WO2024032484A1

WO2024032484A1 - Test structure for superconducting quantum chip and test method for superconducting quantum chip

Info

Publication number: WO2024032484A1
Application number: PCT/CN2023/111170
Authority: WO
Inventors: 赵勇杰; 王小川; 李业; 李松
Original assignee: 本源量子计算科技（合肥）股份有限公司
Priority date: 2022-08-09
Filing date: 2023-08-04
Publication date: 2024-02-15

Abstract

A test structure for a superconducting quantum chip and a test method for a superconducting quantum chip. The test structure comprises: a reference resonant element (201), which has a first designed resonant frequency; a tested resonant element (202, 202a), which is provided with a first element (103) and a second element (104) that are configured to be connected by means of a first interconnection structure (102) and to be located on different planes, wherein the tested resonant element (202, 202a) is configured on the basis of design parameters, and the design parameters are preset according to the first designed resonant frequency; and a first electrical element (203), which is independently coupled to the reference resonant element (201) and the first element (103) of the tested resonant element (202, 202a), respectively. In the present application, a reference resonant element (201) is introduced into a test structure as the contrast of a tested resonant element (202, 202a), the reference resonant element (201) is also coupled to a first electrical element (203), and has a preset relationship with the tested resonant element (202, 202a) in terms of a resonant frequency; therefore, the relationship between measurement results of the reference resonant element (201) and the tested resonant element (202, 202a) can effectively reflect the on-off performance or connectivity of the tested resonant element (202, 202a).

Description

Test structure of superconducting quantum chip and test method of superconducting quantum chip

This application requests the priority of a Chinese patent application submitted to the China Patent Office on August 9, 2022, with the application number 202210946893.3 and the application title "A test method, test structure, and application". It requests priority on August 9, 2022. The priority of the Chinese patent application submitted to the China Patent Office with the application number 202210946901.4 and the application title "An interconnect performance testing component" is requested to be submitted to the China Patent Office on August 9, 2022 with the application number 202210948131.7. The priority of the Chinese patent application entitled "An Air Bridge Test Assembly", the entire contents of these patents are incorporated into this application by reference.

Technical field

The present application relates to the field of quantum chips, and more specifically to a test structure of a superconducting quantum chip and a test method of a superconducting quantum chip.

Background technique

Interconnection technology plays an important role in the development of superconducting quantum chips, in which interconnection structure is the key to interconnection technology. When an interconnection structure is applied to a superconducting quantum chip, it is usually necessary to consider whether the interconnection of the interconnection structure meets the needs of transmitting radio frequency signals. Therefore, there is an urgent need for a solution that can characterize the performance of interconnect structures in superconducting quantum chips for transmitting radio frequency signals, such as continuity or connectivity.

Contents of the invention

This application provides a test structure for a superconducting quantum chip and a test method for a superconducting quantum chip, which can be applied to evaluate the continuity or connectivity and other properties of various interconnect structures.

In a first aspect, the present application provides a test structure. The test structure includes: a reference resonant element having a first designed resonant frequency; and a resonant element under test having a third out-of-plane resonant element configured to be connected through a first interconnection structure. One component and a second component, the measured resonant component is configured based on design parameters, and the design parameters are preset and generated based on the first design resonant frequency; the first electrical component is independently connected to the first component. The reference resonant element is coupled to the first element of the measured resonant element.

In a second aspect, the present application provides a test structure for determining the connectivity of a through silicon via interconnection structure. The test structure includes: a read bus extending along a first preset direction; at least one interconnect unit, And each interconnection unit includes n interconnection structures, n is an integer greater than or equal to 1; and at least one resonator arranged side by side and spaced along the first preset direction, the at least one resonator is connected to the at least one resonator. At least one resonator corresponding to one interconnection unit; each resonator is manufactured according to the designed resonant frequency parameters, and each resonator moves from the first end to the second end along a second direction different from the first preset direction. The preset direction extends; each resonator is interrupted by the interconnection structure in the corresponding interconnection unit to form m sub-elements, and m=n+1; wherein the m sub-elements are connected through the interconnections in the interconnection unit The structures are connected in turn and the resonator is coupled to the read bus via a sub-element located at the first end.

In a third aspect, the present application provides a testing method for determining the connectivity of a through-silicon via interconnection structure. The testing method includes: obtaining a test structure, the test structure having a first electrical component, a reference resonant component and a A resonant element under test, the first electrical element coupled to the reference resonant element; wherein the resonant element under test is made based on a reference resonant element interrupted by an interconnection structure, and the resonant element under test has an interconnection The proximal element and the distal element are structurally connected and in different planes, and the measured resonant element is coupled to the first electrical element through the proximal element; The measured resonant element transmits a microwave detection signal; the feedback signal obtained from the first electrical element is used to calculate the reference resonant frequency of the reference resonant element and the measured resonant frequency of the measured resonant element to form a resonant frequency result set. ; Confirming the connectivity of the interconnection structure according to a preset pattern based on the set of resonant frequency results.

This application introduces a reference resonant element into the test structure as a comparison of the resonant element under test. The reference resonant element is also coupled to the first electrical element and has a preset relationship between the resonant frequencies with the resonant element under test. Therefore, the measurement results of the two The relationship between them can effectively reflect the continuity or connectivity of the resonant component under test.

Description of drawings

Figure 1 is a schematic structural diagram in the top view direction of the test structure provided in Embodiment 1 of the present application.

Figure 2 is a partial cross-sectional structural diagram in the isometric direction of the test structure provided in Embodiment 1 of the present application.

FIG. 3 is a schematic structural diagram in a top view of another test structure provided in Embodiment 1 of the present application.

Figure 4 is a schematic structural diagram in the top view direction of two other test structures provided in Embodiment 1 of the present application.

Figure 5 is a schematic diagram of the steps of the testing method provided in Embodiment 1 of the present application.

FIG. 6 is a schematic layout diagram of the first test structure provided in Embodiment 2 of the present application.

FIG. 7A is a partial cross-sectional structural schematic diagram of the first test structure provided in Embodiment 2 of the present application.

FIG. 7B is a partial cross-sectional structural schematic diagram of the second test structure provided in Embodiment 2 of the present application.

FIG. 8 is a schematic diagram of the layout structure of the third test structure provided in Embodiment 2 of the present application.

FIG. 9 is a schematic diagram of the layout structure of the fourth and fifth test structures provided in Embodiment 2 of the present application.

FIG. 10 is a schematic diagram of the layout structure of the sixth test structure provided in Embodiment 2 of the present application.

FIG. 11 is a schematic diagram of the layout structure of the seventh test structure provided in Embodiment 2 of the present application.

Figure 12 is a schematic structural diagram of two coplanar waveguides crossing vertically and horizontally and connected by an air bridge.

Figure 13 is a schematic structural diagram of the first test structure provided in Embodiment 3 of the present application.

Figure 14 is a partially enlarged structural schematic diagram of part A of the second resonant cavity in the first test structure.

Figure 15 is a schematic structural diagram of the second test structure provided in Embodiment 3 of the present application.

Figure 16 is a schematic structural diagram of the third test structure provided in Embodiment 3 of the present application.

Figure 17 is a schematic structural diagram of the first air bridge in the test structure provided in Embodiment 3 of the present application.

Figure 18 is a schematic structural diagram of the second air bridge in the test structure provided in Embodiment 3 of the present application.

Figure 19 is a schematic structural diagram of the third air bridge in the test structure provided in Embodiment 3 of the present application.

Reference signs:
101-substrate; 102-interconnection structure; 103-first component; 104-second component; 201-reference resonant component; 202-resonant component under test;
202a-the resonant component under test; 203-the first circuit component; 204-the second circuit component;
301-first microwave transmission line; 302-continuous resonant cavity; 303-segmented resonant cavity; 303a-segmented resonant cavity; 3031-first element; 3031a-
First component; 3032-second component; 3032a-second component; 3033-interconnect; 3034-barrier layer; 3035-support pillar; 401-first chip; 402-second chip; 502-second microwave transmission line ;
601-first coplanar waveguide; 602-second coplanar waveguide; 6021-first sub-section; 6022-second sub-section; 603-air bridge; 70-first microwave signal line; 71-first resonant cavity; 72-second resonant cavity; 73-air bridge; 74-interruption area; 80-second microwave signal line; 731-first end; 732-second end; 733-transition portion; 733a-transition portion; 733b -Transition part; 801-substrate; 901-first section; 902-second section; 903-third section.

Detailed ways

The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.

With the development of superconducting quantum chips, the layout of various circuits and components on superconducting quantum chips has become increasingly difficult. Even in some cases, these lines and components have to cross each other, which may cause signal interference such as crosstalk. The fragility of quantum systems and their tendency to be easily affected by noise coupled into the system means that the impact caused by the intersection of circuits and components cannot be ignored.

Therefore, people began to seek higher-integration preparation methods or structures. Various interconnection technologies can integrate more bits and components within an acceptable plane size, so they have received widespread attention. Common interconnection technologies include through silicon via (TSV) interconnection technology, flip-chip interconnection technology, and air bridge interconnection technology.

Through-silicon via interconnection technology refers to a technology that realizes interconnection between different chips or between different surfaces of chips by making through holes in the Z-axis direction on silicon wafers and filling the inside of the through holes with conductive substances. Through silicon via interconnection technology can realize three-dimensional interconnection and integration between chips. It has shorter signal lines and smaller signal delay and crosstalk, and can show higher packaging efficiency under the same plane size. Therefore, as a very promising chip interconnection technology, the industry generally expects to introduce it into the manufacturing process of quantum chips—for example, the superconducting quantum chips focused on in this article.

Flip-chip interconnection technology, also known as flip-chip welding technology, can effectively improve the integration of chips and prevent the chip plane size from increasing too quickly. Therefore, in view of the increasing requirements for the number of qubits, flip-chip interconnection technology has been selected and used in the production of superconducting quantum chips and has high hopes. Currently, superconducting quantum chips based on flip-chip interconnections usually use indium to make interconnects between chips. Typically, these interconnects also serve as transmission channels for signals to be routed between chips.

