Wafer testing device

Abstract

The utility model relates to the field of wafer testing, and provides a wafer testing device which is used for testing the magnetoelectric performance of a to-be-tested crystal grain on a to-be-tested wafer and comprises a base frame, a permanent magnet and a probe card fixedly installed on the base frame, the thickness direction of the probe card is parallel to the vertical direction, and the probe card is provided with a probe extending below the probe card; when testing operation is carried out, a wafer to be tested is arranged below the probe card in the posture that the thickness direction is parallel to the vertical direction, a crystal grain to be tested is located in the magnetic field environment of the permanent magnet, and the probe is electrically connected with the crystal grain to be tested. The probe card is provided with a first hole, the position of the first hole is opposite to the position of the probe in the vertical direction, and at least part of the permanent magnet extends into the first hole from top to bottom. The first hole is formed in the needle card, so that the permanent magnet is closer to the wafer, the permanent magnet can generate a magnetic field at the to-be-tested crystal grain, the external interference is smaller, the precision of the magnetic field at the to-be-tested crystal grain is improved, and the test accuracy and reliability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wafer testing, in particular to a wafer testing device. BACKGROUND

[0002] There are two key testing stages in the process of chip production: one is the test performed at the wafer stage, i.e. CP test (Chip Probe Test); the other is the test performed after the chip is packaged, i.e. FT test (Final Test). Among them, CP test is performed before the wafer is cut and packaged after the wafer manufacturing is completed, which mainly verifies the electrical characteristics and functionality of each die on the wafer, such as threshold voltage, on-resistance, leakage current, timing and function tests, to ensure that each die can basically meet the characteristics or design specification of the device. CP test can detect the manufacturing process level and help identify and eliminate unqualified dies to reduce the cost of subsequent packaging and testing. FT test is performed after the chip is packaged to ensure the performance and reliability of the packaged chip in different environmental conditions, such as environmental testing, aging testing and application-specific performance testing.

[0003] Among them, referring to the patent document with the patent publication number TW202013546A, the testing device at the wafer stage includes a needle card, and one or more probes on the needle card form an electrical connection by contacting the pads or bumps of the dies on the wafer, so that the test signal can be transmitted to the pads or bumps of each die on the wafer, and the feedback signal is collected for analysis, thereby realizing the function and performance test of each die on the wafer.

[0004] In the wafer stage test scenario of magnetic sensor chips, magnetic field is an important test condition, so it is usually necessary to set up a magnetic field near the wafer to be tested. Referring to the patent document with the patent publication number TW202013546A, a permanent magnet is fixed above the needle card, and the permanent magnet generates a magnetic field perpendicular to the wafer to be tested, thereby realizing the magnetic sensing performance test of the circuit on the wafer to be tested in the Z-axis magnetic field parameter. SUMMARY

[0005] The present application aims to provide a wafer testing device, which is beneficial to improve the magnetic field precision at the die to be tested, and is beneficial to improve the testing accuracy and reliability.

[0006] The application provides a wafer testing device for testing the magnetoelectric performance of a to-be-tested die on a to-be-tested wafer, comprising a base frame, a permanent magnet and a needle card fixedly installed on the base frame, the thickness direction of the needle card is parallel to the vertical direction, and the needle card has a probe extending downward; during the testing operation, the to-be-tested wafer is placed below the needle card in a posture with the thickness direction parallel to the vertical direction, the to-be-tested die is located in the magnetic field environment of the permanent magnet, and the probe is electrically connected with the to-be-tested die; a first hole is formed in the needle card, the position of the first hole is opposite to the position of the probe along the vertical direction, and the permanent magnet at least partially extends into the first hole from top to bottom.

[0007] As can be seen from the above, in the prior art, since the needle card is located between the permanent magnet and the to-be-tested die, if there is a magnetic field interference factor on the needle card, the magnetic field generated by the permanent magnet at the to-be-tested die may be interfered, and the needle card generates an interference magnetic field after being powered on, which may cause the magnetic field precision at the to-be-tested die to decrease; in the application, since the first hole is arranged at the position opposite to the probe on the needle card, and the first hole does not generate an interference magnetic field, it is beneficial to weaken the interference magnetic field generated by the needle card at the probe and the to-be-tested die after being powered on, and since the permanent magnet is at least partially located in the first hole, it is beneficial to shorten the distance between the permanent magnet and the to-be-tested die on the to-be-tested wafer, and shorten the closed-loop magnetic field path between the permanent magnet and the to-be-tested die, which is beneficial to reduce the magnetic field interference factors between the permanent magnet and the to-be-tested die, and weaken the interference of the needle card on the magnetic field generated by the permanent magnet at the to-be-tested die.

