CN106222740A - A kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting - Google Patents

A kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting Download PDF

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Publication number
CN106222740A
CN106222740A CN201610695211.0A CN201610695211A CN106222740A CN 106222740 A CN106222740 A CN 106222740A CN 201610695211 A CN201610695211 A CN 201610695211A CN 106222740 A CN106222740 A CN 106222740A
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polycrystalline silicon
heater
silicon ingot
crucible
heating
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贺鹏
刘波波
蔺文
吴增伟
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XI'AN HUAJING ELECTRONIC TECHNOLOGY Co Ltd
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XI'AN HUAJING ELECTRONIC TECHNOLOGY Co Ltd
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Priority to CN201610695211.0A priority Critical patent/CN106222740A/en
Publication of CN106222740A publication Critical patent/CN106222740A/en
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    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B28/00—Production of homogeneous polycrystalline material with defined structure
    • C30B28/04—Production of homogeneous polycrystalline material with defined structure from liquids
    • C30B28/06—Production of homogeneous polycrystalline material with defined structure from liquids by normal freezing or freezing under temperature gradient
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/0009—Demolition agents based on cementitous or like materials
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
    • C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
    • C04B41/5053—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials non-oxide ceramics
    • C04B41/5062—Borides, Nitrides or Silicides
    • C04B41/5064—Boron nitride
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
    • C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
    • C04B41/81—Coating or impregnation
    • C04B41/85—Coating or impregnation with inorganic materials
    • C04B41/87—Ceramics
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/06—Silicon

Abstract

The invention discloses a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, including step: one, prepared by crucible bottom coating: coating spraying liquid is prepared, sprayed and dry；Two, charging: load silicon material in the crucible of band base coat, and the crucible of built-in silicon material is loaded in polycrystalline silicon ingot or purifying furnace；Polycrystalline silicon ingot or purifying furnace is built with hexahedro heater；Hexahedro heater includes bottom heater, top heater and four side heater；Three, preheating；Four, fusing, process is as follows: 401, heat up for the first time；402, second time heats up；403, subsequent melting；Five, long crystalline substance；Six, anneal and cool down.The present invention is reasonable in design and realization is easy, using effect is good, by coating one layer of base coat with boron nitride as primary raw material in crucible bottom, and use hexahedro heater to heat, can effectively reduce crucible bottom oxygen content, and can effectively reduce the Hard Inclusion of ingot casting finished product, improve the quality of ingot casting finished product.

Description

A kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting
Technical field
The invention belongs to polycrystalline silicon ingot casting technical field, especially relate to a kind of reduce oxygen content bottom polycrystalline silicon ingot casting Polycrystalline silicon ingot casting method.
Background technology
Photovoltaic generation is one of currently the most important clean energy resource, has great development potentiality.Restriction photovoltaic industry is sent out The key factor of exhibition, is on the one hand that electricity conversion is low, is on the other hand high expensive.Photovoltaic silicon wafer is to produce solar-electricity Pond and the stock of assembly, for produce photovoltaic silicon wafer polysilicon purity must (i.e. non-silicon impurity always contains more than 6N level Amount is at below 1ppm), otherwise the performance of photovoltaic cell is by by the biggest negative effect.In recent years, polysilicon chip production technology Having had marked improvement, polycrystalline cast ingot technology arrives from G4 (each silicon ingot weighs about 270 kilograms, can cut 4 × 4=16 silicon side) progress G5 (5 × 5=25 silicon side) is the most progressive to G6 (6 × 6=36 silicon side).Further, the unit of produced polycrystalline silicon ingot casting Volume incrementally increases, and yield rate increases, and the manufacturing cost of unit volume polycrystalline silicon ingot casting gradually reduces.
In actual production process, during solar energy polycrystalline silicon ingot casting, need to use silica crucible to load silicon material, and by silicon material throw After entering silica crucible, the most also need preheated, fusing (also referred to as melt), long brilliant (also referred to as directional solidification crystallization), annealing, The steps such as cooling, just can complete polycrystalline silicon ingot casting process.At present, during solar energy polycrystalline silicon ingot casting, the crucible spray used Si is used during painting3N4Material is as sprayed on material, but because of Si3N4The heat conductivility of material itself is poor, unstability etc. Feature, easily forms the oxygen content bottom Hard Inclusion, and ingot casting finished product during making ingot casting higher, has the quality of product very Big impact.Meanwhile, Si3N4Although material can be effectively isolated silicon liquid and crucible reaction, but Si3N4After reacting with silicon liquid Form red sector, be easily introduced impurity Si3N4And form Hard Inclusion, the quality of ingot casting finished product is affected the biggest.
It addition, the heater that existing polycrystalline silicon ingot or purifying furnace is used generally is five heating arrangements, i.e. on the top of crucible Portion and four side-wall outer side are provided with heater, and this five mode of heatings carry out heat radiation, melting efficiency from top to down Relatively low, simultaneously crucible bottom gas be difficult to get rid of, make the oxygen content bottom ingot casting finished product higher.
Summary of the invention
The technical problem to be solved is for above-mentioned deficiency of the prior art, it is provided that a kind of reduction polycrystalline The polycrystalline silicon ingot casting method of oxygen content bottom silicon ingot casting, its method step is simple, reasonable in design and realizes easy, using effect Good, by coating one layer of base coat with boron nitride as primary raw material in crucible bottom, and use hexahedro heater to carry out Heating, can effectively reduce crucible bottom oxygen content, and can effectively reduce the Hard Inclusion of ingot casting finished product, improves the matter of ingot casting finished product Amount.
