WIRING BOARD

PROBLEM TO BE SOLVED: To provide a wiring board on which a via conductor can be formed in a narrow frame body while ensuring a wide mounting region of an electronic component.SOLUTION: A wiring board 100 comprises: a rectangular insulating substrate 11 in plan view; a rectangular frame body 12 on which forms a cavity for housing an electronic component; a via hole 12B which is formed at the corner of the frame body 12 and pierces the frame body 12 in a thickness direction and has a diameter equal to or less than 100 μm; a via conductor 13 which is filled in the via hole 12B and which is not exposed on an internal surface of the frame body 12; and a metalization layer 14 for encapsulation, which is formed on a top face of the frame body 12 and electrically connected with the via conductor 13. The corner of the frame body 12 forms a wide part 12A which expands toward a mounting region R in plan view and a width of the frame part 12 other than the corner is equal to or less than 150 μm. The internal surface 12C of the wide part 12A has a linear shape in plan view, and an angle α formed between the internal surface 12C and an internal surface 12D adjacent to the internal surface 12C is an obtuse angle.SELECTED DRAWING: Figure 1 【課題】電子部品の搭載領域を広く確保しつつ幅の狭い枠体にビア導体を形成できる配線基板を提供する。【解決手段】配線基板１００は、平面視矩形の絶縁性基板１１と、電子部品を収容するための凹部を形成する矩形状の枠体１２と、枠体１２のコーナー部に形成され、枠体１２を厚み方向に貫通する直径が１００μｍ以下のビアホール１２Ｂと、ビアホール１２Ｂ内に充填され、枠体１２の内壁面から露出していないビア導体１３と、枠体１２の上面に形成され、ビア導体１３と電気的に接続された封止用のメタライズ層１４とを備える。枠体１２は、平面視において、コーナー部が搭載領域Ｒに向かって広がった幅広部１２Ａとなっており、コーナー部以外の幅が１５０μｍ以下である。幅広部１２Ａは、平面視において、内壁面１２Ｃが直線形状であり、内壁面１２Ｃ及び内壁面１２Ｃに隣接する内壁面１２Ｄの間で形成される角度αが鈍角である。【選択図】図１