Three-dimensional microstructure technology for microfluidic systems and integrated inductors

Abstract

In this dissertation, three-dimensional microstructure technology for microfluidic systems and integrated inductors has been studied. Several key micromachining techniques, which provide essentials in three-dimensional microstructure fabrication, are developed in order to overcome process limits in the current planar integrated circuit (IC) technology and enlighten the IC technology to take advantage of various three-dimensional microstructures with integrated circuits. These techniques have been utilized to improve the state-of-the-art of several application fields. First, three-dimensional lithography with conventional tools and materials has been developed to fabricate three-dimensional solenoid integrated inductors, which could not be easily fabricated by the current IC technology in spite of their superior device performance. The fabricated monolithic solenoid inductors have shown quality (Q) factors of over 20 at GHz frequencies with inductance of several nH. The three-dimensional lithography has also been used to fabricate three-dimensional single-body microfluidic components. An ink drop of 10microns in the printed diameter has been successfully ejected from the fabricated three-dimensional orifice plate assembly, which indicates an unprecedented printing resolution of 2400dpi (dots per inch). Second, another three-dimensional technique has been devised, which truly integrates real three-dimensional metallic microstructures. Based on this method, a new concept of "On-Circuit Passives" has been developed. In this concept, passive electrical components are integrated over a standard integrated circuit. Thus, the passive elements do not need additional area and the electrical performance is enhanced due to the monolithic feature and the minimized parasitic effects to the substrate. This concept has been verified by the levitated inductors, which are levitated by several tens of microns right on the substrate. The fabricated levitated inductors have shown...