Electronic grade polycrystalline silicon rod crushing method and system

Abstract

The invention relates to the technical field of polycrystalline silicon, in particular to an electronic-grade polycrystalline silicon rod crushing method and system, and the method comprises the following steps: 1, carrying out heating-quenching on a polycrystalline silicon rod to generate cracks on the surface and in the polycrystalline silicon rod; 2, putting the polycrystalline silicon rod into a closed container, vacuumizing the closed container, and injecting a proper amount of water to fill cracks and hidden cracks of the polycrystalline silicon rod with the water; 3, discharging the water in the closed container, quenching the polycrystalline silicon rod to enable the water in the cracks and hidden cracks to be condensed into ice, and crushing the polycrystalline silicon rod; and 4, recovering the polycrystalline silicon block to room temperature, and removing water in the polycrystalline silicon block. According to the invention, manpower can be saved, contact between the silicon material and people is reduced, and the silicon material is prevented from being polluted; mechanical crushing is not needed, so that introduction of metal impurities is reduced; and in addition, internal hidden cracks can be shown, repeated reworking caused by hidden crack showing in the follow-up cleaning procedure is avoided, and the crushing efficiency is improved.

Description

[0001] This application is a divisional application filed for an application with an application date of June 30, 2023, application number 202310803300.2, and invention name “A method and system for crushing electronic-grade polysilicon rods”. Technical Field

[0002] The present invention relates to the technical field of polysilicon, and in particular to a method and system for crushing electronic-grade polysilicon rods. Background Art

[0003] The Czochralski method melts polycrystalline silicon in a crucible and pulls single crystal silicon ingots from the melt to produce semiconductor devices. In the crucible, the polycrystalline silicon blocks often need to be crushed. Electronic-grade polycrystalline silicon produced by the vapor deposition method is a relatively large rod-shaped material, so after the polycrystalline silicon rods are produced, they need to be crushed. Electronic-grade polycrystalline silicon has extremely high purity requirements, reaching 10N to 11N (99.99999999% to 99.999999999%), so controlling impurity contamination is extremely important. Currently, both manual and mechanical crushing processes inevitably introduce various impurities.

[0004] Manual crushing offers flexibility but low efficiency, generating large amounts of dust during the process, posing a significant health hazard to workers. Mechanical crushing is more efficient, but the contaminants generated by mechanical friction and extrusion are more difficult to remove. Regardless of the method used, mechanical crushing inevitably introduces metallic impurities such as Fe (iron), Al (aluminum), and Na (sodium), contaminating the silicon material. Furthermore, due to the high hardness of silicon material, the equipment's crushing mechanism has a short lifespan and high maintenance costs.

[0005] The existing technology also exists in which the polycrystalline silicon rods are heated and rapidly cooled to obtain intercrystalline stress, thereby causing the silicon rods to break themselves. Although this method can reduce mechanical and manual intervention, the silicon rods will form more "hidden cracks" that are difficult to show in the broken pieces and will appear in the subsequent pickling and etching. At this time, the broken pieces with cracks will be picked out, re-crushed, and then pickled and etched, which requires frequent rework and reduces production efficiency.

[0006] In summary, the existing method for crushing polycrystalline silicon rods still needs to be improved.

[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 method and system for crushing electronic-grade polysilicon rods, 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 method for crushing electronic-grade polysilicon rods, comprising the following steps:

[0010] Step 1: Heating and rapidly cooling the polysilicon rod to generate cracks on its surface and inside;

[0011] Step 2: Place the polysilicon rods in a sealed container, evacuate the container, and inject an appropriate amount of water to fill the cracks and hidden cracks in the polysilicon rods;

[0012] Step 3: Drain the water in the sealed container and rapidly cool the polysilicon rods so that the water in the cracks and hidden cracks condenses into ice, thereby breaking the polysilicon rods;

[0013] Step 4: Return the polysilicon block to room temperature and remove the water.

[0014] Furthermore, in the step 1, when heating the polysilicon rod, the temperature is raised to 500-800 degrees Celsius and maintained for 10-20 minutes.

[0015] Furthermore, when the polycrystalline silicon rods are heated, the polycrystalline silicon rods are within the protection range of the inert gas.

[0016] Furthermore, when the polycrystalline silicon rods are heated, the heating rate of the polycrystalline silicon rods is controlled to be 10-30° C. / min.

[0017] Furthermore, in the step 1, when the polysilicon rods are rapidly cooled, they are quickly transferred to cold water, and the temperature of the cold water is 30 to 40 degrees Celsius.

[0018] Furthermore, in the step 2, when a proper amount of water is injected into the sealed container, the water surface is made to cover the top of the polysilicon rod.

[0019] Furthermore, in the step 2, after injecting a proper amount of water into the sealed container, the container is vibrated by an ultrasonic oscillator and maintained in a vacuum state.

[0020] Furthermore, in step three, the polysilicon rods are rapidly cooled by liquid nitrogen so that the temperature in the sealed container is lower than -50 degrees Celsius.

