Interconnection structure impedance measurement circuit, measurement device, and measurement 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 into this disclosure by reference.

[0002] [Technical Field] The 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 lines 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 resistive impedance of many small structures, such as interconnected metal wires, researchers have proposed various ideas and methods, among which the four-probe method is widely recognized as an accurate measurement method. However, the four-probe method has several drawbacks in its application. It cannot measure resistive impedance on a large scale in real time, the measurement is complex and costly, and it is inconvenient because it requires manual measurement. The classic Wheatstone bridge structure can also be used to measure minute resistances. However, the Wheatstone bridge structure has many limitations, requiring three known resistive impedances, and it is necessary to select appropriate resistive impedances to balance the bridge. Furthermore, obtaining unknown resistive impedances by solving equations is difficult and limits its application. Therefore, there is a need for a device or method that can accurately measure the impedance of interconnected structures, is scalable, automated, and easy to implement. [Overview of the project] [Problems that the invention aims to solve]

[0005] This disclosure provides an interconnection structure impedance measurement circuit, a measurement device, and a measurement method. In a first embodiment, the embodiment of the present disclosure includes a first branch, a second branch, and a third branch connected in parallel, the first branch including a first interconnection structure, a second interconnection structure, and a first switch connected in series, the second branch including a first resistor, a second resistor, and a second switch connected in series, the third branch including 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, the first voltage between the first branch and the second branch, the first branch and the 3The present invention provides an interconnect structure impedance measurement circuit that determines the impedance based on a second voltage between the branch line, the first resistor, the second resistor, the third resistor, the fourth resistor, and a first current input to the interconnect structure impedance measurement circuit, wherein the first voltage is detected when the first and second switches are off and the third switch is on, and the second voltage is detected when the first and third switches are off and the second switch is on.

[0006] In another embodiment, an embodiment of the present disclosure comprises a constant current source, a voltage detection module, a control module, and the interconnect structure impedance measurement circuit described above. 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 interconnect 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, the second branch and the third branch, respectively, and detects 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 detects the first branch and the third branch when the first switch and the third switch are off and the second switch is on. 3 Further, an interconnect structure impedance measuring device is provided, configured to detect a second voltage between a branch line, wherein the control module controls the constant current source to supply the first current to the interconnect structure impedance measuring circuit, controls the first switch, the second switch and the third switch to turn on or off, obtains the first voltage and the second voltage detected by the voltage detection module, and calculates the impedance of the first interconnect structure and the impedance of the second interconnect structure based on the first resistance, the second resistance, the third resistance, the fourth resistance, the first voltage, the second voltage and the first current.

[0007] In another embodiment, an embodiment of the present disclosure provides a method for measuring the impedance of an interconnect structure, which is applied to the interconnect structure impedance measuring device described above, and further includes the steps of: supplying a first current to the interconnect structure impedance measuring circuit; controlling the interconnect structure impedance measuring circuit to a first state to detect a first voltage between the first branch and the second branch, in which the first switch and the second switch are turned off and the third switch is turned on; controlling the interconnect structure impedance measuring circuit to switch from the first state to a second state to detect a second voltage between the first branch and the third branch, in which the first switch and the third switch are turned off and the second switch is turned on; stopping the supply of the first current to the interconnect structure impedance measuring circuit, and calculating the impedances of the first interconnect structure and the second interconnect structure based on the first resistance, the second resistance, the third resistance, the fourth resistance, the first voltage, the second voltage, and the first current.