[0008] For example, in the prior art, since the permanent magnet is located above the needle card, the closed-loop magnetic field path between the permanent magnet and the to-be-tested die is relatively long, which may cause more other dies on the to-be-tested wafer to also be located on the closed-loop magnetic field path, these dies have an interference effect on the direction of the magnetic field, which may cause the strength and direction of the magnetic field generated by the permanent magnet at the to-be-tested die to change, thereby causing the magnetic field precision at the to-be-tested die to decrease; in the application, the permanent magnet is at least partially located in the first hole, which is beneficial to shorten the distance between the permanent magnet and the to-be-tested die on the to-be-tested wafer, and shorten the closed-loop magnetic field path between the permanent magnet and the to-be-tested die, thereby being beneficial to reduce the number of dies on the closed-loop magnetic field path of the to-be-tested die, and reduce the magnetic field interference of other dies on the to-be-tested die.

[0009] In summary, the application is beneficial to make the magnetic field generated by the permanent magnet at the to-be-tested die less interfered, is beneficial to improve the magnetic field precision at the to-be-tested die, and is beneficial to improve the testing accuracy and reliability.

[0010] In addition, since the application is beneficial to shorten the distance between the permanent magnet and the to-be-tested die on the to-be-tested wafer, in order to generate the same magnetic field at the to-be-tested die, the application can use a permanent magnet with a smaller size / weaker magnetic field, which is beneficial to reduce the cost of the permanent magnet.

[0011] In one feasible approach, the first hole is through the pin.

[0012] As can be seen from the above, this allows the permanent magnet to be extended closer to the grain being tested, which further helps to improve the magnetic field accuracy at the grain being tested.

[0013] In one possible implementation, the lower end opening size of the first hole is less than or equal to the upper end opening size of the first hole, and the probe passes through the hole wall of the lower end opening and extends below the lower end opening.

[0014] As can be seen from the above, a larger upper aperture is conducive to the passage (or accommodation) of permanent magnets, while a smaller lower aperture is conducive to shortening the distance between the probe's exit point and the grain to be tested, thus shortening the probe's overhang size and improving the probe's stability and reliability.

[0015] In one possible implementation, the pin clip includes a circuit board and an insulating layer fixed to the lower sidewall of the circuit board, with the probe extending through the insulating layer and extending below the pin clip; a first hole penetrates the circuit board, or a first hole penetrates both the circuit board and the insulating layer.

[0016] As can be seen from the above, since the first hole passes through the circuit board (no current flows through the circuit board at the position where the probe and the die to be tested are directly opposite each other), it is further beneficial to reduce the interference magnetic field generated at the probe and the die to be tested after the probe is powered on, and further beneficial to improve the magnetic field accuracy at the die to be tested.

[0017] In one possible implementation, the first hole has an upper hole section located on a circuit board and a lower hole section located on an insulating layer, with the permanent magnet extending at least partially into the lower hole section.

[0018] As can be seen from the above, this is beneficial to further shorten the distance between the permanent magnet and the grain to be tested, and further improve the magnetic field accuracy at the grain to be tested.

[0019] In one feasible approach, the vertical distance between the permanent magnet and the wafer under test is greater than 1.4 mm and less than 4.4 mm, or equal to 1.4 mm, or equal to 4.4 mm.

[0020] In one feasible implementation, the thickness of the circuit board is greater than or equal to 5 millimeters.

[0021] As can be seen from the above, this helps to improve the structural strength of the circuit board, reduce deformation, improve the dimensional accuracy of the circuit board, and improve the positional accuracy of the probe.

[0022] In one possible implementation, the pin clip is detachably mounted to the base frame by a fastening pin; the circuit board of the pin clip has a countersunk hole that runs vertically through it, and the fastening pin passes through the countersunk hole from bottom to top and is connected to the base frame, with the head of the fastening pin at least partially submerged in the countersunk hole.

[0023] In an implementation, the permanent magnet is mounted on the base frame through an adjusting assembly for adjusting the position of the permanent magnet; the adjusting assembly comprises a first adjuster, a second adjuster and a third adjuster, the first adjuster is used for adjusting the position of the permanent magnet in a vertical direction, the second adjuster is used for adjusting the position of the permanent magnet in a second direction, and the third adjuster is used for adjusting the position of the permanent magnet in a third direction; the vertical direction, the second direction and the third direction are perpendicular to each other in pairs.

