JP2006313127A - System for evaluating soldered joint section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more rapidly predict the life of soldered joint sections. <P>SOLUTION: This system comprises a data storage part 11; an input control part 12; and a soldered joint evaluation part 13. A mathematical formula indicating the relation between values of factors related to the life of soldered joint sections and the life of the soldered joint sections in the case that repetitive loads due to temperature changes are exerted is previously stored in a design rule database 11 in a data storage part 11. In the system, the input control part 12 receives values of factors input via an input device 3 and related to the life of a soldered joint part to be examined connecting between an electronic part and a wiring board, between two electronic parts, or two boards. Then the soldered joint evaluation part 13 predicts the life of the soldered joint part to be examined connecting between the electronic part and the wiring board, between the two electronic parts, or the two boards on the basis of the mathematical formula and the values of the factors input by a user. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a system for predicting the life of a solder joint between electronic components.

  The life prediction of the solder connection portion is usually performed by performing an accelerated test such as a temperature cycle test and a high temperature and high humidity test on the test sample, and determining pass / fail based on the result. At the same time, by performing a simulation using a test sample or a model of an actual structure, the life prediction of the solder connection portion may be performed efficiently.

  A system described in Patent Document 1 is known as a system for predicting the life of a solder connection part by simulation. In this system, a stress-strain relationship is obtained from a mathematical expression (the sum of elastic strain, plastic strain, and viscous strain) that represents the total strain generated by a load by finite element analysis using a model. Based on the above, the fracture life and the remaining life with respect to the repeated load are calculated.

JP 2003-270060 A

  However, in the system described in Patent Document 1, since the total strain is represented by the sum of elastic strain, plastic strain, and viscous strain, as the model becomes more detailed, a considerable amount of time is required for calculation processing of the finite element analysis. . Moreover, in the system described in Patent Document 1, the interface reliability of the solder connection portion when a load due to an impact occurs is not taken into consideration.

  Then, an object of this invention is to provide the solder connection part evaluation system in which a user can estimate the thermal fatigue life of a solder connection part more rapidly. Another object of the present invention is to provide a solder connection evaluation system that can evaluate the interface reliability of a solder connection when a load due to an impact occurs.

According to the present invention,
Predict the lifetime of the evaluation target solder connection part of the structure in which any one of the connection between the electronic component and the wiring board, between the two electronic parts, or between the two boards is connected by the evaluation target solder connection part. A solder joint evaluation system
Storage means for storing data representing the relationship between the value of a factor related to the life of the solder joint and the life of the solder joint when a repeated load due to temperature change is given;
For the examination solder connection part, an input means for receiving an input of the factor value;
Based on the data stored in the storage unit and the value of the factor received by the input unit, a solder connection evaluation unit that calculates a predicted life of the examination solder connection unit;
A solder joint evaluation system is provided.

The present invention also provides:
The reliability of the evaluation object solder connection portion of the structure in which any one of the connection between the electronic component and the wiring board, between the two electronic components, and between the two substrates is connected by the evaluation object solder connection portion. A solder connection evaluation system for evaluating,
When the thickness of the intermetallic compound generated between the metallization of the wiring board or the electronic component and the solder forming the solder connection portion is calculated at the time of initial connection or temperature change, and a load due to impact occurs There is provided a solder connection evaluation system comprising solder connection evaluation means for evaluating the reliability of the solder connection based on the thickness of the intermetallic compound layer.

  According to the present invention, the life of the solder connection portion can be predicted more quickly. Further, it is possible to evaluate the interface reliability of the solder connection portion when a load due to impact occurs.

  Hereinafter, an embodiment according to the present invention will be described with reference to the accompanying drawings.

  First, the overall configuration of the solder joint life prediction system according to the present embodiment will be described with reference to FIG.

  The solder joint life prediction system includes an information processing device 1, an external device (an output device 2 such as a display, and an input device 3 such as a keyboard) connected to the information processing device 1.

