Czochralski silicon single crystal crucible and crystal pulling method

Abstract

The invention discloses a Czochralski silicon single crystal crucible and a crystal pulling method, and relates to the technical field of monocrystalline silicon manufacturing, the Czochralski silicon single crystal crucible comprises a crucible body, and the crucible body is made of tungsten. The crystal pulling method of the Czochralski silicon single crystal crucible comprises the following steps: placing the crucible on a thermal field crucible support of a single crystal furnace, and putting a material into the crucible; and setting the crucible rotation speed to be 7-9 revolutions and the furnace pressure to be 11-13 torrs, and carrying out crystal pulling treatment. The crucible body is made of tungsten instead of traditional quartz, oxygen-free crystal pulling is achieved, a crystal pulling process window can be opened, then the per unit area yield is improved, and it is guaranteed that a silicon rod is free of oxygen. Meanwhile, the tungsten crucible is longer in operation time, the limit that the operation time of a traditional quartz crucible is smaller than 600 hours is broken through, 1000-hour operation and repeated use can be achieved, and the crystal pulling non-silicon cost can be greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of single crystal silicon manufacturing, in particular to a Czochralski silicon single crystal crucible and a crystal pulling method. BACKGROUND

[0002] With years of technical development and iteration, N-type silicon wafers have become the mainstream in the solar monocrystalline silicon industry, but N-type silicon wafers have extremely strict requirements on oxygen content.

[0003] The prior art generally uses a quartz crucible (silicon dioxide material), and silicon dioxide releases oxygen atoms into the silicon melt at high temperature. High crucible rotation intensifies the reaction between the melt and the crucible wall, and high furnace pressure causes the oxygen in the molten silicon to be unable to quickly volatilize to the surface of the melt. To this end, the industry now uses a low crucible rotation and low furnace pressure process to improve oxygen into the crystal bar, but this extreme process causes difficulties in crystal formation during crystal pulling, temperature instability leads to a decrease in ignition and survival rate, and ultimately causes low single yield and high operating costs. This phenomenon is a difficulty in the industry at present. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide a Czochralski silicon single crystal crucible and a crystal pulling method.

[0005] To solve the above technical problems, the technical solutions of the present application are as follows: A Czochralski silicon single crystal crucible, comprising a crucible body, the material of the crucible body is tungsten.

[0006] The present application also provides a crystal pulling method for a Czochralski silicon single crystal crucible, comprising: Place the crucible on the single crystal furnace hot field crucible holder, and pour the material into the crucible; Set the crucible rotation to 7-9 revolutions and the furnace pressure to 11-13 torr, and perform crystal pulling treatment.

[0007] As a preferred solution of the crystal pulling method for the Czochralski silicon single crystal crucible of the present application, the crystal pulling treatment comprises: When the crucible is operated for 400-500 hours and the material at the bottom of the crucible is 20-30 kg, use a siphon device to suck out the material at the bottom of the crucible and perform material re-pouring.

[0008] As a preferred solution of the crystal pulling method for the Czochralski silicon single crystal crucible of the present application, the crystal pulling treatment further comprises: Stop the furnace after the crystal pulling time reaches a preset threshold, and allow the crucible to naturally slow down; Disassemble the furnace, perform pickling treatment on the inner surface of the crucible, and then pour the furnace to pull the crystal after drying.

[0009] As a preferred solution of the crystal pulling method for the Czochralski silicon single crystal crucible of the present application, the preset threshold of the crystal pulling time is 1000 h.

[0010] As a preferred scheme of the Czochralski silicon single crystal pulling method of the Czochralski silicon single crystal crucible, the natural slow cooling time of the crucible is 16h.

[0011] As a preferred scheme of the Czochralski silicon single crystal pulling method of the Czochralski silicon single crystal crucible, the acid cleaning agent used in the acid cleaning treatment is hydrofluoric acid.

[0012] The beneficial effects of the present application are: (1) The material of the crucible body is replaced by tungsten instead of traditional quartz, and the silicon melt and the tungsten crucible will not react at high temperature, which can effectively prevent the high oxygen content and the high concentric circle of the silicon wafer battery in the crystal pulling process, thereby realizing oxygen-free crystal pulling, expanding the crystal pulling process window, and further improving the single yield and ensuring zero oxygen of the silicon rod.

[0013] (2) The tungsten crucible provided by the present application has a longer running time, breaks the traditional quartz crucible running limit of <600 hours, and can realize 1000 hours of running, effectively improving the crystal pulling efficiency.

[0014] (3) The tungsten crucible provided by the present application realizes the reuse of the crucible in the crystal pulling process, which can greatly reduce the non-silicon cost of crystal pulling.

