Embedded cavity in printed circuit board by solder mask dam

A method of manufacturing a printed circuit board comprising:

• a. forming an inner core structure having a first surface;
• b. forming a photo imageable polymer structure on the first surface of the inner core structure, wherein the photo imageable polymer structure forms a boundary within which a cavity is formed;
• c. removing a section from a prepreg layer, wherein the section forms a cut-out section through an entire thickness of the prepreg layer, and the cut-out section has a perimeter that substantially matches a footprint of the boundary of the photo imageable polymer structure;
• c. forming a printed circuit board stack up, wherein the printed circuit board stack up comprises the inner core structure, the prepreg layer positioned against the first surface of the inner core structure such that the photo imageable polymer structure fits within the cut-out section of the prepreg layer, and a non-conductive layer or a conductive layer positioned against the prepreg layer such that the cavity is formed within the printed circuit board stack up;
• and
• d. laminating the printed circuit board stack up, thereby forming a laminated stack;