Boron diffusion process using graphite sealing gasket

Abstract

The present invention discloses a boron diffusion process method using a graphite sealing gasket. The following structure is adopted in the furnace mouth of the process chamber for boron diffusion: a sealing flange is provided on the outside of the furnace mouth of the process chamber, the sealing flange is fixedly mounted on a frame and presses the furnace mouth of the process chamber, and a quartz furnace door is pressed on the outside of the sealing flange; an outer ring groove and an inner ring groove are provided on the surface of the sealing flange opposite to the furnace mouth, a graphite sealing gasket is installed in the outer ring groove, a ceramic fiber packing is installed in the inner ring groove, the graphite sealing gasket realizes the vacuum sealing of the furnace mouth, and the ceramic fiber packing isolates the graphite sealing gasket from polluting the silicon wafer. The sealing flange structure of the present invention adopts a graphite sealing gasket, which can withstand higher temperatures compared to the traditional sealing flange using a rubber sealing ring, and there is no need to worry about the high temperature damage of the sealing ring; at the same time, due to the isolation effect of the ceramic fiber packing, the possible pollution of the process chamber by the graphite gasket is effectively prevented.

Description

Technical Field

[0001] The invention relates to the technical field of solar cell manufacturing, in particular to a boron diffusion process method using a graphite sealing gasket. Background Art

[0002] Solar photovoltaic cells are a new type of battery that converts sunlight directly into electrical energy. Currently, silicon photovoltaic cells based on silicon are commonly used, including single-crystal silicon, polycrystalline silicon and amorphous silicon photovoltaic cells. In the preparation process of solar photovoltaic cells, silicon wafers need to go through processes such as texturing, diffusion, etching, coating and printing in sequence. In the preparation process of photovoltaic cells, a sealing flange is usually installed between the process chamber of the boron diffusion furnace and the quartz furnace door, and the sealing flange is installed at the furnace door to achieve effective sealing with the process chamber.

[0003] The existing water-cooled flange seal uses a single or double layer of fluororubber sealing ring for sealing, which is suitable for conditions where the process temperature is not very high and the inner diameter of the process chamber is less than or equal to φ450. When the process temperature rises to above 1000℃ and the inner diameter of the process chamber is greater than or equal to φ450, the rubber sealing ring on the existing sealing flange is subjected to high temperature baking during each silicon wafer opening and unloading process. The fluororubber sealing ring is prone to aging and cracking, and its service life is very short, which greatly increases the operating cost of the production line and reduces production efficiency. Summary of the invention

[0004] In view of the shortcomings of the above-mentioned existing water-cooled flange sealing structure, such as easy aging, cracking and short service life at high temperatures, the applicant provides a boron diffusion process method using graphite sealing gaskets. Graphite gaskets are used to achieve vacuum sealing, which can withstand higher temperatures. Ceramic fiber packings are used to isolate the graphite gaskets from contamination of silicon wafers, thereby improving their stability and reliability.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A boron diffusion process method using a graphite sealing gasket, wherein the furnace mouth of a process chamber for boron diffusion adopts the following structure, wherein a sealing flange is arranged on the outer side of the furnace mouth of the process chamber, the sealing flange is fixedly mounted on a frame and presses the furnace mouth of the process chamber, and a quartz furnace door is pressed on the outer side of the sealing flange; an outer ring groove and an inner ring groove are provided on the surface of the sealing flange opposite to the furnace mouth, a graphite sealing gasket is installed in the outer ring groove, a ceramic fiber packing is installed in the inner ring groove, the graphite sealing gasket realizes vacuum sealing of the furnace mouth, and the ceramic fiber packing isolates the graphite sealing gasket from contaminating a silicon wafer.

[0007] As a further improvement of the above technical solution:

[0008] A sealing groove is provided on the inner side of the quartz furnace door, a sealing ring is installed in the sealing groove, and the quartz furnace door and the sealing flange are sealed by the sealing ring.

[0009] The sealing flange realizes vacuum sealing between the sealing flange and the process chamber by extruding a graphite sealing gasket.

[0010] Ceramic fiber packing forms a barrier between the vacuum chamber and the graphite seal.

[0011] The number of outer ring grooves is 1-2.

[0012] When the number of the outer ring grooves is more than two, they are distributed in inner and outer concentric circles.

[0013] The number of inner ring grooves is 1-2.

[0014] When the number of inner grooves is more than two, they are distributed in inner and outer concentric circles.

[0015] The sealing flange is fixed to the frame by screws.

[0016] The quartz furnace door is pressed against the outer side of the sealing flange by the driving cylinder.

[0017] The beneficial effects of the present invention are as follows:

[0018] The present invention adopts a sealing flange structure equipped with a graphite sealing gasket. Compared with the traditional sealing flange using a rubber sealing ring, it can withstand higher temperatures and there is no need to worry about the high temperature damage of the sealing ring. At the same time, due to the isolation effect of the ceramic fiber packing, the graphite gasket can effectively prevent the possible pollution of the process chamber. The use of graphite gasket sealing can withstand higher temperatures under the same process conditions, with lower costs and more stable structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the present invention.

