Technical Library | 2017-10-16 15:03:32.0
The miniaturization and advancement of electronic devices have been the driving force of design, research and development, and manufacturing in the electronic industry. However, there are some issues occurred associated with the miniaturization, for examples, warpage and reliability issues. In order to resolve these issues, a lot of research and development have been conducted in the industry and university with the target of moderate melting temperature solder alloys such as m.p. 280°C. These moderate temperature alloys have not resolve these issues yet due to the various limitations. YINCAE has been working on research and development of the materials with lower temperature soldering for higher temperature application. To meet this demand, YINCAE has developed solder joint encapsulant paste to enhance solder joint strength resulting in improving drop and thermal cycling performance to eliminate underfilling, edge bonding or corner bonding process in the board level assembly process. This solder joint encapsulant paste can be used in typical lead-free profile and after reflow the application temperature can be up to over 300C, therefore it also eliminates red glue for double side reflow process. In this paper, we will discuss the reliability such as strength of solder joints, drop test performance and thermal cycling performance using this solder joint encapsulant paste in detail.
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 | 2012-12-20 14:36:09.0
The increased function of personal electronic devices, such as mobile phones and personal music devices, has driven the need for smaller and smaller active and passive components. This trend toward miniaturization, occurring at the same time as the conversion to RoHS-compliant lead-free assembly, has been a considerable challenge to the electronics assembly industry. The main reason for this is the higher reflow process temperatures required for Pb-free assembly. These higher temperatures can thermally damage the PCB and the components. In addition, the higher reflow temperatures can negatively affect the solder joint quality, especially when coupled with the smaller paste deposits required for these smaller components. If additional thermal processing is required, the risk increases even more. First Published at SMTA's International Conference on Soldering and Reliability in Toronto, May 2011
Technical Library | 2014-10-23 18:10:10.0
The functional reliability of electronic circuits determines the overall reliability of the product in which the final products are used. Market forces including more functionality in smaller components, no-clean lead-free solder technologies, competitive forces and automated assembly create process challenges. Cleanliness under the bottom terminations must be maintained in harsh environments. Residues under components can attract moisture and lead to leakage currents and the potential for electrochemical migration (...) The purpose of this research study is to evaluate innovative spray and soak methods for removing low residue flux residues and thoroughly rinsing under Bottom Termination and Leadless Components
Technical Library | 2010-07-08 19:56:15.0
As technology becomes increasingly reliant on electronics, understanding the reliability of lead-free solder also becomes increasingly important. This research project focused on phase transformation kinetics with the lead-free solder SAC 305. Today in the electronics industry, SAC 305 is the most widely used solder, making it a high priority to understand its long-term stability and performance in a variety of service conditions. Recent evidence has shifted the focus from thermal aging to reflow temperature and time above liquidus values during initial solder melting.
Technical Library | 2015-06-11 21:20:29.0
The use of bottom terminated components (BTC) has become widespread, specifically the use of Quad Flat No-lead (QFN) packages. The small outline and low height of this package type, improved electrical and thermal performance relative to older packaging technology, and low cost make the QFN/BTC attractive for many applications.Over the past 15 years, the implementation of the QFN/BTC package has garnered a great amount of attention due to the assembly and inspection process challenges associated with the package. The difference in solder application parameters between the center pad and the perimeter pads complicates stencil design, and must be given special attention to balance the dissimilar requirements
Technical Library | 2012-09-27 19:50:01.0
First published in the 2012 IPC APEX EXPO technical conference proceedings. Over the past few years a new family of laminate systems has been developed to face the increasing physical demands of withstanding Pb-free soldering processes used in the assembl
Technical Library | 2007-11-15 15:54:44.0
At the contractor level once a product is required to be soldered with lead-free solders all the processes must be assessed as to insure the same quality a customer has been accustomed to with a Sn63Pb37 process is achieved. The reflow, wave soldering and hand assembly processes must all be optimized carefully to insure good joint formation as per the appropriate class of electronics with new solder alloys and often new fluxes.
Technical Library | 2022-12-05 16:28:06.0
The work evaluates the impact of latent heat (LH) absorbed or released by a solder alloy during melting or solidification, respectively, on changes of dimensions of materials surrounding of the solder alloy. Our sample comprises a small printed circuit board (PCB) with a blind via filled with lead-free alloy SAC305. Differential scanning calorimetry (DSC) was employed to obtain the amount of LH per mass and a thermomechanical analyzer was used to measure the thermally induced deformation. A plateau during melting and a peak during solidification were detected during the course of dimension change. The peak height reached 1.6 μm in the place of the heat source and 0.3 μm in the distance of 3 mm from the source. The data measured during solidification was compared to a numerical model based on the finite element method. An excellent quantitative agreement was observed which confirms that the transient expansion of PCB during cooling can be explained by the release of LH from the solder alloy during solidification. Our results have important implications for the design of PCB assemblies where the contribution of recalescence to thermal stress can lead to solder joint failure.
Technical Library | 2021-05-13 16:03:25.0
Sn-based lead-free solders such as Sn-Ag-Cu, Sn-Cu, and Sn-Bi have been used extensively for a long time in the electronic packaging field. Recently, low-temperature Sn-Bi solder alloys attract much attention from industries for flexible printed circuit board (FPCB) applications. Low melting temperatures of Sn-Bi solders avoid warpage wherein printed circuit board and electronic parts deform or deviate from the initial state due to their thermal mismatch during soldering. However, the addition of alloying elements and nanoparticles Sn-Bi solders improves the melting temperature, wettability, microstructure, and mechanical properties. Improving the brittleness of the eutecticSn-58wt%Bi solder alloy by grain refinement of the Bi-phase becomes a hot topic. In this paper, literature studies about melting temperature, microstructure, inter-metallic thickness, and mechanical properties of Sn-Bi solder alloys upon alloying and nanoparticle addition are reviewed
