Electromigration accelerated life test evaluation method and computer equipment

Abstract

The present invention discloses an electromigration accelerated life test evaluation method and computer equipment, the method comprising: determining multiple groups of accelerated life test conditions, the accelerated life test conditions comprising temperature, current density, and forward and reverse current time ratio; performing an accelerated life test of an interconnect structure based on the determined multiple groups of accelerated life test conditions, obtaining multiple groups of life data under accelerated life test conditions and temperature rise data of the interconnect structure; establishing a life prediction model based on the Black equation; fitting the current influence index, activation energy, and damage recovery coefficient based on the life data; substituting the obtained parameters into the life prediction model to obtain a complete life prediction model, and predicting the electromigration life of the interconnect structure under actual working conditions based on the complete life prediction model. The present invention can solve the problem that the existing electromigration performance evaluation mode does not match the actual application, and effectively support the screening, identification, and reliability evaluation of the interconnect structure.

Description

Technical Field

[0001] The invention belongs to the field of reliability evaluation of electronic components, and in particular relates to an electromigration accelerated life test evaluation method and computer equipment. Background Art

[0002] As electronic products continue to develop towards miniaturization and multifunctionality, the problem of interconnect electromigration in electronic packaging has become increasingly prominent and has become an important factor affecting product reliability and durability. The miniaturization of interconnect size has led to a significant increase in current density, which has accelerated the electromigration failure of the interconnect structure.

[0003] Existing electromigration accelerated life tests usually use constant DC current stress to conduct accelerated life tests to obtain life test data, and establish electromigration life evaluation models based on DC life test data. However, in the actual application of electronic components, there may often be a phenomenon of current working direction switching, so the existing electromigration performance evaluation model does not fully match the actual application. Summary of the invention

[0004] The purpose of the present invention is to provide an electromigration accelerated life test evaluation method, computer equipment, computer-readable storage medium and computer program product. By conducting an electromigration life acceleration test with bidirectional current stress, life test data of an interconnect structure under conditions closer to actual service conditions are obtained, and an electromigration life prediction model is established based on the life test data, thereby solving the problem of the mismatch between the existing electromigration performance evaluation model and the actual application, and effectively supporting the screening, identification and reliability evaluation of the interconnect structure.

[0005] One aspect of the present invention provides an electromigration accelerated life test evaluation method, comprising:

[0006] Step S1: determining multiple sets of accelerated life test conditions, wherein the accelerated life test conditions include temperature, current density, and forward and reverse current time ratios;

[0007] Step S2: performing an accelerated life test of the interconnect structure based on the determined multiple sets of accelerated life test conditions to obtain life data under the multiple sets of accelerated life test conditions and temperature rise data of the interconnect structure;

[0008] Step S3: Establish the following life prediction model based on Black equation:

[0009] ,

[0010] in, is the failure life data, A is a constant, n is the current influence index, Q is the activation energy, is the damage recovery coefficient, is the ambient temperature of the test loading, is the temperature rise caused by Joule heating of the current, is the Boltzmann constant, and are the current density values ​​when the current is in the forward and reverse directions, respectively. is the proportion of forward current time;

[0011] Step S4: Fitting different forward current time proportions and different temperature conditions based on the life data and The slope relationship of the current influence index is obtained; based on the life data, different current density conditions are fitted respectively. With 1 / The slope relationship of is obtained to obtain the activation energy; the damage recovery coefficient is obtained by solving the ratio of failure time under different forward current time ratio conditions;

[0012] Step S5: Substituting the obtained current influence index, activation energy and damage recovery coefficient into the life prediction model to obtain a complete life prediction model, and predicting the electromigration life of the interconnect structure under actual working conditions based on the complete life prediction model.

[0013] Preferably, in step S4, the damage recovery coefficient is obtained as follows:

[0014] ,

[0015] in, and They are the two proportions of forward current time, and They are the failure times under two conditions of forward current time ratio.

[0016] Preferably, in step S4, by performing weighted average processing on the obtained current influence index, activation energy and damage recovery coefficient, the mean values ​​of the current influence index, activation energy and damage recovery coefficient are obtained respectively;

[0017] In step S5, the obtained average values ​​of the current influence index, activation energy and damage recovery coefficient are substituted into the life prediction model to obtain the final life prediction model.

[0018] Preferably, in step S1, multiple groups of accelerated life test conditions are determined as follows: the current type and the operating frequency are consistent with the current type and the operating frequency carried by the interconnect structure when it is actually working; the test life time under the conditions of the highest temperature, the maximum current density and the largest proportion of the forward and reverse current time is not less than the preset time and the failure mechanism is electromigration failure; after determining the test conditions under the conditions of the highest temperature, the maximum current density and the largest proportion of the forward and reverse current time, the temperature, current density and forward and reverse current time proportion conditions are downgraded on this basis.

