Wiring board and method of manufacturing the same

摘要

A method of manufacturing a wiring board for use in mounting of an electronic component includes: forming an outermost wiring layer on a surface side where the electronic component is mounted; forming an insulating layer so as to cover the wiring layer; and forming a concave portion in the insulating layer. The concave portion is formed by removing, using a mask formed in a required shape by patterning, an exposed portion of the insulating layer in a step-like shape until a surface of a pad defined at a portion of the wiring layer is exposed. The concave portion is preferably formed by removing the portion of the insulating layer by sand blast.

主权项

1. A wiring board, comprising:
an outermost wiring layer which is formed on an insulating layer made of resin in the wiring board, extends outside of a mounting area for an electronic component, and includes a convex portion being formed thicker than the other portion of the outermost wiring layer in the mounting area for an electronic component and serving as a pad; a solder resist layer formed on a chip mounting surface and an external connection terminal bonding surface opposite to the chip mounting surface, which covers the outermost wiring layer and the insulating layer, is formed of a single layer and is different resin from the resin of the insulating layer; an electronic component mounted on the solder resist layer of the chip mounting surface; and an underfill resin filling the gap between the electronic component and the solder resist layer, wherein the solder resist layer of the chip mounting surface is thicker than that of the external connection terminal bonding surface, the solder resist layer of the chip mounting surface includes a concave portion which corresponds to the mounting area for mounting thereon the electronic component and to an area accommodating an underfill resin, the concave portion being formed in a larger size than a size of the electronic component and in a step-like shape, and has a flat bottom surface formed of the solder resist layer, wherein a top surface of the pad is exposed at the flat bottom surface of the concave portion to be flush with the flat bottom surface of the concave portion, and a side surface of the pad and the outermost wiring layer other than the top surface of the pad are covered with the solder resist layer, wherein the pad of the outermost wiring layer is formed of a portion of the wiring layer and a conductive layer which is made of the same metal as the wiring layer and the conductive layer is laminated on and integrated with the portion of the wiring layer, wherein the electronic component is placed inside the concave portion in a plain-view, and flip-chip bonded to the pad in the concave portion, wherein a height of the gap between the electronic component and the bottom surface of the concave portion is larger than a height of the step-shape portion which surrounding the concave portion, and wherein the underfill resin fill a gap between the electronic component and the bottom surface of the concave portion, and cover the area between outside of the electronic component and the step-shape portion surrounding the concave portion, and a part of the underfill resin is creeping up the side surface of the electronic component to form a fillet portion.