Wiring board

A wiring board comprising:

• a first interconnect structure including an insulating layer, and a first interconnect layer and a first insulating layer that are disposed on and in contact with an upper surface of the insulating layer;
• and
• a second interconnect structure, including a second interconnect layer and a second insulating layer, and disposed on the first interconnect structure, wherein:
• the first interconnect layer includes a first via interconnect embedded in the insulating layer, and a first interconnect pattern connected to the first via interconnect and disposed on and in contact with the upper surface of the insulating layer,
• the first via interconnect has an inverted truncated cone shape with a diameter that gradually decreases downward toward a lower surface of the insulating layer,
• an interconnect width and an interconnect spacing of the second interconnect layer are respectively smaller than an interconnect width and an interconnect spacing of the first interconnect layer,
• the first insulating layer covers the upper surface of the insulating layer and a side surface of the first interconnect layer, and exposes an upper surface of the first interconnect layer,
• the second insulating layer covers the upper surface of the first interconnect layer and an upper surface of the first insulating layer,
• the first insulating layer and the second insulating layer include a filler,
• an average grain diameter and a maximum grain diameter of the filler included in the second insulating layer are respectively smaller than an average grain diameter and a maximum grain diameter of the filler included in the first insulating layer, and
• a roughness of the upper surface of the first insulating layer is smaller than a roughness of the upper surface of the insulating layer.

A wiring board comprising:

• a first interconnect structure including an insulating layer, and a first interconnect layer and a first insulating layer that are disposed on and in contact with an upper surface of the insulating layer;
• and
• a second interconnect structure, including a second interconnect layer and a second insulating layer, and disposed on the first interconnect structure, wherein:
• the first interconnect layer includes a first via interconnect embedded in the insulating layer, and a first interconnect pattern connected to the first via interconnect and disposed on and in contact with the upper surface of the insulating layer,
• the first via interconnect has an inverted truncated cone shape with a diameter that gradually decreases downward toward a lower surface of the insulating layer,
• an interconnect width and an interconnect spacing of the second interconnect layer are respectively smaller than an interconnect width and an interconnect spacing of the first interconnect layer,
• the first insulating layer covers the upper surface of the insulating layer and a side surface of the first interconnect layer, and exposes an upper surface of the first interconnect layer,
• the second insulating layer covers the upper surface of the first interconnect layer and an upper surface of the first insulating layer,
• the first insulating layer and the second insulating layer include a filler,
• an average grain diameter and a maximum grain diameter of the filler included in the second insulating layer are respectively smaller than an average grain diameter and a maximum grain diameter of the filler included in the first insulating layer, and
• the first insulating layer has a thickness identical to a thickness of the interconnect pattern of the first interconnect layer.