Air bridge interconnection technology uses air bridges as transitional connection structures at the intersections of lines and components. The air bridge can transition and change the planar wiring structure to a three-dimensional direction, so that structures that cross each other in the plane can "go around" each other through the air bridge. Therefore, some lines and components can be constructed as separate multi-segment structures based on air bridges. These separated structures can be bridged through air bridges to avoid the influence of crosstalk signals, thereby achieving high signal transmission quality.

In interconnection technology, the interconnection structure plays a key role. For example, through silicon vias in through silicon via interconnection technology, indium pillars in flip chip interconnection technology, and air bridges in air bridge interconnection technology. Since the operation and measurement of superconducting quantum chips require radio frequency signals, when an interconnect structure is applied to a superconducting quantum chip, it is usually necessary to consider whether the interconnections of the interconnect structure meet the needs of transmitting radio frequency signals. Based on chip quality considerations, the quality of the interconnect structure needs to be carefully inspected. Therefore, there is an urgent need for a solution that can characterize the performance of interconnect structures in superconducting quantum chips for transmitting radio frequency signals, such as continuity or connectivity.

Embodiment 1: Test the continuity or connectivity of the through silicon via interconnection structure.

As mentioned earlier, superconducting quantum chips often require the participation of radio frequency signals in order to manipulate and read them. Therefore, stable transmission of radio frequency signals is very important. On the other hand, in order to improve integration, through-silicon via interconnect technology can be used in superconducting quantum chips for three-dimensional layout and packaging of various circuits and components. Therefore, when these lines or components in a three-dimensional layout need to be associated with radio frequency signals, it is necessary to ensure that the interconnection structure of the through silicon via has good connectivity (such as on-off, quality in the case of connectivity, etc.). However, how to confirm this is a difficulty.

At present, the continuity of interconnection structures is mainly judged by detecting and characterizing the DC characteristics of the interconnection structure. For example, by measuring resistance—a connected interconnect indicates an open circuit, and a short interconnect indicates a good connection. However, this does not, or does not always, effectively equate to the performance of the interconnect structure for RF signals. Other attempts have relied on measurements of insertion loss, reflection, etc. to characterize RF performance. However, some current superconducting quantum chips need to be dropped to extremely low temperatures such as 10mK level to function properly. At such a temperature, the front and rear stages of the chip will be connected to various radio frequency devices, and the TiN attached to the TSV interconnect structure will enter the superconducting state, so its insertion loss and reflection are extremely small, making characterization difficult.

In view of this, different from the above attempts, in the example of this application, the inventor proposes a test structure and a test method that can be implemented through the test structure. It can be used to judge the connectivity of through-silicon via interconnect structures, thereby improving the production quality of superconducting quantum chips, shortening their production cycle, and improving production efficiency. It can be understood that based on the solution of the example of this application, in some other fields or other types of quantum chips, it can also be applied to scenarios that require connectivity of through-silicon via interconnect structures related to radio frequency signal performance.

Generally speaking, the solution illustrated in this application mainly measures the resonant frequency and judges the connectivity of the through-silicon via interconnection structure based on the measurement results. Therefore, the reference device and the device under test are configured as a whole. The device under test is configured with an interconnection structure, and the corresponding reference device is not configured with an interconnection structure. Moreover, the reference device and the device under test have the same, or close to, or expected deviation in the designed resonant frequency, for example, the phase difference frequency is 50 MHz.

Therefore, reference devices and devices under test are made based on the resonant frequencies of these designs. So in theory, when the manufacturing process is good (including good connectivity of the interconnect structure), the actual resonant frequencies of the reference device and the device under test will be related according to the aforementioned design method—for example, the same or close or expected deviation.

When problems arise in the manufacturing process of the interconnect structure, the quality of the interconnect structure deteriorates, and therefore its connectivity also deteriorates. At the same time, since the reference device is not configured with an interconnection structure, the aforementioned manufacturing process problems will not affect the reference device. The resonant frequency of the device under test will then be identifiably different from the resonant frequency of the reference device. By identifying this difference, you can determine that the interconnect structure has developed a quality problem, that is, it has poor connectivity.

Based on this understanding, the inventor proposed in an example such a test method that can be implemented to determine the test structure of the connectivity of the through silicon via interconnection structure.

See Figure 1 and Figure 2. The test structure includes a first circuit element 203 (or first electrical element), and a reference resonant element 201 and a measured resonant element 202 respectively coupled to the first circuit element 203.

1 is a schematic top view of the test structure configured on the substrate 101 in the example of the present application; for convenience of description and display, the first element 103 and the second element 104 included in the resonant element 202 under test are respectively It is expressed in a visible way, but it can be seen from FIG. 2 that the first element 103 and the second element 104 are respectively located on the two surfaces (front and back) of the substrate 101; that is, each element is selectively located on the front of a chip. Or the back. Therefore, in the front plan view direction shown in FIG. 1 , in the actual device, the first component 103 is visible from the front, while the second component 104 is not visible from the back.

2 is a schematic partial cross-sectional structural diagram of FIG. 1 , which mainly discloses the distribution of the interconnection structure 102 (i.e., the first interconnection structure) in the substrate 101 and its two ends respectively connected with the first element 103 and the first element 103 . The cooperative relationship between the two components 104. In the field of superconducting quantum chips, the interconnect structure 102 is usually made of superconducting material, and is produced by making holes (such as etching) on the substrate, and then plating a layer of superconducting material film on the inner wall. In the structure shown in Figure 2, interconnect structure 102 is represented as a generally hollow cylindrical structure. In other examples, it can be constructed as a solid cylinder if the process is feasible. According to Figures 1 and 2, it can be seen that the first circuit element 203 is coplanar with the reference resonant element 201; while the first element 103 of the measured resonant element 202 is coplanar with the first electrical element, and the second element 104 is coplanar with it. Different side. In FIG. 2 , the first component and the second component are respectively configured with holes corresponding to the interconnection structure 102 ; the sizes of the holes and the relative sizes of the two components shown therein are only schematic representations and do not constitute specific limitations.

The reference resonant element 201 has a first design resonant frequency; the measured resonant element 202 has a second design resonant frequency; the design resonant frequency can be obtained through simulation calculations using electromagnetic simulation software, so that corresponding structural design parameters can also be obtained. Under ideal conditions, when these two resonant elements are prepared as expected and with high quality, the measured value of the resonant frequency of the reference resonant element 201 is usually close to, or even equal to, the first design resonant frequency; similarly, The measured value of the resonant frequency of the resonant element 202 is usually close to, or even equal to, the second designed resonant frequency. Moreover, through appropriate design, the first design resonant frequency and the second design resonant frequency can be made equal, or the difference between the two can be within a given range.

During the implementation of the test method, the first circuit element 203 can receive the detection signal and pass it through the two aforementioned couplings. The response result of the resonant element determines the measured value of the resonant frequency of the reference resonant element 201 (first measured value) and the measured value of the resonant frequency of the measured resonant element 202 (second measured value) through existing methods such as signal processing and calculation. . Such a measurement method can be implemented, for example, based on the matching coupling structure between the read bus and the read resonant cavity in the superconducting quantum chip. Therefore, the first circuit element 203 may be the read bus, and the reference resonant element 201 and the resonant element under test 202 may be their corresponding read resonant cavities.

As a solution to verify the through silicon via interconnection structure 102 , the resonant element 202 under test is configured with the interconnection structure 102 . That is, if the reference resonant element 201 is a continuously arranged resonant cavity structure, such as a coplanar waveguide; then the measured resonant element 202 can correspond to a coplanar waveguide interrupted by the through silicon via interconnection structure 102 .

Therefore, the resonant element 202 under test may have a first element 103 and a second element 104; with the interconnection structure 102 as the dividing point, the side adjacent to the first electrical element is the first element 103, and the side far away from the first electrical element is the first element 103. On one side is the second element 104 . Here, a resonant element under test is configured with an interconnection structure as an example. It can be known that when a resonant element under test is configured with at least two interconnection structures, then the resonant element under test can have at least three elements; for example The first element, the second element, the third element, the fourth element, etc., and so on.

Considering the existence of the through silicon via interconnection structure 102, the first element 103 and the second element 104 are distributed in different planes. Therefore, in some examples, the test structure is configured to the substrate 101 , and as mentioned above, the first electrical component may be located on the front side of the substrate 101 , the reference resonant element 201 is located on the front side of the substrate 101 , and the measured resonant element 202 is located on the front side of the substrate 101 . One element 103 is located on the front side of the substrate 101, the second element 104 of the resonant element under test 202 is located on the back side of the substrate 101, and the interconnection structure 102 located in the substrate 101 extends from the front side of the substrate 101 to the back side of the substrate 101 and Both ends are connected to the first component 103 and the second component 104 respectively.

In view of the manufacturing process, materials, etc., there may be differences between the designed resonant frequency of the resonant element and the measured resonant frequency measured after the resonant element is actually manufactured. The measured resonant element 202 configured in the example of this application is based on The reference resonant element 201 is designed and manufactured. That is, the resonant element 202 under test is made based on design parameters, and the design parameters are preset and generated based on the first design resonant frequency of the reference resonant element 201 . The design parameters include, for example, the materials selected in the manufacturing process, environmental and process conditions, structural parameters, etc. Based on this, the measured values of the resonant frequencies of the resonant element under test 202 and the reference resonant element 201 that are produced with high quality are close to or the same or meet expected deviations.

In the example of this application, the number of measured resonant elements 202 can be chosen freely. When there are multiple resonant elements 202 to be measured, these resonant elements 202 to be measured can adopt the same structural design, thereby avoiding the deviation in the measurement results caused by the presence of a single or a small number of resonant elements 202 to be measured in some cases. Problems with low accuracy or unrepeatable results. Further, the number of interconnection structures and the positions of the interconnection structures (which can be measured by the distance from the first circuit element 203) in different resonant components under test 202 can also be selected as needed, for example, they are all the same. Or completely different, or partially the same, partially different, etc.

