Chip test low-temperature system for helium liquefaction and recondensation

Abstract

The invention relates to the technical field of low-temperature system integration, in particular to a helium liquefaction and recondensation chip test low-temperature system which comprises a liquid helium test cavity, a pulse tube refrigerating machine and a helium tank, the pulse tube refrigerating machine comprises a refrigerating machine compressor, a refrigerating machine cold head and a refrigerating machine cold screen, and the refrigerating machine cold head is connected with a condensation heat exchanger. The liquid helium testing cavity and the condensing heat exchanger are located in the refrigerating machine cold screen, the refrigerating machine cold head is communicated with the liquid helium testing cavity through a cold helium return pipeline, and the condensing heat exchanger is communicated with the liquid helium testing cavity through a liquid helium return pipeline. The helium tank is connected with the refrigerator cold head through a pipeline. The liquid helium testing cavity is used for containing liquid helium to provide a soaking testing environment, the problem of electromagnetic interference is avoided, cold helium evaporated in the liquid helium testing cavity flows back into the liquid helium testing cavity from the liquid helium backflow pipeline after being condensed through the condensation heat exchanger, and zero evaporation of the liquid helium in the superconducting chip testing process is achieved. And long-term test requirements of large-scale superconducting chips can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of cryogenic system integration, and in particular to a chip testing cryogenic system for helium liquefaction and recondensation, which can be used for low-temperature testing of large-scale complex superconducting chips. Background Art

[0002] The testing process of large-scale complex superconducting chips requires a long-term, stable and non-magnetic 4.2K low-temperature environment. In order to meet the testing environment of large-scale complex superconducting chips, it is usually necessary to use a refrigerator to directly cool the chip or immerse the chip in a liquid helium environment for testing.

[0003] When using a refrigerator to directly cool the chip for testing, the refrigerator and the external environment will cause electromagnetic interference, resulting in excessive electromagnetic interference in the chip testing; the method of immersing the chip in a liquid helium environment for testing can avoid the electromagnetic interference problem, but liquid helium evaporates too quickly at room temperature, resulting in excessive liquid helium consumption. For future large-scale superconducting computer chip testing, the cost of using liquid helium is too high. Summary of the Invention

[0004] The present invention provides a low-temperature chip testing system for helium liquefaction and recondensation, which is used to solve the defects in the prior art that directly cooling the chip with a refrigerator or immersing the chip in a liquid helium environment for testing cannot meet the long-term testing requirements of large-scale superconducting chips.

[0005] The present invention provides a low-temperature system for chip testing with helium liquefaction and recondensation, comprising:

[0006] Liquid helium test chamber, used to contain liquid helium to provide an immersion test environment;

[0007] A pulse tube refrigerator comprises a refrigerator compressor, a refrigerator cold head and a refrigerator cold screen, wherein the refrigerator cold head is connected to a condensing heat exchanger, the liquid helium test chamber and the condensing heat exchanger are located within the refrigerator cold screen, the refrigerator cold head is connected to the liquid helium test chamber via a cold helium return line, and the condensing heat exchanger is connected to the liquid helium test chamber via a liquid helium return line;

[0008] A helium tank is connected to the cold head of the refrigerator through a pipeline.

[0009] According to a low-temperature chip testing system for helium liquefaction and recondensation provided by the present invention, a pre-cooling heat exchanger is wound around the outside of the cold head of the refrigerator.

[0010] According to the present invention, a low-temperature system for chip testing with helium liquefaction and recondensation is provided. The system further includes a magnetic shielding device for forming a low magnetic field environment inside the liquid helium test chamber.

[0011] According to a low-temperature system for chip testing with helium liquefaction and recondensation provided by the present invention, the magnetic shielding device includes a low-temperature magnetic shielding cover and a normal-temperature magnetic shielding cover. The low-temperature magnetic shielding cover is located in the liquid helium test chamber, and the normal-temperature magnetic shielding cover is outside the refrigerator cold screen.

[0012] According to a low-temperature chip testing system for helium liquefaction and recondensation provided by the present invention, the liquid helium testing chamber is provided with a superconducting chip testing insertion interface for plugging in a superconducting chip interconnection module. The superconducting chip interconnection module is provided with a long strip connector for connecting a superconducting chip to extend into the liquid helium testing chamber for testing the superconducting chip.

