Fabrication process for high-density wiring interposer using photosensitive multiblock copolyimide insulation layers for 3D packaging

We have developed a high-density wiring interposer for 10 Gbps signal propagation using a photosensitive polyimide. We optimized the basic properties of the photosensitive polyimide film and the lift-off process for the metal layer using an image-reversal-patterned negative photoresist for the fabrication of the interposer. We experimentally confirmed that the high-density wiring interposer could be fabricated using the polyimide and gold multilayered structure. Fine metal wiring was smoothly covered by the polyimide, as confirmed by scanning electron microscopy (SEM) of the cross section of the fabricated balance pair strip line structure.