Subjects -> METALLURGY (Total: 58 journals)
Showing 1 - 10 of 10 Journals sorted alphabetically
Acta Metallurgica Slovaca     Open Access  
Advanced Device Materials     Open Access   (Followers: 3)
American Journal of Fluid Dynamics     Open Access   (Followers: 48)
Archives of Metallurgy and Materials     Open Access   (Followers: 9)
Asian Journal of Materials Science     Open Access   (Followers: 5)
Canadian Metallurgical Quarterly     Hybrid Journal   (Followers: 20)
Complex Metals     Open Access   (Followers: 2)
Corrosion Communications     Open Access  
Energy Materials : Materials Science and Engineering for Energy Systems     Hybrid Journal   (Followers: 19)
Handbook of Magnetic Materials     Full-text available via subscription   (Followers: 2)
Indian Journal of Engineering and Materials Sciences (IJEMS)     Open Access   (Followers: 10)
International Journal of Metallurgy and Alloys     Full-text available via subscription   (Followers: 3)
International Journal of Metals     Open Access   (Followers: 6)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 8)
International Journal of Mining and Geo-Engineering     Open Access  
Ironmaking & Steelmaking     Hybrid Journal   (Followers: 4)
ISIJ International - Iron and Steel Institute of Japan     Full-text available via subscription   (Followers: 23)
JOM Journal of the Minerals, Metals and Materials Society     Hybrid Journal   (Followers: 32)
Journal of Advanced Joining Processes     Open Access  
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of Cluster Science     Hybrid Journal  
Journal of Iron and Steel Research International     Hybrid Journal   (Followers: 7)
Journal of Materials & Metallurgical Engineering     Full-text available via subscription   (Followers: 1)
Journal of Materials Processing Technology     Hybrid Journal   (Followers: 19)
Journal of Metallurgical Engineering     Open Access   (Followers: 2)
Journal of Sustainable Metallurgy     Hybrid Journal   (Followers: 3)
Materials Science and Metallurgy Engineering     Open Access   (Followers: 7)
Metallurgical and Materials Engineering     Open Access  
Metallurgical and Materials Transactions A     Hybrid Journal   (Followers: 41)
Metallurgical and Materials Transactions B     Hybrid Journal   (Followers: 30)
Metallurgical and Materials Transactions E     Full-text available via subscription   (Followers: 2)
Metallurgical Research & Technology     Full-text available via subscription  
Metallurgical Research and Technology     Full-text available via subscription   (Followers: 6)
Metallurgy and Foundry Engineering     Open Access   (Followers: 1)
Mining, Metallurgy & Exploration     Hybrid Journal  
Powder Diffraction     Full-text available via subscription   (Followers: 1)
Powder Metallurgy     Hybrid Journal   (Followers: 33)
Powder Metallurgy and Metal Ceramics     Hybrid Journal   (Followers: 7)
Powder Metallurgy Progress     Open Access   (Followers: 5)
Rare Metals     Hybrid Journal   (Followers: 2)
Revista de Metalurgia     Open Access  
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Revista Remetallica     Open Access  
Russian Metallurgy (Metally)     Full-text available via subscription   (Followers: 4)
Science and Technology of Welding and Joining     Hybrid Journal   (Followers: 4)
Soldering & Surface Mount Technology     Hybrid Journal   (Followers: 1)
Stainless Steel World     Full-text available via subscription   (Followers: 17)
Transactions of the IMF     Hybrid Journal   (Followers: 14)
Transactions of the Indian Institute of Metals     Hybrid Journal   (Followers: 4)
Tungsten     Hybrid Journal  
Universal Journal of Materials Science     Open Access   (Followers: 1)
Welding in the World     Hybrid Journal   (Followers: 4)
Welding International     Hybrid Journal   (Followers: 7)
Вісник Приазовського Державного Технічного Університету. Серія: Технічні науки     Open Access  
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Soldering & Surface Mount Technology
Journal Prestige (SJR): 0.399
Citation Impact (citeScore): 1
Number of Followers: 1  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0954-0911 - ISSN (Online) 1758-6836
Published by Emerald Homepage  [360 journals]
  • Investigation of ultrasound-assisted soldering of SiC ceramics by using
           Zn-Al-In solder for high-temperature applications

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      Authors: Igor Kostolný , Roman Kolenak , Paulina Babincova , Martin Kusý
      Abstract: This study aims to investigate soldering of SiC ceramics by using Zn-Al-In-based solders and ultrasonic soldering. The focus was on the quality of soldered joints, examining the boundary of the solder/substrate joint and the strength of the fabricated joints. Moreover, the fractured surfaces of joints were assessed. The Zn-5Al base, which is considered for eutectic solder, was used in experiments. When manufacturing this solder, In was also added to at 1 Wt.%. The soldering of SiC substrates on a hot plate with ultrasonic assistance was performed. The solder at room temperature consists of a primary segregated solid solution (Zn) and the binary eutectics (Zn) + (Al) with a high Al content and binary lamellar eutectic with a high Zn and In content non-uniformly distributed on the grain boundaries. The average tensile strength of the Zn5Al1In solder was 52 MPa. The ceramic material was wetted during soldering via reaction between the solder and the SiC substrate, with the formation of Al-Si reaction products. The thickness of the reaction layer on the boundary was 0.5–1.1 µm. The average strength of the soldered joint was 59 MPa. The obtained results confirmed the high efficiency of ultrasonic soldering in air. This work has characterised Zn5Al1In soldering alloy and examining soldering SiC ceramics by a flux-less ultrasonic process. The analyses were oriented to assess the strength and structure of the solder and the soldered joints. Based on the achieved results, it is possible to predict the suitability of the solder alloy for flux-free soldering of SiC ceramics.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-04-29
      DOI: 10.1108/SSMT-02-2022-0012
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Thermal and mechanical analysis of low-temperature and low-pressure
           silver-based sintered thermal joints

