Technique of bottle-shaped deep trench formation
US6232171A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Jun 8, 1999 |
| Grant date | May 15, 2001 |
| Priority date | — |
| Expiry date | Jun 8, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/047
Abstract
A method for fabricating deep-submicron vertically arranged capacitors is disclosed which allows the capacitor to enjoy an enhanced sidewall surface so as to attain a capacitance of 40 pF or more. The method comprises the steps of: (a) forming an elongated trench into an active region of a substrate, the elongated trench having a sidewall defining the trench inside the substrate; (b) forming a oxide filler layer which fills the deep trench; (c) etching the oxide filler layer to a predetermined depth, to reveal an upper portion of the sidewall above the predetermined depth; (d) forming a nitride sidewall spacer cover the upper portion of the sidewall; (e) etching away the oxide filler layer to reveal the lower portion of the sidewall; (f) using the sidewall spacer as a mask to either selectively etch away the lower portion of the sidewall or cause the lower portion of the sidewall to be subject to a chemical reaction so that the lower portion of the sidewall can be etched away and thus causing the trench width in the lower portion to be enlarged; and (g) removing the chemically altered lower portion of the sidewall if it is not already removed, to form a bottle-shaped deep trench ha…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.