CN115267505A - Test method, test structure and application - Google Patents
Test method, test structure and application Download PDFInfo
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- CN115267505A CN115267505A CN202210946893.3A CN202210946893A CN115267505A CN 115267505 A CN115267505 A CN 115267505A CN 202210946893 A CN202210946893 A CN 202210946893A CN 115267505 A CN115267505 A CN 115267505A
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/2851—Testing of integrated circuits [IC]
- G01R31/2884—Testing of integrated circuits [IC] using dedicated test connectors, test elements or test circuits on the IC under test
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Abstract
The application discloses a test method, a test structure and application, and belongs to the field of quantum chip manufacturing. The test structure comprises a first electrical element and a reference resonator element and a resonator element under test coupled thereto, respectively, wherein the resonator element under test is provided with an interconnect structure. By transmitting the probe signal through the first electrical component, a measure of the resonant frequency of the reference resonator element and the measured resonator element can be determined from the corresponding feedback signals. Therefore, the connectivity of the interconnection structure arranged in the tested resonance element can be determined by comparing the measured values of the resonance frequency of the resonance element and the measured value of the resonance frequency of the resonance element.
Description
Technical Field
The application belongs to the field of quantum chip preparation, and particularly relates to a test method, a test structure and application.
Background
The Through Silicon Via (TSV) interconnection technology refers to: a technology for realizing interconnection between different chips or different surfaces of a chip by manufacturing a through hole in a Z-axis direction on a silicon chip and filling a conductive substance in the through hole. Through silicon via interconnection technology can realize three-dimensional interconnection and integration between chips. Which has shorter signal lines and less signal delay and crosstalk and can exhibit higher packaging efficiency at the same planar dimensions.
Thus, as a very potential chip interconnect technology, it is generally desirable to incorporate it into the fabrication process of quantum chips, e.g., superconducting quantum chips of interest herein.
Because the operation and measurement of the superconducting quantum chip need to involve radio frequency signals, when the superconducting quantum chip is interconnected by applying the through silicon via technology, whether the interconnection of the through silicon vias meets the transmission requirement of the radio frequency signals needs to be considered. Therefore, a solution for characterizing the performance, such as the on-off performance, of the tsv interconnection structure in the superconducting quantum chip for transmitting the radio frequency signal is needed.
Disclosure of Invention
In view of this, the present application discloses a testing method, a testing structure, and an application, which can be used to determine the on/off of a through silicon via, thereby facilitating verification of the manufacturing process parameters of the through silicon via, shortening the manufacturing cycle of a chip, and improving the manufacturing quality of the chip.
The scheme exemplified in the present application is implemented as follows.
In a first aspect, the present application proposes a test structure for determining connectivity of a through silicon via interconnect structure.
The test structure includes:
a reference resonant element having a first design resonant frequency;
a measured resonant element having a first element and a second element configured to be connected by an interconnect structure and to be out of plane, the measured resonant element configured based on a design parameter, the design parameter being generated by presetting according to a first design resonant frequency;
a first electrical component independently coupled to the first of the reference resonant element and the resonant element under test, respectively, the first electrical component configured to accept the probing 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.
In the above test structure, the reference resonance element and the resonance element under test have respective resonance frequencies. Also, since the measured resonant element is a design parameter configuration preset based on the resonant frequency of the reference resonant element, the measured resonant element manufactured with high quality will have a resonant frequency corresponding to and matching the design parameter. Thus, the actual resonance frequency of the resonator element under test can be obtained by performing the measurement via the first electrical element. Therefore, when the measured resonant frequency of the tested resonant element is compared with the designed resonant frequency of the tested resonant element, the on-off performance of the interconnection structure can be determined through the comparison result. Wherein the designed resonance frequency is related to or even equal to the resonance frequency of the reference resonator element, i.e. the designed resonance frequency of the resonator element under test (i.e. the second designed resonance frequency) can be inferred by measuring the resonance frequency of the reference resonator element.
Thus, for example, an interconnect structure may be considered to be connected when a measurement of the resonant frequency of the resonant element under test is the same as or close to a certain level to a measurement of the resonant frequency of the reference resonant element. An interconnect structure may be considered open when the measured value of the resonant frequency of the measured resonant element differs or deviates to a certain extent from the measured value of the resonant frequency of the reference resonant element.
In a second aspect, examples of the present application propose a test structure for determining connectivity of a through silicon via interconnect structure, comprising:
the reading bus extends along a first preset direction;
at least one interconnect unit, and each interconnect unit includes n interconnect structures;
at least one resonator which is in one-to-one correspondence with the at least one interconnection unit and is manufactured according to designed resonant frequency parameters is arranged side by side at intervals along a first preset direction, and each resonator extends from a first end to a second end along a second preset direction different from the first preset direction;
each resonator is interrupted by the interconnection structure in the corresponding interconnection unit to form m sub-elements, and the m sub-elements are sequentially connected through the interconnection structure in the interconnection unit;
where m = n +1,n is an integer greater than or equal to 1, the resonator is coupled to the read bus through a sub-element at the first end.
