共查询到20条相似文献,搜索用时 125 毫秒
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LED电极结构极大地影响着LED芯片的电流扩展能力,优化电极结构,能够缓解电流拥挤现象.讨论了正装LED结构和倒装LED结构的电流分布模型,并通过SimuLED软件研究了电极结构对LED电流扩展能力的影响.仿真结果表明:采用插指型电板结构极大提高了正装LED的电流扩展能力,电极下方插入电流阻挡层(CBL)后改变了芯片的电流分布状况,有利于光效的提升;而倒装LED的通孔式双层金属电极结构利用两层金属的互联作用,使n电极能够在整个芯片范围内均匀分布,进一步提高了电流扩展性能. 相似文献
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功率型LED封装技术 总被引:3,自引:1,他引:2
随着LED芯片输入功率的提高,带来了大的发热量及要求高的出光效率,给LED的封装技术提出了更新更高的要求,使得功率型LED的封装技术成为近年来的研究热点.首先介绍了几种主要的功率型LED封装结构,对功率型LED封装过程的关键技术,如荧光粉涂覆技术、散热技术、取光技术、静电防护技术等及未来发展方向进行了描述.指出功率型LED封装应选用新的封装材料,采用新的工艺和新的封装理念来提高LED的性能和光效,延长使用寿命,以推进LED固体光源的应用. 相似文献
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《Electron Devices, IEEE Transactions on》2008,55(12):3375-3382
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高压(HX)倒装LED是一种新型的光源器件,在小尺寸、高功率密度发光光源领域有广泛的应用前景.设计了4种不同工作电压的高压倒装LED芯片,进行了流片验证,并对其进行了免封装芯片(PFC)结构的封装实验,在其基础上研制出一种基于高压倒装芯片的PFC-LED照明组件.建立了9V高压倒装LED芯片、PFC封装器件及照明组件的模型,利用流体力学分析软件进行了热学模拟和优化设计;利用T3Ster热阻测试分析仪进行了热阻测试,验证了设计的可行性.结果表明,基于9V高压倒装LED芯片的PFC封装器件的热阻约为0.342 K/W,远小于普通正装LED器件的热阻.实验结果为基于高压倒装LED芯片的封装及应用提供了热学设计依据. 相似文献
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Chien-Ping Wang Tzung-Te Chen Han-Kuei Fu Tien-Li Chang Pei-Ting Chou Mu-Tao Chu 《Microelectronics Reliability》2012,52(4):698-703
The purpose of this study is to investigate the thermal behavior at the die-attached interfaces of flip-chip GaN high-power light emitting diodes (LEDs) using a combination of theoretical and experimental analyses. The results indicate that contact thermal resistance increased dramatically at the die-attached interfaces with aging time and stress, degrading the luminous flux. The junction temperature and thermal uniformity of the flip-chip structure both strongly depend on the arrangement of gold bumps. Local hot spots effectively reduce light output under high electric and thermal stress, influencing the long-term performance of the LED device. The results were validated using finite element analysis and in experiments using an infrared and an emission microscope. A two-step thermal transient degradation mode was identified under various aging stresses. A simulation further optimized the bump configuration that was associated to yield a low junction temperature and high temperature uniformity of the LED chip. Accordingly, the results are helpful in enhancing the performance and reliability of high-power LEDs. 相似文献
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Tong Hong Wang 《Microelectronic Engineering》2010,87(12):2463-2467
Thermal analysis was performed in this work to compare the thermal performance of a board-level high performance flip-chip ball grid array package equipped with solid Cu or vapor chamber (VC) as the heat spreader and Al-filler gel or In solder as the thermal interface material (TIM). The effect of different heat source sizes was also examined. Numerical results indicate that for the particular test vehicle under a power dissipation of 160 W, the thermal performance is remarkably enhanced by switching TIM from Al-filler gel to In solder while the enhancement by using VC instead of solid Cu heat spreader is only observable when In solder is incorporated. Moreover, the performance of VC gradually enhances then retards as the heat source size decreases. The retardation can be attributed to the more dominant role of die in heat dissipation when the heat source size gradually shrinks. 相似文献
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Electronic speckle pattern interferometry (ESPI) was applied to noncontact, real-time evaluation of thermal deformation in
a flip-chip solder joint. To measure the deformation of such tiny components as the solder balls in the flip-chip, the spatial
resolution of ESPI was increased to submicron scale by magnifying the areas studied. Experimental-computational procedures
were developed to obtain stress-strain curves for solder balls in the flip-chip based on finite-element modeling (FEM) of
in-plane ESPI thermal displacement data. The stress-strain curve obtained for the flip-chip solder was compared with those
for bulk solder. The microstructure was also studied to clarify the stress-strain curve results. 相似文献
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Y. J. Hu Y. C. Hsu T. S. Huang C. T. Lu Albert T. Wu C. Y. Liu 《Journal of Electronic Materials》2014,43(1):170-175