In order to study the impact of configuring the interconnection structure 102 at different positions in the resonant element 202 under test, the resonant element 202 under test can be classified into multiple groups according to the different positions of the interconnection structure 102, and each group contains at least one under test. Resonant elements 202, and the positions of the interconnect structures 102 of the resonant elements 202 under test in the same group are the same. In some such examples, the first element 103 of each resonant element under test 202 has a first parameter and the second element 104 has a second parameter. Based on this, the first parameter and the second parameter jointly determine the resonant frequency of the measured resonant element 202 . The first parameter and the second parameter are, for example, its length, so they together constitute the length of the resonant element 202 under test. For different groups or different types of resonant elements 202 under test, their first parameters may be configured differently.

For example, in the test structure shown in FIG. 3 , there are two types of resonant elements 202 under test (each type includes one, two types in total), and the interconnection structure 102 of one of the resonant elements under test 202 is close to the first circuit element. 203, while the interconnection structure 102 of the other resonant element 202a under test is far away from the first circuit element 203. Moreover, the length of the first element 103 of the measured resonant element 202 is shorter than the length of the first element 103 of the measured resonant element 202a. Correspondingly, the length of the second element 104 of the measured resonant element 202 is greater than the length of the second element 104 of the measured resonant element 202a. 104 length.

Furthermore, based on some measurement needs, the second circuit element 204 may also be configured in some examples. Similar to the first circuit element 203, it is also independently coupled to the second element 104 of the reference resonant element 201 and the resonant element under test 202. Therefore, the two ends of the reference resonant element 201 are coupled to the first circuit element 203 and the second circuit element 204 respectively; and the two ends of the measured resonant element 202 (not labeled in FIG. 4 ) are also coupled to the first and second circuit elements respectively. 204 coupling. The second circuit element 204 can have the same structure as the first electrical element, and functionally it can also be used to measure the resonant frequencies of the reference resonant element 201 and the measured resonant element 202 to obtain corresponding measurement values. For example, see Figure A in Figure 4.

Furthermore, on the basis of Figure A, more than one interconnection structure 102 can be configured on the resonant element 202 under test. For example, in Figure B in Figure 4, each resonant element 202 under test is configured with two interconnection structures. Connect structure 102. And, therefore, the resonant element under test 202 includes a first section element, a second section element and a third section element which are sequentially connected (series connected) through the two interconnection structures 102 . Three segment components. The first segment of components is coupled with the first electrical component, and the third segment of components is coupled with the second circuit component 204 . It should be noted that the interconnection structure 102 is a structure that penetrates the substrate 101 and extends to both surfaces of the substrate 101 . Therefore, the aforementioned first section of components and the third section of components can be coplanar (also coplanar with the first circuit component 203 and the second circuit component 204), and are respectively out of plane with the second section of components (also respectively coplanar with the second section of components). The first circuit element 203 and the second circuit element 204 are on opposite sides).

According to the structure shown in Figure A in Figure 4, based on the configuration of an interconnection structure 102 and its position of the resonant element 202 under test, an additional interconnection structure 102 is configured as shown in Figure B in Figure 4 to the longer one of the first element 103 and the second element 104, so that the first section element and the second section element can be produced by interrupting the original first element 103 by adding an interconnection structure 102 . Then, at this time, the corresponding third segment element is the original second element 104. Similarly, the first segment of components is the original first component 103, while the second segment of components and the third segment of components are generated by the original second segment of components 104 being interrupted by a newly added interconnection structure 102.

As mentioned above, based on the application example of the superconducting quantum chip, the test structure can be configured as a read bus and at least one read resonator coupled to each other. Wherein, the read bus line extends generally in the first direction/horizontal direction, each read resonator generally extends along the second direction/vertical direction, and all the read resonators may be arranged at intervals along the horizontal direction, As shown in Figure 4.

Correspondingly, each read resonator is configured with one interconnection unit, and each interconnection unit has a positive integer number (n) of interconnection structures 102 . In other words, in such an example, each read resonator is interrupted by the interconnect structure 102 in its corresponding interconnect unit to form one (m) more than the number of the corresponding interconnect structures 102, and m=n +1). In this example, by reading the theoretical resonant frequency and the actual resonant frequency measurement value of the resonator, you can also try to determine whether the interconnection structure of the resonator is connected or disconnected.

Due to the stability of the fabrication process and the deviation between the theoretical design and the actual process, it would be beneficial to configure a resonator without the interconnection structure 102 as the reference resonator/reference resonant element 201, as described above. The reference resonator may have substantially the same structure and arrangement as the resonator having the interconnect structure 102 . In addition, the test structure can also optionally be configured with two reading buses. Correspondingly, the two reading buses can be respectively coupled to the sub-element located at the first end and the sub-element located at the second end of the resonator. Both can measure the resonant frequency independently from both ends of the resonator.

In the above structure, for the measurement of the resonant frequency, those skilled in the art can use the technical means of microwave resonators in related fields to perform the measurement. To avoid redundancy, it can be briefly described as: λ = v/f; Among them, v is the wave speed, f is the frequency, μ is the magnetic permeability, and ε is the dielectric constant. Then the frequency is calculated as Therefore, after the substrate is determined, μ and ε are constants, and it can be calculated to know that the frequency f of the resonator is related to the length of the resonator. So for the measurement structure in Figure 1, if the interconnection structure 102 is disconnected, only the resonant frequency of the reference resonant element 201 can be measured, and the resonant frequency of the measured resonant element 202, due to the resonant cavity (first element 103) The length is too short to measure the effective value, and the second element 104 is disconnected from the interconnection structure, so it is not coupled to the first circuit element 203 and its resonant frequency cannot be measured. That is, a resonant frequency can be measured, which belongs to the reference resonant component. If the interconnection structure 102 is not disconnected/fully connected, the resonant frequencies of the reference resonant element 201 and the measured resonant element 202 can be measured, that is, two resonant frequencies can be measured.

Similarly, in the test structure shown in Figure 3, if the interconnection structure 102 is all disconnected, only the resonant frequencies of the reference resonant element 201 and the resonant element under test 202a (mainly contributed by its first element 103, can be measured, And its second component 104 cannot be measured because the interconnection structure 102 is disconnected), that is, two resonant frequencies. As for the resonant frequency of the measured resonant element 202, the effective value cannot be measured because the length of the resonant cavity (first element 103) is too short. If the interconnection structure 102 is not disconnected/fully connected, the resonant frequencies of the reference resonant element 201 and the two measured resonant elements 202 can be measured, that is, three resonant frequencies can be measured.

In conjunction with the above test structure, a test method for determining the connectivity of the through silicon via interconnect structure 102 can be implemented. Moreover, this connectivity can be used to verify the design process and parameters of the through-silicon via interconnection structure 102 of the chip in order to obtain better manufacturing processes and design parameters of the through-silicon via interconnection structure 102, thereby obtaining high-quality Through silicon via interconnect structure 102 .

Furthermore, according to the described test structure, the connectivity of the through silicon via interconnect structure 102 determined by this test method can also well reflect its performance in transmitting radio frequency signals. Therefore, in the superconducting quantum chip There is huge potential and value in the production.

Overall, as shown in Figure 5, the testing method mainly includes the following steps:

S101. Obtain the test structure.

The test structure can be produced with reference to the content disclosed above. Generally, the test structure may include a first electrical component, a reference electrical component and an electrical component to be tested. The electrical component to be tested is made based on the reference electrical component interrupted by the interconnection structure 102 . In other words, except for the interconnection structure 102 , the electrical component under test may have the same or similar design structure parameters, materials, and process manufacturing conditions as the reference electrical component.

The electrical components to be tested can be produced in the following ways:

A section of corresponding material is made on the upper and lower surfaces of the substrate/substrate 101 - which can be described as a proximal element distributed in different surfaces. and distal elements—and. The proximal element is close to the first electrical element, and the distal element is far away from the first electrical element. Holes are made along the thickness of the substrate, and corresponding materials (such as conductor materials, etc.) are filled in the holes. Both ends of the holes are electrically contacted and connected to the aforementioned section of corresponding materials. In integrated circuit-related processes, the fabrication of the through-silicon via interconnection structure 102 generally includes operations such as through-hole fabrication, through-hole insulation, barrier layer, seed layer, and filling plating.

Thereby, the first electrical component is coupled with the reference electrical component, and the electrical component to be measured is coupled with the first electrical component through the aforementioned proximal component.

S102. Use microwave detection signals to measure the resonant frequency.

Depending on the construction of the test structure, the microwave detection signal may be transmitted through the first electrical component to the reference electrical component and the electrical component to be tested. Wherein, the first electrical component may be selected as a transmission line such as a coplanar waveguide, which can be used to transmit microwave signals. In a superconducting quantum chip, it can be described as a readout line (such as Readout Line). The reference electrical component and the electrical component to be measured can be resonant cavity components (such as Readout Resonator) coupled with the first electrical component, and can also be made of coplanar waveguides. Generally, the quality factor is calculated by the ratio of the resonant frequency and the bandwidth. For example, corresponding to the example of a superconducting quantum chip, using the first electrical component to measure the resonant frequency of the resonant component may be to obtain the corresponding data by using a vector network analyzer for testing, and then obtain the corresponding Q value through data fitting; as Avoid going into detail.

S103. Obtain data from the feedback signal, and confirm the connectivity of the interconnection structure 102 accordingly.

Due to the coupling relationship between the first electrical component and the reference electrical component and the electrical component to be measured respectively, the microwave signal input through the first electrical component can act on the two reference electrical components and the electrical component to be measured, and then the signal can be fed back to the first electrical component. Electrical components are measured using microwave and electrical equipment in the field, and the reference resonant frequency of the reference electrical component and the measured resonant frequency of the electrical component to be measured are calculated, that is, the measured values of the resonant frequencies of the two components, and thereby A set of resonant frequency results can be formed. Further, the connectivity of the interconnection structure 102 can be confirmed according to the preset pattern according to the resonant frequency result set.

Because the resonant frequency combination set includes the measured value of the resonant frequency of the reference electrical component and the measured value of the resonant frequency of the electrical component under test. Therefore, the connectivity of the interconnect structure 102 can be confirmed based on different utilizations of these measured values—preset modes.