In a third aspect of the present invention, examples of the present application present the application of the aforementioned test structure in being used to implement a test method to determine connectivity of a through silicon via interconnect structure.
In a fourth aspect, examples of the present application propose a test method for determining connectivity of a through-silicon via interconnect structure, the test method comprising:
obtaining a test structure, wherein the test structure is provided with a first electrical element, a reference electrical element and an electrical element to be tested, and the first electrical element is respectively coupled with the reference electrical element and the electrical element to be tested; the electrical element to be tested is manufactured on the basis of a reference electrical element interrupted by an interconnection structure, and is provided with a near-end element and a far-end element which are connected through the interconnection structure and are different in surface, and the electrical element to be tested is coupled with the first electrical element through the near-end element;
transmitting microwave detection signals to the reference electrical element and the electrical element to be detected through the first electrical element;
calculating a reference resonance frequency of the reference electrical component and a measured resonance frequency of the electrical component to be measured from the feedback signal obtained from the first electrical component to form a resonance frequency result set;
and confirming the connectivity of the interconnection structure according to the preset mode according to the resonance frequency result set.
Has the advantages that:
compared with the prior art, in order to measure the quality of the interconnection structure, such as the switching performance, the test structure in the example of the application is simultaneously provided with the reference resonant element and the tested resonant element which is constructed by connecting the components of the test structure through the interconnection structure. And, the first electrical components are simultaneously arranged on the basis of this. Thus, when the test method is implemented, the resonant frequencies of the reference resonant element and the tested resonant element can be measured by the first electrical element, and the connectivity of the aforementioned interconnection structure can be deduced and confirmed from the measurement result.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the prior art of the present application, the drawings used in the description of the embodiments or the prior art will be briefly described below.
Fig. 1 is a schematic structural diagram of a test structure provided in an embodiment of the present application in a top view direction;
FIG. 2 discloses a schematic view of a partial cross-sectional structure of the test structure of FIG. 1 in an axial direction;
FIG. 3 is a schematic diagram of another exemplary test structure in a top view according to an embodiment of the present disclosure;
fig. 4 shows schematic structural diagrams of two other test structures in the top view in the embodiment of the present application.
Fig. 5 discloses a schematic step diagram of a testing method in an embodiment of the present application.
Icon: 101-a substrate; 102-an interconnect structure; 103-a first element; 104-a second element; 201-a reference resonant element; 202-measured resonant element; 202 a-measured resonant element; 203-a first circuit element; 204-second circuit element.
Detailed Description
As mentioned above, the participation of radio frequency signals is often required in superconducting quantum chips in order to manipulate and read them. Therefore, stable transmission of the rf signal is very important. On the other hand, in order to improve the integration level and the like, the three-dimensional layout and packaging of various circuits and components can be performed in the superconducting quantum chip by using the through silicon via interconnection technology. Therefore, when the lines or components laid out in three dimensions need to be associated with rf signals, it is necessary to ensure that the connectivity of the interconnection structure of the through silicon vias is good (e.g., on/off, quality in the case of connection, etc.). However, how to confirm this is a difficulty.
To the best of the inventor's knowledge, the on-off of the interconnect structure is currently determined mainly by detecting and characterizing the dc characteristics of the interconnect structure. For example, a determination is made by measuring resistance-an interconnect connection indicates an open circuit, and an interconnect short circuit indicates a good connection. However, this may not or may not always be effectively equivalent to the performance of the interconnect structure on radio frequency signals. In other attempts, radio frequency performance characterization is aided by measurements of insertion loss, reflection, etc. However, some current superconducting quantum chips require a very low temperature, such as 10mK, to operate properly. Under the temperature, the front stage and the rear stage of the chip can be connected with various radio frequency devices, and TiN attached to the TSV interconnection structure enters a super-conducting state, so that the insertion loss and the reflection of the TiN are extremely small, and the characterization difficulty is high.
In view of the above, in distinction from the above-described attempts, in the examples of the present application, the inventors propose a test structure and a test method that can be implemented by the test structure. The method can be used for judging the connectivity of the through silicon via interconnection structure, so that the manufacturing quality of the superconducting quantum chip can be improved, the manufacturing period of the superconducting quantum chip can be shortened, and the manufacturing efficiency can be improved. It is understood that, based on the solution exemplified in the present application, in some other fields or other types of quantum chips, the same may be applicable to scenarios with the need for connectivity of the through-silicon-via interconnect structure in relation to the performance of radio frequency signals.
In general, the scheme of the present example mainly determines the connectivity of the through silicon via interconnection structure by measuring the resonant frequency and according to the measurement result. Therefore, the reference device and the device to be tested are selected and configured integrally, wherein the device to be tested is provided with the interconnection structure, and the interconnection structure is not configured on the corresponding reference device. And, the reference device and the device under test are designed to have the same, or close or expected deviation, resonant frequency, e.g., 50MHz out of phase.
