Multi-layer fabrication in integrated circuit systems

Abstract

A method for fabricating layers permits the accurate removal of surface material in a multi-layer multi-chip carrier. An intermediate layer of solid vias is deposited over a circuit layer attached to a substrate. The layer can be filled with a dielectric material. The substrate is attached to a substrate holder such that the intermediate layer is exposed, and the substrate holder is placed onto a rotating platen polisher with the intermediate layer facing the platen surface. Tooling presses the intermediate layer against the rotating polishing platen, allowing the substrate holder and substrate to rotate with three degrees of angular freedom, letting the substrate and intermediate layer self-align to the polishing platen in order to uniformly remove material from the intermediate layer surface. A second circuit layer can be formed on the resulting structure. The foregoing steps can be iterated to build a multi-layer structure of circuit layers separated by uniformly thick dielectric and via layers. As an alternative method, substrate attached to a substrate holder is placed against the platen surface of a shaking polisher, allowing the substrate and substrate holder to self-align to the polishing platen. In a third embodiment, where metal irregularities exist along the intermediate layer surface, wiping the surface evenly with cloth soaked in an appropriate etchant can uniformly remove the unwanted metal irregularities.