  Here, the information processing device 1 executes a normal hardware configuration as a computer capable of executing a program in accordance with an instruction from the outside (a hard disk storing a program and data, a memory, and a program loaded from the hard disk to the memory). CPU, an interface to which an external device is connected, and the like. And this information processing apparatus is an electronic device (between an electronic component and a wiring board, between two electronic components, and between two boards by executing a predetermined program on such a hardware configuration. The following functional configuration for predicting the life (thermal fatigue life) of the solder connection portion subjected to thermal fatigue and the interface reliability of the solder connection portion is realized.

  The information processing apparatus 1 includes a data storage unit 11 in which data necessary for predicting the thermal fatigue life and interface reliability of the solder connection portion, and input control for receiving input data (data from the input device 3) from the user. Unit 12, solder connection evaluation unit 13 that predicts the thermal fatigue life of the solder connection unit based on input data (connection structure, connection conditions, required reliability, etc.) from the user and information stored in the data storage unit 11, solder connection evaluation unit The calculation results of the data import unit 14 and the solder connection evaluation unit 13 that pass the CAD data to 13 (the reliability determination results for thermal fatigue failure and impact failure, and guidelines for obtaining a structure with a longer life) are output to the output device 2. The output control unit 15 is realized.

  The data storage unit 11 stores two types of databases 111 and 112 in advance. Further, the data storage unit 11 may store CAD data 113 used in a CAD analysis process described later.

  Of the two types of databases, one database (material database) 111 has a component name or material for each component or material (printed circuit board, ceramic substrate, silicon chip, metallized material, solder material, etc.) constituting the electronic device. Name and material property value data required for structural analysis are registered. Further, in the material database 111, solder thermal fatigue strength data and interface fracture mode data representing the interface fracture mode are registered.

  The material property value data includes, for example, longitudinal elastic modulus, linear expansion coefficient, Poisson's ratio, yield stress, work hardening coefficient, diffusion constant, activation energy, and the like. In addition, the material property value data may include temperature-dependent data.

  The interfacial fracture mode data includes reflow conditions (holding time, holding temperature) and interfacial fracture strength values obtained by drop tests or shear tests of samples created under the reflow conditions. This interface fracture mode data is used in interface reliability prediction processing and reflow profile optimization processing described later.

  In the other database (design rule database) 112, basic model data in which constrained points are determined in advance, life cycle Cb obtained in the experiment, S / N ratio of the structure used in the experiment, and various values obtained through the experiment. Formulas (such as solder thermal fatigue life prediction formulas and interface reliability prediction formulas) are stored.

Further, among the plurality of basic model data, for example, four types of basic model data representing a model of a general structure including a solder joint as shown in FIG. 2 are included. The four types of basic model data given here represent models having the following structure.
Type 1 structure: A wiring board or electronic component (package component or the like) 20 is mounted on the wiring substrate 22, and the electronic component 20 and the substrate 22 are connected by a plurality of solder connection portions 21.
Type 2 structure: The solder connection portion 21 in the type 1 structure is sealed with a resin 23.
Type 3 structure: A wiring board or electronic component 20 is mounted on a wiring board 22. The electronic components 20 and the like and the substrate 22 are connected by a plurality of solder connection portions 21. An electronic component (chip, package, etc.) 24 is mounted on the electronic component 20 or the like, and the electronic component 24 and the electronic component 20 or the like are connected by solder 25.
Type 4 structure: The solder connection portion 21 in the type 3 structure is sealed with a resin 23.

  In the simple analysis process and the detailed analysis process described later, the user selects, from among these basic models, a model of a structure whose thermal fatigue life should be examined or a model of a structure that approximates the structure as a model to be examined. Note that the structure shown in FIG. 2 is an example, and it is not always necessary to store model data representing a model of this structure in the data storage unit 11 as basic model data.

