Technical Library | 2016-01-12 11:09:47.0
In order to meet the increasing demand of device miniaturization, high speed, more memory, more function, low cost, and more flexibility in device design and manufacturing chain, underfilling has increasingly become an essential process for the good reliability of electronic devices. Filled capillary underfill has been selected for used in package-level where there is large thermal stress caused by CTE mismatch issue, but the underfill is usually not reworkable. Unfilled capillary underfill has been used for board-level application such as BGA/CSP, POP, WL-CSP where there is need for mechanical shock resistance, the underfill is usually reworkable.
Technical Library | 2020-10-18 19:35:05.0
Interconnect reliability especially in BGA solder joints and compliant pins are subjected to design parameters which are very critical to ensure product performance at pre-defined shipping condition and user environment. Plating thickness of compliant pin and damping mechanism of electronic system design are key successful factors for this purpose. In additional transportation and material handling process of a computer server system will be affected by shock under certain conditions. Many accessories devices in the server computer system tend to become loose resulting in poor contact or solder intermittent interconnect problems due to the shock load from the transportation and material handling processes.
Technical Library | 2014-04-11 16:03:15.0
In order to meet the increasing demand of device miniaturization, high speed, more memory, more function, low cost, and more flexibility in device design and manufacturing chain, underfilling has increasingly become an essential process for the good reliability of electronic devices. Filled capillary underfill has been selected for use in package-level where there is large thermal stress caused by CTE mismatch issue, but the underfill is usually not reworkable. Unfilled capillary underfill has been used for board-level application such as BGA/CSP, POP, WL-CSP where there is need for mechanical shock resistance, the underfill is usually reworkable.
Technical Library | 2015-02-12 16:57:56.0
Electronic systems are known to be affected by the environmental and mechanical conditions, such as humidity, temperature, thermal shocks and vibration. These adverse environmental operating conditions, with time, could degrade the mechanical efficiency of the system and might lead to catastrophic failures.The aim of this study is to investigate the mechanical integrity of lead-free ball grid array (BGA) solder joints subjected to isothermal ageing at 150°C for up to 1000 hours. Upon ageing at 150°C the Sn-3.5Ag solder alloy initially age-softened for up to 200 hours. This behaviour was linked to the coarsening of grains. When aged beyond 200 hours the shear strength was found to increase up to 400 hours. This age-hardening was correlated with precipitation of hard Ag3Sn particles in Sn matrix. Further ageing resulted in gradual decrease in shear strength. This can be explained as the combined effect of precipitation coarsening and growth of intermetallic layer. The fractured surfaces of the broken solder balls were also investigated under a Scanning Electron Microscope. The shear failures were generally due to ductile fractures in bulk solders irrespective of the ageing time.
Technical Library | 2019-10-16 23:18:15.0
Despite being a continuous subject of discussion, the existence of voids and their effect on solder joint reliability has always been controversial. In this work we revisit previous works on the various types of voids, their origins and their effect on thermo-mechanical properties of solder joints. We focus on macro voids, intermetallics micro voids, and shrinkage voids, which result from solder paste and alloy characteristics. We compare results from the literature to our own experimental data, and use fatigue-crack initiation and propagation theory to support our findings. Through a series of examples, we show that size and location of macro voids are not the primary factor affecting solder joint mechanical and thermal fatigue life. Indeed, we observe that when these voids area conforms to the IPC-A-610 (D or F) or IPC-7095A standards, macro voids do not have any significant effect on thermal cycling or drop shock performance.
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