[0024] In an implementation, the permanent magnet is rotatably arranged relative to the base frame, and an angle between an axis of rotation of the permanent magnet and a direction of pole distribution of the permanent magnet is provided, so as to adjust the direction of the magnetic field at the to-be-tested wafer by rotating the permanent magnet.

[0025] In an implementation, the axis of rotation of the permanent magnet is in a vertical direction.

[0026] In an implementation, the direction of pole distribution of the permanent magnet is perpendicular to the axis of rotation.

[0027] In an implementation, the permanent magnet is mounted on the base frame through a rotating component, and the permanent magnet is fixed to a lower end of the rotating component.

[0028] In an implementation, the rotating component is a rotating shaft of an electric motor.

[0029] In an implementation, the permanent magnet is in a circular ring shape or a circular disc shape, a center line of the permanent magnet coincides with the axis of rotation, and a magnetization direction of the permanent magnet is in a radial direction.

[0030] In an implementation, a maximum distance from the axis of rotation to an outer contour of the permanent magnet is L, and 3.5 mm≤L≤4.5 mm.

[0031] In an implementation, the permanent magnet is a multi-pole magnetic ring, and a ring body of the multi-pole magnetic ring is directly opposite to the probe in the vertical direction. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a partial cross-sectional view of a wafer testing device in the related art, and a schematic diagram of magnetic field lines corresponding to a permanent magnet;

[0033] Figure 2 is a perspective cross-sectional view of a wafer testing device provided by the present embodiment and a partial enlarged view of the wafer testing device; Figure 2

[0034] Figure 3 is a partial cross-sectional view of a wafer testing device provided by the present embodiment, and a schematic diagram of magnetic field lines corresponding to a permanent magnet;

[0035] Figure 4is a partial sectional view of a wafer testing device provided by another embodiment of the present application;

[0036] Figure 5 is a partial sectional view of a wafer testing device provided by another embodiment of the present application;

[0037] Figure 6 is a partial sectional view of a wafer testing device provided by another embodiment of the present application; DETAILED DESCRIPTION

[0038] First refer to Figure 1 , Figure 1 is a partial sectional view of a wafer testing device and a schematic diagram of the magnetic field distribution of the corresponding permanent magnet in the related art, wherein the direction of the Z' axis is the vertical direction. It is achieved by fixing a permanent magnet 2' above the needle card 3', the wafer to be tested 1' is placed below the needle card 3' in the posture of parallel to the direction of the Z' axis in the thickness direction, the die to be tested 11' is located in the magnetic field environment of the permanent magnet 2', the probe 31' is electrically connected with the die to be tested 11', and the magnetic and electric performance of the die to be tested 11' is tested.

[0039] Among them, refer to Figure 1 the schematic diagram of the magnetic field distribution of the permanent magnet 2' in Figure 1 , it can be seen that in the related art, the distance between the permanent magnet 2' located above the needle card 3' and the die to be tested 11' is far, so the closed loop magnetic field path between the permanent magnet 2' and the die to be tested 11' is long, which may cause other dies on the wafer to be tested to also be located on the closed loop magnetic field path. These dies have interference effect on the direction of the magnetic field, which will cause the magnetic field strength and direction generated by the permanent magnet 2' at the die to be tested 11' to change, thereby causing the magnetic field precision at the die to be tested 11' to decrease.

[0040] Moreover, in the related art, the needle card 3' is located between the permanent magnet 2' and the die to be tested 11', if there is a magnetic field interference factor on the needle card 3', it may also interfere with the magnetic field generated by the permanent magnet 2' at the die to be tested 11', and the needle card 3' will generate an interference magnetic field after being energized, which will also cause the magnetic field precision at the die to be tested 11' to decrease.

[0041] In order to improve the magnetic field precision of the permanent magnet generated at the die to be tested, the present embodiment provides a wafer testing device. The present embodiment will be described below in conjunction with the drawings. Those skilled in the art can know that with the development of technology and the appearance of new scenarios, the technical solutions provided by the present embodiment are also applicable to similar technical problems.

[0042] Refer to Figure 2 , Figure 3 , Figure 2 , Figure 3A unified spatial rectangular coordinate system (right-hand system) is adopted to represent the relative position relationship between the features. In this embodiment, the Z-axis direction is the vertical direction, the X-axis direction is the second direction, and the Y-axis direction is the third direction.

