Method for forming a ring-shape capacitor

US5721168A · kind A · utility

Assignee

• POWERCHIP SEMICONDUCTOR CORP. · TW

Inventor

• Shye-Lin Wu · 東區, TW

Key dates

• Filing date: Dec 2, 1996
• Grant date: Feb 24, 1998
• Expiry date: Dec 2, 2016

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10B12/318

Abstract

A method for forming a ring-shape capacitor in a dynamic random access memory is disclosed. The present invention includes forming a first dielectric layer on a substrate. After a silicon nitride layer is formed on the first dielectric layer, a first doped polysilicon layer is formed on the silicon nitride layer, and a second dielectric layer is formed on the first doped polysilicon layer. After removing portions of the second dielectric layer, the first doped polysilicon layer, the silicon nitride layer and the first dielectric layer by a first photoresist layer, a contact hole is formed. A second doped polysilicon layer is formed over the second dielectric layer, and the contact hole is thus filled by the second doped polysilicon layer. Thereafter, portions of the second doped polysilicon layer and the second dielectric layer are removed using a second photoresist layer as a mask, thereby exposing the first doped polysilicon layer. A third dielectric layer is formed on the second doped polysilicon layer, the first polysilicon layer, and on the sidewalls of the second dielectric layer. After etching back the third dielectric layer, a third doped polysilicon layer is formed. Furthe…