Mutual Connection Structure Impedance Measurement Circuit, Measuring Apparatus, and Measuring Method

Abstract

Provided is an interconnected structure impedance measurement circuit. By optimizing the Wheatstone bridge structure, three parallel branches are adopted. In one of the branches, the interconnected structure to be measured is connected in series, and the two resistors in the other two branches are connected in series. Control is performed such that the branch of the interconnected structure is turned on simultaneously with one of the other two branches, the voltage between the two turned-on branches is measured, and the impedance of the two interconnected structures is calculated based on the current introduced into the interconnected structure impedance measurement circuit, the measured voltage, and the resistance in the branch. The embodiments of the present disclosure can easily and scalably measure the impedance of the interconnected structure, and can accurately monitor in real time the impedance of a single interconnected structure in a reliability experiment. The present disclosure further provides an interconnected structure impedance measurement device and a measurement method.

Description

Technical Field

[0001] [Cross - reference to Related Disclosures] This disclosure claims the priority of a Chinese patent application filed with the National Intellectual Property Administration on June 30, 2022, with the publication number CN202210779103.7 and the invention title "Interconnection Structure Impedance Measurement Circuit, Measurement Device and Measurement Method", and incorporates all the contents of this application by reference into this disclosure.

[0002] [Technical Field] Embodiments of this disclosure relate to the fields of circuit test technology and reliability test technology, but are not limited thereto. Specifically, they relate to an interconnection structure impedance measurement circuit, a measurement device, and a measurement method.

Background Art

[0003] The accurate measurement of micro - resistance impedance is a focus of attention in many industries. In particular, for interconnection metal wires and interconnection pads, the accurate measurement of resistance plays an important role in evaluating the performance of the entire system and the welding quality. Regarding the reliability evaluation of a single interconnection structure, taking the electromigration test as an example, there is still a lack of an effective method for accurately monitoring the resistance of a single welding pad structure in a long - term aging experiment.

[0004] To accurately measure the resistance impedance of many small structures such as interconnected metal wires, researchers have proposed various ideas and methods. Among them, the four-probe method is recognized as an accurate measurement method. However, the four-probe method has several drawbacks in the application process. It cannot measure resistance impedance on a large scale in real time, the measurement is complex, the cost is high, and it is inconvenient because manual measurement is required. The classical Wheatstone bridge structure can also be used for measuring small resistances. However, the Wheatstone bridge structure has many constraints, requires three known resistance impedances, and it is necessary to select appropriate resistance impedances to balance the bridge. Then, the unknown resistance impedance is obtained by solving the equation, which is difficult to meet the needs and the application scenarios are limited. Therefore, there is a need for a device or method that can accurately measure the impedance of the interconnected structure, which is scalable, automated, and easy to implement.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present disclosure provides an interconnected structure impedance measurement circuit, a measurement device, and a measurement method. In a first aspect, an embodiment of the present disclosure includes a first branch path, a second branch path, and a third branch path connected in parallel. The first branch path includes a first interconnected structure, a second interconnected structure, and a first switch connected in series. The second branch path includes a first resistor, a second resistor, and a second switch connected in series. The third branch path includes a third resistor, a fourth resistor, and a third switch connected in series. The impedance of the first interconnected structure and the impedance of the second interconnected structure are determined by a first voltage between the first branch path and the second branch path, the first voltage between the first branch path and the 3A mutual connection structure impedance measurement circuit is provided that identifies based on a second voltage between a branch path, the first resistor, the second resistor, the third resistor, the fourth resistor, and a first current input to the mutual connection structure impedance measurement circuit. The first voltage is detected when the first switch and the second switch are off and the third switch is on. The second voltage is detected when the first switch and the third switch are off and the second switch is on.

[0006] In another aspect, an embodiment of the present disclosure includes a constant current source, a voltage detection module, a control module, and the mutual connection structure impedance measurement circuit described above. The constant current source is connected to the first branch path, the second branch path, and the third branch path, and is configured to supply a first current to the mutual connection structure impedance measurement circuit when the first switch and the second switch are off and the third switch is on, or when the first switch and the third switch are off and the second switch is on. The voltage detection module is connected to the first branch path, the second branch path, and the third branch path respectively, and is configured to detect a first voltage between the first branch path and the second branch path when the first switch and the second switch are off and the third switch is on, and to detect a second voltage between the first branch path and the 3 second branch path when the first switch and the third switch are off and the second switch is on. The control module is configured to control the constant current source to supply the first current to the mutual connection structure impedance measurement circuit, to control the first switch, the second switch, and the third switch to be on or off, to acquire the first voltage and the second voltage detected by the voltage detection module, and to calculate the impedance of the first mutual connection structure and the impedance of the second mutual connection structure based on the first resistor, the second resistor, the third resistor, the fourth resistor, the first voltage, the second voltage, and the first current. A mutual connection structure impedance measurement device is further provided.

