In a manufacturing process of a semiconductor device, electroplating and
CMP have had a problem of increase in manufacturing costs for forming a
wiring. Correspondingly, an opening is formed in a porous insulating film
after a mask is formed thereover, and a conductive material containing Ag
is dropped into the opening. Further, a first conductive layer is formed
by baking the conductive material dropped into the opening by selective
irradiation with laser light. Subsequently, a metal film is formed over
the entire surface by sputtering, and the mask is removed thereafter to
have only the metal film remain over the first conductive layer, thereby
forming an embedded wiring layer formed with a stack of the first
conductive layer containing Ag and the second conductive layer (metal
film).