Method for forming lining oxide in shallow trench isolation incorporating pre-annealing step

• Main Authors: Lai, Jun-Yang, Wang, Jih-Hwa, Tsai, Chou-Jie, Huang, Chin-Te, Yeh, Su-Yu, Shieh, Meng-Shiun, Hsieh, Jang-Cheng, Lin, Chung-Te
• Format: Patent
• Language: English
• Published: 03.09.2002

The present invention generally relates to a method for forming lining oxide in an opening for a shallow trench isolation (STI) and more particularly, relates to a method for forming lining oxide in an opening for a shallow trench isolation incorporating a pre-annealing step for repairing structural damages incurred in the silicon substrate by a dry etching process for forming the opening. A method for forming lining oxide in an opening for a shallow trench isolation and a method for forming a shallow trench isolation incorporating a lining oxide layer are described. In the method for forming lining oxide, a silicon substrate is first provided, followed by a process of forming a pad oxide layer and a silicon nitride mask sequentially on top of the silicon substrate. A trench opening is then patterned and formed in the silicon substrate for the shallow trench isolation. The silicon substrate is then annealed at a temperature of at least 1,000° C. in a furnace in an environment that contains not more than 10 vol. % oxygen. A lining oxide layer is formed in the same furnace used for annealing the structure of the trench opening in the silicon substrate.