Superhard alloy head test piece with ultra-small Kelvin gap

Abstract

The invention relates to the technical field of test pieces, in particular to a superhard alloy head test piece with an ultra-small Kelvin gap. The test piece comprises two metal test pieces, and superhard alloy heads are embedded in the two metal test pieces. Through the isolation design of the 0.015 mm ultra-small Kelvin gap and the insulating layer, current and voltage transmission paths can be effectively separated, interference of wire resistance and contact resistance on a measurement result can be accurately eliminated, the high-precision requirement of ultra-small pins in a precision test can be met, the ultra-hard alloy head is embedded in the special-shaped groove of the metal test piece, and the precision of the ultra-hard alloy head is improved. By utilizing the high hardness of more than 70 HRC and the high temperature resistance of more than 1000 DEG C, the ablation loss of the metal test piece in the use process is obviously reduced, and even in a high-frequency test or a high-temperature environment, the stable contact between the first contact head and the second contact head and a tested object can be ensured, the reliability of the contact performance is maintained, and the service life of the test piece is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of test pieces, in particular to a super-hard alloy head test piece with an ultra-small Kelvin gap. Background Art

[0002] When semiconductor components are produced on an assembly line, performance parameters often need to be tested and separated. Test strips play an important role in connecting test materials and test machines. Whether the performance of the test strips is good will directly affect production efficiency, product quality and production costs.

[0003] In the R&D and production of semiconductors, microelectronics, and precision electronic devices, high-precision testing of the electrical parameters of ultra-small pins is critical to ensuring product performance and reliability. Traditional testing methods use two-wire measurement, where current and voltage signals share the same transmission line. Wire resistance and contact resistance significantly affect the measurement results, making it difficult to meet the test accuracy requirements of micro- and nanoscale products such as advanced process chips and high-density packaging devices (such as BGA and flip chips). Especially when pin pitch is reduced to the micron level, errors caused by contact resistance and parasitic effects become more prominent, making it difficult to accurately measure device parameters such as resistance and voltage. In addition, the existing test pieces are prone to wear and ablation at the contact points with the pins under high-frequency use or high-temperature, high-load test environments, resulting in reduced contact performance and inaccurate test data. Test pieces made of ordinary metal materials are prone to surface loss due to repeated friction, resulting in increased contact resistance and unstable signal transmission. In high-temperature environments, the test piece material may deform or oxidize, further affecting test reliability, shortening the test piece's service life, and increasing test costs and maintenance burdens. In view of this, we propose a super-hard alloy head test piece with an ultra-small Kelvin gap. Summary of the Invention

[0004] The purpose of the present invention is to provide a super-hard alloy head test piece with an ultra-small Kelvin gap to solve the problem proposed in the above background technology that traditional two-wire measurement is difficult to accurately measure micro-nano scale product parameters in ultra-small pin testing of semiconductor devices due to the influence of wire and contact resistance; the existing test pieces are prone to wear and ablation under high frequency or high temperature, have poor contact performance and short life, and increase testing costs.

[0005] To achieve the above objectives, the present invention provides a super-hard alloy head test piece with an ultra-small Kelvin gap, comprising two metal test pieces, each of which is embedded with a super-hard alloy head, one side of which is coated with an insulating layer, and the metal test piece with the insulating layer and the metal test piece without the insulating layer are stacked in parallel to form a Kelvin combination; One end of the two metal test pieces is fixedly connected to a current pin and a voltage pin respectively. The current pin and the voltage pin are separated by an insulating layer to form a Kelvin gap to adapt to the precision testing requirements of ultra-small pins; the super-hard alloy head is used to reduce the ablation loss of the metal test piece during use and ensure the stability and reliability of its contact performance.

