飞秒激光时空整形的电子动态调控微孔加工

微孔作为一种常见结构,被广泛应用于生物医疗、航空航天、三维封装等领域.飞秒激光具有的超短脉冲持续时间和超高峰值功率特性使其在高质量微孔加工方面具有独特优势.本文综述了近年来飞秒激光时空整形微孔加工方法及其应用,包括飞秒激光时空整形方法、时域/空域整形的电子动态调控微孔加工以及微孔在增透减反、切割以及油水分离、雾气收集、...     

低温共烧基板材料研究进展

LTCC是现代微电子封装中的重要组成部分,因性能优良而广泛应用于高速、高频系统.LTCC基板材料的性能决定封装的质量,材料的研究在LTCC的进展中发挥了重要作用.LTCC基板材料可分为两大类:玻璃/陶瓷和微晶玻璃.概述了各类基板材料的组成、性能和应用方面的情况,并介绍了各类材料研究的进展,指出了基板材料未来的发展方向.     

DBC电子封装基板研究进展

综述了DBC电子封装基板的研究进展,介绍了DBC电子封装基板材料的选择、敷电子封装中的使用特点,并展望了DBC电子封装基板的应用前景.     

大功率LED封装基板研究进展

随着大功率LED向高电流密度、高光通量发展,热流密度猛增使得LED散热问题日益严重。封装基板对LED的散热至关重要。在简介LED的封装结构及散热方式的基础上,分析总结了常见封装基板材料的性能参数,并对目前市场常见封装基板MCPCB、DBC、DAB、DPC、LTCC、HTCC、Al/SiC以及最近出现的新型材料基板的特征、制造工艺、应用等进行了综述。     

液晶聚合物薄膜在高频电子封装中的应用进展

系统地介绍了液晶聚合物(LCP)薄膜材料的特性,同时介绍了LCP覆铜板的3种生产方法,分析了作为基板材料与其他传统基板材料的优势,综述了近年来LCP薄膜作为微波和毫米波材料在系统级封装中的研究进展,并指出LCP薄膜是一种具有巨大发展潜力的高频电子封装材料。     

CO2激光加工微孔膜关键加工参数

目的解决CO_2激光加工微孔膜实际生产中难以快速、精确地确定不同孔径微孔加工参数的问题,指导微孔膜包装材料的工程应用。方法在激光功率为6~30 W、打孔时间为0.4~4 ms的条件下,加工厚度为0.04,0.06,0.07 mm的PP包装薄膜和厚度为0.035,0.05,0.07 mm的PE包装薄膜,测量微孔孔径、孔长,分析处理试验数据。结果在厚度为0.035~0.07 mm的PP/PE薄膜上加工出了直径为50~400μm微孔,在厚度为0.06 mm的PP薄膜上加工出了直径为53~257μm、孔长为100~161μm的微孔。结论激光加工微孔膜,孔径随激光功率、打孔时间的增加而增大,调节激光功率和打孔时间均可获得不同孔径微孔;加工PE薄膜所需的激光能量显著大于PP薄膜;薄膜厚度越大,打孔所需的激光能量越高;微孔孔长相对于薄膜厚度有所增加,且微孔孔径越大,孔长增量越大。     

玻璃纤维蜂窝复合材料在光伏电池组件中的应用分析

本文阐述了采用玻璃纤维蜂窝复合材料替代光伏组件的玻璃底衬基板，并利用特殊工艺对光伏组件进行封装，既可满足光伏组件底衬基板的性能要求，又可减轻光伏组件的重量，必将成为光伏组件层压封装的首选材料。     

大功率LED封装用散热铝基板的制备与性能研究

通过正交试验分析了阳极氧化法制备LED封装用铝基板过程中电流密度、硫酸质量浓度、温度和时间等因素对其热阻、厚度、绝缘电阻率的影响.得到了制备低热阻铝基板的最佳工艺参数.根据优化参数制备了阳极氧化铝基板,将LED分别封装在自制基板和深圳光恒光电公司提供的铝基板上,检测温度与时间变化的关系,结果表明,自制散热铝基板性能更优.     

LED封装基板研究新进展

基板散热是LED散热的最主要途径,其散热能力直接影响到LED器件的性能和可靠性。总结了LED封装基板材料的性能,综述了金属基板、陶瓷基板、硅基板和新型复合材料基板的研究进展,展望了功率型LED封装基板的应用和发展趋势。综合表明,MCPCB,DBC,DAB,DPC等基板各具优势,但DPC基板各种制备工艺参数合适,特别是铝碳化硅基板(Al/Si C)有着低原料成本、高导热、低密度和良好可塑性的显著优势,有望大面积推广应用。     

宽带驱动放大器MMIC的SMD封装

研究了一种采用Rogers 4003型有机基板材料和PCB工艺制造的MMIC一级封装结构,该封装结构与SMT工艺兼容,具有良好的散热性能和较低的成本,可用于X＆Ku波段驱动放大器芯片.采用三维电磁场仿真软件对封装结构进行了优化设计,制备了封装结构样品,并采用HP 8722D型高频网络分析仪实测了封装后的X＆Ku波段驱动放大器芯片性能.测试结果表明,在6～18GHz频段内,封装后芯片的增益维持在20dB以上,反射小于-10dB,性能与裸芯片十分接近.关键词:MMIC,封装,有机基板材料,SMT,三维电磁场仿真     

