WIRING BOARD

To provide a wiring board capable of suppressing generation of a solder bridge.SOLUTION: A wiring board 1 has one or more layers of wiring 3a, 3b and one or more layers of insulation layers 4a, 4b arranged on a first surface 2a side of a base material 2. The one or more layers of the wiring 3a, 3b have at least outermost wiring 13 located farthest from the base material 2. The one or more layers of the insulation layers 4a, 4b include at least an outermost insulation layer 14 that is arranged on a surface side opposite to a surface on the base material 2 side of the outermost wiring 13 and has opening units 5a, 5b positioned on the outermost wiring 13. The wiring board 1 further includes connection units 8 that are arranged in the opening units 5a, 5b of the outermost insulation layer 14 and are electrically connected to the outermost wiring 13. The outermost insulation layer 14 has a protrusion 15 on a surface opposite to a surface on the outermost wiring 13 side and on a peripheral edge of the opening units 5a, 5b. A height of the protrusion 15 of the outermost insulation layer 14 from the first surface 2a of the base material is higher than that of the connection unit 8 from the first surface 2a of the base material, and a pitch of the connection unit 8 is 50 μm or less.SELECTED DRAWING: Figure 1 【課題】はんだブリッジの発生を抑制することが可能な配線基板を提供する。【解決手段】基材２の第１面２ａ側に配置された１層以上の配線３ａ、３ｂ及び１層以上の絶縁層４ａ、４ｂを有する配線基板１であって、１層以上の配線３ａ、３ｂが、基材２から最も遠くに位置する最外配線１３を少なくとも有し、１層以上の絶縁層４ａ、４ｂが、最外配線１３の基材２側の面とは反対の面側に配置され、最外配線１３上に位置する開口部５ａ、５ｂを有する最外絶縁層１４を少なくとも有し、配線基板１が、最外絶縁層１４の開口部５ａ、５ｂに配置され、最外配線１３に電気的に接続された接続部８をさらに有し、最外絶縁層１４が、最外配線１３側の面とは反対の面、かつ、開口部５ａ、５ｂの周縁部に凸部１５を有し、最外絶縁層１４の凸部１５の基材の第１面２ａからの高さが、接続部８の基材の第１面２ａからの高さよりも高く、接続部８のピッチが、５０μｍ以下である。【選択図】図１