0031] The flange portion 114 may be formed over the entire circumferential range (360°) as shown in Fig. 4, or may be formed over only a portion of the circumferential range as shown in Fig. 5. In addition, since the flange portion 114 is a portion formed to abut against a step portion 211 formed in a stepped hole 210 described later, the flange portion 114 may have a shape other than that shown in Figs. 4 and 5 as long as this function is fulfilled. It should be noted that the "circumferential direction" referred to here is with respect to the axis X.

[0032] As shown in FIG. 3, the upper plunger 120 is a substantially cylindrical terminal having a base end 121 and a tip end 122 . The base end 121 side has a diameter substantially the same as the inner diameter of the barrel 110 (more precisely, a diameter slightly smaller), and is housed in the barrel 110. On the other hand, the tip end 122 side has a diameter smaller than the base end 121, and protrudes from the upper end 111 of the barrel 110 when no load is applied. The tip end 122 is a so-called crown cut, and comes into contact with the solder ball (electrode) 31 of the IC package 30.

[0033] In the upper plunger 120, the boundary (the part where the outer diameter changes) between the part on the base end 121 side and the part on the tip end 122 side abuts against a rivet at the upper end 111 of the barrel 110, thereby preventing the upper plunger 120, which moves forward and backward relative to the barrel 110, from falling off the barrel 110.

[0034] The lower plunger 130 is a generally cylindrical terminal having a base end 131 and a tip end 132 . The base end 131 side has a diameter substantially the same as the inner diameter of the barrel 110 (more precisely, a diameter slightly smaller), and is housed in the barrel 110. On the other hand, the tip 132 side has a diameter smaller than the base end 131, and protrudes from the lower end 112 of the barrel 110 when no load is applied. The tip 132 that comes into contact with the printed wiring board 20 has a rounded shape.

[0035] In the lower plunger 130, the boundary (the part where the outer diameter changes) between the part on the base end 131 side and the part on the tip 132 side abuts against a rivet at the lower end 112 of the barrel 110, thereby preventing the lower plunger 130, which moves forward and backward relative to the barrel 110, from falling off the barrel 110.

[0036] The spring 140 is housed inside the barrel 110 . The spring 140 is interposed between the base end 121 of the upper plunger 120 and the base end 131 of the lower plunger 130, and biases both members in a direction separating them from each other in the direction of the axis X. As a result, when no load is applied, the upper plunger 120 abuts against the rivet at the upper end 111 of the barrel 110, and the lower plunger 130 abuts against the rivet at the lower end 112 of the barrel 110. Furthermore, by pushing the upper plunger 120 and / or the lower plunger 130 in a direction in which they approach each other, a repulsive force caused by the elastic force of the spring 140 acts between the upper plunger 120 and the lower plunger 130.

[0037] [Housing Details] As shown in FIG. 6, the housing 200 is divided into two parts, an upper housing 201 and a lower housing 202, in the direction of the axis X, and a stepped hole 210 through which the contact probe 100A is inserted along the direction of the axis X is formed so as to extend continuously through both the upper housing 201 and the lower housing 202.

[0038] A stepped portion 211 is formed in a stepped hole 210 formed in the upper housing 201 . In the stepped hole 210 , the inner diameter of the portion of the stepped hole 210 above the step portion 211 is smaller than the inner diameter of the portion of the stepped hole 210 below the step portion 211 . In detail, the inner diameter of the stepped hole 210 above the step portion 211 is smaller than the outer diameter of the flange portion 114 formed on the barrel 110, and is larger than the outer diameter of the portion of the barrel 110 other than the flange portion 114. In contrast, the inner diameter of the stepped hole 210 below the step portion 211 is larger than the outer diameter of the flange portion 114 formed on the barrel 110. This allows the flange portion 114 to abut against the step portion 211 (see FIG. 7).