  Next, solder joint life prediction processing executed in the solder joint life prediction system according to the present embodiment will be described. Here, the solder joint life prediction process is classified into the following three types of analysis processes suitable for each stage from the initial stage to the final stage of design.

(1) Simplified analysis process At the initial stage of design, it is necessary to narrow down a more appropriate solder connection structure from a large number of solder connection structures. For this reason, the user needs to grasp the tendency of reliability of a plurality of solder connection structures in a short time. In such a case, a simple analysis process that can easily and quickly derive the reliability of a plurality of solder connection structures is used without performing calculations by the finite element method.

(2) Detailed analysis processing At a stage where the solder connection structures are narrowed down to some extent, the ranking of the plurality of solder connection structures obtained by narrowing down is performed. In order to perform such ranking, the user needs to accurately grasp the thermal fatigue life of a plurality of solder connection portions obtained by narrowing down. In such a case, a detailed analysis process capable of accurately predicting the life of a plurality of solder joints is used.

(3) CAD analysis processing At the final stage of design, the user needs to grasp the accurate thermal fatigue life of the solder joint applied to the actual product. In such a case, a CAD analysis process that can accurately predict the thermal fatigue life of the solder joint having a shape applied to an actual product is used.

  Hereinafter, each of these three types of analysis processing will be described. Here, it is assumed that a predetermined program is already started on the information processing apparatus 1 and the above-described functional configuration is realized.

(1) Simple analysis process FIG. 3 shows a flowchart of the simple analysis process.

  When the user uses the input device 3 to instruct any one of the models represented by the plurality of basic model data (for example, the model in FIG. 2) as a model to be examined (F1), the solder connection evaluation unit 13 Requests the input of the dimensions of the model to be examined through the output control unit 15. Here, the user uses the input device 3 to measure dimensions necessary for analysis of the model to be examined, such as board dimensions (vertical dimensions × horizontal dimensions), board thickness, solder ball diameter, bump pitch, and the like. When the values are input, the input control unit 12 gives the dimension values to the solder connection evaluation unit 13 (F2).

  Thereafter, in response to an instruction from the solder connection evaluation unit 13, the output control unit 15 causes the output device 2 to display a list of registered parts and the like in the material database 111. When the user selects a part or material to be used for the model to be examined from the list, the solder connection evaluation unit 13 reads out material property value data of the part or the like selected from the list from the material database 111. The material property value data is held as material property value data of parts and the like included in the model to be examined. However, when a new part not registered in the material database 111 is used as a part included in the model to be examined, the user inputs the name of the part and the material property value data using the input device 3. do it. At this time, the solder connection evaluation unit 13 holds the input material property value data as the material property value data of the parts and the like included in the model to be examined, and uses the input name in order to use in subsequent calculations. Are registered in the material database 111 in association with each other.

  Next, the solder connection evaluation unit 13 inputs the boundary condition (restraint location, temperature history, etc.) and the temperature condition (temperature cycle conditions defined by the maximum temperature, the minimum temperature, and the holding time), and the output control unit 15 To request through. Here, in the case where a constraint location is determined in advance in the basic model data, the user does not need to input a constraint condition as a boundary condition.

  In response to this, the user inputs appropriate data (F3), and when input of data necessary for the following analysis is completed, the solder connection evaluation unit 13 does not use the finite element method and is included in the model to be examined. Calculate the thermal fatigue life of the solder joint. Specifically, it is as follows.

  Here, as an example, the Taguchi method is used to obtain the relationship between the dimensions and material properties of each member and the thermal fatigue life.

  First, the value of a factor that may affect the thermal fatigue life of the solder joint is extracted from user input data. For example, as such factors, substrate dimensions (longitudinal dimensions × lateral dimensions), substrate thickness dimensions, substrate longitudinal elastic modulus, substrate linear expansion coefficient, solder longitudinal elastic modulus, solder linear expansion coefficient, solder Height, solder pitch, chip size (vertical dimension × horizontal dimension), chip thickness, and the like. These are examples of factors that may affect the thermal fatigue life of the solder joint, and when other factors are present, those factors may be added.

