GTA welding is a representative welding technique applied to root pass welding of piping. The pipe root pass welding significantly influences the determination of welding parameters owing to the root gap and step change occurring during installation. GTA welding has the advantage of being able to control current (A) and wire feeding speed (WFS) as independent variables; however, determining these variables is difficult. In this study, the change in the back bead height (Bbh) was observed by changing the root gap and WFS while the welding speed and welding current (A) were fixed. By fixing the welding speed and changing the welding current (A), root gap, and WFS, the gap bridging possible condition was expressed as a region. When the root gap changed from 0~1 mm and from 1~2 mm, the back bead height was greater than or equal to 0 mm. Possible welding current and WFS and the setting range of the welding heat input ratio (HIR) were presented.
{"title":"A Study on Gap Bridging Formation Conditions in Butt Root Pass Welding Using GTAW","authors":"Daekyu Park, Changsub Song, Youngwhan Park","doi":"10.5781/jwj.2023.41.5.3","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.3","url":null,"abstract":"GTA welding is a representative welding technique applied to root pass welding of piping. The pipe root pass welding significantly influences the determination of welding parameters owing to the root gap and step change occurring during installation. GTA welding has the advantage of being able to control current (A) and wire feeding speed (WFS) as independent variables; however, determining these variables is difficult. In this study, the change in the back bead height (Bbh) was observed by changing the root gap and WFS while the welding speed and welding current (A) were fixed. By fixing the welding speed and changing the welding current (A), root gap, and WFS, the gap bridging possible condition was expressed as a region. When the root gap changed from 0~1 mm and from 1~2 mm, the back bead height was greater than or equal to 0 mm. Possible welding current and WFS and the setting range of the welding heat input ratio (HIR) were presented.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"43 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929461","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}
Matthew Criado, Abhijit Roy, John Ohodnicki, Nicholas Tondravi, Hannah Fischer, Alejandro Almarza, Howard A. Kuhn, Prashant N. Kumta
Methods to optimize the diffusion bonding (DB) process while also creating lap joints were investigated using AZ31, the commercial Mg alloy, focusing primarily on studying the effects of varying conventional process parameters and more importantly, exploring the influence of surface roughness on creating an acceptable strong bond. The results indicate that when contact is made between surface areas of roughness (Ra > 0.2 ㎛) diffusion is facilitated at reduced process parameters of time and temperature. Furthermore, this early bond initiation combined with the optimized DB process parameters results in a stronger bond with strengths increasing by ~ 150% in comparison to the DB samples created with a smooth surface finish. Additionally, less than 20% total overall distortion is observed while preserving a uniform microstructure of consistent grain sizes in the material over the entire joining region compared with the parent material.
以AZ31(商用镁合金)为材料，研究了优化扩散键合(DB)工艺的方法，同时建立了接箍，主要研究了不同常规工艺参数的影响，更重要的是，探索了表面粗糙度对建立可接受的强键合的影响。结果表明，当粗糙度(Ra >在降低时间和温度的工艺参数下，有利于0.2 μ m (um)的扩散。此外，与光滑表面处理的DB样品相比，这种早期键合启动与优化的DB工艺参数相结合，导致更强的键合强度增加了约150%。此外，与母材相比，在整个连接区域保持材料晶粒尺寸一致的均匀微观结构的同时，观察到的总总畸变小于20%。
{"title":"Understanding the Effects of Surface Finish on Diffusion Bonding of AZ31 Alloys","authors":"Matthew Criado, Abhijit Roy, John Ohodnicki, Nicholas Tondravi, Hannah Fischer, Alejandro Almarza, Howard A. Kuhn, Prashant N. Kumta","doi":"10.5781/jwj.2023.41.5.1","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.1","url":null,"abstract":"Methods to optimize the diffusion bonding (DB) process while also creating lap joints were investigated using AZ31, the commercial Mg alloy, focusing primarily on studying the effects of varying conventional process parameters and more importantly, exploring the influence of surface roughness on creating an acceptable strong bond. The results indicate that when contact is made between surface areas of roughness (Ra > 0.2 ㎛) diffusion is facilitated at reduced process parameters of time and temperature. Furthermore, this early bond initiation combined with the optimized DB process parameters results in a stronger bond with strengths increasing by ~ 150% in comparison to the DB samples created with a smooth surface finish. Additionally, less than 20% total overall distortion is observed while preserving a uniform microstructure of consistent grain sizes in the material over the entire joining region compared with the parent material.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"149 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929640","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}