Various microstructural zones were observed in the solidified solder of flip-chip solder joints with three metal bond-pad configurations (Cu/Sn/Cu, Ni/Sn/Cu, and Cu/Sn/Ni). The developed microstructures of the solidified flip-chip solder joints were strongly related to the associated metal bond pad. A hypoeutectic microstructure always developed near the Ni bond pad, and a eutectic or hypereutectic microstructure formed near the Cu pad. The effect of the metal bond pads on the solder microstructure alters the Cu solubility in the molten solder. The Cu content (solubility) in the molten Sn(Cu) solder eventually leads to the development of particular microstructures. In addition to the effect of the associated metal bond pads, the developed microstructure of the flip-chip solder joint depends on the configuration of the metal bond pads. A hypereutectic microstructure formed near the bottom Cu pad, and a eutectic microstructure formed near the top Cu pad. Directional cooling in the flip-chip solder joint during the solidification process causes the effects of the metal bond-pad configuration. Directional cooling causes the Cu content to vary in the liquid Sn(Cu) phase, resulting in the formation of distinct microstructural zones in the developed microstructure of the flip-chip solder joint. 相似文献
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Fabrication and thermal analysis of flip-chip light-emitting diodes with different numbers of Au stub bumps 总被引:1,自引:0,他引:1
Cheng-Chen Lin Liann-Be Chang Chia-Yi Yen Chung-Yi Tang Mu-Jen Lai 《Microelectronics Reliability》2010,50(5):683-687
The thermal performance of flip-chip (FC) light-emitting diodes (LEDs) with different numbers of Au stub bumps has been investigated by using thermosonic bonder. The LEDs were mounted on the aluminium nitride (AlN) sub-mounts which have superior thermal conductivity (230 W/mK), and the high power Chip-on-Plate (COP) package was proposed to be used for our measurement. In order to understand the thermal performance of the high power FC-LEDs, the experimental measurement and finite-element model (FRM) numerical simulation have been used. It is found that the thermal performance of our 1 × 1 mm2 FC-LEDs can only be improved when using at least 6 Au stub bumps as interconnected metals. Moreover, the surface temperature of FC-LEDs is significantly reduced while using 20 Au stub bumps. 相似文献
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Effect of silver content on thermal fatigue life of Sn-xAg-0.5Cu flip-chip interconnects 总被引:5,自引:0,他引:5
Shinichi Terashima Yoshiharu Kariya Takuya Hosoi Masamoto Tanaka 《Journal of Electronic Materials》2003,32(12):1527-1533
The thermal fatigue properties of Sn-xAg-0.5Cu (x=1, 2, 3, and 4 in mass%) flip-chip interconnects were investigated to study
the effect of silver content on thermal fatigue endurance. The solder joints with lower silver context (x=1 and 2) had a greater
failure rate compared to those with higher silver content (x=3 and 4) in thermal fatigue testing. Cracks developed in the
solders near the solder/chip interface for all joints tested. This crack propagation may be mainly governed by the nature
of the solders themselves because the strain-concentrated area was similar for tested alloys independent of the silver content.
From the microstructural observation, the fracture was a mixed mode, transgranular and intergranular, independent of the silver
content. Higher silver content alloys (x=3 and 4) had finer Sn grains before thermal cycling according to the dispersion of
the Ag3Sn intermetallic compound, and even after the cycling, they suppressed microstructural coarsening, which degrades the fatigue
resistance. The fatigue endurance of the solder joints was strongly correlated to the silver content, and solder joints with
higher silver content had better fatigue resistance. 相似文献
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Chang S.J. Chang C.S. Su Y.K. Lee C.T. Chen W.S. Shen C.F. Hsu Y.P. Shei S.C. Lo H.M. 《Advanced Packaging, IEEE Transactions on》2005,28(2):273-277
Nitride-based flip-chip indium-tin-oxide (ITO) light-emitting diodes (LEDs) were successfully fabricated. It was found that the forward voltage and the 20 mA output power of the flip-chip ITO LED were 3.32 V and 14.5 mW, respectively. Although the operation voltage of such a flip-chip ITO LED was slightly larger, it was found that its output power was much larger than those of conventional nonflip-chip LEDs. It was also found that flip-chip ITO LEDs were more reliable. 相似文献