[0006] The beneficial effects of the present invention are: 1. In the present invention, the isolation design of the ultra-small Kelvin gap of 0.015mm and the insulating layer can effectively separate the current and voltage transmission paths, accurately eliminate the interference of wire resistance and contact resistance on the measurement results, and meet the high-precision requirements of ultra-small pins in precision testing. In addition, the super-hard alloy head is embedded in the special-shaped groove of the metal test piece. With its high hardness of more than 70HRC and high-temperature resistance of more than 1000℃, the ablation loss of the metal test piece during use is significantly reduced. Even in high-frequency testing or high-temperature environments, it can ensure stable contact between the first contact head and the second contact head and the object under test, maintain the reliability of the contact performance, and extend the service life of the test piece.

[0007] 2. In the present invention, the insulating layer is divided into a first coating layer adapted to the super-hard alloy head and a second coating layer adapted to the metal test piece. This layered design can effectively prevent short circuits between the current pin and the voltage pin, suppress parasitic capacitance and electromagnetic interference, and further improve the reliability of the test results, making it suitable for scenarios such as semiconductor and precision electronic component testing that have extremely high requirements on insulation and signal stability.

[0008] As a further improvement of the present technical solution, both metal test pieces are provided with special-shaped grooves for installing a super-hard alloy head. The super-hard alloy head is located inside the special-shaped groove. Both sides of the super-hard alloy head are provided with raised blocks, and the raised blocks are adapted to the recessed parts on the special-shaped groove, and the special-shaped groove is adapted to the super-hard alloy head.

[0009] The beneficial effect of adopting the above-mentioned further scheme is that the raised blocks on both sides of the super-hard alloy head fit tightly with the recessed parts of the special-shaped groove to form a joint similar to a mortise and tenon structure, which limits the lateral and longitudinal displacement and rotation of the alloy head on the metal test piece, ensuring that the alloy head will not loosen or fall off due to external forces (such as plugging and unplugging, vibration) during the test process, ensuring the stability of the overall structure of the test piece, and making the measurement process stable and reliable.

[0010] As a further improvement of the present technical solution, the top of the two metal test pieces near one end of the super-hard alloy head are respectively fixedly connected with a first contact head and a second contact head, the Kelvin gap is located between the first contact head and the second contact head, the tops of the first contact head and the second contact head are both arc-shaped, used to contact the object to be measured, and the first contact head and the second contact head are located on one side of the super-hard alloy head.

[0011] The beneficial effect of adopting the above further solution is that the arc-shaped design of the first contact head and the second contact head increases the contact area with the object to be measured, can better fit the objects to be measured with different surface morphologies, and improves the adaptability of the test piece to various types of objects to be measured.

[0012] As a further improvement of the present technical solution, the insulating layer is divided into a first coating and a second coating, both of which are located between two metal test pieces, the first coating is adapted to the super-hard alloy head, and the second coating is adapted to the metal test piece.

[0013] The beneficial effect of adopting the above-mentioned further scheme is that the first coating fits tightly to the super-hard alloy head, preventing the alloy head from causing short circuit between adjacent metal test pieces or pins due to its conductive properties, ensuring that the signal transmission paths of the current pin and the voltage pin do not interfere with each other; the second coating covers the surface of the metal test piece, further isolating the non-contact areas of the two test pieces, avoiding accidental conduction due to spacing fluctuations.

[0014] As a further improvement of the present technical solution, a gap is left between the current pin and the voltage pin, and the current pin and the voltage pin have the same shape. The Kelvin gap between the current pin and the voltage pin is 0.015 mm, which is used to adapt to small pins. The metal test piece is located above the current pin and the voltage pin and has two circular holes for installing the metal test piece.

[0015] The beneficial effect of adopting the above-mentioned further solution is that the ultra-small Kelvin gap of 0.015mm accurately adapts to small pins, separates the current and voltage paths, avoids interference from wire resistance and contact resistance, and ensures high precision when measuring parameters such as resistance and voltage of ultra-small pins; pins of the same shape ensure symmetrical distribution on both sides of the pin, so that the current injection point and the voltage detection point are strictly aligned, reducing the internal resistance voltage divider error of the measured pin.