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      Authors: Krzysztof Jakub Stojek , Jan Felba , Damian Nowak , Karol Malecha , Szymon Kaczmarek , Patryk Tomasz Tomasz Andrzejak
      Abstract: This paper aims to perform thermal and mechanical characterization for silver-based sintered thermal joints. Layer quality affects thermal and mechanical performance, and it is important to achieve information about how materials and process parameters influence them. Thermal investigation of the thermal joints analysis method was focused on determination of thermal resistance, where temperature measurements were performed using infrared camera. They were performed in two modes: steady-state analysis and dynamic analysis. Mechanical analysis based on measurements of mechanical shear force. Additional characterizations based on X-ray image analysis (image thresholding), optical microscope of polished cross-section and scanning electron microscope image analysis were proposed. Sample surface modification affects thermal resistance. Silver metallization exhibits the lowest thermal resistance and the highest mechanical strength compared to the pure Si surface. The type of dynamic analysis affects the results of the thermal resistance. Investigation of the layer quality influence on mechanical and thermal performance provided information about different joint types.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-04-28
      DOI: 10.1108/SSMT-06-2021-0042
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Effect of TiO nanoparticles on the microstructure, mechanical and thermal
           properties of rapid quenching SAC355 lead-free solder alloy

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      Authors: Hamed Al-sorory , Mohammed S. Gumaan , Rizk Mostafa Shalaby
      Abstract: This study aims to investigate the effect of a small amount of TiO2 NPs addition on the microstructure, thermal, mechanical and electrical properties of environmentally friendly eutectic (SAC355)100-x(TiO2)x (x = 0.1, 0.3, 0.5, 0.7 and 1 wt.%) solder alloys. Mechanical, thermal and electrical properties and microstructure conditions are taken into major consideration in any study of materials containing nanoparticles. Dynamic resonance technique, X-ray diffraction and scanning electron microscopy were carried out to study stiffness, identification of the phases and the morphology features of the solder. Structure and microstructure analysis indicated that the presence of rhombohedral β–Sn phase in addition to orthorhombic intermetallic compound (IMC) Ag3Sn and Cu3Sn phase dispersed in Sn matrix. In addition, the results showed that TiO2 NPs addition at a small trace amount into SAC355 system reduces and improves the particle size of both rhombohedral β–Sn and orthorhombic IMC Ag3Sn and Cu3Sn. The interstitial dispersion of TiO2 NPs at grain boundaries resulted in Ag3Sn being more uniform needle-like, which is distributed in the β–Sn matrix. The fine and uniform microstructure leads to improvement of mechanical strength. Some important conclusions are summarized as follows: microstructure investigations revealed that the addition of TiO2 NPs particles to eutectic SAC355 inhibited in reducing and refines the crystallite size as well as the Ag3Sn IMC, which reinforced the strength of plain solder alloy. The mechanical properties values such as Young’s modulus and Vickers microhardness of SAC355 solder alloy can be significantly improved by adding a trace amount of TiO2 NPs compared with plain solder because of the existence of appropriate volume fraction of Ag3Sn IMC. The results show that the best creep resistance is obtained when the addition of 0.3 wt.% of TiO2 NPs is compared to plain solder. TiO2 NPs addition could increase the melting temperature, compared with plain solder. All results showed that TiO2 NPs addition is an effective method to enhance new solder joints. New solder alloys. Development of TiO2 NPs-doped eutectic SAC355 lead-free solder for electronic packaging.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-04-25
      DOI: 10.1108/SSMT-01-2022-0003
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Study on temperature cycling reliability of Sn-5Sb-0.5Cu-0.1Ni-0.5Ag/Cu
           micro solder joints

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      Authors: Meng Xu , Fenglian Sun , Zhen Pan , Yang Liu
      Abstract: The purpose of this paper is to study the temperature cycling reliability of Sn-5Sb-0.5Cu-0.1Ni-0.5Ag/Cu micro solder joints compared with Sn-5Sb/Cu and SAC305/Cu micro solder joints, which has important engineering and theoretical significance for the research of micro solder joint reliability. This paper also aims to provide guidance for the selection of solder for third-generation semiconductor power device packaging. The shear strength, plasticity, bulk solder hardness and creep performance of three kinds of micro solder joints before and after temperature cycling were studied by nanoindentation and micro shear experiments. Scanning electron microscopy and energy dispersive spectrometry were used to analyze the fracture mode, fracture position and compound composition of the solder joints. The bulk solder hardnesses and shear strengths of Sn-5Sb-0.5Cu-0.1Ni-0.5Ag/Cu solder joints were higher than those of Sn-5Sb/Cu and SAC305/Cu solder joints before and after temperature cycling. The indentation depth, creep displacement and creep rate of bulk solders of Sn-5Sb-0.5Cu-0.1Ni-0.5Ag/Cu solder joints were the smallest compared with those of Sn-5Sb/Cu and SAC305/Cu solder joints after the same number of cycles. In addition, the fracture mode and fracture position of the micro solder joints changed before and after temperature cycling. A new type of solder was developed with excellent temperature cycling performance.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-04-14
      DOI: 10.1108/SSMT-07-2021-0044
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Effects of alloying element on mechanical properties of Sn-Bi solder
           alloys: a review

