Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1643948
Y. Liu, Yumin Liu, S. Irving, T. Luk, D. Desbiens, Zhen Zhang, Z. Suo
This paper will focus on reliability study of interconnect structure for two areas. The first area is reliability of interconnect structure in thermal cycling test. Major work includes the fundamental study of ratcheting for passivation cracking. By combination with the upper limit of stress intensity factor for a finite crack in the passivation and the ratcheting failure mechanism, the life of passivation in thermal cycling can be obtained in terms of the lower bound of critical number of cycles of the crack initiation. The passivation crack criterion is established to identify the failure modes: no cracking and delayed cracking. Another area is the reliability of bond paid over active (BPOA) with copper bond pads. Major work includes stress analysis of the dielectric layer under probing with different parameters such as the thickness of the copper bond pad, dielectric, metallization and the passivation under different probing loads. The elastic plastic model in copper bond pad and metal lines are introduced. Finally comparison of the results between copper bond pad and aluminum bond pad will be presented
{"title":"Reliability Study of Interconnect Structures in IC Packages","authors":"Y. Liu, Yumin Liu, S. Irving, T. Luk, D. Desbiens, Zhen Zhang, Z. Suo","doi":"10.1109/ESIME.2006.1643948","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1643948","url":null,"abstract":"This paper will focus on reliability study of interconnect structure for two areas. The first area is reliability of interconnect structure in thermal cycling test. Major work includes the fundamental study of ratcheting for passivation cracking. By combination with the upper limit of stress intensity factor for a finite crack in the passivation and the ratcheting failure mechanism, the life of passivation in thermal cycling can be obtained in terms of the lower bound of critical number of cycles of the crack initiation. The passivation crack criterion is established to identify the failure modes: no cracking and delayed cracking. Another area is the reliability of bond paid over active (BPOA) with copper bond pads. Major work includes stress analysis of the dielectric layer under probing with different parameters such as the thickness of the copper bond pad, dielectric, metallization and the passivation under different probing loads. The elastic plastic model in copper bond pad and metal lines are introduced. Finally comparison of the results between copper bond pad and aluminum bond pad will be presented","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"1 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89744190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1643968
C. Chiu, Chung-Jung Wu, C. Peng, C. Chou, K. Chiang, T. Ku, K. Cheng
Since today's trend is toward `green' products, manufacturers are moving toward lead-free schemes. The flip chip package, which has been widely utilized in high-performance products, also faces this challenge. In addition, the underfill material in the flip chip package has a specific characteristic, glass transition (Tg) temperature, and the properties of the underfill material changes drastically when it experiences temperature difference containing its Tg. With a highly temperature-dependent feature, the underfill may have an impact on the reliability of the packaging. A methodology combining the verified finite element method and factorial analysis is established to estimate this effect in this study. In factorial analysis, the CTE and Young's modulus of the underfill at temperatures above and below its T g are selected. In addition to the four above mentioned factors, the Tg temperature of the underfill is also chosen as a design factor. As for the response, die cracking is a concerned failure mode to the lead-free flip chip package, and hence the first principal stress is chosen as the response in factorial analysis. Aside from these, the solder fatigue life is also discussed. This study reveals that the Tg temperature is the most sensitive factor to the reliability of both die cracking and solder fatigue life. However, the lead-free flip chip package using the underfill material with a higher Tg temperature has a better solder fatigue life but has the larger stress which may likely lead to the die crack
