Pub Date : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245750
Cheong-Ha Jung, Won Seo, Gu-sung Kim
The IEEE Heterogeneous Integration Roadmap Symposium, held in 2018, emphasized the importance of integrating diverse components into a SiP and presented the challenges for SiP reliability. One of the problems in the reliability is a CTE(Coefficient of Thermal Expansion) mismatch between various CTE of heterogeneous materials. This mismatch issue can easily understand when we analysis a warpage in the package structure. Unlike traditional packages, FOWLP has the advantage that the substrate can be removed to achieve a thinner thickness and the thermal and electrical properties are superior to conventional packages. However, it is vulnerable to warpage due to its thin thickness and there is a problem with reliability due to cracks caused by the stress concentration of the solderball. So, to perform SiP multi-chip package with FOWLP, it is necessary to study stress-induced optimization. And we will study this through computer simulations and present guidelines.In this paper, we present an optimization solution by performing the stress analysis with the package area effect of the multi-chip FOWLP structure. In the analysis, the finite element modeling was performed on a 20X20 mm2 package approximately 200,000 elements and 90,000 nodes, simulating the Post Mold Cure of FOWLP. Because of changing the chip size, height and package / chip area ratio in order to understand the effect of the multi-chip on the package, it was confirmed that the larger the size difference among the multi chips in the package, the larger the warpage occurs. as the size of the chip became larger, the stress distribution became larger at the edge of the chip, and it was also confirmed that the larger the height difference between the multi chips, the larger the warpage occurred.
{"title":"Stress optimization study about heterogeneous multi-chip structure in Fan-out Wafer Level Package Young-in, Republic of Korea","authors":"Cheong-Ha Jung, Won Seo, Gu-sung Kim","doi":"10.1109/ICEPT47577.2019.245750","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245750","url":null,"abstract":"The IEEE Heterogeneous Integration Roadmap Symposium, held in 2018, emphasized the importance of integrating diverse components into a SiP and presented the challenges for SiP reliability. One of the problems in the reliability is a CTE(Coefficient of Thermal Expansion) mismatch between various CTE of heterogeneous materials. This mismatch issue can easily understand when we analysis a warpage in the package structure. Unlike traditional packages, FOWLP has the advantage that the substrate can be removed to achieve a thinner thickness and the thermal and electrical properties are superior to conventional packages. However, it is vulnerable to warpage due to its thin thickness and there is a problem with reliability due to cracks caused by the stress concentration of the solderball. So, to perform SiP multi-chip package with FOWLP, it is necessary to study stress-induced optimization. And we will study this through computer simulations and present guidelines.In this paper, we present an optimization solution by performing the stress analysis with the package area effect of the multi-chip FOWLP structure. In the analysis, the finite element modeling was performed on a 20X20 mm2 package approximately 200,000 elements and 90,000 nodes, simulating the Post Mold Cure of FOWLP. Because of changing the chip size, height and package / chip area ratio in order to understand the effect of the multi-chip on the package, it was confirmed that the larger the size difference among the multi chips in the package, the larger the warpage occurs. as the size of the chip became larger, the stress distribution became larger at the edge of the chip, and it was also confirmed that the larger the height difference between the multi chips, the larger the warpage occurred.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"3 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75314917","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245109
Hongyan Xu, P. Ning, Libing Zheng, Ju Xu, Shuting Zhang
This paper is devoted to study the thermal stress of a novel bondline based on Cu@Sn preform and analyze the failure mode of solder joint and SiC module. The 2D simplified model of chip-DBC substrate was created, according to the stress evaluating equations, the interfacial peel stress of chip-solder and solder-substrate was numerically calculated, and the stress distribution was imitated by ANSYS software, the results revealed that the peel stress mostly concentrated on the corners of the joint, and decreased with increased joint thickness, the peel stress could be negligible when joint thickness was greater than 50μm. Compared to the high-lead alloy system and sinter nano-silver system, the three-dimensional network structure bondline based on Cu@Sn possessed the minimum tensile stress (3MPa) and compress stress (15MPa). The multi-layer model of SiC module was built to study the influence of bondline layer thickness variation on module reliability, the result indicated that the chip stress was little dependent on the soldering layer thick, and the module stress bonded by the novel bondline was slightly larger than that of high lead system and sintered Ag system. The favorable thick bondline based on Cu@Sn preform was experimentally proved to have better mechanical strength. Shearing strength of the joint at room temperature was up to 49.5MPa, thermal cycling from -70 to 200 for 100cycles, there was no crack available on the joint, due to the pore volume got bigger, shear strength got smaller, the bondline could still function well for mechanical support.
