Diffusion furnace for diffusion process

Abstract

The diffusion furnace for the diffusion technology comprises a furnace body, a furnace door is connected to the furnace body in a sealed mode, an air inlet main pipe and an air exhaust pipe are connected to one side wall of the furnace body in a sealed mode, the air inlet main pipe is installed on the outer side of the furnace body, a connecting pipe is connected to the air inlet main pipe in a sealed mode, and the air exhaust pipe is installed on the outer side of the furnace body. A furnace tail air inlet pipe and a furnace interior air inlet pipe are connected to the connecting pipe in a sealed mode, the ends, away from the connecting pipe, of the furnace tail air inlet pipe and the furnace interior air inlet pipe are connected with the furnace body in a sealed mode, a first adjusting valve is fixedly installed on the furnace tail air inlet pipe, and a second adjusting valve is fixedly installed on the furnace interior air inlet pipe. And a homogenizing plate and a flow equalizing box are fixedly mounted in the furnace body. Compared with the prior art, the diffusion furnace for the diffusion process has the advantages that the problem of non-uniform concentration of mixed gas in the furnace can be solved under the condition that the strength of the pipe body of the gas inlet pipe is not damaged, and the use cost is effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of diffusion furnaces, and in particular relates to a diffusion furnace used in a diffusion process. Background Art

[0002] In the actual production of silicon solar cells, since P-type silicon wafers are used, an N-type layer needs to be formed to obtain a PN junction, which is usually achieved by diffusing a phosphorus source under high temperature conditions. The main purpose of a diffusion furnace is to dope semiconductor wafers under high temperature conditions, that is, to diffuse the elements phosphorus and boron into silicon wafers, thereby changing and controlling the type, concentration and distribution of the medium in the semiconductor, so as to establish different electrical characteristic areas.

[0003] In order to solve the problems of large differences in the amount of mixed gas deposition source in the furnace and uneven concentration of mixed gas between temperature zones and between battery cells, a large-capacity diffusion furnace often opens multiple outlet holes on the air inlet pipe in the furnace. Although multiple outlet holes can improve the problem of uneven concentration of mixed gas in the furnace, the air inlet pipe currently used is basically a quartz glass tube. The quartz glass tube can withstand the higher temperature of the diffusion furnace during the diffusion process, but the tube body is relatively brittle. When multiple outlet holes are opened on the tube body, it is easy to cause edge collapse and fragmentation. In addition, opening multiple outlet holes will damage the strength of the tube body, affect the service life, and increase the cost of use.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a diffusion furnace for diffusion process.

[0005] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Utility Model Content

[0006] The purpose of the utility model is to provide a diffusion furnace for a diffusion process, which can be used to solve the above-mentioned problem.

[0007] In order to achieve the above-mentioned purpose, a specific embodiment of the utility model provides a diffusion furnace for diffusion process, including a furnace body, a furnace door is sealed on the furnace body, an air intake pipe and an exhaust pipe are sealed on one side wall of the furnace body, the air intake pipe is installed on the outside of the furnace body, a connecting pipe is sealed on the air intake pipe, a furnace tail air intake pipe and a furnace middle air intake pipe are sealed on the connecting pipe, the furnace tail air intake pipe and the furnace middle air intake pipe are sealed with the furnace body at one end away from the connecting pipe, a first regulating valve is fixedly installed on the furnace tail air intake pipe, a second regulating valve is fixedly installed on the furnace middle air intake pipe, a homogenizing plate and a flow equalizing box are fixedly installed on the furnace body, the dual-path air intake of the furnace tail air intake pipe and the furnace middle air intake pipe can even out the uniformity of the mixed gas in the furnace, and the first regulating valve and the second regulating valve can respectively control the air intake amount of the furnace tail air intake pipe and the furnace middle air intake pipe.

[0008] In one or more embodiments of the utility model, the furnace tail air inlet pipe, the furnace middle air inlet pipe and the exhaust pipe pass through one side wall of the furnace body, the furnace middle air inlet pipe and the exhaust pipe extend into the interior of the furnace body, the side wall of the furnace tail air inlet pipe at the air outlet is flush with the inner wall of the furnace body, and the positions of the pipe openings of the furnace tail air inlet pipe and the furnace middle air inlet pipe are different, so that the mixed gas is not concentrated in one place.

[0009] In one or more embodiments of the present invention, the exhaust port of the exhaust pipe is 0.3m-0.4m away from a side wall of the furnace body where a furnace door is installed. The distance between the exhaust port of the exhaust pipe and the furnace door can enable the mixed gas to be smoothly extracted from the furnace body and can also reduce the counter-airflow in the furnace.