[0013] According to the present invention, a low-temperature system for chip testing for helium liquefaction and recondensation is provided. The liquid helium test chamber includes a liquid storage chamber and a plug-in chamber connected to the liquid storage chamber. The liquid storage chamber contains liquid helium, and the superconducting chip test insertion interface is provided at the end of the plug-in chamber. A reverse check device is provided at the superconducting chip test insertion interface to prevent gaseous helium from flowing out of the superconducting chip test insertion interface.

[0014] According to a low-temperature system for chip testing with helium liquefaction and recondensation provided by the present invention, the liquid storage cavity is connected to an exhaust pipeline, and an exhaust valve and a pressure sensor are provided on the exhaust pipeline.

[0015] According to the chip testing cryogenic system for helium liquefaction and recondensation provided by the present invention, the liquid storage cavity is further connected to a liquid infusion pipeline for adding liquid helium into the liquid storage cavity from the outside.

[0016] According to the low-temperature system for chip testing with helium liquefaction and recondensation provided by the present invention, a liquid helium electronic level gauge is provided inside the liquid storage cavity.

[0017] According to a chip testing cryogenic system for helium liquefaction and recondensation provided by the present invention, a helium pressure reducing valve and a flow controller are provided on the pipeline connecting the helium tank to the cold head of the refrigerator.

[0018] The present invention provides a low-temperature chip testing system with helium liquefaction and recondensation. The helium provided by the helium tank is pre-cooled step by step by a refrigerator cold head, and finally liquefied in a condensing heat exchanger. The liquefied liquid helium enters the liquid helium testing chamber through a liquid helium return line to provide a liquid helium immersion environment. The refrigerator cold head of the pulse tube refrigerator can also pre-cool the refrigerator cold screen, thereby ensuring the thermal insulation performance of the system. The superconducting chip is immersed in the liquid helium environment in the liquid helium testing chamber, and the evaporated cold helium gas is recondensed by the pulse tube refrigerator. The liquid helium environment can effectively avoid electromagnetic interference during the testing process. The evaporated cold helium gas in the liquid helium testing chamber reaches the condensing heat exchanger through the cold helium return line, and after recondensation, it flows back into the liquid helium testing chamber from the liquid helium return line, thereby achieving zero evaporation of liquid helium during the superconducting chip testing process. The low-temperature chip testing system with helium liquefaction and recondensation has a compact structure and has the advantages of zero evaporation of liquid helium, low electromagnetic interference, and ease of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a schematic structural diagram of the chip testing cryogenic system for helium liquefaction and recondensation provided by the present invention;

[0021] Figure 2 It is a structural schematic diagram of the liquid helium test chamber provided by the present invention.

[0022] Reference numerals:

[0023] 1. Liquid helium test chamber; 101. Superconducting chip test insertion interface; 102. Superconducting chip interconnection module; 103. Long strip connector; 104. Superconducting chip; 105. Liquid storage chamber; 106. Plug-in chamber; 107. Exhaust pipe; 108. Infusion pipe; 109. Liquid helium electronic level gauge; 2. Pulse tube refrigerator; 201. Refrigeration compressor; 202. Refrigeration cold head; 203. Refrigeration cold screen; 3. Condensing heat exchanger; 4. Cold helium return pipe; 5. Liquid helium reflux pipe; 6. Helium tank; 601. Helium pressure reducing valve; 602. Flow controller; 7. Pre-cooling heat exchanger; 8. Magnetic shielding device; 801. Low-temperature magnetic shielding cover; 802. Normal-temperature magnetic shielding cover. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting the embodiments of the present invention.

[0026] In describing the embodiments of the present invention, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of the present invention based on the specific circumstances.

[0027] In the embodiments of the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," or "above" a second feature may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," or "below" a second feature may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0028] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0029] The following combination Figure 1 and Figure 2 The specific structure and working principle of the chip testing low temperature system for helium liquefaction and recondensation of the present invention are described.