For example, since the reference electrical component is not fabricated through the through-silicon via interconnect structure 102, the resonant frequency can always be measured theoretically. Since the electrical component under test involves the production of the through-silicon via interconnection structure 102, the quality of the interconnection structure 102 will affect whether its corresponding resonant frequency can be measured. When the connectivity of each interconnection structure 102 is good, the number of measured components and measured resonant frequencies should be the same. Then, when the number of measured resonant frequencies in the resonant frequency result set is used as a basis, when the number of measured resonant frequencies in the resonant frequency result set is the same as the number of electrical components to be tested, it is determined that the interconnection structure 102 has good connectivity. On the contrary, if the numbers are different, it may be determined that one or more interconnect structures 102 have poor connectivity.

Further, as described above, the size of the resonant frequency is related to the length of the resonator. Moreover, when the resonant element is fabricated through the through-silicon via interconnection structure 102 and coupled to the first electrical element, if the interconnection structure 102 has poor connectivity, theoretically the corresponding measured part is the part immediately adjacent to the first electrical element (such as the aforementioned close proximity). The resonant frequency of the terminal element, such as the first element 103 in Figure 1). Therefore, when the length of the proximal element is short, the measured resonant frequency will be very high and may be considered to be unmeasured in practical applications.

Furthermore, when the length of the portion of the measured resonant element 202 close to the first electrical element (proximal element) is relatively longer, and the length of the portion far away from the first electrical element (distal element, such as the second element 104 in FIG. 1 ) is shorter, the resonant frequency of the proximal component in the interconnection structure 102 can be measured when the interconnection structure 102 has poor connectivity—but its measured value is the same as the measured electrical value when the interconnection structure 102 has good connectivity. There will be clear and identifiable differences in the measured values of the component's resonant frequency. Therefore, based on this, the aforementioned preset mode may also include: confirming the connectivity of the interconnection structure 102 by comparing the reference resonant frequency and the measured resonant frequency in the resonant frequency result set. The reference resonant frequency can reflect the measured value of the resonant frequency of the electrical component under test when the interconnection structure 102 has good connectivity; this is because the electrical component under test is manufactured according to the design parameters determined by the design of the reference electrical component. . And it can be known that in this case, when the reference resonant frequency is equal to the measured resonant frequency or the difference is within a preset range, it can be determined that the connectivity of the interconnection structure 102 is good.

In addition, when the interconnect structure 102 and the resonant element fabricated based thereon, as well as the coupling structure with the first electrical element, are used in, for example, a superconducting quantum chip, an important performance index parameter that is of concern is, for example, the quality factor (Q value, Q factor, Quality Factor). The method for calculating the quality factor can adopt existing technology in the field, and this application does not specifically limit this. For example, through the frequency method, that is, calculating the Q value in the frequency domain, such as the frequency conversion method, etc.

Therefore, the above-mentioned connectivity of the through silicon via interconnection structure 102 may also include a quality factor for evaluating components based on this; and, the higher the quality factor, that is, the Q value, the better the connectivity of the interconnection structure 102 . Correspondingly in the result set via the resonant frequency After confirming that the connectivity of the interconnect structure 102 meets the requirements, the quality factor can be further measured. That is, in some examples, the testing method may also include: when the interconnection structure 102 has good connectivity, measuring the quality factors of the electrical component under test and the reference electrical component, and performing an optional comparison. Through comparison, the component with the best quality factor can be selected from the compared objects, so that the arrangement position and structural parameters of the interconnection structure 102 and the corresponding manufacturing process of the electrical component under test can be more ideal, and then the actual chip can be produced. When necessary, implement corresponding plans.

As a further optimization option, in some examples, the interconnection structure 102 can also be selected for structural adjustment in order to obtain better manufacturing conditions for the interconnection structure 102 actually used in some cases. For example, taking the interconnection structure 102 as a cylinder as an example, when it is determined that the interconnection structure 102 is connected by comparing the number of resonant frequencies in the resonant frequency result set or the comparison result, different cylindrical interconnection structures can be further targeted. 102 diameter and related quality factors are investigated.

Therefore, the testing method may also include: when it is determined that the interconnection structure 102 has good connectivity through the resonant frequency, and there are at least two corresponding electrical components to be tested, then the quality of the corresponding electrical components to be tested and the reference electrical component may be determined. factors are measured. Then, from these determined quality factors, the electrical component under test with the smallest absolute value of the difference between the quality factor and the quality factor of the reference electrical component is selected as the component with good radio frequency performance.

In the above example, the quality factor of the measured electrical component that meets the requirements is compared with the quality factor of the reference electrical component. In other examples, a ratio can be made between the quality factors of the electrical component under test that meet the requirements. In other words, when the connectivity of the corresponding interconnection structure 102 is confirmed to be good and there are at least two corresponding electrical components under test, the corresponding electrical components under test can be measured, and the electrical component under test with the largest quality factor can be measured. Components are judged to have good RF performance.

In short, in some examples of the present application, the test of the connectivity of the through silicon via interconnection structure 102 may include a judgment on whether it is connected, and further include a judgment on the quality of the connection if it is connected. Whether the connection is connected can be determined by quantitative comparison of the measured value of the measured resonant frequency and numerical comparison with the measured value of the reference resonant frequency. The connectivity quality is mainly determined by numerical comparison of the quality factors, and the numerical comparison can also include the comparison of the quality factors of the components corresponding to the measured resonant frequency and the reference resonant frequency, or the comparison of the quality factors corresponding to the measured resonant frequency. Quality factor comparison between components.

Example 2: Test the continuity or connectivity of the indium pillar.

When making superconducting quantum chips, flip-chip soldering technology can be used to integrate more bits and components within an acceptable plane size. Flip-chip soldering technology requires the use of interconnects, and in superconducting quantum chips, indium pillars are often chosen. That is, indium pillars are used to physically connect the upper and lower chips.

In order to further utilize the limited space of the chip, some of the components are also configured in an out-of-plane distribution manner with the help of indium pillars; in other words, signal connection and transmission are achieved through indium pillars. That is, the components are configured into two parts, and one part is provided on the upper chip and the other part is provided on the lower chip. At the same time, the indium pillar is also arranged between the upper chip and the lower chip, and the two ends are respectively connected to the two parts of these components.

Therefore, in such a structure, the indium pillar not only plays the role of supporting the two-layer chip, but also serves as a signal transmission line for components distributed in the two parts of the upper and lower chip. Therefore, the quality of indium pillars plays an important role in the normal service of flip-chip soldering chips. Then when making flip-chip soldering superconducting quantum chips, it is necessary to evaluate the performance/quality of the indium pillars in order to obtain flip-chip soldering quantum chips with qualified indium pillars.

In practice, the quality problem of the indium pillar may be due to misalignment of the upper and lower layers of chips during flip-chip soldering, resulting in the indium pillar not being connected to the components corresponding to the upper and lower layers. These problems are not always easily discovered and overcome in the process of making flip-chip chips. Therefore, after the manufacturing process is completed, testing the quality of the indium pillars becomes an important alternative.

However, there is currently no effective solution related to this in the industry. Previously, the inventors tried to judge the quality of lines connected through indium pillars by measuring their DC characteristics. For example, the four-wire bridge method is used to measure the on-off status of the indium pillar to characterize the DC characteristics of the indium pillar. Although these attempts are optional solutions, for superconducting quantum chips, the above solutions do not well reflect the working performance of the quantum chip. Because superconducting quantum chips need to perform measurement and control operations based on radio frequency signals. That is, we hope to evaluate the performance of indium pillars in flip-chip soldered superconducting quantum chips under radio frequency signals. The aforementioned solution based on DC characteristics cannot meet this requirement.

In view of this and this realistic situation, in the example of this application, the inventor proposes an interconnection performance test assembly (which may also be called a test structure).

The interconnection member (also called the first interconnection structure) is, for example, an indium pillar, a commonly used interconnection member in the aforementioned superconducting quantum chip. The interconnects may be other structures in other examples. For example, other forms of interconnects used in flip-chip soldering chips in classical computers (non-quantum chip computers), such as solder bumps, etc. That is, for lines or devices that need to transmit microwave signals and are interrupted by interconnects, in order to evaluate the quality/performance of the interconnects, the solutions illustrated in this application can be selectively applied or modified according to the usage scenario.

The performance mainly refers to the continuity of the resonator when the interconnection parts can normally transmit and transmit microwave signals, and can be characterized by the resonant frequency; further, the performance can also be when the interconnection parts are connected. Quality factor of the resonator. And the quality factor is mainly manifested by the overall components with interconnections, and can also be used as an important criterion or factor for evaluating the performance of interconnections.

Since the performance of interconnects is mainly related to their materials, manufacturing processes, and structural designs, the characterization of their performance through the above methods can also be used to verify that the selection of materials, processes, and structures of interconnects is reasonable or better. .

Generally speaking, an interconnect performance testing component in the example of this application is configured to be used in this way: a detection signal is input to the component through an electronic instrument or device, and the required data is obtained by processing the obtained feedback signal, This allows implementers to use this data to evaluate the performance of the interconnects in the assembly. The electronic instrument is selected according to the detection content to be performed; in the example, it can be selected as a vector network analyzer. The evaluation of performance can be the result of software processing of feedback data by electronic devices and display by display devices, voice devices, etc., or human judgment of the data.

In other words, an evaluation system can be made based on the above-mentioned interconnect performance testing component, which can include a detection signal input device, and is signal-connected to a corresponding component in the component for inputting a detection signal. At the same time, the system also includes signal processing and display equipment. The signal processing device can be integrated into the input device or used as an independent device; the display device can also be an independent device or integrated with a processing device independent of the input device. Generally, the signal processing device can be a microcontroller, FPGA (Field-Programmable Gate Array), programmable logic controller, etc.

The interconnect performance testing components in the examples of this application will be described below with reference to the accompanying drawings.

Figure 6 discloses the layout structure of the interconnect performance test component in the example. FIG. 7A discloses a schematic cross-sectional structural view of a resonant cavity (also known as a resonant element) configured with an interconnect 3033 in the interconnect performance testing assembly at the location of the interconnect.

Please refer to Figure 6 and Figure 7A together. Generally, the interconnect performance testing assembly includes a first chip 401, a second chip 402, at least two resonant cavities, and a first microwave transmission line 301 (also known as the first electrical component 301) .

