Micron scale conductors and integrated passives in LTCC's by electrophoretic deposition

Electrophoretic deposition (EPD) is a low cost, particle based, electrodynamic forming process suitable for particles in the micron to nanometer size range. It can be used to reproduce patterns of conductor or dielectric material with micron scale resolution. This can be applied to the miniaturization of interconnects and components incorporated into low temperature co-fired ceramic modules. The process for forming these patterns is as follows. First, a conductive pattern is imaged by conventional photolithography on a plastic film. This pattern can then be coated with particles by EPD. Using a binder, this deposited particulate pattern can be transferred to another surface, where it can be sintered or fused to make continuous conductor lines, dielectric patches or layers with micron scale vias. The photolithographically produced conductor pattern can then be re-used repeatedly to create more patterned particulate depositions. In this manner a single pattern produced by photolithography can be used to make multiple parts with photolithographic scale resolution. Using this process we have created 5 μmwide silver conductor lines on a 10 μm spacing, layers with 5 μmdiameter vias, and 600 nm thick barium titanate dielectric layers.