PROBLEM TO BE SOLVED: To provide a backing member having a novel structure capable of reliably forming resin containing a filler between reeds even when an arrangement pitch of the reeds is narrowed.SOLUTION: A backing member includes a resin layer 50 containing a filler 52, and a plurality of reeds 20 which are buried in the resin layer 50 and extend between an upper surface and a lower surface of the resin layer 50. Each of the reeds 20 includes a wiring part 24 and a terminal part 22 coupled to both ends of the wiring part 24. A width and a thickness of the wiring part 24 are respectively smaller than a width and a thickness of the terminal part 22. A distance between the wiring parts 24 of the reeds 20 adjacent to each other is set greater than a mean particle diameter of the filler 52.SELECTED DRAWING: Figure 15【課題】リードの配置ピッチが狭小化しても、リード間にフィラーを含有する樹脂を信頼性よく形成できる新規な構造のバッキング部材を提供する。【解決手段】フィラー５２を含有する樹脂層５０と、樹脂層５０の中に埋設され、樹脂層５０の上面から下面まで貫通する複数のリード２０とを含み、リード２０は、配線部２４と、配線部２４の両端に繋がる端子部２２とを備え、配線部２４の幅及び厚みは端子部２２の幅及び厚みよりも小さく、隣接するリード２０の配線部２４同士の間隔は、フィラー５２の平均粒径よりも広く設定される。【選択図】図１５
