Taper-etching method and method of manufacturing near-field light generator

摘要

A method of taper-etching a layer to be etched that is made of a dielectric material and has a top surface. The method includes the steps of: forming an etching mask with an opening on the top surface of the layer to be etched; and taper-etching a portion of the layer to be etched, the portion being exposed from the opening, by reactive ion etching so that a groove having two wall faces intersecting at a predetermined angle is formed in the layer to be etched. The step of taper-etching employs an etching gas containing a first gas contributing to the etching of the layer to be etched and a second gas contributing to the deposition of a sidewall protective film, and changes, during the step, the ratio of the flow rate of the second gas to the flow rate of the first gas so that the ratio increases.

主权项

1. A taper-etching method for taper-etching a layer to be etched, the layer to be etched being made of a dielectric material and having a top surface, the taper-etching method comprising the steps of:
forming an etching mask on the top surface of the layer to be etched, the etching mask having an opening; and taper-etching a portion of the layer to be etched, the portion being exposed from the opening, by reactive ion etching so that a groove having two wall faces that intersect at a predetermined angle is formed in the layer to be etched, wherein: the step of taper-etching employs an etching gas containing a first gas contributing to the etching of the layer to be etched and a second gas contributing to deposition of a sidewall protective film, and changes, during the step, a ratio of a flow rate of the second gas to a flow rate of the first gas so that the ratio increases; the layer to be etched is made of SiO2 or SiON; the etching mask contains elemental Al; and the second gas contains N2.