Laser welding is increasingly used in industries because it allows high production cycle time and single-sided welding, but is characterized by a high sensitivity to joint preparation. By inserting filler wires, the sensitivity to joint preparation can be suppressed. In this study, the effect of welding variables on the bead geometry and melted droplet transfer were investigated. Two wires with different thermal diffusivities and densities were selected: stainless steel (STS) and aluminum (Al) wires. According to the wire feeding angle, the melting area tended to differ between the STS and Al wires. This implied that the wire feeding angle had to consider the absorption rate of the material for the laser wavelength. With an increase in the distance between the wire tip and the substrate, the dominant force acting on the droplet was changed from surface tension to gravity. Therefore, the distance was considered as a major factor in determining the droplet transfer mode. In all cases, the droplet transfer period exhibited relatively small deviation when the wire feeding direction was leading. Furthermore, the focal length effects on droplet transfer were irrelevant.
{"title":"Effects of Welding Parameters on Droplet Transfer and Bead Geometry in Laser Welding with Aluminum and Stainless Steel Filler Wires","authors":"Joonghyeon Shin, Seung Hwan Lee, Minjung Kang","doi":"10.5781/jwj.2023.41.5.4","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.4","url":null,"abstract":"Laser welding is increasingly used in industries because it allows high production cycle time and single-sided welding, but is characterized by a high sensitivity to joint preparation. By inserting filler wires, the sensitivity to joint preparation can be suppressed. In this study, the effect of welding variables on the bead geometry and melted droplet transfer were investigated. Two wires with different thermal diffusivities and densities were selected: stainless steel (STS) and aluminum (Al) wires. According to the wire feeding angle, the melting area tended to differ between the STS and Al wires. This implied that the wire feeding angle had to consider the absorption rate of the material for the laser wavelength. With an increase in the distance between the wire tip and the substrate, the dominant force acting on the droplet was changed from surface tension to gravity. Therefore, the distance was considered as a major factor in determining the droplet transfer mode. In all cases, the droplet transfer period exhibited relatively small deviation when the wire feeding direction was leading. Furthermore, the focal length effects on droplet transfer were irrelevant.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929455","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}
Jae-Hyeon Park, Myung-Jin Kim, Heeshin Kang, Wonah Park, Eun-Joon Chun
Solidification cracking during lithium-ion battery packaging was metallurgically investigated, specifically for Cu-steel dissimilar materials. To this end, single-mode fiber and green lasers were employed under heat input conditions ranging from 1.3 to 8.0 J/mm. For both laser welds, solidification cracking was concentrated in the steel region of the fusion zone, particularly in the locally Cu-depleted region, regardless of the welding condition. Modified self-restraint tests were performed for overlapping dissimilar material combinations to elucidate the mechanism of solidification cracking. Analysis of the solidification cracking surface revealed that approximately 15?30 mass% Cu existed on the surface. Cu was highly enriched with a droplet shape, formed during solidification within the miscibility gap. By calculating the non-equilibrium weld mushy zone range based on the diffusion-controlled Scheil’s model, the solidification cracking in the Cu-depleted region was estimated at 453 K. It was strongly affected by the severe segregation of Cu (95.7 mass%) in the residual liquid at the terminal stage of the solidification path. Therefore, from a welding metallurgical perspective, homogeneous Cu distribution and minimization of Cu segregation within the fusion zone are essential for suppressing or minimizing the solidification cracking susceptibility of Cu?steel dissimilar laser welding.