{"title":"The Reliability Impact of Highly Temperature-Dependent Underfill Material to the Lead-Free Flip Chip Package","authors":"C. Chiu, Chung-Jung Wu, C. Peng, C. Chou, K. Chiang, T. Ku, K. Cheng","doi":"10.1109/ESIME.2006.1643968","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1643968","url":null,"abstract":"Since today's trend is toward `green' products, manufacturers are moving toward lead-free schemes. The flip chip package, which has been widely utilized in high-performance products, also faces this challenge. In addition, the underfill material in the flip chip package has a specific characteristic, glass transition (Tg) temperature, and the properties of the underfill material changes drastically when it experiences temperature difference containing its Tg. With a highly temperature-dependent feature, the underfill may have an impact on the reliability of the packaging. A methodology combining the verified finite element method and factorial analysis is established to estimate this effect in this study. In factorial analysis, the CTE and Young's modulus of the underfill at temperatures above and below its T g are selected. In addition to the four above mentioned factors, the Tg temperature of the underfill is also chosen as a design factor. As for the response, die cracking is a concerned failure mode to the lead-free flip chip package, and hence the first principal stress is chosen as the response in factorial analysis. Aside from these, the solder fatigue life is also discussed. This study reveals that the Tg temperature is the most sensitive factor to the reliability of both die cracking and solder fatigue life. However, the lead-free flip chip package using the underfill material with a higher Tg temperature has a better solder fatigue life but has the larger stress which may likely lead to the die crack","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"12 1","pages":"1-8"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81364509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1644023
E. Bonnaud, P. Gudmundson
Mechanical behaviour of lead-free solder has been investigated experimentally and thereafter modelled analytically. Material test specimens subjected to uniaxial cyclic loadings at different strain rates exhibit noticeable properties: viscoplasticity, nonlinear mixed hardening within each cycle and hardening followed by softening between consecutive cycles. To accurately describe these behaviours, a modified Armstrong and Fredrick model was combined to the Perzyna viscoplastic evolution equation. The set of parameters was determined by both curve-fitting and use of analytical relations
{"title":"Lead-Free Solder Cyclic Plasticity Characterization for Drop Test Simulations","authors":"E. Bonnaud, P. Gudmundson","doi":"10.1109/ESIME.2006.1644023","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1644023","url":null,"abstract":"Mechanical behaviour of lead-free solder has been investigated experimentally and thereafter modelled analytically. Material test specimens subjected to uniaxial cyclic loadings at different strain rates exhibit noticeable properties: viscoplasticity, nonlinear mixed hardening within each cycle and hardening followed by softening between consecutive cycles. To accurately describe these behaviours, a modified Armstrong and Fredrick model was combined to the Perzyna viscoplastic evolution equation. The set of parameters was determined by both curve-fitting and use of analytical relations","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"20 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76873370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1643991
S. Abu-Salih, D. Elata
In this work, a new test structure and method for measuring residual stress is presented. The test structure is a single clamped-clamped beam with electrodes symmetrically positioned along both sides of the beam. The electromechanical buckling response is used to measure the residual stress. It is shown that a single test structure of the proposed design may be used to measure both compressive and tensile residual stresses in a continuous wide range
{"title":"Using ElectroMechanical Buckling for Measuring Residual Stress","authors":"S. Abu-Salih, D. Elata","doi":"10.1109/ESIME.2006.1643991","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1643991","url":null,"abstract":"In this work, a new test structure and method for measuring residual stress is presented. The test structure is a single clamped-clamped beam with electrodes symmetrically positioned along both sides of the beam. The electromechanical buckling response is used to measure the residual stress. It is shown that a single test structure of the proposed design may be used to measure both compressive and tensile residual stresses in a continuous wide range","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"18 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84409626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1644039
V. Burg, J. den Toonder, A. van Dijken, J. Hoefnagels, M. Geers
A method for the characterization of mechanical properties of freestanding thin metal film materials used in RF-MEMS is evaluated. Freestanding beam structures are manufactured from a sputtered layer of AlCu(1wt%) on top of a wafer using an industrialized RF-MEMS manufacturing process. The methods of examining micro structure and geometry are studied. It is shown that these methods are promising for extracting the desired information about the material. Simple bending experiments are carried out on micro-scale beams of varying length and thickness using an indenter device. Elastic material properties are extracted from the results, using finite element technology combined with elastic theory, removing the necessity of extensive finite element simulations. It is shown that the beam length and indenter positioning play a crucial role. The obtained results show agreement with expected values for longer beams, but no obvious relation with the film thickness is found within the experimental range addressed
