CN110049946A - The manufacturing method of alpha-silicon nitride powders, polycrystalline silicon ingot casting release agent and polycrystalline silicon ingot casting - Google Patents
The manufacturing method of alpha-silicon nitride powders, polycrystalline silicon ingot casting release agent and polycrystalline silicon ingot casting Download PDFInfo
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- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B21/00—Nitrogen; Compounds thereof
- C01B21/06—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron
- C01B21/068—Binary compounds of nitrogen with metals, with silicon, or with boron, or with carbon, i.e. nitrides; Compounds of nitrogen with more than one metal, silicon or boron with silicon
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- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/02—Silicon
Abstract
The purpose of the present invention is to provide a kind of alpha-silicon nitride powders, its release agent that can be suitably used as polycrystalline silicon ingot casting, even if the release property of polycrystalline silicon ingot casting is also good when the melting temperature of silicon of the release agent when increasing unidirectional solidification or when increasing the melting time of silicon.There is provided a kind of alpha-silicon nitride powders, which is characterized in that specific surface area 2m2/ g or more and 13m2/ g is hereinafter, the ratio of β type silicon nitride is 50 mass % or more, the crystallite diameter D of β type silicon nitrideCFor 150nm or more, specific surface area equivalent diameter DBETWith DCThe ratio between DBET/DCIt (nm/nm) is 3 hereinafter, the tool of curve of frequency distribution obtained from being measured as size distribution is there are two peak, the summit at the peak is in 0.5~2 μm of range and 6~30 μm of range, and the frequency ratio of aforementioned summit is 0.1~1.
Description
Technical field
The present invention relates to the silicon nitrides that can be formed in the mould with the adaptation of mold and the good release layer of release property
Powder, more particularly, to the alpha-silicon nitride powders for being suitable for release agent as polycrystalline silicon ingot casting.
Background technique
Polycrystalline silicon substrate used in solar battery is usually by using vertical Bu Liziman furnace to make molten silicon unidirectional solidification
And the polycrystalline silicon ingot casting manufactured obtains.Polycrystalline silicon substrate requires high performance and cost effective, in order to cope with the requirement, inhibits
Impurity being mixed into polycrystalline silicon ingot casting and to improve the yield rate of polycrystalline silicon ingot casting be critically important when the unidirectional solidification of molten silicon.
In the unidirectional solidification using the molten silicon of vertical Bridgman method, using the mold of quartz system etc., in order to improve polysilicon casting
The yield rate of ingot, mold require the release property of polycrystalline silicon ingot casting good, are coated with usually using inner wall (face contacted with molten silicon)
There is the mold of the release agent comprising alpha-silicon nitride powders.
Vertical Bu Liziman furnace its structurally, heat escape downwards from mold bottom surface, therefore, mold in above-below direction can
Big temperature gradient is generated, the temperature on mold top relatively heightens.In recent years, towards the polycrystalline silicon ingot casting of solar cell substrate
Increasingly tend to enlargement, temperature is increased when the silicon (fusing point: 1414 DEG C) of cast base sufficiently melts, sometimes because of cloth
The construction of Li Ziman furnace and so that the temperature on mold top is become 1500 DEG C or more such high temperature.In this case, it produces sometimes
Raw following problem: on the high mold top of temperature, the release property of polycrystalline silicon ingot casting is deteriorated or release layer is attached from mold peeling
In polycrystalline silicon ingot casting etc..Therefore, the release layer requirement of polycrystalline silicon ingot casting: though in high temperature, such as 1500 DEG C or more progress singly
To solidification, the adaptation of the release property of polycrystalline silicon ingot casting, release layer and mold is also good.
Based on such background, it is expected that developing a kind of alpha-silicon nitride powders, it is capable of forming following release layer, the demoulding
When even if layer improves unidirectional solidification to improve the yield rate of the polycrystalline silicon ingot casting for the substrate that can apply to solar battery
It is the release property of polycrystalline silicon ingot casting, also good with the adaptation of mold when the melting temperature of silicon.In addition, in order to obtain the more of strip
Crystal silicon ingot casting and when using the big mold of size in the up-down direction, especially mold top can be exposed to for a long time under high temperature,
Therefore, it is desirable to a kind of alpha-silicon nitride powders be developed, when which is capable of forming the melting of silicon when unidirectional solidification
Between it is long, the release property of polycrystalline silicon ingot casting, with the adaptation of mold also good release layer.
Such as described in patent document 1:, can when following alpha-silicon nitride powders are used as the release agent of polycrystalline silicon ingot casting
The peeling for improving workability when coating, inhibiting release agent, it is described thereby, it is possible to reduce impurity being mixed into polycrystalline silicon ingot casting
Alpha-silicon nitride powders be 90% partial size obtained using laser diffraction scattering method be 3.0~10 μm, the ratio of α phase is 20~60%,
The content of iron is 100ppm alpha-silicon nitride powders below, and size distribution has 2 maximum, one at 0.2 μm or more and small
In 1.0 μm (maximum 1), another is at 1.0 μm or more and 8.0 μm or less (maximum 2), also, each frequency of maximum 1 and 2
The ratio { (frequency of maximum 2)/(frequency of maximum 1) } of rate is 1.0~5.0, it is divided into 0.8 between maximum 1 and 2~
7.8μm。
In addition, describing in patent document 2: there is the release layer of following silicon nitride series intensity (can be avoided peeling, become
Flakiness and fall), mechanical excellent wear resistance, the release layer of the silicon nitride series is to use in the solidification of polycrystalline silicon ingot casting
Crucible in the release layer that is formed, and include 1 μm of particle below and 2 μm~50 μm of range, preferably 2 μm~5 μm of range
Particle.
Existing technical literature
Patent document
Patent document 1: Japanese Unexamined Patent Publication 2014-9111 bulletin
Patent document 2: Japanese Unexamined Patent Application Publication 2009-510387 bulletin
Summary of the invention
Problems to be solved by the invention
Although the ratio for describing α phase in patent document 1 is in specific range, obtained by size distribution measurement
Curve of frequency distribution tool be in the alpha-silicon nitride powders of specific range there are two the summit at peak, its peak and be able to suppress release agent
It peels off, reduce mixed effect of the impurity to polycrystalline silicon ingot casting, but show also, when the summit of partial size the greater is greater than 8.0 μm,
Without said effect.In addition, not recording the crystallite diameter of silicon nitride, itself and the ratio of BET diameter etc., also increased without recording
The adaptation of the release property of the melting temperature of silicon or polycrystalline silicon ingot casting when increasing the melting time of silicon, release layer and mold.
Although in addition, being described in patent document 2 in 2 μm~50 μm of big comprising 1 μm of particle and Bi Qi below
As the release layer being not easily stripped when grain, but the range of bulky grain only describes the wider range bigger than little particle, does not have
Body shows the effect when particle of two kinds of sizes is applied in combination, and as the preferred scope of bulky grain, also only describes 2
μm~5 μm.In addition, not recording the crystallite diameter of silicon nitride, itself and the ratio of BET diameter etc., the molten of silicon also is increased without recording
The adaptation of the release property of polycrystalline silicon ingot casting, release layer and mold when melting temperature or increasing the melting time of silicon.
Therefore, the object of the present invention is to provide a kind of alpha-silicon nitride powders, can suitably be used as polycrystalline silicon ingot casting
Release agent, even if when the melting temperature of silicon of the release agent when increasing unidirectional solidification or when increasing the melting time of silicon,
The release property of polycrystalline silicon ingot casting is also good.
The solution to the problem
The inventors of the present invention have made intensive studies to solve foregoing problems, discovery: using following alpha-silicon nitride powders
When release layer to form polycrystalline silicon ingot casting casting mold, even if the melting temperature of silicon when increasing unidirectional solidification, polysilicon
The release property and release layer of ingot casting are also good to the adaptation of mold, so as to complete the present invention, the alpha-silicon nitride powders tool
Have specific specific surface area, the ratio of specific β type silicon nitride, specific crystallite diameter and its with specific surface area equivalent diameter
Than there is specific size distribution, for especially curve of frequency distribution tool there are two peak, the summit at the peak of the greater is in big model
It encloses.That is, the present invention relates to items below.
(1) a kind of alpha-silicon nitride powders, which is characterized in that the specific surface area using BET method measurement is 2m2/ g or more and 13m2/
G hereinafter, β type silicon nitride ratio be 50 mass % or more, Williamson-Hall formula will be used by the powder X-ray of β type silicon nitride
The crystallite diameter for the β type silicon nitride that ray diffraction pattern calculates is set as DCWhen, DCFor 150nm or more, will be by aforementioned specific surface area
The specific surface area equivalent diameter of calculating is set as DBETWhen, DBET/DC(nm/nm) for 3 hereinafter, by based on laser diffraction scattering method
There are two peak, model of the summit at the peak at 0.5~2 μm for curve of frequency distribution tool obtained from the size distribution measurement of volume reference
Enclose the range with 6~30 μm, frequency ratio (frequency/partial size 6~30 of the summit for the range that 0.5~2 μm of partial size of aforementioned summit
μm range summit frequency) be 0.1~1.
