Molding method for silicon powder, silicon block, and use

Abstract

The present application relates to the technical field of single crystal growth. Disclosed are a molding method for silicon powder, a silicon block, and a use. The molding method for silicon powder of the present application comprises: placing a mold loaded with silicon powder under a condition of a first pressure P1 for a first pressure time T1, wherein 50 MPa≤P1≤600 MPa and 7 min≤T1≤15 min, thereby obtaining a silicon block. According to the present application, by means of pressure control, it is easy to remove a molded silicon block from a mold, without breaking and generation of flying dust. It is easy to crush the molded silicon block, the particle size distribution after crushing is easy to control, and the flying dust amount in the crushing process is low. In the present application, the molded silicon block can be directly used for Czochralski single crystal production, and the loading density is increased to 0.18 g / cm3 to 0.25 g / cm3.

Description

Silicon powder molding method, silicon block and application Technical Field

[0001] The present application relates to the field of single crystal growth technology, and in particular to a silicon powder molding method, a silicon block and applications. Background Art

[0002] Since the particle size of native polysilicon powder is small (particle size 0.1μm to 1000μm), its loading density is low, that is, the weight loaded in the same space is small, which directly affects the weight of the crucible before the use of the CZ vertical single crystal furnace. It cannot be used in the process of re-charging (continuous feeding crystal pulling technology) of the CZ vertical single crystal furnace. Technical issues

[0003] The present application provides a silicon powder molding method, silicon blocks and applications, which solve the problem that silicon powder cannot be directly used in the production of Czochralski single crystals. Technical Solutions

[0004] According to the first embodiment of the present application, the silicon powder molding method includes the following steps:

[0005] The mold filled with silicon powder is placed under a first pressure P1 for a first pressure time T1, satisfying 50 MPa≤P1≤600 MPa, 7 min≤T1≤15 min, to obtain a silicon block.

[0006] Optionally, the first pressure P1 condition is achieved by increasing the pressure, and the pressure increasing step includes increasing the pressure to the first pressure P1 at a first pressure increasing rate v1, satisfying 20 MPa / s≤v1≤30 MPa / s.

[0007] Optionally, before the mold filled with silicon powder is placed under the first pressure P1 condition, the mold filled with silicon powder is placed in a closed environment.

[0008] Optionally, the first pressure P1 condition is applied by a pressurized medium, the pressurized medium is a fluid, the mold filled with silicon powder is placed before the first pressure P1 condition, and the mold filled with silicon powder is placed in the cavity;

[0009] The mold and the pressurized medium are separated by the cavity; or the pressurized medium is filled in the cavity, and the mold is in contact with the pressurized medium.

[0010] Optionally, when the mold and the pressurized medium are separated by the cavity, the pressurized medium is liquid; when the pressurized medium is filled in the cavity, the mold is in contact with the pressurized medium, and the pressurized medium is gas.

[0011] Optionally, when the mold and the pressurized medium are separated by the cavity, the interior of the cavity maintains a dry environment, the dry environment temperature range is 20° C. to 25° C., and the humidity range is 40% rh to 50% rh, where rh is relative humidity.

[0012] Optionally, the particle size of the silicon powder is 0.1 μm to 1000 μm.

[0013] Optionally, the mold includes a first surface and a second surface that are opposite to each other, the first surface and the second surface are connected via a third surface, and the first surface and the third surface receive the first pressure P1.

[0014] Optionally, the first surface, the second surface, and the third surface receive the first pressure P1, and a pressure deviation PD applied by the first pressure P1 on the first surface, the second surface, and the third surface satisfies: -5 MPa≤PD≤5 MPa.

[0015] Optionally, the mold includes a cover and a cylinder, the cover seals the cylinder, and the silicon powder is filled in the cylinder.

[0016] Optionally, a protective sleeve is provided on the outer periphery of the cover body, and the protective sleeve is provided on at least a portion of the cover body.

[0017] Optionally, the edge of the cover body includes steps, and the steps surround the cover body.

