Next methods deposit sacrificial layer 4852 (sacrificial layer 1) on upper level contact layer 4850 as illustrated in FIG. 48C. Sacrificial layer 4852 may be in the range of 10 to 500 nm thick and be formed using conductor, semiconductor, or insulator materials such as materials described further above with respect to lower level contact layer 3430, semiconductor layers 3420 and 3425, and insulato