[0020] Figure 2 for Figure 1 Enlarged view of part A.

[0021] In the figure: 1. furnace mouth; 2. ceramic fiber packing; 3. graphite sealing gasket; 4. sealing flange; 5. quartz furnace door. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0023] like Figure 1 to Figure 2As shown, the boron diffusion process method using graphite sealing gaskets of the present invention adopts the following structure at the furnace mouth of the process chamber for boron diffusion, including a furnace mouth 1, a quartz furnace door 5, a sealing flange 4, a graphite sealing gasket 3 and a ceramic fiber packing 2. A sealing flange 4 is provided on the outside of the furnace mouth 1 of the process chamber, and the sealing flange 4 is fixed to the frame by screws and presses the furnace mouth 1 of the process chamber. An outer ring groove and an inner ring groove are provided on the surface of the sealing flange 4 opposite to the furnace mouth 1, a graphite sealing gasket 3 is installed in the outer ring groove, and a ceramic fiber packing 2 is installed in the inner ring groove. The graphite sealing gasket 3 realizes the vacuum sealing of the furnace mouth 1, and the ceramic fiber packing 2 isolates the graphite sealing gasket 3 from polluting the silicon wafer. The quartz furnace door 5 is pressed on the outer side of the sealing flange 4 by a driving cylinder, a sealing groove is provided on the inner side of the quartz furnace door 5, a sealing ring is installed in the sealing groove, and the quartz furnace door 5 and the sealing flange 4 are sealed by a sealing ring.

[0024] The sealing flange 4 realizes vacuum sealing between the sealing flange 4 and the process chamber by squeezing the graphite sealing gasket 3. The graphite sealing gasket 3 can withstand higher temperatures and has a more stable and durable structure. The ceramic fiber packing 2 forms a partition between the vacuum chamber and the graphite sealing gasket 3 to prevent impurities in the graphite sealing gasket 3 from contaminating the silicon wafer in the process chamber, and at the same time can block part of the heat from escaping along the sealing surface of the process chamber and the sealing surface of the sealing flange 4.

[0025] The number of outer ring grooves is preferably 1-2, and when the number of outer ring grooves is more than two, they are distributed in inner and outer concentric circles. The number of inner ring grooves is preferably 1-2, and when the number of inner ring grooves is more than two, they are distributed in inner and outer concentric circles.

[0026] The sealing flange structure of the present invention adopts a graphite sealing gasket, which can withstand higher temperatures than the traditional sealing flange using a rubber sealing ring, without worrying about the high temperature damage of the sealing ring; at the same time, due to the isolation effect of the ceramic fiber packing, the possible pollution of the process chamber by the graphite gasket is effectively prevented. The use of graphite gasket sealing can withstand higher temperatures under the same process conditions, with lower costs and more stable structure.

[0027] The above description is an explanation of the present invention, not a limitation of the present invention. The present invention may be modified in any form without violating the spirit of the present invention.

Claims

1. A boron diffusion process using a graphite sealing gasket, characterized in that: The furnace mouth of the process chamber for boron diffusion adopts the following structure: a sealing flange (4) is provided on the outside of the furnace mouth (1) of the process chamber, the sealing flange (4) is fixedly mounted on the frame and presses the furnace mouth (1) of the process chamber, and a quartz furnace door (5) is pressed on the outside of the sealing flange (4); an outer ring groove and an inner ring groove are provided on the surface of the sealing flange (4) opposite to the furnace mouth (1), a graphite sealing gasket (3) is installed in the outer ring groove, and a ceramic fiber packing (2) is installed in the inner ring groove, the graphite sealing gasket (3) realizes the vacuum sealing of the furnace mouth (1), and the ceramic fiber packing (2) isolates the graphite sealing gasket (3) from contaminating the silicon wafer; A sealing groove is provided on the inner side of the quartz furnace door (5), a sealing ring is installed in the sealing groove, and the quartz furnace door (5) and the sealing flange (4) are sealed by the sealing ring; The sealing flange (4) realizes vacuum sealing between the sealing flange (4) and the process chamber by extruding the graphite sealing gasket (3); The ceramic fiber packing (2) forms a partition between the vacuum chamber and the graphite sealing gasket (3).

2. The boron diffusion process using a graphite gasket according to claim 1, characterized in that: The number of outer ring grooves is 1-2.

3. The boron diffusion process using a graphite gasket according to claim 1, characterized in that: When the number of the outer ring grooves is more than two, they are distributed in inner and outer concentric circles.

4. The boron diffusion process using a graphite gasket according to claim 1, characterized in that: The number of inner ring grooves is 1-2.

5. The boron diffusion process using a graphite gasket according to claim 1, characterized in that: When the number of inner grooves is more than two, they are distributed in inner and outer concentric circles.

6. The boron diffusion process using a graphite gasket according to claim 1, characterized in that: The sealing flange (4) is fixed to the frame by screws.

7. The boron diffusion process using a graphite gasket according to claim 1, characterized in that: The quartz furnace door (5) is pressed against the outer side of the sealing flange (4) by a driving cylinder.

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