Bottom heater with corrosion retarding function for Czochralski method single crystal production

Abstract

The utility model discloses a Czochralski method single crystal production bottom heater with a corrosion retarding function, and particularly relates to the field of single crystal production, the Czochralski method single crystal production bottom heater comprises a bottom heating area, bottom foot adding plates and connecting blocks, the two sides of the bottom heating area are respectively connected with the bottom foot adding plates through the connecting blocks, the bottom heating area comprises a heating ring and a heating disc, and the heating ring is connected with the bottom foot adding plates through the connecting blocks. Heating plates are symmetrically welded to the two sides of the heating ring with the center of the heating ring as the center, the heating ring is in an annular shape, each heating plate is of an S-shaped structure, the heating plates and the heating ring are connected to form heating strips, and connecting holes are formed in the bottom foot adding plate. The thickness of the bottom heater foot plate and the thickness of the joint of the bottom heater foot plate and the heater are increased, and gradual transition is achieved through the trapezoidal bevel, so that temperature rise caused by local increase of local resistance is improved, and hot corrosion of high temperature to the bottom heater joint is reduced; the thickness is increased, the mechanical strength of the bottom heater is improved, scouring of airflow to the bottom heater is relieved, and the service life is effectively prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of single crystal production, and more specifically to a bottom heater for single crystal production by a Czochralski method with the function of slowing down corrosion. Background Art

[0002] Single crystal silicon is the basic material of the modern semiconductor industry and occupies an important position in the national economy. Single crystal silicon is grown from quartz sand as raw material. The earth's crust is rich in silicon, and its natural abundance is second only to oxygen. After coke carbon reduction and other chemical purification methods to increase the purity of silicon to 8 "9" after the decimal point, the single crystal silicon rod is pulled by the Czochralski method or the zone melting method to produce semiconductor-grade single crystal silicon, and then semiconductor single crystal silicon wafers are obtained through slicing, flooding, polishing, cleaning and other processes.

[0003] At present, the preparation of single crystal silicon mainly adopts the Czochralski method. The Czochralski method is to place polycrystalline silicon material in a single crystal furnace, and heat it to above 1420℃ to melt the polycrystalline silicon material, and then complete the growth of silicon single crystal through a series of processes such as seeding, necking, shouldering, equal diameter, and finishing. The impurity distribution in the single crystal silicon grown by the Czochralski method is relatively uniform, with high mechanical strength and strong internal impurity absorption ability, which makes it widely used in electronic devices and integrated circuits.

[0004] The thermal field used in the single crystal furnace includes a main heater and a bottom heater. Currently, the bottom heater of the single crystal furnace adopts an isostatic graphite process and mostly uses a series structure with the same overall height.

[0005] However, since the bottom heater is divided into two parts, the foot plate and the heating zone, the current passing through the junction of the foot plate and the electrode is relatively large, the cross-sectional area of ​​the bottom foot plate is large, and the bottom heating zone is a heating strip with a smaller diameter to ensure the heating area and control the target resistance. Relative to the cross-sectional area of ​​the connection between the bottom heating zone and the bottom foot plate, the cross-sectional area suddenly shrinks when the current passes through the bottom foot plate toward the bottom heating zone, the local resistance is relatively large, the voltage and current remain unchanged, the heat is high, the local thermal corrosion of the bottom heater is increased, and the service life of the bottom heater is affected. Therefore, a bottom heater for CZ single crystal production with corrosion reduction function is proposed. Utility Model Content

[0006] In order to overcome the above defects of the prior art, the utility model provides a bottom heater for CZ single crystal production with corrosion mitigation function, by increasing the thickness of the bottom heater foot plate and the thickness of the connection between the bottom heater foot plate and the heater. Through the gradual transition of the trapezoidal bevel, the temperature rise caused by the local increase of the local resistance is improved, the thermal corrosion of the bottom heater connection by high temperature is reduced, the thickness is increased, the mechanical strength of the bottom heater is improved, the scouring of the bottom heater by the airflow is alleviated, and the service life is effectively increased, so as to solve the problems raised in the above background technology.

[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solution: a bottom heater for Czochralski single crystal production with corrosion mitigation function, comprising a bottom heating zone, a bottom foot plate and a connecting block, wherein both sides of the bottom heating zone are connected to the bottom foot plate through the connecting blocks.

[0008] Preferably, the bottom heating area includes a heating ring and a heating plate, and heating plates are welded on both sides of the heating ring in a symmetrical manner with the center of the heating ring. The heating ring is ring-shaped, and the heating plate is S-shaped. The heating plate is connected to the heating ring to form a heating strip.

[0009] Preferably, the bottom foot plate is provided with a connection hole, and the connection hole is used to connect with the electrode in the single crystal furnace.

[0010] Preferably, the connecting block is of a trapezoidal structure, and the end of the connecting block with a larger cross-sectional dimension is connected to the bottom footing plate, and the end of the connecting block with a smaller cross-sectional dimension is connected to one end of the heating plate.

[0011] Preferably, the cross-sectional area of ​​the bottom foot plate is larger than the cross-sectional area of ​​the heating strip.