[0010] In one or more embodiments of the utility model, the length of the air inlet pipe in the furnace extending into the furnace body is 2.6m-2.75m, and the air outlet of the air inlet pipe in the furnace is located in the middle of the furnace body, which is convenient for conveying mixed gas into the furnace.

[0011] In one or more embodiments of the present utility model, a baffle is fixedly installed on the inner wall of the furnace body, and a pipe hole matching the outer diameter of the exhaust pipe is opened on the baffle. The exhaust pipe passes through the pipe hole on the baffle, and the exhaust pipe is sealed and connected to the baffle. The baffle can support the exhaust pipe to protect it.

[0012] In one or more embodiments of the present utility model, the homogenizing plate is semicircular, and is arranged in an inclined manner relative to the horizontal direction. The straight-edge side wall of the homogenizing plate is fixedly installed on one end side wall of the furnace body, and the arc-shaped side wall of the homogenizing plate is fixedly installed on the inner wall of the furnace body. A sealed space is formed between the homogenizing plate and the furnace body, and the installation position of the homogenizing plate matches the air outlet of the furnace tail air inlet pipe. The homogenizing plate can increase the air outlet cross-section of the furnace tail air inlet pipe, so that the mixed gas in the furnace body diffuses more evenly.

[0013] In one or more embodiments of the present invention, a first flow balancing hole and a second flow balancing hole are provided on the homogenizing plate, and the cross-sections of the first flow balancing hole and the second flow balancing hole are conical. The first flow balancing hole is provided at the upper part of the homogenizing plate, and the second flow balancing hole is provided at the lower part of the homogenizing plate. The conical holes of the first flow balancing hole and the second flow balancing hole can make the mixed gas spray at different distances.

[0014] In one or more embodiments of the present invention, a supporting frame is fixedly installed in the furnace body, and a flow equalizing box is fixedly installed on the lower end surface of the baffle, the position of the flow equalizing box matches the length of the air intake pipe in the furnace body, an opening is provided on one side wall of the flow equalizing box, and the opening matches the outer diameter of the air intake pipe in the furnace, the air intake pipe in the furnace passes through the opening on the flow equalizing box, the pipe wall of the air intake pipe in the furnace is sealed and connected to the side wall of the flow equalizing box, and the air outlet of the air intake pipe in the furnace is in the box body of the flow equalizing box, and the outlet area of ​​the air intake pipe in the furnace is increased by the flow equalizing box, which is beneficial to the diffusion of the mixed gas at the outlet of the air intake pipe in the furnace.

[0015] In one or more embodiments of the present invention, a third flow equalizing hole is provided on the side wall of the flow equalizing box opposite to the opening, and the opening direction of the third flow equalizing hole on the flow equalizing box is inclined upward, and the gas ejected from the third flow equalizing hole can be sprayed on the lower half of the furnace body, so that the concentration of the mixed gas in the furnace is uniform.

[0016] Compared with the prior art, the utility model of a diffusion furnace for diffusion process can improve the problem of uneven concentration of mixed gas in the furnace without damaging the strength of the intake pipe body, thereby effectively reducing the use cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the utility model or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art description. Obviously, the drawings described below are only some embodiments recorded in the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a schematic structural diagram of a diffusion furnace for a diffusion process in one embodiment of the utility model;

[0019] Figure 2 A cross-sectional view of a diffusion furnace for a diffusion process in one embodiment of the utility model;

[0020] Figure 3 This is a schematic structural diagram of a homogenizing plate of a diffusion furnace for a diffusion process in one embodiment of the utility model;

[0021] Figure 4It is a cross-sectional view of a homogenizing plate of a diffusion furnace for a diffusion process in one embodiment of the utility model;

[0022] Figure 5 The utility model is a cross-sectional view of a flow equalizing box of a diffusion furnace for a diffusion process in one embodiment.