The first chip 401 and the second chip 402 are configured in a close and opposite manner, and in order to facilitate the connection and data communication between the chips made based on them and external devices, the size of one chip is usually smaller than the other chip. size of. For example, the size of the first chip 401 is smaller than the size of the second chip 402 . Then, in the case of an opposing layout, the aforementioned interconnect 3033 is generally disposed at a selected position within the area where the second chip 402 covers the first chip 401 . The area of the second chip 402 that is not covered by the first chip 401 can be used as an area where pads, interfaces, etc. connected to the aforementioned external devices are provided. The interconnection 3033 is located between the first chip 401 and the second chip 402 (see FIG. 7B ), thereby playing a role of connection and support. And further, it also serves as a component of a partial resonant cavity, so that microwave signals can be transmitted.

The at least two resonant cavities described are configured as two types of resonant cavities. The number of resonant cavities of the same type may be one or more, and the number of two types of resonant cavities may be the same or different. In different examples, the resonant cavity may be in various specific forms, for example, it may be selected as a half-wavelength resonant cavity or a quarter-wavelength resonant cavity. Moreover, the resonant cavity may also be a coplanar waveguide resonant cavity or a three-dimensional resonant cavity. It is based on superconducting quantum chips and can use superconducting materials such as aluminum (Al), niobium (Nb), etc. Similarly, microwave transmission lines can also be made of superconducting materials such as aluminum.

It is worth pointing out that in a superconducting quantum chip, when the resonant cavity is made of aluminum and the interconnect 3033 is made of indium, indium and aluminum may cause the formation of an alloy, thereby affecting the superconducting properties of the aluminum, thereby affecting the performance of the qubit. Performance is adversely affected. Therefore, a barrier layer 3034, such as tantalum nitride, is typically passed between the aluminum resonant cavity and the indium interconnect 3033, see FIG. 7B.

Among the above two types of resonators, one type is a resonant cavity that is not configured with an interconnection member 3033. For convenience of description and distinction, it may be called a continuous resonant cavity 302 or a reference resonant element 302, for example. When there are multiple continuous resonant cavities 302, the structure of each continuous resonant cavity 302 is generally the same.

Another type is a resonant cavity configured with an interconnect 3033, which may be called a segmented resonant cavity 303 or a resonant element under test 303 for convenience of description and distinction. This type of resonant cavity is therefore interrupted by interconnections 3033 and thus forms a multi-segment structure (at least two) which are connected in turn by interconnections 3033 . When there are multiple segmented resonant cavities 303 , the number of interconnections 3033 corresponding to each of these resonant cavities and their positions on the extended trajectory in the resonant cavity may be configured in the same manner, or each may be configured in a different manner. .

Based on the above-mentioned continuous resonant cavity 302 and segmented resonant cavity 303, in a flip-chip interconnection chip (having a stacked upper chip and may correspond to the first chip 401 mentioned later, and a lower chip and may correspond to the first chip 401 mentioned later, In two chips 402), the continuous resonant cavity 302 is usually configured to one of the chips, or in other words, on the same surface of one of the chips.

At the same time, due to the configuration of the interconnectors 3033 and according to the function of the interconnectors 3033, the segmented resonant cavity 303 has multiple segments (corresponding to different numbers of segments according to the number of interconnectors 3033), and these segments pass through the interconnections 3033. Connector 3033 for series connection. Therefore, these segments in the segmented resonant cavity 303 are sequentially assigned to upper chips and lower chips; that is, parts of these segments It is a layer of chips distributed or co-planar with it, and the remaining part is another layer of chips distributed or co-planar with it. Taking a segmented resonant cavity 303 with an interconnection 3033 as an example, it has two sections, namely a first element 3031 and a second element 3032; as shown in Figure 6 . Taking a segmented resonant cavity 303 with two interconnectors 3033 as an example, it has three sections, which are respectively the first element, the second element and the third element, see FIG. 10 and FIG. 11 .

As a signal transmission structure for measuring the resonant frequency and quality factor of the resonant cavity, the first microwave transmission line 301 in the interconnect performance testing assembly is coupled to each of the above resonant cavities respectively (it can be at the end of the resonant cavity, that is, at the coupling position. At , the resonant cavity is parallel to the microwave transmission line and spaced at an appropriate distance; the coupling method (for example, capacitive coupling) realizes microwave signal correlation. At the same time, the first microwave transmission line 301 is provided on the first chip 401. Therefore, it can be coplanar with the first element 3031 of the continuous resonant cavity 302 and the segmented resonant cavity 303 respectively on the first chip 401. That is, the microwave transmission line and each resonant cavity are coplanarly coupled.

In the structure shown in FIG. 6 , an interconnection 3033 partitions its corresponding resonant cavity into a first element 3031 and a second element 3032 . Also, the interconnect 3033 is closer to the first microwave transmission line 301 such that the length of the first element 3031 is significantly smaller than the length of the second element 3032. In other examples, such as shown in FIG. 8 , the position of the interconnection 3033 in the segmented resonant cavity 303a is controlled to be further away from the first microwave transmission line 301, so that the length of the first element 3031a is significantly longer than that of the second element 3032a. length.

In short, the segmented resonant cavity 303, when configured with an interconnection, can be configured by changing the position of the interconnection so that the lengths of the first element and the second element are relatively sized—equal or optionally of different sizes— configuration. Furthermore, for the case where there are multiple segmented resonant cavities 303 and each is configured with an interconnection member 3033, the position of each interconnection member 3033 may also be the same or the same.

FIG. 9 illustrates a situation in which interconnectors 3033 in two segmented resonant cavities 303 each having one interconnector 3033 are arranged at different positions. Moreover, FIG. 9 further discloses the configuration of two microwave transmission lines (also called electrical components). Therefore, the assembly may include a first microwave transmission line 301 and a second microwave transmission line 502 (also called a second electrical component).

In addition, since the continuous resonant cavity 302 is not provided with the interconnection 3033, it is configured in a layer of chips in a flip-chip chip, such as the aforementioned first chip 401. Then, in an example, the second microwave transmission line 502 can also be configured to the first chip 401, so that it can be coplanar with the first microwave transmission line 301 on the first chip 401.

As shown in FIG. 9 , the two microwave transmission lines roughly have the same extension direction and are spaced apart from each other. Therefore, from the perspective of the layout structure and the projection pattern of the same plane, each resonant cavity is located between the two microwave transmission lines. Both ends of the continuous resonant cavity 302 are coupled to two microwave transmission lines respectively. Correspondingly, the two ends of the segmented resonant cavity 303 are also coupled to both of them respectively.

Referring to Figure 10, for the case of having two interconnects 3033 per segmented resonant cavity 303, the first element and the third element are respectively coupled to two microwave transmission lines. The segmented resonant cavity 303 in FIG. 10 is divided into three elements by two interconnections 3033 respectively, in which the first element and the third element have approximately equal lengths and are respectively smaller than the second element. In other examples, the individual elements may be configured to other lengths.

As mentioned above, the quality of the interconnect 3033 may be related to the alignment of upper and lower chips in the flip-chip interconnect chip. Therefore, when the resonant cavity is configured with multiple interconnections 3033, the alignment accuracy is usually required to be higher. Therefore, in some examples, you can also choose to configure multiple physical components around the interconnections 3033, which can not only play the role of It assists in the alignment of the upper and lower chips to be flip-chip interconnected, and can also play a role in supporting the upper and lower chips. The physical component may also be a combined structure of indium pillars and titanium nitride, for example. That is, titanium nitride layers are configured at both ends of the indium pillar; the titanium nitride layer is also bonded to the surface of the upper and lower chips and does not contact the resonant cavity and microwave transmission line.

In Figure 11, four support posts 3035 are distributed around each interconnect 3033. The number of supporting columns may be less than or more than four. The four support pillars 3035 are annularly distributed around the interconnect 3033, and each support pillar 3035 includes an indium pillar and titanium nitride at both ends thereof. It is worth noting that although the support column 3035 is described above, it does not mean that it only exists as a supporting structure.

Based on the above interconnection performance testing components, the following solutions can be implemented for testing operations. For example, a vector network analyzer is connected to the microwave transmission line on the component, the test component is tested and the measurement data is recorded, and the obtained measurement data is processed to obtain the corresponding target parameters—resonant frequency and quality factor.

The following analysis can be performed based on the resonant frequency and quality factor:

During the measurement process, since the continuous resonant cavity 302 is not provided with interconnections, it is not interrupted, so that the resonant frequency can always be measured.

When the interconnections 3033 of the segmented resonant cavity 303 are connected, the resonant frequency of the entire resonant cavity can be measured.

For the case where the interconnects of the segmented resonator 303 are disconnected:

Considering that the frequency of the resonant cavity is related to its length, in some examples, the interconnections 3033 of the segmented resonant cavity 303 are positioned such that different elements (such as the first element 3031 , the second element 3032 , the third element 3032 ) therein are components, etc.) the length is too For a short period of time, the resonant frequency of the corresponding component will exceed the measurement limit of the instrument, which means that the actual effective resonant frequency cannot be measured. Because the measurement is carried out through microwave transmission lines. Therefore, when interconnect 3033 is open, what is actually being measured is the component directly coupled to it. Then, when the element is too short, the resonant frequency of the entire segmented resonant cavity 303 cannot be measured.

Or when the interconnection 3033 of the segmented resonant cavity 303 is disconnected but the length of the element directly coupled to the microwave transmission line is appropriately selected, its resonant frequency can still be measured, although its value will deviate from the interconnection due to the length of the section. 3033 resonant frequency when connected. When the interconnection 3033 of the segmented resonant cavity 303 is disconnected but the length of the component directly coupled to the microwave transmission line is very short, it is difficult to measure the resonant frequency of the component and the resonant frequency of the entire resonant cavity cannot be measured.

Based on the above analysis, for the example of measuring the resonant frequency, when the resonant frequency of a segmented resonant cavity 303 cannot be measured, it indicates that its corresponding interconnection 3033 is disconnected, so the quality of the interconnection 3033 is poor. . When the resonant frequency of a certain segmented resonant cavity 303 can be measured, it can be compared with the resonant frequency of the continuous resonant cavity 302 . If the comparison result is that the difference between the two is close or equal as expected, it can also be considered that the interconnections 3033 of the segmented resonant cavity 303 are connected and therefore of good quality. On the contrary, if although the frequency of the resonant cavity can be measured, the difference between its structure and the resonant frequency of the continuous resonant cavity exceeds expectations, it can also be considered that the interconnect 3033 is disconnected and of poor quality.

