Technical Library | 2009-05-07 23:23:00.0
Thermal fatigue has been one of the most serious problems for solder joint reliability. Thermo-mechanical fatigue failure is considered to be closely related to micro-structural coarsening (grain/phase growth). Factors that influence the phase growth are studied and measurement methods are discussed, including the preparation of the eutectic solder sample for phase size measurement. Three categories of models used to predict grain growth in polycrystalline materials are presented. Finally, phase growth in solder during high temperature aging and temperature cycling and its use as a damage correlation factor are discussed.
Technical Library | 2021-09-08 14:03:55.0
There is need in the industry to understand the effects of silver presence in solders from various applications perspective. This article will attempt to present a review of the key published results on the silver containing alloys along with results of our internal studies on wave soldering, surface mount and BGA/CSP applications. Advantages and disadvantages of silver at different levels will be discussed. Specifically this report will focus on the effect of silver on process conditions, drop shock resistance, solder joint survivability in high strain rate situations, thermal fatigue resistance, Cu dissolution and effects of silver in combination with other alloy additives. Specific application problems demanding high silver level and other requiring silver level to the minimum will be discussed.
Technical Library | 2023-08-04 15:27:30.0
A designed experiment evaluated the influence of several variables on appearance and strength of Pb-free solder joints. Components, with leads finished with nickel-palladium-gold (NiPdAu), were used from Texas Instruments (TI) and two other integrated circuit suppliers. Pb-free solder paste used was tin-silver-copper (SnAgCu) alloy. Variables were printed wiring board (PWB) pad size/stencil aperture (the pad finish was consistent; electrolysis Ni/immersion Au), reflow atmosphere, reflow temperature, Pd thickness in the NiPdAu finish, and thermal aging. Height of solder wetting to component lead sides was measured for both ceramic plate and PWB soldering. A third response was solder joint strength; a "lead pull" test determined the maximum force needed to pull the component lead from the PWB. This paper presents a statistical analysis of the designed experiment. Reflow atmosphere and pad size/stencil aperture have the greatest contribution to the height of lead side wetting. Reflow temperature, palladium thickness, and preconditioning had very little impact on side-wetting height. For lead pull, variance in the data was relatively small and the factors tested had little impact.
Technical Library | 2024-04-08 15:46:36.0
A designed experiment evaluated the influence of several variables on appearance and strength of Pb-free solder joints. Components, with leads finished with nickel-palladium-gold (NiPdAu), were used from Texas Instruments (TI) and two other integrated circuit suppliers. Pb-free solder paste used was tin-silver-copper (SnAgCu) alloy. Variables were printed wiring board (PWB) pad size/stencil aperture (the pad finish was consistent; electrolysis Ni/immersion Au), reflow atmosphere, reflow temperature, Pd thickness in the NiPdAu finish, and thermal aging. Height of solder wetting to component lead sides was measured for both ceramic plate and PWB soldering. A third response was solder joint strength; a "lead pull" test determined the maximum force needed to pull the component lead from the PWB. This paper presents a statistical analysis of the designed experiment. Reflow atmosphere and pad size/stencil aperture have the greatest contribution to the height of lead side wetting. Reflow temperature, palladium thickness, and preconditioning had very little impact on side-wetting height. For lead pull, variance in the data was relatively small and the factors tested had little impact.
Technical Library | 2011-12-29 17:33:21.0
2011 IPC APEX EXPO Conference Article: Surface mount area arrays (SMAA) have been in existence for decades and are increasingly becoming more important as printed circuit board (PCB) assemblies become further complex with package miniaturization and densi
Technical Library | 2012-10-04 18:52:43.0
First published in the 2012 IPC APEX EXPO technical conference proceedings... Due to the obsolescence of SnPb BGA components, electronics manufacturers that use SnPb solder paste either have to use lead-free BGAs and adjust the reflow process or re-ball t
Technical Library | 2013-06-13 15:31:24.0
Electromigration (EM) is a mass transportation mechanism driven by electron wind force, thermal gradient, chemical potential and stress gradient. According to Moore’s law, number of transistors on integrated circuits (ICs) doubles approximately every 2 years. Moore’s law holds true since its introduction in 1970s. This insatiable demand for smaller ICs size, larger integration and higher Input/Output (IO) count of microelectronics has made ball grid array (BGA) the most promising connection type in electronic packaging industry. This trend, however, renders EM reliability of solders joints a major bottleneck to hinder further development of electronics industry...
Electronic Packaging Laboratory, State University of New York
Technical Library | 2018-05-17 11:14:52.0
Intermetallic compound (IMC) growth is being studied in earnest in this past decade because of its significant effect the solder joint reliability. It appears that from numerous investigations conducted, excessive growth of IMC could lead to solder joint failure. Leading to this, many attempts has been made to determine the actual IMC thickness. However, precise and true representation of the growth in the actual 3D phenomenon from 2D cross-section investigations has remained unclear. This paper will focus on the measuring the IMC thickness using 3D surface profilometer (Alicona Focus G4). Lead free solder, Sn3.0Ag0.5Cu (SAC305) was soldered onto copper printed circuit board (Cu PCB). The samples were then subjected to thermal cycle (TC) storage process with temperature range from 0 °C to 100 °C for 200 cycles and up to 1000 cycles were completed.
Technical Library | 2014-05-12 09:24:11.0
With the advancement of the electronic industry, Package on package (POP) has become increasingly popular IC package for electronic devices, particularly in mobile devices due to its benefits of miniaturization, design flexibility and cost efficiency. However, there are some issues that have been reported such as SIR drop due to small gap between top and bottom components, difficulty underfilling and rework due to stacked IC components and process yield issues. Some suppliers have reported using some methods such as dipping epoxy paste or epoxy flux to address these issues, but so far, no customer has reported using these methods or materials in their mass production. In order to address these issues for POP assembly, YINCAE has successfully developed a first individual solder joint encapsulant adhesive.
Technical Library | 2014-06-02 11:03:45.0
With the advancement of the electronic industry, package on package (POP) has become increasingly popular IC package for electronic devices, particularly POP TMV (Through Mold Vials) in mobile devices due to its benefits of miniaturization, design flexibility and cost efficiency. However, there are some issues that have been reported such as SIR drop due to small gap between top and bottom components, difficulty underfilling and rework due to stacked IC components and process yield issues. Some suppliers have reported using some methods such as dipping epoxy paste or epoxy flux to address these issues, but so far no customer has reported using these methods or materials in their mass production. In order to address these issues for POP TMV assembly, YINCAE has successfully developed and commercialized the first individual solder joint encapsulant adhesive for mass production for years.