For solving above-mentioned technical problem, the technical solution used in the present invention is: bottom a kind of reduction polycrystalline silicon ingot casting, oxygen contains The method of amount, it is characterised in that the method comprises the following steps:
Prepared by step one, crucible bottom coating, process is as follows:
Step 101, coating spraying liquid are prepared: by organic cementing agent, deionized water and boron nitride by 1: (2～2.5): (0.8 ～1.2) mass ratio uniformly mix, obtain coating spraying liquid；
Step 102, spraying: use spraying equipment by the even application of coating spraying liquid described in step 101 to crucible On bottom surface, portion, 1m in described crucible inner bottom surface2In region, in the described coating spraying liquid of spraying, the quality of contained boron nitride is 100g～200g；
Described crucible is quartz crucible for polycrystalline ingot furnace；
Step 103, drying: crucible described in step 102 is placed horizontally in drying plant, and uses described drying to set Standby and under 80 DEG C～100 DEG C of temperature conditionss, the described coating spraying liquid being sprayed in crucible inner bottom surface is dried, obtain Obtain base coat；
Step 2, charging: in step one, in the crucible of band base coat, load silicon material, and the crucible of built-in silicon material is filled Enter in polycrystalline silicon ingot or purifying furnace；
Polycrystalline silicon ingot or purifying furnace is built with hexahedro heater；Described hexahedro heater includes the end being laid in below crucible Portion's heater, the sidepiece being laid in the top heater above crucible and four four side-wall outer side being laid in crucible respectively add Hot device, described crucible be cube crucible and its be level lay, described top heater and bottom heater are all in horizontal cloth If, four described side heater all in vertically to laying；
Step 3, preheating: top heater, bottom heater and four described side heater are all opened, and uses The silicon material being loaded in crucible is preheated by polycrystalline silicon ingot or purifying furnace, and the heating-up temperature of polycrystalline silicon ingot or purifying furnace is stepped up to T1；Preheating time is 4h～6h, wherein T1=1125 DEG C～1285 DEG C；
Step 4, fusing, process is as follows:
Step 401, for the first time intensification: use polycrystalline silicon ingot or purifying furnace that the silicon material being loaded in crucible is melted, fusing temperature Degree is stepped up to T2 by T1；Wherein T2=1350 DEG C～1400 DEG C；
Step 402, second time heat up: use polycrystalline silicon ingot or purifying furnace to continue to melt the silicon material being loaded in crucible, molten Change temperature to be stepped up to T3 by T2；Wherein T3=1540 DEG C～1560 DEG C；
Step 403, subsequent melting: after the silicon material in crucible all melts, by the heating-up temperature control of polycrystalline silicon ingot or purifying furnace System is at T3, and the heating power of the most described top heater and four described side heater all begins to decline, and treats described top After the heating power of heater and four described side heater all stops decline and persistent period t, melt process completes；Wherein T=20min～40min；
Top heater described in step 401, step 402 and step 403 and four described side heater are in out Opening state, described bottom heater is closed；
Step 5, long crystalline substance: carry out after the heating-up temperature of polycrystalline silicon ingot or purifying furnace is gradually decreased to polysilicon crystal temperature by T3 Directional solidification, until completing long brilliant process；Wherein polysilicon crystal temperature is 1420 DEG C～1440 DEG C；
Step 6, anneal and cool down: after long brilliant process completes in step 5, anneal and cool down, and obtaining and be processed into The described polycrystalline silicon ingot casting of type.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: institute in step 101 Stating organic binder bond is phenolic aldehyde-neoprene adhesive, epoxy adhesive, Instant adhesive, acrylic acid adhesive, polyvinyl alcohol Adhesive, Polyvinyl acetate adhesive, AE SGA, butvar adhesive stick or glass cement；
Described boron nitride is hexagonal boron nitride.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: pre-in step 3 In thermal process neutralization procedure 401 in hexahedro heating fusion process, top heater, bottom heater and four described in synchronization The heating power of described side heater is the most identical；In step 402, five are heated in fusion process neutralization procedures 403 subsequent melting During, top heater described in synchronization is the most identical with the heating power of four described side heater.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: pre-in step 3 In thermal process, synchronize progressively to rise by the heating power of top heater, bottom heater and four described side heater Height, and the heating power of top heater, bottom heater and four described side heater is all stepped up to P1, wherein P1=50kW～100kW；
In step 401 in hexahedro heating fusion process, described top heater, bottom heater and four described sidepieces add The heating power of hot device is P1；
In step 402 in five heating fusion processes, described top heater and the heating of four described side heater Power is P1；
In step 403 subsequent melting during, after the silicon material in crucible all melts, described top heater and four The heating power of described side heater synchronizes progressively to decline, and becomes the heating power of top heater or side heater Change situation is observed, and when the heating power of top heater or side heater drops to P2, keeps P2 constant and continues After time t, melt process completes；Wherein, P2=25kW～45kW.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: institute in step 2 State top heater, bottom heater and four described side heater to be all connected with heating power adjusting means；
In step 3 in warm, use heating power adjusting means to top heater, bottom heater and four The heating power of described side heater synchronizes to be stepped up.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: described top adds Hot device is connected with top firing power supply by the first electrode, and four described side heater are all heated with sidepiece by the second electrode Power supply connects, and described bottom heater is connected with bottom-heated power supply by the 3rd electrode；Described top firing power supply, sidepiece add Thermoelectric generator and bottom-heated power supply are all connected with heating power adjusting means, and described heating power adjusting means is to top firing The PCU Power Conditioning Unit that the output of power supply, sidepiece heating power supply and bottom-heated power supply is adjusted respectively.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: enter in step 4 During row fusing, process is as follows:
1st step, insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace at T1, and it is incubated 0.4h～0.6h；
2nd step to the 5th step, heat up and pressurize: by first to rear point of four step by the heating-up temperature of polycrystalline silicon ingot or purifying furnace by T1 by Gradually being promoted to T4, the heating-up time is 0.4h～0.6h；Temperature-rise period is filled with in polycrystalline silicon ingot or purifying furnace noble gas and will be many Crystal silicon ingot furnace internal gas pressure steps up to Q1；Wherein, T4=1190 DEG C～1325 DEG C, Q1=550mbar～650mbar；
6th step, for the first time intensification and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace is gradually promoted to by T4 T5 and intensification Time is 3.5h～4.5h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace internal gas pressure is maintained at Q1；Wherein, T5=1440 DEG C～1460 ℃；
7th step: second time heats up and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace is gradually promoted to T6 and intensification by T5 Time is 3.5h～4.5h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace internal gas pressure is maintained at Q1；Wherein, T6=1490 DEG C～1510 ℃；
8th step, third time heat up and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace is gradually promoted to T3 and intensification by T6 Time is 3.5h～4.5h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace internal gas pressure is maintained at Q1；
9th step, insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace at T3, and it is incubated 3.5h～4.5h；Insulating process In, described polycrystalline silicon ingot or purifying furnace internal gas pressure is maintained at Q1；
10th step, persistently insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace at T3, and be incubated 4h～8h, until earthenware Silicon material in crucible all melts；In insulating process, described polycrystalline silicon ingot or purifying furnace internal gas pressure is maintained at Q1.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: institute in step 102 Stating spraying equipment is liquid spray gun, and drying plant described in step 103 is baking oven.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: described baking oven bag Include the vertical heating of casing, the horizontal heater being laid in crucible bottom and four four side-wall outer side being laid in crucible respectively Device, four described vertical heaters are respectively positioned on above horizontal heater, described horizontal heater are provided with for crucible placement Graphite cushion block.
A kind of above-mentioned polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, is characterized in that: enter in step 102 During row spraying, 1m in described crucible inner bottom surface2In region, in the described coating spraying liquid of spraying, the quality of contained boron nitride is 100g～150g；
When step 103 is dried, first use described drying plant that crucible is heated to 80 DEG C～100 DEG C, then carry out It is incubated till the described coating spraying liquid being sprayed in crucible inner bottom surface is dried.
The present invention compared with prior art has the advantage that
1, method step is simple, reasonable in design and realizes conveniently, it is easy to grasping, input cost is relatively low.
2, the coating material used is by organic cementing agent, deionized water and boron nitride, and cost is relatively low and preparation is easy.
3, the coating material used, using boron nitride as primary raw material, can effectively increase crucible bottom heat-conducting effect, and Can reduce crucible bottom oxygen content, Simultaneous Stabilization is good, is not easily formed Hard Inclusion during ingot casting, and ingot casting finished product can be effectively ensured Quality.
4, the coating material used can effectively reduce the cost of polycrystalline silicon ingot casting, during due to boron originally as polycrystalline silicon ingot casting A kind of adulterant used, but the cost of pure boron is at a relatively high；And prepare after using the coating material coating disclosed in the present invention During polysilicon ingot crucible base coat, the doping of pure boron can be reduced, even avoid adding pure boron, it is thus possible to effectively drop Low polycrystalline silicon ingot casting cost.
5, the painting method used is reasonable in design and realization is easy, using effect is good, can be easy, quickly in crucible bottom Making one layer of base coat, and the base coat quality made is good, coating procedure is easily controllable.Meanwhile, the baking used Stem structure is reasonable in design and cost is relatively low, using effect goods, and energy is easy, be rapidly completed the drying course of crucible bottom coating, and And heats is good, crucible bottom uniform coating thickness and quality that machine-shaping can be effectively ensured are good.
