Patent ID: 8141245
Filing Date: 2012-03-27
Classification: H01L,H05K,Y10T

Abstract:
1. A method of forming a circuit board comprising: (a) providing an electrically conductive sheet having a through-hole or via therethrough; (b) conformally coating the electrically conductive sheet, including an interior surface of the through-hole, with an insulating material, wherein an interior surface of the insulating material in the through-hole converges from a position adjacent the one side of the conformally coated electrically conductive sheet to a position intermediate the one side and the other side of the conformally coated electrically conductive sheet, and diverges from the position intermediate the one side and the other side of the conformally coated electrically conductive sheet to a position adjacent the other side of the conformally coated electrically conductive sheet; (c) forming a first plurality of conductors on one side of the conformally coated electrically conductive sheet; (d) forming a second plurality of conductors on the other side of the conformally coated electrically conductive sheet; and (e) forming a plurality of through-hole conductors on the insulating material in the through-hole by depositing a photoresist on a conductor layer deposited in the through-hole, patterning the photoresist, and removing unhardened portions of the photoresist and portions of the conductor layer under the unhardened portions of the photoresist, wherein each through-hole conductor is electrically isolated from each other through-hole conductor and each through-hole conductor is electrically connected to at least one conductor on the one side of the conformally coated electrically conductive sheet and at least one conductor on the other side of the conformally coated electrically conductive sheet.