Pub Date : 2002-08-07DOI: 10.1109/ITHERM.2002.1012544
P. Towashiraporn, G. Subbarayan, B. McIlvanie, B. Hunter, D. Love, B. Sullivan
Empirical fatigue life models such as the Coffin-Manson rule and its variants are commonly used at the present time to predict the reliability of microelectronic packages. While there have been reports of substantial error in empirical correlations relative to the experiments, this has not been accompanied by a rigorous understanding of the sources of the error. In this paper we systematically explore the various modeling errors in the fatigue life prediction. These errors include those in geometry representation, material behavior, load history and boundary condition application, and in the numerical solution procedure. As part of the study, experimentally validated correlations between temperature cycling and power-cycling are developed for a TI 144 chip-scale package. The accuracy of the predicted life under power-cycling conditions compared to the experimentally determined life is used as the basis for judging the model accuracy. The criticality of spatial refinement, temporal refinement, and accurate boundary conditions, including the often ignored natural convection boundary conditions, and their effect on predicted life is described in detail. It is shown that model errors can be a significant part of both the constitutive life models and the application models that use the constitutive life models to predict the fatigue life under a given environmental condition. It is also shown that with careful model building, solutions accurate to within 5% can be obtained.
{"title":"The effect of model building on the accuracy of fatigue life predictions in electronic packages","authors":"P. Towashiraporn, G. Subbarayan, B. McIlvanie, B. Hunter, D. Love, B. Sullivan","doi":"10.1109/ITHERM.2002.1012544","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012544","url":null,"abstract":"Empirical fatigue life models such as the Coffin-Manson rule and its variants are commonly used at the present time to predict the reliability of microelectronic packages. While there have been reports of substantial error in empirical correlations relative to the experiments, this has not been accompanied by a rigorous understanding of the sources of the error. In this paper we systematically explore the various modeling errors in the fatigue life prediction. These errors include those in geometry representation, material behavior, load history and boundary condition application, and in the numerical solution procedure. As part of the study, experimentally validated correlations between temperature cycling and power-cycling are developed for a TI 144 chip-scale package. The accuracy of the predicted life under power-cycling conditions compared to the experimentally determined life is used as the basis for judging the model accuracy. The criticality of spatial refinement, temporal refinement, and accurate boundary conditions, including the often ignored natural convection boundary conditions, and their effect on predicted life is described in detail. It is shown that model errors can be a significant part of both the constitutive life models and the application models that use the constitutive life models to predict the fatigue life under a given environmental condition. It is also shown that with careful model building, solutions accurate to within 5% can be obtained.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131799193","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012554
S. Hedge, R. Pucha, A. Takahashi, N. Takano, S. Sitaraman
The thermomechanical response of multi-layered high density wiring (HDW) substrates is influenced by various material and geometrical parameters. This study aims at understanding the role and interaction of various dielectric and base substrate materials on different failure mechanisms. Experimental thermals cycling results are presented and the failure modes observed in test samples are discussed. Nonlinear finite element models are developed to estimate the warpage of the substrate, stresses in the dielectric layer and solder bump strains. The input factors for the analysis are grouped under material properties and geometry, and a selection technique is used to identify important factors. Based on the study, a response surface is generated to understand the role and interaction of input parameters on various failure mechanisms, and such a response surface will be used to tailor material properties for the High Density Wiring (HDW) structures.
