Focused atmospheric-pressure microsputterer for additive manufacturing of microelectronics interconnects

Abstract

The past decade has seen a new manufacturing revolution, in the form of additive manufacturing. While recent additive manufacturing processes can produce structural materials in intricate shapes not previously possible, additive manufacturing of functional materials remains a challenge. In particular, functional electronics must still be made via traditional lithographic and etching processes. This thesis introduces a microsputtering method to directly write metals with high resolution. A wire feed enables continuous, extended use of the system. We motivate, simulate, and test a novel electrostatic focusing system to improve the resolution of the imprints; this focusing scheme combines electrostatic and fluid effects to direct the sputtered material into a strip as narrow as 9 pm. The microstructure of the deposits, which affects their conductivity, is also explored and modified. Using gold as printable feedstock, this technology allows for smooth (55 nm roughness) deposits with ~65X the electrical conductivity of bulk metal.