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      Authors: Lina Syazwana Kamaruzzaman , Yingxin Goh
      Abstract: This paper aims to review recent reports on mechanical properties of Sn-Bi and Sn-Bi-X solders (where X is an additional alloying element), in terms of the tensile properties, hardness and shear strength. Then, the effects of alloying in Sn-Bi solder are compared in terms of the discussed mechanical properties. The fracture morphologies of tensile shear tested solders are also reviewed to correlate the microstructural changes with mechanical properties of Sn-Bi-X solder alloys. A brief introduction on Sn-Bi solder and reasons to enhance the mechanical properties of Sn-Bi solder. The latest reports on Sn-Bi and Sn-Bi-X solders are combined in the form of tables and figures for each section. The presented data are discussed by comparing the testing method, technical setup, specimen dimension and alloying element weight percentage, which affect the mechanical properties of Sn-Bi solder. The addition of alloying elements could enhance the tensile properties, hardness and/or shear strength of Sn-Bi solder for low-temperature solder application. Different weight percentage alloying elements affect differently on Sn-Bi solder mechanical properties. This paper provides a compilation of latest report on tensile properties, hardness, shear strength and deformation of Sn-Bi and Sn-Bi-X solders and the latest trends and in-depth understanding of the effect of alloying elements in Sn-Bi solder mechanical properties.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-04-04
      DOI: 10.1108/SSMT-06-2021-0035
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Effect of Cu, Ni, Ag addition on creeping properties of
           Sn5Sb-0.5Cu-0.1Ni-0.5Ag for high temperature packaging

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      Authors: Bangyao Han , Fenglian Sun , Chi Zhang , Xinlei Wang
      Abstract: This paper aims to investigate the effect of the Cu, Ni and Ag addition in Sn5Sb-based alloy on the mechanical properties and its mechanism. The micro-indentation, creeping test of the Cu/Sn5Sb–0.5Cu–0.1Ni–0.5Ag/Cu and Cu/Sn–5Sb/Cu were conducted, and its microstructure was analysed. The scanning electron microscope and the metallographic microscope characterized the microstructure of the Sn5Sb–0.5Cu–0.1Ni–0.5Ag/Cu and Sn–5Sb/Cu joints. The microstructure of Cu/Sn5Sb–0.5Cu–0.1Ni–0.5Ag/Cu is distributed with the fine (Cu,Ni)6Sn5 and Ag3Sn intermetallic compounds (IMCs), whereas the Cu6Sn5 and Sn3Sb2 in Cu/Sn–5Sb/Cu is larger and far more less. This investigation reveals that the addition of the Cu, Ni and Ag elements reinforced mechanical properties and provided a technical basis for the development of Sn–Sb alloy with good mechanical properties. This paper reveals that the hardness and the modulus of the bulk solder Cu/Sn–5Sb/Cu solder joints were improved with the addition of Cu, Ni and Ag trace elements. Meanwhile, the creep resistance and plasticity were also improved. This study has a great value for exploring high-performance Sn–Sb based solder alloy and has proved an example.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-03-18
      DOI: 10.1108/SSMT-09-2021-0061
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Predictive model of the solder paste stencil printing process by response
           surface methodology

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      Authors: Chun-Sheng Chen , Hai Wang , Yung-Chin Kao , Po-Jen Lu , Wei-Ren Chen
      Abstract: This paper aims to establish the predictive equations of height, area and volume of printed solder paste during solder paste stencil printing (SPSP) process in surface mount technology (SMT) to better understand the effect of process parameters on the printing quality. An experiment plan is proposed based on the response surface method (RSM). Experiments with 30 different combinations of process parameters are performed using a solder paste printer. After printing, the volume, area and height of the printed SAC105 solder paste are measured by a solder paste inspection machine. Using RSM, the predictive equations associated with the printing parameters and the printing quality of the solder paste are formed. The optimal printing parameters are 175.08 N printing pressure, 250 mm/s printing speed, 0.1 mm snap-off height and 15.7 mm/s stencil snap-off speed if the target height of solder paste is 100 µm. As the target printing area of solder paste is 1.1 mm × 1.3 mm, the optimized values of the printing parameters are 140.29 N, 100.52 mm/s, 0.63 mm and 20.25 mm/s. When both the target printing height and area are optimized together, the optimal values for the four parameters are 86.67 N, 225.76 mm/s, 0.15 mm and 1.82 mm/s. A simple RSM-based experimental method is proposed to formulate the predictive polynomial equations for height, area and volume of printed solder paste in terms of important SPSP parameters. The predictive equation model can be applied to the actual SPSP process, allowing engineers to quickly predict the best printing parameters during parameter setting to improve production efficiency and quality.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-02-25
      DOI: 10.1108/SSMT-08-2021-0056
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Development of holmium doped eutectic Sn-Ag lead-free solder for
           electronic packaging

