Pub Date : 2012-11-01DOI: 10.1109/IEMT.2012.6521761
C. K. Foong, Wong Shaw Fong, Leong Jenn Seong, H. Yi, L. C. Kan, Kim Kay
Solder bridging is a common issue when surface mounting a package to motherboard. Limited studies have been conducted to understand the interaction between mold compound properties and substrate design on package coplanarity and how they relate to bridging. A recent study showed a clear influence of mold compound properties on localized unit coplanarity within a strip. The paper will also discuss both the modeling study and materials characterization effort on the fixes to prevent bridging.
{"title":"Investigation of solder bridging failure for molded matrix array package","authors":"C. K. Foong, Wong Shaw Fong, Leong Jenn Seong, H. Yi, L. C. Kan, Kim Kay","doi":"10.1109/IEMT.2012.6521761","DOIUrl":"https://doi.org/10.1109/IEMT.2012.6521761","url":null,"abstract":"Solder bridging is a common issue when surface mounting a package to motherboard. Limited studies have been conducted to understand the interaction between mold compound properties and substrate design on package coplanarity and how they relate to bridging. A recent study showed a clear influence of mold compound properties on localized unit coplanarity within a strip. The paper will also discuss both the modeling study and materials characterization effort on the fixes to prevent bridging.","PeriodicalId":315408,"journal":{"name":"2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125984187","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 : 2012-11-01DOI: 10.1109/IEMT.2012.6521762
Tan Kian Heong, Teo Chen Kim, W. Yong
Due to the high gold price, conversion from gold wire to copper wire has been a widely accepted method in semiconductor assembly for cost reduction. However, conversion from gold wire to copper wire is not a straight forward conversion. Copper wire is about 30% harder than gold wire and the commonly used bond pad metallization is Aluminium base (which is softer compare with Copper). Potential challenges include pad cratering, Al splash, lifted ball and reliability concern. Therefore, harder bond pad (plated on top of Aluminium) with Nickel as the base material was introduced. Ni which is harder than Cu, offer protection to the underlying structure, especially for probe and bond over active area products (XoAA). Technically, NiP will only bend down when the bonding impact is applied. The underneath Aluminium layer will be squashed out exhibited bond pad bending. Bond pads bend down at the centre coincide with the ball bond position and bend upward at both edges of bond pad. More severe pad bending will be observed at the direction parallel to the direction of ultra-sonic vibration and potentially cause oxide crack underneath the bond pad. Thus, the understanding of interaction between wire bond parameters and bond pad bending is very crucial to prevent oxide crack. This paper presents pad bending improvement study focusing on NiP thickness, bonding parameters and capillary design. In the stage of screening to identify the key input parameters, the results show very significant reduction on pad bending by lowering ultrasonic power. However, there is a limit for ultrasonic power in order not to compromise on the wire bond performance on non stick on pad occurrence. Thus, there is a need to consider capillary with build in design that can function with lower ultrasonic level. From experiment run, it is proven that capillary design can greatly reduce the ultrasonic power required (more than 50%) without occurrence of non stick on pad. Besides this, Ni plating thickness also shows significant impact on pad bending, a DOE approach was used to characterize and define suitable bond parameters window. A three factors (Ni plating thickness, ultrasonic power and bond force), two level factorial design was used to examine interaction and main effect. The experiment shows significant main effect by Ni plating thickness and ultrasonic power. Pad bending is less severe for lower ultrasonic power and thicker Ni plating thickness. With the defined window, XoAA device passed XoAA assessment and subsequently meet reliability requirement. Thus, it proven that this methodology is workable. In summary, Copper wire bonding on NiP based bond pad (plated on top of Al) is feasible and inline with published papers [1,2]. However, pad bending need to be considered to avoid cratering on XOAA device. Pad bending can be improved with lower ultrasonic power, capillary design and thicker Ni plating thickness. NiP plating thickness should also be included in the DOE to define suit
