Keyhole at the top metal level prefilled with photoresist to prevent passivation damage even for a severe top metal rule

摘要

A planarized surface of a photoresist layer is formed above a layer formed over a hole in a blanket, conformal, silicon nitride layer which in turn is formed above a keyhole in metallization with SOG layers therebetween on the surface of a semiconductor device. A blanket, first photoresist layer was formed above the blanket silicon nitride to fill the damage to the surface caused by the hole. Then the first photoresist layer was stripped leaving a residual portion of the first photoresist layer filling the hole. Next, a blanket, second photoresist layer was formed above the blanket layer. The hole has a neck with a width from about 200 Å to about 500 Å and the hole has a deep, pocket-like gap with a cross-section with a width from about 500 Å to about 1200 Å below the narrow neck.