| 摘要 |
PROBLEM TO BE SOLVED: To form a groove in a layer to be etched made of a dielectric material such that the groove has two wall faces each of which form a constant inclination angle from an opening to a lower end of the groove and which intersect at a predetermined angle.SOLUTION: A method of taper-etching a layer to be etched that is made of a dielectric material and has a top surface comprises the steps of: forming an etching mask 51, 52 with an opening on the top surface of the layer to be etched; and taper-etching a portion of the layer to be etched 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. |
