Single-crystal – oriented-crystal – and epitaxy growth processes; – Apparatus – For crystallization from liquid or supercritical state
Reexamination Certificate
1999-06-21
2001-08-07
Hiteshew, Felisa (Department: 1765)
Single-crystal, oriented-crystal, and epitaxy growth processes;
Apparatus
For crystallization from liquid or supercritical state
C117S014000, C117S015000, C117S911000
Reexamination Certificate
active
06270575
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus and a method of manufacturing a crystal, especially an apparatus and a method which are effective to increase the productivity of a crystal.
2. Description of the Prior Art
Czochralski Method (hereinafter referred to as “CZ Method”) is known as a manufacturing method of a single crystal of silicon. In the CZ Method, a seed crystal is dipped on the melt which is formed by melting the polycrystalline ingredient, and the seed is lifted to growth the crystal thereunder.
In the CZ Method, crystal defect called “dislocation” is generated at the dipped portion. Such dislocation causes quality deterioration. Therefore, a contraction process called “necking” has been performed to form the neck having predetermined length. As a result, the dislocation can be prevented from entering the crystal.
During the necking, however, the slender neck portion which has been contracted can be broken due to its slender diameter. In this manner, when the break is caused during necking, the necked portion must be melted again, and it is necessary to do the pulling operation all over again.
Additionally, in the case of melting the neck portion, the temperature of the melt must be raise. As a result, a suitable thermal environment for the crystal growth is lost. Therefore, temperature adjustment is necessary when the pulling operation is done over from start.
However, this temperature adjustment is a complicated operation and it takes much time. A smooth crystal manufacturing cannot be achieved by having adjusted the temperature and melted the neck portion whenever the necking fails. This causes the productivity of crystal to reduce.
SUMMARY OF THE INVENTION
The present invention is constructed in order to provide an apparatus and a method which are effective to increase the productivity of a crystal.
To achieve this object, in the present invention, a broken part is dipped on the melt within ten seconds and afterwards pulling operation is restarted. The reason for dipping the broken part within ten seconds is to suppress the temperature difference between the broken part and the melt to be able to exist within the range of the allowance. The permissible level of the temperature difference is determined based on whether the dislocation is generated or not. If the dislocation is not generated when the broken part is dipped on the melt, the pulling operation can be restarted immediately and the productivity of the crystal increases.
REFERENCES:
patent: 5582642 (1996-12-01), Korb et al.
patent: 5948160 (1999-09-01), Sakurada
Hukuda Nobuyuki
Kamogawa Makoto
Kurosaka Shoei
Tomioka Junsuke
Hiteshew Felisa
Komatsu Electronic Metals Co. Ltd.
Welsh & Katz Ltd.
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