(2) alpha-silicon nitride powders according to above-mentioned (1), which is characterized in that using Williamson-Hall formula by β type
The crystal strain for the β type silicon nitride that the powder X-ray diffraction pattern of silicon nitride calculates is 1.5 × 10-4Below.
(3) alpha-silicon nitride powders according to above-mentioned (1) or (2), which is characterized in that aforementioned summit is in 0.5~2 μm
Range and 9~30 μm of range.
(4) alpha-silicon nitride powders according to any one of above-mentioned (1)~(3), which is characterized in that the ratio of β type silicon nitride
Example is 70 mass % or more.
(5) alpha-silicon nitride powders according to any one of above-mentioned (1)~(4), which is characterized in that aforementioned specific surface area is
2m2/ g or more and 10m2/ g or less.
(6) alpha-silicon nitride powders according to any one of above-mentioned (1)~(5), which is characterized in that the content ratio of Fe is
100ppm is hereinafter, the content ratio of Al is 100ppm hereinafter, the content ratio of the metal impurities in addition to Fe and Al adds up to
100ppm or less.
(7) a kind of polycrystalline silicon ingot casting release agent, it includes the alpha-silicon nitride powders described in any one of above-mentioned (1)~(6).
(8) a kind of manufacturing method of silicon ingot casting, which is characterized in that its be make the molten silicon being contained in mold solidify it is more
The manufacturing method of crystal silicon ingot casting is coated with above-mentioned (1)~(6) using in the contact surface with aforementioned melt silicon as aforementioned mold
Any one of described in alpha-silicon nitride powders mold.
The effect of invention
Using alpha-silicon nitride powders of the invention, it is capable of providing the silicon nitride powder for being suitable for use as the release agent of polycrystalline silicon ingot casting
End, the melting temperature of silicon of the release agent when increasing unidirectional solidification or increase the melting time of silicon, can be improved
The release property and release layer of polycrystalline silicon ingot casting and the adaptation of mold.
Detailed description of the invention
Fig. 1 is used in the manufacture of the alpha-silicon nitride powders of embodiment 1~11 and comparative example 1~3 and comparative example 6~13
The schematic diagram of combustion synthesis reaction device.
Specific embodiment
The embodiment of alpha-silicon nitride powders of the invention is described in detail.
(alpha-silicon nitride powders)
Alpha-silicon nitride powders of the invention are characterized in that the specific surface area using BET method measurement is 2m2/ g or more and 13m2/
G hereinafter, β type silicon nitride ratio be 50 mass % or more, Williamson-Hall formula will be used by the powder X-ray of β type silicon nitride
The crystallite diameter for the β type silicon nitride that ray diffraction pattern calculates is set as DCWhen, DCIt, will be by aforementioned specific surface integrating for 150nm or more
Specific surface area equivalent diameter out is set as DBETWhen, DBET/DC(nm/nm) for 3 hereinafter, passing through the body based on laser diffraction scattering method
For curve of frequency distribution tool obtained from the size distribution measurement of product benchmark there are two peak, the summit at the peak is in 0.5~2 μm of model
The range with 6~30 μm is enclosed, (the frequency of the summit of 6~30 μm of frequency/partial size of range of the summit for the range that 0.5~2 μm of partial size
Rate) it is 0.1~1.The frequency ratio of aforementioned summit can for less than 1.0,0.95 or less, 0.9 or less, 0.8 or less, 0.7 or less,
0.6 or less.
The specific surface area using BET method measurement of alpha-silicon nitride powders of the invention is 2m2/ g or more and 13m2/ g or less.Than
When surface area is the range, it is capable of forming to the good release layer of the adaptation of mold.Consider from the viewpoint, further preferably compares
Surface area is 2m2/ g or more and 10m2/ g or less.The specific surface area using BET method measurement of alpha-silicon nitride powders may be 8m2/g
Below, 6m2/ g or less, 4m2/ g or less.
The ratio of the β type silicon nitride of alpha-silicon nitride powders of the invention is 50 mass % or more.The ratio of β type silicon nitride is should
When range, it is capable of forming the release property of polycrystalline silicon ingot casting, to the good release layer of the adaptation of mold.Consider from the viewpoint,
The ratio of further preferred β type silicon nitride is greater than 70 mass %.The ratio of β type silicon nitride may be 60 mass % or more, 80
Quality % or more, 90 mass % or more, 95 mass % or more, or 100 mass %.
Ingredient other than silicon nitride is preferably smaller than 3 mass % and then less than 1 mass %, particularly less than 0.1 mass %.
There are when ingredient other than silicon nitride, there is following worry: even if it is such when increasing unidirectional solidification to be unable to get the present invention
Silicon melting temperature when or when increasing the melting time of silicon also good polycrystalline silicon ingot casting release property.
The β type silicon nitride that Williamson-Hall formula will be used to be calculated by the powder X-ray diffraction pattern of β type silicon nitride
Crystallite diameter be set as DCWhen, the D of alpha-silicon nitride powders of the inventionCFor 150nm or more.DCWhen for the range, even if increasing silicon
Melting temperature increases the melting time, is also capable of forming the release property of polycrystalline silicon ingot casting, to the good demoulding of the adaptation of mold
Layer.It could be speculated that by making DCFor 150nm or more, even if being contacted for a long time at a high temperature of such as 1500 DEG C or more with molten silicon,
Alpha-silicon nitride powders of the invention can also maintain the structural stability of crystal.Consider from the viewpoint, DCPreferably 300nm or more, into
One step is preferably 500nm or more.DCIt may be 180nm or more, 200nm or more, 250nm or more, 400nm or more.
Alpha-silicon nitride powders of the invention are preferably, and the specific surface area equivalent diameter calculated by aforementioned specific surface area is set as
DBETWhen, DBET/DCIt (nm/nm) is 3 or less.DBET/DC(nm/nm) be the range when, even if increase silicon melting temperature, also can
Form the release property of polycrystalline silicon ingot casting, to the good release layer of the adaptation of mold.Its reason is still uncertain, but can speculate
Are as follows: constitute the interfacial area hour of the crystallite in a crystal grain of the silicon nitride of alpha-silicon nitride powders, it may be possible to further increase
The structural stability of the crystal of silicon nitride when being contacted for a long time with molten silicon at high temperature.DBET/DC(nm/nm) or 2 with
Under, 1.8 or less, 1.5 or less.
Alpha-silicon nitride powders of the invention and the size distribution of the volume reference based on laser diffraction scattering method measures
There are two peaks for obtained curve of frequency distribution tool, and the summit at the peak is in 0.5~2 μm of range and 6~30 μm of range, aforementioned
The frequency ratio (frequency of the summit of 6~30 μm of frequency/partial size of range of the summit for the range that 0.5~2 μm of partial size) of summit
It is 0.1~1.There are two peak, two aforementioned summits to be respectively at aforementioned range and its frequency ratio for aforementioned frequencies distribution curve tool
When for aforementioned range, release layer becomes fine and close, and release property, the release layer of polycrystalline silicon ingot casting also improve the adaptation of mold.
In two summits, summit the particle of 0.5~2 μm of range have improve the mutual adaptation of silicon nitride particle,
The effect of the adaptation of silicon nitride particle and mold is improved, and forms the effect of fine and close release layer.Therefore, summit 0.5
When~2 μm of range, it is capable of forming the good release layer of release property.And the particle for the range that summit is 6~30 μm has raising
The effect of the heat resistance of release layer.Therefore, when the range that summit is 6~30 μm, even if making silicon at a high temperature of 1500 DEG C or more
Melting, will not occur the peeling of release layer, be capable of forming good release layer.The summit of partial size smaller may be 1.5 μ
M or less, 1.0 μm or less, 0.9 μm or less.The summit of partial size the greater may be 9 μm or more, 10 μm or more, 11 μm or more,
13 μm or more, 15 μm or more, or be 25 μm or less, 20 μm or less.Here, the range of the summit of partial size smaller and partial size compared with
Any combination that may range from various ranges above-mentioned respectively of the summit of big person.In addition, frequency ratio (the grain of aforementioned summit
The frequency of the summit of 6~30 μm of frequency/partial size of range of the summit for the range that 0.5~2 μm of diameter) be 0.1~1 when, can be most
The effect for obtaining to limits respective particle is capable of forming the mutual adaptation of silicon nitride particle, silicon nitride particle and mold
The good and fine and close release layer of adaptation, therefore the good release layer of release property for being capable of forming polycrystalline silicon ingot casting.Before
State the frequency ratio (frequency of the summit of 6~30 μm of frequency/partial size of range of the summit for the range that 0.5~2 μm of partial size of summit
Rate) or less than 1.0,0.95 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less.The summit of partial size smaller
It may be 0.6 μm~1.5 μm of range, in addition, the summit of partial size the greater may be 11 μm~29 μm of range.
