Multilayer wiring substrate, probe card, and method for manufacturing multilayer wiring substrate

A multilayer wiring substrate comprising:

• a substrate main body including a first main surface and a second main surface;
• and
• a plurality of wiring lines provided in the substrate main body, the plurality of wiring lines extending from the first main surface toward the second main surface side;
• wherein
• the substrate main body includes a plurality of insulator layers laminated on top of one another;
• the plurality of wiring lines each include via conductors separately provided in the plurality of insulator layers;
• and
• in at least one of the plurality of wiring lines, a diameter of the via conductor provided in a first insulator layer defining the first main surface of the substrate main body is smaller than a diameter of the via conductor provided in at least one of the plurality of insulator layers other than the first insulator layer.

A multilayer wiring substrate comprising:

• a substrate main body including a first main surface and a second main surface;
• and
• a plurality of wiring lines provided in the substrate main body, the plurality of wiring lines extending from the first main surface toward the second main surface side;
• wherein
• in the first main surface, a recess portion is provided between adjacent ones of the plurality of wiring lines.