{"title":"Pad bending improvement on copper wire bonding on NiP/Pd/Au bond pad","authors":"Tan Kian Heong, Teo Chen Kim, W. Yong","doi":"10.1109/IEMT.2012.6521762","DOIUrl":"https://doi.org/10.1109/IEMT.2012.6521762","url":null,"abstract":"Due to the high gold price, conversion from gold wire to copper wire has been a widely accepted method in semiconductor assembly for cost reduction. However, conversion from gold wire to copper wire is not a straight forward conversion. Copper wire is about 30% harder than gold wire and the commonly used bond pad metallization is Aluminium base (which is softer compare with Copper). Potential challenges include pad cratering, Al splash, lifted ball and reliability concern. Therefore, harder bond pad (plated on top of Aluminium) with Nickel as the base material was introduced. Ni which is harder than Cu, offer protection to the underlying structure, especially for probe and bond over active area products (XoAA). Technically, NiP will only bend down when the bonding impact is applied. The underneath Aluminium layer will be squashed out exhibited bond pad bending. Bond pads bend down at the centre coincide with the ball bond position and bend upward at both edges of bond pad. More severe pad bending will be observed at the direction parallel to the direction of ultra-sonic vibration and potentially cause oxide crack underneath the bond pad. Thus, the understanding of interaction between wire bond parameters and bond pad bending is very crucial to prevent oxide crack. This paper presents pad bending improvement study focusing on NiP thickness, bonding parameters and capillary design. In the stage of screening to identify the key input parameters, the results show very significant reduction on pad bending by lowering ultrasonic power. However, there is a limit for ultrasonic power in order not to compromise on the wire bond performance on non stick on pad occurrence. Thus, there is a need to consider capillary with build in design that can function with lower ultrasonic level. From experiment run, it is proven that capillary design can greatly reduce the ultrasonic power required (more than 50%) without occurrence of non stick on pad. Besides this, Ni plating thickness also shows significant impact on pad bending, a DOE approach was used to characterize and define suitable bond parameters window. A three factors (Ni plating thickness, ultrasonic power and bond force), two level factorial design was used to examine interaction and main effect. The experiment shows significant main effect by Ni plating thickness and ultrasonic power. Pad bending is less severe for lower ultrasonic power and thicker Ni plating thickness. With the defined window, XoAA device passed XoAA assessment and subsequently meet reliability requirement. Thus, it proven that this methodology is workable. In summary, Copper wire bonding on NiP based bond pad (plated on top of Al) is feasible and inline with published papers [1,2]. However, pad bending need to be considered to avoid cratering on XOAA device. Pad bending can be improved with lower ultrasonic power, capillary design and thicker Ni plating thickness. NiP plating thickness should also be included in the DOE to define suit","PeriodicalId":315408,"journal":{"name":"2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114997672","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 : 2012-09-01DOI: 10.1109/IEMT.2012.6521824
H. Fu
Creep corrosion is a mass transport process in which solid corrosion products (typically sulfide) migrate over a surface. The corrosion product creeps onto the solder mask surface and causes short circuits between the adjacent pads and traces. Creep corrosion of electronic assemblies is a growing problem. Commonly seen in harsh environments, the failures result from the formation of copper sulfide films on Printed Circuit Board (PCB) assemblies in short period of time. The iNEMI Creep Corrosion Group working on understanding this issue has recently communicated the feasibility of simulating these corrosion signatures on electronic assemblies using a modified Mixed Flow Gas (MFG) test method. Since October 2009, iNEMI has organized phased projects to investigate creep corrosion. Phase 1 consisted of a survey to collect the data on creep corrosion failures and related factors in the electronics industry. The team also has communicating with ASHRAE, IPC 3-11g and Lawrence Berkley National Laboratory on related issues. In Phase 2, the team analyzed the output from Phase 1 and narrowed down the major factors that influenced creep corrosion. Phase 3 performs laboratory based experiments to further investigate the sensitivities of the influencing factors identified in Phase 1 and 2, including surface finish, flux, solder mask geometry, solder paste coverage, reflow and wave soldering and MFG test conditions (corrosive gas concentration, humidity, temperature). Results from the electrical resistance measurements coupled with detailed material analysis of the corrosion products will be presented in this paper.