It is preferable to use Williamson-Hall formulas by the powder x-ray diffraction of β type silicon nitride for alpha-silicon nitride powders of the invention
The crystal strain for the β type silicon nitride that pattern calculates is 1.5 × 10-4Below.When the crystal strain of β type silicon nitride is the range, i.e.,
Make the melting temperature for further increasing silicon, is also capable of forming the release property, good to the adaptation of mold of polycrystalline silicon ingot casting
Release layer.It could be speculated that by making aforementioned crystalline strain be 1.5 × 10-4Hereinafter, even if being connect for a long time under at higher temperature with molten silicon
Touching, alpha-silicon nitride powders of the invention are also able to maintain that the structural stability of crystal.Consider from the viewpoint, aforementioned crystalline is strained into one
Step preferably 1.2 × 10-4Below, 1.0 × 10 are particularly preferably-4Below.The crystal strain of β type silicon nitride may be 1.5 ×
10-4Below, 1.4 × 10-4Below, 1.2 × 10-4Below, 1.0 × 10-4Below, 0.8 × 10-4Below, 0.7 × 10-4Below.
The content ratio of the Fe of alpha-silicon nitride powders of the invention is 100ppm or less.When the content ratio of Fe is the range,
It is able to suppress in polycrystalline silicon ingot casting and is mixed into Fe, therefore, can be applied to the finished product of the polycrystalline silicon ingot casting of solar battery purposes
Rate is got higher.The content ratio of Fe is preferably 50ppm or less, 20ppm hereinafter, particularly preferably 10ppm or less.In addition, of the invention
Alpha-silicon nitride powders Al content ratio be 100ppm or less.When the content ratio of Al is the range, it is able to suppress in polycrystalline
Al is mixed into silicon ingot casting, therefore, the yield rate that can be applied to the polycrystalline silicon ingot casting of solar battery purposes is got higher.Al's contains
Ratio is preferably 50ppm or less, 20ppm hereinafter, particularly preferably 10ppm or less.In addition, the metal impurities in addition to Fe and Al
Content ratio add up to 100ppm or less.When the content ratio of metal impurities in addition to Fe and Al is the range, it can press down
The metal impurities being mixed into addition to Fe and Al in polycrystalline silicon ingot casting are made, therefore, can be applied to the more of solar battery purposes
The yield rate of crystal silicon ingot casting is got higher.The content ratio of metal impurities in addition to Fe and Al be preferably 50ppm or less, 20ppm with
Under, particularly preferably 10ppm or less.
(polycrystalline silicon ingot casting release agent)
Polycrystalline silicon ingot casting of the invention release agent includes alpha-silicon nitride powders of the invention.Polycrystalline silicon ingot casting of the invention is used
In release agent, alpha-silicon nitride powders of the invention are principal component, also may include the ingredient other than silicon nitride, but can also be with
Only it is made of alpha-silicon nitride powders of the invention.
(manufacturing method of polycrystalline silicon ingot casting)
The manufacturing method of polycrystalline silicon ingot casting of the invention is illustrated below.The manufacturer of polycrystalline silicon ingot casting of the invention
Method is characterized in that, is the manufacture for making the polycrystalline silicon ingot casting of the molten silicon being contained in mold solidification (especially unidirectional solidification)
Method, as aforementioned mold, using with mold that alpha-silicon nitride powders of the invention are coated on the contact surface of aforementioned melt silicon.
(manufacturing methods of alpha-silicon nitride powders)
An example of the manufacturing method of alpha-silicon nitride powders of the invention is illustrated below.For silicon nitride powder of the invention
End, for example, synthesizing nitridation by the combustion synthesis method using the associated self-heating of the combustion reaction with silicon and propagation phenomenon
In silicon, silicon nitride combustion synthesis process, using specific manufacturing condition, specifically, with specific in raw material Si powder
Ratio mixed nitride Si powder as diluent, the metal impurities of the Si powder of raw material and the alpha-silicon nitride powders as diluent
Content ratio it is few, reduce the packed density of the mixture of Si powder and alpha-silicon nitride powders, carry out combustion reaction, make anti-crushing strong
Small combustion product is spent, it is small using size reduction energy and be not easy to be mixed into the method for metal impurities and be adjusted to specifically to crush item
Part crushes come the combustion product small to obtained crushing strength, and thereby, it is possible to manufacture the content ratio with metal impurities
Less, the content ratio of β type silicon nitride is big, has that specific specific surface area and particle diameter distribution, crystallite diameter are big in the present invention and tie
Crystalline substance such as should become smaller at the alpha-silicon nitride powders of features.Hereinafter, an example to the manufacturing method is specifically described.
The preparation section > of < mixed raw material powder
Firstly, Si powder is mixed with the alpha-silicon nitride powders as diluent, mixed raw material powder is prepared.Conbustion synthesis is anti-
It should be 1800 DEG C or more of high temperature, therefore, melting/welding of silicon occur in the part that combustion reaction occurs sometimes.For inhibition
The purpose of the situation, it is preferred that in the range of not interfering the self propagation of combustion reaction, silicon nitride is added in raw material powder
Powder is as diluent.The adding rate of diluent be usually 10~50 mass % (silicon: the mass ratio of silicon nitride be 90:10~50:
It 50), and then is 15~40 mass %.In addition, the ratio of the β type silicon nitride of the combustion product obtained in adjustment combustion synthesis reaction
On the basis of example, NH can also be added4Cl, NaCl etc..These additives have reduced by sensible heat, latent heat and the endothermic reaction
The effect of reaction temperature.Here, the content ratio, the content ratio of Al of Fe in the mixed raw material powder obtained, except Fe and Al with
The content ratio of outer metal impurities is preferably set to 100ppm or less and then 50ppm or less, 10ppm or less respectively.Therefore, silicon
Powder, diluent alpha-silicon nitride powders it is preferable to use the powder of the few high-purity of the content ratio of metal impurities.In addition, raw material
The position that inner surface and blending agent of mixing vessel used in the mixing of powder etc. are contacted with raw material powder is preferably Al
And the raw material of the few nonmetallic system of content ratio of Fe etc..The mixed method of raw material powder is not particularly limited, for example, by using
In the case where ball milling mixing, the inner surface of mixing vessel is preferably made of resin, and the outer surface of blending agent is preferably silicon nitride system.
In addition, the heap density of mixed raw material powder is preferably smaller than 0.5g/cm3.In order to make the heap density of mixed raw material powder be less than 0.5g/
cm3, it is preferable to use heap density is 0.45g/cm3Si powder below is as raw material powder.The heap density of mixed raw material powder is less than
0.5g/cm3When, it is easy to make the crushing strength of block-like combustion product obtained in aftermentioned < combustion synthesis reaction process >
4MPa or less.
< combustion synthesis reaction process >
Then, the mixed raw material powder made burns in nitrogen containing atmosphere, makes the block-like combustion formed by silicon nitride
Burn product.For example, mixed raw material powder is contained in the containers such as graphite together with igniting agent, in combustion synthesis reaction device
It is interior to light igniting agent, cause the nitridation reaction of the silicon in mixed raw material powder by the nitridation combustion heat of igniting agent, keeps this anti-
It answers autobiography to cast to whole silicon to completion of combustion synthetic reaction, obtains the block-like combustion product formed by silicon nitride.
Here, the combustion product obtained preferably its crushing strength is 4MPa or less.The crushing strength of combustion product is 4MPa
When following, in crushing/classification process > of aftermentioned < combustion product, even if without metal impurities be mixed into become it is more or
The crystallinity of alpha-silicon nitride powders reduces the big crushing of such size reduction energy, can also be readily derived the specific specific surface of the present invention
There are two the alpha-silicon nitride powders of the size distribution of summit for product or tool.
The crushing of < combustion product/classification process >
Then, coarse crushing is carried out to obtained block-like combustion product.The crushing means of coarse crushing are not particularly limited, and make
For crushing medium, it is preferable to use the raw material of the nonmetallic system of the few hard of the content ratio of Al and Fe etc., further preferably make
With the crushing medium of silicon nitride.Since combustion product is bulk, it is efficient for crush using kibbler roll, as roller
Formula crusher is preferably provided with the roller made of ceramics such as silicon nitride.
Alpha-silicon nitride powders obtained from the coarse crushing as above are sieved, especially coarse particle etc. is removed.It crosses
The few nonmetallic system of the content ratio of sieve preferably Al and Fe used etc. is sieved, is preferably made of resin.
