Pub Date : 2011-12-29DOI: 10.1109/IMPACT.2011.6117256
Kuo-ying Tsai, Shih-chang Ku, W. Chang, H. Tsai
The thermal performance of a specific 3D IC structure — a wide I/O package is investigated with parameterized factors like TSV diameter, material of micro bumps, and TSV allocation strategy. TSV diameter and material of micro bump are found no significant effect on thermal performance of the illustrated wide I/O package. However, the hot spot location is changed by the TSV allocation. The results suggest the better locations for thermal diodes would be close to the TSV or die corners. Also this work concludes that the “TSV peripheral” allocation performs the better cooling than the others.
{"title":"Thermal characterization of a wide I/O 3DIC","authors":"Kuo-ying Tsai, Shih-chang Ku, W. Chang, H. Tsai","doi":"10.1109/IMPACT.2011.6117256","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117256","url":null,"abstract":"The thermal performance of a specific 3D IC structure — a wide I/O package is investigated with parameterized factors like TSV diameter, material of micro bumps, and TSV allocation strategy. TSV diameter and material of micro bump are found no significant effect on thermal performance of the illustrated wide I/O package. However, the hot spot location is changed by the TSV allocation. The results suggest the better locations for thermal diodes would be close to the TSV or die corners. Also this work concludes that the “TSV peripheral” allocation performs the better cooling than the others.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"26 1","pages":"261-264"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81051577","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117171
T. Tomimura, M. Ishizuka
Related to the thermal contact resistance, lots of studies have been done on the thermal constriction resistance, which is a measure of the additional temperature drop at the contact interface [1]. And almost all of those studies have been conducted based on the two-dimensional cylindrical coordinates system. In the same way, the additional thermal resistance associated with the geometrical constriction is often encountered in the electronic components like relay circuits, the printed circuit boards, and so on. In these cases, however, heat is frequently transferred through a thin and narrow passage, which should be treated by two-dimensional rectangular coordinates system.
{"title":"Estimation of thermal constriction resistance for simple thermal network analysis of electronic components","authors":"T. Tomimura, M. Ishizuka","doi":"10.1109/IMPACT.2011.6117171","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117171","url":null,"abstract":"Related to the thermal contact resistance, lots of studies have been done on the thermal constriction resistance, which is a measure of the additional temperature drop at the contact interface [1]. And almost all of those studies have been conducted based on the two-dimensional cylindrical coordinates system. In the same way, the additional thermal resistance associated with the geometrical constriction is often encountered in the electronic components like relay circuits, the printed circuit boards, and so on. In these cases, however, heat is frequently transferred through a thin and narrow passage, which should be treated by two-dimensional rectangular coordinates system.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"43 1","pages":"246-248"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88054503","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117207
Christian Alvin, W. Chu, Ching-hung Cheng, J. Teng
Light Emitting Diode or LED now is becoming a popular lighting used at many types of applications. LED becomes more favorable to use than other types of lighting such as fluorescent or even light bulb. This is because LED can provide high lumens with low power electricity and does not contain any toxic material, such as fluorescent lights having mercury inside which is not good towards the environment. Advantages of using LED are high luminosity, more energy saving, high lifetime hours, and applicable in many applications. However, LED operating temperature should be considered. LEDs with high power, such as 10 Watts or more, can generate bright lighting, but also will have high operating temperature. This high operating temperature of LED should be lowered, since high operating temperature will lead to reductions of the luminosity and the lifetime of LED. Many cooling systems can be used to reduce the operating temperature of LED; a simple one is to use the extruded-fin heat sink. Heat sink is easy to manufacture, relatively low in cost, light in weight, and can become an adequate cooling means with good reliability. The choice of an optimal heat sink dimension depends on the power of heat source. In this work, 10-Watt LED with the 58 °C operating temperature was used. The aim for this study was to add extruded-fin heat sink to dissipate heat generated by the LED, with target temperature of LED decreased down to 50°C. Initial experiment was done to check the LED operating temperature and then ANSYS ICEPAK was used for numerical simulation; ANSYS ICEPAK is computational software for the study of thermal management of electronic devices and systems. For the present study, the numerical simulation of LED using extruded-fin as heat sink was performed. Through numerical simulation accounting for the variations in fin heights, fin thicknesses, fin pitches, and base heights, the optimal dimension of the heat sink was determined to achieve the target temperature of 50°C. Subsequently, prototype of aluminum fin heat sink was build to carry out the experiments for the purpose of validating the results obtained from numerical simulations. In the experiment, two kinds of thermal conductive pastes — a heat transfer compound and silver paste — were used to assemble the heat sink and LED. The effect of thermal conductive pastes on the overall thermal management of LED was investigated. Through the experiments, silver paste was proven to enhance the thermal conductivity, measured by the heat sink thermal resistance, reducing 0.02 °C/W compared with those using heat transfer compound. Both experimental tests and numerical simulations were done. Results obtained from the experiments and those obtained from the simulations were in good agreement, having percentage of differences less than 12%. From this study, it was shown that heat sinks with a good thermal conductive paste have proven to be an effective solution for the LED heat dissipation. Using ANSYS ICEPAK a
