| 摘要 |
A method for manufacturing a flash memory device includes: forming a floating gate on a tunnel oxide film formed on a semiconductor substrate; forming an ONO film on the floating gate; performing a well implant process to form a well on the semiconductor substrate; and performing an ashing process and a cleaning process using at least two of H<SUB>2</SUB>SO<SUB>4</SUB>, H<SUB>2</SUB>O<SUB>2</SUB>, HF, H<SUB>2</SUB>O, and O<SUB>3</SUB>. As a result, roughness is not generated on the upper surface of the ONO film which tends to cause data retention failures of the flash memory device during a high temperature operating life (HTOL) testing process, making it possible to improve the reliability of the flash memory device.
|