First, the solder connection evaluation unit 13 calculates the S / N ratio for each factor for each solder connection portion of the model to be studied (η _k = f _k (x _k ): k = 1 to n). Are read from the design rule database 112, and the S / N ratio is obtained from those mathematical formulas and the values of the factors (x _k : k = 1 to n). For example, when paying attention to the solder joint at the most corner and the solder joint adjacent thereto, two types of S / N ratios (η _{1 to} η _n ) are required.

The calculation formula (η _k = f _k (x _k ): k = 1 to n) of the S / N ratio used here is _obtained for each basic model as follows, and the design rule database 112 is used as follows. Is stored in advance.

An appropriate range of levels is determined for each factor (x _k : k = 1-n) and each factor and level is assigned to an L18 or L36 orthogonal table. Data analysis under each condition using this orthogonal table may be performed by simulation or based on experiments. As a result of the data analysis, mathematical formulas (η _k = f _k (x): k = 1 to n) for calculating the S / N ratio are obtained for each factor. These mathematical expressions represent a factor effect diagram showing the relationship between the S / N ratio and the factor value as shown in FIG.

In order to obtain the S / N ratio η _new of the new structure defined by the user input data, the solder connection evaluation unit 13 uses the following equation to calculate the S / N ratio at each point of interest (here, N). η _newj (j = 1 to N) is calculated.

これにより、Ｎ個のη_new１〜η_newＮが得られたら、はんだ接続評価部１３は、これらのなかから最小値を抽出し、この最小値を新規構造のＳ／Ｎ比η_newとする（Ｆ４）。すなわち、Ｎ個の着目点のうち、最も寿命の短い箇所を抽出し、その箇所のＳ／Ｎ比を新規構造のＳ／Ｎ比η_newとする。

Thus, when the N number of _{η new1} ~η newN obtained, solder connection evaluation unit 13 extracts the minimum value from among these, is the minimum value and the S / N ratio eta _{new new} new structure (F4 ). That is, of the N points of interest, the part with the shortest lifetime is extracted, and the S / N ratio at that part is set as the S / N ratio η _new of the new structure.

Thereafter, the solder connection evaluation unit 13 reads the life cycle Cb and the S / N ratio ηb obtained by the experiment from the data storage unit 11, and from the life Cb and the S / N ratio η _new of the new structure, The estimated life C _new is calculated as follows (F5).

η _new −ηb = −10 log (σ _new ) ² +10 log (σb) ²
= 20log (σb / σ _new )
α = 10 ^{(ηnew−ηb) / 20}
However, α = σb / σ _new
C _new = αCb
After calculating the estimated life C _new of the new structure in this way, the solder connection evaluation unit 13 requests the user to input the target life via the output control unit 15 (F6). Here, the input of the target life is requested after calculation of the estimated life of the solder connection portion, but may be requested before calculation of the estimated life of the solder connection portion.

Solder connecting evaluation unit 13 compares the estimated lifetime C _new and the target lifetime of the new structure, estimated lifetime C _new novel structure determines whether or not exceeds the target lifetime (F7).

As a result, when the estimated life C _new of the new structure exceeds the target life, the solder connection evaluation unit 13 determines that the new structure defined by the user input data is acceptable, and to that effect, The data is output via the output control unit 15.

On the other hand, when the estimated lifetime C _new of the new structure is less than or equal to the target lifetime, the solder connection evaluation unit 13 determines that the new structure is unacceptable and makes the structure satisfy the target lifetime. The pointer is presented via the output control unit 15. For example, how to change the value of each factor in order to bring the lifetime of the new structure closer to the target lifetime is obtained from the mathematical expression representing the relationship shown in the factor effect diagram of FIG. (F11).