[0008] In another embodiment, an embodiment of the present disclosure further provides a method for measuring the impedance of an interconnect structure, which is applied to the interconnect structure impedance measuring device described above, and includes the steps of: measuring the impedance of the second interconnect structure by the method described above; controlling the interconnect structure impedance measuring 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 and third switches are turned on; providing a second current to the interconnect structure impedance measuring circuit within a preset period of time to increase current stress and accelerate the deterioration of the interconnect structure; measuring the impedance of the second interconnect structure by the method described above, comparing it with a preset inactive impedance value, and terminating the measurement when the impedance of the second interconnect structure reaches the inactive impedance value. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an interconnection structure impedance measurement circuit provided in an embodiment of the present disclosure. [Figure 2] This is a schematic diagram of the physical structure corresponding to the measurement circuit in Figure 1. [Figure 3] This is a circuit diagram of a traditional Wheatstone bridge test resistor. [Figure 4] This is a schematic diagram of an interconnection structure impedance measurement circuit provided in yet another embodiment of the present disclosure. [Figure 5] This is a schematic diagram of the physical structure corresponding to the measurement circuit in Figure 4. [Figure 6] This is a schematic diagram of a measuring device for a measuring circuit package provided in the embodiments of this disclosure. [Figure 7] This is a schematic diagram showing how the measurement circuit provided in the embodiments of this disclosure is packaged on a PCB. [Figure 8] This is a schematic diagram of the structure of an interconnection structure impedance measuring device provided by an embodiment of the present disclosure. [Figure 9] This is a schematic diagram of the structure of an interconnection structure impedance measuring device provided by yet another embodiment of the present disclosure. [Figure 10] This is a flowchart of the impedance measurement method for an interconnection structure provided in the embodiments of this disclosure. [Figure 11] This is a flowchart of a method for measuring the impedance of an interconnection structure provided in yet another embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] The following sections provide a more detailed description of exemplary embodiments with reference to the drawings, but these exemplary embodiments can be embodied in different ways and should not be construed as being limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to make this disclosure detailed and complete, so that those skilled in the art may fully understand the scope of this disclosure.

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

[0012] The terms used herein are for the purpose of describing specific embodiments and are not intended to limit the disclosure. Where otherwise the context makes clear, the singular forms “one” and “the said” are intended to include the plural forms. Furthermore, where the terms “including” and / or “consisting of” are used herein, they indicate the presence of a particular feature, whole, step, operation, element, and / or component, but do not preclude the presence of one or more other features, wholes, steps, operations, elements, components, and / or groups thereof, or the addition of such features.

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

[0014] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as those commonly understood by those skilled in the art. Furthermore, terms defined in common dictionaries should be understood to have the same meaning as they have in the context of the relevant art and this disclosure, and should not be interpreted as having an idealized or overly formal meaning unless explicitly limited herein.

[0015] In addition to the fact that the structures of the interconnecting metal wires and interconnecting pads are both very small, due to their good metallic conductivity, accurately measuring the resistance value has always been a pain point in the industry. In reliability testing, the interconnecting structure is also an important focus of the experiment. In long-term temperature / current stress, the degree of degradation or the presence or absence of faults 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 very small and the changes occurring therein are extremely small, 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 K.sub.1 connected in series. The second branch path includes a first resistor R.sub.1, a second resistor R.sub.2, and a second switch K.sub.2 connected in series. The third branch path includes a third resistor R.sub.1', a fourth resistor R.sub.2', and a third switch K.sub.3 connected in series.

[0017] The impedance R.sub.3 of the first interconnecting structure and the impedance R.sub.4 of the second interconnecting structure are determined based on a first voltage V.sub.g between the first branch path and the second branch path, a second voltage V.sub.g' between the first branch path and the third branch path, the first resistor R.sub.1, the second resistor R.sub.2, the third resistor R.sub.1', the fourth resistor R.sub.2', 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 the branch paths, 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 so that the branch paths of the mutual connection structure are 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 the impedance of a single mutual connection structure in a reliability experiment in real time.

[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 by, for example, 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] As shown in Figures 1 and 2, R3 is the impedance of the first interconnection structure, R4 is the impedance of the second interconnection 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, the values ​​of the impedance R3 of the first interconnection structure and the impedance R4 of the second interconnection structure can be calculated by solving a system of nonlinear equations.

[0023] According to Kirchhoff's laws, the following equation is obtained.

