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The reliability of 0.5 mm pitch, 32‐pin thin small outline package (TSOP) solder joints has been studied by experimental temperature cycling and a cost‐effective 3‐D non‐linear finite element analysis. Temperature cycling results have been presented as a Weibull distribution, and an acceleration factor has been established for predicting the failure rate at operating conditions. Thermal fatigue life of the corner solder joints has been estimated based on the calculated plastic strain, Coffin‐Manson law and isothermal fatigue data on solders. A correlation between the experimental and analytical results has also been made. Furthermore, failure analysis of the solder joints has been performed using scanning electron microscopy (SEM) and an optical method. Finally, a quantitative comparison between the Type‐I and Type‐II TSOP solder joints has been presented.

Alloy 42 and, similarly, Kovar were developed to provide metallic feed‐throughs from the interior of ceramic components to the exterior. The low coefficient of thermal expansion (CTE) of ceramic needs to be almost matched by the feed‐through metal to allow reliable hermetically sealed connections. For this purpose these alloys have served very well. However, because of its wide‐spread use for military applications, for which component hermeticity has been required, as well as because of the easier attachment of low‐CTE die to low‐CTE lead frames, Alloy 42 has found its way into plastic components with often disastrous results. When surface mount solder joints connect materials with different CTEs, global thermal expansion mismatches result. Also, if the materials to which the solder bonds have CTEs that differ from the CTE of solder, local thermal expansion mismatches result. These thermal expansion mismatches are the cause of most SM solder joint failures. Alloy 42 and Kovar not only cause significant global and local thermal expansion mismatches, but are inherently more difficult to solder because of the low solubility of nickel and iron, the main constituents of these alloys, in tin. Pull tests of solder joints show that under the best of circumstances a solder joint that includes an Alloy 42 or Kovar surface is only half as strong as one made to copper surfaces.

The reliability of 0.4 mm pitch, 28 mm body size, 256‐pin plastic quad flat pack (QFP) no‐clean and water‐clean solder joints has been studied by temperature cycling and analytical analysis. The temperature cycling test was run non‐stop for more than 6 months, and the results have been presented as a Weibull distribution. A unique temperature cycling profile has been developed based on the calculated lead stiffness, elastic and creep strains in the solder joint, and solder data. Also, the thermal fatigue life of the solder joints has been estimated and correlated with experimental results. Furthermore, a failure analysis of the solder joints has been performed using scanning electron microscopy (SEM). Finally, a quantitative comparison between the no‐clean and water‐clean QFP solder joints has been presented.

A viscoplastic constitutive model, the Anand model, in which plasticity and creep are unified and described by the same set of flow and evolutionary relations, was applied to represent the inelastic deformation behavior for solder alloys. After conducting creep tests and constant strain rate tests, the material parameters for the Anand model of the Pb‐rich content solder 92.5Pb5Sn2.5Ag were determined from the experimental data using a nonlinear fitting method. The material parameters for 60Sn40Pb, 62Sn36Pb2Ag and 96.5Sn3.5Ag solders were fitted from the conventional model in the literature where plasticity and creep are artificially separated. Model simulations and verifications reveal that there is good agreement between the model predictions and experimental data. Some discussion on this unified model is also presented. This viscoplastic constitutive model for solder alloys possesses some advantages over the separated model. The achieved Anand model has been applied in finite element simulation of stress/strain responses in solder joints for chip component, thin quad flat pack and flip‐chip assembly. The simulation results are in good agreement with the results in the literature. It is concluded that the Anand model could be recommended as a useful material model for solder alloys and can be used in the finite element simulation of solder joint reliability in electronic packaging and surface mount technology.

The purpose of this paper is to develop a cost effective ball grid array (BGA) workcell for solder ball attachment.

This paper presents the construction of a low‐cost high‐efficiency automatic ball attachment workcell. In fact, it is an economical means of simultaneous placement of all solder balls on BGA substrates containing multiple BGA units as well as singulated substrates. Common industry problems such as the effect of static charges, the solder ball oxidation, the missing ball, the extra ball, the ball alignment, the deformed ball and, etc. will be addressed and critical issues affecting yield will also be discussed in this paper.

BGA is a popular integrated circuit packaging that is often applied in laptop computers and other handheld electronic devices for the provision of a high‐connection count in a relatively small area. However, the cost of a market available BGA solder ball attachment workcell is very expensive and the flexibility in fitting various customized process is usually low.

The developed workcell cost is about half of the market available machines with similar specifications; the yield achieved is within three sigma confidence interval with competitive output rate. The maintenance and troubleshooting are easy since the machine was developed by the in‐house engineering team.