[0018] Optionally, the mold is made of polyurethane material, and the density ρ0 of the polyurethane material satisfies: 1.00 g / cm 3 ≤ρ0≤1.01g / cm 3 .

[0019] Optionally, the wear rate G of the mold satisfies: G<G0, where G0 is the material loss in g / cm 2 ;

[0020] The G0 satisfies: 0<G0≤0.1.

[0021] Optionally, the mold filled with silicon powder is placed under a second pressure P2 for a second pressure time T2, satisfying 50 MPa≤P2≤200 MPa, 3 min≤T2≤7 min;

[0022] The mold filled with silicon powder is placed under a third pressure P3 for a third pressure time T3, satisfying 200 MPa≤P3≤600 MPa, 4 min≤T3≤8 min.

[0023] Optionally, the mold filled with silicon powder is placed under a fourth pressure condition P4 for a fourth pressure time T4, satisfying 100 MPa≤P4≤600 MPa, 3 min≤T4≤6 min.

[0024] Optionally, after the pressurization process is completed, a first pressure relief process is applied to the mold, and the first pressure relief process includes: reducing the pressure to a fifth pressure P5 for T n Time, meeting: 100MPa≤P5≤100MPa, 1min≤T n ≤2min.

[0025] The silicon block in the second embodiment of the present application is prepared by the above-mentioned preparation method.

[0026] Optionally, the silicon block is crushed to form first particles, and based on the mass of the silicon block, the mass percentage of the first particles to the silicon block is ≥97%, and the particle size D1 of the first particles satisfies: 10 mm ≤ D1.

[0027] Optionally, the silicon block is crushed to form second particles, and based on the mass of the silicon block, the mass percentage of the second particles in the silicon block is ≤3%, and the particle size D2 of the second particles satisfies: D2<10 mm.

[0028] The third embodiment of the present application provides a silicon block obtained by a silicon powder molding method or the application of the above-mentioned silicon block in the production of Czochralski single crystals. Beneficial effects

[0029] The present application provides a silicon powder molding method according to the embodiments of the present application, which has at least the following technical effects:

[0030] (1) The present application uses pressure control to make the formed silicon blocks easy to remove from the mold without crushing and dusting. The silicon blocks obtained in the present application are easy to crush during filling, the particle size distribution after crushing is easy to control, and the amount of dust generated during the crushing process is low;

[0031] (2) The silicon blocks obtained in this application can be directly used for the production of Czochralski single crystals, and the charging density is increased to 0.18 g / cm 3 ~0.25g / cm 3 . BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0033] FIG1 is a perspective diagram of the exploded structure of a mold according to an embodiment of the present application;

[0034] FIG2 is a schematic diagram of the exploded structure of the mold according to an embodiment of the present application;

[0035] FIG3 is a front view of a mold according to an embodiment of the present application;

[0036] FIG4 is a cross-sectional view taken along line BB in FIG3 .

[0037] The marks in the figure are respectively represented as: 1-mold, 100-cylinder, 110-first surface, 120-second surface, 130-third surface, 200-cover, 201-step, 300-protective cover. Modes for Carrying Out the Invention

[0038] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0039] In the process of preparing the crystal rod, silicon powder cannot be directly fed into the material, and the silicon powder needs to be converted into silicon rods or silicon blocks. In order to improve the filling rate, the present application provides a silicon powder molding method, comprising the following steps: placing a mold 1 filled with silicon powder under a first pressure P1 condition, maintaining the first pressure time T1, and satisfying: 50MPa≤P1≤600MPa, 7min≤T1≤15min, to obtain a silicon block. For example, the value of the first pressure P1 (MPa) can be any value among 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, or a range consisting of any two values. For example, the value of the first pressure time T1 (min) can be any value among 7, 8, 9, 10, 11, 12, 13, 14, 15, or a range consisting of any two values. When the pressurization pressure is too low, it will affect the compaction density and waste working time. When the pressurization pressure is too high, although it will not affect the compaction density of the product, it will affect the life of the equipment and make it difficult to break the silicon block after molding.

