Plasma etching uniformity control

Details Plasma etching uniformity control Plasma etching uniformity control

2002-02-13

2004-05-18

Goudreau, George A. (Department: 1763)

Semiconductor device manufacturing: process

Chemical etching

Vapor phase etching

C216S067000

Reexamination Certificate

active

06737358

ABSTRACT:

TECHNICAL FIELD
This invention relates to plasma etching uniformity control.
BACKGROUND
Plasma etching is used, e.g., in the fabrication of integrated circuits to produce high-resolution patterns in a semiconductor (e.g., silicon) wafer. The wafer is placed in a chamber in which electrons are accelerated by radio frequency (RF) or microwave electric fields. The electrons collide with other molecules to produce ions, neutral radicals, and more electrons. Between the plasma and the wafer surface layer, an electron-free space-charge region, called a “sheath”, is formed, and ions are accelerated toward the wafer surface when entering the sheath. The accelerated ions bombard the wafer surface with high energies and chemically etch areas of the wafer that are exposed to the plasma. The areas exposed are in patterns defined by a resist placed on the wafer surface using lithographic methods.
In a typical plasma etching process, the etch rate near the center of the wafer is often greater than the etch rate in peripheral regions of the wafer, which can lead to uneven etch depths across the wafer. To alleviate this problem, wafers are sometimes provided with a stop layer at the desired etch depth. The stop layer is made of a material that is etched at a lower rate compared to the wafer surface material. As a result, when the central portions etch to the stop layer, etching can be continued until the peripheral regions etch to the stop layer.


REFERENCES:
patent: 4578559 (1986-03-01), Hijikata et al.
patent: 5053104 (1991-10-01), Babu et al.
patent: 5843847 (1998-12-01), Pu et al.
patent: 6287981 (2001-09-01), Kim et al.
patent: 6290806 (2001-09-01), Donohoe
patent: 6291793 (2001-09-01), Qian et al.
patent: 6436812 (2002-08-01), Lee
patent: 2002/0132488 (2002-09-01), Nollan
patent: 61-171127 (1986-08-01), None
“Implementation of Tungsten Metallization In Multilevel Interconnection Technologies”; IEEE Trans, on Semiconductor Mfg; vol. 3, No. 4; (Nov. 1990); Riley et al.; pp. 150-157.*
“X-Ray Mask Fabrication Technology for 0.1 &mgr;m Very Large Scale Integrated Circuits”; J. Vac Sci.; B; 14(6); (Dec. 1996); Oda et al.; pp. 4366-4370.

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