{"title":"Thermal analysis of extruded aluminum fin heat sink for LED cooling application","authors":"Christian Alvin, W. Chu, Ching-hung Cheng, J. Teng","doi":"10.1109/IMPACT.2011.6117207","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117207","url":null,"abstract":"Light Emitting Diode or LED now is becoming a popular lighting used at many types of applications. LED becomes more favorable to use than other types of lighting such as fluorescent or even light bulb. This is because LED can provide high lumens with low power electricity and does not contain any toxic material, such as fluorescent lights having mercury inside which is not good towards the environment. Advantages of using LED are high luminosity, more energy saving, high lifetime hours, and applicable in many applications. However, LED operating temperature should be considered. LEDs with high power, such as 10 Watts or more, can generate bright lighting, but also will have high operating temperature. This high operating temperature of LED should be lowered, since high operating temperature will lead to reductions of the luminosity and the lifetime of LED. Many cooling systems can be used to reduce the operating temperature of LED; a simple one is to use the extruded-fin heat sink. Heat sink is easy to manufacture, relatively low in cost, light in weight, and can become an adequate cooling means with good reliability. The choice of an optimal heat sink dimension depends on the power of heat source. In this work, 10-Watt LED with the 58 °C operating temperature was used. The aim for this study was to add extruded-fin heat sink to dissipate heat generated by the LED, with target temperature of LED decreased down to 50°C. Initial experiment was done to check the LED operating temperature and then ANSYS ICEPAK was used for numerical simulation; ANSYS ICEPAK is computational software for the study of thermal management of electronic devices and systems. For the present study, the numerical simulation of LED using extruded-fin as heat sink was performed. Through numerical simulation accounting for the variations in fin heights, fin thicknesses, fin pitches, and base heights, the optimal dimension of the heat sink was determined to achieve the target temperature of 50°C. Subsequently, prototype of aluminum fin heat sink was build to carry out the experiments for the purpose of validating the results obtained from numerical simulations. In the experiment, two kinds of thermal conductive pastes — a heat transfer compound and silver paste — were used to assemble the heat sink and LED. The effect of thermal conductive pastes on the overall thermal management of LED was investigated. Through the experiments, silver paste was proven to enhance the thermal conductivity, measured by the heat sink thermal resistance, reducing 0.02 °C/W compared with those using heat transfer compound. Both experimental tests and numerical simulations were done. Results obtained from the experiments and those obtained from the simulations were in good agreement, having percentage of differences less than 12%. From this study, it was shown that heat sinks with a good thermal conductive paste have proven to be an effective solution for the LED heat dissipation. Using ANSYS ICEPAK a","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"14 1","pages":"397-400"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87029916","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117269
De-Shin Liu, I. Lin
The moisture diffusion phenomenon of UV-curable adhesive apply to the packaging of organic light-emitting devices (OLEDs) were investigated. Owing to the sensitivity of moisture ingress into OLEDs package, how to against the moisture permeation will be one of the key design issue. As regards to improve the moisture-resistant capability of the materials for encapsulating, one possible way is to add particles into UV-curable sealing adhesive. In this study, a numerical simulation model that contained randomly distributed particles into heterogeneous epoxy resin has been developed. The commercial software MATLAB is employed to generate the location of randomly distributed particles and the commercial software ANSYS based on the finite element method is employed to analyze moisture diffusion in containing multiple randomly distributed particles. Furthermore, this model is then employed to investigate the relationship between the volume fraction of the particles in the resin composite and the rate of moisture diffusion. The simulation results show that moisture diffusion is retarded significantly as the volume fraction of particles increases. Moreover, the adhesive with high volume fraction of particle exhibits superior moisture-resistant capability. However, excessively add particles makes inferior penetrability. Therefore, adding proper volume percentage of particle into UV-curable adhesive could be expected better using in engineering applications.
