Monocrystalline silicon furnace heating device

Abstract

The utility model relates to the technical field of monocrystalline silicon production equipment, and particularly discloses a monocrystalline silicon furnace heating device. A bottom heater is horizontally arranged at the bottom of the monocrystalline silicon furnace heat preservation barrel, a cylindrical middle heater is arranged in the monocrystalline silicon furnace heat preservation barrel along the side wall, and a cylindrical upper heater is arranged above the middle heater in an equal-diameter mode. An integral heating thermal field is formed by the bottom heater, the middle heater and the upper heater, so that the heating power can be more accurately controlled when a silicon material is heated, the heating area is larger and more uniform, the duration of a material melting stage is effectively shortened, and the precipitation of oxygen in the quartz crucible caused by long-time heating is reduced; and in the crystal pulling process, the whole heating device can cover the whole moving area of the crucible, so that the crucible is heated, and the crystallization of the silicon material is more stable.

Description

Technical field:

[0001] The utility model relates to the technical field of single crystal silicon production equipment, in particular to a single crystal silicon furnace heating device. Background technology:

[0002] The production of single crystal silicon often adopts the Czochralski process: the silicon raw material is loaded into a quartz crucible and heated to melt, and then the temperature is controlled to near the melting point of single crystal silicon, and the crystal is pulled by rotation using a seed crystal; the heating is generally carried out electrically with a graphite heater, and the temperature of each stage is controlled by controlling the power of the heater.

[0003] During the heating and melting process, the quartz crucible reacts with the silicon raw material to produce silicon oxide incorporation. The precipitated oxygen atoms enter the crystal rod by segregation during the crystallization process, resulting in a higher oxygen content in the finished crystal rod. It is usually necessary to reduce the oxygen content in the single crystal silicon rod by controlling multiple factors such as the pulling speed, crucible speed, heat field temperature and melting time. According to production experience, shortening the melting time and keeping the heat field temperature uniform and stable during the crystal pulling process can better control the oxygen content. However, the existing heaters are generally single-chip parallel heaters, and the heating power of the heaters at different positions is different, resulting in poor heating uniformity. In addition, during the crystal pulling process, as the liquid level in the crucible drops, the crucible needs to move upward to track the liquid level. At this time, the main heating area of ​​the heater is offset relative to the crucible, and the thermal field changes, affecting the crystal ingot crystallization. In addition, since the crucible is thin on all sides and has a high heat transfer efficiency, the traditional heating device is only arranged circumferentially around the crucible, resulting in the silicon material near the top and the outer wall of the crucible melting first during the melting process, and the bottom needs to be heated by heat transfer from the molten silicon material, resulting in a longer melting time. The molten silicon material is in contact with the quartz crucible for a long time, resulting in an increase in the oxygen content of the upper silicon material. Utility model content:

[0004] The utility model aims to provide a single crystal silicon furnace heating device to provide a uniform and stable thermal field and control the oxygen content in the single crystal silicon rod.

[0005] The utility model is implemented by the following technical scheme: a single crystal silicon furnace heating device comprises a bottom heater, a middle heater and an upper heater; a bottom heater is horizontally arranged at the bottom of a heat preservation barrel of the single crystal silicon furnace, a cylindrical middle heater is arranged inside the heat preservation barrel of the single crystal silicon furnace and along the side wall, a cylindrical upper heater is arranged with equal diameter above the middle heater, the bottom heater is symmetrically provided with two first electrode ears, the middle heater is symmetrically provided with two second electrode ears, the upper heater is symmetrically provided with two third electrode ears, the first electrode ears, the second electrode ears and the third electrode ears are arranged in a staggered manner, and are respectively connected to the electrode columns at the bottom of the heat preservation barrel of the single crystal silicon furnace.

[0006] Furthermore, the bottom heater comprises a bottom heating plate that is wound in a ring-like serpentine shape and a first electrode ear. The first electrode ears are symmetrically integrally formed at both ends of the bottom heating plate, and a circular hole is provided in the middle of the bottom heating plate.

[0007] Furthermore, the central heater includes two groups of semi-cylindrical central heating plates, each group of central heating plates includes two mirror-symmetrical central heating parts, the central heating parts are in a serpentine shape that continuously winds up and down, the two central heating parts are connected by connecting ears, and the two groups of central heating plates are connected by two first column feet, and the bottom of the first column foot is integrally formed with a second electrode ear.

[0008] Furthermore, the upper heater includes two semi-cylindrical top heating plates, each of which is in a serpentine shape that continuously winds up and down, and the two top heating plates are connected by two second column feet. The second column feet extend downward and pass between the two middle heating parts of the middle heating plate, and a third electrode ear is integrally formed at the bottom of the second column feet.

[0009] Furthermore, a first protrusion is provided at the position where the middle heating part and the connecting ear are connected, at the position where the top heating plate and the second column foot are connected, and at the position where the middle heating part and the first column foot are connected. Second protrusions overlapping the corresponding first protrusions are provided on the connecting ear, the second column foot and the first column foot. The first protrusion and the second protrusion are fixedly connected by inserting graphite bolts.