  When the user selects the model to be examined and the material again based on this guideline, the same processing as described above is executed under new conditions. Thereby, the structure with the longest lifetime can be finally obtained. When the user reselects the material, there may be a function of selecting a factor that cannot be changed in terms of structure or design.

  According to such a simple analysis process, since the finite element method which requires a lot of time is not used, the life of the solder connection portion can be predicted in a short time. Moreover, since a guideline for extending the life of the solder connection portion is presented, even a user who does not have knowledge about the life prediction of the solder connection can easily obtain a structure that satisfies the target life. it can. Therefore, the development period can be shortened.

  In the present embodiment, data is set in the order of material property value data, boundary conditions, and temperature conditions, but it is not always necessary to set data in this order. For example, the temperature condition may be set before the material property value data.

In this embodiment, the Taguchi method is used, but an experiment design method may be used.
(2) Detailed Analysis Processing FIG. 5 shows a flowchart of the detailed analysis processing.

  As in the case of the simple analysis process, the user designates one of the models represented by a plurality of basic model data (for example, the model shown in FIG. 2) as a model to be examined (F21), and further studies. Dimension of target model, material physical property values (longitudinal elastic modulus, linear expansion coefficient, Poisson's ratio, yield stress, work hardening coefficient, etc.), boundary conditions (restraint location, temperature history, etc.) and temperature conditions (maximum temperature) , Temperature cycle conditions defined by minimum temperature and holding time) (F22 to F23). In the case where a constraint location is previously defined in the basic model data, the user does not need to input a constraint condition as a boundary condition, as in the case of the simple analysis process. The material property value data may be shared with the simple analysis process and the CAD analysis process.

  Next, the solder connection evaluation unit 13 calculates the estimated life as follows.

  Here, since it is necessary to derive the estimated life more accurately than the simple analysis process, the solder connection evaluation unit 13 creates a model using input data from the user, and further performs mesh division of the model. When the existence of a bump portion that is likely to break is predicted, the vicinity of the bump is modeled in more detail and the mesh is divided in more detail. Using this model, the distortion amplitude is calculated by software of the finite element method (F24). Note that the processing using the finite element method may be performed by the information processing apparatus 1 or a large computer or the like.

  The solder connection evaluation unit 13 calculates the estimated life from the strain amplitude calculated by the finite element method using a mathematical expression (solder connection life prediction formula) representing the relationship between the strain amplitude and the life cycle (F25).

  The mathematical formula used here is obtained as follows and is stored in the design rule database 112 in advance.

  A temperature cycle test is performed on a test sample having an arbitrary shape including the solder connection portion, and a crack progress state in the solder connection portion is observed every appropriate number of temperature cycles. And the crack length which generate | occur | produces in a solder connection part with a temperature change is measured, and the fracture life of a solder connection part is estimated based on this crack length. On the other hand, a simulation is performed on the same shape as that of the test sample to calculate the distortion amplitude or distortion (see FIG. 6) at the crack occurrence location. As described above, correspondence data between the fracture life obtained by the temperature cycle test and the strain amplitude or strain obtained by the simulation is obtained. By obtaining a plurality of such correspondence data, a solder life prediction curve as shown in FIG. 7 is obtained. By formulating this solder life prediction curve, a solder connection life prediction formula can be obtained. Since this solder connection life prediction formula is created based on sample data, the strain includes creep strain.

  By using such a solder connection life prediction formula, it is possible to calculate the estimated life by simply obtaining the strain amplitude or strain by simulation without creating a sample of a new structure.

  Thereafter, as in the case of the simple analysis process, the solder connection evaluating unit 13 receives an input of the target life from the user (F26), and the estimated life exceeds the target life by comparing the target life with the estimated life. It is determined whether or not (F27).

  As a result, when the estimated life exceeds the target life, the solder connection evaluation unit 13 outputs that the new structure defined by the user input data is acceptable, as in the case of the simple analysis processing.

