Fabrication of trenches with multiple depths on the same substrate

US7189628B1 · kind B1 · utility

Assignee

• LSI Logic Corporation · US

Inventors

• Mohammad R. Mirbedini · Redwood City, US
• Venkatesh P. Gopinath · Planada, US
• Hong Lin · Vancouver, US
• Verne Hornback · Camas, US
• Dodd Defibaugh · Camas, US
• Ynhi Le · Gresham, US

Key dates

• Filing date: Aug 31, 2004
• Grant date: Mar 13, 2007
• Expiry date: Jan 20, 2025

Classification

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

Abstract

Dual trench depths are achieved on the same wafer by forming an initial trench having a depth corresponding to the difference in final depths of the shallow and deep trenches. A second mask is used to open areas for the deep trenches over the preliminary trenches and for the shallow trenches at additional locations. Etching of the shallow and deep trenches then proceeds simultaneously.