{"title":"Modeling of moisture diffusion in heterogeneous epoxy resin containing multiple randomly distributed particles using finite element method","authors":"De-Shin Liu, I. Lin","doi":"10.1109/IMPACT.2011.6117269","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117269","url":null,"abstract":"The moisture diffusion phenomenon of UV-curable adhesive apply to the packaging of organic light-emitting devices (OLEDs) were investigated. Owing to the sensitivity of moisture ingress into OLEDs package, how to against the moisture permeation will be one of the key design issue. As regards to improve the moisture-resistant capability of the materials for encapsulating, one possible way is to add particles into UV-curable sealing adhesive. In this study, a numerical simulation model that contained randomly distributed particles into heterogeneous epoxy resin has been developed. The commercial software MATLAB is employed to generate the location of randomly distributed particles and the commercial software ANSYS based on the finite element method is employed to analyze moisture diffusion in containing multiple randomly distributed particles. Furthermore, this model is then employed to investigate the relationship between the volume fraction of the particles in the resin composite and the rate of moisture diffusion. The simulation results show that moisture diffusion is retarded significantly as the volume fraction of particles increases. Moreover, the adhesive with high volume fraction of particle exhibits superior moisture-resistant capability. However, excessively add particles makes inferior penetrability. Therefore, adding proper volume percentage of particle into UV-curable adhesive could be expected better using in engineering applications.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"167 1","pages":"79-82"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87059826","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117204
Jung-Chang Wang, Wei-Jui Chen
The vapor chamber has been verified the excellent heat transfer efficiency and heat spreading performance utilized particularly in many high-power and small area heat sources. This paper analyzes and compares the thermal performance of a vapor chamber-based thermal module with a traditional Cu metal based plate embedded three heat pipes of 6 mm diameter at high heat flux GPU above 165 Watt. They are estimated and simulated the optimum fin design of aluminum heat sink through computational numerical method and thermal resistance analysis at constant P-Q performance curve of a same commercial blower. These results show that the total thermal resistance value of vapor chamber-based thermal module are under 0.273 °C/W from simulation analytical data and that of heat-pipes and copper based plate thermal module are all over 0.273 °C/W. Therefore, the thermal performance of vapor chamber-based thermal module can be accurately simulated and analyzed by applying the method introduced in this paper. The vapor chamber-based thermal module can achieve the optimum thermal performance and the critical heat flux may exceed 100 Watt/cm2. Consequently, the vapor chamber-based thermal module introduced in this paper is able to cope with future GPU named RV 970 and GTX 590 with high heat flux of more than 60 Watt/cm2.