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      Authors: Rizk Mostafa Shalaby
      Abstract: This study aims to summarize the effects of minor addition of Ho REE on the structure, mechanical strength and thermal stability of binary Sn- Ag solder alloys for high-performance applications. This study investigates the effect of a small amount of holmium addition on the microstructure, thermal stability, mechanical behaviour and wettability of environmentally friendly eutectic melt-spun process Sn – Ag solder alloys. Dynamic resonance technique, X-ray diffraction (XRD) and scanning electron microscopy were carried to study stiffness, identification of the phases and the morphology features of the solder. Structure and microstructure analysis indicated that presence of rhombohedral ß-Sn phase in addition to orthorhombic IMC Ag3Sn phase dispersed in Sn-matrix. Also, the results showed that Ho rare earth addition at a small trace amount into Sn-Ag system reduces and improves the particle size of both rhombohedral ß-Sn and orthorhombic IMC Ag3Sn based on the adsorption effect of the active RE element. The adsorption of Ho at grain boundaries resulted in Ag3Sn more uniform needle-like which is distributed in the ß-Sn matrix. The fine and uniform microstructure leads to improvement of mechanical strength. The microstructure refinement is due to the high surface free energy of IMC Ag3Sn grains, and it prevents the dislocation slipping. This maybe enhance the micro-hardness and micro-creep hence delays the breaking point of the solder. Ho (RE) trace addition could enhance the melting temperature and contact angle up to 215°C and 31°, Respectively, compared with plain solder. All results showed that Ho trace addition element has an effective method to enhance new solder joints. Effect of rare earth element Ho particles on the microstructure and mechanical behavior of eutectic Sn-3.5Ag solder alloy was studied. Some important conclusions are summarized in the following: microstructure investigations revealed that the addition of Ho particles to eutectic Sn-3.5Ag inhibited in reducing and refines the crystallite size as well as the Ag3Sn IMC which reinforced the strength of plain solder alloy. The mechanical properties values such as Young’s modulus, Vickers microhardness of Sn-3.5Ag solder alloy can be significantly improved by adding a trace amount of Ho particles compared with plain solder due to the existence of finer and higher volume fraction of Ag3SnIMC. These variations can be understood by considering the plastic deformation. The strengthening mechanism of the Sn-3.5Ag-Ho solder alloy could be explained in terms of Ho harden particles and finer IMC, which are distributed within eutectic regions because they act as pinning centres which inhibited the mobility of dislocation that concentrated around the grain boundaries. The results show that the best creep resistance is obtained when the addition of Ho 0.5 is compared to plain solder. The addition of Ho on Sn-3.5Ag lead-free solder alloy decreases the melting temperature to few degrees. Development of holmium-doped eutectic Sn-Ag lead-free solder for electronic packaging.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-02-22
      DOI: 10.1108/SSMT-10-2021-0064
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Mechanical, photoelectric and thermal reliability of SAC307 solder joints
           

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      Authors: Xinmeng Zhai , Yue Chen , Yuefeng Li , Jun Zou , Mingming Shi , Bobo Yang
      Abstract: This study aims to study the mechanical, photoelectric, and thermal reliability of SAC307 solder joints with Ni-decorated MWCNTs for flip-chip light-emitting diode (LED) package component during aging. By adding nanoparticles (Ni-multi-walled carbon nanotubes [MWCNTs]) to the solder paste, the shear strength and fatigue resistance of the brazed joint can be improved. However, the aging properties of Ni-modified MWCNTs composite solder joints have not been deeply studied. In this research, the mechanical, photoelectric and thermal reliability of SAC307 packaged flip-chip LEDs with Ni-MWCNTs added during aging were studied. Compared with SAC solder alloys, the effects of different contents (0, 0.05, 0.1 and 0.2 Wt.%) of Ni-MWCNTs on the photoelectric and thermal properties of composite solder joints were examined. To study the aging characteristics of composite solder joints, the solder joints were aged at 85°C/85% relative humidity. The addition of an appropriate amount of reinforcing agent Ni-MWCNTs reduces the density of the composite solder to 96% of the theoretical value of the SAC solder alloy. In addition, the microhardness increases and the wetting angle decreases. Two different phase compositions were observed in the solder joints with Ni-MWCNTs reinforcement: Cu3Sn and (Cu, Ni)6Sn5. The solder joints of SAC307-0.1Ni-MWCNTs exhibit the highest luminous flux and luminous efficiency of flip-chip LED filaments, the lowest steady-state voltage and junction temperature. And with the extension of the aging time, its aging stability is the best. In short, when the addition amount of Ni-MWCNTs is 0.1 Wt.%, the solder joints exhibit the best wettability and the thinnest intermetallic compound layer. And the shear strength of the tested solder joints is the best, and the void ratio is the lowest. At this time, the enhancement effect of Ni-MWCNTs on the composite solder has been best demonstrated. The content range of enhancer Ni-MWCNTs needs to be further reduced. The authors have improved the performance of Ni-modified MWCNTs composite solder joints. Composite solder with high performance has great practical application significance for improving the reliability and life of the whole device.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-02-15
      DOI: 10.1108/SSMT-08-2021-0059
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • The influence of SACX0307-ZnO nanocomposite solder alloys on the optical
           and thermal properties of power LEDs

