A method for wet etching of semiconductor wafers for generating a defined edge region by undercutting

摘要

Etchant comprises hydrofluoric acid, optionally with ammonium fluoride, as an active component. The etchant also contains a carboxylic acid, and is then diluted by up to 90% with deionized water. It is applied as a continuous stream to the wafer while it is rotated. Semiconductor wafer is wet etched to entirely remove a silicon dioxide layer from one side, and remove the layer on the opposite side by undercutting a desired area (a) only. The etchant contains hydrofluoric acid as an active component specific to silicon dioxide, and also contain at least one carboxylic acid. It is applied to the rotating wafer, and allowed to flow around the edge of the wafer and on to the side to be etched.