[0019] Preferably, at least three groups of temperature, three groups of current density, and three groups of forward and reverse current time ratios are determined to form a combination of test conditions.

[0020] Another aspect of the present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above method.

[0021] Another aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the above method when executed by a processor.

[0022] Another aspect of the present invention provides a computer program product, comprising a computer program, which implements the steps of the above method when executed by a processor.

[0023] According to the electromigration accelerated life test evaluation method, computer device, computer readable storage medium and computer program product of the above aspects of the present invention, by conducting an electromigration life acceleration test with bidirectional current stress, life test data of the interconnect structure under conditions closer to the actual service conditions are obtained, and an electromigration life prediction model is established based on the life test data, thereby solving the problem of mismatch between the existing electromigration performance evaluation model and the actual application, and effectively supporting the screening, identification and reliability evaluation of the interconnect structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0025] Figure 1 is a flow chart of an electromigration accelerated life test evaluation method according to an embodiment of the present invention;

[0026] Figure 2 It is a structural diagram of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Figure 1 FIG. 1 is a flow chart of an electromigration accelerated life test evaluation method according to an embodiment of the present invention. Figure 1 As shown, the electromigration accelerated life test evaluation method according to the embodiment of the present invention includes steps S1 to S5.

[0029] In step S1, multiple sets of accelerated life test conditions are determined. In one embodiment, the electromigration accelerated life test conditions are determined as follows:

[0030] (1) Based on the actual service working status of the evaluation objects such as electronic components, the current type and operating frequency of the accelerated life test of the interconnection structure are determined. The current type and operating frequency are required to be consistent with the current type and operating frequency carried by the interconnection structure when it is working.

[0031] (2) Explore the conditions for accelerated life testing, requiring that the test sample's test life time be no less than the preset time, such as 1 hour, when the temperature is the highest, the current density is the highest, and the proportion of forward and reverse current time is the largest.

[0032] (3) Perform a failure analysis on the interconnect life of the test samples under the conditions of the highest temperature, the largest current density, and the largest proportion of forward and reverse current time. It is required that the interconnect failure mechanism should be electromigration failure.

[0033] (4) After clarifying the test conditions with the highest temperature, the largest current density, and the largest proportion of the forward and reverse current time, the temperature, current density, and the proportion of the forward and reverse current time are set downgraded on this basis.

[0034] In this step, alternative test samples can be made for the interconnect structure that needs to be evaluated by electromigration accelerated life test. The interconnect structure design of the alternative test sample should be convenient for stress loading and test condition monitoring of the accelerated life test. The alternative test sample should have the same process, size, etc. as the actual object to be evaluated, and other parameters that may affect the life test results should also remain consistent.

[0035] In step S2, an accelerated life test of the interconnect structure is performed based on the determined multiple sets of accelerated life test conditions. Specifically:

[0036] (1) Based on the accelerated life test conditions obtained in step S1, an accelerated life test of the interconnect structure is performed, requiring at least three groups of temperature, three groups of current density, and three groups of forward and reverse current time ratio conditions to be coupled (at least 3*3*3=27 test conditions), wherein each group of test conditions has no less than 5 test samples.

[0037] (2) During the accelerated life test, relevant technical means are used to monitor the real-time changes in the resistance of the interconnection structure. The test life of the interconnection structure is determined based on the growth of the interconnection resistance (increase by a certain percentage, such as 10%, 20% or breakage, etc.), and relevant technical means are used to record the test life data.

[0038] (3) Evaluate the actual temperature rise of the interconnect structure under all accelerated life test conditions when subjected to high temperature and Joule heat coupling, using simulation or temperature testing techniques.

[0039] In step S3, the following life prediction model is established based on the Black equation:

[0040] (1)

[0041] in:

[0042] For failure life data, it is based on a preset life distribution model (common electromigration life distribution models include Weibull distribution, lognormal distribution, etc.). The system analyzes the life data (number of failures, failure probability, and life time) under different stress conditions to determine the predetermined quantile life of the sample.

[0043] A is the formula constant, n is the current influence index, Q is the activation energy, is the damage recovery coefficient, is the ambient temperature of the test loading, is the temperature rise caused by Joule heating of the current, is the Boltzmann constant. and are the current density values ​​when the current is in the forward and reverse directions, respectively. is the time proportion of the forward current, which can be expressed by the following formula:

[0044] / (2)

[0045] in, and They are respectively the action time of the forward current and the reverse current in a single current cycle.

[0046] In step S4, the parameters in the life prediction model are fitted based on the life data.

[0047] First, the current influence index n in the life prediction model is fitted:

[0048] Taking the logarithm of both sides of formula (1) yields:

[0049] (3)

[0050] in:

[0051] (4)

[0052] It can be seen that the current influence index n The negative value of and The slope of the relationship curve. Based on the experimental data, different current time ratios and different temperature conditions are fitted. and The slope relationship is weighted averaged to obtain the mean value of the current influence index. .

