Fabrication of fully embedded board-level optical interconnects and optoelectronic printed circuit boards

The manufacturing processes of an optoelectronic printed circuit board (OEPCB) with an embedded board-level polymeric waveguide and vertical-optical channel interconnection are presented in this paper. The optoelectronic packages contain one vertical cavity surface emitting laser (VCSEL), one photo detector (PD), surface mount technology (SMT) components and one fully embedded board-level optical interconnects. The first step is to fabricate a polymeric waveguide structure with two 45-degree mirrors, and then embedded the waveguide in the center with two prepreg to form a horizontal optical channel inside a printing circuit board by a two-step laminating process. The vertical-optical channel is made by a three-step process, conformal mask forming, laser ablating and copper etching. This vertical channel is connected to the mirror of the horizontal waveguide. A wide, collimated optical beam couples a package board across a narrow, long air gap and provides a large tolerance to misalignment during the SMT process. Key process steps will be discussed and X-ray images will be presented in this paper. Also, characterization measurements of the important electrical and optical parameters are discussed in this paper.