[0023] Description of main reference numerals:

[0024] 1. Furnace body; 11. Furnace door; 12. Carrying frame; 13. Baffle; 131. Pipe hole; 14. Homogenizing plate; 141. First flow equalizing hole; 142. Second flow equalizing hole; 15. Flow equalizing box; 151. Opening; 152. Third flow equalizing hole; 2. Air intake main pipe; 21. Air intake pipe at the tail of the furnace; 211. First regulating valve; 22. Air intake pipe in the furnace; 221. Second regulating valve; 23. Exhaust pipe; 3. Connecting pipe. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0026] like Figure 1 and Figure 2 As shown, a diffusion furnace for diffusion process in one embodiment of the utility model comprises a furnace body 1, a furnace door 11 is installed at the furnace mouth of the furnace body 1, and the furnace door 11 is sealed and connected to the opening of the furnace body 1. A furnace tail air intake pipe 21, a furnace air intake pipe 22 and an exhaust pipe 23 are sealed and connected to the side wall at the furnace tail of the furnace body 1. The furnace tail air intake pipe 21 and the furnace air intake pipe 22 convey mixed gas into the furnace body 1, and the exhaust pipe 23 extracts the exhaust gas in the furnace body 1.

[0027] Specifically, the furnace tail air intake pipe 21, the furnace middle air intake pipe 22 and the exhaust pipe 23 penetrate the side wall of the furnace body 1 at the rear end and extend into the furnace body 1. The side wall of the furnace tail air intake pipe 21 at the opening is flush with the side wall of the furnace body 1 at the rear end, the furnace middle air intake pipe 22 extends into the middle of the furnace body 1, and the exhaust pipe 23 is the longest and can reach the furnace mouth of the furnace body 1.

[0028] Preferably, the distance between the outlet of the inlet pipe 22 and the side wall of the furnace body 1 is 2.63-2.75 m, which is more conducive to the diffusion of the mixed gas to the furnace door of the furnace body 1. The distance between the exhaust port of the exhaust pipe 23 and the furnace door of the furnace body 1 is 0.3 m-0.4 m, which can reduce the impact between gases during exhaust and intake in the furnace body 1.

[0029] A support frame 12 is welded inside the furnace body 1. When solar cells are placed in the furnace body 1, the quartz boat with the solar cells can be placed on the support frame 12. In this way, the solar cells can be placed in the center of the furnace body 1, which is more conducive to the uniformity of the contact between the solar cells and the mixed gas in the furnace body 1. At the same time, because the quartz boat with the solar cells is placed on the support frame 12, the exhaust pipe 23 can be protected from damage.

[0030] In order to conveniently control the total amount of gas entering the furnace body 1, a connecting pipe 3 is sealed and connected to the furnace tail air inlet pipe 21 and the furnace middle air inlet pipe 22. The connecting pipe 3 has three communication ports. In addition to the communication ports connected to the furnace tail air inlet pipe 21 and the furnace middle air inlet pipe 22, another communication port of the air inlet main pipe 2 is sealed and connected to the air inlet main pipe 2. In this way, the total amount of mixed gas entering the furnace body 1 only needs to control the amount of mixed gas supplied from the air inlet main pipe 2.

[0031] like Figures 2 to 4 As shown, in order to make the mixed gas entering the furnace body 1 diffuse evenly, a homogenizing plate 14 is fixedly installed inside the furnace body 1. The homogenizing plate 14 is semicircular in shape, and the lower side wall of the homogenizing plate 14 is a straight side. The straight side wall of the homogenizing plate 14 is fixedly installed on the side wall of the tail of the furnace body 1, and the arc-shaped side wall of the homogenizing plate 14 is fixedly connected to the inner wall of the upper part of the furnace body 1.

[0032] Specifically, the homogenizing plate 14 is installed on the inner wall of the furnace body 1 in an inclined direction relative to the horizontal direction of the ground, so that a closed space can be formed between one end surface of the homogenizing plate 14 and the side wall at the furnace tail of the furnace body 1.

[0033] Furthermore, the installation position of the homogenizing plate 14 matches the position of the gas outlet of the furnace tail gas inlet pipe 21 .

[0034] A first flow balancing hole 141 and a second flow balancing hole 142 are provided on the homogenizing plate 14. The first flow balancing hole 141 is provided above the homogenizing plate 14 and close to the top of the furnace body 1, and the second flow balancing hole 142 is provided below the first flow balancing hole 141 and close to the straight side wall of the homogenizing plate 14. The first flow balancing hole 141 and the second flow balancing hole 142 are conical in shape, and the conical directions of the first flow balancing hole 141 and the second flow balancing hole 142 are opposite.