[0040] In some embodiments, the first pressure P1 condition is achieved by increasing the pressure, and the increasing pressure step includes increasing the pressure to the first pressure P1 at a first pressure increasing rate v1, satisfying 20 MPa / s ≤ v1 ≤ 30 MPa / s. For example, the first pressure increasing rate v1 (MPa / s) can be any value selected from 20, 25, and 30, or a range consisting of any two values.

[0041] In some embodiments, before the mold 1 filled with silicon powder is placed under the first pressure P1 condition, the mold 1 filled with silicon powder is placed in a closed environment.

[0042] The present application places a mold 1 filled with silicon powder in a closed environment. In some embodiments, the mold 1 is sealed by a cover provided on the periphery of the mold 1, and the sealed mold 1 is pressurized. The present application overcomes the problem that wet pressing requires manual bagging and unloading operations each time, resulting in low production efficiency. In addition, wet pressing uses liquid transfer to pressurize the blank. During the pressing process, if the mold 1 is broken, the liquid can easily invade the pressed product, causing product contamination and affecting quality. The present application reduces the risk of silicon powder contamination by further providing a closed space on the periphery of the mold 1.

[0043] In some embodiments, the first pressure P1 condition is applied by a pressurized medium, the pressurized medium being a fluid, the mold 1 filled with silicon powder being placed before the first pressure P1 condition, and the mold 1 filled with silicon powder being placed in the cavity;

[0044] The mold 1 and the pressurized medium are separated by a cavity; alternatively, the pressurized medium is filled in the cavity and the mold 1 is in contact with the pressurized medium.

[0045] In some embodiments, the mold 1 and the pressurized medium are separated by a cavity, and the pressurized medium is liquid.

[0046] In some embodiments, a pressurized medium is filled in the cavity, the mold 1 is in contact with the pressurized medium, and the pressurized medium is gas.

[0047] In some embodiments, when the mold and the pressurized medium are separated by a cavity, the cavity maintains a dry environment with a temperature range of 20° C. to 25° C. and a humidity range of 40% to 50% rh. For example, the temperature of the dry environment is any value among 20° C., 21° C., 22° C., 23° C., 24° C., and 25° C., or a range consisting of any two values. For example, the humidity (% rh) is any value among 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, and 50, or a range consisting of any two values.

[0048] In some embodiments, the particle size of the silicon powder ranges from 0.1 μm to 1000 μm. For example, the particle size (μm) of the silicon powder can be any value selected from 0.1, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, or a range consisting of any two values.

[0049] In some embodiments, the mold 1 includes a first surface 110 and a second surface 120 disposed opposite to each other. The first surface 110 and the second surface 120 are connected by a third surface 130 . The first surface 110 and the third surface 130 receive a first pressure P1 .

[0050] In some embodiments, the pressure deviation PD of the first pressure P1 satisfies: -5 MPa≤PD≤5 MPa, such as the value of PD (MPa) can be any value of -5, -3, -2, 0, 1, 3, 5, or a range consisting of any two values.

[0051] In some embodiments, the mold containing silicon powder is subjected to a second pressure P2 for a second pressure time T2, satisfying 50 MPa ≤ P2 ≤ 200 MPa and 3 min ≤ T2 ≤ 7 min. For example, the second pressure P2 (MPa) can be any value selected from 50, 100, 150, and 200, or a range consisting of any two values. For example, the second pressure time T2 (min) can be any value selected from 3, 4, 5, 6, and 7, or a range consisting of any two values.

[0052] In some embodiments, the mold containing silicon powder is subjected to a third pressure P3 for a third pressure time T3, satisfying the conditions of 200 MPa ≤ P3 ≤ 600 MPa and 4 min ≤ T3 ≤ 8 min. For example, the third pressure P3 (MPa) can be any value selected from 200, 250, 300, 350, 400, 450, 500, 550, or 600, or a range consisting of any two values, and the third pressure time T3 (min) can be any value selected from 4, 5, 6, 7, or 8, or a range consisting of any two values.