{"title":"Thermomechanical reliability of high density wiring substrates","authors":"S. Hedge, R. Pucha, A. Takahashi, N. Takano, S. Sitaraman","doi":"10.1109/ITHERM.2002.1012554","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012554","url":null,"abstract":"The thermomechanical response of multi-layered high density wiring (HDW) substrates is influenced by various material and geometrical parameters. This study aims at understanding the role and interaction of various dielectric and base substrate materials on different failure mechanisms. Experimental thermals cycling results are presented and the failure modes observed in test samples are discussed. Nonlinear finite element models are developed to estimate the warpage of the substrate, stresses in the dielectric layer and solder bump strains. The input factors for the analysis are grouped under material properties and geometry, and a selection technique is used to identify important factors. Based on the study, a response surface is generated to understand the role and interaction of input parameters on various failure mechanisms, and such a response surface will be used to tailor material properties for the High Density Wiring (HDW) structures.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132350869","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012520
R. Grimes, M. Davies
This paper investigates the effects of fan operating point and location on the temperature distribution in a simple test electronic system. First the investigation is performed with the fan mounted at the system outlet and drawing air through the system. Then the investigation is performed with the fan mounted at system inlet, pushing air through the system. Both cases were investigated at three flow rates within the fan's recommended operating range. In each case, Particle Image Velocimetry (PIV) was used to measure system air flow and infra red thermography was used to measure PCB surface temperature. At each flow rate examined, PIV showed the air velocity to be uniform in direction and magnitude in the system with the fan mounted at system outlet, with local velocities changing in proportion to the flow rate. PCB temperature increased with reduced flow rate. In the system with the fan mounted at inlet, flow had large tangential components, impingement onto the PCB and reverse flow. Mean PCB temperature was found to be unchanged by flow rate, due to the increased thermal mixing which occurred at lower flow rates. This paper illustrates the gains, which can be made through correct fan placement, and discusses how heat transfer coefficients within fan cooled electronic systems can be optimised throughout the fan operating range.
{"title":"The effect of fan operating point and location on temperature distribution in electronic systems","authors":"R. Grimes, M. Davies","doi":"10.1109/ITHERM.2002.1012520","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012520","url":null,"abstract":"This paper investigates the effects of fan operating point and location on the temperature distribution in a simple test electronic system. First the investigation is performed with the fan mounted at the system outlet and drawing air through the system. Then the investigation is performed with the fan mounted at system inlet, pushing air through the system. Both cases were investigated at three flow rates within the fan's recommended operating range. In each case, Particle Image Velocimetry (PIV) was used to measure system air flow and infra red thermography was used to measure PCB surface temperature. At each flow rate examined, PIV showed the air velocity to be uniform in direction and magnitude in the system with the fan mounted at system outlet, with local velocities changing in proportion to the flow rate. PCB temperature increased with reduced flow rate. In the system with the fan mounted at inlet, flow had large tangential components, impingement onto the PCB and reverse flow. Mean PCB temperature was found to be unchanged by flow rate, due to the increased thermal mixing which occurred at lower flow rates. This paper illustrates the gains, which can be made through correct fan placement, and discusses how heat transfer coefficients within fan cooled electronic systems can be optimised throughout the fan operating range.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"86 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117271549","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012439
R. Cole, M. Davies
Numerical modeling is a valuable analysis tool, however it is still a time consuming process and it is imperative that models be validated. The authors have proposed an alternative to full-scale numerical modeling as a first level design tool, which involves the use aerodynamic and thermal influence factors. Cole et al. [2001] presented a ball grid array (BGA) test apparatus, and also presented aerodynamic measurements made using particle image velocimetry (PIV). Part II of that paper presented thermal resistance measurements, influence factors calculated, and infrared images of surface temperatures. This paper presents numerical models made with an industry standard computational fluid dynamics (CFD) package, using the benchmark data provided from the previous work. The objective is to validate the numerical models, in order to be able to examine additional geometries.