{"title":"Investigation on thermal stress of bondline based on Cu@Sn preform at high temperature application","authors":"Hongyan Xu, P. Ning, Libing Zheng, Ju Xu, Shuting Zhang","doi":"10.1109/ICEPT47577.2019.245109","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245109","url":null,"abstract":"This paper is devoted to study the thermal stress of a novel bondline based on Cu@Sn preform and analyze the failure mode of solder joint and SiC module. The 2D simplified model of chip-DBC substrate was created, according to the stress evaluating equations, the interfacial peel stress of chip-solder and solder-substrate was numerically calculated, and the stress distribution was imitated by ANSYS software, the results revealed that the peel stress mostly concentrated on the corners of the joint, and decreased with increased joint thickness, the peel stress could be negligible when joint thickness was greater than 50μm. Compared to the high-lead alloy system and sinter nano-silver system, the three-dimensional network structure bondline based on Cu@Sn possessed the minimum tensile stress (3MPa) and compress stress (15MPa). The multi-layer model of SiC module was built to study the influence of bondline layer thickness variation on module reliability, the result indicated that the chip stress was little dependent on the soldering layer thick, and the module stress bonded by the novel bondline was slightly larger than that of high lead system and sintered Ag system. The favorable thick bondline based on Cu@Sn preform was experimentally proved to have better mechanical strength. Shearing strength of the joint at room temperature was up to 49.5MPa, thermal cycling from -70 to 200 for 100cycles, there was no crack available on the joint, due to the pore volume got bigger, shear strength got smaller, the bondline could still function well for mechanical support.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"170 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78619996","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245824
Weiming Li
Ceramic ball grid array (CBGA) solder joints were considered to crack after a series of environmental tests, including thermal cycling, random vibration and high temperature operational life test. In this paper, the failure analysis on the crack of ceramic ball grid array (CBGA) solder joints is revealed with the aid of 3D X-ray inspection, microsection technique, optical microscope (OM) and scanning electron microscope (SEM).The result of 3D X-ray shows that voids were found in the CBGA and no obvious cracks in joints were detected. By employing micro-section technique, micro-cracks were found in several CBGA solder joints with aid of OM and SEM. The result of micro-section of CBGA solder joints also reveals that the solder balls were made of eutectic tin-lead alloys. The OM and SEM images of cross-section of CBGA solder joints demonstrated that significant coarsening of solder structure was found near the cracks. In the CBGA solder joints, Pb-rich phase was well distributed into the Sn-rich. The size of Pb-rich phase in the crack area was larger than that in other area of the solder joints. As the size of microstructure increased, the interfaces between different phases decreased, which would weaken the mechanical structure of the solder joints, leading to crack failure eventually. It can be inferred that the crack of CBGA solder joints was related to thermal-mechanical fatigue. Generally, the thermal expansion of ceramic is much smaller than that of PCB substrate, which led to large thermal mismatch during the thermal cycling test, causing the thermal mechanical fatigue crack in the CBGA solder joints. The intermetallic compound (IMC) at the soldering interface and the shape of solder joints were also observed by SEM. The IMC showed a continuous morphology with proper thickness, and the solder joints kept a normal shape.In this paper, the cross section of plastic ball grid array (PBGA) solder joints on the same printed circuit board (PCB) were also observed by OM and SEM. However, no thermal mechanical fatigue cracks and coarsening of solder structure were found. It was due to that the coefficient of thermal expansion of PBGA substrate is similar to that of PCB substrate, and that the thermal mismatch between the PBGA and PCB was much smaller than that between the CBGA and PCB. Hence, thermal-mechanical fatigue cracks were found in CBGA solder joints, while the PBGA solder joints remained intact. This paper also reveals that the height of solder joint can significantly influent the reliability of the CBGA joints under the thermal cycling load.
