Method for the fabrication of a device comprising electrical through hole interconnects, comprising the steps of: A) providing a substrate, typically covered by an oxide layer and comprising an open contact, B) bonding a silicon die to said substrate, whereby an internal contact is created by flipping said silicon die with a metal pad on its upper surface, said metal pad being covered with an oxide layer, said, internal contact being isolated by a first layer of a first dielectric material, C) thinning said bonded silicon die without revealing said internal contact, D) dry etching said silicon die, forming at least one substrate hole, until said first layer of said first dielectric material in said internal contact is reached, E) dry etching said first layer of said first dielectric material at the bottom of said substrate hole, F) depositing a second layer of a second dielectric material, said substrate hole thereby being filled, G) depositing and patterning a thin metal hard-mask layer, and dry etching in said second layer of said second dielectric material within said substrate hole in said silicon die, forming a dielectric hole within said substrate hole, whereby the sidewalls of said substrate hole remain covered with said second layer of said second dielectric material, until the bottom of said substrate hole is reached, H) depositing a thick metal layer, creating an interconnect between said open contact and said internal contact, thereby transforming said dielectric hole into a conductor hole, and etching said thick metal layer, I) depositing a third layer of a third dielectric material, thereby filling said conductor hole. A) providing a substrate, typically covered by an oxide layer and comprising an open contact, B) bonding a silicon die to said substrate, whereby an internal contact is created by flipping said silicon die with a metal pad on its upper surface, said metal pad being covered with an oxide layer, said, internal contact being isolated by a first layer of a first dielectric material, C) thinning said bonded silicon die without revealing said internal contact, D) dry etching said silicon die, forming at least one substrate hole, until said first layer of said first dielectric material in said internal contact is reached, E) dry etching said first layer of said first dielectric material at the bottom of said substrate hole, F) depositing a second layer of a second dielectric material, said substrate hole thereby being filled, G) depositing and patterning a thin metal hard-mask layer, and dry etching in said second layer of said second dielectric material within said substrate hole in said silicon die, forming a dielectric hole within said substrate hole, whereby the sidewalls of said substrate hole remain covered with said second layer of said second dielectric material, until the bottom of said substrate hole is reached, H) depositing a thick metal layer, creating an interconnect between said open contact and said internal contact, thereby transforming said dielectric hole into a conductor hole, and etching said thick metal layer, I) depositing a third layer of a third dielectric material, thereby filling said conductor hole.