{"title":"Investigation of factors that influence creep corrosion - iNEMI project report","authors":"H. Fu","doi":"10.1109/IEMT.2012.6521824","DOIUrl":"https://doi.org/10.1109/IEMT.2012.6521824","url":null,"abstract":"Creep corrosion is a mass transport process in which solid corrosion products (typically sulfide) migrate over a surface. The corrosion product creeps onto the solder mask surface and causes short circuits between the adjacent pads and traces. Creep corrosion of electronic assemblies is a growing problem. Commonly seen in harsh environments, the failures result from the formation of copper sulfide films on Printed Circuit Board (PCB) assemblies in short period of time. The iNEMI Creep Corrosion Group working on understanding this issue has recently communicated the feasibility of simulating these corrosion signatures on electronic assemblies using a modified Mixed Flow Gas (MFG) test method. Since October 2009, iNEMI has organized phased projects to investigate creep corrosion. Phase 1 consisted of a survey to collect the data on creep corrosion failures and related factors in the electronics industry. The team also has communicating with ASHRAE, IPC 3-11g and Lawrence Berkley National Laboratory on related issues. In Phase 2, the team analyzed the output from Phase 1 and narrowed down the major factors that influenced creep corrosion. Phase 3 performs laboratory based experiments to further investigate the sensitivities of the influencing factors identified in Phase 1 and 2, including surface finish, flux, solder mask geometry, solder paste coverage, reflow and wave soldering and MFG test conditions (corrosive gas concentration, humidity, temperature). Results from the electrical resistance measurements coupled with detailed material analysis of the corrosion products will be presented in this paper.","PeriodicalId":315408,"journal":{"name":"2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127838149","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 : 2009-10-01DOI: 10.1109/IMPACT.2009.5382241
K. Nagai, Y. Ishikawa, A. Okuno
Liquid encapsulant resin and VPES (Vacuum Printing Encapsulation Systems) process were developed for SIP included FC and passive component, etc. with solder joint. In the case of RF module, PKG size can be made thin and small in comparison with the metal cap of the conventional technology. However, such module should repeatedly reflow for mounting on the mother board. Otherwise, it will cause the problem of the solder bridge inside of PKG when it is encapsulated by resin. In consideration of this point, this resin not only dropped down the coefficient of thermal expansion and the elastic modulus simultaneously, but also improved the adhesiveness. As a result, it is able to pass the severe pre-condition. Moreover, it succeeded in molding and underfilling simultaneously by using single-species resin in VPES process. Since there is no interface between underfill material and over mold resin inside of PKG, reliability can be improved further. This paper describes the unique of over molding process by VPES, liquid resin and its reliability.
{"title":"High reliability encapsulant liquid resin for SIP","authors":"K. Nagai, Y. Ishikawa, A. Okuno","doi":"10.1109/IMPACT.2009.5382241","DOIUrl":"https://doi.org/10.1109/IMPACT.2009.5382241","url":null,"abstract":"Liquid encapsulant resin and VPES (Vacuum Printing Encapsulation Systems) process were developed for SIP included FC and passive component, etc. with solder joint. In the case of RF module, PKG size can be made thin and small in comparison with the metal cap of the conventional technology. However, such module should repeatedly reflow for mounting on the mother board. Otherwise, it will cause the problem of the solder bridge inside of PKG when it is encapsulated by resin. In consideration of this point, this resin not only dropped down the coefficient of thermal expansion and the elastic modulus simultaneously, but also improved the adhesiveness. As a result, it is able to pass the severe pre-condition. Moreover, it succeeded in molding and underfilling simultaneously by using single-species resin in VPES process. Since there is no interface between underfill material and over mold resin inside of PKG, reliability can be improved further. This paper describes the unique of over molding process by VPES, liquid resin and its reliability.","PeriodicalId":315408,"journal":{"name":"2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123639632","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 : 1900-01-01DOI: 10.1109/IEMT.2012.6521747
P. Y. Chia, A. Haseeb
Because of the miniaturization trend in electronic devices in recent years, semiconductor industry is striving hard to produce smaller and thinner devices while improving the performance and processing speed. The issue of reliability of solder joints in these miniaturized devices becomes very critical. In this study zinc is incorporated into the nickel barrier film in the form of Ni-Zn alloy by electrodeposition. The effects of the presence of Zn on the interfacial reactions between nickel barrier film and Sn-3.8Ag-0.7Cu and Sn-3.5Ag solders are investigated. Ni-Zn alloy films 1.73wt%Zn were prepared from ammoniacal diphosphate baths. Elemental composition of the alloy film was determined by energy dispersive x-ray spectroscopy (EDX) while x-ray diffraction method (XRD) was used to determine the phases present in the alloy film. Spreading rate was characterized with the use of optical microscope. Reflows were done for 1 and 12 cycles to investigate the effect of multiple reflows on the IMC growth and morphology. Results have shown that the IMC formed at the interface of SAC/Ni and SA/Ni was (Cu,Ni)5Sn6 and Ni3Sn4 respectively. (Ni,Cu)3Sn4 IMC was formed at the interface of SA/Ni-Zn alloy film. No spalling was detected at the SA/Ni-Zn solder joint. On the other hand, it has been observed that (Ni,Cu)3Sn4 and (Cu,Ni)6Sn5 layer with continuous non-uniform morphology were formed on the SAC/Ni-Zn alloy film after 1x reflow. As the number of reflow increased, (Cu,Ni)6Sn5 layer spalled from the interface leaving only (Ni,Cu)3Sn4 IMC at the interfacial region.