Then, Crushing of Ultrafine is carried out to the alpha-silicon nitride powders as obtained from coarse crushing.Fine means do not limit especially
Crushing that is fixed, being carried out preferably by vibromill.When being crushed using vibromill, the inner surface of the cylinder of vibromill and mixing
The position that medium etc. is contacted with raw material powder is preferably the raw material of the few nonmetallic system of the content ratio of Al and Fe etc..Cylinder it is interior
Surface is preferably made of resin, and blending agent is preferably silicon nitride system.By be suitable for adjust vibromill condition (amplitude, vibration number,
Grinding time), the peak of specific surface area, two peaks in the curve of frequency distribution measured by size distribution can be adjusted
Top and their frequency ratio.It is preferred that under conditions of energy of rupture becomes smaller, under conditions of such as vibration number, grinding time are short into
Row Crushing of Ultrafine.
As described above, alpha-silicon nitride powders of the invention are manufactured preferably by the manufacturing method of following alpha-silicon nitride powders:
Si powder is mixed with the alpha-silicon nitride powders as diluent, obtained mixed raw material powder is filled into container, benefit is passed through
Aforementioned Si powder is set to burn with the combustion synthesis method of the self-heating and propagation phenomenon associated with combustion reaction, and the burning to obtaining
Product is crushed, and in the manufacturing method, the content ratio of Fe of aforementioned mixed raw material powder, the content ratio of Al and removes Fe
Content ratio with the metal impurities other than Al be respectively 100ppm hereinafter, and heap density be less than 0.5g/cm3, further preferably
The crushing strength of previous combustion product is 4MPa hereinafter, using silicon nitride particularly preferably in the crushing of previous combustion product
Crushing medium.
< mixes the process > of the different powder of average grain diameter
Alpha-silicon nitride powders of the invention can be by carrying out by combustion product coarse crushing and under the conditions of energy of rupture is lesser
Crushing of Ultrafine and obtain, can also be obtained by the different alpha-silicon nitride powders etc. of mixing average grain diameter.For example, it is also possible to by mixed
Close combustion product coarse crushing and alpha-silicon nitride powders obtained from being classified and carry out to fine alpha-silicon nitride powders or
The alpha-silicon nitride powders etc. of granularity are classified and had adjusted after Crushing of Ultrafine, to obtain.In this case, by being suitable for adjusting
Condition, the blending ratio of classification etc. after the condition of classification after coarse crushing, fine condition and Crushing of Ultrafine, can adjust ratio
Surface area, measured as size distribution obtained from two peaks in curve of frequency distribution summit and their frequency ratio.
In addition, being classified and being adjusted by alpha-silicon nitride powders obtained from combustion product coarse crushing and classification, after Crushing of Ultrafine as mixing
It has saved the alpha-silicon nitride powders of granularity or the alpha-silicon nitride powders and well known nitrogen of granularity is classified and had adjusted after Crushing of Ultrafine
SiClx powder can also adjust specific surface area, summit and their frequency ratio.
Embodiment
Being exemplified below concrete example, the present invention will be described in more detail.
Alpha-silicon nitride powders of the invention, the Si powder, raw material mixed powder end and the combustion product that use as raw material powder
The evaluation of the release property of physical property measurement and polycrystalline silicon ingot casting when alpha-silicon nitride powders of the invention to be used for the release agent of mold
It is carried out using the following method.
(the measuring method and specific surface area equivalent diameter D of the specific surface area of alpha-silicon nitride powdersBETCalculation method)
The specific surface area of alpha-silicon nitride powders of the invention uses Mountech corporation Macsorb, inhales using based on nitrogen
Attached 1 method of BET is measured and finds out.
In addition, specific surface area equivalent diameter DBETAssume that the whole particles for constituting powder are the ball of same diameter, under utilization
State what formula (1) was found out.
DBET=6/ (ρS×S)···(1)
Here, ρS(pass through α-Si for the real density of silicon nitride3N4Real density 3186kg/m3、β-Si3N4Real density
3192kg/m3, α phase and β phase ratio calculate true average densities, as real density.), S be specific surface area (m2/g)。
(measuring method of the ratio of the β type silicon nitride of alpha-silicon nitride powders)
The ratio of the β type alpha-silicon nitride powders of alpha-silicon nitride powders of the invention calculates as follows.For silicon nitride powder of the invention
End utilizes the range with 0.02 ° of step-length at 15~80 ° of the angle of diffraction (2 θ) using the target and graphite monochromator formed by the pipe of copper
The timing step scan method for carrying out step-scan to X-ray detector carries out X-ray diffraction measure.Alpha-silicon nitride powders include to denitrogenate
In the case where ingredient other than SiClx, the peak of these ingredients is compared with the corresponding peak of the standard sample of these ingredients, by
This can find out the ratio of these ingredients.It is true by obtained powder X-ray diffraction pattern in following all examples and comparative example
Recognize alpha-silicon nitride powders of the invention to be only made of alpha-form si nitride and β type silicon nitride.In turn, the β of alpha-silicon nitride powders of the invention
The ratio of type silicon nitride utilizes G.P.Gazzara and D.P.Messier, " Determination of Phase Content
Of Si3N4 by X-ray Diffraction Analysis ", Am.Ceram.Soc.Bull., 56 [9] 777-80 (1977)
The method of the Gazzara&Messier of middle record calculates.
(the crystallite diameter D of β type silicon nitrideCAnd the measuring method of crystal strain)
The crystallite diameter D of the β type silicon nitride of alpha-silicon nitride powders of the inventionCAnd crystal strain is measured as follows.For
Alpha-silicon nitride powders of the invention are utilized using the target and graphite monochromator formed by the pipe of copper with 0.02 ° of step-length in the angle of diffraction (2
θ) the timing step scan method that 15~80 ° of range carries out step-scan to X-ray detector carries out X-ray diffraction measure.By
The X-ray diffraction pattern of obtained alpha-silicon nitride powders of the invention calculates (101), (110), (200), (201) of β type silicon nitride
And the respective integral breadth in (210) face, aforementioned integral width is substituted into the Williamson-Hall formula of following formula (1).Will under
" the 2sin θ/λ " for stating formula (2) maps as x-axis, " β cos θ/λ " as y-axis, using least square method, finds out by this
The intercept and slope for the straight line that Williamson-Hall formula obtains.Then, the crystallite for calculating β type silicon nitride by aforementioned intercept is straight
Diameter Dc, also, by the crystal strain of aforementioned slope calculating β type silicon nitride.
β cos θ/λ=η × (2sin θ/λ)+(1/Dc) (2)
(β: integral breadth (rad), θ: Bragg angle (rad), η: crystal strain, λ: wavelength (nm), the Dc of x-ray source: micro-
Brilliant diameter (nm))
(size distribution of alpha-silicon nitride powders and the measuring method of summit)
The size distribution of the Si powder used in alpha-silicon nitride powders of the invention, the present invention as raw material is surveyed as follows
It is fixed.Aforementioned powder is put into 0.2 mass % aqueous solution of calgon, using in the stainless steel for being equipped with diameter 26mm
The ultrasonic homogenizer of heart cone carries out 6 minutes decentralized processings with the output power of 300W, prepares weak solution, as measurement sample.Make
With laser diffraction/scattering formula particle size distribution analyzer (Nikkiso Company Limited MICROTRAC MT3000) to measurement sample
Size distribution be measured, obtain volume reference size distribution curve and its data.By obtained size distribution curve and
Its data finds out the partial size and frequency (volume %) of the summit of alpha-silicon nitride powders of the invention.
(alpha-silicon nitride powders, Fe, Al of Si powder and raw material mixed powder end and the metal impurities in addition to Fe and Al contain
The measuring method of ratio)
The Fe of the Si powder and raw material mixed powder end that are used in alpha-silicon nitride powders of the invention, the present invention as raw material and
Al, metal impurities in addition to Fe and Al content ratio be measured as follows.It is mixed into accommodating by hydrofluoric acid and nitric acid
Liquid container in put into above-mentioned powder and cover tightly, which is heated, divides silicon nitride or silicon completely
Solution carries out constant volume to obtained decomposed solution using ultrapure water, as detection liquid.Use SII NanoTechnology Inc. system
ICP-AES (SPS5100 type), by the wavelength detected and its luminous intensity to Fe, Al in detection liquid and in addition to Fe and Al
Metal impurities quantified, calculate the content ratio of Fe, Al and the metal impurities in addition to Fe and Al.
(measuring method of the heap density of mixed raw material powder)
The heap density of mixed raw material powder obtained in the present invention, which utilizes, is based on the JIS R1628 " heap of fine ceramics powder
The method of density measurement method " is found out.
(measuring method of the crushing strength of combustion product)
The crushing strength of combustion product obtained in the present invention is measured as follows.Spontaneous combustion product cuts 5 side lengths
The cube of 10mm, as measurement sample.Using hand crushing strength measurement device (Aikoh Engineering Co.,
Ltd system, MODEL-1334 type) the aforementioned crushing strength for measuring sample of measurement.Load is applied to the measurement sample for being placed in pedestal,
Compression test is carried out, crushing strength is calculated by the maximum load measured.The crushing strength of combustion product obtained in the present invention is adopted
The average value of the crushing strength of sample is measured with 5.
