| AVS 64th International Symposium & Exhibition | |
| Manufacturing Science and Technology Group | Thursday Sessions |
| Session MS-ThM |
| Session: | Additive and Other Novel Manufacturing Techniques |
| Presenter: | Yosef Kornbluth, Massachusetts Institute of Technology |
| Authors: | Y. Kornbluth, Massachusetts Institute of Technology R. Matthews, MIT Lincoln Laboratory L. Parameswaran, MIT Lincoln Laboratory L. Racz, MIT Lincoln Laboratory L. Velásquez-García, Massachusetts Institute of Technology |
| Correspondent: | Click to Email |
Additive manufacturing technologies promise to transform the development and production of agile microsystems, but are limited by the ability to print microelectronics-quality interconnects. State of the art 3D printing techniques for conductors cannot yet deliver the feature resolution and electrical conductivity required for high performance microcircuits, and have materials and substrate constraints and post-processing requirements. We develop a novel microplasma sputtering system that has the potential to provide direct-write capability of quality metal interconnects on non-standard substrates for integrated circuits, with future extensibility to dielectrics and semiconductors. The microplasma is generated at atmospheric pressure, obviating the need for a vacuum. By manipulating the metal at the atomic level, we retain the resistivity of bulk metal, and by sputtering the metal, we eliminate the need for post-processing or lithographic patterning.
We have modeled and constructed a first-generation system that incorporates continuous material feed and focusing with electrostatic fields. The microplasma head has a grounded central target wire, surrounded by two pairs of electrodes evenly distributed around the target: two opposing electrodes biased at a positive voltage to form the plasma, and two biased at a negative voltage to focus the plasma. Electrostatic fields guide the ionized fraction of the working gas towards a localized spot on the substrate. The directed ions collide with other gas atoms and, crucially, with sputtered metal atoms from the target. The net force of these collisions drags the metal atoms towards the substrate. This indirect electrostatic focusing mitigates the inherent spread of the sputtered material caused by collisions at atmospheric pressure, and enables fine feature definition. By focusing the sputtered material, we achieve imprints significantly narrower than the cathode, avoiding the need to machine target electrodes as small as the desired feature size.
Multi-physics COMSOL simulations predict that features orders of magnitude narrower than the target-wire cross section can be printed if the electric fields are set appropriately. We present findings from our COMSOL simulations and experimental confirmation of key findings.
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This material is based upon work supported under Air Force Contract No. FA8721-05-C-0002 and/or FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. Air Force.