{"title":"Vapor chamber in high-end VGA card","authors":"Jung-Chang Wang, Wei-Jui Chen","doi":"10.1109/IMPACT.2011.6117204","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117204","url":null,"abstract":"The vapor chamber has been verified the excellent heat transfer efficiency and heat spreading performance utilized particularly in many high-power and small area heat sources. This paper analyzes and compares the thermal performance of a vapor chamber-based thermal module with a traditional Cu metal based plate embedded three heat pipes of 6 mm diameter at high heat flux GPU above 165 Watt. They are estimated and simulated the optimum fin design of aluminum heat sink through computational numerical method and thermal resistance analysis at constant P-Q performance curve of a same commercial blower. These results show that the total thermal resistance value of vapor chamber-based thermal module are under 0.273 °C/W from simulation analytical data and that of heat-pipes and copper based plate thermal module are all over 0.273 °C/W. Therefore, the thermal performance of vapor chamber-based thermal module can be accurately simulated and analyzed by applying the method introduced in this paper. The vapor chamber-based thermal module can achieve the optimum thermal performance and the critical heat flux may exceed 100 Watt/cm2. Consequently, the vapor chamber-based thermal module introduced in this paper is able to cope with future GPU named RV 970 and GTX 590 with high heat flux of more than 60 Watt/cm2.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"105 1","pages":"393-396"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86944061","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117217
M. Hsieh, Chien-Chen Lee, Li Chiun Hung, V. Wang, Harry Perng
The pre-solder crack phenomenon after thermal cycling test is observed in 28nm extreme low-k (ELK) large die fcBGA (flip chip ball grid array), which may come from the resulted critical stresses in IMC (intermetallic compounds) on Cu pad layer. For the purpose of realizing the thermal-mechanical stress distributions in 28nm ELK large die fcBGA, a comprehensive study for the effects of package geometry is investigated by using three-dimensional finite element analyses (FEA) in this paper. The effects of under bump metallurgy (UBM) size, solder resistant opening (SRO) size, solder bump dimension, thermal interface material (TIM) thickness, Cu pad diameter, substrate thickness and its coefficient of thermal expansion (CTE) are discussed by Taguchi L16(27) methodology to figure out the most significant factors. Through the statistical results, it is found that the factors of UBM size, SRO size and Cu pad diameter had significant contributions to stress responses. The most important parameters of UBM and SRO size ratio (UBM/SRO) as well as Cu pad diameter and SRO size ratio (pad/SRO) that comprehend the corresponding stress responses are captured by using response surface methodology (RSM). To have further discussions of these significant factors, dissections for UBM, SRO and polyimide (PI) opening size are also illustrated. The simulated results can be good references and effectively served as design guidelines to avoid the critical stresses as well as enhance the reliability in 28nm ELK large die fcBGA.
{"title":"Thermo-mechanical stress analysis and optimization for 28nm extreme low-k large die fcBGA","authors":"M. Hsieh, Chien-Chen Lee, Li Chiun Hung, V. Wang, Harry Perng","doi":"10.1109/IMPACT.2011.6117217","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117217","url":null,"abstract":"The pre-solder crack phenomenon after thermal cycling test is observed in 28nm extreme low-k (ELK) large die fcBGA (flip chip ball grid array), which may come from the resulted critical stresses in IMC (intermetallic compounds) on Cu pad layer. For the purpose of realizing the thermal-mechanical stress distributions in 28nm ELK large die fcBGA, a comprehensive study for the effects of package geometry is investigated by using three-dimensional finite element analyses (FEA) in this paper. The effects of under bump metallurgy (UBM) size, solder resistant opening (SRO) size, solder bump dimension, thermal interface material (TIM) thickness, Cu pad diameter, substrate thickness and its coefficient of thermal expansion (CTE) are discussed by Taguchi L16(27) methodology to figure out the most significant factors. Through the statistical results, it is found that the factors of UBM size, SRO size and Cu pad diameter had significant contributions to stress responses. The most important parameters of UBM and SRO size ratio (UBM/SRO) as well as Cu pad diameter and SRO size ratio (pad/SRO) that comprehend the corresponding stress responses are captured by using response surface methodology (RSM). To have further discussions of these significant factors, dissections for UBM, SRO and polyimide (PI) opening size are also illustrated. The simulated results can be good references and effectively served as design guidelines to avoid the critical stresses as well as enhance the reliability in 28nm ELK large die fcBGA.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"108 1","pages":"411-414"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80719671","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117273
Ray-Hwa Wong, Mingfang Li, Ying T. Wang
In the vision based control system, the lower frame per second and the delay of image processes are main reasons to degrade the control performance. These factors have no significant influence in the low frequency material testing. In experiments, vision based electro-hydraulic material testing machine is developed by self-organizing sliding mode fuzzy controller and to carry out dynamic tracking control under 1Hz. Square, sinusoidal and triangular waveforms are applied to analyze the control performance of this electro hydraulic testing machine, and then it will discuss the feasibility of non-contacted CCD camera to replace contacted sensors.
