Testing probe and test socket having the same

Abstract

The present invention provides an inspection socket that transmits a test signal from the lower plunger through the tightly wound portion of the coil spring to the upper plunger by using an inspection probe comprising a coil spring having a tightly wound portion on the upper side, a lower plunger fitted to the lower side of the coil spring and slidably contacting the inner side of the tightly wound portion of the coil spring, and an upper plunger contacting the upper side of the tightly wound portion of the coil spring.

Description

Technology Field

[0001] The present invention relates to an inspection probe and an inspection socket including the same, and more specifically, to an inspection probe used to inspect the electrical characteristics of a device to be inspected, such as a printed circuit board, a liquid crystal display board, a semiconductor package, a semiconductor wafer, or a camera module, and an inspection socket equipped with the inspection probe. Background Technology

[0002] The device under inspection is formed by the high-density integration of fine electronic circuits, and undergoes a testing process during the manufacturing process to verify the functionality of each circuit. This testing process is designed to distinguish between good and defective products by checking whether the device operates normally.

[0003] In the process of testing a device under test, a tester is used to electrically connect the terminals of the device under test to the pads of the tester that apply the test signal. The tester has various structures depending on the type of device under test. The tester and the device under test are not directly connected to each other, but are connected indirectly through a test socket.

[0004] Pogo pins, which have a structure in which a socket pin is installed inside the socket barrel, are mainly used as inspection probes for conventional inspection sockets.

[0005] Figure 1 shows a conventional inspection socket using a pogo pin as an inspection probe, and Figure 2 shows a conventional pogo pin.

[0006] An inspection socket (60) using pogo pins is formed by placing pogo pins (50) in holes formed in the upper support member (30) and the lower support member (40), respectively, and the upper pin (52) of the pogo pin (50) is positioned to be electrically connected to a terminal of a device to be inspected (not shown), and the lower pin (53) is positioned to be electrically connected to a pad of a tester (not shown) so that it can be used to perform an electrical test on the device to be inspected.

[0007] As shown in FIG. 2, the pogo pin (50) is typically formed such that an upper pin (52) connected to a device under test and a lower pin (53) connected to a tester are respectively arranged on the upper and lower parts of the barrel (51), and a spring (54) is interposed between the upper pin and the lower pin to have its own elasticity. A plurality of tip portions (57) capable of improving contact with the terminal of the device under test may be provided on the upper side of the upper pin (52).

[0008] The upper (55) and lower (56) of the cylindrical barrel at the pogo pin (50) are each caulked to prevent the upper pin (52) and lower pin (53) from detaching from the barrel (51) and are assembled. Since it is preferable for the electrical connection of the pogo pin (50) to be formed between the upper pin, the lower pin, and the barrel, the pogo pin is formed of a conductive material such as a gold-coated copper alloy.

[0009] The upper pin (52) of the pogo pin (50) undergoes wear through repeated contact with the terminal of the device under test thousands to hundreds of thousands of times. Furthermore, if the device under test is a semiconductor package, as the number of uses increases, tin, which is the main component of the solder ball used as a terminal, is transferred to the upper pin. When current is applied for testing, heat is generated due to the contact resistance between the upper pin and the surface of the solder ball, which promotes the oxidation of tin. Consequently, a problem arises where electrical characteristics cannot be maintained due to the increase in electrical resistance of the transferred tin surface. As such, since the upper pin is a component that repeatedly contacts the terminal of the device under test, wear, tin transfer, or an increase in contact resistance due to tin oxidation cannot be avoided.

[0010] Various cleaning methods are used to reduce the resistance of the tin surface, which has increased due to wear, tin transfer, and tin oxidation of the upper pin (52), to a state close to that before use. For example, a method of separating and vaporizing the interface by applying a high-temperature laser beam to the upper pin due to the difference in thermal expansion between the transferred tin oxide and the surface material of the upper pin, a friction method using a brush to remove tin oxide by mechanical friction, a method of removing the tin oxide film by a chemical substance such as alcohol, a method of separating and removing tin oxide by spraying dry ice particles at high pressure due to the difference in thermal expansion, or a method of removing tin oxide by placing it in an ultrasonic cleaning tank and applying micro-vibrations with ultrasound.

[0011] However, the friction method using a brush accelerates the wear of the upper pin, and since materials such as gold (Au) coated on the surface of the upper pin before use are alloyed with tin transferred by heat and pressure from repeated use, it is difficult to remove tin oxide with a brush. On the contrary, due to insufficient or uneven effectiveness, it lowers the operating rate of expensive inspection equipment and semiconductor ATE (Automated Test Equipment) equipment, and as cleaning is repeated, the cleaning cycle becomes shorter, which leads to an increase in manpower input.

[0012] Since reuse through cleaning can actually increase the total inspection costs, some users intend to adopt a procedure of replacing the entire pogo pin with a new one after a certain number of uses; however, the reality is that this procedure is not being actively adopted due to the high cost of pogo pin replacement. In other words, even if the upper pin reaches the end of its lifespan due to wear, tin transfer, or tin oxidation, the entire pogo pin must be replaced because the upper pin, lower pin, coil spring, and barrel are manufactured as a single integrated unit; this does not allow for the replacement of only the upper pin. Consequently, this leads to increased costs and reduced operational efficiency of inspection equipment, posing a problem that requires additional investment in inspection equipment and personnel.

[0013] In addition, to increase inspection productivity, the number of Device Under Test (DUT) units that can be inspected simultaneously has exceeded 768 DUT parallels for memory semiconductors and reached 1,024 DUT parallels, while for non-memory semiconductors, it has increased from 64 DUT parallels to 128 DUTs and 256 DUT parallels. However, as the company's inspection volume increases, the occurrence of DUT Off due to inspection probe degradation (a function that recognizes a problem with the inspection probe when continuous inspection defects occur more than a specified number of times, thereby preventing further inspection by not mounting a device under test on the corresponding DUT) also increases. Consequently, the reduction in production volume resulting from the shutdown of inspection equipment to repair this becomes even greater. As a result, the problem of reduced equipment production is recurring, where equipment continues to operate without repairs to avoid shutdown even when DUT Off levels exceed a certain threshold.

