Circuit board structure and manufacturing method thereof

A manufacturing method of a circuit board structure, comprising:

• providing a redistribution circuit structure layer comprising a plurality of first connecting pads;
• providing a connection structure layer comprising a substrate and a plurality of conductive paste pillars penetrating the substrate, wherein the connection structure layer is in a B-stage state;
• providing a build-up circuit structure layer comprising a plurality of second connecting pads, wherein a line width and a line spacing of the redistribution circuit structure layer are smaller than a line width and a line spacing of the build-up circuit structure layer;
• and
• pressing the redistribution circuit structure layer, the connection structure layer, and the build-up circuit structure layer together, so that the connection structure layer is located between the redistribution circuit structure layer and the build-up circuit structure layer, wherein the first connecting pads are electrically connected to the second connecting pads respectively through the conductive paste pillars, the first connecting pads and the second connecting pads are respectively embedded in two opposite surfaces of the substrate, and the connection structure layer changes from the B-stage state to a C-stage state.