Ultralow-temperature full-automatic photoelectric probe station
By combining an inverted structure with an automated optical image acquisition system, the problem that existing low-temperature probe station systems cannot meet the requirements of ultra-low temperature testing of superconducting devices has been solved, enabling efficient and accurate mass testing and improving the yield and testing efficiency of superconducting devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2026-04-03
AI Technical Summary
Existing cryogenic probe station systems cannot meet the cryogenic testing requirements of superconducting devices, and are difficult to operate, resulting in low testing efficiency, easy damage to samples, and inability to achieve large-scale, efficient, and accurate performance calibration.
An ultra-low temperature fully automated photoelectric probe station was designed. It adopts an inverted structure and combines a closed helium gas circulation to promote the flow of liquid helium by gravity, thereby increasing the thermal utilization efficiency. It also achieves precise probe positioning and testing through an automated optical image acquisition system, supporting efficient and accurate testing of large batches of devices.
It enables efficient and accurate testing of large batches of devices in ultra-low temperature environments, shortens the testing cycle, improves the yield and testing efficiency of superconducting devices, avoids sample damage, and is suitable for the large-scale mass production of superconducting devices.
Smart Images
Figure CN224081687U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of automated low-temperature testing devices for semiconductors and quantum chips, specifically relating to an ultra-low temperature fully automated photoelectric probe station. Background Technology
[0002] Probe stations are critical devices used for rapid testing and performance screening before chip packaging. Room-temperature probe stations have become mainstream equipment in the semiconductor industry. However, the demand for cryogenic probe stations has emerged to address the need for labeling novel devices requiring low-temperature processes, such as quantum chips, superconducting single-photon detectors, and two-dimensional materials.
[0003] Recent research has shown that electronic devices exhibit superior performance and new physical phenomena at low temperatures. Therefore, research on low-temperature electronic devices has become a hot topic. The most mainstream applications are superconducting nanowire devices, including Josephson junctions (a crucial component of quantum computing), superconducting single-photon detectors, and superconducting digital circuits. These largely have well-established industry chains, requiring large-scale screening of devices at low temperatures. Low-temperature probe systems can significantly improve the efficiency of screening for high-quality devices. CMOS devices at low temperatures also exhibit different electrical characteristics compared to those at room temperature. Therefore, research on low-temperature CMOS devices also requires the use of low-temperature probe systems to characterize the electrical performance of the chips at low temperatures.
[0004] Furthermore, research on emerging two-dimensional materials and other novel material devices also relies on cryogenic environments. At low temperatures, two-dimensional materials such as graphene and transition metal sulfides exhibit unique physical properties, including the quantum Hall effect and superconductivity. Research on these new materials at low temperatures not only reveals their fundamental physical properties but also explores their application potential in electronic devices. In conclusion, providing a stable cryogenic environment offers ideal conditions for the research of various electronic devices and materials, driving innovation and development.
[0005] In recent years, China's cryogenic refrigeration technology has developed rapidly, and it now has the capability to mass-produce 1.5K cryostats. However, due to the limited space of cryogenic cryostats, only a limited number of cryogenic coaxial cables and optical fibers can be accommodated, which limits the number of cryogenic electronic devices that can be tested in a single cycle. When dealing with large quantities of cryogenic electronic devices, multiple cycles of cooling and sample replacement are required, which greatly limits testing efficiency.
[0006] While existing vacuum high and low temperature probe systems can measure more cryogenic devices under high and low temperature conditions by moving the probe to reduce the number of cooling cycles, their operating temperature cannot meet the ultra-low temperature requirements of superconducting devices. Furthermore, moving the probe to change test devices is difficult and inefficient, and the operation can easily scratch the wafer surface, further affecting wafer testing. In practical use, it is impossible to efficiently and accurately calibrate the performance of superconducting devices. Utility Model Content
[0007] One of the objectives of this invention is to provide an ultra-low temperature probe station testing platform to solve the problem that superconducting devices cannot be tested before packaging, reduce the workload of staff, improve the testing efficiency of superconducting devices, increase the yield of superconducting devices, and realize the large-scale mass production and testing of superconducting devices.
