Metallurgy Division researchers have developed a new process that could make possible whole new classes of sensors and microelectromechanical (MEMS) devices. This advance is based on the introduction of a novel superconformal electrodeposition process that allows ferromagnetic material to be easily integrated into existing industrial process streams used to produce state-of-the-art microelectronics.
The new process allows the void-free filling of high aspect ratio nanoscale, lithographically patterned structures, such as vias and trenches, with technically relevant magnetic alloys. This capability will enable the exploration of new complex heterogeneous 3-D MEMS architectures that combine magnetic alloys with non-magnetic metallizations such as on-chip copper interconnects.
These innovations are an outgrowth of measurements and models under development in MML to allow quantitative design and controlled fabrication of nanoscale, magnetically active structures such as inductors and actuators. Preliminary measurements reveal that optimal filling with the magnetic alloys is associated with the presence of hysteresis during current-voltage deposition cycles on planar substrates, providing an easy measurement method to determine if creation of quality nanoscale structures is possible for a given electrolyte. Good feature filling with the magnetic alloys also appears to be tied to significant electrolyte resistance, such that complete filling of sub-micrometer features with only minimal deposition on the neighboring free surface is possible.
It is anticipated that the new measurements and models will facilitate rapid and easy industrial adoption of these methods to create new classes of MEMS and sensor devices with previously unavailable capabilities.