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Novel Mid-Temperature Alloy for Enabling Solder Processing Temperature Hierarchy in SMT assembly

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Novel Mid-Temperature Alloy for Enabling Solder Processing T...

2019中国高端SMT学术会议

作者： Sathish Kumar Nicholas Herrick Ranjit Pandher Morgana Ribas Amit Patel Gyan Dutt Ravi Bhatkal alpha assembly solutions a MacDermid Performance Solutions Business

Establishing a solder processing temperature hierarchy with traditional tin/silver/copper（SAC） as the level 1 alloy has been a major challenge in SMT *** lower temperature options have been plagued with low operating temperature window（too low melting temperature） and poor mechanical strength of the *** this study we present process and reliability data for a new off-eutectic alloy with melting point range（192-203℃）.This alloy has the potential to fill a key gap in the alloy choices for Level2 applications for LED,computer,server,and telecommunications *** solder alloy,being significantly different from the conventional lead-free solders,necessitates a completely different flux *** material properties and the solder paste processing through SMT assembly is discussed in *** alloy reliability（drop-shock and thermal cycling） was benchmarked against traditional Pb-free solders currently in the *** from traditional SMT assembly,alloy functional performance in LED applications was also *** results of thermo-mechanical reliability tests of the solder as well as the impact of flux chemistry on the LED performance over time are presented.

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High Performance Electronic Interconnect Materials Characterization–Techniques ＆ Challenges

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High Performance Electronic Interconnect Materials Character...

2018中国高端SMT学术会议

作者： Nicholas Herrick Amit Patel Gyan Dutt Ranjit Pandher alpha assembly solutions

High-power and LED devices generate significant heat that,if not efficiently removed from the assembly,leads to lower operating efficiency and/or lower luminous flux and shorter *** the majority of heat is transported through the device interconnect layer,the thermal resistance of the heat path significantly impacts overall device *** thermal conductivity interconnect materials significantly decrease the thermal resistance of the *** effects of high performance interconnect materials are easy to observe and affect end user performance and reliability（*** increasing total luminous flux,efficiency,and color stability）.These effects become more pronounced as these devices are over driven and are particularly important in power electronics and UV LED *** this study,a series of interconnect materials,including sintered nano-silver,SAC305 and a hybrid silver sintering epoxy,were used to assemble high-power AlGaInP/Si LEDs for laboratory *** temperature,thermal resistance,thermal conductivity,total luminous flux,peak wavelength,and efficiency were measured according to JESD51-1 and *** this paper we discuss the technical and design challenges associated with making accurate thermal resistance measurements across a multi-layered *** results of this laboratory study show the comparative performance of identical devices assembled with a variety of interconnect materials.A field example showing enhanced UV LED device performance with high thermal interconnect material is presented.

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Characterization and Optimization of Board Warpage for Linear LED Lighting Assemblies

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Characterization and Optimization of Board Warpage for Linea...

2018中国高端SMT学术会议

作者： Amit Patel Karen Tellefsen Sarjil Mansuri Ranjit Pandher alpha assembly solutions

＜正＞Board warpage in fiber-glass epoxy laminate boards known as"FR"boards,is familiar phenomenon seen in traditional electronics *** growth of the LED general lighting market has propelled the usage of high-aspect ratio boards where the length is significantly greater than the width FR type boards for a variety of applications.A significant

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Effect of Voids on Thermo-Mechanical Reliability of Solder Joints

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Effect of Voids on Thermo-Mechanical Reliability of Solder J...

2019中国高端SMT学术会议

作者： Morgana Ribas Siuli Sarkar Carl Bilgrien Tom Hunsinger MacDermid alpha assembly solutions Performance solutions alpha India R&D Centre

＜正＞Despite being a continuous subject of discussion,the existence of voids and their effect on solder joint reliability has always been *** this work we revisit previous works on the various types of voids,their origins and their effect on thermo-mechanical properties of solder *** focus on macro voids,intermetallics micro voids,and shrinkage voids,which result from solder paste and alloy *** compare results from the literature to our own

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Self-assembly of Chiral Nano-bowl from Chiral Pd-complex Building Corners and 4,7-Phenanthroline Linkers

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Chinese Journal of Chemistry 2015年第1期33卷 152-155页

作者： Lina Yu Xuanfeng Jiang Shuyan Yu Laboratory for Self-assembly Chemistry Department of ChemistryRenmin University of ChinaBeijing 100872China

A chiral[M_(3)L_(3)]^(6+)-type nanobowl reported here was self-assembled from cis-protected mono-palladium com-plex[(RRdiph)Pd](NO_(3))_(2)(where RRdiph=(1R,2R)-(+)-1,2-diphenylethylenediamine)as chiral corners and 4,7-phenanthroline ligand(L)as linkers in aqueous *** hydrophobic cavity-containing metallo-macrocycle[Pd_(3)L_(3)]^(6+)·6NO_(3)(1)with a syn,syn,syn orientation has been characterized by 1H NMR spectroscopy,elemental analysis,CD spectra and X-ray diffraction determination.