[0010] The utility model has the advantages that the bottom heater, the middle heater and the upper heater form an overall thermal field, so that when heating the silicon material, the heating power can be controlled more accurately, the heating area is larger and more uniform, the duration of the material-forming stage is effectively shortened, and the precipitation of oxygen in the quartz crucible caused by long-term heating is reduced; and during the crystal pulling process, the entire heating device can cover the entire area where the crucible moves, and the crucible is always kept heated, thereby ensuring that the crystallization of the silicon material is more stable. Description of the drawings:

[0011] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0012] Figure 2 This is a schematic diagram of the structure of the bottom heater.

[0013] Figure 3 It is a schematic diagram of the structure of the middle heater.

[0014] Figure 4 It is a schematic diagram of the structure of the middle heating plate.

[0015] Figure 5 It is a schematic diagram of the structure of the upper heater.

[0016] Figure 6It is a schematic diagram of the local structure of the connection between the middle heating part and the top heating plate and the first column foot and the second column foot.

[0017] Figure 7 It is a schematic diagram of the local structure of the connection between the middle heating part and the connecting ear.

[0018] In the figure: bottom heater 1, middle heater 2, upper heater 3, single crystal silicon furnace insulation barrel 4, first protrusion 5, second protrusion 6, bottom heating plate 101, first electrode ear 102, round hole 103, middle heating part 201, connecting ear 202, first column foot 203, second electrode ear 204, top heating plate 301, second column foot 302, third electrode ear 303. Specific implementation method:

[0019] The following will be combined with the drawings of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0020] In the description of the present invention, it should be noted that the terms "center", "up", "down", "front", "back", "top", "bottom", "left", "right", "vertical", "horizontal", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions 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 direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0021] like Figure 1As shown: a single crystal silicon furnace heating device, which includes a bottom heater 1, a middle heater 2 and an upper heater 3; the bottom heater 1 is horizontally arranged at the bottom of the single crystal silicon furnace insulation barrel 4, a cylindrical middle heater 2 is arranged inside the single crystal silicon furnace insulation barrel 4 and along the side wall, and a cylindrical upper heater 3 is arranged above the middle heater 2 with equal diameters, the bottom heater 1 is symmetrically provided with two first electrode ears 102, the middle heater 2 is symmetrically provided with two second electrode ears 204, and the upper heater 3 is symmetrically provided with two third electrode ears 303, the first electrode ears 102, the second electrode ears 204 and the third electrode ears 303 are arranged in a staggered manner and are respectively connected to the electrode columns at the bottom of the single crystal silicon furnace insulation barrel 4; in the stage of material fusion, the crucible is at the lowest position, at this time, through the bottom The upper heater 1 and the middle heater 2 heat and melt the silicon material in the crucible, and the surroundings and the bottom of the crucible are evenly heated. The silicon material in the crucible has a large heating area and high heat transfer efficiency, which can accelerate the melting of the silicon material, thereby shortening the heating time, reducing the reaction between the quartz crucible and the silicon material, thereby reducing the precipitation of oxygen, and effectively reducing the oxygen content in the finished crystal rod; in the crystal pulling stage, the liquid level in the crucible gradually decreases, and the crucible gradually rises, exceeding the stable heating range of the middle heater 2, and enters the heating area of ​​the upper heater 3. At this time, the upper heater 3 is turned on as needed, and the power of each heater is controlled at the same time, which can better maintain the temperature of the silicon material in the crucible at the optimal crystallization temperature, so that the crystallization effect of the silicon material is more stable, and it is convenient to control the oxygen content of the final crystal rod.

[0022] like Figure 2 As shown: the bottom heater 1 includes a bottom heating plate 101 and a first electrode ear 102 that are wound in a ring-like serpentine shape. The first electrode ears 102 are symmetrically integrally formed at both ends of the bottom heating plate 101. A circular hole 103 is provided in the middle of the bottom heating plate 101. The middle of the circular hole 103 is used to pass a support rod that supports the rotation and lifting of the crucible. The bottom heating plate 101 does not conflict with the position of the support rod. The main heating area is connected in series between the two first electrode ears 102. The bottom heating plate 101 is in a ring-like serpentine shape, which can make the heat generation more uniform.

[0023] like Figure 3 , Figure 4As shown: the middle heater 2 includes two groups of semi-cylindrical middle heating plates, each group of middle heating plates includes two mirror-symmetrical middle heating parts 201, the middle heating part 201 is in the shape of a snake that continuously winds up and down, so that the heat is more uniform, the two middle heating parts 201 are connected by a connecting ear 202, and the four middle heating parts 201 can be replaced separately when they are damaged, the two groups of middle heating plates are connected in parallel through two first column feet 203, and the bottom of the first column foot 203 is integrally formed with a second electrode ear 204, the first column foot 203 acts as a conductor to conduct current, and is also a structural member supporting the two groups of middle heating plates, so that they are fixed in the single crystal silicon furnace insulation barrel 4 through the second electrode ear 204 at the bottom of the first column foot 203; the two groups of semi-cylindrical middle heating plates form a cylindrical whole to heat the periphery of the crucible.