{"title":"Hot Cracking Characteristics During Single-Mode Fiber and Green Laser Welding Processes in Lithium-Ion Battery Pack Manufacturing","authors":"Jae-Hyeon Park, Myung-Jin Kim, Heeshin Kang, Wonah Park, Eun-Joon Chun","doi":"10.5781/jwj.2023.41.5.7","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.7","url":null,"abstract":"Solidification cracking during lithium-ion battery packaging was metallurgically investigated, specifically for Cu-steel dissimilar materials. To this end, single-mode fiber and green lasers were employed under heat input conditions ranging from 1.3 to 8.0 J/mm. For both laser welds, solidification cracking was concentrated in the steel region of the fusion zone, particularly in the locally Cu-depleted region, regardless of the welding condition. Modified self-restraint tests were performed for overlapping dissimilar material combinations to elucidate the mechanism of solidification cracking. Analysis of the solidification cracking surface revealed that approximately 15?30 mass% Cu existed on the surface. Cu was highly enriched with a droplet shape, formed during solidification within the miscibility gap. By calculating the non-equilibrium weld mushy zone range based on the diffusion-controlled Scheil’s model, the solidification cracking in the Cu-depleted region was estimated at 453 K. It was strongly affected by the severe segregation of Cu (95.7 mass%) in the residual liquid at the terminal stage of the solidification path. Therefore, from a welding metallurgical perspective, homogeneous Cu distribution and minimization of Cu segregation within the fusion zone are essential for suppressing or minimizing the solidification cracking susceptibility of Cu?steel dissimilar laser welding.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929451","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 : 2023-10-31DOI: 10.5781/jwj.2023.41.5.10
Jun-Seok Park, Joo-Shin Park, Jung-Kwan Seo
Recently, the amount of orders for large container ships based on eco-friendly fuel is increasing. Container ships have very different characteristics of cargo as comparing other type cargo carriers, having a unique arrangement of structural members. In this reason, the classification societies propose major governing conditions that affect independent shaft alignment calculations based on detailed analysis. In this study, the change in displacement around the shaft system, which occurs in the manufacturing process, was investigated using structural analysis modeling. The manufacturing process is divided into PE (Pre-erection), welding according to the erection sequences, lifting the block, setting on the dock, and finally reviewing the launching conditions. The results of this study, the displacement of the shaft system during the manufacturing stages were confirmed. The change in the number of block supports had the greatest effect on the change in deflection rather than the effect of welding heat, and the final results were similar to those of the PE condition. The shaft centering analysis can be predicted correct value in advance if the characteristics of deflection change according to the process are known, and accurate prediction can be made in a short time by using the proposed procedure.
{"title":"A Study on the Characteristics about Shaft Deflection According to the Change in Manufacturing Sequences","authors":"Jun-Seok Park, Joo-Shin Park, Jung-Kwan Seo","doi":"10.5781/jwj.2023.41.5.10","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.10","url":null,"abstract":"Recently, the amount of orders for large container ships based on eco-friendly fuel is increasing. Container ships have very different characteristics of cargo as comparing other type cargo carriers, having a unique arrangement of structural members. In this reason, the classification societies propose major governing conditions that affect independent shaft alignment calculations based on detailed analysis. In this study, the change in displacement around the shaft system, which occurs in the manufacturing process, was investigated using structural analysis modeling. The manufacturing process is divided into PE (Pre-erection), welding according to the erection sequences, lifting the block, setting on the dock, and finally reviewing the launching conditions. The results of this study, the displacement of the shaft system during the manufacturing stages were confirmed. The change in the number of block supports had the greatest effect on the change in deflection rather than the effect of welding heat, and the final results were similar to those of the PE condition. The shaft centering analysis can be predicted correct value in advance if the characteristics of deflection change according to the process are known, and accurate prediction can be made in a short time by using the proposed procedure.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"20 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929452","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}
Seong hyun Kim, Jae-Deuk Kim, Hyun-Uk Jun, Joo Yong Cheon, Seungjong Yun, Yangdo Kim, Changwook Ji
It is expected that the application of aluminum alloy, a lightweight material, will continue to increase in connection with strengthening international environmental regulations and improving fuel efficiency for reducing vehicle emissions. Accordingly, aluminum alloys are widely applied to the automobile industry, and various welding methods are used for aluminum alloys. In this paper, the laser-arc hybrid welding method that combines laser and arc welding is explained. Although laser-arc hybrid welding has better weldability than a single heat source of laser or arc, the degradation of mechanical properties due to defects occurring during hybrid welding has emerged as a problem. This paper discussed the quality of aluminum alloy welds through optimization of various process parameters of hybrid welding.
