PROCESS FOR THE ANISOTROPIC AND SELECTIVE DRY ETCHPROCESS FOR THE ANISOTROPIC AND SELECTIVE DRY ETCHING OF NITRIDE OVER THIN OXIDES ING OF NITRIDE OVER THIN OXIDES

摘要

In a method for anisotropically and selectively etching a nitride layer in a semiconductor device having a layer of nitride overlying a layer of oxide on a silicon substrate, first, the substrate is placed between the upper electrode and the lower electrode of a reactive ion etching device. Then, the etching process is commenced. The endpoint of the etch is determined by measuring the change in voltage between the upper and lower electrodes. The etching process is terminated some time after determining that the chaange in the measured voltage is approximately equal to zero. The change in the measured voltage is approximately equal to zero when the layer of nitride is completely etched from the layer of oxide.