[0035] Specifically, when the air intake main pipe 2 transports the mixed gas into the furnace body 1, it will be blocked by the homogenizing plate 14, and the mixed gas can only flow out from the first flow equalizing hole 141 and the second flow equalizing hole 142. Since the first flow equalizing hole 141 and the second flow equalizing hole 142 are conical, the diameter of the first flow equalizing hole 141 near the outlet of the furnace tail air intake pipe 21 is large, and the diameter of the first flow equalizing hole 141 away from the outlet of the furnace tail air intake pipe 21 is small, so that the mixed gas flowing out of the first flow equalizing hole 141 can be sprayed farther, so that the mixed gas is sprayed on the solar cell in the front half of the furnace body 1. The second flow equalizing hole 142 is opened in the opposite direction to the first flow equalizing hole 141, so that the mixed gas flowing out of the second flow equalizing hole 142 is sprayed on the solar cell in the rear half of the furnace body 1. Since the flow rate of the mixed gas is accelerated, and the flow rates of multiple mixed gases are different, the mixed gas will not be deposited at the outlet of the furnace tail air intake pipe 21, so that the mixed gas in the furnace body 1 is uniform.

[0036] Preferably, the inclination angle of the homogenizing plate 14 is 30 degrees, which is more conducive to the diffusion of the mixed gas in the furnace body 1.

[0037] like Figure 2 and Figure 5 As shown, in order to make up for the problem of low concentration of mixed gas in the lower part near the furnace mouth in the furnace body 1, a flow equalizing box 15 is fixedly installed on the lower panel of the carrier frame 12, and the installation position of the flow equalizing box 15 matches the outlet position of the air inlet pipe 22 in the furnace. An opening 151 is opened on the side wall at one end of the flow equalizing box 15, and the diameter of the opening 151 matches the outer wall diameter of the air inlet pipe 22 in the furnace. The air inlet pipe 22 in the furnace passes through the opening 151 on the flow equalizing box 15, and the air outlet of the air inlet pipe 22 in the furnace is inside the flow equalizing box 15, and the outer wall of the air inlet pipe 22 in the furnace is sealed and connected to the flow equalizing box 15. An opening 151 is opened on the side wall at the other end of the flow equalizing box 15, and the opening direction of the third flow equalizing hole 152 is inclined upward.

[0038] Specifically, the mixed gas delivered from the air outlet of the air inlet pipe 22 in the furnace is concentrated in the cavity of the flow equalizing box 15 and ejected from the third flow equalizing hole 152. Since the opening direction of the third flow equalizing hole 152 is inclined upward, the mixed gas ejected from the third flow equalizing hole 152 can not only increase the concentration of the mixed gas near the lower part of the furnace mouth in the furnace body 1, but also make the concentration of the mixed gas more uniform.

[0039] The exhaust port of the exhaust pipe 23 is located at the furnace mouth. In order to reduce the convection generated when the exhaust pipe 23 extracts the exhaust gas, a baffle 13 is fixedly installed in the furnace body 1. The baffle 13 is provided with a through-tube hole 131 matching the diameter of the outer wall of the exhaust pipe 23, and the exhaust pipe 23 passes through the through-tube hole 131 on the baffle 13. The baffle 13 is semicircular, and the arc-shaped side wall of the baffle 13 is fixedly installed on the inner wall of the furnace body 1, and the straight side wall of the baffle 13 is connected to the lower panel of the support frame 12. The baffle 13 can block the mixed gas ejected from the third flow-balancing hole 152, so that when the furnace body 1 extracts the exhaust gas, the gas flow in the furnace body 1 is more stable.

[0040] When the solar cell enters the furnace body 1, the position can be adjusted on the upper panel of the support frame 12 at the furnace mouth, and the baffle 13 can play a role in strengthening the support frame 12. Since the exhaust pipe 23 is long, the baffle 13 can also play a role in setting up the exhaust pipe 23, making the exhaust pipe 23 more stable in the furnace body 1.

[0041] like Figure 1 and Figure 2 As shown, a first regulating valve 211 is installed on the furnace tail air inlet pipe 21, and a second regulating valve 221 is installed on the furnace inlet pipe 22. When the solar cell is placed in the furnace body 1 and mixed gas is input into the furnace body 1, the first regulating valve 211 and the second regulating valve 221 are all opened, and the furnace tail air inlet pipe 21 and the furnace inlet pipe 22 jointly transport the mixed gas into the furnace body 1, which can improve the working efficiency of the diffusion furnace. At the same time, due to the large amount of mixed gas input, the homogenizing plate 14 and the flow equalizing box 15 can more evenly spray the mixed gas.

[0042] Furthermore, the opening amounts of the first regulating valve 211 and the second regulating valve 221 may be adjusted respectively to control the amount of the mixed gas in the furnace body 1 in different zones.