[0007] In another aspect, an embodiment of the present disclosure is a method for measuring the impedance of an interconnection structure applied to the above-described interconnection structure impedance measurement device, the method comprising: supplying a first current to the interconnection structure impedance measurement circuit; controlling the interconnection structure impedance measurement circuit to be in a first state to detect a first voltage between the first branch and the second branch, wherein in the first state, the first switch and the second switch are turned off and the third switch is turned on; controlling the interconnection structure impedance measurement circuit to switch from the first state to a second state to detect a second voltage between the first branch and the third branch, wherein in the second state, the first switch and the third switch are turned off and the second switch is turned on; stopping supplying the first current to the interconnection structure impedance measurement circuit, and calculating the impedances of the first interconnection structure and the second interconnection structure based on the first resistor, the second resistor, the third resistor, the fourth resistor, the first voltage, the second voltage, and the first current.

[0008] In another aspect, an embodiment of the present disclosure is a method for measuring the impedance of an interconnection structure applied to the above-described interconnection structure impedance measurement device, the method comprising: measuring the impedance of the second interconnection structure by the above-described method; controlling the interconnection structure impedance measurement circuit to switch from the second state to a third state, wherein in the third state, the first switch is turned off and the second switch and the third switch are turned on; providing a second current to the interconnection structure impedance measurement circuit within a preset period to increase the current stress and accelerate the degradation of the interconnection structure; measuring the impedance of the second interconnection structure by the above-described method, comparing it with a preset invalid impedance value, and ending the measurement when the impedance of the second interconnection structure reaches the invalid impedance value. BRIEF DESCRIPTION OF THE DRAWINGS

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

DETAILED DESCRIPTION OF THE INVENTION

[0010] In the following, exemplary embodiments will be described in more detail with reference to the drawings. However, the aforementioned exemplary embodiments can be embodied in different manners and should not be construed as being limited to the embodiments described in this specification. Rather, the purpose of providing these embodiments is to make the present disclosure detailed and complete, and to enable those skilled in the art to fully understand the scope of the present disclosure.

[0011] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0012] The terms used herein are for illustrative purposes only and are not intended to limit the present disclosure. In this specification, unless the context clearly dictates otherwise, the singular forms "a" and "the" are intended to include the plural forms as well. Also, when using the terms "comprising" and / or "consisting of" in this specification, it indicates the presence of a particular feature, whole, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groups thereof.

[0013] Embodiments of the present invention can be described with reference to plan views and / or cross-sectional views by means of ideal schematic diagrams of the present disclosure. Therefore, the illustrated examples may be modified according to manufacturing techniques and / or tolerances. Thus, the embodiments are not limited to the illustrated embodiments and include modifications based on the configurations formed in the manufacturing process. Therefore, the regions illustrated in the drawings are schematic, and the shapes of the regions shown in the drawings illustrate the specific shapes of the regions of the elements, but do not imply limitations.

[0014] Unless otherwise specifically limited, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art. Also, for terms defined in common dictionaries, it should be understood that they have the same meaning as in the context of the relevant technology and the present disclosure, and should not be construed as having an idealized meaning or an overly formal meaning unless clearly so limited herein.

[0015] In addition to the fact that the structures of the interconnecting metal wires and interconnecting pads are both minute, due to their good metallic conductivity, accurately measuring the resistance value has always been a pain point in the industry. In reliability experiments, the interconnecting structure is also an important object of attention in the experiment. In long-term temperature / current stress, the degree of deterioration or the presence or absence of failures in the interconnecting structure is often determined by changes in the resistance value of the interconnecting structure. Since the resistance of the interconnecting structure itself is minute and the changes occurring therein are extremely minute, accurately monitoring the impedance of the interconnecting structure in real time is very important for reliability experiments. The four-probe method for accurately measuring the interconnecting wires and welding pads can be said to have the highest accuracy, but the measurement process is complex, the resistance value cannot be monitored in real time, and the cost is high. The classical Wheatstone bridge can accurately measure the resistance value, requires three known resistance values, has limited practical levels, and is difficult to apply to large-scale applications.

[0016] To solve the above problems, embodiments of the present disclosure provide an interconnecting structure impedance measurement circuit. As shown in FIG. 1, the interconnecting structure impedance measurement circuit includes a first branch path, a second branch path, and a third branch path connected in parallel. The first branch path includes a first interconnecting structure, a second interconnecting structure, and a first switch K1 connected in series. The second branch path includes a first resistor R1, a second resistor R2, and a second switch K2 connected in series. The third branch path includes a third resistor R1', a fourth resistor R2', and a third switch K3 connected in series.

