Test probe

Abstract

According to an embodiment of the disclosure, there is provided a test probe for testing electrical characteristics of an object to be tested. The test probe includes: a barrel including a tubular barrel main body, and a plurality of skirt portions separated from each other by a plurality of slits formed longitudinally in a first end portion of the barrel main body; and a plunger including a sliding portion slidable along an axial line of the barrel as accommodated in the barrel main body, and a terminal contact portion extending from the sliding portion beyond the skirt portion along a direction of the axial line. The skirt diameter-reducing portion has a nominal thickness that decreases from a center region to an edge region along a circumferential direction when viewed in the direction of the axial line.

Description

TEST PROBE

[0001] The disclosure relates to a test probe for testing the electrical characteristics of an object to be tested, such as a semiconductor.

[0002] The test probe includes a cylindrical barrel, a plunger coupled slidably within a first side of the barrel, a terminal fixedly coupled to a second side of the barrel, and a spring interposed between the plunger and the terminal within the barrel to provide an elastic force.

[0003] To ensure stable contact between the plunger and the barrel, there has been disclosed a test probe having a plurality of skirt portions formed by a plurality of slits cut longitudinally in a first side end portion of the barrel into which the plunger is inserted. However, such a conventional test probe has a problem in that the plunger sliding during a test is scratched by the sharp edges of the slits, thereby degrading durability or causing a plating layer formed on the outer surface of the plunger to peel off.

[0004] An aspect of the disclosure is to provide a test probe, which is improved in durability and test reliability.

[0005] According to an embodiment of the disclosure, there is provided a test probe for testing electrical characteristics of an object to be tested. The test probe includes: a barrel including a tubular barrel main body, and a plurality of skirt portions separated from each other by a plurality of slits formed longitudinally in a first end portion of the barrel main body; and a plunger including a sliding portion slidable along an axial line of the barrel as accommodated in the barrel main body, and a terminal contact portion extending from the sliding portion beyond the skirt portion along a direction of the axial line. The skirt diameter-reducing portion has a nominal thickness that decreases from a center region to an edge region along a circumferential direction when viewed in the direction of the axial line.

[0006] The skirt diameter-reducing portion may include an inner surface portion facing the terminal contact portion, and an outer surface portion reduced in diameter from an outer surface of the skirt main body. The inner surface portion may have a radius of curvature larger than an outer peripheral portion of the outer surface portion when viewed in the direction of the axial line. Thus, the contact pressure of the skirt diameter-reducing portion against the outer circumferential surface of the terminal contact portion is decreased.

[0007] The inner surface portion may include a flat surface. Thus, the front end of the skirt diameter-reducing portion comes into line-contact with the outer circumferential surface of the terminal contact portion.

[0008] The terminal contact portion may have a cross-section corresponding to an opening shape formed by the skirt diameter-reducing portions of the plurality of skirt portions. Thus, the scratches of the terminal contact portion are avoided or the plating layer thereof is prevented from peeling off, and the surface area of the plunger is increased to reduce electrical resistance.

[0009] The slit may be shaped to become narrower inward in a radial direction when viewed in the direction of the axial line. Thus, it is possible to increase the length from the center region to the edge region of the skirt diameter-reducing portion, and it is thus possible to adjust a degree of reduction in the nominal thickness according to design conditions.

[0010] In the test probe according to an embodiment of the disclosure, the outer circumferential surface of the plunger is prevented from coming into contact with the edges of the plurality of slits longitudinally cut at regular intervals along a circumferential direction in the first end portion of the barrel, thereby avoiding scratches on the plunger or preventing the plating layer on the outer circumferential surface of the plunger from peeling off.

[0011] Further, the impedance characteristics are improved while ensuring the contact between the front end of the skirt portion and the outer circumferential surface of the plunger.

[0012] FIG. 1 is a view showing an overall test probe according to a first embodiment of the disclosure.

[0013] FIG. 2 is an exploded view of the test probe of FIG. 1.

