High aspect ratio microsystem fabrication by ion track lithography

Sammanfattning: The microsystem processing of today is based on an assortment of diverse and contrasting fabrication techniques, sprung from the microelectronic industry. Microsystem technology has primarily been developed to meet the demands for scaled down low-cost sensor and actuator systems. These devices are based on a number of contrasting principles, e.g. capacitance of mechanical membranes, microfluidic or piezoelectric actuation, electrostatic or heat deflection, etc. Clearly the disparate designs of these devices require microfabrication processes that are flexible and unrestricted, allowing deep and vertical structures to be obtained.The scope of this thesis is microstructuring and microsystem fabrication of primarily polymer materials by means of ion track lithography. Ion track lithography in combination with microstructuring unwraps unique and untouched grounds. The available building blocks in these microsystems include high aspect ratio (depth-to-width ratio) capillaries and metal wires of nanometric width, deep vertical cavities as well as conventional double-sided thin film lithographic patterns. The blocks have been combined to materialise a few technology demonstrators integrated in flexible polyimide foils and laminates, commercially attractive materials with excellent mechanical, temperature, and high frequency electronic properties. A magnetic field sensing structure based on the magnetoresistance as well as inductor coils for microwave circuitry have been fabricated and characterised. The various fabrication processes have been evaluated with respect to resolution, aspect ratio, and verticality.We can present a deep vertical micro? and nanofabrication technique, overriding the natural anisotropy or isotropy of many of the diverse materials employed in the microsystem field. We have obtained pores, capillaries with aspect ratios of up to 400, clusters of electrodeposited magnetic and non-magnetic nanowires with similar aspect ratio, solid complex structures with close to vertical walls as well as through hole microvias in flexible printed circuitboards.