[0053] In some embodiments, the mold 1 containing silicon powder is placed under a fourth pressure P4 for a fourth pressure time T4, satisfying 100 MPa ≤ P4 ≤ 600 MPa and 3 min ≤ T4 ≤ 6 min. For example, the fourth pressure P4 (MPa) can be any value selected from 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, and 600, or a range consisting of any two values, and the fourth pressure time T4 (min) can be any value selected from 3, 4, 5, and 6, or a range consisting of any two values.

[0054] In some embodiments, after the pressurization process is completed, the mold 1 is subjected to a first pressure relief process, which includes reducing the pressure to a fifth pressure P5 for T n Time, meeting: 10MPa≤P5≤100MPa, 1min≤T n≤2min. For example, the fifth pressure P5 (MPa) is any value among 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or a range consisting of any two values. n The value of (min) can be any value among 1, 1.5, 2 or a range consisting of any two values. In the present application, the fifth pressure P5 is maintained after the pressurization is completed, so as to further reduce the amount of dust generated when the formed silicon block is crushed.

[0055] In some embodiments, the pressure relief rate v2 satisfies 20 MPa / s≤v2≤30 MPa / s. For example, the pressure relief rate v2 (MPa / s) can be any value among 20, 25, 30, or a range consisting of any two values.

[0056] In some embodiments, the present application controls the pressure range of the pressurization of the present application by selecting a first pressure increase rate or a pressure relief rate.

[0057] In some embodiments, the pressurization time of the present application does not include the time of the pressure increasing process or the pressure releasing process.

[0058] As shown in FIG1 to FIG4, in some embodiments, the mold 1 is made of polyurethane material, and the density ρ0 of the polyurethane material satisfies: 1.00 g / cm 3 ≤ρ0≤1.01g / cm 3 .

[0059] In some embodiments, the mold 1 includes a cover 200 and a cylinder 100 , the cover 200 covers the cylinder 100 , and silicon powder is filled in the cylinder 100 .

[0060] In some embodiments, the inner diameter of the barrel 100 is 137 mm to 141 mm.

[0061] In some embodiments, the outer diameter of the barrel 100 is 154 mm to 160 mm.

[0062] In some embodiments, the height of the cylinder 100 is 691 mm to 697 mm.

[0063] In some embodiments, a protective cover 300 is provided on the outer periphery of the cover 200 , and the protective cover 300 covers at least a portion of the cover 200 .

[0064] In some embodiments, the protective cover 300 is disposed on the outer periphery of the cover body 200 to compact the cover body 200 .

[0065] In some embodiments, the pressurization method used in this application is isostatic pressing. During operation, the cover 200 of the mold 1 is opened, the material is loaded, and then the cover 200 is closed and pressurized to form the material. When discharging the material, the cover 200 of the mold 1 is opened, and pressure is applied to the bottom of the cylinder 100 to eject the silicon block formed in the mold 1. This has a short operation cycle and is suitable for batch production.

[0066] In some embodiments, the edge of the cover 200 includes a step 201 . The step 201 surrounds the cover 200 . The step 201 further enhances the sealing performance of the cover 200 and prevents silicon powder from leaking out.

[0067] In some embodiments, the wear rate G of the mold 1 satisfies: G<G0, where G0 is the material loss in g / cm 2 ; G0 satisfies: 0<G0≤0.1g / cm 2 .

[0068] In some embodiments, G0 is the material loss measured by the abrasion tester under specified conditions, and the unit of material loss is g / cm 2 .

[0069] The present application further provides a silicon block prepared by the above method.

[0070] In some embodiments, the silicon block is crushed to form first particles. Based on the mass of the silicon block, the first particles account for ≥97% of the mass of the silicon block, and the particle size D1 of the first particles satisfies: 10 mm ≤ D1.

