METHOD OF FORMING ALIGNMENT KEY OF SEMICONDUCTOR ELEMENT

摘要

PURPOSE: A method of forming an alignment key of semiconductor element is to form a pre-alignment mark and a scribed prealignment mark using the same method, thereby increasing an accuracy of the prealignment for a wafer. CONSTITUTION: A method of forming an alignment key of a semiconductor element comprises the steps of: forming a nitride film on a wafer(11); etching the nitride film and the wafer alternatively, such that a portion on which a pre-alignment mark is formed can be protruded; forming a trench on the wafer; etching an oxide film(14) on the resultant created by the etching so as to embed the trench; polishing the oxide film so as to expose the nitride film; removing the nitride film; etching the oxide film with a predetermined thickness, so as to expose a protruded portion(11a) of the wafer; and depositing a polysilicon layer(15) with the predetermined thickness on an upper portion of the resultant created by the etching of the oxide film. A depth of the trench is about 2400 to 2600 angstrom.