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1 – 10 of over 1000Z.W. Zhong, T.Y. Tee and J‐E. Luan
This paper seeks to review recent advances in wire bonding, flip chip and lead‐free solder for advanced microelectronics packaging.
Abstract
Purpose
This paper seeks to review recent advances in wire bonding, flip chip and lead‐free solder for advanced microelectronics packaging.
Design/methodology/approach
Of the 91 journal papers, 59 were published in 2005‐2007 and topics related to wire bonding, flip chip and lead‐free solder for advanced microelectronics packaging are reviewed.
Findings
Research on advanced wire bonding is continuously performed for advanced and complex applications such as stacked‐dies wire bonding, wire bonding of low‐k ultra‐fine‐pitch devices, and copper wire bonding. Owing to its many advantages, flip chip using adhesive has gained more popularity. Research on the reliability of lead‐free solder joints is being conducted world‐wide. The new challenges, solutions and new developments are discussed in this paper.
Research limitations/implications
Because of page limitation of this review paper and the large number of the journal papers available, only a brief review is conducted. Further reading is needed for more details.
Originality/value
This review paper attempts to provide introduction to recent developments and the trends in terms of the topics for advanced microelectronics packaging. With the references provided, readers may explore more deeply, focusing on a particular issue.
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Optical profilometry has many industrial uses, from machine tool measurements to microelectronics, as experts explain.
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Muna E. Raypah, Mutharasu Devarajan and Fauziah Sulaiman
Proper thermal management is a key to improve the efficiency and reliability of light-emitting diodes (LEDs). This paper aims to report the influence of applying thermally…
Abstract
Purpose
Proper thermal management is a key to improve the efficiency and reliability of light-emitting diodes (LEDs). This paper aims to report the influence of applying thermally conductive materials on thermal performance of indium gallium aluminum phosphide (InGaAlP)-based thin-film surface-mounted device (SMD) LED.
Design/methodology/approach
The LED thermal and optical parameters were determined using the combination of thermal transient tester (T3Ster) and thermal and radiometric characterization of power LEDs (TeraLED) instruments. The LED was mounted on FR4, 2W and 5W aluminum (Al) package substrates. Measurements were carried out by setting different boundary conditions: air between LED package and substrate and using thermally conductive epoxy (TIM A) and adhesive (TIM B) of thermal conductivity 1.67 and 1.78 W/mK, respectively.
Findings
For LED mounted on FR4 package, the total real thermal resistance is improved because of TIM B by 6 and 9 per cent at 50 and 100 mA, respectively. Likewise, the relative decrease in total thermal resistance of LED on 2W Al package is about 9 and 11 per cent. As well, for LED mounted on 5W Al package, the total real thermal resistance is reduced by 2 and 4 per cent.
Originality/value
No much work can be found in the literature on thermal interface material effects on thermal performance of low-power SMD LED. This work can assist in thermal management of low-power LEDs.
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Muna E. Raypah, Dheepan M.K., Mutharasu Devarajan, Shanmugan Subramani and Fauziah Sulaiman
Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications…
Abstract
Purpose
Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications. The purpose of this study is to report the influence of input current and ambient temperature on thermal resistance of InGaAlP low-power surface-mount device (SMD) LED.
Design/methodology/approach
Thermal parameters of the LED were measured using thermal transient measurement via Thermal Transient Tester (T3Ster). The experimental results were validated using computational fluid dynamics (CFD) software.
Findings
As input current increases from 50 to 90 mA at 25°C, the relative increase in LED package (ΔRthJS) and total thermal resistance (ΔRthJA) is about 10 and 4 per cent, respectively. In addition, at 50 mA and ambient temperature from 25 to 65°C, the ΔRthJS and ΔRthJA are roughly 28 and 22 per cent, respectively. A good agreement between simulation and experiment results of junction temperature.
Originality/value
Most of previous studies have focused on thermal management of high-power LEDs. There were no studies on thermal analysis of low-power SMD LED so far. This work will help in predicting the thermal performance of low-power LEDs in solid-state lighting applications.
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V. Székely, M. Rencz and B. Courtois
Thermal issues are becoming increasingly serious with the scaling down of integrated circuits and theincreasing density brought in by advanced packaging techniques…
Abstract
Thermal issues are becoming increasingly serious with the scaling down of integrated circuits and the increasing density brought in by advanced packaging techniques. Consequently, thermal issues need to be considered during both design and test. The present paper addresses thermal testing, and more specifically thermal transient testing.
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This study aims to discuss the determination of the unknown in-plane mechanical material properties of printed circuit boards (PCBs) by correlating the results from…
Abstract
Purpose
This study aims to discuss the determination of the unknown in-plane mechanical material properties of printed circuit boards (PCBs) by correlating the results from dynamic testing and finite element (FE) models using the response surface method (RSM).
Design/methodology/approach
The first 10 resonant frequencies and vibratory mode shapes are measured using modal analysis with hammer testing experiment, and hence, systematically compared with finite element analysis (FEA) results. The RSM is consequently used to minimize the cumulative error between dynamic testing and FEA results by continuously modifying the FE model, to acquire material properties of PCBs.
Findings
Great agreement is shown when comparing FEA to measurements, the optimum in-plane material properties were identified, and hence, verified.
Originality/value
This paper used FEA and RSMs along with modal measurements to obtain in-plane material properties of PCBs. The methodology presented here can be easily generalized and repeated for different board designs and configurations.
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Muna Raypah, Mutharasu Devarajan and Shahrom Mahmud
The presence of voids in the solder layer has been considered as one of the main issues causing reliability problems in optoelectronic devices. Voids can be created due to…
Abstract
Purpose
The presence of voids in the solder layer has been considered as one of the main issues causing reliability problems in optoelectronic devices. Voids can be created due to trapped gas, clean-up agent residues (fluxes), poor wettability at interface or shortcoming of the reflow process. The voids hinder the heat conduction path and subsequently, the thermal resistance will increase. The purpose of this paper is to investigate the influence of lead-free water-washable Sn96.5Ag3.0Cu0.5 (SAC305) solder paste (SP) voids on the thermal and optical performance of white high-power (HP) surface-mounted device (SMD) light-emitting diode (LED).
Design/methodology/approach
Five LEDs are mounted on five SinkPAD substrates by using the SP. The SMT stencil printing is used to control the thickness of the SP and reflow oven for the soldering process. The fraction of voids in the SP layer is calculated using the X-ray machine software. The thermal parameters of the LEDs with different voids fraction and configuration are measured using a thermal transient tester (T3Ster) system. In addition, the optical characterizations of the LEDs are determined by the thermal and radiometric characterization of power LEDs (TeraLED) and the electroluminescence by using the spectrometer.
Findings
The results showed that the thermal performance and temperature distribution are improved for the LED with lower voids fraction and good filling state of soldering. In addition, luminous flux, efficacy and color shift of the LEDs with different fraction and configurations of voids on the SP layer are compared and discussed. It is found that the color shift of LED1 of low voids fraction and higher thickness are less than other LEDs.
Originality/value
The paper provides valuable information about the effect of water-washable SAC305 SP voids fraction and filling state of solder on the thermal and optical performance of ThinGaN HP SMD LED. A comprehensive overview of the outcomes is not available in the literature. It was shown experimentally that the voids fraction, height and configuration of the SP layer could strongly influence the heat dissipation efficiency and thermal resistance. This study can help in heat diffusion investigation and failure analysis of HP SMD LEDs.
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