A new method for planarizing silicon dioxide surfaces in semiconductor structures. Starting with a structure of an underlying layer (for instance a layer of metal lines) a layer of oxide is deposited and profiled by positive tone imaging. A layer of PPMS is deposited. Using the mask of the starting structure, the PPMS layer is exposed changing the PPMS to PPMSO in the exposed regions. The unexposed PPMS is removed, the PPMSO (unexposed regions of the PPMS) are planarized, this planarization can proceed to the point where no more PPMSO is present (the PPMSO “columns” are removed together with the intra-layer of patterned oxide). The surface thus created shows excellent planarity, this surface can be further planarized down to the top level of the underlying pattern, if it is desirable to do so.