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      Authors: Agata Skwarek , Przemysław Piotr Ptak , Krzysztof Górecki , Krzysztof Witek , Balázs Illés
      Abstract: This paper aims to present the results of investigations that show the influence of ZnO composite soldering paste on the optical and thermal parameters of power light-emitting diodes (LEDs). ZnO nanocomposite solder alloys were produced via the ball milling process from the solder paste Sn99Ag0.3Cu0.7 (SACX0307) and 1.0 wt% of ZnO nanoparticle reinforcements with different primary particle sizes (200 nm, 100 nm and 50 nm). Power LEDs were soldered onto a metal core printed circuit board. A self-designed LED test system was used to measure the thermal and optical characteristics of the LEDs. The influence of the soldering paste on the thermal and optical parameters of LEDs was observed. In all solder alloys, ZnO ceramic reinforcement, at a level of 1 wt%, increased the thermal parameters of LEDs and decreased their luminous efficiency. Thermal resistance values were10% higher, and junction temperature change over ambient temperature was 20% higher for the samples soldered with composite solder pastes than the reference sample. At the same time, luminous efficiency dropped by 32%. The results prove that ZnO ceramic reinforcement of solder paste influences the thermal properties of solder joints. As was proven, the quality of the solder joints influences the whole assembly.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-02-09
      DOI: 10.1108/SSMT-08-2021-0054
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • An intelligent system for reflow oven temperature settings based on hybrid
           physics-machine learning model

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      Authors: Yangyang Lai , Ke Pan , Yuqiao Cen , Junbo Yang , Chongyang Cai , Pengcheng Yin , Seungbae Park
      Abstract: This paper aims to provide the proper preset temperatures of the convection reflow oven when reflowing a printed circuit board (PCB) assembly with varied sizes of components simultaneously. In this study, computational fluid dynamics modeling is used to simulate the reflow soldering process. The training data provided to the machine learning (ML) model is generated from a programmed system based on the physics model. Support vector regression and an artificial neural network are used to validate the accuracy of ML models. Integrated physical and ML models synergistically can accurately predict reflow profiles of solder joints and alleviate the expense of repeated trials. Using this system, the reflow oven temperature settings to achieve the desired reflow profile can be obtained at substantially reduced computation cost. The prediction of the reflow profile subjected to varied temperature settings of the reflow oven is beneficial to process engineers when reflowing bulky components. The study of reflowing a new PCB assembly can be started at the early stage of board design with no need for a physical profiling board prototype. This study provides a smart solution to determine the optimal preset temperatures of the reflow oven, which is usually relied on experience. The hybrid physics–ML model providing accurate prediction with the significantly reduced expense is used in this application for the first time.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-02-01
      DOI: 10.1108/SSMT-10-2021-0063
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Solder void size reduction in semiconductor package by vacuum reflow and
           pressure cure processes

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      Authors: Siang Miang Yeo , Ho Kwang Yow , Keat Hoe Yeoh
      Abstract: Semiconductor packaging industry has in recent years tightened the tolerance criteria for acceptable solder void size in the semiconductor packages due to the high usage in automotive applications. Semiconductor packaging component makers have strengthened the quality of the solder joint and its electrical conductivity by controlling the maximum solder void size reduction from 10-15% to 5% or below over die size. This paper aims to reduce the solder void size to minimum level that current industry could not achieve and introduce a new soldering processes by combining vacuum reflow and pressure cure to effectively reduce solder void. This study is using the empirical data collection to prove the feasible in achieve the goal. It is an engineering approach. This research study is even considering sufficient data (>22 units) in each evaluation to represent the actual performance. Successfully eliminate all the hollow solder void that current industry claimed as solder void. EDX analysis showed that the compressed solder voids remained in the solder are filled with solid carbon-based substances which could be originated from the trapped flux residues. It is empirical data proven in feasibility stage. The study is able to produce solder void-less. This method is suitable for high volume manufacturing process also. This may lead a new pave way for industry to resolve solder void problem. The current pressure cure machine could not apply more than 200°C temperature which limits medium and high temperature solder paste or alloy testing. Therefore, only low temperature solder alloy Pb37Sn63 was able to be evaluated. This study is original and has not been published elsewhere to produce high efficiency product in semiconductor packaging performance in electrical path and heat dissipation. It also improves package reliability due to solder joint used as interconnect in semiconductor packaging.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-01-26
      DOI: 10.1108/SSMT-05-2021-0018
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Influence of the soldering paste type on optical and thermal parameters of
           LED modules

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      Authors: Krzysztof Górecki , Przemysław Ptak , Barbara Dziurdzia
      Abstract: This paper presents the results of the investigations of LED modules soldered with the use of different soldering pastes. The tested power LED modules are soldered using different solder pastes and soldering processes. Thermal parameters of the performed modules are tested using indirect electrical methods. The results of measurements obtained for different modules are compared and discussed. It was shown that the soldering process visibly influences the results of measurements of optical and thermal parameters of LED modules. For example, values of thermal resistance of these modules and the efficiency of conversion of electrical energy into light differ between each other even by 15%. The obtained results of investigations can be usable for designers of the assembly process of power LED modules. This paper shows the investigations results in the area of effective assembly of power LEDs to the metal core printed circuit board (MCPCB) using different soldering pastes (REL22, REL61, LMPA-Q6, OM-5100, OM-338-PT, M8, OM-340, CVP-390). It was shown that the best thermal and optical properties of these modules are obtained for the OM5100 paste by Alpha Assembly.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-01-14
      DOI: 10.1108/SSMT-07-2021-0043
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Study of mechanical properties of indium-based solder alloys for cryogenic
           applications

