Wafer testing device

Abstract

A wafer testing device aims to improve positioning precision, detection sensitivity and adjustment efficiency of wafer testing and comprises a wafer bearing unit, a mercury liquid testing unit, a probe horizontal adjustment unit and a mercury leakage detection unit. The wafer bearing unit comprises a bearing mechanism and a bearing table, the bearing mechanism drives the bearing table to move through a transverse moving module and a rotary table module, the bearing table fixes a wafer through vacuum adsorption, and the wafer is taken and placed in cooperation with an ejector rod; the mercury liquid testing unit ensures that a testing probe is always aligned with a testing point through a testing point mistake-proof base, and capacitance testing is completed by combining a probe driving mechanism; the probe horizontal adjustment unit realizes rapid and accurate adjustment of the horizontal state of the probe by means of laser, a spectroscope, an identification plate and the like; and the mercury leakage detection unit adopts a camera and a light source which are obliquely arranged to efficiently detect the mercury leakage of the wafer. The device is accurate in positioning, sensitive in detection, efficient in adjustment and suitable for high-precision wafer test scenes.

Description

Technical Field

[0001] This invention relates to wafer testing technology, and more particularly to a wafer testing apparatus. Background Technology

[0002] With the continuous development of semiconductor technology, the integration density of wafers is increasing, placing higher demands on the accuracy and efficiency of wafer testing. Existing wafer testing equipment has shortcomings in areas such as test point positioning accuracy, mercury leak detection accuracy, and probe horizontal adjustment accuracy. For example, the limited adjustment accuracy of the test probe easily leads to misalignment between the test probe and the test point; mercury leak detection struggles to identify minute mercury leaks; and the horizontal adjustment efficiency of the test probe is low.

[0003] Therefore, in view of the shortcomings of the existing technology, it is necessary to design a wafer testing device to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a wafer testing device to improve the accuracy of test point positioning, the sensitivity of mercury leakage detection, and the efficiency of test probe horizontal adjustment.

[0005] To achieve the above and other related objectives, the technical solution provided by the present invention is: a wafer testing device, comprising:

[0006] A wafer carrier unit includes a carrier mechanism and a carrier stage, wherein the carrier mechanism is used to drive the carrier stage to move, and the carrier stage is used to carry a wafer;

[0007] The mercury liquid testing unit comprises a test point error-proofing base, a probe driving mechanism, a test probe, and a mercury liquid testing system. The probe driving mechanism is fixed on the test point error-proofing base and is used to drive the test probe to test the wafer. The test point error-proofing base is configured to control the test end of the test probe to always face the test point on the wafer. The test probe is connected to the mercury liquid testing system for capacitance testing.

[0008] The probe horizontal adjustment unit includes a beam splitter, a laser emitter, a marker plate, and a silicon strip. The support platform has a light-transmitting hole. The silicon strip is located on the bottom side of the test probe and above the light-transmitting hole. The beam splitter is located below the light-transmitting hole. The laser emitter is located below the beam splitter. The marker plate is located outside the beam splitter. This unit is used to achieve horizontal adjustment of the probe.

[0009] The mercury leakage detection unit includes a camera and a light source. The camera and the light source are both located on the side of the support stage and tilted towards the support stage, and are used to detect whether there is mercury leakage on the wafer.

[0010] A preferred technical solution is as follows: the supporting mechanism includes a transverse module, a base plate, and a turntable module, wherein the base plate and the turntable module are disposed at the moving end of the transverse module, and the supporting platform is disposed at the rotating end of the turntable module.

[0011] A preferred technical solution is as follows: the support platform has a vacuum chamber inside, the vacuum chamber is connected to an external vacuum adsorption system, and the top side of the support platform has an adsorption hole that is connected to the vacuum chamber.

[0012] The preferred technical solution is as follows: the test point error-proof base consists of a fixed base, a movable base, and steel balls. The fixed base and the movable base have similar structures, both being seat structures with a concave center and flat sides. The movable base is embedded in the fixed base. The fixed base has a steel ball groove 1 on the top side of its left ear, and the movable base has a steel ball groove 2 on the bottom side of its left ear. The steel ball groove 1 and the steel ball groove 2 are correspondingly matched. The steel ball is placed in the limiting structure formed by the steel ball groove 1 and the steel ball groove 2. The fixed base has a stepped hole 1 on its left ear and a stepped hole 2 on its right ear. The movable base has a screw hole 1 on its left ear and a screw hole 2 on its right ear. The stepped hole 1 and the screw hole 1 are correspondingly matched and connected by a bolt 1. The stepped hole 2 and the screw hole 2 are correspondingly matched and connected by a bolt 2.

