Inner-layer quartz sand for long-service-life single-crystal crucible and preparation method and application of inner-layer quartz sand

Abstract

The invention discloses inner-layer quartz sand for a long-service-life single-crystal crucible and a preparation method and application of the inner-layer quartz sand, and one or two of 1-15 ppm of bismuth oxide and antimony trioxide are uniformly doped into the quartz sand through a high-temperature acid doping process. As the antimony oxide and the bismuth oxide are doped in the quartz sand, the viscosity of quartz melt can be reduced, overflow of a large amount of gas generated in the quartz sand melting process is facilitated, and the content of microbubbles in the inner layer of the quartz crucible is reduced, so that the density and the temperature resistance of the inner layer of the quartz crucible are improved, the defects caused by bubbles are reduced, and the service life of the crucible is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of high-purity quartz materials, and particularly relates to inner-layer quartz sand for a long-life single crystal crucible and a preparation method and application thereof. Background Art

[0002] Quartz crucible is the carrier for pulling photovoltaic and semiconductor single crystals. Its impurity content has an important impact on the quality of single crystals, and its service life affects the production cost of crystals. Since the downstream industry has strict standards for the purity, cleanliness and precision of quartz crucibles, and the evolution of large silicon wafers also puts higher requirements on crucible products, the quartz crucible process technology has been developing in the direction of "high purity, large size, low cost and long life", and the inner layer of the quartz crucible has more stringent requirements on high-purity quartz sand.

[0003] Therefore, under the premise of ensuring that the impurities in the quartz crucible are controllable, maximizing the service life of the quartz crucible is an important measure to reduce costs in the photovoltaic and semiconductor industries.

[0004] An important reason that affects the service life of quartz crucibles and causes the destruction of quartz crucibles is that the microbubbles in the inner glass layer of the quartz crucible continue to grow and damage in a high temperature environment, causing damage to the opening. The high-temperature silicon liquid invades the inside of the opening and continues to cause damage, and the corroded quartz crucible will also enter the silicon liquid, thereby polluting and affecting the quality of the silicon crystal.

[0005] To improve the service life of quartz crucibles, on the one hand, we need to purify the quartz sand used in the manufacture of quartz crucibles, especially reduce the inclusions and hydroxyl groups, so as to reduce the large number of microbubbles generated by these impurities during the high-temperature melting of quartz sand in the manufacturing process of crucibles; on the other hand, we need to improve the crucible preparation process. Through vacuuming and other processes, we can remove a large number of microbubbles generated during the melting process of quartz sand.

[0006] The above process methods have limited effect on the removal of microbubbles, and high-purity quartz sand is required to achieve a certain effect. The preparation of quartz is very difficult, which also causes the cost of quartz crucibles to increase. Summary of the invention

[0007] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for preparing inner quartz sand for long-life single crystal crucible in view of the shortcomings of the prior art, so as to achieve a dense inner layer of the quartz crucible and significantly reduce bubbles, thereby improving the temperature resistance and service life of the quartz crucible.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows: The invention discloses an inner layer quartz sand for a long-life single crystal crucible, wherein the SiO2 content in the quartz sand is ≥99.99%, the impurity content is ≤33.5ppm, the impurities contain at least one of bismuth oxide and antimony trioxide, and the total content of bismuth oxide and / or antimony trioxide is 1ppm-15ppm.

[0009] Preferably, the impurities contain bismuth oxide and antimony trioxide, and the total content of the two is 5 ppm-14 ppm.

[0010] Furthermore, the present invention also provides a method for preparing an inner layer of quartz sand for a long-life single crystal crucible, comprising the following steps: (1) The quartz sand raw material is subjected to high-temperature roasting, water quenching, crushing, pickling, magnetic separation, high-temperature chlorination, and pickling to obtain high-purity quartz sand particles; (2) dissolving bismuth oxide and / or antimony trioxide in hydrochloric acid to obtain an acid solution; (3) The acid solution obtained in step (2) is evenly sprayed onto the surface of the high-purity quartz sand particles in step (1), and then dried.

[0011] Preferably, in step (1), the high temperature calcination temperature is 1200-1500° C. and the time is 30-60 min.

[0012] Preferably, in step (1), after crushing, the particle size of the quartz sand particles is 50-1000 μm; the crushed and high-temperature chlorinated quartz sand particles are pickled using hydrofluoric acid or a mixture of hydrofluoric acid and hydrochloric acid, and the pickling temperature is 50-100°C.

[0013] Preferably, in step (1), the temperature of the high temperature chlorination process is 1200-1500°C, one or a mixture of two gases of Cl2 and HCl is used, and the chlorination time is 30-120 min.

[0014] The present invention reduces the impurity content of Al, Fe, Mg, Ca, K, Na, Li and the like in quartz sand to below 15 ppm through the above process.

[0015] Preferably, in step (2), the mass concentration of bismuth oxide and / or antimony trioxide in the acid solution is 0.05-0.10%.

[0016] Preferably, in step (2), the mass ratio of bismuth oxide to antimony trioxide in the acid solution is 1:1-2.