[0030] One embodiment of the present invention provides a low-temperature system for chip testing with helium liquefaction and recondensation, see Figure 1 As shown, it includes a liquid helium test chamber 1, a pulse tube refrigerator 2 and a helium tank 6, wherein the liquid helium test chamber 1 is used to hold liquid helium to provide an immersion test environment; the pulse tube refrigerator 2 includes a refrigerator compressor 201, a refrigerator cold head 202 and a refrigerator cold shield 203, the refrigerator cold head 202 is connected to a condensing heat exchanger 3, the liquid helium test chamber 1 and the condensing heat exchanger 3 are located in the refrigerator cold shield 203, the refrigerator cold head 202 is connected to the liquid helium test chamber 1 through a cold helium return line 4, and the condensing heat exchanger 3 is connected to the liquid helium test chamber 1 through a liquid helium return line 5; the helium tank 6 is connected to the refrigerator cold head 202 through a pipeline.

[0031] It is understandable that the chip testing low-temperature system for helium liquefaction and recondensation provided in this embodiment is a superconducting chip low-temperature testing system based on a refrigerator + liquid helium. When conducting a test, first, vacuum treatment is performed using an external vacuum pump, and a high vacuum is maintained by a static sealing structure. The helium tank 6 and the pulse tube refrigerator 2 are turned on. The helium in the helium tank 6 is pre-cooled step by step under the action of the refrigerator cold head 202, and finally liquefied in the condensing heat exchanger 3. The liquefied liquid helium enters the liquid helium test chamber 1 through the liquid helium return line 5 to provide a liquid helium immersion environment. The refrigerator cold head 202 of the pulse tube refrigerator 2 can also pre-cool the refrigerator cold shield 203, thereby ensuring the thermal insulation performance of the system. The superconducting chip is immersed in the liquid helium environment in the liquid helium test chamber 1, and the evaporated cold helium is recondensed by the pulse tube refrigerator 2. The liquid helium environment can effectively avoid electromagnetic interference during the testing process. The cold helium gas evaporated in the liquid helium test chamber 1 reaches the condensing heat exchanger 3 through the cold helium return pipe 4. After being recondensed, it flows back into the liquid helium test chamber 1 through the liquid helium return pipe 5, thereby achieving zero evaporation of liquid helium during the superconducting chip testing process.

[0032] In some embodiments, in a low-temperature chip testing system for helium liquefaction and recondensation according to the present invention, a pre-cooling heat exchanger 7 is provided around the exterior of the refrigerator cold head 202. Specifically, a GM pulse tube refrigerator can be used, wherein the refrigerator cold head 202 comprises a primary cold head and a secondary cold head. The pre-cooling heat exchanger 7 is provided around the primary cold head, the secondary cold head, and the refrigerator cylinder wall. The condensing heat exchanger 3 is connected to the secondary cold head. After being fully pre-cooled by the multi-stage pre-cooling heat exchanger 7, room-temperature helium enters the condensing heat exchanger 3 connected to the secondary cold head for liquefaction.

[0033] In other embodiments, the present invention further includes a low-temperature system for chip testing using helium liquefaction and recondensation, and a magnetic shielding device 8 for forming a low-magnetic field environment within the liquid helium test chamber 1. Specifically, the magnetic shielding device 8 includes a low-temperature magnetic shielding cover 801 and a room-temperature magnetic shielding cover 802. The low-temperature magnetic shielding cover 801 is located within the liquid helium test chamber 1, and the room-temperature magnetic shielding cover 802 is located outside the refrigerator cold shield 203. The combined magnetic shielding structure of the room-temperature magnetic shielding cover 802 and the low-temperature magnetic shielding cover 801 forms an efficient magnetic shielding structure to ensure a low-magnetic field environment for chip testing.

[0034] In some further embodiments, a liquid helium test chamber 1 of a cryogenic system for chip testing using helium liquefaction and recondensation according to the present invention is provided with a superconducting chip test insertion interface 101 for receiving a superconducting chip interconnect module 102. Superconducting chip interconnect module 102 is provided with an elongated connector 103 for connecting to a superconducting chip 104, which is inserted into liquid helium test chamber 1 for superconducting chip testing. The provision of superconducting chip test insertion interface 101 allows for hot-swappability of superconducting chip 104 via superconducting chip interconnect module 102 through an external control program, ensuring that superconducting chip 104 can be replaced without system downtime.

