Method for manufacturing wiring structure

A method for manufacturing a wiring structure, the method comprising:

• preparing a substrate including a main surface where a first concave portion and a second concave portion are formed, the first concave portion including a first bottom surface and a first wall surface, the second concave portion including a second bottom surface and a second wall surface, and a minimum width of the first bottom surface being larger than a minimum width of the second bottom surface;
• forming a temporary protective layer on the main surface of the substrate, the temporary protective layer having a pattern including an opening through which at least a part of the first bottom surface is exposed, and comprising a portion blocking the second concave portion;
• forming a first metal plating layer on the first bottom surface exposed in the opening;
• removing the temporary protective layer to expose the second concave portion;
• forming a second metal plating layer comprising a portion filing the second concave portion and a portion provided on the first metal plating layer, thereby forming a conductor layer comprising the first metal plating layer and the second metal plating layer;
• and
• removing a part of the conductor layer, thereby forming a first conductor portion provided in the first concave portion and comprising the first metal plating layer and the second metal plating layer, and a second conductor portion provided in the second concave portion and comprising the second metal plating layer, wherein
• the substrate comprises a seed layer having a surface including the first bottom surface and the second bottom surface, and
• the first metal plating layer and the second metal plating layer are formed by electrolytic plating.