Flip-chip packaging for optically interactive devices such as image sensors
and methods of assembly. In a first embodiment of the invention, conductive traces
are formed directly on the second surface of a transparent substrate and an image
sensor chip is bonded to the conductive traces. Discrete conductive elements are
attached to the conductive traces and extend below a back surface of the image
sensor chip. In a second embodiment, a secondary substrate having conductive traces
formed thereon is secured to the transparent substrate. In a third embodiment,
a backing cap having a full array of attachment pads is attached to the transparent
substrate of the first embodiment or the secondary substrate of the second embodiment.
In a fourth embodiment, the secondary substrate is a flex circuit having a mounting
portion secured to the second surface of the transparent substrate and a backing
portion bent over adjacent to the back surface of the image sensor chip.