{"title":"A Review on Effects of Weld Porosity in Laser-Arc Hybrid Welding for Aluminum Alloys","authors":"Seong hyun Kim, Jae-Deuk Kim, Hyun-Uk Jun, Joo Yong Cheon, Seungjong Yun, Yangdo Kim, Changwook Ji","doi":"10.5781/jwj.2023.41.5.6","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.6","url":null,"abstract":"It is expected that the application of aluminum alloy, a lightweight material, will continue to increase in connection with strengthening international environmental regulations and improving fuel efficiency for reducing vehicle emissions. Accordingly, aluminum alloys are widely applied to the automobile industry, and various welding methods are used for aluminum alloys. In this paper, the laser-arc hybrid welding method that combines laser and arc welding is explained. Although laser-arc hybrid welding has better weldability than a single heat source of laser or arc, the degradation of mechanical properties due to defects occurring during hybrid welding has emerged as a problem. This paper discussed the quality of aluminum alloy welds through optimization of various process parameters of hybrid welding.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929456","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}
Joo Young Bae, Mi-Song Kim, Hye Min Lee, Seul Gi Lee, Young-Woo Lee, Jeong Tak Moon, Won Sik Hong
Alloying effects of Nickel and Bismuth in SAC solder to achieve mechanical and microstructural evolution were investigated by comparing three different chemical composition of solders. Sn-3.0Ag-0.5Cu (SAC305) is the most commonly used for Pb-free solder and solder balls are based on Sn-Ag-Cu alloy composition. Compositions of solder balls were Sn-3.0Ag-0.5Cu (SAC305), Sn-1.2Ag-0.5Cu-0.05Ni (SAC1205N) and Sn-Ag-Cu-Ni-Bi based solder (SACNB). Organic solderability preservative (OSP) surface finished substrate, ball grid array (BGA) package arranged by 300 ㎛ diameter solder ball and Type 4 solder paste were used. Solder ball shear test of the BGA package was conducted before the reflow soldering. Board level package bonding process was carried out by hot air reflow soldering. Void content of the BGA solder joint was investigated after soldering. The microstructure evolution before and after thermal cycle test (TCT) was observed using scanning eletron microscopy (SEM) and energy dispersive spectroscopy (EDS). After TCT, intermetallic compound (IMC) refinement and solid solution strengthening effects of Bi element addition were observed in the solder matrix, and also any segregation of Bi element was not founded. Based on these result, it was found that the solder joint reliability of the middle and low temperature solder joints was improved.