[0013] The preferred technical solution is that, in the assembled state, the center of the steel ball is on the detection surface of the wafer.

[0014] A preferred technical solution is as follows: the probe driving mechanism adopts a telescopic electric cylinder, and the test probe is connected to the driving end of the probe driving mechanism through a cantilever; the probe driving mechanism is configured to drive the test probe to move up and down along the radial direction of the steel ball.

[0015] The preferred technical solution is as follows: a mounting base is provided on the substrate, the beam splitter is assembled in the mounting base and is inclined at 45°, the laser emitter is fixed in the mounting base and the emitting end is vertically upward, the marking plate is fixed on one side of the mounting base and is used to receive the refracted light spot, and the marking plate is provided with a grid-like marking for marking the position of the light spot.

[0016] The preferred technical solution is as follows: the camera is fixed to the side of the support platform by a bracket, and the camera is set at an angle of 30°-45° with the platform surface; the light source is fixed on the bracket in an adjustable manner, and the light source is set at an angle of 10°-30° with the platform surface.

[0017] A preferred technical solution is as follows: a baffle is fixedly provided on the bottom side of the support platform, and a U-shaped photoelectric sensor is fixedly provided on the substrate, with the baffle and the U-shaped photoelectric sensor being arranged correspondingly.

[0018] A preferred technical solution is as follows: a lifting module is fixed on the substrate, the lifting module is used to drive the arc-shaped connector to lift and lower, a circular lifting component is fixed on the top side of the arc-shaped connector, a plurality of top rods are provided on the top side of the circular lifting component, a plurality of through holes are provided on the support platform, and the plurality of through holes and the plurality of top rods are arranged in a one-to-one correspondence for lifting the wafer assembled on the support platform.

[0019] Due to the application of the above technical solution, the beneficial effects of this invention are as follows:

[0020] High test point positioning accuracy: Through the cooperation structure of the fixed seat, movable seat and steel ball of the test point error prevention base, the limiting effect of the steel ball and the adjustment function of the bolt can ensure that the test end of the test probe is always accurately facing the test point on the wafer, effectively reducing alignment deviation.

[0021] High sensitivity of mercury leakage detection: The mercury leakage detection unit uses a tilted camera and light source. The light source can provide sufficient and appropriately angled illumination, and the camera can clearly capture tiny mercury leakage traces on the wafer surface, improving the accuracy of mercury leakage detection.

[0022] Highly efficient horizontal adjustment of the test probe: The probe horizontal adjustment unit emits a laser through a laser emitter, which is refracted by a beam splitter and then shines onto the marking plate. Combined with the blocking or reflection of the laser by the silicon strip, the horizontal state of the test probe can be quickly determined. Precise adjustment is achieved through the grid-like markings, improving adjustment efficiency.

[0023] Stable wafer support and convenient operation: The support stage achieves vacuum adsorption of the wafer through a vacuum chamber and adsorption holes, ensuring that the wafer remains stable and does not shift during testing; at the same time, the lifting module drives the top rod to lift the wafer, facilitating wafer pick-up and drop operations.

[0024] Flexible and diverse motion adjustment: The transverse module and turntable module of the support mechanism can realize the horizontal movement and rotation of the support platform, respectively. Combined with the support of the substrate, the test position of the wafer can be flexibly adjusted to meet different test requirements. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the wafer testing apparatus of the present invention from one viewpoint.

[0026] Figure 2 This is a schematic diagram of the wafer testing apparatus of the present invention from another perspective. Detailed Implementation

[0027] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0028] Please see Figures 1-2 It should be noted that in the description of this invention, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. The terms "horizontal," "vertical," and "suspended," etc., do not indicate that the component must be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] Example:

[0031] like Figures 1 to 2 As shown, according to an overall technical concept of the present invention, a wafer testing apparatus is provided, comprising:

[0032] The wafer carrier unit includes a carrier mechanism 1 and a carrier stage 2. The carrier mechanism 1 is used to drive the carrier stage 2 to move, and the carrier stage 2 is used to carry the wafer.

[0033] The mercury liquid testing unit comprises a test point error-proof base 3, a probe driving mechanism 4, a test probe 5, and a mercury liquid testing system. The probe driving mechanism 4 is fixed on the test point error-proof base 3 and is used to drive the test probe 5 to test the wafer. The test point error-proof base 3 is configured to control the test end of the test probe 5 to always face the test point on the wafer. The test probe 5 is connected to the mercury liquid testing system to perform capacitance testing.

