Formation of a through-electrode by inkjet deposition of resin pastes
View Patent ↗When forming a resin material in a through hole, an electrode pad is formed in the bottom portion of the through hole, an insulating material is formed about the periphery of the through hole and a conductive material is formed in the central portion by an inkjet method, inkjet-ejected resins being ejected in such a manner that concavo-convex indentations and projections are formed in the surface thereof, whereby the adhesiveness between the insulating material and the conductive material and the adhesiveness between the insulating material and the inner walls of the through hole can be improved. Therefore, it is possible to suppress mechanical defects such as detachment of conductive material at the interfaces between the inner surface of the through hole and the resin or conductor layer, or electrical defects such as insulation defects, conduction defects, or the like.
1. A method of forming a through-electrode for electrically connecting an electrode of a semiconductor element on a front surface of a substrate to an electrode pad on a rear surface of the substrate,
the method comprising:
forming a through hole in the substrate above the electrode pad;
forming by inkjet deposition a layer of an insulating resin paste, around an inner circumference of the through hole leaving a space in a central portion of the through hole;
filling by inkjet deposition the space with a layer of one or a plurality of conductive resin pastes; and
forming laminated layers by successively repeating the step of forming the layer of insulating resin paste and the step of filling the space with the layer of the one or the plurality of conductive resin pastes until the insulating resin paste and the one or a plurality of conductive resin pastes filled into the through hole reach the front surface of the substrate,
wherein after forming insulating resin and conductive resin, an interface between the insulating resin and the conductive resin includes concavo-convex indentations and projections.
2. The method of forming the through-electrode according to claim 1 , wherein, after forming the laminated layers, a first thickness of the insulating resin in a direction along a diameter of the through hole near the top of the through hole is larger than a second thickness in a direction along the diameter of the through hole near the axial middle of the through hole.
3. The method of forming the through-electrode according to claim 1 , wherein, after forming the laminated layers, a first thickness of the insulating resin in a direction along a diameter of the through hole near the top of the through hole is smaller than a second thickness in a direction along the diameter of the through hole near the axial middle of the through hole.
4. The method of forming the through-electrode according to claim 1 , wherein after forming the laminated layers, a thickness of the insulating resins in a direction along diameters of the through hole is alternately larger and smaller along the axial length of the through hole.
5. The method of forming the through-electrode according to claim 1 , wherein after forming the laminated layers, the diameter of the is continuously smaller from the front surface side of the substrate toward the rear surface side of the substrate.
6. The method of forming the through-electrode according to claim 1 , wherein the conductive resin paste comprises gold (Au), copper (Cu) or silver (Ag).
7. The method of forming the through-electrode according to claim 1 , wherein depositing positions are staggered between layers during the deposition of the insulating resin paste and the conductive resin paste.
8. The method of forming the through-electrode according to claim 1 , wherein the deposition volume of resin paste is varied between layers during the deposition of insulating resin paste and conductive resin paste.