[0008] The second objective of this invention is to provide a visual superconducting device testing and characterization platform. The superconducting material characterization platform consists of a cooling platform, a sample stage, a probe support structure, an optical image acquisition system, a heat shield, an optical observation hole, etc., and can observe the condition inside the low-temperature cavity through an optical microscope.
[0009] The third objective of this utility model is to provide an automated testing system with advantages such as high precision, convenient operation, high efficiency, and high positioning accuracy. It can avoid the problem of damage to samples caused by insufficient operator proficiency, and at the same time achieve efficient and accurate testing of large batches of samples.
[0010] To achieve the above objectives, this utility model provides the following technical solution:
[0011] An ultra-low temperature fully automated photoelectric probe station includes a heat shield, a cooling platform disposed within the heat shield, a sample stage and a probe support structure, and an optical image acquisition system disposed outside the heat shield. The sample stage includes a cooling copper block and a stage. The upper end of the cooling copper block is fixed to the cooling platform, and the stage is inverted and installed below the cooling copper block. The probe support structure is disposed around the sample stage, with its upper end fixed to the cooling platform and its lower end inverted and fitted with a probe via a displacement device. A first optical observation hole is provided on the lower wall of the heat shield. The probe station adopts an inverted structure, with the overall structure extending downward from the inverted cooling platform. The optical image acquisition system observes the sample and probe status inside the heat shield from below through the first optical observation hole.
[0012] Furthermore, the probe support structure includes a support rod, a tray, a displacement device, and a U-shaped probe support frame. The upper end of the support rod is fixed to the cooling platform, and the lower end is connected to the tray. The displacement device is fixed to the upper side of the tray, and a U-shaped probe support frame is fixedly installed above the displacement device. The probe is installed upside down on the inner end of the U-shaped probe support frame, and the test port of the probe faces upward to contact the sample on the stage. A counterweight is fixedly installed on the outer end of the U-shaped probe support frame.
[0013] Furthermore, it also includes a copper braided cold chain, with the upper side of the zigzag probe support fixed to the lower end of the copper braided cold chain, and the upper end of the copper braided cold chain fixedly connected to the sample stage.
[0014] Furthermore, the heat shield includes three layers, namely a first aluminum alloy shield, a second aluminum alloy shield, and a cast iron shield, from the inside out. Several second optical observation holes are opened circumferentially on the side wall of the heat shield.
[0015] Furthermore, an aperture is provided at the first optical observation hole, and the optical image acquisition system is fixed on the optical platform and positioned below the aperture.
[0016] Furthermore, the aperture includes a strong magnet, an O-ring, a housing, a micro motor, and grating blades. The housing of the aperture is attracted to the heat shield by the strong magnet, and the connection is sealed with an O-ring. The aperture controls the opening and closing of the grating blades by the micro motor.
[0017] Furthermore, the optical image acquisition system includes an optical magnification structure, an image acquisition camera, a mechanical mounting frame, a high-precision displacement device, and a sliding guide rail. The three sets of high-precision displacement devices and the sliding guide rail form a three-dimensional moving system that can move along the horizontal XY direction and rise and fall along the vertical Z-axis. The optical magnification structure and the image acquisition camera are mounted on the three-dimensional moving system through the mechanical mounting frame. The optical magnification structure is located below the first optical observation hole, and the image acquisition camera is located behind the optical magnification structure and is connected to the displacement device signal inside the heat shield.
[0018] Furthermore, the optical magnification structure adopts a light-bending structure and has a built-in supplementary light source in the optical path.
[0019] Furthermore, the stage and the cooling copper block are detachably connected.
[0020] Furthermore, the cooling copper block is connected to the stage via an indium sheet.
