一种新型结构的湿度传感器

本文提出了一种以聚酰亚胺为介质膜的电容式湿度传感器.它的工作原理是,在不同的湿度环境下,聚酰亚胺—水系统介电常数改变引起传感器电容的变化.该传感器具有工艺简单、体积小、灵敏度高、响应快等优点.该文介绍了它的结构、制造工艺和试验结果.     

CMOS工艺兼容的单片集成湿度传感器

设计并制备了一个CMOS工艺兼容的集成湿度传感器,将湿度传感器与CMOS测量电路集成在同一芯片上.片上集成的湿度传感器为叉指电容式,感湿介质为聚酰亚胺,本文给出了相应的感湿模型.针对湿度传感器在全量程电容变化量较小的特点,本文采用开关电容电路作为片上微电容测量电路,讨论了电路的原理并给出了模拟结果.芯片采用3μm多晶硅栅标准CMOS工艺进行流水.测量结果表明,片上集成湿度传感器在5～35℃有较好的直流输出特性,并且长时间稳定性良好.     

CMOS工艺兼容的单片集成湿度传感器

设计并制备了一个CMOS工艺兼容的集成湿度传感器,将湿度传感器与CMOS测量电路集成在同一芯片上.片上集成的湿度传感器为叉指电容式,感湿介质为聚酰亚胺,本文给出了相应的感湿模型.针对湿度传感器在全量程电容变化量较小的特点,本文采用开关电容电路作为片上微电容测量电路,讨论了电路的原理并给出了模拟结果.芯片采用3μm多晶硅栅标准CMOS工艺进行流水.测量结果表明,片上集成湿度传感器在5～35℃有较好的直流输出特性,并且长时间稳定性良好.     

一种基于微加工技术的微型电场传感器的设计与制造

一种新型的，以压电陶瓷条为驱动、硅为屏蔽和感应电极的微型电场传感器。此种传感器利用了新型的电场感应模式，采用微加工技术制造，使其具备体积小、重量轻、功耗低、便于与其它器件集成等特点，而且制作工艺简单，成本较低。本文阐述了此种传感器的工作原理，并通过计算机模拟验证了可行性，同时描述了新型传感器的结构设计和加工工艺过程。实验数据表明，新型电场传感器的分辨率达到250V／m。     

基于CMOS工艺的硅基PI湿度传感器的研制

在国内外湿度传感器研究的基础上,基于Si CMOS工艺研制出了以聚酰亚胺(PI)为感湿介质的电容型相对湿度传感器.并对其结构进行了理论分析,仔细确定了湿度传感器的工艺步骤和版图设计.对其测量范围、湿滞和响应时间等特性参数进行了详细的测试.通过实验结果与模拟结果的对比分析,给出了该实验中存在的问题和改进意见,以便在今后的研究中加强这方面的工作.     

聚酰亚胺表面钝化工艺及对半导体器件可靠性和稳定性的影响

聚酰亚胺是一种新型耐高温钝化材料,涂敷在硅表面上形成的薄膜带有负电荷,可以削弱硅表面电势,此外聚酰亚胺还具有物理和化学性能稳定,耐辐射、电绝缘性好、韧件强、工艺简单、成本低,适合于批量生产等特点.本文将对用于硅台面和平面技术中的聚酰亚胺表面钝化工艺效果进行分析和介绍,以确定聚酰亚胺钝化与器件的可靠性和稳定性的关系.     

一种用于湿度监测的LC无线无源传感器的制备与测试

提出了一种采用丝网印刷和亚胺化工艺制备的LC无线无源技术的二硫化钼(MoS2)/聚酰亚胺(PI)湿度传感器。对比了不同超声时间下的二硫化钼/聚酰亚胺复合材料的湿度敏感性能,得出对湿度最灵敏的材料为超声4 h的二硫化钼/聚酰亚胺材料。测试结果表明,制备的器件在量程10%RH～95%RH内具有较好的频率响应,频率变化值为6.205 MHz;在高湿度范围内(60%RH～95%RH),传感器的灵敏度可达153.59 kHz/%RH。此外,该传感器的响应和恢复时间分别为7.2 s和10.4 s,迟滞性误差约为5%RH且具有较好的稳定性。该传感器可广泛应用于化学合成和矿井环境等领域的湿度监测。     