[0021] Furthermore, steps 2 to 4 are repeated several times.

[0022] The present invention also includes an electronic-grade polysilicon rod crushing system, using the crushing method described above, comprising:

[0023] A heating device, wherein the heating device heats the polysilicon rod;

[0024] A cooling device, wherein the cooling device cools the heated polysilicon rods;

[0025] A sealed container, wherein the sealed container is used to place polycrystalline silicon rods;

[0026] A vacuum device, which evacuates the sealed container;

[0027] A water filling and drainage device, which is used to fill or drain water into the closed container;

[0028] A quenching device is used to quench the closed container.

[0029] The beneficial effects of the present invention are as follows: the present invention first generates intercrystalline stress inside the polycrystalline silicon rod by heating and quenching the polycrystalline silicon rod, thereby generating cracks. The polycrystalline silicon rod is then placed in a sealed container, the sealed container is evacuated, and an appropriate amount of water is injected to allow the water to fill the cracks and hidden cracks in the polycrystalline silicon rod. The water in the sealed container is then quickly drained and the polycrystalline silicon rod is quenched, causing the water filling the internal cracks and hidden cracks to condense into ice. The water expands as it condenses into ice, while the polycrystalline silicon rod contracts due to cooling. The combined effects of internal expansion and external contraction are conducive to the expansion of the cracks in the polycrystalline silicon rod and the separation of silicon blocks, thereby achieving the effect of crushing the polycrystalline silicon rod. The present invention can save manpower, reduce contact between silicon material and people, and thus avoid contamination of the silicon material; do not require mechanical crushing, thereby reducing the introduction of metal impurities; and can reveal internal hidden cracks, avoiding multiple rework caused by the revealing of hidden cracks in the subsequent cleaning process, thereby improving crushing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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.

[0031] Figure 1 is a flow chart of the method of the present invention;

[0032] Figure 2 Schematic diagram of the structure of the system of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] 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”, etc., 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, rather than indicating or implying 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.

[0035] 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.

[0036] like Figure 1 A method for crushing electronic-grade polysilicon rods is shown, comprising the following steps:

[0037] Step 1: Heating and rapidly cooling the polysilicon rod to generate cracks on its surface and inside;

[0038] Step 2: Place the polysilicon rods in a sealed container, evacuate the container, and inject an appropriate amount of water to fill the cracks and hidden cracks in the polysilicon rods;

[0039] Step 3: Drain the water in the sealed container and rapidly cool the polysilicon rods so that the water in the cracks and hidden cracks condenses into ice, thereby breaking the polysilicon rods;

[0040] Step 4: Return the polysilicon block to room temperature and remove the water.

[0041] First, the polysilicon rods are heated and rapidly cooled to generate intercrystalline stress inside them, thereby generating cracks. The polysilicon rods are then placed in a sealed container, the sealed container is evacuated, and an appropriate amount of water is injected to allow the water to fill the cracks and hidden cracks in the polysilicon rods. The water in the sealed container is then quickly drained and the polysilicon rods are rapidly cooled, causing the water filling the internal cracks and hidden cracks to condense into ice. The water expands when it condenses into ice, while the polysilicon rods contract when cooled. The combined effects of internal expansion and external contraction are conducive to the expansion of the cracks in the polysilicon rods and the separation of silicon blocks, thereby achieving the effect of crushing the polysilicon rods. The present invention can save manpower, reduce contact between silicon materials and people, and thus avoid contamination of the silicon materials; no mechanical crushing is required, thereby reducing the introduction of metal impurities; and can reveal internal hidden cracks, avoiding multiple rework caused by the revealing of hidden cracks in subsequent cleaning processes, thereby improving crushing efficiency.

[0042] In this embodiment, in step 1, when heating the polysilicon rod, the temperature is raised to 500-800 degrees Celsius and maintained for 10-20 minutes.

[0043] When the polysilicon rods are heated, they are placed within the protection range of the inert gas.

[0044] When heating the polycrystalline silicon rod, the heating rate of the polycrystalline silicon rod is controlled to be 10 to 30° C. / min.

[0045] In step 1, when the polysilicon rods are rapidly cooled, they are quickly transferred to cold water with a water temperature of 30 to 40 degrees Celsius.

[0046] The silicon rods are first heated to a temperature of 500-800 degrees Celsius. During the heating process, the heating rate of the silicon rods is controlled to prevent them from heating too quickly. After reaching the required temperature, they are maintained for a period of time to ensure that the interior of the polysilicon rods has also reached the corresponding temperature, so that cracks can be generated further inside the silicon rods. Due to purity requirements, the polysilicon rods must be placed in an inert gas protection range during heating to prevent them from reacting with related substances in the air during the heating process. The inert gas can be nitrogen, helium, etc. After heating is completed, the silicon rods are quickly transferred to cold water with a water temperature controlled at 30-40 degrees Celsius to prevent cracks from forming on the silicon rods.