{"title":"Interfacial reactions between Ni-Zn alloy films and lead-free solders","authors":"P. Y. Chia, A. Haseeb","doi":"10.1109/IEMT.2012.6521747","DOIUrl":"https://doi.org/10.1109/IEMT.2012.6521747","url":null,"abstract":"Because of the miniaturization trend in electronic devices in recent years, semiconductor industry is striving hard to produce smaller and thinner devices while improving the performance and processing speed. The issue of reliability of solder joints in these miniaturized devices becomes very critical. In this study zinc is incorporated into the nickel barrier film in the form of Ni-Zn alloy by electrodeposition. The effects of the presence of Zn on the interfacial reactions between nickel barrier film and Sn-3.8Ag-0.7Cu and Sn-3.5Ag solders are investigated. Ni-Zn alloy films 1.73wt%Zn were prepared from ammoniacal diphosphate baths. Elemental composition of the alloy film was determined by energy dispersive x-ray spectroscopy (EDX) while x-ray diffraction method (XRD) was used to determine the phases present in the alloy film. Spreading rate was characterized with the use of optical microscope. Reflows were done for 1 and 12 cycles to investigate the effect of multiple reflows on the IMC growth and morphology. Results have shown that the IMC formed at the interface of SAC/Ni and SA/Ni was (Cu,Ni)5Sn6 and Ni3Sn4 respectively. (Ni,Cu)3Sn4 IMC was formed at the interface of SA/Ni-Zn alloy film. No spalling was detected at the SA/Ni-Zn solder joint. On the other hand, it has been observed that (Ni,Cu)3Sn4 and (Cu,Ni)6Sn5 layer with continuous non-uniform morphology were formed on the SAC/Ni-Zn alloy film after 1x reflow. As the number of reflow increased, (Cu,Ni)6Sn5 layer spalled from the interface leaving only (Ni,Cu)3Sn4 IMC at the interfacial region.","PeriodicalId":315408,"journal":{"name":"2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115722614","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 : 1900-01-01DOI: 10.1109/iemt.2012.6521782
Summary form only given. In this study, miniature solder joint behaviors of Sn3.8Ag0.7Cu (SAC387) solder were tested and discussed for a range of geometrical ratios and strain rates at room temperature. Copper-solder-copper rod specimens were machined and soldered with SAC387 based on their specified geometrical ratio and then tested with an uni-axial load at a constant strain rate of 0.01s-1. Orowan's approximation equation was used to make comparison with experimental results, followed by comparison of experimental results with the Finite Element Analysis (FEA) results. It was observed that variation of the geometrical ratio induced the formation of the dimensional constraining effect within the material. To study strain rate effect on copper-solder-copper joint, specimens with specified dimensions were tested with an uni-axial load at varying strain rate of 0.001s-1, 0.01s-1 and 0.1s-1. Comparisons were conducted between the experimental and FEA simulated results. The increment in either the geometrical ratio of the solder or strain rate experienced within the joint was both noticed to lead to the deterioration of ductility but a simultaneous improvement in the brittle characteristic of the material.
