METHOD OF FORMING SELF-ALIGNED CONTACT

摘要

PURPOSE: A method of forming a self-aligned contact is to form spacers doubly on a gate electrode, thereby improving insulation between the gate electrode and a conductive layer for a landing pad. CONSTITUTION: A gate electrode(322) is formed on a semiconductor substrate(310). A silicon nitride layer is deposited on the gate electrode, followed by etching back it, to form the first spacer(326) thereon. A BPSG(borophosphosilicate glass) film(328) is deposited on the entire surface of the substrate and is etched to form a self-aligned contact. Then, an etch selection ratio of the BPSG film relative to the silicon nitride layer of the first spacer is controlled to secure a sufficient contact area. Thereafter, another silicon nitride layer is deposited on the entire surface of the substrate, followed by etching back it to form the second spacer(332).