[0017] The impedance R3 of the first interconnecting structure and the impedance R4 of the second interconnecting structure are determined based on a first voltage Vg between the first branch path and the second branch path, a second voltage Vg' between the first branch path and the third branch path, the first resistor R1, the second resistor R2, the third resistor R1', the fourth resistor R2', and a first current I input to the interconnecting structure impedance measurement circuit.

[0018] Here, the first voltage Vg is detected when the first switch K1 and the second switch K2 are off and the third switch K3 is on, and the second voltage Vg’ is detected when the first switch K1 and the third switch K3 are off and the second switch K2 is on.

[0019] The mutual connection structure impedance measurement circuit according to an embodiment of the present disclosure optimizes the Wheatstone bridge structure, adopts three branch paths connected in parallel, in one of which the mutual connection structure to be measured is connected in series, and two resistors in the other two branch paths are connected in series. By controlling such that the branch path of the mutual connection structure is turned on simultaneously with one of the other two branch paths respectively, the voltage between the two turned-on branch paths is measured, and based on the current introduced into the mutual connection structure impedance measurement circuit, the measured voltage, and the resistors in the branch paths, the impedances of the two mutual connection structures are calculated. The embodiment of the present disclosure can easily, on a large scale, and accurately measure the impedance of the mutual connection structure, and can accurately monitor in real time the impedance of a single mutual connection structure in a reliability experiment.

[0020] FIG. 2 is a schematic diagram of the physical structure corresponding to the mutual connection structure impedance measurement circuit shown in FIG. 1. As shown in FIG. 2, the first mutual connection structure and the second mutual connection structure are respectively connected to a PCB (Printed Circuit Board) and an integrated circuit chip substrate (IC Substrate), and may be connected, for example, by BGA balls (Ball Grid Array Package Balls).

[0021] FIG. 3 is a circuit diagram of a traditional Wheatstone bridge test resistor. As shown in FIG. 3, the resistance values of R1, R2, and R3 are known, and R4 is the resistor to be measured. G is a galvanometer. When the galvanometer needle points to zero, the bridge reaches equilibrium, and the resistance value of R4 can be calculated by R1*R4 = R2*R3.

[0022] 1 and 2, R3 is the impedance of the first interconnect structure, R4 is the impedance of the second interconnect structure, R1 and R2 are known resistances, and R1' and R2' are known resistances. I is the input current, Vg is the voltage difference between node 3 and node 4, and Vg' is the voltage difference between node 3 and node 4'. Through multiple iterations, a set of nonlinear equations can be formulated to calculate the values ​​of the impedance R3 of the first interconnect structure and the impedance R4 of the second interconnect structure.

[0023] Kirchhoff's law gives us the following equation:

[0024]

number

[0025] where R is the resistance of the second branch and R' is the resistance of the third branch. By solving the above equations (1), (2), (3), and (4) simultaneously, the following equation is obtained.

[0026]

number

[0027] The requirements for the resistance values ​​of the four resistors R1, R2, R1', and R2' are not very high. However, when measuring the impedance of a microstructure, the measurement accuracy can be improved by making R1 / R2 ≒ R1' / R2'.

[0028] In some embodiments, the resistance value of the first resistor R1 is not equal to the resistance value of the third resistor R1', and the resistance value of the second resistor R2 is not equal to the resistance value of the fourth resistor R2'.

[0029] Embodiments of the present disclosure can be applied to multiple technical fields such as electronic packages, reliability tests, and precision measurements. In the manufacturing process of electronic packages, welding interconnections are often used. The quality of the interconnection structure directly affects the quality of the product, and the importance of quickly evaluating the welding quality of the interconnection structure is self-evident. Poor welding is reflected by an increase in resistance. The impedance of the interconnection structure can be quickly detected using the interconnection structure impedance measurement circuit of the embodiments of the present disclosure, and it can be used as a detection tool for monitoring changes in the production process in real time. Similarly, throughout the chip manufacturing process, since the interconnection structure has contact resistance, its resistance value is often difficult to determine. By using the interconnection structure impedance measurement circuit of the embodiments of the present disclosure, the impedance of the micro interconnection structure can be quickly and accurately measured, and it has important application value in aspects such as evaluating the performance of the entire system.

[0030] In reliability tests, it is often required to continuously monitor changes in impedance values. Therefore, the interconnection structure impedance measurement circuit of the embodiments of the present disclosure can be improved to realize the monitoring of the impedance of a single interconnection structure in a reliability experiment.