[0047] In step 2, a proper amount of water is injected into the sealed container so that the water surface covers the top of the polysilicon rod.

[0048] After pouring an appropriate amount of water into the sealed container, vibrate it with an ultrasonic oscillator and keep it vacuumed.

[0049] Since water is needed to fill the cracks and hidden cracks in the silicon rod, when injecting an appropriate amount of water into the closed container, the water surface needs to cover the top of the silicon rod, and the ultrasonic oscillator is used to oscillate to expel the air remaining in the deep cracks in the silicon rod to ensure that the water is filled more fully. During the oscillation of the ultrasonic oscillator, the closed container is kept vacuumed to expel the air.

[0050] In this embodiment, in step three, the polysilicon rods are rapidly cooled by liquid nitrogen so that the temperature in the sealed container is lower than -50 degrees Celsius.

[0051] After quickly draining the water from the sealed container, some water trapped in the cracks within the silicon ingots will also drain over time. Therefore, the silicon ingots need to be rapidly cooled with liquid nitrogen to minimize water loss from the cracks, thereby causing them to expand and break. After breaking, the silicon ingots are returned to room temperature, allowing the ice to melt and separate from the silicon ingots, helping to keep them clean. The broken silicon ingots will also need to be acid-washed in the subsequent process, but any remaining water will not have a negative impact.

[0052] In order to achieve sufficient crushing, steps 2 to 4 can be repeated several times.

[0053] like Figure 2 As shown, this embodiment also includes an electronic-grade polysilicon rod crushing system, using the crushing method as described above, including:

[0054] A heating device, which heats the polysilicon rods;

[0055] A cooling device, which cools the heated polysilicon rods;

[0056] A sealed container, which is used to place polysilicon rods;

[0057] Vacuum device, which evacuates the sealed container;

[0058] An injection and drainage device, which is used to inject or drain water into a closed container;

[0059] Quick cooling device: The quick cooling device quickly cools the closed container.

[0060] The device also includes an ultrasonic oscillator, which is arranged in a sealed container and performs ultrasonic oscillation on the sealed container to expel air from deep cracks in the silicon rods.

[0061] 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 method for crushing electronic-grade polysilicon rods, characterized in that: The steps include: Step 1: Heating and rapidly cooling the polysilicon rod to generate cracks on its surface and inside; Step 2: Place the polysilicon rods in a sealed container, evacuate the container, and inject an appropriate amount of water to fill the cracks and hidden cracks in the polysilicon rods; Step 3: Drain the water in the sealed container and rapidly cool the polysilicon rods so that the water in the cracks and hidden cracks condenses into ice, and then break the polysilicon rods into silicon blocks.

2. The electronic grade polysilicon rod crushing method according to claim 1, characterized in that: In the step 1, when heating the polysilicon rod, the temperature is raised to 500-800 degrees Celsius and maintained for 10-20 minutes.

3. The electronic grade polysilicon rod crushing method according to claim 2, characterized in that: When the polysilicon rods are heated, the polysilicon rods are placed within the protection range of the inert gas.

4. The electronic grade polysilicon rod crushing method according to claim 2, characterized in that: When heating the polycrystalline silicon rod, the heating rate of the polycrystalline silicon rod is controlled to be 10 to 30° C. / min.

5. The electronic grade polysilicon rod crushing method according to claim 1, characterized in that: In the step 1, when the polysilicon rods are rapidly cooled, they are quickly transferred to cold water, and the temperature of the cold water is 30 to 40 degrees Celsius.

6. The electronic grade polysilicon rod crushing method according to claim 1, characterized in that: In the step 2, when a proper amount of water is injected into the sealed container, the water surface is made to cover the top of the polysilicon rod; optionally, after injecting a proper amount of water into the sealed container, the container is vibrated by an ultrasonic oscillator and maintained in a vacuum state.

7. The electronic grade polysilicon rod crushing method according to claim 1, characterized in that: In the step three, the polysilicon rods are rapidly cooled by liquid nitrogen so that the temperature in the sealed container is lower than -50 degrees Celsius.

8. The electronic grade polysilicon rod crushing method according to claim 1, characterized in that: Also includes: Returning the silicon block to room temperature to allow the ice to melt and break away from the block, and The broken silicon blocks are pickled.

9. An electronic grade polysilicon rod crushing system, characterized in that: The crushing method according to any one of claims 1 to 8 comprises: A heating device, wherein the heating device heats the polysilicon rod; A cooling device, wherein the cooling device cools the heated polysilicon rods; A sealed container, wherein the sealed container is used to place polycrystalline silicon rods; A vacuum device, which evacuates the sealed container; A water filling and drainage device, which is used to fill or drain water into the closed container; A quenching device is used to quench the closed container.

10. The electronic-grade polysilicon rod crushing system according to claim 9, characterized in that: Also includes: An ultrasonic oscillator is disposed in the sealed container and is configured to perform ultrasonic oscillation on the sealed container to expel air from deep cracks in the polycrystalline silicon rods.

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