(evaluation method of the release property of polycrystalline silicon ingot casting)
In the present invention, uses and be coated with the mold that alpha-silicon nitride powders of the invention make as release agent, progress polysilicon
The unidirectional solidification of ingot casting is tested, and polycrystalline silicon ingot casting is demoulded from mold, evaluates alpha-silicon nitride powders of the invention as follows.By polysilicon
Ingot casting can demould from mold and be denoted as zero the case where not confirming the attachment of release layer on polycrystalline silicon ingot casting, and polysilicon is cast
Ingot can demould from mold but be denoted as △ the case where confirming the attachment of release layer on polycrystalline silicon ingot casting, by polycrystalline silicon ingot casting
Cannot be demoulded from mold or allow to demoulding, polycrystalline silicon ingot casting also cracks or the case where notch be denoted as ×.
(measuring methods of metal impurities contained in polycrystalline silicon ingot casting)
Following operation measures Fe, Al contained in the polycrystalline silicon ingot casting obtained in unidirectional solidification experiment and removes Fe and Al
Metal impurities in addition.It is divided into two with the polycrystalline silicon ingot casting that the section mode parallel relative to solidification direction will obtain,
On the central axis of the section, using up the position of 1cm utilizes flight time secondary ion matter as locating from bottom
Spectrometry (ULVAC-PHI, Inc. system (TRIFT V nano TOF type)) carries out surface analysis.By Fe, Al and in addition to Fe and Al
Metal impurities second order ms standardization secondary ion intensity be 1 × 10-4Above situation, which is denoted as, to be detected, will be less than 1
×10-4The case where be denoted as and be not detected.Here, standardization secondary ion intensity refer to by each mass spectrographic secondary ion intensity divided by
Value obtained from all mass spectrographic secondary ion intensity detected.
(embodiment 1-1)
D50 is 4.0 μm, heap density is 0.40g/cm3, Fe content ratio be 3ppm, Al content ratio be 4ppm,
The content ratio of metal impurities in addition to Fe and Al is in the Si powder of 3ppm, with the adding rate of silicon nitride for 20 mass %
The mode of (silicon: the mass ratio of silicon nitride is 80:20) adds the alpha-silicon nitride powders (Ube Industries, Ltd as diluent
System, product name " the SN-E10 " (content ratio of Fe: the content ratio of 9ppm, Al: 2ppm, the metal impurities in addition to Fe and Al
Content ratio: 4ppm)), as raw material powder.Aforementioned raw material powder is contained in filled with silicon nitride ball, inner wall
In the cylinder for having carried out the nylon of liner with carbamate, using intermittent vibromill with vibration number 1200cpm, amplitude 8mm
Mixing 0.5 hour, obtains mixed raw material powder.
Combustion synthesis reaction device 1 used in the combustion synthesis reaction of silicon in the present embodiment is shown in Fig. 1.It will mixing
It is 200 × 400mm, depth 30mm, with a thickness of 10mm that mixed raw material powder 2 obtained from aforementioned raw material powder, which is contained in bottom surface,
Rectangular casket shape graphite container 3 in.At this point, the heap density of mixed raw material powder is 0.45g/cm3.By titanium powder and carbon dust
End is with titanium: the mass ratio that carbon is 4:1 mixes, and is formed, prepares igniting agent 4 used in combustion synthesis reaction, by igniting agent 4
It is positioned on mixed raw material powder 2.Then, the graphite container 3 for accommodating mixed raw material powder 2 and igniting agent 4 is contained in
In the resistance to pressure container 6 for having the carbon heater 5 of igniting agent heating, so that carbon heater 5 is located at the surface of igniting agent 4.
Using vacuum pump 7 to being de-gassed in resistance to pressure container 6 after, is imported by nitrogen gas tank 8 in Xiang Qianshu reaction vessel
Nitrogen makes atmosphere pressures 0.6MPa.Then, it is powered to carbon heater 5, igniting agent 4 is heated, aforementioned mixed raw material is made
Powder point, which is fought, starts combustion synthesis reaction.In combustion synthesis reaction, the nitrogen atmosphere pressure almost constant of resistance to pressure container 6 is
0.6MPa.The inside of resistance to pressure container 6 from sight glass 9, combustion synthesis reaction for about terminating after twenty minutes.React end
Afterwards, graphite container 3 is taken out from resistance to pressure container 6, recycles block-like combustion product.
The part around igniting agent is removed from obtained combustion product, and remainder has been subjected to amino using inner surface
Formic acid esters is coated with and the kibbler roll for having silicon nitride roller carries out coarse crushing, is carried out with 100 μm of mesh of nylon system sieve
Sieve recycles the powder under sieve.By obtained powder be contained in filled with silicon nitride ball, inner wall using carbamate into
It has gone in the cylinder for aoxidizing aluminum of liner, using intermittent vibromill, has been carried out 0.25 hour with vibration number 1200cpm, amplitude 8mm
Crushing of Ultrafine obtains the alpha-silicon nitride powders of embodiment 1-1.When being crushed using intermittent vibromill, as grinding aid, to powder
The ethyl alcohol of 1 mass % of end addition.
By the physics value of Si powder used in raw material powder in embodiment 1-1 and diluent, the object of mixed raw material powder
Property value and the crushing strength of combustion product are shown in table 1, also, the physics value of alpha-silicon nitride powders is shown in table 2.
[table 1]
[table 2]
The alpha-silicon nitride powders of embodiment 1-1 are implemented as follows as the evaluation of the release agent of polycrystalline silicon ingot casting casting mold.
The alpha-silicon nitride powders of embodiment 1-1 are contained in the polyethylene container that can be covered tightly, water are added, thus with nitrogen
The mixing ratio of SiClx powder becomes the mode of 20 mass % to prepare.Nitrogen is put into the container for accommodating alpha-silicon nitride powders and water
SiClx ball simultaneously covers tightly, and obtains silicon nitride slurry using intermittent vibromill with amplitude 5mm, vibration number 1780cpm mixing 5 minutes
Material.
The Silicon Nitride spraying coating of obtained embodiment 1-1 is being preheating to 90 DEG C and the porosity 16%, bottom surface are
Then the square of 100mm, the inner surface of the quartz crucible of depth 100mm are dried 15 hours at 90 DEG C.At this time de-
Mold layer with a thickness of about 0.2mm.In turn, it using air atmosphere furnace, is kept for 3 hours, is heated at 1100 DEG C in air
Processing, obtains the polycrystalline silicon ingot casting casting mold that release layer applies the alpha-silicon nitride powders of embodiment 1-1.
Purity 7N, the silicon particle 300g having a size of 2~5mm are filled into aforementioned mold, are contained in Bu Liziman furnace.?
The argon gas circulation of atmospheric pressure is lower will to be warming up to 1500 DEG C with 5 hours in furnace, melt silicon particle.It is kept for 24 hours at 1500 DEG C
Later, aforementioned mold was reduced with 50mm/ hours reduction speed, makes molten silicon unidirectional solidification, and then be cooled to room temperature.In addition,
The polycrystalline silicon ingot casting casting mold for making 1 embodiment 1-1 again using the mold, and will keep temperature to be changed to 1550 DEG C,
In addition to this, same method progress unidirectional solidification experiment is tested using with aforementioned unidirectional solidification.
Polycrystalline silicon ingot casting is demoulded from the aforementioned mold of taking-up, is utilized " evaluation method of polycrystalline silicon ingot casting casting mold "
The polycrystalline silicon ingot casting casting mold and polycrystalline silicon ingot casting of the method evaluation embodiment 1-1 of middle explanation.It the results are shown in table 3.
[table 3]
(embodiment 1-2~1-6)
By the fine time of embodiment 1-2~1-6 be successively set as from embodiment 1-2 0.30 hour, 1.50 hours,
2.50 hours, 4.00 hours, 6.00 hours, it is in addition to this, same as embodiment 1-1 to operate, obtain embodiment 1-2~1-6's
Alpha-silicon nitride powders.Then, the alpha-silicon nitride powders of each embodiment used are as release agent, using same as embodiment 1-1
Method make 2 polycrystalline silicon ingot casting casting molds respectively.In embodiments, using these molds, utilization and embodiment
The same method of 1-1 carries out the unidirectional solidification under two kinds of in-furnace temperatures same with embodiment 1-1 and tests, using with embodiment 1-
1 same method evaluates polycrystalline silicon ingot casting casting mold.