[0024]

number

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

[0026]

number

[0027] The requirements for selecting the resistance values ​​of the four resistors R1, R2, R1', and R2' are not particularly high. However, when measuring the impedance of a microstructure, setting R1 / R2 ≈ R1' / R2' can further improve measurement accuracy.

[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] The embodiments of this disclosure can be applied to multiple technical fields, including electronic packaging, reliability testing, and precision measurement. In the manufacturing process of electronic packages, welded interconnections are common, and the quality of the interconnect structure directly affects the quality of the product. Therefore, the importance of quickly evaluating the welding quality of the interconnect structure is undeniable. Poor welding is reflected in increased resistance, and the interconnect structure impedance measurement circuit of the embodiments of this disclosure can be used to quickly detect the impedance of the interconnect structure, serving as a detection tool for real-time monitoring of changes in the production process. Similarly, throughout the chip manufacturing process, interconnect structures often have contact resistance, making it difficult to determine their resistance values. The interconnect structure impedance measurement circuit of the embodiments of this disclosure can be used to quickly and accurately measure the impedance of micro-interconnection structures, providing significant application value in areas such as evaluating the performance of the entire system.

[0030] Reliability testing often requires continuous monitoring of changes in impedance values. Therefore, by improving the interconnect structure impedance measurement circuit of the embodiment of this disclosure, it is possible to achieve monitoring of the impedance of a single interconnect structure in reliability experiments.

[0031] In some embodiments, the unit of the impedance R3 of the first interconnection structure is milliohms. That is, the first interconnection structure in the interconnection structure impedance measurement circuit is an interconnection structure with low impedance, and a single interconnection structure including the second interconnection structure is formed in the first branch line.

[0032] The first interconnection structure with low impedance may have multiple implementation forms. For example, the first interconnection structure may be at least two fifth resistors connected in parallel, each of which has the same resistance value, and the resistance value of the fifth resistors is equal to the resistance value of the second interconnection structure, or the first interconnection structure may be implemented by a wire.

[0033] In the embodiments of this disclosure, as shown in Figures 4 and 5, the first interconnection structure consists of three parallel-connected fifth resistors R5. The number of parallel-connected fifth resistors R5 continues to increase, and the more fifth resistors R5 there are, the more accurate the measurement of the impedance of the single interconnection structure (i.e., the impedance R4 of the second interconnection structure) becomes. 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 a fifth resistor R5 (where n is an integer greater than or equal to 2) connected in parallel, 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'. In other words, the selection of resistance values ​​for the first resistor R1, second resistor R2, third resistor R1', and fourth resistor R2' in the second and third branches is related to the number of fifth resistors R5 connected in parallel in the first interconnection structure. As shown in Figure 4, after the three fifth resistors R5 are connected in parallel, they are connected in series with another single interconnection structure (i.e., the second interconnection structure R4), and the impedance R4 of the second interconnection structure is approximately three times the impedance of the three fifth resistors R5.

[0035] Figures 6 and 7 show two scenarios in which the interconnection structure impedance measurement circuit is applied, and the two measurement design options shown in Figures 6 and 7 can be adopted for different measurement needs.

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

[0037] As shown in Figure 7, when an interconnect structure impedance measurement circuit is integrated on a PCB board and the impedance R3 of the first interconnect structure and the impedance R4 of the second interconnect structure are measured, the interconnect structure impedance measurement device only needs to be supplied with current. In the scenario shown in Figure 7, the construction of the measurement system is simple and measurement is convenient, but the difficulty of designing the PCB layout increases, the wear and tear on the layout increases, and the cost increases.

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

[0039] The constant current source is connected to the first branch circuit, the second branch circuit, and the third branch circuit, and supplies a first current to the interconnection structure impedance measurement circuit 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.

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

[0041] The control module is configured to control a constant current source to supply a first current to the interconnect structure impedance measurement circuit, to control the on / off state of the first switch K1, the second switch K2, and the third switch K3, to acquire the first voltage Vg and the second voltage Vg' detected by the voltage detection module, and to calculate the impedance R3 of the first interconnect structure and the impedance R4 of the second interconnect structure 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.

