The present invention provides an optoelectronic packaging substrate comprising
optical wiring having an optical waveguide and electric wiring having a metal wiring
and characterized in that the optical waveguide is composed of a core layer, a
side face clad layer formed in the side circumference of the core layer, an upper
clad layer formed on the upper side of the core layer and the side face clad layer,
and a lower clad layer formed on the lower side of the core layer and the side
face clad layer; that the metal wiring is formed in at least one of the side face
clad layer, the upper clad layer, and the lower clad layer; and that the core layer,
the side face clad layer, and the clad layer bearing the metal wiring are made
of a silicon-based material layer of a branched type polysilane mixed with a silicone compound.