[0016] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure assembly of the present invention; Figure 2 For the present invention Figure 1 Schematic diagram at point A in the middle; Figure 3 This is a schematic diagram of the overall disassembly of the present invention; Figure 4 is a schematic diagram of the insulating layer of the present invention; Figure 5 For the present invention Figure 4 Schematic diagram at point B in the middle.

[0018] The meaning of each number in the figure is: 100. Metal test piece; 200, super-hard alloy head; 201, first contact head; 202, second contact head; 300, insulating layer; 301, first coating layer; 302, second coating layer; 400, current pin; 500, voltage pin; 600. Kelvin gap. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] The present invention provides the following preferred embodiments See also Figure 1-Figure 5 As shown, this embodiment provides a super-hard alloy head test piece with an ultra-small Kelvin gap, comprising two metal test pieces 100, each of which is embedded with a super-hard alloy head 200. One side of one of the metal test pieces 100 is coated with an insulating layer 300, and the metal test piece 100 coated with the insulating layer 300 and the metal test piece 100 not coated with the insulating layer 300 are stacked in parallel to form a Kelvin combination; One end of the two metal test pieces 100 is fixedly connected to a current pin 400 and a voltage pin 500 respectively. The current pin 400 and the voltage pin 500 are separated by an insulating layer 300 to form a Kelvin gap 600 to adapt to the precision testing requirements of ultra-small pins; the super-hard alloy head 200 is used to reduce the ablation loss of the metal test piece 100 during use and ensure the stability and reliability of its contact performance.

[0021] The insulating layer 300 can be made of a highly wear-resistant epoxy polymer insulating adhesive, such as Loctite® ABLESTIK NCA 5836, a non-conductive adhesive with 30 wt% AlN filler, a thermal conductivity of 1.2 W / mK, and a surface roughness of Ra < 0.8 μm (ISO 4287) after curing. Combined with a precision coating process (slit coating or inkjet printing), a thickness tolerance of ±1 μm can be achieved, ensuring the geometric accuracy of the ultra-small Kelvin gap. The adhesive also resists flow during curing, preventing the risk of shorting caused by edge thickening. When the test probe or pin slides / presses repeatedly (such as high-frequency contact in automatic test equipment ATE), the filler can reduce the friction coefficient and prevent the metal test piece 100 from short-circuiting after the insulation layer is worn.

[0022] Therefore, based on the above features, the improvements of the present invention are described in detail: Traditional Kelvin test strips are arranged front to back. To prevent short circuits, a sufficient safety gap must be left between the current pin 400 and the voltage pin 500. When facing small-sized pins, the pin tip is very likely to extend beyond the pin area, resulting in poor contact. In addition, for Kelvin test strips arranged front to back, the current pin 400 and the voltage pin 500 are not completely consistent in mechanical structure, resulting in uneven contact force, which affects long-term reliability. Therefore, an insulating layer 300 is applied on one side between the current pin 400 and the voltage pin 500 to form an ultra-small Kelvin gap 600. On the one hand, the Kelvin gap 600 occupies a small space and can be used for contact of ultra-small pins. It can achieve electrical isolation between the current path and the voltage detection path in an extremely small physical space, avoiding interference with the measurement results caused by wire resistance and contact resistance, thereby ensuring high-precision measurement of parameters such as resistance and voltage of ultra-small pins. It is particularly suitable for precise testing in space-constrained scenarios such as semiconductor micro-nano devices and high-density integrated chips. On the other hand, because the current pin 400 and the voltage pin 500 are arranged in parallel, their structures are almost identical and have the same mechanical and electrical properties, making the contact more stable and reliable; Since traditional Kelvin test pieces are usually made of a single conductive material, although they have certain wear resistance, their contact surfaces are easily worn during frequent tests, resulting in a decrease in contact quality. Especially in high current tests, since the contact part between the test piece and the chip will generate high temperature, conventional conductive materials such as beryllium copper have low heat resistance and are prone to burning and contact degradation. Therefore, the super-hard alloy head 200 designed to be embedded in the metal test piece 100, with its extremely high hardness of more than 70HRC, can withstand repeated mechanical friction in the test, significantly reduce wear, extend the service life of the test piece and improve the reliability of long-term testing; at the same time, it can still maintain good mechanical properties in high temperature environments above 1000°C, which can effectively reduce test piece burning, stabilize contact performance, and ensure the accuracy and stability of tests in high temperature environments. It is especially suitable for high-frequency testing, high-temperature working conditions or scenarios with high wear resistance requirements.

