Fabrication and Optimization of High Aspect Ratio Through-Silicon-Vias Electroplating for 3D Inductor

Li, Haiwang; Liu, Jiasi; Xu, Tiantong; Xia, Jingchao; Tan, Xiao; Tao, Zhi

doi:10.3390/mi9100528

Cited by 16 publications

(13 citation statements)

References 23 publications

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“…Hollow Cu TSVs 45,163 , magnetic self-assembly for TSV fabrication 164 , void-free high-AR TSV filling 165,166 , magnetic core integration 59,106,163 .…”

Section: Powermentioning

confidence: 99%

MEMS inductor fabrication and emerging applications in power electronics and neurotechnologies

et al. 2021

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MEMS inductors are used in a wide range of applications in micro- and nanotechnology, including RF MEMS, sensors, power electronics, and Bio-MEMS. Fabrication technologies set the boundary conditions for inductor design and their electrical and mechanical performance. This review provides a comprehensive overview of state-of-the-art MEMS technologies for inductor fabrication, presents recent advances in 3D additive fabrication technologies, and discusses the challenges and opportunities of MEMS inductors for two emerging applications, namely, integrated power electronics and neurotechnologies. Among the four top-down MEMS fabrication approaches, 3D surface micromachining and through-substrate-via (TSV) fabrication technology have been intensively studied to fabricate 3D inductors such as solenoid and toroid in-substrate TSV inductors. While 3D inductors are preferred for their high-quality factor, high power density, and low parasitic capacitance, in-substrate TSV inductors offer an additional unique advantage for 3D system integration and efficient thermal dissipation. These features make in-substrate TSV inductors promising to achieve the ultimate goal of monolithically integrated power converters. From another perspective, 3D bottom-up additive techniques such as ice lithography have great potential for fabricating inductors with geometries and specifications that are very challenging to achieve with established MEMS technologies. Finally, we discuss inspiring and emerging research opportunities for MEMS inductors.

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“…Hollow Cu TSVs 45,163 , magnetic self-assembly for TSV fabrication 164 , void-free high-AR TSV filling 165,166 , magnetic core integration 59,106,163 .…”

Section: Powermentioning

confidence: 99%

MEMS inductor fabrication and emerging applications in power electronics and neurotechnologies

et al. 2021

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“…Through-silicon via (TSV) is a key structure of 3D integrated circuits (IC) [1][2][3][4][5]. TSVbased 3D ICs have a shorter interconnect length, higher integration density, faster data communication, and lower power consumption [6][7][8][9][10]. Due to the excellent anti-noise characteristic during the transmission of different signals, shielded differential throughsilicon vias (SDTSV) have wide prospects in 3D ICs [11].…”

Section: Introductionmentioning

confidence: 99%

An Anisotropic Equivalent Thermal Model for Shield Differential Through-Silicon Vias

Shan

Chen

et al. 2021

Micromachines

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An accurate equivalent thermal model is proposed to calculate the equivalent thermal conductivity (ETC) of shield differential through-silicon via (SDTSV). The mathematical expressions of ETC in both horizontal and vertical directions are deduced by considering the anisotropy of SDTSV. The accuracy of the proposed model is verified by the finite element method (FEM), and the average errors of temperature along the X-axis, Y-axis, diagonal line, and vertical directions are 1.37%, 3.42%, 1.76%, and 0.40%, respectively. Compared with COMSOL, the proposed model greatly improves the computational efficiency. Moreover, the effects of different parameters on the thermal distribution of SDTSV are also investigated. The thermal conductivity is decreased with the increase in thickness of SiO2. With the increase in pitch, the maximum temperature of SDTSV increases very slowly when β = 0°, and decreases very slowly when β = 90°. The proposed model can be used to accurately and quickly describe the thermal distribution of SDTSV, which has a great prospect in the design of 3D IC.

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“…To extend research on micromotor coils with magnetic materials, we focus on high aspect ratio 3D solenoid coils with silicon steel cores. In a previous study, we investigated the electroplating process of high aspect ratio through silicon vias (TSVs) and then fabricated both air-core and iron-core 3D solenoid MEMS coils [23], [24].…”

Section: Introductionmentioning

confidence: 99%

A Radial-flux Permanent Magnet Micromotor with 3D Solenoid Iron-core MEMS In-chip Coils of High Aspect Ratio

Tao

Sun

et al. 2020

IEEE Electron Device Lett.

Self Cite

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Because of the difficulty in fabricating iron-core solenoid coils by micro electro-mechanical system (MEMS) processes, existing micromotors typically have an axial-flux structure with planar spiral coils or air-core solenoid coils. However, solenoid iron-core microcoils have a higher inductance and a lower magnetic resistivity than spiral coils and air-core solenoid coils. In this study, a radialflux permanent magnet (PM) micromotor with 3D iron-core MEMS in-chip coils of high aspect ratio was designed and fabricated. The three-phase PM brushless direct current (BLDC) micromotor has four Nd-Fe-B magnet poles on a steel rotor and six solenoid Cu coils of high aspect ratio (coil height/line width = 14) in the silicon stator fabricated using MEMS processes. Iron cores were inserted into the coils, and a low-resistivity magnetic circuit was established. At 100 Hz, the inductance of a 15-turn coil was 13.2µH. The coils were embedded tightly in the silicon substrate, resulting in a good heat dissipation performance and thus a high current-carrying capacity. The hexagonal sheet-type micromotor weighed 2.25 g with a volume of 586.5 mm 3 before bearing packaging. The modeling results showed that at 10000 rpm, the torque was 676µN•m and the power density was 314 W/kg. This micromotor incorporates a conventional large-scale BLDC motor structure and the proposed design will help improve the power density and efficiency of micromotors, thereby broadening their application prospects. Index Terms-Iron-core microcoils, micromotors, permanent magnet motors, power MEMS.

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Fabrication and Optimization of High Aspect Ratio Through-Silicon-Vias Electroplating for 3D Inductor

Cited by 16 publications

References 23 publications

MEMS inductor fabrication and emerging applications in power electronics and neurotechnologies

MEMS inductor fabrication and emerging applications in power electronics and neurotechnologies

An Anisotropic Equivalent Thermal Model for Shield Differential Through-Silicon Vias

A Radial-flux Permanent Magnet Micromotor with 3D Solenoid Iron-core MEMS In-chip Coils of High Aspect Ratio

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