[0071] In some embodiments, the particle size D1 of the first particles satisfies the following: 10 mm ≤ D1 ≤ 150 mm. For example, the particle size of the first particles is any value selected from 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, and 150, or a range consisting of any two values. In other embodiments, the particle size D1 (mm) of the first particles satisfies the following: 10 mm ≤ D1 ≤ 70 mm.

[0072] In some embodiments, the silicon block is crushed to form second particles, and the second particles account for ≤3% of the mass of the silicon block, based on the mass of the silicon block, and the particle size D2 of the second particles satisfies: D2 < 10 mm. For example, if the particle size of the second particles is 3 mm ≤ D2 < 10 mm, the percentage is 2-3%, and if the particle size of the second particles is 0 mm ≤ D2 < 3 mm, the percentage is ≤ 1%. The silicon blocks formed in this application have a reasonable particle size distribution after crushing, and a reasonable particle distribution is formed during the feeding process of the Czochralski single crystal production, facilitating the feeding operation.

[0073] The crushing method in the present application can be artificial crushing or mechanical vibration crushing. In some embodiments, artificial crushing is adopted.

[0074] This application adopts dry pressing technology to avoid contamination of raw materials, and can be produced quickly on a large scale, thereby improving production efficiency and realizing the application of the prepared silicon blocks in the production of Czochralski single crystals.

[0075] Example 1: Load raw polysilicon powder into a mold 1, as shown in Figures 1 to 4. The mold 1 of the present application is made of polyurethane material. After loading, use a scraper to scrape or flatten the silicon powder at the loading port, cover it with a cover 200 and a protective cover 300 to seal it. After sealing, an outer layer of a diaphragm is wrapped around the mold to form an isolation cavity to isolate the mold 1 from the pressurized environment. The mold 1 filled with raw polysilicon powder is placed in the equipment, and liquid is injected to a set height. The equipment starts to run. During the process, the pressure is set as follows: increase the pressure to 100MPa at a rate of 20MPa / s, and the pressurization time is 15min. After the pressurization is completed, the pressure is released at 30Mpa / s. After returning to normal pressure, the furnace is opened to extract the liquid and the mold 1 is taken out. During the pressurization process, the liquid evenly transmits the pressure to each side of the mold 1, and the pressure deviation between any two sides of the mold 1 is within the range of ±5MPa. Use pure water to rinse the surface of the mold 1, wipe off the residual pure water on the surface of the mold 1 after rinsing, and then unseal and demould; seal and package.

[0076] Examples 2 to 4: The pressurization method is the same as that of Example 1, except that the pressure value and pressurization time are adjusted. The specific parameters are shown in Table 1.

[0077] Comparative Example 1: The pressurization method is the same as that of Example 1, except that the pressure value and pressurization time are adjusted. The specific parameters are shown in Table 1.

[0078] Comparative Example 2: The silicon powder was not pressurized.

[0079] Calculation method:

[0080] Charging ratio = (B + C) / A * 100%, where A is the theoretical crucible charging capacity, in kg, B is the mass of the silicon powder blocks after pressing and crushing, in kg, and C is the mass of other materials such as doping elements, in kg.

[0081] Table 1 Preparation parameters and results of Examples 1 to 4 and Comparative Examples 1 to 2

[0082] The data from Examples 1-4 and Comparative Examples 1-2 show that the present method increases the charge ratio from 6% to 100% in the silicon powder state. The data from Example 4 show that when the pressurization pressure is too low, although the charge ratio is improved, the compaction density of the silicon blocks is affected and labor is increased. The data from Comparative Example 1 shows that increasing the pressurization pressure does not affect the compaction density of the product, but excessive pressurization pressure can shorten the equipment life and make it difficult to break the silicon blocks after molding.

[0083] Example 5: The preparation method is the same as that of Example 1, except that the pressurization pressure and pressurization time are adjusted. The pressure is increased to 50 MPa at a pressurization rate of 20 MPa / s, and the pressurization time is 3 min. After the pressurization is completed, the pressure is increased to 300 MPa at a pressurization rate of 20 MPa / s, and the pressurization time is 6 min. Specific parameters are shown in Table 2.

