3-D construction of monolithic passive components for RF and microwave ICs using thick-metal surface micromachining technology

Abstract

As a viable technological option to address today's strong demands for high-performance monolithic low-cost passive components in RF and microwave integrated circuits (ICs), a new CMOS-compatible versatile thick-metal surface micromachining technology has been developed. This technology enables to build arbitrary three-dimensional (3-D) metal microstructures on standard silicon substrate as post-IC processes at low temperature below 120 C. Using this technology, various highly suspended 3-D microstructures have been successfully demonstrated for RF and microwave IC applications. We have demonstrated spiral inductors suspended 100 m over the substrate, coplanar waveguides suspended 50 m over the substrate, and complicated microcoaxial lines, which have 50m-suspended center signal lines surrounded by inclined ground shields of 100 m in height. The microwave performance of the microcoaxial transmission line fabricated on a glass substrate has been evaluated to achieve very low attenuation of 0.03 dB/mm at 10 GHz with an effective dielectric constant of 1.6. The process variation/manufacturability, mechanical stability, and package issues also have been discussed in detail. Index Terms-Coaxial transmission lines, coplanar microstrip lines, high-, inductors, RF and microwave microelectromechanical systems (MEMS), silicon RF integrated circuits (ICs), surface micromachining, three-dimensional (3-D) micromachined passive components.

Stretchable copper interconnects with three-dimensional coiled structures

“…Although many previous works have also demonstrated the fabrication of similar 3D metal coil structures by electroplating techniques successfully, they mainly focused on conventional applications as solenoid-type integrated inductors for achieving higher RF performance [26][27][28]. For characterizing the capability as stretchable interconnects, we transferred the 3D coil electrodes onto an elastomeric PDMS substrate.…”

“…On the other hand, the construction of 3D metal coils by surface micromachining techniques has been a key technology in the production of high-performance solenoid inductors for radio-frequency (RF) and microwave integrated circuits (ICs) [26][27][28]. In contrast to 2D spiral or meander-type inductors fabricated by conventional planar technology [29,30], the 3D solenoid inductor can provide many advantages such as smaller size and parasitic capacitance, as well as higher inductance and quality factor [26][27][28]. Although various approaches have been investigated for the fabrication of 3D solenoid structures on a rigid IC chip, there has been no attempt to apply them as stretchable interconnects within an elastomeric matrix.…”

On-chip concentration of bacteria using a 3D dielectrophoretic chip and subsequent laser-based DNA extraction in the same chip

“…For 3D DEP chips, an additional SiO 2 passivation layer (5000 Å) was deposited by PECVD (STS 310PC, UK). Then, the 70 μm thick positive photoresist (AZ 9260, Clariant Ltd, USA) pattern was formed on the SiO 2 passivation layer as a SiO 2 etch mask and mold for self-aligned 3D DEP trap electrodes electroplating [37,38]. The SiO 2 layer was etched by buffered oxide etch (BOE, JT Backer R ), and Ni plating is done until the photoresist mold was filled to reach a 50 μm thickness.…”

Investigation of electrical and magnetic properties of ferro-nanofluid on transformers

“…Transformer losses become dramatic at high frequencies and limit the performance of the transformers. Previous studies have discussed in detail the causes of transformer losses such as parasitic capacitance, ohmic loss, and substrate loss [15-18]. Core loss from the solid magnetic core significantly affected the performance of the transformers.…”