[0017] Preferably, in step (3), the ratio of the acid solution to the high-purity quartz sand particles is 1:50-100, and the drying temperature is not less than 200°C.

[0018] Furthermore, the present invention also claims to protect the use of the above-mentioned quartz sand as an inner layer material for preparing a single crystal crucible. Beneficial Effects

[0019] The present invention uniformly adds 1ppm-15ppm of one or two of bismuth oxide and antimony trioxide into quartz sand through a high-temperature acid doping process. Among them, the addition of bismuth oxide can improve the compressive strength of quartz glass. This is because bismuth oxide can promote the crystallization of quartz glass, reduce the size of microcrystals in quartz glass, and make the structure more compact, thereby improving strength and hardness. The addition of bismuth oxide can also improve the wear resistance of quartz glass. When manufacturing quartz glass, bismuth oxide can improve the chemical stability of quartz glass, thereby extending the service life. The addition of bismuth oxide can also improve the optical properties of quartz glass. Bismuth oxide can improve the refractive index and transparency of quartz glass, so that it has better optical quality and light transmittance. Replacing other metal oxides, such as boron dioxide, antimony oxide, etc., with bismuth oxide can also effectively improve the ultraviolet transmittance of quartz glass.

[0020] Under high temperature conditions, antimony trioxide in quartz sand will be reduced to antimony dioxide, while oxidizing some of the impurity elements in the quartz glass. Antimony dioxide is then oxidized to antimony trioxide, forming a redox cycle. This cycle allows the impurities in the quartz glass to be continuously oxidized and removed, thereby improving the clarity of the quartz glass. Antimony trioxide also has the effect of inhibiting the formation of bubbles. During the quartz glass manufacturing process, there may be some oxides or other impurities in the quartz glass raw materials at high temperatures. These impurities will form bubbles and affect the transparency of the quartz glass. Antimony trioxide can reduce these oxides or impurities, prevent bubble formation, and thus improve the quality of the glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0022] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0023] The present invention can be better understood with reference to the following examples.

[0024] In the following examples, the quartz sand raw material is subjected to high-temperature roasting, water quenching, crushing, pickling, magnetic separation, high-temperature chlorination, and pickling to obtain high-purity quartz sand particles. The composition of the purified quartz sand is as follows: SiO2 content 99.998%, impurity content 14.7ppm (including Fe=0.052ppm, Mg=0.081ppm, Ca=0.332ppm, Al=12.944ppm, Na=0.437ppm, K=0.720ppm).

[0025] Bismuth oxide was purchased from Hunan Zhongcai Shengte with a purity of 99.99%.

[0026] Antimony trioxide was purchased from Shanxing Antimony Industry with a purity of 99.8%. Example 1

[0027] Combination Figure 1 The process flow is as follows: bismuth oxide and antimony trioxide are dissolved in hydrochloric acid in a mass ratio of 1:2 to form a solution with a concentration of 0.05%, and the solution is sprayed at a ratio of 1:100 on the above-mentioned high-purity quartz sand that has been purified by high-temperature roasting, water quenching, crushing, pickling, magnetic separation, high-temperature chlorination, pickling, etc., and then dried at 250°C to obtain the doped long-life single crystal crucible inner layer sand. The chemical composition of the sand is as follows: SiO2 content 99.997%, impurity content 21.4ppm (including Fe=0.054ppm, Mg=0.083ppm, Ca=0.341ppm, Al=12.950ppm, Na=0.438ppm, K=0.722ppm, Bi2O3=1.709ppm, Sb2O3=3.335ppm). Example 2

[0028] Bismuth oxide and antimony trioxide were dissolved in hydrochloric acid in a mass ratio of 1:1 to prepare a solution with a concentration of 0.07%, and the solution was sprayed at a ratio of 1:50 on the above-mentioned high-purity quartz sand that had been purified by high-temperature roasting, water quenching, crushing, pickling, magnetic separation, high-temperature chlorination, pickling, etc., and then dried at 250°C to obtain doped long-life single crystal crucible inner layer sand. The chemical composition of the sand is as follows: SiO2 content 99.997%, impurity content 30.59ppm (including Fe=0.057ppm, Mg=0.088ppm, Ca=0.342ppm, Al=13.045ppm, Na=0.438ppm, K=0.735ppm, Bi2O3=7.318ppm, Sb2O3=7.422ppm). Example 3

[0029] Bismuth oxide was dissolved in hydrochloric acid to prepare a solution with a concentration of 0.05%, and the solution was sprayed at a ratio of 1:50 on the high-purity quartz sand that had been purified by high-temperature roasting, water quenching, crushing, pickling, magnetic separation, high-temperature chlorination, pickling, etc., and then dried at 300°C to obtain doped long-life single crystal crucible inner layer sand. The chemical composition of the sand was as follows: SiO2 content 99.996%, impurity content 26.84ppm (including Fe=0.055ppm, Mg=0.085ppm, Ca=0.346ppm, Al=12.983ppm, Na=0.427ppm, K=0.733ppm, Bi2O3=10.269ppm). Example 4