Therefore, the reference device and the device under test are fabricated based on the resonant frequencies of these designs. Then, in theory, when the fabrication 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 in the manner of the design described above-e.g., the same or close or expected deviations.
When problems occur in the manufacturing process of the interconnect structure, the quality of the interconnect structure deteriorates, and thus the connectivity thereof also deteriorates. Meanwhile, the reference device is not provided with an interconnection structure, so that the reference device cannot be influenced by the problems in the manufacturing process. Then the resonant frequency of the device under test will be discernibly different from the resonant frequency of the reference device. By identifying this difference, it can be determined that the interconnect structure has experienced a quality problem, i.e., poor connectivity.
Based on such recognition, the inventors propose in an example such a test method that can be implemented to determine connectivity of a through-silicon via interconnect structure.
Please refer to fig. 1 and fig. 2. The test structure comprises a first circuit element 203 (or first electrical element), and a reference resonator element 201 and a resonator element under test 202, which are coupled to the first circuit element 203, respectively.
Fig. 1 is a schematic top view of a test structure configured on a substrate 101 in an example of the present application; wherein, for convenience of description and illustration, the first element 103 and the second element 104 included in the tested resonant element 202 are respectively expressed in a visible manner, but as can be seen in connection with fig. 2, the first element 103 and the second element 104 are respectively located on both surfaces (front and back) of the substrate 101; i.e. the elements are selectively located on the front or back side of one chip. Thus, in the front plan view shown in fig. 1, in the actual element, the first element 103 is visible on the front side, while the second element 104 is not visible on the back side.
Fig. 2 is a schematic partial cross-sectional structure diagram in fig. 1, which mainly discloses the distribution of the interconnect structure 102 in the substrate 101 and the matching relationship between the two ends thereof and the first element 103 and the second element 104, respectively. In the field of superconducting quantum chips, the interconnect structure 102 is typically selected to be a superconducting material, and is fabricated by forming a hole (e.g., etching) in a substrate, and then plating a thin film of the superconducting material on the inner wall. In the structure shown in fig. 2, interconnect structure 102 is shown as a generally hollow cylindrical structure. In other examples, the structure may be a solid cylinder under conditions where the process is feasible. As can be seen from fig. 1 and 2, the first circuit element 203 is disposed coplanar with the reference resonator element 201; the first element 103 of the resonant element 202 being tested is coplanar with the first electrical element and the second element 104 is coplanar with the first electrical element. In fig. 2, the first and second elements are each provided with holes corresponding to the interconnect structure 102; the dimensions of the apertures and the relative sizes of the two elements shown therein are merely schematic representations and are not intended to be limiting.
Wherein 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 by simulation calculation through electromagnetic simulation software, so that corresponding structural design parameters can also be obtained. Under ideal conditions, when both resonant elements are produced as expected and with high quality, then the measurement of the resonant frequency of the reference resonant element 201 is typically close to, or even equal to, the first design resonant frequency; likewise, the measured value of the resonant frequency of the measured resonant element 202 is also typically close to, or even equal to, the second design resonant frequency. Also, by proper design, the first design resonant frequency and the second design resonant frequency may be made equal, or the difference between the two may be within a given range.
In the implementation of the test method, the first circuit element 203 is capable of receiving the probe signal and determining, by the aforementioned response results of the two resonance elements coupled thereto, a measured value (first measured value) of the resonance frequency of the reference resonance element 201 and a measured value (second measured value) of the resonance frequency of the resonance element under test 202 by a signal processing and calculation or the like in a conventional manner. Such a measurement may be implemented, for example, based on a matched coupling structure between a read bus and a read resonator in a superconducting quantum chip. Thus, the first circuit element 203 may be a read bus and the reference resonator element 201 and the measured resonator element 202 may be their corresponding read resonators.
As a solution for verifying the through-silicon-via interconnect structure 102, the resonant element 202 under test is configured with the interconnect structure 102. That is, the reference resonator element 201 if it is a continuously arranged resonator structure such as a coplanar waveguide; the resonant element 202 under test may then correspond to a coplanar waveguide interrupted by the through-silicon via interconnect structure 102.
Thus, the resonant element 202 under test may have a first element 103 and a second element 104; with the interconnect structure 102 as a demarcation point, a first element 103 is on the side adjacent to the first electrical element and a second element 104 is on the side away from the first electrical element. Here, a resonant element under test is exemplified by configuring an interconnection structure; it will be appreciated that when one resonator element under test is provided with at least two interconnect structures, then the one resonator element under test may have at least three elements; such as a first element, a second element, a third element, a fourth element, etc., and so on.
