Technical Library | 2019-04-17 21:29:14.0
Electroless nickel electroless palladium immersion gold (ENEPIG) surface finish for printed circuit board (PCB) has now become a key surface finish that is used for both tin-lead and lead-free solder assemblies. This paper presents the reliability of land grid array (LGA) component packages with 1156 pads assembled with tin-lead solder onto PCBs with an ENEPIG finish and then subjected to thermal cycling and then isothermal aging.
Technical Library | 2015-07-14 13:19:10.0
Bottom terminated components (BTC) are leadless components where terminations are protectively plated on the underside of the package. They are all slightly different and have different names, such as QFN (quad flat no lead), DFN (dual flat no lead), LGA (land grid array) and MLF (micro lead-frame. BTC assembly has increased rapidly in recent years. This type of package is attractive due to its low cost and good performance like improved signal speeds and enhanced thermal performance. However, bottom terminated components do not have any leads to absorb the stress and strain on the solder joints. It relies on the correct amount of solder deposited during the assembly process for having a good solder joint quality and reliable reliability. Voiding is typically seen on the BTC solder joint, especially on the thermal pad of the component. Voiding creates a major concern on BTC component’s solder joint reliability. There is no current industry standard on the voiding criteria for bottom terminated component. The impact of voiding on solder joint reliability and the impact of voiding on the heat transfer characteristics at BTC component are not well understood. This paper will present some data to address these concerns.
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