[0030] Antimony trioxide was dissolved in hydrochloric acid to prepare a solution with a concentration of 0.05%, and the solution was sprayed at a ratio of 1:50 on the high-purity quartz sand that had been purified by high-temperature roasting, water quenching, crushing, pickling, magnetic separation, high-temperature chlorination, pickling, etc., and then dried at 250°C to obtain doped long-life single crystal crucible inner layer sand. The chemical composition of the sand was as follows: SiO2 content 99.996%, impurity content 33.42ppm (including Fe=0.365ppm, Mg=0.098ppm, Ca=0.375ppm, Al=14.037ppm, Na=0.482ppm, K=0.831ppm, Sb2O3=9.753ppm). Example 5

[0031] The high-purity quartz sand used before doping and the quartz sand prepared in Example 1, Example 2, Example 3, and Example 4 were used as the inner layer material of the crucible to make a 28-inch single crystal crucible, and the quality of the crucible was tested. The relevant test results are shown in Table 1. Among them, the impurity points in the wall, the bubbles in the wall, and the heat resistance (deformation rate) were measured by JC / T 1048-2018 "Quartz Crucible for Single Crystal Silicon Growth".

[0032] Table 1

[0033] As can be seen from Table 1, after bismuth oxide and / or antimony trioxide are added to the quartz sand of the present invention, the impurity points in the inner layer of the crucible can be reduced to a certain extent, and the bubbles in the inner layer of the crucible can be significantly reduced. This is mainly due to the fact that after bismuth oxide and / or antimony trioxide are added, the viscosity of the quartz melt can be reduced, which is beneficial to the precipitation of some impurity elements, especially for the overflow of gas. The reduction of impurities and bubbles also greatly improves the heat resistance of the crucible, the deformation rate is reduced from 2.7% to 0.8%, and the life of the quartz crucible is significantly improved. In addition, the co-doping effect of bismuth oxide and antimony trioxide is also significantly better than the single doping effect, especially it can greatly reduce the number of large bubbles, thereby significantly improving the heat resistance. This is mainly because the synergistic effect of these two elements greatly reduces the melt viscosity while ensuring the high temperature performance of the quartz crucible, which is beneficial to the discharge of the gas generated during the melting process of the quartz sand.

[0034] The present invention provides an inner layer of quartz sand for a long-life single crystal crucible and a preparation method and application thereof. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A long-life single crystal crucible inner layer quartz sand, characterized in that: The SiO2 content in the quartz sand is ≥99.99%, the impurity content is ≤33.5ppm, the impurities contain at least one of bismuth oxide and antimony trioxide, and the total content of bismuth oxide and / or antimony trioxide is 1ppm-15ppm.

2. The inner layer quartz sand for long-life single crystal crucible according to claim 1, characterized in that: The impurities include bismuth oxide and antimony trioxide, and the total content of the two is 5 ppm-14 ppm.

3. The method for preparing the inner layer quartz sand for the long-life single crystal crucible according to claim 1, characterized in that: The steps include: (1) The quartz sand raw material is subjected to high-temperature roasting, water quenching, crushing, pickling, magnetic separation, high-temperature chlorination, and pickling to obtain high-purity quartz sand particles; (2) dissolving bismuth oxide and / or antimony trioxide in hydrochloric acid to obtain an acid solution; (3) The acid solution obtained in step (2) is evenly sprayed onto the surface of the high-purity quartz sand particles in step (1), and then dried.

4. The method for preparing inner layer quartz sand for long-life single crystal crucible according to claim 3, characterized in that: In step (1), the high temperature calcination temperature is 1200-1500°C and the time is 30-60 minutes.

5. The method for preparing inner layer quartz sand for long-life single crystal crucible according to claim 3, characterized in that: In step (1), after crushing, the particle size of the quartz sand particles is 50-1000 μm; the crushed and high-temperature chlorinated quartz sand particles are pickled using hydrofluoric acid or a mixture of hydrofluoric acid and hydrochloric acid, and the pickling temperature is 50-100°C.

6. The method for preparing inner layer quartz sand for long-life single crystal crucible according to claim 3, characterized in that: In step (1), the temperature of the high temperature chlorination process is 1200-1500°C, one or a mixture of two gases of Cl2 and HCl is used, and the chlorination time is 30-120 minutes.

7. The method for preparing inner layer quartz sand for long-life single crystal crucible according to claim 3, characterized in that: In step (2), the mass concentration of bismuth oxide and / or antimony trioxide in the acid solution is 0.05-0.10%.

8. The method for preparing inner layer quartz sand for long-life single crystal crucible according to claim 7, characterized in that: In step (2), the mass ratio of bismuth oxide to antimony trioxide in the acid solution is 1:1-2.

9. The method for preparing inner layer quartz sand for long-life single crystal crucible according to claim 3, characterized in that: In step (3), the ratio of the acid solution to the high-purity quartz sand particles is 1:50-100, and the drying temperature is not less than 200°C.

10. Use of the quartz sand according to claim 1 as an inner layer material for preparing a single crystal crucible.

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