High-resolution, resistless patterning of indium-tin-oxide thin films using excimer laser projection annealing process

High-resolution, large-area patterning of indium-tin-oxide (ITO) thin film was demonstrated using an excimer laser projection crystallization process. After amorphous ITO (a-ITO) was deposited on a glass substrate, the a-ITO was selectively crystallized using an excimer laser scanning projection exposure system. Following the selective crystallization, the substrate was dipped in an etchant for an optimized time, resulting in formation of high-resolution patterns of polycrystalline ITO (p-ITO) on the substrate because the a-ITO has higher etch rate than the p-ITO. The p-ITO patterns were clean and sharp, and the pattern quality was suitable for production applications in the microelectronics industry.     

Fabrication of micro pin fins on inclined V-shaped microchannel walls via laser micromilling

A laser-micromilling process was developed for fabricating micro pin fins on inclined V-shaped microchannel walls for enhanced microchannel heat sinks. A pulsed nanosecond fiber laser was utilized. The feasibility and mechanism of the formation of micro pin fins on inclined microchannel walls were investigated for a wide range of processing parameters. The effects of the laser output power, scanning speed, and line spacing on the surface morphologies and geometric sizes of the micro-pin fins were comprehensively examined, together with the material removal mechanisms. Micro pin fins with acute cone tips were readily formed on the V-shaped microchannel walls via the piling of recast layers and the downflow of re-solidified materials in the laser-ablation process. The pin-fin height exhibited an increasing trend when the scanning speed increased from 100 mm/s to 300 mm/s, and it decreased continuously when the line spacing increased from 5 μm to 20 μm. The optimal processing parameters for preparing micro pin fins on V-shaped microchannels were found to be a laser output power of 21 W, scanning speed of 100–300 mm/s, and line spacing of 2–5 μm. Moreover, the V-shaped microchannels with micro pin fins induced a 7%–538% boiling heat-transfer enhancement over their counterpart without micro pin fins.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00382-x     

大功率CO2激光原位直接反应合成TiN/Ti 复合材料的研究

使用大功率CO₂激光原位直接反应合成TiN /Ti 复合材料, 分析了材料的微观结构、物相组成、成分及显微硬度分布。结果发现: 氮化层是富钛结构的, 由TiN 相和α-Ti 构成, TiN 以枝晶形式在氮化层均匀分布。材料横截面显微硬度连续变化。氮化层的氮化程度随激光作用时间的增加而增加, 辐照的激光能量密度越高, 氮化层的厚度越大。激光功率密度, 激光扫描速度, 氮气喷射压强分别为3. 35×105W·cm-2, 300mm·min-1, 0.35M Pa 时, 材料表面硬度值达到Hv1600, 氮化层的厚度有350Lm。      

Laser-machined piezoelectric cantilevers for mechanical energy harvesting

In this study, we report results on a piezoelectric- material-based mechanical energy-harvesting device that was fabricated by combining laser machining with microelectronics packaging technology. It was found that the laser-machining process did not have significant effect on the electrical properties of piezoelectric material. The fabricated device was tested in the low-frequency regime of 50 to 1000 Hz at constant force of 8 g (where g = 9.8 m/s(2)). The device was found to generate continuous power of 1.13 microW at 870 Hz across a 288.5 kOmega load with a power density of 301.3 microW/cm(3).     

Laser drilling of hollow sphere structures

A special composite and cellular material – the metallic hollow sphere structure (MHSS) – represents an advanced material. The core element of the structure is a hollow sphere with a wall out of porous steel. This shell allows a high geometric reproducibility. It is an interesting base material for lightweight design. However, processing technologies for further manufacturing of metallic hollow sphere structure are necessary. Laser beam drilling is a highly efficient technique with heat input concentrated locally at the structure. Laser drilling is applied to metallic hollow sphere structures. The influence of different geometries and joining technologies of the spheres on the drilling behaviour is investigated. Percussion drilling is used to form holes with a CO₂‐laser into the metallic hollow sphere structure. The investigated mean laser power is 400 W. Two different focal lenses with focal lengths of 5″ and 7.5″ allow investigations with different focal diameters and Rayleigh lengths. Diameter and roundness of the laser drilled holes are measured in five layers of different drill depths z. The maximum drilled depth is about 40 mm with a 5″ lense and about 50 mm with the f = 7.5″ lens. The relative roundness is determined and decreases with increasing drill depth. The diameter d(z) as a function of the drill depth follows the shape of an isophote, a line of constant intensity inside the laser beam. The brazed hollow sphere structures have considerably less drill depth than the sintered.     