高灵敏度塑料光纤湿度传感器

为了提高塑料光纤湿度传感器的灵敏度,该文利用商用塑料光纤、聚砜、二氧化锗(GeO₂)和聚酰亚胺构建了一种新型结构的塑料光纤湿度传感器。首先将长度为0.5 m的商用塑料光纤中心部分(长5 cm)包层去除,并弯曲成U形(弯曲半径为2 cm),再将聚砜与GeO₂的混合物涂覆在商用光纤纤芯表面,然后将涂覆聚砜与GeO₂的塑料光纤在70 ℃下干燥10 h,最后涂覆上聚酰亚胺湿敏材料,在60 ℃下干燥后形成塑料光纤湿度传感器。实验研究了不同涂覆对塑料光纤传感器光传输特性及其灵敏度的影响,实验结果表明,在温度40 ℃、相对湿度10%RH~80%RH下,当塑料光纤纤芯直径为900 μm、聚砜与GeO₂涂覆层厚200 μm、聚酰亚胺湿敏膜厚 20 μm时,传感器对湿度的响应灵敏度可达到-0.9 nW/(1%RH),是将20 μm聚酰亚胺湿敏材料涂覆在1 500 μm塑料光纤纤芯表面响应灵敏度的6.9倍。     

一种新型的CMOS集成湿度传感器

利用MEMS技术 ,对一种新型CMOS湿度传感器进行理论分析、模拟以及结果讨论。该湿度传感器采用标准CMOS工艺制造 ,采用梳状铝电极结构、梳状多晶硅加热结构 ,衬底接地 ,感湿介质采用聚酰亚胺 ,利用商业软件Coventor进行模拟绘制出敏感电容与相对湿度的曲线图。接口电路采用开关电容电路 ,输出可测电压信号 ,利用Microsim公司的Pspice模拟电路得到相对湿度与输出电压曲线关系     

新型聚酰亚胺图形化工艺制备视网膜电极

介绍了一种新型的、基于Cu牺牲层的聚酰亚胺图形化方法制备视网膜电极的MEMS工艺,并对其电化学性能进行了表征。该工艺创新性地以Cu作为衬底聚酰亚胺图形化的牺牲层,以PDMS(聚二甲基硅氧烷)作为剥离层,以聚酰亚胺作为封装材料,以惰性金属作为电极保护层材料,通过电铸、牺牲层和抛光打磨工艺,制备出可以自释放的柔性视网膜电极;随后,对器件进行封装,并对器件的表面形貌和电学性能进行了表征。视网膜电极器件厚度50μm,电路线宽50μm,阻抗104～105Ω。通过该工艺制得的人造视网膜电极具有柔软无伤害、生物相容以及低成本的优点。     

In situ measurement of mechanical properties of polyimide filmsusing micromachined resonant string structures

Two in situ measurement schemes, using micromachined resonant string structures, for the measurement of the polyimide residual stress and polyimide/metal adhesion durability have been developed. The residual stress of polyimide films, DuPont PI-2555 and PI-2611, have been measured using a bulk micromachined string structure. According to the Rayleigh's method, the resonant frequency of a polyimide string can be related to the film stress. By measuring the resonant frequency of these polyimide strings, the residual stresses have been calculated. The measurement results of various strings have been compared with conventional measurement results, which shows that they are in good agreement. Also, a noble scheme to quantize the adhesion durability between a polyimide film and a metal film has been developed. This scheme is based on a polyimide/metal bimorph string structures, fabricated using a surface micromachining technique, vibrating with an alternating potential. The change of resonance profile of this string structure can be related to the degradation of adhesion strength at the polyimide/metal interface. Various polyimide/gold string structures have been fabricated using a surface micromachining with Cu sacrificial layers, and the resonant qualities have been monitored. Notable changes of resonant Q-factor and resonant frequency, due to the degradation of adhesion between the metal and polyimide, have been observed after 10 ⁸ cycles (string vibration) for the polyimide/gold bimorph strings. The changes of resonant Q-factor and resonant frequency over a time period (vibration cycles) have been monitored     

