超薄型高容量刻蚀箔钽阳极电容器的制备

Preparation of ultra-thin,high-capacity etched foil-based tantalum anode capacitors

埋入式电容技术在缩小设备体积、降低功耗和提升性能上具有巨大优势。然而,目前商用的电容器的电容密度小、厚度大、成本高或无法与印刷电路板制造相兼容,为了解决这个问题,提出了一种超薄型高容量刻蚀箔钽阳极电容器的制备工艺,以脉冲直流为电流源对钽箔进行电化学刻蚀,大幅提升了钽箔的比表面积,在10V电压下阳极氧化后的比容可达550 nF/mm2。同时,以刻蚀钽箔为基底制备了高质量的钽阳极氧化膜,所形成的化成箔在9 V电压下的漏电流密度仅为24 nA/cm^(2)。固态聚合物阴极由固态钽电容器在PEDOT:PSS的水分散液中浸渍多次而形成,所制备的固态钽电解电容器厚度不足50μm,且表现出优良的频率特性。其等效串联电阻(100 kHz)低至19.2 mΩ,约为日本松下聚合物钽电容器的1/5,在1~100 kHz频率范围内的电容量保持率可达75.5%,与日本松下聚合物钽电容器相比提升55%以上。基于电化学刻蚀的箔式钽电解电容器将进一步推动钽电解电容器的小型化和轻薄化发展,并为埋入式电容技术开辟新的思路。

Embedded capacitor technology offers tremendous advantages in reducing device size,lowering power consumption and improving performance.However,current commercial available capacitors suffer from low capacitance density,high thickness,high cost or incompatibility with PCB manufacturing.In order to solve the above problems,this paper proposed a preparation process for ultra-thin high-capacity etched foil tantalum anode capacitors.Electrochemical etching of tantalum foil was carried out using pulsed DC as the current source,which substantially enhanced the specific surface area of the tantalum foil,and the specific capacitance of the anodized tantalum foil at 10 V could reach up to 550 nF/mm2.Meanwhile,high-quality tantalum anodic oxide film growth was carried out with etched tantalum foil as the substrate,and the leakage current density of the prepared tantalum oxide film was only 24 nA/cm^(2)at 9 V.The solid polymer cathode was formed by impregnating the solid tantalum capacitor in an aqueous dispersion of PEDOT:PSS for several times,and the thickness of the prepared solid tantalum capacitor was less than 50μm and exhibited excellent frequency characteristics.Its ESR(100 kHz)is as low to 19.2 mΩ,which is about 1/5 of that of Panasonic polymer tantalum capacitor(Panasonic polymer TC),and its capacitance retention in the frequency range of 1~100 kHz is up to 75.5%,which is an improvement of more than 55%compared with Panasonic polymer TC.Foil tantalum electrolytic capacitors based on electrochemical etching will further promote the development of miniaturization and thinness of tantalum electrolytic capacitors,and open up a new idea for embedded capacitor technology.