[0043] The wafer testing device of this embodiment is used to test the magnetoelectric performance of the to-be-tested die 11 on the to-be-tested wafer 1. The wafer testing device includes a base frame (not shown in the figure), a permanent magnet 2, and a needle card 3 fixedly installed on the base frame. The thickness direction of the needle card 3 is parallel to the Z-axis direction, and the needle card 3 has a plurality of probes 31 extending downward therefrom. When performing the testing operation, the to-be-tested wafer 1 is placed below the needle card 3 in a posture with the thickness direction parallel to the Z-axis direction, the to-be-tested die 11 is located in the magnetic field environment of the permanent magnet 2, and the to-be-tested die 11 is tested by electrically connecting the probes 31 and the to-be-tested die 11.

[0044] It should be noted that the to-be-tested wafer 1 includes a plurality of dies. For the convenience of illustration, only one die (i.e., the to-be-tested die 11) is shown on the to-be-tested wafer 1 in this embodiment. During the testing operation, the relative position of the to-be-tested wafer 1 and the needle card 3 can be adjusted to test each die on the to-be-tested wafer 1 one by one. The wafer testing device of this embodiment is configured to test the magnetoelectric performance of only one die (i.e., the to-be-tested die 11) at the same time. Alternatively, in other embodiments of the present application, the wafer testing device can also be configured to test a plurality of to-be-tested dies at the same time.

[0045] Further, the wafer testing device of the embodiment further comprises an adjusting assembly (not shown in the figure) and a motor (not shown in the figure), the permanent magnet 2 is installed on the base frame through the adjusting assembly and the motor, and the adjusting assembly and the motor are both located above the needle card 3 (on the positive side of the Z axis), specifically, the adjusting assembly comprises a Z-axis adjuster (an example of a first adjuster), an X-axis adjuster (an example of a second adjuster) and a Y-axis adjuster (an example of a third adjuster), and the base frame, the Y-axis adjuster, the X-axis adjuster, the Z-axis adjuster, the motor and the permanent magnet 2 are sequentially connected, wherein the Y-axis adjuster is movably connected to the base frame along the Y-axis direction, the X-axis adjuster is movably connected to the Y-axis adjuster along the X-axis direction, the Z-axis adjuster is movably connected to the X-axis adjuster along the Z-axis direction, the housing of the motor is fixedly connected to the Z-axis adjuster, the rotation axis of the rotating shaft 4 (an example of a rotating part) of the motor is parallel to the Z-axis direction, the permanent magnet 2 is fixedly connected to the lower end (the negative end of the Z axis) of the rotating shaft 4 of the motor, the permanent magnet 2 is in the shape of a disc, the center line of the permanent magnet 2 coincides with the rotation axis of the rotating shaft 4 of the motor, and the distribution direction of the south pole and the north pole of the permanent magnet 2 is perpendicular to the Z-axis direction (the magnetization direction of the permanent magnet 2 is along the radial direction). In this way, the position of the permanent magnet 2 in the X-axis direction, the Y-axis direction and the Z-axis direction can be adjusted through the adjusting assembly, so as to facilitate flexible cooperation with different needle cards 3, adapt to the testing requirements of different wafers to be tested, and facilitate the rotation of the permanent magnet 2 through the motor, so as to adjust the direction of the magnetic field generated by the permanent magnet 2 at the wafer to be tested, thereby facilitating the testing of the magnetoelectric performance of the wafer to be tested 11 in different directions (for example, the X-axis direction and the Y-axis direction).

[0046] In the embodiment, the needle card 3 comprises a circuit board 33 and an insulating layer 34 fixed on the lower side wall of the circuit board 33, and a first hole 32 penetrating through the circuit board 33 and the insulating layer 34 in the Z-axis direction is formed, the permanent magnet 2 extends into the first hole 32 from top to bottom (in the negative direction of the Z axis), the first hole 32 has an upper hole section located at the circuit board 33 and a lower hole section located at the insulating layer 34, and the probe 31 extends out from the hole wall of the lower hole section and below the needle card 3 (the probe 31 extends out from the hole wall of the first hole 32, and naturally faces the first hole 32 in the Z-axis direction).