[0021] Compared with the prior art, the beneficial effects of this utility model are:
[0022] This invention relates to a fully automated ultra-low temperature photoelectric probe station. By employing an inverted structure, it transforms the existing top-down detection method into a bottom-up one, thus fully adapting to the closed-loop helium circulation principle within the cooling platform. This allows for better utilization of gravity to promote liquid helium flow, increasing heat utilization efficiency. Simultaneously, the inverted probe station structure enables the displacement device and probe to be designed with a larger range of motion, thereby increasing the number of chips that can be tested in a single cycle. This invention enables efficient and accurate testing of large batches of devices in an ultra-low temperature (1.5K) environment. It can complete the testing of a large number of superconducting devices in a single cooling cycle, significantly shortening the testing cycle. Attached Figure Description
[0023] Figure 1 This is an overall structural diagram of the probe station of this utility model;
[0024] Figure 2 This is a schematic diagram of the sample stage structure in this utility model;
[0025] Figure 3 This is a schematic diagram of the probe support structure in this utility model;
[0026] Figure 4 This is a schematic diagram of the heat shield structure in this utility model;
[0027] Figure 5 This is a schematic diagram of the image acquisition structure in this utility model.
[0028] The diagram shows the following markings: 1-Cooling platform; 2-Sample stage; 3-Probe support structure; 4-Optical image acquisition system; 5-Heat shield; 6-Optical observation hole; 7-Aperture; 101-Electrical adapter; 201-Cooling copper block; 202-Removable stage; 301-Support rod; 302-Tray; 303-Displacement device; 304-Z-shaped probe support frame; 305-Test probe; 306-Elliptical counterweight; 307-Copper braided cold chain; 401-Optical magnification structure; 402-CCD high-definition acquisition camera; 403-Mechanical fixing frame; 404-High-precision displacement device; 405-Sliding guide rail; 406-Light source; 501-First aluminum alloy shield; 502-Second aluminum alloy shield; 503-Cast iron shield. Detailed Implementation
[0029] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, specific embodiments are now described with reference to the accompanying drawings. In this utility model, terms indicating direction such as front, back, left, and right are all used to describe... Figure 1 Use the front, back, left, and right as references.
[0030] The structure of this novel fully automated ultra-low temperature photoelectric probe station is as follows: Figure 1 As shown, this utility model is an ultra-low temperature fully automatic photoelectric probe station, mainly comprising a cooling platform 1, a sample stage 2, a probe support structure 3, an optical image acquisition system 4, a heat shield 5, and an optical observation hole 6. The cooling platform 1 is the uppermost structure. Below the cooling platform 1, from the center of the bottom surface of the cooling platform 1 outwards, are the sample stage 2, the probe support structure 3, the electrical adapter interface 101, the heat shield 5, etc., arranged sequentially. The optical image acquisition system 4 is installed below the cooling platform 1. The probe station adopts an inverted structure, with the overall structure extending downwards from the center of the cooling unit. The optical image acquisition system allows observation of the sample inside the heat shield and the probe status from below through the optical observation hole.
[0031] In this utility model, the sample stage 2 is as follows: Figure 2 As shown, the sample stage 2 is inverted and mounted at the center of the cooling platform 1. The cooling platform 1 is mainly equipped with a liquid helium refrigerator for cryogenic cooling. The cooling platform 1 also supports and fixes other platforms. The sample stage 2 includes a cooling copper block 201 and a detachable stage 202. The cooling copper block 201 is fixed at the center of the cooling platform 1 to store cold energy and provide heat dissipation for the detachable stage 202. The detachable stage 202 is inverted and mounted below the cooling copper block 201 and fixed to the cooling copper block 201 with screws. The cooling copper block 201 and the detachable stage 202 are connected by an indium sheet to improve thermal conductivity. The wafer under test is mounted on the stage from bottom to top using a fixing clamp. Due to the inverted structure design of the probe station, the displacement device and probe have a larger range of movement, thus increasing the number of chips contained in a single wafer. For example, existing testing methods that do not use probe stations require large electrode structures for chip testing, which need to be cut open. Testing can only be done by gold wire bonding. Therefore, the single wafer used usually contains only 4*4=16 chips, which is inefficient. However, this invention uses a probe station with a displacement device and probes with a large range of movement. A single wafer can contain 26*26*2=1352 chips, thereby greatly improving the efficiency of a single test.