{"title":"An analysis case on the crack failure of CBGA solder joints","authors":"Weiming Li","doi":"10.1109/ICEPT47577.2019.245824","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245824","url":null,"abstract":"Ceramic ball grid array (CBGA) solder joints were considered to crack after a series of environmental tests, including thermal cycling, random vibration and high temperature operational life test. In this paper, the failure analysis on the crack of ceramic ball grid array (CBGA) solder joints is revealed with the aid of 3D X-ray inspection, microsection technique, optical microscope (OM) and scanning electron microscope (SEM).The result of 3D X-ray shows that voids were found in the CBGA and no obvious cracks in joints were detected. By employing micro-section technique, micro-cracks were found in several CBGA solder joints with aid of OM and SEM. The result of micro-section of CBGA solder joints also reveals that the solder balls were made of eutectic tin-lead alloys. The OM and SEM images of cross-section of CBGA solder joints demonstrated that significant coarsening of solder structure was found near the cracks. In the CBGA solder joints, Pb-rich phase was well distributed into the Sn-rich. The size of Pb-rich phase in the crack area was larger than that in other area of the solder joints. As the size of microstructure increased, the interfaces between different phases decreased, which would weaken the mechanical structure of the solder joints, leading to crack failure eventually. It can be inferred that the crack of CBGA solder joints was related to thermal-mechanical fatigue. Generally, the thermal expansion of ceramic is much smaller than that of PCB substrate, which led to large thermal mismatch during the thermal cycling test, causing the thermal mechanical fatigue crack in the CBGA solder joints. The intermetallic compound (IMC) at the soldering interface and the shape of solder joints were also observed by SEM. The IMC showed a continuous morphology with proper thickness, and the solder joints kept a normal shape.In this paper, the cross section of plastic ball grid array (PBGA) solder joints on the same printed circuit board (PCB) were also observed by OM and SEM. However, no thermal mechanical fatigue cracks and coarsening of solder structure were found. It was due to that the coefficient of thermal expansion of PBGA substrate is similar to that of PCB substrate, and that the thermal mismatch between the PBGA and PCB was much smaller than that between the CBGA and PCB. Hence, thermal-mechanical fatigue cracks were found in CBGA solder joints, while the PBGA solder joints remained intact. This paper also reveals that the height of solder joint can significantly influent the reliability of the CBGA joints under the thermal cycling load.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"40 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79887764","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245261
Xingguo Fu, Shaohua Yang, Jun Luo, Si Chen, Yun Huang, Bin Zhou
Moisture is a major environmental factor that causes airtight failure under temperature cycling conditions. Increasing ambient moisture will accelerate metal-glass airtight intermittent penetration degradation. Glass insulators produce fine cracks due to reduced strength under temperature cycling conditions.Based on the molecular flow model, the formula for calculating the relationship between leak rate and crack depth and width is obtained. It is concluded that the leak rate is proportional to the cube of the crack width and inversely proportional to the micropore depth. The theoretical calculation results are less than 10% of the measured leak rate error.The moisture content converted from the liquid water of three monolayers was calculated, and the airtight HIC metal-glass sealing intermittent degradation life model with a certain leak rate was obtained.
