a self - aligned via structure and its method of manufacture comprising the steps of providing a semiconductor substrate , and then sequentially forming a conductive layer and a dielectric layer over the substrate . next , a hollow cavity is etched out in the dielectric layer . then , a photolithographic process is performed by coating a photoresist layer over the dielectric layer and the cavity , followed by creating a pattern of desired conductive lines so that portions of the photoresist layer overlaps with the cavity . subsequently , using the photoresist layer as a mask , the dielectric layer and the conductive layer are etched to form a multiple of conductive lines . thereafter , a selective liquid phase deposition is performed to deposit an oxide layer over the substrate in regions outside the photoresist - occupied regions . finally , the photoresist layer is removed to form the via structure of this invention in the oxide layer .