The technology relates to a damascene word line for a three dimensional array of nonvolatile memory cells. Partly oxidized lines of material such as silicon are made over a plurality of stacked nonvolatile memory structures. Word line trenches are made in the partly oxidized lines, by removing the unoxidized lines from the intermediate parts of the partly oxidized lines, leaving the plurality of oxidized lines at the outer parts of the plurality of partly oxidized lines. Word lines are made in the word line trenches over the plurality of stacked nonvolatile memory structures.