The first element 103 and the second element 104 are disposed in an out-of-plane manner in consideration of the existence of the through-silicon via interconnection structure 102. Thus in some examples the test structure is arranged to the substrate 101 and may be exemplified as described before such that the first electrical element is located at the front side of the substrate 101, the reference resonator element 201 is located at the front side of the substrate 101, the first element 103 of the resonator element 202 under test is located at the front side of the substrate 101, the second element 104 of the resonator element 202 under test is located at the back side of the substrate 101, and the interconnect structure 102 located within the substrate 101 extends from the front side of the substrate 101 to the back side of the substrate 101 and is connected at both ends to the first element 103 and the second element 104, respectively.
In view of the manufacturing process, material, and the like, there may be a difference between the designed resonant frequency of the resonant element and the measured value of the resonant frequency measured after the resonant element is actually manufactured, and the measured resonant element 202 configured in the present example is designed and manufactured based on the reference resonant element 201. That is, the measured resonant element 202 is fabricated based on design parameters that are preset to be generated according to the first design resonant frequency of the reference resonant element 201. Such as the materials selected in the fabrication process, the environmental and process conditions, the structural parameters, etc. Based on this, the measured values of the resonance frequencies of the measured resonance element 202 and the reference resonance element 201, which are made with high quality, are close to or identical or meet an expected deviation.
In the example of the present application, the number of resonance elements 202 to be tested can be freely selected. When a plurality of measured resonant elements 202 exist, the measured resonant elements 202 can adopt the same structural design, so that the problem of low accuracy or unrepeatability of results in some cases caused by deviation of measurement results when a single or a small number of measured resonant elements 202 exist can be avoided. Further, the number of interconnect structures in different tested resonator elements 202 and the positions of the interconnect structures (which may be measured by the distance from the first circuit element 203) may also be selected as desired, e.g. all the same or all the different, or some the same, some different, etc.
In order to study the effect of disposing the interconnection structure 102 at different positions in the tested resonant elements 202, the tested resonant elements 202 can be classified into multiple groups according to the position of the interconnection structure 102, each group contains at least one tested resonant element 202, and the positions of the interconnection structures 102 of the tested resonant elements 202 in the same group are the same. In some such examples, the first element 103 of each tested resonant element 202 has a first parameter and the second element 104 has a second parameter. Based on this, the resonance frequency of the resonance element 202 under test is determined jointly by the first parameter and the second parameter. The first and second parameters are, for example, their lengths, and thus together constitute the length of the resonant element 202 under test. The first parameter may be configured to be different for different groups or classes of resonant elements 202 under test.
For example, in the test structure shown in fig. 3, two types (one for each type and two for each type) of the resonant elements 202 under test are included, wherein the interconnect structure 102 of one resonant element 202 under test is close to the first circuit element 203, and the interconnect structure 102 of the other resonant element 202a under test is far from the first circuit element 203. And the length of the first element 103 of the resonant element 202 under test is less than the length of the first element 103 of the resonant element 202a under test, and correspondingly the length of the second element 104 of the resonant element 202 under test is greater than the length of the second element 104 of the resonant element 202a under test.
Further, the second circuit element 204 may also be configured in some examples, based on the needs of some measurements. Like the first circuit element 203, it is also independently coupled to the second element 104 of the reference resonator element 201 and the resonator element 202 under test, respectively. Therefore, both 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 resonant element 202 under test (not labeled in fig. 4) are also coupled to the first and second circuit elements 204, respectively. The second circuit element 204 may have the same structure as the first electrical element, but functionally it may also be used to measure the resonance frequency of the reference resonator element 201 and the measured resonator element 202, obtaining corresponding measurement values. For example, as shown in diagram a in fig. 4.
Furthermore, on the basis of diagram a, more than one interconnect structure 102 may be disposed on the tested resonant element 202, for example, two interconnect structures 102 are disposed on each tested resonant element 202 in diagram B in fig. 4. Also, therefore, the resonant element 202 under test includes a first stage element, a second stage element, and a third stage element connected in series (in series) by two interconnect structures 102. Wherein the first stage element is coupled to the first electrical component and the third stage element is coupled to the second circuit element 204. Note that, since the interconnect structure 102 is a structure that penetrates the substrate 101 and extends to both surfaces of the substrate 101. Thus, the first stage element and the third stage element may be coplanar (and also coplanar with the first circuit element 203 and the second circuit element 204) and respectively coplanar with the second stage element (and also coplanar with the first circuit element 203 and the second circuit element 204).
According to the structure shown in diagram a in fig. 4, an additional one of the interconnect structures 102 shown in diagram B in fig. 4 is arranged to one of the first element 103 and the second element 104 which is longer in length, taking into account the arrangement of one of the interconnect structures 102 and its position of the resonant element 202 to be measured, so that the first-stage element and the second-stage element may be generated by the original first element 103 being interrupted by the additional one of the interconnect structures 102. Then, at this time, the corresponding third stage element is the original second element 104. Similarly, the first stage element is the original first element 103, and the second stage element and the third stage element are generated by the interruption of the original second element 104 by the newly added interconnect structure 102.
