US 6,551,874 B2 · Self-aligned STI process using nitride hard mask

Abstract

A nitride hard mask (230) is used to isolate active areas of a DRAM cell. The shallow trench isolation (STI) method includes forming memory cells comprising deep trenches (216) on a semiconductor wafer (200). The memory cell deep trenches (216) are separated from active areas (212) by a region of substrate (212). A nitride hard mask (230) is formed over the semiconductor wafer (200). The wafer (200) is patterned with the nitride hard mask (230), and the wafer (200) is etched to remove the region of substrate (212) between the deep trenches and active areas to provide shallow trench isolation. An etch chemistry selective to the nitride hard mask (230) is used.

Claims21

Dependent claims

A method of forming a memory device, the method comprising:

forming memory cells on a semiconductor wafer, each memory cell including a deep trench proximate an active area, wherein at least two adjacent deep trenches define a semiconductor region therebetween;
forming a nitride hard mask over the semiconductor region and the at least two deep trenches;
and
patterning the nitride hard mask and etching to remove the semiconductor region, wherein the nitride hard mask prevents the deep trenches from being etched during the etching step.

1 more element

Dependencies are inferred from the claim text.

Facts

Application

09/888,287Filed 22 Jun 2001

Published

US 2003/0045051 A16 Mar 2003

Granted

22 Apr 2003

Term ends

Not estimatedThe source records don’t support an estimate.

Classification5 codes

H10B 12/038
Making the capacitor or connections thereto: the capacitor being in a trench in the substrate
H10W 10/014
Of isolation regions comprising dielectric materials: using trench refilling with dielectric materials, e.g. shallow trench isolations
H10W 10/17
Isolation regions comprising dielectric materials: formed using trench refilling with dielectric materials, e.g. shallow trench isolations
H10B
Electronic memory devices

Self-aligned STI process using nitride hard mask

Life of this patent

Self-aligned STI process using nitride hard mask

Life of this patent

Abstract

Claims21