Method of manufacturing multi-layer circuit board and multi-layer circuit board manufactured by using the method

1. A method of manufacturing a circuit board, the method comprising:

forming a second conductive circuit layer on a first surface of a second prepreg, the second conductive circuit layer having a centerline being parallel to the first surface of the second prepreg and dividing the second conductive circuit layer into an upper portion and a lower portion opposite to the upper portion;

stacking a first prepreg on a first surface of the second conductive circuit layer; and

forming at least one of a first circuit layer and a third circuit layer on at least one of a first surface of the first prepreg and a second surface opposite of the first surface of the second prepreg,

wherein, in the stacking the first prepreg, the first prepreg and the second prepreg are in a semi-cured state and the first prepreg and the second prepreg flow between patterns of the second conductive circuit layer in the semi-cured state,

wherein in the stacking the first prepreg, the second conductive circuit layer submerged into each of the stacked first and second prepregs is heated so that the first prepreg forms a first recessed portion and the second prepreg forms a second recessed portion,

wherein the upper portion of the second conductive circuit layer is disposed in the first recessed portion and the lower portion opposite to the first portion is disposed in the second recessed portion, and

wherein the first prepreg and the second prepreg are symmetrically stacked with respect to the centerline of the second conductive circuit layer protruding into each of the first and second prepregs after the submersion of the second conductive circuit layer;

wherein the centerline of the second conductive circuit layer passes through a conductive material of the second conductive circuit layer.

2. The method of claim 1 , wherein the first prepreg and the second prepreg having the same characteristics.

3. The method of claim 1 , wherein the forming of the second conductive circuit layer comprises:

forming a second conductive layer on the first surface of the second prepreg; and

applying a subtractive process on the second conductive layer to form the second conductive circuit layer,

wherein the second conductive layer is formed by stacking the second conductive layer on the second prepreg or plating the second conductive layer on the second prepreg.

4. The method of claim 1 , wherein the forming of the second conductive circuit layer comprises: forming the second conductive circuit layer on the first surface of the second prepreg by using an additive process.

5. The method of claim 1 , wherein between the stacking of the first prepreg and the forming of the first or third circuit layer further comprising:

processing a via hole formed on at least one conductive layer, wherein

a first conductive layer formed on the first surface of the first prepreg and a third conductive layer formed on the second surface opposite of the first surface of the second prepreg;

curing the first prepreg and the second prepreg; and

plating an inner surface of the via hole

wherein the forming of the first circuit layer comprises: stacking and forming the first conductive layer and the first prepreg,

wherein the forming of the third circuit layer comprises: stacking and forming the third conductive layer and the second prepreg.

6. The method of claim 5 , wherein the processing of the via hole comprises:

patterning the at least one conductive layer by using a subtractive process thereby the at least one conductive layer corresponds to a via; and

forming the via hole by performing resin etching on at least one surface of the circuit board.

7. The method of claim 1 , wherein the forming of the first and third circuit layer comprises:

providing at least one of a first conductive layer on the first surface of the first prepreg and a third conductive layer on the second surface opposite of the first surface of the second prepreg; and

forming the first and third conductive layer as the first and third circuit layer by using a subtractive process,

wherein the first conductive layer is formed by stacking the first conductive layer on the first prepreg in the stacking of the first prepreg, and the third conductive layer is formed by stacking the third conductive layer on the second prepreg in the forming of the second conductive circuit layer.

8. The method of claim 1 , wherein the first or third circuit layer is formed by using the additive process.

9. The method of claim 1 , further comprising sequentially forming a third prepreg and a fourth circuit layer on a first surface of the first circuit layer or a first surface of the third circuit layer.

10. The method of claim 1 , wherein each of the stacked first and second prepregs of the circuit board has the same thickness.

11. The method of claim 1 , wherein each of the stacked first and second prepregs has a viscosity between 4,000 Pa·s and 10,000 Pa·s during the stacking the second prepreg.

12. The method of claim 1 , wherein a maximum number of circuit layers included in the circuit board is three.