{"title":"Study on Intermittent Penetration Degradation Life Model of Metal-Glass Sealing Structure","authors":"Xingguo Fu, Shaohua Yang, Jun Luo, Si Chen, Yun Huang, Bin Zhou","doi":"10.1109/ICEPT47577.2019.245261","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245261","url":null,"abstract":"Moisture is a major environmental factor that causes airtight failure under temperature cycling conditions. Increasing ambient moisture will accelerate metal-glass airtight intermittent penetration degradation. Glass insulators produce fine cracks due to reduced strength under temperature cycling conditions.Based on the molecular flow model, the formula for calculating the relationship between leak rate and crack depth and width is obtained. It is concluded that the leak rate is proportional to the cube of the crack width and inversely proportional to the micropore depth. The theoretical calculation results are less than 10% of the measured leak rate error.The moisture content converted from the liquid water of three monolayers was calculated, and the airtight HIC metal-glass sealing intermittent degradation life model with a certain leak rate was obtained.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"73 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77031640","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245793
Yuxiang Fu, Chunyue Huang, Chao Gao, Ying Liang
Substrate integrated waveguides (SIW) are widely used in high-speed interconnection technology and it realize high rate data transmission. In this paper, the software of HFSS is used for modeling and simulation of SIW, and the influence of SIW structure parameters on S-parameter is analyzed. Through orthogonal experimental, the main factors which affect S-parameter are obtained. The results show that S11 increases with the increase of the diameter d of the metal through-hole. S11 increases with the increase of metal through hole spacing; S11 decreases with the increase of width of SIW. Metal through hole spacing has a significant influence on S-parameter (S11), which is the main factor affecting s-parameter (S11).
{"title":"Effect of Structural Parameters of Substrate Integrated Waveguide on S-parameter Based on HFSS","authors":"Yuxiang Fu, Chunyue Huang, Chao Gao, Ying Liang","doi":"10.1109/ICEPT47577.2019.245793","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245793","url":null,"abstract":"Substrate integrated waveguides (SIW) are widely used in high-speed interconnection technology and it realize high rate data transmission. In this paper, the software of HFSS is used for modeling and simulation of SIW, and the influence of SIW structure parameters on S-parameter is analyzed. Through orthogonal experimental, the main factors which affect S-parameter are obtained. The results show that S11 increases with the increase of the diameter d of the metal through-hole. S11 increases with the increase of metal through hole spacing; S11 decreases with the increase of width of SIW. Metal through hole spacing has a significant influence on S-parameter (S11), which is the main factor affecting s-parameter (S11).","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"4 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81615401","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}
Recently, phosphor films have been widely used in display, illumination and other fields. Methods of fabricating structures on phosphor films to enhance their optical properties have attracted great attention in academia and industry. Current methods to fabricate a structured film are mainly by imprinting techniques. However, crystalline silicon or a patterned sapphire substrate are applied to the transfer substrate, which is cumbersome and expensive. This paper describes a track-etching mold, prepared by bombarding a polycarbonate film (PC) with high-speed particles to form phosphor film with microporous structure， which also has a transfer effect. The process is simple and efficient. Simultaneously, the micro-pillar structure PDMS film (MPS-PDMS film) transferred by the PC film has a discrete distribution of micro-pillar structures. Their optical performance was measured and the haze was improved by 12.06% compared with the unstructured PDMS film (US-PDMS film). Subsequently, the micro-dimples structure quantum dots film (MDS-QDs film) was secondarily fabricated using the MPS-PDMS film to have a dimple structure. The red optical power of MDS-QDs film was improved by 7.7% as compared with the unstructured quantum dot film (US-QDs film). Therefore, the structural QD films shows great potential value in luminance and display.
