A process for producing polysilicon raw materials and masterbatch for zone melting

Abstract

The present invention relates to the technical field of polysilicon production, and in particular to a process for producing a combined masterbatch of polysilicon raw materials for zone melting, comprising the following steps: installing a masterbatch silicon core on an inner ring electrode, installing a zone melting silicon core on a middle ring electrode and an outer ring electrode; connecting the masterbatch silicon core and the zone melting silicon core with phase current, and passing a mixture of hydrogen and trichlorosilane; when the silicon core masterbatch grows to a preset diameter, the inner ring electrode is powered on and disconnected; the zone melting silicon core continues to be powered on, and the zone melting polysilicon raw materials grow to a preset diameter, and the middle ring electrode and the outer ring electrode are powered off; disassembling the reduction furnace, and disassembling the silicon core masterbatch and the zone melting polysilicon raw materials. In the present invention, the silicon core masterbatch and the zone melting polysilicon raw materials are jointly produced, saving production costs; disconnecting the inner ring current makes the feed gas circulation more powerful and the raw material growth gas field more uniform; after the silicon core masterbatch stops growing, the reaction atmosphere temperature is reduced to avoid atomization, and the raw material growth temperature field is more uniform, thereby improving the quality of the zone melting polysilicon raw materials.

Description

Technical Field

[0001] The present invention relates to the technical field of polysilicon production, in particular to a production process of polysilicon raw material combined with masterbatch for zone melting. Background Art

[0002] Electronic-grade polysilicon is one of the most basic and main raw materials for manufacturing semiconductor silicon wafers. It can be divided into electronic-grade polysilicon for zone melting and electronic-grade polysilicon for direct pulling. The quality requirements for electronic-grade polysilicon for zone melting are more stringent.

[0003] Currently, polysilicon raw materials for zone melting are mostly produced using the modified Siemens method, which involves passing a mixture of chlorosilane and hydrogen into a CVD reduction furnace and utilizing chemical vapor deposition reactions to deposit and grow on pre-placed silicon cores.

[0004] The production process of polysilicon raw materials for zone melting is similar to that of silicon core masterbatch. The production of silicon core masterbatch is to use high-purity trichlorosilane gas and high-purity hydrogen mixed in a certain ratio to form a raw material mixed gas, which is introduced into a reduction reactor and continuously deposited on the heated high-purity silicon core, so that the diameter of the silicon core gradually becomes thicker to form polycrystalline silicon rods. Then, through a dedicated reduction process, that is, on the basis of producing polycrystalline silicon rods, the ratio of hydrogen to trichlorosilane gas is increased, and its growth temperature is controlled at 1060-1070 degrees to reduce the growth rate of the silicon rods so that the surface of the silicon rods is evenly and slowly deposited, thereby obtaining silicon core masterbatch that meets the requirements.

[0005] Polysilicon raw materials for zone melting and silicon core masterbatch can be jointly produced by taking advantage of multiple pairs of rods, but there is currently no polysilicon process system or device for the joint production of polysilicon raw materials for zone melting and silicon core masterbatch.

[0006] In order to solve the above problems, a process for producing polysilicon raw materials and combined masterbatch for zone melting was designed.

[0007] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0008] The present invention provides a zone-melting polysilicon combined production process and device, thereby effectively solving the problems in the background technology.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is: a process for producing polysilicon raw materials and masterbatch for zone melting, comprising the following steps:

[0010] The inner ring electrode is equipped with a number of masterbatch silicon cores, and the middle ring electrode and the outer ring electrode are equipped with a number of zone melting silicon cores;

[0011] The masterbatch silicon core and the zone melting silicon core are connected to the same current, and a mixed gas of hydrogen and trichlorosilane is passed into the reduction furnace;

[0012] When the silicon core masterbatch grows to the preset diameter, the DCS program starts, and the ratio of hydrogen and trichlorosilane mixed gas is reduced by remote control. At the same time, the current flowing through the masterbatch silicon core is reduced to the preset value within the specified time, and the inner ring electrode is energized and disconnected;

[0013] The melt zone silicon core continues to be energized, and the polysilicon raw material for the melt zone grows to a preset diameter. The DSC program is started, and the ratio of the hydrogen and trichlorosilane mixed gas is reduced by remote control. At the same time, the current flowing through the melt zone silicon core is reduced to a preset value within a specified time, and the middle ring electrode and the outer ring electrode are energized and disconnected;

[0014] Disassemble the reduction furnace, disassemble the grown silicon core masterbatch and polysilicon raw materials for zone melting.

[0015] Furthermore, the reduction in the ratio of the hydrogen and trichlorosilane mixed gas is achieved by changing the feed ratio of hydrogen and trichlorosilane gases.

