Patent ID: 8866027

Claim:
A printed wiring board that is a substrate for a suspension in a hard disk drive, the printed wiring board comprising: a metallic substrate; an insulating layer provided on a surface of the metallic substrate; a conductive layer provided on a surface of the insulating layer, the conductive layer being electrically connected to the metallic substrate; a via hole formed in the insulating layer and the conductive layer, wherein the via hole has a bottom in the metallic substrate, and has a wall surface in the insulating layer and in the conductive layer; and a conductive paste that fills the via hole to electrically connect the metallic substrate and the conductive layer to each other, wherein the conductive layer includes a conductive film formed on the surface of the insulating layer, wherein the metallic substrate is made of stainless steel, and the conductive paste is composed of an epoxy resin of bisphenol A, butyl carbitol acetate and imidazole latent hardener and silver particles, wherein the printed wiring board has been subjected to a process in which electrical current is applied to an interface between the metallic substrate and the conductive paste, the contact resistance at the interface between the metallic substrate and the conductive paste is 0.03 Ω·mm 2 or less, wherein the via hole has a first portion formed in the insulating layer and a second portion formed in the conductive layer, the second portion being stacked on the first portion along an axis direction of the via hole, wherein the conductive paste is in contact with the insulating layer within the via hole, and the length of a part at which the silver particles are anchored to the metallic substrate is 0.1 μm or longer and 0.6 μm or shorter.