  On the other hand, when the estimated life is less than or equal to the target life, the solder connection evaluation unit 13 indicates a guideline for making the structure satisfying the target life (as shown in the factor effect diagram of FIG. 4 as with the simple analysis process). A guideline obtained from a mathematical expression representing the relationship) is presented via the output control unit 15 (F28). When the user selects the model and material to be examined again based on this guideline, the same calculation process is executed again under new conditions. Thereby, finally, a structure satisfying the target life can be obtained. When the user reselects the material, there may be a function of selecting a factor that cannot be changed in terms of structure or design.

According to such a detailed analysis process, since the finite element method is used, the life of the solder connection portion can be calculated with higher accuracy.
(3) CAD Analysis Process FIG. 8 shows a flowchart of the CAD analysis process.

  When one or more design data (CAD data) created separately by the user is stored in, for example, the data storage unit 11, the data import unit 14 imports the CAD data designated by the user and passes it to the solder connection evaluation unit 13. (F101).

  After that, the user is stipulated by the setting of material property value data of each member etc. included in the structure represented by the CAD data, boundary conditions (constraint conditions, temperature history, etc.) and temperature conditions (maximum temperature, minimum temperature, holding time, etc. Temperature cycle conditions) (F102, F103). The material property value data can be set by selecting from a list of registered parts in the material database 111 or inputting a new numerical value, as in the simple analysis process and the detailed analysis process.

  Thereafter, the solder connection evaluation unit 13 calculates the estimated life as follows using a finite element method or the like in order to calculate the life with high accuracy.

  The solder connection evaluation unit 13 performs mesh division on the CAD data. This mesh division may be performed by a mesh division program, or the user may specify a mesh.

  Thereafter, the solder connection evaluation unit 13 uses, for example, a new structure represented by the CAD data by arithmetic processing (F24 to F25) using a mathematical expression representing the relationship between the strain amplitude or the strain and the life cycle, as in the case of the detailed analysis processing. Is calculated (F104 to F105), and it is determined whether or not the estimated life satisfies the target life input by the user (F106 to F107).

  As a result, when the estimated life exceeds the target life, the solder connection evaluation unit 13 outputs via the output control unit 15 that the new structure is acceptable as in the case of the detailed analysis processing.

  On the other hand, when the estimated life is less than or equal to the target life, the solder connection evaluation unit 13 provides a guideline for making a structure satisfying the target life by the same processing as in the detailed analysis processing. (F108). Here, if the user selects the model to be examined and the material again based on this guideline, the same calculation process is executed again under new conditions.

  According to such CAD analysis processing, the thermal fatigue life of the structure having a shape other than the basic model prepared in advance, that is, the structure represented by the CAD data created by the user is accurately calculated using the finite element method. can do.

  By the way, the main failure modes of the solder connection part include not only thermal fatigue failure but also interface failure caused by growth of intermetallic compounds between the pad and the solder, which occurs when an impact is applied due to dropping or the like. . The solder connection evaluation system according to the present embodiment can also predict such interface reliability. Hereinafter, the interface reliability prediction process will be described with reference to FIG.

  The interface fracture of the solder joint is roughly divided into two modes. In one mode (first mode), the interface between the solder and the metallization is formed by the thick growth of the intermetallic compound formed by the reaction between the solder and the metallization of the pad portion during reflow or temperature cycling. The impact resistance of the is reduced. In the other mode (second mode), such a compound grows and all of the metallization reacts with the solder, so that the impact resistance at the interface between the metallization and the solder is lowered. In the following, the reliability of the solder joints against interface failure in both modes is predicted.