6, the hexahedro heater simple in construction that used, reasonable in design and input cost is relatively low, is laid in polysilicon casting In ingot stove, and it is provided with the temperature-detecting device that the heating-up temperature to hexahedro heater detects in real time, temperature control process Easily controllable and temperature detection result intuitive display, can be to the heating temperature of top heater, bottom heater and side heater Degree detects the most in real time.
7, the hexahedro heater used is installed and is laid simplicity, and to existing polycrystalline silicon ingot or purifying furnace inner heating device Change less, only need to set up bottom heater below crucible, and bottom heater is fixed on and is supported in crucible bottom DS block on, fixing simplicity.
8, in the hexahedro heater used, top heater, bottom heater and side heater use the most independent Power supply, top heater, bottom heater and side heater can individually control and the heating power of three can separate Individually be controlled, now control mode have the advantage that first, more energy-conservation, as sidepiece can be reduced in crystal growing stage The heat time heating time of heater, thus reach to reduce the purpose of h eating power, can effectively reduce unit interval inner cooling water band simultaneously The heat walked, thus indirectly decrease the load of power refrigeration equipment；The second, thermal field can be better controled over, owing to top adds Hot device, bottom heater and side heater can individually control, and simplicity can realize top heater, bottom heater and side The purpose of portion's heater separately heating, it is thus possible to reach effectively to control the purpose of thermal field；3rd, crystal growing process is had The biggest improvement result, is conducive to being internally formed vertical gradient thermal field evenly at polycrystalline silicon ingot or purifying furnace, thus preferably controls The long brilliant speed of system so that long crystal boundary face is more mild, thus reduces the unfavorable factor such as shade, red sector, and heats is more preferably；The Four, can effectively alleviate the load of carrying on main line, effectively reduce the electric current superposition amount on main line, thus reduce line load Amount, has certain protective effect for bus and switchgear house；5th, the service life of internal thermal field can be extended, as on long brilliant rank After section reduces the heat time heating time of side heater, can effectively reduce the side heater thermo-contact time to adjacent warming plate, from And extend the service life of internal insulation plate and thermal field.
9, the hexahedro heater used uses easy and simple to handle, is added hexahedro heater by temperature-detecting device Hot temperature detects and by detected temperature information synchronous driving in real time to main controller, then by main controller to being laid in polycrystalline Hexahedro heater in silicon ingot furnace is controlled.
10, the hexahedro heater using effect used is good and practical value high, changes existing polycrystalline silicon ingot or purifying furnace Use five heating arrangements to carry out thermal-radiating mode of heating from top to down, after setting up bottom heater below crucible, formed One from upper and lower, left and right, front and rear six direction hexahedro heating arrangement that silicon material in crucible is heated, and control letter Just, temperature control process is easily controllable, can not only improve melting efficiency, and can be effectively improved the heating of crucible bottom during melt Speed, beneficially crucible bottom gas are discharged, it is thus possible to effectively reduce the bottom oxygen content of ingot casting finished product, can significantly improve ingot casting The yield rate of finished product and quality.Thus, use hexahedro heater that silicon material in crucible is heated, existing polysilicon can be solved The melting efficiency that ingot furnace is used five heating arrangements to exist is relatively low, crucible bottom gas is difficult to bottom eliminating, ingot casting finished product The problem such as oxygen content is higher.
11, during melt, the heating power of top heater, bottom heater and side heater controls easy and real Now facilitating, in fusion process, after the silicon material in crucible all melts, the heating-up temperature controlling polycrystalline silicon ingot or purifying furnace keeps not Become, and the time dependent curve of heating power (i.e. power curve) of polycrystalline silicon ingot or purifying furnace is observed；Wherein, crucible is treated After interior silicon material all melts, the power curve of polycrystalline silicon ingot or purifying furnace begins to decline, and treats under the power curve of polycrystalline silicon ingot or purifying furnace After dropping and walking flat 20min～40min, melt process completes, and carries out crystal growing stage afterwards.In actual mechanical process, by observation Power curve just can accurately determine the time point that melt process completes, and is i.e. switched to the switching time of crystal growing stage by the melting stage Point.Practical operation is easy, and realizes conveniently, and energy accurate assurance is switched to the switching time of crystal growing stage by the melting stage.The most just Being to say, the present invention stablizes ingot casting melt curve by extending the melt time, cuts after power curve walks flat 20min～40min again Enter crystal growing stage, thus can accurately be melted to the switching time of crystal growing stage, stopped due to melt deficiency of time or molten simultaneously Polycrystalline silicon ingot casting Quality Down that material overlong time causes, the problem such as cost increase.Further, use the present invention to polycrystalline silicon ingot casting During after melt carries out accurate assurance to long brilliant switching time, can ensure that long brilliant quality and be finally made turning of cell piece Change efficiency, it is to avoid because of can not accurate assurance by the melting stage be switched to that the switching time of crystal growing stage causes accordingly due to melt Deficiency of time or melt overlong time and the problem of produced polycrystalline silicon ingot casting Quality Down that causes.
12, fusion process is divided into and hexahedro adds heat fusing, five faces add heat fusing and subsequent melting three key steps, heating side Formula is reasonable in design, and heating power is separately individually controlled, and not only control simplicity and heats more preferably, can be effectively improved melt During the rate of heat addition of crucible bottom, beneficially crucible bottom gas discharge, it is thus possible to effectively reduce the bottom of ingot casting finished product Oxygen content, can significantly improve yield rate and the quality of ingot casting finished product；Meanwhile, can be to melt during polycrystalline silicon ingot casting to long crystalline substance Switching time carries out accurate assurance, can be effectively improved crystal growth quality, reduces viscous crucible rate, improves the conversion effect of solar battery sheet Rate, can be effectively improved yield rate.
13, practical, by coating one layer of base coat with boron nitride as primary raw material in crucible bottom, and use Hexahedro heater heats, it is simple to batch production, and widely applicable.
In sum, the inventive method step is simple, reasonable in design and realization is easy, using effect is good, by crucible One layer of base coat with boron nitride as primary raw material of bottom coating, and use hexahedro heater to heat, can effectively drop Low crucible bottom oxygen content, and can effectively reduce the Hard Inclusion of ingot casting finished product, improve the quality of ingot casting finished product.
Below by drawings and Examples, technical scheme is described in further detail.
Accompanying drawing explanation
Fig. 1 is the method flow block diagram of the present invention.
Fig. 2 is the structural representation of the crucible of band base coat of the present invention.
Fig. 3 is the structural representation of baking oven of the present invention.
Fig. 4 is the method flow block diagram that the present invention coats boron nitride coating material bottom polysilicon ingot crucible.
Fig. 5 is used the use view of hexahedro heater by the present invention.
Fig. 6 is used the schematic block circuit diagram of hexahedro heater by the present invention.
Fig. 7 is temperature and the power using the present invention top heater and side heater when melting.
Description of reference numerals:
1 crucible；2 top heater；2-1 top firing power supply；
3 bottom heaters；3-1 bottom-heated power supply；4 side heater；
4-1 sidepiece heating power supply；5 DS blocks；6 heating power adjusting meanss；
7 crucible guard boards；8 main controllers；9 polycrystalline silicon ingot or purifying furnaces；
10 top firing temperature detecting units；
11 sidepiece heating-up temperature detector units；
12 bottom-heated temperature detecting units；13 heat-preservation cylinders；
14 pressure pins；15 horizontal heaters；16 vertical heaters；
17 graphite cushion blocks.
