A method of patterning a substrate. A sacrificial film is formed over a substrate and a pattern created therein. A first spacer layer is conformally deposited over the patterned sacrificial film and at least one horizontal portion of the first spacer layer is removed while vertical portions of the first spacer layer remain. A second spacer layer is conformally deposited over the patterned sacrificial film and the remaining portions of the first spacer layer. At least one horizontal portion of the second spacer layer is removed while vertical portions of the second spacer layer remain. Conformal deposition of the first and second spacer layers is optionally repeated one or more times. Conformal deposition of the first layer is optionally repeated. Then, one of the first or second spacer layers is removed while substantially leaving the vertical portions of the remaining one of the first or second spacer layers.