[0031] In some embodiments, the unit of the impedance R3 of the first interconnection structure is milliohm. That is, the first interconnection structure in the interconnection structure impedance measurement circuit is used as an interconnection structure with a small impedance, and a single connection structure including a second interconnection structure is formed in the first branch.

[0032] The first interconnection structure with a small impedance may have multiple mounting forms. Exemplarily, the first interconnection structure may be at least two fifth resistors connected in parallel, the resistance value of each fifth resistor is the same, and the resistance value of the fifth resistor is equal to the resistance value of the second interconnection structure, or the first interconnection structure may be realized by a wire.

[0033] In an embodiment of the present disclosure, as shown in FIGS. 4 and 5, the first interconnection structure is three fifth resistors R5 connected in parallel. Actually, the number of fifth resistors R5 connected in parallel continues to increase. The more the number of fifth resistors R5, the more accurate the measurement of the impedance of a single interconnection structure (i.e., the impedance R4 of the second interconnection structure). Note that the impedance R3 of the first interconnection structure is the impedance of each fifth resistor connected in parallel.

[0034] In some embodiments, when the first interconnection structure is n fifth resistors R5 connected in parallel (n is an integer greater than or equal to 2), the resistance value of the second resistor R2 is n times the resistance value of the first resistor R1, and the resistance value of the fourth resistor R2' is n times the resistance value of the third resistor R1'. That is, the selection of the resistance values of the first resistor R1, the second resistor R2, the third resistor R1', and the fourth resistor R2' in the second branch and the third branch is related to the number of fifth resistors R5 connected in parallel in the first interconnection structure. As shown in FIG. 4, after three fifth resistors R5 are connected in parallel, they are connected in series with another single connection structure (i.e., the second interconnection structure R4). The impedance R4 of the second interconnection structure is about three times the impedance of the three fifth resistors R5.

[0035] FIGS. 6 and 7 are two scenarios where the interconnection structure impedance measurement circuit is applied. For different measurement needs, the two measurement design schemes in FIGS. 6 and 7 can be adopted.

[0036] As shown in FIG. 6, the interconnection structure impedance measurement circuit is packaged in an interconnection structure impedance measurement device. The PCB is connected to the interconnection structure impedance measurement device via the first interconnection structure and the second interconnection structure, and the impedance of the above two interconnection structures is measured using the interconnection structure impedance measurement device. In the scenario shown in FIG. 6, the design of the PCB layout is relatively simple and the layout is also saved, but the requirements for the interconnection structure impedance measurement device are high.

[0037] As shown in FIG. 7, when the interconnect structure impedance measurement circuit is integrated on a PCB substrate and measuring the impedance R3 of the first interconnect structure and the impedance R4 of the second interconnect structure, the interconnect structure impedance measurement device only needs to supply current. In the scenario shown in FIG. 7, the construction of the measurement system is simple and the measurement is convenient. However, the difficulty of PCB layout design increases, the layout consumption increases, and the cost becomes high.

[0038] Embodiments of the present disclosure further provide an interconnect structure impedance measurement device, which includes a constant current source (A), a voltage detection module (V), a control module, and an interconnect structure impedance measurement circuit as shown in FIG. 8. The interconnect structure impedance measurement circuit is the interconnect structure impedance measurement circuit shown in FIG. 1.

[0039] The constant current source is connected to the first branch, the second branch, and the third branch. When the first switch K1 and the second switch K2 are off and the third switch K3 is on, or when the first switch K1 and the third switch K3 are off and the second switch K2 is on, a first current is supplied to the interconnect structure impedance measurement circuit.

[0040] The voltage detection module is respectively connected to the first branch, the second branch, and the third branch. When the first switch K1 and the second switch K2 are off and the third switch K3 is on, the first voltage Vg between the first branch and the second branch is detected. And when the first switch K1 and the third switch K3 are off and the second switch K2 is on, the second voltage Vg' between the first branch and the 3 second branch is detected.

[0041] The control module controls a constant current source to supply a first current to the interconnection structure impedance measurement circuit, controls the on or off of the first switch K1, the second switch K2, and the third switch K3, obtains the first voltage Vg and the second voltage Vg' detected by the voltage detection module, and based on the first resistor R1, the second resistor R2, the third resistor R1', the fourth resistor R2', the first voltage Vg, the second voltage Vg', and the first current, calculates the impedance R3 of the first interconnection structure and the impedance R4 of the second connection structure.

