LIQUID ETCHANT AND METHOD FOR FORMING TRENCH ISOLATION STRUCTURE USING SAME

摘要

Disclosed are a liquid etchant which is not easily affected by a trench structure, and a method for forming an isolation structure using the liquid etchant. Specifically disclosed is liquid etchant which contains hydrofluoric acid and an organic solvent. The organic solvent has a dH of not less than 4 but not more than 12 as determined by the Hansen solubility parameters, and a saturated solubility in water at 20°C of not less than 5%. The liquid etchant can be used in place of a conventional liquid etchant which is used in a semiconductor element forming process.