{"title":"Characterization Method for Mechanical Properties of Thin Freestanding Metal Films for RF-MEMS","authors":"V. Burg, J. den Toonder, A. van Dijken, J. Hoefnagels, M. Geers","doi":"10.1109/ESIME.2006.1644039","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1644039","url":null,"abstract":"A method for the characterization of mechanical properties of freestanding thin metal film materials used in RF-MEMS is evaluated. Freestanding beam structures are manufactured from a sputtered layer of AlCu(1wt%) on top of a wafer using an industrialized RF-MEMS manufacturing process. The methods of examining micro structure and geometry are studied. It is shown that these methods are promising for extracting the desired information about the material. Simple bending experiments are carried out on micro-scale beams of varying length and thickness using an indenter device. Elastic material properties are extracted from the results, using finite element technology combined with elastic theory, removing the necessity of extensive finite element simulations. It is shown that the beam length and indenter positioning play a crucial role. The obtained results show agreement with expected values for longer beams, but no obvious relation with the film thickness is found within the experimental range addressed","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"27 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85585733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1644066
K. Jansen, L. Ernst, H. Bressers
The present state-of-the-art in simulation of stresses in electronic packages is to model the moulding compound as a viscoelastic material. That means that stresses during packaging and subsequent thermomechanical loading are allowed to relax partially. Such an approach was seen to improve thermomechanical predictions considerably compared to the previously used temperature dependent elastic models. Therefore viscoelastic simulations are now becoming the standard for the modelling of packaging stresses and viscoelastic characterization of new moulding compound materials is now routinely being performed by most of the companies involved with packaging of electronic components. A problem is, however, that the viscoelastic data of moulding compounds turns out to be quite sensitive to variations in the compound chemistry and that this chemistry may vary slightly from batch to batch. Since these variations do not have a large effect on the room temperature properties (like the modulus) they often remain undetected by the standard quality tests. In order to anticipate to these problems it is desirable to develop a fundamental understanding of what parameters influence the viscoelastic properties of thermosets. A quantitative model, such as will be presented in this paper, has the additional advantage that it can be used for the selection of moulding compounds with optimized viscoelastic properties
{"title":"Effect of Chemistry on Viscoelastic Properties of Moulding Compounds","authors":"K. Jansen, L. Ernst, H. Bressers","doi":"10.1109/ESIME.2006.1644066","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1644066","url":null,"abstract":"The present state-of-the-art in simulation of stresses in electronic packages is to model the moulding compound as a viscoelastic material. That means that stresses during packaging and subsequent thermomechanical loading are allowed to relax partially. Such an approach was seen to improve thermomechanical predictions considerably compared to the previously used temperature dependent elastic models. Therefore viscoelastic simulations are now becoming the standard for the modelling of packaging stresses and viscoelastic characterization of new moulding compound materials is now routinely being performed by most of the companies involved with packaging of electronic components. A problem is, however, that the viscoelastic data of moulding compounds turns out to be quite sensitive to variations in the compound chemistry and that this chemistry may vary slightly from batch to batch. Since these variations do not have a large effect on the room temperature properties (like the modulus) they often remain undetected by the standard quality tests. In order to anticipate to these problems it is desirable to develop a fundamental understanding of what parameters influence the viscoelastic properties of thermosets. A quantitative model, such as will be presented in this paper, has the additional advantage that it can be used for the selection of moulding compounds with optimized viscoelastic properties","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"106 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79559299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1644030
