折叠波导高频结构UV-LIGA技术研究

Fabrication of Folded Waveguide for Traveling Wave Tube by Ultra-Violet Lithography Galvanik Abformung

真空电子器件的频率越来越高,作为核心部件的折叠波导慢波结构由于具有独特的优点,在真空器件中必将得到广泛的应用。由于真空器件的尺寸与波长具有共渡性,频率越高,互作用结构的尺度越小,加工误差的要求越来越严格。传统的加工方法很难实现如此微小尺寸的结构,而UV-LIGA技术对于制造这种微型结构是一种很有前途的方法。本文以220GHz折叠波导为研究对象,在中科院电子所行波管设计、计算和仿真模拟软件IESTWT1.0平台上,进行了设计和仿真,对高频慢波结构的相关参数进行了优化,并开展了基于SU8厚胶采用嵌丝式UV-LIGA工艺制备折叠波导互作用结构的工艺实验,主要包括无氧铜WAFER制备、大厚度SU8胶匀胶工艺、光刻工艺、嵌丝工艺、电铸以及去胶工艺等参数的摸索。结果表明采用基于SU8系列光刻胶的UV-LIGA方法可以实现折叠波导慢波结构的制备。

The small-sized, folded waveguide （FWG） slow-wave structure, a component of traveling wave tube （TWT） operating at THz range, was successfully fabricated by ultra-violet lithography galvanikabformung （UV-LIGA）. The FWG was designed and simulated with the self-developed software IESTWT platform. The impact of the UV-LIGA conditions, including but not limited to the fabrication of oxygen-free copper wafer, coating and removal of thick SU8 pho- toresist, UV-exposure, monofilament embedment, electroplating, and degassing temperature and time, on the fabrication tol- erances and properties of the FWG was experimentally investigated, The prototyped FWG, fabricated with specifications： 50 W,20 dB at 220 GHz,channel radius of 0.09 ram,rectangle of 758μm×115 μm,and period of 235 μm,was experimen- tally characterized. The simulated and measured results show that the fine structure of the novel FWG displays nearly con- stant dispersion, high coupling impedance and low high-frequency loss.