[0039] As shown in Fig. 7, the step 211 is a portion that presses the contact probe 100A (barrel 110) toward the printed wiring board 20 when a preload is applied. That is, a reaction force of the preload acts on the housing 200 (upper housing 201) above the step 211. Therefore, by appropriately ensuring the thickness dimension of the housing 200 above the step 211, warping (deformation) caused by the reaction force of the preload can be suppressed. In other words, the position of the step 211 (the position along the direction of the axis X, the position in the thickness direction) can be set so as to ensure the strength of the housing 200. Also, the thickness dimension of the housing 200 (upper housing 201) can be adjusted by the position of the step portion 211. Therefore, it is possible to make the housing 200 as thin as possible while still ensuring strength, and to make the movable base 300 thicker accordingly. This makes it possible to ensure that the movable base 300 has a thickness dimension sufficient for forming the guide portion 311 described below.

[0040] As shown in FIG. 6, a stepped hole 210 formed in the lower housing 202 has a reduced diameter portion 212 formed therein. The inner diameter of reduced diameter portion 212 is smaller than the outer diameter of barrel 110 and is substantially the same diameter (more precisely, slightly larger) as the portion of lower plunger 130 protruding from barrel 110. This prevents contact probe 100A from falling off stepped hole 210.

[0041] With the above configuration, housing 200 is configured to accommodate and hold contact probe 100A in stepped hole 210. The housing 200 may be divided into three or more parts.

[0042] [Details of the movable base] As shown in FIG. 1, the movable base 300 is formed with a recess 320 in which the IC package 30 is placed and attached. As shown in FIG. 6, the movable base 300 has an accommodating hole 310 formed in the recess 320 along the X-axis direction. The tip 122 side of the upper plunger 120 is inserted into the accommodation hole 310, and the solder balls 31 of the IC package 30 placed on the movable pedestal 300 are accommodated therein (see FIGS. 8 and 9).

[0043] As shown in FIG. 6, a receiving hole 310 formed in the movable base 300 has a guide portion 311 and a countersunk portion 312 formed therein.

[0044] The guide portion 311 is a portion formed between the upper and lower portions of the accommodation hole 310, and has an inner diameter that is approximately the same as (more precisely, slightly larger than) the thickest portion of the portion of the upper plunger 120 that protrudes from the barrel 110. This makes it possible to guide the portion of the upper plunger 120 that protrudes from the barrel 110. The inner diameter of the guide portion 311 does not depend on the size of the solder ball 31.

[0045] The countersunk portion 312 is a portion formed in the lower portion of the receiving hole 310, and serves as a portion for receiving the barrel 110 protruding from the upper housing 201 (see FIG. 9). 10, the countersunk portion 312 is formed in a circular shape on the bottom surface of the movable base 300. In this case, one countersunk portion 312 is formed for one receiving hole 310. The countersunk portions 312 do not necessarily have to be in a one-to-one relationship with the accommodating holes 310, and adjacent countersunk portions 312 may be formed integrally and continuously with each other. For example, as shown in Fig. 11, only one recess may be formed for each of the accommodating holes 310, or as shown in Fig. 12, long and narrow slits may be formed in multiple rows.

[0046] [About using sockets] The socket 10 configured as above is used as follows. That is, first, the socket 10 is mounted on the printed wiring board 20 as shown in Fig. 6 and Fig. 7. Before mounting (Fig. 6), the tip 132 of the lower plunger 130 protrudes from the lower housing 202 (the amount of protrusion is p1). A gap c1 is provided between the flange portion 114 and the step portion 211. The length dimension of the lower plunger 130, the position of the step portion 211, and the position of the flange portion 114 are set so that p1>c1.