[0043] When in use, place the solar cell on the support frame 12 in the furnace body 1, close the furnace door 11, and seal the furnace body 1. Open the exhaust pipe 23, and the exhaust pipe 23 will evacuate the furnace body 1. At this time, open the first regulating valve 211 and the second regulating valve 221, and the mixed gas can be transported from the outlet of the furnace tail air inlet pipe 21 and the outlet of the furnace inlet pipe 22 to the furnace body 1. The mixed gas flowing out from the outlet of the furnace tail air inlet pipe 21 is sprayed into the furnace body 1 through the first flow equalizing hole 141 and the second flow equalizing hole 142 on the homogenizing plate 14, and the mixed gas flowing out from the outlet of the furnace inlet pipe 22 is sprayed from the opening 151 on the flow equalizing box 15 toward the furnace door 11 of the furnace body 1, so that the mixed gas in the furnace body 1 is more uniform. After the mixed gas concentration in the furnace body 1 reaches the standard value, the opening size of the first regulating valve 211 and the second regulating valve 221 is adjusted so that the mixed gas input from the furnace tail air inlet pipe 21 and the furnace air inlet pipe 22 and the exhaust gas extracted from the exhaust pipe 23 are connected, making the diffusion process more stable.

[0044] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0045] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A diffusion furnace for a diffusion process, comprising a furnace body, a furnace door being sealedly connected to the furnace body, and an air intake pipe and an exhaust pipe being sealedly connected to a side wall of the furnace body, characterized in that: The air intake main pipe is installed on the outside of the furnace body, and a connecting pipe is sealed on the air intake main pipe. The connecting pipe is sealed on the furnace tail air intake pipe and the furnace middle air intake pipe. The ends of the furnace tail air intake pipe and the furnace middle air intake pipe away from the connecting pipe are sealed with the furnace body. A first regulating valve is fixedly installed on the furnace tail air intake pipe, a second regulating valve is fixedly installed on the furnace middle air intake pipe, and a homogenizing plate and a flow equalizing box are fixedly installed on the furnace body.

2. The diffusion furnace for diffusion process according to claim 1, characterized in that: The furnace tail air inlet pipe, furnace middle air inlet pipe and exhaust pipe penetrate one side wall of the furnace body, the furnace middle air inlet pipe and exhaust pipe extend into the interior of the furnace body, and the side wall of the furnace tail air inlet pipe at the air outlet is flush with the inner wall of the furnace body.

3. The diffusion furnace for diffusion process according to claim 2, characterized in that: The distance between the exhaust port of the exhaust pipe and a side wall of the furnace body on which the furnace door is installed is 0.3m-0.4m.

4. The diffusion furnace for diffusion process according to claim 2, characterized in that: The length of the air inlet pipe in the furnace extending into the furnace body is 2.6m-2.75m.

5. The diffusion furnace for diffusion process according to claim 2, characterized in that: A baffle is fixedly mounted on the inner wall of the furnace body, a through-hole matching the outer diameter of the exhaust pipe is opened on the baffle, the exhaust pipe passes through the through-hole on the baffle, and the exhaust pipe is sealed and connected to the baffle.

6. The diffusion furnace for diffusion process according to claim 2, characterized in that: The homogenizing plate is semicircular and is installed in an inclined manner. The straight side wall of the homogenizing plate is fixedly connected to the side wall of the furnace body, and the arc-shaped side wall of the homogenizing plate is fixedly connected to the top inner wall of the furnace body, forming a sealed space between the homogenizing plate and the furnace body.

7. The diffusion furnace for diffusion process according to claim 6, characterized in that: The homogenizing plate is provided with a first flow balancing hole and a second flow balancing hole, and the cross-sections of the first flow balancing hole and the second flow balancing hole are conical.

8. The diffusion furnace for diffusion process according to claim 5, characterized in that: A carrier is fixedly installed in the furnace body, and a flow balancing box is fixedly installed on the lower end surface of the carrier. The installation position of the flow balancing box matches the position of the air outlet of the air inlet pipe in the furnace.

9. The diffusion furnace for diffusion process according to claim 8, characterized in that: An opening is provided on one side wall of the flow equalizing box, and the opening matches the outer diameter of the air inlet pipe in the furnace. The air inlet pipe in the furnace passes through the opening on the flow equalizing box. The pipe wall of the air inlet pipe in the furnace is sealed and connected to the side wall of the flow equalizing box, and the air outlet of the air inlet pipe in the furnace is inside the body of the flow equalizing box.

10. The diffusion furnace for diffusion process according to claim 9, characterized in that: A third flow balancing hole is opened on the other side wall of the flow balancing box, and the opening direction of the third flow balancing hole on the flow balancing box is inclined upward.

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