Method of making an article comprising a tandem groove, and article produced by the method

Tandem grooves (or other groove-like features) with controlled transition between the narrow and wide portion of the groove can be formed in a semiconductor surface, exemplary a (100) Si surface, by a method that comprises patterning a first masking layer such that the resulting aperture in the masking layer defines the tandem groove, re-covering the narrow part of the aperture with a second masking layer, subjecting the wide portion of the aperture to an initial etch, removing the second masking layer from the narrow part of the aperture, and subjecting the aperture to a further etch such that both the wide and the narrow portions of the tandem groove are completed. The inventive method is advantageously used to produce grooves that allow attachment of a coated optical fiber to a Si substrate.