[0014] Furthermore, test sockets require good high-frequency signal transmission characteristics for more accurate testing. To improve signal transmission characteristics, it is necessary to match the impedance of the test socket, including the pogo pins, to the impedance of the device under test.

[0015] Impedance has the characteristic of being proportional to inductance and inversely proportional to capacitance. Since inductance increases as the diameter of the current line decreases and decreases as the diameter increases, inductance can be adjusted by changing the diameter of the pogo pin in a test socket. However, the pogo pins used in conventional test sockets consist of a barrel and a coil spring housed inside, and the test current is transmitted to the upper pin through the lower pin and the barrel. As the pitch between the terminals of the device under test decreases, reducing the outer diameter of the barrel increases the manufacturing cost of the barrel, and since the wire diameter and center diameter of the coil spring housed inside must be smaller, durability is reduced and costs increase. In other words, there is a problem in that it is difficult to achieve a large range of inductance variation through diameter changes in the conventional pogo pin structure. Prior art literature

[0016] Published Patent Application No. 10-2022-0043866 (April 5, 2022) The problem to be solved

[0017] The present invention has been devised in consideration of the points described above, and aims to provide an inspection probe and an inspection socket including the same, wherein the upper plunger can be easily replaced by using an upper plunger separated from the elastic part, without using an expensive barrel by configuring the elastic part with a spring and a lower plunger. means of solving the problem

[0018] The inspection probe according to the present invention for solving the above-described purpose comprises an upper support member and a lower support member having support holes formed at positions corresponding to the terminal, and an elastic inspection probe positioned to be inserted into the support holes to prevent detachment, wherein the inspection probe comprises an upper plunger capable of contacting the terminal, a lower plunger capable of contacting the pad, and a coil spring having a lower plunger fitted on the lower side and a tightly wound portion on the upper side, wherein the upper plunger comprises a first contact portion capable of contacting the terminal and a second contact portion capable of contacting the tightly wound portion, wherein the upper end of the tightly wound portion contacts the second contact portion, and the inner side of the tightly wound portion contacts the lower plunger in a sliding manner.

[0019] The lower plunger has a boss portion with a diameter larger than the inner diameter of the coil spring, and the coil spring can be fitted and fixed to the boss portion.

[0020] The upper part of the above tightly wound portion may have a smaller diameter than the lower part.

[0021] The upper plunger may have a hemispherical third contact portion below the second contact portion, and the third contact portion may be made to contact the inner side of the tightly wound portion.

[0022] The second contact portion of the upper plunger has an upper flange portion and a flange extension portion formed on the lower side of the upper flange portion, and the flange extension portion can be made to come into contact with the upper end of the tightly wound portion.

[0023] The upper plunger is provided with a guide portion extending downward from the second contact portion, and the guide portion can be inserted into the inner side of the tightly wound portion.

[0024] A densely wound portion may also be symmetrically provided on the lower side of the above coil spring.

[0025] In addition, the inspection probe according to the present invention is disposed between a device to be inspected having a terminal and a tester having a pad, and comprises an upper support member and a lower support member having support holes formed at positions corresponding to the terminal, and an elastic inspection probe disposed to be fitted into the support holes to prevent detachment, wherein the inspection probe comprises an upper plunger capable of contacting the terminal, a lower plunger capable of contacting the pad, and a cylindrical tubular spring having a spiral spring portion provided on the lower side and a connection portion provided on the upper side, wherein the lower plunger is fitted into the lower side of the tubular spring, and the upper plunger has a first contact portion capable of contacting the terminal and a second contact portion capable of contacting the tubular spring, wherein the upper end of the connection portion contacts the second contact portion, and the inner side of the connection portion contacts the lower plunger so as to be slidably contact.

[0026] In addition, the inspection socket according to the present invention is an inspection socket that performs an electrical inspection of a device to be inspected by connecting a terminal of the device to be inspected to a pad of a tester that generates an inspection signal, and comprises an upper support member and a lower support member disposed between the device to be inspected and the tester, each having a support hole formed at a position corresponding to the terminal, and an elastic inspection probe disposed to be inserted into each of the support holes to prevent detachment, wherein the inspection probe comprises an upper plunger capable of contacting the terminal, a lower plunger capable of contacting the pad, and a coil spring having a portion that is tightly wound on the upper side and has the lower plunger fitted and fixed on the lower side, wherein the upper plunger has a first contact portion capable of contacting the terminal and a second contact portion capable of contacting the tightly wound portion, wherein the upper end of the tightly wound portion contacts the second contact portion and the inner side of the tightly wound portion contacts the lower plunger so as to be slidably contact.

[0027] A lower cover may be provided on the lower side of the upper support member, having a lower cover hole formed with a diameter smaller than the diameter of the second contact portion and larger than the outer diameter of the coil spring.

[0028] The lower plunger comprises a head portion that contacts the pad, a lower flange portion that contacts the coil spring, and a rod portion that can contact the inner side of the tightly wound portion, and an upper cover may be provided on the upper side of the lower support member, the upper cover having an upper cover hole formed with a diameter smaller than the diameter of the lower flange portion and larger than the outer diameter of the coil spring. Effects of the invention

[0029] In the test probe and test socket using the same according to the present invention, since the upper plunger that repeatedly contacts the terminal of the device to be tested is provided as a separate component, only the upper plunger that has reached the end of its lifespan can be easily replaced, and the coil spring and lower plunger can be reused, thereby minimizing waste of parts and significantly reducing maintenance costs.

[0030] In the test probe and test socket using the same according to the present invention, since the upper plunger is not fixed to the coil spring and a signal is transmitted by the upper plunger contacting the top of the coil spring combined with the lower plunger, the signal transmission length is reduced by omitting the fixing part, thereby improving high-frequency transmission characteristics, and the manufacturing cost is reduced by reducing the length of the upper plunger, which uses expensive precious metal materials such as palladium alloy.

[0031] The inspection probe and test socket using the same according to the present invention can be configured by simple joining without using an expensive barrel and without mechanical or elastic fixing processes such as crimp fitting, soldering, or welding to integrate the coil spring, upper plunger, and lower plunger, so the structure is simple, manufacturing time is shortened, and manufacturing costs can be significantly reduced.