[0014] FIG. 3 is a cross-sectional view of the test probe, taken along the axial line of FIG. 1.

[0015] FIG. 4 is an enlarged view of a first end portion of a barrel of FIG. 2.

[0016] FIG. 5 is a view of the test probe of FIG. 1 from the axial line.

[0017] FIG. 6 is a view showing an overall test probe according to a second embodiment of the disclosure.

[0018] FIG. 7 is a view showing a plunger of FIG. 6.

[0019] FIG. 8 is a view showing the test probe of FIG. 6 viewed in the direction of the axial line.

[0020] Below, a test probe and a test device according to embodiments of the disclosure will be described in detail with reference to the accompanying drawings.

[0021] Below, a test probe 1 according to an embodiment of the disclosure will be described in detail with reference to the accompanying drawings. Hereinafter, the "axial line O" indicates the line of the central axis of the test probe 1 in a longitudinal direction.

[0022] For example, a test apparatus for testing the electrical characteristics of a semiconductor or the like object to be tested includes a probe support shaped like a plate, and a test probe 1 supported so that both end portions thereof can partially protrude from the upper and lower surfaces of the probe support.

[0023] FIG. 1 is a view showing an overall test probe according to a first embodiment of the disclosure, FIG. 2 is an exploded view of the test probe of FIG. 1, FIG. 3 is a cross-sectional view of the test probe, taken along the axial line O of FIG. 1, FIG. 4 is an enlarged view of a first end portion of a barrel 11 of FIG. 2, and FIG. 5 is a view of the test probe of FIG. 1 from the axial line.

[0024] Referring to FIGS. 1 to 5, the test probe 1 includes, for example, a cylindrical barrel 11, a plunger 12 coupled slidably within a first side of the barrel 11, a terminal 13 fixedly coupled to a second side of the barrel 11, and an elastic member 14 interposed between the plunger 12 and the terminal 13 within the barrel 11 to provide an elastic force.

[0025] The barrel 11 includes a barrel main body 110, and a skirt portion 112 separated by a plurality of slits 111 formed at predetermined intervals along the longitudinal direction in a first side end portion into which the plunger 12 is inserted.

[0026] The plurality of slits 111 are shaped to become narrower inward in a radial direction when viewed in the direction of the axial line O, as shown in FIG. 5. As a result, a distal edge 115C of a skirt diameter-reducing portion 114 (to be described later) may be positioned as biased outward in the radial direction of the barrel 11 so as not to come into contact with the outer circumferential surface of a terminal contact portion 122.

[0027] The number of slits 111 is not limited to three, but may be two or four or more. The slits 111 may have a shape that gradually narrows toward the barrel main body 110.

[0028] The barrel main body 110 has a cylindrical shape in which the elastic member 14 is accommodated.

[0029] The skirt portion 112 includes a skirt main body 113 extending along the barrel main body 110, and the skirt diameter-reducing portion 114 bent from a front end region of the skirt main body 113 so as to be reduced in diameter toward the axial line O of the barrel 11.

[0030] The skirt main body 113 extends from the barrel main body 110 while having the same diameter and thickness as the barrel main body 110.

[0031] Referring to FIGS. 4 and 5, the skirt diameter-reducing portion 114 has an inner surface portion 115 facing the outer circumferential surface of the terminal contact portion 122 in the front end region, an outer surface portion 116 abutting on the skirt main body 113, an inner side portion 117 connecting the inner surface portion 115 and the outer surface portion 116 on the inner side of the barrel 11, and an outer side portion 118 connecting the inner surface portion 115 and the outer surface portion 116 on the outer side of the barrel 11.

[0032] The inner surface portion 115 may be in line-contact with the circular circumferential surface (curved surface) of the terminal contact portion 122. The inner surface portion 115 may be a flat surface. Alternatively, as illustrated by the dotted line in FIG. 5, the inner surface portion 115 may be a curved surface having a radius of curvature that is much larger than, for example, 100 times or more larger than that of an outer peripheral portion 116a of the outer surface portion 116, when viewed in the direction of the axial line O.