[0042] The interconnection structure impedance measurement device includes a constant current source, two voltmeters, three switches, two interconnection structures, and four resistors. The two interconnection structures are the resistors to be measured (R3, R4), and the resistance values (R1, R2, R1', R2') of the four resistors are known. In a total of three parallel branches, the first branch includes one first switch K1, the first interconnection structure, and the second interconnection structure. The second branch includes one second switch K2 and two fixed resistors R1 and R2. The third branch includes one third switch K3 and two fixed resistors R1' and R2'. The voltmeter V connects the first strip and the second strip, and connects the first strip and the third strip. When measuring the impedances R3 and R4 of the interconnection structure, connect the first current supplied by the constant current source, obtain the first voltage Vg and the second voltage Vg' through measurement, and substitute them into the above formulas (5) and (6) to simultaneously obtain the impedance R3 of the first interconnection structure and the impedance R4 of the second interconnection structure. By controlling the on and off of the switches (K1, K2, K3) by the control module, real-time monitoring of the impedances of the impedance R3 of the first interconnection structure and the impedance R4 of the second interconnection structure is realized.

[0043] The realization principle of real-time monitoring of the impedance of the interconnection structure can also be applied to the accurate measurement of the resistance impedance of the micro-structure. The measurement of the resistance impedance of the micro-structure usually does not require real-time switching of the control module. The structure of its core circuit is almost the same. Both measure Vg and Vg', substitute them into formulas (5) and (6) to obtain R3 and R4, directly measure the resistance impedance, measure the voltage, and obtain the resistance according to the formula to improve its accuracy. Here, by selecting the resistance values of the four resistors R1, R2, R1' and R2', R1 / R2≈R1' / R2' can be achieved, and the measurement accuracy can be further improved.

[0044] In some embodiments, as shown in FIG. 9, when the interconnection structure impedance measurement circuit is the interconnection structure impedance measurement circuit as shown in FIG. 4, the constant current source is further configured to supply a second current to the interconnection structure impedance measurement circuit when the first switch K1 is turned off and the second switch K2 and the third switch K3 are turned on. Here, the second current is larger than the first current. That is, the constant current source provides current stress in the power supply mode. In the power supply mode, the first branch is turned on, and the second branch and the third branch are turned off.

[0045] The mutual connection structure impedance measuring device includes a constant current source, two voltmeters, three switches, a mutual connection structure formed in parallel by three resistors (R5), and four fixed resistors. The resistors connected in parallel are produced in the same batch of the same type, and it is guaranteed that their resistance values are approximately equal. The resistance values (R1, R2, R1', R2') of the four fixed resistors are known. The voltmeter V connects the first branch and the second branch, and connects the first branch and the third branch. In a total of three parallel branches, the first branch includes one first switch K1, a first mutual connection structure formed by a plurality of resistors in parallel, and a second mutual connection structure (single mutual connection structure). The second branch includes one second switch K2 and two fixed resistors R1 and R2. The third branch includes one third switch K3 and two fixed resistors R1' and R2'. R2' is about three times that of R1', and the value rule is the same as that of R1 and R2. However, the values of R1' and R2' are not exactly equal to the values of R1 and R2. In the embodiment of the present disclosure, taking the example that three fifth resistors are connected in parallel to obtain the first mutual connection structure, that is, n = 3. Correspondingly, R2' is about three times that of R1'. As long as n≧2 is guaranteed, the impedance R4 of the second mutual connection structure can be calculated by formula (5). The larger the value of n, the higher the measurement accuracy. When measuring the impedance of the single mutual connection structure (that is, the impedance R4 of the second mutual connection structure) in the reliability experiment, the first mutual connection structure and the second mutual connection structure are located in the aging experiment environment, connect the second current supplied from the constant current source, obtain the first voltage Vg and the second voltage Vg' through measurement, and substitute them into formula (5) to obtain the impedance R4 of the single mutual connection structure. By controlling the on and off of the switch circuit by the control module, real-time monitoring of the impedance R4 of the single mutual connection structure is realized. When R4 reaches the invalid judgment criterion, the experiment ends, the invalid time of the single mutual connection structure can be accurately obtained, and the life of the whole component and the system characteristics can be predicted.