As mentioned before, the test structure may be configured as a read bus and at least one read resonator coupled to each other based on an application example of the superconducting quantum chip. Wherein the read bus extends substantially in a first/horizontal direction, each read resonator extends substantially in a second/vertical direction, and all read resonators may be spaced apart along the horizontal direction, as illustrated in fig. 4.
Accordingly, one interconnect element is provided for each read resonator, and each interconnect element has a positive integer number (n) of interconnect structures 102. In other words, in such an example, each read resonator is interrupted by the interconnect structures 102 in its corresponding interconnect cell to form one (m, and m = n + 1) more subelements than the number of respective interconnect structures 102. In this example, by reading the theoretical resonant frequency and the actual resonant frequency measurement value of the resonator, it is also possible to try to determine whether the interconnect structure configured therewith is on or off.
Due to the stability of the manufacturing process and the deviations of the theoretical design from the actual process, it would be beneficial to configure a resonator without the interconnect structure 102 as the reference resonator/reference resonator element 201, and as described above. The reference resonator may have substantially the same structure and arrangement as the resonator with interconnect structure 102. Furthermore, two read buses can also optionally be provided in the test structure, which can be coupled to the subelements of the resonator at the first end and the subelements at the second end, respectively. The two can independently measure the resonant frequency from the two ends of the resonator.
In the above structure, for the measurement of the resonant frequency, a person skilled in the art may adopt a technical means of a microwave resonator in the related field to perform the measurement, and for avoiding repeated description, the measurement may be briefly described as follows: λ = v/f;
where v is the wave velocity, f is the frequency, μ is the magnetic permeability, and ε is the dielectric constant. Then the frequency is calculated in the manner of
Thus, after the substrate has been determined, mu and epsilon are constant, and it can be calculated that the frequency f of the resonator is related to the length of the resonator. Then for the test structure of fig. 1, if the interconnect structure 102 is disconnected, only the reference resonant element 201 can be testedWhereas the resonant frequency of the resonant element 202 under test is not measured due to the fact that the length of the resonant cavity (first element 103) is too short to measure a significant value, the second element 104 is disconnected by the interconnect structure and thus is not coupled to the first circuit element 203. I.e. a resonance frequency can be measured which belongs to the reference resonator element. If the interconnect structure 102 is not disconnected/fully connected, two resonant frequencies can be measured by measuring the resonant frequencies of the reference resonant element 201 and the measured resonant element 202.
Similarly, in the test configuration shown in fig. 3, if the interconnect structure 102 is completely disconnected, only the resonant frequencies of the reference resonant element 201 and the resonant element 202a under test (mainly contributed by its first element 103, whereas its second element 104 cannot be measured because the interconnect structure 102 is disconnected), i.e. two resonant frequencies, can be measured. The resonant frequency of the resonant element 202 to be measured cannot be measured because the length of the resonant cavity (the first element 103) is too short. If the interconnect structure 102 is not disconnected/fully connected, three resonant frequencies can be measured by measuring the resonant frequencies of the reference resonant element 201 and the two resonant elements 202 under test.
In conjunction with the test structure described above, a test method for determining connectivity of the through silicon via interconnect structure 102 may be implemented. Moreover, the connectivity can be used to verify the design process and parameters of the tsv interconnect structure 102 in the chip so as to obtain a better manufacturing process and design parameters of the tsv interconnect structure 102, and further obtain a high-quality tsv interconnect structure 102.
Further, according to the described test structure, the connectivity of the through-silicon-via interconnection structure 102 determined by the test method can also reflect the performance of the through-silicon-via interconnection structure in the transmission of radio frequency signals well, and therefore, the through-silicon-via interconnection structure has great potential and value in the manufacturing of superconducting quantum chips.
In general, as shown in fig. 5, the testing method mainly includes the following steps:
and S101, obtaining a test structure.
The test structure may be fabricated with reference to the foregoing disclosure. Typically the test structure may comprise a first electrical component, a reference electrical component and an electrical component to be tested. Wherein the electrical component to be tested is fabricated based on the reference electrical component interrupted by the interconnect structure 102. In other words, the electrical component under test may have the same or similar design structure parameters, materials, and process conditions as the reference electrical component, except for the interconnect structure 102.
The electrical component to be tested can be manufactured as follows:
a length of corresponding material-which may be described as proximal and distal elements disposed out-of-plane-is fabricated on each of the top and bottom surfaces of the substrate/substrate 101. Wherein the proximal element is proximal to the first electrical element and the distal element is distal to the first electrical element. The substrate is perforated along the thickness, and the holes are filled with corresponding materials (such as conductor materials, etc.), and the two ends of the substrate are respectively in electrical contact and connection with the corresponding material. In integrated circuit related processes, the fabrication of the tsv interconnect structure 102 generally includes the operations of via fabrication, via insulation, barrier layer, seed layer, and fill plating.
Thereby, the first electrical component is coupled to the reference electrical component and the electrical component to be tested is coupled to the first electrical component via the aforementioned proximal element.
And S102, measuring the resonant frequency by using the microwave detection signal.
