Parylene敷形涂层绝缘性能研究

聚对二甲苯(Parylene)是一种性能优异的敷形涂层材料,在航空、航天、电子领域的应用前景非常广泛。文中介绍了Parylene涂层绝缘性能的试验方法和试验过程,使用真空气相沉积技术制备了Parylene C、Parylene N、Parylene D涂层,对3种涂层不同厚度情况下的绝缘性能进行了比较,研究了涂层在常态下和温度冲击、湿热试验后的绝缘性能变化情况。为Parylene涂层在电子组件防护中的应用提供了技术支撑。     

Parylene在雷达产品中的应用探讨

介绍了雷达在严酷的环境条件下"三防"的重要性,列举了聚合物Parylene的特点,阐述了Parylene涂覆所采取的气相沉积原理和制备工艺.对Parylene涂层的性能与环氧涂层、有机硅涂层、聚氨酯涂层的性能进行了对比分析和探讨;并针对雷达的微波组件、数字电路组件、高功率组件等电子设备,分析了Parylene涂层应用优势.     

Parylene薄膜及其在MEMS中的应用

介绍了聚合物Parylene,包括其制备工艺和Parylene薄膜的图形化。着重介绍了Parylene在微流体系统的应用,包括微阀、微泵和微通道;在可植入微系统中的应用,包括人工耳蜗和视网膜假体。近来的研究表明,基于Parylene的MEMS微器件广泛应用在各种MEMS微结构、微传感器和微驱动器上,Parylene在各种完全集成微系统应用中将具有更加诱人的前景。     

浅析铁氧体-左手结构在微波领域中的应用

左手材料具有负介电常数和负磁导率的电磁特性,铁氧体具有负磁导率的电磁特性。因此,铁氧体-左手结构可以设计成负介电常数材料,近年来成为备受关注的研究课题,主要应用于隔离器、滤波器和移相器,在微波系统中具有很大的应用前景。文中介绍了铁氧体-左手结构的基本理论和性能特点,并对其在微波领域中的应用进行了试探性的分析。     

左手结构及其在天线微波领域中的应用

左手材料因其具有介电常数和磁导率同时为负值的电磁特性,近年来得到科学界的广泛关注。基于微带线等传输线结构所构成的左手材料与传统右手材料相比传输相移特性亦有不同,因此在天线微波系统中具有很大的应用潜力。文中介绍了这类左手传输结构的基本设计理论和性能特点,并对其在未来天线微波领域中的应用进行了探讨。     

Parylene高频电路防护工艺研究进展

从前处理、升华温度、裂解温度、沉积压力、基体温度和膜层厚度等方面讨论了Parylene处理技术在国内外高频电路防护方面的应用概况。重点介绍了这些工艺要素与Parylene膜层性能的相关性,并指出了膜层厚度及均匀度是影响高频电路防护的关键因素,膜层厚度需要通过试验进行确定,简要论述了Parylene膜层的沉积机理与Par...     

Parylene在毫米波MMIC电路防护上的应用研究

为了验证Parylene N在毫米波电路防护上应用的可行性,对35 GHz的薄膜滤波器和Ka频段的低噪声放大器进行了Parylene处理。测试结果表明,5μm的Parylene N膜层使薄膜滤波器中心频率下偏了约0.4%,10μm膜层使其中心频率下偏了约0.7%;5μm的Parylene N膜层使低噪放的噪声系数略有增大、增益略有降低。最后,对Parylene处理后的低噪放进行了湿热试验,高、低温贮存试验,发现其噪声系数曲线、增益曲线与试验前的走势一致性较好。因而,Parylene处理技术在毫米波电路防护上的应用是可行的。     

镁合金抗腐蚀复合表面处理工艺技术

镁合金由于具有优良的性能而广泛应用于航空、航天、兵器、汽车、电子等领域的结构件中,是武器装备减重的理想材料,但其较差的抗腐蚀性能又使其推广应用受到限制.根据镁合金的腐蚀类型及原理,提出了阳极氧化与派拉纶(Parylene C)的表面处理复合工艺途径和方法,并对工艺制备样品进行了测定.结果表明:采用阳极氧化与派拉纶的复合工艺技术,可提高其耐蚀性,耐盐雾能力达到48 h,满足军用电子产品环境适应性要求.     