[0084] Examples 6 to 15: The preparation method is the same as that of Example 5, except that the pressurization pressure and pressurization time are adjusted. The specific parameters are shown in Table 2.

[0085] Table 2 Preparation parameters and results of Examples 5 to 15

[0086] As can be seen from the results in Table 2, the present invention improves the compaction density by controlling the pressure range and pressure time. The resulting molded silicon blocks generate less dust during the crushing process than the molded silicon blocks of Examples 1 to 4.

[0087] Example 16: The preparation method is the same as that of Example 1, except that the pressure and time are adjusted. The pressure is increased to 50 MPa at a pressure increase rate of 20 MPa / s, and the pressurization time is 3 min. After the pressurization is completed, the pressure is increased to 300 MPa at a pressure increase rate of 20 MPa / s, and the pressurization time is 6 min. The pressure is then maintained at 300 MPa and the pressurization is continued for 4 min. Specific parameters are shown in Table 3.

[0088] Examples 17 to 31: The preparation method is the same as that of Example 16, except that the pressurization pressure and pressurization time are adjusted. The specific parameters are shown in Table 3.

[0089] Table 3 Preparation parameters and results of Examples 16 to 31

[0090] From the results in Table 3, it can be seen that the present application improves the compaction density of silicon powder by controlling the pressure range and pressure time of pressurization, and the amount of dust generated in the crushing process of the obtained molded silicon blocks is lower than that of the molded silicon blocks in Examples 5 to 15.

[0091] Example 32: The preparation method is the same as that of Example 1, except that the pressurization pressure and pressurization time are adjusted. The pressure is increased to 50 MPa at a pressure increase rate of 20 MPa / s, and the pressurization time is 3 minutes. After the pressurization is completed, the pressure is increased to 300 MPa at a pressure increase rate of 20 MPa / s, and the pressurization time is 6 minutes. Then, the pressure is maintained at 300 MPa and the pressurization is continued for 6 minutes. Then, the pressure is reduced to 50 MPa at a pressure relief rate of 20 MPa / s, and the pressurization time is 1.5 minutes. Specific parameters are shown in Table 4.

[0092] Examples 33 to 50: The preparation method is the same as that of Example 32, except that the pressurization pressure and pressurization time are adjusted. The specific parameters are shown in Table 4.

[0093] Table 4 Preparation parameters and results of Examples 32 to 50

[0094] The results in Table 4 show that applying pressure during the silicon powder molding process can increase the compaction density of the silicon powder. The crushing results of the silicon blocks after molding show that the pressure relief step has little effect on the compaction density, but the dust content during the crushing process is significantly reduced compared to silicon powder molded without the pressure relief step.

[0095] The present invention improves compaction density by controlling the pressure range and pressure time. In addition, the particle size distribution range of the silicon blocks prepared in the present invention can be directly used for feeding after crushing, and there is no dust pollution during the crushing process.

[0096] The above is a detailed introduction to a silicon powder molding method, silicon blocks and applications provided by the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, based on the ideas of the present application, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for forming silicon powder, wherein: include: The mold (1) filled with silicon powder is placed under a first pressure P1 for a first pressure time T1, satisfying the following conditions: 50MPa≤P1≤600MPa, 7min≤T1≤15min, to obtain a silicon block.

2. The silicon powder molding method according to claim 1, wherein: The first pressure P1 condition is achieved by increasing the pressure, and the increasing pressure step includes increasing the pressure to the first pressure P1 at a first increasing pressure rate v1, satisfying 20MPa / s≤v1≤30MPa / s; and / or, before the mold (1) filled with silicon powder is placed in the first pressure P1 condition, the mold (1) filled with silicon powder is placed in a closed environment.

3. The silicon powder molding method according to claim 1, wherein: Applying the first pressure P1 through a pressurized medium, wherein the pressurized medium is a fluid, the mold (1) filled with silicon powder is placed before the first pressure P1 condition, and the mold (1) filled with silicon powder is placed in a cavity; The mold (1) and the pressurized medium are separated by the cavity; or, the pressurized medium is filled in the cavity, and the mold (1) is in contact with the pressurized medium.