{"title":"A vision based low-frequency electro-hydraulic fatigue testing machine","authors":"Ray-Hwa Wong, Mingfang Li, Ying T. Wang","doi":"10.1109/IMPACT.2011.6117273","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117273","url":null,"abstract":"In the vision based control system, the lower frame per second and the delay of image processes are main reasons to degrade the control performance. These factors have no significant influence in the low frequency material testing. In experiments, vision based electro-hydraulic material testing machine is developed by self-organizing sliding mode fuzzy controller and to carry out dynamic tracking control under 1Hz. Square, sinusoidal and triangular waveforms are applied to analyze the control performance of this electro hydraulic testing machine, and then it will discuss the feasibility of non-contacted CCD camera to replace contacted sensors.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"31 1","pages":"307-310"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78403623","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117291
H. Hsu, J. Chien, S. Fu
Electronic Submission Nano-mechanical properties of ultra-thin copper wire (ψ =0.6mil) and nano-tribology along the interfacial between free air ball (FAB) and aluminum bond pad were carefully investigated in this paper. For comparison, commercial product Pt-coated 99.99% (4N) Cu wire and pure 4N Cu wire are selected as test materials. Bonding temperature effects were taken into account for all case studies. Tensile mechanical properties were conducted through self-designed wire pull test fixture. Nono-indentation instrument was applied to obtained thin surface elastic modulus on FAB. Nanotribology and interfacial frictional behavior along smashed FAB and bond pad were measured by Atomic Force Microscopy (AFM). AFM force-displacement curve is utilized to determine the nanotribology properties. The interfacial coefficient of frictional force can be derived from a serial of calculations. A well-defined contact area is measured to study the frictional force and friction stress. The roughness of contact surface influences the contact between friction and surface forces. The study of roughness parameters corresponds to evaluate the friction and the interfacial strengths. Local variation in micro/nano tribology is also measured.
