Methods of manufacturing a semiconductor structure are disclosed including a deep trench isolation in which a channel stop is formed in the form of an embedded impurity region in the substrate prior to the deep trench etch and formation of transistor devices (FEOL processing) on the substrate. In this fashion, the FEOL processing thermal cycles can activate the impurity region. The deep trench isolations are then formed after FEOL processing. The method achieves the reduced cost of forming deep trench isolations after FEOL processing, and allows the practice of sharing of a collector level between devices to continue. The invention also includes the semiconductor structure so formed.