[0024] like Figure 5 As shown: the upper heater 3 includes two semi-cylindrical top heating plates 301, each of which is in a serpentine shape that winds up and down continuously, and the two top heating plates 301 are connected by two second column feet 302, and the second column feet 302 extend downward and pass through between the two middle heating parts 201 of the middle heating plate, and a third electrode ear 303 is integrally formed at the bottom of the second column feet 302, and the connecting ear 202 fixedly connected between the two middle heating parts 201 bypasses the second column feet 302 and the third electrode ear 303, and the connecting ear 202 does not contact the third electrode ear 303 and the bottom heating plate 101; the two semi-cylindrical top heating plates 301 form a cylindrical whole, and the two top heating plates 301 are connected in parallel to heat the periphery of the crucible.

[0025] like Figure 6 , Figure 7As shown: a first protrusion 5 is provided at the position where the middle heating part 201 and the connecting ear 202 are connected, at the position where the top heating plate 301 and the second column foot 302 are connected, and at the position where the middle heating part 201 and the first column foot 203 are connected. A second protrusion 6 overlapping the corresponding first protrusion 5 is provided on the connecting ear 202, the second column foot 302 and the first column foot 203. The first protrusion 5 and the second protrusion 6 are fixedly connected by passing through a graphite bolt 7; the first protrusion 5 and the second protrusion 6 can increase the contact area, reduce the contact resistance, and avoid serious heating and burning caused by excessive resistance at the connection part. The graphite bolt 7 has It has the characteristic of high temperature resistance, and the first protrusion 5 and the second protrusion 6 are locked with each other to prevent the first protrusion 5 and the second protrusion 6 from being falsely connected and overheated and burned; the middle heater 2 and the upper heater 3 are both cylindrical as a whole. Since the graphite material is brittle and has low mechanical strength, it is very easy to be damaged or cracked during transportation as a whole. Therefore, during transportation, the middle heater 2 can be split into a quarter-cylindrical middle heating part 201 and a half-cylindrical top heating plate 301 for easy transportation. During on-site installation, it is overlapped and assembled with the first column foot 203 and the second column foot 302 through the first protrusion 5 and the second protrusion 6.

Claims

1. A single crystal silicon furnace heating device, characterized in that: The invention comprises a bottom heater (1), a middle heater (2) and an upper heater (3); the bottom heater (1) is horizontally arranged at the bottom of a single crystal silicon furnace heat preservation barrel (4); a cylindrical middle heater (2) is arranged inside the single crystal silicon furnace heat preservation barrel (4) and along the side wall; a cylindrical upper heater (3) is arranged above the middle heater (2) with equal diameter; the bottom heater (1) is symmetrically provided with two first electrode ears (102); the middle heater (2) is symmetrically provided with two second electrode ears (204); and the upper heater (3) is symmetrically provided with two third electrode ears (303); the first electrode ears (102), the second electrode ears (204) and the third electrode ears (303) are arranged in a staggered manner and are respectively connected to electrode columns at the bottom of the single crystal silicon furnace heat preservation barrel (4).

2. A single crystal silicon furnace heating device according to claim 1, characterized in that: The bottom heater (1) comprises a bottom heating plate (101) winding in a ring-like serpentine shape and a first electrode ear (102), the first electrode ears (102) being symmetrically integrally formed at both ends of the bottom heating plate (101), and a circular hole (103) being provided in the middle of the bottom heating plate (101).

3. The single crystal silicon furnace heating device according to claim 1, characterized in that: The middle heater (2) comprises two groups of semi-cylindrical middle heating plates, each group of middle heating plates comprises two mirror-symmetrical middle heating parts (201), the middle heating parts (201) are in a serpentine shape that winds up and down continuously, the two middle heating parts (201) are connected via connecting ears (202), the two groups of middle heating plates are connected via two first column feet (203), and the bottom of the first column feet (203) is integrally formed with a second electrode ear (204).

4. A single crystal silicon furnace heating device according to claim 3, characterized in that: The upper heater (3) comprises two semi-cylindrical top heating plates (301), each top heating plate (301) is in a serpentine shape that winds continuously up and down, and the two top heating plates (301) are connected via two second column feet (302), the second column feet (302) extend downward and pass between two middle heating parts (201) of the middle heating plate, and a third electrode ear (303) is integrally formed at the bottom of the second column feet (302).

5. The single crystal silicon furnace heating device according to claim 4, characterized in that: A first protrusion (5) is provided at a position where the middle heating portion (201) and the connecting ear (202) are connected, at a position where the top heating plate (301) and the second column foot (302) are connected, and at a position where the middle heating portion (201) and the first column foot (203) are connected. A second protrusion (6) overlapping the corresponding first protrusion (5) is provided on the connecting ear (202), the second column foot (302) and the first column foot (203). The first protrusion (5) and the second protrusion (6) are fixedly connected by passing a graphite bolt (7).

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