Dummy core restrict resin process and structure
AssigneeMultek Technologies Limited
InventorsJ L Zhou, Pui Yin Yu
Life of this patent
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Abstract
A printed circuit board (PCB) has multiple layers, where select portions of inner layer circuitry, referred to as inner core circuitry, are covered by a coverlay material and the covered inner core circuitry is exposed from the remaining layers of the PCB. The PCB having covered inner core circuitry is formed using a dummy core plus coverlay process. The select inner core circuitry is part of an inner core. The inner core corresponding to the covered inner core circuitry forms a flexible PCB portion. The flexible PCB portion is an extension of the remaining adjacent multiple layer PCB. The remaining portion of the multiple layer PCB is rigid. The inner core is common to both the flexible PCB portion and the remaining rigid PCB portion.
Claims27
A method of manufacturing a printed circuit board comprising:
- a. forming an inner core structure having an inner core circuitry on at least one surface of the inner core structure;
- b. applying a coverlay material over the inner core circuitry;
- c. forming a printed circuit board stack up, wherein the printed circuit board stack up comprises the inner core structure, a dummy core, one or more non-conductive layers and one or more conductive layers, wherein the dummy core is a metal clad base material, wherein the dummy core is stacked on the coverlay material;
- d. laminating the printed circuit board stack up, thereby forming a laminated stack;
- e. forming a depth controlled rout from a surface of the laminated stack to the dummy core and around a perimeter of the dummy core, wherein a portion of the laminated stack within the perimeter of the rout and to a depth including the dummy core forms a laminated stack cap;
- f. removing the laminated stack cap, thereby exposing the coverlay material and forming a flexible portion of the printed circuit board.
A method of manufacturing a printed circuit board comprising:
- providing a first core including core circuitry;
- providing a dummy core having a conductive layer adhered to a base material, wherein the dummy core defines one or more overlay areas and one or more open areas extending therethrough that are free of material;
- forming a printed circuit board stack up, wherein the printed circuit board stack up includes the first core, the dummy core, a prepreg layer and one or more conductive layers, wherein the dummy core is disposed adjacent the first core and the prepreg layer is disposed adjacent the dummy core, wherein the first core is disposed adjacent a first surface of the dummy core and the prepreg layer is disposed adjacent a second surface of the dummy core, the second surface reverse of the first surface;
- laminating the printed circuit board stack up, thereby forming a laminated stack;
- depth controlled routing from a surface of the laminated stack to the dummy core and around a perimeter of the one or more overlay areas, wherein a portion of the laminated stack within the perimeter of the one or more overlay areas and to a depth including the dummy core forms a laminated stack cap;
- and
- removing the laminated stack cap, wherein the laminated stack cap separates from a remainder of the laminated stack at a boundary of the dummy core and the first core.
Dependencies are inferred from the claim text.