[0047] Compared with Figure 1The permanent magnet 2' is located above the needle card 3' in the technical solution shown. In the embodiment, the needle card 3 is provided with the first hole 32 at the position opposite to the probe 31, and the first hole 32 does not generate an interference magnetic field, thereby facilitating weakening of the interference magnetic field generated at the probe 31 and the to-be-tested die 11 of the needle card 3 after being energized. Moreover, in the embodiment, the permanent magnet 2 is at least partially located in the first hole 32, thereby facilitating shortening of the distance between the permanent magnet 2 and the to-be-tested die 11 on the to-be-tested wafer 1, and shortening of the closed-loop magnetic field path (magnetic force line path) between the permanent magnet 2 and the to-be-tested die 11, thereby facilitating reduction of other magnetic field interference factors between the permanent magnet 2 and the to-be-tested die 11, and weakening of the interference of the needle card 3 on the magnetic field generated at the to-be-tested die 11 by the permanent magnet 2. For example, the embodiment facilitates reduction of the number of dies on the closed-loop magnetic field path of the to-be-tested die 11 (the magnetic force line distribution of the permanent magnet 2 is shown by the dotted line in FIG. 11), thereby reducing the magnetic field interference of other dies on the to-be-tested die 11. Figure 3

[0048] In contrast to the present application, Figure 1 In the technical solution shown, the permanent magnet 2' is located above the needle card 3', and the closed-loop magnetic field path between the permanent magnet 2' and the to-be-tested die 11' is relatively long, which may result in a situation that more other dies on the to-be-tested wafer 1' are also located on the closed-loop magnetic field path, thereby causing interference of the other dies on the magnetic field at the to-be-tested die 11'.

[0049] In the embodiment, the permanent magnet 2 is entirely located in the lower hole section of the first hole 32. Alternatively, in other embodiments of the present application, the permanent magnet can also be partially extended into the lower hole section of the first hole (partially located in the upper hole section), or not extended into the lower hole section but only extended into the upper hole section. Of course, it is preferred that the permanent magnet is at least partially extended into the lower hole section (even entirely extended into the lower hole section), so as to make the permanent magnet more close to the to-be-tested die, thereby facilitating further improvement of the magnetic field precision at the to-be-tested die.

[0050] ​In the embodiment, the first hole 32 has a constant cross-sectional profile shape and size from top to bottom (the upper end aperture size of the first hole 32 is equal to the lower end aperture size), and preferably, in other embodiments of the present application, the lower end aperture size of the first hole is smaller than the upper end aperture size of the first hole, and the probe penetrates out of the hole wall of the lower end aperture and extends downward below the lower end aperture. In this way, the larger upper end aperture is conducive to the passage (or accommodation) of the permanent magnet, and the smaller lower end aperture is conducive to reducing the size between the penetration position of the probe and the to-be-tested die, thereby facilitating the reduction of the overhanging size of the probe and the improvement of the stability and reliability of the probe. Specifically, the first hole of the embodiment can be a stepped hole, for example, which has a step at the upper hole section or the lower hole section, and the cross-sectional size of the first hole at the upper side of the step (Z-axis positive side) is larger than the cross-sectional size of the first hole at the lower side of the step (Z-axis negative side), and the permanent magnet can only extend to the part of the hole section at the upper side of the step, and of course, it is preferred that the step of the first hole is located at the lower hole section, so that the permanent magnet can extend to a position closer to the to-be-tested die, thereby facilitating the improvement of the magnetic field accuracy at the to-be-tested die.

[0051] Alternatively, in other embodiments of the present application, the first hole can also be a blind hole opening on the upper surface of the needle card without penetrating through the needle card (for example, the first hole only penetrates through the circuit board of the needle card but does not penetrate through the insulating layer); wherein, in the case that the first hole is provided as a blind hole opening on the upper surface of the needle card, it is preferred that the first hole only penetrates through the circuit board of the needle card but does not penetrate through the insulating layer, so that the circuit board will not have current flowing through the position directly opposite to the probe and the to-be-tested die, which is conducive to weakening the interference magnetic field generated at the probe and the to-be-tested die after the needle card is powered on, and further conducive to improving the magnetic field accuracy at the to-be-tested die; in this embodiment, the position of the first hole and the position of the probe are vertically opposite.

[0052] In the embodiment, the cross-sectional profile shape of the first hole 32 is a square, the cross-sectional profile side length of the first hole 32 is 9 millimeters, and the radius of the permanent magnet 2 is 4 millimeters (i.e., the maximum distance from the rotation axis of the permanent magnet 2 to the outer profile is 4 millimeters), wherein, the permanent magnet 2 has a gap with the side wall of the first hole 32, thereby ensuring that the permanent magnet 2 does not contact and collide with the side wall of the first hole 32.

[0053] Further, in order to leave sufficient space allowance between the permanent magnet 2 and the side wall of the first hole 32, the gap between the edge of the permanent magnet 2 and the side wall of the first hole 32 is preferably greater than or equal to 0.5 millimeters.