[0035] Specifically, for some examples, see Figure 2As shown, the liquid helium test chamber 1 includes a liquid holding chamber 105 and a plug-in chamber 106 connected to the liquid holding chamber 105. The liquid holding chamber 105 holds liquid helium. A superconducting chip test insertion interface 101 is provided at the end of the plug-in chamber 106. A reverse check device is provided at the superconducting chip test insertion interface 101 to prevent gaseous helium from flowing out of the superconducting chip test insertion interface 101. When performing chip testing, the superconducting chip interconnection module 102 is connected to the superconducting chip 104 through the long strip connector 103, and the superconducting chip 104 is inserted from the superconducting chip test insertion interface 101. The superconducting chip 104 finally reaches the low-temperature magnetic shielding cover 801. The superconducting chip interconnection module 102 is located at the superconducting chip test insertion interface 101. The low-temperature magnetic shielding cover 801 cooperates with the liquid helium in the liquid holding cavity 105 to provide an extremely low magnetic liquid helium immersion environment. The superconducting chip interconnection module 102 can perform the hot-swap function of the superconducting chip 104 test through an external control program. When the superconducting chip 104 needs to be replaced, it can be directly replaced at the superconducting chip test insertion interface 101 through the superconducting chip interconnection module 102, thereby realizing the online replacement function of the superconducting chip.

[0036] In addition to the above examples, in other examples, the liquid holding chamber 105 is connected to an exhaust line 107, which is equipped with an exhaust valve and a pressure sensor. The exhaust line 107 ensures the safety of the pressure within the liquid helium test chamber 1. When the pressure within the liquid helium test chamber 1 is too high, the exhaust valve can be opened to release the pressure through the exhaust line 107. The pressure sensor can detect the pressure and ensure that the pressure within the liquid helium test chamber 1 is normal. In other examples, the liquid holding chamber 105 is further connected to an infusion line 108 for adding liquid helium to the liquid holding chamber 105 from the outside. A liquid helium electronic level gauge 109 is provided within the liquid holding chamber 105. In addition to providing helium from the helium tank 6 to the system to liquefy and form liquid helium, liquid helium can also be directly filled into the liquid helium test chamber 1 through the infusion pipeline 108. The liquid helium level in the liquid helium test chamber 1 is monitored by the liquid helium electronic level gauge 109 to ensure that the low-temperature magnetic shielding cover 801 can be immersed, providing an extremely low-magnetic liquid helium immersion test environment.

[0037] The above-mentioned various embodiments of the present invention can be used in combination. In some specific examples, a helium pressure reducing valve 601 and a flow controller 602 are provided on the pipeline connecting the helium tank 6 to the cold head 202 of the refrigerator. When performing superconducting chip testing, the system first performs a vacuum process through an external vacuum pump, maintains a high vacuum through a static sealing structure, and at the same time fills the system liquid helium test chamber 1 with high-purity helium at a certain pressure. Subsequently, the pulse tube refrigerator 2 is turned on. At this time, the helium can be liquefied by opening the high-purity helium tank 6 and the flow controller 602, or the liquid helium infusion operation can be directly performed through the infusion pipeline 108. When the liquid helium infusion volume reaches the requirement of the liquid helium electronic level gauge 109, the exhaust valve of the infusion pipeline 108 is closed and the refrigerator is allowed to reach temperature. After the refrigerator reaches temperature, the superconducting chip test insertion interface 101 is opened, and the superconducting chip 104 connected to the superconducting chip interconnection module 102 is inserted from the superconducting chip test insertion interface 101, and the system test is started. During the test, if the superconducting chip 104 needs to be replaced, the superconducting chip test insertion interface 101 can be opened again to replace the chip.