(embodiment 1-7)
The alpha-silicon nitride powders of embodiment 1-4 are sieved by the nylon system that mesh is 40 μm, the powder under recycling sieve obtains reality
Apply the alpha-silicon nitride powders of a 1-7.Then, the alpha-silicon nitride powders of the embodiment 1-7 used as release agent, using with implementation
The same method of example 1-1 makes 2 polycrystalline silicon ingot casting casting molds.Using these molds, using same as embodiment 1-1
Method carries out the unidirectional solidification experiment under 1500 DEG C and 1525 DEG C of two kinds of in-furnace temperatures, using with the same side embodiment 1-1
Method evaluates polycrystalline silicon ingot casting casting mold.
(embodiment 1-8)
In raw material powder, as additive, ammonium chloride (He Guangchun medicine system, purity 99.9%) 12.4 matter are further added
% (so that the mass ratio of the mixed-powder and ammonium chloride of silicon and silicon nitride is 87.6:12.4) is measured, in addition to this, with embodiment 1-
3 same operations, make the alpha-silicon nitride powders of embodiment 1-8.Then, the alpha-silicon nitride powders of the embodiment 1-8 used as
Release agent makes 2 polycrystalline silicon ingot casting casting molds using method same as embodiment 1-1.Using these molds, utilize
Same as embodiment 1-1 method carries out the unidirectional solidification under two kinds of in-furnace temperatures same with embodiment 1-1 and tests, using with
The same method of embodiment 1-1 evaluates polycrystalline silicon ingot casting casting mold.
(embodiment 1-9)
It, will using air classifier (Nisshin Engineering Inc. trade name " Turbo classifier ")
Separation is set as 2 μm, is classified to the alpha-silicon nitride powders of embodiment 1-2, obtains partial size big alpha-silicon nitride powders and partial size
Small alpha-silicon nitride powders.The big alpha-silicon nitride powders of partial size are recycled, (space portion is emerging with commercially available alpha-silicon nitride powders by the alpha-silicon nitride powders
Produce Co. Ltd. system, product name " the SN-E10 " (content ratio of Fe: the content ratio of 9ppm, Al: 2ppm, in addition to Fe and Al
Metal impurities content ratio: 4ppm)) with the ratio of mass ratio 1:1, applied using inner surface using carbamate
The V-Mixer of cloth mix within 0.17 hour.Then, the alpha-silicon nitride powders of the embodiment 1-9 used as release agent,
2 polycrystalline silicon ingot casting casting molds are made using method same as embodiment 1-1.Using these molds, using with implementation
The same method of example 1-1 carries out the unidirectional solidification experiment under two kinds of in-furnace temperatures same as embodiment 1-1, utilization and embodiment
The same method of 1-1 evaluates polycrystalline silicon ingot casting casting mold.
(embodiment 1-10)
Jet mill (the Nisshin for the liner for having silicon nitride in kiss portion will be used after coarse crushing
Engineering Inc. SJ-1500 type) with necessary air capacity 3.0m3/ minute, raw material feed speed 250g/ minutes or so
Condition crushed obtained from alpha-silicon nitride powders and commercially available alpha-silicon nitride powders (Ube Industries, Ltd's system, product name
" SN-E10 " (content ratio of Fe: the content ratio of 9ppm, Al: 2ppm, metal impurities in addition to Fe and Al containing than
Example: 4ppm)) with the ratio of mass ratio 2:1, it is carried out using inner surface using the V-Mixer that carbamate is coated with
It mixes within 0.17 hour, obtains the alpha-silicon nitride powders of embodiment 1-10.Then, using the alpha-silicon nitride powders of obtained embodiment 1-10
As release agent, 2 polycrystalline silicon ingot casting casting molds are made using method same as embodiment 1-1.Using these molds,
It carries out the unidirectional solidification under two kinds of in-furnace temperatures same as embodiment 1-1 using method same as embodiment 1-1 to test, benefit
Polycrystalline silicon ingot casting casting mold is evaluated with method same as embodiment 1-1.
(embodiment 1-11)
Jet mill (the Nisshin for the liner for having silicon nitride in kiss portion will be used after coarse crushing
Engineering Inc. SJ-1500 type) with necessary air capacity 3.0m3/ minute, raw material feed speed 250g/ minutes or so
Condition crushed obtained from alpha-silicon nitride powders and commercially available alpha-silicon nitride powders (Ube Industries, Ltd's system, product name
" SN-E10 " (content ratio of Fe: the content ratio of 9ppm, Al: 2ppm, metal impurities in addition to Fe and Al containing than
Example: 4ppm)) with the ratio of mass ratio 1:1, it is carried out using inner surface using the V-Mixer that carbamate is coated with
It mixes within 0.17 hour, obtains the alpha-silicon nitride powders of embodiment 1-11.Then, using the alpha-silicon nitride powders of obtained embodiment 1-11
As release agent, 2 polycrystalline silicon ingot casting casting molds are made using method same as embodiment 1-1.Using these molds,
It carries out the unidirectional solidification under two kinds of in-furnace temperatures same as embodiment 1-7 using method same as embodiment 1-1 to test, benefit
Polycrystalline silicon ingot casting casting mold is evaluated with method same as embodiment 1-1.
(comparative example 1-1,1-2)
The fine time is set as in comparative example 1-1 0.16 hour, 12.00 hours in comparative example 1-2, in addition to this,
It is same as embodiment 1-1 to operate, obtain the alpha-silicon nitride powders of comparative example 1-1 and 1-2.As shown in table 2, the nitridation of comparative example 1-1
Si powder is that specific surface area is smaller and be 1.8m2The powder of/g, the alpha-silicon nitride powders of comparative example 1-2 are that specific surface area is larger and be
14.8m2The powder of/g.Then, the alpha-silicon nitride powders of each comparative example used as release agent, using with embodiment 1-1
Same method makes 1 polycrystalline silicon ingot casting casting mold.In each comparative example, using the mold, using same with embodiment 1-1
The method evaluation polycrystalline silicon ingot casting casting mold and silicon ingot casting of sample.
(comparative example 1-3)
In raw material powder, as additive, ammonium chloride (He Guangchun medicine system, purity 99.9%) 16.7 matter are further added
% (so that the mass ratio of the mixed-powder and ammonium chloride of silicon and silicon nitride is 83.3:16.7) is measured, in addition to this, with embodiment 1-
3 same operations, obtain the alpha-silicon nitride powders of comparative example 1-3.The alpha-silicon nitride powders of comparative example 1-3 are as shown in table 2, nitrogenize for β type
The powder that the ratio of silicon is less and is 46%.Then, the alpha-silicon nitride powders of the comparative example 1-3 used are sharp as release agent
1 polycrystalline silicon ingot casting casting mold is made with method same as embodiment 1-1.Using the mold, using with embodiment 1-1
Same method evaluation polycrystalline silicon ingot casting casting mold and silicon ingot casting.
(comparative example 1-4, comparative example 1-5)
By D50 be 2.5 μm, heap density is 0.26g/cm3, Fe content ratio be 2ppm, Al content ratio be 3ppm,
The content ratio of metal impurities in addition to Fe and Al is that the Si powder of 3ppm is filled in the mold of internal diameter 30mm, with
1500kg/cm2Pressure carry out uniaxial molding, obtain the uniaxial formed body of Si powder.Aforementioned formed body is filled in graphite system
It in container, is then accommodated in intermittent nitriding furnace, after being replaced as nitrogen atmosphere in furnace, is warming up to 1450 under nitrogen atmosphere
DEG C, it is kept for 3 hours.After being cooled to room temperature, nitridation product is taken out.Carbamate coating, tool have been carried out using inner surface
The kibbler roll of standby silicon nitride roller carries out coarse crushing to obtained nitridation product, is sieved using the nylon system that mesh is 100 μm
It is sieved, the powder under recycling sieve.Then, aforementioned powder is contained in and utilizes amino first filled with silicon nitride ball, inner surface
Acid esters has carried out in the cylinder of oxidation aluminum of liner, using intermittent vibromill with the condition of vibration number 1200cpm, amplitude 8mm
Carry out Crushing of Ultrafine.The fine time is set as in comparative example 1-4 0.33 hour, 2.00 hours in comparative example 1-5, obtains each comparison
The alpha-silicon nitride powders of example.The nitrogen of the comparative example 1-4 and comparative example 1-5 that are obtained using the direct nitridation method for being not belonging to combustion synthesis method
SiClx powder is as shown in table 2, respectively crystallite diameter DcIt is smaller and be 50nm and 45nm, crystal strain is larger and is 2.55 × 10-4And 2.20 × 10-4、DBET/DcPowder that is larger and being 11.0 and 4.6.Then, using the silicon nitride powder of obtained each comparative example
End is used as release agent, makes 1 polycrystalline silicon ingot casting casting mold using method same as embodiment 1-1.In each comparative example,
Using the mold, polycrystalline silicon ingot casting casting mold and silicon ingot casting are evaluated using method same as embodiment 1-1.
