Method of filling shallow trenches

US8685830B2 · kind B2 · utility

Assignee

• SHANGHAI HUA HONG NEC ELECTRONICS CO., LTD. · CN

Inventors

• Fan Chen · Shanghai, CN
• Xiongbin Chen · Shanghai, CN
• Kai Xue · Shanghai, CN
• Keran Zhou · Shanghai, CN
• Jia Pan · Shanghai, CN
• Hao Li · 安丰镇, CN
• Yongcheng Wang · Dongguan, CN

Key dates

• Filing date: Dec 5, 2012
• Grant date: Apr 1, 2014
• Expiry date: Dec 5, 2032

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/76283
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method of filling shallow trenches is disclosed. The method includes: successively forming a first oxide layer and a second oxide layer over the surface of a silicon substrate where shallow trenches are formed in; etching the second oxide layer to form inner sidewalls with an etchant which has a high etching selectivity ratio of the second oxide layer to the first oxide layer; growing a high-quality pad oxide layer by thermal oxidation after the inner sidewalls are removed; and filling the trenches with an isolation dielectric material. By using this method, the risk of occurrence of junction spiking and electrical leakage during a subsequent process of forming a metal silicide can be reduced.