[0042] The interconnection structure impedance measuring device includes a constant current source, two voltmeters, three switches, two interconnection structures, and four resistors, where the two interconnection structures are the resistors to be measured (R3, R4), and the resistance values ​​of the four resistors (R1, R2, R1', R2') are known. In a total of three parallel branch lines, the first branch line includes one first switch K1, a first interconnection structure, and a second interconnection structure; the second branch line includes one second switch K2 and two fixed resistors R1 and R2; and the third branch line includes one third switch K3 and two fixed resistors R1' and R2'. The voltmeter V connects the first and second strips, and the first and third strips. When measuring the impedances R3 and R4 of interconnection structures, a first current supplied from a constant current source is connected, and the first voltage Vg and second voltage Vg' are obtained by measurement. By substituting these values ​​into equations (5) and (6) above, the impedance R3 of the first interconnection structure and the impedance R4 of the second interconnection structure can be determined simultaneously. By controlling the on and off states of switches (K1, K2, K3) using a control module, real-time monitoring of the impedances R3 of the first interconnection structure and R4 of the second interconnection structure can be achieved.

[0043] The principle for real-time monitoring of the impedance of interconnected structures can also be applied to the accurate measurement of the resistive impedance of microstructures. Measuring the resistive impedance of microstructures usually does not require real-time switching of control modules, and the core circuit structure is almost identical. In both cases, Vg and Vg' are measured, and R3 and R4 are determined by substituting them into equations (5) and (6). Accuracy is improved by directly measuring the impedance of the resistor and determining the resistance by measuring the voltage and using the formula. Here, by selecting the resistance values ​​of the four resistors R1, R2, R1', and R2', it is possible to make R1 / R2 ≈ R1' / R2', further improving the measurement accuracy.

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

[0045] The interconnect structure impedance measuring device includes a constant current source, two voltmeters, three switches, an interconnect structure formed in parallel by three resistors (R5), and four fixed resistors, where the resistors connected in parallel are produced in the same batch of the same type, ensuring that their resistance values ​​are approximately equal, and the resistance values ​​of the four fixed resistors (R1, R2, R1', R2') are known. Voltmeter V connects the first branch to the second branch and the first branch to the third branch. In a total of three parallel branch circuits, the first branch circuit includes one first switch K1, a first interconnection structure in which multiple resistors are formed in parallel, and a second interconnection structure (single interconnection structure); the second branch circuit includes one second switch K2 and two fixed resistors R1 and R2; and the third branch circuit includes one third switch K3 and two fixed resistors R1' and R2', where R2' is approximately three times R1', and the value rules are the same as for R1 and R2. However, the values ​​of R1' and R2' are not exactly equal to the values ​​of R1 and R2. In an embodiment of this disclosure, we will explain using the example of obtaining the first interconnection structure by arranging three fifth resistors in parallel, i.e., n=3, and accordingly, R2' is approximately three times R1'. Furthermore, as long as n≧2 is guaranteed, the impedance R4 of the second interconnection structure can be calculated by equation (5), and the larger the value of n, the higher the measurement accuracy. In reliability experiments, when measuring the impedance of a single interconnect structure (i.e., the impedance R4 of the second interconnect structure), the first and second interconnect structures are placed in an aging experiment environment, a second current supplied from a constant current source is connected, and the first voltage Vg and second voltage Vg' are obtained by measurement. By substituting these into equation (5), the impedance R4 of the single interconnect structure can be determined. A control module controls the on / off state of the switch circuit to achieve real-time monitoring of the impedance R4 of the single interconnect structure. When R4 reaches the invalidation criterion, the experiment ends, the invalidation time of the single interconnect structure is accurately obtained, and the lifespan of the entire component and system features can be predicted.