M. van Soestbergen, L. Ernst, K. Jansen, W. V. van Driel, M. Bartek, A. Polyakov
The ongoing miniaturization of microelectronics has led to low-K polymer dielectric films with a thickness of several tens of nanometers. These thin polymer films generally show time dependent material properties, that are different in lateral directions and in-thickness direction. Most techniques available for measuring the mechanical properties of thin films are only capable of obtaining the in-plane modulus. To have an in-situ measurement of the in-thickness viscoelastic modulus, a parallel plate capacitor under hydrostatic pressure is used. An interdigitated electrode is used to capture the change in dielectric constant under pressure. As a first estimation, a BCB (benzocyclobutene) film was used. The in-thickness elastic modulus and change in permittivity for a 1.3 mum thick BCB (Cyclotenetrade 4022) film sandwiched between two alumina electrodes on a silicon wafer are reported to be 4.76plusmn0.42, 3.81plusmn0.26 and 3.16plusmn0.15 GPa for 20deg;, 50 deg; and 70deg; C respectively
{"title":"Measuring In-Thickness Mechanical Properties of Sub Micron Polymer Dielectric Films","authors":"M. van Soestbergen, L. Ernst, K. Jansen, W. V. van Driel, M. Bartek, A. Polyakov","doi":"10.1109/ESIME.2006.1644030","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1644030","url":null,"abstract":"The ongoing miniaturization of microelectronics has led to low-K polymer dielectric films with a thickness of several tens of nanometers. These thin polymer films generally show time dependent material properties, that are different in lateral directions and in-thickness direction. Most techniques available for measuring the mechanical properties of thin films are only capable of obtaining the in-plane modulus. To have an in-situ measurement of the in-thickness viscoelastic modulus, a parallel plate capacitor under hydrostatic pressure is used. An interdigitated electrode is used to capture the change in dielectric constant under pressure. As a first estimation, a BCB (benzocyclobutene) film was used. The in-thickness elastic modulus and change in permittivity for a 1.3 mum thick BCB (Cyclotenetrade 4022) film sandwiched between two alumina electrodes on a silicon wafer are reported to be 4.76plusmn0.42, 3.81plusmn0.26 and 3.16plusmn0.15 GPa for 20deg;, 50 deg; and 70deg; C respectively","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"26 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78086906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1643973
R. Mathieu, W. Eric, A. Stephane
This paper presents a reliability study of power assemblies based on the correlation of finite element simulations and experimental results. For these power modules, a new process was used to solder bare dice on a copper lead frame with a local heating source. The reliability methodology we are using is based on the evaluation of the strain energy density accumulated in the solder joint during the lifetime of the assembly. The study was also carried out on various types of solder. Two series of simulations have been carried out in parallel. The first series was the simulation of a classical reflow process with a uniform temperature of 300degC in the whole assembly. The second one was the simulation of the new process with localized heating. The comparison of the results of the simulations allowed concluding that this new process does not introduce more strain than a normal process. In order to evaluate the lifetime of the assembly, ageing tests have been carried out on representative test vehicles. By correlation between simulations and ageing tests, we have evaluated the lifetime of the assembly under operation conditions
{"title":"Reliability Analysis of a New Soldering Process For Automotive Power Modules Application","authors":"R. Mathieu, W. Eric, A. Stephane","doi":"10.1109/ESIME.2006.1643973","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1643973","url":null,"abstract":"This paper presents a reliability study of power assemblies based on the correlation of finite element simulations and experimental results. For these power modules, a new process was used to solder bare dice on a copper lead frame with a local heating source. The reliability methodology we are using is based on the evaluation of the strain energy density accumulated in the solder joint during the lifetime of the assembly. The study was also carried out on various types of solder. Two series of simulations have been carried out in parallel. The first series was the simulation of a classical reflow process with a uniform temperature of 300degC in the whole assembly. The second one was the simulation of the new process with localized heating. The comparison of the results of the simulations allowed concluding that this new process does not introduce more strain than a normal process. In order to evaluate the lifetime of the assembly, ageing tests have been carried out on representative test vehicles. By correlation between simulations and ageing tests, we have evaluated the lifetime of the assembly under operation conditions","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"21 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74019721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1644025