[0046] The reliability experiment of the interconnection structure rapidly deteriorates the interconnection structure by applying temperature / current stress. However, the deterioration process is actually a process of internal damage to the interconnection structure, such as phenomena like voids, fractures, and the formation of metal compounds. Due to these damages, the resistance of the interconnection structure increases. By measuring Vg and Vg’ and substituting them into equations (5) and (6), the values of the impedance R3 of the first interconnection structure and the impedance R4 of the second interconnection structure can be calculated, realizing the monitoring of the impedance of the interconnection structure. The first interconnection structure is realized by connecting a plurality of resistors in parallel. Since the current flowing through the first interconnection structure can be made smaller than the current flowing through the second interconnection structure, the deterioration of the first interconnection structure is slower than that of the second interconnection structure under current stress. If three copper metal resistors are connected in parallel to form the first interconnection structure, generally the current density exponent n = 2. As can be seen from the Blackman equation, the life of the first interconnection structure is about 10 times that of a single interconnection structure. The changes in Vg and Vg’ represent the deterioration of R4. Thus, the change in the impedance of a single interconnection structure can be accurately obtained, the deterioration situation of the single interconnection structure can be explored, its failure occurrence time can be accurately obtained, and ultimately the accuracy of predicting the characteristic life of components and the entire system can be improved.

[0047] Embodiments of the present disclosure further provide an interconnection structure impedance measurement method applicable to the interconnection structure impedance measurement device described in FIG. 8. As shown in FIG. 10, the impedance measurement method of the interconnection structure includes the following steps.

[0048] Step 11: Supply a first current to the interconnection structure impedance measurement circuit. In this step, the constant current source supplies a first current to the interconnection structure impedance measurement circuit.

[0049] Step 12: Control the interconnect structure impedance measurement circuit to be in the first state, detect the first voltage between the first branch path and the second branch path. Here, in the first state, the first switch and the second switch are turned off and the third switch is turned on.

[0050] In this step, the control module controls the first switch K1 and the second switch K2 to be off and the third switch K3 to be on, and measures the bridge voltage Vg with a voltmeter.

[0051] Step 13: Control the interconnect structure impedance measurement circuit to switch from the first state to the second state, detect the second voltage between the first branch path and the third branch path. Here, in the second state, the first switch and the third switch are turned off and the second switch is turned on.

[0052] In this step, the control module controls the first switch K1 and the third switch K3 to be off and the switch K2 to be on, and measures the bridge voltage Vg’ with a voltmeter. In the first state and the second state, the constant current source is in the measurement mode.

[0053] Step 14: Stop supplying the first current to the interconnect structure impedance measurement circuit, and calculate the impedances of the first interconnect structure and the second interconnect structure based on the first resistor, the second resistor, the third resistor, the fourth resistor, the first voltage, the second voltage, and the first current.

[0054] In this step, turn off the constant current source, and the control module obtains R3 and R4 according to formulas (5) and (6).

[0055] The embodiment of the present disclosure further provides an interconnect structure impedance measurement method for performing a reliability test, which is applicable to the interconnect structure impedance measurement device shown in FIG. 9. As shown in FIG. 11, the method includes the following steps.

[0056] Step 11: Supply a first current to the interconnect structure impedance measurement circuit. Step 12: Control the interconnection structure impedance measurement circuit to be in the first state, and detect the first voltage between the first branch path and the second branch path. Here, in the first state, the first switch and the second switch are turned off and the third switch is turned on.

[0057] Step 13: Control the interconnection structure impedance measurement circuit to switch from the first state to the second state, and detect the second voltage between the first branch path and the third branch path. In the second state, the first switch and the third switch are turned off and the second switch is turned on.

[0058] Step 14: Stop supplying the first current to the interconnection structure impedance measurement circuit, and calculate the impedances of the first interconnection structure and the second interconnection structure based on the first resistor, the second resistor, the third resistor, the fourth resistor, the first voltage, the second voltage, and the first current.

[0059] Step 15: Control the interconnection structure impedance measurement circuit to switch from the second state to the third state. In the third state, the first switch is turned off and the second switch and the third switch are turned on.

[0060] In this step, the control module controls the first switch K1 to be turned off and the second switch K2 and the third switch K3 to be turned on.

[0061] Step 16: Provide a second current to the interconnection structure impedance measurement circuit within a preset period to improve the current stress and accelerate the deterioration of the interconnection structure.

[0062] In this step, the control module controls the constant current source to switch to the power supply mode to provide the required current stress. In the power supply mode, the current flowing through the first branch path is relatively large compared to the measurement mode.

[0063] Step 17: Measure the impedance of the second interconnection structure, compare it with a preset invalid impedance value, and end the measurement when the impedance of the second interconnection structure reaches the invalid impedance.

[0064] The invalid impedance value is the resistance invalid standard value. In this step, steps 11 to 14 are repeated until the impedance of the second interconnection structure reaches the invalid standard, and then the measurement is ended.

[0065] In some embodiments, the interconnection structure impedance measurement method further includes a step of recording the invalid time from the start of the supply of the second current to the end of the measurement, and a step of performing a reliability analysis of the second interconnection structure based on the invalid time.

