A method of making an interposer in which at least two dielectric layers
are bonded to each other to sandwich a plurality of conductors
there-between. The conductors each electrically couple a respective pair
of opposed electrical contacts which are formed within and protrude from
openings which are also formed within the dielectric layers as part of
this method. The resulting interposer is ideally suited for use as part
of a test apparatus to interconnect highly dense patterns of solder ball
contacts of a semiconductor chip to lesser dense arrays of contacts on
the apparatus's printed circuit board.