[0034] The probe horizontal adjustment unit includes a beam splitter 6, a laser emitter (not shown), an identification plate 7, and a silicon strip (not shown). The support platform 2 is provided with a light-transmitting hole 21. The silicon strip is located on the bottom side of the test probe 5 and above the light-transmitting hole 21. The beam splitter 6 is located below the light-transmitting hole 21. The laser emitter is located below the beam splitter 6. The identification plate 7 is located on the outside of the beam splitter 6 and is used to realize the horizontal adjustment of the probe.

[0035] The mercury leakage detection unit includes a camera 8 and a light source 9. Both the camera 8 and the light source 9 are located on the side of the support stage 2 and are tilted towards the support stage 2. They are used to detect whether there is mercury leakage on the wafer.

[0036] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, the support mechanism 1 includes a transverse module 11, a base plate 12 and a turntable module 13. The base plate 12 and the turntable module 13 are disposed at the moving end of the transverse module 11, and the support platform 2 is disposed at the rotating end of the turntable module 13.

[0037] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, the support platform 2 is provided with a vacuum chamber inside, the vacuum chamber is connected to an external vacuum adsorption system, and the top side of the support platform 2 is provided with an adsorption hole, which is connected to the vacuum chamber.

[0038] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, the test point error-proof base 3 is composed of a fixed base 31, a movable base 32, and a steel ball 33. The fixed base 31 and the movable base 32 have similar structures, both being seat structures with a concave middle and flat sides. The movable base 32 is embedded in the fixed base 31. The top side of the left ear of the fixed base 31 is provided with a steel ball groove 1, and the bottom side of the left ear of the movable base 32 is provided with a steel ball groove 2. The steel ball groove 1 and the steel ball groove 2 are matched and matched accordingly. The steel ball 33 is disposed in the limiting structure composed of the steel ball groove 1 and the steel ball groove 2. The left ear of the fixed base 31 is provided with a stepped hole 1, and the right ear is provided with a stepped hole 2. The left ear of the movable base 32 is provided with a screw hole 1, and the right ear is provided with a screw hole 2. The stepped hole 1 and the screw hole 1 are matched and matched accordingly and connected by a bolt 1. The stepped hole 2 and the screw hole 2 are matched and matched accordingly and connected by a bolt 2.

[0039] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, in the assembled state, the center of the steel ball 33 is in the same plane as the detection surface of the wafer.

[0040] like Figures 1 to 2As shown, in an exemplary embodiment of the present invention, the probe driving mechanism 4 employs a telescopic electric cylinder, and the test probe 5 is connected to the driving end of the probe driving mechanism 4 via a cantilever. The probe driving mechanism 4 is configured to drive the test probe 5 to move up and down along the radial direction of the steel ball 33. Specifically, the height of the center of the steel ball 33 is equal to the surface of the sample (wafer). The fixed base 31, the movable base 32, the probe driving mechanism 4, the cantilever, and the test probe 5 cooperate with each other to ensure that when the test probe 5 is extended and retracted by the probe driving mechanism 4, it moves up and down along the radius of the center of the steel ball 33. Thus, when it contacts the surface of the sample (wafer), it coincides exactly with the center of the steel ball 33. This ensures that after the test probe 5 tilts, the test point error-proof base 3 compensates for the tilt of the test probe 5, and the test probe 5 can still test the same point on the sample (wafer). Here, the steel ball 33 is the rotation center supporting the tilt of the probe system.

[0041] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, a mounting base 10 is provided on the substrate 12, a beam splitter 6 is assembled in the mounting base 10 and is inclined at 45°, a laser emitter is fixed in the mounting base 10 and the emitting end is vertically upward, and an identification plate 7 is fixed on one side of the mounting base 10 and is used to receive the refracted light spot. The identification plate 7 is provided with a grid-like mark for marking the position of the light spot. The operator can adjust the position of the test probe according to the position of the light spot.