[0016] Furthermore, the inner ring electrode, the middle ring electrode and the outer ring electrode are arranged in a ring shape from the inside to the outside.

[0017] Furthermore, the plurality of masterbatch silicon cores are combined into a plurality of U-shaped inner ring heating elements, and the plurality of zone melting silicon cores are combined into a plurality of U-shaped middle ring heating elements and a plurality of U-shaped outer ring heating elements.

[0018] Furthermore, the inner ring electrode, the middle ring electrode and the outer ring electrode are arranged on one side of the chassis, and the other side of the chassis is provided with an air inlet and an air outlet;

[0019] The chassis is fixedly connected to the furnace drum of the reduction furnace, and the furnace drum and the chassis are detachable.

[0020] Furthermore, the furnace drum is provided with a jacket layer, the jacket layer is passed through the furnace drum cooling water, and the outside of the furnace drum is provided with a water inlet pipe and a water outlet pipe.

[0021] Furthermore, a plurality of guide plates are provided inside the jacket layer.

[0022] Furthermore, a sight glass is provided on the outside of the furnace.

[0023] Furthermore, the bottom ends of the masterbatch silicon core and the melt zone silicon core are connected to the electrodes of the chassis through graphite seats.

[0024] The beneficial effects of the present invention are as follows: a plurality of masterbatch silicon cores are installed on the inner ring electrode, a plurality of zone melting silicon cores are installed on the middle ring electrode and the outer ring electrode, different phase currents are connected to the masterbatch silicon cores and the zone melting silicon cores, the current passes through the silicon cores to generate a thermoelectric effect, the hydrogen introduced into the reduction furnace and the trichlorosilane generate a chemical vapor deposition reaction under the heat generated by the electrothermal effect, the silicon core masterbatch and the polycrystalline silicon raw material for the zone melting gradually grow, the silicon core masterbatch grows to a preset diameter, the DCS program controls, reduces the ratio of the hydrogen and trichlorosilane mixed gas, disconnects the current of the inner ring electrode, and the polycrystalline silicon raw material for the zone melting continues to grow, and when it grows to the preset diameter, the DCS program controls, reduces the ratio of the hydrogen and trichlorosilane mixed gas, disconnects the current of the middle ring electrode and the outer ring electrode, and disassembles the grown silicon core masterbatch and the polycrystalline silicon raw material for the zone melting. The joint production of silicon core masterbatch and polysilicon raw materials for zone melting saves production space, improves resource utilization, and saves production costs; after the current of the inner ring electrode is disconnected, the circulation of the feed gas entering the reduction furnace becomes stronger and more powerful, and the gas field of the growth environment of the polysilicon raw materials for zone melting becomes more uniform; after the growth of the silicon core masterbatch in the inner ring stops, the temperature of the reaction atmosphere in the reduction furnace is also reduced, avoiding the atmosphere temperature from being too high and causing atomization, and the temperature field of the polysilicon raw materials for zone melting in the middle ring and outer ring is also more uniform, further improving the quality of the polysilicon raw materials for zone melting. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 Flow chart of the production process of polysilicon raw materials and masterbatch for zone melting

[0027] Figure 2 Schematic diagram of the structure of the combined masterbatch production device for polysilicon raw materials for zone melting

[0028] Figure 3 Schematic diagram of the chassis structure

[0029] Figure 4 Schematic diagram of the U-shaped inner ring heating element structure

[0030] Figure 5 Schematic diagram of the U-shaped central ring heating element structure

[0031] Figure numerals: 1. Reduction furnace; 11. Furnace drum; 111. Guide plate; 112. Sight glass; 113. Jacket layer; 114. Water inlet pipe; 115. Water outlet pipe; 12. Chassis; 121. Inner ring electrode; 122. Middle ring electrode; 123. Outer ring electrode; 124. Air inlet; 125. Exhaust port; 2. Masterbatch silicon core; 21. U-shaped inner ring heating element; 3. Zone melting silicon core; 31. U-shaped middle ring heating element; 32. U-shaped outer ring heating element; 4. Graphite seat. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0033] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by “center”, “up”, “down”, “left”, “right”, “vertical”, “horizontal”, “inside” and “outside” are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; they may refer to mechanical or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0035] like Figure 1 As shown, a process for producing polysilicon raw materials and masterbatch for zone melting includes the following steps:

[0036] The inner ring electrode 121 is installed with a number of masterbatch silicon cores 2, and the middle ring electrode 122 and the outer ring electrode 123 are installed with a number of zone melting silicon cores 3;

[0037] The masterbatch silicon core 2 and the melt zone silicon core 3 are connected to the same current, and a mixed gas of hydrogen and trichlorosilane is passed into the reduction furnace 1;

