Low-leakage double-signal test probe

Abstract

The utility model discloses a low-leakage double-signal test probe, which comprises a probe arm, a double-tip coaxial probe and a pair of connectors are regularly mounted on the probe arm, the pair of connectors comprises a Force end connector and a Sense end connector, two tips at the front end of the double-tip coaxial probe are bent towards each other and are close to each other but not in contact to form a double-tip structure, and the Force end connector is connected with the Sense end connector. And two needle rods at the rear end of the connector are electrically connected to the Force end connector and the Sense end connector respectively. According to the utility model, through the designed double-needle-point structure, the contact area between the needle point and the PAD can be increased, so that the contact resistance between the needle point and the PAD is effectively reduced, and the parasitic resistance of the probe and the contact resistance between the needle point and the PAD are perfectly eliminated. Meanwhile, the needle point only needs to be in effective contact with the PAD, the requirement for the needle inserting depth is low, damage to the PAD is small, the service life of the PAD can be remarkably prolonged, and the accuracy of a test result can still be guaranteed after repeated testing.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor test probes, in particular to a low leakage dual-signal test probe. Background Art

[0002] As semiconductor process technology becomes more and more advanced, the RDS (Drain-Source Resistance) of transistors is getting smaller and smaller, and the parasitic resistance of the test device itself has an increasingly greater impact on the test results. Traditional test methods and test devices can no longer meet the requirements for the accuracy of test results.

[0003] As we all know, the Kelvin test method is an important method for signal measurement in electronic circuits. It uses four wires to transmit current and measure voltage respectively, which can effectively eliminate the interference of wire parasitic resistance and contact resistance on the measurement results. The current development trend of integrated circuits: the device size is getting smaller and smaller, the functions are increasing, and the higher integration leads to smaller chip area, and the required test devices, especially PAD size, are getting smaller and smaller. Due to the limitation that the volume of the probe cannot be reduced indefinitely, the Kelvin test method is difficult to implement perfectly, and the parasitic resistance of the test probe and the contact resistance with the PAD are difficult to effectively eliminate.

[0004] In traditional probe testing, in order to reduce the contact resistance between the needle tip and the PAD, the needle needs to be inserted very deep, which causes great damage to the PAD and reduces the test life of the PAD. After more tests, a greater contact resistance will be generated, which further affects the accuracy of the test results. Utility Model Content

[0005] The utility model provides a small-volume, low-leakage dual-signal test probe that can perfectly implement the Kelvin test method, thereby perfectly eliminating the parasitic resistance of the probe and the contact resistance with the PAD, and effectively improving the accuracy of the test result.

[0006] The technical solution adopted by the utility model to solve its technical problems is:

[0007] A low leakage dual signal test probe comprises a probe arm, on which a double-tip coaxial probe and a pair of connectors are regularly mounted, the pair of connectors comprising a Force end connector and a Sense end connector, the two needle tips at the front end of the double-tip coaxial probe are bent towards each other and tightly close to each other but not in contact to form a double-tip structure, and the two needle rods at the rear end are electrically connected to the Force end connector and the Sense end connector respectively.

[0008] Furthermore, in one embodiment, the double-tip coaxial probe includes two coaxial probes arranged in parallel, namely a first coaxial probe and a second coaxial probe, the first coaxial probe and the second coaxial probe each including a separate inner core, a protective layer and a high dielectric constant material layer arranged between the inner core and the protective layer, the inner core includes the needle rod and the needle tip, the high dielectric constant material layer is sleeved on the inner core and exposes the rear end of the needle rod and the needle tip at the front end of the needle rod, and the protective layer is sleeved on the high dielectric constant material layer; the rear end of the needle rod extends out of the rear end of the high dielectric constant material layer to form a connection end for electrically connecting the Force end connector or the Sense end connector, and the needle tip extends out of the front end of the high dielectric constant material layer to contact the PAD on the wafer for needle testing; the needle tips at the front ends of the first coaxial probe and the second coaxial probe are bent toward each other and tightly close to form a double needle tip structure.

[0009] Furthermore, in another embodiment, the double-tip coaxial probe is an integrated double-tip coaxial probe, including a pair of inner cores, a protective layer and a high dielectric constant material layer arranged between the pair of inner cores and the protective layer, the high dielectric constant material layer is an integrated structure sleeved on the pair of inner cores to wrap the pair of inner cores and expose the needle rods at the rear end of the pair of inner cores and the needle tips at the front end, and the protective layer is also an integrated structure sleeved on the high dielectric constant material layer to wrap the high dielectric constant material layer; the needle tips at the front end of the pair of inner cores are bent toward each other and tightly closed to form a double-tip structure.