铁电局域场增强低维材料光电探测器研究进展（特邀）

光电探测器在通讯、环境、健康和国防等日常生活及国家安全等领域中应用广泛。随着时代的发展,对光电探测器在灵敏度、响应速度及波长范围等方面的性能要求与日俱增。低维材料独特的电学及光电特性使其在光电子器件领域具有重要的应用前景。为了充分利用低维材料的优势,克服其暗电流大、吸收率低的不足,研究人员提出将铁电材料与低维材料结合,利用铁电材料的剩余极化作用形成强局域场调控载流子浓度以提高低维材料的光电探测能力。文中总结了近年来铁电局域场增强低维材料光电探测器的研究成果,介绍了铁电材料对一维纳米线、二维材料以及低维结型器件的调控和性能提升方面的相关研究。最后,对铁电局域场增强低维材料光电探测器的发展趋势进行了简要的总结和展望。     

SnSe的制备方法、热电性能及潜在应用

硒化锡(SnSe)具有极低热导率、高功率因子和高热电优值,是一种性能优异的热电材料。SnSe的热电性能与其结构和掺杂状态密切相关。从SnSe的基本特性出发,介绍了SnSe的典型制备方法,综述了SnSe的热电性能及光(热)电性能,讨论了SnSe在光伏、锂离子电池、柔性热电器件及相变存储器等领域的潜在应用,总结了目前SnSe研究中存在的问题,并对提高其低温热电性能的方法进行了展望。     

Surface reaction and stability of parylene N and F thin films at elevated temperatures

The morphology and chemical structure of Parylene F and Parylene N films annealed in air, N₂, and vacuum were examined. The decomposition temperatures of Parylene N in air, N₂, and vacuum were determined to be 175,350, and 425°C, respectively. The decomposition temperatures of Parylene F in air and N₂ were determined to be 400 and 500°C, respectively. For both materials, the decomposition process with and without the presence of O is different. In the case of Parylene N, O diffuses into the materials and reacts with the C in the polymer. In the case of Parylene F, no reaction products with O are observed on the surface. Annealing at the decomposition temperature resulted in the decomposition of -CF₂- functional groups to -CF- functional groups in the Parylene F. Thicker films,< μ, of either material cracked during annealing while films <0.5 μ, remained smooth and transparent. Pinholes were also observed in the Parylene F film deposited using the Gorham method after annealing.     

基于聚合物介质的低温硅硅键合研究

聚合物低温键合技术是MEMS器件圆片级封装的一项关键技术。以苯并环丁烯(BCB)、聚对二甲苯(Parylene)、聚酰亚胺(Polyimide)、有机玻璃(PMMA)作为键合介质,对键合的温度、压力、气氛、强度等工艺参数进行了研究,并分析了其优缺点。通过改变Parylene的旋涂、键合温度、键合压力、键合时间等工艺参数进行了优化实验。结果表明,在230 ℃的低温键合条件下封装后的MEMS器件具有良好的键合强度(＞3.600 MPa),可满足MEMS器件圆片级封装要求。     

Novel bi-layer conformal coating for reliability withouthermeticity MEMS encapsulation