[0032] The probe support structure 3 in this utility model is as follows: Figure 3As shown, the probe support structure 3 is located on the outside of the sample stage 2 and is evenly distributed in four mutually perpendicular directions around the sample stage 2. The probe support structure 3 includes a support rod 301, a tray 302, a displacement device 303, a Z-shaped probe support frame 304, a test probe 305, and an elliptical counterweight 306. The upper end of the support rod 301 is fixed to the cooling platform 1, and the lower end is connected to the tray 302 by screws. The displacement device 303 is fixed to the upper side of the tray 302 by screws. The displacement device 303 can realize full-space displacement in three degrees of freedom. The Z-shaped probe support frame 304 is fixed to the displacement device 303 by screws. A test probe 305 is mounted upside down on the inner side of the Z-shaped probe support frame 304, with its test port facing upwards to contact the chip on the stage. An elliptical counterweight 306 is mounted on the outer side of the Z-shaped probe support frame 304, and is fixed to the Z-shaped probe support frame 304 by screws. The elliptical counterweight 306 and the test probe 305 form two stable torques through weight and force, ensuring the stability of the test probe 305. The upper side of the Z-shaped probe support frame 304 is fixed to the lower end of the copper braided cold chain 307 by screws, and the upper end of the copper braided cold chain 307 is fixed to the sample stage 2 by screws. The copper braided cold chain 307 serves to transfer heat.
[0033] The heat shield 5 in this utility model is as follows: Figure 4 As shown, the outermost part of the probe support structure 3 is a heat shield 5, which consists of three layers: a first aluminum alloy shield 501, a second aluminum alloy shield 502, and a cast iron shield 503, providing shielding at 4K, 40K, and 300K respectively. The heat shield 5 provides thermal insulation for the sample stage at different temperatures and maintains an ultra-low vacuum environment. Four optical observation holes 6 are provided on the heat shield 5. Three of these are horizontal observation ports located on the sides of the heat shield 5, arranged at angles of 90°, 180°, and 270°. The fourth observation port is a vertical observation port located at the bottom of the heat shield 5. Below the vertical observation port is an automatically closing aperture 7. The aperture 7 includes a strong neodymium magnet, an O-ring, a housing, a micro motor, and grating blades. The housing of the aperture 7 is attracted to the heat shield 5 by the strong neodymium magnet, and the connection is sealed by the O-ring to prevent contamination by external light signals. The aperture 7 controls the micro motor through a microcontroller, which in turn controls the grating blades to open and close automatically.
[0034] The optical image acquisition system 4 in this utility model is as follows: Figure 5As shown, the optical image acquisition system 4 is located below the heat shield 5. The optical image acquisition system 4 includes an optical magnification structure 401, a CCD high-definition acquisition camera 402, a mechanical mounting bracket 403, a high-precision displacement device 404, a sliding guide rail 405, and a light source 406. The three sets of high-precision displacement devices 404 and the sliding guide rail 405 form a three-dimensional movement system capable of horizontal XY-axis movement and vertical Z-axis lifting. The optical image acquisition system achieves fine adjustment control of the focus by moving up and down, enabling image acquisition at different fields of view and distances. The optical image acquisition system 4 achieves fine scanning control of different position ranges by moving forward, backward, left, and right. Data fed back from the CCD high-definition acquisition camera 402 controls the displacement device 303 within the heat shield, achieving precise probe movement in low-temperature environments. With image-assisted positioning, micron-level precise control can be achieved. To achieve image acquisition from different positions, the optical magnification structure 401 is horizontally mounted on the three-dimensional moving system via a mechanical mounting bracket 403. The optical magnification structure 401 adopts a 90° light-bending structure, which shortens the optical axis distance by changing the light propagation path. The optical image acquisition system 4 is closer to the bottom of the heat shield 5, which helps to reduce the size of the device. In addition, the optical image acquisition system 4 has its own light source 406 for supplementary lighting, which can observe the surface of the chip on the stage under relatively dark conditions. The sliding guide rail 405 is fixed on the optical platform, which can meet the requirements of low vibration, and the vibration amplitude can be controlled within 100μm.
