Printed circuit board with circuitized cavity and methods of producing same

A method of metallizing a cavity in a printed circuit board, comprising the steps of:

• providing the printed circuit board having the cavity formed therein, the printed circuit board also having an internal circuit structure between a front surface and a back surface of the printed circuit board, wherein the cavity is formed through the following steps:
• sandwiching a sticker sheet between first and second metallized dielectric layers, the second metallized dielectric layers and the sticker sheet each having a window that is registered with the other window, thereby creating the cavity;
• laying a flexible release layer above the second metallized dielectric layers;
• laying a sheet of material on the release layer over the cavity, the material being soft and conformable at room temperature to seal a bottom periphery of the cavity yet viscous to effectively dam the periphery;
• and
• subjecting the first and second metallized dielectric layers, sticker sheet, release layer and material to heat and pressure, the pressure forcing the material into the cavity to seal the bottom periphery of the cavity before the heat and pressure cause the sticker sheet to flow beyond the seal, the heat and pressure causing the sticker sheet to flow and conform to the seal, curing the sticker sheet to bind the first and second metallized dielectric layers to each other, and creating a fillet of dielectric around sides of the cavity;
• disposing a conductive layer conformally to the cavity;
• disposing a photo resist conformally on the conductive layer;
• exposing the photo resist to delineate a circuit feature pattern in the cavity;
• developing the photo resist;
• and
• etching the conductive layer through the photo resist to create a circuit feature from the circuit feature pattern in the cavity.