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      Authors: Madhuri Chandrashekhar Deshpande , Rajesh Chaudhari , Ramesh Narayanan , Harishwar Kale
      Abstract: This study aims to develop indium-based solders for cryogenic applications. This paper aims to investigate mechanical properties of indium-based solder formulations at room temperature (RT, 27 °C) as well as at cryogenic temperature (CT, −196 °C) and subsequently to find out their suitability for cryogenic applications. After developing these alloys, mechanical properties such as tensile and impact strength were measured as per American Society for Testing and Materials standards at RT and at CT. Charpy impact test results were used to find out ductile to brittle transition temperature (DBTT). These properties were also evaluated after thermal cycling (TC) to find out effect of thermal stress. Scanning electron microscope analysis was performed to understand fracture mechanism. Results indicate that amongst the solder alloys that have been studied in this work, In-34Bi solder alloy has the best all-round mechanical properties at RT, CT and after TC. It can be concluded from the results of this work that In-34Bi solder alloy has best all-round mechanical properties at RT, CT and after TC and therefore is the most appropriate solder alloy amongst the alloys that have been studied in this work for cryogenic applications DBTT of indium-based solder alloys has not been found out in the work done so far in this category. DBTT is necessary to decide safe working temperature range of the alloy. Also the effect of TC, which is one of the major reasons of failure, was not studied so far. These parameters are studied in this work.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-01-07
      DOI: 10.1108/SSMT-10-2021-0065
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Investigation of solder beading phenomenon under surface-mounted
           electrolytic capacitors

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      Authors: Daniel Straubinger , Attila Toth , Viktor Kerek , Zsolt Czeczei , Andras Szabo , Attila Geczy
      Abstract: The purpose of this paper is to study the solder beading phenomenon (referring to larger-sized solder balls) of surface-mounted electrolytic capacitors. Solder beading could induce failures by violating the minimal electrical clearance on the printed circuit board (PCB). In modern lead-free reflow soldering, especially in high-reliability industries, such as automotive, aeroplane and aerospace, detecting and preventing such defects is essential in reliable and cost-effective manufacturing. The large size of the involved components may block the view of automatic optical inspection; therefore, X-ray inspection is necessary. To detect the failure mode, X-ray imaging, cross-section grinding, optical microscopy and Fourier transformed infrared spectroscopy were used. High-resolution noncontact profilometry and optical microscopy were used to analyse component designs. The surface mounting process steps were also analysed to reveal their dependence on the issue. Test methods were designed and performed to reveal the behaviour of the solder paste (SP) during the reflow soldering process and to emphasise the component design relevance. It was found that the reduction of SP volume only reduces the failure rate but does not solve the problem. Results show that excessive component placement pressure could induce solder beading. Statistical analysis revealed that differences between distinct components had the highest effect on the solder beading rate. Design aspects of solder beading-prone components were identified and discussed as the primary source of the problem. The findings can be applied in surface-mount technology production, where the total failure count and resulting failure costs could be reduced according to the findings. This paper shows that component design aspects such as the low distance between the underside of the component and the PCB and blocked proper outgassing of volatile compounds of the SP can be root causes of solder beading under surface-mounted electrolytic capacitors.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2022-01-03
      DOI: 10.1108/SSMT-06-2021-0039
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2022)
       
  • Analytical and numerical analyses of filling progression and void
           formation in flip-chip underfill encapsulation process

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      Authors: Fei Chong Ng , Aizat Abas , Muhammad Naqib Nashrudin , M. Yusuf Tura Ali
      Abstract: This paper aims to study the filling progression of underfill flow and void formation during the flip-chip encapsulation process. A new parameter of filling progression that relates volume fraction filled to filling displacement was formulated analytically. Another indicative parameter of filling efficiency was also introduced to quantify the voiding fraction in filling progression. Additionally, the underfill process on different flip-chips based on the past experiments was numerically simulated. All findings were well-validated with reference to the past experimental results, in terms of quantitative filling progression and qualitative flow profiles. The volume fraction filled increases monotonically with the filling displacement and thus the filling time. As the underfill fluid advances, the size of the void decreases while the filling efficiency increases. Furthermore, the void formed during the underfilling flow stage was caused by the accelerated contact line jump at the bump entrance. The filling progression enabled manufacturers to forecast the underfill flow front, as it advances through the flip-chip. Moreover, filling progression and filling efficiency could provide quantitative insights for the determination of void formations at any filling stages. The voiding formation mechanism enables the prompt formulation of countermeasures. Both the filling progression and filling efficiency are new indicative parameters in quantifying the performance of the filling process while considering the reliability defects such as incomplete filling and voiding.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2021-12-15
      DOI: 10.1108/SSMT-08-2021-0055
      Issue No: Vol. ahead-of-print , No. ahead-of-print (2021)
       
  • Microstructural and compositional evolution of SAC305/TiN composite solder
           under thermal stressing

