| 摘要 |
PROBLEM TO BE SOLVED: To reduce acid consumption, without lowering the effect of the etching liq. SOLUTION: Nitric acid, hydrofluoric acid and surfactant, as required, are mixed to prepare an etching mixture, hydrofluoric acid or hydrofluoric acid plus nitric acid is added to the mixture, and a semiconductor wafer is etched. The etching mixture is prepared, using nitric acid having a concn. of 70 wt.% or higher and hydrofluoric acid having a concn. of 50 wt.% or higher or using nitric acid having a concn. of 70 wt.% or higher and hydrofluoric acid having a concn. of 50 wt.% or more. |