{"title":"Size and strain effect on miniature copper-solder-copper joint","authors":"","doi":"10.1109/iemt.2012.6521782","DOIUrl":"https://doi.org/10.1109/iemt.2012.6521782","url":null,"abstract":"Summary form only given. In this study, miniature solder joint behaviors of Sn3.8Ag0.7Cu (SAC387) solder were tested and discussed for a range of geometrical ratios and strain rates at room temperature. Copper-solder-copper rod specimens were machined and soldered with SAC387 based on their specified geometrical ratio and then tested with an uni-axial load at a constant strain rate of 0.01s-1. Orowan's approximation equation was used to make comparison with experimental results, followed by comparison of experimental results with the Finite Element Analysis (FEA) results. It was observed that variation of the geometrical ratio induced the formation of the dimensional constraining effect within the material. To study strain rate effect on copper-solder-copper joint, specimens with specified dimensions were tested with an uni-axial load at varying strain rate of 0.001s-1, 0.01s-1 and 0.1s-1. Comparisons were conducted between the experimental and FEA simulated results. The increment in either the geometrical ratio of the solder or strain rate experienced within the joint was both noticed to lead to the deterioration of ductility but a simultaneous improvement in the brittle characteristic of the material.","PeriodicalId":315408,"journal":{"name":"2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123302974","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 : 1900-01-01DOI: 10.1109/IEMT.2012.6521748
Y. M. Leong, A. Haseeb
Driven by the necessity to improve the reliability of lead free electronic products and by the trend towards miniaturization, researchers are putting intense efforts to improve the properties of Sn based solders. One of the current approaches to improve the properties of Sn based solder is to add nanoparticles. A number of studies have been done on the effects of the addition of nanoparticles on the interfacial intermetallic compound (IMC) characteristics [1-3]. It has been found that the additions of Ni [1], Co [1,2] and Mo [3] nanoparticles substantially influence the characteristics of interfacial intermetallic compounds.The present work investigates the effects of Zn nanoparticles (up to 0.34%) on the melting point, wetting characteristics and interfacial structure between Sn-3.5Ag (SA) solder and copper substrate during reflow. The melting characteristics of nanocomposite solders were investigated by differential scanning calorimetry (DSC). The actual Zn content of the solder after reflow was determined by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The wetting angle and spreading rate were measured to investigate the solderability of nancomposite solder. High resolution field emission scanning electron microscopy (FESEM) was used to investigate the morphology of IMC formation at the solder/substrate interface during reflow. Results showed that addition of Zn nanoparticles suppressed the melting point of the solder. The wetting angle of the solder increased, while the spreading rate decreased with the addition of Zn nanoparticles. Cross sectional microscopy revealed that the typical scallop type Cu6Sn5 and a very thin, flat Cu3Sn formed in SA after 1x and 6x reflows. The addition of Zn nanoparticles substantially suppressed the growth of the interfacial IMCs. Addition of Zn has also suppresed the formation of Cu3Sn significantly during aging. The mechanism of the influence of Zn nanoparticles is discussed.
{"title":"Soldering and interfacial characteristics of Sn-3.5Ag solder containing zinc nanoparticles","authors":"Y. M. Leong, A. Haseeb","doi":"10.1109/IEMT.2012.6521748","DOIUrl":"https://doi.org/10.1109/IEMT.2012.6521748","url":null,"abstract":"Driven by the necessity to improve the reliability of lead free electronic products and by the trend towards miniaturization, researchers are putting intense efforts to improve the properties of Sn based solders. One of the current approaches to improve the properties of Sn based solder is to add nanoparticles. A number of studies have been done on the effects of the addition of nanoparticles on the interfacial intermetallic compound (IMC) characteristics [1-3]. It has been found that the additions of Ni [1], Co [1,2] and Mo [3] nanoparticles substantially influence the characteristics of interfacial intermetallic compounds.The present work investigates the effects of Zn nanoparticles (up to 0.34%) on the melting point, wetting characteristics and interfacial structure between Sn-3.5Ag (SA) solder and copper substrate during reflow. The melting characteristics of nanocomposite solders were investigated by differential scanning calorimetry (DSC). The actual Zn content of the solder after reflow was determined by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). The wetting angle and spreading rate were measured to investigate the solderability of nancomposite solder. High resolution field emission scanning electron microscopy (FESEM) was used to investigate the morphology of IMC formation at the solder/substrate interface during reflow. Results showed that addition of Zn nanoparticles suppressed the melting point of the solder. The wetting angle of the solder increased, while the spreading rate decreased with the addition of Zn nanoparticles. Cross sectional microscopy revealed that the typical scallop type Cu6Sn5 and a very thin, flat Cu3Sn formed in SA after 1x and 6x reflows. The addition of Zn nanoparticles substantially suppressed the growth of the interfacial IMCs. Addition of Zn has also suppresed the formation of Cu3Sn significantly during aging. The mechanism of the influence of Zn nanoparticles is discussed.","PeriodicalId":315408,"journal":{"name":"2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130612943","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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