Detailed description of the invention
Embodiment 1
A kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting as shown in Figure 1, comprises the following steps:
Prepared by step one, crucible bottom coating, process is as follows:
Step 101, coating spraying liquid prepare: by organic cementing agent, deionized water and boron nitride by 1: 2～2.5: 0.8～ The mass ratio of 1.2 uniformly mixes, and obtains coating spraying liquid；
Step 102, spraying: use spraying equipment by the even application of coating spraying liquid described in step 101 to crucible 1 On bottom surface, portion, 1m in described crucible 1 inner bottom surface2In region, in the described coating spraying liquid of spraying, the quality of contained boron nitride is 100g～150g；
Described crucible 1 uses silica crucible for polycrystalline silicon ingot or purifying furnace 9；
Step 103, drying: crucible 1 described in step 102 is placed horizontally in drying plant, and uses described drying Equipment and under 90 DEG C of temperature conditionss, the described coating spraying liquid being sprayed in crucible 1 inner bottom surface being dried, it is thus achieved that the end Portion's coating 2, refers to Fig. 2；
Step 2, charging: in step one, in the crucible 1 of band base coat 2, load silicon material, and by the crucible of built-in silicon material 1 loads in polycrystalline silicon ingot or purifying furnace 9；
As shown in Figure 5 and Figure 6, polycrystalline silicon ingot or purifying furnace 9 is built with hexahedro heater；Described hexahedro heater includes cloth Be located at the bottom heater 3 below crucible 1, be laid in the top heater 2 above crucible 1 and four be laid in crucible 1 respectively The side heater 4 of four side-wall outer side, described crucible 1 be cube crucible and its be that level is laid, described top firing Device 2 and bottom heater 3 are all laid in level, four described side heater 4 all in vertically to laying；
Step 3, preheating: top heater 2, bottom heater 3 and four described side heater 4 are all opened, and adopts With polycrystalline silicon ingot or purifying furnace 9, the silicon material being loaded in crucible 1 is preheated, and the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is progressively carried Rise to T1；Preheating time is 5h, wherein T1=1200 DEG C；
Step 4, fusing, process is as follows:
Step 401, for the first time intensification: use polycrystalline silicon ingot or purifying furnace 9 that the silicon material being loaded in crucible 1 is melted, fusing Temperature is stepped up to T2 by T1；Wherein T2=1380 DEG C；
Step 402, second time heat up: the silicon material using polycrystalline silicon ingot or purifying furnace 9 to continue being loaded in crucible 1 melts, Fusion temperature is stepped up to T3 by T2；Wherein T3=1550 DEG C；
Step 403, subsequent melting: after the silicon material in crucible 1 all melts, by the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 Controlling at T3, the heating power of the most described top heater 2 and four described side heater 4 all begins to decline, and treats described After the heating power of top heater 2 and four described side heater 4 all stops decline and persistent period t, melt process is complete Become；Wherein t=30min；
Top heater 2 described in step 401, step 402 and step 403 and four described side heater 4 are in Opening, described bottom heater 3 is closed；
Step 5, long crystalline substance: carry out after the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is gradually decreased to polysilicon crystal temperature by T3 Directional solidification, until completing long brilliant process；Wherein polysilicon crystal temperature is 1430 DEG C；
Step 6, anneal and cool down: after long brilliant process completes in step 5, anneal and cool down, and obtaining and be processed into The described polycrystalline silicon ingot casting of type.
Wherein, carrying out crucible bottom coating when preparing in step one, the painting method of crucible bottom coating 2 refers to Fig. 4.
Time actually used, can according to specific needs, to cementing agent organic in coating spraying liquid described in step 101, go from The mass ratio of sub-water and boron nitride adjusts accordingly.
In the present embodiment, described organic cementing agent is phenolic aldehyde-neoprene adhesive.
Wherein, the kind of phenolic aldehyde-neoprene adhesive is more, mainly include anchor 801 seccotine, hundred glue, JX- 15-1 glue, FN-303 glue, CX-401 glue, XY-401 glue, CH-406 glue etc..Above-mentioned phenolic aldehyde-neoprene adhesive is commercially available Commodity, can directly obtain.
Time actually used, described organic cementing agent can also be organic silicon adhesive, epoxy adhesive, Instant adhesive, Acrylic acid adhesive, polyvinyl alcohol adhesive, Polyvinyl acetate adhesive, AE SGA, butvar adhesive are viscous Agent or glass cement.
Wherein, organic silicon adhesive (also referred to as organosilicon adhesive) point one pack system, bi-component, room temperature vulcanization and heating sulfur Change etc. multiple, the major product trade mark of room temperature vulcanized has 703,704, FS-203, GD-400 etc..According to solidification temperature, organic Silica gel stick can be divided into hot setting, low-temperature setting and cold curing three class.Organic silicon adhesive of the present invention is low Temperature curing organic silicon adhesive.
Epoxy adhesive is Vinylidene Chloride epoxy adhesive or furan modified epoxy adhesive.
Instant adhesive is also referred to as instant glue, and conventional is ethyl α-cyanoacrylate, product designation 502 glue；Medical Alpha-cyanoacrylate butyl ester, product designation 504 glue.
Acrylic acid adhesive, commercially available kind has SA-200, AB glue, J-39, J-50, SGA-404, SGA etc..
In the present embodiment, described boron nitride is boron nitride powder.
In the present embodiment, described boron nitride is hexagonal boron nitride.
In the present embodiment, spraying equipment described in step 102 is liquid spray gun.
Time actually used, spraying equipment described in step 102 can also be other type of liquid spraying equipment.
In the present embodiment, drying plant described in step 103 is baking oven.
As it is shown on figure 3, crucible 1 described in step 102 is cube crucible；Crucible 1 described in step 103 and described baking oven All lay in level；
Described baking oven includes casing, be laid in the horizontal heater 15 bottom crucible 1 and four be laid in crucible 1 respectively The vertical heater 16 of four side-wall outer side, four described vertical heaters 16 are respectively positioned on above horizontal heater 15, described water The graphite cushion block 17 placed for crucible 1 it is provided with on flat heater 15.
In the present embodiment, described horizontal heater 15 and four described vertical heaters 16 are resistance heater.
In the present embodiment, when step 102 sprays, 1m in described crucible 1 inner bottom surface2In region, spraying is described In coating spraying liquid, the quality of contained boron nitride is 150g.
Preferably, when step 102 sprays, 1m in described crucible 1 inner bottom surface2The described coating of spraying in region In spray coating liquor, the quality of contained boron nitride is 100g～150g.
During actually used, can according to specific needs, to 1m in crucible 1 inner bottom surface2The described painting of spraying in region In layer spray coating liquor, the quality of contained boron nitride adjusts accordingly.
In the present embodiment, when step 103 is dried, first use described drying plant that crucible 1 is heated to 90 DEG C, then Carry out being incubated till the described coating spraying liquid being sprayed in crucible 1 inner bottom surface is dried.
Actual when drying, can adjust accordingly drying temperature according to specific needs.
It is good etc. that boron nitride owing to containing in described base coat has good heat conductivity, good stability, resistance to elevated temperatures Advantage, can effectively strengthen the heat-conducting effect bottom crucible 1, can be effectively improved melting efficiency, and being difficult to of crucible 1 bottom gas Get rid of, can effectively reduce the oxygen content bottom crucible 1, make the oxygen content bottom ingot casting finished product reduce.Meanwhile, boron nitride and oxygen exist Under high temperature, reaction generates B2O3And nitrogen dioxide gas (NO2) etc., the oxygen content bottom crucible 1 can be reduced further, and raw The B become2O3Compare Si3N4Stable, it is not easily formed Hard Inclusion during ingot casting, thus can effectively reduce the Hard Inclusion of ingot casting finished product, with Time can be effectively improved the minority carrier life time of ingot casting finished product, the quality of ingot casting finished product can be effectively improved.