[0047] Tip 132 of lower plunger 130, which protrudes from lower housing 202 before mounting (FIG. 6), comes into contact with printed wiring board 20 after mounting (FIG. 7). At the same time, contact probe 100A is lifted upward. When contact probe 100A is lifted by c1, the upper surface of flange portion 114 comes into contact with step portion 211. At this time, because p1>c1, when the bottom surface of lower housing 202 and the top surface of printed wiring board 20 come into contact with each other, lower plunger 130 is pushed into barrel 110 by p1-c1. Here, lower plunger 130 is biased by spring 140, which applies a preload to printed wiring board 20. In addition, the reaction force of the preload is suppressed by a portion (shown by thickness t1) above step portion 211 of upper housing 201.

[0048] 8, after the socket 10 is mounted on the printed wiring board 20, the IC package 30 is placed on the bottom surface of the recess 320 formed in the movable base 300. At this time, the solder balls 31 of the IC package 30 are accommodated in the accommodation holes 310 formed in the movable base 300. However, the solder balls 31 do not yet come into contact with the tip 122 of the upper plunger 120.

[0049] 9, the movable base 300 on which the IC package 30 is placed is pressed into the housing 200. At this time, the solder balls 31 come into contact with the tips 122 of the upper plunger 120, and further press the upper plunger 120 into the barrel 110. Here, the upper plunger 120 is biased by the spring 140, whereby the IC package 30 is mounted in the socket 10 with an appropriate contact force being applied to the solder balls 31.

[0050] When the movable base 300 is pressed into the housing 200, the upper plunger 120 is guided by the guide portion 311 formed in the receiving hole 310, so that any inclination with respect to the receiving hole 310 or the solder ball 31 is corrected.

[0051] As described above, after the socket 10 is mounted on the printed wiring board 20 and the IC package 30 is attached to the socket 10, the IC package 30 is inspected.

[0052] According to this embodiment, the following effects are obtained. The contact probe 100A is a so-called double-movable type contact probe having a barrel 110 provided with a flange portion 114, an upper plunger 120, a lower plunger 130, and a spring 140, a housing 200 having a stepped hole 210 into which the contact probe 100A is inserted and in which a step 211 is formed that abuts against the flange portion 114 in the direction of the axis X, and a movable base 300 which is provided so as to be movable toward or away from the housing 200, has an accommodating hole 310 into which the tip 122 side of the upper plunger 120 protruding from the barrel 110 is inserted and in which a solder ball 31 of the IC package 30 is accommodated. Therefore, a preload can be applied to the printed wiring board 20 by pressing down the barrel 110 together with the flange portion 114 through the stepped hole 210 formed in the housing 200. At this time, since the position of the step 211 of the stepped hole 210 does not depend on the length dimension of the barrel 110, the thickness dimension of the housing 200 at the portion that presses the flange portion 114 can be increased by arbitrarily adjusting the position of the step 211. This makes it possible to suppress deformation of the housing 200 due to the reaction force of the preload. In addition, since the position of the step 211 of the stepped hole 210 corresponds to the position of the flange portion 114 and does not depend on the length dimension of the barrel 110, it is also possible to make the housing 200 thinner and the movable base 300 thicker accordingly. This makes it possible to ensure a thickness dimension in the movable base 300 that is sufficient to form the guide portion 311.

[0053] Furthermore, since the accommodation hole 310 of the movable base 300 is formed with the guide portion 311 having an inner diameter substantially equal to the outer diameter of the portion of the upper plunger 120 protruding from the barrel 110, it is possible to correct the inclination of the upper plunger 120. This makes it possible to stabilize the contact between the upper plunger 120 and the solder ball 31 in the accommodation hole 310.

[0054] In addition, the accommodating hole 310 of the movable base 300 is formed with a countersunk portion 312 in which the barrel 110 protruding from the housing 200 is accommodated, thereby making it possible to avoid interference between the barrel 110 and the movable base 300 that may occur when the movable base 300 approaches the housing 200.

[0055] Moreover, the countersunk portions 312 may be formed integrally and continuously with other adjacent countersunk portions 312, and a plurality of the countersunk portions 312 can be formed at once. This allows the countersunk portions 312 to be formed efficiently.