[0012] Preferably, the cross-sectional area of ​​the bottom foot plate is larger than the cross-sectional area of ​​the heating strip, and the cross-sectional area of ​​the bottom foot plate is smoothly connected to the cross-sectional area of ​​the heating strip through a connecting block.

[0013] Beneficial effects of the utility model:

[0014] The utility model increases the thickness of the bottom heater foot plate and the thickness of the connection between the bottom heater foot plate and the heater, and gradually transitions through a trapezoidal bevel, thereby improving the temperature increase caused by the local increase of local resistance and reducing thermal corrosion of the bottom heater connection caused by high temperature; increasing the thickness, improving the mechanical strength of the bottom heater, alleviating the scouring of the bottom heater by the airflow, and effectively prolonging the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0016] Figure 2 It is a side structural schematic diagram of the utility model.

[0017] The accompanying drawings are marked as: 1. heating area at the bottom; 2. foot plate at the bottom; 3. connecting block. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments 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 in 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.

[0019] As attached Figure 1-2 The bottom heater for Czochralski single crystal production with corrosion mitigation function shown in the figure comprises a bottom heating zone 1, a bottom foot plate 2 and a connecting block 3, the bottom heating zone 1 is connected to the bottom foot plate 2 on both sides through the connecting block 3 respectively, the bottom heating zone 1 comprises a heating ring and a heating plate, the heating ring is welded with heating plates on both sides in a centrally symmetrical manner with the center of the heating ring, the heating ring is ring-mounted, the heating plate is in an S-shaped structure, the heating plate is connected to the heating ring to form a heating strip, the bottom foot plate 2 is provided with a connecting hole, the connecting hole is used to connect with the electrode in the single crystal furnace, the connecting block 3 is in a trapezoidal structure, and the end of the connecting block 3 with a larger cross-sectional dimension is connected to the bottom foot plate 2, and the end of the connecting block 3 with a smaller cross-sectional dimension is connected to one end of the heating plate, the cross-sectional area of ​​the bottom foot plate 2 is larger than the cross-sectional area of ​​the heating strip, and the cross-sectional area of ​​the bottom foot plate 2 is smoothly connected to the cross-sectional area of ​​the heating strip through the connecting block 3.

[0020] Working principle of the utility model: in order to improve the service life of the bottom heater, by increasing the thickness of the bottom foot plate 2 and the thickness of the connection between the bottom foot plate and the bottom heating zone 1, due to the connection between the bottom heater foot plate and the electrode, the current passing through is large, the cross-sectional area of ​​the bottom foot plate is large, the bottom heating zone is to ensure the heating area and control the target resistance, the heating zone is a heating strip with a smaller diameter, the cross-sectional area suddenly shrinks when the current passes through the bottom foot plate toward the bottom heating zone, the local resistance is large, the voltage and current remain unchanged, the resistance is large, the heat is high, the local thermal corrosion of the bottom heater is increased, and the service life of the bottom heater is affected. The bottom heater of the utility model increases the cross-sectional area of ​​the connection of the bottom foot plate 2, and gradually transitions by using the trapezoidal oblique structure formed by the connecting block 3, improves the temperature increase caused by the local increase of the local resistance, thereby reducing the thermal corrosion of the bottom connection caused by high temperature, and by increasing the thickness of the bottom foot plate 2, the mechanical strength of the bottom heater is improved, and the scouring of the bottom heater by the airflow is alleviated.

[0021] The utility model increases the thickness of the connection between the bottom heater foot plate and the heater, thereby effectively reducing the sudden change of resistance, concentrating the current, and adjusting the local bottom thickness. The total resistance value of the bottom heater is normal, the heat generation is normal, and the service life is effectively improved.

[0022] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A bottom heater for Czochralski single crystal production with corrosion mitigation function, comprising a bottom heating zone (1), a bottom foot plate (2) and a connecting block (3), characterized in that: Both sides of the bottom heating area (1) are connected to bottom foot plates (2) via connecting blocks (3); The connecting block (3) has a trapezoidal structure, and the end of the connecting block (3) with a larger cross-sectional dimension is connected to the bottom foot plate (2), while the end of the connecting block (3) with a smaller cross-sectional dimension is connected to one end of the heating plate.

2. The bottom heater for Czochralski single crystal production with corrosion mitigation function according to claim 1, characterized in that: The bottom heating zone (1) comprises a heating ring and a heating plate, the heating plates are welded on both sides of the heating ring in a centrally symmetrical manner with the center of the heating ring, the heating ring is ring-shaped, the heating plate is in an S-shaped structure, and the heating plate is connected to the heating ring to form a heating strip.

3. The bottom heater for Czochralski single crystal production with corrosion mitigation function according to claim 1, characterized in that: The bottom foot plate (2) is provided with a connection hole, and the connection hole is used to connect with the electrode in the single crystal furnace.

4. The bottom heater for Czochralski single crystal production with corrosion mitigation function according to claim 1, characterized in that: The cross-sectional area of ​​the bottom foot plate (2) is larger than the cross-sectional area of ​​the heating strip, and the cross-sectional area of ​​the bottom foot plate (2) is smoothly connected to the cross-sectional area of ​​the heating strip via the connecting block (3).

Images