[0033] The outer surface portion 116 refers to a curved surface formed to be inclined in a direction where the diameter is reduced from the skirt main body 113. An outer peripheral portion of the outer surface portion 116 refers to a portion that abuts onto the skirt main body 113.

[0034] The inner side portion 117 is shaped to correspond to the shape of a stepped portion 123 between a sliding portion 121 and the terminal contact portion 122 of the plunger 12 (to be described later). The plunger 12 is prevented from coming out of the barrel 11 because the stepped portion 123 is caught on the inner side portion 117.

[0035] The outer side portion 118 refers to a flat surface formed in the transverse direction of the axial line O from an inner peripheral portion 116b of the outer surface portion 116. The outer surface portion 118 may be omitted such that the outer surface portion 116 and the inner surface portion 115 are in direct contact with each other.

[0036] In FIG. 5, the skirt diameter-reducing portion 114 has a nominal thickness t1 that decreases from a center region to an edge region along a circumferential direction when viewed in the direction of the axial line O. Here, the nominal thickness t1 may be defined as a radial distance that is visually measurable when viewed in the direction of the axial line O. In the case of three slits 111, such a reduction in the nominal thickness t1 causes edges 115C of the skirt diameter-reducing portion 114, i.e., the edges 115C of the inner surface portion 115, which abuts onto the slits 111, to be spaced apart from the outer circumferential surface of the terminal contact portion 122. As a result, the outer circumferential surface of the terminal contact portion 122 does not come into contact with the edges 115C of the inner surface portion 115, thereby improving the durability of the plunger 12. In addition, because the slit 111 narrows radially inward when viewed in the direction of the axial line O, it is possible to increase the length from the center region to the edge region of the skirt diameter-reducing portion 114, and it is thus possible to adjust a degree of reduction in the nominal thickness t1 according to the design conditions.

[0037] The plunger 12 includes the sliding portion 121 that slides as accommodated in the barrel main body 110; the terminal contact portion 122 that extends from the sliding portion 121, is exposed to the outside through the skirt portion 112, and comes into contact with the skirt portion 112; and the stepped portion 123 formed between the sliding portion 121 and the terminal contact portion 122.

[0038] The sliding portion 121 has a diameter corresponding to the inner diameter of the barrel main body 110. The diameter of the sliding portion 121 is set to be smaller than the inner diameter of the barrel main body 110 so as to slide within the barrel main body 110. The sliding portion 121 has an inner end portion that faces the barrel main body 110 and is in contact with a first side of the elastic member 14. The sliding portion 121 slides within the barrel main body 110 along the direction of the axial line O according to the compression or restoration of the elastic member 14.

[0039] The terminal contact portion 122 has a diameter smaller than that of the sliding portion 121. The diameter of the terminal contact portion 122 is set to pass by the front end of the skirt portion 112 while facing the front end of the skirt portion 112. The end portion of the terminal contact portion 122 comes into contact with a terminal (not shown) for a test, for example, a pad terminal of a test circuit board.

[0040] The stepped portion 123 faces the inner side portion 117 (see FIG. 4) of the skirt diameter-reducing portion 114, and catches and restrains the plunger 12 that tends to come out of the barrel 11 due to the elastic member 14.

[0041] The terminal 13 is fixedly connected to a second end portion of the barrel 11 by dimpling or cocking. As an alternative example, the terminal 13 may be inserted so as to be not fixed but slidable. An inner end portion of the terminal 13 inserted into the barrel 11 is in contact with a second side of the elastic member 14. An outer end portion of the terminal 13 may have sharp tips 131 that come into contact with a bump terminal of an object to be tested, such as a semiconductor.

[0042] The elastic member 14 is compressed and restored as the plunger 12 slides during the test. The elastic member 14 may for example be implemented by a coil spring.