[0056] [Variation 1] 13, the movable base 300 may be divided into two parts, an upper base 301 and a lower base 302, in the direction of the axis X. In this case, the accommodation hole 310 is formed so as to be continuous across both the upper base 301 and the lower base 302, and the guide portion 311 and the countersunk portion 312 are formed in the lower base 302.

[0057] According to this configuration, even without processing such as drilling holes from both sides of one component constituting one movable base 300, for example, it is possible to combine the back surfaces of upper base 301 and lower base 302 processed from the front surface to form one movable base 300. This makes it possible to improve the efficiency of processing.

[0058] [Second embodiment] An inspection socket according to a second embodiment of the present invention will now be described with reference to the drawings. The inspection socket according to this embodiment differs from the inspection socket according to the first embodiment in the shape of the upper plunger and the shape of the receiving hole, but the other configurations are the same. Therefore, the same components are denoted by the same reference numerals and the description thereof will be omitted.

[0059] As shown in FIG. 14, contact probe 100B is a so-called big head type probe, and an expanded diameter terminal portion 123 is provided at a tip 122 of an upper plunger 120.

[0060] The outer diameter of expanded terminal portion 123 is substantially the same as the outer diameter of the barrel 110 other than flange portion 114. This eliminates the need to make guide portion 311 and countersunk portion 312 formed in accommodating hole 310 have different diameters, as shown in Fig. 15, and allows guide portion 311 and countersunk portion 312 to be used together.

[0061] The upper plunger 120 provided with the expanded diameter terminal portion 123 is set to a length dimension such that the lower surface of the expanded diameter terminal portion 123 intentionally comes into contact with the upper end 111 of the barrel 110 when the upper plunger 120 is pushed into the barrel 110 by the solder ball 31 during testing. This makes it possible to prevent the upper plunger 120 from rattling relative to the barrel 110 and maintain a good contact state. In addition, the entire portion of the upper plunger 120 below the expanded diameter terminal portion 123 can be hidden within the barrel 110, eliminating impedance mismatch.

[0062] In the upper plunger 120 configured in this manner, a gap c2 is provided between the housing 200 and the lower surface side of the flange portion 114 formed on the barrel 110. This ensures a margin for pushing the barrel 110 further downward, and avoids mechanical constraint of the barrel 110.

[0063] According to this embodiment, the following effects are obtained. Upper plunger 120 is provided with an expanded diameter terminal portion 123 at its tip 122, which has approximately the same diameter as barrel 110, so that it can serve as both guide portion 311 and countersunk portion 312 formed in accommodating hole 310.

[0064] Furthermore, since the length of the upper plunger 120 is set so that the expanded diameter terminal portion 123 abuts against the upper end 111 of the barrel 110 during inspection, the expanded diameter terminal portion 123 stably contacts the upper end 111 of the barrel 110 during inspection. This makes it possible to stabilize the contact resistance between the upper plunger 120 and the barrel 110.

[0065] Furthermore, with this configuration, the entire portion of upper plunger 120 except for expanded diameter terminal portion 123 is housed (visually hidden) in barrel 110 during inspection. Therefore, contact probe 100B has a substantially constant diameter overall during inspection, making it possible to further eliminate impedance mismatch.

[0066] [Variation 2] As shown in FIG. 16, a tip 132 of the lower plunger 130 may also be provided with an expanded diameter terminal portion 133 .

[0067] According to this configuration, contact probe 100B can be made to have a substantially constant diameter as a whole, and similarly to upper plunger 120, impedance mismatch can be eliminated during testing.

[0068] [Third embodiment] An inspection socket according to a third embodiment of the present invention will now be described with reference to the drawings. The inspection socket according to this embodiment has a different receiving hole shape from the inspection socket according to the first embodiment, but the other configurations are the same, and therefore the same components are denoted by the same reference numerals and descriptions thereof will be omitted.