[0053] Secondly, the activation energy in the life prediction model Q Perform the fit:

[0054] Transforming formula (1) yields:

[0055] (5)

[0056] in:

[0057] (6)

[0058] When the current density is constant, and 1 / There is a linear relationship, and the slope is the activation energy value Q Based on the experimental data, the and 1 / The slope relationship of the activation energy value is weighted averaged to obtain .

[0059] Finally, the damage recovery coefficient in the life prediction model is Perform the fit:

[0060] Considering the ratio of failure time to forward current time, when the temperature T With current density j Under the same conditions, the two forward current time ratios are ( and ) failure time ( and ) to divide:

[0061] (7)

[0062] Further transformed into:

[0063] (8)

[0064] From formula (8), it can be concluded that the damage recovery coefficient can be obtained by solving the ratio of failure time under different forward current time ratio conditions: , weighted average processing of all calculated damage recovery coefficients is performed to obtain the mean value .

[0065] In step S5, all the relevant parameters obtained by fitting are substituted into the equation of formula (1) to obtain a complete life prediction model. Based on this model, the electromigration life of the interconnect structure under actual working conditions (under non-accelerated stress conditions) can be predicted.

[0066] According to the electromigration accelerated life test evaluation method of the above embodiment of the present invention, by carrying out bidirectional current stress electromigration life acceleration test, life test data of the interconnect structure under conditions closer to actual service conditions are obtained, and an electromigration life prediction model is established based on the life test data. The present invention can solve the problem that the existing electromigration performance evaluation model does not match the actual application, and provides a new set of solutions for the electromigration reliability evaluation of the interconnect structure. It has good engineering application value, can effectively support the screening, identification and reliability evaluation of the interconnect structure in high-end integrated circuits, and has huge economic and social benefits.

[0067] An embodiment of the present invention further provides a computer device, which may be a server, and its internal structure diagram may be as shown in FIG. Figure 2 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store operating parameter data of each framework. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps of the method of the embodiment of the present invention are implemented.

[0068] Those skilled in the art will understand that Figure 2The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0069] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed by a processor, the steps of the method of the embodiment of the present invention are implemented.

[0070] An embodiment of the present invention further provides a computer program product, including a computer program, which implements the steps of the method of the embodiment of the present invention when executed by a processor.

[0071] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An electromigration accelerated life test evaluation method, characterized in that: include: Step S1: determining multiple sets of accelerated life test conditions, wherein the accelerated life test conditions include temperature, current density, and forward and reverse current time ratios; Step S2: performing an accelerated life test of the interconnect structure based on the determined multiple sets of accelerated life test conditions to obtain life data under the multiple sets of accelerated life test conditions and temperature rise data of the interconnect structure; Step S3: Establish the following life prediction model based on Black equation: ， in, is the failure life data, A is a constant, n is the current influence index, Q is the activation energy, is the damage recovery coefficient, is the ambient temperature of the test loading, is the temperature rise caused by Joule heating of the current, is the Boltzmann constant, and are the current density values ​​when the current is in the forward and reverse directions, respectively. is the proportion of forward current time; Step S4: Fitting different forward current time proportions and different temperature conditions based on the life data and The slope relationship of the current influence index is obtained; based on the life data, different current density conditions are fitted respectively. and The slope relationship of is obtained to obtain the activation energy; the damage recovery coefficient is obtained by solving the ratio of failure time under different forward current time ratio conditions; Step S5: Substituting the obtained current influence index, activation energy and damage recovery coefficient into the life prediction model to obtain a complete life prediction model, and predicting the electromigration life of the interconnect structure under actual working conditions based on the complete life prediction model; In step S4, the damage recovery coefficient is obtained as follows: ， in, and They are the two proportions of forward current time, and They are the failure times under two conditions of forward current time ratio; In step S4, by performing weighted average processing on the obtained current influence index, activation energy and damage recovery coefficient, the mean values ​​of the current influence index, activation energy and damage recovery coefficient are obtained respectively; In step S5, the obtained average values ​​of the current influence index, activation energy and damage recovery coefficient are substituted into the life prediction model to obtain the final life prediction model.

2. The method according to claim 1, characterized in that In step S1, multiple groups of accelerated life test conditions are determined as follows: the current type and operating frequency are consistent with the current type and operating frequency carried by the interconnect structure during actual operation; the test life time under the conditions of highest temperature, maximum current density and maximum proportion of forward and reverse current time is not less than the preset time and the failure mechanism is electromigration failure; after determining the test conditions under the conditions of highest temperature, maximum current density and maximum proportion of forward and reverse current time, the temperature, current density and proportion of forward and reverse current time are respectively downgraded on this basis.

3. The method according to claim 2, characterized in that At least three groups of temperature, three groups of current density, and three groups of forward and reverse current time ratios are determined to form a combination of test conditions.

4. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 3.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

6. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 3 are implemented.

Images