Automated Nearline Workflows for 3D NAND Process Control
In 2017, 3D NAND production will grow to produce over half of the bits in the flash market and continues to see growing investment from memory manufacturers. As these manufacturers transition to taller 3D stacks the complexity and cost continues to scale as well. Sub surface SEM and TEM metrology data provides manufacturers a tool for characterizing the entire depth of these challenging devices. Near fab workflows can produce this sub surface information in an automated and statistically meaningful way to help reduce cost and time to development. At 48L & 64L stack heights the available SEM cross section and TEM workflows are sufficient to guide development. As these devices grows to 64L & 96L gaining access to the entire stack becomes a more difficult proposition. In this presentation we will explain what challenges must be resolved to support taller stack heights with automated workflow techniques. The challenges associated with the metrology of 3D NAND TEM images will also be discussed as it relates to gathering large statistically meaningful data sets.