Circuit board

1 . A circuit board comprising:

an insulating layer; and

an electrode part disposed in the insulating layer,

wherein the insulating layer includes:

a plurality of first grooves provided on an upper surface of the insulating layer and spaced apart in a horizontal direction; and

a through hole overlapping at least one of the plurality of first grooves in a vertical direction,

wherein the electrode part includes:

a first circuit pattern disposed in the plurality of first grooves; and

a through electrode disposed in the through hole,

wherein the insulating layer includes a resin and a plurality of fillers disposed in the resin,

wherein the plurality of fillers include a plurality of embedded fillers embedded in the resin, and a plurality of first exposed fillers exposed through the through hole and in contact with the through electrode,

wherein an inner wall of the through hole of the insulating layer includes a first portion formed of the resin and etched by plasma treatment, and a second portion formed of the plurality of first exposed fillers and etched by the plasma treatment together with the first portion,

wherein the through electrode is in contact with the first portion and the second portion, and

wherein the first portion and the second portion have a surface roughness in a range of 0.5 μm to 1.0 μm.

2 . The circuit board of claim 1 , wherein the first portion and the second portion have a serrated shape.

3 . The circuit board of claim 1 , wherein the plurality of fillers include a plurality of second exposed fillers exposed through the plurality of first grooves and in contact with the first circuit pattern,

wherein an inner wall of the first grooves of the insulating layer includes a third portion formed of the resin and etched by plasma treatment, and a fourth portion formed of the plurality of second exposed fillers and etched by the plasma treatment together with the third portion,

wherein the first circuit pattern is in contact with the third portion and the fourth portion, and

wherein the third portion and the fourth portion have a surface roughness in a range of 0.5 μm to 1.0 μm.

4 . The circuit board of claim 3 , wherein the third portion and the fourth portion have a serrated shape.

5 . The circuit board of claim 3 , wherein the first circuit pattern includes a first metal layer disposed on the inner wall of the first grooves and in contact with the third portion and the fourth portion, and a second metal layer disposed on the first metal layer.

6 . The circuit board of claim 1 , wherein the through electrode includes a first metal layer disposed on the inner wall of the through hole and in contact with the first portion and the second portion, and a second metal layer disposed on the first metal layer.

7 . The circuit board of claim 1 , wherein the insulating layer further includes a plurality of second grooves provided on a lower surface of the insulating layer and spaced apart from each other in a horizontal direction, and

wherein the electrode part further comprises a second circuit pattern disposed in the second grooves.

8 . The circuit board of claim 7 , wherein the through hole overlaps at least one of the plurality of second grooves in a vertical direction,

wherein the through electrode is connected to the second circuit pattern, and

wherein the above plurality of fillers are not exposed through the plurality of second grooves.

9 . The circuit board of claim 1 , further comprising:

a protective layer disposed on the insulating layer and the first circuit pattern.

10 . The circuit board of claim 9 , wherein the protective layer has an opening, and

wherein the opening partially overlaps the first circuit pattern and the through electrode in the vertical direction.