Vibration testing was conducted by Boeing Research and Technology (Seattle) for the NASA-DoD Lead-Free Electronics Solder Project. This project is a follow-on to the Joint Council on Aging Aircraft/Joint Group on Pollution Prevention (JCAAlJG-PP) Lead-Free Solder Project which was the first group to test the reliability of lead-free solder joints against the requirements of the aerospace/mi Ii ...

Three types of inexpensive Pb-free solder joints, namely Zn-based and Bi-based solders, and a CuSn alloy were studied for application to the high-temperature operation of wide band-gap power semiconductor devices using GaN or SiC. Zn– Al solder sheets, whose melting point is 380°C were prepared, and then surface oxides were removed by RF plasma etching. Subsequently, Cu thin films were deposite...

This paper reports, for the first time, the use of endoscopy for the nondestructive examination of solder joint integrity in chip scale packages (CSP) such as flip chip on flex (FCF). Borrowed from the medical instrument technology, the endoscope is used to examine visually the inside of an organ. This concept has now been developed and refined by ERSA and KURTZ, and led to an ERSASCOPE inspect...

Effects of reflow time on the interfacial microstructure and shear strength of the SAC/FeNi-Cu connections were investigated. It was found that the amount of Cu6Sn5 within the solder did not have a noticeable increase after a long time period of reflowing, indicating that the electro-deposited FeNi layer blocked the Cu atoms effectively into the solder area during a long period under liquid-con...

This paper presents the characterization of the mechanical properties of three lead-free solder alloys 95.5Sn-4.0Ag-0.5Cu (SAC405), 96.5Sn-3.0Ag-0.5Cu (SAC305), and 98.5Sn-1.0Ag-0.5Cu (SAC105) at the solder joint scale. Several actual ChipArray ball grid array (CABGA) packages were cross-sectioned, polished, and used as test vehicles. Compressive tests were performed using a nanocharacterizatio...

Keywords: Shear strength Microstructure Single-shear lap joint Intermetallic compound (IMC) Aging a b s t r a c t The effects of isothermal aging on the microstructure and shear strength of Sn37Pb/Cu solder joints were investigated. Single-lap shear solder joints of eutectic Sn37Pb solder were aged for 1–10 days at 120 °C and 170 °C, respectively, and then loaded to failure in shear with a cons...

Au over Ni on Cu is a widely used printed circuit board (PCB) surface finish, under bump metallization (UBM), and component lead metallization. It is generally accepted that less than 3 wt.% Au in Sn-Pb solder joints inhibits formation of detrimental intermetallic compounds (IMC). However, the criti­ cal limit for Au content in Pb-free solder joints is not well established. Three surface-mount ...

The joining of lead-free Sn-3.0Ag-0.5Cu (SAC305) solder alloy to metal substrate with the addition of a porous Cu interlayer was investigated. Two types of porous Cu interlayers, namely 15 ppi—pore per inch (P15) and 25 ppi (P25) were sandwiched in between SAC305/Cu substrate. The soldering process was carried out at soldering time of 60, 180, and 300 s at three temperature levels of 267, 287, ...

The development of microstructure during melting, reactive wetting and solidification of solder pastes on Cu-plated printed circuit boards has been studied by synchrotron radiography. Using Sn-3.0Ag-0.5Cu/Cu and Sn-0.7Cu/Cu as examples, we show that the interfacial Cu6Sn5 layer is present within 0.05 s of wetting, and explore the kinetics of flux void formation at the interface between the liqu...

Recently, flip-chip assembly has become mainstream for fine-pitch interconnection in large-scale integration packages. Gold studs and copper pillars with solder caps are two types of bumps in common use.[1] Gold stud bumps are commonly used for interconnecting dice with peripheral layouts. Gold-gold bonding has the advantage of a low process temperature, and gold-solder with adhesive has good w...