According to the construction mode of the test structure, microwave detection signals can be selectively transmitted to the reference electrical element and the electrical element to be tested through the first electrical element. Wherein the first electrical component can be used for transmitting microwave signals by optionally being a transmission line such as a coplanar waveguide. In superconducting quantum chips, it can be described as a read Line (e.g., readout Line). The reference electrical component and the electrical component to be tested may be Resonator elements (e.g., readout Resonator) coupled to the first electrical component, and may also be fabricated using coplanar waveguides. In general, the quality factor is calculated by the ratio of the resonance frequency and the bandwidth. For example, for the example of the superconducting quantum chip, the measuring the resonant frequency of the resonant element by using the first electrical element may be to obtain corresponding data by performing a test using a vector network analyzer, and then obtain a corresponding Q value by data fitting; and are not described in detail herein.
And S103, obtaining data from the feedback signal and confirming the connectivity of the interconnection structure 102 according to the data.
Due to the coupling relation between the first electrical element and the reference electrical element and the electrical element to be measured, the microwave signal input by the first electrical element can act on the two reference electrical elements and the electrical element to be measured, and then the signal can be fed back to the first electrical element. Further, connectivity of the interconnect structure 102 may be confirmed according to a predetermined pattern based on the resulting set of resonant frequencies.
Since the resonance frequency combination set comprises a measurement value of the resonance frequency of the reference electrical component and a measurement value of the resonance frequency of the electrical component to be tested. Thus, based on the different utilization-preset patterns-of these measurements, the connectivity of the interconnect structure 102 can be confirmed.
For example, since the reference electrical element is not fabricated through the through-silicon via interconnect structure 102, it can be theoretically always measured to the resonance frequency. Since the tested electrical component involves the fabrication of the through-silicon via interconnect structure 102, the quality of the interconnect structure 102 may relate to whether its corresponding resonant frequency can be measured. When the connectivity of each interconnect structure 102 is good, then the number of measured components and measured resonant frequencies should be the same. Then, when the number of measured resonant frequencies in the result set of resonant frequencies is used as the basis, the interconnection structure 102 is determined to have good connectivity when the number of measured resonant frequencies in the result set of resonant frequencies is the same as the number of electrical components to be tested. Conversely, if the numbers are different, it may be determined that there are instances where connectivity of one or more interconnect structures 102 is poor.
Further, as described above, the magnitude of the resonant frequency is related to the length of the resonator. And when the resonant element is fabricated with the through-silicon via interconnect structure 102 and coupled to the first electrical component, the lack of connectivity of the interconnect structure 102 theoretically corresponds to a measured resonant frequency of a portion in close proximity to the first electrical component (e.g., the aforementioned proximal component, such as the first component 103 of fig. 1). Therefore, when the length of the proximal member is short, the measured resonance frequency may be very high, and thus it may be considered that the resonance frequency is not measured in practical applications.
Further, when the length of the part of the resonant element 202 under test close to the first electrical element (the proximal element) is relatively longer and the length of the part far from the first electrical element (the distal element, e.g. the second element 104 in fig. 1) is shorter, the resonant frequency of the proximal element therein can be measured in case of poor connectivity of the interconnect structure 102-but a significant and recognizable gap will occur between the measured value of the resonant frequency of the electrical element under test in case of good connectivity of the interconnect structure 102. Therefore, based on this, the aforementioned preset mode may further include: the connectivity of the interconnect structure 102 is confirmed by comparing the reference resonant frequency to the measured resonant frequency in the resulting set of resonant frequencies. Wherein the reference resonant frequency may reflect a measure of the resonant frequency of the electrical component under test with good connectivity of the interconnect structure 102; this is because the electrical component to be measured is manufactured according to the design parameters determined by the design of the reference electrical component. And it is understood that, in this case, when the reference resonance frequency is equal to the measured resonance frequency or the difference is within a preset range, it can be determined that the connectivity of the interconnect structure 102 is good.
Furthermore, the interconnect structure 102 and the resonator element based thereon, as well as the coupling structure to the first electrical element, are important performance index parameters of interest, for example, in applications such as superconducting quantum chips, such as Quality Factor (Q-value, Q-Factor). The method for calculating the quality factor may adopt the existing technology in the field, and the present application is not limited to this specifically. For example, the Q value is calculated by a frequency method, i.e., in the frequency domain, such as a frequency conversion method or the like.
Therefore, the above connectivity to the tsv interconnect structure 102 may also include evaluating quality factors of components based thereon; and, the higher the quality factor, i.e., Q value, the better the connectivity of interconnect structure 102. Accordingly, after confirming that the connectivity of the interconnect structure 102 satisfies the requirements through the result set of resonant frequencies, the quality factor may be further measured. That is, in some examples, the testing method may further include: when the interconnection structure 102 has good connectivity, the quality factors of the electrical component to be tested and the reference electrical component are determined, and an optional comparison is performed. By comparison, the element with the best quality factor can be selected from the compared objects, so that the setting position and the structural parameters of the interconnection structure 102 and the tested electrical element with more ideal corresponding manufacturing process can be obtained, and further, a corresponding scheme can be implemented when a chip is actually manufactured.
