We demonstrate the application of 3D tomography by FIB-SEM to analyze channel holes in 3D-NAND. We automatically analyze the 3D channel profiles for size, shape, and placement from the reconstructed full 3D volume. As the data contains thousands of holes, and each hole is sampled with a resolution of a few nanometer in 3D, this method provides a vast amount of data. We analyze individual holes as well as a full population of holes, from a solid statistical basis. Such information is beneficial in monitoring and controlling the etch process of the HAR channel holes in 3DNAND fabrication.