| 摘要 |
An etchant composition is provided to etch a silicon oxide layer selectively when a silicon oxide layer and a nitride layer or a titanium nitride layer is exposed simultaneously on a wafer and to improve selectivity ratio. An etchant composition comprises 1-40 wt% of ammonium fluoride(NH4F); 1-20 wt% of an inorganic acid except hydrofluoric acid; and the balance of water. Preferably the inorganic acid is at least one selected from the group consisting of phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid, borohydrofluoric acid, perchloric acid, iodic acid and bromic acid. Preferably the composition comprises further 0.001-1 wt% of a fluorine-based nonionic surfactant or an anionic surfactant, and/or 1-30 wt% of an organic acid.
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