| 摘要 |
PURPOSE: A method for fabricating a semiconductor device is provided to improve step coverage between a high voltage device region and a region of a low voltage device and a flash device by forming a high voltage gate oxide layer during a process for forming an isolation layer. CONSTITUTION: A tunnel oxide layer(112) for a low voltage device, the first conductive layer(114) and a pad nitride layer are formed on a semiconductor substrate(110) in which the first region for forming a high voltage device and the second region for forming a flash device are defined. The pad nitride layer, the first conductive layer, the tunnel oxide layer and the semiconductor substrate are patterned to form a trench. After the trench is filled with an insulation layer, the insulation layer on the pad nitride layer is removed to form an isolation layer(118) by a planarization process. A hard mask layer is formed on the second region. A blanket etch process is performed to remove the pad nitride layer and the first conductive layer in the first region. The hard mask layer in the second region is eliminated. A high voltage gate oxide layer is formed in the first region. After the pad nitride layer in the second region is eliminated, the second conductive layer(130) is formed on the resultant structure.
|