[0038] When the silicon core masterbatch grows to a preset diameter, the DCS program starts, and the ratio of the hydrogen and trichlorosilane mixed gas is reduced by remote control. At the same time, the current flowing through the masterbatch silicon core 2 is reduced to a preset value within a specified time, and the inner ring electrode 121 is energized and disconnected;

[0039] The melt zone silicon core 3 continues to be energized, and the polysilicon raw material for the melt zone grows to a preset diameter. The DSC program is started, and the ratio of the hydrogen and trichlorosilane mixed gas is reduced by remote control. At the same time, the current flowing through the melt zone silicon core 3 is reduced to a preset value within a specified time, and the middle ring electrode 122 and the outer ring electrode 123 are energized and disconnected.

[0040] Disassemble the reduction furnace 1, and disassemble the grown silicon core mother material and the polysilicon raw material for zone melting.

[0041] By installing a number of masterbatch silicon cores 2 on the inner ring electrode 121, and installing a number of zone melting silicon cores 3 on the middle ring electrode 122 and the outer ring electrode 123, different phase currents are connected to the masterbatch silicon cores 2 and the zone melting silicon cores 3. The current generates a thermoelectric effect through the silicon cores, and the hydrogen and trichlorosilane introduced into the reduction furnace 1 react with each other under the heat generated by the electrothermal effect to produce a chemical vapor deposition reaction. The silicon core masterbatch and the polycrystalline silicon raw material for the zone melting gradually grow. When the silicon core masterbatch grows to a preset diameter, the DCS program controls the ratio of the hydrogen and trichlorosilane mixed gas to be reduced, and the current of the inner ring electrode 121 is disconnected. The polycrystalline silicon raw material for the zone melting continues to grow. When the silicon core masterbatch grows to the preset diameter, the DCS program controls the ratio of the hydrogen and trichlorosilane mixed gas to be reduced, and the current of the middle ring electrode 122 and the outer ring electrode 123 is disconnected. The grown silicon core masterbatch and the polycrystalline silicon raw material for the zone melting are disassembled. The silicon core masterbatch and the polysilicon raw material for zone melting are jointly produced, which saves production space, improves resource utilization, and saves production costs; after the current of the inner ring electrode 121 is disconnected, the circulation flow of the feed gas entering the reduction furnace 1 is stronger and more powerful, and the gas field of the growth environment of the polysilicon raw material for zone melting is more uniform; after the silicon core masterbatch of the inner ring stops growing, the temperature of the reaction atmosphere in the reduction furnace 1 is also reduced, avoiding the atmosphere temperature from being too high and causing atomization, and the temperature field of the polysilicon raw material for zone melting in the middle ring and the outer ring is also more uniform, further improving the quality of the polysilicon raw material for zone melting.

[0042] In this embodiment, the ratio of the hydrogen and trichlorosilane mixed gas is reduced by changing the feed ratio of hydrogen and trichlorosilane gases.

[0043] By changing the feed ratio of hydrogen and trichlorosilane gas, the ratio of hydrogen and trichlorosilane mixed gas is reduced to meet the different quality requirements of silicon core masterbatch and polysilicon raw material for zone melting.

[0044] In this embodiment, the inner ring electrode 121 , the middle ring electrode 122 and the outer ring electrode 123 are arranged in a ring shape from the inside to the outside.

[0045] By arranging the inner ring electrode 121, the middle ring electrode 122 and the outer ring electrode 123 in a ring shape, the rate and efficiency of the electrochemical reaction are improved, the performance of the electrode is improved, the position and rate of the electrochemical reaction are better controlled, the selectivity of the electrode is improved, the contamination of the electrode surface is reduced, and the life and stability of the electrode are improved.

[0046] In this embodiment, a plurality of masterbatch silicon cores 2 are combined into a plurality of U-shaped inner ring heating elements 21 , and a plurality of zone melt silicon cores 3 are combined into a plurality of U-shaped middle ring heating elements 31 and a plurality of U-shaped outer ring heating elements 32 .

[0047] Several masterbatch silicon cores 2 are combined into several U-shaped inner ring heating elements 21, and several zone melting silicon cores 3 are combined into several U-shaped middle ring heating elements 31 and several U-shaped outer ring heating elements 32. The U-shaped heating elements can make the connected phase current circulate, making the silicon core heating more uniform and stable, and improving the quality of the silicon core masterbatch and the polysilicon raw material for zone melting.

[0048] like Figures 2 to 5 As shown, the inner ring electrode 121, the middle ring electrode 122 and the outer ring electrode 123 are arranged on one side of the chassis 12, and the other side of the chassis 12 is provided with an air inlet 124 and an air outlet 125;

[0049] The chassis 12 is fixedly connected to the furnace drum 11 of the reduction furnace 1 , and the furnace drum 11 and the chassis 12 are detachable.

