Conductive ink for filling vias

摘要

Vias (holes) are formed in a wafer or a dielectric layer. A low viscosity conductive ink, containing microscopic metal particles, is deposited over the top surface of the wafer to cover the vias. An external force is applied to urge the ink into the vias, including an electrical force, a magnetic force, a centrifugal force, a vacuum, or a suction force for outgassing the air in the vias. Any remaining ink on the surface is removed by a squeegee, spinning, an air knife, or removal of an underlying photoresist layer. The ink in the vias is heated to evaporate the liquid and sinter the remaining metal particles to form a conductive path in the vias. The resulting wafer may be bonded to one or more other wafers and singulated to form a 3-D module.

主权项

1. An electrical structure comprising:
a hole through a first layer forming part of the electrical structure, the hole being formed between a first surface and an opposite second surface of the first layer; sintered metal particles within the hole forming a conductive path between the first surface and the second surface, the sintered metal particles remaining from a conductive ink that was deposited over the first surface and heated to sinter the metal particles, the metal particles having diameters including greater than 1 micron, the sintered metal particles forming a conductive via extending between the first surface and the second surface; a first electrical connection made to a top of the via at the first surface; and a second electrical connection made to a bottom of the via at the second surface.