[0042] During optically assisted leveling, a double-polished silicon wafer is first placed on the support stage 2. After being vacuum-attracted, the lower surface of the double-polished silicon wafer is aligned with the support stage 2. The laser beam passes through the light-transmitting hole on the support stage and illuminates the back of the double-polished silicon wafer. The reflected light spot passes through the light-transmitting hole on the support stage 2 again and is reflected and projected onto a reference point on the marker plate 7. Then, the double-polished silicon wafer is removed, and a leveling silicon strip is vacuum-attracted to the probe's test surface. The support stage 2 is moved so that the leveling laser beam illuminates the silicon strip adsorbed on the lower surface of the probe. The reflected laser spot passes through the light-transmitting hole on the support stage 2, is reflected by the beam splitter 6, and is projected onto the same point on the marker plate 7. In this way, the test surface of the test probe 5 is parallel to the support stage 2. Here, the laser emitter is pre-installed to ensure that after reflection from the double-polished silicon wafer on the support stage 2, it reaches the beam splitter 6. The emitted light spot and the reflected light spot on the surface of the beam splitter 6 coincide, so that the laser is perpendicular to the support stage 2, which can reduce the offset of the reflected light spot caused by changes in the distance to the reflective surface. The beam splitter 6 has its splitting surface facing upwards, and the splitting ratio can be 1:1 or 1:2, depending on the incident light intensity and reflectivity. The beam splitter needs to be thin to reduce ghosting and ensure leveling accuracy. The laser and laser lens assembly must work together to ensure the smallest possible spot size when the laser beam converges onto the marker plate 7 (for example, if using a focused beam, the converging distance should be adjusted to cover the entire optical path of the incident and reflected light), thus improving resolution.

[0043] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, the camera 8 is fixed to the side of the support platform 2 by a bracket 81, and the camera 8 is set at an angle of 30°-45° with the platform surface of the support platform 2; the light source 9 is fixed on the bracket 81 in an adjustable manner, and the light source 9 is set at an angle of 10°-30° with the platform surface of the support platform 2.

[0044] The illumination for mercury leakage detection is primarily based on the fact that SiC samples are transparent and have a thickness of 300 to 400 micrometers. Conventional supplementary lighting methods would allow the patterns on the stage to pass through the sample, interfering with imaging. Therefore, the light source 9 is placed below the camera 8 and grazes at a large angle to avoid interference from the back of the transparent sample (wafer) or the stage 2. To avoid imaging from reflected light from the front of the polished sample (wafer), the camera 8 is also placed at a large angle at the edge of the sample. This requires the detection area of ​​the test point to be within the optimal imaging range of the camera 8. Furthermore, considering the high surface tension of mercury beads, their spherical and mirror-like shape on the silicon wafer surface means that the light from a point source is divergent, and the divergence angle is even greater after reflection from the mercury bead surface, resulting in an image much smaller than the actual mercury bead. This can be addressed by arranging a surface light source along the edge of the sample (wafer) to increase the cross-section of the reflected light from the mercury bead and improve its detection capability. To reduce false positives, a comparison of pre-test and post-test photographs is used.

[0045] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, a baffle 22 is fixedly provided on the bottom side of the support platform 2, and a U-shaped photoelectric sensor 20 is fixedly provided on the substrate 12. The baffle 22 and the U-shaped photoelectric sensor 20 are correspondingly arranged to detect the position of the support platform 2.

[0046] like Figures 1 to 2 As shown, in an exemplary embodiment of the present invention, a lifting module 30 is fixed on the substrate 12. The lifting module 30 is used to drive the arc-shaped connector 40 to rise and fall. A circular lifting member 50 is fixed on the top side of the arc-shaped connector 40. Multiple sets of top rods 60 are provided on the top side of the circular lifting member 50. Multiple sets of through holes are provided on the support platform 2. The multiple sets of through holes are arranged in a one-to-one correspondence with the multiple sets of top rods 60, and are used to lift the wafer assembled on the support platform 2.

[0047] It should be noted that:

[0048] Therefore, the present invention has the following advantages:

[0049] High test point positioning accuracy: Through the cooperation structure of the fixed seat, movable seat and steel ball of the test point error prevention base, the limiting effect of the steel ball and the adjustment function of the bolt can ensure that the test end of the test probe is always accurately facing the test point on the wafer, effectively reducing alignment deviation.

[0050] High sensitivity of mercury leakage detection: The mercury leakage detection unit uses a tilted camera and light source. The light source can provide sufficient and appropriately angled illumination, and the camera can clearly capture tiny mercury leakage traces on the wafer surface, improving the accuracy of mercury leakage detection.

[0051] Highly efficient horizontal adjustment of the test probe: The probe horizontal adjustment unit emits a laser through a laser emitter, which is refracted by a beam splitter and then shines onto the marking plate. Combined with the blocking or reflection of the laser by the silicon strip, the horizontal state of the test probe can be quickly determined. Precise adjustment is achieved through the grid-like markings, improving adjustment efficiency.

[0052] Stable wafer support and convenient operation: The support stage achieves vacuum adsorption of the wafer through a vacuum chamber and adsorption holes, ensuring that the wafer remains stable and does not shift during testing; at the same time, the lifting module drives the top rod to lift the wafer, facilitating wafer pick-up and drop operations.

