Wiring substrate, stacked wiring substrate, semiconductor device, and method for manufacturing wiring substrate

Abstract

This invention provides a wiring substrate, a stacked wiring substrate, a semiconductor device, and a method for manufacturing a wiring substrate. The wiring substrate 10 includes a first wiring structure 11 and a second wiring structure 12 formed on the first wiring structure 11, wherein the wiring density of the second wiring structure 12 is higher than that of the first wiring structure 11. The first wiring structure 11 includes a wiring layer 20, an insulating layer 21 covering the wiring layer 20, and a wiring layer 22 extending through the insulating layer 21 and electrically connected to the wiring layer 20. The second wiring structure 12 includes an insulating layer 30 formed on the insulating layer 21, a plurality of through-hole wirings 40 extending through the insulating layer 30, and a wiring layer 31 formed on the insulating layer 30 and electrically connected to the wiring layer 22 via the through-hole wirings 40. The filler content of the insulating layer 30 is lower than that of the insulating layer 21.