[0046] Reliability experiments of interconnect structures rapidly degrade them by applying temperature / current stress. This degradation process is actually a process of internal damage to the interconnect structure, such as voids, fractures, and the formation of metallic compounds. These damages increase the resistance of the interconnect structure, and by measuring Vg and Vg' and substituting them into equations (5) and (6), the impedance R3 of the first interconnect structure and the impedance R4 of the second interconnect structure can be calculated, enabling monitoring of the interconnect structure's impedance. The first interconnect structure is realized by connecting multiple resistors in parallel, and the current flowing through the first interconnect structure can be made smaller than the current flowing through the second interconnect structure. Therefore, under current stress, the degradation of the first interconnect structure is slower than that of the second interconnect structure. If three copper metal resistors are connected in parallel to form the first interconnect structure, the current density index n is generally 2, and as can be seen from the Blackman equation, the lifespan of the first interconnect structure is approximately 10 times that of a single interconnect structure. Since changes in Vg and Vg' represent the degradation of R4, it is possible to accurately obtain changes in the impedance of a single interconnect structure, investigate the degradation situation of the single interconnect structure, accurately obtain its failure time, and ultimately improve the accuracy of predicting the characteristic lifespan of the component and the entire system.

[0047] Embodiments of this disclosure further provide a method for measuring the impedance of an interconnect structure, applicable to the interconnect structure impedance measuring apparatus described in Figure 8. As shown in Figure 10, the method for measuring the impedance of the interconnect structure includes the following steps.

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

[0049] Step 12: Control the interconnection structure impedance measurement circuit to enter a first state and detect the first voltage between the first branch and the second branch. In this first state, the first and second switches 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 turn off and the third switch K3 to turn on, and measures the bridge voltage Vg using a voltmeter.

[0051] Step 13: Control the interconnection structure impedance measurement circuit to switch from the first state to the second state to detect the second voltage between the first branch and the third branch, where in the second state, the first and third switches 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 switch K2 to be on, and measures the bridge voltage Vg' using a voltmeter. In the first and second states, the constant current source is in measurement mode.

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

[0054] In this step, the constant current source is turned off, and the control module determines R3 and R4 using equations (5) and (6).

[0055] Embodiments of the present disclosure further provide a method for measuring interconnect structure impedance for performing reliability testing, which is applied to the interconnect structure impedance measuring apparatus shown in Figure 9, and as shown in Figure 11, the method includes the following steps.

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

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

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

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

[0061] Step 16: Provide a second current to the interconnect structure impedance measurement circuit within a predetermined period to increase current stress and accelerate the degradation of the interconnect structure.

[0062] In this step, the control module controls the constant current source to switch to power supply mode, providing the necessary current stress, and in power supply mode, the current flowing through the first branch is relatively larger than in measurement mode.

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

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

[0065] In some embodiments, the interconnect structure impedance measurement method further includes the steps of recording the idle time from the start of supplying the second current to the end of the measurement, and performing a reliability analysis of the second interconnect structure based on the idle time.

[0066] In reliability testing, it is often necessary to continuously monitor changes in resistance values. The interconnect structure impedance measurement method of the embodiment of this disclosure can not only measure the initial resistance value of the impedance, but also accurately measure minute impedance changes that occur during the test process, and can accurately obtain the invalid time by setting an invalid criterion, which is very important for reliability predictive analysis.

[0067] In electromigration reliability experiments, microelectronic products, during the application process, are subjected to current stress for extended periods. In particular, interconnect structures experience displacement of metal atoms along the direction of electron movement, leading to defects such as holes and fractures in the interconnect structure. Furthermore, this increases the impedance of the interconnect structure, potentially causing it to open up and damage the entire device or product. As miniaturization progresses in the field of microelectronics, the dimensions of interconnect structures are constantly shrinking, current density is constantly increasing, and the electromigration phenomenon is becoming increasingly severe. Therefore, electromigration reliability testing is becoming increasingly necessary before actual products are applied, and evaluating the reliability of electromigration of single interconnect structures is becoming increasingly important in electromigration reliability testing. Because the impedance of single interconnect structures is small, changes in impedance are more difficult to capture, posing a significant challenge to the accuracy of electromigration reliability testing. By adopting the interconnect structure impedance measurement method of the embodiments of this disclosure, not only the initial value of the impedance of a single interconnect structure but also the change in impedance can be accurately monitored, solving the problems present in electromigration reliability testing of single interconnect structures.