{"title":"Numerical analysis of an array of ball grid components","authors":"R. Cole, M. Davies","doi":"10.1109/ITHERM.2002.1012439","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012439","url":null,"abstract":"Numerical modeling is a valuable analysis tool, however it is still a time consuming process and it is imperative that models be validated. The authors have proposed an alternative to full-scale numerical modeling as a first level design tool, which involves the use aerodynamic and thermal influence factors. Cole et al. [2001] presented a ball grid array (BGA) test apparatus, and also presented aerodynamic measurements made using particle image velocimetry (PIV). Part II of that paper presented thermal resistance measurements, influence factors calculated, and infrared images of surface temperatures. This paper presents numerical models made with an industry standard computational fluid dynamics (CFD) package, using the benchmark data provided from the previous work. The objective is to validate the numerical models, in order to be able to examine additional geometries.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115019435","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012578
B. P. Gundale, S. Misra
Copper clad insulated metal substrates (IMS/spl trade/) can be a solution for thermal problems caused by high power density. An IMS is a metal board laminated to a circuit layer with a thermally conductive dielectric. The dielectric's thermal conductivity and thickness are critical to the thermal performance of the electronic assembly. These parameters were experimentally evaluated using a TO-220 package as a heat source. In addition, a detailed model was built using the CFD software Flotherm/spl trade/. The predicted thermal performance matches the data well if experimental data is used to correlate the model. This study indicates that for a given dielectric thickness, the thermal impedance reduces to its asymptotic value at a characteristic thermal conductivity. For a relatively thin dielectric of 75 /spl mu/m, a thermal conductivity of 4 W/m-K is sufficient, while for a thick dielectric of 250 /spl mu/m, maximum performance is not achieved until about 8 W/m-K.
{"title":"Thermal performance of IMS/spl trade/ dielectrics: data and prediction","authors":"B. P. Gundale, S. Misra","doi":"10.1109/ITHERM.2002.1012578","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012578","url":null,"abstract":"Copper clad insulated metal substrates (IMS/spl trade/) can be a solution for thermal problems caused by high power density. An IMS is a metal board laminated to a circuit layer with a thermally conductive dielectric. The dielectric's thermal conductivity and thickness are critical to the thermal performance of the electronic assembly. These parameters were experimentally evaluated using a TO-220 package as a heat source. In addition, a detailed model was built using the CFD software Flotherm/spl trade/. The predicted thermal performance matches the data well if experimental data is used to correlate the model. This study indicates that for a given dielectric thickness, the thermal impedance reduces to its asymptotic value at a characteristic thermal conductivity. For a relatively thin dielectric of 75 /spl mu/m, a thermal conductivity of 4 W/m-K is sufficient, while for a thick dielectric of 250 /spl mu/m, maximum performance is not achieved until about 8 W/m-K.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115166202","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012518
E. Marotta, S. Lafontant, D. McClafferty, S. Mazzuca
Increasingly, thermal interstitial materials (TIM), such as metallic foils, solder, metallic coatings, polymeric matrices loaded with highly conducting filler particles (i.e., elastomers), greases, and phase-change (PCM) materials are being employed to a greater extent in power generating systems. With greater use, follow an increased interest in the thermal transport and mechanical properties of these materials. These properties include thermal conductivity, thermal diffusivity, Young's modulus, Poisson's ratio, and the thermal resistance at the interface between the interstitial material with the substrate material. To provide information on the thermal joint conductance of an important interstitial material employed in microelectronic components, an experimental investigation has been conducted for flexible graphite. The experimental data were compared to an analytical model developed for elastic layers. The model and data are found to be in good agreement over the pressure range within the investigation. The proposed model can be used to predict the lower bound on the joint conductance.
