Self-aligned CMP Integrated Study of 70nm Node NAND Flash Memory On Floating Gate Electrode

摘要

For NAND flash memory, the feature size scaling will suffer from electrical and reliability challenges. First, as the word line scaling down, the capacitance coupling among unrelated floating gate would increase which leads to Vth shift and widen distribution. Secondary, the required floating gate height should be reduced due to disturb between memories cell. Therefore, the floating gate height by means of self aligned STI (SA-STI) and poly CMP process need to be well controlled or the characteristics of cell function will be critical challenge. Although the technologies of SA-STI and poly CMP both are popular for floating gate (FG) and active area (AA) in NAND flash process for a long time, we would like to show the scaling cell structure and introduce this technology node integration process. This paper describes the characteristics of self-align STI and poly CMP process applying into 70nm node high density NAND flash memories. It should be mentioned that this integrated process is easy to direct shrink to 70nm generation beyond.