Self-heating effects (SHEs) in 3-DV-NAND flash memory are investigated using simulations. First, temperature increase is estimated during the read operation, and a hot spot region along the bit-line is identified. Then, a novel bilayered macaroni filler is proposed to relieve the SHEs. A highly thermally conductive layer is plugged into the macaroni oxide filler as a heat sink. The heat dissipation efficiency is improved by up to 21% in the proposed structure. As a result, the reliability issues induced by SHEs can be avoided in V-NAND flash.