[0010] Furthermore, a bending portion that is bent obliquely downward is provided at the front end of the double-tip coaxial probe, and the bending angle of the bending portion is 30°-90°.

[0011] Preferably, the distance between the needle tips at the front end of the double-tip coaxial probe is 25 μm-50 μm.

[0012] Furthermore, the upper end of the probe mounting arm is regularly provided with a pair of connector mounting slots for mounting the Force end connector and the Sense end connector, and the lower end of the probe mounting arm is regularly provided with a cavity to form a connecting slot, and the pair of connector mounting slots are connected with the connecting slot, so as to facilitate the electrical connection between the double-tip coaxial probe and the Force end connector and the Sense end connector; the front end of the probe mounting arm is regularly provided with a clamping opening, and the clamping opening horizontally cuts the front end of the probe mounting arm backward to form an incision and a clamping plate below the incision, and the front end of the clamping opening is also regularly provided with a probe mounting hole for mounting the double-tip coaxial probe, and the probe mounting hole is also connected with the connecting slot, and the double-tip coaxial probe is inserted from the probe mounting hole into the connecting slot to be electrically connected with the Force end connector and the Sense end connector.

[0013] Furthermore, a plurality of fastener fixing holes are regularly arranged on the clamping plate, and threaded holes cooperating with fasteners such as bolts are vertically arranged in the probe mounting arm above the fastener fixing holes. The clamping plate cooperates with the threaded holes through fasteners such as bolts, is tightened to clamp and fix the double-tip coaxial probe, and is loosened to release the double-tip coaxial probe.

[0014] The beneficial effects of the utility model are:

[0015] 1. The utility model has a dual-tip dual-signal structure designed to make the short point on the PAD through the Kelvin measurement method, eliminating the parasitic resistance of the probe and the contact resistance between the needle tip and the PAD, thereby perfectly eliminating the parasitic resistance of the probe and the contact resistance between the needle tip and the PAD. At the same time, the needle tip only needs to effectively contact the PAD, which has a small requirement for the needle insertion depth and is less destructive to the PAD, which can significantly increase the service life of the PAD. Repeated tests can still ensure the accuracy of the test results.

[0016] 2. The utility model provides a high dielectric constant material layer as an inner lining between the inner core and the protective layer, thereby providing advanced characteristic analysis and reliability testing fA-level measurement capabilities within a temperature range of -60°C to 150°C, effectively ensuring the low leakage performance of the probe and meeting the use in low leakage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the utility model;

[0018] Figure 2 for Figure 1 The structural diagram from an upward perspective;

[0019] Figure 3 for Figure 1Right view of;

[0020] Figure 4 for Figure 3 Sectional view in the AA direction;

[0021] The markings in the figure are:

[0022] 1. Probe mounting arm, 2. Dual-tip coaxial probe, 3. Force end connector, 4. Sense end connector;

[0023] 101. Clamping port, 102. Clamping plate, 103. Probe mounting hole, 104. Connecting groove, 105. Fastener fixing hole, 21. First coaxial probe, 22. Second coaxial probe, 201. Inner core, 202. High dielectric constant material layer, 203. Protective layer, 2101. Needle rod, 2102. Needle tip, 2103. Bend. DETAILED DESCRIPTION

[0024] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0026] like Figure 1-4 As shown, the utility model discloses a low leakage dual signal test probe, comprising a probe mounting arm 1, a dual-tip coaxial probe 2 and a pair of connectors. The pair of connectors comprises a force end connector 3 and a sense end connector 4. The probe mounting arm 1 is used to mount the dual-tip coaxial probe 2, the force end connector 3 and the sense end connector 4.

[0027] Furthermore, the double-tip coaxial probe 2 is installed at the front end of the probe mounting arm 1, including a double-tip structure at the front end, and the double-tip structure contacts the PAD on the wafer test device to perform wafer needle testing. The force end connector 3 and the sense end connector 4 are installed at the upper end of the probe mounting arm 1 and extend into the probe mounting arm 1 to be electrically connected to the double-tip coaxial probe 2.

[0028] Further, such as Figure 3 and Figure 4 As shown, it is a specific structural diagram of the double-tip coaxial probe 2. In one embodiment, the double-tip coaxial probe 2 adopts an independent design, including two coaxial probes arranged in parallel, including a first coaxial probe 21 and a second coaxial probe 22, the tips of the two coaxial probes are bent towards each other and are infinitely close to each other but do not touch each other to form a double-tip structure, and the distance between the tips of the two coaxial probes is less than 50μm. Preferably, the distance between the tips of the two coaxial probes is 25μm-50μm.