(comparative example 1-6)
It, will using air classifier (Nisshin Engineering Inc. trade name " Turbo classifier ")
Separation is set as 1 μm, is classified to the alpha-silicon nitride powders of embodiment 1-4, obtains the big alpha-silicon nitride powders of partial size and partial size is small
Alpha-silicon nitride powders.The big alpha-silicon nitride powders of partial size are recycled, the alpha-silicon nitride powders of comparative example 1-6 are obtained.The nitridation of comparative example 1-6
Si powder is as shown in table 2, is that the summit of partial size smaller is larger and be 3.5 μm of powder.Then, using obtained comparative example 1-
6 alpha-silicon nitride powders make 1 polycrystalline silicon ingot casting casting mold as release agent, using method same as embodiment 1-1.
Using the mold, polycrystalline silicon ingot casting casting mold and silicon ingot casting are evaluated using method same as embodiment 1-1.
(comparative example 1-7)
The fine time is set as 0.2 hour, it is in addition to this, same as embodiment 1-1 to operate, obtain silicon nitride powder
End.Using air classifier (Nisshin Engineering Inc. trade name " Turbo classifier "), will demarcate
Point is set as 2 μm, is classified to obtained alpha-silicon nitride powders, obtains the big alpha-silicon nitride powders of partial size and the small silicon nitride of partial size
Powder.The big alpha-silicon nitride powders of partial size are recycled, by the alpha-silicon nitride powders and commercially available alpha-silicon nitride powders (Ube Industries, Ltd
System, product name " the SN-E10 " (content ratio of Fe: the content ratio of 9ppm, Al: 2ppm, the metal impurities in addition to Fe and Al
Content ratio: 4ppm)) with the ratio of mass ratio 1:1, the V-type being coated with using inner surface using carbamate is mixed
Conjunction machine mix within 0.17 hour, obtains the alpha-silicon nitride powders of comparative example 1-7.The alpha-silicon nitride powders of comparative example 1-7 such as 2 institute of table
Show, is that the summit of partial size smaller is larger and be 32.3 μm of powder.Then, using the silicon nitride powder of obtained comparative example 1-8
End is used as release agent, makes 1 polycrystalline silicon ingot casting casting mold using method same as embodiment 1-1.Using the mold,
Polycrystalline silicon ingot casting casting mold and silicon ingot casting are evaluated using method same as embodiment 1-1.
(comparative example 1-8)
It, will using air classifier (Nisshin Engineering Inc. trade name " Turbo classifier ")
Separation is set as 12 μm, is classified to the alpha-silicon nitride powders of embodiment 1-3, obtains partial size big alpha-silicon nitride powders and partial size
Small alpha-silicon nitride powders.The small alpha-silicon nitride powders of partial size are recycled, the alpha-silicon nitride powders of comparative example 1-8 are obtained.The nitrogen of comparative example 1-8
SiClx powder is as shown in table 2, be partial size smaller summit frequency and partial size the greater summit frequency ratio it is larger and
For 1.54 powder.Then, the alpha-silicon nitride powders of the comparative example 1-8 used are as release agent, using same with embodiment 1-1
The method of sample makes 1 polycrystalline silicon ingot casting casting mold.Using the mold, evaluated using method same as embodiment 1-1
Polycrystalline silicon ingot casting casting mold and silicon ingot casting.
(comparative example 1-9)
It, will using air classifier (Nisshin Engineering Inc. trade name " Turbo classifier ")
Separation is set as 2 μm, is classified to the alpha-silicon nitride powders of comparative example 1-8, obtains partial size big alpha-silicon nitride powders and partial size
Small alpha-silicon nitride powders.The small alpha-silicon nitride powders of partial size are recycled, the alpha-silicon nitride powders of comparative example 1-9 are obtained.The nitrogen of comparative example 1-9
SiClx powder is the powder that the summit of partial size is 1.Then, the alpha-silicon nitride powders of the comparative example 1-9 used as demoulding
Agent makes 1 polycrystalline silicon ingot casting casting mold using method same as embodiment 1-1.Using the mold, using with implementation
The same method evaluation polycrystalline silicon ingot casting casting mold of example 1-1 and silicon ingot casting.
(comparative example 1-10~1-12)
Use powder shown in table 1 as raw material Si powder, it is in addition to this, same as embodiment 1-4 to operate, compared
The alpha-silicon nitride powders of example 1-10~1-12.The alpha-silicon nitride powders of comparative example 1-10~1-12 is the content of Fe, the contents of Al and remove
The content of metal impurities other than Fe, Al is more and the powder of respectively 159ppm, 140ppm and 134ppm.Then, it uses
The alpha-silicon nitride powders of the comparative example 1-10~1-12 arrived respectively make 1 as release agent, using method same as embodiment 1-1
Polycrystalline silicon ingot casting casting mold.In each comparative example, using the mold, polycrystalline is evaluated using method same as embodiment 1-1
Silicon ingot casting casting mold and silicon ingot casting.
(comparative example 1-13)
The coarse crushing of combustion product utilizes the micro mist of intermittent vibromill using the kibbler roll for having oxidation aluminum roller
The broken cylinder using the oxidation aluminum filled with oxidation aluminum ball, in addition to this, same as embodiment 1-4 to operate, comparison example
The alpha-silicon nitride powders of 1-13.The alpha-silicon nitride powders of comparative example 1-13 are content, the content of Al and the gold in addition to Fe, Al of Fe
The content of category impurity is more and is the powder of 240ppm, 3700ppm, 129ppm.Then, using obtained comparative example 1-13's
Alpha-silicon nitride powders make 1 polycrystalline silicon ingot casting casting mold as release agent, using method same as embodiment 1-1.Make
With the mold, polycrystalline silicon ingot casting casting mold and silicon ingot casting are evaluated using method same as embodiment 1-1.
By Si powder and additive used in the raw material powder in embodiment 1-2~1-11 and comparative example 1-1~1-13
Physics value, mixed raw material powder physics value and combustion product crushing strength it is shown in table 1, also, by alpha-silicon nitride powders
Physics value is shown in table 2.In addition, by the polycrystalline silicon ingot casting casting mold of embodiment 1-2~1-11 and comparative example 1-1~1-13 and
Polycrystalline silicon ingot casting evaluation result is shown in table 3.
(embodiment 2-1)
Using method described below, the polysilicon with the release layer of the alpha-silicon nitride powders comprising embodiment 1-1 is made
Ingot casting casting mold implements the evaluation of polycrystalline silicon ingot casting casting mold and silicon ingot casting.
The alpha-silicon nitride powders of embodiment 1-1 are contained in the polyethylene container that can be sealed, addition silica is dense
Spend the silicon dioxide gel (chemical company, Japan system, product name " PL-3 ") and water of 20 mass %.At this point, according to by quality ratio
Silicon nitride: silicon dioxide gel: water is that the mode of 20:8:72 is mixed.Then, to accommodating alpha-silicon nitride powders, titanium dioxide
Silicon nitride ball is put into the container of silica solution and water and is sealed, using intermittent vibromill, with amplitude 5mm, vibration number
1780cpm mix within 5 minutes, and Silicon Nitride is obtained.
By the Silicon Nitride spraying coating of obtained embodiment 2-1 be preheating to 90 DEG C, the porosity 16%, bottom surface be
The inner surface of the quartz crucible of the square and depth 100mm of 100mm, it is then, 15 hours dry at 90 DEG C, had
The polycrystalline silicon ingot casting casting mold of the release layer of the standby alpha-silicon nitride powders comprising embodiment 2-1.The thickness of release layer at this time
It is about 0.2mm.
It is same as embodiment 1-1 to operate using the polycrystalline silicon ingot casting casting mold of obtained embodiment 2-1, it carries out single
To solidification experiments, cast using the polycrystalline silicon ingot casting casting mold and silicon of method same as embodiment 1-1 evaluation embodiment 2-1
Ingot.It the results are shown in table 4.
[table 4]
(embodiment 2-2~2-11, comparative example 2-1~2-13)
Using alpha-silicon nitride powders shown in table 4, in addition to this, using method same as embodiment 2-1, silicon nitride is made
Slurry manufactures polycrystalline silicon ingot casting casting mold.It is cast and is used using the polycrystalline silicon ingot casting of obtained each embodiment and each comparative example
Mold, it is same as embodiment 1-1 to operate, unidirectional solidification experiment is carried out, evaluates polysilicon using method same as embodiment 1-1
Ingot casting casting mold and silicon ingot casting.It the results are shown in table 4.
As can be observed from the foregoing, alpha-silicon nitride powders of the invention by carrying out hot place at high temperature after being coated on mold
Reason, can substantially form adaptation and the good release layer of release property in the mould with its own, in addition, by with titanium dioxide
Silica solution is mixed and is coated in the mould, can form adaptation and release property in the mould the heat treatment without high temperature
Good release layer.