[0032] The test probe and test socket using the same according to the present invention transmit the test signal through the tightly wound portion of the coil spring, so even if the number of windings in the loosely wound portion increases to obtain the necessary elastic force, the test signal can be transmitted without passing through the loosely wound portion, thereby reducing electrical resistance and improving the accuracy of the test, and preventing high frequency from flowing through the loosely wound portion, thereby improving high frequency transmission characteristics.

[0033] The inspection probe and test socket using the same according to the present invention can have a coil spring integrally fixed to the boss portion of the lower plunger, so work productivity can be significantly improved when assembling the inspection probe to a support member.

[0034] The test probe and test socket using the same according to the present invention have the advantage of improving high-frequency signal transmission characteristics by increasing the range of choices for matching the impedance of the device under test, as the capacitance proportional to the surface area can be reduced and the inductance proportional to the length and inversely proportional to the diameter can be increased, thereby reducing the diameter of the upper part of the tightly wound portion of the coil spring and reducing the diameter of the rod portion of the lower plunger accordingly.

[0035] The inspection probe and test socket using the same according to the present invention can improve the accuracy of inspection by reducing the overall resistance of the inspection probe, as the contact area is increased by forming a hemispherical third contact portion on the lower part of the upper plunger, thereby allowing the upper plunger to contact the upper end of the tightly wound portion of the coil spring and simultaneously contact the inner side of the tightly wound portion.

[0036] The inspection probe and test socket using the same according to the present invention can form a long inspection probe by utilizing a pre-fabricated coil spring and lower plunger as they are and manufacturing a long upper plunger as a flange extension when it is necessary to place a long inspection probe corresponding to a large warpage of the device under inspection or to increase the length of the inspection probe due to the need to increase the thickness of the test socket. This allows the inspection probe to be formed in such cases, thereby easily accommodating changes in the warpage of the device under inspection or the thickness of the test socket, and thus significantly increasing the usability of the inspection probe.

[0037] The inspection probe and test socket using the same according to the present invention can stably maintain the compression operation of the coil spring by providing a guide portion at the lower part of the upper plunger so that the tightly wound portion of the coil spring can be positioned at the center of the second contact portion of the upper plunger.

[0038] The inspection probe and test socket using the same according to the present invention are provided with a densely wound portion provided on the upper side of the coil spring and a densely wound portion provided on the lower side of the coil spring symmetrically to each other, so that the directionality of the coil spring does not need to be considered during the automatic alignment process using vibration and a jig during the assembly process of the inspection probe, thereby facilitating alignment and improving assembly productivity.

[0039] The inspection probe and test socket using the same according to the present invention utilize a tubular spring with a thinner thickness instead of a coil spring, thereby enabling the manufacture of an inspection probe with a thinner diameter, which allows for easy adaptation to devices under inspection with fine pitch. Furthermore, since the inspection probe with a thinner diameter offers greater potential to increase impedance, it has the effect of improving high-frequency signal transmission characteristics.

[0040] The test socket according to the present invention has the advantage of enabling rapid replacement, reducing replacement costs, and facilitating maintenance of the Automated Test Equipment (ATE) equipment coupled with the test socket, as it can support the upper plunger so that it does not detach by attaching a lower cover to an upper support member and support the lower plunger so that it does not detach by attaching an upper cover to a lower support member. Brief explanation of the drawing

[0041] FIG. 1 is an exploded perspective view showing an inspection socket using a conventional pogo pin. Figure 2 is a drawing showing the pogo pins of a conventional inspection socket. FIG. 3 is a drawing showing an inspection socket according to a first embodiment of the present invention. FIG. 4 is an exploded perspective view showing an inspection probe according to a first embodiment of the present invention. FIG. 5 is a partial cross-sectional view of a test socket equipped with an inspection probe according to a first embodiment of the present invention. FIG. 6 is a partial cross-sectional view of a test socket equipped with an inspection probe according to a second embodiment of the present invention. FIG. 7 is a partial cross-sectional view of a test socket equipped with an inspection probe according to a third embodiment of the present invention. FIG. 8 is a partial cross-sectional view of a test socket equipped with an inspection probe according to a fourth embodiment of the present invention. FIG. 9 is a partial cross-sectional view of a test socket equipped with an inspection probe according to a fifth embodiment of the present invention. FIG. 10 is a partial cross-sectional view of a test socket equipped with an inspection probe according to a sixth embodiment of the present invention. FIG. 11 is a partial cross-sectional view of a test socket equipped with an inspection probe according to the seventh embodiment of the present invention. FIG. 12 is a partial cross-sectional view of a test socket equipped with an inspection probe according to the eighth embodiment of the present invention. Figure 13 is a drawing showing a tubular spring. FIGS. 14 and 15 are drawings showing a first modified example of a test socket using an inspection probe according to the first to eighth embodiments. FIGS. 16 and 17 are drawings showing a second modified example of a test socket using an inspection probe according to the first to eighth embodiments. Specific details for implementing the invention

[0042] Hereinafter, an inspection probe according to the present invention and an inspection socket including the same will be described in detail with reference to the drawings.

[0043] In the present invention, since the device to be tested is located on the upper side of the test socket and the tester is located on the lower side, the 'upper surface,' 'upper side,' 'top,' 'lower side,' 'bottom,' etc. of any component will be described based on this. Additionally, the same reference numerals are used for identical components, and their descriptions are omitted.

[0044] FIG. 3 shows an inspection socket according to a first embodiment of the present invention, FIG. 4 is an exploded perspective view showing an inspection probe according to a first embodiment of the present invention, and FIG. 5 is a partial cross-sectional view of a test socket equipped with an inspection probe according to a first embodiment of the present invention.

[0045] As shown in FIGS. 3 to 5, the test socket (1000) according to the first embodiment of the present invention is intended to perform an electrical test on a device to be tested by connecting a terminal (11) of the device to be tested (10) to a pad (21) of a tester (20) that generates a test signal.

[0046] The inspection socket (1000) is positioned between the device to be inspected (10) and the tester (20), and includes an upper support member (100) and a lower support member (200) having support holes (110, 210) formed at positions corresponding to terminals (11), and an inspection probe (300) positioned to be inserted into each of the support holes (110, 210) to prevent detachment.

[0047] The upper support member (100) and the lower support member (200) are joined together to support a plurality of inspection probes (300) at a portion where a part of the inspection probe (300) is mounted. The upper support member (100) and the lower support member (200) may be joined by a screw connection method or by another method.

