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...

Detailed three-dimensional finite element analysis was carried out for area-array solder-bumped flip-chip packages. The analysis enabled determinations of accurate three-dimensional effects on stress distributions as well as local fracture behaviors under thermal load. The 3D analysis also estimated thermal fatigue life of solder bumps. Since dimensions of various components span more than thre...

In this paper, we described an approach in automation, the visual inspection of solder joint defects of surface mounted components on a printed circuit board, using a neural network with fuzzy rule-based classification method. Inherently, the solder joints have a curved, tiny, and specular reflective surface. This presents the difficulty in taking good images of the solder joints. Furthermore, ...

The combination of higher lead-free process temperatures, smaller print deposits, and temperature restraints on electrical components has created difficult challenges in optimizing the reflow process. Not only are the electronic components and the PWB at risk, but the ability to achieve a robust solder joint becomes difficult, especially if the PCB is thermally massive. In addition, the constan...

New Pb-free materials ask thorough verification because their properties as wetting, solderability and mechanical properties are different from these SnPb. In this paper are presented some new facts from creep and stress relaxation investigation including new arrangement for measurement. Results from creep, stress, shear and bend testing are presented for three types of solder (Sn/3.5Ag, Sn/3.8...

The increased use of area-array technology in electronic packaging recently has given greater importance to the manufacturers of predicting the thermal distribution of area-array solder interconnection. As the interconnection technology for flip chip package is getting finer and smaller and the shape of solder join becomes complex, it is extremely difficult to obtain the accurate stress and str...

Currently, the portable electronic products trend to high speed, light weight, miniaturization and multifunctionality. In that field, solder joint reliability in term of both drop impact and thermal cycling loading conditions is a great concern for portable electronic products. The transition to lead-free solder happened to coincide with a dramatic increase in portable electronic products. Sn–A...

In this paper; we described an approach to automation of visual inspection of BGA solder joint defects of surface mounted components on printed circuit board by using neural network. Inherently, the BGA solder joints are located below its own package body, and this induces a diflculty of taking good image of the solder joints by using conventional imaging system. To acquire the cross-sectional ...

As the second part to a paper presented at the 2004 SMTA Pan Pacific Symposium, this paper further summarizes the results from technical qualification of the Ni/Pd/Au process. Whereas the previous paper examined the wire bonding capabilities of this surface finish, this second paper focuses specific attention to BGA applications. In these investigations, the solder joint integrity is measured u...

Electromigration and thermomigration reliability of Sn96.5%Ag3.0%Cu0.5 (SAC305 by weight) solder joints under alternating current is studied experimentally with the maximum current density from 2.1 10 A/cm to 1.76 10 A/cm, and frequency from 100 kHz to 4 MHz. During the experiment, hot spots are observed at current crowding corners and the skin layer of solder joints. As a result, highly locali...