{"title":"Micro-dimple/pillar array molded by a track-etching mold for improving the optical performance of quantum dot film","authors":"Zongtao Li, Xueting Tang, Muwu Li, Binhai Yu, Yuling Hu, Xinrui Ding","doi":"10.1109/ICEPT47577.2019.245161","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245161","url":null,"abstract":"Recently, phosphor films have been widely used in display, illumination and other fields. Methods of fabricating structures on phosphor films to enhance their optical properties have attracted great attention in academia and industry. Current methods to fabricate a structured film are mainly by imprinting techniques. However, crystalline silicon or a patterned sapphire substrate are applied to the transfer substrate, which is cumbersome and expensive. This paper describes a track-etching mold, prepared by bombarding a polycarbonate film (PC) with high-speed particles to form phosphor film with microporous structure， which also has a transfer effect. The process is simple and efficient. Simultaneously, the micro-pillar structure PDMS film (MPS-PDMS film) transferred by the PC film has a discrete distribution of micro-pillar structures. Their optical performance was measured and the haze was improved by 12.06% compared with the unstructured PDMS film (US-PDMS film). Subsequently, the micro-dimples structure quantum dots film (MDS-QDs film) was secondarily fabricated using the MPS-PDMS film to have a dimple structure. The red optical power of MDS-QDs film was improved by 7.7% as compared with the unstructured quantum dot film (US-QDs film). Therefore, the structural QD films shows great potential value in luminance and display.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"32 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84234551","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245822
W. Yue, Jun-Xi Zhang, Chenggong Gong, Min-bo Zhou, Xin-Ping Zhang
Solder bridging is a commonly seen and serious processing defect in electronic packaging, which may lead to short circuit even absolute failure of electronic devices and products. Solder bridging may occur in all types of solder interconnects and in each of soldering processes during manufacturing journey, for example, in ball grid array solder interconnects and three-dimensional (3D) interconnects, as well as in wave soldering and reflow soldering assemblies. With the increasing trend of electronic products towards miniaturization and multifunction, the pitch and size of solder interconnects have been scaling down. The finer pitch and decreased size of solder joints greatly increase the difficulty of soldering process and the solder bridging defect is more likely to appear. Notably, the laser jet solder ball bonding (LJSBB) with the advantages of localized heating and higher energy inputting provides a novel soldering technology for 3D packaging, for instance, the right-angle solder interconnects and temperature-sensitive components. When fabricating the right-angle solder interconnects, the liquid solder ball is blown by the protected N2 flow and hardly stays firmly in place during the LJSBB process, thus the solder bridging occurs more often in the LJSBB process. Under such circumstances, it is necessary to identify the essential factors causing solder bridging of right-angle solder interconnects and seeking the improvement measures for mass production.In this study, the crucial factors causing solder bridging of right-angle Au/Sn-3.0Ag-0.5Cu/Au interconnects during LJSBB process have been investigated and identified. The results demonstrate that the poor wetting and the large displacement are the main reasons causing the solder bridging defect. The composition analysis and surface morphology characterization results manifest that the contamination of Au bonding pads and a thicker oxidation layer on the surface of solder balls significantly prolong the time of the metallurgical reaction between the solder and Au pads, which results in poor wetting of the molten solder and consequently the solder bridging defect. The verification experiments indicate that a large displacement obviously increases the waving probability of the liquid solder ball. Thus, the solder bridging defect occurs more easily. In addition, the impurities attached onto the nozzle can occasionally lead to the solder bridging defect in mass production.