[0048] In the upper support member (100), a cylindrical upper support hole (110) into which an inspection probe (300) is inserted is formed to penetrate in the thickness direction of the upper support member (100), that is, in the vertical direction. Near the upper end of the upper support hole (110), an upper stopper (120) with a reduced diameter is provided. In the lower support member (200), a cylindrical lower support hole (210) into which an inspection probe (300) is inserted is formed to penetrate in the thickness direction of the lower support member (200). Near the lower end of the lower support hole (210), a lower stopper (220) with a reduced diameter is provided. Between the upper stopper (120) and the lower stopper (220), the upper support hole (110) and the lower support hole (210) have a diameter that is relatively larger than the reduced diameter formed at the end and have diameters that match each other.

[0049] The inspection probe (300) is composed of an upper plunger (310) capable of contacting a terminal of a device to be inspected, a lower plunger (320) capable of contacting a pad of a tester, and a coil spring (330) having a lower plunger (320) fitted on the lower side and a tightly wound portion (331) on the upper side, wherein the upper plunger (310) is provided with a first contact portion (311) capable of contacting a terminal (11) and a second contact portion (315) capable of contacting the tightly wound portion (331), and the upper end of the tightly wound portion (331) is in contact with the second contact portion (315), and the inner side of the tightly wound portion (331) is configured so that the lower plunger (320) can slideably contact it.

[0050] The upper plunger (310) is positioned on the upper support member (100) and includes a first contact portion (311) that can contact the terminal of the device under test and a second contact portion (315) formed on the lower side of the first contact portion that can contact the tightly wound portion of the coil spring (330).

[0051] The first contact portion (311) of the upper plunger (310) is configured to have a diameter smaller than the reduced diameter formed at the end of the upper support hole (110) of the upper support member (100) in a cylindrical shape, so that the upper side of the first contact portion can protrude toward the upper side of the upper support member (100). A plurality of crown-shaped tip portions (312) may be provided at the top of the first contact portion (311) to improve contact with the terminal (11) of the device under inspection (10). However, it is not limited thereto, and it is also possible to provide various shapes, such as a needle shape with a pointed end, a sphere, or a round shape, at the top of the first contact portion.

[0052] The second contact portion (315) of the upper plunger (310) is formed to have a larger diameter than the first contact portion (311) and also a larger diameter than the reduced diameter formed at the end of the upper support hole (110). Thus, the upper plunger (310) is not disengaged to the upper side of the upper support member (100) because the second contact portion (315) is restrained by the upper catch (120). The lower surface of the second contact portion (315) can be electrically connected to the lower plunger (320) by contacting the upper end of the tightly wound portion (331) of the coil spring (330). The lower surface of the second contact portion (315) can be formed in a flat disc shape so as to make stable contact with the tightly wound portion (331) of the coil spring (330).

[0053] The lower plunger (320) is disposed on the lower support member (200) and includes a lower flange portion (322), a rod portion (324) extending upward on the upper side of the lower flange portion, and a head portion (321) extending downward on the lower side of the lower flange portion.

[0054] The head portion (321) has a diameter smaller than the reduced diameter formed at the end of the lower support hole (210) of the lower support member (200), so it can protrude downward from the lower support member (200) and come into contact with the pad (21) of the tester.

[0055] The lower flange portion (322) is formed to have a larger diameter than the head portion (321) and also a larger diameter than the reduced diameter formed at the end of the lower support hole (210). Accordingly, the lower plunger (320) is not disengaged to the lower side of the lower support member (200) because the lower flange portion (322) is restrained by the lower catch (220).

[0056] The rod portion (324) has a diameter smaller than that of the lower flange portion (322) and is formed to extend upward in a cylindrical shape. The rod portion is a part that is inserted into the inner side of the coil spring (330) and slides with the inner side of the coil spring to make electrical contact.

[0057] The coil spring (330) includes a portion (331) that is tightly wound spirally on the upper side and a portion (332) that is relatively loosely wound below the tightly wound portion. The tightly wound portion (331) refers to a portion where the coils are wound at a high density so that they are in close contact with each other, and the loosely wound portion (332) refers to a portion where the coils are wound loosely at a low density so that they exert elastic force. Accordingly, the coil spring (330) can apply elastic force in the direction that the loosely wound portion pushes the lower plunger (320) and the upper plunger (310) upward and downward.

[0058] In this coil spring (330), the current follows a spiral path in the loosely wound portion (332), but in the tightly wound portion (331), a large area is in close contact, so a significant portion of the current can be conducted substantially linearly in the up and down direction.

[0059] The upper end of the tightly wound portion (331) of the coil spring (330) is positioned so that the second contact portion (315) of the upper plunger (310) can be contacted, the lower end of the coil spring (330) is positioned so that it can be contacted on the upper surface of the lower flange portion (322) of the lower plunger (320), and the rod portion (324) of the lower plunger (320) is fitted into the inside of the coil spring (330).

[0060] The outer diameter of the coil spring (330) is equal to or smaller than the diameter of the second contact portion (315) of the upper plunger (310). However, it is preferable that the diameter of the second contact portion (315) of the upper plunger (310) be larger than the outer diameter of the coil spring (330), so that the second contact portion (315) of the upper plunger (310) can make more stable contact with the upper end of the coil spring from the outside of the coil spring (330).

[0061] Additionally, the outer diameter of the coil spring (330) is equal to or slightly smaller than the diameter of the lower flange portion (322) of the lower plunger (320), and the inner diameter is slightly larger than the diameter of the rod portion (324) of the lower plunger (320). Since the inner diameter of the coil spring (330) is slightly larger than the diameter of the rod portion (324), the coil spring can be smoothly extended or compressed.

[0062] The tightly wound portion (331) of the coil spring (330) can be extended to a portion that overlaps with the end of the rod portion (324) in the pre-inspection state. When the coil spring (330) is compressed during the inspection process, the coil spring having an inner diameter slightly larger than the diameter of the rod portion is slightly bent or curved toward the support hole, so the rod portion (324) of the lower plunger (320) slides into contact with the inner side of the tightly wound portion (331) of the coil spring.

