Transforming a valve metal layer into a template comprising a plurality of spaced (nano)channels and forming spaced structures therein

At least one embodiment relates to a method for transforming at least part of a valve metal layer into a template that includes a plurality of spaced channels aligned longitudinally along a first direction. The method includes a first anodization step that includes anodizing the valve metal layer in a thickness direction to form a porous layer that includes a plurality of channels. Each channel has channel walls and a channel bottom. The channel bottom is coated with a first insulating metal oxide barrier layer as a result of the first anodization step. The method also includes a protective treatment. Further, the method includes a second anodization step after the protective treatment. The second anodization step substantially removes the first insulating metal oxide barrier layer, induces anodization, and creates a second insulating metal oxide barrier layer. In addition, the method includes an etching step.