The Effect of Laser Power,Traverse Velocity and Spot Size on the Peel Resistance of a Polypropylene/Adhesive Bond

The mean peel resistance force achieved with respect to variation in the laser power, incident spot traverse velocity and incident spot diameter between linear low density polyethylene film backed by a thin commercial adhesive coating that were bonded to a polypropylene (PP) substrate via thermal activation provided by a 27W CO₂ laser is discussed in this work. The results gathered for this work have been used to generate a novel empirical tool that predicts the CO₂ laser power required to achieve a viable adhesive bond for this material combination. This predictive tool will enable the packaging industry to achieve markedly increased financial yield, process efficiency, reduced material waste and process flexibility. A laser spot size‐dependent linear increase in laser line energy was necessary for this material combination, suggesting the minimal impact of thermal strain rate. Moreover, a high level of repeatability around this threshold laser line energy was indicated, suggesting that laser‐activated adhesive bonding of such polymer films is viable. The adhesion between the material combination trialled here responded linearly to thermal load. In particular, when using the smallest diameter laser spot, it is proposed that the resulting high irradiance caused film or adhesive material damage, thus resulting in reduced peel resistance force. The experimental work conducted indicated that the processing window of an incident CO₂ laser spot increases with respect to spot diameter, simultaneously yielding greater bond stability in the face of short‐term laser variance. © 2015 The Authors. Packaging Technology and Science published by John Wiley & Sons Ltd.     

Low-power-Consumption metal oxide NO2 gas sensor based on micro-heater and screen printing technology

An NO2 micro gas sensor was fabricated based on a micro-heater using tin oxide nano-powders for effective gas detection and monitoring system with low power consumption and high sensitivity. The processes of the fabrication were acceptable to the conventional CMOS processes for mass-production. Semiconducting SnO2 nano-powders were synthesized via the co-precipitation method; and to increase the sensitivity of the NO2 gas rare metal dopants were added. In the structure of the micro-heater, the resistances of two semi-circular Pt heaters were connected to the spreader for thermal uniformity. The resistance of each heater becomes an electrically equal Wheatstone-bridge, which was divided in half by the heat spreading structure. Based on the aforementioned design, a low-power-consumption micro-heater was fabricated using the CMOS-compatible MEMS processes. A bridge-type micro-heater based on the Si substrate was fabricated via surface micro-machining. The NO2 sensing properties of a screen-printed tin oxide thick film device were measured The micro gas sensors showed substantial sensitivity down to 0.5 ppm NO2 at a low power consumption (34.2 mW).     

基于工业合金激光熔覆制备Fe基非晶涂层

以FeCoCrMoCBY块体合金为熔覆材料,采用激光熔覆在低碳钢表面制备非晶涂层,探讨不同激光功率对涂层成形及组织的影响,通过显微硬度仪、电化学工作站测试涂层显微硬度及耐腐蚀性能。研究结果表明,其他参数不变,激光功率为17.6~20.8 W时,涂层成形良好,与基材呈典型冶金结合。随激光功率增加,涂层稀释率升高,裂纹倾向增大,非晶化程度降低。激光功率为17.6 W时,涂层主要由非晶组成,稀释率低于24.2%,结构致密,包括热影响区、熔合区和熔覆区;涂层平均显微硬度为1 330HV,约高于基材9倍,在3.5%NaCl溶液中的耐腐蚀性能明显优于316L不锈钢。     

Applications,materials, and fabrication of micro glass parts and devices: An overview

Material selection is a critical factor that affects the performance of devices and parts on a microscale. Glass is a candidate material for micro applications as it possesses notable characteristics like biocompatibility, optical transparency, mechanical rigidity, and thermal stability, to name a few. Glass-based micro parts and devices have been developed to accommodate various applications in various fields. The fields mentioned in this review article include medical, optics, metrology, microelectronics, micro-mechanisms, and microfluidics. The most significant parts and devices in each field are investigated in terms of their application, function, fabrication process and glass significance. In addition, an overview of glass materials and fabrication techniques on a micro-scale is further discussed. The review aims to shed light on the capabilities of glass as a material that has substantial potential to enhance the performance of micro parts/devices and clarify the associated challenges. Further advancements in micro-machining technologies could address one of the primary issues facing micro-glass applications in the future.     

Microstructure and micro‐hardness of in situ synthesized TiC particles reinforced Fe‐based alloy composite coating by laser cladding

A Fe‐based composite coating reinforced by in situ synthesized TiC particles was fabricated on Cr12MoV steel by using 6 KW fiber laser cladding. A serial of experiment has been carried out with different laser power, scanning speed, and powder feed rate, from which TiC could be in situ synthesized only in certain realms laser cladding parameters. X‐ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscope and a hardness tester are used to test the microstructure, micro‐hardness and component distribution. The coating is mainly composed of alpha ;‐Fe, TiC and Fe₃C. TiC particles were commonly precipitated in three kinds of morphologies, such as quadrangle, cluster, and flower‐like shape. The grains were refined, and there were no cracks and few stomas. Defect‐free coating with metallurgical joint to the substrate was obtained. TiC distributed more concentratively in the upper layers than the middle and bottom layers. From the surface of cladding layer 0.8 mm the highest micro‐hardness was up to HV930, obviously higher than that of the substrate.