[0043] FIG. 6 is a view showing an overall test probe 1 according to a second embodiment of the disclosure, FIG. 7 is a view showing a plunger 15 of FIG. 6, and FIG. 8 is a view showing the test probe 1 of FIG. 6 viewed in the direction of the axial line O. Below, components identical to those shown in FIG. 1 will not be described to avoid redundant description.

[0044] Referring to FIGS. 6 to 8, the plunger 15 includes a sliding portion 151 that slides as accommodated in the barrel main body 110; a terminal contact portion 152 that extends from the sliding portion 151, is exposed to the outside through the skirt portion 112, and comes into contact with the skirt portion 112; and a stepped portion 153 formed between the sliding portion 151 and the terminal contact portion 152.

[0045] The sliding portion 151 has a diameter corresponding to the inner diameter of the barrel main body 110. The sliding portion 151 slides within the barrel main body 110 along the direction of the axial line O according to the compression or restoration of the elastic member 14.

[0046] The terminal contact portion 152 includes three flat portions 152a cut to have flat surfaces along the direction of the axial line O, and three curved portions 152b provided between two adjacent flat portions 152a. Each number of flat portions 152a and curved portions 152b corresponds to the number of slits 111 formed in the end portion of the barrel 11. The three flat portions 152a face the inner surface portions 115 of three skirt diameter-reducing portions 114, and the three curved portions 152b face three slits 111. As a result, the terminal contact portion 152 has a cross-section corresponding to an opening shape formed by the inner surface portions 115 of the three skirt diameter-reducing portions 114. In this way, the terminal contact portion 152 is formed to have a triangular cross-section, the cross-section area of which is larger than that of a circular cross-section, thereby having improved resistance characteristics and durability. In addition, the flat portion 152a of the terminal contact portion 152 is in surface-contact with the inner surface portion 115 of the skirt diameter-reducing portion 114, and thus prevented from coming into contact with the edges of the inner surface portion 115 of the skirt diameter-reducing portion 114, thereby avoiding scratches on a plating layer thereof.

[0047] The inner surface portion 115 of the skirt diameter-reducing portion 114 is formed by flat cutting machining with a T-shaped cutter, which is easier than curved surface machining, thereby reducing manufacturing costs.

[0048] Although a few embodiments of the disclosure have been illustrated and described above, the disclosure is not limited to the foregoing specific embodiments. Various modifications can be made in the embodiments by those skilled in the art without departing from the scope of the disclosure as claimed in Claims, and these modified embodiments should not be understood separately from the technical spirits or prospects of the disclosure.

Claims

1.A test probe for testing electrical characteristics of an object to be tested, the test probe comprising:a barrel comprising a tubular barrel main body, and a plurality of skirt portions separated from each other by a plurality of slits formed longitudinally in a first end portion of the barrel main body; anda plunger comprising a sliding portion slidable along an axial line of the barrel as accommodated in the barrel main body, and a terminal contact portion extending from the sliding portion beyond the skirt portion along a direction of the axial line,wherein the skirt portion comprises a skirt main body extending in a longitudinal direction of the barrel main body, and a skirt diameter-reducing portion bent from a front end region of the skirt main body so as to be reduced in diameter toward the axial line of the barrel and coming into contact with the terminal contact portion, andthe skirt diameter-reducing portion has a nominal thickness that decreases from a center region to an edge region along a circumferential direction when viewed in the direction of the axial line.2.The test probe of claim 1, whereinthe skirt diameter-reducing portion comprises an inner surface portion facing the terminal contact portion, and an outer surface portion reduced in diameter from an outer surface of the skirt main body, andthe inner surface portion has a radius of curvature larger than an outer peripheral portion of the outer surface portion when viewed in the direction of the axial line.3.The test probe of claim 2, wherein the inner surface portion comprises a flat surface.4.The test probe of claim 3, wherein the terminal contact portion has a cross-section corresponding to an opening shape formed by the skirt diameter-reducing portions of the plurality of skirt portions.5.The test probe of claim 1, wherein the slit is shaped to become narrower inward in a radial direction when viewed in the direction of the axial line.

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