METHOD AND APPARATUS FOR ETCHING THIN LAYER

Method and apparatus for etching a thin layer including silicon nitride formed on a substrate are disclosed. Etchant including phosphoric acid and water is supplied on the substrate so that a liquid layer is formed on the substrate. The thin layer is etched by reaction between the thin layer and the etchant. Thickness of the liquid layer is measured to detect variation in the thickness of the liquid layer while etching the thin layer. Variation in the concentration of the phosphoric acid and the water is calculated based on the variation in the thickness of the liquid layer. Water is supplied on the substrate based on the variation in the concentration of the phosphoric acid and the water so that the concentration of the phosphoric acid and the water becomes a predetermined value. 本发明公开了用于蚀刻薄层的方法和设备，所述薄层包括形成在基板上的氮化硅。在所述基板上供应包括磷酸和水的蚀刻剂，使得在所述基板上形成液层。通过在所述薄层和所述蚀刻剂的反应来蚀刻所述薄层。测量所述液层的厚度，以在蚀刻所述薄层的同时检测所述液层的所述厚度的变化。基于所述液层的所述厚度的所述变化来计算所述磷酸和所述水的浓度的变化。基于所述磷酸和所述水的所述浓度的所述变化在所述基板上供应水，使得所述磷酸和所述水的所述浓度变为预定值。