| 摘要 |
PURPOSE: A method for forming a well of a semiconductor device is provided to form conductive wells, which are different, with an exact pattern by using a self-alignment. CONSTITUTION: The method includes four steps. The first step is to sequentially deposit a pad oxide film(3) and a nitride film(4) on the upper portion of a substrate(1) on which an isolating structure(2) is formed and to deposit an oxide film(5) on the upper portion of the nitride film. The second step is to coat, expose and develop the first photoresist on the entire surface of the upper portion of the oxide film to form the first photoresist pattern positioning on the upper portion of the oxide film positioning on the right substrate of the isolating structure and to remove the exposed oxide film with an etching process using the first photoresist pattern as an etching mask to expose the nitride film positioning on the left substrate of the isolating structure and then to implant an impurity ion to form a P well(6) in the substrate. The third step is to remove the first photoresist pattern and coat and flatten the second photoresist on the entire surface of the upper portion of the structure to form the second photoresist pattern exposing the upper portion of the oxide film. The fourth step is to remove the exposed oxide film and to implant an impurity ion with an ion implanting process using the exposed nitride film and the pad oxide film under the exposed nitride film as an ion implanting buffer, thereby form an N well(7) in the right substrate of the isolating structure.
|
