CN201089805Y

CN201089805Y - Crucible for preparing vertical pulling silicon monocrystal

Info

Publication number: CN201089805Y
Application number: CNU2007201734830U
Authority: CN
Inventors: 吴志强; 戴小林; 崔彬; 姜舰
Original assignee: Beijing General Research Institute for Non Ferrous Metals; Grinm Semiconductor Materials Co Ltd
Current assignee: You Yan Semi Materials Co., Ltd.
Priority date: 2007-09-29
Filing date: 2007-09-29
Publication date: 2008-07-23
Anticipated expiration: 2017-09-29

Abstract

The utility model provides a crucible used in preparing direct-pulling silicon single crystal and adopted in a silicon single crystal growth method named as Czochralski (or direct pulling) method, wherein silicon crystal grows inside a growth chamber. The crucible comprises a crucible upper part and a crucible bottom connected with a lower shaft, wherein the inside of the crucible upper part is equally divided into a plurality of assembly reinforcing rings along the axle center of the crucible; moreover, another outer ring is covered outside the reinforcing rings. The utility model has the advantages that: the crucible has light weight, easy installation and a service life equivalent to that of a crucible adopting the prior structure.

Description

A kind of czochralski silicon monocrystal preparation crucible

Technical field

The present invention relates to the equipment that is used to make unicircuit and other electron component semiconductor grade silicon single crystal.Particularly relate to heat supply parts in a kind of thermal field of produce single crystal silicon rod, promptly be used to support the crucible of the quartzy crucible that polycrystalline silicon material is housed.

Semiconductor silicon single crystal body about 85% is all with cutting krousky (Czochralski) manufactured.In this method, polysilicon is put in the quartzy crucible, heat fused then, will melt silicon and slightly do cooling, give certain condensate depression, the silicon single crystal of a particular crystal orientation (being called seed crystal) is contacted with melt silicon, and temperature by adjusting melt and the seed crystal pulling speed that makes progress is when making seed body grow up to the close-target diameter, improve pulling speed, make the nearly permanent growth in thickness of single crystal.In the last stage of process of growth, the interior silicon melt not completely dissolve as yet of crucible this moment, by the heat supplied that increases the crystalline pulling speed and adjust crystal diameter is reduced to form a tail shape cone gradually to crucible, when sharp enough hour of cone, crystal will break away from melt, thereby finishes the crystalline process of growth.In brief, the present invention relates to a kind of growth technique of cutting krousky (vertical pulling) method silicon crystal rod that is called, this crystal bar is a circular object, has a central shaft, a seed crystal end cone and a tail end cone are the right cylinders of near constant diameter between these two cones.

Czochralski silicon monocrystal roughly is divided into so several stages during fabrication: the dress polycrystal, find time, growth, equal diameter growth, the growth of afterbody crystalline, the crystal cooling of unmelted polycrystalline silicon, neck and shoulder, wherein most of process is an endothermic process, that is to say to want outside heat supplied.A main heating element (graphite system) is generally arranged in the single crystal growing furnace, and direct current on its two ends lead to produces heat.Heating element is in the outside of heat-absorbing body, that is to say, heat is ecto-entad conduction (radially).Increasing (Ф 200mm along with the silicon single-crystal diameter, Ф 300mm, more than the Ф 300mm), the size of thermal field of single crystal furnace becomes increasing, the polysilicon weight that every stove is packed into is from original 45KG 100-300KG till now, correspondingly, the weight of plumbago crucible has also increased greatly, and people can not install safely and take off it.Because material increases phenomenon appears damaging in the junction of last crucible at the bottom of the crucible, therefore alleviate it weight, gain in strength and conveniently be mounted to the task of top priority.

Summary of the invention

The purpose of this utility model provides a kind of czochralski silicon monocrystal preparation crucible, and this crucible is in light weight, should install, and the crucible of its work-ing life and original structure is suitable.

For achieving the above object the utility model by the following technical solutions: this czochralski silicon monocrystal preparation crucible, it comprises: crucible top, with at the bottom of the crucible that lower shaft is connected, the inboard on described crucible top is along the branch polylith assembly unit stiffening rings such as axle center of crucible, and another outer ring is enclosed within outside the stiffening ring.