At present, polycrystalline silicon ingot casting method mainly has half casting process and fine melt ingot casting method two kinds, and half casting process is also referred to as There is seed crystal ingot casting polycrystalline silicon process, refer to use grade silicon material to carry out epitaxial growth as nucleating center, cast low defect Gao Pin The polycrystalline silicon ingot casting of matter；Fine melt ingot casting method is also referred to as without seed crystal ingot casting polycrystalline silicon process or without seed crystal efficient polycrystalline silicon technology, refers to Non-silicon material is used to prepare shaggy heterogeneous forming core layer in crucible bottom, during by the roughness of control forming core layer with forming core Degree of supercooling obtains bigger nucleation rate, casts low defect high-quality polycrystalline silicon ingot casting.At present, polycrystalline silicon ingot casting method is cast with fine melt Ingot method is main.
In the present embodiment, when step 2 feeds, feed according to the loading method of conventional fine melt ingot casting method.
In the present embodiment, polycrystalline silicon ingot or purifying furnace 9 described in step 2 is G5 type ingot furnace.Further, described polycrystalline silicon ingot casting Stove 9 is specially the G5 type ingot furnace that Zhejiang Jingsheng Electrical and Mechanical Co., Ltd. produces.Described crucible 1 be silica crucible and its be G5 Crucible, and the polycrystalline silicon ingot casting produced is G5 ingot.
Time actually used, the charge of described silica crucible is about 600kg.
In the present embodiment, the charge of described silica crucible is 560kg.During actually used, can be according to concrete need Want, the charge of described silica crucible is adjusted accordingly.
In conjunction with Fig. 6, in the present embodiment, described top heater 2, bottom heater 3 and four described side heater 4 are equal It is connected with heating power adjusting means 6；
In step 3 in warm, use heating power adjusting means 6 to top heater 2, bottom heater 3 and four The heating power of individual described side heater 4 synchronizes to be stepped up.
In the present embodiment, hexahedro heater described in step 2 also includes main controller 8 and temperature-detecting device, described temperature Top firing temperature detecting unit 10 that degree detection device includes detecting the heating-up temperature of top heater 2 in real time, right Sidepiece heating-up temperature detector unit 11 that the heating-up temperature of side heater 4 detects in real time and adding bottom heater 3 The bottom-heated temperature detecting unit 12 that hot temperature detects in real time, described top firing temperature detecting unit 10, sidepiece add Hot temperature detecting unit 11 and bottom-heated temperature detecting unit 12 are all connected with main controller 8；Set in described polycrystalline silicon ingot or purifying furnace 9 Being equipped with heat-preservation cylinder 13, described hexahedro heater is positioned at heat-preservation cylinder 13.Meanwhile, described main controller 8 arranges list with parameter respectively Unit 14 and display unit 15 connect.
In the present embodiment, described bottom heater 3 is fixed on the DS block 5 being supported in bottom crucible 1, described bottom-heated Distance between bottom device 3 top and DS block 5 is 0.5cm～3m.
During actual installation, can according to specific needs the distance between bottom bottom heater 3 top and DS block 5 be carried out Corresponding regulation.
Wherein, DS block 5 is graphite block, and the heat conductivity of described graphite block is the strongest.Described DS block 5 also referred to as directional solidification block or DS-BLOCK。
In the present embodiment, described heating power adjusting means 6 is connected with main controller 8.
Described top firing power supply 2-1, sidepiece heating power supply 4-1 and bottom-heated power supply 3-1 are power adjustable economize on electricity Source, and top heater 2, bottom heater 3 be respectively adopted three different power supplys (i.e. with four described side heater 4 Described top firing power supply, described sidepiece heating power supply and described bottom-heated power supply), top heater 2 can be realized, bottom adds Hot device 3 and the independent control of side heater 4, use easy and simple to handle and using effect good.
In the present embodiment, described heating power adjusting means 6 includes three heating power regulation equipment, adds described in three Thermal power regulation equipment is respectively the first heating power regulation equipment, right being adjusted the heating power of top heater 2 The second heating power that the heating power of bottom heater 3 is adjusted regulates equipment and to four described side heater 4 Heating power carries out the 3rd heating power regulation equipment of adjusted in concert.
Time actually used, three described heating power regulation equipment can also share a described heating power regulation and set Standby, only need the purpose that can reach three described power supplys are respectively controlled.
In the present embodiment, described bottom heater 3 is positioned at the underface of crucible 1.
In the present embodiment, described top heater 2, side heater 4 and bottom heater 3 are resistance heater.
Wherein, described top heater 2 and side heater 4 are the existing heating that existing polycrystalline silicon ingot or purifying furnace uses Device, described top heater 2 and the structure of four described side heater 4 and installation position are existing polycrystalline silicon ingot or purifying furnace phase With.Each described side heater 4 all sidewalls with crucible 1 on its inside are parallel laying.
In the present embodiment, the resistance wire material of described bottom heater 3 is the alloy cpds such as Ni, Cr, Mn.
In the present embodiment, four side-wall outer side of described crucible 1 are provided with crucible guard boards 7, described side heater 4 Outside crucible guard boards 7；Described crucible guard boards 7 is in vertically to the graphite cake laid.
Meanwhile, it is additionally provided with pressure pin 14 below described crucible 1.
During actual installation, described top heater 2 and four described side heater 4 are all lifted on polycrystalline by lifting part On the top cover of silicon ingot furnace 9.
In the present embodiment, in step 3 in warm neutralization procedure 401 in hexahedro heating fusion process, synchronization institute The heating power stating the described side heater 4 of top heater 2, bottom heater 3 and four is the most identical；In step 402 five Heating fusion process neutralization procedure 403 in subsequent melting during, top heater 2 described in synchronization and four described sidepieces The heating power of heater 4 is the most identical.
In step 3 in warm neutralization procedure 401 in hexahedro heating fusion process, top firing described in synchronization Device 2, bottom heater 3 are the most identical with the heating-up temperature of four described side heater 4；In step 402, five faces add heat fusing mistake In journey neutralization procedure 403 subsequent melting during, top heater 2 described in synchronization and four described side heater 4 Heating-up temperature is the most identical.
Further, heating-up temperature or the fusion temperature of described polycrystalline silicon ingot or purifying furnace 9 is top heater 2 or side heater 4 Heating-up temperature.
In the present embodiment, in step 3 in warm, by top heater 2, bottom heater 3 and four described sidepieces The heating power of heater 4 synchronizes to be stepped up, and top heater 2, bottom heater 3 and four described sidepieces is added The heating power of hot device 4 is all stepped up to P1, wherein P1=75kW.
In the present embodiment, in step 3, preheating time is 5h；In warm, by the heating power of polycrystalline silicon ingot or purifying furnace 9 Step up to P1 with the rate of rise of 10kW/h～15kW/h；
The heating power of described polycrystalline silicon ingot or purifying furnace 9 is top heater 2 or the heating power of side heater 4.
Actual when preheating, can according to specific needs, to the growth speed of heating power in preheating time, warm The value size of rate and T1 and P1 adjusts accordingly.
When step 4 melts, can according to specific needs the value size of T2, T3 and t be carried out respectively accordingly Adjust.
