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As the electronic packaging density continues to increase, flip chip or stacked packaging via bump bonding is gradually replacing traditional wire bonding and will become the mainstream packaging form in the future. For copper bumps, this new type of electronic interconnection has not yet been fixed by industry standards. Therefore, this paper has made a preliminary study on the reliability of this...
This paper discussed the applications of electron energy loss spectroscopy (EELS) for element characterization in semiconductor manufacturing. The first experiment compared the ability of element chemical states analysis between EELS and X-ray photoelectron spectroscopy (XPS). Some phase change random access memory (PcRAM) product suffered TiN connection electrode failure. EELS and XPS were used separately...
In this paper, we reported a EVB Burn In (B/I) failed case of our ABCD part and led to the finding of VIA process fabrication issue with TiN film process marginal issue. This EVB B/I failed case was carried out by electrical failure analysis (EFA) and physical failure analysis (PFA) using FIB X-section and TEM. This paper also demonstrated different EFA technology, which included curve tracer analysis,...
Ultrasonic bonding based on Ni micro-nano cones array (MCA) was developed in this study. Interfacial morphologies of bonding joints were investigated. The deformation of nanocones demonstrated the complexity of initial indentation process. Analysis of morphology evolution under different bonding pressure revealed that interfacial voids shrinkage faster as pressure increase. The time dependent morphology...
The copper substrates with different preferred orientations (200) and (220) were prepared and the interfacial reactions of the Cu(200)/Sn and Cu(220)/Sn diffusion couples were studied after annealing at 423K. The thickness and morphology of the intermetallic compounds were investigated. The appearance of the Cu3Sn was observed at Cu(220)/Sn interface after aged for 4 hours and then the thickness of...
The effects of Cu orientation and stand-off-height on the microstructure and growth of IMCs in Cu/SnAgCu/Cu solder joints was investigated. Cu6Sn5 and Cu3Sn were the two key intermetallic compounds (IMCs) that formed at the interface. On (111) Cu substrate, prism-like Cu6Sn5 grains could be observed after reflowing at 250°C for 10s. On polycrystalline Cu substrate, only scallop-like Cu6Sn5 grains...
The copper substrates with different preferred orientations (200) and (220) were prepared and the interfacial reactions of the Cu(200)/Sn and Cu(220)/Sn diffusion couples were studied after annealing at 423K. The thickness and morphology of the intermetallic compounds were investigated. The appearance of the Cu3Sn was observed at Cu(220)/Sn interface after aged for 4 hours and then the thickness of...
The effects of Cu orientation and stand-off-height on the microstructure and growth of IMCs in Cu/SnAgCu/Cu solder joints was investigated. Cu6Sn5 and Cu3Sn were the two key intermetallic compounds (IMCs) that formed at the interface. On (111) Cu substrate, prism-like Cu6Sn5 grains could be observed after reflowing at 250°C for 10s. On polycrystalline Cu substrate, only scallop-like Cu6Sn5 grains...
Ultrasonic bonding based on Ni micro-nano cones array (MCA) was developed in this study. Interfacial morphologies of bonding joints were investigated. The deformation of nanocones demonstrated the complexity of initial indentation process. Analysis of morphology evolution under different bonding pressure revealed that interfacial voids shrinkage faster as pressure increase. The time dependent morphology...
Study of diffusion mechanism in low-temperature bonding method based on Cu microcones is reported. A Sn layer was electrodeposited on the Cu microcones and the electrodeposited Cu substrate then annealing at bonding temperature 463 K. IMC grains of Sn/Cu-microcones diffusion samples grew slow with smaller size. The special morphology of Cu microcones was beneficial for the growth of intermetallic...
Microstructure evolutions of as-reflowed and aged electroplated Cu/Sn/Cu sandwich structure with 20 or 40μm Sn layer have been investigated. Cu3Sn was observed at lower side of Cu/Sn/Cu structure with 40μm Sn layer after isothermal aging treatment for 24 hours, as for that structure with 20μm Sn layer, Cu3Sn appeared after aging for 48 hours. Regardless of Sn volume, the thickness of the blanket Cu...
The formation and growth of intermetallic compounds of Sn-2.0Ag-2.5Zn solder on Cu and Ni substrates after soldering and subsequent aging process have been investigated in this study. Ni films were electrodeposited on copper substrates. The interfacial micrographs of solder joints prepared at 250°C for 15s and aged for 24h, 96h and 216 h respectively. Double-layer IMC composed with Cu5Zn8 and Ag3Sn...
In this paper, the Sn-3.5Ag solder bumps were prepared successfully by two-step electroplating method. The effect of reflow time on shear property of solder bumps and Cu was investigated. After shear tests, the shear strength of Sn-3.5Ag solder bumps peaked at the reflow time of 60s, and then decreased with further increasing reflow time. It was considered that the variation of shear strength was...
In this paper, the effect of Ni-W alloy barrier layer on copper pillar/Sn IMCs evolution has been investigated. Additive W weight content of Ni-W alloy ranged from 16 to 18 at. %. Controlled thickness of barrier layer was prepared on Cu substrate. Then, excessive matte Sn electroplated on as-deposited Ni-W layer. Ni-W had compact microstructure in state of FCC solid solution, which means it had good...
In response to lead-free requirements and market forces, pure tin finishes have been widely used as a Pb-free option for semiconductor lead frames and electrical connectors in the microelectronics industry. Pure tin finishes could easy have a discoloration during reflow process since the reflow temperature is as high as 260°C, which could lead to a reliability issue. In this work, matte tin was electroplated...
Electronic assembly technology is in the transition from traditional tin-lead to lead-free. In comparison with Sn-Pb solders, high melting point and poor wettability of the lead-free solders lead to great challenge to present electronic assembly technologies. Inert nitrogen atmosphere can both widen the process window of reflow and improve the mechanical reliability of solder joints. The focus of...
Electroless Sn films have great potential in the lead-free age such as for high-density, fine-pitch, narrow soldering pad and bump interconnection applications. In the present work, electroless Sn were deposited onto lead-frame alloys (C194 and FeNi42). The microstructures of the electroless Sn films and tin whisker growth in thermal / humiditive chamber were investigated with scanning electron microscope...
The oxidation behavior of Sn-9Zn-3Bi-xCr(x=0, 0.1, 0.3, 0.5) solders under 250°C has been investigated as a function of exposure time. The evolution of surface and cross-sectional microstructure has been examined through back-scattered electron detector (BSE). Energy-dispersive x-ray spectroscopy (EDX) and x-ray diffractometer analysis (XRD) were also carried out to check the overall composition of...
Low cost electrodeposited Sn3.5Ag solder bumps fabrication technology was developed for three-dimensional packaging applications. Effect of reflow time on interfacial reaction of electroplated Sn3.5Ag solder bumps with Cu under-bump metallization (UBM) was investigated. The microstructure of eutectic Sn3.5Ag is composed of β-Sn phase and Ag3Sn IMCs in the solder region. At the interface between solder...
With rapid growing popularity, microblogs have become a great source of consumer opinions. Confronting unique properties and massive volume of posts on microblogs, this paper proposes a summarization framework that provides compact numeric summarization for microblogs opinions. The proposed framework is designed to cope with four major tasks: 1) topics detection, 2) sentiment classification, 3) credibility...
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