But the crucible materials used in the utility model has graphite, wherein, can adopt the isometrical pressure graphite of purifying, carbon fiber, molybdenum sheet etc. at the bottom of stiffening ring or the crucible etc., and these material markets are on sale.The structure formation of stiffening ring can be entity bucket or grid bucket (being called basket), and top hole can be dimetric, and rectangular also can be that justify or oval.

This reality goes out novel advantage: this crucible is in light weight, should install, and the crucible of its work-ing life and original structure is suitable.

Description of drawings

Fig. 1: the main sectional view of cutting the single crystal growing furnace of krousky (vertical pulling) manufactured silicon single-crystal

Fig. 2: the formation of the existing crucible among Fig. 1 and with the front view of the installation site of quartzy pot, lower shaft

Fig. 3 a: a kind of crucible front view of the present utility model

Fig. 3 b: Fig. 3 a vertical view

Fig. 4: the stiffening ring among Fig. 3 a is at the stereographic map of two timesharing such as grade

Fig. 5 a: a kind of barrel knot composition

Fig. 5 b: the structural representation of another kind of bucket

Embodiment

Among Fig. 1, single crystal growing furnace comprises: 1 is seed crystal (a kind of silicon single crystal of particular crystal orientation), and 13 is silicon melt, 16 is quartzy crucible, and 14 is the graphite crucible, and 19 is the melted silicon surface, 3 is silicon single crystal bar, and 4 is upper cover plate, and 20 is heat shielding, 8 is the stove tube, and 9 are tail gas outlet, 5 lagging materials, 10 are insulation down, and 11 is lower shaft, and 12 are end insulation, 6 is thermometer hole, and 7 is main heating element.

Among Fig. 2, the 16th, quartzy crucible, it is positioned at plumbago crucible, and the 22nd, crucible top; The 23rd, at the bottom of the crucible, be connected with lower shaft 24 at the bottom of the crucible.Except that quartzy crucible, other parts all are to be made by graphite.

Among Fig. 3 a, Fig. 3 b, 23 is that the inboard on described crucible top is along the branch polylith assembly unit stiffening rings 30 such as axle center of crucible with at the bottom of the crucible that lower shaft is connected, and another outer ring 29 is enclosed within outside the stiffening ring 30.

Parts 29 and parts 30 can be to be made by carbon fibre material, and their structure can be (seeing Fig. 5 a), the bucket of grid also can be arranged, as basket (seeing Fig. 5 b) of whole drum shape.

Parts 23 also can be made with carbon fibre material.And parts 30 can be divided into the 2-12 five equilibrium along the axle center of crucible, see Fig. 4 (two timesharing such as grade).

Operation steps: earlier quartzy crucible is put into graphite crucible supporting apparatus, polycrystalline silicon material is put into quartzy crucible, load onto the seed crystal of particular crystal orientation, the furnace chamber that closes, and vacuumize, heating makes the silicon fusing then, after silicon melted fully, the temperature of progressively reducing to molten silicon was near the fusing point of silicon.Allow quartzy crucible and seed crystal reverse rotation, silicon seed is slowly descended, and contact with molten silicon, upwards promote seed crystal with certain speed then, the purpose of this process mainly is to eliminate the dislocation defects that forms because of thermal shocking in the seed crystal.When treating that seed crystal rises to certain-length, pulling speed is slowed down, slightly reduce the temperature of melt simultaneously, make the seed crystal enlarged diameter, when the seed crystal diameter increases to than low approximately 10 millimeter of aimed dia, increase pulling speed, make crystal be close to the equal diameter growth.Store the silicon material not for a long time in quartzy crucible, improve pulling speed again, suitably increase the power of heating simultaneously, make crystal diameter be changed to a back taper, when boring point enough hour, it can break away from silicon melt, and at this moment the crystalline process of growth finishes.When being cooled to be close to room temperature, crystal can be taken off in crystal.

Claims

1. crucible is used in czochralski silicon monocrystal preparation, and it comprises: crucible top, with at the bottom of the crucible that lower shaft is connected, it is characterized in that: the inboard on described crucible top is along the branch polylith assembly unit stiffening rings such as axle center of crucible, and another outer ring is enclosed within outside the stiffening ring.

2. crucible is used in a kind of czochralski silicon monocrystal preparation according to claim 1, and it is characterized in that: described five equilibrium polylith assembly unit stiffening ring is the 2-12 five equilibrium.