CMOS compatible electrochemical process for improving quality factor of spiral microinductors

Fabrication and analytical evaluation of three-dimensional microsolenoids achieved in fused silica by femtosecond-laser-based microsolidifying process

“…These methods have limitations to the precise calculation or prediction of the properties of microscale solenoids owing to their lack of considering the unique geometry configurations of 3D microsolenoids, such as a greater ratio of helix pitch to radius etc. However, the reported 3D microsolenoids, which have been applied in on-chip nuclear magnetic resonance (NMR) and other microsystems [1][2][3][4][5], mostly consist of a sparse structure with a large ratio of helix pitch to coil radius; and the influence of the wire diameter cannot be neglected.With the development of femtosecond laser technology, a femtosecond laser irradiation followed by chemical etching (FLICE) technology has been utilised to fabricate complex 3D microchannels in fused silica [13][14][15][16]. In this Letter, a femtosecond-laser-based microsolidifying process is proposed to fabricate 3D cylindrical microsolenoids by combining the FLICE technology and liquid-metalinjection technology.…”

“…Introduction: Three-dimensional (3D) microsolenoids have always been critical for miniaturisation of large-scale functional systems, including integrated circuits (ICs), microfluidic systems and microelectromechanical systems (MEMS) [1][2][3][4][5]. Although many efforts have been directed towards 3D microfabrication, it is still a technical challenge to achieve complex 3D microsolenoids [4][5][6][7].…”

“…These methods have limitations to the precise calculation or prediction of the properties of microscale solenoids owing to their lack of considering the unique geometry configurations of 3D microsolenoids, such as a greater ratio of helix pitch to radius etc. However, the reported 3D microsolenoids, which have been applied in on-chip nuclear magnetic resonance (NMR) and other microsystems [1][2][3][4][5], mostly consist of a sparse structure with a large ratio of helix pitch to coil radius; and the influence of the wire diameter cannot be neglected.…”