{"title":"Bonding Property of Middle Temperature Sn-Ag-Cu Solder Ball Joint of Ball Grid Array Package","authors":"Joo Young Bae, Mi-Song Kim, Hye Min Lee, Seul Gi Lee, Young-Woo Lee, Jeong Tak Moon, Won Sik Hong","doi":"10.5781/jwj.2023.41.5.8","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.8","url":null,"abstract":"Alloying effects of Nickel and Bismuth in SAC solder to achieve mechanical and microstructural evolution were investigated by comparing three different chemical composition of solders. Sn-3.0Ag-0.5Cu (SAC305) is the most commonly used for Pb-free solder and solder balls are based on Sn-Ag-Cu alloy composition. Compositions of solder balls were Sn-3.0Ag-0.5Cu (SAC305), Sn-1.2Ag-0.5Cu-0.05Ni (SAC1205N) and Sn-Ag-Cu-Ni-Bi based solder (SACNB). Organic solderability preservative (OSP) surface finished substrate, ball grid array (BGA) package arranged by 300 ㎛ diameter solder ball and Type 4 solder paste were used. Solder ball shear test of the BGA package was conducted before the reflow soldering. Board level package bonding process was carried out by hot air reflow soldering. Void content of the BGA solder joint was investigated after soldering. The microstructure evolution before and after thermal cycle test (TCT) was observed using scanning eletron microscopy (SEM) and energy dispersive spectroscopy (EDS). After TCT, intermetallic compound (IMC) refinement and solid solution strengthening effects of Bi element addition were observed in the solder matrix, and also any segregation of Bi element was not founded. Based on these result, it was found that the solder joint reliability of the middle and low temperature solder joints was improved.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929449","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}
Changhoon Lee, Dong-Yoon Kim, Jason Cheon, Jiyoung Yu
This study proposes a method to predict tensile shear strength of the overlap welded joint of aluminum alloy (Al5083-O, Al6061-T5) plates applied to the cowl-cross part of a vehicle. The profile of a weld bead was measured using a laser vision sensor, and a technology that can predict tensile shear strength of a welded joint was developed and evaluated. Welded joints were fabricated by using AC pulse GMAW to overlap the configuration of the aluminum alloy plates. The data required for training the prediction model were obtained by measuring the profiles of the welded joints using a laser vision sensor and conducting a tensile test. A CNN-based regression model was thus developed to predict tensile shear strength of welded joints. The model uses a weld?bead profile and material information as input and estimates tensile shear strength of a welded joint as output. The average prediction error of the proposed model was calculated to be approximately 3%.
{"title":"Prediction Model for Tensile Shear Strength of Gas Metal Arc Weld using a Laser Vision Sensor","authors":"Changhoon Lee, Dong-Yoon Kim, Jason Cheon, Jiyoung Yu","doi":"10.5781/jwj.2023.41.5.5","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.5","url":null,"abstract":"This study proposes a method to predict tensile shear strength of the overlap welded joint of aluminum alloy (Al5083-O, Al6061-T5) plates applied to the cowl-cross part of a vehicle. The profile of a weld bead was measured using a laser vision sensor, and a technology that can predict tensile shear strength of a welded joint was developed and evaluated. Welded joints were fabricated by using AC pulse GMAW to overlap the configuration of the aluminum alloy plates. The data required for training the prediction model were obtained by measuring the profiles of the welded joints using a laser vision sensor and conducting a tensile test. A CNN-based regression model was thus developed to predict tensile shear strength of welded joints. The model uses a weld?bead profile and material information as input and estimates tensile shear strength of a welded joint as output. The average prediction error of the proposed model was calculated to be approximately 3%.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"22 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929450","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}
So-Hee Hyun, Hye Min Lee, Mi-Song Kim, Won Sik Hong
The package-on-package technology has been developed to facilitate high-density integration of semiconductor packaging. As the solder bump pitch is decreased, the void content in solder bump joints increases, thereby decreasing its reliability. Consequently, vacuum reflow (VR) is used to increase void fluidity and decrease void content in micro bump joints. Generally, silicon chips in application processor modules are bonded using thermal compression (TC) bonding, followed by the attachment of passive components through hot air reflow soldering. However, the simultaneous bonding of Si chips and passive components using VR can improve productivity.In this study, we performed TC and VR bonding without additional solder pastes, between an Si chip with a Cu pillar/Sn-2.5Ag bump and a bismaleimide triazine substrate plated with electroless-nickel electroless-palladium immersion-gold. It was observed that the void content at the Si chip solder joints yielded by VR (10.8%) was similar to that yielded by TC (11.2%). Furthermore, the Si chip solder joint of the VR sample was thicker than that of the TC sample. This process also resulted in the formation of the intermetallic compounds Cu6Sn5, (Cu,Ni)6Sn5, Ag3Sn, and Ni3P, at the Si chip solder joints. The results of this study suggest that co-bonding of active and passive components is possible through VR soldering for semiconductor packaging.