[0069] As shown in FIG. 18, the movable base 700 has an accommodating hole 710 formed along the X-axis direction. The tip 122 side of the upper plunger 120 is inserted into the accommodation hole 710, and the solder balls 31 of the IC package 30 placed on the movable pedestal 700 are accommodated therein (see FIGS. 8 and 9).

[0070] A guide portion 711 is formed in a receiving hole 710 formed in the movable base 700 .

[0071] Guide portion 711 is a portion formed at the bottom of accommodation hole 710, and its inner diameter is approximately the same diameter (more precisely, slightly larger diameter) as the outer diameter of the portion of barrel 110 other than flange portion 114. This makes it possible to guide the portion of barrel 110 protruding from upper housing 201.

[0072] The length of the upper plunger 120 is set so that when the upper plunger 120 is pressed into the barrel 110 by the solder ball 31 during testing, the tip 122 is housed within the barrel 110. This allows the upper plunger 120 to be entirely hidden within the barrel 110.

[0073] According to this embodiment, the following effects are obtained. During testing, upper plunger 120 is entirely housed (visibly hidden) within barrel 110. Therefore, during testing, contact probe 500 has a substantially constant diameter overall, making it possible to eliminate impedance mismatch. [Explanation of symbols]

[0074] 10 Socket (Inspection socket) 20 Printed wiring board (test board) 30 IC package (test device) 31 Solder ball (electrode) 100A, 100B Contact probe (contact terminal) 110 barrels 111 Upper end (one end) 112 Bottom end (other end) 114 Flange part 120 Upper plunger (device side terminal) 121 Proximal end 122 Tip 123 Expanded diameter terminal section 130 Lower plunger (test board side terminal) 131 Proximal end 132 Tip 133 Expanded diameter terminal section 140 Spring 200 Housing 201 Upper housing 202 Lower housing 210 Stepped hole 211 Multilayered section 212 Reduced diameter section 300 Movable base 301 Upper pedestal 302 Lower pedestal 310 Storage hole 311 Guide part 312 Counterbore 320 Recess 401 Pedestal spring 500 Contact probe (contact terminal) 700 Movable base 710 Storage hole 711 Guide part

Claims

1. a contact terminal including: a barrel that is a cylindrical body extending along an axial direction and has a flange portion that protrudes radially from an outer peripheral surface of the cylindrical body; a device side terminal that is accommodated at one end of the barrel and has a tip that contacts a testing device; a test board side terminal that is accommodated at the other end of the barrel and has a tip that contacts a test board; and a spring that contacts the test board side terminal and the device side terminal within the barrel; a housing having a stepped hole through which the contact terminal is inserted along the axial direction and having a stepped portion formed in the housing that abuts against the flange portion in the axial direction; a movable base provided to be movable toward or away from the housing, the movable base having an accommodation hole into which a tip end side of the device side terminal protruding from the barrel is inserted and into which an electrode of the testing device is accommodated; Equipped with An inspection socket in which a guide portion is formed in the accommodating hole of the movable base, the guide portion having an inner diameter that is approximately the same as the outer diameter of the portion of the device side terminal protruding from the barrel and that is independent of the size of the electrode of the inspection device.

2. 2. The inspection socket according to claim 1, wherein the receiving hole of the movable base is formed with a counterbore portion for receiving the barrel protruding from the housing.

3. 3. The inspection socket according to claim 2, wherein the countersunk portion is formed integrally and continuously with another adjacent countersunk portion.

4. 4. The inspection socket according to claim 1, wherein the movable base is divided in the axial direction.

5. 5. The inspection socket according to claim 3, wherein the device-side terminal is provided at a tip thereof with an enlarged diameter terminal portion having substantially the same diameter as the barrel.

6. 5. The testing socket according to claim 3, wherein the device-side terminals and the test board-side terminals are provided at their tips with enlarged diameter terminal portions having substantially the same diameter as the barrel.

7. 7. The inspection socket according to claim 5, wherein the device-side terminal is set to a length dimension such that the enlarged terminal portion contacts the one end of the barrel during inspection.

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