As a further optimization option, in some examples, the interconnect structure 102 may also be selected for structural adjustment, so as to obtain better manufacturing conditions of the interconnect structure 102 actually used in some cases. For example, taking the interconnect structure 102 as a cylinder as an example, when the interconnect structure 102 is determined to be connected by comparing or counting the number of resonant frequencies in the resonant frequency result set, the diameters of the interconnect structures 102 with different cylinders and the associated quality factors can be further considered.
Accordingly, the test method may further comprise: upon determining that the connectivity of the interconnect structure 102 is good and that there are at least two corresponding electrical components under test as determined by the resonant frequency, then the quality factors of the corresponding electrical components under test and the reference electrical component can be determined. Then, the electrical component to be tested having the smallest absolute value of the difference between the quality factor and the quality factor of the reference electrical component is selected from the determined quality factors as the component having good radio frequency performance.
In the above example, the quality factor of the tested electrical component meeting the requirement is compared with the quality factor of the reference electrical component. In other examples, the quality factors of the tested electrical components that meet the requirements may be scaled. In other words, when the connectivity of the corresponding interconnect structure 102 is determined to be good and there are at least two corresponding electrical components to be tested, the corresponding electrical components to be tested can be tested, and the electrical component to be tested with the largest quality factor can be determined as having good radio frequency performance.
Briefly, in some examples of the present application, the testing of connectivity of the through silicon via interconnect structure 102 may include a determination of whether to connect, and further include a determination of the quality of the connection in the case of a connection. Whether the connection is established or not can be judged by comparing the quantity of the measured value of the measured resonant frequency and the value of the measured value of the reference resonant frequency. The communication quality is mainly determined by comparing the quality factors, and the numerical comparison may further include comparing the quality factors of the elements corresponding to the measured resonant frequency and the reference resonant frequency, or comparing the quality factors of the elements corresponding to the measured resonant frequency.
The embodiments described above with reference to the drawings are exemplary only for the purpose of illustrating the present application and are not to be construed as limiting the present application. In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the foregoing description explains the embodiments of the present application in detail with reference to the drawings. However, it will be appreciated by those of ordinary skill in the art that in the examples of the present application, numerous technical details are set forth in order to provide a better understanding of the present application. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments. The division of the examples is for convenience of description, and should not constitute any limitation to the specific implementation manner of the present application, and the embodiments may be mutually incorporated and referred to each other without contradiction.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.
Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The construction, features and functions of the present application are described in detail in the embodiments illustrated in the drawings, which are only preferred embodiments of the present application, but the present application is not limited by the drawings, and all equivalent embodiments that can be modified or changed according to the idea of the present application are within the scope of the present application without departing from the spirit of the present application.
Claims (18)
1. A test structure for determining connectivity of a through-silicon via interconnect structure, the test structure comprising:
a reference resonant element having a first design resonant frequency;
a measured resonant element having first and second elements configured to be connected and out-of-plane by the interconnect structure, the measured resonant element configured based on design parameters that are pre-established according to the first design resonant frequency;
a first electrical element independently coupled to the first one of the reference resonating element and the measured resonating element, respectively;
the first electrical component is configured to accept a probing 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.
2. The test structure of claim 1, wherein the test structure comprises at least two groups of resonant elements under test, each group comprising at least one resonant element under test, each group being independently configured;
each first element has a first parameter and each second element has a second parameter, the first and second parameters together determining the resonant frequency of the resonant element under test;
the first parameters of the tested resonance elements in the same group are the same, and the first parameters of the tested resonance elements in different groups are different.
3. The test structure of claim 2, wherein the first parameter is a length of the first element and the second parameter is a length of the second element.
4. The test structure according to any one of claims 1 to 3, further comprising a second circuit element independently coupled to the second element of the reference resonator element and the resonator element under test, respectively;
the second circuit element is configured to accept a probe signal to determine a measure of the resonant frequency of the measured resonant element and a measure of the resonant frequency of the reference resonant element.
5. The test structure of claim 4, wherein the resonant element under test comprises a first section of elements, a second section of elements, and a third section of elements connected in sequence by two interconnect structures;
wherein the first stage element is coupled to the first electrical element and the third stage element is coupled to the second circuit element;
wherein the first and second segment elements are provided by a first element and the third segment element is provided by a second element; alternatively, the first stage element is provided by a first element and the second and third stage elements are provided by a second element.
6. The test structure of claim 5, wherein the first stage elements and the third stage elements are in a coplanar configuration.
7. The test structure of claim 4, wherein the reference resonating element is configured coplanar with the first electrical element;
and/or the first element is arranged coplanar with the first electrical element, and the second element is arranged coplanar with the second circuit element;
alternatively, the measured resonant element has a second design resonant frequency, and the first design resonant frequency is equal to the second design resonant frequency or differs from the second design resonant frequency by a given range.
