Abstract: A method for selective etching Si in the presence of silicon nitride and an etching composition with high Si/Si3N4 etching selectivity are disclosed. Particularly, the method for selective etching Si in the presence of silicon nitride is to apply the etching composition with high Si/Si3N4 etching selectivity in the etching process, and the etching composition with high Si/Si3N4 etching selectivity comprises about 0.5 wt. % to about 10 wt. % of at least one quaternary ammonium compound, about 5 wt. % to about 55 wt. % of at least one primary amine, about 15 wt. % to about 80 wt. % of at least one polyol, and about 10 wt. % to about 35 wt. % water based on total weight of the etching composition.

Abstract: A silicon etchant with high Si/SiO2 etching selectivity and its application are disclosed. The silicon etchant comprises at least one ketal and at least one quaternary ammonium hydroxide compound. The weight percentage of the ketal is 20˜99 wt. % based on the total weight of the etchant and the weight percentage of the quaternary ammonium hydroxide compound is 0.1˜10 wt. % based on the total weight of the etchant.

Abstract: A silicon etchant with high Si/SiO2 etching selectivity and its application are disclosed. The silicon etchant comprises at least one ketal and at least one quaternary ammonium hydroxide compound. The weight percentage of the ketal is 20˜99 wt. % based on the total weight of the etchant and the weight percentage of the quaternary ammonium hydroxide compound is 0.1˜10 wt. % based on the total weight of the etchant.

Abstract: The present invention provides an etchant composition suitable for etching metals Cu/Mo, wherein the composition comprises 1 to 25 wt % of hydrogen peroxide on the basis of the total weight of the composition; 0.1 to 15 wt % of amino acid on the basis of the total weight of the composition; 0.1 to 15 wt % of a pH stabilizer on the basis of the total weight of the composition; 0.01 to 2 wt % of fluorine-containing acid on the basis of the total weight of the composition; 0.01 to 3 wt % of an acidic pH adjuster on the basis of the total weight of the composition; and an aqueous medium. The present invention also provides a process for etching metals Cu/Mo with the etchant composition of the present invention.