[0023] On the basis of the above, the specific structure is disclosed in detail: To achieve the connection between the super-hard alloy head 200 and the metal test piece 100, the two metal test pieces 100 are disclosed in detail, such as Figure 1As shown, both metal test pieces 100 are provided with special-shaped grooves for installing super-hard alloy heads 200. The super-hard alloy heads 200 are located inside the special-shaped grooves. Both sides of the super-hard alloy heads 200 are provided with protrusions, and the protrusions are matched with the depressions on the special-shaped grooves. The special-shaped grooves are matched with the super-hard alloy heads 200. Therefore, by matching the special-shaped grooves on the metal test pieces 100 with the super-hard alloy heads 200, the super-hard alloy heads 200 are firmly embedded in the metal test pieces 100, ensuring that the two maintain reliable mechanical connection and electrical conduction during the test process, avoiding problems such as poor contact and signal interruption due to loosening, displacement or falling off, thereby improving the stability and consistency of the test structure, and ensuring the measurement accuracy and reliability in high-frequency tests or complex working conditions such as vibration and high-temperature environments.

[0024] Furthermore, to achieve the measurement of the metal test piece 100, the structure of the metal test piece 100 is further disclosed in detail, such as Figure 1 and Figure 2 As shown, the top of the two metal test pieces 100 near one end of the super-hard alloy head 200 are respectively fixedly connected with the first contact head 201 and the second contact head 202, and the Kelvin gap 600 is located between the first contact head 201 and the second contact head 202. The tops of the first contact head 201 and the second contact head 202 are both arc-shaped, which are used to contact the object to be measured, and the first contact head 201 and the second contact head 202 are located on one side of the super-hard alloy head 200. Therefore, the arc shape of the top of the contact head can increase the contact area with the object to be measured, and at the same time adapt to the slight undulations on the surface of the object to be measured through elastic deformation, thereby reducing poor contact caused by surface roughness or position deviation.

[0025] However, to achieve the installation of the insulating layer 300, specifically as Figure 3-Figure 5 As shown, the insulating layer 300 is divided into a first coating 301 and a second coating 302. The first coating 301 and the second coating 302 are both located between the two metal test pieces 100. The first coating 301 is adapted to the super-hard alloy head 200, and the second coating 302 is adapted to the metal test piece 100. The super-hard alloy head 200 serves as a key node for current or voltage transmission. The first coating 301 on its surface can electrically isolate adjacent metal test pieces 100 or other conductors to avoid direct conduction of the current path and the voltage detection path near the alloy head; the main body of the metal test piece 100 is usually a conductive material, and the second coating 302 can isolate the non-contact area between the two test pieces to avoid accidental conduction due to fluctuations in the spacing when the test pieces are stacked in parallel.

[0026] Next, the metal test piece 100 needs to be connected to the external device, as shown in the following example: Figure 3As shown, there is a gap between the current pin 400 and the voltage pin 500, and the current pin 400 and the voltage pin 500 have the same shape. The Kelvin gap 600 between the current pin 400 and the voltage pin 500 is 0.015 mm, which is used to adapt to small pins. The metal test piece 100 is located above the current pin 400 and the voltage pin 500 and has two circular holes for mounting the metal test piece 100. The 0.015 mm gap can accurately match ultra-small pins such as fan-out pins and FlipChip solder balls in advanced semiconductor packages. Their size is close to the characteristic line width in the integrated circuit process, meeting the testing requirements of nano-scale devices; the current pin and the voltage pin 500 have the same shape, ensuring that the two are symmetrically distributed on both sides of the pin, so that the current injection point and the voltage detection point are strictly aligned, reducing the voltage divider error of the internal resistance of the tested pin. When measuring the resistance of nanowires, the symmetrical pin layout can avoid measurement deviation caused by position offset.