Industrial availability
Alpha-silicon nitride powders of the invention as can form and the adaptation of mold and the good demoulding of release property in the mould
Layer release agent be it is useful, especially as the polysilicon that can obtain high quality silicon substrate used for solar batteries with high finished product rate
The release agent of ingot casting is useful.In addition, alpha-silicon nitride powders of the invention can form fine and close release layer and crystallinity is high,
It therefore, is also useful as the raw material for showing high-intensitive silicon nitride sinter at high temperature.
Description of symbols
1 combustion synthesis reaction device
2 mixed raw material powder
3 graphite containers
4 igniting agents
5 carbon heaters
6 resistance to pressure containers
7 vacuum pumps
8 nitrogen gas tanks
9 sight glasses
Claims (8)
1. a kind of alpha-silicon nitride powders, which is characterized in that the specific surface area using BET method measurement is 2m2/ g or more and 13m2/ g with
Under,
The ratio of β type silicon nitride is 50 mass % or more,
Williamson-Hall formula will be used by the micro- of the β type silicon nitride of the powder X-ray diffraction pattern calculating of β type silicon nitride
Brilliant diameter is set as DCWhen, DCFor 150nm or more,
The specific surface area equivalent diameter calculated by the specific surface area is set as DBETWhen, DBET/DC(nm/nm) be 3 hereinafter,
The curve of frequency distribution as obtained from the measurement of the size distribution of the volume reference based on laser diffraction scattering method has two
A peak,
The summit at the peak is in 0.5~2 μm of range and 6~30 μm of range,
The peak of 6~30 μm of frequency/partial size of range of the summit of 0.5~2 μm of frequency ratio, that is, partial size of range of the summit
The frequency on top is 0.1~1.
2. alpha-silicon nitride powders according to claim 1, which is characterized in that nitrogenized using Williamson-Hall formula by β type
The crystal strain for the β type silicon nitride that the powder X-ray diffraction pattern of silicon calculates is 1.5 × 10-4Below.
3. alpha-silicon nitride powders according to claim 1 or 2, which is characterized in that the summit is in 0.5~2 μm of range
With 9~30 μm of range.
4. alpha-silicon nitride powders described in any one of claim 1 to 3, which is characterized in that the ratio of β type silicon nitride is 70
Quality % or more.
5. alpha-silicon nitride powders according to any one of claims 1 to 4, which is characterized in that the specific surface area is 2m2/g
Above and 10m2/ g or less.
6. alpha-silicon nitride powders according to any one of claims 1 to 5, which is characterized in that the content ratio of Fe is
100ppm hereinafter,
The content ratio of Al be 100ppm hereinafter,
The content ratio of metal impurities in addition to Fe and Al adds up to 100ppm or less.
7. a kind of polycrystalline silicon ingot casting release agent, it includes alpha-silicon nitride powders according to any one of claims 1 to 6.
8. a kind of manufacturing method of silicon ingot casting, which is characterized in that it is the silicon ingot casting for solidifying the molten silicon being contained in mold
Manufacturing method, as the mold, using be coated on the contact surface of the molten silicon it is any in claim 1~6
The mold of alpha-silicon nitride powders described in.
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| JP2016-240752 | 2016-12-12 | ||
| JP2016240752 | 2016-12-12 | ||
| PCT/JP2017/044619 WO2018110567A1 (en) | 2016-12-12 | 2017-12-12 | Silicon nitride powder, mold release agent for polycrystalline silicon ingots, and method for producing polycrystalline silicon ingots |
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| CN110049946A true CN110049946A (en) | 2019-07-23 |
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| JP (1) | JP6690735B2 (en) |
| CN (1) | CN110049946A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115702130A (en) * | 2020-06-30 | 2023-02-14 | 株式会社德山 | Silicon nitride sintered substrate |
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| CN109761206A (en) * | 2019-03-18 | 2019-05-17 | 青岛瓷兴新材料有限公司 | A kind of spherical beta silicon nitride powder of high-purity low aluminium, its manufacturing method and application |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011051856A (en) * | 2009-09-03 | 2011-03-17 | Denki Kagaku Kogyo Kk | Method for producing high-purity silicon nitride fine powder |
| JP2012001385A (en) * | 2010-06-16 | 2012-01-05 | Denki Kagaku Kogyo Kk | Silicon nitride powder for mold release agent |
| JP2013071864A (en) * | 2011-09-28 | 2013-04-22 | Denki Kagaku Kogyo Kk | Silicon nitride powder for mold releasing agent, and method for producing the same |
| CN103282307A (en) * | 2010-12-28 | 2013-09-04 | 宇部兴产株式会社 | Polycrystalline silicon ingot casting mold, and silicon nitride powder for mold release material, slurry containing silicon nitride powder for mold release layer and casting release material therefor |
| CN103396170A (en) * | 2013-07-08 | 2013-11-20 | 特变电工新疆新能源股份有限公司 | Preparation method of crucible coating for polycrystalline silicon ingot and crucible |
| JP2014009111A (en) * | 2012-06-28 | 2014-01-20 | Denki Kagaku Kogyo Kk | Silicon nitride powder for mold-releasing agent |
| CN105377756A (en) * | 2013-07-11 | 2016-03-02 | 宇部兴产株式会社 | Silicon nitride powder for mold release agent of casting mold for casting polycrystalline silicon ingot and method for manufacturing silicon nitride powder, slurry containing silicon nitride powder, casting mold for casting polycrystalline silicon ingot and method for manufacturing same, and method for manufacturing polycrystalline silicon ingot cast using casting mold |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3877645B2 (en) * | 2002-06-03 | 2007-02-07 | 電気化学工業株式会社 | Method for producing silicon nitride powder |
| JP6245602B2 (en) * | 2013-10-21 | 2017-12-13 | 国立研究開発法人産業技術総合研究所 | Silicon nitride filler, resin composite, insulating substrate, semiconductor encapsulant, method for producing silicon nitride filler |
| TW201605763A (en) * | 2014-06-16 | 2016-02-16 | Ube Industries | Silicon nitride powder, silicon nitride sintered body and circuit substrate, and production method for said silicon nitride powder |
-
2017
- 2017-12-12 CN CN201780076711.9A patent/CN110049946A/en active Pending
- 2017-12-12 TW TW106143842A patent/TWI657042B/en not_active IP Right Cessation
- 2017-12-12 JP JP2018556701A patent/JP6690735B2/en active Active
- 2017-12-12 WO PCT/JP2017/044619 patent/WO2018110567A1/en active Application Filing
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011051856A (en) * | 2009-09-03 | 2011-03-17 | Denki Kagaku Kogyo Kk | Method for producing high-purity silicon nitride fine powder |
| JP2012001385A (en) * | 2010-06-16 | 2012-01-05 | Denki Kagaku Kogyo Kk | Silicon nitride powder for mold release agent |
| CN103282307A (en) * | 2010-12-28 | 2013-09-04 | 宇部兴产株式会社 | Polycrystalline silicon ingot casting mold, and silicon nitride powder for mold release material, slurry containing silicon nitride powder for mold release layer and casting release material therefor |
| JP2013071864A (en) * | 2011-09-28 | 2013-04-22 | Denki Kagaku Kogyo Kk | Silicon nitride powder for mold releasing agent, and method for producing the same |
| JP2014009111A (en) * | 2012-06-28 | 2014-01-20 | Denki Kagaku Kogyo Kk | Silicon nitride powder for mold-releasing agent |
| CN103396170A (en) * | 2013-07-08 | 2013-11-20 | 特变电工新疆新能源股份有限公司 | Preparation method of crucible coating for polycrystalline silicon ingot and crucible |
| CN105377756A (en) * | 2013-07-11 | 2016-03-02 | 宇部兴产株式会社 | Silicon nitride powder for mold release agent of casting mold for casting polycrystalline silicon ingot and method for manufacturing silicon nitride powder, slurry containing silicon nitride powder, casting mold for casting polycrystalline silicon ingot and method for manufacturing same, and method for manufacturing polycrystalline silicon ingot cast using casting mold |
Non-Patent Citations (2)
| Title |
|---|
| 袁向东等: ""多晶硅铸锭涂层用高纯Ｓｉ3Ｎ4微粉的研究进展与展望"", 《硅酸盐通报》 * |
| 韩至成等: "《太阳能级硅提纯技术与装备》", 31 October 2011, 冶金工业出版社 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115702130A (en) * | 2020-06-30 | 2023-02-14 | 株式会社德山 | Silicon nitride sintered substrate |
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| Publication number | Publication date |
|---|---|
| WO2018110567A1 (en) | 2018-06-21 |
| JP6690735B2 (en) | 2020-04-28 |
| JPWO2018110567A1 (en) | 2019-06-24 |
| TWI657042B (en) | 2019-04-21 |
| TW201829303A (en) | 2018-08-16 |
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