Semiconductor device manufacturing: process – Formation of electrically isolated lateral semiconductive... – Grooved and refilled with deposited dielectric material
Reexamination Certificate
2000-02-24
2001-08-07
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Formation of electrically isolated lateral semiconductive...
Grooved and refilled with deposited dielectric material
C438S221000
Reexamination Certificate
active
06271100
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to semiconductor device manufacturing, and in particular to a method of reducing stress in an isolation trench which includes an anneal step that is performed under rapid thermal conditions at a relatively high temperature and in the presence of an atmosphere comprising hydrogen.
BACKGROUND OF THE INVENTION
In the manufacturing of semiconductor devices, it is well known to form isolation regions that electrically isolate the various active regions present within the device from each other. One method of electrically isolating the active device regions is to form a trench isolation region between adjacent devices. Such prior art trench isolation regions typically comprise a trench that is formed within the substrate and filled with a dielectric material such as SiO
2
.
Three types of trench isolation regions are known: including shallow trenches (trenches whose depth is less than about 1 &mgr;m), moderate trenches (trenches whose depth is from about 1 to about 3 &mgr;m), and deep trenches (trenches whose depth is greater than 3 &mgr;m).
Shallow trench isolation (STI) regions are the choice of device isolation used in bipolar technologies. Despite this, the presence of STI regions in bipolar devices has some drawbacks associated therewith. In particular, it is well known that bipolar pipe yield can be affected by dislocations originating at the corner of the STI region. This problem has been shown to be caused by the stress in the isolation trench due to over oxidation during the semiconductor processing.
Several approaches have been attempted in order to reduce the stress problem in the STI region. Some of the more common prior art attempts for reducing stress include: reducing the amount of oxidation in the trench as well as reducing the level of Si interstitials at the base of the STI using a sink such as C implants. Others have shown that stress in the trench may be reduced by relaxation of the tetraethylorthosilicate (TEOS) trench dielectric material thru high temperature anneals.
To date, no effective method is known which is capable of substantially reducing the stress in the trench isolation region. As such, there is a continued need for developing a new and improved method that can adequately reduce the stress of the trench isolation region caused by over oxidation during the manufacturing of the semiconductor device. Such a method would represent a significant advancement in the art since it would lead to increase bipolar pipe yield.
SUMMARY OF THE INVENTION
The present invention relates to a method of substantially reducing stress in an isolation trench (shallow, moderate or deep) by using an anneal step that is performed under rapid thermal conditions at relatively high temperatures and in an atmosphere comprising hydrogen. Specifically, the method of the present invention comprises the steps of:
(a) forming at least one trench in a substrate, said substrate having a surface;
(b) filling the at least one trench with a trench dielectric material;
(c) planarizing the filled trench stopping on said surface of said substrate; and
(d) subjecting the planarized trench to an anneal step, said anneal step being carried out under rapid thermal conditions at a temperature of about 800° C. or above and in the presence of an atmosphere comprising hydrogen.
REFERENCES:
patent: 5516721 (1996-05-01), Galli et al.
patent: 5858858 (1999-01-01), Park et al.
patent: 5867420 (1999-02-01), Alsmeier
patent: 5893760 (1999-04-01), Mikata et al.
patent: 5910018 (1999-06-01), Jang
patent: 5913125 (1999-06-01), Brouillette et al.
patent: 5933748 (1999-08-01), Chou et al.
patent: 6084271 (2000-07-01), Yu et al.
patent: 6084276 (2000-07-01), Gambino et al.
patent: 2256967 A (1992-12-01), None
Ballantine Arne Watson
Coolbaugh Douglas Duane
Gilbert Jeffrey D.
Huang Quoc
International Business Machines - Corporation
Nelms David
Sabo William D.
Scully Scott Murphy & Presser
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