[0054] In this embodiment, the distance between the permanent magnet 2 and the wafer to be tested 1 in the Z-axis direction is 4.4 mm. Alternatively, in other embodiments of the present application, the distance between the permanent magnet and the wafer to be tested in the Z-axis direction can also be set to other sizes. As long as the permanent magnet is at least partially located in the first hole, the distance between the permanent magnet and the wafer to be tested can be shortened, thereby facilitating the improvement of the magnetic field accuracy at the wafer to be tested. Of course, it is preferred that the distance between the permanent magnet and the wafer to be tested in the Z-axis direction be greater than 1.4 mm and less than 4.4 mm, or equal to 1.4 mm, or equal to 4.4 mm. By setting the distance between the permanent magnet and the wafer to be tested in the Z-axis direction to be greater than or equal to 1.4 mm, interference between the permanent magnet and the probe can be avoided. By setting the distance between the permanent magnet and the wafer to be tested in the Z-axis direction to be less than or equal to 4.4 mm, the distance between the permanent magnet and the wafer to be tested is close enough, thereby making the magnetic field generated by the permanent magnet at the wafer to be tested less disturbed, further improving the magnetic field accuracy of the permanent magnet at the wafer to be tested. Moreover, under the condition of ensuring the same magnetic field strength generated at the wafer to be tested, setting a smaller distance between the permanent magnet and the wafer to be tested can correspondingly select a smaller size / magnetic field weaker permanent magnet, thereby facilitating the reduction of the cost of the permanent magnet.

[0055] In this embodiment, the permanent magnet 2 is in the shape of a disc. Alternatively, in other embodiments of the present application, the permanent magnet can also be in other shapes.

[0056] For example, Figure 4 A partial cross-sectional view of another embodiment of the present application is shown. The basic scheme of this embodiment is the same as that of the present embodiment, except that the permanent magnet 2a of this embodiment is in the shape of a ring, the center line of the permanent magnet 2a coincides with the rotation axis of the rotating shaft 4a of the motor and is in the Za-axis direction (vertical direction), and the magnetization direction of the permanent magnet 2a is in the radial direction thereof. In this way, by rotating the permanent magnet 2a, the magnetic field direction at the wafer to be tested can also be adjusted, thereby facilitating the testing of the magnetoelectric performance of the wafer to be tested in different magnetic field directions.

[0057] For another example, Figure 5 A partial cross-sectional view of another embodiment of the present application is shown. The basic scheme of this embodiment is the same as that of the present embodiment, except that the permanent magnet of this embodiment is a multi-pole magnetic ring 2b, the center line of the multi-pole magnetic ring 2b coincides with the rotation axis of the rotating shaft 4b of the motor and is in the Zb-axis direction (vertical direction), the ring body of the multi-pole magnetic ring 2b is directly opposite the probe 31b in the Zb-axis direction, the wafer to be tested 11b is located on the negative side of the Zb-axis of the ring body of the multi-pole magnetic ring 2b and is directly opposite the ring body of the multi-pole magnetic ring 2b in the Zb-axis direction. In this way, by rotating the multi-pole magnetic ring 2b, the magnetic pole polarity opposite the wafer to be tested 11b can be adjusted, thereby adjusting the magnetic field direction at the wafer to be tested 11b, thereby facilitating the testing of the magnetoelectric performance of the wafer to be tested 11b in different magnetic field directions.

[0058] In the embodiment, the rotation axis of the permanent magnet 2 is perpendicular to the direction of the magnetic pole distribution of the permanent magnet 2; alternatively, in other embodiments of the present application, the rotation axis of the permanent magnet and the direction of the magnetic pole distribution of the permanent magnet have an included angle, which can be other angles. On the basis of the rotation of the permanent magnet, the direction of the magnetic pole distribution of the permanent magnet and the rotation axis of the permanent magnet are arranged to have a certain included angle, the direction of the magnetic field at the to-be-tested crystal grain is adjusted by rotating the permanent magnet, and thus the permanent magnet can provide a magnetic field of a specified direction at the to-be-tested crystal grain to perform the magneto-electric performance test.

