In various embodiments, semiconductor structures and methods to manufacture these structures are disclosed. In one embodiment, a method includes removing a portion of a semiconductor material to form a cavity that extends at least about one micron or greater below the surface of the semiconductor material, filling the cavity with a sacrificial material, forming a dielectric material over the sacrificial material and over at least a portion of the surface of the semiconductor material, and removing a portion of the dielectric material to form an opening to expose a portion of the sacrificial material, wherein the opening has a width that is substantially less than a width of the cavity and the dielectric material is rigid or substantially rigid. The method further includes removing the sacrificial material. Other embodiments are described and claimed.