[0035] This utility model relates to a fully automated ultra-low temperature photoelectric probe stage, employing an inverted structure adapted to a closed-loop helium circulation cryogenic refrigerator. It achieves ultra-low temperatures while exhibiting low vibration. A piezoelectric displacement probe enables automated measurement and precise optical alignment; a 90-degree angled microscopic optical system enables inverted imaging, reduces bottom space height, and increases bottom space utilization. By combining image acquisition technology with automated displacement stage control, high-precision probe positioning and automated testing and characterization under ultra-low temperature conditions can be achieved. This avoids the need for repeated manual probe movement during the testing of large array devices, facilitating large-scale testing and characterization applications and enabling large-scale chip selection.
[0036] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A fully automated cryogenic opto-prober station, characterized in that, The application relates to a probe support structure and a cooling system for a probe support structure.
2. The fully automated ultra-low temperature photoprobe stage of claim 1, wherein, The probe support structure comprises a support rod, a tray, a displacer and a U-shaped probe support frame, the upper end of the support rod is fixed to the cooling platform, the lower end of the support rod is connected with the tray, the displacer is fixed to the upper side of the tray, the U-shaped probe support frame is fixedly installed above the displacer, the inner end of the U-shaped probe support frame is reversely provided with a probe, the test port of the probe faces upwards and contacts a sample on the sample stage, and the outer end of the U-shaped probe support frame is fixedly provided with a counterweight.
3. The fully automated ultra-low temperature photoprobe stage of claim 2, wherein, The application further relates to a copper-coding cooling chain, the upper side of the U-shaped probe support frame is fixed to the lower end of the copper-coding cooling chain, and the upper end of the copper-coding cooling chain is fixedly connected with the sample stage.
4. The fully automated cryogenic photoprobe station according to claim 1, wherein, The heat shielding cover comprises three layers, from inside to outside, a first aluminum alloy shielding cover, a second aluminum alloy shielding cover and a cast iron shielding cover, and a plurality of second optical observation holes are formed in the circumferential wall of the heat shielding cover.
5. The fully automated cryogenic photoprobe station according to claim 1, wherein, The optical image acquisition system is fixed on an optical platform and arranged below the diaphragm.
6. The fully automated cryogenic photoprobe station according to claim 5, characterized in that The diaphragm comprises a strong magnet, an O-shaped ring, a shell, a micro motor and grating blades, the shell of the diaphragm is attracted to the heat shielding cover through the strong magnet, the connection position is provided with the O-shaped ring for sealing, and the diaphragm controls the opening and closing of the grating blades through the micro motor.
7. The fully automated cryogenic photoprobe station according to claim 1, wherein, The optical image acquisition system comprises an optical amplification structure, an image acquisition camera, a mechanical fixing frame, high-precision displacers and sliding rails, three sets of high-precision displacers and sliding rails form a three-dimensional movement system which can move along the horizontal XY direction and vertically lift along the Z axis, the optical amplification structure and the image acquisition camera are installed on the three-dimensional movement system through the mechanical fixing frame, the optical amplification structure is arranged below the first optical observation hole, the image acquisition camera is arranged behind the optical amplification structure and in signal communication with the displacer in the heat shielding cover.
8. The fully automated cryogenic photoprobe station according to claim 7, characterized in that, The optical amplification structure adopts a light ray folding angle structure and is provided with a supplementary light source in the light path.
9. The ultra-low temperature fully automated photoprobing station of claim 1, wherein, The sample stage and the cooling copper block are detachably connected.
10. The fully automated cryogenic photoprobe station according to claim 1 or 9, characterized in that The cooling copper block and the sample stage are connected through an indium sheet.