{"title":"Identification of essential factors causing solder bridging of right-angle solder interconnects in laser jet solder ball bonding process","authors":"W. Yue, Jun-Xi Zhang, Chenggong Gong, Min-bo Zhou, Xin-Ping Zhang","doi":"10.1109/ICEPT47577.2019.245822","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245822","url":null,"abstract":"Solder bridging is a commonly seen and serious processing defect in electronic packaging, which may lead to short circuit even absolute failure of electronic devices and products. Solder bridging may occur in all types of solder interconnects and in each of soldering processes during manufacturing journey, for example, in ball grid array solder interconnects and three-dimensional (3D) interconnects, as well as in wave soldering and reflow soldering assemblies. With the increasing trend of electronic products towards miniaturization and multifunction, the pitch and size of solder interconnects have been scaling down. The finer pitch and decreased size of solder joints greatly increase the difficulty of soldering process and the solder bridging defect is more likely to appear. Notably, the laser jet solder ball bonding (LJSBB) with the advantages of localized heating and higher energy inputting provides a novel soldering technology for 3D packaging, for instance, the right-angle solder interconnects and temperature-sensitive components. When fabricating the right-angle solder interconnects, the liquid solder ball is blown by the protected N2 flow and hardly stays firmly in place during the LJSBB process, thus the solder bridging occurs more often in the LJSBB process. Under such circumstances, it is necessary to identify the essential factors causing solder bridging of right-angle solder interconnects and seeking the improvement measures for mass production.In this study, the crucial factors causing solder bridging of right-angle Au/Sn-3.0Ag-0.5Cu/Au interconnects during LJSBB process have been investigated and identified. The results demonstrate that the poor wetting and the large displacement are the main reasons causing the solder bridging defect. The composition analysis and surface morphology characterization results manifest that the contamination of Au bonding pads and a thicker oxidation layer on the surface of solder balls significantly prolong the time of the metallurgical reaction between the solder and Au pads, which results in poor wetting of the molten solder and consequently the solder bridging defect. The verification experiments indicate that a large displacement obviously increases the waving probability of the liquid solder ball. Thus, the solder bridging defect occurs more easily. In addition, the impurities attached onto the nozzle can occasionally lead to the solder bridging defect in mass production.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"11 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86059405","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245332
Libin Zhang, Ling Li, Yifan Wu, Yalun Suo, Z. Gan
In this article, we study the stress and defects of AlN on sapphire substrate by molecular dynamics. The temperatures and film thickness were varied to investigate the effect. We find that the mixing of film atoms with substrate atoms could be observed. As the temperature increases, the mixing of film atoms with the substrate atoms becomes more obvious. This is due to the increased kinetic energy of atoms as the temperature increases. Moreover, the fluctuation range of the average mean biaxial stress and the average normal stress mainly occur at the interface between AlN film and sapphire substrate. This is understandable because the lattice mismatch exits between AlN film and sapphire substrate, which inevitably leads to atom mismatch and involve defects and stress.
{"title":"Molecular Dynamics Simulation of Stress in AlN Thin Films on Sapphire Substrate","authors":"Libin Zhang, Ling Li, Yifan Wu, Yalun Suo, Z. Gan","doi":"10.1109/ICEPT47577.2019.245332","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245332","url":null,"abstract":"In this article, we study the stress and defects of AlN on sapphire substrate by molecular dynamics. The temperatures and film thickness were varied to investigate the effect. We find that the mixing of film atoms with substrate atoms could be observed. As the temperature increases, the mixing of film atoms with the substrate atoms becomes more obvious. This is due to the increased kinetic energy of atoms as the temperature increases. Moreover, the fluctuation range of the average mean biaxial stress and the average normal stress mainly occur at the interface between AlN film and sapphire substrate. This is understandable because the lattice mismatch exits between AlN film and sapphire substrate, which inevitably leads to atom mismatch and involve defects and stress.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"10 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89551930","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245178
He Gong, Fanfan Zhao, Yao Yao
In order to explore the mechanical and biological properties of nano-silver joints in corrosive environment, two series of experiments were carried out from the mechanical and biological perspectives. For mechanical perspectives， a) Two sandwich-like gold-plated copper (3×5×10 mm)-nano-silver-gold-plated copper (3×5×10 mm) samples were corroded for 24h in 3% NaCl solution at 45.5 ℃ (heating table temperature 50℃). The microstructural evolution of corrosion products of nano-silver sintered joints were analyzed by scanning electron microscopy (SEM). b) Twenty shear specimens were divided into two groups, corroded for 0h and 24h respectively. Besides, the corrosion shear strength of sintered nano-silver joints was measured. In order to explore the effects of nano-silver on organisms after it enters the body due to corrosion, the survival rate and apoptotic morphology of hamster lung cells were measured after incubation in nutrient solution containing 150, 175 and 200 μmol/l nano-silver for 24h. Through the above tests, it is found that the shear strength of joint decreases obviously after corrosion, and the fracture mode changes from interlayer failure to interfacial fracture. Biological experiments showed that the survival rate of hamster lung cells decreased with the increase of nano-silver concentration.