  When the user selects or inputs a solder material and a metallized material using the input device 3 and further inputs an initial thickness of the metallization (S1), the solder connection evaluation unit 13 selects the solder material and the metallized material selected by the user. Material property value data (here, for example, diffusion constant, activation energy, etc.) is read from the material database 111. In addition, when using a new material as a solder material and a metallizing material, the user should just input the name and material property-value data of those materials. At this time, the solder connection evaluation unit 13 registers the input material property value data in the material database 111 in association with the input name in order to use it in the subsequent calculation.

  Thereafter, the user uses the input device 3 to input a reflow profile and a temperature cycle condition having a configuration capable of handling several types of profiles and repeated reflow (S2). For example, the reflow profile includes a maximum temperature, a melting time, and the like, and the temperature cycle condition includes a maximum temperature, a minimum temperature, a holding time, and the like. The life prediction system may be able to cope with optimization of the reflow profile, which will be described later.

  The solder connection evaluation unit 13 evaluates the interface reliability related to the compound growth thickness and the interface reliability related to the remaining metallization thickness based on the user input data as follows.

  The solder connection evaluation unit 13 calculates either the sum of the heat addition by reflow and the heat addition by the temperature cycle, or one of these heat additions (S3). Furthermore, the solder connection evaluation unit 13 calculates the growth thickness of the grown compound based on the holding time and the holding temperature (S4).

  Further, the solder connection evaluation unit 13 calculates the metallized consumption thickness from the growth thickness of the compound (S5), and calculates the remaining metallized thickness by comparing the metallized consumption thickness with the initial metallized thickness (S6). .

  Thereafter, the solder connection evaluation unit 13 determines the acceptability of the interface reliability related to the remaining metallization thickness based on the presence or absence of the remaining metallization, which is known from the remaining metallization thickness obtained in S6. Moreover, the solder connection evaluation part 13 determines the pass / fail of the interface reliability regarding a compound growth thickness by comparing the interface fracture mode data of the material database 111, and the heat addition value calculated | required by S3 (S7). Thereafter, the solder connection evaluation unit 13 displays the interface reliability evaluation result and the compound growth thickness on the output device 2 via the output control unit 15. Thereafter, improvement guidelines are presented as necessary (S8). For example, compare the thickness of the compound that grows due to temperature changes in the actual environment or test environment with the initial pad thickness, present the required initial pad thickness, or use the appropriate reflow conditions obtained by the reflow profile optimization process described below. May be presented.

  Finally, the reflow profile optimization process will be described.

  For the structure input by the user, the interface fracture strength is determined based on the interface fracture strength data registered in the material database 111. Then, a reflow condition that does not decrease the interface fracture strength is extracted and presented.

  According to the present invention, an analysis system for predicting the life of a solder connection part of a structure in which a substrate having electronic components and wiring or a plurality of electronic components are connected by solder is used to calculate the connection life when a temperature change or impact occurs. It has a function of deriving and displaying, and it is possible to present a pass / fail judgment and a longer life guideline based on data accumulated in advance.

It is a schematic block diagram of the solder connection part evaluation system which concerns on one Embodiment of this invention. It is the figure which showed the structural example of the model which the basic model data which concern on one Embodiment of this invention represents. It is a flowchart of the simple analysis process which concerns on one Embodiment of this invention. It is the figure which showed the example of the factor effect figure which concerns on one Embodiment of this invention. It is a flowchart of the detailed analysis process which concerns on one Embodiment of this invention. It is a related figure of stress and distortion or distortion amplitude concerning one embodiment of the present invention. It is the figure which showed the example of the lifetime prediction curve which concerns on one Embodiment of this invention. It is a flowchart of the CAD analysis process which concerns on one Embodiment of this invention. It is a flowchart of the interface reliability prediction process which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Information processing apparatus, 2 ... Output device, 3 ... Input device, 11 ... Data storage part, 12 ... Input control part, 13 ... Solder connection evaluation part, 14 ... Data import part, 15 ... Output control part, 111 ... Material Database, 112 ... Design rule database

Claims (9)