{"title":"A study on Nano-mechanical properties and nano-tribology for ultra-thin Pt-coated 4N copper wire","authors":"H. Hsu, J. Chien, S. Fu","doi":"10.1109/IMPACT.2011.6117291","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117291","url":null,"abstract":"Electronic Submission Nano-mechanical properties of ultra-thin copper wire (ψ =0.6mil) and nano-tribology along the interfacial between free air ball (FAB) and aluminum bond pad were carefully investigated in this paper. For comparison, commercial product Pt-coated 99.99% (4N) Cu wire and pure 4N Cu wire are selected as test materials. Bonding temperature effects were taken into account for all case studies. Tensile mechanical properties were conducted through self-designed wire pull test fixture. Nono-indentation instrument was applied to obtained thin surface elastic modulus on FAB. Nanotribology and interfacial frictional behavior along smashed FAB and bond pad were measured by Atomic Force Microscopy (AFM). AFM force-displacement curve is utilized to determine the nanotribology properties. The interfacial coefficient of frictional force can be derived from a serial of calculations. A well-defined contact area is measured to study the frictional force and friction stress. The roughness of contact surface influences the contact between friction and surface forces. The study of roughness parameters corresponds to evaluate the friction and the interfacial strengths. Local variation in micro/nano tribology is also measured.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"14 1","pages":"488-491"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80042549","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}
With the increased demand of multifunction in electronic device, downscaling of interconnection pitch presents an important role for the next generation electronics with high performance, small form factor, low cost and heterogeneous integration. In the current types of interconnects, solder micro bumps have received much attention due to its low cost of material and process. For fine pitch solder micro bump interconnections, selection of under bump metallurgical material is a crucial issue because the solder micro bump joints with different kinds of UBM material will present varied reliability performances. However, which structure of solder micro bump joint shows the better reliability properties is not concluded yet until now. In this study, three-dimensional (3D) chip stacking using 30μm pitch interconnects with lead-free solder bumps and two types of UBM material is described. The reliability of solder micro bump interconnection with varied UBM material is also discussed. Assembly of the chip-on-chip test vehicle with a micro bumps diameter of 18 μm and a pitch of 30 μm was conducted. There were more than 3000 micro bumps with Sn2.5Ag solder material on both the silicon chip and carrier. Two kinds of UBM layer on Si chip were selected in this study: one was single copper layer with a thickness of 8 μm and the other was Cu/Ni layer with a total thickness of 8 μm. The UBM was electro-plated on Al trace and then the Sn2.5Ag solder with a thickness of 5 μm was deposited. During bonding process, the micro joints were formed at a peak temperature of 250 °C and the microgaps between chips were then filled by a capillary underfill cured at 150°C for 30 min. In this study, we evaluate the effect of fluxless bonding on the joining ability of solder micro bumps. The influence of underfill on the reliability of solder micro bump interconnections was estimated also. Subsequently, the chip-stacking modules were inspected by an X-ray and a scanning acoustic microscope (SAM) to determine the quality of micro joints including bonding accuracy, formation of interconnections and the percentage of voids within the underfill. Afterwards, the moisture sensitivity level 3 pre-conditioning test and temperature cycle test for 1000 cycles were performed to evaluate the reliability of solder micro bump interconnects. The results of reliability test revealed that the introduction of underfill could apparently enhance the reliability performance of micro joint under mechanical evaluation.
