US Patent 7825030 Method of forming a spacer

A sacrificial layer and wet etch are used to form a sidewall spacer so as to prevent damage to the structure on which the spacer is formed and to the underlying substrate as well. Once the structure is formed on the substrate a spacer formation layer is formed to cover the structure, and a sacrificial layer is formed on the spacer formation layer. The sacrificial layer is wet etched to form a sacrificial layer pattern on that portion of the spacer formation layer extending along a sidewall of the structure. The spacer is formed on the sidewall of the structure by wet etching the spacer formation layer using the sacrificial layer pattern as a mask.