{"title":"Bonding Property of Flip-Chip Chip-Scale Package with Vacuum Reflow and Thermal Compression Bonding Processes","authors":"So-Hee Hyun, Hye Min Lee, Mi-Song Kim, Won Sik Hong","doi":"10.5781/jwj.2023.41.5.9","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.9","url":null,"abstract":"The package-on-package technology has been developed to facilitate high-density integration of semiconductor packaging. As the solder bump pitch is decreased, the void content in solder bump joints increases, thereby decreasing its reliability. Consequently, vacuum reflow (VR) is used to increase void fluidity and decrease void content in micro bump joints. Generally, silicon chips in application processor modules are bonded using thermal compression (TC) bonding, followed by the attachment of passive components through hot air reflow soldering. However, the simultaneous bonding of Si chips and passive components using VR can improve productivity.In this study, we performed TC and VR bonding without additional solder pastes, between an Si chip with a Cu pillar/Sn-2.5Ag bump and a bismaleimide triazine substrate plated with electroless-nickel electroless-palladium immersion-gold. It was observed that the void content at the Si chip solder joints yielded by VR (10.8%) was similar to that yielded by TC (11.2%). Furthermore, the Si chip solder joint of the VR sample was thicker than that of the TC sample. This process also resulted in the formation of the intermetallic compounds Cu<sub>6</sub>Sn<sub>5</sub>, (Cu,Ni)<sub>6</sub>Sn<sub>5</sub>, Ag<sub>3</sub>Sn, and Ni<sub>3</sub>P, at the Si chip solder joints. The results of this study suggest that co-bonding of active and passive components is possible through VR soldering for semiconductor packaging.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929454","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}
Essential requirements for weld seams are the long-term transmission of static and time-varying forces. Requirements for the verification of laser welded fillet weld T-joints are proposed in this paper, since there is no established procedure in this field for laser welding. More precisely, the strength of laser MIG hybrid welded AlMg3Mn T-joints, made from 3.5 mm thick sheet metal are determined, depending on the penetration of their weld root gap. This allowed the unwelded root gap to be related to the decrease in strength, even though this is more apparent with dynamic than with static loading. In addition, the influence of filler material, single and mutual-sided MIG welds have been added to this comparison. Filler materials used are the related AlMg2.7Mn or the extraneous AlSi5.
{"title":"Strength Evaluation of Welded Aluminum T-joints, as a Function of Its Welding Process, Execution, Filler Material, and Weld Root Penetration","authors":"Johannes Gaigl","doi":"10.5781/jwj.2023.41.5.2","DOIUrl":"https://doi.org/10.5781/jwj.2023.41.5.2","url":null,"abstract":"Essential requirements for weld seams are the long-term transmission of static and time-varying forces. Requirements for the verification of laser welded fillet weld T-joints are proposed in this paper, since there is no established procedure in this field for laser welding. More precisely, the strength of laser MIG hybrid welded AlMg3Mn T-joints, made from 3.5 mm thick sheet metal are determined, depending on the penetration of their weld root gap. This allowed the unwelded root gap to be related to the decrease in strength, even though this is more apparent with dynamic than with static loading. In addition, the influence of filler material, single and mutual-sided MIG welds have been added to this comparison. Filler materials used are the related AlMg2.7Mn or the extraneous AlSi5.","PeriodicalId":490600,"journal":{"name":"Journal of welding and joining (Online)","volume":"48 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135929459","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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