The present invention provides a systems and methods to perform an
electrical test on a substrate assembly used as a TFT array substrate of
a liquid-crystal device without detaching a mounted external IC. The
substrate assembly can include a substrate, a peripheral circuit embedded
in the substrate, a first wiring arranged on the substrate, and an
external IC, mounted on the substrate, and having a first terminal
connected to an interconnection portion arranged on the first wiring. The
substrate assembly can further include a second wiring which extends from
the interconnection portion in such a manner that the second wiring is
routed in a portion of the substrate facing the integrated circuit, and a
first external circuit connection terminal arranged on the second wiring
in a portion of the substrate not facing the integrated circuit. The
external IC is thus tested through the external circuit connection
terminal.