[0053] Flexible and diverse motion adjustment: The transverse module and turntable module of the support mechanism can realize the horizontal movement and rotation of the support platform, respectively. Combined with the support of the substrate, the test position of the wafer can be flexibly adjusted to meet different test requirements.

[0054] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A wafer testing device, characterized in that, include: A wafer carrier unit includes a carrier mechanism and a carrier stage, wherein the carrier mechanism is used to drive the carrier stage to move, and the carrier stage is used to carry a wafer; The mercury liquid testing unit comprises a test point error-proofing base, a probe driving mechanism, a test probe, and a mercury liquid testing system. The probe driving mechanism is fixed on the test point error-proofing base and is used to drive the test probe to test the wafer. The test point error-proofing base is configured to control the test end of the test probe to always face the test point on the wafer. The test probe is connected to the mercury liquid testing system for capacitance testing. The probe horizontal adjustment unit includes a beam splitter, a laser emitter, a marker plate, and a silicon strip. The support platform has a light-transmitting hole. The silicon strip is located on the bottom side of the test probe and above the light-transmitting hole. The beam splitter is located below the light-transmitting hole. The laser emitter is located below the beam splitter. The marker plate is located outside the beam splitter. This unit is used to achieve horizontal adjustment of the probe. The mercury leakage detection unit includes a camera and a light source. The camera and the light source are both located on the side of the support stage and tilted towards the support stage, and are used to detect whether there is mercury leakage on the wafer.

2. The wafer testing apparatus according to claim 1, characterized in that: The supporting mechanism includes a transverse module, a base plate, and a turntable module. The base plate and the turntable module are located at the moving end of the transverse module, and the supporting platform is located at the rotating end of the turntable module.

3. The wafer testing apparatus according to claim 1, characterized in that: The support platform has a vacuum chamber inside, which is connected to an external vacuum adsorption system. The top side of the support platform has an adsorption hole that is connected to the vacuum chamber.

4. The wafer testing apparatus according to claim 1, characterized in that: The test point error-proof base consists of a fixed base, a movable base, and steel balls. The fixed base and the movable base have similar structures, both being seat structures with a concave center and flat sides. The movable base is embedded in the fixed base. The fixed base has a steel ball groove 1 on the top side of its left ear, and the movable base has a steel ball groove 2 on the bottom side of its left ear. The steel ball groove 1 and the steel ball groove 2 are matched and matched accordingly. The steel ball is placed in the limiting structure formed by the steel ball groove 1 and the steel ball groove 2. The fixed base has a stepped hole 1 on its left ear and a stepped hole 2 on its right ear. The movable base has a screw hole 1 on its left ear and a screw hole 2 on its right ear. The stepped hole 1 and the screw hole 1 are matched and matched accordingly and connected by a bolt 1. The stepped hole 2 and the screw hole 2 are matched and matched accordingly and connected by a bolt 2.

5. A wafer testing apparatus according to claim 4, characterized in that: In the assembled state, the center of the steel ball is on the inspection surface of the wafer.

6. A wafer testing apparatus according to claim 4, characterized in that: The probe driving mechanism adopts a telescopic electric cylinder, and the test probe is connected to the driving end of the probe driving mechanism through a cantilever; the probe driving mechanism is configured to drive the test probe to move up and down along the radial direction of the steel ball.

7. A wafer testing apparatus according to claim 2, characterized in that: The substrate is provided with a mounting base, the beam splitter is assembled in the mounting base and is inclined at 45°, the laser emitter is fixed in the mounting base and the emitting end is vertically upward, the marking plate is fixed on one side of the mounting base and is used to receive the refracted light spot, and the marking plate is provided with a grid-like mark for marking the position of the light spot.

8. A wafer testing apparatus according to claim 1, characterized in that: The camera is fixed to the side of the support platform by a bracket, and the camera is set at an angle of 30°-45° with the platform surface; the light source is fixed on the bracket in an adjustable manner, and the light source is set at an angle of 10°-30° with the platform surface.

9. A wafer testing apparatus according to claim 2, characterized in that: A baffle is fixed to the bottom side of the support platform, and a U-shaped photoelectric sensor is fixed on the substrate. The baffle is arranged correspondingly to the U-shaped photoelectric sensor.

10. A wafer testing apparatus according to claim 2, characterized in that: A lifting module is fixed on the substrate. The lifting module is used to drive the arc-shaped connector to rise and fall. A circular lifting component is fixed on the top side of the arc-shaped connector. Multiple sets of top rods are provided on the top side of the circular lifting component. Multiple sets of through holes are provided on the support platform. The multiple sets of through holes and the multiple sets of top rods are arranged one-to-one to lift the wafer assembled on the support platform.

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