A method to form sub-lithographic trench structures in a substrate and an integrated circuit comprising sub-lithographic trench structures in a substrate. The method includes forming sets of trenches with a lithographic mask and filling the sets of trenches with sets of step spacer blocks comprising two alternating spacer materials which are separately removable from each other. In one embodiment, the trench structures formed are one-nth the thickness of the lithographic mask's feature size. The size of the trench structures being dependent on the thickness and number of spacer material layers used to form the set of step spacer blocks. The number of spacer material layers being n/2 and the thickness of each spacer material layer being one-nth of the lithographic mask's feature size.