Resin flow restriction process and structure

A method of manufacturing a printed circuit board, the method comprising:

• adding a first solder mask to a first copper layer of a first core having a first opening;
• bonding a first FR4 laminate to the first solder mask;
• adding a second solder mask to a second copper layer of a second core having a second opening;
• bonding a second FR4 laminate to the second solder mask;
• mating the first core to the second core such that the first FR4 laminate is opposite the second FR4 laminate and the first opening and the second opening line up;
• adding a prepreg resin between the first copper layer and the second copper layer but not between the first FR4 laminate and the second FR4 laminate;
• and
• laminating the first core to the second core, wherein the first FR4 laminate and the second FR4 laminate reduce the prepreg resin flowing into the first and second openings.