[0059] For example, Figure 6 A perspective sectional view and a partial enlarged view of a wafer testing device according to another embodiment of the present application are shown, the basic scheme of the embodiment is the same as that of the present embodiment, and the difference lies in that the center line M2 of the permanent magnet 2c and the rotation axis M1 of the rotating shaft 4c of the motor have an included angle of 20°, and the direction of the magnetic pole distribution of the permanent magnet 2c is perpendicular to the center line M2 thereof, so that the direction of the magnetic field at the to-be-tested crystal grain 11c can also be adjusted by rotating the permanent magnet 2c, and thus the permanent magnet 2c can provide a magnetic field of a specified direction at the to-be-tested crystal grain 11c to perform the magneto-electric performance test; preferably, the maximum distance from the rotation axis M1 of the permanent magnet 2c to the outer contour of the permanent magnet 2c is L, and 3.5 mm≤L≤4.5 mm, on the basis of the magnetic field provided by the permanent magnet meeting the testing requirements, designing a smaller size of the permanent magnet is beneficial to reducing the size of the first hole, and thus is beneficial to reducing the influence on the circuit design, and the size of the permanent magnet is smaller, and the weight is also lighter, which is beneficial to the improvement of the installation precision and adjustment precision. Alternatively, the included angle between the center line M2 of the permanent magnet 2c and the rotation axis M1 of the permanent magnet 2c can also be, for example, 45°, 60°, etc.

[0060] In the embodiment, the needle card 3 is detachably mounted on the base frame by the fastening nail 5, specifically, a countersunk hole 35 penetrating along the Z-axis direction is formed on the circuit board 33 of the needle card 3, the fastening nail 5 passes through the countersunk hole 35 from bottom to top and is fixedly connected with the base frame, in order to reduce the influence of the fastening nail 5 on the testing operation (for example, if the head of the fastening nail 5 has an excessively large protruding size, it will affect the movement range of the to-be-tested wafer during the installation / movement process), the head of the fastening nail 5 is at least partially sunk in the countersunk hole 35.

[0061] Further, in the embodiment, the thickness of the circuit board 33 of the needle card 3 is preferably designed to be greater than or equal to 5 mm, which is beneficial to improving the strength of the circuit board 33, reducing the deformation of the circuit board 33, improving the installation and size precision of the needle card 3, improving the position precision of the probe 31, and thus is beneficial to improving the stability and reliability of the wafer test.

[0062] In the embodiment, the insulating layer 34 can be one or more of epoxy resin, silica gel and the like.

[0063] In the embodiment, the Y-axis adjuster is movably connected to the base frame along the Y-axis direction. For example, the Y-axis adjuster and the base frame can be guided to move through the cooperation of a sliding block and a sliding groove, or through the cooperation of a sliding block and a guide rod, which is not limited herein. Similarly, the connection mode of the X-axis adjuster and the Y-axis adjuster, and the connection mode of the Z-axis adjuster and the X-axis adjuster can refer to the connection mode of the Y-axis adjuster and the base frame, which is not described herein again.

[0064] In the embodiment, the base frame, the Y-axis adjuster, the X-axis adjuster, the Z-axis adjuster, the motor and the permanent magnet 2 are sequentially connected. Alternatively, in other embodiments of the present application, the adjusters of the adjusting assembly can also be sequentially connected in other modes, for example, the base frame, the X-axis adjuster, the Y-axis adjuster, the Z-axis adjuster, the motor and the permanent magnet 2 are sequentially connected, or the base frame, the Y-axis adjuster, the Z-axis adjuster, the X-axis adjuster, the motor and the permanent magnet 2 are sequentially connected. As long as the three adjusters of the adjusting assembly respectively control the movement of the permanent magnet in three perpendicular directions, the position adjustment of the permanent magnet in the three-dimensional space can be realized.

[0065] In the embodiment, the permanent magnet 2 and the lower end of the rotating shaft 4 of the motor are fixedly connected by, for example, a gluing mode. Alternatively, in other embodiments of the present application, the permanent magnet and the rotating shaft of the motor can also be fixedly connected by other existing modes, which are not listed herein.

[0066] In the embodiment, the adjusting assembly is used to adjust the position of the permanent magnet 2 in the space, and the motor is used to drive the permanent magnet 2 to rotate around the rotating axis parallel to the Z-axis direction. Alternatively, in other embodiments of the present application, the following settings can also be made:

[0067] For example, the motor is cancelled, and the permanent magnet is directly fixed at the lower end of the Z-axis adjuster. Of course, the magnetic field direction at the to-be-measured grain cannot be adjusted by rotating the permanent magnet, and therefore the technical solution 2 of the embodiment is preferred, in which the permanent magnet is installed by the motor, or the permanent magnet is rotatably installed at the lower end of the Z-axis adjuster by a manually operated rotating part. The permanent magnet is fixedly connected with the rotating part and rotates around the axis parallel to the Z-axis direction relative to the Z-axis adjuster. In this way, the magnetic field direction at the to-be-measured grain can be adjusted by manually rotating the permanent magnet / rotating part. Of course, this is not conducive to automatically operating the rotation of the permanent magnet, and therefore the technical solution of the embodiment is preferred, in which the permanent magnet is installed by the motor.

