Abstract: A semiconductor device includes: a field oxide layer formed on a semiconductor substrate; a transistor having an active region formed on a semiconductor substrate; an interlayer insulating layer formed on the transistor and the field oxide; and a tapered contact hole exposing the active region adjacent to the field oxide layer, wherein an upper portion of the tapered contact hole is wider than a lower portion thereof so that the field oxide is not etched during the contact hole etching process.

Abstract: In the formation of a via contact hole of a semiconductor device, a polymer layer on the sidewall of a photoresist layer and via contact hole is effectively removed and the short of the via contact hole does not occur. For achieving such purpose, a wafer is cleaned in deionized water being added with CO.sub.2 gas during the process used for forming the via contact hole, and a protecting film (Al.sub.2 O.sub.3) is formed on a metal layer. Thereafter, since the polymer layer and a part of the photoresist layer is removed, the metal layer is not eroded and the polymer layer is completely removed.