[0066] In a reliability test, it is mostly necessary to continuously monitor the change in the resistance value. The interconnection structure impedance measurement method of the embodiments of the present disclosure can not only measure the initial resistance value of the impedance, but also accurately measure the minute impedance changes that occur during the test process, and can accurately obtain the invalid time by setting the invalid standard, which is very important for reliability prediction analysis.

[0067] In the experiment of electromigration reliability, in the application process of microelectronic products, under the action of long-term current stress, especially in the interconnection structure, there is a phenomenon that metal atoms are displaced along the electron movement direction. As a result, invalidations such as holes and fractures occur in the interconnection structure, further increasing the impedance of the interconnection structure, and even opening up, damaging the entire device or product. As miniaturization progresses in the field of microelectronics, the dimensions of the interconnection structure are constantly shrinking, the current density is constantly increasing, and the electromigration phenomenon is becoming increasingly serious. Therefore, before the actual product is applied, the electromigration reliability test is also becoming increasingly necessary. Evaluating the reliability of electromigration of a single interconnection structure is becoming increasingly important in the electromigration reliability test. Due to the small impedance of a single interconnection structure, it becomes more difficult to capture the change in impedance, and the accuracy of the electromigration reliability test poses a great challenge. By adopting the interconnection structure impedance measurement method of the embodiments of the present disclosure, not only the initial value of the impedance of a single interconnection structure but also the change value of the impedance can be accurately monitored, and the problems existing in the electromigration reliability test of a single interconnection structure can be solved.

[0068] The embodiments of the present disclosure can monitor the impedance of a single interconnection structure in a reliability experiment and can measure the real-time monitoring of the impedance of the interconnection structure and the micro-resistance. The interconnection structure impedance measurement circuit is the core part that can achieve accurate measurement. It measures the sample and communicates with the interconnection structure impedance measurement circuit, is powered by a constant current source, and the voltmeter measures the voltage difference between the branch paths. Then, by performing voltage measurement repetitively, the impedance of the measurement target sample can be calculated according to formulas (5) and (6). By switching the branch path switch, the impedance of the interconnection structure can be measured in real time.

[0069] Embodiments of the present disclosure can be applied to the high-speed detection of the package bonding process, including interconnect pads, interconnect wires, etc. By analyzing the measured impedance, the stability of the bonding process can be reflected, and it can be applied to the reliability experiment of key components composed of the interconnect structure. By monitoring the impedance in real time, the invalidation time of the interconnect structure can be obtained, and further the characteristic life of the component or the whole system can be predicted. Particularly for the electromigration reliability test, the solution of the embodiments of the present disclosure has been applied to the life evaluation of the package pads in the CPU item. It can also be applied to some impedance measuring devices to accurately measure the micro impedance.

[0070] Those skilled in the art will understand that all or part of the steps in the methods disclosed above and the functional modules / units in the devices can be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware embodiments, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components. For example, one physical component may have multiple functions, or one function or step may be executed by several physical components in cooperation. Some or all of the physical components may be implemented as software executed by a processing device (e.g., a central processing unit, a digital signal processor, or a microprocessor), as hardware, or as an integrated circuit such as an application-specific integrated circuit. Such software may be disposed on a computer-readable medium, and the computer-readable medium may include a computer storage medium (or non-transitory medium) and a communication medium (or transitory medium). As is well known to those skilled in the art, the term computer storage medium includes any method or technology implemented for storing information such as computer-readable commands, data structures, program modules, or other data, including volatile and non-volatile, removable and non-removable media. The computer storage medium includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. Also, it is known to those skilled in the art that a communication medium typically includes other data in a modulated data signal such as computer-readable commands, data structures, program modules, or a carrier wave or other carrier mechanism, and may include any information distribution medium.

[0071] This specification discloses exemplary embodiments and uses specific terms, but they are only for general description and should be so construed, not for the purpose of limitation. Unless otherwise explicitly stated, in some embodiments, it is obvious to those skilled in the art that the features, characteristics, and / or elements described in combination with a specific embodiment can be used alone or in combination with the features, characteristics, and / or elements described in combination with other embodiments. Therefore, those skilled in the art will understand that various modifications can be made in various forms and details without departing from the scope of the present disclosure as defined by the appended claims.

Claims

1. Including a first branch path, a second branch path, and a third branch path connected in parallel, the first branch path includes a first interconnection structure, a second interconnection structure, and a first switch connected in series, the second branch path includes a first resistor, a second resistor, and a second switch connected in series, and the third branch path includes a third resistor, a fourth resistor, and a third switch connected in series. The impedance of the first interconnection structure and the impedance of the second interconnection structure are specified based on a first voltage between the first branch path and the second branch path, a second voltage between the first branch path and the second branch path, the first resistor, the second resistor, the third resistor, the fourth resistor, and a first current input to the interconnection structure impedance measurement circuit. The first voltage is detected when the first switch and the second switch are off and the third switch is on, and the second voltage is detected when the first switch and the third switch are off and the second switch is on. An interconnection structure impedance measurement circuit.