Furthermore, when it is confirmed that the interconnections 3033 of the segmented resonant cavity 303 are connected, their quality factor can also be measured, and the higher the quality factor, the better the connectivity of the interconnections 3033. Moreover, the measured quality factor of the segmented resonant cavity 303 can also be compared with the quality factor of the continuous resonant cavity 302 in order to obtain the segmented resonant cavity 303 with a quality factor that better meets the requirements.

Embodiment 3: Test the continuity or connectivity of the air bridge.

In complex microwave electronic systems, the layout of various circuits and devices is becoming more and more difficult, so their crossover has become a common status quo. In the low-frequency field, the size of the entire system and the various lines and devices in it are relatively large. Therefore, in order to avoid adverse effects at the crossover location, jumpers can be used to "skip" the crossover location. However, when the above-mentioned system operates in the high-frequency domain, then using jumpers to skip the crossover position has achieved the desired effect. Moreover, in terms of space size, in the high-frequency field due to the small size of circuits and devices, the connection of the jumper may not be too stable. In this realistic context, air bridges were proposed and used. The air bridge can realize high-speed interconnection; it can be used as a ground plane and an internal connection for various active or passive devices, and has little impact on the inductance and capacitance of the system under high-frequency conditions.

In an important application, air bridges are used in transmission lines such as Coplanar Waveguide (CPW) to make connections in their discontinuous areas. In the field of superconducting quantum chips, as the number of qubits continues to increase, air bridges also need to be configured at the intersections of coplanar waveguide transmission lines to avoid direct cross contact of coplanar waveguide transmission lines.

Please refer to Figure 12. According to the direction shown in Figure 12, the continuously extending first coplanar waveguide 601 is distributed in the vertical direction; the discontinuous second coplanar waveguide 602 interrupted by the air bridge 603 is distributed in the horizontal direction. Correspondingly, the air bridges 603 are also distributed in the horizontal direction. The two parts resulting from the second coplanar waveguide 602 interrupted by the air bridge 603 - the first sub-segment 6021 and the second sub-segment 6022 - are connected to each other via this air bridge 603. Therefore, the air bridge 603 is connected across the first coplanar waveguide 601 to the first sub-section 6021 and the second sub-section 6022 on both sides of the interrupted region 74 of the second coplanar waveguide 602 .

It is worth pointing out that although the use of the air bridge 603 is described in this section in the form of criss-crossing coplanar waveguides. However, this does not mean that the surface air bridge 603 can only be used where there are intersections between lines or devices.

In the application scenario of superconducting quantum chips, it is necessary to judge the production quality in order to eliminate unqualified air bridges. For example, it is necessary to determine whether a disconnection has occurred; if it is, it is necessary to consider adjusting the process or design plan. One test method that is easy to choose and implement is to characterize DC characteristics.

However, the working mode of superconducting quantum chips determines that it requires the participation of radio frequency signals. It is therefore necessary to characterize the performance of the air bridge with respect to RF signals. And it can be seen that the aforementioned method of characterizing DC characteristics cannot meet the needs of RF signal characterization. At the same time, on the other hand, the method of characterizing radio frequencies through insertion loss, reflection, etc. is also difficult to implement and develop conveniently in superconducting quantum chips. Because superconducting quantum chips need to work at extremely low temperatures, which usually require the use of dilution refrigerators, and the chips are equipped with various radio frequency devices. Furthermore, the air bridge used in superconducting quantum chips is usually selected as a superconducting material, so its insertion loss and reflection are also small, and radio frequency characterization is difficult.

Therefore, in order to achieve the characterization of the performance of the air bridge used in the superconducting quantum chip with respect to radio frequency signals, the inventor proposed an easy-to-implement solution. Considering that in superconducting quantum chips, the system of reading bus, reading resonant cavity and qubit is used to realize the operation and control of qubits, the inventor chose to propose a method that can be implemented as reading bus and reading resonance. Cavity coupling system, and the read resonant cavity is configured based on an air bridge. Therefore, it can be understood that the read resonant cavity in the coupling system is configured as a plurality of segmented parts, for example two parts. Therefore, there are interruption areas between any two of these multiple parts; then in these interruption areas, configured air bridges are provided and both ends of the air bridge are connected to the reading resonant cavities on both sides.

Based on this, by inputting microwave signals to the read bus and the read resonant cavity with an air bridge, and then interpreting the resonant frequency and quality factor of the read resonant cavity from the feedback signals, the resonant frequency and quality factor of the read resonant cavity can be analyzed accordingly. About air bridge Characterize the performance of RF signals. In order to facilitate and simplify the evaluation of the resonant frequency and quality factor obtained above, in the example of this application, an additional reading resonant cavity is also configured, which can be used as a "standard part" to provide reference parameters. That is, the resonant frequency and quality factor of the standard part are used as reference values to compare the resonant frequency and quality factor measured by the reading resonant cavity equipped with an air bridge.

Based on the above understanding, this application example proposes an air bridge test assembly (also known as a test structure). Please refer to Figures 13 and 14 for its structure. It includes a microwave signal line, which is described as a first microwave signal line (also called a first electrical component) 70 for purposes of distinction. The component further includes a plurality of resonant cavities or resonant elements (each of which can be independently a half-wavelength resonant cavity or a quarter-wavelength resonant cavity), for example at least two. And the resonant cavities in the component are defined into two types according to whether the air bridge 73 is configured, one of which is the first type of resonant cavity without the air bridge 73 (i.e., the first interconnection structure) (hereinafter referred to as the first resonant cavity 71 An example of the resonant cavity is recorded, which may also be called a reference resonant element), and another one of them is a second type resonant cavity configured with an air bridge 73 (subsequently described as an example of the second resonant cavity 72, which may also be called a reference resonant element). Measure resonant components). The first type of resonant cavity may be designed according to the structure and material selection of the first resonant frequency, while the second type of resonant cavity may be designed according to the structure and material selection of the second resonant frequency. It should be pointed out that the above-mentioned first resonant frequency and second resonant frequency are design parameters of the resonant cavity. This design parameter can usually be obtained through simulation design using software such as HFSS; there may be a certain difference between its value and the measured value obtained after the resonant cavity is actually manufactured.

In the example of this application, as an application example in a superconducting quantum chip, the resonant cavity can be selected as a coplanar waveguide structure. Therefore, in the second type of resonant cavity, both ends of the air bridge 73 are respectively connected to the central conductor strip of the resonant cavity in the form of a coplanar waveguide.

For convenience of description and understanding by those skilled in the art, the first direction and the second direction are defined. The first direction X is, for example, a horizontal direction, and the second direction Y is, for example, a vertical direction, and based on this, each part in the assembly is positioned.

In FIG. 13, the first microwave signal line 70 extends in the first direction X. The two resonant cavities, namely the first type resonant cavity and the second type resonant cavity, are spaced apart in the first direction and have a distance between them.

Each resonant cavity extends along the second direction Y from the first end to the second end. Each resonant cavity has its first end adjacent to the first microwave signal line 70 (correspondingly, its second end is far away from the first microwave signal line 70), and its first end is coupled to the first microwave signal line 70. One of the two resonant cavities is described as a first resonant cavity 71 and the other as a second resonant cavity 72 ; therefore, an air bridge 73 is provided to the second resonant cavity 72 .

Figure 14 is a partial enlarged view of part A in Figure 13; as shown in Figure 14, the second resonant cavity 72 has an interruption region 74, and the interruption region 74 has a preset width in the second direction. The air bridge 73 spans the interruption area 74 , and its two ends are respectively connected to the second resonant cavity 72 at two ends of the interruption area 74 . It can be known that when a resonant cavity has multiple air bridges 73 , the resonant cavity will accordingly have multiple interruption regions 74 ; that is, one interruption region 74 corresponds to one air bridge 73 .

In the case of an assembly with a plurality of second resonant cavities 72 , the number and position of the air bridges 73 configured in each second resonant cavity 72 can be configured in the same manner. That is, the position and number of the air bridges 73 in each second resonant cavity 72 can be configured according to the requirements of any test. Since the interruption area 74 and the air bridge 73 have a one-to-one correspondence, the position of the air bridge 73 corresponds to the position of the interruption area 74 . For example, with reference to FIG. 13 and FIG. 15 , for the case of having at least the second resonant cavity 72 , the interruption region 74 of part of the resonant cavity can be configured to the first end, while the interruption of the remaining second resonant cavity 72 Area 74 is located at the second end.

In this assembly, the first microwave signal line 70, the two resonant cavities and the air bridge 73 are coplanar. That is, the three are respectively fabricated on the same substrate 801 or one surface of the substrate; for example, formed on the surface of the substrate. For obtaining microwave signal lines, resonant cavities and air bridges, those skilled in the art can use semiconductor processes to produce them, and usually combine coating, etching, photolithography, stripping and other means, which will not be described again here.

Based on the above component structure, in some other examples, partial adjustments can be made to obtain component structures in various deformed forms. For example, the main difference between the assembly shown in Fig. 15 and the assembly shown in Fig. 13 is that the position of the air bridge 73 of the second resonant cavity 72 in Fig. 15 is at a position far away from the first microwave signal line 70, for example, approximately At or near the second end. The difference is that in the second resonant cavity 72 shown in FIG. 13 , the air bridge 73 is located close to the first microwave signal line 70 , for example, approximately at or near the first end.

It should be understood that, in addition to being disposed at the above-mentioned positions of the second resonant cavity 72—the first end and the second end—the air bridge 73 can also be disposed at any selected position between the first end and the second end. Alternatively, more, for example, at least two second resonant cavities 72 may be configured in the assembly; the positions of the respective air bridges 73 in these resonant cavities may be selected in any manner.

Furthermore, in addition to adjusting the position of the air bridge 73 in the second resonant cavity 72, other adjustment methods can also be selected, such as configuring multiple, such as two, microwave signal lines in the component independently or in combination with the above air bridge position solution. . Exemplarily, as shown in Figure 16, the assembly includes a first microwave signal line 70 and a second microwave signal line 80 (also called a second electrical component), which extend along the first direction The preset distance in the second direction. It is understandable that this distance The distance is usually appropriately selected according to the lengths of the first resonant cavity 71 and the second resonant cavity 72 .