G. Signoriello, M. Beghi, A. Rusconi Clerici, G. Spinola
Brillouin scattering, the scattering of light by ultrasonic waves, offers the possibility to probe the velocity of acoustic modes at sub-micrometric wavelength. From the acoustic properties the elastic properties can be derived. In the case of transparent films both bulk and surface acoustic waves can be measured. Brillouin scattering has been exploited to characterize a silica layer of micrometric thickness, thermally grown on a silicon substrate. The observation of different scattering geometries allowed to measure both the Young modulus and Poisson's ratio of the silica film, together with its refractive index
{"title":"Complete elastic characterization of a silica layer by Brillouin scattering","authors":"G. Signoriello, M. Beghi, A. Rusconi Clerici, G. Spinola","doi":"10.1109/ESIME.2006.1644025","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1644025","url":null,"abstract":"Brillouin scattering, the scattering of light by ultrasonic waves, offers the possibility to probe the velocity of acoustic modes at sub-micrometric wavelength. From the acoustic properties the elastic properties can be derived. In the case of transparent films both bulk and surface acoustic waves can be measured. Brillouin scattering has been exploited to characterize a silica layer of micrometric thickness, thermally grown on a silicon substrate. The observation of different scattering geometries allowed to measure both the Young modulus and Poisson's ratio of the silica film, together with its refractive index","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"13 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78813669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2006-04-24DOI: 10.1109/ESIME.2006.1644028
Jiang Zhou
The characterization of the hygroscopic property for the packaging materials presents unique challenges, which are not adequately addressed in current methods. One of those challenges is the impact of non-uniform moisture distribution across the specimen. Our recent studies have shown that the current averaged approach might overestimate the coefficient of hygroscopic swelling as much as 250%. In our previous analysis, however, the hygroscopic stress induced deformation has not been taken into consideration. As a matter of fact, due to non-uniform moisture distribution during the test, the total measured deformation includes the hygroscopic swelling itself, and the hygroscopic stress induced deformation. In this paper, a comprehensive study is performed on the impacts of non-uniform moisture distribution and the effect of hygroscopic stress by using sequentially coupled moisture diffusion and hygroscopic stress modeling approach. The results show that the hygroscopic stress induced displacement is relatively small, although the elastic strain caused by the hygroscopic stress accounts for about one third of the total strain. The results in our previous study are proved to be acceptably accurate, even through the hygroscopic stress induced elastic deformation has been neglected
{"title":"Sequentially-Coupled Finite Element Transient Analysis with Hygroscopic Swelling","authors":"Jiang Zhou","doi":"10.1109/ESIME.2006.1644028","DOIUrl":"https://doi.org/10.1109/ESIME.2006.1644028","url":null,"abstract":"The characterization of the hygroscopic property for the packaging materials presents unique challenges, which are not adequately addressed in current methods. One of those challenges is the impact of non-uniform moisture distribution across the specimen. Our recent studies have shown that the current averaged approach might overestimate the coefficient of hygroscopic swelling as much as 250%. In our previous analysis, however, the hygroscopic stress induced deformation has not been taken into consideration. As a matter of fact, due to non-uniform moisture distribution during the test, the total measured deformation includes the hygroscopic swelling itself, and the hygroscopic stress induced deformation. In this paper, a comprehensive study is performed on the impacts of non-uniform moisture distribution and the effect of hygroscopic stress by using sequentially coupled moisture diffusion and hygroscopic stress modeling approach. The results show that the hygroscopic stress induced displacement is relatively small, although the elastic strain caused by the hygroscopic stress accounts for about one third of the total strain. The results in our previous study are proved to be acceptably accurate, even through the hygroscopic stress induced elastic deformation has been neglected","PeriodicalId":60796,"journal":{"name":"微纳电子与智能制造","volume":"21 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2006-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78889614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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