摘要 |
According to the selective etching process, when two different material layers, e.g. a first material layer (a silicon nitride film) and a second material layer (a silicon film) are coexistent, the etch selectivity of the second material layer with regard to the wet etch for the first material layer, an object of etch, can be improved by transforming the entire or partial surface of the second material layer with a third material (an oxidizing agent) having high selectivity for the first material layer prior to or during the wet etch. As a result, the second material layer can be prevented from being damaged. In addition, when the inventive process is applied to the LOCOS process, it is preventive of the substrate damage caused by the destruction of the pad oxide film resulting from so-called white ribbon phenomenon.
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