[0027] Working steps of the present invention: This test piece is based on the Kelvin four-wire method principle. A Kelvin combination is formed by stacking two metal test pieces 100 in parallel. The current pin 400 and the voltage pin 500 are isolated by an insulating layer 300 to construct an ultra-small Kelvin gap 600 of 0.015mm, realizing electrical separation of the current path and the voltage detection path. During the test, the current pin 400 is connected to the power supply to provide a constant current to the object under test; the voltage pin 500 is connected to a high-impedance measuring instrument to detect the actual voltage at both ends of the object under test. The super-hard alloy head 200 is embedded in the special-shaped groove of the metal test piece 100. With its high hardness and high temperature resistance, it supports the stable contact between the arc-shaped first and second contact heads and the object under test, ensuring stable current injection and accurate transmission of voltage signals. The double-layer coating of the insulating layer 300 is respectively adapted to the gold head and the metal sheet to prevent short circuit between the pins; the metal sheet is fixed above the pin through a circular hole to maintain the stability of the gap size and ensure measurement accuracy.

[0028] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A superhard alloy head test piece with an ultra-small Kelvin gap, comprising two metal test pieces (100), characterized in that: Both metal test pieces (100) are embedded with superhard alloy heads (200), and both metal test pieces (100) are provided with special-shaped grooves. Both sides of the superhard alloy heads (200) are provided with protrusions that are fixed in conjunction with the recesses of the special-shaped grooves. One side of one of the metal test pieces (100) is coated with an insulating layer (300), and the metal test piece (100) coated with the insulating layer (300) and the metal test piece (100) not coated with the insulating layer (300) are stacked in parallel to form a Kelvin combination; One end of the two metal test pieces (100) is fixedly connected to a current pin (400) and a voltage pin (500), respectively. The current pin (400) and the voltage pin (500) are isolated from each other by an insulating layer (300), forming a Kelvin gap (600) of 0.015 mm.

2. The ultra-small Kelvin gap super-hard alloy head test piece according to claim 1, characterized in that: The tops of the two metal test pieces (100) close to one end of the superhard alloy head (200) are respectively fixedly connected with a first contact head (201) and a second contact head (202), and the Kelvin gap (600) is located between the first contact head (201) and the second contact head (202).

3. The ultra-small Kelvin gap super-hard alloy head test piece according to claim 2, characterized in that: The tops of the first contact head (201) and the second contact head (202) are both arc-shaped and are used to contact the object to be measured, and the first contact head (201) and the second contact head (202) are located on one side of the superhard alloy head (200).

4. The ultra-small Kelvin gap super-hard alloy head test piece according to claim 1, characterized in that: The insulating layer (300) is divided into a first coating layer (301) and a second coating layer (302), and the first coating layer (301) and the second coating layer (302) are both located between two metal test pieces (100).

5. The ultra-small Kelvin gap super-hard alloy head test piece according to claim 4, characterized in that: The first coating (301) is compatible with the superhard alloy head (200), and the second coating (302) is compatible with the metal test piece (100).

6. The ultra-small Kelvin gap super-hard alloy head test piece according to claim 1, characterized in that: A gap is left between the current pin (400) and the voltage pin (500), and the current pin (400) and the voltage pin (500) have the same shape.

7. The ultra-small Kelvin gap super-hard alloy head test piece according to claim 1, characterized in that: The Kelvin gap between the current pin (400) and the voltage pin (500) is 0.015 mm, which is used to adapt to small pins.

8. The ultra-small Kelvin gap super-hard alloy head test piece according to claim 1, characterized in that: The metal test piece (100) is located above the current pin (400) and the voltage pin (500) and has two circular holes for mounting the metal test piece (100).

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