{"title":"The effect of interface pressure on thermal joint conductance for flexible graphite materials: analytical and experimental study","authors":"E. Marotta, S. Lafontant, D. McClafferty, S. Mazzuca","doi":"10.1109/ITHERM.2002.1012518","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012518","url":null,"abstract":"Increasingly, thermal interstitial materials (TIM), such as metallic foils, solder, metallic coatings, polymeric matrices loaded with highly conducting filler particles (i.e., elastomers), greases, and phase-change (PCM) materials are being employed to a greater extent in power generating systems. With greater use, follow an increased interest in the thermal transport and mechanical properties of these materials. These properties include thermal conductivity, thermal diffusivity, Young's modulus, Poisson's ratio, and the thermal resistance at the interface between the interstitial material with the substrate material. To provide information on the thermal joint conductance of an important interstitial material employed in microelectronic components, an experimental investigation has been conducted for flexible graphite. The experimental data were compared to an analytical model developed for elastic layers. The model and data are found to be in good agreement over the pressure range within the investigation. The proposed model can be used to predict the lower bound on the joint conductance.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123549918","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012515
J. Gwinn, M. Saini, R. Webb
This manuscript describes a systematic and rational design of an experimental apparatus based on ASTM D-5470 standard for thermal interface resistance measurement of high performance thermal interface materials (TIM). The apparatus is intended to provide measurement of TIM thermal resistance as low as 0.065 K-cm/sup 2//W within 10% experimental uncertainty. The key points addressed are: 1) Apparatus design to obtain accurate measurement of TIM surface temperatures and heat flux, 2) Effects of surface flatness and roughness, and 3) Importance of and methods for surface cleaning. Design criteria are presented for choosing temperature sensors, their installation method, meter-bar material and thickness. The temperature sensors in the meter-bars should be located a sufficient distance from the heaters to ensure uniform heat flux in the thermal sensor region. Cooling plate design specifications, and a method for applying interface pressure are described. Experimental data are presented on a new TIM having 0.058 K-cm/sup 2//W interface resistance with 138 kPa contact pressure, which is lower than commercially available thermal grease and phase change materials.
{"title":"Apparatus for accurate measurement of interface resistance of high performance thermal interface materials","authors":"J. Gwinn, M. Saini, R. Webb","doi":"10.1109/ITHERM.2002.1012515","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012515","url":null,"abstract":"This manuscript describes a systematic and rational design of an experimental apparatus based on ASTM D-5470 standard for thermal interface resistance measurement of high performance thermal interface materials (TIM). The apparatus is intended to provide measurement of TIM thermal resistance as low as 0.065 K-cm/sup 2//W within 10% experimental uncertainty. The key points addressed are: 1) Apparatus design to obtain accurate measurement of TIM surface temperatures and heat flux, 2) Effects of surface flatness and roughness, and 3) Importance of and methods for surface cleaning. Design criteria are presented for choosing temperature sensors, their installation method, meter-bar material and thickness. The temperature sensors in the meter-bars should be located a sufficient distance from the heaters to ensure uniform heat flux in the thermal sensor region. Cooling plate design specifications, and a method for applying interface pressure are described. Experimental data are presented on a new TIM having 0.058 K-cm/sup 2//W interface resistance with 138 kPa contact pressure, which is lower than commercially available thermal grease and phase change materials.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122039792","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012455
M. Zampino, R. Kandukuri, W. Jones
Increased power densities in devices are placing greater demands in system level thermal management. New developments in low temperature cofire ceramic (LTCC) have allowed the fabrication of high thermal conductivity via arrays. New materials, including unloaded via inks and cofire Ag tape, allow the development of thermal via structure with effective thermal conductivities exceeding 250 W/m/spl deg/K. To accurately predict the thermal performance, the value of thermal conductivity must be known. Thermal conductivity has been measured by flash diffusivity for a number of commercially available LTCC ceramics and via fill materials, with the via materials approaching 300 W/m/spl deg/K.
{"title":"High performance thermal vias in LTCC substrates","authors":"M. Zampino, R. Kandukuri, W. Jones","doi":"10.1109/ITHERM.2002.1012455","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012455","url":null,"abstract":"Increased power densities in devices are placing greater demands in system level thermal management. New developments in low temperature cofire ceramic (LTCC) have allowed the fabrication of high thermal conductivity via arrays. New materials, including unloaded via inks and cofire Ag tape, allow the development of thermal via structure with effective thermal conductivities exceeding 250 W/m/spl deg/K. To accurately predict the thermal performance, the value of thermal conductivity must be known. Thermal conductivity has been measured by flash diffusivity for a number of commercially available LTCC ceramics and via fill materials, with the via materials approaching 300 W/m/spl deg/K.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122703318","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012530
M. Tahmaspur, M. Berhe
The TW-150 unit is a thermally hardened product designed to operate under harsh ambient conditions ranging from -40 to 75/spl deg/C and altitudes of up to 13,000 ft above sea level. The unit is designed so that the case and junction temperatures of any component should not exceed 85 and 90/spl deg/C, respectively. Further, the case temperature of the optical module is to be limited to 76/spl deg/C under all operating conditions. Extensive thermal analysis was conducted so that the box operates reliably under these conditions with an acceptable mean time between failure. We present comparison of CFD results with experiments for selected cases. We then discuss transient modeling and fan failure analysis, the effects of fan speed and altitude on temperature of components, and comparison of honeycomb vent with perforated plate vent. We then discuss miscellaneous effects such as the effects of fan power, leakage through small gaps in the system, and placement of temperature sensors inside the unit.