In the present embodiment, in step 401 in hexahedro heating fusion process, described top heater 2, bottom heater 3 and The heating power of four described side heater 4 is P1；
In step 402 in five heating fusion processes, adding of described top heater 2 and four described side heater 4 Thermal power is P1；
In step 403 subsequent melting during, after the silicon material in crucible 1 all melts, described top heater 2 and four The heating power of individual described side heater 4 synchronizes progressively to decline, to top heater 2 or the heating of side heater 4 Changed power situation is observed, and when the heating power of top heater 2 or side heater 4 drops to P2, keeps P2 not Become and after persistent period t, melt process completes；Wherein, P2=35kW.
Actual when melting, according to the difference of charge in crucible 1, the size of P2 is accordingly in the range of 25kW～45kW It is adjusted.
In the present embodiment, in step 4 in fusion process, in polycrystalline silicon ingot or purifying furnace 9, it is filled with noble gas and by polysilicon Ingot furnace 9 internal gas pressure is maintained at Q1, wherein Q1=600mbar.
Actual when melting, can according to specific needs the value size of Q1 be adjusted accordingly.
In the present embodiment, after the silicon material in crucible 1 all melts, the heating and temperature control of polycrystalline silicon ingot or purifying furnace 9 is existed T3, and the time dependent curve of heating power (i.e. power curve) of polycrystalline silicon ingot or purifying furnace 9 is observed, refer to Fig. 7.Figure In 7, fine line is the time dependent curve of heating power of polycrystalline silicon ingot or purifying furnace 9, and needing solid line is adding of polycrystalline silicon ingot or purifying furnace 9 The time dependent curve of hot temperature, vertical line is alarming line when all melting of the silicon material in crucible 1.As seen from Figure 7, treat After silicon material in crucible 1 all melts, the power curve of described polycrystalline silicon ingot or purifying furnace 9 begins to decline, and treats polycrystalline silicon ingot or purifying furnace 9 After power curve declines and walks flat 30min, melt process completes, and enters crystal growing stage afterwards；A point in i.e. Fig. 7 is melt mistake The time point that journey completes.
In actual mechanical process, just can accurately be determined the time point that melt process completes by observed power curve, i.e. by Melting stage is switched to some switching time of crystal growing stage.Practical operation is easy, and realizes conveniently, and energy accurate assurance is by melting rank Section is switched to the switching time of crystal growing stage.
In the present embodiment, when melting in step 4, process is as follows:
1st step, insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace 9 at T1, and be incubated 0.5h；
2nd step to the 5th step, heat up and pressurize: by first to rear point of four step by the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 by T1 by Gradually being promoted to T4, the heating-up time is 0.5h (total time of the i.e. the 2nd step to the 5th step is 0.5h)；Temperature-rise period is cast to polysilicon It is filled with noble gas in ingot stove 9 and polycrystalline silicon ingot or purifying furnace 9 internal gas pressure is stepped up to Q1；Wherein, T4=1250 DEG C；
6th step, for the first time intensification and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is gradually promoted to by T4 T5 and liter The temperature time is 4h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace 9 internal gas pressure is maintained at Q1；Wherein, T5=1450 DEG C；
7th step: second time heats up and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is gradually promoted to T6 and liter by T5 The temperature time is 4h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace 9 internal gas pressure is maintained at Q1；Wherein, T6=1500 DEG C；
8th step, third time heat up and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is gradually promoted to T3 and liter by T6 The temperature time is 4h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace 9 internal gas pressure is maintained at Q1；
9th step, insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace 9 at T3, and be incubated 4h；In insulating process, described Polycrystalline silicon ingot or purifying furnace 9 internal gas pressure is maintained at Q1；
10th step, persistently insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace 9 at T3, and be incubated 6h, until crucible 1 Interior silicon material all melts；In insulating process, described polycrystalline silicon ingot or purifying furnace 9 internal gas pressure is maintained at Q1.
In the present embodiment, by rear point of four steps by the heating-up temperature of described ingot furnace by T1 the most gradually in the 2nd step to the 5th step When being promoted to T4, each step promotes temperature 5 DEG C～8 DEG C, and each step promotes and is both needed to 5min～10min.
In the present embodiment, the 6th step is carried out heat up for the first time and carry out in pressure maintaining period, in the 7th step second time heat up and Carry out third time in pressure maintaining period, in the 8th step heat up and pressure maintaining period neutralization the 9th step carries out in insulating process, be both needed to many The heating power situation of change of crystal silicon ingot furnace 9 is observed, and guarantees the heating power change of polycrystalline silicon ingot or purifying furnace 9 steadily.
The heating power of described polycrystalline silicon ingot or purifying furnace 9 is top heater 2 or the heating power of side heater 4.
During it is to say, the 6th step to the 9th step melts, it is necessary to make power curve steadily advance, it is impossible to occur more Significantly sags and crests, so can bring increasing of Hard Inclusion.
In the present embodiment, when heating up and pressurize in the 2nd step to the 5th step, process is as follows:
2nd step, the first step promote: by 1200 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1220 DEG C, and heat up Time is 7min.
3rd step, second step promote: by 1220 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1235 DEG C, and heat up Time is 8min.
4th step, the 3rd step promote: by 1235 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1242 DEG C, and heat up Time is 5min.
5th step, the 4th step promote: by 1242 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1250 DEG C, and heat up Time is 5min.
In the present embodiment, the 10th step is treated the silicon material in crucible 1 all melt and described ingot furnace send " fusing complete report Alert " after, need manual intervention, the decline situation of power curve is observed, treat that the power curve of described ingot furnace declines and walks After flat 30min, melt process completes, and manual intervention afterwards will be cut into crystal growing stage the melting stage.
In the present embodiment, described noble gas is argon.
In the present embodiment, after using polycrystalline silicon ingot or purifying furnace and utilizing the crucible 1 of band base coat 2 to carry out polycrystalline silicon ingot casting, The surface free from admixture of machine-shaping ingot casting finished product, without viscous crucible phenomenon, bottom ingot casting, oxygen content reduces by more than 70%, minority carrier life time ＞ 5.5us (microsecond), Hard Inclusion ratio ＜ 0.5%, yield rate is 78%.
Embodiment 2
In the present embodiment, as different from Example 1: organic cementing agent, deionized water and boron nitride are pressed by step 101 The mass ratio of 1: 2: 0.8 uniformly mixes, and obtains coating spraying liquid；Described organic cementing agent is organic silicon adhesive；In step 102 When spraying, 1m in described crucible 1 inner bottom surface2The quality of contained boron nitride in the described coating spraying liquid of spraying in region For 100g；When step 103 is dried, use described drying plant and to being sprayed in crucible 1 under 80 DEG C of temperature conditionss Described coating spraying liquid on bottom surface, portion is dried, and first uses described drying plant that crucible 1 is heated to 80 DEG C, then enters Row insulation is till the described coating spraying liquid being sprayed in crucible 1 inner bottom surface is dried；In step 3, preheating time is 4h And T1=1285 DEG C, P1=100kW；In step 401 T2=1400 DEG C, in step 402 T3=1560 DEG C, t=in step 403 20min, P2=45kW；Q1=650mbar in step 4；In 1st step, temperature retention time is 0.4h；T4=in 2nd step to the 5th step 1325 DEG C, the heating-up time is 0.4h；In 6th step, T5=1460 DEG C and heating-up time are 3.5h；T6=1510 DEG C and liter in 7th step The temperature time is 3.5h；In 8th step, T3=1560 DEG C and heating-up time are 3.5h；In 9th step, temperature retention time is 3.5h；In 10th step Temperature retention time is 4h.
In the present embodiment, when heating up and pressurize in the 2nd step to the 5th step, process is as follows:
2nd step, the first step promote: by 1285 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1290 DEG C, and heat up Time is 5min.
