Multek Technologies Limited

Kwan Pen

Pui Yin Yu

Mark Zhang

A PCB has multiple stacked layers laminated together, the laminated stack includes regular flow prepreg and includes a recessed cavity, a bottom perimeter of which is formed by a photo definable, or photo imageable, polymer structure having a low adhesion to an underlying conductive layer, such as an LPI mixture. The LPI mixture defines cavity dimensions and enables the use of regular flow prepreg in the laminated stack.

Recessed cavity in printed circuit board protected by LPI

A PCB having multiple stacked layers laminated together. The laminated stack includes regular flow prepreg and includes a recessed cavity, a bottom perimeter of which is formed by a photo definable, or photo imageable, polymer structure, such as a solder mask frame, and a protective film. The solder mask frame and protective film protect inner core circuitry at the bottom of the cavity during the fabrication process, as well as enable the use of regular flow prepreg in the laminated stack.

Self-decap cavity fabrication process and structure

A selective segment via plating process for manufacturing a circuit board selectively interconnects inner conductive layers as separate segments within the same via. Plating resist is applied to a conductive layer of an inner core and then stripped off after an electroless plating process. Stripping of the electroless plating on the plating resist results in a plating discontinuity on the via wall. In a subsequent electroplating process, the plug non-conductive layer can not be plated due to the plating discontinuity. The resulting circuit board structure has separate electrically interconnected segments within the via.

Selective segment via plating process and structure

A selective segment via plating process for manufacturing a circuit board selectively interconnects inner conductive layers as separate segments within the same via. Plating resist is plugged into an inner core through hole and then stripped off after an electroless plating process. Stripping of the electroless plating on the plating resist results in a plating discontinuity on the via wall. In a subsequent electroplating process, the inner core layer can not be plated due to the plating discontinuity. The resulting circuit board structure has separate electrically interconnected segments within the via.

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Guandong, China

Kwan Pen