Li Haiwang, Zhu Kaiyun, Xu Tiantong, Lei Kaibo, Xia Jingchao
National Key Laboratory of Science and Technology on Aero-Engine Aero-Thermodynamics, Beihang University, Beijing 100191, China.
Research Institute of Aero-Engine, Beihang University, Beijing 100076, China.
Micromachines (Basel). 2022 Dec 7;13(12):2162. doi: 10.3390/mi13122162.
The development of radio-frequency integrated circuits (RF-IC) necessitates higher requirements for the size of microtransformers. This paper describes millimeter-scale 3D transformers in millimeter-scale, solenoidal, and toroidal transformers manufactured using Micro-electromechanical Systems (MEMS). Two through-silicon via (TSV) copper coils with a high aspect ratio are precisely interleaved on a reserved air core (magnet core cavity) with a vertical height of over 1 mm because of the thickness of the substrate, which increases the performance while reducing the footprint. The effects of the wire width, coil turns, magnetic core, and substrate on the performance of the two transformers are discussed through numerical simulations. When an air core is present, solenoidal transformers are better than toroidal transformers in terms of performance and footprint; however, the gap decreases when the size is reduced. Additionally, the magnetic core significantly improves the performance of the toroidal transformer compared to that of the solenoid. Thus, the toroidal transformer has a higher potential for further size reduction. The two types of transformers were then manufactured completely using MEMS and electroplating. This paper discusses the influence of various parameters on millimeter-scale 3D transformers and realizes processing in silicon, which provides the foundation for integrating transformers in a chip.
射频集成电路（RF-IC）的发展对微型变压器的尺寸提出了更高要求。本文介绍了采用微机电系统（MEMS）制造的毫米级、螺线管式和环形变压器中的毫米级三维变压器。由于衬底的厚度，两个具有高纵横比的硅通孔（TSV）铜线圈精确地交错排列在一个垂直高度超过1毫米的预留空芯（磁芯腔）上，这在减小占地面积的同时提高了性能。通过数值模拟讨论了线宽、线圈匝数、磁芯和衬底对这两种变压器性能的影响。当存在空芯时，螺线管式变压器在性能和占地面积方面优于环形变压器；然而，当尺寸减小时差距会减小。此外，与螺线管相比，磁芯显著提高了环形变压器的性能。因此，环形变压器在进一步减小尺寸方面具有更高的潜力。然后完全使用MEMS和电镀工艺制造了这两种变压器。本文讨论了各种参数对毫米级三维变压器的影响，并实现了在硅中的加工，为在芯片中集成变压器奠定了基础。