{"title":"Effect of corrosion on mechanical and biological properties of nano-silver joints","authors":"He Gong, Fanfan Zhao, Yao Yao","doi":"10.1109/ICEPT47577.2019.245178","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245178","url":null,"abstract":"In order to explore the mechanical and biological properties of nano-silver joints in corrosive environment, two series of experiments were carried out from the mechanical and biological perspectives. For mechanical perspectives， a) Two sandwich-like gold-plated copper (3×5×10 mm)-nano-silver-gold-plated copper (3×5×10 mm) samples were corroded for 24h in 3% NaCl solution at 45.5 ℃ (heating table temperature 50℃). The microstructural evolution of corrosion products of nano-silver sintered joints were analyzed by scanning electron microscopy (SEM). b) Twenty shear specimens were divided into two groups, corroded for 0h and 24h respectively. Besides, the corrosion shear strength of sintered nano-silver joints was measured. In order to explore the effects of nano-silver on organisms after it enters the body due to corrosion, the survival rate and apoptotic morphology of hamster lung cells were measured after incubation in nutrient solution containing 150, 175 and 200 μmol/l nano-silver for 24h. Through the above tests, it is found that the shear strength of joint decreases obviously after corrosion, and the fracture mode changes from interlayer failure to interfacial fracture. Biological experiments showed that the survival rate of hamster lung cells decreased with the increase of nano-silver concentration.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"46 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89636566","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 : 2019-08-01DOI: 10.1109/ICEPT47577.2019.245292
Dazheng Wang, Zhuming Liu, Libing Zheng, Wei Liu
Firstly, we describe the principle and the details of our home-built visible light-based thermoreflectance imaging setup. Based on the prototype, a transient temperature measurement of a micro resistance in operation were undertaken. With this technique, a high-resolution thermal distribution of devices can be achieved in real time. The factors influencing spatial resolution, time resolution and temperature resolution of the temperature measurement were analyzed and discussed further. The analysis and results showed that the prototype, which based on a visible light-based thermoreflectance imaging technique, could achieve a spatial resolution of 663nm, a time resolution of 2μs, and a temperature resolution of 0.1K.
{"title":"A High-resolution Thermoreflectance Imaging Technique based on Visible light","authors":"Dazheng Wang, Zhuming Liu, Libing Zheng, Wei Liu","doi":"10.1109/ICEPT47577.2019.245292","DOIUrl":"https://doi.org/10.1109/ICEPT47577.2019.245292","url":null,"abstract":"Firstly, we describe the principle and the details of our home-built visible light-based thermoreflectance imaging setup. Based on the prototype, a transient temperature measurement of a micro resistance in operation were undertaken. With this technique, a high-resolution thermal distribution of devices can be achieved in real time. The factors influencing spatial resolution, time resolution and temperature resolution of the temperature measurement were analyzed and discussed further. The analysis and results showed that the prototype, which based on a visible light-based thermoreflectance imaging technique, could achieve a spatial resolution of 663nm, a time resolution of 2μs, and a temperature resolution of 0.1K.","PeriodicalId":6676,"journal":{"name":"2019 20th International Conference on Electronic Packaging Technology(ICEPT)","volume":"266 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89062781","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：