A flexible, smooth, and low profile conformal coating was developed to accomplish the encapsulation of a microelectromechanical system (MEMS) device that will be applied to sense the static pressure on aircraft during real flight testing. The encapsulant should be able to protect the MEMS device and the multichip module (MCM) from adverse environmental conditions, i.e., mechanical shock, temperature fluctuation, engine fuel and oil contamination, and moisture/mobile ion permeation. Presently, conventional packaging schemes for electronics cannot satisfy this specific outdoor application, and a new encapsulation combination has been designed in accord with the requirement of reliability without hermeticity (RWOH). A bi-layer structure was selected because of property limitations of a single material. Pliable elastomeric silicones are typically flexible, water repellent, and abrasion resistant. The silicone encapsulant will be first applied to planarize the MEMS surface and function as durable dielectric insulation, stress-relief, and shock/vibration absorbers over a wide humidity/temperature range. To compensate for the deficiency of silicone on engine fuel/oil contamination, Parylene C is to be deposited afterward. This bi-layer coating can achieve excellent bulk properties, such as moisture and mobile ion barrier resistance, chemical compatibility, and electrical insulation characteristics. However, the poor adhesion of Parylene C to silicone greatly restricts its application. To address this problem, silane coupling agents were used as an adhesion promoter. Significant adhesion improvement was achieved by placing an interlayer silane coupling agent to provide interfacial bonding to the silicone elastomeric surface and the Parylene C film. Furthermore, a possible mechanism of adhesion enhancement will also be presented in this study     

印制电路组件三防涂覆工艺研究

对于特殊环境条件下使用的电子产品,三防涂覆可以对印制电路组件进行有效的防护.针对C型聚对二甲苯气相真空沉积涂覆技术,通过印制电路组件三防涂覆工艺研究及测试,验证了涂覆后的绝缘、耐压电性能等指标.结合印制电路组件涂覆后的返修,经过实验对比,确定了去涂覆的工艺方法.     

基于 Parylene 膜的法 珀干涉型光纤超声水听器

针对高强度聚焦超声(HIFU)声场测量,提出并研究了一种基于Parylene膜的法-珀干涉型光纤水听器。采用真空气相沉积法在光纤的端面蒸镀Parylene膜构成光纤水听器的法-珀腔,分析了光纤水听器的传感原理和解调原理,建立了HIFU声场检测的实验系统。实验结果表明,基于Parylene膜的法-珀干涉型光纤水听器能准确传感超声信号,其输出与换能器驱动电压的非线性度小于0.01,且与聚偏氟乙烯(PVDF)针式水听器的测量结果基本一致。     

Evaluation and characterization of reliable non-hermetic conformal coatings for microelectromechanical system (MEMS) device encapsulation

The thrust of this project was to evaluate commercial conformal encapsulation candidates for low cost aerospace applications. The candidate conformal coatings evaluated in this study included silicone elastomers, epoxies, and Parylenes with bi-layer or tri-layer designs. Properties characterized in this study included mobile ion permeation and moisture ingress resistance, interfacial adhesion variation through thermal shock cycling and 85/spl deg/C/85% RH aging. Surface Insulation Resistance (SIR), Triple Track Resistance (TTR) and die shear strength were used for the corresponding electrical and physical property characterizations. Parylene F displayed excellent properties for environmental protection. Silicone elastomers displayed less resistance to the harsh environment as compared to the Parylene family (N, C, D types), but it could provide advantages for low residual stress applications. The change in adhesion strength between Parylene C and silicone elastomers after exposure to thermal shock cycling or 85/spl deg/C/85%RH aging for different time periods were conducted from die shear test in terms of the interfacial failure. SIR values of all the candidate materials after 1000 h exposure to 85/spl deg/C/85%RH, with 100 V dc for resistance measurement, range from 1/spl times/10/sup 8/-1/spl times/10/sup 9/ /spl Omega/. Leakage current values after 1000 h exposure to 85/spl deg/C/85%RH, 175 V bias, are in the range of 10/sup -9/ to 10/sup -11/ Amp. The bi- or tri-layer conformal coating combination investigated in this study showed significant promise for encapsulation of the microelectromechanical system (MEMS) devices.     

太赫兹雷达及其隐身技术

近十多年来,太赫兹波技术领域基础研究的蓬勃发展带动了其应用领域的迅速扩大。本文主要介绍了应用于军事领域的太赫兹雷达的特点、国内外研究情况和存在问题,以及应用于隐身技术领域的泡沫型太赫兹吸波材料、太赫兹吸波涂层、左手材料的研究进展。