[0038] A multi-stage pre-cooling heat exchanger 7 is designed on the two-stage cold head and the outer wall of the cylinder of the pulse tube refrigerator 2. It can pre-cool the helium gas at room temperature step by step, and finally liquefy it in the condensing heat exchanger 3 connected to the second-stage cold head. The liquefied liquid helium can enter the liquid helium test chamber 1 through the liquid helium return line 5, thus achieving the helium liquefaction function. The helium evaporated in the liquid helium test chamber 1 reaches the condensing heat exchanger 3 through the cold helium return line 4. After recondensation, it flows back into the liquid helium test chamber 1 through the liquid helium return line 5, thus achieving zero evaporation of liquid helium during superconducting chip testing. In addition, the system is designed with a combined magnetic shielding structure of a low-temperature magnetic shield 801 and a room-temperature magnetic shield 802. This structure can ensure that the interior of the liquid helium test chamber 1 is in an extremely low magnetic field environment. The chip testing low-temperature system for helium liquefaction and recondensation in this example has a compact structure. The pulse tube refrigerator 2 is used to realize the liquid helium closed circulation function, ensuring that no liquid helium is consumed during the chip testing process, effectively reducing the cost of use. In addition, room temperature helium can be used for liquefaction, thereby ensuring that the system can be filled with liquid helium without external means. In addition, the system's efficient magnetic shielding structure eliminates the electromagnetic interference problems caused by the refrigerator and the external environment. The system has the advantages of compact structure, zero evaporation of liquid helium, low electromagnetic interference, and easy use.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A chip testing cryogenic system for helium liquefaction and recondensation, characterized in that: include: A liquid helium test chamber (1) is used to contain liquid helium to provide an immersion test environment; A pulse tube refrigerator (2) comprises a refrigerator compressor (201), a refrigerator cold head (202) and a refrigerator cold shield (203), wherein the refrigerator cold head (202) is connected to a condensing heat exchanger (3), the liquid helium test chamber (1) and the condensing heat exchanger (3) are located in the refrigerator cold shield (203), the refrigerator cold head (202) is connected to the liquid helium test chamber (1) via a cold helium gas return line (4), and the condensing heat exchanger (3) is connected to the liquid helium test chamber (1) via a liquid helium return line (5); A helium tank (6) is connected to the refrigerator cold head (202) via a pipeline.

2. The chip testing cryogenic system for helium liquefaction and recondensation according to claim 1, characterized in that: A pre-cooling heat exchanger (7) is wound around the outside of the refrigerator cold head (202).

3. The chip testing cryogenic system for helium liquefaction and recondensation according to claim 1, characterized in that: The helium liquefaction and recondensation chip testing low-temperature system further comprises a magnetic shielding device (8), and the magnetic shielding device (8) is used to form a low magnetic field environment inside the liquid helium testing chamber (1).

4. The chip testing cryogenic system for helium liquefaction and recondensation according to claim 3, characterized in that: The magnetic shielding device (8) comprises a low-temperature magnetic shielding cover (801) and a normal-temperature magnetic shielding cover (802), wherein the low-temperature magnetic shielding cover (801) is located in the liquid helium test chamber (1), and the normal-temperature magnetic shielding cover (802) is covered outside the refrigerator cold screen (203).

5. The chip testing cryogenic system for helium liquefaction and recondensation according to any one of claims 1 to 4, characterized in that: The liquid helium test chamber (1) is provided with a superconducting chip test insertion interface (101) for plugging in a superconducting chip interconnection module (102); the superconducting chip interconnection module (102) is provided with a long strip connector (103); the long strip connector (103) is used to connect a superconducting chip (104) so ​​as to extend into the liquid helium test chamber (1) for testing the superconducting chip.

6. The chip testing cryogenic system for helium liquefaction and recondensation according to claim 5, characterized in that: The liquid helium test chamber (1) comprises a liquid holding chamber (105) and a plug-in chamber (106) connected to the liquid holding chamber (105); the liquid holding chamber (105) holds liquid helium; the superconducting chip test insertion interface (101) is provided at the end of the plug-in chamber (106); and a reverse check device is provided at the superconducting chip test insertion interface (101) to prevent gaseous helium from flowing out of the superconducting chip test insertion interface (101).

7. The chip testing cryogenic system for helium liquefaction and recondensation according to claim 6, characterized in that: The liquid holding cavity (105) is connected to an exhaust pipeline (107), and an exhaust valve and a pressure sensor are provided on the exhaust pipeline (107).

8. The chip testing cryogenic system for helium liquefaction and recondensation according to claim 7, characterized in that: The liquid holding cavity (105) is also connected to a liquid infusion pipeline (108) for adding liquid helium into the liquid holding cavity (105) from the outside.

9. The chip testing cryogenic system for helium liquefaction and recondensation according to claim 8, characterized in that: A liquid helium electronic level gauge (109) is provided inside the liquid holding cavity (105).

10. The chip testing cryogenic system for helium liquefaction and recondensation according to any one of claims 1 to 4, characterized in that: A helium pressure reducing valve (601) and a flow controller (602) are provided on the pipeline connecting the helium tank (6) to the refrigerator cold head (202).

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