[0063] An inspection probe (300) that is elastically extended or compressed is positioned in an upper support member (100) and a lower support member (200), wherein an upper plunger (310) is located in the upper support hole (110) of the upper support member (100) and a lower plunger (320) is located in the lower support hole (210) of the lower support member (200). The upper plunger (310) and the lower plunger (320) are accommodated within the upper support hole (110) and the lower support hole (210) and are capable of reciprocating in the up and down direction according to the compression or extension of the coil spring (330), and the second contact portion (315) of the upper plunger (310) and the lower flange portion (322) of the lower plunger (320) are restrained by the upper catch (120) and the lower catch (220) of the support hole, respectively, so as to prevent detachment from the upper support member and the lower support member.

[0064] An inspection socket (1000) including such inspection probes (300) can be used to inspect a device to be inspected (10). The inspection socket (1000) is installed on a tester (20) such that a plurality of inspection probes (300) are connected to a pad (21) provided on the tester (20). During the electrical testing process for the device to be inspected (10), when the device to be inspected approaches the inspection socket and the terminal (11) of the device to be inspected presses against the inspection probe (300), the pressure applied to the upper plunger (310) is transmitted to the lower plunger (320) through the coil spring (330), and the loosely wound portion (332) of the coil spring is compressed. As the coil spring is compressed, the load portion (324) of the lower plunger (320) slides into contact with the inner side of the tightly wound portion (331) of the coil spring, thereby electrically connecting the terminal (11) of the device under test and the pad (21) of the tester through the test probe (300). That is, the test signal transmitted from the pad (21) of the tester is transmitted to the terminal (11) of the device under test through a signal transmission path that passes from the load portion (324) of the lower plunger (320) through the tightly wound portion (331) of the coil spring (330) to the upper plunger (310). At this time, the test signal generated by the tester (20) is transmitted to the device under test (10) through the test probe (300), so that an electrical test of the device under test can be performed.

[0065] Accordingly, in the test probe and test socket using the same according to the first embodiment of the present invention, since the upper plunger that repeatedly contacts the terminal of the device to be tested is provided as a separate component, only the upper plunger that has reached the end of its lifespan can be easily replaced, and the coil spring and lower plunger can be reused, thereby minimizing waste of parts and significantly reducing maintenance costs.

[0066] In addition, the inspection probe and test socket using the same according to the first embodiment of the present invention transmit a signal by the upper plunger contacting the top of the coil spring coupled with the lower plunger without fixing the upper plunger to the coil spring; thus, the signal transmission length is reduced by omitting the fixing part, thereby improving high-frequency transmission characteristics, and the manufacturing cost is reduced by shortening the length of the upper plunger, which uses expensive precious metal materials such as palladium alloy.

[0067] In addition, the inspection probe and test socket using the same according to the first embodiment of the present invention can be configured by simply joining the coil spring, upper plunger, and lower plunger without using an expensive barrel and without mechanical or elastic fixing processes such as crimp fitting, soldering, or welding to integrate them, so the structure is simple, manufacturing time is shortened, and manufacturing costs can be significantly reduced.

[0068] In addition, the test probe and test socket using the same according to the first embodiment of the present invention transmit the test signal through the tightly wound portion of the coil spring, so even if the number of windings in the loosely wound portion increases to obtain the necessary elastic force, the test signal can be transmitted without passing through the loosely wound portion, thereby reducing electrical resistance and improving the accuracy of the test, and preventing high frequency from flowing through the loosely wound portion, thereby improving high frequency transmission characteristics.

[0069] FIG. 6 is a drawing of an inspection probe according to a second embodiment of the present invention and an inspection socket including the same. The structure is identical to that of the inspection probe of the first embodiment, except that the lower plunger (320) has a boss portion (323) between the lower flange portion (322) and the rod portion (324).

[0070] In the following, even if the structure of the upper plunger, lower plunger, and coil spring is partially modified, the drawing reference numerals for the upper plunger, lower plunger, and coil spring shall be the same as those of the first embodiment.

[0071] The lower plunger (320) according to the second embodiment is composed of a lower flange portion (322), an upper boss portion (323), a rod portion (324) extending upward from the upper surface of the boss portion, and a head portion (321) extending downward from the lower surface of the lower flange portion.

[0072] The boss portion (323) is the part where the coil spring (330) is fixed and is formed in a cylindrical shape. It is formed to have a diameter slightly larger than the inner diameter of the coil spring (330) and a diameter smaller than the diameter of the lower flange portion (322). Since the inner diameter of the coil spring (330) is smaller than the outer diameter of the boss portion (323), the coil spring (330) can be firmly fixed to the lower plunger (320) by pressing and fitting the lower side of the coil spring (330) into the boss portion (323).

[0073] Accordingly, the inspection probe and test socket using the same according to the second embodiment of the present invention can fix the lower plunger and the coil spring as a single unit, so work productivity can be significantly improved when assembling the inspection probe to a support member.

[0074] FIG. 7 is a drawing of an inspection probe and an inspection socket including the same according to a third embodiment of the present invention. The structure is identical to that of the inspection probe of the first embodiment, except that the tightly wound portion (331) of the coil spring (330) has a portion (333) in which the diameter decreases at the upper portion, and the diameter of the rod portion (324) of the lower plunger (320) is thinner.

[0075] More specifically, the coil spring (330) according to the third embodiment has a portion (331) that is tightly wound spirally on the upper side and a portion (332) that is relatively loosely wound below the tightly wound portion, and a portion (333) that has a smaller diameter at the top of the tightly wound portion, such that the top of the tightly wound portion has a smaller diameter than the bottom.

[0076] Since the rod portion (324) of the lower plunger (320) must make sliding contact with the inner side of the portion (333) where the diameter decreases from the tightly wound portion (331) of the coil spring (330), the diameter of the rod portion (324) of the lower plunger (320) has a size slightly smaller than the inner diameter of the portion (333) where the diameter decreases from the tightly wound portion (331). The end of the rod portion (324) of the lower plunger (320) can be extended from the tightly wound portion (331) to the portion (333) where the diameter decreases in the pre-inspection state. When the coil spring (330) is compressed during the inspection process, the portion (333) of the coil spring where the diameter decreases, having an inner diameter slightly larger than the outer diameter of the rod portion, is slightly bent or curved toward the support hole, so the rod portion (324) of the lower plunger (320) can slide in contact with the inner side of the portion (333) where the diameter decreases from the tightly wound portion (331) of the coil spring.