Ultra-violet direct patterning of metal on polyimide

Copper micro-patterns have been fabricated on polyimide substrates by ultra-violet (UV) lithography without the use of evaporation techniques or photoresist materials. Using a photoreactive polymer-reducing agent, methoxy poly(ethylene glycol) (MPEG) as a thin film coating, a novel light-directed metal-patterning method in air atmosphere was realised. The interaction of UV light and MPEG in ethanol film enabled the photoreduction of mobile silver ions available within the surface-modified polyimide substrates. The silver nanoparticle patterns thus formed served as active catalytic seed layers for subsequent electroless copper plating. Narrow copper tracks with low resistivity close to that of bulk copper were achieved. MPEG is a nontoxic, low cost and commercially available polymer which can be easily spin-coated and washed off after the patterning process. These attractive properties of MPEG together with its photoreactivity provide great potential for developments of UV direct-metallisation methods.     

多驱动电极垂直限幅振动式微型电场传感器

设计了一种具有四个驱动电极和独特支撑结构并基于MEMS技术制作的微型电场传感器。该传感器的四个驱动电极具有完全相同的形状，在使用时可以将其中的两个用作驱动，另外两个作为振动检测电极．监控振动情况。传感器的支撑结构可以限制振动幅度，使传感器在脉冲信号驱动下也能稳定工作。因此该电场传感器除了具备其它微型电场传感器的优点以外．还可以根据应用场合的需要选择不同的驱动模式。从而可以根据具体应用的要求，使用较简单的测试系统减轻重量，或使用较复杂的测试系统提高测试的精度和稳定性。本文介绍了此种传感器的结构，工作原理以及三种不同的驱动模式的实现方法．并讨论了不同模式的应用场合。     

用条纹时问平均法分析薄膜振动模式

提出一种对薄膜的振动模式进行定性分析和识别的方法一结构光条纹时间平均法.该方法采用结构光三维传感技术,用低帧频商用CCD相机记录由光栅投影到振动薄膜而上、因薄膜振动导致条纹局邴模糊的一系列变形正弦条纹,经过傅里叶变换、频谱滤波、逆傅里叶变换、取模等处理得到被测薄膜的振动模式分布.本文给出了该方法的理论分析,推导了相应的计算公式.计算机模拟和实验验证了该方法的可行性:能够对在不同激励频率下薄膜的振动模式进行定性分析和识别.在实验中,如果连续改变振动物体的振动激励频率,可以清楚地观察到物体振动模式的变换过程.实验证明,本文方法具有数据获取速度快,全场测量,实验装置简单等优点.     

Facile chemical method of etching polyimide films for failure analysis (FA) applications and its etching mechanism studies

A new strategy has been developed for discovering a novel/facile way of etching polyimide film for FA application. The aromatic polyimide synthesized from pyromellitic dianhydride and 2,2′-dimethyl-4,4′-diaminobiphenyl in the presence of an acid catalyst. This polyimide film was used to study its physical attributes and the chemical etching rate which can be evaluated in microelectronic package application as dielectric film. Chemical etching rates of polyimide film by an alkaline etching solution with the presence of different kinds of etchants were studied by film-thickness measurement and UV absorption spectroscopy of dispersible etching residue. The etching rate of polyimide film in alkaline ethylenediamine solution is highest among the etching solution studied in the present experiment. If an external bias voltage was applied during etching, the etching rate was increased. The effect of temperature, solubility of the etchant was also discussed. The presence of a radical in the process of etching reveals that the etching reaction is a type of radical chain reaction. It was found that the deprocessing technique (drenched alkaline aqueous solution of ethylenediamine and then instantaneously combined with mix acid (2:1 Nitric 90% fuming to Sulfuric mix at 40 °C)) could be extended to remove polyimide in different package geometry and different thickness of film.     