[0029] Among them, Figure 4 As shown, the first coaxial probe 21 and the second coaxial probe 22 each include a separate inner core 201, a protective layer 203, and a high dielectric constant material layer 202 disposed between the inner core and the protective layer. The inner core 201 is an electrode material with conductive properties, including a needle rod 2011 and a needle tip 2012 at the front end of the needle rod. The high dielectric constant material layer 202 is sleeved on the inner core 201, and the rear end and front end of the needle rod 2011 are exposed. The rear end of the needle rod 2011 extends out of the rear end of the high dielectric constant material layer 202 to form a connection end for electrically connecting the Force end connector 3 or the Sense end connector 4; the needle tip 2012 extends out of the front end of the high dielectric constant material layer 202 to contact the PAD on the wafer for needle piercing testing. The protective layer 203 is sleeved on the high dielectric constant material layer 202, on the one hand, to protect the high dielectric constant material layer and the inner core, and on the other hand, in the electrical testing of semiconductors, to protect electrical signals to reduce leakage.

[0030] The first coaxial probe and the second coaxial probe both adopt a coaxial structure. The outer protective layer is connected to the Guard signal, the inner core is connected to the Signal signal, and the middle is filled with high dielectric constant material, which can effectively ensure the low leakage performance of the probe.

[0031] Furthermore, in another embodiment, the double-tip coaxial probe 2 adopts an integrated design, including a pair of inner cores 201, a protective layer 203 and a high dielectric constant material layer 202 disposed between the pair of inner cores and the protective layer. The high dielectric constant material layer 202 is an integrated structure that wraps the pair of inner cores 201, and the protective layer is also an integrated structure that is sleeved outside the high dielectric constant material layer and wraps the high dielectric constant material layer.

[0032] like Figure 3 As shown, the tips of the first coaxial probe 21 and the second coaxial probe 22 extending out of the high dielectric constant material layer are bent toward each other but close to each other without contacting each other to form a double tip structure. The double tip structure can perfectly eliminate the parasitic resistance of the probe and the contact resistance between the tip and the PAD. By using the Kelvin measurement method, the short point is made on the PAD. The double tip structure of the utility model can eliminate the parasitic resistance of the probe and the contact resistance between the tip and the PAD. At the same time, the tip only needs to be in effective contact with the PAD, which has a small requirement for the depth of the needle and is less destructive to the PAD. It can significantly improve the service life of the PAD, and the accuracy of the test results can still be guaranteed after repeated tests.

[0033] In the Kelvin measurement method, one set of needle tips measures the current passing through the PAD, and the other set of needle tips measures the voltage between the short-circuit points of the double needle tips. Because the short-circuit point is the PAD, and the contact resistance and parasitic resistance are behind the PAD. Therefore, through the test of the double needle tip dual signal test probe of the utility model, the parasitic resistance and contact resistance can be directly ignored.

[0034] like Figure 4 As shown, in one embodiment, in order to facilitate the needle test, the front end of the needle rod 2011 is provided with a bent portion 2013 that is tilted downward, and the downward bending angle is 30°-90°. Therefore, in actual use, the needle rod 2011 is horizontally mounted to the front end of the probe mounting arm 1, and the needle tip 2012 at the front end of the needle rod is naturally tilted and bent downward, which is convenient for needle testing with the wafer below, and on the other hand, the needle rod 2011 and the bent portion 2013 can provide good elasticity for the needle tip 2012 at the front end, so that soft contact between the needle tip and the PAD can be achieved, further reducing the damage of the needle tip to the PAD.

[0035] Further, such as Figure 1 and Figure 2 As shown, the upper end of the probe mounting arm 1 is regularly provided with a pair of connector mounting notches, and a pair of connectors are respectively installed to form a force end connector 3 and a sense end connector 4. The lower end of the probe mounting arm 1 is provided with a chamber to form a connection groove 104, and the connector mounting notches at the upper end of the probe mounting arm are connected to the connection groove 104, so as to facilitate the electrical connection between the force end connector 3 and the sense end connector 4 and the double-tip coaxial probe 1.

[0036] Furthermore, the front end of the probe mounting arm 1 is regularly provided with a clamping opening 101, which cuts the front end of the probe mounting arm 1 horizontally backward to form an incision and a clamping plate 102 below the incision. Among them, a probe mounting hole 103 for mounting the double-tip coaxial probe 2 is also regularly provided at the middle position of the front end of the clamping opening 101, and the probe mounting hole 103 is also connected to the connection groove 104, so as to facilitate the double-tip coaxial probe 2 to be inserted from the probe mounting hole 103 into the connection groove 104 to be electrically connected with the force end connector 3 and the sense end connector 4.