8. A test structure for determining connectivity of a through-silicon via interconnect structure, the test structure comprising:
a read bus extending in a first preset direction;
at least one interconnection unit, wherein each interconnection unit comprises n interconnection structures, and n is an integer greater than or equal to 1; and
at least one resonator arranged side by side and at intervals along the first preset direction, wherein the at least one resonator is in one-to-one correspondence with the at least one interconnection unit;
each resonator is manufactured according to designed resonance frequency parameters, and extends from a first end to a second end along a second preset direction different from the first preset direction;
each resonator is interrupted by the interconnect structure in the corresponding interconnect unit to form m subelements, and m = n +1; wherein the m sub-elements are connected in sequence by an interconnect structure in an interconnect unit, the resonator being coupled to the read bus by a sub-element at the first end.
9. The test structure of claim 8, wherein the read bus and the resonator are each coplanar waveguides;
and/or, in the at least one interconnection unit, the number of interconnection structures in at least two interconnection units is different;
and/or the test structure comprises a reference resonant element with a given resonant frequency, the reference resonant element is arranged along the second preset direction in an extending mode, and the reference resonant element is coupled with the reading bus.
10. The test structure of claim 8, wherein the test structure comprises two read buses, the two read buses being arranged in parallel and spaced apart;
the subelement at the first end and the subelement at the second end of each resonator are coupled to the two read buses, respectively.
11. The test structure of claim 10, characterized in that it comprises a reference resonant element with a given resonant frequency, both ends of which are coupled to the two read buses, respectively.
12. Use of a test structure according to any one of claims 1 to 11 in a method of performing a test to determine connectivity of a through silicon via interconnect structure.
13. A testing method for determining connectivity of a through silicon via interconnect structure, the testing method comprising:
obtaining a test structure having a first electrical element, a reference electrical element, and an electrical element to be tested, the first electrical element being coupled to the reference electrical element; the electrical element to be tested is manufactured on the basis of a reference electrical element interrupted by an interconnection structure, the electrical element to be tested is provided with a near-end element and a far-end element which are connected through the interconnection structure and are different in surface, and the electrical element to be tested is coupled with the first electrical element through the near-end element;
transmitting microwave detection signals to the reference electrical element and the electrical element to be detected through the first electrical element;
calculating a reference resonance frequency of the reference electrical element and a measured resonance frequency of the electrical element to be measured by using the feedback signal obtained by the first electrical element to form a resonance frequency result set;
and confirming the connectivity of the interconnection structure according to a preset mode according to the resonance frequency result set.
14. The test method of claim 13, wherein the preset mode comprises:
and when the number of the measured resonant frequencies in the resonant frequency result set is the same as the number of the electrical elements to be measured, judging that the connectivity of the interconnection structure is good.
15. The test method of claim 13, wherein the preset mode comprises:
and confirming the connectivity of the interconnection structure by comparing the reference resonance frequency in the resonance frequency result set with the measured resonance frequency.
16. The testing method of claim 15, wherein confirming connectivity of the interconnect structure by comparing a reference resonant frequency of the result set of resonant frequencies to the measured resonant frequency comprises:
and when the reference resonant frequency is equal to the measured resonant frequency or the difference value is within a preset range, judging that the connectivity of the interconnection structure is good.
17. The testing method of one of claims 14 to 16, further comprising:
and when the connectivity of the interconnection structure is good, determining and optionally comparing the quality factors of the electrical element to be tested and the reference electrical element.
18. The method according to claim 17, wherein the electrical component under test is a plurality of electrical components, the interconnection structure of each electrical component under test is a cylinder, and the diameters of the respective interconnection structures of at least some of the electrical components under test are different;
the test method further comprises the following steps: a first operation or a second operation;
the first operation includes: when at least two corresponding electrical elements to be tested with good interconnection structure connectivity exist, the quality factors of the corresponding electrical elements to be tested and the reference electrical element are measured, and the electrical elements to be tested with the minimum absolute value of the quality factor difference between the quality factors and the reference electrical element can be optionally judged to have good radio frequency performance;
the second operation includes: and when at least two corresponding electrical elements to be tested with good interconnection structure connectivity exist, the corresponding electrical elements to be tested are tested, and the electrical elements to be tested with the largest quality factor are optionally judged to have good radio frequency performance.
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| CN202210946893.3A CN115267505A (en) | 2022-08-09 | 2022-08-09 | Test method, test structure and application |
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| WO2024032484A1 (en) * | 2022-08-09 | 2024-02-15 | 本源量子计算科技（合肥）股份有限公司 | Test structure for superconducting quantum chip and test method for superconducting quantum chip |
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| WO2024032484A1 (en) * | 2022-08-09 | 2024-02-15 | 本源量子计算科技（合肥）股份有限公司 | Test structure for superconducting quantum chip and test method for superconducting quantum chip |
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