关键词： self-assembly macrocycles chirality palladium

Impact of Substrate Materials On Reliability of High Power LED Assemblies

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Impact of Substrate Materials On Reliability of High Power L...

第十一届中国高端SMT学术会议

作者： Ranjit Pandher Ravi Bhatkal alpha assembly solutions a MacDermid Performance Solutions Business Kurt-Jürgen Lang Osram Opto Semiconductors

＜正＞New high power LED package designs provide high lumen density that can enable significant system cost reductions through fewer LEDs and smaller *** materials stack determines the CTE mismatch between the high power LED ceramic sub-mount and the substrates（including Metal Core PCB or FR4 substrate types）.Choice of the

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To Secure a Safe and Effective Flight—An Interview with *** Chen,PI of WXT mirror assembly

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Bulletin of the Chinese Academy of Sciences 2022年第1期36卷 16-20页

作者： ZHANG Chen SONG Jianlan WXT mirror assembly 不详

Editor’s note:Covering an unprecedentedly wide field of view(FoV)up to 3,600 square degrees,the Widefield X-ray Telescope(WXT)to fly aboard the Einstein Probe satellite will perform all-sky surveys for high-energy *** will make this possible is its special optical system powered by a technology called the Lobster-eye micro-pore optics(MPO).The development of this very important system is in the charge of *** Chen,Principal Investigator of the WXT mirror *** works as a representative for the science team in the engineering work to make sure the instrument is meeting the preset scientific *** challenging is it to build this payload?How the development is going?Let’s hear what *** would like to say on instrument calibration in a talk with BCAS staff reporter SONG Jianlan.

关键词： mirror instrument payload

A Novel Palladium(Ⅱ)Complex Self-assembled from Anthracene-9-carboxylic Acid:Synthesis,Crystal Structure and Spectroscopic Properties

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Chinese Journal of Structural Chemistry 2013年第10期32卷 1530-1536页

作者：代爽蒋选丰童金于澍燕 Laboratory for Chemical Self-assembly Chemistry Department of ChemistryRenmin University of China

A novel palladium（II） complex [（TMEDA）Pd（anca）2].2DMSO （1, TMEDA = N,N,N＇,N＇-tetramethylethylethylenediamine, anca = anthracene-9-carboxylic acid） was synthesized and characterized by single-crystal X-ray diffraction, 1H NMR, UV-Vis and fluorescence spectroscopy. The cell belongs to orthorhombic Aba2 space group with a = 19.698（7）, b = 21.045（7） c = 9.062（3） A, Z = 4, V= 3757（2） A3, C40H46N206PdS2, Mr = 821.31, D, = 1.452 g/cm3, F（000） = 1704, the final R = 0.0272, wR = 0.0667 and GOOF = 0.999. Complex 1 exhibits an interesting distorted clip-shaped molecular configuration which is stabilized by intramolecular C-H...O hydrogen bonds. The cells are packed into a 3D supramolecular structure based on the intermolecular C-H...zr interactions which further construct the tubular channels serving as guest molecular channels to include the DMSO solvent molecules inside. Furthermore, the spectroscopic properties of 1 were also investigated.

关键词： palladium(II) complex anthracene-9-carboxylic acid self-assembly crystal structure spectroscopic property

High mobility organic semiconductors for field-effect transistors

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Science China Chemistry 2015年第6期58卷 947-968页

作者： Xike Gao Zheng Zhao Key Laboratory of Synthetic and Self-assembly Chemistry for Organic Functional Molecules Shanghai Institute of Organic Chemistry Chinese Academy of Sciences

Organic field-effect transistors(OFETs) are attracting more and more attention due to their potential applications in low-cost, large-area and flexible electronic products. Organic semiconductors(OSCs) are the key components of OFETs and basically determine the device performance. The past five years have witnessed great progress of OSCs. OSCs used for OFETs have made rapid progress, with field-effect mobility much larger than that of amorphous silicon(0.5?1.0 cm2/(V s)) and of up to 10 cm2/(V s) or even higher. In this review, we demonstrate the latest progress of OSCs for OFETs, where more than 50 representative OSCs are highlighted and analyzed to give some valuable insights for this important but challenging field.

关键词： organic semiconductor organic field-effect transistor high mobility organic electronics design and synthesis