[0068] Embodiments of this disclosure allow for monitoring the impedance of a single interconnect structure in reliability experiments, enabling real-time monitoring of the interconnect structure's impedance and measurement of minute resistances. The interconnect structure impedance measurement circuit is a core component that ensures accurate measurements. A sample is measured, the interconnect structure impedance measurement circuit is connected, and powered by a constant current source, the voltmeter measures the voltage difference between the branch lines, and then repeats the voltage measurement to calculate the impedance of the sample under measurement using equations (5) and (6). The impedance of the interconnect structure can be measured in real time by switching the branch line switch.

[0069] The embodiments of this disclosure can be applied to high-speed detection of package bonding processes, including interconnect pads and interconnect metal wires, and by analyzing the measured impedance, the stability of the bonding process can be reflected. It can be applied to reliability testing of critical components consisting of interconnect structures, and by monitoring impedance in real time, the invalid time of the interconnect structure can be obtained, and further, the characteristic lifetime of the component or the entire system can be predicted. In particular, for electromigration reliability testing, the solutions of the embodiments of this disclosure are applied to lifetime evaluation of package pads in the CPU component. It can also be applied to several impedance measuring instruments to accurately measure minute impedances.

[0070] Those skilled in the art will understand that all or some of the steps in the methods disclosed above, and of the functional modules / units in the apparatus, can be implemented as software, firmware, hardware, or a suitable combination thereof. In hardware embodiments, the distinctions between functional modules / units mentioned above do not necessarily correspond to distinctions between physical components. For example, one physical component may have multiple functions, or one function or step may be performed by several physical components working together. Some or all of the physical components may be implemented as software executed by a processing unit (e.g., a central processing unit, a digital signal processor, or a microprocessor), as hardware, or as an integrated circuit such as a dedicated integrated circuit. Such software may be located on a computer-readable medium, which may include computer storage media (or non-temporary media) and communication media (or temporary media). As is well known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technique for storing information such as computer-readable commands, data structures, program modules, or other data. Computer storage media include, but are 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 media that can be used to store desired information and can be accessed by a computer. It is also known to those skilled in the art that communication media may include any information distribution media, and typically include computer-readable commands, data structures, program modules, or other data such as modulated data signals, carrier waves or other carrier mechanisms.

[0071] This specification discloses exemplary embodiments and uses specific terminology, but these are for general purposes only and should be interpreted as such, and are not intended to be limiting. Unless otherwise explicitly noted, it will be obvious to those skilled in the art that in some embodiments, features, characteristics, and / or elements described in combination with a particular embodiment can be used alone or in combination with features, characteristics, and / or elements described in combination with other embodiments. Accordingly, those skilled in the art will understand that modifications can be made in various forms and details, without departing from the scope of this disclosure as set forth by the appended claims.

Claims

1. The system includes a first branch, a second branch, and a third branch connected in parallel, the first branch including a first interconnection structure, a second interconnection structure, and a first switch connected in series, the second branch including a first resistor, a second resistor, and a second switch connected in series, and the third branch including a third resistor, a fourth resistor, and a third switch connected in series. The impedances of the first interconnection structure and the second interconnection structure are determined based on a first voltage between the first branch and the second branch, a second voltage between the first branch and the third branch, 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 and second switches are off and the third switch is on, and the second voltage is detected when the first and third switches are off and the second switch is on. Circuit for measuring interconnection structure impedance.

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. A circuit for measuring interconnection structure impedance according to claim 1.

