The role of flux activators in formulation is to remove oxides from metal surface and, hence, allow the formation metallurgical bond between substrate and solder alloy. However, activator no-clean residue on printed circuit board assemblies (PCBAs) affects climatic reliability due its hygroscopic ionic behavior under humidity exposure. Four amino acids-based wave was investigated using wetting ...

0026-2714/$ see front matter 2010 Elsevier Ltd. A doi:10.1016/j.microrel.2010.06.013 * Corresponding author. Tel.: +852 2788 7130; fax: E-mail address: [email protected] (Y.C. Chan Nano-sized, nonreacting, noncoarsening Al2O3 particles have been incorporated into eutectic Sn–Zn solder alloys to investigate the microstructure, hardness and shear strength on Au/Ni metallized Cu pads ball grid...

Title of Dissertation: EFFECT OF DYNAMIC FLEXURAL LOADING ON THE DURABILITY AND FAILURE SITE OF SOLDER INTECONNECTS IN PRINTED WIRING ASSEMBLIES Joseph Varghese, Doctor of Philosophy, 2007 Dissertation directed by: Professor Abhijit Dasgupta Department of Mechanical Engineering This dissertation investigates the durability of solder interconnects of area array packages mounted on Printed Wiring...

The underfilling BGA as an alternative to direct chip attachment for high density packaging technologies have been developed. This paper discusses the thermomechanical and metallurgical effects of underfill material and the resulting improvement in board level reliability for underfilled BGA assemblies. Finite element analysis (FEA) models were developed to predict the thermal fatigue life of t...

Leaded solder ball was replaced by leadfree solder ball which is now widely used in semiconductor industries, due to the hazardous effects of lead to human’s health and toxicity for environment. Due to this, poor solder joint strength for Ball Grid Array (BGA) packages on leadfree devices is a reliability concern when subjected to reliability stress test. With a polymer core in the solder ball ...

Due to the inherent nature of flip-chip assembly, the solder joints lie beneath the device and therefore are not amenable to visual inspection. Hence, it is important at the design stage to ensure that solder defects such as joint separation or joint shortening do not occur in the assembly. As a first step, the solder joint is modeled using a level-set approach. Unlike conventional fronttrackin...

An automated visual inspection system has been developed for use with surface mount devices (SMDs) on a printed circuit board (PCB). The system is capable of inspecting minute solder joints of fine pitch components as small as 0.3mm pitch QFP leads. A solder joint is judged using a height image and an intensity image that are detected by a unique confocal height sensor. A solder joint is classi...

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...

An accelerated thermal cycle experiment comparing similarly constructed area array devices representing Land Grid Array (LGA) and Ball Grid Array (BGA) technology with 0.254, 0.30, and 0.40mm diameter SAC305 solder balls was performed. The devices were subjected to three thermal cycle conditions in order to promote 2nd level solder fatigue. Failure data was compared using Weibull analyses. The ...

Last year’s ITC started a lecture series on unpowered opens testing. All papers last year recognized the importance of an effective method of detecting solder opens and all used some electrical method to detect solder opens, the most common manufacturing defect on today’s surface mount printed circuit boards. However non-electrical methods are available today with significant benefits such as h...