Predict the lifetime of the evaluation target solder connection part of the structure in which any one of the connection between the electronic component and the wiring board, between the two electronic parts, or between the two boards is connected by the evaluation target solder connection part. A solder joint evaluation system
Storage means for storing data representing the relationship between the value of a factor related to the life of the solder joint and the life of the solder joint when a repeated load due to temperature change is given;
For the examination solder connection part, an input means for receiving an input of the factor value;
Based on the data stored in the storage unit and the value of the factor received by the input unit, a solder connection evaluation unit that calculates a predicted life of the examination solder connection unit;
A solder joint evaluation system comprising: The solder connection evaluation system according to claim 1,
Having an output means,
The solder connection evaluation means
Based on the data stored in the storage means, a guide for extending the life longer than the predicted life is output from the output means. The solder connection evaluation system according to claim 1 or 2,
The solder connection evaluation system, wherein the data stored in the storage means is data derived by a Taguchi method or an experimental design method. The solder joint evaluation system according to any one of claims 1, 2, and 3,
The solder connection evaluation means can calculate a predicted life of the solder connection portion to be examined by the first analysis process or the second analysis process,
In the first analysis process, the solder connection evaluation means calculates a predicted life of the solder connection portion to be examined based on the data and the value of the factor,
In the second analysis process, the solder connection evaluation means calculates a predicted life of the evaluation object solder connection part by a finite element method when a repeated load due to a temperature change occurs.
A solder joint evaluation system characterized by that. The solder joint evaluation system according to claim 4,
The solder connection evaluation means can further calculate a predicted life of the examination solder connection portion by a third analysis process,
In the third analysis process, the input means accepts input of structure data and material data of the structure, and boundary conditions, and the solder connection evaluation means is based on the structure data, the material data, and the boundary conditions. Generate a model, and calculate the predicted life of the solder connection portion to be evaluated when a repeated load due to a temperature change occurs, by a finite element method using the model,
A solder joint evaluation system characterized by that. The solder connection evaluation system according to claim 4 or 5,
Having storage means for storing information representing the relationship between the strain or strain amplitude of the solder joint and the life,
In the second and third evaluation processes, the solder connection evaluation means calculates distortion or distortion amplitude of the evaluation target solder connection portion, and based on the calculation result and information stored in the storage means, A solder joint evaluation system, characterized by calculating a predicted life of a solder joint to be evaluated. The reliability of the evaluation object solder connection portion of the structure in which any one of the connection between the electronic component and the wiring board, between the two electronic components, and between the two substrates is connected by the evaluation object solder connection portion. A solder connection evaluation system for evaluating,
When the thickness of the intermetallic compound generated between the metallization of the wiring board or the electronic component and the solder forming the solder connection portion is calculated at the time of initial connection or temperature change, and a load due to impact occurs A solder connection evaluation system comprising: solder connection evaluation means for evaluating the reliability of the solder connection based on the thickness of the intermetallic compound layer. The solder joint evaluation system according to claim 7,
Comprising output means,
The solder connection evaluation means obtains the thickness of the metallization necessary for the wiring board or the electronic component based on the calculated thickness of the intermetallic compound layer and the initial thickness of the metallization, and outputs the output to the output means.
A system characterized by that. The lifetime of the evaluation object solder connection part of the structure in which any one of the connection between the electronic component and the wiring board, between the two electronic components, and between the two boards is connected by the evaluation object solder connection part, A solder joint evaluation method predicted by an information processing device,
The information processing apparatus includes:
Storage means for storing data representing the relationship between the value of a factor related to the life of the solder joint and the life of the solder joint when a repeated load due to temperature change is given;
Input means;
Solder connection evaluation means;
With
The solder joint evaluation method is as follows:
The input means receives the input of the factor value for the examination solder connection portion;
The solder connection evaluation means calculates a predicted life of the examination solder connection portion based on the data stored in the storage means and the value of the factor received by the input means;
A method for evaluating a solder joint, comprising:

Images