2. The resistance value of the first resistor is not equal to the resistance value of the third resistor, and the resistance value of the second resistor is not equal to the resistance value of the fourth resistor. The interconnection structure impedance measurement circuit according to Claim 1.

3. The first interconnection structure and the second interconnection structure are connected to a printed circuit board (PCB), the interconnection structure impedance measurement circuit is provided on the PCB, or the interconnection structure impedance measurement circuit is provided in an interconnection structure impedance measurement device. The interconnection structure impedance measurement circuit according to Claim 1.

4. The first interconnection structure is at least two fifth resistors connected in parallel, the resistance value of each fifth resistor is the same, and the resistance value of the fifth resistor is equal to the resistance value of the second interconnection structure, or The first interconnection structure is a conducting wire. The interconnection structure impedance measurement circuit according to any one of Claims 1 to 3.

5. The first interconnection structure is n fifth resistors connected in parallel, where n is an integer of 2 or more. The resistance value of the second resistor is n times the resistance value of the first resistor, and the resistance value of the fourth resistor is n times the resistance value of the third resistor. The interconnection structure impedance measurement circuit according to Claim 4.

6. A constant current source, a voltage detection module, a control module, and the mutual connection structure impedance measurement circuit according to any one of claims 1 to 5, The constant current source is connected to the first branch, the second branch, and the third branch, and is configured to supply a first current to the mutual connection structure impedance measurement circuit when the first switch and the second switch are off and the third switch is on, or when the first switch and the third switch are off and the second switch is on. The voltage detection module is respectively connected to the first branch, the second branch, and the third branch, and is configured to detect a first voltage between the first branch and the second branch when the first switch and the second switch are off and the third switch is on, and to detect a second voltage between the first branch and the second branch when the first switch and the third switch are off and the second switch is on. The control module is configured to control the constant current source to supply the first current to the mutual connection structure impedance measurement circuit, to control the first switch, the second switch, and the third switch to be turned on or off, to acquire the first voltage and the second voltage detected by the voltage detection module, and to calculate the impedance of the first mutual connection structure and the impedance of the second mutual connection structure based on the first resistor, the second resistor, the third resistor, the fourth resistor, the first voltage, the second voltage, and the first current. A mutual connection structure impedance measurement device.

7. The mutual connection structure impedance measurement circuit is the mutual connection structure impedance measurement circuit according to claim 4 or 5, The constant current source is further configured to supply a second current greater than the first current to the mutual connection structure impedance measurement circuit when the first switch is off and the second switch and the third switch are on. The mutual connection structure impedance measurement device according to claim 6.

8. A method for measuring the impedance of a mutual connection structure applied to the mutual connection structure impedance measurement device according to claim 6, A step of supplying a first current to the mutual connection structure impedance measurement circuit, Controlling the interconnect structure impedance measurement circuit to a first state to detect a first voltage between the first branch path and the second branch path, and in the first state, turning off the first switch and the second switch and turning on the third switch; Controlling the interconnect structure impedance measurement circuit to switch from the first state to a second state to detect a second voltage between the first branch path and the third branch path, and in the second state, turning off the first switch and the third switch and turning on the second switch; Stopping supplying a first current to the interconnect structure impedance measurement circuit, and calculating the impedances of the first interconnect structure and the second interconnect structure based on the first resistor, the second resistor, the third resistor, the fourth resistor, the first voltage, the second voltage, and the first current. A method for measuring the impedance of an interconnect structure.

9. A method for measuring the impedance of an interconnect structure applied to the interconnect structure impedance measurement device according to claim 7, Measuring the impedance of the second interconnect structure by the method according to claim 8; Controlling the interconnect structure impedance measurement circuit to switch from the second state to a third state, and in the third state, turning off the first switch and turning on the second switch and the third switch; Providing a second current to the interconnect structure impedance measurement circuit within a preset period to increase current stress and accelerate the degradation of the interconnect structure; Measuring the impedance of the second interconnect structure by the method according to claim 8, comparing it with a preset invalid impedance value, and ending the measurement when the impedance of the second interconnect structure reaches the invalid impedance value. A method for measuring the impedance of an interconnect structure.

10. Recording the invalid time from the start of supplying the second current to the end of the measurement; Further including performing a reliability analysis on the second interconnect structure based on the invalid time. The method according to claim 9.

Images