[0068] For another example, the adjusting assembly is cancelled, and the shell of the motor is directly fixed on the base frame. Of course, this is not conducive to realizing the position adjustment of the permanent magnet, and the adaptability to the needle card and the to-be-measured grain is weak. Therefore, the technical solution of the embodiment with the adjusting assembly is preferred.

[0069] For example, the adjusting assembly and the motor are cancelled, and the permanent magnet is directly installed on the base frame. Of course, this is not conducive to the adjustment of the position of the permanent magnet and the rotation position of the permanent magnet by the motor, and thus the technical solution with the adjusting assembly and the motor is preferred.

[0070] Finally, it should be emphasized that the above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wafer testing apparatus for testing the magnetoelectric properties of a die on a wafer under test, comprising a base, a permanent magnet, and a pin holder fixedly mounted on the base, wherein the thickness direction of the pin holder is parallel to the vertical direction and has a probe extending below it; During testing, the wafer to be tested is placed below the probe card with its thickness direction parallel to the vertical direction, the die to be tested is located in the magnetic field environment of the permanent magnet, and the probe is electrically connected to the die to be tested. Its features are: The needle card has a first hole, and the position of the first hole is directly opposite the position of the probe in the vertical direction. The permanent magnet extends at least partially into the first hole from top to bottom.

2. The wafer testing apparatus according to claim 1, characterized in that: The first hole passes through the pin clip; The size of the lower end opening of the first hole is less than or equal to the size of the upper end opening of the first hole. The probe passes through the hole wall of the lower end opening and extends downwards from the lower end opening.

3. The wafer testing apparatus according to claim 1, characterized in that: The pin clip includes a circuit board and an insulating layer fixed to the lower side wall of the circuit board, and the probe extends through the insulating layer and extends below the pin clip; The first hole passes through the circuit board of the pin card, or the first hole passes through the circuit board and the insulating layer.

4. The wafer testing apparatus according to claim 3, characterized in that: The first hole has an upper hole section located on the circuit board and a lower hole section located on the insulating layer, with the permanent magnet extending at least partially into the lower hole section.

5. The wafer testing apparatus according to claim 1, characterized in that: The vertical distance between the permanent magnet and the wafer under test is greater than 1.4 mm and less than 4.4 mm, or equal to 1.4 mm, or equal to 4.4 mm; The thickness of the circuit board of the pin card is greater than or equal to 5 mm.

6. The wafer testing apparatus according to claim 1, characterized in that: The pin clip is detachably mounted to the base frame by fastening pins; The circuit board of the pin card has a countersunk hole that runs vertically through it. The fastening pin passes through the countersunk hole from bottom to top and is connected to the base frame. At least part of the head of the fastening pin is submerged in the countersunk hole.

7. The wafer testing apparatus according to any one of claims 1-6, characterized in that: The permanent magnet is mounted on the base frame via an adjustment assembly, which is used to adjust the position of the permanent magnet. The adjustment assembly includes a first adjuster, a second adjuster, and a third adjuster. The first adjuster is used to adjust the position of the permanent magnet in the vertical direction, the second adjuster is used to adjust the position of the permanent magnet in the second direction, and the third adjuster is used to adjust the position of the permanent magnet in the third direction. The vertical direction, the second direction, and the third direction are all perpendicular to each other.

8. The wafer testing apparatus according to any one of claims 1-6, characterized in that: The permanent magnet is rotatably disposed relative to the base frame, and there is an angle between the rotation axis of the permanent magnet and the magnetic pole distribution direction of the permanent magnet, so as to adjust the magnetic field direction at the grain to be tested by rotating the permanent magnet.

9. The wafer testing apparatus according to claim 8, characterized in that: The rotation axis of the permanent magnet is in the vertical direction; The magnetic pole distribution direction of the permanent magnet is perpendicular to the rotation axis; The permanent magnet is mounted on the base frame via a rotating component, and the permanent magnet is fixed to the lower end of the rotating component; The rotating component is the shaft of the motor; The permanent magnet is in the shape of a ring or a disk, the center line of the permanent magnet coincides with the axis of rotation, and the magnetization direction of the permanent magnet is radial. The maximum distance from the rotation axis to the outer contour of the permanent magnet is L, where 3.5 mm ≤ L ≤ 4.5 mm.

10. The wafer testing apparatus according to claim 8, characterized in that: The permanent magnet is a multi-pole magnetic ring, and the ring body of the multi-pole magnetic ring is directly opposite the probe in the vertical direction.

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