| 摘要 |
PURPOSE: A method for forming device isolation film of semiconductor device and its structure are provided to control isolation length effectively without loss of design rule by using epitaxial process. CONSTITUTION: After trench formation by conventional method, oxide spacer is formed and remain only along the side wall by anisotropic etching. The spacer is removed by wet-etching process to form grooves on the bottom of the trench and etching excessively a part of pad-oxide layer. The edge of the trench is made smooth to reduce kink effect by oxidation process. A high density oxide plasma layer(HDP) is deposited on the top surface of the whole structure to fill up the trench and then made flat by CMP process. A pad oxide and nitride layer and some of HDP are removed to form device isolation film. Grooves on the bottom of trench play a role to make the distance of device isolation lengthen.
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