基于UV-LIGA工艺的500GHz定向耦合器制造

Terahertz (THz) technology is in the cross field of electronics and photonics. With many unique properties, THz has important scientific value and broad application prospects in radar imaging, material analysis, environment monitoring and high capacity communication etc. The application of directional couplers is very extensive in terahertz system, it can be used in signal extraction , separation and mixing, signal sampling and monitoring of transmitter, and also can be used as a reflection power meter, etc. As one of the core devices , the performance of directional couplers is directly related to the whole index of terahertz circuit system. Since the size of the terahertz devices is in tens of microns to millimeter level, the traditional machining technology is difficult to meet the requirements of machining precision and even is not be able to succeed. Based on the great advantages of UV Liga technology in the terahertz device processing, this project intends to adopt UV-Liga process to manufacture 500 GHZ directional coupler. When compatible with the traditional machining technology at the same time, UV-LIGA technology overcomed shortcomings in traditional machining process such as the great error and large surface roughness , solved technical problems in the lithography, electroforming and bonding critical process steps .put forward a technological process which is suitable for high precision batch processing , and produced a integrated THz directional coupler with to a large bandwidth and good directional property.

太赫兹（THz）技术处于电子学与光子学领域的交叉领域，由于THz具有很多独特的性质，使得它在如雷达成像、材料分析、环境监测以及大容量通讯等方面，都具有重大的科学价值和广阔的应用前景。定向耦合器在太赫兹系统中应用非常广泛，它既可以用作信号提取、分离和混合，发射机的信号取样和监测，还可以作反射功率计等，作为核心器件之一，其性能直接关系到整个太赫兹电路系统的指标。太赫兹器件的尺寸在数十微米到毫米量级，传统的机械加工技术很难达到加工精度要求，甚至无法加工。基于UV-LIGA的技术在太赫兹器件的加工方面具有巨大的优势。本项目拟采用UV-LIGA工艺制造中心频率在500GHz的定向耦合器，与传统机械加工技术相兼容的同时，克服了传统机械加工手段误差大、表面粗糙度大等缺点，解决光刻、电铸和键合等关键工艺步骤难题，提出适宜于高精度大批量加工工艺流程，制作一种带宽大、定向性好、可集成的THz定向耦合器。

项目以太赫兹技术为应用背景，从定向耦合器的设计理论出发，建立了多孔耦合型波导定向耦合器模型，并对其进行仿真优化和制作测试。通过对矩形波导和耦合理论的分析，利用上、下排列的波导之间的多个耦合孔来实现功率分配，通过电磁仿真软件HFSS进行建模分析，确定了耦合器的最优尺寸。针对太赫兹器件尺寸小、难加工的难题，采用基于UV-LIGA工艺的三维金属加工技术，经过光刻、电铸和键合等关键工艺，封装得到了形貌完整的太赫兹多孔波导定向耦合器。同时，搭建了波导定向耦合器测试平台，完成了耦合器的结构特性测试和电磁性能测试。结果表明制备得到的耦合器结构完整、孔洞清晰、侧壁陡直，在300-500 GHz的频段内方向性优于20 dB，回波损耗和隔离度小于25 dB，实现了申请书中提出的各项预期指标。此多孔波导实现耦合器具有结构紧凑、工作频带宽、方向性强等优点，在雷达、通信、测量等领域发挥重要作用，该工艺也对大批量高精度加工太赫兹器件具有一定的参考意义。