The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Electroplated Ni/Au over Cu is a popular metallization for printed circuit board (PCB) finish as well as for component leads, especially for wire-bondable high frequency packages, where the gold thickness requirement is high (≥ 20 µinches) for wire bonding. This study examines the effect of redeposition of bulk AuSn4 IMC as a function of varying gold content (2–5 nominal weight-%) in the solder joint...
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...
Wide bandgap materials have become very attractive for power electronics due to their physical properties that allow junction temperatures up to a theoretical limit of 600°C. In contrast, the maximum operation temperature of conventional silicon semiconductors is limited to approximately 200°C. The high-temperature operation of wide bandgap switches allows an increasing power density of power converters...
For satisfying the current industrial need of downscaling electronic devices, the die-to-die or die-to-package interconnects need to decrease in size accordingly. In view of that, flip chip bumps, which are currently the smallest interconnect type, have to be further miniaturized. In this study, Cu-Sn-Cu TLP (Transient Liquid Phase) bonded bumps that consist entirely of intermetallics (IMC) are studied...
The influence of the standoff height, pad size and isothermal aging on the microstructure and shear fracture behavior of Cu/Sn-3.0Ag-0.5Cu/Cu BGA structured interconnects were investigated using the lap-shear test. The experimental results show that the thickness of intermetallic compounds (IMC) layer at the solder/Cu interface increases with decreasing standoff height of the joints. The size of Kirkendall...
The microstructual stability of Sn-8Zn-3Bi/Cu and Sn-8Zn-3Bi-0.3Cr/Cu joints has been investigated under 85 °C temperature and 85% humidity conditions as a function of exposure time. The evolution of interface and near surface cross-sectional microstructures during exposure has been examined. A continuous single layer of intermetallic compound (IMC, hereafter) appears in both of the two kinds of solders...
The current study revealed that the growth kinetics and the interfacial reaction of the Cu/Sn/Ag couples with different thickness solder. For the Cu/Sn/Ag couples, plate-type Ag3Sn was firstly formed at the Sn/Cu interface rather than at the Sn/Ag interface for the Cu/Sn/Ag couple at the initial state of the reflow procedure when the solder thicknesses is 150 μm or 300 μm. Besides, the microstructure...
In the present study, the interaction between thin film Cu and non-eutectic Sn-In is studied. The effects of the bonding and aging temperature on microstructure, IMC formation and also shear strength are investigated by SEM/EDX, XRD and shear testing. The bonding mechanism is proposed based on the obtained results. The bonding mechanism is proposed to occur over 2 stages: (1) An increase in bonding...
This paper deals with presentation of some new aspects of solder ternary alloy 96.5Sn3Ag0.5Cu (wt.%) - SAC305, in order to determine variations in mechanical properties and microstructure caused by treatment in vapour phase soldering (VPS) as well as by accelerated isothermal aging. These specimens have been melted and solidified on HASL (hot air solder levelling) and Ni/Au (ENIG) PCB (printed circuit...
The objective of this study is to investigate the alloying effects of Fe, Co, and Ni on the interfacial reactions between solder and Cu. Emphasis is placed on a systematic comparison study on the effect of Fe, Co, and Ni additions. Solders with simultaneous Fe and Ni addition as well as simultaneous Co and Ni addition are also prepared in order to investigate whether there is any interaction between...
The goal of this research is to evaluate the effects of La addition on the microstructure and microhardness of Sn-Ag based solders. Sn-3.5Ag-xLa ternary alloy solders were prepared by adding 0-1.0 wt% La into a Sn-3.5Ag alloy. Copper substrates were then dipped into these solders and aged at 150degC for up to 625 hours. The microstructure and microhardness of the as solidified solder and the aged...
Electroplated copper is becoming increasingly important in UBM (under bump metallurgy). The Cu is used as a wetting material for the solder (ball). After reflow the Cu and solder joints are the main contact method for mechanical and electrical interconnection to the pads of the chip. One of the critical factors affecting solder joint reliability is the formation of intermetallic compound (IMC); that...
Zn was added into Sn-Bi solder to investigate the effect of Zn on the microstructure of the alloy. Zn addition was found to refine and redistribute the Bi-rich phase. With Zn addition, a different intermetallic compound, Cu5Zn8 was formed at the Sn-Bi-Zn/Cu interface upon reflow. After aging, the Bi segregation was not observed at the Sn-Bi-Zn/Cu interface while a continuous Bi segregation layer appeared...
Due to the miniaturization trend and functional demand in high-density microelectronic packaging, the thermomigration in flip chip solder joints owing to the joule heating becomes a serious reliability issue. In this study, a novel apparatus which can provide a sufficient temperature gradient cross the solder joint in the specimen was used to carry on the thermomigration experiment separated from...
The atom diffusion and growth behavior of intermetallic compound (IMC) at Sn3.5Ag0.5Cu/Cu interfaces under isothermal aging and thermal-shearing cycling conditions were investigated. The results show that the morphology of Cu6Sn5 IMCs formed at Sn3.5Ag0.5Cu/Cu interface changed gradually from scallop-like to chunk-like, and IMCs thickness developed with the isothermal aging and thermal-shearing cycling...
The chip to chip bonding technique using a Cu bump capped with thin Sn layers has been frequently applied to 3D chip stacking technology. We studied the effect of the microstructure on the joints. The joints were fabricated by joining micro-Cu bumps capped with Sn-Ag solder with sizes of 10 mum times 10 mum, 20 mumtimes 20 mum, and 30 mum times 30 mum to Cu pads capped with Sn-Ag solder at 245degC-330...
Sn-Ag-Cu (SAC) solders are susceptible to appreciable microstructural coarsening during storage or service, resulting in evolution of joint properties, and hence reliability, over time. Although the problem of microstructural coarsening in joints has been studied extensively, the effect of joint scale on aging kinetics has never been investigated. Understanding the scale dependence of aging is particularly...
In this paper, the effect of SiC nano-particles in micro-solder bump was investigated. SiC nano-particles were dispersed by using ultrasonic homogenizer in plating solution of eutectic Sn58Bi solder and codeposited in eutectic Sn58Bi solder bumps. Solder bumps were fabricated on patterned wafer. Prepared samples were aged for 100, 256 and 400 hrs at 100??C respectively, and then the observation of...
The intermetallic growth in the Sn-Ag-Cu (SAC) solder joints fabricated on Cu or Cu-Zn solder wetting layer and its effect on the drop impact reliability have been studied. The drop test specimens were fabricated by connecting two printed circuit boards by reflowing SASC 405 solder balls on Cu or Cu-Zn wetting layers. And the drop test specimens were aged at 150degC up to 500 hrs. The well known bi-layer...
The present study investigates the effect of 1~5 wt.% Indium additions on microstructure, properties and interfacial IMC's formation of Sn-3Ag-2Sb(SAS) lead-free solder alloys. Experimental results show that addition of indium results in formation of intermetallic compounds of Ag-Sn-In phase and InSb phase. Sn atoms in Ag3Sn compound formed originally in Sn-Ag solder system are replaced by In atoms...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.