[0077] In the third embodiment, the signal transmission path has a path that is transmitted from the load portion (324) of the lower plunger (320) through the diameter-decreasing portion (333) located at the top of the tightly wound portion (331) of the coil spring (330) to the upper plunger (310).

[0078] Accordingly, the test probe and test socket using the same according to the third embodiment of the present invention have the advantage of improving high-frequency signal transmission characteristics by increasing the range of choices for matching the impedance of the device under test, as the diameter of the load portion of the lower plunger can be made thinner, thereby reducing the capacitance proportional to the surface area and increasing the inductance proportional to the length and inversely proportional to the diameter to obtain a higher impedance.

[0079] In addition, the structure of the coil spring adopted in the inspection probe of the third embodiment can also be applied to the inspection probe of the second embodiment.

[0080] FIG. 8 is a drawing of an inspection probe according to a fourth embodiment of the present invention and an inspection socket including the same. The structure is identical to that of the inspection probe of the first embodiment, except that the upper plunger (310) has a hemispherical third contact portion (317).

[0081] More specifically, the upper plunger (310) according to the fourth embodiment comprises a first contact portion (311) capable of contacting a terminal of a device under test, a second contact portion (315) formed on the lower side of the first contact portion and capable of contacting the upper end of a tightly wound portion (331) of a coil spring (330), and a third contact portion (317) formed on the lower side of the second contact portion (315) and capable of contacting the inner side of the tightly wound portion (331).

[0082] The third contact portion (317) of the upper plunger (310) is located at the center of the second contact portion (315) and has a hemispherical shape. Since the diameter of the third contact portion is equal to or slightly larger than the inner diameter of the tightly wound portion of the coil spring (330), the third contact portion (317) can be inserted into the coil spring and come into contact with the inner side of the tightly wound portion.

[0083] Accordingly, the inspection probe and test socket using the same according to the fourth embodiment of the present invention can improve the accuracy of the inspection by reducing the overall resistance of the inspection probe, as the contact area is increased because the upper plunger can contact the entire inner row of the upper winding of the tightly wound portion of the coil spring.

[0084] In addition, the structure of the upper plunger adopted in the inspection probe of the fourth embodiment can also be applied to the inspection probes of the second and third embodiments.

[0085] FIG. 9 is a drawing of an inspection probe according to the fifth embodiment of the present invention and an inspection socket including the same. The structure is identical to that of the inspection probe of the first embodiment, except that the second contact portion (315) of the upper plunger (310) is composed of an upper flange portion (313) with a large diameter and a flange extension portion (314) with a small diameter.

[0086] More specifically, the upper plunger (310) according to the fifth embodiment is provided with a first contact portion (311) that can contact a terminal of a device under test, and a second contact portion (315) formed on the lower side of the first contact portion and capable of contacting the upper end of a tightly wound portion (331) of a coil spring (330), wherein the second contact portion (315) is composed of an upper flange portion (313) with a large diameter and a flange extension portion (314) with a small diameter.

[0087] The second contact portion (317) of the upper plunger (310) is composed of an upper flange portion (313) with a large diameter and a flange extension portion (314) formed on the lower side of the upper flange and having a smaller diameter than the upper flange portion (313), and the diameter of the flange extension portion (314) is larger than the inner diameter of the coil spring (330). Therefore, at the second contact portion (315), the lower surface of the flange extension portion (314) can come into contact with the upper end of the tightly wound portion (331) of the coil spring (330).

[0088] Accordingly, the inspection probe and test socket using the same according to the fifth embodiment of the present invention can form a long inspection probe by utilizing the pre-fabricated coil spring and lower plunger as they are and fabricating a long upper plunger as a flange extension when it is necessary to place a long inspection probe corresponding to a large warpage of the device under inspection or to increase the thickness of the test socket and thus the usability of the inspection probe can be greatly increased.

[0089] In addition, the structure of the upper plunger adopted in the inspection probe of the fifth embodiment can also be applied to the inspection probes of the second, third, and fourth embodiments. However, it should be noted that in the case of the inspection probe of the fourth embodiment, the flange extension is installed between the second contact portion and the hemispherical third contact portion.

[0090] FIG. 10 is a drawing of an inspection probe and an inspection socket including the same according to the sixth embodiment of the present invention. The structure is identical to that of the inspection probe of the first embodiment, except that the upper plunger (310) has a guide portion (319) that extends downward on the lower surface of the second contact portion (315).

[0091] More specifically, the upper plunger (310) according to the sixth embodiment has a first contact portion (311) that can contact a terminal of a device to be tested, and a second contact portion (315) formed on the lower side of the first contact portion that can contact the upper end of a tightly wound portion (331) of a coil spring (330), and a guide portion (319) formed on the lower side of the second contact portion (315) that extends downward and is inserted into the inner side of the tightly wound portion (331) of the coil spring (330).

[0092] The guide portion (319) of the upper plunger (310) has a diameter smaller than the inner diameter of the tightly wound portion (331) of the coil spring (330). Therefore, as the guide portion (319) of the upper plunger (310) is inserted into the tightly wound portion of the coil spring, the second contact portion (315) and the coil spring (330) can be positioned in the correct position, and in this state, the second contact portion (315) can come into contact with the top of the tightly wound portion.

[0093] Accordingly, the inspection probe and test socket using the same according to the sixth embodiment of the present invention can position a tightly wound portion of the coil spring at the center of the second contact portion of the upper plunger, so the compression operation of the coil spring can be stably maintained.

[0094] Furthermore, the structure of the upper plunger adopted in the inspection probe of the 6th embodiment can also be applied to the inspection probes of the 2nd, 3rd, 4th, and 5th embodiments. However, it should be noted that in the case of the inspection probe of the 4th embodiment, the guide portion is installed below the flange extension portion, and in the case of the inspection probe of the 5th embodiment, the guide portion is installed below the third contact portion.

[0095] FIG. 11 is a drawing of an inspection probe according to the seventh embodiment of the present invention and an inspection socket including the same. The structure is identical to that of the inspection probe of the first embodiment, except that there is a tightly wound portion (335) on the lower side of the coil spring (330).