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      Authors: Guang Chen , Yao-Feng Wu
      Abstract: The purpose of this paper is to investigate the effect of titanium nitride (TiN) on microstructure and composition of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints under a large temperature gradient. In this paper, SAC305 lead-free composite solder containing 0.05 Wt.% TiN was prepared by powder metallurgy method. A temperature gradient generator was designed and the corresponding samples were also prepared. The microstructural evolution, internal structure and elemental content of SAC305 and SAC305/TiN solder joints before and after thermal loading were comparatively studied. The experimental results show that the addition of the TiN reinforcing phase can effectively inhibit the diffusion and migration of copper atoms and, therefore, affect the distribution of newly formed Cu-Sn IMC in solder joints under the condition of thermal migration (TM). Compared with the SAC305 solder joint, the interconnection interface and internal structure of the composite solder joint after 600 h of TM are also relatively complete. The TiN reinforcing phase is proven effective to mitigate the TM behavior in solder joints under thermal stressing. Specifically, based on the observation and analysis results of microstructure and internal structure of composite solder joint, the TiN particle can change the temperature gradient distribution of the solder joint, so as to suppress the diffusion and migration of Sn and Cu atoms. In addition, the results of Micro-CT and compositional analysis also indicate that the addition of TiN reinforcement is very helpful to maintain the structural integrity and the compositional stability of the solder joint. Different from other ceramic reinforcements, TiN has good thermo- and electro-conductivity and the thermal-electrical performance of composite solder will not be significantly affected by this reinforcement, which is also the main advantage of selecting TiN as the reinforcing phase to prepare composite solder. This study can not only provide preliminary experimental support for the preparation of high reliability lead-free composite solder but also provide a theoretical basis for the subsequent study (such as electro-thermo distribution in solder joints), which has important application significance.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2021-12-02
      DOI: 10.1108/SSMT-08-2021-0058
      Issue No: Vol. 34 , No. 3 (2021)
       
  • Impact of different aging conditions on the IMC layer growth and shear
           strength of Ni-modified MWCNTs reinforced Sn-Ag-Cu composite solder

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      Authors: Xinmeng Zhai , Yue Chen , Yuefeng Li
      Abstract: The purpose of this paper is to develop a new composite solder to improve the reliability of composite solder joints. Nano-particles modified multi-walled carbon nanotubes (Ni-MWCNTs) can indeed improve the microstructure of composite solder joints and improve the reliability of solder joints. Although many people have conducted in-depth research on the composite solder of Ni-MWCNTs. However, no one has studied the performance of Ni-MWCNTs composite solder under different aging conditions. In this article, Ni-MWCNTs was added to Sn-Ag-Cu (SAC) solder, and the physical properties of composite solder, the microstructure and mechanical properties were evaluated. In this study, the effect of different aging conditions on the intermetallic compound (IMC) layer growth and shear strength of Ni-modified MWCNTs reinforced SAC composite solder was studied. Compared with SAC307 solder alloy, the influence of Ni-MWCNTs with different contents (0, 0.1 and 0.2 Wt.%) on composite solder was examined. To study the aging characteristics of composite solder joints, the solder joints were aged at 80°C, 120°C and 150°C. The experimental results show that the content of Ni-MWCNTs affects the morphology and growth of the IMC layer at the interface. The microhardness of the solder increases and the wetting angle decreases. After aging at moderate (120°C) and high temperature (150°C), the morphology of the Cu6Sn5 IMC layer changed from scallop to lamellar and the grain size became coarser. The following two different phase compositions were observed in the solder joints with Ni-MWCNTs reinforcement: Cu3Sn and (Cu, Ni)6Sn5. The fracture surface of the solder joints all appeared ductile dents, and the size of the pits increased significantly with the increase of the aging temperature. Through growth kinetic analysis, Ni-modified MWCNTs in composite solder joints can effectively inhibit the diffusion of atoms in solder joints. In short, when the addition amount of Ni-MWCNTs is 0.1 Wt.%, the solder joints exhibit the best wettability and the highest shear strength. In this study, the effects of aging conditions on the growth and shear strength of the IMC layer of Ni modified MWCNTs reinforced SAC307 composite solder were studied. The effects of Ni MWCNTs with different contents (0, 0.1 and 0.2 Wt.%) on the composite solder were examined.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2021-11-09
      DOI: 10.1108/SSMT-09-2021-0062
      Issue No: Vol. 34 , No. 3 (2021)
       
  • Effects of Sn-Ag-x leveling layers on the microstructure and mechanical
           properties of SnBi low-temperature solder joints

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      Authors: Yang Liu , Yuxiong Xue , Min Zhou , Rongxing Cao , Xianghua Zeng , Hongxia Li , Shu Zheng , Shuang Zhang
      Abstract: The purpose of this paper is to investigate the effects of Sn-Ag-x leveling layers on the mechanical properties of SnBi solder joints. Four Sn-Ag-x (Sn-3.0Ag-0.5Cu, Sn-0.3Ag-0.7Cu, Sn-0.3Ag-0.7Cu-0.5 Bi-0.05Ni and Sn-3.0Ag-3.0 Bi-3.0In) leveling layers were coated on Cu pads to prepare SnBi/Sn-Ag-x/Cu solder joints. The microstructure, hardness, shear strength and fracture morphology of solder joints before and after aging were studied. The interfacial brittleness of the SnBi low-temperature solder joint is a key problem affecting its reliability. The purpose of this study is to improve the mechanical properties of the SnBi solder joint. Owing to the addition of the leveling layers, the grain size of the ß-Sn phase in the SnBi/Sn-Ag-x/Cu solder joint is significantly larger than that in the SnBi/Cu eutectic solder joint. Meanwhile, the hardness of the solder bulk in the SnBi/Cu solder joint shows a decrease trend because of the addition of the leveling layers. The SnBi/Cu solder joint shows obvious strength drop and interfacial brittle fracture after aging. Through the addition of the Sn-Ag-x layers, the brittle failure caused by aging is effectively suppressed. In addition, the Sn-Ag-x leveling layers improve the shear strength of the SnBi/Cu solder joint after aging. Among them, the SnBi/SACBN/Cu solder joint shows the highest shear strength. This work suppresses the interfacial brittleness of the SnBi/Cu solder joint after isothermal aging by adding Sn-Ag-x leveling layers on the Cu pads. It provides a way to improve the mechanical performances of the SnBi solder joint.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2021-11-01
      DOI: 10.1108/SSMT-08-2021-0052
      Issue No: Vol. 34 , No. 3 (2021)
       