Furthermore, the two ends of each resonant cavity, namely the first end and the second end, are coupled to the first microwave signal line 70 and the second microwave signal line 80 respectively. In such an example, since the resonant cavity is coupled to two microwave signal lines respectively, the two microwave signal lines can be used to adjust the resonant frequency of the entire resonant cavity or different parts according to the position of the air bridge 73 . Measurement.

When there are two microwave signal lines distributed in the above manner, it will be more helpful to test a resonant cavity with multiple air bridges 73, for example, as shown in Figure 16.

In the above example, the adjustment scheme for the number of the second resonant cavities 72 in the test assembly and the position and number of the air bridges 73 is mainly described. The structure of the air bridge 73 will be described below. By improving the structure of the air bridge, its performance can be adjusted, thereby helping to select a resonant cavity with better target performance and configured with the air bridge 73 . For example, the number, position and structural parameters of the air bridges 73 are used as inspection indicators. In some specific examples, two of the indicators are fixed and another indicator is changed, thereby screening the air bridges 73 . For example, for the second resonant cavity 72, the number, position and structure of the air bridges 73 of some of the resonators are the same, and therefore are defined as the first resonant cavity subset; the number and position of the air bridges of the remaining resonators are and structures, and is therefore defined as the second resonant cavity subset. Therefore, the structure of the respective air bridges 73 in the first subset of resonant cavities 71 is different from the structure of the respective air bridges 73 in the second subset of resonant cavities 72, but the number and position of the air bridges in the two subsets correspond to each other.

As an example, please refer to Figures 14 and 17 together. Figure 17 discloses an axial side view of the air bridge 73 having a generally arched structure. The air bridge has a width dimension D1 defined along the first direction X, and a length dimension D2 defined along the second direction Y; and the length dimension D2 is greater than the width dimension D1. It will be appreciated that in other examples, the length and width dimensions may be configured opposite or different from those described above.

Please refer to FIG. 17 again, the air bridge 73 is divided into three parts, and is a first end part 731, a transition part 733, and a second end part 732 that are connected in sequence. Among them, near the interruption area 74, the first end 731 and the second end 732 of the air bridge 73 are coplanar with the two ends of the resonant cavity (located on the front or first surface of the substrate 801, that is, on the same side) and connect. And the transition portion 733 therein is away from the first plane, thereby forming a gap. In this example, the transition 733 of the air bridge 73 spans the interruption region 74 in the manner of an arch and therefore has a gradual slope relative to the first plane. For comparison, the air bridge 73 in Figure 18 can be considered to have an infinite slope, while the air bridge 73 in Figure 19 can be considered to have a constant slope.

In the above examples, the air bridge 73 is configured as a substantially arch structure, and in other examples it may also be configured as a substantially rectangular structure, as shown in FIG. 18 . In Figure 18, the air bridge 73 has a generally rectangular structure. One end of the transition portion 733a rises vertically from the first end 731 away from the first surface, then forms a horizontal extension, then vertically descends close to the first surface and terminates at the surface of the second end 732 The other end of transition portion 733 is formed.

In yet other examples, the air bridge 73 may also be configured to have a generally trapezoidal structure, as shown in FIG. 19 . The transition portion 733b includes a first section 901, a second section 902 and a third section 903, and the three sections are connected in sequence; the second section 902 is parallel to the first plane. Moreover, the first section 901 gradually climbs from the first end 731 to the second section 902, while the third section 903 gradually climbs from the second end 732 to the second section 902.

The test method based on the above air bridge test assembly can be implemented as follows:

Connect the air bridge test assembly to a device such as a vector network analyzer for testing. The vector network analyzer generates a test signal as an excitation and inputs it into the device under test (DUT) - in this case, the air bridge test component - and then characterizes its network by analyzing the feedback signal changes generated by the excitation signal passing through the DUT. Characteristics, so that the resonant frequency, quality factor, etc. of the resonant cavity can be measured.

In the solution of this example, the test may include only measuring the resonant frequency, or only measuring the quality factor, or measuring both the resonant frequency and the quality factor. When both the resonant frequency and the quality factor are measured, you can choose to first obtain the second resonant cavity 72 with good connectivity of the air bridge 73 through resonant frequency measurement, and then select the second resonant cavity 72 with good connectivity based on the first resonant cavity 71 and the resonant frequency measurement. One or more second resonant cavities of the air bridge 73 with good performance are tested.

In the above test, the connectivity of the air bridge 73 can be tested by testing the first resonant cavity 71 and the second resonant cavity 72, and comparing and judging the measured resonant frequencies of the two resonant cavities.

When the number of resonant cavities is not equal to the number of measured resonant frequencies, it can be determined that the air bridge 73 is not connected.

When the number of resonant cavities is equal to the number of measured resonant frequencies, it can be determined that all air bridges 73 are connected. It is worth pointing out that since the resonant frequency of the resonant cavity is related to its length, and the frequency of the resonant cavity with a length that is too small is very high, it can be considered a non-measurable value, and thus the resonant frequency cannot be measured. In other words, when the air bridge 73 is in a non-connected state and the length of the portion of the resonant cavity coupled to the microwave signal line is appropriate, the resonant frequency can also be measured. Therefore, in order to avoid the determination of the test results in this situation, the position of the air bridge 73 in the second resonant cavity 72 can be controlled so that the second The length of the portion of the microwave signal line 80 coupled to the microwave signal line is appropriately selected so that when the air bridge 73 is not connected, the resonant frequency will be undetectable.

After the second resonant cavity 72 connected to the air bridge 73 is determined in the above manner, the quality factor is measured to obtain the second resonant cavity 72 connected to the air bridge 73 and with a higher quality factor. At this time, the first resonant cavity 71 and the second resonant cavity 72 that have been confirmed to be connected by the air bridge 73 can be measured together, and the second resonant cavity 72 with a higher quality factor can be selected as the confirmed air bridge 73's effect on the radio frequency signal. Instances with high connectivity quality. The quality factor of the second resonant cavity can be used to determine the connection quality of the air bridge to the radio frequency signal in the connected state.

The embodiments described above with reference to the drawings are exemplary and are only used to explain the present application and cannot be construed as limiting the present application. In order to make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the foregoing contents are described in detail in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in each embodiment of the present application, many technical details are provided to enable readers to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in this application can also be implemented. The division of each example is for the convenience of description and should not constitute any limitation on the specific implementation of the present application. The various embodiments can be combined with each other and quoted from each other on the premise that there is no contradiction.

It should be noted that the terms "first", "second", etc. in the description and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances so that the embodiments of the application described herein can be practiced in sequences other than those illustrated or described herein.

In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, e.g., a process, method, system, product, or apparatus that encompasses a series of steps or units and need not be limited to those explicitly listed. Those steps or elements may instead include other steps or elements not expressly listed or inherent to the process, method, product or apparatus.

The structure, features and effects of the present application have been described in detail based on the embodiments shown in the drawings. The above descriptions are only preferred embodiments of the present application. However, the scope of implementation of the present application is not limited by the drawings. Any changes made to the concept of this application, or modifications to equivalent embodiments with equivalent changes, shall be within the protection scope of this application as long as they do not exceed the spirit covered by the description and drawings.

Claims

A test structure of a superconducting quantum chip, characterized in that the test structure is used to test the first interconnection structure in the superconducting quantum chip, and the test structure includes:

a reference resonant element having a first design resonant frequency;

The resonant element under test has a first element and a second element configured to be connected through the first interconnection structure and in different planes, the resonant element under test is configured based on design parameters, and the design parameters are based on the The first design resonant frequency is preset and generated;

A first electrical component is independently coupled to the first component of the reference resonant component and the resonant component under test.
The test structure of claim 1, wherein the first interconnection structure is a through silicon via interconnection structure, and the test structure is used to determine the connectivity of the through silicon via interconnection structure.
The test structure according to claim 1 or 2, characterized in that the first electrical element is configured to receive a detection signal to determine the measured value of the resonant frequency of the measured resonant element and the reference resonant element. The measured value of the resonant frequency.
The test structure according to claim 3, characterized in that the test structure includes at least two groups of measured resonant elements configured independently, and each group includes at least one measured resonant element;

Each of the first elements has a first parameter, each of the second elements has a second parameter, and the first parameter and the second parameter jointly determine the resonant frequency of the resonant element under test;

Wherein, the first parameters of each measured resonant element in the same group are the same, and the first parameters of the measured resonant elements in different groups are different.
The test structure of claim 4, wherein the first parameter is the length of the first element, and the second parameter is the length of the second element.
The test structure according to any one of claims 1 to 5, characterized in that the test structure further includes a second circuit element independently connected to the reference resonant element and the measured resonant element. second element coupling;

The second circuit element is configured to receive a detection signal to determine a measurement of the resonant frequency of the resonant element under test and a measurement of the resonant frequency of the reference resonant element.
The test structure according to claim 6, wherein the resonant element under test includes a first section element, a second section element and a third section element connected in sequence through two first interconnect structures;

Wherein, the first segment component is coupled with the first electrical component, and the third segment component is coupled with the second circuit component;

Wherein, the first section element and the second section element are provided by the first element, and the third section element is provided by the second element; or, the first section element is provided by the first element provided, and the second section element and the third section element are provided by the second element.
The test structure of claim 7, wherein the first section of components and the third section of components are coplanarly arranged.
The test structure according to any one of claims 6 to 8, wherein the reference resonant element and the first electrical element are coplanarly arranged;

And/or, the first element and the first electrical element are arranged in the same plane, and the second element and the second circuit element are arranged in the opposite plane;

Alternatively, the resonant element under test has a second design resonant frequency, and the first design resonant frequency is equal to the second design resonant frequency or the difference is within a given range.
The test structure according to claim 1, wherein the test structure includes at least two resonant elements, and the at least two resonant elements include the reference resonant element and the measured resonant element, and the test structure Also includes:

first chip;

a second chip, opposite to the first chip;

At least one of the first interconnect structures is located between the first chip and the second chip;

