Substrate for printed circuit board and printed circuit board

1 . A substrate for a printed circuit board, the substrate comprising:

a base film having a main surface; and

an electrically conductive layer disposed on the main surface,

wherein the base film is made of a fluororesin containing a filler made of silica particles,

wherein the electrically conductive layer is a layer including a plurality of electrically conductive particles bonded together, and

wherein an amount of nitrogen present in the main surface is 0.2 atomic percent or more,

wherein the base film includes a fluororesin layer between the filler and the electrically conductive layer,

wherein, in a cross section orthogonal to the main surface, the fluororesin layer has a predetermined range of distance between the filler and the electrically conductive layer, and a total length of the fluororesin layer between the filler and electrically conductive layer in a direction parallel to the main surface within the range of the distance between the filler and the electrically conductive layer is 5% or more of an entire length of the main surface.

2 . The substrate for a printed circuit board according to claim 1 ,

wherein the electrically conductive particles are particles containing copper or silver as a main component.

3 . The substrate for a printed circuit board according to claim 1 ,

wherein a thickness of the electrically conductive layer is 0.05 μm to 2.0 μm.

4 . The substrate for a printed circuit board according to claim 1 ,

wherein an average particle diameter of the electrically conductive particles is 1 nm to 500 nm.

5 . The substrate for a printed circuit board according to claim 1 ,

the substrate further comprising a copper plating layer disposed on the electrically conductive layer.

6 . The substrate for a printed circuit board according to claim 5 ,

wherein the copper plating layer is an electroless copper plating layer or an electrolytic copper plating layer.

7 . The substrate for a printed circuit board according to claim 1 ,

wherein the fluororesin is a polytetrafluoroethylene.

8 . The substrate for a printed circuit board according to claim 1 , wherein an average particle diameter of the filler is 0.3 μm to 4.0 μm.

9 . The substrate for a printed circuit board according to claim 1 , wherein a volume ratio of the filler to the fluororesin is 1.2 or more.

10 . The substrate for a printed circuit board according to claim 1 , wherein the predetermined range of distance between the filler and the electrically conductive layer is between 0.01 μm to 0.5 μm.

11 . A printed circuit board comprising:

a base film having a main surface; and

a wire disposed on the main surface,

wherein the base film is made of a fluororesin containing a filler made of silica particles,

wherein the wire includes an electrically conductive layer disposed on the main surface,

wherein the electrically conductive layer is a layer including a plurality of electrically conductive particles bonded together,

wherein the base film includes a fluororesin layer between the filler and the electrically conductive layer,

wherein, in a cross section orthogonal to the main surface, the fluororesin layer has a predetermined range of distance between the filler and the electrically conductive layer, and a total length of the fluororesin layer between the filler and electrically conductive layer in a direction parallel to the main surface within the range of the distance between the filler and the electrically conductive layer is 5% or more of an entire length of the main surface, and

wherein an amount of nitrogen present in the main surface is 0.2 atomic percent or more.

12 . The printed circuit board according to claim 11 , wherein the predetermined range of distance between the filler and the electrically conductive layer is between 0.01 μm to 0.5 μm.