A cost-effective flexible MEMS technique for temperature sensing

A simplified, cost-effective flexible micro-electronic-mechanical systems (MEMS) technology has been developed for realizing a temperature-sensing array on a flexible polyimide substrate. The fabrication technique utilized liquid polyimide to form flexible film on the rigid silicon wafer using a temporary carrier during the fabrication. The platinum thin film is employed as temperature sensitive material and 8×8 temperature-sensing arrays were micromachined on the polyimide, from which the silicon wafer carrier was removed at the end of fabrication. The platinum thin film temperature sensor exhibits excellent linearity and its temperature coefficient of resistance reaches 0.00291 °C⁻¹. Because of the effective thermal isolation, the flexible temperature sensors show a high sensitivity of 1.12 Ω/°C at 10 mA to the constant drive current. The flexible MEMS technology based on liquid polyimide enables the development of flexible, compliant, robust, and multi-modal sensor skins for many other important applications, such as robotics, biomedicine, and wearable microsystems.     

Thermoelectric power of Bi<Subscript>92</Subscript>Sb<Subscript>8</Subscript> and Bi<Subscript>85</Subscript>Sb<Subscript>15</Subscript> thin films

The results of studying the galvanomagnetic and thermoelectric properties of thin block Bi₉₂Sb₈ and Bi₈₅Sb₁₅ films on mica and polyimide substrates are presented. The method used for measuring the thermoelectric power allowed us to study the temperature dependence the thermoelectric power, without introducing additional deformations into the substrate–film system. A significant difference in the temperature dependences of the galvanomagnetic and thermoelectric properties of films on mica and polyimide is found. The free charge-carrier concentrations and mobilities in the films on mica and polyimide and levels of the chemical potential for electrons and holes are calculated within the two-band approximation. The difference in the charge-carrier parameters for films on mica and polyimide is associated with strains in the film–substrate system.     

一种聚酰亚胺超低热导红外热敏悬浮微桥

热导极为微小的热敏悬空微桥结构的制作是集成非致冷热成像探测阵列热敏感单元研究的核心。由于没有现成的将聚酰亚胺制成微桥的工艺,采用准分子激光微刻蚀技术,使用聚酰亚胺材料,并采用铂作为敏感材料来制作微桥。对所制作的铂/聚酰亚胺微桥原理性样件的初步测试表明,铂/聚酰亚胺微桥的热导约3.98×10-7W/K,与理论计算值接近。铂薄膜与聚酰亚胺微桥附着良好,工艺可行。在0～10V的驱动电压下可观察到铂/聚酰亚胺微桥样件明显的自热效应,其电加热响应时间小于100ms。     

Processing thick multilevel polyimide films for 3-D stacked memory

This paper discusses thick polyimide film processing for a three-dimensional (3-D) semiconductor chip-stacking application. The formation of a complex, multilevel via structure is demonstrated. The issues that arise in forming these vias relate to apply, develop, profile modification, and integration. Apply issues include “outgassing” defects, edge-bead effects, as well as the planarity and leveling of both resist and polyimide over deep-via structures. Develop issues pertain to the implementation of a thick resist process that increases the structural integrity of the resist and controls its breakage, and to a vacuum bake before applying resist, which reduces solvent absorption into the resist. Profile modification issues include rounding via edges while minimizing bulk polyimide loss and maintaining image-size control. Developer attack of the metal pads during wet processing is discussed and a solution is proposed. Finally, additional process-integration issues relating to polyimide-to-metal adhesion and composite stress levels of the multilayer thick films are presented     

Polyimide/Ta2O5/polyimide antiresonantreflecting optical waveguides

A novel antiresonant reflecting optical waveguide (ARROW) fabricated using both the organic and dielectric thin film technologies is presented for the first time. The ARROW consisted of the fluorinated polyimide and tantalum pentoxide (Ta₂O₅) hybrid layers deposited on a Si substrate. For TE polarized light, the propagation loss of the waveguide as low as 0.8 dB/cm is obtained at 632.8 nm. The propagation loss for TM polarized light is 2.7 dB/cm. Some design considerations of the hybrid ARROW are also discussed in this work