[0015] (4) The present application effectively solves the problem of high frequency of thermal field disassembly and cleaning, and realizes the simplification of the operating personnel. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 The structure schematic diagram of the Czochralski silicon single crystal crucible provided by the present application is shown in the figure. 1, crucible body. DETAILED DESCRIPTION

[0018] In order to make the content of the present application more easily understood, the following will make a further detailed description of the present application according to the specific embodiments and in combination with the drawings.

[0019] Figure 1 The structure schematic diagram of the Czochralski silicon single crystal crucible provided by the present application is shown in the figure. The Czochralski silicon single crystal crucible includes a crucible body 1. The material of the crucible body 1 is tungsten.

[0020] The material of the crucible body 1 is replaced by tungsten instead of traditional quartz, and the silicon melt and the tungsten crucible will not react at high temperature, which can effectively prevent the high oxygen content and the high concentric circle of the silicon wafer battery in the crystal pulling process, thereby realizing oxygen-free crystal pulling, opening the crystal pulling process window, and further improving the single yield and ensuring zero oxygen of the silicon rod.

[0021] The application also provides a crystal pulling method of a straight-pulling silicon single crystal crucible, which comprises the following steps: Step S101: Place the crucible on the single crystal furnace hot field crucible holder, and pour the material into the crucible.

[0022] Specifically, after the furnace table is cleaned, the tungsten crucible is placed on the single crystal furnace hot field crucible holder, and the material is poured.

[0023] Step S102: Set the crucible rotation to 7-9 revolutions, and set the furnace pressure to 11-13 Torr, and perform the crystal pulling process.

[0024] Specifically, after the material is poured, the crystal pulling process with large crucible rotation and high furnace pressure is adopted to improve the crystal formation problem of large-size crystal rods. Since the tungsten crucible cannot release oxygen atoms, a relatively wide process window can be used for crystal pulling.

[0025] In this embodiment, the crucible rotation is set to 7-9 revolutions, and the furnace pressure is set to 11-13 Torr.

[0026] In the crystal pulling process, since long-time operation in the crystal pulling process will cause high impurity content of the molten silicon at the bottom of the crucible, which will affect the service life of the crystal rod, therefore, when the crucible is operated for 400-500 hours and the material at the bottom of the crucible is 20-30 kg, the siphon device is used to suck out the material at the bottom of the crucible, and then the material is re-poured.

[0027] In addition, the furnace needs to be stopped after the crystal pulling time reaches the preset threshold. The tungsten crucible has high strength and good corrosion resistance under the protection of vacuum inert gas, and the furnace is stopped for a period of time to allow the tungsten crucible to naturally and slowly cool down, then the furnace is disassembled, the inner surface of the crucible is pickled, and the furnace is re-poured after drying.

[0028] In this embodiment, the preset threshold of the above-mentioned crystal pulling time is 1000h. The natural slow cooling time of the crucible is 16h. The acid cleaning agent used in the pickling process is hydrofluoric acid.

[0029] Therefore, the technical scheme of the application replaces the material of the crucible body with tungsten instead of traditional quartz, realizes oxygen-free crystal pulling, opens the crystal pulling process window, further improves the single yield, and ensures zero oxygen of the silicon rod. At the same time, the tungsten crucible has a longer operation time, breaks the traditional quartz crucible operation limit of <600 hours, can realize 1000 hours of operation, and can be repeatedly used, which can greatly reduce the non-silicon cost of crystal pulling.

[0030] In addition to the above embodiments, the present application can also have other implementation manners; any technical solutions formed by equivalent replacement or equivalent transformation shall fall within the protection scope required by the present application.

Claims

1. A Czochralski silicon single crystal crucible, characterized by: The crucible comprises a crucible body (1) made of tungsten.

2. A Czochralski method of growing a silicon single crystal based on the crucible of claim 1, characterized in that: The method comprises the following steps: Placing the crucible on a single crystal furnace hot field crucible holder and putting the material into the crucible; Setting the crucible rotation to 7-9 revolutions and the furnace pressure to 11-13 torr to perform the crystal pulling process.

3. The single crystal silicon ingot pulling process of claim 2, wherein: The crystal pulling process comprises: When the crucible is operated for 400-500 hours and the material in the crucible bottom is 20-30 kg, the siphon device is used to suck out the material in the crucible bottom and the material is re-injected.

4. The single crystal silicon ingot pulling process of claim 3, wherein: The crystal pulling process further comprises: Stopping the furnace after the crystal pulling time reaches a preset threshold, and naturally slow cooling the crucible; Disassembling the furnace to perform acid pickling treatment on the inner surface of the crucible, drying, and then re-injecting the furnace to pull the crystal.

5. The single crystal silicon ingot pulling process of claim 4, wherein: The preset threshold of the crystal pulling time is 1000 h.

6. The single crystal silicon ingot pulling process of claim 4, wherein: The natural slow cooling time of the crucible is 16 h.

7. The single crystal silicon ingot pulling process of claim 4, wherein: The acid cleaning agent used in the acid pickling treatment is hydrofluoric acid.

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