3. The first interconnection structure and the second interconnection structure are connected to a printed circuit board (PCB), and 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. A circuit for measuring interconnection structure impedance according to claim 1.

4. The first interconnection structure is a fifth resistor consisting of at least two resistors connected in parallel, the resistance value of each fifth resistor being the same, and the resistance value of the fifth resistor being equal to the resistance value of the second interconnection structure, or The first interconnection structure described above is a conductor. A circuit for measuring interconnection structure impedance according to claim 1.

5. The first interconnection structure is a fifth resistor connected in parallel with n resistors, where n is an integer of 2 or more. The resistance value of the aforementioned second resistor is n times the resistance value of the aforementioned first resistor, and the resistance value of the aforementioned fourth resistor is n times the resistance value of the aforementioned third resistor. A circuit for measuring interconnection structure impedance according to claim 4.

6. The system comprises a constant current source, a voltage detection module, a control module, and an interconnection 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 interconnection structure impedance measurement circuit when the first and second switches are off and the third switch is on, or when the first and third switches are off and the second switch is on. The voltage detection module is connected to the first branch, the second branch, and the third branch, respectively, 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 third 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 interconnect structure impedance measurement circuit, to control the first switch, the second switch and the third switch to turn 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 interconnect structure and the impedance of 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 device for measuring interconnection structure impedance.

7. The first interconnection structure is an interconnection structure impedance measurement circuit in which at least two fifth resistors connected in parallel are equal in resistance value and the resistance value of the fifth resistors is equal to the resistance value of the second interconnection structure, or the first interconnection structure is an interconnection structure impedance measurement circuit in which a conductor is used. The constant current source is further configured to supply a second current, which is greater than the first current, to the interconnect structure impedance measurement circuit when the first switch is off and the second and third switches are on. The apparatus for measuring interconnection structure impedance according to claim 6.

8. A method for measuring the impedance of an interconnect structure, which is applied to the interconnect structure impedance measuring device described in claim 6, The steps include supplying a first current to the interconnection structure impedance measurement circuit, The interconnection structure impedance measurement circuit is controlled to a first state to detect a first voltage between the first branch and the second branch, and in the first state, the first switch and the second switch are turned off and the third switch is turned on. The interconnection structure impedance measurement circuit is controlled to switch from the first state to the second state to detect the second voltage between the first branch and the third branch, and in the second state, the first switch and the third switch are turned off and the second switch is turned on. The step includes stopping the supply of 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 resistance, the second resistance, the third resistance, the fourth resistance, the first voltage, the second voltage, and the first current. A method for measuring the impedance of interconnection structures.

9. A method for measuring the impedance of an interconnect structure, which is applied to the interconnect structure impedance measuring device described in claim 7, The steps include measuring the impedance of the second interconnection structure, The interconnection structure impedance measurement circuit is controlled to switch from a second state to a third state, and in the third state, the first switch is turned off and the second and third switches are turned on. The steps include providing a second current to the interconnect structure impedance measurement circuit within a predetermined period to increase current stress and accelerate the deterioration of the interconnect structure, The method includes the steps of measuring the impedance of the second interconnection structure, 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, The step of measuring the impedance of the second interconnection structure is: The steps include supplying a first current to the interconnection structure impedance measurement circuit, The interconnection structure impedance measurement circuit is controlled to a first state to detect a first voltage between the first branch and the second branch, and in the first state, the first switch and the second switch are turned off and the third switch is turned on. The interconnection structure impedance measurement circuit is controlled to switch from the first state to the second state to detect the second voltage between the first branch and the third branch, and in the second state, the first switch and the third switch are turned off and the second switch is turned on. A method for measuring the impedance of an interconnect structure, comprising the steps of: stopping the supply of 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 resistance, the second resistance, the third resistance, the fourth resistance, the first voltage, the second voltage, and the first current.

10. A step of recording the idle time from the start of supplying the second current to the end of measurement, The step further includes performing a reliability analysis on the second interconnection structure based on the aforementioned invalid time. The method according to claim 9.

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