3rd step, second step promote: by 1290 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1295 DEG C, and heat up Time is 5min.
4th step, the 3rd step promote: by 1295 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1315 DEG C, and heat up Time is 9min.
5th step, the 4th step promote: by 1315 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1325 DEG C, and heat up Time is 5min.
In the present embodiment, remaining method step and technological parameter are the most same as in Example 1.
In the present embodiment, after using polycrystalline silicon ingot or purifying furnace and utilizing the crucible 1 of band base coat 2 to carry out polycrystalline silicon ingot casting, The surface free from admixture of machine-shaping ingot casting finished product, without viscous crucible phenomenon, bottom ingot casting, oxygen content reduces by more than 68%, minority carrier life time ＞ 5.5us (microsecond), Hard Inclusion ratio ＜ 0.5%, yield rate is 80%.
Embodiment 3
In the present embodiment, as different from Example 1: organic cementing agent, deionized water and boron nitride are pressed by step 101 The mass ratio of 1: 2.5: 0.8 uniformly mixes, and obtains coating spraying liquid；Described organic cementing agent is epoxy adhesive；In step 102 When spraying, 1m in described crucible 1 inner bottom surface2The quality of contained boron nitride in the described coating spraying liquid of spraying in region For 130g；When step 103 is dried, use described drying plant and to being sprayed in crucible 1 under 100 DEG C of temperature conditionss Described coating spraying liquid on bottom surface, portion is dried, and first uses described drying plant that crucible 1 is heated to 100 DEG C, then Carry out being incubated till the described coating spraying liquid being sprayed in crucible 1 inner bottom surface is dried；In step 3, preheating time is 6h and T1=1125 DEG C, P1=50kW；In step 401 T2=1350 DEG C, in step 402 T3=1540 DEG C, t=in step 403 40min, P2=25kW；Q1=550mbar in step 4；In 1st step, temperature retention time is 0.6h；T4=in 2nd step to the 5th step 1190 DEG C, the heating-up time is 0.6h；In 6th step, T5=1440 DEG C and heating-up time are 4.5h；T6=1490 DEG C and liter in 7th step The temperature time is 4.5h；In 8th step, T3=1540 DEG C and heating-up time are 4.5h；In 9th step, temperature retention time is 4.5h；In 10th step Temperature retention time is 8h.
In the present embodiment, when heating up and pressurize in the 2nd step to the 5th step, process is as follows:
2nd step, the first step promote: by 1125 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1140 DEG C, and heat up Time is 9min.
3rd step, second step promote: by 1140 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1155 DEG C, and heat up Time is 8min.
4th step, the 3rd step promote: by 1155 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1175 DEG C, and heat up Time is 10min.
5th step, the 4th step promote: by 1175 DEG C, the heating-up temperature of polycrystalline silicon ingot or purifying furnace 9 is promoted to 1190 DEG C, and heat up Time is 9min.
In the present embodiment, remaining method step and technological parameter are the most same as in Example 1.
In the present embodiment, after using polycrystalline silicon ingot or purifying furnace and utilizing the crucible 1 of band base coat 2 to carry out polycrystalline silicon ingot casting, The surface free from admixture of machine-shaping ingot casting finished product, without viscous crucible phenomenon, bottom ingot casting, oxygen content reduces by more than 75%, minority carrier life time ＞ 5.5us (microsecond), Hard Inclusion ratio ＜ 0.5%, yield rate is 82%.
Embodiment 4
In the present embodiment, as different from Example 1: organic cementing agent, deionized water and boron nitride are pressed by step 101 The mass ratio of 1: 2.5: 1.2 uniformly mixes, and obtains coating spraying liquid；Described organic cementing agent is Instant adhesive；In step 102 When spraying, 1m in described crucible 1 inner bottom surface2The quality of contained boron nitride in the described coating spraying liquid of spraying in region For 180g.
In the present embodiment, remaining method step and technological parameter are the most same as in Example 1.
In the present embodiment, compared with conventional crucible, use polycrystalline silicon ingot or purifying furnace and utilize the crucible 1 of band base coat 2 to enter After row polycrystalline silicon ingot casting, the surface free from admixture of machine-shaping ingot casting finished product, without viscous crucible phenomenon, bottom ingot casting, oxygen content reduces by 72% Above, minority carrier life time ＞ 5.5us (microsecond), Hard Inclusion ratio ＜ 0.5%, yield rate is 75%.
Embodiment 5
In the present embodiment, as different from Example 1: organic cementing agent, deionized water and boron nitride are pressed by step 101 The mass ratio of 1: 2: 1.2 uniformly mixes, and obtains coating spraying liquid；Described organic cementing agent is acrylic acid adhesive；In step 102 When spraying, 1m in described crucible 1 inner bottom surface2The quality of contained boron nitride in the described coating spraying liquid of spraying in region For 200g.
In the present embodiment, remaining method step and technological parameter are the most same as in Example 1.
In the present embodiment, compared with conventional crucible, use polycrystalline silicon ingot or purifying furnace and utilize the crucible 1 of band base coat 2 to enter After row polycrystalline silicon ingot casting, the surface free from admixture of machine-shaping ingot casting finished product, without viscous crucible phenomenon, bottom ingot casting, oxygen content reduces by 70% Above, minority carrier life time ＞ 5.5us (microsecond), Hard Inclusion ratio ＜ 0.5%, yield rate is 72%.
The above, be only presently preferred embodiments of the present invention, not impose any restrictions the present invention, every according to the present invention Any simple modification, change and the equivalent structure change that above example is made by technical spirit, all still falls within skill of the present invention In the protection domain of art scheme.

Claims (10)

1. the polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting, it is characterised in that the method includes following Step:
Prepared by step one, crucible bottom coating, process is as follows:
Step 101, coating spraying liquid are prepared: by organic cementing agent, deionized water and boron nitride by 1: (2～2.5): (0.8～ 1.2) mass ratio uniformly mixes, and obtains coating spraying liquid；
Step 102, spraying: use spraying equipment by the inside of the even application of coating spraying liquid described in step 101 to crucible (1) On bottom surface, 1m in described crucible (1) inner bottom surface2In region, in the described coating spraying liquid of spraying, the quality of contained boron nitride is 100g～200g；
Described crucible (1) is that polycrystalline silicon ingot or purifying furnace (9) uses silica crucible；
Step 103, drying: crucible described in step 102 (1) is placed horizontally in drying plant, and uses described drying to set It is standby and under 80 DEG C～100 DEG C of temperature conditionss, the described coating spraying liquid being sprayed in crucible (1) inner bottom surface is dried, Obtain base coat (2)；
Step 2, charging: in step one, in the crucible (1) of band base coat (2), load silicon material, and by the crucible of built-in silicon material (1) load in polycrystalline silicon ingot or purifying furnace (9)；
Polycrystalline silicon ingot or purifying furnace (9) is built with hexahedro heater；Described hexahedro heater includes being laid in crucible (1) lower section Bottom heater (3), the top heater (2) being laid in crucible (1) top and four four sides being laid in crucible (1) respectively Side heater (4) outside wall, described crucible (1) be cube crucible and its be level lay, described top heater (2) All lay in level with bottom heater (3), four described side heater (4) all in vertically to laying；
Step 3, preheating: top heater (2), bottom heater (3) and four described side heater (4) are all opened, and Use polycrystalline silicon ingot or purifying furnace (9) that the silicon material being loaded in crucible (1) is preheated, and by the heating temperature of polycrystalline silicon ingot or purifying furnace (9) Degree steps up to T1；Preheating time is 4h～6h, wherein T1=1125 DEG C～1285 DEG C；
Step 4, fusing, process is as follows:
Step 401, for the first time intensification: use polycrystalline silicon ingot or purifying furnace (9) that the silicon material being loaded in crucible (1) is melted, fusing Temperature is stepped up to T2 by T1；Wherein T2=1350 DEG C～1400 DEG C；
Step 402, second time heat up: use polycrystalline silicon ingot or purifying furnace (9) to continue to melt the silicon material being loaded in crucible (1), Fusion temperature is stepped up to T3 by T2；Wherein T3=1540 DEG C～1560 DEG C；
Step 403, subsequent melting: after the silicon material in crucible (1) all melts, by the heating-up temperature of polycrystalline silicon ingot or purifying furnace (9) Controlling at T3, the heating power of the most described top heater (2) and four described side heater (4) all begins to decline, and treats The heating power of described top heater (2) and four described side heater (4) all stops declining and after persistent period t, molten Material process completes；Wherein t=20min～40min；
Top heater described in step 401, step 402 and step 403 (2) and four described side heater (4) are in Opening, described bottom heater (3) is closed；
Step 5, long crystalline substance: it is fixed to carry out after the heating-up temperature of polycrystalline silicon ingot or purifying furnace (9) is gradually decreased to polysilicon crystal temperature by T3 To solidification, until completing long brilliant process；Wherein polysilicon crystal temperature is 1420 DEG C～1440 DEG C；
Step 6, anneal and cool down: after long brilliant process completes in step 5, anneal and cool down, and obtaining machine-shaping Described polycrystalline silicon ingot casting.
