Etch Stop Protection of Silicon And/Or Reactive Silicides Under Aluminum in Reactive Ion Etching
Original Publication Date: 1988-May-01
Included in the Prior Art Database: 2005-Feb-15
Protection of silicon (SI) or silicides (e.g., TiSi2) during exposure to an aluminum (Al) reactive ion etching (RIE) plasma containing boron/ chlorine compounds is achieved by forming a nickel silicide (NiSi) on the Si and/or silicide surfaces prior to Al deposition. The following process is performed after opening contact holes through an insulating film layer, e.g., silicon dioxide (SiO2), and complete removal of photoresist. Thus, the surface is comprised mainly of clean SiO2, but with Si and/or TiSi2 surfaces exposed through the contact holes. 1. Deposit Ni over the entire surface. 2. Anneal at 350-500 degrees Celsius for about one hour. This step forms NiSi where Ni is in contact with Si or TiSi2 and leaves elemental Ni on the SiO2 surface. 3.