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The reliability of power electronic modules is investigated in a series system configuration. The impact of the increased junction temperature, caused by initiation of degradation process, is studied and captured to assess the effect on other component degradation processes: wire bond lift-off and the chip solder joint delamination. The proposed reliability model combines physics of failure modeling...
For harsh electronics environments, where some applications (e.g., automotive and defense) require operating temperatures at 150 °C or higher, the Pb-free SnAgCu (SAC) solders such as Sn3.0Ag0.5Cu (SAC305) and Sn3.8Ag0.7Cu (SAC387) alloys are not reliable enough to replace the high-Pb, high melting temperature solders. Harsh environment electronic industries that are currently exempted from RoHS regulations...
A compliant flip chip bump design compromises of a polymer core inside a Cu pillar, a polymer encapsulated Cu pillar and the process flow to make such bumps for fine pitch flip chip package is proposed in this study. Both polymer core and polymer encapsulated Cu pillar structures are able to provide the compliance to the Cu pillar structure and reduce stress on low K dielectric layers. A structural...
This paper gives an overview on Transient Liquid-Phase Soldering (TLPS) as a new interconnect system for lighting components at package as well as chip level, where the conventional electronic production processes have been optimized for being capable of producing highly durable pore-free TLPS bonds. The growth of intermetallic phases with control of temperature, time and pressure has been investigated...
The wafer level chip scale package (WLCSP) has been widely used in mobile chipset applications since it provides a strong solution to satisfy the demands for smaller form factor, multifunctional and low cost devices. As WLCSP moves towards lower cost, higher performance and finer pitch designs to meet the increasing requirements of electronic products, there are a number of challenges in preventing...
The thermal management of modern high power LEDs is essential for their life time. An important aspect is the thermal path from the heat generated in the LED die and phosphor, over the printed circuit board (PCB) to the heat sink. The temperature of the LED die depends on the quality of the solder joint between the LED package and the copper pads on the PCB. To evaluate the quality of the solder joint...
A discussion of the most important factors affecting the reliability of alternating current photovoltaic (ACPV) modules is provided. The discussion is supported with experimental results taken from accelerated testing of multiple commercial products. Further results are provided from non-commercial experiments focused on comparisons between various encapsulation techniques. This empirical study suggests...
Solder joints are commonly used in the electronic packaging industry to provide electrical connection and serve as the mechanical support between a package and a printed circuit board (PCB). A coefficient of thermal expansion mismatch between component and board generates thermally induced strains in solder joints because of environmental temperature change, which ultimately causes fatigue failure...
In 3D-IC packages, the Si-to-Si stacking is joint by u-bump which has fine gap structure and high bump count. Because of the high density structure, the flux clean process face challenges. So, non-clean flux is another alternative. However, the flux residue can cause reliability issue such as UF delamination, corrosive relation, electro-migration due to the residue from flux. To reduce the flux residue...
A damage accumulation based interconnect fatigue failure model is developed for predicting the board-level temperature cycling (T/C) reliability of wafer level packages (WLPs). Creep and constant strain rate experiments were first performed to characterize the viscoplastic constitutive behavior of Pb-free solder. Finite element (FE) analyses based on the viscoplastic models were conducted for estimating...
As widely known the implementation of lead-free processes induced some thermo-mechanical disadvantages. Although a lot of components do have lead-free interfaces, they are not qualified for the standard lead-free reflow soldering process due to the high peak temperatures during the soldering process. Those components have to be processed by special soldering processes like selective soldering, manual...
The hermetic sealing of a Micro Electronic Mechanical (MEMS) system is a critical requirement to the functional operation of MEMS devices. Cu-Sn SolidLiquid Inter-diffusion (SLID) bonding is one such encapsulation method of achieving hermetic sealing of MEMS devices. Recently, studies have identified a cause for concern relating to the reliability of SLID bonding. These studies have shown that electroplated...
Recently Electroless Ni/Electroless Pd/Immersion Au (ENEPIG) is being offered as an alternative surface finish to established processing such as Immersion Sn, Immersion Ag, Organic solderability preservatives (OSP), Electrolytic Ni/Au (ENA), and electroless Ni/immersion Au (ENIG) surface finish. With high solder joint quality and wire bondability, it is claimed to be more cost effective as an Au layer...
In this study, the effect of pad shape on current density and temperature distributions in solder joints has been investigated by three dimensional thermo-electrical finite element analysis. The simulation results show that square, hexagonal, octagonal and rounded pads with the same thickness/volume generate different current density and temperature distributions. The maximum current densities in...
The reliability of solder joints is an important part of the quality of SMT-Boards. Accelerated reliability tests (e.g. thermal shock or others) are a possibility to test this important property. These tests are destroying tests. So it is not possible to use such tests for the characterization of the reliability of produced SMT-Boards. The IPC 610 E [1] contains a lot of quality characteristics with...
In semiconductor devices, the common Temperature Cyle on Board Failure (TCoB) are open contacts due solder joint cracks after 2000 to 4000 temperature cycles on board — as shown in figure 1 depending on individual ECU configuration and applied temperature swing. Recently, we also encounter TCoB reliability failure, but this solder joint cracks happen along lead rather than through the solder. For...
The Zn-Al solder alloy is a promising candidate to replace the conventional high lead solders (Pb-5Sn, Pb-10Sn) in automotive applications, which work in a harsh environment combined with thermal and mechanical loads. In this work, the effects of concurrent vibration and elevated temperature on the Zn-Al solder interconnection on Cu or Ni-P plated Cu substrates were studied. The test samples by forming...
Solder joint crack in thermal cycling on board (TCoB) for surface mount devices (SMD) is becoming more stringent in semiconductor market. Current TCoB literature mainly focuses on Finite Element Analysis simulation with ANSYS software to identify the most sensitive parameters affecting TCoB performance and estimating the solder fatigue life. By a given Driver Mosfet Power QFN, this paper is focusing...
Thermal cyclic test is very important for astronautic electronic products to stimulate potentially critical failures and eliminate latent defects. The design of the thermal cyclic test should take the safety of test into account to avoid over-test risks. Over-test risks can cause serious consequences, such as unnecessary life cycle consumption and products failure. A method presented in this paper...
In this study, the effect of series Pb content on shear performance of SnAgCu-xSnPb/Cu solder joint was investigated. It was found that Pb content influenced the BGA solder joint shear strength significantly. The shear strength as a function of Pb content shows a parabola trend. The shear strength increased with Pb content increased from 0% to 9.22%. Then the shear strength value kept at a high level...
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