{"title":"Thermal design of the TW-150 passive optical network access unit. II","authors":"M. Tahmaspur, M. Berhe","doi":"10.1109/ITHERM.2002.1012530","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012530","url":null,"abstract":"The TW-150 unit is a thermally hardened product designed to operate under harsh ambient conditions ranging from -40 to 75/spl deg/C and altitudes of up to 13,000 ft above sea level. The unit is designed so that the case and junction temperatures of any component should not exceed 85 and 90/spl deg/C, respectively. Further, the case temperature of the optical module is to be limited to 76/spl deg/C under all operating conditions. Extensive thermal analysis was conducted so that the box operates reliably under these conditions with an acceptable mean time between failure. We present comparison of CFD results with experiments for selected cases. We then discuss transient modeling and fan failure analysis, the effects of fan speed and altitude on temperature of components, and comparison of honeycomb vent with perforated plate vent. We then discuss miscellaneous effects such as the effects of fan power, leakage through small gaps in the system, and placement of temperature sensors inside the unit.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"149 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116206069","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 : 2002-08-07DOI: 10.1109/ITHERM.2002.1012566
P. Greenfield, J. Pitarresi, G. Lehmann, D. Skinner, J. Lee, B. Sammakia, J. Zou
Historically, the research and development for large flat panel displays has focused on gas plasma devices. Another type of display under consideration uses a series of individual LCD panels to form a large monolithic display. The objective of this study involves the lamination of the tiles into a single composite assembly. A final cover is placed over a subassembly of tiles which when butted together, can vary in thickness by up to 25 microns. The attachment mechanism for this process uses a single sheet adhesive to set the initial gap thickness. A second layer of a liquid adhesive is used to compensate for geometry variations in the tiles. ne process of squeezing the cover onto the tiles is characterized in terms of the squeeze times, directionality, and void development. Two primary mechanisms were found involving the generation of voids and bubbles; the first relating to the out gassing of the volatile components in the adhesive and the second relating to entrainment or hydrodynamic mechanisms associated with squeeze flows and surface topology of the sheet adhesive.
{"title":"A lamination study of a composite LCD flat panel display","authors":"P. Greenfield, J. Pitarresi, G. Lehmann, D. Skinner, J. Lee, B. Sammakia, J. Zou","doi":"10.1109/ITHERM.2002.1012566","DOIUrl":"https://doi.org/10.1109/ITHERM.2002.1012566","url":null,"abstract":"Historically, the research and development for large flat panel displays has focused on gas plasma devices. Another type of display under consideration uses a series of individual LCD panels to form a large monolithic display. The objective of this study involves the lamination of the tiles into a single composite assembly. A final cover is placed over a subassembly of tiles which when butted together, can vary in thickness by up to 25 microns. The attachment mechanism for this process uses a single sheet adhesive to set the initial gap thickness. A second layer of a liquid adhesive is used to compensate for geometry variations in the tiles. ne process of squeezing the cover onto the tiles is characterized in terms of the squeeze times, directionality, and void development. Two primary mechanisms were found involving the generation of voids and bubbles; the first relating to the out gassing of the volatile components in the adhesive and the second relating to entrainment or hydrodynamic mechanisms associated with squeeze flows and surface topology of the sheet adhesive.","PeriodicalId":299933,"journal":{"name":"ITherm 2002. Eighth Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (Cat. No.02CH37258)","volume":"13 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120840767","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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