The reference resonant element is configured on the first chip, and each of the resonant elements under test is independently interrupted by the first interconnection structure, thereby forming a first interconnection structure connected through the first interconnection structure. An element and a second element, wherein the first element is configured on the first chip and the second element is configured on the second chip; and

The first electrical component is disposed on the first chip, and the first electrical component is configured to couple to the reference resonant element and to couple to each of the first elements of the measured resonant elements.
The test structure of claim 10, wherein the first element has a first length associated with a resonant frequency of the first element and the second element has a resonant frequency associated with the second element. A second length of frequency, and the first length and the second length are different.
The test structure according to claim 10 or 11, characterized in that the length of the first element of each of the resonant elements under test is different.
The test structure of any one of claims 10 to 12, wherein each of the resonant elements is parallel to and spaced apart from the first electrical element at a location coupled to each other. layout.
The test structure according to any one of claims 10 to 13, characterized in that the test structure further includes a second electrical element. component, the second electrical component is configured on the first chip, and is spaced apart from and extending in parallel with the first electrical component;

Two ends of the reference resonant element are respectively coupled to the first electrical element and the second electrical element.
The test structure according to claim 1, wherein the test structure includes at least two resonant elements, and the at least two resonant elements include the reference resonant element and the measured resonant element, and the test structure include:

first chip;

a second chip, opposite to the first chip;

The reference resonant element is configured on the first chip, and each of the measured resonant elements is independently interrupted by the corresponding first interconnection structure and the second interconnection structure, thereby forming a path through the first interconnection structure. An interconnection structure and a first element, a second element and a third element connected in series in sequence, wherein the first element and the third element are configured on the first chip, the A second component is configured on the second chip; and

A pair of electrical components coplanar to the first chip and spaced side by side, the pair of electrical components including the first electrical component;

Two ends of the reference resonant element are respectively coupled to the pair of electrical elements, and the first element and the third element of each of the measured resonant elements are coupled to the pair of electrical elements respectively.
The test structure of claim 15, wherein the first element and the third element are equal in length.
The test structure of claim 15 or 16, wherein the length of the second element is greater than the length of the first element, and the length of the second element is greater than the length of the third element.
The test structure according to any one of claims 10 to 17, wherein the reference resonant element and/or the measured resonant element is a half-wavelength resonant element or a quarter-wavelength resonant element.
The test structure according to any one of claims 10 to 18, wherein the first interconnection structure is surrounded by a plurality of supporting columns arranged at intervals in an annular manner.
The test structure of claim 1, wherein the first electrical element extends along a first direction, the reference resonant element and the measured resonant element belong to a plurality of resonant elements, and the plurality of resonant elements Arranged at intervals along the first direction, each resonant element extends from the first end to the second end along a second direction different from the first direction;

The first interconnection structure is an air bridge, and the air bridge is coplanar with the first electrical component, the reference resonant component, and the measured resonant component;

Each resonant element has a first end adjacent to and coupled to the first electrical element;

Each resonant element under test among the plurality of resonant elements has an interruption area of a given width along the second direction, and the corresponding interruption area is bridged by the air bridge.
The test structure of claim 20, wherein the test structure further includes a second electrical component coplanar with the first electrical component, and the second electrical component extends along the first direction;

In the second direction, the second electrical component is spaced apart from the first electrical component;

The first end of each resonant element is adjacent to and coupled to the first electrical element, and the second end of each resonant element is adjacent to and coupled to the second electrical element.
The test structure according to claim 20 or 21, characterized in that each of the resonant elements under test has an interruption region, and the position of the interruption region of each resonant element is different.
The test structure according to claim 20 or 21, wherein the interruption area of one or more of the resonant elements under test is located at the first end, The interruption areas of the remaining resonant elements are located at the second end.
The test structure of claim 20 or 21, wherein each of the resonant elements under test has at least two interruption areas.
The test structure of claim 24, wherein the number of interruption areas of each of the resonant elements under test is the same;

And/or, the positions of at least part of the interruption areas of each of the resonant elements under test are the same.
The test structure according to any one of claims 20 to 25, wherein among the reference resonant element and the measured resonant element, the measured resonant element has a first target resonant frequency defined, so The reference resonant element defines a second target resonant frequency, the first target resonant frequency is different from the second target resonant frequency and the difference is within a preset range;

And/or, the resonant element is a half-wavelength resonant element or a quarter-wavelength resonant element.
The test structure according to any one of claims 20 to 26, wherein the air bridge has structural parameters, and the resonant element under test includes a first resonant element subset and a second resonant element subset, so The first subset of resonant elements has at least one resonant element, and the second subset of resonant elements has at least one resonant element;

The first resonant element subset and the second resonant element subset have the same number and the same position of the interruption regions of the resonant elements, and the corresponding structural parameters of the air bridge are different.
The test structure according to any one of claims 20 to 27, wherein the air bridge has a width dimension defined along the first direction and a length dimension defined along the second direction, said The length dimension is greater than the width dimension.
The test structure according to any one of claims 20 to 28, wherein the air bridge has a first end, a transition part and a second end connected in sequence; in the interruption area, the One end and the second end are respectively coplanar and connected to the two ends of the resonant element;

The resonant element is arranged on a first plane, the transition portion is away from the first plane to form a gap, and the transition portion has a gradual slope relative to the first plane.
The test structure according to any one of claims 20 to 29, wherein the air bridge has a first end, a transition part and a second end connected in sequence; in the interruption area, the One end and the second end are respectively coplanar and connected to the two ends of the resonant element;

The resonant element is arranged on the first plane, and the transition portion is away from the first plane to form a gap;

The transition portion includes a first section, a second section and a third section connected in sequence, the second section being parallel to the first plane;

From the first end to the second section, the first section gradually climbs,

From the second end to the second section, the third section gradually climbs.
A test structure of a superconducting quantum chip, used to determine the connectivity of the through silicon via interconnection structure in the superconducting quantum chip, characterized in that the test structure includes:

Read the bus and extend along the first preset direction;

At least one interconnection unit, and each interconnection unit includes n interconnection structures, n is an integer greater than or equal to 1; and

At least one resonator arranged side by side and spaced apart along the first preset direction, the at least one resonator being at least one resonator corresponding to the at least one interconnection unit;

Each resonator is manufactured according to the designed resonant frequency parameters, and each resonator extends from the first end to the second end along a second preset direction that is different from the first preset direction;

Each of the resonators is interrupted by the interconnection structure in the corresponding interconnection unit to form m sub-elements, and m=n+1; wherein the m sub-elements pass through the interconnection structure in the interconnection unit. The connection structures are connected in turn, and the resonator is coupled to the read bus through the sub-element located at the first end.
The test structure of claim 31, wherein the read bus and the resonator are respectively coplanar waveguides;

and/or, in the at least one interconnection unit, there are at least two interconnection units with different numbers of interconnection structures;

And/or, the test structure includes a reference resonant element with a given resonant frequency, the reference resonant element is extended and arranged along the second preset direction, and the reference resonant element is coupled with the read bus.
The test structure according to claim 31 or 32, characterized in that the test structure includes two read buses, and the two read buses are arranged in parallel and at intervals;

The sub-element at the first end and the sub-element at the second end of each resonator are respectively coupled to the two read buses.
The test structure according to any one of claims 31 to 33, characterized in that the test structure includes a reference resonant element with a given resonant frequency, and two ends of the reference resonant element are respectively connected to the two reading wires. Take the bus coupling.
The test structure of any one of claims 31 to 34, wherein the test structure is used to implement a test method to determine the connectivity of the through silicon via interconnect structure.
A testing method for superconducting quantum chips, used to determine the connectivity of through silicon via interconnect structures in superconducting quantum chips, characterized in that the testing method includes:

Obtain a test structure, the test structure has a first electrical element, a reference resonant element and a measured resonant element, the first electrical element is coupled with the reference resonant element; wherein the measured resonant element is based on the mutual The reference resonant element is made of the reference resonant element with an interrupted connection structure, and the resonant element under test has a proximal element and a distal element connected through the interconnection structure and in different planes, and the resonant element under test is connected through the near-end element. a terminal element coupled to the first electrical element;

Transmitting a microwave detection signal to the reference resonant element and the measured resonant element through the first electrical element;

Using the feedback signal obtained from the first electrical component, calculate the reference resonant frequency of the reference resonant component and the measured resonant frequency of the measured resonant component to form a resonant frequency result set;

Confirming connectivity of the interconnect structure according to a preset pattern based on the set of resonant frequency results.
The testing method according to claim 36, wherein the preset mode includes:

When the number of measured resonant frequencies in the resonant frequency result set is the same as the number of the measured resonant elements, it is determined that the interconnection structure has good connectivity.
The testing method according to claim 36, wherein the preset mode includes:

Confirming the integrity of the interconnect structure by comparing the reference resonant frequency and the measured resonant frequency in the resonant frequency result set Connectivity.
The testing method of claim 38, wherein confirming the connectivity of the interconnection structure by comparing the reference resonant frequency and the measured resonant frequency in the resonant frequency result set includes:

When the reference resonant frequency is equal to the measured resonant frequency or the difference is within a preset range, it is determined that the interconnection structure has good connectivity.
The testing method according to any one of claims 36 to 39, characterized in that the testing method further includes:

When the interconnection structure has good connectivity, the quality factors of the measured resonant element and the reference resonant element are measured and optionally compared.
The testing method according to any one of claims 36 to 40, characterized in that there are multiple resonant elements to be measured, the interconnection structure of each resonant element to be measured is a cylinder, and at least part of the resonant element to be measured is resonant. The components' respective interconnect structures have different diameters;

The test method also includes: a first operation or a second operation;

The first operation includes: when there are at least two measured resonant elements with good connectivity in the corresponding interconnection structure, measuring the quality of the corresponding measured resonant element and the reference resonant element. The measured resonant element has the smallest absolute value of the quality factor difference between the quality factor and the reference resonant element and has good radio frequency performance;

The second operation includes: when there are at least two measured resonant elements with good connectivity in the corresponding interconnection structure, measuring the corresponding measured resonant elements, and optionally determining the quality. The measured resonant element with the largest factor has good radio frequency performance.