{"title":"Bonding and reliability assessment of 30 μm pitch solder micro bump interconnection with various UBM structure for 3D chip stacking","authors":"Shin-Yi Huang, C. Zhan, Su-Ching Chung, Chia-Wen Fan, Su-Mei Chen, Tao-Chih Chang, Tai-Hong Chen","doi":"10.1109/IMPACT.2011.6117257","DOIUrl":"https://doi.org/10.1109/IMPACT.2011.6117257","url":null,"abstract":"With the increased demand of multifunction in electronic device, downscaling of interconnection pitch presents an important role for the next generation electronics with high performance, small form factor, low cost and heterogeneous integration. In the current types of interconnects, solder micro bumps have received much attention due to its low cost of material and process. For fine pitch solder micro bump interconnections, selection of under bump metallurgical material is a crucial issue because the solder micro bump joints with different kinds of UBM material will present varied reliability performances. However, which structure of solder micro bump joint shows the better reliability properties is not concluded yet until now. In this study, three-dimensional (3D) chip stacking using 30μm pitch interconnects with lead-free solder bumps and two types of UBM material is described. The reliability of solder micro bump interconnection with varied UBM material is also discussed. Assembly of the chip-on-chip test vehicle with a micro bumps diameter of 18 μm and a pitch of 30 μm was conducted. There were more than 3000 micro bumps with Sn2.5Ag solder material on both the silicon chip and carrier. Two kinds of UBM layer on Si chip were selected in this study: one was single copper layer with a thickness of 8 μm and the other was Cu/Ni layer with a total thickness of 8 μm. The UBM was electro-plated on Al trace and then the Sn2.5Ag solder with a thickness of 5 μm was deposited. During bonding process, the micro joints were formed at a peak temperature of 250 °C and the microgaps between chips were then filled by a capillary underfill cured at 150°C for 30 min. In this study, we evaluate the effect of fluxless bonding on the joining ability of solder micro bumps. The influence of underfill on the reliability of solder micro bump interconnections was estimated also. Subsequently, the chip-stacking modules were inspected by an X-ray and a scanning acoustic microscope (SAM) to determine the quality of micro joints including bonding accuracy, formation of interconnections and the percentage of voids within the underfill. Afterwards, the moisture sensitivity level 3 pre-conditioning test and temperature cycle test for 1000 cycles were performed to evaluate the reliability of solder micro bump interconnects. The results of reliability test revealed that the introduction of underfill could apparently enhance the reliability performance of micro joint under mechanical evaluation.","PeriodicalId":6360,"journal":{"name":"2011 6th International Microsystems, Packaging, Assembly and Circuits Technology Conference (IMPACT)","volume":"71 1","pages":"454-457"},"PeriodicalIF":0.0,"publicationDate":"2011-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90240138","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 : 2011-12-29DOI: 10.1109/IMPACT.2011.6117241
E. So, Albert Lan, C. Hsiao, Daniel Yu, Nistec Chang, F. Kao
As for mainstream portable application (Mobile Phone, Tablet, Handset Gamer), the higher density (array IO pitch <= 100um), higher thermal performance (better theta JA than overmold FCCSP) and lower profile (compare with overmold FCCSP) is necessary for package developing. As to satisfy the marketing needs, some suitable solution can be considered: Utilize Cu Pillar Bump to satisfy the fine pitch request; and also with the exposed die FCCSP to cover the lower profile & better thermal performance. As to come out an easy way to recognize the package type of this combination, the package type of “sFCCSP” (SPIL proposed FCCSP-Exposed Die Cu Pillar FCCSP) had be called for further discussion. In general, Cu Pillar was the fine pitch solution of FCCSP (<130um bump pitch), as the next generation of low IO(<200) application flip chip solution, Cu Pillar can provide a feasibility for better electrical performance but reasonable cost (design-in is necessary), and upcoming challenge is the ELK protection for 40nm / 28nm even finer IC technology. As regard the exposed die FC solution, it is obvious to realize the benefit of skipping overmold 60∼80um thickness for package total height reduction. Of course, the trade-off is either back side surface bleeding or package warpage. In this report, there is a test vehicle to show how we overcome the potential ELK crack & Die bleeding & package warpage issue to approach the mainstream technology for portable market.
对于主流便携式应用(手机、平板电脑、手机游戏)来说，更高的密度(阵列IO间距<= 100um)、更高的热性能(θ JA优于上模FCCSP)和更低的轮廓(与上模FCCSP相比)是开发封装所必需的。为了满足市场的需求，可以考虑一些合适的解决方案:利用铜柱凸点来满足细间距的要求;以及外露的FCCSP芯片，以覆盖更低的轮廓和更好的热性能。为了提出一种简单的方法来识别这种组合的封装类型，“sFCCSP”的封装类型(SPIL提议的FCCSP- exposed Die Cu Pillar FCCSP)被要求进一步讨论。总的来说，Cu柱是FCCSP (<130um凸距)的细间距解决方案，作为下一代低IO(<200)应用倒装芯片解决方案，Cu柱可以提供更好的电气性能的可行性，但成本合理(设计- In是必要的)，而即将到来的挑战是40nm / 28nm更细的IC技术的ELK保护。对于外露模FC解决方案，很明显可以实现跳过模具60 ~ 80um厚度以降低封装总高度的好处。当然，代价要么是背面表面出血，要么是包装翘曲。在本报告中，有一个测试车辆来展示我们如何克服潜在的ELK裂纹和模具出血和封装翘曲问题，以接近便携式市场的主流技术。
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