[0050] The furnace drum 11 is fixedly connected to the bottom plate 12 and can be disassembled to facilitate the collection of silicon core mother materials grown later and polysilicon raw materials for zone melting.

[0051] In this embodiment, the furnace drum 11 is provided with a jacket layer 113 , through which cooling water flows, and a water inlet pipe 114 and a water outlet pipe 115 are provided on the outside of the furnace drum 11 .

[0052] The cooling water of the furnace drum 11 in the jacket layer 113 cools the reduction furnace 1, thereby extending the service life of the equipment.

[0053] In this embodiment, a plurality of guide plates 111 are provided inside the jacket layer 113 .

[0054] By arranging a plurality of guide plates 111 inside the jacket layer 113 , the cooling water of the traction furnace drum 11 is circulated, thereby improving the cooling effect of the furnace drum 11 .

[0055] In this embodiment, a sight glass 112 is provided on the outside of the furnace drum 11 .

[0056] The sight glass 112 provided outside the furnace drum 11 can observe in real time the growth state of the silicon core masterbatch and the polysilicon raw material for zone melting inside the reduction furnace 1, and ensure that the quality of the silicon core masterbatch and the polysilicon raw material for zone melting meets the required standards.

[0057] In this embodiment, the bottom ends of the masterbatch silicon core 2 and the melt zone silicon core 3 are connected to the electrodes of the bottom plate 12 through the graphite seat 4 .

[0058] The bottom ends of the masterbatch silicon core 2 and the zone melting silicon core 3 are connected to the electrodes of the bottom plate 12 through the graphite seat 4, so that the phase current flows to form a closed loop. The graphite seat 4 increases the conductivity between the silicon core and the electrode to ensure that the silicon core can continue to heat up.

[0059] The zone melting polysilicon raw material combined with masterbatch production process of the present invention is applicable to large-scale multi-circuit electronic-grade polysilicon reduction furnaces.

[0060] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for producing polysilicon raw materials and masterbatch for zone melting, characterized in that: The following steps are involved: The inner ring electrode is equipped with a number of masterbatch silicon cores, and the middle ring electrode and the outer ring electrode are equipped with a number of zone melting silicon cores; The masterbatch silicon core and the zone melting silicon core are connected to different phase currents, and a mixed gas of hydrogen and trichlorosilane is passed into the reduction furnace; When the silicon core masterbatch grows to the preset diameter, the DCS program starts, and the ratio of hydrogen and trichlorosilane mixed gas is reduced by remote control. At the same time, the current flowing through the masterbatch silicon core is reduced to the preset value within the specified time, and the inner ring electrode is energized and disconnected; The melt zone silicon core continues to be energized, and the polysilicon raw material for the melt zone grows to a preset diameter. The DSC program is started, and the ratio of the hydrogen and trichlorosilane mixed gas is reduced by remote control. At the same time, the current flowing through the melt zone silicon core is reduced to a preset value within a specified time, and the middle ring electrode and the outer ring electrode are energized and disconnected; Disassemble the reduction furnace, disassemble the grown silicon core masterbatch and polysilicon raw materials for zone melting.

2. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 1, characterized in that: The reduction in the ratio of the hydrogen and trichlorosilane mixed gas is achieved by changing the feed ratio of hydrogen and trichlorosilane gases.

3. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 1, characterized in that: The inner ring electrode, the middle ring electrode and the outer ring electrode are arranged in a ring shape from the inside to the outside.

4. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 1, characterized in that: The plurality of masterbatch silicon cores are combined into a plurality of U-shaped inner ring heating elements, and the plurality of zone melting silicon cores are combined into a plurality of U-shaped middle ring heating elements and a plurality of U-shaped outer ring heating elements.

5. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 1, characterized in that: The inner ring electrode, the middle ring electrode and the outer ring electrode are arranged on one side of the chassis, and the other side of the chassis is provided with an air inlet and an air outlet; The chassis is fixedly connected to the furnace drum of the reduction furnace, and the furnace drum and the chassis are detachable.

6. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 5, characterized in that: The furnace drum is provided with a jacket layer, and furnace drum cooling water is passed through the jacket layer. A water inlet pipe and a water outlet pipe are provided on the outside of the furnace drum.

7. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 6, characterized in that: A plurality of guide plates are arranged inside the jacket layer.

8. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 5, characterized in that: A sight glass is provided on the outside of the furnace.

9. The process for producing polysilicon raw materials and masterbatch for zone melting according to claim 5, characterized in that: The bottom ends of the masterbatch silicon core and the zone melting silicon core are connected to the electrodes of the chassis through graphite seats.

Images