[0096] More specifically, the coil spring (330) according to the seventh embodiment has a spirally wound portion (331, 335) on the upper and lower sides, and a relatively loosely wound portion (332) between the tightly wound portions (331, 335) on the upper and lower sides. The tightly wound portions (331, 335) on the upper and lower sides may be provided symmetrically with respect to each other.

[0097] In this way, by providing a densely wound portion (331) on the upper side of the coil spring and a densely wound portion (335) on the lower side of the coil spring symmetrically with each other, the directionality of the coil spring does not need to be considered during the automatic alignment process using vibration and a jig during the assembly process of the inspection probe, thus making alignment easier and improving assembly productivity.

[0098] In addition, the structure of the coil spring adopted in the inspection probe of the 7th embodiment can also be applied to the inspection probes of the 2nd, 3rd, 4th, 5th, and 6th embodiments.

[0099] FIG. 12 is a drawing of an inspection probe and an inspection socket including the same according to the eighth embodiment of the present invention, and FIG. 13 is a drawing showing a tubular spring. The structure is identical to that of the inspection probe of the first embodiment except that a tubular spring (340) is used instead of a coil spring (330).

[0100] More specifically, the tubular spring (340) according to the eighth embodiment is in the shape of a cylinder, and a spiral spring portion (343) formed by cutting into a spiral shape is provided on the lower side, and an uncut cylindrical connecting portion (341) is provided on the upper side. The spiral spring portion (343) is a part that undergoes elastic deformation during inspection of the device under inspection.

[0101] A tubular spring (340) can be manufactured by forming a spiral spring portion (343) that expands or contracts in the vertical direction by forming a spiral-shaped cut portion on the lower side, excluding the upper connecting portion (341) of a cylindrical body made of a conductive material. The elastic force of the tubular spring can be changed by appropriately adjusting the width or length of the spiral-shaped cut portion.

[0102] An inspection probe using a tubular spring according to the eighth embodiment can electrically connect the pad of a tester and the terminal of a device to be inspected by configuring the second contact portion (315) of an upper plunger (310) to contact the upper end of the connection portion (341) of the tubular spring (340), and the lower plunger (320) fitted to the lower side of the tubular spring (340) to contact the inner side of the connection portion (341) of the tubular spring (340) so as to be slidably contact.

[0103] In addition, it is possible to apply the structure of the lower plunger adopted in the second embodiment to the eighth embodiment. By forming the outer diameter of the boss portion (323) of the lower plunger to be slightly larger than the inner diameter of the tubular spring (340) and compressing the lower side of the tubular spring (340) into the boss portion (323), the tubular spring can be firmly fixed to the lower plunger, thereby improving work productivity when assembling the inspection probe to the support member.

[0104] Coil springs using conventional coils depend on the diameter of the coil itself, making it difficult to form a coil with a diameter smaller than about four times the coil diameter. Consequently, it was extremely difficult to manufacture coil springs with an outer diameter of 100 μm or less, and even if manufactured, there were problems with assembly and manufacturing costs, which made it impractical to apply them to inspection sockets equipped with 2 to 4,000 inspection probes due to high costs.

[0105] However, the inspection probe and test socket using the same according to the eighth embodiment of the present invention can manufacture an inspection probe with a thinner diameter by using a tubular spring that can be made thinner instead of a coil spring, thereby easily accommodating devices under inspection with fine pitch, and since the inspection probe with a thinner diameter has a greater potential to increase impedance, it has the effect of improving high-frequency signal transmission characteristics.

[0106] Furthermore, it is possible to apply the structure of the upper plunger adopted in the inspection probes of the 4th, 5th, and 6th embodiments as is to the structure of the tubular spring adopted in the inspection probe of the 8th embodiment. In addition, it is possible to have a structure similar to the inspection probe of the 3rd embodiment by forming a portion with a decreasing diameter at the top of the connection part of the tubular spring, and it is also possible to have a structure similar to the inspection probe of the 7th embodiment by adopting a tubular spring equipped with connection parts on both the upper and lower sides.

[0107] FIGS. 14 and 15 are drawings illustrating a first modified example of a test socket using an inspection probe according to the first to eighth embodiments. In the drawings, the inspection probe of the second embodiment is used as an example, but it should be noted that the inspection probe according to the first, third to eighth embodiments can also be used in the same way.

[0108] As shown in FIGS. 14 and 15, a lower cover (150) is additionally provided on the lower side of the upper support member (100), having a lower cover hole (151) formed with a diameter smaller than the diameter of the second contact portion (315) and larger than the outer diameter of the coil spring (330).

[0109] The bottom cover (150) is connected to the lower side of the upper support member (100) by means of a screw connection or the like, and the upper support member (100) to which the bottom cover (150) is connected is connected to the lower support member (200) by means of a screw connection or the like. Therefore, when the upper support member (100) is separated from the lower support member (200), the upper support member (100) is separated with the bottom cover (150) connected to the lower side of the upper support member (100).

[0110] With the lower cover (150) attached to the lower side of the upper support member (100), the diameter of the second contact portion (315) of the upper plunger (310) is formed to be larger than the reduced diameter formed at the end of the upper support hole (110) and the diameter of the lower cover hole (151). Therefore, when the lower cover (150) is attached to the lower side of the upper support member (100), the upper plunger (310) is accommodated without being detached.

[0111] With the upper support member (100) to which the lower cover (150) is attached turned upside down, the lower cover (150) can be removed, and the upper plunger that has reached the end of its lifespan can be easily replaced. In addition, if multiple upper plungers are damaged, the entire upper support member (100) to which the lower cover (150) containing the upper plungers is attached can be replaced with a new one, so rapid replacement is possible, replacement costs are reduced, and maintenance of the Automated Test Equipment (ATE) equipment connected to the inspection socket can be made easier.

[0112] FIGS. 16 and 17 are drawings showing a second variant of a test socket using an inspection probe according to the first to eighth embodiments. The structure is identical to that of the first variant of the test socket, except that an upper cover (250) is additionally provided on the upper side of the lower support member (200).

[0113] As shown in FIGS. 16 and 17, an upper cover (250) is provided on the upper side of the lower support member (200), having an upper cover hole (251) formed with a diameter smaller than the diameter of the lower flange portion (322) and larger than the outer diameter of the coil spring (330).