  • A study on the effects of electrical and thermal stresses on void
           formation and migration lifetime of Sn3.0Ag0.5Cu solder joints

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      Authors: Yanruoyue Li , Guicui Fu , Bo Wan , Zhaoxi Wu , Xiaojun Yan , Weifang Zhang
      Abstract: The purpose of this study is to investigate the effect of electrical and thermal stresses on the void formation of the Sn3.0Ag0.5Cu (SAC305) lead-free ball grid array (BGA) solder joints and to propose a modified mean-time-to-failure (MTTF) equation when joints are subjected to coupling stress. The samples of the BGA package were subjected to a migration test at different currents and temperatures. Voltage variation was recorded for analysis. Scanning electron microscope and electron back-scattered diffraction were applied to achieve the micromorphological observations. Additionally, the experimental and simulation results were combined to fit the modified model parameters. Voids appeared at the corner of the cathode. The resistance of the daisy chain increased. Two stages of resistance variation were confirmed. The crystal lattice orientation rotated and became consistent and ordered. Electrical and thermal stresses had an impact on the void formation. As the current density and temperature increased, the void increased. The lifetime of the solder joint decreased as the electrical and thermal stresses increased. A modified MTTF model was proposed and its parameters were confirmed by theoretical derivation and test data fitting. This study focuses on the effects of coupling stress on the void formation of the SAC305 BGA solder joint. The microstructure and macroscopic performance were studied to identify the effects of different stresses with the use of a variety of analytical methods. The modified MTTF model was constructed for application to SAC305 BGA solder joints. It was found suitable for larger current densities and larger influences of Joule heating and for the welding ball structure with current crowding.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2021-10-27
      DOI: 10.1108/SSMT-04-2021-0012
      Issue No: Vol. 34 , No. 3 (2021)
       
  • Design criteria for pad and stencil with high pick-and-Place yield

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      Authors: Chien-Yi Huang , Christopher Greene , Chao-Chieh Chan , Ping-Sen Wang
      Abstract: This study aims to focus on the passive components of System in Package SiP modules and discusses the geometric pad designs for 01005-sized passive components, the front end design of the hole size and shape of the stencil and the parameters of the stencil sidewall coating, to determine the optimum parameter combination. This study plans and conducts experiments, where a L8(27) inner orthogonal array is built to consider the control factors, including a L4(23) outer orthogonal array to consider the noise factor, and the experimental data are analyzed by using the technique for order preference by similarity to ideal solution multi-quality analysis method. The results show that the optimum design parameter level combination is that the solder mask opening pad has no solder mask in the lower part of the component, the pad width is 1.1 times that of the component width, the pad length is 1.75 times that of the electrode tip length, the pad spacing is 5 mil, the stencil open area is 90% of the pad area, the stencil opening corner has a 3 mil chamfer angle, and the stencil sidewall is free of nano-coating. The parameter design and multi-quality analysis method, as proposed in this study, can effectively develop the layout of passive components on a high-density SiP module substrate, to stabilize the process and increase the production yield.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2021-10-14
      DOI: 10.1108/SSMT-06-2021-0037
      Issue No: Vol. 34 , No. 3 (2021)
       
  • CuSn-microporous copper composite joint for high-temperature die-attach
           applications

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      Authors: Zhen Pan , Fenglian Sun
      Abstract: The purpose of this paper is to design a novel die-attach composite joint for high-temperature die-attach applications based on transient liquid phase bonding. Moreover, the microstructure, shear strength, electrical property, thermal conductivity and aging property of the composite joint were investigated. The composite joint was made of microporous copper and Cu3Sn. Microporous copper was immersed into liquid Sn to achieve Sn-microporous copper composite structure for die attachment. By the thermo-compression bonding, the Cu3Sn-microporous copper composite joint with a thickness of 100 µm was successfully obtained after bonding at 350 °C for 5 min under a low pressure of 0.6 MPa. After thermo-compression bonding, the resulting interconnection could withstand a high temperature of at most 676 °C, with the entire Sn transforming into Cu3Sn with high remelting temperatures. A large shear strength could be achieved with the Cu3Sn-microporous copper in the interconnections. The formed bondlines demonstrated a good electrical and thermal conductivity owing to the large existing amount of copper in the interconnections. Furthermore, the interconnection also exhibited excellent reliability under high temperature aging at 300 °C. This die-attach composite joint was suitable for power devices operating under high temperatures or other harsh environments.
      Citation: Soldering & Surface Mount Technology
      PubDate: 2021-10-04
      DOI: 10.1108/SSMT-07-2021-0047
      Issue No: Vol. 34 , No. 3 (2021)
       
  • Soldering & Surface Mount Technology

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