2. according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 1, its feature It is: organic binder bond described in step 101 is phenolic aldehyde-neoprene adhesive, epoxy adhesive, Instant adhesive, propylene Acid adhesive, polyvinyl alcohol adhesive, Polyvinyl acetate adhesive, AE SGA, butvar adhesive stick or Glass cement；
Described boron nitride is hexagonal boron nitride.
3., according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 1 or 2, it is special Levy and be: in step 3 in warm neutralization procedure 401 in hexahedro heating fusion process, top heater described in synchronization (2), bottom heater (3) is the most identical with the heating power of four described side heater (4)；In step 402, five faces add hot melt In change process neutralization procedure 403 subsequent melting during, top heater described in synchronization (2) and the heating of four described sidepieces The heating power of device (4) is the most identical.
4., according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 1 or 2, it is special Levy and be: in step 3 in warm, by top heater (2), bottom heater (3) and four described side heater (4) heating power synchronizes to be stepped up, and top heater (2), bottom heater (3) and four described sidepieces is added The heating power of hot device (4) is all stepped up to P1, wherein P1=50kW～100kW；
In step 401 in hexahedro heating fusion process, described top heater (2), bottom heater (3) and four described sidepieces The heating power of heater (4) is P1；
In step 402 in five heating fusion processes, adding of described top heater (2) and four described side heater (4) Thermal power is P1；
In step 403 subsequent melting during, after the silicon material in crucible (1) all melts, described top heater (2) and four The heating power of individual described side heater (4) synchronizes progressively to decline, to top heater (2) or side heater (4) Heating power situation of change be observed, treat that the heating power of top heater (2) or side heater (4) drops to P2 Time, keep P2 constant and after persistent period t, melt process completes；Wherein, P2=25kW～45kW.
5., according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 1 or 2, it is special Levy and be: top heater described in step 2 (2), bottom heater (3) and four described side heater (4) all with heating PCU Power Conditioning Unit (6) connects；
In step 3 in warm, use heating power adjusting means (6) to top heater (2), bottom heater (3) and The heating power of four described side heater (4) synchronizes to be stepped up.
6. according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 5, its feature It is: described top heater (2) is connected with top firing power supply (2-1) by the first electrode, four described side heater (4) being all connected with sidepiece heating power supply (4-1) by the second electrode, described bottom heater (3) passes through the 3rd electrode and bottom Heating power supply (3-1) connects；Described top firing power supply (2-1), sidepiece heating power supply (4-1) and bottom-heated power supply (3-1) All being connected with heating power adjusting means (6), described heating power adjusting means (6) is to top firing power supply (2-1), sidepiece The PCU Power Conditioning Unit that the output of heating power supply (4-1) and bottom-heated power supply (3-1) is adjusted respectively.
7., according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 1 or 2, it is special Levying and be: when melting in step 4, process is as follows:
1st step, insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace (9) at T1, and be incubated 0.4h～0.6h；
2nd step to the 5th step, heat up and pressurize: by first to rear point of four steps by the heating-up temperature of polycrystalline silicon ingot or purifying furnace (9) by T1 the most gradually Being promoted to T4, the heating-up time is 0.4h～0.6h；Temperature-rise period is filled with noble gas in polycrystalline silicon ingot or purifying furnace (9) and will be many Crystal silicon ingot furnace (9) internal gas pressure steps up to Q1；Wherein, T4=1190 DEG C～1325 DEG C, Q1=550mbar～650mbar；
6th step, for the first time intensification and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace (9) is gradually promoted to by T4 T5 and intensification Time is 3.5h～4.5h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace (9) internal gas pressure is maintained at Q1；Wherein, T5=1440 DEG C～ 1460℃；
7th step: second time heats up and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace (9) is gradually promoted to T6 and intensification by T5 Time is 3.5h～4.5h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace (9) internal gas pressure is maintained at Q1；Wherein, T6=1490 DEG C～ 1510℃；
8th step, third time heat up and pressurize: the heating-up temperature of polycrystalline silicon ingot or purifying furnace (9) is gradually promoted to T3 and intensification by T6 Time is 3.5h～4.5h, and in temperature-rise period, polycrystalline silicon ingot or purifying furnace (9) internal gas pressure is maintained at Q1；
9th step, insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace (9) at T3, and be incubated 3.5h～4.5h；Insulating process In, described polycrystalline silicon ingot or purifying furnace (9) internal gas pressure is maintained at Q1；
10th step, persistently insulation: by the heating and temperature control of polycrystalline silicon ingot or purifying furnace (9) at T3, and be incubated 4h～8h, until crucible (1) the silicon material in all melts；In insulating process, described polycrystalline silicon ingot or purifying furnace (9) internal gas pressure is maintained at Q1.
8., according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 1 or 2, it is special Levying and be: spraying equipment described in step 102 is liquid spray gun, drying plant described in step 103 is baking oven.
9. according to a kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting described in claim 8, its feature It is: described baking oven includes that casing, the horizontal heater (15) being laid in crucible (1) bottom and four are laid in crucible respectively (1) the vertical heater (16) of four side-wall outer side, four described vertical heaters (16) are respectively positioned on horizontal heater (15) Top, described horizontal heater (15) is provided with the graphite cushion block (17) placed for crucible (1).
10. reduce the method for oxygen content bottom polycrystalline silicon ingot casting according to a kind of described in claim 1 or 2, it is characterised in that: step When spraying in rapid 102,1m in described crucible (1) inner bottom surface2In region, in the described coating spraying liquid of spraying, institute is nitrogenous The quality changing boron is 100g～150g；
When step 103 is dried, first use described drying plant that crucible (1) is heated to 80 DEG C～100 DEG C, then protect Temperature is till the described coating spraying liquid being sprayed in crucible (1) inner bottom surface is dried.
CN201610695211.0A 2016-08-19 2016-08-19 A kind of polycrystalline silicon ingot casting method reducing oxygen content bottom polycrystalline silicon ingot casting Pending CN106222740A (en)

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