[0037] Furthermore, a plurality of fastener fixing holes 105 are regularly arranged on the clamping plate 102, and threaded holes cooperating with fasteners such as bolts are vertically arranged in the probe mounting arm above the fastener fixing holes 105, so as to facilitate fasteners such as bolts to pass through the fastener fixing holes 105 and cooperate with the threaded holes below them to tighten or release the clamping plate 102.

[0038] like Figure 2 As shown, the double-tip coaxial probe 2 is inserted from the probe mounting hole 103 into the connection slot 104, and is electrically connected to the Force end connector and the Sense end connector to form a dual signal test. In one embodiment, the inner core of the first coaxial probe 21 is electrically connected to the Force end connector 3, and the inner core of the second coaxial probe 22 is electrically connected to the Sense end connector 4.

[0039] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low leakage dual signal test probe, comprising a probe mounting arm, characterized in that: A double-tip coaxial probe and a pair of connectors are regularly installed on the probe mounting arm. The pair of connectors includes a Force end connector and a Sense end connector. The two needle tips at the front end of the double-tip coaxial probe are bent toward each other and tightly close to each other but not in contact to form a double-tip structure, and the two needle rods at the rear end are electrically connected to the Force end connector and the Sense end connector respectively.

2. The low leakage dual signal test probe according to claim 1, characterized in that: The double-tip coaxial probe includes two coaxial probes arranged in parallel, which are a first coaxial probe and a second coaxial probe respectively. The first coaxial probe and the second coaxial probe each include an inner core, a protective layer and a high dielectric constant material layer arranged between the inner core and the protective layer. The inner core includes the needle rod and the needle tip. The high dielectric constant material layer is sleeved on the inner core and exposes the rear end of the needle rod and the needle tip at the front end of the needle rod. The protective layer is sleeved on the high dielectric constant material layer. The rear end of the needle rod extends out of the rear end of the high dielectric constant material layer to form a connection end for electrically connecting the Force end connector or the Sense end connector. The needle tip extends out of the front end of the high dielectric constant material layer to contact the PAD on the wafer for needle piercing test. The needle tips at the front ends of the first coaxial probe and the second coaxial probe are bent toward each other and tightly close to form a double-tip structure.

3. The low leakage dual signal test probe according to claim 1, characterized in that: The double-tip coaxial probe is an integrated double-tip coaxial probe, comprising a pair of inner cores, a protective layer and a high dielectric constant material layer arranged between the pair of inner cores and the protective layer. The high dielectric constant material layer is an integrated structure sleeved on the pair of inner cores to wrap the pair of inner cores and expose the needle rods at the rear ends of the pair of inner cores and the needle tips at the front ends. The protective layer is also an integrated structure sleeved on the high dielectric constant material layer to wrap the high dielectric constant material layer; the needle tips at the front ends of the pair of inner cores are bent toward each other and tightly close to form a double-tip structure.

4. The low leakage dual signal test probe according to claim 2 or 3, characterized in that: A bending portion that bends downwardly is arranged at the front end of the double-needle-tip coaxial probe, and the bending angle of the bending portion is 30°-90°.

5. The low leakage dual signal test probe according to any one of claims 1 to 3, characterized in that: The distance between the needle tips at the front end of the double-tip coaxial probe is 25 μm-50 μm.

6. The low leakage dual signal test probe as claimed in claim 4, characterized in that: The upper end of the probe mounting arm is regularly provided with a pair of connector mounting slots for mounting the Force end connector and the Sense end connector, and the lower end of the probe mounting arm is regularly provided with a cavity to form a connecting slot, and the pair of connector mounting slots are connected with the connecting slot, so as to facilitate the electrical connection between the double-tip coaxial probe and the Force end connector and the Sense end connector; the front end of the probe mounting arm is regularly provided with a clamping opening, and the clamping opening horizontally cuts the front end of the probe mounting arm backward to form an incision and a clamping plate below the incision, and the front end of the clamping opening is also regularly provided with a probe mounting hole for mounting the double-tip coaxial probe, and the probe mounting hole is also connected with the connecting slot, and the double-tip coaxial probe is inserted from the probe mounting hole into the connecting slot to be electrically connected with the Force end connector and the Sense end connector.

7. The low leakage dual signal test probe as claimed in claim 6, characterized in that: The clamping plate is also regularly provided with a plurality of fastener fixing holes, and a threaded hole cooperating with a bolt is vertically provided in the probe mounting arm above the fastener fixing hole. The clamping plate cooperates with the threaded hole through the bolt, and is tightened to clamp and fix the double-tip coaxial probe, and loosened to release the double-tip coaxial probe.

Images