[0114] The upper cover (250) is connected to the upper side of the lower support member (200) by means of a screw connection or the like, and the lower support member (200) to which the upper cover (250) is connected is connected to the upper support member (100) to which the lower cover (150) is connected by means of a screw connection or the like. Therefore, when the lower support member (200) is separated from the upper support member (100), the lower support member (200) can be separated with the upper cover (250) connected to the upper side of the lower support member (200).

[0115] With the upper cover (250) attached to the upper side of the lower support member (200), the diameter of the lower flange portion (322) of the lower plunger (320) is formed to be larger than the reduced diameter formed at the end of the lower support hole (210) and the diameter of the upper cover hole (251), so that the lower plunger (320) is accommodated without being detached when the upper cover (250) is attached to the upper side of the lower support member (200).

[0116] Therefore, since the lower plunger and the coil spring or tubular spring are accommodated in the lower support member and the upper plunger in the upper support member without becoming detached, there is an advantage in that the assembly and handling of the test socket become convenient.

[0117] Although the present invention has been illustrated and described above in relation to preferred embodiments for illustrating the principles of the invention, the invention is not limited to the configuration and operation as illustrated and described. Rather, those skilled in the art will understand that numerous changes and modifications to the invention are possible without departing from the spirit and scope of the appended claims. Explanation of the symbols

[0118] 10: Blood test device 11: Terminal 20: Tester 21: Pad 100: Upper support member 110: Upper support hole 120: Upper catch 150: Lower cover 151: Bottom cover hole 200: Lower support member 210: Lower support hole 220: Lower locking tab 250: Top cover 251: Top cover hole 300: Inspection probe 310: Upper plunger 311: First contact part 315: Second contact part 317: Third contact part 319: Guide part 320: Lower plunger 321: Head section 322: Lower flange section 323: Boss section 324: Load section 330: Coil spring 331: Tightly wound section 332: Loosely wound section 340: Tubular spring

Claims

Claim 1 An elastic inspection probe disposed between a device to be inspected having a terminal and a tester having a pad, wherein the upper support member and the lower support member each have a support hole formed at a position corresponding to the terminal, and the probe is disposed to be inserted into the support hole to prevent detachment, wherein the inspection probe comprises an upper plunger capable of contacting the terminal, a lower plunger capable of contacting the pad, and a coil spring having a portion that is tightly wound on the upper side and has the lower plunger fitted thereon, and wherein the upper plunger is a separate part that is not fixed to the coil spring and is separated, and comprises a first contact portion capable of contacting the terminal and a second contact portion capable of contacting the upper end of the tightly wound portion, wherein in the coil spring, the upper end of the tightly wound portion contacts the second contact portion, and the inner side of the tightly wound portion contacts the lower plunger so as to be slidably contact. Claim 2 In claim 1, the inspection probe is characterized in that the lower plunger has a boss portion with a diameter larger than the inner diameter of the coil spring, and the coil spring is fitted and fixed to the boss portion. Claim 3 An inspection probe according to claim 1 or 2, characterized in that the upper portion of the tightly wound part has a smaller diameter than the lower portion. Claim 4 An inspection probe according to claim 1 or 2, wherein the upper plunger is provided with a hemispherical third contact portion below the second contact portion, and the third contact portion contacts the inner side of the tightly wound portion. Claim 5 An inspection probe according to claim 1 or 2, wherein the second contact portion of the upper plunger comprises an upper flange portion and a flange extension portion formed below the upper flange portion, and the flange extension portion contacts the upper end of the tightly wound portion. Claim 6 An inspection probe according to claim 1 or 2, wherein the upper plunger has a guide portion extending downward from the second contact portion, and the guide portion is inserted into the inner side of the tightly wound portion. Claim 7 An inspection probe according to claim 1 or 2, characterized in that a densely wound portion is symmetrically provided on the lower side of the coil spring as well. Claim 8 An elastic inspection probe is disposed between a device to be inspected having a terminal and a tester having a pad, wherein the upper support member and the lower support member each have a support hole formed at a position corresponding to the terminal, and the probe is disposed to be inserted into the support hole to prevent detachment, wherein the inspection probe comprises an upper plunger capable of contacting the terminal, a lower plunger capable of contacting the pad, and a cylindrical tubular spring having a spiral spring portion provided on the lower side and a connection portion provided on the upper side, wherein the lower plunger is inserted into the lower side of the tubular spring, and the upper plunger is a separate part that is not fixed to the tubular spring but is separated, and comprises a first contact portion capable of contacting the terminal and a second contact portion capable of contacting the upper end of the connection portion of the tubular spring, wherein in the tubular spring, the upper end of the connection portion contacts the second contact portion, and the inner side of the connection portion contacts the lower plunger so as to be slidably contacted. Claim 9 A test socket for performing an electrical test on a device to be tested by connecting a terminal of the device to be tested to a pad of a tester that generates a test signal, comprising an upper support member and a lower support member disposed between the device to be tested and the tester, each having a support hole formed at a position corresponding to the terminal, and an elastic test probe disposed to be inserted into each of the support holes to prevent detachment, wherein the test probe comprises an upper plunger capable of contacting the terminal, a lower plunger capable of contacting the pad, and a coil spring having a tightly wound portion on its upper side and the lower plunger fitted and fixed thereto on its lower side, wherein the upper plunger is a separate component separated from the coil spring and is provided with a first contact portion capable of contacting the terminal and a second contact portion capable of contacting the upper end of the tightly wound portion, wherein in the coil spring, the upper end of the tightly wound portion contacts the second contact portion, and the inner side of the tightly wound portion contacts the lower plunger so as to be slidably contacted. An inspection socket characterized by the following. Claim 10 In claim 9, the inspection socket is characterized in that a lower cover is provided on the lower side of the upper support member, the lower cover having a diameter smaller than the diameter of the second contact portion and larger than the outer diameter of the coil spring. Claim 11 An inspection socket according to claim 9 or 10, wherein the lower plunger comprises a head portion in contact with the pad, a lower flange portion in contact with the coil spring, and a rod portion capable of contacting the inner side of the tightly wound portion, and the upper side of the lower support member is provided with an upper cover having an upper cover hole formed therein having a diameter smaller than the diameter of the lower flange portion and a diameter larger than the outer diameter of the coil spring.

Images