4. The silicon powder molding method according to claim 3, wherein: When the mold (1) and the pressurized medium are separated by the cavity, the pressurized medium is liquid; when the pressurized medium is filled in the cavity, the mold (1) is in contact with the pressurized medium, and the pressurized medium is gas; and / or, When the mold (1) and the pressurized medium are separated by the cavity, the interior of the cavity maintains a dry environment, the temperature range of the dry environment is 20-25° C., and the humidity range is 40-50% rh.

5. The silicon powder molding method according to claim 1, wherein: The particle size of the silicon powder is 0.1 μm to 1000 μm.

6. The silicon powder molding method according to claim 1, wherein: The mold (1) comprises a first surface (110) and a second surface (120) arranged opposite to each other, the first surface (110) and the second surface (120) are connected via a third surface (130), and the first surface (110) and the third surface (130) receive the first pressure P1; and / or, The first surface (110), the second surface (120) and the third surface (130) receive the first pressure P1, and the pressure deviation PD applied by the first pressure P1 on the first surface (110), the second surface (120) and the third surface (130) satisfies: -5MPa≤PD≤5MPa.

7. The silicon powder molding method according to claim 1, wherein: The mold (1) comprises a cover (200) and a cylinder (100), the cover (200) covers the cylinder (100), and the silicon powder is filled in the cylinder (100); and / or, A protective sleeve (300) is provided on the outer periphery of the cover body (200), and the protective sleeve (300) is covered on at least a portion of the cover body (200); and / or, The edge of the cover body (200) comprises a step (201), and the step (201) surrounds the cover body (200).

8. The silicon powder molding method according to claim 1, wherein: The mold (1) is made of a polyurethane material, and the density ρ0 of the polyurethane material satisfies: 1.00 g / cm 3 ≤ρ0≤1.01g / cm 3 .

9. The silicon powder molding method according to claim 1, wherein: The wear rate G of the mold (1) satisfies: G<G0, wherein G0 is the material loss, in units of g / cm 2 ; The G0 satisfies: 0<G0≤0.1g / cm 2 .

10. The silicon powder molding method according to claim 1, wherein: Also includes, The mold (1) containing silicon powder is placed under a second pressure P2 for a second pressure time T2, satisfying 50 MPa≤P2≤200 MPa, 3 min≤T2≤7 min; The mold (1) filled with silicon powder is placed under a third pressure P3 for a third pressure time T3, satisfying 200MPa≤P3≤600MPa, 4min≤T3≤8min.

11. The silicon powder molding method according to claim 10, wherein: Also includes, The mold (1) filled with silicon powder is placed under a fourth pressure P4 for a fourth pressure time T4, satisfying 100MPa≤P4≤600MPa, 3min≤T4≤6min.

12. The silicon powder molding method according to any one of claims 1 to 11, wherein: The process further comprises: after the pressurization process is completed, applying a first pressure relief process to the mold (1), wherein the first pressure relief process comprises: reducing the pressure to a fifth pressure P5 for a period of T n Time, meet: 10MPa≤P5≤100MPa, 1min≤T n ≤2min.

13. A silicon block, wherein: include: The silicon block is prepared by the silicon powder molding method according to any one of claims 1 to 12.

14. The silicon block according to claim 13, wherein: The silicon block is crushed to form first particles, the first particles account for ≥97% of the mass of the silicon block, and the particle size D1 of the first particles satisfies: 10 mm ≤ D1; and / or, The silicon block is crushed to form second particles. Based on the mass of the silicon block, the mass percentage of the second particles in the silicon block is ≤3%, and the particle size D2 of the second particles satisfies: D2<10 mm.

15. Use of a silicon block obtained by the silicon powder molding method according to any one of claims 1 to 12 in the production of Czochralski single crystals; or use of a silicon block according to claim 13 or 14 in the production of Czochralski single crystals.

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